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In this research, TGA technique was used for determining thermal and gravimetrical stability of Al/Sn/La2O3 nanostructures prepared by sol-gel and spin-coating methods. Structural properties and surface morphology of the films were investigated by different analysis methods. Energy dispersive X-ray spectroscopy and a map were used to make a quantitative chemical analysis of unknown materials. Electrical properties of the samples were measured by metal-dielectric-semiconductor through capacitance–voltage and current rate–voltage. The conduction mechanism in the electrical field below 0.12 MV/cm and in the temperature range of 335 K < T < 420 K was found to be ohmic emission. A model of thermal excitation is proposed to explain the mechanism of ohmic conduction current. The highest value of dielectric constant (k) was ~32 at T1 = 200°C with almost amorphous structure. The results showed that at T1 = 200°C the Al/Sn/La2O3 nanostructure has lower leakage current rate and higher capacitance than those for other samples because of almost amorphous structure. [ABSTRACT FROM AUTHOR]

This paper reports tests on a lab-scale surface aeration vessel was equipped with a Rushton turbine to examine its performance in terms of standard aeration efficiency (SAE), mixing time, and void fraction characteristics. These characteristics were investigated by tests using variations of rotor speed, impeller immersion depth, and water level. Results showed that variation of impeller immersion depth had a greater effect on the SAE compared to variation of water level. More over, the SAE increased with rotor speeds up to about 150 to 200 rpm and then decreased. In addition, void fraction improved by impeller immersion depth and rotor speed enhancement; however, mixing time and power number were reduced as rotor speed increased. According to the response surface methodology statistical optimizations, optimum values for rotor speed, impeller immersion depth, and water level were 168.90 rpm, 25 mm, and 30 cm, respectively, to achieve the maximum value of SAE. [ABSTRACT FROM AUTHOR]

More treatment is needed for sulfur recovery unit tail gas, due to its high pollution. In this research, an Iranian petroleum refinery was selected as a case study. In the proposed refinery, incineration is used for treatment of tail gas. As incineration is not an environment-friendly process, an amine-based process has been selected as the best method for treatment of tail gas. The selected process was simulated with HYSYS and Aspen-Plus software. Different parameters and their changes were investigated through the simulation and optimum conditions were achieved. Also, comparison of results of two simulation softwares was done. [ABSTRACT FROM PUBLISHER]

Lythrum salicaria L. (Lythraceae) known as purple loosestrife used for its beneficial health effects against as many human diseases such as diarrhea, hemorrhoid, eczema internally and/ or externally. The effects of the different extracting methods on the total phenolic (TP) and total flavonoid (TF) contents of Lythrum salicaria L. extracts were investigated. Dried leaf and flower of L. salicaria were extracted with three different methods (percolation method, ultrasonic assisted extraction and polyphenol fraction). The antioxidant activities of extracts were investigated by different methods, i.e. 1,1-diphenyl-2-picryl hydrazyl radical (DPPH), nitric oxide and hydrogen peroxide scavenging activities as well as reducing power using standard methods. Phenol and flavonoid contents were also determined as gallic acid and quercetin equivalents, respectively. Extracts exhibited good antioxidant activity in all test models. In general, flower showed better activity than leaf extracts. Ultrasonic extract of flower showed the best activity in scavenging of hydrogen peroxide but polyphenol fraction was the more potent one in other tests. Its higher phenolic and flavonoid contents could be responsible for its antioxidant activity. [ABSTRACT FROM AUTHOR]

Background: Corn silk is obtained from the plant Zea mays L. A traditional herbal medicine is in China. This has been used in many parts of the world to treat edema, kidney infections, gout, kidney stones, kidney diseases and prostate. Reports of the antioxidant effects of this material are available. Although little scientific resources are available to confirm its efficacy. In this study we tried to find out the antioxidant effect and preventing of hepatotoxicity effect of Corn silk with IRLP Isolated Rat Liver Perfusion) system. Material and Methods: The aqueous and methanol extracts of dried Corn silk doses (10, 20, 40, 50 and 100 mg/kg) was used. Albino Rats weighing 220-180 g were examined after anesthesia by diethyl ether, the abdominal cavity of the animal T-shaped pattern excision in the abdomen and around) is opened. Then portal vein connected to the perfusion flow by using small scalp Vienna (No. 23) into the portal vein. After reaching perfusion flow rate to 20 ml per minute, extracts and fraction with above doses were added to perfusion buffer. Fluid outflows from the inferior vena cava, were collected for measurement of glutathione. One sample of the liver was removed for glutathione measurement and one sample was maintained in 10% formalin for histopathological examination. Differences between group means were estimated using oneway ANOVA followed by Duncan's multiple range test. Results: The results showed that reduced glutathione level increased significantly by aqueous and methanol extract in comparison with controls. Pathology results confirmed that by increasing dose of extracts, severity of tissue damage (hemorrhage, fibrosis, and necrosis) is reduced. In samples taken at intervals of 120 minutes, changes in the glutathione of case groups showed significant difference in comparison with the control group (p<0.01). Conclusion: Findings indicated that aqueous and methanolic extracts of corn fiber, reduced hepatic damages of MDMA significantly. This effect was dose dependent and because of flavonoid and phenol compounds. [ABSTRACT FROM AUTHOR]

Joint destruction in early adulthood brings the patients to the orthopaedic clinics. If a haemophilic patient becomes disabled, it shows a number of factors such as timely diagnosis, availability of appropriate treatment depending on the country, access and affordability to treatments and equally importantly the responsibility of the patient in managing self care by remaining compliant by prescribed treatment regimen. We assessed the functional level by functional independence score in haemophilia ( FISH). Overall, 104 patients with haemophilia A and 29 with haemophilia B were evaluated. We assessed the function of the patients by FISH. We divided the sum scores into weak ( FISH score 8-16), moderate (17-24), and good (25-32). For evaluating the level of functional deficit in a 2 × 2 table, we categorized the weak and moderate levels into Disordered Group and the good level into Not-Disordered Group. The average age was 26.9 ± 14.24. Each 1 year increase in age can increase 1.07 fold the possibility of being placed in Disordered Function Group. Severe haemophilia can increase 7.34 fold, presence of inhibitor can increase 9.75 fold and home self-care increases 3.89 fold the possibility of being placed in Disordered Function Group. To decrease the burden of the cost on patient, family and the government, education plays the most important role. We suggest that we send a trained team of physician and nurses to the deprived villages and cities instead of waiting for the patient to refer to our Care Center. [ABSTRACT FROM AUTHOR]

Hypericum perforatum is used as a folk remedy for the treatment of various neurological disorders. In this study, antioxidant activity of flower-bearing branches of H. perforatum was investigated employing various in vitro assay systems. IC50 for DPPH radical-scavenging activity was 96.0 ± 3.7 µg ml-1. Extract showed potent nitric oxide scavenging activity between 6.25 and 100 µg ml-1. Percentage of inhibition was increased with increasing concentrations of the extract. IC50 was 21.1±1.8 µg ml-1. Extract showed good reducing power that was comparable with vitamin C (p> 0.05). Extract showed very weak Fe2+ chelating ability. Percentage of inhibition was 41% at 200 µg ml-1 in scavenging of H2O2. This plant was a good source of phenols and contains very high amount of total phenolics. Total phenol compounds, as determined by the Folin Ciocalteu method, was 505.7 ± 18 mg GAE and the total flavonoid content, by AlCl3 method was 23.8 ± 1.6 mg QE. Antioxidant activity may be attributed, at least in part, to the presence of high amount of phenols and flavonoids in the extract. Potent nitric oxide scavenging activity may explain reported anti-inflammatory and CNS activities of this plant. These activities may be partially mediated by NO pathway. [ABSTRACT FROM AUTHOR]

Background and Objective: Legg-Calve-Perthes disease is one of the most common disabling diseases of childhood and if not managed appropriately is truly disabling. Severity of disease and duration of disease onset are main determinants of choosing treatment strategy of either conservative management or surgical treatment. This study was designed to determine Legg- Calve-Perthes treatments and relation between type of treatment and duration of the disease. Materials and Methods: This descriptive study was carreid out on 50 patients with Legg-Calve- Perthes disease admitted in Ghaem Hospital in Mashhad, North East of Iran from 1995-2005. Results: According to age of patients and severity of disease, the subjects allocated to conservatine (11 patients) and surgical treatment (39 patients). Clinical improvment signs include pain reduction, range of joints motion, which were avaluate by physical examination and taking medical history of patients. In conservative group, only 4 patients assumed to be successfully treated with mean age of 7.25 years and the mean interval between disease onset and beginning of treatment was 2.25 months. Surgical group had mean age of 10.85 years and mean interval between onset of disease and initiation of treatment was 18 months. Conservative group showed less sever form of disease (lateral pillar group A and group B with age less than 8 years), but patients treated surgically were more severely involved (lateral pillar group B with age more than 8 years and group C). Conclusion: This study showed that age and severity of disease (lateral pillar classification) are main elements in treatment strategy (choosing conservative VS surgical treatment). The interval between onset of disease and onset of treatment strongly affects treatment success. [ABSTRACT FROM AUTHOR]

We report 80 GHz of mode-hop-free tuning from an extended cavity diode laser (ECDL) without the need for antireflection coating on the diode facet. A large continuous tuning range was achieved by using a simple electronic circuit which simultaneously varies the diode laser current and external cavity length in an appropriate ratio. The ECDL employs a commercial, single mode AlGaAs diode laser, operating at 814 nm, in a Littrow external cavity configuration. The applicability of this technique to the most commonly available single-mode diode lasers without the requirement of antireflection coating, makes it an attractive approach for the attainment of mode-hop-free tuning over extended ranges. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract. We report the generation of tunable high-repetition-rate optical pulses in the mid-infrared using synchronously pumped parametric oscillation in periodically poled LiNbO[sub 3] (PPLN). Using a Kerr-lens-mode-locked Ti:sapphire laser as the pump source and a PPLN crystal incorporating grating periods of 21.0-22.4 micro m, we have achieved wavelength conversion in the 4-6-micro m spectral range in the mid-infrared. The use of a semi-monolithic cavity design and hemispherical focusing has permitted pulse generation in the strong idler absorption region of PPLN, resulting in a simple, compact, all-solid-state configuration with a pump power threshold as low as 17 mW and mid-infrared idler powers of up to 64 mW at 9% extraction efficiency. Signal output powers of up to 280 mW at 35% extraction efficiency am available over the 1.004-1.140-micro m spectral range at 80.5 MHz and pulse repetition rates at harmonics of the fundamental frequency up to 322 MHz have also been obtained. [ABSTRACT FROM AUTHOR]

Abstract. We describe a synchronously pumped optical parametric oscillator based on periodically poled RbTiOAsO[sub 4] that is continuously tunable in the signal wavelength from 1.375 to 1.575 micro m and with a maximum output power of 110 mW. The signal pulses were produced with nearly transform-limited duration as short as 215 fs. [ABSTRACT FROM AUTHOR]

Abstract. We describe the steady-state and transient power characteristics of continuous-wave intracavity singly resonant parametric oscillators (ICSROs). The operation characteristics of recently demonstrated ICSROs are reviewed. We derive a rate-equation model for the ICSRO which features a multi-frequency laser field. The steady-state behaviour of the device is detailed and methods to optimise the signal and idler outputs are presented. A Liapunov analysis tests the high-power stability of the system. We find that ICSROs do not suffer from the problems of instability which are characteristic of other intracavity frequency-mixing schemes and, as such, represent practical continuous-wave sources capable of high output powers and conversion efficiencies. Finally, we quantify the level of practical stability through an analysis of the novel transient behaviour of the ICSRO. We find that, to optimise the power stability, the signal cavity lifetime should be made as large as possible. [ABSTRACT FROM AUTHOR]

The design, configuration and operation of Ti:Sapphire-laser-pumped femtosecond Optical Parametric Oscillators (OPOs) using KTP and RTA are described. The results presented include configurations capable of producing transform-limited pulses shorter than 40 fs and operating with pump powers as low as 50 mW. Tunability within the 1-3 µn spectral region is demonstrated using pump-tuning alone. [ABSTRACT FROM AUTHOR]

We report a new source of high-repetition rate and widely tunable picosecond pulses for the near infrared. A singly resonant, cw, picosecond optical parametric oscillator based on temperature-tuned LiBO and synchronously pumped by 1.8 ps pulses from a self-mode-locked Ti:Sapphire laser is demonstrated. The oscillator can provide average output powers of up to 90 mW under non-critical type-I phase matching at a pulse repetition rate of 81 MHz. Without dispersion compensation, transform-limited signal pulses with 720 fs durations have been generated at 1.2 times threshold. With the available mirror set, signal tuning over 1.374-1.530 µm and idler tuning over 1.676-1.828 µm is demonstrated for a range of pump wavelengths and phase-matching temperatures. With additional mirrors, continuous tuning throughout 1-2.7 µm should be readily attainable with a single LiBO crystal. [ABSTRACT FROM AUTHOR]

The operation and characterization of a high-repetition-rate singly-resonant picosecond optical parametric oscillator based on the non-linear material KTiOAsO4 and synchronously pumped by a Kerr-lens-mode-locked Ti:sapphire laser at 81 MHz is described. By utilizing non-critical type II phase-matching in a 10 mm crystal, average near-infrared output powers of 403 mW have been generated at 31% extraction efficiency. The oscillator exhibits a pump power threshold of 230 mW and with the available mirror set can provide signal tuning over 1.116–1.281 μm and idler tuning over 2.260–3.160 μm by tuning the pump wavelength over 770–896 nm. Without dispersion compensation, near-transform-limited signal pulses with durations of 1.01–1.03 ps and idler pulses with 1.61–2.91 ps duration have been obtained for 1.2 ps input pump pulses. [ABSTRACT FROM AUTHOR]

Using natural compounds such as flavonoids in combination therapy methods in various diseases such as atopic dermatitis and psoriasis are under special consideration. Unfortunately poor solubility of flavonoids is a significant limitation in preparing pharmaceutical dosage forms. It is reported that preparing nanoparticles can overcome poor solubility problem of the compounds. The oil/water nanodispersions are a group of preparations in which the poorly soluble drugs could be dissolved in the oil core and/or adsorbed on the O/W interface. In this study, dispersion of flavonoids, quercetin (QC), and ferulic acid (FA) was prepared by solvent diffusion method in organic phase and lecithin. After adding the dispersion to the aqueous phase, ultrasonication and ultracentrifugation were carried out. A mixture of emulsifier and water were added and the mixture was ultrasonicated again. Solvent was removed under reduced pressure at 50 °C using nitrogen-purged vials. The particles were evaluated for size and size distribution, zeta potential (ZEN 3000, Malvern, England), shape, percent entrapment, and in vitro release. Differential scanning calorimetry method was used to understand the thermotropic properties and phase transition behavior. Droplet size of nanoparticles of QC and FA was 298±14 and 289±14 nm, respectively. The scanning electron microscope results show that the particles were spherical and majority of them were unilamellar. [ABSTRACT FROM AUTHOR]

We report optical second-harmonic generation (SHG) through modal phase matching in GaAs/ AlGaAs semiconductor waveguides. Using femtosecond pulses, both type-I and type-II SHG is demonstrated for fundamental wavelengths near 1.55 µm. [ABSTRACT FROM AUTHOR]

A continuous-wave pump-enhanced singly resonant optical parametric oscillator (OPO) directly pumped by a grating-stabilized external-cavity diode laser operating at approx. 810 nm is described. The OPO was based on periodically poled LiNbO[sub 3] and could be tuned over 1.06-1.19 μm at the signal and 2.58-3.44 μm at the idler. The OPO threshold was typically 25-30 mW over the observed tuning range. Up to 4 mW of one-directional idler output was obtained for 62 mW of external-cavity diode laser pump power. The high stability of the external-cavity diode-laser pump source allowed locked, single-mode OPO operation for periods of greater than 1 h. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract. We report difference frequency generation and temperature-tuned phase-matching in the nonlinear optical material periodically poled KTiOPO[sub 4] (PPKTP). We generated 12 mu W of radiation tunable around 1.6 mu m by difference-frequency mixing of the outputs of a frequency-doubled Nd:YLF laser at 523 nm (240 mW) and a tunable Ti:sapphire laser near 760 nm (340 mW). A temperature tuning rate of 0.73 nm/Celsius for the generated wavelength and a FWHM temperature acceptance bandwidth of 6.9 Celsius cm was observed. The effective d[sub 33] coefficient was estimated to be Is similar to 5 pm/V. [ABSTRACT FROM AUTHOR]

Demonstrates continuous-wave (cw) optical parametric oscillator (OPO). Use of lithium triborate as a nonlinear material; Application of cw OPO to generate nonclassical states of lights; Use of OPO for multichannel coherent optical communication system.

Demonstrates efficient operation of a broadly tunable picosecond optical parametric oscillator pumped by a diode-laser-pumped solid-state-laser. Characterization of nonlinear crystal LiB[sub 3]O[sub 5]; Possession of noncritical phase-matching capability and temperature tunability; Determination of the tuning range and spectral characteristics using a monochromator.