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Sample records for noncontact holmium yag

  1. Stone retropulsion during holmium:YAG lithotripsy.

    Science.gov (United States)

    Lee, Ho; Ryan, R Tres; Teichman, Joel M H; Kim, Jeehyun; Choi, Bernard; Arakeri, Navanit V; Welch, A J

    2003-03-01

    We modeled retropulsion during holmium:YAG lithotripsy on the conservation of momentum, whereby the force of ejected fragment debris off of the calculous surface should equal the force of retropulsion displacing the stone. We tested the hypothesis that retropulsion occurs as a result of ejected stone debris. Uniform calculous phantoms were irradiated with holmium:YAG energy in air and in water. Optical fiber diameter and pulse energy were varied. Motion of the phantom was monitored with high speed video imaging. Laser induced crater volume and geometry were characterized by optical coherence tomography. To determine the direction of plume laser burn paper was irradiated at various incident angles. Retropulsion was greater for phantoms irradiated in air versus water. Retropulsion increased as fiber diameter increased and as pulse energy increased (p <0.001). Crater volumes increased as pulse energy increased (p <0.05) and generally increased as fiber diameter increased. Crater geometry was wide and shallow for larger fibers, and narrow and deeper for smaller fibers. The ejected plume propagated in the direction normal to the burn paper surface regardless of the laser incident angle. Retropulsion increases as pulse energy and optical fiber diameter increase. Vector analysis of the ejected plume and crater geometry explains increased retropulsion using larger optical fibers. Holmium:YAG lithotripsy should be performed with small optical fibers to limit retropulsion.

  2. Holmium:YAG laser stapedotomy: preliminary evaluation

    Science.gov (United States)

    Stubig, Ingrid M.; Reder, Paul A.; Facer, G. W.; Rylander, Henry G.; Welch, Ashley J.

    1993-07-01

    This study investigated the use of a pulsed Holmium:YAG ((lambda) equals 2.09 micrometers ) laser- fiber microsurgical system for laser stapedotomy. This system ablates human stapes bones effectively with minimal thermal damage. The study was designed to determine the effectiveness of the Ho:YAG laser (Schwartz Electro Optics, Inc., Orlando, FL) for stapedotomy and to evaluate temperature changes within the cochlea during the ablation process. Human cadaveric temporal bones were obtained and the stapes portion of the ossicular chain was removed. A 200 micrometers diameter low OH quartz fiber was used to irradiate these stapes bones in an air environment. The laser was pulsed at 2 Hz, 250 microsecond(s) ec pulse width and an irradiance range of 100 - 240 J/cm2 was used to ablate holes in the stapes footplate. The resultant stapedotomies created had smooth 300 micrometers diameter holes with a minimum of circumferential charring. Animal studies in-vivo were carried out in chinchillas to determine the caloric spread within the cochlea. A 0.075 mm Type T thermocouple was placed in the round window. Average temperature change during irradiation of the stapes footplate recorded in the round window was 3.6 degree(s)C. The data suggest that stapedotomy using the Ho:YAG laser can result in a controlled ablation of the stapes footplate with minimal thermal damage to the surrounding stapes. Optical coupling using fiberoptic silica fibers is an ideal method for delivering laser energy to the stapes during stapedotomy.

  3. Use of the holmium:YAG laser in urology

    Science.gov (United States)

    Mattioli, Stefano

    1997-12-01

    The Holmium-YAG is a versatile laser with multiple soft- tissue applications including tissue incision and vaporization, and pulsed-laser applications such as lithotripsy. At 2140 nanometers, the wavelength is highly absorbed by tissue water. Further, like CO2 laser, the Holmium produces immediate tissue vaporization while minimizing deep thermal damage to surrounding tissues. It is an excellent instrument for endopyelotomy, internal urethrotomy, bladder neck incisions and it can be used to resect the prostate. The Holmium creates an acute TUR defect which gives immediate results like the TURP. More than 50 patients were treated from Jan. 1996 to Jan. 1997 for obstructive symptoms due to benign prostatic hyperplasia, bladder neck stricture, urethral stenosis, and superficial bladder tumors.

  4. Dynamics of pulsed holmium:YAG laser photocoagulation of albumen

    International Nuclear Information System (INIS)

    Pfefer, T.J.; Welch, A.J.

    2000-01-01

    The pulsed holmium:YAG laser (λ = 2.12 μm, τ p = 250 μs) has been investigated as a method for inducing localized coagulation for medical procedures, yet the dynamics of this process are not well understood. In this study, photocoagulation of albumen (egg white) was analysed experimentally and results compared with optical-thermal simulations to investigate a rate process approach to thermal damage and the role of heat conduction and dynamic changes in absorption. The coagulation threshold was determined using probit analysis, and coagulum dynamics were documented with fast flash photography. The nonlinear computational model, which included a Beer's law optical component, a finite difference heat transfer component and an Arrhenius equation-based damage calculation, was verified against data from the literature. Moderate discrepancies between simulation results and our experimental data probably resulted from the use of a laser beam with an irregular spatial profile. This profile produced a lower than expected coagulation threshold and an irregular damage distribution within a millisecond after laser onset. After 1 ms, heat conduction led to smoothing of the coagulum. Simulations indicated that dynamic changes in absorption led to a reduction in surface temperatures. The Arrhenius equation was shown to be effective for simulating transient albumen coagulation during pulsed holmium:YAG laser irradiation. Greater understanding of pulsed laser-tissue interactions may lead to improved treatment outcome and optimization of laser parameters for a variety of medical procedures. (author)

  5. Performance and safety of holmium: YAG laser optical fibers.

    Science.gov (United States)

    Knudsen, Bodo E; Glickman, Randolph D; Stallman, Kenneth J; Maswadi, Saher; Chew, Ben H; Beiko, Darren T; Denstedt, John D; Teichman, Joel M H

    2005-11-01

    Lower-pole ureteronephroscopy requires transmission of holmium:YAG energy along a deflected fiber. Current ureteroscopes are capable of high degrees of deflection, which may stress laser fibers beyond safe limits during lower-pole use. We hypothesized that optical fiber and safety measures differ among manufacturers. Small (200-273-microm) and medium-diameter (300-400-microm) Ho:YAG fibers were tested in a straight and 180 degrees bent configuration. Energy transmission was measured by an energy detector. Fiber durability was assessed by firing the laser in sequentially tighter bending diameters. The fibers were bent to 180 degrees with a diameter of 6 cm and run at 200- to 4000-mJ pulse energy to determine the minimum energy required to fracture the fiber. The bending diameter was decreased by 1-cm increments and testing repeated until a bending diameter of 1 cm was reached. The maximum deflection of the ACMI DUR-8E ureteroscope with each fiber in the working channel was recorded. The flow rate through the working channel of the DUR-8E was measured for each fiber. The mean energy transmission differed among fibers (P < 0.001). The Lumenis SL 200 and the InnovaQuartz 400 were the best small and medium-diameter fibers, respectively, in resisting thermal breakdown (P < 0.01). The Dornier Lightguide Super 200 fractured repeatedly at a bend diameter of 2 cm and with the lowest energy (200 mJ). The other small fibers fractured only at a bend diameter of 1 cm. The Sharplan 200 and InnovaQuartz Sureflex 273T were the most flexible fibers, the Lumenis SL 365 the least. The flow rate was inversely proportional to four times the power of the diameter of the fiber. Optical performance and safety differ among fibers. Fibers transmit various amounts of energy to their cladding when bent. During lower-pole nephroscopy with the fiber deflected, there is a risk of fiber fracture from thermal breakdown and laser-energy transmission to the endoscope. Some available laser fibers

  6. [Comparison of validity and safety between holmium: YAG laser and traditional surgery in partial nephrectomy].

    Science.gov (United States)

    Bi, Sheng; Xia, Ming

    2015-08-11

    To compare the validity and safety between holmium: YAG laser and traditional surgery in partial nephrectomy. A total of 28 patients were divided into two groups (holmium: YAG laser group without renal artery clamping and traditional surgery group with renal artery clamping). The intraoperative blood loss, total operative time, renal artery clamping time, postoperative hospital stay, separated renal function, postoperative complications and depth of tissue injury were recorded. The intraoperative blood loss, total operative time, renal artery clamping time, postoperative hospital stay, separated renal function, postoperative complications and depth of tissue injury were 80 ml, 77 min, 0 min, 7.4 days, 35 ml/min, 0, 0.9 cm, respectively, in holmium: YAG laser group. And in traditional surgery group were 69 ml, 111 min, 25.5 min, 7.3 days, 34 ml/min, 0, 2.0 cm, respectively. The differences of total operative time, renal artery clamping time and depth of tissue injury between two groups were statistically significant. The others were not statistically significant. Holmium: YAG laser is effective and safe in partial nephrectomy. It can decrease the total operative time, minimize the warm ischemia time and enlarge the extent of surgical excision.

  7. Evaluation of erbium:YAG and holmium:YAG laser radiation and dental hard tissue

    Science.gov (United States)

    Attrill, David Cameron

    Lasers have become increasingly established in medicine as effective alternatives or adjuncts to conventional techniques. In dentistry, several clinical laser systems have been developed and marketed, but their applications have been limited to soft tissue surgery. To date, no laser has been capable of effectively cutting or modifying the highly mineralised dental tissues of enamel and dentine. The aim of this study was to evaluate two new laser systems for use in dentistry through a series of in vitro experiments. Both generic erbium and holmium lasers have theoretically superior operating characteristics over currently established lasers for applications with dental hard tissues. The two lasers investigated in this study were pulsed Er:YAG (lambda=2.94) a.m. and Cr-Tm-Ho:YAG (lambda=2.1mu.m). Both operated with a macropulse duration of approximately 200lambdas, at pulse repetition rates of 2-8Hz and mean pulse energies up to 230mJ. Radiation was focused using CaF[2] lenses (f=50-120mm). The lasers could be operated with or without the addition of a surface water film at the interaction site. Tissue removal efficiency was expressed as a latent heat of ablation (LHA, kJ/cm[3]) using a modification of the technique described by Charlton et al. (1990). The mean LHA's for the Er:YAG laser were 6.24kJ/cm[3] and 22.99kJ/cm[3] with dentine and enamel respectively without water, and 10.07kJ/cm[3] and 18.73kJ/cm[3] for dentine and enamel with water. The Cr-Tm-Ho:YAG laser was unable to effectively remove enamel at the fluences and pulse energies available; the mean LHA's for the Cr-Tm- Ho:YAG laser with dentine were 82.79kJ/cm3 and 57.57kJ/cm3 with and without water respectively. The Cr-Tm-Ho;YAG was approximately 8-9 times less efficient for tissue removal than the Er:YAG system. Er:YAG tissue removal with water was characterised by clean "surgical" cuts, comparable in histological appearance to those obtained using conventional instrumentation. Some thermal disruption

  8. Holmium:YAG laser effects on articular cartilage metabolism: in vitro

    Science.gov (United States)

    Smith, R. Lane; Montgomery, L.; Fanton, G.; Dillingham, M.; Schurman, D. J.

    1994-09-01

    We report effects of applying variable doses of Holmium:YAG laser energy to bovine articular cartilage in vitro. The response of the cartilage to the Holmium:YAG laser energy was determined by quantification of cell proliferation and extracellular matrix glycosaminoglycan synthesis. This study demonstrates that articular cartilage cell metabolism was maintained at a normal level following treatment of cartilage at a dose of 0.6 joules/pulse. The laser energy was applied at 10 Hz for 10 seconds at 1 mm distance from the cartilage. Under these conditions and at a dose of 0.6 joules/pulse, the total energy density was calculated to be 240 joules/cm2, assuming minimal loss of energy due to water absorption. Energy levels grater than 0.8 joules/pulse corresponding to calculated energy densities greater than 320 joules/cm2 proved harmful to cartilage. Our data demonstrate that low levels of Holmium:YAG laser energy can be applied to articular cartilage under conditions that maintain and/or stimulate cell metabolism.

  9. Lumbar endoscopic percutaneous discolisis, with Holmium YAG laser - four years of experience

    International Nuclear Information System (INIS)

    Ramirez L, Jorge Felipe; Rugeles O, Jose G

    2001-01-01

    we have designed a prospective study over 220 patients with lumbar hernia. our purpose is to show the results that we have obtained with endoscopic percutaneous holmium YAG laser lumbar disc decompression. In all cases, ambulatory surgery was performed using local anesthesia, follow up based on Mac Nab criteria was made with excellent and good results in 75% of patients this is a useful safety outpatient procedure with good results, fewer complications, reduced costs and with the same or better results than traditional procedures

  10. Noncontact Er:YAG laser ablation: clinical evaluation.

    Science.gov (United States)

    Dostálová, T; Jelínková, H; Kucerová, H; Krejsa, O; Hamal, K; Kubelka, J; Procházka, S

    1998-10-01

    The aim of this study is to evaluate the quality of laser ablation in comparison with the classical drilling preparation. For the experiment, the Er:YAG laser drilling machine was used. The system had a laser head, water cooler, and power supply with automatic control. Spot size of 300-350 microns was used for the preparation. Repetition rate of 1-4 Hz, and pulse energies of 100-400 mJ with water spray were chosen. Cavity shape in comparison with classical drill, time of preparation, and influence of cavity shape on filling materials retention in accordance with the U.S. Public Health Service System were used. The evaluation criteria for noncontact Er:YAG ablation were done. The cavity shape is irregular, but spot surface has larger area and microretentive appearance. Caries of enamel and dentin were treated with a noncontact preparation. It was possible to remove the old insufficient fillings, except for amalgam or metal alloys. The average number of pulses was 111.22 (SE 67.57). Vibrations of microexplosions during preparation were felt by patients on 14 cavities; however, nobody felt unpleasant pain. The qualities of filling materials in laser cavities were very stable; however, cavo surface margin discoloration of 82-86% of Alfa rating could be a problem. Changes of the color and anatomic form of the tooth were observed in 4-8%. In comparison with the classical treatment, it could be said that the retention and quality of filling materials is the same or very similar.

  11. Alternative Treatment of Osteoma Using an Endoscopic Holmium-YAG Laser

    Directory of Open Access Journals (Sweden)

    Ba Leun Han

    2012-07-01

    Full Text Available Osteoma is one of the most common tumors of the cranial vault and the facial skeleton. For osteoma in the facial region, endoscopic resection is widely used to prevent surgical scarring. Tumors in a total of 14 patients were resected using an endoscopic holmium-doped yttrium aluminium garnet (Ho:YAG laser with a long flexible fiber. Aside from having the advantage of not leaving a scar due to the use of endoscopy, this procedure allowed resection at any position, was minimally invasive, and caused less postoperative pain. This method yielded excellent cosmetic results, so the endoscopic Ho:YAG laser is expected to emerge as a good treatment option for osteoma.

  12. Acute and chronic response of meniscal fibrocartilage to holmium:YAG laser irradiation

    Science.gov (United States)

    Horan, Patrick J.; Popovic, Neven A.; Islinger, Richard B.; Kuklo, Timothy R.; Dick, Edward J.

    1997-05-01

    The acute and chronic (10 week) histological effects of the holmium:YAG laser during partial meniscectomy in an in vivo rabbit model were investigated. Twenty-four adult male New Zealand rabbits underwent bilateral parapatellar medial knee arthrotomies. In the right knee, a partial medial meniscectomy was done through the avascular zone using a standard surgical blade. In the left knee, an anatomically similar partial medial meniscectomy was performed using a Ho:YAG laser (Coherent, USA). This study indicates that the laser creates two zones of damage in the meniscal fibrocartilage and that the zone of thermal change may act as a barrier to healing. The zone of thermal change which is eventually debrided was thought at the time of surgery to be viable. In the laser cut menisci, the synovium appears to have greater inflammation early and to be equivalent with the scalpel cut after three weeks. At all time periods there appeared more cellular damage in the laser specimens.

  13. Laboratory investigation of the efficacy of holmium:YAG laser irradiation in removing intracanal debris

    Science.gov (United States)

    Nuebler-Moritz, Michael; Gutknecht, Norbert; Sailer, Hermann F.; Hering, Peter; Prettl, Wilhelm

    1997-05-01

    Current endodontic therapy involves debridement and disinfection of the root canal by means of mechanical instrumentation and chemical irrigation. However, several studies have shown that these techniques fail to achieve complete cleansing. Recently, lasers have been suggested for use within root canals. This study was conducted to determine the efficacy of Holmium:YAG laser irradiation in removing intracanal debris and smear layer. Root canal surfaces of freshly-extracted human teeth were exposed to pulsed Ho:YAG laser radiation. Subsequently, laser induced structural changes were investigated using scanning electron microscopy. Temperature measurements during irradiation were performed by means of thermocouples. The result of this survey give a preliminary indication of the ability of the Ho:YAG laser to improve current endodontic treatment survey give a preliminary indication of the ability of the Ho:YAG laser to improve current endodontic treatment modalities. However, limitations exist with regard to circumscribed and well-quantified irradiation of root canal surfaces, due to the lack of perpendicular delivery of the laser beam. Additional studies will be required to develop suitable optical transmission systems, in order to achieve complete cleansing and to avoid damage to the periradicular tissues, respectively.

  14. Bouveret's syndrome complicated by distal gallstone ileus after laser lithotropsy using Holmium: YAG laser

    Directory of Open Access Journals (Sweden)

    Rodgers John B

    2002-06-01

    Full Text Available Abstract Background Bouveret's syndrome is an unusual presentation of duodenal obstruction caused by the passage of a large gallstone through a cholecystoduodenal fistula. Endoscopic therapy has been used as first-line treatment, especially in patients with high surgical risk. Case presentation We report a 67-year-old woman who underwent an endoscopic attempt to fragment and retrieve a duodenal stone using a Holmium: Yttrium-Aluminum-Garnet Laser (Ho:YAG which resulted in small bowel obstruction. The patient successfully underwent enterolithotomy without cholecystectomy or closure of the fistula. Conclusion We conclude that, distal gallstone obstruction, due to migration of partially fragmented stones, can occur as a possible complication of laser lithotripsy treatment of Bouveret's syndrome and might require urgent enterolithotomy.

  15. Transurethral lithotripsy with holmium-YAG laser of a large exogenous prostatic calculus.

    Science.gov (United States)

    Hasegawa, Masanori; Ohara, Rei; Kanao, Kent; Nakajima, Yosuke

    2011-04-01

    Prostatic calculi are classified into two types, endogenous and exogenous calculi, based on their origin. Endogenous calculi are commonly observed in elderly men; however, exogenous prostatic calculi are extremely rare. We report here the case of a 51-year-old man who suffered incontinence and pollakiuria with a giant exogenous prostatic calculus almost completely replacing the prostatic tissue. X-rays and computed tomography demonstrated a large calculus of 65 × 58 mm in the small pelvic cavity. The patient underwent a transurethral lithotripsy with a holmium-YAG laser and a total of 85 g of disintegrated stones was retrieved and chemical stone analysis revealed the presence of magnesium ammonium phosphate. The incontinence improved and the voiding volume increased dramatically, and no stone recurrence in the prostatic fossa occurred at the 2 years follow-up. The etiology of this stone formation seemed to be based on some exogenous pathways combined with urinary stasis and chronic urinary infection due to compression fracture of the lumbar vertebra.

  16. Efficacy of holmium. Yttrium-aluminium-garnet (Ho: YAG) laser therapy for arthroscopic synovectomy of rheumatoid arthritis

    International Nuclear Information System (INIS)

    Inoue, Yasuo; Inoue, Kazuhiko; Kanbe, Katsuaki

    2008-01-01

    To clarify the efficacy of holmium: yttrium-aluminium-garnet (Ho: YAG) laser therapy for arthroscopic synovectomy of rheumatoid arthritis (RA), we treated 13 shoulders of 11 RA patients of whom 1 was stage I, 7 stage II, 2 stage III, and 1 stage IV. The duration of RA is 4.6 years on average and the follow-up period is an average of 14 months. The Ho: YAG laser was set at 10 Watt (W) to treat the bone erosion areas so as to reach the deep zones of the pannus in order to resect the synovium. We compared C-reactive protein (CRP), Disease activity score (DAS) 28 and magnetic resonance image (MRI) findings before and after surgery. We cultured primary synovial cells to assay cytokine production of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α. Morphological examination was performed after treatment with the Ho: YAG laser at 0, 1, 5, 10, 15 and 20 W. We found villous synovium proliferation with vascularity in the rotator interval and supra spinatus tendon in the shoulder joints. In the subacromial bursa, yellow fat tissue and white fibrous soft tissue were detected in almost all shoulders. After synovectomy using the Ho: YAG laser, CRP decreased from an average of 3.6 to 0.8 and DAS28 also decreased from an average of 5.4 to 3.7 at 14 months after surgery. MRI showed decreased panni with synovium and did not precede joint destruction after 14 months in 10 shoulders out of 13 (77%). At 20 W of the Ho: YAG laser treatment, the synovial cells shrank as in apoptosis and the number of cells also decreased. Laser treatment also resulted in the following significant changes: TNF-α production increased at 1, 10, 15 and 20 W (compared with 0 W) but not dose dependently; IL-1β and IL-6 increased up to 10 W (compared with 0 W) but decreased at 15 and 20 W (compared with 10 W). In morphological examination, after treatment with the Ho: YAG laser at 15 W, the synovial cells expanded and the number of cells decreased. Therefore, Ho: YAG laser therapy is effective

  17. Pulsed liquid jet dissector using holmium: YAG laser - a novel neurosurgical device for brain incision without imparing vessels

    International Nuclear Information System (INIS)

    Hirano, T.; Nakagawa, A.; Jokura, H.; Shirane, R.; Uenohara, H.; Ohyama, H.; Takayama, K.

    2003-01-01

    Neurosurgery has long required a method for dissecting brain tissue without damaging principal vessels and adjacent tissue, so as to prevent neurological complications after operation. In this study we constructed a prototype of such a device and used it in an attempt to resect beagle brain cortex. The prototype device consisted of an optical fiber, a Y adapter, and a nozzle whose internal exit diameter was 100 μm. Cold physiological saline (4 o C) was supplied to it at a rate of 40 ml/h. Pulsed liquid jets were ejected from the nozzle by a pulsed Holmium:YAG) (Ho:YAG) laser at an irradiation energy of 300 mJ/pulse. The profile of the liquid jet was observed with a high-speed camera while changing the distance between the optical fiber end and nozzle exit (equivalent to the Standoff distance). With this device (3 Hz operation), brain dissection of anesthetized beagles was attempted while measuring the local temperature of the target. A histological study of the incised parts was also performed. When the Standoff distance was 24 mm, the liquid jet was emitted straight from the nozzle at a maximum initial velocity of 50 m/s. The brain parenchyma was cut with this device while preserving vessels larger than 200 μm in diameter and keeping the operative field clear. The local temperature rose to no more than 41 o C, below the functional heat damage threshold of brain tissue. Histological findings showed no signs of thermal tissue damage around the dissected margin. The Ho:YAG laser-induced liquid jet dissector can be applied to neurosurgery after incorporating some minor improvements. (author)

  18. Low-power holmium:YAG laser urethrotomy for treatment of urethral strictures: functional outcome and quality of life.

    Science.gov (United States)

    Kamp, Stefan; Knoll, Thomas; Osman, Mahmoud M; Köhrmann, Kai Uwe; Michel, Maurice S; Alken, Peter

    2006-01-01

    To evaluate the efficacy of endourethrotomy with the holmium:YAG laser as a minimally invasive treatment for urethral stricture. Between January 2002 and January 2004, 32 male patients with symptomatic urethral strictures (8 bulbar, 9 penile, 9 combined) were treated with Ho:YAG-laser urethrotomy in our department. The stricture was iatrogenic in 60% (N = 18), inflammatory in 16.6% (N = 5), traumatic in 13.3% (N = 4), and idiopathic in 7% (N = 3). The stricture was incised under vision at the 12 o'clock location or the site of maximum scar tissue or narrowing in asymmetric strictures. Laser energy was set on 1200 to 1400 mJ with a frequency of 10 to 13 Hz. Postoperatively, drainage of the bladder was performed for 4 days using a 18F silicone catheter. Triamcinolone was instilled intraurethrally after removal of the catheter in all patients. Patients were followed up by mailed questionnaire, including International Prostate Symptom Score and quality of life. Retrograde endoscopic Ho:YAG laser urethrotomy could be performed in all 32 patients. Most patients (22; 68.7%) did not need any reintervention. Ten patients developed recurrent strictures that were treated by another laser urethrotomy in 4 patients (12.5%), while 6 patients (18.7%) needed open urethroplasty with buccal mucosa. Including 2 patients treated with repeat laser urethrotomy, 24 patients (75%) were considered successful after a mean follow-up of 27 months (range 13-38 months). No intraoperative complications were encountered, although in 5% of patients, a urinary-tract infection was diagnosed postoperatively. No gross hematuria occurred. The Ho:YAG laser urethrotomy is a safe and effective minimally invasive therapeutic modality for urethral stricture with results comparable to those of conventional urethrotomy. Further data from long-time follow-up are necessary to compare the success rate with that of conventional urethrotomy and urethroplasty. Nevertheless, the Ho:YAG laser urethrotomy might at

  19. Er:YAG and CTH:YAG laser radiation: contact versus non-contact enamel ablation and sonic-activated bulk composite placement

    International Nuclear Information System (INIS)

    Buckova, M; Kasparova, M; Dostalova, T; Jelinkova, H; Sulc, J; Nemec, M; Fibrich, M; Bradna, P; Miyagi, M

    2013-01-01

    Laser radiation can be used for effective caries removal and cavity preparation without significant thermal effects, collateral damage of tooth structure, or patient discomfort. The aim of this study was to compare the quality of tissue after contact or non-contact Er:YAG and CTH:YAG laser radiation ablation. The second goal was to increase the sealing ability of hard dental tissues using sonic-activated bulk filling material with change in viscosity during processing. The artificial caries was prepared in intact teeth to simulate a demineralized surface and then the Er:YAG or CTH:YAG laser radiation was applied. The enamel artificial caries was gently removed by the laser radiation and sonic-activated composite fillings were inserted. A stereomicroscope and then a scanning electron microscope were used to evaluate the enamel surface. Er:YAG contact mode ablation in enamel was quick and precise; the cavity was smooth with a keyhole shaped prism and rod relief arrangement without a smear layer. The sonic-activated filling material was consistently regularly distributed; no cracks or microleakage in the enamel were observed. CTH:YAG irradiation was able to clean but not ablate the enamel surface; in contact and also in non-contact mode there was evidence of melting and fusing of the enamel. (paper)

  20. Er:YAG and CTH:YAG laser radiation: contact versus non-contact enamel ablation and sonic-activated bulk composite placement

    Science.gov (United States)

    Buckova, M.; Kasparova, M.; Dostalova, T.; Jelinkova, H.; Sulc, J.; Nemec, M.; Fibrich, M.; Bradna, P.; Miyagi, M.

    2013-05-01

    Laser radiation can be used for effective caries removal and cavity preparation without significant thermal effects, collateral damage of tooth structure, or patient discomfort. The aim of this study was to compare the quality of tissue after contact or non-contact Er:YAG and CTH:YAG laser radiation ablation. The second goal was to increase the sealing ability of hard dental tissues using sonic-activated bulk filling material with change in viscosity during processing. The artificial caries was prepared in intact teeth to simulate a demineralized surface and then the Er:YAG or CTH:YAG laser radiation was applied. The enamel artificial caries was gently removed by the laser radiation and sonic-activated composite fillings were inserted. A stereomicroscope and then a scanning electron microscope were used to evaluate the enamel surface. Er:YAG contact mode ablation in enamel was quick and precise; the cavity was smooth with a keyhole shaped prism and rod relief arrangement without a smear layer. The sonic-activated filling material was consistently regularly distributed; no cracks or microleakage in the enamel were observed. CTH:YAG irradiation was able to clean but not ablate the enamel surface; in contact and also in non-contact mode there was evidence of melting and fusing of the enamel.

  1. Comparison of cold-knife optical internal urethrotomy and holmium:YAG laser internal urethrotomy in bulbar urethral strictures

    Science.gov (United States)

    Yenice, Mustafa Gurkan; Sam, Emre; Colakoglu, Yunus; Atar, Feyzi Arda; Sahin, Selcuk; Simsek, Abdulmuttalip; Tugcu, Volkan

    2017-01-01

    Introduction To compare the results of cold-knife optical internal urethrotomy (OIU) and Holmium:YAG laser internal urethrotomy (HIU) in primary bulbar urethral strictures. Material and methods A total of 63 patients diagnosed with primary bulbar urethral stricture between August 2014 and September 2015 were assigned to the OIU (n = 29) and HIU (n = 34) groups. The demographic variables, biochemistry panels, and preoperative and postoperative uroflowmetry results including the maximum flow rate (Qmax) and mean flow rate (Qmean) values, retrograde urethrography, and diagnostic flexible urethroscopy findings were recorded prospectively. Demographic features and preoperative values were not statistically different between groups (p >0.05). Mean surgical times were 18.4 ±2.3 min for OIU and 21.9 ±3.8 min for HIU groups, which was statistically significant (p 0.05). There was no recurrence in the first 3 months in either group. The urethral stricture recurrence rate up to month 12 was not statistically significant for the OIU group (n = 6, 20.7%) as compared to the HIU group (n = 11, 32.4%; p = 0.299). At follow-up, the SFR and IFR was 96% and 88% at 3-months, and 82% and 71% at 12-months, respectively (p method to OIU, and it has similar success rates in the treatment of short segment bulbar urethral strictures. PMID:29732217

  2. Combined retrograde flexible ureteroscopic lithotripsy with holmium YAG laser for renal calculi associated with ipsilateral ureteral stones.

    Science.gov (United States)

    Cocuzza, Marcello; Colombo, Jose R; Ganpule, Arvind; Turna, Burak; Cocuzza, Antonio; Dhawan, Divyar; Santos, Bruno; Mazzucchi, Eduardo; Srougi, Miguel; Desai, Mahesh; Desai, Mihir

    2009-02-01

    The purpose of this study was to evaluate the effectiveness of combined ureteroscopic holmium YAG lithotripsy for renal calculi associated with ipsilateral ureteral stones. Between August 2002 and March 2007, retrograde flexible ureteroscopic stone treatment was attempted in 351 cases. Indication for treatment was concurrent symptomatic ureteral stones in 63 patients (group I). Additional operative time and perioperative complication rates were compared to a group of 39 patients submitted to ureteroscopic treatment for ureteral calculi exclusively (group II). Mean ureteral stone size was 8.0 +/- 2.6 mm and 8.1 +/- 3.4 mm for groups I and II, respectively. Mean operative time for group I was 67.9 +/- 29.5 minutes and for group 2 was 49.3 +/- 13.2 minutes (p stone size was 10.7 +/- 6.4 mm, overall stone free rate in group I was 81%. However, considering only patients with renal stones smaller than 15 mm, the stone free rate was 88%. Successful treatment occurred in 81% of patients presenting lower pole stones, but only 76% of patients with multiple renal stones became stone free. As expected, stone free rate showed a significant negative correlation with renal stone size (p = 0.03; r = -0.36). Logistic regression model indicated an independent association of renal stones smaller than 15 mm and stone free rate (OR = 13.5; p = 0.01). Combined ureteroscopic treatment for ureteral and ipsilateral renal calculi is a safe and attractive option for patients presenting for symptomatic ureteral stone and ipsilateral renal calculi smaller than 15 mm.

  3. Do We Really Need to Wear Proper Eye Protection When Using Holmium:YAG Laser During Endourologic Procedures? Results from an Ex Vivo Animal Model on Pig Eyes.

    Science.gov (United States)

    Villa, Luca; Cloutier, Jonathan; Compérat, Eva; Kronemberg, Peter; Charlotte, Frederic; Berthe, Laurent; Rouchausse, Yann; Salonia, Andrea; Montorsi, Francesco; Traxer, Olivier

    2016-03-01

    We sought to evaluate the effect of holmium:yttrium-aluminum-garnet (Ho:YAG) laser exposure on ex vivo pig eyes and to test the protective action of different glasses in preventing eye lesions in case of accident. We pointed the tip of a Ho:YAG laser fiber from different distances (0, 3, 5, 8, 10, and 20 cm, respectively) toward the center of the pupil of the pig eye. The Ho:YAG laser was activated for 1 or 5 seconds at three different settings (0.5 J-20 Hz, 1 J-10 Hz, and 2 J-10 Hz, respectively). The experiment was repeated using laser safety glasses and eyeglasses. A total of 78 pig eyes were used. The effects of the Ho:YAG laser on pig eyes were assessed by histopathology. Comparable laser emission experiments were performed on thermal paper at different distances using different pulse energies. Ho:YAG laser-induced corneal lesions were observed in unprotected eyes, ranging from superficial burning lesions to full-thickness necrotic areas, and were directly related to pulse energy and time of exposure and inversely related to the distance from the eye. When the laser was placed 5 cm or more, no corneal damage was observed regardless of the laser setting and the time of exposure. Similar distance/energy level relationships were observed on thermal paper. No damage was observed to the lens or the retina in any of the Ho-YAG laser-treated eyes or in any of the eyes protected by laser safety and eyeglasses. Ho:YAG lasers can cause damage when set to high energy, but only to the cornea, from close distances (0-5 cm) and in the absence of eye protection. Eyeglasses are equally effective in preventing laser damage as laser safety glasses.

  4. Use of the Stone Cone for prevention of calculus retropulsion during holmium:YAG laser lithotripsy: case series and review of the literature.

    Science.gov (United States)

    Eisner, Brian H; Dretler, Stephen P

    2009-01-01

    Stone retropulsion during ureteroscopic lithotripsy leads to additional procedures for residual calculi. The Stone Cone (Boston Scientific, Natick, Mass., USA) is a device designed to prevent stone migration. To determine the incidence of calculus retropulsion and additional procedures after ureteroscopy with intracorporeal lithotripsy while using the Stone Cone. A retrospective review of patients with obstructing ureteral calculi who underwent ureteroscopy and holmium:YAG laser lithotripsy using the Stone Cone as a backstop over a 3-year period at an academic medical center was performed. 133 patients underwent ureteroscopy with holmium:YAG laser lithotripsy using the Stone Cone to prevent calculus retroplusion. Success was defined as no residual fragments >2 mm in size, no changes from semirigid to flexible ureteroscope, and no additional procedures. Post-operative imaging was abdominal plain radiography or computed tomography. A MEDLINE search was performed to indentify all English clinical studies of the Stone Cone. Of the 133 uses of the Stone Cone, there were 2 (1.5%) residual retropulsed fragments >2 mm which required an additional procedure. There were no changes to flexible ureteroscope secondary to stone retropulsion in 105 cases of semirigid ureteroscopy. There was no instance of ureteral obstruction from residual 2-mm fragments. There were no ureteral strictures or hydronephrosis among 91 patients with long-term follow-up imaging. A review of the literature was performed which yielded 4 clinical publications and 90 reported cases using the Stone Cone with 100% success. Two of these studies showed statistically significant improvement when compared with control patients. The Stone Cone minimized stone retropulsion during ureteroscopic laser lithotripsy. The Stone Cone offers the urologist greater certainty during ureteroscopy and may decrease the number of clinically significant residual calculi. Copyright 2009 S. Karger AG, Basel.

  5. Holmium:YAG Laser Ablation for the Management of Lower Urinary Tract Foreign Bodies Following Incontinence Surgery: A Case Series and Systematic Review.

    Science.gov (United States)

    Chan, Garson; Mamut, Adiel; Martin, Paul; Welk, Blayne

    2016-11-01

    The objective of this study was to determine the outcomes associated with the endoscopic removal of foreign bodies (such as mesh or permanent suture) in the lower urinary tract after female stress incontinence surgery with the Holmium:YAG (Ho:YAG) laser, and to systematically review the literature on this topic. A retrospective chart review of 18 consecutive women found to have mesh or suture exposure was performed. All patients underwent Ho:YAG laser ablation. A systematic review was performed to identify literature addressing the endoscopic management of mesh/suture exposure after stress incontinence surgery. Between November 2011 and February 2016, 18 women underwent Ho:YAG laser ablation of exposed mesh or suture. Presenting symptoms included lower urinary tract symptoms, pelvic pain, incontinence, or recurrent urinary tract infections. Thirteen women had a previous synthetic midurethral sling and five had a prior retropubic suspension. The median age was 58 years (interquartile range [IQR] 50-60) and median follow-up was 2 years (IQR 1-2). Four patients (22%) had residual mesh after the first procedure, requiring a repeat endoscopic procedure. Only one patient had a small amount of asymptomatic residual mesh on cystoscopy after the final procedure. Only minor postoperative complications were observed. Eight patients had stress incontinence and four underwent operative treatment for this. In our systematic review, we identified 16 case series, which described a total of 158 patients. Women most commonly presented with voiding symptoms or incontinence. Based on the synthesis of these data, repeat procedures were necessary in 16% and vesicovaginal fistula occurred in 2%. Recurrent/persistent stress incontinence was present in 20%, and of these patients, 3/4 underwent a new stress incontinence procedure. Both our case series and the systematic review of the literature demonstrated that endoscopic treatment of lower urinary tract foreign bodies after stress

  6. Evaluation of Bone Healing After Osteotomies Prepared With Er:YAG Laser in Contact and Noncontact Modes and Piezosurgery--An Animal Study.

    Science.gov (United States)

    Gabrić, Dragana; Blašković, Marko; Gjorgijevska, Elizabeta; Mladenov, Mitko; Tašič, Blaž; Jurič, Ivona Bago; Ban, Ticijana

    2016-01-01

    To analyze the healing of bone tissue treated with Er:YAG laser contact and noncontact modes of and piezosurgery in a rat model using triangular laser profilometry. Twenty-four 10-week-old adult male Wistar rats were used in the study. Three osteotomies on the medial part of tibia were performed in each animal, 1 in the right tibia and 2 in the left tibia. The osteotomies were performed with a piezoelectric device set at maximal power and the Er:YAG laser in contact mode (power, 7.5 W; pulse energy, 375 mJ; repetition rate, 20 Hz; MSP mode) and noncontact mode (power, 7.5 W; pulse energy, 750 mJ; repetition rate, 10 Hz; QSP mode) with a novel type of circular, digitally controlled handpiece (x-Runner). After surgery, 6 animals were immediately euthanized (group 1), and the others were euthanized after 1 week (group 2, n = 6), 2 weeks (group 3, n = 6), and 3 weeks (group 4, n = 6). Bone healing after osteotomy was analyzed using a 3-dimensional laser scanning technique (ie, laser triangulation profilometry). The volume reduction rates are similar for all 3 techniques (0.2 to 0.25 mm(3) per week). Greater volume reduction of 0.25 mm3 per week was observed for the Er:YAG laser in noncontact mode (x-Runner). After 3 weeks, almost complete healing of the prepared osteotomy was observed. Within the limitations of this study, the osteotomies performed by the Er:YAG laser in digitally controlled noncontact mode healed the fastest. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  7. Efficacy and Safety of Semirigid Ureteroscopy Combined with Holmium: YAG Laser in the Treatment of Upper Urinary Tract Calculi: Is it a Good Alternative Treatment Option of Flexible Ureteroscopy for Developing Countries

    International Nuclear Information System (INIS)

    Bibi, S.; Siddiqui, T. R.; Ahmed, W.; Alam, S. E.; Shah, S. A.; Soomro, I. A.; Qureshi, S.

    2015-01-01

    Objective: To assess the success rates of endoscopic management of upper ureteral stones using semirigid ureterorenoscopy and holmium: YAG laser lithotripters. Method: A total of 74 patients with an established diagnosis of upper ureteric stone and scheduled for endoscopic ureteral stone treatment were retrospectively evaluated. Failure was defined as the inability to contact or fragment the stone, migration of the stone into the renal pelvis and difficulty in visualizing the stone for the second time. Success rates and influencing factors as for stone-free state were investigated. Results: Mean age of our patients was 45.99±15.00 (range: 24-82) years. In 14 of 74 patients procedural failure was observed. Double J stents were implanted in 65 percent of the patients and ureteral catheterization was performed on 20 percent of them. The total success rate was 81.1 percent. Major complication rate was 1.1 percent. Factors effecting the success rate as gender, age, body mass index, grade of hydronephrosis and stone size were evaluated and only age was found to be statistically significant. Conclusion: Despite some potential risks, semirigid ureterorenoscopic stone extraction and holmium: YAG laser lithotripters are still safe and effective treatment alternatives for management of upper ureteral stones. (author)

  8. Efeito do Hólmio YAG laser (Ho: YAG sobre o tendão patelar de ratos após 12 e 24 semanas de seguimento The effects of Holmium YAG laser (Ho:YAG on the patellar tendon of rats after 12 and 24 weeks of follow up

    Directory of Open Access Journals (Sweden)

    Waldo Lino Júnior

    2005-01-01

    , com neoformação vascular evidente. No grupo de 24 semanas as fibras de colágeno se apresentavam com disposição regular e paralela ao longo eixo do tendão.The authors have studied the effects of the Holmium: Yttrium Aluminum Grenade (Ho:YAG laser on tendon sizes (proximal and distal length and width and on the cellularity and arrangement of collagen fibers in 20 Wistar variety, male, white, adult rats (Rattus Novergicus. The animals have been divided in two groups, according to the follow-up time (12 and 24 weeks and pursuant to the for form of laser application (continuous or two-point. A Holmium laser (pulsed, solid state, 2.1 micron waves, 40 watts, OmniTip 30º tip apparatus was used. After the animals were sacrificed, the proximal and distal length and width of the operated size of such rats were compared to those of the non-operated size be means of non-parametric testing (considering p=0,05. The length in the operated size was significantly bigger for both follow-up groups, when compared to the length of the non-operated size, however there was no significant difference in such measures in function of the type of laser application. In the same manner, the width, both in the proximal and distal regions, was significantly bigger in the operated size in both follow-up groups, without showing any significant difference whatsoever in function of the type of application. When the measures in both follow-up groups were compared, distal length and width showed a trend to become bigger after 24 weeks, while width in the proximal region was significantly bigger in this group. As for the subjective microscopic evaluation, both in longitudinal and cross sections, it was possible to observe and increase in the number of fibroblasts, mainly in the 12-week group. The average fibroblast concentration in the tendon with 24-week follow-up was group deemed to be intermediate between the 12-week group and non-operated tendon. The conjunctive tissue was exuberant in the region

  9. Evaluation of holmium laser versus cold knife in optical internal urethrotomy for the management of short segment urethral stricture.

    Science.gov (United States)

    Jain, Sudhir Kumar; Kaza, Ram Chandra Murthy; Singh, Bipin Kumar

    2014-10-01

    SACHSE COLD KNIFE IS CONVENTIONALLY USED FOR OPTICAL INTERNAL URETHROTOMY INTENDED TO MANAGE URETHRAL STRICTURES AND HO: YAG laser is an alternative to it. The aim of this study was to evaluate the role of urethral stricture treatment outcomes, efficacy, and complications using cold knife and Ho: YAG (Holmium laser) for optical internal urethrotomy. In this prospective study included, 90 male patients age >18 years, with diagnosis of urethral stricture admitted for internal optical urethrotomy during April 2010 to March 2012. The patients were randomized into two groups containing 45 patients each using computer generated random number. In group A (Holmium group), internal urethrotomy was done with Holmium laser and in group B (Cold knife group) Sachse cold knife was used. Patients were followed up for 6 months after surgery in Out Patient Department on 15, 30 and 180 post-operative days. At each follow up visit physical examination, and uroflowmetry was performed along with noting complaints, if any. The peak flow rates (PFR) were compared between the two groups on each follow up. At 180 days (6 month interval) the difference between mean of PFR for Holmium and Cold knife group was statistically highly significant (P knife urethrotomy.

  10. Magnetic structure of holmium-yttrium superlattices

    DEFF Research Database (Denmark)

    Jehan, D.A.; McMorrow, D.F.; Cowley, R.A.

    1993-01-01

    We present the results of a study of the chemical and magnetic structures of a series of holmium-yttrium superlattices and a 5000 angstrom film of holmium, all grown by molecular-beam epitaxy. By combining the results of high-resolution x-ray diffraction with detailed modeling, we show...... that the superlattices have high crystallographic integrity: the structural coherence length parallel to the growth direction is typically almost-equal-to 2000 angstrom, while the interfaces between the two elements are well defined and extend over approximately four lattice planes. The magnetic structures were...... determined using neutron-scattering techniques. The moments on the Ho3+ ions in the superlattices form a basal-plane helix. From an analysis of the superlattice structure factors of the primary magnetic satellites, we are able to determine separately the contributions made by the holmium and yttrium...

  11. Metrological traceability of holmium oxide solution

    Science.gov (United States)

    Gonçalves, D. E. F.; Gomes, J. F. S.; Alvarenga, A. P. D.; Borges, P. P.; Araujo, T. O.

    2018-03-01

    Holmium oxide solution was prepared as a candidate of certified reference material for spectrophotometer wavelength scale calibration. Here is presented the necessary steps for evaluation of the uncertainty and the establishment of metrological traceability for the production of this material. Preliminary results from the first produced batch are shown.

  12. Rail inspection using noncontact laser ultrasonics

    International Nuclear Information System (INIS)

    Kim, Nak Hyeon; Sohn, Hoon; Han, Soon Woo

    2012-01-01

    In this study, a noncontact laser ultrasonic system is proposed for rail defect detection. An Nd Yag pulse laser is used for generation of ultrasonic waves, and the corresponding ultrasonic responses are measured by a laser Doppler vibrometer. For the detection of rail surface damages, the shape of the excitation laser beam is transformed into a line. On the other hand, a point source laser beam is used for the inspection of defects inside a rail head. Then, the interactions of propagating ultrasonic waves with defects are examined using actual rail specimens. Amplitude attenuation was mainly observed for a surface crack, and reflections were most noticeable from an internal damage. Finally, opportunities and challenges associated with real time rail inspection from a high speed train are discussed

  13. Magnetodielectric coupling in multiferroic holmium iron garnets

    International Nuclear Information System (INIS)

    Malar Selvi, M.; Chakraborty, Deepannita; Venkateswaran, C.

    2017-01-01

    Single phase magneto-electric multiferroics require a large magnetic or electric field for producing magneto-electric (ME) and magnetodielectric (MD) effects. For utilizing these effects in devices investigations on the room temperature and low field MD studies are necessary. Recently, efforts have been largely devoted to the investigation of rare earth iron garnets. In the physical method, the preparation of rare earth iron garnet requires high sintering temperature and processing time. To solve these problems, ball milling assisted microwave sintering technique is used to prepare nanocrystalline holmium iron garnets (Ho_3Fe_5O_1_2). Magnetic and dielectric properties of the prepared sample are investigated. These properties get enhanced in nanocrystalline form when compared to the bulk. The MD coupling of the prepared sample is evident from the anomaly in the temperature dependent dielectric constant plot and the ME coupling susceptibility is derived from the room temperature MD measurements. - Highlights: • Formation of single phase Holmium iron garnet reported. • Ball milling assisted microwave sintering reduces the sintering temperature and time. • Holmium iron garnet shows enhanced magnetic and dielectric properties. • Pyromagnetic and pyroelectric measurements confirm the magnetoelectric coupling. • Room temperature magnetodielectric measurements show the nonlinear behaviour.

  14. Holmium laser lithotripsy (HoLL) of ureteral calculi

    Science.gov (United States)

    Kuntz, Rainer M.; Lehrich, Karin; Fayad, Amr

    2001-05-01

    The effectiveness and side effects of ureteroscopic HoLL of ureteral stones should be evaluated. In 63 patients (17 female, 46 males) a total of 75 stones of 3-20 mm diameter were treated with ureteroscopic HoLL. 18.7 percent of stones were located in the proximal third, 24.0 percent in the middle third and 57.3 percent in the distal third of the ureter. HoLL was performed with small diameter semirigid and flexible ureteroscopes, 220 or 365 nm flexible laser fibers and a holmium:YAG laser at a power of 5-15 W (0.5-1.0 J, 10- 15 Hz). 47 of 63 patients (74.6 percent) were immediately free of stones, and 8 others (12.6 percent) lost their residual fragments spontaneously within two weeks. Another 2 patients received additional chmolitholysis for uric acid stone fragments, i.e. 90.5 percent of patients were stone free by one sitting of ureterscopic HoLL. Of the remaining 6 patients (9.5 percent) who still had residual calculi 4 weeks after HoLL, 2 asymptomatic patients refused any additional treatment, 2 patients preferred treatment with ESWL, and 2 patients had a successful second HoLL, thereby raising the success rate of ureteroscopic HoLL to 93.7 percent. 2 patients showed contrast medium extravasation on retrograde ureterograms, due to guide wire perforation. No ureteral stricture occurred. In conclusion, transurethral ureteroscopic HoLL proved to be a safe and successful minimal invasive treatment of ureteral calculi.

  15. Ethanolamine derivatives of dysprosium and holmium

    International Nuclear Information System (INIS)

    Gharia, K.S.; Singh, M.; Mathur, S.; Sankhla, B.S.

    1981-01-01

    The preparation and properties of dysprosium and holmium derivatives of mono-, di- and tri-ethanolamine derivatives are described. Compounds of general formulae: Ln(OPrsup(i)) 2 (mea), Ln(OPrsup(i))(mea) 2 , Ln(mea) 3 , Ln(OPrsup(i))(dea), Ln 2 (dea) 3 , Ln(dea)(deaH) and Ln(tea) (where Ln = Dy or Ho and mea, dea and tea are the anions of respective ethanolamine) were obtained and characterized by elemental analysis and IR spectra. (author)

  16. Non-contact ultrasound techniques

    International Nuclear Information System (INIS)

    Khazali Mohd Zin

    2001-01-01

    Non-contact ultrasound plays significant role in material characterisation and inspection. Unlike conventional ultrasonic techniques, non-contact ultrasonic is mostly applicable to areas where the former has its weaknesses and limitations. It is interesting to note that the non-contact ultrasonic technique has an important significant application in industry. The technique is signified by the fact that the object to be inspected is further away from the ultrasonic source, no couplant is needed and inconsistent pressure between the transducer and the specimen can be eliminated. The paper discusses some of the non-contact ultrasound technique and its applications. (Author)

  17. A cladding-pumped, tunable holmium doped fiber laser.

    Science.gov (United States)

    Simakov, Nikita; Hemming, Alexander; Clarkson, W Andrew; Haub, John; Carter, Adrian

    2013-11-18

    We present a tunable, high power cladding-pumped holmium doped fiber laser. The laser generated >15 W CW average power across a wavelength range of 2.043 - 2.171 μm, with a maximum output power of 29.7 W at 2.120 μm. The laser also produced 18.2 W when operating at 2.171 µm. To the best of our knowledge this is the highest power operation of a holmium doped laser at a wavelength >2.15 µm. We discuss the significance of background losses and fiber design for achieving efficient operation in holmium doped fibers.

  18. Holmium laser enucleation of the prostate hyperplasia: technical aspects

    Directory of Open Access Journals (Sweden)

    P. V. Glybochko

    2015-01-01

    Full Text Available Holmium laser enucleation of the prostate (HoLEP was first described by doctor P.J. Gilling et al. from New Zealand in 1996. The operation involves anatomical dissection of the prostatic tissue off the surgical capsule using a high-powered holmium laser followed by intravesical morsellation. The objective of this article is to explain the techniques for HoLEP.

  19. Noncontact spirometry with a webcam

    Science.gov (United States)

    Liu, Chenbin; Yang, Yuting; Tsow, Francis; Shao, Dangdang; Tao, Nongjian

    2017-05-01

    We present an imaging-based method for noncontact spirometry. The method tracks the subtle respiratory-induced shoulder movement of a subject, builds a calibration curve, and determines the flow-volume spirometry curve and vital respiratory parameters, including forced expiratory volume in the first second, forced vital capacity, and peak expiratory flow rate. We validate the accuracy of the method by comparing the data with those simultaneously recorded with a gold standard reference method and examine the reliability of the noncontact spirometry with a pilot study including 16 subjects. This work demonstrates that the noncontact method can provide accurate and reliable spirometry tests with a webcam. Compared to the traditional spirometers, the present noncontact spirometry does not require using a spirometer, breathing into a mouthpiece, or wearing a nose clip, thus making spirometry test more easily accessible for the growing population of asthma and chronic obstructive pulmonary diseases.

  20. Crystal structure and phase composition of aluminium thin films with holmium additions

    International Nuclear Information System (INIS)

    Koleshko, V.M.; Belitskij, V.F.; Obukhov, V.E.; Rumak, N.V.; Urban, T.P.

    1984-01-01

    The effect of holmium additions on the crystal structure and phase composition of thin aluminium films has been studied. A regularity in grain size changes in aluminium thin films versus the holmium content in them is established. The holmium introduction is shown to result in the appearance of axial texture in the aluminium films, the texture axis being determined by the quantity of the addition. During heat treatment of the aluminium films, containing holmium additions, in the range of low ( approximately 100-200 deg C) annealing temperatures holmium monohydroxide is formed, and at annealing temperatures 300 deg C 0 3 is formed

  1. ANTIBACTERIAL PROPERTIES OF HOLMIUM TO CAUSATIVE AGENTS OF SUPPURATIVE -INFLAMMATORY COMPLICATIONS IN PATIENTS WITH TRAUMA

    Directory of Open Access Journals (Sweden)

    Poddubnaya H. N.

    2012-06-01

    Full Text Available Article denotes to determination of antibacterial action of polyoxometalate holmium to causative agents of suppurative-inflammatory process in wounds of patients, which were suffered from trauma. Method of serial dilutions was used for determination of minimal inhibiting concentration (MIC of holmium to staphylococci, enterococci and E. coli. Registration of holmium action shows the strong antibacterial influence to staphylococci and enterococci (MIC of holmium action to staphylococcal and enterococcal strains same 1 10 M, to strains of E.coli – 2,5 10 M. Solutions of holmium don’t have antibacterial action to strains of E.coli.

  2. Magnetoresistance in terbium and holmium single crystals

    International Nuclear Information System (INIS)

    Singh, R.L.; Jericho, M.H.; Geldart, D.J.W.

    1976-01-01

    The longitudinal magnetoresistance of single crystals of terbium and holmium metals in their low-temperature ferromagnetic phase has been investigated in magnetic fields up to 80 kOe. Typical magnetoresistance isotherms exhibit a minimum which increases in depth and moves to higher fields as the temperature increases. The magnetoresistance around 1 0 K, where inelastic scattering is negligible, has been interpreted as the sum of a negative contribution due to changes in the domain structure and a positive contribution due to normal magnetoresistance. At higher temperatures, a phenomenological approach has been developed to extract the inelastic phonon and spin-wave components from the total measured magnetoresistance. In the temperature range 4--20 0 K (approximately), the phonon resistivity varies as T 3 . 7 for all samples. Approximate upper and lower bounds have been placed on the spin-wave resistivity which is also found to be described by a simple power law in this temperature range. The implications of this result for theoretical treatments of spin-wave resistivity due to s-f exchange interactions are considered. It is concluded that the role played by the magnon energy gap is far less transparent than previously suggested

  3. Thermal property of holmium doped lithium lead borate glasses

    Science.gov (United States)

    Usharani, V. L.; Eraiah, B.

    2018-04-01

    The new glass system of holmium doped lithium lead borate glasses were prepared by conventional melt quenching technique. The thermal stability of the different compositions of Ho3+ ions doped lithium lead borate glasses were studied by using TG-DTA. The Tg values are ranging from 439 to 444 °C with respect to the holmium concentration. Physical parameters like polaron radius(rp), inter-nuclear distance (ri), field strength (F) and polarizability (αm) of oxide ions were calculated using appropriate formulae.

  4. SEM evaluation of the morphological changes in hard dental tissues prepared by Er: YAG laser and rotary instruments

    Directory of Open Access Journals (Sweden)

    Tomov Georgi

    2010-09-01

    Full Text Available Effective ablation of dental hard tissues by means of the erbium:yttrium-aluminum garnet (Er: YAG laser has been reported recently, and its application to caries removal and cavity preparation has been expected. However, few studies have investigated the morphological changes in hard dental tissues after Er: YAG laser caries treatment. In the present study the morphological changes in hard dental tissues after Er: YAG laser caries ablation in vitro was compared with that of conventional mechanical treatment. Thirty extracted human teeth with caries were used. Ten tooth was treated with the Er: YAG laser, and the other was treated with a conventional steel and diamond burs. Laser treatment was performed by means of a non-contact irradiation modes with cooling water spray, with a new Er: YAG laser (LiteTouch. Conventional bur treatment was conducted by means of a low-speed micromotor and air turbine with water cooling. Scanning electron microscope (SEM observations were performed for each treatment. The Er: YAG laser ablated carious dentin effectively with minimal thermal damage to the surrounding intact dentin, and removed infected and softened carious dentin to the same degree as the burtreatment. In addition, a lower degree of vibration was noted with the Er: YAG laser treatment. The SEM examination revealed characteristic micro-irregularities of the lased dentin and enamel surfaces with potential benefits for adhesive restorations. Our results show that the Er: YAG laser is promising as a new technical modality for caries treatment

  5. Assiut Experience in the Application of Holmium Laser in Treatment ...

    African Journals Online (AJOL)

    Assiut Experience in the Application of Holmium Laser in Treatment of Ureteral Calculi in Adults. A.M. Abdel Lateef, A.E. Abdel Moniem, M.I. Taha, M.A. Shalaby. Abstract. Internal Optical Urethrotomy at the National Medical Center of Sanou Souro in Bobo-Dioulasso: Feasibility, Safety and Short-Term Results Objective To ...

  6. Microspheres with Ultrahigh Holmium Content for Radioablation of Malignancies

    NARCIS (Netherlands)

    Bult, W.; Seevinck, P.R.; Krijger, G.C.; Visser, T.; Kroon-Batenburg, L.M.J.; Bakker, C.J.G.; Hennink, W.E.; van het Schip, A.D.; Nijsen, J.F.W.

    2009-01-01

    The aim of this study was to develop microspheres with an ultra high holmium content which can be neutron activated for radioablation of malignancies. These microspheres are proposed to be delivered selectively through either intratumoral injections into solid tumors or administered via an

  7. Microspheres with ultrahigh holmium content for radioablation of malignancies

    NARCIS (Netherlands)

    Bult, W; Seevinck, P R; Krijger, G C; Visser, T; Kroon-Batenburg, L M J; Bakker, C J G; Hennink, W E; van het Schip, A D; Nijsen, J F W

    PURPOSE: The aim of this study was to develop microspheres with an ultra high holmium content which can be neutron activated for radioablation of malignancies. These microspheres are proposed to be delivered selectively through either intratumoral injections into solid tumors or administered via an

  8. Microspheres with Ultrahigh Holmium Content for Radioablation of Malignancies

    NARCIS (Netherlands)

    Bult, W.; Seevinck, P.R.; Krijger, G.C.; Visser, T.; Kroon-Batenburg, L.M.J.; Bakker, C.J.G.; Hennink, W.E.; Van het Schip, A.D.; Nijsen, J.F.W.

    Purpose The aim of this study was to develop microspheres with an ultra high holmium content which can be neutron activated for radioablation of malignancies. These microspheres are proposed to be delivered selectively through either intratumoral injections into solid tumors or administered via an

  9. Compact high-field superconducting quadrupole magnet with holmium poles

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, D.B.; Kraus, R.H. Jr.; Lobb, C.T.; Menzel, M.T. (Los Alamos National Lab., NM (United States)); Walstrom, P.L. (Grumman Space Systems, Los Alamos, NM (United States))

    1992-03-15

    A compact high-field superconducting quadrupole magnet was designed and built with poles made of the rare-earth metal holmium. The magnet is intended for use in superconducting coupled-cavity linear accelerators where compact high-field quadrupoles are needed, but where the use of permanent magnets is ruled out because of trapped-flux losses. The magnet has a clear bore diameter of 1.8 cm, outside diameter of 11 cm, length of 11 cm, and pole tip length of 6 cm. The effect of using holmium, a material with a higher saturation field than iron, was investigated by replacing poles made of iron with identical poles made of holmium. The magnet was operated at a temperature of 4.2 K and reached a peak quadrupole field gradient of 355 T/m, a 10% increase over the same magnet with iron poles. This increase in performance is consistent with calculations based on B-H curves that were measured for holmium at 4.2 K. (orig.).

  10. Determinants of holmium:yttrium-aluminum-garnet laser time and energy during ureteroscopic laser lithotripsy.

    Science.gov (United States)

    Molina, Wilson R; Marchini, Giovanni S; Pompeo, Alexandre; Sehrt, David; Kim, Fernando J; Monga, Manoj

    2014-04-01

    To evaluate the association of preoperative noncontrast computed tomography stone characteristics, laser settings, and stone composition with cumulative holmium:yttrium-aluminum-garnet (Ho:YAG) laser time/energy. We retrospectively reviewed patients who underwent semirigid/flexible ureteroscopy and Ho:YAG laser lithotripsy (200 or 365 μm laser fiber; 0.8-1.0 J energy; and 8-10 Hz rate) at 2 tertiary care centers (April 2010-May 2012). Studied parameters were as follows: patient's characteristics; stone characteristics (location, burden, hardness, and composition); total laser time and energy; and surgical outcomes. One hundred patients met our inclusion criteria. Mean stone size was 1.01 ± 0.42 cm and volume 0.33 ± 0.04 cm(3). Mean stone radiodensity was 990 ± 296 HU, and Hounsfield units density 13.8 ± 6.0 HU/mm. All patients were considered stone free. Stone size and volume had a significant positive correlation with laser energy (R = 0.516, P R = 0.621, P R = 0.477, P R = 0.567, P stone size, only the correlation between HU and laser time was significant (R = 0.262, P = .011). In the multivariate analysis, with exception of stone composition (P = .103), all parameters significantly increased laser energy (R(2) = 0.524). Multivariate analysis revealed a positive significant association of laser time with stone volume (P R(2) = 0.512). In multivariate analysis for laser energy, only calcium phosphate stones required less energy to fragment compared with uric acid stones. No significant differences were found in the multivariate laser time model. Ho:YAG laser cumulative energy and total time are significantly affected by stone dimensions, hardness location, fiber size, and power. Kidney location, laser fiber size, and laser power have more influence on the final laser energy than on the total laser time. Calcium phosphate stones require less laser energy to fragment. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Noncontacting-optical-strain device

    Science.gov (United States)

    Silver, R. H.

    1970-01-01

    Noncontacting-strain-measuring gauge and extensometer remotely measures the mechanical displacement along the entire length of a test specimen. Measurement is accomplished by continuous scanning of a reflected light from reflective bench markings or stripes previously affixed to the specimen.

  12. PREFACE: Non-contact AFM Non-contact AFM

    Science.gov (United States)

    Giessibl, Franz J.; Morita, Seizo

    2012-02-01

    This special issue is focussed on high resolution non-contact atomic force microscopy (AFM). Non-contact atomic force microscopy was established approximately 15 years ago as a tool to image conducting and insulating surfaces with atomic resolution. Since 1998, an annual international conference has taken place, and although the proceedings of these conferences are a useful source of information, several key developments warrant devoting a special issue to this subject. In the theoretic field, the possibility of supplementing established techniques such as scanning tunneling microscopy (STM) and Kelvin probe microscopy with atomically resolved force micrsoscopy poses many challenges in the calculation of contrast and contrast reversal. The surface science of insulators, self-assembled monolayers and adsorbates on insulators is a fruitful field for the application of non-contact AFM: several articles in this issue are devoted to these subjects. Atomic imaging and manipulation have been pioneered using STM, but because AFM allows the measurement of forces, AFM has had a profound impact in this field as well. Three-dimensional force spectroscopy has allowed many important insights into surface science. In this issue a combined 3D tunneling and force microscopy is introduced. Non-contact AFM typically uses frequency modulation to measure force gradients and was initially used mainly in a vacuum. As can be seen in this issue, frequency modulation is now also used in ambient conditions, allowing better spatial and force resolution. We thank all of the contributors for their time and efforts in making this special issue possible. We are also very grateful to the staff of IOP Publishing for handling the administrative aspects and for steering the refereeing process. Non-contact AFM contents Relation between the chemical force and the tunnelling current in atomic point contacts: a simple model Pavel Jelínek, Martin Ondrácek and Fernando Flores Theoretical simulation of

  13. Drug metabolism: Comparison of biodistribution profile of holmium in three different compositions in healthy Wistar rats

    International Nuclear Information System (INIS)

    Cerqueira-Coutinho, Cristal; Vidal, Lluis Pascual; Pinto, Suyene Rocha; Santos-Oliveira, Ralph

    2016-01-01

    Radioisotope holmium is a candidate to be used in cancer treatment and diagnosis. There are different holmium salts and they present distinct solubility and consequently different biodistribution profiles. In this work, we aimed to evaluate the biodistribution profiles of two holmium salts (chloride and sulfate) and holmium nanoparticles (oxide) through an in vivo biodistribution assay using animal model. Samples were labeled with technetium-99m and administered in Wistar rats by retro-orbital route. Holmium chloride is highly soluble in water and it was quickly filtered by the kidneys while holmium sulfate that presents lower solubility in water was mainly found in the liver and the spleen. However, both the salts showed a similar biodistribution profile. On the other hand, holmium oxide showed a very different biodistribution profile since it seemed to interact with all organs. Due to its particle size range (approximately 100 nm) it was not intensively filtered by the kidneys being found in high quantities in many organs, for this reason its use as a nanoradiopharmaceutical could be promising in the oncology field. - Highlights: • This article brings the biodistribution of holmium in 3 different compositions. • The results, as a technical note may help other researchers around the world to elucidate the mechanism (biological behavior) and the best strategy to use holmium as radiopharmaceutical.

  14. Tape casting fabrication and properties of planar waveguide YAG/Yb:YAG/YAG transparent ceramics

    Science.gov (United States)

    Zhao, Yu; Liu, Qiang; Ge, Lin; Wang, Chao; Li, Wenxue; Yang, Chao; Wang, Juntao; Yuan, Lei; Xie, Tengfei; Kou, Huamin; Pan, Yubai; Gao, Qingsong; Bo, Yong; Peng, Qinjun; Xu, Zuyan; Li, Jiang

    2017-07-01

    Highly transparent YAG/10at.%Yb:YAG/YAG planar waveguide ceramics were fabricated by the non-aqueous tape casting and solid-state reactive sintering technology. The tapes are relatively homogeneous and the green body shows a dense structure without distinct interfaces after the treatment of debinding and cold isostatic pressing. YAG/10at.%Yb:YAG/YAG ceramics with almost full dense structure were obtained by vacuum-sintering at 1760 °C for 30 h. For the mirror-polished sample with the thickness of 3.5 mm, the In-line transmittance was measured to be 83.6% at the visual wavelength of 400 nm. The diffusion distance of the Yb3+ ions was about 215 μm along the thickness direction of the ceramics. In the lasing experiments, the YAG/10at.%Yb:YAG/YAG planar waveguide ceramics were end-pumped by a 976 nm semiconductor diode laser and enabled efficient continuous-wave lasers, which resulted in a maximum output power of 1.6 W and a slope efficiency of 34.4% at 1030 nm.

  15. Noncontacting Optical Measurement And Inspection Systems

    Science.gov (United States)

    Asher, Jeffrey A.; Jackson, Robert L.

    1986-10-01

    Product inspection continues to play a growing role in the improvement of quality and reduction of scrap. Recent emphasis on precision measurements and in-process inspection have been a driving force for the development of noncontacting sensors. Noncontacting sensors can provide long term, unattended use due to the lack of sensor wear. Further, in applications where, sensor contact can damage or geometrically change the part to be measured or inspected, noncontacting sensors are the only technical approach available. MTI is involved in the development and sale of noncontacting sensors and custom inspection systems. This paper will review the recent advances in noncontacting sensor development. Machine vision and fiber optics sensor systems are finding a wide variety of industrial inspection applications. This paper will provide detailed examples of several state-of-the-art applications for these noncontacting sensors.

  16. Acupoint Massage in Relieving Pain after Ureteroscopic Holmium Laser Lithotripsy

    Institute of Scientific and Technical Information of China (English)

    Xia Wei-qin

    2014-01-01

    Objective: To observe the effect of acupoint massage in relieving pain after ureteroscopic holmium laser lithotripsy. Methods: Ninety-two patients undergone ureteroscopic holmium laser lithotripsy were enrolled and randomized into a treatment group and a control group, 46 in each group. Patients in the control group were given regular nursing care, while patients in the treatment group were intervened by acupoint massage in addition to the regular nursing care. The pain was evaluated by visual analogue scale (VAS) at 6 h, 12 h, and 24 h after operation, and compared between the two groups. Results:There was no significant difference in comparing the VAS score at 6 h after operation between the two groups (P>0.05). The VAS scores in the treatment group at 12 h and 24 h after operation were significantly lower than those in the control group (both P Conclusion: Acupoint massage can effectively relieve the pain after ureteroscopic holmium laser lithotripsy, reduce the use of analgesics, and promote the recovery.

  17. Synthesis and ultrasonic characterisation of vitreous holmium phosphates

    International Nuclear Information System (INIS)

    Senin Hassan; Sidek Hj, Abdul Aziz; Abdul Halim Shaari

    1996-01-01

    The ultrasonic properties of holmium metaphosphate glasses (Ho sub 2 O sub 3) sub x (P sub 2 O sub 5) sub 1-x, with the mole fraction of x of holmium oxide equal to 0.208, 0.22 and 0.231 respectively, have been determined from measurements of the effects of temperature and hydrostatic pressure on ultrasonic wave velocities. At temperature below about 100K, the ultrasonic wave velocity of this type of rare earth phosphate glasses become anomalously dependent upon temperature; a behaviour associated with the interaction between acoustic phonons and two level systems. The hydrostatic pressure derivatives (∂ C sup S sub IJ / ∂ P) sub p=0 of the elastic stiffnesses C sub IJ and also (∂ C sup S sub IJ / ∂ P) sub p=0 of the bulk modulus B sup S of these glasses are anomalously negative. Both longitudinal γ sub L and shear γ sub S acoustic mode Gruneisen parameters are small and negative : the application of pressure softens the long-wavelength acoustic phonon mode frequencies. The results confirmed that the holmium phosphate glasses show an extraordinary elastic behaviour under high pressures

  18. Dysprosium (holmium) determination in the presence of erbium and dysprosium (holmium, erbium) determination in the presence of cerium

    International Nuclear Information System (INIS)

    Tolubara, A.I.; Kochubej, A.I.; Usatenko, Yu.I.

    1978-01-01

    Effect of salicylic acid upon complex formation in the systems REE - boronsulfoalizarinate, REE - oxine and REE - boronsulfoalizarinate - oxine is investigated. Comparison of optical characteristics of the above systems in the absence and in the presence of salicylic acid is carried out. It is established that in all the cases the effect of salicylic acid depends both on the nature of REE and the ratio of all the components of the system. Under certain conditions the given dependence is observed only for erbium complexes. Extraction-photometric methods of dysprosium and holmium determination in the presence of equal erbium amounts, as well as holmium and erbium determination in the presence of cerium equal amounts is developed

  19. Dysprosium (holmium) determination in the presence of erbium and dysprosium (holmium, erbium) determination in the presence of cerium

    Energy Technology Data Exchange (ETDEWEB)

    Tolubara, A I; Kochubei, A I; Usatenko, Yu I

    1978-01-01

    Effect of salicylic acid upon complex formation in the systems REE - boronsulfoalizarinate, REE - oxine and REE - boronsulfoalizarinate - oxine is investigated. Comparison of optical characteristics of the above systems in the absence and in the presence of salicylic acid is carried out. It is established that in all the cases the effect of salicylic acid depends both on the nature of REE and the ratio of all the components of the system. Under certain conditions the given dependence is observed only for erbium complexes. Extraction-photometric methods of dysprosium and holmium determination in the presence of equal erbium amounts, as well as holmium and erbium determination in the presence of cerium equal amounts is developed.

  20. Nd:YAG laser therapy for rectal and vaginal venous malformations.

    Science.gov (United States)

    Gurien, Lori A; Jackson, Richard J; Kiser, Michelle M; Richter, Gresham T

    2017-08-01

    Limited therapeutic options exist for rectal and vaginal venous malformations (VM). We describe our center's experience using Nd:YAG laser for targeted ablation of abnormal veins to treat mucosally involved pelvic VM. Records of patients undergoing non-contact Nd:YAG laser therapy of pelvic VM at a tertiary children's hospital were reviewed. Symptoms, operative findings and details, complications, and outcomes were evaluated. Nine patients (age 0-24) underwent Nd:YAG laser therapy of rectal and/or vaginal VM. Rectal bleeding was present in all patients and vaginal bleeding in all females (n = 5). 5/7 patients had extensive pelvic involvement on MRI. Typical settings were 30 (rectum) and 20-25 W (vagina), with 0.5-1.0 s pulse duration. Patients underwent the same-day discharge. Treatment intervals ranged from 14 to 180 (average = 56) weeks, with 6.1-year mean follow-up. Five patients experienced symptom relief with a single treatment. Serial treatments managed recurrent bleeding successfully in all patients, with complete resolution of vaginal lesions in 40% of cases. No complications occurred. Nd:YAG laser treatment of rectal and vaginal VM results in substantial improvement and symptom control, with low complication risk. Given the high morbidity of surgical resection, Nd:YAG laser treatment of pelvic VM should be considered as first line therapy.

  1. Microspheres with an ultra high holmium content for brachytherapy of malignancies

    International Nuclear Information System (INIS)

    Lira, Raphael A.; Myamoto, Douglas M.; Souza, Jaime R.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de; Osso Junior, Joao A.; Martinelli, Jose R.

    2011-01-01

    The overall objective of this work is to develop biodegradable microspheres intended for internal radiation therapy which provides an improved treatment for hepatic carcinomas. The most studied brachytherapy system employing microspheres made of holmium-biopolymer system is composed by poly(L-lactic acid) (PLLA) and holmium acetylacetonate (HoAcAc). The importance of the holmium high content in the microspheres can be interpreted as follow from a therapeutic standpoint, to achieve an effective use of microspheres loaded with HoAcAc, a high content of holmium is required to yield enough radioactivity with a relatively low amount of microspheres.The usual amounts of holmium that are incorporated in the microspheres composed by poly(L-lactic acid) and HoAcAc are 17.0 ± 0.5% (w/w) of holmium, which corresponds to a loading of about 50% of HoAcAc. Different approaches have been investigated to increase that value. One updated approach towards this direction is the production of microspheres with ultrahigh holmium as matrix using HoAcAc crystals as the sole starting material without the use of biopolymer. Likewise, in the search of microspheres with increased holmium content , it has been demonstrated that by changing the HoAcAc crystal structure by its recrystallization from crystal phase to the amorphous there is lost of acetylacetonate and water molecules causing the increasing of the holmium content. Microspheres were prepared by solvent evaporation, using holmium acetylacetonate (HoAcAc) crystals as the sole ingredient. Microspheres were characterized by using light and scanning electron microscopy, infrared and Raman spectroscopy, differential scanning calorimetry, X-rays diffraction, and confocal laser scanning microscopy. (author)

  2. Microspheres with an ultra high holmium content for brachytherapy of malignancies

    Energy Technology Data Exchange (ETDEWEB)

    Lira, Raphael A.; Myamoto, Douglas M.; Souza, Jaime R.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Biotecnologia; Osso Junior, Joao A. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Radiofarmacia; Martinelli, Jose R. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Ciencias e Tecnologia de Materiais

    2011-07-01

    The overall objective of this work is to develop biodegradable microspheres intended for internal radiation therapy which provides an improved treatment for hepatic carcinomas. The most studied brachytherapy system employing microspheres made of holmium-biopolymer system is composed by poly(L-lactic acid) (PLLA) and holmium acetylacetonate (HoAcAc). The importance of the holmium high content in the microspheres can be interpreted as follow from a therapeutic standpoint, to achieve an effective use of microspheres loaded with HoAcAc, a high content of holmium is required to yield enough radioactivity with a relatively low amount of microspheres.The usual amounts of holmium that are incorporated in the microspheres composed by poly(L-lactic acid) and HoAcAc are 17.0 {+-} 0.5% (w/w) of holmium, which corresponds to a loading of about 50% of HoAcAc. Different approaches have been investigated to increase that value. One updated approach towards this direction is the production of microspheres with ultrahigh holmium as matrix using HoAcAc crystals as the sole starting material without the use of biopolymer. Likewise, in the search of microspheres with increased holmium content , it has been demonstrated that by changing the HoAcAc crystal structure by its recrystallization from crystal phase to the amorphous there is lost of acetylacetonate and water molecules causing the increasing of the holmium content. Microspheres were prepared by solvent evaporation, using holmium acetylacetonate (HoAcAc) crystals as the sole ingredient. Microspheres were characterized by using light and scanning electron microscopy, infrared and Raman spectroscopy, differential scanning calorimetry, X-rays diffraction, and confocal laser scanning microscopy. (author)

  3. CLINICAL-EVALUATION OF 2 NONCONTACT TONOMETERS

    NARCIS (Netherlands)

    KOOPMANS, SA; KOOIJMAN, AC; VANRIJ, G; EISSES, J; DEGROOTWOLTJER, J

    1991-01-01

    The precision and speed of two non-contact tonometers were examined and compared. The Goldmann applanation tonometer was used as the standard for precision. On the average the results obtained with the non-contact tonometers were not significantly different from those obtained with the Goldmann

  4. Effect of laser peripheral iridotomy using argon and neodymium-YAG lasers on corneal endothelial cell density: 7-year longitudinal evaluation.

    Science.gov (United States)

    Ono, Takashi; Iida, Masaharu; Sakisaka, Toshihiro; Minami, Keiichiro; Miyata, Kazunori

    2018-03-01

    To evaluate the changes in corneal endothelial cell density (ECD) over a 7-year period after laser peripheral iridotomy (LPI) using argon and neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers. Retrospective case series. Eyes that underwent prophylactic LPI using argon and Nd:YAG lasers were followed up for 7 years. Central corneal endothelial cells were observed by use of noncontact specular microscopy preoperatively and at 1 and 7 years postoperatively. Changes in ECD and the associations between preoperative ECD and the total energy of the Nd:YAG laser were evaluated. Fifty-one eyes of 51 patients were followed up for 7 years. The ECD significantly decreased after LPI (P laser energy. Long-term evaluation indicated that the reduction in ECD after argon-Nd:YAG laser LPI was present but small during the initial year and was negligible after 1 year.

  5. Ocular brachytherapy with a holmium-166 irradiator device

    Energy Technology Data Exchange (ETDEWEB)

    Mourao, Arnaldo P. [Centro Federal de Educacao Tecnoloica de Minas Gerais (CEFET-MG), Belo Horizonte, MG (Brazil). Nucleo de Engenharia Hospitalar], e-mail: aprata@des.cefetmg.br; Campos, Tarcisio P.R. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Programa de Pos-graduacao em Ciencias e Tecnicas Nucleares], e-mail: campos@nuclear.ufmg.br

    2009-07-01

    The ocular brachytherapy is a method that allows controlling ocular tumors. However, the irradiation of the ocular area in high doses can bring damages mainly to the surrounding healthy tissue, such as lens, retina and bone tissue of the orbital area in growth phase. Brachytherapy in comparison to teletherapy allows a large reduction of the absorbed doses in the adjacent tissues avoiding deleterious effects. Various types of radionuclides can be applied to ocular brachytherapy. Those radionuclides shall be encapsulated and placed juxtaposed to the sclera, back to the tumor. Herein, a new device was developed to encapsulate the radioactive material. It can easily place back of the eyeball. A computational model of the ocular area was developed in order to simulate the spatial dose distribution promoted by the holmium-166 nuclide distributed inside the irradiator device. The simulations addressed a device placed on the surface of the sclera, rotated 90 deg taken at the normal axis forward to the lens. The simulation was carried on the code Monte Carlo MCNP5. The computational simulation generates the spatial dose distribution in the treated volume. All continuous beta and the discrete gamma and X-ray spectra emitted by the holmium-166 were incorporated on simulations. The results allow comparing the space dose distribution to other types of sources used for the same end. The sclera absorbed dose, the maximum apical tumor dose, as well as on the tumor base were investigated. Indeed, the tumor thickness defines the conditions of irradiation. The holmium-166 dose distribution provides a tool to propose a better and optimized protocol for ocular brachytherapy. (author)

  6. Ocular brachytherapy with a holmium-166 irradiator device

    International Nuclear Information System (INIS)

    Mourao, Arnaldo P.; Campos, Tarcisio P.R.

    2009-01-01

    The ocular brachytherapy is a method that allows controlling ocular tumors. However, the irradiation of the ocular area in high doses can bring damages mainly to the surrounding healthy tissue, such as lens, retina and bone tissue of the orbital area in growth phase. Brachytherapy in comparison to teletherapy allows a large reduction of the absorbed doses in the adjacent tissues avoiding deleterious effects. Various types of radionuclides can be applied to ocular brachytherapy. Those radionuclides shall be encapsulated and placed juxtaposed to the sclera, back to the tumor. Herein, a new device was developed to encapsulate the radioactive material. It can easily place back of the eyeball. A computational model of the ocular area was developed in order to simulate the spatial dose distribution promoted by the holmium-166 nuclide distributed inside the irradiator device. The simulations addressed a device placed on the surface of the sclera, rotated 90 deg taken at the normal axis forward to the lens. The simulation was carried on the code Monte Carlo MCNP5. The computational simulation generates the spatial dose distribution in the treated volume. All continuous beta and the discrete gamma and X-ray spectra emitted by the holmium-166 were incorporated on simulations. The results allow comparing the space dose distribution to other types of sources used for the same end. The sclera absorbed dose, the maximum apical tumor dose, as well as on the tumor base were investigated. Indeed, the tumor thickness defines the conditions of irradiation. The holmium-166 dose distribution provides a tool to propose a better and optimized protocol for ocular brachytherapy. (author)

  7. Structural and optical properties of α-Fe2O3 nanoparticles, influence by holmium ions

    Science.gov (United States)

    Mathevula, L. E.; Noto, L. L.; Mothudi, B. M.; Dhlamini, M. S.

    2018-04-01

    α-Fe2O3 and α-Fe2O3 doped with different concentration of holmium ions were synthesized by a simple sol-gel method. The XRD data confirmed the hexagonal structure of α-Fe2O3 for un-doped and holmium doped samples. The crystallite size was found to be decreasing with increasing holmium concentration. The amount of holmium was quantified using an EDS, which shows an increase in holmium quantity as concentration increases. The UV-Vis measurement shows an absorption edge around 570 nm. The band gap was estimated using the Kubelka-Munk relation and it was found to be fluctuating between 1.94 eV and 2.04 eV. The PL spectra confirmed the effect of holmium ions on luminescence properties of α-Fe2O3 which showed a maximum intensity at 0.1 mol% Holmium, and quenching as the concentration is increased from 0.3 mol% to 0.9 mol%.

  8. Synthesis, Characterization and Thermal Diffusivity of Holmium and Praseodymium Zirconates

    OpenAIRE

    Stopyra M.; Niemiec D.; Moskal G.

    2016-01-01

    A2B2O7 oxides with pyrochlore or defected fluorite structure are among the most promising candidates for insulation layer material in thermal barrier coatings. The present paper presents the procedure of synthesis of holmium zirconate Ho2Zr2O7 and praseodymium zirconate Pr2Zr2O7 via Polymerized-Complex Method (PCM). Thermal analysis of precursor revealed that after calcination at relatively low temperature (700°C) fine-crystalline, single-phase material is obtained. Thermal diffusivity was me...

  9. Thermal Response to High-Power Holmium Laser Lithotripsy.

    Science.gov (United States)

    Aldoukhi, Ali H; Ghani, Khurshid R; Hall, Timothy L; Roberts, William W

    2017-12-01

    The aim of this study was to investigate "caliceal" fluid temperature changes during holmium laser activation/lithotripsy using settings up to 40 W power output with different irrigation flow rates. The experimental system consisted of a glass test tube (diameter 10 mm/length 75 mm) filled with deionized water, to mimic a calix. Real-time temperature was recorded using a thermocouple (Physitemp, NJ) positioned 5 mm from the bottom of the tube. A 200 μm laser fiber (Flexiva; Boston Scientific, MA) was introduced through the working channel of a disposable ureteroscope (LithoVue; Boston Scientific) and the laser fiber tip was positioned 15 mm above the bottom of the test tube. Deionized water irrigation (room temperature) through the working channel of the ureteroscope was delivered at flow rates of 0, 7-8, 14-15, and 38-40 mL/minute. A 120-W holmium laser (pulse 120; Lumenis, CA) was used. The following settings were explored: 0.5 J × 10 Hz, 1.0 J × 10 Hz, 0.5 J × 20 Hz, 1.0 J × 20 Hz, 0.5 J × 40 Hz, 1.0 J × 40 Hz, and 0.5 J × 80 Hz. During each experiment, the laser was activated continuously for 60 seconds. Temperature increased with increasing laser power output and decreasing irrigation flow rate. The highest temperature, 70.3°C (standard deviation 2.7), occurred with laser setting of 1.0 J × 40 Hz and no irrigation after 60 seconds of continuous laser firing. None of the tested laser settings and irrigation parameters produced temperature exceeding 51°C when activated for only 10 seconds of continuous laser firing. High-power holmium settings fired in long bursts with low irrigation flow rates can generate high fluid temperatures in a laboratory "caliceal" model. Awareness of this risk allows urologist to implement a variety of techniques (higher irrigation flow rates, intermittent laser activation, and potentially cooled irrigation fluid) to control and mitigate thermal

  10. Synthesis and Characterization of Holmium-Doped Iron Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Maarten Bloemen

    2014-02-01

    Full Text Available Rare earth atoms exhibit several interesting properties, for example, large magnetic moments and luminescence. Introducing these atoms into a different matrix can lead to a material that shows multiple interesting effects. Holmium atoms were incorporated into an iron oxide nanoparticle and the concentration of the dopant atom was changed in order to determine its influence on the host crystal. Its magnetic and magneto-optical properties were investigated by vibrating sample magnetometry and Faraday rotation measurements. The luminescent characteristics of the material, in solution and incorporated in a polymer thin film, were probed by fluorescence experiments.

  11. Holmium laser enucleation versus laparoscopic simple prostatectomy for large adenomas.

    Science.gov (United States)

    Juaneda, R; Thanigasalam, R; Rizk, J; Perrot, E; Theveniaud, P E; Baumert, H

    2016-01-01

    The aim of this study is to compare Holmium laser enucleation of the prostate with another minimally invasive technique, the laparoscopic simple prostatectomy. We compared outcomes of a series of 40 patients who underwent laparoscopic simple prostatectomy (n=20) with laser enucleation of the prostate (n=20) for large adenomas (>100 grams) at our institution. Study variables included operative time and catheterization time, hospital stay, pre- and post-operative International Prostate Symptom Score and maximum urinary flow rate, complications and economic evaluation. Statistical analyses were performed using the Student t test and Fisher test. There were no significant differences in patient age, preoperative prostatic size, operating time or specimen weight between the 2 groups. Duration of catheterization (P=.0008) and hospital stay (P.99). Holmium enucleation of the prostate has similar short term functional results and complication rates compared to laparoscopic simple prostatectomy performed in large glands with the advantage of less catheterization time, lower economic costs and a reduced hospital stay. Copyright © 2015 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  12. Dielectric and conducting behaviour of polycrystalline holmium octa-molybdate

    International Nuclear Information System (INIS)

    Want, Basharat; Zahoor Ahmad, Bhat; Hamid Bhat, Bilal

    2014-01-01

    Polycrystalline holmium octa-molybdate spherulites have been obtained by using gel diffusion technique and characterized by different physio-chemical techniques. The surfaces of these spherulites are composed of nano-rod with an average diameter of about 80 nm. At room temperature the initial crystal structure is triclinic, space group P1. Thermal studies suggested a phase transition occurring in holmium octa-molybdate crystals at about 793 K. The electrical properties of the system have been studied as a function of frequency and temperature in the ranges of 20 Hz–3 MHz and 290–570 K, respectively. A giant dielectric constant and two loss peaks have been observed in the permittivity formalism. The conducting behaviour of the material is also discussed. The conductivity was found to be 1572 μ Ω −1 m −1 at room temperature and 3 MHz frequency. The conductivity of the polycrystalline material was attributed to the fact that it arises due to the migration of defects on the oxygen sub-lattice. Impedance studies were also performed in the frequency domain to infer the bulk and grain boundary contributions to the overall electric response of the material. The electrical responses have been attributed to the grain, grain-boundary, and interfacial effects. (paper)

  13. Holmium laser use in the treatment of selected dry eye syndrome complications

    Science.gov (United States)

    Kecik, Dariusz; Kecik, Tadeusz; Kasprzak, Jan; Kecik, Mariusz

    1996-03-01

    The authors present initial results of treatment selected complications of dry eye syndrome with holmium laser. The lacrimal puncta obliteration and coagulation of the corneal ulcer surface were done.

  14. HOLMIUM LASER ENUCLEATION OF THE PROSTATE, FEATURES OF THE INTERVENTION

    Directory of Open Access Journals (Sweden)

    O. Y. Hublarov

    2014-01-01

    Full Text Available Holmium laser enucleation of the prostate (HoLEP is a minimally invasive procedure used for the treatment of benign prostatic hyperplasia. The method is as reliable performance with long-term monitoring, and high safety compared to conventional methods of surgical treatment of prostatic hyperplasia – suprapubic simple prostatectomy and transurethral resection of the prostate. Despite the complexity and duration of training for mastering HoLEP currently has a definite Frortage of references detailing the technical aspects of the method. The proposed article is detailed recommendations skilled mastering HoLEP. The material is based on a review of existing literature and my own experience and clinical material Latgale Urology Center in the development and conduct of HoLEP. 

  15. Impact of pulse duration on Ho:YAG laser lithotripsy: fragmentation and dusting performance.

    Science.gov (United States)

    Bader, Markus J; Pongratz, Thomas; Khoder, Wael; Stief, Christian G; Herrmann, Thomas; Nagele, Udo; Sroka, Ronald

    2015-04-01

    In vitro investigations of Ho:YAG laser-induced stone fragmentation were performed to identify potential impacts of different pulse durations on stone fragmentation characteristics. A Ho:YAG laser system (Swiss LaserClast, EMS S.A., Nyon, Switzerland) with selectable long or short pulse mode was tested with regard to its fragmentation and laser hardware compatibility properties. The pulse duration is depending on the specific laser parameters. Fragmentation tests (hand-held, hands-free, single-pulse-induced crater) on artificial BEGO stones were performed under reproducible experimental conditions (fibre sizes: 365 and 200 µm; laser settings: 10 W through combinations of 0.5, 1, 2 J/pulse and 20, 10, 5 Hz, respectively). Differences in fragmentation rates between the two pulse duration regimes were detected with statistical significance for defined settings. Hand-held and motivated Ho:YAG laser-assisted fragmentation of BEGO stones showed no significant difference between short pulse mode and long pulse mode, neither in fragmentation rates nor in number of fragments and fragment sizes. Similarly, the results of the hands-free fragmentation tests (with and without anti-repulsion device) showed no statistical differences between long pulse and short pulse modes. The study showed that fragmentation rates for long and short pulse durations at identical power settings remain at a comparable level. Longer holmium laser pulse duration reduces stone pushback. Therefore, longer laser pulses may result in better clinical outcome of laser lithotripsy and more convenient handling during clinical use without compromising fragmentation effectiveness.

  16. Experience with endoscopic holmium laser in the pediatric population

    Science.gov (United States)

    Merguerian, Paul A.; Reddy, Pramod P.; Barrieras, Diego; Bagli, Darius J.; McLorie, Gordon A.; Khoury, Antoine E.

    1999-06-01

    Introduction: Due to the unavailability of suitable endoscopic instruments, pediatric patients have not benefited fully from the technological advances in the endoscopic management of the upper urinary tract. This limitation may be overcome with the Holmuim:Yttrium-Aluminum-Garnet(Ho:YAG) laser delivered via small instruments. To date, there is no published report on the use of this modality in children. Purpose: We evaluated the indications, efficacy, and complications of endourological Ho:YAG laser surgery in the treatment of pediatric urolithiasis, posterior urethral valves, ureterocele and ureteropelvic junction obstruction. Methods: The patient population included 10 children with renal, ureteral and bladder calculi, 2 children with posterior urethral valves, 2 children with obstructing ureteroceles, 2 children with ureteropelvic junction obstruction and 1 child with a urethral stricture. Access to the lesions was either antegrade via a percutaneous nephrostomy tract or retrograde via the urethra. A solid state Ho:YAG laser with maximum output of 30 watts (New Star lasers, Auburn, CA) was utilized as the energy source. Results: A total of 10 patients underwent laser lithotripsy. The means age of the patients was 9 yrs (5-13 yrs). The average surface area of the calculi as 425.2 mm2 (92-1645 mm2). 8 of the patients required one procedure to render them stone free, one patient had a staghorn calculus filling every calyx of a solitary kidney requiring multiple treatments and one other patient with a staghorn calculus required 2 treatments. There were no complications related to the laser lithotripsy. Two newborn underwent successful ablation of po sterious urethral valves. Two infants underwent incision of obstructing ureteroceles with decompression of the ureterocele on postoperative ultrasound. Two children underwent endypyelotomy for ureteropelvic junction obstruction. One was successful an done required an open procedure to correct the obstruction. One child

  17. A Study on non-contact measurements of laser-generated lamb waves

    International Nuclear Information System (INIS)

    Jang, Tae Seong; Lee, Jung Ju; Lee, Seung Seok

    2002-01-01

    Generation and detection of Lamb waves offer an effective non-destructive testing technique that will detect defects quickly and reliably. Lamb waves are generated in a thin plate by Q-switched Nd:YAG pulsed laser. Symmetric and antisymmetric Lamb modes in low-frequency-thickness regime are excited by illuminating a thin plate with an array of laser-generated line sources. The propagation of laser-generated Lamb waves is detected by measuring the out-of-plane displacements in a non-contact manner using the fiber optic Sagnac interferometer and all commercial adaptive reference-beam interferometer. The characteristics of laser-generated Lamb wave due to its frequency are investigated. Fundamental understanding of laser-generated Lamb modes is presented.

  18. Holmium laser enucleation for prostate adenoma greater than 100 gm.: comparison to open prostatectomy.

    Science.gov (United States)

    Moody, J A; Lingeman, J E

    2001-02-01

    Options for treatment of large (greater than 100 gm.) prostatic adenomas have until now been limited to open surgery or transurethral resection by skilled resectionists. Considerable blood loss, morbidity, extended hospital stay and prolonged recovery occur with open surgery for large prostatic adenomas. Endoscopic surgery for benign prostatic hyperplasia has evolved during the last decade to offer the patient and surgeon significant advantages of transurethral removal of prostatic adenomas. Holmium laser enucleation of the prostate with transurethral tissue morcellation provides significant reductions in morbidity, bleeding and hospital stay for patients with large prostate adenomas. A retrospective review of data on 10 cases of holmium laser enucleation and 10 open prostatectomies for greater than 100 gm. prostatic adenomas was performed from 1998 to 1999 at our institution. Patient demographics, indication for surgery, preoperative and postoperative American Urological Association (AUA) symptom scores, operating time, serum hemoglobin, resected prostatic weight, pathological diagnosis, length of stay and complications were compared. Patient age, indications for surgery (retention, failed medical therapy, high post-void residual, bladder calculi, bladder diverticula and azotemia) and preoperative AUA symptom scores were similar in both groups. Postoperative AUA symptom scores were significantly decreased (p gm., p = 0.0003). Resected weight was greater in the holmium laser enucleation group (151 versus 106 gm., p = 0.07). Length of stay was significantly shorter in the holmium laser enucleation group (2.1 versus 6.1 days, p <0.001). Complications in the holmium laser enucleation group included stress urinary incontinence in 4 cases, prostatic perforation in 1 and urinary retention in 1. No patient treated with holmium laser enucleation was discharged home with an indwelling catheter. Complications in the open prostatectomy group included bladder neck contractures

  19. Cryogenic Yb: YAG Thin-Disk Laser

    Science.gov (United States)

    2016-09-09

    as a 4- level laser. Its absorption and emission cross-sections increase, and its thermal conductivity improves. Yb:YAG thin disk laser performance...Air Force Base, NM USA 87117 4RINI Technologies, 582 South Econ Circle, Oviedo, FL USA 32765 Keywords: Laser materials; Lasers, ytterbium...temperatures, Yb:YAG behaves as a 4- level laser. Its absorption and emission cross-sections increase, and its thermal conductivity improves. Yb:YAG

  20. Conduction and stability of holmium titanium oxide thin films grown by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Castán, H., E-mail: helena@ele.uva.es [Department of Electronic, University of Valladolid, 47011 Valladolid (Spain); García, H.; Dueñas, S.; Bailón, L. [Department of Electronic, University of Valladolid, 47011 Valladolid (Spain); Miranda, E. [Departament d' Enginyería Electrònica, Universitat Autónoma de Barcelona, 08193 Bellaterra (Spain); Kukli, K. [Department of Chemistry, University of Helsinki, FI-00014 Helsinki (Finland); Institute of Physics, University of Tartu, EE-50411,Tartu (Estonia); Kemell, M.; Ritala, M.; Leskelä, M. [Department of Chemistry, University of Helsinki, FI-00014 Helsinki (Finland)

    2015-09-30

    Holmium titanium oxide (HoTiO{sub x}) thin films of variable chemical composition grown by atomic layer deposition are studied in order to assess their suitability as dielectric materials in metal–insulator–metal electronic devices. The correlation between thermal and electrical stabilities as well as the potential usefulness of HoTiO{sub x} as a resistive switching oxide are also explored. It is shown that the layer thickness and the relative holmium content play important roles in the switching behavior of the devices. Cycled current–voltage measurements showed that the resistive switching is bipolar with a resistance window of up to five orders of magnitude. In addition, it is demonstrated that the post-breakdown current–voltage characteristics in HoTiO{sub x} are well described by a power-law model in a wide voltage and current range which extends from the soft to the hard breakdown regimes. - Highlights: • Gate and memory suitabilities of atomic layer deposited holmium titanium oxide. • Holmium titanium oxide exhibits resistive switching. • Layer thickness and holmium content influence the resistive switching. • Low and high resistance regimes follow a power-law model. • The power-law model can be extended to the hard breakdown regime.

  1. Noncontact ultrasonic nondestructive evaluation/inspection using laser generation and air coupled transducer

    International Nuclear Information System (INIS)

    Jhang, Kyung Young; Kim, Hong Joon; Cemiglia, Donatella; Djordjevic, Boro

    2001-01-01

    Ultrasonic MDE/I methods have been demonstrated as very effective tool in characterization of cracks and structural defects such as bond-line failures. Most of the ultrasonic testing is performed using conventional contact ultrasonic transducers that cannot be readily adapted to automation and field application. However, for large area inspection contact type is time consuming and as a result, it is important to develop a rapid and more efficient ultrasonic technique. In this paper, laser generation and air-coupled detection of ultrasound is proposed as a solution of non-contact method with no requirement of a coupling medium, and the bond quality of adhesively bonded and riveted aluminum lap splice joints is investigated as an application. A Q-switched Nd:YAG laser and a periodic transmission mask are used to generate a selected Lamb mode. The experimental show that multi-line laser source produces significant directed ultrasound and that the presence of defects can be detected reliably from the attenuation of signal amplitude. These results demonstrate that the proposed technique is well suitable and flexible for non-contact NDE/I applications.

  2. Nd:YAG Laser-Based Dual-Line Detection Rayleigh Scattering and Current Efforts on UV, Filtered Rayleigh Scattering

    Science.gov (United States)

    Otugen, M. Volkan; Popovic, Svetozar

    1996-01-01

    Ongoing research in Rayleigh scattering diagnostics for variable density low speed flow applications and for supersonic flow measurements are described. During the past several years, the focus has been on the development and use of a Nd:YAG-based Rayleigh scattering system with improved signal-to-noise characteristics and with applicability to complex, confined flows. This activity serves other research projects in the Aerodynamics Laboratory which require the non-contact, accurate, time-frozen measurement of gas density, pressure, and temperature (each separately), in a fairly wide dynamic range of each parameter. Recently, with the acquisition of a new seed-injected Nd:YAG laser, effort also has been directed to the development of a high-speed velocity probe based on a spectrally resolved Rayleigh scattering technique.

  3. Effect of silver nanoparticles on the dielectric properties of holmium doped silica glass

    International Nuclear Information System (INIS)

    Rejikumar, P.R.; Jyothy, P.V.; Mathew, Siby; Thomas, Vinoy; Unnikrishnan, N.V.

    2010-01-01

    The effect of silver nanoparticle co-doping on the dielectric properties of holmium doped silica glasses was studied. Silver nanoparticles of size between 20 and 22 nm were produced by the sol-gel technique. One of the samples showed an icosahedral morphology of the nanocrystal formed, along with spherical morphology. It was found that the tuning of the dielectric constant values could be accomplished by co-doping. The sample, with 1 wt% of Ho, had low dielectric constant values within the range 100 Hz-3 MHz due to the formation of quasi-molecular structures of holmium. This effect was evaded to some extent with silver co-doping as a result of the interdispersion of holmium complexes. Also it was found that the co-doping produced a higher dielectric loss which was calculated from the tan δ-log f graph. The Cole-Cole parameters and the Jonscher power law parameters were also calculated and are presented.

  4. Chitosan microspheres loaded with holmium-165 produced by spray dryer for liver cancer therapy: preliminary experiments

    International Nuclear Information System (INIS)

    Miyamoto, Douglas Massao; Pires, Geovanna; Lira, Raphael A. de; Melo, Vitor H.S.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de; Osso Junior, Joao Alberto

    2011-01-01

    Chitosan is a biopolymer of 2-deoxy-2-amino-D-glucose that is obtained by deacetylation of chitin. It's biocompatible, biodegradable, non toxic and has antitumor activity. Chitosan has many applications, such as their microparticles that can be used to treat prostate cancer, rheumatoid arthritis, and for liver tumor brachytherapy treatment. Our group is developing different biodegradable polymer-based microspheres loaded with holmium-165 for this purpose. The Chitosan microspheres were produced loaded with holmium (III) chloride, and not loaded with it, by Mini Spray Dryer procedure. The microspheres were evaluated by scanning electron microscopy, energy dispersive spectroscopy (EDS), confocal laser scanning microscopy, thermogravimetric analysis, particle size, and X-ray diffraction. The EDS analysis confirmed the holmium chloride presence into the prepared chitosan microparticles. (author)

  5. Chitosan microspheres loaded with holmium-165 produced by spray dryer for liver cancer therapy: preliminary experiments

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Douglas Massao; Pires, Geovanna; Lira, Raphael A. de; Melo, Vitor H.S.; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de, E-mail: douglas.miyamoto@usp.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Osso Junior, Joao Alberto [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Radiofarmacia

    2011-07-01

    Chitosan is a biopolymer of 2-deoxy-2-amino-D-glucose that is obtained by deacetylation of chitin. It's biocompatible, biodegradable, non toxic and has antitumor activity. Chitosan has many applications, such as their microparticles that can be used to treat prostate cancer, rheumatoid arthritis, and for liver tumor brachytherapy treatment. Our group is developing different biodegradable polymer-based microspheres loaded with holmium-165 for this purpose. The Chitosan microspheres were produced loaded with holmium (III) chloride, and not loaded with it, by Mini Spray Dryer procedure. The microspheres were evaluated by scanning electron microscopy, energy dispersive spectroscopy (EDS), confocal laser scanning microscopy, thermogravimetric analysis, particle size, and X-ray diffraction. The EDS analysis confirmed the holmium chloride presence into the prepared chitosan microparticles. (author)

  6. Radiopharmaceuticals of DTPA, DMSA and EDTA labeled with holmium-166

    International Nuclear Information System (INIS)

    Rahman, M.; Matsouka, H.; Takami, S.; Terunuma, K.

    2001-01-01

    DTPA, DMSA and EDTA were labelled with 166 Ho of low specific activity, 250-275mCi/mg of Ho, produced from holmium oxide by the 165 Ho(n, g) 166 Ho reaction at a neutron flux of about 10 14 n.cm -2 .s -1 . Three pH ranges were selected in the study, viz. 2-3, 3-3.5 and 5-6. The labelling reactions were studied as chloride and nitrate solutions in aqueous and saline media at 30 min and 20-24 h of reaction. DTPA was labelled over 99, DMSA at about 90 and EDTA at 100.0% with 166 Ho. The complexes were found stable at all times of investigation. A beta chromatogram scanner was used to study by TLC the labelling reactions of DTPA and DMSA with the nuclide and by PC those of EDTA. A biodistribution study in three rats injected intravenous with a saline solution of 166 HoCl 3 [DTPA] at pH5.1 showed an initial uptake in blood, kidney and lung after 30 minutes. After four hours the complex was found to have cleared from blood and lung, and localized 100% in kidney. It was stable in vivo in the kidney after 24 hours. The g spectrum analysis did not show the formation of any impurity except the four characteristic g energies of 166 Ho. (author)

  7. Holmium-166-chico intracavitary radiation therapy for cystic brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Rhee, C. H.; Lee, S. H.; Jang, J. S.; Kim, E. H.; Choi, C. W.; Hong, S. W.; Lim, S. M. [Korea Cancer Center, Seoul (Korea, Republic of)

    1997-07-01

    Holmium-166-chitosan complex (Ho-166-chico) is injected into the unresectable seven cystic brain tumors (2 cases of metastatic brain tumors from lung cancer, 1 case of recurrent trigeminal neurinoma, 3 cases of recurrent low grade cystic astrocytomas, and 1 case of craniopharyngioma). The Ommaya reservoir was installed stereotactically. The cyst volume and wall thickness were measured by MRI before Ho-166-chico injection. The thickness of the cyst wall is up to 4 mm. Ho-166-chico (555-740 MBq) injected into the cyst to result in 25 Gy of dose to a cyst wall at a depth of 4 mm. Dose to the cyst wall was estimated by Monte Carlo simulation using the EGS4 code. All Ho-166-chico injected was assumed to be uniformly distributed in the spherical cyst. After Ho-166-chico injection, the distribution of isotopes was monitored by gamma camera. Two injections were administrated in two cases, and one injection in all the others. The response was evaluated with MRI. Four of 7 cases were shrunk in size with thinning of the cyst wall, 2 of 7 cases showed growth arrest, and one case showed progression. Estimated surface dose of cyst wall was between 78 and 2566 Gy. No one showed systemic absorption of Ho-166-chico, and specific complication associated with isotope injection. Ho-166-chico intracavitary radiation therapy for cystic brain tumor may be safe, and reliable method and deserves further evaluation.

  8. Optical and electrical doping of silicon with holmium

    International Nuclear Information System (INIS)

    Suyver, J.F.; Kik, P.G.; Kimura, T.; Polman, A.; Franzo, G.; Coffa, S.

    1999-01-01

    2 MeV holmium ions were implanted into Czochralski grown Si at a fluence of 5.5x10 14 Ho/cm 2 . Some samples were co-implanted with oxygen to a concentration of (7±1)x10 19 cm -3 . After recrystallization, strong Ho segregation to the surface is observed, which is fully suppressed by co-doping with O. After recrystallization, photoluminescence peaks are observed at 1.197, 1.96 and 2.06 μm, characteristic for the 5 I 6 → 5 I 8 and 5 I 7 → 5 I 8 transitions of Ho 3+ . The Ho 3+ luminescence lifetime at 1.197 μm is 14 ms at 12 K. The luminescence intensity shows temperature quenching with an activation energy of 11 meV, both with and without O co-doping. The observed PL quenching cannot be explained by free carrier Auger quenching, but instead must be due to energy backtransfer or electron hole pair dissociation. Spreading resistance measurements indicate that Ho exhibits donor behavior, and that in the presence of O the free carrier concentration is enhanced by more than two orders of magnitude. In the O co-doped sample 20% of the Ho 3+ was electrically active at room temperature

  9. Synthesis, Characterization and Thermal Diffusivity of Holmium and Praseodymium Zirconates

    Directory of Open Access Journals (Sweden)

    Stopyra M.

    2016-06-01

    Full Text Available A2B2O7 oxides with pyrochlore or defected fluorite structure are among the most promising candidates for insulation layer material in thermal barrier coatings. The present paper presents the procedure of synthesis of holmium zirconate Ho2Zr2O7 and praseodymium zirconate Pr2Zr2O7 via Polymerized-Complex Method (PCM. Thermal analysis of precursor revealed that after calcination at relatively low temperature (700°C fine-crystalline, single-phase material is obtained. Thermal diffusivity was measured in temperature range 25-200°C, Ho2Zr2O7 exhibits lower thermal diffusivity than Pr2Zr2O7. Additionally, PrHoZr2O7 was synthesized. The powder in as-calcined condition is single-phase, but during the sintering decomposition of solid solution took place and Ho-rich phase precipitated. This material exhibited the best insulating properties among the tested ones.

  10. Investigations on the potential of a low power diode pumped Er:YAG laser system for oral surgery

    Science.gov (United States)

    Stock, Karl; Wurm, Holger; Hausladen, Florian; Wagner, Sophia; Hibst, Raimund

    2015-02-01

    Flash lamp pumped Er:YAG-lasers are used in clinical practice for dental applications successfully. As an alternative, several diode pumped Er:YAG laser systems (Pantec Engineering AG) become available, with mean laser power of 2W, 15W, and 30W. The aim of the presented study is to investigate the potential of the 2W Er:YAG laser system for oral surgery. At first an appropriate experimental set-up was realized with a beam delivery and both, a focusing unit for non-contact tissue cutting and a fiber tip for tissue cutting in contact mode. In order to produce reproducible cuts, the samples (porcine gingiva) were moved by a computer controlled translation stage. On the fresh samples cutting depth and quality were determined by light microscopy. Afterwards histological sections were prepared and microscopically analyzed regarding cutting depth and thermal damage zone. The experiments show that low laser power ≤ 2W is sufficient to perform efficient oral soft tissue cutting with cut depth up to 2mm (sample movement 2mm/s). The width of the thermal damage zone can be controlled by the irradiation parameters within a range of about 50μm to 110μm. In general, thermal injury is more pronounced using fiber tips in contact mode compared to the focused laser beam. In conclusion the results reveal that even the low power diode pumped Er:YAG laser is an appropriate tool for oral surgery.

  11. Ureteroscopic holmium laser cutting for inadvertently sutured drainage tube (report of five cases).

    Science.gov (United States)

    Gao, Xu; Lu, Xin; Ren, Shancheng; Xu, Chuanliang; Sun, Yinghao

    2008-07-01

    The aim of this paper is to report a simple solution for inadvertently sutured drainage tube after urological surgery and discuss the different managements according to different types of this embarrassing complication. From September 2001 to January 2007, five inadvertently sutured drainage tubes were treated with ureteroscopic holmium laser cutting for the suture. All drainage tubes were removed after the operation without other complications. Holmium laser cutting via ureteroscope is a simple solution for the embarrassing problem of inadvertently sutured drainage tube. It can save the patient from undergoing another open surgery.

  12. Footwear traction and lower extremity noncontact injury.

    Science.gov (United States)

    Wannop, John W; Luo, Geng; Stefanyshyn, Darren J

    2013-11-01

    Football is the most popular high school sport; however, it has the highest rate of injury. Speculation has been prevalent that foot fixation due to high footwear traction contributes to injury risk. Therefore, the purpose of the study was to determine whether a relationship exists between the athlete's specific footwear traction (measured with their own shoes on the field of play) and lower extremity noncontact injury in high school football. For 3 yr, 555 high school football athletes had their footwear traction measured on the actual field of play at the start of the season, and any injury the athletes suffered during a game was recorded. Lower extremity noncontact injury rates, grouped based on the athlete's specific footwear traction (both translational and rotational), were compared. For translational traction, injury rate reached a peak of 23.3 injuries/1000 game exposures within the midrange of translational traction, before decreasing to 5.0 injuries/1000 game exposures in the high range of traction. For rotational traction, there was a steady increase in injury rate as footwear traction increased, starting at 4.2 injuries/1000 game exposures at low traction and reaching 19.2 injuries/1000 game exposures at high traction. A relationship exists between footwear traction and noncontact lower extremity injury, with increases in rotational traction leading to a greater injury rate and increases in translational traction leading to a decrease in injury. It is recommended that athletes consider selecting footwear with the lowest rotational traction values for which no detriment in performance results.

  13. Laser lithotripsy with the Ho:YAG laser: fragmentation process revealed by time-resolved imaging

    Science.gov (United States)

    Schmidlin, Franz R.; Beghuin, Didier; Delacretaz, Guy P.; Venzi, Giordano; Jichlinski, Patrice; Rink, Klaus; Leisinger, Hans-Juerg; Graber, Peter

    1998-07-01

    Improvements of endoscopic techniques have renewed the interest of urologists in laser lithotripsy in recent years. Laser energy can be easily transmitted through flexible fibers thereby enabling different surgical procedures such as cutting, coagulating and lithotripsy. The Ho:YAG laser offers multiple medical applications in Urology, among them stone fragmentation. However, the present knowledge of its fragmentation mechanism is incomplete. The objective was therefore to analyze the fragmentation process and to discuss the clinical implications related to the underlying fragmentation mechanism. The stone fragmentation process during Ho:YAG laser lithotripsy was observed by time resolved flash video imaging. Possible acoustic transient occurrence was simultaneously monitored with a PVDF-needle hydrophone. Fragmentation was performed on artificial and cystine kidney stones in water. We observed that though the fragmentation process is accompanied with the formation of a cavitation bubble, cavitation has only a minimal effect on stone fragmentation. Fragment ejection is mainly due to direct laser stone heating leading to vaporization of organic stone constituents and interstitial water. The minimal effect of the cavitation bubble is confirmed by acoustic transients measurements, which reveal weak pressure transients. Stone fragmentation with the Holmium laser is the result of vaporization of interstitial (stone) water and organic stone constituents. It is not due to the acoustic effects of a cavitation bubble or plasma formation. The fragmentation process is strongly related with heat production thereby harboring the risk of undesired thermal damage. Therefore, a solid comprehension of the fragmentation process is needed when using the different clinically available laser types of lithotripsy.

  14. Successful Treatment of Stent Knot in the Proximal Ureter Using Ureteroscopy and Holmium Laser

    Directory of Open Access Journals (Sweden)

    Masters M. Richards

    2011-01-01

    Full Text Available Knotted ureteral stent is rare yet tedious complication that might represent a treatment challenge to the endourologist. Only twelve cases of knotted stent have been reported. Different management options have been reported, including simple traction, ureteroscopy, percutaneous removal, and open surgery. In this paper, we present the successful untying of the knot using ureteroscopy with holmium laser.

  15. Comparison of ESWL and ureteroscopic holmium laser lithotripsy in management of ureteral stones.

    Science.gov (United States)

    Cui, Yon; Cao, Wenzhou; Shen, Hua; Xie, Jianjun; Adams, Tamara S; Zhang, Yuanyuan; Shao, Qiang

    2014-01-01

    There are many options for urologists to treat ureteral stones that range from 8 mm to 15 mm, including ESWL and ureteroscopic holmium laser lithotripsy. While both ESWL and ureteroscopy are effective and minimally invasive procedures, there is still controversy over which one is more suitable for ureteral stones. To perform a retrospective study to compare the efficiency, safety and complications using ESWL vs. ureteroscopic holmium laser lithotripsy in management of ureteral stones. Between October 2010 and October 2012, 160 patients who underwent ESWL or ureteroscopic holmium laser lithotripsy at Suzhou municipal hospital for a single radiopaque ureteral stone (the size 8-15 mm) were evaluated. All patients were followed up with ultrasonography for six months. Stone clearance rate, costs and complications were compared. Similarity in stone clearance rate and treatment time between the two procedures; overall procedural time, analgesia requirement and total cost were significantly different. Renal colic and gross hematuria were more frequent with ESWL while voiding symptoms were more frequent with ureteroscopy. Both procedures used for ureteral stones ranging from 8 to 15 mm were safe and minimally invasive. ESWL remains first line therapy for proximal ureteral stones while ureteroscopic holmium laser lithotripsy costs more. To determining which one is preferable depends on not only stone characteristics but also patient acceptance and cost-effectiveness ratio.

  16. Comparison of ESWL and ureteroscopic holmium laser lithotripsy in management of ureteral stones.

    Directory of Open Access Journals (Sweden)

    Yon Cui

    Full Text Available BACKGROUND: There are many options for urologists to treat ureteral stones that range from 8 mm to 15 mm, including ESWL and ureteroscopic holmium laser lithotripsy. While both ESWL and ureteroscopy are effective and minimally invasive procedures, there is still controversy over which one is more suitable for ureteral stones. OBJECTIVE: To perform a retrospective study to compare the efficiency, safety and complications using ESWL vs. ureteroscopic holmium laser lithotripsy in management of ureteral stones. METHODS: Between October 2010 and October 2012, 160 patients who underwent ESWL or ureteroscopic holmium laser lithotripsy at Suzhou municipal hospital for a single radiopaque ureteral stone (the size 8-15 mm were evaluated. All patients were followed up with ultrasonography for six months. Stone clearance rate, costs and complications were compared. RESULTS: Similarity in stone clearance rate and treatment time between the two procedures; overall procedural time, analgesia requirement and total cost were significantly different. Renal colic and gross hematuria were more frequent with ESWL while voiding symptoms were more frequent with ureteroscopy. Both procedures used for ureteral stones ranging from 8 to 15 mm were safe and minimally invasive. CONCLUSION: ESWL remains first line therapy for proximal ureteral stones while ureteroscopic holmium laser lithotripsy costs more. To determining which one is preferable depends on not only stone characteristics but also patient acceptance and cost-effectiveness ratio.

  17. Wound repair in rat urinary bladder following electrocautery or holmium laser incision

    Science.gov (United States)

    Venzi, Giordano; Schmidlin, Franz R.; Gabbiani, Giulio; Delacretaz, Guy P.; Pittet, Brigitte; Leisinger, Hans-Juerg; Iselin, Christoph E.

    1999-06-01

    Woundhealing is a complex phenomenon which varies according the type of tissue but is also depending from the type of tissue injury. Electrocautery mainly induces coagulation necrosis while thermal damages induced by the Holmium laser primarily lead to tissue vaporization which may induce less tissue injury. The aim of this study was to evaluate the healing process of the Holmium laser induced lesions compared to electrocautery induced lesions in urothelial tissue by assessing the inflammatory response and myofibroblast behavior in sequential healing phases. A surgical wound was created in the urinary rat bladder of 32 rats either by electrocautery or by laser (N=16). The inflammatory response, the total lesion depth and the myofibroblast activity during woundhealing was then analyzed on a qualitative basis on days 0/2/4/8. The overall inflammatory response was comparable in both groups up to days two and four. However, at day eight less cellular inflammatory reaction and less myofibroblast activity was found in the specimen of lesions created by the Holmium laser. These results suggest that wound repair may be a less invasive process after Holmium laser than electrocautery.

  18. Analysis of Non-contact Acousto Thermal Signature Data (Postprint)

    Science.gov (United States)

    2016-02-01

    AFRL-RX-WP-JA-2016-0321 ANALYSIS OF NON-CONTACT ACOUSTO-THERMAL SIGNATURE DATA (POSTPRINT) Amanda K. Criner AFRL/RX...October 2014 – 16 September 2015 4. TITLE AND SUBTITLE ANALYSIS OF NON-CONTACT ACOUSTO-THERMAL SIGNATURE DATA (POSTPRINT) 5a. CONTRACT NUMBER...words) The non-contact acousto-thermal signature (NCATS) is a nondestructive evaluation technique with potential to detect fatigue in materials such as

  19. Clinical tonometric measurements comparing three non-contact tonometers.

    Science.gov (United States)

    Walby, M A; Augsburger, A; Polasky, M

    1975-06-01

    Three American Optical Non-contact Tonometers were used to compare readings against each other. The attempt was to determine if all three tonometers were measuring the same IOP over a wide range of pressures. The assumption in practice is that all Non-contact Tonometers are manufactured within tolerance that should allow the examiner to find that same IOP on a patient regardless of the Non-contact Tonometer used. A preliminary study found no significant difference between the instruments.

  20. 3d noncontact humidity sensing technologies and methods of use thereof

    KAUST Repository

    Tai, Yanlong; Lubineau, Gilles

    2017-01-01

    Noncontact sensing components are provided herein, in an aspect, they can be for an electronic device. The noncontact sensing components can contain a semiconductor layer having a r-GO portion and a CNT portion. The noncontact sensing components can

  1. Study of structural and optical properties of YAG and Nd:YAG single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Kostić, S. [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Lazarević, Z.Ž., E-mail: lzorica@yahoo.com [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Radojević, V. [Faculty of Technology and Metallurgy, University of Belgrade, Belgrade (Serbia); Milutinović, A.; Romčević, M.; Romčević, N.Ž. [Institute of Physics, University of Belgrade, P.O. Box 68, Pregrevica 118, Zemun, Belgrade (Serbia); Valčić, A. [Faculty of Technology and Metallurgy, University of Belgrade, Belgrade (Serbia)

    2015-03-15

    Highlights: • Transparent YAG and pale pink Nd:YAG single crystals were produced by the Czochralski technique. • Growth mechanisms and shape of the liquid/solid interface and incorporation of Nd{sup 3+} were studied. • The structure of the crystals was investigated by X-ray diffraction, Raman and IR spectroscopy. • The 15 Raman and 17 IR modes were observed. • The obtained YAG and Nd:YAG single crystals were without core and of good optical quality. - Abstract: Yttrium aluminum garnet (YAG, Y{sub 3}Al{sub 5}O{sub 12}) and yttrium aluminum garnet doped with neodymium (Nd:YAG) single crystals were grown by the Czochralski technique. The critical diameter and the critical rate of rotation were calculated. Suitable polishing and etching solutions were determined. As a result of our experiments, the transparent YAG and pale pink Nd:YAG single crystals were produced. The obtained crystals were studied by X-ray diffraction, Raman and IR spectroscopy. The crystal structure was confirmed by XRD. The 15 Raman and 17 IR modes were observed. The Raman and IR spectroscopy results are in accordance with X-ray diffraction analysis. The obtained YAG and Nd:YAG single crystals were without core and of good optical quality. The absence of a core was confirmed by viewing polished crystal slices. Also, it is important to emphasize that the obtained Nd:YAG single crystal has a concentration of 0.8 wt.% Nd{sup 3+} that is characteristic for laser materials.

  2. Noncontact simultaneous dual wavelength photoplethysmography: A further step toward noncontact pulse oximetry

    International Nuclear Information System (INIS)

    Humphreys, Kenneth; Ward, Tomas; Markham, Charles

    2007-01-01

    We present a camera-based device capable of capturing two photoplethysmographic (PPG) signals at two different wavelengths simultaneously, in a remote noncontact manner. The system comprises a complementary metal-oxide semiconductor camera and dual wavelength array of light emitting diodes (760 and 880 nm). By alternately illuminating a region of tissue with each wavelength of light, and detecting the backscattered photons with the camera at a rate of 16 frames/wavelength s, two multiplexed PPG wave forms are simultaneously captured. This process is the basis of pulse oximetry, and we describe how, with the inclusion of a calibration procedure, this system could be used as a noncontact pulse oximeter to measure arterial oxygen saturation (S p O 2 ) remotely. Results from an experiment on ten subjects, exhibiting normal S p O 2 readings, that demonstrate the instrument's ability to capture signals from a range of subjects under realistic lighting and environmental conditions are presented. We compare the signals captured by the noncontact system to a conventional PPG signal captured concurrently from a finger, and show by means of a J. Bland and D. Altman [Lancet 327, 307 (1986); Statistician 32, 307 (1983)] test, the noncontact device to be comparable to a contact device as a monitor of heart rate. We highlight some considerations that should be made when using camera-based ''integrative'' sampling methods and demonstrate through simulation, the suitability of the captured PPG signals for application of existing pulse oximetry calibration procedures

  3. Noncontact simultaneous dual wavelength photoplethysmography: A further step toward noncontact pulse oximetry

    Science.gov (United States)

    Humphreys, Kenneth; Ward, Tomas; Markham, Charles

    2007-04-01

    We present a camera-based device capable of capturing two photoplethysmographic (PPG) signals at two different wavelengths simultaneously, in a remote noncontact manner. The system comprises a complementary metal-oxide semiconductor camera and dual wavelength array of light emitting diodes (760 and 880nm). By alternately illuminating a region of tissue with each wavelength of light, and detecting the backscattered photons with the camera at a rate of 16frames/wavelengths, two multiplexed PPG wave forms are simultaneously captured. This process is the basis of pulse oximetry, and we describe how, with the inclusion of a calibration procedure, this system could be used as a noncontact pulse oximeter to measure arterial oxygen saturation (SpO2) remotely. Results from an experiment on ten subjects, exhibiting normal SpO2 readings, that demonstrate the instrument's ability to capture signals from a range of subjects under realistic lighting and environmental conditions are presented. We compare the signals captured by the noncontact system to a conventional PPG signal captured concurrently from a finger, and show by means of a J. Bland and D. Altman [Lancet 327, 307 (1986); Statistician 32, 307 (1983)] test, the noncontact device to be comparable to a contact device as a monitor of heart rate. We highlight some considerations that should be made when using camera-based "integrative" sampling methods and demonstrate through simulation, the suitability of the captured PPG signals for application of existing pulse oximetry calibration procedures.

  4. Densification behavior, doping profile and planar waveguide laser performance of the tape casting YAG/Nd:YAG/YAG ceramics

    Science.gov (United States)

    Ge, Lin; Li, Jiang; Qu, Haiyun; Wang, Juntao; Liu, Jiao; Dai, Jiawei; Zhou, Zhiwei; Liu, Binglong; Kou, Huamin; Shi, Yun; Wang, Zheng; Pan, Yubai; Gao, Qingsong; Guo, Jingkun

    2016-10-01

    The sintering behavior and doping concentration profile of the planar waveguide YAG/Nd:YAG/YAG ceramics by the tape casting and solid-state reaction method were investigated on the basis of densification trajectory, microstructure evolution, and Nd3+ ions diffusion. The porosity of the green body by tape casting and cold isostatic pressing is about 38.6%. And the green bodies were consolidated from 1100 °C to 1800 °C for 0.5-20 h to study the densification and the doping diffusion behaviors. At the temperature higher than 1500 °C, pure YAG phase is formed, followed by the densification and grain growth process. With the increase of temperature, two sintering stages occur, corresponding to remarkable densification and significant grain growth, respectively. The mechanism controlling densification at 1550 °C is grain boundary diffusion. The diffusion of Nd3+ ions is more sensitive to temperature than the sintering time, and the minimum temperature required for the obvious diffusion of Nd3+ ions is higher than 1700 °C. Finally, planar waveguide YAG/1.5 at.%Nd:YAG/YAG transparent ceramics with in-line transmittance of 84.8% at 1064 nm were obtained by vacuum-sintering at 1780 °C for 30 h. The fluorescence lifetime of 4F3/2 state of Nd3+ in the specimen is about 259 μs. The prepared ceramic waveguide was tested in a laser amplifier and the laser pulse was amplificated from 87 mJ to 238 mJ, with the pump energy of 680 mJ.

  5. Preparation and characterization of highly transparent Nd:YAG/YAG composite ceramics

    Science.gov (United States)

    Ma, Benyuan; Zhang, Wei; Shen, Bizhou; Wang, Yuezhong; Song, Haizhi; Li, Feng; Xie, Xiumin; Zhang, Zhibin; Yang, Yongqiang; Guan, Zhouguo

    2018-05-01

    Using the co-precipitated Nd:YAG and YAG powders as raw materials, the Nd:YAG/YAG composite ceramics (Ф 50 mm × 5 mm) were prepared by vacuum sintering (1790 °C 50 h), followed by hot isostatic pressing (HIP) post treatment (1700 °C 2 h, 200 MPa Ar atmosphere) and air annealing (1250 °C 100 h). The optical properties of Nd:YAG/YAG samples were improved markedly by HIP post-treatment, mainly due to the elimination of residual pores in the samples. The composite sample showed a perfect bonding interface from Nd:YAG to YAG regions without obvious grain size difference, pores or other defects. This structure should be responsible for the thermal conductivity larger than that of non-composite sample. The composite sample revealed good optical properties with transmittance up to 83.9% at 1064 nm and 80.8% at 400 nm, and a maximum laser output power of 1.38 KW with the slope efficiency of 36.7% was obtained.

  6. Fine- and hyperfine structure investigations of the even-parity configuration system of the atomic holmium

    Science.gov (United States)

    Stefanska, D.; Ruczkowski, J.; Elantkowska, M.; Furmann, B.

    2018-04-01

    In this work new experimental results concerning the hyperfine structure (hfs) for the even-parity level system of the holmium atom (Ho I) were obtained; additionally, hfs data obtained recently as a by-product in investigations of the odd-parity level system were summarized. In the present work the values of the magnetic dipole and the electric quadrupole hfs constants A and B were determined for 24 even-parity levels, for 14 of them for the first time. On the basis of these results, as well as on available literature data, a parametric study of the fine structure and the hyperfine structure for the even-parity configurations of atomic holmium was performed. A multi-configuration fit of 7 configurations was carried out, taking into account second-order of the perturbation theory. For unknown electronic levels predicted values of the level energies and hfs constants are given, which can facilitate further experimental investigations.

  7. Calcium phosphate holmium-166 ceramic to addition in bone cement: synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Donanzam, Blanda A.; Campos, Tarcisio P.R., E-mail: campos@nuclear.ufmg.b [Universidade do Federal de Minas Gerais (DEN/UFMG), Belo Horizonte, MG (Brazil). Escola de Engenharia. Dept. de Engenharia Nuclear; Dalmazio, Ilza; Valente, Eduardo S., E-mail: id@cdtn.b, E-mail: valente@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    Spine metastases are a common and painful complication of cancer. The treatment often consists of bone cement injection (vertebroplasty or kyphoplasty) within vertebral body for vertebrae stabilization, followed by external beam radiation therapy. Recently, researchers introduced the concept of radioactive bone cement for spine tumors therapy. Then, investigations about bioactive and radioactive materials became interesting. In this study, we present the synthesis of calcium phosphate incorporated holmium (CaP-Ho) via sol-gel technique, and its characterization by XRD, FT-IR, NA and SEM. Results showed a multiphasic bioceramic composed mainly of hydroxyapatite, {beta}-tricalcium phosphate, holmium phosphate and traces of calcium pyrophosphate. Furthermore, the nuclide Ho-166 was the major radioisotope produced. Despite that, the radioactive bioceramic CaP-{sup 166}Ho must be investigated in clinical trials to assure its efficacy and safety on spine tumors treatment (author)

  8. Calcium phosphate holmium-166 ceramic to addition in bone cement: synthesis and characterization

    International Nuclear Information System (INIS)

    Donanzam, Blanda A.; Campos, Tarcisio P.R.

    2011-01-01

    Spine metastases are a common and painful complication of cancer. The treatment often consists of bone cement injection (vertebroplasty or kyphoplasty) within vertebral body for vertebrae stabilization, followed by external beam radiation therapy. Recently, researchers introduced the concept of radioactive bone cement for spine tumors therapy. Then, investigations about bioactive and radioactive materials became interesting. In this study, we present the synthesis of calcium phosphate incorporated holmium (CaP-Ho) via sol-gel technique, and its characterization by XRD, FT-IR, NA and SEM. Results showed a multiphasic bioceramic composed mainly of hydroxyapatite, β-tricalcium phosphate, holmium phosphate and traces of calcium pyrophosphate. Furthermore, the nuclide Ho-166 was the major radioisotope produced. Despite that, the radioactive bioceramic CaP- 166 Ho must be investigated in clinical trials to assure its efficacy and safety on spine tumors treatment (author)

  9. Safety of holmium laser prostatectomy in patients with cardiac pacemaker implant

    Directory of Open Access Journals (Sweden)

    Narmada P Gupta

    2006-01-01

    Full Text Available Objectives: The use of the standard monopolar electrocautery is associated with significant risks of implant malfunction in patients on a cardiac pacemaker. It is also associated with a risk of adverse cardiac events due to blood loss and fluid absorption. The properties of the holmium laser prevent the occurrence of these adverse events. We report the successful use of this technology in resecting the gland in patients on a permanent cardiac pacemaker implant. MATERIALS AND Methods: Six patients with permanent cardiac pacemaker implant were treated with holmium laser resection of prostate over a period of two years. Treated patients had bothersome prostatic symptoms and failed to respond to medical therapy. All patients were operated under spinal anesthesia using a high power VersaPulse ® PowerSuiteTM Holmium laser source. Normal saline was used as irrigant. Intravesical tissue morcellator was also used to remove the larger fragments in two of the patients. Results : Median patient age was 60 years (range 56-73 and median prostate volume was 40cc (range 20-48cc. None of the patient required blood transfusion or had significant hyponatremia or Transurethral resection syndrome. No patients had any pacemaker malfunction or hemodynamic instability during the procedure or in immediate postoperative period. Improvement in maximum urine flow rate was observed from an average of 7 ml/sec in preoperative period to 22 ml/sec postoperatively at 3 month followup. Conclusions: Holmium laser prostatectomy offers the ideal modality of surgery in patients on a cardiac pacemaker. It helps to avoid additional preparation and minimizes the risk of device malfunction and adverse post operative events.

  10. A holmium(III)-based single-molecule magnet with pentagonal-bipyramidal geometry

    Energy Technology Data Exchange (ETDEWEB)

    Kajiwara, Takashi [Department of Chemistry, Faculty of Science, Nara Women' s University (Japan)

    2017-09-11

    The right environment: The remarkable properties of a recently reported holmium(III)-based single-ion magnet have been ascribed to the hyperfine interactions with the half-integer nuclear spin in combination with the pentagonal-bipyramidal coordination environment. These results provide insight into the complicated magnetic properties of nanosized magnetic materials. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Material science as basis for nuclear medicine: Holmium irradiation for radioisotopes production

    Science.gov (United States)

    Usman, Ahmed Rufai; Khandaker, Mayeen Uddin; Haba, Hiromitsu; Otuka, Naohiko

    2018-05-01

    Material Science, being an interdisciplinary field, plays important roles in nuclear science. These applications are seen in weaponry, armoured vehicles, accelerator structure and development, semiconductor detectors, nuclear medicine and many more. Present study presents the applications of some metals in nuclear medicine (radioisotope production). The charged-particle-induced nuclear reactions by using cyclotrons or accelerators have become a very vital feature of the modern nuclear medicine. Realising the importance of excitation functions for the efficient production of medical radionuclides, some very high purity holmium metals are generally prepared or purchased for bombardment in nuclear accelerators. In the present work, various methods to obtain pure holmium for radioisotope production have been discussed while also presenting details of our present studies. From the experimental work of the present studies, some very high purity holmium foils have been used in the work for a comprehensive study of residual radionuclides production cross-sections. The study was performed using a stacked-foil activation technique combined with γ-ray spectrometry. The stack was bombarded with 50.4 MeV alpha particle beam from AVF cyclotron of RI Beam Factory, Nishina Centre for Accelerator-Based Science, RIKEN, Japan. The work produced thulium radionuclides useful in nuclear medicine.

  12. Noncontact fatigue crack evaluation using thermoelastic

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Min; An, Yun Kyu; Sohn, Hoon [KAIST, Daejeon (Korea, Republic of)

    2012-12-15

    This paper proposes a noncontact thermography technique for fatigue crack evaluation under a cyclic tensile loading. The proposed technique identifies and localizes an invisible fatigue crack without scanning, thus making it possible to instantaneously evaluate an incipient fatigue crack. Based on a thermoelastic theory, a new fatigue crack evaluation algorithm is proposed for the fatigue crack tip localization. The performance of the proposed algorithm is experimentally validated. To achieve this, the cyclic tensile loading is applied to a dog bone shape aluminum specimen using a universal testing machine, and the corresponding thermal responses induced by thermoelastic effects are captured by an infrared camera. The test results confirm that the fatigue crack is well identified and localized by comparing with its microscopic images.

  13. EPro Non-contact erosion profiling

    DEFF Research Database (Denmark)

    Meinert, Palle

    Pro is a profiling program build to measure the same surface or work piece multiple times and track changes due to erosion. It was developed during 2001 - 2002 at Aalborg University and was part of a Master of Science project dealing with stability of rubble mound breakwaters. The goal was to aut......Pro is a profiling program build to measure the same surface or work piece multiple times and track changes due to erosion. It was developed during 2001 - 2002 at Aalborg University and was part of a Master of Science project dealing with stability of rubble mound breakwaters. The goal...... was to automate the measuring of profiles in order to save manpower and to increase the number of possible measure points. Additional requirement was that measurements should be done in a non-contact way and that the measuring should not be hindered by the presence of water....

  14. Non-contact radiation thickness gauge

    International Nuclear Information System (INIS)

    Tsujii, T.; Okino, T.

    1983-01-01

    A noncontact thickness gauge system for measuring the thickness of a material comprising a source of radiation, a detector for detecting the amount of radiation transmitted through the material which is a function of the absorptance and thickness of the material, a memory for storing the output signals of the detector and curve-defining parameters for a plurality of quadratic calibration curves which correspond to respective thickness ranges, and a processor for processing the signals and curve defining parameters to determine the thickness of the material. Measurements are made after precalibration to obtain calibration curves and these are stored in the memory, providing signals representative of a nominal thickness and an alloy compensation coefficient for the material. The calibration curve corresponding to a particular thickness range is selected and the curve compensated for drift; the material is inserted into the radiation path and the detector output signal processed with the compensated calibration curve to determine the thickness of the material. (author)

  15. Visual internal urethrotomy for management of urethral strictures in boys: a comparison of short-term outcome of holmium laser versus cold knife.

    Science.gov (United States)

    Aboulela, Waseem; ElSheemy, Mohammed S; Shoukry, Mahmoud; Shouman, Ahmed M; Shoukry, Ahmed I; Ghoneima, Waleed; El Ghoneimy, Mohamed; Morsi, Hany A; Mohsen, Mostafa Abdel; Badawy, Hesham

    2018-04-01

    To compare efficacy and safety of visual internal urethrotomy (VIU) using holmium laser (Ho:YAG) (group A) versus cold knife (group B) in children with urethral strictures. It may be the first comparative study on this issue in children. This study compared Ho:YAG group, which was evaluated prospectively from January 2014 till January 2016, versus cold knife group, which was a historical control performed from March 2008 till February 2010. Children ≤ 13 years old with urethral strictures ≤ 1.5 cm were included successively. Recurrent cases, congenital obstructions and cases with complete arrest of dye in voiding cystourethrography were excluded. Scar tissue was incised at twelve o'clock. Outcome was compared using Student's t, Mann-Whitney, Chi-square or Fisher exact tests as appropriate. Each group included 21 patients. Mean age was 6.27 ± 3.23 (2-13) years old. Mean stricture length was 1.02 versus 1 cm in group A versus B, respectively (p = 0.862). Ten cases of penile/bulbous strictures and another 11 cases of membranous strictures were found in each group. There was no significant difference between both groups in preoperative data. Success rate for initial VIU was 66.7% in group A versus 38% in group B (p = 0.064). This was associated with significantly higher Q max in group A (mean 16.52 vs 12.09 ml/s; p = 0.03). Success rate after two trials of VIU was 76.2% for group A and 47.61% for group B (p = 0.057). No complications were reported in both groups. Laser VIU has a higher success rate than cold knife VIU for urethral strictures ≤ 1.5 cm in children with significantly higher Q max . Both are easy to perform, low invasive and safe.

  16. Actively Q-switched laser with novel Nd:YAG/YAG polygonal active-mirror

    Science.gov (United States)

    Lang, Ye; Chen, Yanzhong; Ge, Wenqi; He, Jianguo; Zhang, Hongbo; Liao, Lifen; Xin, Jianguo; Zhang, Jian; Fan, Zhongwei

    2018-03-01

    In this work, we demonstrate an efficient actively Q-switched laser based on a novel crystal Nd:YAG/YAG polygonal active mirror. A passively cooled crystal Nd:YAG/YAG polygonal active mirror with an end pump scheme was used as the gain medium. For the overlap between the TEM00 laser mode and large gain profile, a cavity was carefully designed with a large fundamental mode volume. With a maximum absorbed power of 3.1 W, a 685 mW average output power with a pulse repetition of 5 kHz was attained, and the corresponding optical-optical and slope efficiency were 22.1% and 27.7%, respectively. The pulse width was 133.9 ns. The beam quality (M 2) was 1.561 in the horizontal direction and 1.261 in the vertical direction.

  17. An All-Fiber-Optic Combined System of Noncontact Photoacoustic Tomography and Optical Coherence Tomography.

    Science.gov (United States)

    Eom, Jonghyun; Shin, Jun Geun; Park, Soongho; Rim, Sunghwan; Lee, Byeong Ha

    2016-05-20

    We propose an all-fiber-based dual-modal imaging system that combines noncontact photoacoustic tomography (PAT) and optical coherence tomography (OCT). The PAT remotely measures photoacoustic (PA) signals with a 1550-nm laser on the surface of a sample by utilizing a fiber interferometer as an ultrasound detector. The fiber-based OCT, employing a swept-source laser centered at 1310 nm, shares the sample arm of the PAT system. The fiber-optic probe for the combined system was homemade with a lensed single-mode fiber (SMF) and a large-core multimode fiber (MMF). The compact and robust common probe is capable of obtaining both the PA and the OCT signals at the same position without any physical contact. Additionally, the MMF of the probe delivers the short pulses of a Nd:YAG laser to efficiently excite the PA signals. We experimentally demonstrate the feasibility of the proposed dual-modal system with a phantom made of a fishing line and a black polyethylene terephthalate fiber in a tissue mimicking solution. The all-fiber-optic system, capable of providing complementary information about absorption and scattering, has a promising potential in minimally invasive and endoscopic imaging.

  18. An All-Fiber-Optic Combined System of Noncontact Photoacoustic Tomography and Optical Coherence Tomography

    Science.gov (United States)

    Eom, Jonghyun; Shin, Jun Geun; Park, Soongho; Rim, Sunghwan; Lee, Byeong Ha

    2016-01-01

    We propose an all-fiber-based dual-modal imaging system that combines noncontact photoacoustic tomography (PAT) and optical coherence tomography (OCT). The PAT remotely measures photoacoustic (PA) signals with a 1550-nm laser on the surface of a sample by utilizing a fiber interferometer as an ultrasound detector. The fiber-based OCT, employing a swept-source laser centered at 1310 nm, shares the sample arm of the PAT system. The fiber-optic probe for the combined system was homemade with a lensed single-mode fiber (SMF) and a large-core multimode fiber (MMF). The compact and robust common probe is capable of obtaining both the PA and the OCT signals at the same position without any physical contact. Additionally, the MMF of the probe delivers the short pulses of a Nd:YAG laser to efficiently excite the PA signals. We experimentally demonstrate the feasibility of the proposed dual-modal system with a phantom made of a fishing line and a black polyethylene terephthalate fiber in a tissue mimicking solution. The all-fiber-optic system, capable of providing complementary information about absorption and scattering, has a promising potential in minimally invasive and endoscopic imaging. PMID:27213392

  19. An All-Fiber-Optic Combined System of Noncontact Photoacoustic Tomography and Optical Coherence Tomography

    Directory of Open Access Journals (Sweden)

    Jonghyun Eom

    2016-05-01

    Full Text Available We propose an all-fiber-based dual-modal imaging system that combines noncontact photoacoustic tomography (PAT and optical coherence tomography (OCT. The PAT remotely measures photoacoustic (PA signals with a 1550-nm laser on the surface of a sample by utilizing a fiber interferometer as an ultrasound detector. The fiber-based OCT, employing a swept-source laser centered at 1310 nm, shares the sample arm of the PAT system. The fiber-optic probe for the combined system was homemade with a lensed single-mode fiber (SMF and a large-core multimode fiber (MMF. The compact and robust common probe is capable of obtaining both the PA and the OCT signals at the same position without any physical contact. Additionally, the MMF of the probe delivers the short pulses of a Nd:YAG laser to efficiently excite the PA signals. We experimentally demonstrate the feasibility of the proposed dual-modal system with a phantom made of a fishing line and a black polyethylene terephthalate fiber in a tissue mimicking solution. The all-fiber-optic system, capable of providing complementary information about absorption and scattering, has a promising potential in minimally invasive and endoscopic imaging.

  20. The non-contact tonometer. Its value and limitations.

    Science.gov (United States)

    Shields, M B

    1980-01-01

    A review of the literature and a comparative study against Goldmann applanation tonometers suggest that the non-contact tonometer is reliable for measuring intraocular pressures within the normal range. In addition, the non-contact tonometer eliminates the need for corneal contact and topical anesthesia, thereby avoiding the potential problems of corneal abrasion, spread of infection, and drug reactions. The instrument can be used reliably by paramedical personnel and has particular value in mass screening and possibly in studies of topical antiglaucoma drugs. The non-contact tonometer is less reliable in patients with elevated intraocular pressure, since comparative studies against the Goldmann applanation tonometers have shown poorer correlations in the higher pressure ranges. The instrument is also limited by an abnormal cornea or poor fixation, which may interfere with accurate pressure measurements. Furthermore, the non-contact tonometer is less portable than many tonometers and more expensive than most.

  1. Nd:YAG laser for holography

    International Nuclear Information System (INIS)

    Bykovsky, Yu.A.; Evtihiev, N.N.; Larkin, A.I.

    1982-01-01

    Different possibilities to use photonics, holography and optical processing for nuclear physics has been investigated in our works. The paper presents the results of the study of time and spatial coherence of Nd:YAG laser and application in holography. (orig./HSI)

  2. Noncontact sheet resistance measurement technique for wafer inspection

    Science.gov (United States)

    Kempa, Krzysztof; Rommel, J. Martin; Litovsky, Roman; Becla, Peter; Lojek, Bohumil; Bryson, Frank; Blake, Julian

    1995-12-01

    A new technique, MICROTHERM, has been developed for noncontact sheet resistance measurements of semiconductor wafers. It is based on the application of microwave energy to the wafer, and simultaneous detection of the infrared radiation resulting from ohmic heating. The pattern of the emitted radiation corresponds to the sheet resistance distribution across the wafer. This method is nondestructive, noncontact, and allows for measurements of very small areas (several square microns) of the wafer.

  3. Non-contact transportation using near-field acoustic levitation

    Science.gov (United States)

    Ueha; Hashimoto; Koike

    2000-03-01

    Near-field acoustic levitation, where planar objects 10 kg in weight can levitate stably near the vibrating plate, is successfully applied both to non-contact transportation of objects and to a non-contact ultrasonic motor. Transporting apparatuses and an ultrasonic motor have been fabricated and their characteristics measured. The theory of near-field acoustic levitation both for a piston-like sound source and a flexural vibration source is also briefly described.

  4. Active noncontact tonometer for glaucoma detection

    Science.gov (United States)

    Han, Yanmei; Bryanston-Cross, Peter J.; Lee, Wing K. A.; Hero, Mark

    2002-09-01

    Glaucoma is an increasingly common cause of visual impairment, and in some cases causes blindness. The approach to develop a low cost and non-contact tonometer for the detection of glaucoma, to replace the Goldmann tonometer used worldwide, is presented in this paper. The new tonometer exploits the vibration property of the cornea - the resonance frequency of the cornea rises with increasing intra-ocular pressure (IOP). An audio frequency signal is used to vibrate the cornea of the eye, the vibration of the cornea is measured using a fibre optic lever probe, and then the IOP can be calculated from the detected resonance frequency of the cornea. The initial PC-version experiment system of the new tonometer has been demonstrated and preliminary testing has been performed, showing a suitable sensitivity in detecting the resonance frequency against the IOP using both the simulated-eye model and the pig's eye. The initial system has been improved to be suitable for greater than 15mm detecting distance, and the measurement of vibrations of human cornea in-vivo has been carried out. Work is now focusing on increasing the sensitivity of the fibre probe, and reducing the measuring time to less than 1 second.

  5. Noncontact vibration measurements using magnetoresistive sensing elements

    Science.gov (United States)

    Tomassini, R.; Rossi, G.

    2016-06-01

    Contactless instrumentations is more and more used in turbomachinery testing thanks to the non-intrusive character and the possibility to monitor all the components of the machine at the same time. Performances of blade tip timing (BTT) measurement systems, used for noncontact turbine blade vibration measurements, in terms of uncertainty and resolution are strongly affected by sensor characteristics and processing methods. The sensors used for BTT generate pulses, used for precise measurements of turbine blades time of arrival. Nowadays proximity sensors used in this application are based on optical, capacitive, eddy current and microwave measuring principle. Pressure sensors has been also tried. This paper summarizes the results achieved using a novel instrumentation based on the magnetoresistive sensing elements. The characterization of the novel probe has been already published. The measurement system was validated in test benches and in a real jet-engine comparing different sensor technologies. The whole instrumentation was improved. The work presented in this paper focuses on the current developments. In particular, attention is given to the data processing software and new sensor configurations.

  6. Influence of temperature on Yb:YAG/Cr:YAG microchip laser operation

    Science.gov (United States)

    Šulc, Jan; Eisenschreiber, Jan; Jelínková, Helena; Nejezchleb, Karel; Å koda, Václav

    2017-02-01

    The goal of this work was an investigation of the temperature influence (in range from 80 up to 320 K) on the laser properties of Yb:YAG/Cr:YAG Q-switched diode-pumped microchip laser. This laser was based on monolith crystal (diameter 3mm) which combines in one piece an active laser part (Yb:YAG crystal, 10 at.% Yb/Y, 3mm long) and saturable absorber (Cr:YAG crystal, 1.36mm long, initial transmission 90% @ 1031 nm). The laser resonator pump mirror (HT for pump radiation, HR for generated radiation) was directly deposited on the Yb:YAG monolith part. The output coupler with reflection 55% for the generated wavelength was placed on the Cr:YAG part. The microchip laser was placed in the temperature controlled cupreous holder inside vacuum chamber of the liquid nitrogen cryostat. For Yb:YAG part longitudinal pulsed pumping (pumping pulse length 2.5 ms, rep-rate 20 Hz, power amplitude 21W) a fibre coupled (core diameter 400 μm, NA= 0:22) laser diode, operating at wavelength 933 nm, was used. The microchip laser mean output power, pulse duration, repetition rate, emission wavelength, and laser beam profile were measured in dependence on temperature. The generated pulse length was in range from 2.2 ns to 1.1 ns (FWHM) with the minimum at 230 K. The single pulse energy was peaking (0.4 mJ) at 180 K. The highest peak power (325 kW) was obtained at 220 K. The highest pulse repetition rate (38 kHz) and output mean power (370mW) was reached for temperature 80 K.

  7. Hyperfine structure investigations for the odd-parity configuration system in atomic holmium

    Science.gov (United States)

    Stefanska, D.; Furmann, B.

    2018-02-01

    In this work new experimental results of the hyperfine structure (hfs) in the holmium atom are reported, concerning the odd-parity level system. Investigations were performed by the method of laser induced fluorescence in a hollow cathode discharge lamp on 97 spectral lines in the visible part of the spectrum. Hyperfine structure constants: magnetic dipole - A and electric quadrupole - B for 40 levels were determined for the first time; for another 21 levels the hfs constants available in the literature were remeasured. Results for the A constants can be viewed as fully reliable; for B constants further possibilities of improving the accuracy are considered.

  8. Magnetic x-ray scattering studies of holmium using synchro- tron radiation

    International Nuclear Information System (INIS)

    Gibbs, D.; Moncton, D.E.; D'Amico, K.L.; Bohr, J.; Grier, B.H.

    1985-01-01

    We present the results of magnetic x-ray scattering experiments on the rare-earth metal holmium using synchrotron radiation. Direct high-resolution measurements of the nominally incommensurate magnetic satellite reflections reveal new lock-in behavior which we explain within a simple spin-discommensuration model. As a result of magnetoelastic coupling, the spin-discommensuration array produces additional x-ray diffraction satellites. Their observation further substantiates the model and demonstrates additional advantages of synchrotron radiation for magnetic-structure studies

  9. Diode-Pumped Thulium (Tm)/Holmium (Ho) Composite Fiber 2.1-Micrometers Laser

    Science.gov (United States)

    2015-09-01

    Schematic of the 800-nm diode pumped Tm/Ho composite fiber laser 8 Under quasi-continuous wave (Q- CW ) pumping conditions of 1-ms duration and a...Fig. 9 (Top) Schematic of the 800-nm diode -pumped Tm/Ho composite fiber laser with outcoupler. (Left) Q- CW laser performance of the Tm/Ho composite...ARL-TR-7452 ● SEP 2015 US Army Research Laboratory Diode -Pumped Thulium (Tm)/Holmium (Ho) Composite Fiber 2.1-μm Laser by G

  10. Holmium Laser Enucleation of the Prostate and Iatrogenic Arteriovenous Fistula Treated by Superselective Arterial Embolization

    Directory of Open Access Journals (Sweden)

    Anastasios D. Asimakopoulos

    2016-01-01

    Full Text Available Iatrogenic pelvic pseudoaneurysm with concomitant arteriovenous fistula has been described as a rare and challenging complication, which may occur during transurethral resection of the prostate. We provide the first report of this complication after holmium laser enucleation of the prostate for the treatment of benign prostatic hyperplasia. The attempt to control the bleeding by conversion to open surgery and placement of haemostatic stitches into the prostatic fossa failed. Angiography with superselective arterial embolization proved to be a modern, quick, safe, and efficient treatment of this uncommon complication.

  11. Evaluation of samarium-153 and holmium-166-EDTMP in the normal baboon model

    Energy Technology Data Exchange (ETDEWEB)

    Louw, W.K.A.; Dormehl, I.C.; Rensburg, A.J. van; Hugo, N.; Alberts, A.S.; Forsyth, O.E.; Beverley, G.; Sweetlove, M.A.; Marais, J.; Loetter, M.G.; Aswegen, A. van

    1996-11-01

    Bone-seeking radiopharmaceuticals such as ethylenediaminetetramethylene phosphonate (EDTMP) complexes of samarium-153 and holmium-166 are receiving considerable attention for therapeutic treatment of bone metastases. In this study, using the baboon experimental model, multicompartmental analysis revealed that with regard to pharmacokinetics, biodistribution, and skeletal localisation, {sup 166}Ho-EDTMP was significantly inferior to {sup 153}Sm-EDTMP and {sup 99m}Tc-MDP. A more suitable {sup 166}Ho-bone-seeking agent should thus be sought for closer similarity to {sup 153}Sm-EDTMP to exploit fully the therapeutic potential of its shorter half-life and more energetic beta radiation.

  12. Specific heat of holmium and YNi2B2C. Criticalbehaviour and superconducting properties

    International Nuclear Information System (INIS)

    Bekkali, Abdelhakim

    2010-01-01

    Object of the thesis is the study of the specific heat of holmium and YNi 2 B 2 C in the temperature ranges from 50 to 200 KI respectively from 380 mK to 20 K in magnetic fields up to 9 T. In the present thesis the criticalbehaviour of YNi 2 B 2 C and properties of the superconducting state of tne non-magnetic rare-earth nickel borocarbide YNi 2 B 2 C are studied by means of a self-developed measurement apparatur of the specific heat using the quasi-adiabatic heating-pulse method as well as of holmium by means of the relaxation method. In this thesis reliable statements about the critical exponents on monocrystalline holmium could be made. The study on holmium proves that the critical behaviour of the specific heats cannot be described in the framework of the predictions of the chiral universality classes. By means of measurements of the specific heat in this thesis could be confirmed that YNi 2 B 2 C is a multiband superconductor. The positive curvature of the boundary line below T c in the phase diagram yields a first hint to the many-band character of YNI 2 B 2 C. In the zero-field the electronic specific heat in the superconducting state c es (T) can be not explained in the framework of the pure BCS theory. At low temperatures a residual contribution by normally conducting electrons could be detected, which hints to a not completely opened energy gap. A possible explanation would be that a band (or several bands) with low charge-carrier concentration not contribute to the superconductivity. This result agrees with de Haas-van Alphen measurements on isostructural superconducting LuNi 2 B 2 C monocrystals, which suggest the many-band character of the superconductivity as well as a vanishing energy gap in one band. The fluctuation behaviour of the specific heat of YNi 2 B 2 C in the neighbourhood of the superconducting-normally conducting transition agrees well with that of the 3D-XY model. [de

  13. Endoscopic removal of a proximal urethral stent using a holmium laser: Case report and literature review

    Directory of Open Access Journals (Sweden)

    Francisco Botelho

    2012-01-01

    Full Text Available Urethral stents were initially developed for the management of urethral strictures and obstructive voiding disorders in select patients. Urethral stent complications are common and may require stent explantation, which is often quite challenging. We present our experience with endoscopic removal of an encrusted UroLume proximal urethral stent in a 72-year-old male using a holmium laser. The literature on various management options and outcomes for urethral stent removal is reviewed. Endoscopic removal of proximal urethral stents is feasible and safe and should be considered as the primary treatment option in patients requiring stent extraction.

  14. Evidence for a devil's staircase in holmium produced by an applied magnetic field

    International Nuclear Information System (INIS)

    Cowley, R.A.; Jehan, D.A.; McMorrow, D.F.; McIntyre, G.J.

    1991-01-01

    The magnetic structure of holmium has been studied using neutron diffraction when a magnetic field is applied along the c axis. The field has the effect of suppressing the onset of the commensurate cone phase found at low temperatures in zero field, and instead produces a series of spin-slip structures. In contrast to the zero-field diffraction experiments, where a continuous variation of the magnetic wave vector q was observed, we find that below ∼15 K the wave vector q is always commensurate and forms a devil's staircase with increasing field

  15. Nd: YAG laser in art works restoration

    International Nuclear Information System (INIS)

    Flores, T.; Ponce, L.; Arronte, M.; Moreno, B.; Fernandez, M.; Garcia, C.

    1998-01-01

    Laser cleaning in works of art has a number of advantages over traditional techniques of restoration. In this article, the technique used and the physical mechanisms that explain the process of ablation of pollutants are described. The results obtained in the cleaning of statues of marble and alabaster are exposed as well as oil-painting restoration. In this last specific case, the Nd: YAG laser is used with successful results. (Author) 6 refs

  16. CTE:YAG laser applications in dentistry

    Science.gov (United States)

    Shori, Ramesh K.; Fried, Daniel; Featherstone, John D. B.; Kokta, Milan R.; Duhn, Clifford W.

    1998-04-01

    The suitability of CTE:YAG laser radiation was investigated for caries preventive laser treatments and caries ablation. Although, CTE:YAG laser radiation at 2.69 micrometer is less highly absorbed by dental hard tissues than other erbium laser wavelengths, namely 2.79 and 2.94 micrometer, it can readily be transmitted through a conventional low hydroxyl fiber with minimal loss. These studies show that reasonable ablation rates and efficiencies are obtainable with both free running (200 microseconds) and Q-switched (100 ns) laser pulses on both dentin and enamel with the application of a relatively thick layer of water to the tissue surface. The water served to remove tissue char and debris from the ablation site leaving a clean crater. However, mechanical forces produced during the energetic ablative process resulted in peripheral mechanical damage to the tissue. Surface dissolution studies on enamel indicated that CTE:YAG radiation inhibited surface dissolution by organic acid by 60 - 70% compared to unirradiated controls, albeit, at fluences an order of magnitude higher than those required for CO2 laser radiation. This layer system may be suitable for dental hard tissue applications if mechanical damage can be mitigated. This work was supported by NIH/NIDR Grants R29DE12091 and R01DE09958.

  17. A Visualization Method for Corrosion Damage on Aluminum Plates Using an Nd:YAG Pulsed Laser Scanning System.

    Science.gov (United States)

    Lee, Inbok; Zhang, Aoqi; Lee, Changgil; Park, Seunghee

    2016-12-16

    This paper proposes a non-contact nondestructive evaluation (NDE) technique that uses laser-induced ultrasonic waves to visualize corrosion damage in aluminum alloy plate structures. The non-contact, pulsed-laser ultrasonic measurement system generates ultrasonic waves using a galvanometer-based Q-switched Nd:YAG laser and measures the ultrasonic waves using a piezoelectric (PZT) sensor. During scanning, a wavefield can be acquired by changing the excitation location of the laser point and measuring waves using the PZT sensor. The corrosion damage can be detected in the wavefield snapshots using the scattering characteristics of the waves that encounter corrosion. The structural damage is visualized by calculating the logarithmic values of the root mean square (RMS), with a weighting parameter to compensate for the attenuation caused by geometrical spreading and dispersion of the waves. An intact specimen is used to conduct a comparison with corrosion at different depths and sizes in other specimens. Both sides of the plate are scanned with the same scanning area to observe the effect of the location where corrosion has formed. The results show that the damage can be successfully visualized for almost all cases using the RMS-based functions, whether it formed on the front or back side. Also, the system is confirmed to have distinguished corroded areas at different depths.

  18. Use of the Moses Technology to Improve Holmium Laser Lithotripsy Outcomes: A Preclinical Study.

    Science.gov (United States)

    Elhilali, Mostafa M; Badaan, Shadie; Ibrahim, Ahmed; Andonian, Sero

    2017-06-01

    To evaluate in vitro and in vivo effects of Moses technology in Holmium laser and to compare it with the Regular mode in terms of lithotripsy efficiency and laser-tissue interactions. The Lumenis ® Pulse™ P120H holmium laser system together with Moses D/F/L fibers were used to compare the Regular mode with the Moses modes in stone retropulsion by using a high-speed camera, and stone ablation efficiency. In addition, a porcine ureteroscopy model was used to assess stone fragmentation and dusting as well as laser-tissue interaction with the ureteral wall. After a laser pulse, in vitro stone displacement experiments showed a significant reduction in retropulsion when using the Moses mode. The stone movement was reduced by 50 times at 0.8 J and 10 Hz (p technology resulted in more efficient laser lithotripsy, in addition to significantly reduced stone retropulsion, and displayed a margin of safety that may result in a shorter procedural time and safer lithotripsy.

  19. Laparoscopy-assisted micropercutaneous choledocholithotripsy with holmium laser in a cholecystectomized patient: an initial report.

    Science.gov (United States)

    Gökçen, Kaan; Atabey, Mustafa; Gökçen, Pınar; Gökçe, Gökhan

    2017-12-01

    We present a novel minimally invasive technique, laparoscopy-assisted micropercutaneous choledocholithotripsy, for choledocholithiasis that cannot be treated with other endoscopic techniques. This technique includes standard laparoscopic exploration of the common bile duct, combined with an all-seeing needle and holmium laser lithotripsy. As is known, an all-seeing needle is used in micropercutaneous nephrolithotomy for middle-sized renal stones. In this technique, an all-seeing needle was inserted into the dilatated common bile duct under laparoscopic vision and then a lithotripsy procedure was performed with a holmium laser behind the biliary stent. A cholecystectomized female patient with a 21-mm stone in the common bile duct who previously underwent an unsuccessful endoscopic retrograde cholangiopancreatography procedure was operated on in our service with laparoscopy-assisted micropercutaneous choledocholithotomy without a T-tube. This novel procedure was completed uneventfully and the patient was discharged without any complications. In the future, this procedure will hopefully be a treatment modality in choledocholithiasis that cannot be treated by other minimally invasive techniques.

  20. Laser-diode pumped Nd:YAG lasers; Laser diode reiki Nd:YAG lasear

    Energy Technology Data Exchange (ETDEWEB)

    Yuasa, H.; Akiyama, Y.; Nakayama, M. [Toshiba Corp., Tokyo (Japan)

    2000-04-01

    Laser-diode pumped Nd:YAG lasers are expected to be applied to laser processing fields such as welding, cutting, drilling, and marking due to their potential for high efficiency and compactness. We are designing and developing laser-diode pumped Nd:YAG lasers using numerical analysis simulation techniques such as ray tracing and thermal analysis. We have succeeded in achieving a laser power of more than 3 kW with 20% efficiency, which is the best ever obtained. In addition, we have developed a laser-diode pumped green laser by second harmonic generation, for precision machining on silicon wafers. (author)

  1. Noncontact evaluation for interface states by photocarrier counting

    Science.gov (United States)

    Furuta, Masaaki; Shimizu, Kojiro; Maeta, Takahiro; Miyashita, Moriya; Izunome, Koji; Kubota, Hiroshi

    2018-03-01

    We have developed a noncontact measurement method that enables in-line measurement and does not have any test element group (TEG) formation. In this method, the number of photocarriers excited from the interface states are counted which is called “photocarrier counting”, and then the energy distribution of the interface states density (D it) is evaluated by spectral light excitation. In our previous experiment, the method used was a preliminary contact measurement method at the oxide on top of the Si wafer. We developed, at this time, a D it measurement method as a noncontact measurement with a gap between the probes and the wafer. The shallow trench isolation (STI) sidewall has more localized interface states than the region under the gate electrode. We demonstrate the noncontact measurement of trapped carriers from interface states using wafers of three different crystal plane orientations. The demonstration will pave the way for evaluating STI sidewall interface states in future studies.

  2. CW laser properties of Nd:GdYAG, Nd:LuYAG, and Nd:GdLuAG mixed crystals

    Science.gov (United States)

    Di, J. Q.; Xu, X. D.; Li, D. Z.; Zhou, D. H.; Wu, F.; Zhao, Z. W.; Xu, J.; Tang, D. Y.

    2011-10-01

    Three mixed crystals, Nd:GdYAG, Nd:LuYAG, and Nd:GdLuAG, were grown by Czochralski method. We report the continuous-wave (CW) Nd:GdYAG, Nd:LuYAG, and Nd:GdLuAG laser operation under laser diode pumping. The maximum output powers are 4.11, 5.31, and 7.47 W, with slope efficiency of 73.0, 55.3, and 57.1%, respectively. With replacing Lu3+ or Y3+ ions with large Gd3+ ions, the pump efficiency increases.

  3. The possibility of clinical application of the solid state lasers: Nd:YAG, Ho:YAG, and Er:YAG in otolaryngology - head and neck surgery

    Science.gov (United States)

    Tomaszewska, M.; Kukwa, A.; Tulibacki, M.; Wójtowicz, P.; Olędzka, I.; Jeżewska, E.

    2007-02-01

    The purpose of this study was to summarize our experiences in clinical application of Nd:YAG, Ho:YAG and Er:YAG in otolaryngology- head and neck surgery. Choosing the laser type and parameters for the particular procedures was based on our previous research on tissue effects of those lasers. During the period of 1993-2006 we performed 3988 surgical procedures with the Nd:YAG laser. Over 87% of those were made for the nasal cavity pathologies as polyps, hyperplasia of inferior nasal turbinate, granulation tissue, postoperative adhesions, vascular malformations, under the local anesthesia conditions. In our experience Nd:YAG laser gives the possibility of good clinical control and low risk of side effects for disorders of high recurrence and frequent interventions necessity, as nasal polyps or respiratory papillomatosis. Nd:YAG assisted uvulopalatoplasty gives an interesting alternative for surgical procedures for snoring and slight/mild OSA-recognized patients. Due to its good hemostatic properties, it is a perfect tool for removal of the chemodectoma from meddle ear. During the period of 1995-2006 we performed 229 surgical procedures with the Ho:YAG laser, mostly for larynx pathologies (adhesion and scar tissue removal). In our experience Ho:YAG laser can serve as a precise laser knife for both soft and bony tissue. The ER:YAG laser still remain under clinical trial. Since 2001 year we performed 24 procedures of removing stone deposits from salivary glands. We believe it may become a promising method to cope with sialolithiasis which allows for glandule function preservation. All of the laser types mentioned above, can be easily coupled with endoscopes, what makes them available for all of the head and necklocalized disorders.

  4. High power YAG laser cutting; Koshutsuryoku YAG laser ni yoru setsudan gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Owaki, K. [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    1998-08-01

    This paper describes features of high power YAG cutting. The optical fiber transmission YAG laser machining system has some advantages in which optical path length compensation unit is not required and measures for low power loss and dust are not required, when compared with the CO2 laser system. Its application to the cutting of stainless steel plates has attracted attention. Cutting tests of SUS304 were conducted using high power YAG laser. Cutting of SUS304 plate with a thickness of 40 mm could be successfully done at the power of 3.5 kW. Cutting tests of SUS304 pipes with a thickness of 8 mm in water under the depth of 20 m were also conducted using air as assist gas at the power of 2.5 kW. Excellent results were obtained without scale deposition. For the tests by the composite beam using 3 kW and 4 kW systems, SUS304 plate with a thickness of 50 mm could be cut at the cutting speed of 0.1 m/min. Laser cutting of pipes from the internal surface was conducted using a newly developed small machining head which can rotate in the peripheral direction. Excellent quality for welding was confirmed. Cutting speed and plate thickness were improved by combining water jet cutter and YAG laser unit. 6 refs., 10 figs.

  5. Continuous control systems for non-contact ECG

    Science.gov (United States)

    Kodkin, Vladimir L.; Yakovleva, Galina V.; Smirnov, Alexey S.

    2017-03-01

    South Ural State University is still conducting the research work dedicated to innovations in biomedicine. Development of system for continuous control and diagnosis of the functional state in large groups of people is based on studies of non-contact ECG recording reported by the authors at the SPIE conference in 2016. The next stage of studies has been performed this year.

  6. Non-contact finger vein acquisition system using NIR laser

    Science.gov (United States)

    Kim, Jiman; Kong, Hyoun-Joong; Park, Sangyun; Noh, SeungWoo; Lee, Seung-Rae; Kim, Taejeong; Kim, Hee Chan

    2009-02-01

    Authentication using finger vein pattern has substantial advantage than other biometrics. Because human vein patterns are hidden inside the skin and tissue, it is hard to forge vein structure. But conventional system using NIR LED array has two drawbacks. First, direct contact with LED array raise sanitary problem. Second, because of discreteness of LEDs, non-uniform illumination exists. We propose non-contact finger vein acquisition system using NIR laser and Laser line generator lens. Laser line generator lens makes evenly distributed line laser from focused laser light. Line laser is aimed on the finger longitudinally. NIR camera was used for image acquisition. 200 index finger vein images from 20 candidates are collected. Same finger vein pattern extraction algorithm was used to evaluate two sets of images. Acquired images from proposed non-contact system do not show any non-uniform illumination in contrary with conventional system. Also results of matching are comparable to conventional system. We developed Non-contact finger vein acquisition system. It can prevent potential cross contamination of skin diseases. Also the system can produce uniformly illuminated images unlike conventional system. With the benefit of non-contact, proposed system shows almost equivalent performance compared with conventional system.

  7. Contact and Non-contact Measurements of Grinding Pins

    Directory of Open Access Journals (Sweden)

    Magdziak Marek

    2015-01-01

    Full Text Available The paper presents the results of contact and non-contact measurements of external profiles of selected grinding pins. The measurements were conducted in order to choose the appropriate measuring technique in the case of the considered measurement task. In the case of contact measurements the coordinate measuring machine ACCURA II was applied. The used coordinate measuring machine was equipped with the contact scanning probe VAST XT and the Calypso inspection software. Contact coordinate measurements were performed by using of different measurement strategies. The applied strategies included different scanning velocities and distances between measured points. Non-contact measurements were conducted by means of the tool presetter produced by the Mahr company. On the basis of gained results the guidelines concerning measurements of grinding pins were formulated. The measurements of analyzed grinding pins performed by means of the non-contact measuring system are characterized by higher reproducibility than the contact measurements. The low reproducibility of contact measurements may be connected with the inaccuracy of the selected coordinate measuring machine and the measuring probe, the measurement parameters and environmental conditions in the laboratory where the coordinate measuring machine is located. Moreover, the paper presents the possible application of results of conducted investigations. The results of non-contact measurements can be used in the simulation studies of grinding processes. The simulations may reduce the costs of machining processes.

  8. Novel method for noncontact measurement of particle temperatures

    NARCIS (Netherlands)

    Wagenaar, B.M.; Meijer, R.; Kuipers, J.A.M.; van Swaaij, W.P.M.

    1995-01-01

    A nonintrusive temperature measurement technique is developed for noncontact measurement of the temperature of single particles with <200 µm dia. It is based on the temperature dependence of the fluorescence spectrum resulting from irradiation of a certain phosphor mixture with UV light by applying

  9. Novel method for noncontact measurement of particle temperatures

    NARCIS (Netherlands)

    Wagenaar, B.M.; Wagenaar, B.M.; Meijer, R.; Kuipers, J.A.M.; van Swaaij, Willibrordus Petrus Maria

    1995-01-01

    A nonintrusive temperature measurement technique is developed for noncontact measurement of the temperature of single particles with < 200 m dia. It is based on the temperature dependence of the fluorescence spectrum resulting from irradiation of a certain phosphor mixture with UV light by applying

  10. Non-contact remote monitoring technique of reactor structural elements

    International Nuclear Information System (INIS)

    Inoue, Hideo; Mori, Kazuo; Ozawa, Norimitsu; Akedo, Jun; Seimiya, Koichi; Chikamori, Kunio; Umezawa, Akihiko

    1998-01-01

    This study aims at development of technique to measure and estimate, at high precision, fine machining scratch, crack and so on formed on grinding tubular elements, especially inner faces of small diameter tube at an optical mirror grade, and at establishment of estimation technique on reliability and soundness of the tubular elements. In this fiscal year, on optical type non-contact monitoring technique, investigations on optical illumination condition and holding accuracy required for the non-contact holding mechanism were conducted by using a sensor head trially produced in 1995 fiscal year. And, in order to realize a high precision non-contact holding in a tube of optical detection system to upgrade static holding properties (holding stiffness, holding attitude, and so on) of pneumatic type inner tube non-contact holding mechanism, realization of increase in supplying air pressure and experiments using a holding mechanism to increase pore numbers of air injecting nozzle were conducted. And, on materials surface technique, effect of difference in pre-machining method (cutting and bright annealing) at inner face of small diameter stainless tube on their smooth machining property was examined. (G.K.)

  11. Lande gJ factors for even-parity electronic levels in the holmium atom

    Science.gov (United States)

    Stefanska, D.; Werbowy, S.; Krzykowski, A.; Furmann, B.

    2018-05-01

    In this work the hyperfine structure of the Zeeman splitting for 18 even-parity levels in the holmium atom was investigated. The experimental method applied was laser induced fluorescence in a hollow cathode discharge lamp. 20 spectral lines were investigated involving odd-parity levels from the ground multiplet, for which Lande gJ factors are known with high precision, as the lower levels; this greatly facilitated the evaluation of gJ factors for the upper levels. The gJ values for the even-parity levels considered are reported for the first time. They proved to compare fairly well with the values obtained recently in a semi-empirical analysis for the even-parity level system of Ho I.

  12. Development of phosphate glass microspheres containing holmium for selective internal radiotherapy

    International Nuclear Information System (INIS)

    Barros Filho, Eraldo Cordeiro

    2016-01-01

    The selective internal radiotherapy is an alternative for some kinds of cancer as the hepatocellular carcinoma (HCC) or primary liver cancer treatment. In this treatment, glass or polymer microspheres containing radionuclides inside their structure are introduced in the liver through hepatic artery and trapped at the arterioles that feed the tumor. In this work, the development of phosphate glasses containing holmium for production of microspheres and their application in Brazil are proposed. The developed glasses presented suitable chemical durability, density of 2,7(3) g/cm 3 , high thermal stability and the impurities contained therein do not preclude the treatment. The microspheres were produced by the flame method and the gravitational fall method, and were characterized by means of several techniques to evaluate shape, average particle size, activity and biocompatibility suitable for selective internal radiotherapy. Based in the main results, the submission to in vivo tests is proposed. (author)

  13. High power operation of cladding pumped holmium-doped silica fibre lasers.

    Science.gov (United States)

    Hemming, Alexander; Bennetts, Shayne; Simakov, Nikita; Davidson, Alan; Haub, John; Carter, Adrian

    2013-02-25

    We report the highest power operation of a resonantly cladding-pumped, holmium-doped silica fibre laser. The cladding pumped all-glass fibre utilises a fluorine doped glass layer to provide low loss cladding guidance of the 1.95 µm pump radiation. The operation of both single mode and large-mode area fibre lasers was demonstrated, with up to 140 W of output power achieved. A slope efficiency of 59% versus launched pump power was demonstrated. The free running emission was measured to be 2.12-2.15 µm demonstrating the potential of this architecture to address the long wavelength operation of silica based fibre lasers with high efficiency.

  14. Influence of crystallite size and temperature on the antiferromagnetic helices of terbium and holmium metal

    Energy Technology Data Exchange (ETDEWEB)

    Bick, Jens-Peter; Michels, Andreas [Universitaet des Saarlandes, D-66041 Saarbruecken (Germany); University of Luxembourg, L-1511 Luxembourg (Luxembourg); Ferdinand, Adrian; Birringer, Rainer [Universitaet des Saarlandes, D-66041 Saarbruecken (Germany); Baller, Joerg; Sanctuary, Roland [University of Luxembourg, L-1511 Luxembourg (Luxembourg); Philippi, Stefan [Leibniz Institute for Solid State and Materials Research, D-01069 Dresden (Germany); Lott, Dieter [GKSS Research Center, D-21502 Geesthacht (Germany); Balog, Sandor [Paul Scherrer Institute, CH-5232 Villigen (Switzerland); Rotenberg, Eli [Lawrence Berkeley National Laboratory, California 94720 (United States); Kaindl, Guenter [Freie Universitaet Berlin, D-14195 Berlin-Dahlem (Germany); Doebrich, Kristian M. [Freie Universitaet Berlin, D-14195 Berlin-Dahlem (Germany); Max-Born-Institut, D-12489 Berlin (Germany)

    2011-07-01

    We report on the results of grain-size and temperature-dependent magnetization, specific-heat, neutron-scattering, and angle-resolved photoelectron spectroscopy (ARPES) experiments on the heavy rare-earth metals terbium and holmium, with particular emphasis on the temperature regions where the helical antiferromagnetic phases exist. In contrast to Ho, we find that the helical structure in Tb is relative strongly affected by microstructural disorder, specifically, it can no longer be detected for the smallest studied grain size of D=18 nm. Moreover, in coarse-grained Tb a helical structure persists even in the ferromagnetic regime, down to about T=215 K, in agreement with the ARPES data, which reveal a nesting feature of the Fermi surface at the L point of the Brillouin zone at T=210 K.

  15. Holmium-doped fluorotellurite microstructured fibers for 2.1 μm lasing.

    Science.gov (United States)

    Yao, Chuanfei; He, Chunfeng; Jia, Zhixu; Wang, Shunbin; Qin, Guanshi; Ohishi, Yasutake; Qin, Weiping

    2015-10-15

    Holmium (Ho3+)-doped fluorotellurite microstructured fibers based on TeO2-BaF2-Y2O3 glasses are fabricated by using a rod-in-tube method. By using a 1.992 μm fiber laser as the pump source, lasing at 2.077 μm is obtained from a 27 cm long Ho3+-doped fluorotellurite microstructured fiber. The maximum unsaturated power is about 161 mW and the corresponding slope efficiency is up to 67.4%. The influence of fiber length on lasing at 2.1 μm is also investigated. Our results show that Ho3+-doped fluorotellurite microstructured fibers are promising gain media for 2.1 μm laser applications.

  16. Synthesis and optical properties of antimony oxide glasses doped with holmium trioxide

    Energy Technology Data Exchange (ETDEWEB)

    Raghunatha, S.; Eraiah, B., E-mail: eraiah@rediffmail.com [Department of physics, Bangalore University, Bengaluru – 560 056. India (India)

    2016-05-06

    Holmium doped lithium-antimony-lead borate glasses having 1 mol% AgNO{sub 3} with composition 50B{sub 2}O{sub 3}-20PbO-25Sb{sub 2}O{sub 3}-5Li{sub 2}O have been prepared using single step melt quenching technique. The XRD spectrum confirms amorphous nature of glasses. The optical absorbance studies were carried out on these glasses. The optical direct band gap energies were found to be in the range of 3.10 eV to 3.31 eV and indirect band gap energies were found to be in the range of 2.28 eV to 3.00 eV. The refractive indexes have been calculated by using Lorentz-Lorenz formula and the calculated values in the range of 2.31 to 2.37.

  17. Study of intraarticular application of 166-Holmium IHPP in healthy hares

    International Nuclear Information System (INIS)

    Szentesi, M.; Koernyei, J.; Antalffi, M.; Toerkoe, J.; Toth, G.Y.; Janoki, G.Y.; Balogh, L.

    2002-01-01

    Radiosynoviorthesis non invasive therapy in rheumatoid arthritis is an alternative of surgical synovectomy. This method was applied first by Fellinger in 1952, and since then it has been practiced all over the world. The leakage of traditionally applied isotopes is cca. 4-10%, and the whole body dose is 10 rads. The objective of our work is to produce a nuclear medication with a minimum radioactive load, of short half-life and ideal molecule size for the treatment of radiosynoviorthesis / 166- Holmium IHPP / and the study of its effect on healthy hares. The first results have been already reported on previously. 166-Holmium IHPP has the features of: half-life of 26.9 hr, the maximum soft-tissue penetration of a beta particle 1.84 MeV, emitted from 166-Ho 8.4 mm. With an average of 3.3 mm. Methods applied: Biodistribution analysis, gamma camera analysis, biochemical and histological tests with photo- and electro microscope were carried out on healthy New Zealand hares 6, 24, 72, 168 hours after radiosynoviorthesis. Results: All the testing methods applied showed that 97 /96,1-98,2/ % remained on the spot of the injection and the 2/3 of the small percentage released leakage: is excreted by the liver and the other 1/3 of it with the urine.The hematological and biochemical parameters did not show differences. During histological examination moderate level acute radioarthritis in the knee joint treated was observed (6-24 hours after the injection), then moderate level subacute radioarthritis with slight degeneration in the synovial membrane and in the synovial fluid. It was only the electro microscopic examination that did show a minimal degeneration in the cartilage and in the menisci, but it got regenerated in 168 hours. Conclusion: The examination carried out has proved that 166-Ho -IHPP can be effectively applied in radiosynoviorthesis. Clinical testing has started

  18. Microspheres of poly(ε-caprolactone) loaded Holmium-165: morphology and thermal degradation behavior

    International Nuclear Information System (INIS)

    Geraldes, Adriana Napoleao; Miyamoto, Douglas Massao; Lira, Raphael Arivar de; Osso Junior, Joao Alberto; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de

    2011-01-01

    Polycaprolactone (PCL), being one of the most important biocompatible and biodegradable aliphatic polyester, provides many potential biomedical. The preparation of biodegradable materials, polymer-based microspheres, is being developed by our group and the goal is to prepare and label with Ho-165 different polymer-based microspheres. The use of radionuclide-loaded microspheres is a promising treatment of liver malignancies. PCL microspheres can be loaded with holmium acetylacetonate (HoAcAc). PCL and PCL/HoAcAc microspheres were prepared by an emulsion solvent extraction/evaporation technique. The PCL/ HoAcAc microspheres were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP to radionuclide activation. Gamma irradiation was performed at 25 and 50 kGy doses. The microspheres were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and con focal laser scanning microscopy (CLSM). In the CLSM images were observed emission in 488 nm characteristic of holmium. The SEM surface image of PCL/HoAcAc microspheres showed more roughness than PCL microspheres. TG of PCL/HoAcAc microspheres showed a substantial weight loss above 200 degree C, indicating decomposition of HoAcAc. The residual weight indicates the presence of Ho 2 O 3 . Gamma irradiation at 25 and 50 kGy doses had no effect on the PCL/HoAcAc microspheres, which indicates that the chemical composition of the microspheres had not change. (author)

  19. Microspheres of poly({epsilon}-caprolactone) loaded Holmium-165: morphology and thermal degradation behavior

    Energy Technology Data Exchange (ETDEWEB)

    Geraldes, Adriana Napoleao; Miyamoto, Douglas Massao; Lira, Raphael Arivar de; Osso Junior, Joao Alberto; Nascimento, Nanci; Azevedo, Mariangela de Burgos M. de [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Polycaprolactone (PCL), being one of the most important biocompatible and biodegradable aliphatic polyester, provides many potential biomedical. The preparation of biodegradable materials, polymer-based microspheres, is being developed by our group and the goal is to prepare and label with Ho-165 different polymer-based microspheres. The use of radionuclide-loaded microspheres is a promising treatment of liver malignancies. PCL microspheres can be loaded with holmium acetylacetonate (HoAcAc). PCL and PCL/HoAcAc microspheres were prepared by an emulsion solvent extraction/evaporation technique. The PCL/ HoAcAc microspheres were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP to radionuclide activation. Gamma irradiation was performed at 25 and 50 kGy doses. The microspheres were evaluated by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TG), Fourier transformed infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and con focal laser scanning microscopy (CLSM). In the CLSM images were observed emission in 488 nm characteristic of holmium. The SEM surface image of PCL/HoAcAc microspheres showed more roughness than PCL microspheres. TG of PCL/HoAcAc microspheres showed a substantial weight loss above 200 degree C, indicating decomposition of HoAcAc. The residual weight indicates the presence of Ho{sub 2}O{sub 3}. Gamma irradiation at 25 and 50 kGy doses had no effect on the PCL/HoAcAc microspheres, which indicates that the chemical composition of the microspheres had not change. (author)

  20. Holmium laser assisted ′anatomical′ enucleation of adenoma of benign hyperplasia of prostate

    Directory of Open Access Journals (Sweden)

    Shivadeo S Bapat

    2006-01-01

    Full Text Available Aims: To present our technique of Holmium Laser assisted "ANATOMICAL" enucleation of the benign prostatic adenoma (HoLEP in 219 patients. Procedure is based on the principle of digital enucleation of the adenoma from its surgical capsule, but performed entirely by perurethral endoscopic technique assisted by Holmium Laser. Materials and Methods: From March 2001 to November 2004, 219 patients under went HoLEP. After the initial cuts from bladder neck to verumontanum at 5 and 7 o′clock position, capsule is identified. The beak of the resectoscope sheath was inserted in the plane between the capsule and the adenoma and the adenoma was physically pushed away towards the urethra from the capsule. Laser was used to coagulate the bleeders, to cut the mucosal attachments and tough stromal tissue. Procedure was repeated for median and two lateral lobes. There was minimal bleeding and fluid absorption. Complications were few. Results: In 206 cases successful enucleation of the adenoma was carried out. First 13 cases formed part of the learning curve and were completed by standard transurethral resection of prostate (TURP. IPSS score dropped from average of 23 to 8 and peak flow improved from 20. No patient had postoperative urinary incontinence or stricture. Conclusions: HoLEP is an effective alternative to TURP. Ultimate end results replicate the end results of open enucleation of BPH without its morbidity and have all the advantages of endoscopic surgery. It offers distinct advantages over standard TURP as the incidence of blood transfusion and fluid absorption are greatly minimized.

  1. Separation of holmium (III) from aqueous chloride medium by Amberlite IRC748

    International Nuclear Information System (INIS)

    Vijayalakshmi, R.; Anitha, M.; Singh, D.K.; Chakravartty, J.K.

    2016-01-01

    High purity holmium finds applications in nuclear reactors as control rod, rare earth based magnetic alloys, lasers, medical applications, etc. Holmium belongs to the heavier group of rare earths and its content is very less (<0.5%) in Monazite mineral, hence its recovery from various potential sources becomes essential. Ion exchange technique is a well known method for effective separation, purification, recovery, and concentration of metal ions from lean aqueous solutions. It has also been widely used for separation and purification of rare earths. In the present investigation application of Amberlite IRC748, a chelating type of resin containing iminodiacetic acid functional group for separation of Ho(III) was explored. The effects of various parameters such as pH, contact time, weight of resin, initial metal concentration and temperature on the adsorption characteristics of Ho(III) were investigated in detail. The loading of Ho(III) ion onto resin increased with increasing the initial concentration. The adsorption was strongly dependent on pH of the medium with enhanced adsorption as the pH turned from 1 to 4. In the batch system, the Amberlite IRC748 resin exhibited the highest Ho(III) ion uptake as 180 mg/g at 298 K, at an initial pH value of 4. The adsorption data gave good fit with Langmuir isotherm which was better than the Freundlich curve. The thermodynamic parameters such as ΔH, ΔS and ΔG were evaluated from the temperature variation data. Negative value of ΔH (-11.5 kJ/mole), indicated that the adsorption of Ho(III) ion onto Amberlite resin was exothermic in nature. ΔS was found to be 5.52 J/mole/K. Kinetic study indicated that the adsorption data fitted the pseudo second order kinetic equation. (author)

  2. Percutaneous Transhepatic Endoscopic Holmium Laser Lithotripsy for Intrahepatic and Choledochal Biliary Stones

    International Nuclear Information System (INIS)

    Rimon, Uri; Kleinmann, Nir; Bensaid, Paul; Golan, Gil; Garniek, Alexander; Khaitovich, Boris; Winkler, Harry

    2011-01-01

    Purpose: To report our approach for treating complicated biliary calculi by percutaneous transhepatic endoscopic biliary holmium laser lithotripsy (PTBL). Patients and Methods: Twenty-two symptomatic patients (11 men and 11 women, age range 51 to 88 years) with intrahepatic or common bile duct calculi underwent PTBL. Nine patients had undergone previous gastrectomy and small-bowel anastomosis, thus precluding endoscopic retrograde cholangiopancreatography. In the other 13 patients, stone removal attempts by ERCP failed due to failed access or very large calculi. We used a 7.5F flexible ureteroscope and a 200-μm holmium laser fiber by way of a percutaneous transhepatic tract, with graded fluoroscopy, to fragment the calculi with direct vision. Balloon dilatation was added when a stricture was seen. The procedure was performed with the patient under general anaesthesia. A biliary drainage tube was left at the end of the procedure. Results: All stones were completely fragmented and flushed into the small bowel under direct vision except for one patient in whom the procedure was aborted. In 18 patients, 1 session sufficed, and in 3 patients, 2 sessions were needed. In 7 patients, balloon dilatation was performed for benign stricture after Whipple operation (n = 3), for choledochalenteric anastomosis (n = 3), and for recurrent cholangitis (n = 1). Adjunctive “balloon push” (n = 4) and “rendezvous” (n = 1) procedures were needed to completely clean the biliary tree. None of these patients needed surgery. Conclusion: Complicated or large biliary calculi can be treated successfully using PTBL. We suggest that this approach should become the first choice of treatment before laparoscopic or open surgery is considered.

  3. Magneto-optical study of holmium iron garnet Ho3Fe5O12

    Science.gov (United States)

    Kalashnikova, A. M.; Pavlov, V. V.; Kimel, A. V.; Kirilyuk, A.; Rasing, Th.; Pisarev, R. V.

    2012-09-01

    Bulk holmium iron garnet Ho3Fe5O12 is a cubic ferrimagnet with Curie temperature TC = 567 K and magnetization compensation point in the range 130-140 K. The magneto-optical data are presented for a holmium iron garnet Ho3Fe5O12 film, ˜10 μm thick, epitaxially grown on a (111)-type gadolinium-gallium garnet Gd3Ga5O12 substrate. A specific feature of this structure is that the parameters of the bulk material, from which the film was grown, closely match the substrate ones. The temperature and field dependences of Faraday rotation as well as the temperature dependence of the domain structure in zero field were investigated. The compensation point of the structure was found to be Tcomp = 127 K. It was shown that the temperature dependence of the characteristic size of domain structure diverges at this point. Based on the obtained results we established that the magnetic anisotropy of the material is determined by both uniaxial and cubic contributions, each characterized by different temperature dependence. A complex shape of hysteresis loops and sharp changes of the domain pattern with temperature indicate the presence of collinear-noncollinear phase transitions. Study of the optical second harmonic generation was carried out using 100 fs laser pulses with central photon energy E = 1.55 eV. The electric dipole contribution (both crystallographic and magnetic) to the second harmonic generation was observed with high reliability despite a small mismatch of the film and substrate parameters.

  4. Bond strength of an adhesive system irradiated with Nd:YAG laser in dentin treated with Er:YAG laser

    International Nuclear Information System (INIS)

    Malta, D A M P; De Andrade, M F; Costa, M M; Lizarelli, R F Z; Pelino, J E P

    2008-01-01

    The purpose of this in vitro study was to verify through micro tensile bond test the bond strength of an adhesive system irradiated with Nd:YAG laser in dentine previously treated with Er:YAG laser. Twenty caries free extracted human third molars were used. The teeth were divided in four experimental groups (n = 5): (G1) control group; (G2) irradiation of the adhesive system with the Nd:YAG laser; (G3) dentin treatment with Er:YAG laser; (G4) dentin treatment with Er:YAG laser followed by the irradiation of the adhesive system with Nd:YAG laser. The Er:YAG laser fluency parameter for the dentin treatment was of 60 J/cm 2 . The adhesive system was irradiated with the Nd:YAG laser with fluency of 100 J/cm 2 . Dental restorations were performed with Adper Single Bond 2/Z250. One tooth from each group was prepared for the evaluation of the adhesive interface under SEM and bond failure tests were also performed and evaluated. The statistical analysis showed statistical significant difference between the groups G1 and G3, G1 and G4, G2 and G3, and G2 and G4; and similarity between the groups G1 and G2, and G3 and G4. The adhesive failures were predominant in all the experimental groups. The SEM analysis showed an adhesive interface with features confirming the results of the mechanical tests. The Nd:YAG laser on the adhesive system did not influence the bond strength in dentin treated or not with the Er:YAG laser

  5. Simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides by second order derivative spectrophotometry

    International Nuclear Information System (INIS)

    Anbu, M.; Prasada Rao, T.; Iyer, C. S. P.; Damodaran, A. D.

    1996-01-01

    High purity individual rare earth oxides are increasingly used as major components in lasers (Y 2 O 3 ), phosphors (YVO 3 , Eu 2 O 3 ), magnetic bubble memory films (Gd 2 O 3 ) and refractive-index lenses and fibre optics (La 2 O 3 ). The determination of individual lanthanides in high purity rare earth oxides is a more important and difficult task. This paper reports the utilization of higher order derivative spectrophotometry for the simultaneous determination of dysprosium, holmium and erbium in high purity rare earth oxides. The developed procedure is simple, reliable and allows the determination of 0.001 to 0.2% of dysprosium, holmium and erbium in several rare earth. (author). 9 refs, 2 figs, 2 tabs

  6. Holmium laser vs. conventional (cold knife) direct visual internal urethrotomy for short-segment bulbar urethral stricture: Outcome analysis.

    Science.gov (United States)

    Jhanwar, Ankur; Kumar, Manoj; Sankhwar, Satya Narayan; Prakash, Gaurav

    2016-01-01

    Our goal was to analyze the outcome between holmium laser and cold knife direct visual internal urethrotomy (DVIU) for short-segment bulbar urethral stricture. We conducted a prospective study comprised of 112 male patients seen from June 2013 to December 2014. Inclusion criterion was short-segment bulbar urethral stricture (≤1.5cm). Exclusion criteria were prior intervention/urethroplasty, pan-anterior urethral strictures, posterior stenosis, urinary tract infection, and those who lost to followup. Patients were divided into two groups; Group A (n=58) included cold knife DVIU and group B (n=54) included holmium laser endourethrotomy patients. Patient followup included uroflowmetry at postoperative Day 3, as well as at three months and six months. Baseline demographics were comparable in both groups. A total of 107 patients met the inclusion criteria and five patients were excluded due to inadequate followup. Mean stricture length was 1.31 ± 0.252 cm (p=0.53) and 1.34 ± 0.251 cm in Groups A and B, respectively. Mean operating time in Group A was 16.3 ± 1.78 min and in Group B was 20.96 ± 2.23 min (p=0.0001). Five patients in Group A had bleeding after the procedure that was managed conservatively by applying perineal compression. Three patients in Group B had fluid extravasation postoperatively. Qmax (ml/s) was found to be statistically insignificant between the two groups at all followups. Both holmium laser and cold knife urethrotomy are safe and equally effective in treating short-segment bulbar urethral strictures in terms of outcome and complication rate. However, holmium laser requires more expertise and is a costly alternative.

  7. Study of non-contact measurement of the thermal expansion coefficients of materials based on laser feedback interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Fasong [The State Key Lab of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University, Beijing 100084 (China); Departments of Physics, College of Science, Beijing University of Chemical Technology, Beijing 100029 (China); Tan, Yidong; Zhang, Shulian, E-mail: zsl-dpi@mail.tsinghua.edu.cn [The State Key Lab of Precision Measurement Technology and Instrument, Department of Precision Instruments, Tsinghua University, Beijing 100084 (China); Lin, Jing; Ding, Yingchun [Departments of Physics, College of Science, Beijing University of Chemical Technology, Beijing 100029 (China)

    2015-04-15

    The noncooperative and ultrahigh sensitive length measurement approach is of great significance to the study of a high-precision thermal expansion coefficient (TEC) determination of materials at a wide temperature range. The novel approach is presented in this paper based on the Nd:YAG microchip laser feedback interferometry with 1064 nm wavelength, the beam frequency of which is shifted by a pair of acousto-optic modulators and then the heterodyne phase measurement technique is used. The sample is placed in a muffle furnace with two coaxial holes opened on the opposite furnace walls. The measurement beams are perpendicular and coaxial on each surface of the sample, the configuration which can not only achieve the length measurement of sample but also eliminate the influence of the distortion of the sample supporter. The reference beams inject on the reference mirrors which are put as possible as near the holes, respectively, to eliminate the air disturbances and the influence of thermal lens effect out of the furnace chamber. For validation, the thermal expansion coefficients of aluminum and steel 45 samples are measured from room temperature to 748 K, which proved measurement repeatability of TECs is better than 0.6 × 10{sup −6}(K{sup −1}) at the range of 298 K–598 K and the high-sensitive non-contact measurement of the low reflectivity surface induced by the oxidization of the samples at the range of 598 K–748 K.

  8. Lasing and thermal characteristics of Yb:YAG/YAG composite with atomic diffusion bonding

    Czech Academy of Sciences Publication Activity Database

    Nagisetty, Siva S.; Severová, Patricie; Miura, Taisuke; Smrž, Martin; Kon, H.; Uomoto, M.; Shimatsu, T.; Kawasaki, M.; Higashiguchi, T.; Endo, Akira; Mocek, Tomáš

    2017-01-01

    Roč. 14, č. 1 (2017), 1-6, č. článku 015001. ISSN 1612-2011 R&D Projects: GA MŠk LM2015086; GA MŠk LO1602 Institutional support: RVO:68378271 Keywords : composite Yb:YAG ceramic * atomic diffusion bonding * thermal effects Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 2.537, year: 2016

  9. Feasibility of Endovascular Radiation Therapy Using Holmium-166 Filled Balloon Catheter in a Swine Hemodialysis Fistula Model: Preliminary Results

    Energy Technology Data Exchange (ETDEWEB)

    Won, Jong Yun; Lee, Kwang Hun; Lee, Do Yun [Dept. of Radiology, Research Institute of Radiological Science, Yensei University College of Medicine, Seoul (Korea, Republic of); Kim, Myoung Soo [Dept. of Radiology, Yensei University College of Medicine, Seoul (Korea, Republic of); Kang, Byung Chul [Dept. of Radiology, Internal Medicine, EwhaWoman' s University School of Medicine, Seoul (Korea, Republic of); Kim, Seung Jung [Dept. of Internal Medicine, EwhaWoman' s University School of Medicine, Seoul (Korea, Republic of)

    2011-08-15

    To describe how to make a swine hemodialysis fistula model and report our initial experience to test the feasibility of endovascular radiation therapy with Holmium-166 filled balloon catheters. The surgical formation of arterio-venous fistula (AVF) was performed by end-to-side anastomosis of the bilateral jugular vein and carotid artery of 6 pigs. After 4 weeks, angiograms were taken and endovascular radiation was delivered to the venous side of AVF with Holmium-166 filled balloon catheters. Pigs were sacrificed 4 weeks after the radiation and AVFs were harvested for histological examination. All animals survived without any morbidity during the experimental periods. The formation of fistula on the sides of necks was successful in 11 of the 12 pigs (92%). One AVF failed from the small jugular vein. On angiograms, 4 of the 11 AVFs showed total occlusion or significant stenosis and therefore, endovascular radiation could not be performed. Of 7 eligible AVFs, five underwent successful endovascular radiation and two AVFs did not undergo radiation for the control. Upon histologic analysis, one non-radiated AVF showed total occlusion and others showed intimal thickening from the neointimal hyperplasia. Formation of the swine carotid artery-jugular vein hemodialysis fistula model was successful. Endovascular radiation using a Holmium-166 filled balloon catheter was safe and feasible.

  10. Stimulated Raman adiabatic passage in Tm3+:YAG

    International Nuclear Information System (INIS)

    Alexander, A. L.; Lauro, R.; Louchet, A.; Chaneliere, T.; Le Goueet, J. L.

    2008-01-01

    We report on the experimental demonstration of stimulated Raman adiabatic passage in a Tm 3+ :YAG crystal. Tm 3+ :YAG is a promising material for use in quantum information processing applications, but as yet there are few experimental investigations of coherent Raman processes in this material. We investigate the effect of inhomogeneous broadening and Rabi frequency on the transfer efficiency and the width of the two-photon spectrum. Simulations of the complete Tm 3+ :YAG system are presented along with the corresponding experimental results

  11. Heat treatment of transparent Yb:YAG and YAG ceramics and its influence on laser performance

    Science.gov (United States)

    Fujioka, Kana; Mochida, Tetsuo; Fujimoto, Yasushi; Tokita, Shigeki; Kawanaka, Junji; Maruyama, Momoko; Sugiyama, Akira; Miyanaga, Noriaki

    2018-05-01

    Composite transparent ceramic materials are promising for improving the performance of high-average-power lasers. A combination of room-temperature bonding via surface treatment by a fast atom beam and diffusion bonding via heating, which effectively controls the ion diffusion distance near the interface, makes the laser materials suitable for a variety of oscillator/amplifier. During the heat treatment of yttrium aluminum garnet (YAG) ceramics, the Si ions in the solid solution of the sintering aid incorporated within the grains were seen to segregate at the grain boundary, resulting in an increase of scattering sites. The number density and size of the scattering sites strongly depended on the post-heating temperature rather than the heating time. Specifically, heating at 1300 °C did not affect the transmittance of the YAG ceramic, whereas both the size and number of scattering sites substantially increased with a heat treatment at 1400 °C. The laser oscillation experiment using cryogenically-cooled Yb:YAG ceramics exhibited heating temperature dependence of the slope efficiency owing to the increasing scattering loss.

  12. Luminescence properties in the visible of Dy:YAG/YAG planar waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Klimczak, M., E-mail: m.klimczak@elka.pw.edu.p [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Malinowski, M. [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Sarnecki, J. [Institute of Electronic Materials Technology, Wolczynska 133, 01-919 Warsaw (Poland); Piramidowicz, R. [Institute of Microelectronics and Optoelectronics, Koszykowa 75, 00-662 Warsaw (Poland); Telekomunikacja Polska Research and Development Centre, Obrzezna 7, 02-691 Warsaw (Poland)

    2009-12-15

    In this work, we investigate visible emission properties of dysprosium-doped yttrium aluminum garnet (YAG) waveguides prepared by the liquid phase epitaxy (LPE) method, which allowed obtaining samples of activator concentrations ranging from 0.2 at% up to ca. 18 at%. This unique set of Dy:YAG/YAG waveguides has been carefully examined by means of highly resolved laser spectroscopy to explore the luminescence properties in the visible (yellow-blue) part of spectrum. In particular, the low-temperature absorption spectra have been recorded and analyzed, giving a more detailed information on energy levels' positions in these crystals. The concentration-dependant emission spectra and fluorescence dynamics profiles have been collected under direct excitation, enabling analysis of multi-ion processes responsible for concentration quenching. This, in turn, enabled optimization of activator concentration with respect to yellow emission efficiency. Additionally, the possible IR to visible up-conversion pathways have been discussed, giving a starting point for further investigations.

  13. Pulsed Nd-YAG laser in endodontics

    Science.gov (United States)

    Ragot-Roy, Brigitte; Severin, Claude; Maquin, Michel

    1994-12-01

    The purpose of this study was to establish an operative method in endodontics. The effect of a pulsed Nd:YAG laser on root canal dentin has been examined with a scanning electron microscope. Our first experimentation was to observe the impacts carried out perpendicularly to root canal surface with a 200 micrometers fiber optic in the presence of dye. Secondarily, the optical fiber was used as an endodontic instrument with black dye. The irradiation was performed after root canal preparation (15/100 file or 40/100 file) or directly into the canal. Adverse effects are observed. The results show that laser irradiation on root canal dentin surfaces induces a nonhomogeneous modified dentin layer, melted and resolidified dentin closed partially dentinal tubules. The removal of debris is not efficient enough. The laser treatment seems to be indicated only for endodontic and periapical spaces sterilization after conventional root canal preparation.

  14. Simulation of non-contact tonometer - Ocular response analyzer

    Directory of Open Access Journals (Sweden)

    M. Arsalan Khan

    2016-04-01

    Simultaneous explosion of ophthalmic knowledge and medical instrument, being made in the 19th century, has led to the invention of tonometers of varied designs and principles, and Non-Contact Tonometers (NCTs are among them. Glodmann Applanation Tonometer (GAT is considered the ‘gold standard’ in measuring IOP; however, IOP measurement using GAT is now known to be affected by various factors like corneal thickness, curvature and material properties as demonstrated by Khan [1]. Due to inaccuracies in measuring IOP by GAT, this ‘gold standard’ has been challenged. Therefore, the present research aims to develop a multi-parametric correction equation to determine the True Intraocular Pressure (IOPT using Non-Contact Tonometer and the current article focuses on evaluating the influence of individual parameters on IOP by NCT.

  15. Noncontact ultrasound imaging applied to cortical bone phantoms

    OpenAIRE

    Bulman, J. B.; Ganezer, K. S.; Halcrow, P. W.; Neeson, Ian

    2012-01-01

    Purpose: The purpose of this paper was to take the first steps toward applying noncontact ultrasound (NCU) to the tasks of monitoring osteoporosis and quantitative ultrasound imaging (QUS) of cortical bone. The authors also focused on the advantages of NCU, such as its lack of reliance on a technologist to apply transducers and a layer of acoustical coupling gel, the ability of the transducers to operate autonomously as specified by preprogrammed software, and the likely reduction in statisti...

  16. Non-contact fluid characterization in containers using ultrasonic waves

    Science.gov (United States)

    Sinha, Dipen N [Los Alamos, NM

    2012-05-15

    Apparatus and method for non-contact (stand-off) ultrasonic determination of certain characteristics of fluids in containers or pipes are described. A combination of swept frequency acoustic interferometry (SFAI), wide-bandwidth, air-coupled acoustic transducers, narrowband frequency data acquisition, and data conversion from the frequency domain to the time domain, if required, permits meaningful information to be extracted from such fluids.

  17. Non-contacting "snubber bearing" for passive magnetic bearing systems

    Science.gov (United States)

    Post, Richard F

    2017-08-22

    A new non-contacting magnetic "snubber" bearing is provided for application to rotating systems such as vehicular electromechanical battery systems subject to frequent accelerations. The design is such that in the equilibrium position the drag force of the snubber is very small (milliwatts). However in a typical case, if the rotor is displaced by as little as 2 millimeters a large restoring force is generated without any physical contact between the stationary and rotating parts of the snubber bearing.

  18. Non-contact tonometry in the postoperative eye.

    OpenAIRE

    Vernon, S A

    1989-01-01

    The Keeler Pulsair non-contact tonometer was compared with the Goldmann applanation tonometer in a series of 48 eyes after operation. A correlation coefficient of 0.92 (p less than 0.001) was found between the two instruments, with the Pulsair having a statistically significant tendency to overread the Goldmann slightly in this situation. The Pulsair was, however, shown to be effective in the identification of postoperative ocular hypertension with a high degree of sensitivity and specificity...

  19. Automatic Bowel Motility Evaluation Technique for Noncontact Sound Recordings

    Directory of Open Access Journals (Sweden)

    Ryunosuke Sato

    2018-06-01

    Full Text Available Information on bowel motility can be obtained via magnetic resonance imaging (MRIs and X-ray imaging. However, these approaches require expensive medical instruments and are unsuitable for frequent monitoring. Bowel sounds (BS can be conveniently obtained using electronic stethoscopes and have recently been employed for the evaluation of bowel motility. More recently, our group proposed a novel method to evaluate bowel motility on the basis of BS acquired using a noncontact microphone. However, the method required manually detecting BS in the sound recordings, and manual segmentation is inconvenient and time consuming. To address this issue, herein, we propose a new method to automatically evaluate bowel motility for noncontact sound recordings. Using simulations for the sound recordings obtained from 20 human participants, we showed that the proposed method achieves an accuracy of approximately 90% in automatic bowel sound detection when acoustic feature power-normalized cepstral coefficients are used as inputs to artificial neural networks. Furthermore, we showed that bowel motility can be evaluated based on the three acoustic features in the time domain extracted by our method: BS per minute, signal-to-noise ratio, and sound-to-sound interval. The proposed method has the potential to contribute towards the development of noncontact evaluation methods for bowel motility.

  20. Nondestructive quality assurance of ceramic filters using noncontact dynamic characterization

    Energy Technology Data Exchange (ETDEWEB)

    Yue, P.; Chen, S.E.; Nishihama, Y. [University of Alabama, Birmingham, AL (United States). Dept. of Civil & Environmental Engineering

    2005-06-01

    Ceramic candle filters are stiff cylindrical structures arranged in rosettes in a hot gas vessel. Custom-made with strong composite materials, these filters are designed to withstand heating and cooling cycles of very high temperature gradients during coal energy production processes. To ensure consistency in the manufactured filters, noncontact dynamic characterization using laser vibrometry is proposed as a factory quality control technique. To evaluate the proposed technique, a sensitivity study using both contact and noncontact vibration measurements is first conducted. The shift in natural vibration frequencies is used as a quality indicator for likely manufacturing variables. Six candle filters are tested using dynamic impact tests. Contact and noncontact results are compared with theoretical natural frequency values, which show that laser results were 'noisier' due to dropout from speckle noises. The results are used to establish the sensitivity of the technique, which indicates that dynamic characterization is a valid nondestructive testing technique for quality assurance of the ceramic filters, provided that the manufactured filters have a quality variation greater than 3.21%.

  1. The bactericidal effect of a Genius (R) Nd : YAG laser

    NARCIS (Netherlands)

    Kranendonk, A.A.; Reijden, W.A. van der; Winkelhoff, A.J. van; Weijden, G.A. van der

    PURPOSE: To evaluate the 'in vitro' bactericidal effect of the Nd:YAG laser (Genius, MØlsgaard Dental, Copenhagen, Denmark) on six periodontal pathogens. METHODS: Suspensions of six different periodontal pathogens (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella

  2. Self-mode-locked Nd3+:YAG laser

    International Nuclear Information System (INIS)

    Komarov, A K; Komarov, K P; Kuch'yanov, Aleksandr S

    2003-01-01

    Self-mode-locking was observed in a Nd 3+ :YAG laser with a negative feedback without introducing any nonlinear elements into the laser cavity. The laser generates during pumping 300 - 500-ps single pulses on an axial period. (lasers)

  3. Neodymium-YAG laser vitreolysis in sickle cell retinopathy

    Energy Technology Data Exchange (ETDEWEB)

    Hrisomalos, N.F.; Jampol, L.M.; Moriarty, B.J.; Serjeant, G.; Acheson, R.; Goldberg, M.F.

    1987-08-01

    Six patients with proliferative sickle cell retinopathy and vitreous bands were treated with the neodymium-YAG (Nd-YAG) laser to accomplish lysis of avascular traction bands or to clear the media in front of the macula. Transection of bands was possible in five of the six cases but in two of these the effect was only partial. Three cases were satisfactorily treated with the Nd-YAG laser application alone, two eventually required conventional vitreoretinal surgery, and one patient's condition stabilized despite failure of the treatment. Complications from the treatment occurred in three cases and included subretinal (choroidal) hemorrhage, preretinal hemorrhage, microperforation of a retinal vein, and focal areas of damage to the retinal pigment epithelium. Neodymium-YAG vitreolysis may be a useful modality in carefully selected patients with proliferative sickle cell retinopathy, but potentially sight-threatening complications may occur.

  4. The evaluation of tissue mass loss in the incision line of prostate with benign hyperplasia performed using holmium laser and cutting electrode.

    Science.gov (United States)

    Szewczyk, Mariusz; Jesionek-Kupnicka, Dorota; Lipiński, Marek Ireneusz; Lipinski, Piotr; Różański, Waldemar

    2014-01-01

    The aim of this study is to compare the changes in the incision line of prostatic adenoma using a monopolar cutting electrode and holmium laser, as well as the assessment of associated tissue mass and volume loss of benign prostatic hyperplasia (BPH). The material used in this study consisted of 74 preparations of prostatic adenoma obtained via open retropubic adenomectomy, with an average volume of 120.7 ml. The material obtained cut in vitro before fixation in formaldehyde. One lobe was cut using holmium laser, the other using a monopolar cutting electrode. After the incision was made, tissue mass and volume loss were evaluated. Thermocoagulation changes in the incision line were examinedunder light microscope. In the case of the holmium laser incision, the average tissue mass loss was 1.73 g, tissue volume loss 3.57 ml and the depth of thermocoagulation was 1.17 mm. When the monopolar cutting electrode was used average tissue mass loss was 0.807 g, tissue volume loss 2.48 ml and the depth of thermocoagulation was 0.19 mm. Where holmium laser was used, it was observed that the layer of tissue with thermocoagulation changes was deeper than in the case of the monopolar cutting electrode. Moreover, it was noticed that holmium laser caused bigger tissue mass and volume loss than the cutting electrode.

  5. [Nd-YAG laser photocoagulation of scrotal sebaceous cysts].

    Science.gov (United States)

    Franco de Castro, A; Truhán, D; Carretero González, P; Alcover García, J

    2002-02-01

    Scrotum's sebaceous cyst is an usual pathology, not life threatening, but susceptible of infection, producing abscess with their associated cosmetic and psychological disturbance. The classical management is the complete excision, under local anaesthesia, to prevent its recidive. Until today, the use of de Nd-YAG laser for the management of the scrotum's sebaceous cysts as not been reported. We report a case of a young man with several scrotum's sebaceous cysts, treated successfully with the use of a Nd-YAG laser.

  6. Use of radars to monitor stream discharge by noncontact methods

    Science.gov (United States)

    Costa, J.E.; Cheng, R.T.; Haeni, F.P.; Melcher, N.; Spicer, K.R.; Hayes, E.; Plant, W.; Hayes, K.; Teague, C.; Barrick, D.

    2006-01-01

    Conventional measurements of river flows are costly, time‐consuming, and frequently dangerous. This report evaluates the use of a continuous wave microwave radar, a monostatic UHF Doppler radar, a pulsed Doppler microwave radar, and a ground‐penetrating radar to measure river flows continuously over long periods and without touching the water with any instruments. The experiments duplicate the flow records from conventional stream gauging stations on the San Joaquin River in California and the Cowlitz River in Washington. The purpose of the experiments was to directly measure the parameters necessary to compute flow: surface velocity (converted to mean velocity) and cross‐sectional area, thereby avoiding the uncertainty, complexity, and cost of maintaining rating curves. River channel cross sections were measured by ground‐penetrating radar suspended above the river. River surface water velocity was obtained by Bragg scattering of microwave and UHF Doppler radars, and the surface velocity data were converted to mean velocity on the basis of detailed velocity profiles measured by current meters and hydroacoustic instruments. Experiments using these radars to acquire a continuous record of flow were conducted for 4 weeks on the San Joaquin River and for 16 weeks on the Cowlitz River. At the San Joaquin River the radar noncontact measurements produced discharges more than 20% higher than the other independent measurements in the early part of the experiment. After the first 3 days, the noncontact radar discharge measurements were within 5% of the rating values. On the Cowlitz River at Castle Rock, correlation coefficients between the USGS stream gauging station rating curve discharge and discharge computed from three different Doppler radar systems and GPR data over the 16 week experiment were 0.883, 0.969, and 0.992. Noncontact radar results were within a few percent of discharge values obtained by gauging station, current meter, and hydroacoustic methods

  7. Analysis of erythema after Er:YAG laser skin resurfacing.

    Science.gov (United States)

    Ko, Na Young; Ahn, Hyo-Hyun; Kim, Soo-Nam; Kye, Young-Chul

    2007-11-01

    Postoperative erythema can be expected to occur in every patient after laser resurfacing, and pigmentary disturbances may be related to the intensity and the duration of erythema. This study was undertaken to assess the clinical features of erythema, the factors that influence its duration, and the relation between the duration of erythema and the incidence of hyperpigmentation and hypopigmentation in skin of Asian persons after Er:YAG laser resurfacing. A total of 218 patients (skin phototypes III to V) were recruited and treated with a short-pulsed Er:YAG laser, a variable-pulsed Er:YAG laser, or a dual-mode Er:YAG laser for skin resurfacing. Clinical assessments were performed retrospectively using medical charts and serial photographs. Postoperative erythema was observed in all patients after Er:YAG laser resurfacing with a mean duration of 4.72 months. In 98.2% of patients, erythema faded completely within 12 months. Postinflammatory hyperpigmentation was observed in 38.1% of patients after Er:YAG laser resurfacing. Skin phototype, level of ablation, and depth of thermal damage caused by a long-pulsed laser appear to be important factors that affect the duration of erythema. Moreover, prolonged erythema was related to the risk of postinflammatory hyperpigmentation.

  8. Our first clinical experience with radiosynoviorthesis by means of (166)Ho-holmium-boro-macroaggregates.

    Science.gov (United States)

    Kraft, Otakar; Kasparek, R; Ullmann, V; Melichar, F; Kropacek, M; Mirzajevov, M

    2005-01-01

    In this paper, we evaluate the therapeutic and adverse effects of the application of 166-holmium-boro-macroaggregates (HMBA) in radiosynovectomy (RSO) of the knees. We assessed the efficacy and safety of (166)Ho-HBMA in a prospective clinical trial in patients suffering from chronic synovitis. An effective component of radiopharmaceutical (166)Ho-boro-macroaggregates is radionuclide (166)Ho which has both beta-emission and gamma-emission. The physical half-life time of 166 Ho is 26.8 hours. After application of the radiopharmaceutical into a joint cavity, the effect of beta-emission causes radiation necrosis of pathologically changed (inflamed) synovial membrane. From 15th April 2005, we have started RSO of knees by means of new radiopharmaceutical (166)Ho-boro-macroaggregates in patients with gonarthrosis, rheumatoid arthritis, chronic synovitis, psoriatic arthritis, gout arthropathy. Seventeen intra-articular injections were performed in fifteen patients receiving a mean activity of 972 MBq (range: 904-1,057 MBq) (166)Ho-HMBA. The patients were hospitalized for three days. Side effects were evaluated during hospital stay and after 6-8 weeks. Static scintigraphy of knee joints and measurements of blood radioactivity were performed. Therapeutic effects were evaluated after 6-8 weeks. In 2 hours and 2 days after application, we proved, by means of knee and inguinal scintigraphy, only insignificant radiopharmaceutical leakage from the joint cavity to the inguinal lymph nodes in four patients. In treated patients, no serious adverse effects occurred. Nine patients were without complaints; 4 patients had slight knee exsudation and 2 patients had great exsudation. Therapeutic effects after 6-8 weeks were as follows: 2 patients were without pain, 9 with lower pain, 3 with the same pain and 1 patient with increased pain. Joint motion was improved in 7 patients, remained the same in 7 patients and was impaired in 1 patient. Analgesics consumption was lower in 5 patients

  9. Clinical application of the Nd-YAG and Ho-YAG lasers in otolaryngology: head and neck surgery

    Science.gov (United States)

    Kukwa, Andrzej; Tulibacki, Marek P.; Dudziec, Katarzyna; Wojtowicz, Piotr

    1997-10-01

    The authors present their clinical experience regarding the possibilities of application of Nd:YAG and Ho:YAG lasers for the treatment of disorders in the area of the upper respiratory tract sinuses and ears. This technique makes it possible to perform a number of procedures in local anesthesia which considerably improves the economic effectiveness of the treatment. In case of the Nd:YAG laser they have also utilized the effect of deep coagulation of the soft tissues, whereas the Ho:YAG laser energy was applied for the surgery of bone tissue. The surgeries performed using laser beam enabled very good effect of treatment. They are competitive compared wit the methods used by traditional surgery.

  10. 3d noncontact humidity sensing technologies and methods of use thereof

    KAUST Repository

    Tai, Yanlong

    2017-09-08

    Noncontact sensing components are provided herein, in an aspect, they can be for an electronic device. The noncontact sensing components can contain a semiconductor layer having a r-GO portion and a CNT portion. The noncontact sensing components can be used to detect the presence or movement of a humidity source in the vicinity of the noncontact sensing component. The resistance/humidity response of the component can be based on the combined contribution of carbon nanotube (positive resistance variation) and reduced-graphene oxide (negative resistance variation) behaviors.

  11. Suppression of parasitic oscillations in a core-doped ceramic Nd:YAG laser by Sm:YAG cladding.

    Science.gov (United States)

    Huss, Rafael; Wilhelm, Ralf; Kolleck, Christian; Neumann, Jörg; Kracht, Dietmar

    2010-06-07

    The onset of parasitic oscillations limits the extraction efficiency and therefore energy scaling of Q-switched lasers. A solid-state laser was end pumped with a fiber-coupled diode laser and operated in q-cw as well as in passively Q-switched operation. For Q-switched operation, we demonstrate the suppression of parasitic oscillations in a core-doped ceramic Nd:YAG laser by Sm:YAG cladding.

  12. Efficacy of long pulse Nd:YAG laser versus fractional Er:YAG laser in the treatment of hand wrinkles.

    Science.gov (United States)

    Robati, Reza M; Asadi, Elmira; Shafiee, Anoosh; Namazi, Nastaran; Talebi, Atefeh

    2018-04-01

    There are different modalities for hand rejuvenation. Fractional Er:YAG laser and long pulse Nd:YAG laser were introduced for treating hand wrinkles. We plan to compare fractional Er:YAG laser and long pulse Nd:YAG laser in a randomized controlled double-blind design with multiple sessions and larger sample size in comparison with previous studies. Thirty-three participants with hand wrinkles entered this study. They were randomly allocated to undergo three monthly laser treatments on each hand, one with a fractional Er:YAG laser and the other with a long pulse Nd:YAG laser. The evaluations included assessment of clinical improvement determined by two independent dermatologists not enrolled in the treatment along with measuring skin biomechanical property of hands using a sensitive biometrologic device with the assessment of cutaneous resonance running time (CRRT). Moreover, potential side effects and patients' satisfaction have been documented at baseline, 1 month after each treatment, and 3 months after the final treatment session. Clinical evaluation revealed both modalities significantly reduce hand wrinkles (p value lasers. Mean CRRT values also decreased significantly after the laser treatment compared to those of the baseline in both laser groups. There was no serious persistent side effect after both laser treatments. Both fractional Er:YAG and long pulse Nd:YAG lasers show substantial clinical improvement of hand skin wrinkles with no serious side effects. However, combination treatment by these lasers along with the other modalities such as fat transfer could lead to better outcomes in hand rejuvenation. IRCT2016032020468N4.

  13. Bone dissemination of prostate cancer after holmium laser enucleation of the prostate: a case report and a review of the literature.

    Science.gov (United States)

    Koguchi, Dai; Nishi, Morihiro; Satoh, Takefumi; Shitara, Toshiya; Matsumoto, Kazumasa; Fujita, Tetsuo; Yoshida, Kazunari; Iwamura, Masatsugu

    2014-02-01

    We report a case of dissemination of prostate cancer after holmium laser enucleation of the prostate in an 80-year-old patient. The patient presented at hospital because of nocturia. Transrectal ultrasound-guided biopsy was carried out because of high serum prostate-specific antigen (3.55 ng/mL), but it showed no malignancies. Benign prostate hyperplasia was diagnosed, and he was started on an α1-blocker. Although the urinary symptom improved with silodosin, acute urinary retention occurred 3 years after therapy began. Holmium laser enucleation of the prostate for relief of bladder outlet obstruction enabled discharge of urine. Pathological examination of the resected tissue found adenocarcinoma with a high Gleason score, 4 + 5. Serum alkaline phosphatase increased rapidly after holmium laser enucleation, and bone scintigraphy confirmed multiple bone metastases. Prostate cancer, T1bN0M1b, was diagnosed. © 2013 The Japanese Urological Association.

  14. Teaching learning algorithm based optimization of kerf deviations in pulsed Nd:YAG laser cutting of Kevlar-29 composite laminates

    Science.gov (United States)

    Gautam, Girish Dutt; Pandey, Arun Kumar

    2018-03-01

    Kevlar is the most popular aramid fiber and most commonly used in different technologically advanced industries for various applications. But the precise cutting of Kevlar composite laminates is a difficult task. The conventional cutting methods face various defects such as delamination, burr formation, fiber pullout with poor surface quality and their mechanical performance is greatly affected by these defects. The laser beam machining may be an alternative of the conventional cutting processes due to its non-contact nature, requirement of low specific energy with higher production rate. But this process also faces some problems that may be minimized by operating the machine at optimum parameters levels. This research paper examines the effective utilization of the Nd:YAG laser cutting system on difficult-to-cut Kevlar-29 composite laminates. The objective of the proposed work is to find the optimum process parameters settings for getting the minimum kerf deviations at both sides. The experiments have been conducted on Kevlar-29 composite laminates having thickness 1.25 mm by using Box-Benkhen design with two center points. The experimental data have been used for the optimization by using the proposed methodology. For the optimization, Teaching learning Algorithm based approach has been employed to obtain the minimum kerf deviation at bottom and top sides. A self coded Matlab program has been developed by using the proposed methodology and this program has been used for the optimization. Finally, the confirmation tests have been performed to compare the experimental and optimum results obtained by the proposed methodology. The comparison results show that the machining performance in the laser beam cutting process has been remarkably improved through proposed approach. Finally, the influence of different laser cutting parameters such as lamp current, pulse frequency, pulse width, compressed air pressure and cutting speed on top kerf deviation and bottom kerf

  15. Thermodynamic properties of the neutral and ionic components of the holmium trichloride vapor

    International Nuclear Information System (INIS)

    Kuznetsov, A.Yu.; Kudin, L.S.; Pogrebnoj, A.M.; Butman, M.F.; Burdukovskaya, G.G.

    1999-01-01

    The composition of saturated vapor above holmium trichloride in the temperature range of 887 - 1051 K is studied by the method of high-temperature mass spectrometry. Neutral components are presented by molecules of Ho n Cl 3n , n = 1 - 4 charged ones - by Cl - , HoCl 4 - , Ho 2 Cl 7 - ions. Sublimation enthalpies and formation enthalpies of gaseous molecules and ions (298 K): Δ s H Deg (HoCl 3 ) = 284 ±6, Δ s H Deg (Ho 2 Cl 6 ) = 352 ± 20; ΔH Deg (HoCl 3 ) = -722 ± 6; Δ f H Deg (Ho 2 Cl 6 ) = -1661 ± 20; Δ f H Deg (HoCl 4 - ) ≤ - 1191 ± 20, Δ f H Deg (Ho-2Cl 7 - ) ≤ -2127 ± 30 kJ/mol are determined. The value of electron affinity for HoCl 4 radical (A 0 ≥ 3.6 eV) is estimated [ru

  16. Microspheres of polyester loaded with Holmium-165: effect of gamma irradiation on the polymeric structure

    International Nuclear Information System (INIS)

    Azevedo, Mariangela de Burgos M. de; Pires, Geovanna; Lira, Rafael A. de; Geraldes, Adriana N.; Nascimento, Nanci; Melo, Vitor Hugo Soares de; Kodama, Yasko

    2011-01-01

    Biodegradable polymers containing radioactive isotopes have potential applications as delivery vehicles of beta radiation to the cancer tumors by brachytherapy. 166-Ho is an example of such radioisotope emitting high-energy beta particles, and also its gamma rays allow nuclear imaging in everywhere is applied. Among the biodegradable polymers, different types of poly(lactide) have been investigated in our laboratory, and poly(L-lactide) (PLLA) was used as substrate to prepare microparticles loaded with holmium acetylacetonate HoAcAc (PLLA-HoAcAc-MP). The aim of this study was to evaluate the stability of these microparticles to gamma radiation. The PLLA-HoAcAc-MP were irradiated in a nuclear reactor IEA-R1 at IPEN/CNEN-SP, and their stability studied out with gamma radiation of 25, 50 and 100 kGy doses. MP were characterized before and after irradiation by differential scanning calorimetry analysis (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD) and con focal laser scanning microscopy (CLSM). Preliminary results showed that gamma radiation did not damage morphologically the prepared PLLA-HoAcAc-MP in the dose range studied, and this procedure may be an important tool for knowing the stabilities of the polymers studied as MP for possible application in brachytherapy. (author)

  17. Development and evaluation of holmium doped phosphate glass microspheres for selective internal radiotherapy

    International Nuclear Information System (INIS)

    Barros Filho, Eraldo C.; Martinelli, Jose Roberto; Squair, Peterson L; Osso Junior, Joao A.; Sene, Frank Ferrer

    2013-01-01

    Selective Internal Radiotherapy is used to treat hepatocellular carcinoma. In this treatment 90 Y -doped aluminosilicate glass microspheres are introduced in the hepatic artery and they migrate to the liver near to the tumor where they are trapped in the arterioles. The radiation β- emitted by the decay of 90 Y annihilates the cancer cells. A macroaggregate of albumin containing technetium is previously used to monitor the lung shunt and to prevent the spreading of 90 Y during the treatment. In the present work, 165 Ho- doped phosphate glass microspheres were developed aiming that application. 165 Ho has high cross section for neutron capture (64 bars) and 166 Ho decays emitting β- radiation with appropriate energy for killing cancer cells, and gamma rays with low energy which can be used to obtain images of the microspheres location and to check possible occurrence of lung shunt. Holmium also is highly paramagnetic and can be used to obtain images whereby NMR. The glass matrix consists of (P 2 O 5 ) tetrahedrons and can be produced by a relatively lower melting temperature of chemical compounds. The 31 P decays by emitting β- radiation and contributes to the absorbed dose, helping to annihilate the cancer cells. The microspheres were produced by using two methods: the flame and the gravitation falling methods to obtain microspheres with appropriate properties. (author)

  18. Hybrid Pulsed Nd:YAG Laser

    Science.gov (United States)

    Miller, Sawyer; Trujillo, Skyler; Fort Lewis College Laser Group Team

    This work concerns the novel design of an inexpensive pulsed Nd:YAG laser, consisting of a hybrid Kerr Mode Lock (KLM) and Q-switch pulse. The two pulse generation systems work independently, non simultaneously of each other, thus generating the ability for the user to easily switch between ultra-short pulse widths or large energy density pulses. Traditionally, SF57 glass has been used as the Kerr medium. In this work, novel Kerr mode-locking mediums are being investigated including: tellurite compound glass (TeO2), carbon disulfide (CS2), and chalcogenide glass. These materials have a nonlinear index of refraction orders of magnitude,(n2), larger than SF57 glass. The Q-switched pulse will utilize a Pockels cell. As the two pulse generation systems cannot be operated simultaneously, the Pockels cell and Kerr medium are attached to kinematic mounts, allowing for quick interchange between systems. Pulse widths and repetition rates will vary between the two systems. A goal of 100 picosecond pulse widths are desired for the mode-locked system. A goal of 10 nanosecond pulse widths are desired for the Q-switch system, with a desired repetition rate of 50 Hz. As designed, the laser will be useful in imaging applications.

  19. Compact corner-pumped Nd:YAG/YAG composite slab 1319 nm/1338 nm laser

    International Nuclear Information System (INIS)

    Liu, H; Gong, M; Wushouer, X; Gao, S

    2010-01-01

    A corner-pumped type is a new pumping type in the diode-pumped solid-state lasers, which has the advantages of high pump efficiency and favorable pump uniformity. A corner-pumped Nd:YAG/YAG composite slab continuous-wave 1319 nm/1338 nm dual-wavelength laser is first demonstrated in this paper. When the cavity length is 25 mm, the maximal output power is up to 7.62 W with a slope efficiency of 16.6% and an optical-to-optical conversion efficiency of 17%. The corresponding spectral line widths of 1319 nm laser and 1338 nm laser are 0.11 and 0.1 nm, respectively. The short-term instability of the output power is better than 1% when the pumping power is 39.5 W. The experimental results show that a corner-pumped type is a kind of feasible schedules in the design of diode-pumped solid-state 1.3 μm lasers with low or medium output powers

  20. Noncontact inspection laser system for characterization of piezoelectric samples

    International Nuclear Information System (INIS)

    Jimenez, F.J.; Frutos, J. de

    2004-01-01

    In this work measurements on a piezoelectric sample in dynamic behavior were taken, in particular, around the frequencies of resonance for the sample where the nonlineal effects are accentuated. Dimension changes in the sample need to be studied as that will allow a more reliable characterization of the piezoelectric samples. The goal of this research is to develop an inspection system able to obtain measurements, using a noncontact laser displacement transducer, also able to visualize, in three-dimensional graphic environment, the displacement that takes place in a piezoelectric sample surface. In resonant mode, the vibration mode of the sample is visualized

  1. Microwave non-contact imaging of subcutaneous human body tissues.

    Science.gov (United States)

    Kletsov, Andrey; Chernokalov, Alexander; Khripkov, Alexander; Cho, Jaegeol; Druchinin, Sergey

    2015-10-01

    A small-size microwave sensor is developed for non-contact imaging of a human body structure in 2D, enabling fitness and health monitoring using mobile devices. A method for human body tissue structure imaging is developed and experimentally validated. Subcutaneous fat tissue reconstruction depth of up to 70 mm and maximum fat thickness measurement error below 2 mm are demonstrated by measurements with a human body phantom and human subjects. Electrically small antennas are developed for integration of the microwave sensor into a mobile device. Usability of the developed microwave sensor for fitness applications, healthcare, and body weight management is demonstrated.

  2. Algorithm describing pressure distribution of non-contact TNT explosion

    Directory of Open Access Journals (Sweden)

    Radosław Kiciński

    2014-12-01

    Full Text Available [b]Abstract[/b]. The aim of this study is to develop a computational algorithm, describing the shock wave pressure distribution in the space induced by non-contact TNT explosion. The procedure describes pressure distribution on a damp surface of the hull. Simulations have been carried out using Abaqus/CAE. The study also shows the pressure waveform descriptions provided by various authors and presents them in charts. The formulated conclusions convince efficiency of the algorithm application.[b]Keywords:[/b] Underwater explosion, shock wave, CAE, TNT, Kobben class submarine

  3. Clinical effects of transcatheter hepatic arterial embolization with holmium-166 poly(l-lactic acid) microspheres in healthy pigs

    Energy Technology Data Exchange (ETDEWEB)

    Vente, M.A.D.; Nijsen, J.F.W.; Wit, T.C. de; Schip, A.D. van het [University Medical Center Utrecht, Department of Nuclear Medicine, P.O. Box 85500, Utrecht (Netherlands); Seppenwoolde, J.H.; Seevinck, P.R. [University Medical Center Utrecht, Image Sciences Institute, Utrecht (Netherlands); Krijger, G.C. [Delft University of Technology, Department of Radiation, Radionuclides and Reactors, Faculty of Applied Sciences, Delft (Netherlands); Huisman, A. [University Medical Center Utrecht, Department of Clinical Chemistry and Haematology, Utrecht (Netherlands); Zonnenberg, B.A. [University Medical Center Utrecht, Department of Internal Medicine, Utrecht (Netherlands); Ingh, T.S.G.A.M. van den [TCCI Consultancy B.V., P.O. Box 85032, Utrecht (Netherlands)

    2008-07-15

    The aim of this study is to evaluate the toxicity of holmium-166 poly(l-lactic acid) microspheres administered into the hepatic artery in pigs. Healthy pigs (20-30 kg) were injected into the hepatic artery with holmium-165-loaded microspheres ({sup 165}HoMS; n = 5) or with holmium-166-loaded microspheres ({sup 166}HoMS; n = 13). The microspheres' biodistribution was assessed by single-photon emission computed tomography and/or MRI. The animals were monitored clinically, biochemically, and ({sup 166}HoMS group only) hematologically over a period of 1 month ({sup 165}HoMS group) or over 1 or 2 months ({sup 166}HoMS group). Finally, a pathological examination was undertaken. After microsphere administration, some animals exhibited a slightly diminished level of consciousness and a dip in appetite, both of which were transient. Four lethal adverse events occurred in the {sup 166}HoMS group due either to incorrect administration or comorbidity: inadvertent delivery of microspheres into the gastric wall (n = 2), preexisting gastric ulceration (n = 1), and endocarditis (n = 1). AST levels were transitorily elevated post-{sup 166}HoMS administration. In the other blood parameters, no abnormalities were observed. Nuclear scans were acquired from all animals from the {sup 166}HoMS group, and MRI scans were performed if available. In pigs from the {sup 166}HoMS group, atrophy of one or more liver lobes was frequently observed. The actual radioactivity distribution was assessed through ex vivo {sup 166m}Ho measurements. It can be concluded that the toxicity profile of HoMS is low. In pigs, hepatic arterial embolization with {sup 166}HoMS in amounts corresponding with liver-absorbed doses of over 100 Gy, if correctly administered, is not associated with clinically relevant side effects. This result offers a good perspective for upcoming patient trials. (orig.)

  4. Sequence of oral bacterial co-adhesion and non-contact brushing

    NARCIS (Netherlands)

    van der Mei, H. C.; Rustema-Abbing, M.; Bruinsma, G. M.; Gottenbos, B.; Busscher, H. J.

    Non-contact plaque removal offers advantages in interproximal spaces, fissures, and pockets. It requires the generation of strong fluid flows and the inclusion of air bubbles to become effective. A pair of co-adhering streptococci and actinomyces has been used previously to demonstrate non-contact

  5. Highly efficient solar-pumped Nd:YAG laser.

    Science.gov (United States)

    Liang, Dawei; Almeida, Joana

    2011-12-19

    The recent progress in solar-pumped laser with Fresnel lens and Cr:Nd:YAG ceramic medium has revitalized solar laser researches, revealing a promising future for renewable reduction of magnesium from magnesium oxide. Here we show a big advance in solar laser collection efficiency by utilizing an economical Fresnel lens and a most widely used Nd:YAG single-crystal rod. The incoming solar radiation from the sun is focused by a 0.9 m diameter Fresnel lens. A dielectric totally internally reflecting secondary concentrator is employed to couple the concentrated solar radiation from the focal zone to a 4 mm diameter Nd:YAG rod within a conical pumping cavity. 12.3 W cw laser power is produced, corresponding to 19.3 W/m(2) collection efficiency, which is 2.9 times larger than the previous results with Nd:YAG single-crystal medium. Record-high slope efficiency of 3.9% is also registered. Laser beam quality is considerably improved by pumping a 3 mm diameter Nd:YAG rod.

  6. DEBONDING OF CERAMIC BRACKETS BY ER:YAG LASER

    Directory of Open Access Journals (Sweden)

    Fidan ALAKUŞ-SABUNCUOĞLU

    2016-04-01

    Full Text Available Purpose: The objective of the present study is to evaluate the effects of Er:YAG laser debonding of ceramic brackets on the bond strength and the amount of adhesive resin remnant. Materials and Methods: Twenty human mandibular incisors were randomly divided into two groups of 10 and polycrystalline ceramic brackets (Transcend series 6000, 3M Unitek, Monrovia, CA, USA were bonded on enamel surfaces. Group 1 was the control group in which no laser application was performed prior to the shear bond strength (SBS testing. In Group 2, Er:YAG was applied in 3W power for 6 seconds using the scanning method. The brackets were tested for SBS with an Instron universal testing machine and results were expressed in megapascals (MPa. The amount of adhesive remnant was evaluated with Adhesive Remnant Index (ARI. One-way analysis of variance and Tukey’s post-hoc tests were used for statistical analysis. Results: Mean ± standard deviation of SBS values in the control group was 13.42 ±1.23 MPa and 8.47 ±0.71 MPa in the Er:YAG group and this difference was statistically significant (p<0.05. The evaluation of ARI scores demonstrated more adhesive was left on the enamel surface with Er:YAG group. Conclusion: 3W power Er:YAG laser application with the scanning method to polycrystalline ceramic brackets demonstrated lower bond strengths and higher ARI scores during the debonding procedure.

  7. Experimental application of pulsed Ho:YAG laser-induced liquid jet as a novel rigid neuroendoscopic dissection device.

    Science.gov (United States)

    Ohki, Tomohiro; Nakagawa, Atsuhiro; Hirano, Takayuki; Hashimoto, Tokitada; Menezes, Viren; Jokura, Hidefumi; Uenohara, Hiroshi; Sato, Yasuhiko; Saito, Tsutomu; Shirane, Reizo; Tominaga, Teiji; Takayama, Kazuyoshi

    2004-01-01

    Although water jet technology has been considered as a feasible neuroendoscopic dissection methodology because of its ability to perform selective tissue dissection without thermal damage, problems associated with continuous use of water and the ensuing fountain-effect-with catapulting of the tissue-could make water jets unsuitable for endoscopic use, in terms of safety and ease of handling. Therefore, the authors experimented with minimization of water usage during the application of a pulsed holmium:yttrium-aluminum-garnet (Ho:YAG) laser-induced liquid jet (LILJ), while assuring the dissection quality and the controllability of a conventional water jet dissection device. We have developed the LILJ generator for use as a rigid neuroendoscope, discerned its mechanical behavior, and evaluated its dissection ability using the cadaveric rabbit ventricular wall. The LILJ generator is incorporated into the tip of a stainless steel tube (length: 22 cm; internal diameter: 1.0 mm; external diameter: 1.4 mm), so that the device can be inserted into a commercial, rigid neuroendoscope. Briefly, the LILJ is generated by irradiating an internally supplied water column within the stainless steel tube using the pulsed Ho:YAG laser (wave length: 2.1 microm, pulse duration time: 350 microseconds) and is then ejected through the metal nozzle (internal diameter: 100 microm). The Ho:YAG laser pulse energy is conveyed through optical quartz fiber (core diameter: 400 microm), while cold water (5 degrees C) is internally supplied at a rate of 40 ml/hour. The relationship between laser energy (range: 40-433 mJ/pulse), standoff distance (defined as the distance between the tip of the optical fiber and the nozzle end; range: 10-30 mm), and the velocity, shape, pressure, and average volume of the ejected jet were analyzed by means of high-speed camera, PVDF needle hydrophone, and digital scale. The quality of the dissection plane, the preservation of blood vessels, and the penetration depth

  8. Pressure potential and stability analysis in an acoustical noncontact transportation

    Science.gov (United States)

    Li, J.; Liu, C. J.; Zhang, W. J.

    2017-01-01

    Near field acoustic traveling wave is one of the most popular principles in noncontact manipulations and transportations. The stability behavior is a key factor in the industrial applications of acoustical noncontact transportation. We present here an in-depth analysis of the transportation stability of a planar object levitated in near field acoustic traveling waves. To more accurately describe the pressure distributions on the radiation surface, a 3D nonlinear traveling wave model is presented. A closed form solution is derived based on the pressure potential to quantitatively calculate the restoring forces and moments under small disturbances. The physical explanations of the effects of fluid inertia and the effects of non-uniform pressure distributions are provided in detail. It is found that a vibration rail with tapered cross section provides more stable transportation than a rail with rectangular cross section. The present study sheds light on the issue of quantitative evaluation of stability in acoustic traveling waves and proposes three main factors that influence the stability: (a) vibration shape, (b) pressure distribution and (c) restoring force/moment. It helps to provide a better understanding of the physics behind the near field acoustic transportation and provide useful design and optimization tools for industrial applications.

  9. Cardiorespiratory interactions: Noncontact assessment using laser Doppler vibrometry.

    Science.gov (United States)

    Sirevaag, Erik J; Casaccia, Sara; Richter, Edward A; O'Sullivan, Joseph A; Scalise, Lorenzo; Rohrbaugh, John W

    2016-06-01

    The application of a noncontact physiological recording technique, based on the method of laser Doppler vibrometry (LDV), is described. The effectiveness of the LDV method as a physiological recording modality lies in the ability to detect very small movements of the skin, associated with internal mechanophysiological activities. The method is validated for a range of cardiovascular variables, extracted from the contour of the carotid pulse waveform as a function of phase of the respiration cycle. Data were obtained from 32 young healthy participants, while resting and breathing spontaneously. Individual beats were assigned to four segments, corresponding with inspiration and expiration peaks and transitional periods. Measures relating to cardiac and vascular dynamics are shown to agree with the pattern of effects seen in the substantial body of literature based on human and animal experiments, and with selected signals recorded simultaneously with conventional sensors. These effects include changes in heart rate, systolic time intervals, and stroke volume. There was also some evidence for vascular adjustments over the respiration cycle. The effectiveness of custom algorithmic approaches for extracting the key signal features was confirmed. The advantages of the LDV method are discussed in terms of the metrological properties and utility in psychophysiological research. Although used here within a suite of conventional sensors and electrodes, the LDV method can be used on a stand-alone, noncontact basis, with no requirement for skin preparation, and can be used in harsh environments including the MR scanner. © 2016 Society for Psychophysiological Research.

  10. Non-Contact Laser Based Ultrasound Evaluation of Canned Foods

    Science.gov (United States)

    Shelton, David

    2005-03-01

    Laser-Based Ultrasound detection was used to measure the velocity of compression waves transmitted through canned foods. Condensed broth, canned pasta, and non-condensed soup were evaluated in these experiments. Homodyne adaptive optics resulted in measurements that were more accurate than the traditional heterodyne method, as well as yielding a 10 dB gain in signal to noise. A-Scans measured the velocity of ultrasound sent through the center of the can and were able to distinguish the quantity of food stuff in its path, as well as distinguish between meat and potato. B-Scans investigated the heterogeneity of the sample’s contents. The evaluation of canned foods was completely non-contact and would be suitable for continuous monitoring in production. These results were verified by conducting the same experiments with a contact piezo transducer. Although the contact method yields a higher signal to noise ratio than the non-contact method, Laser-Based Ultrasound was able to detect surface waves the contact transducer could not.

  11. Non-Contact Conductivity Measurement for Automated Sample Processing Systems

    Science.gov (United States)

    Beegle, Luther W.; Kirby, James P.

    2012-01-01

    A new method has been developed for monitoring and control of automated sample processing and preparation especially focusing on desalting of samples before analytical analysis (described in more detail in Automated Desalting Apparatus, (NPO-45428), NASA Tech Briefs, Vol. 34, No. 8 (August 2010), page 44). The use of non-contact conductivity probes, one at the inlet and one at the outlet of the solid phase sample preparation media, allows monitoring of the process, and acts as a trigger for the start of the next step in the sequence (see figure). At each step of the muti-step process, the system is flushed with low-conductivity water, which sets the system back to an overall low-conductivity state. This measurement then triggers the next stage of sample processing protocols, and greatly minimizes use of consumables. In the case of amino acid sample preparation for desalting, the conductivity measurement will define three key conditions for the sample preparation process. First, when the system is neutralized (low conductivity, by washing with excess de-ionized water); second, when the system is acidified, by washing with a strong acid (high conductivity); and third, when the system is at a basic condition of high pH (high conductivity). Taken together, this non-contact conductivity measurement for monitoring sample preparation will not only facilitate automation of the sample preparation and processing, but will also act as a way to optimize the operational time and use of consumables

  12. On repeated corneal applanation with the Goldmann and two non-contact tonometers.

    Science.gov (United States)

    Almubrad, Turki M; Ogbuehi, Kelechi C

    2010-03-01

    Several authors believe it is necessary to randomise the order in which contact and non-contact tonometers are used in comparison studies. This study was carried out to investigate the effect of repeated applanation on the measured intraocular pressure. One set of measurements per session was made on each of three sessions (one session per day) with the Goldmann and two non-contact tonometers (Topcon CT80 and Keeler Pulsair EasyEye), in a pre-determined order, on one randomly selected eye of 120 subjects randomised to one of two groups. For session one, only the non-contact tonometers were used to assess the intraocular pressure of both groups. For session two, either non-contact or Goldmann tonometry was performed first and this order was reversed for session 3. Average intraocular pressures were compared between sessions to determine the presence or absence of effects on the intraocular pressure caused by prior repeated applanation with the Goldmann or either one (or both) of the non-contact tonometers. Prior applanation with a non-contact tonometer did not cause a significant (p > 0.05) reduction of the mean pressure measured with either non-contact tonometer. The mean pressure was slightly but significantly (p contact tonometers in both subject groups) when non-contact tonometry was performed after Goldmann tonometry. There was no significant difference (p > 0.05) between the pressures measured with the Goldmann tonometer prior to and subsequent to non-contact tonometry, in both subject groups. A small but statistically significant reduction in the intraocular pressure was found following applanation with the Goldmann tonometer but not with either one of two non-contact tonometers.

  13. Evaluation in vitro of effects of Er:YAG and Nd:YAG lasers irradiation on root canal wall, by stereoscopy, scanning electron micrography and thermographic camera

    International Nuclear Information System (INIS)

    Goya, Claudia

    2001-01-01

    This study was carried out to evaluate in vitro the effects of Nd:YAG laser and Er:YAG laser irradiation in the root canal wall by SEM, evaluating the apical leakage and the temperature changes during the laser irradiation. Seventy four extracted human teeth were used, they were instrumented and divided into seven groups of 10 teeth each. The teeth were evaluated through stereoscopy, by SEM, and with the thermographic camera. The Nd:YAG laser irradiation parameters were 100 mJ/p, 15 Hz, and Er:YAG laser were 160 mJ/p and 10 Hz, the irradiation was 4 times at 2 mm/sec speed, with 20 sec interval. The apical leakage was not observed in the teeth irradiated by Nd:YAG laser alone or in association with Er:YAG laser. However in the teeth irradiated only by the Er:YAG laser we observed a little leakage. By SEM observation the Nd:YAG laser irradiation showed melting and recrystallization in the dentin surface closing dentinal tubules, and in the samples irradiated by Er:Y AG laser a clean surface, opened dentinal tubules, and the combination by two lasers, showed melting covering some dentinal tubules The thermographic study found the temperature increase was not more than 6 deg C. This study showed the safety parameters applications of Er:YAG laser in association with Nd:YAG laser in root canal treatment, in order to not cause thermal damages to the periodontal tissues. (author)

  14. Nd:YAG Laser Firmware Design under RTOS Operation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B. G.; Kim, W. Y.; Park, G. R.; Moon, D. S.; Hong, J. H.; Kim, H. J.; Cho, J. S. [Pusan National University (Korea)

    2000-07-01

    A pulsed Nd:YAG laser is used widely for materials processing and medical instrument. It's very important to control the laser energy density in those fields using a pulsed Nd:YAG laser. A pulse repetition rate and a pulse width are regarded as the most dominant factors to control the energy density of laser beam. In this paper, the alternating charge and discharge system was designed to adjust a pulse repetition rate. This system is controlled by microprocessor and allows to replace an expensive condenser for high frequency to cheap one of low frequency. In addition, The microcontroller monitors the flow of cooling water, short circuit, and miss firing and so on. We designed Nd:YAG laser firmware with smart microcontroller, and want to explain general matters about the firmware from now. (author). 8 refs., 6 figs.

  15. Yb:YAG Lasers for Space Based Remote Sensing

    Science.gov (United States)

    Ewing, J.J.; Fan, T. Y.

    1998-01-01

    Diode pumped solid state lasers will play a prominent role in future remote sensing missions because of their intrinsic high efficiency and low mass. Applications including altimetry, cloud and aerosol measurement, wind velocity measurement by both coherent and incoherent methods, and species measurements, with appropriate frequency converters, all will benefit from a diode pumped primary laser. To date the "gold standard" diode pumped Nd laser has been the laser of choice for most of these concepts. This paper discusses an alternate 1 micron laser, the YB:YAG laser, and its potential relevance for lidar applications. Conceptual design analysis and, to the extent possible at the time of the conference, preliminary experimental data on the performance of a bread board YB:YAG oscillator will be presented. The paper centers on application of YB:YAG for altimetry, but extension to other applications will be discussed.

  16. Growth of single-crystal YAG fiber optics.

    Science.gov (United States)

    Nie, Craig D; Bera, Subhabrata; Harrington, James A

    2016-07-11

    Single-crystal YAG (Y3Al5O12) fibers have been grown by the laser heated pedestal growth technique with losses as low as 0.3 dB/m at 1.06 μm. These YAG fibers are as long as about 60 cm with diameters around 330 μm. The early fibers were grown from unoriented YAG seed fibers and these fibers exhibited facet steps or ridges on the surface of the fiber. However, recently we have grown fibers using an oriented seed to grow step-free fibers. Scattering losses made on the fibers indicate that the scattering losses are equal to about 30% of the total loss.

  17. Our first clinical experience with radiosynoviorthesis by means of 166Ho-holmium-boro-macroaggregates

    International Nuclear Information System (INIS)

    Kraft, O.; Ullmann, V.; Kasparek, R.; Melichar, F.; Kropacek, M.; Mirzajevova, M.

    2005-01-01

    In this paper, we evaluate the therapeutic and adverse effects of the application of 166- holmium-boro-macroaggregates (HMBA) in radiosynovectomy (RSO) of the knees. We assessed the efficacy and safety of 166H o-HBMA in a prospective clinical trial in patients suffering from chronic synovitis. An effective component of radiopharmaceutical 166H o-boro-macroaggregates is radionuclide 166H o which has both b-emission and g-emission. The physical half-life time of 166H o is 26.8 hours. After application of the radiopharmaceutical into a joint cavity, the effect of b-emission causes radiation necrosis of pathologically changed (inflamed) synovial membrane. From 15 april 2005, we have started RSO of knees by means of new radiopharmaceutical 166H o-boro-macroaggregates in patients with gonarthrosis, rheumatoid arthritis, chronic synovitis, psoriatic arthritis, gout arthropathy. Seventeen intra-articular injections were performed in fifteen patients receiving a mean activity of 972 MBq (range: 904.1057 MBq) 166H o-HMBA. The patients were hospitalized for three days. Side effects were evaluated during hospital stay and after 6.8 weeks. Static scintigraphy of knee joints and measurements of blood radioactivity were performed. Therapeutic effects were evaluated after 6.8 weeks. In 2 hours and 2 days after application, we proved, by means of knee and inguinal scintigraphy, only insignificant radiopharmaceutical leakage from the joint cavity to the inguinal lymph nodes in four patients. In treated patients, no serious adverse effects occurred. Nine patients were without complaints; 4 patients had slight knee exudation and 2 patients had great exudation. Therapeutic effects after 6.8 weeks were as follows: 2 patients were without pain, 9 with lower pain, 3 with the same pain and 1 patient with increased pain. Joint motion was improved in 7 patients, remained the same in 7 patients and was impaired in 1 patient. Analgesics consumption was lower in 5 patients, the same in 9

  18. Specific heat of holmium and YNi{sub 2}B{sub 2}C. Criticalbehaviour and superconducting properties; Spezifische Waerme von Holmium und YNi{sub 2}B{sub 2}C. Kritisches Verhalten und supraleitende Eigenschaften

    Energy Technology Data Exchange (ETDEWEB)

    Bekkali, Abdelhakim

    2010-01-04

    Object of the thesis is the study of the specific heat of holmium and YNi{sub 2}B{sub 2}C in the temperature ranges from 50 to 200 KI respectively from 380 mK to 20 K in magnetic fields up to 9 T. In the present thesis the criticalbehaviour of YNi{sub 2}B{sub 2}C and properties of the superconducting state of tne non-magnetic rare-earth nickel borocarbide YNi{sub 2}B{sub 2}C are studied by means of a self-developed measurement apparatur of the specific heat using the quasi-adiabatic heating-pulse method as well as of holmium by means of the relaxation method. In this thesis reliable statements about the critical exponents on monocrystalline holmium could be made. The study on holmium proves that the critical behaviour of the specific heats cannot be described in the framework of the predictions of the chiral universality classes. By means of measurements of the specific heat in this thesis could be confirmed that YNi{sub 2}B{sub 2}C is a multiband superconductor. The positive curvature of the boundary line below T{sub c} in the phase diagram yields a first hint to the many-band character of YNI{sub 2}B{sub 2}C. In the zero-field the electronic specific heat in the superconducting state c{sub es}(T) can be not explained in the framework of the pure BCS theory. At low temperatures a residual contribution by normally conducting electrons could be detected, which hints to a not completely opened energy gap. A possible explanation would be that a band (or several bands) with low charge-carrier concentration not contribute to the superconductivity. This result agrees with de Haas-van Alphen measurements on isostructural superconducting LuNi{sub 2}B{sub 2}C monocrystals, which suggest the many-band character of the superconductivity as well as a vanishing energy gap in one band. The fluctuation behaviour of the specific heat of YNi{sub 2}B{sub 2}C in the neighbourhood of the superconducting-normally conducting transition agrees well with that of the 3D-XY model. [German

  19. Surface alloy formation by adsorption of holmium on Ag/Mo(112) bimetallic surfaces

    Science.gov (United States)

    Kołaczkiewicz, Jan; Oleksy, Czesław

    2018-03-01

    Work function change measurements, low energy electron diffraction (LEED) and density functional theory (DFT) are used to determine the structures formed on Ag/Mo(112) bimetallic surfaces upon deposition of 0.5 monolayer (ML) of holmium. As the bimetallic surfaces, we have chosen the Mo(112) substrate covered with 1 or 2 ML of Ag. Such surfaces have the same symmetry as the Mo(112) face but different electronic properties. LEED experiment indicates that the c(2 × 2) structure is formed on (1 ML Ag)/Mo(112) bimetallic surface upon deposition of 0.5 ML of Ho. DFT calculations show that a type of Ag-Ho surface alloy is formed, with Ho atoms 0.6 Å below the distorted layer of Ag. This is neither a substitutional nor a subsurface alloy. It is found that the adsorption structure formed on the (2 ML Ag)/Mo(112) bimetallic surface depends on the annealing temperature. After deposition of 0.5 ML of Ho at 300 K, the LEED pattern of p(2 × 2) symmetry is observed. Annealing of the overlayer at 640 K irreversibly changes the p(2 × 2) pattern into a pattern of c(2 × 2) type. The results of DFT computations show that the c(2 × 2) structure of the Ag-Ho surface alloy is energetically most favorable. In this structure, 0.5 ML of Ho is between the two monolayers of Ag, and the symmetry of the topmost layer is changed. The work function change calculated for the c(2 × 2) structure is in a good agreement with the measured value (0.22 eV). The results show that adsorption of Ho on the Ag/Mo(112) bimetallic surfaces is substantially different than on the clean Mo(112).

  20. Studies on therapeutic method of liver cancer(hapatocellular carcinome)by Holmium-166 radionuclide

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Tae; Yoo, H. S.; Kim, M. J.; Han, K. H.; Park, C. I. [Yonsei University Medical College, Seoul (Korea, Republic of)

    1997-07-01

    As the study of radioactive nuclide, Holmium-166 in the treatment of liver cancer(hepatocellular carcinoma), this study was performed under the base of animal experimental. Using dog liver, percutaneous injection of Ho-166 MAA or chitosan with premade dose was done under the ultrasound guidance. Continuously the same procedure as previous one was performed in the skin hapatoma, which was developed by the injection of hepatocellular carcinoma cell in the nude mouse, In case of injected normal liver of dog, imaging study including ultrasound, CT and MRI was done in order to evaluate effect of Ho-166 and pathologic reaction. The result showed well defined nectosis of normal liver as well as skin hepatoma. The area of nectosis is dependent on the dose of injected Ho-166. Generally, pathologic reaction is tissue coagulation nectosis, Ho-166 particles, fibrosis and hemorrhage. In the clinical study, 50 patients with hapatoma was selected for this study under the agreement of patient. Under ultrasound guidance percutaneous injection of Ho-166 Maa or chitosan to tumor was performed and follow-up study was extended from 6 to 12 month. The result showed that 64% of patient were completely treated. Overall, the effect of treatment could be obtained in 41 patient (82%) among 50 hepatoma patient. Conclusively Ho-166 is thought to be a compromising agent in the treatment of hepatocellular carcinoma and one of therapeutic modality, if it is established internally and world-wide. In the future, the popular percutaneous ethanol injection method will be replaced to this method. 19 refs., 1 tabs., 14 figs. (author)

  1. Factors affecting de novo urinary retention after Holmium laser enucleation of the prostate.

    Directory of Open Access Journals (Sweden)

    Sung Han Kim

    Full Text Available OBJECTIVE: Patients can experience urinary retention (UR after Holmium laser enucleation of the prostate (HoLEP that requires bladder distension during the procedure. The aim of this retrospective study is to identify factors affecting the UR after HoLEP. MATERIALS AND METHODS: 336 patients, which underwent HoLEP for a symptomatic benign prostatic hyperplasia between July 2008 and March 2012, were included in this study. Urethral catheters were routinely removed one or two days after surgery. UR was defined as the need for an indwelling catheter placement following a failure to void after catheter removal. Demographic and clinical parameters were compared between the UR (n = 37 and the non-urinary retention (non-UR; n = 299 groups. RESULTS: The mean age of patients was 68.3 (±6.5 years and the mean operative time was 75.3 (±37.4 min. Thirty seven patients (11.0% experienced a postoperative UR. UR patients voided catheter free an average of 1.9 (±1.7 days after UR. With regard to the causes of UR, 24 (7.1% and 13 (3.9% patients experienced a blood clot-related UR and a non-clot related UR respectively. Using multivariate analysis (p0.05. CONCLUSIONS: De novo UR after HoLEP was found to be self-limited and it was not related to learning curve, patient age, diabetes, or operative time. Efficient morcellation and careful control of bleeding, which reduces clot formation, decrease the risk of UR after HoLEP.

  2. Holmium laser urethrotomy for treatment of traumatic stricture urethra: a review of 78 patients.

    Science.gov (United States)

    Hussain, Manzoor; Lal, Murli; Askari, Syed Hasan; Hashmi, Altaf; Rizvi, Syed Adibul Hasan

    2010-10-01

    To evaluate the efficacy and long-term results of laser urethrotomy as minimally invasive treatment for traumatic stricture urethra. Between January 2006 and June 2008, 78 male patients were treated with Holmium Laser urethrotomy. 16 Fr urethroscope was used through which 600um laser fiber was introduced through side channel. Stricture was visualized and incised at 12 o'clock position with energy set at 1500-2000 MJ at pulse rate of 10-12. Two other incisions were given at 2 and 10 o'clock positions. Further ablation was done till 16Fr Foley's catheter was passed. Patients were followed in a stricture clinic. Patients age ranged from 15-73 years. All strictures were due to trauma, Road traffic accident in 40 (52%) post catheter trauma 4 (5%), fall as ride 27 (35%) and failed urethroplasty 7 (8%). Site of stricture was bulbar 57 (73%), bulbomembranous 16 (20%) and membranoprostatic 5 (2.5%). Length of stricture ranged from 0.8-2.5 cms. At 3 months follow-up, 60 (77%) patients remained catheter and symptoms free while 18 (23%) developed recurrence of stricture but at the end of 36 months follow-up success rate decreased to 47 (60%). Among those who developed re-strictures, 6 ( 7.6%) had 2nd sitting laser while 4 (5.1%) had urethroplasty, and others were on intermittent dilatation. Immediate complications were sepsis 10 (13%), extravasation 2 (4%), failed urethrotomy 2 (4%) and mild haematuria 3 (5.8%). Hospital stay ranged from day care to 3 days. Laser urethrotomy is minimally invasive and an effective treatment for short strictures in bulbarurethra. The recurrence rate is 40% in the long-term follow-up and is more commonly seen in completely obliterated strictures.

  3. Holmium laser enucleation of the prostate and retropubic prostatic adenomectomy: morbidity analysis and anesthesia considerations.

    Science.gov (United States)

    Soto-Mesa, D; Amorín-Díaz, M; Pérez-Arviza, L; Fernández-Pello Montes, S; Martín-Huéscar, A

    2015-11-01

    Holmium laser enucleation of the prostate (HoLEP) is an alternative to prostatic adenomectomy for the surgical treatment of benign prostatic hypertrophy. We analyzed our learning curve for this technique, and we compared it in a secondary manner with prostatic adenomectomy. A retrospective comparative study was conducted that included the first 100 cases of HoLEP performed in our center and the latest 50 cases of retropubic adenomectomy. We collected data on the patients, the surgery, the anesthesia, the perioperative variables, the anesthesia complications and the postoperative variables, with a 6-month follow-up. We analyzed the learning curve without mentors for HoLEP and compared the characteristics of HoLEP in 2 separate phases (learning and stabilization phases) with the latest retropubic prostatic adenomectomies performed. Intradural anesthesia was the most common technique. The transfusion needs, length of stay (P<.01) and postoperative morbidity were lower for HoLEP than for adenomectomy. However, the retropubic adenomectomy group had larger initial prostate volumes (P<.001) and shorter surgical times (P<.001). Better surgical performance (P<.001) and a lower incidence of complications were observed in the HoLEP-B group (once the learning curve had been overcome) compared with the HoLEP-A group. In our center, HoLEP was introduced as a valid alternative to open retropubic adenomectomy, with excellent results in terms of morbidity and reduced hospital stay. In terms of the learning curve, we consider that approximately 50 patients (without mentor) is an appropriate cutoff. Local anesthesia is a good choice for the anesthesia technique. Copyright © 2014 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

  4. Holmium laser urethrotomy for treatment of traumatic stricture urethra: A review of 78 patients

    International Nuclear Information System (INIS)

    Hussain, M.; Lal, M.; Askari, S.H.; Hashmi, A.; Rizvi, S.A.H.

    2010-01-01

    To evaluate the efficacy and long-term results of laser urethrotomy as minimally invasive treatment for traumatic stricture urethra. Methods: Between January 2006 and June 2008, 78 male patients were treated with Holmium Laser urethrotomy. 16 Fr urethroscope was used through which 600um laser fiber was introduced through side channel. Stricture was visualized and incised at 12 o'clock position with energy set at 1500-2000 MJ at pulse rate of 10-12. Two other incisions were given at 2 and 10 o'clock positions. Further ablation was done till 16 Fr Foley's catheter was passed. Patients were followed in a stricture clinic. Results: Patients age ranged from 15-73 years. All strictures were due to trauma, Road traffic accident in 40(52%) post catheter trauma 4(5%), fall as ride 27(35%) and failed urethroplasty 7(8%). Site of stricture was bulbar 57(73%), bulbomembranous 16(20%) and membranoprostatic 5(2.5%). Length of stricture ranged from 0.8-2.5 cms. At 3 months follow-up, 60(77%) patients remained catheter and symptoms free while 18(23%) developed recurrence of stricture but at the end of 36 months follow-up success rate decreased to 47 (60%). Among those who developed re-strictures, 6(7.6%) had second sitting laser while 4(5.1%) had urethroplasty, and others were on intermittent dilatation. Immediate complications were sepsis 10(13%), extravasation 2(4%), failed urethrotomy 2(4%) and mild haematuria 3(5.8%). Hospital stay ranged from day care to 3 days. Conclusion: Laser urethrotomy is minimally invasive and an effective treatment for short strictures in bulbar urethra. The recurrence rate is 40% in the long-term follow-up and is more commonly seen in completely obliterated strictures. (author)

  5. Effects of Intraluminal Irradiation with Holmium-166 for TIPS Stenosis: Experimental Study in a Swine Model

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ji Seon; Oh, Joo Hyeong; Kim, Deog Yoon; Park, Yong Koo; Kim, Soo Joong [Kyung Hee University Medical Center, Seoul (Korea, Republic of); Park, Sang Joon [Kang Dong Sacred Heart Hospital, Hallym University, Seoul (Korea, Republic of)

    2007-04-15

    We wanted to evaluate the effectiveness of intraluminal irradiation with Holmium-166 ({sup 166}Ho) for reducing the pseudointimal hyperplasia (PIH) in the transjugular intrahepatic portosystemic shunt (TIPS) tract in a swine model. TIPS was performed in 12 domestic pigs, after the creation of portal hypertension by intraportal injection of a mixture of N-butyl-2- cyanoacrylate (NBCA) and lipiodol. Five pigs first underwent intraluminal irradiation (30 Gy) in the parenchymal tract with using a {sup 166}Ho solution-filled balloon catheter, and this was followed by the placement of a nitinol stent in the TIPS tract. For the seven control pigs, the balloon was filled with saline and contrast media mixture. Two weeks later, follow-up portography and histological analysis were performed. TIPS was successfully performed in all twelve pigs with achieving artificially induced portal hypertension. Portography performed two weeks after TIPS showed the patent tracts in the TIPS tracts that were irradiated with {sup 166}Ho (5/5, 100%), whereas either completely (5/6, 83.3%) or partially (1/6, 16.7%) occluded TIPS were seen in the seven pigs of the nonirradiated control group, except in one pig that experienced periprocedural death due to bleeding. Histological analysis showed a statistically significant difference for the maximal PIH (irradiated: 32.8%, nonirradiated: 76.0%, p < 0.001) between the two groups. Intraluminal irradiation with 30 Gy of {sup 166}Ho for TIPS significantly improved the TIPS patency in a swine model of portal hypertension during a 2- week period of follow-up.

  6. Gamma spectrometry and chemical characterization of bioactive glass seeds with Holmium-166 for oncological implants

    International Nuclear Information System (INIS)

    Valente, Eduardo S.

    2009-01-01

    Bioactive glass seeds synthesized by the sol-gel technique with Si:Ho:Ca composition with natural holmium incorporated were irradiated in the TRIGA type nuclear reactor IPR-R1 at 100kW, in the central thimble where the thermal neutron flux is 2.8x10 12 n/cm 2 .s and the epithermal neutron flux is 2.6 X 10 11 n/cm 2 .s . After an 8 hour irradiation time, with an induced activity close to 110MBq/seed, a set of seeds was submitted to Gamma Spectrometry Analysis in a counting system with an HPGe detector, ORTEC electronic instrumentation and a Camberra Multichannel Analyser, to determine all radionuclides present on the sample as well as its individual activities. Special attention was paid on the discrimination of Si, 40 Ca, 44 Ca, C and Ho as the other expected elements like 48 Ca, 2 H and 18 O were present in traces or have very short half-lives. The second sample was submitted to Plasma spectrometry to determine the 166 Ho concentration in weight. The third sample was submitted to an X-ray spectrometry in a JEOL-JXA-8900RL equipment to determine its qualitative chemical composition, in order to evaluate impurities and nominal composition. It was determined that most of the activity, after decaying of short half-life elements, was due to 166 Ho present on the sample, with a well characterized β and gamma spectra. The homogeneity of the seeds was tested on the X-ray spectrometry, and verified that there is no discrepancy in composition from distinct seeds or in a same seed. The results are relevant on the investigation of the viability of producing 166 Ho radioactive seeds for oncological implants. (author)

  7. Next generation Er:YAG fractional ablative laser

    Science.gov (United States)

    Heinrich, A.; Vizhanyo, A.; Krammer, P.; Summer, S.; Gross, S.; Bragagna, T.; Böhler, C.

    2011-03-01

    Pantec Biosolutions AG presents a portable fractional ablative laser system based on a miniaturized diode pumped Er:YAG laser. The system can operate at repetition rates up to 500 Hz and has an incorporated beam deflection unit. It is smaller, lighter and cost efficient compared to systems based on lamp pumped Er:YAG lasers and incorporates a skin layer detection to guarantee precise control of the microporation process. The pulse parameters enable a variety of applications in dermatology and in general medicine, as demonstrated by first results on transdermal drug delivery of FSH (follicle stimulating hormone).

  8. CW Yb:YAG LASER FOR PORTABLE MEASURING SYSTEMS

    Directory of Open Access Journals (Sweden)

    A. M. Ivashko

    2014-01-01

    Full Text Available The theoretical and experimental results of longitudinally continuous-wave diode-pumped Yb:Y3Al5O12 (YAG laser performance for compact field-condition measuring systems were demonstrated. Optimization of laser setup in terms of operation condition in the range of -40 ˚С – +65 ˚С without active thermal stabilization was carried out. Using Yb (10 ат.%:YAG crystal with the length of 3 mm the maximal output power more than 2 W was obtained in the whole of temperature range.

  9. Laser beam diagnostics for kilowatt power pulsed YAG laser

    International Nuclear Information System (INIS)

    Liu, Yi; Leong, Keng H.

    1992-01-01

    There is a growing need for high power YAG laser beam diagnostics with the recent introduction of such lasers in laser material processing. In this paper, we will describe the use of a commercially available laser beam analyzer (Prometec) to profile the laser beam from a 1600 W pulsed Nd:YAG laser that has a 1 mm fiber optic beam delivery system. The selection of laser pulse frequency and pulse width for the measurement is discussed. Laser beam propagation parameters by various optical components such as fibers and lenses can be determined from measurements using this device. The importance of such measurements will be discussed

  10. Wideband thulium–holmium-doped fiber source with combined forward and backward amplified spontaneous emission at 1600–2300 nm spectral band

    Czech Academy of Sciences Publication Activity Database

    Honzátko, Pavel; Baravets, Yauhen; Kašík, Ivan; Podrazký, Ondřej

    2014-01-01

    Roč. 39, č. 12 (2014), s. 3650-3653 ISSN 0146-9592 R&D Projects: GA ČR(CZ) GAP205/11/1840 Institutional support: RVO:67985882 Keywords : Bandwidth * Spontaneous emission * Holmium Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 3.292, year: 2014

  11. 2.05 µm holmium-doped all-fiber laser diode-pumped at 1.125 µm

    Science.gov (United States)

    Kir'yanov, A. V.; Barmenkov, Y. O.; Villegas Garcia, I.

    2017-08-01

    We report a holmium-doped all-fiber laser oscillating at ~2.05 µm in continuous wave at direct in-core pumping by a 1.125 µm laser diode. Two types of home-made holmium-doped alumino-germano-silicate fiber (HDF), differentiated in the Ho3+ doping level, were fabricated to implement the laser, for revealing the effect of Ho3+ concentration upon the laser output. Firstly, the fibers were characterized thoroughly from the material and optical viewpoints. Then, laser action with both HDFs was assessed using the simplest Fabry-Perot cavity, assembled by a couple of spectrally adjusted fiber Bragg gratings, also made-in-house. In the best case, when using the lower-doped HDF of proper length (1.4 m), low threshold (~370 mW) and moderate slope efficiency (~13%) of ~2.05 µm lasing were obtained at 1.125 µm diode pumping. Long-term stability, high brightness, low noise, and purely CW operation are shown to be the laser’s attractive features. Yet, when utilizing the heavier-doped HDF, laser output is revealed to be overall worse, with a possible reason being the deteriorating Ho3+ concentration-related effects.

  12. Safety analysis of holmium-166 microsphere scout dose imaging during radioembolisation work-up. A cohort study

    Energy Technology Data Exchange (ETDEWEB)

    Braat, Arthur J.A.T.; Prince, Jip F.; Rooij, Rob van; Bruijnen, Rutger C.G.; Bosch, Maurice A.A.J. van den; Lam, Marnix G.E.H. [University Medical Center Utrecht, Department of Radiology and Nuclear Medicine, Utrecht (Netherlands)

    2018-03-15

    Radioembolisation is generally preceded by a scout dose of technetium-99m-macroaggregated albumin to estimate extrahepatic shunting of activity. Holmium-166 microspheres can be used as a scout dose (±250 MBq) and as a therapeutic dose. The general toxicity of a holmium-166 scout dose ({sup 166}Ho-SD) and safety concerns of an accidental extrahepatic deposition of {sup 166}Ho-SD were investigated. All patients who received a {sup 166}Ho-SD in our institute were reviewed for general toxicity and extrahepatic depositions. The absorbed dose in extrahepatic tissue was calculated on SPECT/CT and correlated to clinical toxicities. In total, 82 patients were included. No relevant clinical toxicity occurred. Six patients had an extrahepatic deposition of {sup 166}Ho-SD (median administered activity 270 MBq). The extrahepatic depositions (median activity 3.7 MBq) were located in the duodenum (3x), gastric fundus, falciform ligament and the lesser curvature of the stomach, and were deposited in a median volume of 15.3 ml, which resulted in an estimated median absorbed dose of 3.6 Gy (range 0.3-13.8 Gy). No adverse events related to the extrahepatic deposition of the {sup 166}Ho-SD occurred after a median follow-up of 4 months (range 1-12 months). These results support the safety of 250 MBq {sup 166}Ho-SD in a clinical setting. (orig.)

  13. The application of x-ray spectrometry to isotopic-source activation analysis of dysprosium and holmium

    International Nuclear Information System (INIS)

    Pillay, A.E.; Mboweni, R.C.M.

    1990-01-01

    A novel aspect of activation analysis is described for the determination of dysprosium and holmium at low concentrations. The method involves the measurement of K x-rays from radionuclides produced by thermal neutron activation using a 1 mg 252 Cf source. The basis for elemental selection depends largely on the demand for analysis and on the existence of favourable nuclear properties for the production of a practicable x-ray yield. A full appraisal of the analytical potential of the method is presented with particular emphasis on its application to geological matrices. The sensitivity was optimised by employing a detector that was particularly effective at photon energies below 150 keV. Analytical conditions are demonstrated for the elements of interest over a wide range of concentrations in small powdered samples. The investigation formed the basis of a feasibility study to establish if the application could be developed for the routine off-line determination of dysprosium and holmium using an isotopic-neutron source. (author)

  14. Field-expedient screening and injury risk algorithm categories as predictors of noncontact lower extremity injury.

    Science.gov (United States)

    Lehr, M E; Plisky, P J; Butler, R J; Fink, M L; Kiesel, K B; Underwood, F B

    2013-08-01

    In athletics, efficient screening tools are sought to curb the rising number of noncontact injuries and associated health care costs. The authors hypothesized that an injury prediction algorithm that incorporates movement screening performance, demographic information, and injury history can accurately categorize risk of noncontact lower extremity (LE) injury. One hundred eighty-three collegiate athletes were screened during the preseason. The test scores and demographic information were entered into an injury prediction algorithm that weighted the evidence-based risk factors. Athletes were then prospectively followed for noncontact LE injury. Subsequent analysis collapsed the groupings into two risk categories: Low (normal and slight) and High (moderate and substantial). Using these groups and noncontact LE injuries, relative risk (RR), sensitivity, specificity, and likelihood ratios were calculated. Forty-two subjects sustained a noncontact LE injury over the course of the study. Athletes identified as High Risk (n = 63) were at a greater risk of noncontact LE injury (27/63) during the season [RR: 3.4 95% confidence interval 2.0 to 6.0]. These results suggest that an injury prediction algorithm composed of performance on efficient, low-cost, field-ready tests can help identify individuals at elevated risk of noncontact LE injury. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  15. Optical properties and laser oscillations of highly neodymium-doped YAG ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Shoji, Ichiro; Kurimura, Sunao; Sato, Yoichi; Taira, Takunori [Laser Research Center, Institute for Molecular Science, Okazaki, Aichi (Japan); Ikesue, Akio [Japan Fine Ceramics Center, Nagoya, Aichi (Japan); Yoshida, Kunio [Institute of Laser Engineering, Osaka Institute of Technology, Osaka (Japan)

    2000-03-01

    Diode-pumped microchip laser oscillation of highly Nd{sup 3+}-doped polycrystalline YAG ceramics has been succeeded. It is found that the loss of a 2.4 at. % neodymium-doped ceramic YAG is as low as that of a 0.9 at. % Nd:YAG single crystal. From a 4.8 at. % Nd:YAG ceramic microchip, 2.3 times higher laser output power is obtained than that from a 0.9 at. % Nd:YAG single crystal microchip. (author)

  16. Optical properties and laser oscillations of highly neodymium-doped YAG ceramics

    International Nuclear Information System (INIS)

    Shoji, Ichiro; Kurimura, Sunao; Sato, Yoichi; Taira, Takunori; Ikesue, Akio; Yoshida, Kunio

    2000-01-01

    Diode-pumped microchip laser oscillation of highly Nd 3+ -doped polycrystalline YAG ceramics has been succeeded. It is found that the loss of a 2.4 at. % neodymium-doped ceramic YAG is as low as that of a 0.9 at. % Nd:YAG single crystal. From a 4.8 at. % Nd:YAG ceramic microchip, 2.3 times higher laser output power is obtained than that from a 0.9 at. % Nd:YAG single crystal microchip. (author)

  17. Surface structure investigations using noncontact atomic force microscopy

    International Nuclear Information System (INIS)

    Kolodziej, J.J.; Such, B.; Goryl, M.; Krok, F.; Piatkowski, P.; Szymonski, M.

    2006-01-01

    Surfaces of several A III B V compound semiconductors (InSb, GaAs, InP, InAs) of the (0 0 1) orientation have been studied with noncontact atomic force microscopy (NC-AFM). Obtained atomically resolved patterns have been compared with structural models available in the literature. It is shown that NC-AFM is an efficient tool for imaging complex surface structures in real space. It is also demonstrated that the recent structural models of III-V compound surfaces provide a sound base for interpretation of majority of features present in recorded patterns. However, there are also many new findings revealed by the NC-AFM method that is still new experimental technique in the context of surface structure determination

  18. Modeling noncontact atomic force microscopy resolution on corrugated surfaces

    Directory of Open Access Journals (Sweden)

    Kristen M. Burson

    2012-03-01

    Full Text Available Key developments in NC-AFM have generally involved atomically flat crystalline surfaces. However, many surfaces of technological interest are not atomically flat. We discuss the experimental difficulties in obtaining high-resolution images of rough surfaces, with amorphous SiO2 as a specific case. We develop a quasi-1-D minimal model for noncontact atomic force microscopy, based on van der Waals interactions between a spherical tip and the surface, explicitly accounting for the corrugated substrate (modeled as a sinusoid. The model results show an attenuation of the topographic contours by ~30% for tip distances within 5 Å of the surface. Results also indicate a deviation from the Hamaker force law for a sphere interacting with a flat surface.

  19. Proceedings of the Second Noncontact Temperature Measurement Workshop

    Science.gov (United States)

    Hale, Robert R. (Editor)

    1989-01-01

    The state of the art in noncontact temperature measurement (NCTM) technology was reviewed and the NCTM requirements of microgravity materials processing community identified. The workshop included technical presentations and discussions which ranged from research on advanced concepts for temperature measurement to laboratory research and development regarding measurement principles and state-of-the-art engineering practices for NCTM methodology in commercial and industrial applications. Technical presentations were made concerning: NCTM needs as perceived by several NASA centers, recent ground-based NCT, research and development of industry, NASA, academia, and selected national laboratories, work-in-progress communication, and technical issues of the implementation of temperature measurement in the space environment to facilitate future U.S. materials science investigations.

  20. Non-contact measurement of rotation angle with solo camera

    Science.gov (United States)

    Gan, Xiaochuan; Sun, Anbin; Ye, Xin; Ma, Liqun

    2015-02-01

    For the purpose to measure a rotation angle around the axis of an object, a non-contact rotation angle measurement method based on solo camera was promoted. The intrinsic parameters of camera were calibrated using chessboard on principle of plane calibration theory. The translation matrix and rotation matrix between the object coordinate and the camera coordinate were calculated according to the relationship between the corners' position on object and their coordinates on image. Then the rotation angle between the measured object and the camera could be resolved from the rotation matrix. A precise angle dividing table (PADT) was chosen as the reference to verify the angle measurement error of this method. Test results indicated that the rotation angle measurement error of this method did not exceed +/- 0.01 degree.

  1. Non-contact feature detection using ultrasonic Lamb waves

    Science.gov (United States)

    Sinha, Dipen N [Los Alamos, NM

    2011-06-28

    Apparatus and method for non-contact ultrasonic detection of features on or within the walls of hollow pipes are described. An air-coupled, high-power ultrasonic transducer for generating guided waves in the pipe wall, and a high-sensitivity, air-coupled transducer for detecting these waves, are disposed at a distance apart and at chosen angle with respect to the surface of the pipe, either inside of or outside of the pipe. Measurements may be made in reflection or transmission modes depending on the relative position of the transducers and the pipe. Data are taken by sweeping the frequency of the incident ultrasonic waves, using a tracking narrow-band filter to reduce detected noise, and transforming the frequency domain data into the time domain using fast Fourier transformation, if required.

  2. Noncontact power/interrogation system for smart structures

    Science.gov (United States)

    Spillman, William B., Jr.; Durkee, S.

    1994-05-01

    The field of smart structures has been largely driven by the development of new high performance designed materials. Use of these materials has been generally limited due to the fact that they have not been in use long enough for statistical data bases to be developed on their failure modes. Real time health monitoring is therefore required for the benefits of structures using these materials to be realized. In this paper a non-contact method of powering and interrogating embedded electronic and opto-electronic systems is described. The technique utilizes inductive coupling between external and embedded coils etched on thin electronic circuit cards. The technique can be utilized to interrogate embedded sensors and to provide > 250 mW for embedded electronics. The system has been successfully demonstrated with a number of composite and plastic materials through material thicknesses up to 1 cm. An analytical description of the system is provided along with experimental results.

  3. Evaluation of a Noncontact, Alternative Mosquito Repellent Assay System.

    Science.gov (United States)

    Tisgratog, Rungarun; Kongmee, Monthathip; Sanguanpong, Unchalee; Prabaripai, Atchariya; Bangs, Michael J; Chareonviriyaphap, Theeraphap

    2016-09-01

    A novel noncontact repellency assay system (NCRAS) was designed and evaluated as a possible alternative method for testing compounds that repel or inhibit mosquitoes from blood feeding. Deet and Aedes aegypti were used in a controlled laboratory setting. Using 2 study designs, a highly significant difference were seen between deet-treated and untreated skin placed behind the protective screens, indicating that deet was detected and was acting as a deterrence to mosquito landing and probing behavior. However, a 2nd study showed significant differences between protected (behind a metal screen barrier) and unprotected (exposed) deet-treated forearms, indicating the screen mesh might restrict the detection of deet and thus influences landing/biting response. These findings indicate the prototype NCRAS shows good promise but requires further evaluation and possible modification in design and testing protocol to achieve more desirable operational attributes in comparison with direct skin-contact repellency mosquito assays.

  4. Non-contact biopotential sensor for remote human detection

    Energy Technology Data Exchange (ETDEWEB)

    Mahdi, A E [Department of Electronic and Computer Engineering, University of Limerick, Limerick (Ireland); Faggion, L, E-mail: hussain.mahdi@ul.ie, E-mail: lorenzo.faggion@jrc.ec.europa.eu [Joint Research Centre of the European Commission, Institute for the Protection and Safety of the Citizen, Ispra (Italy)

    2011-08-17

    This paper describes a new low-cost, low-noise displacement current sensor developed for non-contact measurements of human biopotentials and well suited for detection of human presence applications. The sensor employs a simple, improvised transimpedance amplifier that eliminates the need for ultra high values resistors normally needed in current amplifiers required for this type of measurements. The sensor provides an operational bandwidth of 0.5 - 250 Hz, and a noise level of 7.8{mu}V{radical}Hz at 1 Hz down to 30nV/{radical}Hz at 1 kHz. Reported experimental results demonstrate the sensor's capability in measuring heart related biopotentials within 0.5m off-body distance, and muscle related biopotentials within 10m no obstacles off-body distance, and 5m off-body distance with a concrete wall in between.

  5. Numerical analysis of the non-contacting gas face seals

    Science.gov (United States)

    Blasiak, S.

    2017-08-01

    The non-contacting gas face seals are used in high-performance devices where the main requirements are safety and reliability. Compliance with these requirements is made possible by careful research and analysis of physical processes related to, inter alia, fluid flow through the radial gap and ring oscillations susceptible to being housed in the enclosure under the influence of rotor kinematic forces. Elaborating and developing mathematical models describing these phenomena allows for more and more accurate analysis results. The paper presents results of studies on stationary ring oscillations made of different types of materials. The presented results of the research allow to determine which of the materials used causes the greatest amplitude of the vibration of the system fluid film-working rings.

  6. Changes of retinal light sensitivity after YAG-laser capsulotomy

    International Nuclear Information System (INIS)

    Pahor, D.; Gracner, B.

    2003-01-01

    The aim of this prospective study was to investigate the changes of retinal light sensitivity of central visual field in patients with posterior capsule opacification (PCO) after YAG-laser capsulotomy. Our study includes 18 eyes ( 18 patients) with PCO after phacoemulsification and intraocular lens implantation. In all patients YAG-laser capsulotomy was performed. In all patients, a threshold visual field analysis was carried out with the C 30-2 program of the automated Humphrey Field Analyzer before and one month after the procedure. In all patients a significant improvement of visual acuity was observed one month after capsulotomy (p 0.00004). One month after YAG-laser treatment, a significant improvement of retinal light sensitivity in the central visual field was also observed. The average MD (mean deviation) before the procedure was -6.88 db (±3.9, max. -11.7, min. 2.17) and after the procedure --4.58 db (±4.37, max. -10.87, min. +0.51). The improvement in MD was statistically significant (p = 0.00475). No correlation was established between the improvement of retinal light sensitivity and patient age or the size of capsulotomy. Our study shows that the improvement of retinal light sensitivity is significant after YAG-laser capsulotomy and does not depend on patient age or capsulotomy size. (author)

  7. Tunable, diode side-pumped Er:YAG laser

    Science.gov (United States)

    Hamilton, C.E.; Furu, L.H.

    1997-04-22

    A discrete-element Er:YAG laser, side pumped by a 220 Watt peak-power InGaAs diode array, generates >500 mWatts at 2.94 {micro}m, and is tunable over a 6 nm range near about 2.936 {micro}m. The oscillator is a plano-concave resonator consisting of a concave high reflector, a flat output coupler, a Er:YAG crystal and a YAG intracavity etalon, which serves as the tuning element. The cavity length is variable from 3 cm to 4 cm. The oscillator uses total internal reflection in the Er:YAG crystal to allow efficient coupling of the diode emission into the resonating modes of the oscillator. With the tuning element removed, the oscillator produces up to 1.3 Watts of average power at 2.94 {micro}m. The duty factor of the laser is 6.5% and the repetition rate is variable up to 1 kHz. This laser is useful for tuning to an atmospheric transmission window at 2.935 {micro}m (air wavelength). The laser is also useful as a spectroscopic tool because it can access several infrared water vapor transitions, as well as transitions in organic compounds. Other uses include medical applications (e.g., for tissue ablation and uses with fiber optic laser scalpels) and as part of industrial effluent monitoring systems. 4 figs.

  8. Application of YAG laser cladding to the flange seating surface

    International Nuclear Information System (INIS)

    Nakanishi, Koki; Ninomiya, Kazuyuki; Nezaki, Koji

    1999-01-01

    Stainless cladding on carbon steel is usually conducted by shielded metal arc welding (SMAW) or gas tungsten arc welding (GTAW). YAG ( Yttrium-Aluminum-Garnet) laser welding is superior to these methods of welding in the following respects : (1) The heat affected zone (HAZ) is narrower and there is less distortion. (2) YAG laser cladding has the required chemical compositions, even with possibly fewer welding layers under controlled dilution. (3) Greater welding speed. YAG laser cladding application to vessel flange seating surfaces was examined in this study and the results are discussed. The following objectives were carried out : (1) Determination of welding conditions for satisfactory cladding layers and (2) whether cladding would be adequately possible at a cornered section of a stair-like plate, assuming actual flange shape. (3) Measurement of welding distortion and heat affected zone in carbon steel. The welding conditions for producing no-crack deposit with low dilution in carbon steel were clarified and welding by which cladding at cornered section would be possible was achieved. welding distortion by YAG laser was found less than with GTAW and HAZ made by first layer welding could be tempered appropriately by second layer welding. (author)

  9. Nd-YAG laser welding of bare and galvanised steels

    International Nuclear Information System (INIS)

    Kennedy, S.C.; Norris, I.M.

    1989-01-01

    Until recently, one of the problems that has held back the introduction of lasers into car body fabrication has been the difficulty of integrating the lasers with robots. Nd-YAG laser beams can be transmitted through fibre optics which, as well as being considerably easier to manipulate than a mirror system, can be mounted on more lightweight accurate robots. Although previously only available at low powers, recent developments in Nd-YAG laser technology mean that lasers of up to 1kW average power will soon be available, coupled to a fibre optic beam delivery system. The increasing usage of zinc coated steels in vehicle bodies has led to welding problems using conventional resistance welding as well as CO 2 laser welding. The use of Nd-YAG lasers may be able to overcome these problems. This paper outlines work carried out at The Welding Institute on a prototype Lumonics 800W pulsed Nd-YAG laser to investigate its welding characteristics on bare and zinc coated car body steels

  10. Neodymium:YAG laser cutting of intraocular lens haptics.

    Science.gov (United States)

    Gorn, R A; Steinert, R F

    1985-11-01

    Neodymium:YAG laser cutting of polymethylmethacrylate and polypropylene anterior chamber and posterior chamber intraocular lens haptics was studied in terms of ease of transection and physical structure of the cut areas as seen by scanning electron microscopy. A marked difference was discovered, with the polymethylmethacrylate cutting easily along transverse planes, whereas the polypropylene resisted cutting along longitudinal fibers. Clinical guidelines are presented.

  11. Pulsed Nd:YAG laser beam drilling: A review

    Science.gov (United States)

    Gautam, Girish Dutt; Pandey, Arun Kumar

    2018-03-01

    Laser beam drilling (LBD) is one of non contact type unconventional machining process that are employed in machining of stiff and high-strength materials, high strength temperature resistance materials such as; metal alloys, ceramics, composites and superalloys. Most of these materials are difficult-to-machine by using conventional machining methods. Also, the complex and precise holes may not be obtained by using the conventional machining processes which may be obtained by using unconventional machining processes. The laser beam drilling in one of the most important unconventional machining process that may be used for the machining of these materials with satisfactorily. In this paper, the attention is focused on the experimental and theoretical investigations on the pulsed Nd:YAG laser drilling of different categories of materials such as ferrous materials, non-ferrous materials, superalloys, composites and Ceramics. Moreover, the review has been emphasized by the use of pulsed Nd:YAG laser drilling of different materials in order to enhance productivity of this process without adverse effects on the drilled holes quality characteristics. Finally, the review is concluded with the possible scope in the area of pulsed Nd:YAG laser drilling. This review work may be very useful to the subsequent researchers in order to give an insight in the area of pulsed Nd:YAG laser drilling of different materials and research gaps available in this area.

  12. Preparation and properties of Pr /Ce :YAG phosphors using ...

    Indian Academy of Sciences (India)

    2015-09-01

    Sep 1, 2015 ... [3] transparent ceramics for high power solid-state lasers and Ce:YAG ... and CO2−. 3 . ... be controlled to guarantee that all the metal ions are simul- taneously .... of hydrogen bonding interaction can lead to more serious.

  13. [Correlation between Goldmann and non-contact tonometry based on corneal thickness].

    Science.gov (United States)

    Schepens, G; Urier, N; Bechetoille, A; De Potter, P

    2001-01-01

    In this transversal study, we measure the intra ocular pressure by means of the Goldmann tonometer and a Non-Contact tonometer along with the central cornea thickness in 136 eyes of 73 patients. The statistical analysis of the collected data doesn't allow us to establish a correlation between the variation of the corneal thickness and the difference between the Goldmann tonometer and Non-Contact tonometer measures. The relative precision of the Non-Contact tonometer compared with the Goldmann tonometer doesn't seem influenced by the central cornea thickness.

  14. [Experimental results of erbium:YAG laser vitrectomy].

    Science.gov (United States)

    Mrochen, M; Petersen, H; Wüllner, C; Seiler, T

    1998-01-01

    Vitrectomy performed by conventional guillotine devices includes the risk of mechanical damage to retina as well as other ocular structures. The present study aims to investigate the efficacy of the Er:YAG laser for vitreous liquefaction. Vitreous liquefaction by means of Er:YAG laser pulses was performed using a special handpiece. The output of an Er:YAG laser operating at 2.94 microns was coupled into a ZrF optical fibre (length 2 m) which ended inside a cavity located at the quartz tip (diameter 320 microns) of the handpiece where tissue ablation took place. The viscosity of the liquefied vitreous was determined by rotation viscosimetry and compared to liquefied vitreous obtained by mechanical vitrectomy. In addition, the aspiration flow (ml/min) was correlated to the repetition/cutting rate of the laser and the cutter. The temperature rise at the handpiece was recorded with a micro thermocouple. The cutting threshold was determined to 5 mJ +/- 3 mJ at a pulse duration of 200 microseconds. The viscosity of the vitreous liquefied with the Er:YAG laser was 31 +/- 10 mPa s which is similar to the results of mechanical vitrectomy (42 +/- 19 mPa s) but significant less than that of normal vitreous (880 +/- 280 mPa s). The aspiration of the laser handpiece in dependence to the repetition rate increases linear up to 2.6 ml/min at 30 Hz. The temperature increase at the handpiece was < 1 K under vitrectomy conditions (aspiration and irrigation) with an averaged laser power of 0.3 W (10 mJ at 30 Hz). The decreased vacuum forces used by the laser vitrectomy system may result in less mechanical stress to the retina as well as intravitreal structures which may be attached to it. An Er:YAG laser vitrectomy system may offer the potential of fewer complications during vitrectomy.

  15. Therapeutic application of new holmium-166 chitosan complex in malignant and benign diseases

    International Nuclear Information System (INIS)

    Park, K.B.; Kim, Y.M.; Shin, B.C.; Kim, J.R.; Ryu, J.M.; Lim, S.M.

    1998-01-01

    The new holmium-166 chitosan complex ( 166 Ho-CHICO, DW- 166 HC) was prepared by reacting the aqueous acidic solution of chitosan with 166 Ho(NO 3 ) 3 at room temperature with quantitative labelling yield. The progress of the reaction and labelling yield were determined by instant this layer chromatography using silicic acid impregnated glass fiber (ITLC-SA) and developing solvent of MeOH:H 2 O:HAC (49:49:2). The high labelling yield of more than 99% was obtained by reacting chitosan solution (35 mg/4 ml) with 166 Ho(NO 3 ) 3 in which 7 mg of 165 Ho+ 166 Ho were contained as a maximum content. The labelling yield was highly dependent on the pH of the chitosan solution. The optimal labelling could be obtained at pH 2.5∼3.5 The characteristics of 166 Ho-CHICO were similar to those of chitosan, which is biocompatible, biodegradable, non-toxic, soluble and viscous in acidic condition but geltatinuous at pH 6.0 and precipitating in alkaline conditions. 166 Ho-CHICO can be easily prepared by reconstituting freeze-dried chitosan (kit A) with 166 Ho(NO 3 ) 3 solution (kit B) just prior to use. After intrahepatic administration of 166 Ho-CHICO to male rats, the radioactivity concentrations in blood were low and the cumulative urinary and fecal excretion over a period of 0 to 72 hours were 0.53% and 0.54%, respectively. the radioactivity concentration in tissues and the whole-body autoradiography images showed that most of the administered radioactivity was localized at the administered site, and only slight radioactivity was detected from the liver, spleen, lungs, and bones. An autoradiograph after intratumoral administration of 166 Ho-CHICO showed that radioactivity was localized at the administered site of the lesion without distribution to other organs and tissues. A biodistribution study in normal rabbits with 166 Ho-CHICO showed that most of the radioactivities were retained in the knee joint with negligible extra leakage at 72 hours after intra

  16. Radiosynoviorthesis of knees by means of 166Ho-holmium-boro-macroaggregates.

    Science.gov (United States)

    Kraft, Otakar; Kaspárek, Richard; Ullmann, Vojtech; Melichar, Frantisek; Kropácek, Martin; Mirzajevova, Marcela

    2007-04-01

    The aim of this study was to evaluate adverse and therapeutic effects of applicated holmium-boro-macroaggregates (HBMAs) in the radiosynoviorthesis (RSO) of knees in patients suffering from chronic synovitis. We started RSO of the knees by means of a new radiopharmaceutical (RF) HBMA in patients with gonarthrosis, rheumatoid arthritis, chronic synovitis, psoriatic arthritis, and gout arthropathy. Seventeen (17) intra-articular injections were performed in 15 patients who were receiving a mean activity of 972 MBq (range, 904-1057) of 166Ho-HBMA. Patient inclusion to the study followed a series of inclusion and exclusion criterions. The patients were hospitalized for 3 days. Side-effects were evaluated during their hospital stay and again after 6-8 weeks. Static scintigraphy of knee joints and measurements of blood radioactivity were performed. Therapeutic effects were evaluated after 6-8 weeks and at 6 months. In 2 hours and 2 days following the application, we proved, by means of knee and inguinal scintigraphy, only insignificant radiopharmaceutical leakage from the joint cavity to the inguinal lymph nodes in 4 patients. In the treated patients, no serious adverse effects occurred. Nine (9) patients were without complaints, 4 patients had slight knee exudation, and 2 patients had great exudation. Therapeutic effects were as follows: 2 patients were without pain, 9 were with lower pain, 3 were with the same pain, and 1 patient was with increased pain. Joint motion was improved in 7 patients, remained the same in 7 patients, and was impaired in 1 patient. Analgesics consumption was lower in 5 patients, the same in 9 patients, and greater in 1 patient. Knee exudation was absent in 2 patients, lower in 4 patients, the same in 6 patients, and greater in 3 patients. In 3 patients it was necessary to do surgical RSO. This RF can extend the range of clinically used radiopharmaceuticals for RSO and to supplement space between 90Y with high energy and 186Re with 169Er with

  17. FT-Raman spectroscopic characterization of enamel surfaces irradiated with Nd:YAG and Er:YAG lasers

    Directory of Open Access Journals (Sweden)

    Sima Shahabi

    2016-12-01

    Full Text Available Background. Despite recent advances in dental caries prevention, caries is common and remains a serious health problem. Laser irradiation is one of the most common methods in preventive measures in recent years. Raman spectroscopy technique is utilized to study the microcrystalline structure of dental enamel. In this study, FT-Raman spectroscopy was used to evaluate chemical changes in enamel structure irradiated with Nd:YAG and Er:YAG lasers. Methods. We used 15 freshly-extracted, non-carious, human molars that were treated as follows: No treatment was carried out in group A (control group; Group B was irradiated with Er:YAG laser for 10 seconds under air and water spray; and Group C was irradiated with Nd:YAG laser for 10 seconds under air and water spray. After treatment, the samples were analyzed by FT-Raman spectroscopy. Results. The carbonate content evaluation with regard to the integrated area under the curve (1065/960 cm–1 exhibited a significant reduction in its ratio in groups B and C. The organic content (2935/960 cm-1 area exhibited a significant decrease after laser irradiation in group B and C. Conclusion. The results showed that the mineral and organic matrices of enamel structure were affected by laser irradiation; therefore, it might be a suitable method for caries prevention.

  18. In vitro study of morphological and chemical modification threshold of bovine dental enamel irradiated by the holmium laser

    International Nuclear Information System (INIS)

    Eduardo, Patricia Lerro de Paula

    2001-01-01

    The aim of this study is to investigate the Ho:YLF laser effects on the dental enamel surface with regards to its morphology, thermal variations during its irradiation in the pulp chamber and its increased resistance to demineralization through quantitative analysis of calcium and phosphorous atoms reactive concentrations in samples. Twenty samples of bovine enamel were used and divided in four groups: control - acidulated phosphate fluoride (APF) application followed by demineralization treatment with lactic acid; irradiation with Ho:YLF laser (100 J/cm 2 ) followed by APF topic application and demineralization treatment with lactic acid; irradiation with Ho:YLF laser (350 J/cm 2 ) followed by APF topic application and demineralization treatment with lactic acid: and irradiation with Ho:YLF laser ( 450 J/cm 2 ) followed by APF topic application and demineralization treatment with lactic acid. Ali samples were quantified according to their calcium and phosphorous atoms relative concentrations before and after the treatments above. X-Ray fluorescence spectrochemical analysis and scanning electron microscopy were carried out. It was observed an increase on the calcium and phosphorous atoms concentration ratio and therefore the enamel demineralization reduction as a result of the lactic acid treatment in the samples irradiated with the holmium laser followed by the APF application. In order to evaluate the feasibility of this study for clinical purposes, morphological changes caused by the holmium laser irradiation were analyzed. Such modifications were characterized by melted and re-solidified regions of the enamel with consequent changes on its permeability and solubility. Temperature changes of ten human pre-molars teeth irradiated with 350 J/cm 2 and 450 J/cm 2 were also monitored in the pulp chamber in real time. Temperature increases over 4,20 C did not occur. The results obtained from this study along with the results from previous researches developed at

  19. INNOVATIVE NON-CONTACT METROLOGY SOLUTIONS FOR LARGE OPTICAL TELESCOPES, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA has unique non-contact precision metrology requirements for dimensionally inspecting the global position and orientation of large and highly-polished...

  20. ChemCam-like Spectrometer for Non-Contact Measurements of Key Isotopes, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — This project addresses the need for a non-contact instrument capable of measuring the isotopic ratios O-18/O-16 and D/H from water ice and other solid materials...

  1. Freeform optics: a non-contact "test plate" for manufacturing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The goal of this NASA SBIR Phase I study is to determine the feasibility of measuring precision (fractional wave) freeform optics using non-contact areal (imaging)...

  2. 3D YAG laser cutting robot. 3 jigen YAG laser setsudan robot

    Energy Technology Data Exchange (ETDEWEB)

    Mukai, Y. (Matsushita Electric Industrial Co. Ltd., Osaka (Japan))

    1991-11-01

    The present status was introduced of three-dimensional processing by the YAG laser multi-articulation robot to introduce the focusing system. The lowering in locus accuracy of multi-articulation robot is caused by the accuracy and time of computation to interpolate the locus, response characteristics of servo system, and calibration problem of mechanical/structural system. Also as low in output power of laser, it has problem in focusing the energy in the radiating optical system. A focusing system, high in response velocity, is necessary in the processor to use the optical fiber in the optical transfer system. As processing and measuring at an identical spot, the present system can integrate the detection use electrode and nozzle so as to use an electrostatic capacity type sensor, high in response frequency. To avoid the interference with jig, etc., the nozzle of radiating unit was integrated with the detection use electrode so that development was made of height sensor, capable of executing the three-dimensional processing. The present robot is characterized by a standardized equipment of control system with a sliding shaft, independent of the operational shaft properly of robot in order to be exclusively used for the focusing. 9 figs.

  3. Evaluation in vitro of effects of Er:YAG and Nd:YAG lasers irradiation on root canal wall, by stereoscopy, scanning electron micrography and thermographic camera; Avaliacao in vitro dos efeitos da irradiacao laser de Er:YAG e Nd:YAG na parede dentinaria do canal radicular, sob observacao do estereoscopio, da micrografia eletronica e da camera termografica

    Energy Technology Data Exchange (ETDEWEB)

    Goya, Claudia

    2001-07-01

    This study was carried out to evaluate in vitro the effects of Nd:YAG laser and Er:YAG laser irradiation in the root canal wall by SEM, evaluating the apical leakage and the temperature changes during the laser irradiation. Seventy four extracted human teeth were used, they were instrumented and divided into seven groups of 10 teeth each. The teeth were evaluated through stereoscopy, by SEM, and with the thermographic camera. The Nd:YAG laser irradiation parameters were 100 mJ/p, 15 Hz, and Er:YAG laser were 160 mJ/p and 10 Hz, the irradiation was 4 times at 2 mm/sec speed, with 20 sec interval. The apical leakage was not observed in the teeth irradiated by Nd:YAG laser alone or in association with Er:YAG laser. However in the teeth irradiated only by the Er:YAG laser we observed a little leakage. By SEM observation the Nd:YAG laser irradiation showed melting and recrystallization in the dentin surface closing dentinal tubules, and in the samples irradiated by Er:Y AG laser a clean surface, opened dentinal tubules, and the combination by two lasers, showed melting covering some dentinal tubules The thermographic study found the temperature increase was not more than 6 deg C. This study showed the safety parameters applications of Er:YAG laser in association with Nd:YAG laser in root canal treatment, in order to not cause thermal damages to the periodontal tissues. (author)

  4. Corrosion Resistant Cladding by YAG Laser Welding in Underwater Environment

    International Nuclear Information System (INIS)

    Tsutomi Kochi; Toshio Kojima; Suemi Hirata; Ichiro Morita; Katsura Ohwaki

    2002-01-01

    It is known that stress-corrosion cracking (SCC) will occur in nickel-base alloys used in Reactor Pressure Vessel (RPV) and Internals of nuclear power plants. A SCC sensitivity has been evaluated by IHI in each part of RPV and Internals. There are several water level instrumentation nozzles installed in domestic BWR RPV. In water level instrumentation nozzles, 182 type nickel-base alloys were used for the welding joint to RPV. It is estimated the SCC potential is high in this joint because of a higher residual stress than the yield strength (about 400 MPa). This report will describe a preventive maintenance method to these nozzles Heat Affected Zone (HAZ) and welds by a corrosion resistant cladding (CRC) by YAG Laser in underwater environment (without draining a reactor water). There are many kinds of countermeasures for SCC, for example, Induction Heating Stress Improvement (IHSI), Mechanical Stress Improvement Process (MSIP) and so on. A YAG laser CRC is one of them. In this technology a laser beam is used for heat source and irradiated through an optical fiber to a base metal and SCC resistant material is used for welding wires. After cladding the HAZ and welds are coated by the corrosion resistant materials so their surfaces are improved. A CRC by gas tungsten arc welding (GTAW) in an air environment had been developed and already applied to a couple of operating plants (16 Nozzles). This method was of course good but it spent much time to perform because of an installation of some water-proof working boxes to make a TIG-weldability environment. CRC by YAG laser welding in underwater environment has superior features comparing to this conventional TIG method as follows. At the viewpoint of underwater environment, (1) an outage term reduction (no drainage water). (2) a radioactive exposure dose reduction for personnel. At that of YAG laser welding, (1) A narrower HAZ. (2) A smaller distortion. (3) A few cladding layers. A YAG laser CRC test in underwater

  5. Evaluation of anti-tuberculosis antibodies in healthy contact and non-contacts persons

    International Nuclear Information System (INIS)

    Aziz, N; Bukhari, M.H; Muneer, M; Tayyab, M; Chaudhry, N.A.

    2006-01-01

    This study was conducted to see the presence of the antimycobacterial antibodies in healthy household contacts of tuberculosis patients and healthy normal subjects who have never been in contact with tuberculosis patients. A total of 200 subjects, 120 with history of household contact and 80 without such history were included in the study. Routine Haematological investigations were performed and all the sera of 200 subjects were tested who 19M, 19G and IgA anti tuberculosis antibodies using ELISA technique. There was no difference in the average age of the household contacts and non-contacts. The complaints of pyrexia, night sweats and loss of weight was more in house hold contacts as compared to non-contacts. The awareness about BCG vaccination was equal among the household contacts and non-contacts. The combined serological positivity of the household contacts was 65.8% and the combined serological positivity for non-contacts was 34.1%. There was no statistically significant difference in the presence of 19M among household contacts as compared to non-contacts. However both IgG and 19A were present in significantly higher number of household contacts as compared to non contacts. This study concludes that the persons living in the house with a patient suffering from active pulmonary tuberculosis (household contact) have more chances of being infected with Mycobacterium tuberculosis as compared to the healthy non-contacts. (author)

  6. Hyperfine-Interaction-Driven Suppression of Quantum Tunneling at Zero Field in a Holmium(III) Single-Ion Magnet.

    Science.gov (United States)

    Chen, Yan-Cong; Liu, Jun-Liang; Wernsdorfer, Wolfgang; Liu, Dan; Chibotaru, Liviu F; Chen, Xiao-Ming; Tong, Ming-Liang

    2017-04-24

    An extremely rare non-Kramers holmium(III) single-ion magnet (SIM) is reported to be stabilized in the pentagonal-bipyramidal geometry by a phosphine oxide with a high energy barrier of 237(4) cm -1 . The suppression of the quantum tunneling of magnetization (QTM) at zero field and the hyperfine structures originating from field-induced QTMs can be observed even from the field-dependent alternating-current magnetic susceptibility in addition to single-crystal hysteresis loops. These dramatic dynamics were attributed to the combination of the favorable crystal-field environment and the hyperfine interactions arising from 165 Ho (I=7/2) with a natural abundance of 100 %. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Hyperfine-interaction-driven suppression of quantum tunneling at zero field in a holmium(III) single-ion magnet

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yan-Cong; Liu, Jun-Liang; Chen, Xiao-Ming; Tong, Ming-Liang [Key Lab. of Bioinorganic and Synthetic Chemistry of Ministry of Education, School of Chemistry, Sun Yat-Sen Univ., Guangzhou (China); Wernsdorfer, Wolfgang [Institut Neel, CNRS and Universite Joseph Fournier, Grenoble (France); Institute of Nanotechnology, Karlsruhe Institute of Technology (Germany); Physikalisches Institut, Karlsruhe Institute of Technology (Germany); Liu, Dan; Chibotaru, Liviu F. [Theory of Nanomaterials Group and INPAC-Institute of Nanoscale Physics and Chemistry, Katholieke Universiteit Leuven (Belgium)

    2017-04-24

    An extremely rare non-Kramers holmium(III) single-ion magnet (SIM) is reported to be stabilized in the pentagonal-bipyramidal geometry by a phosphine oxide with a high energy barrier of 237(4) cm{sup -1}. The suppression of the quantum tunneling of magnetization (QTM) at zero field and the hyperfine structures originating from field-induced QTMs can be observed even from the field-dependent alternating-current magnetic susceptibility in addition to single-crystal hysteresis loops. These dramatic dynamics were attributed to the combination of the favorable crystal-field environment and the hyperfine interactions arising from {sup 165}Ho (I=7/2) with a natural abundance of 100 %. (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Noncontact ultrasound imaging applied to cortical bone phantoms.

    Science.gov (United States)

    Bulman, J B; Ganezer, K S; Halcrow, P W; Neeson, Ian

    2012-06-01

    The purpose of this paper was to take the first steps toward applying noncontact ultrasound (NCU) to the tasks of monitoring osteoporosis and quantitative ultrasound imaging (QUS) of cortical bone. The authors also focused on the advantages of NCU, such as its lack of reliance on a technologist to apply transducers and a layer of acoustical coupling gel, the ability of the transducers to operate autonomously as specified by preprogrammed software, and the likely reduction in statistical and systematic errors associated with the variability in the pressure applied by the clinician to the transmitting transducer that NCU might provide. The authors also undertook this study in order to find additional applications of NCU beyond its past limited usage in assessing the severity of third degree burns. A noncontact ultrasound imaging system using a pair of specially designed broadband, 1.5 MHz noncontact piezoelectric transducers and cortical bone phantoms, were used to determine bone mineral density (BMD), speed of sound (SOS), integrated response (IR), and ultrasonic transmittance. Air gaps of greater than 3 cm, two transmission and two reflection paths, and a digital signal processor were also used in the collection of data from phantoms of nominal mass densities that varied from 1.17 to 2.25 g/cm(3) and in bone mineral density from 0 to 1.7 g/cm(3). Good correlations between known BMD and measured SOS, IR, and transmittance were obtained for all 17 phantoms, and methods for quantifying and minimizing sources of systematic errors were outlined. The BMD of the phantom sets extended through most of the in vivo range found in cortical bone. A total of 16-20 repeated measurements of the SOS, thickness, and IR for the phantom set that were conducted over a period of several months showed a small variation in the range of measurements of ±1%-2%. These NCU data were shown to be in agreement with similar results using contact ultrasound to be within 1%-2%. Transmittance

  9. Performance of the PT100 noncontact tonometer in healthy eyes

    Directory of Open Access Journals (Sweden)

    AlMubrad T

    2011-05-01

    Full Text Available Turki M AlMubradCornea Research Chair, Department of Optometry, College of Applied Medical Sciences, King Saud University, Riyadh, Kingdom of Saudi ArabiaBackground: The purpose of this study was to assess the repeatability and reproducibility of the PT100 noncontact tonometer and to compare its consistency with the Goldmann applanation tonometer (GAT in measuring intraocular pressure (IOP.Methods: Triplicate IOP measurements were obtained on two separate occasions using the PT100 and GAT from randomly selected eyes in 66 healthy volunteers aged 22 ± 1 years. The repeatability and reproducibility of each techniques was assessed. Agreement between the techniques was statistically quantified using intrasession repeatability for each technique as the basis for comparison.Results: Both techniques returned equal IOP values in the first measurement session (15 ± 3 mmHg. The second session showed a mean difference in average IOP (1 ± 0.71. The 95% limits of agreement between the techniques were –5.2 to 5.5 mmHg and –4.0 to 4.7 mmHg (sessions 1 and 2, respectively. These mean differences were not statistically significant (P > 0.05, paired t-test, with the PT100 underestimating IOP measurement by 1.00 mmHg. The mean intrasession IOP for GAT sessions 1 and 2 was 0 ± 0.90 mmHg and 0.04 ± 1.06 mmHg, respectively, and the corresponding mean IOP measurement difference for the PT100 was –0.06 ± 0.96 and –0.39 ± 0.94 mmHg (sessions 1 and 2, respectively; P > 0.05, paired t-test. Repeatability coefficients for the GAT IOP measurements were 1.8 mmHg and 2.1 mmHg for sessions 1 and 2, while the PT100 repeatability coefficient was 1.9 mmHg and 1.8 mmHg for sessions 1 and 2, respectively. The intrasession repeatability coefficient of both techniques for test–retest differences were within ±5 mmHg.Conclusion: The PT100 noncontact tonometer produced greater repeatability than the GAT in assessment of IOP, whereas GAT resulted in more reproducible

  10. Laser reduction of specific microorganisms in the periodontal pocket using Er:YAG and Nd:YAG lasers: a randomized controlled clinical study.

    Science.gov (United States)

    Grzech-Leśniak, K; Sculean, A; Gašpirc, Boris

    2018-05-15

    The objective of this study was to evaluate the microbiological and clinical outcomes following nonsurgical treatment by either scaling and root planing, combination of Nd:YAG and Er:YAG lasers, or by Er:YAG laser treatment alone. The study involved 60 patients with generalized chronic periodontitis, randomly assigned into one of three treatment groups of 20 patients. The first group received scaling and root planing by hand instruments (SRP group), the second group received Er:YAG laser treatment alone (Er group), and the third group received combined treatment with Nd:YAG and Er:YAG lasers (NdErNd group). Microbiological samples, taken from the periodontal pockets at baseline and 6 months after treatments, were assessed with PET Plus tests. The combined NdErNd laser (93.0%), followed closely by Er:YAG laser (84.9%), treatment resulted in the highest reduction of all bacteria count after 6 months, whereas SRP (46.2%) failed to reduce Treponema denticola, Peptostreptococcus micros, and Capnocytophaga gingivalis. Full-mouth plaque and bleeding on probing scores dropped after 6 months and were the lowest in both laser groups. The combination of NdErNd resulted in higher probing pocket depth reduction and gain of clinical attachment level (1.99 ± 0.23 mm) compared to SRP (0.86 ± 0.13 mm) or Er:YAG laser alone (0.93 ± 0.20 mm) in 4-6 mm-deep pockets. Within their limits, the present results provide support for the combination of Nd:YAG and Er:YAG lasers to additionally improve the microbiological and clinical outcomes of nonsurgical periodontal therapy in patients with moderate to severe chronic periodontitis.

  11. Gamma-ray relative energy response of Ce: YAG crystal

    International Nuclear Information System (INIS)

    Zhang Jianhua; Zhang Chuanfei; Hu Mengchun; Peng Taiping; Wang Zhentong; Tang Dengpan; Zhao Guangjun

    2010-01-01

    Gamma-ray relative energy response of Ce: YAG crystal, which is important for pulsed γ-ray measurement, was studied in this work.The Ce: YAG crystal, which was developed at Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, was aligned point by point with γ-rays scattered from an industrial 60 Co line source. The γ-ray relative energy response was calculated using the mass attenuation coefficient. The results show that the numerical calculation method of γ-ray relative energy response is reliable, and the experimental method with multi-energy point γ-ray by Compton scattering is also feasible, that can be used for checking up correctness of the numerical calculation results. (authors)

  12. Cutting of nonmetallic materials using Nd:YAG laser beam

    Institute of Scientific and Technical Information of China (English)

    Bashir Ahmed Tahir; Rashid Ahmed; M. G. B. Ashiq; Afaq Ahmed; M. A. Saeed

    2012-01-01

    This study deals with Nd:YAG laser cutting nonmetallic materials,which is one of the most important and popular industrial applications of laser.The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed.For approximate cutting depth,a theoretical study is conducted in terms of material property and cutting speed.Results show a nonlinear relation between the cutting depth and input energy.There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s.An extra energy is utilized in the deep cutting.It is inferred that as the laser power increases,cutting depth increases.The experimental outcomes are in good agreement with theoretical results.This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting,scribing,trimming,engraving,and marking nonmetallic materials.

  13. Photo-switch of pulsed Nd:YAG laser

    International Nuclear Information System (INIS)

    Ketta, W.W.J.

    1989-01-01

    In this work passive Q-switching and its effect on the output laser beam from a pulsed Nd:YAG laser was studied. This was achieved using the photochemically stable (BDNI) dye after dissolving it in dichloroethane. The absorption spectra of the dye solution and how suitable to use with Nd:YAG laser was also dealt with. Cooling unit for the laser system, a detector to detect the output pulse, and an electronic counter to measure the pulse duration were constructed. In the free-running regime, the divergence angle was measured. The form of the output, its energy, and how it is affected by the pumping energy were also studied. In the Q-switching regime, the relation between output and pumping energies was studied and compared to the same relation under the free-running regime. 5 tabs.; 33 figs.; 57 refs

  14. Pulsed Tm:YAG laser ablation of knee joint tissues

    Science.gov (United States)

    Shi, Wei-Qiang; Vari, Sandor G.; Duffy, J. T.; Miller, J. M.; Weiss, Andrew B.; Fishbein, Michael C.; Grundfest, Warren S.

    1992-06-01

    We investigated the effect of a free-running 2.01 micron pulsed Tm:YAG laser on bovine knee joint tissues. Ablation rates of fresh fibrocartilage, hyaline cartilage, and bone were measured in saline as a function of laser fluence (160 - 640 J/cm2) and fiber core size (400 and 600 microns). All tissues could be effectively ablated and the ablation rate increased linearly with the increasing fluence. Use of fibers of different core sizes, while maintaining constant energy fluence, did not result in significant difference in ablation rate. Histology analyses of the ablated tissue samples reveal average Tm:YAG radiation induced thermal damage (denatunalization) zones ranging between 130 and 540 microns, depending on the laser parameters and the tissue type.

  15. Tunable eye-safe Er:YAG laser

    International Nuclear Information System (INIS)

    Němec, M; Šulc, J; Indra, L; Fibrich, M; Jelínková, H

    2015-01-01

    Er:YAG crystal was investigated as the gain medium in a diode (1452 nm) pumped tunable laser. The tunability was reached in an eye-safe region by an intracavity birefringent filter. The four tuning bands were obtained peaking at wavelengths 1616, 1632, 1645, and 1656 nm. The broadest continuous tunability was 6 nm wide peaking at 1616 nm. The laser was operating in a pulsed regime (10 ms pulse length, 10 Hz repetition rate). The maximum mean output power was 26.5 mW at 1645 nm. The constructed system demonstrated the tunability of a resonantly diode-pumped Er:YAG laser which could be useful in the development of compact diode-pumped lasers for spectroscopic applications. (paper)

  16. Cutting of nonmetallic materials using Nd:YAG laser beam

    International Nuclear Information System (INIS)

    Tahir, Bashir Ahmed; Ashiq, M.G. B.; Saeed, M.A.; Ahmed, Rashid; Ahmed, Afaq

    2012-01-01

    This study deals with Nd:YAG laser cutting nonmetallic materials, which is one of the most important and popular industrial applications of laser. The main theme is to evaluate the effects of Nd:YAG laser beam power besides work piece scanning speed. For approximate cutting depth, a theoretical study is conducted in terms of material property and cutting speed. Results show a nonlinear relation between the cutting depth and input energy. There is no significant effect of speed on cutting depth with the speed being larger than 30 mm/s. An extra energy is utilized in the deep cutting. It is inferred that as the laser power increases, cutting depth increases. The experimental outcomes are in good agreement with theoretical results. This analysis will provide a guideline for laser-based industry to select a suitable laser for cutting, scribing, trimming, engraving, and marking nonmetallic materials. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  17. Effects of Er:YAG laser irradiation on human cartilage

    Science.gov (United States)

    Glinkowski, Wojciech; Brzozowska, Malgorzata; Ciszek, Bogdan; Rowinski, Jan; Strek, Wieslaw

    1996-03-01

    Irradiation of the hyaline or fibrous cartilage excised from the body of a human cadaver with Er:YAG laser beam, single pulse with a dose of 1 J, produces a crater with a depth of approximately 500 micrometers and a diameter varying from 5 to 300 micrometers. Histological examination has revealed that the laser-made craters were surrounded by a thin rim (2-10 micrometer) of charred and coagulated tissue. No damage was observed in the cartilage surrounding the rim. The presence of sharp demarcation between the tissue areas ablated by laser energy and the undamaged areas argues for the potential usefulness of the Er:YAG laser in surgery of cartilages.

  18. Nd:YAG laser in caries prevention: a clinical study

    International Nuclear Information System (INIS)

    Boari, Heloisa Gomes Dimiranda

    2000-01-01

    The caries prevention by using laser irradiation has been investigated during the last 30 years. The Nd: YAG laser associated with acidulated phosphate fluoride has been shown as a very promising technique for enamel caries prevention. The aim of this work was to clinically evaluate the efficiency of Nd: YAG laser associated with acidulated phosphate fluoride in pit and fissure caries prevention of children and adolescents. In this work it was determined the dye that enhance the effect of Nd: YAG laser in enamel. It was selected 242 pre-molar and molar teeth from 33 children and adolescents, aged from 7 to 15 years old. The selected teeth were free from caries or decalcification marks (active white marks) to the clinical and radiographic exams. The teeth were divided into two groups: the first group was laser irradiated and their homologous remained as a control. The right side teeth were dye-assisted Nd:YAG laser irradiated. The dye solution was a moisture of dust coal and equal parts of water and alcohol. The irradiation conditions were 60 mJ/10 Hz, optical fiber in contact mode, with diameter of 300 μm, resulting in an energy density of 84,9 J/cm 2 . The oclusal surface of the teeth was completely irradiated, specially on the slopes and in the deepest part of the pits and fissures. This procedure was repeated three times. In the sequence it was applied the acidulated phosphate fluoride for 4 minutes. On the left side teeth - control group- only acidulated phosphate fluoride was applied for the same time. The final examination considered the presence of caries and active white marks after a period of one year. There were statistical significant differences (p < 0.01) between the lased + fluoride group and the non irradiated group. The present study concluded that the technique used in this work can be an alternative clinical method for caries prevention. (author)

  19. Luminescence properties and energy transfer processes in YAG:Yb,Er single crystalline films

    International Nuclear Information System (INIS)

    Zorenko, Yu.; Gorbenko, V.; Savchyn, V.; Batentschuk, M.; Osvet, A.; Brabec, C.

    2013-01-01

    The paper is dedicated to the study of the optical properties of YAG:Yb,Er single-crystalline films (SCF) grown by liquid phase epitaxy. The absorption, cathodoluminescence and time-resolved photoluminescence spectra and photoluminescence decay curves were measured for the SCFs with different doping levels of Er 3+ (from 0.6 to 4.2 at.%) and Yb 3+ (from 0.1 to 0.6 at.%). The spectra, excited by synchrotron radiation in the fundamental absorption range of the YAG and in the intraionic absorption bands of both dopants, reveal energy transfer from the YAG host to the Er 3+ and Yb 3+ ions and between these ions. -- Highlights: •Growth of YAG:Yb,Er single crystalline films by LPE method. •Peculiarities of luminescence of YAG:Yb,Er films with different Er–Yb content. •Yb–Er energy transfer processes in YAG hosts

  20. Modular Architecture of a Non-Contact Pinch Actuation Micropump

    Directory of Open Access Journals (Sweden)

    Ruzairi Abdul Rahim

    2012-09-01

    Full Text Available This paper demonstrates a modular architecture of a non-contact actuation micropump setup. Rapid hot embossing prototyping was employed in micropump fabrication by using printed circuit board (PCB as a mold material in polymer casting. Actuator-membrane gap separation was studied, with experimental investigation of three separation distances: 2.0 mm, 2.5 mm and 3.5 mm. To enhance the micropump performance, interaction surface area between plunger and membrane was modeled via finite element analysis (FEA. The micropump was evaluated against two frequency ranges, which comprised a low driving frequency range (0–5 Hz, with 0.5 Hz step increments and a nominal frequency range (0–80 Hz, with 10 Hz per step increments. The low range frequency features a linear relationship of flow rate with the operating frequency function, while two magnitude peaks were captured in the flow rate and back pressure characteristic in the nominal frequency range. Repeatability and reliability tests conducted suggest the pump performed at a maximum flow rate of 5.78 mL/min at 65 Hz and a backpressure of 1.35 kPa at 60 Hz.

  1. Some image artefacts in non-contact mode force microscopy

    International Nuclear Information System (INIS)

    Dinte, B.P.; Watson, G.S.; Dobson, J.F.; Myhra, S.

    1996-01-01

    Full text: Non-contact mode Atomic Force Microscopy (AFM), performed in air, of two-dimensional hexagonal close-packed (2DHCP) layers of 200 nm diameter polystyrene spheres yields images containing artefacts ('ghost spheres') at layer edges and vacancy sites. The origin of these artefacts is clearly not the simple convolution of the tip and sample geometries, but must be the interaction between them. A computer program was written to simulate the experimental contours, assuming that the only force between the tip and the sample is the van der Waals (dispersion) force, and that the contours traced by the AFM tip are those of constant force derivative. The energy was calculated by integrating R -6 over the volumes of the tip and the sample, with a (constant) arbitrary scaling factor. The experimental contours were reproduced by the simulations, except for the 'ghost' artefacts. The assumption that there is only a dispersion force is thus incorrect. The experiments were performed in air, so that all surfaces were coated by a layer of adsorbed moisture. It is proposed that meniscus forces may be the origin of the artefacts

  2. Non-contact tensile viscoelastic characterization of microscale biological materials

    Science.gov (United States)

    Li, Yuhui; Hong, Yuan; Xu, Guang-Kui; Liu, Shaobao; Shi, Qiang; Tang, Deding; Yang, Hui; Genin, Guy M.; Lu, Tian Jian; Xu, Feng

    2018-06-01

    Many structures and materials in nature and physiology have important "meso-scale" structures at the micron length-scale whose tensile responses have proven difficult to characterize mechanically. Although techniques such as atomic force microscopy and micro- and nano-identation are mature for compression and indentation testing at the nano-scale, and standard uniaxial and shear rheometry techniques exist for the macroscale, few techniques are applicable for tensile-testing at the micrometre-scale, leaving a gap in our understanding of hierarchical biomaterials. Here, we present a novel magnetic mechanical testing (MMT) system that enables viscoelastic tensile testing at this critical length scale. The MMT system applies non-contact loading, avoiding gripping and surface interaction effects. We demonstrate application of the MMT system to the first analyses of the pure tensile responses of several native and engineered tissue systems at the mesoscale, showing the broad potential of the system for exploring micro- and meso-scale analysis of structured and hierarchical biological systems.

  3. Non-contact wearable single forearm cardiac biopotential acquisition device

    International Nuclear Information System (INIS)

    Gonçalves, Sérgio; Martins, Raul Carneiro

    2013-01-01

    In this work the authors propose a novel approach to obtain the electrocardiogram in the forearm using non-contact sensing. This new solution should be at same time portable, ergonomic and robust, enabling its use in different set of applications. A system of four electrodes was used in an adjustable sleeve to be wrapped in the forearm. No additional electrode references were used in other body parts. In order to increase the sensitivity of the system, an harmonium like approach was used in the design of the electrodes. The prototype was then compared with a similar system with a flat conformation. The developed prototype enabled the acquisition of an ECG signal in the forearm and the inclusion of the harmonium like electrode conformation resulted in a considerable increase of the sensitivity of the system. The acquired signal did not enable the identification of all characteristic cardiac waves. However, it was possible to identify clearly a signal pattern, characteristic of the QRS complex. The properties of the acquired signal restrict their use in rigorous electrocardiographic studies, allowing, however, its application in heart rate variability monitoring and biometric identification without the disadvantages usually associated with conventional electrodes. This makes it specially useful for man-machine interfaces and automated identification

  4. Analysis of a non-contact magnetoelastic torque transducer

    International Nuclear Information System (INIS)

    Andreescu, R.; Spellman, B.; Furlani, E.P.

    2008-01-01

    Results are presented for the performance of a magnetoelastic torque transducer that converts a torque-induced strain in a non-magnetic shaft into changes in a measurable magnetic field. The magnetic field is generated by a thin magnetostrictive layer that is coated onto the circumference of the shaft. The layer is magnetized and has an initial residual strain. The magnetization within the layer rotates in response to changes in the strain which occur when the shaft is torqued. The magnetic field produced by the layer changes with the magnetization and this can be sensed by a magnetometer to monitor the torque on the shaft. In this paper, a phenomenological theory is developed for predicting the performance of the transducer. The theory can be used to predict the magnetic field distribution of the transducer as a function of the physical properties of the magnetic coating, its residual strain, and the applied torque. It enables rapid parametric analysis of transducer performance, which is useful for the development and optimization of novel non-contact torque sensors

  5. Evaluation of the Keeler Pulsair non-contact tonometer.

    Science.gov (United States)

    Sponsel, W E; Kaufman, P L; Strinden, T I; DePaul, K L; Bowes, H N; Olander, K W; Barnebey, H S

    1989-10-01

    The recently-introduced Pulsair non-contact tonometer (Keeler Instruments, Inc, Broomall, PA) was evaluated against the Goldmann applanation tonometer in cannulated post mortem human eyes, and in living subjects at three clinical centers. Statistical analysis of the findings revealed strong linear relationships between Goldmann or manometric and Pulsair intraocular pressure readings, with correlation coefficients ranging from 0.79 to 0.97. However, with the Pulsair reading as the dependent variable, the slope of the relationship in each case was significantly less than 1.0 (range 0.65 to 0.83), while the intercept was positive (range 1.31 to 2.33 mmHg). Thus, the Pulsair tended to read low at intraocular pressure above the normal range. Conversion factors and a calibration table allowing intraocular pressure estimates more comparable to Goldmann tonometry using the current (J-series) Pulsair are provided herein. A calibration algorithm could be integrated into the circuitry of future production models of the Pulsair instrument.

  6. Clinical evaluation of the Non-Contact Tonometer Mark II.

    Science.gov (United States)

    Chauhan, B C; Henson, D B

    1988-09-01

    The purpose of this investigation was to test the reliability of the American Optical Non-Contact Tonometer Mark II (NCT II) using the Goldmann Applanation Tonometer (GAT) as the validating instrument. The sample contained 102 consecutive patients from our University Eye Clinic, of whom one-half had 4 NCT II measurements first, followed by 4 GAT measurements; the other one-half had 4 GAT measurements first, followed by 4 NCT II measurements. No significant change in intraocular pressure (IOP) was noted over the measurement sequence with either instrument. There was no significant difference between paired NCT II and GAT readings when the NCT II was used first; however, a highly significant difference between paired readings was obtained when the GAT was used first, indicating that the GAT measurement produced a delayed reduction in the IOP. This effect did not occur with the NCT II. Although the NCT II is shown to have a good overall reliability when compared to the GAT in both protocols, the agreement between any two tonometers may be influenced greatly by the very process of taking a measurement and by the dynamic nature of the IOP.

  7. A Novel Noncontact Ultrasonic Levitating Bearing Excited by Piezoelectric Ceramics

    Directory of Open Access Journals (Sweden)

    He Li

    2016-10-01

    Full Text Available A novel ultrasonic levitating bearing excited by three piezoelectric transducers is presented in this work. The transducers are circumferentially equispaced in a housing, with their center lines going through the rotation center of a spindle. This noncontact bearing has the ability to self-align and carry radical and axial loads simultaneously. A finite element model of the bearing is built in ANSYS, and modal analysis and harmonious response analysis are conducted to investigate its characteristics and driving parameters. Based on nonlinear acoustic theory and a thermodynamic theory of ideal gas, the radical and lateral load-carrying models are built to predict the bearing’s carrying capacity. In order to validate the bearing’s levitation force, a test system is established and levitating experiments are conducted. The experimental data match well with the theoretical results. The experiments reveal that the maximum radical and axial levitating loads of the proposed bearing are about 15 N and 6 N, respectively, when the piezoelectric transducers operate at a working frequency of 16.11 kHz and a voltage of 150 Vp-p.

  8. Non-Contact Measurements of Creep Properties of Refractory Materials

    Science.gov (United States)

    Lee, Jonghyun; Bradshaw, Richard C.; Hyers, Robert W.; Rogers, Jan R.; Rathz, Thomas J.; Wall, James J.; Choo, Hahn; Liaw, Peter

    2006-01-01

    State-of-the-art technologies for hypersonic aircraft, nuclear electric/thermal propulsion for spacecraft, and more efficient jet engines are driving ever more demanding needs for high-temperature (>2000 C) materials. At such high temperatures, creep rises as one of the most important design factors to be considered. Since conventional measurement techniques for creep resistance are limited to about 17OO0C, a new technique is in demand for higher temperatures. This paper presents a non-contact method using electrostatic levitation (ESL) which is applicable to both metallic and non-metallic materials. The samples were rotated quickly enough to cause creep deformation by centrifugal acceleration. The deformation of the samples was captured with a high speed camera and then the images were analyzed to estimate creep resistance. Finite element analyses were performed and compared to the experiments to verify the new method. Results are presented for niobium and tungsten, representative refractory materials at 2300 C and 2700 C respectively.

  9. Advances in Non-contact Measurement of Creep Properties

    Science.gov (United States)

    Hyers, Robert W.; Canepari, Stacy; Rogers, Jan. R.

    2009-01-01

    Our team has developed a novel approach to measuring creep at extremely high temperatures using electrostatic levitation (ESL). This method has been demonstrated on niobium up to 2300 C, while ESL has melted tungsten (3400 C). High-precision machined spheres of the sample are levitated in the NASA MSFC ESL, a national user facility, and heated with a laser. The laser is aligned off-center so that the absorbed photons transfer their momentum to the sample, causing it to rotate at up to 250,000+ RPM. The rapid rotation loads the sample through centripetal acceleration, causing it to deform. The deformation of the sample is captured on high-speed video, which is analyzed by machine-vision software from the University of Massachusetts. The deformations are compared to finite element models to determine the constitutive constants in the creep relation. Furthermore, the noncontact method exploits stress gradients within the sample to determine the stress exponent in a single test. This method was validated in collaboration with the University of Tennessee for niobium at 1985 C, with agreement within the uncertainty of the conventional measurements. A similar method is being employed on Ultra-High-Temperature ZrB2- SiC composites, which may see application in rocket nozzles and sharp leading edges for hypersonic vehicles.

  10. A Vision-Based Sensor for Noncontact Structural Displacement Measurement

    Science.gov (United States)

    Feng, Dongming; Feng, Maria Q.; Ozer, Ekin; Fukuda, Yoshio

    2015-01-01

    Conventional displacement sensors have limitations in practical applications. This paper develops a vision sensor system for remote measurement of structural displacements. An advanced template matching algorithm, referred to as the upsampled cross correlation, is adopted and further developed into a software package for real-time displacement extraction from video images. By simply adjusting the upsampling factor, better subpixel resolution can be easily achieved to improve the measurement accuracy. The performance of the vision sensor is first evaluated through a laboratory shaking table test of a frame structure, in which the displacements at all the floors are measured by using one camera to track either high-contrast artificial targets or low-contrast natural targets on the structural surface such as bolts and nuts. Satisfactory agreements are observed between the displacements measured by the single camera and those measured by high-performance laser displacement sensors. Then field tests are carried out on a railway bridge and a pedestrian bridge, through which the accuracy of the vision sensor in both time and frequency domains is further confirmed in realistic field environments. Significant advantages of the noncontact vision sensor include its low cost, ease of operation, and flexibility to extract structural displacement at any point from a single measurement. PMID:26184197

  11. Noncontact Sleep Study by Multi-Modal Sensor Fusion

    Directory of Open Access Journals (Sweden)

    Ku-young Chung

    2017-07-01

    Full Text Available Polysomnography (PSG is considered as the gold standard for determining sleep stages, but due to the obtrusiveness of its sensor attachments, sleep stage classification algorithms using noninvasive sensors have been developed throughout the years. However, the previous studies have not yet been proven reliable. In addition, most of the products are designed for healthy customers rather than for patients with sleep disorder. We present a novel approach to classify sleep stages via low cost and noncontact multi-modal sensor fusion, which extracts sleep-related vital signals from radar signals and a sound-based context-awareness technique. This work is uniquely designed based on the PSG data of sleep disorder patients, which were received and certified by professionals at Hanyang University Hospital. The proposed algorithm further incorporates medical/statistical knowledge to determine personal-adjusted thresholds and devise post-processing. The efficiency of the proposed algorithm is highlighted by contrasting sleep stage classification performance between single sensor and sensor-fusion algorithms. To validate the possibility of commercializing this work, the classification results of this algorithm were compared with the commercialized sleep monitoring device, ResMed S+. The proposed algorithm was investigated with random patients following PSG examination, and results show a promising novel approach for determining sleep stages in a low cost and unobtrusive manner.

  12. An imaging colorimeter for noncontact tissue color mapping.

    Science.gov (United States)

    Balas, C

    1997-06-01

    There has been a considerable effort in several medical fields, for objective color analysis and characterization of biological tissues. Conventional colorimeters have proved inadequate for this purpose, since they do not provide spatial color information and because the measuring procedure randomly affects the color of the tissue. In this paper an imaging colorimeter is presented, where the nonimaging optical photodetector of colorimeters is replaced with the charge-coupled device (CCD) sensor of a color video camera, enabling the independent capturing of the color information for any spatial point within its field-of-view. Combining imaging and colorimetry methods, the acquired image is calibrated and corrected, under several ambient light conditions, providing noncontact reproducible color measurements and mapping, free of the errors and the limitations present in conventional colorimeters. This system was used for monitoring of blood supply changes of psoriatic plaques, that have undergone Psoralens and ultraviolet-A radiation (PUVA) therapy, where reproducible and reliable measurements were demonstrated. These features highlight the potential of the imaging colorimeters as clinical and research tools for the standardization of clinical diagnosis and for the objective evaluation of treatment effectiveness.

  13. Heat effect of pulsed Er:YAG laser radiation

    Science.gov (United States)

    Hibst, Raimund; Keller, Ulrich

    1990-06-01

    Pulsed Er:YAG laser radiation has been found to be effective for dental enamel and dentin removal. Damage to the surrounding hard tissue is little, but before testing the Er:YAG laser clinically for the preparation of cavities, possible effects on the soft tissue of the pulp must be known. In order to estimate pulp damage , temperature rise in dentin caused by the laser radiation was measured by a thermocouple. Additionally, temperature distributions were observed by means of a thermal imaging system. The heat effect of a single Er:YAG laser pulse is little and limited to the vicinity of the impact side. Because heat energy is added with each additional pulse , the temperature distribution depends not only on the radiant energy, but also on the number of pulses and the repetition rate. Both irradiation conditions can be found , making irreversible pulp damage either likely or unlikely. The experimental observations can be explained qualitatively by a simple model of the ablation process.

  14. Bactericidal effect of Nd:YAG laser irradiation in endodontics

    Science.gov (United States)

    Aun, Carlos E.; Barberini, Alexandre F.; Camargo, Selma C. C.; Silva Kfouri, Luciana; Lorenzetti Simionato, Maria R.

    1999-05-01

    The success of endodontic therapy is based on the elimination of bacterial colonization from the endodontic system and periapical tissues. Recent studies have been showing the bactericidal effect of laser in root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canal treatment. The propose of the study is to evaluate the effect of Nd:YAG laser irradiation in contaminated root canals from upper central incisor. For the experiment 12 teeth were selected, respect at the apical third, sterilized, and 10 μm Streptococcus sanguis liquid culture were inoculated in the root canals. The laser test groups were irradiated with Nd:YAG laser at standard setting of 15Hz, 100mj and 1,5 W for 10, 20 and 30 seconds each in slow helicoidal movements from the apex to the top using a 300 micrometers fiber. After the procedure the specimens were placed in Tryptic Soy Agar, the number of colony forming units was evaluated. The experiment showed a significant reduction on viability of Streptococcus sanguis at the respective time of 20 and 30 seconds.

  15. Hyperfine structure investigation of the first excited state 4Isub(13/2) (5,418-1) in Holmium-165 by the atomic beam resonance method

    International Nuclear Information System (INIS)

    Aldenhoven, R.

    1976-01-01

    By the method of atomic beam resonance the hyperfine structure of the first excited state 4 Isub(13/2) (5418 cm -1 ) of 165 Holmium was studied for the first time. Using a suitable ΔF = 0 transition, the gsub(J)-factor was measured. After a determination of estimates for the hyperfine constants A and B from two suitably chosen ΔF = 0 transitions, the hyperfine splittings have been measured. (orig./WL) [de

  16. The effect and influence of lumen holmium laser lithotripsy on serum oxidative stress proteins and inflammatory factors of ureteral calculi patients

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    2016-09-01

    Full Text Available Objective: To investigate the effect and influence of lumen holmium laser lithotripsy on treating serum oxidative stress proteins and inflammatory factors of patients with ureteral calculi. Methods: A total of 120 cases of patients with ureteral calculi treated in our hospital from May 2010 to Nov 2014 were enrolled in this research for an analysis study. The effect and influence on serum oxidative stress proteins and inflammatory factors of lumen holmium laser lithotripsy on ureteral calculi patients were assayed. Then 120 cases of healthy subjects in our hospital at the same period were taken as control. Results: Among the 120 cases of ureteral calculi patients, 113 cases of patients showed successful operation, with a success rate of 94.2%. The average calculi-discharged time was (28.4 ± 11.2 d and the average operation time was (58.9 ± 10.7 min, while the postoperative hospital stay is (3.8 ± 1.2 d. The results also showed that the levels of NOX1. NOX3, NOX4 and NOX5, and levels of interleukin-2 (IL-2, IL-6, IL-10 and TNF-α of patients with ureteral calculi were significantly higher, compared with the control group, and these parameters were normalized greatly after operation with that the levels of them were significantly different from those before operation. Conclusion: Lumen holmium laser lithotripsy exerts a significant effect on ureteral calculi patients and the oxidative stress parameters and inflammatory factor were normalized greatly.

  17. Outcome analysis of holmium laser and pneumatic lithotripsy in the endoscopic management of lower ureteric calculus in pediatric patients: a prospective study

    Directory of Open Access Journals (Sweden)

    Ankur Jhanwar

    Full Text Available ABSTRACT Objective: To analyse outcomes of holmium laser and pneumatic lithotripsy in treatment of lower ureteric calculus in pediatric patients. Materials and methods: Prospective study conducted between August 2013 and July 2015. Inclusion criteria were lower ureteric calculus with stone size ≤1.5cms. Exclusion criteria were other than lower ureteric calculus, stone size ≥1.5cms, congenital renal anomalies, previous ureteral stone surgery. Patients were divided into two groups. Group A underwent pneumatic and group B underwent laser lithotripsy procedure. Patient's baseline demographic and peri-operative data were recorded and analysed. Post operatively X-ray/ultrasound KUB (Kidney, ureter and bladder was performed to assess stone free status. Results: A total of 76 patients who met the inclusion criteria to ureteroscopic intracorporeal lithotripsy were included. Group A and B included 38 patients in each. Mean age was 12.5±2.49 in Group A and 11.97±2.74 years in Group B respectively (p=0.38. Overall success rate was 94.73% in Group A and 100% in Group B, respectively (p=0.87. Conclusion: Holmium Laser lithotripsy is as efficacious as pneumatic lithotripsy and can be used safely for the endoscopic management of lower ureteric calculus in pediatric patients. However, holmium laser requires more expertise and it is a costly alternative.

  18. Effects of neodymium concentration on optical characteristics of polycrystalline Nd:YAG laser materials

    International Nuclear Information System (INIS)

    Ikesue, A.; Kamata, K.; Yoshida, K.

    1996-01-01

    A neodymium-doped yttrium-aluminum garnet (Y 3 Al 5 O 12 , YAG) (Nd:YAG) ceramic that contained 0.3--4.8 at.% neodymium additives and exhibited nearly the same optical properties as those of a single crystal was fabricated by a solid-state reaction method using high-purity powders. Although the integrated absorption intensity of the 2 H 9/2 + 4 F 5/2 bands simply increased as the neodymium concentration in the YAG ceramics decreased, the fluorescence intensity of the 2.4 at.% Nd:YAG ceramic was the strongest among Nd:YAG ceramics with various neodymium concentrations and a 0.9 at.% Nd:YAG single crystal. An oscillation experiment was performed on a continuous-wave (cw) laser with a diode-laser exciting system using those ceramics and the single crystal. The oscillation threshold and slope efficiency in that analysis were 309 mW and 28%, respectively, for the 1.1 at.% Nd:YAG ceramics and 356 mW and 40%, respectively, for the 2.4 at.% Nd:YAG ceramics. The lasing characteristics of the ceramics in the present work were superior to those of a 0.9 at.% Nd:YAG single crystal that was fabricated by the Czochralski (Cz) method

  19. Fabrication of Nd:YAG transparent ceramics with both TEOS and MgO additives

    International Nuclear Information System (INIS)

    Yang Hao; Qin Xianpeng; Zhang Jian; Wang Shiwei; Ma Jan; Wang Lixi; Zhang Qitu

    2011-01-01

    Research highlights: → It is well known that the use of TEOS as sintering aid is required to reach fully dense and transparent Nd:YAG ceramics. However, it is difficult to produce high quality transparent Nd:YAG ceramics only using TEOS as sintering aid. In this present work, high quality transparent Nd:YAG ceramic was fabricated using both TEOS and MgO as sintering aids. There have been few reports that both TEOS and MgO were co-added as sintering aids in YAG or Nd:YAG transparent ceramics to date. The transmittance of Nd:YAG ceramic is 83.8% at 1064 nm. The effect of MgO on the optical properties of transparent ceramics was also studied. - Abstract: Neodymium doped YAG transparent ceramics were fabricated by vacuum reactive sintering method using commercial α-Al 2 O 3 , Y 2 O 3 and Nd 2 O 3 powders as the starting materials with both tetraethyl orthosilicate (TEOS) and MgO as sintering aids. The morphologies and microstructure of the powders and Nd:YAG transparent ceramics were investigated. Fully dense Nd:YAG ceramics with average grain size of ∼10 μm were obtained by vacuum sintering at 1780 deg. C for 8 h. No pores and grain-boundary phases were observed. The in-line transmittance of the ceramic was 83.8% at 1064 nm.

  20. Gingival melanin depigmentation by Er:YAG laser: A literature review.

    Science.gov (United States)

    Pavlic, Verica; Brkic, Zlata; Marin, Sasa; Cicmil, Smiljka; Gojkov-Vukelic, Mirjana; Aoki, Akira

    2018-04-01

    Laser ablation is recently suggested as a most effective and reliable technique for depigmentation of melanin hyperpigmented gingiva. To date, different lasers have been used for gingival depigmentation (CO 2 , diode, Nd:YAG, Er:YAG and Er,Cr:YSGG lasers). The use of Er:YAG laser for depigmentation of melanin hyperpigmented gingiva has gained increasing importance in recent years. The purpose of this study was to report removal of gingival melanin pigmentation using an Er:YAG laser in a literature review. The main outcomes, such as improvement of signs (clinical parameters of bleeding, erythema, swelling and wound healing), symptoms (pain) and melanin recurrence/repigmentation were measured. The literature demonstrated that depigmentation of gingival melanin pigmentation can be performed safely and effectively by Er:YAG laser resulting in healing and an esthetically significant improvement of gingival discoloration. Thus, Er:YAG laser seems to be safe and useful in melanin depigmentation procedure. However, the main issue in giving the final conclusion of the optimal Er:YAG laser use in melanin depigmentation is that, to date, studies are offering completely discrepant Er:YAG laser procedure protocols (complex settings of laser parameters), and different criteria for the assessment of depigmentation and repigmentation (recurrence), thus hampering the comparison of the results. Therefore, further studies are necessary to give an optimal recommendation on the use of Er:YAG laser in gingival melanin hyperpigmentation.

  1. Perspectives of transurethral robotic laser resection of the prostate: vaporization and coagulation effects with the Nd:YAG laser

    Science.gov (United States)

    Ho, Gideon; Teo, Ming Y.; Kwoh, Chee K.; Ng, Wan S.; Cheng, Wai S.

    2000-05-01

    A longer operating time and steeper learning curve in mastering the techniques for transurethral laser resection of the prostate are the main problems faced by surgeons compared to standard transurethral resection of the prostate (TURP). However, these disadvantages can be solved with the introduction of a treatment modality designed and developed based on an integrated system of computer, robotics and laser technology. In vitro experiments were carried out to determine variables affecting the vaporization and coagulation lesions, in order to identify the parameters that could optimize this modality. Human cadaveric prostate and fresh chicken breast tissues were irradiated with different parameters using continuous wave Nd:YAG laser fiber in contact with the tissue. The effects of irrigant flowrate, fiber/tissue angle of inclination, number of passes, direction, speed and power of lase on the volume of tissue vaporized and coagulated, were assessed. A non-contact optical coordinate measuring machine was used to measure the depth and width of the vaporized and coagulated lesion. Results reveal that for each directional vaporization path (forward, clockwise and counter-clockwise), power and speed of lase are the most significant parameters influencing the volume of the vaporized and coagulated lesion. Optimized values of the power and speed of lase at 100 W and 1 - 3 mm/s respectively were obtained from the experiments when the tissues were irradiated in the forward, clockwise and counter-clockwise directions. It was concluded from our study to quantify tissue removal and damage, optimized values of irradiation power and speed could be obtained and implemented in the procedure of transurethral robotic laser resection of the prostate.

  2. Q-switched Nd:YAG/V:YAG microchip 1338 nm laser for laser-induced breakdown spectroscopy

    Science.gov (United States)

    Šulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

    2017-12-01

    Q-switched microchip laser emitting radiation at wavelength 1338nm was tested as a radiation source for laser induced breakdown spectroscopy (LIBS). This laser used sandwich crystal which combined in one piece the cooling part (undoped YAG crystal 4mm long), the active laser part (Nd:YAG crystal 12mm long), and the saturable absorber (V:YAG crystal 0.7mm long). The diameter of this crystal was 5 mm. The microchip resonator consisted of dielectric mirrors directly deposited on the monolith crystal surfaces. The pump mirror (HT @ 808 nm, HR @ 1.3 ¹m) was placed on the undoped YAG part. The output coupler (R = 90% @ 1338 nm) was placed on the V:YAG part. The fibre-coupled 808nm pumping laser diode was operating in pulsed regime (rep. rate 250 Hz, pulse width 300 ¹s, pulse energy 6 mJ). Using this pumping, stable and high reproducible Q-switched pulses were generated at wavelength 1338 nm. Pulse length was 6.2 ns (FWHM) and the mean output power was 33mW. The single pulse energy and peak power was 0.13mJ and 21kW, respectively. Laser was operating in fundamental TEM00 mode. The laser radiation was focused on a tested sample using single plano-convex lens (focal length 75 mm). The focal spot radius was 40 ¹m. The corresponding peak-power density was 0.83GW/cm2. The laser induced break-down was successfully reached and corresponding laser-induced plasma spectra were recorded for set of metallic elements (Cu, Ag, Au, In, Zn, Al, Fe, Ni, Cr) and alloys (Sn-Pb solder, duralumin, stainless-steel, brass). To record the spectra, StellarNet BLACK-Comet concave grating CCD-based spectrometer was used without any special collimation optics. Thanks to used laser wavelength far from the detector sensitivity, no special filtering was needed to overcome the CCD dazzling. The constructed laser could significantly improve repletion-rate of up-to-date LIBS devices.

  3. A noncontact laser system for measuring soil surface topography

    International Nuclear Information System (INIS)

    Huang, C.; White, I.; Thwaite, E.G.; Bendeli, A.

    1988-01-01

    Soil surface topography profoundly influences runoff hydrodynamics, soil erosion, and surface retention of water. Here we describe an optical noncontact system for measuring soil surface topography. Soil elevation is measured by projecting a laser beam onto the surface and detecting the position of the interception point. The optical axis of the detection system is oriented at a small angle to the incident beam. A low-power HeNe (Helium-Neon) laser is used as the laser source, a photodiode array is used as the laser image detector and an ordinary 35-mm single lens reflex camera provides the optical system to focus the laser image onto the diode array. A wide spectrum of measurement ranges (R) and resolutions are selectable, from 1 mm to 1 m. These are determined by the laser-camera distance and angle, the focal length of the lens, and the sensing length of the diode array and the number of elements (N) contained in the array. The resolution of the system is approximately R/2N. We show for the system used here that this resolution is approximately 0.2%. In the configuration selected, elevation changes of 0.16 mm could be detected over a surface elevation range of 87 mm. The sampling rate of the system is 1000 Hz, which permits soil surfaces to be measured at speeds of up to 1 m s −1 with measurements taken at 1-mm spacing. Measurements of individual raindrop impacts on the soil and of soil surfaces before and after rain show the versatility of the laser surface profiler, which has applications in studies of erosion processes, surface storage and soil trafficability

  4. Non-contact magnetic coupled power and data transferring system for an electric vehicle

    International Nuclear Information System (INIS)

    Matsuda, Y.; Sakamoto, H.

    2007-01-01

    We have developed a system which transmits electric power and communication data simultaneously in a non-contact method using a magnetic coupling coil. Already, we are developing the fundamental technology of a non-contact charging system, and this is applied in electric shavers, electric toothbrushes, etc. Moreover, basic experiments are being conducted for applying this non-contact charging system to electric equipments such as an electric vehicle (EV), which is a zero emission vehicle and environmentally excellent and will be the transportation means of the next generation. The technology can also be applied in other electronic equipment, etc. However, since the power supply route for these individual devices is independent, the supply system is complicated. EV also has to perform the transmission of electric power and the transmission of information (data), such as the amount of the charge, in a separate system, and thus is quite complicated. In this study, by performing simultaneously the transmission of electric power and information (data) using magnetic coupling technology in which it does not contact, the basic experiment aimed at attaining and making unification of a system simple was conducted, and the following good results were obtained: (1) Electric power required for load can be transmitted easily by non-contact. (2) A signal can easily be transmitted bidirectionally by non-contact. (3) This system is reliable, and is widely applicable

  5. Development of a high cycle vibration fatigue diagnostic system with non-contact vibration sensing

    International Nuclear Information System (INIS)

    Nekomoto, Yoshitsugu; Tanaka, Masanori; Nishimura, Moritatsu; Matsumoto, Kenji; O'shima, Eiji

    2004-01-01

    Nuclear power plants have a large number of pipes. These small-diameter pipe branches in particles are often damaged due to high-cycle fatigue. In order to ensure the reliability of a plant it is important to detect fatigue damages in pipe branches at an early stage and to develop the technology to predict and diagnose the advancement of fatigue. Further, in order to carry out the diagnosis of the piping system effectively during operation, non-contact evaluation is useful. Hence, we have developed a ''high-cycle fatigue diagnostic system with non-contact vibration sensing'', which measures the vibration of the pipe branch using a non-contact sensor. (author)

  6. Non-contact optoacoustic imaging with focused air-coupled transducers

    Energy Technology Data Exchange (ETDEWEB)

    Deán-Ben, X. Luís [Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg (Germany); Pang, Genny A.; Razansky, Daniel, E-mail: dr@tum.de [Institute for Biological and Medical Imaging (IBMI), Helmholtz Zentrum München, Neuherberg (Germany); School of Medicine, Technische Universität München (TUM), Munich (Germany); Montero de Espinosa, Francisco [CSIC, Institute of Physics and Communication Technologies, Madrid (Spain)

    2015-08-03

    Non-contact optoacoustic imaging employing raster-scanning of a spherically focused air-coupled ultrasound transducer is showcased herein. Optoacoustic excitation with laser fluence within the maximal permissible human exposure limits in the visible and near-infrared spectra is applied to objects with characteristic dimensions smaller than 1 mm and absorption properties representative of the whole blood at near-infrared wavelengths, and these signals are shown to be detectable without contact to the sample using an air-coupled transducer with reasonable signal averaging. Optoacoustic images of vessel-mimicking tubes embedded in an agar phantom captured with this non-contact sensing technique are also showcased. These initial results indicate that an air-coupled ultrasound detection approach can be suitable for non-contact biomedical imaging with optoacoustics.

  7. Development of a high cycle vibration fatigue diagnostic system with non-contact vibration sensing

    International Nuclear Information System (INIS)

    Yoshitsugu, Nekomoto; Satoshi, Kiriyama; Moritatsu, Nishimura; Kenji, Matsumoto; Eiji, O'shima

    2001-01-01

    Nuclear power plants have a large number of pipes. Of these small-diameter pipe branches in particular are often damaged due to high-cycle fatigue. In order to ensure the reliability of a plant it is important to detect the fatigues in pipe branches at an early stage and to develop the technology to predict and diagnose the advancement of fatigue. Further, in order to carry out the diagnosis of the piping system effectively during operation, non-contact evaluation is useful. Hence, we have developed a 'high-cycle fatigue diagnostic system with non-contact vibration sensing', where the vibration of the pipe branch is measured using a non-contact sensor. Since the contents of the developed sensor technology has already been reported, this paper mainly describes the newly developed high-cycle fatigue diagnostic system. (authors)

  8. The non-contact biometric identified bio signal measurement sensor and algorithms.

    Science.gov (United States)

    Kim, Chan-Il; Lee, Jong-Ha

    2018-04-25

    In these days, wearable devices have been developed for effectively measuring biological data. However, these devices have tissue allege and noise problem. To solve these problems, biometric measurement based on a non-contact method, such as face image sequencing is developed. This makes it possible to measure biometric data without any operation and side effects. However, it is impossible for a remote center to identify the person whose data are measured by the novel methods. In this paper, we propose the novel non-contact heart rate and blood pressure imaging system, Deep Health Eye. This system has authentication process at the same time as measuring bio signals, through non-contact method. In the future, this system can be convenient home bio signal monitoring system by combined with smart mirror.

  9. Short-Range Noncontact Sensors for Healthcare and Other Emerging Applications: A Review

    Directory of Open Access Journals (Sweden)

    Changzhan Gu

    2016-07-01

    Full Text Available Short-range noncontact sensors are capable of remotely detecting the precise movements of the subjects or wirelessly estimating the distance from the sensor to the subject. They find wide applications in our day lives such as noncontact vital sign detection of heart beat and respiration, sleep monitoring, occupancy sensing, and gesture sensing. In recent years, short-range noncontact sensors are attracting more and more efforts from both academia and industry due to their vast applications. Compared to other radar architectures such as pulse radar and frequency-modulated continuous-wave (FMCW radar, Doppler radar is gaining more popularity in terms of system integration and low-power operation. This paper reviews the recent technical advances in Doppler radars for healthcare applications, including system hardware improvement, digital signal processing, and chip integration. This paper also discusses the hybrid FMCW-interferometry radars and the emerging applications and the future trends.

  10. Transmission of Er:YAG laser through different dental ceramics.

    Science.gov (United States)

    Sari, Tugrul; Tuncel, Ilkin; Usumez, Aslihan; Gutknecht, Norbert

    2014-01-01

    The aim of this study was to determine the erbium-doped yttrium aluminum garnet (Er:YAG) laser transmission ratio through different dental ceramics with different thicknesses. Laser debonding procedure of adhesively luted all-ceramic restorations is based on the transmission of laser energy through the ceramic and the ablation of resin cement, because of the transmitted laser energy. Five different dental ceramics were evaluated in this study: sintered zirconium-oxide core ceramic, monolithic zirconium-oxide ceramic, feldspathic ceramic, leucite-reinforced glass ceramic, and lithium disilicate-reinforced glass ceramic. Two ceramic discs with different thicknesses (0.5 and 1 mm) were fabricated for each group. Ceramic discs were placed between the sensor membrane of the laser power meter and the tip of the contact handpiece of an Er:YAG laser device with the aid of a custom- made acrylic holder. The transmission ratio of Er:YAG laser energy (500 mJ, 2 Hz, 1 W, 1000 μs) through different ceramic discs was measured with the power meter. Ten measurements were made for each group and the results were analyzed with two way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) tests. The highest transmission ratio was determined for lithium disilicate-reinforced ceramic with 0.5 mm thickness (88%) and the lowest was determined for feldspathic ceramic with 1 mm thickness (44%). The differences among the different ceramics and between the different thicknesses were significant (pCeramic type and thickness should be taken into consideration to adjust the laser irradiation parameters during laser debonding of adhesively luted all-ceramic restorations.

  11. Emission sensitization processes involving Nd{sup 3+} in YAG

    Energy Technology Data Exchange (ETDEWEB)

    Lupei, V., E-mail: lupei_voicu@yahoo.com [National Institute of Laser, Plasma and Radiation Physics, Bucharest 077125 (Romania); Lupei, A.; Gheorghe, C. [National Institute of Laser, Plasma and Radiation Physics, Bucharest 077125 (Romania); Ikesue, A. [World Lab. Co., Nagoya (Japan)

    2016-02-15

    The paper investigates the characteristics of sensitization processes of Nd{sup 3+} emission in YAG ceramics under broad band pumping by co-doping with Cr{sup 3+} and the prospect of using Nd{sup 3+} and Cr{sup 3+} for sensitization of emission of Yb{sup 3+}. It is evidenced that the energy transfer from Cr{sup 3+} to Nd{sup 3+} involves both direct and weak migration-assisted processes and is thus dependent on the concentrations of both species. It is also found that the ion–ion interaction responsible for the direct transfer contains besides the dipole–dipole coupling strong superexchange contribution that dominates the transfer to the Nd{sup 3+} ions up to the third coordination sphere and has major implication in sensitization. Investigation of (Cr, Nd, Yb)-doped YAG ceramics shows that Cr{sup 3+} can sensitize the emission of Yb{sup 3+} both via the chain Cr–Nd–Yb or by direct Cr–Yb energy transfer. The prospect of utilization of these processes in the solar-pumped laser is discussed. - Highlights: • The efficiency of sensitization increases at high Cr and Nd doping concentrations. • The Cr-to-Nd energy transfer involves both direct and migration-assisted processes. • The direct transfer implies both dipole–dipole and superexchange interactions. • The superexchange interaction has major influence on sensitization. • Sensitized emission of Yb{sup 3+} in (Cr,Nd,Yb):YAG by Cr–Nd–Yb and Cr–Yb transfers.

  12. All solid-state diode pumped Nd:YAG MOPA with stimulated Brillouin phase conjugate mirror

    NARCIS (Netherlands)

    Offerhaus, Herman L.; Godfried, Herman; Godfried, H.P; Witteman, W.J.

    1996-01-01

    At the Nederlands Centrum voor Laser Research (NCLR) a 1 kHz diode-pumped Nd:YAG Master Oscillator Power Amplifier (MOPA) chain with a Stimulated Brillouin Scattering (SBS) Phase Conjugate mirror is designed and operated. A small Brewster angle Nd:YAG slab (2 by 2 by 20 mm) is side pumped with 200

  13. LASIK flap breakthrough in Nd:YAG laser treatment of epithelial ingrowth

    NARCIS (Netherlands)

    Lapid-Gortzak, Ruth; Hughes, John M.; Nieuwendaal, Carla P.; Mourits, Maarten P.; van der Meulen, Ivanka J. E.

    2015-01-01

    To present two cases with complications after Nd:YAG laser treatment of epithelial ingrowth. Case reports. Dense central recurrent epithelial ingrowth was treated with a Nd:YAG laser directed at the epithelial nests in the LASIK flap interface in one case. Misalignment of the aiming beam after

  14. Nd:YAG Lasers Treating of Carious Lesion and Root Canal In Vitro

    Directory of Open Access Journals (Sweden)

    Danqing Xia

    2012-01-01

    Full Text Available Dental caries is a transmissible bacterial disease process, with cavities at the end, and caused by acids from bacterial metabolism. The essence of dental treatment is to clean and disinfect bacterial contamination from the tooth. In this work, we tried to demonstrate the cleaning and disinfecting effects of Nd:YAG laser irradiation on dental carious lesion and root canal in vitro. Acousto-optic Q-switched quasicontinuous and Cr3+:YAG crystal Q-switched pulse Nd:YAG lasers were employed to treat caries lesion and the root canal, respectively. Results showed that acousto-optic Q-switched quasicontinuous Nd:YAG laser irradiation and Cr3+:YAG crystal Q-switched pulse Nd:YAG laser irradiation could rapidly clean decayed material and bacterial contamination from dental carious lesion and the narrow tail end of root canal with minimally invasive in vitro, respectively. It was concluded that acousto-optic Q-switched quasicontinuous laser irradiation may be a rapid and effective alternative caries treatment, and Cr3+:YAG crystal Q-switched pulse Nd:YAG laser irradiation may be an effective method for canal cleaning and disinfecting during root canal therapy.

  15. Successful treatment of acne keloidalis nuchae with erbium:YAG laser: a comparative study.

    Science.gov (United States)

    Gamil, Hend D; Khater, Elsayed M; Khattab, Fathia M; Khalil, Mona A

    2018-05-14

    Acne keloidalis nuchae (AKN) is a chronic inflammatory disease involving hair follicles of the neck. It is a form of keloidal scarring alopecia that is often refractory to medical or surgical management. To evaluate the efficacy of Er:YAG laser in the treatment of AKN as compared to long pulsed Nd:YAG laser. This study was conducted on 30 male patients with AKN. Their ages ranged from 19 to 47 years with a mean age of 36.87 ± 7.8 years. Patients were divided randomly into two groups of 15 patients, each receiving six sessions of either Er:YAG or long-pulsed Nd:YAG laser therapy. A statistically significant decrease in the number of papules was detected at the end of therapy in both groups, with a mean of 91.8% improvement in the Er:YAG group versus 88% in the Nd:YAG group. A significant decrease in plaques count was detected only in the Er: YAG group while a significant decrease in plaques size and consistency was recorded in both groups. The Er: YAG laser proved to be a potentially effective and safe modality both in the early and late AKN lesions.

  16. Shift and broadening of emission lines in Nd 3: YAG laser crystal ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 86; Issue 6. Shift and broadening of emission lines in Nd3+:YAG laser crystal influenced by input energy. POURMAND SEYED EBRAHIM REZAEI ... Keywords. Nd3+:YAG crystal; heat generation; three-level emission lines; four-level emission lines; input energy.

  17. Intrinsic risk factors of noncontact ankle sprains in soccer: a prospective study on 100 professional players.

    Science.gov (United States)

    Fousekis, Konstantinos; Tsepis, Elias; Vagenas, George

    2012-08-01

    Ankle sprain is an extremely common injury in soccer players. Despite extensive research, the intrinsic cause of this injury under noncontact conditions remains unclear. To identify intrinsic risk factors for noncontact ankle sprains in professional soccer players. Cohort study; Level of evidence, 2 One hundred professional soccer players were assessed in the preseason for potential risk factors of noncontact ankle sprains. The assessment included (A) ankle joint asymmetries (right-left) in isokinetic muscle strength, flexibility, proprioception, and stability; (B) somatometric asymmetries; (C) previous injuries; and (D) lateral dominance traits. Noncontact ankle sprains were prospectively recorded and diagnosed for a full competition period (10 months). Seventeen of the players sustained at least 1 noncontact ankle sprain. Logistic regression revealed that players with (A) eccentric isokinetic ankle flexion strength asymmetries (odds ratio [OR] = 8.88; 95% confidence interval [CI], 1.95-40.36, P = .005), (B) increased body mass index (OR = 8.16; 95% CI, 1.42-46.63, P = .018), and (C) increased body weight (OR = 5.72; 95% CI, 1.37-23.95, P = .017 ) each had a significantly higher risk of a noncontact ankle sprain. A trend for younger players (OR = 0.28; 95% CI, 0.061-1.24, P = .092) and for players with ankle laxity asymmetries (OR = 3.38; 95% CI, 0.82-14.00, P = .093) to be at greater risk for ankle sprain was also apparent to the limit of statistical significance (.05 ankle flexors and increased body mass index and body weight raise the propensity for ankle sprains in professional soccer players. Age and asymmetries in ankle laxity are potential factors worth revisiting, as there was an indication for younger players and players with ankle instability to be at higher risk for ankle injury. Proper preseason evaluation may improve prevention strategies for this type of injury in soccer.

  18. Effect of transscleral neodymium: YAG cyclophotocoagulation on intraocular lenses

    Energy Technology Data Exchange (ETDEWEB)

    Blomquist, P.H.; Gross, R.L.; Koch, D.D. (Baylor College of Medicine, Houston, TX (USA))

    1990-03-01

    A neodymium: YAG laser operating in the thermal mode was used to irradiate isolated intraocular lenses (IOLs) and to perform transscleral cyclophotocoagulation on pseudophakic autopsy eyes to investigate the potential damage to IOL haptics such irradiation may cause. In the isolated IOLs, 70 mJ of energy deformed and partially melted both polymethylmethacrylate (PMMA) and polypropylene haptics. One of the capsular-fixated PC-IOL haptics in an autopsy eye partially melted when irradiated with the maximum energy level (8.8 J), with the aiming beam focused 1 mm posterior to the limbus and maximal posterior focus offset.

  19. Palliation of oesophagogastric neoplasms with Nd:YAG laser treatment

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, S.; Fischerman, K. (Rigshospitalet, Copenhagen (Denmark))

    1990-01-01

    The palliative effect of endoscopic Nd:YAG laser treatment of malignant strictures of the oesophagus and cardia was prospectively evaluated in 30 patients. Most were primarily treated for dysphagia, and swallowing was improved in 21 and normalized in 14 of these patients. Two patients were successfully treated for bleeding. Six patients developed complications (including two perforations), and four of these were fatal. The median survival was four months. It is concluded that in a great number of patients with inoperable cancer of the oesophagus and cardia, laser treatment is better than other palliative procedures. 23 refs., 2 tabs.

  20. Cooperative emission in ion implanted Yb:YAG waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, G V; Desirena, H; De la Rosa, E [Centro de Investigaciones en Optica, Loma del Bosque 115, Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Flores-Romero, E; Rickards, J; Trejo-Luna, R [Instituto de Fisica, UNAM, Apartado Postal 20364, 01000 Mexico, D. F. (Mexico); Marquez, H, E-mail: gvvazquez@cio.mx [Departamento de Optica, CICESE, Km 107 Carr. Tijuana-Ensenada, 22860 Ensenada, B. C. (Mexico)

    2011-01-01

    In this work, we report the analysis of spectroscopic properties of waveguides fabricated by ion implantation in YAG doped with Yb{sup 3+} ions. Three emission bands were detected in the blue, green and red regions under 970-nm excitation. The strong blue-green emission can be explained by a cooperative process between ytterbium ion pairs, leading to emission centered at 514 nm. The additional blue bands as well as green and red emission bands are attributed to the presence of Tm{sup 3+} and Er{sup 3+} traces. The results include absorption and emission curves as well as decay time rates.

  1. Cooperative emission in ion implanted Yb:YAG waveguides

    International Nuclear Information System (INIS)

    Vazquez, G V; Desirena, H; De la Rosa, E; Flores-Romero, E; Rickards, J; Trejo-Luna, R; Marquez, H

    2011-01-01

    In this work, we report the analysis of spectroscopic properties of waveguides fabricated by ion implantation in YAG doped with Yb 3+ ions. Three emission bands were detected in the blue, green and red regions under 970-nm excitation. The strong blue-green emission can be explained by a cooperative process between ytterbium ion pairs, leading to emission centered at 514 nm. The additional blue bands as well as green and red emission bands are attributed to the presence of Tm 3+ and Er 3+ traces. The results include absorption and emission curves as well as decay time rates.

  2. Tapered diode laser pumped 946 nm Nd:YAG laser

    DEFF Research Database (Denmark)

    Cheng, Haynes Pak Hay; Jensen, Ole Bjarlin; Petersen, Paul Michael

    2009-01-01

    We successfully implemented a 946 nm Nd:YAG laser based on a 808 nm tapered diode pump laser. The tapered diode is developed at the Ferdinand-Braun-Institute fur Hochstfrequenztechnik in Germany. Figure 2 shows the experimental setup and results of each pump source coupled into a 1.5 mm crystal...... laser, we show that tapered diode laser pumping potentially increase the power of 946 nm lasers by a factor of two and reduce the threshold by a factor of three....

  3. Treatment of rosacea with long-pulsed Nd: YAG laser

    Directory of Open Access Journals (Sweden)

    Ekin Meşe Say

    2013-03-01

    Full Text Available Background and Design: Rosacea is a chronic inflammatory disorder of the face. There is no curative treatment for the disease. Facial flushing and vascular lesions due to rosacea may significantly affect a patient’s quality of life. Topical and oral antibiotics are not effective for treating rosacea. Currently, laser treatment of vascular lesions has been reported in the literature. We aimed to investigate the efficacy of long-pulse 1064-nm neodymium: YAG (Nd: YAG laser in the treatment of vascular lesions (erythema and telangiectasia in rosacea patients. Materials and Methods: Thirty-nine patients (29 women, 10 men with erythematotelangiectatic rosacea (ETR were recruited into the study. Severity of the disease (ETR-score: 0-3 was assessed for all patients. We used long-pulsed Nd: YAG laser for vascular lesions at 3-4 weeks intervals. The face was divided into seven anatomic regions for evaluation. Assessment was made by comparing pretreatment and posttreatment photographs by using ETR-scores. For evaluating patient satisfaction, a scale of 0 to 3 was used. Results: The patients were divided into three groups according to the ETR scores [ETR-1 (n=12, ETR-2 (n=9, ETR-3 (n=18]. Following an average of 3.95 (2-8 sessions laser treatments, the clinical improvement was statistically significant in all groups (p<0.05. The mean reduction of ETR-score was 91.70% in patients with ETR-1 and. the clinical improvement was to be decreased in severe forms of ETR. The most common sites for the lesions were the malar region, ala nasi and the nasal dorsum, respectively. The lesions on the ala nasi were more recalcitrant to the treatment than those on the other areas. Regarding to physician assessment of treatment’s success, 97% of the patients was associated with moderate and excellent improvement. According to physicians’ assessment, excellent improvement was noticed in 43.58% and, 61.5% of patients reported a high degree of satisfaction with this

  4. Application of YAG laser processing in underwater welding and cutting

    Energy Technology Data Exchange (ETDEWEB)

    Ohwaki, Katsura; Morita, Ichiro; Kojima, Toshio; Sato, Shuichi [Ishikawajima-Harima Heavy Industries Co. Ltd., Tokyo (Japan)

    2002-09-01

    The high-power YAG laser is a new fabrication tool. The laser torch is easy to combine with complex with complex mechanics because of beam delivery through optical fiber. A direct underwater laser welding technology has been developed and applied to the preservation, maintenance and removal of nuclear power plants. For subdividing or removing operations for retirement of plants, the laser cutting properties were confirmed to allow a maximum cutting thickness of 80 mm. For repairing inner surface of stainless steel tanks, an underwater laser welding system using a remote-controlled robot was developed and the high quality of underwater laser welding was confirmed. (author)

  5. Development of YAG laser cutting system for decommissioning nuclear equipments

    International Nuclear Information System (INIS)

    Kasai, Takeshi; Nitta, Kazuhiko; Hosoda, Hiroshi.

    1995-01-01

    Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. As a result, the stainless steel plate with a thickness of 22mm could be cut by using an optical fiber which can flexibly propagate laser power, and possibility of application of this laser cutting system to decommissioning nuclear equipments was verified. (author)

  6. Development of YAG laser cutting system for decommissioning nuclear equipments

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Takeshi [Fuji Electric Co. Research and Development Ltd., Yokosuka, Kanagawa (Japan); Nitta, Kazuhiko; Hosoda, Hiroshi

    1995-07-01

    Technology of remote controlled cutting and reduction of generative secondary products have been required to the cutting system for decommissioning nuclear equipments. At a point of view that laser cutting technology by use of a Nd:YAG laser is effective, we have developed the laser cutting machine and carried out cutting tests for several stainless steel plates. As a result, the stainless steel plate with a thickness of 22mm could be cut by using an optical fiber which can flexibly propagate laser power, and possibility of application of this laser cutting system to decommissioning nuclear equipments was verified. (author).

  7. Neodymium ion diffusion during sintering of Nd : YAG transparent ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Hollingsworth, Joel P; Kuntz, Joshua D; Soules, Thomas F [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550 (United States)

    2009-03-07

    Using an electron microprobe, we measured and characterized the Nd{sup 3+} ion diffusion across a boundary between Nd doped and undoped ceramic yttrium aluminium garnet (YAG) for different temperature ramps and hold times and temperatures. The results show significant Nd ion diffusion on the order of micrometres to tens of micrometres depending on the time and temperature of sintering. The data fit well a model including bulk diffusion, grain boundary diffusion and grain growth. Grain boundary diffusion dominates and grain growth limits grain boundary diffusion by reducing the total cross-sectional area of grain boundaries. (fast track communication)

  8. Comparison of intraocular pressure measurements with the portable PT100 noncontact tonometer and goldmann applanation tonometry.

    Science.gov (United States)

    Salim, Sarwat; Linn, Daniel J; Echols, James R; Netland, Peter A

    2009-01-01

    Noncontact tonometers are useful when regulations preclude use of contact tonometers by medical students and other nonophthalmologists. Our study compared the measurements by the portable, noncontact tonometer (PT100) with Goldmann applanation tonometry (GAT). This was a prospective study of 98 eyes from 98 patients. Intraocular pressure (IOP) was measured by GAT and the PT100 (Reichert, Buffalo, NY). Mean IOP measurements showed no significant differences in measurements performed by the two tonometers (P = 0.64). Measurements by the two tonometers were in agreement by tonometer provides IOP measurements comparable to GAT within the normal range of IOP.

  9. Dynamic contour tonometry vs. non-contact tonometry and their relation with corneal thickness

    OpenAIRE

    Briceño, Adriana; Mas, David; Domenech, Begoña

    2016-01-01

    The purpose of this study is to evaluate the concordance between intraocular pressure (IOP) values obtained with a dynamic contour tonometer (DCT) and a non-contact tonometer (NCT) in healthy patients and to investigate the effect of central corneal thickness (CCT) on IOP readings for each of the two measuring systems. The mean IOP yielded by DCT, NCT and corrected non-contact tonometer (CNCT) was 17.1 mmHg, 15.5 mmHg and 12.2 mmHg, respectively. The average CCT was 563.6 μm and the ocular pu...

  10. Comparative study of three non-contact tonometers and the Goldmann tonometer.

    Science.gov (United States)

    Moreno-Montañés, J; Gómez-Demmel, E; Lajara-Blesa, J; Aliseda-Pérez de Madrid, D

    1994-01-01

    The main objective of this study was to find out how well three non-contact tonometers (Pulsair, Xpert-NCT and CT-20) compare with the Goldmann tonometer (GT). Sensitivity, specificity, positive and negative predictive values were all evaluated for an intraocular pressure (IOP) > or = 21 mm Hg. We also calculated the mean IOP, the correlation and the dispersion of the results. The difficulty in using the instruments, the patient's attitude and subjective comfort of IOP measuring were also evaluated. We describe the advantages and shortcomings of non-contact tonometers as screening tools to detect elevated IOP in the general population.

  11. Acanthamoeba keratitis in a non-contact lens wearer with human immunodeficiency virus

    DEFF Research Database (Denmark)

    Hansen, Birgitte Rønde; Kronborg, Gitte

    2003-01-01

    , and was treated with various topical antibiotics and steroids. 13 months after symptom onset the eye was removed owing to serious scarring of cornea and unbearable pain. Microbiological and histopathological examination of the cornea showed Acanthamoeba. In non-contact lens wearers suffering from Acanthamoeba......Acanthamoeba keratitis is potentially blinding and often associated with contact lens wearing. A human immunodeficiency virus (HIV)-positive patient, a non-contact lens wearer, presented with keratitis. She experienced a protracted course of disease, characterized by exacerbations and remissions...

  12. Studies of non-contact methods for roughness measurements on wood surfaces

    International Nuclear Information System (INIS)

    Lundberg, I.A.S.; Porankiewicz, B.

    1995-01-01

    The quality of wood surfaces after different kinds of machining processes is a property of great importance for the wood processing industries. Present work is a study, whose objective was to evaluate different non-contact methods, for measurement of the quality of the wood surfaces by correlating them with stylus tracing. A number of Scots Pine samples were prepared by different kinds of wood machining processing. Surface roughness measurements were performed, utilizing two optical noncontact methods. The results indicate that the laser scan method can measure surface roughness on sawn wood with a sufficient degree of accuracy. (author) [de

  13. A clinical evaluation of the non-contact tonometer.

    Science.gov (United States)

    Wittenberg, S

    1977-02-01

    Paired non-contact tonometer readings were taken on patients at the Boston City Hospital Eye Clinic before and after routine vision care that included Goldmann tonometry. The variability of NCT readings was determined and comparisons made between readings obtained with the NCT and Goldmann instruments. The regression equation relating the pre-Goldmann NCT findings (N1), to the Goldmann (G), was N1 = 1.01G + 1.97; and the equation relating the post-Goldmann NCT findings (N2), to the Goldman was N2 = .94G + 1.70. The N1 mean was 2.06 mm. higher than the mean G, while the N2 mean was .58 mm. higher than the mean G. The correlation coefficients and standard deviation of the differences for the two comparisons were, .88, 3.91, and .93, 3.07, respectively. The Goldmann findings therefore were seen to agree more closely with the NCT findings taken after them. The linear regression and correlation coefficients between the NCT and the Goldmann were generally in good agreement with those of prior studies, although the standard deviations of the differences between findings were larger in this study. This result is not surprising since no attempt was made to train Goldmann operators to criterion or to limit variability induced by differing observer criteria or by the use of only one Goldmann operator. The operators of the Goldmann tonometer had varying degrees of training as residents in ophthalmology. Interestingly, the agreement between pre-Goldmann NCT and post-Goldmann NCT findings was not good. This suggested that the taking of the Goldmann findings themselves may have had a significant effect on the tonometric readings and that the considerable time that frequently took place between the two sets of NCT readings could have affected the value. The standard deviation of the differences between pre- and post-Goldmann readings on the same patient was 3.27 as compared to that for paired readings which was 2.28. The data also showed a much better agreement between the NCT and

  14. Noncontact measurement of high temperature using optical fiber sensors

    Science.gov (United States)

    Claus, R. O.

    1990-01-01

    The primary goal of this research program was the investigation and application of noncontact temperature measurement techniques using optical techniques and optical fiber methods. In particular, a pyrometer utilizing an infrared optical light pipe and a multiwavelength filtering approach was designed, revised, and tested. This work was motivated by the need to measure the temperatures of small metallic pellets (approximately 3 mm diameter) in free fall at the Microgravity Materials Processing Drop Tube at NASA Marshall Space Flight Center. In addition, research under this program investigated the adaptation of holography technology to optical fiber sensors, and also examined the use of rare-earth dopants in optical fibers for use in measuring temperature. The pyrometer development effort involved both theoretical analysis and experimental tests. For the analysis, a mathematical model based on radiative transfer principles was derived. Key parameter values representative of the drop tube system, such as particle size, tube diameter and length, and particle temperature, were used to determine an estimate of the radiant flux that will be incident on the face of an optical fiber or light pipe used to collect radiation from the incandescent falling particle. An extension of this work examined the advantage of inclining or tilting the collecting fiber to increase the time that the falling particle remains in the fiber field-of-view. Those results indicate that increases in total power collected of about 15 percent may be realized by tilting the fiber. In order to determine the suitability of alternative light pipes and optical fibers, and experimental set-up for measuring the transmittance and insertion loss of infrared fibers considered for use in the pyrometer was assembled. A zirconium fluoride optical fiber and several bundles of hollow core fiber of varying diameters were tested. A prototype two-color pyrometer was assembled and tested at Virginia Tech, and then

  15. Predictive risk factors of postoperative urinary incontinence following holmium laser enucleation of the prostate during the initial learning period

    Directory of Open Access Journals (Sweden)

    Shuichiro Kobayashi

    Full Text Available ABSTRACT Purpose: To determine the predictive factors for postoperative urinary incontinence (UI following holmium laser enucleation of the prostate (HoLEP during the initial learning period. Patients and Methods: We evaluated 127 patients with benign prostatic hyperplasia who underwent HoLEP between January 2011 and December 2013. We recorded clinical variables, including blood loss, serum prostate-specific antigen levels, and the presence or absence of UI. Blood loss was estimated as a decline in postoperative hemoglobin levels. The predictive factors for postoperative UI were determined using a multivariable logistic regression analysis. Results: Postoperative UI occurred in 31 patients (24.4%, but it cured in 29 patients (93.5% after a mean duration of 12 weeks. Enucleation time >100 min (p=0.043 and blood loss >2.5g/dL (p=0.032 were identified as significant and independent risk factors for postoperative UI. Conclusions: Longer enucleation time and increased blood loss were independent predictors of postoperative UI in patients who underwent HoLEP during the initial learning period. Surgeons in training should take care to perform speedy enucleation maneuver with hemostasis.

  16. Line Identification of Atomic and Ionic Spectra of Holmium in the Near-UV. Part I. Spectrum of Ho i

    Energy Technology Data Exchange (ETDEWEB)

    Al-Labady, N.; Özdalgiç, B. [Graduate School of Engineering and Sciences, Istanbul University, TR-34452 Beyazıt, Istanbul (Turkey); Er, A.; Güzelçimen, F.; Öztürk, I. K.; Başar, Gö. [Faculty of Science, Department of Physics, Istanbul University, TR-34134 Vezneciler, Istanbul (Turkey); Kröger, S. [Hochschule für Technik und Wirtschaft Berlin, Wilhelminenhofstr. 75A, D-12459 Berlin (Germany); Kruzins, A.; Tamanis, M.; Ferber, R., E-mail: ikanat@istanbul.edu.tr [Laser Centre, The University of Latvia, Rainis Boulevard 19, LV-1586 Riga (Latvia)

    2017-02-01

    The Fourier Transform spectra of a Holmium hollow cathode discharge lamp have been investigated in the UV spectral range from 25,000 up to 31,530 cm{sup −1} (317 to 400 nm). Two Ho spectra have been measured with neon and argon as buffer gases. Based on the intensity ratios from these two spectra, a distinction was made between atomic and ionic lines (ionic lines are discussed in an accompanying paper). Using the known Ho i energy levels, 71 lines could be classified as transitions of atomic Ho, 34 of which have not been published previously. Another 32 lines, which could not be classified, are listed in the literature and assigned as atomic Ho. An additional 370 spectral lines have been assigned to atomic Ho based on the signal-to-noise ratio in the two spectra measured under different discharge conditions, namely with buffer gases argon and neon, respectively. These 370 lines have not been previously listed in the literature.

  17. Spectroscopic studies of the energy transfer processes important to obtain holmium laser action in the Er:Tm:Ho:YLF

    International Nuclear Information System (INIS)

    Tarelho, Luiz Vicente Gomes

    1995-01-01

    There are several processes of energy transfer between Er, Tm and Ho ions in YLF crystal that could be evaluated using the Foerster-Dexter method. Energy transfer processes, important to understand Holmium laser action, were studied, specially involving the energy transfer between the first excited states of Er and Tm donors and Ho acceptor. The back-transfer processes were evaluated too in order to minimize the system losses. Another important process to understand Ho laser action in the host is the energy diffusion mechanism between donor ions due to excitation migration processes which take place before the energy transfer to Ho. The proposed model of energy transfer was developed to include the diffusion mechanism between donors in the absence and presence of the acceptors. The energy transfer probability was evaluated including the back-transfer processes besides the diffusion assistance. A laser medium model based on the fundamental spectroscopic parameters was used in order to determine the ideal donor acceptor concentrations in order to maximize the laser action of Ho at 2,1 μm. (author)

  18. Influence of Pelvicaliceal Anatomy on Stone Clearance After Flexible Ureteroscopy and Holmium Laser Lithotripsy for Large Renal Stones.

    Science.gov (United States)

    Inoue, Takaaki; Murota, Takashi; Okada, Shinsuke; Hamamoto, Shuzo; Muguruma, Kouei; Kinoshita, Hidefumi; Matsuda, Tadashi

    2015-09-01

    This study was performed to evaluate the impact of pelvicaliceal anatomy on stone clearance in patients with remnant fragments in the lower pole after flexible ureteroscopy and holmium laser lithotripsy (fURSL) for renal stones >15 mm. This retrospective study included 67 patients with radiopaque residual fragments (>2 mm) in the lower pole after fURSL for large renal stones (>15 mm). The preoperative infundibular length (IL), infundibular width (IW), infundibulopelvic angle (IPA), and caliceal pelvic height (CPH) were measured using intravenous urography. Multivariate analysis was performed to determine whether any of these measurements affected stone clearance. Of the 67 patients, 55 (82.1%) were stone free (SF) 3 months after fURSL. The anatomic factors significantly favorable for an SF status were a short IL, broad IW, wide IPA, and low CPH. On multivariate analysis, the IPA had a significant influence on an SF status after fURSL (p=0.010). An IPA renal stones according to our multivariate analysis. Additional studies are required to further evaluate the characteristics of the pelvicaliceal anatomy influencing stone clearance.

  19. Brachytherapy using holmium-166 liquid balloon system for in-stent restenosis: 6 months clinical and angiographic follow-up

    Energy Technology Data Exchange (ETDEWEB)

    Kim, M. H.; Kim, S. K.; Cha, K. S.; Kim, Y. D.; Lee, H. S.; Kang, D. Y. [Donga University College of Medicine, Busan (Korea, Republic of)

    2002-07-01

    In western country, 3 systems of brachytherapy using commercial radioactive source has been established. However, brachytherapy using holmium-166 liquid balloon system (HLBS) for the patient with stent restenosis has not been studied enough. 30 patients (male 23, mean age 58.9 7.7) were enrolled. Target dose was 15 Gy at 1 mm distance from the intimal surface. Clinical diagnoses of the study patients included stable angina 10 and unstable angina 20 patients. Target lesion included LAD 19, LCx 5 and RCA 6 arteries. Pre-brachytherapy treatment included cutting balloon angioplasty in 25, rotational atherectomy in 5 patients. Fractionation and stepping was done in 6 patients each. Follow-up angiography was done in 19 patients. Of them, 4 cases developed angiographic restenosis (21%) including 3 cases of total occlusion. 6 month MACE (major adverse cardiac event) occurred in 5 patients including one sudden cardiac death in a patient with 80 year-old, triple-vessel diseased patient. Vascular brachytherapy using HLBS is a safe and effective treatment modality for in-stent restenosis showing acceptable angiographic and clinical result.

  20. Rebuttal of the existence of solid rare earth bicarbonates and the crystal structure of holmium nitrate pentahydrate

    Energy Technology Data Exchange (ETDEWEB)

    Rincke, Christine; Schmidt, Horst; Voigt, Wolfgang [Institute for Inorganic Chemistry, TU Bergakademie Freiberg (Germany)

    2017-03-16

    The synthesis routes of Gd(HCO{sub 3}){sub 3}.5H{sub 2}O and Ho(HCO{sub 3}){sub 3}.6H{sub 2}O, which are the only known bicarbonates of rare earth metals, were refuted and the published crystal structures were discussed. Because of the structural relationship of Ho(HCO{sub 3}){sub 3}.6H{sub 2}O to rare earth nitrate hexahydrates,[] the synthesis of holmium nitrate hydrate was considered and the crystal structure of Ho(NO{sub 3}){sub 3}.5H{sub 2}O was solved by single crystal X-ray diffraction measurements. Ho(NO{sub 3}){sub 3}.5H{sub 2}O was determined to crystallize in the triclinic space group P1 (no. 2) with a = 6.5680(14) Aa, b = 9.503(2) Aa, c = 10.462(2) Aa, α = 63.739(14) , β = 94.042(2) and γ = 76.000(16) . The crystal structure consists of isolated [Ho(H{sub 2}O){sub 4}(NO{sub 3}){sub 3}] polyhedra and non-coordinating water molecules. It is isotypic to other rare earth nitrate pentahydrates. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. The Impact of Increased Bladder Blood Flow on Storage Symptoms after Holmium Laser Enucleation of the Prostate.

    Directory of Open Access Journals (Sweden)

    Keisuke Saito

    Full Text Available In order to investigate how holmium laser enucleation of the prostate (HoLEP improves urinary storage symptoms, we assessed blood flow in the urinary bladder mucosa of patients with benign prostatic hyperplasia (BPH before and after laser surgery. Seventy-four consecutive patients with BPH (median age 69 years, range; 53-88 underwent HoLEP at our institution and are included in this study. We prospectively assessed the International Prostate Symptom Score (IPSS, IPSS-QOL Score, the Overactive Bladder Symptom Score (OABSS, uroflowmetry, and blood flow in the urinary bladder, before and after surgery. Blood flow in the bladder mucosa was measured using the OMEGA FLOW (OMEGAWAVE, Tokyo, Japan laser Doppler flowmeter. The median volume of the enucleated adenomas was 45.0 g (range: 25.0 to 83.2. The median IPSS improved significantly from 20 (range: 6-35 to 3 (0-22 (p < 0.001; Wilcoxon signed-rank test, as did the storage symptoms score, which decreased from 13 (2-20 to 3 (1-8 (p < 0.001. Median bladder blood flow increased at the trigone from 9.57 ± 0.83 ml/sec to 17.60 ± 1.08 ml/sec. Multiple regression analysis for the improved storage symptom score eliminated all explanatory variables except increased bladder perfusion. The data suggest that HoLEP improves blood flow in the bladder mucosa, which independently leads to the improvement of storage symptoms.

  2. The Impact of Increased Bladder Blood Flow on Storage Symptoms after Holmium Laser Enucleation of the Prostate

    Science.gov (United States)

    Ide, Hisamitsu; Aoki, Hiroaki; Muto, Satoru; Yamaguchi, Raizo; Tsujimura, Akira; Horie, Shigeo

    2015-01-01

    In order to investigate how holmium laser enucleation of the prostate (HoLEP) improves urinary storage symptoms, we assessed blood flow in the urinary bladder mucosa of patients with benign prostatic hyperplasia (BPH) before and after laser surgery. Seventy-four consecutive patients with BPH (median age 69 years, range; 53–88) underwent HoLEP at our institution and are included in this study. We prospectively assessed the International Prostate Symptom Score (IPSS), IPSS-QOL Score, the Overactive Bladder Symptom Score (OABSS), uroflowmetry, and blood flow in the urinary bladder, before and after surgery. Blood flow in the bladder mucosa was measured using the OMEGA FLOW (OMEGAWAVE, Tokyo, Japan) laser Doppler flowmeter. The median volume of the enucleated adenomas was 45.0 g (range: 25.0 to 83.2). The median IPSS improved significantly from 20 (range: 6–35) to 3 (0–22) (p<0.001; Wilcoxon signed-rank test), as did the storage symptoms score, which decreased from 13 (2–20) to 3 (1–8) (p<0.001). Median bladder blood flow increased at the trigone from 9.57±0.83 ml/sec to 17.60±1.08 ml/sec. Multiple regression analysis for the improved storage symptom score eliminated all explanatory variables except increased bladder perfusion. The data suggest that HoLEP improves blood flow in the bladder mucosa, which independently leads to the improvement of storage symptoms. PMID:26090819

  3. Targeting of liver tumour in rats by selective delivery of holmium-166 loaded microspheres: a biodistribution study

    Energy Technology Data Exchange (ETDEWEB)

    Nijsen, F.; Rook, D.; Zonnenberg, B.; Klerk, J. de; Rijk, P. van; Schip, F. van het [Dept. of Nuclear Medicine, University Medical Center, Utrecht (Netherlands); Brandt, C. [Animal Inst., Utrecht Univ. (Netherlands); Meijer, R. [Dept. of Radiology, Univ. Medical Center, Utrecht (Netherlands); Dullens, H. [Dept. of Pathology, Univ. Medical Center, Utrecht (Netherlands); Hennink, W. [Dept. of Pharmaceutics, Utrecht Univ. (Netherlands)

    2001-06-01

    Intra-arterial administration of beta-emitting particles that become trapped in the vascular bed of a tumour and remain there while delivering high doses, represents a unique approach in the treatment of both primary and metastatic liver tumours. Studies on selective internal radiation therapy of colorectal liver metastases using yttrium-90 glass microspheres have shown encouraging results. This study describes the biodistribution of 40-{mu}m poly lactic acid microspheres loaded with radioactive holmium-166, after intra-arterial administration into the hepatic artery of rats with implanted liver tumours. Radioactivity measurements showed >95% retention of injected activity in the liver and its resident tumour. The average activity detected in other tissues was {<=}0.1%ID/g, with incidental exceptions in the lungs and stomach. Very little {sup 166}Ho activity was detected in kidneys (<0.1%ID/g), thereby indicating the stability of the microspheres in vivo. Tumour targeting was very effective, with a mean tumour to liver ratio of 6.1{+-}2.9 for rats with tumour (n=15) versus 0.7{+-}0.5 for control rats (n=6; P<0.001). These ratios were not significantly affected by the use of adrenaline. Histological analysis showed that five times as many large (>10) and medium-sized (4-9) clusters of microspheres were present within tumour and peritumoural tissue, compared with normal liver. Single microspheres were equally dispersed throughout the tumour, as well as normal liver parenchyma. (orig.)

  4. Thermal effects associated with the Nd/YAG dental laser.

    Science.gov (United States)

    von Fraunhofer, J A; Allen, D J

    1993-01-01

    The heat produced at the dentinal pulpal wall opposite the irradiation site was measured during etching of dental enamel with an Nd:YAG laser in preparation for direct bonding of orthodontic appliances. Forty extracted human teeth were randomly divided into four groups of 10 teeth. Within each group, the buccal surfaces of 5 teeth and the lingual surfaces of the other 5 teeth were laser treated for 12 sec. Irradiation was performed with a commercial Nd:YAG laser at the power settings of 80mJ, 1W, 2W and 3W. Prior to irradiation, an occlusal access preparation was made into the pulp in order to facilitate the placement of a thermocouple for measurement of temperature changes at the dentinal pulpal wall opposite the irradiation site. The thermocouple was held against the dentinal pulpal wall and the resulting temperature changes were recorded. Heating effects at the dentinal pulpal wall on both buccal and lingual surfaces showed an increase in heat as a function of the increase in power output from the laser unit (p damage to the pulp tissue immediately opposite the site of laser irradiation.

  5. Nd:YAG laser in art works restoration

    Directory of Open Access Journals (Sweden)

    Flores, T.

    1998-04-01

    Full Text Available Laser cleaning in works of art has a number of advantages over traditional techniques of restoration. In this article, the technique used and the physical mechanisms that explain the process of ablation of pollutants are described. The results obtained in the cleaning of statues of marble and alabaster are exposed as well as oil-painting restoration. In this last specific case, the Nd:YAG laser is used with successful results.

    La limpieza de obras de arte por láser presenta una serie de ventajas sobre técnicas tradicionales de restauración. En el presente trabajo se describen la técnica empleada y los mecanismos físicos que explican el proceso de ablación de contaminantes. Se reportan los resultados alcanzados en la limpieza de estatuas de mármol y alabastro, así como en la restauración de pintura al óleo. En este último caso, se emplea por primera vez el láser de Nd:YAG con resultados ventajosos.

  6. YAG laser cladding to heat exchanger flange in actual plant

    International Nuclear Information System (INIS)

    Toshio, Kojima

    2001-01-01

    This paper is a sequel to ''Development of YAG Laser Cladding Technology to Heat Exchanger Flange'' presented in ICONE-8. A YAG Laser cladding technology is a permanent repairing and preventive maintenance method for heat exchanger's flange (channel side) seating surface which is degraded by the corrosion in long term operation. The material of this flange is carbon steel, and that of cladding wire is type 316 stainless steel so as to have high corrosion resistance. In former paper above, the soundness of cladding layers were presented to be verified. This channel side flange is bolted with tube sheet (shell side) through metal gasket. As the tube sheet side is already cladded a corrosion resistant material, it needs to apply the repairing and preventive maintenance method to only channel side. In 2000 this technology had been performed to the actual heat exchanger (Residual Heat Removal Heat Exchanger; RHR Hx) flange in domestic nuclear power plant. This paper described the outline, special equipment, and our total evaluation for this actual laser cladding work. And also several technical subjects which we should solve and/or improve for the next project was presented. (author)

  7. Development of underwater YAG laser repair welding robots for tanks

    International Nuclear Information System (INIS)

    Miwa, Yasuhiro; Satoh, Syuichi; Ito, Kosuke; Kochi, Tsutomu; Kojima, Toshio; Ohwaki, Katsura; Morita, Ichiro

    1999-01-01

    A remote-controlled repair welding robot which uses YAG laser welding technology in underwater environment was developed. This is an underwater robot technology combined with a laser welding technology. This report will describe the structure and performance of this robot, and the welding test results. The repair welding robot consists of two parts. The one is driving equipment, and the other is welding unit. It can swim in the tank, move around the tank wall, and stay on the welding area. After that it starts YAG laser repair welding. The target of this technology is inner surface repair of some tanks made of austenitic stainless steel, for example RW (Radioactive Waste) tanks. A degradation by General Corrosion and so on might be occurred at inner surface of these tanks in BWR type nuclear power plants. If the damaged area is wide, repair welding works are done. Some workers go into the tank and set up scaffolding after full drainage. In many cases it spends too much time for draining water and repair welding preparation. If the repair welding works can be done in underwater environment, the outage period will be reduced. This is a great advantage. (author)

  8. Quantitative sub-surface and non-contact imaging using scanning microwave microscopy

    International Nuclear Information System (INIS)

    Gramse, Georg; Kasper, Manuel; Hinterdorfer, Peter; Brinciotti, Enrico; Rankl, Christian; Kienberger, Ferry; Lucibello, Andrea; Marcelli, Romolo; Patil, Samadhan B.; Giridharagopal, Rajiv

    2015-01-01

    The capability of scanning microwave microscopy for calibrated sub-surface and non-contact capacitance imaging of silicon (Si) samples is quantitatively studied at broadband frequencies ranging from 1 to 20 GHz. Calibrated capacitance images of flat Si test samples with varying dopant density (10 15 –10 19 atoms cm −3 ) and covered with dielectric thin films of SiO 2 (100–400 nm thickness) are measured to demonstrate the sensitivity of scanning microwave microscopy (SMM) for sub-surface imaging. Using standard SMM imaging conditions the dopant areas could still be sensed under a 400 nm thick oxide layer. Non-contact SMM imaging in lift-mode and constant height mode is quantitatively demonstrated on a 50 nm thick SiO 2 test pad. The differences between non-contact and contact mode capacitances are studied with respect to the main parameters influencing the imaging contrast, namely the probe tip diameter and the tip–sample distance. Finite element modelling was used to further analyse the influence of the tip radius and the tip–sample distance on the SMM sensitivity. The understanding of how the two key parameters determine the SMM sensitivity and quantitative capacitances represents an important step towards its routine application for non-contact and sub-surface imaging. (paper)

  9. Noncontact AFM Imaging of Atomic Defects on the Rutile TiO2 (110) Surface

    DEFF Research Database (Denmark)

    Lauritsen, Jeppe Vang

    2015-01-01

    The atomic force microscope (AFM) operated in the noncontact mode (nc-AFM) offers a unique tool for real space, atomic-scale characterisation of point defects and molecules on surfaces, irrespective of the substrate being electrically conducting or non-conducting. The nc-AFM has therefore in rece...

  10. Simultaneous Epicardial and Noncontact Endocardial Mapping of the Canine Right Atrium: Simulation and Experiment

    Science.gov (United States)

    Sabouri, Sepideh; Matene, Elhacene; Vinet, Alain; Richer, Louis-Philippe; Cardinal, René; Armour, J. Andrew; Pagé, Pierre; Kus, Teresa; Jacquemet, Vincent

    2014-01-01

    Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes), noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter), and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression), activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa), a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments) and 0.96 (simulation) between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments) and 0.92 (simulation) between ATa values. Despite distance (balloon-atrial wall) and dimension reduction (64 electrodes), some information about atrial repolarization remained present in noncontact signals. PMID:24598778

  11. [Evaluation of accuracy of measuring intraocular pressure by handheld non-contact applanation tonometer].

    Science.gov (United States)

    Chen, X; Peng, D; Zhou, W; Zhong, Y

    1995-06-01

    To evaluate the accuracy of measuring intraocular pressure by handheld non-contact applanation tonometer. 58 patients' (113 eyes) intraocular pressure were measured by Keeler, non-contact tonometer and R 900 Goldmann applanation tonometer and the results of measurement of intraocular pressure by the two kinds of tonometers were compared. The mean intraocular pressure measured by non-contact is 16.31 +/- 5.59 mmHg and 17.49 +/- 6.13 mmHg (1 mmHg = 0.1333 kPa) by Goldmann applanation tonometer, respectively. There was no statistical significance to be found (P > 0.05) between the two methods. By linear correlation and regression analysis, a positive correlation was found between the two methods (r = 0.8942, b = 0.8154). The handheld non-contact tonometer has the same accuracy and reliability of measurement of intraocular pressure comparing with Goldmann applanation tonometer, and it can be used in glaucoma clinic and screening.

  12. Comparison of intraocular pressure measurements with the portable PT100 noncontact tonometer and Goldmann applanation tonometry

    Directory of Open Access Journals (Sweden)

    Sarwat Salim

    2009-05-01

    Full Text Available Sarwat Salim, Daniel J Linn, James R Echols II, Peter A NetlandHamilton Eye Institute, University of Tennessee Health Science Center, Memphis, TN, USAPurpose: Noncontact tonometers are useful when regulations preclude use of contact tonometers by medical students and other nonophthalmologists. Our study compared the measurements by the portable, noncontact tonometer (PT100 with Goldmann applanation tonometry (GAT. Methods: This was a prospective study of 98 eyes from 98 patients. Intraocular pressure (IOP was measured by GAT and the PT100 (Reichert, Buffalo, NY.Results: Mean IOP measurements showed no significant differences in measurements performed by the two tonometers (P = 0.64. Measurements by the two tonometers were in agreement by ≤3 mmHg in 92.8% of eyes. Linear regression analysis of PT100 vs GAT measurements revealed a slope of 0.98 with r2 = 0.58. Bland–Altman analysis showed a mean difference of measurements by GAT and PT100 of -0.3 mmHg with two standard deviation = 7.1 mmHg.Conclusion: The portable noncontact PT100 tonometer provides IOP measurements comparable to GAT within the normal range of IOP. Keywords: applanation tonometer, intraocular pressure, noncontact tonometry

  13. Accuracy and reliability of the Keeler Pulsair EasyEye non-contact tonometer.

    Science.gov (United States)

    Ogbuehi, Kelechi C; Almubrad, Turki M

    2008-01-01

    To evaluate the accuracy and reliability of the Keeler Pulsair EasyEye noncontact tonometer in a normotensive population. This masked prospective clinical study included 72 right eyes of 72 subjects. Two sets of intraocular pressure measurements were made 1 week apart. Intraocular pressure assessment with the Goldmann tonometer was always subsequent to that with the noncontact tonometer. Each method was assessed for within-session and test-retest repeatability and both methods were assessed for limits of agreement, twice. The level of significance for this study was 0.05. Both methods were repeatable within-sessions to within +/-2 mm Hg, and between sessions to within +/-3 mm Hg. Neither the within-session differences nor the between session differences differed significantly between the Goldmann tonometer and the Pulsair EasyEye noncontact tonometer. The mean differences (+/-SD) between both methods (0.1 +/- 1.6 mm Hg and 0.05 +/- 1.7 mm Hg, for the first and second sessions, respectively) were not statistically significant, but the intraocular pressure measured with the Pulsair EasyEye tonometer was consistently higher than that measured with the Goldmann tonometer. The Pulsair EasyEye noncontact tonometer is considered an accurate reliable method in the normotensive population studied but because of a systematic bias in a small number of subjects, it cannot be used interchangeably with the Goldmann tonometer.

  14. [Comparative pressure measurements with the non-contact tonometer and the Goldmann applanation tonometer].

    Science.gov (United States)

    Langmann, G; Schuhmann, G; Schwaiger, W

    1985-11-01

    The intraocular pressure of 400 patients was measured with both the Non-Contact Tonometer II (NCT II) and the Goldmann applanation tonometer (GAT) and was statistically evaluated. The clinical experience gained, as well as advantages and limitations in application, are discussed.

  15. Simultaneous epicardial and noncontact endocardial mapping of the canine right atrium: simulation and experiment.

    Science.gov (United States)

    Sabouri, Sepideh; Matene, Elhacene; Vinet, Alain; Richer, Louis-Philippe; Cardinal, René; Armour, J Andrew; Pagé, Pierre; Kus, Teresa; Jacquemet, Vincent

    2014-01-01

    Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes), noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter), and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression), activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa), a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments) and 0.96 (simulation) between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments) and 0.92 (simulation) between ATa values. Despite distance (balloon-atrial wall) and dimension reduction (64 electrodes), some information about atrial repolarization remained present in noncontact signals.

  16. Simultaneous epicardial and noncontact endocardial mapping of the canine right atrium: simulation and experiment.

    Directory of Open Access Journals (Sweden)

    Sepideh Sabouri

    Full Text Available Epicardial high-density electrical mapping is a well-established experimental instrument to monitor in vivo the activity of the atria in response to modulations of the autonomic nervous system in sinus rhythm. In regions that are not accessible by epicardial mapping, noncontact endocardial mapping performed through a balloon catheter may provide a more comprehensive description of atrial activity. We developed a computer model of the canine right atrium to compare epicardial and noncontact endocardial mapping. The model was derived from an experiment in which electroanatomical reconstruction, epicardial mapping (103 electrodes, noncontact endocardial mapping (2048 virtual electrodes computed from a 64-channel balloon catheter, and direct-contact endocardial catheter recordings were simultaneously performed in a dog. The recording system was simulated in the computer model. For simulations and experiments (after atrio-ventricular node suppression, activation maps were computed during sinus rhythm. Repolarization was assessed by measuring the area under the atrial T wave (ATa, a marker of repolarization gradients. Results showed an epicardial-endocardial correlation coefficients of 0.80 and 0.63 (two dog experiments and 0.96 (simulation between activation times, and a correlation coefficients of 0.57 and 0.46 (two dog experiments and 0.92 (simulation between ATa values. Despite distance (balloon-atrial wall and dimension reduction (64 electrodes, some information about atrial repolarization remained present in noncontact signals.

  17. Noncontact atomic force microscopy in liquid environment with quartz tuning fork and carbon nanotube probe

    DEFF Research Database (Denmark)

    Kageshima, M.; Jensenius, Henriette; Dienwiebel, M.

    2002-01-01

    A force sensor for noncontact atomic force microscopy in liquid environment was developed by combining a multiwalled carbon nanotube (MWNT) probe with a quartz tuning fork. Solvation shells of octamethylcyclotetrasiloxane surface were detected both in the frequency shift and dissipation. Due to t...

  18. Investigation of holmium-doped zirconium oxide ceramic phosphor as an ultraviolet wavelength-discriminating laser beam viewer

    Science.gov (United States)

    Yamanoi, Kohei; Hori, Tatsuhiro; Minami, Yuki; Empizo, Melvin John F.; Luong, Mui Viet; Shiro, Atsushi; Watanabe, Jun; Iwano, Keisuke; Iwasa, Yuki; Cadatal-Raduban, Marilou; Gabayno, Jacque Lynn; Shimizu, Toshihiko; Sarukura, Nobuhiko; Norimatsu, Takayoshi

    2018-01-01

    We report the fluorescence spectra of ZrO2 and trivalent Ho-doped ZrO2 ceramics under ultraviolet (UV) excitation at 213, 266, and 355 nm wavelengths. The Ho3+-doped ZrO2 ceramics exhibited varying fluorescence color tones depending on the excitation wavelength used. The different color tones match the fluorescence spectrum characteristics at each excitation wavelength. Our results demonstrate that Ho3+-doped ZrO2 ceramics can discriminate between UV light, specifically the third, fourth, and fifth harmonics of a Nd:YAG laser. It can potentially be used for developing UV laser beam viewers to aid laser alignment.

  19. Growth, optical and EPR studies of {sup 151}Eu{sup 2+}:YAG single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Petrosyan, A.G., E-mail: pet@ipr.sci.am [Institute for Physical Research, National Academy of Sciences, Ashtarak, 0203 (Armenia); Asatryan, H.R. [Ioffe Physical-Technical Institute, Politekhnicheskaya ul. 26, St. Petersburg, 194021 (Russian Federation); Hovhannesyan, K.L.; Derdzyan, M.V. [Institute for Physical Research, National Academy of Sciences, Ashtarak, 0203 (Armenia); Feofilov, S.P. [Ioffe Physical-Technical Institute, Politekhnicheskaya ul. 26, St. Petersburg, 194021 (Russian Federation); Eganyan, A.V.; Sargsyan, R.S. [Institute for Physical Research, National Academy of Sciences, Ashtarak, 0203 (Armenia)

    2017-01-01

    Single crystals of {sup 151}Eu:YAG were grown by the vertical Bridgman method using Eu{sub 2}O{sub 3} with isotopic enrichment of {sup 151}Eu of 97.5%. Additional Hf{sup 4+}or Si{sup 4+} ions were introduced to favor a high concentrations of Eu{sup 2+}. As compared to Eu:YAG with natural isotope composition, the EPR spectra of YAG doped with {sup 151}Eu isotope show a reduced number of hyperfine structure components and a well-resolved structure of a bigger number of electronic transitions. Optical properties of obtained crystals and the effects of heat treatments under oxidizing and reducing conditions are reported. Based on the analysis of Eu{sup 3+} distribution in oxidized Eu,Hf:YAG, in comparison to that in Eu:YAG, the concentration of Eu{sup 2+} in as-grown Eu,Hf:YAG is determined. - Highlights: • YAG:Eu,Hf single crystals containing only {sup 151}Eu isotopes were prepared. • isotopic enriched crystals gave a well-resolved EPR hyperfine structure of Eu{sup 2+} centers. • the redox ratio was followed through the Eu{sup 2+} associated absorption band at 250 nm. • the band intensities at 378 nm correlate with the Eu{sup 2+} concentration.

  20. Improved protein structure reconstruction using secondary structures, contacts at higher distance thresholds, and non-contacts.

    Science.gov (United States)

    Adhikari, Badri; Cheng, Jianlin

    2017-08-29

    Residue-residue contacts are key features for accurate de novo protein structure prediction. For the optimal utilization of these predicted contacts in folding proteins accurately, it is important to study the challenges of reconstructing protein structures using true contacts. Because contact-guided protein modeling approach is valuable for predicting the folds of proteins that do not have structural templates, it is necessary for reconstruction studies to focus on hard-to-predict protein structures. Using a data set consisting of 496 structural domains released in recent CASP experiments and a dataset of 150 representative protein structures, in this work, we discuss three techniques to improve the reconstruction accuracy using true contacts - adding secondary structures, increasing contact distance thresholds, and adding non-contacts. We find that reconstruction using secondary structures and contacts can deliver accuracy higher than using full contact maps. Similarly, we demonstrate that non-contacts can improve reconstruction accuracy not only when the used non-contacts are true but also when they are predicted. On the dataset consisting of 150 proteins, we find that by simply using low ranked predicted contacts as non-contacts and adding them as additional restraints, can increase the reconstruction accuracy by 5% when the reconstructed models are evaluated using TM-score. Our findings suggest that secondary structures are invaluable companions of contacts for accurate reconstruction. Confirming some earlier findings, we also find that larger distance thresholds are useful for folding many protein structures which cannot be folded using the standard definition of contacts. Our findings also suggest that for more accurate reconstruction using predicted contacts it is useful to predict contacts at higher distance thresholds (beyond 8 Å) and predict non-contacts.

  1. Assessment of the accuracy and reliability of the Topcon CT80 non-contact tonometer.

    Science.gov (United States)

    Ogbuehi, Kelechi C

    2006-09-01

    The reliability of non-contact tonometers has been reported extensively in the literature. This study was designed to assess reliability of the new Topcon CT80 non-contact tonometer in normotensive subjects, using the Goldmann tonometer as the standard. The accuracy of the Topcon CT 80 non-contact tonometer was assessed by comparing its IOP assessments with those of the Goldmann applanation tonometer, on 60 right eyes of young healthy subjects with normal intraocular pressures. Each subject's intraocular pressure was assessed with each technique on two separate occasions, one week apart. The reliability of each technique was determined by the assessment of its inter-session repeatability using the Bland-Altman method. The 95 per cent limits of agreement for the two methods were also determined. No statistically significant difference was found between the average intraocular pressures measured with the two techniques (p > 0.05). The inter-session repeatability indices for the two techniques did not differ significantly (p > 0.05). The mean difference in intraocular measurements between the two techniques was 0.2 +/- 1.5 mmHg (mean +/- SD) and the 95 per cent limits of agreement were -3.14 and +2.74 mmHg, with the non-contact tonometer returning higher readings than the Goldmann tonometer. In this sample of normotensive subjects, the Topcon CT80 non-contact tonometer proved to be accurate and as reliable as the Goldmann tonometer in the assessment of intraocular pressure. Thus, it can be used as an objective clinical method for the assessment of normal intraocular pressure.

  2. Ocular surface displacement with and without contact lenses during non-contact tonometry.

    Directory of Open Access Journals (Sweden)

    Ulfah Rimayanti

    Full Text Available PURPOSE: To evaluate the displacement of the central ocular surface during non-contact tonometry with and without soft contact lenses and determine the factors associated with the displacement of the central ocular surface and intraocular pressure (IOP reading changes caused by wearing soft contact lenses (CLs. METHODS: One eye each in 21 subjects was studied. The cornea was photographed using a high-speed camera at 5,000 frames/sec during non-contact tonometry without contact lenses (NCL, with -5.0 diopters (D, -0.5 D and +5.0 D CL. The displacement of the ocular surface and the factors affecting displacement at the IOP reading and maximum displacement time were investigated. RESULTS: The IOP readings while wearing +5 D CL were significantly higher than those obtained while wearing -5 D CL. The ocular surface displacement between +5 D CL and other groups were significantly different. A significant positive correlation was found between the ocular surface displacement of subjects at the IOP reading time and the IOP obtained with the non-contact tonometer. A significant negative correlation was found between the ocular surface curvature and the IOP obtained using the non-contact tonometer. The radius of curvature of the ocular surface affected the displacement during the IOP reading and maximum displacement time. CONCLUSIONS: Our results indicate that soft contact lens use changes the ocular surface behavior and IOP readings during non-contact tonometry. The radius of curvature of the eye affects the ocular surface displacement and IOP readings in this situation.

  3. Ocular surface displacement with and without contact lenses during non-contact tonometry.

    Science.gov (United States)

    Rimayanti, Ulfah; Kiuchi, Yoshiaki; Uemura, Shohei; Takenaka, Joji; Mochizuki, Hideki; Kaneko, Makoto

    2014-01-01

    To evaluate the displacement of the central ocular surface during non-contact tonometry with and without soft contact lenses and determine the factors associated with the displacement of the central ocular surface and intraocular pressure (IOP) reading changes caused by wearing soft contact lenses (CLs). One eye each in 21 subjects was studied. The cornea was photographed using a high-speed camera at 5,000 frames/sec during non-contact tonometry without contact lenses (NCL), with -5.0 diopters (D), -0.5 D and +5.0 D CL. The displacement of the ocular surface and the factors affecting displacement at the IOP reading and maximum displacement time were investigated. The IOP readings while wearing +5 D CL were significantly higher than those obtained while wearing -5 D CL. The ocular surface displacement between +5 D CL and other groups were significantly different. A significant positive correlation was found between the ocular surface displacement of subjects at the IOP reading time and the IOP obtained with the non-contact tonometer. A significant negative correlation was found between the ocular surface curvature and the IOP obtained using the non-contact tonometer. The radius of curvature of the ocular surface affected the displacement during the IOP reading and maximum displacement time. Our results indicate that soft contact lens use changes the ocular surface behavior and IOP readings during non-contact tonometry. The radius of curvature of the eye affects the ocular surface displacement and IOP readings in this situation.

  4. Synthesis of highly sinterable YAG nanopowders by a modified co-precipitation method

    International Nuclear Information System (INIS)

    Chen, Zhi-Hui; Yang, Yun; Hu, Zhang-Gui; Li, Jiang-Tao; He, Shu-Li

    2007-01-01

    A hydrate precursor of yttrium aluminum garnet (YAG) was synthesized by a modified co-precipitation method, in which n-butanol was employed as a low-cost recyclable dehydration solvent. A mixed solution of ethanol and ammonia were used as precipitant. Pure YAG phase appeared after the as-prepared precursors being calcined at 850 o C for 2 h. The nanocrystalline YAG particles calcined at 1100 o C were well dispersed with average diameter of about 40 nm, which can be densified to transparency under vacuum sintering at 1700 o C for 5 h with TEOS as sintering additive

  5. Improvement of the technique in treatment of internal hemorrhoids with Nd:YAG laser

    Science.gov (United States)

    Bao, Xiao-qing; Zhu, Jing; Shi, Hong-Min

    2005-07-01

    Objective: To observe and study the improvement of the technique in treatment of internal hemorrhoids with Nd:YAG laser and evaluate the effective rate. Methods: 60 patients of internal hemorrhoids were treated with Nd:YAG laser (10-15mw) irradiating on the mucosa of the lesions. Results: Among 60 patients, 57 patients were primarily cured with one treatment, 3 patients were primarily cured with two treatments. The effective rate was 95% with one treatment, and it reached to 100% with two treatments. Conclusions: the improvement of the technique in treatment of internal hemorrhoids with Nd:YAG laser is effective and easy to operate.

  6. New pulsed YAG laser performances in cutting thick metallic materials for nuclear applications

    International Nuclear Information System (INIS)

    Alfille, J.P.; Prunele, D. de; Pilot, G.

    1996-01-01

    The purpose of this study was to evaluate the capacities of the pulsed YAG laser thick cutting on metallic material and to compare with the CO 2 laser capacities. Stainless steel (304L) cutting tests were made in air and underwater using CO 2 and YAG lasers. A performance assessment was made for each laser and the wastes produced in the cutting operation were measured and the gases and the aerosols analyzed. The results show that the pulsed YAG laser is high performance tool for thick cutting and particularly attractive for nuclear applications

  7. Time-resolved luminescent spectroscopy of YAG:Ce single crystal and single crystalline films

    International Nuclear Information System (INIS)

    Zorenko, Yu.; Gorbenko, V.; Savchyn, V.; Vozniak, T.; Puzikov, V.; Danko, A.; Nizhankovski, S.

    2010-01-01

    The peculiarities of the luminescence and energy transfer from YAG host to the emission centers formed by the Y Al antisite defects and Ce 3+ ions have been studied in YAG:Ce single crystals, grown from the melt by modified Bridgman method in Ar and CO 2 + H 2 atmospheres, and YAG:Ce single crystalline film, grown by liquid phase epitaxy method, using the comparative time-resolved luminescent spectroscopy under excitation by synchrotron radiation in the range of fundamental adsorption of this garnet.

  8. In vitro studies with a pulsed neodymium/YAG laser.

    Science.gov (United States)

    Venkatesh, S; Guthrie, S; Foulds, W S; Lee, W R; Cruickshank, F R; Bailey, R T

    1985-02-01

    The relationships between the destructive effects of Q-switched Nd/YAG laser pulses and a number of experimental parameters were studied for various target materials including in particular excised, fixed samples of human trabecular meshwork. The laser parameters altered were the pulse energy, the convergence angle of the focused beam, and the position of the focus of the beam relative to the target's axial position. The main finding was that it was possible to make deep holes, of a diameter less than 100 micron, in virtually transparent samples of trabecular meshwork with a laser delivery system of 6 degrees convergence and pulse energies of 14 mJ or more. The relevance of this and the other experimental results to the development of a reliable system for performing internal trabeculotomies for the treatment of open-angle glaucoma is presented.

  9. Numerical simulation of a battlefield Nd:YAG laser

    Science.gov (United States)

    Henriksson, Markus; Sjoqvist, Lars; Uhrwing, Thomas

    2005-11-01

    A numeric model has been developed to identify the critical components and parameters in improving the output beam quality of a flashlamp pumped Q-switched Nd:YAG laser with a folded Porro-prism resonator and polarization output coupling. The heating of the laser material and accompanying thermo-optical effects are calculated using the finite element partial differential equations package FEMLAB allowing arbitrary geometries and time distributions. The laser gain and the cavity are modeled with the physical optics simulation code GLAD including effects such as gain profile, thermal lensing and stress-induced birefringence, the Pockels cell rise-time and component aberrations. The model is intended to optimize the pumping process of an OPO providing radiation to be used for ranging, imaging or optical countermeasures.

  10. Er:YAG laser for endodontics: efficiency and safety

    Science.gov (United States)

    Hibst, Raimund; Stock, Karl; Gall, Robert; Keller, Ulrich

    1997-12-01

    Recently it has been shown that bacterias can be sterilized by Er:YAG laser irradiation. By optical fiber transmission the bactericidal effect can also be used in endodontics. In order to explore potential laser parameters, we further investigated sterilization of caries and measured temperatures in models simulating endodontic treatment. It was found out that the bactericidal effect is cumulative, with single pulses being active. This offers to choose all laser parameters except pulse energy (radiant exposure) from technical, practical or safety considerations. For clinical studies the following parameter set is proposed for efficient and safe application (teeth with a root wall thickness > 1 mm, and prepared up to ISO 50): pulse energy: 50 mJ, repetition rate: 15 Hz, fiber withdrawal velocity: 2 mm/s. With these settings 4 passes must be performed to accumulate the total dose for sterilization.

  11. Single, composite, and ceramic Nd:YAG 946-nm lasers

    Science.gov (United States)

    Lan, Rui-Jun; Yang, Guang; Zheng-Ping, Wang

    2015-06-01

    Single, composite crystal and ceramic continuous wave (CW) 946-nm Nd:YAG lasers are demonstrated, respectively. The ceramic laser behaves better than the crystal laser. With 5-mm long ceramic, a CW output power of 1.46 W is generated with an optical conversion efficiency of 13.9%, while the slope efficiency is 17.9%. The optimal ceramic length for a 946-nm laser is also calculated. Project supported by the National Natural Science Foundation of China (Grant No. 61405171), the Natural Science Foundation of Shandong Province, China (Grant No. ZR2012FQ014), and the Science and Technology Program of the Shandong Higher Education Institutions of China (Grant No. J13LJ05).

  12. Precision cutting and drilling with the Nd-YAG laser

    International Nuclear Information System (INIS)

    Lingenfelter, A.C.; Anglin, C.D.; Westrich, C.N.; Murchie, J.R.

    1986-01-01

    The Laser Processing Facility of the Materials Fabrication Division of Lawrence Livermore National Laboratory has two pulsed Nd-YAG lasers mounted on machine tool bases. Over the years the authors have had requirements for cutting a wide variety of materials, frequently to very tight dimensional tolerances. They have found that the laser process is particularly well suited for two application areas; (1) for thin cross sections of most all materials, and (2) for refractory metals and ceramics such as tungsten, tantalum, and molybdenum, silicon wafers, alumina, and graphite foil. Some of these materials are difficult if not impossible to cut and drill in any other manner. Examples of each of these types of applications are sighted. Data are presented to illustrate the effects and interactions of laser parameter variables such as aperturing, choice of lenses, focus, pulse length, and energy level. Examples of applications are shown

  13. Intelligent monitoring of YAG laser welding on steam generator tubes

    International Nuclear Information System (INIS)

    Hosaka, Shigetaka; Nagura, Yasumi; Ishide, Takashi; Nagashima, Tadashi; Akaba, Takashi

    1992-01-01

    The 'KASHIKOKI' intelligent device for monitoring the YAG laser welding of steam generator tubes is described in this paper. The 'KASHIKOKI', it monitors the series of six channels, for example, the reflected laser beam and the welding speed, etc. It learns the normal criteria and the anomalous criteria of welding, and discriminates between normal and anomalous welding using the learned criteria, and distinguishes the anomaly into several types. As the results of evaluation test, the degree of correspondence between this device and an expert is about 90%. This paper describes the new methods the multi-variate analysis model for discriminating between normal and anomalous welding, and a neural network model for distinguishing the types of anomaly. (author)

  14. Segmental irradiation of the bladder with neodymium YAG laser irradiation

    International Nuclear Information System (INIS)

    McPhee, M.S.; Mador, D.R.; Tulip, J.; Ritchie, B.; Moore, R.; Lakey, W.H.

    1982-01-01

    The Neodymium YAG laser energy source can be readily adapted for cystoscopic use by some simple modifications of existing urologic equipment. Both the fiberoptic resectoscope and a deflecting cystourethroscope have been adapted for this purpose. Fixation of the fiber tip 1 cm. from the target and use of a divergent beam of 36 degrees allows the delivery of standardized dosage to a relatively large bladder tissue volume. Animal experiments involving 35 mongrel dogs established that repetitive overlapping doses of 200 joules ech can successfully treat a large area of bladder resulting in a full thickness bladder wall injury. This technique has been used in 4 high risk patients with infiltrating bladder cancer without adverse sequelae. The ability to reliably produce a full thickness lesion may give this modality a therapeutic advantage over conventional cautery techniques especially for the treatment of residual infiltrative carcinoma

  15. High-average-power diode-pumped Yb: YAG lasers

    International Nuclear Information System (INIS)

    Avizonis, P V; Beach, R; Bibeau, C M; Emanuel, M A; Harris, D G; Honea, E C; Monroe, R S; Payne, S A; Skidmore, J A; Sutton, S B

    1999-01-01

    A scaleable diode end-pumping technology for high-average-power slab and rod lasers has been under development for the past several years at Lawrence Livermore National Laboratory (LLNL). This technology has particular application to high average power Yb:YAG lasers that utilize a rod configured gain element. Previously, this rod configured approach has achieved average output powers in a single 5 cm long by 2 mm diameter Yb:YAG rod of 430 W cw and 280 W q-switched. High beam quality (M(sup 2)= 2.4) q-switched operation has also been demonstrated at over 180 W of average output power. More recently, using a dual rod configuration consisting of two, 5 cm long by 2 mm diameter laser rods with birefringence compensation, we have achieved 1080 W of cw output with an M(sup 2) value of 13.5 at an optical-to-optical conversion efficiency of 27.5%. With the same dual rod laser operated in a q-switched mode, we have also demonstrated 532 W of average power with an M(sup 2) and lt; 2.5 at 17% optical-to-optical conversion efficiency. These q-switched results were obtained at a 10 kHz repetition rate and resulted in 77 nsec pulse durations. These improved levels of operational performance have been achieved as a result of technology advancements made in several areas that will be covered in this manuscript. These enhancements to our architecture include: (1) Hollow lens ducts that enable the use of advanced cavity architectures permitting birefringence compensation and the ability to run in large aperture-filling near-diffraction-limited modes. (2) Compound laser rods with flanged-nonabsorbing-endcaps fabricated by diffusion bonding. (3) Techniques for suppressing amplified spontaneous emission (ASE) and parasitics in the polished barrel rods

  16. Initial Clinical Experience with a Modulated Holmium Laser Pulse—Moses Technology: Does It Enhance Laser Lithotripsy Efficacy?

    Directory of Open Access Journals (Sweden)

    Michael Mullerad

    2017-10-01

    Full Text Available Objective The Lumenis® High-power Holmium Laser (120H has a unique modulated pulse mode, Moses™ technology. Moses technology modulates the laser pulse to separate the water (vapor bubble, then deliver the remaining energy through the bubble. Proprietary laser fibers were designed for the Moses technology. Our aim was to compare stone lithotripsy with and without the Moses technology. Methods We designed a questionnaire for the urologist to fill immediately after each ureteroscopy in which the Lumenis 120H was used. We compared procedures with (n=23 and without (n=11 the use of Moses technology. Surgeons ranked the Moses technology in 23 procedures, in comparison to regular lithotripsy (worse, equivalent, better, much better. Laser working time and energy use were collected from the Lumenis 120H log. Results During 4 months, five urologists used the Lumenis 120H in 34 ureteroscopy procedures (19 kidney stones, 15 ureteral stones; 22 procedures with a flexible ureteroscope, and 12 with a semi-rigid ureteroscope. Three urologists ranked Moses technology as much better or better in 17 procedures. In 2 cases, it was ranked equivalent, and in 4 cases ranking was not done. Overall, laser lithotripsy with Moses technology utilized laser energy in less time to achieve a satisfying stone fragmentation rate of 95.8 mm3/min versus 58.1 mm3/min, P=0.19. However, this did not reach statistical significance. Conclusion The new Moses laser technology demonstrated good stone fragmentation capabilities when used in everyday clinical practice.

  17. Comparison of Surgical Outcomes Between Holmium Laser Enucleation and Transurethral Resection of the Prostate in Patients With Detrusor Underactivity

    Directory of Open Access Journals (Sweden)

    Myeong Jin Woo

    2017-03-01

    Full Text Available Purpose Currently, holmium laser enucleation of the prostate (HoLEP and transurethral resection of the prostate (TURP are the standard surgical procedures used to treat benign prostatic hyperplasia (BPH. Several recent studies have demonstrated that the surgical management of BPH in patients with detrusor underactivity (DU can effectively improve voiding symptoms, but comparative data on the efficacy of HoLEP and TURP are insufficient. Therefore, we compared the short-term surgical outcomes of HoLEP and TURP in patients with DU. Methods From January 2010 to May 2015, 352 patients underwent HoLEP or TURP in procedures performed by a single surgeon. Of these patients, 56 patients with both BPH and DU were enrolled in this study (HoLEP, n=24; TURP, n=32. Surgical outcomes were retrospectively compared between the 2 groups. DU was defined as a detrusor pressure at maximal flow rate of <40 cm H2O as measured by a pressure flow study. Results The preoperative characteristics of patients and the presence of comorbidities were comparable between the 2 groups. The TURP group showed a significantly shorter operative time than the HoLEP group (P=0.033. The weight of the resected prostate was greater in the HoLEP group, and postoperative voiding parameters, including peak flow rate and postvoid residual urine volume were significantly better in the HoLEP group than in the TURP group. Conclusions HoLEP can be effectively and safely performed in patients with DU and can be expected to have better surgical outcomes than TURP in terms of the improvement in lower urinary tract symptoms.

  18. Serial Changes in Sexual Function Following Holmium Laser Enucleation of the Prostate: A Short-term Follow-up Study.

    Science.gov (United States)

    Jeong, Min Su; Ha, Seung Beom; Lee, Chang Ju; Cho, Min Chul; Kim, Soo Woong; Paick, Jae-Seung

    2012-02-01

    To evaluate the serial changes in sexual function in the short-term period after holmium laser enucleation of the prostate (HoLEP) for benign prostatic hyperplasia (BPH) and to investigate whether a change in each domain of the International Index of Erectile Function (IIEF) is associated with improvement of micturition. Thirty-eight potent men who underwent HoLEP and in whom complete 12-month follow-up data on the IIEF were available were included in this retrospective study. All patients underwent a baseline evaluation for BPH. The surgical outcome was evaluated at 1, 3, 6, and 12 months postoperatively by use of the International Prostate Symptom Score, IIEF, and uroflowmetry. The mean age and body mass index of the patients was 64.5±6.2 years and 24.2±2.6 kg/m(2), respectively. Mean total prostate volume and transitional zone volume were 48.8±18.8 ml and 24.2±16.1 ml, respectively. Most IIEF domain scores showed a slight decrease at 1, 3, and 6 months after surgery but recovered to the baseline or showed a marginal but nonsignificant increase at 12 months postoperatively compared with baseline. Orgasmic function and the overall sexual satisfaction domain score remained slightly reduced up to 12 months postoperatively. There was no significant correlation between improvement of micturition and change in sexual function throughout the follow-up period after surgery. Although HoLEP achieves significant improvements in micturition, overall sexual function decreases slightly in the early postoperative period, but recovers to the baseline at 12 months postoperatively. Our data suggest that changes in sexual function after HoLEP are not associated with improvement of micturition.

  19. Expanding rare-earth oxidation state chemistry to molecular complexes of holmium(II) and erbium(II).

    Science.gov (United States)

    MacDonald, Matthew R; Bates, Jefferson E; Fieser, Megan E; Ziller, Joseph W; Furche, Filipp; Evans, William J

    2012-05-23

    The first molecular complexes of holmium and erbium in the +2 oxidation state have been generated by reducing Cp'(3)Ln [Cp' = C(5)H(4)SiMe(3); Ln = Ho (1), Er (2)] with KC(8) in the presence of 18-crown-6 in Et(2)O at -35 °C under argon. Purification and crystallization below -35 °C gave isomorphous [(18-crown-6)K][Cp'(3)Ln] [Ln = Ho (3), Er (4)]. The three Cp' ring centroids define a trigonal-planar geometry around each metal ion that is not perturbed by the location of the potassium crown cation near one ring with K-C(Cp') distances of 3.053(8)-3.078(2) Å. The metrical parameters of the three rings are indistinguishable within the error limits. In contrast to Ln(2+) complexes of Eu, Yb, Sm, Tm, Dy, and Nd, 3 and 4 have average Ln-(Cp' ring centroid) distances only 0.029 and 0.021 Å longer than those of the Ln(3+) analogues 1 and 2, a result similar to that previously reported for the 4d(1) Y(2+) complex [(18-crown-6)K][Cp'(3)Y] (5) and the 5d(1) La(2+) complex [K(18-crown-6)(Et(2)O)][Cp″(3)La] [Cp″ = 1,3-(Me(3)Si)(2)C(5)H(3)]. Surprisingly, the UV-vis spectra of 3 and 4 are also very similar to that of 5 with two broad absorptions in the visible region, suggesting that 3-5 have similar electron configurations. Density functional theory calculations on the Ho(2+) and Er(2+) species yielded HOMOs that are largely 5d(z(2)) in character and supportive of 4f(10)5d(1) and 4f(11)5d(1) ground-state configurations, respectively.

  20. Enucleation ratio efficacy might be a better predictor to assess learning curve of holmium laser enucleation of the prostate

    Directory of Open Access Journals (Sweden)

    Chang Wook Jeong

    2012-06-01

    Full Text Available PURPOSE: To appraise the evaluation methods for learning curve and to analyze the non-mentor-aided learning curve and early complications following the holmium laser enucleation of the prostate. MATERIALS AND METHODS:One-hundred and forty (n=140 consecutive patients who underwent HoLEP from July 2008 to July 2010 by a single surgeon (SJO were enrolled. Perioperative clinical variables, including enucleation time, morcellation time, enucleation ratio (enucleation weight/transitional zone volume, enucleation efficacy (enucleated weight/enucleation time, enucleation ratio efficacy (enucleation ratio/enucleation time, and early complication rate were analyzed. RESULTS: Mean prostate volume was 62.7 mL (range 21-162 and preoperative International Prostate Symptom Score (IPSS was 19.0 (4-35. Mean enucleation time and morcellation time were 49.9±23.8 (S.D. min and 11.0±9.7 min, respectively. Median duration of postoperative indwelling catheter was 1 (1-7 day and median hospital stay was 1 (1-6 day. There were a total of 31 surgery-related complications in 27 patients (19.3%, and all were manageable. There was an increasing trend of enucleation efficacy in the first 50 cases. However, enucleation efficacy was linearly correlated with the prostate size (correlation coefficients, R=0.701, p<0.001. But, enucleation ratio efficacy could eliminate the confounding effect of the prostate size (R=-0.101, p=0.233. The plateau of enucleation ratio efficacy was reached around the twenty-fifth case. CONCLUSIONS: Our results demonstrated that the operative learning curve plateau is reached after about 25 cases. We propose that a more appropriate parameter for estimating the operative learning curve is enucleation ratio efficacy, rather than enucleation efficacy.

  1. Activity coefficients in (hydrogen chloride+holmium chloride) (aq) from T=(278.15 to 328.15) K

    International Nuclear Information System (INIS)

    Roy, Rabindra N.; Roy, Lakshmi N.; Tabor, Bennett J.; Richards, Sarah J.; Cummins, Mason P.; Himes, Curtis A.; Gibbs, Stephanie N.; Christiansen, Edward B.

    2005-01-01

    Activity coefficients of HCl in (hydrogen chloride+holmium chloride) (aq) have been calculated from the observed e.m.f.s using the Nernst equation. The temperatures ranged from (278.15 to 328.15) K at 5 K intervals and at constant total ionic strengths of (0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, and 1.5) mol.kg -1 . Electromotive-force measurements were made on the cell without liquid junction of the type:Pt vertical bar H 2 (g,p=101.325kPa) vertical bar HCl(m A ),HoCl 3 (m B ) vertical bar AgCl(s), vertical bar Ag(s) The results of the activity coefficients of HCl for this mixed electrolyte mixture have been interpreted in terms of the simpler Harned's equations and the ion-interaction model of Pitzer. Results show that the quadratic term is sufficient for the full range of Y B (the ionic strength fraction of the salt) to 0.9 at all the ionic strengths studied. The Pitzer's mixing parameters S θH,Ho and Ψ H,Ho,Cl (including higher order electrostatic effects) and θ H,Ho and Ψ H,Ho,Cl (excluding higher order electrostatic effects) have been determined. These values at T=298.15 K are: S θH , Ho =0.115, Ψ H,Ho,Cl =-.071; and θ H,Ho =-.663, Ψ H,Ho,Cl =0.165. The parameters obtained in this study reproduce the activity coefficients of HCl in the mixtures within 0.015 over the entire range of ionic strengths and within 0.009 for I>=0.05 mol.kg -1 over the entire temperature range

  2. Continuous-wave ceramic Nd:YAG laser at 1123 nm

    International Nuclear Information System (INIS)

    Zhang, S S; Wang, Q P; Zhang, X Y; Cong, Z H; Fan, S Z; Liu, Z J; Sun, W J

    2009-01-01

    Ceramic Nd:YAG (cNd:YAG) materials are employed to generate 1123-nm laser. A fiber-coupled continuous-wave (CW) 808-nm diode laser is used as the pumping source. With an incident diode power of 26.1 W, a CW output power of up to 10.8 W is obtained with a 10-mm-long ceramic Nd:YAG rod (1.0 at.%-Nd-doped). The conversion efficiency from diode power to 1123-nm laser power is 41.4%. The laser performance of another 10-mm-long cNd:YAG rod with a Nd-doping concentration of 0.6 at.% is studied as a comparison

  3. Continuous production of phosphor YAG:Tb nanoparticles by hydrothermal synthesis in supercritical water

    International Nuclear Information System (INIS)

    Hakuta, Yukiya; Haganuma, Tsukasa; Sue, Kiwamu; Adschiri, Tadafumi; Arai, Kunio

    2003-01-01

    Phosphor YAG:Tb ((Y 2.7 Tb 0.3 )Al 5 O 12 ) nano particles were synthesized by a hydrothermal method at supercritical conditions (400 deg. C and 30 MPa) using a flow reactor. Hydroxide sol solutions formed by stoichiometric aluminum nitrate, yttrium nitrate, terbium nitrate and potassium hydroxide solutions. The relationship between particle size and experimental variables including pH, concentration of coexistent ions and hydroxide sol were investigated. Particles were characterized by XRD, TEM and photo-luminescence measurements. Particle size of YAG:Tb became finer as pH was increased or potassium nitrate concentration of the starting metal salt solution was increased. By removing the coexisting ions (NO 3 - , K + ) from the metal salt solution, single phase YAG:Tb particles with 20 nm particle size were obtained. The emission spectra of YAG:Tb particles of 14 nm shows a blue shift

  4. Luminescence and scintillation properties of YAG:Ce single crystal and optical ceramics

    CERN Document Server

    Mihóková, E; Mareš, J A; Beitlerová, A; Vedda, A; Nejezchleb, K; Blažek, K; D’Ambrosio, C

    2007-01-01

    We use various techniques to study optical and scintillation properties of Ce-doped yttrium aluminum garnet, Y3Al5O12 (YAG:Ce), in the form of a high-quality industrial single crystal. This was compared to optical ceramics prepared from YAG:Ce nanopowders. We present experimental data in the areas of optical absorption, radioluminescence, scintillation decay, photoelectron yield, thermally stimulated luminescence and radiation-induced absorption. The results point to an interesting feature—the absence of antisite (YAl, i.e. Y at the Al site) defects in optical ceramics. The scintillation decay of the ceramics is faster than that of the single crystal, but its photoelectron yield (measured with 1 μs integration time) is about 30–40% lower. Apart from the photoelectron yield value the YAG:Ce optical ceramic is fully comparable to a high quality industrial YAG:Ce single crystal and can become a competitive scintillator material.

  5. Diode pumped 1kHz high power Nd:YAG laser with excellent beam quality

    NARCIS (Netherlands)

    Godfried, Herman; Godfried, H.P; Offerhaus, Herman L.

    1997-01-01

    The design and operation of a one kilohertz diode pumped all solid-state Nd:YAG master oscillator power amplifier system with a phase conjugate mirror is presented. The setup allows high power scaling without reduction in beam quality.

  6. High energy single frequency Yb:YAG crystalline fiber waveguide master oscillator power amplifier, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective is to demonstrate the concept of Yb:YAG crystalline fiber MOPA laser and investigation the technical feasibility toward 50 mJ single frequency...

  7. Simultaneous synthesis and densification of transparent, photoluminescent polycrystalline YAG by current activated pressure assisted densification (CAPAD)

    Energy Technology Data Exchange (ETDEWEB)

    Penilla, E.H.; Kodera, Y. [Mechanical Engineering Dept., Materials Science and Engineering Program, University of California, Riverside (United States); Garay, J.E., E-mail: jegaray@engr.ucr.edu [Mechanical Engineering Dept., Materials Science and Engineering Program, University of California, Riverside (United States)

    2012-08-20

    Highlights: Black-Right-Pointing-Pointer We report a method for the synthesis of transparent and PL bulk polycrystalline Ce:YAG using CAPAD. Black-Right-Pointing-Pointer The process uses {gamma}-Al{sub 2}O{sub 3}, Y{sub 2}O{sub 3}, and CeO{sub 2} nanopowders, reacted and densified simultaneously. Black-Right-Pointing-Pointer The synthesis/densification kinetics are faster than those reported previously. Black-Right-Pointing-Pointer Optical measurements show good transparency in the visible and photoluminescence (PL) in the Ce:YAG. Black-Right-Pointing-Pointer The PL peak is broad and appears white when excited using blue light. - Abstract: We report a method for the synthesis and processing of transparent bulk polycrystalline yttrium aluminum garnet (YAG) and photoluminescent Ce-doped YAG ceramics via solid-state reactive-current activated pressure assisted densification (CAPAD). The process uses commercially available {gamma}-Al{sub 2}O{sub 3}, Y{sub 2}O{sub 3}, and CeO{sub 2} nanopowders. The nanopowders were reacted and densified simultaneously at temperatures between 850 Degree-Sign C and 1550 Degree-Sign C and at a maximum pressure of 105 MPa. The solid-state reaction to phase pure YAG occurs in under 4 min at processing temperatures 1100 Degree-Sign C which is significantly faster (on the order of tens of hours) and occurs at much lower temperatures ({approx}600 Degree-Sign C) compared to conventional reaction sintering. We found that the reaction significantly improves densification - the shrinkage rate of reaction-produced YAG was three times higher than that of YAG using pre-reacted powder. The Ce additions were found to retard the reaction driven shrinkage kinetics by a factor {approx}3, but are still faster (by a factor {approx}1.6) than those associated with direct densification (no synthesis). Densities >99% were achieved in both pure YAG and Ce doped YAG (Ce:YAG). Results of optical measurements show good transparency in the visible and

  8. Simultaneous synthesis and densification of transparent, photoluminescent polycrystalline YAG by current activated pressure assisted densification (CAPAD)

    International Nuclear Information System (INIS)

    Penilla, E.H.; Kodera, Y.; Garay, J.E.

    2012-01-01

    Highlights: ► We report a method for the synthesis of transparent and PL bulk polycrystalline Ce:YAG using CAPAD. ► The process uses γ-Al 2 O 3 , Y 2 O 3 , and CeO 2 nanopowders, reacted and densified simultaneously. ► The synthesis/densification kinetics are faster than those reported previously. ► Optical measurements show good transparency in the visible and photoluminescence (PL) in the Ce:YAG. ► The PL peak is broad and appears white when excited using blue light. - Abstract: We report a method for the synthesis and processing of transparent bulk polycrystalline yttrium aluminum garnet (YAG) and photoluminescent Ce-doped YAG ceramics via solid-state reactive-current activated pressure assisted densification (CAPAD). The process uses commercially available γ-Al 2 O 3 , Y 2 O 3 , and CeO 2 nanopowders. The nanopowders were reacted and densified simultaneously at temperatures between 850 °C and 1550 °C and at a maximum pressure of 105 MPa. The solid-state reaction to phase pure YAG occurs in under 4 min at processing temperatures 1100 °C which is significantly faster (on the order of tens of hours) and occurs at much lower temperatures (∼600 °C) compared to conventional reaction sintering. We found that the reaction significantly improves densification – the shrinkage rate of reaction-produced YAG was three times higher than that of YAG using pre-reacted powder. The Ce additions were found to retard the reaction driven shrinkage kinetics by a factor ∼3, but are still faster (by a factor ∼1.6) than those associated with direct densification (no synthesis). Densities >99% were achieved in both pure YAG and Ce doped YAG (Ce:YAG). Results of optical measurements show good transparency in the visible and photoluminescence (PL) in the Ce:YAG. The PL peak is broad and appears white when excited using blue light confirming that the ceramics can be used in solid state lighting to produce white light.

  9. Influence of Gamma-Ray Irradiation on Absorption and Fluorescent Spectra of Nd:YAG and Yb:YAG Laser Crystals

    Institute of Scientific and Technical Information of China (English)

    SUN Dun-Lu; ZHANG Qing-Li; XIAO Jing-Zhong; LUO Jian-Qiao; JIANG Hai-He; YIN Shao-Tang

    2008-01-01

    We investigate the influence of gamma-ray irradiation on the absorption and fluorescent spectra of Nd3+ : Y3Al5O12 (Nd:YAG) and Yb3+ :Y3Al5O12 (Yb:YAG) crystals grown by the Czochralski method. Two additional absorption (AA) bands induced by gamma-ray irradiation appear at 255nm and 340nm. The former is eontributed due to Fe3+ impurity, the latter is due to Fe2+ ions and F-type colour centres. The intensity of the excitation and emission spectra as well as the fluorescent lifetime of Nd:YAG crystal decrease after the irradiation of 100 Mrad gamma-ray. In contrast, the same dose irradiation does not impair the fluorescent properties of Yb: YA G crystal. These results indicate that Yb: YA G crystal possesses the advantage over Nd: YA G crystal that has better reliability for applications in harsh radiant environment.

  10. Q-switched pulse laser generation from double-cladding Nd:YAG ceramics waveguides.

    Science.gov (United States)

    Tan, Yang; Luan, Qingfang; Liu, Fengqin; Chen, Feng; Vázquez de Aldana, Javier Rodríguez

    2013-08-12

    This work reports on the Q-switched pulsed laser generation from double-cladding Nd:YAG ceramic waveguides. Double-cladding waveguides with different combination of diameters were inscribed into a sample of Nd:YAG ceramic. With an additional semiconductor saturable absorber, stable pulsed laser emission at the wavelength of 1064 nm was achieved with pulses of 21 ns temporal duration and ~14 μJ pulse energy at a repetition rate of 3.65 MHz.

  11. Combination of CO2 and Q-switched Nd:YAG lasers is more effective than Q-switched Nd:YAG laser alone for eyebrow tattoo removal.

    Science.gov (United States)

    Radmanesh, Mohammad; Rafiei, Zohreh

    2015-04-01

    The eyebrow tattoo removal using Q-switched lasers is usually prolonged. Other modalities may be required to enhance the efficacy and shorten the treatment course. To compare the efficacy of Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG) laser alone versus combination of Q-switched Nd:YAG and Ultrapulse CO2 lasers for eyebrow tattoo removal after a single session. After local anesthesia, the right eyebrow of 20 patients was treated with Ultrapulse CO2 laser with the parameters of 4 J/cm(2) and 3.2 J/cm(2) for the first and the second passes. Both eyebrows were then treated with 1064-nm and 532-nm Q-switched Nd:YAG laser. The spot size and pulse duration were 3 mm and 5 nanoseconds for both wavelengths, and the fluence was 7 J/cm(2) for 1064 nm and 3 J/cm (2) for 532 nm. The side treated with combination of Q-switched Nd:YAG and CO2 lasers improved 75-100% in 6 of 20 patients versus only 1 of 20 in the side treated with Q-switched Nd:YAG alone. Similarly, the right side in 13 of 20 patients showed more than 50% improvement with combination therapy versus the left side (the monotherapy side), where only 6 of 20 cases showed more than 50% improvement. The Mann-Whitney test was 2.85 for the right side and 1.95 for the left side (P value = 0.007). Using Ultra pulse CO2 laser enhances the efficacy of Q-switched Nd:YAG laser in eyebrow tattoo removal.

  12. Comparison of central corneal thickness with four noncontact devices: An agreement analysis of swept-source technology

    OpenAIRE

    Erhan Ozyol; Pelin Özyol

    2017-01-01

    Purpose: The purpose of this study was to compare the central corneal thickness (CCT) measurements of four noncontact devices in healthy eyes. Materials and Methods: In a sample of 45 healthy controls, CCT was measured using an optical biometer (IOLMaster 700) based on swept-source optical coherence tomography (SS-OCT), high-resolution rotating Scheimpflug camera system (Pentacam HR), spectral-domain OCT (SD-OCT) device with an anterior segment module (Spectralis), and noncontact pachymetry (...

  13. Er:YAG Laser Dental Treatment of Patients Affected by Epidermolysis Bullosa

    Directory of Open Access Journals (Sweden)

    Angela Galeotti

    2014-01-01

    Full Text Available Aim. The purpose of this study was to evaluate the efficacy of Er:YAG laser used for treating hard dental tissue in patients with epidermolysis bullosa (EB. Methods. We report two cases of EB in which an Er:YAG laser was used for conservative treatments. In the first case, the Er:YAG laser (2,940 μm, 265 mJ, 25 Hz was used to treat caries on a deciduous maxillary canine in an 8-year-old male patient affected by dystrophic EB. In the second case, we treated a 26-year-old female patient, affected by junctional EB, with generalized enamel hypoplasia, and an Er:YAG laser (2,940 μm, 265 mJ, 25 Hz was used to remove the damaged enamel on maxillary incisors. Results. The use of the Er:YAG laser, with the appropriate energy, was effective in the selective removal of carious tissue and enamel hypoplasia. During dental treatment with the Er:YAG laser, patients required only a few interruptions due to the absence of pain, vibration, and noise. Conclusions. Laser treatment of hard dental tissues is a valuable choice for patients affected by EB since it is less invasive compared to conventional treatment, resulting in improved patient compliance.

  14. 10-kW-class YAG laser application for heavy components

    Science.gov (United States)

    Ishide, Takashi; Tsubota, S.; Nayama, Michisuke; Shimokusu, Yoshiaki; Nagashima, Tadashi; Okimura, K.

    2000-02-01

    The authors have put the YAG laser of the kW class to practical use for repair welding of nuclear power plant steam generator heat exchanger tubes, all-position welding of pipings, etc. This paper describes following developed methods and systems of high power YAG laser processing. First, we apply the 6 kW to 10 kW YAG lasers for welding and cutting in heavy components. The beam guide systems we have used are optical fibers which core diameter is 0.6 mm to 0.8 mm and its length is 200 m as standard one. Using these system, we can get the 1 pass penetration of 15 mm to 20 mm and multi pass welding for more thick plates. Cutting of 100 mm thickness plate data also described for dismantling of nuclear power plants. In these systems we carried out the in-process monitoring by using CCD camera image processing and monitoring fiber which placed coaxial to the YAG optical lens system. In- process monitoring by the monitoring fiber, we measured the light intensity from welding area. Further, we have developed new hybrid welding with the TIG electrode at the center of lens for high power. The hybrid welding with TIG-YAG system aims lightening of welding groove allowances and welding of high quality. Through these techniques we have applied 7 kW class YAG laser for welding in the components of nuclear power plants.

  15. Determination of the compressive yield strength for nano-grained YAG transparent ceramic by XRD analysis

    International Nuclear Information System (INIS)

    Wang, H.M.; Jiang, J.S.; Huang, Z.Y.; Chen, Y.; Liu, K.; Lu, Z.W.; Qi, J.Q.; Li, F.; He, D.W.; Lu, T.C.; Wang, Q.Y.

    2016-01-01

    Nano-grained ceramics have their unique mechanical characteristics that are not commonly found in their coarse-grained counterparts. In this study, nano-grained YAG transparent ceramics (NG-YAG) were prepared by low-temperature high-pressure technique (LTHP). The peak profile analysis of the X-ray diffraction was employed to investigate the compressive yield strength of NG-YAG. During the temperature at 450 °C, the residual micro-strain (RMS) increased with increasing loading pressure. However when the loading pressure was exceeded to 4.0 GPa the RMS exhibited a severe negative slop. The temperature effects on the compressive yield strength were also studied. It shows that the compressive yield strength of NG-YAG is 4.0 GPa and 5.0 GPa respectively at 450 °C and 350 °C. More importantly according to this investigation, a feasible technique to study the nano-grained ceramics is provided. - Graphical abstract: Fig. 2 shows the significant slope changes of calculated residual micro-strain (RMS) associated with five selected pressure-temperature conditions. Another the grain size estimated from Scherrer's formula, especially when it changes with the pressure-temperature condition is also plotted in Fig. 2. - Highlights: • Prepared the nano-grained YAG transparent ceramic by high pressure technique. • Obtained the compressive yield with different temperature. • Obtained the compressive yield of nano-grained YAG transparent ceramic.

  16. Co-precipitation synthesis of YAG:Dy nanophosphor and its thermometric properties

    International Nuclear Information System (INIS)

    Chong, Joo-Yun; Zhang, Yuelan; Wagner, Brent K.; Kang, Zhitao

    2013-01-01

    Highlights: •YAG:Dy nanophosphors were synthesized with particle size of about 50 nm. •Optimized doping concentration of 6%Dy was determined. •Thermometric photoluminescence properties were studied between 20 and 350 °C. •Temperature-sensitive change in peak ratio of 496/457 nm emissions was demonstrated. •Suitable for potential thermographic applications when dispersed in a liquid media. -- Abstract: Dy 3+ doped yttrium aluminum garnet (YAG) nanophosphors were synthesized by a co-precipitation method for potential thermographic applications in a liquid media dispersed with fluorescent nanoparticles. The doping concentration and annealing temperature on the structural and optical properties of YAG:Dy were investigated. Pure phase YAG:Dy nanophosphors were obtained by annealing the co-precipitated hydroxide products at above 900 °C. Maximum photoluminescence intensity was observed from 6%Dy doped YAG samples. The effect of measuring temperature between 20 and 350 °C on the photoluminescence spectra of nano YAG:Dy was investigated. A temperature-sensitive change in the peak intensity ratio of 496/457 nm emission lines was demonstrated for such nanophosphors for the first time, suggesting potential applications in temperature monitoring of fuel spray

  17. Co-precipitation synthesis of YAG:Dy nanophosphor and its thermometric properties

    Energy Technology Data Exchange (ETDEWEB)

    Chong, Joo-Yun [School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Zhang, Yuelan [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Wagner, Brent K. [Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Kang, Zhitao, E-mail: zhitao.kang@gtri.gatech.edu [Georgia Tech Research Institute, Georgia Institute of Technology, Atlanta, GA 30332 (United States); School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

    2013-12-25

    Highlights: •YAG:Dy nanophosphors were synthesized with particle size of about 50 nm. •Optimized doping concentration of 6%Dy was determined. •Thermometric photoluminescence properties were studied between 20 and 350 °C. •Temperature-sensitive change in peak ratio of 496/457 nm emissions was demonstrated. •Suitable for potential thermographic applications when dispersed in a liquid media. -- Abstract: Dy{sup 3+} doped yttrium aluminum garnet (YAG) nanophosphors were synthesized by a co-precipitation method for potential thermographic applications in a liquid media dispersed with fluorescent nanoparticles. The doping concentration and annealing temperature on the structural and optical properties of YAG:Dy were investigated. Pure phase YAG:Dy nanophosphors were obtained by annealing the co-precipitated hydroxide products at above 900 °C. Maximum photoluminescence intensity was observed from 6%Dy doped YAG samples. The effect of measuring temperature between 20 and 350 °C on the photoluminescence spectra of nano YAG:Dy was investigated. A temperature-sensitive change in the peak intensity ratio of 496/457 nm emission lines was demonstrated for such nanophosphors for the first time, suggesting potential applications in temperature monitoring of fuel spray.

  18. A rapid tattoo removal technique using a combination of pulsed Er:YAG and Q-Switched Nd:YAG in a split lesion protocol.

    Science.gov (United States)

    Sardana, Kabir; Ranjan, Rashmi; Kochhar, Atul M; Mahajan, Khushbu Goel; Garg, Vijay K

    2015-01-01

    Tattoo removal has evolved over the years and though Q-switched laser is the 'workhorse' laser, it invariably requires multiple sittings, which are dependent on numerous factors, including the skin colour, location of the tattoo, age of the tattoo, colour of pigment used, associated fibrosis and the kind of tattoo treated. Though ablative lasers, both pulsed CO2 and Er:YAG, have been used for recalcitrant tattoos, very few studies have been done comparing them with pigment-specific lasers. Our study was based on the premise that ablating the epidermis overlying the tattoo pigment with Er:YAG could help in gaining better access to the pigment which would enable the Q-switched laser to work effectively with less beam scattering. A study of rapid tattoo removal (RTR) technique using a combination of pulsed Er:YAG and Q-Switched Nd:YAG in a split lesion protocol. This prospective study was undertaken during 2010-13 at a laser Clinic in the Maulana Azad Medical College, New Delhi. A total of 10 patients were recruited, 5 of amateur tattoo and 5 of professional tattoo. After informed consent each tattoo was arbitrarily 'split' into two parts. One part was treated with QS Nd:YAG laser(1064 nm) and the other part with Er:YAG laser immediately followed by the QS Nd:YAG. The laser treatments were repeated at 6-week intervals until the tattoo pigment had cleared. On the combination side in subsequent sittings only the QS Nd:YAG was used, to minimize repetitive ablation. To ensure consistency in the intervention methods a trained dermatologist who was independent of the treatment delivery randomly rated 10% of the procedures. The mean improvement achieved by the Q-switched laser (2.93) was less than the combination laser (3.85) side (p = 0.001) and needed more sessions (3.8 vs. 1.6; p = 0.001). There was a statistically significant difference in the improvement on the combination side till the second session. On the combination side patients required a maximum of 2 sessions

  19. Marginal microleakage in vitro study on class V cavities prepared with Er:YAG laser and etched with acid or etched with Er:YAG laser and acid

    International Nuclear Information System (INIS)

    Tavares, Henrique Dutra Simoes

    2001-01-01

    Microleakage at the interface between the teeth and the restorative materials remains a problem with composite resin restorations. Microleakage at the gingival margins of class V cavities restorations still challenge as they are usually placed in dentin and/or cementum. Previous studies have shown that the cavity preparation with Er:YAG laser is possible. It has been reported that Er:YAG laser has ability to create irregular surface providing micromechanical retention for adhesive dental restorative materials and to improve marginal sealing. The purpose of this in vitro study was to evaluate the marginal microleakage on class V cavities prepared with Er:YAG laser and etched with acid or with Er:YAG laser and acid, in compared to those prepared and etched conventionally. Thirty human molars were divided into three groups, namely: group I - prepared with Er:YAG laser (KaVo KEY Laser II - Germany) and etched with 37% phosphoric acid; group II - prepared with Er:YAG laser and etched with Er:YAG laser and 37% phosphoric acid; group III (control group) - prepared with high speed drill and etched with 37% phosphoric acid. All cavities were treated with same adhesive system (Single Bond - 3M) and restored with the composite resin (Z100 - 3M), according to the manufacturer's instructions. The specimens were stored at 37 deg C in water for 24 hours, polished with Sof-Lex discs (3M), thermally stressed, sealed with a nail polish coating except for the area of the restoration and 1 mm around it, and immersed in a 50% aqueous solution of silver nitrate for 24 hours. After that, the specimens were rinsed in water, soaked in a photodeveloping solution and exposed to a fluorescent light for 8 hours. The teeth were embedded in an autopolymerizing resin and sectioned longitudinally using a diamond saw microtome under running water. The sections were photographed. The microleakage at the occlusal cavity and at the gingival margins of each specimen was evaluated with scores (0-3) by

  20. Non-contact translation-rotation sensor using combined effects of magnetostriction and piezoelectricity.

    Science.gov (United States)

    Yang, Bintang; Liu, Qingwei; Zhang, Ting; Cao, Yudong; Feng, Zhiqiang; Meng, Guang

    2012-10-15

    Precise displacement sensors are an important topic in precision engineering. At present, this type of sensors typically have a single feature of either translation or rotation measurement. They are also inconvenient to integrate with the host devices. In this report we propose a new kind of sensor that enables both translation and rotation measurement by using the combined effect of magnetostriction and piezoelectricity. As a proof of concept, we experimentally realized a prototype of non-contact translation-rotation precise sensor. In the current research stage, through both theoretical and experimental study, the non-contact displacement sensor is shown to be feasible for measuring both translation and rotation either in coarse or fine measurement. Moreover, owing to its compact, rigid structure and fewer components, it can be easily embedded in host equipment.

  1. Non-Contact Translation-Rotation Sensor Using Combined Effects of Magnetostriction and Piezoelectricity

    Directory of Open Access Journals (Sweden)

    Guang Meng

    2012-10-01

    Full Text Available Precise displacement sensors are an important topic in precision engineering. At present, this type of sensors typically have a single feature of either translation or rotation measurement. They are also inconvenient to integrate with the host devices. In this report we propose a new kind of sensor that enables both translation and rotation measurement by using the combined effect of magnetostriction and piezoelectricity. As a proof of concept, we experimentally realized a prototype of non-contact translation-rotation precise sensor. In the current research stage, through both theoretical and experimental study, the non-contact displacement sensor is shown to be feasible for measuring both translation and rotation either in coarse or fine measurement. Moreover, owing to its compact, rigid structure and fewer components, it can be easily embedded in host equipment.

  2. Development of an Image Colorimeter for Noncontact Skin Color Measurement and Application to the Dermatological Treatment

    Science.gov (United States)

    Akimoto, Makio; Chen, Yu; Miyazaki, Michio; Yamashita, Toyonobu; Miyakawa, Michio; Hata, Mieko

    The skin is unique as an organ that is highly accessible to direct visual inspection with light. Visual inspection of cutaneous morphology is the mainstay of clinical dermatology, but relies heavily on subjective assessment by the skilled dermatologists. We present an imaging colorimeter of non-contact skin color measuring system and some experimented results using such instrument. The system is comprised by a video camera, light source, a real-time image processing board, magneto optics disk and personal computer which controls the entire system. The CIE-L*a*b* uniform color space is used. This system is used for monitoring of some clinical diagnosis. The instrument is non-contact, easy to operate, and has a high precision unlike the conventional colorimeters. This instrument is useful for clinical diagnoses, monitoring and evaluating the effectiveness of treatment.

  3. Acanthamoeba keratitis in a non-contact lens wearer with human immunodeficiency virus

    DEFF Research Database (Denmark)

    Hansen, Birgitte Rønde; Kronborg, Gitte

    2003-01-01

    Acanthamoeba keratitis is potentially blinding and often associated with contact lens wearing. A human immunodeficiency virus (HIV)-positive patient, a non-contact lens wearer, presented with keratitis. She experienced a protracted course of disease, characterized by exacerbations and remissions......, and was treated with various topical antibiotics and steroids. 13 months after symptom onset the eye was removed owing to serious scarring of cornea and unbearable pain. Microbiological and histopathological examination of the cornea showed Acanthamoeba. In non-contact lens wearers suffering from Acanthamoeba...... keratitis the diagnosis is delayed, pathognomonic features are often not seen and visual outcome is usually poor. There is no known relation between HIV infection and Acanthamoeba keratitis....

  4. Secondary seal effects in hydrostatic non-contact seals for reactor coolant pump shaft

    International Nuclear Information System (INIS)

    Fujita, T.; Koga, T.; Tanoue, H.; Hirabayashi, H.

    1987-01-01

    The paper presents a seal flow analysis in a hydrostatic non-contact seal for a PWR coolant pump shaft. A description is given of the non-contact seal for the reactor coolant pump. Results are presented for a distortion analysis of the seal ring, along with the seal flow characteristics and the contact pressure profiles of the secondary seals. The results of the work confirm previously reported findings that the seal ring distortion is sensitive to the o-ring location (which was placed between the ceramic seal face and the seal ring retainer). The paper concludes that the seal flow characteristics and the tracking performance depend upon the dynamic properties of the secondary seal. (U.K.)

  5. Contact and non-contact ultrasonic measurement in the food industry: a review

    International Nuclear Information System (INIS)

    Mohd Khairi, Mohd Taufiq; Ibrahim, Sallehuddin; Md Yunus, Mohd Amri; Faramarzi, Mahdi

    2016-01-01

    The monitoring of the food manufacturing process is vital since it determines the safety and quality level of foods which directly affect the consumers’ health. Companies which produce high quality products will gain trust from consumers. This factor helps the companies to make profits. The use of efficient and appropriate sensors for the monitoring process can also reduce cost. The food assessing process based on an ultrasonic sensor has attracted the attention of the food industry due to its excellent capabilities in several applications. The utilization of low or high frequencies for the ultrasonic transducer has provided an enormous benefit for analysing, modifying and guaranteeing the quality of food. The contact and non-contact ultrasonic modes for measurement also contributed significantly to the food processing. This paper presents a review of the application of the contact and non-contact mode of ultrasonic measurement focusing on safety and quality control areas. The results from previous researches are shown and elaborated. (topical review)

  6. Contact and non-contact ultrasonic measurement in the food industry: a review

    Science.gov (United States)

    Taufiq Mohd Khairi, Mohd; Ibrahim, Sallehuddin; Yunus, Mohd Amri Md; Faramarzi, Mahdi

    2016-01-01

    The monitoring of the food manufacturing process is vital since it determines the safety and quality level of foods which directly affect the consumers’ health. Companies which produce high quality products will gain trust from consumers. This factor helps the companies to make profits. The use of efficient and appropriate sensors for the monitoring process can also reduce cost. The food assessing process based on an ultrasonic sensor has attracted the attention of the food industry due to its excellent capabilities in several applications. The utilization of low or high frequencies for the ultrasonic transducer has provided an enormous benefit for analysing, modifying and guaranteeing the quality of food. The contact and non-contact ultrasonic modes for measurement also contributed significantly to the food processing. This paper presents a review of the application of the contact and non-contact mode of ultrasonic measurement focusing on safety and quality control areas. The results from previous researches are shown and elaborated.

  7. Coupled biomechanical response of the cornea assessed by non-contact tonometry. A simulation study.

    Directory of Open Access Journals (Sweden)

    Miguel Á Ariza-Gracia

    Full Text Available The mechanical response of the cornea subjected to a non-contact air-jet tonometry diagnostic test represents an interplay between its geometry, the corneal material behavior and the loading. The objective is to study this interplay to better understand and interpret the results obtained with a non-contact tonometry test. A patient-specific finite element model of a healthy eye, accounting for the load free configuration, was used. The corneal tissue was modeled as an anisotropic hyperelastic material with two preferential directions. Three different sets of parameters within the human experimental range obtained from inflation tests were considered. The influence of the IOP was studied by considering four pressure levels (10-28 mmHg whereas the influence of corneal thickness was studied by inducing a uniform variation (300-600 microns. A Computer Fluid Dynamics (CFD air-jet simulation determined pressure loading exerted on the anterior corneal surface. The maximum apex displacement showed a linear variation with IOP for all materials examined. On the contrary, the maximum apex displacement followed a cubic relation with corneal thickness. In addition, a significant sensitivity of the apical displacement to the corneal stiffness was also obtained. Explanation to this behavior was found in the fact that the cornea experiences bending when subjected to an air-puff loading, causing the anterior surface to work in compression whereas the posterior surface works in tension. Hence, collagen fibers located at the anterior surface do not contribute to load bearing. Non-contact tonometry devices give useful information that could be misleading since the corneal deformation is the result of the interaction between the mechanical properties, IOP, and geometry. Therefore, a non-contact tonometry test is not sufficient to evaluate their individual contribution and a complete in-vivo characterization would require more than one test to independently determine

  8. Measurement properties and usability of non-contact scanners for measuring transtibial residual limb volume.

    Science.gov (United States)

    Kofman, Rianne; Beekman, Anna M; Emmelot, Cornelis H; Geertzen, Jan H B; Dijkstra, Pieter U

    2018-06-01

    Non-contact scanners may have potential for measurement of residual limb volume. Different non-contact scanners have been introduced during the last decades. Reliability and usability (practicality and user friendliness) should be assessed before introducing these systems in clinical practice. The aim of this study was to analyze the measurement properties and usability of four non-contact scanners (TT Design, Omega Scanner, BioSculptor Bioscanner, and Rodin4D Scanner). Quasi experimental. Nine (geometric and residual limb) models were measured on two occasions, each consisting of two sessions, thus in total 4 sessions. In each session, four observers used the four systems for volume measurement. Mean for each model, repeatability coefficients for each system, variance components, and their two-way interactions of measurement conditions were calculated. User satisfaction was evaluated with the Post-Study System Usability Questionnaire. Systematic differences between the systems were found in volume measurements. Most of the variances were explained by the model (97%), while error variance was 3%. Measurement system and the interaction between system and model explained 44% of the error variance. Repeatability coefficient of the systems ranged from 0.101 (Omega Scanner) to 0.131 L (Rodin4D). Differences in Post-Study System Usability Questionnaire scores between the systems were small and not significant. The systems were reliable in determining residual limb volume. Measurement systems and the interaction between system and residual limb model explained most of the error variances. The differences in repeatability coefficient and usability between the four CAD/CAM systems were small. Clinical relevance If accurate measurements of residual limb volume are required (in case of research), modern non-contact scanners should be taken in consideration nowadays.

  9. Modeling leukocyte-leukocyte non-contact interactions in a lymph node.

    Science.gov (United States)

    Gritti, Nicola; Caccia, Michele; Sironi, Laura; Collini, Maddalena; D'Alfonso, Laura; Granucci, Francesca; Zanoni, Ivan; Chirico, Giuseppe

    2013-01-01

    The interaction among leukocytes is at the basis of the innate and adaptive immune-response and it is largely ascribed to direct cell-cell contacts. However, the exchange of a number of chemical stimuli (chemokines) allows also non-contact interaction during the immunological response. We want here to evaluate the extent of the effect of the non-contact interactions on the observed leukocyte-leukocyte kinematics and their interaction duration. To this aim we adopt a simplified mean field description inspired by the Keller-Segel chemotaxis model, of which we report an analytical solution suited for slowly varying sources of chemokines. Since our focus is on the non-contact interactions, leukocyte-leukocyte contact interactions are simulated only by means of a space dependent friction coefficient of the cells. The analytical solution of the Keller-Segel model is then taken as the basis of numerical simulations of interactions between leukocytes and their duration. The mean field interaction force that we derive has a time-space separable form and depends on the chemotaxis sensitivity parameter as well as on the chemokines diffusion coefficient and their degradation rate. All these parameters affect the distribution of the interaction durations. We draw a successful qualitative comparison between simulated data and sets of experimental data for DC-NK cells interaction duration and other kinematic parameters. Remarkably, the predicted percentage of the leukocyte-leukocyte interactions falls in the experimental range and depends (~25% increase) upon the chemotactic parameter indicating a non-negligible direct effect of the non-contact interaction on the leukocyte interactions.

  10. Structural, Functional, and Metabolic Brain Markers Differentiate Collision versus Contact and Non-Contact Athletes.

    Science.gov (United States)

    Churchill, Nathan W; Hutchison, Michael G; Di Battista, Alex P; Graham, Simon J; Schweizer, Tom A

    2017-01-01

    There is growing concern about how participation in contact sports affects the brain. Retrospective evidence suggests that contact sports are associated with long-term negative health outcomes. However, much of the research to date has focused on former athletes with significant health problems. Less is known about the health of current athletes in contact and collision sports who have not reported significant medical issues. In this cross-sectional study, advanced magnetic resonance imaging (MRI) was used to evaluate multiple aspects of brain physiology in three groups of athletes participating in non-contact sports ( N  = 20), contact sports ( N  = 22), and collision sports ( N  = 23). Diffusion tensor imaging was used to assess white matter microstructure based on measures of fractional anisotropy (FA) and mean diffusivity (MD); resting-state functional MRI was used to evaluate global functional connectivity; single-voxel spectroscopy was used to compare ratios of neural metabolites, including N -acetyl aspartate (NAA), creatine (Cr), choline, and myo-inositol. Multivariate analysis revealed structural, functional, and metabolic measures that reliably differentiated between sport groups. The collision group had significantly elevated FA and reduced MD in white matter, compared to both contact and non-contact groups. In contrast, the collision group showed significant reductions in functional connectivity and the NAA/Cr metabolite ratio, relative to only the non-contact group, while the contact group overlapped with both non-contact and collision groups. For brain regions associated with contact sport participation, athletes with a history of concussion also showed greater alterations in FA and functional connectivity, indicating a potential cumulative effect of both contact exposure and concussion history on brain physiology. These findings indicate persistent differences in brain physiology for athletes participating in contact and collision sports

  11. Analytical model development of an eddy-current-based non-contacting steel plate conveyance system

    International Nuclear Information System (INIS)

    Liu, C.-T.; Lin, S.-Y.; Yang, Y.-Y.; Hwang, C.-C.

    2008-01-01

    A concise model for analyzing and predicting the quasi-static electromagnetic characteristics of an eddy-current-based non-contacting steel plate conveyance system has been developed. Confirmed by three-dimensional (3-D) finite element analysis (FEA), adequacy of the analytical model can be demonstrated. Such an effective approach, which can be conveniently used by the potential industries for preliminary system operational performance evaluations, will be essential for designers and on-site engineers

  12. Modeling leukocyte-leukocyte non-contact interactions in a lymph node.

    Directory of Open Access Journals (Sweden)

    Nicola Gritti

    Full Text Available The interaction among leukocytes is at the basis of the innate and adaptive immune-response and it is largely ascribed to direct cell-cell contacts. However, the exchange of a number of chemical stimuli (chemokines allows also non-contact interaction during the immunological response. We want here to evaluate the extent of the effect of the non-contact interactions on the observed leukocyte-leukocyte kinematics and their interaction duration. To this aim we adopt a simplified mean field description inspired by the Keller-Segel chemotaxis model, of which we report an analytical solution suited for slowly varying sources of chemokines. Since our focus is on the non-contact interactions, leukocyte-leukocyte contact interactions are simulated only by means of a space dependent friction coefficient of the cells. The analytical solution of the Keller-Segel model is then taken as the basis of numerical simulations of interactions between leukocytes and their duration. The mean field interaction force that we derive has a time-space separable form and depends on the chemotaxis sensitivity parameter as well as on the chemokines diffusion coefficient and their degradation rate. All these parameters affect the distribution of the interaction durations. We draw a successful qualitative comparison between simulated data and sets of experimental data for DC-NK cells interaction duration and other kinematic parameters. Remarkably, the predicted percentage of the leukocyte-leukocyte interactions falls in the experimental range and depends (~25% increase upon the chemotactic parameter indicating a non-negligible direct effect of the non-contact interaction on the leukocyte interactions.

  13. SensInDenT-Noncontact Sensors Integrated Into Dental Treatment Units.

    Science.gov (United States)

    Teichmann, Daniel; Teichmann, Maren; Weitz, Philippe; Wolfart, Stefan; Leonhardt, Steffen; Walter, Marian

    2017-02-01

    This paper presents the first system design (SensInDenT) for noncontact cardiorespiratory monitoring during dental treatment. The system is integrated into a dental treatment unit, and combines sensors based on electromagnetic, optical, and mechanical coupling at different sensor locations. The measurement principles and circuits are described and a system overview is presented. Furthermore, a first proof of concept is provided by taking measurements in healthy volunteers under laboratory conditions.

  14. Measuring Pulse Rate Variability using Long-Range, Non-Contact Imaging Photoplethysmography

    Science.gov (United States)

    2016-08-20

    contains color . 14. ABSTRACT Camera-based measurement of the blood volume pulse via non-contact, imaging photoplethysmography is a very popular approach...ECG) for each window were calculated in beats per minute (bpm). The periodogram method with a Hamming window was used to estimate mean pulse...11 Hz. Independent component analysis (ICA) was then used to decompose the normalized, bandpass-filtered, color -channel signals into independent

  15. Biometric Changes After Trabeculectomy with Contact and Non-contact Biometry.

    Science.gov (United States)

    Alvani, Azam; Pakravan, Mohammad; Esfandiari, Hamed; Yaseri, Mehdi; Yazdani, Shahin; Ghahari, Elham

    2016-02-01

    To compare biometric changes measured with contact and noncontact methods after mitomycin-C-augmented trabeculectomy. In this prospective study, 31 eyes from 31 glaucoma patients scheduled for primary trabeculectomy were enrolled. Biometric parameters including axial length (AL), anterior chamber depth (ACD), and lens thickness (LT) were measured using contact ultrasound biometry (UD-6000 Ultrasonic A/B scanner biometer; Tomey Corporation, Nagoya, Japan) and a noncontact optical biometry device (Lenstar; Haag-Streit AG, Koeniz, Switzerland). Measurements were taken the day before trabeculectomy and then compared with measurements obtained 3 and 6 months after surgery. The AL and ACD were significantly decreased at 3 and 6 months compared with baseline values taken with each biometry method. There was a significant increase in LT measured by the Lenstar device at the 3- and 6-month follow-up. At both the 3- and 6-month follow-up, the mean AL measurement reduction with the Lenstar device was significantly lower than that of the A-scan ultrasound measurements. The mean ACD changes between the two devices were not significantly different. There is a small but significant decrease in the AL and ACD after trabeculectomy as measured with both the contact and noncontact methods. The amount of AL reduction measured is significantly smaller using the noncontact method, making it the preferable method for intraocular lens power calculation for patients who need cataract surgery combined with or after trabeculectomy. The LT measured by the Lenstar device increased significantly after the operation, which can be an early sign of the progression of cataractous changes after trabeculectomy.

  16. A non-contact complete knee dislocation with popliteal artery disruption, a rare martial arts injury

    OpenAIRE

    Viswanath, Y; Rogers, I

    1999-01-01

    Complete knee dislocation is a rare injury and an associated incidence of popliteal artery damage ranges from 16-60% of cases. It occurs commonly in road traffic accidents and in high velocity trauma where significant contact remains as the usual mode of injury. We describe a rare case of non-contact knee dislocation with popliteal artery injury sustained while practising Aikido, a type of martial art. This patient successfully underwent closed reduction of the knee with an emergency vein byp...

  17. Application of percutaneous endoscopic RF/holmium laser lumbar discectomy in the lumbar disc herniation (attach 160 cases reported)

    International Nuclear Information System (INIS)

    Zhao Zhengxu; Hu Tongzhou; He Jun; Jiang Zenghui; Wang Weiqi; Lin Hang

    2010-01-01

    Objective: To evaluate the efficacy of endoscopic discectomy for the lumbar disc herniation and to determine the prognostic factors affecting surgical outcome. Methods: In the group of 160 cases, posterolateral and trans-interlaminar endoscopic Ho: YAG laser and radio frequency-assisted disc excisions were performed under local anesthesia. Results: In 160 patients with post-surgical follow-up period was 15 months on average (7 ∼ 24 months). Based on the MacNab criteria, there were 117 cases in which result was excellent, in 19 cases good, in 12 cases fair, and in 12 cases poor, and successful rate was 85%. Conclusion: Percutaneous endoscopy lumbar discectomy is effective for recurrent disc herniation in the selected. In applies in particular to the traditional open surgery of lumbar disc herniation in patients with recurrent. (authors)

  18. Non-Contact Plant Growth Measurement Method and System Based on Ubiquitous Sensor Network Technologies

    Directory of Open Access Journals (Sweden)

    Intae Ryoo

    2011-04-01

    Full Text Available This paper proposes a non-contact plant growth measurement system using infrared sensors based on the ubiquitous sensor network (USN technology. The proposed system measures plant growth parameters such as the stem radius of plants using real-time non-contact methods, and generates diameter, cross-sectional area and thickening form of plant stems using this measured data. Non-contact sensors have been used not to cause any damage to plants during measurement of the growth parameters. Once the growth parameters are measured, they are transmitted to a remote server using the sensor network technology and analyzed in the application program server. The analyzed data are then provided for administrators and a group of interested users. The proposed plant growth measurement system has been designed and implemented using fixed-type and rotary-type infrared sensor based measurement methods and devices. Finally, the system performance is compared and verified with the measurement data that have been obtained by practical field experiments.

  19. Fully Noncontact Wave Propagation Imaging in an Immersed Metallic Plate with a Crack

    Directory of Open Access Journals (Sweden)

    Jung-Ryul Lee

    2014-01-01

    Full Text Available This study presents a noncontact sensing technique with ultrasonic wave propagation imaging algorithm, for damage visualization of liquid-immersed structures. An aluminum plate specimen (400 mm × 400 mm × 3 mm with a 12 mm slit was immersed in water and in glycerin. A 532 nm Q-switched continuous wave laser is used at an energy level of 1.2 mJ to scan an area of 100 mm × 100 mm. A laser Doppler vibrometer is used as a noncontact ultrasonic sensor, which measures guided wave displacement at a fixed point. The tests are performed with two different cases of specimen: without water and filled with water and with glycerin. Lamb wave dispersion curves for the respective cases are calculated, to investigate the velocity-frequency relationship of each wave mode. Experimental propagation velocities of Lamb waves for different cases are compared with the theoretical dispersion curves. This study shows that the dispersion and attenuation of the Lamb wave is affected by the surrounding liquid, and the comparative experimental results are presented to verify it. In addition, it is demonstrated that the developed fully noncontact ultrasonic propagation imaging system is capable of damage sizing in submerged structures.

  20. An investigation of highly accurate and precise robotic hole measurements using non-contact devices

    Directory of Open Access Journals (Sweden)

    Usman Zahid

    2016-01-01

    Full Text Available Industrial robots arms are widely used in manufacturing industry because of their support for automation. However, in metrology, robots have had limited application due to their insufficient accuracy. Even using error compensation and calibration methods, robots are not effective for micrometre (μm level metrology. Non-contact measurement devices can potentially enable the use of robots for highly accurate metrology. However, the use of such devices on robots has not been investigated. The research work reported in this paper explores the use of different non-contact measurement devices on an industrial robot. The aim is to experimentally investigate the effects of robot movements on the accuracy and precision of measurements. The focus has been on assessing the ability to accurately measure various geometric and surface parameters of holes despite the inherent inaccuracies of industrial robot. This involves the measurement of diameter, roundness and surface roughness. The study also includes scanning of holes for measuring internal features such as start and end point of a taper. Two different non-contact measurement devices based on different technologies are investigated. Furthermore, effects of eccentricity, vibrations and thermal variations are also assessed. The research contributes towards the use of robots for highly accurate and precise robotic metrology.

  1. Noncontact 3-D Speckle Contrast Diffuse Correlation Tomography of Tissue Blood Flow Distribution.

    Science.gov (United States)

    Huang, Chong; Irwin, Daniel; Zhao, Mingjun; Shang, Yu; Agochukwu, Nneamaka; Wong, Lesley; Yu, Guoqiang

    2017-10-01

    Recent advancements in near-infrared diffuse correlation techniques and instrumentation have opened the path for versatile deep tissue microvasculature blood flow imaging systems. Despite this progress there remains a need for a completely noncontact, noninvasive device with high translatability from small/testing (animal) to large/target (human) subjects with trivial application on both. Accordingly, we discuss our newly developed setup which meets this demand, termed noncontact speckle contrast diffuse correlation tomography (nc_scDCT). The nc_scDCT provides fast, continuous, portable, noninvasive, and inexpensive acquisition of 3-D tomographic deep (up to 10 mm) tissue blood flow distributions with straightforward design and customization. The features presented include a finite-element-method implementation for incorporating complex tissue boundaries, fully noncontact hardware for avoiding tissue compression and interactions, rapid data collection with a diffuse speckle contrast method, reflectance-based design promoting experimental translation, extensibility to related techniques, and robust adjustable source and detector patterns and density for high resolution measurement with flexible regions of interest enabling unique application-specific setups. Validation is shown in the detection and characterization of both high and low contrasts in flow relative to the background using tissue phantoms with a pump-connected tube (high) and phantom spheres (low). Furthermore, in vivo validation of extracting spatiotemporal 3-D blood flow distributions and hyperemic response during forearm cuff occlusion is demonstrated. Finally, the success of instrument feasibility in clinical use is examined through the intraoperative imaging of mastectomy skin flap.

  2. Non-contact radio frequency shielding and wave guiding by multi-folded transformation optics method.

    Science.gov (United States)

    Madni, Hamza Ahmad; Zheng, Bin; Yang, Yihao; Wang, Huaping; Zhang, Xianmin; Yin, Wenyan; Li, Erping; Chen, Hongsheng

    2016-11-14

    Compared with conventional radio frequency (RF) shielding methods in which the conductive coating material encloses the circuits design and the leakage problem occurs due to the gap in such conductive material, non-contact RF shielding at a distance is very promising but still impossible to achieve so far. In this paper, a multi-folded transformation optics method is proposed to design a non-contact device for RF shielding. This "open-shielded" device can shield any object at a distance from the electromagnetic waves at the operating frequency, while the object is still physically open to the outer space. Based on this, an open-carpet cloak is proposed and the functionality of the open-carpet cloak is demonstrated. Furthermore, we investigate a scheme of non-contact wave guiding to remotely control the propagation of surface waves over any obstacles. The flexibilities of such multi-folded transformation optics method demonstrate the powerfulness of the method in the design of novel remote devices with impressive new functionalities.

  3. Non-contact evaluation of milk-based products using air-coupled ultrasound

    Science.gov (United States)

    Meyer, S.; Hindle, S. A.; Sandoz, J.-P.; Gan, T. H.; Hutchins, D. A.

    2006-07-01

    An air-coupled ultrasonic technique has been developed and used to detect physicochemical changes of liquid beverages within a glass container. This made use of two wide-bandwidth capacitive transducers, combined with pulse-compression techniques. The use of a glass container to house samples enabled visual inspection, helping to verify the results of some of the ultrasonic measurements. The non-contact pulse-compression system was used to evaluate agglomeration processes in milk-based products. It is shown that the amplitude of the signal varied with time after the samples had been treated with lactic acid, thus promoting sample destabilization. Non-contact imaging was also performed to follow destabilization of samples by scanning in various directions across the container. The obtained ultrasonic images were also compared to those from a digital camera. Coagulation with glucono-delta-lactone of skim milk poured into this container could be monitored within a precision of a pH of 0.15. This rapid, non-contact and non-destructive technique has shown itself to be a feasible method for investigating the quality of milk-based beverages, and possibly other food products.

  4. Assessment of human respiration patterns via noncontact sensing using Doppler multi-radar system.

    Science.gov (United States)

    Gu, Changzhan; Li, Changzhi

    2015-03-16

    Human respiratory patterns at chest and abdomen are associated with both physical and emotional states. Accurate measurement of the respiratory patterns provides an approach to assess and analyze the physical and emotional states of the subject persons. Not many research efforts have been made to wirelessly assess different respiration patterns, largely due to the inaccuracy of the conventional continuous-wave radar sensor to track the original signal pattern of slow respiratory movements. This paper presents the accurate assessment of different respiratory patterns based on noncontact Doppler radar sensing. This paper evaluates the feasibility of accurately monitoring different human respiration patterns via noncontact radar sensing. A 2.4 GHz DC coupled multi-radar system was used for accurate measurement of the complete respiration patterns without any signal distortion. Experiments were carried out in the lab environment to measure the different respiration patterns when the subject person performed natural breathing, chest breathing and diaphragmatic breathing. The experimental results showed that accurate assessment of different respiration patterns is feasible using the proposed noncontact radar sensing technique.

  5. Airborne non-contact and contact broadband ultrasounds for frequency attenuation profile estimation of cementitious materials.

    Science.gov (United States)

    Gosálbez, J; Wright, W M D; Jiang, W; Carrión, A; Genovés, V; Bosch, I

    2018-08-01

    In this paper, the study of frequency-dependent ultrasonic attenuation in strongly heterogeneous cementitious materials is addressed. To accurately determine the attenuation over a wide frequency range, it is necessary to have suitable excitation techniques. We have analysed two kinds of ultrasound techniques: contact ultrasound and airborne non-contact ultrasound. The mathematical formulation for frequency-dependent attenuation has been established and it has been revealed that each technique may achieve similar results but requires specific different calibration processes. In particular, the airborne non-contact technique suffers high attenuation due to energy losses at the air-material interfaces. Thus, its bandwidth is limited to low frequencies but it does not require physical contact between transducer and specimen. In contrast, the classical contact technique can manage higher frequencies but the measurement depends on the pressure between the transducer and the specimen. Cement specimens have been tested with both techniques and frequency attenuation dependence has been estimated. Similar results were achieved at overlapping bandwidth and it has been demonstrated that the airborne non-contact ultrasound technique could be a viable alternative to the classical contact technique. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. Activity coefficients in (hydrogen chloride+holmium chloride) (aq) from T=(278.15 to 328.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Roy, Rabindra N. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States)]. E-mail: rroy@drury.edu; Roy, Lakshmi N. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Tabor, Bennett J. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Richards, Sarah J. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Cummins, Mason P. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Himes, Curtis A. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Gibbs, Stephanie N. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States); Christiansen, Edward B. [Hoffman Department of Chemistry, Drury University, Springfield, MO 65802 (United States)

    2005-07-15

    Activity coefficients of HCl in (hydrogen chloride+holmium chloride) (aq) have been calculated from the observed e.m.f.s using the Nernst equation. The temperatures ranged from (278.15 to 328.15) K at 5 K intervals and at constant total ionic strengths of (0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, and 1.5) mol.kg{sup -1}. Electromotive-force measurements were made on the cell without liquid junction of the type:Pt vertical bar H{sub 2}(g,p=101.325kPa) vertical bar HCl(m{sub A}),HoCl{sub 3}(m{sub B}) vertical bar AgCl(s), vertical bar Ag(s) The results of the activity coefficients of HCl for this mixed electrolyte mixture have been interpreted in terms of the simpler Harned's equations and the ion-interaction model of Pitzer. Results show that the quadratic term is sufficient for the full range of Y{sub B} (the ionic strength fraction of the salt) to 0.9 at all the ionic strengths studied. The Pitzer's mixing parameters S{sub {theta}}{sub H,Ho} and {psi}{sub H,Ho,Cl} (including higher order electrostatic effects) and {theta}{sub H,Ho} and {psi}{sub H,Ho,Cl} (excluding higher order electrostatic effects) have been determined. These values at T=298.15 K are: S{sub {theta}}{sub H},{sub Ho}=0.115, {psi}{sub H,Ho,Cl}=-.071; and {theta}{sub H,Ho}=-.663, {psi}{sub H,Ho,Cl}=0.165. The parameters obtained in this study reproduce the activity coefficients of HCl in the mixtures within 0.015 over the entire range of ionic strengths and within 0.009 for I>=0.05 mol.kg{sup -1} over the entire temperature range.

  7. Production of dispersed nanometer sized YAG powders from alkoxide, nitrate and chloride precursors and spark plasma sintering to transparency

    International Nuclear Information System (INIS)

    Suarez, M.; Fernandez, A.; Menendez, J.L.; Torrecillas, R.

    2010-01-01

    Yttrium aluminum garnet (YAG) was synthesized from different starting materials, i.e., alkoxide, nitrate and chloride precursors. The conversion steps from the precursors to crystalline YAG were studied by Raman spectroscopy. Dispersed YAG powders were formed at a relatively low temperature, around 800 o C by the chlorides route, whereas alkoxide precursors needed firing over 900 o C and nitrates even over 1100 o C. Lyophilized YAG gel was sintered to transparency by the spark plasma sintering method at 1500 o C with in-line transmittances close to 60% at 680 nm and over 80% in the infrared range.

  8. In vitro studies of morphological changes in enamel surface after Er:YAG and Nd:YAG laser irradiation, by SEM

    International Nuclear Information System (INIS)

    Verlangieri, Eleonora Jaeger

    2001-01-01

    The caries prevention by using laser irradiation has been investigated by many authors using various lasers with different irradiations conditions. The purpose of this study was to investigated the morphological changes in enamel surface after Er:YAG and Nd:YAG laser irradiation, in vitro, by SEM. Fifteen freshly extracted, intact, caries-free, human third molars, were used in this study. The coronary portions were sectioned, from buccal to lingual direction, in two half-parts. Each one was irradiated by a different laser. The first one was irradiated with water-air spray, by a Nd:YAG laser, at 1.084 nm wave length, at 10 W, 10 Hz, 100 mJ for 60 sec., with an optical fiber in contact mode (0,32 mm of diameter); and the other half, with water-air spray by an Er:YAG laser at 2,94 micrometers wave length at the parameters of 4 Hz, 80 mJ, 24.95 J/cm 2 for 60 sec. The results of this study suggested that both lasers promoted morphological changes in the enamel surface enhancing resistance and can be an alternative clinical method for caries preventions. (author)

  9. [Is prophylactic YAG iridotomy useful in pigment dispersion syndrome?].

    Science.gov (United States)

    Rosentreter, A; Schwenn, O; Funk, J; Dietlein, T

    2013-04-01

    Despite theoretical considerations concerning the advantage of iridotomy in eyes with pigment dispersion syndrome or early pigment glaucoma, there is a lack of clinical evidence that this procedure has a long-term effect in preventing glaucoma damage under these circumstances. However, several factors may contribute to this lack of evidence, e.g. the statistical problem of a low conversion rate from pigment dispersion syndrome to pigment glaucoma or the inclusion criteria in the studies treating patients older than 40 years or genetic dispositions in pigment glaucoma that are not yet fully clear. On the basis of current data the decision for YAG iridotomy should only be taken in patients younger than 40 years, if the midperipheral iris shows an inverse bowing and the intraocular pressure is normal or slightly increased with no progressive signs of optic nerve damage. In cases of insufficient intraocular pressure and visual defects due to glaucomatous optic nerve damage, incisional glaucoma surgery is usually necessary especially in younger patients with a long life expectancy.

  10. Integrated chemical process for exothermic wave synthesis of high luminance YAG:Ce phosphors

    International Nuclear Information System (INIS)

    Won, C.W.; Nersisyan, H.H.; Won, H.I.; Youn, J.W.

    2011-01-01

    In this paper, high-luminance yellow-emitting Y 3 Al 5 O 12 :Ce 3+ phosphor (YAG:Ce) microparticles were prepared in a solid flame using a 1.425Y 2 O 3 +2.5Al 2 O 3 +0.15CeO 2 +k(KClO 3 +urea)+mNH 4 F precursor mixture (here k is the number of moles of the KClO 3 +urea red-ox mixture, and m is the number of moles of NH 4 F). The self-sustaining combustion process for the entire reaction sample was provided by the heat generated from the KClO 3 +urea mixture. Parametric studies demonstrated that the maximum temperature in the combustion wave varied from 885 to 1200 deg. C for k=2.0-3.0 mole and m=0-1.5 mole. X-ray analysis results showed that the product obtained in the solid flame consisted of Y 3 Al 5 O 12 :Ce 3+ and KCl phases. Therefore, after dissolving potassium chloride in distillated water, pure-phase YAG:Ce phosphor powder was obtained. The as-prepared YAG:Ce phosphor particles had diameters of 10-25 μm and good dispersity and exhibited luminescence properties comparable to those of YAG:Ce phosphor powders prepared by conventional high-temperature processing. - Highlights: → A new solid-flame strategy was developed for synthesizing high-luminance YAG:Ce phosphor. → Adding KClO 3 +CO(NH 2 ) 2 +NH 4 F mixture to oxide powders provides a low-temperature combustion process. → YAG:Ce phosphor particles 10-25 μm in diameter were obtained at 1000-1100 deg. C within tens of seconds. → As-prepared YAG:Ce emission intensity was 90.1-103.2% compared to that of the reference sample.

  11. Comparison of diode laser and Er:YAG lasers in the treatment of ankyloglossia.

    Science.gov (United States)

    Aras, Mutan Hamdi; Göregen, Mustafa; Güngörmüş, Metin; Akgül, Hayati Murat

    2010-04-01

    The purpose of this study was to compare the tolerance of lingual frenectomy with regard to a local anesthesia requirement and comparison of postsurgical discomfort experienced by patients operated on with both diode and erbium:yttrium-aluminium-garnet (Er:YAG) lasers. Ankyloglossia, commonly known as tongue-tie, is a congenital oral anomaly characterized by a short lingual frenulum. A short lingual frenulum may contribute to feeding, speech, and mechanical tongue problems. Sixteen referred patients with tongue mobility complaints were included in this study. A GaAlAs laser device with a continuous wavelength of 808 nm was used in the diode group. Frenulums were incised by applying 2 W of laser power. The Er:YAG laser device with a continuous wavelength of 2940 nm was used in the Er:YAG group. Frenulums were incised by applying 1 W of laser power. The acceptability of the lingual frenectomy without local anesthesia and the degree of the postsurgical discomfort were evaluated. Although the majority of patients (six) could be operated on without local anesthesia in the Er:YAG group, all patients could not be operated on without local anesthetic agent in the diode group. There were no differences between the two groups with regard to pain, chewing, and speaking on the first or seventh day after surgery, whereas patients had more pain in the Er:YAG group than in the diode group the first 3 h after surgery. The results indicate that only the Er:YAG laser can be used for lingual frenectomy without local anesthesia, and there was no difference between the two groups regarding the degree of the postsurgical discomfort except in the first 3 h. In conclusion, these results indicate that the Er:YAG laser is more advantageous than the diode laser in minor soft-tissue surgery because it can be performed without local anesthesia and with only topical anesthesia.

  12. Evaluation of the permeability and morphological alteration of the dental surface after apicoectomy, treatment and preparation with Er:YAG and Nd:YAG lasers

    International Nuclear Information System (INIS)

    Oliveira, Rodrigo Guerra de

    2001-01-01

    One of the objectives of endodontic treatment is to resolve pathological periapical processes caused by microbial contamination of the dental pulp. Correct execution of the necessary chemical preparation prior to surgery generally results in positive outcomes. However, a percentage of cases do not respond favorably and therefore require retreatment, a conservative therapeutic option. There are meanwhile a number of treatment failures which do not respond to these conservative measures and must therefore be subjected to paraendodontic surgical procedures. One of the principal problems of this therapeutic conduct is linked to the surface permeability of the dentin after apicoectomy and the lack of adequate marginal adaptation between the retrofilling material and the cavity walls. This permits the percolation of microorganisms and their metabolic by products from the system of root canals to the periapical region, thereby compromising the necessary tissue repair. The present work proposes the evaluation of the surface and marginal permeability of cut dentin after apicoectomy and treatment with Er:YAG and Nd:YAG lasers with fiber optics and then retrofilled with intermediate restorative material (IRM). A total of 24 single rooted teeth whose canals were endodontically treated were divided into 3 experimental groups: group I, whose apices were sectioned with an Er:YAG laser and the resulting cavity and the cut dental surface were irradiated with this laser via a 50/10 type fiber; in group II the apicoectomy was conducted with an Er:YAG laser and the resulting cavity and the cut surface were irradiated with a Nd:YAG laser; in group III, the samples were apicoectomized and the cavities were treated with a high speed bur (control group). Analysis of the infiltration of the dye methylene blue throughout the cut dental surface and the reconstruction demonstrated that the samples in the irradiated groups presented lower indices of infiltration than the control group. The

  13. Long-Term Outcomes of Laser Prostatectomy for Storage Symptoms: Comparison of Serial 5-Year Followup Data between High Performance System Photoselective Vaporization and Holmium Laser Enucleation of the Prostate.

    Science.gov (United States)

    Cho, Min Chul; Song, Won Hoon; Park, Juhyun; Cho, Sung Yong; Jeong, Hyeon; Oh, Seung-June; Paick, Jae-Seung; Son, Hwancheol

    2018-01-09

    We compared long-term storage symptom outcomes between photoselective laser vaporization of the prostate with a 120 W high performance system and holmium laser enucleation of the prostate. We also determined factors influencing postoperative improvement of storage symptoms in the long term. Included in our study were 266 men, including 165 treated with prostate photoselective laser vaporization using a 120 W high performance system and 101 treated with holmium laser enucleation of the prostate, on whom 60-month followup data were available. Outcomes were assessed serially 6, 12, 24, 36, 48 and 60 months postoperatively using the International Prostate Symptom Score, uroflowmetry and the serum prostate specific antigen level. Postoperative improvement in storage symptoms was defined as a 50% or greater reduction in the subtotal storage symptom score at each followup visit after surgery compared to baseline. Improvements in frequency, urgency, nocturia, subtotal storage symptom scores and the quality of life index were maintained up to 60 months after photoselective laser vaporization or holmium laser enucleation of the prostate. There was no difference in the degree of improvement in storage symptoms or the percent of patients with postoperative improvement in storage symptoms between the 2 groups throughout the long-term followup. However, the holmium laser group showed greater improvement in voiding symptoms and quality of life than the laser vaporization group. On logistic regression analysis a higher baseline subtotal storage symptom score and a higher BOOI (Bladder Outlet Obstruction Index) were the factors influencing the improvement in storage symptoms 5 years after prostate photoselective laser vaporization or holmium laser enucleation. Our serial followup data suggest that storage symptom improvement was maintained throughout the long-term postoperative period for prostate photoselective laser vaporization with a 120 W high performance system and holmium

  14. Robotic Assisted Simple Prostatectomy versus Holmium Laser Enucleation of the Prostate for Lower Urinary Tract Symptoms in Patients with Large Volume Prostate: A Comparative Analysis from a High Volume Center.

    Science.gov (United States)

    Umari, Paolo; Fossati, Nicola; Gandaglia, Giorgio; Pokorny, Morgan; De Groote, Ruben; Geurts, Nicolas; Goossens, Marijn; Schatterman, Peter; De Naeyer, Geert; Mottrie, Alexandre

    2017-04-01

    We report a comparative analysis of robotic assisted simple prostatectomy vs holmium laser enucleation of the prostate in patients who had benign prostatic hyperplasia with a large volume prostate (greater than 100 ml). A total of 81 patients underwent robotic assisted simple prostatectomy and 45 underwent holmium laser enucleation of the prostate in a 7-year period. Patients were preoperatively assessed with transrectal ultrasound and uroflowmetry. Functional parameters were assessed postoperatively during followup. Perioperative outcomes included operative time, postoperative hemoglobin, catheterization time and hospitalization. Complications were reported according to the Clavien-Dindo classification. Compared to the holmium laser enucleation group, patients treated with prostatectomy were significantly younger (median age 69 vs 74 years, p = 0.032) and less healthy (Charlson comorbidity index 2 or greater in 62% vs 29%, p = 0.0003), and had a lower rate of suprapubic catheterization (23% vs 42%, p = 0.028) and a higher preoperative I-PSS (International Prostate Symptom Score) (25 vs 21, p = 0.049). Both groups showed an improvement in the maximum flow rate (15 vs 11 ml per second, p = 0.7), and a significant reduction in post-void residual urine (-73 vs -100 ml, p = 0.4) and I-PSS (-20 vs -18, p = 0.8). Median operative time (105 vs 105 minutes, p = 0.9) and postoperative hemoglobin (13.2 vs 13.8 gm/dl, p = 0.08) were similar for robotic assisted prostatectomy and holmium laser enucleation, respectively. Median catheterization time (3 vs 2 days, p = 0.005) and median hospitalization (4 vs 2 days, p = 0.0001) were slightly shorter in the holmium laser group. Complication rates were similar with no Clavien grade greater than 3 in either group. Our results from a single center suggest comparable outcomes for robotic assisted simple prostatectomy and holmium laser enucleation of the prostate in patients with a large volume prostate. These findings require

  15. Er:YAG Laser and Fractured Incisor Restorations: An In Vitro Study

    Directory of Open Access Journals (Sweden)

    C. Fornaini

    2012-01-01

    Full Text Available Introduction. The aim of this study was to analyse the effects of an Er:YAG laser on enamel and dentine in cases of dental restorations involving fractured teeth, utilizing the dental fragment. Materials and Methods. Seventy-two freshly extracted bovine incisors were fractured at the coronal level by using a hammer applied with a standardized method, and the fragment was reattached by using three different methods: Er:YAG laser, orthophosphoric acid, and laser plus acid. The different groups were evaluated by a test realized with the dynamometer to know the force required to successfully detach the reattached fragment and by a microinfiltration test by using a 0.5% methylene blue solution followed by the optic microscope observation. Results. The compression test showed only a slight difference between the three groups, without any statistical significance. The infiltration test used to evaluate the marginal seal between the fracture fragment and the tooth demonstrated that etching with Er:YAG laser alone or in combination with orthophosphoric acid gives better results than orthophosphoric acid alone, with a highly significant statistical result. Discussion. Reattaching a tooth fragment represents a clinically proven methodology, in terms of achieving resistance to detachment, and the aim of this work was to demonstrate the advantages of Er:YAG laser on this procedure. Conclusion. This “in vitro” study confirms that Er:YAG laser can be employed in dental traumatology to restore frontal teeth after coronal fracture.

  16. Er:YAG delamination of immersed biological membranes using sealed flexible hollow waveguides

    Science.gov (United States)

    Sagi-Dolev, A. M.; Dror, Jacob; Inberg, Alexandra; Ferencz, J. R.; Croitoru, Nathan I.

    1996-04-01

    The radiation of Er-YAG laser ((lambda) equals 2.94 micrometer) gives selective interaction with tissues. The extinction in soft tissues is only a few micrometers and in hard tissues is of the order of hundreds of micrometers. This makes this type of laser very suitable for treatments in dentistry, orthopedy, or ophthalmology. Because the usual silica fibers are not transmitting the radiation at lambda equals 2.94 micrometer of this laser, many applications cannot be presently performed. Fused silica hollow fibers for Er-YAG radiation were developed in our laboratory and several possible applications in dentistry, orthopedy and ophthalmology were indicated. Hole opening and implantation preparation of teeth were experimented, using Er-YAG laser and hollow plastic waveguide delivery systems. Hole drilling in cow bones was demonstrated for applications in orthopedy. A new procedure of delivering Er-YAG radiation on fibrotic membranes of inner eggshell as a model of the membranes in eyes was developed employing silica hollow waveguides of 0.5 and 0.7 mm ID or a plastic waveguide of 1.0 mm ID. For this purpose waveguides with sealed distal tip were employed to enable us to approach the delivery system through liquid media near to the membrane. This experiment demonstrates the possibility of surgical applications in vitectomy in ophthalmology using Er-YAG laser and silica hollow waveguides.

  17. Management of intermittent angle closure glaucoma with Nd: yag laser iridotomy as a primary procedure

    International Nuclear Information System (INIS)

    Ahmed, M.

    2006-01-01

    To assess the efficacy and complications of Nd: YAG laser iridotomy in patients with intermittent (sub-acute) angle closure glaucoma. Twenty-five eyes of twenty-three patients with periodic (intermittent) angle closure, selected in outpatient department, were kept on pilocarpine until YAG laser iridotomy was performed. After YAG laser iridotomy oral acetazolamide and topical dexamethasone was used to control post laser rise of IOP and inflammation respectively. Patency of iridotomy was confirmed and intra-ocular pressure was measured one hour after the procedure. Immediate complication, if any, was noted. Follow-up was done for six months. Prophylactic laser iridotomy was done in fellow eye with occludable angle. Levene's test for equality of variance and t-test for equality of means were used for statistical analysis. This study revealed a significant difference in IOP before and after YAG laser iridotomy (p = .002). Complete follow-up of 6 months was possible in 25 eyes of 23 subjects. After YAG Laser iridotomy, 21 (84%) eyes showed negative provocative test, intraocular pressure below 19mm Hg without medication and anterior chamber angle no more occludable and were labeled successful. Iridotomy remained patent in 96% of eyes. Iridotomy failed to reduce IOP in 4 (16%) eyes. The complications were minimal and transient. (author)

  18. A primary exploration to quasi-two-dimensional rare-earth ferromagnetic particles: holmium-doped MoS2 sheet as room-temperature magnetic semiconductor

    Science.gov (United States)

    Chen, Xi; Lin, Zheng-Zhe

    2018-05-01

    Recently, two-dimensional materials and nanoparticles with robust ferromagnetism are even of great interest to explore basic physics in nanoscale spintronics. More importantly, room-temperature magnetic semiconducting materials with high Curie temperature is essential for developing next-generation spintronic and quantum computing devices. Here, we develop a theoretical model on the basis of density functional theory calculations and the Ruderman-Kittel-Kasuya-Yoshida theory to predict the thermal stability of two-dimensional magnetic materials. Compared with other rare-earth (dysprosium (Dy) and erbium (Er)) and 3 d (copper (Cu)) impurities, holmium-doped (Ho-doped) single-layer 1H-MoS2 is proposed as promising semiconductor with robust magnetism. The calculations at the level of hybrid HSE06 functional predict a Curie temperature much higher than room temperature. Ho-doped MoS2 sheet possesses fully spin-polarized valence and conduction bands, which is a prerequisite for flexible spintronic applications.

  19. Development of phosphate glass microspheres containing holmium for selective internal radiotherapy; Desenvolvimento de microesferas de vidro fosfato contendo holmio para uso em radioterapia interna seletiva

    Energy Technology Data Exchange (ETDEWEB)

    Barros Filho, Eraldo Cordeiro

    2016-11-01

    The selective internal radiotherapy is an alternative for some kinds of cancer as the hepatocellular carcinoma (HCC) or primary liver cancer treatment. In this treatment, glass or polymer microspheres containing radionuclides inside their structure are introduced in the liver through hepatic artery and trapped at the arterioles that feed the tumor. In this work, the development of phosphate glasses containing holmium for production of microspheres and their application in Brazil are proposed. The developed glasses presented suitable chemical durability, density of 2,7(3) g/cm{sup 3}, high thermal stability and the impurities contained therein do not preclude the treatment. The microspheres were produced by the flame method and the gravitational fall method, and were characterized by means of several techniques to evaluate shape, average particle size, activity and biocompatibility suitable for selective internal radiotherapy. Based in the main results, the submission to in vivo tests is proposed. (author)

  20. Flexible ureterorenoscopy (F-URS) with holmium laser versus extracorporeal shock wave lithotripsy (ESWL) for treatment of renal stone <2 cm: a meta-analysis.

    Science.gov (United States)

    Mi, Yuanyuan; Ren, Kewei; Pan, Haiyan; Zhu, Lijie; Wu, Sheng; You, Xiaoming; Shao, Hongbao; Dai, Feng; Peng, Tao; Qin, Feng; Wang, Jian; Huang, Yi

    2016-08-01

    The objective of the study was to systematically review the efficacy and safety of flexible ureterorenoscopy (F-URS) with holmium laser versus extracorporeal shock wave lithotripsy (ESWL) for the treatment of renal stone ESWL (WMD = 2.13, 95 % CI 1.13-4.00, P = 0.02). F-URS is associated with higher SFR, lower APR and RR than ESWL. F-URS is a safe and effective procedure. It can successfully treat patients with stones for 1-2 cm, especially for lower pole stone, without increasing complications, operative time and hospital stay. F-URS can be used as an alternative treatment to ESWL in selected cases with larger renal stones. However, further randomized trials are needed to confirm these findings.

  1. Plasma plume expansion dynamics in nanosecond Nd:YAG laserosteotome

    Science.gov (United States)

    Abbasi, Hamed; Rauter, Georg; Guzman, Raphael; Cattin, Philippe C.; Zam, Azhar

    2018-02-01

    In minimal invasive laser osteotomy precise information about the ablation process can be obtained with LIBS in order to avoid carbonization, or cutting of wrong types of tissue. Therefore, the collecting fiber for LIBS needs to be optimally placed in narrow cavities in the endoscope. To determine this optimal placement, the plasma plume expansion dynamics in ablation of bone tissue by the second harmonic of a nanosecond Nd:YAG laser at 532 nm has been studied. The laserinduced plasma plume was monitored in different time delays, from one nanosecond up to one hundred microseconds. Measurements were performed using high-speed gated illumination imaging. The expansion features were studied using illumination of the overall visible emission by using a gated intensified charged coupled device (ICCD). The camera was capable of having a minimum gate width (Optical FWHM) of 3 ns and the timing resolution (minimum temporal shift of the gate) of 10 ps. The imaging data were used to generate position-time data of the luminous plasma-front. Moreover, the velocity of the plasma plume expansion was studied based on the time-resolved intensity data. By knowing the plasma plume profile over time, the optimum position (axial distance from the laser spot) of the collecting fiber and optimal time delay (to have the best signal to noise ratio) in spatial-resolved and time-resolved laser-induced breakdown spectroscopy (LIBS) can be determined. Additionally, the function of plasma plume expansion could be used to study the shock wave of the plasma plume.

  2. Site preference and elastic properties of ternary alloying additions in B2 YAg alloys by first-principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yurong, E-mail: winwyr@126.com [College of Electromechanical Engineering, Hunan University of Science and Technology, Xiantang 411201 (China); Hu Wangyu [Department of Applied Physics, Hunan University, Changsha 410082 (China); Xu Longshan [Department of Materials Science and Engineering, Xiamen University of Technology, Xiamen 361024 (China)

    2012-09-15

    First-principles calculations were preformed to study the site preference behavior and elastic properties of 3d (Ti-Cu) transition-metal elements in B2 ductility YAg alloy. In YAg, Ti is found to occupy the Y sublattice whereas V, Cr, Co, Fe, Ni and Cu tend to substitute for Ag sublattice. Due to the addition of 3d transition metals, the lattice parameters of YAg is decreased in the order: VYAg alloy, and Fe is the most effective element to improve the ductility of YAg, while Ti, Ni and V alloying elements can reduce the ductility of YAg alloy, especially, V transforms ductile into brittle for YAg alloy. In addition, both V and Ni alloying elements can increase the hardness of YAg alloy, and Y{sub 8}Ag{sub 7}V is harder than Y{sub 8}Ag{sub 7}Ni.

  3. Laser amplification of optical images using a CW Nd:YAG amplifier

    International Nuclear Information System (INIS)

    Aman, H

    2013-01-01

    In this paper a scheme for the amplification of optical images is described, using a continuous wave (CW) diode-pumped Nd:YAG (yttrium aluminum garnet) laser module. A passively q-switched end-pumped Nd:YAG laser is used as a pump source, which carries the optical image distribution as an input which is transmitted towards the amplifier at a distance of about ten feet. For amplification, a three-side-pumped CW Nd:YAG laser module is utilized without the cavity mirrors. In this way, optical images are amplified by a factor of 3.2 and imaged at a distance of ten feet with a spatial resolution of 500 μm. (paper)

  4. Laser-diode pumped 40-W Yb:YAG ceramic laser.

    Science.gov (United States)

    Hao, Qiang; Li, Wenxue; Pan, Haifeng; Zhang, Xiaoyi; Jiang, Benxue; Pan, Yubai; Zeng, Heping

    2009-09-28

    We demonstrated a high-power continuous-wave (CW) polycrystalline Yb:YAG ceramic laser pumped by fiber-pigtailed laser diode at 968 nm with 400 mum fiber core. The Yb:YAG ceramic laser performance was compared for different Yb(3+) ion concentrations in the ceramics by using a conventional end-pump laser cavity consisting of two flat mirrors with output couplers of different transmissions. A CW laser output of 40 W average power with M(2) factor of 5.8 was obtained with 5 mol% Yb concentration under 120 W incident pump power. This is to the best of our knowledge the highest output power in end-pumped bulk Yb:YAG ceramic laser.

  5. Neodymium-YAG laser core through urethrotomy in obliterative posttraumatic urethral strictures after failed initial urethroplasty.

    Science.gov (United States)

    Dogra, P N; Nabi, G

    2002-01-01

    To assess the feasibility, problems and results of Nd-YAG laser core through urethrotomy in the management of failed urethroplasty for posttraumatic bulbomembranous urethral strictures. 61 patients with obliterative posttraumatic urethral strictures were treated by Nd-YAG laser core through urethrotomy between May 1997 to April 2000. Of these, 5 patients had failed end-to-end urethroplasty done as an initial procedure at various periods of time. The procedure was performed as day care and patients were discharged within 6 h of procedure. At 24-30 months of follow-up, all patients are voiding well and are continent. Auxiliary procedures were required in 2 cases. Nd-YAG laser core through urethrotomy is a feasible day care option for patients of obliterative urethral strictures following failed initial urethroplasty with successful outcome. Copyright 2002 S. Karger AG, Basel

  6. Neodymium:YAG laser cutting of intraocular lens haptics in vitro and in vivo.

    Science.gov (United States)

    Feder, J M; Rosenberg, M A; Farber, M D

    1989-09-01

    Various complications following intraocular lens (IOL) surgery result in explantation of the lenses. Haptic fibrosis may necessitate cutting the IOL haptics prior to removal. In this study we used the neodymium: YAG (Nd:YAG) laser to cut polypropylene and poly(methyl methacrylate) (PMMA) haptics in vitro and in rabbit eyes. In vitro we were able to cut 100% of both haptic types successfully (28 PMMA and 30 polypropylene haptics). In rabbit eyes we were able to cut 50% of the PMMA haptics and 43% of the polypropylene haptics. Poly(methyl methacrylate) haptics were easier to cut in vitro and in vivo than polypropylene haptics, requiring fewer shots for transection. Complications of Nd:YAG laser use frequently interfered with haptic transections in rabbit eyes. Haptic transection may be more easily accomplished in human eyes.

  7. Localization of the pumping reflector for a Nd:YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwang Suk; Kim, Chul Joong [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-12-01

    For the first year plan of this program, the pumping reflectors, which are gold plated reflectors and ceramic diffuse reflectors, of the Nd:YAG laser have been localized. The laser output performances with these reflectors have been investigated. Developed reflectors can be applied successfully to our commercialized Nd:YAG laser which was worked in previous project. We designed the optical pumping system with GaAlAs diode laser bar to improve the pumping efficiency. Moreover, we investigated a simple pumping technique without changing the fleshlamp, which makes the Nd:YAG laser operate in a cw, a pulsed, and a mixed of the two mode. We expert many new applications of this diversification of output pulse shapes in industry and in medicine. 38 figs, 9 tabs, 18 refs. (Author).

  8. Study on growth techniques and macro defects of large-size Nd:YAG laser crystal

    Science.gov (United States)

    Quan, Jiliang; Yang, Xin; Yang, Mingming; Ma, Decai; Huang, Jinqiang; Zhu, Yunzhong; Wang, Biao

    2018-02-01

    Large-size neodymium-doped yttrium aluminum garnet (Nd:YAG) single crystals were grown by the Czochralski method. The extinction ratio and wavefront distortion of the crystal were tested to determine the optical homogeneity. Moreover, under different growth conditions, the macro defects of inclusion, striations, and cracking in the as-grown Nd:YAG crystals were analyzed. Specifically, the inclusion defects were characterized using scanning electron microscopy and energy dispersive spectroscopy. The stresses of growth striations and cracking were studied via a parallel plane polariscope. These results demonstrate that improper growth parameters and temperature fields can enhance defects significantly. Thus, by adjusting the growth parameters and optimizing the thermal environment, high-optical-quality Nd:YAG crystals with a diameter of 80 mm and a total length of 400 mm have been obtained successfully.

  9. An ultrasonically levitated noncontact stage using traveling vibrations on precision ceramic guide rails.

    Science.gov (United States)

    Koyama, Daisuke; Ide, Takeshi; Friend, James R; Nakamura, Kentaro; Ueha, Sadayuki

    2007-03-01

    This paper presents a noncontact sliding table design and measurements of its performance via ultrasonic levitation. A slider placed atop two vibrating guide rails is levitated by an acoustic radiation force emitted from the rails. A flexural traveling wave propagating along the guide rails allows noncontact transportation of the slider. Permitting a transport mechanism that reduces abrasion and dust generation with an inexpensive and simple structure. The profile of the sliding table was designed using the finite-element analysis (FEA) for high levitation and transportation efficiency. The prototype sliding table was made of alumina ceramic (Al2O3) to increase machining accuracy and rigidity using a structure composed of a pair of guide rails with a triangular cross section and piezoelectric transducers. Two types of transducers were used: bolt-clamped Langevin transducers and bimorph transducers. A 40-mm long slider was designed to fit atop the two rail guides. Flexural standing waves and torsional standing waves were observed along the guide rails at resonance, and the levitation of the slider was obtained using the flexural mode even while the levitation distance was less than 10 microm. The levitation distance of the slider was measured while increasing the slider's weight. The levitation pressure, rigidity, and vertical displacement amplitude of the levitating slider thus were measured to be 6.7 kN/m2, 3.0 kN/microm/m2, and less than 1 microm, respectively. Noncontact transport of the slider was achieved using phased drive of the two transducers at either end of the vibrating guide rail. By controlling the phase difference, the slider transportation direction could be switched, and a maximum thrust of 13 mN was obtained.

  10. Noncontact tomography and a pH-sensitive nanocomposite for monitoring osseointegrated prosthesis interfaces

    Science.gov (United States)

    Gupta, Sumit; Loh, Kenneth J.

    2017-04-01

    The main objective of this research is to develop a noncontact and noninvasive method for monitoring infections at the interface of human tissue and osseointegrated prostheses. The technique used here is centered on the theory of a noncontact permittivity imaging technique known as electrical capacitance tomography (ECT). This work is divided into two main parts. First, an ECT electrical permittivity reconstruction software and hardware system was developed. Second, a carbon nanotube-polyaniline nanocomposite thin film was designed and fabricated such that its electrical permittivity is sensitive to pH stimuli. The dielectric properties of this thin film were characterized as it was exposed to different pH buffer solutions. It is envisioned that osseointegrated implants can be pre-coated with the pH-sensitive nanocomposite prior to implant. When infection occurs and alters the local pH of tissue at the human-prosthesis interface, the dielectric property of the film would change accordingly. Then, ECT can interrogate the cross-section of the human limb and reconstruct its permittivity distribution, revealing localized changes in permittivity due to infection. To validate this concept, a prosthesis phantom was coated with the nanocomposite pH sensor and then immersed in different pH buffer solutions. ECT was conducted, and the results showed that the magnitude and location of subsurface, localized, pH changes could be detected. In general, noncontact tomography coupled with stimuliresponsive thin films could pave way for new modalities of noninvasive human body imaging, in particular, for patients with osseointegrated implants and prostheses.

  11. Neonatal non-contact respiratory monitoring based on real-time infrared thermography

    Directory of Open Access Journals (Sweden)

    Abbas Abbas K

    2011-10-01

    Full Text Available Abstract Background Monitoring of vital parameters is an important topic in neonatal daily care. Progress in computational intelligence and medical sensors has facilitated the development of smart bedside monitors that can integrate multiple parameters into a single monitoring system. This paper describes non-contact monitoring of neonatal vital signals based on infrared thermography as a new biomedical engineering application. One signal of clinical interest is the spontaneous respiration rate of the neonate. It will be shown that the respiration rate of neonates can be monitored based on analysis of the anterior naris (nostrils temperature profile associated with the inspiration and expiration phases successively. Objective The aim of this study is to develop and investigate a new non-contact respiration monitoring modality for neonatal intensive care unit (NICU using infrared thermography imaging. This development includes subsequent image processing (region of interest (ROI detection and optimization. Moreover, it includes further optimization of this non-contact respiration monitoring to be considered as physiological measurement inside NICU wards. Results Continuous wavelet transformation based on Debauches wavelet function was applied to detect the breathing signal within an image stream. Respiration was successfully monitored based on a 0.3°C to 0.5°C temperature difference between the inspiration and expiration phases. Conclusions Although this method has been applied to adults before, this is the first time it was used in a newborn infant population inside the neonatal intensive care unit (NICU. The promising results suggest to include this technology into advanced NICU monitors.

  12. The high-sensitive magnetic levitated electrode ionization chamber of the noncontacting type

    International Nuclear Information System (INIS)

    Kawaguchi, Toshiro; Yoshimura, Atsushi

    1999-01-01

    There are two types of ionization chamber using magnetically levitated electrode: one is that by Tanaka et al. and the other, by authors'. The latter lacks the sensitivity relative to the former and thereby to solve the problem, authors made an improvement so that the electrode charge could be readout by noncontact after the leviated electrode was electrified by noncontact for an interval. This new type ionization chamber made it possible to measure the quite low dose radiation with stability and high sensitivity. Actually, the electrode was suspended by the teflon thread fixed on the steel cup levitated magnetically in the ionization chamber of which wall was covered by Al and equipped with an electrostatic charger for the electrode by noncontact. After measurement, the electrode was moved in the Faraday cage placed under the chamber to readout the voltage. For operation conditions of the apparatus, observation was done on the relationship between ionization current by 137 Cs and the applied voltage. For actual measurement, ionizations by low dose γ ray derived from KCl which containing 40 K in a small amount and by Rn at the fine and rainy days were measured. The exposure rate by KCl (500 g bottle) was found to be 12.7 x 10 -10 C/kg·h with the background value of 9.8 x 10 -10 . Rn concentrations in the air were 112.3 and 18.34 Bq/m 3 for 1 hr in the rainy and fine day, respectively, in Fukuoka City. (K.H.)

  13. A study on non-contact ultrasonic technique for on-line inspection of CFRP

    International Nuclear Information System (INIS)

    Lee, Seung-Joon; Park, Won-Su; Lee, Joon-Hyun; Byun, Joon-Hyung

    2007-01-01

    The advantages of carbon fiber reinforced plastic materials (CFRP) are: they are light structure materials, they have corrosion resistance, and higher specific strength and elasticity. The recently developed 3-dimentional fiber placement system is able to produce a more complex and various shaped structures due to less limitations of a product shape according to the problem in conventional fabrication process. This fiber placement system stacks the narrow prepreg tape on the mold according to the designed sequence and thickness. Non-destructive evaluation was rquired for these composites to evaluate changes in strength caused by defects such as delamination and porosity. Additionally, the expectent quality should be satisfied for the high cost fabrication process using the fiber placement system. Therefore, an on line non-destructive evaluation system is required and real-time complement is needed when the defects are detected [1]. Defect imaging by the ultrasonic C-scan method is a useful technique for defect detection in CFRP. However, the conventional ultrasonic C-scan technique cannot be applied during the fabrication process because the test piece should be immersed into the water. Therefore, non-contact ultrasonic techniques should be applied during the fabricating process. For the development of non-contact ultrasonic techniques available in non-destructive evaluation of CFRP, a recent laser-generated ultrasonic technique and an air-coupled transducer that transmit and receive ultrasounds in the air are studied [2-3]. In this study, generating and receiving techniques of laser-generated ultrasound and the characteristics of received signals upon the internal defects of CFRO were studied for non-contact inspection

  14. Dynamic balance performance and noncontact lower extremity injury in college football players: an initial study.

    Science.gov (United States)

    Butler, Robert J; Lehr, Michael E; Fink, Michael L; Kiesel, Kyle B; Plisky, Phillip J

    2013-09-01

    Field expedient screening tools that can identify individuals at an elevated risk for injury are needed to minimize time loss in American football players. Previous research has suggested that poor dynamic balance may be associated with an elevated risk for injury in athletes; however, this has yet to be examined in college football players. To determine if dynamic balance deficits are associated with an elevated risk of injury in collegiate football players. It was hypothesized that football players with lower performance and increased asymmetry in dynamic balance would be at an elevated risk for sustaining a noncontact lower extremity injury. Prospective cohort study. Fifty-nine collegiate American football players volunteered for this study. Demographic information, injury history, and dynamic balance testing performance were collected, and noncontact lower extremity injuries were recorded over the course of the season. Receiver operator characteristic curves were calculated based on performance on the Star Excursion Balance Test (SEBT), including composite score and asymmetry, to determine the population-specific risk cut-off point. Relative risk was then calculated based on these variables, as well as previous injury. A cut-off point of 89.6% composite score on the SEBT optimized the sensitivity (100%) and specificity (71.7%). A college football player who scored below 89.6% was 3.5 times more likely to get injured. Poor performance on the SEBT may be related to an increased risk for sustaining a noncontact lower extremity injury over the course of a competitive American football season. College football players should be screened preseason using the SEBT to identify those at an elevated risk for injury based upon dynamic balance performance to implement injury mitigation strategies to this specific subgroup of athletes.

  15. Diode pumped holmium, thulium and erbium lasers between 2 and 3μm operating CW at room temperature

    International Nuclear Information System (INIS)

    Esterowitz, L.

    1989-01-01

    Diode pumped CW lasers operating between 2 and 3 μm in the heavy rare earth activator ions are reviewed. In Ho, Tm:YAG the authors have demonstrated high efficiency using TM as the sensitizer ion which absorbed the pump radiation. This is followed by a cross relaxation process which allows nearly two excited Tm ions to be produced from one absorbed photon. There is rapid energy migration among the Tm ions followed by energy transfer to the Ho ion. The 2 μm laser action is to a level 460 cm -1 above the ground state. In Tm, Ho:YLF the authors have demonstrated CW cascade laser emission at 2.31 and 2.08 μm. Above threshold for both transitions, two infrared photons are produced for each absorbed pump photon. The theoretical slope efficiency of this system is 72.3% for pumping at 0.791 μm. In Er:YLF CW laser emission at 2.8 μm with a 10% slope efficiency is demonstrated

  16. Multiple minimally invasive Erbium:YAG laser mini-peels for skin rejuvenation: An objective assessment

    Science.gov (United States)

    El-Domyati, Moetaz; El-Ammawi, Tarek S.; Medhat, Walid; Moawad, Osama; Mahoney, Mỹ G.; Uitto, Jouni

    2012-01-01

    Summary Background As the demand for minimally invasive rejuvenation is increasing, micro-peel resurfacing using Erbium:Yttrium Aluminium Garnet (Er:YAG ) laser 2940 nm has been reported for the treatment of photoaged skin without ablation of the epidermis. However, little is known about the efficacy and underlying histologic changes associated with this type of treatment. Aims The purpose of this study is to evaluate the clinical effect and objectively quantify the histological changes in response to multiple sessions of Er:YAG laser 2940 nm mini-peels. Patients and methods Six female volunteers of Fitzpatrick skin type III-IV and Glogau’s class I-III wrinkles were subjected to six microresurfacing peels at 2-week intervals using Er:YAG 2940 nm laser at sub-ablative fluences of 2 - 3 J/cm2 to treat periorbital rhytides. Quantitative evaluation of collagen types I, III and VII, newly synthesized collagen, total elastin and tropoelastin was performed by histochemistry and immunohistochemistry coupled with computerized morphometric analysis at base line, end of treatment, and three months post treatment. Results Compared to the base line, evaluation of volunteers revealed obvious clinical improvement in response to Er:YAG mini-peels. Collagen types I, III, and VII, as well as newly synthesized collagen, together with tropoelastin showed a statistically significant increase in response to treatment, while the mean level of total elastin was significantly decreased in response to treatment. However, this was followed by regression of improvement at 3 months post treatment, but was still better than baseline. Conclusions The present study revealed that multiple Er:YAG mini-peels is a promising treatment option for photoaging as it reverses the signs of photoaged skin with little downtime and side effects. However, to maintain the short term improvement achieved after treatment, continued Er:YAG 2940 nm laser mini-peels is required. PMID:22672276

  17. Laser performance and modeling of RE3+:YAG double-clad crystalline fiber waveguides

    Science.gov (United States)

    Li, Da; Lee, Huai-Chuan; Meissner, Stephanie K.; Meissner, Helmuth E.

    2018-02-01

    We report on laser performance of ceramic Yb:YAG and single crystal Tm:YAG double-clad crystalline fiber waveguide (CFW) lasers towards the goal of demonstrating the design and manufacturing strategy of scaling to high output power. The laser component is a double-clad CFW, with RE3+:YAG (RE = Yb, Tm respectively) core, un-doped YAG inner cladding, and ceramic spinel or sapphire outer cladding. Laser performance of the CFW has been demonstrated with 53.6% slope efficiency and 27.5-W stable output power at 1030-nm for Yb:YAG CFW, and 31.6% slope efficiency and 46.7-W stable output power at 2019-nm for Tm:YAG CFW, respectively. Adhesive-Free Bond (AFB®) technology enables a designable refractive index difference between core and inner cladding, and designable core and inner cladding sizes, which are essential for single transverse mode CFW propagation. To guide further development of CFW designs, we present thermal modeling, power scaling and design of single transverse mode operation of double-clad CFWs and redefine the single-mode operation criterion for the double-clad structure design. The power scaling modeling of double-clad CFW shows that in order to achieve the maximum possible output power limited by the physical properties, including diode brightness, thermal lens effect, and simulated Brillion scattering, the length of waveguide is in the range of 0.5 2 meters. The length of an individual CFW is limited by single crystal growth and doping uniformity to about 100 to 200 mm lengths, and also by availability of starting crystals and manufacturing complexity. To overcome the limitation of CFW lengths, end-to-end proximity-coupling of CFWs is introduced.

  18. Effect of Nd:YAG laser on the solvent evaporation of adhesive systems.

    Science.gov (United States)

    Batista, Graziela Ribeiro; Barcellos, Daphne Câmara; Rocha Gomes Torres, Carlos; Damião, Álvaro José; de Oliveira, Hueder Paulo Moisés; de Paiva Gonçalves, Sérgio Eduardo

    2015-01-01

    This study evaluated the influence of Nd:YAG laser on the evaporation degree (ED) of the solvent components in total-etch and self-etch adhesives. The ED of Gluma Comfort Bond (Heraeus-Kulzer) one-step self-etch adhesive, and Adper Single Bond 2 (3M ESPE), and XP Bond (Dentsply) total-etch adhesives was determined by weight alterations using two techniques: Control--spontaneous evaporation of the solvent for 5 min; Experimental--Nd:YAG laser irradiation for 1 min, followed by spontaneous evaporation for 4 min. The weight loss due to evaporation of the volatile components was measured at baseline and after 10 s, 20 s, 30 s, 40 s, 50 s, 60 s, 70 s, 80 s, 90 s, 100 s, 110 s, 2 min, 3 min, 4 min, and 5 min. Evaporation of solvent components significantly increased with Nd:YAG laser irradiation for all adhesives investigated. Gluma Comfort Bond showed significantly higher evaporation of solvent components than Adper Single Bond 2 and XP Bond. All the adhesives lost weight quickly during the first min of Nd:YAG laser irradiation. The application of Nd:YAG laser on adhesives before light curing had a significant effect on the evaporation of the solvent components, and the ED of Gluma Comfort Bond one-step self-etch adhesive was significantly higher than with Adper Single Bond 2 and XP Bond total-etch adhesives. The use of the Nd:YAG laser on the uncured adhesive technique can promote a greater ED of solvents, optimizing the longevity of the adhesive restorations.

  19. A non-contact complete knee dislocation with popliteal artery disruption, a rare martial arts injury.

    Science.gov (United States)

    Viswanath, Y K; Rogers, I M

    1999-09-01

    Complete knee dislocation is a rare injury and an associated incidence of popliteal artery damage ranges from 16-60% of cases. It occurs commonly in road traffic accidents and in high velocity trauma where significant contact remains as the usual mode of injury. We describe a rare case of non-contact knee dislocation with popliteal artery injury sustained while practising Aikido, a type of martial art. This patient successfully underwent closed reduction of the knee with an emergency vein bypass graft. Similar injury in association with Aikido has not been described in the English literature previously. Various martial art injuries are briefly discussed and safety recommendations made.

  20. Temperature Identification in the Structural Elements of Non-Contacting Face Seals by Using Trefftz Functions

    Directory of Open Access Journals (Sweden)

    Anna PAWIŃSKA

    2014-12-01

    Full Text Available Phenomena of the heat transfer in non-contacting face seals was described by partial differential equation of the second order and boundary conditions. In this way, the mathematical model was developed for the sealing rings. The distributions of temperature in the structural elements was obtained by the Trefftz method. It is a simple method of solving direct and inverse problems described by a homogeneous or an inhomogeneous partial differential equation. The main idea of the method is to determine functions satisfying a given differential equation (Trefftz functions and to fit the linear combination of them to the governing boundary conditions.

  1. Procedure of non-contacting local mass density and mass density distribution measurements

    International Nuclear Information System (INIS)

    Menzel, M.; Winkler, K.

    1985-01-01

    The invention has been aimed at a procedure of non-contacting local mass density and/or mass density distribution measurements i.e. without the interfering influence of sensors or probes. It can be applied to installations, apparatuses and pipings of chemical engineering, to tank constructions and transportation on extreme temperature and/or pressure conditions and aggressive media influences respectively. The procedure has utilized an ionizing quantum radiation whereby its unknown weakening and scattering is compensated by a suitable combination of scattering and transmission counter rate measurements in such a way that the local mass densities and the mass density distribution respectively are determinable

  2. Phenomenally High Transduction Air/gas Transducers for Practical Non-Contact Ultrasonic Applications

    Science.gov (United States)

    Bhardwaj, Mahesh C.

    2009-03-01

    Based on novel acoustic impedance matching layers and high coupling piezoelectric materials this paper describes exceptionally high air/gas transduction ultrasonic transducers. By providing applications oriented performance of these transducers we also usher in the era of much desired Non-Contact Ultrasound (NCU) testing and analysis of a wide range of materials including early stage formation of materials such as uncured composite prepregs, green ceramics and powder metals, plastics, elastomers, porous, hygroscopic, chemically bonded and other materials. Besides quality control, ultimately NCU offers timely opportunities for cost-effective materials production, energy savings, and environment protection.

  3. Long wavelength infrared radiation thermometry for non-contact temperature measurements in gas turbines

    Science.gov (United States)

    Manara, J.; Zipf, M.; Stark, T.; Arduini, M.; Ebert, H.-P.; Tutschke, A.; Hallam, A.; Hanspal, J.; Langley, M.; Hodge, D.; Hartmann, J.

    2017-01-01

    The objective of the EU project "Sensors Towards Advanced Monitoring and Control of Gas Turbine Engines (acronym STARGATE)" is the development of a suite of advanced sensors, instrumentation and related systems in order to contribute to the developing of the next generation of green and efficient gas turbine engines. One work package of the project deals with the design and development of a long wavelength infrared (LWIR) radiation thermometer for the non-contact measurement of the surface temperature of thermal barrier coatings (TBCs) during the operation of gas turbine engines. For opaque surfaces (e.g. metals or superalloys) radiation thermometers which are sensitive in the near or short wavelength infrared are used as state-of-the-art method for non-contact temperature measurements. But this is not suitable for oxide ceramic based TBCs (e.g. partially yttria stabilized zirconia) as oxide ceramics are semi-transparent in the near and short wavelength infrared spectral region. Fortunately the applied ceramic materials are non-transparent in the long wavelength infrared and additionally exhibit a high emittance in this wavelength region. Therefore, a LWIR pyrometer can be used for non-contact temperature measurements of the surfaces of TBCs as such pyrometers overcome the described limitation of existing techniques. For performing non-contact temperature measurements in gas turbines one has to know the infrared-optical properties of the applied TBCs as well as of the hot combustion gas in order to properly analyse the measurement data. For reaching a low uncertainty on the one hand the emittance of the TBC should be high (>0.9) in order to reduce reflections from the hot surrounding and on the other hand the absorbance of the hot combustion gas should be low (<0.1) in order to decrease the influence of the gas on the measured signal. This paper presents the results of the work performed by the authors with focus on the implementation of the LWIR pyrometer and the

  4. Dynamic contour tonometry (DCT) versus non-contact tonometry (NCT): a comparison study.

    Science.gov (United States)

    Burvenich, H; Burvenich, E; Vincent, C

    2005-01-01

    In a prospective study we measured the intraocular pressure (IOP) by means of a Non-Contact Tonometer (NCT) and by means of a Pascal Dynamic Contour Tonometer (DCT), and the Central Corneal Thickness (CCT) by means of a contact pachymeter in 294 emmetropic or ametropic eyes. There is a linear relation between NCT and CCT. This linear relation doesn't exist between DCT and CCT. The same measurements were done before and 6 weeks after a Lasik intervention in 58 myopic eyes. Lasik intervention influences NCT but doesn't influence DCT.

  5. The Pulsair-Keeler non-contact tonometer in self-tonometry: preliminary results.

    Science.gov (United States)

    Boles Carenini, B; Brogliatti, B; Tonetto, C; Renis, E

    1992-09-01

    The authors considered the possibility of using the Pulsair-Keeler non-contact tonometer in self-tonometry. For this reason, 45 patients have been trained to use the instrument and, after a reasonable trial period, were able to self-measure their IOP. The results have been compared to the tonometric values measured with Goldmann tonometer to evaluate statistically the limits and the dependability of this method of measurement. The results shows that self-tonometry with the Pulsair-Keeler tonometer can be used in monitoring glaucomatous patients at home.

  6. A bendable and wearable cardiorespiratory monitoring device fusing two noncontact sensor principles.

    Science.gov (United States)

    Teichmann, Daniel; De Matteis, Dennis; Bartelt, Thorsten; Walter, Marian; Leonhardt, Steffen

    2015-05-01

    A mobile device is presented for monitoring both respiration and pulse. The device is developed as a bendable/flexible inlay that can be placed in a shirt pocket or the inside pocket of a jacket. To achieve optimum monitoring performance, the device combines two sensor principles, which work in a safe noncontact way through several layers of cotton or other textiles. One sensor, based on magnetic induction, is intended for respiratory monitoring, and the other is a reflective photoplethysmography sensor intended for pulse detection. Because each sensor signal has some dependence on both physiological parameters, fusing the sensor signals allows enhanced signal coverage.

  7. Noncontact rack-pinion-rack device as a differential vibration sensor.

    Science.gov (United States)

    Miri, MirFaez; Nasiri, Mojtaba

    2010-07-01

    We study a nanoscale system composed of one corrugated cylinder (pinion) placed between two corrugated plates (racks). The pinion and racks have no mechanical contact, but are coupled via the lateral Casimir force-one of the most spectacular consequences of quantum fluctuations of the electromagnetic field. The noncontact design of the device could help with the noteworthy wear problem in nanoscale mechanical systems. We consider the case where both racks undergo harmonic lateral motion. We assume that the amplitude, frequency, and phase of one of the racks are known. We show that probing the pinion motion, one can determine the vibration characteristics of the other rack.

  8. Noncontact thermometry via laser pumped, thermographic phosphors: Characterization of systematic errors and industrial applications

    International Nuclear Information System (INIS)

    Gillies, G.T.; Dowell, L.J.; Lutz, W.N.; Allison, S.W.; Cates, M.R.; Noel, B.W.; Franks, L.A.; Borella, H.M.

    1987-10-01

    There are a growing number of industrial measurement situations that call for a high precision, noncontact method of thermometry. Our collaboration has been successful in developing one such method based on the laser-induced fluorescence of rare-earth-doped ceramic phosphors like Y 2 O 3 :Eu. In this paper, we summarize the results of characterization studies aimed at identifying the sources of systematic error in a laboratory-grade version of the method. We then go on to present data from measurements made in the afterburner plume of a jet turbine and inside an operating permanent magnet motor. 12 refs., 6 figs

  9. Speckle-based off-axis holographic detection for non-contact photoacoustic tomography

    Directory of Open Access Journals (Sweden)

    Buj C.

    2015-09-01

    Full Text Available A very fast innovative holographic off-axis non-contact detection method for Photoacoustic Tomography (PAT is introduced. It overcomes the main problems of most state-of-the-art photoacoustic imaging approaches that are long acquisition times and the requirement of acoustic contact. In order to increase the acquisition speed significantly, the surface displacements of the object, caused by the photoacoustic pressure waves, are measured interferometrically in two dimensions. Phase alterations in the observed speckle field are used to identify changes in the object’s topography. A sampling rate of up to 80 MHz is feasible, which reduces the occurrence of motion artefacts.

  10. Marginal microleakage in vitro study on class V cavities prepared with Er:YAG laser and etched with acid or etched with Er:YAG laser and acid; Estudo in vitro da microinfiltracao marginal em cavidades classe V preparadas com laser de Er:YAG e condicionadas com acido ou com laser de Er:YAG e acido

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, Henrique Dutra Simoes

    2001-07-01

    Microleakage at the interface between the teeth and the restorative materials remains a problem with composite resin restorations. Microleakage at the gingival margins of class V cavities restorations still challenge as they are usually placed in dentin and/or cementum. Previous studies have shown that the cavity preparation with Er:YAG laser is possible. It has been reported that Er:YAG laser has ability to create irregular surface providing micromechanical retention for adhesive dental restorative materials and to improve marginal sealing. The purpose of this in vitro study was to evaluate the marginal microleakage on class V cavities prepared with Er:YAG laser and etched with acid or with Er:YAG laser and acid, in compared to those prepared and etched conventionally. Thirty human molars were divided into three groups, namely: group I - prepared with Er:YAG laser (KaVo KEY Laser II - Germany) and etched with 37% phosphoric acid; group II - prepared with Er:YAG laser and etched with Er:YAG laser and 37% phosphoric acid; group III (control group) - prepared with high speed drill and etched with 37% phosphoric acid. All cavities were treated with same adhesive system (Single Bond - 3M) and restored with the composite resin (Z100 - 3M), according to the manufacturer's instructions. The specimens were stored at 37 deg C in water for 24 hours, polished with Sof-Lex discs (3M), thermally stressed, sealed with a nail polish coating except for the area of the restoration and 1 mm around it, and immersed in a 50% aqueous solution of silver nitrate for 24 hours. After that, the specimens were rinsed in water, soaked in a photodeveloping solution and exposed to a fluorescent light for 8 hours. The teeth were embedded in an autopolymerizing resin and sectioned longitudinally using a diamond saw microtome under running water. The sections were photographed. The microleakage at the occlusal cavity and at the gingival margins of each specimen was evaluated with scores (0-3) by

  11. Morphological change study on root surfaces treated with curettes, sonic instruments or Er:YAG laser

    International Nuclear Information System (INIS)

    Guimaraes Filho, Arlindo Lopes

    2004-01-01

    Periodontal disease is caused by dental plaque and dental calculus on roots surfaces, specially on cervical areas. As dental plaque is the main cause and dental calculus a secondary one, it is practically impossible to separate one factor to the other one. In order to get periodontal tissue health it is necessary to eliminate dental plaque and calculus from root surfaces. In this sense, Er:YAG laser comes in as an excellent way to control periodontal disease, not only, by removing calculus and dental plaque but also for its bacteria reduction. The aim of this study is to compare, by S.E.M., root surfaces changing when they are treated with curettes and ultrasonic scaling or Er:YAG laser irradiation with two different energy levels of 60 mJ/pulse and 100 mJ/pulse and repetition tax of 10 Hz (in the display). It is also objective of this study to check a possible thermic damage to pulp tissue when the roots surfaces are irradiated with Er:YAG laser. We used for this study, five human dental roots, each one of them were cut into four samples, giving us a total of twenty samples, which were divided in five groups of four samples each one. The control group, we did not indicated any kind of treatment. The first group, the roots samples were scaled and planned with Gracey curettes 5/6 and 7/8. The second group, the roots samples were treated with ultrasonic instruments. The third group was irradiated with Er:YAG laser using 60 mJ/pulse , 10 Hz and energy density of 4 J/cm 2 (approximated). The fourth group was irradiated with Er:YAG laser using 100 mJ/pulse, 10 Hz and energy density of 7 J/cm 2 (approximated). The results analysis showed that roots scaling either with Gracey curettes or with ultrasonic instruments created smear layer covering roots surfaces; roots surfaces irradiated with Er:YAG laser showed few roughness in the third group; roots surfaces irradiated with Er:YAG laser showed no smear layer and the Er:YAG laser irradiation did not bring any thermic damage

  12. 885-nm laser diode array pumped ceramic Nd:YAG master oscillator power amplifier system

    Science.gov (United States)

    Yu, Anthony W.; Li, Steven X.; Stephen, Mark A.; Seas, Antonios; Troupaki, Elisavet; Vasilyev, Aleksey; Conley, Heather; Filemyr, Tim; Kirchner, Cynthia; Rosanova, Alberto

    2010-04-01

    The objective of this effort is to develop more reliable, higher efficiency diode pumped Nd:YAG laser systems for space applications by leveraging technology investments from the DoD and other commercial industries. Our goal is to design, build, test and demonstrate the effectiveness of combining 885 nm laser pump diodes and the use of ceramic Nd:YAG for future flight missions. The significant reduction in thermal loading on the gain medium by the use of 885 nm pump lasers will improve system efficiency.

  13. Diode-pumped continuous-wave eye-safe Nd:YAG laser at 1415 nm.

    Science.gov (United States)

    Lee, Hee Chul; Byeon, Sung Ug; Lukashev, Alexei

    2012-04-01

    We describe the output performance of the 1415 nm emission in Nd:YAG in a plane-concave cavity under traditional pumping into the 4F5/2 level (808 nm) and direct in-band pumping into the 4F3/2 level (885 nm). An end-pumped Nd:YAG laser yielded maximum cw output power of 6.3 W and 4.2 W at 885 nm and 808 nm laser diode (LD) pumping, respectively. To the best of our knowledge, this is the highest output power of a LD-pumped 1415 nm laser.

  14. Characterization of Stone Cleaning by Nd:YAG Lasers with Different Pulse Duration

    International Nuclear Information System (INIS)

    Bartoli, L.; Siano, S.; Salimbeni, R.; Pouli, P.; Fotakis, C.

    2006-01-01

    The present work is a comparative study on the laser cleaning of stonework using Nd:YAG lasers at different pulse durations. The ablation rate, the degree of cleaning, and the appearance of the treated surface were studied irradiating a simulated sample and a real stone artefact using three different Nd:YAG laser systems with pulse duration of 90 microseconds, 15 nanoseconds, and 150 picoseconds. To our knowledge, the picosecond laser is here used for the first time in stone conservation. Differences in efficiency and in cleaning result are shown and discussed.

  15. Nd-YAG laser treatment in a patient with complicated pilonidal cysts

    DEFF Research Database (Denmark)

    Lindholt, Christine S; Lindholt, Jes S.; Lindholt, Jan

    2009-01-01

    A 38-year-old woman with a recurrent suppurative pilonidal cyst was successfully treated causally with an Nd-YAG (neodymium-doped yttrium aluminium garnet) laser, and with no recurrence at 3-month follow-up. A similar success was observed for another 15 consecutively treated patients, including...... suppurative cases. The effect could be attributable to the ability of the YAG laser to operate at a wavelength of 1064 nm and to penetrate the skin to levels deeper than that of most other lasers before the energy is absorbed in melanin and oxyhaemoglobin. Consequently, the contents of the cyst can be reached...

  16. Marginal microleakage in vitro study on class V cavities prepared with Er:YAG laser and etched with acid or etched with Er:YAG laser and acid; Estudo in vitro da microinfiltracao marginal em cavidades classe V preparadas com laser de Er:YAG e condicionadas com acido ou com laser de Er:YAG e acido

    Energy Technology Data Exchange (ETDEWEB)

    Tavares, Henrique Dutra Simoes

    2001-07-01

    Microleakage at the interface between the teeth and the restorative materials remains a problem with composite resin restorations. Microleakage at the gingival margins of class V cavities restorations still challenge as they are usually placed in dentin and/or cementum. Previous studies have shown that the cavity preparation with Er:YAG laser is possible. It has been reported that Er:YAG laser has ability to create irregular surface providing micromechanical retention for adhesive dental restorative materials and to improve marginal sealing. The purpose of this in vitro study was to evaluate the marginal microleakage on class V cavities prepared with Er:YAG laser and etched with acid or with Er:YAG laser and acid, in compared to those prepared and etched conventionally. Thirty human molars were divided into three groups, namely: group I - prepared with Er:YAG laser (KaVo KEY Laser II - Germany) and etched with 37% phosphoric acid; group II - prepared with Er:YAG laser and etched with Er:YAG laser and 37% phosphoric acid; group III (control group) - prepared with high speed drill and etched with 37% phosphoric acid. All cavities were treated with same adhesive system (Single Bond - 3M) and restored with the composite resin (Z100 - 3M), according to the manufacturer's instructions. The specimens were stored at 37 deg C in water for 24 hours, polished with Sof-Lex discs (3M), thermally stressed, sealed with a nail polish coating except for the area of the restoration and 1 mm around it, and immersed in a 50% aqueous solution of silver nitrate for 24 hours. After that, the specimens were rinsed in water, soaked in a photodeveloping solution and exposed to a fluorescent light for 8 hours. The teeth were embedded in an autopolymerizing resin and sectioned longitudinally using a diamond saw microtome under running water. The sections were photographed. The microleakage at the occlusal cavity and at the gingival margins of each specimen was evaluated with scores (0

  17. Effects of a pulsed Nd:YAG laser on enamel and dentin

    Science.gov (United States)

    Myers, Terry D.

    1990-06-01

    Enamel and dentin samples were exposed extraorally to a pulsed neodymium yttriuma1uminumgarnet (Nd:YAG) laser. The lased samples were observed using both scanning electron microscopy and histological techniques to determine the effects of the laser. The present study has provided the following points: (1) Properly treated, enamel can be 1aser etched to a depth comparable to that achieved with phosphoric acid etching; and (2) both carious and noncarious dentin can be vaporized by the Nd:YAG laser. No cracking or chipping of any enamel or dentin sample was observed histologically or under the SEM.

  18. Aluminium alloys welding with high-power Nd:YAG lasers

    International Nuclear Information System (INIS)

    Garcia Orza, J.A.

    1998-01-01

    Aluminium alloys have good mechanical properties (high strength-to-weight ratio, corrosion resistance) and good workability. their applications are growing up, specially in the transportation industry. Weldability is however poorer than in other materials; recent advances in high power YAG laser are the key to obtain good appearance welds and higher penetration, at industrial production rates. Results of the combination of high power YAG beams with small fiber diameters and specific filler wires are presented. It is also characterized the air bone particulate material, by-product of the laser process: emission rates, size distribution and chemical composition are given for several aluminium alloys. (Author) 6 refs

  19. Imaging contrast and tip-sample interaction of non-contact amplitude modulation atomic force microscopy with Q -control

    International Nuclear Information System (INIS)

    Shi, Shuai; Guo, Dan; Luo, Jianbin

    2017-01-01

    Active quality factor ( Q ) exhibits many promising properties in dynamic atomic force microscopy. Energy dissipation and image contrasts are investigated in the non-contact amplitude modulation atomic force microscopy (AM-AFM) with an active Q -control circuit in the ambient air environment. Dissipated power and virial were calculated to compare the highly nonlinear interaction of tip-sample and image contrasts with different Q gain values. Greater free amplitudes and lower effective Q values show better contrasts for the same setpoint ratio. Active quality factor also can be employed to change tip-sample interaction force in non-contact regime. It is meaningful that non-destructive and better contrast images can be realized in non-contact AM-AFM by applying an active Q -control to the dynamic system. (paper)

  20. 经皮肾穿刺钬激光碎石术后疼痛的护理干预%Nursing intervention of postoperative pain after percutaneous nephrolithotomy holmium laser

    Institute of Scientific and Technical Information of China (English)

    白玫; 乔够梅; 杏玲芝; 陆皓

    2012-01-01

    目的:探讨护理干预对减轻经皮肾穿刺钬激光碎石术后疼痛的效果.方法:随机将264例经皮肾穿刺钬激光碎石术患者分成干预组和对照组各132例.对照组患者给予经皮肾穿刺钬激光碎石术后常规护理,干预组在对照组的基础上进行一系列的护理干预.结果:干预组术后疼痛明显低于对照组(P<0.05).结论:护理干预在经皮肾穿刺钬激光碎石术后应用能明显减轻患者疼痛,加速患者术后康复,有利于护理质量的提高.%Objective:To study the nursing intervention on reducing percutaneous holmium laser effect of postoperative pain. Methods:264 patients randomized to percutaneous nephrolithotomy with holmium laser lithotripsy were divided into intervention group and control group of 132 cases at radom. The control group conventional percutaneous holmium laser lithotripsy postoperative care, intervention group were based on a series of nursing intervention. Results postoperative pain of intervention group was significantly lower than control group ( P <0.05 ). Conclusion: Nursing intervention in percutaneous holmium laser lithotripsy in patients with significantly reduced postoperative pain,accelerated postoperative recovery, is conducive to improving quality of care.

  1. Transition of Emission Colours as a Consequence of Heat-Treatment of Carbon Coated Ce3+-Doped YAG Phosphors

    Directory of Open Access Journals (Sweden)

    Liang-Jun Yin

    2017-10-01

    Full Text Available To modify the luminescence properties of Ce3+-doped Y3Al5O12 (YAG phosphors, they have been coated with a carbon layer by chemical vapor deposition and subsequently heat-treated at high temperature under N2 atmosphere. Luminescence of the carbon coated YAG:Ce3+ phosphors has been investigated as a function of heat-treatment at 1500 and 1650 °C. The 540 nm emission intensity of C@YAG:Ce3+ is the highest when heated at 1650 °C, while a blue emission at 400–420 nm is observed when heated at 1500 °C but not at 1650 °C. It is verified by X-ray diffraction (XRD that the intriguing luminescence changes are induced by the formation of new phases in C@YAG:Ce3+-1500 °C, which disappear in C@YAG:Ce3+-1650 °C. In order to understand the mechanisms responsible for the enhancement of YAG:Ce3+ emission and the presence of the blue emission observed for C@YAG:Ce3+-1500 °C, the samples have been investigated by a combination of several electron microscopy techniques, such as HRTEM, SEM-CL, and SEM-EDS. This local and cross-sectional analysis clearly reveals a gradual transformation of phase and morphology in heated C@YAG:Ce3+ phosphors, which is related to a reaction between C and YAG:Ce3+ in N2 atmosphere. Through reaction between the carbon layer and YAG host materials, the emission colour of the phosphors can be modified from yellow, white, and then back to yellow under UV excitation as a function of heat-treatment in N2 atmosphere.

  2. Transition of Emission Colours as a Consequence of Heat-Treatment of Carbon Coated Ce3+-Doped YAG Phosphors.

    Science.gov (United States)

    Yin, Liang-Jun; Dierre, Benjamin; Sekiguchi, Takashi; van Ommen, J Ruud; Hintzen, Hubertus T Bert; Cho, Yujin

    2017-10-16

    To modify the luminescence properties of Ce 3+ -doped Y₃Al₅O 12 (YAG) phosphors, they have been coated with a carbon layer by chemical vapor deposition and subsequently heat-treated at high temperature under N₂ atmosphere. Luminescence of the carbon coated YAG:Ce 3+ phosphors has been investigated as a function of heat-treatment at 1500 and 1650 °C. The 540 nm emission intensity of C@YAG:Ce 3+ is the highest when heated at 1650 °C, while a blue emission at 400-420 nm is observed when heated at 1500 °C but not at 1650 °C. It is verified by X-ray diffraction (XRD) that the intriguing luminescence changes are induced by the formation of new phases in C@YAG:Ce 3+ -1500 °C, which disappear in C@YAG:Ce 3+ -1650 °C. In order to understand the mechanisms responsible for the enhancement of YAG:Ce 3+ emission and the presence of the blue emission observed for C@YAG:Ce 3+ -1500 °C, the samples have been investigated by a combination of several electron microscopy techniques, such as HRTEM, SEM-CL, and SEM-EDS. This local and cross-sectional analysis clearly reveals a gradual transformation of phase and morphology in heated C@YAG:Ce 3+ phosphors, which is related to a reaction between C and YAG:Ce 3+ in N₂ atmosphere. Through reaction between the carbon layer and YAG host materials, the emission colour of the phosphors can be modified from yellow, white, and then back to yellow under UV excitation as a function of heat-treatment in N₂ atmosphere.

  3. Comparison of intraocular pressure measurement between rebound, non-contact and Goldmann applanation tonometry in treated glaucoma patients.

    Science.gov (United States)

    Vincent, Stephen J; Vincent, Roslyn A; Shields, David; Lee, Graham A

    2012-01-01

    To compare the intraocular pressure readings obtained with the iCare rebound tonometer and the 7CR non-contact tonometer with those measured by Goldmann applanation tonometry in treated glaucoma patients. A prospective, cross-sectional study was conducted in a private tertiary glaucoma clinic. One hundred nine (54 males : 55 females) patients including only eyes under medical treatment for glaucoma. Measurement by Goldmann applanation tonometry, iCare rebound tonometry and 7CR non-contact tonometry. Intraocular pressure. There were strong correlations between the intraocular pressure measurements obtained with Goldmann and both the rebound and non-contact tonometers (Spearman r-values ≥ 0.79, P tonometer. For the rebound tonometer, the mean intraocular pressure was slightly higher compared with the Goldmann applanation tonometer in the right eyes (P = 0.02), and similar in the left eyes (P = 0.93); however, these differences did not reach statistical significance. The Goldmann correlated measurements from the non-contact tonometer were lower than the average Goldmann reading for both right (P 0.01) eyes. The corneal compensated measurements from the non-contact tonometer were significantly higher compared with the other tonometers (P ≤ 0.001). The iCare rebound tonometer and the 7CR non-contact tonometer measure intraocular pressure in fundamentally different ways to the Goldmann applanation tonometer. The resulting intraocular pressure values vary between the instruments and will need to be considered when comparing clinical versus home acquired measurements. © 2011 The Authors. Clinical and Experimental Ophthalmology © 2011 Royal Australian and New Zealand College of Ophthalmologists.

  4. SPF-RR sequential photothermal fractional resurfacing and remodeling with the variable pulse Er:YAG laser and scanner-assisted Nd:YAG laser.

    Science.gov (United States)

    Marini, Leonardo

    2009-12-01

    Many different lasers, polychromatic high-intensity light sources (PCLs), and RF devices have claimed clinical efficacy in rejuvenating the skin. In this study, the sequential combination of two different laser wavelengths was evaluated to produce reliably significant clinical improvements optimizing treatment parameters. The left volar aspects of the forearms of four volunteers were treated with nine different parameter settings using a variable pulsewidth fractional Er:YAG 2940-nm laser with and without air cooling. The pain perception level was recorded on a 0-10 point scale (0=No pain; 10=Most severe pain). Three evaluations were made: during treatment, immediately after treatment, and 5 minutes after treatment. The same investigation was made on the right volar aspects of the same four volunteers using a short-pulse, random pattern, 3-mm spot, scanner-assisted Nd-YAG 1064-nm laser at 0.3 ms pulsewidth at seven different parameter settings. Clinical evaluations were made concerning erythema and edema 3 days after treatment, as well as pre-operative and 60 days postoperative skin texture plus color uniformity. Considering that the majority of cosmetic patients are willing to accept a relatively short and uneventful downtime (2-4 days according to a study we are presently conducting) and do prefer to limit their intra- and postoperative pain to a minimum, the best combination of clinical improvement matching these two important parameters were selected for our study. A treatment strategy combining two sequential passes of long-pulse Nd:YAG laser (Nd:YAG-LP) at 0.3 and 35 ms followed by two passes of long-pulse fractional Er:YAG laser (Er:YAG-FT) at 600 micros was designed to treat the facial regions of 10 volunteers affected by a combination of intrinsic (chrono-) and extrinsic (mostly photo-) aging. The pain perception level was recorded on a 0-10 scale (0=No pain; 10=Most severe pain). Three evaluations were made: during, immediately after, and 5 minutes after

  5. UNS S32750 super duplex steel welding using pulsed Nd:YAG laser; Soldagem do aco superduplex UNS S32750 com laser pulsado Nd:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Francini, O.D.; Andrade, G.G.; Clemente, M.S.; Gallego, J.; Ventrella, V.A., E-mail: ventrella@dem.feis.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Ilha Solteira, SP (Brazil). Departamento de Engenharia Mecanica

    2016-07-01

    Laser is a flexible and powerful tool with many relevant applications in industry, mainly in the welding area. Lasers today provide the welding industry technical solutions to many problems. This work studied the weld metal obtained by pulsed laser welding of Nd: YAG super duplex stainless steel UNS S32750 employed in the oil and natural gas, analyzing the influence of high cooling rate, due to the laser process, the swing phase ferrite / austenite. Were performed weld beads in butt joint with different repetition rates. The different microstructures were obtained by optical microscopy and scanning electron microscopy. The results showed that the effect of varying the welding energy of Nd: YAG laser on the volume fractions of the phases ferrite/austenite in the weld metal was its ferritization and low austenite amount on the grain boundary. (author)

  6. Incidence of open-angle glaucoma and screening of the intraocular pressure with a non-contact tonometer.

    Science.gov (United States)

    Rouhiainen, H; Teräsvirta, M

    1990-06-01

    New equipment for measuring intraocular pressure have been introduced lately. One of these is the Keeler Pulsair non-contact tonometer which uses pressurized air in measurement. It is found to be safe and easy to use in practice, but it seems to give 1.5-2.0 mmHg lower reading than the Goldmann applanation tonometer. This was confirmed by the present study, where non-contact tonometry was controlled by applanation tonometry with a 2-3 week delay between the measurements. However, for screening procedures the accuracy of the apparatus can be considered as sufficient.

  7. Dynamic torsional response analysis of mechanoluminescent paint and its application to non-contacting automotive torque transducers

    International Nuclear Information System (INIS)

    Kim, Gi-Woo; Kim, Ji-Sik

    2014-01-01

    This paper presents the result of a preliminary experimental study on the dynamic torsional response analysis of mechanoluminescent (ML) paint for potential development as a new type of non-contacting torque transducer. The torsional torque applied to a transmission shaft is measured by sensing the ML intensity emitting from an ML paint coating a transmission shaft. This study provides the fundamental knowledge for the development of new non-contacting torque sensing technology based on the ML intensity detection. The proposed measurement principle appears to offer potential applications in automotive torque measurement systems, even though the loading rate-dependent characteristics of the ML intensity needs to be examined further. (paper)

  8. Dynamic torsional response analysis of mechanoluminescent paint and its application to non-contacting automotive torque transducers

    Science.gov (United States)

    Kim, Gi-Woo; Kim, Ji-Sik

    2014-01-01

    This paper presents the result of a preliminary experimental study on the dynamic torsional response analysis of mechanoluminescent (ML) paint for potential development as a new type of non-contacting torque transducer. The torsional torque applied to a transmission shaft is measured by sensing the ML intensity emitting from an ML paint coating a transmission shaft. This study provides the fundamental knowledge for the development of new non-contacting torque sensing technology based on the ML intensity detection. The proposed measurement principle appears to offer potential applications in automotive torque measurement systems, even though the loading rate-dependent characteristics of the ML intensity needs to be examined further.

  9. 1.8kW laser diode pumped YAG laser; Shutsuryoku 1.8kW no handotai laser reiki YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Toshiba Corporation, as a participant in Ministry of International Trade and Industry`s `photon measurement and processing technology project` since August, 1997, is engaged in the development of an energy-efficient LD (laser diode) pumped semiconductor YAG (yttrium-aluminum-garnet) laser device to be used for welding and cutting. It is a 5-year project and the goal is a mean output of 10kW and efficiency of 20%. In this article, a simulation program is developed which carries out calculation about element technology items such as the tracking of the beam from the pumping LD and the excitation distribution, temperature distribution, thermal stress distribution, etc., in the YAG rod. An oscillator is constructed, based on the results of the simulation, and it exhibits a world-high class continuous laser performance of a 1.8kW output and 13% efficiency. The record of 13% efficiency is five times higher than that achieved by the conventional lamp-driven YAG laser device. (translated by NEDO)

  10. Influence of Er:YAG and Nd:YAG wavelengths on laser-induced breakdown spectroscopy measurements under air or helium atmosphere

    International Nuclear Information System (INIS)

    Detalle, Vincent; Sabsabi, Mohamad; St-Onge, Louis; Hamel, Andre; Heon, Rene

    2003-01-01

    Laser-induced breakdown spectroscopy (LIBS) is widely dependent on the conditions of its implementation in terms of laser characteristics (wavelength, energy, and pulse duration), focusing conditions, and surrounding gas. In this study two wavelengths, 1.06 and 2.94 μm, obtained with Nd:YAG and Er:YAG lasers, respectively, were used for LIBS analysis of aluminum alloy samples in two conditions of surrounding gas. The influence of the laser wavelength on the laser-produced plasma was studied for the same irradiance by use of air or helium as a buffer gas at atmospheric pressure. We used measurements of light emission to determine the temporally resolved space-averaged electron density and plasma temperature in the laser-induced plasma. We also examined the effect of laser wavelength in two different ambient conditions in terms of spectrochemical analysis by LIBS. The results indicate that the effect of the surrounding gas depends on the laser wavelength and the use of an Er:YAG laser could increase linearity by limiting the leveling in the calibration curve for some elements in aluminum alloys. There is also a significant difference between the plasma induced by the two lasers in terms of electron density and plasma temperature

  11. Proposal of Non-Contact Type Interface of Command Input Using Lip Motion Features

    Science.gov (United States)

    Sato, Yoshiyuki; Kageyama, Yoichi; Nishida, Makoto

    Lip motion features are of practical use in identifying individuals. It is therefore important to develop non-contact type interface. For the interface using lip motion features, individual differences such as accents and dialects in commands should be accepted. In this paper, we propose a method to identify commands by analyzing three kinds of lip motion features. They are lip width, lip length, and ratio of width and length. The analysis is made on the basis of these features' relative values obtained from the primary and object frame. The proposed method has three steps. First, we extracted the lip motion features on the basis of both positions and shapes of lip in each frame of facial images. Second, standard patterns were created from features of six utterances per command. The standard pattern is able to reduce the relative difference in the lip motion features. Third, similarities among commands were computed by Dynamic-Programming (DP) matching. And then, the command with the largest similarity was selected as the target one. Our experimental results suggest that proposed method is useful to construct the non-contact type interface of command input using lip motion features.

  12. Noncontact blood species identification method based on spatially resolved near-infrared transmission spectroscopy

    Science.gov (United States)

    Zhang, Linna; Sun, Meixiu; Wang, Zhennan; Li, Hongxiao; Li, Yingxin; Li, Gang; Lin, Ling

    2017-09-01

    The inspection and identification of whole blood are crucially significant for import-export ports and inspection and quarantine departments. In our previous research, we proved Near-Infrared diffuse transmitted spectroscopy method was potential for noninvasively identifying three blood species, including macaque, human and mouse, with samples measured in the cuvettes. However, in open sampling cases, inspectors may be endangered by virulence factors in blood samples. In this paper, we explored the noncontact measurement for classification, with blood samples measured in the vacuum blood vessels. Spatially resolved near-infrared spectroscopy was used to improve the prediction accuracy. Results showed that the prediction accuracy of the model built with nine detection points was more than 90% in identification between all five species, including chicken, goat, macaque, pig and rat, far better than the performance of the model built with single-point spectra. The results fully supported the idea that spatially resolved near-infrared spectroscopy method can improve the prediction ability, and demonstrated the feasibility of this method for noncontact blood species identification in practical applications.

  13. Phenomenological modeling of long range noncontact friction in micro- and nanoresonators

    International Nuclear Information System (INIS)

    Gusso, Andre

    2011-01-01

    Motivated by the results of an experiment using atomic force microscopy performed by Gotsmann and Fuchs [Phys. Rev. Lett. 86, 2597 (2001)], where a strong energy loss due to the tip-sample interaction was measured, we investigate the potential implications of this energy loss channel to the quality factor of suspended micro- and nanoresonators. Because the observed tip-sample dissipation remains without a satisfactory theoretical explanation, two phenomenological models are proposed to generalize the experimental observations. In the minimal phenomenological model the range of validity of the power law found experimentally for the damping coefficient is assumed to be valid for larger separations. A more elaborate phenomenological model assumes that the noncontact friction is a consequence of the Casimir force acting between the closely spaced surfaces. Both models provide quantitative results for the noncontact friction between any two objects which are then used to estimate the energy loss for suspended bar micro- and nanoresonators. It is concluded that the energy loss due to the unknown mechanism has the potential to seriously restrict the quality factor of both micro- and nanoresonators.

  14. Image-based non-contact monitoring of skin texture changed by piloerection for emotion estimation

    Science.gov (United States)

    Uchida, Mihiro; Akaho, Rina; Ogawa, Keiko; Tsumura, Norimichi

    2018-02-01

    In this paper, we find the effective feature values of skin textures captured by non-contact camera to monitor piloerection on the skin for emotion estimation. Recently, emotion estimation is required for service robots to interact with human more naturally. There are a lot of researches of estimating emotion and additional methods are required to improve emotion estimation because using only a few methods may not give enough information for emotion estimation. In the previous study, it is necessary to fix a device on the subject's arm for detecting piloerection, but the contact monitoring can be stress itself and distract the subject from concentrating in the stimuli and evoking strong emotion. So, we focused on the piloerection as the object obtained with non-contact methods. The piloerection is observed as goose bumps on the skin when the subject is emotionally moved, scared and so on. This phenomenon is caused by contraction of arrector pili muscles with the activation of sympathetic nervous system. This piloerection changes skin texture. Skin texture is important in the cosmetic industry to evaluate skin condition. Therefore, we thought that it will be effective to evaluate the condition of skin texture for emotion estimation. The evaluations were performed by extracting the effective feature values from skin textures captured with a high resolution camera. The effective feature values should have high correlation with the degree of piloerection. In this paper, we found that standard deviation of short-line inclination angles in the texture is well correlated with the degree of piloerection.

  15. A Case of Non-Contact Lens related Acanthamoeba keratitis in Malaysia

    Directory of Open Access Journals (Sweden)

    Mohamed Kamel, A. G.

    2005-01-01

    Full Text Available Acanthamoeba is a ubiquitous free-living amoeba and is responsible for an uncommon yet increasingly diagnosed keratitis in humans. Acanthamoeba keratitis is perhaps the most challenging ocular infection to manage successfully and it can result in permanently impaired vision or blindness. Although contact lens use is the principal risk factor, about 10% of cases occur following trauma and exposure to contaminated soil or water. Cases of Acanthamoeba keratitis involving contact lens wearers have previously been reported in Malaysia but this is the first time, a non-contact lens relatedAcanthamoeba keratitis is reported. The case involved a 28 year old Indonesian male construction worker who had a trauma of the right eye. While working his eye was struck by some sand and dust particles and he quickly washed his eye with water from an open tank at the construction site. He then experienced pain, redness, glaring and blurring of vision of the right eye. The diagnosis was missed at the initial presentation but subsequent culture of the corneal scraping demonstrated Acanthamoeba as the aetiological agent. The history, clinical findings, diagnosis and treatment of non-contact lens related Acanthamoeba keratitis are briefly discussed in this communication. We hope to create awareness especially among the medical and paramedical staff about the existence of this infection in the country and fully support the consideration of Acanthamoeba keratitis as part of the differential diagnosis of most cases of presumed microbial keratitis.

  16. Non-contact assessment of obstructive sleep apnea cardiovascular biomarkers using photoplethysmography imaging

    Science.gov (United States)

    Amelard, Robert; Pfisterer, Kaylen J.; Jagani, Shubh; Clausi, David A.; Wong, Alexander

    2018-02-01

    Obstructive sleep apnea (OSA) affects 20% of the adult population, and is associated with cardiovascular and cognitive morbidities. However, it is estimated that up to 80% of treatable OSA cases remain undiagnosed. Cur- rent methods for diagnosing OSA are expensive, labor-intensive, and involve uncomfortable wearable sensors. This study explored the feasibility of non-contact biophotonic assessment of OSA cardiovascular biomarkers via photoplethysmography imaging (PPGI). In particular, PPGI was used to monitor the hemodynamic response to obstructive respiratory events. Sleep apnea onset was simulated using Muller's maneuver in which breathing was obstructed by a respiratory clamp. A custom PPGI system, coded hemodynamic imaging (CHI), was positioned 1 m above the bed and illuminated the participant's head with 850 nm light, providing non-intrusive illumination for night-time monitoring. A video was recorded before, during and following an apnea event at 60 fps, yielding 17 ms temporal resolution. Per-pixel absorbance signals were extracted using a Beer-Lambert derived light transport model, and subsequently denoised. The extracted hemodynamic signal exhibited dynamic temporal modulation during and following the apnea event. In particular, the pulse wave amplitude (PWA) decreased during obstructed breathing, indicating vasoconstriction. Upon successful inhalation, the PWA gradually increased toward homeostasis following a temporal phase delay. This temporal vascular tone modulation provides insight into autonomic and vascular response, and may be used to assess sleep apnea using non-contact biophotonic imaging.

  17. Non-contact assessment of electrical performance for rapidly sintered nanoparticle silver coatings through colorimetry

    International Nuclear Information System (INIS)

    Cherrington, M.; Claypole, T.C.; Gethin, D.T.; Worsley, D.A.; Deganello, D.

    2012-01-01

    The color change during the ultrafast near-infrared sintering process of a nanoparticle silver ink has been correlated to its electrical performance through colorimetry using the CIELAB industry standard. Nanoparticle silver ink films, deposited over a flexible polyethylene terephthalate substrate, presented significant shifting in the a* and b* color coordinates during sintering, exhibiting the best conductivity with an a* coordinate of approximately 0 and a b* coordinate of approximately + 10. This color change has been associated with the Lorenz–Mie theory of electromagnetic scattering. This indirect measurement technique is potentially a breakthrough technology for fast in-line non-contact characterization of the drying and sintering process of nanoparticle conductive inks for use in large area roll-to-roll processing of printed electronics. - Highlights: ► Color change of a nanoparticle silver coating was measured during sintering ► Color change was correlated to the electrical performance of the coating. ► Potential in-line non-contact measurement method for roll-to-roll printed electronics

  18. Non-contact assessment of electrical performance for rapidly sintered nanoparticle silver coatings through colorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cherrington, M.; Claypole, T.C.; Gethin, D.T. [Welsh Centre for Printing and Coating, College of Engineering, Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom); Worsley, D.A. [SPECIFIC, College of Engineering, Swansea University, Baglan Bay Innovation Centre, Central Avenue, Baglan Energy Park, Port Talbot, SA12 7AX (United Kingdom); Deganello, D., E-mail: d.deganello@swansea.ac.uk [Welsh Centre for Printing and Coating, College of Engineering, Swansea University, Singleton Park, Swansea, SA2 8PP (United Kingdom)

    2012-11-01

    The color change during the ultrafast near-infrared sintering process of a nanoparticle silver ink has been correlated to its electrical performance through colorimetry using the CIELAB industry standard. Nanoparticle silver ink films, deposited over a flexible polyethylene terephthalate substrate, presented significant shifting in the a* and b* color coordinates during sintering, exhibiting the best conductivity with an a* coordinate of approximately 0 and a b* coordinate of approximately + 10. This color change has been associated with the Lorenz-Mie theory of electromagnetic scattering. This indirect measurement technique is potentially a breakthrough technology for fast in-line non-contact characterization of the drying and sintering process of nanoparticle conductive inks for use in large area roll-to-roll processing of printed electronics. - Highlights: Black-Right-Pointing-Pointer Color change of a nanoparticle silver coating was measured during sintering Black-Right-Pointing-Pointer Color change was correlated to the electrical performance of the coating. Black-Right-Pointing-Pointer Potential in-line non-contact measurement method for roll-to-roll printed electronics.

  19. Non-Contact Smartphone-Based Monitoring of Thermally Stressed Structures

    Science.gov (United States)

    Ozturk, Turgut; Mas, David; Rizzo, Piervincenzo

    2018-01-01

    The in-situ measurement of thermal stress in beams or continuous welded rails may prevent structural anomalies such as buckling. This study proposed a non-contact monitoring/inspection approach based on the use of a smartphone and a computer vision algorithm to estimate the vibrating characteristics of beams subjected to thermal stress. It is hypothesized that the vibration of a beam can be captured using a smartphone operating at frame rates higher than conventional 30 Hz, and the first few natural frequencies of the beam can be extracted using a computer vision algorithm. In this study, the first mode of vibration was considered and compared to the information obtained with a conventional accelerometer attached to the two structures investigated, namely a thin beam and a thick beam. The results show excellent agreement between the conventional contact method and the non-contact sensing approach proposed here. In the future, these findings may be used to develop a monitoring/inspection smartphone application to assess the axial stress of slender structures, to predict the neutral temperature of continuous welded rails, or to prevent thermal buckling. PMID:29670034

  20. A non-contact time-domain scanning brain imaging system: first in-vivo results

    Science.gov (United States)

    Mazurenka, M.; Di Sieno, L.; Boso, G.; Contini, D.; Pifferi, A.; Dalla Mora, A.; Tosi, A.; Wabnitz, H.; Macdonald, R.

    2013-06-01

    We present results of first in-vivo tests of an optical non-contact scanning imaging system, intended to study oxidative metabolism related processes in biological tissue by means of time-resolved near-infrared spectroscopy. Our method is a novel realization of the short source-detector separation approach and based on a fast-gated single-photon avalanche diode to detect late photons only. The scanning system is built in quasi-confocal configuration and utilizes polarizationsensitive detection. It scans an area of 4×4 cm2, recording images with 32×32 pixels, thus creating a high density of source-detector pairs. To test the system we performed a range of in vivo measurements of hemodynamic changes in several types of biological tissues, i.e. skin (Valsalva maneuver), muscle (venous and arterial occlusions) and brain (motor and cognitive tasks). Task-related changes in hemoglobin concentrations were clearly detected in skin and muscle. The brain activation shows weaker, but yet detectable changes. These changes were localized in pixels near the motor cortex area (C3). However, it was found that even very short hair substantially impairs the measurement. Thus the applicability of the scanner is limited to hairless parts of body. The results of our first in-vivo tests prove the feasibility of non-contact scanning imaging as a first step towards development of a prototype for biological tissue imaging for various medical applications.