Thulium laser urethrotomy for urethral stricture: a preliminary report.

PubMed

Wang, Linhui; Wang, Zhixiang; Yang, Bo; Yang, Qing; Sun, Yinghao

2010-09-01

The outcome of thulium laser urethrotomy for patients with urethral stricture had not been reported. The purpose of this study was to evaluate outcome of endourethrotomy with the thulium laser as a minimally invasive treatment for urethral stricture. Twenty-one consecutive patients with urethral stricture were evaluated by retrograde uroflowmetry, International Prostate Symptom Score (IPSS), and quality of life preoperatively at a single academic center. All patients were treated with thulium laser urethrotomy. All patients were followed up for 12-24 months postoperatively by uroflowmetry and by retrograde with voiding cystourethrogram every 3 months. And all patients were followed up by mailed questionnaire, including IPSS and quality of life. Retrograde endoscopic thulium laser urethrotomy was performed in all 21 patients. Most patients (N = 16; 76.2%) did not need any reintervention. Five patients developed recurrent strictures, of them two patients were treated by another laser urethrotomy, one patient was treated by open urethroplasty with buccal mucosa and the other two patients' reintervention were treated by urethral dilation. No intraoperative complications were encountered, although in 9.5% (N = 2) of patients, a urinary tract infection was diagnosed postoperatively. No gross hematuria occurred. Including two patients treated with repeat laser urethrotomy, 17(81.0%) showed good flow of urine (Q(ave)>16.0 ml/second) and adequate caliber urethra in retrograde urethrogram (RGU) 12 months after operation. Three (14.3%) patients showed narrow stream of urine (Q(ave)<8.0 ml/second) and urethral dilation was done every month or 2 months. There was one patient whose Q(ave) was between 8.0 and 16.0 ml/second. And this patient was treated by neither urethral dilation nor another laser urethrotomy. The thulium laser urethrotomy was a safe and effective minimally invasive therapeutic modality for urethral stricture. 2010 Wiley-Liss, Inc.

Enhanced performance of an S-band fiber laser using a thulium-doped photonic crystal fiber

NASA Astrophysics Data System (ADS)

Muhammad, A. R.; Emami, S. D.; Hmood, J. K.; Sayar, K.; Penny, R.; Abdul-Rashid, H. A.; Ahmad, H.; Harun, S. W.

2014-11-01

This work proposes a new method to enhance the performance of an S-band fiber laser by using a thulium-doped photonic crystal fiber (PCF). The proposed method is based on amplified spontaneous emission (ASE) suppression provided by the thulium-doped PCF unique geometric structure. The enhanced performance of this filter based PCF is dependent on the short and long cut-off wavelength characteristics that define the fiber transmission window. Realizing the short wavelength cut-off location requires the PCF cladding to be doped with a high index material, which provides a refractive index difference between the core and cladding region. Achieving the long cut-off wavelength necessitates enlarging the size of the air holes surrounding the rare-earth doped core region. The PCF structure is optimized so as to achieve the desired ASE suppression regions of below 0.8 μm and above 1.8 μm. The laser performance is simulated for different host media, namely pure silica, alumino-silicate, and fluoride-based fiber ZBLAN based on this thulium-doped PCF design. The host media spectroscopic details, including lifetime variations and quantum efficiency effect on the lasing emission are also discussed. Information on the filter based PCF design is gathered via a full-vectorial finite element method analysis and specifically a numerical modelling solution for the energy level rate equation using the Runge-Kutta method. Results are analyzed for gain improvement, lasing cavity, laser efficiency and effect of core size diameter variation. Results are compared with conventional thulium-doped fiber and thulium-doped PCF for every single host media. We observe that the ZBLAN host media is the most promising candidate due to its greater quantum efficiency.

Holmium:YAG (lambda=2120nm) vs. Thulium fiber (lambda=1908nm) laser for high-power vaporization of canine prostate tissue

NASA Astrophysics Data System (ADS)

Casperson, Andrew L.; Barton, Robert A.; Scott, Nicholas J.; Fried, Nathaniel M.

2008-02-01

Direct studies comparing different lasers for treatment of BPH are lacking. This preliminary study compares continuous-wave (CW) vs. pulsed prostate tissue vaporization for the Thulium fiber laser and Holmium:YAG laser, both operating near the 1940 nm water absorption peak in tissue. A 50-W Thulium fiber laser (λ= 1908 nm) delivered CW laser radiation through a 600-μm silica fiber in non-contact mode with a 5-mm-diameter spot at the tissue surface. A Holmium:YAG laser (λ= 2120 nm) operated with an energy of 2 J, pulse rate of 25 Hz, and average power of 50 W, and delivered pulsed laser radiation through a 600-μm silica fiber with a 5-mm-diameter laser spot to achieve similar irradiances at the tissue surface. Tissue vaporization was performed in air with the prostate kept hydrated in saline. Tissue vaporization efficiency of both lasers was compared (n = 10 canine prostates for each laser group). Mean vaporization efficiency measured 5.30 +/- 0.48 kJ/g vs. 4.13 +/- 0.46 kJ/g for Thulium fiber and Holmium lasers (P < 0.05). Tissue vaporization rates measured 0.57 +/- 0.05 g/min vs. 0.73 +/- 0.07 g/min (P < 0.05). The Holmium:YAG laser vaporizes prostate tissue at a higher rate than the Thulium fiber laser, for the same average power delivered to the tissue. Both the Thulium fiber laser and Holmium:YAG lasers are capable of vaporizing prostate tissue at a rate > 1 g/min if operated at the high powers (100-W) typically used in the clinic.

[Transurethral thulium laser urethrotomy for urethral stricture].

PubMed

Liu, Chun-Lai; Zhang, Xi-Ling; Liu, Yi-Li; Wang, Ping

2011-09-01

To evaluate the effect of endourethrotomy with thulium laser as a minimally invasive treatment for urethral stricture. We treated 36 cases of urethral stricture or atresia by endourethrotomy with thulium laser, restored the urethral continuity by vaporization excision of the scar tissue, and observed the clinical effects and complications. The mean operation time was 35 min, ranging from 10 to 90 min. Smooth urination was achieved after 2-6 weeks of catheter indwelling, with no urinary incontinence. The patients were followed up for 4-24 (mean 12) months, during which 27 did not need any reintervention, 5 developed urinary thinning but cured by urethral dilation, 3 received another laser urethrotomy for previous negligence of timely urethral dilation, and the other 1 underwent open urethroplasty. Thulium laser urethrotomy is a safe and effective minimally invasive option for short urethral stricture, which is also suitable for severe urethral stricture and urethral atresia. Its short-term outcome is satisfactory, but its long-term effect remains to be further observed.

Incisional effects of 1940 nm thulium fiber laser on oral soft tissues

NASA Astrophysics Data System (ADS)

Güney, Melike; Tunç, Burcu; Gülsoy, Murat

2013-02-01

Lasers of different wavelengths are being used in oral surgery for incision and excision purposes with minimal bleeding and pain. Among these wavelengths, those close to 2μ yield more desirable results on oral soft tissue due to their strong absorption by water. The emission of 1940 nm Thulium fiber laser is well absorbed by water which makes it a promising tool for oral soft tissue surgery. This study was conducted to investigate the potential of thulium fiber laser as an incisional and excisional oral surgical tool. Ovine tongue has been used as the target tissue due to its similarities to human oral tissues. Laser light obtained from a 1940 nm Thulium fiber laser was applied in contact mode onto ovine tongue completely submerged in saline solution in vitro, via a 600)μm fiber moved with a velocity of 0.5 mm /s to form incisions. There were a total of 9 groups determined by the power (2,5-3- 3,5 W), and number of passes (1-3-5). The samples were stained with HE for microscopic evaluation of depth of ablation and extent of coagulation. The depth of incisions produced with 1940 nm Thulium fiber laser increased with increasing power and number of passes, however an increase in the width of the coagulation zone was also observed.

High Power Q-Switched Thulium Doped Fibre Laser using Carbon Nanotube Polymer Composite Saturable Absorber

PubMed Central

Chernysheva, Maria; Mou, Chengbo; Arif, Raz; AlAraimi, Mohammed; Rümmeli, Mark; Turitsyn, Sergei; Rozhin, Aleksey

2016-01-01

We have proposed and demonstrated a Q-switched Thulium doped fibre laser (TDFL) with a ‘Yin-Yang’ all-fibre cavity scheme based on a combination of nonlinear optical loop mirror (NOLM) and nonlinear amplified loop mirror (NALM). Unidirectional lasing operation has been achieved without any intracavity isolator. By using a carbon nanotube polymer composite based saturable absorber (SA), we demonstrated the laser output power of ~197 mW and pulse energy of 1.7 μJ. To the best of our knowledge, this is the highest output power from a nanotube polymer composite SA based Q-switched Thulium doped fibre laser. PMID:27063511

Use of thulium-sensitized rare earth-doped low phonon energy crystalline hosts for IR sources.

PubMed

Ganem, Joseph; Bowman, Steven R

2013-11-01

Crystalline hosts with low phonon energies enable novel energy transfer processes when doped with rare earth ions. Two applications of energy transfer for rare earth ions in thulium-sensitized low phonon energy crystals that result in infrared luminescence are discussed. One application is an endothermic, phonon-assisted cross-relaxation process in thulium-doped yttrium chloride that converts lattice phonons to infrared emission, which raises the possibility of a fundamentally new method for achieving solid-state optical cooling. The other application is an optically pumped mid-IR phosphor using thulium-praseodymium-doped potassium lead chloride that converts 805-nm diode light to broadband emission from 4,000 to 5,500 nm. These two applications in chloride crystals are discussed in terms of critical radii calculated from Forster-Dexter energy transfer theory. It is found that the critical radii for electric dipole-dipole interactions in low phonon energy chloride crystals are comparable to those in conventional oxide and fluoride crystals. It is the reduction in multi-phonon relaxation rates in chloride crystals that enable these additional energy transfer processes and infrared luminescence.

Rejuvenation of the male scalp using 1,927 nm non-ablative fractional thulium fiber laser.

PubMed

Boen, Monica; Wilson, Monique J Vanaman; Goldman, Mitchel P; Wu, Douglas C

2017-07-01

The male scalp undergoes extensive photodamage due to a high prevalence of androgenic alopecia and exposure to ultraviolet radiation. This photodamage presents as solar lentigines, fine rhytides, and keratosis, and can prematurely age a patient. In this study, we demonstrate the safety and efficacy of the fractionated 1,927 nm thulium fiber laser using high density and high energy settings to achieve rejuvenation of the male scalp after a single treatment session. Four male patients with Fitzpatrick skin types II-III and extensive photodamage on the scalp underwent one treatment with the fractional non-ablative 1,927 nm thulium fiber laser. The patients had a 60-90% improvement in dyspigmentation, lentigines, and keratosis. No adverse events were observed and the patients tolerated the procedure well. This case series is the first report in the literature demonstrating the successful rejuvenation of the scalp using the 1,927 nm thulium fiber laser. Lasers Surg. Med. 49:475-479, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Use of thulium-sensitized rare earth-doped low phonon energy crystalline hosts for IR sources

NASA Astrophysics Data System (ADS)

Ganem, Joseph; Bowman, Steven R.

2013-11-01

Crystalline hosts with low phonon energies enable novel energy transfer processes when doped with rare earth ions. Two applications of energy transfer for rare earth ions in thulium-sensitized low phonon energy crystals that result in infrared luminescence are discussed. One application is an endothermic, phonon-assisted cross-relaxation process in thulium-doped yttrium chloride that converts lattice phonons to infrared emission, which raises the possibility of a fundamentally new method for achieving solid-state optical cooling. The other application is an optically pumped mid-IR phosphor using thulium-praseodymium-doped potassium lead chloride that converts 805-nm diode light to broadband emission from 4,000 to 5,500 nm. These two applications in chloride crystals are discussed in terms of critical radii calculated from Forster-Dexter energy transfer theory. It is found that the critical radii for electric dipole-dipole interactions in low phonon energy chloride crystals are comparable to those in conventional oxide and fluoride crystals. It is the reduction in multi-phonon relaxation rates in chloride crystals that enable these additional energy transfer processes and infrared luminescence.

Use of thulium-sensitized rare earth-doped low phonon energy crystalline hosts for IR sources

PubMed Central

2013-01-01

Crystalline hosts with low phonon energies enable novel energy transfer processes when doped with rare earth ions. Two applications of energy transfer for rare earth ions in thulium-sensitized low phonon energy crystals that result in infrared luminescence are discussed. One application is an endothermic, phonon-assisted cross-relaxation process in thulium-doped yttrium chloride that converts lattice phonons to infrared emission, which raises the possibility of a fundamentally new method for achieving solid-state optical cooling. The other application is an optically pumped mid-IR phosphor using thulium-praseodymium-doped potassium lead chloride that converts 805-nm diode light to broadband emission from 4,000 to 5,500 nm. These two applications in chloride crystals are discussed in terms of critical radii calculated from Forster-Dexter energy transfer theory. It is found that the critical radii for electric dipole-dipole interactions in low phonon energy chloride crystals are comparable to those in conventional oxide and fluoride crystals. It is the reduction in multi-phonon relaxation rates in chloride crystals that enable these additional energy transfer processes and infrared luminescence. PMID:24180684

Spectrally Tailored Pulsed Thulium Fiber Laser System for Broadband Lidar CO2 Sensing

NASA Technical Reports Server (NTRS)

Heaps, William S.; Georgieva, Elena M.; McComb, Timothy S.; Cheung, Eric C.; Hassell, Frank R.; Baldauf, Brian K.

2011-01-01

Thulium doped pulsed fiber lasers are capable of meeting the spectral, temporal, efficiency, size and weight demands of defense and civil applications for pulsed lasers in the eye-safe spectral regime due to inherent mechanical stability, compact "all-fiber" master oscillator power amplifier (MOPA) architectures, high beam quality and efficiency. Thulium fiber's longer operating wavelength allows use of larger fiber cores without compromising beam quality, increasing potential single aperture pulse energies. Applications of these lasers include eye-safe laser ranging, frequency conversion to longer or shorter wavelengths for IR countermeasures and sensing applications with otherwise tough to achieve wavelengths and detection of atmospheric species including CO2 and water vapor. Performance of a portable thulium fiber laser system developed for CO2 sensing via a broadband lidar technique with an etalon based sensor will be discussed. The fielded laser operates with approximately 280 J pulse energy in 90-150ns pulses over a tunable 110nm spectral range and has a uniquely tailored broadband spectral output allowing the sensing of multiple CO2 lines simultaneously, simplifying future potentially space based CO2 sensing instruments by reducing the number and complexity of lasers required to carry out high precision sensing missions. Power scaling and future "all fiber" system configurations for a number of ranging, sensing, countermeasures and other yet to be defined applications by use of flexible spectral and temporal performance master oscillators will be discussed. The compact, low mass, robust, efficient and readily power scalable nature of "all-fiber" thulium lasers makes them ideal candidates for use in future space based sensing applications.

Influence of Temperature on Nanosecond Pulse Amplification in Thulium Doped Fiber Lasers

NASA Astrophysics Data System (ADS)

Abdulfattah, Ali; Gausmann, Stefan; Sincore, Alex; Bradford, Joshua; Bodnar, Nathan; Cook, Justin; Shah, Lawrence; Richardson, Martin

2018-05-01

Thulium silica doped fiber (TDF) lasers are becoming important laser sources in both research and applications in industry. A key element of all high-power lasers is thermal management and its impact on laser performance. This is particularly important in TDF lasers, which utilize an unusual cross-relation pumping scheme, and are optically less efficient than other types of fiber lasers. The present work describes an experimental investigation of thermal management in a high power, high repetition-rate, pulsed Thulium (Tm) fiber laser. A tunable nanosecond TDF laser system across the 1838 nm – 1948 nm wavelength range, has been built to propagate 2μm signal seed pulses into a TDF amplifier, comprising a polarized large mode area (PLMA) thulium fiber (TDF) with a 793nm laser diode pump source. The PLMA TDF amplifier is thermally managed by a separately controlled cooling system with a temperature varied from 12°C to 36°C. The maximum output energy (∼400 μJ), of the system is achieved at 12°C at 1947 nm wavelength with ∼32 W of absorbed pump power at 20 kHz with a pulse duration of ∼ 74 ns.

Spatially resolved measurement of the core temperature in a high-power thulium fiber system

NASA Astrophysics Data System (ADS)

Walbaum, Till; Heinzig, Matthias; Beier, Franz; Liem, Andreas; Schreiber, Thomas; Eberhardt, Ramona; Tünnermann, Andreas

2016-03-01

We present measurements of the temperature increase inside the active fiber of a thulium fiber amplifier during high power operation. At a pump power of over 100 W at a wavelength of 793 nm, we measure the core temperature distribution along the first section of a large mode area (LMA) highly thulium doped active fiber by use of an optical backscatter reflectometer. A mode field adaptor is used to maintain single mode operation in the LMA fiber. An increase in temperature of over 100 K can be observed in spite of conductive cooling, located at the pumped fiber end and jeopardizing the fiber coating. The recoated splice can be clearly identified as the hottest fiber region. This allows us to estimate the maximum thermally acceptable pump power for this amplifier. We also observe that the temperature can be decreased by increasing the seed power, which is in agreement with theoretical predictions on the increase of cross relaxation efficiency by depletion of the upper laser level. This underlines the role of power scaling of the respective seed power of a thulium amplifier stage as a means of thermal management.

High-pressure structural, elastic, and thermodynamic properties of zircon-type HoPO 4 and TmPO 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gomis, O.; Lavina, B.; Rodríguez-Hernández, P.

2017-01-20

Zircon-type holmium phosphate (HoPO 4) and thulium phosphate (TmPO 4) have been studied by single-crystal x-ray diffraction and ab initio calculations. We report on the influence of pressure on the crystal structure, and on the elastic and thermodynamic properties. The equation of state for both compounds is accurately determined. We have also obtained information on the polyhedral compressibility which is used to explain the anisotropic axial compressibility and the bulk compressibility. Both compounds are ductile and more resistive to volume compression than to shear deformation at all pressures. Furthermore, the elastic anisotropy is enhanced upon compression. Finally, the calculations indicatemore » that the possible causes that make the zircon structure unstable are mechanical instabilities and the softening of a silent B 1u mode.« less

Carbon Nanotube Mode-Locked Thulium Fiber Laser With 200 nm Tuning Range

PubMed Central

Meng, Yafei; Li, Yao; Xu, Yongbing; Wang, Fengqiu

2017-01-01

We demonstrated a mode-locked thulium/holmium (Tm/Ho) fiber laser continuously tunable across 200 nm (from 1860 nm to 2060 nm), which to the best of our knowledge represents the widest tuning range ever achieved for a passively mode-locked fiber laser oscillator. The combined use of a broadband carbon nanotube (CNT) saturable absorber and a diffraction grating mirror ensures ultra-broad tuning range, superb stability and repeatability, and makes the demonstrated laser a highly practical source for spectroscopy, imaging and optical communications. The laser emits <5 ps pulses with an optical spectral bandwidth of ∼3 nm across the full tuning range. Our results indicate that carbon nanotubes can be an excellent saturable absorber for achieving gain-bandwidth-limited tunable operation for 2 μm thulium fiber lasers. PMID:28322327

Carbon Nanotube Mode-Locked Thulium Fiber Laser With 200 nm Tuning Range

NASA Astrophysics Data System (ADS)

Meng, Yafei; Li, Yao; Xu, Yongbing; Wang, Fengqiu

2017-03-01

We demonstrated a mode-locked thulium/holmium (Tm/Ho) fiber laser continuously tunable across 200 nm (from 1860 nm to 2060 nm), which to the best of our knowledge represents the widest tuning range ever achieved for a passively mode-locked fiber laser oscillator. The combined use of a broadband carbon nanotube (CNT) saturable absorber and a diffraction grating mirror ensures ultra-broad tuning range, superb stability and repeatability, and makes the demonstrated laser a highly practical source for spectroscopy, imaging and optical communications. The laser emits <5 ps pulses with an optical spectral bandwidth of ˜3 nm across the full tuning range. Our results indicate that carbon nanotubes can be an excellent saturable absorber for achieving gain-bandwidth-limited tunable operation for 2 μm thulium fiber lasers.

Two-micron (Thulium) Laser Prostatectomy: An Effective Method for BPH Treatment.

PubMed

Jiang, Qi; Xia, Shujie

2014-01-01

The two-micron (thulium) laser is the newest laser technique for treatment of bladder outlet obstruction resulting from benign prostatic hyperplasia (BPH). It takes less operative time than standard techniques, provides clear vision and lower blood loss as well as shorter catheterization times and hospitalization times. It has been identified to be a safe and efficient method for BPH treatment regardless of the prostate size.

Structural origin and laser performance of thulium-doped germanate glasses.

PubMed

Xu, Rongrong; Xu, Lin; Hu, Lili; Zhang, Junjie

2011-12-15

The structural origin and laser performance of thulium-doped germanate glasses have been studied. The investigation includes two main sections. The first part discusses the Raman spectroscopic and thermal stability of the host glass structure. The low value of the largest phonon energy (850 cm(-1)) reduces the probability of nonradiative relaxation. The large emission cross section of the Tm(3+) : (3)F(4) level (8.69 × 10(-21) cm(2)), the high quantum efficiency of the (3)F(4) level (71%), and the low nonradiative relaxation rate of the (3)F(4) → (3)H(6) transition (0.09 ms(-1)) illustrate good optical properties of the germanate glass. In the second part, the room-temperature laser action from the thulium-doped germanate glass is demonstrated when pumped by a 790 nm laser diode. The maximum output power of 346 mW and slope efficiency of 25.6% are achieved.

All-fiber passively Q-switched thulium-doped fiber laser by using a holmium-doped fiber as saturable absorber

NASA Astrophysics Data System (ADS)

Durán Sánchez, M.; Álvarez-Tamayo, R. I.; Posada-Ramírez, B.; Alaniz-Baylón, J.; Bravo-Huerta, E.; Santiago-Hernández, H.; Hernández-Arriaga, M. V.; Bello-Jiménez, Miguel; Ibarra-Escamilla, B.; Kuzin, E. A.

2018-02-01

We report a linear cavity all-fiber passive Q-switched thulium-doped fiber laser operating at the 2 μm wavelength range. The laser configuration is based on a thulium-doped fiber used as a gain medium and an unpumped segment of holmium-doped fiber which acts as a fiber saturable absorber. The cavity is formed by a fiber optical loop mirror and the flat end facet of the holmium-doped fiber. The fiber segments as saturable absorber is a 1-m long single mode doubleclad holmium-doped fiber. Q-switched pulses are obtained at the wavelength of 2024.5 nm with a pulse width of 1.1 μs. The pulse repetition rate increases as a linear function of the applied pump power. The maximum pulse repetition rate of 100 kHz was obtained with a pump power of 2.4 W.

1700 nm and 1800 nm band tunable thulium doped mode-locked fiber lasers.

PubMed

Emami, Siamak Dawazdah; Dashtabi, Mahdi Mozdoor; Lee, Hui Jing; Arabanian, Atoosa Sadat; Rashid, Hairul Azhar Abdul

2017-10-06

This paper presents short wavelength operation of tunable thulium-doped mode-locked lasers with sweep ranges of 1702 to 1764 nm and 1788 to 1831 nm. This operation is realized by a combination of the partial amplified spontaneous emission suppression method, the bidirectional pumping mechanism and the nonlinear polarization rotation (NPR) technique. Lasing at emission bands lower than the 1800 nm wavelength in thulium-doped fiber lasers is achieved using mode confinement loss in a specially designed photonic crystal fiber (PCF). The enlargement of the first outer ring air holes around the core region of the PCF attenuates emissions above the cut-off wavelength and dominates the active region. This amplified spontaneous emission (ASE) suppression using our presented PCF is applied to a mode-locked laser cavity and is demonstrated to be a simple and compact solution to widely tunable all-fiber lasers.

Q-switched oscillation in thulium-doped fiber lasers using preloaded dynamic microbending technique

NASA Astrophysics Data System (ADS)

Sakata, H.; Takahashi, N.; Ushiro, Y.

2018-01-01

We demonstrate Q-switched pulse generation in thulium-doped fiber lasers by introducing piezoelectric-driven microbend with preloaded stress. We employed a pair of corrugated chips each attached on piezoelectric actuators (PAs) to clamp the fiber in a ring laser resonator. The thulium-doped fiber is pumped by a laser diode emitting at 1.63 μm and generates the Q-switched laser pulses at around 1.9 μm by switching off the PAs. The laser pulse performance is improved by optimizing the preload and switch-off period for the PAs. The Q-switched pulses with a peak power of 2.8 W and a pulsewidth of 900 ns are observed for a launched pump power of 161 mW. We expect that the in-fiber Q-switching technique will provide efficient laser systems for environmental sensing and medical applications.

Treatment of burn scars in Fitzpatrick phototype III patients with a combination of pulsed dye laser and non-ablative fractional resurfacing 1550 nm erbium:glass/1927 nm thulium laser devices.

PubMed

Tao, Joy; Champlain, Amanda; Weddington, Charles; Moy, Lauren; Tung, Rebecca

2018-01-01

Burn scars cause cosmetic disfigurement and psychosocial distress. We present two Fitzpatrick phototype (FP) III patients with burn scars successfully treated with combination pulsed dye laser (PDL) and non-ablative fractional lasers (NAFL). A 30-year-old, FP III woman with a history of a second-degree burn injury to the bilateral arms and legs affecting 30% body surface area (BSA) presented for cosmetic treatment. The patient received three treatments with 595 nm PDL (7 mm, 8 J, 6 ms), six with the 1550 nm erbium:glass laser (30 mJ, 14% density, 4-8 passes) and five with the 1927 nm thulium laser (10 mJ, 30% density, 4-8 passes). Treated burn scars improved significantly in thickness, texture and colour. A 33-year-old, FP III man with a history of a second-degree burn injury of the left neck and arm affecting 7% BSA presented for cosmetic treatment. The patient received two treatments with 595 nm PDL (5 mm, 7.5 J, 6 ms), four with the 1550 nm erbium:glass laser (30 mJ, 14% density, 4-8 passes) and two with the 1927 nm thulium laser (10 mJ, 30% density, 4-8 passes). The burn scars became thinner, smoother and more normal in pigmentation and appearance. Our patients' burn scars were treated with a combination of PDL and NAFL (two wavelengths). The PDL targets scar hypervascularity, the 1550 nm erbium:glass stimulates collagen remodelling and the 1927 nm thulium targets epidermal processes, particularly hyperpigmentation. This combination addresses scar thickness, texture and colour with a low side effect profile and is particularly advantageous in patients at higher risk of post-procedure hyperpigmentation. Our cases suggest the combination of 595nm PDL plus NAFL 1550 nm erbium:glass/1927 nm thulium device is effective and well-tolerated for burn scar treatment in skin of colour.

Octave-spanning supercontinuum generation in in situ tapered As₂S₃ fiber pumped by a thulium-doped fiber laser.

PubMed

Rudy, Charles W; Marandi, Alireza; Vodopyanov, Konstantin L; Byer, Robert L

2013-08-01

We report a supercontinuum spanning well over an octave of measurable bandwidth from about 1 to 3.7 μm in a 2.1 mm long As₂S₃ fiber taper using the in situ tapering method. A sub-100-fs mode-locked thulium-doped fiber laser system with ~300 pJ of pulse energy was used as the pump source. Third-harmonic generation was observed and currently limits the pump pulse energy and achievable spectral bandwidth.

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

DTIC Science & Technology

2015-09-01

composite fiber laser of holmium-core and thulium-doped cladding . The composite fiber was optically pumped by an 803-nm fiber coupled diode source and was...4 odd and 5 even modes were exclusive to the core and first cladding . As the Tm laser modes are excluded from lasing in the second (undoped...of the Tm-doped clad /Ho-doped core fiber laser . In particular, calculations of the model overlap of the cladding modes with the core have been

X-ray diffraction study of elemental thulium to 86 GPa

NASA Astrophysics Data System (ADS)

Pravica, Michael; Romano, Edward; Quine, Zachary; Pravica, Walter

2006-03-01

We have studied the structures and equation of state of elemental thulium up to 86 GPa in a diamond anvil cell using angular-dispersive x-ray powder diffraction methods at the Advanced Photon Source. This is part of a study of phase transitions in the lanthanide-series metals using cyclohexane as a quasi-hydrostatic medium. We present evidence of a series of phase transitions that appear to follow the anticipated hcp ->Sm-type -> dhcp -> distorted fcc sequence of transitions and show the equation of state derived from the x-ray fit data.

Isolation and Structural Characterization of Two Very Large, and Largely Empty, Endohedral Fullerenes: Tm@C3v-C94 and Ca@C3v-C94

PubMed Central

Che, Yuliang; Yang, Hua; Wang, Zhimin; Jin, Hongxiao; Lu, Chunxin; Zuo, Tianming; Beavers, Christine M.

2009-01-01

The structures of two newly synthesized endohedral fullerenes - Tm@C3v-C94 and Ca@C3v-C94 - have been determined by single crystal X-ray diffraction on samples co-crystallized with NiII(octaethylporphyrin). Both compounds exhibit the same cage geometry and conform to the isolated pentagon rule (IPR). The metal ions within these rather large cages are localized near one end and along the C3 axis. While the calcium ion is situated over a C-C bond at a 6:6 ring junction, the thulium ion is positioned above a six-membered ring of the fullerene. PMID:19507844

Optical properties of bismuth and gallium substituted thulium iron garnet films

NASA Astrophysics Data System (ADS)

Gerhardt, R.; Sure, S.; Dötsch, H.; Linkewitz, T.; Tolksdorf, W.

1993-09-01

Bismuth and gallium substituted films of thulium iron garnet, grown by liquid phase epitaxy on [111] oriented substrates of gadolinium gallium garnet, are investigated for optical isolator applications. At a wavelength of λ = 1.3 μm the optical damping, the refractive index, the optical anisotropy, and the Faraday rotation are measured as function of the substitution level. It turns out that the growth induced optical anisotropy is very small, similar to the magnetic anisotropy. The observed difference between forward and backward propagation constants of TM modes is in excellent agreement with calculations.

Yb3+ sensitized Tm3+ upconversion in tellurite lead oxide glass.

PubMed

Mohanty, Deepak Kumar; Rai, Vineet Kumar; Dwivedi, Y

2012-04-01

Triply ionized thulium/thulium--ytterbium doped/codoped TeO2-Pb3O4 (TPO) glasses have been fabricated by classical quenching method. The upconversion emission spectra in the Tm3+/Tm3+-Yb3+ doped/codoped glasses upon excitation with a diode laser lasing at ∼980 nm has been studied. Effect of the addition of the Yb3+ on the upconversion emission intensity in the visible and near infrared regions of the Tm3+ doped in TPO glass has been studied and the processes involved explored. Copyright © 2011 Elsevier B.V. All rights reserved.

[Technique of thulium laser in managing bladder cuff in nephroureterectomy for upper urinary tract urothelium carcinoma].

PubMed

Pang, Kun; Sun, Xiao-Wen; Liu, Shi-Bo; Li, Wei-Guo; Shao, Yi; Zhuo, Jian; Wei, Hai-Bin; Xia, Shu-Jie

2012-11-13

To explore the application of thulium laser (2 µm laser) in managing bladder cuff in nephroureterectomy for upper urinary tract urothelium carcinoma (UUT-UC). The medical records of 56 patients undergoing nephroureterectomy at our hospital were reviewed retrospectively. The operative indicators, oncologic outcomes and clinicopathologic data were compared among the groups of open surgery (Group A), electric coagulation (Group B) and thulium laser technique (Group C). Furthermore a model of burst pressure measurement was built to measure the different burst pressures of sealing distal ureter. The follow-up results: when the indicators of operative duration, intraoperative blood loss volume, removal time of drainage tube, removal time of catheter and hospital stays were compared among three groups, Group A had no statistical differences with Group B/C in terms of removal time of drainage tube and removal time of catheter. But significant statistical differences existed in terms of operative duration, intraoperative blood loss volume and hospital stays ((232 ± 52) vs (148 ± 47) and (130 ± 49) min, (358 ± 81) vs (136 ± 74) and (145 ± 70) ml, (13 ± 3) vs (11 ± 4) and (10 ± 3) d, all P < 0.05). No statistical differences existed between Groups B and C in terms of all the above indicators. Burst pressure measurement results: no statistical differences existed between Group C and B ((116 ± 21) vs (139 ± 32) cm H2O, P > 0.05). For the surgical treatment of UUT-UC, thulium laser technique has no difference in operation indicators and oncologic outcomes compared to open surgery. Besides, it has the advantages of improved spatial beam quality and more precise tissue incision.

Thulium fiber laser lithotripsy using tapered fibers.

PubMed

Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

2010-01-01

The Thulium fiber laser has recently been tested as a potential alternative to the Holmium:YAG laser for lithotripsy. This study explores use of a short taper for expanding the Thulium fiber laser beam at the distal tip of a small-core fiber. Thulium fiber laser radiation with a wavelength of 1,908 nm, 10 Hz pulse rate, 70 mJ pulse energy, and 1-millisecond pulse duration was delivered through a 2-m-length fiber with 150-microm-core-input-end, 300-microm-core-output-end, and 5-mm-length taper, in contact with human uric acid (UA) and calcium oxalate monohydrate (COM) stones, ex vivo (n = 10 each). Stone mass loss, stone crater depths, fiber transmission losses, fiber burn-back, irrigation rates, and deflection through a flexible ureteroscope were measured for the tapered fiber and compared with conventional fibers. After delivery of 1,800 pulses through the tapered fiber, mass loss measured 12.7+/-2.6 mg for UA and 7.2+/-0.8 mg COM stones, comparable to conventional 100-microm-core fibers (12.6+/-2.5 mg for UA and 6.8+/-1.7 mg for COM stones). No transmission losses or burn-back occurred for the tapered fiber after 36,000 pulses, while a conventional 150-microm fiber experienced significant tip degradation after only 1,800 pulses. High irrigation rates were measured with the tapered fiber inserted through the working port of a flexible ureteroscope without hindering its deflection, mimicking that of a conventional 150 microm fiber. The short tapered distal fiber tip allows expansion of the laser beam, resulting in decreased fiber tip damage compared to conventional small-core fibers, without compromising fiber bending, stone vaporization efficiency, or irrigation rates.

Parameters for the RM1 Quantum Chemical Calculation of Complexes of the Trications of Thulium, Ytterbium and Lutetium

PubMed Central

Filho, Manoel A. M.; Dutra, José Diogo L.; Rocha, Gerd B.; Simas, Alfredo M.

2016-01-01

The RM1 quantum chemical model for the calculation of complexes of Tm(III), Yb(III) and Lu(III) is advanced. Subsequently, we tested the models by fully optimizing the geometries of 126 complexes. We then compared the optimized structures with known crystallographic ones from the Cambridge Structural Database. Results indicate that, for thulium complexes, the accuracy in terms of the distances between the lanthanide ion and its directly coordinated atoms is about 2%. Corresponding results for ytterbium and lutetium are both 3%, levels of accuracy useful for the design of lanthanide complexes, targeting their countless applications. PMID:27223475

Optimisation of thulium fibre laser parameters with generation of pulses by pump modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Obronov, I V; Larin, S V; Sypin, V E

2015-07-31

The formation of relaxation pulses of a thulium fibre laser (λ = 1.9 μm) by modulating the power of a pump erbium fibre laser (λ = 1.55 μm) is studied. A theoretical model is developed to find the dependences of pulse duration and peak power on different cavity parameters. The optimal cavity parameters for achieving the minimal pulse duration are determined. The results are confirmed by experimental development of a laser emitting pulses with a duration shorter than 10 ns, a peak power of 1.8 kW and a repetition rate of 50 kHz. (control of radiation parameters)

High pulse energy sub-nanosecond Tm-doped fiber laser

NASA Astrophysics Data System (ADS)

Cserteg, Andras; Guillemet, Sebastien; Hernandez, Yves; Giannone, Domenico

2012-02-01

We report a core pumped thulium-doped fiber amplifier that generates 1.4 μJ pulses at 1980 nm with a repetition rate of 3.6 MHz preserving the original spectral bandwidth of the oscillator. The amplifier chain is seeded by a passively modelocked fiber laser with 5 mW output power and the pulses are stretched to 800 picoseconds. The amplifier is core pumped by a single mode erbium fiber laser. The slope efficiency is 35%. To the best of our knowledge, this is the first demonstration of sub nanosecond pulses with energies higher than 1 μJ coming out of a thulium-doped fiber amplifier.

2-.mu.m fiber amplified spontaneous emission (ASE) source

NASA Technical Reports Server (NTRS)

Jiang, Shibin (Inventor); Wu, Jianfeng (Inventor); Geng, Jihong (Inventor)

2007-01-01

A 2-.mu.m fiber Amplified Spontaneous Emission (ASE) source provides a wide emission bandwidth and improved spectral stability/purity for a given output power. The fiber ASE source is formed from a heavy metal oxide multicomponent glass selected from germanate, tellurite and bismuth oxides and doped with high concentrations, 0.5-15 wt. %, thulium oxides (Tm.sub.2O.sub.3) or 0.1-5 wt% holmium oxides (Ho.sub.2O.sub.3) or mixtures thereof. The high concentration of thulium dopants provide highly efficient pump absorption and high quantum efficiency. Co-doping of Tm and Ho can broaden the ASE spectrum.

Two kinds of novel tunable Thulium-doped fiber laser

NASA Astrophysics Data System (ADS)

Ma, Xiaowei; Chen, Daru; Feng, Gaofeng; Yang, Junyong

2014-11-01

Two kinds of tunable Thulium-doped fiber laser (TDFL) respectively using a Sagnac loop mirror and a novel tunable multimode interference (MMI) fiber filter are experimentally demonstrated. The TDFL with the Sagnac loop mirror made by a 145.5-cm polarization-maintaining fiber (PMF) can operate with stable dual-wavelength lasing or tunable single-wavelength lasing around 1860nm. Both stable dual-wavelength and tunable single-wavelength lasing are achieved by adjusting a polarization controller in the Sagnac loop mirror. The TDFL with a novel tunable MMI fiber filter formed by splicing a segment of a special no-core fiber that is an all silica fiber without fiber core to single mode fibers can achieve tuning range from 1813.52 nm to 1858.70 nm. The no-core fiber with a large diameter of 200 μm is gradually vertically covered by refractive index matching liquid, which leads to a wavelength tuning of the transmission peak of the MMI fiber filter. The relationship between the refractive index of the refractive index matching liquid and the peak wavelength shift of the MMI fiber filter is also discussed. Using the MMI fiber filter, a Thulium-doped fiber laser with a tuning range of 45.18 nm is demonstrated.

Fiber laser at 2 μm for soft tissue surgery

NASA Astrophysics Data System (ADS)

Ghosh, Aditi; Pal, Debasis; Sen, Ranjan; Pal, Atasi

2014-11-01

Strong water absorption at 2 μm generated recent interest in lasers at this wavelength for soft tissue surgery. A fiber Bragg grating-based, all-fiber, continuous-wave, cladding pumped, thulium-doped fiber laser at 1.95 μm is configured. The thulium-doped active fiber with octagonal-shaped inner cladding is pumped at 808 nm (total power of 17 W) with six laser diodes through a combiner. The laser power of 3.3 W (after elimination of unabsorbed pump power through a passive fiber) with slope efficiency of 23% (against launched pump power) is achieved. The linear variation of laser power with pump offers scope of further power scaling.

152 fs nanotube-mode-locked thulium-doped all-fiber laser

PubMed Central

Wang, Jinzhang; Liang, Xiaoyan; Hu, Guohua; Zheng, Zhijian; Lin, Shenghua; Ouyang, Deqin; Wu, Xu; Yan, Peiguang; Ruan, Shuangchen; Sun, Zhipei; Hasan, Tawfique

2016-01-01

Ultrafast fiber lasers with broad bandwidth and short pulse duration have a variety of applications, such as ultrafast time-resolved spectroscopy and supercontinuum generation. We report a simple and compact all-fiber thulium-doped femtosecond laser mode-locked by carbon nanotubes. The oscillator operates in slightly normal cavity dispersion at 0.055 ps2, and delivers 152 fs pulses with 52.8 nm bandwidth and 0.19 nJ pulse energy. This is the shortest pulse duration and the widest spectral width demonstrated from Tm-doped all-fiber lasers based on 1 or 2 dimensional nanomaterials, underscoring their growing potential as versatile saturable absorber materials. PMID:27374764

Tunable thulium-doped fiber laser based on an abrupt-tapered in-fiber interferometer

NASA Astrophysics Data System (ADS)

Hernández-Arriaga, M. V.; Durán-Sánchez, M.; Ibarra-Escamilla, B.; Álvarez-Tamayo, R. I.; Santiago-Hernández, H.; Bello-Jiménez, M.; Kuzin, E. A.

2017-11-01

An experimental study of an all-fiber tunable thulium-doped fiber laser based on an abrupt-tapered in-fiber interferometer is presented. A microfiber filter with length of 6 mm and diameter of 20 μm is used to achieve single laser wavelength tuning in a range of 19.4 nm and dual-wavelength laser operation at 1761.8 and 1793.4 nm with a channel spacing of 31.6 nm. The abrupt-tapered structure allows multi-modal interference at the air-cladding interface. The proposed in-fiber interferometer exhibits characteristics of low cost and simple fabrication, making it suitable for practical applications in wavelength filtering and wavelength selection in all-fiber lasers.

Single-Frequency Narrow Linewidth 2 Micron Fiber Laser

NASA Technical Reports Server (NTRS)

Jiang, Shibin (Inventor); Spiegelberg, Christine (Inventor); Luo, Tao (Inventor)

2006-01-01

A compact single frequency, single-mode 2 .mu.m fiber laser with narrow linewidth, <100 kHz and preferably <100 kHz, is formed with a low phonon energy glass doped with triply ionized rare-earth thulium and/or holmium oxide and fiber gratings formed in sections of passive silica fiber and fused thereto. Formation of the gratings in passive silica fiber both facilitates splicing to other optical components and reduces noise thus improving linewidth. An increased doping concentration of 0.5 to 15 wt. % for thulium, holmium or mixtures thereof produces adequate gain, hence output power levels for fiber lengths less than 5 cm and preferably less than 3 cm to enable single-frequency operation.

Preparative scale separation of thulium from erbium for neutron capture cross section measurements - Part: Preparative scale

DOE PAGES

Birnbaum, Eva R.; Bene, Balazs J.; Taylor, Wayne Allen; ...

2016-06-04

Here, this paper discusses the development of a separation method for isolation of Tm-171 from a half-gram irradiated erbium target in support of stockpile stewardship and astrophysics research. The developed procedure is based on cation exchange separation using alpha-hydroxyisobutyric acid (α-HIBA) as chelating agent. It is able to achieve either a decontamination factor of 1.4(4) × 10 5 with 68.9(3) % recovery or 95.4(3) % recovery with a decontamination factor of 5.82(7) × 10 3 for a mock 500-mg target containing 17.9 mg thulium in a single pass-through at room temperature.

Comparing irradiation parameters on disinfecting enterrecoccus faecalis in root canal disinfection

NASA Astrophysics Data System (ADS)

Sarp, Ayşe. S.; Gülsoy, Murat

2016-02-01

Although conventional method carries all the debris, studies on persisting infections in root canals show bacteria and their toxins spread from the root canal and contaminate the apical region. Thus developes apical periodontitis or symptoms, and loss of tooth. Even if the treatment has adequate success, anatomy of root canal system can be very complexwith accessory canals. The disinfecting effect of laser radiation has only recently been used in dentistry. Laser irradiation has a bactericidal effect. Each wavelength has its own advantages and limitations according to their different absorption characteristics, depending on their 'absorption coefficient'. The sterilizing efficiency of two types of wavelengths, a new fiber laser 1940- nm Thulium fiber Laser and an 2940 nm Er:YAG Laser were compared in this study. Irradiation with a power of 0.50 W with 1940- nm Thulium fiber Laser disinfected 95,15% of bacteria, however irradiation with same laser power with Er:YAG Laser caused a reduction of 96,48 %. But there was no significant difference in the disinfection effect of two different laser groups ( p < 0.05, Mann- U-Whitney Test). In addition to this, Er :YAG Laser caused three times more reduction from its own positive control group where 1940- nm Thulium fiber Laser caused 2,5 times effective disinfection.

Different lasers in the treatment of benign prostatic hyperplasia: a network meta-analysis

PubMed Central

Zhang, Xingming; Shen, Pengfei; He, Qiying; Yin, Xiaoxue; Chen, Zhibin; Gui, Haojun; Shu, Kunpeng; Tang, Qidun; Yang, Yaojing; Pan, Xiuyi; Wang, Jia; Chen, Ni; Zeng, Hao

2016-01-01

All available surgical treatments for benign prostatic hyperplasia (BPH) have their individual advantages or disadvantages. However, the lack of head-to-head studies comparing different surgeries makes it unavailable to conduct direct analysis. To compare the efficacy and safety among different lasers and transurethral resection of prostate (TURP) for BPH, randomized controlled trials were searched in MEDLINE, EMBASE, Cochrane library, WHO International Clinical Trial Registration Platform, and Clinical Trial.gov by 2015.5; and the effectiveness-, perioperation- and complication-related outcomes were assessed by network meta-analysis. 36 studies involving 3831 patients were included. Holmium laser through resection and enucleation had the best efficacy in maximum flow rate. Thulium laser through vapo-resection was superior in improving international prostate symptom score and holmium laser through enucleation was the best for post-voiding residual volume improvement. Diode laser through vaporization was the rapidest in removing postoperative indwelling catheter, while TURP was the longest. TURP required the longest hospitalization and thulium laser through vapo-resection was relatively shorter. Holmium and thulium lasers seem to be relatively better in surgical efficacy and safety, so that these two lasers might be preferred in selection of optimal laser surgery. Actually, more large-scale and high quality head-to-head RCTs are suggested to validate the conclusions. PMID:27009501

Thulium vapoenucleation of the prostate versus holmium laser enucleation of the prostate for the treatment of large volume prostates: preliminary 6-month safety and efficacy results of a prospective randomized trial.

PubMed

Becker, B; Herrmann, T R W; Gross, A J; Netsch, C

2018-05-05

We compared the perioperative and postoperative characteristics of thulium vapoenucleation and holmium laser enucleation of the prostate for the treatment of large volume benign prostatic hyperplasia. A total of 94 patients with benign prostatic hyperplasia and a median prostate size of 80 (IQR 46.75-100) cc were either randomized to thulium vapoenucleation or holmium laser enucleation of the prostate. Patients were assessed preoperatively, 1 and 6 months postoperatively. The median operative time was 60 (IQR 41-79) min without significant differences between the groups. There were no significant differences between the groups regarding catheter time [2 (IQR 2-2) days] and postoperative stay [2 (IQR 2-3) days]. Clavien 1 (13.8%), 2 (3.2%), 3a (2.1%), and Clavien 3b (4.3%) complications occurred without significant differences between the groups. At 6-month follow-up, median maximum flow rate (10.7 vs. 25.9 ml/s), post-void residual urine (100 vs. 6.5 ml), I-PSS (20 vs. 5), quality of life (4 vs. 1), PSA (4.14 vs. 0.71 µg/l), and prostate volume (80 vs. 16 ml) had improved significantly (p < 0.001) compared to baseline without significant differences between the groups. Median PSA decrease was 79.7% (58.8-90.6%) and prostate volume reduction was 74.5% (68.57-87.63%) without differences between the groups. The reoperation rate was zero at 6-month follow-up. Thulium vapoenucleation and holmium laser enucleation of the prostate are safe and effective procedures for the treatment of large volume benign prostatic hyperplasia. Both procedures give satisfactory micturition improvement with low morbidity and sufficient prostate volume reduction at 6-month follow-up.

A comparative study of thulium laser resection of the prostate and bipolar transurethral plasmakinetic prostatectomy for treating benign prostatic hyperplasia.

PubMed

Peng, Bo; Wang, Guang-chun; Zheng, Jun-hua; Xia, Sheng-qiang; Geng, Jiang; Che, Jian-ping; Yan, Yang; Huang, Jian-hua; Xu, Yun-fei; Yang, Bin

2013-04-01

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: Thulium laser is a new generation of surgical laser. It is a minimally invasive technology with several advantages, including rapid vaporization and minimal tissue damage and bleeding. However, details regarding the safety and efficacy of thulium laser in treating BPH remains unknown. We performed a comparative study in 100 patients with BPH of the safety and efficacy of thulium laser resection of the prostate (TMLRP, n = 50) and bipolar transurethral plasmakinetic prostatectomy (TUPKP, n = 50). We found that the efficacy and indications were the same in TMLRP and TUPKP. In TUPKP, the morbidity of urethrostenosis was low, and was nearly bloodless in surgery and had higher safety. Nevertheless, TUPKP is more suitable for patients with larger prostate volume. To compare the safety and short-term efficacy of thulium laser resection of the prostate (TMLRP) and bipolar transurethral plasmakinetic prostatectomy (TUPKP) for the treatment of patients with benign prostatic hyperplasia (BPH). A total of 100 patients diagnosed with BPH were randomly divided into two groups, treated with either TMLRP (50, group 1) or TUPKP (50, group 2). There was no significant difference in preoperative variables such as age, prostate volume, prostate-specific antigen (PSA) level, International Prostate Symptom Score (IPSS), maximum urinary flow rate (Qmax ) and postvoid residual urine volume (PVR) between the two groups. The perioperative parameters and therapeutic effects were recorded and compared between the two groups. There were significant differences in the following parameters between the two groups (TMLRP vs TUPKP [mean ± SD]): operation duration, 61.2 ± 24.2 vs 30.14 ± 15.9 min; catheterization time, 1.8 ± 0.4 vs 3.2 ± 0.6 d; postoperative hospital stay, 3.3 ± 0.8 vs 4.1 ± 1.3 d. The volume of blood loss and postoperative bladder irrigation were significantly lower in TMLRP group than in the TUPKP group. At 1 month after the operation, there were four cases of urethral stricture in the TUPKP group. At 3 months after the operation, IPSS, quality of life (QoL), Qmax and PVR were significantly improved, with no significant difference between the two groups. TMLRP is superior to TUPKP in terms of safety, blood loss, recovery time and complication rate, and is as efficacious as TUPKP for treating BPH. Operation duration was significantly longer in the TMLRP group than in the TUPKP group. © 2012 BJU International.

Thulium-170 heat source

DOEpatents

Walter, Carl E.; Van Konynenburg, Richard; VanSant, James H.

1992-01-01

An isotopic heat source is formed using stacks of thin individual layers of a refractory isotopic fuel, preferably thulium oxide, alternating with layers of a low atomic weight diluent, preferably graphite. The graphite serves several functions: to act as a moderator during neutron irradiation, to minimize bremsstrahlung radiation, and to facilitate heat transfer. The fuel stacks are inserted into a heat block, which is encased in a sealed, insulated and shielded structural container. Heat pipes are inserted in the heat block and contain a working fluid. The heat pipe working fluid transfers heat from the heat block to a heat exchanger for power conversion. Single phase gas pressure controls the flow of the working fluid for maximum heat exchange and to provide passive cooling.

Rare Earth Doped High Temperature Ceramic Selective Emitters

NASA Technical Reports Server (NTRS)

Chubb, Donald L.; Pal, AnnaMarie; Patton, Martin O.; Jenkins, Phillip P.

1999-01-01

As a result of their electron structure, rare earth ions in crystals at high temperature emit radiation in several narrow bands rather than in a continuous blackbody manner. This study develops a spectral emittance model for films of rare earth containing materials. Although there are several possible rare earth doped high temperature materials, this study was confined to rare earth aluminum garnets. Good agreement between experimental and theoretical spectral emittances was found for erbium, thulium and erbium-holmium aluminum garnets. Spectral emittances of these films are sensitive to temperature differences across the film. Emitter efficiency is also a sensitive function of temperature. For thulium aluminum garnet the efficiency is 0.38 at 1700 K but only 0.19 at 1262 K.

Switchable and spacing-tunable dual-wavelength thulium-doped silica fiber laser based on a nonlinear amplifier loop mirror.

PubMed

Liu, Shuo; Yan, Fengping; Feng, Ting; Wu, Beilei; Dong, Ze; Chang, Gee-Kung

2014-08-20

A kind of switchable and spacing-tunable dual-wavelength thulium-doped silica fiber laser based on a nonlinear amplifier loop mirror is presented and experimentally demonstrated. By adjusting the polarization controllers (PCs), stable dual-wavelength operation is obtained at the 2 μm band. The optical signal-to-noise ratio (OSNR) is better than 56 dB. The wavelength tuning is performed by applying static strain into the fiber Bragg grating. A tuning range from 0 to 5.14 nm is achieved for the dual-wavelength spacing. By adjusting the PCs properly, the fiber laser can also operate in single-wavelength state with the OSNR for each wavelength more than 50 dB.

A passively mode locked thulium doped fiber laser using bismuth telluride deposited multimode interference

NASA Astrophysics Data System (ADS)

Jung, M.; Lee, J.; Song, W.; Lee, Y. L.; Lee, J. H.; Shin, W.

2016-05-01

We proposed a multimode interference (MMI) fiber based saturable absorber using bismuth telluride at  ∼2 μm region. Our MMI based saturable absorber was fabricated by fusion splicing with single mode fiber and null core fiber. The MMI functioned as both wavelength fixed filter and saturable absorber. The 3 dB bandwidth and insertion loss of MMI were 42 nm and 3.4 dB at wavelength of 1958 nm, respectively. We have also reported a passively mode locked thulium doped fiber laser operating at a wavelength of 1958 nm using a multimode interference. A temporal bandwidth of  ∼46 ps was experimentally obtained at a repetition rate of 8.58 MHz.

Analysis of soft x-ray emission spectra of laser-produced dysprosium, erbium and thulium plasmas

NASA Astrophysics Data System (ADS)

Sheil, John; Dunne, Padraig; Higashiguchi, Takeshi; Kos, Domagoj; Long, Elaine; Miyazaki, Takanori; O'Reilly, Fergal; O'Sullivan, Gerard; Sheridan, Paul; Suzuki, Chihiro; Sokell, Emma; White, Elgiva; Kilbane, Deirdre

2017-03-01

Soft x-ray emission spectra of dysprosium, erbium and thulium ions created in laser-produced plasmas were recorded with a flat-field grazing-incidence spectrometer in the 2.5-8 nm spectral range. The ions were produced using an Nd:YAG laser of 7 ns pulse duration and the spectra were recorded at various power densities. The experimental spectra were interpreted with the aid of the Cowan suite of atomic structure codes and the flexible atomic code. At wavelengths above 5.5 nm the spectra are dominated by overlapping n = 4 - n = 4 unresolved transition arrays from adjacent ion stages. Below 6 nm, n = 4 - n = 5 transitions also give rise to a series of interesting overlapping spectral features.

Narrow linewidth power scaling and phase stabilization of 2-μm thulium fiber lasers

NASA Astrophysics Data System (ADS)

Goodno, Gregory D.; Book, Lewis D.; Rothenberg, Joshua E.; Weber, Mark E.; Benjamin Weiss, S.

2011-11-01

Thulium-doped fiber lasers (TFLs) emitting retina-safe 2-μm wavelengths offer substantial power-scaling advantages over ytterbium-doped fiber lasers for narrow linewidth, single-mode operation. This article reviews the design and performance of a pump-limited, 600 W, single-mode, single-frequency TFL amplifier chain that balances thermal limitations against those arising from stimulated Brillouin scattering (SBS). A simple analysis of thermal and SBS limits is anchored with measurements on kilowatt class Tm and Yb fiber lasers to highlight the scaling advantage of Tm for narrow linewidth operation. We also report recent results on active phase-locking of a TFL amplifier to an optical reference as a precursor to further parallel scaling via coherent beam combining.

Magneto-optical trap for thulium atoms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sukachev, D.; Sokolov, A.; Chebakov, K.

2010-07-15

Thulium atoms are trapped in a magneto-optical trap using a strong transition at 410 nm with a small branching ratio. We trap up to 7x10{sup 4} atoms at a temperature of 0.8(2) mK after deceleration in a 40-cm-long Zeeman slower. Optical leaks from the cooling cycle influence the lifetime of atoms in the magneto-optical trap which varies between 0.3 and 1.5 s in our experiments. The lower limit for the leaking rate from the upper cooling level is measured to be 22(6) s{sup -1}. The repumping laser transferring the atomic population out of the F=3 hyperfine ground-state sublevel gives amore » 30% increase for the lifetime and the number of atoms in the trap.« less

Telecom to mid-infrared spanning supercontinuum generation in hydrogenated amorphous silicon waveguides using a Thulium doped fiber laser pump source.

PubMed

Dave, Utsav D; Uvin, Sarah; Kuyken, Bart; Selvaraja, Shankar; Leo, Francois; Roelkens, Gunther

2013-12-30

A 1,000 nm wide supercontinuum, spanning from 1470 nm in the telecom band to 2470 nm in the mid-infrared is demonstrated in a 800 nm x 220 nm 1 cm long hydrogenated amorphous silicon strip waveguide. The pump source was a picosecond Thulium doped fiber laser centered at 1950 nm. The real part of the nonlinear parameter of this waveguide at 1950 nm is measured to be 100 ± 10 W -1m-1, while the imaginary part of the nonlinear parameter is measured to be 1.2 ± 0.2 W-1m-1. The supercontinuum is stable over a period of at least several hours, as the hydrogenated amorphous silicon waveguides do not degrade when exposed to the high power picosecond pulse train.

Infrastructure for thulium-170 isotope power systems for autonomous underwater vehicle fleets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walter, C.E.

1991-07-01

The radioisotope thulium-170 is a safe and environmentally benign heat source for providing the high endurance and energy densities needed by advanced power systems for autonomous underwater vehicles (AUV). Thulium Isotope Power (TIP) systems have an endurance of {approximately}3000 h, and gravimetric and volumetric energy densities of 3 {times} 10{sup 4} Wh/kg and 3 {times} 10{sup 8} Wh/m{sup 3}, respectively. These energy densities are more than 200 times higher than those currently provided by Ag-Zn battery technology. In order to capitalize on these performance levels with about one hundred AUVs in continuous use, it will be necessary to establish anmore » infrastructure for isotope production and heat-source refurbishment. The infrastructure cost is not trivial, and studies are needed to determine its optimum configuration. The major component of the projected infrastructure is the nuclear reactor used to produce Tm- 170 by neutron absorption in Tm-169. The reactor design should ideally be optimized for TM-170 production. Using the byproduct waste'' heat beneficially would help defray the cost of isotope production. However, generating electric power with the reactor would compromise both the cost of electricity and the isotope production capacity. A coastal location for the reactor would be most convenient from end-use considerations, and the waste'' heat could be used to desalinate seawater in water-thirsty states. 13 refs., 6 figs., 2 tabs.« less

Spectroscopic properties of Tm3+/Al3+ co-doped sol-gel silica glass

NASA Astrophysics Data System (ADS)

Wang, Xue; Lou, Fengguang; Wang, Shikai; Yu, Chunlei; Chen, Danping; Hu, Lili

2015-04-01

Tm3+/Al3+ co-doped silica glass was prepared by sol-gel method combined with high temperature sintering. Glasses with compositions of xTm2O3-15xAl2O3-(100 - 16x) SiO2 (in mol%, x = 0.1, 0.3, 0.5, 0.8 and 1.0) were prepared. The high thulium doped silica glass was realized. Their spectroscopic parameters were calculated and analyzed by Judd-Ofelt theory. Large absorption cross section (4.65 × 10-21 cm2 at 1668 nm) and stimulated emission cross section (6.00 × 10-21 cm2 at 1812 nm), as well as low hydroxyl content (0.180 cm-1), long fluorescence lifetime (834 μs at 1800 nm), large σem × τrad (30.05 × 10-21 cm2 ms) and large relative intensity ratio of the 1.8 μm (3F4 → 3H6) to 1.46 (3H4 → 3F4) emissions (90.33) are achieved in this Tm3+/Al3+ co-doped silica glasses. According to emission characteristics, the optimum thulium doping concentration is around 0.8 mol%. The cross relaxation (CR) between ground and excited states of Tm3+ ions was used to explain the optimum thulium doping concentration. These results suggest that the sol-gel method is an effective way to prepare Tm3+ doped silica glass with high Tm3+ doping and prospective spectroscopic properties.

Transoral robotic surgery using the thulium:YAG laser: a prospective study.

PubMed

Van Abel, Kathryn M; Moore, Eric J; Carlson, Matthew L; Davidson, Jennifer A; Garcia, Joaquin J; Olsen, Steven M; Olsen, Kerry D

2012-02-01

To compare thulium:YAG laser-assisted transoral robotic surgery (TY:TORS) and conventional electrocautery-equipped TORS (EC:TORS) in patients undergoing transoral resection of upper aerodigestive tract malignant neoplasms. Prospective matched cohort study. Tertiary academic referral center. Fifteen patients undergoing TY:TORS were matched on the basis of tumor site, clinical T stage, sex, and age with 30 control subjects undergoing EC:TORS. The primary outcome was a comparison between the feasibility of TY:TORS compared with EC:TORS. The secondary outcome was a comparison between the safety and functional outcome of TY:TORS compared with EC:TORS in patients undergoing resection of upper aerodigestive tract malignant neoplasms. All the tumors underwent complete excision with negative margins. Estimated blood loss was minimal (<150 mL) for 87% of TY:TORS patients (13 of 15) and 63% of EC:TORS controls (19 or 30). Intraoperative pharyngotomy was reported in 8% of TY:TORS patients (1 of 13) and 42% of EC:TORS controls (11 of 30) (P = .03). Postoperative pain was greater in EC:TORS compared with TY:TORS (P = .02). No statistically significant differences were noted in hemostasis, postoperative bleeding rates, or other complications. Compared with EC:TORS, TY:TORS seems feasible and safe. In addition, TY:TORS resulted in fewer intraoperative pharyngotomies and less postoperative pain than did EC:TORS, which may be because of decreased collateral thermal damage, improved visualization, and finer cutting using the thulium laser.

Continuous-wave and quasi-continuous wave thulium-doped all-fiber laser: implementation on kidney stone fragmentations.

PubMed

Pal, Debasis; Ghosh, Aditi; Sen, Ranjan; Pal, Atasi

2016-08-10

A continuous-wave (CW) as well as quasi-continuous wave (QCW) thulium-doped all-fiber laser at 1.94 μm has been designed for targeting applications in urology. The thulium-doped active fiber with an octagonal-shaped inner cladding is pumped at 793 nm to achieve stable CW laser power of 10 W with 32% lasing efficiency (against launched pump power). The linear variation of laser power with pump offers a scope of further power scaling. A QCW operation with variation of duty cycle from 0.5% to 90%, repetition rate from 0.1 Hz to 1 kHz, and pulse width from 40 μs to 2 s has been presented. Laser power of 9.5 W in CW mode of operation and average power of 5.2 W with energy range of 10.4-104 mJ in QCW mode of operation has been employed to fragment calcium oxalate monohydrate kidney stones (size of 1.5-4 cm) having different colors and composition. Dependence of ablation threshold, ablation rate, and average fragmented particle size on the average power and energy has been studied. One minute of laser exposure results in fragmentation of a stone surface with ablation rate of 8  mg/min having minimum particle size of 6.54 μm with an average size of 20-100 μm ensuring the natural removal of fragmented parts through the urethra.

Dual-wavelength nano-engineered Thulium-doped fiber laser via bending of singlemode-multimode-singlemode fiber structure

NASA Astrophysics Data System (ADS)

Zulkifli, A. Z.; Latiff, A. A.; Paul, M. C.; Yasin, M.; Ahmad, H.; Harun, S. W.

2016-12-01

In this paper, a dual-wavelength fiber laser (DWFL) using nano-engineered Thulium-doped fiber as a gain medium with a bent singlemode-multimode-singlemode fiber structure (SMS) is demonstrated. The SMS structure is packaged systematically using Cr-39 polymer plates to provide linear bending via applied load. Experimental results have proved that the bent SMS is capable to provide highly effective wavelength filter and wavelengths stabilizer by balancing the net cavity gain between the two wavelengths. The DWFL provides very narrow spacing of 0.9 nm, narrow 3 dB spectral linewidth of ∼0.07 nm and SNR of ∼42 dB. Based on stability test, very small mode hopping is observed at the two wavelengths having deviations of ±0 nm and ±0.04 nm respectively. In conjunction, the DWFL provides very stable relative wavelength spacing with a deviation of ±0.04 nm.

Switchable multiwavelength thulium-doped fiber ring lasers

NASA Astrophysics Data System (ADS)

Zhao, Shui; Lu, Ping; Liu, Deming; Zhang, Jiangshan

2013-08-01

Two kinds of thulium-doped fiber ring lasers based on a spatial mode beating filter and comb filtering effect are presented and experimentally demonstrated, which all show multiwavelength laser spectrum around 2 μm. In the implementation of the first type of experiment configuration by the use of a piece of multimode fiber (MMF) as a spatial mode beating filter, dual-,triple-, and quadruple-wavelengths appeared whose extinction noise ratio is 25 dB by adjusting the angle of polarization controller. Different wavelength spaces are obtained by inserting different lengths of MMF. The second type is achieved by inserting a Sagnac loop mirror, which was constructed by a 3-dB coupler and a piece of polarization maintaining fiber. Seven stable wavelengths with channel spacing of 0.65 nm and an extinction ratio of 35 dB was achieved. These systems are simple and easy to construct, which can be useful for 2 μm wavelength-division-multiplexed applications.

Ultra-short wavelength operation in Thulium-doped silica fiber laser with bidirectional pumping

NASA Astrophysics Data System (ADS)

Xiao, Xusheng; Guo, Haitao; Yan, Zhijun; Wang, Hushan; Xu, Yantao; Lu, Min; Wang, Yishan; Peng, Bo

2017-02-01

An ultra-short wavelength operation of Tm-doped all fiber laser based on fiber Bragg gratings (FBGs) was developed. A bi-directional pump configuration for the ultra-short wavelength operation was designed and investigated for the first time. the laser yielded 3.15W of continuous-wave output at 1706.75nm with a narrow-linewidth of 50pm and a maximum slope efficiency of 42.1%. The dependencies of the slope efficiencies and pump threshold of the laser versus the length of active fiber and reflectivity of the output mirror (FBG) were investigated in detail. An experimental comparative study between two Thulium-doped fiber lasers (TDFLs) with two different pumping configuration(forward unidirectional pumping and bidirectional pumping) was presented. It is indisputable that the development of 1.7μm silicate fiber lasers with Watt-level output power open up a number of heart-stirring and tempting application windows.

Wavelength-tunable thulium-doped fiber laser by employing a self-made Fabry-Perot filter

NASA Astrophysics Data System (ADS)

Wang, Y. P.; Ju, Y. L.; Wu, C. T.; Liu, W.; Yang, C.

2017-06-01

In this demonstration, we proposed a novel wavelength-tunable thulium-doped fiber laser (TDFL) with a self-made Fabry-Perot (F-P) filter. When the F-P filter was not inserted, the maximum output power of 11.1 W was achieved when the pump power was 70.2 W. The corresponding optical-to-optical conversion efficiency was 15.8% and the slope efficiency was 22.1%. When the F-P filter was inserted, the output wavelength could be tuned from 1952.9 to 1934.9 nm with the change of cavity length of F-P filter which was fixed on a piezoelectric ceramic transducer (PZT) controlled by the voltage applied to it. The full width at half maximum (FWHM) was no more than 0.19 nm. Furthermore, the wavelength fluctuations of the tunable fiber laser were kept within  ±0.2 nm.

Actively Q-switched, thulium-holmium-codoped fiber laser incorporating a silicon-based, variable-optical-attenuator-based Q switch.

PubMed

Jung, Minwan; Han Lee, Ju

2013-04-20

An actively Q-switched thulium-holmium-codoped fiber laser incorporating an Si-based variable optical attenuator (VOA) is experimentally demonstrated. It has been shown that an Si-based VOA with a response time of hundreds of nanoseconds can be used as a cost-effective 2 μm Q switch due to its extremely wide operating bandwidth from 1.5 to 2 μm, and low electrical power consumption. In our study, the laser's slope efficiency was measured to be ~17% at an operating wavelength of 1.89 μm. The repetition rate tuning range was from 20 to 80 kHz, which was limited by the optical damage threshold and the response time. The minimum temporal pulsewidth was measured to be ~184 ns at a modulation frequency of 20 kHz, and the corresponding maximum peak power was ~10 W.

In vivo study of partial liver resection on pigs using a 1.9 μm thulium fiber laser

NASA Astrophysics Data System (ADS)

Theisen-Kunde, D.; Wolken, H.; Danicke, V.; Brinkmann, R.; Bruch, H.; Kleemann, M.

2011-07-01

Dissection of liver tissue can be performed by different techniques (ultrasound, mono and bipolar dissection, water jet dissection and by stapler). In this animal study the potential of a Thulium fiber laser system was investigated for open parenchyma dissection. Based on a cw Thulium fiber laser (IPG laser GmbH, Burbach, Germany), emitting a wavelength at 1.9 μm and a maximal power at 50 W, a surgical dissection device was developed at the Medical Laser Centre Luebeck. Cw laser radiation (40 Watt) was transmitted via a 365 μm fiber with a polished distal fiber tip. Procedure was performed in contact mode; irradiance at the distal fiber tip was 38.2 kW/cm2. After general anesthesia and a median laparotomy an atypical laser resection of the liver was performed in 3 pigs. Healing process was controlled after 2-3 weeks by histological analysis (H&E staining). The final evaluation data included total resection time, blood loss, bile leakage and mass of dissected tissue. All animals treated in this study were cared for in accordance to the European convention on animal care. In general the dissection with the 1.9 μm laser radiation was easily performed. Hemostasis was highly sufficient so blood loss and bile leakage was negligible. Total resection time including hemostasis of the remaining tissue was 26 +/- 12 min. Weight of resected tissue was 17 +/- 8 g. During survival period no complications (bleeding or inflammation) occurred. After 2 weeks histology showed ongoing scar formation about 1 - 2 mm in depth of the dissected area.

Proximal fiber tip damage during Holmium:YAG and thulium fiber laser ablation of kidney stones

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

2016-02-01

The Thulium fiber laser (TFL) is being studied as an alternative to Holmium:YAG laser for lithotripsy. TFL beam originates within an 18-μm-core thulium doped silica fiber, and its near single mode, Gaussian beam profile enables transmission of higher laser power through smaller fibers than possible during Holmium laser lithotripsy. This study examines whether TFL beam profile also reduces proximal fiber tip damage compared to Holmium laser multimodal beam. TFL beam at wavelength of 1908 nm was coupled into 105-μm-core silica fibers, with 35-mJ energy, 500-μs pulse duration, and pulse rates of 50-500 Hz. For each pulse rate, 500,000 pulses were delivered. Magnified images of proximal fiber surfaces were taken before and after each trial. For comparison, 20 single-use, 270-μm-core fibers were collected after clinical Holmium laser lithotripsy procedures using standard settings (600 mJ, 350 μs, 6 Hz). Total laser energy, number of laser pulses, and laser irradiation time were recorded, and fibers were rated for damage. For TFL studies, output power was stable, and no proximal fiber damage was observed after delivery of 500,000 pulses at settings up to 35 mJ, 500 Hz, and 17.5 W average power. In contrast, confocal microscopy images of fiber tips after Holmium lithotripsy showed proximal fiber tip degradation in all 20 fibers. The proximal fiber tip of a 105-μm-core fiber transmitted 17.5 W of TFL power without degradation, compared to degradation of 270-μm-core fibers after transmission of 3.6 W of Holmium laser power. The smaller and more uniform TFL beam profile may improve fiber lifetime, and potentially reduce costs for the surgical disposables as well.

Thulium fiber laser ablation of kidney stones using a 50-μm-core silica optical fiber

NASA Astrophysics Data System (ADS)

Blackmon, Richard L.; Hutchens, Thomas C.; Hardy, Luke A.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

2015-01-01

Our laboratory is currently studying the experimental thulium fiber laser (TFL) as a potential alternative laser lithotripter to the gold standard, clinical Holmium:YAG laser. We have previously demonstrated the efficient coupling of TFL energy into fibers as small as 100-μm-core-diameter without damage to the proximal end. Although smaller fibers have a greater tendency to degrade at the distal tip during lithotripsy, fiber diameters (≤200 μm) have been shown to increase the saline irrigation rates through the working channel of a flexible ureteroscope, to maximize the ureteroscope deflection, and to reduce the stone retropulsion during laser lithotripsy. In this study, a 50-μm-core-diameter, 85-μm-outer-diameter, low-OH silica fiber is characterized for TFL ablation of human calcium oxalate monohydrate urinary stones, ex vivo. The 50-μm-core fiber consumes approximately 30 times less cross-sectional area inside the single working channel of a ureteroscope than the standard 270-μm-core fiber currently used in the clinic. The ureteroscope working channel flow rate, including the 50-μm fiber, decreased by only 10% with no impairment of ureteroscope deflection. The fiber delivered up to 15.4±5.9 W under extreme bending (5-mm-radius) conditions. The stone ablation rate measured 70±22 μg/s for 35-mJ-pulse-energy, 500-μs-pulse-duration, and 50-Hz-pulse-rate. Stone retropulsion and fiber burnback averaged 201±336 and 3000±2600 μm, respectively, after 2 min. With further development, thulium fiber laser lithotripsy using ultra-small, 50-μm-core fibers may introduce new integration and miniaturization possibilities and potentially provide an alternative to conventional Holmium:YAG laser lithotripsy using larger fibers.

First collaborative experience with thulium laser ablation of localized upper urinary tract urothelial tumors using retrograde intra-renal surgery.

PubMed

Defidio, Lorenzo; De Dominicis, Mauro; Di Gianfrancesco, Luca; Fuchs, Gerhard; Patel, Anup

2011-09-01

Thulium laser ablation (TLA) outcomes with blinded performance evaluation after retrograde intra-renal surgical (RIRS) treatment of upper urinary tract transitional cell carcinomas (UUT-TCC). A UUT-TCC patient cohort undergoing RIRS-TLA by an international endoscopic surgical collaboration in a European center (April 2005-July 2009), underwent outcomes evaluation. All 4 surgeons were blinded and independently scored both TLA and Holmium:YAG laser ablation performance aspects annually using a Likert scoring system (0-10). All patients (n = 59, median age 66 years, 9 with solitary kidney) had complete UUT inspection. Presenting lesion(s) were intra-renal (n = 30, 51%), ureteral (n = 13, 22%), and combined (n = 16, 27%). Single-stage TLA sufficed in 81.4% (tumors < 1.5 cm). Significant recurrence free survival differences occurred according to primary tumor size >/< 1.5 cm and multi-focality, but location made no difference. Median Likert scores were i) fiber-tip stability --5.5/8.75, p = 0.016; ii) reduced bleeding--5/8.5, p = 0.004; iii)fiber-tip precision--5.5/8.5, p = 0.003; iv) mucosal perforation reduction--3.5/7.5, p = 0.001; v) ablation efficiency tumors < 1.5 cm--6/9, p = 0.017; tumors > 1.5 cm--6.75/6.75, p = 1, and vi) overall efficiency--6/7.5, p = 0.09, for Holmium:YAG and TLA, respectively. The Thulium laser delivered non-inferior recurrence free survival to RIRS-UUT-TCC Holmium:YAG laser ablation, but better median parameter performance scores in fiber-tip stability, precision, reduced bleeding and mucosal perforation reduction in expert ratings. Despite improved photothermal coagulation, and endo-visualization for tumors < 1.5 cm, both ablation and overall efficiency remained challenging for larger tumors with both existing laser technologies.

8.76 W mid-infrared supercontinuum generation in a thulium doped fiber amplifier

NASA Astrophysics Data System (ADS)

Michalska, Maria; Grzes, Pawel; Swiderski, Jacek

2018-07-01

A stable mid-infrared supercontinuum (SC) generation with a maximum average power of 8.76 W in a spectral band of 1.9-2.65 μm is reported. To broaden the bandwidth of SC, a 1.55 μm pulsed laser system delivering 1 ns pulses at a pulse repetition frequency of 500 kHz was used as a seed source for one-stage thulium-doped fiber amplifier. The power conversion efficiency for wavelengths longer than 2.4 μm and 2.5 μm was determined to be 28% and 18%, respectively, which is believed to be the most efficient power distribution towards the mid-infrared in SC sources based on Tm-doped fibers. The power spectral density of the continuum was calculated to be >13 mW/nm with a potential of further scaling-up. A long-term power stability test, showing power fluctuations <3%, proved the robustness and reliability of the developed SC source.

Theoretical temperature-dependent branching ratios and laser thresholds of the 3F4 to 3H6 levels of Tm(3+) in ten garnets

NASA Technical Reports Server (NTRS)

Filer, Elizabeth D.; Barnes, Norman P.; Morrison, Clyde A.

1991-01-01

The calculated energy levels, the branching ratios, and the estimated thresholds for thulium operating on the 3F4 to 3H6 transitions are reported. Garnet materials with the general formula A3B2C3O12 are evaluated. Calculations are performed for the A side under the assumption of D2 symmetry. X-ray data available in the literature are used to evaluate the crystal-field components, A sub nm. Even-n components are employed to calculate the crystal-field splittings within the manifold. Thermal occupation factors are determined in a straightforward manner using a Boltzmann distribution for the respective manifolds. Odd-n components are applied to calculate the transition probabilities for electric field transitions. It is determined that the magnetic dipole contributions to the transition probability are comparable to the electric dipole contributions in some cases. Thresholds as a function of the density of thulium atoms are calculated.

Microsecond gain-switched master oscillator power amplifier (1958 nm) with high pulse energy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ke Yin; Weiqiang Yang; Bin Zhang

2014-02-28

An all-fibre master oscillator power amplifier (MOPA) emitting high-energy pulses at 1958 nm is presented. The seed laser is a microsecond gain-switched thulium-doped fibre laser (TDFL) pumped with a commercial 1550-nm pulsed fibre laser. The TDFL operates at a repetition rate f in the range of 10 to 100 kHz. The two-stage thulium-doped fibre amplifier is built to scale the energy of the pulses generated by the seed laser. The maximum output pulse energy higher than 0.5 mJ at 10 kHz is achieved which is comparable with the theoretical maximum extractable pulse energy. The slope efficiency of the second stagemore » amplifier with respect to the pump power is 30.4% at f = 10 kHz. The wavelength of the output pulse laser is centred near 1958 nm at a spectral width of 0.25 nm after amplification. Neither nonlinear effects nor significant amplified spontaneous emission (ASE) is observed in the amplification experiments. (lasers)« less

High-power thulium-doped fiber laser in an all-fiber configuration

NASA Astrophysics Data System (ADS)

Baravets, Yauhen; Todorov, Filip; Honzatko, Pavel

2016-12-01

High-power Tm-doped fiber lasers are greatly suitable for various applications, such as material processing, medicine, environmental monitoring and topography. In this work we present an all-fiber narrowband CW laser in near fundamental mode operation based on a Tm-doped double-clad active fiber pumped by 793 nm laser diodes with a central wavelength stabilized at 2039 nm by a fiber Bragg grating. The achieved output power is 60 W with a slope efficiency of 46%. The measured beam quality factor is less than 1.4. Further increasing of the output power is possible using various power scaling techniques, for example, coherent combination of several Tm-doped fiber lasers. The developed fiber laser could be employed for welding, cutting and marking of thermoplastics in industry, minimally invasive surgery in medicine or sensors in lidar systems. Future improvements of thulium fiber lasers are possible due to the extremely wide gain-bandwidth of the active medium and the rapid growth of 2-μm fiber components production.

High-power single-stage thulium-doped superfluorescent fiber source

NASA Astrophysics Data System (ADS)

Hu, Z. Y.; Yan, P.; Liu, Q.; Ji, E. C.; Xiao, Q. R.; Gong, M. L.

2015-01-01

In this paper, we report a high-power thulium (Tm)-doped superfluorescent fiber source (SFS) in the 2-μm spectral region. The SFS is based on double angle-cleaved facet operation and uses a simple single-stage geometry. The copropagating amplified spontaneous emission (ASE) yields a maximum output of 20.7 W at a center wavelength of 1,960.7 nm, with a full width at half maximum (FWHM) of ~45 nm. The counterpropagating ASE yields a maximum output of 25.2 W at a center wavelength of 1,948.2 nm, with a FWHM of ~50 nm. The maximum combined output of the SFS is as much as 45.9 W, which corresponds to a slope efficiency of 38.9 %. In addition, a model of the ~2 μm SFS in Tm-doped silica fibers pumped at ~790 nm is developed, and the influence of fiber length and end-facet reflectivity on the ASE output performance and the parasitic lasing threshold are studied numerically.

All-fiber thulium/holmium-doped mode-locked laser by tungsten disulfide saturable absorber

NASA Astrophysics Data System (ADS)

Yu, Hao; Zheng, Xin; Yin, Ke; Cheng, Xiang'ai; Jiang, Tian

2017-01-01

A passively mode-locked thulium/holmium-doped fiber laser (THDFL) based on tungsten disulfide (WS2) saturable absorber (SA) was demonstrated. The WS2 nanosheets were prepared by liquid phase exfoliation method and the SA was fabricated by depositing the few-layer WS2 nanosheets on the surface of a fiber taper. The modulation depth, saturable intensity, and non-saturable loss of this SA were measured to be 8.2%, 0.82 GW cm-2, and 29.4%, respectively. Based on this SA, a stable mode-locked laser operated at 1.91 µm was achieved with pulse duration of 825 fs and repetition rate of 15.49 MHz, and signal-to-noise ratio (SNR) of 67 dB. Meanwhile, by increasing the pump power and adjusting the position of polarization controller, harmonic mode-locking operations were obtained. These results showed that the WS2 nanosheet-based SA could be served as a desirable candidate for a short-pulse mode locker at 2 µm wavelength.

Thulium fiber laser damage to the ureter

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

2015-07-01

Our laboratory is studying experimental thulium fiber laser (TFL) as a potential alternative lithotripter to the clinical gold standard Holmium:YAG laser. Safety studies characterizing undesirable Holmium laser-induced damage to ureter tissue have been previously reported. Similarly, this study characterizes TFL induced ureter and stone basket damage. A TFL beam with pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rates of 150-500 Hz was delivered through a 100-μm-core, low-OH, silica optical fiber to the porcine ureter wall, in vitro. Ureter perforation times were measured and gross, histological, and optical coherence tomography images of the ablation zone were acquired. TFL operation at 150, 300, and 500 Hz produced mean ureter perforation times of 7.9, 3.8, and 1.8 s, respectively. Collateral damage averaged 510, 370, and 310 μm. TFL mean perforation time exceeded 1 s at each setting, which is a greater safety margin than previously reported during Holmium laser ureter perforation studies.

Thermochemistry of the gaseous fluorides of samarium, europium, and thulium

NASA Astrophysics Data System (ADS)

Kleinschmidt, P. D.; Lau, K. H.; Hildenbrand, D. L.

1981-01-01

The gaseous mono-, di-, and trifluorides of the lanthanide metals samarium, europium, and thulium were characterized thermochemically from high temperature equilibrium studies carried out by mass spectrometry. Reaction enthalpies and entropies were derived using second-law analysis throughout, and the results were used to evaluate the enthalpies of formation and bond dissociation energies (BDE) of the gaseous fluorides, and to obtain approximate values for the electronic entropies of the MF and MF2 species. The dissociation energies of the monofluorides D°0(SmF)=134 kcal/mole, D°0(EuF)=129 kcal/mole, and D°0(TmF)=121 kcal/mole, all ±2 kcal/mole, are in good agreement with values predicted by the Rittner electrostatic model, whereas values in the polyatomic fluorides show considerable variation and do not seem to follow any clear trends. Although the BDE values in some instances differ from previous estimates, their sums yield trifluoride heats of atomization that are in close accord with values derived from the vaporization thermodynamics of the solid trifluorides.

Continuous-wave broadly tunable Cr 2+:ZnSe laser pumped by a thulium fiber laser

NASA Astrophysics Data System (ADS)

Sennaroglu, Alphan; Demirbas, Umit; Vermeulen, Nathalie; Ottevaere, Heidi; Thienpont, Hugo

2006-12-01

We describe a compact, broadly tunable, continuous-wave (cw) Cr 2+:ZnSe laser pumped by a thulium fiber laser at 1800 nm. In the experiments, a polycrystalline ZnSe sample with a chromium concentration of 9.5 × 10 18 cm -3 was used. Free-running laser output was around 2500 nm. Output couplers with transmissions of 3%, 6%, and 15% were used to characterize the power performance of the laser. Best power performance was obtained with a 15% transmitting output coupler. In this case, as high as 640 mW of output power was obtained with 2.5 W of pump power at a wavelength of 2480 nm. The stimulated emission cross-section values determined from laser threshold data and emission measurements were in good agreement. Finally, broad, continuous tuning of the laser was demonstrated between 2240 and 2900 nm by using an intracavity Brewster cut MgF 2 prism and a single set of optics.

Efficient Single-Frequency Thulium Doped Fiber Laser Near 2-micrometers

NASA Technical Reports Server (NTRS)

Geng, Jihong; Wu, Jianfeng; Jiang, Shibin; Yu, Jirong

2007-01-01

We demonstrate highly efficient diode-pumped single-frequency fiber laser with 35% slope efficiency and 50mW output power operating near 2 micrometers, which generated from a 2-cm long piece of highly Tm(3+)-doped germanate glass fiber pumped at 800nm.

Switchable thulium-doped fiber laser from polarization rotation vector to scalar soliton

NASA Astrophysics Data System (ADS)

Wu, Zhichao; Fu, Songnian; Jiang, Kai; Song, Jue; Li, Huizi; Tang, Ming; Shum, Ping; Liu, Deming

2016-10-01

We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect. The scalar solitons and PRLVSs possess 3-dB optical spectrum bandwidth of 2.2 nm and 2 nm, pulse-width of 1.8 ps and 2 ps, respectively. Moreover, the PRLVSs demonstrate a typical energy exchange between two polarized components on optical spectra and a period-doubling feature in time domain. Such operation principle can also be used in 1550 nm band fiber lasers and other nonlinear systems.

Switchable thulium-doped fiber laser from polarization rotation vector to scalar soliton

PubMed Central

Wu, Zhichao; Fu, Songnian; Jiang, Kai; Song, Jue; Li, Huizi; Tang, Ming; Shum, Ping; Liu, Deming

2016-01-01

We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect. The scalar solitons and PRLVSs possess 3-dB optical spectrum bandwidth of 2.2 nm and 2 nm, pulse-width of 1.8 ps and 2 ps, respectively. Moreover, the PRLVSs demonstrate a typical energy exchange between two polarized components on optical spectra and a period-doubling feature in time domain. Such operation principle can also be used in 1550 nm band fiber lasers and other nonlinear systems. PMID:27708427

Switchable thulium-doped fiber laser from polarization rotation vector to scalar soliton.

PubMed

Wu, Zhichao; Fu, Songnian; Jiang, Kai; Song, Jue; Li, Huizi; Tang, Ming; Shum, Ping; Liu, Deming

2016-10-06

We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide joint contribution for passive mode-locking operation. By finely adjusting the polarization to alter the strength of NPR-based saturable absorption, the TDFL either approaches the operation regime of scalar soliton with strong NPR effect, or generates polarization rotation locked vector soliton (PRLVS) with weak NPR effect. The scalar solitons and PRLVSs possess 3-dB optical spectrum bandwidth of 2.2 nm and 2 nm, pulse-width of 1.8 ps and 2 ps, respectively. Moreover, the PRLVSs demonstrate a typical energy exchange between two polarized components on optical spectra and a period-doubling feature in time domain. Such operation principle can also be used in 1550 nm band fiber lasers and other nonlinear systems.

Structural and optical study on antimony-silicate glasses doped with thulium ions.

PubMed

Dorosz, D; Zmojda, J; Kochanowicz, M; Miluski, P; Jelen, P; Sitarz, M

2015-01-05

Structural, spectroscopic and thermal properties of SiO₂-Al₂O₃-Sb₂O₃-Na₂O glass system doped with 0.2 mol% Tm₂O₃ have been presented. Synthesis of antimony-silicate glasses with relatively low phonon energy (600 cm(-1), which implicates a small non-radiative decay rate) was performed by conventional high-temperature melt-quenching methods. The effect of SiO₂/Sb₂O₃ ratio in fabricated Tm(3+) doped glass on thermal, structural and luminescence properties was investigated. On the basis of structural investigations decomposition of absorption bands in the infrared FTIR region was performed, thus determining that antimony ions are the only glass-forming ions, setting up the lattice of fabricated glasses. Luminescence band at the wavelength of 1.8 μm corresponding to (3)F₄→(3)H₆ transition in thulium ions was obtained under 795 nm laser pumping. It was observed that combination of relatively low phonon energy and greater separation of optically active centers in the fabricated glasses influenced in decreasing the luminescence intensity at 1800 nm. Copyright © 2014 Elsevier B.V. All rights reserved.

Miniaturized Lab System for Future Cold Atom Experiments in Microgravity

NASA Astrophysics Data System (ADS)

Kulas, Sascha; Vogt, Christian; Resch, Andreas; Hartwig, Jonas; Ganske, Sven; Matthias, Jonas; Schlippert, Dennis; Wendrich, Thijs; Ertmer, Wolfgang; Maria Rasel, Ernst; Damjanic, Marcin; Weßels, Peter; Kohfeldt, Anja; Luvsandamdin, Erdenetsetseg; Schiemangk, Max; Grzeschik, Christoph; Krutzik, Markus; Wicht, Andreas; Peters, Achim; Herrmann, Sven; Lämmerzahl, Claus

2017-02-01

We present the technical realization of a compact system for performing experiments with cold 87Rb and 39K atoms in microgravity in the future. The whole system fits into a capsule to be used in the drop tower Bremen. One of the advantages of a microgravity environment is long time evolution of atomic clouds which yields higher sensitivities in atom interferometer measurements. We give a full description of the system containing an experimental chamber with ultra-high vacuum conditions, miniaturized laser systems, a high-power thulium-doped fiber laser, the electronics and the power management. In a two-stage magneto-optical trap atoms should be cooled to the low μK regime. The thulium-doped fiber laser will create an optical dipole trap which will allow further cooling to sub- μK temperatures. The presented system fulfills the demanding requirements on size and power management for cold atom experiments on a microgravity platform, especially with respect to the use of an optical dipole trap. A first test in microgravity, including the creation of a cold Rb ensemble, shows the functionality of the system.

High-quality single-crystal thulium iron garnet films with perpendicular magnetic anisotropy by off-axis sputtering

NASA Astrophysics Data System (ADS)

Wu, C. N.; Tseng, C. C.; Lin, K. Y.; Cheng, C. K.; Yeh, S. L.; Fanchiang, Y. T.; Hong, M.; Kwo, J.

2018-05-01

High-quality single-crystal thulium iron garnet (TmIG) films of 10-30 nm thick were grown by off-axis sputtering at room temperature (RT) followed by post-annealing. X-ray photoelectron spectroscopy (XPS) was employed to determine the TmIG film composition to optimize the growth conditions, along with the aid of x-ray diffraction (XRD) structural analysis and atomic force microscope (AFM) for surface morphology. The optimized films exhibited perpendicular magnetic anisotropy (PMA) and the saturation magnetization at RT was ˜99 emu/cm3, close to the RT bulk value ˜110 emu/cm3 with a very low coercive field of ˜2.4 Oe. We extracted the H⊥ of 1734 Oe and the peak-to-peak linewidth ΔH of ferromagnetic resonance are only about 99 Oe, significantly lower than that of PLD grown TmIG film and bulk single crystals. The high-quality sputtered single-crystal TmIG films show great potential to be integrated with topological insulators or heavy metals with strong spin-orbit coupling for spintronic applications.

Safety and effectiveness of Thulium VapoEnucleation of the prostate (ThuVEP) in patients on anticoagulant therapy.

PubMed

Netsch, Christopher; Stoehrer, M; Brüning, M; Gabuev, A; Bach, T; Herrmann, T R W; Gross, A J

2014-02-01

To evaluate the safety and efficacy of Thulium VapoEnucleation of the prostate (ThuVEP) for patients on oral anticoagulants (OA) with symptomatic benign prostatic obstruction (BPO). Fifty-six patients, undergoing ThuVEP at two institutions, were evaluated from May 2009 until June 2011. All patients were at high cardiopulmonary risk and presented with a median American Society of Anesthesiology score of 3 [interquartile range (IQR) 2-3]. Thirty-two patients were on aspirin, 8 were on clopidogrel or clopidogrel and aspirin, and 16 on phenprocoumon at the time of surgery. Patient demographic, perioperative, and follow-up data were analyzed. Median prostate volume was 50 (IQR 34-76) cc, and resected tissue weight was 32 (IQR 20-50) g. The median operative time was 61.5 (IQR 40-100.75) min, and the catheter time 2 (IQR 2-3) days. There were no perioperative thromboembolic events. Five patients (8.9%) required a second-look operation in the immediate postoperative course (hemorrhage n = 4, residual adenoma n = 1) and four (7.1%) blood transfusions. Complications within the first 30 days included urinary tract infections (1.7%), urinary retention (3.6%), and delayed bleeding (7.1%). These complications were managed conservatively. At 12-month follow-up, median QoL [5 (IQR 3.75-5) vs. 1 (IQR 1-2)], IPSS [21.5 (IQR 15.5-23.75) vs. 5 (IQR 3-8)], Qmax [7.7 (IQR 6.3-10) vs. 28.3 (IQR 21.25-39.2) ml/s], and postvoiding residual urine [100 (IQR 46-200) vs. 17.5 (IQR 0-36) ml] improved significantly (p < 0.002). Thulium VapoEnucleation of the prostate seems to be a safe and efficacious procedure for the treatment of symptomatic BPO in patients at high cardiopulmonary risk on OA.

Rare Earths; The Fraternal Fifteen (Rev.)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gschneidner, Jr., Karl A.

1966-01-01

Rare earths are a set of 15 elements: lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. They are not rare and not earths; they are metals and quite abundant. They are studied to develop commercial products which are beneficial to mankind, and because some rare earths are important to fission products.

10 CFR 30.72 - Schedule C-Quantities of radioactive materials requiring consideration of the need for an...

Code of Federal Regulations, 2012 CFR

2012-01-01

...-127m .01 5,000 Tellurium-129m .01 5,000 Terbium-160 .01 4,000 Thulium-170 .01 4,000 Tin-113 .01 10,000 Tin-123 .01 3,000 Tin-126 .01 1,000 Titanium-44 .01 100 Vanadium-48 .01 7,000 Xenon-133 1.0 900,000...

10 CFR 30.72 - Schedule C-Quantities of radioactive materials requiring consideration of the need for an...

Code of Federal Regulations, 2013 CFR

2013-01-01

...-127m .01 5,000 Tellurium-129m .01 5,000 Terbium-160 .01 4,000 Thulium-170 .01 4,000 Tin-113 .01 10,000 Tin-123 .01 3,000 Tin-126 .01 1,000 Titanium-44 .01 100 Vanadium-48 .01 7,000 Xenon-133 1.0 900,000...

10 CFR 30.72 - Schedule C-Quantities of radioactive materials requiring consideration of the need for an...

Code of Federal Regulations, 2014 CFR

2014-01-01

...-127m .01 5,000 Tellurium-129m .01 5,000 Terbium-160 .01 4,000 Thulium-170 .01 4,000 Tin-113 .01 10,000 Tin-123 .01 3,000 Tin-126 .01 1,000 Titanium-44 .01 100 Vanadium-48 .01 7,000 Xenon-133 1.0 900,000...

Cavitation bubble dynamics during thulium fiber laser lithotripsy

NASA Astrophysics Data System (ADS)

Hardy, Luke A.; Kennedy, Joshua D.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

2016-02-01

The Thulium fiber laser (TFL) is being explored for lithotripsy. TFL parameters differ from standard Holmium:YAG laser in several ways, including smaller fiber delivery, more strongly absorbed wavelength, low pulse energy/high pulse rate operation, and more uniform temporal pulse structure. High speed imaging of cavitation bubbles was performed at 105,000 fps and 10 μm spatial resolution to determine influence of these laser parameters on bubble formation. TFL was operated at 1908 nm with pulse energies of 5-75 mJ, and pulse durations of 200-1000 μs, delivered through 100-μm-core fiber. Cavitation bubble dynamics using Holmium laser at 2100 nm with pulse energies of 200-1000 mJ and pulse duration of 350 μs was studied, for comparison. A single, 500 μs TFL pulse produced a bubble stream extending 1090 +/- 110 μm from fiber tip, and maximum bubble diameters averaged 590 +/- 20 μm (n=4). These observations are consistent with previous studies which reported TFL ablation stallout at working distances < 1.0 mm. TFL bubble dimensions were five times smaller than for Holmium laser due to lower pulse energy, higher water absorption coefficient, and smaller fiber diameter used.

Titanium Dioxide (TiO2) film as a new saturable absorber for generating mode-locked Thulium-Holmium doped all-fiber laser

NASA Astrophysics Data System (ADS)

Mohd Rusdi, Muhammad Farid; Latiff, Anas Abdul; Paul, Mukul Chandra; Das, Shyamal; Dhar, Anirban; Ahmad, Harith; Harun, Sulaiman Wadi

2017-03-01

We report the generation of mode-locked thulium-holmium doped fiber laser (THDFL) at 1979 nm. This is a first demonstration of mode-locked by using Titanium Dioxide (TiO2) film as a saturable absorber (SA). A piece of 1 mm×1 mm TiO2 film was sandwiched in between two fiber ferrule in the cavity. Fabrication process of TiO2 film incorporated a TiO2 and a polyvinyl alcohol (PVA). The stable 9 MHz repetition rate of mode-locked mode operation with 58 dB SNR was generated under pump power of 902-1062 mW. At maximum pump power, the mode-locked THDFL has output power and pulse energy of 15 mW and 1.66 nJ, respectively. Our results demonstrate the TiO2 can be used promisingly in ultrafast photonics applications.

A Miniaturized, 1.9F Integrated Optical Fiber and Stone Basket for Use in Thulium Fiber Laser Lithotripsy.

PubMed

Wilson, Christopher R; Hutchens, Thomas C; Hardy, Luke A; Irby, Pierce B; Fried, Nathaniel M

2015-10-01

The thulium fiber laser (TFL) is being explored as an alternative laser lithotripter to the standard holmium:yttrium-aluminum-garnet laser. The more uniform beam profile of the TFL enables higher power transmission through smaller fibers. In this study, a 100-μm core, 140-μm outer-diameter (OD) silica fiber with 5-mm length hollow steel tip was integrated with 1.3F (0.433-mm OD) nitinol wire basket to form a 1.9F (0.633-mm OD) device. TFL energy of 30 mJ, 500 μs pulse duration, and 500 Hz pulse rate was delivered to human uric acid stones, ex vivo. Stone ablation rates measured 1.5 ± 0.2 mg/s, comparable to 1.7 ± 0.3 mg/s using bare fiber tips separately with stone basket. With further development, this device may minimize stone retropulsion, allowing more efficient TFL lithotripsy at higher pulse rates. It may also provide increased flexibility, higher saline irrigation rates through the ureteroscope working channel, reduce fiber degradation compared with separate fiber and basket manipulation, and reduce laser-induced nitinol wire damage.

High-pressure phase transitions in rare earth metal thulium to 195 GPa.

PubMed

Montgomery, Jeffrey M; Samudrala, Gopi K; Tsoi, Georgiy M; Vohra, Yogesh K

2011-04-20

We have performed image plate x-ray diffraction studies on a heavy rare earth metal, thulium (Tm), in a diamond anvil cell to a pressure of 195 GPa and volume compression V/V₀ = 0.38 at room temperature. The rare earth crystal structure sequence, hcp →Sm-type→ dhcp →fcc → distorted fcc, is observed in Tm below 70 GPa with the exception of a pure fcc phase. The focus of our study is on the ultrahigh-pressure phase transition and Rietveld refinement of crystal structures in the pressure range between 70 and 195 GPa. The hexagonal hR-24 phase is seen to describe the distorted fcc phase between 70 and 124 GPa. Above 124 ± 4 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of -1.5%. The equation of state data shows rapid stiffening above the phase transition at 124 GPa and is indicative of participation of f-electrons in bonding. We compare the behavior of Tm to other heavy rare-earths and heavy actinide metals under extreme conditions of pressure.

High-pressure phase transitions in rare earth metal thulium to 195 GPa

NASA Astrophysics Data System (ADS)

Montgomery, Jeffrey M.; Samudrala, Gopi K.; Tsoi, Georgiy M.; Vohra, Yogesh K.

2011-04-01

We have performed image plate x-ray diffraction studies on a heavy rare earth metal, thulium (Tm), in a diamond anvil cell to a pressure of 195 GPa and volume compression V/Vo = 0.38 at room temperature. The rare earth crystal structure sequence, {hcp}\\to {Sm {-}type} \\to {dhcp} \\to {fcc} \\to distorted fcc, is observed in Tm below 70 GPa with the exception of a pure fcc phase. The focus of our study is on the ultrahigh-pressure phase transition and Rietveld refinement of crystal structures in the pressure range between 70 and 195 GPa. The hexagonal hR- 24 phase is seen to describe the distorted fcc phase between 70 and 124 GPa. Above 124 ± 4 GPa, a structural transformation from hR 24 phase to a monoclinic C 2/m phase is observed with a volume change of - 1.5%. The equation of state data shows rapid stiffening above the phase transition at 124 GPa and is indicative of participation of f-electrons in bonding. We compare the behavior of Tm to other heavy rare-earths and heavy actinide metals under extreme conditions of pressure.

Comparative laser-tissue interaction effects at 1.96 and 2.01 um of Cr; Tm:YAG laser

NASA Astrophysics Data System (ADS)

Pankratov, Michail M.; Perrault, Donald F., Jr.; Shapshay, Stanley M.; Pinto, Joseph F.; Esterowitz, Dina; Aretz, H. Thomas

1992-08-01

A pulsed spiking and nonspiking Cr; thulium (Tm):YAG flash lamp pumped laser operating at 1.96 and 2.01 μm was investigated in vitro in the clinically relevant power range for its basic laser-tissue interaction with soft, cartilaginous, and bone tissues. Some explanations of the differences and possible medical applications are discussed.

OSL properties of KMgF3:Tm3+ for dosimetric applications as OSL dosimeter.

PubMed

Camargo, Luis; Cruz, Lituania Pérez; Cruz-Zaragoza, Epifanio; Ovalle, Segundo Martínez; Marcazzó, Julián

2018-04-06

The optically stimulated luminescence (OSL) properties of undoped and Tm 3+ -doped KMgF 3 fluoroperovskite have been investigated for the first time. KMgF 3 compounds were synthesized by solid state reaction method and two different procedures were employed to improve the contact among the reagents, namely, the compressed powder was put either in an alumina crucible or in a platinum foil. The maximum OSL emission was found in samples prepared in an alumina crucible and doped with 0.5% mol of thulium. The radioluminescence (RL) spectrum shows two emission peaks at 455 and 360 nm, which can be ascribed to the 1 D 2 - 3 F 4 and 1 D 2 - 3 H 6 transitions of Tm 3+ cations. The OSL dosimetric properties of the most promising composition, namely, KMgF 3 :Tm 3+ (0.5% mol), have also been determined and analyzed. This compound exhibits good linearity in the dose range from 0.1 up to 100 Gy and satisfactory repeatability with a percentage standard deviation of 2.4%. Therefore, an OSL fading of approximately 75% in the first 36 h of storage is observed and then, the response remains almost constant. These characteristics, together with a minimum detectable dose of 0.04 Gy and the rapid erasing of the OSL signal after 100 s of stimulation, which makes feasible to bleach completely the residual OSL in order to restore the sample between dose measurements, suggest the potential of this perovskite as OSL dosimeter. Copyright © 2018 Elsevier Ltd. All rights reserved.

Rare Earth Element Concentrations in Geothermal Wells at the Puna Geothermal Field, Hawaii

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fowler, Andrew; Zierenberg, Robert

Rare earth element concentrations in the geothermal wells at the Puna geothermal field, Hawaii. Samples taken from geothermal wells KS-5, KS-6W, KS-9W, KS-14E, and KS-16N. Includes pH and concentrations for Cerium, Dysprosium, Erbium, Europium, Gadolinium, Holmium, Lanthanum, Lutetium, Neodymium, Praseodymium, Samarium, Terbium, Thulium, Yttrium, and Ytterbium. Samples collected on November 11-17, 2016.

Efficient, space-based, PM 100W thulium fiber laser for pumping Q-switched 2μm Ho:YLF for global winds and carbon dioxide lidar

NASA Astrophysics Data System (ADS)

Engin, Doruk; Mathason, Brian; Storm, Mark

2017-08-01

Global wind measurements are critically needed to improve and extend NOAA weather forecasting that impacts U.S. economic activity such as agriculture crop production, as well as hurricane forecasting, flooding, and FEMA disaster planning.1 NASA and the 2007 National Research Council (NRC) Earth Science Decadal Study have also identified global wind measurements as critical for global change research. NASA has conducted aircraft-based wind lidar measurements using 2 um Ho:YLF lasers, which has shown that robust wind measurements can be made. Fibertek designed and demonstrated a high-efficiency, 100 W average power continuous wave (CW) 1940 nm thulium (Tm)- doped fiber laser bread-board system meeting all requirements for a NASA Earth Science spaceflight 2 μm Ho:YLF pump laser. Our preliminary design shows that it is possible to package the laser for high-reliability spaceflight operation in an ultra-compact 2″x8″x14″ size and weight <8.5 lbs. A spaceflight 100 W polarization maintaining (PM) Tm laser provides a path to space for a pulsed, Q-switched 2 μm Ho:YLF laser with 30-80 mJ/pulse range at 100-200 Hz repletion rates.

Cholesterol-diethylenetriaminepentaacetate complexed with thulium ions integrated into bicelles to increase their magnetic alignability.

PubMed

Liebi, Marianne; Kuster, Simon; Kohlbrecher, Joachim; Ishikawa, Takashi; Fischer, Peter; Walde, Peter; Windhab, Erich J

2013-11-27

Lanthanides have been used for several decades to increase the magnetic alignability of bicelles. DMPE-DTPA (1,2-dimyristoyl-sn-glycero-3-phospho-ethanolamine-diethylenetriaminepentaacetate) is commonly applied to anchor the lanthanides into the bicelles. However, because DMPE-DTPA has the tendency to accumulate at the highly curved edge region of the bicelles and if located there does not contribute to the magnetic orientation energy, we have tested cholesterol-DTPA complexed with thulium ions (Tm(3+)) as an alternative chelator to increase the magnetic alignability. Differential scanning calorimetric (DSC) measurements indicate the successful integration of cholesterol-DTPA into a DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) bilayer. Cryo transmission electron microscopy and small-angle neutron scattering (SANS) measurements show that the disklike structure, that is, bicelles, is maintained if cholesterol-DTPA·Tm(3+) is integrated into a mixture of DMPC, cholesterol, and DMPE-DTPA·Tm(3+). The size of the bicelles is increased compared to the size of the bicelles obtained from mixtures without cholesterol-DTPA·Tm(3+). Magnetic-field-induced birefringence and SANS measurements in a magnetic field show that with addition of cholesterol-DTPA·Tm(3+) the magnetic alignability of these bicelles is significantly increased compared to bicelles composed of DMPC, cholesterol, and DMPE-DTPA·Tm(3+) only.

CNT-based saturable absorbers with scalable modulation depth for Thulium-doped fiber lasers operating at 1.9 μm

PubMed Central

Sobon, Grzegorz; Duzynska, Anna; Świniarski, Michał; Judek, Jarosław; Sotor, Jarosław; Zdrojek, Mariusz

2017-01-01

In this work, we demonstrate a comprehensive study on the nonlinear parameters of carbon nanotube (CNT) saturable absorbers (SA) as a function of the nanotube film thickness. We have fabricated a set of four saturable absorbers with different CNT thickness, ranging from 50 to 200 nm. The CNTs were fabricated via a vacuum filtration technique and deposited on fiber connector end facets. Each SA was characterized in terms of nonlinear transmittance (i.e. optical modulation depth) and tested in a Thulium-doped fiber laser. We show, that increasing the thickness of the CNT layer significantly increases the modulation depth (up to 17.3% with 200 nm thick layer), which strongly influences the central wavelength of the laser, but moderately affects the pulse duration. It means, that choosing the SA with defined CNT thickness might be an efficient method for wavelength-tuning of the laser, without degrading the pulse duration. In our setup, the best performance in terms of bandwidth and pulse duration (8.5 nm and 501 fs, respectively) were obtained with 100 nm thick CNT layer. This is also, to our knowledge, the first demonstration of a fully polarization-maintaining mode-locked Tm-doped laser based on CNT saturable absorber. PMID:28368014

Modulated and continuous-wave operations of low-power thulium (Tm:YAP) laser in tissue welding

NASA Astrophysics Data System (ADS)

Bilici, Temel; Tabakoğlu, Haşim Özgür; Topaloğlu, Nermin; Kalaycıoğlu, Hamit; Kurt, Adnan; Sennaroglu, Alphan; Gülsoy, Murat

2010-05-01

Our aim is to explore the welding capabilities of a thulium (Tm:YAP) laser in modulated and continuous-wave (CW) modes of operation. The Tm:YAP laser system developed for this study includes a Tm:YAP laser resonator, diode laser driver, water chiller, modulation controller unit, and acquisition/control software. Full-thickness incisions on Wistar rat skin were welded by the Tm:YAP laser system at 100 mW and 5 s in both modulated and CW modes of operation (34.66 W/cm2). The skin samples were examined during a 21-day healing period by histology and tensile tests. The results were compared with the samples closed by conventional suture technique. For the laser groups, immediate closure at the surface layers of the incisions was observed. Full closures were observed for both modulated and CW modes of operation at day 4. The tensile forces for both modulated and CW modes of operation were found to be significantly higher than the values found by conventional suture technique. The 1980-nm Tm:YAP laser system operating in both modulated and CW modes maximizes the therapeutic effect while minimizing undesired side effects of laser tissue welding. Hence, it is a potentially important alternative tool to the conventional suturing technique.

Graphene-PVA saturable absorber for generation of a wavelength-tunable passively Q-switched thulium-doped fiber laser in 2.0 µm

NASA Astrophysics Data System (ADS)

Ahmad, H.; Samion, M. Z.; Sharbirin, A. S.; Norizan, S. F.; Aidit, S. N.; Ismail, M. F.

2018-05-01

Graphene, a 2D material, has been used for generation of pulse lasers due to the presence of its various fascinating optical properties compared to other materials. Hence in this paper, we report the first demonstration of a thulium doped fiber laser with a wavelength-tunable, passive Q-switched output using a graphene-polyvinyl-alcohol composite film for operation in the 2.0 µm region. The proposed laser has a wavelength-tunable output spanning from 1932.0 nm to 1946.0 nm, giving a total tuning range of 14.0 nm. The generated pulse has a maximum repetition rate and average output power of 36.29 kHz and 0.394 mW at the maximum pump power of 130.87 mW, as well as a pulse width of 6.8 µs at this pump power. The generated pulses have a stable output, having a signal-to-noise ratio of 31.75 dB, and the laser output is stable when tested over a period of 60 min. The proposed laser would have multiple applications for operation near the 2.0 micron region, especially for bio-medical applications and range-finding.

Photothermal effect of infrared lasers on ex vivo lamb brain tissues

NASA Astrophysics Data System (ADS)

Özgürün, Baturay; Gülsoy, Murat

2018-02-01

Here, the most suitable infrared laser for a neurosurgery operation is suggested, among 1940-nm thulium fiber, 1470-nm diode, 1070-nm ytterbium fiber and 980-nm diode lasers. Cortical and subcortical ex-vivo lamb brain tissues are exposed to the laser light with the combinations of some laser parameters such as output power, energy density, operation mode (continuous and pulsed-modulated) and operation time. In this way, the greatest ablation efficiency associated with the best neurosurgical laser type can be defined. The research can be divided into two parts; pre-dosimetry and dosimetry studies. The former is used to determine safe operation zones for the dosimetry study by defining coagulation and carbonization onset times for each of the brain tissues. The latter is the main part of this research, and both tissues are exposed to laser irradiation with various energy density levels associated with the output power and operation time. In addition, photo-thermal effects are compared for two laser operation modes, and then coagulation and ablation diameters to calculate the ablation efficiency are measured under a light microscope. Consequently, results are compared graphically and statistically, and it is found that thulium and 1470-nm diode lasers can be utilized as subcortical and cortical tissue ablator devices, respectively.

Therapeutic applications of lasers in urology: an update.

PubMed

Fried, Nathaniel M

2006-01-01

There has been renewed interest in the use of lasers for minimally invasive treatment of urologic diseases in recent years. The introduction of more compact, higher power, less expensive and more user-friendly solid-state lasers, such as the holmium:yttrium-aluminum-garnet (YAG), frequency-doubled neodymium:YAG and diode lasers has made the technology more attractive for clinical use. The availability of small, flexible, biocompatible, inexpensive and disposable silica optical fiber delivery systems for use in flexible endoscopes has also promoted the development of new laser procedures. The holmium:YAG laser is currently the workhorse laser in urology since it can be used for multiple soft- and hard-tissue applications, including laser lithotripsy, benign prostate hyperplasia, bladder tumors and strictures. More recently, higher power potassium-titanyl-phosphate lasers have been introduced and show promise for the treatment of benign prostatic hyperplasia. On the horizon, newer and more effective photosensitizing drugs are being tested for potential use in photodynamic therapy of bladder and prostate cancer. Additionally, new experimental lasers such as the erbium:YAG, Thulium and Thulium fiber lasers, may provide more precise incision of soft tissues, more efficient laser lithotripsy and more rapid prostate ablation. This review provides an update on the most important new clinical and experimental therapeutic applications of lasers in urology over the past 5 years.

Finasteride accelerates prostate wound healing after thulium laser resection through DHT and AR signalling.

PubMed

Zhao, Ruizhe; Wang, Xingjie; Jiang, Chenyi; Shi, Fei; Zhu, Yiping; Yang, Boyu; Zhuo, Jian; Jing, Yifeng; Luo, Guangheng; Xia, Shujie; Han, Bangmin

2018-06-01

Urinary tract infection, urinary frequency, urgency, urodynia and haemorrhage are common post-operative complications of thulium laser resection of the prostate (TmLRP). Our study mainly focuses on the role of finasteride in prostate wound healing through AR signalling. TmLRP beagles were randomly distributed into different treatment groups. Serum and intra-prostatic testosterone and DHT level were determined. Histological analysis was conducted to study the re-epithelialization and inflammatory response of the prostatic urethra in each group. We investigated the role of androgen in proliferation and inflammatory response in prostate. In addition, the effects of TNF-α on prostate epithelium and stromal cells were also investigated. Testosterone and DHT level increased in testosterone group and DHT decreased in finasteride group. Accelerated wound healing of prostatic urethra was observed in the finasteride group. DHT suppressed proliferation of prostate epithelium and enhanced inflammatory response in prostate. We confirmed that DHT enhanced macrophages TNF-α secretion through AR signalling. TNF-α suppressed proliferation of prostate epithelial cells and retarded cell migration. TNF-α also played a pivotal role in suppressing fibroblasts activation and contraction. Testosterone treatment repressed re-epithelialization and wound healing of prostatic urethra. Finasteride treatment may be an effective way to promote prostate re-epithelialization. © 2017 John Wiley & Sons Ltd.

A multidisciplinary approach to the identification and evaluation of novel concepts for deeply buried hardened target defeat

NASA Astrophysics Data System (ADS)

Branscome, Ewell Caleb

During the Cold War, Deeply Buried Hardened Targets (DBHTs) and the assets they protected were of great strategic and tactical concern to the Department of Defense. Megaton-class nuclear warheads were the only viable means of attacking many of these facilities, and even so, a small subset of DBHTs was anticipated to be robust even in the face of such an attack. Post Cold War, the threat posed by DBHTs has not disappeared. Rather, the conventional warfare advantages of the United States have led to an increasing emphasis by potential adversaries on the construction and use of hardened facilities such as DBHTs for protection of both conventional and unconventional assets. Further, the shift in perceived relative risk to the United States' national security from large scale all-out nuclear attack towards very limited attack by Weapons of Mass Destruction (WMD) has led some to hypothesize that "self-deterrence" may diminish the strategic value of current inventory nuclear weapons. The objective of the work described was to identify and explore a paradigm shifting solution that could offer leap-ahead capabilities to counter current and future DBHT threats while mitigating or eliminating the "self-deterrence" issue. Systematic evaluation of DHBT defeat alternatives lead to the selection of a thermal subterrene as a hypothetical means of providing such a capability. A number of possible implementation alternatives for a thermal subterrene were investigated, resulting in the identification of the RadioIsotope Powered Thermal Penetrator (RIPTP) concept for providing an effectively unlimited hard rock penetration capability using near-term technologies. However, the proposed approach was novel and thus required formulation and application of a physics based multidisciplinary analysis code to enable evaluation of lv design alternatives and analysis of performance. Technical considerations identified as important to the feasibility of a RIPTP for DBHT defeat included: packing of RIPTP components in available volume; close-contact melting in a medium with nonlinear thermodynamic properties; radiation shielding; radiation health physics; point source plume dispersal calculations; alternative technologies for production of radioisotopes; chemical and physical properties of isotope compounds; nuclear reactor characteristics; high temperature material stability and inter-material compatibility; weapon and delivery system integration; a variety of heat transfer regimes including radiation, conduction, convection, nucleate boiling, and film boiling; thermal/mechanical stress analysis (steady-state and transient); rock physical and thermodynamic properties as a function of temperature; detection/mapping of deeply buried facility spaces; and more. The following disciplinary analyses were composed into a multidisciplinary analysis code for a RIPTP: packing of RIPTP components in available volume; close-contact melting analysis; transmutation of isotope species by neutron activation; reactor neutron economy; radioisotope power generation through decay; metamodelled radiation shielding calculations for a RIPTP; and steady state thermal analyses for a RIPTP in various scenarios. Filtering of radioisotopes for potential suitability, their possible production mechanisms, state of technological development, and multidisciplinary analysis code predicted performance lead to the identification of Thulium-170 as the best isotope for powering a RIPTP using present-day technology and technical data. Ytterbium-169 was identified as an alternative isotope offering the potential for significant potential improvements over Thulium-170 in radiological safety as well as RIPTP performance and producibility. Production, however, was determined to require identification of a cost effective technology for highly enriching Ytterbium-168 from its low natural abundance. Performance analysis of the identified baseline Thulium-170 RIPTP suggested that the predicted low penetration rate of about 10 meters/day could be a significant negative factor with regards to possible viability of the concept. Consequently, a survey for potentially enabling technologies was performed using an adaptation of the Technology Impact Forecasting (TIF) approach. It was found that the greatest potential for improving performance of the baseline Thulium-170 RIPTP resulted from increasing overall power density of the penetrator. Several possible technology approaches to achieving significantly increased penetration rates (approximately 50 meters/day expected penetration rate vs. original 13 meters/day) were proposed. However, it was determined that the hypothetical technology having the greatest potential impact on thermal subterrene viability for DHBT defeat with respect to penetration rate was cost-effective enrichment for Ytterbium-168. Development of such a technology would eliminate or enormously reduce the impact of all identified RIPTP performance and producibility concerns. Alternatively, relaxation of the requirement for no radiological hazard to enemy combatants would enable selection of a fissile powered thermal subterrene to provide required power densities consistent with rapid penetration.

Widely tunable 1.94-μm Tm:BaY2F8 laser

NASA Astrophysics Data System (ADS)

Galzerano, Gianluca; Cornacchia, Francesco; Parisi, Daniela; Toncelli, Alessandra; Tonelli, Mauro; Laporta, Paolo

2005-04-01

A novel BaY2F8 crystal doped with thulium ions is grown and extensively investigated. Owing to the large number of vibronic levels and to a favorable electron-phonon coupling, extremely wide absorption and emission bands around 1.9 μm are observed. A room-temperature Tm:BaY2F8 laser tunable over a 210-nm interval, from 1849 to 2059 nm, is demonstrated.

Generation of bound states of pulses in a SESAM mode-locked Cr:ZnSe laser

NASA Astrophysics Data System (ADS)

Bu, Xiangbao; Shi, Yuhang; Xu, Jia; Li, Huijuan; Wang, Pu

2018-06-01

We report on the generation of bound states of pulses in a SESAM mode-locked Cr:ZnSe laser around 2415 nm. A thulium-doped double-clad fiber laser at 1908 nm was used as the pump source. Bound states with various pulse separations at different dispersion regimes were obtained. Especially, in the anomalous dispersion regime, vibrating bound state of solitons exhibiting an evolving phase was obtained.

Rare Earth Element Concentrations from Wells at the Don A. Campbell Geothermal Plant, Nevada

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fowler, Andrew; Zierenberg, Robert

* Requires permission of originators for use. Rare earth element concentrations in thermal springs from the wells at the Don A. Campbell geothermal plant, Nevada. Samples taken from geothermal wells 85-11, 65-11, 54-11, and 64-11. Includes pH and concentrations for Cerium, Dysprosium, Erbium, Europium, Gadolinium, Holmium, Lanthanum, Lutetium, Neodymium, Praseodymium, Samarium, Terbium, Thulium, Yttrium, and Ytterbium. Samples from Don A. Campbell, Nevada collected on October 14, 2016.

Cryogenic Tm: YAG Laser in the Near Infrared

DTIC Science & Technology

2015-05-29

Applications Group. The focus of his work at Lincoln Laboratory has been solid-state lasers including microchip lasers , external-cavity diode lasers ...REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT) < Cryogenic Tm:YAG Laser in the Near Infrared* Tso Yee Fan...Senior Member, IEEE, Juan R. Ochoa, and Patricia A. Reed Abstract- Thulium laser operation on the 3H4 - 3H6 transition at 823 nm has been demonstrated

Efficient charge transfer and utilization of near-infrared solar spectrum by ytterbium and thulium codoped gadolinium molybdate (Gd2(MoO4)3:Yb/Tm) nanophosphor in hybrid solar cells.

PubMed

Sun, Weifu; Chen, Zihan; Zhang, Qin; Zhou, Junli; Li, Feng; Jin, Xiao; Li, Dongyu; Li, Qinghua

2016-11-09

In this work, thulium and ytterbium codoped gadolinium molybdate (Gd 2 (MoO 4 ) 3 :Yb/Tm) nanophosphors (NPs) have been synthesized, followed by being incorporated into a photo-catalytic titania (TiO 2 ) nanoparticle layer. In detail, morphology and phase identification of the prepared NPs are first characterized and then the up-conversion of the Gd 2 (MoO 4 ) 3 :Yb/Tm NPs is studied. Electron transfer dynamics after interfacing with bare or NP-doped electron donor TiO 2 and the corresponding photovoltaic performance of solar cells are explored. The results show that Gd 2 (MoO 4 ) 3 :Yb/Tm NPs excited at 976 nm exhibit intense blue (460-498 nm) and weak red (627-669 nm) emissions. The lifetime of electron transfer is shortened from 817 to 316 ps after incorporating NPs and correspondingly the electron transfer rate outstrips by 3 times that of the bare TiO 2 . Consequently, a notable power conversion efficiency of 4.15% is achieved as compared to 3.17% of pure TiO 2 /PTB7. This work demonstrates that the co-doping of robust rare earth ions with different unique functions can widen the harvesting range of the solar spectrum, boost electron transfer rate and eventually strengthen device performance, without complicated interfacial and structural engineering.

Exploring high power, extreme wavelength operating potential of rare-earth-doped silica fiber

NASA Astrophysics Data System (ADS)

Zhou, Pu; Li, Ruixian; Xiao, Hu; Huang, Long; Zhang, Hanwei; Leng, Jinyong; Chen, Zilun; Xu, Jiangmin; Wu, Jian; Wang, Xiong

2017-08-01

Ytterbium-doped fiber laser (YDFL) and Thulium doped fiber laser (TDFL) have been two kinds of the most widely studied fiber laser in recent years. Although both silica-based Ytterbium-doped fiber and Thulium doped fiber have wide emission spectrum band (more than 200 nm and 400 nm, respectively), the operation spectrum region of previously demonstrated high power YDFL and TDFL fall into 1060-1100 nm and 1900-2050nm. Power scaling of YDFL and TDFL operates at short-wavelength or long-wavelength band, especially for extreme wavelength operation, although is highly required in a large variety of application fields, is quite challenging due to small net gain and strong amplified spontaneous emission (ASE). In this paper, we will present study on extreme wavelength operation of high power YDFL and TDFL in our group. Comprehensive mathematical models are built to investigate the feasibility of high power operation and propose effective technical methods to achieve high power operation. We have achieved (1) Diodepumped 1150nm long wavelength YDFL with 120-watt level output power (2) Diode-pumped 1178nm long wavelength YDFL operates at high temperature with 30-watt level output power (3) Random laser pumped 2153nm long wavelength TDFL with 20-watt level output power (4) Diode-pumped 1018nm short wavelength YDFL with a record 2 kilowatt output power is achieved by using home-made fiber combiner.

Fiber-optic manipulation of urinary stone phantoms using holmium:YAG and thulium fiber lasers.

PubMed

Blackmon, Richard L; Case, Jason R; Trammell, Susan R; Irby, Pierce B; Fried, Nathaniel M

2013-02-01

Fiber-optic attraction of urinary stones during laser lithotripsy may be exploited to manipulate stone fragments inside the urinary tract without mechanical grasping tools, saving the urologist time and space in the ureteroscope working channel. We compare thulium fiber laser (TFL) high pulse rate/low pulse energy operation to conventional holmium:YAG low pulse rate/high pulse energy operation for fiber-optic suctioning of plaster-of-paris (PoP) stone phantoms. A TFL (wavelength of 1908 nm, pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rate of 10 to 350 Hz) and a holmium laser (wavelength of 2120 nm, pulse energy of 35 to 360 mJ, pulse duration of 300 μs, and pulse rate of 20 Hz) were tested using 270-μm-core optical fibers. A peak drag speed of ~2.5 mm/s was measured for both TFL (35 mJ and 150 to 250 Hz) and holmium laser (210 mJ and 20 Hz). Particle image velocimetry and thermal imaging were used to track water flow for all parameters. Fiber-optic suctioning of urinary stone phantoms is feasible. TFL operation at high pulse rates/low pulse energies is preferable to holmium operation at low pulse rates/high pulse energies for rapid and smooth stone pulling. With further development, this novel technique may be useful for manipulating stone fragments in the urinary tract.

Photoselective laser ablation of the prostate: a review of the current 2015 tissue ablation options.

PubMed

Tholomier, Côme; Valdivieso, Roger; Hueber, Pierre-Alain; Zorn, Kevin C

2015-10-01

Transurethral resection of the prostate (TURP) is still considered the gold standard to treat benign prostatic hyperplasia (BPH). However, photoselective vaporization of the prostate (PVP) has gained widespread acceptance as an alternative option requiring preoperative patient selection. Four laser systems are currently in use: holmium, thulium, diode and GreenLight. The goal of this article is to review the physics and the basics behind laser prostatectomies, as well as to present the most current literature concerning the results, advantages, disadvantages and international recommendations for each vaporization procedure. Holmium laser ablation of the prostate (HoLAP) and GreenLight photoselective vaporization of the prostate are an alternative to TURP for small to medium-sized prostates, providing equivalent efficacy and safety. GreenLight is also safe and effective in large-sized prostates and especially beneficial in anti-coagulated individuals compared to TURP. Thulium vaporization of the prostate (ThuVAP) and diode vaporization both require additional randomized trials and long term studies before conclusion is made, despite promising initial results. Diode vaporization provides the best hemostasis overall, but at the cost of increased complication and re-treatment rate, and thus is not recommended except in severely anti-coagulated patients. Laser vaporization is a safe and effective alternative to TURP in the treatment of benign prostatic hyperplasia (BPH) for carefully selected patients. However, further research is still needed to assess the durability of each technology.

Randomized, Split-Face/Décolleté Comparative Trial of Procedure Enhancement System for Fractional non-Ablative Laser Resurfacing Treatment.

PubMed

Robinson, Deanne Mraz; Frulla, Ashton P

2017-07-01

INTRODUCTION: A topical proprietary procedural enhancement system (PES) containing a combination of active ingredients including a tripeptide and hexapeptide (TriHex Technology™, Alastin Procedure Enhancement Invasive System, ALASTIN Skincare™, Inc., Carlsbad, CA) has been used successfully to aid in healing and improve symptomatology following resurfacing procedures.

METHODS: PES (Gentle Cleanser, Regenerating Skin Nectar with TriHex Technology™, Ultra Nourishing Moisturizer with TriHex Technology™, Soothe + Protect Recovery Balm, Broad Spectrum 30+ Sunscreen) was compared to a basic regimen (Aquaphor™, Cerave™ cleanser, Vanicream™, Alastin Broad Spectrum 30+ Sunscreen) in a split face/ décolleté trial following fractional non-ablative thulium-doped resurfacing treatment to the face or décolleté. The skin was pre-conditioned and treated during and after the procedure using the two regimens.

RESULTS: A blinded investigator rated the PES statistically superior to the basic regimen on healing post-laser treatment on day 4 based on lentigines, texture, and Global Skin Quality. Subjects also reported 'better looking and feeling' skin on the PES side.

CONCLUSION: PES appears to improve healing post-non ablative thulium-doped resurfacing treatment to the face/décolleté in comparison with standard of care.

J Drugs Dermatol. 2017;16(7):707-710.

Rapid vaporization of kidney stones, ex vivo, using a Thulium fiber laser at pulse rates up to 500 Hz with a stone basket

NASA Astrophysics Data System (ADS)

Hardy, Luke A.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

2014-03-01

The Holmium:YAG laser (λ = 2120 nm) is currently the preferred laser for fragmenting kidney stones in the clinic. However, this laser has some limitations, including operation at low pulse rates and a multimode spatial beam profile which prohibits its use with smaller, more flexible optical fibers. Our laboratory is studying the Thulium fiber laser (λ = 1908 nm) as an alternative lithotripter. The TFL has several advantages, including lower stone ablation thresholds, use with smaller and more flexible fibers, and operation at arbitrary pulse lengths and pulse rates. Previous studies have reported increased stone ablation rates with TFL operation at higher pulse rates, however, stone retropulsion remains an obstacle to even more efficient stone ablation. This study explores TFL operation at high pulse rates in combination with a stone stabilization device (e.g. stone basket) for improved efficiency. A TFL beam with pulse energy of 35 mJ, pulse duration of 500-μs, and pulse rates of 10-500 Hz was coupled into 100-μm-core, low-OH, silica fibers, in contact mode with uric acid and calcium oxalate monohydrate stones, ex vivo. TFL operation at 500 Hz produced UA and COM stone ablation rates up to 5.0 mg/s and 1.3 mg/s, respectively. High TFL pulse rates produced increased stone ablation rates sufficient for use in the clinic.

Novel Optical Methods for Identification, Imaging, and Preservation of the Cavernous Nerves Responsible for Penile Erections during Prostate Cancer Surgery

DTIC Science & Technology

2009-03-01

wavelength, pulse energy, and pulse rate) to produce strongest and most rapid erectile response as measured by intracavernosal pressure in the penis ...PC Fiber Rod Housing Optics 5-mm-ID Port Probe Handle Probe Stem Enlarged View of Probe Tip Oscilloscope FunctionGenerator Thulium Fiber Laser Shutter...rapid erectile response as measured by intracavernosal pressure (ICP) in the penis . ICP values were increased from an initial range of 30-40 mmHg

An in vitro Corneal Model with a Laser Damage Threshold at 2 Micrometers That is Similar to That in the Rabbit

DTIC Science & Technology

2007-11-01

Proceedings 3. DATES COVERED (From - To) June 2007- November 2007 4. TITLE AND SUBTITLE An In Vitro Corneal Model with a Laser Damage Threshold at 2...2-µm wavelength output of a thulium fiber laser with 4 mm beam diameter for 0.25 seconds in a thermally controlled environment and then assayed for...data in the literature. 15. SUBJECT TERMS corneal organotypic culture, laser , threshold, thermography, Probit 16. SECURITY CLASSIFICATION OF

Diode-Pumped, 2-Micron, Q-Switched Thulium: Y3Al5O12 (Tm:Yag) Microchip Laser

DTIC Science & Technology

2011-05-01

switch with a chromium -doped zinc selenide crystal acting as a saturable absorber passive Q-switch. Finally, we will propose possible future...literature by Heine and Huber [4] and others, while passive Q-switching of 2 μm lasers by a chromium -doped zinc selenide has been demonstrated by Tsai and...these objectives for each component of the laser system. In Chapter 4 a design is presented for replacing our acousto-optic Q-switch with a chromium

TmDOTA -: A Sensitive Probe for MR Thermometry in Vivo

NASA Astrophysics Data System (ADS)

Zuo, Chun S.; Mahmood, Ashfaq; Sherry, A. Dean

2001-07-01

The lanthanide complex, thulium 1,4,7,10-tetraazacyclodo- decane-1,4,7,10-tetraacetic acid (TmDOTA-), has been investigated as an agent for MR thermometry in vivo. The chemical shifts of the TmDOTA- protons were highly sensitive to temperature at a clinically relevant field strength, yet insensitive to pH and the presence of Ca2+. Given the excellent stability of lanthanide-DOTA complexes and high thermal sensitivity, TmDOTA- is expected to be a good candidate for MR thermometry in vivo.

New World Vistas: Air and Space Power for the 21st Century. Directed Energy Volume

DTIC Science & Technology

1995-01-01

single mode diode pumped Thulium doped glass fiber laser. Full scale 5-10 watt devices have operated in the laboratory at overall efficiencies of 10...operating in the 900-950 nm range together with the development of ytterbium (Yb) doped laser crystals. The Yb ion generates roughly one third as much...mirror in the high power oscillator resonator . Since a potentially large amount of power is dissipated in the nonlinear medium, careful attention to

Quasi four-level Tm:LuAG laser

NASA Technical Reports Server (NTRS)

Jani, Mahendra G. (Inventor); Barnes, Norman P. (Inventor); Hutcheson, Ralph L. (Inventor); Rodriguez, Waldo J. (Inventor)

1997-01-01

A quasi four-level solid-state laser is provided. A laser crystal is disposed in a laser cavity. The laser crystal has a LuAG-based host material doped to a final concentration between about 2% and about 7% thulium (Tm) ions. For the more heavily doped final concentrations, the LuAG-based host material is a LuAG seed crystal doped with a small concentration of Tm ions. Laser diode arrays are disposed transversely to the laser crystal for energizing the Tm ions.

Fiber-optic manipulation of urinary stone phantoms using holmium:YAG and thulium fiber lasers

NASA Astrophysics Data System (ADS)

Blackmon, Richard L.; Case, Jason R.; Trammell, Susan R.; Irby, Pierce B.; Fried, Nathaniel M.

2013-02-01

Fiber-optic attraction of urinary stones during laser lithotripsy may be exploited to manipulate stone fragments inside the urinary tract without mechanical grasping tools, saving the urologist time and space in the ureteroscope working channel. We compare thulium fiber laser (TFL) high pulse rate/low pulse energy operation to conventional holmium:YAG low pulse rate/high pulse energy operation for fiber-optic suctioning of plaster-of-paris (PoP) stone phantoms. A TFL (wavelength of 1908 nm, pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rate of 10 to 350 Hz) and a holmium laser (wavelength of 2120 nm, pulse energy of 35 to 360 mJ, pulse duration of 300 μs, and pulse rate of 20 Hz) were tested using 270-μm-core optical fibers. A peak drag speed of ˜2.5 mm/s was measured for both TFL (35 mJ and 150 to 250 Hz) and holmium laser (210 mJ and 20 Hz). Particle image velocimetry and thermal imaging were used to track water flow for all parameters. Fiber-optic suctioning of urinary stone phantoms is feasible. TFL operation at high pulse rates/low pulse energies is preferable to holmium operation at low pulse rates/high pulse energies for rapid and smooth stone pulling. With further development, this novel technique may be useful for manipulating stone fragments in the urinary tract.

Thulium fiber laser lithotripsy using small spherical distal fiber tips

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hardy, Luke A.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

2016-02-01

This study tests a 100-μm-core fiber with 300-μm-diameter ball tip during Thulium fiber laser (TFL) lithotripsy. The TFL was operated at 1908 nm wavelength with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times measured, and ablation rates calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to observe ball tip degradation and determine number of procedures completed before need to replace fiber. Saline irrigation rates and ureteroscope deflection were measured with and without TFL fiber present. There was no statistical difference (P > 0.05) between stone ablation rates for single-use ball tip fiber (1.3 +/- 0.4 mg/s) (n=10), multiple-use ball tip fiber (1.3 +/- 0.5 mg/s) (n=44), and conventional single-use bare tip fibers (1.3 +/- 0.2 mg/s) (n=10). Ball tip durability varied widely, but fibers averaged > 4 stone procedures before decline in stone ablation rates due to mechanical damage at front surface of ball tip. The small fiber diameter did not impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and the ureter without risk of scope damage or tissue perforation, and without compromising stone ablation efficiency during TFL ablation of kidney stones.

Nonlinear pulse compression stage delivering 43-W few-cycle pulses with GW peak-power at 2-μm wavelength

NASA Astrophysics Data System (ADS)

Gebhardt, Martin; Gaida, Christian; Heuermann, T.; Stutzki, F.; Jauregui, C.; Antonio-Lopez, J.; Schüuzgen, A.; Amezcua-Correa, R.; Tünnermann, A.; Limpert, J.

2018-02-01

In this contribution we demonstrate the nonlinear pulse compression of an ultrafast thulium-doped fiber laser down to 14 fs FWHM duration (sub-3 optical cycles) at a record average power of 43 W and 34.5 μJ pulse energy. To the best of our knowledge, we present the highest average power few-cycle laser source at 2 μm wavelength. This performance level in combination with GW-class peak power makes our laser source extremely interesting for driving high-harmonic generation or for generating mid-infrared frequency combs via intra-pulse frequency down-conversion at an unprecedented average power. The experiments were enabled by an ultrafast thulium-doped fiber laser delivering 110 fs pulses at high repetition rates, and an argon gas-filled antiresonant hollow-core fiber (ARHCF) with excellent transmission and weak anomalous dispersion, leading to the self-compression of the pulses. We have shown that ARHCFs are well-suited for nonlinear pulse compression around 2 μm wavelength and that this concept features excellent power handling capabilities. Based on this result, we discuss the next steps for energy and average power scaling including upscaling the fiber dimensions in order to fully exploit the capabilities of our laser system, which can deliver several GW of peak power. This way, a 100 W-class laser source with mJ-level few-cycle pulses at 2 μm wavelength is feasible in the near future.

Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy.

PubMed

Hutchens, Thomas C; Gonzalez, David A; Irby, Pierce B; Fried, Nathaniel M

2017-01-01

The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A “fiber muzzle brake” was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 ?? ? s , and 300 Hz using a 100 - ? m -core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560 - ? m -outer-diameter, 360 - ? m -inner-diameter tube with a 275 - ? m -diameter through hole located 250 ?? ? m from the distal end. The fiber tip was recessed a distance of 500 ?? ? m . Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40 ± 4 ?? mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 ± 4 ?? s

Investigations of initial airtightness after non-anatomic resection of lung parenchyma using a thulium-doped laser with different optical fibres.

PubMed

Kirschbaum, Andreas; Höchsmann, N; Steinfeldt, T; Seyfer, P; Pehl, A; Bartsch, D K; Palade, E

2016-08-01

Lung metastases in healthy patients should be removed non-anatomically whenever possible. This can be done with a laser. Lung parenchyma can be cut very well, because of its high energy absorption at a wavelength of 1940 nm. A coagulation layer is created on the resected surface. It is not clear, whether this surface also needs to be sutured to ensure that it remains airtight even at higher ventilation pressures. It would be helpful, if suturing could be avoided, because the lung can become too puckered, especially with multiple resections, resulting in considerable restriction. We carried out our experiments on isolated and ventilated paracardiac lung lobes of pigs. Non-anatomic resection was carried out reproducibly using three different thulium laser fibres (230, 365 and 600 μm) at two different laser power levels (10 W, 30 W) and three different resection depths (0.5, 1.0 and 2.0 cm). Initial airtightness was investigated while ventilating at normal frequency. We also investigated the bursting pressures of the resected areas by increasing the inspiratory pressure. When 230- and 365-μm fibres were used with a power of 10 W, 70 % of samples were initially airtight up to a resection depth of 1 cm. This rate fell at depths of up to 2 cm. All resected surfaces remained airtight during ventilation when 600-μm fibres were used at both laser power levels (10 and 30 W). The bursting pressures achieved with 600-μm fibres were higher than with the other fibres used: 0.5 cm, 41.6 ± 3.2 mbar; 1 cm, 38.2 ± 2.5 mbar; 2 cm, 33.7 ± 4.8 mbar. As laser power and thickness of laser fibre increased, so the coagulation zone became thicker. With a 600-μm fibre, it measured 145.0 ± 8.2 μm with 10 W power and 315.5 ± 6.4 μm with 30 W power. Closure with sutures after non-anatomic resection of lung parenchyma is not necessary when a thulium laser is used provided a 600-μm fibre and adequate laser power (30 W) are employed. At deeper resection levels, the risk of cutting small segmental bronchi is considerably increased. They must always be closed with sutures.

Nonablative 1927 nm fractional resurfacing for the treatment of facial photopigmentation.

PubMed

Brauer, Jeremy A; McDaniel, David H; Bloom, Bradley S; Reddy, Kavitha K; Bernstein, Leonard J; Geronemus, Roy G

2014-11-01

Long-term exposure to sunlight, including ultraviolet A and B, produces signs associated with photoaging and photodamage, including laxity and discoloration of the skin. Initial laser treatment for dyspigmentation included the use of ablative lasers, followed by Q-switched lasers and more recently fractional lasers. We investigated the safety and efficacy of a fractionated 1927nm non-ablative thulium laser for the treatment of photo-induced pigmentation. Prospective multi-center study of subjects with clinically identifiable photopigmentation. The study protocol was approved by BioMed Institutional Review Board (San Diego, CA). Subjects received two treatments with a non-ablative 1927nm fractionated thulium laser (Fraxel Dual 1550/1927 Laser System, Solta, Hayward CA), energy level of 10mJ, coverage of 40% and 4-6 passes. Subject pain, erythema and edema were recorded immediately after treatment. Two dimensional photography was obtained before each treatment and at one and three month follow up visits. Independent blinded physician assessment was performed evaluating overall improvement in appearance as well as pigment specific improvement. Forty men and women, ages 30 to 80 years, Fitzpatrick skin types I-IV, with photo-induced facial pigmentation were enrolled and treated, and 39 completed the three month follow up visit. Mean pain sensation for subjects during laser treatments was reported to be 4.3 on a 10-point scale. Mean scores for erythema, edema, and skin roughness throughout all treatments indicated moderate erythema, mild edema and mild skin roughness. Assessment of overall improvement was graded as moderate to very significant in 82% of subjects at one month and in 69% of subjects at three months after the second treatment. Assessment of lentigines and ephelides demonstrated moderate to very significant improvement in approximately 68% of subjects at the one month and in 51% of subjects at three months after the second treatment. Independent blinded physician assessment of randomized photography also demonstrated a durable response at three month follow up visit. Treatment was well tolerated and no serious adverse events related to treatment were observed or reported. Study limitations included a limited number of male subjects, lack of Fitzpatrick skin types V and VI, and decrease in improvement at 3 months post-treatment. Two treatments with a 1927nm non-ablative fractionated thulium laser produced moderate to marked improvement in overall appearance and pigmentation with high patient satisfaction. The response to treatment was maintained at one and three months follow up.

Photodegradation of near-infrared-pumped Tm(3+)-doped ZBLAN fiber upconversion lasers.

PubMed

Booth, I J; Archambault, J L; Ventrudo, B F

1996-03-01

Photodegradation has been observed in Tm(3+)-doped ZBLAN fiber lasers pumped with laser diodes at 1135 nm. After upconversion lasing at 482 nm, the fiber develops color centers that absorb strongly at wavelengths below ~650 nm, affecting further upconversion lasing. The rate of damage formation is strongly dependent on the pump power level and on the thulium concentration. The color centers are bleached by intense blue light but recover with thermal excitation and can be removed by thermal annealing at temperature near 100 degrees C.

152 W average power Tm-doped fiber CPA system.

PubMed

Stutzki, Fabian; Gaida, Christian; Gebhardt, Martin; Jansen, Florian; Wienke, Andreas; Zeitner, Uwe; Fuchs, Frank; Jauregui, Cesar; Wandt, Dieter; Kracht, Dietmar; Limpert, Jens; Tünnermann, Andreas

2014-08-15

A high-power thulium (Tm)-doped fiber chirped-pulse amplification system emitting a record compressed average output power of 152 W and 4 MW peak power is demonstrated. This result is enabled by utilizing Tm-doped photonic crystal fibers with mode-field diameters of 35 μm, which mitigate detrimental nonlinearities, exhibit slope efficiencies of more than 50%, and allow for reaching a pump-power-limited average output power of 241 W. The high-compression efficiency has been achieved by using multilayer dielectric gratings with diffraction efficiencies higher than 98%.

Modeled Neutron Induced Nuclear Reaction Cross Sections for Radiochemsitry in the region of Thulium, Lutetium, and Tantalum I. Results of Built in Spherical Symmetry in a Deformed Region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffman, R. D.

2013-09-06

We have developed a set of modeled nuclear reaction cross sections for use in radiochemical diagnostics. Systematics for the input parameters required by the Hauser-Feshbach statistical model were developed and used to calculate neutron induced nuclear reaction cross sections for targets ranging from Terbium (Z = 65) to Rhenium (Z = 75). Of particular interest are the cross sections on Tm, Lu, and Ta including reactions on isomeric targets.

99 W mid-IR operation of a ZGP OPO at 25% duty cycle.

PubMed

Hemming, Alexander; Richards, Jim; Davidson, Alan; Carmody, Neil; Bennetts, Shayne; Simakov, Nikita; Haub, John

2013-04-22

We have demonstrated the highest reported output power from a mid-IR ZGP OPO. The laser is a cascaded hybrid system consisting of a thulium fibre laser, Ho:YAG solid state laser and a Zinc Germanium Phosphide parametric oscillator. The system produces 27 W of output power in the 3-5 μm wavelength range with an M(2) = 4.0 when operating in a repetitively q-switched mode, and a modulated peak output power of 99 W at a reduced duty cycle of 25%.

Investigation on the potential of thulium-fibre-laser irradiation for in-stent tissue ablation (Conference Presentation)

NASA Astrophysics Data System (ADS)

Sroka, Ronald; Frank, Johannes; Reichenberger, Frank; Behr, J.; Gesierich, Wolfgang

2017-04-01

Granulation and tumor regrowth in the area of bronchi stent implants may result in restenosis. It had been shown that by means of Thulium-Fibre-Laser (TFL) a controlled ablation and reduction of the tissue within the stent could be performed. When using Nd:YAG irradiation there is risk for explosive flames, burns of fibre and stent, ruptures of stent meshes as well as perforation of stent and cover. Therefore it was the aim to investigate the safety margin when using TFL. Four different types of clinical used stents (with/without cover) were fixed to pig trachea tissue. Irradiation was performed by fibre assisted TFL-1940nm-laser irradiation while laser power, light application duration and distance, as well as oxygen percentage and contamination were varied. In case of Nitinol-stents rupture were observed at power levels >=7W or distances of <5mm, oxygen conc. of 40% result in increased flame appearance. Polyurethan-covers were ruptured at each variable, flame appeared at 5W. Silicon-stents were destroyed at power levels of about 5W and distances of <5mm and additionally 30%-oxygen or contamination either by blood or soot result in increased appearance of burns and flames. Based upon these observations in clinical TFL-irradiation the distance should >=5 mm and the power level should be <=6W. Furthermore the oxygen conc. should not exceed 30% and short term continuous irradiation of less than 15s exposition should be considered. In case of Silicon-stents light application on contaminated area should be avoided.

Scanning electron microscopy of real and artificial kidney stones before and after Thulium fiber laser ablation in air and water

NASA Astrophysics Data System (ADS)

Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

2018-02-01

We investigated proposed mechanisms of laser lithotripsy, specifically for the novel, experimental Thulium fiber laser (TFL). Previous lithotripsy studies with the conventional Holmium:YAG laser noted a primary photothermal mechanism (vaporization). Our hypothesis is that an additional mechanical effect (fragmentation) occurs due to vaporization of water in stone material from high absorption of energy, called micro-explosions. The TFL irradiated calcium oxalate monohydrate (COM) and uric acid (UA) stones, as well as artificial stones (Ultracal30 and BegoStone), in air and water environments. TFL energy was varied to determine the relative effect on the ablation mechanism. Scanning electron microscopy (SEM) was used to study qualitative and characteristic changes in surface topography with correlation to presumed ablation mechanisms. Laser irradiation of stones in air produced charring and melting of the stone surface consistent with a photothermal effect and minimal fragmentation, suggesting no mechanical effect from micro-explosions. For COM stones ablated in water, there was prominent fragmentation in addition to recognized photothermal effects, supporting dual mechanisms during TFL lithotripsy. For UA stones, there were minimal photothermal effects, and dominant effects were mechanical. By increasing TFL pulse energy, a greater mechanical effect was demonstrated for both stone types. For artificial stones, there was no significant evidence of mechanical effects. TFL laser lithotripsy relies on two prominent mechanisms for stone ablation, photothermal and mechanical. Water is necessary for the mechanical effect which can be augmented by increasing pulse energy. Artificial stones may not provide a predictive model for mechanical effects during laser lithotripsy.

Fragmentation and dusting of large kidney stones using compact, air-cooled, high peak power, 1940-nm, Thulium fiber laser

NASA Astrophysics Data System (ADS)

Hardy, Luke A.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2018-02-01

Previous Thulium fiber laser lithotripsy (TFL) studies were limited to a peak power of 70 W (35 mJ / 500 μs), requiring operation in dusting mode with low pulse energy (35 mJ) and high pulse rate (300 Hz). In this study, a novel, compact, air-cooled, TFL capable of operating at up to 500 W peak power, 50 W average power, and 2000 Hz, was tested. The 1940-nm TFL was used with pulse duration (500 μs), average power (10 W), and fiber (270- μm-core) fixed, while pulse energy and pulse rate were changed. A total of 23 large uric acid (UA) stones and 16 large calcium oxalate monohydrate (COM) stones were each separated into 3 modes (Group 1-"Dusting"- 33mJ/300Hz; Group 2-"Fragmentation"-200mJ/50Hz; Group 3-"Dual mode"-Fragmentation then Dusting). The fiber was held manually in contact with stone on a 2-mm-mesh sieve submerged in a flowing saline bath. UA ablation rates were 2.3+/-0.8, 2.3+/-0.2, and 4.4+/-0.8 mg/s and COM ablation rates were 0.4+/-0.1, 1.0+/-0.1, and 0.9+/-0.4 mg/s, for Groups 1, 2, and 3. Dual mode provided 2x higher UA ablation rates than other modes. COM ablation threshold is 3x higher than UA, so dusting provided lower COM ablation rates than other modes. Future studies will explore higher average laser power than 10 W for rapid TFL ablation of large stones.

Etching of enamel for direct bonding with a thulium fiber laser

NASA Astrophysics Data System (ADS)

Kabaş Sarp, Ayşe S.; Gülsoy, Murat

2011-03-01

Background: Laser etching of enamel for direct bonding can decrease the risk of surface enamel loss and demineralization which are the adverse effects of acid etching technique. However, in excess of +5.5°C can cause irreversible pulpal responses. In this study, a 1940- nm Thulium Fiber Laser in CW mode was used for laser etching. Aim: Determination of the suitable Laser parameters of enamel surface etching for direct bonding of ceramic brackets and keeping that intrapulpal temperature changes below the threshold value. Material and Method: Polycrystalline ceramic orthodontic brackets were bonded on bovine teeth by using 2 different kinds of etching techniques: Acid and Laser Etching. In addition to these 3 etched groups, there was also a group which was bonded without etching. Brackets were debonded with a material testing machine. Breaking time and the load at the breaking point were measured. Intrapulpal temperature changes were recorded by a K-type Thermocouple. For all laser groups, intrapulpal temperature rise was below the threshold value of 5.5°C. Results and Conclusion: Acid-etched group ( 11.73 MPa) significantly required more debonding force than 3- second- irradiated ( 5.03 MPa) and non-etched groups ( 3.4 MPa) but the results of acid etched group and 4- second- irradiated group (7.5 MPa) showed no significant difference. Moreover, 4- second irradiated group was over the minimum acceptable value for clinical use. Also, 3- second lasing caused a significant reduction in time according to acid-etch group. As a result, 1940- nm laser irradiation is a promising method for laser etching.

Recent development on high-power tandem-pumped fiber laser

NASA Astrophysics Data System (ADS)

Zhou, Pu; Xiao, Hu; Leng, Jinyong; Zhang, Hanwei; Xu, Jiangmin; Wu, Jian

2016-11-01

High power fiber laser is attracting more and more attention due to its advantage in excellent beam quality, high electricto- optical conversion efficiency and compact system configuration. Power scaling of fiber laser is challenged by the brightness of pump source, nonlinear effect, modal instability and so on. Pumping active fiber by using high-brightness fiber laser instead of common laser diode may be the solution for the brightness limitation. In this paper, we will present the recent development of various kinds of high power fiber laser based on tandem pumping scheme. According to the absorption property of Ytterbium-doped fiber, Thulium-doped fiber and Holmium-doped fiber, we have theoretically studied the fiber lasers that operate at 1018 nm, 1178 nm and 1150 nm, respectively in detail. Consequently, according to the numerical results we have optimized the fiber laser system design, and we have achieved (1) 500 watt level 1018nm Ytterbium-doped fiber laser (2) 100 watt level 1150 nm fiber laser and 100 watt level random fiber laser (3) 30 watt 1178 nm Ytterbium-doped fiber laser, 200 watt-level random fiber laser. All of the above-mentioned are the record power for the corresponded type of fiber laser to the best of our knowledge. By using the high-brightness fiber laser operate at 1018 nm, 1178 nm and 1150 nm that we have developed, we have achieved the following high power fiber laser (1) 3.5 kW 1090 nm Ytterbium-doped fiber amplifier (2) 100 watt level Thulium-doped fiber laser and (3) 50 watt level Holmium -doped fiber laser.

Thulium fiber laser lithotripsy using a muzzle brake fiber tip

NASA Astrophysics Data System (ADS)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-02-01

The Thulium fiber laser (TFL) is being explored as an alternative to Holmium:YAG laser for lithotripsy. TFL beam profile allows coupling of higher power into smaller fibers than multimode Holmium laser beam, without proximal fiber tip degradation. A smaller fiber provides more space in ureteroscope working channel for increased saline irrigation and allows maximum ureteroscope flexion. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback, but increased retropulsion. In this study, a "fiber muzzle brake" was tested for reducing fiber burnback and stone retropulsion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-OD, 360-μm-ID tube with 275-μm thru hole located 250-μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed, ex vivo. Small stones with a mass of 40 +/- 4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25 +/- 4 s (n=10), without distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers. The muzzle brake fiber tip provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

Hollow steel tips for reducing distal fiber burn-back during thulium fiber laser lithotripsy.

PubMed

Hutchens, Thomas C; Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

2013-07-01

The use of thulium fiber laser (TFL) as a potential alternative laser lithotripter to the clinical holmium:YAG laser is being studied. The TFL's Gaussian spatial beam profile provides efficient coupling of higher laser power into smaller core fibers without proximal fiber tip degradation. Smaller fiber diameters are more desirable, because they free up space in the single working channel of the ureteroscope for increased saline irrigation rates and allow maximum ureteroscope deflection. However, distal fiber tip degradation and "burn-back" increase as fiber diameter decreases due to both excessive temperatures and mechanical stress experienced during stone ablation. To eliminate fiber tip burn-back, the distal tip of a 150-μm core silica fiber was glued inside 1-cm-long steel tubing with fiber tip recessed 100, 250, 500, 1000, or 2000 μm inside the steel tubing to create the hollow-tip fiber. TFL pulse energy of 34 mJ with 500-μs pulse duration and 150-Hz pulse rate was delivered through the hollow-tip fibers in contact with human calcium oxalate monohydrate urinary stones during ex vivo studies. Significant fiber tip burn-back and degradation was observed for bare 150-μm core-diameter fibers. However, hollow steel tip fibers experienced minimal fiber burn-back without compromising stone ablation rates. A simple, robust, compact, and inexpensive hollow fiber tip design was characterized for minimizing distal fiber burn-back during the TFL lithotripsy. Although an increase in stone retropulsion was observed, potential integration of the hollow fiber tip into a stone basket may provide rapid stone vaporization, while minimizing retropulsion.

Temporal model of an optically pumped co-doped solid state laser

NASA Technical Reports Server (NTRS)

Wangler, T. G.; Swetits, J. J.; Buoncristiani, A. M.

1993-01-01

Currently, research is being conducted on the optical properties of materials associated with the development of solid state lasers in the two micron region. In support of this effort, a mathematical model describing the energy transfer in a holmium laser sensitized with thulium is developed. In this paper, we establish some qualitative properties of the solution of the model, such as non-negativity, boundedness, and integrability. A local stability analysis is then performed from which conditions for asymptotic stability are attained. Finally, we report on our numerical analysis of the system and how it compares with experimental results.

Thulium fiber laser for the use in low-invasive endoscopic and robotic surgery of soft biological tissues

NASA Astrophysics Data System (ADS)

Michalska, M.; Brojek, W.; Rybak, Z.; Sznelewski, P.; Mamajek, M.; Gogler, S.; Swiderski, J.

2016-12-01

An all-fiber, diode-pumped, continuous-wave Tm3+-doped fiber laser operated at a wavelength of 1.94 μm was developed. 37.4 W of output power with a slope efficiency as high as 57% with respect to absorbed pump power at 790 nm was demonstrated. The laser output beam quality factor M2 was measured to be 1.2. The output beam was very stable with power fluctuations <1% measured over 1 hour. The laser system is to be implemented as a scalpel for surgery of soft biological tissues.

Improving Lifetime of Quasi-CW Laser Diode Arrays for Pumping 2-Micron Solid State Lasers

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Singh, Upendra N.; Kavaya, Michael J.

2007-01-01

Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data on the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

Improving Reliability of High Power Quasi-CW Laser Diode Arrays Operating in Long Pulse Mode

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Meadows, Byron L.; Barnes, Bruce W.; Lockard, George E.; Singh, Upendra N.; Kavaya, Michael J.; Baker, Nathaniel R.

2006-01-01

Operating high power laser diode arrays in long pulse regime of about 1 msec, which is required for pumping 2-micron thulium and holmium-based lasers, greatly limits their useful lifetime. This paper describes performance of laser diode arrays operating in long pulse mode and presents experimental data of the active region temperature and pulse-to-pulse thermal cycling that are the primary cause of their premature failure and rapid degradation. This paper will then offer a viable approach for determining the optimum design and operational parameters leading to the maximum attainable lifetime.

120-W 2-µm thulium:yttrium-aluminium-garnet vapoenucleation of the prostate: 12-month follow-up.

PubMed

Netsch, Christopher; Pohlmann, Laura; Herrmann, Thomas R W; Gross, Andreas J; Bach, Thorsten

2012-07-01

Study Type - Therapy (case series) Level of Evidence 4 What's known on the subject? and What does the study add? Thulium VapoEnucleation of the prostate (ThuVEP) has been introduced as a minimally invasive treatment modality of benign prostate obstruction (BPO). This study reports the largest series of patients with symptomatic BPO undergoing ThuVEP. Efficacy of this procedure was confirmed by prostate volume and PSA measurements at 12-month follow up, which have not been reported after ThuVEP so far. To evaluate the safety and efficacy of 120-W 2-µm thulium:yttrium-aluminium-garnet (YAG) vapoenucleation of the prostate (ThuVEP) for patients with symptomatic benign prostatic obstruction. In total, 207 consecutive patients undergoing ThuVEP at our institution were evaluated prospectively. ThuVEP was carried out using the 120-W 2-µm continuous-wave Tm:YAG laser. The enucleated tissue was then morcellated within the bladder. Patient demographic, perioperative and 12-month follow-up data were analysed. The complications were assessed. Mean preoperative prostate volume was 57.8 ± 31.5 mL. Total operation duration averaged 64.9 ± 29.9 min, and the enucleation time was 36.5 ± 20.1 min. The mean catheter time was 2.2 ± 0.6 days. Thirteen (6.28%) patients required a second-look operation in the immediate postoperative course (failed morcellation n= 1, clot retention n= 4, residual tissue at the apex of the prostate n= 8). Four patients needed blood transfusions (1.93%) postoperatively. In all, 147 (71%) patients were available for review at the 12-month follow-up mark. Quality of life (4.4 ± 1.3 vs 1.2 ± 1.1), international prostate symptom score (21.9 ± 7.2 vs 5.1 ± 4), maximum urinary flow rate (9.4 ± 3.8 vs 23.5 ± 10.9 mL/s), postvoiding residual urine (159.2 ± 153.2 vs 26.7 ± 38.3 mL), prostate-specific antigen (5.0 ± 5.2 vs 0.6 ± 0.5 ng/mL) and prostate volume (57.8 ± 31.5 vs 10.7 ± 4.4 mL) changed significantly (P= 0.000). Median prostate-specific antigen reduction and prostate volume reduction were 87% and 80% respectively at follow-up. Urethral stricture and bladder neck contracture developed in 1.45% and 1.93% respectively of the patients. 120-W ThuVEP is a safe and efficacious procedure for the treatment of symptomatic benign prostatic obstruction. The incidence of complications with ThuVEP was low. © 2011 BJU INTERNATIONAL.

Thulium-yttrium-aluminium-garnet (Tm:YAG) laser treatment of penile cancer: oncological results, functional outcomes, and quality of life.

PubMed

Musi, Gennaro; Russo, Andrea; Conti, Andrea; Mistretta, Francesco A; Di Trapani, Ettore; Luzzago, Stefano; Bianchi, Roberto; Renne, Giuseppe; Ramoni, Stefano; Ferro, Matteo; Matei, Deliu Victor; Cusini, Marco; Carmignani, Luca; de Cobelli, Ottavio

2018-02-01

To evaluate the oncological and functional outcomes of patients diagnosed with penile cancer undergoing conservative treatment through thulium-yttrium-aluminium-garnet (Tm:YAG) laser ablation. Twenty-six patients with a penile lesion underwent ablation with a RevoLix 200 W continuous-wave laser. The procedure was carried out with a pen-like laser hand piece, using a 360 μm laser fiber and 15-20 W of power. Median (IQR) follow-up time was 24 (15-30) months. Recurrence rate and post-operative sexual function were assessed. Median age at surgery was 61 years. Median (inter quartile range) size of the lesions was 15 [10-20] mm. Overall, 11 (47.8%) and 12 (52.2%) at the final pathology presented in situ and invasive squamous cell carcinoma (SCC), respectively. The final pathological stage was pTis, pT1a, pT2, and pT3 in 11 (47.8%), 7 (30.4%), 3 (13.0%), and 2 (8.7%) patients, respectively. Moreover, four (17.4%) patients had a recurrence of which three (13.0%) and one (4.3%) patients developed an invasive or in situ recurrence, respectively. After treatment 6 (26.1%) patients reported a conserved penile sensitivity, while 13 (56.5%) and 4 (17.4%) patients experienced a better or worse sensitivity after ablation, respectively. Post-treatment sexual activity was achieved within the first month after laser ablation in 82.6% of the patients. Early stage penile carcinomas can be effectively treated with an organ preservation strategy. Tm:YAG conservative laser treatment is easy, safe and offers good functional outcome, with a minor impact on patient's quality of life.

Thulium Laser Treatment of Upper Urinary Tract Carcinoma: A Multi-Institutional Analysis of Surgical and Oncological Outcomes.

PubMed

Musi, Gennaro; Mistretta, Francesco A; Marenghi, Carlo; Russo, Andrea; Catellani, Michele; Nazzani, Sebastiano; Conti, Andrea; Luzzago, Stefano; Ferro, Matteo; Matei, Deliu V; Carmignani, Luca; de Cobelli, Ottavio

2018-03-01

To evaluate the efficacy and safety of ureteroscopic thulium laser (TL) treatment of upper urinary tract carcinoma (UTUC). Forty-two consecutive patients underwent conservative TL treatment for UTUC at two referral institutions. All patients underwent preliminary biopsy and then laser vaporization. A 272 μm and 365 μm laser fibers were used with a flexible and semirigid scope, respectively. Ablation was carried out with a 10 to 20 W power. Mean age at surgery was 68 years (SD 10.7). Mean tumor size was 14.3 mm (range 2-30 mm). Preliminary biopsy revealed the presence of low-grade disease in 29 (69.1%) patients, high-grade disease in 4 (9.5%) and 1 carcinoma in situ 1 (2.4%), whereas it was not conclusive in 8 (19%) cases. Final stage was pTa and pTis in 41 (97.6%) and 1 (2.4%) patients, respectively. Thirty eight percent (16) experienced Clavien-Dindo grade I complication, 47.6% (20) grade II, and 2.4% (1) grade III. Five (12%) patients underwent a second-look procedure due to residual disease. Eight (19%) patients experienced clinical recurrence. The median estimated recurrence-free survival was 44 months (SE 3.68). Four patients (9.5%) underwent a nephroureterectomy. Final pathological stage was pTis, pT3 high grade, pTa low grade, and pT0. Median follow-up was 26.3 months (range 2-54 months), and no progression or upstaging of disease occurred. TL management of UTUC is a safe and efficacious conservative treatment. Our experience shows optimal vaporization and hemostatic control in the absence of major complications.

Understanding the tissue interaction of new treatment modalities in laparoscopic surgery in view of safe and effective application (Conference Presentation)

NASA Astrophysics Data System (ADS)

Grimbergen, Matthijs C. M.; Klaessens, John H.; van der Veen, Albert J.; Verdaasdonk, Rudolf M.

2016-03-01

During laparoscopic surgery, devices are require to either cut, ablate or coagulate tissue and veins with high precision and controlled lateral damage preferably in an one-for-all modality. The tissue interactions of 3 new treatment modalities were studied using special imaging techniques to obtain a better understanding the working mechanism in view of effective and safe application. The Plasmajet produces a high temperature ionized gas 'flame' directed to the tissue surface at the tip of a 4 mm diameter rigid hand piece. The Lumenis DUO CO2 laser enables endoscopic laser energy delivery through a 1 mm outer diameter flexible hollow waveguide. The 2 µm 'Thulium' laser is delivered by (standard) 400 µm diameter optical fiber. Thermal imaging and Schlieren techniques were used to assess the superficial ablative and coagulation effects these surgical instruments scanning at preset velocities and distances from the surface of biological tissues and phantoms . The CO2 was very effective in tissue ablation even at a distance up to 10 mm due to a very small diverging beam from the hollow waveguide. In contrast, the Thulium laser showed less ablation and increasing coagulation at larger distance to the tissue. The gas 'flame' of the Plasmajet spread the thermal energy over the surface for effective superficial ablation and coagulation. However, the pressure of the gas flow is substantial on the tissue surface creating turbulence and even indirect cooling. The specific ablation and coagulation effects of the three treatment modalities have to be appreciate and the effective and safe application will depend on the preference and skills of the surgeon

Evaluation of the learning curve for thulium laser enucleation of the prostate with the aid of a simulator tool but without tutoring: comparison of two surgeons with different levels of endoscopic experience.

PubMed

Saredi, Giovanni; Pirola, Giacomo Maria; Pacchetti, Andrea; Lovisolo, Jon Alexander; Borroni, Giacomo; Sembenini, Federico; Marconi, Alberto Mario

2015-06-09

The aim of this study was to determine the learning curve for thulium laser enucleation of the prostate (ThuLEP) for two surgeons with different levels of urological endoscopic experience. From June 2012 to August 2013, ThuLEP was performed on 100 patients in our institution. We present the results of a prospective evaluation during which we analyzed data related to the learning curves for two surgeons of different levels of experience. The prostatic adenoma volumes ranged from 30 to 130 mL (average 61.2 mL). Surgeons A and B performed 48 and 52 operations, respectively. Six months after surgery, all patients were evaluated with the International Prostate Symptom Score questionnaire, uroflowmetry, and prostate-specific antigen test. Introduced in 2010, ThuLEP consists of blunt enucleation of the prostatic apex and lobes using the sheath of the resectoscope. This maneuver allows clearer visualization of the enucleation plane and precise identification of the prostatic capsule. These conditions permit total resection of the prostatic adenoma and coagulation of small penetrating vessels, thereby reducing the laser emission time. Most of the complications in this series were encountered during morcellation, which in some cases was performed under poor vision because of venous bleeding due to surgical perforation of the capsule during enucleation. Based on this analysis, we concluded that it is feasible for laser-naive urologists with endoscopic experience to learn to perform ThuLEP without tutoring. Those statements still require further validation in larger multicentric study cohort by several surgeon. The main novelty during the learning process was the use of a simulator that faithfully reproduced all of the surgical steps in prostates of various shapes and volumes.

Thulium laser enucleation (ThuLEP) versus transurethral resection of the prostate in saline (TURis): A randomized prospective trial to compare intra and early postoperative outcomes.

PubMed

Bozzini, G; Seveso, M; Melegari, S; de Francesco, O; Buffi, N M; Guazzoni, G; Provenzano, M; Mandressi, A; Taverna, G

2017-06-01

To compare clinical intra and early postoperative outcomes between thulium laser transurethral enucleation of the prostate (ThuLEP) and transurethral bipolar resection of the prostate (TURis) for treating benign prostatic hyperplasia (BPH) in a prospective randomized trial. The study randomized 208 consecutive patients with BPH to ThuLEP (n=102) or TURis (n=106). For all patients were evaluated preoperatively with regards to blood loss, catheterization time, irrigation volume, hospital stay and operative time. At 3 months after surgery they were also evaluated by International Prostate Symptom Score (IPSS), maximum flow rate (Qmax), and postvoid residual urine volume (PVR). The patients in each study arm each showed no significant difference in preoperative parameters. Compared with TURIS, ThuLEP had same operative time (53.69±31.44 vs 61.66±18.70minutes, P=.123) but resulted in less hemoglobin decrease (0.45 vs 2.83g/dL, P=.005). ThuLEP also needed less catheterization time (1.3 vs 4.8 days, P=.011), irrigation volume (29.4 vs 69.2 L, P=.002), and hospital stay (1.7 vs 5.2 days, P=.016). During the 3 months of follow-up, the procedures did not demonstrate a significant difference in Qmax, IPSS, PVR, and QOLS. ThuLEP and TURis both relieve lower urinary tract symptoms equally, with high efficacy and safety. ThuLEP was statistically superior to TURis in blood loss, catheterization time, irrigation volume, and hospital stay. However, procedures did not differ significantly in Qmax, IPSS, PVR, and QOLS through 3 months of follow-up. Copyright © 2016 AEU. Publicado por Elsevier España, S.L.U. All rights reserved.

An integrated fiber and stone basket device for use in Thulium fiber laser lithotripsy

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hutchens, Thomas C.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

2014-03-01

The Thulium fiber laser (TFL) is being explored as an alternative laser lithotripter to the Holmium:YAG laser. The TFL's superior near-single mode beam profile enables higher power transmission through smaller fibers with reduced proximal fiber tip damage. Recent studies have also reported that attaching hollow steel tubing to the distal fiber tip decreases fiber degradation and burn-back without compromising stone ablation rates. However, significant stone retropulsion was observed, which increased with pulse rate. In this study, the hollow steel tip fiber design was integrated with a stone basket to minimize stone retropulsion during ablation. A device was constructed consisting of a 100-μm-core, 140-μm-OD silica fiber outfitted with 5-mm-long stainless steel tubing at the distal tip, and integrated with a 1.3-Fr (0.433-mm-OD) disposable nitinol wire basket, to form an overall 1.9-Fr (0.633-mm- OD) integrated device. This compact design may provide several potential advantages including increased flexibility, higher saline irrigation rates through the ureteroscope working channel, and reduced fiber tip degradation compared to separate fiber and stone basket manipulation. TFL pulse energy of 31.5 mJ with 500 μs pulse duration and pulse rate of 500 Hz was delivered through the integrated fiber/basket device in contact with human uric acid stones, ex vivo. TFL stone ablation rates measured 1.5 +/- 0.2 mg/s, comparable to 1.7 +/- 0.3 mg/s (P > 0.05) using standard bare fiber tips separately with a stone basket. With further development, this device may be useful for minimizing stone retropulsion, thus enabling more efficient TFL lithotripsy at higher pulse rates.

Sexual outcome of patients undergoing thulium laser enucleation of the prostate for benign prostatic hyperplasia.

PubMed

Carmignani, Luca; Bozzini, Giorgio; Macchi, Alberto; Maruccia, Serena; Picozzi, Stefano; Casellato, Stefano

2015-01-01

Treatment of patients with lower urinary tract symptoms (LUTS) secondary to benign prostatic hyperplasia (BPH) may affect the quality of sexual function and ejaculation. The effect of new surgical procedures, which are currently available to treat BPH, on erection and ejaculation, has been poorly studied. This study aimed to assess the effect of thulium laser enucleation of the prostate (ThuLEP) on sexual function and retrograde ejaculation in patients with LUTS secondary to BPH. We performed a prospective study in 110 consecutive patients who had undergone ThuLEP to analyze changes in sexual function and urinary symptoms. To evaluate changes in erection and ejaculation, and the effect of urinary symptoms on the quality of life (QoL), five validated questionnaires were used: the ICIQ-MLUTSsex, MSHQ-EjD, International Index of Erectile Function 5, International Prognostic Scoring System (IPSS) questionnaire, and QoL index of the intraclass correlation coefficients. Patients also underwent IPSS and flowmetry to assess the outcome of flow. Patients were evaluated before surgery and 3-6 months after ThuLEP, whereas those with previous abdominal surgery were excluded. The patients' mean age was 67.83 years. Postoperative urinary symptoms improved after surgery. No significant differences in erectile function before and after surgery were observed. As compared with other techniques described in the literature, the percentage of patients with conserved ejaculation increased by 52.7% after ThuLEP. ThuLEP positively affects urinary symptoms and their effect on the QoL of patients as assessed by questionnaire scores. While endoscopic management of BPH (e.g. transurethral resection of the prostate) causes retrograde ejaculation in most patients, those who undergo ThuLEP have conserved ejaculation and erectile function.

Towards sub-100 fs multi-GW pulses directly emitted from a Thulium-doped fiber CPA system

NASA Astrophysics Data System (ADS)

Gaida, C.; Gebhardt, M.; Stutzki, F.; Jauregui, C.; Limpert, J.; Tünnermann, A.

2017-02-01

Experimental demonstrations of Tm-doped fiber amplifiers (typically in CW- or narrow-band pulsed operation) span a wavelength range going from about 1700 nm to well beyond 2000 nm. Thus, it should be possible to obtain a bandwidth of more than 100 nm, which would enable sub-100 fs pulse duration in an efficient, linear amplification scheme. In fact, this would allow the emission of pulses with less than 20 optical cycles directly from a Tm-doped fiber system, something that seems to be extremely challenging for other dopants in a fused silica fiber. In this contribution, we summarize the current development of our Thulium-doped fiber CPA system, demonstrate preliminary experiments for further scaling and discuss important design factors for the next steps. The current single-channel laser system presented herein delivers a pulse-peak power of 2 GW and a nearly transform-limited pulse duration of 200 fs in combination with 28.7 W of average power. Special care has been taken to reduce the detrimental impact of water vapor absorption by placing the whole system in a dry atmosphere housing (<0.1% rel. humidity) and by using a sufficiently long wavelength (1920-1980 nm). The utilization of a low-pressure chamber in the future will allow for the extension of the amplification bandwidth. Preliminary experiments demonstrating a broader amplification bandwidth that supports almost 100 fs pulse duration and average power scaling to < 100W have already been performed. Based on these results, a Tm-doped fiber CPA with sub-100 fs pulse duration, multi-GW pulse peak power and >100 W average power can be expected in the near future.

Optical coherence tomography (OCT) guided smart laser knife for cancer surgery (Conference Presentation)

NASA Astrophysics Data System (ADS)

Katta, Nitesh; Mcelroy, Austin; Estrada, Arnold; Milner, Thomas E.

2017-02-01

Neurological cancer surgeries require specialized tools that enhance imaging for precise cutting and removal of tissue without damaging adjacent neurological structures. The novel combination of high-resolution fast optical coherence tomography (OCT) alongside short pulsed nanosecond thulium (Tm) lasers offers stark advantages utilizing the superior beam quality, high volumetric tissue removal rates of thulium lasers with minimal residual thermal footprint in the tissue and avoiding damage to delicate sub-surface structures (e.g., nerves and microvessels); which has not been showcased before. A bench-top system is constructed, using a 15W 1940nm nanosecond pulsed Tm fiber laser (500uJ pulse energy, 100ns pulse duration, 30kHz repetition rate) for removing tissue and a swept source laser (1310±70nm, 100kHz sweep rate) is utilized for OCT imaging, forming a combined Tm/OCT system - a smart laser knife. The OCT image-guidance informs the Tm laser for cutting/removal of targeted tissue structures. Tissue phantoms were constructed to demonstrate surgical incision with blood vessel avoidance on the surface where 2mm wide 600um deep cuts are executed around the vessel using OCT to guide the procedure. Cutting up to delicate subsurface blood vessels (2mm deep) is demonstrated while avoiding damage to their walls. A tissue removal rate of 5mm^3/sec is obtained from the bench-top system. We constructed a blow-off model to characterize Tm cut depths taking into account the absorption coefficients and beam delivery systems to compute Arrhenius damage integrals. The model is used to compare predicted tissue removal rate and residual thermal injury with experimental values in response to Tm laser-tissue modification.

Androgen Deprivation Accelerates the Prostatic Urethra Wound Healing After Thulium Laser Resection of the Prostate by Promoting Re-Epithelialization and Regulating the Macrophage Polarization.

PubMed

Wang, Xing-Jie; Zhuo, Jian; Luo, Guang-Heng; Zhu, Yi-Ping; Yu, Dian-Jun; Zhao, Rui-Zhe; Jiang, Chen-Yi; Shi, Yun-Feng; Li, Hao; Chen, Lei; Hao, Kui-Yuan; Han, Xia; Zhao, Sheng; Bei, Xiao-Yu; Jing, Yi-Feng; Xia, Shu-Jie

2017-05-01

Complications after a thulium laser resection of the prostate (TmLRP) are related to re-epithelialization of the prostatic urethra. Since prostate growth and development are induced by androgen, the aim of this study was to determine the role and explore the mechanism of androgen in wound healing of the prostatic urethra. Beagles that received TmLRPs were randomly distributed into a castration group, a testosterone undecanoate (TU) group, and a control group. The prostate wound was assessed once a week using a cystoscope. Histological analysis was then carried out to study the re-epithelialization of the prostatic urethra in each group. The inflammatory response in the wound tissue and urine was also investigated. The healing of the prostatic urethra after a TmLRP was more rapid in the castration group and slower in the TU group than that in the control group. Castration accelerated re-epithelialization by promoting basal cell proliferation in the wound surface and beneath the wound and by accelerating the differentiation of basal cells into urothelial cells. Castration reduced the duration of the inflammatory phase and induced the conversion of M1 macrophages to M2 macrophages, thus accelerating the maturation of the wound. By contrast, androgen supplementation enhanced the inflammatory response and prolonged the inflammatory phase. Moreover, the anti-inflammatory phase was delayed and weakened. Androgen deprivation promotes re-epithelialization of the wound, regulates the inflammatory response, and accelerates wound healing of the prostatic urethra after a TmLRP. Prostate 77:708-717, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Qualification Testing of Laser Diode Pump Arrays for a Space-Based 2-micron Coherent Doppler Lidar

NASA Technical Reports Server (NTRS)

Amzajerdian, Farzin; Meadows, Byron L.; Baker, Nathaniel R.; Barnes, Bruce W.; Singh, Upendra N.; Kavaya, Michael J.

2007-01-01

The 2-micron thulium and holmium-based lasers being considered as the transmitter source for space-based coherent Doppler lidar require high power laser diode pump arrays operating in a long pulse regime of about 1 msec. Operating laser diode arrays over such long pulses drastically impact their useful lifetime due to the excessive localized heating and substantial pulse-to-pulse thermal cycling of their active regions. This paper describes the long pulse performance of laser diode arrays and their critical thermal characteristics. A viable approach is then offered that allows for determining the optimum operational parameters leading to the maximum attainable lifetime.

All-fiber laser at 1.94 µm: effect on soft tissue

NASA Astrophysics Data System (ADS)

Pal, Atasi; Pal, Debasis; Das Chowdhury, Sourav; Sen, Ranjan

2017-02-01

A focused laser beam at wavelength of strong water absorption at 1.94 μm can be a good scalpel for precision soft tissue surgery. A fiber Bragg grating-based, all-fiber, continuous-wave as well as modulated, cladding pumped, thulium-doped fiber laser at 1.94 μm has been configured to deliver up to 10 W of laser power under pumping at 793 nm having an efficiency of 32 %. The laser was exposed to freshly sacrificed chicken breast at different power level and exposure time. The formalin-fixed samples were examined by microscopy to identify the ablation region, carbonization and necrosis region for laser parameter optimization.

Double-Wall Carbon Nanotubes for Wide-Band, Ultrafast Pulse Generation

PubMed Central

2014-01-01

We demonstrate wide-band ultrafast optical pulse generation at 1, 1.5, and 2 μm using a single-polymer composite saturable absorber based on double-wall carbon nanotubes (DWNTs). The freestanding optical quality polymer composite is prepared from nanotubes dispersed in water with poly(vinyl alcohol) as the host matrix. The composite is then integrated into ytterbium-, erbium-, and thulium-doped fiber laser cavities. Using this single DWNT–polymer composite, we achieve 4.85 ps, 532 fs, and 1.6 ps mode-locked pulses at 1066, 1559, and 1883 nm, respectively, highlighting the potential of DWNTs for wide-band ultrafast photonics. PMID:24735347

Efficient, diode-pumped Tm3+:BaY2F8 vibronic laser

NASA Astrophysics Data System (ADS)

Cornacchia, F.; Parisi, D.; Bernardini, C.; Toncelli, A.; Tonelli, M.

2004-05-01

In this work we report the spectroscopy and laser results of several Thulium doped BaY2F8 single crystals grown using the Czochralski technique. The doping concentration is between 2at.% and 18at.%. We performed room temperature laser experiments pumping the samples with a laser diode at 789 nm obtaining 61% as maximum optical-to-optical efficiency with a maximum output power of 290 mW and a minimum lasing threshold of 26 mW. The lasing wavelength changed with the dopant concentration from 1927 nm up to 2030 nm and the nature of the transition changed from purely electronic to vibronic, accordingly.

HO:LULF and HO:LULF Laser Materials

NASA Technical Reports Server (NTRS)

Barnes, Norman P. (Inventor); Morrison, Clyde A. (Inventor); Filer, Elizabeth D. (Inventor); Jani, Mahendra G. (Inventor); Murray, Keith E. (Inventor); Lockard, George E. (Inventor)

1998-01-01

A laser host material LULF (LuLiF4) is doped with holmium (Ho) and thulium (Tm) to produce a new laser material that is capable of laser light production in the vicinity of 2 microns. The material provides an advantage in efficiency over conventional Ho lasers because the LULF host material allows for decreased threshold and upconversion over such hosts as YAG and YLF. The addition of Tm allows for pumping by commonly available GaAlAs laser diodes. For use with flashlamp pumping, erbium (Er) may be added as an additional dopant. For further upconversion reduction, the Tm can be eliminated and the Ho can be directly pumped.

Crystallographic phases in heavy rare earth metals under megabar pressures

NASA Astrophysics Data System (ADS)

Samudrala, G. K.; Vohra, Y. K.

2012-07-01

Experiments aimed at understanding the crystallographic phases of heavy rare earth metals were carried out in a diamond anvil cell at the Advanced Photon Source, Argonne National Laboratory. Heavy rare earth metals dysprosium (Dy), holmium (Ho), erbium (Er) and thulium (Tm) were compressed to multi-megabar pressures. The rare earth crystal sequence hcp→Sm-type→dhcp→distorted-fcc (dfcc) is observed in all four elements. Upon further compression, a structural transformation to a monoclinic C2/m phase has been observed. We summarize the results from these experiments and present Rietveld structural refinements on high pressure phases for the specific case of dysprosium.

Novel approach for solid state cryocoolers.

PubMed

Volpi, Azzurra; Di Lieto, Alberto; Tonelli, Mauro

2015-04-06

Laser cooling in solids is based on anti-Stokes luminescence, via the annihilation of lattice phonons needed to compensate the energy of emitted photons, higher than absorbed ones. Usually the anti-Stokes process is obtained using a rare-earth active ion, like Yb. In this work we demonstrate a novel approach for optical cooling based not only to Yb anti-Stokes cycle but also to virtuous energy-transfer processes from the active ion, obtaining an increase of the cooling efficiency of a single crystal LiYF(4) (YLF) doped Yb at 5at.% with a controlled co-doping of 0.0016% Thulium ions. A model for efficiency enhancement based on Yb-Tm energy transfer is also suggested.

Tunable narrow linewidth all-fiber thulium-doped fiber laser in a 2 µm-band using two Hi-Bi fiber optical loop mirrors

NASA Astrophysics Data System (ADS)

Posada-Ramírez, B.; Durán-Sánchez, M.; Álvarez-Tamayo, R. I.; Ibarra-Escamilla, B.; Hernández-Arriaga, M. V.; Sánchez-de-la-Llave, D.; Kuzin, E. A.

2017-08-01

We propose an all-fiber Tm-doped fiber laser with a tunable and narrow laser line generated in a wavelength region of 2 µm. A single laser line with a linewidth below 0.05 nm, tunable in a wavelength range of 44.25 nm, is obtained. The laser linewidth and the discrete wavelength tuning range depend on the characteristics of the two fiber optical loop mirrors with high birefringence in the loop that forms the cavity. Dual-wavelength laser operation is also observed at tuning range limits with a wavelength separation of 47 nm. Alternate wavelength switching is also observed.

50.4% slope efficiency thulium-doped large-mode-area fiber laser fabricated by powder technology.

PubMed

Darwich, Dia; Dauliat, Romain; Jamier, Raphaël; Benoit, Aurélien; Auguste, Jean-Louis; Grimm, Stephan; Kobelke, Jens; Schwuchow, Anka; Schuster, Kay; Roy, Philippe

2016-01-15

We report on a triple clad large-mode-area Tm-doped fiber laser with 18 μm core diameter manufactured for the first time by an alternative manufacturing process named REPUSIL. This reactive powder sinter material enables similar properties compared to conventional CVD-made fiber lasers, while offering the potential of producing larger and more uniform material. The fiber characterization in a laser configuration provides a slope efficiency of 47.7% at 20°C, and 50.4% at 0°C with 8 W output power, with a laser peak emission at 1970 nm. Finally, a beam quality near the diffraction-limit (M(x,y)2<1.1) is proved.

The Z2/A Dependence in Heavy-Ion Fusion for the Reactions of Chlorine on Thulium, Lutetium, Tantalum and Tungsten.

DTIC Science & Technology

1980-06-01

N NLL 0 0 C~CP (qw ) P /.op -40- individual excitation functions for each evaporation channel. For this study the lower...c’ + a" (alpha particles) =8a + a" (protons) £ £’ + P " (neutrons) C ’’, = 1 or 0 1ŕ,81","," = I or 0 V + V’ - I INDIVIDUAL (a, p or n ) VELOCITY...velocity profile of +10%, 0, -10% of v0 was taken. All angular distributions * - -- - - - - 76- M0 U3 LuL I M (0w DN~ N + 1 tJ < N I $ P ll7 -77-

Modelling of graphene Q-switched Tm lasers

NASA Astrophysics Data System (ADS)

Yasukevich, A. S.; Loiko, P.; Gusakova, N. V.; Serres, J. M.; Mateos, X.; Yumashev, K. V.; Kuleshov, N. V.; Petrov, V.; Griebner, U.; Aguiló, M.; Díaz, F.

2017-04-01

We report on a model of diode-pumped Thulium lasers passively Q-switched by a graphene saturable absorber applicable also for any other "fast" saturable absorber. It reasonably predicts the dependence of the pulse duration, pulse energy and pulse repetition frequency on the absorbed power. The model is applied in the present work for a Tm: KLuW microchip laser passively Q-switched with a multi-layer graphene saturable absorber. The laser generates 1 W at 1926 nm with a slope efficiency of 39%. Stable 190 ns /4.1 μJ pulses are achieved at a pulse repetition frequency of 260 kHz. The potential of graphene for the generation of few-ns pulses at 2 μm is discussed.

Watt-level ~2 μm laser output in Tm3+-doped tungsten tellurite glass double-cladding fiber.

PubMed

Li, Kefeng; Zhang, Guang; Hu, Lili

2010-12-15

We report, for the first time to the best of our knowledge, a watt level cw fiber laser at ~2 μm from a piece of 40-cm-long newly developed highly thulium-doped (3.76 × 10(20) ions/cm(3)) tungsten tellurite glass double cladding fiber pumped by a commercial 800 nm laser diode. The maximum output power of the fiber laser reaches 1.12 W. The slope efficiency and the optical-optical efficiency with respect to the absorbed pump are 20% and 16%, respectively. The lasing threshold is 1.46 W, and the lasing wavelength is centered at 1937 nm.

Thermodynamic Investigation of the Reduction-Distillation Process for Rare Earth Metals Production

NASA Astrophysics Data System (ADS)

Judge, W. D.; Azimi, G.

2017-10-01

Owing to their high vapor pressure, the four rare earth metals samarium, europium, thulium, and ytterbium are produced by reduction-distillation whereby their oxides are reduced with metallic lanthanum in vacuo, and the produced metal is subsequently vaporized off. Here, we performed a thorough thermodynamic investigation to establish a fundamental understanding of the reduction-distillation process. Thermodynamic functions including vapor pressures, Gibbs free energies, and enthalpies of reaction were calculated and compared with available experimental data. Furthermore, the kinetics of the process was explored and theoretical evaporation rates were calculated from thermodynamic data. The thermodynamic model developed in this work can help optimize processing conditions to maximize the yield and improve the overall process.

Comparison of different wavelength pump sources for Tm subnanosecond amplifier

NASA Astrophysics Data System (ADS)

Cserteg, Andras; Guillemet, Sébastien; Hernandez, Yves; Giannone, Domenico

2012-06-01

We report here a comparison of different pumping wavelengths for short pulse Thulium fibre amplifiers. We compare the results in terms of efficiency and required fibre length. As we operate the laser in the sub-nanosecond regime, the fibre length is a critical parameter regarding non linear effects. With 793 nm clad-pumping, a 4 m long active fibre was necessary, leading to strong spectral deformation through Self Phase Modulation (SPM). Core-pumping scheme was then more in-depth investigated with several wavelengths tested. Good results with Erbium and Raman shifted pumping sources were obtained, with very short fibre length, aiming to reach a few micro-joules per pulse without (or with limited) SPM.

Comparison of holmium:YAG and thulium fiber laser lithotripsy: ablation thresholds, ablation rates, and retropulsion effects.

PubMed

Blackmon, Richard L; Irby, Pierce B; Fried, Nathaniel M

2011-07-01

The holmium:YAG (Ho:YAG) laser lithotriptor is capable of operating at high pulse energies, but efficient operation is limited to low pulse rates (∼10 Hz) during lithotripsy. On the contrary, the thulium fiber laser (TFL) is limited to low pulse energies, but can operate efficiently at high pulse rates (up to 1000 Hz). This study compares stone ablation threshold, ablation rate, and retropulsion for the two different Ho:YAG and TFL operation modes. The TFL (λ = 1908 nm) was operated with pulse energies of 5 to 35 mJ, 500-μs pulse duration, and pulse rates of 10 to 400 Hz. The Ho:YAG laser (λ = 2120 nm) was operated with pulse energies of 30 to 550 mJ, 350-μs pulse duration, and a pulse rate of 10 Hz. Laser energy was delivered through 200- and 270-μm-core optical fibers in contact mode with human calcium oxalate monohydrate (COM) stones for ablation studies and plaster-of-Paris stone phantoms for retropulsion studies. The COM stone ablation threshold for Ho:YAG and TFL measured 82.6 and 20.8 J∕cm(2), respectively. Stone retropulsion with the Ho:YAG laser linearly increased with pulse energy. Retropulsion with TFL was minimal at pulse rates less than 150 Hz, then rapidly increased at higher pulse rates. For minimal stone retropulsion, Ho:YAG operation at pulse energies less than 175 mJ at 10 Hz and TFL operation at 35 mJ at 100 Hz is recommended, with both lasers producing comparable ablation rates. Further development of a TFL operating with both high pulse energies of 100 to 200 mJ and high pulse rates of 100 to 150 Hz may also provide an alternative to the Ho:YAG laser for higher ablation rates, when retropulsion is not a primary concern.

Image-guided smart laser system for precision implantation of cells in cartilage

NASA Astrophysics Data System (ADS)

Katta, Nitesh; Rector, John A.; Gardner, Michael R.; McElroy, Austin B.; Choy, Kevin C.; Crosby, Cody; Zoldan, Janet; Milner, Thomas E.

2017-03-01

State-of-the-art treatment for joint diseases like osteoarthritis focus on articular cartilage repair/regeneration by stem cell implantation therapy. However, the technique is limited by a lack of precision in the physician's imaging and cell deposition toolkit. We describe a novel combination of high-resolution, rapid scan-rate optical coherence tomography (OCT) alongside a short-pulsed nanosecond thulium (Tm) laser for precise cell seeding in cartilage. The superior beam quality of thulium lasers and wavelength of operation 1940 nm offers high volumetric tissue removal rates and minimizes the residual thermal footprint. OCT imaging enables targeted micro-well placement, precise cell deposition, and feature contrast. A bench-top system is constructed using a 15 W, 1940 nm, nanosecond-pulsed Tm fiber laser (500 μJ pulse energy, 100 ns pulse duration, 30kHz repetition rate) for removing tissue, and a swept source laser (1310 ± 70 nm, 100 kHz sweep rate) for OCT imaging, forming a combined Tm/OCT system - a "smart laser knife". OCT assists the smart laser knife user in characterizing cartilage to inform micro-well placement. The Tm laser creates micro-wells (2.35 mm diameter length, 1.5 mm width, 300 μm deep) and micro-incisions (1 mm wide, 200 μm deep) while OCT image-guidance assists and demonstrates this precision cutting and cell deposition with real-time feedback. To test micro-well creation and cell deposition protocol, gelatin phantoms are constructed mimicking cartilage optical properties and physiological structure. Cell viability is then assessed to illustrate the efficacy of the hydrogel deposition. Automated OCT feedback is demonstrated for cutting procedures to avoid important surface/subsurface structures. This bench-top smart laser knife system described here offers a new image-guided approach to precise stem cell seeding that can enhance the efficacy of articular cartilage repair.

Two-micrometer thulium laser resection of the prostate-tangerine technique in benign prostatic hyperplasia patients with previously negative transrectal prostate biopsy.

PubMed

Zhuo, Jian; Wei, Hai-Bin; Zhang, Fei; Liu, Hai-Tao; Zhao, Fu-Jun; Han, Bang-Min; Sun, Xiao-Wen; Xia, Shu-Jie

2017-01-01

The 2-μm thulium laser resection of the prostate-tangerine technique (TmLRP-TT) has been introduced as a minimally invasive treatment for benign prostatic hyperplasia (BPH). This study was undertaken to assess the clinical efficacy and safety of TmLRP-TT for the treatment of BPH patients with previously negative transrectal prostate biopsy. A prospective analysis of 51 patients with previously negative transrectal prostate biopsy who underwent surgical treatment using TmLRP-TT was performed from December 2011 to December 2013. Preoperative status, surgical details, and perioperative complications were recorded. The follow-up outcome was evaluated with subjective and objective tests at 1 and 6 months. TmLRP-TT was successfully completed in all patients. Mean prostate volume, operative duration, and catheterization time were 93.3 ± 37.9 ml, 69.5 ± 39.5 min, and 6.5 ± 1.3 days, respectively. The mean International Prostate Symptom Score, quality of life score, maximum urinary flow rate, and post-void residual urine volume changed notably at 6-month follow-up (22.5 ± 6.9 vs 6.1 ± 3.2, 4.8 ± 1.3 vs 1.1 ± 0.9, 7.3 ± 4.5 vs 18.9 ± 7.1 ml s-1 , and 148.7 ± 168.7 vs 28.4 ± 17.9 ml). Two (3.9%) patients required blood transfusion perioperatively, while 3 (5.9%) patients experienced transient hematuria postoperatively, and 2 (3.9%) patients received 3 days recatheterization due to clot retention. TmLRP-TT is a safe and effective minimally invasive technique for patients with previously negative transrectal prostate biopsy during the 6-month follow-up. This promising technology may be a feasible surgical method for previously negative transrectal prostate biopsy in the future.

Two-micrometer thulium laser resection of the prostate-tangerine technique in benign prostatic hyperplasia patients with previously negative transrectal prostate biopsy

PubMed Central

Zhuo, Jian; Wei, Hai-Bin; Zhang, Fei; Liu, Hai-Tao; Zhao, Fu-Jun; Han, Bang-Min; Sun, Xiao-Wen; Jun-Lu; Xia, Shu-Jie

2017-01-01

The 2-μm thulium laser resection of the prostate-tangerine technique (TmLRP-TT) has been introduced as a minimally invasive treatment for benign prostatic hyperplasia (BPH). This study was undertaken to assess the clinical efficacy and safety of TmLRP-TT for the treatment of BPH patients with previously negative transrectal prostate biopsy. A prospective analysis of 51 patients with previously negative transrectal prostate biopsy who underwent surgical treatment using TmLRP-TT was performed from December 2011 to December 2013. Preoperative status, surgical details, and perioperative complications were recorded. The follow-up outcome was evaluated with subjective and objective tests at 1 and 6 months. TmLRP-TT was successfully completed in all patients. Mean prostate volume, operative duration, and catheterization time were 93.3 ± 37.9 ml, 69.5 ± 39.5 min, and 6.5 ± 1.3 days, respectively. The mean International Prostate Symptom Score, quality of life score, maximum urinary flow rate, and post-void residual urine volume changed notably at 6-month follow-up (22.5 ± 6.9 vs 6.1 ± 3.2, 4.8 ± 1.3 vs 1.1 ± 0.9, 7.3 ± 4.5 vs 18.9 ± 7.1 ml s−1, and 148.7 ± 168.7 vs 28.4 ± 17.9 ml). Two (3.9%) patients required blood transfusion perioperatively, while 3 (5.9%) patients experienced transient hematuria postoperatively, and 2 (3.9%) patients received 3 days recatheterization due to clot retention. TmLRP-TT is a safe and effective minimally invasive technique for patients with previously negative transrectal prostate biopsy during the 6-month follow-up. This promising technology may be a feasible surgical method for previously negative transrectal prostate biopsy in the future. PMID:26732107

Thulium fiber laser lithotripsy in an in vitro ureter model

NASA Astrophysics Data System (ADS)

Hardy, Luke A.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

2014-12-01

Using a validated in vitro ureter model for laser lithotripsy, the performance of an experimental thulium fiber laser (TFL) was studied and compared to the clinical gold standard holmium:YAG laser. The holmium laser (λ=2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. The TFL (λ=1908 nm) was operated with 35 mJ, 500 μs, 150 to 500 Hz, and a 100-μm-core fiber. Urinary stones (60% calcium oxalate monohydrate/40% calcium phosphate) of uniform mass and diameter (4 to 5 mm) were laser ablated with fibers through a flexible video-ureteroscope under saline irrigation with flow rates of 22.7 and 13.7 ml/min for the TFL and holmium laser, respectively. The temperature 3 mm from the tube's center and 1 mm above the mesh sieve was measured by a thermocouple and recorded throughout each experiment for both lasers. Total laser and operation times were recorded once all stone fragments passed through a 1.5-mm sieve. The holmium laser time measured 167±41 s (n=12). TFL times measured 111±49, 39±11, and 23±4 s, for pulse rates of 150, 300, and 500 Hz, respectively (n=12 each). Mean peak saline irrigation temperatures reached 24±1°C for holmium, and 33±3°C, 33±7°C, and 39±6°C, for TFL at pulse rates of 150, 300, and 500 Hz, respectively. To avoid thermal buildup and provide a sufficient safety margin, TFL lithotripsy should be performed with pulse rates below 500 Hz and/or increased saline irrigation rates. The TFL rapidly fragmented kidney stones due in part to its high pulse rate, high power density, high average power, and observation of reduced stone retropulsion and may provide a clinical alternative to the conventional holmium laser for lithotripsy.

Kidney stone ablation times and peak saline temperatures during Holmium:YAG and Thulium fiber laser lithotripsy, in vitro, in a ureteral model

NASA Astrophysics Data System (ADS)

Hardy, Luke A.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

2015-02-01

Using a validated in vitro ureter model for laser lithotripsy, the performance of an experimental Thulium fiber laser (TFL) was studied and compared to clinical gold standard Holmium:YAG laser. The Holmium laser (λ = 2120 nm) was operated with standard parameters of 600 mJ, 350 μs, 6 Hz, and 270-μm-core optical fiber. TFL (λ = 1908 nm) was operated with 35 mJ, 500 μs, 150-500 Hz, and 100-μm-core fiber. Urinary stones (60% calcium oxalate monohydrate / 40% calcium phosphate), of uniform mass and diameter (4-5 mm) were laser ablated with fibers through a flexible video-ureteroscope under saline irrigation with flow rates of 22.7 ml/min and 13.7 ml/min for the TFL and Holmium laser, respectively. The temperature 3 mm from tube's center and 1 mm above mesh sieve was measured by a thermocouple and recorded during experiments. Total laser and operation times were recorded once all stone fragments passed through a 1.5-mm sieve. Holmium laser time measured 167 +/- 41 s (n = 12). TFL times measured 111 +/- 49 s, 39 +/- 11 s, and 23 +/- 4 s, for pulse rates of 150, 300, and 500 Hz (n = 12 each). Mean peak saline irrigation temperatures reached 24 +/- 1 °C for Holmium, and 33 +/- 3 °C, 33 +/- 7 °C, and 39 +/- 6 °C, for TFL at pulse rates of 150, 300, and 500 Hz. To avoid thermal buildup and provide a sufficient safety margin, TFL lithotripsy should be performed with pulse rates below 500 Hz and/or increased saline irrigation rates. The TFL rapidly fragmented kidney stones due in part to its high pulse rate, high power density, high average power, and reduced stone retropulsion, and may provide a clinical alternative to the conventional Holmium laser for lithotripsy.

Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy

NASA Astrophysics Data System (ADS)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-01-01

The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A "fiber muzzle brake" was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-outer-diameter, 360-μm-inner-diameter tube with a 275-μm-diameter through hole located 250 μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40±4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25±4 s (n=10) without visible distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers, respectively. The muzzle brake fiber tip simultaneously provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

Thulium fiber laser recanalization of occluded ventricular catheters in an ex vivo tissue model

NASA Astrophysics Data System (ADS)

Hutchens, Thomas C.; Gonzalez, David A.; Hardy, Luke A.; McLanahan, C. Scott; Fried, Nathaniel M.

2017-04-01

Hydrocephalus is a chronic medical condition that occurs in individuals who are unable to reabsorb cerebrospinal fluid (CSF) created within the ventricles of the brain. Treatment requires excess CSF to be diverted from the ventricles to another part of the body, where it can be returned to the vascular system via a shunt system beginning with a catheter within the ventricle. Catheter failures due to occlusion by brain tissues commonly occur and require surgical replacement of the catheter. In this preliminary study, minimally invasive clearance of occlusions is explored using an experimental thulium fiber laser (TFL), with comparison to a conventional holmium: yttrium aluminium garnet (YAG) laser. The TFL utilizes smaller optical fibers (<200-μm OD) compared with holmium laser (>450-μm OD), providing critical extra cross-sectional space within the 1.2-mm-inner-diameter ventricular catheter for simultaneous application of an endoscope for image guidance and a saline irrigation tube for visibility and safety. TFL ablation rates using 100-μm core fiber, 33-mJ pulse energy, 500-μs pulse duration, and 20- to 200-Hz pulse rates were compared to holmium laser using a 270-μm core fiber, 325-mJ, 300-μs, and 10 Hz. A tissue occluded catheter model was prepared using coagulated egg white within clear silicone tubing. An optimal TFL pulse rate of 50 Hz was determined, with an ablation rate of 150 μm/s and temperature rise outside the catheter of ˜10°C. High-speed camera images were used to explore the mechanism for removal of occlusions. Image guidance using a miniature, 0.7-mm outer diameter, 10,000 pixel endoscope was explored to improve procedure safety. With further development, simultaneous application of TFL with small fibers, miniature endoscope for image guidance, and irrigation tube for removal of tissue debris may provide a safe, efficient, and minimally invasive method of clearing occluded catheters in the treatment of hydrocephalus.

Experimental study of a VBG-based Tm : YLF slab laser at different output coupler parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duan, X M; Ding, Y; Dai, T Y

2015-04-30

The performance of a Tm : YLF slab laser is studied at different output coupler parameters. Use is made of a 20-mm-long a-cut slab crystal doped with 2.5 at. % thulium ions. With a volume Bragg grating and a Fabry – Perot etalon, the selected output wavelength of this Tm : YLF slab laser is 1908 nm. For the optimised output coupler with a transmission of 20% and a radius of curvature of 300 mm, the output power exceeds 74.1 W and the slope efficiency with respect to the absorbed pump power reaches 48.4%. In addition, the beam quality ofmore » the Tm : YLF slab laser is improved. (lasers)« less

The effect of La2O3 in Tm3+-doped germanate-tellurite glasses for ~2 μm emission

PubMed Central

Peng, Ya-Pei; Yuan, Xinqiang; Zhang, Junjie; Zhang, Long

2014-01-01

A germanate-tellurite glass (GeO2-TeO2-K2O-Nb2O5-La2O3) with thulium doping has been investigated for application as a laser material around 2.0 μm regions. Under the 808 nm laser diode pumped, intense 1.8 μm emission is obtained. Based on the absorption spectra, radiative properties are predicted using Judd-Ofelt theory. The maximum value of emission cross-section of Tm3+ around 1.8 μm can reach 1.46 × 10−20 cm2, which indicated that the germanate-tellurite glass may provide high gain as a good medium for efficient 1.8 μm laser system. PMID:24918516

Novel fiber optic tip designs and devices for laser surgery

NASA Astrophysics Data System (ADS)

Hutchens, Thomas Clifton

Fiber optic delivery of laser energy has been used for years in various types of surgical procedures in the human body. Optical energy provides several benefits over electrical or mechanical surgery, including the ability to selectively target specific tissue types while preserving others. Specialty fiber optic tips have also been introduced to further customize delivery of laser energy to the tissue. Recent evolution in lasers and miniaturization has opened up opportunities for many novel surgical techniques. Currently, ophthalmic surgeons use relatively invasive mechanical tools to dissect retinal deposits which occur in proliferative diabetic retinopathy. By using the tight focusing properties of microspheres combined with the short optical penetration depth of the Erbium:YAG laser and mid-IR fiber delivery, a precise laser scalpel can be constructed as an alternative, less invasive and more precise approach to this surgery. Chains of microspheres may allow for a self limiting ablation depth of approximately 10 microm based on the defocusing of paraxial rays. The microsphere laser scalpel may also be integrated with other surgical instruments to reduce the total number of handpieces for the surgeon. In current clinical laser lithotripsy procedures, poor input coupling of the Holmium:YAG laser energy frequently damages and requires discarding of the optical fiber. However, recent stone ablation studies with the Thulium fiber laser have provided comparable results to the Ho:YAG laser. The improved spatial beam profile of the Thulium fiber laser can also be efficiently coupled into a fiber approximately one third the diameter and reduces the risk of damaging the fiber input. For this reason, the trunk optical fiber minus the distal fiber tip can be preserved between procedures. The distal fiber tip, which degrades during stone ablation, could be made detachable and disposable. A novel, low-profile, twist-locking, detachable distal fiber tip interface was designed, assembled, and tested for use in Thulium fiber laser lithotripsy. A 1.00-mm-outer-diameter detachable fiber tip interface was designed, constructed, and tested ex vivo on urinary stones in the laboratory. Similar stone ablation rates between the previously studied tapered distal fiber tip and the detachable fiber tip were measured. For urologists desiring faster TFL lithotripsy procedures, the incorporation of detachable distal fiber tips allows for rapid replacement of damaged fiber tips without concern about the laser to trunk fiber connection. This method for preserving the trunk fiber could be a motivation for integrating a dedicated laser fiber into the ureteroscope, with detachable distal tips, thus freeing the working channel for the use of other surgical instruments. During laser lithotripsy, distal fiber tip degradation increases as the fiber core diameter decreases. However, smaller fiber diameters (≤ 200 microm) are more desirable because of increased saline irrigation rates in the single working channel of the ureteroscope and less impact on ureteroscope deflection. A hollow fiber cap is proposed to reduced fiber tip degradation in small diameter fibers, without compromising stone ablation rates. The disadvantage of the hollow fiber tip observed in the study is the increase in stone retropulsion. However, integrating the hollow fiber tip with a clinically used stone basket may allow for a robust stone ablation instrument that also minimizes retropulsion. These surgical approaches involving novel specialty fiber optic tip designs are discussed in this thesis.

Qcl Spectroscopy at 9 μM Calibrated with a High-Power Thulium-Based Frequency Comb

NASA Astrophysics Data System (ADS)

Mills, Andrew A.; Jiang, Jie; Hartl, Ingmar; Fermann, Martin; Gatti, Davide; Marangoni, Marco

2012-06-01

Optical frequency comb synthesizers (OFCS) comprised of mode-locked femtosecond lasers can be stabilized with Hertz-level accuracy and used in combination with cw lasers for high resolution spectroscopy. As currently established OFCS technologies are confined to the near-IR, mid-IR spectroscopy requires either down-conversion of near-IR combs or up-conversion of the probing laser. Due to the near-IR absorption edge of the nonlinear crystals with extended mid-IR transparency, the conversion efficiency of nonlinear processes increases with the wavelength of the interacting fields. A more straightforward and efficient link between comb and probing laser is thus expected to be obtained by increasing the wavelength of the comb synthesizer. In this work, the use of a novel, powerful Thulium-based OFCS with emission wavelengths near 2 μm is shown to be an excellent candidate to obtain absolute frequency calibration of quantum cascade lasers (QCL) operating at wavelengths as long as 9 μm. Specifically, by combining the frequencies of a 9 μm QCL with the high power 2 μm comb in a AgGaSe_2 crystal, SFG light is created near 1.6 μm. A portion of the 2 μm comb is non-linearly shifted to 1.6 μm. As the carrier envelope offset frequency (fceo) is the same for the SFG radiation and the shifted comb at 1.6 μm, heterodyning the two signals produces a beat signal independent of fceo, eliminating the need for an octave spanning comb and f-2f interferometer. We report on the development of this instrument, and the absolute line transitions of NH_3 at 9 μm, enabled by rapid scanning of the repetition rate of the comb enabled to increase the signal-to-noise ratio. J. Jiang, C. Mohr, J. Bethge, M. Fermann, and I. Hartl, in CLEO/Europe and EQEC 2011 Conference Digest, OSA Technical Digest (CD) PDB_1, 2001 D. Gatti, A. Gambetta, A. Castrillo, G. Galzerano, P. Laporta, L. Gainfrani and M. Marangoni Op. Exp. 19, 17520 2011

Miniature ball-tip optical fibers for use in thulium fiber laser ablation of kidney stones

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hardy, Luke A.; Kennedy, Joshua D.; Irby, Pierce B.; Fried, Nathaniel M.

2016-01-01

Optical fibers, consisting of 240-μm-core trunk fibers with rounded, 450-μm-diameter ball tips, are currently used during Holmium:YAG laser lithotripsy to reduce mechanical damage to the inner lining of the ureteroscope working channel during fiber insertion and prolong ureteroscope lifetime. Similarly, this study tests a smaller, 100-μm-core fiber with 300-μm-diameter ball tip during thulium fiber laser (TFL) lithotripsy. TFL was operated at a wavelength of 1908 nm, with 35-mJ pulse energy, 500-μs pulse duration, and 300-Hz pulse rate. Calcium oxalate/phosphate stone samples were weighed, laser procedure times were measured, and ablation rates were calculated for ball tip fibers, with comparison to bare tip fibers. Photographs of ball tips were taken before and after each procedure to track ball tip degradation and determine number of procedures completed before need for replacement. A high speed camera also recorded the cavitation bubble dynamics during TFL lithotripsy. Additionally, saline irrigation rates and ureteroscope deflection were measured with and without the presence of TFL fiber. There was no statistical difference (P>0.05) between stone ablation rates for single-use ball tip fiber (1.3±0.4 mg/s) (n=10), multiple-use ball tip fiber (1.3±0.5 mg/s) (n=44), and conventional single-use bare tip fibers (1.3±0.2 mg/s) (n=10). Ball tip durability varied widely, but fibers averaged greater than four stone procedures before failure, defined by rapid decline in stone ablation rates. Mechanical damage at the front surface of the ball tip was the limiting factor in fiber lifetime. The small fiber diameter did not significantly impact ureteroscope deflection or saline flow rates. The miniature ball tip fiber may provide a cost-effective design for safe fiber insertion through the ureteroscope working channel and into the ureter without risk of instrument damage or tissue perforation, and without compromising stone ablation efficiency during TFL lithotripsy.

Thermo-selective Tm(x)Ti(1-x)O(2-x/2) nanoparticles: from Tm-doped anatase TiO2 to a rutile/pyrochlore Tm2Ti2O7 mixture. An experimental and theoretical study with a photocatalytic application.

PubMed

Navas, Javier; Sánchez-Coronilla, Antonio; Aguilar, Teresa; De los Santos, Desireé M; Hernández, Norge C; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; Martín-Calleja, Joaquín

2014-11-07

This is an experimental and theoretical study of thulium doped TiO2 nanoparticles. From an experimental perspective, a method was used to synthesize thulium-doped TiO2 nanoparticles in which Tm(3+) replaces Ti(4+) in the lattice, which to our knowledge has neither been reported nor studied theoretically so far. Different proportions of anatase and rutile phases were obtained at different annealing temperatures, and XRD and Raman spectroscopy also revealed the presence of a pyrochlore phase (Tm2Ti2O7) at 1173 K. Thus, the structure of the Tm-doped nanoparticles was thermally-controlled. Furthermore, XPS showed the presence of Tm(3+) in the samples synthesized, which produces oxygen vacancies to maintain the local neutrality in the lattice. The presence of Tm(3+) in the samples led to changes in the UV-Vis absorption spectra, so they showed photoluminescence properties and new states in the band gap, which produce a new lower energy electronic transition than the main TiO2 one. Periodic DFT calculations were performed to understand the experimentally produced structures. The production of oxygen vacancies was analysed and the changes generated in the structure were fully detailed. The DOS and PDOS analyses confirmed the experimental results obtained using UV-Vis spectroscopy, and showed that the new electronic states in the band gap are due to interactions of the f state of Tm and the p state of O. Likewise, the charge study and the ELF analysis indicate that when Tm is introduced into the TiO2 structure, the Ti-O bond around the oxygen vacancy is strengthened. Finally, an example of a photocatalytic application was developed to show the high efficiency of the samples due to the heterojunction in the interfaces of the phases in the samples, which improved the charge separation and the good charge carrier mobility due to the presence of the pyrochlore phase, as was also shown theoretically.

Thulium fiber laser-induced vapor bubble dynamics using bare, tapered, ball, hollow steel, and muzzle brake fiber optic tips

NASA Astrophysics Data System (ADS)

Gonzalez, David A.; Hardy, Luke A.; Hutchens, Thomas C.; Irby, Pierce B.; Fried, Nathaniel M.

2018-03-01

This study characterizes laser-induced vapor bubble dynamics for five different distal fiber optic tip configurations, to provide insight into stone retropulsion commonly experienced during laser ablation of kidney stones. A thulium fiber laser with 1908-nm wavelength delivered 34-mJ energy per pulse at 500-μs pulse duration through five different fibers such as 100-μm-core / 170-μm-OD bare fiber tip, 150- to 300-μm-core tapered fiber tip, 100-μm-core / 300-μm-OD ball tip fiber, 100-μm-core / 340-μm-OD hollow steel tip fiber, and 100-μm-core / 560-μm-OD muzzle brake fiber tip. A high-speed camera with 10-μm-spatial and 9.5-μs-temporal resolution was used to image the vapor bubble dynamics. A needle hydrophone measured pressure transients in the forward (0 deg) and side (90 deg) directions while placed at a 6.8 ± 0.4 mm distance from the distal fiber tip. Maximum bubble dimensions (width/length) averaged 0.7/1.5, 1.0/1.6, 0.5/1.1, 0.8/1.9, and 0.7 / 1.5 mm, for bare, tapered, ball, hollow steel, and muzzle brake fiber tips, respectively (n = 5). The hollow steel tip exhibited the most elongated vapor bubble shape, translating into increased forward pressure in this study and consistent with higher stone retropulsion in previous reports. Relative pressures (a.u.) in (forward/side) directions averaged 1.7/1.6, 2.0/2.0, 1.4/1.2, 6.8/1.1, and 0.3/1.2, for each fiber tip (n = 5). For the hollow steel tip, forward pressure was 4 × higher than for the bare fiber. For the muzzle brake fiber tip, forward pressure was 5 × lower than the bare fiber. Bubble dimensions and pressure measurements demonstrated that the muzzle brake fiber tip reduced forward pressure by partially venting vapors through the portholes, which is consistent with the observation of lower stone retropulsion in previous reports.

Optical study of Tm-doped solid solution (Sc0.5Y0.5)2SiO5 crystal

NASA Astrophysics Data System (ADS)

Shi, Jiaojiao; Liu, Bin; Zheng, Lihe; Wang, Qingguo; Tang, Huili; Liu, Junfang; Su, Liangbi; Wu, Feng; Zhao, Hengyu; He, Nuotian; Li, Na; Li, Qiu; Guo, Chao; Xu, Jun; Yang, Kejian; Xu, Xiaodong; Ryba-Romanowski, Witold; Lisiecki, Radosław; Solarz, Piotr

2018-04-01

Tm-doped (Sc0.5Y0.5)2SiO5 (SYSO) crystals were grown by Czochralski method. The UV-VIR-NIR absorption spectra and the near-infrared emission spectra were measured and analysed by the Judd-Ofelt approach. Temperature influence on both absorption and emission spectra has been determined from the data recorded at room temperature and 10 K. It has been found that the structural disorder resulting from dissimilar ionic radii of Sc3+ and Y3+ in the solid solution (Sc0.5Y0.5)2SiO5 crystal brings about a strong inhomogeneous broadening of Tm3+ ions spectra. However, it affects the excited state relaxation dynamics inherent to thulium-doped Y2SiO5 and Sc2SiO5 hosts weakly.

Widely tunable short-infrared thulium and holmium doped fluorozirconate waveguide chip lasers.

PubMed

Lancaster, D G; Gross, S; Withford, M J; Monro, T M

2014-10-20

We report widely tunable (≈ 260 nm) Tm(3+) and Ho(3+) doped fluorozirconate (ZBLAN) glass waveguide extended cavity lasers with close to diffraction limited beam quality (M(2) ≈ 1.3). The waveguides are based on ultrafast laser inscribed depressed claddings. A Ti:sapphire laser pumped Tm(3+)-doped chip laser continuously tunes from 1725 nm to 1975 nm, and a Tm(3+)-sensitized Tm(3+):Ho(3+) chip laser displays tuning across both ions evidenced by a red enhanced tuning range of 1810 to 2053 nm. We also demonstrate a compact 790 nm diode laser pumped Tm(3+)-doped chip laser which tunes from 1750 nm to 1998 nm at a 14% incident slope efficiency, and a beam quality of M(2) ≈ 1.2 for a large mode-area waveguide with 70 µm core diameter.

Graphene Oxide saturable absorber for generating eye-safe Q-switched fiber laser

NASA Astrophysics Data System (ADS)

Rosol, A. H. A.; Jusoh, Z.; Rahman, H. A.; Rusdi, M. F. M.; Harun, S. W.; Latiff, A. A.

2017-06-01

This paper reports the generation of Q-switched fiber laser using thulium doped fiber (TDF) as a gain medium and graphene oxide (GO) as a saturable absorber (SA). The GO powder is embedded into polyvinyl alcohol (PVA) to form an SA film based on a drop-casting technique. GO-SA film is sandwiched between two fiber connectors and tighten by FC adapter before it is incorporated into an TDF laser cavity for Q-switching pulse generation. At 344 mW pump level, a stable Q-switching regime presence at 1943 nm with a 3-dB spectral bandwidth of 9 nm. The maximum repetition rate, pulse width, and pulse energy are at 25 kHz, 4.2 µs, and 0.68 µJ, respectively. All finding results are comparable with other reported pulse fiber lasers.

Passively Q-switched Tm-doped fiber laser based on concave gold bipyramids assembled quasi-2D saturable absorber

NASA Astrophysics Data System (ADS)

Song, Jiaxin; Wu, Hanshuo; Wu, Jian; Xu, Jiangming; Xiao, Hu; Leng, Jinyong; Zhou, Pu; Liu, Zejin

2018-07-01

We demonstrated a concave gold bipyramids (CAuBPs) quasi-2D saturable absorbers (SAs) based ~2 μm band fiber laser for the first time. CAuBPs were synthesized by using modified aqueous wet-chemical synthesis method. Through controlling the size and morphology of CAuBPs, the longitudinal surface plasmon resonance peak of CAuBPs based quasi-2D SA is tuned to be ~2 μm. Passively Q-switched lasing of thulium-doped fiber laser is achieved successfully with a maximum average output power of 9.72 mW and ~9% slope efficiency. The minimum pulse width is 4.56 µs at the repetition rate of 20 kHz. Experimental results reveals that CAuBPs could be used as SAs in the 2 µm region, which verifies the saturable absorption properties of CAuBPs.

Improved performances of CIBER-X: a new tabletop laser-driven electron and x-ray source

NASA Astrophysics Data System (ADS)

Girardeau-Montaut, Jean-Pierre; Kiraly, Bela; Girardeau-Montaut, Claire

2000-11-01

We present the most recent data concerning the performances of the table-top laser driven electron and x-ray source developed in our laboratory. X-ray pulses are produced by a three-step process which consists of the photoelectron emission from a thin metallic photocathode illuminated by 16 ps duration laser pulse at 213 nm. The e-gun is a standard pierce diode electrode type, in which electrons are accelerated by a cw electric fields of 12 MV/m. The photoinjector produced a train of 90 - 100 keV electron pulses of approximately 1 nC and 40 A peak current at a repetition rate of 10 Hz. The electrons, transported outside the diode, are focused onto a target of thulium by magnetic fields produced by two electromagnetic coils to produce x-rays. Applications to low dose imagery of inert and living materials are also presented.

Current-induced switching in a magnetic insulator

NASA Astrophysics Data System (ADS)

Avci, Can Onur; Quindeau, Andy; Pai, Chi-Feng; Mann, Maxwell; Caretta, Lucas; Tang, Astera S.; Onbasli, Mehmet C.; Ross, Caroline A.; Beach, Geoffrey S. D.

2017-03-01

The spin Hall effect in heavy metals converts charge current into pure spin current, which can be injected into an adjacent ferromagnet to exert a torque. This spin-orbit torque (SOT) has been widely used to manipulate the magnetization in metallic ferromagnets. In the case of magnetic insulators (MIs), although charge currents cannot flow, spin currents can propagate, but current-induced control of the magnetization in a MI has so far remained elusive. Here we demonstrate spin-current-induced switching of a perpendicularly magnetized thulium iron garnet film driven by charge current in a Pt overlayer. We estimate a relatively large spin-mixing conductance and damping-like SOT through spin Hall magnetoresistance and harmonic Hall measurements, respectively, indicating considerable spin transparency at the Pt/MI interface. We show that spin currents injected across this interface lead to deterministic magnetization reversal at low current densities, paving the road towards ultralow-dissipation spintronic devices based on MIs.

High-speed detection at two micrometres with monolithic silicon photodiodes

NASA Astrophysics Data System (ADS)

Ackert, Jason J.; Thomson, David J.; Shen, Li; Peacock, Anna C.; Jessop, Paul E.; Reed, Graham T.; Mashanovich, Goran Z.; Knights, Andrew P.

2015-06-01

With continued steep growth in the volume of data transmitted over optical networks there is a widely recognized need for more sophisticated photonics technologies to forestall a ‘capacity crunch’. A promising solution is to open new spectral regions at wavelengths near 2 μm and to exploit the long-wavelength transmission and amplification capabilities of hollow-core photonic-bandgap fibres and the recently available thulium-doped fibre amplifiers. To date, photodetector devices for this window have largely relied on III-V materials or, where the benefits of integration with silicon photonics are sought, GeSn alloys, which have been demonstrated thus far with only limited utility. Here, we describe a silicon photodiode operating at 20 Gbit s-1 in this wavelength region. The detector is compatible with standard silicon processing and is integrated directly with silicon-on-insulator waveguides, which suggests future utility in silicon-based mid-infrared integrated optics for applications in communications.

Enhancement of 800 nm upconversion emission in a thulium doped tellurite microstructured fiber pumped by a 1560 nm femtosecond fiber laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, Zhixu; Zheng, Kezhi; State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Changchun 130012

We report enhanced upconversion (UC) fluorescence in Tm{sup 3+} doped tellurite microstructured fibers (TDTMFs) fabricated by using a rod-in-tube method. Under the pumping of a 1560 nm femtosecond fiber laser, ultrabroadband supercontinuum light expanding from ∼1050 to ∼2700 nm was generated in a 4 cm long TDTMF. Simultaneously, intense 800 nm UC emission from the {sup 3}H{sub 4} → {sup 3}H{sub 6} transition of Tm{sup 3+} was observed in the same TDTMF. Compared to that pumped by a 1560 nm continuous wave fiber laser, the UC emission intensity was enhanced by ∼4.1 times. The enhancement was due to the spectral broadening in the TDTMF under themore » pumping of the 1560 nm femtosecond fiber laser.« less

Pulse dynamics of dual-wavelength dissipative soliton resonances and domain wall solitons in a Tm fiber laser with fiber-based Lyot filter.

PubMed

Wang, Pan; Zhao, Kangjun; Xiao, Xiaosheng; Yang, Changxi

2017-11-27

We report on the first demonstration of dual-wavelength square-wave pulses in a thulium-doped fiber laser. Under appropriate cavity parameters, dual-wavelength dissipative soliton resonances (DSRs) and domain wall solitons (DWSs) are successively obtained. Meanwhile, dark pulses generation is achieved at the dual-wavelength DWSs region due to the overlap of the two domain wall pulses. The fiber-based Lyot filter, conducted by inserting PMF between an in-line PBS and a PD-ISO, facilitates the generation of dual-wavelength operation. The polarization-resolved investigation suggests that the cross coupling between two orthogonal polarization components in the high nonlinear fiber plays an important role in the square-wave pulses formation. The investigation may be helpful for further understanding the square-wave pulse formation and has potential in application filed of multi-wavelength pulsed fiber lasers.

Dual comb generation from a mode-locked fiber laser with orthogonally polarized interlaced pulses.

PubMed

Akosman, Ahmet E; Sander, Michelle Y

2017-08-07

Ultra-high precision dual-comb spectroscopy traditionally requires two mode-locked, fully stabilized lasers with complex feedback electronics. We present a novel mode-locked operation regime in a thulium-holmium co-doped fiber laser, a frequency-halved state with orthogonally polarized interlaced pulses, for dual comb generation from a single source. In a linear fiber laser cavity, an ultrafast pulse train composed of co-generated, equal intensity and orthogonally polarized consecutive pulses at half of the fundamental repetition rate is demonstrated based on vector solitons. Upon optical interference of the orthogonally polarized pulse trains, two stable microwave RF beat combs are formed, effectively down-converting the optical properties into the microwave regime. These co-generated, dual polarization interlaced pulse trains, from one all-fiber laser configuration with common mode suppression, thus provide an attractive compact source for dual-comb spectroscopy, optical metrology and polarization entanglement measurements.

Superconducting composite with multilayer patterns and multiple buffer layers

DOEpatents

Wu, X.D.; Muenchausen, R.E.

1993-10-12

An article of manufacture is described including a substrate, a patterned interlayer of a material selected from the group consisting of magnesium oxide, barium-titanium oxide or barium-zirconium oxide, the patterned interlayer material overcoated with a secondary interlayer material of yttria-stabilized zirconia or magnesium-aluminum oxide, upon the surface of the substrate whereby an intermediate article with an exposed surface of both the overcoated patterned interlayer and the substrate is formed, a coating of a buffer layer selected from the group consisting of cerium oxide, yttrium oxide, curium oxide, dysprosium oxide, erbium oxide, europium oxide, iron oxide, gadolinium oxide, holmium oxide, indium oxide, lanthanum oxide, manganese oxide, lutetium oxide, neodymium oxide, praseodymium oxide, plutonium oxide, samarium oxide, terbium oxide, thallium oxide, thulium oxide, yttrium oxide and ytterbium oxide over the entire exposed surface of the intermediate article, and, a ceramic superconductor. 5 figures.

Magnetic hysteresis in a lanthanide molecular magnet dimer system

NASA Astrophysics Data System (ADS)

Atkinson, James; Cebulka, Rebecca; Del Barco, Enrique; Roubeau, Olivier; Velasco, Veronica; Barrios, Leo; Aromi, Guillem

Molecular magnets present a wonderful means for studying the dynamics of spin. Often synthesized as a crystal lattice of identical systems, ensemble measurements enable thorough detailing of the internal degrees of freedom. Here we present the results of characterization performed on a dimer system, CeTm(HL)2(H2L)NO3pyH2O (L = ligand, C45H31O15N3), consisting of two lanthanide spins (Cerium and Thulium) with expected local axial anisotropies tilted with respect to each other. Microwave EPR spectroscopy at low temperature reveals hysteresis in observed absorption features, with angle dependence studies indicating the presence of several ``easy axis'' orientations. We attempt to understand this system through modelling via a spin Hamiltonian, and to determine the strength and nature of the coupling between the lanthanide centers. This research was funded through NSF Grant # 24086159.

Observation of Squeezed Light in the 2 μ m Region

NASA Astrophysics Data System (ADS)

Mansell, Georgia L.; McRae, Terry G.; Altin, Paul A.; Yap, Min Jet; Ward, Robert L.; Slagmolen, Bram J. J.; Shaddock, Daniel A.; McClelland, David E.

2018-05-01

We present the generation and detection of squeezed light in the 2 μ m wavelength region. This experiment is a crucial step in realizing the quantum noise reduction techniques that will be required for future generations of gravitational-wave detectors. Squeezed vacuum is generated via degenerate optical parametric oscillation from a periodically poled potassium titanyl phosphate crystal, in a dual resonant cavity. The experiment uses a frequency stabilized 1984 nm thulium fiber laser, and squeezing is detected using balanced homodyne detection with extended InGaAs photodiodes. We have measured 4.0 ±0.1 dB of squeezing and 10.5 ±0.5 dB of antisqueezing relative to the shot noise level in the audio frequency band, limited by photodiode quantum efficiency. The inferred squeezing level directly after the optical parametric oscillator, after accounting for known losses and phase noise, is 10.7 dB.

408-fs SESAM mode locked Cr:ZnSe laser

NASA Astrophysics Data System (ADS)

Bu, Xiangbao; Shi, Yuhang; Xu, Jia; Li, Huijuan; Wang, Pu

2018-01-01

We report self-starting femtosecond operation of a 127-MHz SESAM mode locked Cr:ZnSe laser around 2420 nm. A thulium doped double clad fiber laser at 1908 nm was used as the pumping source. In the normal dispersion regime, stable pulse pairs with constant phase differences in the multipulse regime were observed. The maximum output power was 342 mW with respect to incident pump power of 4.8 W and the corresponding slope efficiency was 10.4%. By inserting a piece of sapphire plate, dispersion compensation was achieved and the intra-cavity dispersion was moved to the anomalous regime. A maximum output power of 403 mW was obtained and the corresponding slope efficiency was 12.2%. Pulse width was measured to be 408 fs by a collinear autocorrelator using two-photon absorption in an InGaAs photodiode. The laser spectrum in multipulse operation showed a clear periodic modulation.

Versatile large-mode-area femtosecond laser-written Tm:ZBLAN glass chip lasers.

PubMed

Lancaster, D G; Gross, S; Fuerbach, A; Heidepriem, H Ebendorff; Monro, T M; Withford, M J

2012-12-03

We report performance characteristics of a thulium doped ZBLAN waveguide laser that supports the largest fundamental modes reported in a rare-earth doped planar waveguide laser (to the best of our knowledge). The high mode quality of waveguides up to 45 um diameter (~1075 μm(2) mode-field area) is validated by a measured beam quality of M(2)~1.1 ± 0.1. Benefits of these large mode-areas are demonstrated by achieving 1.9 kW peak-power output Q-switched pulses. The 1.89 μm free-running cw laser produces 205 mW and achieves a 67% internal slope efficiency corresponding to a quantum efficiency of 161%. The 9 mm long planar chip developed for concept demonstration is rapidly fabricated by single-step optical processing, contains 15 depressed-cladding waveguides, and can operate in semi-monolithic or external cavity laser configurations.

Advances in Lasers for the Treatment of Stones-a Systematic Review.

PubMed

Kronenberg, Peter; Somani, Bhaskar

2018-05-17

Laser lithotripsy is increasingly used worldwide and is a continuously evolving field with new and extensive research being published every year. Variable pulse length Ho:YAG lithotripters allow new lithotripsy parameters to be manipulated, and there is an effort to integrate new technologies into lithotripters. Pulsed thulium lasers seem to be a viable alternative to holmium lasers. The performance of similar laser fibers varies from manufacturer to manufacturer. Special laser fibers and "cleaving only" fiber tip preparation can be beneficial for the lithotripsy procedure. Different laser settings and the surgical technique employed can have significant impact on the success of laser lithotripsy. When safely done, complications of laser lithotripsy are rare and concern the endoscopic nature of procedure, not the technology itself, making laser lithotripsy one of the safest tools in urology. Laser lithotripsy has had several new developments and more insight has been gained in recent years with many more advances expected in the future.

Thulium laser VapoResection of the prostate versus traditional transurethral resection of the prostate or transurethral plasmakinetic resection of prostate for benign prostatic obstruction: a systematic review and meta-analysis.

PubMed

Deng, Zheng; Sun, Menghao; Zhu, Yiping; Zhuo, Jian; Zhao, Fujun; Xia, Shujie; Han, Bangmin; Herrmann, Thomas R W

2018-04-12

To compare the efficacy and safety of thulium laser VapoResection of the prostate (ThuVaRP) versus standard traditional transurethral resection of the prostate (TURP) or plasmakinetic resection of prostate (PKRP) for benign prostatic obstruction. Systematic searches were performed in the Medline, EMBASE, the Cochrane Library, Web of Science, and CNKI in December 2017. The outcomes of demographic and clinical characteristics, perioperative variables, complications, and postoperative efficacy including International Prostate Symptom Score (IPSS), quality of life (QoL), maximum flow rate (Qmax), and postvoid residual (PVR) were assessed. 16 studies were selected in the meta-analysis including nine randomized controlled trials (RCTs) and seven non-RCTs. Among of them, nine studies compared ThuVaRP with PKRP, while seven studies compared ThuVaRP with TURP. It seemed that ThuVaRP needed longer operation time than TURP (WMD = 6.41, 95% CI 1.38-11.44, p = 0.01) and PKRP (WMD = 10.15, 95% CI 5.20-15.10, p < 0.0001). ThuVaRP was associated with less serum hemoglobin decreased, catheterization time, and the length of hospital stay compared with TURP (WMD = - 0.58, 95% CI - 0.77 to 0.38, p < 0.00001; WMD = - 1.89, 95% CI - 2.67 to 1.11, p < 0.00001; WMD = - 2.25, 95% CI - 2.91 to 1.60, p < 0.00001) and PKRP (WMD = - 0.28, 95% CI - 0.46 to 0.10, p = 0.002; WMD = - 1.88, 95% CI - 2.87 to 0.89, p = 0.0002; WMD = - 2.08, 95% CI - 2.63 to 1.54, p<0.00001). According to our assessment, there was no significantly difference in postoperative efficacy. The pooled data indicated that ThuVaRP had a nearly efficacy to TURP and PKRP based on IPSS, QoL, Qmax, and PVR. Although ThuVaRP was associated with longer operation time, it got distinct superiority on serum hemoglobin decreased, catheterization time, and hospital stay.

A randomised controlled trial to determine the clinical and cost effectiveness of thulium laser transurethral vaporesection of the prostate (ThuVARP) versus transurethral resection of the prostate (TURP) in the National Health Service (NHS) - the UNBLOCS trial: a study protocol for a randomised controlled trial.

PubMed

Worthington, Jo; Taylor, Hilary; Abrams, Paul; Brookes, Sara T; Cotterill, Nikki; Noble, Sian M; Page, Tobias; Swami, K Satchi; Lane, J Athene; Hashim, Hashim

2017-04-17

Transurethral resection of the prostate (TURP) has been the standard operation for benign prostatic obstruction (BPO) for 40 years, with approximately 25,000 procedures performed annually, and has remained largely unchanged. It is generally a successful operation, but has well-documented risks for the patient. Thulium laser transurethral vaporesection of the prostate (ThuVARP) vaporises and resects the prostate using a surgical technique similar to TURP. The small amount of study data currently available suggests that ThuVARP may have certain advantages over TURP, including reduced blood loss and shorter hospital stay, earlier return to normal activities, and shorter duration of catheterisation. A multicentre, pragmatic, randomised, controlled, parallel-group trial of ThuVARP versus standard TURP in men with BPO. Four hundred and ten men suitable for prostate surgery were randomised to receive either ThuVARP or TURP at four university teaching hospitals, and three district general hospitals. The key aim of the trial is to determine whether ThuVARP is equivalent to TURP judged on both the patient-reported International Prostate Symptom Score (IPSS) and the maximum urine flow rate (Qmax) at 12 months post-surgery. The general population has an increased life expectancy. As men get older their prostates enlarge, potentially causing BPO, which often requires surgery. Therefore, as the population ages, more prostate operations are needed to relieve obstruction. There is hence sustained interest in the condition and increasing need to find safer techniques than TURP. Various laser techniques have become available but none are widely used in the NHS because of lengthy training required for surgeons or inferior performance on clinical outcomes. Promising initial evidence from one RCT shows that ThuVARP has equivalent clinical effectiveness when compared to TURP, as well as other potential advantages. As ThuVARP uses a technique similar to that used in TURP, the learning curve is short, potentially making it also very quickly generalisable. This randomised study is designed to provide the high-quality evidence, in an NHS setting, with a range of patient-reported, clinical and cost-effectiveness outcomes, which will underpin and inform future NICE guidance. ISRCTN registry, ISRCTN00788389 . Registered on 20 September 2013.

Effects of fabrication methods on spin relaxation and crystallite quality in Tm-doped ? powders studied using spectral hole burning

NASA Astrophysics Data System (ADS)

Lutz, Thomas; Veissier, Lucile; Thiel, Charles W.; Woodburn, Philip J. T.; Cone, Rufus L.; Barclay, Paul E.; Tittel, Wolfgang

2016-01-01

High-quality rare-earth-ion (REI) doped materials are a prerequisite for many applications such as quantum memories, ultra-high-resolution optical spectrum analyzers and information processing. Compared to bulk materials, REI doped powders offer low-cost fabrication and a greater range of accessible material systems. Here we show that crystal properties, such as nuclear spin lifetime, are strongly affected by mechanical treatment, and that spectral hole burning can serve as a sensitive method to characterize the quality of REI doped powders. We focus on the specific case of thulium doped ? (Tm:YAG). Different methods for obtaining the powders are compared and the influence of annealing on the spectroscopic quality of powders is investigated on a few examples. We conclude that annealing can reverse some detrimental effects of powder fabrication and, in certain cases, the properties of the bulk material can be reached. Our results may be applicable to other impurities and other crystals, including color centers in nano-structured diamond.

Supercontinuum generation and lasing in thulium doped tellurite microstructured fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jia, Zhi-Xu; Liu, Lai; Yao, Chuan-Fei

2014-02-14

We report supercontinuum (SC) generation in Tm{sup 3+} doped tellurite microstructured fibers (TMFs) pumped by a 1.56 μm femtosecond fiber laser. In comparison with SC generation in undoped TMFs, the SC spectral bandwidth and the spectral intensity in the wavelength region of >1.9 μm are evidently enlarged in Tm{sup 3+} doped TMFs owing to the contribution of the combination of linear gain of Tm{sup 3+} and the nonlinear optical effects to spectral broadening. Furthermore, a transition from SC generation to 1.887 μm lasing (Tm{sup 3+}: {sup 3}F{sub 4}→{sup 3}H{sub 6} transition) is observed in Tm{sup 3+} doped TMFs by varying the pulse widthmore » of the pump laser from 0.29 to 3.47 ps, which gives the evidence of the above spectral broadening mechanism. This is the first observation of the transition from SC generation to lasing, to the best of our knowledge.« less

Energy transfer processes between Tm(3+) and Ho(3+) in LiYF4. Ph.D. Thesis Final Report

NASA Technical Reports Server (NTRS)

Oezen, Goenuel

1991-01-01

The spectroscopic properties of the crystal LiYF4 doped with Thulium (Tm) and Holmium (Ho) ions are studied. The basic processes are discussed that regulate the transfer of energy between these two ions in this crystal. In this system Tm is considered the donor ion and the Ho the acceptor ion. Spectral data were obtained on three samples available: LiYF4:Tm(3+) (0.5 percent), LiYF4:Ho(3+) (1 percent), and LiYF4:Tm(3+) (5 percent), Ho(3+) (0.2 percent). Spectral data, which include absorption, luminescence, excitation, and the response to pulsed excitation in a wide range of temperatures, allowed to look at the energy transfer processes by considering the kinetic evolution of the emission of the two ions (donor and acceptor) involved in the process and the basic spectroscopic properties related to them. This inclusive approach has led to the validation of the physical model.

WIND MEASUREMENTS WITH HIGH-ENERGY DOPPLER LIDAR

NASA Technical Reports Server (NTRS)

Koch, Grady J.; Kavaya, Michael J.; Barnes, Bruce W.; Beyon, Jeffrey Y.; Petros, Mulugeta; Jirong, Yu; Amzajerdian, Farzin; Slingh, Upendra N.

2006-01-01

Coherent lidars at 2-micron wavelengths from holmium or thulium solid-state lasers have been in use to measure wind for applications in meteorology, aircraft wake vortex tracking, and turbulence detection [1,2,3] These field-deployed lidars, however, have generally been of a pulse energy of a few millijoules, limiting their range capability or restricting operation to regions of high aerosol concentration such as the atmospheric boundary layer. Technology improvements in the form of high-energy pulsed lasers, low noise detectors, and high optical quality telescopes are being evaluated to make wind measurements to long ranges or low aerosol concentrations. This research is aimed at developing lidar technology for satellite-based observation of wind on a global scale. The VALIDAR project was initiated to demonstrate a high pulse energy coherent Doppler lidar. VALIDAR gets its name from the concept of validation lidar, in that it can serve as a calibration and validation source for future airborne and spaceborne lidar missions. VALIDAR is housed within a mobile trailer for field measurements.

The Z2/A dependence in heavy-ion fusion for the reactions of chlorine on thulium, lutetium, tantalum and tungsten. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

DiRienzo, A.C.

1980-06-01

Evaporation residues produced in the reactions 35Cl+169Tm and 37Cl+169Tm, 175Lu, 181Ta and 186W were observed at zero degree utilizing the Mass Inst of Tech.- Brookhaven Nat'l Lab Recoil Mass Spectrometer. The recoiling nuclei were separated from the beam and refocused onto a surface barrier detector by a combination of electrostatic and magnetic fields and magnetic quadrupole lenses. The residual nuclei are alpha radioactive and can thus be identified by a characteristic alpha line observed after the arrival pulse of the evaporation residue. The recoiling nuclei also pass through a gas ionization chamber whereas the decay alpha do not. A separatemore » anti-coincidence spectrum therefore displayed the alphas background free. Trends of evaporation residue cross section were charted versus Z sq (proton no.)/ A(atomic no.) and compared to statistical evaporation codes.« less

Passively Q-switched dual-wavelength thulium-doped fiber laser based on a multimode interference filter and a semiconductor saturable absorber

NASA Astrophysics Data System (ADS)

Wang, M.; Huang, Y. J.; Ruan, S. C.

2018-04-01

In this paper, we have demonstrated a theta cavity passively Q-switched dual-wavelength fiber laser based on a multimode interference filter and a semiconductor saturable absorber. Relying on the properties of the fiber theta cavity, the laser can operate unidirectionally without an optical isolator. A semiconductor saturable absorber played the role of passive Q-switch while a section of single-mode-multimode-single-mode fiber structure served as an multimode interference filter and was used for selecting the lasing wavelengths. By suitably manipulating the polarization controller, stable dual-wavelength Q-switched operation was obtained at ~1946.8 nm and ~1983.8 nm with maximum output power and minimum pulse duration of ~47 mW and ~762.5 ns, respectively. The pulse repetition rate can be tuned from ~20.2 kHz to ~79.7 kHz by increasing the pump power from ~2.12 W to ~5.4 W.

Soft tissue effects of the THC:YAG laser on canine vocal cords.

PubMed

Kay, S L; Oz, M C; Haber, M; Blitzer, A; Treat, M R; Trokel, S L

1992-09-01

Recently, a laser based on a thulium-holmium-chromium (THC) doped Yttrium-aluminum-garnet (YAG) rod has been developed that produces light of 2.15 microns wavelength and can be transmitted through a low OH- silica fiberoptic cable. This wavelength falls on one of the peaks of the energy absorption spectrum of water. Thus, the THC:YAG laser eliminates the disadvantage of a cumbersome delivery system found in the CO2 laser while still providing precise cutting and minimal tissue injury inherent in lasers emitting light absorbed by water. We evaluated the soft tissue effects of this laser on canine vocal cords. Ablative lesions were produced by the THC:YAG laser and histologically examined on postoperative days 1, 7, and 28. Results indicate that the depth of tissue penetration is easily controlled and the healing response to tissue injury is comparable to that of the CO2 laser. The THC:YAG laser should prove to be a superior laser for use in otorhinolaryngology, especially when adapted to a flexible endoscope.

Two-photon interference of weak coherent laser pulses recalled from separate solid-state quantum memories

NASA Astrophysics Data System (ADS)

Jin, Jeongwan; Slater, Joshua A.; Saglamyurek, Erhan; Sinclair, Neil; George, Mathew; Ricken, Raimund; Oblak, Daniel; Sohler, Wolfgang; Tittel, Wolfgang

2013-08-01

Quantum memories allowing reversible transfer of quantum states between light and matter are central to quantum repeaters, quantum networks and linear optics quantum computing. Significant progress regarding the faithful transfer of quantum information has been reported in recent years. However, none of these demonstrations confirm that the re-emitted photons remain suitable for two-photon interference measurements, such as C-NOT gates and Bell-state measurements, which constitute another key ingredient for all aforementioned applications. Here, using pairs of laser pulses at the single-photon level, we demonstrate two-photon interference and Bell-state measurements after either none, one or both pulses have been reversibly mapped to separate thulium-doped lithium niobate waveguides. As the interference is always near the theoretical maximum, we conclude that our solid-state quantum memories, in addition to faithfully mapping quantum information, also preserve the entire photonic wavefunction. Hence, our memories are generally suitable for future applications of quantum information processing that require two-photon interference.

Two-photon interference of weak coherent laser pulses recalled from separate solid-state quantum memories.

PubMed

Jin, Jeongwan; Slater, Joshua A; Saglamyurek, Erhan; Sinclair, Neil; George, Mathew; Ricken, Raimund; Oblak, Daniel; Sohler, Wolfgang; Tittel, Wolfgang

2013-01-01

Quantum memories allowing reversible transfer of quantum states between light and matter are central to quantum repeaters, quantum networks and linear optics quantum computing. Significant progress regarding the faithful transfer of quantum information has been reported in recent years. However, none of these demonstrations confirm that the re-emitted photons remain suitable for two-photon interference measurements, such as C-NOT gates and Bell-state measurements, which constitute another key ingredient for all aforementioned applications. Here, using pairs of laser pulses at the single-photon level, we demonstrate two-photon interference and Bell-state measurements after either none, one or both pulses have been reversibly mapped to separate thulium-doped lithium niobate waveguides. As the interference is always near the theoretical maximum, we conclude that our solid-state quantum memories, in addition to faithfully mapping quantum information, also preserve the entire photonic wavefunction. Hence, our memories are generally suitable for future applications of quantum information processing that require two-photon interference.

Interface induced ferromagnetism in topological insulator above room temperature

NASA Astrophysics Data System (ADS)

Tang, Chi; Chang, Cui-Zu; Liu, Yawen; Chen, Tingyong; Moodera, Jagadeesh; Shi, Jing

The quantum anomalous Hall effect (QAHE) observed in magnetic topological insulators (TI), an outcome of time reversal symmetry broken surface states, exhibits many exotic properties. However, a major obstacle towards high temperature QAHE is the low Curie temperature in the disordered magnetically doped TI systems. Here we report a study on heterostructures of TI and magnetic insulator in which the magnetic insulator, namely thulium iron garnet or TIG, has perpendicular magnetic anisotropy. At the TIG/TI interface, TIG magnetizes the surface states of the TI film by exchange coupling, as revealed by the anomalous Hall effect (AHE). We demonstrate that squared AHE hysteresis loops persist well above room temperature. The interface proximity induced high-temperature ferromagnetism in topological insulators opens up new possibilities for the realization of QAHE at high temperatures. This work was supported as part of the SHINES, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences under Award # SC0012670.

Broadband photocarrier dynamics and nonlinear absorption of PLD-grown WTe2 semimetal films

NASA Astrophysics Data System (ADS)

Gao, Wenbin; Huang, Lei; Xu, Jinlong; Chen, Yequan; Zhu, Chunhui; Nie, Zhonghui; Li, Yao; Wang, Xuefeng; Xie, Zhenda; Zhu, Shining; Xu, Jun; Wan, Xiangang; Zhang, Chao; Xu, Yongbing; Shi, Yi; Wang, Fengqiu

2018-04-01

WTe2 is a unique material in the family of transition metal dichalcogenides and it has been proposed as a candidate for type-II Weyl semimetals. However, thus far, studies on the optical properties of this emerging material have been significantly hindered by the lack of large-area, high-quality WTe2 materials. Here, we grow a centimeter-scale, highly crystalline WTe2 ultrathin film (˜35 nm) by a pulsed laser deposition technique. Broadband pump-probe spectroscopy (1.2-2.5 μm) reveals a peculiar ultrafast optical response where an initial photo-bleaching signal (lasting ˜3 ps) is followed by a long-lived photoinduced absorption signature. Nonlinear absorption characterization using femtosecond pulses confirms the saturable absorption response of the WTe2 ultrathin films, and we further demonstrated a mode-locked Thulium fiber laser using a WTe2 absorber. Our work provides important insights into linear and nonlinear optical responses of WTe2 thin films.

Surgical Management of Stones: New Technology

PubMed Central

Matlaga, Brian R.; Lingeman, James E.

2011-01-01

In recent years, the surgical treatment of kidney stone disease has undergone tremendous advances, many of which were possible only as a result of improvements in surgical technology. Rigid intracorporeal lithotrites, the mainstay of percutaneous nephrolithotomy, are now available as combination ultrasonic and ballistic devices. These combination devices have been reported to clear a stone burden with much greater efficiency than devices that operate by either ultrasonic or ballistic energy alone. The laser is the most commonly used flexible lithotrite; advances in laser lithotripsy have led to improvements in the currently utilized Holmium laser platform, as well as the development of novel laser platforms such as Thulium and Erbium devices. Our understanding of shock wave lithotripsy (SWL)has been improved over recent years as a consequence of basic science investigations. It is now recognized that there are certain maneuvers with SWL that the treating physician can do that will increase the likelihood of a successful outcome while minimizing the likelihood of adverse treatment-related events. PMID:19095207

First Measurement of Reaction-in-Flight Neutrons at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Tonchev, A.; Becker, J.; Bleuel, D.; Bionta, R.; Fortner, D.; Henry, E.; Khater, H.; Shaughnessy, D.; Schnider, D.; Stoeffl, W.; Yeamans, C.; Boswell, M.; Bredeweg, T.; Grim, G.; Jungman, G.; Fowler, M.; Hayes, A.; Obst, A.; Rundberg, R.; Schulz, A.; Wilhelmy, J.; Tornow, W.; Bhike, M.; Howell, C.; Gooden, M.; LLNL/LANL/TUNL Collaboration

2013-10-01

The first measurement of reaction-in-flight (RIF) neutrons, also known as tertiary neutrons, has been performed at the National Ignition Facility (NIF) using an activation technique. Thulium foils positioned at 50 cm from the burning deuterium-tritium (DT) capsule have been exposed to the characteristic DT neutron spectrum. The high-energy part of these neutrons with energies above 15.0 MeV can produce 167Tm via the 169Tm(n,3n) reaction. The 208-keV γ-ray, emitted from the decay of 167Tm with a half-life of 9.2 days, has been measured using two clover detectors. The first preliminary result implies that the ratio of RIF neutrons (En > 15.0 MeV) versus the total neutrons is 1 × 10 -4 +/- 3 × 10 -5. The important implication of these measurements on our knowledge of the charged-particle stopping power in strongly coupled quantum-degenerate plasma will be presented. This work was performed under the auspices of the Lawrence Livermore National Security, LLC, (LLNS) under Contract No. DE-AC52-07NA27344.

Proposal and proof-of-principle demonstration of non-destructive detection of photonic qubits using a Tm:LiNbO3 waveguide

PubMed Central

Sinclair, N.; Heshami, K.; Deshmukh, C.; Oblak, D.; Simon, C.; Tittel, W.

2016-01-01

Non-destructive detection of photonic qubits is an enabling technology for quantum information processing and quantum communication. For practical applications, such as quantum repeaters and networks, it is desirable to implement such detection in a way that allows some form of multiplexing as well as easy integration with other components such as solid-state quantum memories. Here, we propose an approach to non-destructive photonic qubit detection that promises to have all the mentioned features. Mediated by an impurity-doped crystal, a signal photon in an arbitrary time-bin qubit state modulates the phase of an intense probe pulse that is stored during the interaction. Using a thulium-doped waveguide in LiNbO3, we perform a proof-of-principle experiment with macroscopic signal pulses, demonstrating the expected cross-phase modulation as well as the ability to preserve the coherence between temporal modes. Our findings open the path to a new key component of quantum photonics based on rare-earth-ion-doped crystals. PMID:27853153

Fast switching and signature of efficient domain wall motion driven by spin-orbit torques in a perpendicular anisotropy magnetic insulator/Pt bilayer

NASA Astrophysics Data System (ADS)

Avci, Can Onur; Rosenberg, Ethan; Baumgartner, Manuel; Beran, Lukáš; Quindeau, Andy; Gambardella, Pietro; Ross, Caroline A.; Beach, Geoffrey S. D.

2017-08-01

We report fast and efficient current-induced switching of a perpendicular anisotropy magnetic insulator thulium iron garnet by using spin-orbit torques (SOT) from the Pt overlayer. We first show that, with quasi-DC (10 ms) current pulses, SOT-induced switching can be achieved with an external field as low as 2 Oe, making TmIG an outstanding candidate to realize efficient switching in heterostructures that produce moderate stray fields without requiring an external field. We then demonstrate deterministic switching with fast current pulses (≤20 ns) with an amplitude of ˜1012 A/m2, similar to all-metallic structures. We reveal that, in the presence of an initially nucleated domain, the critical switching current is reduced by up to a factor of five with respect to the fully saturated initial state, implying efficient current-driven domain wall motion in this system. Based on measurements with 2 ns-long pulses, we estimate the domain wall velocity of the order of ˜400 m/s per j = 1012 A/m2.

Massively parallel sensing of trace molecules and their isotopologues with broadband subharmonic mid-infrared frequency combs

NASA Astrophysics Data System (ADS)

Muraviev, A. V.; Smolski, V. O.; Loparo, Z. E.; Vodopyanov, K. L.

2018-04-01

Mid-infrared spectroscopy offers supreme sensitivity for the detection of trace gases, solids and liquids based on tell-tale vibrational bands specific to this spectral region. Here, we present a new platform for mid-infrared dual-comb Fourier-transform spectroscopy based on a pair of ultra-broadband subharmonic optical parametric oscillators pumped by two phase-locked thulium-fibre combs. Our system provides fast (7 ms for a single interferogram), moving-parts-free, simultaneous acquisition of 350,000 spectral data points, spaced by a 115 MHz intermodal interval over the 3.1-5.5 µm spectral range. Parallel detection of 22 trace molecular species in a gas mixture, including isotopologues containing isotopes such as 13C, 18O, 17O, 15N, 34S, 33S and deuterium, with part-per-billion sensitivity and sub-Doppler resolution is demonstrated. The technique also features absolute optical frequency referencing to an atomic clock, a high degree of mutual coherence between the two mid-infrared combs with a relative comb-tooth linewidth of 25 mHz, coherent averaging and feasibility for kilohertz-scale spectral resolution.

20-W 1952-nm tandem hybrid single and double clad TDFA

NASA Astrophysics Data System (ADS)

Romano, Clément; Tench, Robert E.; Delavaux, Jean-Marc

2018-02-01

A simple engineering design is important for achieving high Thulium-doped amplifier (TDFA) performance such as good power conversion, low noise figure (NF), scalable output power, high gain, and stable operation over a large dynamic range. In this paper we report the design, performance, and simulation of two stage high-power 1952 nm hybrid single and double clad TDFAs. The first stage of our hybrid amplifier is a single clad design, and the second stage is a double clad design. We demonstrate TDFAs with an output power greater than 20 W with single-frequency narrow linewidth (i.e. MHz) input signals at both 1952 and 2004 nm. An optical 10 dB bandwidth of 80 nm is derived from the ASE spectrum. The power stage is constructed with 10 μm core active fibers showing a maximum optical slope efficiency greater than 50 %. The experimental results lead to a 1 dB agreement with our simulation tool developed for single clad and double clad TDFAs. Overall this hybrid amplifier offers versatile features with the potential of much higher output power.

Quantum sized Ag nanocluster assisted fluorescence enhancement in Tm{sup 3+}-Yb{sup 3+} doped optical fiber beyond plasmonics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chattopadhyay, Rik; Haldar, Arindam; Paul, Mukul C.

2015-12-07

We report a process for enhancing fluorescence emission from conventional rare earth ions in optical fiber by metal nanocluster (MNC) in nonresonant indirect pumping. The process is completely different from formal metal enhanced fluorescence phenomenon as the MNCs are too small in size to support localized surface plasmon and the excitation wavelength is far from plasmon resonance frequency. We used an established theory of two coupled oscillators to explain the simultaneous enhancement of Ytterbium (Yb{sup 3+}) and Thulium (Tm{sup 3+}) emission by silver (Ag) NCs under nonresonant pumping in optical fiber. The fiber is pumped with a 980 nm fiber pigtailedmore » laser diode with input power of 20–100 mW to excite the Yb{sup 3+}. Four times enhancement of Yb{sup 3+} emission of 900–1100 nm and Tm{sup 3+} upconversion emission around 474 nm, 650 nm, and 790 nm is observed in the fiber with Ag NCs.« less

Antiferromagnetic Spin Coupling between Rare Earth Adatoms and Iron Islands Probed by Spin-Polarized Tunneling

PubMed Central

Coffey, David; Diez-Ferrer, José Luis; Serrate, David; Ciria, Miguel; Fuente, César de la; Arnaudas, José Ignacio

2015-01-01

High-density magnetic storage or quantum computing could be achieved using small magnets with large magnetic anisotropy, a requirement that rare-earth iron alloys fulfill in bulk. This compelling property demands a thorough investigation of the magnetism in low dimensional rare-earth iron structures. Here, we report on the magnetic coupling between 4f single atoms and a 3d magnetic nanoisland. Thulium and lutetium adatoms deposited on iron monolayer islands pseudomorphically grown on W(110) have been investigated at low temperature with scanning tunneling microscopy and spectroscopy. The spin-polarized current indicates that both kind of adatoms have in-plane magnetic moments, which couple antiferromagnetically with their underlying iron islands. Our first-principles calculations explain the observed behavior, predicting an antiparallel coupling of the induced 5d electrons magnetic moment of the lanthanides with the 3d magnetic moment of iron, as well as their in-plane orientation, and pointing to a non-contribution of 4f electrons to the spin-polarized tunneling processes in rare earths. PMID:26333417

Tm-doped fiber laser mode-locking with MoS2-polyvinyl alcohol saturable absorber

NASA Astrophysics Data System (ADS)

Cao, Liming; Li, Xing; Zhang, Rui; Wu, Duanduan; Dai, Shixun; Peng, Jian; Weng, Jian; Nie, Qiuhua

2018-03-01

We have designed an all-fiber passive mode-locking thulium-doped fiber laser that uses molybdenum disulfide (MoS2) as a saturable absorber (SA) material. A free-standing few-layer MoS2-polyvinyl alcohol (PVA) film is fabricated by liquid phase exfoliation (LPE) and is then transferred onto the end face of a fiber connector. The excellent saturable absorption of the fabricated MoS2-based SA allows the laser to output soliton pulses at a pump power of 500 mW. Fundamental frequency mode-locking is realized at a repetition frequency of 13.9 MHz. The central wavelength is 1926 nm, the 3 dB spectral bandwidth is 2.86 nm and the pulse duration is 1.51 ps. Additionally, third-order harmonic mode-locking of the laser is also achieved. The pulse duration is 1.33 ps, which is slightly narrower than the fundamental frequency mode-locking bandwidth. The experimental results demonstrate that the few-layer MoS2-PVA SA is promising for use in 2 μm laser systems.

1.9 μm square-wave passively Q-witched mode-locked fiber laser.

PubMed

Ma, Wanzhuo; Wang, Tianshu; Su, Qingchao; Wang, Furen; Zhang, Jing; Wang, Chengbo; Jiang, Huilin

2018-05-14

We propose and demonstrate the operation of Q-switched mode-locked square-wave pulses in a thulium-holmium co-doped fiber laser. By using a nonlinear amplifying loop mirror, continuous square-wave dissipative soliton resonance pulse is obtained with 4.4 MHz repetition rate. With the increasing pump power, square-wave pulse duration can be broadened from 1.7 ns to 3.2 ns. On such basis Q-switched mode-locked operation is achieved by properly setting the pump power and the polarization controllers. The internal mode-locked pulses in Q-switched envelope still keep square-wave type. The Q-switched repetition rate can be varied from 41.6 kHz to 74 kHz by increasing pump power. The corresponding average single-pulse energy increases from 2.67 nJ to 5.2 nJ. The average peak power is also improved from 0.6 W to 1.1 W when continuous square-wave operation is changed into Q-switched mode-locked operation. It indicates that Q-switched mode-locked operation is an effective method to increase the square-wave pulse energy and peak power.

2-μm optical time domain reflectometry measurements from novel Al-, Ge-, CaAlSi- doped and standard single-mode fibers

NASA Astrophysics Data System (ADS)

Rodriguez-Novelo, J. C.; Sanchez-Nieves, J. A.; Sierra-Calderon, A.; Sanchez-Lara, R.; Alvarez-Chavez, J. A.

2017-08-01

The development of novel Al-, Ge- doped and un-doped standard single mode fibers for future optical communication at 2μm requires the integration of, among other pieces of equipment, an optical time domain reflectometry (OTDR) technique for precise spectral attenuation characterization, including the well-known cut-back method. The integration of a state of the art OTDR at 2μm could provide valuable attenuation information from the aforementioned novel fibers. The proposed setup consists of a 1.7 mW, 1960nm pump source, a 30 dB gain Thulium doped fibre amplifier at 2μm, an 0.8mm focal length lens with a 0.5 NA, a 30 MHz acusto-optic modulator, a 3.1 focal length lens with a 0.68NA, an optical circulator at 2μm, an InGaAs photodetector for 1.2 nm-2.6 nm range, a voltage amplifier and an oscilloscope. The propagated pulse rate is 50 KHz, with 500 ns, 200 ns, 100 ns and 50 ns pulse widths. Attenuation versus novel fibers types for lengths ranging from 400- to 1000- meter samples were obtained using the proposed setup.

High quality TmIG films with perpendicular magnetic anisotropy grown by sputtering

NASA Astrophysics Data System (ADS)

Wu, C. N.; Tseng, C. C.; Yeh, S. L.; Lin, K. Y.; Cheng, C. K.; Fanchiang, Y. T.; Hong, M.; Kwo, J.

Ferrimagnetic thulium iron garnet (TmIG) films grown on gadolinium gallium garnet substrates recently showed stress-induced perpendicular magnetic anisotropy (PMA), attractive for realization of quantum anomalous Hall effect (QAHE) of topological insulator (TI) films via the proximity effect. Moreover, current induced magnetization switching of Pt/TmIG has been demonstrated for the development of room temperature (RT) spintronic devices. In this work, high quality TmIG films (about 25nm) were grown by sputtering at RT followed by post-annealing. We showed that the film composition is tunable by varying the growth parameters. The XRD results showed excellent crystallinity of stoichiometric TmIG films with an out-of-plane lattice constant of 1.2322nm, a narrow film rocking curve of 0.017 degree, and a film roughness of 0.2 nm. The stoichiometric films exhibited PMA and the saturation magnetization at RT was 109 emu/cm3 (RT bulk value 110 emu/cm3) with a coercive field of 2.7 Oe. In contrast, TmIG films of Fe deficiency showed in-plane magnetic anisotropy. The high quality sputtered TmIG films will be applied to heterostructures with TIs or metals with strong spin-orbit coupling for novel spintronics.

UV-visible-NIR light generation through frequency upconversion in Tm3+-doped low silica calcium aluminosilicate glasses using multiple excitation around 1.2 μm

NASA Astrophysics Data System (ADS)

Trindade, C. M.; Rego-Filho, F. G.; Astrath, N. G. C.; Jacinto, C.; Gouveia-Neto, A. S.

2018-04-01

Intense ultraviolet upconversion emission was produced in single Tm3+-doped OH--free low silica calcium aluminosilicate glasses. A new excitation route based upon multi-Stokes Raman emissions generated in an optical fiber pumped at 1.064 μm, and exploiting the absorption band around 1.2 μm by means of the 3H5 thulium excited state, was used. Furthermore, the other bands of the stimulated Raman scattering spectrum resonantly enhances all the upconversion processes, resulting in efficient ultraviolet (295 nm, 360 nm), blue (456 nm, 480 nm), red (650 nm, 667 nm), and near-infrared (800 nm) emissions. The population of the 1P0, 1D2, 1G4, 3F2 and 3H4 excited-state emitting levels was accomplished through stepwise multi-photon absorption. Results indicate competing cross-relaxation processes involving Tm3+ ion-pairs producing UV emission population quenching Simplified energy-level diagram of Tm3+- doped sample excited using multi-stokes emissions. The λp indication describes all excitation wavelengths, represented by a single arrow for the sake of simplicity.

Probing structure, thermochemistry, electron affinity, and magnetic moment of thulium-doped silicon clusters TmSi n (n = 3-10) and their anions with density functional theory.

PubMed

Huang, Xintao; Yang, Jucai

2017-12-26

The most stable structures and electronic properties of TmSi n (n = 3-10) clusters and their anions have been probed by using the ABCluster global search technique combined with the PBE, TPSSh, and B3LYP density functional methods. The results revealed that the most stable structures of neutral TmSi n and their anions can be regarded as substituting a Si atom of the ground state structure of Si n + 1 with a Tm atom. The reliable AEAs, VDEs and simulated PES of TmSi n (n = 3-10) are presented. Calculations of HOMO-LUMO gap revealed that introducing Tm atom to Si cluster can improve photochemical reactivity of the cluster. The NPA analyses indicated that the 4f electron of Tm atom in TmSi n (n = 3-10) and their anions do not participate in bonding. The total magnetic moments of TmSi n are mainly provided by the 4f electrons of Tm atom. The dissociation energy of Tm atom from the most stable structure of TmSi n and their anions has been calculated to examine relative stability.

Superconducting composite with multilayer patterns and multiple buffer layers

DOEpatents

Wu, Xin D.; Muenchausen, Ross E.

1993-01-01

An article of manufacture including a substrate, a patterned interlayer of a material selected from the group consisting of magnesium oxide, barium-titanium oxide or barium-zirconium oxide, the patterned interlayer material overcoated with a secondary interlayer material of yttria-stabilized zirconia or magnesium-aluminum oxide, upon the surface of the substrate whereby an intermediate article with an exposed surface of both the overcoated patterned interlayer and the substrate is formed, a coating of a buffer layer selected from the group consisting of cerium oxide, yttrium oxide, curium oxide, dysprosium oxide, erbium oxide, europium oxide, iron oxide, gadolinium oxide, holmium oxide, indium oxide, lanthanum oxide, manganese oxide, lutetium oxide, neodymium oxide, praseodymium oxide, plutonium oxide, samarium oxide, terbium oxide, thallium oxide, thulium oxide, yttrium oxide and ytterbium oxide over the entire exposed surface of the intermediate article, and, a ceramic superco n FIELD OF THE INVENTION The present invention relates to the field of superconducting articles having two distinct regions of superconductive material with differing in-plane orientations whereby the conductivity across the boundary between the two regions can be tailored. This invention is the result of a contract with the Department of Energy (Contract No. W-7405-ENG-36).

Best laser for prostatectomy in the year 2013.

PubMed

Maheshwari, Pankaj N; Joshi, Nitin; Maheshwari, Reeta P

2013-07-01

Lasers have come a long way in the management of benign prostatic hyperplasia. Over last nearly two decades, various different lasers have been utilized for prostatectomy. Neodymium: yttrium-aluminum-garnet laser that started this journey, is no longer used for prostatectomy. Holmium laser can achieve transurethral enucleation of the prostatic adenoma producing a fossa that can be compared with the fossa after Freyer's prostatectomy. Green light laser has a short learning curve, is nearly blood-less with good immediate results. Thulium laser is a faster cutting laser while diode laser is a portable laser device. Often laser prostatectomy is considered as a replacement for the standard transurethral resection of prostate (TURP). To be comparable, laser should reduce or avoid the immediate and long-term complications of TURP, especially bleeding and need for blood transfusion. It should also be safe in the ever increasing patient population on antiplatelet and anticoagulant drugs. We need to take stock of the situation and identify, which among the present day lasers has stood the test of time. A review of the literature was performed to see if any of these lasers could be called the "best laser for prostatectomy in 2013."

Spectroscopic analysis of the NIR emission in Tm implanted Al{sub x}Ga{sub 1-x}N layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodrigues, J., E-mail: joana.catarina@ua.pt; Esteves, T. C.; Santos, N. F.

2016-08-28

Al{sub x}Ga{sub 1-x}N samples, with different AlN molar fractions, x = 0, 0.15, 0.77, and 1, grown by halide vapor phase epitaxy were implanted with Tm ions. Photoluminescence (PL) measurements revealed that after thermal annealing all the samples exhibit intraionic Tm{sup 3+} luminescence. In samples with x > 0, the low temperature emission is dominated by the lines that appear in the near infrared (NIR) spectral region, corresponding to the overlapped {sup 1}G{sub 4} → {sup 3}H{sub 5} and {sup 3}H{sub 4} → {sup 3}H{sub 6} multiplet transitions. A detailed spectroscopic analysis of NIR emission of the thulium implanted and annealed Al{sub x}Ga{sub 1-x}Nmore » layers is presented by using temperature dependent steady-state PL, room temperature PL excitation, and time resolved PL. The results indicate that the excitonic features sensitive to the alloy disorder are involved in the excitation population processes of the Tm{sup 3+} luminescence and the highest thermal stability for the NIR emission occurs for the AlN:Tm sample.« less

Miniature ureteroscope tip designs for use in thulium fiber laser lithotripsy

NASA Astrophysics Data System (ADS)

Kennedy, Joshua D.; Wilson, Christopher R.; Irby, Pierce B.; Fried, Nathaniel M.

2017-02-01

A miniature ureteroscope has the potential to eliminate need for full anesthesia and dilation, increase comfort and safety of laser lithotripsy via ureteroscopy, and reduce hospital costs via an office based procedure. A prototype, 4.5 Fr (1.5-mm-OD), five channel ureteroscope tip was developed, housing a 200-μm-ID central channel for insertion of small, 100-μm-core fibers and four surrounding channels, each with 510-μm-ID for instrumentation, irrigation, imaging, and illumination, respectively. Common urological instruments (including fibers, guidewires, and stone baskets) were inserted through tip's working channels to demonstrate feasibility. Low irrigation rates were measured, revealing a need for manual pump-assisted irrigation. Imaging was conducted using 3k, 6k, and 10k pixel miniature flexible endoscopes with 0.4, 0.6, and 0.9 mm outer diameters, respectively. The 3k pixel endoscope with integrated illumination was inserted through the prototype unimpeded, and successfully demonstrated ability to differentiate between hard tissues (e.g. kidney stones) and soft tissues (e.g. ureter wall), for visibility and safety during potential clinical application. Based on both image quality and instrument diameter, the 6k pixel endoscope provided an optimal solution for miniature ureteroscopy.

Continuous-wave vs. pulsed infrared laser stimulation of the rat prostate cavernous nerves

NASA Astrophysics Data System (ADS)

Tozburun, Serhat; Cilip, Christopher M.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

2011-03-01

Optical nerve stimulation has recently been developed as an alternative to electrical nerve stimulation. However, recent studies have focused primarily on pulsed delivery of the laser radiation and at relatively low pulse rates. The objective of this study is to demonstrate faster optical stimulation of the prostate cavernous nerves using continuouswave (CW) infrared laser radiation, for potential diagnostic applications. A Thulium fiber laser (λ = 1870 nm) was used for non-contact optical stimulation of the rat prostate cavernous nerves, in vivo. Optical nerve stimulation, as measured by an intracavernous pressure (ICP) response in the penis, was achieved with the laser operating in either CW mode, or with a 5-ms pulse duration at 10, 20, 30, 40, 50, and 100 Hz. Successful optical stimulation was observed to be primarily dependent on a threshold nerve temperature (42-45 °C), not an incident fluence, as previously reported. CW optical nerve stimulation provides a significantly faster ICP response time using a laser with lower power output than pulsed stimulation. CW optical nerve stimulation may therefore represent an alternative mode of stimulation for intra-operative diagnostic applications where a rapid response is critical, such as identification of the cavernous nerves during prostate cancer surgery.

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

NASA Astrophysics Data System (ADS)

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.

Best laser for prostatectomy in the year 2013

PubMed Central

Maheshwari, Pankaj N; Joshi, Nitin; Maheshwari, Reeta P

2013-01-01

Lasers have come a long way in the management of benign prostatic hyperplasia. Over last nearly two decades, various different lasers have been utilized for prostatectomy. Neodymium: yttrium-aluminum-garnet laser that started this journey, is no longer used for prostatectomy. Holmium laser can achieve transurethral enucleation of the prostatic adenoma producing a fossa that can be compared with the fossa after Freyer's prostatectomy. Green light laser has a short learning curve, is nearly blood-less with good immediate results. Thulium laser is a faster cutting laser while diode laser is a portable laser device. Often laser prostatectomy is considered as a replacement for the standard transurethral resection of prostate (TURP). To be comparable, laser should reduce or avoid the immediate and long-term complications of TURP, especially bleeding and need for blood transfusion. It should also be safe in the ever increasing patient population on antiplatelet and anticoagulant drugs. We need to take stock of the situation and identify, which among the present day lasers has stood the test of time. A review of the literature was performed to see if any of these lasers could be called the “best laser for prostatectomy in 2013.” PMID:24082446

Pulmonary resections: cytostructural effects of different-wavelength lasers versus electrocautery.

PubMed

Scanagatta, Paolo; Pelosi, Giuseppe; Leo, Francesco; Furia, Simone; Duranti, Leonardo; Fabbri, Alessandra; Manfrini, Aldo; Villa, Antonello; Vergani, Barbara; Pastorino, Ugo

2012-01-01

There are few papers on the cytostructural effects of surgical instruments used during pulmonary resections. The aim of the present study was to evaluate the parenchymal damage caused by different surgical instruments: a new generation electrosurgical scalpel and two different-wavelength lasers. Six surgical procedures of pulmonary resection for nodules were performed using a new generation electrosurgical scalpel, a 1318 nm neodymium (Nd:YAG) laser or a 2010 nm thulium laser (two procedures for each instrument). Specimens were analyzed using optical microscopy and scansion electronic microscopy. Severe cytostructural damage was found to be present in an average of 1.25 mm in depth from the cutting surface in the patients treated using electrosurgical cautery. The depth of this zone dropped to less than 1 mm in patients treated by laser, being as small as 0.2 mm using the laser with a 2010 nm-wavelength and 0.6 mm with the 1318 nm-wavelength laser. These preliminary findings support the use of laser to perform conservative pulmonary resections (i.e., metastasectomies), since it is more likely to avoid damage to surrounding structures. Controlled randomized trials are needed to support the clinical usefulness and feasibility of new types of lasers for pulmonary resections.

Advances in laser technology and fibre-optic delivery systems in lithotripsy.

PubMed

Fried, Nathaniel M; Irby, Pierce B

2018-06-08

The flashlamp-pumped, solid-state holmium:yttrium-aluminium-garnet (YAG) laser has been the laser of choice for use in ureteroscopic lithotripsy for the past 20 years. However, although the holmium laser works well on all stone compositions and is cost-effective, this technology still has several fundamental limitations. Newer laser technologies, including the frequency-doubled, double-pulse YAG (FREDDY), erbium:YAG, femtosecond, and thulium fibre lasers, have all been explored as potential alternatives to the holmium:YAG laser for lithotripsy. Each of these laser technologies is associated with technical advantages and disadvantages, and the search continues for the next generation of laser lithotripsy systems that can provide rapid, safe, and efficient stone ablation. New fibre-optic approaches for safer and more efficient delivery of the laser energy inside the urinary tract include the use of smaller-core fibres and fibres that are tapered, spherical, detachable or hollow steel, or have muzzle brake distal fibre-optic tips. These specialty fibres might provide advantages, including improved flexibility for maximal ureteroscope deflection, reduced cross section for increased saline irrigation rates through the working channel of the ureteroscope, reduced stone retropulsion for improved stone ablation efficiency, and reduced fibre degradation and burnback for longer fibre life.

Lasers in clinical urology: state of the art and new horizons.

PubMed

Marks, Andrew J; Teichman, Joel M H

2007-06-01

We present an overview of current and emerging lasers for Urology. We begin with an overview of the Holmium:YAG laser. The Ho:YAG laser is the gold standard lithotripsy modality for endoscopic lithotripsy, and compares favorably to standard electrocautery transurethral resection of the prostate for benign prostatic hyperplasia (BPH). Available laser technologies currently being studied include the frequency doubled double-pulse Nd:Yag (FREDDY) and high-powered potassium-titanyl-phosphate (KTP) lasers. The FREDDY laser presents an affordable and safe option for intracorporeal lithotripsy, but it does not fragment all stone compositions, and does not have soft tissue applications. The high power KTP laser shows promise in the ablative treatment of BPH. Initial experiments with the Erbium:YAG laser show it has improved efficiency of lithotripsy and more precise ablative and incisional properties compared to Ho:YAG, but the lack of adequate optical fibers limits its use in Urology. Thulium:YAG fiber lasers have also demonstrated tissue ablative and incision properties comparable to Ho:YAG. Lastly, compact size, portability, and low maintenance schedules of fiber lasers may allow them to shape the way lasers are used by urologists in the future.

Numerical simulations of the optical gain of crystalline fiber doped by rare earth and transition ion

NASA Astrophysics Data System (ADS)

Daoui, A. K.; Boubir, B.; Adouane, A.; Demagh, N.; Ghoumazi, M.

2015-02-01

A fiber laser is a laser whose gain medium is a doped fiber, although lasers whose cavity is made wholly of fibers have also been called fiber lasers. The gain media in a fiber laser is usually fiber doped with rare-earth ions, such as erbium (Er), neodymium (Nd), ytterbium (Yb), thulium (Tm), or praseodymium (Pr), which is doped into the core of the optical fiber, similar to those used to transmit telecommunications signals. Fiber lasers find many applications in materials processing, including cutting, welding, drilling, and marking metal. To maximize their market penetration, it is necessary to increase their output power. In this work, we present a detailed study based on the numerical simulation using MATLAB, of one of the principal characteristics of a fiber laser doped with rare earth ions and transition ion. The gain depends on several parameters such as the length of the doped fiber, the density, the pump power, noise, etc.). The used program resolves the state equations in this context together with those governing the light propagation phenomena. The developed code can also be used to study the dynamic operating modes of a doped fiber laser.

Spectroscopy and energy transfer in lead borate glasses doubly doped with Tm3+ and Dy3+ ions

NASA Astrophysics Data System (ADS)

Górny, Agata; Sołtys, Marta; Pisarska, Joanna; Pisarski, Wojciech A.

2018-03-01

Lead borate glasses singly and doubly doped with Tm3+ and Dy3+ were prepared by traditional melt-quenching technique. The emission spectra of rare earths in studied glass systems were registered under different excitation wavelengths. The observed emission bands are located in the visible spectral region. They correspond to 1D2 → 3F4 (blue) and 1G4 → 3H6 (blue) transitions of Tm3+ as well as 4F9/2 → 6H15/2 (blue), 4F9/2 → 6H13/2 (yellow) and 4F9/2 → 6H11/2 (red) transitions of Dy3+. Moreover, the energy transfer process from Tm3+ to Dy3+ was observed. The luminescence bands originating to characteristic transitions of thulium and dysprosium ions are present on emission spectra under direct excitation of Tm3+. Luminescence lifetimes for the excited states of Tm3+ and Dy3+ ions in lead borate glass were also determined based on decay measurements. The luminescence intensities and lifetimes depend significantly on the relative concentrations of the optically active dopants.

[Bladder neck sclerosis following prostate surgery : Which therapy when?

PubMed

Rassweiler, J J; Weiss, H; Heinze, A; Elmussareh, M; Fiedler, M; Goezen, A S

2017-09-01

Secondary bladder neck sclerosis represents one of the more frequent complications following endoscopic, open, and other forms of minimally invasive prostate surgery. Therapeutic decisions depend on the type of previous intervention (e.g., radical prostatectomy, TURP, HoLEP, radiotherapy, HIFU) and on associated complications (e.g., incontinence, fistula). Primary treatment in most cases represents an endoscopic bilateral incision. No specific advantages of any type of the applied energy (i.e., mono-/bipolar HF current, cold incision, holmium/thulium YAG laser) could be documented. Adjuvant measures such as injection of corticosteroids or mitomycin C have not been helpful in clinical routine. In case of first recurrence, a transurethral monopolar or bipolar resection can usually be performed. Recently, the ablation of the scared tissue using bipolar vaporization has been recommended providing slightly better long-term results. Thereafter, surgical reconstruction is strongly recommended using an open, laparoscopic, or robot-assisted approach. Depending on the extent of the bladder neck sclerosis and the underlying prostate surgery, a Y-V/T-plasty, urethral reanastomosis, or even a radical prostatectomy with new urethravesical anastomosis should be performed. Stent implantation should be reserved for patients who are not suitable for surgery. The final palliative measure is a cystectomy with urinary diversion or a (continent) cystostomy.

Continuous-wave infrared optical nerve stimulation for potential diagnostic applications

NASA Astrophysics Data System (ADS)

Tozburun, Serhat; Cilip, Christopher M.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

2010-09-01

Optical nerve stimulation using infrared laser radiation has recently been developed as a potential alternative to electrical nerve stimulation. However, recent studies have focused primarily on pulsed delivery of the laser radiation and at relatively low pulse rates. The objective of this study is to demonstrate faster optical stimulation of the prostate cavernous nerves using continuous-wave (cw) infrared laser radiation for potential diagnostic applications. A thulium fiber laser (λ=1870 nm) is used for noncontact optical stimulation of the rat prostate cavernous nerves in vivo. Optical nerve stimulation, as measured by an intracavernous pressure (ICP) response in the penis, is achieved with the laser operating in either cw mode, or with a 5-ms pulse duration at 10, 20, 30, 40, 50, and 100 Hz. Successful optical stimulation is observed to be primarily dependent on a threshold nerve temperature (42 to 45 °C), rather than an incident fluence, as previously reported. cw optical nerve stimulation provides a significantly faster ICP response time using a lower power (and also less expensive) laser than pulsed stimulation. cw optical nerve stimulation may therefore represent an alternative mode of stimulation for intraoperative diagnostic applications where a rapid response is critical, such as identification of the cavernous nerves during prostate cancer surgery.

Low-loss, robust fusion splicing of silica to chalcogenide fiber for integrated mid-infrared laser technology development.

PubMed

Thapa, Rajesh; Gattass, Rafael R; Nguyen, Vinh; Chin, Geoff; Gibson, Dan; Kim, Woohong; Shaw, L Brandon; Sanghera, Jasbinder S

2015-11-01

We demonstrate a low-loss, repeatable, and robust splice between single-mode silica fiber and single-mode chalcogenide (CHG) fiber. These splices are particularly difficult to create because of the significant difference in the two fibers' glass transition temperatures (∼1000°C) as well as the large difference in the coefficients of thermal expansion between the fibers (∼20×10(-6)/°C). With 90% light coupled through the silica-CHG fiber splice, predominantly in the fundamental circular-symmetric mode, into the core of the CHG fiber and with 0.5 dB of splice loss measured around the wavelength of 2.5 μm, after correcting only for the Fresnel loss, the silica-CHG splice offers excellent beam quality and coupling efficiency. The tensile strength of the splice is greater than 12 kpsi, and the laser damage threshold is greater than 2 W (CW) and was limited by the available laser pump power. We also utilized this splicing technique to demonstrate 2 to 4.5 μm ultrabroadband supercontinuum generation in a monolithic all-fiber system comprising a CHG fiber and a high peak power 2 μm pulsed Raman-shifted thulium fiber laser. This is a major development toward compact form factor commercial applications of soft-glass mid-IR fibers.

Optical decoherence studies of Tm3 +:Y3Ga5O12

NASA Astrophysics Data System (ADS)

Thiel, C. W.; Sinclair, N.; Tittel, W.; Cone, R. L.

2014-12-01

Decoherence of the 795 nm 3H6 to 3H4 transition in 1 %Tm3 +:Y3Ga5O12 (Tm:YGG) is studied at temperatures as low as 1.2 K. The temperature, magnetic field, frequency, and time scale (spectral diffusion) dependence of the optical coherence lifetime is measured. Our results show that the coherence lifetime is impacted less by spectral diffusion than other known thulium-doped materials. Photon echo excitation and spectral hole burning methods reveal uniform decoherence properties and the possibility to produce full transparency for persistent spectral holes across the entire 56 GHz inhomogeneous bandwidth of the optical transition. Temperature-dependent decoherence is well described by elastic Raman scattering of phonons with an additional weaker component that may arise from a low density of glass-like dynamic disorder modes (two-level systems). Analysis of the observed behavior suggests that an optical coherence lifetime approaching 1 ms may be possible in this system at temperatures below 1 K for crystals grown with optimized properties. Overall, we find that Tm:YGG has superior decoherence properties compared to other Tm-doped crystals and is a promising candidate for applications that rely on long coherence lifetimes, such as optical quantum memories and photonic signal processing.

A compact, inexpensive infrared laser system for continuous-wave optical stimulation of the rat prostate cavernous nerves

NASA Astrophysics Data System (ADS)

Perkins, William C.; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

2014-03-01

Optical nerve stimulation (ONS) has been commonly performed in the laboratory using high-power, pulsed, infrared (IR) lasers including Holmium:YAG, diode, and Thulium fiber lasers. However, the relatively high cost of these lasers in comparison with conventional electrical nerve stimulation (ENS) equipment may represent a significant barrier to widespread adoption of ONS. Optical stimulation of the prostate cavernous nerves (CN's) has recently been reported using lower cost, continuous-wave (CW), all-fiber-based diode lasers. This preliminary study describes further miniaturization and cost reduction of the ONS system in the form of a compact, lightweight, cordless, and inexpensive IR laser. A 140-mW, 1560-nm diode laser was integrated with a green aiming beam and delivery optics into a compact ONS system. Surface and subsurface ONS was performed in a total of 5 rats, in vivo, with measurement of an intracavernous pressure (ICP) response during CW laser irradiation for 30 s with a spot diameter of 0.7 mm. Short-term, CW ONS of the prostate CN's is feasible using a compact, inexpensive, batterypowered IR laser diode system. This ONS system may represent an alternative to ENS for laboratory studies, and with further development, a handheld option for ONS in the clinic to identify and preserve the CN's during prostate cancer surgery.

Optimization of a novel Tm fiber laser lithotripter in terms of stone ablation efficiency and retropulsion reduction

NASA Astrophysics Data System (ADS)

Yaroslavsky, Ilya; Vinnichenko, Victoria; McNeill, Tyler; Novoseltseva, Anna; Perchuk, Igor; Vybornov, Alexander; Altshuler, Gregory; Gapontsev, Valentin

2018-02-01

Recently, a Thulium (Tm) fiber laser operating at a wavelength of 1940 nm and peak power up to 500 W has been introduced as a promising energy source for laser lithotripsy. Direct comparative studies have demonstrated considerable advantages of Tm fiber laser over the current industry-standard 2100 nm Holmium:YAG (Ho:YAG) device in terms of ablation rate and retropulsion effects. In this work, we investigated avenues of further improving stone ablation efficiency and reducing retropulsion. Specifically, the roles of temporal pulse structure and fiber tip preparation were studied in detail. Experiments were conducted on Bego stone phantoms in an aqueous environment using a computerized 2D stage for controlled scanning of the fiber over the stone surface. High-resolution 3D-enabled optical microscopy was employed to assess both fiber tip damage and stone ablation rate. Retropulsion effects were quantified using a high-speed video camera. Fiber burn back was evaluated as well. Fiber performance could be preserved during prolonged (up to 15 min) procedures when the fiber tip was adequately prepared. Furthermore, the results were compared with available literature for similar experiments performed with the Ho:YAG laser. The data obtained provide an important foundation for optimizing clinical performance of Tm fiber systems for lithotripsy.

Cutting and skin-ablative properties of pulsed mid-infrared laser surgery.

PubMed

Kaufmann, R; Hartmann, A; Hibst, R

1994-02-01

Pulsed mid-infrared lasers allow a precise removal of soft tissues with only minimal thermal damage. To study the potential dermatosurgical usefulness of currently available systems at different wavelengths (2010-nm Thulium:YAG laser, 2100-nm Holmium:YAG laser, 2790-nm Erbium:YSGG laser, and 2940-nm Erbium:YAG laser) in vivo on pig skin. Immediate effects and wound healing of superficial laser-abrasions and incisions were compared with those of identical control lesions produced by dermabrasion, scalpel incisions, or laser surgery performed by a 1060-nm Nd:YAG and a 1060-nm CO2 laser (continuous and superpulsed mode). Best efficiency and least thermal injury was found for the pulsed Erbium:YAG laser, leading to ablative and incisional lesions comparable to those obtained by dermabrasion or superficial scalpel incisions, respectively. In contrast to other mid-infrared lasers tested, the 2940-nm Erbium:YAG laser thus provides a potential instrument for future applications in skin surgery, especially when aiming at a careful ablative removal of delicate superficial lesions with maximum sparing of adjacent tissue structures. However, in the purely incisional application mode pulsed mid-infrared lasers, though of potential usefulness in microsurgical indications (eg, surgery of the cornea), do not offer a suggestive alternative to simple scalpel surgery of the skin.

Ultrasmall lanthanide-doped nanoparticles as multimodal platforms

NASA Astrophysics Data System (ADS)

Yust, Brian G.; Pedraza, Francisco J.; Sardar, Dhiraj K.

2014-03-01

Recently, there has been a great amount of interest in nanoparticles which are able to provide a platform with high contrast for multiple imaging modalities in order to advance the tools available to biomedical researchers and physicians. However, many nanoparticles do not have ideal properties to provide high contrast in different imaging modes. In order to address this, ultrasmall lanthanide doped oxide and fluoride nanoparticles with strong NIR to NIR upconversion fluorescence and a strong magnetic response for magnetic resonance imaging (MRI) have been developed. Specifically, these nanoparticles incorporate gadolinium, dysprosium, or a combination of both into the nano-crystalline host to achieve the magnetic properties. Thulium, erbium, and neodymium codopants provide the strong NIR absorption and emission lines that allow for deeper tissue imaging since near infrared light is not strongly absorbed or scattered by most tissues within this region. This also leads to better image quality and lower necessary excitation intensities. As a part of the one pot synthesis, these nanoparticles are coated with peg, pmao, or d-glucuronic acid to make them water soluble, biocompatible, and bioconjugable due to the available carboxyl or amine groups. Here, the synthesis, morphological characterization, magnetic response, NIR emission, and the quantum yield will be discussed. Cytotoxicity tested through cell viability at varying concentrations of nanoparticles in growth media will also be discussed.

Deficiency of the bulk spin Hall effect model for spin-orbit torques in magnetic-insulator/heavy-metal heterostructures

NASA Astrophysics Data System (ADS)

Li, Junxue; Yu, Guoqiang; Tang, Chi; Liu, Yizhou; Shi, Zhong; Liu, Yawen; Navabi, Aryan; Aldosary, Mohammed; Shao, Qiming; Wang, Kang L.; Lake, Roger; Shi, Jing

2017-06-01

Electrical currents in a magnetic-insulator/heavy-metal heterostructure can induce two simultaneous effects, namely, spin Hall magnetoresistance (SMR) on the heavy-metal side and spin-orbit torques (SOTs) on the magnetic-insulator side. Within the framework of a pure spin current model based on the bulk spin Hall effect (SHE), the ratio of the spin Hall-induced anomalous Hall effect (SH-AHE) to SMR should be equal to the ratio of the fieldlike torque (FLT) to the dampinglike torque (DLT). We perform a quantitative study of SMR, SH-AHE, and SOTs in a series of thulium iron garnet/platinum or T m3F e5O12/Pt heterostructures with different T m3F e5O12 thicknesses, where T m3F e5O12 is a ferrimagnetic insulator with perpendicular magnetic anisotropy. We find the ratio between the measured effective fields of FLT and DLT is at least two times larger than the ratio of the SH-AHE to SMR. In addition, the bulk SHE model grossly underestimates the spin-torque efficiency of FLT. Our results reveal deficiencies of the bulk SHE model and also address the importance of interfacial effects such as the Rashba and magnetic proximity effects in magnetic-insulator/heavy-metal heterostructures.

The characterization of neural tissue ablation rate and corresponding heat affected zone of a 2 micron Tm3+ doped fiber laser(Conference Presentation)

NASA Astrophysics Data System (ADS)

Marques, Andrew J.; Jivraj, Jamil; Reyes, Robnier; Ramjist, Joel; Gu, Xijia J.; Yang, Victor X. D.

2017-02-01

Tissue removal using electrocautery is standard practice in neurosurgery since tissue can be cut and cauterized simultaneously. Thermally mediated tissue ablation using lasers can potentially possess the same benefits but with increased precision. However, given the critical nature of the spine, brain, and nerves, the effects of direct photo-thermal interaction on neural tissue needs to be known, yielding not only high precision of tissue removal but also increased control of peripheral heat damage. The proposed use of lasers as a neurosurgical tool requires that a common ground is found between ablation rates and resulting peripheral heat damage. Most surgical laser systems rely on the conversion of light energy into heat resulting in both desirable and undesirable thermal damage to the targeted tissue. Classifying the distribution of thermal energy in neural tissue, and thus characterizing the extent of undesirable thermal damage, can prove to be exceptionally challenging considering its highly inhomogenous composition when compared to other tissues such as muscle and bone. Here we present the characterization of neural tissue ablation rate and heat affected zone of a 1.94 micron thulium doped fiber laser for neural tissue ablation. In-Vivo ablation of porcine cerebral cortex is performed. Ablation volumes are studied in association with laser parameters. Histological samples are taken and examined to characterize the extent of peripheral heat damage.

An 8 cm long holmium-doped fiber saturable absorber for Q-switched fiber laser generation at 2-μm region

NASA Astrophysics Data System (ADS)

Rahman, M. F. A.; Dhar, A.; Das, S.; Dutta, D.; Paul, M. C.; Rusdi, M. F. M.; Latiff, A. A.; Dimyati, K.; Harun, S. W.

2018-07-01

We demonstrate a Q-switched all-fiber laser operating at 2-μm region by adding a piece of 8 cm long holmium doped fiber (HDF) as a fiber saturable absorber (SA) in Thulium doped fiber laser (TDFL) ring cavity. Doping of Ho ions into yttria-alumina silica glass was done through conventional Modified Chemical Vapor Deposition (MCVD) technique in conjunction with solution doping process. The fabricated HDF has a linear absorption of 3 dB with a core diameter and a numerical aperture of 10 μm and 0.18, respectively. A self-started Q-switching operation begins at 418 mW pump level and continually dominant until 564 mW pump level. As the pump power increases, stable pulse train presence from 30.61 kHz to 38.89 kHz while the pulse width reduces from 3.18 μs to 2.27 μs. Both maximum output power and maximum peak power are obtained at 5.05 mW and 57.2 mW, respectively, while the maximum pulse energy is calculated to be 129 nJ. The signal-to-noise ratio (SNR) of the fundamental frequency is 50 dB. Our work may contribute to the discovery of stable, robust, and economic SA for pulse fiber laser generation at 2-μm region.

Light-assisted drying (LAD) of small volume biologics: a comparison of two IR light sources

NASA Astrophysics Data System (ADS)

Young, Madison A.; Van Vorst, Matthew; Elliott, Gloria D.; Trammell, Susan R.

2016-03-01

Protein therapeutics have been developed to treat diseases ranging from arthritis and psoriasis to cancer. A challenge in the development of protein-based drugs is maintaining the protein in the folded state during processing and storage. We are developing a novel processing method, light-assisted drying (LAD), to dehydrate proteins suspended in a sugar (trehalose) solution for storage at supra-zero temperatures. Our technique selectively heats the water in small volume samples using near-IR light to speed dehydration which prevents sugar crystallization that can damage embedded proteins. In this study, we compare the end moisture content (EMC) as a function of processing time of samples dried with two different light sources, Nd:YAG (1064 nm) and Thulium fiber (1850 nm) lasers. EMC is the ratio of water to dry weight in a sample and the lower the EMC the higher the possible storage temperature. LAD with the 1064 and 1850 nm lasers yielded 78% and 65% lower EMC, respectively, than standard air-drying. After 40 minutes of LAD with 1064 and 1850 nm sources, EMCs of 0.27+/-.27 and 0.15+/-.05 gH2O/gDryWeight were reached, which are near the desired value of 0.10 gH2O/gDryWeight that enables storage in a glassy state without refrigeration. LAD is a promising new technique for the preparation of biologics for anhydrous preservation.

High-pulse energy Q-switched Tm3+:YAG laser for nonlinear frequency conversion to the mid-IR

NASA Astrophysics Data System (ADS)

Stöppler, Georg; Kieleck, Christelle; Eichhorn, Marc

2010-10-01

For some medical fields in laser surgery and as a pump source for nonlinear materials to generate mid-IR radiation, e.g. for countermeasure applications, it is very useful to have a solid-state laser with high pulse energy at 2 μm. The rare earth ion Thulium offers a cross relaxation and can thus be directly diode pumped with common laser diodes around 800 nm for an efficient pumping. However, it was not considered for high pulse energy operation due to the high saturation fluence of around 62 J/cm2 at 2 μm. A limiting factor has always been the damage threshold of the optical elements inside the cavity. One of the reasons is the strong thermal lens of YAG, which affects a change of the beam radius inside the resonator and additionally degrades the beam quality with increasing pump power. Using a new pump geometry of the Tm3+:YAG laser system, it is now possible to reach pulse energies > 13 mJ at a diffraction limited beam quality of M2 < 1.1. The Q-switched Tm3+:YAG laser system uses an AOM operating at 100 Hz and will be described in detail. Due to the high pulse energy and very good beam quality, this laser is very interesting for nonlinear parametric frequency conversion.

Comparison of three pulsed infrared lasers for optical stimulation of the rat prostate cavernous nerves

NASA Astrophysics Data System (ADS)

Stahl, Charlotte S. D.; Tozburun, Serhat; Hutchens, Thomas C.; Lagoda, Gwen A.; Burnett, Arthur L.; Keller, Matthew D.; Fried, Nathaniel M.

2013-03-01

Optical nerve stimulation (ONS) is being explored for identification and preservation of the cavernous nerves (CN), responsible for erectile function, during prostate cancer surgery. This study compares three pulsed infrared lasers to determine whether differences in spectral linewidth and/or temporal pulse profile influence successful ONS of CN. Infrared laser radiation from the Capella diode laser (1873 nm, 5 ms, 10 Hz), Thulium fiber laser (TFL) (1873 nm, 5 ms, 10 Hz), and solid-state Holmium:YAG laser (2120 nm, 200 μs, 5 Hz) were transmitted through 400-μm-corediameter optical fibers, producing a 1-mm-diameter-spot on the nerve surface. Successful ONS was judged by an intracavernous pressure (ICP) response in the penis (n =10 rats) during a total stimulation time of 30 s. The narrow linewidth TFL (Δλ 0.5 nm) and broad linewidth Capella laser (Δλ 12 nm) performed similarly, producing ICP responses with a threshold radiant exposure of 0.45 J/cm2, and ICP response times of 12-17 s, while the Holmium laser stimulated at 0.59 J/cm2, and ICP response times of about 14-28 s. All three lasers demonstrated successful ONS of CN. ICP response time was dependent on the rate of energy deposition into the CN, rather than linewidth or temporal pulse profile.

Development of Ceramic Solid-State Laser Host Material

NASA Technical Reports Server (NTRS)

Prasad, Narasimha S.; Trivedi, Sudhir; Kutcher, Susan; Wang, Chen-Chia; Kim, Joo-Soo; Hommerich, Uwe; Shukla, Vijay; Sadangi, Rajendra

2009-01-01

Polycrystalline ceramic laser materials are gaining importance in the development of novel diode-pumped solid-state lasers. Compared to single-crystals, ceramic laser materials offer advantages in terms of ease of fabrication, shape, size, and control of dopant concentrations. Recently, we have developed Neodymium doped Yttria (Nd:Y2O3) as a solid-state ceramic laser material. A scalable production method was utilized to make spherical non agglomerated and monodisperse metastable ceramic powders of compositions that were used to fabricate polycrystalline ceramic material components. This processing technique allowed for higher doping concentrations without the segregation problems that are normally encountered in single crystalline growth. We have successfully fabricated undoped and Neodymium doped Yttria material up to 2" in diameter, Ytterbium doped Yttria, and erbium doped Yttria. We are also in the process of developing other sesquioxides such as scandium Oxide (Sc2O3) and Lutesium Oxide (Lu2O3) doped with Ytterbium, erbium and thulium dopants. In this paper, we present our initial results on the material, optical, and spectroscopic properties of the doped and undoped sesquioxide materials. Polycrystalline ceramic lasers have enormous potential applications including remote sensing, chem.-bio detection, and space exploration research. It is also potentially much less expensive to produce ceramic laser materials compared to their single crystalline counterparts because of the shorter fabrication time and the potential for mass production in large sizes.

The role of lasers in modern urology.

PubMed

Dołowy, Łukasz; Krajewski, Wojciech; Dembowski, Janusz; Zdrojowy, Romuald; Kołodziej, Anna

2015-01-01

The functioning of modern urological departments and the high level of service they provide is possible through, among other things, the use of modern laser techniques. Open operations have been replaced by minimally invasive procedures, and classical surgical tools by advanced lasers. The search for new applications with lasers began as technology developed. Among many devices available, holmium, diode and thulium lasers are currently the most popular. Depending on the wavelength, the absorption by water and hemoglobin and the depth of penetration, lasers can be used for coagulation, vaporization and enucleation. In many centres, after all the possibilities of pharmacological treatment have been exhausted, lasers are used as the primary treatment for patients with benign prostatic hyperplasia, with therapeutic results that are better than those obtained through open or endoscopic operations. The use of lasers in the treatment of urolithiasis, urinary strictures and bladder tumours has made treatment of older patients with multiple comorbidities safe, without further necessity to modify the anticoagulant drug treatment. Laser procedures are additionally less invasive, reduce hospitalization time and enable a shorter bladder catheterization time, sometimes even eliminating the need for bladder catherterization completely. Such procedures are also characterized by more stable outcomes and a lower number of reoperations. There are also indications that with the increased competition among laser manufacturers, decreased purchase and maintenance costs, and increased operational safety, laser equipment will become mandatory and indispensable asset in all urology wards.

Bilayer insulator tunnel barriers for graphene-based vertical hot-electron transistors

NASA Astrophysics Data System (ADS)

Vaziri, S.; Belete, M.; Dentoni Litta, E.; Smith, A. D.; Lupina, G.; Lemme, M. C.; Östling, M.

2015-07-01

Vertical graphene-based device concepts that rely on quantum mechanical tunneling are intensely being discussed in the literature for applications in electronics and optoelectronics. In this work, the carrier transport mechanisms in semiconductor-insulator-graphene (SIG) capacitors are investigated with respect to their suitability as electron emitters in vertical graphene base transistors (GBTs). Several dielectric materials as tunnel barriers are compared, including dielectric double layers. Using bilayer dielectrics, we experimentally demonstrate significant improvements in the electron injection current by promoting Fowler-Nordheim tunneling (FNT) and step tunneling (ST) while suppressing defect mediated carrier transport. High injected tunneling current densities approaching 103 A cm-2 (limited by series resistance), and excellent current-voltage nonlinearity and asymmetry are achieved using a 1 nm thick high quality dielectric, thulium silicate (TmSiO), as the first insulator layer, and titanium dioxide (TiO2) as a high electron affinity second layer insulator. We also confirm the feasibility and effectiveness of our approach in a full GBT structure which shows dramatic improvement in the collector on-state current density with respect to the previously reported GBTs. The device design and the fabrication scheme have been selected with future CMOS process compatibility in mind. This work proposes a bilayer tunnel barrier approach as a promising candidate to be used in high performance vertical graphene-based tunneling devices.

Thermal lensing effects in rod-based Tm3+: YLF amplifiers versus pump and cooling conditions

NASA Astrophysics Data System (ADS)

Jolly, A.; Vidal, S.; Boullet, J.

2018-06-01

We report on a comprehensive study of the thermal-lensing penalties in rod-based, end-pumped amplifiers made of thulium-doped YLF. Aiming to optimize the beam quality under optimized pump and cooling conditions, this applies to the definition of highly efficient laser designs with operation up to the saturation of the gain. Single-pass and double-pass pump schemes are benchmarked by means of an innovative modeling process, to determine the appropriate rod’s length and the complete set of input data which determines the spatial transfer function of a given rod. This is done in the form of an equivalent, pump-dependent, thick GRIN lens. The characteristics of this highly astigmatic and basically divergent lens are computed thanks to complementary 3D-FEM thermo-mechanical modeling. To benchmark the different contributors to natural thermal-lensing phenomena, we refer to the situation of uniform side-cooling. The computational results are parameterized in a broad range of operating conditions. Then we suggest non-uniform side-cooling, as a possible option of interest for cancelling the astigmatism. The development of YLF-based amplifiers of a new generation taking advantage of a highly stable and easily controllable beam quality, either using rod-based or slab-based architectures, will be part of the potential applications of this fairly generic modeling approach.

1.319 μm excited intense 800 nm frequency upconversion emission in Tm{sup 3+}-doped fluorogermanate glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gouveia-Neto, A. S.; Vermelho, M. V. D.; Gouveia, E. A.

2015-11-23

Generation of near-infrared light within the first biological optical window via frequency upconversion in Tm{sup 3+}-doped PbGeO{sub 3}-PbF{sub 2}-CdF{sub 2} glass excited within the second biological window at 1.319 μm is reported. The upconversion emission at 800 nm is the sole light signal observed in the entire ultraviolet-visible-near-infrared spectral region making it possible obtaining high contrast imaging. The dependence of the 800 nm signal upon the sample temperature was investigated and results showed an increase by a factor of ×2.5 in the 30–280 °C range. Generation of detectable 690 nm for temperatures above 100 °C in addition to the intense 800 nm main signal was also observed.more » The proposed excitation mechanism for the 800 nm thulium emitting level is assigned to a multiphonon-assisted excitation from the ground-state {sup 3}H{sub 6} to the {sup 3}H{sub 5} excited-state level, a rapid relaxation to the {sup 3}F{sub 4} level and followed by an excited-state absorption of the pump photons mediated by multiphonons connecting the {sup 3}F{sub 4} level to the {sup 3}H{sub 4} emitting level.« less

Myocardial expression of the vascular endothelial growth factor (VEGF) after endocardial laser revascularization (ELR)

NASA Astrophysics Data System (ADS)

Rommerscheid, Jan; Theisen, Dirk; Schmuecker, G.; Brinkmann, Ralf; Broll, R.

2001-10-01

Background. Endocardial laser revascularization (ELR) is a new technique to treat patients with severe coronary artery disease (CAD) in a percutaneous approach. The results show a significant improvement of symptoms, but the mechanism of action is still unknown. One main theory is the angiogenesis for which Vascular Endothelial Growth Factor (VEGF) is the keypromotor. We investigated immunohistochemically the VEGF-expression after ELR in porcine hearts over a timeperiod of four weeks. Methods. ELR was performed with a single-pulse Thulium:YAG laser. 15 pigs were treated with ELR and the hearts were harvested at five timeperiods: directly (group I), 3 days (group II), 1 week (group III), 2 weeks (group IV) and 4 weeks (group V) after ELR. Each group consisted of three pigs. Immunohistochemically the VEGF-expression was assessed by staining with a polyclonal antibody against VEGF and cellcounting using an expression index (VEGF-EI) Results. A maximum of VEGF-expression was found three days (group II) after ELR with a VEGF-EI of 97%. At 1 week (group III) the VEGF-EI was similar high with 93%. Along the timecourse the index decreased to 22% at 4 weeks (groupV). Conclusions. Our findings show that ELR leads to an local upregulation of VEGF around the channels. The resulting angiogenesis could be the mechanism for the relief of angina.

S-band optical amplification by an internally generated pump in thulium ytterbium codoped fiber.

PubMed

Chang, Jun; Wang, Qing-Pu; Zhang, Xingyu; Liu, Zhejin; Liu, Zhaojun; Peng, Gang-Ding

2005-05-30

We propose a novel scheme in which Yb3+ codoping and a laser cavity are introduced in Tm3+ doped fiber to achieve efficient S-band optical amplification with a 980 nm pump source. This scheme makes it possible for conventional 980 nm pump sources for Er3+ doped fiber amplifiers to be used for S-band Tm3+ doped fiber amplifiers (TDFAs). By introducing a laser cavity into an amplifier, an internally generated pump from Yb3+ at a desirable wavelength for pumping Tm3+ could be produced. We establish and analyze, for the first time to our knowledge, a new theoretical model that takes into consideration both the internal lasing operation inside the optical amplification process and the energy transfer between the Tm3+ and the Yb3+ ions in TDFAs. Various situations such as Tm3+ doping concentration and cavity reflectivity have been investigated. The results show that high optical gain and high pump efficiency can be achieved by use of 980 nm sources. With a laser cavity of 1050 nm in Tm3+ and Yb3+ codoped fiber, for example, it is possible to achieve high optical gain of greater than 20 dB, a noise figure of approximately 5 dB in the wavelength range from 1450 to 1480 nm with a 0.3 W power at 980 nm pump source.

Double-Wall Carbon Nanotube Hybrid Mode-Locker in Tm-doped Fibre Laser: A Novel Mechanism for Robust Bound-State Solitons Generation

NASA Astrophysics Data System (ADS)

Chernysheva, Maria; Bednyakova, Anastasia; Al Araimi, Mohammed; Howe, Richard C. T.; Hu, Guohua; Hasan, Tawfique; Gambetta, Alessio; Galzerano, Gianluca; Rümmeli, Mark; Rozhin, Aleksey

2017-03-01

The complex nonlinear dynamics of mode-locked fibre lasers, including a broad variety of dissipative structures and self-organization effects, have drawn significant research interest. Around the 2 μm band, conventional saturable absorbers (SAs) possess small modulation depth and slow relaxation time and, therefore, are incapable of ensuring complex inter-pulse dynamics and bound-state soliton generation. We present observation of multi-soliton complex generation in mode-locked thulium (Tm)-doped fibre laser, using double-wall carbon nanotubes (DWNT-SA) and nonlinear polarisation evolution (NPE). The rigid structure of DWNTs ensures high modulation depth (64%), fast relaxation (1.25 ps) and high thermal damage threshold. This enables formation of 560-fs soliton pulses; two-soliton bound-state with 560 fs pulse duration and 1.37 ps separation; and singlet+doublet soliton structures with 1.8 ps duration and 6 ps separation. Numerical simulations based on the vectorial nonlinear Schr¨odinger equation demonstrate a transition from single-pulse to two-soliton bound-states generation. The results imply that DWNTs are an excellent SA for the formation of steady single- and multi-soliton structures around 2 μm region, which could not be supported by single-wall carbon nanotubes (SWNTs). The combination of the potential bandwidth resource around 2 μm with the soliton molecule concept for encoding two bits of data per clock period opens exciting opportunities for data-carrying capacity enhancement.

Fiber optic suctioning of urinary stone phantoms during laser lithotripsy

NASA Astrophysics Data System (ADS)

Blackmon, Richard L.; Case, Jason R.; Trammell, Susan R.; Irby, Pierce B.; Fried, Nathaniel M.

2013-03-01

Fiber optic attraction of urinary stones during laser lithotripsy has been previously observed, and this phenomenon may potentially be exploited to pull stones inside the urinary tract without mechanical grasping tools, thus saving the urologist valuable time and space in the ureteroscope's single working channel. In this study, Thulium fiber laser (TFL) high-pulse-rate/low-pulse-energy operation and Holmium:YAG low-pulse-rate/high-pulse-energy operation are compared for fiber optic "suctioning" of Plaster-of-Paris stone phantoms. A TFL with wavelength of 1908 nm, pulse energy of 35 mJ, pulse duration of 500 μs, and pulse rate of 10-350 Hz, and Holmium laser with wavelength of 2120 nm, pulse energy of 35-360 mJ, pulse duration of 300 μs, and pulse rate of 20 Hz were tested using 270-μm-core fibers. A peak "pull" speed of 2.5 mm/s was measured for both TFL (35 mJ and 150-250 Hz) and Holmium laser (210 mJ and 20 Hz). Particle image velocimetry and thermal imaging were used to track water flow for all parameters. Fiber optic suctioning of urinary stone phantoms is feasible for both lasers. However, TFL operation at high-pulse-rates/low-pulse-energies provides faster, smoother stone pulling than Holmium operation at low-pulserates/ high-pulse-energies. After further study, this method may be used to manipulate urinary stones in the clinic.

Enhancement of lanthanide evaporation by complexation: dysprosium tri-iodide mixed with indium iodide and thulium tri-iodide mixed with thallium iodide.

PubMed

Curry, J J; Estupiñán, E G; Henins, A; Lapatovich, W P; Shastri, S D; Hardis, J E

2013-09-28

The vapors in equilibrium with condensates of DyI3, DyI3/InI, TmI3, and TmI3/TlI were observed over the temperature range from 900 K to 1400 K using x-ray induced fluorescence. The total densities of each element (Dy, Tm, In, Tl, and I) in the vapor, summed over all atomic and molecular species, were determined. Dramatic enhancements in the total vapor densities of Dy and Tm were observed in the vapors over DyI3/InI and TmI3/TlI as compared to the vapors over pure DyI3 and pure TmI3, respectively. An enhancement factor exceeding 10 was observed for Dy at T ≈ 1020 K, decreasing to 0 at T ≈ 1250 K. An enhancement factor exceeding 20 was observed for Tm at T ≈ 1040 K, decreasing to 0 at T ≈ 1300 K. Such enhancements are expected from the formation of the vapor-phase hetero-complexes DyInI4 and TmTlI4. Numerical simulations of the thermo-chemical equilibrium suggest the importance of additional complexes in liquid phases. A description of the measurement technique is given. Improvements in the absolute calibration lead to an approximately 40% correction to previously reported preliminary results [J. J. Curry et al., Chem. Phys. Lett. 507, 52 (2011); Appl. Phys. Lett. 100, 083505 (2012)].

The effect of core and lanthanide ion dopants in sodium fluoride-based nanocrystals on phagocytic activity of human blood leukocytes

NASA Astrophysics Data System (ADS)

Sojka, Bartlomiej; Liskova, Aurelia; Kuricova, Miroslava; Banski, Mateusz; Misiewicz, Jan; Dusinska, Maria; Horvathova, Mira; Ilavska, Silvia; Szabova, Michaela; Rollerova, Eva; Podhorodecki, Artur; Tulinska, Jana

2017-02-01

Sodium fluoride-based β-NaLnF4 nanoparticles (NPs) doped with lanthanide ions are promising materials for application as luminescent markers in bio-imaging. In this work, the effect of NPs doped with yttrium (Y), gadolinium (Gd), europium (Eu), thulium (Tm), ytterbium (Yb) and terbium (Tb) ions on phagocytic activity of monocytes and granulocytes and the respiratory burst was examined. The surface functionalization of <10-nm NPs was performed according to our variation of patent pending ligand exchange method that resulted in meso-2,3-dimercaptosuccinic acid (DMSA) molecules on their surface. Y-core-based NCs were doped with Eu ions, which enabled them to be excited with UV light wavelengths. Cultures of human peripheral blood ( n = 8) were in vitro treated with five different concentrations of eight NPs for 24 h. In summary, neither type of nanoparticles is found toxic with respect to conducted test; however, some cause toxic effects (they have statistically significant deviations compared to reference) in some selected doses tested. Both core types of NPs (Y-core and Gd-core) impaired the phagocytic activity of monocytes the strongest, having minimal or none whatsoever influence on granulocytes and respiratory burst of phagocytic cells. The lowest toxicity was observed in Gd-core, Yb, Tm dopants and near-infrared nanoparticles. Clear dose-dependent effect of NPs on phagocytic activity of leukocytes and respiratory burst of cells was observed for limited number of samples.

Light and laser treatment modalities for disseminated superficial actinic porokeratosis: a systematic review.

PubMed

Aird, Gregory A; Sitenga, Jenna L; Nguyen, Austin Huy; Vaudreuil, Adam; Huerter, Christopher J

2017-05-01

Treatment of disseminated superficial actinic porokeratosis (DSAP) is poorly standardized. The present review seeks to comprehensively discuss the potential for laser and light modalities in the treatment of DSAP. A systematic review of light and laser treatment modalities was conducted to include 26 cases of patients with DSAP. Systematic review resulted in 14 articles to be included. Photodynamic therapy (PDT) overall was the least successful treatment modality, with clinical improvement seen in a minority of patients (MAL-PDT: N = 9 patients, 33.3% showed improvement; ALA-PDT: N = 3 patients, 0% improvement; hypericin-PDT: N = 2 patients, 0% improvement) after numerous post-procedural side effects of hyperpigmentation, inflammation, erythema, and discomfort. Overall, in the available reports, PDT demonstrates poor outcomes with greater incidence of side effects. The response rates of DSAP lesions treated with lasers were as follows: (Q-switched ruby lasers: N = 2, 100%; CO 2 laser: N = 1, 100%; PDT and CO 2 combination therapy: N = 2, 0-50%; erbium and neodymium YAG lasers: N = 2, 100%; fractional 1927-nm thulium fiber lasers: N = 2, 100%; Grenz rays: N = 1, 100%; and fractional photothermolysis: N = 2, 100%). The side effects of laser therapy were minimal and included mild erythema, slight hyperpigmentation, and moderate edema. Laser therapy is a promising treatment option for DSAP with an excellent side effect profile. However, higher power studies are required to determine optimal guidelines for laser treatment of DSAP.

Comparison of lasers used in stapedotomy using specialized visualization techniques for mechanical and thermal effects in an inner ear model

NASA Astrophysics Data System (ADS)

Kamalski, Digna M. A.; Verdaasdonk, Rudolf M.; de Boorder, Tjeerd; Grolman, Wilko

2011-03-01

The outcome of stapedotomy depends on several surgical steps. Using laser light, the ossicular chain can be handled and the oval window can be punctured with a non-touch method. Various lasers are being used or considered, however, it is not clear which settings and characteristics will contribute to optimal or adverse effects (vestibule damage and loss hearing frequencies). Using a unique high speed thermal imaging setup based on Schlieren techniques, the mechanical and thermal effects during laser stapedotomy were studied in an inner ear model consisting of human, fresh frozen stapes positioned on a liquid filled cavity in a gel cast. The cw KTP (532 nm), cw CO2 (10.6 μm), cw Thulium (2.0 μm), pulsed Er,Cr;YSGG (2.78 μm) coupled to special fiber delivery systems were applied at typical clinical settings for comparison. The imaging techniques provided a good insight in the extent of heat conduction beneath the footplate and (explosive) vapour formation on both sides. For the pulsed laser modes, explosive vapour expansion can to be controlled with optimized pulse energies while for continuous wave lasers the thermal effects can be controlled with the pulse length and repetition rate. The fluence at the tip of the delivery system and the distance to the footplate has a major impact on the ablation effect. The pulsed IR lasers with fiber delivery show to be promising for a controlled stapedotomy.

The role of lasers in modern urology

PubMed Central

Dołowy, Łukasz; Dembowski, Janusz; Zdrojowy, Romuald; Kołodziej, Anna

2015-01-01

Introduction The functioning of modern urological departments and the high level of service they provide is possible through, among other things, the use of modern laser techniques. Material and methods Open operations have been replaced by minimally invasive procedures, and classical surgical tools by advanced lasers. The search for new applications with lasers began as technology developed. Among many devices available, holmium, diode and thulium lasers are currently the most popular. Results Depending on the wavelength, the absorption by water and hemoglobin and the depth of penetration, lasers can be used for coagulation, vaporization and enucleation. In many centres, after all the possibilities of pharmacological treatment have been exhausted, lasers are used as the primary treatment for patients with benign prostatic hyperplasia, with therapeutic results that are better than those obtained through open or endoscopic operations. The use of lasers in the treatment of urolithiasis, urinary strictures and bladder tumours has made treatment of older patients with multiple comorbidities safe, without further necessity to modify the anticoagulant drug treatment. Laser procedures are additionally less invasive, reduce hospitalization time and enable a shorter bladder catheterization time, sometimes even eliminating the need for bladder catherterization completely. Such procedures are also characterized by more stable outcomes and a lower number of reoperations. Conclusions There are also indications that with the increased competition among laser manufacturers, decreased purchase and maintenance costs, and increased operational safety, laser equipment will become mandatory and indispensable asset in all urology wards. PMID:26251737

Strategic Materials in the Automobile: A Comprehensive Assessment of Strategic and Minor Metals Use in Passenger Cars and Light Trucks.

PubMed

Field, Frank R; Wallington, Timothy J; Everson, Mark; Kirchain, Randolph E

2017-12-19

A comprehensive component-level assessment of several strategic and minor metals (SaMMs), including copper, manganese, magnesium, nickel, tin, niobium, light rare earth elements (LREEs; lanthanum, cerium, praseodymium, neodymium, promethium, and samarium), cobalt, silver, tungsten, heavy rare earth elements (yttrium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium), and gold, use in the 2013 model year Ford Fiesta, Focus, Fusion, and F-150 is presented. Representative material contents in cars and light-duty trucks are estimated using comprehensive, component-level data reported by suppliers. Statistical methods are used to accommodate possible errors within the database and provide estimate bounds. Results indicate that there is a high degree of variability in SaMM use and that SaMMs are concentrated in electrical, drivetrain, and suspension subsystems. Results suggest that trucks contain greater amounts of aluminum, nickel, niobium, and silver and significantly greater amounts of magnesium, manganese, gold, and LREEs. We find tin and tungsten use in automobiles to be 3-5 times higher than reported by previous studies which have focused on automotive electronics. Automotive use of strategic and minor metals is substantial, with 2013 vehicle production in the United States, Canada, EU15, and Japan alone accounting for approximately 20% of global production of Mg and Ta and approximately 5% of Al, Cu, and Sn. The data and analysis provide researchers, recyclers, and decision-makers additional insight into the vehicle content of strategic and minor metals of current interest.

Critical review of lasers in benign prostatic hyperplasia (BPH).

PubMed

Gravas, Stavros; Bachmann, Alexander; Reich, Oliver; Roehrborn, Claus G; Gilling, Peter J; De La Rosette, Jean

2011-04-01

• Laser treatment of benign prostatic hyperplasia has challenged transurethral resection of the prostate (TURP) due to advances in laser technology, better understanding of tissue-laser interactions and growing clinical experience. • Various lasers have been introduced including neodymium: yttrium aluminium garnet (YAG), holmium (Ho):YAG, potassium titanyl phosphate:YAG, thulium(Tm) and diode laser. Based on the different wave-length dependent laser-prostatic tissue interactions, the main techniques are coagulation, vaporization, resection and enucleation. • The present review aims to help urologists to distinguish and to critically evaluate the role of different laser methods in the treatment by using an evidence-based approach. It also details further evidence for use in specific patient groups (in retention, on anticoagulation) and addresses the issues of cost and learning curve. • Coagulation-based techniques have been abandoned; holmium ablation/resection of the prostate has been superseded by the enucleation technique Ho-laser enucleation of the prostate (HoLEP). The short-term efficacy of the emerging laser treatments such as diode and Tm prostatectomy has been suggested by low quality studies. HoLEP and photoselective vaporization of the prostate (PVP) represent valid clinical alternatives to TURP. HoLEP is the most rigorously analysed laser technique with durable efficacy for any prostate size and low early and late morbidity. PVP has grown in acceptance and popularity but long-term results from high quality studies are pending. © 2010 THE AUTHORS; BJU INTERNATIONAL © 2010 BJU INTERNATIONAL.

Optimizing the Activation of Chlorin e6 Utilizing Upconversion Energy Transfer

NASA Astrophysics Data System (ADS)

Avalos, Julio C.; Pedraza, Francisco J.; Sardar, Dhiraj K.

2015-03-01

Current cancer therapy techniques, such as chemotherapy and radiation therapy, possess several drawbacks including lack of selectivity resulting in harmful side effects. Photodynamic therapy (PDT) is one of the fastest emerging techniques due to its many advantages, including the use of nonionizing radiation, targeted delivery, and controlled doses. In PDT, photosensitizers (PSs) are activated inside targeted cells to produce irreversible damage inducing cell death. Since most PSs operate in the visible range, it is difficult to activate them due to the high attenuation of soft tissue. Upconverting nanoparticles (UCNP) are able to absorb in the NIR region, where light is less attenuated, and emit in the visible range, resulting in deeper tissue penetration. UCNPs are able to assist with the activation of the PS by energy transfer when the PS is conjugated onto the UCNP. Chlorin e6 (Ce6) is a commonly used PSs due to its ability to release reactive oxygen species (ROS), which is one of the main processes utilized in PDT. The UCNP studied contain a combination of rare earth doped ions including Erbium, Thulium, and Holmium precisely doped into the host nanocrystal to improve upconversion emission and energy transfer. The work presented will focus on exploring the factors that affect the activation of Ce6. The results will include the enhancement of Ce6 activation and ROS release when conjugated onto a rare earth-doped UCNP. This research was funded by NSF-PREM Grant No. DMR -0934218 and RISE Grant No. GM 060655.

High-spin structure, K isomers, and state mixing in the neutron-rich isotopes 173Tm and 175Tm

NASA Astrophysics Data System (ADS)

Hughes, R. O.; Lane, G. J.; Dracoulis, G. D.; Byrne, A. P.; Nieminen, P. H.; Watanabe, H.; Carpenter, M. P.; Chowdhury, P.; Janssens, R. V. F.; Kondev, F. G.; Lauritsen, T.; Seweryniak, D.; Zhu, S.

2012-11-01

High-spin states in the odd-proton thulium isotopes 173Tm and 175Tm have been studied using deep-inelastic reactions and γ-ray spectroscopy. In 173Tm, the low-lying structure has been confirmed and numerous new states have been identified, including a three-quasiparticle Kπ= 19/2- isomer with a lifetime of τ=360(100) ns at 1906 keV and a five-quasiparticle Kπ=35/2- isomer with a lifetime of τ= 175(40) ns at 4048 keV. The Kπ=35/2- state is interpreted as a t-band configuration that shows anomalously fast decays. In 175Tm, the low-lying structure has been reevaluated, a candidate state for the 9/2-[514] orbital has been identified at 1175 keV, and the 7/2-[523] bandhead has been measured to have a lifetime of τ= 460(50) ns. Newly identified high-K structures in 175Tm include a Kπ=15/2- isomer with a lifetime of τ= 64(3) ns at 947 keV and a Kπ= 23/2+ isomer with a lifetime of τ= 30(20) μs at 1518 keV. The Kπ=15/2- isomer shows relatively enhanced decays to the 7/2-[523] band that can be explained by chance mixing with the 15/2- member of the 7/2- band. Multiquasiparticle calculations have been performed for 173Tm and 175Tm, the results of which compare well with the experimentally observed high-spin states.

Continued advances in high brightness fiber-coupled laser modules for efficient pumping of fiber and solid-state lasers

NASA Astrophysics Data System (ADS)

Hemenway, M.; Chen, Z.; Urbanek, W.; Dawson, D.; Bao, L.; Kanskar, M.; DeVito, M.; Martinsen, R.

2018-02-01

Both the fibber laser and diode-pumped solid-state laser market continue to drive advances in pump diode module brightness. We report on the continued progress by nLIGHT to develop and deliver the highest brightness diode-laser pumps using single-emitter technology. Continued advances in multimode laser diode technology [13] and fiber-coupling techniques have enabled higher emitter counts in the element packages, enabling us to demonstrate 305 W into 105 μm - 0.16 NA. This brightness improvement is achieved by leveraging our prior-reported package re-optimization, allowing an increase in the emitter count from two rows of nine emitters to two rows of twelve emitters. Leveraging the two rows off twelve emitter architecture,, product development has commenced on a 400 W into 200 μm - 00.16 NA package. Additionally, the advances in pump technology intended for CW Yb-doped fiber laser pumping has been leveraged to develop the highest brightness 793 nm pump modules for 2 μm Thulium fiber laser pumping, generating 150 W into 200 μm - 0.18 NA and 100 W into 105 μm - 0.15 NA. Lastly, renewed interest in direct diode materials processing led us to experiment with wavelength multiplexing our existing state of the art 200 W, 105 μm - 00.15 NA package into a combined output of 395 WW into 105 μm - 0.16 NA.

Observation of a Hydrodynamically Driven, Radiative Precursor Shock

NASA Astrophysics Data System (ADS)

Keiter, P. A.; Drake, R. P.; Perry, T. S.; Robey, H.; Remington, B. A.; Iglesias, C. A.; Turner, N.; Stone, J.; Knauer, J.

2001-10-01

Many astrophysical systems, such as supernova remnants and jets, produce radiative-precursor shock waves. In a radiative-precursor shock, radiation from the shock ionizes and heats the medium ahead of it. The simulation of such systems requires that one treat both the emission and the absorption of the radiation. An important goal of this effort is to produce an experiment that can be modeled by astrophysical codes without implementing laser absorption physics into an astrophysical code. We report here the first measurements of a radiative-precursor shock in such an experiment. The experimental design is based on a past experiment[1,2] that used the Nova laser facility to simulate young supernova remnants. The target consists of a 60 νm CH plastic plug followed by a 150 νm vacuum gap and 2 mm of SiO2 aerogel foam. For the experiment, the density of the components and the laser-irradiation conditions are chosen so that the driven shock will produce an observable radiative precursor. We observed the radiative-precursor by using absorption spectroscopy. By backlighting the silicate aerogel foam with a thulium backlighter, we were able to observe both the 1s-2p and 1s-3p lines. These observations will allow us to determine the temperature profile in the precursor. 1. R.P. Drake, et al, Phys. Rev. Lett. 81, 2068 (1998). 2. R.P. Drake, et al., Phys. Plasmas, 7, 2142 (2000) Work supported by the U.S. Department of Energy both directly and through the Lawrence Livermore National Laboratory

Double-Wall Carbon Nanotube Hybrid Mode-Locker in Tm-doped Fibre Laser: A Novel Mechanism for Robust Bound-State Solitons Generation

PubMed Central

Chernysheva, Maria; Bednyakova, Anastasia; Al Araimi, Mohammed; Howe, Richard C. T.; Hu, Guohua; Hasan, Tawfique; Gambetta, Alessio; Galzerano, Gianluca; Rümmeli, Mark; Rozhin, Aleksey

2017-01-01

The complex nonlinear dynamics of mode-locked fibre lasers, including a broad variety of dissipative structures and self-organization effects, have drawn significant research interest. Around the 2 μm band, conventional saturable absorbers (SAs) possess small modulation depth and slow relaxation time and, therefore, are incapable of ensuring complex inter-pulse dynamics and bound-state soliton generation. We present observation of multi-soliton complex generation in mode-locked thulium (Tm)-doped fibre laser, using double-wall carbon nanotubes (DWNT-SA) and nonlinear polarisation evolution (NPE). The rigid structure of DWNTs ensures high modulation depth (64%), fast relaxation (1.25 ps) and high thermal damage threshold. This enables formation of 560-fs soliton pulses; two-soliton bound-state with 560 fs pulse duration and 1.37 ps separation; and singlet+doublet soliton structures with 1.8 ps duration and 6 ps separation. Numerical simulations based on the vectorial nonlinear Schr¨odinger equation demonstrate a transition from single-pulse to two-soliton bound-states generation. The results imply that DWNTs are an excellent SA for the formation of steady single- and multi-soliton structures around 2 μm region, which could not be supported by single-wall carbon nanotubes (SWNTs). The combination of the potential bandwidth resource around 2 μm with the soliton molecule concept for encoding two bits of data per clock period opens exciting opportunities for data-carrying capacity enhancement. PMID:28287159

Rare earth elements and hypertension risk among housewives: A pilot study in Shanxi Province, China.

PubMed

Wang, Bin; Yan, Lailai; Huo, Wenhua; Lu, Qun; Cheng, Zixi; Zhang, Jingxu; Li, Zhiwen

2017-01-01

Studies have shown that residents living near rare earth mining areas have high concentrations of rare earth elements (REEs) in their hair. However, the adverse effects of REEs on human health have rarely been the focus of epidemiological studies. The goal of this study was to evaluate the relationship between REEs in hair and the risk of hypertension in housewives. We recruited 398 housewives in Shanxi Province, China, consisting of 163 women with hypertension (cases) and 235 healthy women without hypertension (controls). We analyzed 15 REEs (lanthanum (La), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), Yttrium (Y), cerium (Ce), praseodymium (Pr), and neodymium (Nd)) and calcium (Ca) accumulated in housewives hair over a period of two years. The results revealed that, with the exception of Eu, concentrations of the REEs in hair were higher in the cases than in the controls. The univariate odds ratios (ORs) of the 14 REEs were >1, and four of the REEs (Dy, Tm, Yb, and Y) also had adjusted ORs > 1. The increasing dose-response trends of the four REEs further indicated the potential for increased hypertension risk. Moreover, the REEs were negatively correlated with Ca content in hair. These results might suggest an antagonistic effect of REEs on Ca in the human body. It was concluded that high intake of REEs might increase the risk of hypertension among housewives. Copyright © 2016 Elsevier Ltd. All rights reserved.

The impact of minimally invasive surgeries for the treatment of symptomatic benign prostatic hyperplasia on male sexual function: a systematic review.

PubMed

Frieben, Ryan W; Lin, Hao-Cheng; Hinh, Peter P; Berardinelli, Francesco; Canfield, Steven E; Wang, Run

2010-07-01

A systematic review of randomized controlled trials and cohort studies was conducted to evaluate data for the effects of minimally invasive procedures for treatment of symptomatic benign prostatic hyperplasia (BPH) on male sexual function. The studies searched were trials that enrolled men with symptomatic BPH who were treated with laser surgeries, transurethral microwave therapy (TUMT), transurethral needle ablation of the prostate (TUNA), transurethral ethanol ablation of the prostate (TEAP) and high-intensity frequency ultrasound (HIFU), in comparison with traditional transurethral resection of the prostate (TURP) or sham operations. A total of 72 studies were identified, of which 33 met the inclusion criteria. Of the 33 studies, 21 were concerned with laser surgeries, six with TUMT, four with TUNA and two with TEAP containing information regarding male sexual function. No study is available regarding the effect of HIFU for BPH on male sexual function. Our analysis shows that minimally invasive surgeries for BPH have comparable effects to those of TURP on male erectile function. Collectively, less than 15.4% or 15.2% of patients will have either decrease or increase, respectively, of erectile function after laser procedures, TUMT and TUNA. As observed with TURP, a high incidence of ejaculatory dysfunction (EjD) is common after treatment of BPH with holmium, potassium-titanyl-phosphate and thulium laser therapies (> 33.6%). TUMT, TUNA and neodymium:yttrium aluminum garnet visual laser ablation or interstitial laser coagulation for BPH has less incidence of EjD, but these procedures are considered less effective for BPH treatment when compared with TURP.

The impact of minimally invasive surgeries for the treatment of symptomatic benign prostatic hyperplasia on male sexual function: a systematic review

PubMed Central

Frieben, Ryan W.; Lin, Hao-Cheng; Hinh, Peter P.; Berardinelli, Francesco; Canfield, Steven E.; Wang, Run

2010-01-01

A systematic review of randomized controlled trials and cohort studies was conducted to evaluate data for the effects of minimally invasive procedures for treatment of symptomatic benign prostatic hyperplasia (BPH) on male sexual function. The studies searched were trials that enrolled men with symptomatic BPH who were treated with laser surgeries, transurethral microwave therapy (TUMT), transurethral needle ablation of the prostate (TUNA), transurethral ethanol ablation of the prostate (TEAP) and high-intensity frequency ultrasound (HIFU), in comparison with traditional transurethral resection of the prostate (TURP) or sham operations. A total of 72 studies were identified, of which 33 met the inclusion criteria. Of the 33 studies, 21 were concerned with laser surgeries, six with TUMT, four with TUNA and two with TEAP containing information regarding male sexual function. No study is available regarding the effect of HIFU for BPH on male sexual function. Our analysis shows that minimally invasive surgeries for BPH have comparable effects to those of TURP on male erectile function. Collectively, less than 15.4% or 15.2% of patients will have either decrease or increase, respectively, of erectile function after laser procedures, TUMT and TUNA. As observed with TURP, a high incidence of ejaculatory dysfunction (EjD) is common after treatment of BPH with holmium, potassium-titanyl-phosphate and thulium laser therapies (> 33.6%). TUMT, TUNA and neodymium:yttrium aluminum garnet visual laser ablation or interstitial laser coagulation for BPH has less incidence of EjD, but these procedures are considered less effective for BPH treatment when compared with TURP. PMID:20473318

Adverse events resulting from lasers used in urology.

PubMed

Althunayan, Abdulaziz M; Elkoushy, Mohamed A; Elhilali, Mostafa M; Andonian, Sero

2014-02-01

To collate world reports of adverse events (AEs) resulting from lasers used in urology. The Manufacturer and User Facility Device Experience (MAUDE) database of the United States Food and Drug Administration (FDA) was searched using the term "Laser for gastro-urology use." In addition, the Rockwell Laser Industries (RLI) Laser Accident Database was searched for the following types of lasers: neodymium-doped yttrium aluminum garnet (Nd:YAG), holmium:yttrium aluminum garnet (Ho:YAG), potassium titanyl phosphate (KTP), diode and thulium:YAG (Tm:YAG). Both databases were last accessed on October 1, 2012. Overall, there were 433 AEs; 166 in MAUDE database (1992-2012) and 267 in RLI database (1964-2005). Most of the AEs (198/433 or 46%) resulted from generator failure or fiber tip breaking. Whereas there were 20 (4.6%) AEs harming medical operators, there were 159 (37%) AEs harming nonmedical operators using Nd:YAG, KTP, and diode lasers. Eye injuries ranging from mild corneal abrasions to total vision loss were reported in 164 AEs with the use of Nd:YAG, KTP, and diode lasers. Overall, there were 36 (8.3%) AEs resulting in patient harm, including 7 (1.6%) mortalities, 3 deaths from ureteral perforation using the Ho:YAG laser, and 4 deaths from air emboli using the Nd:YAG laser. Other reported patient injuries included bladder perforation resulting in urinary diversion in a patient, in addition to minor skin burns, internal burns, and bleeding in others. There were no AEs reported with the use of Tm:YAG laser. Most of the AEs reported relate to equipment failure. There were no eye injuries reported with the use of Ho:YAG lasers. Caution must be exercised when using lasers in urology, including wearing appropriate eye protection when using Nd:YAG, KTP, and diode lasers.

Stone Retropulsion with Ho: YAG and Tm: YAG Lasers: A Clinical Practice-Oriented Experimental Study.

PubMed

Kamal, Wissam; Kallidonis, Panagiotis; Koukiou, Georgia; Amanatides, Lefteris; Panagopoulos, Vasileios; Ntasiotis, Pantelis; Liatsikos, Evangelos

2016-11-01

To compare the retropulsion of stones with the use of holmium: yttrium aluminum garnet (Ho: YAG) laser and thulium: yttrium aluminum garnet (Tm: YAG) laser in settings that could be used in clinical practice. The experimental configuration included a glass tube set in a water bath filled with physiologic saline. Plaster of Paris stones were inserted in the tube. Tm: YAG and Ho: YAG laser systems were used along with a high-speed slow-motion camera. The lasers were activated with different settings. The displacement of the stone was measured according to a custom-made algorithm. Ho: YAG: the retropulsion of stones was the lowest with the energy setting of 0.5 J and the frequency of 20 Hz with long pulse duration. The highest retropulsion was observed in the case of 3 J, 5 Hz, and short pulse. Tm: YAG: the retropulsion of stones was the lowest with the energy setting of 1 J and the frequency of 10 Hz with either long or short pulse duration. Practically, there was no retropulsion at all. The highest retropulsion was observed in the case of 8 J, 5 Hz, and short pulse. Ho: YAG laser has a linear increase in stone retropulsion with increased pulse energy. On the other hand, the retropulsion rate was kept to the minimum with Tm: YAG as much as the energy level of 8 J. The activation of lasers with short pulse resulted in further displacement of the stone. Lower frequency with the same power setting seemed to result in further stone retropulsion. Higher power with the same frequency setting resulted in further displacement of the stone.

Fractional resurfacing in the Asian patient: Current state of the art.

PubMed

Wat, Heidi; Wu, Douglas C; Chan, Henry Hin Lee

2017-01-01

Fractionated photothermolysis (FP) has revolutionized modern laser technology. By creating selective columns of microthermal damage, fractionated devices allows for greater treatment depths to be achieved without the prolonged downtime and risk of complications seen in traditional fully ablative laser resurfacing. Fractional resurfacing is a proven method to treat a variety of cutaneous conditions. In the Caucasian patient, a wide range of devices and treatment settings can be utilized safely and effectively. However, ethnic skin requires special consideration due to its unique pigmentary characteristics and clinical presentations. In this review article, we detail the current indications and strategies to optimize results and mitigate complications when utilizing fractional resurfacing for the Asian patient. A review of the MEDLINE English literature was conducted on fractionated laser devices studied in the Asian population. Articles included describe non-ablative devices including fractionated erbium glass, thulium fiber, diode, and radiofrequency devices; and ablative devices including fractionated carbon dioxide (CO 2 ) laser, erbium yttrium aluminum garnet and yttrium scandium gallium garnet (YSGG) laser. These data were integrated with the expert opinion of the authors. Taking into account the unique characteristics and cosmetic concerns of the Asian population, fractional resurfacing can be considered a safe and effective option for the treatment of atrophic and hypertrophic scarring, and photorejuvenation in ethnic skin types. Select cases of melasma may be treated with fractionated non-ablative devices, but utilized with caution. The predominant complication associated with fractional resurfacing for these conditions is post-inflammatory hyperpigmentation (PIH) and rebound worsening of melasma. A greater number of treatments at lower density settings and wider treatment intervals typically produce the lowest risks of PIH without compromising treatment efficacy. Lasers Surg. Med. 49:45-59, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

All-fiber linearly polarized high power 2-μm single mode Tm-fiber laser for plastic processing and Ho-laser pumping applications

NASA Astrophysics Data System (ADS)

Scholle, K.; Schäfer, M.; Lamrini, S.; Wysmolek, M.; Steinke, M.; Neumann, J.; Fuhrberg, P.

2018-02-01

In this paper we present a high power, polarized 2 μm Thulium-doped fiber laser with high beam quality. Such laser systems are ideally suited for the processing of plastic materials which are highly transparent in the visible and 1 μm wavelength range and for the pumping of laser sources for the mid-IR wavelength region. For most applications polarized lasers are beneficial, as they can be easily protected from back reflections and combined with other laser sources or power scaled by polarization combining. The Tm-doped fiber laser is pumped in an all-fiber configuration by using a fiber coupled pump diode emitting around 790 nm. This pumping scheme allows the exploitation of the crossrelaxation process to populate the upper laser level. A compact and robust laser configuration was achieved by using an all-fiber configuration with single mode fibers and fiber Bragg gratings (FBG). Different FBG pairs with wavelength around 2 μm were tested. To achieve stable polarized output power the fibers with the FBG were 90° twisted at the splices. Stable linearly polarized output power up to 38 W with an extinction ratio of up to 50:1 was observed. With respect to the diode output power an optical-to-optical efficiency of 51 % was reached with a correspondent slope efficiency of 52 %. The emission linewidth at maximum power was measured to be < 0.3 nm which is well suitable for Ho-laser pumping. First tests of the precise processing of highly transparent plastic materials demonstrate the potentials of these laser systems.

Moderate high power 1 to 20μs and kHz Ho:YAG thin disk laser pulses for laser lithotripsy

NASA Astrophysics Data System (ADS)

Renz, Günther

2015-02-01

An acousto-optically or self-oscillation pulsed thin disk Ho:YAG laser system at 2.1 μm with an average power in the 10 W range will be presented for laser lithotripsy. In the case of cw operation the thin disk Ho:YAG is either pumped with InP diode stacks or with a thulium fiber laser which leads to a laser output power of 20 W at an optical-to-optical efficiency of 30%. For the gain switched mode of operation a modulated Tm-fiber laser is used to produce self-oscillation pulses. A favored pulse lengths for uric acid stone ablation is known to be at a few μs pulse duration which can be delivered by the thin disk laser technology. In the state of the art laser lithotripter, stone material is typically ablated with 250 to 750 μs pulses at 5 to 10 Hz and with pulse energies up to a few Joule. The ablation mechanism is performed in this case by vaporization into stone dust and fragmentation. With the thin disk laser technology, 1 to 20 μs-laser pulses with a repetition rate of a few kHz and with pulse energies in the mJ-range are available. The ablation mechanism is in this case due to a local heating of the stone material with a decomposition of the crystalline structure into calcium carbonate powder which can be handled by the human body. As a joint process to this thermal effect, imploding water vapor bubbles between the fiber end and the stone material produce sporadic shock waves which help clear out the stone dust and biological material.

Threshold voltage control in TmSiO/HfO2 high-k/metal gate MOSFETs

NASA Astrophysics Data System (ADS)

Dentoni Litta, E.; Hellström, P.-E.; Östling, M.

2015-06-01

High-k interfacial layers have been proposed as a way to extend the scalability of Hf-based high-k/metal gate CMOS technology, which is currently limited by strong degradations in threshold voltage control, channel mobility and device reliability when the chemical oxide (SiOx) interfacial layer is scaled below 0.4 nm. We have previously demonstrated that thulium silicate (TmSiO) is a promising candidate as a high-k interfacial layer, providing competitive advantages in terms of EOT scalability and channel mobility. In this work, the effect of the TmSiO interfacial layer on threshold voltage control is evaluated, showing that the TmSiO/HfO2 dielectric stack is compatible with threshold voltage control techniques commonly used with SiOx/HfO2 stacks. Specifically, we show that the flatband voltage can be set in the range -1 V to +0.5 V by the choice of gate metal and that the effective workfunction of the stack is properly controlled by the metal workfunction in a gate-last process flow. Compatibility with a gate-first approach is also demonstrated, showing that integration of La2O3 and Al2O3 capping layers can induce a flatband voltage shift of at least 150 mV. Finally, the effect of the annealing conditions on flatband voltage is investigated, finding that the duration of the final forming gas anneal can be used as a further process knob to tune the threshold voltage. The evaluation performed on MOS capacitors is confirmed by the fabrication of TmSiO/HfO2/TiN MOSFETs achieving near-symmetric threshold voltages at sub-nm EOT.

Towards Longitudinal Mapping of Extracellular pH in Gliomas

PubMed Central

Huang, Yuegao; Coman, Daniel; Herman, Peter; Rao, Jyotsna U.; Maritim, Samuel; Hyder, Fahmeed

2016-01-01

Biosensor Imaging of Redundant Deviation in Shifts (BIRDS), an ultrafast chemical shift imaging technique, requires infusion of paramagnetic probes like 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrakis(methylene phosphonate (DOTP8−) complexed with thulium (Tm3+) ion (i.e., TmDOTP5−), where the pH-sensitive resonances of hyperfine-shifted nonexchangeable protons contained within the paramagnetic magnetic resonance probe are detected. While imaging extracellular pH (pHe) with BIRDS meets an important cancer research need by mapping the intratumoral-peritumoral pHe gradient, the surgical intervention used to raise the probe’s plasma concentration limits longitudinal scans on the same subject. Here we describe using probenecid (i.e., an organic anion transporter inhibitor) to temporarily restrict renal clearance of TmDOTP5−, thereby facilitating molecular imaging by BIRDS without surgical intervention. Co-infusion of probenecid with TmDOTP5− increased the probe’s distribution into various organs, including the brain, compared with when infusing TmDOTP5− alone. In vivo BIRDS data using probenecid/TmDOTP5− co-infusion method in rats bearing RG2, 9L, and U87 brain tumors showed intratumoral-peritumoral pHe gradients that were unaffected by the probe dose. This co-infusion method can be used for pHe mapping with BIRDS in preclinical models for tumor characterization and therapeutic monitoring given the possibility of repeated scans with BIRDS (e.g., over days and even weeks) in the same subject. The longitudinal pHe readout by probenecid/TmDOTP5− co-infusion method for BIRDS adds translational value in tumor assessment and treatment. PMID:27472471

Atomic weights of the elements 2013 (IUPAC Technical Report)

USGS Publications Warehouse

Meija, Juris; Coplen, Tyler B.; Berglund, Michael; Brand, Willi A.; De Bièvre, Paul; Gröning, Manfred; Holden, Norman E.; Irrgeher, Johanna; Loss, Robert D.; Walczyk, Thomas; Prohaska, Thomas

2016-01-01

The biennial review of atomic-weight determinations and other cognate data has resulted in changes for the standard atomic weights of 19 elements. The standard atomic weights of four elements have been revised based on recent determinations of isotopic abundances in natural terrestrial materials:cadmium to 112.414(4) from 112.411(8),molybdenum to 95.95(1) from 95.96(2),selenium to 78.971(8) from 78.96(3), andthorium to 232.0377(4) from 232.038 06(2). The Commission on Isotopic Abundances and Atomic Weights (ciaaw.org) also revised the standard atomic weights of fifteen elements based on the 2012 Atomic Mass Evaluation:aluminium (aluminum) to 26.981 5385(7) from 26.981 5386(8),arsenic to 74.921 595(6) from 74.921 60(2),beryllium to 9.012 1831(5) from 9.012 182(3),caesium (cesium) to 132.905 451 96(6) from 132.905 4519(2),cobalt to 58.933 194(4) from 58.933 195(5),fluorine to 18.998 403 163(6) from 18.998 4032(5),gold to 196.966 569(5) from 196.966 569(4),holmium to 164.930 33(2) from 164.930 32(2),manganese to 54.938 044(3) from 54.938 045(5),niobium to 92.906 37(2) from 92.906 38(2),phosphorus to 30.973 761 998(5) from 30.973 762(2),praseodymium to 140.907 66(2) from 140.907 65(2),scandium to 44.955 908(5) from 44.955 912(6),thulium to 168.934 22(2) from 168.934 21(2), andyttrium to 88.905 84(2) from 88.905 85(2). The Commission also recommends the standard value for the natural terrestrial uranium isotope ratio, N(238U)/N(235U)=137.8(1).

China's rare-earth industry

USGS Publications Warehouse

Tse, Pui-Kwan

2011-01-01

Introduction China's dominant position as the producer of over 95 percent of the world output of rare-earth minerals and rapid increases in the consumption of rare earths owing to the emergence of new clean-energy and defense-related technologies, combined with China's decisions to restrict exports of rare earths, have resulted in heightened concerns about the future availability of rare earths. As a result, industrial countries such as Japan, the United States, and countries of the European Union face tighter supplies and higher prices for rare earths. This paper briefly reviews China's rare-earth production, consumption, and reserves and the important policies and regulations regarding the production and trade of rare earths, including recently announced export quotas. The 15 lanthanide elements-lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium (atomic numbers 57-71)-were originally known as the rare earths from their occurrence in oxides mixtures. Recently, some researchers have included two other elements-scandium and yttrium-in their discussion of rare earths. Yttrium (atomic number 39), which lies above lanthanum in transition group III of the periodic table and has a similar 3+ ion with a noble gas core, has both atomic and ionic radii similar in size to those of terbium and dysprosium and is generally found in nature with lanthanides. Scandium (atomic number 21) has a smaller ionic radius than yttrium and the lanthanides, and its chemical behavior is intermediate between that of aluminum and the lanthanides. It is found in nature with the lanthanides and yttrium. Rare earths are used widely in high-technology and clean-energy products because they impart special properties of magnetism, luminescence, and strength. Rare earths are also used in weapon systems to obtain the same properties.

Incorporation of fiber optic beam shaping into a laparoscopic probe for laser stimulation of the cavernous nerves

NASA Astrophysics Data System (ADS)

Tozburun, Serhat; Lagoda, Gwen A.; Mayeh, Mona; Burnett, Arthur L.; Farahi, Faramarz; Fried, Nathaniel M.

2010-02-01

The cavernous nerves (CN) course along the prostate surface and are responsible for erectile function. Improved identification and preservation of the CN's is critical to maintaining sexual potency after prostate cancer surgery. Noncontact optical nerve stimulation (ONS) of the CN's was recently demonstrated in a rat model, in vivo, as a potential alternative to electrical nerve stimulation (ENS) for identification of the CN's during prostate surgery. However, the therapeutic window for ONS is narrow, so optimal design of the fiber optic delivery system is critical for safe, reproducible stimulation. This study describes modeling, assembly, and testing of an ONS probe for delivering a small, collimated, flat-top laser beam for uniform CN stimulation. A direct comparison of the magnitude and response time of the intracavernosal pressure (ICP) for both Gaussian and flat-top spatial beam profiles was performed. Thulium fiber laser radiation (λ=1870 nm) was delivered through a 200-μm fiber, with distal fiber tip chemically etched to convert a Gaussian to flat-top beam profile. The laser beam was collimated to a 1-mm-diameter spot using an aspheric lens. Computer simulations of light propagation were used to optimize the probe design. The 10-Fr (3.4-mm-OD) laparoscopic probe provided a constant radiant exposure at the nerve surface. The probe was tested in four rats, in vivo. ONS of the CN's was performed with a 1-mm-diameter spot, 5- ms pulse duration, and pulse rate of 20 Hz for a duration of 15-30 s. The flat-top laser beam profile consistently produced a faster and higher ICP response at a lower radiant exposure than the Gaussian beam profile due, in part, to easier alignment of the more uniform beam with nerve. With further development, ONS may be used as a diagnostic tool for identification of the CN's during laparoscopic and robotic nerve-sparing prostate cancer surgery.

Water quality and quantity of selected springs and seeps along the Colorado River corridor, Utah and Arizona: Arches National Park, Canyonlands National Park, Glen Canyon National Recreation Area, and Grand Canyon National Park, 1997-98

USGS Publications Warehouse

Taylor, Howard E.; Spence, John R.; Antweiler, Ronald C.; Berghoff, Kevin; Plowman, Terry I.; Peart, Dale B.; Roth, David A.

2004-01-01

The U.S. Geological Survey, in cooperation with the National Park Service conducted an intensive assessment of selected springs along the Colorado River Corridor in Arches National Park, Canyonlands National Park, Glen Canyon National Recreation Area, and Grand Canyon National Park in 1997 and 1998, for the purpose of measuring and evaluating the water quality and quantity of the resource. This study was conducted to establish baseline data for the future evaluation of possible effects from recreational use and climate change. Selected springs and seeps were visited over a study period from 1997 to 1998, during which, discharge and on-site chemical measurements were made at selected springs and seeps, and samples were collected for subsequent chemical laboratory analysis. This interdisciplinary study also includes simultaneous studies of flora and fauna, measured and sampled coincidently at the same sites. Samples collected during this study were transported to U.S. Geological Survey laboratories in Boulder, Colorado, where analyses were performed using state-of-the-art laboratory technology. The location of the selected springs and seeps, elevation, geology, aspect, and onsite measurements including temperature, discharge, dissolved oxygen, pH, and specific conductance, were recorded. Laboratory analyses include determinations for alkalinity, aluminum, ammonium (nitrogen), antimony, arsenic, barium, beryllium, bismuth, boron, bromide, cadmium, calcium, cerium, cesium, chloride, chromium, cobalt, copper, dissolved inorganic carbon, dissolved organic carbon, dysprosium, erbium, europium, fluoride, gadolinium, holmium, iodine, iron, lanthanum, lead, lithium, lutetium, magnesium, manganese, mercury, molybdenum, neodymium, nickel, nitrate (nitrogen), nitrite (nitrogen), phosphate, phosphorus, potassium, praseodymium, rhenium, rubidium, samarium, selenium, silica, silver, sodium, strontium, sulfate, tellurium, terbium, thallium, thorium, thulium, tin, titanium, tungsten, uranium, vanadium, yttrium, ytterbium, zinc, and zirconium in these springs and seeps. Biological observations include physical setting, vegetation, invertebrate habitats, and invertebrate microhabitats.

High efficient bone ablation with diode pumped Erbium and Thulium lasers including different delivery fibers: a comparative in vitro study

NASA Astrophysics Data System (ADS)

Stock, Karl; Hausladen, Florian; Stegmayer, Thomas; Wurm, Holger

2018-02-01

Er:YAG lasers (3μm) allow efficient bone ablation caused by the strong absorption in water. Unfortunately, there are only a few and comparable expensive fiber materials for this wavelength available which are suitable for high laser power. The bone ablation efficiency of the Tm:YAG laser is minor (2μm) but inexpensive silica fibers can be used. The aim of this study was to investigate the bone ablation, using novel diode pumped high power Er:YAG (laser power 40W) and Tm:YAG laser system (60W) and adaptive fiber delivery systems. Expected advantage of these lasers is the longer lifetime of the fibers because of the high repetition rate and low pulse energy compared to the flash lamp pumped laser systems. The bare fiber output ends of a sapphire fiber (Er:YAG laser) and of a silica fiber (Tm:YAG laser) were attached under water and a water filled container including the fixed sample (bovine bone slices) was moved by a computer controlled translation stage. In a second set-up we provided a focusing unit and appropriate water spray unit. The generated cut kerfs were analyzed by light microcopy and laser scanning microscopy. The results show that with the diode pumped Er:YAG laser and sapphire fiber a particular high efficient bone ablation (> 0.16mm2/J) is possible both with bare fiber under water and focusing unit with water spray. The higher power of the Tm:YAG laser also results in high ablation rates but causes enlarged thermal damages. In conclusion, this study demonstrates that efficient bone ablation is possible with both diode pumped laser systems. In terms of efficiency the Er:YAG laser is outstanding. The Tm:YAG laser also allows fast bone ablation, provided that the thermal impact is limited by effective cooling and high movement velocity of the laser spot, for example by using an automatic scanner.

Selected trace elements in the Sacramento River, California: occurrence and distribution.

PubMed

Taylor, H E; Antweiler, R C; Roth, D A; Alpers, C N; Dileanis, P

2012-05-01

The impact of trace elements from the Iron Mountain Superfund site on the Sacramento River and selected tributaries is examined. The concentration and distribution of many trace elements-including aluminum, arsenic, boron, barium, beryllium, bismuth, cadmium, cerium, cobalt, chromium, cesium, copper, dysprosium, erbium, europium, iron, gadolinium, holmium, potassium, lanthanum, lithium, lutetium, manganese, molybdenum, neodymium, nickel, lead, praseodymium, rubidium, rhenium, antimony, selenium, samarium, strontium, terbium, thallium, thulium, uranium, vanadium, tungsten, yttrium, ytterbium, zinc, and zirconium-were measured using a combination of inductively coupled plasma-mass spectrometry and inductively coupled plasma-atomic emission spectrometry. Samples were collected using ultraclean techniques at selected sites in tributaries and the Sacramento River from below Shasta Dam to Freeport, California, at six separate time periods from mid-1996 to mid-1997. Trace-element concentrations in dissolved (ultrafiltered [0.005-μm pore size]) and colloidal material, isolated at each site from large volume samples, are reported. For example, dissolved Zn ranged from 900 μg/L at Spring Creek (Iron Mountain acid mine drainage into Keswick Reservoir) to 0.65 μg/L at the Freeport site on the Sacramento River. Zn associated with colloidal material ranged from 4.3 μg/L (colloid-equivalent concentration) in Spring Creek to 21.8 μg/L at the Colusa site on the Sacramento River. Virtually all of the trace elements exist in Spring Creek in the dissolved form. On entering Keswick Reservoir, the metals are at least partially converted by precipitation or adsorption to the particulate phase. Despite this observation, few of the elements are removed by settling; instead the majority is transported, associated with colloids, downriver, at least to the Bend Bridge site, which is 67 km from Keswick Dam. Most trace elements are strongly associated with the colloid phase going downriver under both low- and high-flow conditions.

Thulium fiber laser induced vapor bubbles using bare, tapered, ball, hollow steel, and muzzle brake fiber optic tips

NASA Astrophysics Data System (ADS)

Gonzalez, David A.; Hardy, Luke A.; Hutchens, Thomas C.; Irby, Pierce B.; Fried, Nathaniel M.

2018-02-01

This study characterizes laser-induced vapor bubbles for five distal fiber optic tip configurations, to provide insight into stone retropulsion experienced during laser ablation of kidney stones. A TFL with 1908-nm wavelength delivered 34 mJ energy per pulse at 500-μs pulse duration through five different fibers: 100-μm-core/170-μm-OD bare fiber tip, 150-μm- to 300-μm-core tapered fiber tip, 100-μm-core/300-μm-OD ball tip fiber, 100-μm-core/340- μm-OD hollow steel tip fiber, and 100-μm-core/560-μm-OD muzzle brake fiber tip. A high speed camera with 10- μm spatial and 9.5-μs temporal resolution imaged vapor bubble dynamics. A needle hydrophone measured pressure transients in forward (0°) and side (90°) directions while placed at a 6.8 +/- 0.4 mm distance from fiber tip. Maximum bubble dimensions (width/length) averaged 0.7/1.5, 1.0/1.6, 0.5/1.1, 0.8/1.9, and 0.7/1.5 mm, for bare, tapered, ball, hollow steel, and muzzle tips, respectively (n=5). The hollow steel tip exhibited the most elongated vapor bubble shape, translating into increased forward pressure in this study and consistent with higher stone retropulsion in previous reports. Relative pressures (a.u.) in (forward/side) directions averaged 1.7/1.6, 2.0/2.0, 1.4/1.2, 6.8/1.1, and 0.3/1.2, for each fiber tip (n=5). For hollow steel tip, forward pressure was 4× higher than for bare fiber. For the muzzle brake fiber tip, forward pressure was 5× lower than for bare fiber. Bubble dimensions and pressure measurements demonstrated that the muzzle tip reduced forward pressure by partially venting vapors through side holes, consistent with lower stone retropulsion observed in previous reports.

Selected trace elements in the Sacramento River, California: Occurrence and distribution

USGS Publications Warehouse

Taylor, Howard E.; Antweiler, Ronald C.; Roth, David A.; Dileanis, Peter D.; Alpers, Charles N.

2012-01-01

The impact of trace elements from the Iron Mountain Superfund site on the Sacramento River and selected tributaries is examined. The concentration and distribution of many trace elements—including aluminum, arsenic, boron, barium, beryllium, bismuth, cadmium, cerium, cobalt, chromium, cesium, copper, dysprosium, erbium, europium, iron, gadolinium, holmium, potassium, lanthanum, lithium, lutetium, manganese, molybdenum, neodymium, nickel, lead, praseodymium, rubidium, rhenium, antimony, selenium, samarium, strontium, terbium, thallium, thulium, uranium, vanadium, tungsten, yttrium, ytterbium, zinc, and zirconium—were measured using a combination of inductively coupled plasma-mass spectrometry and inductively coupled plasma-atomic emission spectrometry. Samples were collected using ultraclean techniques at selected sites in tributaries and the Sacramento River from below Shasta Dam to Freeport, California, at six separate time periods from mid-1996 to mid-1997. Trace-element concentrations in dissolved (ultrafiltered [0.005-μm pore size]) and colloidal material, isolated at each site from large volume samples, are reported. For example, dissolved Zn ranged from 900 μg/L at Spring Creek (Iron Mountain acid mine drainage into Keswick Reservoir) to 0.65 μg/L at the Freeport site on the Sacramento River. Zn associated with colloidal material ranged from 4.3 μg/L (colloid-equivalent concentration) in Spring Creek to 21.8 μg/L at the Colusa site on the Sacramento River. Virtually all of the trace elements exist in Spring Creek in the dissolved form. On entering Keswick Reservoir, the metals are at least partially converted by precipitation or adsorption to the particulate phase. Despite this observation, few of the elements are removed by settling; instead the majority is transported, associated with colloids, downriver, at least to the Bend Bridge site, which is 67 km from Keswick Dam. Most trace elements are strongly associated with the colloid phase going downriver under both low- and high-flow conditions.

Lanthanide ion (III) complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate (DOTA-4AmP8−) for dual biosensing of pH with CEST (chemical exchange saturation transfer) and BIRDS (biosensor imaging of redundant deviation in shifts)

PubMed Central

Huang, Yuegao; Coman, Daniel; Ali, Meser M.; Hyder, Fahmeed

2014-01-01

Relaxivity based magnetic resonance of phosphonated ligands chelated with gadolinium (Gd3+) shows promise for pH imaging. However instead of monitoring the paramagnetic effect of lanthanide complexes on the relaxivity of water protons, biosensor (or molecular) imaging with magnetic resonance is also possible by detecting either the non-exchangeable or the exchangeable protons on the lanthanide complexes themselves. The non-exchangeable protons (e.g., –CHx, where 3≥x≥1) are detected using a three-dimensional chemical shift imaging method called Biosensor Imaging of Redundant Deviation in Shifts (BIRDS), whereas the exchangeable protons (e.g., –OH or –NHy, where 2≥y≥1) are measured with Chemical Exchange Saturation Transfer (CEST) contrast. Here we tested the feasibility of BIRDS and CEST for pH imaging of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate (DOTA-4AmP8−) chelated with thulium (Tm3+) and ytterbium (Yb3+). BIRDS and CEST experiments show that both complexes are responsive to pH and temperature changes. Higher pH and temperature sensitivities are obtained with BIRDS for either complex when using the chemical shift difference between two proton resonances vs. using the chemical shift of a single proton resonance, thereby eliminating the need to use water resonance as reference. While CEST contrast for both agents is linearly dependent on pH within a relatively large range (i.e., 6.3-7.9), much stronger CEST contrast is obtained with YbDOTA-4AmP5− than with TmDOTA-4AmP5−. In addition, we demonstrate the prospect of using BIRDS to calibrate CEST as new platform for quantitative pH imaging. PMID:24801742

Preparation of Ho3+/Tm3+ Co-doped Lanthanum Tungsten Germanium Tellurite Glass Fiber and Its Laser Performance for 2.0 μm.

PubMed

Zhou, Dechun; Bai, Xuemei; Zhou, Hang

2017-03-17

Ho 3+ /Tm 3+ co-doped 50TeO 2 -25GeO 2 -3WO 3 -5La 2 O 3 -3Nb 2 O 5 -5Li 2 O-9BaF 2 glass fiber is prepared with the rod-tube drawing method of 15 μm core diameter and 125 μm inner cladding diameter applied in the 2.0 μm-infrared laser. The 2.0 μm luminescence properties of the core glass are researched and the fluorescence intensity variation for different Tm 3+ doping concentration is systematically analyzed. The results show that the 2.0 μm luminescence of Ho 3+ is greatly influenced by the doping concentration ratio of Ho 3+ to Tm 3+ and that the maximum fluorescence intensity of the core glass can be obtained and its emission cross section can reach 0.933 × 10 -21  cm 2 when the sensitized proportion of holmium to thulium is 0.3 to 0.7 (mol%). Simultaneously, the maximum phonon energy of the core glass sample is 753 cm -1 , which is significantly lower than that of silicate, gallate and germanate glass and the smaller matrix phonon energy can be conductive to the increase 2.0 μm-band emission intensity. The continuous laser with the maximum laser output power of 0.993 W and 2051 nm -wavelength of 31.9%-slope efficiency is output within the 0.5 m glass fiber and the experiment adopts 1560 nm erbium-doped fiber laser(EDFL) as the pump source and the self-built all-fiber laser. Therefore, the glass fiber has excellent laser characteristics and it is suitable for the 2.0 μm-band laser.

Preparation of Ho3+/Tm3+ Co-doped Lanthanum Tungsten Germanium Tellurite Glass Fiber and Its Laser Performance for 2.0 μm

NASA Astrophysics Data System (ADS)

Zhou, Dechun; Bai, Xuemei; Zhou, Hang

2017-03-01

Ho3+/Tm3+ co-doped 50TeO2-25GeO2-3WO3-5La2O3-3Nb2O5-5Li2O-9BaF2 glass fiber is prepared with the rod-tube drawing method of 15 μm core diameter and 125 μm inner cladding diameter applied in the 2.0 μm-infrared laser. The 2.0 μm luminescence properties of the core glass are researched and the fluorescence intensity variation for different Tm3+ doping concentration is systematically analyzed. The results show that the 2.0 μm luminescence of Ho3+ is greatly influenced by the doping concentration ratio of Ho3+ to Tm3+ and that the maximum fluorescence intensity of the core glass can be obtained and its emission cross section can reach 0.933 × 10-21 cm2 when the sensitized proportion of holmium to thulium is 0.3 to 0.7 (mol%). Simultaneously, the maximum phonon energy of the core glass sample is 753 cm-1, which is significantly lower than that of silicate, gallate and germanate glass and the smaller matrix phonon energy can be conductive to the increase 2.0 μm-band emission intensity. The continuous laser with the maximum laser output power of 0.993 W and 2051 nm -wavelength of 31.9%-slope efficiency is output within the 0.5 m glass fiber and the experiment adopts 1560 nm erbium-doped fiber laser(EDFL) as the pump source and the self-built all-fiber laser. Therefore, the glass fiber has excellent laser characteristics and it is suitable for the 2.0 μm-band laser.

Amplified stimulated emission in upconversion nanoparticles for super-resolution nanoscopy

NASA Astrophysics Data System (ADS)

Liu, Yujia; Lu, Yiqing; Yang, Xusan; Zheng, Xianlin; Wen, Shihui; Wang, Fan; Vidal, Xavier; Zhao, Jiangbo; Liu, Deming; Zhou, Zhiguang; Ma, Chenshuo; Zhou, Jiajia; Piper, James A.; Xi, Peng; Jin, Dayong

2017-02-01

Lanthanide-doped glasses and crystals are attractive for laser applications because the metastable energy levels of the trivalent lanthanide ions facilitate the establishment of population inversion and amplified stimulated emission at relatively low pump power. At the nanometre scale, lanthanide-doped upconversion nanoparticles (UCNPs) can now be made with precisely controlled phase, dimension and doping level. When excited in the near-infrared, these UCNPs emit stable, bright visible luminescence at a variety of selectable wavelengths, with single-nanoparticle sensitivity, which makes them suitable for advanced luminescence microscopy applications. Here we show that UCNPs doped with high concentrations of thulium ions (Tm3+), excited at a wavelength of 980 nanometres, can readily establish a population inversion on their intermediate metastable 3H4 level: the reduced inter-emitter distance at high Tm3+ doping concentration leads to intense cross-relaxation, inducing a photon-avalanche-like effect that rapidly populates the metastable 3H4 level, resulting in population inversion relative to the 3H6 ground level within a single nanoparticle. As a result, illumination by a laser at 808 nanometres, matching the upconversion band of the 3H4 → 3H6 transition, can trigger amplified stimulated emission to discharge the 3H4 intermediate level, so that the upconversion pathway to generate blue luminescence can be optically inhibited. We harness these properties to realize low-power super-resolution stimulated emission depletion (STED) microscopy and achieve nanometre-scale optical resolution (nanoscopy), imaging single UCNPs; the resolution is 28 nanometres, that is, 1/36th of the wavelength. These engineered nanocrystals offer saturation intensity two orders of magnitude lower than those of fluorescent probes currently employed in stimulated emission depletion microscopy, suggesting a new way of alleviating the square-root law that typically limits the resolution that can be practically achieved by such techniques.

Lanthanide ion (III) complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate for dual biosensing of pH with chemical exchange saturation transfer (CEST) and biosensor imaging of redundant deviation in shifts (BIRDS).

PubMed

Huang, Yuegao; Coman, Daniel; Ali, Meser M; Hyder, Fahmeed

2015-01-01

Relaxivity-based magnetic resonance of phosphonated ligands chelated with gadolinium (Gd(3+)) shows promise for pH imaging. However instead of monitoring the paramagnetic effect of lanthanide complexes on the relaxivity of water protons, biosensor (or molecular) imaging with magnetic resonance is also possible by detecting either the nonexchangeable or the exchangeable protons on the lanthanide complexes themselves. The nonexchangeable protons (e.g. -CHx, where 3 ≥ x ≥ 1) are detected using a three-dimensional chemical shift imaging method called biosensor imaging of redundant deviation in shifts (BIRDS), whereas the exchangeable protons (e.g. -OH or -NHy , where 2 ≥ y ≥ 1) are measured with chemical exchange saturation transfer (CEST) contrast. Here we tested the feasibility of BIRDS and CEST for pH imaging of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate (DOTA-4AmP(8-)) chelated with thulium (Tm(3+) ) and ytterbium (Yb(3+)). BIRDS and CEST experiments show that both complexes are responsive to pH and temperature changes. Higher pH and temperature sensitivities are obtained with BIRDS for either complex when using the chemical shift difference between two proton resonances vs using the chemical shift of a single proton resonance, thereby eliminating the need to use water resonance as reference. While CEST contrast for both agents is linearly dependent on pH within a relatively large range (i.e. 6.3-7.9), much stronger CEST contrast is obtained with YbDOTA-4AmP(5-) than with TmDOTA-4AmP(5-). In addition, we demonstrate the prospect of using BIRDS to calibrate CEST as new platform for quantitative pH imaging. Copyright © 2014 John Wiley & Sons, Ltd.

Preparation of Ho3+/Tm3+ Co-doped Lanthanum Tungsten Germanium Tellurite Glass Fiber and Its Laser Performance for 2.0 μm

PubMed Central

Zhou, Dechun; Bai, Xuemei; Zhou, Hang

2017-01-01

Ho3+/Tm3+ co-doped 50TeO2-25GeO2-3WO3-5La2O3-3Nb2O5-5Li2O-9BaF2 glass fiber is prepared with the rod-tube drawing method of 15 μm core diameter and 125 μm inner cladding diameter applied in the 2.0 μm-infrared laser. The 2.0 μm luminescence properties of the core glass are researched and the fluorescence intensity variation for different Tm3+ doping concentration is systematically analyzed. The results show that the 2.0 μm luminescence of Ho3+ is greatly influenced by the doping concentration ratio of Ho3+ to Tm3+ and that the maximum fluorescence intensity of the core glass can be obtained and its emission cross section can reach 0.933 × 10−21 cm2 when the sensitized proportion of holmium to thulium is 0.3 to 0.7 (mol%). Simultaneously, the maximum phonon energy of the core glass sample is 753 cm−1, which is significantly lower than that of silicate, gallate and germanate glass and the smaller matrix phonon energy can be conductive to the increase 2.0 μm-band emission intensity. The continuous laser with the maximum laser output power of 0.993 W and 2051 nm -wavelength of 31.9%-slope efficiency is output within the 0.5 m glass fiber and the experiment adopts 1560 nm erbium-doped fiber laser(EDFL) as the pump source and the self-built all-fiber laser. Therefore, the glass fiber has excellent laser characteristics and it is suitable for the 2.0 μm-band laser. PMID:28303946

Materials Development and Spin Transport Study of Magnetic Insulator Based Heterostructures

NASA Astrophysics Data System (ADS)

Tang, Chi

The subfield of magnetic insulator (MI) based spintronics is playing a substantial role in modern solid state physics research. Spin current in the MI is propagated in spin wave with a much longer decay length than spin-polarized carriers in conducting ferromagnet. In the MI-based hetereostructures, the adjacent non-magnetic materials can be magnetized in proximity of MI. Therefore, it is a promising system to study exotic transport phenomena such as quantum Anomalous Hall effect in topological insulator and graphene. Rare-earth Iron garnet (ReIG), a class of magnetic insulators with large electronic bandgap and high Curie temperature, stands out among various magnetic insulator materials and have attracted a great deal of attention in recent magnetic insulator based spintronics research. The first chapter of this dissertation gives a brief introduction to the spintronics research by introducing some essential concepts in the spintronics field and the most recent spin transport phenomena. The second chapter of this dissertation summarizes my work in the materials development of ReIG ferrimagnetic insulators, including exquisite control of high quality ultra-flat yttrium iron garnet (YIG) thin films with extremely low magnetic damping and engineering of strain induced robust perpendicular magnetic anisotropy in thulium iron garnet (TIG) and Bi-doped YIG films. The last chapter of this dissertation shows a systematic study in various ReIG based heterostructures, mainly divided into groups: ReIG (YIG & TIG)/heavy metal bilayers (Pd & Pt) and ReIG (YIG & TIG)/Dirac systems (graphene & topological insulator). The magneto-transport study disentangles the contribution from a spin current origin and proximity induced magnetism. Furthermore, the demonstration in the proximity coupling induced high-temperature ferromagnetic phase in low-dimensional Dirac systems, i.e. graphene and topological insulator surface states, provides new possibilities in the future spintronics applications. The modulation on the spin dynamics of magnetic insulator layer by topological insulator surface states is investigated at last, further confirming the superb properties of such magnetic insulator based spintronics systems.

TUNGSTEN BRONZE RELATED NON-NOBLE ELECTROCATALYSTS.

DTIC Science & Technology

FUEL CELLS, *CATALYSTS), (*OXYGEN, *ELECTRODES), (* SILICIDES , ELECTRODES), (*CARBIDES, ELECTRODES), (*TUNGSTEN COMPOUNDS, *ELECTROCHEMISTRY...CATALYSTS, TITANIUM COMPOUNDS, ZIRCONIUM COMPOUNDS, VANADIUM COMPOUNDS, NIOBIUM COMPOUNDS, TUNGSTEN COMPOUNDS, TANTALUM COMPOUNDS, MOLYBDENUM COMPOUNDS, SULFURIC ACID, CRYSTAL GROWTH, SODIUM COMPOUNDS

Pharmacists' Perceptions of the Economic Value of Compounded Pharmaceuticals: A Comparison of Compounded and Commercial Pharmaceuticals in Select Disease States.

PubMed

Lobb, William B; Wilkin, Noel E; Holmes, Erin R

2015-01-01

Studies have been conducted to assess patient satisfaction with compounded pharmaceuticals and to directly compare compounded pharmaceuticals with their comparable commercial pharmaceuticals. Yet, the economic value of or potential for economic value derived from compounded pharmaceuticals relative to commercial pharmaceuticals is still not known. Therefore, the purpose of this study was to assess and compare compounding and non-compounding pharmacists' perceptions of the economic value of compounded preparations relative to commercial products. In-depth interviews with 10 compounding pharmacists and physicians who prescribe compounded prescription pharmaceutical preparations were conducted to help develop a self-administered questionnaire distributed to 50 compounding and 50 non-compounding pharmacists. Compounding and non-compounding pharmacists' perceptions differed most often in the context of compounded pharmaceuticals for pediatric patients. However, both groups responded with moderate agreement that compounded prescription treatments are more profitable for the pharmacy than commercial prescription treatments in most therapeutic areas. This research sought to understand the perception of pharmacists of areas for potential direct and indirect economic cost savings as a result of compounding. For all items whereby compounding and non-compounding pharmacists' ratings were significantly different, compounding pharmacists more strongly believed that compounding pharmaceuticals offered benefit and vice versa. The differences in ratings that were most common were those that directly compared the economic value of compounding and commercial pharmaceuticals, with compounding pharmacists more strongly agreeing with the potential cost savings associated with compounded pharmaceuticals. Based on these findings, prescription compounds are believed to have a benefit to the health system by those who provide them. Future research should proactively explore the economic benefit of compounded preparations compared to conventionally manufactured products to determine the economic value of compounded pharmaceuticals for patients, pharmacies, physicians, and the healthcare system.

Energy efficient synthesis of boranes

DOEpatents

Thorn, David L [Los Alamos, NM; Tumas, William [Los Alamos, NM; Schwarz, Daniel E [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM

2012-01-24

The reaction of halo-boron compounds (B--X compounds, compounds having one or more boron-halogen bonds) with silanes provides boranes (B--H compounds, compounds having one or more B--H bonds) and halosilanes. Inorganic hydrides, such as surface-bound silane hydrides (Si--H) react with B--X compounds to form B--H compounds and surface-bound halosilanes. The surface bound halosilanes are converted back to surface-bound silanes electrochemically. Halo-boron compounds react with stannanes (tin compounds having a Sn--H bond) to form boranes and halostannanes (tin compounds having a Sn--X bond). The halostannanes are converted back to stannanes electrochemically or by the thermolysis of Sn-formate compounds. When the halo-boron compound is BCl.sub.3, the B--H compound is B.sub.2H.sub.6, and where the reducing potential is provided electrochemically or by the thermolysis of formate.

Energy efficient synthesis of boranes

DOEpatents

Thorn, David L.; Tumas, William; Schwarz, Daniel E.; Burrell, Anthony K.

2010-11-23

The reaction of halo-boron compounds (B--X compounds, compounds having one or more boron-halogen bonds) with silanes provides boranes (B--H compounds, compounds having one or more B--H bonds) and halosilanes. Inorganic hydrides, such as surface-bound silane hydrides (Si--H) react with B--X compounds to form B--H compounds and surface-bound halosilanes. The surface bound halosilanes are converted back to surface-bound silanes electrochemically. Halo-boron compounds react with stannanes (tin compounds having a Sn--H bond) to form boranes and halostannanes (tin compounds having a Sn--X bond). The halostannanes are converted back to stannanes electrochemically or by the thermolysis of Sn-formate compounds. When the halo-boron compound is BCl.sub.3, the B--H compound is B.sub.2H.sub.6, and where the reducing potential is provided electrochemically or by the thermolysis of formate.

Arylglycerol-γ-Formyl Ester as an Aromatic Ring Cleavage Product of Nonphenolic β-O-4 Lignin Substructure Model Compounds Degraded by Coriolus versicolor†

PubMed Central

Kawai, Shingo; Umezawa, Toshiaki; Higuchi, Takayoshi

1985-01-01

4-Ethoxy-3-methoxyphenylglycerol-γ-formyl ester (compound IV) was identified as a degradation product of both 4-ethoxy-3-methoxyphenylglycerol-β-syringaldehyde ether (compound I) and 4-ethoxy-3-methoxyphenylglycerol-β-2,6-dimethoxyphenyl ether (compound II) by a ligninolytic culture of Coriolus versicolor. An isotopic experiment with a 13C-labeled compound (compound II′) indicated that the formyl group of compound IV was derived from the β-phenoxyl group of β-O-4 dimer as an aromatic ring cleavage fragment. However, compound IV was not formed from 4-ethoxy-3-methoxyphenylglycerol-β-guaiacyl ether (compound III). γ-Formyl arylglycerol (compound IV) could be a precursor of 4-ethoxy-3-methoxyphenylglycerol (compound VI), because 3-(4-ethoxy-3-methoxyphenyl)-1-formyloxy propane (compound VII) was cleaved to give 3-(4-ethoxy-3-methoxyphenyl)-1-propanol (compound VIII) by C. versicolor. 4-Ethoxy-3-methoxyphenylglycerol-β,γ-cyclic carbonate (compound V), previously found as a degradation product of compound III by Phanerochaete chrysosporium (T. Umezawa, and T. Higuchi, FEBS Lett., 25:123-126, 1985), was also identified from the cultures with compound I, II, and III and degraded to give the arylglycerol (compound VI). An isotopic experiment with 13C-labeled compounds II′ and III′ indicated that the carbonate carbon of compound V was derived from the β-phenoxyl groups of β-O-4 substructure. PMID:16346950

Developing a novel dual PI3K–mTOR inhibitor from the prodrug of a metabolite

PubMed Central

Zhou, Yan; Zhang, Genyan; Wang, Feng; Wang, Jin; Ding, Yanwei; Li, Xinyu; Shi, Chongtie; Li, Jiakui; Shih, Chengkon; You, Song

2017-01-01

This study presents a process of developing a novel PI3K–mTOR inhibitor through the prodrug of a metabolite. The lead compound (compound 1) was identified with similar efficacy as that of NVP-BEZ235 in a tumor xenograft model, but the exposure of compound 1 was much lower than that of NVP-BEZ235. After reanalysis of the blood sample, a major metabolite (compound 2) was identified. Compound 2 exerted similar in vitro activity as compound 1, which indicated that compound 2 was an active metabolite and that the in vivo efficacy in the animal model came from compound 2 instead of compound 1. However, compound 1 was metabolized into compound 2 predominantly in the liver microsomes of mouse, but not in the liver microsomes of rat, dog, or human. In order to translate the efficacy in the animal model into clinical development or predict the pharmacokinetic/pharmacodynamic parameters in the clinical study using a preclinical model, we developed the metabolite (compound 2) instead of compound 1. Due to the low bioavailability of compound 2, its prodrug (compound 3) was designed and synthesized to improve the solubility. The prodrug was quickly converted to compound 2 through both intravenous and oral administrations. Because the prodrug (compound 3) did not improve the oral exposure of compound 2, developing compound 3 as an intravenous drug was considered by our team, and the latest results will be reported in the future. PMID:29118584

THE DIFFERENTIAL THERMAL ANALYSIS OF CYANO-TRANSITION METAL COMPLEXES

DTIC Science & Technology

COMPOUNDS, CHROMATES, COBALT COMPOUNDS, CYANIDES, CYANOGEN, DYES, FERRATES , GASES, HEAT, HYDROXIDES, LITHIUM COMPOUNDS, MOLYBDATES, NICKELATES, NITRATES...OXIDATION REDUCTION REACTIONS, POTASSIUM COMPOUNDS, SILVER COMPOUNDS, SODIUM COMPOUNDS, VANADATES

Preparation of cuxinygazsen precursor films and powders by electroless deposition

DOEpatents

Bhattacharya, Raghu N.; Batchelor, Wendi Kay; Wiesner, Holm; Ramanathan, Kannan; Noufi, Rommel

1999-01-01

A method for electroless deposition of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) precursor films and powders onto a metallic substrate comprising: preparing an aqueous bath solution of compounds selected from the group consisting of: I) a copper compound, a selenium compound, an indium compound and gallium compound; II) a copper compound, a selenium compound and an indium compound; III) a selenium compound, and indium compound and a gallium compound; IV) a selenium compound and a indium compound; and V) a copper compound and selenium compound; each compound being present in sufficient quantity to react with each other to produce Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3); adjusting the pH of the aqueous bath solution to an acidic value by the addition of a dilute acid; and initiating an electroless reaction with an oxidizing counterelectrode for a sufficient time to cause a deposit of Cu.sub.x In.sub.y Ga.sub.z Se.sub.n (x=0-2, y=0-2, z=0-2, n=0-3) from the aqueous bath solution onto a metallic substrate.

Carbon Dioxide Utilization by the Five-Membered Ring Products of Cyclometalation Reactions

PubMed Central

Omae, Iwao

2016-01-01

In carbon dioxide utilization by cyclometalated five-membered ring products, the following compounds are used in four types of applications: 1. 2-Phenylpyrazole iridium compounds, pincer phosphine iridium compounds and 2-phenylimidazoline iridium compounds are used as catalysts for both formic acid production from CO2 and H2, and hydrogen production from the formic acid. This formic acid can be a useful agent for H2 production and storage for fuel cell electric vehicles. 2. Other chemicals, e.g., dimethyl carbonate, methane, methanol and CO, are produced with dimethylaminomethylphenyltin compounds, pincer phosphine iridium compounds, pincer phosphine nickel compound and ruthenium carbene compound or 2-phenylpyridine iridium compounds, and phenylbenzothiazole iridium compounds as the catalysts for the reactions with CO2. 3. The five-membered ring intermediates of cyclometalation reactions with the conventional substrates react with carbon dioxide to afford their many types of carboxylic acid derivatives. 4. Carbon dioxide is easily immobilized at room temperature with immobilizing agents such as pincer phosphine nickel compounds, pincer phosphine palladium compounds, pincer N,N-dimethylaminomethyltin compounds and tris(2-pyridylthio)methane zinc compounds. PMID:28503084

Carbon Dioxide Utilization by the Five-Membered Ring Products of Cyclometalation Reactions.

PubMed

Omae, Iwao

2016-04-01

In carbon dioxide utilization by cyclometalated five-membered ring products, the following compounds are used in four types of applications: 1. 2-Phenylpyrazole iridium compounds, pincer phosphine iridium compounds and 2-phenylimidazoline iridium compounds are used as catalysts for both formic acid production from CO 2 and H 2 , and hydrogen production from the formic acid. This formic acid can be a useful agent for H 2 production and storage for fuel cell electric vehicles. 2. Other chemicals, e.g. , dimethyl carbonate, methane, methanol and CO, are produced with dimethylaminomethylphenyltin compounds, pincer phosphine iridium compounds, pincer phosphine nickel compound and ruthenium carbene compound or 2-phenylpyridine iridium compounds, and phenylbenzothiazole iridium compounds as the catalysts for the reactions with CO 2 . 3. The five-membered ring intermediates of cyclometalation reactions with the conventional substrates react with carbon dioxide to afford their many types of carboxylic acid derivatives. 4. Carbon dioxide is easily immobilized at room temperature with immobilizing agents such as pincer phosphine nickel compounds, pincer phosphine palladium compounds, pincer N , N -dimethylaminomethyltin compounds and tris(2-pyridylthio)methane zinc compounds.

Ionic Fluorine Chemistry.

DTIC Science & Technology

SOLID ROCKET OXIDIZERS, *LIQUID ROCKET OXIDIZERS, CHLORATES, FLUORIDES, ACETONES, CHLORINE COMPOUNDS, NITROSO COMPOUNDS, *HALOGEN COMPOUNDS, ADDITION REACTIONS, CESIUM COMPOUNDS, CHLORIDES, COMPLEX COMPOUNDS

Independent Community Pharmacists' Perspectives on Compounding in Contemporary Pharmacy Education

PubMed Central

McPherson, Timothy B.; Fontane, Patrick E.; Berry, Tricia; Chereson, Rasma; Bilger, Rhonda

2009-01-01

Objectives To identify compounding practices of independent community pharmacy practitioners in order to make recommendations for the development of curricular objectives for doctor of pharmacy (PharmD) programs. Methods Independent community practitioners were asked about compounding regarding their motivations, common activities, educational exposures, and recommendations for PharmD education. Results Most respondents (69%) accepted compounding as a component of pharmaceutical care and compounded dermatological preparations for local effects, oral solutions, and suspensions at least once a week. Ninety-five percent were exposed to compounding in required pharmacy school courses and most (98%) who identified compounding as a professional service offered in their pharmacy sought additional postgraduate compounding education. Regardless of the extent of compounding emphasis in the practices surveyed, 84% stated that PharmD curricula should include compounding. Conclusions Pharmacy schools should define compounding curricular objectives and develop compounding abilities in a required laboratory course to prepare graduates for pharmaceutical care practice. PMID:19564997

Reductive precipitation of metals photosensitized by tin and antimony porphyrins

DOEpatents

Shelnutt, John A.; Gong, Weiliang; Abdelouas, Abdesselam; Lutze, Werner

2003-09-30

A method for reducing metals using a tin or antimony porphyrin by forming an aqueous solution of a tin or antimony porphyrin, an electron donor, such as ethylenediaminetetraaceticacid, triethylamine, triethanolamine, and sodium nitrite, and at least one metal compound selected from a uranium-containing compound, a mercury-containing compound, a copper-containing compound, a lead-containing compound, a gold-containing compound, a silver-containing compound, and a platinum-containing compound through irradiating the aqueous solution with light.

Volatile flavor compounds in yogurt: a review.

PubMed

Cheng, Hefa

2010-11-01

Considerable knowledge has been accumulated on the volatile compounds contributing to the aroma and flavor of yogurt. This review outlines the production of the major flavor compounds in yogurt fermentation and the analysis techniques, both instrumental and sensory, for quantifying the volatile compounds in yogurt. The volatile compounds that have been identified in plain yogurt are summarized, with the few key aroma compounds described in detail. Most flavor compounds in yogurt are produced from lipolysis of milkfat and microbiological transformations of lactose and citrate. More than 100 volatiles, including carbonyl compounds, alcohols, acids, esters, hydrocarbons, aromatic compounds, sulfur-containing compounds, and heterocyclic compounds, are found in yogurt at low to trace concentrations. Besides lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone contribute most to the typical aroma and flavor of yogurt. Extended storage of yogurt causes off-flavor development, which is mainly attributed to the production of undesired aldehydes and fatty acids during lipid oxidation. Further work on studying the volatile flavor compounds-matrix interactions, flavor release mechanisms, and the synergistic effect of flavor compounds, and on correlating the sensory properties of yogurt with the compositions of volatile flavor compounds are needed to fully elucidate yogurt aroma and flavor.

DEVELOPMENT OF IMPROVED TITANIUM ORGANIC COMPOUNDS FOR USE AS HYDRAULIC FLUIDS

DTIC Science & Technology

HYDRAULIC FLUIDS, *METALORGANIC COMPOUNDS, *TITANATES, *TITANIUM COMPOUNDS, ALKYL RADICALS, CATALYSTS , CHLORIDES, COMPLEX COMPOUNDS, FLUIDS, PHOSPHORIC ACIDS, PROPYL RADICALS, VISCOSITY, ZINC COMPOUNDS

Understanding the mental lexicon through neglect dyslexia: a study on compound noun reading.

PubMed

Marelli, Marco; Aggujaro, Silvia; Molteni, Franco; Luzzatti, Claudio

2013-04-01

The present study employs neglect dyslexia (ND) as an experimental model to study compound-word processing; in particular, it investigates whether compound constituents are hierarchically organized at mental level and addresses the possibility of whole-word representation. Seven Italian-speaking patients suffering from ND participated in a word naming task. Both left-headed (pescespada, swordfish) and right-headed (astronave, spaceship) Italian compound nouns were used as stimuli. Non-existent compounds, which were generated by substituting the leftmost constituent of a compound with an orthographically similar word (e.g., *pestespada, *plaguesword), were also employed. A significant headedness effect emerged in the group analysis: patients read left-headed compounds better than right-headed compounds. A significant lexicality effect was also found: the participants read real compounds better than their non-existent compound pairs. Moreover, logit mixed-effects analyses indicated a left-hand constituent frequency effect. Results are discussed in terms of hierarchical representation of compounds and direct access to compound lemma nodes.

Clandestine grave detector

DOEpatents

Andrews, Jr., William H.; Thompson, Cyril V [Knoxville, TN; Vass, Arpad A [Oak Ridge, TN; Smith, Rob R [Knoxville, TN

2011-12-13

An apparatus and a method for detecting a burial site of human remains are disclosed. An air stream is drawn through an air intake conduit from locations near potential burial sites of human remains. The air stream is monitored by one or more chemical sensors to determine whether the air stream includes one or more indicator compounds selected from halogenated compounds, hydrocarbons, nitrogen-containing compounds, sulfur-containing compounds, acid/ester compounds, oxygen-containing compounds, and naphthalene-containing compounds. When it is determined that an indicator compound is present in the air stream, this indicates that a burial site of human remains is below or nearby. Each sensor may be in electrical communication with an indicator that signals when the sensor has detected the presence of the indicator compound in the air stream. In one form, the indicator compound is a halogenated compound and/or a hydrocarbon, and the presence of the halogenated compound and/or the hydrocarbon in the air stream indicates that a burial site of human remains is below or nearby.

[Studies on metabolites from marine microorganism Aspergillus terreus collected from nature reserve region of mangrove].

PubMed

Shen, Yi; Zou, Jianhua; Dai, Jungui

2011-09-01

To search for new antitumor active lead compounds from marine microorganism. A marine strain, Aspergillus terreus, was cultured and up-scaled in artificial seawater media, from which the metabolites were isolated and elucidated by using modern spectroscopy techniques. Twelve compounds were isolated from mycelia and fermentation broth of A. terreus. Compounds 1-4 were steroids, compounds 5-8 were organic acids and esters, compound 9 was an alkaloid, compound 10 was an isocoumarin, compound 11 was ceramide, compound 12 was propenyl cyclic pentanediol.

Basics of compounding: Tips and hints: powders, capsules, tablets, suppositories, and sticks, part 1.

PubMed

Allen, Loyd V

2014-01-01

No matter the profession, professionals should never stop learning. This is especially true and important in the profession of compounding pharmacy. Compounding pharmacists are continuously faced with the challenge of finding new and inventive ways to assist patients with their individual and specific drug requirements. As compounding pharmacists learn, be it through formal continuing education or experience, they should be willing to share their knowledge with other compounders. In our goal of providing compounding pharmacists with additional knowledge to improve their skills in the art and practice of compounding, this article, which provides tips and hits on compounding with powders, capsules, tablets, suppositories, and sticks, represents the first in a series of articles to assist compounding pharmacists in the preparation of compounded medications.

Design and synthesis of aloe-emodin derivatives as potent anti-tyrosinase, antibacterial and anti-inflammatory agents.

PubMed

Liu, Jinbing; Wu, Fengyan; Chen, Changhong

2015-11-15

Twenty aloe-emodin derivatives were designed, synthesized, and their biological activities were evaluated. Some compounds displayed potent tyrosinase inhibitory activities, especially, compounds with thiosemicarbazide moiety showed more potent inhibitory effects than the other compounds. The structure-activity relationships (SARs) were preliminarily discussed. The inhibition mechanism of selected compounds 1 and 13 were investigated. The results showed compound 1 was reversible inhibitor, however, compound 13 was irreversible. Kinetic analysis indicated that compound 1 was competitive tyrosinase inhibitor. Furthermore, the antibacterial activities and anti-inflammatory activities of some selected compounds were also screened. The results showed that compound 3 exhibited more potent antibacterial activity than the aloe-emodin, compounds 5 and 6 possessed more potent anti-inflammatory activities than the diacerein. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Detection of organic compounds on Mars].

PubMed

Kobayashi, K

1997-03-01

McKay et al. detected polycyclic aromatic hydrocarbons (PAHs) in Martian meteorite ALH 84001 by two-step laser mass spectrometry. From the presence of PAHs, together with other results, they concluded that there were past life of Mars. On the other hands, no organisms nor organic compounds were detected in Martian regolith in Viking experiments in 1976. In order to obtain solid evidence for organisms or bioorganic compounds compounds on Mars, further analyses of Martian samples are required. There may be four classes of organic compounds on Mars, which are (i) organic compounds abiotically formed from primitive Mars atmosphere, (ii) Organic compounds delivered out of Mars, (iii) Organic compounds biotically formed by Mars organisms, and (iv) Organic compounds abiotically formed from the present Mars atmosphere. Possible organic compounds on Mars and analytical methods for them are discussed.

ION COMPOSITION ELUCIDATION (ICE): A HIGH ...

EPA Pesticide Factsheets

Unidentified Organic Compounds. For target analytes, standards are purchased, extraction and clean-up procedures are optimized, and mass spectra and retention times for the chromatographic separation are obtained for comparison to the target compounds in environmental sample extracts. This is an efficient approach and selective extraction and clean-up can decrease detection limits for the target compounds relative to analyzing a raw extract containing compounds that yield mass interferences. But selection of a class of compounds for study ignores many potentially toxic compounds. All compounds should be considered, because even trace amounts of compounds found to be endocrine disrupting chemicals might influence embryonic development. Before the toxicology of the hundreds of compounds found in sewage treatment effluents and water reservoirs can be studied alone and in mixtures, they must first be identified. A given compound might be one of the 3800 high production volume chemicals used commercially, a human or microorganism metabolite of such a compound, a photochemical degradation, hydrolysis, or thermal decomposition product, a chlorination or ozonolysis byproduct for drinking water samples, or a naturally occurring compound. Numerous researchers targeting assorted classes of analytes could easily overlook or be unable to identify many of these compounds. Most non-targeted compounds will not be in mass spectral libraries and can seldom be tentatively identifi

Defense Technical Information Center Thesaurus

DTIC Science & Technology

2000-10-01

acquisition radar 4 + Indicates existence of further generic levels of the term DTIC Thesaurus Actuators Acridines Actinide series (cont.) Activated sintering...BT Heterocyclic compounds+ Uranium+ BT Sintering Acrilan Actinide series compounds Activated sludge process use Acrylonitrile polymers RT Actinide...Waste treatment+ Protactinium compounds Acronyms Thorium compounds+ Activation use Abbreviations Transuranium compounds+ UF Energizing Uranium compounds

A kinase-focused compound collection: compilation and screening strategy.

PubMed

Sun, Dongyu; Chuaqui, Claudio; Deng, Zhan; Bowes, Scott; Chin, Donovan; Singh, Juswinder; Cullen, Patrick; Hankins, Gretchen; Lee, Wen-Cherng; Donnelly, Jason; Friedman, Jessica; Josiah, Serene

2006-06-01

Lead identification by high-throughput screening of large compound libraries has been supplemented with virtual screening and focused compound libraries. To complement existing approaches for lead identification at Biogen Idec, a kinase-focused compound collection was designed, developed and validated. Two strategies were adopted to populate the compound collection: a ligand shape-based virtual screening and a receptor-based approach (structural interaction fingerprint). Compounds selected with the two approaches were cherry-picked from an existing high-throughput screening compound library, ordered from suppliers and supplemented with specific medicinal compounds from internal programs. Promising hits and leads have been generated from the kinase-focused compound collection against multiple kinase targets. The principle of the collection design and screening strategy was validated and the use of the kinase-focused compound collection for lead identification has been added to existing strategies.

Isolation, identification and antioxidant activity of bound phenolic compounds present in rice bran.

PubMed

Wang, Wei; Guo, Jia; Zhang, Junnan; Peng, Jie; Liu, Tianxing; Xin, Zhihong

2015-03-15

The bound phenolic compounds in rice bran were released and extracted with ethyl acetate based on alkaline digestion. An investigation of the chemical constituents of EtOAc extract has led to the isolation of a new compound, para-hydroxy methyl benzoate glucoside (8), together with nine known compounds, cycloeucalenol cis-ferulate (1), cycloeucalenol trans-ferulate (2), trans-ferulic acid (3), trans-ferulic acid methyl ester (4), cis-ferulic acid (5), cis-ferulic acid methyl ester (6), methyl caffeate (7), vanillic aldehyde (9) and para-hydroxy benzaldehyde (10). The structures of these compounds were determined using a combination of spectroscopic methods and chemical analysis. Among the compounds isolated, compound 3, 5 and 7 exhibited strong DPPH and ABTS(+) radical scavenging activities, followed by compounds 4 and 6. Compound 1 and 2 showed potent DPPH and ABTS(+) radical scavenging activities, compound 8 displayed moderate antioxidant activity against ABTS(+) radical, whereas compound 9 and 10 showed weak antioxidant activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Polymers containing borane or carborane cage compounds and related applications

DOEpatents

Bowen, III, Daniel E; Eastwood, Eric A

2013-04-23

Polymers comprising residues of cage compound monomers having at least one polyalkoxy silyl substituent are provided. The cage compound monomers are selected from borane cage compound monomers comprising at least 7 cage atoms and/or carborane cage compound monomers comprising 7 to 11 cage compound monomers. Such polymers can further comprise one or more reactive matrices and/or co-monomers covalently bound with the cage compound monomer residues. Articles of manufacture comprising such polymers are also disclosed.

Word Syntax of Nominal Compounds: Internal and Aphasiological Evidence from Turkish

ERIC Educational Resources Information Center

Tat, Deniz

2013-01-01

This dissertation is an analysis of two types of nominal compounds in Turkish, primary compounds and synthetic compounds within the framework of Distributed Morphology. A nominal primary compound is formed by two nouns, and its meaning is largely determined by world knowledge. A synthetic compound, on the other hand, is formed by a noun and a…

Formulations for neutralization of chemical and biological toxants

DOEpatents

Tadros, Maher E.; Tucker, Mark D.

2003-05-20

A formulation and method of making that neutralizes the adverse health effects of both chemical and biological compounds, especially chemical warfare (CW) and biological warfare (BW) agents. The formulation of the present invention non-toxic and non-corrosive and can be delivered by a variety of means and in different phases. The formulation provides solubilizing compounds that serve to effectively render the chemical and biological compounds, particularly CW and BW compounds, susceptible to attack and at least one reactive compound that serves to attack (and detoxify or kill) the compound. The at least one reactive compound can be an oxidizing compound, a nucleophilic compound or a mixture of both. The formulation can kill up to 99.99999% of bacterial spores within one hour of exposure.

Therapeutic Phytogenic Compounds for Obesity and Diabetes

PubMed Central

Jung, Hee Soong; Lim, Yun; Kim, Eun-Kyoung

2014-01-01

Natural compounds have been used to develop drugs for many decades. Vast diversities and minimum side effects make natural compounds a good source for drug development. However, the composition and concentrations of natural compounds can vary. Despite this inconsistency, half of the Food and Drug Administration (FDA)-approved pharmaceuticals are natural compounds or their derivatives. Therefore, it is essential to continuously investigate natural compounds as sources of new pharmaceuticals. This review provides comprehensive information and analysis on natural compounds from plants (phytogenic compounds) that may serve as anti-obesity and/or anti-diabetes therapeutics. Our growing understanding and further exploration of the mechanisms of action of the phytogenic compounds may afford opportunities for development of therapeutic interventions in metabolic diseases. PMID:25421245

Dehydrogenation of liquid fuel in microchannel catalytic reactor

DOEpatents

Toseland, Bernard Allen; Pez, Guido Peter; Puri, Pushpinder Singh

2010-08-03

The present invention is an improved process for the storage and delivery of hydrogen by the reversible hydrogenation/dehydrogenation of an organic compound wherein the organic compound is initially in its hydrogenated state. The improvement in the route to generating hydrogen is in the dehydrogenation step and recovery of the dehydrogenated organic compound resides in the following steps: introducing a hydrogenated organic compound to a microchannel reactor incorporating a dehydrogenation catalyst; effecting dehydrogenation of said hydrogenated organic compound under conditions whereby said hydrogenated organic compound is present as a liquid phase; generating a reaction product comprised of a liquid phase dehydrogenated organic compound and gaseous hydrogen; separating the liquid phase dehydrogenated organic compound from gaseous hydrogen; and, recovering the hydrogen and liquid phase dehydrogenated organic compound.

Dehydrogenation of liquid fuel in microchannel catalytic reactor

DOEpatents

Toseland, Bernard Allen [Allentown, PA; Pez, Guido Peter [Allentown, PA; Puri, Pushpinder Singh [Emmaus, PA

2009-02-03

The present invention is an improved process for the storage and delivery of hydrogen by the reversible hydrogenation/dehydrogenation of an organic compound wherein the organic compound is initially in its hydrogenated state. The improvement in the route to generating hydrogen is in the dehydrogenation step and recovery of the dehydrogenated organic compound resides in the following steps: introducing a hydrogenated organic compound to a microchannel reactor incorporating a dehydrogenation catalyst; effecting dehydrogenation of said hydrogenated organic compound under conditions whereby said hydrogenated organic compound is present as a liquid phase; generating a reaction product comprised of a liquid phase dehydrogenated organic compound and gaseous hydrogen; separating the liquid phase dehydrogenated organic compound from gaseous hydrogen; and, recovering the hydrogen and liquid phase dehydrogenated organic compound.

History of sterile compounding in U.S. hospitals: learning from the tragic lessons of the past.

PubMed

Myers, Charles E

2013-08-15

The evolution of sterile compounding in the context of hospital patient care, the evolution of related technology, past incidents of morbidity and mortality associated with preparations compounded in various settings, and efforts over the years to improve compounding practices are reviewed. Tightened United States Pharmacopeial Convention standards (since 2004) for sterile compounding made it difficult for hospitals to achieve all of the sterile compounding necessary for patient care. Shortages of manufactured injections added to the need for compounding. Non-hospital-based compounding pharmacies increased sterile compounding to meet the needs. Gaps in federal and state laws and regulations about compounding pharmacies led to deficiencies in their regulation. Lapses in sterility led to injuries and deaths. Perspectives offered include potential actions, including changes in practitioner education, better surveillance of sterile compounding, regulatory reforms, reexamination of the causes of drug shortages, and the development of new technologies. Over the years, there have been numerous exhortations for voluntary better performance in sterile compounding. In addition, professional leadership has been vigorous and extensive in the form of guidance, publications, education, enforceable standards, and development of various associations and organizations dealing with safe compounding practices. Yet problems continue to occur. We must engage in diligent learning from the injuries and tragedies that have occurred. Assuming that we are already doing all we can to avoid problems would be an abdication of the professional mission of pharmacists. It would be wrong thinking to assume that the recent problems in large-scale compounding pharmacies are the only problems that warrant attention. It is time for a systematic assessment of the nature and the dimensions of the problems in every type of setting where sterile compounding occurs. It also is time for some innovative thinking about ensuring safety in sterile compounding.

Organic compounds in produced waters from coalbed natural gas wells in the Powder River Basin, Wyoming, USA

USGS Publications Warehouse

Orem, W.H.; Tatu, C.A.; Lerch, H.E.; Rice, C.A.; Bartos, T.T.; Bates, A.L.; Tewalt, S.; Corum, M.D.

2007-01-01

The organic composition of produced water samples from coalbed natural gas (CBNG) wells in the Powder River Basin, WY, sampled in 2001 and 2002 are reported as part of a larger study of the potential health and environmental effects of organic compounds derived from coal. The quality of CBNG produced waters is a potential environmental concern and disposal problem for CBNG producers, and no previous studies of organic compounds in CBNG produced water have been published. Organic compounds identified in the produced water samples included: phenols, biphenyls, N-, O-, and S-containing heterocyclic compounds, polycyclic aromatic hydrocarbons (PAHs), aromatic amines, various non-aromatic compounds, and phthalates. Many of the identified organic compounds (phenols, heterocyclic compounds, PAHs) are probably coal-derived. PAHs represented the group of organic compounds most commonly observed. Concentrations of total PAHs ranged up to 23 ??g/L. Concentrations of individual compounds ranged from about 18 to <0.01 ??g/L. Temporal variability of organic compound concentrations was documented, as two wells with relatively high organic compound contents in produced water in 2001 had much lower concentrations in 2002. In many areas, including the PRB, coal strata provide aquifers for drinking water wells. Organic compounds observed in produced water are also likely present in drinking water supplied from wells in the coal. Some of the organic compounds identified in the produced water samples are potentially toxic, but at the levels measured in these samples are unlikely to have acute health effects. The human health effects of low-level, chronic exposure to coal-derived organic compounds in drinking water are currently unknown. Continuing studies will evaluate possible toxic effects from low level, chronic exposure to coal-derived organic compounds in drinking water supplies.

Mutagenic Azo Dyes, Rather Than Flame Retardants, Are the Predominant Brominated Compounds in House Dust.

PubMed

Peng, Hui; Saunders, David M V; Sun, Jianxian; Jones, Paul D; Wong, Chris K C; Liu, Hongling; Giesy, John P

2016-12-06

Characterization of toxicological profiles by use of traditional targeted strategies might underestimate the risk of environmental mixtures. Unbiased identification of prioritized compounds provides a promising strategy for meeting regulatory needs. In this study, untargeted screening of brominated compounds in house dust was conducted using a data-independent precursor isolation and characteristic fragment (DIPIC-Frag) approach, which used data-independent acquisition (DIA) and a chemometric strategy to detect peaks and align precursor ions. A total of 1008 brominated compound peaks were identified in 23 house dust samples. Precursor ions and formulas were identified for 738 (73%) of the brominated compounds. A correlation matrix was used to cluster brominated compounds; three large groups were found for the 140 high-abundance brominated compounds, and only 24 (17%) of these compounds were previously known flame retardants. The predominant class of unknown brominated compounds was predicted to consist of nitrogen-containing compounds. Following further validation by authentic standards, these compounds (56%) were determined to be novel brominated azo dyes. The mutagenicity of one major component was investigated, and mutagenicity was observed at environmentally relevant concentrations. Results of this study demonstrated the existence of numerous unknown brominated compounds in house dust, with mutagenic azo dyes unexpectedly being identified as the predominant compounds.

Functional Group Analysis.

ERIC Educational Resources Information Center

Smith, Walter T., Jr.; Patterson, John M.

1984-01-01

Literature on analytical methods related to the functional groups of 17 chemical compounds is reviewed. These compounds include acids, acid azides, alcohols, aldehydes, ketones, amino acids, aromatic hydrocarbons, carbodiimides, carbohydrates, ethers, nitro compounds, nitrosamines, organometallic compounds, peroxides, phenols, silicon compounds,…

Applying Quality by Design Concepts to Pharmacy Compounding.

PubMed

Timko, Robert J

2015-01-01

Compounding of medications is an important part of the practice of the pharmacy profession. Because compounded medications do not have U.S. Food and Drug Administration approval, a pharmacist has the responsibility to ensure that compounded medications are of suitable quality, safety, and efficacy. The Federal Government and numerous states have updated their laws and regulations regarding pharmacy compounding as a result of recent quality issues. Compounding pharmacists are expected to follow good preparation prodecures in their compounding practices in much the same way pharmaceutical manufacturers are required to follow Current Good Manufacturing Procedures as detailed in the United States Code of Federal Regulations. Application of Quality by Design concepts to the preparation process for a compounded medication can help in understanding the potential pitfalls and the means to mitigate their impact. The goal is to build quality into the compounding process to ensure that the resultant compounded prescription meets the human or animal patients' requirements.

Chemistry WebBook

National Institute of Standards and Technology Data Gateway

SRD 69 NIST Chemistry WebBook (Web, free access)   The NIST Chemistry WebBook contains: Thermochemical data for over 7000 organic and small inorganic compounds; thermochemistry data for over 8000 reactions; IR spectra for over 16,000 compounds; mass spectra for over 33,000 compounds; UV/Vis spectra for over 1600 compounds; electronic and vibrational spectra for over 5000 compounds; constants of diatomic molecules(spectroscopic data) for over 600 compounds; ion energetics data for over 16,000 compounds; thermophysical property data for 74 fluids.

The nature of compounds: a psychocentric perspective.

PubMed

Libben, Gary

2014-01-01

Although compound words often seem to be words that themselves contain words, this paper argues that this is not the case for the vast majority of lexicalized compounds. Rather, it is claimed that as a result of acts of lexical processing, the constituents of compound words develop into new lexical representations. These representations are bound to specific morphological roles and positions (e.g., head, modifier) within a compound word. The development of these positionally bound compound constituents creates a rich network of lexical knowledge that facilitates compound processing and also creates some of the well-documented patterns in the psycholinguistic and neurolinguistic study of compounding.

Veterinary Compounding: Regulation, Challenges, and Resources

PubMed Central

Davidson, Gigi

2017-01-01

The spectrum of therapeutic need in veterinary medicine is large, and the availability of approved drug products for all veterinary species and indications is relatively small. For this reason, extemporaneous preparation, or compounding, of drugs is commonly employed to provide veterinary medical therapies. The scope of veterinary compounding is broad and focused primarily on meeting the therapeutic needs of companion animals and not food-producing animals in order to avoid human exposure to drug residues. As beneficial as compounded medical therapies may be to animal patients, these therapies are not without risks, and serious adverse events may occur from poor quality compounds or excipients that are uniquely toxic when administered to a given species. Other challenges in extemporaneous compounding for animals include significant regulatory variation across the global veterinary community, a relative lack of validated compounding formulas for use in animals, and poor adherence by compounders to established compounding standards. The information presented in this article is intended to provide an overview of the current landscape of compounding for animals; a discussion on associated benefits, risks, and challenges; and resources to aid compounders in preparing animal compounds of the highest possible quality. PMID:28075379

Influence of mastication rate on dynamic flavour release analysed by combined model mouth/proton transfer reaction-mass spectrometry

NASA Astrophysics Data System (ADS)

van Ruth, Saskia M.; Buhr, Katja

2004-12-01

The influence of mastication rate on the dynamic release of seven volatile flavour compounds from sunflower oil was evaluated by combined model mouth/proton transfer reaction-mass spectrometry (PTR-MS). Air/oil partition coefficients were measured by static headspace gas chromatography. The dynamic release of the seven volatile flavour compounds from sunflower oil was significantly affected by the compounds' hydrophobicity and the mastication rate employed in the model mouth. The more hydrophobic compounds were released at a higher rate than their hydrophilic counterparts. Increase in mastication rate increased the maximum concentration measured by 36% on average, and the time to reach this maximum by 35% on average. Mastication affected particularly the release of the hydrophilic compounds. The maximum concentration of the compounds correlated significantly with the compounds' air/oil partition coefficients. The initial release rates over the first 15 s were affected by the type of compound, but not by the mastication rate. During the course of release, the proportions of the hydrophilic compounds to the overall flavour mixture in air decreased. The contribution of the hydrophobic compounds increased. Higher mastication rates, however, increased the proportions of the hydrophilic compounds and decreased those of the hydrophobic compounds.

Surface-water-quality assessment of the Yakima River basin, Washington; distribution of pesticides and other organic compounds in water, sediment, and aquatic biota, 1987-91; with a section on dissolved organic carbon in the Yakima River basin

USGS Publications Warehouse

Rinella, Joseph F.; McKenzie, Stuart W.; Crawford, J. Kent; Foreman, William T.; Fuhrer, Gregory J.; Morace, Jennifer L.; Aiken, George R.

1999-01-01

During 1987-91, chemical data were collected for pesticides and other organic compounds in surface water, streambed sediment, suspended sediment, agricultural soil, and aquatic biota to determine the occurrence, distribution, transport, and fate of organic compounds in the Yakima River basin in Washington. The report describes the chemical and physical properties of the compounds most frequently detected in the water column; organochlorine compounds including DDT, organophosphorus compounds, thiocarbamate and sulfite compounds, acetamide and triazine compounds, and chlorophenoxy-acetic acid and benzoic compounds. Concentrations are evaluated relative to chronic-toxicity water quality criteria and guidelines for the protection of human health and freshwater aquatic life.

Phenethyl ester and amide of Ferulic Acids: Synthesis and bioactivity against P388 Leukemia Murine Cells

NASA Astrophysics Data System (ADS)

Firdaus; Soekamto, N. H.; Seniwati; Islam, M. F.; Sultan

2018-03-01

Bioactivity of a compound is closely related to the molecular structure of the compound concerned, its strength being the quantitative relation of the strength of the activity of the group it possesses. The combining of moieties of the active compounds will produce more active compounds. Most phenolic compounds as well as compounds containing moiety phenethyl groups have potential activity as anticancer. Combining phenolic groups and phenethyl groups in a compound will result in compounds having strong anticancer bioactivity. This study aims to combine the feruloyl and phenethyl groups to form esters and amides by synthesize of phenethyl trans-3-(4-hydroxy-3-methoxyphenyl)acrylate (5) and trans-3-(4- hydroxy-3-methoxyphenyl)-N-phenethylacrylamide (6) from ferulic acid with phenethyl alcohol and phenethylamine, and to study their bioactivity as anticancer. The synthesis of both compounds was conducted via indirect reaction, including acetylation, chlorination, esterfication/amidation, and deacetylation. Structures of products were characterized by FTIR and NMR data, and their bioactivity assay of the compounds against P388 Leukemia Murine Cells was conducted by an MTT method. Results showed that the compound 5 was obtained as a yellow gel with the IC50 of 10.79 μg/mL (36.21 μΜ), and the compound 6 was a yellowish solid with a melting point of 118-120°C and the IC50 of 29.14 μg/mL (97.79 μΜ). These compounds were more active than the analog compounds.

Encapsulation of bioactive compound from extracted jasmine flower using β-Cyclodextrin via electrospray

NASA Astrophysics Data System (ADS)

Rahmam., S.; Naim., M. N.; Ng., E.; Mokhtar, M. Nn; Abu Bakar, N. F.

2016-06-01

The ability of electrospray to encapsulate the bioactive compound extracted from Jasmine flower with β-Cyclodextrion (β-CD) without any thermal-assisted processing was demonstrated in this study. The extraction of Jasmine compound were conducted using sonicator at 70 000 Hz, for 10 minutes and followed by mixing of the filtered compound with β-CD. Then, the mixture was electrosprayed under a stable Taylor cone jet mode at the voltage of 4 - 5 kV, with flow rate of 0.2 ml/hour. The aluminum substrate that used for collecting the deposit was placed at 30 cm from the needle's tip to allow the occurrence of evaporation and droplet fission until the droplet transform to solid particles. Characteristics of solidified bioactive compound from Jasmine flower (non-encapsulated compound) and solidified bioactive compound with β-CD (encapsulated compound) were studied in this work. From SEM images, it can be observed that the particles size distribution of encapsulated compound deposits have better deposition array and did not aggregate with each other compared to the non-encapsulated compound. FE-SEM images of encapsulated compound deposits indicate more solid crystal looks while non-encapsulated compound was obtained in the porous form. The electrospray process in this work has successfully encapsulated the Jasmine compound with β-CD without any thermal-assisted process. The encapsulation occurrence was determined using FTIR analysis. Identical peaks that referred to the β-CD were found on the encapsulated compound demonstrated that most deposits were encapsulated with β-CD.

Compound C induces protective autophagy in human cholangiocarcinoma cells via Akt/mTOR-independent pathway.

PubMed

Zhao, Xiaofang; Luo, Guosong; Cheng, Ying; Yu, Wenjing; Chen, Run; Xiao, Bin; Xiang, Yuancai; Feng, Chunhong; Fu, Wenguang; Duan, Chunyan; Yao, Fuli; Xia, Xianming; Tao, Qinghua; Wei, Mei; Dai, Rongyang

2018-07-01

Compound C, a well-known inhibitor of AMP-activated protein kinase (AMPK), has been reported to exert antitumor activities in some types of cells. Whether compound C can exert antitumor effects in human cholangiocarcinoma (CCA) remains unknown. Here, we demonstrated that compound C is a potent inducer of cell death and autophagy in human CCA cells. Autophagy inhibitors increased the cytotoxicity of compound C towards human CCA cells, as confirmed by increased LDH release, and PARP cleavage. It is notable that compound C treatment increased phosphorylated Akt, sustained high levels of phosphorylated p70S6K, and decreased mTOR regulated p-ULK1 (ser757). Based on the data that blocking PI3K/Akt or mTOR had no apparent influence on autophagic response, we suggest that compound C induces autophagy independent of Akt/mTOR signaling in human CCA cells. Further study demonstrated that compound C inhibited the phosphorylation of JNK and its target c-Jun. Blocking JNK by SP600125 or siRNA suppressed autophagy induction upon compound C treatment. Moreover, compound C induced p38 MAPK activation, and its inhibition promoted autophagy induction via JNK activation. In addition, compound C induced p53 expression, and its inhibition attenuated compound C-induced autophagic response. Thus, compound C triggers autophagy, at least in part, via the JNK and p53 pathways in human CCA cells. In conclusion, suppresses autophagy could increase compound C sensitivity in human CCA. © 2018 Wiley Periodicals, Inc.

Characterization of ToxCast Phase II compounds disruption of ...

EPA Pesticide Factsheets

The development of multi-well microelectrode array (mwMEA) systems has increased in vitro screening throughput making them an effective method to screen and prioritize large sets of compounds for potential neurotoxicity. In the present experiments, a multiplexed approach was used to determine compound effects on both neural function and cell health in primary cortical networks grown on mwMEA plates following exposure to ~1100 compounds from EPA’s Phase II ToxCast libraries. On DIV 13, baseline activity (40 min) was recorded prior to exposure to each compound at 40 µM. DMSO and the GABAA antagonist bicuculline (BIC) were included as controls on each mwMEA plate. Changes in spontaneous network activity (mean firing rate; MFR) and cell viability (lactate dehydrogenase; LDH and CellTiter Blue; CTB) were assessed within the same well following compound exposure. Activity calls (“hits”) were established using the 90th and 20th percentiles of the compound-induced change in MFR (medians of triplicates) across all tested compounds; compounds above (top 10% of compounds increasing MFR), and below (bottom 20% of compounds decreasing MFR) these thresholds, respectively were considered hits. MFR was altered beyond one of these thresholds by 322 compounds. Four compound categories accounted for 66% of the hits, including: insecticides (e.g. abamectin, lindane, prallethrin), pharmaceuticals (e.g. haloperidol, reserpine), fungicides (e.g. hexaconazole, fenamidone), and h

Combination of cheminformatics and bioinformatics to explore the chemical basis of the rhizomes and aerial parts of Dioscorea nipponica Makino.

PubMed

Li, Xu-Zhao; Zhang, Shuai-Nan; Yang, Xu-Yan

2017-12-01

This study was aimed to explore the chemical basis of the rhizomes and aerial parts of Dioscorea nipponica Makino (DN). The pharmacokinetic profiles of the compounds from DN were calculated via ACD/I-Lab and PreADMET program. Their potential therapeutic and toxicity targets were screened through the DrugBank's or T3DB's ChemQuery structure search. Eleven of 48 compounds in the rhizomes and over half of the compounds in the aerial parts had moderate or good human oral bioavailability. Twenty-three of 48 compounds in the rhizomes and 40/43 compounds from the aerial parts had moderate or good permeability to intestinal cells. Forty-three of 48 compounds from the rhizomes and 18/43 compounds in the aerial parts bound weakly to the plasma proteins. Eleven of 48 compounds in the rhizomes and 36/43 compounds of the aerial parts might pass across the blood-brain barrier. Forty-three 48 compounds in the rhizomes and 18/43 compounds from the aerial parts showed low renal excretion ability. The compounds in the rhizomes possessed 391 potential therapeutic targets and 216 potential toxicity targets. Additionally, the compounds from the aerial parts possessed 101 potential therapeutic targets and 183 potential toxicity targets. These findings indicated that combination of cheminformatics and bioinformatics may facilitate achieving the objectives of this study. © 2017 Royal Pharmaceutical Society.

Competition between the compound and the pre-compound emission processes in α-induced reactions at near astrophysical energy to well above it

NASA Astrophysics Data System (ADS)

Sharma, Manoj Kumar; Sharma, Vijay Raj; Yadav, Abhiskek; Singh, Pushpendra P.; Singh, B. P.; Prasad, R.

2016-04-01

The study of pre-compound emission in α-induced reactions, particularly at the low incident energies, is of considerable interest as the pre-compound emission is more likely to occur at higher energies. With a view to study the competition between the compound and the pre-compound emission processes in α-induced reactions at different energies and with different targets, a systematics for neutron emission channels in targets 51V, 55Mn, 93Nb, 121, 123Sb and 141Pr at energy ranging from astrophysical interest to well above it, has been developed. The off-line γ-ray-spectrometry based activation technique has been adopted to measure the excitation functions. The experimental excitation functions have been analysed within the framework of the compound nucleus mechanism based on the Weisskopf-Ewing model and the pre-compound emission calculations based on the geometry dependent hybrid model. The analysis of the data shows that experimental excitation functions could be reproduced only when the pre-compound emission, simulated theoretically, is taken into account. The strength of pre-compound emission process for each system has been obtained by deducing the pre-compound fraction. Analysis of data indicates that in α-induced reactions, the pre-compound emission process plays an important role, particularly at the low incident energies, where the pure compound nucleus process is likely to dominate.

Gaussian versus flat-top spatial beam profiles for optical stimulation of the prostate nerves

NASA Astrophysics Data System (ADS)

Tozburun, Serhat; Lagoda, Gwen A.; Burnett, Arthur L.; Fried, Nathaniel M.

2010-02-01

The cavernous nerves (CN) course along the prostate surface and are responsible for erectile function. Improved identification and preservation of the CN's is critical to maintaining sexual potency after prostate cancer surgery. Noncontact optical nerve stimulation (ONS) of the CN's was recently demonstrated in a rat model, in vivo, as a potential alternative to electrical nerve stimulation (ENS) for identification of the CN's during prostate surgery. However, the therapeutic window for ONS is narrow, so optimal design of the fiber optic delivery system is critical for safe, reproducible stimulation. This study describes modeling, assembly, and testing of an ONS probe for delivering a small, collimated, flat-top laser beam for uniform CN stimulation. A direct comparison of the magnitude and response time of the intracavernosal pressure (ICP) for both Gaussian and flat-top spatial beam profiles was performed. Thulium fiber laser radiation (λ=1870 nm) was delivered through a 200-μm fiber, with distal fiber tip chemically etched to convert a Gaussian to flat-top beam profile. The laser beam was collimated to a 1-mm-diameter spot using an aspheric lens. Computer simulations of light propagation were used to optimize the probe design. The 10-Fr (3.4-mm-OD) laparoscopic probe provided a constant radiant exposure at the CN surface. The probe was tested in four rats, in vivo. ONS of the CN's was performed with a 1-mm-diameter spot, 5-ms pulse duration, and pulse rate of 20 Hz for a duration of 15-30 s. The flat-top laser beam profile consistently produced a faster and higher ICP response at a lower radiant exposure than the Gaussian beam profile due, in part, to easier alignment of the more uniform beam with nerve. The threshold for ONS was approximately 0.14 J/cm2, corresponding to a temperature increase of 6-8°C at the CN surface after a stimulation time of 15 s. With further development, ONS may be used as a diagnostic tool for identification of CN's during prostate cancer surgery.

Ultrahigh-brightness, spectrally-flat, short-wave infrared supercontinuum source for long-range atmospheric applications.

PubMed

Yin, Ke; Zhu, Rongzhen; Zhang, Bin; Jiang, Tian; Chen, Shengping; Hou, Jing

2016-09-05

Fiber based supercontinuum (SC) sources with output spectra covering the infrared atmospheric window are very useful in long-range atmospheric applications. It is proven that silica fibers can support the generation of broadband SC sources ranging from the visible to the short-wave infrared region. In this paper, we present the generation of an ultrahigh-brightness spectrally-flat 2-2.5 μm SC source in a cladding pumped thulium-doped fiber amplifier (TDFA) numerically and experimentally. The underlying physical mechanisms behind the SC generation process are investigated firstly with a numerical model which includes the fiber gain and loss, the dispersive and nonlinear effects. Simulation results show that abundant soliton pulses are generated in the TDFA, and they are shifted towards the long wavelength side very quickly with the nonlinearity of Raman soliton self-frequency shift (SSFS), and eventually the Raman SSFS process is halted due to the silica fiber's infrared loss. A spectrally-flat 2-2.5 μm SC source could be generated as the result of the spectral superposition of these abundant soliton pulses. These simulation results correspond qualitatively well to the following experimental results. Then, in the experiment, a cladding pumped large-mode-area TDFA is built for pursuing a high-power 2-2.5 μm SC source. By enhancing the pump strength, the output SC spectrum broadens to the long wavelength side gradually. At the highest pump power, the obtained SC source has a maximum average power of 203.4 W with a power conversion efficiency of 38.7%. It has a 3 dB spectral bandwidth of 545 nm ranging from 1990 to 2535 nm, indicating a power spectral density in excess of 370 mW/nm. Meanwhile, the output SC source has a good beam profile. This SC source, to the best of our knowledge, is the brightest spectrally-flat 2-2.5 μm light source ever reported. It will be highly desirable in a lot of long-range atmospheric applications, such as broad-spectrum LIDAR, free space communication and hyper-spectral imaging.

Distribution of temperature changes and neurovascular coupling in rat brain following 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") exposure.

PubMed

Coman, Daniel; Sanganahalli, Basavaraju G; Jiang, Lihong; Hyder, Fahmeed; Behar, Kevin L

2015-10-01

(+/-)3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") is an abused psychostimulant that produces strong monoaminergic stimulation and whole-body hyperthermia. MDMA-induced thermogenesis involves activation of uncoupling proteins (UCPs), primarily a type specific to skeletal muscle (UCP-3) and absent from the brain, although other UCP types are expressed in the brain (e.g. thalamus) and might contribute to thermogenesis. Since neuroimaging of brain temperature could provide insights into MDMA action, we measured spatial distributions of systemically administered MDMA-induced temperature changes and dynamics in rat cortex and subcortex using a novel magnetic resonance method, Biosensor Imaging of Redundant Deviation in Shifts (BIRDS), with an exogenous temperature-sensitive probe (thulium ion and macrocyclic chelate 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethyl-1,4,7,10-tetraacetate (DOTMA(4-))). The MDMA-induced temperature rise was greater in the cortex than in the subcortex (1.6 ± 0.4 °C versus 1.3 ± 0.4 °C) and occurred more rapidly (2.0 ± 0.2 °C/h versus 1.5 ± 0.2 °C/h). MDMA-induced temperature changes and dynamics in the cortex and body were correlated, although the body temperature exceeded the cortex temperature before and after MDMA. Temperature, neuronal activity, and blood flow (CBF) were measured simultaneously in the cortex and subcortex (i.e. thalamus) to investigate possible differences of MDMA-induced warming across brain regions. MDMA-induced warming correlated with increases in neuronal activity and blood flow in the cortex, suggesting that the normal neurovascular response to increased neural activity was maintained. In contrast to the cortex, a biphasic relationship was seen in the subcortex (i.e. thalamus), with a decline in CBF as temperature and neural activity rose, transitioning to a rise in CBF for temperature above 37 °C, suggesting that MDMA affected CBF and neurovascular coupling differently in subcortical regions. Considering that MDMA effects on CBF and heat dissipation (as well as potential heat generation) may vary regionally, neuroprotection may require different cooling strategies. Copyright © 2015 John Wiley & Sons, Ltd.

Distribution of temperature changes and neurovascular coupling in rat brain following 3,4-methylenedioxymethamphetamine (MDMA,‘ecstasy’) exposure

PubMed Central

Coman, Daniel; Sanganahalli, Basavaraju G.; Jiang, Lihong; Hyder, Fahmeed; Behar, Kevin L.

2015-01-01

(+/−)3,4-methylenedioxymethamphetamine (MDMA, ‘ecstasy’) is an abused psychostimulant producing strong monoaminergic stimulation and whole-body hyperthermia. MDMA-induced thermogenesis involves activation of uncoupling proteins (UCP), primarily a type specific to skeletal muscle (UCP-3) and which is absent in brain, although other UCP types are expressed in brain (e.g., thalamus) and might contribute to thermogenesis. Since neuroimaging of brain temperature could provide insights of MDMA action, we measured spatial distributions of systemically-administered MDMA-induced temperature changes and dynamics in rat cortex and subcortex using a novel magnetic resonance method, Biosensor Imaging of Redundant Deviation of Shifts (BIRDS), with an exogenous temperature-sensitive probe (thulium ion and macrocyclic chelate 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethyl-1,4,7,10-tetraacetate (DOTMA4−)). The MDMA-induced temperature rise in cortex was greater than in subcortex (1.6±0.4°C vs. 1.3±0.4°C) and occurred more rapidly (2.0±0.2°C/h vs. 1.5±0.2°C/h). MDMA-induced temperature changes and dynamics in cortex and body were correlated, although body temperature exceeded cortex before and after MDMA. Temperature, neuronal activity, and blood flow (CBF) were measured simultaneously in cortex and subcortex (i.e., thalamus) to investigate possible differences of MDMA-induced warming across brain regions. MDMA-induced warming correlated with increases in neuronal activity and blood flow in cortex, suggesting that the normal neurovascular response to increased neural activity was maintained. In contrast to cortex, a biphasic relationship was seen in subcortex (i.e., thalamus), with a decline in CBF as temperature and neural activity rose, transitioning to a rise in CBF for temperature >37°C, suggesting that MDMA affected CBF and neurovascular coupling differently in subcortical regions. Considering that MDMA effects on CBF and heat dissipation (as well as potential heat generation) may vary regionally, neuroprotection may require different cooling strategies. PMID:26286889

A Prospective Randomized Study Comparing Disposable with Reusable Blades for a Morcellator Device.

PubMed

Becker, Benedikt; Orywal, Ann Katrin; Hausmann, Teresa; Gross, Andreas J; Netsch, Christopher

2017-03-01

Transurethral enucleation of the prostate for the management of benign prostatic obstruction (BPO) involves two steps: the enucleation and morcellation procedure. The aim of our study was to assess the efficacy of a morcellator device using disposable and reusable blades with different settings of morcellation speed. A prospective randomized study was initiated for patients with symptomatic BPO undergoing Thulium laser enucleation of the prostate. Mechanical tissue morcellation was performed using the Piranha™ morcellator (R. Wolf, Knittlingen, Germany) with disposable or reusable blades at 850 (n = 24) or 1500 revolutions per minute (rpm) (n = 24). Patient characteristics, intraoperative complications, and the morcellation rate (g/min) were recorded. Data are expressed as median and interquartile range (IQR). Forty-eight patients were randomized using disposable (n = 24) or reusable blades (n = 24). For reusable blades, the morcellation rate did not increase when changing the morcellation speed from 850 to 1500 rpm (5 vs 4.53 g/min, p = 0.843). The morcellation rate increased significantly when changing the morcellation speed from 850 to 1500 rpm using single-use blades (4.77 vs 10 g/min, p ≤ 0.014). The morcellation rate was not different at 850 rpm between reusable and single-use blades (5 vs 4.77 g/min, p = 0.671). Conversely, the morcellation rate was significantly different at 1500 rpm between reusable and single-use blades (4.53 vs 10 g/min, p ≤ 0.017). The total morcellation rate (at 850 and 1500 rpm) was significantly increased using single-use blades compared to reusable blades (7.67 vs 4.8 g/min, p ≤ 0.026). Interestingly, enucleated weight (g) and the morcellation rate (g/min) correlated inversely using single-use blades at 1500 rpm (r = -0.742, p ≤ 0.004). Only one superficial bladder injury occurred at 1500 rpm, which needed no further interventions. The Piranha morcellator facilitates efficient tissue removal with single-use and reusable blades. Disposable morcellator blades increase tissue removal significantly at 1500 rpm.

Retention time of feed particles and liquids in the stomachs and intestines of dairy cows. Direct measurement and calculations based on faecal collection.

PubMed

Mambrini, M; Peyraud, J L

1997-01-01

To validate a method for analysing indigestible marker excretion patterns in terms of digesta passage, the mean retention time (MRT) of long hay, ground hay and concentrate, marked, respectively, with thulium, ytterbium and dysprosium was measured in the total digestive tract (TMRT) and in the stomachs (SMRT) of four cows fed on a diet of hay in the long form (17.7 kg DM/day). The MRT of the particulate and liquid phases in the intestines was obtained after faecal particles labelled by Europium and Chromium EDTA were pulse dosed through the duodenal cannula. Following test meals, total faecal collection and spot sampling of duodenal digesta were performed at fixed intervals. TMRT were 51.7, 45.6, 40.6 h and SMRT were 39.5, 31.9 and 28.0 h, respectively, for hay, ground hay and concentrate. The MRT of the liquids in the rumen (8.7 h) was shorter than the SMRT of particles but there was no differential passage between liquids and particles after the duodenum. Intestinal MRT averaged 11 h and was partitioned into 7.5 and 3.5, respectively, for MRT in the tubular sections and the caecum-proximal colon. The compartmental analysis of the faecal patterns of markers given during a test meal gives the following results. The time associated with the descending part of faecal kinetics (respectively, 25.3 and 22.9 h for hay and concentrate) is directly related to the escape of feed particles from the rumen. The delay of first appearance of markers mostly reflects transit in the post duodenal tubular sections for the concentrate. The time associated with the ascending part (respectively, 16.9 and 9.4 h for hay and concentrate) represents the time required to reduce the size of the forage particles (7 h according to the difference between TMRT of long and ground hay direct measurements) and caecal mixing (3.5 h) as well as other compartments or processes that are not clearly identified.

Room temperature high power mid-IR diode laser bars for atmospheric sensing applications

NASA Astrophysics Data System (ADS)

Crump, Paul; Patterson, Steve; Dong, Weimin; Grimshaw, Mike; Wang, Jun; Zhang, Shiguo; Elim, Sandrio; Bougher, Mike; Patterson, Jason; Das, Suhit; Wise, Damian; Matson, Triston; Balsley, David; Bell, Jake; DeVito, Mark; Martinsen, Rob

2007-04-01

Peak CW optical power from single 1-cm diode laser bars is advancing rapidly across all commercial wavelengths and the available range of emission wavelengths also continues to increase. Both high efficiency ~ 50% and > 100-W power InP-based CW bars have been available in bar format around 1500-nm for some time, as required for eye-safe illuminators and for pumping Er-YAG crystals. There is increasing demand for sources at longer wavelengths. Specifically, 1900-nm sources can be used to pump Holmium doped YAG crystals, to produce 2100-nm emission. Emission near 2100-nm is attractive for free-space communications and range-finding applications as the atmosphere has little absorption at this wavelength. Diode lasers that emit at 2100-nm could eliminate the need for the use of a solid-state laser system, at significant cost savings. 2100-nm sources can also be used as pump sources for Thulium doped solid-state crystals to reach even longer wavelengths. In addition, there are several promising medical applications including dental applications such as bone ablation and medical procedures such as opthamology. These long wavelength sources are also key components in infra-red-counter-measure systems. We have extended our high performance 1500-nm material to longer wavelengths through optimization of design and epitaxial growth conditions and report peak CW output powers from single 1-cm diode laser bars of 37W at 1910-nm and 25W at 2070-nm. 1-cm bars with 20% fill factor were tested under step-stress conditions up to 110-A per bar without failure, confirming reasonable robustness of this technology. Stacks of such bars deliver high powers in a collimated beam suitable for pump applications. We demonstrate the natural spectral width of ~ 18nm of these laser bars can be reduced to < 3-nm with use of an external Volume Bragg Grating, as required for pump applications. We review the developments required to reach these powers, latest advances and prospects for longer wavelength, higher power and higher efficiency.

Atomic layer deposition of highly-doped Er:Al2O3 and Tm:Al2O3 for silicon-based waveguide amplifiers (Conference Presentation)

NASA Astrophysics Data System (ADS)

Roenn, John; Karvonen, Lasse; Pyymäki-Perros, Alexander; Peyghambarian, Nasser; Lipsanen, Harri; Säynätjoki, Antti; Sun, Zhipei

2016-05-01

Recently, rare-earth doped waveguide amplifiers (REDWAs) have drawn significant attention as a promising solution to on-chip amplification of light in silicon photonics and integrated optics by virtue of their high excited state lifetime (up to 10 ms) and broad emission spectrum (up to 200 nm) at infrared wavelengths. In the family of rare-earths, at least erbium, holmium, thulium, neodymium and ytterbium have been demonstrated to be good candidates for amplifier operation at moderate concentrations (< 0.1 %). However, efficient amplifier operation in REDWAs is a very challenging task because high concentration of ions (<0.1%) is required in order to produce reasonable amplification over short device length. Inevitably, high concentration of ions leads to energy-transfer between neighboring ions, which results as decreased gain and increased noise in the amplifier system. It has been shown that these energy-transfer mechanisms in highly-doped gain media are inversely proportional to the sixth power of the distance between the ions. Therefore, novel fabrication techniques with the ability to control the distribution of the rare-earth ions within the gain medium are urgently needed in order to fabricate REDWAs with high efficiency and low noise. Here, we show that atomic layer deposition (ALD) is an excellent technique to fabricate highly-doped (<1%) RE:Al2O3 gain materials by using its nanoscale engineering ability to delicately control the incorporation of RE ions during the deposition. In our experiment, we fabricated Er:Al2O3 and Tm:Al2O3 thin films with ALD by varying the concentration of RE ions from 1% to 7%. By measuring the photoluminescence response of the fabricated samples, we demonstrate that it is possible to incorporate up to 5% of either Er- or Tm-ions in Al2O3 host before severe quenching occurs. We believe that this technique can be extended to other RE ions as well. Therefore, our results show the exceptionality of ALD as a deposition technique for REDWA technology.

Modulation instability initiated high power all-fiber supercontinuum lasers and their applications

NASA Astrophysics Data System (ADS)

Alexander, Vinay V.; Kulkarni, Ojas P.; Kumar, Malay; Xia, Chenan; Islam, Mohammed N.; Terry, Fred L.; Welsh, Michael J.; Ke, Kevin; Freeman, Michael J.; Neelakandan, Manickam; Chan, Allan

2012-09-01

High average power, all-fiber integrated, broadband supercontinuum (SC) sources are demonstrated. Architecture for SC generation using amplified picosecond/nanosecond laser diode (LD) pulses followed by modulation instability (MI) induced pulse breakup is presented and used to demonstrate SC sources from the mid-IR to the visible wavelengths. In addition to the simplicity in implementation, this architecture allows scaling up of the SC average power by increasing the pulse repetition rate and the corresponding pump power, while keeping the peak power, and, hence, the spectral extent approximately constant. Using this process, we demonstrate >10 W in a mid-IR SC extending from ˜0.8 to 4 μm, >5 W in a near IR SC extending from ˜0.8 to 2.8 μm, and >0.7 W in a visible SC extending from ˜0.45 to 1.2 μm. SC modulation capability is also demonstrated in a mid-IR SC laser with ˜3.9 W in an SC extending from ˜0.8 to 4.3 μm. The entire system and SC output in this case is modulated by a 500 Hz square wave at 50% duty cycle without any external chopping or modulation. We also explore the use of thulium doped fiber amplifier (TDFA) stages for mid-IR SC generation. In addition to the higher pump to signal conversion efficiency demonstrated in TDFAs compared to erbium/ytterbium doped fiber amplifier (EYFA), the shifting of the SC pump from ˜1.5 to ˜2 μm is pursued with an attempt to generate a longer extending SC into the mid-IR. We demonstrate ˜2.5 times higher optical conversion efficiency from pump to SC generation in wavelengths beyond 3.8 μm in the TDFA versus the EYFA based SC systems. The TDFA SC spectrum extends from ˜1.9 to 4.5 μm with ˜2.6 W at 50% modulation with a 250 Hz square wave. A variety of applications in defense, health care and metrology are also demonstrated using the SC laser systems presented in this paper.

Frequency divide-and-conquer approach to producing octave-wide frequency combs and few-cycle pulses in the mid-IR

NASA Astrophysics Data System (ADS)

Vodopyanov, Konstantin

2014-05-01

I will present a new technique for extending frequency combs to the highly desirable yet difficult-to-achieve mid-IR spectral range. The technique is based on subharmonic optical parametric oscillation (OPO) that can be considered as a reverse of the second harmonic generation process. The frequency comb of a pump laser is transposed to half of its central frequency and simultaneously spectrally augmented, thanks to an enormous gain bandwidth of the OPO near degeneracy, as well as due to massive cross-coupling between the laser and the OPO frequency comb components. Using ultrafast erbium (1.56 microns) or thulium (2 microns)-based fiber lasers as a pump and using thin, sub-mm-long, quasi phase-matched lithium niobate or gallium arsenide crystals, we produce frequency combs centered correspondingly at 3.1 or 4 micron subharmonic of the pump frequency. With the properly managed OPO cavity group velocity dispersion, octave-wide frequency combs spanning 2.5 - 6 micron range were achieved. Due to the doubly-resonant operation, the threshold of such a system is low (typically 10 mW) and by several experiments including measuring frequency beats between the OPO comb teeth and a narrow-linewidth CW laser and by interfering the outputs of two identical but distinct OPOs pumped by the same laser, we established that the frequency comb from a subharmonic OPO is phase-locked to that of the pump laser. Pulse duration measurements show that for the optimal intracavity dispersion conditions, we generate sub 5-cycle pulses at the subharmonic of the pump. I will also talk about applications of our mid-IR frequency combs to trace gas detection, where part-per-billion sensitivity of molecular detection is achieved as well as about Fourier spectroscopy using a dual-comb system consisting of two phase-locked lasers. I thank NASA, Office of Naval Research, Air Force Office of Scientific Research, Agilent Technologies, Sanofi- Aventis, Stanford University Bio-X, Stanford Medical School, and Stanford Woods Institute for their financial support.

Compact, highly efficient, single-frequency 25W, 2051nm Tm fiber-based MOPA for CO2 trace-gas laser space transmitter

NASA Astrophysics Data System (ADS)

Engin, Doruk; Chuang, Ti; Litvinovitch, Slava; Storm, Mark

2017-08-01

Fibertek has developed and demonstrated an ideal high-power; low-risk; low-size, weight, and power (SWaP) 2051 nm laser design meeting the lidar requirements for satellite-based global measurement of carbon dioxide (CO2). The laser design provides a path to space for either a coherent lidar approach being developed by NASA Jet Propulsion Laboratory (JPL)1,2 or an Integrated Path Differential Lidar (IPDA) approach developed by Harris Corp using radio frequency (RF) modulation and being flown as part of a NASA Earth Venture Suborbital Mission—NASA's Atmospheric Carbon and Transport - America.3,4 The thulium (Tm) fiber laser amplifies a <500 kHz linewidth distributed feedback (DFB) laser up to 25 W average power in a polarization maintaining (PM) fiber. The design manages and suppresses all deleterious non-linear effects that can cause linewidth broadening or amplified spontaneous emission (ASE) and meets all lidar requirements. We believe the core laser components, architecture, and design margins can support a coherent or IPDA lidar 10-year space mission. With follow-on funding Fibertek can adapt an existing space-based Technology Readiness Level 6 (TRL-6), 20 W erbium fiber laser package for this Tm design and enable a near-term space mission with an electrical-to-optical (e-o) efficiency of <20%. A cladding-pumped PM Tm fiber-based amplifier optimized for high efficiency and high-power operation at 2051 nm is presented. The two-stage amplifier has been demonstrated to achieve 25 W average power and <16 dB polarization extinction ratio (PER) out of a single-mode PM fiber using a <500 kHz linewidth JPL DFB laser5-7 and 43 dB gain. The power amplifier's optical conversion efficiency is 53%. An internal efficiency of 58% is calculated after correcting for passive losses. The two-stage amplifier sustains its highly efficient operation for a temperature range of 5-40°C. The absence of stimulated Brillouin scattering (SBS) for the narrow linewidth amplification shows promise for further power scaling.

Surface temperature measurements from a stator vane doublet in a turbine afterburner flame using a YAG:Tm thermographic phosphor

NASA Astrophysics Data System (ADS)

Eldridge, Jeffrey I.; Allison, Stephen W.; Jenkins, Thomas P.; Gollub, Sarah L.; Hall, Carl A.; Walker, D. Greg

2016-12-01

Phosphor thermometry measurements in turbine engine environments can be difficult because of high background radiation levels. To address this challenge, luminescence lifetime-based phosphor thermometry measurements were obtained using thulium-doped Y3Al5O12 (YAG:Tm) to take advantage of the emission wavelengths at 365 nm (1D2  →  3H6 transition) and at 456 nm (1D2  →  3F4 transition). At these wavelengths, turbine engine radiation background is reduced compared with emission from longer wavelength phosphors. Temperature measurements of YAG:Tm coatings were demonstrated using decay of both the 365 and 456 nm emission bands in a furnace environment up to 1400 °C. To demonstrate that reliable surface temperatures based on short-wavelength YAG:Tm emission could be obtained from the surface of an actual engine component in a high gas velocity, highly radiative environment, measurements were obtained from a YAG:Tm-coated Honeywell stator vane doublet placed in the afterburner flame exhaust stream of the augmenter-equipped General Electric J85 turbojet test engine at the University of Tennessee Space Institute (UTSI). Using a probe designed for engine insertion, spot temperature measurements were obtained by measuring luminescence decay times over a range of steady state throttle settings as well as during an engine throttle acceleration. YAG:Tm phosphor thermometry measurements of the stator vane surface in the afterburner exhaust stream using the decay of the 456 nm emission band were successfully obtained at temperatures up to almost 1300 °C. Phosphor thermometry measurements acquired with the engine probe using the decay of the 365 nm emission band were not successful at usefully high temperatures because the probe design allowed transmission of intense unfiltered silica Raman scattering that produced photomultiplier tube saturation with extended recovery times. Recommendations are made for probe modifications that will enable temperature measurements using the 365 nm emission band decay, which will be beneficial in environments with strong reflections of combustor radiation.

Optical coherence tomography image-guided smart laser knife for surgery.

PubMed

Katta, Nitesh; McElroy, Austin B; Estrada, Arnold D; Milner, Thomas E

2018-03-01

Surgical oncology can benefit from specialized tools that enhance imaging and enable precise cutting and removal of tissue without damage to adjacent structures. The combination of high-resolution, fast optical coherence tomography (OCT) co-aligned with a nanosecond pulsed thulium (Tm) laser offers advantages over conventional surgical laser systems. Tm lasers provide superior beam quality, high volumetric tissue removal rates with minimal residual thermal footprint in tissue, enabling a reduction in unwanted damage to delicate adjacent sub-surface structures such as nerves or micro-vessels. We investigated such a combined Tm/OCT system with co-aligned imaging and cutting beams-a configuration we call a "smart laser knife." A blow-off model that considers absorption coefficients and beam delivery systems was utilized to predict Tm cut depth, tissue removal rate and spatial distribution of residual thermal injury. Experiments were performed to verify the volumetric removal rate predicted by the model as a function of average power. A bench-top, combined Tm/OCT system was constructed using a 15W 1940 nm nanosecond pulsed Tm fiber laser (500 μJ pulse energy, 100 ns pulse duration, 30 kHz repetition rate) for removing tissue and a swept source laser (1310 ± 70 nm, 100 kHz sweep rate) for OCT imaging. Tissue phantoms were used to demonstrate precise surgery with blood vessel avoidance. Depth imaging informed cutting/removal of targeted tissue structures by the Tm laser was performed. Laser cutting was accomplished around and above phantom blood vessels while avoiding damage to vessel walls. A tissue removal rate of 5.5 mm 3 /sec was achieved experimentally, in comparison to the model prediction of approximately 6 mm 3 /sec. We describe a system that combines OCT and laser tissue modification with a Tm laser. Simulation results of the tissue removal rate using a simple model, as a function of average power, are in good agreement with experimental results using tissue phantoms. Lasers Surg. Med. 50:202-212, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Method for halogenating or radiohalogenating a chemical compound

DOEpatents

Kabalka, George W.

2006-05-09

A method for obtaining a halogenated organic compound, whereby an organotrifluoroborate compound is reacted with a halide ion in the presence of an oxidizing agent to produce the corresponding halogenated organic compound. The method may be used for producing radiohalogenated organic compounds.

Ultrabright fluorescent OLEDS using triplet sinks

DOEpatents

Zhang, Yifan; Forrest, Stephen R; Thompson, Mark

2013-06-04

A first device is provided. The first device further comprises an organic light emitting device. The organic light emitting device further comprises an anode, a cathode, and an emissive layer disposed between the anode and the cathode. The emissive layer further comprises an organic host compound, an organic emitting compound capable of fluorescent emission at room temperature, and an organic dopant compound. The triplet energy of the dopant compound is lower than the triplet energy of the host compound. The dopant compound does not strongly absorb the fluorescent emission of the emitting compound.

Investigation on modes of toxic action to rats based on aliphatic and aromatic compounds and comparison with fish toxicity based on exposure routes.

PubMed

He, Jia; Li, Jin J; Wen, Yang; Tai, Hong W; Yu, Yang; Qin, Wei C; Su, Li M; Zhao, Yuan H

2015-06-01

The modes of toxic action (MOAs) play an important role in the assessment of the ecotoxicity of organic pollutants. However, few studies have been reported on the MOAs in rat toxicity. In this paper, the toxic contributions of functional groups in 1255 aromatic compounds were calculated from regression and were then compared with the toxic contributions in aliphatic compounds. The results show that some functional groups have same toxic contributions both in aromatic and aliphatic compounds, but some have not. To investigate the MOAs in rat toxicity, the distribution of toxic ratio (TR) was examined for well-known baseline and less inert compounds and thresholds of log TR=0.3 and 0.5 were used to classify baseline, less inert and reactive compounds. The results showed that some compounds identified as baseline compounds in fish toxicity were also classified as baseline compounds in rat toxicity. Except for phenols and anilines which were identified as less inert compounds in fish toxicity, aromatic compounds with functional groups such as ether, nitrile, nitrophenol, isocyanatoe and chloro were identified as less inert chemicals in rat toxicity. Reactive compounds identified in fish toxicity exhibit greater toxicity to rats. These compounds can undergo nucleophilic substitution, acylation and Schiff base formation with biological macromolecules. The critical body residues (CBRs) calculated from absorption and bioconcentration show that log 1/CBRs in rat toxicity are not equal to that in fish for some compounds. It suggests that the exposure route can affect the identification of MOAs between these two species for these compounds. Copyright © 2015 Elsevier Ltd. All rights reserved.

Potential Compounds for Oral Cancer Treatment: Resveratrol, Nimbolide, Lovastatin, Bortezomib, Vorinostat, Berberine, Pterostilbene, Deguelin, Andrographolide, and Colchicine

PubMed Central

Bundela, Saurabh; Sharma, Anjana; Bisen, Prakash S.

2015-01-01

Oral cancer is one of the main causes of cancer-related deaths in South-Asian countries. There are very limited treatment options available for oral cancer. Research endeavors focused on discovery and development of novel therapies for oral cancer, is necessary to control the ever rising oral cancer related mortalities. We mined the large pool of compounds from the publicly available compound databases, to identify potential therapeutic compounds for oral cancer. Over 84 million compounds were screened for the possible anti-cancer activity by custom build SVM classifier. The molecular targets of the predicted anti-cancer compounds were mined from reliable sources like experimental bioassays studies associated with the compound, and from protein-compound interaction databases. Therapeutic compounds from DrugBank, and a list of natural anti-cancer compounds derived from literature mining of published studies, were used for building partial least squares regression model. The regression model thus built, was used for the estimation of oral cancer specific weights based on the molecular targets. These weights were used to compute scores for screening the predicted anti-cancer compounds for their potential to treat oral cancer. The list of potential compounds was annotated with corresponding physicochemical properties, cancer specific bioactivity evidences, and literature evidences. In all, 288 compounds with the potential to treat oral cancer were identified in the current study. The majority of the compounds in this list are natural products, which are well-tolerated and have minimal side-effects compared to the synthetic counterparts. Some of the potential therapeutic compounds identified in the current study are resveratrol, nimbolide, lovastatin, bortezomib, vorinostat, berberine, pterostilbene, deguelin, andrographolide, and colchicine. PMID:26536350

Drugs as habitable planets in the space of dark chemical matter.

PubMed

Siramshetty, Vishal B; Preissner, Robert

2018-03-01

A recent study demonstrated antifungal activity of dark chemical matter (DCM) compounds that were otherwise inactive in more than 100 HTS assays. These compounds were proposed to possess unique activity and 'clean' safety profiles. Here, we present an outlook of the promiscuity and safety of these compounds by retrospectively comparing their chemical and biological spaces with those of drugs. Significant amounts of marketed drugs (16%), withdrawn drugs (16.5%) and natural compounds (3.5%) share structural identity with DCM. Compound promiscuity assessment indicates that dark matter compounds could potentially interact with multiple biological targets. Further, thousands of DCM compounds showed presence of frequent-hitting pan-assay interference compound (PAINS) substructures. In light of these observations, filtering these compounds from screening libraries can be an irrevocable loss. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Mu.Ta.Lig. Chemotheca: A community-populated molecular database for multi-target ligands identification and compound-repurposing

NASA Astrophysics Data System (ADS)

Ortuso, Francesco; Bagetta, Donatella; Maruca, Annalisa; Talarico, Carmine; Bolognesi, Maria L.; Haider, Norbert; Borges, Fernanda; Bryant, Sharon; Langer, Thierry; Senderowitz, Hanoch; Alcaro, Stefano

2018-04-01

Abstract For every lead compound developed in medicinal chemistry research, numerous other inactive or less active candidates are synthetized/isolated and tested. The majority of these compounds will not be selected for further development due to a sub-optimal pharmacological profile. However, some poorly active or even inactive compounds could live a second life if tested against other targets. Thus, new therapeutic opportunities could emerge and synergistic activities could be identified and exploited for existing compounds by sharing information between researchers who are working on different targets. The Mu.Ta.Lig (Multi-Target Ligand) Chemotheca database aims to offer such opportunities by facilitating information exchange among researchers worldwide. After a preliminary registration, users can (a) virtually upload structures and activity data for their compounds with corresponding, and eventually known activity data, and (b) search for other available compounds uploaded by the users community. Each piece of information about given compounds is owned by the user who initially uploaded it and multiple ownership is possible (occurs if different users uploaded the same compounds or information pertaining to the same compounds). A web-based graphical user interface has been developed to assist compound uploading, compounds searching and data retrieval. Physico-chemical and ADME properties as well as substructure-based PAINS evaluations are computed on the fly for each uploaded compound. Samples of compounds that match a set of search criteria and additional data on these compounds could be requested directly from their owners with no mediation by the Mu.Ta.Lig Chemotheca team. Guest access provides a simplified search interface to retrieve only basic information such as compound IDs and related 2D or 3D chemical structures. Moreover, some compounds can be hidden from Guest users according to an owner’s decision. In contrast, registered users have full access to all of the Chemotheca data including the permission to upload new compounds and/or update experimental/theoretical data (e.g., activities against new targets tested) related to already stored compounds. In order to facilitate scientific collaborations, all available data are connected to the corresponding owner’s email address (available for registered users only). The Chemotheca web site is accessible at http://chemotheca.unicz.it.

The Mu.Ta.Lig. Chemotheca: A Community-Populated Molecular Database for Multi-Target Ligands Identification and Compound-Repurposing.

PubMed

Ortuso, Francesco; Bagetta, Donatella; Maruca, Annalisa; Talarico, Carmine; Bolognesi, Maria L; Haider, Norbert; Borges, Fernanda; Bryant, Sharon; Langer, Thierry; Senderowitz, Hanoch; Alcaro, Stefano

2018-01-01

For every lead compound developed in medicinal chemistry research, numerous other inactive or less active candidates are synthetized/isolated and tested. The majority of these compounds will not be selected for further development due to a sub-optimal pharmacological profile. However, some poorly active or even inactive compounds could live a second life if tested against other targets. Thus, new therapeutic opportunities could emerge and synergistic activities could be identified and exploited for existing compounds by sharing information between researchers who are working on different targets. The Mu.Ta.Lig (Multi-Target Ligand) Chemotheca database aims to offer such opportunities by facilitating information exchange among researchers worldwide. After a preliminary registration, users can (a) virtually upload structures and activity data for their compounds with corresponding, and eventually known activity data, and (b) search for other available compounds uploaded by the users community. Each piece of information about given compounds is owned by the user who initially uploaded it and multiple ownership is possible (this occurs if different users uploaded the same compounds or information pertaining to the same compounds). A web-based graphical user interface has been developed to assist compound uploading, compounds searching and data retrieval. Physico-chemical and ADME properties as well as substructure-based PAINS evaluations are computed on the fly for each uploaded compound. Samples of compounds that match a set of search criteria and additional data on these compounds could be requested directly from their owners with no mediation by the Mu.Ta.Lig Chemotheca team. Guest access provides a simplified search interface to retrieve only basic information such as compound IDs and related 2D or 3D chemical structures. Moreover, some compounds can be hidden to Guest users according to an owner's decision. In contrast, registered users have full access to all of the Chemotheca data including the permission to upload new compounds and/or update experimental/theoretical data (e.g., activities against new targets tested) related to already stored compounds. In order to facilitate scientific collaborations, all available data are connected to the corresponding owner's email address (available for registered users only). The Chemotheca web site is accessible at http://chemotheca.unicz.it.

Discovery of Novel Anti-prion Compounds Using In Silico and In Vitro Approaches

PubMed Central

Hyeon, Jae Wook; Choi, Jiwon; Kim, Su Yeon; Govindaraj, Rajiv Gandhi; Jam Hwang, Kyu; Lee, Yeong Seon; An, Seong Soo A.; Lee, Myung Koo; Joung, Jong Young; No, Kyoung Tai; Lee, Jeongmin

2015-01-01

Prion diseases are associated with the conformational conversion of the physiological form of cellular prion protein (PrPC) to the pathogenic form, PrPSc. Compounds that inhibit this process by blocking conversion to the PrPSc could provide useful anti-prion therapies. However, no suitable drugs have been identified to date. To identify novel anti-prion compounds, we developed a combined structure- and ligand-based virtual screening system in silico. Virtual screening of a 700,000-compound database, followed by cluster analysis, identified 37 compounds with strong interactions with essential hotspot PrP residues identified in a previous study of PrPC interaction with a known anti-prion compound (GN8). These compounds were tested in vitro using a multimer detection system, cell-based assays, and surface plasmon resonance. Some compounds effectively reduced PrPSc levels and one of these compounds also showed a high binding affinity for PrPC. These results provide a promising starting point for the development of anti-prion compounds. PMID:26449325

High-Temperature Syntheses of New, Thermally-Stable Chemical Compounds.

DTIC Science & Technology

SYNTHESIS(CHEMISTRY), HEAT RESISTANT PLASTICS, NITRILES, FLUORINE COMPOUNDS, COMPLEX COMPOUNDS, NITROGEN, SULFIDES, ORGANOMETALLIC COMPOUNDS, ORGANOBORANES, BORIDES, SPINEL, CARBIDES, NITRIDES, SILICIDES .

Response of Bioluminescent Bacteria to Alkyltin Compounds.

DTIC Science & Technology

1987-12-01

found in the butyltiri series of compounds; tributyltin was (’Stimes more toxic than dibutyltin and (- 50 times more toxic than (mono)butyltin. When...correlations between compounds, tributyltin was -35 tine more Kicrotxit and fish bLoessays for pure toxic than dibutyltin end -750 times More compounds and...the compounds as a decrease in toxicity (5) tributyltin compounds ea -150 tines more and a method to study synergistic andtoxic than trinethyltia

Identification and quantification of volatile organic compounds using systematic single-ion chromatograms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsuchiya, Yoshio; Kanabus-Kaminska, J.M.

1996-12-31

In order to determine the background level of volatile organic compounds (VOCs) in Canadian indoor air, a method of identification and quantification at a level of 0.3 {micro}g/m{sup 3} using systematic single-ion chromatograms (SICs) has been developed. The compounds selected for measurement included several halogenated compounds, oxygen compounds, terpenes, and C8 to C16 n-alkanes. Air samples were taken in 3-layered sorbent tubes and trapped compounds were thermally desorbed into the helium stream of a gas chromatograph/mass spectrometer (GC/MS) analytical system. Total quantities of volatile organic compounds (TVOCs) were measured using a flame ionization detector (FID). Individual compounds were analyzed bymore » a GC/MS. For the identification of compounds in the main stream GC effluent, both the specific GC retention and mass spectra were used. About 50 selected SICs were routinely extracted from a total ion chromatogram (TIC) to detect and quantify compounds. For each compound, a single representative ion was selected. The specific retention was calculated from the elution time on the SIC. For quantification, ion counts under a peak in the SIC were measured. The single-ion MS response factor for some of the compounds was experimentally determined using a dynamic reference procedure.« less

Analysis and Identification of Aptamer-Compound Interactions with a Maximum Relevance Minimum Redundancy and Nearest Neighbor Algorithm

PubMed Central

Wang, ShaoPeng; Zhang, Yu-Hang; Lu, Jing; Cui, Weiren; Hu, Jerry; Cai, Yu-Dong

2016-01-01

The development of biochemistry and molecular biology has revealed an increasingly important role of compounds in several biological processes. Like the aptamer-protein interaction, aptamer-compound interaction attracts increasing attention. However, it is time-consuming to select proper aptamers against compounds using traditional methods, such as exponential enrichment. Thus, there is an urgent need to design effective computational methods for searching effective aptamers against compounds. This study attempted to extract important features for aptamer-compound interactions using feature selection methods, such as Maximum Relevance Minimum Redundancy, as well as incremental feature selection. Each aptamer-compound pair was represented by properties derived from the aptamer and compound, including frequencies of single nucleotides and dinucleotides for the aptamer, as well as the constitutional, electrostatic, quantum-chemical, and space conformational descriptors of the compounds. As a result, some important features were obtained. To confirm the importance of the obtained features, we further discussed the associations between them and aptamer-compound interactions. Simultaneously, an optimal prediction model based on the nearest neighbor algorithm was built to identify aptamer-compound interactions, which has the potential to be a useful tool for the identification of novel aptamer-compound interactions. The program is available upon the request. PMID:26955638

Pharmacological Evaluation and Preparation of Nonsteroidal Anti-Inflammatory Drugs Containing an N-Acyl Hydrazone Subunit

PubMed Central

de Melo, Thais Regina Ferreira; Chelucci, Rafael Consolin; Pires, Maria Elisa Lopes; Dutra, Luiz Antonio; Barbieri, Karina Pereira; Bosquesi, Priscila Longhin; Trossini, Gustavo Henrique Goulart; Chung, Man Chin; dos Santos, Jean Leandro

2014-01-01

A series of anti-inflammatory derivatives containing an N-acyl hydrazone subunit (4a–e) were synthesized and characterized. Docking studies were performed that suggest that compounds 4a–e bind to cyclooxygenase (COX)-1 and COX-2 isoforms, but with higher affinity for COX-2. The compounds display similar anti-inflammatory activities in vivo, although compound 4c is the most effective compound for inhibiting rat paw edema, with a reduction in the extent of inflammation of 35.9% and 52.8% at 2 and 4 h, respectively. The anti-inflammatory activity of N-acyl hydrazone derivatives was inferior to their respective parent drugs, except for compound 4c after 5 h. Ulcerogenic studies revealed that compounds 4a–e are less gastrotoxic than the respective parent drug. Compounds 4b–e demonstrated mucosal damage comparable to celecoxib. The in vivo analgesic activities of the compounds are higher than the respective parent drug for compounds 4a–b and 4d–e. Compound 4a was more active than dipyrone in reducing acetic-acid-induced abdominal constrictions. Our results indicate that compounds 4a–e are anti-inflammatory and analgesic compounds with reduced gastrotoxicity compared to their respective parent non-steroidal anti-inflammatory drugs. PMID:24714090

Analysis and Identification of Aptamer-Compound Interactions with a Maximum Relevance Minimum Redundancy and Nearest Neighbor Algorithm.

PubMed

Wang, ShaoPeng; Zhang, Yu-Hang; Lu, Jing; Cui, Weiren; Hu, Jerry; Cai, Yu-Dong

2016-01-01

The development of biochemistry and molecular biology has revealed an increasingly important role of compounds in several biological processes. Like the aptamer-protein interaction, aptamer-compound interaction attracts increasing attention. However, it is time-consuming to select proper aptamers against compounds using traditional methods, such as exponential enrichment. Thus, there is an urgent need to design effective computational methods for searching effective aptamers against compounds. This study attempted to extract important features for aptamer-compound interactions using feature selection methods, such as Maximum Relevance Minimum Redundancy, as well as incremental feature selection. Each aptamer-compound pair was represented by properties derived from the aptamer and compound, including frequencies of single nucleotides and dinucleotides for the aptamer, as well as the constitutional, electrostatic, quantum-chemical, and space conformational descriptors of the compounds. As a result, some important features were obtained. To confirm the importance of the obtained features, we further discussed the associations between them and aptamer-compound interactions. Simultaneously, an optimal prediction model based on the nearest neighbor algorithm was built to identify aptamer-compound interactions, which has the potential to be a useful tool for the identification of novel aptamer-compound interactions. The program is available upon the request.

Monomers, polymers and articles containing the same from sugar derived compounds

DOEpatents

Gallagher, James; Reineke, Theresa; Hillmyer, Marc A.

2016-11-29

Disclosed herein are monomers formed by reacting a sugar derived compound(s) comprising a lactone and two hydroxyls with a compound(s) comprising an isocyanate and an acrylate or methacrylate. Polymers formed from such monomers, and articles formed from the polymers are also disclosed.

MANUFACTURING METHODS FOR PHASE SHIFTERS.

DTIC Science & Technology

MANUFACTURING), (*PHASE SHIFT CIRCUITS, FERRITES, GARNET , DIGITAL SYSTEMS, X BAND, C BAND, S BAND, RADAR EQUIPMENT, MAGNETIC MATERIALS, YTTRIUM COMPOUNDS, GADOLINIUM COMPOUNDS, ALUMINUM COMPOUNDS, IRON COMPOUNDS, OXIDES.

Compound Nouns and Category Structure in Young Children.

ERIC Educational Resources Information Center

Clark, Eve V.; And Others

1985-01-01

In two experiments 96 children and eight adults were tested for comprehension of the modifier-head relation in compounds such as apple-knife or were asked to label objects with compounds. Results show that by age three children reliably interpret novel compounds and made use of novel compounds to subcategorize. (RH)

Compounding in Ukraine.

PubMed

Zdoryk, Oleksandr A; Georgiyants, Victoriya A; Gryzodub, Oleksandr I; Schnatz, Rick

2013-01-01

Pharmaceutical compounding in modern Ukraine has a rich history and goes back to ancient times. Today in the Ukraine, there is a revival of compounding practice, the opening of private compounding pharmacies, updating of legislative framework and requirements of the State Pharmacopeia of Ukraine for compounding preparations, and the introduction of Good Pharmaceutical Practice.

Analytic Methods Used in Quality Control in a Compounding Pharmacy.

PubMed

Allen, Loyd V

2017-01-01

Analytical testing will no doubt become a more important part of pharmaceutical compounding as the public and regulatory agencies demand increasing documentation of the quality of compounded preparations. Compounding pharmacists must decide what types of testing and what amount of testing to include in their quality-control programs, and whether testing should be done in-house or outsourced. Like pharmaceutical compounding, analytical testing should be performed only by those who are appropriately trained and qualified. This article discusses the analytical methods that are used in quality control in a compounding pharmacy. Copyright© by International Journal of Pharmaceutical Compounding, Inc.

Fig volatile compounds--a first comparative study.

PubMed

Grison-Pigé, Laure; Hossaert-McKey, Martine; Greeff, Jaco M; Bessière, Jean-Marie

2002-09-01

We analysed the compounds of volatile blends released by receptive figs of twenty Ficus species to attract their specific pollinating wasps. In all, 99 different compounds were identified. The compounds are mainly terpenoids, aliphatic compounds and products from the shikimic acid pathway. In each species blend, there are few major compounds, which are generally common among floral fragrances. Most species blends also include rare compounds, but generally their proportion in the blend is low. A possible basis for species-specificity of Ficus-wasp interactions is discussed in relation to the patterns of volatiles found in this interspecies comparison. Copyright 2002 Elsevier Science Ltd.

Phytochemical Investigations of Three Rhodocodon (Hyacinthaceae Sensu APG II) Species.

PubMed

Schwikkard, Sianne; Alqahtani, Alaa; Knirsch, Walter; Wetschnig, Wolfgang; Jaksevicius, Andrius; Opara, Elizabeth I; Langat, Moses K; Andriantiana, Jackie L; Mulholland, Dulcie A

2017-01-27

The genus Rhodocodon (Hyacinthaceae sensu APG II) is endemic to Madagascar, and its phytochemistry has not been described previously. The phytochemistry of three species in this genus has been investigated, and eight compounds, including three bufadienolides (compounds 1, 4, and 5), a norlignan (2), and four homoisoflavonoids (compounds 3 and 6-8), have been isolated and identified. Compounds 1-3 and 6-8 have not been described previously. The COX-2 inhibitory activity of compound 6 and compound 7 acetate (compound 7A) was investigated on isolated colorectal cancer cells. Compounds 6 and 7A inhibited COX-2 by 10% and 8%, respectively, at a concentration of 12.5 μM compared to 12% for 1 mM aspirin (the positive control).

Chemical vapor deposition of group IIIB metals

DOEpatents

Erbil, A.

1989-11-21

Coatings of Group IIIB metals and compounds thereof are formed by chemical vapor deposition, in which a heat decomposable organometallic compound of the formula given in the patent where M is a Group IIIB metal, such as lanthanum or yttrium and R is a lower alkyl or alkenyl radical containing from 2 to about 6 carbon atoms, with a heated substrate which is above the decomposition temperature of the organometallic compound. The pure metal is obtained when the compound of the formula 1 is the sole heat decomposable compound present and deposition is carried out under nonoxidizing conditions. Intermetallic compounds such as lanthanum telluride can be deposited from a lanthanum compound of formula 1 and a heat decomposable tellurium compound under nonoxidizing conditions.

Chemical vapor deposition of group IIIB metals

DOEpatents

Erbil, Ahmet

1989-01-01

Coatings of Group IIIB metals and compounds thereof are formed by chemical vapor deposition, in which a heat decomposable organometallic compound of the formula (I) ##STR1## where M is a Group IIIB metal, such as lanthanum or yttrium and R is a lower alkyl or alkenyl radical containing from 2 to about 6 carbon atoms, with a heated substrate which is above the decomposition temperature of the organometallic compound. The pure metal is obtained when the compound of the formula I is the sole heat decomposable compound present and deposition is carried out under nonoxidizing conditions. Intermetallic compounds such as lanthanum telluride can be deposited from a lanthanum compound of formula I and a heat decomposable tellurium compound under nonoxidizing conditions.

Biotransformation of natural gas and oil compounds associated with marine oil discharges.

PubMed

Brakstad, Odd Gunnar; Almås, Inger K; Krause, Daniel Franklin

2017-09-01

Field data from the Deepwater Horizon (DWH) oil spill in the Gulf of Mexico (GoM) suggested that oxidation of gas compounds stimulated biodegradation of oil compounds in the deep sea plume. We performed experiments with local seawater from a Norwegian fjord to examine if the presence of dissolved gas compounds (methane, ethane and propane) affected biodegradation of volatile oil compounds, and if oil compounds likewise affected gas compound oxidation. The results from the experiment showed comparable oil compound biotransformation rates in seawater at 5 °C between seawater with and without soluble gases. Gas oxidation was not affected by the presence of volatile oil compounds. Contrary to DWH deep sea plume data, propane oxidation was not faster than methane oxidation. These data may reflect variations between biodegradation of oil and gas in seawater environments with different history of oil and gas exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Bilingual reading of compound words.

PubMed

Ko, In Yeong; Wang, Min; Kim, Say Young

2011-02-01

The present study investigated whether bilingual readers activate constituents of compound words in one language while processing compound words in the other language via decomposition. Two experiments using a lexical decision task were conducted with adult Korean-English bilingual readers. In Experiment 1, the lexical decision of real English compound words was more accurate when the translated compounds (the combination of the translation equivalents of the constituents) in Korean (the nontarget language) were real words than when they were nonwords. In Experiment 2, when the frequency of the second constituents of compound words in English (the target language) was manipulated, the effect of lexical status of the translated compounds was greater on the compounds with high-frequency second constituents than on those with low-frequency second constituents in the target language. Together, these results provided evidence for morphological decomposition and cross-language activation in bilingual reading of compound words.

Pharmaceutical compounding or pharmaceutical manufacturing? A regulatory perspective.

PubMed

Timko, Robert J; Crooker, Philip E M

2014-01-01

At one time, nearly all prescriptions were compounded preparations. There is an ongoing demand for compounded prescription medications because manufacturers cannot fulfill the needs of all individual patients. Compounding pharmacies are a long standing yet less frequently discussed element in the complex matrix of prescription drug manufacturing, distribution, and patient use. The drug shortage situation for many necessary and life-saving drug products is a complicating factor that has led to the numerous quality issues that currently plague large-scale compounding pharmacies. The states are the primary regulator of pharmacies, including community drug stores, large chains, and specialty pharmacies. Pharmacies making and distributing drugs in a way that is outside the bounds of traditional pharmacy compounding are of great concern to the U.S. Food and Drug Administration. The U.S. Congress has recently passed the Drug Quality and Security Act. This legislation establishes a clear boundary between traditional compounders and compounding manufacturers. It clarifies a national, uniform set of rules for compounding manufacturers while preserving the states' primary role in traditional pharmacy regulation. It clarifies the U.S. Food and Drug Administration's authority over the compounding of human drugs while requiring the Agency to engage and coordinate with states to ensure the safety of compounded drugs.

Crystallographic site swapping of La3+ ion in BaA'LaTeO6 (A' = Na, K, Rb) double perovskite type compounds: diffraction and photoluminescence evidence for the site swapping.

PubMed

Phatak, R; Gupta, S K; Krishnan, K; Sali, S K; Godbole, S V; Das, A

2014-02-28

Double perovskite type compounds of the formula BaA'LaTeO6 (A' = Na, K, Rb) were synthesized by solid state route and their crystal structures were determined by Rietveld analysis using powder X-ray diffraction and neutron diffraction data. Na compound crystallizes in the monoclinic system with P2₁/n space group whereas, K and Rb compounds crystallize in Fm3m space group. All the three compounds show rock salt type ordering at B site. Crystal structure analysis shows that La ion occupies A site in Na compound whereas, it occupies B site in K and Rb compounds according to the general formula of AA'BB'O6 for a double perovskite type compound. Effect of this crystallographic site swapping of the La ion was also observed in the photoluminescence study by doping Eu(3+) in La(3+) site. The large decrease in the intensity of the electric dipole ((5)D0-(7)F2) transition in the Rb compound compared to the Na compound indicates that Eu(3+) ion resides in the centrosymmetric octahedral environment in the Rb compound.

Estimating the densities of benzene-derived explosives using atomic volumes.

PubMed

Ghule, Vikas D; Nirwan, Ayushi; Devi, Alka

2018-02-09

The application of average atomic volumes to predict the crystal densities of benzene-derived energetic compounds of general formula C a H b N c O d is presented, along with the reliability of this method. The densities of 119 neutral nitrobenzenes, energetic salts, and cocrystals with diverse compositions were estimated and compared with experimental data. Of the 74 nitrobenzenes for which direct comparisons could be made, the % error in the estimated density was within 0-3% for 54 compounds, 3-5% for 12 compounds, and 5-8% for the remaining 8 compounds. Among 45 energetic salts and cocrystals, the % error in the estimated density was within 0-3% for 25 compounds, 3-5% for 13 compounds, and 5-7.4% for 7 compounds. The absolute error surpassed 0.05 g/cm 3 for 27 of the 119 compounds (22%). The largest errors occurred for compounds containing fused rings and for compounds with three -NH 2 or -OH groups. Overall, the present approach for estimating the densities of benzene-derived explosives with different functional groups was found to be reliable. Graphical abstract Application and reliability of average atom volume in the crystal density prediction of energetic compounds containing benzene ring.

Pre-compound emission in low-energy heavy-ion interactions

NASA Astrophysics Data System (ADS)

Sharma, Manoj Kumar; Shuaib, Mohd.; Sharma, Vijay R.; Yadav, Abhishek; Singh, Pushpendra P.; Singh, Devendra P.; Unnati; Singh, B. P.; Prasad, R.

2017-11-01

Recent experimental studies have shown the presence of pre-compound emission component in heavy ion reactions at low projectile energy ranging from 4 to 7 MeV/nucleons. In earlier measurements strength of the pre-compound component has been estimated from the difference in forward-backward distributions of emitted particles. Present measurement is a part of an ongoing program on the study of reaction dynamics of heavy ion interactions at low energies aimed at investigating the effect of momentum transfer in compound, precompound, complete and incomplete fusion processes in heavy ion reactions. In the present work on the basis of momentum transfer the measurement of the recoil range distributions of heavy residues has been used to decipher the components of compound and pre-compound emission processes in the fusion of 16O projectile with 159Tb and 169Tm targets. The analysis of recoil range distribution measurements show two distinct linear momentum transfer components corresponding to pre-compound and compound nucleus processes are involved. In order to obtain the mean input angular momentum associated with compound and pre-compound emission processes, an online measurement of the spin distributions of the residues has been performed. The analysis of spin distribution indicate that the mean input angular momentum associated with pre-compound products is found to be relatively lower than that associated with compound nucleus process. The pre-compound components obtained from the present analysis are consistent with those obtained from the analysis of excitation functions.

[Determination of flavor compounds in foxtail millet wine by gas chromatography-mass spectrometry coupled with headspace solid phase microextraction].

PubMed

Liu, Jingke; Zhang, Aixia; Li, Shaohui; Zhao, Wei; Zhang, Yuzong; Xing, Guosheng

2017-11-08

To comprehensively understand flavor compounds and aroma characteristics of foxtail millet wine, extraction conditions were optimized with 85 μm polyacrylate (PA), 100 μm polydimethylsiloxane (PDMS), 75 μm carboxen (CAR)/PDMS and 50/30 μm divinylbenzene (DVB)/CAR/PDMS fibers. The flavor compounds in foxtail millet wine were investigated by gas chromatography-mass spectrometry (GC-MS) coupled with headspace solid phase microextraction (HS-SPME), and the odor characteristics and intensity were analyzed by odor active values (OAVs). The samples of 8 mL were placed in headspace vials with 1.5 g NaCl, then the headspace vials were heated at 60℃ for 40 min. Using HS-SPME with different fibers, a total of 55 flavor compounds were identified from the samples, including alcohols, esters, benzene derivatives, hydrocarbons, acids, aldehydes, ketones, terpenes, phenols and heterocycle compounds. The main flavor compounds were alcohols compounds. According to their OAVs, phenylethyl alcohol, styrene, 1-methyl-naphthalene, 2-methyl-naphthalene, benzaldehyde, benzeneacetaldehyde and 2-methoxy-phenol were established to be odor-active compounds. Phenylethyl alcohol and benzeneacetaldehyde were the most prominent odor-active compounds. PA and PDMS fibers had good extraction effect for polar and nonpolar compounds, respectively. CAR/PDMS and DVB/CAR/PDMS provided a similar compounds profile for moderate polar compounds. This research comprehensively determined flavor compounds of foxtail millet wine, and provided theoretical basis for product development and quality control.

Automated compound classification using a chemical ontology.

PubMed

Bobach, Claudia; Böhme, Timo; Laube, Ulf; Püschel, Anett; Weber, Lutz

2012-12-29

Classification of chemical compounds into compound classes by using structure derived descriptors is a well-established method to aid the evaluation and abstraction of compound properties in chemical compound databases. MeSH and recently ChEBI are examples of chemical ontologies that provide a hierarchical classification of compounds into general compound classes of biological interest based on their structural as well as property or use features. In these ontologies, compounds have been assigned manually to their respective classes. However, with the ever increasing possibilities to extract new compounds from text documents using name-to-structure tools and considering the large number of compounds deposited in databases, automated and comprehensive chemical classification methods are needed to avoid the error prone and time consuming manual classification of compounds. In the present work we implement principles and methods to construct a chemical ontology of classes that shall support the automated, high-quality compound classification in chemical databases or text documents. While SMARTS expressions have already been used to define chemical structure class concepts, in the present work we have extended the expressive power of such class definitions by expanding their structure-based reasoning logic. Thus, to achieve the required precision and granularity of chemical class definitions, sets of SMARTS class definitions are connected by OR and NOT logical operators. In addition, AND logic has been implemented to allow the concomitant use of flexible atom lists and stereochemistry definitions. The resulting chemical ontology is a multi-hierarchical taxonomy of concept nodes connected by directed, transitive relationships. A proposal for a rule based definition of chemical classes has been made that allows to define chemical compound classes more precisely than before. The proposed structure-based reasoning logic allows to translate chemistry expert knowledge into a computer interpretable form, preventing erroneous compound assignments and allowing automatic compound classification. The automated assignment of compounds in databases, compound structure files or text documents to their related ontology classes is possible through the integration with a chemical structure search engine. As an application example, the annotation of chemical structure files with a prototypic ontology is demonstrated.

Automated compound classification using a chemical ontology

PubMed Central

2012-01-01

Background Classification of chemical compounds into compound classes by using structure derived descriptors is a well-established method to aid the evaluation and abstraction of compound properties in chemical compound databases. MeSH and recently ChEBI are examples of chemical ontologies that provide a hierarchical classification of compounds into general compound classes of biological interest based on their structural as well as property or use features. In these ontologies, compounds have been assigned manually to their respective classes. However, with the ever increasing possibilities to extract new compounds from text documents using name-to-structure tools and considering the large number of compounds deposited in databases, automated and comprehensive chemical classification methods are needed to avoid the error prone and time consuming manual classification of compounds. Results In the present work we implement principles and methods to construct a chemical ontology of classes that shall support the automated, high-quality compound classification in chemical databases or text documents. While SMARTS expressions have already been used to define chemical structure class concepts, in the present work we have extended the expressive power of such class definitions by expanding their structure-based reasoning logic. Thus, to achieve the required precision and granularity of chemical class definitions, sets of SMARTS class definitions are connected by OR and NOT logical operators. In addition, AND logic has been implemented to allow the concomitant use of flexible atom lists and stereochemistry definitions. The resulting chemical ontology is a multi-hierarchical taxonomy of concept nodes connected by directed, transitive relationships. Conclusions A proposal for a rule based definition of chemical classes has been made that allows to define chemical compound classes more precisely than before. The proposed structure-based reasoning logic allows to translate chemistry expert knowledge into a computer interpretable form, preventing erroneous compound assignments and allowing automatic compound classification. The automated assignment of compounds in databases, compound structure files or text documents to their related ontology classes is possible through the integration with a chemical structure search engine. As an application example, the annotation of chemical structure files with a prototypic ontology is demonstrated. PMID:23273256

Gasoline-Related Compounds in Lakes Mead and Mohave, Nevada, 2004-06

USGS Publications Warehouse

Lico, Michael S.; Johnson, B. Thomas

2007-01-01

The distribution of man-made organic compounds, specifically gasoline-derived compounds, was investigated from 2004 to 2006 in Lakes Mead and Mohave and one of its tributary streams, Las Vegas Wash. Compounds contained in raw gasoline (benzene, toluene, ethylbenzene, xylenes; also known as BTEX compounds) and those produced during combustion of gasoline (polycyclic aromatic hydrocarbon compounds; also known as PAH compounds) were detected at every site sampled in Lakes Mead and Mohave. Water-quality analyses of samples collected during 2004-06 indicate that motorized watercraft are the major source of these organic compounds to the lakes. Concentrations of BTEX increase as the boating season progresses and decrease to less than detectable levels during the winter when few boats are on the water. Volatilization and microbial degradation most likely are the primary removal mechanisms for BTEX compounds in the lakes. Concentrations of BTEX compounds were highest at sampling points near marinas or popular launching areas. Methyl tert-butyl ether (MTBE) was detected during 2004 but concentrations decreased to less than the detection level during the latter part of the study; most likely due to the removal of MTBE from gasoline purchased in California. Distribution of PAH compounds was similar to that of BTEX compounds, in that, concentrations were highest at popular boating areas and lowest in areas where fewer boats traveled. PAH concentrations were highest at Katherine Landing and North Telephone Cove in Lake Mohave where many personal watercraft with carbureted two-stroke engines ply the waters. Lake-bottom sediment is not a sink for PAH as indicated by the low concentrations detected in sediment samples from both lakes. PAH compounds most likely are removed from the lakes by photochemical degradation. PAH compounds in Las Vegas Wash, which drains the greater Las Vegas metropolitan area, were present in relatively high concentrations in sediment from the upstream reaches. Concentrations of PAH compounds were low in water and sediment samples collected farther downstream, thus the bottom sediment in the upstream part of the wash may be an effective trap for these compounds. Bioavailable PAH compounds were present in all samples as determined using the Fluoroscan method. Microtox acute toxicity profiles indicated that Callville Bay in Lake Mead and the two Lake Mohave sites had only minor evidence that toxic compounds are present.

A strategy to find novel candidate anti-Alzheimer's disease drugs by constructing interaction networks between drug targets and natural compounds in medical plants.

PubMed

Chen, Bi-Wen; Li, Wen-Xing; Wang, Guang-Hui; Li, Gong-Hua; Liu, Jia-Qian; Zheng, Jun-Juan; Wang, Qian; Li, Hui-Juan; Dai, Shao-Xing; Huang, Jing-Fei

2018-01-01

Alzheimer' disease (AD) is an ultimately fatal degenerative brain disorder that has an increasingly large burden on health and social care systems. There are only five drugs for AD on the market, and no new effective medicines have been discovered for many years. Chinese medicinal plants have been used to treat diseases for thousands of years, and screening herbal remedies is a way to develop new drugs. We used molecular docking to screen 30,438 compounds from Traditional Chinese Medicine (TCM) against a comprehensive list of AD target proteins. TCM compounds in the top 0.5% of binding affinity scores for each target protein were selected as our research objects. Structural similarities between existing drugs from DrugBank database and selected TCM compounds as well as the druggability of our candidate compounds were studied. Finally, we searched the CNKI database to obtain studies on anti-AD Chinese plants from 2007 to 2017, and only clinical studies were included. A total of 1,476 compounds (top 0.5%) were selected as drug candidates. Most of these compounds are abundantly found in plants used for treating AD in China, especially the plants from two genera Panax and Morus. We classified the compounds by single target and multiple targets and analyzed the interactions between target proteins and compounds. Analysis of structural similarity revealed that 17 candidate anti-AD compounds were structurally identical to 14 existing approved drugs. Most of them have been reported to have a positive effect in AD. After filtering for compound druggability, we identified 11 anti-AD compounds with favorable properties, seven of which are found in anti-AD Chinese plants. Of 11 anti-AD compounds, four compounds 5,862, 5,863, 5,868, 5,869 have anti-inflammatory activity. The compound 28,814 mainly has immunoregulatory activity. The other six compounds have not yet been reported for any biology activity at present. Natural compounds from TCM provide a broad prospect for the screening of anti-AD drugs. In this work, we established networks to systematically study the connections among natural compounds, approved drugs, TCM plants and AD target proteins with the goal of identifying promising drug candidates. We hope that our study will facilitate in-depth research for the treatment of AD in Chinese medicine.

Identification of compound-protein interactions through the analysis of gene ontology, KEGG enrichment for proteins and molecular fragments of compounds.

PubMed

Chen, Lei; Zhang, Yu-Hang; Zheng, Mingyue; Huang, Tao; Cai, Yu-Dong

2016-12-01

Compound-protein interactions play important roles in every cell via the recognition and regulation of specific functional proteins. The correct identification of compound-protein interactions can lead to a good comprehension of this complicated system and provide useful input for the investigation of various attributes of compounds and proteins. In this study, we attempted to understand this system by extracting properties from both proteins and compounds, in which proteins were represented by gene ontology and KEGG pathway enrichment scores and compounds were represented by molecular fragments. Advanced feature selection methods, including minimum redundancy maximum relevance, incremental feature selection, and the basic machine learning algorithm random forest, were used to analyze these properties and extract core factors for the determination of actual compound-protein interactions. Compound-protein interactions reported in The Binding Databases were used as positive samples. To improve the reliability of the results, the analytic procedure was executed five times using different negative samples. Simultaneously, five optimal prediction methods based on a random forest and yielding maximum MCCs of approximately 77.55 % were constructed and may be useful tools for the prediction of compound-protein interactions. This work provides new clues to understanding the system of compound-protein interactions by analyzing extracted core features. Our results indicate that compound-protein interactions are related to biological processes involving immune, developmental and hormone-associated pathways.

Potential of the octanol-water partition coefficient (logP) to predict the dermal penetration behaviour of amphiphilic compounds in aqueous solutions.

PubMed

Korinth, Gintautas; Wellner, Tanja; Schaller, Karl Heinz; Drexler, Hans

2012-11-23

Aqueous amphiphilic compounds may exhibit enhanced skin penetration compared with neat compounds. Conventional models do not predict this percutaneous penetration behaviour. We investigated the potential of the octanol-water partition coefficient (logP) to predict dermal fluxes for eight compounds applied neat and as 50% aqueous solutions in diffusion cell experiments using human skin. Data for seven other compounds were accessed from literature. In total, seven glycol ethers, three alcohols, two glycols, and three other chemicals were considered. Of these 15 compounds, 10 penetrated faster through the skin as aqueous solutions than as neat compounds. The other five compounds exhibited larger fluxes as neat applications. For 13 of the 15 compounds, a consistent relationship was identified between the percutaneous penetration behaviour and the logP. Compared with the neat applications, positive logP were associated with larger fluxes for eight of the diluted compounds, and negative logP were associated with smaller fluxes for five of the diluted compounds. Our study demonstrates that decreases or enhancements in dermal penetration upon aqueous dilution can be predicted for many compounds from the sign of logP (i.e., positive or negative). This approach may be suitable as a first approximation in risk assessments of dermal exposure. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Large Constituent Families Help Children Parse Compounds

ERIC Educational Resources Information Center

Krott, Andrea; Nicoladis, Elena

2005-01-01

The family size of the constituents of compound words, or the number of compounds sharing the constituents, has been shown to affect adults' access to compound words in the mental lexicon. The present study was designed to see if family size would affect children's segmentation of compounds. Twenty-five English-speaking children between 3;7 and…

Boron-containing amino carboxylic acid compounds and uses thereof

DOEpatents

Kabalka, George W.; Srivastava, Rajiv R.

2000-03-14

Novel compounds which are useful for boron neutron capture therapy (BNCT) are disclosed. The compounds comprise a stable boron-containing group and an aminocycloalkane carboxylic acid group or a boronated acyclic hydrocarbon-linked amino carboxylic acid. Methods for synthesis of the compounds and for use of the compounds in BNCT are disclosed.

Process for preparing a chemical compound enriched in isotope content

DOEpatents

Michaels, Edward D.

1982-01-01

A process to prepare a chemical enriched in isotope content which includes: (a) A chemical exchange reaction between a first and second compound which yields an isotopically enriched first compound and an isotopically depleted second compound; (b) the removal of a portion of the first compound as product and the removal of a portion of the second compound as spent material; (c) the conversion of the remainder of the first compound to the second compound for reflux at the product end of the chemical exchange reaction region; (d) the conversion of the remainder of the second compound to the first compound for reflux at the spent material end of the chemical exchange region; and the cycling of the additional chemicals produced by one conversion reaction to the other conversion reaction, for consumption therein. One of the conversion reactions is an oxidation reaction, and the energy that it yields is used to drive the other conversion reaction, a reduction. The reduction reaction is carried out in a solid polymer electrolyte electrolytic reactor. The overall process is energy efficient and yields no waste by-products.

Soil Organic Chemistry.

ERIC Educational Resources Information Center

Anderson, G.

1979-01-01

A brief review is presented of some of the organic compounds and reactions that occur in soil. Included are nitrogenous compounds, compounds of phosphorus and sulfur, carbohydrates, phenolic compounds, and aliphatic acids. (BB)

Rare Earth Laser Engineering Program. Part II.

DTIC Science & Technology

YTTRIUM ALUMINUM GARNET , NEAR INFRARED RADIATION, CONCENTRATION(CHEMISTRY), YTTRIUM COMPOUNDS, ALUMINUM COMPOUNDS, OXIDES, RELAXATION, RATES...VANADATES, DOPING, LANTHANUM, ERBIUM, HOLMIUM, GADOLINIUM COMPOUNDS, GARNET , TRANSPORT PROPERTIES, OSCILLATORS, LANTHANUM COMPOUNDS, FLUORIDES.

Characterization of the key aroma compounds in pork soup stock by using an aroma extract dilution analysis.

PubMed

Takakura, Yukiko; Osanai, Hiroki; Masuzawa, Takuya; Wakabayashi, Hidehiko; Nishimura, Toshihide

2014-01-01

The aroma extract dilution analysis of an extract prepared from pork stock and subsequent experiments led to the identification of 15 aroma-active compounds in the flavor dilution factor range of 64-2048. Omission experiments to select the most aroma-active compounds from the 15 odor compounds suggested acetol, octanoic acid, δ-decalactone, and decanoic acid as the main active compounds contributing to the aroma of pork stock. Aroma recombination, addition, and omission experiments of these four aroma compounds in taste-reconstituted pork stock showed that each compound had an individual aroma profile. A comparison of the overall aroma between this recombined mixture and pork stock showed strong similarity, suggesting that the key aroma compounds had been successfully identified.

Design and simulation of a superposition compound eye system based on hybrid diffractive-refractive lenses.

PubMed

Zhang, Shuqing; Zhou, Luyang; Xue, Changxi; Wang, Lei

2017-09-10

Compound eyes offer a promising field of miniaturized imaging systems. In one application of a compound eye, superposition of compound eye systems forms a composite image by superposing the images produced by different channels. The geometric configuration of superposition compound eye systems is achieved by three micro-lens arrays with different pitches and focal lengths. High resolution is indispensable for the practicability of superposition compound eye systems. In this paper, hybrid diffractive-refractive lenses are introduced into the design of a compound eye system for this purpose. With the help of ZEMAX, two superposition compound eye systems with and without hybrid diffractive-refractive lenses were separately designed. Then, we demonstrate the effectiveness of using a hybrid diffractive-refractive lens to improve the image quality.

Phytochemical Investigations on Chemical Constituents of Achillea tenuifolia Lam

PubMed Central

Moradkhani, Shirin; Kobarfard, Farzad; Ayatollahi, Seyed Abdol Majid

2014-01-01

Achillea tenuifolia Lam. (Asteraceae) afforded a methanolic extract from which after fractionation in solvents with different polarities, two known flavones 3’, 5- dihydroxy- 4’, 6, 7- trimethoxy flavone (eupatorine, compound 3), 5- hydroxy- 3’,4’, 6, 7- tetramethoxyflavone (compound 4), besides stearic acid (compound 1), lupeol (compound 2), daucosterol (β- sitosterol 3-O- β- D- glucopyranoside, compound 5), 2, 4- dihydroxy methyl benzoate (compound 6) were isolated for the first time. The structure of isolated compounds was elucidated by means of different spectroscopic methods such as UV, IR, Mass and 1H- NMR (1D and 2D) and 13C-NMR. For further confirming the structures of isolated compounds, comparison of the spectral data of them with those reported in the litratures have been done. PMID:25276207

Synthesis, Antiinflammatory and Antimicrobial Activity of Some New 1-(3-Phenyl-3,4-Dihydro-2H-1,3-Benzoxazin-6-yl)-Ethanone Derivatives.

PubMed

Akhter, Mymoona; Husain, A; Akhter, N; Khan, M S Y

2011-01-01

Synthesis of title compounds (4a-j) was carried out by following aminomethylation Mannich reaction. Test compounds were effective in inhibiting edema induced by carrageenan. The percent inhibition obseved was in the range of 25-83.3%. Compound (4c, e, h and j) were also tested for analgesic effect and showed percent protection ranging between 57-65%. All the synthesized compounds were active against E. coli and S. aureus but only compounds (4 b, c, e, i and j) were active against B. subtilis. All these compound were also found active against A. niger. Compound 4j was the most active compound with 83.3% inhibition of edema, 65.35% percent protection and inhibited all the three bacterial strains.

Characterization and origin of the 'B' and 'C' compounds in the acid/neutral forensic signatures of heroin - products from the acylation of porphyroxine and subsequent hydrolysis.

PubMed

Casale, John F; Casale, Ellen S; Toske, Steven G; Hays, Patrick A; Panicker, Sini

2017-03-01

Two significant compounds often found in the gas chromatographic analysis of the acid/neutral extracts from illicit heroin have remained uncharacterized for 30 years. The unknown compounds are referred to as the 'B' and 'C' compounds. It has been postulated that these compounds arise from acetylation of porphyroxine, a rhoeadine alkaloid found at trace levels in the opium poppy, Papaver somniferum. Porphyroxine was isolated from opium and acetylated to produce N,O 8 -diacetylporphyroxine. Mild hydrolysis produced N,O 8 -diacetyl-O 14 -desmethyl-epi-porphyroxine (the C compound) and N-acetyl-O 14 -desmethyl-epi-porphyroxine (the B compound). Both N,O 8 -diacetyl-O 14 -desmethyl-epi-porphyroxine and N-acetyl-O 14 -desmethyl-epi-porphyroxine were determined to be C-14 epimers of porphyroxine and N,O 8 -diacetylporphyroxine. The non-epimerized isomers of the B and C compounds were also detected in illicit heroin, but at much lower levels. Chromatographic and spectroscopic data are presented for the aforementioned compounds. The presence/absence and relative concentrations of these compounds is presented for the four types of heroin (Southwest Asian, South American, Southeast Asian, and Mexican). The prevalence of detection for the B and C compounds are Southwest Asian = 92-93%, South American = 64-72%, Southeast Asian = 45-49%, and Mexican ≤ 3%. When detected, the overall trend of relative concentrations of dicaetylporhyroxine, the B-compound, and C-compound is Southwest Asian > South American > Southeast Asian, each by an order of magnitude. These compounds were rarely detected in Mexican heroin. The presence/absence and relative concentrations of these compounds provide pertinent forensic signature characteristics that significantly enhance the final regional classifications. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Inhibitory Effect of Furanic and Phenolic Compounds on Exoelectrogenesis in a Microbial Electrolysis Cell Bioanode

DOE PAGES

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

2016-09-09

Furanic and phenolic compounds are 20 lignocellulose-derived compounds known to inhibit to H2- and ethanol- producing microorganisms in dark fermentation. Bioelectrochemical conversion of furanic and phenolic compounds to electricity or H2 has recently been demonstrated as a productive method to use these compounds. However, potential inhibitory effect of furanic and phenolic compounds on exoelectrogenesis in bioelectrochemical systems is not well understood. This study systematically investigated the inhibitory effect of furfural (FF), 5-hydroxymethylfurfural (HMF), syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) on exoelectrogenesis in the bioanode of a microbial electrolysis cell. A mixture of these five compounds atmore » an increasing initial total concentration from 0.8 to 8.0 g/L resulted in current decrease up to 91%. The observed inhibition primarily affected exoelectrogenesis, instead of non-exoelectrogenic biotransformation pathways (e.g., fermentation) of the five compounds. Furthermore, the parent compounds at a high concentration, as opposed to their biotransformation products, were responsible for the observed inhibition. Tests with individual compounds show that all five parent compounds contributed to the observed inhibition by the mixture. The IC50 (concentration resulting in 50% current decrease) was estimated as 2.7 g/L for FF, 3.0 g/L for HMF, 1.9 g/L for SA, 2.1 g/L for VA and 2.0 g/L for HBA. Nevertheless, these compounds below their non-inhibitory concentrations jointly resulted in significant inhibition as a mixture. Catechol and phenol, which were persistent biotransformation products of the mixture, inhibited exoelectrogens at high concentrations, but to a lesser extent than the parent compounds. Recovery of exoelectrogenesis from inhibition by all compounds was observed, except for catechol, which resulted in irreversible inhibition. The reversibility of inhibition, as well as the observed difference in recovery rates, suggest different modes of exoelectrogenesis inhibition, related to the hydrophobicity of the inhibiting compounds.« less

Literature-based compound profiling: application to toxicogenomics.

PubMed

Frijters, Raoul; Verhoeven, Stefan; Alkema, Wynand; van Schaik, René; Polman, Jan

2007-11-01

To reduce continuously increasing costs in drug development, adverse effects of drugs need to be detected as early as possible in the process. In recent years, compound-induced gene expression profiling methodologies have been developed to assess compound toxicity, including Gene Ontology term and pathway over-representation analyses. The objective of this study was to introduce an additional approach, in which literature information is used for compound profiling to evaluate compound toxicity and mode of toxicity. Gene annotations were built by text mining in Medline abstracts for retrieval of co-publications between genes, pathology terms, biological processes and pathways. This literature information was used to generate compound-specific keyword fingerprints, representing over-represented keywords calculated in a set of regulated genes after compound administration. To see whether keyword fingerprints can be used for assessment of compound toxicity, we analyzed microarray data sets of rat liver treated with 11 hepatotoxicants. Analysis of keyword fingerprints of two genotoxic carcinogens, two nongenotoxic carcinogens, two peroxisome proliferators and two randomly generated gene sets, showed that each compound produced a specific keyword fingerprint that correlated with the experimentally observed histopathological events induced by the individual compounds. By contrast, the random sets produced a flat aspecific keyword profile, indicating that the fingerprints induced by the compounds reflect biological events rather than random noise. A more detailed analysis of the keyword profiles of diethylhexylphthalate, dimethylnitrosamine and methapyrilene (MPy) showed that the differences in the keyword fingerprints of these three compounds are based upon known distinct modes of action. Visualization of MPy-linked keywords and MPy-induced genes in a literature network enabled us to construct a mode of toxicity proposal for MPy, which is in agreement with known effects of MPy in literature. Compound keyword fingerprinting based on information retrieved from literature is a powerful approach for compound profiling, allowing evaluation of compound toxicity and analysis of the mode of action.

Method for loading lipsomes with ionizable phosphorylated hydrophobic compounds, pharmaceutical preparations and a method for administering the preparations

DOEpatents

Mehlhorn, Rolf Joachim

1998-10-27

A method of entrapping ionizable compounds, preferably phosphorylated hydrophobic compounds, into liposomes having transmembrane gradients is disclosed. The procedures involve forming liposomes in an acidic medium or a basic medium, adding to the acidic medium a cationic compound or to the basic medium an anionic compound and then adding a base to the cationic-containing medium or an acid to the anionic-containing medium, thereby inducing the ionizable compound into the liposomes' internal aqueous phase. The compound-entrapped liposomes prepared in accordance with the disclosed methods may be used as pharmaceutical preparations. Methods of administering such pharmaceutical preparations are also disclosed.

Radionuclide-binding compound, a radionuclide delivery system, a method of making a radium complexing compound, a method of extracting a radionuclide, and a method of delivering a radionuclide

DOEpatents

Fisher, Darrell R.; Wai, Chien M.; Chen, Xiaoyuan

2000-01-01

The invention pertains to compounds which specifically bind radionuclides, and to methods of making radionuclide complexing compounds. In one aspect, the invention includes a radionuclide delivery system comprising: a) a calix[n]arene-crown-[m]-ether compound, wherein n is an integer greater than 3, and wherein m is an integer greater than 3, the calix[n]arene-crown-[m]-ether compound comprising at least two ionizable groups; and b) an antibody attached to the calix[n]arene-crown-[m]-ether compound. In another aspect, the invention includes a method of making a radium complexing compound, comprising: a) providing a calix[n]arene compound, wherein n is an integer greater than 3, the calix[n]arene compound comprising n phenolic hydroxyl groups; b) providing a crown ether precursor, the crown ether precursor comprising a pair of tosylated ends; c) reacting the pair of tosylated ends with a pair of the phenolic hydroxyl groups to convert said pair of phenolic hydroxyl groups to ether linkages, the ether linkages connecting the crown ether precursor to the calix[n]arene to form a calix[n]arene-crown-[m]-ether compound, wherein m is an integer greater than 3; d) converting remaining phenolic hydroxyl groups to esters; e) converting the esters to acids, the acids being proximate a crown-[m]-ether portion of the calix[n]arene-crown-[m]-ether compound; and f) providing a Ra.sup.2+ ion within the crown-[m]-ether portion of the calix[n]arene-crown-[m]-ether compound.

Quantitative method of determining beryllium or a compound thereof in a sample

DOEpatents

McCleskey, T. Mark; Ehler, Deborah S.; John, Kevin D.; Burrell, Anthony K.; Collis, Gavin E.; Minogue, Edel M.; Warner, Benjamin P.

2006-10-31

A method of determining beryllium or a beryllium compound thereof in a sample, includes providing a sample suspected of comprising beryllium or a compound thereof, extracting beryllium or a compound thereof from the sample by dissolving in a solution, adding a fluorescent indicator to the solution to thereby bind any beryllium or a compound thereof to the fluorescent indicator, and determining the presence or amount of any beryllium or a compound thereof in the sample by measuring fluorescence.

Quantitative method of determining beryllium or a compound thereof in a sample

DOEpatents

McCleskey, T. Mark; Ehler, Deborah S.; John, Kevin D.; Burrell, Anthony K.; Collis, Gavin E.; Minogue, Edel M.; Warner, Benjamin P.

2010-08-24

A method of determining beryllium or a beryllium compound thereof in a sample, includes providing a sample suspected of comprising beryllium or a compound thereof, extracting beryllium or a compound thereof from the sample by dissolving in a solution, adding a fluorescent indicator to the solution to thereby bind any beryllium or a compound thereof to the fluorescent indicator, and determining the presence or amount of any beryllium or a compound thereof in the sample by measuring fluorescence.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Socha, Aaron; Singh, Seema; Simmons, Blake A.

Methods and compositions are provided for synthesizing ionic liquids from lignin derived compounds comprising: contacting a starting material comprising lignin with a depolymerization agent to depolymerize the lignin and form a mixture of aldehyde containing compounds; contacting the mixture of aldehyde containing compounds with an amine under conditions suitable to convert the mixture of aldehyde containing compounds to a mixture of amine containing compounds; and contacting the mixture of amine containing compounds with an acid under conditions suitable to form an ammonium salt, thereby preparing the ionic liquid.

Antifungal activity of schinol and a new biphenyl compound isolated from Schinus terebinthifolius against the pathogenic fungus Paracoccidioides brasiliensis.

PubMed

Johann, Susana; Sá, Nívea P; Lima, Luciana A R S; Cisalpino, Patricia S; Cota, Betania B; Alves, Tânia M A; Siqueira, Ezequias P; Zani, Carlos L

2010-10-12

The aim of this study was to isolate and identify the antifungal compounds from the extracts of Schinus terebinthifolius (Anacardiaceae) against clinical isolates of the pathogenic fungus Paracoccidioides brasiliensis. The hexane and dichlomethane fractions from leaves and stems of S. terebinthifolius were fractionated using several chromatography techniques to afford four compounds. The compounds isolated from S. terebinthifolius were identified as schinol (1), a new biphenyl compound, namely, 4'-ethyl-4-methyl-2,2',6,6'-tetrahydroxy[1,1'-biphenyl]-4,4'-dicarboxylate (2), quercetin (3), and kaempferol (4). Compounds 1 and 2 were active against different strains of P. brasiliensis, showing a minimal inhibitory concentration value against the isolate Pb B339 of 15.6 μg/ml. The isolate Pb 1578 was more sensitive to compound 1 with a MIC value of 7.5 μg/ml. Schinol presented synergistic effect only when combined with itraconazole. The compounds isolated from S. terebinthifolius were not able to inhibit cell wall synthesis or assembly using the sorbitol assay. This work reveals for the first time the occurrence of compound 2 and discloses activity of compounds 1 and 2 against several clinical isolates of P. brasiliensis. These results justify further studies to clarify the mechanisms of action of these compounds.

Just-in-Time Compound Pooling Increases Primary Screening Capacity without Compromising Screening Quality.

PubMed

Elkin, L L; Harden, D G; Saldanha, S; Ferguson, H; Cheney, D L; Pieniazek, S N; Maloney, D P; Zewinski, J; O'Connell, J; Banks, M

2015-06-01

Compound pooling, or multiplexing more than one compound per well during primary high-throughput screening (HTS), is a controversial approach with a long history of limited success. Many issues with this approach likely arise from long-term storage of library plates containing complex mixtures of compounds at high concentrations. Due to the historical difficulties with using multiplexed library plates, primary HTS often uses a one-compound-one-well approach. However, as compound collections grow, innovative strategies are required to increase the capacity of primary screening campaigns. Toward this goal, we have developed a novel compound pooling method that increases screening capacity without compromising data quality. This method circumvents issues related to the long-term storage of complex compound mixtures by using acoustic dispensing to enable "just-in-time" compound pooling directly in the assay well immediately prior to assay. Using this method, we can pool two compounds per well, effectively doubling the capacity of a primary screen. Here, we present data from pilot studies using just-in-time pooling, as well as data from a large >2-million-compound screen using this approach. These data suggest that, for many targets, this method can be used to vastly increase screening capacity without significant reduction in the ability to detect screening hits. © 2015 Society for Laboratory Automation and Screening.

The chemical nature of phenolic compounds determines their toxicity and induces distinct physiological responses in Saccharomyces cerevisiae in lignocellulose hydrolysates

PubMed Central

2014-01-01

We investigated the severity of the inhibitory effects of 13 phenolic compounds usually found in spruce hydrolysates (4-hydroxy-3-methoxycinnamaldehyde, homovanilyl alcohol, vanillin, syringic acid, vanillic acid, gallic acid, dihydroferulic acid, p-coumaric acid, hydroquinone, ferulic acid, homovanillic acid, 4-hydroxybenzoic acid and vanillylidenacetone). The effects of the selected compounds on cell growth, biomass yield and ethanol yield were studied and the toxic concentration threshold was defined for each compound. Using Ethanol Red, the popular industrial strain of Saccharomyces cerevisiae, we found the most toxic compound to be 4-hydroxy-3-methoxycinnamaldehyde which inhibited growth at a concentration of 1.8 mM. We also observed that toxicity did not generally follow a trend based on the aldehyde, acid, ketone or alcohol classification of phenolic compounds, but rather that other structural properties such as additional functional groups attached to the compound may determine its toxicity. Three distinctive growth patterns that effectively clustered all the compounds involved in the screening into three categories. We suggest that the compounds have different cellular targets, and that. We suggest that the compounds have different cellular targets and inhibitory mechanisms in the cells, also compounds who share similar pattern on cell growth may have similar inhibitory effect and mechanisms of inhibition. PMID:24949277

Extemporaneous compounding in veterinary practice: a New Zealand perspective.

PubMed

Gargiulo, D A; Chemal, C; Joda, L; Lee, Y J; Pilkington, M; Haywood, A; Garg, S

2013-11-01

The aims of this study were to explore the extent of extemporaneous compounding in veterinary centres throughout New Zealand and to determine whether pharmacists could collaborate with veterinarians to improve this service in New Zealand. Questionnaires were sent to 200 randomly selected veterinarians in New Zealand. Semi-structured interviews were also conducted with selected participants from four animal facilities (zoos, research facilities and animal shelters) and two compounding pharmacies. Of the 200 veterinarian questionnaire recipients, 99 responded. Ten replies were withdrawn from the study giving a response rate of 44.5%. Of these 89, 33 (37%) compounded in their practice. Of the 33 compounding professionals, 3 (9%) compounded daily for animals under their care; 11 (34%) weekly, 18 (54%) monthly and 1 (3%) compounded yearly. Compounding was done by 29/33 (88%) veterinarians, 16/33 (48%) veterinary nurses or 6/33 (18%) others. It was carried out due to the unavailability of commercial products, or the need for dose adjustment to ease administration or improve compliance. The animals most commonly requiring veterinary compounding were dogs (21/33; 64%), cats (19/33; 58%) or cattle (15/33; 46%). Products which were commonly compounded included cyclosporin eye drops, methimazole gels and potassium bromide solutions. Issues commonly faced when compounding included unavailability of dosage forms (18/33; 55%) or appropriate ingredients (14/33; 42%), stability (12/33; 36%), time constraints (10/33; 30%) or unavailability of equipment (9/33; 27%). Reasons given for not compounding included medicines being commercially available (38/56; 68%), pharmacy compounding for those particular practices (24/56; 43%), lack of training (21/56; 38%), ingredients (16/56; 29%) or equipment (15/56; 11%). All participants who worked with a pharmacist (11/33; 33%) described this relationship as beneficial and indicated they would continue to do so in the future. Veterinary extemporaneous compounding exists in New Zealand. As pharmacists have extensive knowledge in formulating medications and compounding they could be of greater value to veterinarians and their patients. Educating both professions on the opportunities available to them from this collaboration could be an important step forward. This study provides new information regarding extemporaneous compounding for veterinary patients in New Zealand.

Compositions containing borane or carborane cage compounds and related applications

DOEpatents

Bowen, III, Daniel E; Eastwood, Eric A

2013-05-28

Compositions comprising a polymer-containing matrix and a filler comprising a cage compound selected from borane cage compounds, carborane cage compounds, metal complexes thereof, residues thereof, mixtures thereof, and/or agglomerations thereof, where the cage compound is not covalently bound to the matrix polymer. Methods of making and applications for using such compositions are also disclosed.

Reading Compounds in Neglect Dyslexia: The Headedness Effect

ERIC Educational Resources Information Center

Semenza, Carlo; Arcara, Giorgio; Facchini, Silvia; Meneghello, Francesca; Ferraro, Marco; Passarini, Laura; Pilosio, Cristina; Vigato, Giovanna; Mondini, Sara

2011-01-01

Reading compound words was studied in neglect dyslexia in order to assess the influence of "headedness". The "head" of a compound is the component that determines the grammatical category, the syntactic (e.g., the gender) and the semantic properties of the compound as a whole. For example, in the word "blackberry" "berry" is the compound's head.…

Disruption of ion homeostasis by verrucosin and a related compound.

PubMed

Akiyama, Koichi; Tone, Junichi; Yamauchi, Satoshi; Sugahara, Takuya; Maruyama, Masafumi; Kakinuma, Yoshimi

2011-01-01

We have found that (-)-virgatusin and related compounds have antimicrobial and antifungal activity. To identify further biological activities of these compounds, we tested the activity of acridine orange efflux, which shows ionophore-like disruption of cellular ion homeostasis activity. After testing 31 compounds, we found that verrucosin and a related compound had disruption activity.

Tritium labeling of organic compounds deposited on porous structures

DOEpatents

Ehrenkaufer, Richard L. E.; Wolf, Alfred P.; Hembree, Wylie C.

1979-01-01

An improved process for labeling organic compounds with tritium is carried out by depositing the selected compound on the extensive surface of a porous structure such as a membrane filter and exposing the membrane containing the compound to tritium gas activated by the microwave discharge technique. The labeled compound is then recovered from the porous structure.

Compositions containing borane or carborane cage compounds and related applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowen, III, Daniel E; Eastwood, Eric A

2014-11-11

Compositions comprising a polymer-containing matrix and a filler comprising a cage compound selected from borane cage compounds, carborane cage compounds, metal complexes thereof, residues thereof, mixtures thereof, and/or agglomerations thereof, where the cage compound is not covalently bound to the matrix polymer. Methods of making and applications for using such compositions are also disclosed.

Compositions containing borane or carborane cage compounds and related applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowen, III, Daniel E.; Eastwood, Eric A.

2015-09-15

Compositions comprising a polymer-containing matrix and a filler comprising a cage compound selected from borane cage compounds, carborane cage compounds, metal complexes thereof, residues thereof, mixtures thereof, and/or agglomerations thereof, where the cage compound is not covalently bound to the matrix polymer. Methods of making and applications for using such compositions are also disclosed.

Development of volatile compounds during the manufacture of dry-cured "lacón," a Spanish traditional meat product.

PubMed

Purriños, Laura; Bermúdez, Roberto; Franco, Daniel; Carballo, Javier; Lorenzo, José M

2011-01-01

Volatile compounds were determined throughout the manufacture of dry-cured "lacón," a traditional dry-salted, and ripened meat product made in the north-west of Spain from the foreleg of the pig following a similar process to that of dry-cured ham. Volatiles were extracted by a purge-and-trap method and analyzed by gas chromatographic/mass spectrometry. One hundred and two volatile compounds were identified. In raw material, only 34 volatile compounds were found and at very low levels. The number of volatile compounds increased during processing. The substances identified belonged to several chemical classes: aldehydes (23), alcohols (9), ketones (15), hydrocarbons (37), esters (4), acids (3), furans (4), sulphur compounds (1), chloride compounds (1), and other compounds (4). Results indicated that the most abundant chemical family in flavor at the end of the manufacturing process was aldehydes, followed by hydrocarbons and ketones. Lipids were the most important precursor of flavor compounds of dry-cured "lacón."

Olfactometric determination of the most potent odor-active compounds in salmon muscle (Salmo salar) smoked by using four smoke generation techniques.

PubMed

Varlet, Vincent; Serot, Thierry; Cardinal, Mireille; Knockaert, Camille; Prost, Carole

2007-05-30

The volatile compounds of salmon fillets smoked according to four smoked generation techniques (smoldering, thermostated plates, friction, and liquid smoke) were investigated. The main odor-active compounds were identified by gas chromatography coupled with olfactometry and mass spectrometry. Only the odorant volatile compounds detected by at least six judges (out of eight) were identified as potent odorants. Phenolic compounds and guaiacol derivatives were the most detected compounds in the olfactometric profile whatever the smoking process and could constitute the smoky odorant skeleton of these products. They were recovered in the aromatic extracts of salmon smoked by smoldering and by friction, which were characterized by 18 and 25 odor-active compounds, respectively. Furannic compounds were more detected in products smoked with thermostated plates characterized by 26 odorants compounds. Finally, the 27 odorants of products treated with liquid smoke were significantly different from the three others techniques applying wood pyrolysis because pyridine derivatives and lipid oxidation products were perceived in the aroma profile.

Synthesis of new 1,2,4-triazole compounds containing Schiff and Mannich bases (morpholine) with antioxidant and antimicrobial activities.

PubMed

Ünver, Yasemin; Deniz, Sadik; Çelik, Fatih; Akar, Zeynep; Küçük, Murat; Sancak, Kemal

2016-01-01

Compound 2 was synthesized by reacting CS 2 /KOH with compound 1. The treatment of compound 2 with hydrazine hydrate produced compound 3. Then, compound 3 was converted to Schiff bases (4a-d) by the handling with several aromatic aldehydes. The treatment of triazole compounds 4a-d containing Schiff base with morpholine gave compounds 5a-d. All compounds were tested for their antioxidant and antimicrobial activities. The antioxidant test results of DPPH• radical scavenging and ferric reducing/antioxidant power methods showed good antioxidant activity. The triazole-thiol (3) was the most active, and the effect of the substituent type of the thiophene ring on the activity was same for both Schiff bases (4a-d) and Mannich bases (5a-d). Among the newly synthesized triazole derivatives, the Schiff base 4d and the Mannich base 5d carrying nitro substituent on the thiophene ring showed promising antibacterial and antifungal activity, with lower MIC values than the standard antibacterial ampicillin.

Identification of nonvolatile compounds in clove (Syzygium aromaticum) from Manado

NASA Astrophysics Data System (ADS)

Fathoni, A.; Saepudin, E.; Cahyana, A. H.; Rahayu, D. U. C.; Haib, J.

2017-07-01

Syzygium aromaticum (clove) are native to Indonesia and have been widely used in food industry due to their flavor. Nonvolatile compounds contribute to flavor, mainly in their taste. Currently, there is very little information available about nonvolatile compounds in clove. Identification of nonvolatile compounds is important to improve clove's value. Compound extraction was conducted by maceration in ethanol. Fractionations of the extract were performed by using gravity column chromatography on silica gel and Sephadex LH-20 as stationary phase. Nonvolatile compounds were identified by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS). LC-MS/MS was operated in negative mode with 0.1 % formic acid in water and acetonitrile as mobile phase. Nonvolatile compounds were identified by fragment analysis and compared to references. Several compounds had been identified and characterized asquinic acid, monogalloylglucose, gallic acid, digalloylglucose, isobiflorin, biflorin, ellagic acid, hydroxygallic acid, luteolin, quercetin, naringenin, kaempferol, isorhamnetin, dimethoxyluteolin, and rhamnetin. These compounds had two main flavor perceptions, i.e. astringent, and bitter.

COMDECOM: predicting the lifetime of screening compounds in DMSO solution.

PubMed

Zitha-Bovens, Emrin; Maas, Peter; Wife, Dick; Tijhuis, Johan; Hu, Qian-Nan; Kleinöder, Thomas; Gasteiger, Johann

2009-06-01

The technological evolution of the 1990s in both combinatorial chemistry and high-throughput screening created the demand for rapid access to the compound deck to support the screening process. The common strategy within the pharmaceutical industry is to store the screening library in DMSO solution. Several studies have shown that a percentage of these compounds decompose in solution, varying from a few percent of the total to a substantial part of the library. In the COMDECOM (COMpound DECOMposition) project, the compound stability of screening compounds in DMSO solution is monitored in an accelerated thermal, hydrolytic, and oxidative decomposition program. A large database with stability data is collected, and from this database, a predictive model is being developed. The aim of this program is to build an algorithm that can flag compounds that are likely to decompose-information that is considered to be of utmost importance (e.g., in the compound acquisition process and when evaluation screening results of library compounds, as well as in the determination of optimal storage conditions).

Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride carbide and carbonitride

DOEpatents

Wong, M.S.; Li, D.; Chung, Y.W.; Sproul, W.D.; Xi Chu; Barnett, S.A.

1998-03-10

A composite material having high hardness comprises a carbon nitrogen compound, such as CN{sub x} where x is greater than 0.1 and up to 1.33, deposited on a metal or metal compound selected to promote deposition of substantially crystalline CN{sub x}. The carbon nitrogen compound is deposited on a crystal plane of the metal or metal compound sufficiently lattice-matched with a crystal plane of the carbon nitrogen compound that the carbon nitrogen compound is substantially crystalline. A plurality of layers of the compounds can be formed in alternating sequence to provide a multi-layered, superlattice coating having a coating hardness in the range of 45--55 GPa, which corresponds to the hardness of a BN coating and approaches that of a diamond coating. 10 figs.

Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride, carbide and carbonitride

DOEpatents

Wong, M.S.; Li, D.; Chung, Y.W.; Sproul, W.D.; Chu, X.; Barnett, S.A.

1998-07-07

A composite material having high hardness comprises a carbon nitrogen compound, such as CN{sub x} where x is greater than 0.1 and up to 1.33, deposited on a metal or metal compound selected to promote deposition of substantially crystalline CN{sub x}. The carbon nitrogen compound is deposited on a crystal plane of the metal or metal compound sufficiently lattice-matched with a crystal plane of the carbon nitrogen compound that the carbon nitrogen compound is substantially crystalline. A plurality of layers of the compounds can be formed in alternating sequence to provide a multi-layered, superlattice coating having a coating hardness in the range of 45--55 GPa, which corresponds to the hardness of a BN coating and approaches that of a diamond coating. 10 figs.

Energy and Biocides Storage Compounds: Synthesis and Characterization of Energetic Bridged Bis(triiodoazoles).

PubMed

He, Chunlin; Zhao, Gang; Hooper, Joseph P; Shreeve, Jean'ne M

2017-11-06

Energetic bridged triiodopyrazoles and triiodoimidazoles were designed and synthsized by reacting potassium triiodopyrazolate or triiodoimidazolate with corresponding dichloro compounds. All compounds were fully characterized by 1 H and 13 C NMR spectroscopy, IR spectroscopy, and elemental analyses. The structure of compound 1 was further confirmed by single-crystal X-ray diffraction. All of the compounds exhibit good thermal stability with decomposition temperatures between 199 and 270 °C and high densities ranging from 2.804 to 3.358 g/cm 3 . The detonation performances and the detonation products were calculated by CHEETAH 7. Compound 3 (D v = 4765 m s -1 ; P = 17.9 GPa) and compound 7 (D v = 4841 m s -1 ; P = 18.5 GPa) show comparable detonation pressure to TNT, and high iodine content makes them promising as energy and biocides storage compounds.

Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride, carbide and carbonitride

DOEpatents

Wong, Ming-Show; Li, Dong; Chung, Yip-Wah; Sproul, William D.; Chu, Xi; Barnett, Scott A.

1998-01-01

A composite material having high hardness comprises a carbon nitrogen compound, such as CN.sub.x where x is greater than 0.1 and up to 1.33, deposited on a metal or metal compound selected to promote deposition of substantially crystalline CN.sub.x. The carbon nitrogen compound is deposited on a crystal plane of the metal or metal compound sufficiently lattice-matched with a crystal plane of the carbon nitrogen compound that the carbon nitrogen compound is substantially crystalline. A plurality of layers of the compounds can be formed in alternating sequence to provide a multi-layered, superlattice coating having a coating hardness in the range of 45-55 GPa, which corresponds to the hardness of a BN coating and approaches that of a diamond coating.

Superhard composite materials including compounds of carbon and nitrogen deposited on metal and metal nitride carbide and carbonitride

DOEpatents

Wong, Ming-Show; Li, Dong; Chung, Yin-Wah; Sproul, William D.; Chu, Xi; Barnett, Scott A.

1998-01-01

A composite material having high hardness comprises a carbon nitrogen compound, such as CN.sub.x where x is greater than 0.1 and up to 1.33, deposited on a metal or metal compound selected to promote deposition of substantially crystalline CN.sub.x. The carbon nitrogen compound is deposited on a crystal plane of the metal or metal compound sufficiently lattice-matched with a crystal plane of the carbon nitrogen compound that the carbon nitrogen compound is substantially crystalline. A plurality of layers of the compounds can be formed in alternating sequence to provide a multi-layered, superlattice coating having a coating hardness in the range of 45-55 GPa, which corresponds to the hardness of a BN coating and approaches that of a diamond coating.

New ligand-based approach for the discovery of antitrypanosomal compounds.

PubMed

Vega, María Celeste; Montero-Torres, Alina; Marrero-Ponce, Yovani; Rolón, Miriam; Gómez-Barrio, Alicia; Escario, José Antonio; Arán, Vicente J; Nogal, Juan José; Meneses-Marcel, Alfredo; Torrens, Francisco

2006-04-01

The antitrypanosomal activity of 10 already synthesized compounds was in silico predicted as well as in vitro and in vivo explored against Trypanosoma cruzi. For the computational study, an approach based on non-stochastic linear fingerprints to the identification of potential antichagasic compounds is introduced. Molecular structures of 66 organic compounds, 28 with antitrypanosomal activity and 38 having other clinical uses, were parameterized by means of the TOMOCOMD-CARDD software. A linear classification function was derived allowing the discrimination between active and inactive compounds with a confidence of 95%. As predicted, seven compounds showed antitrypanosomal activity (%AE>70) against epimastigotic forms of T. cruzi at a concentration of 100mug/mL. After an unspecific cytotoxic assay, three compounds were evaluated against amastigote forms of the parasite. An in vivo test was carried out for one of the studied compounds.

A New Bayesian Approach for Estimating the Presence of a Suspected Compound in Routine Screening Analysis.

PubMed

Woldegebriel, Michael; Vivó-Truyols, Gabriel

2016-10-04

A novel method for compound identification in liquid chromatography-high resolution mass spectrometry (LC-HRMS) is proposed. The method, based on Bayesian statistics, accommodates all possible uncertainties involved, from instrumentation up to data analysis into a single model yielding the probability of the compound of interest being present/absent in the sample. This approach differs from the classical methods in two ways. First, it is probabilistic (instead of deterministic); hence, it computes the probability that the compound is (or is not) present in a sample. Second, it answers the hypothesis "the compound is present", opposed to answering the question "the compound feature is present". This second difference implies a shift in the way data analysis is tackled, since the probability of interfering compounds (i.e., isomers and isobaric compounds) is also taken into account.

Production of rare ginsenosides (compound Mc, compound Y and aglycon protopanaxadiol) by β-glucosidase from Dictyoglomus turgidum that hydrolyzes β-linked, but not α-linked, sugars in ginsenosides.

PubMed

Lee, Gi-Woong; Kim, Kyoung-Rok; Oh, Deok-Kun

2012-09-01

Optimal hydrolytic activity of β-glucosidase from Dictyoglomus turgidum for the ginsenoside Rd was at pH 5.5 and 80 °C, with a half-life of ~11 h. The enzyme hydrolysed β-linked, but not α-linked, sugar moieties of ginsenosides. It produced the rare ginsenosides, aglycon protopanaxadiol (APPD), compounds Y, and Mc, via three unique transformation pathways: Rb(1) → Rd → F(2) → compound K → APPD, Rb(2) → compound Y, and Rc → compound Mc. The enzyme converted 0.5 mM Rb(2) and 0.5 mM Rc to 0.5 mM compound Y and 0.5 mM compound Mc after 3 h, respectively, with molar conversion yields of 100 %.

Synthesis, Antiinflammatory and Antimicrobial Activity of Some New 1-(3-Phenyl-3,4-Dihydro-2H-1,3-Benzoxazin-6-yl)-Ethanone Derivatives

PubMed Central

Akhter, Mymoona; Husain, A.; Akhter, N.; Khan, M. S. Y

2011-01-01

Synthesis of title compounds (4a-j) was carried out by following aminomethylation Mannich reaction. Test compounds were effective in inhibiting edema induced by carrageenan. The percent inhibition obseved was in the range of 25-83.3%. Compound (4c, e, h and j) were also tested for analgesic effect and showed percent protection ranging between 57-65%. All the synthesized compounds were active against E. coli and S. aureus but only compounds (4 b, c, e, i and j) were active against B. subtilis. All these compound were also found active against A. niger. Compound 4j was the most active compound with 83.3% inhibition of edema, 65.35% percent protection and inhibited all the three bacterial strains. PMID:22131632

Analysis of Relative Concentration of Ethanol and Other Odorous Compounds (OCs) Emitted from the Working Surface at a Landfill in China

PubMed Central

Li, Dong; Lu, Wenjing; Liu, Yanjun; Guo, Hanwen; Xu, Sai; Ming, Zhongyuan; Wang, Hongtao

2015-01-01

Estimating odor emissions from landfill sites is a complicated task because of the various chemical and biological species that exist in landfill gases. In this study, the relative concentration of ethanol and other odorous compounds emitted from the working surface at a landfill in China was analyzed. Gas sampling was conducted at the landfill on a number of selected days from March 2012 to March 2014, which represented different periods throughout the two years. A total of 41, 59, 66, 54, 63, 54, 41, and 42 species of odorous compounds were identified and quantified in eight sampling activities, respectively; a number of 86 species of odorous compounds were identified and quantified all together in the study. The measured odorous compounds were classified into six different categories (Oxygenated compounds, Halogenated compounds, Terpenes, Sulfur compounds, Aromatics, and Hydrocarbons). The total average concentrations of the oxygenated compounds, sulfur compounds, aromatics, halogenated compounds, hydrocarbons, and terpenes were 2.450 mg/m3, 0.246 mg/m3, 0.203 mg/m3, 0.319 mg/m3, 0.530 mg/m3, and 0.217 mg/m3, respectively. The relative concentrations of 59 odorous compounds with respect to the concentration of ethyl alcohol (1000 ppm) were determined. The dominant contaminants that cause odor pollution around the landfill are ethyl sulfide, methyl mercaptan, acetaldehyde, and hydrogen sulfide; dimethyl disulfide and dimethyl sulfide also contribute to the pollution to a certain degree. PMID:25769100

Antitumor activity of a novel and orally available inhibitor of serine palmitoyltransferase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yaguchi, Masahiro; Shibata, Sachio; Satomi, Yoshinori

Metabolic reprogramming is an essential hallmark of neoplasia. Therefore, targeting cancer metabolism, including lipid synthesis, has attracted much interest in recent years. Serine palmitoyltransferase (SPT) plays a key role in the initial and rate-limiting step of de novo sphingolipid biosynthesis, and inhibiting SPT activity prevents the proliferation of certain cancer cells. Here, we identified a novel and orally available SPT inhibitor, compound-2. Compound-2 showed an anti-proliferative effect in several cancer cell models, reducing the levels of the sphingolipids ceramide and sphingomyelin. In the presence of compound-2, exogenously added S1P partially compensated the intracellular sphingolipid levels through the salvage pathway bymore » partially rescuing compound-2-induced cytotoxicity. This suggested that the mechanism underlying the anti-proliferative effect of compound-2 involved the reduction of sphingolipid levels. Indeed, compound-2 promoted multinuclear formation with reduced endogenous sphingomyelin levels specifically in a compound-2-sensitive cell line, indicating that the effect was induced by sphingolipid reduction. Furthermore, compound-2 showed potent antitumor activity without causing significant body weight loss in the PL-21 acute myeloid leukemia mouse xenograft model. Therefore, SPT may be an attractive therapeutic anti-cancer drug target for which compound-2 may be a promising new drug. - Highlights: • We discovered compound-2, a novel and orally available SPT inhibitor. • Compound-2 was cytotoxic against PL-21 acute myeloid leukemia cells. • Compound-2 showed antitumor activity in the PL-21 mouse xenograft model.« less

Semantically Transparent and Opaque Compounds in German Noun-Phrase Production: Evidence for Morphemes in Speaking.

PubMed

Lorenz, Antje; Zwitserlood, Pienie

2016-01-01

This study examines the lexical representation and processing of noun-noun compounds and their grammatical gender during speech production in German, a language that codes for grammatical gender (masculine, feminine, and neuter). Using a picture-word interference paradigm, participants produced determiner-compound noun phrases in response to pictures, while ignoring written distractor words. Compound targets were either semantically transparent (e.g., birdhouse) or opaque (e.g., hotdog), and their constituent nouns either had the same or a different gender (internal gender match). Effects of gender-congruent but otherwise unrelated distractor nouns, and of two morphologically related distractors corresponding to the first or second constituent were assessed relative to a completely unrelated, gender-incongruent distractor baseline. Both constituent distractors strongly facilitated compound naming, and these effects were independent of the targets' semantic transparency. This supports retrieval of constituent morphemes for semantically transparent and opaque compounds during speech production. Furthermore, gender congruency between compounds and distractors did not speed up naming in general, but interacted with gender match of the compounds' constituent nouns, and their semantic transparency. A significant gender-congruency effect was obtained with semantically transparent compounds, consisting of two constituent nouns of the same gender, only. In principle, this pattern is compatible with a multiple lemma representation account for semantically transparent, but not for opaque compounds. The data also fit with a more parsimonious, holistic representation for all compounds at the lemma level, when differences in co-activation patterns for semantically transparent and opaque compounds are considered.

Practices of pharmacies that compound extemporaneous formulations.

PubMed

Treadway, Angela K; Craddock, Deeatra; Leff, Richard

2007-07-01

A survey was conducted to characterize the standard of practice for extemporaneous pharmaceutical compounding within community and institutional pharmacies. Extemporaneous compounding practices vary among pharmacies. Because of this, the survey inquired specifically about a single pharmaceutical product (caffeine citrate 20 mg/mL) to minimize variability among respondents. Survey questions were written to identify compounding practice variations with (1) policies and procedures, (2) process validation, (3) personnel education, training, and evaluation, (4) expiration dating, (5) storage and handling of compounded prescriptions within the pharmacy, (6) labeling, (7) facilities and equipment, (8) end-product evaluation, (9) handling of sterile products outside of the pharmacy, (10) aseptic technique and product preparation, and (11) documentation. A total of 522 surveys were mailed; 117 completed surveys were returned and included in the analyses. Over half of the pharmacies surveyed were large institutional pharmacies with daily prescriptions exceeding 300. Almost 71% of pharmacies reported having policies and procedures for compounding and providing compounding training for staff. Almost one third of the pharmacies that responded did not have compounding policies and procedures and did not provide staff training. For those pharmacies that provided training, the methods used were diverse (e.g., lectures and videotapes, external certificate programs). Formulations used to compound caffeine appeared to be diverse as evidenced by the varied addition of inactive ingredients. A survey of compounding pharmacies found variability in overall compounding practices and training and in practices specifically related to compounding preparations of caffeine citrate.

Occurrence of Organic Wastewater Compounds in Selected Surface-Water Supplies, Triangle Area of North Carolina, 2002-2005

USGS Publications Warehouse

Giorgino, M.J.; Rasmussen, R.B.; Pfeifle, C.M .

2007-01-01

Selected organic wastewater compounds, such as household, industrial, and agricultural-use compounds, sterols, pharmaceuticals, and antibiotics, were measured at eight sites classified as drinking-water supplies in the Triangle Area of North Carolina. From October 2002 through July 2005, seven of the sites were sampled twice, and one site was sampled 28 times, for a total of 42 sets of environmental samples. Samples were analyzed for as many as 126 compounds using three laboratory analytical methods. These methods were developed by the U.S. Geological Survey to detect low levels (generally less than or equal to 1.0 microgram per liter) of the target compounds in filtered water. Because analyses were conducted on filtered samples, the results presented in this report may not reflect the total concentration of organic wastewater compounds in the waters that were sampled. Various quality-control samples were used to quality assure the results in terms of method performance and possible laboratory or field contamination. Of the 108 organic wastewater compounds that met method performance criteria, 24 were detected in at least one sample during the study. These 24 compounds included 3 pharmaceutical compounds, 6 fire retardants and plasticizers, 3 antibiotics, 3 pesticides, 6 fragrances and flavorants, 1 disinfectant, and 2 miscellaneous-use compounds, all of which likely originated from a variety of domestic, industrial, and agricultural sources. The 10 most frequently detected compounds included acetyl-hexamethyl tetrahydronaphthalene and hexahydro-hexamethyl cyclopentabenzopyran (synthetic musks that are widely used in personal-care products and are known endocrine disruptors); tri(2-chloroethyl) phosphate, tri(dichloroisopropyl) phosphate, and tributyl phosphate (fire retardants); metolachlor (herbicide); caffeine (nonprescription stimulant); cotinine (metabolite of nicotine); acetaminophen (nonprescription analgesic); and sulfamethoxazole (prescription antibiotic). The occurrence and distribution of organic wastewater compounds varied considerably among sampling sites, but at least one compound was detected at every location. The most organic wastewater compounds (19) were detected at the Neuse River above U.S. 70 at Smithfield, where two-thirds of the total number of samples were collected. The fewest organic wastewater compounds (1) were detected at the Eno River at Hillsborough. The detection of multiple organic wastewater compounds was common, with a median of 3.5 and as many as 12 compounds observed in individual samples. Some compounds, including acetaminophen, cotinine, tri(2-chloroethyl) phosphate, and metolachlor, were detected at numerous sites and in numerous samples, indicating that they are widely distributed in the environment. Other organic wastewater compounds, including acetyl-hexamethyl tetrahydronaphthalene and hexahydro-hexamethyl cyclopentabenzopyran, were detected in numerous samples but at only one location, indicating that sources of these compounds are more site specific. Results indicate that municipal wastewater may be a source of antibiotics and synthetic musks; however, the three sites in this study that are located downstream from wastewater discharges also receive runoff from agricultural, urban, and rural residential lands. Source identification was not an objective of this study. Concentrations of individual compounds generally were less than 0.5 microgram per liter. No concentrations exceeded Federal drinking-water standards or health advisories, nor water-quality criteria established by the State of North Carolina; however, such criteria are available for only a few of the compounds that were studied. Compared with other surface waters that have been sampled across the United States, the Triangle Area water-supply sites had fewer detections of organic wastewater compounds; however, differences in study design and analytical methods used among studies must be considered when mak

Is free halogen necessary for disinfection?

PubMed Central

Williams, D E; Elder, E D; Worley, S D

1988-01-01

The principle of Le Chatelier was used in demonstrating that 3-chloro-4,4-dimethyl-2-oxazolidinone (compound 1) itself kills Staphylococcus aureus rather than the very small amount of free chlorine in hydrolysis equilibrium with compound 1. On the other hand, when the N-bromo analog of compound 1 (compound 1B) was used as the disinfectant, the mixture of combined compound 1B and free bromine formed in the hydrolysis equilibrium provided disinfection. When the hydrolysis equilibrium for 1B was suppressed to the level at which a negligible amount of free bromine remained in solution, combined compound 1B was much more efficacious than combined compound 1 at killing S. aureus. PMID:3202636

Is free halogen necessary for disinfection?

PubMed

Williams, D E; Elder, E D; Worley, S D

1988-10-01

The principle of Le Chatelier was used in demonstrating that 3-chloro-4,4-dimethyl-2-oxazolidinone (compound 1) itself kills Staphylococcus aureus rather than the very small amount of free chlorine in hydrolysis equilibrium with compound 1. On the other hand, when the N-bromo analog of compound 1 (compound 1B) was used as the disinfectant, the mixture of combined compound 1B and free bromine formed in the hydrolysis equilibrium provided disinfection. When the hydrolysis equilibrium for 1B was suppressed to the level at which a negligible amount of free bromine remained in solution, combined compound 1B was much more efficacious than combined compound 1 at killing S. aureus.

Method for loading lipsomes with ionizable phosphorylated hydrophobic compounds, pharmaceutical preparations and a method for administering the preparations

DOEpatents

Mehlhorn, R.J.

1998-10-27

A method of entrapping ionizable compounds, preferably phosphorylated hydrophobic compounds, into liposomes having transmembrane gradients is disclosed. The procedures involve forming liposomes in an acidic medium or a basic medium, adding to the acidic medium a cationic compound or to the basic medium an anionic compound and then adding a base to the cationic-containing medium or an acid to the anionic-containing medium, thereby inducing the ionizable compound into the liposomes` internal aqueous phase. The compound-entrapped liposomes prepared in accordance with the disclosed methods may be used as pharmaceutical preparations. Methods of administering such pharmaceutical preparations are also disclosed. 2 figs.

Enhanced formulations for neutralization of chemical, biological and industrial toxants

DOEpatents

Tucker, Mark D [Albuqueque, NM

2008-06-24

An enhanced formulation and method of making that neutralizes the adverse health effects of both chemical and biological compounds, especially chemical warfare (CW) and biological warfare (BW) agents, and toxic industrial chemicals. The enhanced formulation according to the present invention is non-toxic and non-corrosive and can be delivered by a variety of means and in different phases. The formulation provides solubilizing compounds that serve to effectively render the chemical and biological compounds, particularly CW and BW compounds, susceptible to attack, and at least one reactive compound that serves to attack (and detoxify or kill) the compound. The formulation includes at least one solubilizing agent, a reactive compound, a bleaching activator and water.

Organic electronic devices using phthalimide compounds

DOEpatents

Hassan, Azad M.; Thompson, Mark E.

2010-09-07

Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

Organic electronic devices using phthalimide compounds

DOEpatents

Hassan, Azad M.; Thompson, Mark E.

2012-10-23

Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

Organic electronic devices using phthalimide compounds

DOEpatents

Hassan, Azad M.; Thompson, Mark E.

2013-03-19

Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

Process for preparing phthalocyanine polymer from imide containing bisphthalonitrile

NASA Technical Reports Server (NTRS)

Achar, Bappalige N. (Inventor); Fohlen, George M. (Inventor); Parker, John A. (Inventor)

1987-01-01

Imide-linked bisphthalonitrile compounds are prepared by combining a dicyano aromatic diamine and an organic dianhydride to produce an amic acid linked bisphthalonitrile compound. The amic acid linked bisphthalonitrile compound is dehydrocyclized to produce the imide-linked bisphthalonitrile compounds. The imide-linked bisphthalonitrile compounds may be polymerized to produce a phythalocyanine polymer by heating the imide-linked bisphthalonitrile compound, either alone or in the presence of a metal powder or a metal salt. These compounds are useful in the coating, laminating and molding arts. The polymers are useful in composite matrix resins where increased fire resistance, toughness and resistance to moisture are required, particularly as secondary structures in aircraft and spacecraft.

Deuterium permeation through EPDM rubber compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zapp, P.E.

1988-01-01

The permeation of deuterium through a specially formulated compound of ethylene propylene diene rubber was measured in the temperature range of 26/degree/C to 120/degree/C. The results were similar to permeation through two commercial compounds of this elastomer. Permeation was reduced after gamma irradiation (in the presence of hydrogen gas to simulate a tritium exposure). However the reduction was smaller than that experienced by the two commercial compounds. Radiation damage is apparently less severe in the special compound. It is possible that mechanical properties such as compression set may be influenced less by ionizing radiation in this compound as compared withmore » the commercial compounds. 4 figs., 1 tab.« less

Prioritizing pesticide compounds for analytical methods development

USGS Publications Warehouse

Norman, Julia E.; Kuivila, Kathryn; Nowell, Lisa H.

2012-01-01

The U.S. Geological Survey (USGS) has a periodic need to re-evaluate pesticide compounds in terms of priorities for inclusion in monitoring and studies and, thus, must also assess the current analytical capabilities for pesticide detection. To meet this need, a strategy has been developed to prioritize pesticides and degradates for analytical methods development. Screening procedures were developed to separately prioritize pesticide compounds in water and sediment. The procedures evaluate pesticide compounds in existing USGS analytical methods for water and sediment and compounds for which recent agricultural-use information was available. Measured occurrence (detection frequency and concentrations) in water and sediment, predicted concentrations in water and predicted likelihood of occurrence in sediment, potential toxicity to aquatic life or humans, and priorities of other agencies or organizations, regulatory or otherwise, were considered. Several existing strategies for prioritizing chemicals for various purposes were reviewed, including those that identify and prioritize persistent, bioaccumulative, and toxic compounds, and those that determine candidates for future regulation of drinking-water contaminants. The systematic procedures developed and used in this study rely on concepts common to many previously established strategies. The evaluation of pesticide compounds resulted in the classification of compounds into three groups: Tier 1 for high priority compounds, Tier 2 for moderate priority compounds, and Tier 3 for low priority compounds. For water, a total of 247 pesticide compounds were classified as Tier 1 and, thus, are high priority for inclusion in analytical methods for monitoring and studies. Of these, about three-quarters are included in some USGS analytical method; however, many of these compounds are included on research methods that are expensive and for which there are few data on environmental samples. The remaining quarter of Tier 1 compounds are high priority as new analytes. The objective for analytical methods development is to design an integrated analytical strategy that includes as many of the Tier 1 pesticide compounds as possible in a relatively few, cost-effective methods. More than 60 percent of the Tier 1 compounds are high priority because they are anticipated to be present at concentrations approaching levels that could be of concern to human health or aquatic life in surface water or groundwater. An additional 17 percent of Tier 1 compounds were frequently detected in monitoring studies, but either were not measured at levels potentially relevant to humans or aquatic organisms, or do not have benchmarks available with which to compare concentrations. The remaining 21 percent are pesticide degradates that were included because their parent pesticides were in Tier 1. Tier 1 pesticide compounds for water span all major pesticide use groups and a diverse range of chemical classes, with herbicides and their degradates composing half of compounds. Many of the high priority pesticide compounds also are in several national regulatory programs for water, including those that are regulated in drinking water by the U.S. Environmental Protection Agency under the Safe Drinking Water Act and those that are on the latest Contaminant Candidate List. For sediment, a total of 175 pesticide compounds were classified as Tier 1 and, thus, are high priority for inclusion in analytical methods available for monitoring and studies. More than 60 percent of these compounds are included in some USGS analytical method; however, some are spread across several research methods that are expensive to perform, and monitoring data are not extensive for many compounds. The remaining Tier 1 compounds for sediment are high priority as new analytes. The objective for analytical methods development for sediment is to enhance an existing analytical method that currently includes nearly half of the pesticide compounds in Tier 1 by adding as many additional Tier 1 compounds as are analytically compatible. About 35 percent of the Tier 1 compounds for sediment are high priority on the basis of measured occurrence. A total of 74 compounds, or 42 percent, are high priority on the basis of predicted likelihood of occurrence according to physical-chemical properties, and either have potential toxicity to aquatic life, high pesticide useage, or both. The remaining 22 percent of Tier 1 pesticide compounds were either degradates of Tier 1 parent compounds or included for other reasons. As with water, the Tier 1 pesticide compounds for sediment are distributed across the major pesticide-use groups; insecticides and their degradates are the largest fraction, making up 45 percent of Tier 1. In contrast to water, organochlorines, at 17 percent, are the largest chemical class for Tier 1 in sediment, which is to be expected because there is continued widespread detection in sediments of persistent organochlorine pesticides and their degradates at concentrations high enough for potential effects on aquatic life. Compared to water, there are fewer available benchmarks with which to compare contaminant concentrations in sediment, but a total of 19 Tier 1 compounds have at least one sediment benchmark or screening value for aquatic organisms. Of the 175 compounds in Tier 1, 77 percent have high aquatic-life toxicity, as defined for this process. This evaluation of pesticides and degradates resulted in two lists of compounds that are priorities for USGS analytical methods development, one for water and one for sediment. These lists will be used as the basis for redesigning and enhancing USGS analytical capabilities for pesticides in order to capture as many high-priority pesticide compounds as possible using an economically feasible approach.

In situ catalytic hydrogenation of model compounds and biomass-derived phenolic compounds for bio-oil upgrading

Treesearch

Junfeng Feng; Zhongzhi Yang; Chung-yun Hse; Qiuli Su; Kui Wang; Jianchun Jiang; Junming Xu

2017-01-01

The renewable phenolic compounds produced by directional liquefaction of biomass are a mixture of complete fragments decomposed from native lignin. These compounds are unstable and difficult to use directly as biofuel. Here, we report an efficient in situ catalytic hydrogenation method that can convert phenolic compounds into saturated cyclohexanes. The process has...

The Mental Representation of Verb-Noun Compounds in Italian: Evidence from a Multiple Single-Case Study in Aphasia

ERIC Educational Resources Information Center

Mondini, Sara; Luzzatti, Claudio; Zonca, Giusy; Pistarini, Caterina; Semenza, Carlo

2004-01-01

This study seeks information on the mental representation of Verb-Noun (VN) nominal compounds through neuropsychological methods. The lexical retrieval of compound nouns is tested in 30 aphasic patients using a visual confrontation naming task. The target names are VN compounds, Noun-Noun (NN) compounds, and long morphologically simple nouns…

Targeting the epigenome: Screening bioactive compounds that regulate histone deacetylase activity

PubMed Central

Godoy, Luis D.; Lucas, Julianna E.; Bender, Abigail J.; Romanick, Samantha S.; Ferguson, Bradley S.

2017-01-01

Scope Nutrigenomics is a rapidly expanding field that elucidates the link between diet-genome interactions. Recent evidence demonstrates that regulation of the epigenome, and in particular inhibition of HDACs, impact pathogenetic mechanisms involved in chronic disease. Few studies, to date, have screened libraries of bioactive compounds that act as epigenetic modifiers. This study screened a library of 131 natural compounds to determine bioactive compounds that inhibit Zn-dependent HDAC activity. Methods and results Using class-specific HDAC substrates, we screened 131 natural compounds for HDAC activity in bovine cardiac tissue. From this screen, we identified 18 bioactive compound HDAC inhibitors. Using our class-specific HDAC substrates, we next screened these 18 bioactive compounds against recombinant HDAC proteins. Consistent with inhibition of HDAC activity, these compounds were capable of inhibiting activity of individual HDAC isoforms. Lastly, we report that treatment of H9c2 cardiac myoblasts with bioactive HDAC inhibitors was sufficient to increase lysine acetylation as assessed via immunoblot. Conclusion This study provided the first step in identifying multiple bioactive compound HDAC inhibitors. Taken together, this report sets the stage for future exploration of these bioactive compounds as epigenetic regulators to potentially ameliorate chronic disease. PMID:27981795

Design and implementation of an automated compound management system in support of lead optimization.

PubMed

Quintero, Catherine; Kariv, Ilona

2009-06-01

To meet the needs of the increasingly rapid and parallelized lead optimization process, a fully integrated local compound storage and liquid handling system was designed and implemented to automate the generation of assay-ready plates directly from newly submitted and cherry-picked compounds. A key feature of the system is the ability to create project- or assay-specific compound-handling methods, which provide flexibility for any combination of plate types, layouts, and plate bar-codes. Project-specific workflows can be created by linking methods for processing new and cherry-picked compounds and control additions to produce a complete compound set for both biological testing and local storage in one uninterrupted workflow. A flexible cherry-pick approach allows for multiple, user-defined strategies to select the most appropriate replicate of a compound for retesting. Examples of custom selection parameters include available volume, compound batch, and number of freeze/thaw cycles. This adaptable and integrated combination of software and hardware provides a basis for reducing cycle time, fully automating compound processing, and ultimately increasing the rate at which accurate, biologically relevant results can be produced for compounds of interest in the lead optimization process.

Process for preparing a chemical compound enriched in isotope content. [nitrogen 15-enriched nitric acid

DOEpatents

Michaels, E.D.

1981-02-25

A process to prepare a chemical enriched in isotope content includes: a chemical exchange reaction between a first and second compound which yields an isotopically enriched first compound and an isotopically depleted second compound; the removal of a portion of the first compound as product and the removal of a portion of the second compound as spent material; the conversion of the remainder of the first compound to the second compound for reflux at the product end of the chemical exchange reaction region; the conversion of the remainder of the second compound to the first compound for reflux at the spent material end of the chemical exchange region; and the cycling of the additional chemicals produced by one conversion reaction to the other conversion reaction, for consumption therein. One of the conversion reactions is an oxidation reaction, and the energy that it yields is used to drive the other conversion reaction, a reduction. The reduction reaction is carried out in a solid polymer electrolyte electrolytic reactor. The overall process is energy efficient and yields no waste by-products. A particular embodiment of the process in the production of nitrogen-15-enriched nitric acid.

DNA-encoded libraries - an efficient small molecule discovery technology for the biomedical sciences.

PubMed

Kunig, Verena; Potowski, Marco; Gohla, Anne; Brunschweiger, Andreas

2018-06-27

DNA-encoded compound libraries are a highly attractive technology for the discovery of small molecule protein ligands. These compound collections consist of small molecules covalently connected to individual DNA sequences carrying readable information about the compound structure. DNA-tagging allows for efficient synthesis, handling and interrogation of vast numbers of chemically synthesized, drug-like compounds. They are screened on proteins by an efficient, generic assay based on Darwinian principles of selection. To date, selection of DNA-encoded libraries allowed for the identification of numerous bioactive compounds. Some of these compounds uncovered hitherto unknown allosteric binding sites on target proteins; several compounds proved their value as chemical biology probes unraveling complex biology; and the first examples of clinical candidates that trace their ancestry to a DNA-encoded library were reported. Thus, DNA-encoded libraries proved their value for the biomedical sciences as a generic technology for the identification of bioactive drug-like molecules numerous times. However, large scale experiments showed that even the selection of billions of compounds failed to deliver bioactive compounds for the majority of proteins in an unbiased panel of target proteins. This raises the question of compound library design.

Targeting the epigenome: Screening bioactive compounds that regulate histone deacetylase activity.

PubMed

Godoy, Luis D; Lucas, Julianna E; Bender, Abigail J; Romanick, Samantha S; Ferguson, Bradley S

2017-04-01

Nutrigenomics is a rapidly expanding field that elucidates the link between diet-genome interactions. Recent evidence demonstrates that regulation of the epigenome, and in particular inhibition of histone deacetylases (HDACs), impact pathogenetic mechanisms involved in chronic disease. Few studies, to date, have screened libraries of bioactive compounds that act as epigenetic modifiers. This study screened a library of 131 natural compounds to determine bioactive compounds that inhibit Zn-dependent HDAC activity. Using class-specific HDAC substrates, we screened 131 natural compounds for HDAC activity in bovine cardiac tissue. From this screen, we identified 18 bioactive compound HDAC inhibitors. Using our class-specific HDAC substrates, we next screened these 18 bioactive compounds against recombinant HDAC proteins. Consistent with inhibition of HDAC activity, these compounds were capable of inhibiting activity of individual HDAC isoforms. Lastly, we report that treatment of H9c2 cardiac myoblasts with bioactive HDAC inhibitors was sufficient to increase lysine acetylation as assessed via immunoblot. This study provided the first step in identifying multiple bioactive compound HDAC inhibitors. Taken together, this report sets the stage for future exploration of these bioactive compounds as epigenetic regulators to potentially ameliorate chronic disease. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Energy gap formation mechanism through the interference phenomena of electrons in face-centered cubic elements and compounds with the emphasis on half-Heusler and Heusler compounds

NASA Astrophysics Data System (ADS)

Mizutani, U.; Sato, H.

2018-05-01

Many face-centred cubic elements and compounds with the number of atoms per unit cell N equal to 8, 12 and 16 are known to be stabilised by forming either a band gap or a pseudogap at the Fermi level. They are conveniently expressed as cF8, cF12 and cF16, respectively, in the Pearson symbol. From the cF8 family, we worked on three tetravalent elements C (diamond), Si and Ge, SZn-type AsGa compound and NaCl-type compounds like BiLu, AsSc, etc. From the cF12 family, more than 80 compounds were selected, with a particular emphasis on ABC- and half-Heusler-type ternary equiatomic compounds. Among cF16 compounds, both the Heusler compounds ABC2 and Zintl compounds were studied. We revealed that, regardless of whether or not the transition metal (TM) and/or rare-earth (RE) elements are involved as constituent elements, the energy gap formation mechanism for cF8, cF12 and cF16 compounds can be universally discussed in terms of interference phenomenon of itinerant electrons with set of reciprocal lattice planes with ? = 8, 11 and 12, where ? refers to square of the critical reciprocal of lattice vector of an fcc lattice. The number of itinerant electrons per unit cell, e/uc, for all these band gap/pseudogap-bearing compounds is found to fall on a universal line called "3/2-power law" when plotted against ? on a logarithmic scale. This proves the validity of the fulfilment of the interference condition ? in conformity with other pseudogap compounds with different crystal symmetries and different sizes of the unit cell reported in literature.

Influence of Various Phenolic Compounds on Properties of Gelatin Film Prepared from Horse Mackerel Trachurus japonicus Scales.

PubMed

Le, Thuy; Maki, Hiroki; Okazaki, Emiko; Osako, Kazufumi; Takahashi, Kigen

2018-06-15

Influence of various phenolic compounds on physical properties and antioxidant activity of gelatin film from horse mackerel Trachurus japonicus scales was investigated. Tensile strength (TS) of the film was enhanced whereas elongation at break was declined by adding 1% to 5% phenolic compounds. Rutin was the most effective to improve the TS compared to the other tested phenolic compounds including ferulic acid, caffeic acid, gallic acid, and catechin. Gelatin films with the phenolic compounds showed the excellent UV barrier properties. FTIR spectra exhibited that wavenumber of amide-A band of films decreased with formation of hydrogen bonding between amino groups of gelatin and hydroxyl groups of the phenolic compounds. Gelatin film incorporated with rutin which has the largest number of hydroxyl groups among the tested compounds demonstrated the lowest wavenumber for the amide-A peak. It is indicated that hydroxyl groups contained in the phenolic compounds contribute to formation of hydrogen bonds involved in improvement of the mechanical properties of the films. The incorporation of the phenolic compounds with gelatin films also led to the increasing of total phenolic contents and DPPH radical scavenging activities. Thus, it is concluded that phenolic compounds can promote the quality of gelatin film. Properties of gelatin film derived from horse mackerel scales can be improved by adding of phenolic compounds. Phenolic compounds containing a large number of hydroxyl groups should be selected to enhance physical properties of the gelatin film. A biodegradable film prepared from horse mackerel gelatin incorporated with phenolic compounds, which has good physical properties and antioxidant properties, can solve environmental problems caused by synthetic plastic materials. © 2018 Institute of Food Technologists®.

Update on medical and regulatory issues pertaining to compounded and FDA-approved drugs, including hormone therapy

PubMed Central

Pinkerton, JoAnn V.; Pickar, James H.

2016-01-01

Abstract Objective: We review the historical regulation of drug compounding, concerns about widespread use of non-Food and Drug Admiistration (FDA)-approved compounded bioidentical hormone therapies (CBHTs), which do not have proper labeling and warnings, and anticipated impact of the 2013 Drug Quality and Security Act (DQSA) on compounding. Methods: US government websites were searched for documents concerning drug compounding regulation and oversight from 1938 (passage of Federal Food, Drug, and Cosmetic Act [FDCA]) through 2014, including chronologies, Congressional testimony, FDA guidelines and enforcements, and reports. The FDCA and DQSA were reviewed. PubMed and Google were searched for articles on compounded drugs, including CBHT. Results: Congress explicitly granted the FDA limited oversight of compounded drugs in a 1997 amendment to the FDCA, but the FDA has encountered obstacles in exercising that authority. After 64 patient deaths and 750 adversely affected patients from the 2012 meningitis outbreak due to contaminated compounded steroid injections, Congress passed the DQSA, authorizing the FDA to create a voluntary registration for facilities that manufacture and distribute sterile compounded drugs in bulk and reinforcing FDCA regulations for traditional compounding. Given history and current environment, concerns remain about CBHT product regulation and their lack of safety and efficacy data. Conclusions: The DQSA and its reinforcement of §503A of the FDCA solidifies FDA authority to enforce FDCA provisions against compounders of CBHT. The new law may improve compliance and accreditation by the compounding industry; support state and FDA oversight; and prevent the distribution of misbranded, adulterated, or inconsistently compounded medications, and false and misleading claims, thus reducing public health risk. PMID:26418479

Host compounds for red phosphorescent OLEDs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xia, Chuanjun; Cheon, Kwang -Ohk

2015-08-25

Novel compounds containing a triphenylene moiety linked to an .alpha..beta. connected binaphthyl ring system are provided. These compounds have surprisingly good solubility in organic solvents and are useful as host compounds in red phosphorescent OLEDs.

Diazo compounds in the chemistry of fullerenes

NASA Astrophysics Data System (ADS)

Tuktarov, Airat R.; Dzhemilev, Usein M.

2010-09-01

Experimental and theoretical data on the reactions of different diazo compounds (diazomethane, its derivatives, cyclic diazo compounds and diazocarbonyl compounds) with fullerenes are summarized. The structures and stereochemistry of cycloadducts formed in these reactions are considered.

Method for purifying bidentate organophosphorus compounds

DOEpatents

Schulz, Wallace W.

1977-01-01

Bidentate organophosphorus compounds useful for extracting actinide elements from acidic nuclear waste solutions are purified of undesirable acidic impurities by contacting the compounds with ethylene glycol which preferentially extracts the impurities found in technical grade bidentate compounds.

Phytochemical investigation and hair growth studies on the rhizomes of Nardostachys jatamansi DC

PubMed Central

Gottumukkala, Venkateswara Rao; Annamalai, Tiruganasambandham; Mukhopadhyay, Triptikumar

2011-01-01

Nardostachys jatamansi DC rhizomes were subjected to extraction, fractionation, and isolation of terpenoid compounds. Three terpenoid compounds were isolated which are nardal, jatamansic acid, and nardin. These compounds were identified based on physical and spectral data (UV, IR,1H and13C NMR, 2D NMR, Mass) and comparison with authentic compounds. The crude extract, fractions, and two of the isolated compounds were tested for their hair growth activity. The hair growth studies showed good activities for the extract, fraction, and the isolated compounds. PMID:21716625

Rh-Catalyzed Intermolecular Reactions of α-Alkyl-α-Diazo Carbonyl Compounds with Selectivity over β-Hydride Migration

PubMed Central

DeAngelis, Andrew; Panish, Robert; Fox, Joseph M.

2016-01-01

CONSPECTUS Rh-carbenes derived from α-diazocarbonyl compounds have found broad utility across a remarkable range of reactivity, including cyclopropanation, cyclopropenation, C–H insertions, heteroatom–H insertions, and ylide forming reactions. However, in contrast to α-aryl or α-vinyl-α-diazocarbonyl compounds, the utility of α-alkyl-α-diazocarbonyl compounds had been moderated by the propensity of such compounds to undergo intramolecular β-hydride migration to give alkene products. Especially challenging had been intermolecular reactions involving α-alkyl-α-diazocarbonyl compounds. PMID:26689221

Heteroaromatic-based electrolytes for lithium and lithium-ion batteries

DOEpatents

Cheng, Gang; Abraham, Daniel P.

2017-04-18

The present invention provides an electrolyte for lithium and/or lithium-ion batteries comprising a lithium salt in a liquid carrier comprising heteroaromatic compound including a five-membered or six-membered heteroaromatic ring moiety selected from the group consisting of a furan, a pyrazine, a triazine, a pyrrole, and a thiophene, the heteroaromatic ring moiety bearing least one carboxylic ester or carboxylic anhydride substituent bound to at least one carbon atom of the heteroaromatic ring. Preferred heteroaromatic ring moieties include pyridine compounds, pyrazine compounds, pyrrole compounds, furan compounds, and thiophene compounds.

Cytotoxic constituents of ethyl acetate fraction from Dianthus superbus.

PubMed

Ding, Chengli; Zhang, Wu; Li, Jie; Lei, Jiachuan; Yu, Jianqing

2013-01-01

The ethyl acetate fraction (EE-DS) from Dianthus superbus was found to possess the cytotoxic activity against cancer cells in previous study. To investigate cytotoxic constituents, the bioassay-guided isolation of compounds from EE-DS was performed. Two dianthramides (1 and 2), three flavonoids (3-5), two coumarins (6 and 7) and three other compounds (8-10) were obtained. Structures of isolated compounds were identified by spectroscopic analysis. Cytotoxicity of the compounds against HepG2 cells was evaluated. Compound 1 showed the strongest cytotoxicity, compounds 10, 4, 3 and 5 had moderate cytotoxicity.

Study on real-time images compounded using spatial light modulator

NASA Astrophysics Data System (ADS)

Xu, Jin; Chen, Zhebo; Ni, Xuxiang; Lu, Zukang

2007-01-01

Image compounded technology is often used on film and its facture. In common, image compounded use image processing arithmetic, get useful object, details, background or some other things from the images firstly, then compounding all these information into one image. When using this method, the film system needs a powerful processor, for the process function is very complex, we get the compounded image for a few time delay. In this paper, we introduce a new method of image real-time compounded, use this method, we can do image composite at the same time with movie shot. The whole system is made up of two camera-lens, spatial light modulator array and image sensor. In system, the spatial light modulator could be liquid crystal display (LCD), liquid crystal on silicon (LCoS), thin film transistor liquid crystal display (TFTLCD), Deformable Micro-mirror Device (DMD), and so on. Firstly, one camera-lens images the object on the spatial light modulator's panel, we call this camera-lens as first image lens. Secondly, we output an image to the panel of spatial light modulator. Then, the image of the object and image that output by spatial light modulator will be spatial compounded on the panel of spatial light modulator. Thirdly, the other camera-lens images the compounded image to the image sensor, and we call this camera-lens as second image lens. After these three steps, we will gain the compound images by image sensor. For the spatial light modulator could output the image continuously, then the image will be compounding continuously too, and the compounding procedure is completed in real-time. When using this method to compounding image, if we will put real object into invented background, we can output the invented background scene on the spatial light modulator, and the real object will be imaged by first image lens. Then, we get the compounded images by image sensor in real time. The same way, if we will put real background to an invented object, we can output the invented object on the spatial light modulator and the real background will be imaged by first image lens. Then, we can also get the compounded images by image sensor real time. Commonly, most spatial light modulator only can do modulate light intensity, so we can only do compounding BW images if use only one panel which without color filter. If we will get colorful compounded image, we need use the system like three spatial light modulator panel projection. In the paper, the system's optical system framework we will give out. In all experiment, the spatial light modulator used liquid crystal on silicon (LCoS). At the end of the paper, some original pictures and compounded pictures will be given on it. Although the system has a few shortcomings, we can conclude that, using this system to compounding images has no delay to do mathematic compounding process, it is a really real time images compounding system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zeng, Xiaofei; Borole, Abhijeet P.; Pavlostathis, Spyros G.

Furanic and phenolic compounds are 20 lignocellulose-derived compounds known to inhibit to H2- and ethanol- producing microorganisms in dark fermentation. Bioelectrochemical conversion of furanic and phenolic compounds to electricity or H2 has recently been demonstrated as a productive method to use these compounds. However, potential inhibitory effect of furanic and phenolic compounds on exoelectrogenesis in bioelectrochemical systems is not well understood. This study systematically investigated the inhibitory effect of furfural (FF), 5-hydroxymethylfurfural (HMF), syringic acid (SA), vanillic acid (VA), and 4-hydroxybenzoic acid (HBA) on exoelectrogenesis in the bioanode of a microbial electrolysis cell. A mixture of these five compounds atmore » an increasing initial total concentration from 0.8 to 8.0 g/L resulted in current decrease up to 91%. The observed inhibition primarily affected exoelectrogenesis, instead of non-exoelectrogenic biotransformation pathways (e.g., fermentation) of the five compounds. Furthermore, the parent compounds at a high concentration, as opposed to their biotransformation products, were responsible for the observed inhibition. Tests with individual compounds show that all five parent compounds contributed to the observed inhibition by the mixture. The IC50 (concentration resulting in 50% current decrease) was estimated as 2.7 g/L for FF, 3.0 g/L for HMF, 1.9 g/L for SA, 2.1 g/L for VA and 2.0 g/L for HBA. Nevertheless, these compounds below their non-inhibitory concentrations jointly resulted in significant inhibition as a mixture. Catechol and phenol, which were persistent biotransformation products of the mixture, inhibited exoelectrogens at high concentrations, but to a lesser extent than the parent compounds. Recovery of exoelectrogenesis from inhibition by all compounds was observed, except for catechol, which resulted in irreversible inhibition. The reversibility of inhibition, as well as the observed difference in recovery rates, suggest different modes of exoelectrogenesis inhibition, related to the hydrophobicity of the inhibiting compounds.« less

Sterile compounding: clinical, legal, and regulatory implications for patient safety.

PubMed

Qureshi, Nabeel; Wesolowicz, Laurie; Stievater, Trish; Lin, Alexandra Tungol

2014-12-01

Poor compounding practices by the New England Compounding Center resulted in the 2012-2013 fungal infections outbreak. Contaminated injectable methylprednisolone led to the diagnosis of fungal infections in 751 patients and 64 deaths. In the United States, pharmacy compounding has traditionally been regulated by state boards of pharmacy rather than the FDA. To minimize safety risks related to pharmacy compounding, the Drug Quality and Security Act (DQSA) was signed into law November 27, 2013, to improve regulation of compounding pharmacies. To (a) review the literature regarding clinical, legal, and regulatory implications of pharmacy compounding for patient safety during the 2012-2013 fungal infections outbreak and (b) discuss strategies that managed care organizations (MCOs) can use to promote safe compounding practices.  A literature search was conducted via PubMed for original articles on fungal infections related to drug compounding published October 2012 to March 2014. Specific search terms included "drug compounding and fungal infection" and "fungal meningitis outbreak." The FDA website was also utilized for material related to the Food, Drug, and Cosmetic Act and the DQSA.  Four articles met inclusion criteria. The 2012-2013 fungal infections outbreak was attributed to 3 lots of preservative-free methylprednisolone acetate, which comprised 17,675 vials distributed to 76 facilities across 23 states. Median incubation period (from time of last injection to initial diagnosis) was 47 days, ranging from 0 to 249 days. According to the FDA, a total of 30 recalls regarding compounded products were issued by pharmacies during March through December 2013. Pharmacy compounding has the potential for significant safety risks. The purpose of the DQSA is to improve regulation of compounding pharmacies. Since registration as an outsourcing facility is voluntary, uncertainty still remains regarding advancement in safe compounding practices. MCOs can employ multiple strategies to ensure patient safety and promote appropriate drug therapy.

BioCompoundML: A General Biofuel Property Screening Tool for Biological Molecules Using Random Forest Classifiers

DOE PAGES

Whitmore, Leanne S.; Davis, Ryan W.; McCormick, Robert L.; ...

2016-09-15

Screening a large number of biologically derived molecules for potential fuel compounds without recourse to experimental testing is important in identifying understudied yet valuable molecules. Experimental testing, although a valuable standard for measuring fuel properties, has several major limitations, including the requirement of testably high quantities, considerable expense, and a large amount of time. This paper discusses the development of a general-purpose fuel property tool, using machine learning, whose outcome is to screen molecules for desirable fuel properties. BioCompoundML adopts a general methodology, requiring as input only a list of training compounds (with identifiers and measured values) and a listmore » of testing compounds (with identifiers). For the training data, BioCompoundML collects open data from the National Center for Biotechnology Information, incorporates user-provided features, imputes missing values, performs feature reduction, builds a classifier, and clusters compounds. BioCompoundML then collects data for the testing compounds, predicts class membership, and determines whether compounds are found in the range of variability of the training data set. We demonstrate this tool using three different fuel properties: research octane number (RON), threshold soot index (TSI), and melting point (MP). Here we provide measures of its success with these properties using randomized train/test measurements: average accuracy is 88% in RON, 85% in TSI, and 94% in MP; average precision is 88% in RON, 88% in TSI, and 95% in MP; and average recall is 88% in RON, 82% in TSI, and 97% in MP. The receiver operator characteristics (area under the curve) were estimated at 0.88 in RON, 0.86 in TSI, and 0.87 in MP. We also measured the success of BioCompoundML by sending 16 compounds for direct RON determination. Finally, we provide a screen of 1977 hydrocarbons/oxygenates within the 8696 compounds in MetaCyc, identifying compounds with high predictive strength for high or low RON.« less

Process for removing halogenated aliphatic and aromatic compounds from petroleum products

DOEpatents

Googin, J.M.; Napier, J.M.; Travaglini, M.A.

1983-09-20

A process is described for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced. 1 fig.

Studies of obtaining and stability in aqueous medium of new complex compounds of Ti(IV) and Zr(IV) used in ecological leather tanning

NASA Astrophysics Data System (ADS)

Crudu, Marian; Sibiescu, Doina; Rosca, Ioan; Sutiman, Daniel; Vizitiu, Mihaela

2009-01-01

In this paper, the study of obtaining new coordination compounds of Ti(IV) and Zr(IV) using as ligand: D,L-β-iso-butyric acid, is presented. Also, the stability of these compounds in aqueous medium is studied. The studies of obtaining and of stability of the new compounds were accomplished in aqueous solutions using methods characteristic for coordination compounds: conductance and pH measurements. The combination ratios and the stability were determined with methods characteristic for studies in solutions. From experimental data resulted that the combination ratio of central metallic atoms with the ligand derived from D,L-β-iso-butyric acid was 1:2. From experimental data resulted that in strong acid and strong basic mediums, the coordination compounds could not be obtained. The optimal stability of the studied compounds is limited between 3-6, pH - values. This fact is in accordance with the conditions of using these compounds in ecological leather tanning. Of great importance is that these compounds were used with very good results in tanning processes of different types of leather. This fact evidenced that the ecological alternative of tanning is better than non-ecological tanning using chrome compounds. The importance of this paper consists in obtaining new coordination compounds that can be used in ecological leather tanning.

Antifungal activity of schinol and a new biphenyl compound isolated from Schinus terebinthifolius against the pathogenic fungus Paracoccidioides brasiliensis

PubMed Central

2010-01-01

Background The aim of this study was to isolate and identify the antifungal compounds from the extracts of Schinus terebinthifolius (Anacardiaceae) against clinical isolates of the pathogenic fungus Paracoccidioides brasiliensis. Methods The hexane and dichlomethane fractions from leaves and stems of S. terebinthifolius were fractionated using several chromatography techniques to afford four compounds. Results The compounds isolated from S. terebinthifolius were identified as schinol (1), a new biphenyl compound, namely, 4'-ethyl-4-methyl-2,2',6,6'-tetrahydroxy[1,1'-biphenyl]-4,4'-dicarboxylate (2), quercetin (3), and kaempferol (4). Compounds 1 and 2 were active against different strains of P. brasiliensis, showing a minimal inhibitory concentration value against the isolate Pb B339 of 15.6 μg/ml. The isolate Pb 1578 was more sensitive to compound 1 with a MIC value of 7.5 μg/ml. Schinol presented synergistic effect only when combined with itraconazole. The compounds isolated from S. terebinthifolius were not able to inhibit cell wall synthesis or assembly using the sorbitol assay. Conclusion This work reveals for the first time the occurrence of compound 2 and discloses activity of compounds 1 and 2 against several clinical isolates of P. brasiliensis. These results justify further studies to clarify the mechanisms of action of these compounds. PMID:20939907

Preparation and antibacterial activity of compound chitosan-compound Yizhihao-nanoparticles.

PubMed

Ou, Sheng; Zhang, Yang-de

2008-05-01

To prepare chitosan (CS)-compound Yizhihao-nanoparticles (NP) and to investigate its antibacterial activity. CS NPs were formed by the incorporation of CS and Na3 PO4. CS-compound Yizhihao NPs were prepared by ion-cross-linking. The particle sizes and surface charges of CS NPs were determined by Malvern Zetasizer 1000-HAS and atomic force microscope (AFM), respectively. The antibacterial activity of CS-compound Yizhihao-NPs was studied in vitro and compared with that of compound Yizhihao powder. Malvern Zetasizer 1000-HAS and AFM demonstrated that the diameter of CS-compound Yizhihao NPs was (137.00+/-14.28)nm and CS NPs had (16.90+/-1.32)mV positive surface charges. The minimal inhibitory concentrations (MIC) of CS-compound Yizhihao NPs on Staphylococcus aureus,Pneumococcus,beta-hemolytic streptococcus, and Escherichia coli were 1:32,1:32,1:16,and 1:2, respectively. The minimal bactericidal concentrations (MBC) of CS-compound Yizhihao-NPs on Staphylococcus aureus, Pneumococcus, beta-hemolytic streptococcus, and Escherichia coli were 1:16,1:16,1:8, and 1:2, respectively. The antibacterial efficacy of CS-compound Yizhihao-NPs to Staphylococcus aureus, Pneumococcus, and beta-hemolytic streptococcus had been improved significantly (P< 0.05). CS-compound Yizhihao-nanoparticles have obvious antibacterial activity to the Staphylococcus aureus,Pneumococcus,and beta-hemolytic streptococcus,which lays the experimental foundation for new preparation of traditional Chinese medicine in future research.

Process for removing halogenated aliphatic and aromatic compounds from petroleum products

DOEpatents

Googin, John M.; Napier, John M.; Travaglini, Michael A.

1983-01-01

A process for removing halogenated aliphatic and aromatic compounds, e.g., polychlorinated biphenyls, from petroleum products by solvent extraction. The halogenated aliphatic and aromatic compounds are extracted from a petroleum product into a polar solvent by contacting the petroleum product with the polar solvent. The polar solvent is characterized by a high solubility for the extracted halogenated aliphatic and aromatic compounds, a low solubility for the petroleum product and considerable solvent power for polyhydroxy compound. The preferred polar solvent is dimethylformamide. A miscible compound, such as, water or a polyhydroxy compound, is added to the polar extraction solvent to increase the polarity of the polar extraction solvent. The halogenated aliphatic and aromatic compounds are extracted from the highly-polarized mixture of water or polyhydroxy compound and polar extraction solvent into a low polar or nonpolar solvent by contacting the water or polyhydroxy compound-polar solvent mixture with the low polar or nonpolar solvent. The halogenated aliphatic and aromatic compounds and the low polar or nonpolar solvent are separated by physical means, e.g., vacuum evaporation. The polar and nonpolar solvents are recovered from recycling. The process can easily be designed for continuous operation. Advantages of the process include that the polar solvent and a major portion of the nonpolar solvent can be recycled, the petroleum products are reclaimable and the cost for disposing of waste containing polychlorinated biphenyls is significantly reduced.

LigandBox: A database for 3D structures of chemical compounds

PubMed Central

Kawabata, Takeshi; Sugihara, Yusuke; Fukunishi, Yoshifumi; Nakamura, Haruki

2013-01-01

A database for the 3D structures of available compounds is essential for the virtual screening by molecular docking. We have developed the LigandBox database (http://ligandbox.protein.osaka-u.ac.jp/ligandbox/) containing four million available compounds, collected from the catalogues of 37 commercial suppliers, and approved drugs and biochemical compounds taken from KEGG_DRUG, KEGG_COMPOUND and PDB databases. Each chemical compound in the database has several 3D conformers with hydrogen atoms and atomic charges, which are ready to be docked into receptors using docking programs. The 3D conformations were generated using our molecular simulation program package, myPresto. Various physical properties, such as aqueous solubility (LogS) and carcinogenicity have also been calculated to characterize the ADME-Tox properties of the compounds. The Web database provides two services for compound searches: a property/chemical ID search and a chemical structure search. The chemical structure search is performed by a descriptor search and a maximum common substructure (MCS) search combination, using our program kcombu. By specifying a query chemical structure, users can find similar compounds among the millions of compounds in the database within a few minutes. Our database is expected to assist a wide range of researchers, in the fields of medical science, chemical biology, and biochemistry, who are seeking to discover active chemical compounds by the virtual screening. PMID:27493549

LigandBox: A database for 3D structures of chemical compounds.

PubMed

Kawabata, Takeshi; Sugihara, Yusuke; Fukunishi, Yoshifumi; Nakamura, Haruki

2013-01-01

A database for the 3D structures of available compounds is essential for the virtual screening by molecular docking. We have developed the LigandBox database (http://ligandbox.protein.osaka-u.ac.jp/ligandbox/) containing four million available compounds, collected from the catalogues of 37 commercial suppliers, and approved drugs and biochemical compounds taken from KEGG_DRUG, KEGG_COMPOUND and PDB databases. Each chemical compound in the database has several 3D conformers with hydrogen atoms and atomic charges, which are ready to be docked into receptors using docking programs. The 3D conformations were generated using our molecular simulation program package, myPresto. Various physical properties, such as aqueous solubility (LogS) and carcinogenicity have also been calculated to characterize the ADME-Tox properties of the compounds. The Web database provides two services for compound searches: a property/chemical ID search and a chemical structure search. The chemical structure search is performed by a descriptor search and a maximum common substructure (MCS) search combination, using our program kcombu. By specifying a query chemical structure, users can find similar compounds among the millions of compounds in the database within a few minutes. Our database is expected to assist a wide range of researchers, in the fields of medical science, chemical biology, and biochemistry, who are seeking to discover active chemical compounds by the virtual screening.

Molecular diversity management strategies for building and enhancement of diverse and focused lead discovery compound screening collections.

PubMed

Schuffenhauer, A; Popov, M; Schopfer, U; Acklin, P; Stanek, J; Jacoby, E

2004-12-01

This publication describes processes for the selection of chemical compounds for the building of a high-throughput screening (HTS) collection for drug discovery, using the currently implemented process in the Discovery Technologies Unit of the Novartis Institute for Biomedical Research, Basel Switzerland as reference. More generally, the currently existing compound acquisition models and practices are discussed. Our informatics, chemistry and biology-driven compound selection consists of two steps: 1) The individual compounds are filtered and grouped into three priority classes on the basis of their individual structural properties. Substructure filters are used to eliminate or penalize compounds based on unwanted structural properties. The similarity of the structures to reference ligands of the main proven druggable target families is computed, and drug-similar compounds are prioritized for the following diversity analysis. 2) The compounds are compared to the archive compounds and a diversity analysis is performed. This is done separately for the prioritized, regular and penalized compounds with increasingly stringent dissimilarity criterion. The process includes collecting vendor catalogues and monitoring the availability of samples together with the selection and purchase decision points. The development of a corporate vendor catalogue database is described. In addition to the selection methods on a per single molecule basis, selection criteria for scaffold and combinatorial chemistry projects in collaboration with compound vendors are discussed.

Thin films of mixed metal compounds

DOEpatents

Mickelsen, R.A.; Chen, W.S.

1985-06-11

Disclosed is a thin film heterojunction solar cell, said heterojunction comprising a p-type I-III-IV[sub 2] chalcopyrite substrate and an overlying layer of an n-type ternary mixed metal compound wherein said ternary mixed metal compound is applied to said substrate by introducing the vapor of a first metal compound to a vessel containing said substrate from a first vapor source while simultaneously introducing a vapor of a second metal compound from a second vapor source of said vessel, said first and second metals comprising the metal components of said mixed metal compound; independently controlling the vaporization rate of said first and second vapor sources; reducing the mean free path between vapor particles in said vessel, said gas being present in an amount sufficient to induce homogeneity of said vapor mixture; and depositing said mixed metal compound on said substrate in the form of a uniform composition polycrystalline mixed metal compound. 5 figs.

Volatile composition of some Brazilian fruits: umbu-caja (Spondias citherea), camu-camu (Myrciaria dubia), Araça-boi (Eugenia stipitata), and Cupuaçu (Theobroma grandiflorum).

PubMed

Franco, M R; Shibamoto, T

2000-04-01

Twenty-one volatile compounds were identified for the first time by GC-MS in umbu-caja and in camu-camu, plus 30 volatile compounds were identified in araça-boi samples. Terpenic compounds predominated among the volatile compounds in these fruit samples, with the major compounds being identified as cis-beta-ocimene and caryophyllene in the northeastern fruit; alpha-pinene and d-limonene were the most abundant volatile compounds in the headspace of the Amazonian fruit camu-camu. Sesquiterpenes were the most abundant compounds in the araça-boi sample, with germacrene D presenting a higher relative percentage. The chemical class of esters predominated in the cupuaçu sample. Ethyl butyrate and hexanoate were the major compounds in the headspace of this Amazonian fruit.

NEW RENIN INHIBITORS - STABILITY AND ACTIVITY DETERMINATION. PART IV.

PubMed

Marszalek, Dorota; Goldnik, Anna; Winiecka, Iwona; Jaworsk, Pawel; Mazurek Aleksander P

2017-03-01

A series of new seven potential renin inhibitors containing pseudodipeptides were synthesized. Stability for all compounds (1-7) in homogenates of liver, kidney, lung and in serum, gastric, intestinal juice and in the presence of α-chymotrypsin was determined. Compound 1 was unstable in all determined mediums. Compounds 2, 4, 5 and 7 were unstable, compound 3 was stable, compound 6 was unstable only in α-chy-motrypsin solution. Inhibitory activity of the compounds was measured in vitro by HPLC determination of low-ering concentration of substrate (angiotensinogen) in the presence of renin and the potential renin inhibitor (compounds 1-7). Compounds 1, 2, 4, 5, 6 and 7 showed inhibitory activity (1.12 x 10⁻⁷, 0.96 x 10⁻⁶, 1.58 x10⁻⁷,1.68 x 10⁻⁶, 1.30 x 10⁻⁶, 0.96 x 10⁻⁷M, respectively).

Characterization of aroma compounds in apple cider using solvent-assisted flavor evaporation and headspace solid-phase microextraction.

PubMed

Xu, Yan; Fan, Wenlai; Qian, Michael C

2007-04-18

The aroma-active compounds in two apple ciders were identified using gas chromatography-olfactometry (GC-O) and GC-mass spectrometry (MS) techniques. The volatile compounds were extracted using solvent-assisted flavor evaporation (SAFE) and headspace solid-phase microextraction (HS-SPME). On the basis of odor intensity, the most important aroma compounds in the two apple cider samples were 2-phenylethanol, butanoic acid, octanoic acid, 2-methylbutanoic acid, 2-phenylethyl acetate, ethyl 2-methylbutanoate, ethyl butanoate, ethyl hexanoate, 4-ethylguaiacol, eugenol, and 4-vinylphenol. Sulfur-containing compounds, terpene derivatives, and lactones were also detected in ciders. Although most of the aroma compounds were common in both ciders, the aroma intensities were different. Comparison of extraction techniques showed that the SAFE technique had a higher recovery for acids and hydroxy-containing compounds, whereas the HS-SPME technique had a higher recovery for esters and highly volatile compounds.