Science.gov

Sample records for level microwave irradiation

  1. Low-level microwave irradiation and central cholinergic systems

    SciTech Connect

    Lai, H.; Carino, M.A.; Horita, A.; Guy, A.W. )

    1989-05-01

    Our previous research showed that 45 min of exposure to low-level, pulsed microwaves (2450-MHz, 2-microseconds pulses, 500 pps, whole-body average specific absorption rate 0.6 W/kg) decreased sodium-dependent high-affinity choline uptake in the frontal cortex and hippocampus of the rat. The effects of microwaves on central cholinergic systems were further investigated in this study. Increases in choline uptake activity in the frontal cortex, hippocampus, and hypothalamus were observed after 20 min of acute microwave exposure, and tolerance to the effect of microwaves developed in the hypothalamus, but not in the frontal cortex and hippocampus, of rats subjected to ten daily 20-min exposure sessions. Furthermore, the effects of acute microwave irradiation on central choline uptake could be blocked by pretreating the animals before exposure with the narcotic antagonist naltrexone. In another series of experiments, rats were exposed to microwaves in ten daily sessions of either 20 or 45 min, and muscarinic cholinergic receptors in different regions of the brain were studied by 3H-QNB binding assay. Decreases in concentration of receptors occurred in the frontal cortex and hippocampus of rats subjected to ten 20-min microwave exposure sessions, whereas increase in receptor concentration occurred in the hippocampus of animals exposed to ten 45-min sessions. This study also investigated the effects of microwave exposure on learning in the radial-arm maze. Rats were trained in the maze to obtain food reinforcements immediately after 20 or 45 min of microwave exposure.

  2. Psychoactive-drug response is affected by acute low-level microwave irradiation

    SciTech Connect

    Lai, H.; Horita, A.; Chou, C.K.; Guy, A.W.

    1983-01-01

    The effects of various psychoactive drugs were studied in rats exposed for 45 min in a circularly polarized, pulsed microwave field (2450 MHz; SAR 0.6 W/kg; 2-microseconds pulses, 500 pps). Apomorphine-induced hypothermia and stereotypy were enhanced by irradiation. Amphetamine-induced hyperthermia was attenuated while stereotypy was unaffected. Morphine-induced catalepsy and lethality were enhanced by irradiation at certain dosages of the drug. Since these drugs have different modes of action on central neural mechanisms and the effects of microwaves depend on the particular drug studied, these results show the complex nature of the effect of microwave irradiation on brain functions.

  3. Acute low-level microwave exposure and central cholinergic activity: studies on irradiation parameters

    SciTech Connect

    Lai, H.; Horita, A.; Guy, A.W.

    1988-01-01

    Sodium-dependent high-affinity choline uptake was measured in the striatum, frontal cortex, hippocampus, and hypothalamus of rats after acute exposure (45 min) to pulsed (2 microseconds, 500 pps) or continuous-wave 2,450-MHz microwaves in cylindrical waveguides or miniature anechoic chambers. In all exposure conditions, the average whole-body specific absorption rate was at 0.6 W/kg. Decrease in choline uptake was observed in the frontal cortex after microwave exposure in all of the above irradiation conditions. Regardless of the exposure system used, hippocampal choline uptake was decreased after exposure to pulsed but not continuous-wave microwaves. Striatal choline uptake was decreased after exposure to either pulsed or continuous-wave microwaves in the miniature anechoic chamber. No significant change in hypothalamic choline uptake was observed under any of the exposure conditions studied. We conclude that depending on the parameters of the radiation, microwaves can elicit specific and generalized biological effects.

  4. Low-level microwave irradiation and central cholinergic activity: a dose-response study

    SciTech Connect

    Lai, H.; Carino, M.A.; Horita, A.; Guy, A.W.

    1989-01-01

    Rats were irradiated with circularly polarized, 2,450-MHz pulsed microwaves (2-microseconds pulses, 500 pulses per second (pps)) for 45 min in the cylindrical waveguide system of Guy et al. Immediately after exposure, sodium-dependent high-affinity choline uptake, an indicator of cholinergic activity in neural tissue, was measured in the striatum, frontal cortex, hippocampus, and hypothalamus. The power density was set to give average whole-body specific absorption rates (SAR) of 0.3, 0.45, 0.6, 0.75, 0.9, or 1.2 W/kg to study the dose-response relationship between the rate of microwave energy absorption and cholinergic activity in the different areas of the brain. Decrease in choline uptake was observed in the striatum at a SAR of 0.75 W/kg and above, whereas for the frontal cortex and hippocampus, decreases in choline uptake were observed at a SAR of 0.45 W/kg and above. No significant effect was observed in the hypothalamus at the irradiation power densities studied. The probit analysis was used to determine the SAR50 in each brain area, i.e., the SAR at which 50% of maximum response was elicited. SAR50 values for the striatum, frontal cortex, and hippocampus were 0.65, 0.38, and 0.44 W/kg, respectively.

  5. Effects of low-level microwave irradiation on hippocampal and frontal cortical choline uptake are classically conditionable

    SciTech Connect

    Lai, H.; Horita, A.; Chou, C.K.; Guy, A.W.

    1987-08-01

    In previous research, we found that sodium-dependent high-affinity choline uptake in the hippocampus and frontal cortex of the rat was lowered after acute (45 min) exposure to low-level 2450-MHz pulsed microwaves (power density 1 mW/cm2; average whole body specific absorption rate, 0.6 W/kg; 2 mu sec pulses, 500 pps). In the present experiment, we investigated developments of tolerance and classical conditioning to these effects of microwaves. Rats were exposed to microwaves in cylindrical waveguides in 10 daily sessions (45 min per session). In an 11th session, we subjected the rats to either microwave (study of tolerance) or sham exposure (study of conditioned effect) for 45 min, and immediately measured choline uptake in the hippocampus and frontal cortex. We found that tolerance, a decrease in response to microwaves, developed to the effect of microwaves on choline uptake in the hippocampus, but not in the frontal cortex. Conditioned effects were also observed: an increase in choline uptake in the hippocampus and a decrease in uptake in the frontal cortex. These data suggest that the effects of microwaves on choline uptake in the hippocampus and frontal cortex are classically conditionable, probably to cues in the exposure environment.

  6. Influences of Microwave Irradiation on Environment

    NASA Astrophysics Data System (ADS)

    Murakami, H.; Abe, Y.; Iwata, T.; Kudo, I.; Saito, K.; Okuda, T.

    2004-12-01

    An experimental facility to evaluate the long-duration influence of microwave to environment, a so-called long duration microwave exposure facility (LDMEF), was constructed in Tsukuba in 1994, and so far irradiation tests on plants accumulated over 40,000 hours have been conducted with the aid of 2.45 GHz magnetron. The LDMEF consists of a pair of outdoor electromagnetically isolated areas, one under the influence of microwave irradiation with a 500 W magnetron and one without microwave irradiation. The growth rates of plants in both areas were compared and evaluated with the experimental data for the temperature distribution in the soil and power distribution of microwave. Although any appreciable influence of microwave was not noticed in the power density less than 10 mW/cm2 , the experimental results showed a significant growth rate enhancement when the power density became over 10 mW/cm2 . However, the growth was rather depressed when the power density increased over 15 mW/cm2 . These effects are well explained by the temperature and moisture in the soil which are also under an appreciable influence of microwave irradiation [1,2]. In this context, we newly constructed an indoor irradiation facility, in which the growth conditions of plants under a constant soil temperature can be maintained. In addition, irradiation with a 5.8 GHz magnetron will be conducted in the new facility. In parallel to a series of indoor and outdoor irradiation tests on plants, the influence of microwave irradiation on the growth pattern of albino mouse will be conducted. This experiment will be the first experimental evaluation for the influence of microwave irradiation on animals.

  7. Preparation of Orally Disintegrating Tablets Containing Powdered Tea Leaves with Enriched Levels of Bioactive Compounds by Means of Microwave Irradiation Technique.

    PubMed

    Tanaka, Hironori; Iwao, Yasunori; Izumikawa, Masahiro; Sano, Syusuke; Ishida, Hitoshi; Noguchi, Shuji; Itai, Shigeru

    2016-01-01

    In the present study, a microwave treatment process has been applied to prepare orally disintegrating tablets (ODTs) containing powdered tea leaves with enriched levels of the anti-inflammatory compounds such as chafuroside A (CFA) and chafuroside B (CFB). The use of distilled water as the adsorbed and granulation solvents in this preparation process afforded tablets with a long disintegration time (more than 120 s). The CFA and CFB contents of these tablets did not also change after 4 min of microwave irradiation due to the tablet temperature, which only increased to 100°C. In contrast, the tablet temperature increased up to 140°C after 3 min of microwave irradiation when a 1.68 M Na2HPO4 solution instead of distilled water. Notably, the disintegration time of these tablets was considerably improved (less than 20 s) compared with the microwave-untreated tablets, and there were 7- and 11-fold increases in their CFA and CFB contents. In addition, the operational conditions for the preparation of the tablets were optimized by face-centered composite design based on the following criteria: tablet hardness greater than 13 N, disintegration time less than 30 s and friability less than 0.5%. The requirements translated into X1 (the amount of granulation solvent), X2 (tableting pressure) and X3 (content of the powdered tea leaves) values of 45%, 0.43 kN and 32%, respectively, and the ODTs containing powdered tea leaves prepared under these optimized conditions were found to show excellent tablet properties and contain enriched levels of CFA and CFB. PMID:27581633

  8. Influence of microwave irradiation on enzyme kinetics

    NASA Astrophysics Data System (ADS)

    Pavelkić, V. M.; Stanisavljev, D. R.; Gopčević, K. R.; Beljanski, M. V.

    2009-09-01

    The in vitro effect of 2.45 GHz microwave irradiation on porcine pepsin activity under controlled temperature and absorbed microwave power via kinetic parameters was evaluated. Kinetic study with respect of time of irradiation demonstrated the existence of an inactivation effect of microwaves at pH 2 on pepsin molecule. Bovine serum albumin (BSA)-bromphenol blue (BPB) complex was used as substrate for the assay of pepsin by kinetic method. Depending on absorbed microwave dose, the degree of caused inactivation varies from 39.11 to 45.91% for 5 and 20 min of pepsin MW irradiation, respectively. The V maxapp and K mapp were calculated for low (5 min of MW irradiation) and higher specific absorbed dose (20 min of MW irradiation), as well as for untreated enzyme, from double reciprocal Lineweaver-Burk plot. The effect of microwaves on substrate (BSA-BPB complex) was also investigated. For reaction performed with MW irradiated substrate for 5 min the reaction rate was decreased for 15.15%, while for 20 min of substrate irradiation reaction rate was decreased for 25.52% compared to the control reaction.

  9. Microwave Irradiation on Halloysite-Polypropylene Nanocomposites

    NASA Astrophysics Data System (ADS)

    Espino, Omar; Yust, Brian; Chipara, Dorina; Ajayan, Pullickel; Chipara, Alin; Chipara, Mircea; Utrgv Collaboration; Rice Collaboration

    Halloysite is an unique cyllindrical nanoclay characterized by poor electrical and thermal conductivity, which may become the filler of choice for the reinforcement of polymeric matrix, where electrical or thermal insulation are required. The main limits in the use of halloysite as replacement for carbon nanotube (CNT) are: 1. Smaller aspect ratio as halloysites are typically shorter than CNTs. 2. Smaller Young modulus of halloysites compared with CNTs. 3. Reduced thermal stability due to the loss of water upon heating. A research on halloysite dispersed within isotactic polypropylene is reported. To improve the interface between the halloysite and the polymeric matrix a microwave irradiation step has been considered. The local heating of the halloysite nanotubes is mediated by the absorbed/structural water content of the nanoclay. Nanocomposites loaded by various amounts of halloysite ranging from 0 % to 20 % wt. have been prepared by melt mixing by using a Haake RheoMixer. The as obtained nanocomposites have been subjected to microwave irradiation at 75 W in an Anton Paar Monowave 300 system and various irradiation times ranging from 5, 10, 15, 30, 45, and 60 minutes. The effect of microwave irradiation has been studied by Raman and FTIR spectroscopy

  10. EXPEDITIOUS SYNTHESIS OF IONIC LIQUIDS USING ULTRASOUND AND MICROWAVE IRRADIATION

    EPA Science Inventory

    Environmentally friendlier preparations of ionic liquids have been developed that proceed expeditiously under the influence of microwave or ultrasound irradiation conditions using neat reactants, alkylimidazoles and alkyl halides. A number of useful ionic liquids have been prepar...

  11. MICROWAVE IRRADIATION FOR RAPID KILLING AND FIXING OF PLANT TISSUE

    EPA Science Inventory

    Irradiation by microwaves allow for rapid billing and fixing of plant tissue, with excellent cellular integrity for histological examination. One or two exposures to microwaves for three seconds in formalin/acetic acid/alcohol gave good preservation of nuclei, chloroplasts and ot...

  12. EXPEDITIOUS SOLVENT-FREE ORGANIC SYNTHESES USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Microwave-expedited solvent-free synthetic processes involve the exposure of neat reactants to microwave (MW) irradiation in the presence of supported reagents or catalysts on mineral oxides. Recent developments are described and the salient features of these high yield protocol...

  13. Bioethanol production from Ficus religiosa leaves using microwave irradiation.

    PubMed

    Klein, Miri; Griess, Ofir; Pulidindi, Indra Neel; Perkas, Nina; Gedanken, Aharon

    2016-07-15

    A microwave assisted feasible process for the production of bioethanol from Ficus religiosa leaves was developed. Under the process conditions (8 min. microwave irradiation, 1 M HCl), 10.1 wt% glucose yield was obtained from the leaves. Microwave based hydrolysis process yielded higher glucose content (10.1 wt%) compared to the conventional hydrothermal process (4.1 wt%). Upon fermentation of the hydrolysate using Baker's yeast, 3 wt% (dry wt. basis) of bioethanol was produced. PMID:27064733

  14. Orthodontic instrument sterilization with microwave irradiation

    PubMed Central

    Yezdani, Arif; Mahalakshmi, Krishnan; Padmavathy, Kesavaram

    2015-01-01

    Objective: This study was designed to evaluate the efficiency of microwave sterilization of orthodontic instruments and molar bands immersed in plain distilled water with and without oral rinse, and to ascertain the minimum time of exposure required to sterilize. Materials and Methods: The orthodontic instruments (hinged and nonhinged), molar bands and mouth mirrorsused in the patient 's mouth were selected for the study. The instruments were divided into two groups – Group I with oral rinse-set A (0.01% chlorhexidine gluconate) and set B (0.025% betadine) and Group II (included sets C and D without oral rinse). The instruments of set A, B and C were microwaved at 2,450 MHz, 800 W for 5 min, whereas, set D was microwaved for 10 min at the same above mentioned specifications. The efficacy of sterilization was assessed by stab inoculation of the instruments onto trypticase soya agar plates. The plates were checked for bacterial growth following incubation at 37 °C for 24 h. For sterility control,Geobacillus stearothermophilus (MTCC 1518) was included. Results: No growth was observed in the plates that were inoculated with the microwaved orthodontic instruments of sets A, B and D, whereas scanty bacterial growth was observed in the plates inoculatedwith the microwaved set C instruments. Conclusion: Effective sterilization was achieved when the orthodontic instruments and molar bands were immersed in distilled water without oral rinse and microwaved for 10 min as also for those that were immersed in distilled water with oral rinse and microwaved for 5 min. PMID:26015686

  15. GREENER CHEMICAL SYNTHESES USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Greener solvent-free protocols involve microwave (MW) exposure of neat reactants catalyzed by the surfaces of recyclable mineral supports such as alumina, silica and clay which are applicable to a wide range of cleavage, condensation, cyclization, oxidation and reduction reaction...

  16. 'GREENER' CHEMICAL SYNTHESIS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    A solvent-free approach that involves microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of recyclable mineral supports such as alumina, silica, clay, or 'doped' surfaces is presented which is applicable to a wide range of cleavage, condensation, cycl...

  17. 'GREENER' SOLVENT-FREE CHEMICAL SYNTHESIS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Solvent-free approach that involves microwave (MW) irradiation of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and recyclable mineral supports such as alumina, silica, clay, or 'doped' surfaces is presented which is applicable to a wide range of cleavage...

  18. Microwave Irradiation on Graphene Dispersed Within Polymeric Matrices

    NASA Astrophysics Data System (ADS)

    Cisneros, Jorge; Yust, Brian; Chipara, Mircea

    Graphene is a two dimensional nanomaterial with high thermal and electric conductivity and Young modulus. These features make graphene an ideal reinforcement for polymeric matrices. However, the mechanical features of polymer-carbon nanostructured composites are limited by the dispersion of the filler and by the delamination or microcracks initiated at the interface between the polymeric matrix and nanofiller. This last weakness can be addressed by improving the interface via chemical and physical methods. Microwave heating of graphite is a very efficient approach if the polymeric matrix does not also have a strong absorption. During the irradiation, the nanofiller is preferentially heated; the local melting of the polymer at the interface improves the interface by filling the microcracks and delaminations. Nanocomposites of polystyrene-poly(ethylene-ran-butylene)-polystyrene loaded by various amounts of graphene ranging from 0 % to 20 % wt. have been prepared by solution mixing using chloroform as solvent. The as obtained nanocomposites have been subjected to microwave irradiation in an Anton Paar Monowave 300 system operating at 75 W, for various irradiation times 5, 10, 15, 30, 45, and 60 minutes. The effect of microwave irradiation has been studied by Raman spectroscopy.

  19. Study on dehydrochlorination of waste poly (vinyl chloride) resins by microwave irradiation

    NASA Astrophysics Data System (ADS)

    Moriwaki, Saburo; Qian, Qingrong; Sunohara, Satoshi; Machida, Motoi; Tatsumoto, Hideki

    Waste poly (vinyl chloride: PVC) resins are experimentally dehydrochlorinated by microwave irradiation. The following unique results are obtained: (1) plasticizer in PVC resin absorbs microwave power more effectively than PVC polymer. The higher the plasticizer content in PVC resin, the higher is the dehydrochlorination reaction (2) low PVC polymer content materials such as cushion floor require high microwave irradiation power to secure a high dehydrochlorination yield, (3) calcium carbonate in PVC resin reacts with released hydrochloric acid gas and results calcium chloride during microwave irradiation, (4) additives in PVC resin strongly influence dehydrochlorination yield, (5) it is evidenced that the PVC copolymer is also dehydrochlorinated by microwave irradiation.

  20. Fast Transmethylation of Serum Lipids using Microwave Irradiation

    PubMed Central

    Lin, Yu Hong; Loewke, James D.; Hyun, Duk Y.; Leazer, Jay; Hibbeln, Joseph R.

    2012-01-01

    Microwave irradiation as the energy source for one–step direct transesterification of fatty acids in human serum lipids was examined in solvent system of methanol: hexane: acetyl chloride based on Lepage & Roy assay. Innovative and explosion proof single–mode or multimode microwave accelerate reaction system was employed. Recoveries were calculated as the percentage of fatty acid concentrations measured by microwave assay to those by reference method Lepage & Roy assay that utilized conductive heating at 100 °C for 60 min. At conditions of 100 °C for 1 min in Single–mode (S4–100×1), or 125 °C for 5 min in Multimode (M5–125×5), the recoveries were 100–103% for the total fatty acids and 96–106% for each categorized fatty acid, including saturates, monounsaturates, n-6 PUFA, and n-3 PUFA. For individual PUFA, the mean recoveries were 102–105% for 18:2n-6 and 18:3n-3; 99, 109, and 95% for 20:4n-6, 20:5n-3, and 22:6n-3, respectively. Thus, fatty acid concentrations determined by microwave fatty acid assay were accurate to those results by the reference method, when the microwave conditions were optimal. In summary, the microwave irradiation could replace conductive heating in one–step direct transesterification, and reduce duration from 60 min to 5 min or less. This methodology may be applied in both the absolute and relative quantification of serum total fatty acids. PMID:23015312

  1. Synthesis of nanosize BPO{sub 4} under microwave irradiation

    SciTech Connect

    Wang, Rui; Jiang, Heng; Gong, Hong; Zhang, Jun

    2012-08-15

    Highlights: ► Nanosize BPO{sub 4} are prepared under microwave-irradiation conditions. ► This reaction is only performed at less than 640 W power for 2.5–5 min. ► The particles of sample irradiated at 400 W are 40–90 nm in size and well dispersed. ► A simple, fast and green procedure for synthesis of nanosize BPO{sub 4} is developed. -- Abstract: Nanosize BPO{sub 4} was synthesized using H{sub 3}BO{sub 3} and H{sub 3}PO{sub 4} (85%) as raw materials under microwave irradiation. This reaction was performed at powers lower than 640 W and irradiation time ranging from 2.5 min to 5 min, which were only a fraction of the time required for conventional synthetic procedures. The structure of the as-prepared BPO{sub 4} is analogous to that of a high cristobalite. The particle sizes of the samples irradiated at 640 and 400 W range from 40 nm to 90 nm and 30 nm to 60 nm, respectively. The effects of different conditions on the experimental outcome are also discussed.

  2. ADVANCES IN GREEN CHEMISTRY: CHEMICAL SYNTHESES USING MICROWAVE IRRADIATION, ISBN 81-901238-5-8

    EPA Science Inventory

    16. Abstract Advances in Green Chemistry: Chemical Syntheses Using Microwave Irradiation
    Microwave-accelerated chemical syntheses in solvents as well as under solvent-free conditions have witnessed an explosive growth. The technique has found widespread application predomi...

  3. Vaccine Biotechnology by Accelerated Electron Beam and Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Craciun, Gabriela D.; Togoe, Iulian I.; Tudor, Laurentiu M.; Martin, Diana I.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.

    2007-04-01

    A new biotechnology for obtaining a commercial vaccine that contains either Fusobacterium necrophorum (F.n.) exotoxins inactivated by accelerated electron beam (EB) and microwave (MW) irradiation, or exotoxins isolated from F.n. cultures irradiated with EB+MW, is presented. This vaccine is designed for prophylaxis of ruminant infectious pododermatitis (IP) produced by F.n. Also, the research results concerning the effects of combined chemical adjuvant and EB+MW irradiation on F.n. immune capacity are discussed. The vaccine's efficacy will be tested in ruminant farms in which IP evolves. It is expected that this new vaccine to offer a better protection, more than 60%, which is the best presently obtained result in ruminant farms.

  4. Microwave Irradiation of Nanohydroxyapatite from Chicken Eggshells and Duck Eggshells

    PubMed Central

    Sajahan, Nor Adzliana; Wan Ibrahim, Wan Mohd Azhar

    2014-01-01

    Due to similarity in composition to the mineral component of bones and human hard tissues, hydroxyapatite with chemical formula Ca10(PO4)6(OH)2 has been widely used in medical field. Both chicken and duck eggshells are mainly composed of calcium carbonate. An attempt has been made to fabricate nanohydroxyapatite (nHA) by chicken (CES) and duck eggshells (DES) as calcium carbonate source (CaCO3). CES and DES were reacted with diammonium hydrogen [(NH4)2HPO4] solution and subjected to microwave heating at 15 mins. Under the effect of microwave irradiation, nHA was produced directly in the solution and involved in crystallographic transformation. Sample characterization was done using by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). PMID:25383364

  5. Effect of microwave irradiation on selective heating behavior and magnetic separation characteristics of Panzhihua ilmenite

    NASA Astrophysics Data System (ADS)

    Zhao, Wei; Chen, Jin; Chang, Xiaodong; Guo, Shenghui; Srinivasakannan, C.; Chen, Guo; Peng, Jinhui

    2014-05-01

    The influences of microwave irradiation on the surface characteristics of Panzhihua ilmenite were systematically investigated. The crystal structures, surface morphology and surface chemical functional groups of ilmenite were characterized before and after microwave irradiation and magnetic separation for different microwave treatment times by using various methods, such as XRD, SEM, and FT-IR, respectively. XRD analysis showed that the microwave treated ilmenite has the strongest peaks of phase more than that of raw samples, indicates that the crystalline compound of ilmenite increased with the microwave irradiation time. SEM analysis showed the micro-cracking appeared at many grain boundaries of ilmenite after being pretreated by microwave treatment. The separations of ilmenite from gangue minerals were completed and the micro-fissure within ilmenite minerals were also formed, which could be attributed to the microwave selective heating characteristics of the different minerals and compounds, and the thermal stresses were caused by the uniform heat rate disturbed under microwave irradiation. The mineral processing results showed that the magnetic separation characteristics and properties of microwave treated ilmenite samples were better than that of microwave untreated ilmenite samples. It was concluded that microwave irradiation can be applied effectively and efficiently to the irradiation processes of Panzhihua ilmenite.

  6. Controlled synthesis of novel octapod platinum nanocrystals under microwave irradiation

    SciTech Connect

    Dai, Lei; Chi, Quan; Zhao, Yanxi; Liu, Hanfan; Zhou, Zhongqiang; Li, Jinlin; Huang, Tao

    2014-01-01

    Graphical abstract: Under microwave irradiation, novel octapod Pt nanocrystals were synthesized by reducing H{sub 2}PtCl{sub 6} in TEG with PVP as a stabilizer. The as-prepared Pt nanocrystals displayed a unique octapod nanostructure with five little mastoids in each concave center. The use of KI was crucial to the formation of novel Pt octapods. Novel Octapod Platinum Nanocrystals. - Highlights: • A novel octapod Pt nanocrystals different from the common octapod were obtained. • The use of KI was crucial to the formation of the novel Pt octapods. • Microwave was readily employed in controlled synthesis of the novel Pt octapods. - Abstract: Microwave was employed in the shape-controlled synthesis of Pt nanoparticles. Novel octapod Pt nanocrystals enclosed with (1 1 1) facets were readily synthesized with H{sub 2}PtCl{sub 6} as a precursor, tetraethylene glycol (TEG) as both a solvent and a reducing agent, polyvinylpyrrolidone (PVP) as a stabilizer in the presence of an appropriate amount of KI under microwave irradiation for 140 s. The as-prepared Pt nanocrystals displayed a unique octapod nanostructure with five little mastoids in each concave center and exhibited higher electrocatalytic activity than commercial Pt black in the electro-oxidations of methanol and formic acid. The results demonstrated that the use of KI was crucial to the formation of Pt octapods. KI determined the formation of the novel octapod Pt nanocrystals by tuning up the reduction kinetics and adsorbing on the surfaces of growing Pt nanoparticles. The optimum molar ratio of H{sub 2}PtCl{sub 6}/KI/PVP was 1/30/45.

  7. An evaluation of the effect of microwave irradiation on bone decalcification aimed to DNA extraction.

    PubMed

    Imaizumi, Kazuhiko; Taniguchi, Kei; Ogawa, Yoshinori

    2013-09-01

    An effect of intermittent microwave irradiation on decalcification of compact bone followed by DNA extraction was verified. In order to perform quantitative analysis regarding the degree of decalcification, Cubic bone specimens were prepared from bovine metacarpal bone and micro-focus X-ray CT imaging was applied to measure precise volume of decalcified area in the cubes. Microwave irradiation was performed under strict control of temperature using commercially available experimental device which is designed for advancing tissue fixation, decalcification, and antigen-antibody reaction by intermittent microwave. The integrity of the DNA obtained from irradiated specimen was also examined by PCR analysis. The results of morphological analysis with CT imaging showed that microwave irradiation has a positive effect on decalcification though that effect is not so drastic. The results obtained from PCR analysis showed that microwave irradiation decrease amplifiable DNA, suggesting that we should be careful to use microwave for the purpose of bone DNA extraction. PMID:23838266

  8. Microwave irradiation biodiesel processing of waste cooking oil

    NASA Astrophysics Data System (ADS)

    Motasemi, Farough; Ani, Farid Nasir

    2012-06-01

    Major part of the world's total energy output is generated from fossil fuels, consequently its consumption has been continuously increased which accelerates the depletion of fossil fuel reserves and also increases the price of these valuable limited resources. Biodiesel is a renewable, non-toxic and biodegradable diesel fuel which it can be the best environmentally friendly and easily attainable alternative for fossil fuels. The costs of feedstock and production process are two important factors which are particularly against large-scale biodiesel production. This study is intended to optimize three critical reaction parameters including intensity of mixing, microwave exit power and reaction time from the transesterification of waste cooking oil by using microwave irradiation in an attempt to reduce the production cost of biodiesel. To arrest the reaction, similar quantities of methanol/oil molar ratio (6:1) and potassium hydroxide (2% wt) as the catalyst were used. The results showed that the best yield percentage (95%) was obtained using 300W microwave exit power, 300 rpm stirrer speed (intensity of mixing) and 78°C for 5 min. It was observed that increasing the intensity of mixing greatly ameliorates the yield percentage of biodiesel (up to 17%). Moreover, the results demonstrate that increasing the reaction time in the low microwave exit power (100W) improves the yield percentage of biodiesel, while it has a negative effect on the conversion yield in the higher microwave exit power (300W). From the obtained results it was clear that FAME was within the standards of biodiesel fuel.

  9. Changes in thermoregulatory behavior during microwave irradiation

    SciTech Connect

    Adair, E.R.

    1981-10-01

    Voluntary behavioral action is an organism's first defense against exogenous thermal challenge. Endotherms and ectotherms alike use behavioral strategies whenever possible to counteract inhospitable alterations in the exchange of thermal energy between their bodies and the environment. Responses as diverse as the thermotropisms of unicellular organisms and the complex behavior-plus-technology of man's lunar walk share a common purpose--that of providing a hospitable microclimate so that the internal body temperature may be regulated with precision at a characteristic (neutral) level. For ectothermic species, these behaviors represent most of the thermoregulatory response available to the organism. For endothermic species, these behaviors represent most of the thermoregulatory response available to the organism. For endothermic species, these behaviors ensure minimal involvement of innate mechanisms of heat production and heat loss during thermoregulation, thus conserving the body's energy stores and water.

  10. Gold Nanoparticles and Microwave Irradiation Inhibit Beta-Amyloid Amyloidogenesis

    NASA Astrophysics Data System (ADS)

    Araya, Eyleen; Olmedo, Ivonne; Bastus, Neus G.; Guerrero, Simón; Puntes, Víctor F.; Giralt, Ernest; Kogan, Marcelo J.

    2008-11-01

    Peptide-Gold nanoparticles selectively attached to β-amyloid protein (Aβ) amyloidogenic aggregates were irradiated with microwave. This treatment produces dramatic effects on the Aβ aggregates, inhibiting both the amyloidogenesis and the restoration of the amyloidogenic potential. This novel approach offers a new strategy to inhibit, locally and remotely, the amyloidogenic process, which could have application in Alzheimer’s disease therapy. We have studied the irradiation effect on the amyloidogenic process in the presence of conjugates peptide-nanoparticle by transmission electronic microscopy observations and by Thioflavine T assays to quantify the amount of fibrils in suspension. The amyloidogenic aggregates rather than the amyloid fibrils seem to be better targets for the treatment of the disease. Our results could contribute to the development of a new therapeutic strategy to inhibit the amyloidogenic process in Alzheimer’s disease.

  11. [Characteristics of high solid content sludge with microwave irradiation].

    PubMed

    Qiao, Wei; Wang, Wei; Xun, Rui; Zhou, Gang; Wan, Xiao; Xia, Zhou

    2008-06-01

    This paper focus on changes of high solid content sludge (7%, 9% and 13%) hydrolysis with microwave irradiation also anaerobic biodegradation of treated sludge was tested by biochemical methane potential (BMP) procedure. Results showed that microwave irradiation provided a rapid temperature increasing. Hydrolysis accelerated the solubilization of volatile suspended solid (VSS) and suspended solid (SS). COD, TOC, NH4+-N, TN, and TP concentration of liquor sludge increased, while pH decreased. Sludge solid content was found to be the most influential parameter. VSS and SS dissolving ratio of sludge with 13% solid content were lower than sludge with 7% and 9% solid content. 23% of VSS and 18% of SS dissolved for 9% sludge at 170 degrees C with 5 min, SCOD of liquor was 41 g/L, and concentration of TOC and NH4+-N were 30 g/L and 1 g/L respectively. Biodegradation of treated sludge improved. Methane production of 9% sludge at 170 degrees C with 5 min and 10 min were 27% and 30.8% higher than that of untreated sludge. Hydrolysis time increasing from 5 min to 10 min brought an improvement of 4%, 3.6% and 5.7% methane production at 120 degrees C, 150 degrees C and 170 degrees C. PMID:18763510

  12. Comparison of chromatographic band profiles obtained under microwave irradiated and non-irradiated reversed-phase liquid chromatography column

    SciTech Connect

    Galinada, Wilmer; Guiochon, Georges A

    2005-08-01

    The possible influence of the application of microwave energy to a reversed-phase liquid chromatography column on the mass transfer kinetics and the thermodynamics of equilibrium between mobile and stationary phases was examined. Chromatograms of propylbenzene and phenol were recorded under the same experimental conditions, on the same column, successively irradiated and not. The effect of microwave irradiation on the mass transfer kinetics was determined by measuring the second moment of small pulses of propylbenzene in a 70:30 (v/v) solution of methanol in water and microwave outputs of 15 and 30 W. The effect of microwave irradiation on the equilibrium thermodynamics was determined by measuring the elution time of breakthrough curves of phenol at high concentrations in a 20:80 (v/v) solution of methanol and water and microwave outputs of 15, 50, and 150 W. A qualitative comparison of the profiles of the propylbenzene peaks obtained with and without irradiation suggests that this irradiation affects significantly the peak shapes. However, a qualitative comparison of the profiles of the breakthrough curves of phenol obtained with and without irradiation suggests that this irradiation has no significant effect on their shapes. The peak sharpening observed may be due to an increase in the diffusivity, resulting from the dielectric polarization under microwave irradiation. This effect is directly related to an increase of the rate of mass transfers in the column. In contrast, the similarity of the overloaded band profiles at high concentrations suggests that the equilibrium thermodynamics is unaffected by microwave irradiation. This may be explained by the transparence of the stationary phase to microwaves at 2.45 GHz. The column temperature was measured at the column outlet under irradiation powers of 15, 30, 50, and 150 W. It increases with increasing power, the corresponding effluent temperatures being 25 {+-} 1, 30 {+-} 1, 35 {+-} 1, and 45 {+-} 1 C, respectively.

  13. Synergistic Effects of Combined Electron Beam and Microwave Irradiation on Microorganisms Inactivation

    NASA Astrophysics Data System (ADS)

    Craciun, Gabriela D.; Martin, Diana I.; Manaila, Elena N.; Togoe, Iulian I.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Ighigeanu, Adelina I.; Oproiu, Constantin V.

    2007-04-01

    Comparative results obtained by using separate and combined electron beam (EB) and microwave (MW) on microorganisms inactivation in natural products such as minced beef, wheat bran, wheat flour and sewage sludge are presented. The combination of advantages of both, EB and MW, in microbiological decontamination process, i.e. the EB high efficiency and MW high selectivity and volumetric heating assures higher material microbiological safety, extends the kind range of microorganisms to be inactivated, reduces the absorbed dose level and irradiation time, and decreases the process costs.

  14. Pyrolysis of Municipal Solid Waste for Syngas Production by Microwave Irradiation

    SciTech Connect

    Gedam, Vidyadhar V.; Regupathi, Iyyaswami

    2012-03-15

    In the present study, we discuss the application of microwave-irradiated pyrolysis of municipal solid waste (MSW) for total recovery of useful gases and energy. The MSW pyrolysis under microwave irradiation highly depends on the process parameters, like microwave power, microwave absorbers, and time of irradiation. The thoroughness of pyrolysis and product recovery were studied by changing the abovesaid variables. Pyrolysis of MSW occurs in the power rating range of 450-850 W-outside this power rating range, pyrolysis is not possible. Experiments were carried out using various microwave absorbers (i.e., graphite, charcoal, and iron) to enhance the pyrolysis even at lower power rating. The results show that the pyrolysis of MSW was possible even at low power ratings. The major composition of the pyrolysis gaseous product were analyzed with GC-MS which includes CO{sub 2}, CO, CH{sub 4}, etc.

  15. Speedy fabrication of diameter-controlled Ag nanowires using glycerolunder microwave irradiation conditions

    EPA Science Inventory

    Diameter-controlled Ag nanowires were rapidly fabricated (1 min) using inexpensive, abundant, and environmentally-friendly glycerol as both reductant and solvent under non-stirred microwave irradiation conditions; no Ag particles were formed using conventional heating methods. Th...

  16. Magnetically separable nanoferrite-anchored glutathione: Aqueous homocoupling of arylboronic acids under microwave irradiation

    EPA Science Inventory

    A highly active, stable and magnetically separable glutathione based organocatalyst provided good to excellent yields to symmetric biaryls in the homocoupling of arylboronic acids under microwave irradiation. Symmetrical biaryl motifs are present in a wide range of natural p...

  17. GREENER AND CONTROLLED SYNTHESIS OF NOBLE NANOSTRUCTURES IN AQUEOUS MEDIA USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Microwave-assisted spontaneous reduction of gold salts is described using sugar solutions such as alpha-D-glucose, sucrose and maltose, etc. The expeditious reactions are conducted in aqueous media using microwave irradiation wherein the reduction occurs within 30 to 60 seconds ...

  18. ENVIRONMENTALLY BENIGN ORGANIC TRANSFORMATIONS USING MICROWAVE IRRADIATION UNDER SOLVENT-FREE CONDITIONS

    EPA Science Inventory

    Microwave-expedited solvent-free synthetic processes involve the exposure of neat reactants to microwave (MW) irradiation in the presence of supported reagents or catalysts on mineral oxides. Recent developments are described and the salient features of these high yield protocols...

  19. SOLVENT-FREE APPROACH TO EXPEDITIOUS ORGANIC SYNTHESES USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Microwave irradiation has been used for a variety of organic transformations wherein chemical reactions are accelerated because of selective adsorption of microwave (MW) energy by polar molecules, non-polar molecules being inert to the MW dielectric loss. The application of MW ir...

  20. Microwave radiation, in the absence of hyperthermia, has no detectable effect on synapsin I levels or phosphorylation

    SciTech Connect

    Browning, M.D.; Haycock, J.W.

    1988-09-01

    Recent reports have indicated that microwave radiation can produce effects on a variety of cell types in vitro. To determine whether microwave radiation might be neurotoxic, the effects of microwave radiation on synapsin I have been examined. Synapsin I is a neuron-specific phosphoprotein that is present in all neurons, where it is localized to the presynaptic terminal and is associated with synaptic vesicles. O'Callaghan and Miller have demonstrated that studies of such neuron-specific proteins can provide reliable indices of neurotoxicity. We have used a radioimmunoassay for synapsin I to determine whether microwave irradiation has any effect on the levels of synapsin I. Neither acute nor chronic exposure to microwave irradiation had any detectable effect on synapsin I levels. We have also examined the calcium-dependent phosphorylation of synapsin I in synaptosomes isolated from rats that had been subjected to microwave radiation. The phosphorylation of synapsin I in synaptosomes reflects numerous components of the presynaptic aspect of neuronal transmission. At intensities below that required to produce mild hyperthermia, no effects of microwave irradiation were seen on synapsin I phosphorylation.

  1. A 3D Level Set Method for Microwave Breast Imaging

    PubMed Central

    Colgan, Timothy J.; Hagness, Susan C.; Van Veen, Barry D.

    2015-01-01

    Objective Conventional inverse-scattering algorithms for microwave breast imaging result in moderate resolution images with blurred boundaries between tissues. Recent 2D numerical microwave imaging studies demonstrate that the use of a level set method preserves dielectric boundaries, resulting in a more accurate, higher resolution reconstruction of the dielectric properties distribution. Previously proposed level set algorithms are computationally expensive and thus impractical in 3D. In this paper we present a computationally tractable 3D microwave imaging algorithm based on level sets. Methods We reduce the computational cost of the level set method using a Jacobian matrix, rather than an adjoint method, to calculate Frechet derivatives. We demonstrate the feasibility of 3D imaging using simulated array measurements from 3D numerical breast phantoms. We evaluate performance by comparing full 3D reconstructions to those from a conventional microwave imaging technique. We also quantitatively assess the efficacy of our algorithm in evaluating breast density. Results Our reconstructions of 3D numerical breast phantoms improve upon those of a conventional microwave imaging technique. The density estimates from our level set algorithm are more accurate than those of conventional microwave imaging, and the accuracy is greater than that reported for mammographic density estimation. Conclusion Our level set method leads to a feasible level of computational complexity for full 3D imaging, and reconstructs the heterogeneous dielectric properties distribution of the breast more accurately than conventional microwave imaging methods. Significance 3D microwave breast imaging using a level set method is a promising low-cost, non-ionizing alternative to current breast imaging techniques. PMID:26011863

  2. Evaluation of direct transesterification of microalgae using microwave irradiation.

    PubMed

    Teo, Chee Loong; Idris, Ani

    2014-12-01

    Nannochloropsis sp. wet biomass was directly transesterified under microwave (MW) irradiation in the presence of methanol and various alkali and acid catalyst. Two different types of direct transesterification (DT) were used; one step and two step transesterification. The biodiesel yield obtained from the MWDT was compared with that obtained using conventional method (lipid extraction followed by transesterification) and water bath heating DT method. Findings revealed that MWDT efficiencies were higher compared to water bath heating DT by at least 14.34% and can achieve a maximum of 43.37% with proper selection of catalysts. The use of combined catalyst (NaOH and H2SO4) increased the yield obtained by 2.3-folds (water bath heating DT) and 2.87-folds (MWDT) compared with the one step single alkaline catalyst respectively. The property of biodiesel produced by MWDT has high lubricating property, good cetane number and short carbon chain FAME's compared with water bath heating DT. PMID:25463809

  3. Preparation of ultrafiltration membrane by phase separation coupled with microwave irradiation

    NASA Astrophysics Data System (ADS)

    Suryani, Puput Eka; Purnama, Herry; Susanto, Heru

    2015-12-01

    Preparation of low fouling ultrafiltration membrane is still a big challenge in the membrane field. In this paper, polyether sulfone (PES) ultrafiltration membranes were prepared by non-solvent-induced phase separation (NIPS) coupled with microwave irradiation. Polyethylene glycol (PEG) and polyethylene glycol methacrylate (PEGMA) were used as additives to improve membrane hydrophilicity. In this study, the concentration of additive, irradiation time and microwave power was varied. The membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, while the performances were tested by adsorptive and ultrafiltration fouling experiments. The results show that the irradiation time and irradiation power are very important parameter that influence the membrane characteristic. In addition, type and concentration of additive are other important parameters. The results suggest that microwave irradiation is the most important parameter influencing the membrane characteristic. Both pure water flux and fouling resistance increase with increasing irradiation time, power irradiation, and additive concentration. PES membrane with addition of 10% w/w PEG and irradiated by 130 W microwave power for 180 seconds is the best membrane performance.

  4. Preparation of ultrafiltration membrane by phase separation coupled with microwave irradiation

    SciTech Connect

    Suryani, Puput Eka; Purnama, Herry; Susanto, Heru

    2015-12-29

    Preparation of low fouling ultrafiltration membrane is still a big challenge in the membrane field. In this paper, polyether sulfone (PES) ultrafiltration membranes were prepared by non-solvent-induced phase separation (NIPS) coupled with microwave irradiation. Polyethylene glycol (PEG) and polyethylene glycol methacrylate (PEGMA) were used as additives to improve membrane hydrophilicity. In this study, the concentration of additive, irradiation time and microwave power was varied. The membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy, while the performances were tested by adsorptive and ultrafiltration fouling experiments. The results show that the irradiation time and irradiation power are very important parameter that influence the membrane characteristic. In addition, type and concentration of additive are other important parameters. The results suggest that microwave irradiation is the most important parameter influencing the membrane characteristic. Both pure water flux and fouling resistance increase with increasing irradiation time, power irradiation, and additive concentration. PES membrane with addition of 10% w/w PEG and irradiated by 130 W microwave power for 180 seconds is the best membrane performance.

  5. Application of Microwave Irradiation and Heat to Improve Gliadin Detection and Ricin ELISA Throughput with Food Samples

    PubMed Central

    Garber, Eric A. E.; Thole, Joseph

    2015-01-01

    The utility of microwave irradiation to accelerate the onset of equilibrium and improve ELISA performance was examined using ELISAs for the detection of the plant toxin ricin and gliadin. The ricin ELISA normally requires several one hour incubations at 37 °C, a total assay time of approximately five hours, and employs a complex buffer containing PBS, Tween-20®, and non-fat milk. Different energy levels and pulse designs were compared to the use of abbreviated incubation times at 37 °C for the detection of ricin in food. The use of microwave irradiation had no significant advantage over the application of heat using an oven incubator and performed worse with some foods. In contrast, a gliadin ELISA that relied on 30 min incubation steps at room temperature and a salt-based buffer performed better upon irradiation but also displayed improvement upon incubating the microtiter plate at 37 °C. Whether microwave irradiation was advantageous compared to incubation in an oven was inconclusive. However, by abbreviating the incubation time of the ricin ELISA, it was possible to cut the assay time to less than 2 hours and still display LOD values < 10 ppb and recoveries of 78%–98%. PMID:26110503

  6. Application of Microwave Irradiation and Heat to Improve Gliadin Detection and Ricin ELISA Throughput with Food Samples.

    PubMed

    Garber, Eric A E; Thole, Joseph

    2015-06-01

    The utility of microwave irradiation to accelerate the onset of equilibrium and improve ELISA performance was examined using ELISAs for the detection of the plant toxin ricin and gliadin. The ricin ELISA normally requires several one hour incubations at 37 °C, a total assay time of approximately five hours, and employs a complex buffer containing PBS, Tween-20®, and non-fat milk. Different energy levels and pulse designs were compared to the use of abbreviated incubation times at 37 °C for the detection of ricin in food. The use of microwave irradiation had no significant advantage over the application of heat using an oven incubator and performed worse with some foods. In contrast, a gliadin ELISA that relied on 30 min incubation steps at room temperature and a salt-based buffer performed better upon irradiation but also displayed improvement upon incubating the microtiter plate at 37 °C. Whether microwave irradiation was advantageous compared to incubation in an oven was inconclusive. However, by abbreviating the incubation time of the ricin ELISA, it was possible to cut the assay time to less than 2 hours and still display LOD values < 10 ppb and recoveries of 78%-98%. PMID:26110503

  7. GREENER SYNTHESIS OF HETEROCYCLIC COMPOUNDS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    An introduction of our interest in the microwave-assisted greener synthesis of a variety of heterocyclic compounds will be presented. It involves microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of recyclable mineral supports, such as alumina, sili...

  8. Mechanism for microwave heating of 1-(4‧-cyanophenyl)-4-propylcyclohexane characterized by in situ microwave irradiation NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Tasei, Yugo; Yamakami, Takuya; Kawamura, Izuru; Fujito, Teruaki; Ushida, Kiminori; Sato, Motoyasu; Naito, Akira

    2015-05-01

    Microwave heating is widely used to accelerate organic reactions and enhance the activity of enzymes. However, the detailed molecular mechanism for the effect of microwave on chemical reactions is not yet fully understood. To investigate the effects of microwave heating on organic compounds, we have developed an in situ microwave irradiation NMR spectroscopy. 1H NMR spectra of 1-(4‧-cyanophenyl)-4-propylcyclohexane (PCH3) in the liquid crystalline and isotropic phases were observed under microwave irradiation. When the temperature was regulated at slightly higher than the phase transition temperature (Tc = 45 °C) under a gas flow temperature control system, liquid crystalline phase mostly changed to the isotropic phase. Under microwave irradiation and with the gas flow temperature maintained at 20 °C, which is 25 °C below the Tc, the isotropic phase appeared stationary as an approximately 2% fraction in the liquid crystalline phase. The temperature of the liquid crystalline state was estimated to be 38 °C according to the line width, which is at least 7 °C lower than the Tc. The temperature of this isotropic phase should be higher than 45 °C, which is considered to be a non-equilibrium local heating state induced by microwave irradiation. Microwaves at a power of 195 W were irradiated to the isotropic phase of PCH3 at 50 °C and after 2 min, the temperature reached 220 °C. The temperature of PCH3 under microwave irradiation was estimated by measurement of the chemical shift changes of individual protons in the molecule. These results demonstrate that microwave heating generates very high temperature within a short time using an in situ microwave irradiation NMR spectrometer.

  9. Nanosize Mn{sub 3}O{sub 4} (Hausmannite) by microwave irradiation method

    SciTech Connect

    Apte, S.K.; Naik, S.D.; Sonawane, R.S.; Kale, B.B. . E-mail: kbbb1@yahoo.com; Pavaskar, Neela; Mandale, A.B.; Das, B.K.

    2006-03-09

    The present investigation reports, the novel synthesis of nanosize Mn{sub 3}O{sub 4} powder with nanorods using microwaves and its physicochemical characterization. The nanosize Mn{sub 3}O{sub 4} powder has been prepared using manganese nitrate as a precursor and effect of ethanolamine and ethylenediamine on particle morphology has been studied. The microwave irradiation has been carried out in the range 50-500 W and it was observed that formation of Mn{sub 3}O{sub 4} takes place at 50 W. TEM analysis demonstrated nanosize Mn{sub 3}O{sub 4} powder and nanorods with an average diameter of about 10 nm. The structural study by XRD indicates that these nano-powders have pure tetragonal phase. The phase pure samples were characterized using X-Ray Photoelectron Spectroscopy (XPS) for both Mn 2p and Mn 3s levels. The values of binding energies are consistent with the relative values reported in the literature. The metallic impurity levels have been characterized using Inductively Coupled Plasma-Optical Emission Spectrophotometer (ICP-OES)

  10. Fast and Controllable Crystallization of Perovskite Films by Microwave Irradiation Process.

    PubMed

    Cao, Qipeng; Yang, Songwang; Gao, Qianqian; Lei, Lei; Yu, Yu; Shao, Jun; Liu, Yan

    2016-03-30

    The crystal growth process significantly influences the properties of organic-inorganic halide perovskite films along with the performance of solar cell devices. In this paper, we adopted the microwave irradiation to treat perovskite films through a one-step deposition method for several minutes at a fixed output power. It is found that the specific microwave irradiation process can evaporate the solvent directly and heat perovskite film quickly. In comparison with the conventional thermal annealing process, a microwave irradiation process assisted fast and controllable crystallization of perovskite films with less energy-loss and time-consumption and therefore resulted in the enhancement in the photovoltaic performance of the corresponding solar cells. PMID:26963524

  11. Observation of bubble formation in water during microwave irradiation by dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Asakuma, Yusuke; Munenaga, Takuya; Nakata, Ryosuke

    2015-10-01

    A microwave reactor was designed for in situ observation of nano- and micro-bubbles, and size profiles during and after irradiation were measured with respect to irradiation power and time. Bubble formation in water during irradiation was observed even at temperatures below the boiling point of water. The maximum size strongly depended on radiation power and time, even at a given temperature. Nano-particles in the dispersion medium were found to play an important role in achieving more stable nucleation of bubbles around particles, and stable size distributions were obtained from clear autocorrelation by a dynamic light scattering system. Moreover, a combination of microwave induction heating and the addition of nano-particles to the dispersion medium can prevent heterogeneous nucleation of bubbles on the cell wall. Quantitative nano-bubble size profiles obtained by in situ observation provide useful information regarding microwave-based industrial processes for nano-particle production.

  12. Effects of Electron Beam and Microwave Irradiation on Human Blood Proteins

    SciTech Connect

    Martin, Diana I.; Craciun, Gabriela D.; Manaila, Elena N.; Ighigeanu, Daniel I.; Iacob, Nicusor I.; Oproiu, Constantin V.; Stan, Dana E.; Radu, Roxana R.; Margaritescu, Irina D.; Chirita, Doru I.

    2007-04-23

    The effects of separated and combined accelerated electron beam (EB) of 6.23 MeV and microwave (MW) of 2.45GHz irradiation on proteins in samples of human serum, human plasma and human integral blood are presented. Also, it was studied the effect of separate and combined EB and MW irradiation on proteins irradiated in samples of human integral blood, without and in the presence of a synthetic compound solution (S.C.S.) which is expected to exhibit various biological actions, such as to diminish or to increase the irradiation effects.

  13. ‘GREENER’ CHEMICAL SYNTHESES USING MICROWAVE IRRADIATION (PRAGUE)

    EPA Science Inventory

    'Greener' solvent-free protocols involve microwave (MW) exposure of neat reactants catalyzed by the surfaces of recyclable mineral supports such as alumina, silica and clay which are applicable to a wide range of cleavage, condensation, cyclization, oxidation and reduction reacti...

  14. EFFICIENT AND GREENER CHEMICAL SYNTHESES USING MICROWAVE IRRADIATION

    EPA Science Inventory

    The diverse nature of chemical entities requires various ‘green’ strategic pathways in our quest towards attaining sustainability. A solvent-free approach involving microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and rec...

  15. Effect of Microwave Irradiation on the Physicochemical and Digestive Properties of Lotus Seed Starch.

    PubMed

    Zeng, Shaoxiao; Chen, Bingyan; Zeng, Hongliang; Guo, Zebin; Lu, Xu; Zhang, Yi; Zheng, Baodong

    2016-03-30

    The objective of this study is to investigate the effect of microwave irradiation on the physicochemical and digestive properties of lotus seed starch. The physicochemical properties of lotus seed starch were characterized by light microscopy, (1)H NMR, FT-IR spectroscopy, and HPSEC-MALLS-RI. The starch-water interaction and crystalline region increased due to the changed water distribution of starch granules and the increase of the double-helix structure. The swelling power, amylose leaching, molecular properties, and radius of gyration reduced with the increasing microwave power, which further affected the sensitivity of lotus seed starch to enzymatic degradation. Furthermore, the resistant starch and slowly digestible starch increased with the increasing microwave irradiation, which further resulted in their decreasing hydrolysis index and glycemic index. The digestive properties of lotus seed starch were mainly influenced by the reduced branching degree of amylopectin and the strong amylose-amylose interaction. PMID:26912092

  16. NOVEL METALLIC AND BIMETALLIC CROSS-LINKED POLY (VINYL ALCOHOL) NANOCOMPOSITES PREPARED UNDER MICROWAVE IRRADIATION

    EPA Science Inventory

    A facile microwave irradiation approach that results in a cross-linking reaction of poly (vinyl alcohol) (PVA) with metallic and bimetallic systems is described. Nanocomposites of PVA cross-linked metallic systems such as Pt, Cu, and In and bimetallic systems such as Pt-In, Ag-P...

  17. "GREENER" CHEMICAL SYNTHETIC PROCESSES USING ENZYMATIC, MECHANOCHEMICAL MIXING, OR MICROWAVE AND ULTRASOUND IRRADIATION

    EPA Science Inventory

    Several newer strategies, such as solvent-free (dry media), solid-supported with and without microwave (MW) irradiation, and mechanochemical mixing (grinding); and the use of room temperature ionic liquids, supercritical carbon dioxide, and water as reaction media that can be com...

  18. ASSESSMENT OF IMMUNE FUNCTION DEVELOPMENT IN MICE IRRADIATED IN UTERO WITH 2450-MHZ MICROWAVES

    EPA Science Inventory

    Groups of time-bred pregnant mice were irradiated with 2450-MHz microwaves at an incident power density of 28 mW/sq. cm. for 100 min daily from day 6 to day 18 of pregnancy. The average specific absorption rate (SAR) was 16.5 W/kg. Two experiments were performed under these condi...

  19. CHEMISTRY UNDER 'GREENER' CONDITIONS: SOLVENT-FREE SYNTHESIS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Solvent-free approach is emphasized that involves microwave (MW) irradiation of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and recyclable mineral supports such as alumina, silica, clay, or 'doped' surfaces which is applicable to a wide range of cleavag...

  20. Microwave oven irradiation as a method for bacterial decontamination in a clinical microbiology laboratory.

    PubMed

    Latimer, J M; Matsen, J M

    1977-10-01

    Exposure of 10 frequently isolated clinical pathogens to microwave irradiation resulted in total sterilization with 60 s. Time exposure experiments done with commercially prepared test strips containing Bacillus stearothermophilus spores indicated that 5-min exposure was adequate to insure sterility of small, contaminated loads. PMID:410828

  1. CHEMISTRY UNDER NON-TRADITIONAL CONDITIONS: SOLVENT-FREE SYNTHESIS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    A solvent-free approach that involves microwave (MW) irradiation of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and recyclable mineral supports such as alumina, silica, clay, or "doped" surfaces is presented which is applicable to a wide range of cleava...

  2. Green synthesis of noble nanometals (Au, Pt, Pd) using glycerol under microwave irradiation conditions

    EPA Science Inventory

    A newer application of glycerol in the field of nanomaterials synthesis has been developed from both the economic and environmental points of view. Glycerol can act as a reducing agent for the fabrication of noble nanometals, such as Au, Pt, and Pd, under microwave irradiation. T...

  3. Method of producing carbon monoxide and hydrogen by gasification of solid carbonaceous material involving microwave irradiation

    SciTech Connect

    Helm, J.L. Jr.

    1984-03-06

    A process is claimed for the gasification of carbon of solid carbonaceous material to form carbon monoxide and hydrogen by contacting the material with superheated steam and irradiating the product of said contacting with an amount of microwave energy sufficient to gasify said carbon, and apparatus therefor.

  4. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber

    NASA Astrophysics Data System (ADS)

    Chiang, W. Y.; Wu, M. H.; Wu, K. L.; Lin, M. H.; Teng, H. H.; Tsai, Y. F.; Ko, C. C.; Yang, E. C.; Jiang, J. A.; Barnett, L. R.; Chu, K. R.

    2014-08-01

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.

  5. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber.

    PubMed

    Chiang, W Y; Wu, M H; Wu, K L; Lin, M H; Teng, H H; Tsai, Y F; Ko, C C; Yang, E C; Jiang, J A; Barnett, L R; Chu, K R

    2014-08-01

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system. PMID:25173291

  6. A microwave applicator for uniform irradiation by circularly polarized waves in an anechoic chamber

    SciTech Connect

    Chiang, W. Y.; Wu, M. H.; Wu, K. L.; Lin, M. H.; Teng, H. H.; Barnett, L. R.; Chu, K. R.; Tsai, Y. F.; Ko, C. C.; Yang, E. C.; Jiang, J. A.

    2014-08-15

    Microwave applicators are widely employed for materials heating in scientific research and industrial applications, such as food processing, wood drying, ceramic sintering, chemical synthesis, waste treatment, and insect control. For the majority of microwave applicators, materials are heated in the standing waves of a resonant cavity, which can be highly efficient in energy consumption, but often lacks the field uniformity and controllability required for a scientific study. Here, we report a microwave applicator for rapid heating of small samples by highly uniform irradiation. It features an anechoic chamber, a 24-GHz microwave source, and a linear-to-circular polarization converter. With a rather low energy efficiency, such an applicator functions mainly as a research tool. This paper discusses the significance of its special features and describes the structure, in situ diagnostic tools, calculated and measured field patterns, and a preliminary heating test of the overall system.

  7. In situ temperature measurements of reaction spaces under microwave irradiation using photoluminescent probes.

    PubMed

    Ano, Taishi; Kishimoto, Fuminao; Sasaki, Ryo; Tsubaki, Shuntaro; Maitani, Masato M; Suzuki, Eiichi; Wada, Yuji

    2016-05-11

    We demonstrate two novel methods for the measurement of the temperatures of reaction spaces locally heated by microwaves, which have been applied here to two example systems, i.e., BaTiO3 particles covered with a SiO2 shell (BaTiO3-SiO2) and layered tungstate particles. Photoluminescent (PL) probes showing the temperature-sensitivity in their PL lifetimes are located in the nanospaces of the above systems. In the case of BaTiO3-SiO2 core-shell particles, rhodamine B is loaded into the mesopores of the SiO2 shell covering the BaTiO3 core, which generates the heat through the dielectric loss of microwaves. The inner nanospace temperature of the SiO2 shell is determined to be 28 °C higher than the bulk temperature under microwave irradiation at 24 W. On the other hand, Eu(3+) is immobilized in the interlayer space of layered tungstate as the PL probe, showing that the nanospace temperature of the interlayer is only 4 °C higher than the bulk temperature. This method for temperature-measurement is powerful for controlling microwave heating and elucidates the ambiguous mechanisms of microwave special effects often observed in chemical reactions, contributing greatly to the practical application of microwaves in chemistry and materials sciences. PMID:27136754

  8. Effect of microwave irradiation on the photoluminescence of bound excitons in CdTe:Cl single crystals

    SciTech Connect

    Korbutyak, D. V.; Lotsko, A. P.; Vakhnyak, N. D.; Demchuna, L. A.; Konakova, R. V. Milenin, V. V.; Red'ko, R. A.

    2011-09-15

    The effect of microwave radiation on the transformation of impurity-based structural complexes in Cd{sub Te}:Cl single crystals is studied using low-temperature photoluminescence measurements. It is shown that microwave radiation activates Cl{sub Te} centers, resulting in an increase in the intensity of photoluminescence line of excitons bound at the corresponding Cl{sub Te} donor centers. A nonmonotonic dependence of the integrated photoluminescence intensity on the duration of microwave irradiation is observed. At the initial stage of microwave irradiation (t = 30 s), an increase in the integrated excitonic photoluminescence intensity is observed; as the duration of microwave irradiation is increased, the photoluminescence intensity decreases. The experimentally observed variations in the photoluminescence intensity are athermal in nature. The hypothetical mechanism of transformation of impurity-based structural complexes is described.

  9. A microwave-irradiated Streptococcus agalactiae vaccine provides partial protection against experimental challenge in Nile tilapia, Oreochromis niloticus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microwave irradiation, as opposed to formalin exposure, has not routinely been used in the preparation of killed vaccines despite the advantages of decreased chemical toxicity, ability to kill cells quickly, ease of completion requiring only a standard microwave, and potential increased protein cons...

  10. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Graft copolymers of waxy maize starch and poly-y-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180 deg C and pH 7.0 were the best reaction conditions resulti...

  11. Acute microwave irradiation and cataract formation in rabbits and monkeys.

    PubMed

    Kramar, P; Harris, C; Emery, A F; Guy, A W

    1978-09-01

    Rabbits and monkeys were irradiated in the near field of a cavity-backed 2450 MHz resonant slot radiator, to determine the cataractogenic threshold. Rabbits developed cataracts at incident "apparent" power densities of 180 mW/cm2 (E2/120 pi, where E=rms/electric field strength). Monkeys sustained facial burns, but no lens damage, even at incident "apparent" power densities of 500 mW/cm2. These results were substantiated by computer thermal models. PMID:108401

  12. Whole Body Microwave Irradiation for Improved Dacarbazine Therapeutical Action in Cutaneous Melanoma Mouse Model

    PubMed Central

    Albulescu, Lucian; Iacob, Nicusor; Ighigeanu, Daniel

    2013-01-01

    A cutaneous melanoma mouse model was used to test the efficacy of a new therapeutical approach that uses low doses of cytostatics in conjunction with mild whole body microwave exposure of 2.45 GHz in order to enhance cytostatics antitumoral effect. Materials and Methods. A microwave exposure system for C57BL/6 mouse whole body microwave irradiation was designed; groups of 40 mice (males and females) bearing experimental tumours were subjected to a combined therapy comprising low doses of dacarbazine in combination with mild whole body irradiation. Clinical parameters and serum cytokine testing using xMAP technology were performed. Results. The group that was subjected to combined therapy, microwave and cytostatic, had the best clinical evolution in terms of overall survival, tumour volume, and metastatic potential. At day 14 the untreated group had 100% mortality, while in the combined therapy group 40% of mice were surviving. Quantifying serum IL-1β, IL-6, IL-10, IL-12 (p70), IFN-γ, GM-CSF, TNF-α, MIP-1α, MCP-1, and KC during tumorigenesis and therapy found that the combined experimental therapy decreases all the inflammatory cytokines, except chemokine MCP-1 that was found increased, suggesting an increase of the anti-tumoral immune response triggered by the combined therapy. The overall metastatic process is decreased in the combined therapy group. PMID:24377047

  13. Rapid Synthesis and Antiviral Activity of (Quinazolin-4-Ylamino)Methyl-Phosphonates Through Microwave Irradiation

    PubMed Central

    Luo, Hui; Hu, Deyu; Wu, Jian; He, Ming; Jin, Linhong; Yang, Song; Song, Baoan

    2012-01-01

    This study describes the simple synthesis of new (quinazolin-4-ylamino) methylphosphonates via microwave irradiation. Substituted-2-aminobenzonitrile reacted with 1,1-dimethoxy-N,N-dimethylmethanamine at a reflux condition to obtain N′-(substituted-2-cyanophenyl)-N,N-dimethylformamidine (1). The subsequent reaction of this intermediate product with α-aminophosphonate (2) in a solution containing glacial acetic acid in 2-propanol through microwave irradiation resulted in the formation of (quinazolin-4-ylamino)methyl-phosphonate derivatives 3a to 3x, which were unequivocally characterized by the spectral data and elemental analysis. The influence of the reaction conditions on the yield of 3a was investigated to optimize the synthetic conditions. The relative optimal conditions for the synthesis of 3a include a 1:1 molar ratio of N′-(2-cyanophenyl)-N,N-dimethylformamidine to diethyl amino(phenyl)methylphosphonate and a 4:1 volume ratio of isopropanol to HOAc in the solvent mixture, at a reaction temperature of 150 °C, with a microwave power of 100 W and a corresponding pressure of 150 psi for 20 min in the microwave synthesizer. The yield of 3a was approximately 79%, whereas those of 3b to 3x were approximately 77% to 86%. Some of the synthesized compounds displayed weak to good anti-Tobacco mosaic virus (TMV) activity. PMID:22837660

  14. Resonant Phase Escape from the First Resistive State of Bi2Sr2CaCu2Oy Intrinsic Josephson Junctions under Strong Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Takahashi, Yusaku; Kakehi, Daiki; Takekoshi, Shuho; Ishikawa, Kazuki; Ayukawa, Shin-ya; Kitano, Haruhisa

    2016-07-01

    We report a study of the phase escape in Bi2Sr2CaCu2Oy intrinsic Josephson junctions under the strong microwave irradiation, focusing on the switch from the first resistive state (2nd SW). The resonant double-peak structure is clearly observed in the switching current distributions below 10 K and is successfully explained by a quantum-mechanical model on the quantum phase escape under the strong microwave field. These results provide the first evidence for the formation of the energy level quantization for the 2nd SW, supporting that the macroscopic quantum tunneling for the 2nd SW survives up to ˜10 K.

  15. Artificial and enhanced humification of soil organic matter using microwave irradiation.

    PubMed

    Kim, Min Chan; Kim, Han S

    2013-04-01

    Microwave (MW) irradiation, a less energy-intensive irradiation technique, was employed to promote the changes in physicochemical properties of soil organic matter (SOM). MW was irradiated to forest soils for 10 min. Then, the physical and chemical properties of the SOM were analyzed with UV absorbance spectroscopy, Fourier transform infrared spectroscopy, elemental analysis, and size exclusion chromatography. Also, the SOM was fractionated into biopolymer, fulvic acid, and humic acid, and each fraction was analyzed quantitatively. These analyses revealed that the SOM became more aromatic and nonpolar, highly condensed, and macromolecular organic substances that possess a higher amount of functional groups found in highly humified substances than the original SOM as a result of the MW irradiation. The humification-like alteration of SOM property was attributable to the thermal cracking and to the radical reaction, particularly when the MW was irradiated along with activated carbon under the aerobic condition. The results of this study suggest that the artificial and enhanced property changes of SOM can be accomplished by MW irradiation on an engineering time scale, which can contribute to the successful soil and groundwater remediation practice. PMID:22895631

  16. Enhanced biocatalysis mechanism under microwave irradiation in isoquercitrin production revealed by circular dichroism and surface plasmon resonance spectroscopy.

    PubMed

    Gong, An; Zhu, Dan; Mei, Yi-Yuan; Xu, Xiao-Hui; Wu, Fu-An; Wang, Jun

    2016-04-01

    An efficient and rapid process for isoquercitrin production by hesperidinase-catalyzed hydrolysis of rutin was successfully developed under microwave irradiation detecting the affinity by circular dichroism (CD) and surface plasmon resonance (SPR) spectroscopy. A maximum isoquercitrin yield of 91.5±2.7% was obtained in 10min with the conditions of 10g/L hesperidinase, 2g/L rutin, 30°C and microwave power density 88.9W/L. Enzymatic reaction rate and Vm/Km in the microwave reactor were 6.34-fold higher than in a continuous flow microreactor and 1.24-fold higher than in a biphasic system. CD and SPR analysis results also showed that hesperidinase has a better selectivity and affinity (3.3-fold than in a batch reactor) to generate isoquercitrin under microwave irradiation. Microwave irradiation greatly improved the reaction efficiency and productivity, leading to a more positive economical assessment. The binding affinity indicates the presence of strong multivalent interactions between rutin and hesperidinase under microwave irradiation. PMID:26803794

  17. Degradation of N-nitrosodimethylamine (NDMA) and its precursor dimethylamine (DMA) in mineral micropores induced by microwave irradiation.

    PubMed

    He, Yuanzhen; Cheng, Hefa

    2016-05-01

    Removal of N-nitrosodimethylamine (NDMA) in drinking water treatment poses a significant technical challenge due to its small molecular size, high polarity and water solubility, and poor biodegradability. Degradation of NDMA and its precursor, dimethylamine (DMA), was investigated by adsorbing them from aqueous solution using porous mineral sorbents, followed by destruction under microwave irradiation. Among the mineral sorbents evaluated, dealuminated ZSM-5 exhibited the highest sorption capacities for NDMA and DMA, which decreased with the density of surface cations present in the micropores. In contrast, the degradation rate of the sorbed NDMA increased with the density of surface cations under microwave irradiation. Evolutions of the degradation products and C/N ratio indicate that the sorbed NDMA and DMA could be eventually mineralized under continuous microwave irradiation. The degradation rate was strongly correlated with the bulk temperature of ZSM-5 and microwave power, which is consistent with the mechanism of pyrolysis caused by formation of micro-scale "hot spots" within the mineral micropores under microwave irradiation. Compared to existing treatment options for NDMA removal, microporous mineral sorption coupled with microwave-induced degradation has the unique advantages of being able to simultaneously remove NDMA and DMA and cause their full mineralization, and thus could serve as a promising alternative method. PMID:26971806

  18. Effects of microwave irradiation on dewaterability and extracellular polymeric substances of waste activated sludge.

    PubMed

    Peng, Ge; Ye, Fenxia; Ye, Yangfang

    2013-03-01

    The effects of microwave irradiation on filterability and dewaterability of waste activated sludge measured by capillary suction time (CST) and dry solids in sludge cake were investigated. The results showed that the optimum irradiation time improved filterability, but that further increase of the time was detrimental. Dewaterability was enhanced significantly and increased with microwave time. Filterability and dewaterability were improved 25 to 28% and 1.3 times at the optimum times of 30 and 90 seconds for the sludge of 5 g total suspended solids (TSS)/L and 7 g TSS/L, respectively. The floc size decreased slightly. Loosely bound extracellular polymeric substances (LB-EPS) decreased under optimum time, but tightly bound extracellular polymeric substances did not change significantly after short irradiation time. The results implied that LB-EPS played a more important role in the observed changes of filterability and dewaterability and that the double-layered extracellular polymeric substances extraction method showed marked implications to dewaterability. PMID:23581243

  19. Microwave irradiation of human brain tissue: production of microscopic slides within one day.

    PubMed Central

    Boon, M E; Marani, E; Adriolo, P J; Steffelaar, J W; Bots, G T; Kok, L P

    1988-01-01

    A three step method using microwave irradiation enabled microscopic slides of human brain tissue to be obtained within one working day: steps 1 and 2 hardened and solidified brain tissue; step 3 completed formalin fixation. The efficacy and precision of the method was compared with slides of conventionally processed brain tissue that had been fixed in formalin for six weeks. The microscopic quality of the sections was excellent with good presentation of brain tissue and equalled that of conventionally processed slides. Images Fig 1 Fig 2 Fig 3 PMID:3290268

  20. Synthesis and characterization of some metal oxide nanocrystals by microwave irradiation

    SciTech Connect

    Rashad, M.; Gaber, A.; Abdelrahim, M. A.; Abdel-Baset, A. M.; Moharram, A. H.

    2013-12-16

    Copper oxide and cobalt oxide (CuO, Co3O4) nanocrystals (NCs) have been successfully prepared in a short time using microwave irradiation. The resulted powders of nanocrystals (NCs) were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). Thermogravimetric analysis (TGA) measurements are also studied. Fourier-transform infrared (FT-IR) and UV–visible absorption spectroscopy of both kind of nanoparticels are illustrated. Optical absorption analysis indicated the direct band gap for both kinds of nanocrystals.

  1. Enhancing the various solvent extraction method via microwave irradiation for extraction of lipids from marine microalgae in biodiesel production.

    PubMed

    Teo, Chee Loong; Idris, Ani

    2014-11-01

    The types of microalgae strains and the method used in lipid extraction have become crucial factors which influence the productivity of crude oil. In this paper, Nannochloropsis sp. and Tetraselmis sp. were chosen as the strains and four different methods were used to extract the lipids: Hara and Radin, Folch, Chen and Bligh and Dyer. These methods were performed by using conventional heating and microwave irradiation methods. Results revealed that highest lipid yield from the different species was obtained using different extraction methods; both under microwave irradiation. The lipid yield for Tetraselmis sp. and Nannochloropsis sp. was highest when Hara and Radin (8.19%), and Folch (8.47%) methods were used respectively under microwave irradiation. The lipids extracted were then transesterified to biodiesel and the quality of the biodiesel was analyzed using the gas chromatography. PMID:25201293

  2. Preparation and characterization of guluronic acid oligosaccharides degraded by a rapid microwave irradiation method.

    PubMed

    Hu, Ting; Li, Chunxia; Zhao, Xia; Li, Guangsheng; Yu, Guangli; Guan, Huashi

    2013-05-24

    Guluronic acid oligosaccharides (GOS) with degree of polymerization (DP) ranging from 1 to 10 were prepared by a rapid microwave degradation method. Polyguluronic acid, fractionated from alginate hydrolysate, was dissolved in dilute ammonia water at a concentration of 20 mg/mL (pH 5) and then hydrolyzed under microwave irradiation (1600 W) at 130°C for 15 min to produce GOS mixture. The GOS mixture was separated by a Bio-Gel P6 column and ten fractions were obtained. Each GOS fraction was further characterized by electrospray ionization mass spectrometry, (1)H NMR, (13)C NMR, and 2D NMR spectroscopy techniques. The data showed that the GOS fractions were saturated oligoguluronates with general molecular formula C(6n)H(8n+2)O(6n+1) (n=1-10). This microwave degradation method was not only convenient, less time consuming, and environment-friendly, but also produced GOS with high yield (71%) and eliminating a desalting procedure compared to conventional acid hydrolysis method. PMID:23584235

  3. Controlled synthesis of snowflake-like self-assemblies palladium nanostructures under microwave irradiation

    SciTech Connect

    Xie, Ting; Ma, Yue; Yang, Hanmin Li, Jinlin

    2013-08-01

    Graphical abstract: - Highlights: • We demonstrated the synthesis of snowflake-like palladium nanostructures for the first time. • We discussed the influencing factors on the synthesis of snowflake-like Pd nanostructures. • The molar ratio of H{sub 2}Pd{sub 4} to PVP at 5 is the optimal selection. • The growth process was discussed. - Abstract: Self-assembly snowflake-like palladium nanostructures were synthesized under microwave irradiation using H{sub 2}PdCl{sub 4} as precursor, benzyl alcohol as both solvent and reducing agent, and PVP as stabilizer. The Pd snowflake-like nanostructures were formed and then characterized by transmission electron microscopy (TEM) and X-ray powder diffraction. The TEM images showed that the Pd nano-snowflakes were self-assemblies organized by hundreds of small spherical nanoparticles. Pd snowflake-like nanostructures with well-defined shape and uniform size can be obtained by tuning the concentration of palladium precursor, the molar ratio of H{sub 2}PdCl{sub 4}/PVP, as well as the heating time by microwave irradiation. The possible growing process of the snowflake-like Pd structures was also proposed on the basis of investigating the properties of as-synthesized Pd nanostructures under different conditions.

  4. An efficient combination of Zr-MOF and microwave irradiation in catalytic Lewis acid Friedel-Crafts benzoylation.

    PubMed

    Doan, Tan L H; Dao, Thong Q; Tran, Hai N; Tran, Phuong H; Le, Thach N

    2016-05-01

    A zirconium-based metal-organic framework, an effective heterogeneous catalyst, has been developed for the Friedel-Crafts benzoylation of aromatic compounds under microwave irradiation. Constructed by a Zr(iv) cluster and a linker 1,4-bis(2-[4-carboxyphenyl]ethynyl)benzene (H2CPEB), the MOF, possessing large pores and high chemical stability, was appropriate for the enhancement of Lewis acid activity under microwave irradiation. The reaction studies demonstrated that the material could give high yields for a few minutes and maintain its reactivity and structure over several cycles. PMID:27064371

  5. Influence of microwave irradiation on the mass-transfer kinetics of propylbenzene in reversed-phase liquid chromatography

    SciTech Connect

    Galinada, Wilmer; Kaczmarski, Krzysztof; Guiochon, Georges A

    2005-09-01

    The effect of microwave irradiation on the kinetics of mass transfer in reversed-phase liquid chromatography (RPLC) was studied by measuring its influence on the band profile of propylbenzene in a C{sub 18}-silica column eluted with an aqueous solution of methanol and placed inside a microwave oven. The elution peaks were measured by the pulse-response method, under linear conditions. The amount of microwave energy induced into the column was varied based on the microwave input power. The experimental data were analyzed using the conventional method of moment analysis and the lumped pore diffusion model. With input powers of 15 and 30 W, the effluent temperatures were 25 {+-} 1 and 30 {+-} 1 C, respectively. The effect of microwave irradiation on the mass transfer of the studied solute was determined by comparing the band profiles obtained under the same experimental conditions, at the same temperature, with and without irradiation. The values of the intraparticle diffusion coefficient, D{sub e}, measured with microwave irradiation were ca. 20% higher than those obtained without irradiation. Derived from the method of moments, the values of D{sub e} at 15 W (25 {+-} 1 C) and 0 W (25 {+-} 1 C) were 8.408 x 10{sup -6} cm{sup 2} s{sup -1} and 6.947 x 10{sup -6} cm{sup 2} s{sup -1}, respectively, while these values at 30 W (30 {+-} 1 C) and 0 W (30 {+-} 1 C) were 9.389 x 10{sup -6} cm{sup 2} s{sup -1} and 7.848 x 10{sup -6} cm{sup 2} s{sup -1}, respectively. The values of the surface diffusivity, D{sub S}, also increased with increasing power of the microwave irradiation. It is assumed that the increase in intraparticle diffusion for propylbenzene was caused by the molecular excitation of the organic modifier that has a higher dielectric loss than the solute. The values of D{sub e} were also analyzed and determined using the POR model. There was an excellent agreement between the results of the two independent methods. These preliminary results suggest that microwave

  6. Microwave energy for post-calcination treatment of high-level nuclear wastes

    SciTech Connect

    Gombert, D.; Priebe, S.J.; Berreth, J.R.

    1980-01-01

    High-level radioactive wastes generated from nuclear fuel reprocessing require treatment for effective long-term storage. Heating by microwave energy is explored in processing of two possible waste forms: (1) drying of a pelleted form of calcined waste; and (2) vitrification of calcined waste. It is shown that residence times for these processes can be greatly reduced when using microwave energy rather than conventional heating sources, without affecting product properties. Compounds in the waste and in the glass frit additives couple very well with the 2.45 GHz microwave field so that no special microwave absorbers are necessary.

  7. Photocatalytic Decomposition of Methylene Blue Over MIL-53(Fe) Prepared Using Microwave-Assisted Process Under Visible Light Irradiation.

    PubMed

    Trinh, Nguyen Duy; Hong, Seong-Soo

    2015-07-01

    Iron-based MIL-53 crystals with uniform size were successfully synthesized using a microwave-assisted solvothermal method and characterized by XRD, FE-SEM and DRS. We also investigated the photocatalytic activity of MIL-53(Fe) for the decomposition of methylene blue using H2O2 as an electron acceptor. From XRD and SEM results, the fully crystallized MIL-53(Fe) materials were obtained regardless of preparation method. From DRS results, MIL-53(Fe) samples prepared using microwave-assisted process displayed the absorption spectrum up to the visible region and then they showed the high photocatalytic activity under visible light irradiation. The MIL-53(Fe) catalyst prepared by two times microwave irradiation showed the highest activity. PMID:26373158

  8. Ionic liquid as a promising biobased green solvent in combination with microwave irradiation for direct biodiesel production.

    PubMed

    Wahidin, Suzana; Idris, Ani; Shaleh, Sitti Raehanah Muhamad

    2016-04-01

    The wet biomass microalgae of Nannochloropsis sp. was converted to biodiesel using direct transesterification (DT) by microwave technique and ionic liquid (IL) as the green solvent. Three different ionic liquids; 1-butyl-3-metyhlimidazolium chloride ([BMIM][Cl], 1-ethyl-3-methylimmidazolium methyl sulphate [EMIM][MeSO4] and 1-butyl-3-methylimidazolium trifluoromethane sulfonate [BMIM][CF3SO3]) and organic solvents (hexane and methanol) were used as co-solvents under microwave irradiation and their performances in terms of percentage disruption, cell walls ruptured and biodiesel yields were compared at different reaction times (5, 10 and 15 min). [EMIM][MeSO4] showed highest percentage cell disruption (99.73%) and biodiesel yield (36.79% per dried biomass) after 15 min of simultaneous reaction. The results demonstrated that simultaneous extraction-transesterification using ILs and microwave irradiation is a potential alternative method for biodiesel production. PMID:26851899

  9. Phenolic Content and Antioxidant Activity of Extracts from Whole Buckwheat (Fagopyrum esculentum Moench) With or Without Microwave Irradiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study was to evaluate the effectiveness of extracting phenolic compounds and antioxidant activity from buckwheat with water, 50% aqueous ethanol, or 100% ethanol using microwave irradiation or a water bath for 15 min at various temperatures (23 – 150 °C). The phenolic content of...

  10. Microwave emission by nonlinear crystals irradiated with a high-intensity, mode-locked laser

    NASA Astrophysics Data System (ADS)

    Borghesani, A. F.; Braggio, C.; Guarise, M.

    2016-06-01

    We report on the experimental investigation of the efficiency of some nonlinear crystals to generate microwave (RF) radiation as a result of optical rectification (OR) when irradiated with intense pulse trains delivered by a mode-locked laser at 1064 nm. We have investigated lithium triborate (LBO), lithium niobate (LiNbO3), zinc selenide (ZnSe), and also potassium titanyl orthophosphate (KTP) for comparison with previous measurements. The results are in good agreement with the theoretical predictions based on the form of the second-order nonlinear susceptibility tensor. For some crystals we investigated also the second harmonic generation (SHG) to cross check the theoretical model. We confirm the theoretical prediction that OR leads to the production of higher order RF harmonics that are overtones of the laser repetition rate.

  11. Changes of amino acid gradients in brain tissues induced by microwave irradiation and other means

    SciTech Connect

    Baxter, C.F.; Parsons, J.E.; Oh, C.C.; Wasterlain, C.G.; Baldwin, R.A. )

    1989-09-01

    Focused microwave irradiation to the head (FMI) has been used extensively by neurochemists for rapid inactivation of enzymatic activity in brain tissues and the preservation, for in vitro analysis, of in vivo substrate concentrations. Periodically the suitability of this technique for regional studies has been questioned. Evidence has now been obtained, on the basis of altered concentration gradients for GABA and taurine from the Substantia Nigra (SN) to an Adjacent Dorsal Area (ADJ), that FMI not only inactivates enzymes, but also facilitates rapid diffusion of small molecules from areas of high concentrations to adjacent areas of lower concentration. To a lesser extent, the implantation of plastic injection cannulas also decreased these concentration gradients. These results offer clear evidence that FMI is ill suited and unreliable for studies designed to map and compare the in vivo regional concentrations of diffusible organic molecules (such as amino acids) in brain tissues. Any invasive technique that compromises membrane barriers is likely to produce smaller similar effects.

  12. Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities

    PubMed Central

    Velusamy, Palaniyandi; Su, Chia-Hung; Venkat Kumar, Govindarajan; Adhikary, Shritama; Pandian, Kannaiyan; Gopinath, Subash C. B.; Chen, Yeng; Anbu, Periasamy

    2016-01-01

    In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications. PMID:27304672

  13. Rapid synthesis of gold nanoparticles with Cissus quadrangularis extract using microwave irradiation

    NASA Astrophysics Data System (ADS)

    Bhuvanasree, S. R.; Harini, D.; Rajaram, Anantanarayanan; Rajaram, Rama

    2013-04-01

    The present study focuses on the rapid synthesis of gold nanoparticles (AuNP) using the aqueous extract of Cissus quadrangularis (CQE) by microwave irradiation. The UV-Visible spectroscopy of the solution obtained from reduction of hydrogen tetrachloroaurate (HAuCl4) by CQE revealed a sharp surface plasmon resonance (SPR) peak at 530 nm confirming the presence of AuNP. The formation of AuNP was optimal at a pH of 9. The AuNP was characterised by FT-IR, SEM, HR-TEM, SAED, XRD, TGA, DLS and Zeta potential measurements. The results indicated that microwave assisted synthesis produced well dispersed, small sized, uniform nanoparticles when compared to conventional room temperature synthesis. The spherical nanoparticle had an average size of 12.0 ± 3.2 nm as revealed through TEM. The crystalline nature of AuNP was confirmed through HR-TEM, SAED and XRD. The FT-IR and TGA data revealed the presence of the CQE components on the surface of the AuNP particles which serve as the capping agent. Upon incubation, the particles did not lyse the red blood corpuscles (RBCs) indicating that they are biocompatible. A possible mechanism for the formation of AuNP in the presence of CQE is proposed.

  14. Biopolymers Regulate Silver Nanoparticle under Microwave Irradiation for Effective Antibacterial and Antibiofilm Activities.

    PubMed

    Velusamy, Palaniyandi; Su, Chia-Hung; Venkat Kumar, Govindarajan; Adhikary, Shritama; Pandian, Kannaiyan; Gopinath, Subash C B; Chen, Yeng; Anbu, Periasamy

    2016-01-01

    In the current study, facile synthesis of carboxymethyl cellulose (CMC) and sodium alginate capped silver nanoparticles (AgNPs) was examined using microwave radiation and aniline as a reducing agent. The biopolymer matrix embedded nanoparticles were synthesized under various experimental conditions using different concentrations of biopolymer (0.5, 1, 1.5, 2%), volumes of reducing agent (50, 100, 150 μL), and duration of heat treatment (30 s to 240 s). The synthesized nanoparticles were analyzed by scanning electron microscopy, UV-Vis spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy for identification of AgNPs synthesis, crystal nature, shape, size, and type of capping action. In addition, the significant antibacterial efficacy and antibiofilm activity of biopolymer capped AgNPs were demonstrated against different bacterial strains, Staphylococcus aureus MTCC 740 and Escherichia coli MTCC 9492. These results confirmed the potential for production of biopolymer capped AgNPs grown under microwave irradiation, which can be used for industrial and biomedical applications. PMID:27304672

  15. VUV irradiance measurement of a 2.45 GHz microwave-driven hydrogen discharge

    NASA Astrophysics Data System (ADS)

    Komppula, J.; Tarvainen, O.; Kalvas, T.; Koivisto, H.; Kronholm, R.; Laulainen, J.; Myllyperkiö, P.

    2015-09-01

    Absolute values of VUV-emission of a 2.45 GHz microwave-driven hydrogen discharge are reported. The measurements were performed with a robust and straightforward method based on a photodiode and optical filters. It was found that the volumetric photon emission rate in the VUV-range (80-250 nm) is 1016-1017 cm-3 s-1, which corresponds to approximately 8% dissipation of injected microwave power by VUV photon emission. The volumetric emission of characteristic emission bands was utilized to diagnostics of molecular plasma processes including volumetric rates of ionization, dissociation and excitation to high vibrational levels and metastable states. The estimated reaction rates imply that each injected molecule experiences several inelastic electron impact collisions. The upper limit for the total density of metastable neutrals (2S atoms and {{c}3}{{\\Pi}u} molecules) was estimated to be approximately 0.5% of the neutral gas density.

  16. Microwave-irradiation-assisted hybrid chemical approach for titanium dioxide nanoparticle synthesis: microbial and cytotoxicological evaluation.

    PubMed

    Ranjan, Shivendu; Dasgupta, Nandita; Rajendran, Bhavapriya; Avadhani, Ganesh S; Ramalingam, Chidambaram; Kumar, Ashutosh

    2016-06-01

    Titanium dioxide nanoparticles (TNPs) are widely used in the pharmaceutical and cosmetics industries. It is used for protection against UV exposure due to its light-scattering properties and high refractive index. Though TNPs are increasingly used, the synthesis of TNPs is tedious and time consuming; therefore, in the present study, microwave-assisted hybrid chemical approach was used for TNP synthesis. In the present study, we demonstrated that TNPs can be synthesized only in 2.5 h; however, the commonly used chemical approach using muffle furnace takes 5 h. The activity of TNP depends on the synthetic protocol; therefore, the present study also determined the effect of microwave-assisted hybrid chemical approach synthetic protocol on microbial and cytotoxicity. The results showed that TNP has the best antibacterial activity in decreasing order from Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. The IC50 values of TNP for HCT116 and A549 were found to be 6.43 and 6.04 ppm, respectively. Cell death was also confirmed from trypan blue exclusion assay and membrane integrity loss was observed. Therefore, the study determines that the microwave-assisted hybrid chemical approach is time-saving; hence, this technique can be upgraded from lab scale to industrial scale via pilot plant scale. Moreover, it is necessary to find the mechanism of action at the molecular level to establish the reason for greater bacterial and cytotoxicological toxicity. Graphical abstract A graphical representation of TNP synthesis. PMID:26976013

  17. Evaluation the microwave heating of spinel crystals in high-level waste glass

    SciTech Connect

    Christian, J. H.; Washington, A. L.

    2015-08-18

    In this report, the microwave heating of a crystal-free and a partially (24 wt%) trevorite-crystallized waste glass simulant were evaluated. The results show that a 500 mg piece of partially crystallized waste glass can be heated from room-temperature to above 1600 °C (as measured by infrared radiometry) within 2 minutes using a single mode, highly focused, 2.45 GHz microwave, operating at 300 W. X-ray diffraction measurements show that the partially crystallized glass experiences an 87 % reduction in trevorite following irradiation and thermal quenching. When a crystal-free analogue of the same waste glass simulant composition is exposed to the same microwave radiation it could not be heated above 450 °C regardless of the heating time.

  18. Controlling periodontal bone levels with multiple LED irradiations.

    PubMed

    Chang, Po-Chun; Wang, Chen-Ying; Chong, Li Yen

    2015-02-01

    Because a single exposure to light-emitting diode (LED) irradiation at 660 nm only demonstrated a 3-day biostimulatory effect in recovering periodontal bone level (PBL), this study sought to evaluate whether the periodontal effect could be extended through the use of multiple LED irradiations. Experimental periodontitis was developed unilaterally in 48 Sprague-Dawley rats after the placement of a silk ligature plus Porphyromonas gingivalis lipopolysaccharide injections. The animals were divided into four groups (no irradiation, a single irradiation, or two or three irradiations per week) and exposed to LED light irradiation at a wavelength of 660 ± 25 nm and energy density of 10 J/cm(2) after debridement and detoxification. The animals were euthanized after 7 or 14 days, and the effect of irradiation was evaluated using micro-computed tomography and histology. By day 7, PBL was significantly reduced (p < 0.05), with significantly reduced inflammation (p < 0.05) and gingival hyperplasia (p < 0.001), in the animals receiving three irradiations per week. At day 14, the reduction in gingival hyperplasia was still significant (p < 0.05), and collagen matrix deposition and realignment appeared to be accelerated in the animals receiving three irradiations per week, despite a lack of significant difference in PBL. The treatment regimen receiving three LED light irradiations per week apparently extended the effects in reducing PBL and inflammation to 7 days. The inclusion of additional inflammation control measures or the addition of bioactive signals to mediate the repairing process is necessary to maintain long-term periodontal stability. PMID:23933707

  19. Rapid synthesis and size control of CuInS2 semi-conductor nanoparticles using microwave irradiation

    SciTech Connect

    Gardner, Joseph S.; Shurdha, Endrit; Wang, Chong M.; Lau, Lisa D.; Rodriguez, Rene G.; Pak, Joshua J.

    2008-04-01

    The properties of CuInS2 semi-conductor nanoparticles make them attractive materials for use in next-generation photovoltaics. We have prepared CuInS2 nanoparticles from single source precursors via microwave irradiation. Microwave irradiation methods have allowed us to increase the efficiency of preparation of these materials by providing uniform heating and rapid reaction times. The synergistic effect of varying thiol capping ligand concentrations as well as reaction temperatures and times resulted in fine control of nanoparticle growth in the 3–5 nm size range. Investigation of the photophysical properties of the colloidal nanoparticles were performed using electronic absorption and luminescence emission spectroscopy. Qualitative nanoparticles sizes were determined from the photoluminescence (PLE) data and compared to HRTEM images.

  20. Application of microwave irradiation for the removal of polychlorinated biphenyls from siloxane transformer and hydrocarbon engine oils.

    PubMed

    Antonetti, Claudia; Licursi, Domenico; Raspolli Galletti, Anna Maria; Martinelli, Marco; Tellini, Filippo; Valentini, Giorgio; Gambineri, Francesca

    2016-09-01

    The removal of polychlorinated biphenyls (PCBs) both from siloxane transformer oil and hydrocarbon engine oil was investigated through the application of microwave (MW) irradiation and a reaction system based on polyethyleneglycol (PEG) and potassium hydroxide. The influence of the main reaction parameters (MW irradiation time, molecular weight of PEG, amount of added reactants and temperature) on the dechlorination behavior was studied. Promising performances were reached, allowing about 50% of dechlorination under the best experimental conditions, together time and energy saving compared to conventional heating systems. Moreover, an interesting dechlorination degree (up to 32%) was achieved for siloxane transformer oil when MW irradiation was employed as the unique driving force. To the best of our knowledge, this is the first time in which MW irradiation is tested as the single driving force for the dechlorination of these two types of PCB-contaminated oils. PMID:27281539

  1. Synthesis of solar active nanocrystalline ferrite, MFe 2O 4 (M: Ca, Zn, Mg) photocatalyst by microwave irradiation

    NASA Astrophysics Data System (ADS)

    Dom, Rekha; Subasri, R.; Radha, K.; Borse, Pramod H.

    2011-03-01

    For the first time, nanocrystalline photocatalysts of spinel MgFe2O4, ZnFe2O4 and orthorhombic CaFe2O4 oxides were synthesized (at low temperature ˜973 K) by microwave sintering, in one sixtieth of the time required to that of the conventional method. A significantly improved crystallinity was obtained for the samples irradiated for longer duration of time (˜10-100 min). The theoretically computed electronic structure of the MFe2O4 (M: Ca, Zn, Mg) systems was respectively correlated with the experimental results obtained from their structural and photocatalytic characterization. The photocatalytic performance was found to be affected by surface area and crystallinity of the photocatalyst. The density functional theory (DFT) calculations of MFe2O4 lattices revealed that M-ion controllably affects the density of sates of the Fe-d orbitals near the Fermi level. Consequently they play an important role in determining the band-energetics and thus the visible light photocatalytic activity for methylene blue degradation.

  2. Rapid preparation of expanded graphite by microwave irradiation for the extraction of triazine herbicides in milk samples.

    PubMed

    Zhang, Fengshuang; Zhao, Qi; Yan, Xu; Li, Huiyu; Zhang, Ping; Wang, Long; Zhou, Tianyu; Li, Yi; Ding, Lan

    2016-04-15

    In this study, we proposed a rapid and efficient method for the preparation of the expanded graphite (EG). The exfoliation process was accelerated by microwave irradiation, and the preparation time was greatly shortened. The obtained EG was worm-like in shape and exhibits well exfoliated structure. It was successfully applied as solid-phase extraction (SPE) adsorbent to extract and clean up the triazine herbicides in milk, followed by liquid chromatography tandem mass spectrometry (LC-MS) analysis. The parameters affecting the performance of extraction and LC-MS analysis were evaluated. Under the optimal conditions, the detection limits of triazines are in the range of 0.03-0.12 ng mL(-1). At the spiked level (0.4 ng mL(-1)), the recoveries of triazines are in the range of 82.5±2.5% to 97.5±7.5%. The proposed method was successfully applied to determine six triazines in six milk samples. PMID:26617038

  3. Microwave irradiation for shortening the processing time of samples of flagellated bacteria for scanning electron microscopy.

    PubMed

    Hernández-Chavarría, Francisco

    2004-01-01

    Microwave irradiation (MWI) has been applied to the development of rapid methods to process biological samples for scanning electron microscopy (SEM). In this paper we propose two simple and quick techniques for processing bacteria (Proteus mirabilis and Vibrio mimicus) for SEM using MWI. In the simplest methodology, the bacteria were placed on a cover-glass, air-dried, and submitted to conductivity stain. The reagent used for the conductivity stain was the mordant of a light microscopy staining method (10 ml of 5% carbolic acid solution, 2 g of tannic acid, and 10 ml of saturated aluminum sulfate 12-H2O). In the second method the samples were double fixed (glutaraldehyde and then osmium), submitted to conductivity stain, dehydrated through a series of ethanol solutions of increasing concentration, treated with hexamethyldisilazine (HMDS), and dried at 35 degrees C for 5 minutes. In both methods the steps from fixation to treatment with HMDS were done under MWI for 2 minutes in an ice-water bath, in order to dissipate the heat generated by the MWI. Although both techniques preserve bacterial morphology adequately, the latter, technique showed the best preservation, including the appearance of flagella, and that process was completed in less than 2 hours at temperatures of MWI between 4 to 5 degrees C. PMID:17061527

  4. Regioselective synthesis and ab initio calculations of fused heterocycles thermally and under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Salem, Mostafa E.; Ahmed, Ashour A.; Shaaban, Mohamed R.; Shibl, Mohamed F.; Farag, Ahmad M.

    2015-09-01

    Pyrazolo[1,5-a]pyrimidine, triazolo[1,5-a]pyrimidine, and pyrimido[1,2-a]benzimidazole, pyrido[1,2-a]benzimidazole ring systems incorporating phenylsulfonyl moiety were synthesized via the reaction of 3-(N,N-dimethylamino)-1-(thiophen-2-yl)-2-(phenylsulfonyl)prop-2-en-1-one derivatives with the appropriate aminoazoles as 1,3-binucleophiles and 1H-benzimidazol-2-ylacetonitrile using conventional methods as well as microwave irradiation. The regioselectivity of the cyclocondensation reactions was confirmed both experimentally by alternative synthesis of reaction products and theoretically using ab initio quantum chemical calculations namely the Density Functional Theory (DFT). The theoretical work was carried out using the Becke, three parameter, Lee-Yang-Parr hybrid functional (B3LYP) combined with the 6-311++G(d,p) basis set. It was found that the final cyclocondensation reaction product depends mainly on the initial addition to the activated double bond by the nitrogen atom of the 1,3-binucleophiles that has the higher electron density.

  5. An approach of ionic liquids/lithium salts based microwave irradiation pretreatment followed by ultrasound-microwave synergistic extraction for two coumarins preparation from Cortex fraxini.

    PubMed

    Liu, Zaizhi; Gu, Huiyan; Yang, Lei

    2015-10-23

    Ionic liquids/lithium salts solvent system was successfully introduced into the separation technique for the preparation of two coumarins (aesculin and aesculetin) from Cortex fraxini. Ionic liquids/lithium salts based microwave irradiation pretreatment followed by ultrasound-microwave synergy extraction (ILSMP-UMSE) procedure was developed and optimized for the sufficient extraction of these two analytes. Several variables which can potentially influence the extraction yields, including pretreatment time and temperature, [C4mim]Br concentration, LiAc content, ultrasound-microwave synergy extraction (UMSE) time, liquid-solid ratio, and UMSE power were optimized by Plackett-Burman design. Among seven variables, UMSE time, liquid-solid ratio, and UMSE power were the statistically significant variables and these three factors were further optimized by Box-Behnken design to predict optimal extraction conditions and find out operability ranges with maximum extraction yields. Under optimum operating conditions, ILSMP-UMSE showed higher extraction yields of two target compounds than those obtained by reference extraction solvents. Method validation studies also evidenced that ILSMP-UMSE is credible for the preparation of two coumarins from Cortex fraxini. This study is indicative of the proposed procedure that has huge application prospects for the preparation of natural products from plant materials. PMID:26411478

  6. Zero-resistance states in Hall bars at low microwave frequency irradiation

    SciTech Connect

    Iñarrea, J.

    2013-12-04

    We report on theoretical studies of recently discovered radiation-induced resistance oscillations and zero resistance states in Hall bars when the irradiation frequency is very low. In this situation the photon energy is much smaller than the spacing between the Landau levels and therefore interlevel transitions are excluded. We apply the radiation-driven electron orbit model concluding that the resistance suppression is a manifestation of “long-wavelength” resistance oscillations where only one complete oscillation is observed.

  7. Estimation of Radiofrequency Power Leakage from Microwave Ovens for Dosimetric Assessment at Nonionizing Radiation Exposure Levels

    PubMed Central

    Lopez-Iturri, Peio; de Miguel-Bilbao, Silvia; Aguirre, Erik; Azpilicueta, Leire; Falcone, Francisco; Ramos, Victoria

    2015-01-01

    The electromagnetic field leakage levels of nonionizing radiation from a microwave oven have been estimated within a complex indoor scenario. By employing a hybrid simulation technique, based on coupling full wave simulation with an in-house developed deterministic 3D ray launching code, estimations of the observed electric field values can be obtained for the complete indoor scenario. The microwave oven can be modeled as a time- and frequency-dependent radiating source, in which leakage, basically from the microwave oven door, is propagated along the complete indoor scenario interacting with all of the elements present in it. This method can be of aid in order to assess the impact of such devices on expected exposure levels, allowing adequate minimization strategies such as optimal location to be applied. PMID:25705676

  8. Estimation of radiofrequency power leakage from microwave ovens for dosimetric assessment at nonionizing radiation exposure levels.

    PubMed

    Lopez-Iturri, Peio; de Miguel-Bilbao, Silvia; Aguirre, Erik; Azpilicueta, Leire; Falcone, Francisco; Ramos, Victoria

    2015-01-01

    The electromagnetic field leakage levels of nonionizing radiation from a microwave oven have been estimated within a complex indoor scenario. By employing a hybrid simulation technique, based on coupling full wave simulation with an in-house developed deterministic 3D ray launching code, estimations of the observed electric field values can be obtained for the complete indoor scenario. The microwave oven can be modeled as a time- and frequency-dependent radiating source, in which leakage, basically from the microwave oven door, is propagated along the complete indoor scenario interacting with all of the elements present in it. This method can be of aid in order to assess the impact of such devices on expected exposure levels, allowing adequate minimization strategies such as optimal location to be applied. PMID:25705676

  9. Target detection using microwave irradiances from natural sources: A passive, local and global surveillance system

    NASA Astrophysics Data System (ADS)

    Stacey, J. M.

    1984-11-01

    Detection of metal objects on or near the Earth's surface was investigated using existing, passive, microwave sensors operating from Earth orbit. The range equations are derived from basic microwave principles and theories and the expressions are given explicitly to estimate the signal to noise ratio for detecting metal targets operating as bistatic scatterers. Actual measurements are made on a range of metal objects observed from orbit using existing passive microwave receiving systems. The details of the measurements and the results are tabulated and discussed. The advantages of a passive microwave sensor as it is applied to surveillance of metal objects as viewed from aerial platforms or from orbit, are examined.

  10. Photolysis of low concentration H2S under UV/VUV irradiation emitted from microwave discharge electrodeless lamps.

    PubMed

    Xia, Lan-Yan; Gu, Ding-Hong; Tan, Jing; Dong, Wen-Bo; Hou, Hui-Qi

    2008-04-01

    The photolysis of simulating low concentration of hydrogen sulfide malodorous gas was studied under UV irradiation emitted by self-made microwave discharge electrodeless lamps (i.e. microwave UV electrodeless mercury lamp (185/253.7 nm) and iodine lamp (178.3/180.1/183/184.4/187.6/206.2 nm)). Experiments results showed that the removal efficiency (eta H2S) of hydrogen sulfide was decreased with increasing initial H2S concentration and increased slightly with gas residence time; H2S removal efficiency was decreased dramatically with enlarged pipe diameter. Under the experimental conditions with pipe diameter of 36 mm, gas flow rate of 0.42 standard l s(-1), eta H2S was 52% with initial H2S concentration of 19.5 mg m(-3) by microwave mercury lamp, the absolute removal amount (ARA) was 4.30 microg s(-1), and energy yield (EY) was 77.3 mg kW h(-1); eta H2S was 56% with initial H2S concentration of 18.9 mg m(-3) by microwave iodine lamp, the ARA was 4.48 microg s(-1), and the EY was 80.5mg kW h(-1). The main photolysis product was confirmed to be SO4(2-) with IC. PMID:18334265

  11. Development of a Backbone Cyclic Peptide Library as Potential Antiparasitic Therapeutics Using Microwave Irradiation.

    PubMed

    Qvit, Nir; Kornfeld, Opher S

    2016-01-01

    Protein-protein interactions (PPIs) are intimately involved in almost all biological processes and are linked to many human diseases. Therefore, there is a major effort to target PPIs in basic research and in the pharmaceutical industry. Protein-protein interfaces are usually large, flat, and often lack pockets, complicating the discovery of small molecules that target such sites. Alternative targeting approaches using antibodies have limitations due to poor oral bioavailability, low cell-permeability, and production inefficiency. Using peptides to target PPI interfaces has several advantages. Peptides have higher conformational flexibility, increased selectivity, and are generally inexpensive. However, peptides have their own limitations including poor stability and inefficiency crossing cell membranes. To overcome such limitations, peptide cyclization can be performed. Cyclization has been demonstrated to improve peptide selectivity, metabolic stability, and bioavailability. However, predicting the bioactive conformation of a cyclic peptide is not trivial. To overcome this challenge, one attractive approach it to screen a focused library to screen in which all backbone cyclic peptides have the same primary sequence, but differ in parameters that influence their conformation, such as ring size and position. We describe a detailed protocol for synthesizing a library of backbone cyclic peptides targeting specific parasite PPIs. Using a rational design approach, we developed peptides derived from the scaffold protein Leishmania receptor for activated C-kinase (LACK). We hypothesized that sequences in LACK that are conserved in parasites, but not in the mammalian host homolog, may represent interaction sites for proteins that are critical for the parasites' viability. The cyclic peptides were synthesized using microwave irradiation to reduce reaction times and increase efficiency. Developing a library of backbone cyclic peptides with different ring sizes facilitates a

  12. Ultrafast in vivo microwave irradiation for enhanced metabolic stability of brain biopsy samples during HRMAS NMR analysis.

    PubMed

    Detour, J; Elbayed, K; Piotto, M; Moussallieh, F M; Nehlig, A; Namer, I J

    2011-09-30

    High resolution magic-angle spinning (HRMAS) NMR spectroscopy is a well established technique for ex vivo metabolite investigations but experimental factors such as ischemic delay or mechanical stress due to continuous spinning deserve further investigations. Cortical brain samples from rats that underwent ultrafast in vivo microwave irradiation (MWp group) were compared to similar samples that underwent standard nitrogen freezing with and without exposure to domestic microwaves (FN and FN+MWd groups). One dimensional (1)H HRMAS NMR spectra were acquired and 16 metabolites of interest were quantified. Within each group 3 samples underwent long lasting acquisition (up to 15 h). Statistically significant differences in metabolite concentrations were observed between groups for metabolites associated to post mortem biochemical changes and/or anaerobic glycolysis including several neurotransmitters. Spectral assessment over time showed a drastic reduction of biochemical variations in both MW groups. Only 2/16 metabolites exhibited significant signal variations after 15 h of continuous spinning and acquisition in the MWp group. This number increased to 10 in the FN group. We confirmed limited anaerobic metabolism and post mortem degradation after ultra fast in vivo MW irradiation. Furthermore, spectra obtained after MWp and MWd irradiation exhibited an extremely stable spectral pattern over extended periods of continuous acquisition. PMID:21803072

  13. Influences of doping Cr/Fe/Ta on the performance of Ni/CeO2 catalyst under microwave irradiation in dry reforming of CH4

    NASA Astrophysics Data System (ADS)

    Odedairo, Taiwo; Ma, Jun; Chen, Jiuling; Wang, Shaobin; Zhu, Zhonghua

    2016-01-01

    The structure of Ni/CeO2 catalyst with doping of Cr, Fe and Ta was investigated with XRD, N2 physisorption, XPS and HRTEM and the catalytic activity of the catalysts under microwave irradiation in dry reforming of methane was tested in a microwave reactor. The results show that the introduction of Cr and Ta to Ni/CeO2 can enhance the interaction between Ni and the support/promoter and inhibit the enlargement of NiO particles during the synthesis. The CH4 conversions in dry reforming on the catalysts follow the order: Ni/CeO2<2Fe-Ni<2Ta-Ni<2Cr-Ni. The superior performance of 2Ta-Ni and 2Cr-Ni may be attributed to the locally-heated Ni particles caused by the strong microwave absorption of the in-situ grown graphene attached on them under microwave irradiation.

  14. Dynamic microstructures and fractal characterization of cell wall disruption for microwave irradiation-assisted lipid extraction from wet microalgae.

    PubMed

    Cheng, Jun; Sun, Jing; Huang, Yun; Feng, Jia; Zhou, Junhu; Cen, Kefa

    2013-12-01

    To extract lipids from wet microalgae through cell disruption, the effects of microwave treatment on the dynamic cell wall microstructures were investigated. The fractal dimension of raw, untreated microalgal cells was 1.46. The disruption level of microalgal cell walls was enhanced when microwave treatment temperature increased from 80 to 120°C, resulting in an increase in microalgal cell fractal dimension from 1.61 to 1.91. The cell wall thickness and pore diameters in cell walls increased from 0.11 to 0.59 μm and from 0.005 to 0.18 μm, respectively, when microwave treatment time increased from 0 to 20 min. The outer pectin layers of cell walls gradually detached and the porosity of inner cellulose layers increased when microwave treatment time increased to 26 min. The initial point of disruption appeared at the maximum curvature (approximately 1.01×10(7) m(-1)) of cell walls. Numbers of short-chain and saturated lipids increased because of microwave electromagnetic effect. PMID:24152788

  15. PROCESS INTENSIFICATION: OXIDATION OF BENZYL ALCOHOL USING A CONTINUOUS ISOTHERMAL REACTOR UNDER MICROWAVE IRRADIATION

    EPA Science Inventory

    In the past two decades, several investigations have been carried out using microwave radiation for performing chemical transformations. These transformations have been largely performed in conventional batch reactors with limited mixing and heat transfer capabilities. The reacti...

  16. Morphological control and evolution of octahedral and truncated trisoctahedral Pt-Au alloy nanocrystals under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Dai, Lei; Zhao, Yanxi; Chi, Quan; Liu, Hanfan; Li, Jinlin; Huang, Tao

    2014-08-01

    Uniform and well-defined truncated trisoctahedral and octahedral Pt-Au alloy nanocrystals were fabricated by co-reducing H2PtCl6-HAuCl4 with tetraethylene glycol (TEG) under microwave irradiation for only 140 s. Iodide ions were critical to the morphological control and evolution of Pt-Au alloy nanostructures. The as-prepared Pt-Au alloy nanocrystals exhibited efficient electrocatalytic activities.Uniform and well-defined truncated trisoctahedral and octahedral Pt-Au alloy nanocrystals were fabricated by co-reducing H2PtCl6-HAuCl4 with tetraethylene glycol (TEG) under microwave irradiation for only 140 s. Iodide ions were critical to the morphological control and evolution of Pt-Au alloy nanostructures. The as-prepared Pt-Au alloy nanocrystals exhibited efficient electrocatalytic activities. Electronic supplementary information (ESI) available: Experimental details; SEM, TEM and HAADF-STEM images, UV-vis absorbance spectra, XRD. See DOI: 10.1039/c4nr01864h

  17. Facile synthesis of lead iodide nanostructures by microwave irradiation technique and their structural, morphological, photoluminescence and dielectric studies

    NASA Astrophysics Data System (ADS)

    Shkir, Mohd.; Yahia, I. S.; AlFaify, S.; Abutalib, M. M.; Muhammad, Shabbir

    2016-04-01

    Lead iodide (PbI2) nanostructures have been synthesized by co-precipitation, hydrothermal and rapidly by microwave irradiation techniques. SEM analysis indicated the formation of well aligned nanocrystals and nanorods of average diameter between 100 nm and 400 nm. The powder X-ray diffraction and FT-Raman spectroscopic analysis confirms the formation of a 2H-PbI2 polytypic predominantly. These studies also show that there is no extra phase due to impurity in the synthesized nanostructures. The optical energy band gap of nanostructures prepared by co-precipitation, hydrothermal and microwave irradiation techniques were found to be 2.283, 2.493, 2.542 eV and 2.331. 2.350, 2.375 eV calculated from UV-Vis absorption and diffuse reflectance data, respectively, which shows a clear blue shift in the wavelength due to confinement effect. Photoluminescence spectrum was recorded at different excitation wavelengths and shows clear blue shift in the emission peak which is due to the recombination of free excitons with band to band type transition and also may be due to confinement effect. Further the dielectric studies have been performed and a good enhancement in the dielectric constant has been observed due to small size of the fabricated nanostructures in comparison to bulk material.

  18. Effects of dehulling, steam-cooking and microwave-irradiation on digestive value of white lupin (Lupinus albus) seed meal for rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar).

    PubMed

    Saez, Patricio; Borquez, Aliro; Dantagnan, Patricio; Hernández, Adrián

    2015-01-01

    A digestibility trial was conducted to assess the effect of dehulling, steam-cooking and microwave-irradiation on the apparent digestibility of nutrients in white lupin (Lupinus albus) seed meal when fed to rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). Six ingredients, whole lupin seed meal (LSM), dehulled LSM, dehulled LSM steam-cooked for 15 or 45 min (SC15 and SC45, respectively) and LSM microwave-irradiated at 375 or 750 W (MW375 and MW750, respectively), were evaluated for digestibility of dry matter, crude protein (CP), lipids, nitrogen-free extractives (NFE) and gross energy (GE). The diet-substitution approach was used (70% reference diet + 30% test ingredient). Faeces from each tank were collected using a settlement column. Dehulled LSM showed higher levels of proximate components (except for NFE and crude fibre), GE and phosphorus in comparison to whole LSM. Furthermore, SC15, SC45, MW375 and MW750 showed slight variations of chemical composition in comparison to dehulled LSM. Results from the digestibility trial indicated that dehulled LSM, SC15, SC45 and MW375 are suitable processing methods for the improvement of nutrients' apparent digestibility coefficient (ADC) in whole LSM. MW750 showed a lower ADC of nutrients (except for CP and lipids for rainbow trout) in comparison with MW350 for rainbow trout and Atlantic salmon, suggesting a heat damage of the ingredient when microwave-irradiation exceeded 350 W. PMID:25708530

  19. Effect of different fat level on microwave cooking properties of goat meat patties.

    PubMed

    Das, Arun K; Rajkumar, V

    2013-12-01

    The study was carried out to evaluate the effect of various fat levels on the cooking and sensory properties of goat meat patties cooked by microwave energy. Goat meat patties were prepared with refined vegetable oil to get fat level of 5, 10, 15 and 20%. Each patty was cooked in a microwave oven with full power (700 W) operating at 2450 MHz to an internal temperature of 75-80 °C. pH value of raw patties with 5% fat level were lower compared to patties with 10, 15 and 20% fat level. Fat level did not affect emulsion stability of batter but it decreased as fat level increased. Microwave cooking time decreased as fat levels increased. With an increase in fat contents, protein and moisture in raw patties decreased and in cooked meat patties with 5% fat had higher protein and moisture content than those with more fat. Patties with 5% level showed lower cooking loss than other fat level. Water activity of patties was affected by fat level and patties with 15 and 20% fat had lower water activity than patties with 5 and 10% fat. As fat level increased, shear force value decreased indicating soft texture. Subjective colour evaluation indicated that 5% patties were darker and redder than patties with more fat. Sensory analysis revealed that goat meat patties with 5 and 10% fat had less flavour and juicer than patties with 15 and 20% fat. Goat meat patties with 20% fat were the juiciest. Tenderness and oiliness increased significantly with an increase in fat level. Patties with 15% fat were rated higher overall palatability than others. PMID:24426036

  20. The Quality Characteristics of Salted Ground Pork Patties Containing Various Fat Levels by Microwave Cooking.

    PubMed

    Jeong, Jong Youn; Lim, Seung Taek; Kim, Cheon Jei

    2016-01-01

    This study was carried out to evaluate the effects of fat level on the microwave cooking properties of ground pork patties with NaCl (1.5%). Ground pork patties were processed from pork hams to achieve fat levels of 10%, 15%, 20%, and 25%, respectively. Each patty was cooked from a thawed state to 75℃ in a microwave oven at full power (700 W). After microwave cooking, protein content, moisture content, fat retention, and shear force values in patties decreased as fat level increased from 10 to 25%. As fat level increased, cooking time decreased but total cooking loss and drip loss were increased, whereas slight differences in diameter reduction and thickness of patties were observed. In raw patties, 10% fat patties had lower L* values and higher a* values compared to patties with more fat, but these differences were reduced when patties were cooked. Patties with 10% fat showed a more pink color on the surface and interior than patties with a higher fat content but more air pockets were noted in higher-fat patties. Higher-fat patties were more tender, juicy, and oily than lower-fat patties. PMID:27621696

  1. The Quality Characteristics of Salted Ground Pork Patties Containing Various Fat Levels by Microwave Cooking

    PubMed Central

    Jeong, Jong Youn; Lim, Seung Taek; Kim, Cheon Jei

    2016-01-01

    This study was carried out to evaluate the effects of fat level on the microwave cooking properties of ground pork patties with NaCl (1.5%). Ground pork patties were processed from pork hams to achieve fat levels of 10%, 15%, 20%, and 25%, respectively. Each patty was cooked from a thawed state to 75℃ in a microwave oven at full power (700 W). After microwave cooking, protein content, moisture content, fat retention, and shear force values in patties decreased as fat level increased from 10 to 25%. As fat level increased, cooking time decreased but total cooking loss and drip loss were increased, whereas slight differences in diameter reduction and thickness of patties were observed. In raw patties, 10% fat patties had lower L* values and higher a* values compared to patties with more fat, but these differences were reduced when patties were cooked. Patties with 10% fat showed a more pink color on the surface and interior than patties with a higher fat content but more air pockets were noted in higher-fat patties. Higher-fat patties were more tender, juicy, and oily than lower-fat patties. PMID:27621696

  2. Microwave power transmission system wherein level of transmitted power is controlled by reflections from receiver

    NASA Technical Reports Server (NTRS)

    Robinson, W. J., Jr. (Inventor)

    1974-01-01

    A microwave, wireless, power transmission system is described in which the transmitted power level is adjusted to correspond with power required at a remote receiving station. Deviations in power load produce an antenna impedance mismatch causing variations in energy reflected by the power receiving antenna employed by the receiving station. The variations in reflected energy are sensed by a receiving antenna at the transmitting station and used to control the output power of a power transmitter.

  3. Separation of ZnO from the Stainless Steelmaking Dust and Graphite Mixture by Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Zhou, Yun; Wu, Liushun; Wang, Jue; Wang, Haichuan; Dong, Yuanchi

    2015-04-01

    In this study, microwave was used to treat stainless steelmaking dust containing zinc oxide. The effects of heating time, carbon content and zinc oxide content on the removal efficiency of zinc oxide and the reduction efficiency of iron oxide were investigated. Experimental results show that, for the sample with 16% (mass percent, the same below) graphite heated for 10 minutes by 10 kW power microwave, the removal efficiency of zinc oxide is between 80% and 90% and the metallization ratio of iron oxide is between 40% and 60%; Initial zinc oxide content has a slight effect on the removal efficiency of zinc oxide. The results indicate microwave treatment is one of the feasible ways to process metallurgical solid waste containing the metal with low boiling point.

  4. Rapid and Efficient Functionalized Ionic Liquid-Catalyzed Aldol Condensation Reactions Associated with Microwave Irradiation

    PubMed Central

    Wang, Chang; Liu, Jing; Leng, Wenguang; Gao, Yanan

    2014-01-01

    Five quaternary ammonium ionic liquid (IL) and two tetrabutylphosphonium ILs were prepared and characterized. An environmentally benign and convenient functionalized ionic liquid catalytic system was thus explored in the aldol condensation reactions of aromatic aldehydes with acetone. The aldol reactions proceeded more efficiently through microwave-assisted heating than through conventional thermal heating. The yield of products obtained under microwave heating for 30 min was approximately 90%, and the ILs can be recovered and reused at least five times without apparent loss of activity. In addition, this catalytic system can be successfully extended to the Henry reactions. PMID:24445262

  5. Synergetic pretreatment of sewage sludge by microwave irradiation in presence of H2O2 for enhanced anaerobic digestion.

    PubMed

    Eskicioglu, Cigdem; Prorot, Audrey; Marin, Juan; Droste, Ronald L; Kennedy, Kevin J

    2008-11-01

    A microwave-enhanced advanced hydrogen peroxide oxidation process (MW/H(2)O(2)-AOP) was studied in order to investigate the synergetic effects of MW irradiation on H(2)O(2) treated waste activated sludges (WAS) in terms of mineralization (permanent stabilization), sludge disintegration/solubilization, and subsequent anaerobic biodegradation as well as dewaterability after digestion. Thickened WAS sample pretreated with 1gH(2)O(2)/g total solids (TS) lost 11-34% of its TS, total chemical oxygen demand (COD) and total biopolymers (humic acids, proteins and sugars) via advanced oxidation. In a temperature range of 60-120 degrees C, elevated MW temperatures (>80 degrees C) further increased the decomposition of H(2)O(2) into OH* radicals and enhanced both oxidation of COD and solubilization of particulate COD (>0.45 micron) of WAS indicating that a synergetic effect was observed when both H(2)O(2) and MW treatments were combined. However, at all temperatures tested, MW/H(2)O(2) treated samples had lower first-order mesophilic (33+/-2 degrees C) biodegradation rate constants and ultimate (after 32 days of digestion) methane yields (mL per gram sample) compared to control and MW irradiated WAS samples, indicating that synergistically (MW/H(2)O(2)-AOP) generated soluble organics were slower to biodegrade or more refractory than those generated during MW irradiation. PMID:18783812

  6. MICROWAVE IRRADIATION IN BENIGN SYNTHESIS OF ORGANIC MOLECULES, NOBLE NANOMETALS AND NANOCOMPOSITES

    EPA Science Inventory

    A brief historic account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds [1] from in situ generated reacti...

  7. MICROWAVE IRRADIATION IN BENIGN SYNTHESIS OF HETEROCYCLES, NOBLE NANOMETALS AND NANOCOMPOSITES

    EPA Science Inventory

    A brief historic account of reactions involving microwave (MW) exposure of neat reactants or catalyzed by mineral support surfaces, such as alumina, silica, clay, or their ‘doped’ versions, for the rapid one-pot assembly of heterocyclic compounds [1] from in situ generated reacti...

  8. GREENER ORGANIC SYNTHESES UNDER NON-TRADITIONAL CONDITIONS USING MICROWAVE AND ULTRASOUND IRRADIATION AND MECHANOCHEMICAL MIXING

    EPA Science Inventory

    Solvent-free mechanochemical methods that involve the use of hypervalent iodine reagents at room temperature are described for the synthesis of heterocyclic entities and conversion of ketones into -keto sulfones in high yields. A solvent-free approach that involves microwave (MW...

  9. SOLVENT-FREE REDUCTION OF AROMATIC NITRO COMPOUNDS WITH ALUMINA-SUPPORTED HYDRAZINE UNDER MICROWAVE IRRADIATION

    EPA Science Inventory

    In a solvent-free microwave-expedited process, aromatic nitro compounds are readily reduced to the corresponding amino compounds in good yield with hydrazine hydrate supported on alumina in presence of FeCl3, 6H2), Fe(III) oxide hydroxide or Fe(III) oxides.

  10. ‘Greener’ Chemical Syntheses Using Mechanochemical Mixing or Microwave and Ultrasound Irradiation

    EPA Science Inventory

    Various emerging ‘greener’ strategic pathways researched primarily in the author’s own laboratory are summarized. They include solvent-free mechanochemical methods and microwave (MW) exposure of neat reactants (undiluted) catalyzed by the surfaces of less-expensive and recyclabl...

  11. Rapid conversion of sorbitol to isosorbide in hydrophobic ionic liquids under microwave irradiation.

    PubMed

    Kamimura, Akio; Murata, Kengo; Tanaka, Yoshiki; Okagawa, Tomoki; Matsumoto, Hiroshi; Kaiso, Kouji; Yoshimoto, Makoto

    2014-12-01

    Sorbitol was effectively converted to isosorbide by treatment with [TMPA][NTf2 ] in the presence of catalytic amounts of TsOH under microwave heating at 180 °C. The reaction completed within 10 min and isosorbide was isolated to about 60%. Ionic liquids were readily recovered by an extraction treatment and reused several times. PMID:25223397

  12. Assessment of cochlear damage after microwave irradiation. Final report, 30 September 1985-17 February 1988

    SciTech Connect

    Bohne, B.A.; Gruner, M.M.; Bassen, H.I.

    1988-02-26

    The objective of this project was to determine whether or not excessive exposure to microwaves results in permanent damage to the inner ear. A group of 15 chinchillas was exposed for one hour to pulsed microwaves (1250 MHz) of 20 usec duration and 0.1-Hz repetition rate and an average power of 1 Watt. The specific absorption rate of various measurement sites in the head ranged from 2-8 Wkg. The exposures were done at the WRAIR Microwave Laboratory, Washington, D.C. Seven animals were sham-exposed for one hour using the same apparatus and sedation. For the sham exposures, the microwave equipment was powered but no radiation was delivered. The cochleas from 20 control chinchillas of the same age range as the animals in the study were available for comparison purposes. The controls had spent their entire lives in sound-treated animal quarters at Washington University in St. Louis, MO. The cochleas from all animals were processed for histological evaluation as plastic-embedded flat preparations. Some animals were processed less than 24 hour after their exposures; the rest were processed after a month or more of recovery. In each cochlea, the following quantitative data were obtained: the extent and pattern of degeneration in the sensory-cell populations; the number of missing pillar cells; the extent and location of degeneration of the stria vascularis and of the myelinated nerve fibers in the osseous spiral lamina.

  13. BULK SYNTHESIS OF SILVER NANORODS IN POLY(ETHYLENE GLYCOL) USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Microwave-assisted (MW), surfactantless, greener approach to bulk synthesis of silver nanorods employing poly (ethylene glycol) (PEG) is described. An aqueous solution of silver nitrate (AgNO-3,- 0.1 M, 4 mL) and 4 mL of PEG (molecular weight 300) were mixed at room temperature t...

  14. Expeditious synthesis of noble metal nanoparticles using Vitamin B12 under microwave irradiation

    EPA Science Inventory

    A greener synthesis protocol for noble nanometals is developed using vitamin B12 as a reducing and capping agent in conjunction with the use of microwaves. Successful assembly of nanoparticles or microparticles with varied shapes and sizes have been demonstrated. The synthesized ...

  15. EFFECT OF POLY (ETHYLENE GLYCOL) ON THE FORMATION OF NANOSTRUCTURES: A FACILE SUSTAINABLE APPROACH FOR THE SYNTHESIS OF SILVER NANORODS USING MICROWAVE IRRADIATION

    EPA Science Inventory

    Bulk synthesis of silver nanorods employing poly (ethylene glycol) (PEG) under microwave irradiation is reported. The formation of nanorods or particulate morphology is dependent on the PEG concentration. This greener method uses no surfactants or reducing agents and employs a b...

  16. PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF SUPERCRITICAL CARBON DIOXIDE-TREATED AND AIR-CLASSIFIED OAT BRAN CONCENTRATE MICROWAVE-IRRADIATED IN WATER OR ETHANOL AT VARYING TEMPERATURES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oat bran concentrate (OBC) was defatted with supercritical carbon dioxide (SCD), then microwave-irradiated at 50, 100 or 150 deg C for 10 min in water, 50% or 100% ethanol, and extract pH, soluble solids, phenolic content and antioxidant activity were analyzed. OBC was air-classified into five frac...

  17. Total synthesis of protosappanin A and its derivatives via palladium catalyzed ortho C-H activation/C-C cyclization under microwave irradiation.

    PubMed

    Liu, Jiaqi; Zhou, Xuan; Wang, Chenglong; Fu, Wanyong; Chu, Wenyi; Sun, Zhizhong

    2016-04-14

    A total synthesis method for protosappanin A, which is a complex natural product with many biological activities, was developed with 6 linear steps. Dibenzo[b,d]oxepinones as the key intermediates of the synthetic route were prepared by a palladium-catalyzed ortho C-H activation/C-C cyclization under microwave irradiation. 25 derivatives of protosappanin A were obtained. PMID:26997503

  18. Soil microbial biomass carbon measurement using microwave irradiation: effects of soil water content, texture and temperature on microbial cell kill and C release

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fumigation-based methods of soil microbial biomass carbon (C) have been replaced in many labs by microwave (MW) irradiation-based methods to reduce hazardous chemical use. Sine the introduction of the MW method concerns have been raised about the use of water filled porosity (WFP) for water content...

  19. Elevation of serum 25-hydroxycalciferol levels in androgen-treated and ultraviolet-irradiated rats.

    PubMed

    Ohata, M; Sakagami, Y; Fujita, T

    1977-10-01

    Administration of 4-8 mg testosterone propionate significantly raised 25-hydroxycalciferol levels in the ultraviolet irradiated rats compared to the ultraviolet irradiated controls, but failed to influence serum 25-hydroxycalciferol levels in the non-irradiated animals. Estradiol benzoate and progesterone did not influence serum 25-hydroxycalciferol levels regardless of the ultraviolet irradiation. These findings implicate that testosterone enhances vitamin D biosynthesis induced by ultraviolet irradiation in rats, in accordance with the clinical observation that males often show higher levels of serum 25-hydroxycalciferol than females. PMID:303993

  20. Proton irradiation effects on advanced digital and microwave III-V components

    SciTech Connect

    Hash, G.L.; Schwank, J.R.; Shaneyfelt, M.R.; Sandoval, C.E.; Connors, M.P.; Sheridan, T.J.; Sexton, F.W.; Slayton, E.M.; Heise, J.A.; Foster, C.

    1994-09-01

    A wide range of advanced III-V components suitable for use in high-speed satellite communication systems were evaluated for displacement damage and single-event effects in high-energy, high-fluence proton environments. Transistors and integrated circuits (both digital and MMIC) were irradiated with protons at energies from 41 to 197 MeV and at fluences from 10{sup 10} to 2 {times} 10{sup 14} protons/cm{sup 2}. Large soft-error rates were measured for digital GaAs MESFET (3 {times} 10{sup {minus}5} errors/bit-day) and heterojunction bipolar circuits (10{sup {minus}5} errors/bit-day). No transient signals were detected from MMIC circuits. The largest degradation in transistor response caused by displacement damage was observed for 1.0-{mu}m depletion- and enhancement-mode MESFET transistors. Shorter gate length MESFET transistors and HEMT transistors exhibited less displacement-induced damage. These results show that memory-intensive GaAs digital circuits may result in significant system degradation due to single-event upset in natural and man-made space environments. However, displacement damage effects should not be a limiting factor for fluence levels up to 10{sup 14} protons/cm{sup 2} [equivalent to total doses in excess of 10 Mrad(GaAs)].

  1. Rapid photocatalytic destruction of pentachlorophenol in F-Si-comodified TiO(2) suspensions under microwave irradiation.

    PubMed

    Yang, Shaogui; Fu, Hongbo; Sun, Cheng; Gao, Zhanqi

    2009-01-30

    A novel photocatalysis material, F-Si-comodified TiO(2) (FST) powder, was synthesized by ultrasound-assisted hydrolysis. The prepared material was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-visible absorption spectroscopy, respectively. XRD analysis indicated that the phase of FST was pure anatase and Si atoms suppressed the growth of titania crystalline, XPS spectra showed that FST was composed of Ti, O, Si and F element, the band gap energy of FST calculated according to the spectrum of UV-vis absorption was 3.26 eV. The electron spin resonance (ESR) spin-trapping technique using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as the spin-trap reagent has been applied to detect free radical intermediates generated from FST. ESR results showed the concentration of the active species (OH) on FST is higher than those on F-doping TiO(2) (FT), Si-modifying TiO(2) (ST) and P25 titania. The degradation of pentachlorophenol (PCP) in the microwave-assisted photocatalysis (MAPC) process was faster than other processes including microwave-assisted direct photolysis (MADP), microwave process alone (MP) and dark process (DP). The photocatalytic activity of FST is much higher than that of ST, FT and P25 titania. It may be attributed to its strong capacity of absorption to the UV-vis irradiation and more hydroxyl radical on surface of FST. In MPAC process, 40 mg L(-1) PCP was completely degraded in 20 min and its corresponding mineralization efficiency was 71%, the pH of solutions decreased from 10.3 to 6.47 and the dechlorination was completed in 12 min. The intermediates products of PCP in MAPC process identified by GC/MS were trichlorophenols (TCP), tetrachlorophenols (TTCP) and tetrachlorocatechol (TTCC) and the possible mechanism of PCP degradation is proposed. PMID:18555596

  2. Cu2ZnSnS4 nanoflakes prepared by one step microwave irradiation technique: Effect of Cu concentration

    NASA Astrophysics Data System (ADS)

    Kandare, S. P.; Dhole, S. D.; Bhoraskar, V. N.; Dahiwale, S. S.

    2016-05-01

    Cu2ZnSnS4 (CZTS) nanoflakes were synthesized in one step by microwave irradiation method. Controlling the secondary phases in Copper Zinc Tin Sulfide (CZTS) material is critical, but it is necessary to control secondary phases in order to achieve the high efficiency solar cells made from CZTS. In the recent years, CZTS has shown its growing importance in thin film photovoltaic application because of its favorable optical and electrical properties. In this work, a systematic study has been carried out by properly controlling the copper concentration to get the pure phase of CZTS. X-ray diffraction shows the CZTS kesterite structure. Optical band gap estimated from UV-Visible spectroscopy was around 1.37eV. Systematic Raman study reveals the suppression of Cu2S peak with variation in copper concentration which otherwise was not clear from XRD and UV-visible data.

  3. On the acid-base properties of microwave irradiated hydrotalcite-like compounds containing Zn2+ and Mn2+.

    PubMed

    Sampieri, Alvaro; Lima, Enrique

    2009-04-01

    Microwave irradiated lamellar double hydroxides containing different divalent metals (Mn2+, Zn2+, or Mg2+) were prepared with Al3+ as the trivalent metal. Samples containing Mn2+ and Zn2+ were unstable at 400 degrees C, leading to formation of mixed oxides and spinel phases. Acid-base properties of the samples were characterized by nitromethane and CO2 adsorption followed by FTIR spectroscopy. Decomposition of adsorbed nitromethane leads to isocyanate species that acts as probe molecules of acid-base sites at the surface. These properties determine the ability of materials to retain CO2. Indeed, whereas Mn-O sites are able to interact directly with CO2 molecules, Mg-O and Zn-O are able to form carbonate species as a result of the CO2 sorption. PMID:19231817

  4. A Novel Method for Preparation of Gold NanoBipyramids Using Microwave Irradiation and Its Application in Immunosensors

    NASA Astrophysics Data System (ADS)

    Huynh, Trong Phat; Ngo, Vo Ke Thanh; Nguyen, Dang Giang; Nguyen, Hoang Phuong Uyen; Nghiem, Quoc Dat; Lam, Quang Vinh; Huynh, Thanh Dat

    2016-05-01

    Gold nanobipyramids (NBPs) have attracted attention for producing smart sensing devices as diagnostic tools in biotechnological and medical applications, because they show more advantageous plasmonic properties than comparable gold nanorods. Normally, NBPs were synthesized using seed-mediated growth process at room temperature. In this report, our group describes a method for synthesising of NBPs using microwave irradiation with ascorbic acid reduction and cetyltrimethylammonium bromide + silver nitrate (AgNO3) as capping agents. The advantages of this method are a highly effective approach to fast and uniform NBPs. The product was characterized by ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, and x-ray powder diffraction. As an application in quartz crystal microbalance immunosensors, NBPs is conjugated with the chloramphenicol antibodies for signal amplification to detect chloramphenicol residuals in the QCM system.

  5. Influence of the Polyvinyl Pyrrolidone Concentration on Particle Size and Dispersion of ZnS Nanoparticles Synthesized by Microwave Irradiation

    PubMed Central

    Soltani, Nayereh; Saion, Elias; Erfani, Maryam; Rezaee, Khadijeh; Bahmanrokh, Ghazaleh; Drummen, Gregor P. C.; Bahrami, Afarin; Hussein, Mohd Zobir

    2012-01-01

    Zinc sulfide semiconductor nanoparticles were synthesized in an aqueous solution of polyvinyl pyrrolidone via a simple microwave irradiation method. The effect of the polymer concentration and the type of sulfur source on the particle size and dispersion of the final ZnS nanoparticle product was carefully examined. Microwave heating generally occurs by two main mechanisms: dipolar polarization of water and ionic conduction of precursors. The introduction of the polymer affects the heating rate by restriction of the rotational motion of dipole molecules and immobilization of ions. Consequently, our results show that the presence of the polymer strongly affects the nucleation and growth rates of the ZnS nanoparticles and therefore determines the average particle size and the dispersion. Moreover, we found that PVP adsorbed on the surface of the ZnS nanoparticles by interaction of the C–N and C=O with the nanoparticle’s surface, thereby affording protection from agglomeration by steric hindrance. Generally, with increasing PVP concentration, mono-dispersed colloidal solutions were obtained and at the optimal PVP concentration (5%), sufficiently small size and narrow size distributions were obtained from both sodium sulfide and thioacetamide sulfur sources. Finally, the sulfur source directly influences the reaction mechanism and the final particle morphology, as well as the average size. PMID:23202906

  6. Improvement in gate bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors using microwave irradiation

    SciTech Connect

    Jo, Kwang-Won; Cho, Won-Ju

    2014-11-24

    In this study, we evaluated the effects of microwave irradiation (MWI) post-deposition-annealing (PDA) treatment on the gate bias stress instability of amorphous indium-gallium-zinc oxide thin-film transistors (a-IGZO TFTs) and compared the results with a conventional thermal annealing PDA treatment. The MWI-PDA-treated a-IGZO TFTs exhibited enhanced electrical performance as well as improved long-term stability with increasing microwave power. The positive turn-on voltage shift (ΔV{sub ON}) as a function of stress time with positive bias and varying temperature was precisely modeled on a stretched-exponential equation, suggesting that charge trapping is a dominant mechanism in the instability of MWI-PDA-treated a-IGZO TFTs. The characteristic trapping time and average effective barrier height for electron transport indicate that the MWI-PDA treatment effectively reduces the defects in a-IGZO TFTs, resulting in a superior resistance against gate bias stress.

  7. Highly efficient, quick and green synthesis of biarlys with chitosan supported catalyst using microwave irradiation in the absence of solvent.

    PubMed

    Baran, Talat; Açıksöz, Eda; Menteş, Ayfer

    2016-05-20

    The aim of this study was to develop a quick reaction that had high activity with a small amount of catalyst, which could be an eco-friendly alternative technique for the synthesis of biarlys in Suzuki coupling reactions. First, a novel chitosan Schiff base supported Pd(II) catalyst was synthesized, and its structure was illuminated with FTIR, (1)H NMR, (13)C NMR, TG/DTG, SEM/EDAX, XRD, ICP-OES, UV-vis, magnetic moment, and molar conductivity techniques. Subsequently, the catalytic activity of the catalyst was tested in Suzuki CC reactions under microwave irradiation using a solvent-free reaction condition. The catalytic tests showed an excellent activity with a small load of the catalyst (0.02mol%) in 4min. The catalyst showed seven runs without loss of activity, and high values of turnover numbers (TON) and turnover frequency (TOF) were obtained. The novel biopolymer supported Pd(II) catalyst provided much faster reaction times, higher yields, and reusability under microwave heating compared to classic heating methods. PMID:26917390

  8. Simultaneous retrievals of cloud optical depth and droplet concentration from solar irradiance and microwave liquid water path

    NASA Astrophysics Data System (ADS)

    Boers, Reinout

    1997-12-01

    A 20-month time series of continuous observations of microwave radiation and solar irradiance was used to estimate the cloud optical depth and droplet number concentration at the Cape Grim Baseline Air Pollution Station, Tasmania, (40°41'S, 144°41'E). The data were selected by wind directions. When the air was from "baseline" origin, i.e., it had travelled over long oceanic distances and was mostly devoid of anthropogenic influences, the retrieved droplet concentration and optical depth were lower than when the air was from "nonbaseline" i.e., continental origin. Therefore the observed variation in cloud microphysical properties reflects the difference between the natural background conditions over the Southern Ocean and continental conditions with elevated droplet counts. Under baseline conditions the retrieved cloud optical depth exhibits a weak but perceptible seasonal cycle that has been previously observed from satellite data with a minimum in the austral winter, and a maximum in the austral summer. The results demonstrate that routine retrievals of cloud microphysical properties are possible using only a pyranometer and a microwave liquid water radiometer.

  9. Preparation of starch-poly-glutamic acid graft copolymers by microwave irradiation and the characterization of their properties.

    PubMed

    Xu, Jingyuan; Krietemeyer, Elizabeth F; Finkenstadt, Victoria L; Solaiman, Daniel; Ashby, Richard D; Garcia, Rafael A

    2016-04-20

    Graft copolymers of waxy maize starch and poly-γ-glutamic acid (PGA) were produced in an aqueous solution using microwave irradiation. The microwave reaction conditions were optimized with regard to temperature and pH. The temperature of 180°C and pH7.0 were the best reaction conditions resulting in a PGA graft of 0.45% based on nitrogen analysis. The average graft content and graft efficiency for the starch-PGA graft copolymer prepared at 180°C and pH7.0 were 4.20% and 2.73%, respectively. The starch-PGA graft copolymer produced at 180°C and pH7.0 could absorb more than 20 times its own weight amount of water and form a gel. The preliminary rheology study revealed that the starch-PGA graft copolymer gel exhibited viscoelastic solid behavior while the control sample of waxy starch showed viscoelastic liquid behavior. PMID:26876849

  10. Effect of low-level laser irradiating point on immunity

    NASA Astrophysics Data System (ADS)

    Cai, ChangSong; Qi, Qiong-fang; Xin, Jiang

    1993-03-01

    This paper reports that cellular immune function was observed when He-Ne laser was used to irradiate `zusanli' point in rats using various power, time, and periods. The indicator was a lymphocyte transformation test (LTT) by MTT colorimetric analysis. The best irradiating condition was determined, the effect and both virtues and defects of the laser were compared with those of electropuncture. The results show (1) LTT was enhanced in the group of laser irradiating point, but LTT was not enhanced in non-point (t' test, P < 0.01). (2) Lower power -- 2 mW or 5 mW of irradiating for 15 - 20 min, was better; 10 mW or 20 mW of irradiating for 10 - 15 min was suitable. Prolonged irradiating time did not enhance the immune function of the rats. On the contrary, immune function was inhibited. (3) A 7-day period of irradiating was best (once a day, 10 mW for 10 min). Enhanced LTT was not seen when irradiation days were added (SNK, P > 0.05). (4) Laser irradiation point and electropuncture were compared with vehicle control, LTT in the former two groups was enhanced significantly (ANOVA, P < 0.01), and laser irradiating point and electropuncture had the same effect (SNK, P > 0.05). The data suggest that laser irradiating point was able to enhance cell immunity and the enhancement of LTT had a point specific characteristic. The best condition of laser irradiating point was 2 mW for 15 - 20 min, and 10 mW or 20 mW for 10 - 15 min. The best period was 7-day irradiation. The results show laser irradiating the point may activate the main and collateral channels system, then modify the immune function of the body. Our observations provide experimental evidence for proper clinical application of laser irradiating points. The paper theoretically discusses and analyzes the experiment results in detail.

  11. Phase Transformation of VO2 Nanoparticles Assisted by Microwave Heating

    PubMed Central

    Sikong, Lek.

    2014-01-01

    The microwave assisted synthesis nowadays attracts a great deal of attention. Monoclinic phase VO2 (M) was prepared from NH4VO3 and H2C2O4 · 2H2O by a rapid microwave assisted technique. The synthesis parameters, microwave irradiation time, microwave power, and calcinations temperature were systematically varied and their influences on the structure and morphology were evaluated. The microwave power level has been carried out in range 180–600 W. TEM analysis demonstrated nanosized samples. The structural and morphological properties were measured using XRD, TEM, and thermal analyses. The variations of vanadium phase led to thermochromic properties. PMID:24688438

  12. Desilication of ZSM-5 zeolites for mesoporosity development using microwave irradiation

    SciTech Connect

    Hasan, Zubair; Jun, Jong Won; Kim, Chul-Ung; Jeong, Kwang-Eun; Jeong, Soon-Yong; Jhung, Sung Hwa

    2015-01-15

    Highlights: • Microwaves have beneficial effects on desilication of zeolites. • Produced mesopores with microwaves have narrow pore-size distribution. • Advantages and disadvantages of various desilicating agents were also reported. - Abstract: Mesoporous ZSM-5 zeolite was obtained by desilication in alkaline solutions with microwave (MW) and conventional electric (CE) heating under hydrothermal conditions. Both methods were effective in the production of mesoporous zeolites; however, MW was more efficient than CE as it led to well-defined mesopores with relatively small sizes and a narrow size distribution within a short treatment time. Moreover, the mesoporous ZSM-5 obtained through this method was effective in producing less bulky products from an acid-catalyzed reaction, specifically the butylation of phenol. Finally, various bases were found to have advantages and disadvantages in desilication. NaOH was the most reactive; however, macroporosity could develop easily under a severe condition. Ammonia water was weakly reactive; however, it could be used to precisely control the pore architecture, and no ion exchange is needed for acid catalysis. Organic amines such as ethylenediamine can also be used in desilication.

  13. [Spectroscopic study on CdS nanoparticles prepared by microwave irradiation].

    PubMed

    Cheng, Wei-qing; Liu, Di; Yan, Zheng-yu

    2008-06-01

    CdS nanoparticles capped by mercaptoacetic acid have been successfully synthesized by microwave method employing thioacetamide as sulfur source, which was proved to be a simple, rapid and specific mothod compared with traditional synthetical methods, such as precipitation, sol-gel, solvo-thermal method and so on. The concrete procedure synthesizing CdS nanoparticles was as follows: Cd(NO3)2 (40 mL, 5 mmol c L(-1)) was titrated with mercaptoacetic acid to pH 2.0, resulting in a turbid blue solution. NaOH (0.1 mol x L(-1)) was then added dropwise until the pH was 7 and the solution was again colorless. While quickly stirring the solution, 40 mL of 5 mmol x L(-1) CH3CSNH2 was added. Subsequently, the solution was adjusted to pH 9.0 and placed in a microwave oven for 25 min with power 30% (it means that if microwave works in a 30 s regime, it works 6 s, and does not work 24 s. This is some kind of pulse regime, but the totalpower is still 100%). This kind of nanoparticles were water-soluble and symmetrical. The diameter of CdS nanoparticles which have a spherical morphology was determined to be 12 nm by transmission electron microscopy(TEM), which posess perfect uniforminty. According to literatures report, there are two kinds of emission peak: one is edge-emission peak, and the other is surface blemish emission. In contrast to edge-emission peak, the surface blemish emission shows red shift on fluorescence spectra. In the present paper, the prominent peak of CdS QDs fluorescence spectrum was located at 490 nm, the humpbacked peak caused by surface blemish of CdS nanoparticles was located at 565 nm. However, the surface blemish emission was unconspicuous, thus we can conclude that the synthetical CdS QDs possesses excellent luminescence capability and favorable structure. The size and absorption and fluorescence spectra of CdS nanoparticles at different microwave power, pH value, reaction time and different sulfur source were investigated. The result showed that the

  14. Restraint chair with rowing-like movement for exposing exercising nonhuman primates to microwave irradiation

    SciTech Connect

    Knepton, J.; Ezell, C.; de Lorge, J.

    1983-04-20

    Design and construction of a Styrofoam exercise restraint chair is described for use with rhesus monkeys exposed to microwaves. Monkeys usually learn the rowing-like motion of the device within five 1-hour conditioning sessions. Radiation intensity measure of the chair and an example animal experiment demonstrated the chair's suitability for bioelectromagnetic studies. Results of a series of base-line behavioral sessions demonstrated concomitant exercise work load effects on colonic temperature, heart rate, correct response rate, and post-reinforcement pause time. With additional instrumentation, detection of minute disturbances of integrated psychological and physiological mechanisms by unusual environmental factors may be possible.

  15. Study of deep level characteristics in the neutrons irradiated Si structures by combining pulsed and steady-state spectroscopy techniques

    NASA Astrophysics Data System (ADS)

    Gaubas, E.; Kalendra, V.; Ceponis, T.; Uleckas, A.; Tekorius, A.; Vaitkus, J.; Velicka, A.

    2012-11-01

    The standard methods, such as capacitance deep level transient spectroscopy (C-DLTS) and thermally stimulated current (TSC) techniques are unsuitable for the analysis of heavily irradiated devices. In this work, therefore, several steady-state and pulsed techniques have been combined to comprehensively evaluate parameters of radiation defects and functional characteristics of the irradiated Si pin detectors. In order to understand defects created by radiation and evaluate their evolution with fluence, C-DLTS and TSC techniques have been employed to make a baseline identification of the radiation induced traps after irradiation with a rather small neutron fluence of 1012 cm-2. The steady-state photo-ionization spectroscopy (PIS) technique has been involved to correlate thermal- and photo- activation energies for definite radiation defects. A contactless technique for simultaneous measurements of the carrier lifetime and the parameters of deep levels based on microwave probed pulsed photo-conductivity (MW-PC) spectroscopy has been applied to correlate carrier capture cross-sections and densities of the identified different radiation defects. A technique for spectroscopy of deep levels in junction structures (BELIV) based on measurements of barrier capacitance charging current transient changes due to additional spectrally resolved pulsed illumination has been applied to evaluate the functional characteristics of the irradiated diodes. Pulsed spectroscopic measurements were implemented by combining the analysis of generation current and of barrier capacitance charging transients modified by a single fs pulse of illumination generated by an optical parametric oscillator of varied wavelength in the range from 0.5 to 10 μm. Several deep levels with activation energy in the range of 0.18-0.8 eV have been resolved from spectral analysis in the samples of Si grown by magnetic field applied Czochralski (MCz) technology.

  16. The effect of non-contact heating (microwave irradiation) and contact heating (annealing process) on properties and performance of polyethersulfone nanofiltration membranes

    NASA Astrophysics Data System (ADS)

    Mansourpanah, Y.; Madaeni, S. S.; Rahimpour, A.; Farhadian, A.

    2009-07-01

    In this work the effect of microwave irradiation on morphology and performance of polyethersulfone (PES) membranes was investigated. The membranes were prepared with 20 wt.% of PES by phase inversion method. N, N-dimethylformamide (DMF) and mixture of water and ethyl alcohol (90/10 vol.%) were employed as solvent and coagulant respectively. Polyvinylpirrolidone (PVP) with the concentration of 2 wt.% was selected as pore former. The effects of irradiation time (10, 30, 60, 90, 120 s) and microwave power (180, 360, 720 and 900 W) on structure and performance of membranes were studied. Increasing the irradiation time and power caused variation in permeate flux and ion rejection. Moreover, the effects of annealing processes (60, 70, 80 °C) were studied. Transmembrane pressure was selected around 1.5 MPa for all experiments. Scanning electron microscope (SEM) and atomic force microscope (AFM) were employed to describe the surface morphology of the prepared membranes. The effect of microwave irradiation time in different power revealed alterations in membrane surface morphology and AFM images represented that surface parameters (such as surface roughness) have been changed. The membrane exhibited moderate rejection (47%) and low permeate flux (4.5 kg/m 2 h) at 80 °C for NaCl solution. The SEM images indicate that the dense skin layer is formed at 80 °C annealing.

  17. GROWTH AND DEVELOPMENT OF MICE OFFSPRING AFTER IRRADIATION IN UTERO WITH 2,450-MHZ MICROWAVES

    EPA Science Inventory

    Mice offspring irradiated in utero with 2,450-MHz radio-frequency (RF) radiation at 0 or 28 mW/cm. sq. (whole-body averaged specific absorption rate = 0 or 16.5 W/kg) for 100 minutes daily on days 6 through 17 of gestation were evaluated for maturation and development on days 1, ...

  18. Hydrophilic and blue fluorescent N-doped carbon dots from tartaric acid and various alkylol amines under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Xu, Minghan; Xu, Shusheng; Yang, Zhi; Shu, Mengjun; He, Guili; Huang, Da; Zhang, Liling; Li, Li; Cui, Daxiang; Zhang, Yafei

    2015-09-01

    The desired control of particle size, doping element composition, and surface structure of carbon dots (CDs) are vital for understanding the fluorescence mechanism and exploring their potential applications. Herein, nitrogen-doped CDs (N-doped CDs) have been synthesized with tartaric acid and various alkylol amines (monoethanolamine, biethanolamine and triethanolamine) under microwave irradiation. A systematic investigation was performed to characterize the N-doped CDs. It is found that with increasing nitrogen proportion, the fluorescent quantum yield and lifetime of N-doped CDs increases, whereas cell toxicity decreases. In other words, N-doped CDs synthesized by tartaric acid and monoethanolamine have the highest nitrogen content, the highest fluorescent quantum yield, the longest lifetime and the lowest cell toxicity. A corresponding mechanism has been proposed. Moreover, as-synthesized N-doped CDs have been applied for selectively detecting the Fe3+ ion and writing letters as a fluorescent ink.The desired control of particle size, doping element composition, and surface structure of carbon dots (CDs) are vital for understanding the fluorescence mechanism and exploring their potential applications. Herein, nitrogen-doped CDs (N-doped CDs) have been synthesized with tartaric acid and various alkylol amines (monoethanolamine, biethanolamine and triethanolamine) under microwave irradiation. A systematic investigation was performed to characterize the N-doped CDs. It is found that with increasing nitrogen proportion, the fluorescent quantum yield and lifetime of N-doped CDs increases, whereas cell toxicity decreases. In other words, N-doped CDs synthesized by tartaric acid and monoethanolamine have the highest nitrogen content, the highest fluorescent quantum yield, the longest lifetime and the lowest cell toxicity. A corresponding mechanism has been proposed. Moreover, as-synthesized N-doped CDs have been applied for selectively detecting the Fe3+ ion and writing

  19. Pyrolysis of oil palm empty fruit bunch biomass pellets using multimode microwave irradiation.

    PubMed

    Salema, Arshad Adam; Ani, Farid Nasir

    2012-12-01

    Oil palm empty fruit bunch pellets were subjected to pyrolysis in a multimode microwave (MW) system (1 kW and 2.45 GHz frequency) with and without the MW absorber, activated carbon. The ratio of biomass to MW absorber not only affected the temperature profiles of the EFB but also pyrolysis products such as bio-oil, char, and gas. The highest bio-oil yield of about 21 wt.% was obtained with 25% MW absorber. The bio-oil consisted of phenolic compounds of about 60-70 area% as detected by GC-MS and confirmed by FT-IR analysis. Ball lightning (plasma arc) occurred due to residual palm oil in the EFB biomass without using an MW absorber. The bio-char can be utilized as potential alternative fuel because of its heating value (25 MJ/kg). PMID:23026320

  20. SOLVENT-FREE CHEMICAL TRANSFORMATIONS USING MICROWAVE IRRADIATION. 32ND ACS CENTRAL REGIONAL MEETING, MAY 16-19, 2000, ABSTRACTS & PROGRAM, NORTHERN KENTUCKY CONVENTION CENTER, COVINGTON, KY. AMERICAN CHEMICAL SOCIETY, 1999, P. 121.

    EPA Science Inventory

    Microwave-expedited solvent-free synthetic processes will be described that involve the exposure of neat reactants to microwave (MW) irradiation in the presence of supported reagents or catalysts on minineral oxides. Recent developments will be presented on the synthetic utility...

  1. Fast transmethylation of total lipids in dried blood by microwave irradiation and its application to a population study.

    PubMed

    Lin, Yu Hong; Hanson, Jennifer A; Strandjord, Sarah E; Salem, Nicholas M; Dretsch, Michael N; Haub, Mark D; Hibbeln, Joseph R

    2014-08-01

    A methodology combining finger-pricked blood sampling, microwave accelerated fatty acid assay, fast gas chromatography data acquisition, and automated data processing was developed, evaluated and applied to a population study. Finger-pricked blood was collected on filter paper previously impregnated with 0.05 mg of the antioxidant butylated hydroxytoluene and air-dried at room temperature. Transmethylation was accelerated by microwave irradiation in an explosion-proof multimode microwave reaction system. The chemical procedure was based on a one-step direct transmethylation procedure catalyzed by acetyl chloride. The short-term stability of PUFA in blood dried on filter paper and storage at room temperature was examined using venous blood. The recoveries ranged from 97 to 101 % for the categorized fatty acids as well as the ratios of n-6 to n-3 PUFA and the n-3 % highly unsaturated fatty acid. Specifically, recoveries were 99, 98, 97, and 97 % for linoleic acid (18:2n-6), arachidonic acid (ARA), α-linolenic acid (ALA), and docosahexaenoic acid (DHA), respectively. The mol% (mean ± SD, 95 % confidence interval) of fatty acid composition in subjects from the population study was determined as 36.2 ± 3.8 (35.8, 36.7), 23.2 ± 3.0 (22.8, 23.5), 36.8 ± 3.5 (36.4, 37.2) and 3.79 ± 1.0 (3.68, 3.91) for the saturated, monounsaturated, n-6 and n-3 PUFA, respectively. Individually, the mean mol% (95 % CI) was 22.6 (22.3, 22.9) for 18:2n-6, 9.5 (9.3, 9.7) for ARA, 0.51 (0.49, 0.53) for ALA, 0.42 (0.38, 0.47) for eicosapentaenoic acid (EPA), and 1.67 (1.61, 1.73) for DHA. This methodology provides an accelerated yet high-efficiency, chemically safe, and temperature-controlled transmethylation, with diverse laboratory applications including population studies. PMID:24986160

  2. Fast Transmethylation of Total Lipids in Dried Blood by Microwave Irradiation and its Application to a Population Study

    PubMed Central

    Lin, Yu Hong; Hanson, Jennifer A.; Strandjord, Sarah E.; Salem, Nicholas M.; Dretsch, Michael N.; Haub, Mark D.; Hibbeln, Joseph R.

    2014-01-01

    A methodology combining finger-pricked blood sampling, microwave accelerated fatty acid assay, fast gas chromatography data acquisition, and automated data processing was developed, evaluated and applied to a population study. Finger-pricked blood was collected on filter paper previously impregnated with 0.05 mg of the antioxidant butylated hydroxytoluene and air-dried at room temperature. Transmethylation was accelerated by microwave irradiation in an explosion-proof multimode microwave reaction system. The chemical procedure was based on a one-step direct transmethylation procedure catalyzed by acetyl chloride. The short-term stability of PUFA in blood dried on filter paper and stored overnight at room temperature was examined using venous blood. The recoveries ranged from 97–101 % for the categorized fatty acids as well as the ratios of n-6 to n-3 PUFA and the n-3% highly unsaturated fatty acid. Specifically, recoveries were 99, 98, 97, and 97 % for linoleic acid (18:2n-6), arachidonic acid (ARA), α-linolenic acid (ALA), and docosahexaenoic acid (DHA), respectively. The mol% (mean ± SD, 95% confidence interval) of fatty acid composition in subjects from the population study was determined as 36.2±3.8 (35.8, 36.7), 23.2±3.0 (22.8, 23.5), 36.8±3.5 (36.4, 37.2) and 3.79±1.0 (3.68, 3.91) for the saturated, monounsaturated, n-6 and n-3 PUFA, respectively. Individually, the mean mol% (95% CI) was 22.6 (22.3, 22.9) for 18:2n-6, 9.5 (9.3, 9.7) for ARA, 0.51 (0.49, 0.53) for ALA, 0.42 (0.38, 0.47) for eicosapentaenoic acid (EPA), and 1.67 (1.61, 1.73) for DHA. This methodology provides an accelerated yet high-efficiency, chemically safe, and temperature-controlled transmethylation, with diverse laboratory applications including population studies. PMID:24986160

  3. Preparation of Pd supported on La(Sr)-Mn-O Perovskite by microwave Irradiation Method and Its Catalytic Performances for the Methane Combustion

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Yuan, Fulong; Niu, Xiaoyu; Zhu, Yujun

    2016-01-01

    In this work, a series of palladium supported on the La0.8Sr0.2MnO3.15 perovskite catalysts (Pd/LSM-x) with different Pd loading were prepared by microwave irradiation processing plus incipient wetness impregnation method and characterized by XRD, TEM, H2-TPR and XPS. These catalysts were evaluated on the lean CH4 combustion. The results show that the Pd/LSM-x samples prepared by microwave irradiation processing possess relative higher surface areas than LSM catalyst. The addition of Pd to the LSM leads to the increase in the oxygen vacancy content and the enhancement in the mobility of lattice oxygen which play an important role on the methane combustion. The Pd/LSM-3 catalysts with 4.2wt% Pd loading exhibited the best performance for CH4 combustion that temperature for 10% and 90% of CH4 conversion is 315 and 520 °C.

  4. Preparation of Pd supported on La(Sr)-Mn-O Perovskite by microwave Irradiation Method and Its Catalytic Performances for the Methane Combustion.

    PubMed

    Wang, Wei; Yuan, Fulong; Niu, Xiaoyu; Zhu, Yujun

    2016-01-01

    In this work, a series of palladium supported on the La0.8Sr0.2MnO3.15 perovskite catalysts (Pd/LSM-x) with different Pd loading were prepared by microwave irradiation processing plus incipient wetness impregnation method and characterized by XRD, TEM, H2-TPR and XPS. These catalysts were evaluated on the lean CH4 combustion. The results show that the Pd/LSM-x samples prepared by microwave irradiation processing possess relative higher surface areas than LSM catalyst. The addition of Pd to the LSM leads to the increase in the oxygen vacancy content and the enhancement in the mobility of lattice oxygen which play an important role on the methane combustion. The Pd/LSM-3 catalysts with 4.2wt% Pd loading exhibited the best performance for CH4 combustion that temperature for 10% and 90% of CH4 conversion is 315 and 520 °C. PMID:26781628

  5. Preparation of Pd supported on La(Sr)-Mn-O Perovskite by microwave Irradiation Method and Its Catalytic Performances for the Methane Combustion

    PubMed Central

    Wang, Wei; Yuan, Fulong; Niu, Xiaoyu; Zhu, Yujun

    2016-01-01

    In this work, a series of palladium supported on the La0.8Sr0.2MnO3.15 perovskite catalysts (Pd/LSM-x) with different Pd loading were prepared by microwave irradiation processing plus incipient wetness impregnation method and characterized by XRD, TEM, H2-TPR and XPS. These catalysts were evaluated on the lean CH4 combustion. The results show that the Pd/LSM-x samples prepared by microwave irradiation processing possess relative higher surface areas than LSM catalyst. The addition of Pd to the LSM leads to the increase in the oxygen vacancy content and the enhancement in the mobility of lattice oxygen which play an important role on the methane combustion. The Pd/LSM-3 catalysts with 4.2wt% Pd loading exhibited the best performance for CH4 combustion that temperature for 10% and 90% of CH4 conversion is 315 and 520 °C. PMID:26781628

  6. Coherent interaction with two-level fluctuators using near field scanning microwave microscopy

    PubMed Central

    de Graaf, S. E.; Danilov, A. V.; Kubatkin, S. E.

    2015-01-01

    Near field Scanning Microwave Microscopy (NSMM) is a scanning probe technique that non-invasively can obtain material properties on the nano-scale at microwave frequencies. While focus has been on developing room-temperature systems it was recently shown that this technique can potentially reach the quantum regime, opening up for applications in materials science and device characterization in solid state quantum information processing. In this paper we theoretically investigate this new regime of NSMM. Specifically we show that interaction between a resonant NSMM probe and certain types of two-level systems become possible when the NSMM probe operates in the (sub-) single photon regime, and we expect a high signal-to-noise ratio if operated under the right conditions. This would allow to detect single atomic material defects with energy splittings in the GHz range with nano-scale resolution, provided that individual defects in the material under study are well enough separated. We estimate that this condition is fulfilled for materials with loss tangents below tan δ ∼ 10−3 which holds for materials used in today’s quantum circuits and devices where typically tan δ < 10−5. We also propose several extensions to a resonant NSMM that could improve sensitivity and functionality also for microscopes operating in a high power regime. PMID:26597218

  7. Coherent interaction with two-level fluctuators using near field scanning microwave microscopy

    NASA Astrophysics Data System (ADS)

    de Graaf, S. E.; Danilov, A. V.; Kubatkin, S. E.

    2015-11-01

    Near field Scanning Microwave Microscopy (NSMM) is a scanning probe technique that non-invasively can obtain material properties on the nano-scale at microwave frequencies. While focus has been on developing room-temperature systems it was recently shown that this technique can potentially reach the quantum regime, opening up for applications in materials science and device characterization in solid state quantum information processing. In this paper we theoretically investigate this new regime of NSMM. Specifically we show that interaction between a resonant NSMM probe and certain types of two-level systems become possible when the NSMM probe operates in the (sub-) single photon regime, and we expect a high signal-to-noise ratio if operated under the right conditions. This would allow to detect single atomic material defects with energy splittings in the GHz range with nano-scale resolution, provided that individual defects in the material under study are well enough separated. We estimate that this condition is fulfilled for materials with loss tangents below tan δ ˜ 10-3 which holds for materials used in today’s quantum circuits and devices where typically tan δ < 10-5. We also propose several extensions to a resonant NSMM that could improve sensitivity and functionality also for microscopes operating in a high power regime.

  8. Coherent interaction with two-level fluctuators using near field scanning microwave microscopy.

    PubMed

    de Graaf, S E; Danilov, A V; Kubatkin, S E

    2015-01-01

    Near field Scanning Microwave Microscopy (NSMM) is a scanning probe technique that non-invasively can obtain material properties on the nano-scale at microwave frequencies. While focus has been on developing room-temperature systems it was recently shown that this technique can potentially reach the quantum regime, opening up for applications in materials science and device characterization in solid state quantum information processing. In this paper we theoretically investigate this new regime of NSMM. Specifically we show that interaction between a resonant NSMM probe and certain types of two-level systems become possible when the NSMM probe operates in the (sub-) single photon regime, and we expect a high signal-to-noise ratio if operated under the right conditions. This would allow to detect single atomic material defects with energy splittings in the GHz range with nano-scale resolution, provided that individual defects in the material under study are well enough separated. We estimate that this condition is fulfilled for materials with loss tangents below tan δ ∼ 10(-3) which holds for materials used in today's quantum circuits and devices where typically tan δ < 10(-5). We also propose several extensions to a resonant NSMM that could improve sensitivity and functionality also for microscopes operating in a high power regime. PMID:26597218

  9. Synthesis of Ketones through Microwave Irradiation Promoted Metal-Free Alkylation of Aldehydes by Activation of C(sp(3))-H Bond.

    PubMed

    Zhang, Xinying; Wang, Zhangxin; Fan, Xuesen; Wang, Jianji

    2015-11-01

    In this paper, a novel methodology for the synthesis of ketones via microwave irradiation promoted direct alkylation of aldehydes by activation of the inert C(sp(3))-H bond has been developed. Notably, the reactions were accomplished under metal-free conditions and used commercially available aldehydes and cycloalkanes as substrates without prefunctionalization. By using this novel method, an alternative synthetic approach toward the key intermediates for the preparation of the pharmaceutically valuable oxaspiroketone derivatives was successfully established. PMID:26457376

  10. Irradiation creep in austenitic and ferritic steels irradiated in a tailored neutron spectrum to induce fusion reactor levels of helium

    SciTech Connect

    Grossbeck, M.L.; Gibson, L.T.; Jitsukawa, S.

    1996-04-01

    Six austenitic stainless steels and two ferritic alloys were irradiated sequentially in two research reactors where the neutron spectrum was tailored to produce a He production rate typical of a fusion device. Irradiation began in the Oak Ridge Research Reactor where an atomic displacement level of 7.4 dpa was achieved and was then transferred to the High Flux Isotope Reactor for the remainder of the irradiation to a total displacement level of 19 dpa. Temperatures of 60 and 330{degree}C are reported on. At 330{degree}C irradiation creep was found to be linear in stress and fluence with rates in the range of 1.7 - 5.5 x 10{sup -4}% MPa{sup -1} dpa{sup -1}. Annealed and cold-worked materials exhibited similar creep rates. There is some indication that austenitic alloys with TiC or TiO precipitates had a slightly higher irradiation creep rate than those without. The ferritic alloys HT-9 and Fe-16Cr had irradiatoin creep rates about 0.5 x 10{sup -4}% MPa{sup -1} dpa{sup -1}. No meaningful data could be obtained from the tubes irradiated at 60{degree}C because of damage to the tubes.

  11. Synthesis of Visible-Light-Responsive Cu and N-Codoped AC/TiO2 Photocatalyst Through Microwave Irradiation.

    PubMed

    Tian, Fei; Wu, Zhansheng; Yan, Yujun; Ye, Bang-Ce; Liu, Dandan

    2016-12-01

    N-Cu-activated carbon (AC)/TiO2 nanoparticles were prepared by the sol-gel technique through microwave irradiation to modify the visible-light response of TiO2. Their structure, surface chemical composition, and optical absorption properties were characterized. The results showed that the codoped particles had a higher surface area and smaller particle size than pure AC/TiO2 and monodoped AC/TiO2. X-ray photoelectron spectroscopy of N-Cu-AC/TiO2 showed that Cu atoms replaced Ti atom sites, whereas N atoms occupied the O atom sites and interstitial sites in the TiO2 lattice, which changed the electric and band-gap structures of the photocatalyst. N or Cu monodoping of AC/TiO2 reduced the energy band gap of TiO2 from 2.86 eV to 2.81 or 2.61 eV, respectively. In (N, Cu)-codoped AC/TiO2, N and Cu were incorporated into the TiO2 framework and narrowed the band gap of TiO2 to 2.47 eV, causing a large red shift and enhancing visible-light utilization efficiency. Photocatalytic activities were further examined by formaldehyde degradation under visible-light irradiation. N-Cu-AC/TiO2 was found to have the highest activity (ca. 94.4 % formaldehyde degradation efficiency) and to be easily recyclable. These results show an important and innovative method of improving AC/TiO2 activity by modifying the nonmetallic and metallic species. PMID:27295260

  12. Synthesis of Visible-Light-Responsive Cu and N-Codoped AC/TiO2 Photocatalyst Through Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Tian, Fei; Wu, Zhansheng; Yan, Yujun; Ye, Bang-Ce; Liu, Dandan

    2016-06-01

    N-Cu-activated carbon (AC)/TiO2 nanoparticles were prepared by the sol-gel technique through microwave irradiation to modify the visible-light response of TiO2. Their structure, surface chemical composition, and optical absorption properties were characterized. The results showed that the codoped particles had a higher surface area and smaller particle size than pure AC/TiO2 and monodoped AC/TiO2. X-ray photoelectron spectroscopy of N-Cu-AC/TiO2 showed that Cu atoms replaced Ti atom sites, whereas N atoms occupied the O atom sites and interstitial sites in the TiO2 lattice, which changed the electric and band-gap structures of the photocatalyst. N or Cu monodoping of AC/TiO2 reduced the energy band gap of TiO2 from 2.86 eV to 2.81 or 2.61 eV, respectively. In (N, Cu)-codoped AC/TiO2, N and Cu were incorporated into the TiO2 framework and narrowed the band gap of TiO2 to 2.47 eV, causing a large red shift and enhancing visible-light utilization efficiency. Photocatalytic activities were further examined by formaldehyde degradation under visible-light irradiation. N-Cu-AC/TiO2 was found to have the highest activity (ca. 94.4 % formaldehyde degradation efficiency) and to be easily recyclable. These results show an important and innovative method of improving AC/TiO2 activity by modifying the nonmetallic and metallic species.

  13. A critical assessment of the specific role of microwave irradiation in the synthesis of ZnO micro- and nanostructured materials.

    PubMed

    Baghbanzadeh, Mostafa; Skapin, Srečo D; Orel, Zorica Crnjak; Kappe, C Oliver

    2012-04-27

    A rapid, microwave-assisted hydrothermal method has been developed to access ultrafine ZnO hexagonal microrods of about 3-4 μm in length and 200-300 nm in width by using a 1:5 zinc nitrate/urea precursor system. The size and morphology of these ZnO materials can be influenced by subtle changes in precursor concentration, solvent system, and reaction temperature. Optimized conditions involve the use of a 1:3 water/ethylene glycol solvent system and 10 min microwave heating at 150 °C in a dedicated single-mode microwave reactor with internal temperature control. Carefully executed control experiments ensuring identical heating and cooling profiles, stirring rates, and reactor geometries have demonstrated that for these preparations of ZnO microrods no differences between conventional and microwave dielectric heating are observed. The resulting ZnO microrods exhibited the same crystal phase, primary crystallite size, shape, and size distribution regardless of the heating mode. Similar results were obtained for the ultrafast preparation of ZnO nanoparticles with diameters of approximately 20 nm, synthesized by means of a nonaqueous sol-gel process at 200 °C from a Zn(acac)(2) (acac=acetylacetonate) precursor in benzyl alcohol. The specific role of microwave irradiation in enhancing these nanomaterial syntheses can thus be attributed to a purely thermal effect as a result of higher reaction temperatures, more rapid heating, and a better control of process parameters. PMID:22454084

  14. Cranial irradiation regulates CREB-BDNF signaling and variant BDNF transcript levels in the mouse hippocampus.

    PubMed

    Son, Yeonghoon; Yang, Miyoung; Kang, Sohi; Lee, Sueun; Kim, Jinwook; Kim, Juhwan; Park, Seri; Kim, Joong-Sun; Jo, Sung-Kee; Jung, Uhee; Shin, Taekyun; Kim, Sung-Ho; Wang, Hongbing; Moon, Changjong

    2015-05-01

    The brain can be exposed to ionizing radiation in various ways, and such irradiation can trigger adverse effects, particularly on learning and memory. However, the precise mechanisms of cognitive impairments induced by cranial irradiation remain unknown. In the hippocampus, brain-derived neurotrophic factor (BDNF) plays roles in neurogenesis, neuronal survival, neuronal differentiation, and synaptic plasticity. The significance of BDNF transcript variants in these contexts is becoming clearer. In the present study, both object recognition memory and contextual fear conditioning task performance in adult C57BL/6 mice were assessed 1 month after a single exposure to cranial irradiation (10 Gy) to evaluate hippocampus-related behavioral dysfunction following such irradiation. Furthermore, changes in the levels of BDNF, the cAMP-response element binding protein (CREB) phosphorylation, and BDNF transcript variants were measured in the hippocampus 1 month after cranial irradiation. On object recognition memory and contextual fear conditioning tasks, mice evaluated 1 month after irradiation exhibited significant memory deficits compared to sham-irradiated controls, but no apparent change was evident in locomotor activity. Both phosphorylated CREB and BDNF protein levels were significantly downregulated after irradiation of the hippocampus. Moreover, the levels of mRNAs encoding common BDNF transcripts, and exons IIC, III, IV, VII, VIII, and IXA, were significantly downregulated after irradiation. The reductions in CREB phosphorylation and BDNF expression induced by differential regulation of BDNF hippocampal exon transcripts may be associated with the memory deficits evident in mice after cranial irradiation. PMID:25792232

  15. Novel synthesis of holey reduced graphene oxide (HRGO) by microwave irradiation method for anode in lithium-ion batteries.

    PubMed

    Alsharaeh, Edreese; Ahmed, Faheem; Aldawsari, Yazeed; Khasawneh, Majdi; Abuhimd, Hatem; Alshahrani, Mohammad

    2016-01-01

    In this work, holey reduced graphene oxide (HRGO) was synthesized by the deposition of silver (Ag) nanoparticles onto the reduced graphene oxide (RGO) sheets followed by nitric acid treatment to remove Ag nanoparticles by microwave irradiation to form a porous structure. The HRGO were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), and Raman spectroscopy. These novel HRGO exhibited high rate capability with excellent cycling stability as an anode material for lithium-ion batteries. The results have shown an excellent electrochemical response in terms of charge/discharge capacity (423 mAh/g at 100 mA/g). The cyclic performance was also exceptional as a high reversible capacity (400 mAh/g at 100 mA/g) was retained for 100 charge/discharge cycles. This fascinating electrochemical performance can be ascribed to their specific porous structure (2-5 nm pores) and high surface area (457 m(2)/g), providing numerous active sites for Li(+) insertion, high electrical conductivity, low charge-transfer resistance across the electrolyte-electrode interface, and improved structural stability against the local volume change during Li(+) insertion-extraction. Such electrodes are envisioned to be mass scalable with relatively simple and low-cost fabrication procedures, thereby providing a clear pathway toward commercialization. PMID:27457356

  16. Performance improvement of the resistive memory properties of InGaZnO thin films by using microwave irradiation

    NASA Astrophysics Data System (ADS)

    Hwang, Yeong-Hyeon; An, Ho-Myoung; Cho, Won-Ju

    2014-01-01

    Microwave irradiation (MWI) at low temperature was employed in resistive random access memory (ReRAM) fabrication with InGaZnO (IGZO) thin-films as a switching medium, and the resistive switching behaviors were compared with conventional thermal annealing (CTA) process. A surface roughness of the MWI-treated IGZO layer is smoother than that of the CTA-treated layer. An electrical conduction mechanism of the MWI-treated device is similar to that of the pristine device, whereas the CTA device exhibits a different mechanism. After MWI treatment, the current ON/OFF ratio of IGZO ReRAMs significantly increased from 0.49 × 101 to 1.16 × 102, which was ascribed to the reduction in the OFF current. Further, the enlarged ON/OFF resistance window allowed sufficient data retention of >10 years at 85 °C. Owing to its smoother surface for stable resistive switching, low thermal budget, and process simplicity, MWI has great potential for metal-oxide ReRAMs in transparent and flexible system-on-panel applications.

  17. One pot synthesis, structural and spectral analysis of some symmetrical curcumin analogues catalyzed by calcium oxide under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Elavarasan, S.; Bhakiaraj, D.; Chellakili, B.; Elavarasan, T.; Gopalakrishnan, M.

    2012-11-01

    A series of sixteen number of curcumin analogues have been synthesized under microwave irradiation using calcium oxide as a catalyst. The synthesized compounds have been characterized using FT-IR, MS, elemental analysis, 1H and 13C NMR spectroscopic techniques. The UV-Vis absorption studies for these compounds have been studied in order to provide the electronic transitions taking place in the molecule. When compared to the curcumin ((1E,4Z,6E)-5-hydroxy-1,7-bis(4-hydroxy-3-methoxyphenyl)hepta-1,4,6-trien-3-one), the absorption maxima, λmax for all the synthesized curcumin analogues with a variety of substituents gets blue shifted i.e., hypsochromic shift was observed. This shift may be assigned to the change of dipole moment within the solvated molecule. Theoretical calculations regarding the optimization of the synthesized molecules, electronic properties like highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) and mapped electron density surface diagrams were done. The geometrical energy, dipole moments and heat of formation values have also been calculated using the ArgusLab package by AM1 semi-empirical method.

  18. Microwave irradiated Ni-MnOx/C as an electrocatalyst for methanol oxidation in KOH solution for fuel cell application

    NASA Astrophysics Data System (ADS)

    Hameed, R. M. Abdel

    2015-12-01

    Ni-MnOx/C electrocatalyst was synthesized by the reduction of nickel precursor salt on MnOx/C powder using NaBH4 and the deposition process was motivated with the aid of microwave irradiation. Finer nickel nanoparticles were detected in Ni-MnOx/C using transmission electron microscopy with a lower particle size of 4.5 nm compared to 6 nm in Ni/C. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy (EIS) were applied to study the electrocatalytic activity of Ni-MnOx/C for methanol oxidation in 0.5 M KOH solution. The presence of 7.5 wt.% MnOx in Ni-MnOx/C enhanced the oxidation current density by 1.43 times. The catalytic rate constant of methanol oxidation at Ni-MnOx/C was calculated as 3.26 × 103 cm3 mol-1 s-1. An appreciable shift in the maximum frequency at the transition from the resistive to capacitive regions to a higher value in Bode plots of Ni-MnOx/C was shown when compared to Ni/C. It was accompanied by lowered phase angle values. The lowered Warburg impedance value (W) of Ni-MnOx/C at 400 mV confirmed the faster methanol diffusion rate at its surface.

  19. Novel synthesis of holey reduced graphene oxide (HRGO) by microwave irradiation method for anode in lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Alsharaeh, Edreese; Ahmed, Faheem; Aldawsari, Yazeed; Khasawneh, Majdi; Abuhimd, Hatem; Alshahrani, Mohammad

    2016-07-01

    In this work, holey reduced graphene oxide (HRGO) was synthesized by the deposition of silver (Ag) nanoparticles onto the reduced graphene oxide (RGO) sheets followed by nitric acid treatment to remove Ag nanoparticles by microwave irradiation to form a porous structure. The HRGO were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), and Raman spectroscopy. These novel HRGO exhibited high rate capability with excellent cycling stability as an anode material for lithium-ion batteries. The results have shown an excellent electrochemical response in terms of charge/discharge capacity (423 mAh/g at 100 mA/g). The cyclic performance was also exceptional as a high reversible capacity (400 mAh/g at 100 mA/g) was retained for 100 charge/discharge cycles. This fascinating electrochemical performance can be ascribed to their specific porous structure (2–5 nm pores) and high surface area (457 m2/g), providing numerous active sites for Li+ insertion, high electrical conductivity, low charge-transfer resistance across the electrolyte–electrode interface, and improved structural stability against the local volume change during Li+ insertion–extraction. Such electrodes are envisioned to be mass scalable with relatively simple and low-cost fabrication procedures, thereby providing a clear pathway toward commercialization.

  20. A novel combined pretreatment of ball milling and microwave irradiation for enhancing enzymatic hydrolysis of microcrystalline cellulose.

    PubMed

    Peng, Huadong; Li, Hongqiang; Luo, Hao; Xu, Jian

    2013-02-01

    Microcrystalline cellulose (MCC) was performed as a mode substrate to investigate its potential ability of bioconversion in a novel combined pretreatment of ball milling (BM) and/or microwave irradiation (MWI). The variation of structure characteristics of MCC before/after pretreatment were investigated, including crystallinity index (CrI), size of crystal (S(C)), specific surface area (SSA) and degree of polymerization (DP). Their correlation with the rate of enzymatic hydrolysis was differentiated by an optimized equation which indicated the rate of hydrolysis was much more sensitive to CrI than SSA and DP. To achieve the same or higher glucose yield of BM for 3h and 6h, BM for 1h with MWI for 20min could save 54.8% and 77.40% energy consumption, respectively. Moreover, chemicals were not required in this process. It is concluded that the combination of BM and short time MWI is an environment-friendly, economical and effective approach to treat biomass. PMID:23306114

  1. Sewage sludge pretreatment by microwave irradiation combined with activated carbon fibre at alkaline pH for anaerobic digestion.

    PubMed

    Sun, Dedong; Guo, Sixiao; Ma, Nina; Wang, Guowen; Ma, Chun; Hao, Jun; Xue, Mang; Zhang, Xinxin

    2016-01-01

    This research focuses on the effects of microwave-assisted activated carbon fibre (ACF) (MW-ACF) treatment on sewage sludge at alkaline pH. The disintegration and biodegradability of sewage sludge were studied. It was found that the MW-ACF process at alkaline pH provided a rapid and efficient process to disrupt the microbial cells in the sludge. The results suggested that when irradiated at 800 W MW for 110 s with a dose of 1.0 g ACF/g solid concentration (SS) at pH 10.5, the MW-ACF pretreatment achieved 55% SS disintegration, 23% greater than the value of MW alone (32%). The concentration of total nitrogen, total phosphorus, supernatant soluble chemical oxygen demand, protein, and polysaccharide increased by 60%, 144%, 145%, 74%, and 77%, respectively. An increase in biogas production by 63.7% was achieved after 20 days of anaerobic digestion (AD), compared to the control. The results indicated that the MW-ACF pretreatment process at alkaline pH provides novel sludge management options in disintegration of sewage sludge for further AD. PMID:27332832

  2. Highly Sensitive Ethanol Sensor Based on Au-Decorated SnO2 Nanoparticles Synthesized Through Precipitation and Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Li, Yan; Zhao, Fang-Xian; Lian, Xiao-Xue; Zou, Yun-Ling; Wang, Qiong; Zhou, Qing-Jun

    2016-06-01

    Gold (Au)-decorated SnO2 nanoparticles (NPs) were synthesized through a precipitation and microwave irradiation process. The as-prepared products were characterized by x-ray diffraction and scanning electron microscopy. The results indicated that the as-prepared products consisted of nanometer-scale tetragonal crystalline SnO2 and face-centered cubic gold metal NPs. The gas sensing measurements showed that the sensor based on Au-decorated SnO2 NPs exhibited an extremely high response (239.5) toward 500-ppm ethanol at a relatively low working temperature (220°C). In addition, the response and recovery times of this sensor to ethanol were 1 s and 31 s, respectively. The excellent gas sensing performance of the synthesized NPs in terms of high response, fast response-recovery, superior selectivity, and good stability was attributed to the small nanometer size of the particles, Schottky barrier, and Au NP catalysis. Finally, we demonstrated that our Au-decorated SnO2 NPs could be a potential candidate for use in highly sensitive and selective gas sensors for ethanol.

  3. Influence of cetyltrimethylammonium bromide on the morphology of AWO 4 (A = Ca, Sr) prepared by cyclic microwave irradiation

    NASA Astrophysics Data System (ADS)

    Thongtem, Titipun; Kaowphong, Sulawan; Thongtem, Somchai

    2008-09-01

    AWO 4 (A = Ca, Sr) was prepared from metal salts [Ca(NO 3) 2·4H 2O or Sr(NO 3) 2], Na 2WO 4·2H 2O and different moles of cetyltrimethylammonium bromide (CTAB) in water by cyclic microwave irradiation. The structure of AWO 4 was characterized by X-ray diffraction (XRD) and selected area electron diffraction (SAED). Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) revealed the presence of nanoparticles in clusters with different morphologies; spheres, peaches with notches, dumb-bells and bundles, influenced by CTAB. Six Raman vibrational peaks of scheelite structure were detected at 908, 835, 793, 399, 332 and 210 cm -1 for CaWO 4 and 917, 833, 795, 372, 336 and 192 cm -1 for SrWO 4, which are assigned as ν1(A g), ν3(B g), ν3(E g), ν4(B g), ν2(A g) and νf.r.(A g), respectively. Fourier transform infrared (FTIR) spectra provided the evidence of W-O stretching vibration in [WO 4] 2- tetrahedrons at 793 cm -1 for CaWO 4 and 807 cm -1 for SrWO 4. The peaks of photoluminescence (PL) spectra were at 428-434 nm for CaWO 4, and 447-451 nm for SrWO 4.

  4. Synthesis and characterization of wires-like ZnO structures grown on a graphite support by microwave irradiation

    NASA Astrophysics Data System (ADS)

    Mora-Hernández, J. M.; Arce-Estrada, E. M.; Zarazúa-Villalobos, L.; Estrada-Flores, M.; Medina-Flores, J.; Reza-San Germán, C.

    2015-09-01

    Wires-like ZnO structures supported on graphite plates were synthesized by a microwave-assisted method using zinc oxide as precursor which was previously obtained from a chemical oxidation of zinc nitrate hexahydrate. Characterization was made by X-ray diffraction, scanning and high resolution transmission electron microscopy. X-ray diffraction results revealed that homemade ZnO showed the same diffraction peaks as its commercial counterpart, all reflections corresponds to a ZnO wurtzite hexagonal phase. After an irradiation process done at 2.45 GHz and an output power of 1200 W for 7 min, homemade ZnO showed a morphological transformation which can be appreciated in SEM micrographs resulting in the formation of the wires-like ZnO structures; these ones present a broadness between 150 to 200 nm and a variable length from 0.4 to 5 μm. Moreover, energy dispersive spectroscopy reveals that these structures present an entirely elemental zinc oxide composition. Wires-like ZnO structures use carbon plates as a support medium to perform their oriented growing. Finally, high resolution transmission electron microscopy showed that wires-like ZnO structures presents a crystalline arrangement with an interplanar distance of 2.4 Å corresponding to a preferential crystallographic orientation (101).

  5. Novel synthesis of holey reduced graphene oxide (HRGO) by microwave irradiation method for anode in lithium-ion batteries

    PubMed Central

    Alsharaeh, Edreese; Ahmed, Faheem; Aldawsari, Yazeed; Khasawneh, Majdi; Abuhimd, Hatem; Alshahrani, Mohammad

    2016-01-01

    In this work, holey reduced graphene oxide (HRGO) was synthesized by the deposition of silver (Ag) nanoparticles onto the reduced graphene oxide (RGO) sheets followed by nitric acid treatment to remove Ag nanoparticles by microwave irradiation to form a porous structure. The HRGO were characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), ultra violet-visible spectroscopy (UV-Vis), thermogravimetric analysis (TGA), and Raman spectroscopy. These novel HRGO exhibited high rate capability with excellent cycling stability as an anode material for lithium-ion batteries. The results have shown an excellent electrochemical response in terms of charge/discharge capacity (423 mAh/g at 100 mA/g). The cyclic performance was also exceptional as a high reversible capacity (400 mAh/g at 100 mA/g) was retained for 100 charge/discharge cycles. This fascinating electrochemical performance can be ascribed to their specific porous structure (2–5 nm pores) and high surface area (457 m2/g), providing numerous active sites for Li+ insertion, high electrical conductivity, low charge-transfer resistance across the electrolyte–electrode interface, and improved structural stability against the local volume change during Li+ insertion–extraction. Such electrodes are envisioned to be mass scalable with relatively simple and low-cost fabrication procedures, thereby providing a clear pathway toward commercialization. PMID:27457356

  6. Surfactant free rapid synthesis of hydroxyapatite nanorods by a microwave irradiation method for the treatment of bone infection

    NASA Astrophysics Data System (ADS)

    Vani, R.; Bharathi Raja, Subramaniya; Sridevi, T. S.; Savithri, K.; Niranjali Devaraj, S.; Girija, E. K.; Thamizhavel, A.; Narayana Kalkura, S.

    2011-07-01

    Mesoporous nanocrystalline hydroxyapatite (nHAp) rods of size 40-75 nm long and 25 nm wide (resembling bone mineral) were synthesized under microwave irradiation without using any surfactants or modifiers. The surface area and average pore size of the nHAp were found to be 32 m2 g - 1 and 4 nm, respectively. Rifampicin (RIF) and ciprofloxacin (CPF) loaded nHAp displayed an initial burst followed by controlled release (zero order kinetics). Combination of CPF and RIF loaded nHAp showed enhanced bacterial growth inhibition against Staphylococcus aureus (S aureus), Staphylococcus epidermidis (S epidermidis) and Escherichia coli (E coli) compared to individual agent loaded nHAp and pure nHAp. In addition, decreased bacterial adhesion (90%) was observed on the surface of CPF plus RIF loaded nHAp. The biocompatibility test toward MG63 cells infected with micro-organisms showed better cell viability and alkaline phosphatase activity (ALP) for the combination of CPF and RIF loaded nHAp. The influence on cell viability of infected MG63 cells was attributed to the simultaneous and controlled release of CPF and RIF from nHAp, which prevented the emergence of subpopulations that were resistant to each other. Hence, apart from the issue of the rapid synthesis of nHAp without surfactants or modifiers, the simultaneous and controlled release of dual drugs from nHAp would be a simple, non-toxic and cost-effective method to treat bone infections.

  7. Effect of extracorporeal ultraviolet blood irradiation on blood cholesterol level

    NASA Astrophysics Data System (ADS)

    Zalesskaya, G. A.; Laskina, O. V.; Mitkovskaya, N. P.; Kirkovsky, V. V.

    2012-07-01

    We have studied the effect of extracorporeal ultraviolet blood irradiation on cholesterol metabolism in patients with cardiovascular diseases. We have carried out a comprehensive analysis of the spectral characteristics of blood and plasma, gas-exchange and oximetry parameters, and the results of a complete blood count and chemistry panel before and after UV blood irradiation. We have assessed the changes in concentrations of cholesterols (total cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides) in the blood of the patients in response to a five-day course of UV blood irradiation. The changes in the spectral characteristics of blood and plasma, the chemistry panel, the gas composition, and the fractional hemoglobin composition initiated by absorption of UV radiation are used to discuss the molecular mechanisms for the effect of therapeutic doses of UV radiation on blood cholesterols.

  8. Afferent mechanisms of microwave-induced biological effects. Final report, June 1980-August 1987

    SciTech Connect

    Lai, H.; Horita, A.; Chou, C.K.; Guy, A.W.

    1987-08-12

    Effects of low-level microwave irradiation on neurological function were investigated in the rat. Results can be summarized in the following statements: (1) acute exposure effects the response of an animal to psychoactive drugs and changes cholinergic activity in the brain; (2) effects of microwaves are classically conditionable to environmental cues after repeated exposure. Tolerance can also develop after repeated exposure; and (3) endogenous opioids play a mediating role in certain neurological effects of microwaves. These data further our understanding on the neurological effects of microwave exposure and may have important implications in certain occupational situations in which repeated exposure to low-level microwaves is unavoidable.

  9. Circuit-level simulation of transistor lasers and its application to modelling of microwave photonic links

    NASA Astrophysics Data System (ADS)

    Iezekiel, Stavros; Christou, Andreas

    2015-03-01

    Equivalent circuit models of a transistor laser are used to investigate the suitability of this relatively new device for analog microwave photonic links. The three-terminal nature of the device enables transistor-based circuit design techniques to be applied to optoelectronic transmitter design. To this end, we investigate the application of balanced microwave amplifier topologies in order to enable low-noise links to be realized with reduced intermodulation distortion and improved RF impedance matching compared to conventional microwave photonic links.

  10. Microwave-assisted combustion synthesis of Ag/ZnO nanocomposites and their photocatalytic activities under ultraviolet and visible-light irradiation

    SciTech Connect

    Zhang, Dafeng; Pu, Xipeng; Li, Huaiyong; Yu, Young Moon; Shim, Jae Jeong; Cai, Peiqing; Kim, Sun Il; Seo, Hyo Jin

    2015-01-15

    Highlights: • Ag/ZnO nanocomposites were synthesized by a microwave-assisted combustion method. • Ag/ZnO nanocomposites exhibited improved photocatalytic activities under UV irradiation. • Poorer photocatalytic performances were obtained under visible-light irradiation. - Abstract: Ag/ZnO nanocomposites were synthesized by a rapid one-step microwave-assisted combustion method. The as-synthesized samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, photoluminescence and ultraviolet–visible spectrophotometry. XRD results showed that hexagonal ZnO and cubic Ag were obtained. Ag nanoparticles were chemically attached on the surface of ZnO. The decrease in the energy band gap of Ag/ZnO nanocomposites and the photoluminescence quenching were observed while the Ag content was increased. Furthermore, the introduction of Ag nanoparticles leads to significantly improved photocatalytic activities in the case of ultraviolet irradiation, but in the case of visible-light irradiation opposite results were obtained. The corresponding mechanism was discussed in detail.

  11. Effects of ionic conduction on hydrothermal hydrolysis of corn starch and crystalline cellulose induced by microwave irradiation.

    PubMed

    Tsubaki, Shuntaro; Oono, Kiriyo; Onda, Ayumu; Yanagisawa, Kazumichi; Mitani, Tomohiko; Azuma, Jun-ichi

    2016-02-10

    This study investigated the effects of ionic conduction of electrolytes under microwave field to facilitate hydrothermal hydrolysis of corn starch and crystalline cellulose (Avicel), typical model biomass substrates. Addition of 0.1M NaCl was effective to improve reducing sugar yield by 1.61-fold at unit energy (kJ) level. Although Avicel cellulose was highly recalcitrant to hydrothermal hydrolysis, addition of 0.1M MgCl2 improved reducing sugar yield by 6.94-fold at unit energy (kJ). Dielectric measurement of the mixture of corn starch/water/electrolyte revealed that ionic conduction of electrolytes were strongly involved in facilitating hydrothermal hydrolysis of polysaccharides. PMID:26686168

  12. Control of spontaneous emission from a microwave-field-coupled three-level{Lambda}-type atom in photonic crystals

    SciTech Connect

    Jiang, X. Q.; Zhang, B.; Sun, X. D.; Lu, Z. W.

    2011-05-15

    The spontaneous emission spectrum of a three-level {Lambda}-type atom driven by a microwave field was studied. For the two transitions coupled to the same modified reservoir, we discussed the influence of photonic band gap and Rabi frequency of the microwave field on the emission spectrum. The emission spectrum is given for different locations of the upper band-edge frequency. With the transition frequencies moving from outside the band gap to inside, the number of peaks decreases in the emission spectrum and the multipeak structure of spectral line is finally replaced by a strong non-Lorentzian shape. With increase of the Rabi frequency of the microwave field, we find the spectral line changes from a multipeak structure to a two-peak structure, originating from the inhibition of spontaneous emission for the corresponding decay channel.

  13. Foliar anatomical and morphological variation in Nothofagus pumilio seedlings under controlled irradiance and soil moisture levels.

    PubMed

    Ivancich, Horacio S; Lencinas, María V; Pastur, Guillermo J Martínez; Esteban, Rosina M Soler; Hernández, Luis; Lindstrom, Ivone

    2012-05-01

    Foliar anatomy and morphology are strongly related to physiological performance; therefore, phenotypic plasticity in leaves to variations in environmental conditions, such as irradiance and soil moisture availability, can be related to growth rate and survivorship, mainly during critical growth phases, such as establishment. The aim of this work was to analyze changes in the foliar internal anatomy (tissue proportions and cell dimensions) and external morphology (leaf length, width and area) of Nothofagus pumilio (Poepp. et Endl.) Krasser seedlings growing in a greenhouse under controlled irradiance (three levels) and soil moisture (two levels) during one growing season (measured three times), and to relate them to physiological traits. Three irradiance levels (4, 26 and 64% of the natural incident light) and two soil moisture levels (40 and 80% soil capacity) were evaluated during November, January and March. Internal foliar anatomy of seedlings was analyzed using digital photographs of histological cuttings, while leaf gross morphology was measured using digital calipers and image analysis software. Most internal anatomical variables presented significant differences under different irradiance levels during the growing season, but differences were not detected between soil moisture levels. Palisade parenchyma was the tissue most sensitive to irradiance levels, and high irradiance levels (64% natural incident light) produced greater values in most of the internal anatomical variables than lower irradiance levels (4-24% natural incident light). Complementarily, larger leaves were observed in medium and low irradiance levels, as well as under low soil moisture levels (40% soil capacity). The relationship of main results with some eco-physiological traits was discussed. Foliar internal anatomical and external morphological plasticity allows quick acclimation of seedlings to environmental changes (e.g., during harvesting). These results can be used to propose new

  14. Fabrication of high-performance ultra-thin-body SnO{sub 2} thin-film transistors using microwave-irradiation post-deposition annealing

    SciTech Connect

    Jo, Kwang-Won; Moon, Sung-Wan; Cho, Won-Ju

    2015-01-26

    We report on the fabrication of high-performance ultra-thin-body (UTB) SnO{sub 2} thin-film transistors (TFTs) using microwave-irradiation post-deposition annealing (PDA) at a low process temperature (<100 °C). We confirm that the electrical characteristics of SnO{sub 2} TFTs become drastically enhanced below a body thickness of 10 nm. The microwave-annealed UTB SnO{sub 2} TFTs with a thickness of 5 nm exhibited increased optical transmittance, as well as remarkable transfer characteristics: a high mobility of 35.4 cm{sup 2} V{sup −1} s{sup −1}, a drain current on/off ratio of 4.5 × 10{sup 7}, a steep subthreshold gate voltage swing of 623 mV/dec, and a clear enhancement-mode behavior. Additionally, the microwave-annealed SnO{sub 2} TFTs exhibited a better positive gate-bias stress/negative gate-bias stress immunity than thermally annealed SnO{sub 2} TFTs. Therefore, the thickness of the UTB SnO{sub 2} TFTs, as well as the microwave-annealing process, are both shown to be essential for transparent and flexible display technology.

  15. Dynamics of a three-level V-type atom driven by a cavity photon and microwave field

    NASA Astrophysics Data System (ADS)

    Yan-Li, Xue; Shi-Deng, Zhu; Ju, Liu; Ting-Hui, Xiao; Bao-Hua, Feng; Zhi-Yuan, Li

    2016-04-01

    We discuss the dynamics of a three-level V-type atom driven simultaneously by a cavity photon and microwave field by examining the atomic population evolution. Owing to the coupling effect of the cavity photon, periodical oscillation of the population between the two upper states and the ground state takes place, which is the well-known vacuum Rabi oscillation. Meanwhile, the population exchange between the upmost level and the middle level can occur due to the driving action of the external microwave field. The general dynamic behavior is the superposition of a fast and a slow periodical oscillation under the cooperative and competitive effect of the cavity photon and the microwave field. Numerical results demonstrate that the time evolution of the population is strongly dependent on the atom–cavity coupling coefficient g and Rabi frequency Ω e that reflects the intensity of the external microwave field. By modulating the two parameters g and Ω e, a large number of population transfer behaviors can be achieved. Project supported by the National Natural Science Foundation of China (Grant Nos. 11434017 and 11374357) and the National Basics Research Program of China (Grant No. 2013CB632704).

  16. Central nervous system transplantation benefited by low-level laser irradiation

    NASA Astrophysics Data System (ADS)

    Rochkind, S.; Lubart, Rachel; Wollman, Yoram; Simantov, Rabi; Nissan, Moshe; Barr-Nea, Lilian

    1990-06-01

    Effect of low-level laser irradiation on the central nervous system transplantation is reported. Ernbryonal brain allografts were transplanted into the brain of 20 adult rats and peripheral nerve graft transplanted into the severely injured spinal cord of 16 dogs. The operated wound of 10 rats and 8 dogs were exposed daily for 21 days to lowpower laser irradiation CW HeNe laser (35 mW, 632.8 run, energy density of 30 J/cm2 at each point for rats and 70 J/cm2 at each point for dogs). This study shows that (i) the low-level laser irradiation prevents extensive glial scar formation (a limiting factor in CNS regeneration) between embryonal transplants and host brain; (ii) Dogs made paraplegic by spinal cord injury were able to walk 3-6 months later. Recovery of these dogs was effected by the implantation of a fragment of autologous sciatic nerve at the site of injury and subsequently exposing the dogs to low-level laser irradiation. The effect of laser irradiation on the embryonal nerve cells grown in tissue culture was also observed. We found that low-level laser irradiation induced intensive migration of neurites outward of the aggregates 15-22 The results of the present study and our previous investigations suggest that low-level laser irradiation is a novel tool for treatment of peripheral and central nervous system injuries.

  17. Level crossing analysis of cosmic microwave background radiation: a method for detecting cosmic strings

    SciTech Connect

    Movahed, M. Sadegh; Khosravi, Shahram E-mail: khosravi@ipm.ir

    2011-03-01

    In this paper we study the footprint of cosmic string as the topological defects in the very early universe on the cosmic microwave background radiation. We develop the method of level crossing analysis in the context of the well-known Kaiser-Stebbins phenomenon for exploring the signature of cosmic strings. We simulate a Gaussian map by using the best fit parameter given by WMAP-7 and then superimpose cosmic strings effects on it as an incoherent and active fluctuations. In order to investigate the capability of our method to detect the cosmic strings for the various values of tension, Gμ, a simulated pure Gaussian map is compared with that of including cosmic strings. Based on the level crossing analysis, the superimposed cosmic string with Gμ∼>4 × 10{sup −9} in the simulated map without instrumental noise and the resolution R = 1' could be detected. In the presence of anticipated instrumental noise the lower bound increases just up to Gμ∼>5.8 × 10{sup −9}.

  18. Microwave short-pulse bed-level detector. Annual report, January 1-December 31, 1981

    SciTech Connect

    Balanis, C.A.; Delauder, D.M.

    1981-01-01

    A short-pulse microwave system for measuring the bed-level within a fluidized-bed combustor, has been designed, built, and laboratory tested on static beds. The system is a short-pulse radar which operates in the frequency region of 6.75 to 10.95 GHz as a time-domain measurement system. Laboratory measurements of static bed-levels, for smooth and corrugated surfaces of metal plates and limestone sand, agree to an average of 2.0% of the actual heights. Additionally, the system was tested with a dielectric thermal protector, which did not compromise the accuracy of the measurements. Analytical models have been formulated to provide insight into the operation of the system on a wide range of simulated targets without the necessity of performing expensive and difficult laboratory experiments. Two formulations have been used to describe electromagnetic scattering by a rough surface as a function of frequency: the space harmonic model and the physical optics model. A reconstruction technique has been devised which uses the scattering models and the spectrum of the transmitted pulse to synthesize the reflected pulse. The data generated by the models compare well to previously published data and to experimental results.

  19. Towards microwave imaging of single two-level defects in dielectric materials

    NASA Astrophysics Data System (ADS)

    de Graaf, Sebastian; Danilov, Andrey; Tzalenchuk, Alexander; Kubatkin, Sergey

    Two-level fluctuators (TLF) are a major source of decoherence in quantum devices and significant effort is invested towards better understanding and eliminating these types of material defects. Here we propose that a near-field scanning microwave microscope (NSMM) can be used to image individual two-level defects on the nano-scale, provided that such a microscope operates in the right regime. Not only would such a 'coherent' NSMM be able to obtain nano-scale spatial distributions of defects and their locations within dielectric materials, it would also be able to determine the relative orientation of the TLF dipole with respect to the dielectric crystal, giving vital information about the nature of the TLF. We theoretically describe the operation and capabilities of a 'coherent' NSMM and show that individual defects can be imaged in dielectric materials with low enough loss tangent, such as sapphire and silicon dioxide, relevant for solid state quantum technologies. We describe the requirements for constructing such an NSMM and report on our recent progress in setting up this technology.

  20. Acute UV irradiation increases heparan sulfate proteoglycan levels in human skin.

    PubMed

    Jung, Ji-Yong; Oh, Jang-Hee; Kim, Yeon Kyung; Shin, Mi Hee; Lee, Dayae; Chung, Jin Ho

    2012-03-01

    Glycosaminoglycans are important structural components in the skin and exist as various proteoglycan forms, except hyaluronic acid. Heparan sulfate (HS), one of the glycosaminoglycans, is composed of repeated disaccharide units, which are glucuronic acids linked to an N-acetyl-glucosamine or its sulfated forms. To investigate acute ultraviolet (UV)-induced changes of HS and HS proteoglycans (HSPGs), changes in levels of HS and several HSPGs in male human buttock skin were examined by immunohistochemistry and real-time quantitative polymerase chain reaction (qPCR) after 2 minimal erythema doses (MED) of UV irradiation (each n = 4-7). HS staining revealed that 2 MED of UV irradiation increased its expression, and staining for perlecan, syndecan-1, syndecan-4, CD44v3, and CD44 showed that UV irradiation increased their protein levels. However, analysis by real-time qPCR showed that UV irradiation did not change mRNA levels of CD44 and agrin, and decreased perlecan and syndecan-4 mRNA levels, while increased syndecan-1 mRNA level. As HS-synthesizing or -degrading enzymes, exostosin-1 and heparanase mRNA levels were increased, but exostosin-2 was decreased by UV irradiation. UV-induced matrix metalloproteinase-1 expression was confirmed for proper experimental conditions. Acute UV irradiation increases HS and HSPG levels in human skin, but their increase may not be mediated through their transcriptional regulation. PMID:22379342

  1. Level-crossing enhancement of the microwave ionization of highly excited hydrogen atoms

    SciTech Connect

    Bayfield, J.E.; Luie, S.Y.

    1993-05-01

    For quasi one-dimensional atoms, we have observed oscillatory ionization probability as a function of microwave field strength, well below the threshold for classical chaos. This occurs within the microwave/Kepler frequency ratio rage 0.45-0.56. A Landau-Zener model modified to include ionizations of one quasienergy eigenstate can fit the data, there are Stuckelberg oscillations arising from occurring during the rise and fall of pulse. Varying the principal quantum number of the atom reveals a large degree of classical scaling, indicating that the quasienergy states involved are largely semiclassical. Observable changes in the data can result from a 0.2% change in microwave frequency.

  2. Development, Test, and Evaluation of Microwave Radar Water Level (MWWL) Sensors' Wave Measurement Capability

    NASA Astrophysics Data System (ADS)

    Iyer, S. K.; Heitsenrether, R.

    2015-12-01

    Waves can have a significant impact on many coastal operations including navigational safety, recreation, and even the economy. Despite this, as of 2009, there were only 181 in situ real-time wave observation networks nationwide (IOOS 2009). There has recently been interest in adding real-time wave measurement systems to already existing NOAA Center for Operational Oceanographic Products and Services (CO-OPS) stations. Several steps have already been taken in order to achieve this, such as integrating information from existing wave measurement buoys and initial testing of multiple different wave measurement systems (Heitsenrether et al. 2012). Since wave observations can be derived from high frequency water level changes, we will investigate water level sensors' capability to measure waves. Recently, CO-OPS has been transitioning to new microwave radar water level (MWWL) sensors which have higher resolution and theoretically a greater potential wave measurement capability than the acoustic sensors in stilling wells. In this study, we analyze the wave measurement capability of MWWL sensors at two high energy wave environments, Duck, NC and La Jolla, CA, and compare results to two "reference" sensors (A Nortek acoustic waves and currents profiler (AWAC) at Duck and a single point pressure sensor at La Jolla). A summary of results from the two field test sites will be presented, including comparisons of wave energy spectra, significant wave height, and peak period measured by the test MWWL sensors and both reference AWAC and pressure sensors. In addition, relationships between MWWL versus reference wave sensor differences and specific wave conditions will be discussed. Initial results from spectral analysis and the calculation of bulk wave parameters indicate that MWWL sensors set to the "NoFilter" processing setting can produce wave measurements capability that compare well to the two reference sensors. These results support continued development to enable the

  3. Controllable microwave three-wave mixing via a single three-level superconducting quantum circuit.

    PubMed

    Liu, Yu-xi; Sun, Hui-Chen; Peng, Z H; Miranowicz, Adam; Tsai, J S; Nori, Franco

    2014-01-01

    Three-wave mixing in second-order nonlinear optical processes cannot occur in atomic systems due to the electric-dipole selection rules. In contrast, we demonstrate that second-order nonlinear processes can occur in a superconducting quantum circuit (i.e., a superconducting artificial atom) when the inversion symmetry of the potential energy is broken by simply changing the applied magnetic flux. In particular, we show that difference- and sum-frequencies (and second harmonics) can be generated in the microwave regime in a controllable manner by using a single three-level superconducting flux quantum circuit (SFQC). For our proposed parameters, the frequency tunability of this circuit can be achieved in the range of about 17 GHz for the sum-frequency generation, and around 42 GHz (or 26 GHz) for the difference-frequency generation. Our proposal provides a simple method to generate second-order nonlinear processes within current experimental parameters of SFQCs. PMID:25487352

  4. Selective oxidation of rhodinol to citral using H{sub 2}O{sub 2}-platinum black system under microwave irradiation

    SciTech Connect

    Chong, D. J. W.; Latip, J.; Hasbullah, S. A.; Sastrohamidjojo, H.

    2014-09-03

    The oxidation method utilising H{sub 2}O{sub 2}-Pt black system was successfully adapted in the oxidation of rhodinol which is a mixture form of geraniol and citronellol. This green oxidation found to be selectively converted geraniol to citral using conventional method. The implementation of microwave irradiation (175 Watt, 90°C, 30 mins) and a higher molar of H{sub 2}O{sub 2} further improved the conversion rate (72.6%) and selectivity (81%) as compared to the conventional method.

  5. Expression of fas protein on CD4+T cells irradiated by low level He-Ne

    NASA Astrophysics Data System (ADS)

    Nie, Fan; Zhu, Jing; Zhang, Hui-Guo

    2005-07-01

    Objective: To investigate the influence on the Expression of Fas protein on CD4+ T cells irradiated by low level He-Ne laser in the cases of psoriasis. Methods:the expression of CD4+ T Fas protein was determined in the casee of psoriasis(n=5) pre and post-low level laser irradiation(30 min、60min and 120min)by flow cytometry as compared withthe control(n=5). Results:In the cases of psoriasis,the expression of CD4+T FAS protein 21.4+/-3.1% was increased significantly than that of control group 16.8+/-2.1% pre-irradiation, p<0.05in the control,there is no difference between pre and post- irradiation,p>0.05in the cases , the expression of CD4+T Fas protein wae positively corelated to the irradiation times, when the energy density arrived to 22.92J/cm2(60 minutes)and 45.84J/cm2(120minutes), the expression of CD4+ T Fas protein was increased significantly as compared with pre-irradiation,p<0.05.Conclusion: The expression of CD4+T Fas protein may be increased by low level He-Ne laser irradiation ,the uncontrolled status of apoptosis could be corrected.

  6. Scalable Microwave Addressing of Trapped Ion Qubits at Fault-tolerant Error Levels

    NASA Astrophysics Data System (ADS)

    Prado Lopes Aude Craik, Diana; Linke, Norbert; Allcock, David; Harty, Thomas; Sepiol, Martin; Stacey, Derek; Steane, Andrew; Lucas, David

    2015-05-01

    We present results obtained with a two-zone, scalable prototype surface-electrode ion trap for storing and individually addressing memory qubits. The trap has 4 integrated microwave electrodes per zone, designed to provide enough degrees of freedom for independent, parallel control of the microwave field amplitude, phase and polarization at each ion. In a demonstration experiment, we use two trap electrodes, one in each zone, to drive Rabi flops in a Calcium-43 ion trapped in the zone we wish to address, while nulling the microwave field in the neighbor zone. We measure Rabi frequency ratios between the addressed and nulled zones of up to 1400, implying that spin-flip errors of order 10-6 are achievable. We also demonstrate polarization control of the microwave field by selectively driving one of two near-degenerate transitions out of the qubit states, one of which is driven by σ+ polarization and the other by σ- polarization. We null the σ+ component of the microwave field at the ion and measure a Rabi frequency ratio of ~ 350 between the σ- and σ+ transitions. Finally, a new design concept for scalable microwave surface-electrode ion traps is presented and progress on the next-generation prototype is reported. This work is supported by the US Army Research Office, EPSRC (UK) and the UK National Quantum Technologies Programme.

  7. New type of B-periodic magneto-oscillations in a two-dimensional electron system induced by microwave irradiation.

    PubMed

    Kukushkin, I V; Akimov, M Yu; Smet, J H; Mikhailov, S A; von Klitzing, K; Aleiner, I L; Falko, V I

    2004-06-11

    We observe a new type of magneto-oscillations in the photovoltage and the longitudinal resistance of a two-dimensional electron system. The oscillations are induced by microwave radiation and are periodic in magnetic field. The period is determined by the microwave frequency, the electron density, and the distance between potential probes. The phenomenon is accounted for by interference of coherently excited edge magnetoplasmons in the contact regions and offers perspectives for developing new tunable microwave and terahertz detection schemes and spectroscopic techniques. PMID:15245184

  8. Optimization of bio-diesel production from soybean and wastes of cooked oil: combining dielectric microwave irradiation and a SrO catalyst.

    PubMed

    Koberg, Miri; Abu-Much, Riam; Gedanken, Aharon

    2011-01-01

    This work offers an optimized method in the transesterification of pristine (soybean) oil and cooked oil to bio-diesel, based on microwave dielectric irradiation as a driving force for the transesterification reaction and SrO as a catalyst. This combination has demonstrated excellent catalytic activity and stability. The transesterification was carried out with and without stirring. According to 1H NMR spectroscopy and TLC results, this combination accelerates the reaction (to less than 60 s), maintaining a very high conversion (99%) and high efficiency. The catalytic activity of SrO under atmospheric pressure in the presence of air and under the argon atmosphere is demonstrated. The optimum conversion of cooked oil (99.8%) is achieved under MW irradiation of 1100 W output with magnetic stirring after only 10 s. The optimum method decreases the cost of bio-diesel production and has the potential for industrial application in the transesterification of cooked oil to bio-diesel. PMID:20833538

  9. An experimental model to determine the level of antibiotics in irradiated tissues

    SciTech Connect

    Cruz, N.I.; Ariyan, S.; Miniter, P.; Andriole, V.T.

    1984-05-01

    An experimental study was designed using male Sprague-Dawley rats treated with a single dose of 1800 rads to an area of skin and soft tissue of the back measuring 2 X 3 cm. This dose was estimated to produce changes equivalent to 6000 rads in divided doses over 6 weeks. At intervals of 5, 10, and 15 weeks after irradiation, punch biopsies were taken from both irradiation, and nonirradiated skin areas of each animal 30 minutes after the intraperitoneal administration of gentamicin. Skin homogenates were prepared, and the antibiotic levels in these samples were determined by a bacterial growth inhibition assay. The antibiotic levels were found to be equal (16.1 +/- 6 micrograms/ml vs. 16.0 +/- 5 micrograms/ml) in both irradiated and nonirradiated skin at 5 weeks after radiation. However, at 10 and 15 weeks after radiation, the antibiotic levels had dropped to 9.9 +/- 3 micrograms/ml in irradiated skin compared with 14.1 +/- 4 micrograms/ml in normal skin (p less than 0.001) and with 5.4 micrograms/ml in irradiated skin vs. 11.8 +/- 5 micrograms/ml in nonirradiated skin (p less than 0.001), respectively. Results demonstrate that in spite of adequate gentamicin levels in the circulation and nonirradiated tissue in rats, gentamicin has a decreasing ability to diffuse into irradiated tissues with increasing intervals after therapeutic doses of radiation.

  10. Single microwave-photon detector using an artificial Λ-type three-level system.

    PubMed

    Inomata, Kunihiro; Lin, Zhirong; Koshino, Kazuki; Oliver, William D; Tsai, Jaw-Shen; Yamamoto, Tsuyoshi; Nakamura, Yasunobu

    2016-01-01

    Single-photon detection is a requisite technique in quantum-optics experiments in both the optical and the microwave domains. However, the energy of microwave quanta are four to five orders of magnitude less than their optical counterpart, making the efficient detection of single microwave photons extremely challenging. Here we demonstrate the detection of a single microwave photon propagating through a waveguide. The detector is implemented with an impedance-matched artificial Λ system comprising the dressed states of a driven superconducting qubit coupled to a microwave resonator. Each signal photon deterministically induces a Raman transition in the Λ system and excites the qubit. The subsequent dispersive readout of the qubit produces a discrete 'click'. We attain a high single-photon-detection efficiency of 0.66±0.06 with a low dark-count probability of 0.014±0.001 and a reset time of ∼400 ns. This detector can be exploited for various applications in quantum sensing, quantum communication and quantum information processing. PMID:27453153

  11. Single microwave-photon detector using an artificial Λ-type three-level system

    PubMed Central

    Inomata, Kunihiro; Lin, Zhirong; Koshino, Kazuki; Oliver, William D.; Tsai, Jaw-Shen; Yamamoto, Tsuyoshi; Nakamura, Yasunobu

    2016-01-01

    Single-photon detection is a requisite technique in quantum-optics experiments in both the optical and the microwave domains. However, the energy of microwave quanta are four to five orders of magnitude less than their optical counterpart, making the efficient detection of single microwave photons extremely challenging. Here we demonstrate the detection of a single microwave photon propagating through a waveguide. The detector is implemented with an impedance-matched artificial Λ system comprising the dressed states of a driven superconducting qubit coupled to a microwave resonator. Each signal photon deterministically induces a Raman transition in the Λ system and excites the qubit. The subsequent dispersive readout of the qubit produces a discrete ‘click'. We attain a high single-photon-detection efficiency of 0.66±0.06 with a low dark-count probability of 0.014±0.001 and a reset time of ∼400 ns. This detector can be exploited for various applications in quantum sensing, quantum communication and quantum information processing. PMID:27453153

  12. Single microwave-photon detector using an artificial Λ-type three-level system

    NASA Astrophysics Data System (ADS)

    Inomata, Kunihiro; Lin, Zhirong; Koshino, Kazuki; Oliver, William D.; Tsai, Jaw-Shen; Yamamoto, Tsuyoshi; Nakamura, Yasunobu

    2016-07-01

    Single-photon detection is a requisite technique in quantum-optics experiments in both the optical and the microwave domains. However, the energy of microwave quanta are four to five orders of magnitude less than their optical counterpart, making the efficient detection of single microwave photons extremely challenging. Here we demonstrate the detection of a single microwave photon propagating through a waveguide. The detector is implemented with an impedance-matched artificial Λ system comprising the dressed states of a driven superconducting qubit coupled to a microwave resonator. Each signal photon deterministically induces a Raman transition in the Λ system and excites the qubit. The subsequent dispersive readout of the qubit produces a discrete `click'. We attain a high single-photon-detection efficiency of 0.66+/-0.06 with a low dark-count probability of 0.014+/-0.001 and a reset time of ~400 ns. This detector can be exploited for various applications in quantum sensing, quantum communication and quantum information processing.

  13. Biodiesel production from lipids in wet microalgae with microwave irradiation and bio-crude production from algal residue through hydrothermal liquefaction.

    PubMed

    Cheng, Jun; Huang, Rui; Yu, Tao; Li, Tao; Zhou, Junhu; Cen, Kefa

    2014-01-01

    A cogeneration process of biodiesel and bio-crude was proposed to make full use of wet microalgae biomass. High-grade biodiesel was first produced from lipids in wet microalgae through extraction and transesterification with microwave irradiation. Then, low-grade bio-crude was produced from proteins and carbohydrates in the algal residue through hydrothermal liquefaction. The total yield (40.19%) and the total energy recovery (67.73%) of the cogenerated biodiesel and bio-crude were almost equal to those of the bio-oil obtained from raw microalgae through direct hydrothermal liquefaction. Upon microwave irradiation, proteins were partially hydrolyzed and the hydrolysates were apt for deaminization under the hydrothermal condition of the algal residue. Hence, the total remaining nitrogen (16.02%) in the cogenerated biodiesel and bio-crude was lower than that (27.06%) in the bio-oil. The cogeneration process prevented lipids and proteins from reacting to produce low-grade amides and other long-chain nitrogen compounds during the direct hydrothermal liquefaction of microalgae. PMID:24183493

  14. Nano-composite of poly(L-lactide) and halloysite nanotubes surface-grafted with L-lactide oligomer under microwave irradiation.

    PubMed

    Luo, Bing-Hong; Hsu, Chung-En; Li, Jian-Hua; Zhao, Liang-Feng; Liu, Ming-Xian; Wang, Xiao-Ying; Zhou, Chang-Ren

    2013-04-01

    In order to improve the bonding between halloysite nanotubes (HNTs) and poly(L-lactide) (PLLA), and hence to increase the mechanical properties of HNTs/PLLA nano-composite, HNTs were surface-grafted with PLLA under microwave irradiation and then blended with PLLA matrix. The optimal conditions for grafting polymerization are: irradiation time of 30 min, microwave power of 30 W and reaction temperature of 130 degrees C. The structure and properties of the surface-grafted HNTs (g-HNTs) were characterized by Fourier transformation infrared (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and dynamic light scattering (DLS). Nano-composites of g-HNTs/PLLA and non-grafted HNTs/PLLA were subsequently evaluated in terms of crystallinity, dispersion, interfacial interaction, mechanical performance and cytocompatibility by polarized optical microscopy (POM), field scanning electron microscope (FESM), tensile testing and cell culture experiment. Results show that the grafted PLLA chains on the surfaces of HNTs, as inter-tying molecules, played an important role in improving the adhesive strength between the nanotubes and the polymer matrix. The enhanced interaction among g-HNTs and PLLA matrix resulted in a better tensile strength and modulus compared to the pristine PLLA and HNTs/PLLA. Cell culture results indicated that g-HNTs promoted both adhesion and proliferation of M3T3 fibroblasts on the g-HNTs/PLLA composite film. PMID:23621025

  15. Conversion of fructose and glucose into 5-hydroxymethylfurfural with lignin-derived carbonaceous catalyst under microwave irradiation in dimethyl sulfoxide-ionic liquid mixtures.

    PubMed

    Guo, Feng; Fang, Zhen; Zhou, Tie-Jun

    2012-05-01

    5-Hydroxymethylfurfural (5-HMF) was successfully produced by the dehydration of fructose and glucose using lignin-derived solid acid catalyst in DMSO-[BMIM][Cl] (dimethyl sulfoxide and 1-butyl-3-methylimidazolium chloride) mixtures. Six solid acid catalysts were synthesized by carbonization and sulfonation of raw biomass materials, i.e., glucose, fructose, cellulose, lignin, bamboo and Jatropha hulls. It was found that lignin-derived solid acid catalyst (LCC) was the most active one in the dehydration of sugars. LCC coupled with microwave irradiation was used for the 5-HMF production, 84% 5-HMF yield with 98% fructose conversion rate was achieved at 110°C for 10 min. Furthermore, 99% glucose was converted with 68% 5-HMF yield under severer condition (160°C for 50 min). LCC was recycled for five times, 5-HMF yield declined only 7%. Use of LCC combined with DMSO-[BMIM][Cl] solution and microwave irradiation is a novel method for the effective production of 5-HMF. PMID:22429401

  16. Microwave heating for production of a glass bonded ceramic high-level waste form.

    SciTech Connect

    O'Holleran, T. P.

    2002-07-30

    Argonne National Laboratory has developed a ceramic waste form to immobilize the salt waste from electrometallurgical treatment of spent nuclear fuel. The process is being scaled up to produce bodies of 100 Kg or greater. With conventional heating, heat transfer through the starting powder mixture necessitates long process times. Coupling of 2.45 GHz radiation to the starting powders has been demonstrated. The radiation couples most strongly to the salt occluded zeolite powder. The results of these experiments suggest that this ceramic waste form could be produced using microwave heating alone, or by using microwave heating to augment conventional heating.

  17. Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models.

    PubMed

    Brendtke, Rico; Wiehl, Michael; Groeber, Florian; Schwarz, Thomas; Walles, Heike; Hansmann, Jan

    2016-01-01

    Tissue dehydration results in three major types of exsiccosis--hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring. PMID:27046226

  18. Feasibility Study on a Microwave-Based Sensor for Measuring Hydration Level Using Human Skin Models

    PubMed Central

    Brendtke, Rico; Wiehl, Michael; Groeber, Florian; Schwarz, Thomas; Walles, Heike; Hansmann, Jan

    2016-01-01

    Tissue dehydration results in three major types of exsiccosis—hyper-, hypo-, or isonatraemia. All three types entail alterations of salt concentrations leading to impaired biochemical processes, and can finally cause severe morbidity. The aim of our study was to demonstrate the feasibility of a microwave-based sensor technology for the non-invasive measurement of the hydration status. Electromagnetic waves at high frequencies interact with molecules, especially water. Hence, if a sample contains free water molecules, this can be detected in a reflected microwave signal. To develop the sensor system, human three-dimensional skin equivalents were instituted as a standardized test platform mimicking reproducible exsiccosis scenarios. Therefore, skin equivalents with a specific hydration and density of matrix components were generated and microwave measurements were performed. Hydration-specific spectra allowed deriving the hydration state of the skin models. A further advantage of the skin equivalents was the characterization of the impact of distinct skin components on the measured signals to investigate mechanisms of signal generation. The results demonstrate the feasibility of a non-invasive microwave-based hydration sensor technology. The sensor bears potential to be integrated in a wearable medical device for personal health monitoring. PMID:27046226

  19. Variation in cyclic nucleotide levels and lysosomal enzyme activities in the irradiated rat

    SciTech Connect

    Trocha, P.J.; Catravas, G.N.

    1980-09-01

    Whole-body irradiation of rats causes not only a release of hydrolases from the lysosomes but also fluctuations in the cyclic nucleotide levels in spleen and liver tissues. Significant increases in lysosomal enzyme activities were further observed in spleen following radiation treatment. At 3 to 6 hr after rats were exposed to ..gamma.. radiation, transient increases in both cGMP and cAMP levels were accompanied with the release of ..beta..-glucuronidase and acid phosphatase enzymes from lysosomes in liver and spleen tissues. A second transitory release and activation of lysosomal hydrolases and an increase in cAMP levels occurred between 2 and 5 days after irradiation in spleen but not in liver. On Days 7 and 8, there was a third release of lysosomal hydrolases and a slight increase in the spleen cAMP concentration before they returned to near-control values. Cyclic GMP levels in the spleen decreased on the third day after irradiation, remained suppressed until Day 9, and then increased to levels higher than normal physiological values. The liver cGMP concentration remained unchanged between 9 hr and 11 days after irradiation.

  20. Color-Controlled Ag Nanoparticles and Nanorods within Confined Mesopores: Microwave-Assisted Rapid Synthesis and Application in Plasmonic Catalysis under Visible-Light Irradiation.

    PubMed

    Mori, Kohsuke; Verma, Priyanka; Hayashi, Ryunosuke; Fuku, Kojirou; Yamashita, Hiromi

    2015-08-10

    Color-controlled spherical Ag nanoparticles (NPs) and nanorods, with features that originate from their particle sizes and morphologies, can be synthesized within the mesoporous structure of SBA-15 by the rapid and uniform microwave (MW)-assisted alcohol reduction method in the absence or presence of surface-modifying organic ligands. The obtained several Ag catalysts exhibit different catalytic activities in the H2 production from ammonia borane (NH3 BH3 , AB) under dark conditions, and higher catalytic activity is observed by smaller yellow Ag NPs in spherical form. The catalytic activities are specifically enhanced under the light irradiation for all Ag catalysts. In particular, under light irradiation, the blue Ag nanorod shows a maximum enhancement of more than twice that observed in the dark. It should be noted that the order of increasing catalytic performance is in close agreement with the order of absorption intensity owing to the Ag localized surface plasmon resonance (LSPR) at irradiation light wavelength. Upon consideration of infrared thermal effect, wavelength dependence on catalytic activity, and effect of radical scavengers, it can be concluded that the dehydrogenation of AB is promoted by change of charge density of the Ag NP surface derived from LSPR. The LSPR-enhanced catalytic activity can be further realized in the tandem reaction consisting of dehydrogenation of AB and hydrogenation of 4-nitrophenol, in which a similar tendency in the enhancement of catalytic activity is observed. PMID:26178067

  1. Tandem Copper-Catalyzed Propargylation/Alkyne Azacyclization/Isomerization Reaction under Microwave Irradiation: Synthesis of Fully Substituted Pyrroles.

    PubMed

    Zhang, Xiao-Yan; Yang, Zhi-Wei; Chen, Zhongzhu; Wang, Jun; Yang, Dong-Lin; Shen, Ze; Hu, Li-Li; Xie, Jian-Wu; Zhang, Jin; Cui, Hai-Lei

    2016-03-01

    A copper-catalyzed and microwave-assisted synthesis of fully substituted pyrroles has been developed. A series of pentasubstituted pyrroles, especially α-arylpyrroles, could be obtained in moderate to good yields (up to 93%) through a tandem propargylation/alkyne azacyclization/isomerization sequence from readily available β-enamino compounds and propargyl acetates. PMID:26872395

  2. Monitoring PAI-1 and VEGF Levels in 6 Human Squamous Cell Carcinoma Xenografts During Fractionated Irradiation

    SciTech Connect

    Bayer, Christine; Kielow, Achim; Schilling, Daniela; Maftei, Constantin-Alin; Zips, Daniel; Yaromina, Ala; Baumann, Michael; Molls, Michael; Multhoff, Gabriele

    2012-11-01

    Purpose: Previous studies have shown that the plasminogen activator inhibitor type-1 (PAI-1) and vascular endothelial growth factor (VEGF) are regulated by hypoxia and irradiation and are involved in neoangiogenesis. The aim of this study was to determine in vivo whether changes in PAI-1 and VEGF during fractionated irradiation could predict for radiation resistance. Methods and Materials: Six xenografted tumor lines from human squamous cell carcinomas (HSCC) of the head and neck were irradiated with 0, 3, 5, 10, and 15 daily fractions of 2 Gy. The PAI-1 and VEGF antigen levels in tumor lysates were determined by enzyme-linked immunosorbent assay kits. The amounts of PAI-1 and VEGF were compared with the dose to cure 50% of tumors (TCD{sub 50}). Colocalization of PAI-1, pimonidazole (hypoxia), CD31 (endothelium), and Hoechst 33342 (perfusion) was examined by immunofluorescence. Results: Human PAI-1 and VEGF (hVEGF) expression levels were induced by fractionated irradiation in UT-SCC-15, UT-SCC-14, and UT-SCC-5 tumors, and mouse VEGF (msVEGF) was induced only in UT-SCC-5 tumors. High hVEGF levels were significantly associated with radiation sensitivity after 5 fractions (P=.021), and high msVEGF levels were significantly associated with radiation resistance after 10 fractions (P=.007). PAI-1 staining was observed in the extracellular matrix, the cytoplasm of fibroblast-like stroma cells, and individual tumor cells at all doses of irradiation. Colocalization studies showed PAI-1 staining close to microvessels. Conclusions: These results indicate that the concentration of tumor-specific and host-specific VEGF during fractionated irradiation could provide considerably divergent information for the outcome of radiation therapy.

  3. Microwave-assisted methanolysis of green coffee oil.

    PubMed

    Oigman, S S; de Souza, R O M A; Dos Santos Júnior, H M; Hovell, A M C; Hamerski, L; Rezende, C M

    2012-09-15

    Optimisation of a microwave-assisted methanolysis was performed to obtain cafestol and kahweol directly from green coffee oil (Coffea arabica). A two-factor (the methanolysis period and temperature), three-level, factorial experimental design (3(2)) was adopted. The methanolysis procedure was performed under microwave irradiation, using closed vessel and accurate fast responding internal fibre-optic temperature probe. The effects on the responses were measured by HPLC. After 3 min of microwave irradiation (hold time) at 100°C, with 500 mg of green coffee oil, a yield higher than 99% was obtained. The yield of this reaction is 26% after 2h when working under conventional heating. The methods described in the literature lead to long reaction times, poor yields and formation of side products. The microwave-assisted technique proved to be faster, avoided undesired side products and gave better conversion, when compared to conventional heating process. PMID:23107719

  4. Effects of intermittent flow and irradiance level on back reef Porites corals at elevated seawater temperatures

    USGS Publications Warehouse

    Smith, L.W.; Birkeland, C.

    2007-01-01

    Corals inhabiting shallow back reef habitats are often simultaneously exposed to elevated seawater temperatures and high irradiance levels, conditions known to cause coral bleaching. Water flow in many tropical back reef systems is tidally influenced, resulting in semi-diurnal or diurnal flow patterns. Controlled experiments were conducted to test effects of semi-diurnally intermittent water flow on photoinhibition and bleaching of the corals Porites lobata and P. cylindrica kept at elevated seawater temperatures and different irradiance levels. All coral colonies were collected from a shallow back reef pool on Ofu Island, American Samoa. In the high irradiance experiments, photoinhibition and bleaching were less for both species in the intermittent high-low flow treatment than in the constant low flow treatment. In the low irradiance experiments, there were no differences in photoinhibition or bleaching for either species between the flow treatments, despite continuously elevated seawater temperatures. These results suggest that intermittent flow associated with semi-diurnal tides, and low irradiances caused by turbidity or shading, may reduce photoinhibition and bleaching of back reef corals during warming events. ?? 2006 Elsevier B.V. All rights reserved.

  5. Identification of low level gamma-irradiation of meats by high sensitivity comet assay

    NASA Astrophysics Data System (ADS)

    Miyahara, Makoto; Saito, Akiko; Ito, Hitoshi; Toyoda, Masatake

    2002-03-01

    The detection of low levels of irradiation in meats (pork, beef, and chicken) using the new comet assay was investigated in order to assess the capability of the procedure. The new assay includes a process that improves its sensitivity to irradiation and a novel evaluation system for each slide (influence score and comet-type distribution). Samples used were purchased at retailers and were irradiated at 0.5 and 2kGy at 0°C. The samples were processed to obtain comets. Slides were evaluated by typing comets, calculating the influence score and analyzing the comet-type distribution chart of shown on the slide. Influence scores of beef, pork, and chicken at 0kGy were 287(SD=8.0), 305 (SD=12.9), and 320 (SD=21.0), respectively. Those at 500Gy, were 305 (SD=5.3), 347 (SD=10.6), and 364 (12.6), respectively. Irradiation levels in food were successfully determined. Sensitivity to irradiation differed among samples (chicken>pork>beef).

  6. Low-level He-Ne laser in intravascular irradiation treatment of schizophrenia

    NASA Astrophysics Data System (ADS)

    Zhou, Yu-Xue; Fu, Zheng-Hua

    1998-11-01

    Intravascular low level He-Ne laser irradiation is a new therapy developed in recent years. In our hospital it was applied in the treatment and observation of 220 cases of schizophrenia, among which certain effect was achieved and about which the detail was collated and elaborated.

  7. Research of epidermal cellular vegetal cycle of intravascular low level laser irradiation in treatment of psoriasis

    NASA Astrophysics Data System (ADS)

    Zhu, Jing; Bao, Xiaoqing; Zhang, Mei-Jue

    2005-07-01

    Objective: To research epidermal cellular vegetal cycle and the difference of DNA content between pre and post Intravascular Low Level Laser Irradiation treatment of psoriasis. Method: 15 patients suffered from psoriasis were treated by intravascular low level laser irradiation (output power: 4-5mw, 1 hour per day, a course of treatment is 10 days). We checked the different DNA content of epidermal cell between pre and post treatment of psoriasis and 8 natural human. Then the percentage of each phase among the whole cellular cycle was calculated and the statistical analysis was made. Results: The mean value of G1/S phase is obviously down while G2+M phase increased obviously. T test P<0.05.The related statistical analysis showed significant difference between pre and post treatments. Conclusions: The Intravascular Low Level Laser Irradiation (ILLLI) in treatment of psoriasis is effective according to the research of epidermal cellular vegetal cycle and the difference DNA content of Intravascular Low Level Laser Irradiation between pre and post treatment of psoriasis

  8. Differential effects of UV irradiation on nuclear retinoid receptor levels in cultured keratinocytes and melanocytes.

    PubMed

    Andersson, Eva; Rosdahl, Inger; Törmä, Hans; Vahlquist, Anders

    2003-10-01

    A major risk factor for skin cancer is UV irradiation, which not only damages DNA and other photosensitive compounds like vitamin A, but may also perturb cellular signaling, e.g. via the retinoid receptor system believed to be important for cancer protection. We used cultured normal human keratinocytes and melanocytes to examine the effects of UV irradiation on the expression of the predominant retinoid receptors in the human skin (RARalpha, RARgamma and RXRalpha) and the AP-1 protein c-Jun; mRNA levels were studied by real-time PCR and protein levels by Western blot. In keratinocytes, a single dose of UVB (50 mJ/cm2) caused a rapid drop in the expression of all three receptors (mRNA levels minus 35-50% after 4 h; protein levels minus 20-45% after 8 h), which was followed over the next 40 h by a variable response, leading to full normalization for RARalpha only. In contrast, the levels of c-Jun did not change significantly after UV exposure. In melanocytes, UVB caused a similar drop of the retinoid receptor levels as in keratinocytes but this was soon followed by an increased expression leading to a complete normalization of all receptor levels within 1-3 days. The c-Jun levels in melanocytes increased 1 day after UV exposure and remained high (plus 50%) thereafter. In both cell types, a approximately 3-fold increase in apoptosis (measured by DNA fragmentation) was observed 8-48 h after UVB irradiation. In conclusion, a depletion of vitamin A and retinoid receptors by UV irradiation, together with unchanged or even increased c-Jun levels, might seriously interfere with retinoid signaling and thus promote future tumor development, especially in keratinocytes. PMID:14705796

  9. Effects of Altered Levels of Extracellular Superoxide Dismutase and Irradiation on Hippocampal Neurogenesis in Female Mice

    SciTech Connect

    Zou, Yani; Leu, David; Chui, Jennifer; Fike, John R.; Huang, Ting-Ting

    2013-11-15

    Purpose: Altered levels of extracellular superoxide dismutase (EC-SOD) and cranial irradiation have been shown to affect hippocampal neurogenesis. However, previous studies were only conducted in male mice, and it was not clear if there was a difference between males and females. Therefore, female mice were studied and the results compared with those generated in male mice from an earlier study. Methods and Materials: Female wild-type, EC-SOD-null (KO), and EC-SOD bigenic mice with neuronal-specific expression of EC-SOD (OE) were subjected to a single dose of 5-Gy gamma rays to the head at 8 weeks of age. Progenitor cell proliferation, differentiation, and long-term survival of newborn neurons were determined. Results: Similar to results from male mice, EC-SOD deficiency and irradiation both resulted in significant reductions in mature newborn neurons in female mice. EC-SOD deficiency reduced long-term survival of newborn neurons whereas irradiation reduced progenitor cell proliferation. Overexpression of EC-SOD corrected the negative impacts from EC-SOD deficiency and irradiation and normalized the production of newborn neurons in OE mice. Expression of neurotrophic factors brain-derived neurotrophic factor and neurotrophin-3 were significantly reduced by irradiation in wild-type mice, but the levels were not changed in KO and OE mice even though both cohorts started out with a lower baseline level. Conclusion: In terms of hippocampal neurogenesis, EC-SOD deficiency and irradiation have the same overall effects in males and females at the age the studies were conducted.

  10. An Evaluation of Fracture Toughness of Vinyl Ester Composites Cured under Microwave Conditions

    NASA Astrophysics Data System (ADS)

    Ku, H.; Chan, W. L.; Trada, M.; Baddeley, D.

    2007-12-01

    under ambient conditions. Higher power microwaves, 540 and 720 W with shorter duration of exposure are used to cure the composites. Short-bar method of fracture toughness measurement was used to perform the tests. Plastic (PVC) re-usable molds were designed and manufactured for producing the test samples. The results show that the fracture toughness of specimens cured by microwave conditions are generally higher than those cured under ambient conditions, provided the power level and duration of microwave irradiation are properly and optimally selected.

  11. Prostate specific antigen levels after definitive irradiation for carcinoma of the prostate

    SciTech Connect

    Schellhammer, P.F.; Schlossberg, S.M.; el-Mahdi, A.M.; Wright, G.L.; Brassil, D.N. )

    1991-05-01

    Prostate specific antigen (PSA) levels were determined in 78 patients judged clinically to be free of disease at intervals of 36 or more months (range 38 to 186 months, median 87 months) after completion of irradiation therapy by 125-iodine implantation or external beam radiation. Of this select group of patients 38% had undetectable serum PSA levels (0.5 ng./ml. or less) and 38% had PSA levels that were within normal limits (4.0 ng./ml. or less). All stages and grades were represented. Undetectable PSA levels were only rarely found (3%) in patients with carcinoma of the prostate before treatment. In 24 of these 78 patients a negative biopsy of the irradiated prostate had been obtained 18 to 42 months after treatment. When the PSA level was drawn, which ranged from 7 to 16 years after treatment, an equal percentage of these biopsied patients had either an undetectable, normal or elevated level. Irradiation is able to decrease PSA to undetectable levels in some patients with prostatic carcinoma. Whether this reflects suppression of marker production alone or, more importantly, ablation of prostate cancer producing that marker remains to be determined.

  12. Direct preparation of Cu2ZnSnSe4 films by microwave irradiation and its dependence on the Sn/(Sn + Zn) ratio

    NASA Astrophysics Data System (ADS)

    Kaigawa, Ryuji; Hashimoto, Shintaro; Irago, Tomoki; Klenk, Reiner

    2015-08-01

    Cu2ZnSnSe4 (CZTSe) films with various Sn/(Sn + Zn) ratios were directly prepared on metallic Ti foils by microwave irradiation and their properties were investigated. The Sn/(Sn + Zn) ratio and Cu/(Sn + Zn) ratio of the precursor could be preserved by using a sealed container filled with 0.15 atm of Ar. Single-phase CZTSe crystals with a kesterite (stannite) structure and without by-products were observed with Sn/(Sn + Zn) ratios between 0.4 and 0.6. The hole densities of the Cu-Zn-Sn-Se films are minimal (<1017/cm3) with Sn/(Sn + Zn) ratios ranging from 0.5 to 0.6.

  13. Generation of xylooligosaccharides from microwave irradiated agroresidues using recombinant thermo-alkali-stable endoxylanase of the polyextremophilic bacterium Bacillus halodurans expressed in Pichia pastoris.

    PubMed

    Kumar, Vikash; Satyanarayana, T

    2015-03-01

    The recombinant Pichia pastoris harboring the endoxylanase gene (TSEV1xyl) of Bacillus halodurans TSEV1 yielded a high titer of extracellular xylanase (502±23 U ml(-1)) on induction with methanol. The purified recombinant xylanase (TSEV1xyl) displayed optimal activity at 80°C and pH 9.0. The glycosylated recombinant xylanase exhibited higher thermostability (T1/2 of 45 min at 80°C) than the native enzyme (T1/2 of 35 min at 80°C). The agroresidues subjected to pretreatment (soaking in alkali followed by microwave irradiation) liberated xylooligosaccharides (XOS) upon hydrolysis with the recombinant xylanase. The removal of unhydrolyzed agroresidues, xylanase and xylose from the hydrolysate by two-step ultrafiltration led to the purification of XOS as confirmed by TLC as well as HPLC analysis. PMID:25553569

  14. Screening of lipases for the synthesis of xylitol monoesters by chemoenzymatic esterification and the potential of microwave and ultrasound irradiations to enhance the reaction rate.

    PubMed

    Rufino, Alessandra R; Biaggio, Francisco C; Santos, Julio C; de Castro, Heizir F

    2010-07-01

    Lipases from different sources, Pseudomonas fluorescens (AK lipase), Burkholderia cepacia (PS lipase), Penicillium camembertii (lipase G) and Porcine pancreas lipase (PPL), previously immobilized on epoxy SiO(2)-PVA, were screened for the synthesis of xylitol monoesters by esterification of the protected xylitol using oleic acid as acyl donor group. Among all immobilized derivatives, the highest esterification yield was achieved by P. camembertii lipase, showing to be attractive alternative to bulk chemical routes to satisfy increasing commercial demands. Further experiments were performed to determine the influence of fatty acids chain size on the reaction yield and the feasibility of using non-conventional heating systems (microwave and ultrasound irradiations) to enhance the reaction rate. PMID:20420851

  15. Long-lived frequency shifts observed in a magnetic resonance force microscope experiment following microwave irradiation of a nitroxide spin probe

    SciTech Connect

    Chen, Lei; Longenecker, Jonilyn G.; Moore, Eric W.; Marohn, John A.

    2013-04-01

    We introduce a spin-modulation protocol for force-gradient detection of magnetic resonance that enables the real-time readout of longitudinal magnetization in an electron spin resonance experiment involving fast-relaxing spins. We applied this method to observe a prompt change in longitudinal magnetization following the microwave irradiation of a nitroxide-doped perdeuterated polystyrene film having an electron spin-lattice relaxation time of T{sub 1}{approx}1ms. The protocol allowed us to discover a large, long-lived cantilever frequency shift. Based on its magnitude, lifetime, and field dependence, we tentatively attribute this persistent signal to deuteron spin magnetization created via transfer of polarization from nitroxide spins.

  16. Effect of different sulphur precursors on morphology and band-gap on the formation of Cu2ZnSnS4 (CZTS) particles with microwave irradiation

    NASA Astrophysics Data System (ADS)

    Patro, Bharati; Vijaylakshmi, S.; Sharma, Pratibha

    2016-05-01

    Cu2ZnSnS4 (CZTS) is a promising semiconductor material for ecological cost effective thin film Photovoltaic (PV) devices. As it contains earth abundant and non-toxic elements, it has the advantages over commercially available CIGS and CdTe thin film PV devices. In the present work, the pure phase Cu2ZnSnS4 particles were successfully synthesised with microwave irradiation. The morphology and phase study was carried out for the samples prepared with two different sulphur precursors viz. thiourea and thioacetamide (TAA). CZTS particles with thiourea as sulphur precursor are more crystalline than CZTS particles with TAA. The band gap of 1.654eV and 1.713eV were calculated for the samples prepared with thiourea and TAA respectively.

  17. Elevation of blood levels of zinc protoporphyrin in mice following whole-body irradiation

    SciTech Connect

    Walden, T.L. Jr.

    1983-01-01

    Elevation of zinc protoporphyrin (ZPP) levels in the blood has served as an indicator of lead poisoning and iron deficiency anemia for many years. The author has discovered that sublethal doses of whole body irradiation with X-rays also elevates ZPP two- to three-fold over normal levels. The ZPP level does not begin to increase until days 12 to 14 post-irradiation and peaks between days 18 to 20 before returning to normal levels between days 28 to 35. Increasing the radiation dose delays the onset of the rise in ZPP but does not affect the magnitude of the elevation. At lethal doses, ZPP elevation is not observed. Neither of the two previously described mechanisms which cause elevations of ZPP, namely iron deficiency and inhibition of ferrochelatase, are responsible for the radiation induced elevation of ZPP. The elevation of ZPP appears to be correlated with the recovery of the hematopoietic system from radiation injury.

  18. Testing zinc chloride as a new catalyst for direct synthesis of cellulose di- and tri-acetate in a solvent free system under microwave irradiation.

    PubMed

    El Nemr, Ahmed; Ragab, Safaa; El Sikaily, Amany

    2016-10-20

    This research demonstrates the effect of ZnCl2 as a catalyst on the esterification of commercial cotton cellulose using acetic anhydride in order to obtain di- and tri-cellulose acetates under microwave irradiation. It was discovered that microwave irradiation significantly increased the yield and reduced the reaction time. It was found that the maximum yield for cellulose triacetates was 95.83% under the reaction conditions that were as follows: 3min reaction time, 200mg of ZnCl2 catalyst and 20ml of Ac2O for 5g cellulose. However, the cellulose acetate obtained in this manner had the highest DS (2.87). The cellulose di-acetate was produced with the maximum yield of 89.97% and with the highest DS (2.69) using 25ml Ac2O, 200mg of ZnCl2 for 5g cellulose and in 3min reaction time. The effect of some factors such as the amount of used catalyst, the quantity of acetic acid anhydride and the reaction time of the esterification process have been investigated. The production of di- and tri-cellulose acetate and the degree of substitution were confirmed using Fourier-transform infrared (FTIR) and nuclear magnetic resonance (NMR). The thermal stability was investigated using thermo gravimetric analysis (TGA), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The molecular weight and the degree of polymerization were obtained using Gel Permeation Chromatography (GPC). The analysis confirmed the successful synthesis of di- and tri-cellulose acetate without degradation during the reaction; these results were found to be in contrast to some recent studies. The present study reveals that ZnCl2 is a new catalyst; it is effective as well as inexpensive and is a low toxicity catalyst for usage in cellulose esterification. PMID:27474655

  19. Polyacrylonitrile-based fiber modified with thiosemicarbazide by microwave irradiation and its adsorption behavior for Cd(II) and Pb(II).

    PubMed

    Deng, Sheng; Wang, Peng; Zhang, Guangshan; Dou, Yuan

    2016-04-15

    A novel thiosemicarbazide modified adsorbent (PAN(MW)-TSC) based on polyacrylonitrile fiber was successfully synthesized under microwave irradiation, which was applied for the uptake of Cd(II) and Pb(II) from aqueous solution subsequently. Microwave irradiation method is a new approach to achieve the modification and it turns out that just a 30min process is enough for the anchoring of functional groups in the fiber matrix. The surface characterization was performed by fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) elemental analysis (EA) and thermogravimetric analysis (TGA), indicating that the modification was successfully accomplished. Batch adsorption experiments including equilibrium isotherms, kinetics and the effects of pH and temperature on the adsorption of Cd(II) and Pb(II) were systematically studied. Among three kinetic models, the pseudo-second-order kinetic model provides the best correlation for the process. The nonlinear resolution of the Langmuir isotherm equation has been found to show the closest fit to the equilibrium date. Thermodynamic parameters, involving △G, △H and △S were also calculated from graphical interpretation of the experimental data, which suggest that metal ions adsorption onto PAN(MW)-TSC fibers is spontaneous and exothermic. Regeneration of PAN(MW)-TSC fibers loaded with metal ions was efficiently done with 0.5M HNO3, by which the investigated adsorbent could be used reproductively for five times with a small decrease in sorption capacity. The feasible preparation of PAN(MW)-TSC fibers with high adsorption capacities opens a new perspective in the potential application for wastewater treatment. PMID:26775107

  20. Low-level laser therapy on skeletal muscle inflammation: evaluation of irradiation parameters

    NASA Astrophysics Data System (ADS)

    Mantineo, Matías; Pinheiro, João P.; Morgado, António M.

    2014-09-01

    We evaluated the effect of different irradiation parameters in low-level laser therapy (LLLT) for treating inflammation induced in the gastrocnemius muscle of rats through cytokines concentration in systemic blood and analysis of muscle tissue. We used continuous (830 and 980 nm) and pulsed illuminations (830 nm). Animals were divided into five groups per wavelength (10, 20, 30, 40, and 50 mW), and a control group. LLLT was applied during 5 days with a constant irradiation time and area. TNF-α, IL-1β, IL-2, and IL-6 cytokines were quantified by ELISA. Inflammatory cells were counted using microscopy. Identical methodology was used with pulsed illumination. Average power (40 mW) and duty cycle were kept constant (80%) at five frequencies (5, 25, 50, 100, and 200 Hz). For continuous irradiation, treatment effects occurred for all doses, with a reduction of TNF-α, IL-1β, and IL-6 cytokines and inflammatory cells. Continuous irradiation at 830 nm was more effective, a result explained by the action spectrum of cytochrome c oxidase (CCO). Best results were obtained for 40 mW, with data suggesting a biphasic dose response. Pulsed wave irradiation was only effective for higher frequencies, a result that might be related to the rate constants of the CCO internal electron transfer process.

  1. Low-level Ga-Al-As laser irradiation enhances osteoblast proliferation through activation of Hedgehog signaling pathway

    NASA Astrophysics Data System (ADS)

    Li, Qiushi; Qu, Zhou; Chen, Yingxin; Liu, Shujie; Zhou, Yanmin

    2014-12-01

    Low-level laser irradiation has been reported to promote bone formation, but the molecular mechanism is still unclear. Hedgehog signaling pathway has been reported to play an important role in promoting bone formation. The aim of the present study was to examine whether low-level Ga-Al-As laser (808 nm) irradiation could have an effect on Hedgehog signaling pathway during osteoblast proliferation in vitro. Mouse osteoblastic cell line MC3T3-E1 was cultured in vitro. The cultures after laser irradiation (3.75J/cm2) were treated with recombinant N-terminals Sonic Hedgehog (N-Shh)or Hedgehog inhibitor cyclopamine (cy). The experiment was divided into 4 group, group 1:laser irradiation, group 2: laser irradiation and N-Shh, group 3: laser irradiation and cy, group 4:control with no laser irradiation. On day 1,2 and 3,cell proliferation was determined by cell counting, Cell Counting Kit-8.On 12 h and 24 h, cell cycle was detected by flow cytometry. Proliferation activity of laser irradiation and N-Shh group was remarkably increased compared with those of laser irradiation group. Proliferation activity of laser irradiation and cy group was remarkably decreased compared with those of laser irradiation group, however proliferation activity of laser irradiation and cy group was remarkably increased compared with those of control group. These results suggest that low-level Ga-Al-As laser irradiation activate Hedgehog signaling pathway during osteoblast proliferation in vitro. Hedgehog signaling pathway is one of the signaling pathways by which low-level Ga-Al-As laser irradiation regulates osteoblast proliferation.

  2. Calorimetry study of microwave absorption of some solid materials.

    PubMed

    He, Chun Lin; Ma, Shao Jian; Su, Xiu Juan; Chen, Yan Qing; Liang, Yu Shi

    2013-01-01

    In practice, the dielectric constant of a material varies the applied frequency the material composition, particle size, purity, temperature, physical state (solid or liquid), and moisture content. All of these parameters might change during processing, therefore, it is difficult to predict how well a material will absorb microwave energy in a given process. When the temperature is measured by a digital thermometer, it could not accurately reflect the true temperature of the bulk materials, especially for mixed materials. Thus, in this paper we measured the microwave absorption characteristics of different materials by calorimetry. The microwave power levels, irradiation times, and masses of the materials were varied. It was difficult to predict the microwave energy absorption characteristics of reagent-grade inorganic compounds based on their color, metallic cation, or water stoichiometry. CuO, MnO2, Fe3O4, and MnSO4 x H2O (Taishan) strongly absorbed microwave energy. Most of the remaining inorganic compounds were poor absorbers, with silica hardly absorbing any microwave energy. Carbon-based materials had significantly different microwave absorption characteristics. Activated carbon and coke were especially sensitive to microwaves, but different types of coal were poor absorbers. The jamesonite concentrate absorbed microwave energy strongly, while the zinc concentrate was a poor absorber. PMID:24779227

  3. Microwave studies of collision-induced transitions between rotational levels. VIII. Collisions between NH/sub 3/ and polar molecules

    SciTech Connect

    Fabris, A.R.; Oka, T.

    1983-03-15

    The technique of four-level microwave double resonance has been applied to the study of rotation-inversion transitions of NH/sub 3/ induced by collisions with various polar molecules. H/sub 2/O, D/sub 2/O, CH/sub 3/OH, CH/sub 3/X and CHX/sub 3/ (X = F, Cl, Br, I), NO, CO, and OCS were used as collision partners. The values of eta = ..delta..I/I observed for many four-level systems which are connected by dipole-type transitions (..delta..J = +- 1, ..delta..K = 0, parity +bold-arrow-left-right-) are given and qualitatively explained taking into account the long-range dipole--dipole interaction and the pattern of rotational energy levels of the collision partners.

  4. High-resolution tri-level process by downstream-microwave rf-biased etching

    NASA Astrophysics Data System (ADS)

    Rangelow, Ivo W.

    1991-03-01

    In this paper we discuss some properties of a novel dry etching system for high resolution transfer of e-beam generated pattern for a viable submicron lithography. In order to achieve pattern transfer by an e-beam lithography a tn-layer system has been used. The submicron pattern which has been generated in a 300 nm PBS-layer (imaging layer) was transfered into a 300 nm anorganic intermediate layer (Si3N4) by RIE with a CHF3-plasma. The underlayer of 1 micron polyimid was etched in a microwave downstream RF-biased etching system developed by Plasma Technology Ltd (UK). E-beam lithography generated structures of 75 nm size with very low image size bias were etched in Si3N4. After patterning in the polyimid layer structures with very high aspect ratio (10) could be achieved. It was observed that anisotropy is enhanced by crack-products that originate from the microwave downstream oxygen plasma and the CHF3+CH4 mixture in the space between the parallel-plate electrodes.

  5. Therapeutic and diagnostic set for irradiation the cell lines in low level laser therapy

    NASA Astrophysics Data System (ADS)

    Gryko, Lukasz; Zajac, Andrzej; Gilewski, Marian; Szymanska, Justyna; Goralczyk, Krzysztof

    2014-05-01

    In the paper is presented optoelectronic diagnostic set for standardization the biostimulation procedures performed on cell lines. The basic functional components of the therapeutic set are two digitally controlled illuminators. They are composed of the sets of semiconductor emitters - medium power laser diodes and high power LEDs emitting radiation in wide spectral range from 600 nm to 1000 nm. Emitters are coupled with applicator by fibre optic and optical systems that provides uniform irradiation of vessel with cell culture samples. Integrated spectrometer and optical power meter allow to control the energy and spectral parameters of electromagnetic radiation during the Low Level Light Therapy procedure. Dedicated power supplies and digital controlling system allow independent power of each emitter . It was developed active temperature stabilization system to thermal adjust spectral line of emitted radiation to more efficient association with absorption spectra of biological acceptors. Using the set to controlled irradiation and allowing to measure absorption spectrum of biological medium it is possible to carry out objective assessment the impact of the exposure parameters on the state cells subjected to Low Level Light Therapy. That procedure allows comparing the biological response of cell lines after irradiation with radiation of variable spectral and energetic parameters. Researches were carried out on vascular endothelial cell lines. Cells proliferations after irradiation of LEDs: 645 nm, 680 nm, 740 nm, 780 nm, 830 nm, 870 nm, 890 nm, 970 nm and lasers 650 nm and 830 nm were examined.

  6. Spectral shape deformation in inverse spin Hall voltage in Y{sub 3}Fe{sub 5}O{sub 12}|Pt bilayers at high microwave power levels

    SciTech Connect

    Lustikova, J. Shiomi, Y.; Handa, Y.; Saitoh, E.

    2015-02-21

    We report on the deformation of microwave absorption spectra and of the inverse spin Hall voltage signals in thin film bilayers of yttrium iron garnet (YIG) and platinum at high microwave power levels in a 9.45-GHz TE{sub 011} cavity. As the microwave power increases from 0.15 to 200 mW, the resonance field shifts to higher values, and the initially Lorentzian spectra of the microwave absorption intensity as well as the inverse spin Hall voltage signals become asymmetric. The contributions from opening of the magnetization precession cone and heating of YIG cannot well reproduce the data. Control measurements of inverse spin Hall voltages on thin-film YIG|Pt systems with a range of line widths underscore the role of spin-wave excitations in spectral deformation.

  7. Rapid synthesis of flower-like Cu2O architectures in ionic liquids by the assistance of microwave irradiation with high photochemical activity.

    PubMed

    Li, Shi-Kuo; Guo, Xuan; Wang, Yang; Huang, Fang-Zhi; Shen, Yu-Hua; Wang, Xue-Mei; Xie, An-Jian

    2011-07-01

    A novel and facile protocol for the rapid synthesis of flower-like Cu(2)O architectures is reported in the presence of ionic liquid 1-n-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM]BF(4)) with the assistance of microwave irradiation. The hierarchical structures are assembled from many thin nanosheets with tunable sizes by adjusting the amount of [BMIM]BF(4) in the reaction solution. Noticeably, the flower-like Cu(2)O architectures present a high surface area of 65.77 cm(2) g(-1) with a band gap of about 2.25 eV, and exhibit high and stable photochemical activity for the reduction of Cr(VI) to Cr(III) under visible light irradiation. A reasonable model of an absorption and diffusion-limited aggregation process is proposed for explaining the possible formation mechanism of the flower-like Cu(2)O. The approach described in this study provides a feasible and rapid method to synthesize flower-like Cu(2)O with a hierarchical structure that is ready for application in the fields of photocatalytic hazard pollutants. PMID:21625672

  8. Impact of proton irradiation on deep level states in n-GaN

    SciTech Connect

    Zhang, Z.; Arehart, A. R.; Cinkilic, E.; Ringel, S. A.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.; McSkimming, B.; Speck, J. S.

    2013-07-22

    Deep levels in 1.8 MeV proton irradiated n-type GaN were systematically characterized using deep level transient spectroscopies and deep level optical spectroscopies. The impacts of proton irradiation on the introduction and evolution of those deep states were revealed as a function of proton fluences up to 1.1 × 10{sup 13} cm{sup −2}. The proton irradiation introduced two traps with activation energies of E{sub C} - 0.13 eV and 0.16 eV, and a monotonic increase in the concentration for most of the pre-existing traps, though the increase rates were different for each trap, suggesting different physical sources and/or configurations for these states. Through lighted capacitance voltage measurements, the deep levels at E{sub C} - 1.25 eV, 2.50 eV, and 3.25 eV were identified as being the source of systematic carrier removal in proton-damaged n-GaN as a function of proton fluence.

  9. Effects of low-level chronic irradiation on radiosensitivity of mammals: modeling and experimental studies

    NASA Astrophysics Data System (ADS)

    Smirnova, O. A.; Yonezawa, M.

    Effects of low dose rate chronic irradiation on radiosensitivity of mammals mice are studied by experimental and modeling methods Own and reference experiments show that priming chronic low-level short-term and long-term exposures to radiation induce respectively elevated radiosensitivity and lowered radiosensitivity radioresistance in mice The manifestation of these radiosensitization and radioprotection effects are respectively increased and decreased mortality of preirradiated specimens after challenge acute irradiation in comparison with those for previously unexposed ones Taking into account that the reason of the animal death in the experiments was the hematopoietic syndrome the biophysical models of the critical body system hematopoiesis are used to simulate the dynamics of the major hematopoietic lines in mice exposed to challenge acute irradiation following the chronic one Juxtaposition of the modeling results obtained and the relevant experimental data shows that the radiosensitization effect of chronic low-level short-term less than 1 month preirradiation on mice is due to increased radiosensitivity of lymphopoietic granulocytopoietic and erythropoietic systems accompanied by increased or close to the normal level radiosensitivity of thrombocytopoietic system which are induced by the above-indicated exposure In turn the radioprotection effect of chronic low-level long-term more than 1 month preirradiation on mice is caused by decreased radiosensitivity radioresistance of the granulocytopoietic system which

  10. Molten salt-supported polycondensation of optically active diacid monomers with an aromatic thiazole-bearing diamine using microwave irradiation

    PubMed Central

    Mallakpour, Shadpour; Zadehnazari, Amin

    2013-01-01

    Microwave heating was used to prepare optically active thiazole-bearing poly(amide-imide)s. Polymerization reactions were carried out in the molten tetrabutylammonium bromide as a green molten salt medium and triphenyl phosphite as the homogenizer. Structural elucidation of the compounds was performed by Fourier transform infrared and NMR spectroscopic data and elemental analysis results. The polymeric samples were readily soluble in various organic solvents, forming low-colored and flexible thin films via solution casting. They showed high thermal stability with decomposition temperature being above 360 °C. They were assembled randomly in a nanoscale size. PMID:25685498

  11. In-situ observation of convection in droplet under microwave radiation by PIV

    NASA Astrophysics Data System (ADS)

    Asada, Masahiro; Kanazawa, Yushin; Asakuma, Yusuke; Honda, Itsuro; Phan, Chi; Parmar, Harisinh; Pareek, Vishnu; Evans, Geoffrey

    2014-08-01

    In this study, microwave irradiation is applied to a liquid droplet and the surface tension, the circulation flow and temperature of water droplet are measured dynamically under the irradiation. The droplet was allowed to return to its original temperature after the irradiation, it was found that water surface tension remained well below its original value for an extended period of time. Surface tension reduction shown similar effect of "impurity" at molecular level during the microwave, and some "memory" after microwave, which might be caused by nano-bubble. On the other hand, microwave can introduce the circulation flow of higher rotation speed and will be expected to be applied for non-contact stirring method.

  12. Alternatives to dose, quality factor and dose equivalent for low level irradiation

    SciTech Connect

    Sondhaus, C.A.; Bond, V.P.; Feinendegen, L.E.

    1988-01-01

    Randomly occurring energy deposition events produced by low levels of ionizing radiation interacting with tissue deliver variable amounts of energy to the sensitive target volumes within a small fraction of the cell population. A model is described in which an experimentally derived function relating event size to cell response probability operates mathematically on the microdosimetric event size distribution characterizing a given irradiation and thus determines the total fractional number of responding cells; this fraction measures the effectiveness of the given radiation. Normalizing to equal numbers of events produced by different radiations and applying this cell response or hit size effectiveness function (HSEF) should define radiation quality, or relative effectiveness, on a more nearly absolute basis than do the absorbed dose and dose evaluation, which are confounded when applied to low level irradiations. Examples using both calculation and experimental data are presented. 15 refs., 18 figs.

  13. Is there a stimulation of blood microcirculation at low level laser irradiation

    NASA Astrophysics Data System (ADS)

    Rogatkin, Dmitry; Dunaev, Andrey

    2014-05-01

    In 1980-2000 besides the laser surgery an intensive evolution of Low Level Laser Therapy (LLLT) had started in medicine, especially in Russia as well as in several other East-European countries. At the same time the biophysical mechanisms of LLLT are still the subject of disputes. One of the most popular clinical effects at Low Level Laser Irradiation (LLLI) being mentioned in medical publications for justification of the LLLT healing outcome is a stimulation of blood microcirculation in irradiated area. It was declared a priori at a dawn of LLLT and is now a basis of medical interpretation of healing mechanisms of LLLT at least in Russia. But in past 20 years a lot of investigation was carried out on optical registration of microhaemodynamic parameters in vivo as well as a number of noninvasive diagnostic tools was created for that. So, today it is possible to experimentally check the blood microcirculation stimulation hypothesis. Our study was aimed on that during the past 10 years. The most precision and accurate experiments we have carried out recently using simultaneously three different noninvasive diagnostic techniques: Laser Doppler Flowmetry, Tissue Reflectance Oximetry and Infrared Thermography. All these methods didn't confirm the effect on the blood microcirculation stimulation in skin or mucosa at irradiation with the power density below 50 mW/cm2 and irradiation time up to 5-6 minutes. Above this threshold the heating on 0,8…1 °C of tissue in the field of irradiation and the corresponding synchronous increase of all parameters of microhemodynamics were observed.

  14. Investigation of microwave and radiofrequency radiation levels in Vernon Township, New Jersey, November 10-15, 1985

    SciTech Connect

    Not Available

    1986-06-01

    At the request of the New Jersey Department of Environmental Protection, the U.S. Environmental Protection Agency (EPA) investigated microwave levels in Vernon Township, New Jersey. Vernon is the site of three satellite earth stations which operate a total of over 15 uplink antennas. Each of the three earth-station facilities was surveyed with broadband equipment, and frequency-specific data were collected at twenty-five sites in the surrounding communities. EPA gathered data in satellite uplink, terrestrial microwave, and broadcast-band frequencies. The highest power density found in any publicly accessible area in Vernon was 60 microwatts/sq cm on the property of one of the earth stations. The highest peak-power density found at any of the community measurement locations was approximately 0.003 microwatts/sq cm, in a frequency band that is not used for satellite uplink transmissions. Typical power density values over all the frequency bands studied are well below 0.001 microwatts/sq cm.

  15. Improved foilless Ku-band transit-time oscillator for generating gigawatt level microwave with low guiding magnetic field

    SciTech Connect

    Ling, Junpu; He, Juntao Zhang, Jiande; Jiang, Tao; Hu, Yi

    2014-09-15

    An improved foilless Ku-band transit-time oscillator with low guiding magnetic field is proposed and investigated in this paper. With a non-uniform buncher and a coaxial TM{sub 02} mode dual-resonant reflector, this improved device can output gigawatt level Ku-band microwave with relatively compact radial dimensions. Besides the above virtue, this novel reflector also has the merits of high TEM reflectance, being more suitable for pre-modulating the electron beam and enhancing the conversion efficiency. Moreover, in order to further increase the conversion efficiency and lower the power saturation time, a depth-tunable coaxial collector and a resonant cavity located before the extractor are employed in our device. Main structure parameters of the device are optimized by particle in cell simulations. The typical simulation result is that, with a 380 kV, 8.2 kA beam guided by a magnetic field of about 0.6 T, 1.15 GW microwave pulse at 14.25 GHz is generated, yielding a conversion efficiency of about 37%.

  16. Accelerated hydrolysis method to estimate the amino acid content of wheat (Triticum durum Desf.) flour using microwave irradiation.

    PubMed

    Kabaha, Khaled; Taralp, Alpay; Cakmak, Ismail; Ozturk, Levent

    2011-04-13

    The technique of microwave-assisted acid hydrolysis was applied to wholegrain wheat (Triticum durum Desf. cv. Balcali 2000) flour in order to speed the preparation of samples for analysis. The resultant hydrolysates were chromatographed and quantified in an automated amino acid analyzer. The effect of different hydrolysis temperatures, times and sample weights was examined using flour dispersed in 6 N HCl. Within the range of values tested, the highest amino acid recoveries were generally obtained by setting the hydrolysis parameters to 150 °C, 3 h and 200 mg sample weight. These conditions struck an optimal balance between liberating amino acid residues from the wheat matrix and limiting their subsequent degradation or transformation. Compared to the traditional 24 h reflux method, the hydrolysates were prepared in dramatically less time, yet afforded comparable ninhydrin color yields. Under optimal hydrolysis conditions, the total amino acid recovery corresponded to at least 85.1% of the total protein content, indicating the efficient extraction of amino acids from the flour matrix. The findings suggest that this microwave-assisted method can be used to rapidly profile the amino acids of numerous wheat grain samples, and can be extended to the grain analysis of other cereal crops. PMID:21375298

  17. Preparation of styrene-co-4-vinylpyridine magnetic polymer beads by microwave irradiation for analysis of trace 24-epibrassinolide in plant samples using high performance liquid chromatography.

    PubMed

    Zhang, Zhuomin; Zhang, Yi; Tan, Wei; Li, Gongke; Hu, Yuling

    2010-10-15

    In the study, a kind of novel styrene-co-4-vinylpyridine (St-co-4-VP) porous magnetic polymer beads was prepared by microwave irradiation using suspension polymerization. Microwave heating preparation greatly reduced the polymerization time to 1h. Physical characteristic tests suggested that these beads were cross-linking and possessed spherical shape, good magnetic response and porous morphologies with a narrow diameter distribution of 70-180 μm. Therefore, these beads displayed the long-term stability after undergoing 100-time extractions. Then, an analytical method for the determination of trace 24-epiBR in plant samples was developed by magnetic polymer bead extraction coupled with high performance liquid chromatography-fluorescence detection. St-co-4-VP magnetic polymer beads demonstrated the higher extraction selectivity for 24-epiBR than other reference compounds. Linear range was 10.00-100.0 μg/L with a relative standard deviation (RSD) of 6.7%, and the detection limit was 6.5 μg/kg. This analytical method was successfully applied to analyze the trace 24-epiBR in cole and breaking-wall rape pollen samples with recoveries of 77.2-90.0% and 72.3-83.4%, respectively, and RSDs were less than 4.1%. The amount of 24-epiBR in real breaking-wall rape pollen samples was found to be 26.2 μg/kg finally. This work proposed a sensitive, rapid, reliable and convenient analytical method for the determination of trace brassinosteroids in complicated plant samples by the use of St-co-4-VP magnetic polymer bead extraction coupled with chromatographic method. PMID:20846659

  18. Preventive and therapeutic effects of low level laser irradiation on gentamicin vestibulotoxicity in rat utricle

    NASA Astrophysics Data System (ADS)

    Rhee, Chung-Ku; Oh, Yang Hee; Ahn, Jin-Chul; Jung, Min-Sang; Kim, Yeong-Sik; Suh, Myung-Whan

    2009-02-01

    Purpose: To investigate the effects of low level laser (LLL) irradiation for the prevention and treatment of aminoglycoside-induced vestibular ototoxicity. Materials and Methods: An organotypic culture of 2 to 4 days old rat utricular maculae hair cells was used. The cultured utricular hair cells were divided into 6 groups. Group C: the hair cells were cultured for 14 days. Group G: cultured hair cells were treated with 1 mM gentamicin (GM) for 48 hours. Group L: LLL irradiation with 670 nm diode laser 3 mW/cm2 for 60 min (10.8 J/cm2)/day for 14 days. Group LG: LLL irradiation 10.8 J/ cm2/day for 2 days followed by GM insult. Group GL: treated with GM and followed by LLL irradiation 10.8 J/ cm2/day for 12 days. LGL group: LLL irradiation 10.8 J/ cm2/day for 2 days, then GM insulted, followed by the LLLT 10.8 J/ cm2/day for 10 days. The hair cells in each group were examined and counted by confocal laser scanning electron microscope on 7th and 14th days after FM1-43 staining and observed by scanning electron microscope (SEM). Results: The number of vestibular hair cells of group G was significantly less than those in group C. Group L showed no difference compared to group C. Significantly higher numbers of cells were seen in Group LG and GL comparing to group G. The cells were more in LG than group GL. Group LGL showed the most vestibular hair cells compared to the G, LG, and GL groups. SEM showed damaged hair cells in group G while they were well preserved in groups C, L, LG, GL, and LGL. Conclusion: LLL irradiation before and after GM insult on utricular hair cells were most effective to prevent and treat GM ototoxicity. This study indicates that LLL irradiation may have clinical implications to treat various vestibular and cochlear inner ear diseases.

  19. Phototherapeutic Effect of Low-Level Laser on Thyroid Gland of Gamma-Irradiated Rats.

    PubMed

    Morcos, Nadia; Omran, Manar; Ghanem, Hala; Elahdal, Mahmoud; Kamel, Nashwa; Attia, Elbatoul

    2015-01-01

    One inescapable feature of life on the earth is exposure to ionizing radiation. The thyroid gland is one of the most sensitive organs to gamma-radiation and endocrine disrupters. Low-level laser therapy (LLLT) has been used to stimulate tissue repair, and reduce inflammation. The aim of this study was to gauge the value of using Helium-Neon laser to repair the damaged tissues of thyroid gland after gamma-irradiation. Albino rats were used in this study (144 rats), divided into control, gamma, laser, and gamma plus laser-irradiated groups, each group was divided into six subgroups according to time of treatment (total six sessions). Rats were irradiated once with gamma radiation (6 Gy), and an external dose of laser (Wavelength 632.8 nm, 12 mW, CW, Illuminated area 5.73 cm(2), 2.1 mW cm(-2) 120 s, 1.4 J, 0.252 J cm(-2)) twice weekly localized on thyroid region of the neck, for a total of six sessions. Animals were sacrificed after each session. Analysis included thyroid function, oxidative stress markers, liver function and blood picture. Results revealed improvement in thyroid function, liver function and antioxidant levels, and the blood cells count after LLLT. PMID:25975382

  20. The intravascular low level laser irradiation (ILLLI) in treatment of psoriasis clinically

    NASA Astrophysics Data System (ADS)

    Zhu, Jing; Nie, Fan; Shi, Hong-Min

    2005-07-01

    Objective: The title is research curative effect of intravascular low level laser irradiation (ILLLI) in treatment of psoriasis. Method: 478 patients with psoriasis from five groups to observe their efficacy. Group1 were treated by He-Ne laser combined with drug. Group 2 were treated by semi-conductor laser combined with drug. Group 3 were treated only by He-He laser. Group 4 were treated by semi-conductor laser. Group 5 were treated only by drug. The Ridit statistical analysis was applied to all of these data. The treatment of intravascular low level laser irradiation is as follow: laser power:4-5mw, 1 hour per day and 10 days as a period combined with vit C 2.0 g iv and inhalation of O2. Results: The clinical results: the near efficient rate was 100%, in group1-4, if combined with drugs it would be better. Ridit statistical analysis showed no significant difference between group1-4, p>0.05. The efficient rate 72.97% in group5.There were showed very significant difference with group1-4, p<0.01. 2.There were no significant differences between He-Ne laser (632.8nm) and semiconductor laser(650nm); 3.The efficacy of ILLLI in psoriasis was positive correlation to the ILLLI times. Conclusions: It can improve curative effect of intravascular low levellaser irradiation (ILLLI) in treatment of psoriasis.

  1. Trade-off between the Mechanical Strength and Microwave Electrical Properties of Functionalized and Irradiated Carbon Nanotube Sheets.

    PubMed

    Williams, Tiffany S; Orloff, Nathan D; Baker, James S; Miller, Sandi G; Natarajan, Bharath; Obrzut, Jan; McCorkle, Linda S; Lebron-Colón, Marisabel; Gaier, James; Meador, Michael A; Liddle, J Alexander

    2016-04-13

    Carbon nanotube (CNT) sheets represent a novel implementation of CNTs that enable the tailoring of electrical and mechanical properties for applications in the automotive and aerospace industries. Small molecule functionalization and postprocessing techniques, such as irradiation with high-energy particles, are methods that can enhance the mechanical properties of CNTs. However, the effect that these modifications have on the electrical conduction mechanisms has not been extensively explored. By characterizing the mechanical and electrical properties of multiwalled carbon nanotube (MWCNT) sheets with different functional groups and irradiation doses, we can expand our insights into the extent of the trade-off that exists between mechanical strength and electrical conductivity for commercially available CNT sheets. Such insights allow for the optimization of design pathways for engineering applications that require a balance of material property enhancements. PMID:27044063

  2. Methodology for assessment of low level laser therapy (LLLT) irradiation parameters in muscle inflammation treatment

    NASA Astrophysics Data System (ADS)

    Mantineo, M.; Pinheiro, J. P.; Morgado, A. M.

    2013-11-01

    Several studies in human and animals show the clinical effectiveness of low level laser therapy (LLLT) in reducing some types of pain, treating inflammation and wound healing. However, more scientific evidence is required to prove the effectiveness of LLLT since many aspects of the cellular and molecular mechanisms triggered by irradiation of injured tissue with laser remain unknown. Here, we present a methodology that can be used to evaluate the effect of different LLLT irradiation parameters on the treatment of muscle inflammation on animals, through the quantification of four cytokines (TNF-α, IL-1β, IL-2 and IL-6) in systemic blood and histological analysis of muscle tissue. We have used this methodology to assess the effect of LLLT parameters (wavelength, dose, power and type of illumination) in the treatment of inflammation induced in the gastrocnemius muscle of Wistar rats. Results obtained for laser dose evaluation with continuous illumination are presented.

  3. Low level laser therapy on injured rat muscle: assessment of irradiation parameters

    NASA Astrophysics Data System (ADS)

    Mantineo, M.; Pinheiro, J. P.; Morgado, A. M.

    2013-11-01

    Although studies show the clinical effectiveness of low level laser therapy (LLLT) in facilitating the muscle healing process, scientific evidence is still required to prove the effectiveness of LLLT and to clarify the cellular and molecular mechanisms triggered by irradiation. Here we evaluate the effect of different LLLT wavelengths, using continuous coherent Laser illumination (830 nm and 980 nm) and non-coherent LED illumination (850 nm), in the treatment of inflammation induced in the gastrocnemius muscle of Wistar rats, through the quantification of cytokines in systemic blood. We verified that all applied doses of coherent radiation produce an effect on reducing the concentration of pro-inflammatory TNF-α and IL-1β cytokines, while no treatment effect was observed after irradiation with non-coherent radiation. The best results were obtained for 40 mW at 830 nm. The results may suggest an important role of coherence properties of laser in LLLT.

  4. Efficient Access to 2,3-Diarylimidazo[1,2-a]pyridines via a One-Pot, Ligand-Free, Palladium-Catalyzed Three-Component Reaction under Microwave Irradiation

    PubMed Central

    2015-01-01

    An expeditious one-pot, ligand-free, Pd(OAc)2-catalyzed, three-component reaction for the synthesis of 2,3-diarylimidazo[1,2-a]pyridines was developed under microwave irradiation. With the high availability of commercial reagents and great efficiency in expanding molecule diversity, this methodology is superior to the existing procedures for the synthesis of 2,3-diarylimidazo[1,2-a]pyridines analogues. PMID:24854606

  5. The elevation of blood levels of zinc protoporphyrin in mice following whole body irradiation

    SciTech Connect

    Walden, T.L.; Draganac, P.S.; Farkas, W.R.

    1984-05-01

    Elevation of zinc protoporphyrin (ZPP) levels in the blood has served as an indicator of lead poisoning and iron deficiency anemia for many years. We have discovered that sublethal doses of whole body irradiation with x-rays also elevates ZPP 2-3-fold over normal levels. The ZPP level does not begin to increase until days 12-14 postirradiation and peaks between days 18 and 20 before returning to normal levels between days 28 and 35. Increasing the radiation dose delays the onset of the rise in ZPP, but does not affect the magnitude of the elevation. At lethal doses, ZPP elevation is not observed. Neither of the two previously described mechanisms that cause elevations of ZPP, namely iron deficiency and inhibition of ferrochelatase, are responsible for the radiation-induced elevation of ZPP. The elevation of ZPP appears to be correlated with the recovery of the hematopoietic system from radiation injury.

  6. Immunoglobulin levels in dogs after total-body irradiation and bone marrow transplantation

    SciTech Connect

    Vriesendorp, H.M.; Halliwell, R.E.; Johnson, P.M.; Fey, T.A.; McDonough, C.M.

    1985-06-01

    The influence of total-body irradiation (TBI) and autologous or allogeneic bone marrow transplantation on serum immunoglobulin subclasses was determined in a dog model. Only IgG1 levels decreased after low-dose (+/- 4.5 Gy) TBI, but levels of all immunoglobulin classes fell after high-dose TBI (8.5 GyX1 or 2X6.0 Gy). After autologous bone marrow transplantation IgM levels were the first and IgE levels were the last to return to normal. After successful allogeneic bone marrow transplantation prolonged low IgM and IgE levels were found but IgA levels increased rapidly to over 150% of pretreatment values. A comparison of dogs with or without clinical signs or graft-versus-host disease (GVHD), revealed no differences in IgM levels. Dogs with GVHD had higher IgA but lower IgE levels. Dogs that rejected their allogeneic bone marrow cells showed significant early rises in IgE and IgA levels in comparison with dogs with GVHD. These results differ from the observations made on Ig levels in human bone marrow transplant patients. No significant differences in phytohemagglutinin stimulation tests were found between dogs with or without GVHD or dogs receiving an autologous transplant for the first four months after TBI and transplantation. An early primary or secondary involvement of humoral immunity in GVHD and graft rejection in dogs is postulated.

  7. Melting Temperatures of 2D Electron Solids in the Lowest Landau Level from Microwave Spectroscopy

    NASA Astrophysics Data System (ADS)

    Chen, Y. P.; Ganapathy, S.; Lewis, R. M.; Engel, L. W.; Tsui, D. C.; Wang, Z. H.; Ye, P. D.; Pfeiffer, L. N.; West, K. W.

    2005-03-01

    We studied the temperature(T) dependence of the microwave conductivity spectra of two dimensional electron systems in the high magnetic field (B) insulating phase (HBIP) for Landau filling factor ν<˜1/5. Such an insulating phase, believed to be a pinned electron solid, supports a characteristic pinning resonance in the conductivity spectrum. Two samples were studied. Sample 1 is a heterojunction with density n˜7x10^10 cm^ -2 and mobility μ˜5x10^6cm^2/Vs and has a single resonance in the HBIP. Sample 2 is a 65nm-wide QW with n˜6x10 ^10cm-2 and μ˜10x10^6cm^2/V and was recently found to have two resonances in the HBIP, interpreted as corresponding to two different solid phases, with one crossing over to the other as ν is reduced [1]. We studied the higher-T behavior of the resonances at many different combinations of n (through backgating) and B, and measured the characteristic temperatures Tc at which the resonances disappear. We foundTc is a non-increasing function of ν for either sample, although the function differs significantly for both samples. We interpret Tc as the melting temperature of the electron solid(s) to a quantum liquid, for which ν captures the importance of inter-electron quantum correlation. [1] Y.P. Chen et al., Phys.Rev.Lett. 93, 206805 (2004)

  8. Optimization of microwave-assisted extraction of polysaccharide from Psidium guajava L. fruits.

    PubMed

    Amutha Gnana Arasi, Michael Antony Samy; Gopal Rao, Manchineela; Bagyalakshmi, Janardanan

    2016-10-01

    This study deals with the optimization of microwave assisted extraction of polysaccharide from Psidium guajava L. fruit using Response surface methodology. To evaluate the effect of three independent variables, Water to plant material ratio, microwave power used for extraction and Irradiation time, central composite design has been employed. The yield is considered as dependent variable. The design model estimated the optimum yield of 6.81677% at 200W microwave power level, 3:1 water to plant material ratio and 20min of irradiation time. Three factors three levels Central composite design coupled with RSM was used to model the extraction process. ANOVA was performed to find the significance of the model. The polysaccharide extracted using microwave assisted extraction process was analyzed using FTIR Spectroscopy. PMID:27180292

  9. High yield production of sugars from deproteinated palm kernel cake under microwave irradiation via dilute sulfuric acid hydrolysis.

    PubMed

    Fan, Suet-Pin; Jiang, Li-Qun; Chia, Chin-Hua; Fang, Zhen; Zakaria, Sarani; Chee, Kah-Leong

    2014-02-01

    Recent years, great interest has been devoted to the conversion of biomass-derived carbohydrate into sugars, such as glucose, mannose and fructose. These are important versatile intermediate products that are easily processed into high value-added biofuels. In this work, microwave-assisted dilute sulfuric acid hydrolysis of deproteinated palm kernel cake (DPKC) was systematically studied using Response Surface Methodology. The highest mannose yield (92.11%) was achieved at the optimized condition of 148°C, 0.75N H2SO4, 10min 31s and substrate to solvent (SS) ratio (w/v) of 1:49.69. Besides that, total fermentable sugars yield (77.11%), was obtained at 170°C, 0.181N H2SO4, 6min 6s and SS ratio (w/v) of 1:40. Ridge analysis was employed to further verify the optimum conditions. Thus, this work provides fundamental data of the practical use of DPKC as low cost, high yield and environmental-friendly material for the production of mannose and other sugars. PMID:24342947

  10. Three-Dimensional Expanded Graphene-Metal Oxide Film via Solid-State Microwave Irradiation for Aqueous Asymmetric Supercapacitors.

    PubMed

    Yang, MinHo; Lee, Kyoung G; Lee, Seok Jae; Lee, Sang Bok; Han, Young-Kyu; Choi, Bong Gill

    2015-10-14

    Carbon-based electrochemical double-layer capacitors and pseudocapacitors, consisting of a symmetric configuration of electrodes, can deliver much higher power densities than batteries, but they suffer from low energy densities. Herein, we report the development of high energy and power density supercapacitors using an asymmetric configuration of Fe2O3 and MnO2 nanoparticles incorporated into 3D macroporous graphene film electrodes that can be operated in a safe and low-cost aqueous electrolyte. The gap in working potential windows of Fe2O3 and MnO2 enables the stable expansion of the cell voltage up to 1.8 V, which is responsible for the high energy density (41.7 Wh kg(-1)). We employ a household microwave oven to simultaneously create conductivity, porosity, and the deposition of metal oxides on graphene films toward 3D hybrid architectures, which lead to a high power density (13.5 kW kg(-1)). Such high energy and power densities are maintained for over 5000 cycles, even during cycling at a high current density of 16.9 A g(-1). PMID:26387450

  11. Polarity-enhanced gas-sensing performance of Au-loaded ZnO nanospindles synthesized via precipitation and microwave irradiation

    NASA Astrophysics Data System (ADS)

    Li, Yan; Lv, Tan; Zhao, Fang-Xian; Lian, Xiao-Xue; Zou, Yun-Ling; Wang, Qiong

    2016-05-01

    Loading noble metal and exploring suitable morphology to achieve excellent gas-sensing performance is very crucial for the fabrication of gas sensors. We have successfully synthesized Au-loaded ZnO (Au/ZnO) nanospindles (NSs) through a really facile procedure involving a precipitation and subsequent microwave irradiation. The as-prepared products have been characterized by X-ray diffraction (XRD), scanning electron microscope (SEM). The formation and gas-sensing mechanism of Au/ZnO NSs were discussed. The SEM micrographs revealed an interesting morphological evolution of the Au/ZnO NSs with Au-loading content ranging from 0 at. % to 7 at. %. The nanostructures were employed for gas-sensing measurement toward various gases. It indicated that the Au/ZnO NSs based sensor showed a highly enhanced response (226.81) to 400 ppm acetone gas at a relatively low working temperature (270°C), and exhibited a fast response (1 s) and recovery speed (10 s). The highly enhanced acetone gas sensitivity of Au/ZnO NSs based sensor could be attributed to its enhanced polarity owing to the peculiar morphology, Schottcky barriers, as well as catalytic effect of Au NPs. [Figure not available: see fulltext.

  12. Silver nanoparticles supported on CeO2-SBA-15 by microwave irradiation possess metal-support interactions and enhanced catalytic activity.

    PubMed

    Qian, Xufang; Kuwahara, Yasutaka; Mori, Kohsuke; Yamashita, Hiromi

    2014-11-24

    Metal-support interactions (MSIs) and particle size play important roles in catalytic reactions. For the first time, silver nanoparticles supported on CeO2-SBA-15 supports are reported that possess tunable particle size and MSIs, as prepared by microwave (MW) irradiation, owing to strong charge polarization of CeO2 clusters (i.e., MW absorption). Characterizations, including TEM, X-ray photoelectron spectroscopy, and extended X-ray absorption fine structure, were carried out to disclose the influence of CeO2 contents on the Ag particle size, MSI effect between Ag nanoparticles and CeO2-SBA-15 supports, and the strong MW absorption of CeO2 clusters that contribute to the MSIs during Ag deposition. The Ag particle sizes were controllably tuned from 1.9 to 3.9 nm by changing the loading amounts of CeO2 from 0.5 to 2.0 wt%. The Ag nanoparticle size was predominantly responsible for the high turnover frequency (TOF) of 0.41 min(-1) in ammonia borane dehydrogenation, whereas both particle size and MSIs contributed to the high TOF of 555 min(-1) in 4-nitrophenol reduction for Ag/0.5CeO2-SBA-15, which were twice as large as those of Ag/SBA-15 without CeO2 and Ag/CeO2-SBA-15 prepared by conventional oil-bath heating. PMID:25336086

  13. Hydrothermal Conversion of Giant Reed to Furfural and Levulinic Acid: Optimization of the Process under Microwave Irradiation and Investigation of Distinctive Agronomic Parameters.

    PubMed

    Antonetti, Claudia; Bonari, Enrico; Licursi, Domenico; Nassi O Di Nasso, Nicoletta; Raspolli Galletti, Anna Maria

    2015-01-01

    The hydrothermal conversion of giant reed (Arundo donax L.) to furfural (FA) and levulinic acid (LA) was investigated in the presence of dilute hydrochloric acid. FA and LA yields were improved by univariate optimization of the main reaction parameters: concentration of the acid catalyst, solid/liquid ratio of the reaction mixture, hydrolysis temperature, and reaction time. The catalytic performances were investigated adopting the efficient microwave (MW) irradiation, allowing significant energy and time savings. The best FA and LA yields were further confirmed using a traditionally heated autoclave reactor, giving very high results, when compared with the literature. Hydrolysis temperature and time were the main reaction variables to be carefully optimized: FA formation needed milder reaction conditions, while LA more severe ones. The effect of the crop management (e.g., harvest time) on FA/LA production was discussed, revealing that harvest time was not a discriminating parameter for the further optimization of both FA and LA production, due to the very high productivity of the giant reed throughout the year. The promising results demonstrate that giant reed represents a very interesting candidate for a very high contemporary production of FA and LA of up to about 70% and 90% of the theoretical yields, respectively. PMID:26633324

  14. Biological effects of low-level laser irradiation on umbilical cord mesenchymal stem cells

    NASA Astrophysics Data System (ADS)

    Chen, Hongli; Wang, Hong; Li, Yingxin; Liu, Weichao; Wang, Chao; Chen, Zhuying

    2016-04-01

    Low-level laser irradiation (LLLI) can enhance stem cell (SC) activity by increasing migration and proliferation. This study investigated the effects of LLLI on proliferation, enzymatic activity, and growth factor production in human umbilical cord mesenchymal SCs (hUC-MSCs) as well as the underlying mechanisms. hUC-MSCs were assigned to a control group (non-irradiation group) and three LLLI treatment groups (635 nm group, 808 nm group, and 635/808 nm group). Laser power density and energy density of 20 mW/cm2 and 12 J/cm2, respectively, were used for each experiment. The proliferation rate was higher in the 635 nm as compared to the other groups. LLLI at 808 nm did not induce cell proliferation. ROS levels in cells exposed to 635, 808, and 635/808 nm radiation were increased by 52.81%, 26.89%, and 21.15%, respectively, relative to the control group. CAT, tGPx, and SOD activity was increased. LLLI at 808 nm increased the levels of IL-1, IL-6, and NFκB but not VEGF. LLLI improved hUC-MSCs function and increased antioxidant activity. Dual-wavelength LLLI had more potent effects on hUC-MSCs than single-wavelength treatment. LLLI has potential applications in the preconditioning of hUC-MSCs in vitro prior to transplantation, which could improve the regenerative capacity of cells.

  15. Accelerated Regeneration of ATP Level after Irradiation in Human Skin Fibroblasts by Coenzyme Q10.

    PubMed

    Schniertshauer, Daniel; Müller, Sonja; Mayr, Tobias; Sonntag, Tanja; Gebhard, Daniel; Bergemann, Jörg

    2016-05-01

    Human skin is exposed to a number of harmful agents of which the ultraviolet (UV) component of solar radiation is most important. UV-induced damages include direct DNA lesions as well as oxidative damage in DNA, proteins and lipids caused by reactive oxygen species (ROS). Being the main site of ROS generation in the cell, mitochondria are particularly affected by photostress. The resulting mitochondrial dysfunction may have negative effects on many essential cellular processes. To counteract these effects, coenzyme Q10 (CoQ10 ) is used as a potent therapeutic in a number of diseases. We analyzed the mitochondrial respiration profile, the mitochondrial membrane potential and cellular ATP level in skin fibroblasts after irradiation. We observed an accelerated regeneration of cellular ATP level, a decrease in mitochondrial dysfunction as well as a preservation of the mitochondrial membrane potential after irradiation in human skin fibroblasts by treatment with CoQ10 . We conclude that the faster regeneration of the ATP level was achieved by a preservation of mitochondrial function by the addition of CoQ10 and that the protective effect of CoQ10 is primarily mediated via its antioxidative function. We suggest also that it might be further dependent on a stimulation of DNA repair enzymes by CoQ10 . PMID:26946184

  16. Integrated Advanced Microwave Sounding Unit-A (AMSU-A) METOP Stress Analysis Report (Qual Level Random Vibration) A1 Module

    NASA Technical Reports Server (NTRS)

    Mehitretter, R.

    1996-01-01

    Stress analysis of the primary structure of the Meteorological Satellites Project (METSAT) Advanced Microwave Sounding Units-A, A1 Module performed using the Meteorological Operational (METOP) Qualification Level 9.66 grms Random Vibration PSD Spectrum is presented. The random vibration structural margins of safety and natural frequency predictions are summarized.

  17. GREENER SYNTHETIC TRANSFORMATIONS USING MICROWAVES

    EPA Science Inventory

    Microwave irradiation has been used for a variety of organic transformations wherein chemical reactions are expedited because of selective adsorption of microwave (MW) energy by polar molecules, non-polar molecules being inert to the MW dielectric loss. The MW application under s...

  18. Further Developments in Microwave Ablation of Prostate Cells

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey; Ngo, Phong

    2005-01-01

    A report presents additional information about the subject matter of Microwave Treatment of Prostate Cancer and Hyperplasia (MSC-23049), NASA Tech Briefs, Vol. 29, No. 6 (June 2005), page 62. To recapitulate: the basic idea is to use microwaves to heat and thereby kill small volumes of unhealthy prostate tissue. The prostate is irradiated with microwaves from one or more antennas positioned near the prostate by means of catheters inserted in the urethra and/or colon. The microwave frequency, power, and exposure time, phasing, positions, and orientations of the antennas may be chosen to obtain the desired temperature rise in the heated region and to ensure that the location and extent of the heated region coincides with the region to be treated to within a few millimeters. Going beyond the description in the cited previous article, the report includes a diagram that illustrates typical placement of urethra and colon antenna catheters and presents results of computationally simulated prostate-heating profiles for several different combinations of antenna arrangements, frequencies, and delivered- energy levels as well as experimental results within phantom materials. The advantage of the two-antenna technology is that the heat generated at each antenna is significantly reduced from that associated with only one antenna. The microwave energy radiated from each antenna is focused at the tumor center by adjusting the phasing of the irradiated microwave signal from the antennas.

  19. Increased viability of odontoblast-like cells subjected to low-level laser irradiation

    NASA Astrophysics Data System (ADS)

    Oliveira, C. F.; Basso, F. G.; Lins, E. C.; Kurachi, C.; Hebling, J.; Bagnato, V. S.; de Souza Costa, C. A.

    2010-07-01

    Studies have shown that the increase of cell metabolism depends on the low level laser therapy (LLLT) parameters used to irradiate the cells. However, the optimal laser dose to up-regulate pulp cell activity remains unknown. Consequently, the aim of this study was to evaluate the metabolic response of odontoblast-like cells (MDPC-23) exposed to different LLLT doses. Cells at 20000 cells/cm2 were seeded in 24-well plates using plain culture medium (DMEM) and were incubated in a humidified incubator with 5% CO2 at 37°C. After 24 h, the culture medium was replaced by fresh DMEM supplemented with 5% (stress by nutritional deficit) or 10% fetal bovine serum (FBS). The cells were exposed to different laser doses from a near infrared diode laser prototype designed to provide a uniform irradiation of the wells. The experimental groups were: G1: 1.5 J/cm2 + 5% FBS; G2: 1.5 J/cm2 + 10% FBS; G3: 5 J/cm2 + 5% FBS; G4: 5 J/cm2 + 10% FBS; G5: 19 J/cm2 + 5% FBS; G6: 19 J/cm2 + 10% FBS. LLLT was performed in 3 consecutive irradiation cycles with a 24-hour interval. Non-irradiated cells cultured in DMEM supplemented with either 5 or 10% FBS served as control groups. The analysis of the metabolic response was performed by the MTT assay 3 h after the last irradiation. G1 presented an increase in SDH enzyme activity and differed significantly (Mann-Whitney test, p < 0.05) from the other groups. Analysis by scanning electron microscopy showed normal cell morphology in all groups. Under the tested conditions, LLLT stimulated the metabolic activity of MDPC-23 cultured in DMEM supplemented with 5% FBS and exposed to a laser dose of 1.5 J/cm2. These findings are relevant for further studies on the action of near infrared lasers on cells with odontoblast phenotype.

  20. Effect of low-level prenatal X-irradiation on postnatal development in the Wistar rat

    SciTech Connect

    Jensh, R.P.; Brent, R.L.

    1987-03-01

    The objective of this investigation was to determine the effect of low-dose prenatal X-irradiation on postnatal growth and neurobehavioral development, and whether alterations would manifest at dosages lower than those which produce anatomic malformations from exposure at the most sensitive period of organogenesis. Ninety-eight Wistar strain rats were exposed to 0.1, 0.2, or 0.4 Gy X-radiation of were sham irradiated on the 9th or 17th day of gestation. A conventional teratologic evaluation was completed on half of the animals (572 fetuses). The age of appearance of four physiologic markers and of acquisition of six reflexes was observed in 372 offspring. Exposure during early organogenesis at these levels had no effect on any of these parameters. Prenatal exposure to X-radiation on the 17th day of gestation at dosage levels greater than 0.1 Gy resulted in alterations in the appearance of three postnatal neurophysiologic parameters. Growth retardation throughout the postpartum period also was observed in the offspring. The induction of developmental and reflex alterations had a comparable threshold to the known threshold for anatomic malformations on the 9th day. These results indicate that all of the parameters studied had thresholds either at or above 0.2 Gy acute radiation, and that the postpartum developmental and reflex acquisition measures were not more sensitive indicators of exposure to X-radiation than growth parameters.

  1. L-band slot antenna design for gigawatt-level single-pulse microwave sources

    SciTech Connect

    Haworth, M.D.; Calico, S.E.; Hendricks, K.J.; McGrath, D.T.; Spencer, T.A.; Clark, M.C.; Coleman, P.D.; Sedillo, R.C.

    1996-12-31

    One significant problem with the evacuated Vlasov antenna used in the present-day gigawatt-level, 1.2-Ghz magnetically insulated line oscillator (MILO) experiments is rf breakdown in the antenna aperture. In order to reduce the field stress inherent in a single-aperture antenna at gigawatt power levels, an 81-slot non-resonant (traveling wave) antenna has been constructed. The intent of this design is to reduce the rf electric field in any one aperture below the vacuum breakdown threshold, and yet maintain a desirable far-field pattern having a localized and intense power density profile. Here the authors report on cold testing results from the slot antenna as well as on theoretical analysis of the antenna using a transmission line model aided by computer simulations. In addition, experimental data obtained using this antenna on MILO are presented. Finally, improvements to the slot antenna design are given.

  2. Flat tree-level inflationary potentials in the light of cosmic microwave background and large scale structure data

    NASA Astrophysics Data System (ADS)

    Ballesteros, G.; Casas, J. A.; Espinosa, J. R.; Ruiz de Austri, R.; Trotta, R.

    2008-03-01

    We use cosmic microwave background (CMB) and large scale structure (LSS) data to test a broad and physically well-motivated class of inflationary models: those with flat tree-level potentials (typical in supersymmetry). The non-trivial features of the potential arise from radiative corrections which give a simple logarithmic dependence on the inflaton field, making the models very predictive. We also consider a modified scenario with new physics beyond a certain high energy cut-off showing up as non-renormalizable operators (NRO) in the inflaton field. We find that both kinds of models fit CMB and LSS data remarkably well, with very few free parameters. Besides, many of these models naturally predict a reasonable number of e-folds. A robust feature of these scenarios is the smallness of tensor perturbations (r \\lesssim 10^{-3} ). The NRO case can give a sizable running of the spectral index while achieving a sufficient number of e-folds. We use Bayesian model comparison tools to assess the relative performance of the models. We believe that these scenarios can be considered as a standard physical class of inflationary models, on a similar footing to monomial potentials.

  3. Effects of irradiation and semistarvation on rat thyrotropin beta subunit messenger ribonucleic acid, pituitary thyrotropin content, and thyroid hormone levels

    SciTech Connect

    Litten, R.Z. ); Carr, F.E. ); Fein, H.G.; Smallridge, R.C. )

    1990-01-01

    The effect of radiation-induced anorexia on serum thyrotropin (TSH), pituitary TSH-{beta} mRNA, pituitary TSH content, serum thyroxine (T{sub 4}), and serum 3,5,3{prime}-triiodothyronine (T{sub 3}) was investigated using feed-matched controls. Rats received 10 Gy gamma whole-body irradiation and were examined 1-3 days postirradiation. Feed-matched and untreated controls were also studied. The average food intake of the irradiated and feed-matched groups was approximately 18% of the untreated controls. Over the three day period both the irradiated and feed-matched groups lost a significant amount of body weight. The serum T{sub 4} levels of both the irradiated and feed-matched groups were not significantly different from each other, but were significantly depressed when compared to the untreated control group. The serum TSH and T{sub 3} were, however, significantly greater in the irradiated than the feed-matched groups at day 3 posttreatment. To determine if the difference in the serum TSH level between the two groups was due to a pretranslational alteration in TSH production, we measured the TSH-{beta} mRNA using an RNA blot hybridization assay. We found that the TSH-{beta} mRNA level was the same in the irradiated and feed-matched groups, suggesting that the mechanism responsible for the radiation-induced increase in the serum TSH level is posttranscriptional. Pituitary TSH content in the irradiated rats was significantly less than in pair-fed controls, suggesting that irradiation may permit enhanced secretion of stored hormone.

  4. Characterization and comparison of photocatalytic activities of prepared TiO2/graphene nanocomposites using titanium butoxide and TiO2 via microwave irradiation method

    NASA Astrophysics Data System (ADS)

    Darvishi, Motahareh; Seyed-Yazdi, Jamileh

    2016-08-01

    Photocatalysis based on TiO2 nanostructures with nanoscale hybridization of graphene, is a promising method to create highly conductive composite materials and surfaces with enhanced light absorption. In this study, graphite-oxide (GO) was produced by improved Hummers’ method followed by synthesis of TiO2/graphene nanocomposites. We used two precursors, titanium butoxide (TBO) and commercial TiO2, to produce nanocomposites in a mixture of water/ethanol and graphene-oxide, for hydrolysis of titania precursors on graphene-oxide sheets resulting in the formation of nanocomposites. Microwave irradiation is used to reduce graphene-oxide into graphene. TiO2/graphene nanocomposites in both cases demonstrate enhancement of overall photocatalytic activity compared with titania precursors which was examined by degradation of methylene blue (MB). In this study, nanocomposites were synthesized with different mass ratios of GO compare to titania precursors (i.e. GO: 1, 5 and 8 wt%). Photocatalytic performance increased with the increasing content of graphene in both cases. The reduction rate of MB for TiO2 was 62% and for TiO2/graphene (TiO2/G) (GO: 8 wt%) was 85% after 90 min, and for TBO and TBO/G (GO: 8 wt%) was 3% and 99.95%, respectively. SEM, XRD, Fourier transform infrared and UV–vis spectroscopy were used to characterize the synthesized nanocomposites. FTIR analysis demonstrates the formation of Ti–O–C bonds and confirms the formation of nanocomposites made of graphene and titania nanoparticles.

  5. Mechanisms of an increased level of serum iron in gamma-irradiated mice.

    PubMed

    Xie, Li-hua; Zhang, Xiao-hong; Hu, Xiao-dan; Min, Xuan-yu; Zhou, Qi-fu; Zhang, Hai-qian

    2016-03-01

    The potential mechanisms underlying the increase in serum iron concentration in gamma-irradiated mice were studied. The gamma irradiation dose used was 4 Gy, and cobalt-60 ((60)Co) source was used for the irradiation. The dose rate was 0.25 Gy/min. In the serum of irradiated mice, the concentration of ferrous ions decreased, whereas the serum iron concentration increased. The concentration of ferrous ions in irradiated mice returned to normal at 21 day post-exposure. The concentration of reactive oxygen species in irradiated mice increased immediately following irradiation but returned to normal at 7 day post-exposure. Serum iron concentration in gamma-irradiated mice that were pretreated with reduced glutathione was significant lower (p < 0.01) than that in mice exposed to gamma radiation only. However, the serum iron concentration was still higher than that in normal mice (p < 0.01). This change was biphasic, characterized by a maximal decrease phase occurring immediately after gamma irradiation (relative to the irradiated mice) and a recovery plateau observed during the 7th and 21st day post-irradiation, but serum iron recovery was still less than that in the gamma-irradiated mice (4 Gy). In gamma-irradiated mice, ceruloplasmin activity increased and serum copper concentration decreased immediately after irradiation, and both of them were constant during the 7th and 21st day post-irradiation. It was concluded that ferrous ions in irradiated mice were oxidized to ferric ions by ionizing radiation. Free radicals induced by gamma radiation and ceruloplasmin mutually participated in this oxidation process. The ferroxidase effect of ceruloplasmin was achieved by transfer of electrons from ferrous ions to cupric ions. PMID:26511140

  6. Effect of microwave-enhanced superconductivity in YBa2Cu3O7 Bi-crystalline grain bounda ry weak-links

    NASA Technical Reports Server (NTRS)

    Fu, C. M.; Chen, C. M.; Lin, H. C.; Wu, K. H.; Juang, J. Y.; Uen, T. M.; Gou, Y. S.

    1995-01-01

    We have studied systematically the effect of microwave irradiation on the temperature dependent resistivity (R(I) and the current-voltage (I-V) characteristics of YBa2Gu3O(7 - x) (YBCO) bicrystalline grain boundary weak-links (GBWL's), with grain boundary of three different tilt angles. The superconducting transition temperature, T(sub c), has significant enhancement upon microwave irradiation. The microwave enhanced T(sub c) is increased as a function of incident microwave power, but limited to an optimum power level. The GBWL's of 45 deg tilt boundary has shown to be most sensitive to the microwave irradiation power, and the GBWL's of 36.8 deg tilt boundary has displayed a moderate response. In contrast, no enhancement of T(sub c) was observed in the GBWL's of 24 deg tilt boundary, as well as in the uniform films. Under the microwave irradiation, the R(T) dependent is hystertic as the transition taken from superconducting state to normal state and vice versa. Mechanisms associated with the redistribution of nonequilibrium quasiparticles under microwave irradiation are discussed.

  7. Effect of microwave-enhanced superconductivity in YBa{sub 2}Cu{sub 3}O{sub 7} bi-crystalline grain boundary weak-links

    SciTech Connect

    Fu, C.M.; Chen, C.M.; Lin, H.C.

    1994-12-31

    We have studied systematically the effect of microwave irradiation on the temperature dependent resistivity R(T) and the current-voltage (I-V) characteristics of YBa{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) bicrystalline grain boundary weak-links (GBWLs), with grain boundary of three different tilt angles. The superconducting transition temperature, T{sub c}, has significant enhancement upon microwave irradiation. The microwave enhanced T{sub c} is increased as a function of incidence microwave power, but limited to an optimum power level. The GBWLs of 45{degrees} tilt boundary has shown to be most sensitive to the microwave irradiation power, and the GBWLs of 36.8{degrees} tilt boundary has displayed a moderate response. In contrast, no enhancement of T{sub c} was observed in the GBWLs of 24{degrees} tilt boundary, as well as in the uniform films. Under the microwave irradiation, the R(T) dependence is hysteretic as the transition taken from superconducting state to normal state and vice versa. Mechanisms associated with the redistribution of nonequilibrium quasiparticles under microwave irradiation are discussed.

  8. Intravascular low-level laser irradiation in the treatment of psoriasis

    NASA Astrophysics Data System (ADS)

    Zhu, Jing; Shi, Hong-Min; Zhang, Hui-Guo; Zhang, Mei-Jue; Xu, Jian; Zhou, Min; Hu, Guo-Qiang

    1998-11-01

    Liu TCY et al have put forward the biological information model on low intensity laser irradiation (BIML): low intensity laser irradiation couples with intracellular messenger through the chromophore absorption in the cell membrane: hot-color laser irradiation activates cAMP phosphodiestererase through Gi protein, or activates phosphoinositide phospholipase C through G protein, or activates one of receptor-associated kinases: cAMP; cold- color laser irradiation activates adenylate cyclase through Gs protein: cAMP$ARUP. In this paper, under the guidance of BIML, we applied the intravascular low intensity He-He laser irradiation on blood to a patient of idiopathic edema, and succeeded.

  9. Optical Measurements of Strong Microwave Fields with Rydberg Atoms in a Vapor Cell

    NASA Astrophysics Data System (ADS)

    Anderson, D. A.; Miller, S. A.; Raithel, G.; Gordon, J. A.; Butler, M. L.; Holloway, C. L.

    2016-03-01

    We present a spectral analysis of Rydberg atoms in strong microwave fields using electromagnetically induced transparency (EIT) as an all-optical readout. The measured spectroscopic response enables optical, atom-based electric-field measurements of high-power microwaves. In our experiments, microwaves are irradiated into a room-temperature rubidium vapor cell. The microwaves are tuned near the two-photon 65 D -66 D Rydberg transition and reach an electric-field strength of 230 V /m , about 20% of the microwave-ionization threshold of these atoms. A Floquet treatment is used to model the Rydberg-level energies and their excitation rates. We arrive at an empirical model for the field-strength distribution inside the spectroscopic cell that yields excellent overall agreement between the measured and calculated Rydberg EIT-Floquet spectra. Using spectral features in the Floquet maps, we achieve an absolute strong-field measurement precision of 6%.

  10. Role of laser fluence in protein synthesis of cultured DRG neurons following low-level laser irradiation

    NASA Astrophysics Data System (ADS)

    Zheng, Liqin; Qiu, Caimin; Wang, Yuhua; Zeng, Yixiu; Yang, Hongqin; Zhang, Yanding; Xie, Shusen

    2014-11-01

    Low-level lasers have been used to relieve pain in clinical for many years. But the mechanism is not fully clear. In animal models, nitric oxide (NO) has been reported involving in the transmission and modulation of nociceptive signals. So the objective of this study was to establish whether low-level laser with different fluence could stimulate the production of nitric oxide synthese (NOS), which produces NO in cultured primary dorsal root ganglion neurons (DRG neurons). The primary DRG neurons were isolated from healthy Sprague Dawley rats (8-12 weeks of age) and spread on 35 mm culture dishes specially used for confocal microscopy. 24 hours after spreading, cells were irradiated with 658 nm laser for two consecutive days at the energy density of 20, 40, 60 and 80 mJ·cm-2 respectively. Control groups were not exposed to the laser, but were kept under the same conditions as the irradiated ones. The synthesis of NOS after laser irradiation was detected by immunofluorescence assay, and the changes of NOS were evaluated using confocal microscopy and Image J software. The results showed that all the laser fluence could promote the production of NOS in DRG neurons, especially the 60 mJ·cm-2 . These results demonstrated that low-level laser irradiation could modify protein synthesis in a dose- or fluence- dependent manner, and indicated that low-level laser irradiation might achieve the analgesic effect through modulation of NO production.

  11. Microwave hydrology: A trilogy

    NASA Technical Reports Server (NTRS)

    Stacey, J. M.; Johnston, E. J.; Girard, M. A.; Regusters, H. A.

    1985-01-01

    Microwave hydrology, as the term in construed in this trilogy, deals with the investigation of important hydrological features on the Earth's surface as they are remotely, and passively, sensed by orbiting microwave receivers. Microwave wavelengths penetrate clouds, foliage, ground cover, and soil, in varying degrees, and reveal the occurrence of standing liquid water on and beneath the surface. The manifestation of liquid water appearing on or near the surface is reported by a microwave receiver as a signal with a low flux level, or, equivalently, a cold temperature. Actually, the surface of the liquid water reflects the low flux level from the cosmic background into the input terminals of the receiver. This trilogy describes and shows by microwave flux images: the hydrological features that sustain Lake Baykal as an extraordinary freshwater resource; manifestations of subsurface water in Iran; and the major water features of the Congo Basin, a rain forest.

  12. Evaluation of low level laser therapy irradiation parameters on rat muscle inflammation through systemic blood cytokines

    NASA Astrophysics Data System (ADS)

    Mantineo, Matias; Pinheiro, João. P.; Morgado, António M.

    2014-02-01

    Low level laser therapy (LLLT) has been used for inflammation treatment. Here, we evaluate the effect of different doses, using continuous (830 and 980 nm) and pulsed illumination (830 nm), in the treatment of inflammation induced in the gastrocnemius muscle of Wistar rats, through cytokines concentration in systemic blood and histological analysis of muscle tissue. Animals were randomly divided into five groups per wavelength (5 animals per group: 10, 20, 30, 40 and 50 mW) plus a control group. LLLT was applied during five days, with constant exposure time and irradiated area (3 minutes; 0.5026 cm2). Blood was collected on days 0, 3 and 6. TNF-α, IL-1β, IL-2 and IL-6 cytokines were quantified by ELISA. Rats were killed on day 6. Muscle inflammatory cells were counted using optical microscopy. Treatment effects occurred for all applied doses (largest effect at 40 mW: 7.2 J, 14 J/cm2 per irradiation), with reduction of proinflammatory TNF-α, IL-1β and IL-6 cytokines and lower number of inflammatory cells. Results were better for 830 nm. Identical methodology was used with pulsed illumination. Average power (40 mW) and duty cycle were kept constant (80%) at five frequencies (5, 25, 50, 100 and 200 Hz). Treatment effects were observed at higher frequencies, with no significant differences between them. However, the treatment effect was lower than for continuous illumination. LLLT effect on inflammation treatment can be monitored by measuring systemic blood cytokines. A larger treatment effect was observed with continuous illumination, where results seem to be compatible with a biphasic dose response.

  13. Identification of irradiated pepper with the level of hydrogen gas as a probe

    SciTech Connect

    Dohmaru, T.; Furuta, M.; Katayama, T.; Toratani, H.; Takeda, A. )

    1989-12-01

    A novel method to detect whether or not a particular pepper has been irradiated has been developed which is based on the fact that H2 is formed in organic substances irradiated with ionizing radiation. Following gamma irradiation, black and white peppers were ground to powder in a gastight ceramic mill. By gas-chromatographic analysis of the gas in the mill, we observed that H2 had been released from the irradiated pepper grains. Curves plotting the H2 content vs storage time at storage temperatures of 7, 22, and 30 degrees C showed that the higher the temperatures, the smaller the H2 content, and that identification of irradiated pepper was possible for 2-4 months after 10 kGy irradiation.

  14. Chemical composition, at consuming ripeness level of tomatoes irradiated at mature green and greenish yellow stages of maturity

    NASA Astrophysics Data System (ADS)

    Al-Wandawi, H. K.; Abdul-Rahman, M. H.; Al-Shaickley, K. A.

    Tomatoes (Lycopersicon esculentum L.,var.Monte carlo) have been Y-irradiated (100-400Krad) and left to ripen to consuming ripeness. The results revealed that in fruits irradiated with 100,200 and 300 krad at mature-green, 48 hour after harvesting and at greenish yellow stages of maturity, 24 hours after harvesting, the levels of ascorbic acid were accounted to 62, 51, 27% and 84, 59, 34% of control samples respectively. In fruits irradiated with 200 krad at mature-green stage and 48 hours after harvesting and in fruits irradiated with 400 krad at greenish yellow stage and 48 hours after harvesting, the levels of lycopene were 279 and 246% of that of control samples; while the lowest levels of lycopene were in fruits irradiated with 400 krad and at mature-green and greenish yellow stages and 48 hours after harvesting where lycopene accounted to 11 and 24% respectively when compared to control samples . on the other hand, radiation had no significant effect on PH, titrable acidity and °Brix of tomatoes.

  15. Biomass allocation, morphology and photosynthesis of invasive and noninvasive exotic species grown at four irradiance levels

    NASA Astrophysics Data System (ADS)

    Feng, Yulong; Wang, Junfeng; Sang, Weiguo

    2007-01-01

    We tested the hypotheses that invasive species had higher irradiance plasticity, capture ability and efficiency than noninvasive species using two invasive aliens - Ageratina adenophora and Chromolaena odorata, and one noninvasive alien - Gynura sp. The three aliens were grown at 4.5%, 12.5%, 36%, 50% and 100% irradiances for 64 days before harvesting. The plastic response of specific leaf area (SLA) contributed to improved light interception at low irradiance, carbon gain and water balance at high irradiance. It was a good predictor for intraspecific irradiance responses of leaf area ratio (LAR), leaf area:root mass ratio, maximum photosynthetic rate ( Pmax) and net assimilation rate (NAR). Biomass allocation-related traits were species specific and their plasticity to irradiance was low. The high root mass fraction, leaf mass fraction and LAR distinguished the two invaders from Gynura. However, other resource capture-related traits, such as SLA, NAR and Pmax, were not always higher for the invaders than for Gynura. Furthermore, plasticity to irradiance was not different between the invasive and noninvasive aliens. With increasing irradiance, Gynura decreased biomass investment to roots and leaves but increased the investment to support structures adversely affecting both low and high irradiance acclimation. Ageratina might invade new habitat successfully through tolerating shading at low irradiance and outshading competitors by forming dense stands when irradiance is increased. The results suggested that both resource capture-related traits and irradiance acclimation conferred competitive advantage to the two invaders and some traits were common for invasive and noninvasive aliens but others were specific for invaders.

  16. No significant level of inheritable interchromosomal aberrations in the progeny of bystander primary human fibroblasts after alpha particle irradiation

    NASA Astrophysics Data System (ADS)

    Hu, Burong; Zhu, Jiayun; Zhou, Hongning; Hei, Tom K.

    2013-02-01

    A major concern for bystander effects is the probability that normal healthy cells adjacent to the irradiated cells become genomically unstable and undergo further carcinogenesis after therapeutic irradiation or space mission where astronauts are exposed to low dose of heavy ions. Genomic instability is a hallmark of cancer cells. In the present study, two irradiation protocols were performed in order to ensure pure populations of bystander cells and the genomic instability in their progeny were investigated. After irradiation, chromosomal aberrations of cells were analyzed at designated time points using G2 phase premature chromosome condensation (G2-PCC) coupled with Giemsa staining and with multiplex fluorescent in situ hybridization (mFISH). Our Giemsa staining assay demonstrated that elevated yields of chromatid breaks were induced in the progeny of pure bystander primary fibroblasts up to 20 days after irradiation. mFISH assay showed no significant level of inheritable interchromosomal aberrations were induced in the progeny of the bystander cell groups, while the fractions of gross aberrations (chromatid breaks or chromosomal breaks) significantly increased in some bystander cell groups. These results suggest that genomic instability occurred in the progeny of the irradiation associated bystander normal fibroblasts exclude the inheritable interchromosomal aberration.

  17. Effects of low-level gamma irradiation on the characteristics of fermented pork sausage during storage

    NASA Astrophysics Data System (ADS)

    Kim, I. S.; Jo, C.; Lee, K. H.; Lee, E. J.; Ahn, D. U.; Kang, S. N.

    2012-04-01

    The effect of gamma irradiation (0.5, 1, 2, and 4 kGy) on the quality of vacuum-packaged dry fermented sausages during refrigerated storage was evaluated. At Day 0 of irradiation, the pH, redness (CIE a*), yellowness (CIE b*), 2-thiobarbituric acid-reactive substances (TBARS) and volatile basic nitrogen (VBN) values of samples irradiated at 2 and 4 kGy were higher (p<0.05), but the CIE L* values (lightness) were lower than those of the non-irradiated control (p<0.05). At<1 kGy irradiation, however, the pH, CIE L*, CIE a* and CIE b*-value of samples were not significantly influenced by irradiation. The CIE a*, and CIE b*-values of samples irradiated at 2 and 4 kGy decreased with the increase of storage time. The VBN, TBARS, and CIE L*-values of samples irradiated at 4 kGy were not changed significantly during refrigerated storage for 90 days (p>0.05). The total plate counts (TPC) and lactic acid bacteria (LAB) in the samples irradiated at 4 kGy were significantly lower (p<0.01) than those with lower irradiation doses. At the end of storage, the TPC, coliform, and LAB in the samples were not increased after irradiation at 1, 0.5 and 1 kGy, respectively. TPC and LAB were not detected in samples irradiated at 4 kGy at Day 90. In addition, no coliform bacteria were found in samples irradiated at 1 kGy during refrigerated storage. Sensory evaluation indicated that the rancid flavor of samples irradiated at 4 kGy was significantly higher, but aroma and taste scores were lower than those of the control at Day 3 of storage. Irradiation of dry fermented sausages at 2 kGy was the best conditions to prolong the shelf-life and decrease the rancid flavor without significant quality deterioration.

  18. Proposal for efficient two-dimensional atom localization using probe absorption in a microwave-driven four-level atomic system

    SciTech Connect

    Ding Chunling; Li Jiahua; Yang Xiaoxue; Xiong Hao; Zhang Duo

    2011-10-15

    The behavior of two-dimensional (2D) atom localization is explored by monitoring the probe absorption in a microwave-driven four-level atomic medium under the action of two orthogonal standing-wave fields. Because of the position-dependent atom-field interaction, the information about the position of the atom can be obtained via the absorption measurement of the weak probe field. It is found that the localization behavior is significantly improved due to the joint quantum interference induced by the standing-wave and microwave-driven fields. Most importantly, the atom can be localized at a particular position and the maximal probability of finding the atom in one period of the standing-wave fields reaches unity by properly adjusting the system parameters. The proposed scheme may provide a promising way to achieve high-precision and high-resolution 2D atom localization.

  19. Irradiation creep in type 316 stainless steel and us PCA with fusion reactor He/dpa levels*1

    NASA Astrophysics Data System (ADS)

    Grossbeck, M. L.; Horak, J. A.

    1988-07-01

    Irradiation creep was investigated in Type 316 stainless steel (316 SS) and US Fusion Program PCA using a tailored spectrum of the Oak Ridge Research Reactor in order to achieve a He/dpa value characteristic of a fusion reactor first wall. Pressurized tubes with stresses of 20 to 470 MPa were irradiated at temperatures of 330, 400, 500, and 600°C. It was found that irradiation creep was independent of temperature in this range and varied linearly with stress at low stresses, but the stress exponent increased to 1.3 and 1.8 for 316 SS and PCA, respectively, at higher stresses. Specimens of PCA irradiated in the ORR and having helium levels up to 200 appm experienced a 3 to 10 times higher creep rate than similar specimens irradiated in the FFTF and having helium levels below 20 appm. The higher creep rates are attributed to either a lower flux or the presence of helium. A mechanism involving interstitial helium-enhanced climb is proposed.

  20. Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: AMSU-A1 METSAT Instrument (S/N 105) Qualification, Level Vibration Tests of December 1998 (S/O 605445, OC-419)

    NASA Technical Reports Server (NTRS)

    Heffner, R. J.

    1998-01-01

    This is the Engineering Test Report, AMSU-AL METSAT Instrument (S/N 105) Qualification Level Vibration Tests of December 1998 (S/0 605445, OC-419), for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

  1. Microwave Ovens

    MedlinePlus

    ... Required Reports for the Microwave Oven Manufacturers or Industry Exemption from Certain Reporting and Recordkeeping Requirements for ... Microwave Ovens (PDF) (PDF - 2.5MB) FDA eSubmitter Industry Guidance - Documents of Interest Notifications to Industry (PDF ...

  2. Effect of total lymphoid irradiation on levels of serum autoantibodies in systemic lupus erythematosus and in rheumatoid arthritis

    SciTech Connect

    Tanay, A.; Schiffman, G.; Strober, S.

    1986-01-01

    The effects of total lymphoid irradiation (TLI) on serum levels of autoantibodies, and of antibodies to diphtheria toxoid, tetanus toxoid, and pneumococcal polysaccharide in patients with lupus nephritis were compared with those previously observed in rheumatoid arthritis (RA) patients. Baseline levels of antibodies to diphtheria toxoid and tetanus toxoid decreased significantly after TLI in patients with lupus and RA, but antibody levels to pneumococcal polysaccharide remained unchanged. After TLI, the levels of antinuclear and anti-DNA antibodies were reduced significantly in lupus, but levels of rheumatoid factor, antinuclear, and antigranulocyte antibodies all tended to increase in RA.

  3. Reduction of Fermi level pinning and recombination at polycrystalline CdTe surfaces by laser irradiation

    SciTech Connect

    Simonds, Brian J.; Kheraj, Vipul; Palekis, Vasilios; Ferekides, Christos; Scarpulla, Michael A.

    2015-06-14

    Laser processing of polycrystalline CdTe is a promising approach that could potentially increase module manufacturing throughput while reducing capital expenditure costs. For these benefits to be realized, the basic effects of laser irradiation on CdTe must be ascertained. In this study, we utilize surface photovoltage spectroscopy (SPS) to investigate the changes to the electronic properties of the surface of polycrystalline CdTe solar cell stacks induced by continuous-wave laser annealing. The experimental data explained within a model consisting of two space charge regions, one at the CdTe/air interface and one at the CdTe/CdS junction, are used to interpret our SPS results. The frequency dependence and phase spectra of the SPS signal are also discussed. To support the SPS findings, low-temperature spectrally-resolved photoluminescence and time-resolved photoluminescence were also measured. The data show that a modest laser treatment of 250 W/cm{sup 2} with a dwell time of 20 s is sufficient to reduce the effects of Fermi level pinning at the surface due to surface defects.

  4. Low-level laser irradiation effect on endothelial cells under conditions of hyperglycemia.

    PubMed

    Góralczyk, Krzysztof; Szymańska, Justyna; Szot, Katarzyna; Fisz, Jacek; Rość, Danuta

    2016-07-01

    Diabetes mellitus is considered to be a very serious lifestyle disease leading to cardiovascular complications and impaired wound healing observed in the diabetic foot syndrome. Chronic hyperglycemia is the source of the endothelial activation. The inflammatory process in diabetes is associated with the secretion of inflammatory cytokines by endothelial cells, e.g., tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6). The method of phototherapy using laser beam of low power (LLLT-low-level laser therapy) effectively supports the conventional treatment of diabetic vascular complications such as diabetic foot syndrome. The aim of our study was to evaluate the effect of low-power laser irradiation at two wavelengths (635 and 830 nm) on the secretion of inflammatory factors (TNF-α and IL-6) by the endothelial cell culture-HUVEC line (human umbilical vein endothelial cell)-under conditions of hyperglycemia. It is considered that adverse effects of hyperglycemia on vascular endothelial cells may be corrected by the action of LLLT, especially with the wavelength of 830 nm. It leads to the reduction of TNF-α concentration in the supernatant and enhancement of cell proliferation. Endothelial cells play an important role in the pathogenesis of diabetes; however, a small number of studies evaluate an impact of LLLT on these cells under conditions of hyperglycemia. Further work on this subject is warranted. PMID:26861982

  5. Adhesive bonding using variable frequency microwave energy

    DOEpatents

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

    1998-09-08

    Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

  6. Adhesive bonding using variable frequency microwave energy

    DOEpatents

    Lauf, Robert J.; McMillan, April D.; Paulauskas, Felix L.; Fathi, Zakaryae; Wei, Jianghua

    1998-01-01

    Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy.

  7. Adhesive bonding using variable frequency microwave energy

    DOEpatents

    Lauf, R.J.; McMillan, A.D.; Paulauskas, F.L.; Fathi, Z.; Wei, J.

    1998-08-25

    Methods of facilitating the adhesive bonding of various components with variable frequency microwave energy are disclosed. The time required to cure a polymeric adhesive is decreased by placing components to be bonded via the adhesive in a microwave heating apparatus having a multimode cavity and irradiated with microwaves of varying frequencies. Methods of uniformly heating various articles having conductive fibers disposed therein are provided. Microwave energy may be selectively oriented to enter an edge portion of an article having conductive fibers therein. An edge portion of an article having conductive fibers therein may be selectively shielded from microwave energy. 26 figs.

  8. Experimental verification of equilibrium para-hydrogen levels in hydrogen moderators irradiated by spallation neutrons at J-PARC

    NASA Astrophysics Data System (ADS)

    Teshigawara, M.; Harada, M.; Tatsumoto, H.; Aso, T.; Ohtsu, K.; Takada, H.; Futakawa, M.; Ikeda, Y.

    2016-02-01

    By sampling gaseous hydrogen from a circulating liquid hydrogen loop for Laser Raman spectroscopy, we measured the para-/ortho-hydrogen fractions in liquid hydrogen under neutron irradiation for the first time to identify whether irradiated hydrogen has an elevated ortho-hydrogen fraction. This measurement indicates that para-hydrogen equilibrium persists at 300 kW proton power in the presence of an iron(III) oxide hydroxide [Fe(OH)3] catalyst. The measurements will be repeated as the power at the Japan Proton Accelerator Research Complex (J-PARC) increases to the MW level.

  9. Low irradiances affect abscisic acid, indole-3-acidic acid, and cytokinin levels of wheat (Triticum aestivum L.) tissues

    NASA Technical Reports Server (NTRS)

    Nan, R.; Carman, J. G.; Salisbury, F. B.

    1999-01-01

    Wheat (Triticum aestivum L.) plants were grown under four irradiance levels: 1,400, 400, 200, and 100 micromol m-2 s-1. Leaves and roots were sampled before, during, and after the boot stage, and levels of abscisic acid (ABA), indole-3-acetic acid (IAA), zeatin, zeatin riboside, dihydrozeatin, dihydrozeatin riboside, isopentenyl adenine, and isopentenyl adenosine were quantified using noncompetitive indirect ELISA systems. Levels of IAA in leaves and roots of plants exposed to 100 micromol m-2 s-1 of irradiance were 0.7 and 2.9 micromol kg-1 dry mass (DM), respectively. These levels were 0.2 and 1.0 micromol kg-1 DM, respectively, when plants were exposed to 1,400 micromol m-2 s-1. Levels of ABA in leaves and roots of plants exposed to 100 micromol m-2 s-1 were 0.65 and 0.55 micromol kg-1 DM, respectively. They were 0.24 micromol kg-1 DM (both leaves and roots) when plants were exposed to 1,400 micromol m-2 s-1. Levels of isopentenyl adenosine in leaves (24.3 nmol kg-1 DM) and roots (29.9 nmol kg-1 DM) were not affected by differences in the irradiance regime. Similar values were obtained in a second experiment. Other cytokinins could not be detected (<10 nmol kg 1 DM) in either experiment with the sample sizes used (150-600 mg DM for roots and shoots, respectively).

  10. Decoupling the effects of clear atmosphere and clouds to simplify calculations of the broadband solar irradiance at ground level

    NASA Astrophysics Data System (ADS)

    Oumbe, A.; Qu, Z.; Blanc, P.; Lefèvre, M.; Wald, L.; Cros, S.

    2014-08-01

    In the case of infinite plane-parallel single- and double-layered cloud, the solar irradiance at ground level computed by a radiative transfer model can be approximated by the product of the irradiance under clear atmosphere and a modification factor due to cloud properties and ground albedo only. Changes in clear-atmosphere properties have negligible effect on the latter so that both terms can be calculated independently. The error made in using this approximation depends mostly on the solar zenith angle, the ground albedo and the cloud optical depth. In most cases, the maximum errors (95th percentile) on global and direct surface irradiances are less than 15 W m-2 and less than 2-5% in relative value. These values are similar to those recommended by the World Meteorological Organization for high-quality measurements of the solar irradiance. Practically, the results mean that a model for fast calculation of surface solar irradiance may be separated into two distinct and independent models, possibly abacus-based, whose input parameters and resolutions can be different, and whose creation requires less computation time and resources than a single model.

  11. Effects of low level light irradiation on the migration of mesenchymal stem cells derived from rat bone marrow.

    PubMed

    Li, Wen-Tyng; Chen, Chih-Wei; Huang, Po-Ya

    2013-01-01

    Low level light irradiation (LLLI) was found to exert positive effects on various cells in vitro. The aim of this study was to investigate the effect of LLLI on the migration of rat bone marrow mesenchymal stem cells (rbMSCs). Light irradiation was applied at the energy density of 4 J/cm(2) using red (630 nm) and near infrared (NIR, 850 nm) light emitting diodes (LEDs). Wound healing assay showed both red and NIR light irradiation increased cell mobility. Red and NIR light enhanced transmembrane migration of rbMSCs up to 292.9% and 263.6% accordingly. This agreed with enzymatic activities of MMP-2 and MMP-9 enhanced by irradiation. F-actin accumulation and distribution correlated to increased migration in light-irradiated MSCs. Reactive oxygen species production as well as the expression of pFAK and pNF-кB were elevated after red and NIR LLLI. The study demonstrated that red and NIR LLLI increased rbMSCs migration and identified the phosphorylation of FAK and NF-кB as critical steps for the elevated cell migration upon LLLI. PMID:24110639

  12. Microwave irradiation of rats at 2. 45 GHz activates pinocytotic-like uptake of tracer by capillary endothelial cells of cerebral cortex

    SciTech Connect

    Neubauer, C.; Phelan, A.M.; Kues, H.; Lange, D.G. )

    1990-01-01

    Far-field exposures of male albino rats to 2.45-GHz microwaves (10-microseconds pulses, 100 pps) at a low average power density (10 mW/cm2; SAR approximately 2 W/kg) and short durations (30-120 min) resulted in increased uptakes of tracer through the blood-brain barrier (BBB). The uptake of systemically administered rhodamine-ferritin complex by capillary endothelial cells (CECs) of the cerebral cortex was dependent on power density and on duration of exposure. At 5 mW/cm2, for example, a 15-min exposure had no effect. Near-complete blockade of uptake resulted when rats were treated before exposure to microwaves with a single dose of colchicine, which inhibits microtubular function. A pinocytotic-like mechanism is presumed responsible for the microwave-induced increase in BBB permeability.

  13. Effects of UV-B irradiation on the levels of anthocyanin, rutin and radical scavenging activity of buckwheat sprouts.

    PubMed

    Tsurunaga, Yoko; Takahashi, Tetsuya; Katsube, Takuya; Kudo, Akihide; Kuramitsu, Osamu; Ishiwata, Masaki; Matsumoto, Shingo

    2013-11-01

    The effects of various light compositions on the levels of anthocyanin, rutin and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in buckwheat (Fagopyrum esculentum Moench) sprouts were evaluated. Dark-grown 6-day-old buckwheat sprouts were irradiated with different sources of visible and ultraviolet (UV) light. Particularly, we examined the effect of UV-B at wavelengths of 260-320 nm, 280-320 nm, and 300-320 nm on the production of flavonoid compounds, using multiple fluorescent lights and cylinders that filter out certain portions of the UV-B. The results showed that irradiation with UV-B>300 nm increased the levels of anthocyanin and rutin, as well as the DPPH radical scavenging activity. When sprouts were irradiated with UV-B light at wavelengths of 260-300 nm, yellowing or withering occurred within 24h of irradiation, indicating that wavelengths in this range are detrimental to the growth of buckwheat sprouts. PMID:23768393

  14. Effect of He-Ne laser irradiation on spontaneous contractive activity and basal tone level of rat portal vein

    NASA Astrophysics Data System (ADS)

    Petrishchev, Nikolai N.; Barabanova, Valeria V.; Mikhailova, Irina A.; Chephu, Svetlana G.

    2000-11-01

    To study the effect of He-Ne irradiation (632.8 nm, 15 mW/cm2) on spontaneous contractive activity the fragments of rat portal vein weremounted isometrically in Krebs buffer. Irradiation of vessel fragments by He-Ne laser during 3,5 and 10 min caused the decrease of ton up to 50%, which lasted in postirradiation period (the observation time - 10 min). The frequency of phasic and tonic contractions did not change, but the amplitude increased up to 40% as compared to the initial level. The decreased basal tone level and the increased amplitude of phasic oscillations lasted in postirradiation period. Adding NO synthasa blocator (N - nitro-L-arginine) to Krebs solution before irradiation caused no significant changes mentioned above parameters. Irradiation and coputing of the same parameters of spontaneous contractive activity of vena porta caused no effects, mentioned in the absence of the blocator. From the results it is concluded that the decrease of tone is evoked by the increase of EDRF production and cGMP. The increase of amplitude of phasic and tonic contractions is connected with increase of Ca++ entry in every contraction cycle as a result of membrane Ca++ pool increase.

  15. Effect of microwave radiation on inactivation of Clostridium sporogenes (PA 3679) spores.

    PubMed Central

    Welt, B A; Tong, C H; Rossen, J L; Lund, D B

    1994-01-01

    Three techniques for studying effects of microwave radiation on microorganisms were introduced. Spores of Clostridium sporogenes (PA 3679) were chosen as a test organism because the kinetic parameters for thermal inactivation are well known and because of the importance of the genus Clostridium to the food industry. For the first technique, a specially designed kinetics vessel was used to compare inactivation rates of microwave-heated and conventionally heated spores at steady-state temperatures of 90, 100, and 110 degrees C. Rates were found to be similar at the 95% confidence level. The second and third techniques were designed to study the effect of relatively high power microwave exposure at sublethal temperatures. In the second approach, the suspension was continuously cooled via direct contact with a copper cooling coil in a well-mixed vessel, outside the microwave oven. The suspension was pumped through a Teflon loop in the oven, where it continuously absorbed approximately 400 W of microwave power. Inactivation occurred in both irradiated and unirradiated samples. It was suspected that copper ions entered the suspension from the copper coil and were toxic to the spores. The fact that the results were similar, however, implied the absence of nonthermal microwave effects. In the third approach, the copper coil was replaced with a silicone tubing loop in a microwave transparent vessel. The suspension was continuously irradiated at 150 W of microwave power. No detectable inactivation occurred. Results indicated that the effect of microwave energy on viability of spores was indistinguishable from the effect of conventional heating. PMID:8135512

  16. Comparison of histopathologic changes following X-irradiation of mid-thoracic and lumbosacral levels of neonatal rat spinal cord

    SciTech Connect

    Heard, J.K.; Gilmore, S.A.

    1985-02-01

    Light microscopic changes were studied in the dorsal funiculi of spinal cords from rats irradiated (4000 R) at 3 days of age and killed from 9-60 days postirradiation (P-I). The irradiated site was limited to a 5-mm length of mid-thoracic spinal cord (T only) in one group of rats, to a 5-mm length of lumbosacral spinal cord (L only) in a second group, and to 5-mm lengths of both mid-thoracic and lumbosacral spinal cord (T/L) in the third group. Changes in the lumbosacral regions were essentially the same in both L only and T/L irradiated groups. These changes included a decreased neuroglial population and a concurrent state of hypomyelination from 9-30 days P-I. In contrast, in the mid-thoracic regions of T only and T/L irradiated groups the decrease in the neuroglial population was obvious only through 13 days P-I, and by 30 days this population resembled that of the controls. The irradiated mid-thoracic areas were hypomyelinated, with the fasciculus gracilis showing a greater degree of hypomyelination than the fasciculus cuneatus. By 25 days P-I, myelination appeared to be normal in these areas. Scattered hemorrhages were noted in both lumbosacral and mid-thoracic regions, but necrotic areas occurred only at the lumbosacral level. In general, the mid-thoracic area appeared to be less sensitive to x-radiation at 3 days of age than the lumbosacral area. These data suggest that there may be marked differences in the developmental states of cells at these two levels at 3 days of age.

  17. Thermal stability of deep level defects induced by high energy proton irradiation in n-type GaN

    SciTech Connect

    Zhang, Z.; Farzana, E.; Sun, W. Y.; Arehart, A. R.; Ringel, S. A.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.; McSkimming, B.; Kyle, E. C. H.; Speck, J. S.

    2015-10-21

    The impact of annealing of proton irradiation-induced defects in n-type GaN devices has been systematically investigated using deep level transient and optical spectroscopies. Moderate temperature annealing (>200–250 °C) causes significant reduction in the concentration of nearly all irradiation-induced traps. While the decreased concentration of previously identified N and Ga vacancy related levels at E{sub C} − 0.13 eV, 0.16 eV, and 2.50 eV generally followed a first-order reaction model with activation energies matching theoretical values for N{sub I} and V{sub Ga} diffusion, irradiation-induced traps at E{sub C} − 0.72 eV, 1.25 eV, and 3.28 eV all decrease in concentration in a gradual manner, suggesting a more complex reduction mechanism. Slight increases in concentration are observed for the N-vacancy related levels at E{sub C} − 0.20 eV and 0.25 eV, which may be due to the reconfiguration of other N-vacancy related defects. Finally, the observed reduction in concentrations of the states at E{sub C} − 1.25 and E{sub C} − 3.28 eV as a function of annealing temperature closely tracks the detailed recovery behavior of the background carrier concentration as a function of annealing temperature. As a result, it is suggested that these two levels are likely to be responsible for the underlying carrier compensation effect that causes the observation of carrier removal in proton-irradiated n-GaN.

  18. Functional assessment of high-level laser irradiation. Annual progress report, 1 August 1983-31 December 1984

    SciTech Connect

    Robbins, D.O.

    1985-01-01

    High-energy, Q-switched pulses from a laser are known to produce punctate lesions on the retina. The structural alterations often extend well beyond the primary area of exposure. This report examines the changes in visual sensitivity following single pulses of 532 nm light several orders of magnitude above the ED 50 level. Both temporary and long-term changes in spectral acuity and contrast sensitivity indicate the functional consequences of intense laser irradiation of minute areas of the central fovea.

  19. Deep levels in as-grown and electron-irradiated n-type GaN studied by deep level transient spectroscopy and minority carrier transient spectroscopy

    NASA Astrophysics Data System (ADS)

    Duc, Tran Thien; Pozina, Galia; Son, Nguyen Tien; Kordina, Olof; Janzén, Erik; Ohshima, Takeshi; Hemmingsson, Carl

    2016-03-01

    Development of high performance GaN-based devices is strongly dependent on the possibility to control and understand defects in material. Important information about deep level defects is obtained by deep level transient spectroscopy and minority carrier transient spectroscopy on as-grown and electron irradiated n-type bulk GaN with low threading dislocation density produced by halide vapor phase epitaxy. One hole trap labelled H1 (EV + 0.34 eV) has been detected on as-grown GaN sample. After 2 MeV electron irradiation, the concentration of H1 increases and at fluences higher than 5 × 1014 cm-2, a second hole trap labelled H2 is observed. Simultaneously, the concentration of two electron traps, labelled T1 (EC - 0.12 eV) and T2 (EC - 0.23 eV), increases. By studying the increase of the defect concentration versus electron irradiation fluence, the introduction rate of T1 and T2 using 2 MeV- electrons was determined to be 7 × 10-3 cm-1 and 0.9 cm-1, respectively. Due to the low introduction rate of T1, it is suggested that the defect is associated with a complex. The high introduction rate of trap H1 and T2 suggests that the defects are associated with primary intrinsic defects or complexes. Some deep levels previously observed in irradiated GaN layers with higher threading dislocation densities are not detected in present investigation. It is therefore suggested that the absent traps may be related to primary defects segregated around dislocations.

  20. Furfural Synthesis from d-Xylose in the Presence of Sodium Chloride: Microwave versus Conventional Heating.

    PubMed

    Xiouras, Christos; Radacsi, Norbert; Sturm, Guido; Stefanidis, Georgios D

    2016-08-23

    We investigate the existence of specific/nonthermal microwave effects for the dehydration reaction of xylose to furfural in the presence of NaCl. Such effects are reported for sugars dehydration reactions in several literature reports. To this end, we adopted three approaches that compare microwave-assisted experiments with a) conventional heating experiments from the literature; b) simulated conventional heating experiments using microwave-irradiated silicon carbide (SiC) vials; and at c) different power levels but the same temperature by using forced cooling. No significant differences in the reaction kinetics are observed using any of these methods. However, microwave heating still proves advantageous as it requires 30 % less forward power compared to conventional heating (SiC vial) to achieve the same furfural yield at a laboratory scale. PMID:27416892

  1. Graphite immobilisation in iron phosphate glass composite materials produced by microwave and conventional sintering routes

    NASA Astrophysics Data System (ADS)

    Mayzan, M. Z. H.; Stennett, M. C.; Hyatt, N. C.; Hand, R. J.

    2014-11-01

    An investigation of microwave and conventional processing of iron phosphate based graphite glass composite materials as potential wasteforms for the immobilisation of irradiated graphite is reported. For the base iron phosphate glass, full reaction of the raw materials and formation of a glass melt occurs with consequent removal of porosity at 8 min microwave processing. When graphite is present, iron phosphate crystalline phases are formed with higher levels of residual porosity than in the sample prepared using conventional sintering under argon. It is found that graphite reacts with the microwave field when in powder form but this reaction is minimised when the graphite is incorporated into a pellet, and that the graphite also impedes sintering of the glass. Mössbauer spectroscopy indicates that reduction of iron also occurs with concomitant graphite oxidation. Conventionally sintered samples had lower porosities than the equivalent microwaved ones.

  2. Correlation of proton irradiation induced threshold voltage shifts to deep level traps in AlGaN/GaN heterostructures

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Cardwell, D.; Sasikumar, A.; Kyle, E. C. H.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.; Speck, J. S.; Arehart, A. R.; Ringel, S. A.

    2016-04-01

    The impact of proton irradiation on the threshold voltage (VT) of AlGaN/GaN heterostructures is systematically investigated to enhance the understanding of a primary component of the degradation of irradiated high electron mobility transistors. The value of VT was found to increase monotonically as a function of 1.8 MeV proton fluence in a sub-linear manner reaching 0.63 V at a fluence of 1 × 1014 cm-2. Silvaco Atlas simulations of VT shifts caused by GaN buffer traps using experimentally measured introduction rates, and energy levels closely match the experimental results. Different buffer designs lead to different VT dependences on proton irradiation, confirming that deep, acceptor-like defects in the GaN buffer are primarily responsible for the observed VT shifts. The proton irradiation induced VT shifts are found to depend on the barrier thickness in a linear fashion; thus, scaling the barrier thickness could be an effective way to reduce such degradation.

  3. Quantum coherence and correlations of optical radiation by atomic ensembles interacting with a two-level atom in a microwave cavity

    SciTech Connect

    Muestecaplioglu, Oe.E.

    2011-02-15

    We examine quantum statistics of optical photons emitted from atomic ensembles which are classically driven and simultaneously coupled to a two-level atom via microwave photon exchange. Quantum statistics and correlations are analyzed by calculating second-order coherence degree, von Neumann entropy, spin squeezing for multiparticle entanglement, as well as genuine two- and three-mode entanglement parameters for steady-state and nonequilibrium situations. Coherent transfer of population between the radiation modes and quantum-state mapping between the two-level atom and the optical modes are discussed. A potential experimental realization of the theoretical results in a superconducting coplanar waveguide resonator containing diamond crystals with nitrogen-vacancy color centers and a superconducting artificial two-level atom is discussed.

  4. Electronic properties of deep-level defects in proton irradiated AlGaAs-GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Li, S. S.

    1981-01-01

    Deep level transient spectroscopy and capacitance voltage techniques as well as analysis of the forward current voltage (I-V) characteristics and SEM-EIC data were carried out for proton irradiated GaAs solar cells over a wide range of proton energies and proton fluences. Defect and recombination parameters such as defect energy levels and density, carrier capture cross sections and lifetimes as well as diffusion lengths in the undoped n-GaAs LPE layers were determined. Good correlation between these defect parameters and solar cell performance parameters was obtained for GaAs solar cells irradiated by 200 and 290 KeV protons. It was found that 200 to 290 KeV protons will produce the most defects and damages to the GaAs solar cell structure used. The influence of the low temperature (200 to 400 C) periodic thermal annealing on the deep level defects and the performance of the 200 KeV proton irradiated cells is discussed.

  5. Biophysical model for assessment of risk of acute exposures in combination with low level chronic irradiation

    NASA Astrophysics Data System (ADS)

    Smirnova, O. A.

    A biophysical model is developed which describes the mortality dynamics in mammalian populations unexposed and exposed to radiation The model relates statistical biometric functions mortality rate life span probability density and life span probability with statistical characteristics and dynamics of a critical body system in individuals composing the population The model describing the dynamics of thrombocytopoiesis in nonirradiated and irradiated mammals is also developed this hematopoietic line being considered as the critical body system under exposures in question The mortality model constructed in the framework of the proposed approach was identified to reproduce the irradiation effects on populations of mice The most parameters of the thrombocytopoiesis model were determined from the data available in the literature on hematology and radiobiology the rest parameters were evaluated by fitting some experimental data on the dynamics of this system in acutely irradiated mice The successful verification of the thrombocytopoiesis model was fulfilled by the quantitative juxtaposition of the modeling predictions and experimental data on the dynamics of this system in mice exposed to either acute or chronic irradiation at wide ranges of doses and dose rates It is important that only experimental data on the mortality rate in nonirradiated population and the relevant statistical characteristics of the thrombocytopoiesis system in mice which are also available in the literature on radiobiology are needed for the final identification of

  6. Gamma irradiation of Cryptosporidium parvum oocysts affects intracelluar levels of the viral symbiont CPV

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous studies have shown a dose-dependent effect of gamma irradiation on Cryptosporidium parvum development in neonatal mice and newborn calves. In mice, C. parvum oocysts exposed to 200 Gy showed nearly complete inability to develop as measured by C. parvum-specific quantitative PCR of ileal ti...

  7. Microwave detector

    DOEpatents

    Meldner, Heiner W.; Cusson, Ronald Y.; Johnson, Ray M.

    1986-01-01

    A microwave detector (10) is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite (26, 28) produces a magnetization field flux that links a B-dot loop (16, 20). The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means (18, 22) are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

  8. Microwave detector

    DOEpatents

    Meldner, H.W.; Cusson, R.Y.; Johnson, R.M.

    1985-02-08

    A microwave detector is provided for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations. A biased ferrite produces a magnetization field flux that links a B-dot loop. The magnetic field of the microwave pulse participates in the formation of the magnetization field flux. High-frequency insensitive means are provided for measuring electric voltage or current induced in the B-dot loop. The recorded output of the detector is proportional to the time derivative of the square of the envelope shape of the microwave pulse.

  9. Microwave-assisted digestion followed by parallel electromembrane extraction for trace level perchlorate detection in biological samples.

    PubMed

    Nsubuga, Hakimu; Basheer, Chanbasha; Bushra, Mohanad Mubashar; Essa, Mohammed Hussain; Omar, Mohammed Hussain; Shemsi, Ahsan Mushir

    2016-02-15

    A simple and parallel electromembrane extraction (pEME) method was developed and used to investigate trace perchlorate ion contamination in seafood. In this method, three different EME units were arranged simultaneously and connected parallel to a single DC power supply. In each unit, the ClO4(-) ions were electro-kinetically extracted from the microwave digested seafood homogenates into 100mM NaOH via a supported liquid membrane (1-Hexanol). Influential extraction parameters were carefully investigated. Under optimized conditions, good linearity with a coefficient of determination (R(2)) of 0.9949 over a concentration range of 1-125μg/g was obtained. The limit of detection (LOD) was 0.04μgg(-1). The methods intraday and inter day precision varied between 4.3-5.6% respectively. Mean recoveries were up to 107% (n=6, RSD=0.7-6.8%). This method was applied to different seafood samples to assess its feasibility for real applications and it exhibited an enhanced sample throughput compatible with both microwave and ion chromatography. PMID:26797491

  10. Analysis of generation and annihilation of deep level defects in a silicon-irradiated bipolar junction transistor

    NASA Astrophysics Data System (ADS)

    Madhu, K. V.; Kulkarni, S. R.; Ravindra, M.; Damle, R.

    2007-08-01

    A commercial bipolar junction transistor (2 N 2219 A, npn), irradiated with 120 MeV Si9+ ions with a fluence of the order of 1012 ions cm-2, is studied for radiation-induced gain degradation and deep level defects. I-V measurements are made to study the gain degradation as a function of ion fluence. Properties such as activation energy, trap concentration and capture cross section of deep levels are studied by deep level transient spectroscopy (DLTS). Minority carrier trap energy levels with energies ranging from EC - 0.160 eV to EC - 0.581 eV are observed in the base-collector junction of the transistor. Majority carrier trap levels are also observed with energies ranging from EV + 0.182 eV to EV + 0.401 eV. The identification of the defect type is made on the basis of its finger prints such as activation energy, annealing temperature and capture cross section by comparing with those reported in the literature. New energy levels for the defects A-center, di-vacancy and Si-interstitial are also observed. The irradiated transistor is subjected to isothermal and isochronal annealing. The defects are seen to anneal above 250 °C. The defects generated in the base region of the transistor by displacement damage appear to be responsible for transistor gain degradation.

  11. Behavioral effects of microwaves

    SciTech Connect

    Stern, S.

    1980-01-01

    Microwaves can produce sensations of warmth and sound in humans. In other species, they also can serve as cues, they may be avoided, and they can disrupt ongoing behavior. These actions appear to be due to heat produced by energy absorption. The rate of absorption depends on the microwave parameters and the electrical and geometric properties of the subject. We therefore, cannot predict the human response to microwaves based on data from other animals without appropriate scaling considerations. At low levels of exposure, microwaves can produce changes in behavior without large, or even measureable, changes in body temperature. Thermoregulatory behavior may respond to those low levels of heat, and thereby affect other behavior occurring concurrently. There are no data that demonstrate that behavioral effects of microwaves depend on any mechanism other than reactions to heat. Our interpretation of whether a reported behavioral effect indicates that microwaves may be hazardous depends on our having a complete description of the experiment and on our criteria of behavioral toxicity.

  12. The microwave-assisted photo-catalytic degradation of organic dyes.

    PubMed

    Jung, S C

    2011-01-01

    In this study, TiO(2) photo-catalyst balls produced by the chemical vapour deposition method were used for degradation of organic dyes in which simultaneous irradiation of microwave and UV was evaluated. An electrodeless UV lamp that emits UV upon the irradiation of microwave was developed to irradiate microwave and UV simultaneously. The degradation reaction rate was shown to be higher with higher microwave intensity, under stronger acidic or basic conditions, and with a larger amount of O(2) gas or H(2)O(2) addition. The effect of addition of H(2)O(2) was not significant when photo-catalysis was used without additional microwave irradiation or when microwave was irradiated without the use of photo-catalysts. When H(2)O(2) was added under simultaneous use of photo-catalysis and microwave irradiation, however, considerably higher degradation reaction rates were observed. PMID:21508555

  13. Selection of biological indicator for validating microwave heating sterilization.

    PubMed

    Sasaki, K; Mori, Y; Honda, W; Miyake, Y

    1998-01-01

    For the purpose of selecting an appropriate biological indicator for evaluation of the effects of microwave heating sterilization, we examined aerobic bacterial spores to determine whether microwaves have non-thermal sterilization effects. After microwave irradiation on dry bacterial spores (three species), none of the bacterial spores were killed. The survival rate of the spores after microwave irradiation of spore suspensions (twelve species) was compared with that after heating by a conventional method. The order of heat resistance in the bacterial species was similar between the two heating methods. Bacillus stearothermophilus spores were the most heat-resistant. These results suggest that microwaves have no non-thermal sterilization effects on bacterial spores, the specific resistant spores to microwave heating, and microwave heating sterilization can be evaluated in the same way as for conventional heating sterilization. As a biological indicator for evaluation of overkill sterilization, B. stearothermophilus spores may be appropriate for microwave heating sterilization as well as steam sterilization. PMID:9610169

  14. Photobiostimulation on chondrocytes proliferation in different concentration of fetal bovine serum under low-level laser irradiation

    NASA Astrophysics Data System (ADS)

    Zheng, Liqin; Wang, Yuhua; Qiu, Caimin; Chen, Jianlin; Yang, Hongqin; Zhang, Yanding; Xie, Shusen

    2015-03-01

    The aim of this in vitro study was to evaluate the influence of low-level laser irradiation (LLLI) on the chondrocytes proliferation cultured in different concentration of fetal bovine serum (FBS) using 658 nm, 785 nm and 830 nm diode lasers. The role of energy density (10-70 mJ·cm-2) on chondrocytes proliferation following irradiation with 658 nm laser for 2 days was firstly investigated to find out the best laser energy density. Then the effect of LLLI on the proliferation of chondrocytes cultured with fetal bovine serum at 0%, 2%, 5% and 10% was also evaluated. The results showed that there was no or little photobiostimulation on the proliferation of chondrocytes cultured with 0% FBS and 10% FBS; the cell proliferation at 2% and 5% FBS was significantly modulated by LLLI.

  15. BEHAVIORAL AND PHYSIOLOGICAL EFFECTS OF CHRONIC 2,450-MHZ MICROWAVE IRRADIATION OF THE RAT AT 0.5 MW/CM SQ

    EPA Science Inventory

    Adult male Long-Evans rats were intermittently exposed to 2450 MHz CW microwaves at an average power density of 0.5 mW/sq. cm. for 90 days. The resulting SAR was 0.14 W/kg (range 0.11 to 0.18 W/kg). The animals were exposed 7 h/day, 7 days/wk, for a total of 630 h in a monopole-a...

  16. TERATOGENIC EFFECTS OF MICROWAVE RADIATION

    EPA Science Inventory

    Pregnant CF-1 mice was exposed to 2450-MHz CW microwave irradiation at power densities of 0, 10, or 30 mW/sq. cm for 6 hours daily from gestational day 1 through day 18. All exposures occurred in an anechoic chamber maintained at 50% relative humidity with air temperature of 22C....

  17. Thermal basis for disruption of operant behavior by microwaves in three animal species

    SciTech Connect

    de Lorge, J.O.

    1982-06-01

    A large variety of microwave producing devices are used in contemporary naval communications and weapons systems. Public and scientific concern about potential biological effects of microwave irradiation such as produced by these various devices requires documentations of such effects. Currently, the only well documented direct effect of microwaves is heating of the exposed organism. The present report is of a series of studies whose aim was to explore several microwave frequencies and their effect on performance and simultaneously to investigate the relationship to core heating in the exposed animals. Three difficult sized species of animals were used so that generalization to larger animals could be made. Rats, squirrel monkeys, and rhesus monkeys showed consistent effects of 60-minute exposures to microwaves when their body temperatures were increased at least 1 C above baseline temperatures. Performance was not reliably affected when body temperatures remained below this level. Greater intensities of microwaves were required to influence the animals' temperature and behavior as the animal size increased. A direct relationship between frequency and power density was observed in the rhesus monkey; e. g., as the frequency of the microwaves increased, the power density needed to affect behavior and temperature also increased.

  18. Microwave heating enhances antioxidant and emulsifying activities of ovalbumin glycated with glucose in solid-state.

    PubMed

    Tu, Zong-Cai; Hu, Yue-Ming; Wang, Hui; Huang, Xiao-Qin; Xia, Shi-Qi; Niu, Pei-Pei

    2015-03-01

    The aim of this study was to characterize the properties of ovalbumin (OVA) after glycated with glucose under microwave heating. For this purpose, microwave at 480 and 640 W power levels were used for heating the OVA-glucose system in solid-state for 0, 5, 10, 15, 20 and 25 min, respectively. The results indicated that the protein molecular weight was increased after glycated with glucose under microwave treatment, the pH of the system was decreased with the increase of microwave treatment power and time, while the UV absorbance, browning intensity, antioxidant activities as well as the emulsifying activity and emulsion stability of the Maillard reaction products (MRPs) were increased in according with the raise of microwave treatment power and time. The reaction time of microwave treatment is much shorter than those using traditional methods, suggesting that microwave irradiation is a novel and efficient approach to promote Maillard reaction (MR) in dry state and improve protein antioxidant and functional properties. PMID:25745213

  19. Microwave-mediated enzymatic modifications of DNA.

    PubMed

    Das, Rakha Hari; Ahirwar, Rajesh; Kumar, Saroj; Nahar, Pradip

    2015-02-15

    Here we report microwave-induced specific cleavage, ligation, dephosphorylation, and phosphorylation of nucleic acids catalyzed by restriction endonucleases, T4 DNA ligase, T4 polynucleotide kinase, and calf intestinal alkaline phosphatase. The microwave-mediated method has dramatically reduced the reaction time to 20 to 50s. In control experiments, the same reactions failed to give the desired reaction products when carried out in the same time periods but without microwave irradiation. Because the microwave method is rapid, it could be a useful alternative to the time-consuming conventional procedure for enzymatic modification of DNA. PMID:25447491

  20. Measuring the dynamics of cyclic adenosine monophosphate level in living cells induced by low-level laser irradiation using bioluminescence resonance energy transfer.

    PubMed

    Huang, Yimei; Zheng, Liqin; Yang, Hongqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen; Zeng, Haishan

    2015-05-01

    Several studies demonstrated that the cyclic adenosine monophosphate (cAMP), an important second messenger, is involved in the mechanism of low-level laser irradiation (LLLI) treatment. However, most of these studies obtained the cAMP level in cell culture extracts or supernatant. In this study, the cAMP level in living cells was measured with bioluminescence resonance energy transfer (BRET). The effect of LLLI on cAMP level in living cells with adenosine receptors blocked was explored to identify the role of adenosine receptors in LLLI. The results showed that LLLI increased the cAMP level. Moreover, the rise of cAMP level was light dose dependent but wavelength independent for 658-, 785-, and 830-nm laser light. The results also exhibited that the adenosine receptors, a class of G protein-coupled receptor (GPCR), modulated the increase of cAMP level induced by LLLI. The cAMP level increased more significantly when the A3 adenosine receptors (A3R) were blocked by A3R antagonist compared with A1 adenosine receptor or A2a adenosine receptor blocked in HEK293T cells after LLLI, which was in good agreement with the adenosine receptors’ expressions. All these results suggested that measuring the cAMP level with BRET could be a useful technique to study the role of GPCRs in living cells under LLLI. PMID:25611980

  1. Measuring the dynamics of cyclic adenosine monophosphate level in living cells induced by low-level laser irradiation using bioluminescence resonance energy transfer

    NASA Astrophysics Data System (ADS)

    Huang, Yimei; Zheng, Liqin; Yang, Hongqin; Chen, Jiangxu; Wang, Yuhua; Li, Hui; Xie, Shusen; Zeng, Haishan

    2015-05-01

    Several studies demonstrated that the cyclic adenosine monophosphate (cAMP), an important second messenger, is involved in the mechanism of low-level laser irradiation (LLLI) treatment. However, most of these studies obtained the cAMP level in cell culture extracts or supernatant. In this study, the cAMP level in living cells was measured with bioluminescence resonance energy transfer (BRET). The effect of LLLI on cAMP level in living cells with adenosine receptors blocked was explored to identify the role of adenosine receptors in LLLI. The results showed that LLLI increased the cAMP level. Moreover, the rise of cAMP level was light dose dependent but wavelength independent for 658-, 785-, and 830-nm laser light. The results also exhibited that the adenosine receptors, a class of G protein-coupled receptor (GPCR), modulated the increase of cAMP level induced by LLLI. The cAMP level increased more significantly when the A3 adenosine receptors (A3R) were blocked by A3R antagonist compared with A1 adenosine receptor or A2a adenosine receptor blocked in HEK293T cells after LLLI, which was in good agreement with the adenosine receptors' expressions. All these results suggested that measuring the cAMP level with BRET could be a useful technique to study the role of GPCRs in living cells under LLLI.

  2. Microwave effects on plasmid DNA

    SciTech Connect

    Sagripanti, J.L.; Swicord, M.L.; Davis, C.C.

    1987-05-01

    The exposure of purified plasmid DNA to microwave radiation at nonthermal levels in the frequency range from 2.00 to 8.75 GHz produces single- and double-strand breaks that are detected by agarose gel electrophoresis. Microwave-induced damage to DNA depends on the presence of small amounts of copper. This effect is dependent upon both the microwave power and the duration of the exposure. Cuprous, but not cupric, ions were able to mimic the effects produced by microwaves on DNA.

  3. Threshold Level of p53 Required for the Induction of Apoptosis in X-Irradiated MOLT-4 Cells

    SciTech Connect

    Nakano, Hisako . E-mail: nakano@rinshoken.or.jp; Yonekawa, Hiromichi; Shinohara, Kunio

    2007-07-01

    Purpose: To determine the threshold level for the initiation of apoptosis by studying the quantitative aspect of p53 response to DNA damage in individual cells, to better understand the process in X-ray-induced p53-dependent apoptosis. Methods and Materials: Time-sequential changes in p53 protein level were obtained for X-irradiated MOLT-4 cells using flow cytometry and analyzed. Results: The changes in the cellular frequency distribution pattern of p53 content could be divided into two parts at a certain p53 level. The p53 vs. side-scatter in flow cytometry showed the sequential changes of p53 increase followed by an increase in cell death. On the basis of these results we determined a threshold level of p53 for the initiation of apoptosis. The level was estimated to be (1.08 {+-} 0.05) x 10{sup 5} molecules per cell, which was approximately threefold higher than the mean content of control cells. The minimum times for p53 level to reach this threshold level were independent of X-ray dose and 1.4-1.6 h. The times for the signal transduction from the p53 accumulation to disruption of the mitochondrial membrane potential, caspase-3 activation, and cell death were 1.6, 2.1, and 2.8 h, respectively. Conclusions: The threshold level of p53 for the initiation of apoptosis and the time sequence in the course of apoptotic events were determined in X-irradiated MOLT-4 cells.

  4. Paramecium tetraurelia growth stimulation under low-level chronic irradiation: investigations on a possible mechanism. [/sup 60/Co

    SciTech Connect

    Croute, F.; Soleilhavoup, J.P.; Vidal, S.; Dupouy, D.; Planel, H.

    1982-12-01

    Experiments were carried out to demonstrate the effects of low-level chronic irradiation on Paramecium tetraurelia proliferation. Biological effects were strongly dependent on the bacterial density of culture medium and more exactly on the catalase content of the medium. Significant growth stimulation was found under /sup 60/Co chronic irradiation at a dose rate of 2 rad/year when paramecia were grown in a medium containing a high bacterial concentration (2.5 x 10/sup 2/ cells/m) or supplemented with catalase (300 U/ml). In a medium with a low bacterial density (1 x 10/sup 6/ cell/ml) or supplemented with a catalase activity inhibitor, growth simulation was preceded by a transitory inhibiting effect which could be correlated with extracellularly radioproduced H/sub 2/O/sub 2/. H/sub 2/O/sub 2/ addition appeared to be able to simulate the biological effects of chronic irradiation. A possible mechanism is discussed.We proposed that the stimulating effects were the result of intracellular enzymatic scavenging of radioproduced H/sub 2/O/sub 2/.

  5. Different doses of low-level laser irradiation modulate the in vitro response of osteoblast-like cells

    NASA Astrophysics Data System (ADS)

    Incerti Parenti, Serena; Checchi, Luigi; Fini, Milena; Tschon, Matilde

    2014-10-01

    Because osteoblasts play a key role in bone remodeling and the influence of low-level laser therapy on this process is not clear, Saos-2 human osteoblast-like cells were irradiated by a gallium-aluminum-arsenide diode laser (915 nm) for 10, 48, 96, 193, and 482 s using doses 1, 5, 10, 20, and 50 J/cm2, respectively. A control group was not irradiated. Morphology, viability, and cytotoxicity analyses were carried out after 1 hr, 1 day, and 3 days. Deoxyribose nucleic acid (DNA) content and release of vascular endothelial growth factor (VEGF), receptor activator of nuclear factor kappa B ligand (RANKL), and osteoprotegerin (OPG) were evaluated. Viability was modulated by laser irradiation in a dose-dependent manner, with 10 J/cm2 inducing a biostimulatory response and 20 to 50 J/cm2 determining a bioinhibitory and cytotoxic effect. Accordingly, DNA content was generally increased for the 10 J/cm2 dose and decreased for the 50 J/cm2 dose. A rapid and transitory trend toward increased RANKL/OPG ratio and a tendency toward a delayed increase in VEGF release for doses of 1 to 10 J/cm2 was found. Further investigations using the biostimulatory dose of 10 J/cm2 emerged from this study are needed to establish the ideal treatment regimens in the laboratory as well as in clinical practice.

  6. Caffeine enhanced measurement of mutagenesis by low levels of [gamma]-irradiation in human lymphocytes

    SciTech Connect

    Puck, T.P.; Johnson, R.; Waldren, C.A. ); Morse, H. )

    1993-09-01

    The well-known action of caffeine in synergizing mutagenesis (including chromosome aberrations) of agents like ionizing radiation by inhibition of cellular repair processes has been incorporated into a rapid procedure for detection of mutagenicity with high sensitivity. Effects of 5-10 rads of [gamma]-irradiation, which approximate the human lifetime dose accumulation from background radiation, can be detected in a two-day procedure using an immortalized human WBC culture. Chromosomally visible lesions are scored on cells incubated for 2 h after irradiation in the presence and absence of 1.0 mg/ml of caffeine. An eightfold amplification of scorable lesions is achieved over the action of radiation alone. This approach provides a closer approximation to absolute mutagenicity unmitigated by repair processes, which can vary in different situations. It is proposed that mutagenesis testing of this kind, using caffiene or other repair-inhibitory agents, be employed to identify mutagens in their effective concentrations to which human populations may be exposed; to detect agents such as caffeine that may synergize mutagenic actions and pose epidemiologic threats; and to discover effective anti-mutagens. Information derived from the use of such procedures may help prevent cancer and newly acquired genetic disease.

  7. Deployment of Cesium Recovered from High Level Liquid Waste for Irradiation - Indian Scenario - 13128

    SciTech Connect

    Vincent, Tessy; Shah, J.G.; Kumar, Amar; Patil, S.B.; Wattal, P.K.

    2013-07-01

    Recovery of Cs-137 from HLW and its utilisation as source pencil in place of Co-60 is vital for medical and sewage treatment applications in India. For separation of Cs, specific ion exchange resins as well as 'Calyx crown' solvent have been developed and synthesized indigenously. A flow sheet involving separation of Cs from acidic HLW using Ammonium Molybdo Phosphate (AMP) resins, recovery of Cs from the loaded AMP column by dissolving it in alkali, ion exchange purification of Cs rich alkaline solution using Resorcinol-Formaldehyde Poly condensate (RF) resins and its elution in cesium nitrate form was developed and demonstrated. Solvent extraction route employing 0.03 Molar, 1-3-octyl oxy Calyx (4) arene crown-6 in 30% isodecyl alcohol and dodecane was also established using mixer settlers. Cesium lithium borosilicate glass based formulations have been considered as a glass matrix for Cs irradiation pencils. While choosing this vitreous matrix, attributes addressing maximum possible Cs-137 loading, low glass pouring temperature to minimise Cs volatility, reasonably good mechanical strength and good chemical durability have been considered. Recovered cesium nitrate solution was vitrified along with glass additives in an induction heated metallic melter and subsequently poured into 12 numbers of Cs irradiation pencils positioned on turn-table equipped with the load cell. The complete cycle involving recovery of Cs from HLW followed by its conversion into Cs pencil was demonstrated. (authors)

  8. Temperature dependence of contact resistance for Au-Ti-Pd{sub 2}Si-n{sup +}-Si ohmic contacts subjected to microwave irradiation

    SciTech Connect

    Belyaev, A. E.; Boltovets, N. S.; Konakova, R. V. Kudryk, Ya. Ya.; Sachenko, A. V.; Sheremet, V. N.; Vinogradov, A. O.

    2012-03-15

    Based on a theoretical analysis of the temperature dependence of the contact resistance R{sub c} for an Au-Ti-Pd{sub 2}Si-n{sup +}-Si ohmic contact, a current-transfer mechanism explaining the experimentally observed increase in R{sub c} in the temperature range 100-380 K is proposed. It is shown that microwave treatment of such contacts results in a decrease in the spread of R{sub c} over the wafer and a decrease in the value of R{sub c} whilst retaining an increase in R{sub c} in the temperatures range 100-380 K.

  9. Study of radiation induced deep-level defects in proton irradiated AlGaAs-GaAs solar cells

    NASA Technical Reports Server (NTRS)

    Li, S. S.

    1980-01-01

    Radiation induced deep-level defects (both electron and hole traps) in proton irradiated AlGaAs-GaAs p-n junction solar cells are investigated along with the correlation between the measured defect parameters and the solar cell performance parameters. The range of proton energies studied was from 50 KeV to 10 MeV and the proton fluence was varied from 10 to the 10th power to 10 to the 13th power P/sq cm. Experimental tools employed include deep-level transient spectroscopy, capacitance-voltage, current voltage, and SEM-EBIC methods. Defect and recombination parameters such as defect density and energy level, capture cross section, carrier lifetimes and effective hole diffusion lengths in n-GaAs LPE layers were determined from these measurements.

  10. Immunobiological effect of bitemporal exposure of rabbits to microwaves

    SciTech Connect

    Bogolyubov, V.M.; Pershin, S.B.; Frenkel', I.D.; Sidorov, V.D.; Galenchik, A.I.; Ponomarev, Yu.T.; Bobkova, A.S.; Kuz'min, S.N.; Moshiashvili, I.Ya.; Kozlova, N.N.; Korovkina, E.G.; Agibalov, Yu.V.

    1987-01-01

    The authors investigate the effects of microwave radiation on the immunological behavior of the thyroid and various hormones of rabbits. Irradiation was carried out on the heads of the animals. They were then divided into four groups depending on the period of exposure. The number of hemolysis-forming cells against sheep red blood cells and the concentration of serum immunoglobulins were determined. Levels of TSH, triiodothyronine, thyroxine, testosterone and prostaglandins in serum or blood plasma were determined by radioimmunoassay and the concentration of total 11-hydroxycorticosteroids in the adrenals and plasma were determined by fluorimetry. Microwave radiation of the temporo-parietal region of the head was found to decrease the number of background hemolysis-forming cells. An increase in glucocorticoid function was recorded. Thyroid function was depressed. The plasma 11-hydroxycorticosteroid level was significantly raised. It is concluded in general that microwave irradiation leads to activation of the hypothalamo-hypophyseo-adrenal system with consequent enhancement of the glucocorticoid function of the adrenal cortex and depression of thyroid function.

  11. [Effects of light irradiation on phosphorous releases from typical submerged soils of water-level fluctuation zones of Three Gorges Reservoirs areas].

    PubMed

    Guo, Nian; Jiang, Tao; Wei, Shi-Qiang; Yan, Jin-Long; Liang, Jian; Lu, Song; Gao, Jie

    2014-12-01

    For understanding the impact of light irradiation on the phosphorus (P) releases from soil-water interface, two types of typical soils sampled from water-level fluctuation zones of Three Gorges Reservoir areas were selected as research objectives, and simulated light irradiation experiment in lab was conducted for unveiling the underlying mechanisms of P releases from submerged soils in the presence of light irradiation. The results showed that light irradiation could inhibit P releases from submerged soils by a certain degree. Under light condition, total P (TP) concentrations in underlying water of submerged purple soil ranged from 0.018 to 0.033 mg x L(-1), as compared to the range of 0.02-0.057 mg x L(-1) in darkness treatment. Additionally, for gray-brown purple soil, TP was in a range of 0.028-0.045 mg x L(-1) when light irradiated, but in the range of 0.04-0. 084 mg x L(-1) under darkness condition. Meanwhile, changes of iron oxides in soils due to light irradiation were possibly to be the important reason to explain the inhabitation of light irradiation on P releases. Moreover, light irradiation resulted in decreasing saturation degree of iron oxides in soils, which further inhibited the iron reduction and production of amorphous iron, further enhanced the underlying mechanisms of decreasing P releases in presence of light irradiation. Further, CO2 and CH4 could reflect decomposition of soil organic carbon (SOC) in submerged condition. Light irradiation significantly decreased SOC transformation into carbon gases. Stimulating consumption of inorganic electron acceptors in submerged soils could also be used to explain the changes of iron oxides under light irradiation condition. Thus, inhabitation of light irradiation on P releases from submerged soils obviously related with iron minerals reduction and decomposition of organic matter in soils. PMID:25826924

  12. Evaluation of damage induced by high irradiation levels on α-Ni-Ni3Si eutectic structure

    NASA Astrophysics Data System (ADS)

    Camacho Olguin, Carlos Alberto; Garcia-Borquez, Arturo; González-Rodríguez, Carlos Alberto; Loran-Juanico, Jose Antonio; Cruz-Mejía, Hector

    2015-06-01

    to 380 dpa at 650°C in a Tandetron linear accelerator. The level of irradiation dose was chosen similar to the irradiation conditions of the next-generation nuclear reactors. The theoretical maximum depth of the DII (maximum depth of damage (MDD)) was calculated as 1.35 µm using the SRIM-2013 program; the laminar microstructure of the eutectic was simulated using the lattice parameters of the eutectic before irradiation. The experimental MDD was 1.47 µm, as determined through transmission electron microscope (TEM) images and the DII was characterized using µX-ray diffraction and TEM. The elimination of cubic phase of the intermetallic Ni3Si, the suppression of lamellae of the α-Ni phase, the generation of dislocation loops and lines, all of these changes generated by the irradiation are clear evidences that the DII was severe. Based on theoretical and experimental evidence, we propose that the amount of phases, alternate of lamellae with different chemical concentrations of silicon and lamellae spatial distribution have a direct relation with the severe evolution of the DII.

  13. Proteomic and Metabolomic Analyses of Leaf from Clematis terniflora DC. Exposed to High-Level Ultraviolet-B Irradiation with Dark Treatment.

    PubMed

    Yang, Bingxian; Wang, Xin; Gao, Cuixia; Chen, Meng; Guan, Qijie; Tian, Jingkui; Komatsu, Setsuko

    2016-08-01

    Clematis terniflora DC. has potential pharmaceutical value; on the contrary, high-level UV-B irradiation with dark treatment led to the accumulation of secondary metabolites. Metabolomic and proteomic analyses of leaf of C. terniflora were performed to investigate the systematic response mechanisms to high-level UV-B irradiation with dark treatment. Metabolites related to carbohydrates, fatty acids, and amino acids and/or proteins related to stress, cell wall, and amino acid metabolism were gradually increased in response to high-level UV-B irradiation with dark treatment. On the basis of cluster analysis and mapping of proteins related to amino acid metabolism, the abundances of S-adenosylmethionine synthetase and cysteine synthase as well as 1,1-diphenyl-2-picrylhydrazyl scavenging activity were gradually increased in response to high-level UV-B irradiation with dark treatment. Furthermore, the abundance of dihydrolipoyl dehydrogenase/glutamate dehydrogenase and the content of γ-aminobutyric acid were also increased following high-level UV-B irradiation with dark treatment. Taken together, these results suggest that high-level UV-B irradiation with dark treatment induces the activation of reactive oxygen species scavenging system and γ-aminobutyric acid shunt pathway in leaf of C. terniflora. PMID:27323210

  14. Microwave generator

    SciTech Connect

    Kwan, T.J.T.; Snell, C.M.

    1987-03-31

    A microwave generator is provided for generating microwaves substantially from virtual cathode oscillation. Electrons are emitted from a cathode and accelerated to an anode which is spaced apart from the cathode. The anode has an annular slit there through effective to form the virtual cathode. The anode is at least one range thickness relative to electrons reflecting from the virtual cathode. A magnet is provided to produce an optimum magnetic field having the field strength effective to form an annular beam from the emitted electrons in substantial alignment with the annular anode slit. The magnetic field, however, does permit the reflected electrons to axially diverge from the annular beam. The reflected electrons are absorbed by the anode in returning to the real cathode, such that substantially no reflexing electrons occur. The resulting microwaves are produced with a single dominant mode and are substantially monochromatic relative to conventional virtual cathode microwave generators. 6 figs.

  15. Orthogonal array design as a chemometric method for the optimization of analytical procedures. Part 5. Three-level design and its application in microwave dissolution of biological samples.

    PubMed

    Lan, W G; Wong, M K; Chen, N; Sin, Y M

    1995-04-01

    The theory and methodology of a three-level orthogonal array design as a chemometric method for the optimization of analytical procedures were developed. In the theoretical section, firstly, the matrix of a three-level orthogonal array design is described and orthogonality is proved by a quadratic regression model. Next, the assignment of experiments in a three-level orthogonal array design and the use of the triangular table associated with the corresponding orthogonal array matrix are illustrated, followed by the data analysis strategy, in which significance of the different factor effects is quantitatively evaluated by the analysis of variance (ANOVA) technique and the percentage contribution method. Then, a quadratic regression equation representing the response surface is established to estimate each factor that has a significant influence. Finally, on the basis of the quadratic regression equation established, the derivative algorithm is used to find the optimum value for each variable considered. In the application section, microwave dissolution for the determination of selenium in biological samples by hydride generation atomic absorption spectrometry is employed, as a practical example, to demonstrate the application of the proposed three-level orthogonal array design in analytical chemistry. PMID:7771675

  16. UV-B irradiation alleviates the deterioration of cold-stored mangoes by enhancing endogenous nitric oxide levels.

    PubMed

    Ruan, Jiazhao; Li, Mengya; Jin, Haihong; Sun, Lina; Zhu, Yun; Xu, Maojun; Dong, Jufang

    2015-02-15

    Effects of UV-B radiation on chilling injury, ripening and endogenous nitric oxide (NO) levels in mango fruit were evaluated. Chilling injury index, ion leakage, and malondialdehyde (MDA) content of the fruit pretreated with 5kJm(-2) UV-B for 4h were significantly lower than those of the control during fruit ripening at ambient temperature following cold storage at 6°C for 10days. Fruit firmness of the mangoes irradiated with UV-B was significantly higher than the control during the ripening period. Endogenous NO levels of the UV-B-irradiated fruit were rapidly increased after UV-B treatment. Pre-treatment of mangoes with the NO specific scavenger, not only abolished UV-B-triggered NO accumulation, but also suppressed the UV-B-reduced chilling injury, oxidative damage, and ripening delay of the fruit. Together, the results suggest that UV-B treatment may enhance chilling tolerance and delay fruit ripening of mangoes by triggering endogenous NO generation in the fruit. PMID:25236246

  17. Microwave radiation (2450 MHz) alters the endotoxin-induced hypothermic response of rats

    SciTech Connect

    Smialowicz, R.J.; Compton, K.L.; Riddle, M.M.; Rogers, R.R.; Brugnolotti, P.L.

    1980-01-01

    The parenteral administration of bacterial endotoxin to rats causes a hypothermia that is maximal after approximately 90 minutes. When endotoxin-injected rats were held in a controlled environment at 22 degree C and 50% relative humidity and exposed for 90 minutes to microwaves (2450 MHz, CW) at 1 mW/cm2, significant increases were observed in body temperature compared with endotoxin-treated, sham-irradiated rats. The magnitude of the response was related to power density (10 mW/cm2 greater than 5 mW/cm2 greater than 1 mW/cm2). Saline-injected rats exposed for 90 minutes at 5 mW/cm2 (specific absorption rate approximately 1.0 mW/g) showed no significant increase in body temperature compared with saline-injected, sham-irradiated rats. The hypothermia induced by endotoxin in rats was also found to be affected by ambient temperature alone. Increases in ambient temperature above 22 degree C in the absence of microwaves caused a concomitant increase in body temperature. This study reveals that subtle microwave heating is detectable in endotoxin-treated rats that have impaired thermoregulatory capability. These results indicate that the interpretation of microwave-induced biological effects observed in animals at comparable rates and levels of energy absorption should include a consideration of the thermogenic potential of microwave.

  18. Microwave-Assisted Rapid Enzymatic Synthesis of Nucleic Acids.

    PubMed

    Hari Das, Rakha; Ahirwar, Rajesh; Kumar, Saroj; Nahar, Pradip

    2016-07-01

    Herein we report microwave-induced enhancement of the reactions catalyzed by Escherichia coli DNA polymerase I and avian myeloblastosis virus-reverse transcriptase. The reactions induced by microwaves result in a highly selective synthesis of nucleic acids in 10-50 seconds. In contrast, same reactions failed to give desired reaction products when carried out in the same time periods, but without microwave irradiation. Each of the reactions was carried out for different duration of microwave exposure time to find the optimum reaction time. The products produced by the respective enzyme upon microwave irradiation of the reaction mixtures were identical to that produced by the conventional procedures. As the microwave-assisted reactions are rapid, microwave could be a useful alternative to the conventional and time consuming procedures of enzymatic synthesis of nucleic acids. PMID:27159147

  19. Solid-phase synthesis of graphene quantum dots from the food additive citric acid under microwave irradiation and their use in live-cell imaging.

    PubMed

    Zhuang, Qianfen; Wang, Yong; Ni, Yongnian

    2016-05-01

    The work demonstrated that solid citric acid, one of the most common food additives, can be converted to graphene quantum dots (GQDs) under microwave heating. The as-prepared GQDs were further characterized by various analytical techniques like transmission electron microscopy, atomic force microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, fluorescence and UV-visible spectroscopy. Cytotoxicity of the GQDs was evaluated using HeLa cells. The result showed that the GQDs almost did not exhibit cytotoxicity at concentrations as high as 1000 µg mL(-1) . In addition, it was found that the GQDs showed good solubility, excellent photostability, and excitation-dependent multicolor photoluminescence. Subsequently, the multicolor GQDs were successfully used as a fluorescence light-up probe for live-cell imaging. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26310294

  20. Eco-friendly and green synthesis of BiVO4 nanoparticle using microwave irradiation as photocatalayst for the degradation of Alizarin Red S

    NASA Astrophysics Data System (ADS)

    Abraham, S. Daniel; David, S. Theodore; Bennie, R. Biju; Joel, C.; Kumar, D. Sanjay

    2016-06-01

    Bismuth vanadate (BiVO4) nanocrystals have been successfully synthesised using microwave-assisted combustion synthesis (MCS), and characterised using Fourier transform infrared (FT-IR) and Raman spectra, surface area analysis (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), Energy Dispersive X-ray analysis (EDX), diffused reflectance spectroscopy (DRS) and Photoluminescence (PL) spectroscopy. The XRD results confirmed the formation of monoclinic bismuth vanadate. The formations of BiO & VO43-vibrations were ascertained from FT-IR data. The morphology of hallow internal structural micro entities were confirmed by SEM. The optical properties were determined by DRS and PL spectra. Hence, the influence of the preparation methods on the structure, morphology and optical activities of bismuth vanadate was investigated systematically. Photocatalytic degradation (PCD) of Alizarin Red S (ARS), an effective disrupting chemical in aqueous medium was investigated using BiVO4 nanoparticles. The kinetics of PCD was found to follow pseudo first-order.

  1. Below and above boiling point comparison of microwave irradiation and conductive heating for municipal sludge digestion under identical heating/cooling profiles.

    PubMed

    Hosseini Koupaie, E; Eskicioglu, C

    2015-01-01

    This research provides a comprehensive comparison between microwave (MW) and conductive heating (CH) sludge pretreatments under identical heating/cooling profiles at below and above boiling point temperatures. Previous comparison studies were constrained to an uncontrolled or a single heating rate due to lack of a CH equipment simulating MW under identical thermal profiles. In this research, a novel custom-built pressure-sealed vessel which could simulate MW pretreatment under identical heating/cooling profiles was used for CH pretreatment. No statistically significant difference was proven between MW and CH pretreatments in terms of sludge solubilization, anaerobic biogas yield and organics biodegradation rate (p-value>0.05), while statistically significant effects of temperature and heating rate were observed (p-value<0.05). These results explain the contradictory results of previous studies in which only the final temperature (not heating/cooling rates) was controlled. PMID:25863200

  2. Microwave system performance summary

    NASA Technical Reports Server (NTRS)

    Arndt, G. D.; Nalos, E. J.

    1980-01-01

    The design of the microwave system for the solar power satellite is described. Design modifications recommended include changes in phase control to the power module level, a reduction in allowable amplitude jitter, the use of metal matrix waveguides, and sequences for startup/shutdown procedures. Investigations into reshaping the beam pattern to improve overall rectenna collection efficiency and improve sidelobe control are surveyed.

  3. Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Engineering Test Report: AMSU-A2 METSAT Instrument (S/N 108) Acceptance Level Vibration Tests of Dec 1999/Jan 2000 (S/O 784077, OC-454)

    NASA Technical Reports Server (NTRS)

    Heffner, R.

    2000-01-01

    This is the Engineering Test Report, AMSU-A2 METSAT Instrument (S/N 108) Acceptance Level Vibration Test of Dec 1999/Jan 2000 (S/O 784077, OC-454), for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A).

  4. Pulse duration determines levels of Hsp70 induction in tissues following laser irradiation

    NASA Astrophysics Data System (ADS)

    Mackanos, Mark A.; Contag, Christopher H.

    2011-07-01

    Induction of heat shock protein (Hsp) expression correlates with cytoprotection, reduced tissue damage, and accelerated healing in animal models. Since Hsps are transcriptionally activated in response to stress, they can act as stress indicators in burn injury or surgical procedures that produce heat and thermal change. A fast in vivo readout for induction of Hsp transcription in tissues would allow for the study of these proteins as therapeutic effect mediators and reporters of thermal stress/damage. We used a transgenic reporter mouse in which a luciferase expression is controlled by the regulatory region of the inducible 70 kilodalton (kDa) Hsp as a rapid readout of cellular responses to laser-mediated thermal stress/injury in mouse skin. We assessed the pulse duration dependence of the Hsp70 expression after irradiation with a CO2 laser at 10.6 μm in wavelength over a range of 1000 to 1 ms. Hsp70 induction varied with changes in laser pulse durations and radiant exposures, which defined the ranges at which thermal activation of Hsp70 can be used to protect cells from subsequent stress, and reveals the window of thermal stress that tissues can endure.

  5. Chemical decomposition of high-level nuclear waste storage/disposal glasses under irradiation. 1997 annual progress report

    SciTech Connect

    Griscom, D.L.; Merzbacher, C.I.

    1997-01-01

    'The objective of this research is to use the sensitive technique of electron spin resonance (ESR) to look for evidence of radiation-induced chemical decomposition of vitreous forms contemplated for immobilization of plutonium and/or high-level nuclear wastes, to interpret this evidence in terms of existing knowledge of glass structure, and to recommend certain materials for further study by other techniques, particularly electron microscopy and measurements of gas evolution by high-vacuum mass spectroscopy. Previous ESR studies had demonstrated that an effect of y rays on a simple binary potassium silicate glass was to induce superoxide (O{sub 2}{sup -}) and ozonide (O{sub 3}{sup -}) as relatively stable product of long-term irradiation Accordingly, some of the first experiments performed as a part of the present effort involved repeating this work. A glass of composition 44 K{sub 2}O: 56 SiO{sub 2} was prepared from reagent grade K{sub 2}CO3 and SiO{sub 2} powders melted in a Pt crucible in air at 1,200 C for 1.5 hr. A sample irradiated to a dose of 1 MGy (1 MGy = 10{sup 8} rad) indeed yielded the same ESR results as before. To test the notion that the complex oxygen ions detected may be harbingers of radiation-induced phase separation or bubble formation, a small-angle neutron scattering (SANS) experiment was performed. SANS is theoretically capable of detecting voids or bubbles as small as 10 \\305 in diameter. A preliminary experiment was carried out with the collaboration of Dr. John Barker (NIST). The SANS spectra for the irradiated and unirradiated samples were indistiguishable. A relatively high incoherent background (probably due to the presence of protons) may obscure scattering from small gas bubbles and therefore decrease the effective resolution of this technique. No further SANS experiments are planned at this time.'

  6. Effect of low-level laser irradiation on proliferation and viability of human dental pulp stem cells.

    PubMed

    Zaccara, Ivana Maria; Ginani, Fernanda; Mota-Filho, Haroldo Gurgel; Henriques, Águida Cristina Gomes; Barboza, Carlos Augusto Galvão

    2015-12-01

    A positive effect of low-level laser irradiation (LLLI) on the proliferation of some cell types has been observed, but little is known about its effect on dental pulp stem cells (DPSCs). The aim of this study was to identify the lowest energy density able to promote the proliferation of DPSCs and to maintain cell viability. Human DPSCs were isolated from two healthy third molars. In the third passage, the cells were irradiated or not (control) with an InGaAlP diode laser at 0 and 48 h using two different energy densities (0.5 and 1.0 J/cm²). Cell proliferation and viability and mitochondrial activity were evaluated at intervals of 24, 48, 72, and 96 h after the first laser application. Apoptosis- and cell cycle-related events were analyzed by flow cytometry. The group irradiated with an energy density of 1.0 J/cm² exhibited an increase of cell proliferation, with a statistically significant difference (p < 0.05) compared to the control group at 72 and 96 h. No significant changes in cell viability were observed throughout the experiment. The distribution of cells in the cell cycle phases was consistent with proliferating cells in all three groups. We concluded that LLLI, particularly a dose of 1.0 J/cm², contributed to the growth of DPSCs and maintenance of its viability. This fact indicates this therapy to be an important future tool for tissue engineering and regenerative medicine involving stem cells. PMID:26341379

  7. [Effect of microwaves on the vegetative and spore forms of Bacillus stearothermophilus].

    PubMed

    Salvatorelli, G; Rosaspina, S; Sartea, A; Anzanel, D

    1993-02-01

    Microwave irradiation provides a rapid and effective method for sterilization of stainless steel scalpel blades or cover glasses contaminated by B. stearothermophilus. A study by SEM of vegetative forms showed that microwave irradiation induce a progressive series of alterations and finally the complete destruction of the microorganism. On the contrary there were no significant morphological variations of the spores after lethal irradiation by microwaves. PMID:8129884

  8. Atomic force microscopy investigation of the interaction of low-level laser irradiation of collagen thin films in correlation with fibroblast response.

    PubMed

    Stylianou, Andreas; Yova, Dido

    2015-12-01

    Low-level red laser (LLRL)-tissue interactions have a wide range of medical applications and are garnering increased attention. Although the positive effects of low-level laser therapy (LLLT) have frequently been reported and enhanced collagen accumulation has been identified as one of the most important mechanisms involved, little is known about LLRL-collagen interactions. In this study, we aimed to investigate the influence of LLRL irradiation on collagen, in correlation with fibroblast response. Atomic force microscopy (AFM) and fluorescence spectroscopy were used to characterize surfaces and identify conformational changes in collagen before and after LLRL irradiation. Irradiated and non-irradiated collagen thin films were used as culturing substrates to investigate fibroblast response with fluorescence microscopy. The results demonstrated that LLRL induced small alterations in fluorescence emission and had a negligible effect on the topography of collagen thin films. However, fibroblasts cultured on LLRL-irradiated collagen thin films responded to LRLL. The results of this study show for the first time the effect of LLRL irradiation on pure collagen. Although irradiation did not affect the nanotopography of collagen, it influenced cell behavior. The role of collagen appears to be crucial in the LLLT mechanism, and our results demonstrated that LLRL directly affects collagen and indirectly affects cell behavior. PMID:26498450

  9. Irradiation-level and late effects among personnel working at {open_quotes}Mayak{close_quotes} during first years of exploitation

    SciTech Connect

    Nikipelov, B.V.; Lyzlov, A.F.; Koshurnikova, N.A.

    1993-12-31

    This research contains the information about the irradiation and late effects among the personnel of the first atomic power industry enterprise in this country. This research includes the characteristic of working standards, especially in radioactive dangerous departments. The research contains data on the organization of dosimetrical control and measures on normalizing the radioactive conditions. The research presents the information about the external {gamma}-irradiation levels among different groups of the personnel; the analysis of late effects, depending upon doses of external {gamma}-irradiation, which were essentially higher than the norm during the first years of the exploitation of the plant.

  10. Microwave furnace having microwave compatible dilatometer

    DOEpatents

    Kimrey, Jr., Harold D.; Janney, Mark A.; Ferber, Mattison K.

    1992-01-01

    An apparatus for measuring and monitoring a change in the dimension of a sample being heated by microwave energy is described. The apparatus comprises a microwave heating device for heating a sample by microwave energy, a microwave compatible dilatometer for measuring and monitoring a change in the dimension of the sample being heated by microwave energy without leaking microwaves out of the microwave heating device, and a temperature determination device for measuring and monitoring the temperature of the sample being heated by microwave energy.

  11. Microwave furnace having microwave compatible dilatometer

    DOEpatents

    Kimrey, H.D. Jr.; Janney, M.A.; Ferber, M.K.

    1992-03-24

    An apparatus for measuring and monitoring a change in the dimension of a sample being heated by microwave energy is described. The apparatus comprises a microwave heating device for heating a sample by microwave energy, a microwave compatible dilatometer for measuring and monitoring a change in the dimension of the sample being heated by microwave energy without leaking microwaves out of the microwave heating device, and a temperature determination device for measuring and monitoring the temperature of the sample being heated by microwave energy. 2 figs.

  12. CHEMICAL DECOMPOSITION OF HIGH-LEVEL NUCLEAR WASTE STORAGE/DISPOSAL GLASSES UNDER IRRADIATION

    EPA Science Inventory

    The Offices of Energy Research and Environmental Management are immediately concerned with the development of storage/immobilization media for high-level nuclear wastes and excess weapons plutonium. These media must be stable and free of risk to the public or to the environment f...

  13. Irradiation with a low-level diode laser induces the developmental endothelial locus-1 gene and reduces proinflammatory cytokines in epithelial cells.

    PubMed

    Fujimura, Takeki; Mitani, Akio; Fukuda, Mitsuo; Mogi, Makio; Osawa, Kazuhiro; Takahashi, Shinko; Aino, Makoto; Iwamura, Yuki; Miyajima, Shinichi; Yamamoto, Hiromitsu; Noguchi, Toshihide

    2014-05-01

    We demonstrated previously that low-level diode laser irradiation with an indocyanine green-loaded nanosphere coated with chitosan (ICG-Nano/c) had an antimicrobial effect, and thus could be used for periodontal antimicrobial photodynamic therapy (aPDT). Since little is known about the effects of aPDT on periodontal tissue, we here investigated the effect of low-level laser irradiation, with and without ICG-Nano/c, on cultured epithelial cells. Human oral epithelial cells were irradiated in a repeated pulse mode (duty cycle, 10 %; pulse width, 100 ms; peak power output, 5 W). The expression of the developmental endothelial locus 1 (Del-1), interleukin-6 (IL-6), IL-8, and the intercellular adhesion molecule-1 (ICAM-1) were evaluated in Ca9-22 cells stimulated by laser irradiation and Escherichia coli-derived lipopolysaccharide (LPS). A wound healing assay was carried out on SCC-25 cells irradiated by diode laser with or without ICG-Nano/c. The mRNA expression of Del-1, which is known to have anti-inflammatory activity, was significantly upregulated by laser irradiation (p < 0.01). Concurrently, LPS-induced IL-6 and IL-8 expression was significantly suppressed in the LPS + laser group (p < 0.01). ICAM-1 expression was significantly higher in the LPS + laser group than in the LPS only or control groups. Finally, compared with the control, the migration of epithelial cells was significantly increased by diode laser irradiation with or without ICG-Nano/c. These results suggest that, in addition to its antimicrobial effect, low-level diode laser irradiation, with or without ICG-Nano/c, can suppress excessive inflammatory responses via a mechanism involving Del-1, and assists in wound healing. PMID:24197516

  14. Study on the synthesis and formation mechanism of Cu{sub 2}ZnSnS{sub 4} particles by microwave irradiation

    SciTech Connect

    Wang, Wei; Shen, Honglie He, Xiancong

    2013-09-01

    Graphical abstract: - Highlights: • Cu{sub 2}ZnSnS{sub 4} microparticles were fabricated by low-cost chemical method. • The ball cactus-like shaped microparticles are with a diameter about 250 nm. • The optical band energy of Cu{sub 2}ZnSnS{sub 4} microparticles is obtained to be about 1.5 eV. • The CuS nuclei firstly form, and serve as the growth point for Cu{sub 2}ZnSnS{sub 4}. - Abstract: Cu{sub 2}ZnSnS{sub 4} (CZTS) particles were successfully synthesized by microwave assisted solvothermal method. The structure, shape, composition, and optical properties of these particles were investigated with X-ray diffraction, Raman spectroscopy, scanning electron microscopy, energy dispersive spectrometer, and UV–vis-NIR spectroscopy. The results show that the as-prepared particles had single phase, stoichiometric composition, and a ball cactus-like shape with a diameter about 250 nm, when reaction time is 10 min. The formation mechanism of the CZTS particles was investigated by evaluation of samples prepared with different reaction time. According to the proposed growth mechanism of CZTS particles, the copper sulfide nuclei firstly forms, and serves as the starting point for the nucleation and growth of CZTS.

  15. Degradation of Amaranth azo dye in water by heterogeneous photo-Fenton process using FeWO4 catalyst prepared by microwave irradiation.

    PubMed

    da Cruz Severo, Eric; Anchieta, Chayene Gonçalves; Foletto, Vitória Segabinazzi; Kuhn, Raquel Cristine; Collazzo, Gabriela Carvalho; Mazutti, Marcio Antonio; Foletto, Edson Luiz

    2016-01-01

    FeWO4 particles were synthesized by a simple, rapid and facile microwave technique and their catalytic properties in heterogeneous photo-Fenton reaction were evaluated. This material was employed in the degradation of Amaranth azo dye. Individual and interactive effects of operational parameters such as pH, dye concentration and H2O2 dosage on the decolorization efficiency of Amaranth dye were evaluated by 2(3) central composite design. According to characterization techniques, a porous material and a well-crystallized phase of FeWO4 oxide were obtained. Regarding the photo-Fenton reaction assays, up to 97% color and 58% organic carbon removal were achieved in the best experimental conditions. In addition, the photo-Fenton process maintained treatment efficiency over five catalyst reuse cycles to indicate the durability of the FeWO4 catalyst. In summary, the results reveal that the synthesized FeWO4 material is a promising catalyst for wastewater treatment by heterogeneous photo-Fenton process. PMID:26744938

  16. Microwave-assisted FLP-catalyzed hydrogenations.

    PubMed

    Tussing, S; Paradies, J

    2016-03-30

    FLP-catalyzed hydrogenations of 15 substrates were compared using microwave irradiation and conventional heating. The direct comparison revealed that a rate acceleration of up to 2.5 was achieved in the presence of microwaves. This heating method is particularly promising for the hydrogenation of nitrogen-containing heterocycles. Acridine, quinines and especially 1-methyl indole were reduced very efficiently under mild conditions and only 4 bar hydrogen pressure in high yields. PMID:26580129

  17. Hair Mercury Levels Detection in Fishermen from Sicily (Italy) by ICP-MS Method after Microwave-Assisted Digestion

    PubMed Central

    Giangrosso, Giuseppe; Cammilleri, Gaetano; Macaluso, Andrea; Vella, Antonio; D'Orazio, Nicolantonio; Graci, Stefania; Lo Dico, Gianluigi Maria; Galvano, Fabio; Giangrosso, Margherita; Ferrantelli, Vincenzo

    2016-01-01

    A number of ninety-six hair samples from Sicilian fishermen were examined for total mercury detection by an Inductively Coupled Plasma Mass Spectrometry (ICP-MS) method. The mercury levels obtained were compared with mercury levels of 96 hair samples from a control group, in order to assess potential exposure to heavy metals of Sicilian fishermen due to fish consumption and closeness to industrial activities. Furthermore, the mercury levels obtained from hair samples were sorted by sampling area in order to verify the possible risks linked to the different locations. The overall mean concentration in the hair of the population of fishermen was 6.45 ± 7.03 μg g−1, with a highest value in a fisherman of Sciacca (16.48 μg g−1). Hair mercury concentration in fishermen group was significantly higher than in control group (p < 0.01). There was no significant difference in hair total mercury concentrations between sampling areas (p > 0.05). The results of this study indicate a greater risk of exposure to mercury in Sicilian fishermen, in comparison to the control population, due to the high consumption of fish and the close relationship with sources of exposure (ports, dumps, etc.). PMID:27127456

  18. Synthesis of Ag@TiO2 core-shells using a rapid microwave irradiation and study of their nonlinear optical properties

    NASA Astrophysics Data System (ADS)

    Karimipour, M.; Ebrahimi, M.; Abafat, Z.; Molaei, M.

    2016-07-01

    Ag@TiO2 core-shells were synthesized by employing oleylamine as capping agent and using a rapid microwave method. The shell growth was optimized first based on the variation of oleylamine content in the reaction solution. Thereafter the shell thickness was varied just by varying titanium isopropoxide (TiTP) with 25, 50, 100 and 200 μl as TiO2 precursor. The prepared core-shells were characterized by means of XRD, FTIR spectroscopy, transmission electron microscopy, and UV-Vis spectroscopy. XRD analysis revealed a cubic crystal structure for Ag and Anatase phase for TiO2. TEM images clearly indicated that the size of Ag core is roughly 15 nm and with the increase of TiTP, the shell thickness increases and varies between 5 nm and 15 nm. UV-Vis spectroscopy indicated that the plasmon resonance of Ag nanoparticles shifts from 407 nm up to 454 nm with the increase of TiTP precursor. Using a low power laser diode at a 532 nm wavelength, the magnitude and the sign of the nonlinear refractive index were determined by the Z-scan technique and Sheik-Bahae model. The results show that the enhancement of nonlinear optical properties originates from the quality of TiO2 shell growth. The highest nonlinearity belongs to the sample synthesized with 100 μlit TiTP. Generally all the prepared Ag@TiO2 core-shells show both saturable and reverse saturable absorption. They exhibit also a considerable nonlinear absorption and nonlinear refractive index ranging from -4.21 × 10-7 to -3.51 × 10-6 which are comparable to the sole Ag and TiO2 nanoparticles.

  19. Method for digesting spent ion exchange resins and recovering actinides therefrom using microwave radiation

    DOEpatents

    Maxwell, III, Sherrod L.; Nichols, Sheldon T.

    1999-01-01

    The present invention relates to methods for digesting diphosphonic acid substituted cation exchange resins that have become loaded with actinides, rare earth metals, or heavy metals, in a way that allows for downstream chromatographic analysis of the adsorbed species without damage to or inadequate elution from the downstream chromatographic resins. The methods of the present invention involve contacting the loaded diphosphonic acid resin with concentrated oxidizing acid in a closed vessel, and irradiating this mixture with microwave radiation. This efficiently increases the temperature of the mixture to a level suitable for digestion of the resin without the use of dehydrating acids that can damage downstream analytical resins. In order to ensure more complete digestion, the irradiated mixture can be mixed with hydrogen peroxide or other oxidant, and reirradiated with microwave radiation.

  20. Apparatus and method for microwave processing of materials using field-perturbing tool

    DOEpatents

    Tucker, Denise A.; Fathi, Zakaryae; Lauf, Robert J.

    2001-01-01

    A variable frequency microwave heating apparatus designed to allow modulation of the frequency of the microwaves introduced into a multi-mode microwave cavity for heating or other selected applications. A field-perturbing tool is disposed within the cavity to perturb the microwave power distribution in order to apply a desired level of microwave power to the workpiece.

  1. Studies on the storage life of irradiated potatoes of different maturities as influenced by different levels of nitrogen during growth and different harvest dates

    SciTech Connect

    Badshah, N.L.

    1989-01-01

    Studies were conducted to determine the effects of irradiation levels on potato tubers of different maturities grown with 0.0, 182 and 364 kg/ha nitrogen in 16-16-16 NPK fertilizer, harvested on different dates and stored at 10 and 15.5{degree}C. Tubers from the 1986 crop were harvested on September 15, 1986. Tubers from the 1987 crop were harvested when 0-5%, 50%, and 100% of the vines had died. Gamma irradiation was applied to the tubers of the 1986 crop at dosage 0, 5, 10 and 20 krad; and 0 and 7.5 krad for the tubers of 1987 crop. The 1986 study indicated that increasing fertilizer and irradiation levels significantly decreased sprouting, percent weight loss and specific gravity of tubers. The loss of ascorbic acid, histidine, leucine, isoleucine, and the amount of reducing, and non-reducing sugars were significantly decreased by increasing nitrogen levels. The content of leucine, reducing sugars and ascorbic acid levels were decreased by irradiation. Higher storage temperatures caused greater loss of arginine, isoleucine, valine and ascorbic acid. No significant changes were found in protein, lysine and aromatic amino acids. Tubers stored at 15.5{degree}C showed greater metabolic changes as indicated by sprouting, weight loss; changes in permeability, protein, amino acids, sugars and ascorbic acid contents. The 5 krad irradiation treatment resulted in complete sprout inhibition of tubers from 364 kg/ha nitrogen levels at 10{degree}C storage. Twenty krad dosage while inhibiting sprouting at 15.5{degree}C, caused greater loss of ascorbic acid. The results of 1987 studies showed that tubers from higher nitrogen levels irradiated with 7.5 krad significantly decreased weight loss.

  2. Polymeric flocculants processing by accelerated electron beams and microwave heating

    NASA Astrophysics Data System (ADS)

    Martin, Diana I.; Mateescu, Elena; Craciun, Gabriela; Ighigeanu, Daniel; Ighigeanu, Adelina

    2002-08-01

    Results obtained by accelerated electron beam, microwave and simultaneous microwave and electron beam application in the chemistry of acrylamide and acrylic acid copolymers (polymeric flocculants used for wastewater treatment) are presented. Comparative results concerning the molecular weight and Huggins' constant for the acrylamide and acrylic acid copolymers obtained by classical heating, microwave heating, electron beam irradiation and simultaneous microwave and electron beam treatment are reported. Microwave heating produces high water solubility of the polymeric flocculants but median molecular weight values. Electron beam irradiation gives high molecular weight values but associated with a cross-linked structure (poor water solubility) while microwave energy addition to electron beam energy gives simultaneously high molecular weight values and high water solubility.

  3. I. Microwave Apparatus for Exposing Tissue and the Effect of the Radiation on Skin Respiration

    PubMed Central

    Lawrence, J. C.

    1968-01-01

    An apparatus was designed which enabled small pieces of skin to be exposed to a uniform field of microwaves at χ-band (8,730 MHz). This was used to investigate the effect of these microwaves at selected energy levels on the metabolism of skin. It was shown that skin cultured in vitro exhibited a graded response to microwave energy, and a doseresponse curve was constructed from this data. The ED50 of this curve was 4,740 mW./sq. cm. applied for 1 second. Microscopical examination of three-day cultures of skin showed that histological abnormalities occurred if the specimens were exposed to intensities of microwaves causing more than 30% respiratory damage. The energy level at the ED30 was 2,880 mW./sq. cm. applied for 1 second. Results were consistent with the hypothesis that tissue damage caused by irradiation with microwaves was due to the energy absorbed by the specimen being converted to heat. PMID:5663427

  4. Effect of low-level laser therapy on irradiated parotid glands—study in mice

    NASA Astrophysics Data System (ADS)

    Acauan, Monique Dossena; Gomes, Ana Paula Neutziling; Braga-Filho, Aroldo; de Figueiredo, Maria Antonia Zancanaro; Cherubini, Karen; Salum, Fernanda Gonçalves

    2015-10-01

    The objective of this study was to evaluate the effect of low-level laser therapy (LLLT) on radiotherapy-induced morphological changes and caspase-3 immunodetection in parotids of mice. Forty-one Swiss mice were divided into control, radiotherapy, 2- and 4-J laser groups. The experimental groups were exposed to ionizing radiation in a single session of 10 Gy. In the laser groups, a GaAlAs laser (830 nm, 100 mW, 0.028 cm2, 3.57 W/cm2) was used on the region corresponding to the parotid glands, with 2-J energy (20 s, 71 J/cm2) or 4 J (40 s, 135 J/cm2) per point. LLLT was performed immediately before and 24 h after radiotherapy. One point was applied in each parotid gland. The animals were euthanized 48 h or 7 days after radiotherapy and parotid glands were dissected for morphological analysis and immunodetection of caspase-3. There was no significant difference between groups in the immunodetection of caspase-3, but the laser groups had a lower percentage compared to the radiotherapy group. LLLT promoted the preservation of acinar structure, reduced the occurrence of vacuolation, and stimulated parotid gland vascularization. Of the two LLLT protocols, the one using 4 J of energy showed better results.

  5. A reusable robust radio frequency biosensor using microwave resonator by integrated passive device technology for quantitative detection of glucose level.

    PubMed

    Kim, N Y; Dhakal, R; Adhikari, K K; Kim, E S; Wang, C

    2015-05-15

    A reusable robust radio frequency (RF) biosensor with a rectangular meandered line (RML) resonator on a gallium arsenide substrate by integrated passive device (IPD) technology was designed, fabricated and tested to enable the real-time identification of the glucose level in human serum. The air-bridge structure fabricated by an IPD technology was applied to the RML resonator to improve its sensitivity by increasing the magnitude of the return loss (S21). The resonance behaviour, based on S21 characteristics of the biosensor, was analysed at 9.20 GHz with human serum containing different glucose concentration ranging from 148-268 mg dl(-1), 105-225 mg dl(-1) and at a deionised (D) water glucose concentration in the range of 25- 500 mg dl(-1) for seven different samples. A calibration analysis was performed for the human serum from two different subjects and for D-glucose at a response time of 60 s; the reproducibility, the minimum shift in resonance frequency and the long-term stability of the signal were investigated. The feature characteristics based on the resonance concept after the use of serum as an analyte are modelled as an inductor, capacitor and resistor. The findings support the development of resonance-based sensing with an excellent sensitivity of 1.08 MHz per 1 mg dl(-1), a detection limit of 8.01 mg dl(-1), and a limit of quantisation of 24.30 mg dl(-1). PMID:25459060

  6. DIRECT SYNTHESIS OF TERTIARY AMINES IN WATER USING MICROWAVES

    EPA Science Inventory

    A direct synthesis of tertiary amines is presented that proceeds expeditiously via N-alkylation of amines using alkyl halides in alkaline aqueous medium. This environmentally benign reaction is accelerated upon exposure to microwave irradiation resulting in shortened reaction tim...

  7. Microwave heating in peptide side chain modification via cysteine alkylation.

    PubMed

    Calce, Enrica; De Luca, Stefania

    2016-09-01

    Microwave irradiation has been successfully applied to a selective synthetic procedure for introducing molecular substituents on peptides, providing a noticeable reduction of the reaction time and also an increased crude peptide purity for some compounds. PMID:27351201

  8. The radial transmission line as a broad-band shielded exposure system for microwave irradiation of large numbers of culture flasks.

    PubMed

    Moros, E G; Straube, W L; Pickard, W F

    1999-01-01

    The problem of simultaneously exposing large numbers of culture flasks at nominally equivalent incident power densities and with good thermal control is considered, and the radial transmission line (RTL) is proposed as a solution. The electromagnetic design of this structure is discussed, and an extensively bench-tested realization is described. Referred to 1 W of net forward power, the following specific absorption rate (SAR) data were obtained: at 835.62 MHz, 16.0+/-2.5 mW/kg (mean+/-SD) with range (11-22); at 2450 MHz, 245+/-50 mW/kg with range (130-323). Radio-frequency interference from an RTL driven at roughly 100 W is so low as to be compatible with a cellular base station only 500 m distant. To avoid potential confounding by temperature differences among as many as 144 T-75 flasks distributed over 9 RTLs (six irradiates and three shams), temperature within all flasks was controlled to 37.0+/-0.3 degrees C. Experience with over two years of trouble-free operation suggests that the RTL offers a robust, logistically friendly, and environmentally satisfactory solution to the problem of large-scale in vitro experiments in bioelectromagnetics. PMID:10029133

  9. ENVIRONMENTALLY FRIENDLIER ALTERNATIVES TO ORGANIC SYNTHESIS USING MICROWAVES

    EPA Science Inventory

    Microwave irradiation has been used for a variety of organic transformations wherein chemical reactions are expedited because of selective adsorption of microwave (MW) energy by polar molecules, non-polar molecules being inert to the MW dielectric loss. The MW application under s...

  10. HYDRODECHLORINATION OF CHLORINATED BENZENES IN A CONTINUOUS MICROWAVE REACTOR

    EPA Science Inventory

    An expeditious hydrodechlorination of chlorobenzenes is observed over 0.5% Pd/Al2O3 catalyst by conducting the reaction under microwave irradiation conditions. Even though the loss of active metal surface area is substantial and identical in both microwave ...

  11. GREENER APPROACH TO EFFICIENT ORGANIC SYNTHESES USING MICROWAVES

    EPA Science Inventory

    Microwave irradiation has been used for a variety of organic transformations wherein chemical reactions are expedited because of selective adsorption of microwave (MW) energy by polar molecules, non-polar molecules being inert to the MW dielectric loss. The MW application under s...

  12. Microwave-Induced Chemotoxicity of Polydopamine-Coated Magnetic Nanocubes

    PubMed Central

    Julfakyan, Khachatur; Fatieiev, Yevhen; Alsaiari, Shahad; Deng, Lin; Ezzeddine, Alaa; Zhang, Dingyuan; Rotello, Vincent M.; Khashab, Niveen M.

    2015-01-01

    Polydopamine-coated FeCo nanocubes (PDFCs) were successfully synthesized and tested under microwave irradiation of 2.45 GHz frequency and 0.86 W/cm2 power. These particles were found to be non-toxic in the absence of irradiation, but gained significant toxicity upon irradiation. Interestingly, no increase in relative heating rate was observed when the PDFCs were irradiated in solution, eliminating nanoparticle (NP)-induced thermal ablation as the source of toxicity. Based on these studies, we propose that microwave-induced redox processes generate the observed toxicity. PMID:26287162

  13. Study of federal microwave standards

    SciTech Connect

    David, L.

    1980-08-01

    Present and future federal regulatory processes which may impact the permissible levels of microwave radiation emitted by the SPS Microwave Power Transmission (MPTS) were studied. An historical development of US occupational and public microwave standards includes an overview of Western and East European philosophies of environmental protection and neurophysiology which have led to the current widely differing maximum permissible exposure limits to microwaves. The possible convergence of microwave standards is characterized by a lowering of Western exposure levels while Eastern countries consider standard relaxation. A trend toward stricter controls on activities perceived as harmful to public health is under way as is interest in improving the federal regulatory process. Particularly relevant to SPS is the initiation of long-term, low-level microwave exposure programs. Coupled with new developments in instrumentation and dosimetry, the results from chronic exposure program and population exposure studies could be expected within the next five to ten years. Also discussed is the increasing public concern that rf energy is yet another hazardous environmental agent.

  14. Microwave Induced Welding of Carbon Nanotube-Thermoplastic Interfaces for Enhanced Mechanical Strength of 3D Printed Parts

    NASA Astrophysics Data System (ADS)

    Sweeney, Charles; Lackey, Blake; Saed, Mohammad; Green, Micah

    Three-dimensional (3D) printed parts produced by fused-filament fabrication of a thermoplastic polymer have become increasingly popular at both the commercial and consumer level. The mechanical integrity of these rapid-prototyped parts however, is severely limited by the interfillament bond strength between adjacent extruded layers. In this report we propose for the first time a method for welding thermoplastic interfaces of 3D printed parts using the extreme heating response of carbon nanotubes (CNTs) to microwave energy. To achieve this, we developed a coaxial printer filament with a pure polylactide (PLA) core and a CNT composite sheath. This produces parts with a thin electrically percolating network of CNTs at the interfaces between adjacent extruded layers. These interfaces are then welded together upon microwave irradiation at 2.45GHz. Our patent-pending method has been shown to increase the tensile toughness by 1000% and tensile strength by 35%. We investigated the dielectric properties of the PLA/CNT composites at microwave frequencies and performed in-situ microwave thermometry using a forward-looking infrared (FLIR) camera to characterize the heating response of the PLA/CNT composites upon microwave irradiation.

  15. Chemical decomposition of high-level nuclear waste storage/disposal glasses under irradiation. 1998 annual progress report

    SciTech Connect

    Griscom, D.L.; Merzbacher, C.I.

    1998-06-01

    'The objective of this project is to employ the technique of electron spin resonance (ESR), in conjunction with other experimental methods, to study radiation-induced decomposition of vitreous compositions proposed for immobilization/disposal of high-level nuclear wastes (HLW) or excess weapons plutonium. ESR is capable of identifying, even at the parts-per-million level, displaced atoms, ruptured bonds, and free radicals created by radiation in such glassy forms. For example, one of the scientific goals is to determine whether ESR-detectable superoxide (O{sub 2}{sup -}) and ozonide (O{sub 3}{sup -}) ions are precursors of radiation-induced oxygen gas bubbles reported by other investigators. The fundamental understandings obtained in this study will enable reliable predictions of the long-term effects of and decays of the immobilized radionuclides on HLW glasses. This report represents the results of an 18-month effort performed under a 3-year research award. Four categories of materials were studied: (1) several actual and proposed HLW glass compositions fabricated at Savannah River Technology Center (SRTC), samples of which had been irradiated to a dose of 30 MGy (1 Gy = 100 rad) to simulate decay effects, (2) several high-iron phosphate glasses fabricated at the University of Missouri-Rolla (UMR), (3) one other model HLW glass and several simulated natural glasses which had been implanted with 160-keV He{sup +} ions to simulate-decay damage, and (4) an actual geological glass damaged by decays of trace amounts of contained {sup 238}U and {sup 232}Th over a period of 65 Myears. Among the category-1 materials were two samples of Defense Waste Processing Facility (DWPF) borosilicate glasses modeling compositions currently being used to vitrify HLW at SRTC. The ESR spectra recorded for the unirradiated DWPF-glass simulants were attributable to Fe 3{sup +} ions. The 30-MGy irradiation was found to change the Fe{sup 3+} concentration of these glasses by a

  16. High Levels of Dietary Supplement Vitamins A, C and E are Absorbed in the Small Intestine and Protect Nutrient Transport Against Chronic Gamma Irradiation.

    PubMed

    Roche, Marjolaine; Neti, Prasad V S V; Kemp, Francis W; Azzam, Edouard I; Ferraris, Ronaldo P; Howell, Roger W

    2015-11-01

    We examined nutrient transport in the intestines of mice exposed to chronic low-LET 137Cs gamma rays. The mice were whole-body irradiated for 3 days at dose rates of 0, 0.13 and 0.20 Gy/h, for total dose delivery of 0, 9.6 or 14.4 Gy, respectively. The mice were fed either a control diet or a diet supplemented with high levels of vitamins A, C and E. Our results showed that nutrient transport was perturbed by the chronic irradiation conditions. However, no apparent alteration of the macroscopic intestinal structures of the small intestine were observed up to day 10 after initiating irradiation. Jejunal fructose uptake measured in vitro was strongly affected by the chronic irradiation, whereas uptake of proline, carnosine and the bile acid taurocholate in the ileum was less affected. D-glucose transport did not appear to be inhibited significantly by either 9.6 or 14.4 Gy exposure. In the 14.4 Gy irradiated groups, the diet supplemented with high levels of vitamins A, C and E increased intestinal transport of fructose compared to the control diet (day 10; t test, P = 0.032), which correlated with elevated levels of vitamins A, C and E in the plasma and jejunal enterocytes. Our earlier studies with mice exposed acutely to 137Cs gamma rays demonstrated significant protection for transport of fructose, glucose, proline and carnosine. Taken together, these results suggest that high levels of vitamins A, C and E dietary supplements help preserve intestinal nutrient transport when intestines are irradiated chronically or acutely with low-LET gamma rays. PMID:26484399

  17. Radiation Tolerance of Aluminum Microwave Kinetic Inductance Detector

    NASA Astrophysics Data System (ADS)

    Karatsu, K.; Dominjon, A.; Fujino, T.; Funaki, T.; Hazumi, M.; Irie, F.; Ishino, H.; Kida, Y.; Matsumura, T.; Mizukami, K.; Naruse, M.; Nitta, T.; Noguchi, T.; Oka, N.; Sekiguchi, S.; Sekimoto, Y.; Sekine, M.; Shu, S.; Yamada, Y.; Yamashita, T.

    2016-08-01

    Microwave kinetic inductance detector (MKID) is one of the candidates of focal plane detector for future satellite missions such as LiteBIRD. For the space use of MKIDs, the radiation tolerance is one of the challenges to be characterized prior to the launch. Aluminum (Al) MKIDs with 50 nm thickness on silicon substrate and on sapphire substrate were irradiated with a proton beam of 160 MeV at the heavy ion medical accelerator in Chiba. The total water-equivalent absorbed dose was ˜ 10 krad which should simulate the worst radiation absorption of 5 years observation at the Lagrange point L2. We measured characteristics of these MKIDs before and after the irradiation. We found no significant changes on resonator quality factor, responsivity, and recombination time of quasi-particles. The change on electrical noise equivalent power was also evaluated, and no significant increase was found at the noise level of O(10^{-18}) W/√{ Hz }.

  18. Radiation Tolerance of Aluminum Microwave Kinetic Inductance Detector

    NASA Astrophysics Data System (ADS)

    Karatsu, K.; Dominjon, A.; Fujino, T.; Funaki, T.; Hazumi, M.; Irie, F.; Ishino, H.; Kida, Y.; Matsumura, T.; Mizukami, K.; Naruse, M.; Nitta, T.; Noguchi, T.; Oka, N.; Sekiguchi, S.; Sekimoto, Y.; Sekine, M.; Shu, S.; Yamada, Y.; Yamashita, T.

    2016-02-01

    Microwave kinetic inductance detector (MKID) is one of the candidates of focal plane detector for future satellite missions such as LiteBIRD. For the space use of MKIDs, the radiation tolerance is one of the challenges to be characterized prior to the launch. Aluminum (Al) MKIDs with 50 nm thickness on silicon substrate and on sapphire substrate were irradiated with a proton beam of 160 MeV at the heavy ion medical accelerator in Chiba. The total water-equivalent absorbed dose was ˜ 10 krad which should simulate the worst radiation absorption of 5 years observation at the Lagrange point L2. We measured characteristics of these MKIDs before and after the irradiation. We found no significant changes on resonator quality factor, responsivity, and recombination time of quasi-particles. The change on electrical noise equivalent power was also evaluated, and no significant increase was found at the noise level of O(10^{-18}) W/√{Hz}.

  19. Collaborational effect of heterolytic layered configuration for enhancement of microwave heating.

    PubMed

    Maitani, Masato M; Inoue, Tomoharu; Tsukushi, Yohei; Hansen, Niklas D J; Mochizuki, Dai; Suzuki, Eiichi; Wada, Yuji

    2013-11-28

    Microwave irradiation efficiently heats up the microwave-inert materials in the range of applied frequencies when two microwave-inert materials are brought into contact in the layered configuration. This heating is applied for annealing TiO2 nanoporous films for dye-sensitized solar cells achieving a one order of magnitude more rapid annealing process for comparable performances. PMID:24121483

  20. Comparison between the Strength Levels of Baseline Nuclear-Grade Graphite and Graphite Irradiated in AGC-2

    SciTech Connect

    Carroll, Mark Christopher

    2015-07-01

    This report details the initial comparison of mechanical strength properties between the cylindrical nuclear-grade graphite specimens irradiated in the second Advanced Graphite Creep (AGC-2) experiment with the established baseline, or unirradiated, mechanical properties compiled in the Baseline Graphite Characterization program. The overall comparative analysis will describe the development of an appropriate test protocol for irradiated specimens, the execution of the mechanical tests on the AGC-2 sample population, and will further discuss the data in terms of developing an accurate irradiated property distribution in the limited amount of irradiated data by leveraging the considerably larger property datasets being captured in the Baseline Graphite Characterization program. Integrating information on the inherent variability in nuclear-grade graphite with more complete datasets is one of the goals of the VHTR Graphite Materials program. Between “sister” specimens, or specimens with the same geometry machined from the same sub-block of graphite from which the irradiated AGC specimens were extracted, and the Baseline datasets, a comprehensive body of data will exist that can provide both a direct and indirect indication of the full irradiated property distributions that can be expected of irradiated nuclear-grade graphite while in service in a VHTR system. While the most critical data will remain the actual irradiated property measurements, expansion of this data into accurate distributions based on the inherent variability in graphite properties will be a crucial step in qualifying graphite for nuclear use as a structural material in a VHTR environment.

  1. Modulation of Extracellular ATP Content of Mast Cells and DRG Neurons by Irradiation: Studies on Underlying Mechanism of Low-Level-Laser Therapy

    PubMed Central

    Hu, Lei; Grygorczyk, Ryszard; Shen, Xueyong; Schwarz, Wolfgang

    2015-01-01

    Low-level-laser therapy (LLLT) is an effective complementary treatment, especially for anti-inflammation and wound healing in which dermis or mucus mast cells (MCs) are involved. In periphery, MCs crosstalk with neurons via purinergic signals and participate in various physiological and pathophysiological processes. Whether extracellular ATP, an important purine in purinergic signaling, of MCs and neurons could be modulated by irradiation remains unknown. In this study, effects of red-laser irradiation on extracellular ATP content of MCs and dorsal root ganglia (DRG) neurons were investigated and underlying mechanisms were explored in vitro. Our results show that irradiation led to elevation of extracellular ATP level in the human mast cell line HMC-1 in a dose-dependent manner, which was accompanied by elevation of intracellular ATP content, an indicator for ATP synthesis, together with [Ca2+]i elevation, a trigger signal for exocytotic ATP release. In contrast to MCs, irradiation attenuated the extracellular ATP content of neurons, which could be abolished by ARL 67156, a nonspecific ecto-ATPases inhibitor. Our results suggest that irradiation potentiates extracellular ATP of MCs by promoting ATP synthesis and release and attenuates extracellular ATP of neurons by upregulating ecto-ATPase activity. The opposite responses of these two cell types indicate complex mechanisms underlying LLLT. PMID:25691809

  2. Corticotropin-releasing factor antagonist blocks microwave-induced decreases in high-affinity choline uptake in the rat brain

    SciTech Connect

    Lai, H.; Carino, M.A.; Horita, A.; Guy, A.W. )

    1990-10-01

    Acute (45-min) irradiation with pulsed low-level microwaves (2450-MHz, 2 microseconds pulses at 500 pps, average power density of 1 mW/cm2, whole-body average specific absorption rate of 0.6 W/kg) decreased sodium-dependent high-affinity choline uptake (HACU) activity in the frontal cortex and hippocampus of the rat. These effects were blocked by pretreating the animals before exposure with intracerebroventricular injection of the specific corticotropin-releasing factor (CRF) receptor antagonist, alpha-helical-CRF9-41 (25 micrograms). Similar injection of the antagonist had no significant effect on HACU in the brain of the sham-exposed rats. These data suggest that low-level microwave irradiation activates CRF in the brain, which in turn causes the changes in central HACU.

  3. Microwave processing of ceramics

    SciTech Connect

    Katz, J.D.

    1989-01-01

    This paper discusses the following topics on microwave processing of ceramics: Microwave-material interactions; anticipated advantage of microwave sintering; ceramic sintering; and ceramic joining. 24 refs., 4 figs. (LSP)

  4. Cytokine production of the neutrophils and macrophages in time of phagocytosis under influence of infrared low-level laser irradiation

    NASA Astrophysics Data System (ADS)

    Rudik, Dmitry V.; Tikhomirova, Elena I.; Tuchina, Elena S.

    2006-08-01

    Influence of infrared low-level laser irradiation (LLLI) on induction of synthesis of some cytokines such as interleykin-1 (Il-1), tumor necrosis factor-α (TNF-α), interferon-γ (INF-γ), interleykin-8 (Il-8) and interleykin-4 (Il-4) by the neutrophils and macrophages in time of bacterial cells phagocytosis that was searched. As the object of analysis we used peritoneal macrophages from white mice and neutrophils from peripheral blood of healthy donors. We used the laser diod with spectrum maximum of 850 nm with doses 300, 900 and 1500 mJ (exposition -60, 180 and 300 s respectively; capacity - 5 mW). We carried out the Enzyme-Linked Immunospot Assay (ELISA) to determine cytokine content during phagocytosis after 3 h and 6 h. We found dynamics in production of the cytokines, which was different for the neutrophils and macrophages. We showed that the infrared LLLI has significant stimulating activity on the proinflammatory cytokines production by neutrophils and macrophages. Moreover we revealed dynamics changing in the Il-8 and Il-4 production.

  5. Induction of ploidy level increments in an asporogenous industrial strain of the yeast Saccharomyces cerevisiae by UV irradiation.

    PubMed Central

    Sasaki, T

    1992-01-01

    Cells of an asporogenous industrial strain of the yeast Saccharomyces cerevisiae were irradiated with UV light by using a method that was developed previously (T. Sasaki and Y. Ohshima, Appl. Environ. Microbiol. 53:1504-1511, 1987). This treatment gave rise to large-cell clones among the surviving cells, from which colonies consisting of cells with a normal morphology and a prototrophic property were obtained. The large-cell trait of these was stably inheritable, with the cell volumes being about twice that of the parent for 7 years on a slant agar medium at 4 degrees C with repeated transfers. The cellular DNA content of these clones, in comparison to those of two authentic haploid strains, was determined by chemical analysis. The ratio of the DNA contents showed that the parent and its large-cell derivatives were a diploid and tetraploids, respectively. No abnormality was found in the chromosomal DNA patterns of the large-cell clones, at least as determined by agarose gel electrophoresis with a CHEF-DR II pulsed-field electrophoresis system. These findings led to the conclusion that our UV light method is applicable for inducing ploidy level increments in the widely used yeast species S. cerevisiae. Images PMID:1575498

  6. The effect of low-level laser irradiation on muscle tension and hardness compared among three wavelengths

    PubMed Central

    Kogure, Shinichi

    2013-01-01

    Background and Aims: It has been reported that low-level laser irradiation (LLLI) can influence muscle tissue by retarding attenuation of muscle tension. Since the efficacy of LLLI on the effects of muscle contraction remains unclear, we examined in an in vivo animal model whether LLLI affects both muscle tension and muscle hardness in a wavelength-dependent manner, using the rat gastrocnemius muscle. Material and Methods: Forty Sprague-Dawley adult rats were used. Under pentobarbital sodium anesthesia, their gastrocnemius muscle and tibial nerve were exteriorized. Diode LLLI systems delivering 3 wavelengths (405, 532, and 808 nm; 100 mW output) were used. Ten sets of tetanus (tetanic contractions) were delivered to the tibial nerve followed by a brief rest or LLLI for 15 s and an additional 7 sets of tetanus with an inter-stimulus interval of 5 min. The muscle tension and muscle hardness were measured with a tension transducer and hardness meter, respectively. Results: 405 nm LLLI did not influence either muscle tension or hardness. 532 nm LLLI significantly improved the maintenance of muscle tension compared with the 808 nm group (P<0.05). In contrast, 808 nm LLLI significantly improved the recovery from muscle hardness compared with the other groups (P<0.05). Conclusion: We conclude that LLLI has wavelength-dependent effects on the gastrocnemius muscle and LLLI at appropriate wavelengths and dosimetry offers potential in the treatment to relieve muscle tension or stiffness. PMID:24204094

  7. The Contribution of Tissue Level Organization to Genomic Stability Following Low Dose/Low Dose Rate Gamma and Proton Irradiation

    SciTech Connect

    Cheryl G. Burrell, Ph.D.

    2012-05-14

    The formation of functional tissue units is necessary in maintaining homeostasis within living systems, with individual cells contributing to these functional units through their three-dimensional organization with integrin and adhesion proteins to form a complex extra-cellular matrix (ECM). This is of particular importance in those tissues susceptible to radiation-induced tumor formation, such as epithelial glands. The assembly of epithelial cells of the thyroid is critical to their normal receipt of, and response to, incoming signals. Traditional tissue culture and live animals present significant challenges to radiation exposure and continuous sampling, however, the production of bioreactor-engineered tissues aims to bridge this gap by improve capabilities in continuous sampling from the same functional tissue, thereby increasing the ability to extrapolate changes induced by radiation to animals and humans in vivo. Our study proposes that the level of tissue organization will affect the induction and persistence of low dose radiation-induced genomic instability. Rat thyroid cells, grown in vitro as 3D tissue analogs in bioreactors and as 2D flask grown cultures were exposed to acute low dose (1, 5, 10 and 200 cGy) gamma rays. To assess immediate (6 hours) and delayed (up to 30 days) responses post-irradiation, various biological endpoints were studied including cytogenetic analyses, apoptosis analysis and cell viability/cytotoxicity analyses. Data assessing caspase 3/7 activity levels show that, this activity varies with time post radiation and that, overall, 3D cultures display more genomic instability (as shown by the lower levels of apoptosis over time) when compared to the 2D cultures. Variation in cell viability levels were only observed at the intermediate and late time points post radiation. Extensive analysis of chromosomal aberrations will give further insight on the whether the level of tissue organization influences genomic instability patterns after

  8. Connecting forest ecosystem and microwave backscatter models

    NASA Technical Reports Server (NTRS)

    Kasischke, Eric S.; Christensen, Norman L., Jr.

    1990-01-01

    A procedure is outlined to connect data obtained from active microwave remote sensing systems with forest ecosystem models. The hierarchy of forest ecosystem models is discussed, and the levels at which microwave remote sensing data can be used as inputs are identified. In addition, techniques to utilize forest ecosystem models to assist in the validation of theoretical microwave backscatter models are identified. Several examples to illustrate these connecting processes are presented.

  9. PHENOLIC CONTENT AND ANTIOXIDANT ACTIVITY OF SUPERCRITICAL CARBON DIOXIDE TREATED AND AIR-CLASSIFIED OAT BRAN CONCENTRATE MICROWAVE-IRRADIATED IN SOLVENTS AT VARYING TEMPERATURES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In addition to health-beneficial beta-glucans, oats contain phenolic compounds (PC) and other antioxidant activity (AA). We investigated processing technologies to produce oat ingredients with concentrated levels of PC and AA. Oat bran concentrate (OBC) had lipids removed by supercritical carbon d...

  10. Low-level laser irradiation improves functional recovery and nerve regeneration in sciatic nerve crush rat injury model.

    PubMed

    Wang, Chau-Zen; Chen, Yi-Jen; Wang, Yan-Hsiung; Yeh, Ming-Long; Huang, Mao-Hsiung; Ho, Mei-Ling; Liang, Jen-I; Chen, Chia-Hsin

    2014-01-01

    The development of noninvasive approaches to facilitate the regeneration of post-traumatic nerve injury is important for clinical rehabilitation. In this study, we investigated the effective dose of noninvasive 808-nm low-level laser therapy (LLLT) on sciatic nerve crush rat injury model. Thirty-six male Sprague Dawley rats were divided into 6 experimental groups: a normal group with or without 808-nm LLLT at 8 J/cm(2) and a sciatic nerve crush injury group with or without 808-nm LLLT at 3, 8 or 15 J/cm(2). Rats were given consecutive transcutaneous LLLT at the crush site and sacrificed 20 days after the crush injury. Functional assessments of nerve regeneration were analyzed using the sciatic functional index (SFI) and hindlimb range of motion (ROM). Nerve regeneration was investigated by measuring the myelin sheath thickness of the sciatic nerve using transmission electron microscopy (TEM) and by analyzing the expression of growth-associated protein 43 (GAP43) in sciatic nerve using western blot and immunofluorescence staining. We found that sciatic-injured rats that were irradiated with LLLT at both 3 and 8 J/cm(2) had significantly improved SFI but that a significant improvement of ROM was only found in rats with LLLT at 8 J/cm(2). Furthermore, the myelin sheath thickness and GAP43 expression levels were significantly enhanced in sciatic nerve-crushed rats receiving 808-nm LLLT at 3 and 8 J/cm(2). Taken together, these results suggest that 808-nm LLLT at a low energy density (3 J/cm(2) and 8 J/cm(2)) is capable of enhancing sciatic nerve regeneration following a crush injury. PMID:25119457

  11. Microwave distillation-solid phase adsorbent trapping device for the determination of off-flavors, geosmin and methylisoborneol, in catfish tissue below their rejection levels

    SciTech Connect

    Conte, E.D.; Shen, C.Y.; Miller, D.W.; Perschbacher, P.W.

    1996-08-01

    Described is a rapid microwave-mediated steam distillation device for determining two predominant off-flavor compounds, geosmin and methylisoborneol, in catfish tissue. A microwave on-time of 10 min is needed to efficiently remove these off-flavor compounds from the sample matrix and trap them on a solid phase adsorbent. A minimal amount of organic solvent is used to elute the trapped compounds. The extract is then analyzed by gas chromatography with ion trap detection in the selective ion storage mode. Detection limits in the sub-parts-per-billion range are obtained with this method. 11 refs., 5 figs., 1 tab.

  12. Antitumor activity of pluripotent cell-engineered vaccines and their potential to treat lung cancer in relation to different levels of irradiation

    PubMed Central

    Zhang, Yan-na; Duan, Xiao-gang; Zhang, Wen-hui; Wu, Ai-ling; Yang, Huan-Huan; Wu, Dong-ming; Wei, Yu-Quan; Chen, Xian-cheng

    2016-01-01

    Cancer stem cells (CSCs) are critical for tumor initiation/maintenance and recurrence or metastasis, so they may serve as a potential therapeutic target. However, CSC-established multitherapy resistance and immune tolerance render tumors resistant to current tumor-targeted strategies. To address this, renewable multiepitope-integrated spheroids based on placenta-derived mesenchymal stem cells (pMSCs) were X-ray-modified, at four different irradiation levels, including 80, 160, 240, and 320 Gy, as pluripotent biologics, to inoculate hosts bearing Lewis lung carcinoma (LL2) and compared with X-ray-modified common LL2 cells as control. We show that the vaccines at the 160/240 Gy irradiation levels could rapidly trigger tumor cells into the apoptosis loop and evidently prolong the tumor-bearing host’s survival cycle, in contrast to vaccines irradiated at other levels (P<0.05), with tumor-sustaining stromal cell-derived factor-1/CXCR4 pathway being selectively blockaded. Meanwhile, almost no or minimal toxicity was detected in the vaccinated hosts. Importantly, 160/240 Gy-irradiated vaccines could provoke significantly higher killing of CSCs and non-CSCs, which may provide an access to developing a novel biotherapy against lung carcinoma. PMID:27042111

  13. Effect of low level laser irradiation on the proliferation of myoblasts—the skeletal muscle precursor cells: an experimental in vitro study

    NASA Astrophysics Data System (ADS)

    Zhang, C. P.; Hao, T. L.; Chen, P.; Liang, J.; Wang, C. Z.; Kang, H. X.; Gao, R. L.; Fu, X. B.

    2011-12-01

    The aim of this paper is to study the effect of low-level laser irradiation (LLLI) on proliferation of myoblasts in culture. Myoblasts derived from rat skeletal muscle were irradiated by He-Ne laser with different doses. Compared with nonirradiated control group, the number of myoblasts increased when the cells in normal culture conditions were exposed to the laser of specific energy density. The amount of cells with proliferating cell nuclear antigen (PCNA) positive expression and the 5-bromo-2'-deoxyuridine (BrdU) incorporation rate after laser irradiation were also higher than that of the control group, suggesting that LLLL at certain doses can effectively enhance myoblasts growth activity in vitro. This study firstly demonstrated that stimulating myoblasts to enter into proliferative stage from initial resting state was an important mechanism of regeneration and repair of injured skeletal muscle promoted by LLLI in clinical treatment.

  14. Microwave-Assisted Switching of Microscopic Rings: Correlation Between Nonlinear Spin Dynamics and Critical Microwave Fields

    NASA Astrophysics Data System (ADS)

    Podbielski, Jan; Heitmann, Detlef; Grundler, Dirk

    2007-11-01

    We have studied the spin dynamics of microscopic permalloy rings at GHz frequencies. Increasing the irradiation power, we observe first nonlinear spin dynamics and second microwave-assisted switching (MAS). We explore the MAS phase diagram as a function of microwave power and frequency f and, in particular, extract the critical microwave field hc(f). Its frequency dependence reflects characteristic eigenfrequencies from both the linear and nonlinear spin-wave spectrum. By comparing hc(f) with the different susceptibilities, we gain insight into the microscopic processes which might be the basis of a predictive theory of MAS.

  15. Microwave assisted synthesis and characterization of graphene nanoplatelets

    NASA Astrophysics Data System (ADS)

    Kumar, Dinesh; Singh, Karamjit; Verma, Veena; Bhatti, H. S.

    2016-01-01

    Graphene Nanoplatelets were fabricated from expandable graphite by rapid microwave exfoliation. Expandable graphite was irradiated in microwave in full power for 3 min, then was soaked in mixed nitric acid and sulphuric acid at volume ratio of 1:1 for 24 h and re-irradiated, thus graphene nanoplatelets (GNPs) were obtained. Extensive characterization techniques showed that GNPs synthesized using this technique are highly pure with traces of oxide groups and without serious unrecoverable oxidation damage. GNPs synthesized by microwave technique have high crystallinity, with variable size and little layer thickness.

  16. Helium-neon laser irradiation of cryopreserved ram sperm enhances cytochrome c oxidase activity and ATP levels improving semen quality.

    PubMed

    Iaffaldano, N; Paventi, G; Pizzuto, R; Di Iorio, M; Bailey, J L; Manchisi, A; Passarella, S

    2016-08-01

    This study examines whether and how helium-neon laser irradiation (at fluences of 3.96-9 J/cm(2)) of cryopreserved ram sperm helps improve semen quality. Pools (n = 7) of cryopreserved ram sperm were divided into four aliquots and subjected to the treatments: no irradiation (control) or irradiation with three different energy doses. After treatment, the thawed sperm samples were compared in terms of viability, mass and progressive sperm motility, osmotic resistance, as well as DNA and acrosome integrity. In response to irradiation at 6.12 J/cm(2), mass sperm motility, progressive motility and viability increased (P < 0.05), with no significant changes observed in the other investigated properties. In parallel, an increase (P < 0.05) in ATP content was detected in the 6.12 J/cm(2)-irradiated semen samples. Because mitochondria are the main cell photoreceptors with a major role played by cytochrome c oxidase (COX), the COX reaction was monitored using cytochrome c as a substrate in both control and irradiated samples. Laser treatment resulted in a general increase in COX affinity for its substrate as well as an increase in COX activity (Vmax values), the highest activity obtained for sperm samples irradiated at 6.12 J/cm(2) (P < 0.05). Interestingly, in these irradiated sperm samples, COX activity and ATP contents were positively correlated, and, more importantly, they also showed positive correlation with motility, suggesting that the improved sperm quality observed was related to mitochondria-laser light interactions. PMID:27036659

  17. Microwave Assisted Wolff-Kishner Reduction Reaction

    NASA Astrophysics Data System (ADS)

    Parquet, Eric; Lin, Qun

    1997-10-01

    A Wolff-Kishner reduction of a carbonyl group was carried out in a household microwave oven. Isatin was first converted to the hydrazone with 55% hydrazine and ethylene glycol by irradiation in the microwave oven at medium power for 30 seconds. Then, isatin 3-hydrazone was mixed with ethylene glycol and potassium hydroxide and irradiated in the microwave oven for only 10 seconds. After simple work-up and recrystallization, oxindole was obtained in a yield of 32.4%. The two step syntheses described here offer several advantages: (1) very short reaction time with no need for special microscale glassware, (2) mild experimental conditions (hot oil baths and heating mantles are not required), (3) the reagents are easy to handle (students do not need to prepare sodium ethoxide from sodium metal and absolute ethanol).

  18. Microwave responses of the western North Atlantic

    NASA Technical Reports Server (NTRS)

    Stacey, J. M.; Girard, M. A.

    1985-01-01

    Features and objects in the Western North Atlantic Ocean - the Eastern Seaboard of the United States - are observed from Earth orbit by passive microwaves. The intensities of their radiated flux signatures are measured and displayed in color as a microwave flux image. The features of flux emitting objects such as the course of the Gulf Stream and the occurrence of cold eddies near the Gulf Stream are identified by contoured patterns of relative flux intensities. The flux signatures of ships and their wakes are displayed and discussed. Metal data buoys and aircraft are detected. Signal to clutter ratios and probabilities of detection are computed from their measured irradiances. Theoretical models and the range equations that explain passive microwave detection using the irradiances of natural sources are summarized.

  19. CHEMICAL SYNTHESES IN AQUEOUS MEDIA USING MICROWAVES

    EPA Science Inventory

    The development of efficient, selective and eco-friendly synthetic methods has remained a major focus of our research group. Microwave (MW) irradiation as alternative energy source in conjunction with water as reaction media has proven to be a successful 'greener' chemical appro...

  20. Effects of pulsed microwaves at 1. 28 and 5. 62 ghz on rhesus monkeys (Macaca mulatta) performing an exercise task at three levels of work. Final report

    SciTech Connect

    Knepton, J.; de Lorge, J.; Griner, T.

    1983-03-10

    The present experiment studies both behavioral and physiological consequences of exposing exercising rhesus monkeys to microwave radiation. At 1.28 Ghz four of the monkeys were exposed to power densities of 25, 41, and 89 mW/sg cm. At the highest power density exercising animals consistently had a lower response rate, a higher heart rate, and a greater increase in colonic temperature. At lower power densities the effects were generally less evident and were idiosyncratic. At 5.62 GHz five monkeys were exposed to power densities of 25, 41, and 89 mW/sg cm. Differences from controls were found only at 43 mW/sq cm: (1) colonic temperature averaged +0.8 C higher (N=2), (2) response rate decreased (N=5) when the heaviest work load occurred during the terminal third of the session, and (3) heart rate (N=2) was higher. These experiments demonstrate the microwaves will produce cardiovascular effects in addition to those produced by exercise alone and that body temperature induced by microwave energy does not seem to be further accelerated by exercise. The results also illustrate that monkeys working a physically arduous task are more likely to stop working when exposed to microwave than when working a less arduous task.

  1. Effect of chronic microwave radiation on T cell-mediated immunity in the rabbit.

    PubMed

    Nageswari, K S; Sarma, K R; Rajvanshi, V S; Sharan, R; Sharma, M; Barathwal, V; Singh, V

    1991-09-01

    Experiments were conducted to elucidate the effects of chronic low power-level microwave radiation on the immunological systems of rabbits. Fourteen male Belgian white rabbits were exposed to microwave radiation at 5 mW/cm2, 2.1 GHz, 3 h daily, 6 days/week for 3 months in two batches of 7 each in specially designed miniature anechoic chambers. Seven rabbits were subjected to sham exposure for identical duration. The microwave energy was provided through S band standard gain horns connected to a 4K3SJ2 Klystron power amplifier. The first batch of animals were assessed for T lymphocyte-mediated cellular immune response mechanisms and the second batch of animals for B lymphocyte-mediated humoral immune response mechanisms. The peripheral blood samples collected monthly during microwave/sham exposure and during follow-up (5/14 days after termination of exposures, in the second batch animals only) were analysed for T lymphocyte numbers and their mitogen responsiveness to ConA and PHA. Significant suppression of T lymphocyte numbers was noted in the microwave group at 2 months (P less than 0.01, delta % 21.5%) and during follow-up (P less than 0.01, delta % 30.2%). The first batch animals were initially sensitised with BCG and challenged with tuberculin (0.03 ml) at the termination of microwave irradiation/sham exposure and the increase in foot pad thickness (delta mm), which is a measure of T cell-mediated immunity (delayed type hypersensitivity response, DTH) was noted in both the groups. The microwave group revealed a better response than the control group (delta % +12.4 vs. +7.54). The animals were sacrificed and the tissue T lymphocyte counts (spleen and lymph node) were analysed.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1743776

  2. Method and apparatus for thickness measurement using microwaves

    DOEpatents

    Woskov, Paul [Bedford, MA; Lamar, David A [West Richland, WA

    2001-01-01

    The method for measuring the thickness of a material which transmits a detectable amount of microwave radiation includes irradiating the material with coherent microwave radiation tuned over a frequency range. Reflected microwave radiation is detected, the reflected radiation having maxima and minima over the frequency range as a result of coherent interference of microwaves reflected from reflecting surfaces of the material. The thickness of the material is determined from the period of the maxima and minima along with knowledge of the index of refraction of the material.

  3. Bonding PMMA microfluidics using commercial microwave ovens

    NASA Astrophysics Data System (ADS)

    Toossi, A.; Moghadas, H.; Daneshmand, M.; Sameoto, D.

    2015-08-01

    In this paper, a novel low-cost, rapid substrate-bonding technique is successfully applied to polymethyl methacrylate (PMMA) microfluidics bonding for the first time. This technique uses a thin intermediate metallic microwave susceptor layer at the interface of the bonding site (microchannels) which produces localized heating required for bonding during microwave irradiation. The metallic susceptor pattern is designed using a multiphysics simulation model developed in ANSYS Multiphysics software (high-frequency structural simulation (HFSS) coupled with ANSYS-Thermal). In our experiments, the required microwave energy for bonding is delivered using a relatively inexpensive, widely accessible commercial microwave oven. Using this technique, simple PMMA microfluidics prototypes are successfully bonded and sealed in less than 35 seconds with a minimum measured bond strength of 1.375 MPa.

  4. A Robust, Microwave Rain Gauge

    NASA Astrophysics Data System (ADS)

    Mansheim, T. J.; Niemeier, J. J.; Kruger, A.

    2008-12-01

    Researchers at The University of Iowa have developed an all-electronic rain gauge that uses microwave sensors operating at either 10 GHz or 23 GHz, and measures the Doppler shift caused by falling raindrops. It is straightforward to interface these sensors with conventional data loggers, or integrate them into a wireless sensor network. A disadvantage of these microwave rain gauges is that they consume significant power when they are operating. However, this may be partially negated by using data loggers' or sensors networks' sleep-wake-sleep mechanism. Advantages of the microwave rain gauges are that one can make them very robust, they cannot clog, they don't have mechanical parts that wear out, and they don't have to be perfectly level. Prototype microwave rain gauges were collocated with tipping-bucket rain gauges, and data were collected for two seasons. At higher rain rates, microwave rain gauge measurements compare well with tipping-bucket measurements. At lower rain rates, the microwave rain gauges provide more detailed information than tipping buckets, which quantize measurement typically in 1 tip per 0.01 inch, or 1 tip per mm of rainfall.

  5. In-office microwave disinfection of soft contact lenses

    SciTech Connect

    Harris, M.G.; Rechberger, J.; Grant, T.; Holden, B.A. )

    1990-02-01

    We evaluated the effectiveness of an in-office microwave disinfection procedure which allowed for the disinfection of up to 40 soft contact lenses at one time. Ciba AOSept cases filled with sterile unpreserved saline were contaminated with one of six FDA test challenge microorganisms at a concentration of approximately 10(3) colony forming units per milliliter (CFU/ml). Twenty cases were placed on the rotating plate of a standard 2450 MHz 650 W microwave oven in a 10-cm diameter circle. The cases were exposed to high intensity microwave irradiation for periods of 0 to 15 min. None of the 6 microorganisms evaluated survived 2 min or longer of microwave exposure. Our findings indicated that microwave irradiation can be a convenient, rapid, and effective method of disinfecting a number of soft contact lenses at one time and thus adaptable as an in-office soft contact lens disinfection procedure.

  6. Macrophages From Irradiated Tumors Express Higher Levels of iNOS, Arginase-I and COX-2, and Promote Tumor Growth

    SciTech Connect

    Tsai, C.-S.; Chen, F.-H.; Wang, C.-C.; Huang, H.-L.; Jung, Shih-Ming; Wu, C.-J.; Lee, C.-C.; McBride, William H.; Chiang, C.-S.; Hong, J.-H. . E-mail: jihong@adm.cgmh.org.tw

    2007-06-01

    Purpose: To investigate the effects of single and fractionated doses of radiation on tumors and tumor-associated macrophages (TAMs), and to elucidate the potential of TAMs to influence tumor growth. Methods and Materials: A murine prostate cell line, TRAMP-C1, was grown in C57Bl/6J mice to 4-mm tumor diameter and irradiated with either 25 Gy in a single dose, or 60 Gy in 15 fractions. The tumors were removed at the indicated times and assessed for a variety of markers related to TAM content, activation status, and function. Results: In tumors receiving a single radiation dose, arginase (Arg-I), and cycloxygenase-2 (COX-2) mRNA expression increased as a small transient wave within 24 h and a larger persistent wave starting after 3 days. Inducible nitric oxide synthase (iNOS) mRNA was elevated only after 3 days and continued to increase up to 3 weeks. After fractionated irradiation, Arg-1 and COX-2 mRNA levels increased within 5 days, whereas iNOS was increased only after 10 fractions of irradiation had been given. Increased levels of Arg-I, COX-2, and, to a lesser extent, iNOS protein were found to associate with TAMs 1-2 weeks after tumor irradiation. Function of TAMs were compared by mixing them with TRAMP-C1 cells and injecting them into mice; TRAMP-C1 cells mixed with TAMs from irradiated tumors appeared earlier and grew significantly faster than those mixed with TAMs from unirradiated tumors or TRAMP-C1 alone. Conclusions: Tumor-associated macrophages in the postirradiated tumor microenvironment express higher levels of Arg-1, COX-2, and iNOS, and promote early tumor growth in vivo.

  7. B1 Sequence-Based Real-Time Quantitative PCR: A Sensitive Method for Direct Measurement of Mouse Plasma DNA Levels After Gamma Irradiation

    SciTech Connect

    Zhang Hengshan; Zhang, Steven B.; Sun Weimin; Yang Shanmin; Zhang Mei; Wang Wei; Liu Chaomei; Zhang Kunzhong; Swarts, Steven; Fenton, Bruce M.; Keng, Peter; Maguire, David; Okunieff, Paul Zhang Lurong

    2009-08-01

    Purpose: Current biodosimetric techniques for determining radiation exposure have inherent delays, as well as quantitation and interpretation limitations. We have identified a new technique with the advantage of directly measuring circulating DNA by amplifying inter-B1 regions in the mouse genome, providing a sensitive method for quantitating plasma DNA. Methods and Materials: Real-time quantitative polymerase chain reaction (PCR) was used to detect levels of DNA by amplifying inter-B1 genomic DNA in plasma samples collected at 0-48 h from mice receiving 0-10 Gy total- or partial-body irradiation ({sup 137}Cs {gamma}-ray source at {approx}1.86 Gy/min; homogeneity: {+-} 6.5%). Results: The correlation coefficient between DNA levels and the threshold cycle value (C{sub T}) was 0.996, and the average recoveries of DNA in the assay were 87%. This assay revealed that when BALB/c mice were exposed to 10 Gy total-body irradiation (TBI), plasma DNA levels gradually increased beginning at 3 h after irradiation, peaked at 9 h, and returned to baseline within 48 h. Increased plasma DNA levels were also detected following upper-torso or lower-torso partial-body irradiation; however, TBI approximately doubled those plasma DNA levels at the same radiation dose. This technique therefore reflects total body cell damage. The advantages of this assay are that DNA extraction is not required, the assay is highly sensitive (0.002 ng), and results can be obtained within 2.5 h after collection of plasma samples. Conclusions: A radiation dose-dependent increase of plasma DNA was observed in the dose range from 2 to 10 Gy, suggesting that plasma DNA may be a useful radiation biomarker and adjunct to existing cell-based assays.

  8. Decreased expression levels of cell cycle regulators and matrix metalloproteinases in melanoma from RET-transgenic mice by single irradiation of non-equilibrium atmospheric pressure plasmas

    PubMed Central

    Iida, Machiko; Omata, Yasuhiro; Nakano, Chihiro; Yajima, Ichiro; Tsuzuki, Toyonori; Ishikawa, Kenji; Hori, Masaru; Kato, Masashi

    2015-01-01

    Since effective therapies for melanoma with BRAFV600E mutation are being developed, interest has been shown in the development of therapies for melanoma without BRAFV600E mutation. Recently, interest has also been shown in medical application of non-nequilibrium atmospheric pressure plasmas (NEAPPs). We previously suggested that repeated NEAPP irradiation to spontaneously developed benign melanocytic tumors in RFP-RET-transgenic mice (RET-mice) not only suppresses tumor growth but also prevents malignant transformation. In this study, we first confirmed that transcript expression levels of tumor growth regulators (CyclinD1, D2, E1, E2, G2 and PCNA but not CyclinG1) and tumor invasion regulators [Matrix metalloproteinase (MMP)-2, -9 and -14 and melanoma cell adhesion molecule (MCAM)] in melanomas were significantly higher than those in benign melanocytic tumors in RET-mice. We then showed that transcript expression levels of CyclinE1, G1 and G2 and MMP-2 and -9 in melanomas from RET-mice were significantly decreased by single NEAPP irradiation, whereas transcript expression levels of CyclinD1, D2, E2, PCNA, MCAM and MMP-14 were comparable in untreated and NEAPP-treated melanomas. Since no BrafV600E mutation melanomas have been found in RET-mice, our results suggest that single NEAPP irradiation is a potential therapeutic tool for melanoma without BRAFV600E mutation through modulation of the expression levels of tumor growth and invasion regulators. PMID:26464684

  9. TERT alleviates irradiation-induced late rectal injury by reducing hypoxia-induced ROS levels through the activation of NF-κB and autophagy.

    PubMed

    Liu, Qi; Sun, Yong; Lv, Yuefeng; Le, Ziyu; Xin, Yuhu; Zhang, Ping; Liu, Yong

    2016-09-01

    The hypoxic microenvironment which is present following irradiation has been proven to promote radiation-induced injury to normal tissues. Previous studies have demonstrated that telomerase reverse transcriptase (TERT) is regulated by hypoxia, and that it plays a protective role in the process of wound repair. However, its effects on radiation-induced injury remain unclear. In this study, we examined the effects of human TERT on irradiation-induced late rectal injury in fibroblasts under hypoxic conditions. We also performed in vivo experiments. The rectums of 5-week‑old female C57BL/6N mice were irradiated locally with a single dose of 25 Gy. We then examined the fibrotic changes using hematoxylin and eosin staining, and Masson's staining. The expression of hypoxia inducible factor-1α (HIF-1α) and TERT was analyzed by immunohistochemistry. In in vitro experiments, apoptosis, reactive oxygen species (ROS) production and the autophagy level induced by exposure to hypoxia were assayed in fibroblasts. The association between TERT, nuclear factor-κB (NF-κB) and the autophagy level was examined by western blot analysis. The antioxidant effects of TERT were examined on the basis of the ratio of glutathione to glutathione disulfide (GSH/GSSG) and mitochondrial membrane potential. Rectal fibrosis was induced significantly at 12 weeks following irradiation. The HIF-1α and TERT expression levels increased in the fibrotic region. The TERT‑overexpressing fibroblasts (transfected with an hTERT-expressing lentiviral vector) exhibited reduced apoptosis, reduced ROS production, a higher autophagy level, a higher GSH/GSSG ratio and stable mitochondrial membrane potential compared with the fibroblasts in which TERT had been silenced by siRNA. NF-κB was activated by TERT, and the inhibition of TERT reduced the autophagy level in the fibroblasts. These results demonstrate that TERT decreases cellular ROS production, while maintaining mitochondrial function and

  10. TERT alleviates irradiation-induced late rectal injury by reducing hypoxia-induced ROS levels through the activation of NF-κB and autophagy

    PubMed Central

    Liu, Qi; Sun, Yong; Lv, Yuefeng; Le, Ziyu; Xin, Yuhu; Zhang, Ping; Liu, Yong

    2016-01-01

    The hypoxic microenvironment which is present following irradiation has been proven to promote radiation-induced injury to normal tissues. Previous studies have demonstrated that telomerase reverse transcriptase (TERT) is regulated by hypoxia, and that it plays a protective role in the process of wound repair. However, its effects on radiation-induced injury remain unclear. In this study, we examined the effects of human TERT on irradiation-induced late rectal injury in fibroblasts under hypoxic conditions. We also performed in vivo experiments. The rectums of 5-week-old female C57BL/6N mice were irradiated locally with a single dose of 25 Gy. We then examined the fibrotic changes using hematoxylin and eosin staining, and Masson's staining. The expression of hypoxia inducible factor-1α (HIF-1α) and TERT was analyzed by immunohistochemistry. In in vitro experiments, apoptosis, reactive oxygen species (ROS) production and the autophagy level induced by exposure to hypoxia were assayed in fibroblasts. The association between TERT, nuclear factor-κB (NF-κB) and the autophagy level was examined by western blot analysis. The antioxidant effects of TERT were examined on the basis of the ratio of glutathione to glutathione disulfide (GSH/GSSG) and mitochondrial membrane potential. Rectal fibrosis was induced significantly at 12 weeks following irradiation. The HIF-1α and TERT expression levels increased in the fibrotic region. The TERT-overexpressing fibroblasts (transfected with an hTERT-expressing lentiviral vector) exhibited reduced apoptosis, reduced ROS production, a higher autophagy level, a higher GSH/GSSG ratio and stable mitochondrial membrane potential compared with the fibroblasts in which TERT had been silenced by siRNA. NF-κB was activated by TERT, and the inhibition of TERT reduced the autophagy level in the fibroblasts. These results demonstrate that TERT decreases cellular ROS production, while maintaining mitochondrial function and protecting the

  11. The issue of 'molecular radiators' in microwave-assisted reactions. Computational calculations on ring closing metathesis (RCM).

    PubMed

    Rodríguez, A M; Prieto, P; de la Hoz, A; Díaz-Ortiz, A; García, J I

    2014-04-21

    A DFT computational mechanistic study of the ring closing metathesis (RCM) reaction of diallyl ether or N,N-diallyl-p-toluenesulfonamide catalyzed by a second generation Grubbs-type ruthenium carbene complex has been carried out. This study was performed at the PCM(CH2Cl2)-B3LYP/6-311+G(2d,p)//B3LYP/SDD theory level. The aim of this work was to shed light on the influence that microwave irradiation has on these reactions and to gain insight into the so-called 'molecular radiator' effect. The outcomes obtained indicate that thermal effects induced by microwave irradiation decrease the catalytic induction period. The presence of a polar reagent and/or polar species in the reaction that increases the polarity of the medium may enhance this thermal effect. PMID:24599220

  12. Effects of microwave radiation on the lens of the eye

    SciTech Connect

    Not Available

    1981-01-01

    The effects of microwave radiation on the lens of the eye, particularly in regard to potential for cataractogenesis at low exposure levels are examined. The partially understood biophysical mechanism of microwave cataractogenesis is discussed. No evidence was found for cataract induction by microwave fields of less than 10 per sq cm.

  13. High levels of reactive oxygen species in gold nanoparticle-targeted cancer cells following femtosecond pulse irradiation

    NASA Astrophysics Data System (ADS)

    Minai, Limor; Yeheskely-Hayon, Daniella; Yelin, Dvir

    2013-07-01

    Cancer cells could be locally damaged using specifically targeted gold nanoparticles and laser pulse irradiation, while maintaining minimum damage to nearby, particle-free tissue. Here, we show that in addition to the immediate photothermal cell damage, high concentrations of reactive oxygen species (ROS) are formed within the irradiated cells. Burkitt lymphoma B cells and epithelial breast cancer cells were targeted by antibody-coated gold nanospheres and irradiated by a few resonant femtosecond pulses, resulting in significant elevation of intracellular ROS which was characterized and quantified using time-lapse microscopy of different fluorescent markers. The results suggest that techniques that involve targeting of various malignancies using gold nanoparticles and ultrashort pulses may be more effective and versatile than previously anticipated, allowing diverse, highly specific set of tools for local cancer therapy.

  14. High levels of reactive oxygen species in gold nanoparticle-targeted cancer cells following femtosecond pulse irradiation.

    PubMed

    Minai, Limor; Yeheskely-Hayon, Daniella; Yelin, Dvir

    2013-01-01

    Cancer cells could be locally damaged using specifically targeted gold nanoparticles and laser pulse irradiation, while maintaining minimum damage to nearby, particle-free tissue. Here, we show that in addition to the immediate photothermal cell damage, high concentrations of reactive oxygen species (ROS) are formed within the irradiated cells. Burkitt lymphoma B cells and epithelial breast cancer cells were targeted by antibody-coated gold nanospheres and irradiated by a few resonant femtosecond pulses, resulting in significant elevation of intracellular ROS which was characterized and quantified using time-lapse microscopy of different fluorescent markers. The results suggest that techniques that involve targeting of various malignancies using gold nanoparticles and ultrashort pulses may be more effective and versatile than previously anticipated, allowing diverse, highly specific set of tools for local cancer therapy. PMID:23828378

  15. Evidence for two distinct defects contributing to the H4 deep-level transient spectroscopy peak in electron-irradiated InP

    NASA Astrophysics Data System (ADS)

    Massarani, B.; Awad, F. G.; Kaaka, M.; Darwich, R.

    1998-12-01

    Deep-level transient spectroscopy (DLTS) has been used to study the dominant deep-level H4 produced in InP by electron irradiation. The characteristics of the H4 peak in Zn-doped InP has been studied as a function of pulse duration (tp) before and after annealing. Our results show that at least two traps contribute to the H4 peak: one is a fast trap (labeled H4F) and the other is a slow trap (labeled H4S). This is shown through several results concerning the activation energy, the capture cross section, the full width at half-maximum, and the peak temperature shift. It is shown that both traps are irradiation defects created in the P sublattice.

  16. Carbon nanotubes and microwaves: interactions, responses, and applications.

    PubMed

    Vázquez, Ester; Prato, Maurizio

    2009-12-22

    The interaction of microwaves with carbon nanotubes (CNTs) is an interesting topic for a variety of potential applications. Microwaves have been used for the purification of CNTs and for their chemical functionalization, providing a technique for simple, green, and large-scale protocols. In addition, the selective destruction of metallic CNTs under microwave irradiation could potentially result in a batch of semiconducting-only nanotubes. As an innovative application, the combination of microwaves with well-aligned CNTs could produce a new illumination technology. Moreover, the microwave absorbing properties of CNTs and their different behavior from typical organic compounds may open the door to the preparation of a wide range of new materials useful in many fields. A few examples of practical applications include electromagnetic interference for protecting the environment from radiation and microwave hyperthermia for cancer treatment as well as other medical therapies requiring precise heating of biological tissues. PMID:20025299

  17. Absence of deleterious effects of chronic microwave radiation on the eyes of rhesus monkeys

    SciTech Connect

    McAfee, R.D.; Ortiz-Lugo, R.; Bishop, R.; Gordon, R.

    1983-10-01

    Microwave irradiation of rhesus monkeys' eyes at 9.31 and 2.45 GHz and at an average power density of 150 mW per centimeter square is reported. Irradiation, beginning in 1976, of 17 monkeys (Macaca mulatta) was accomplished without restraint or anesthesia by training the monkeys to irradiate themselves. To data microwave radiation of these monkeys has not resulted in deleterious ocular effects.

  18. Microwave-assisted synthesis of highly fluorescent nanoparticles of a melamine-based porous covalent organic framework for trace-level detection of nitroaromatic explosives.

    PubMed

    Zhang, Wang; Qiu, Ling-Guang; Yuan, Yu-Peng; Xie, An-Jian; Shen, Yu-Hua; Zhu, Jun-Fa

    2012-06-30

    Covalent organic frameworks (COFs) are a new generation of porous materials constructed from light elements linked by strong covalent bonds. Herein we present rapid preparation of highly fluorescent nanoparticles of a new type of COF, i.e. melamine-based porous polymeric network SNW-1, by a microwave-assisted synthesis route. Although the synthesis of SNW-1 has to be carried out at 180°C for 3d under conventional reflux conditions, SNW-1 nanoparticles could be obtained in 6h by using such a microwave-assisted method. The results obtained have clearly demonstrated that microwave-assisted synthesis is a simple yet highly efficient approach to nanoscale COFs or other porous polymeric materials. Remarkably, the as-synthesized SNW-1 nanoparticles exhibit extremely high sensitivity and selectivity, as well as fast response to nitroaromatic explosives such as 2,4,6-trinitrotoluene (TNT), 2,4,6-trinitrophenylmethylnitramine (Tetryl) and picric acid (PA) without interference by common organic solvents, which is due to the nanoscaled size and unique hierarchical porosity of such fluorescence-based sensing material. PMID:22560174

  19. The Effect of Low-Level Laser Irradiation on Sperm Motility, and Integrity of the Plasma Membrane and Acrosome in Cryopreserved Bovine Sperm

    PubMed Central

    Fernandes, Guilherme Henrique C.; de Carvalho, Paulo de Tarso Camillo; Serra, Andrey Jorge; Crespilho, André Maciel; Peron, Jean Pierre Schatzman; Rossato, Cristiano; Leal-Junior, Ernesto Cesar Pinto; Albertini, Regiane

    2015-01-01

    Background and Objective Freezing changes sperm integrity remarkably. Cryopreservation involves cooling, freezing, and thawing and all these contribute to structural damage in sperm, resulting in reduced fertility potential. Low-level laser irradiation (LLLI) could increase energy supply to the cell and cause reactive oxygen species reduction (ROS), contributing to the restoration of oxygen consumption and adenosine triphosphate synthesis (ATP) in the mitochondria. Our goal was to analyze the effects of low-level laser irradiation on sperm motility and integrity of the plasma membrane and acrosome in cryopreserved bovine sperm. Study Design/Materials and Methods We analyzed 09 samples of bull semen (Bos taurus indicus), divided into three groups: a control group without laser irradiation, a 4J group subjected to a laser irradiation dose of 4 joules, and a 6J group subjected to dose of 6 joules. Samples were divided for the analysis of cell viability and acrosomal membrane integrity using flow cytometry; another portion was used for motion analysis. Irradiation was performed in petri dishes of 30 mm containing 3 ml of semen by an aluminum gallium indium phosphide laser diode with a wavelength of 660 nm, 30 mW power, and energy of 4 and 6 joules for 80 and 120 seconds respectively. Subsequently, the irradiated and control semen samples were subjected to cryopreservation and analyzed by flow cytometry (7AAD and FITC-PSA) using the ISAS - Integrated Semen Analysis System. Results Flow cytometry showed an increase in the percentage of live sperm cells and acrosome integrity in relation to control cells when subjected to irradiation of low-power laser in two different doses of 4 and 6 joules (p < 0.05). In the analysis of straightness, percentage of cell movement, and motility, a dose of 4 joules was more effective (p < 0.05). Conclusion We conclude that LLLI may exert beneficial effects in the preservation of live sperm. A dose of 4 joules prior to cryopreservation was

  20. Microwave discharge electrodeless lamps (MDEL). Part IV. Novel self-ignition system incorporating metallic microwave condensing cones to activate MDELs in photochemical reactions.

    PubMed

    Horikoshi, Satoshi; Tsuchida, Akihiro; Sakai, Hideki; Abe, Masahiko; Sato, Susumu; Serpone, Nick

    2009-11-01

    A metallic condensing cone that concentrates microwave radiation (equivalent to an optical lens) has been developed and used as part of a system to activate a microwave discharge electrodeless lamp (MDEL) in the oxidative treatment of wastewaters by aiding the novel self-ignition of the lamp on irradiation at low microwave power levels. This approach to self-ignition can potentially lead to considerable energy savings in such treatments. System performance was examined for the ignition power of microwaves of such MDEL devices in water, whose usefulness was assessed by investigating the photolytic transformation of aqueous solutions of representatives of three classes of contaminants: chlorinated phenols, herbicides and endocrine disruptors, specifically 4-chlorophenol (4-CP), 2,4-dichlorophenoxyacetic acid (2,4-D) and 4,4'-isopropylidenediphenol (bisphenol-A; BPA), respectively, taken as model wastewaters in air-equilibrated, in oxygen-saturated and in TiO2-containing aqueous media. The results are discussed in terms of the dynamics of the photo-induced degradation processes. PMID:19862422

  1. Observation of microwave superfluid phenomena of multiple phase magnetic fluid

    NASA Astrophysics Data System (ADS)

    Kono, Kazuhito; Kono, Buhei

    2015-05-01

    We observe superfluid phenomena by microwaves irradiation to multiple phase magnetic fluid in room temperature or room pressure. Ferromagnetism transformation of diamagnetic or paramagnetic particles in multiple phase magnetic fluid containing constant rate of ferromagnetic particles, diamagnetic or paramagnetic particles mixing organic polyphenol and irradiation of microwaves is, observed by superexchange interaction. Superfluid phenomena are observed by irradiation of microwaves to aforementioned multiple phase of magnetic fluid containing ferromagnetism transformed diamagnetic or paramagnetic particles with ferromagnetic particles. Mixing semiconductor pigments amplifying superfluid energy by photosensitivity is observed. Visible light LED selecting wavelength is irradiated to superfluid condition of aforementioned multiple phase magnetic fluid thus magnetic field and energy of superfluid is enhanced by light quantum amplification effect.

  2. Microwave torrefaction of rice straw and Pennisetum.

    PubMed

    Huang, Y F; Chen, W R; Chiueh, P T; Kuan, W H; Lo, S L

    2012-11-01

    Microwave torrefaction of rice straw and pennisetum was researched in this article. Higher microwave power levels contributed to higher heating rate and reaction temperature, and thus produced the torrefied biomass with higher heating value and lower H/C and O/C ratios. Kinetic parameters were determined with good coefficients of determination, so the microwave torrefaction of biomass might be very close to first-order reaction. Only 150W microwave power levels and 10min processing time were needed to meet about 70% mass yield and 80% energy yield for torrefied biomass. The energy density of torrefied biomass was about 14% higher than that of raw biomass. The byproducts (liquid and gas) possessed about 30% mass and 20% energy of raw biomass, and they can be seen as energy sources for heat or electricity. Microwave torrefaction of biomass could be a competitive technology to employ the least energy and to retain the most bioenergy. PMID:22929739

  3. Effect of gamma irradiation treatment at phytosanitary dose levels on the quality of ‘Lane Late’ navel oranges

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study were to determine the dose tolerance of ‘Lane Late’ navel oranges (Citrus sinensis L. Osbeck) to irradiation for phytosanitary purposes, identify the sensory attributes that may be affected by the treatment, and determine which changes, if any, influence consumer liking....

  4. Microwave continuous sterilization of injection ampoules.

    PubMed

    Sasaki, K; Honda, W; Shimizu, K; Iizima, K; Ehara, T; Okuzawa, K; Miyake, Y

    1996-01-01

    A new microwave continuous sterilizer (MWS) for applying microwave dielectric heating as an alternative to an autoclave was developed. The developmental objectives of the MWS were: 1. Achieving sufficient sterilization for the drugs containing heat-sensitive ingredients. 2. Measuring and recording sterilization temperature of each ampoule. 3. Ensuring automatic continuous operation and linkage with the preceding and following machines in an injection ampoule production process. The temperature of the drug solution in an ampoule was heated to 140 degrees C within about 30 seconds by the MWS. Target F0 value is achieved through the maintaining heater to maintain the target temperature for 12 seconds. Ampoules are cooled with air and water after completion of heating. The MWS is capable of processing 150 ampoules per minute. The newly developed techniques which minimized temperature distribution of heated ampoule solution were: 1. Microwave irradiation in a direction opposite to the direction of ampoules transportation. 2. Microwave irradiation in the lower part of ampoule solution (i.e., heating up the drug solution by thermal convection.) 3. Microwave power control by feedback of measured temperatures. 4. Heating rate control corresponding to the dielectric property of ampoule solution. The drug stability test was performed using 3% pyridoxamine phosphate solution, and the inactivation of spores in 3% pyridoxamine phosphate solution was examined using Bacillus stearothermophilus ATCC 7953 spores. The MWS was proved to have an adequate efficiency of sterilization with less chemical degradation of the contents than an autoclave. PMID:8696781

  5. Microwave vegetation indices derived from satellite microwave radiometers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vegetation indices are valuable in many fields of geosciences. Conventional, visible-near infrared, indices are often limited by the effects of atmosphere, background soil conditions, and saturation at high levels of vegetation. In this study, the theoretical basis for a new type of passive microwav...

  6. Sustainable Synthesis of Nanomaterials Using Microwave irradiation

    EPA Science Inventory

    The presentation summarizes our recent activity in MW-assisted synthesis of nanomaterials under benign conditions. Shape-controlled aqueous synthesis of noble nanostructures via MW-assisted spontaneous reduction of noble metal salts using -D-glucose, sucrose, and maltose will be...

  7. Noninvasive Monitoring of Microvascular Changes With Partial Irradiation Using Dynamic Contrast-Enhanced and Blood Oxygen Level-Dependent Magnetic Resonance Imaging

    SciTech Connect

    Lin, Yu-Chun; Wang, Jiun-Jie; Hong, Ji-Hong; Lin, Yi-Ping; Lee, Chung-Chi; Wai, Yau-Yau; Ng, Shu-Hang; Wu, Yi-Ming; Wang, Chun-Chieh

    2013-04-01

    Purpose: The microvasculature of a tumor plays an important role in its response to radiation therapy. Dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) and blood oxygen level-dependent (BOLD) MRI are both sensitive to vascular characteristics. The present study proposed a partial irradiation approach to a xenograft tumor to investigate the intratumoral response to radiation therapy using DCE and BOLD MRI. Methods and Materials: TRAMP-C1 tumors were grown in C57BL/6J mice. Partial irradiation was performed on the distal half of the tumor with a single dose of 15 Gy. DCE MRI was performed to derive the endothelium transfer constant, K{sup trans}, using pharmacokinetic analysis. BOLD MRI was performed using quantitative R2* measurements with carbogen breathing. The histology of the tumor was analyzed using hematoxylin and eosin staining and CD31 staining to detect endothelial cells. The differences between the irradiated and nonirradiated regions of the tumor were assessed using K{sup trans} values, ΔR2* values in response to carbogen and microvascular density (MVD) measurements. Results: A significantly increased K{sup trans} and reduced BOLD response to carbogen were found in the irradiated region of the tumor compared with the nonirradiated region (P<.05). Histologic analysis showed a significant aggregation of giant cells and a reduced MVD in the irradiated region of the tumor. The radiation-induced difference in the BOLD response was associated with differences in MVD and K{sup trans}. Conclusions: We demonstrated that DCE MRI and carbogen-challenge BOLD MRI can detect differential responses within a tumor that may potentially serve as noninvasive imaging biomarkers to detect microvascular changes in response to radiation therapy.

  8. The Lack of Cytotoxic Effect and Radioadaptive Response in Splenocytes of Mice Exposed to Low Level Internal β-Particle Irradiation through Tritiated Drinking Water in Vivo

    PubMed Central

    Flegal, Matthew; Blimkie, Melinda; Roch-Lefevre, Sandrine; Gregoire, Eric; Klokov, Dmitry

    2013-01-01

    Health effects of tritium, a β-emitter and a by-product of the nuclear industry, is a subject of significant controversy. This mouse in vivo study was undertaken to monitor biological effects of low level tritium exposure. Mice were exposed to tritiated drinking water (HTO) at 10 KBq/L, 1 MBq/L and 20 MBq/L concentrations for one month. The treatment did not result in a significant increase of apoptosis in splenocytes. To examine if this low level tritium exposure alters radiosensitivity, the extracted splenocytes were challenged in vitro with 2 Gy γ-radiation, and apoptotic responses at 1 and 24 h were measured. No alterations in the radiosensitivity were detected in cells from mice exposed to tritium compared to sham-treated mice. In contrast, low dose γ-irradiation at 20 or 100 mGy, resulted in a significant increase in resistance to apoptotic cell death after 2 Gy irradiation; an indication of the radioadaptive response. Overall, our data suggest that low concentrations of tritium given to mice as HTO in drinking water do not exert cytotoxic effect in splenocytes, nor do they change cellular sensitivity to additional high dose γ-radiation. The latter may be considered as the lack of a radioadaptive response, typically observed after low dose γ-irradiation. PMID:24317437

  9. Mtf-1 lymphoma-susceptibility locus affects retention of large thymocytes with high ROS levels in mice after {gamma}-irradiation

    SciTech Connect

    Maruyama, Masaki; Yamamoto, Takashi; Kohara, Yuki; Katsuragi, Yoshinori; Mishima, Yukio; Aoyagi, Yutaka; Kominami, Ryo; E-mail: rykomina@med.niigata-u.ac.jp

    2007-03-02

    Mouse strains exhibit different susceptibilities to {gamma}-ray-induced thymic lymphomas. Our previous study identified Mtf-1 (metal responsive transcription factor-1) as a candidate susceptibility gene, which is involved in the radiation-induced signaling pathway that regulates the cellular reactive oxygen species (ROS). To reveal the mechanism for the increased susceptibility conferred by Mtf-1 locus, we examined early effects of {gamma}-ray on ROS levels in vivo and its difference between Mtf-1 susceptible and resistant congenic mice. Here, we show the detection of clonally growing thymocytes at 4 weeks after irradiation, indicating the start of clonal expansion at a very early stage. We also show that large thymocytes with higher ROS levels and a proliferation capacity were more numerous in the Mtf-1 susceptible mice than the resistant mice when examined at 7 days after irradiation, although such tendency was not found in mice lacking one allele of Bcl11b tumor suppressor gene. This high retention of the large thymocytes, at a high risk for ROS-induced mutation, is a compensatory proliferation and regeneration response to depletion of the thymocytes after irradiation and the response is likely to augment the development of prelymphoma cells leading to thymic lymphomas.

  10. Microwave treatment of vulcanized rubber

    DOEpatents

    Wicks, George G.; Schulz, Rebecca L.; Clark, David E.; Folz, Diane C.

    2002-07-16

    A process and resulting product is provided in which a vulcanized solid particulate, such as vulcanized crumb rubber, has select chemical bonds broken by microwave radiation. The direct application of microwaves in combination with uniform heating of the crumb rubber renders the treated crumb rubber more suitable for use in new rubber formulations. As a result, larger particle sizes and/or loading levels of the treated crumb rubber can be used in new rubber mixtures to produce recycled composite products with good properties.

  11. B1 Sequence-based real-time Quantitative PCR: A sensitive method for direct measurement of mouse plasma DNA levels after gamma irradiation

    PubMed Central

    Zhang, Hengshan; Zhang, Steven B.; Sun, Weimin; Yang, Shanmin; Zhang, Mei; Wang, Wei; Liu, Chaomei; Zhang, Kunzhong; Swarts, Steven; Fenton, Bruce M.; Keng, Peter; Maguire, David; Okunieff, Paul; Zhang, Lurong

    2010-01-01

    Purpose Current biodosimetric techniques for determining radiation exposure have inherent delays, and quantitation and interpretation limitations. We have identified a new technique with the advantage of directly measuring circulating DNA by amplifying inter-B1 regions in the mouse genome, providing a sensitive method for quantitating plasma DNA. Methods and Materials Real-time quantitative PCR was used to detect levels of DNA by amplifying inter-B1 genomic DNA in plasma samples collected at 0-48 hrs from mice receiving 0-10 Gy total- or partial-body irradiation [137Cs γ-ray source at ≈1.86 Gy/min (homogeneity: ±6.5%)]. Results The correlation coefficient between DNA levels and the threshold cycle value (CT) was 0.996, and the average recoveries of DNA in the assay were 87%. This assay revealed that when BALB/c mice were exposed to 10 Gy TBI, plasma DNA levels gradually increased beginning at 3 hours after irradiation, peaked at 9 hours, and returned to baseline within 48 hours. Increased plasma DNA levels were also detected following upper-torso or lower-torso partial-body irradiation; however, TBI approximately doubled those plasma DNA levels at the same radiation dose. This technique therefore reflects total body cell damage. The advantages of this assay are that DNA extraction is not required, the assay is highly sensitive (0.002 ng), and results can be obtained within 2.5 hours after collection of plasma samples. Conclusions A radiation dose-dependent increase of plasma DNA was observed in the dose range from 2—10 Gy, suggesting that plasma DNA may be a useful radiation biomarker and adjunct to existing cell-based assays. PMID:19616745

  12. Electrical characterization of deep levels created by bombarding nitrogen-doped 4H-SiC with alpha-particle irradiation

    NASA Astrophysics Data System (ADS)

    Omotoso, Ezekiel; Meyer, Walter E.; Auret, F. Danie; Paradzah, Alexander T.; Legodi, Matshisa J.

    2016-03-01

    Deep-level transient spectroscopy (DLTS) and Laplace-DLTS were used to investigate the effect of alpha-particle irradiation on the electrical properties of nitrogen-doped 4H-SiC. The samples were bombarded with alpha-particles at room temperature (300 K) using an americium-241 (241Am) radionuclide source. DLTS revealed the presence of four deep levels in the as-grown samples, E0.09, E0.11, E0.16 and E0.65. After irradiation with a fluence of 4.1 × 1010 alpha-particles-cm-2, DLTS measurements indicated the presence of two new deep levels, E0.39 and E0.62 with energy levels, EC - 0.39 eV and EC - 0.62 eV, with an apparent capture cross sections of 2 × 10-16 and 2 × 10-14 cm2, respectively. Furthermore, irradiation with fluence of 8.9 × 1010 alpha-particles-cm-2 resulted in the disappearance of shallow defects due to a lowering of the Fermi level. These defects re-appeared after annealing at 300 °C for 20 min. Defects, E0.39 and E0.42 with close emission rates were attributed to silicon or carbon vacancy and could only be separated by using high resolution Laplace-DLTS. The DLTS peaks at EC - (0.55-0.70) eV (known as Z1/Z2) were attributed to an isolated carbon vacancy (VC).

  13. Microwave heating apparatus and method

    DOEpatents

    Johnson, Andrew J.; Petersen, Robert D.; Swanson, Stephen D.

    1990-01-01

    An apparatus is provided for heating and melting materials using microwave energy, and for permitting them to solidify. The apparatus includes a microwave energy source, a resonant cavity having an opening in its floor, a microwave energy choke encompassing the opening in the floor of the cavity, a metal container to hold the materials to be heated and melted, a turntable, and a lift-table. During operation, the combined action of the turntable and the lift-table position the metal container so that the top of the container is level with the floor of the cavity, is in substantial registration with the floor opening, and is encompassed by the microwave energy choke; thus, during operation, the interior of the container defines part of the resonant cavity. Additionally, a screw feeder, extending into the cavity and sheltered from microwave energy by a conveyor choke, may convey the materials to be heated to the container. Also, preferably, the floor of the resonant cavity may include perforatins, so that the offgases and dust generated in the apparatus may be removed from the resonant cavity by pulling outside air between the container choke and the exterior wall of the container into the resonant cavity and out from the cavity through the perforations.

  14. Mechanised flow system for on-line microwave digestion of food samples with off-line catalytic spectrophotometric determination of cobalt at ng l-1 levels.

    PubMed

    Pereira-Filho, E R; Arruda, M A

    1999-12-01

    A mechanised system for on-line slurry food sample digestion was developed and an off-line cobalt determination was performed. The stabilised slurry sample was introduced into an air carrier stream until reaching the digestion coils located inside a household microwave oven. Software written in Visual Basic 3.0 was developed to permit the transport of the slurry samples and the programming of the microwave oven and also the control of the mineralization valve. The proposed system was optimized for determination of cobalt in certified samples such as mussels, bovine liver and fish and also uncertified fish samples. The digestion parameters were established as 3 mol l-1 HNO3 for mussels, 3 mol l-1 HNO3 plus 0.16% v/v H2O2 for bovine liver and 12 mol l-1 HNO3 for fish employing maximum power for 5 min of microwave actuation. In the subsequent spectrophotometric method for the catalytic determination of cobalt, the Tiron and hydrogen peroxide concentrations were 1.8 x 10(-3) and 3.0 x 10(-4) mol l-1, respectively, and the sample residence time was 300 s as determined by an optimisation process. The proposed method features a linear range from 10 to 200 ng l-1 Co (r > 0.996) with detection and quantification limits of 1.7 and 5.5 ng l-1 Co, respectively. The precision, expressed as RSD, was 2.4% (n = 12) for repeatability and 5.2% (n = 10) for reproducibility and the accuracy of the proposed method was assessed by using certified samples and an alternative technique (ETAAS). PMID:10746313

  15. Flash microwave synthesis of trevorite nanoparticles

    SciTech Connect

    Bousquet-Berthelin, C. Chaumont, D.; Stuerga, D.

    2008-03-15

    Nickel ferrite nanoparticles have several possible applications as cathode materials for rechargeable batteries, named 'lithium-ion' batteries. In this study, NiFe{sub 2}O{sub 4} was prepared by microwave induced thermohydrolysis. The obtained nanoparticles were characterized by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), BET method, transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). All the results show that the microwave one-step flash synthesis leads in a very short time to NiFe{sub 2}O{sub 4} nanoparticles with elementary particles size close to 4-5 nm, and high specific surfaces (close to 240 m{sup 2}/g). Thus, microwave heating appears as an efficient source of energy to produce quickly nanoparticles with complex composition as ferrite. - Graphical abstract: At the end of the 20th century, a new concept of battery was introduced, named 'Li ion', where electrodes are both lithium-storage materials. Compounds with a spinel structure are so investigated and microwave heating appears as an efficient source of energy to produce nanoparticles in a very short time and at low temperature, with controlled size (4-5 nm) and high specific area (240 m{sup 2}/g). Legend: Pictogram represents our original microwave reactor, the RAMO (French acronym of Reacteur Autoclave Micro-Onde), containing the reactants and submitted to the microwave irradiation. Multicolor candy represents obtained material.

  16. Microwave Triggered Laser Ionization of Air

    NASA Astrophysics Data System (ADS)

    Vadiee, Ehsan; Prasad, Sarita; Jerald Buchenauer, C.; Schamiloglu, Edl

    2012-10-01

    The goal of this work is to study the evolution and dynamics of plasma expansion when a high power microwave (HPM) pulse is overlapped in time and space on a very small, localized region of plasma formed by a high energy laser pulse. The pulsed Nd:YAG laser (8 ns, 600mJ, repetition rate 10 Hz) is focused to generate plasma filaments in air with electron density of 10^17/cm^3. When irradiated with a high power microwave pulse these electrons would gain enough kinetic energy and further escalate avalanche ionization of air due to elastic electron-neutral collisions thereby causing an increased volumetric discharge region. An X-band relativistic backward wave oscillator(RBWO) at the Pulsed Power,Beams and Microwaves laboratory at UNM is constructed as the microwave source. The RBWO produces a microwave pulse of maximum power 400 MW, frequency of 10.1 GHz, and energy of 6.8 Joules. Special care is being given to synchronize the RBWO and the pulsed laser system in order to achieve a high degree of spatial and temporal overlap. A photodiode and a microwave waveguide detector will be used to ensure the overlap. Also, a new shadowgraph technique with a nanosecond time resolution will be used to detect changes in the shock wave fronts when the HPM signal overlaps the laser pulse in time and space.

  17. Fast calculations of the spectral diffuse-to-global ratios for approximating spectral irradiance at the street canyon level

    NASA Astrophysics Data System (ADS)

    Carrasco-Hernandez, Roberto; Smedley, Andrew R. D.; Webb, Ann R.

    2016-05-01

    Two radiative transfer models are presented that simplify calculations of street canyon spectral irradiances with minimum data input requirements, allowing better assessment of urban exposures than can be provided by standard unobstructed radiation measurements alone. Fast calculations improve the computational performance of radiation models, when numerous repetitions are required in time and location. The core of the models is the calculation of the spectral diffuse-to-global ratios (DGR) from an unobstructed global spectral measurement. The models are based on, and have been tested against, outcomes of the SMARTS2 algorithm (i.e. Simple Model of the Atmospheric Radiative Transfer of Sunshine). The modelled DGRs can then be used to partition global spectral irradiance values into their direct and diffuse components for different solar zenith angles. Finally, the effects of canyon obstructions can be evaluated independently on the direct and diffuse components, which are then recombined to give the total canyon irradiance. The first model allows ozone and aerosol inputs, while the second provides a further simplification, restricted to average ozone and aerosol contents but specifically designed for faster calculations. To assess the effect of obstructions and validate the calculations, a set of experiments with simulated obstructions (simulated canyons) were performed. The greatest source of uncertainty in the simplified calculations is in the treatment of diffuse radiation. The measurement-model agreement is therefore dependent on the region of the sky obscured and ranges from <5 % at all wavelengths to 20-40 % (wavelength dependent) when diffuse sky only is visible from the canyon.

  18. Multiphoton Microwave Ionization of Rydberg Atoms

    NASA Astrophysics Data System (ADS)

    Gurian, Joshua Houston

    This thesis describes a series of multiphoton microwave experiments on Rydberg atoms when the microwave frequency is much greater than the classical Kepler frequency of the excited atoms. A new kHz pulse repetition frequency dye laser system was constructed for Rydberg lithium excitation with a linewidth as narrow as 3 GHz. This new laser system is used for first experiments of multiphoton microwave ionization of Rydberg lithium approaching the photoionization limit using 17 and 36 GHz microwave pulses. A multi-channel quantum defect model is presented that well describes the experimental results, indicating that these results are due to the coherent coupling of many atomic levels both above and below the classical ionization limit. Finally, preliminary results of measuring the final-state distributions of high lying Rydberg states after 17 GHz microwave pulses are presented.

  19. Study on kinetic model of microwave thermocatalytic treatment of biomass tar model compound.

    PubMed

    Anis, Samsudin; Zainal, Z A

    2014-01-01

    Kinetic model parameters for toluene conversion under microwave thermocatalytic treatment were evaluated. The kinetic rate constants were determined using integral method based on experimental data and coupled with Arrhenius equation for obtaining the activation energies and pre-exponential factors. The model provides a good agreement with the experimental data. The kinetic model was also validated with standard error of 3% on average. The extrapolation of the model showed a reasonable trend to predict toluene conversion and product yield both in thermal and catalytic treatments. Under microwave irradiation, activation energy of toluene conversion was lower in the range of 3-27 kJ mol(-1) compared to those of conventional heating reported in the literatures. The overall reaction rate was six times higher compared to conventional heating. As a whole, the kinetic model works better for tar model removal in the absence of gas reforming within a level of reliability demonstrated in this study. PMID:24231266

  20. Effect of microwave irradiation on the resistance of Au-TiB{sub x}-Ge-Au-n-n{sup +}-n{sup ++}-GaAs(InP) ohmic contacts

    SciTech Connect

    Belyaev, A. E.; Sachenko, A. V.; Boltovets, N. S. Ivanov, V. N.; Konakova, R. V. Kudryk, Ya. Ya.; Matveeva, L. A.; Milenin, V. V.; Novitskii, S. V.; Sheremet, V. N.

    2012-04-15

    Temperature dependences of the contact resistivity {rho}{sub c} of Au-TiB{sub x}-Ge-Au-n-n{sup +}-n{sup ++}(GaAs)-InP ohmic contacts before and after short-term (10 s) microwave treatment have been studied both experimentally and theoretically. It is shown that {rho}{sub c} can decrease after microwave treatment in the entire temperature range of {rho}{sub c} measurements (100-400 K). Good agreement between the theoretical and experimental {rho}{sub c}(T) curves is attained and interpreted on the assumption that the dislocation density in the semiconductor near-surface region is varied as a result of microwave radiation.

  1. Microwave-induced local hyperthermia in combination with radiotherapy of human malignant tumors

    SciTech Connect

    U, R.; Noell, K.T.; Woodward, K.T.; Worde, B.T.; Fishburn, R.I.; Miller, L.S.

    1980-02-15

    Since 1976, two groups of patients have been treated with local microwave hyperthermia immediately following ionizing radiation. Group A patients had measurable multiple lesions assigned radiotherapy only, microwave hyperthermia only, or combined treatment. Ionizing radiation in 200 to 600 rad fractions was used 2 to 5 times per week to a total of 1800 to 4200 rad in 5 to 14 fractions. Group B patients had combination treatment only, with radiation fractions of 200 to 600 rad 2 to 5 times per week to a total of 200 to 4800 rad total in 6 to 20 fractions. Both groups received hyperthermia (42 to 44 C) 2 to 3 times per week, maximum ten sessions in four weeks. The 19 patients treated have had squamous cell carcinoma, adenocarcinoma, malignant melanoma, plasmacytoma, epithelioid sarcoma, and undifferentiated carcinoma. After more than 150 hyperthermia sessions, we find: (1) local hyperthermia with microwave alone or in combination with ionizing radiation can be used with excellent normal tissue tolerance provided local tissue temperatures are carefully monitored and controlled; (2) a higher level of heat induction in tumor tissue as compared to surrounding normal tissues; and (3) repeated hyperthermia at 42 to 43.5 C for 45 minutes per session immediately following photon irradiation yields a favorable therapeutic result, occasionally dramatic. Local microwave hyperthermia in combination withradiotherapy offers the possibility of substantial impact on clinical cancer therapy, whether of curative or palliative intent.

  2. Effect of high-power microwave on indicator bacteria for sterilization.

    PubMed

    Wu, Q

    1996-07-01

    According to the superiority sterilization, a specially-designed microwave disinfector using high-power microwave energy was made. A series of sterilizing experiments have been made to determine the effect of microwave energy on several typical indicator bacteria such as Bacillus subtilis var. niger, Bacillus stearothermophilus, Bacillus pumilus E601, Staphylococcus aureus, Bacillus cereus. Under the conditions of different sterilization duration and unequal intensity of microwave power irradiation onto the bacteria, a useful result of killing bacteria has been observed, i.e., the Bacillus subtilis can be considered as an optimum indicator bacterium for microwave sterilization. PMID:9216147

  3. Microwave Radiometer (MWR) Handbook

    SciTech Connect

    Morris, VR

    2006-08-01

    The Microwave Radiometer (MWR) provides time-series measurements of column-integrated amounts of water vapor and liquid water. The instrument itself is essentially a sensitive microwave receiver. That is, it is tuned to measure the microwave emissions of the vapor and liquid water molecules in the atmosphere at specific frequencies.

  4. Microwave Workshop for Windows.

    ERIC Educational Resources Information Center

    White, Colin

    1998-01-01

    "Microwave Workshop for Windows" consists of three programs that act as teaching aid and provide a circuit design utility within the field of microwave engineering. The first program is a computer representation of a graphical design tool; the second is an accurate visual and analytical representation of a microwave test bench; the third is a more…

  5. [Improvement on microwave technology of extracting polysaccharide from yacon leaves].

    PubMed

    Li, Jing-wei; Liu, Jian; Yang, Yong; Zheng, Ming-min; Rong, Ting-zhao

    2007-11-01

    According to the extraction ratio of polysaccharide in yacon leaves, the comparison between microwave extraction and traditional hot water extraction was conducted, and the two-factor and three-level experiment on the microwave extraction of polysaccharide from yacon leaves was investigated. The result showed that the extraction ratio of polysaccharide by using microwave extraction was better than that by using traditional hot water extraction. Moreover, according to the result of variance analysis and multiple comparison, the optimum conditions for extraction of polysaccharide by using microwave technology from yacon leaves were as follows: 280W microwave power for 2 times and 15 minutes at every time. PMID:18323219

  6. Wide power range microwave feedback controller

    NASA Technical Reports Server (NTRS)

    Titus, L. E. (Inventor)

    1978-01-01

    A substantially constant power level is derived over a predetermined frequency band, in each of a plurality of relatively widely spaced power ranges, from a microwave load having a predetermined amplitude versus frequency response, such as an antenna. A microwave source of substantially constant amplitude drives a forward path connected between the source and the load. A feedback path responsive to the microwave power level in the forward path derives a control voltage for the PIN attenuator. The equalizer attenuator drives a linear, crystal amplitude detector. Attenuating means included in the forward and feedback paths are selectively connected in circuit to maintain the power level of the microwave input to the amplitude detector substantially constant, even though different power ranges are supplied to the load by the forward path.

  7. The relationship between growth and soluble sugar concentration of Aloe vera plants grown under three levels of irradiance

    SciTech Connect

    Paez, A.; Gebre, G.M.; Tschaplinski, T.J. )

    1994-06-01

    The CAM plant Aloe vera was vegetatively propagated and grown under three irradiances: full sun, partial and deep shade (30% and 10% of ambient light, respectively) to determine the effect on growth, biomass allocation, and sugar concentration. After one year, the plants were harvested to determine final dry weight and the sugar concentration of the leaf mucilaginous gel. Plants grown under full sun produced twice the total dry weight of those grown under partial shade, with the difference equally partitioned between the shoot and root. Plants grown under full sun also produced thicker leaves, and more numerous and large auxiliary shoots. The dry weight of plants grown under deep shade was 8.6% that of plants grown under full sun, which was directly proportional to the irradiance received. Partial shade increased the number and length of leaves produced on the primary shoot, but the allocation of carbon to roots was the lowest of all treatments. Partial shade reduced the total sugar concentration of the leaf gel matrix to 34% that of plants under full sun, due to reductions in all sugars measured. Glucose was the most abundant soluble sugar, with its relative contribution to the total pool increasing under shade. In summary, the proportional effects of partial shading were greater on soluble sugar concentrations than on the total plant biomass produced.

  8. Localized Movement and Levels of 53BP1 Protein Are Changed by γ-irradiation in PML Deficient Cells.

    PubMed

    Legartová, Soňa; Sehnalová, Petra; Malyšková, Barbora; Küntziger, Thomas; Collas, Philippe; Cmarko, Dušan; Raška, Ivan; Sorokin, Dmitry V; Kozubek, Stanislav; Bártová, Eva

    2016-11-01

    We studied epigenetics, distribution pattern, kinetics, and diffusion of proteins recruited to spontaneous and γ-radiation-induced DNA lesions. We showed that PML deficiency leads to an increased number of DNA lesions, which was accompanied by changes in histone signature. In PML wt cells, we observed two mobile fractions of 53BP1 protein with distinct diffusion in spontaneous lesions. These protein fractions were not detected in PML-deficient cells, characterized by slow-diffusion of 53BP1. Single particle tracking analysis revealed limited local motion of 53BP1 foci in PML double null cells and local motion 53BP1 foci was even more reduced after γ-irradiation. However, radiation did not change co-localization between 53BP1 nuclear bodies and interchromatin granule-associated zones (IGAZs), nuclear speckles, or chromocenters. This newly observed interaction pattern imply that 53BP1 protein could be a part of not only DNA repair, but also process mediated via components accumulated in IGAZs, nuclear speckles, or paraspeckles. Together, PML deficiency affected local motion of 53BP1 nuclear bodies and changed composition and a number of irradiation-induced foci. J. Cell. Biochem. 117: 2583-2596, 2016. © 2016 Wiley Periodicals, Inc. PMID:27526954

  9. Implementation of SFQ Microwave Choppers for Controlling Quantum Bits

    NASA Astrophysics Data System (ADS)

    Miura, S.; Takeuchi, N.; Yamanashi, Y.; Yoshikawa, N.

    In order to control the state of qubits by a microwave pulse, the irradiation time and the amplitude have to be controlled precisely. We have developed a single-flux-quantum (SFQ) microwave chopper for high-speed switching of microwave pulses. The proposed chopper is composed of a DC/SFQ convertor, an SFQ switch, a PTL driver, and a superconducting low-pass filter (LPF). The chopper converts an input microwave, which is generated by an external microwave generator at the room temperature, into microwave pulses by using start/stop SFQ control signals. We designed and implemented a microwave chopper module, which can be attached to dilution refrigerators. SFQ chips were fabricated using the ISTEC 2.5 kA/cm2 Nb process. We tested the microwave chopper module at 4.2 K, and demonstrated that a 5-GHz microwave whose amplitude ranging from 0 μV to 150 μV can be chopped by the SFQ control signals.

  10. A new microwave EB accelerator for radiation processing

    NASA Astrophysics Data System (ADS)

    Cracknell, P. J.

    1995-02-01

    A new high beam power microwave electron linear accelerator, LINTEC 1020, has been built and installed for the AEA, EBIS (Harwell) Limited medical sterilisation irradiation facility. LINTEC microwave electron beam accelerator designs are based upon travelling wave RF structures working at 1300 MHz, with beam powers from 10 to 45 k Watts at 5 to 12 MeV. The accelerator design, installation and operating details are described together with performance characteristics of alternative equipments.

  11. Applicability of microwave-assisted extraction combined with LC-MS/MS in the evaluation of booster biocide levels in harbour sediments.

    PubMed

    Sánchez-Rodríguez, Alvaro; Sosa-Ferrera, Zoraida; Santana-Rodríguez, José Juan

    2011-01-01

    A new sample treatment method for the determination of four common booster biocides (Diuron, TCMTB, Irgarol 1051 and Dichlofluanid) in harbour sediment samples has been developed that uses liquid chromatography-tandem mass spectrometry (LC-MS/MS) after microwave-assisted extraction, followed by clean-up and a solid phase extraction preconcentration step (MAE-SPE). The effects of different variables on MAE-SPE were studied. The recoveries obtained were greater than 75%, and the relative standard deviation was less than 7%. The detection limits ranged between 0.1 and 0.3 ng g⁻¹. The developed methodology was successfully applied to the evaluation of the presence of booster biocides in sediment samples from different harbours and marinas of Gran Canaria Island (Canary Islands, Spain). PMID:20947123

  12. Medical applications of microwaves

    NASA Astrophysics Data System (ADS)

    Vrba, Jan; Lapes, M.

    2004-04-01

    Medical applications of microwaves (i.e. a possibility to use microwave energy and/or microwave technique and technology for therapeutical purposes) are a quite new and a very rapidly developing field. Microwave thermotherapy is being used in medicine for the cancer treatment and treatment of some other diseases since early eighties. In this contribution we would like to offer general overview of present activities in the Czech Republic, i.e. clinical applications and results, technical aspects of thermo therapeutic equipment and last but not least, prospective diagnostics based on microwave principals ant technology and instrumentation.

  13. Microwave sintering of ceramics

    SciTech Connect

    Snyder, W.B.

    1989-01-01

    Successful adaptation of microwave heating to the densification of ceramic materials require a marriage of microwave and materials technologies. Using an interdisciplinary team of microwave and materials engineers, we have successfully demonstrated the ability to density ceramic materials over a wide range of temperatures. Microstructural evolution during microwave sintering has been found to be significantly different from that observed in conventional sintering. Our results and those of others indicate that microwave sintering has the potential to fabricate components to near net shape with mechanical properties equivalent to hot pressed or hot isostatically pressed material. 6 refs., 11 figs.

  14. Immunolocalization of MAP-2 in routinely formalin-fixed, paraffin-embedded guinea pig brain sections using microwave irradiation: a comparison of different combinations of antibody clones and antigen retrieval buffer solutions.

    PubMed

    Kan, Robert K; Pleva, Christina M; Hamilton, Tracey A; Petrali, John P

    2005-04-01

    The present study was designed to evaluate the efficacy of different microwave pretreatment methods to retrieve microtubule-associated protein 2 (MAP-2) immunoreactivity in formalin-fixed, paraffin-embedded guinea pig brain sections. Brain sections, microwave pretreated in boiling sodium citrate, citric acid, Tris hydrochloride, and EDTA buffers of pH 4, 6, and 8, were labeled with four different clones of MAP-2 monoclonal antibodies. No MAP-2 immunoreactivity was observed in control sections processed without microwave pretreatment. Optimal MAP-2 immunoreactivity was observed only when MAP-2 antibody clone AP18 was used in conjunction with citric acid buffer of pH 6.0. Using this combination, brain sections from nerve agent soman-exposed guinea pigs were found to exhibit marked reduction in MAP-2 immunostaining in the hippocampus. These observations suggest that the clone of the antibody in addition to the type and pH of antigen retrieval (AR) solution are important variables to be considered for establishing an optimal AR technique. When studying counterpart antigens of species other than that to which the antibodies were originally raised, different antibody clones must be tested in combination with different microwave-assisted AR (MAR) methods. This MAR method makes it possible to conduct retrospective studies on archival guinea pig brain paraffin blocks to evaluate changes in neuronal MAP-2 expression as a consequence of chemical warfare nerve agent toxicity. PMID:15817147

  15. Microwave effects on isolated chick embryo hearts

    SciTech Connect

    Caddemi, A.; Tamburello, C.C.; Zanforlin, L.; Torregrossa, M.V.

    1986-01-01

    This study was designed to examine the effects of microwaves on the electric activity of hearts as a means of elucidating interactive mechanisms of nonionizing radiation with cardiac tissue. Experiments were performed on isolated hearts of 9-12-day-old chick embryos placed in small petri dishes. Oxygenated isotonic Ringer's solution at 37 degrees C permitted heart survival. Samples were irradiated at 2.45 GHz with a power density of 3 mW/cm2. The heart signal was detected with a glass micropipet inserted into the sinoatrial node and examined by means of a Berg-Fourier analyzer. Pulsed microwaves caused the locking of the heartbeat to the modulation frequency, whereas continuous wave irradiation might have induced slight bradycardia. Pulsed fields induced stimulation or regularization of the heartbeat in arrhythmia, fibrillation, or arrest of the heart.

  16. High brightness microwave lamp

    DOEpatents

    Kirkpatrick, Douglas A.; Dolan, James T.; MacLennan, Donald A.; Turner, Brian P.; Simpson, James E.

    2003-09-09

    An electrodeless microwave discharge lamp includes a source of microwave energy, a microwave cavity, a structure configured to transmit the microwave energy from the source to the microwave cavity, a bulb disposed within the microwave cavity, the bulb including a discharge forming fill which emits light when excited by the microwave energy, and a reflector disposed within the microwave cavity, wherein the reflector defines a reflective cavity which encompasses the bulb within its volume and has an inside surface area which is sufficiently less than an inside surface area of the microwave cavity. A portion of the reflector may define a light emitting aperture which extends from a position closely spaced to the bulb to a light transmissive end of the microwave cavity. Preferably, at least a portion of the reflector is spaced from a wall of the microwave cavity. The lamp may be substantially sealed from environmental contamination. The cavity may include a dielectric material is a sufficient amount to require a reduction in the size of the cavity to support the desired resonant mode.

  17. Microwave-assisted regeneration of activated carbon.

    PubMed

    Foo, K Y; Hameed, B H

    2012-09-01

    Microwave heating was used in the regeneration of methylene blue-loaded activated carbons produced from fibers (PFAC), empty fruit bunches (EFBAC) and shell (PSAC) of oil palm. The dye-loaded carbons were treated in a modified conventional microwave oven operated at 2450 MHz and irradiation time of 2, 3 and 5 min. The virgin properties of the origin and regenerated activated carbons were characterized by pore structural analysis and nitrogen adsorption isotherm. The surface chemistry was examined by zeta potential measurement and determination of surface acidity/basicity, while the adsorptive property was quantified using methylene blue (MB). Microwave irradiation preserved the pore structure, original active sites and adsorption capacity of the regenerated activated carbons. The carbon yield and the monolayer adsorption capacities for MB were maintained at 68.35-82.84% and 154.65-195.22 mg/g, even after five adsorption-regeneration cycles. The findings revealed the potential of microwave heating for regeneration of spent activated carbons. PMID:22728787

  18. Microwave hemorrhagic stroke detector

    DOEpatents

    Haddad, Waleed S.; Trebes, James E.

    2007-06-05

    The microwave hemorrhagic stroke detector includes a low power pulsed microwave transmitter with a broad-band antenna for producing a directional beam of microwaves, an index of refraction matching cap placed over the patients head, and an array of broad-band microwave receivers with collection antennae. The system of microwave transmitter and receivers are scanned around, and can also be positioned up and down the axis of the patients head. The microwave hemorrhagic stroke detector is a completely non-invasive device designed to detect and localize blood pooling and clots or to measure blood flow within the head or body. The device is based on low power pulsed microwave technology combined with specialized antennas and tomographic methods. The system can be used for rapid, non-invasive detection of blood pooling such as occurs with hemorrhagic stoke in human or animal patients as well as for the detection of hemorrhage within a patient's body.

  19. Microwave hemorrhagic stroke detector

    DOEpatents

    Haddad, Waleed S.; Trebes, James E.

    2002-01-01

    The microwave hemorrhagic stroke detector includes a low power pulsed microwave transmitter with a broad-band antenna for producing a directional beam of microwaves, an index of refraction matching cap placed over the patients head, and an array of broad-band microwave receivers with collection antennae. The system of microwave transmitter and receivers are scanned around, and can also be positioned up and down the axis of the patients head. The microwave hemorrhagic stroke detector is a completely non-invasive device designed to detect and localize blood pooling and clots or to measure blood flow within the head or body. The device is based on low power pulsed microwave technology combined with specialized antennas and tomographic methods. The system can be used for rapid, non-invasive detection of blood pooling such as occurs with hemorrhagic stroke in human or animal patients as well as for the detection of hemorrhage within a patient's body.

  20. Laser-induced microwave generation with nonlinear optical crystals

    NASA Astrophysics Data System (ADS)

    Borghesani, Francesco; Braggio, Caterina; Carugno, Giovanni; Della Valle, Federico; Ruoso, Giuseppe

    2014-05-01

    We report about a novel technique to generate microwave radiation by the irradiation of a nonlinear optical crystal with uniformly spaced, ultrashort optical pulses delivered by a mode-locked laser. We study systematically the laser polarization and intensity dependence of the microwave signal to conclusively show that it is a nonlinear phenomenon and that it originates from optical rectification. The measurements have been conducted using KTP, LBO and ZnSe crystals. The observed pulsed microwave signals are harmonically related to the laser pulses repetition rate, a feature that can be exploited to develop an innovative ultrafast laser detector.

  1. Mitigating the Effects of Xuebijing Injection on Hematopoietic Cell Injury Induced by Total Body Irradiation with γ rays by Decreasing Reactive Oxygen Species Levels

    PubMed Central

    Li, Deguan; Lu, Lu; Zhang, Junling; Wang, Xiaochun; Xing, Yonghua; Wu, Hongying; Yang, Xiangdong; Shi, Zhexin; Zhao, Mingfeng; Fan, Saijun; Meng, Aimin

    2014-01-01

    Hematopoietic injury is the most common side effect of radiotherapy. However, the methods available for the mitigating of radiation injury remain limited. Xuebijing injection (XBJ) is a traditional Chinese medicine used to treat sepsis in the clinic. In this study, we investigated the effects of XBJ on the survival rate in mice with hematopoietic injury induced by γ ray ionizing radiation (IR). Mice were intraperitoneally injected with XBJ daily for seven days after total body irradiation (TBI). Our results showed that XBJ (0.4 mL/kg) significantly increased 30-day survival rates in mice exposed to 7.5 Gy TBI. This effect may be attributable to improved preservation of white blood cells (WBCs) and hematopoietic cells, given that bone marrow (BM) cells from XBJ-treated mice produced more granulocyte-macrophage colony forming units (CFU-GM) than that in the 2 Gy/TBI group. XBJ also decreased the levels of reactive oxygen species (ROS) by increasing glutathione (GSH) and superoxide dismutase (SOD) levels in serum and attenuated the increased BM cell apoptosis caused by 2 Gy/TBI. In conclusion, these findings suggest that XBJ enhances the survival rate of irradiated mice and attenuates the effects of radiation on hematopoietic injury by decreasing ROS production in BM cells, indicating that XBJ may be a promising therapeutic candidate for reducing hematopoietic radiation injury. PMID:24927144

  2. Proton irradiation effects on deep level states in Mg-doped p-type GaN grown by ammonia-based molecular beam epitaxy

    SciTech Connect

    Zhang, Z.; Arehart, A. R.; Ringel, S. A.; Kyle, E. C. H.; Speck, J. S.; Chen, J.; Zhang, E. X.; Fleetwood, D. M.; Schrimpf, R. D.

    2015-01-12

    The impact of proton irradiation on the deep level states throughout the Mg-doped p-type GaN bandgap is investigated using deep level transient and optical spectroscopies. Exposure to 1.8 MeV protons of 1 × 10{sup 13 }cm{sup −2} and 3 × 10{sup 13 }cm{sup −2} fluences not only introduces a trap with an E{sub V} + 1.02 eV activation energy but also brings monotonic increases in concentration for as-grown deep states at E{sub V} + 0.48 eV, E{sub V} + 2.42 eV, E{sub V} + 3.00 eV, and E{sub V} + 3.28 eV. The non-uniform sensitivities for individual states suggest different physical sources and/or defect generation mechanisms. Comparing with prior theoretical calculations reveals that several traps are consistent with associations to nitrogen vacancy, nitrogen interstitial, and gallium vacancy origins, and thus are likely generated through displacing nitrogen and gallium atoms from the crystal lattice in proton irradiation environment.

  3. Space-resolved keV spectroscopy study of neonlike x-ray laser plasmas created with low-level prepulse irradiation

    NASA Astrophysics Data System (ADS)

    Nantel, Marc; Klisnick, Annie; Jamelot, Gerard; Holden, P. B.; Jaegle, Pierre; Zeitoun, Philippe; Tallents, Gregory J.; MacPhee, Andrew G.; Lewis, Ciaran L. S.

    1995-09-01

    Through the use of time-integrated space-resolved keV spectroscopy, we investigate line plasmas showing gain for irradiation using the prepulse technique. The experiments were conducted with the LULI laser of the Ecole Polytechnique, Palaiseau, France), at 1.06 micrometer with prepulse-to-main pulse intensity ratio ranging from 10-6 to 10-2. The particular x-ray lasers which were studied were the collisionally excited Ne-like zinc, copper and nickel systems. The effect of the prepulses on plasma conditions are inferred through spectroscopic line ratio diagnostics. It is observed that the value of the electron temperature for each system does not vary significantly with prepulse levels, nor does their spatially resolved profile along the line. The lateral width and density of the Ne-like regions in the plasmas of all three x-ray lasers are seen to increase with the prepulse level.

  4. Microwave Treatment for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Hernandez-Moya, Sonia

    2009-01-01

    NASA seeks to transfer the NASA developed microwave ablation technology, designed for the treatment of ventricular tachycardia (irregular heart beat), to industry. After a heart attack, many cells surrounding the resulting scar continue to live but are abnormal electrically; they may conduct impulses unusually slowly or fire when they would typically be silent. These diseased areas might disturb smooth signaling by forming a reentrant circuit in the muscle. The objective of microwave ablation is to heat and kill these diseased cells to restore appropriate electrical activity in the heart. This technology is a method and apparatus that provides for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In comparison with other methods that involve direct-current pulses or radio frequencies below 1 GHz, this method may prove more effective in treating ventricular tachycardia. This is because the present method provides for greater control of the location, cross-sectional area, and depth of a lesion via selection of the location and design of the antenna and the choice of microwave power and frequency.

  5. Microwave Treatment for Cardiac Arrhythmias

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Raffoul, George W. (Inventor); Pacifico, Antonio (Inventor)

    1999-01-01

    Method and apparatus are provided for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue to treat ventricular tachycardia and other arrhythmias while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In operation, microwave energy between about 1 Gigahertz and 12 Gigahertz is applied to monopole microwave radiator having a surface wave limiter. A test setup provides physical testing of microwave radiators to determine the temperature profile created in actual heart tissue or ersatz heart tissue. Saline solution pumped over the heart tissue with a peristaltic pump simulates blood flow. Optical temperature sensors disposed at various tissue depths within the heart tissue detect the temperature profile without creating any electromagnetic interference. The method may be used to produce a desired temperature profile in other body tissues reachable by catheter such as tumors and the like.

  6. Transcatheter Antenna For Microwave Treatment

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Carl, James R. (Inventor); Raffoul, George W. (Inventor); Karasack, Vincent G. (Inventor); Pacifico, Antonio (Inventor); Pieper, Carl F. (Inventor)

    2000-01-01

    Method and apparatus are provided for propagating microwave energy into heart tissues to produce a desired temperature profile therein at tissue depths sufficient for thermally ablating arrhythmogenic cardiac tissue to treat ventricular tachycardia and other arrhythmias while preventing excessive heating of surrounding tissues, organs, and blood. A wide bandwidth double-disk antenna is effective for this purpose over a bandwidth of about six gigahertz. A computer simulation provides initial screening capabilities for an antenna such as antenna, frequency, power level, and power application duration. The simulation also allows optimization of techniques for specific patients or conditions. In operation, microwave energy between about 1 Gigahertz and 12 Gigahertz is applied to monopole microwave radiation having a surface wave limiter. A test setup provides physical testing of microwave radiators to determine the temperature profile created in actual heart tissue or ersatz heart tissue. Saline solution pumped over the heart tissue with a peristaltic pump simulates blood flow. Optical temperature sensors disposed at various tissue depths within the heart tissue detect the temperature profile without creating any electromagnetic interference. The method may he used to produce a desired temperature profile in other body tissues reachable by catheter such as tumors and the like.

  7. Microwave Effect for Glycosylation Promoted by Solid Super Acid in Supercritical Carbon Dioxide

    PubMed Central

    Hinou, Hiroshi; Saito, Naohiro; Ogawa, Masato; Maeda, Takahiko; Nishimura, Shin-Ichiro

    2009-01-01

    The effects of microwave irradiation (2.45 GHz, 200 W) on glycosylation promoted by a solid super acid in supercritical carbon dioxide was investigated with particular attention paid to the structure of the acceptor substrate. Because of the symmetrical structure and high diffusive property of supercritical carbon dioxide, microwave irradiation did not alter the temperature of the reaction solution, but enhanced reaction yield when aliphatic acceptors are employed. Interestingly, the use of a phenolic acceptor under the same reaction conditions did not show these promoting effects due to microwave irradiation. In the case of aliphatic diol acceptors, the yield seemed to be dependent on the symmetrical properties of the acceptors. The results suggest that microwave irradiation do not affect the reactivity of the donor nor promoter independently. We conclude that the effect of acceptor structure on glycosylation yield is due to electric delocalization of hydroxyl group and dielectrically symmetric structure of whole molecule. PMID:20054471

  8. Microwave-mediated selective monotetrahydropyranylation of symmetrical diols catalyzed by iodine.

    PubMed

    Deka, N; Sarma, J C

    2001-03-23

    Selective protection of one hydroxyl group as its tetrahydropyranyl ether in 1,n-symmetrical diol is achieved by iodine-catalyzed reaction of the diol with dihydropyranyl ether under microwave irradiation. PMID:11300886

  9. Multilayered Graphene in Microwaves

    NASA Astrophysics Data System (ADS)

    Kuzhir, P.; Volynets, N.; Maksimenko, S.; Kaplas, T.; Svirko, Yu.

    2013-05-01

    We report on the experimental study of electromagnetic (EM) properties of multilayered graphene in Ka-band synthesized by catalytic chemical vapor deposition (CVD) process in between nanometrically thin Cu catalyst film and dielectric (SiO2) substrate. The quality of the produced multilayered graphene samples were monitored by Raman spectroscopy. The thickness of graphene films was controlled by atomic force microscopy (AFM) and was found to be a few nanometers (up to 5 nm). We discovered, that the fabricated graphene provided remarkably high EM shielding efficiency caused by absorption losses at the level of 35-43% of incident power. Being highly conductive at room temperature, multi-layer graphene emerges as a promising material for manufacturing ultrathin microwave coatings to be used in aerospace applications.

  10. Microwave-assisted synthesis of sensitive silver substrate for surface-enhanced Raman scattering spectroscopy.

    PubMed

    Xia, Lixin; Wang, Haibo; Wang, Jian; Gong, Ke; Jia, Yi; Zhang, Huili; Sun, Mengtao

    2008-10-01

    A sensitive silver substrate for surface-enhanced Raman scattering (SERS) spectroscopy is synthesized under multimode microwave irradiation. The microwave-assisted synthesis of the SERS-active substrate was carried out in a modified domestic microwave oven of 2450 MHz, and the reductive reaction was conducted in a polypropylene container under microwave irradiation with a power of 100 W for 5 min. Formaldehyde was employed as both the reductant and microwave absorber in the reductive process. The effects of different heating methods (microwave dielectric and conventional) on the properties of the SERS-active substrates were investigated. Samples obtained with 5 min of microwave irradiation at a power of 100 W have more well-defined edges, corners, and sharper surface features, while the samples synthesized with 1 h of conventional heating at 40 degrees C consist primarily of spheroidal nanoparticles. The SERS peak intensity of the approximately 1593 cm(-1) band of 4-mercaptobenzoic acid adsorbed on silver nanoparticles synthesized with 5 min of microwave irradiation at a power of 100 W is about 30 times greater than when it is adsorbed on samples synthesized with 1 h of conventional heating at 40 degrees C. The results of quantum chemical calculations are in good agreement with our experimental data. This method is expected to be utilized for the synthesis of other metal nanostructural materials. PMID:19045112

  11. Microwave-assisted synthesis of sensitive silver substrate for surface-enhanced Raman scattering spectroscopy

    NASA Astrophysics Data System (ADS)

    Xia, Lixin; Wang, Haibo; Wang, Jian; Gong, Ke; Jia, Yi; Zhang, Huili; Sun, Mengtao

    2008-10-01

    A sensitive silver substrate for surface-enhanced Raman scattering (SERS) spectroscopy is synthesized under multimode microwave irradiation. The microwave-assisted synthesis of the SERS-active substrate was carried out in a modified domestic microwave oven of 2450MHz, and the reductive reaction was conducted in a polypropylene container under microwave irradiation with a power of 100W for 5min. Formaldehyde was employed as both the reductant and microwave absorber in the reductive process. The effects of different heating methods (microwave dielectric and conventional) on the properties of the SERS-active substrates were investigated. Samples obtained with 5min of microwave irradiation at a power of 100W have more well-defined edges, corners, and sharper surface features, while the samples synthesized with 1h of conventional heating at 40°C consist primarily of spheroidal nanoparticles. The SERS peak intensity of the ˜1593cm-1 band of 4-mercaptobenzoic acid adsorbed on silver nanoparticles synthesized with 5min of microwave irradiation at a power of 100W is about 30 times greater than when it is adsorbed on samples synthesized with 1h of conventional heating at 40°C. The results of quantum chemical calculations are in good agreement with our experimental data. This method is expected to be utilized for the synthesis of other metal nanostructural materials.

  12. RESPONSES OF AIRBORNE BIOTA TO MICROWAVE TRANSMISSION FROM SATELLITE POWER SYSTEM (SPS)

    EPA Science Inventory

    The goal of this program is to determine whether microwave irradiation adversely alters a wide-range of complex avian behavior modes that are essential to their survival. Effects of microwaves (2.45 GHz) have been studied extensively in mammalian species, e.g., rats, mice, rabbit...

  13. Microwave-assisted synthesis of sensitive silver substrate for surface-enhanced Raman scattering spectroscopy

    SciTech Connect

    Xia Lixin; Wang Haibo; Wang Jian; Gong Ke; Jia Yi; Zhang Huili; Sun Mengtao

    2008-10-07

    A sensitive silver substrate for surface-enhanced Raman scattering (SERS) spectroscopy is synthesized under multimode microwave irradiation. The microwave-assisted synthesis of the SERS-active substrate was carried out in a modified domestic microwave oven of 2450 MHz, and the reductive reaction was conducted in a polypropylene container under microwave irradiation with a power of 100 W for 5 min. Formaldehyde was employed as both the reductant and microwave absorber in the reductive process. The effects of different heating methods (microwave dielectric and conventional) on the properties of the SERS-active substrates were investigated. Samples obtained with 5 min of microwave irradiation at a power of 100 W have more well-defined edges, corners, and sharper surface features, while the samples synthesized with 1 h of conventional heating at 40 deg. C consist primarily of spheroidal nanoparticles. The SERS peak intensity of the {approx}1593 cm{sup -1} band of 4-mercaptobenzoic acid adsorbed on silver nanoparticles synthesized with 5 min of microwave irradiation at a power of 100 W is about 30 times greater than when it is adsorbed on samples synthesized with 1 h of conventional heating at 40 deg. C. The results of quantum chemical calculations are in good agreement with our experimental data. This method is expected to be utilized for the synthesis of other metal nanostructural materials.

  14. MICROWAVE-ASSISTED SYNTHESIS OF NOBLE NANOSTRUCTURES USING BIODEGRADABLE POLYMER CARBOXYMETHYL CELLULOSE

    EPA Science Inventory

    Microwave-assisted synthesis of noble nanostructures (Au, Pt, and Pd) using biodegradable polymer carboxymethyl cellulose (CMC) under microwave irradiation (MW) at 100 0C is reported. The reaction occurs within a few minutes, whereas at room temperature the reaction does not pro...

  15. Acclimation of Trichodesmium erythraeum ISM101 to high and low irradiance analysed on the physiological, biophysical and biochemical level.

    PubMed

    Andresen, Elisa; Lohscheider, Jens; Setlikova, Eva; Adamska, Iwona; Simek, Miloslav; Küpper, Hendrik

    2010-01-01

    As the nonheterocystous diazotrophic cyanobacterium Trichodesmium lives both at the ocean surface and deep in the water column, it has to acclimate to vastly different irradiances. Here, we investigate its strategy of light acclimation in several ways. In this study, we used spectrally resolved fluorescence kinetic microscopy to investigate the biophysics of photosynthesis in individual cells, analysed cell extracts for pigment and phycobiliprotein composition, measured nitrogenase activity and the abundance of key proteins, and assayed protein synthesis/degradation by radioactive labelling. After acclimation to high light, Trichodesmium grew faster at 1000 micromol m(-2) s(-1) than at 100 micromol m(-2) s(-1). This acclimation was associated with decreasing cell diameter, faster protein turnover, the down-regulation of light-harvesting pigments and the outer part of the phycobiliprotein antenna, the up-regulation of light-protective carotenoids, changes in the coupling of phycobilisomes to the reaction centres and in the coupling of individual phycobiliproteins to the phycobilisomes. The latter was particularly interesting, as it represents an as yet unreported light acclimation strategy. Only in the low light-acclimated culture and only after the onset of actinic light did phycourobilin and phycoerythrin contribute to photochemical fluorescence quenching, showing that these phycobiliproteins may become quickly (in seconds) very closely coupled to photosystem II. This fast reversible coupling also became visible in the nonphotochemical changes of the fluorescence quantum yield. PMID:19863729

  16. Industrial scale microwave processing of tomato juice using a novel continuous microwave system.

    PubMed

    Stratakos, Alexandros Ch; Delgado-Pando, Gonzalo; Linton, Mark; Patterson, Margaret F; Koidis, Anastasios

    2016-01-01

    This study evaluated the effect of an industrial scale continuous flow microwave volumetric heating system in comparison to conventional commercial scale pasteurisation for the processing of tomato juice in terms of physicochemical properties, microbial characteristics and antioxidant capacity. The effect against oxidative stress in Caco-2 cells, after in vitro digestion was also investigated. Physicochemical and colour characteristics of juices were very similar between technologies and during storage. Both conventional and microwave pasteurisation inactivated microorganisms and kept them in low levels throughout storage. ABTS[Symbol: see text](+) values, but not ORAC, were higher for the microwave pasteurised juice at day 0 however no significant differences between juices were observed during storage. Juice processed with the microwave system showed an increased cytoprotective effect against H2O2 induced oxidation in Caco-2 cells. Organoleptic analysis revealed that the two tomato juices were very similar. The continuous microwave volumetric heating system appears to be a viable alternative to conventional pasteurisation. PMID:26213019

  17. Automated Microwave Frequency Control in Dynamic Nuclear Polarization Experiments

    NASA Astrophysics Data System (ADS)

    Scott, Ethan; Johnson, Ian; Keller, Dustin; Solid Polarized Target Group Team

    2016-03-01

    To achieve highest polarization levels in dynamic nuclear polarization (DNP) experiments, target materials must be subjected to microwave irradiation at a particular frequency determined by the difference in the nuclear Larmor and electron paramagnetic resonance (EPR) frequencies. However, this resonant frequency is variable; it drifts as a result of radiation damage. Manually adjusting the frequency to accommodate for this fluctuation can be difficult, and improper adjustments negatively impact the polarization. In response to this problem, a controller has been developed which automates the process of seeking and maintaining optimal frequency. The creation of such a controller has necessitated research into the correlation between microwave frequency and corresponding polarization growth or decay rates in DNP experiments. Knowledge gained from the research of this unique relationship has additionally lead to the development of a Monte-Carlo simulation which accurately models polarization as a function of frequency and a number of other parameters. The simulation and controller continue to be refined, however, recent DNP experimentation has confirmed the controller's effectiveness.

  18. Coupled microwave/photoassisted methods for environmental remediation.

    PubMed

    Horikoshi, Satoshi; Serpone, Nick

    2014-01-01

    The microwave-induced acceleration of photocatalytic reactions was discovered serendipitously in the late 1990s. The activity of photocatalysts is enhanced significantly by both microwave radiation and UV light. Particularly relevant, other than as a heat source, was the enigmatic phenomenon of the non-thermal effect(s) of the microwave radiation that facilitated photocatalyzed reactions, as evidenced when examining various model contaminants in aqueous media. Results led to an examination of the possible mechanism(s) of the microwave effect(s). In the present article we contend that the microwaves' non-thermal effect(s) is an important factor in the enhancement of TiO2-photoassisted reactions involving the decomposition of organic pollutants in model wastewaters by an integrated (coupled) microwave-/UV-illumination method (UV/MW). Moreover, such coupling of no less than two irradiation methods led to the fabrication and ultimate investigation of microwave discharged electrodeless lamps (MDELs) as optimal light sources; their use is also described. The review focuses on the enhanced activity of photocatalytic reactions when subjected to microwave radiation and concentrates on the authors' research of the past few years. PMID:25379646

  19. Microwave Lightcraft concept

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Looking like an alien space ship or a flying saucer the Microwave Lightcraft is an unconventional launch vehicle approach for delivering payload to orbit using power transmitted via microwaves. Microwaves re beamed from either a ground station or an orbiting solar power satellite to the lightcraft. The energy received breaks air molecules into a plasma and a magnetohydrodynamic fanjet provides the lifting force. Only a small amount of propellant is required for circulation, attitude control and deorbit.

  20. Enhanced Microwave Hyperthermia of Cancer Cells with Fullerene.

    PubMed

    Sun, Mingrui; Kiourti, Asimina; Wang, Hai; Zhao, Shuting; Zhao, Gang; Lu, Xiongbin; Volakis, John L; He, Xiaoming

    2016-07-01

    Hyperthermia generated with various energy sources including microwave has been widely studied for cancer treatment. However, the potential damage due to nontargeted heating of normal tissue is a major hurdle to its widespread application. Fullerene is a potential agent for improving cancer therapy with microwave hyperthermia but is limited by its poor solubility in water for biomedical applications. Here we report a combination therapy for enhanced cancer cell destruction by combining microwave heating with C60-PCNPs consisting of fullerene (C60) encapsulated in Pluronic F127-chitosan nanoparticles (PCNPs) with high water solubility. A cell culture dish integrated with an antenna was fabricated to generate microwave (2.7 GHz) for heating PC-3 human prostate cancer cells either with or without the C60-PCNPs. The cell viability data show that the C60-PCNPs alone have minimal cytotoxicity. The combination of microwave heating and C60-PCNPs is significantly more effective than the microwave heating alone in killing the cancer cells (7.5 versus 42.2% cell survival). Moreover, the combination of microwave heating and C60-PCNPs is significantly more destructive to the cancer cells than the combination of simple water-bath heating (with a similar thermal history to microwave heating) and C60-PCNPs (7.5 versus 32.5% survival) because the C60 in the many nanoparticles taken up by the cells can absorb the microwave energy and convert it into heat to enhance heating inside the cells under microwave irradiation. These data suggest the great potential of targeted heating via fullerene for enhanced cancer treatment by microwave hyperthermia. PMID:27195904