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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. 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.

  4. SOLVENT FREE CHEMICAL TRANSFORMATION USING MICROWAVE IRRADIATION

    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 mineral oxides. Recent developments will be presented on the synthetic utility o...

  5. 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.

  6. 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.

  7. 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

  8. Effects of microwave power and microwave irradiation time on pretreatment efficiency and characteristics of corn stover using combination of steam explosion and microwave irradiation (SE-MI) pretreatment.

    PubMed

    Pang, Feng; Xue, Shulin; Yu, Shengshuan; Zhang, Chao; Li, Bing; Kang, Yong

    2012-08-01

    The effects of microwave power and microwave irradiation time on pretreatment efficiency and characteristics of corn stover were investigated based on a new process named combination of steam explosion and microwave irradiation (SE-MI) pretreatment. Results showed that with microwave power and microwave irradiation time increasing, glucose and xylose that released into hydrolyzate, as well as enzymatic hydrolysis yields and sugar yields of glucose and xylose were all slightly increased after SE-MI pretreatment. The maximum sugar yield was 72.1 g per 100 g glucose and xylose in feedstock, achieved at 540 W microwave power and 5 min microwave irradiation time. XRD analysis showed that the crystallinity of biomass was 15.6-19.9% lower for SE-MI pretreatment with microwave effect than that without microwave effect. However, low microwave power and short microwave irradiation time were favorable for SE-MI pretreatment considering energy consumption.

  9. Constant-dose microwave irradiation of insect pupae

    NASA Astrophysics Data System (ADS)

    Olsen, Richard G.

    Pupae of the yellow mealworm Tenebrio molitor L. were subjected to microwave irradiation for 1.5-24 hours at power density levels adjusted to produce a total dosage of approximately 1123 J/g in each insect for every experiment. Insects without visible blemishes were exposed in a standing wave irradiation system such that half of them were exposed in the plane of maximum electric field (E field) and the other half were exposed in the plane of maximum magnetic field (H field). Both E field and H field insects exhibited nearly the same specific absorption rate (SAR) for pupal orientation parallel to the magnetic field vector at 5.95 GHz. Irradiations were conducted both with and without the use of a ventilating fan to control the temperature rise in the irradiation chamber. Abnormal development as a result of the microwave exposure was seen only in the high-power, short-duration experiment without chamber ventilation. This result suggests a thermal interaction mechanism for explanation of observed microwave-induced abnormalities. A study of the time course of the average temperature rise in the irradiated insects indicates that teratological effects for this configuration have a temperature threshold of approximately 40°C.

  10. [Application of microwave irradiation technology to the field of pharmaceutics].

    PubMed

    Zhang, Xue-Bing; Shi, Nian-Qiu; Yang, Zhi-Qiang; Wang, Xing-Lin

    2014-03-01

    Microwaves can be directly transformed into heat inside materials because of their ability of penetrating into any substance. The degree that materials are heated depends on their dielectric properties. Materials with high dielectric loss are more easily to reach a resonant state by microwaves field, then microwaves can be absorbed efficiently. Microwave irradiation technique with the unique heating mechanisms could induce drug-polymer interaction and change the properties of dissolution. Many benefits such as improving product quality, increasing energy efficiency and reducing times can be obtained by microwaves. This paper summarized characteristics of the microwave irradiation technique, new preparation techniques and formulation process in pharmaceutical industry by microwave irradiation technology. The microwave technology provides a new clue for heating and drying in the field of pharmaceutics.

  11. Synthesis and characterization of pyrite (FeS{sub 2}) using microwave irradiation

    SciTech Connect

    Kim, Eun Jung; Batchelor, Bill

    2009-07-01

    A procedure using microwave irradiation was studied to develop a fast and reliable method for synthesizing pyrite. Pyrite was successfully synthesized within a few minutes via reaction of ferric iron and hydrogen sulfide under the influence of irradiation by a conventional microwave oven. The SEM-EDX study revealed that the nucleation and growth of pyrite occurred on the surface of elemental sulfur, where polysulfides are available. Compared to conventional heating, using microwave energy results in rapid (<1 min) formation of smaller particulates of pyrite. Higher levels of microwave power can form pyrite even faster, but faster reaction can lead to the formation of pyrite with defects.

  12. Variable frequency microwave moisture leveling

    SciTech Connect

    Hamann, M.R.

    1999-07-01

    A variable frequency microwave system was examined to replace an existing carousel resistance heating line as the method for drying of mouth swabs for the pharmaceutical industry. A pharmaceutical manufacturer located in Northern Illinois had a resistive heating system that was not drying product satisfactorily, thus requiring additional ambient drying time even after a 30-minute drying cycle. Since the swabs are used for the healthcare industry, the amount of moisture present after drying was critical to avoid the formation of mold on the product that could have lead to dissatisfied customers. Variable frequency microwave moisture leveling allowed better product quality while turning the manufacturing operation into just in time delivery. During pilot scale testing, a 300 times cycle improvement was realized for variable frequency microwave compared to the conventional carousel resistive drying unit (24 hours to 5 minutes). The projected total cost of the variable frequency microwave system is $1 million, with 25% of the cost in the microwave unit and 70% of the cost in a new autobagging system. The author projected a $0.58 million saving per year in reduced operational costs with productivity increases. Although the project would have had a 1.8 year payback time, it was not implemented due to the capital expense and risk of an unknown technology.

  13. Using wet microalgae for direct biodiesel production via microwave irradiation.

    PubMed

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

    2013-03-01

    To address the large energy consumption of microalgae dewatering and to simplify the conventional two-step method (cellular lipid extraction and lipid transesterification) for biodiesel production, a novel process for the direct conversion of wet microalgae biomass into biodiesel by microwave irradiation is proposed. The influences of conventional thermal heating and microwave irradiation on biodiesel production from wet microalgae biomass were investigated. The effects of using the one-step (simultaneous lipid extraction and transesterification) and two-step methods were also studied. Approximately 77.5% of the wet microalgal cell walls were disrupted under microwave irradiation. The biodiesel production rate and yield from wet microalgae biomass obtained through the one-step process using microwave irradiation were 6-fold and 1.3-fold higher than those from wet microalgae obtained through the two-step process using conventional heating.

  14. Inactivation of Clostridium difficile spores by microwave irradiation.

    PubMed

    Ojha, Suvash Chandra; Chankhamhaengdecha, Surang; Singhakaew, Sombat; Ounjai, Puey; Janvilisri, Tavan

    2016-04-01

    Spores are a potent agent for Clostridium difficile transmission. Therefore, factors inhibiting spores have been of continued interest. In the present study, we investigated the influence of microwave irradiation in addition to conductive heating for C. difficile spore inactivation in aqueous suspension. The spores of 15 C. difficile isolates from different host origins were exposed to conductive heating and microwave irradiation. The complete inhibition of spore viability at 10(7) CFU/ml was encountered following microwave treatment at 800 W for 60 s, but was not observed in the conductive-heated spores at the same time-temperature exposure. The distinct patterns of ultrastructural alterations following microwave and conductive heat treatment were observed and the degree of damages by microwave was in the exposure time-dependent manner. Microwave would therefore be a simple and time-efficient tool to inactivate C. difficile spores, thus reducing the risk of C. difficile transmission.

  15. [Sorption characteristics of surfactant onto bentonite using microwave irradiation].

    PubMed

    Li, Ji-Wu; Zhu, Li-Zhong; Cai, Wei-Jian

    2007-11-01

    The sorption curve of cetylpyridinium chloride (CPC) onto bentonite by microwave irradiation was studied. The effects of microwave reaction time and CPC concentration on interlayer spacing and organic carbon content of organobentonite were tested, respectively. Thermodynamics and kinetics of sorption of CPC onto bentonite by microwave irradiation were studied. The saturated adsorption amount of CPC to bentonite with microwave irradiation time from 90 s to 120 s was equal to that of conventional sorption, up to 0.001 63 mol x g(-1). On the condition of microwave irradiation time with 2 min and concentration of CPC with 1.20 mmol x L(-1), the interlayer spacing was attained to 2.44 nm at the best, and organic carbon content was 23.45%. The atomic force microscopy (AFM) showed that the typical layer morphological structure of bentonite was not devastated by microwave. Contrast to conventional sorption, sorption of CPC onto bentonite was greatly influenced by microwave, velocity constant of sorption reaction was increased 107.6 times, and free energy of sorption reaction system was decreased.

  16. Improving enzyme immobilization in mesocellular siliceous foams by microwave irradiation.

    PubMed

    Wang, Anming; Liu, Mingqing; Wang, Hua; Zhou, Cheng; Du, Zhiqiang; Zhu, Shemin; Shen, Shubao; Ouyang, Pingkai

    2008-09-01

    Microwave irradiation was used to immobilize papain and penicillin acylase in mesocellular siliceous foams (MCFs) at low temperature. The maximum loading of papain reached 984.1 mg/g, 1.26 times that obtained using the conventional, non-microwave-assisted method. The half-life (t(0.5)) of papain immobilized in MCFs by microwave irradiation at 80 degrees C was 17 h, 5.21 times that of papain immobilized by conventional means. The activities of papain and penicillin acylase immobilized with the microwave-assisted method were 779.6 U/mg and 141.8 U/mg respectively, 1.86 and 1.39 times of those obtained without microwave immobilization. Using microwave irradiation it only took 140 s for penicillin acylase, an enzyme of large dimensions, to be immobilized in MCFs. In contrast, it took 15 h to do the same using the conventional method. The results showed that microwave irradiation improved the adsorption and immobilization of enzymes in mesocellular siliceous foams.

  17. Degradation of phenol under combined irradiation of microwaves and ultrasound.

    PubMed

    Wu, Zhi-Lin; Ondruschka, Bernd; Cravotto, Giancarlo

    2008-11-01

    A novel combined system of irradiation by microwaves and ultrasound is used to efficiently destroy phenol in aqueous solutions via sono-generated hydroxyl radicals and H2O2, in conjunction with the rapid thermal effect of microwaves on polar chemicals. Microwave irradiation enhances the sono-degradation of phenol without any additional catalyst although the effect is more marked when H2O2 is added. The degradation of phenol by MW or US alone or by combined irradiation of MW-US follows zero order kinetics. Degradation rate constants and yields of the main intermediates, catechol and hydroquinone, follow the order of MW-US > MW > US. The degradation rate also increases with higher reaction temperature in the MW reactor. The synergistic effects of MW and US were observed at 93 degrees C without addition of H2O2 and at 60 degrees C with addition of H2O2.

  18. 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.

  19. 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

  20. '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...

  1. 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...

  2. '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...

  3. Hydrolytic fragmentation of seed gums under microwave irradiation.

    PubMed

    Singh, V; Tiwari, A

    2009-03-01

    The seed gum solutions of Ipomoea purga, Ipomoea palmata, Ipomoea dasysperma, Cyanaposis tetragonolobus (Guar gum) and Crotolaria medicaginea were microwave (MW) irradiated and their degradation to oligo and monosaccharides was investigated. The gum solutions were fragmented into oligosaccharides/constituent monosaccharides depending upon the length of MW exposure in presence of catalytic amount of mineral acid or even when no acid was used. A mechanism for the microwave induced hydrolytic degradation of the seed gums has been proposed. The MW exposure time required for the partial and complete degradation of the gums was found dependent on the types of the linkages and degree of the branching present in the gums.

  4. Control of airborne and liquid-borne fungal and pet allergens using microwave irradiation.

    PubMed

    Wu, Yan; Yao, Maosheng

    2013-01-01

    In this study, the dog, cat allergens (Can f 1 and Fel d 1) and fungal allergens (Alt a 1 and Asp f 1) were aerosolized and exposed to the microwave irradiation (2450 MHz) at different output powers for up to 2 min. The allergen bioaerosols were collected by a BioSampler, and analyzed using enzyme-linked immunosorbent assay (ELISA). Control and microwave-irradiated Asp f 1 allergens were also tested with IgEs in human blood sera samples. For airborne Asp f 1 and Alt a 1 allergens, the allergenicity was shown to decrease about 50% when exposed to microwave irradiation at 385 and 119 W and relatively no change at 700 W. For airborne Can f 1 allergen, the allergenicity was shown to increase about 70% when exposed to the irradiation at 385 W, but remained relatively unchanged at 700 and 119 W. In contrast, airborne Fel d 1 allergen was observed to lose allergenicity completely at 700 W, and retained about 40% and 80% at 385 and 119 W, respectively. Radioallergosorbent (RAST) tests showed that changes detected in IgE levels in human blood sera mixtures were not statistically significant for the control and microwave-irradiated waterborne Asp f 1 allergens. This study implies that although certain allergenicity reductions were observed for some allergens in certain cases, particular care should be taken when the microwave irradiation is used to disinfect food, water, and air because of its complex effects.

  5. 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.

  6. Response of Aspergillus nidulans and Physarum polycephalum to microwave irradiation.

    PubMed

    Mezykowski, T; Bal, J; Debiec, H; Kwarecki, K

    1980-06-01

    The influence of microwaves on genetic processes in Aspergillus nidulans and Physarum polycephalum was investigated. Suspensions of organisms were exposed in the far zone to 2450-MHz waves at 10 mW/cm2 for one hour in both CW and pulsed (1 microsecond, 600 pps) fields. Spores of A. nidulans were irradiated before and during germination. No changes in survival rate or in frequency of morphological mutation were found. Polycephalum under the influence of CW microwaves incorporated 3H-Thymine into DNA at a rate five times that of controls and twice that of thermal controls. The accelerated synthesis may reflect more efficient volume heating by microwaves, or in the presence of microthermal gradients in suspensions, or field-specific influences in concern with focal or volume heating.

  7. Fast transmethylation of serum lipids using microwave irradiation.

    PubMed

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

    2012-11-01

    Microwave irradiation as the energy source for one-step direct transesterification of fatty acids in human serum lipids was examined in a solvent system of methanol: hexane: acetyl chloride based on a Lepage & Roy assay. Innovative and explosion proof single-mode or multimode microwave accelerated reaction system was employed. Recoveries were calculated as the percentage of fatty acid concentrations measured by microwave assay to those by the reference method of the Lepage & Roy assay that utilized conductive heating at 100 °C for 60 min. Under 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 the 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.

  8. Nonthermal effect of microwave irradiation in nonaqueous enzymatic esterification.

    PubMed

    Wan, Hui-da; Sun, Shi-yu; Hu, Xue-yi; Xia, Yong-mei

    2012-03-01

    Microwave has nonthermal effects on enzymatic reactions, mainly caused by the polarities of the solvents and substrates. In this experiment, a model reaction with caprylic acid and butanol that was catalyzed by lipase from Mucor miehei in alkanes or arenes was employed to investigate the nonthermal effect in nonaqueous enzymatic esterification. With the comparison of the esterification carried by conventional heating and consecutive microwave irradiation, the positive nonthermal effect on the initial reaction rates was found substrate concentration-dependent and could be vanished ostensibly when the substrate concentration was over 2.0 mol L(-1). The polar parameter log P well correlates the solvent polarity with the microwave effect, comparing to dielectric constant and assayed solvatochromic solvent polarity parameters. The log P rule presented in conventional heating-enzymatic esterification still fits in the microwaved enzymatic esterification. Alkanes or arenes with higher log P provided positive nonthermal effect in the range of 2 ≤ log P ≤ 4, but yielded a dramatic decrement after log P = 4. Isomers of same log P with higher dielectric constant received stronger positive nonthermal effect. With lower substrate concentration, the total log P of the reaction mixture has no obvious functional relation with the microwave effect.

  9. 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...

  10. 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.

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

    PubMed

    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. (1)H 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.

  12. Recent applications of microwave irradiation to medicinal chemistry.

    PubMed

    Alcázar, Jesús; Oehlrich, Daniel

    2010-02-01

    The demands made on the pharmaceutical industry are changing at an unprecedented pace, making modern drug discovery dependent on high speed organic synthesis. Over the last few years, different technologies have been introduced in medicinal chemistry laboratories in order to improve their productivity. Microwave-assisted organic synthesis is proving to be instrumental in the rapid synthesis of compounds with new and improved biological activities. This review highlights the application of this approach as a way to explore analogue synthesis in medicinal chemistry over the last 3 years. We describe a number of examples taken from the literature that are related to various targets within different therapeutic areas. Clearly microwave irradiation is becoming a fundamental tool for optimizing key steps in the synthesis of target compounds within the field of drug discovery.

  13. 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.

  14. Changes in Thermoregulatory Behavior during Microwave Irradiation,

    DTIC Science & Technology

    level. For ectothermic species, these behaviors represent most of the thermoregulatory response available to the organism . For endothermic species, these...Voluntary behavioral action is an organism’s first defense against exogenous thermal challenge. Endotherms and ectotherms alike use behavioral...diverse as the thermotropisms of unicellular organisms and the complex behavior-plus-technology of man’s lunar walk share a common purpose--that of

  15. [Development of the Chlamydomonas actinochloris culture after microwave irradiation].

    PubMed

    Grigor'eva, O O; Berezovskaia, M A; Datsenko, A I

    2012-01-01

    Effect of the microwave irradiation on the subsequent development of the Chlamydomonas actinochloris culture is studied. The number of cells in the suspension was controlled and photoluminescence measurements were performed for 25 days to estimate the functional state of the cells. The exposure at a dose of 80 J/g is shown to negligibly affect the green alga, whereas the 122 J/g dose led to deterioration of the functional state and, thereafter, to the death of most cells. However, the survivors intensively developed, the culture restored the normal state for 20 days, reached and later even left behind the control sample in development.

  16. 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.

  17. 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.

  18. 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.

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

    PubMed Central

    2008-01-01

    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.

  20. 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.

  1. Synergistic effect of microwave irradiation and CaF2 on vanadium leaching

    NASA Astrophysics Data System (ADS)

    Wang, Jing-peng; Zhang, Yi-min; Huang, Jing; Liu, Tao

    2017-02-01

    The effect and mechanism of microwave irradiation on vanadium leaching were studied via a comparison between microwave heating and conventional heating. The results show a synergistic effect of microwave irradiation and calcium fluoride (CaF2) on the vanadium leaching efficiency. It is confirmed that the vanadium leaching process can be improved by microwave irradiation when CaF2 is present. The leaching rate of vanadium under microwave irradiation is increased by 8%-15% when 5wt% CaF2 is added; by contrast, in the absence of CaF2, the leaching rate is almost unaffected compared to that by conventional heating. Morphological analysis reveals that the particles are gradually eroded by acid under microwave irradiation, whereas some of the fine particles in samples subjected to conventional heating are tightly covered by a flocculent silicate product. Moreover, a large amount of Al and V and a small amount of Si are dissolved from samples under microwave heating, as revealed by the elemental analysis of leachates. Fourier transform infrared spectroscopic analysis also indicates a higher mass transfer coefficient in the diffusion layer of the raw material by microwave irradiation. When CaF2 is present, the reaction energy barrier is lowered and the leaching process is controlled by the tightly covered product layer, resulting in a prominent effect of microwave irradiation.

  2. Preparation and evaluation of swelling induced-orally disintegrating tablets by microwave irradiation.

    PubMed

    Sano, Syusuke; Iwao, Yasunori; Kimura, Susumu; Itai, Shigeru

    2011-09-15

    A major challenge in the development of orally disintegrating tablets (ODTs) is to achieve a good balance between tablet hardness and disintegration time. In this study, an advanced method was demonstrated to improve these opposing properties in a molded tablet using a one-step procedure that exploits the swelling induced by microwave treatment. Wet molded tablets consisting of the delta form of mannitol and silicon dioxide were prepared and microwave-heated to generate water vapor inside the tablets. This induced either swelling or shrinking of tablets, in the extent of each being dependent on tablet formulation and manufacturing conditions. A two-level full factorial design method was used to evaluate the effects of several variables in formulation and manufacturing conditions on the tablet properties, hardness, disintegration time and change in shape. The variables investigated in this study were: ratio of silicon dioxide in formulation, water volume added in granulation, ratio of water absorbed by silicon dioxide prior to granulation, and microwave irradiation time. Swelling of tablet by microwave irradiation was observed in the batches with high ratio of silicon dioxide and low levels of water volume. The disintegration time was clearly shortened by induction of the swelling, while tablet hardness increased. We demonstrated that the water vapor generated by microwave irradiation promoted a change in the crystalline form of mannitol from delta to beta, and that this may have contributed to an increase in tablet hardness. Additionally, it was found that new solid bridges were formed between the granules in the tablet via the pathway from dissolution of mannitol in water vapor to congelation, resulting in an increase in tablet hardness. Thus, both tablet hardness and disintegration properties of the molded tablets were improved by the proposed one-step method and the appropriate ranges for variables are indicated. In addition, multiple regression modeling was

  3. Quantum phase-slip junction under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Di Marco, A.; Hekking, F. W. J.; Rastelli, G.

    2015-05-01

    We consider the dynamics of a quantum phase-slip junction (QPSJ), a dual Josephson junction, connected to a microwave source with frequency ωmw. With respect to an ordinary Josephson junction, a QPSJ can sustain dual Shapiro steps, consisting of well-defined current plateaus at multiple integers of e ωmw/π in the current-voltage (I -V ) characteristic. The experimental observation of these plateaus has been elusive up to now. We argue that thermal as well as quantum fluctuations can smear the I -V characteristic considerably. In order to understand these effects, we study a current-biased QPSJ under microwave irradiation and connected to an inductive and resistive environment. We find that the effect of the fluctuations is governed by the resistance of the environment and by the ratio of the phase-slip energy and the inductive energy. Our results are of interest for experiments aiming at the observation of dual Shapiro steps in QPSJ devices for the definition of a new quantum current standard.

  4. Malachite green adsorption onto natural zeolite and reuse by microwave irradiation.

    PubMed

    Han, Runping; Wang, Yu; Sun, Qing; Wang, Lulu; Song, Jiyun; He, Xiaotian; Dou, Chanchan

    2010-03-15

    Natural zeolite was used for the removal of malachite green (MG) from aqueous solution in batch mode and reused by microwave irradiation. The isotherm data were analyzed by the Langmuir, Freundlich, Redlich-Peterson, and Koble-Corrigan isotherm model. The better fit for the equilibrium process was Koble-Corrigan model. The kinetic studies indicated that the adsorption followed the pseudo-second-order kinetic. Thermodynamic calculations showed that the adsorption was spontaneous and endothermic process. Spent zeolite was treated by microwave irradiation and it was found that yield of regeneration was 85.8% in the case of microwave irradiated time 10 min at 160 W.

  5. 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.

  6. Microwaves and cellular immunity. I. Effect of whole body microwave irradiation on tumor necrosis factor production in mouse cells.

    PubMed

    Fesenko, E E; Makar, V R; Novoselova, E G; Sadovnikov, V B

    1999-10-01

    Whole body microwave sinusoidal irradiation of male NMRI mice with 8.15-18 GHz (1 Hz within) at a power density of 1 microW/cm2 caused a significant enhancement of TNF production in peritoneal macrophages and splenic T lymphocytes. Microwave radiation affected T cells, facilitating their capacity to proliferate in response to mitogenic stimulation. The exposure duration necessary for the stimulation of cellular immunity ranged from 5 h to 3 days. Chronic irradiation of mice for 7 days produced the decreasing of TNF production in peritoneal macrophages. The exposure of mice for 24 h increased the TNF production and immune proliferative response, and these stimulatory effects persisted over 3 days after the termination of exposure. Microwave treatment increased the endogenously produced TNF more effectively than did lipopolysaccharide, one of the most potential stimuli of synthesis of this cytokine. The role of microwaves as a factor interfering with the process of cell immunity is discussed.

  7. 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.

  8. 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...

  9. Brønsted acid-catalyzed Nazarov cyclization of pyrrole derivatives accelerated by microwave irradiation.

    PubMed

    Bachu, Prabhakar; Akiyama, Takahiko

    2009-07-15

    The Brønsted acid-catalyzed Nazarov cyclization of pyrrole derivatives was developed. Microwave irradiation accelerated the Nazarov cyclization significantly at 40 degrees C to give cyclopenta[b]pyrrole derivatives in excellent yields with high trans selectivity.

  10. Selective oxidation of glycosyl sulfides to sulfoxides using magnesium monoperoxyphthalate and microwave irradiation.

    PubMed

    Chen, Ming-Yi; Patkar, Laxmikant Narhari; Lin, Chun-Cheng

    2004-04-16

    A protocol that uses moist magnesium monoperoxyphthalate (MMPP) as an oxidant under microwave irradiation rapidly yields a variety of glycosyl sulfoxides from corresponding sulfides in high yields with high selectivity.

  11. 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...

  12. The separated electric and magnetic field responses of luminescent bacteria exposed to pulsed microwave irradiation

    NASA Astrophysics Data System (ADS)

    Williams, Catrin F.; Geroni, Gilles M.; Pirog, Antoine; Lloyd, David; Lees, Jonathan; Porch, Adrian

    2016-08-01

    Electromagnetic fields (EMFs) are ubiquitous in the digital world we inhabit, with microwave and millimetre wave sources of non-ionizing radiation employed extensively in electronics and communications, e.g., in mobile phones and Wi-Fi. Indeed, the advent of 5G systems and the "internet of things" is likely to lead to massive densification of wireless networks. Whilst the thermal effects of EMFs on biological systems are well characterised, their putative non-thermal effects remain a controversial subject. Here, we use the bioluminescent marine bacterium, Vibrio fischeri, to monitor the effects of pulsed microwave electromagnetic fields, of nominal frequency 2.5 GHz, on light emission. Separated electric and magnetic field effects were investigated using a resonant microwave cavity, within which the maxima of each field are separated. For pulsed electric field exposure, the bacteria gave reproducible responses and recovery in light emission. At the lowest pulsed duty cycle (1.25%) and after short durations (100 ms) of exposure to the electric field at power levels of 4.5 W rms, we observed an initial stimulation of bioluminescence, whereas successive microwave pulses became inhibitory. Much of this behaviour is due to thermal effects, as the bacterial light output is very sensitive to the local temperature. Conversely, magnetic field exposure gave no measurable short-term responses even at the highest power levels of 32 W rms. Thus, we were able to detect, de-convolute, and evaluate independently the effects of separated electric and magnetic fields on exposure of a luminescent biological system to microwave irradiation.

  13. 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 ...

  14. 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...

  15. Steady States of the Inhomogenous Microwave Irradiated Quantum Hall Gas

    NASA Astrophysics Data System (ADS)

    Auerbach, Assa; Finkler, Ilya; Halperin, Bertrand; Yacoby, Amir

    2005-03-01

    To explain the observation of Zero-Resistance states (ZRS) in Microwave irradiated Quantum Hall gases[1], it has been proposed[2] that under appropriate conditions the sample will break into domains of photogenerated fields. In the absence of disorder induced pinning, motion of domain walls results in a ZRS state. In order to treat the effects of long wavelength disorder, we construct a Lyapunov functional for systems with uniform Hall conductivity. We use it to derive stability conditions on the domain structure and to compute the conductance. We show that weak white noise disorder does not destroy the ZRS although it produces current fluctuations. In contrast, separable and correlated disorder pin the domain walls, and produce a finite conductance and a photovoltage as demonstrated by one dimensional, and simple two dimensional, potentials.1. R.G. Mani et.al. Nature, 420, 646 (2002); M.A. Zudov et.al., Phys. Rev. Lett. 90, 046807 (2003).2. A.V. Andreev, I.L. Aleiner, and A.J. Millis, PRL 91, 056803 (2003).

  16. Advances on simultaneous desulfurization and denitrification using activated carbon irradiated by microwaves.

    PubMed

    Ma, Shuang-Chen; Gao, Li; Ma, Jing-Xiang; Jin, Xin; Yao, Juan-Juan; Zhao, Yi

    2012-06-01

    This paper describes the research background and chemistry of desulfurization and denitrification technology using microwave irradiation. Microwave-induced catalysis combined with activated carbon adsorption and reduction can reduce nitric oxide to nitrogen and sulfur dioxide to sulfur from flue gas effectively. This paper also highlights the main drawbacks of this technology and discusses future development trends. It is reported that the removal of sulfur dioxide and nitric oxide using microwave irradiation has broad prospects for development in the field of air pollution control.

  17. 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.

  18. 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.

  19. Control of the microwave characteristics of composite materials filled with carbon nanotubes using UV irradiation

    NASA Astrophysics Data System (ADS)

    Usanov, D. A.; Skripal', A. V.; Romanov, A. V.

    2013-03-01

    The complex permittivities of composite materials that are based on the two-component epoxy binder with various volume concentrations of the UV-irradiated multilayer carbon nanotubes are determined using the microwave transmission spectra. The effect of the UV-irradiation time on the mean conductivity of the nanotubes in the composite in the microwave range is studied. It is demonstrated that the limitations on the working volume of the chamber in which the UV irradiation of the carbon nanotubes is performed substantially affects the electrophysical characteristics of the nanotubes.

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

    PubMed

    Garber, Eric A E; Thole, Joseph

    2015-06-11

    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%.

  1. Effects of Normothermic Conditioned Microwave Irradiation on Cultured Cells Using an Irradiation System with Semiconductor Oscillator and Thermo-regulatory Applicator

    PubMed Central

    Asano, Mamiko; Sakaguchi, Minoru; Tanaka, Satoshi; Kashimura, Keiichiro; Mitani, Tomohiko; Kawase, Masaya; Matsumura, Hitoshi; Yamaguchi, Takako; Fujita, Yoshikazu; Tabuse, Katsuyoshi

    2017-01-01

    We investigated the effects of microwave irradiation under normothermic conditions on cultured cells. For this study, we developed an irradiation system constituted with semiconductor microwave oscillator (2.45 GHz) and thermos-regulatory applicator, which could irradiate microwaves at varied output powers to maintain the temperature of cultured cells at 37 °C. Seven out of eight types of cultured cells were killed by microwave irradiation, where four were not affected by thermal treatment at 42.5 °C. Since the dielectric properties such as ε’, ε” and tanδ showed similar values at 2.45 GHz among cell types and media, the degree of microwave energy absorbed by cells might be almost the same among cell types. Thus, the vulnerability of cells to microwave irradiation might be different among cell types. In HL-60 cells, which were the most sensitive to microwave irradiation, the viability decreased as irradiation time and irradiation output increased; accordingly, the decrease in viability was correlated to an increase in total joule. However, when a high or low amount of joules per minute was supplied, the correlation between cellular viability and total joules became relatively weak. It is hypothesized that kinds of cancer cells are efficiently killed by respective specific output of microwave under normothermic cellular conditions. PMID:28145466

  2. Improvement of coal water slurry property through coal physicochemical modifications by microwave irradiation and thermal heat

    SciTech Connect

    Jun Cheng; Junhu Zhou; Yanchang Li; Jianzhong Liu; Kefa Cen

    2008-07-15

    To improve the coal water slurry (CWS) property made from Chinese Shenhua coal with high inherent moisture and oxygen contents, microwave irradiation and thermal heat were employed to modify the coal physicochemical property. Microwave irradiation reduces the inherent moisture and reforms the oxygenic function groups, while it decreases the total specific surface area. Thermal heat markedly decreases the inherent moisture, volatile, and oxygen contents, while it dramatically increases the total specific surface area. Therefore, microwave irradiation gives a higher CWS concentration and a better rheological behavior than thermal heat, while it remarkably reduces the operation time and energy consumption. The maximum CWS concentration given by microwave irradiation at 420 W for 60 s is 62.14%, which is not only higher than that of 60.41% given by thermal heat at 450{sup o}C for 0.5 h but also higher than the initial 58.23%. Meanwhile, the minimum shear stress given by microwave irradiation is 36.4 Pa at the shear rate of 100 s{sup -1}, which is not only lower than that of 42.4 Pa given by thermal heat but also lower than the initial 79.8 Pa. The minimum unit energy consumption of 0.115 kWh/(kg of coal) and electricity cost of 4.6 U.S. $/(ton of coal) for CWS concentration promotion by 1% are obtained at 420 W for 20 s in the microwave oven. The unit energy consumptions for CWS concentration promotion and inherent moisture removal by thermal heat are, respectively, 214 and 22.5 times higher than those by microwave irradiation, while the energy use efficiencies are on the converse. 27 refs., 11 figs., 2 tabs.

  3. Dechlorination of organochloride waste mixture by microwave irradiation before forming solid recovered fuel.

    PubMed

    Liu, Zhen; Wang, Han-Qing; Zhang, Xiao-Dong; Liu, Jian-Wen; Zhou, Yue-Yun

    2016-11-22

    In order to form a modified solid recovered fuel (SRF) with low chlorine content, high calorific value and well combustion performance, low temperature microwave irradiation was applied to remove the chlorine of the organochloride waste mixture before they were mixed to form SRF. The optimizing conditions of final temperature, microwave absorbents and heating rate were also detected to obtain high dechlorination ratio and high ratio of hydrogen chloride (HCl) to volatiles. In the temperature range of 220-300°C, 280°C would be chose as the optimal low microwave modified temperature concerning at which the dechlorination ratio was high and ratio of HCl to volatiles was relatively high as well; The use of microwave absorbents of graphite and silicon carbide (SiC) had a pronounced effect on the dechlorination of organochloride waste mixture, and the dechlorination ratio was increased significantly which could be reached to 87%, almost 20% higher than absorbent absent sample; The heating rate should set be not too fast nor too slow, and there was no big difference between the heating rate of 13°C/min and 15°C/min; The content of Cl of modified SRF is dramatically decreased and reaches to a low level 0.328%. Hence, the modified SRF can be ascended from the third class to the second class according to the Finland chlorine Classes I-III. Moreover, the combustibility of modified SRF was substantial improved compared to the traditional SRF. The low heating value was almost 20.56MJ/kg which is close to the LHV of lignite coal and bituminous coal in China, and it increased by 60% over that of traditional SRF. Removing chlorine of organochloride waste mixture before they are mixed with other kinds of combustible waste to form a modified SRF which is expected to be an alternative fuel for combustion in the future.

  4. The microwave heating mechanism of N-(4-methoxybenzyliden)-4-butylaniline in liquid crystalline and isotropic phases as determined using in situ microwave irradiation NMR spectroscopy.

    PubMed

    Tasei, Yugo; Tanigawa, Fumikazu; Kawamura, Izuru; Fujito, Teruaki; Sato, Motoyasu; Naito, Akira

    2015-04-14

    Microwave heating effects are widely used in the acceleration of organic, polymerization and enzymatic reactions. These effects are primarily caused by the local heating induced by microwave irradiation. However, the detailed molecular mechanisms associated with microwave heating effects on the chemical reactions are not yet well understood. This study investigated the microwave heating effect of N-(4-methoxybenzylidene)-4-butylaniline (MBBA) in liquid crystalline and isotropic phases using in situ microwave irradiation nuclear magnetic resonance (NMR) spectroscopy, by obtaining (1)H NMR spectra of MBBA under microwave irradiation. When heated simply using the temperature control unit of the NMR instrument, the liquid crystalline MBBA was converted to the isotropic phase exactly at its phase transition temperature (Tc) of 41 °C. The application of microwave irradiation at 130 W for 90 s while maintaining the instrument temperature at 20 °C generated a small amount of isotropic phase within the bulk liquid crystal. The sample temperature of the liquid crystalline state obtained during microwave irradiation was estimated to be 35 °C by assessing the linewidths of the (1)H NMR spectrum. This partial transition to the isotropic phase can be attributed to a non-equilibrium local heating state induced by the microwave irradiation. The application of microwave at 195 W for 5 min to isotropic MBBA while maintaining an instrument temperature of 50 °C raised the sample temperature to 160 °C. In this study, the MBBA temperature during microwave irradiation was estimated by measuring the temperature dependent chemical shifts of individual protons in the sample, and the different protons were found to indicate significantly different temperatures in the molecule. These results suggest that microwave heating polarizes bonds in polar functional groups, and this effect may partly explain the attendant acceleration of organic reactions.

  5. 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...

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

    NASA Astrophysics Data System (ADS)

    Asakuma, Yusuke; Munenaga, Takuya; Nakata, Ryosuke

    2016-09-01

    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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2007-04-01

    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.

  9. 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.

  10. 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)

  11. [Research on degradation of methylene blue by coal bottom ash-microwave irradiation method].

    PubMed

    Wu, Shi-Wei; Li, Na; Li, Guang-Zhe; Li, Guo-De

    2010-05-01

    Coal bottom ash is rich in metals and transition metals, and with microwave irradiation these metals can effectively degradate organic matter. Methylene blue degradation by coal bottom ash-microwave irradiation mainly through hydroxyl radicals to degrade organic matter, and metals and rare metals in bottom ash can be used as a catalyst for deep oxidation of organic matter, can reduce processing costs, and reduce environmental pollution. In the present paper the main parameters including the amount of coal bottom ash, H2O2 dosage and time of microwave irradiation were investigated. The UV-visible spectra of methylene blue were determined. The results show that: under coal bottom ash and H2O2 microwave condition the degeneration rate of methylene blue was almost 100%. The dosage of coal ash can accelerate the reaction process, speeding up the degradation of methylene blue. The increase of H2O2 may provide more * OH and speed up the reaction process, but when up to a certain amount, the influence is weakened. The lengthening of microwave time may enhance the reaction temperature, and urge the methylene blue to degrade completely. For 0.125 g x L(-1) of methylene blue, by adding 1.0 g coal bottom ash, 5 mL H2O2 and under mesotherm microwave temperature for 4 min, the methylene blue can be all degradated.

  12. Influence of microwave irradiation on boron concentrate activation with an emphasis on surface properties

    NASA Astrophysics Data System (ADS)

    Jiang, Tao; Zhang, Qiaoyi; Liu, Yajing; Xue, Xiangxin; Duan, Peining

    2016-11-01

    In this study, we employed microwave irradiation for activating boron concentrate, an abundant but low-grade boron mineral resource in China. The boron concentrate was pretreated by microwave irradiation based on TG-DTG-DSC analysis, and the influence of each parameter on processing efficiency was characterized using chemical analysis, XRD, SEM, FTIR and particle distribution analysis. Subsequently, the surface properties of boron concentrate and the mechanism of microwave irradiation was analyzed. Our results indicate that microwave irradiation decreased the processing temperature and shortened the roasting time by accelerating dehydroxylation and oxidation reactions in the boron concentrate, reducing the particle diameter and damaging the microstructure of the minerals, and it increased the B2O3 activity of boron from 64.68% to 86.73%, greater than the optimal conventional treatment. Compared with the simple thermal field, microwave roasting obviously increased ability of the boron concentrate to absorb OH- in the leachant and promoted boron leaching by expanding the contact area of the mineral exposed to leachant, boosting the amount of Mg2+ and Fe3+ on mineral surfaces, and increasing the hydrophilicity of the boron concentrate respectively. It enhanced the γSVLW and γSV- of boron concentrate from 29.15 mJ/m2 and 5.07 mJ/m2 to 37.07 mJ/m2 and 12.41 mJ/m2.

  13. Effect of ionic liquid properties on lipase stabilization under microwave irradiation

    SciTech Connect

    Zhao, Hua; Baker, Gary A; Song, Zhiyan; Olubajo, Olarongbe; Zanders, Lavezza; Campbell, Sophia

    2009-01-01

    Ionic liquids (ILs) as neoteric solvents and microwave irradiation as alternative energy source are becoming two important tools for many enzymatic reactions. However, it is not well understood what properties of ILs govern the enzyme stabilization, and whether the microwave irradiation could activate enzymes in ILs. To tackle these two important issues, the synthetic activities of immobilized Candida antarctica lipase B (Novozyme 435) were examined in more than twenty ILs through microwave heating. Under microwave irradiation, enhanced enzyme activities were observed when the enzyme was surrounded by a layer of water molecules. However, such enhancement diminished when the reaction system was dried. To understand the effect of IL properties, the enzyme activities under microwave irradiation were correlated with the viscosity, polarity and hydrophobicity (log P) of ILs, respectively. The initial reaction rates bear no direct relationship with the viscosity and polarity (in terms of dielectric constant and EN T ) of ILs, but have a loose correlation (a bell curve) with log P values. The enzyme stabilization by ILs was explained from aspects of hydrogen-bond basicity of anions, dissolution of the enzyme, ionic association strength of anions, and substrate ground-state stabilization by ILs.

  14. Rapid solid-phase peptide synthesis using thermal and controlled microwave irradiation.

    PubMed

    Bacsa, Bernadett; Desai, Bimbisar; Dibó, Gábor; Kappe, C Oliver

    2006-10-01

    A rapid and efficient microwave-assisted solid-phase synthesis method is described for the preparation of the nonapeptide WDTVRISFK, using conventional Fmoc/Bu(t) orthogonal protection strategy. The synthesis protocol is based on the use of cycles of pulsed microwave irradiation with intermittent cooling of the reaction during the removal of the Fmoc protecting group and during the coupling. The desired nonapeptide was obtained in highest yield and purity by employing MicroKan technology. The chemical reactions were carried out in a single-mode microwave reactor, equipped with a fiber-optic probe to monitor the reaction temperature continuously.

  15. Syntheses of new tuberculosis inhibitors promoted by microwave irradiation

    PubMed Central

    De Rosa, Maria; Gising, Johan; Odell, Luke R.

    2014-01-01

    Tuberculosis (TB) represents a major public health problem. The growing number of (extensively) multi-drug resistance cases indicates that there is an urgent need for discovery of new anti-TB entities, addressed towards new and specific targets, and continuous development of fast and efficient synthetic strategies to access them easily. Microwave-assisted chemistry is well suited for small-scale laboratory synthetic work, allowing full control of reaction conditions, such as temperature, pressure, and time. Microwave-assisted high-speed organic synthesis is especially useful in the lead optimization phase of drug discovery. To illustrate the advantages of modern microwave heating technology, we herein describe applications and approaches that have been useful for the synthesis of new drug-like anti-TB compounds. PMID:24666224

  16. Syntheses of new tuberculosis inhibitors promoted by microwave irradiation.

    PubMed

    De Rosa, Maria; Gising, Johan; Odell, Luke R; Larhed, Mats

    2014-05-01

    Tuberculosis (TB) represents a major public health problem. The growing number of (extensively) multi-drug resistance cases indicates that there is an urgent need for discovery of new anti-TB entities, addressed towards new and specific targets, and continuous development of fast and efficient synthetic strategies to access them easily. Microwave-assisted chemistry is well suited for small-scale laboratory synthetic work, allowing full control of reaction conditions, such as temperature, pressure, and time. Microwave-assisted high-speed organic synthesis is especially useful in the lead optimization phase of drug discovery. To illustrate the advantages of modern microwave heating technology, we herein describe applications and approaches that have been useful for the synthesis of new drug-like anti-TB compounds.

  17. 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...

  18. 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...

  19. PREPARATION OF NOVEL METALLIC AND BIMETALLIC CROSS-LINKED POLY (VINYL ALCOHOL) NANOCOMPOSITES UNDER MICROWAVE IRRADIATION

    EPA Science Inventory

    A facile method utilizing microwave irradiation is described that accomplishes the cross-linking reaction of PVA with metallic and bimetallic systems. Nanocomposites of PVA-cross-linked metallic systems such as Pt, Cu, and In and bimetallic systems such as Pt-In, Ag-Pt, Pt-Fe, Cu...

  20. 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...

  1. 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...

  2. "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...

  3. Microwave irradiation induced band gap tuning of MoS2-TiO2 nanocomposites

    NASA Astrophysics Data System (ADS)

    Shakya, Jyoti; Mohanty, T.

    2016-05-01

    The MoS2-TiO2 nanocomposites have been synthesized by sol-gel method and characterized by different microscopic and spectroscopic techniques. The crystallinity of these nanocomposites has been confirmed by X-ray diffraction (XRD) analysis. The Raman spectrum of MoS2-TiO2 nanocomposites consists of three distinct peaks (E1 g, E1 2g and A1g) which are associated with TiO2 and MoS2. The morphological study is carried out by scanning electron microscope. The effect of microwave irradiation on the band gap of MoS2-TiO2 nanocomposites has been investigated; it is observed that the microwave irradiation causes decrease in the band gap of MoS2-TiO2 nanocomposites. The microwave treated MoS2-TiO2 thin films offers a novel process route in treating thin films for commercial applications.

  4. 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.

  5. Effect of Different Energy Levels of Microwave on Disinfection of Dental Stone Casts

    PubMed Central

    Robati Anaraki, Mahmood; Lotfipour, Farzaneh; Moslehifard, Elnaz; Momtaheni, Ali; Sigari, Pooyan

    2013-01-01

    Background and aims Current chemical methods may not efficiently disinfect dental stone casts. The aim of this study was to investigate if microwave irradiation is effective for disinfection of stone casts. Materials and methods In this laboratory study, three groups (n = 162) of prepared spherical stone beads as carriers with a diameter of 10 mm were inoculated by separately soaking in three broth culture media, each containing a study microorganism—Pseudomonas aeruginosa, Staphylococcus aureus or Candida albicans. Six inoculated carriers were used for every test, including irradiation in a household microwave oven at 300, 450, 600 or 900 W energy level, or soaking in 0.03%, 0.06%, 0.12%, 0.25% or 0.50% concentration of sodium hypochlorite solution, at 1, 2, or 3-minute test times. Positive and negative control groups were considered for each test. All treated carriers were then individually transferred to nutrient broth culture medium and one milliliter from each tube was cultured in nutrient agar media over night. Colony forming unit per milliliter (CFU/mL) was counted, and multi-factor ANOVA was used to analyze data (α = 0.05). Results Microwave irradiation at 600 W resulted in high-level disinfection in 3 minutes. Immersion of the stone casts in hypochlorite solution at 0.06% concentration resulted in disinfection after 2 minutes. Conclusion According to the results, high level disinfection of the stone casts can be achieved by microwave irradiation at 600 W in 3 minutes, similar to a validated chemical method. PMID:24082984

  6. ‘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...

  7. 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...

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Preliminary microwave irradiation of water solutions changes their channel-modifying activity.

    PubMed

    Fesenko, E E; Geletyuk, V I; Kazachenko, V N; Chemeris, N K

    1995-06-05

    Earlier we have shown that millimetre microwaves (42.25 GHz) of non-thermal power, upon direct admittance into an experiment bath, greatly influence activation characteristics of single Ca(2+)-dependent K+ channels (in particular, the channel open state probability, Po). Here we present new data showing that similar changes in Po arise due to the substitution of a control bath solution for a preliminary microwave irradiated one of the same composition (100 mmol/l KCl with Ca2+ added), with irradiation time being 20-30 min. Therefore, due to the exposure to the field the solution acquires some new properties that are important for the channel activity. The irradiation terminated, the solution retains a new state for at least 10-20 min (solution memory). The data suggest that the effects of the field on the channels are mediated, at least partially, by changes in the solution properties.

  13. Magnetocapacitance oscillations and thermoelectric effect in a two-dimensional electron gas irradiated by microwaves

    NASA Astrophysics Data System (ADS)

    Levin, A. D.; Gusev, G. M.; Raichev, O. E.; Momtaz, Z. S.; Bakarov, A. K.

    2016-07-01

    To study the influence of microwave irradiation on two-dimensional electrons, we apply a method based on capacitance measurements in GaAs quantum well samples where the gate covers a central part of the layer. We find that the capacitance oscillations at high magnetic fields, caused by the oscillations of thermodynamic density of states, are not essentially modified by microwaves. However, in the region of fields below 1 T, we observe another set of oscillations, with the period and the phase identical to those of microwave-induced resistance oscillations. The phenomenon of microwave-induced capacitance oscillations is explained in terms of violation of the Einstein relation between conductivity and the diffusion coefficient in the presence of microwaves, which leads to a dependence of the capacitor charging on the anomalous conductivity. We also observe microwave-induced oscillations in the capacitive response to periodic variations of external heating. These oscillations appear due to the thermoelectric effect and are in antiphase with microwave-induced resistance oscillations because of the Corbino-like geometry of our experimental setup.

  14. Low Temperature Synthesis of Carbon Nanotubes by Direct Microwave Irradiation

    DTIC Science & Technology

    2007-08-09

    REPORT DATE 09 AUG 2007 2. REPORT TYPE FInal 3. DATES COVERED 09-05-2005 to 08-11-2005 4. TITLE AND SUBTITLE Microwave synthesis of nano ...after completing the analysis of synthesized CNTs. 15. SUBJECT TERMS Nanotechnology, Carbon nano tubes 16. SECURITY CLASSIFICATION OF: 17...compounds such as thiophene, and sulfur was detected as a sulfide phase from the catalyst surface even in micro -contents. In our experiments, Y-junction

  15. Direct conversion of cellulose to 1-(furan-2-yl)-2-hydroxyethanone in zinc chloride solution under microwave irradiation.

    PubMed

    Yang, Lei; Li, Gang; Yang, Fang; Zhang, Song-Mei; Fan, Hong-Xian; Lv, Xiao-Na

    2011-10-18

    Conversion of cellulose to 1-(furan-2-yl)-2-hydroxyethanone has been demonstrated in concentrated zinc chloride solution under microwave irradiation. Compared with the conventional oil-bath heating mode, microwave irradiation significantly reduced the reaction time and increased the yield of 1-(furan-2-yl)-2-hydroxyethanone. A typical degradation reaction with cellulose produced 1-(furan-2-yl)-2-hydroxyethanone in 12.0% molar yield in ZnCl(2) solution (ZnCl(2)-H(2)O ratio=2.25:1, w/w) with microwave irradiation at 600 W for 5 minutes at 135°C.

  16. A Comparative Study Between Microwave Irradiation and Sodium Hypochlorite Chemical Disinfection: A Prosthodontic View

    PubMed Central

    Goel, Kashish; Gupta, Rupesh; Solanki, Jitender

    2014-01-01

    Background: Prosthodontic procedures involving dental impressions, stone casts, record bases and prostheses may cause transmission of microorganisms between the patient, the dentist, auxiliary staff and laboratory personnel. In recent times, microwave radiation has gained wider acceptance in the field of applied science and has been used to reduce concentrations of bacteria and fungi, to dry dental casts,and to sterilize preparation media. Objective: This in-vitro study was conducted to compare microwave irradiation and 0.07% sodium hypochlorite chemical disinfection. The study also evaluated the effect of microwave irradiation and 0.07% sodium hypochlorite chemical disinfection on the dimensional stability of Kalstone casts. Materials and Methods: Forty impressions were made and divided into two groups of 20 each. Each group was contaminated with Staphylococcus aureus and Pseudomonas aeruginosa respectively. Each impression was divided into three parts and marked A, B, C. Impressions were then poured in kalastone. Part A of 20 kalastone casts were microwave disinfected, and Part B were chemically disinfected (0.07% NaOCl) while Part C were not disinfected and used as control. Results: On comparing the significant difference was seen in the microbial load between microwave and chemical disinfection (Z=56.480; p<0.001). Conclusion: On the basis of observations made for the antimicrobial assessment the microwave irradiated Kala stone casts proved to be a better disinfection method when compared with 0.07% sodium hypochlorite chemically disinfected incorporated cast. No significant difference was seen in the dimensional stability of Kala stone discs. PMID:24959515

  17. Growth and development of mice offspring after irradiation in utero with 2,450-MHz microwaves

    SciTech Connect

    Berman, E.; Carter, H.B.; House, D.

    1984-12-01

    Mice offspring irradiated in utero with 2,450-MHz radio-frequency (RF) radiation at 0 or 28 mW/cm2 (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, 5, 10, 12, 15, and 17 of age. The tests used to determine differences in developmental age in the two treatment groups were body weight, urine concentrating ability, brain weight, tolerance to ouabain, and bone lengths. Fifteen sham-irradiated and 26 RF-irradiated litters, normalized to eight pups/litter, were used in this study. Mean body weight of the microwave-irradiated offspring were significantly (p . .0003) decreased only on day 1 of age. Brain weight on days 10, 12, and 17 were significantly lower in microwave-irradiated pups (p . .01). There were no significant differences in the two groups in urine concentrating ability on day 5, ouabain tolerance on day 15, or bone length on days 5, 10, 12, and 17. It is concluded that there is a persistent delay in postnatal development of the brain after RF irradiation with 16.5 W/kg during gestation.

  18. An efficient protocol for the solid-phase synthesis of glycopeptides under microwave irradiation.

    PubMed

    Garcia-Martin, Fayna; Hinou, Hiroshi; Matsushita, Takahiko; Hayakawa, Shun; Nishimura, Shin-Ichiro

    2012-02-28

    A standardized and smooth protocol for solid-phase glycopeptides synthesis under microwave irradiation was developed. Double activation system was proved to allow for highly efficient coupling of Tn-Ser/Thr and bulky core 2-Ser/Thr derivatives. Versatility and robustness of the present strategy was demonstrated by constructing a Mucine-1 (MUC1) fragment and glycosylated fragments of tau protein. The success of this approach relies on the combination of microwave energy, a resin consisting totally of polyethylene glycol, a low excess of sugar amino acid and the "double activation" method.

  19. Microwave-Irradiation-Assisted HVAC Filtration for Inactivation of Viral Aerosols (Postprint)

    DTIC Science & Technology

    2012-02-01

    processing, wood drying, plastic and rubber treating, curing and preheating ceramics as well as in cleanup processes (Park et al., 2006). Microwaves...applying microwave irradiation to airborne bacteria and fungi at 600 W for four periods of 2.5 min, each separated by 5 min from the next. Elhafi et...dried swabs in less than 20 s at 1250 W. In another study, Wu and Yao (2010a) reported IEs of 65% and 6% against airborne B. subtilis var niger spore

  20. Microstructural Characterization of Cermet Cladding Developed Through Microwave Irradiation

    NASA Astrophysics Data System (ADS)

    Gupta, Dheeraj; Sharma, Apurbba Kumar

    2012-10-01

    In the present work, cladding of hardfacing WC10Co2Ni powder on austenitic stainless steel has been developed through a novel processing technique. The clads were developed using microwave hybrid heating. The clad of average thickness ~2 mm has been developed through the exposure of microwave radiation at frequency 2.45 GHz and power 900 W for the duration of 360 s. The developed clads were characterized using field emission scanning electron microscope, X-ray elemental analysis, X-ray diffraction, and measurement of Vicker's microhardness. The microstructure study of the clad showed good metallurgical bonding with substrate and revealed that clads are free from any visible interface cracking. Clads were formed with partial dilution of a thin layer of the substrate. The cermet microstructure mainly consists of relatively soft metallic matrix phase and uniformly distributed hard carbide phase with skeleton-like structure. The developed clads exhibit an average microhardness of 1064 ± 99 Hv. The porosity of developed clad has been significantly less at approximately 0.89%.

  1. Dissecting competitive mechanisms: thionation vs. cycloaddition in the reaction of thioisomunchnones with isothiocyanates under microwave irradiation.

    PubMed

    Cantillo, David; Avalos, Martín; Babiano, Reyes; Cintas, Pedro; Jiménez, José L; Light, Mark E; Palacios, Juan C

    2009-10-16

    This paper documents in detail the reaction of 1,3-thiazolium-4-olates (thioisomunchnones) with aryl isothiocyanates. Having demonstrated with a chiral model that thionation occurs under these conditions to provide 1,3-thiazolium-4-thiolates and that this process is actually a stepwise domino reaction (J. Org. Chem. 2009, 74, 3698-3705), we extend this study to monocyclic thioisomunchnones. Herein, competition between thionation and 1,3-dipolar cycloaddition takes place. The process is synthetically disappointing at room temperature requiring prolonged reaction times for completion. The protocol has been subsequently investigated by using both microwave dielectric heating and conventional thermal heating (oil bath) in DMF at 100 degrees C with an accurate internal reaction temperature measurement. Although a slight acceleration was observed for reactions conducted under microwave irradiation, for most cases the observed yields and chemoselectivities were quite similar. Thus one can conclude that, within experimental errors, the reactivity is not related to nonthermal effects in agreement with recent reassessments on this subject, particularly by Kappe and associates (J. Org. Chem. 2008, 73, 36; J. Org. Chem. 2009, 74, 6157). The whole reaction system, which includes numerous heavy atoms, can be computationally modeled with a hybrid ONIOM[B3LYP/6-31G(d):PM3] level. This reproduces well experimental results and suggests a sequential mechanism. To further corroborate the nonconcertedness, the potential energy surface (PES) has been constructed for simplified models, locating the corresponding stationary points. In doing so, we introduce for the first time a useful and convenient mathematical protocol to locate the stationary points along a reaction path. The protocol is quite simple and should convince many organic chemists that certain daunting theoretical treatments can be made easy.

  2. Rapid synthesis of antimicrobial paper under microwave irradiation.

    PubMed

    kamel, Samir

    2012-11-06

    The silver-nanoparticle (AgNP) containing paper was successfully prepared. The AgNP is deposited by the in situ reduction of silver nitrate on the acrylamide grafted bagasse paper sheets in the presence of citrate molecules as stabilizing agent. In the present paper, grafting of acrylamide onto bagasse paper sheets using potassium persulfate was carried out under the influence of microwave radiations (MWR). The modified paper sheets were characterized by Fourier transform infrared spectroscopy (FTIR), UV-spectroscopy, and scanning electron microscopy (SEM). Antimicrobial activities of the prepared paper sheets were also investigated against G+ve bacterium Staphylococcus aureus, G-ve bacterium Pseudomomas aeruginosa, and yeast Candida albicans, which are model microorganisms for testing bactericidal properties. The AgNP containing paper sheets exhibited antibacterial activity.

  3. 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...

  4. 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...

  5. Microwave effect in the fast synthesis of microporous materials: which stage between nucleation and crystal growth is accelerated by microwave irradiation?

    PubMed

    Jhung, Sung Hwa; Jin, Taihuan; Hwang, Young Kyu; Chang, Jong-San

    2007-01-01

    Microporous materials, such as silicalite-1 and VSB-5 molecular sieves, have been synthesized by both microwave irradiation (MW) and conventional electric heating (CE). The accelerated syntheses by microwave irradiation can be quantitatively investigated by various heating modes conducted in two steps such as MW-MW, MW-CE, CE-MW, and CE-CE (in the order of nucleation-crystal growth). In the case of synthesis by MW-CE or CE-MW, the heating modes were changed for the second step just after the appearance of X-ray diffraction peaks in the first step. We have quantitatively demonstrated that the microwave irradiation accelerates not only the nucleation but also crystal growth. However, the contribution to decrease the synthesis time by microwave irradiation is larger in the nucleation stage than in the step of crystal growth. The crystal size increases in the order of MW-MWmicrowave-nucleated precursor can be explained in terms of the fact that the microwave-nucleated samples have higher population of nuclei with smaller size than the samples nucleated by conventional heating.

  6. Tissue structure of rat brain after microwave irradiation using maximum magnetic field component.

    PubMed

    Ikarashi, Y; Okada, M; Maruyama, Y

    1986-05-14

    A novel microwave instrument has recently been designed by New Japan Radio Co. Ltd., to provide more homogeneous distribution of the rapidly deposited heat in the rodent brain. Being the first commercial unit which concentrates the maximum magnetic field component of irradiation, rather than the usual electric field, it provides complete enzymatic inactivation in a typical rat brain when a power of 9 kW (90% of maximum) is applied for 0.80 s at the standard operating frequency of 2450 MHz. Tissue structural integrity was investigated in animals sacrificed by this approach or by the usual decapitation to see if any tissue disruption or pressure-induced spreading, a major problem with other microwave devices, might also be of concern for this new unit. Histological examination of tissue samples employed both light and electron microscopy. Using Luxol Fast Blue in the light microscopy, the microwave irradiated tissues exhibited a decreased affinity for the staining agent, an appearance of slight vacuoles, and the disappearance of fine fibrils in the parenchyma. However, the interfacial areas between distinct brain regions remained well preserved. Electron microscopic observation indicated that microwave irradiated tissue caused protein denaturation accompanied by the aggregation of nuclear chromatin, the disappearance of Nissl bodies, ribosomes and neurofilaments, and noticeably irregular myelin sheaths. However, the essential structure of nerve cell membranes and synaptic membranes were maintained, and synaptic vesicles were clearly defined. These results indicated that the rapid heating of brain tissue with maximal magnetic field concentration of the irradiation does not result in significant tissue disruption, pressure-induced spreading or cell breakdown.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. 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

  8. In Situ Free Radical Growth Mechanism of Platinum Nanoparticles by Microwave Irradiation and Electrocatalytic Properties

    NASA Astrophysics Data System (ADS)

    Inwati, Gajendra Kumar; Rao, Yashvant; Singh, Man

    2016-10-01

    Microwave irradiation was employed for spherical-shaped platinum nanoparticle (Pt NPs) preparation. Spherical Pt NPs indexed with (111) facets were prepared using Pt(II) precursor salt, glycerol as solvent and reducing agent, and polyvinylpyrrolidone (PVP) as a shape directer under microwave irradiation for 3-5 min at 300 °C. Electron spin resonance (ESR) peak at 336.000 mT (milli Tesla) confirmed the free radical formation from aqueous glycerol solution which acted as reducing species under microwave. The 2-8-nm diameter of particles was obtained by high-resolution transmission electron microscope. Dynamic light scattering was used to optimize the microwave dose followed by 33 and 48 nm size and 51 and 67 mV zeta potential of Pt NPs, respectively. The PVP was demonstrated as shape controlling agent investigated by Fourier transmission infrared spectroscopy (FTIR). The electrocatalytic performance of as-prepared Pt colloids was investigated using cyclic voltammetry which showed a higher catalytic activity for ethanol redox reaction.

  9. High-molecular-weight poly(Gly-Val-Gly-Val-Pro) synthesis through microwave irradiation.

    PubMed

    Goto, Mitsuaki; Endo, Takeshi

    2016-07-01

    In this study, we synthesized a polypeptide from its pentapeptide unit using microwave irradiation. Effective methods for polypeptide synthesis from unit peptides have not been reported. Here, we used a key elastin peptide, H-GlyValGlyValPro-OH (GVGVP), as the monomer peptide. It is difficult to obtain poly(Gly-Val-Gly-Val-Pro) (poly(GVGVP)) from the pentapeptide unit of elastin, GVGVP, via polycondensation. Poly(GVGVP) prepared from genetically recombinant Escherichia coli is a well-known temperature-sensitive polypeptide, and this temperature sensitivity is known as the lower critical solution temperature. When microwave irradiation was performed in the presence of various additives, the pentapeptide (GVGVP) polycondensation reaction proceeded smoothly, resulting in a product with a high molecular weight in a relatively good yield. The reaction conditions, like microwave irradiation, coupling agents, and solvents, were optimized to increase the reaction efficiency. The product exhibited a molecular weight greater than Mr 7000. Further, the product could be synthesized on a gram scale. The synthesized polypeptide exhibited a temperature sensitivity that was similar to that of poly(GVGVP) prepared from genetically recombinant E. coli. Therefore, this technique offers a facile and quick approach to prepare polypeptides in large amounts. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.

  10. Antigen recovery and preservation using the microwave irradiation of biological samples for transmission electron microscopy analysis.

    PubMed

    Aïoun, Josiane; Chat, Sophie; Bordat, Christian; Péchoux, Christine

    2013-01-01

    Most studies using microwave irradiation (MWI) for the preparation of tissue samples have reported an improvement in structural integrity. However, there have been few studies on the effect of microwave (MW) on antigen preservation during sample preparation prior to immunolocalization. This report documents our experience of specimen preparation using an automatic microwave apparatus to obtain antigen preservation and retrieval. We tested the effects of MW processing vs. conventional procedures on the morphology and antigenicity of two different tissues: the brain and mammary gland, whose chemical composition and anatomical organization are quite different. We chose to locate the transcription factor PPARβ/δ using immunocytochemistry on brain tissue sections from hamsters. Antigen retrieval protocols involving MWI were used to restore immunoreactivity. We also studied the efficiency of the ultrastructural immunolocalization of both PPARγ and caveolin-1 following MWI vs. conventional treatment, on mammary gland tissue from mice at 10 days of lactation. Our findings showed that the treatment of tissue samples with MWI, in the context of a process lasting just a few hours from fixation to immunolocalization, enabled similar, or even better, results than conventional protocols. The quantification of immunolabeling for cav-1 indicated an increase in density of up to three-fold in tissues processed in the microwave oven. Furthermore, MW treatment permitted the localization of PPARβ/δ in glutaraldehyde-fixed specimens, which was impossible in the absence of MWI. This study thus showed that techniques involving the use of microwaves could largely improve both ultrastructure and immunodetection.

  11. Photonic microwave signals with zeptosecond-level absolute timing noise

    NASA Astrophysics Data System (ADS)

    Xie, Xiaopeng; Bouchand, Romain; Nicolodi, Daniele; Giunta, Michele; Hänsel, Wolfgang; Lezius, Matthias; Joshi, Abhay; Datta, Shubhashish; Alexandre, Christophe; Lours, Michel; Tremblin, Pierre-Alain; Santarelli, Giorgio; Holzwarth, Ronald; Le Coq, Yann

    2017-01-01

    Photonic synthesis of radiofrequency (RF) waveforms revived the quest for unrivalled microwave purity because of its ability to convey the benefits of optics to the microwave world. In this work, we perform a high-fidelity transfer of frequency stability between an optical reference and a microwave signal via a low-noise fibre-based frequency comb and cutting-edge photodetection techniques. We demonstrate the generation of the purest microwave signal with a fractional frequency stability below 6.5 × 10-16 at 1 s and a timing noise floor below 41 zs Hz-1/2 (phase noise below -173 dBc Hz-1 for a 12 GHz carrier). This outperforms existing sources and promises a new era for state-of-the-art microwave generation. The characterization is achieved through a heterodyne cross-correlation scheme with the lowermost detection noise. This unprecedented level of purity can impact domains such as radar systems, telecommunications and time-frequency metrology. The measurement methods developed here can benefit the characterization of a broad range of signals.

  12. Device for timing and power level setting for microwave applications

    NASA Astrophysics Data System (ADS)

    Ursu, M.-P.; Buidoş, T.

    2016-08-01

    Nowadays, the microwaves are widely used for various technological processes. The microwaves are emitted by magnetrons, which have strict requirements concerning power supplies for anode and filament cathodes, intensity of magnetic field, cooling and electromagnetic shielding. The magnetrons do not tolerate any alteration of their required voltages, currents and magnetic fields, which means that their output microwave power is fixed, so the only way to alter the power level is to use time-division, by turning the magnetron on and off by repetitive time patterns. In order to attain accurate and reproducible results, as well as correct and safe operation of the microwave device, all these requirements must be fulfilled. Safe, correct and reproducible operation of the microwave appliance can be achieved by means of a specially built electronic device, which ensures accurate and reproducible exposure times, interlocking of the commands and automatic switch off when abnormal operating conditions occur. This driving device, designed and realized during the completion of Mr.Ursu's doctoral thesis, consists of a quartz time-base, several programmable frequency and duration dividers, LED displays, sensors and interlocking gates. The active and passive electronic components are placed on custom-made PCB's, designed and made by means of computer-aided applications and machines. The driving commands of the electronic device are delivered to the magnetron power supplies by means of optic zero-passing relays. The inputs of the electronic driving device can sense the status of the microwave appliance. The user is able to enter the total exposure time, the division factor that sets the output power level and, as a novelty, the clock frequency of the time divider.

  13. Preparation and structural characterization of poly-mannose synthesized by phosphoric acid catalyzation under microwave irradiation.

    PubMed

    Wang, Haisong; Cheng, Xiangrong; Shi, Yonghui; Le, Guowei

    2015-05-05

    Poly-mannose with molecular weight of 2.457 kDa was synthesized using d-mannose as substrate and phosphoric acid as catalyst under the condition of microwave irradiation for the first time. The optimum reaction conditions were microwave output power of 900 W, temperature 115°C, proton concentration 2.5 mol/L, and microwave irradiation time 5 min. The actual maximum yield was 91.46%. After purified by Sepherdex G-25 column chromatography, the structural features of poly-mannose were investigated by high-performance anion-exchange chromatography (HPAEC), high-performance gel-permeation chromatography (HPGPC), infrared (IR) spectroscopy, methylation analysis and NMR spectroscopy analysis ((1)H, (13)C, COSY, TOCSY, HMQC, and HMBC). HPAEC analysis showed that the composition of synthetic polysaccharides was d-mannose, its purity was demonstrated by HPGPC as a single symmetrical sharp peak, and additionally IR spectra demonstrated the polymerization of d-mannose. Methylation analysis and NMR spectroscopy revealed that the backbone of poly-mannose consisting of (1→3)-linked β-d-Manp, (1→3)-linked α-d-Manp, and (1→6)-linked α-d-Manp residues, and the main chain were branched at the O-2, O-3, O-4, O-6 position.

  14. Preparation of Cu-Ni/YSZ solid oxide fuel cell anodes using microwave irradiation

    NASA Astrophysics Data System (ADS)

    Islam, Shamiul; Hill, Josephine M.

    A microwave irradiation process is used to deposit Cu nanoparticles on the Ni/YSZ anode of an electrolyte-supported solid oxide fuel cell (SOFC). The reaction time in the microwave is only 15 s for the deposition of 6 wt% Cu (with respect to Ni) from a solution of Cu(NO 3) 2·3H 2O and ethylene glycol (HOCH 2CH 2OH). The morphology of the deposited Cu particles is spherical and the average size of the particles is less than 100 nm. The electrochemical performance of the microwave Cu-coated Ni/YSZ anodes is tested in dry H 2 and dry CH 4 at 1073 K, and the anodes are characterized with scanning electron microscopy, electrochemical impedance spectroscopy, and temperature-programmed oxidation. The results indicate that preparation of the anodes by the microwave technique produces similar performance trend as those reported for Cu-Ni/YSZ/CeO 2 anodes prepared by impregnation. Specifically, less carbon is formed on the Cu-Ni/YSZ than on conventional Ni/YSZ anodes when exposed to dry methane and the carbon that does form is more reactive.

  15. Temperature of denture base resin under different protocols of microwave irradiation.

    PubMed

    Sesma, Newton; Gil, Carlos; Kolikauskas, William Antunes; Silva, Rafael Andrade; Pannuti, Claudio Mendes

    2011-01-01

    This in vitro study evaluated the temperature of dentures after different microwave irradiation protocols. Two complete dentures (one maxillary and one mandibular denture) were irradiated separately 4 times for each of the following 5 protocols: dentures immersed in water (G1- 6 min, G2- 3 min); dentures kept dry (G3- 6 min); dentures placed in the steam sterilizer (G4- 6 min, G5- 3 min). The final temperature of the dentures was gauged in a thin and in a thick area of each denture with an infrared thermometer. All groups presented an increase in the resin base temperature. The thin areas of the dentures underwent greater heating than the thick areas. There was no significant difference (p>0.05) between the final mean temperatures of dentures immersed in water for 6 (G1) and 3 min (G2). However, the final mean temperatures recorded in G1 and G2 exceeded 71°C and were significantly higher (<0.001) than the final mean temperatures recorded in the other groups. It may be concluded that denture base resins subjected to microwave irradiation immersed in water may be exposed to deleterious temperatures.

  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.

  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.

  18. ALTERNATIVE ROUTES FOR CATALYST PREPARATION: USE OF ULTRASOUND AND MICROWAVE IRRADIATION FOR THE PREPARATION OF VANADIUM PHOSPHORUS OXIDE CATALYST AND THEIR ACTIVITY FOR HYDROCARBON OXIDATION

    EPA Science Inventory

    Vanadium phosphorus oxide (VPO) has been prepared using ultrasound and microwave irradiation methods and compared with the catalyst prepared by conventional method for both the phase composition and activity for hydrocarbon oxidation. It is found that ultrasound irradiation metho...

  19. Electron thermalization and attachment in pulse-irradiated oxygen studied by time-resolved microwave conductivity

    NASA Astrophysics Data System (ADS)

    Warman, John M.; Cooper, Ronald

    The microwave conductivity of oxygen gas following nanosecond pulsed irradiation has been studied for pressures from 5 to 50 torr. The conductivity is found to decrease by a factor of approx. 20 in the early stages ( tN < 2 x 10 11 s cm -3) following the pulse. This is attributed to a decrease in the electron collision frequency as the initial excess energy of the electrons becomes degraded. A further decrease found at longer times is due to the three-body attachment of electrons to O 2 with a rate constant of 2.4 x 10 -30 cm 6s -1. Above a pressure of approx. 30 torr significant attachment begins to occur while electrons are still superthermal. The time at which the microwave signal is within 10% of the value corresponding to thermal energies is given by τ thP ≈ 15 μs.torr.

  20. Microwave irradiation--A green and efficient way to pretreat biomass.

    PubMed

    Li, Hongqiang; Qu, Yongshui; Yang, Yongqing; Chang, Senlin; Xu, Jian

    2016-01-01

    As a non-traditional heating way, microwave irradiation (MWI) has long been used for lignocellulose pretreatment with the advent of commercial microwave oven since the 1970s. MWI pretreatment using MWI as heating source is similar to other pretreatment methods. Although MWI pretreatment solves some problems caused by other pretreatment methods, such as low heating rate and thermal efficiency, uneven heating, it brings some new challenges such as reaction vessel selection and pretreatment process design. Over 30 years of development, researchers have achieved good pretreatment performance with MWI which has been applied gradually from laboratory scale to pilot-scale. It should be noted that MWI pretreatment is facing some problems: high cost of pretreatment, short of large-scale equipment, the non-thermal effects in pretreatment is still controversial. If MWI pretreatment reaction mechanism could be further clarified and large-scale industrialized reactor be designed, MWI pretreatment might be widely used in biorefinery.

  1. Water-soluble loratadine inclusion complex: analytical control of the preparation by microwave irradiation.

    PubMed

    Nacsa, A; Ambrus, R; Berkesi, O; Szabó-Révész, P; Aigner, Z

    2008-11-04

    The majority of active pharmaceutical ingredients are poorly soluble in water. The rate-determining step of absorption is the dissolution of these drugs. Inclusion complexation with cyclodextrin derivatives can lead to improved aqueous solubility and bioavailability of pharmacons due to the formation of co-crystals through hydrogen-bonding between the components. Inclusion complexes of loratadine were prepared by a convenient new method involving microwave irradiation and the products were compared with those of a conventional preparation method. Dissolution studies demonstrated that the solubility and rate of dissolution of loratadine increased in both of the methods used. The interactions between the components were investigated by thermal analysis and Fourier Transform Infrared studies. The microwave treatment did not cause any chemical changes in the loratadine molecule.

  2. Effect of e-beam irradiation and microwave heating on the fatty acid composition and volatile compound profile of grass carp surimi

    NASA Astrophysics Data System (ADS)

    Zhang, Hongfei; Wang, Wei; Wang, Haiyan; Ye, Qingfu

    2017-01-01

    In this study, we evaluated the effects of e-beam irradiation(1-7 kGy) and irradiation coupled to microwave heating (e-I-MC, 70 °C internal temperature) on the fatty acid composition and volatile compound profile of grass carp surimi. Compared to control samples, e-beam irradiation generated three novel volatile compounds (heptane, 2,6-dimethyl-nonane, and dimethyl disulfide) and increased the relative proportions of alcohols, aldehydes, and ketones. Meanwhile, e-I-MC significantly increased aldehyde levels and generated five heterocyclic compounds along with these three novel compounds. No significant difference in volatile compounds were detected in e-I-MC samples with increasing irradiation dose (p>0.05), comparing to the control group. E-beam irradiation at 5 and 7 kGy increased the levels of saturated fatty acids (SFAs) and decreased the levels of unsaturated fatty acids (p≤0.05), but did not affect the content of trans fatty acid levels (p>0.05). Irradiation, which had no significant effects on (Eicosapentaenoic acid) EPA, decreased (Docose Hexaenoie Acid) DHA levels. In the e-I-MC group, SFA levels increased and PUFA levels decreased. Additionally, MUFA levels were unaffected and trans fatty acid levels increased slightly following e-I-MC.

  3. 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

  4. Degradation of 4-chlorophenol by microwave irradiation enhanced advanced oxidation processes.

    PubMed

    Zhihui, Ai; Peng, Yang; Xiaohua, Lu

    2005-08-01

    In this work the synergistic effects of several microwave assisted advanced oxidation processes (MW/AOPs) were studied for the degradation of 4-chlorophenol (4-CP). The efficiencies of the degradation of 4-CP in dilute aqueous solution for a variety of AOPs with or without MW irradiation were compared. The results showed that the synergistic effects between MW and H2O2, UV/H2O2, TiO2 photocatalytic oxidation (PCO) resulted in a high degradation efficiency for 4-CP. The potential of MW/AOPs for treatment of industrial wastewater is discussed.

  5. Soft-mold-induced self-construction of polymer patterns under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Ko, Fu-Hsiang; Wu, Chia-Tien; Chen, Mei-Fen; Chen, Jem-Kun; Chu, Tieh-Chi

    2007-05-01

    In this study, the authors used a soft-mold-induced self-construction method to fabricate three-dimensional patterns under microwave irradiation for 1min. The authors estimated the actual pattern growth temperature using a fluorescence probe technique. The temperature at which pattern growth originated was, by necessity, higher than the glass transition temperature of the novolak resist. Electrostatic forces and surface tension effects under the electromagnetic field contributed significantly to the pattern growth, and the use of an antisticking agent allowed easy demolding.

  6. Enaminones in heterocyclic synthesis: a novel route to tetrahydropyrimidines, dihydropyridines, triacylbenzenes and naphthofurans under microwave irradiation.

    PubMed

    Al-Mousawi, Saleh Mohammed; El-Apasery, Morsy Ahmed; Elnagdi, Mohamed H

    2009-12-25

    Condensation of phthalimidoacetone (1) with DMFDMA (N,N-Dimethylformamide dimethyl acetal) has afforded enaminone 2. Refluxing 2 with equimolecular amounts of benzaldehyde and urea in acetic acid afforded a mixture of tetrahydropyrimidine 5 and the dihydropyridine 6. Compound 2 undergoes self-condensation on heating in acetic acid or under microwave irradiation in presence of acidic zeolite to give 1,3,5-triacylbenzene 9. Reacting enaminone 11a with naphthoquinone 15 afforded the naphthofuran 18. The possible formation of the aldehyde 19 was excluded based on an HMQC experiment, which revealed that the carbonyl carbon is not linked to any hydrogen.

  7. Evaluation and Comparison of High-Level Microwave Oven Disinfection with Chemical Disinfection of Dental Gypsum Casts

    PubMed Central

    Meghashri, K; Kumar, Prasanna; Prasad, D Krishna; Hegde, Rakshit

    2014-01-01

    Background: The aim of this study was to evaluate and compare microwave disinfection with chemical disinfection of dental gypsum casts. Materials and Methods: A total of 120 casts were prepared from a silicone mold using Type III dental stone. Of the 120 casts, 60 casts were contaminated with 1 ml suspension of Staphylococcus aureus and 60 casts were contaminated with 1 ml suspension of Pseudomonas aeruginosa. Then, the casts were disinfected with microwave irradiation and chemical disinfection using the microwave oven and 0.5% sodium hypochlorite. Bacteriologic procedures were performed; the cfu/ml for each cast was calculated as a weighted mean. The results were analyzed using Kruskal-Wallis test and Mann-Whitney test. Results: The untreated casts showed Brain heart infusion broth counts of 106 log cfu/ml compared to irradiated and chemically disinfected casts, in which 105 log reduction of cfu/ml was seen. These results satisfied the requirements of current infection control guidelines for the dental laboratory. The results obtained for chemical disinfection were in equivalence with microwave disinfection. Conclusions: Within the limitation of this in vitro study, it was found that microwave disinfection of casts for 5 min at 900 W gives high-level disinfection that complies with the current infection control guidelines for the dental laboratory and microwave disinfection method is an effective and validated method as chemical disinfection. How to cite the article: Meghashri K, Kumar P, Prasad DK, Hegde R. Evaluation and comparison of high-level microwave oven disinfection with chemical disinfection of dental gypsum casts. J Int Oral Health 2014;6(3):56-60 . PMID:25083033

  8. 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.

  9. Effects of acute low-level microwaves on pentobarbital-induced hypothermia depend on exposure orientation

    SciTech Connect

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

    1984-01-01

    Two series of experiments were performed to study the effects of acute exposure (45 min) to 2,450-MHz circularly polarized, pulsed microwaves (1 mW/cm2, 2-mus pulses, 500 pps, specific absorption rate (SAR) 0.6 W/kg) on the actions of pentobarbital in the rat. In the first experiment, rats were irradiated with microwaves and then immediately injected with pentobarbital. Microwave exposure did not significantly affect the extent of the pentobarbital-induced fall in colonic temperature. However, the rate of recovery from the hypothermia was significantly slower in the microwave-irradiated rats and they also took a significantly longer time to regain their righting reflex. In a second experiment, rats were first anesthetized with pentobarbital and then exposed to microwaves with their heads either pointing toward the source of microwaves (anterior exposure) or pointing away (posterior exposure). Microwave radiation significantly retarded the pentobarbital-induced fall in colonic temperature regardless of the orientation of exposure. However, the recovery from hypothermia was significantly faster in posterior-exposed animals compared to those of the anterior-exposed and sham-irradiated animals. Furthermore, the posterior-exposed rats took a significantly shorter time to regain their righting reflex than both the anterior-exposed and sham-irradiated animals.

  10. Optimization of resistant starch formation from high amylose corn starch by microwave irradiation treatments and characterization of starch preparations.

    PubMed

    Mutlu, Selime; Kahraman, Kevser; Öztürk, Serpil

    2017-02-01

    The effects of microwave irradiation on resistant starch (RS) formation and functional properties in high-amylose corn starch, Hylon VII, by applying microwave-storing cycles and drying processes were investigated. The Response Surface Methodology (RSM) was used to optimize the reaction conditions, microwave time (2-4min) and power (20-100%), for RS formation. The starch:water (1:10) mixtures were cooked and autoclaved and then different microwave-storing cycles and drying (oven or freeze drying) processes were applied. The RS contents of the samples increased with increasing microwave-storing cycle. The highest RS (43.4%) was obtained by oven drying after 3 cycles of microwave treatment at 20% power for 2min. The F, p (<0.05) and R(2) values indicated that the selected models were consistent. Linear equations were obtained for oven-dried samples applied by 1 and 3 cycles of microwave with regression coefficients of 0.65 and 0.62, respectively. Quadratic equation was obtained for freeze-dried samples applied by 3 cycles of microwave with a regression coefficient of 0.83. The solubility, water binding capacity (WBC) and RVA viscosity values of the microwave applied samples were higher than those of native Hylon VII. The WBC and viscosity values of the freeze-dried samples were higher than those of the oven-dried ones.

  11. 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

    2016-05-04

    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.

  12. Graft polymerization of guar gum with acryl amide irradiated by microwaves for colonic drug delivery.

    PubMed

    Shahid, Muhammad; Bukhari, Shazia Anwer; Gul, Yousra; Munir, Hira; Anjum, Fozia; Zuber, Mohammad; Jamil, Tahir; Zia, Khalid Mahmood

    2013-11-01

    This article is aimed to discuss the modification of guar gum through microwave irradiation by varying the time of irradiation. The characterization of the modified products was carried out using FTIR spectroscopic analysis. The FT-IR spectrum of the pure guar gum (GG) sample showed a broad peak at 3298 cm(-1) while the modified GG sample displayed a peak at 1541 cm(-1) which was absent in the crude sample. The X-ray diffraction (XRD) analysis confirmed the increase in crystallinity due to grafting of the sample with polyacrylamide (GG-g-PAM). Scanning electron microscope (SEM) images revealed that granular form of guar gum was changed into fibrillar structure after grafting. Thermo-gravimetric analysis of the modified samples was also carried out and discussed. The role of guar gum as a matrix for controlled release of drug triamcinolone was evaluated. The GG-acrylamide grafted samples presented a correlation between drug release and time of microwave exposure. The results revealed that such modified product has potential applications in colonic drug delivery system.

  13. 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.

  14. Effect of microwave irradiation on the molecular and structural properties of hyaluronan.

    PubMed

    Bezáková, Zuzana; Hermannová, Martina; Dřímalová, Eugenie; Malovíková, Anna; Ebringerová, Anna; Velebný, Vladimír

    2008-09-05

    Hyaluronan (Na(+) salt of hyaluronic acid, HA) was extensively depolymerised by HCl-catalyzed hydrolysis at pH 3 for up to 500min under temperature-controlled microwave irradiation. The effects of microwave heating on the hydrodynamic properties of the polysaccharide were determined by SEC-MALLS and viscometry. The weight-average molecular mass (Mw) of HA decreased from 1.44×10(6) to ∼5000, reaching the region of higher oligosaccharides. The scission of HA chains was found to proceed randomly during the whole degradation process. Treatment of the Mw and intrinsic viscosity data according to the Mark-Houwink equation, [η]=k×Mw(α) suggested three relationships with α1=0.46 for Mw>500,000, α2=0.84 for Mw between 500,000 and 50,000, and α3=1.13 for Mw<50,000. The results revealed that HA with Mw>10,000 adopts a stiffish coil conformation in solution. As monitored by FT-IR and NMR spectroscopic techniques, the primary structure of the HA chains was maintained during the microwave-assisted hydrolysis at pH 3 at 105°C. At reaction times larger than 240min, uv spectroscopy suggested the depolymerisation of HA was accompanied by formation of by-products produced by side reaction.

  15. Evaluation of effectiveness of microwave irradiation for disinfection of silicone elastomeric impression material.

    PubMed

    Bhasin, Abhilasha; Vinod, V; Bhasin, Vinny; Mathew, Xavier; Sajjan, Suresh; Ahmed, Syed Tauqheer

    2013-06-01

    Use of domestic microwave oven has been suggested as a method of disinfecting a number of dental materials used in dental practice. This study was done to analyse the effect of microwave irradiation on vinyl polysiloxane putty impression material (3M ESPE, Express™ STD) contaminated with test organisms (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans. 180 square shaped specimens of addition silicon putty material were prepared and divided into 3 groups for three test organisms. The 3 groups were subdivided into 4 subgroups (n = 15) for different exposure parameters (control group 5, 6 and 7 min exposure at 650 W. The specimens were contaminated using standard inoculums of test organism and then were irradiated using domestic microwaves. Broth cultures of the control and test group specimens were plated on selective media culture plates. Colonies formed were counted. Data analyses included Kruskal-Walli's ANOVA and Mann-Whitney's tests. Nil values shows complete elimination of C. albicans and P. aeruginosa after 5, 6 and 7 min exposure. Staphylococcus aureus showed colonies with the mean value of 7.6 × 10(3) ± 2.3 × 10(3), 4.6 × 10(3) ± 2.6 × 10(3) after 5 and 6 min respectively and nil values after 7 min exposure. 5 min exposure caused complete elimination of C. albicans and P. aeruginosa strains, while 7 min exposure eliminated S. aureus completely.

  16. Thin-layer liquid crystal thermometry of cells in vitro during hyperthermal microwave irradiation.

    PubMed

    Robinson, J E; McCulloch, D; Harrison, G H; Cheung, A Y

    1982-01-01

    A nonperturbing technique of thin-layer liquid crystal thermometry was developed to quantitate heating of Chinese hamster ovary cells and the bacterium Serratia marcescens when exposed to 2450-MHz microwave fields at 0.2-0.5 W/cm2. Cells suspended in culture medium were injected into 5-cm glass microcapillary tubes coated on the inside with a thin layer of liquid crystal. The tubes were sealed and placed parallel to the electric field in a watertight waveguide exposure chamber where they were heated by circulating temperature-controlled water. Even at high circulation rates, liquid crystal color changes indicated local microwave capillary tube heating of 0.1-0.25 degrees C. Precision of measurement was 0.02 degrees C. Observations during microwave heating were significantly different from observations without microwaves at the 1% level, and heating increased as circulating water flow was reduced from 300 ml/s to 100 ml/s. The results of a cell survival assay following hyperthermal treatment were in good agreement with expectations based on the observations of microwave heating using liquid crystals.

  17. Inclusion of fenofibrate in a series of mesoporous silicas using microwave irradiation.

    PubMed

    Waters, Laura J; Hussain, Talib; Parkes, Gareth; Hanrahan, John P; Tobin, Joseph M

    2013-11-01

    A selection of porous silicas were combined with a model drug using a recently developed, controlled microwave heating process to determine if the application of microwave irradiation could enhance subsequent drug release. Five mesoporous silica types were investigated (core shell, core shell rehydrox, SBA-15, silica gel, SYLOID®) and, for comparison, one non-porous silica (stober). These were formulated using a tailored microwave heating method at drug/excipient ratios of 1:1, 1:3 and 1:5. In addition, all experiments were performed both in the presence and absence of water, used as a fluidising media to aid interaction between drug and support, and compared with results obtained using more traditional heating methods. All formulations were then characterised using differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier transformation infrared spectroscopy (FT-IR). Pharmaceutical performance was investigated using in vitro drug release studies. A significant enhancement in the release profile of fenofibrate was observed for formulations prepared using microwave heating in the absence of water for five of the six silica based formulations. Of all the formulations analysed, the greatest extent of drug release within the experimental 30 min was the 1:5 core shell rehydrox achieving a total of 86.6 ± 2.8%. The non-porous (stober) particles did not exhibit an increased release of the drug under any experimental conditions studied. This anomaly is thought to be a result of the comparatively small surface area of the silica particles, thus preventing the adsorption of drug molecules.

  18. Low-temperature synthesis of allyl dimethylamine by selective heating under microwave irradiation used for water treatment

    NASA Astrophysics Data System (ADS)

    Tian, Binghui; Luan, Zhaokun; Li, Mingming

    2005-08-01

    Low-temperature synthesis of allyl dimethylamine (ADA) by selective heating under microwave irradiation (MI) used for water treatment is investigated. The effect of MI, ultrasound irradiation (UI) and conventional heating on yield of ADA, reaction time and the flocculation efficiency of polydiallyl dimethylammunion chloride (PDADMAC) prepared form ADA were studied. The results show that by selective heating at low temperature, MI not only increases yield of ADA and reduces reaction time, but also greatly enhances the flocculation efficiency of PDADMAC.

  19. 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

  20. Behavioral effects of chlorpromazine and diazepam combined with low-level microwaves. [Rats

    SciTech Connect

    Thomas, J.R.; Schrot, J.; Banvard, R.A.

    1980-01-01

    Previous research findings on the interaction between drugs and microwave radiation were extended to chlorpromazine and to diazepam. The drugs were combined with a 1 mW/cm/sub 2/ pulsed microwave field (2.8 GHz) and effects were measured on a fixed interval (FI 1) schedule of food reinforcement with rats. Dose-effect functions with and without sham irradiation were established for each drug. At effective doses chlorpromazine consistently decreased rate of responding and reduced with-interval response patterning. Low to moderate doses of diazepam produced little change or increases in response rate, and higher doses produced a decline in response rate. Response patterning within intervals was reduced by increasing doses of diazepam. The animals were exposed to the microwave field alone before test sessions combining the drugs with microwave radiation. Microwave exposure alone did not affect FI performance. Microwave radiation in combination with either drug did not produce any alterations in the dose-effect functions.

  1. 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...

  2. 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.

  3. 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.

  4. Nonlinear Correction to Absorption Spectrum under Irradiation of Microwave Field in Conventional BCS Superconductors

    NASA Astrophysics Data System (ADS)

    Jujo, Takanobu

    2017-02-01

    We investigate the absorption spectrum of s-wave superconductors under microwave pump field irradiation. The third-order response function is calculated in the dirty limit with the electron-phonon interaction included at finite temperatures. We find that the nonlinear correction to the linear absorption shows peculiar behavior when the pump field frequency is smaller than the superconducting gap. At finite temperatures, a negative nonlinear correction exists, which is caused by thermally excited quasiparticles. The vertex correction by impurity scattering is found to contain a dissipation mechanism by inelastic scattering (interaction between electrons and acoustic phonons) or nonlocality. We need this mechanism to obtain finite absorption in a nonequilibrium stationary state under a monochromatic external field. Although this term originates from the deformation of a one-particle state, there is also a final-state interaction (the amplitude mode). The latter term represents two-photon excitation and is almost independent of temperature.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. Low Level Infrared Irradiance Ocular Effects.

    DTIC Science & Technology

    1978-11-01

    with a fundus camera reticle before each exposure session and between animals exposed on the same day. The beam was visualized on an IR phosphor excited...means of a fundus camera . The exposure and examination apparatus is shown in Figure 2. If a lesion was detected, the power level was decreased, the beam...Documentation of retinal and lenti- cular effects was provided by fundus and slit lamp photography. Opacities were observed on the posterior poles of the rabbit

  10. Progesterone and estradiol plasma levels in neonatally irradiated cycling rats

    SciTech Connect

    Freud, A.; Sod-Moriah, U.A. )

    1990-01-01

    Female rats which were exposed to a single low dose of gamma irradiation (6R or 15R) at the age of 8 days produce smaller litters when mature than untreated controls. The possibility that the impaired fertility resulted from altered ovarian activity as reflected by changes in plasma levels of progesterone or estardiol was investigated. Plasma levels of both steroids were determined throughout the day of proestrus. Progesterone level was also determined in 6R animals on the day of weaning. The maturity of such irradiated rats was assessed by observing the time of vaginal opening. The results indicated that the preovulatory peak of progesterone was delayed in the 6R rats whereas in the 15R group its levels were significantly lower. On the other hand no differences in estradiol plasma levels were noticed between the groups. The higher level of progesterone in the 6R animals was not evident on the day of weaning and was even in both groups, but vaginal opening in the irradiated rats was significantly delayed. The elevated level of progesterone might be responsible, among other endocrine changes, for the lower fertility of neonatally irradiated mature female rats.

  11. 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.

  12. Alkaline solubilization and microwave irradiation as a combined sludge disintegration and minimization method.

    PubMed

    Doğan, Ilgin; Sanin, F Dilek

    2009-05-01

    Commonly used pretreatment method of alkaline solubilization (using NaOH) and a relatively new technology of microwave (MW) irradiation (160 degrees C) were combined as a pretreatment method of waste activated sludge (WAS) in this study. First alkaline and MW pretreatment methods were examined separately, then their combination for different conditions was investigated in terms of their effect on COD solubilization, turbidity and capillary suction time (CST). For combined pretreatments, soluble COD to total COD ratio (SCOD/TCOD) of WAS increased from 0.005 (control) to 0.18, 0.27, 0.34 and 0.37 for combined methods of MW and pH-10, 11, 12 and 12.5, respectively. Deteriorated dewaterability due to alkaline pretreatment was also improved due to the incorporation of MW irradiation. Further, with small scale batch anaerobic reactors, pH-10, pH-12, MW (alone), MW+pH-10 and MW+pH-12 pretreated WAS samples were anaerobically digested. Highest total gas and methane productions were achieved with MW+pH-12 pretreatment with 16.3% and 18.9% improvements over control reactor, respectively. Finally the performance of MW+pH-12 pretreatment was examined with 2L anaerobic semi-continuous reactors for 92 days and compared to that of the control reactors. These reactors were operated at an SRT of 15 days. After steady state, 43.5% and 55% improvements were obtained in respective daily total gas and methane productions. TS, VS and TCOD reductions were improved by 24.9%, 35.4% and 30.3%, respectively based on a relative calculation with respect to control reactors. This way combined alkaline-microwave treatment proved to be an effective sludge minimization method. Pretreated digested sludge had 22% improved dewaterability than unpretreated digested sludge. Higher SCOD and NH(3)-N concentrations were measured in the pretreated digested sludge supernatant; however, PO(4)-P concentration did not increase much.

  13. [Dependence of changes in summary bioelectric activity of the brain on low-intensity microwave irradiation from density of flow energy].

    PubMed

    Luk'ianova, S N; Makarov, V P; Rynskov, V V

    1996-01-01

    In present experimental research has found the confirmation the opinion existing in literature about absence of direct proportional dependence effects of low-intensity microwave from density of flow of energy. Work submits the analysis electroencephalograms various areas of the cortex brain of rabbits on 6 GHz microwave irradiation with energy 0.03-0.40 MW/sm2.

  14. Microbial short-chain fatty acid production and extracellular enzymes activities during in vitro fermentation of polysaccharides from the seeds of Plantago asiatica L. treated with microwave irradiation.

    PubMed

    Hu, Jie-Lun; Nie, Shao-Ping; Li, Chang; Fu, Zhi-Hong; Xie, Ming-Yong

    2013-06-26

    Effects of microwave irradiation on microbial short-chain fatty acid production and the activites of extracellular enzymes during in vitro fermentation of the polysaccharide from Plantago asiatica L. were investigated in this study. It was found that the apparent viscosity, average molecular weight, and particle size of the polysaccharide decreased after microwave irradiation. Reducing sugar amount increased with molecular weight decrease, suggesting the degradation may derive from glycosidic bond rupture. The polysaccharide surface topography was changed from large flakelike structure to smaller chips. FT-IR showed that microwave irradiation did not alter the primary functional groups in the polysaccharide. However, short-chain fatty acid productions of the polysaccharide during in vitro fermentation significantly increased after microwave irradiation. Activities of microbial extracellular enzymes xylanase, arabinofuranosidase, xylosidase, and glucuronidase in fermentation cultures supplemented with microwave irradiation treated polysaccharide were also generally higher than those of untreated polysaccharide. This showed that microwave irradiation could be a promising degradation method for the production of value-added polysaccharides.

  15. 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.

  16. Fabrication of hexagonal ZnO nanorods on porous carbon matrix by microwave irradiation.

    PubMed

    Suresh, P; Vijaya, J Judith; Kennedy, L John

    2013-04-01

    The hexagonal ZnO nanorods supported activated carbon (ZSAC) was successfully prepared using zinc nitrate hexahydrate and urea through microwave irradiation. The method of preparation is simple and cost effective. The activated carbon (AC) with high surface area (446.44 m2/g), pore volume (00.21 cm3/g) and average pore diameter (01.89 nm) was employed as a matrix support for the growth of ZnO nanorods. The XRD results affirm the formation of wurtzite ZnO nanostructures. The FT-IR studies disclose the presence of varied functional groups present in ZSAC. The HR-SEM images reveal the pore morphology of AC and hexagonal shape of ZnO nanorods formed. The E(g) value obtained from Kubelka-Munk transformed reflectance spectra is about 3.43 eV. The photoluminescence emissions reveal the defects in the crystal lattice. The ZSAC thus prepared would perform substantial role in the area of catalysis.

  17. Effects of morphology on photocatalytic performance of Zinc oxide nanostructures synthesized by rapid microwave irradiation methods

    NASA Astrophysics Data System (ADS)

    Kajbafvala, Amir; Ghorbani, Hamed; Paravar, Asieh; Samberg, Joshua P.; Kajbafvala, Ehsan; Sadrnezhaad, S. K.

    2012-04-01

    In this study, two different chemical solution methods were used to synthesize Zinc oxide nanostructures via a simple and fast microwave assisted method. Afterwards, the photocatalytic performances of the produced ZnO powders were investigated using methylene blue (MB) photodegradation with UV lamp irradiation. The obtained ZnO nanostructures showed spherical and flower-like morphologies. The average crystallite size of the flower-like and spherical nanostructures were determined to be about 55 nm and 28 nm, respectively. X-ray diffraction (XRD), scanning electronic microscopy (SEM), Brunauer-Emmett-Teller (BET), room temperature photoluminescence (RT-PL) and UV-vis analysis were used for characterization of the synthesized ZnO powders. Using BET N2-adsorption technique, the specific surface area of the flower-like and spherical ZnO nanostructures were found to be 22.9 m2/gr and 98 m2/gr, respectively. Both morphologies show similar band gap values. Finally, our results depict that the efficiency of photocatalytic performance in the Zinc oxide nanostructures with spherical morphology is greater than that found in the flower-like Zinc oxide nanostructures as well as bulk ZnO.

  18. 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.

  19. Extractive-transesterification of algal lipids under microwave irradiation with hexane as solvent.

    PubMed

    Martinez-Guerra, Edith; Gude, Veera Gnaneswar; Mondala, Andro; Holmes, William; Hernandez, Rafael

    2014-03-01

    This study describes the use of microwaves (MW) for enhanced extractive-transesterification of algal lipids from dry algal biomass (Chlorella sp.). Two different single-step extractive-transesterification methods under MW irradiation were evaluated: (1) with ethanol as solvent/reactant and sodium hydroxide catalyst; and (2) with ethanol as reactant and hexane as solvent (sodium hydroxide catalyst). Biodiesel (fatty-acid-ethyl-esters, FAEE) yields from these two methods were compared with the conventional Bligh and Dyer (BD) method which followed a two-step extraction-transesterification process. The maximum lipid yields for MW, MW with hexane and BD methods were 20.1%, 20.1%, and 13.9%, respectively; while the FAEE conversion of the algal lipids were 96.2%, 94.3%, and 78.1%, respectively. The algae-biomass:ethanol molar ratio of 1:250-500 and 2.0-2.5% catalyst with reaction times around 6min were determined as optimum conditions for both methods. This study confers that the single-step non-conventional methods can contribute to higher algal lipid and FAEE yields.

  20. 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.

  1. [Modification of the effects of microwave irradiation on biochemical processes by using foreign protein].

    PubMed

    Podkovkin, V G; Uglova, I B

    1998-01-01

    The biochemical data on the influence of electromagnetic fields in microwave range on the hormonal-mediator regulation systems are presented. The possibility of biological effects modification under combined action of microwave radiation and foreign protein is discussed.

  2. Environmentally friendly chemical recycling of poly(bisphenol-A carbonate) through phase transfer-catalysed alkaline hydrolysis under microwave irradiation.

    PubMed

    Tsintzou, Georgia P; Antonakou, Eleni V; Achilias, Dimitris S

    2012-11-30

    The various and widespread uses of polycarbonate (PC) polymers require a meaningful and environmentally friendly disposal method. In this study, depolymerisation of polycarbonate with water in a microwave reactor is suggested as a recycling method. Hydrolysis was investigated in an alkaline (NaOH) solution using a phase-transfer catalyst. All of the experiments were carried out in a sealed microwave reactor, in which the reaction pressure, temperature and microwave power were continuously controlled and recorded. In the hydrolysis products, bisphenol-A monomer was obtained and identified by FTIR measurements. PC degradation higher than 80% can be obtained at 160°C after a microwave irradiation time of either 40 min or 10 min using either a 5 or 10% (w/v) NaOH solution, respectively. GPC, TGA and DSC measurements of the PC residues revealed that surface erosion is the degradation mechanism. First-order reaction kinetics were estimated by implementing a simple kinetic model. Finally, greater than 85% degradation was achieved when waste CDs were treated with the same method. The results confirm the importance of the microwave power technique as a promising recycling method for PC-based waste plastics, resulting in monomer recovery in addition to substantial energy savings.

  3. Fast solid state synthesis of metal vanadates and chalcogenides using microwave irradiation

    SciTech Connect

    Vaidhyanathan, B.; Ganguli, M.; Rao, K.J.

    1995-09-01

    Metal vanadates and chalcogenides have been prepared in rapid time scales using a domestic microwave oven. The products exhibit high phase purity and homogeneity. The thermal and spectroscopic properties of the microwave prepared metal vanadates match well with those prepared by conventional methods. The most important advantages in microwave assisted synthesis appear to be the very short time scales required for the preparation and the selectivity in energy transfer from microwave field.

  4. 2.45-GHz microwave irradiation adversely affects reproductive function in male mouse, Mus musculus by inducing oxidative and nitrosative stress.

    PubMed

    Shahin, S; Mishra, V; Singh, S P; Chaturvedi, C M

    2014-05-01

    Electromagnetic radiations are reported to produce long-term and short-term biological effects, which are of great concern to human health due to increasing use of devices emitting EMR especially microwave (MW) radiation in our daily life. In view of the unavoidable use of MW emitting devices (microwaves oven, mobile phones, Wi-Fi, etc.) and their harmful effects on biological system, it was thought worthwhile to investigate the long-term effects of low-level MW irradiation on the reproductive function of male Swiss strain mice and its mechanism of action. Twelve-week-old mice were exposed to non-thermal low-level 2.45-GHz MW radiation (CW for 2 h/day for 30 days, power density = 0.029812 mW/cm(2) and SAR = 0.018 W/Kg). Sperm count and sperm viability test were done as well as vital organs were processed to study different stress parameters. Plasma was used for testosterone and testis for 3β HSD assay. Immunohistochemistry of 3β HSD and nitric oxide synthase (i-NOS) was also performed in testis. We observed that MW irradiation induced a significant decrease in sperm count and sperm viability along with the decrease in seminiferous tubule diameter and degeneration of seminiferous tubules. Reduction in testicular 3β HSD activity and plasma testosterone levels was also noted in the exposed group of mice. Increased expression of testicular i-NOS was observed in the MW-irradiated group of mice. Further, these adverse reproductive effects suggest that chronic exposure to nonionizing MW radiation may lead to infertility via free radical species-mediated pathway.

  5. Microwave irradiation on carbon black: Studies on the transformation of particles into nano-balls, nano-sticks and nano-onion like structures

    NASA Astrophysics Data System (ADS)

    Asokan, Vijayshankar; Venkatachalapathy, Vishnukanthan; Rajavel, Krishnamoorthy; Madsen, Dorte Nørgaard

    2016-12-01

    The solid-state transformation behavior of carbon black (CB) nanoparticles after irradiated with microwave energy was studied with and without influence of a metal catalyst. The CB sample was exposed to microwave radiation at power of 900 W from the oven and collected after 15 min and after 30 min and 45 min of irradiation. The samples were characterized using X-ray diffraction measurements, Raman spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy (HRTEM) and thermogravimetric analysis. Characterization of the samples prepared without catalyst shows that microwave irradiation can transform CB nanoparticles into nano-balls and nano-stick like structures. While nanoballs of almost 300-500 nm diameter are visible in all the samples irrespective of microwave irradiation time, amorphous nano-stick like structure are present only in the sample collected after 30 min of microwave irradiation. CB irradiated together with a metal catalyst resulted in metal-encapsulated onion like structures with perfectly arranged graphene layers.

  6. Microwave irradiation: synthesis and characterization of α-ketoamide and bis (α-ketoamide) derivatives via the ring opening of N-acetylisatin

    PubMed Central

    2014-01-01

    Background The carbonyl group at position 2 of N-acetylisatin behaves as an amide which is more susceptible to nucleophilic attack via ring-opening in the presence of nucleophiles. Because of this behavior, in the present work we describe the microwave synthesis of a series of α-ketoamide and bis-(α-ketoamide) derivatives via the facile ring-opening of N-acylisatin with different amines and diamines. The microwave irradiation afforded the product in less reaction time, higher yield and purity. Reaction of N-acylisatin with methanol under microwave irradiation afforded the α-phenylglyoxyl methyl ester derivatives with excellent yields and purities. Aminolysis of the ester derivatives with piperidine and morpholine afforded the same α-ketoamide derivatives obtained from direct aminolysis of N-acylisatin. The structures of the synthesized compounds were confirmed by FT-IR, NMR, X-ray and elemental analysis. Results Reaction of N-acetylisatin and N-propoionylsatin with different amines and diamines afforded a series of α-ketoamide and bis-(α-ketoamide) derivatives respectively via the ring opening of N-acylisatins. The reaction was performed under conventional condition as well as microwave irradiation. The microwave irradiation afforded the product in less reaction time, higher yield and purity. Reaction of N-acylisatin with methanol under microwave irradiation afforded the α-phenylglyoxyl methyl ester derivatives in excellent yields and purities as observed from their spectral data. A plausible mechanism involves nucleophilic attack by methanol at C2 carbonyl carbon of N-acetylisatin and subsequent ring opening to generate the α-ketoester. Aminolysis of α-ketoester with amine afforded the same α-ketoamide which is obtained by direct aminolysis of N-acylisatin. The IR, NMR spectra, microanalyses, and single crystal X-ray diffraction confirmed the structures of the synthesized compounds. Conclusions In conclusion, we have demonstrated that microwave

  7. Changes in human EEG caused by low level modulated microwave stimulation.

    PubMed

    Hinrikus, Hiie; Parts, Maie; Lass, Jaanus; Tuulik, Viiu

    2004-09-01

    This study focuses on the effect of low level microwave radiation on human EEG alpha and theta rhythms. During the experiment, 20 healthy volunteers were exposed to a 450 MHz microwaves with 7 Hz on-off modulation. The field power density at the scalp was 0.16 mW/cm2. Signals from the following EEG channels were used: FP1, FP2, P3, P4, T3, T4, O1, and O2. The experimental protocol consisted of one cycle of short term photic and ten cycles of the repetitive microwave stimulation. The changes caused by photic as well as microwave stimulation were more regular on the alpha rhythm. In the majority of cases, photic stimulation caused changes in the EEG energy level in the occipital and microwave stimulation in the frontal region. Our experimental results demonstrated that microwave stimulation effects became apparent, starting from the third stimulation cycle. Changes varied strongly from subject to subject. Therefore, photic and microwave exposure did not cause statistically significant changes in the EEG activity level for the whole group. For some subjects, clear tendencies of changes in microwave on-off cycles were noticeable.

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

    PubMed

    Qvit, Nir; Kornfeld, Opher S

    2016-01-26

    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

  9. Microwave synthesis of zeolites. 2. Effect of vessel size, precursor volume, and irradiation method.

    PubMed

    Panzarella, Bernard; Tompsett, Geoffrey A; Yngvesson, K Sigfrid; Conner, W Curtis

    2007-11-08

    The enhancement of synthesis reactions under microwave heating is dependent on many complex factors. We investigated the importance of several reaction engineering parameters relevant to microwave synthesis. Of interest to this investigation were the reaction vessel size, volume of precursor reacted, microwave power delivery, and microwave cavity design. The syntheses of NaY zeolite and beta-zeolite were carried out under a number of varying conditions to determine the influence of these parameters on the nucleation rate, the crystallization rate, and the particle size and morphology. The rates of NaY and beta-zeolite nucleation and crystallization were more rapid in the multimode CEM MARS-5 oven compared to the more uniform field CEM Discover. The faster synthesis rate in the MARS-5 may be the result of the multimode microwave electric field distribution. Slower rates of NaY and beta-zeolite formation observed in the Discover and a circular waveguide may be the result of a more uniform microwave electric field distribution. Changes in reaction vessel size and precursor volume during the microwave synthesis of beta- and NaY zeolite were found to influence the rate of zeolite formation. These results indicate that reactor geometry needs to be considered in the design of systems used for microwave synthesis. Comparative synthesis reactions were carried out with conventional heating, and microwave heating was shown to be up to over an order of magnitude faster for most of these syntheses.

  10. 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.

  11. Physiological changes in rats after exposure to low levels of microwaves

    SciTech Connect

    Ray, S.; Behari, J. )

    1990-08-01

    The effects of exposure to sublethal levels of microwaves were studied. Young albino rats of both sexes were exposed for 60 days to 7.5-GHz microwaves (1.0-KHz square wave modulation, average power 0.6 mW/cm2) for 3 h daily. During and after microwave exposure several physiological parameters were measured in both control and exposed animals. It was found that the animals exposed to microwaves tended to eat and drink less and thus showed a smaller gain in body weight. Some of the hematological parameters and organ weights were also significantly different. It is proposed that a nonspecific stress response due to microwave exposure and mediated through the central nervous system is responsible for the observed physiological changes.

  12. Surfactant-free synthesis of metallic bismuth spheres by microwave-assisted solvothermal approach as a function of the power level

    NASA Astrophysics Data System (ADS)

    Estrada Flores, Miriam; Santiago Jacinto, Patricia; Reza San Germán, Carmen M.; Rendón Vázquez, Luis; Borja Urby, Raúl; Cayetano Castro, Nicolás

    2016-10-01

    In the present work, the synthesis of micro- and nano-sized spheres of metallic bismuth by microwave-assisted solvothermal method is reported. The synthesis method was carried out at different power levels and at a unique frequency of microwave irradiation. The sphere sizes were controlled by the microwave power level and the concentration of dissolved precursor. Structural and morphological characterization was performed by SEM, HRTEM, EELS and XRD. The results demonstrated that rhombohedral zero valent Bi spheres were synthesized after microwave radiation at 600 and 1200 W. However, if the power level is decreased to 120W, a monoclinic phase of Bi2O3 is obtained with a flake-like morphology. In comparison with a conventional hydrothermal process, the microwave-assisted solvothermal approach provides many advantages such as shorter reaction time, optimum manipulation of morphologies and provides a specific chemical phase and avoids the mixture of structural phases and morphologies which is essential for further applications such as drug delivery or functionalization with organic materials, thanks to its biocompatibility.

  13. Electromagnetically induced transparency in the four-level system driven by bichromatic microwave field

    NASA Astrophysics Data System (ADS)

    Yang, Lijun; Sun, Ke-jia; Zhang, Su-heng; Feng, Xiao-min

    2014-11-01

    We present a theoretical study on the nonlinear behaviors of the electromagnetically induced transparency resonance subject to two microwave driving fields in a four-level atom system. The probe absorption spectrum is obtained by solving numerically the relevant equations of density matrix. It is shown that there are two pairs of the EIT windows in the probe absorption spectrum. The two pairs of EIT windows have symmetry with respect to the resonance frequency of the probe field, and the separation is equal to the Rabi frequency of the resonant microwave driving field. But in each pair, the splitting of two EIT windows is dominated to the strength of detuning microwave driving field.

  14. Mechanism of low-level microwave radiation effect on nervous system.

    PubMed

    Hinrikus, Hiie; Bachmann, Maie; Karai, Denis; Lass, Jaanus

    2017-01-01

    The aim of this study is to explain the mechanism of the effect of low-level modulated microwave radiation on brain bioelectrical oscillations. The proposed model of excitation by low-level microwave radiation bases on the influence of water polarization on hydrogen bonding forces between water molecules, caused by this the enhancement of diffusion and consequences on neurotransmitters transit time and neuron resting potential. Modulated microwave radiation causes periodic alteration of the neurophysiologic parameters and parametric excitation of brain bioelectric oscillations. The experiments to detect logical outcome of the mechanism on physiological level were carried out on 15 human volunteers. The 450-MHz microwave radiation modulated at 7, 40 and 1000 Hz frequencies was applied at the field power density of 0.16 mW/cm(2). A relative change in the EEG power with and without radiation during 10 cycles was used as a quantitative measure. Experimental data demonstrated that modulated at 40 Hz microwave radiation enhanced EEG power in EEG alpha and beta frequency bands. No significant alterations were detected at 7 and 1000 Hz modulation frequencies. These results are in good agreement with the theory of parametric excitation of the brain bioelectric oscillations caused by the periodic alteration of neurophysiologic parameters and support the proposed mechanism. The proposed theoretical framework has been shown to predict the results of experimental study. The suggested mechanism, free of the restrictions related to field strength or time constant, is the first one providing explanation of low-level microwave radiation effects.

  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. Microwave irradiation induced modifications on the interfaces in SAN/EVA/PVC and PVAc/BPA/PVP ternary polymer blends: Positron lifetime study

    NASA Astrophysics Data System (ADS)

    Dinesh, Meghala; Chikkakuntappa, Ranganathaiah

    2013-09-01

    Ternary polymer blends of poly(styrene-co-acrylonitrile)/poly(ethylene-co-vinylacetate)/poly(vinyl chloride) (SAN/EVA/PVC) and poly(vinyl acetate)/bisphenol A/polyvinylpyrrolidone (PVAc/BPA/PVP) with different compositions have been prepared by solvent casting method and characterized by positron lifetime spectroscopy and differential scanning calorimetry DSC. Phase modifications have been induced by irradiating the blends with microwave radiation. These changes have been monitored by measuring the free-volume content in the blends. The results clearly show improved interactions between the constituent polymers of the blends upon microwave irradiation. However, the free-volume data and DSC measurements are found to be inadequate to reveal the changes at the interfaces and the interfaces determine the final properties of the blend. For this we have used hydrodynamic interaction (αij) approach developed by us to measure strength of hydrodynamic interaction at the interfaces. These results show that microwave irradiation stabilizes the interfaces if the blend contains strong polar groups. SAN/EVA/PVC blend shows an increased effective hydrodynamic interaction from -3.18 to -4.85 at composition 50/35/15 upon microwave irradiation and PVAc/BPA/PVP blend shows an increased effective hydrodynamic interaction from -3.81 to -7.57 at composition 20/50/30 after irradiation.

  17. 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.

  18. Non-linear transport in microwave-irradiated 2D electron systems at the cyclotron resonance subharmonics

    NASA Astrophysics Data System (ADS)

    Chiang, Hung-Sheng; Hatke, Anthony; Zudov, Michael; Pfeiffer, Loren; West, Ken

    2009-03-01

    We study microwave photoresistivity oscillations in a high mobility two-dimensional electron system subject to strong dc electric fields. We find [1] that near the second subharmonic of the cyclotron resonance the frequency of the resistivity oscillations with dc electric field is twice the frequency of the oscillations at the cyclotron resonance, its harmonics, or in the absence of microwave radiation. This observation is discussed in terms of the microwave-induced sidebands in the density of states and the interplay between different scattering processes in the separated Landau level regime. [1] A. T. Hatke, H.-S. Chiang, M. A. Zudov, L. N. Pfeiffer, and K. W. West, Phys. Rev. Lett. accepted for publication.

  19. 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.

  20. Microwave absorption by magnetite: a possible mechanism for coupling nonthermal levels of radiation to biological systems.

    PubMed

    Kirschvink, J L

    1996-01-01

    The presence of trace amounts of biogenic magnetite (Fe3O4) in animal and human tissues and the observation that ferromagnetic particles are ubiquitous in laboratory materials (including tissue culture media) provide a physical mechanism through which microwave radiation might produce or appear to produce biological effects. Magnetite is an excellent absorber of microwave radiation at frequencies between 0.5 and 10.0 GHz through the process of ferromagnetic resonance, where the magnetic vector of the incident field causes precession of Bohr magnetons around the internal demagnetizing field of the crystal. Energy absorbed by this process is first transduced into acoustic vibrations at the microwave carrier frequency within the crystal lattice via the magnetoacoustic effect; then, the energy should be dissipated in cellular structures in close proximity to the magnetite crystals. Several possible methods for testing this hypothesis experimentally are discussed. Studies of microwave dosimetry at the cellular level should consider effects of biogenic magnetite.

  1. Comparison of the effects of microwave irradiation with different intensities on the biodegradability of sludge from the dairy- and meat-industry.

    PubMed

    Beszédes, Sándor; László, Zsuzsanna; Horváth, Zsuzsanna H; Szabó, Gábor; Hodúr, Cecilia

    2011-01-01

    Microwave (MW) irradiation is a relatively new possibility of conditioning and pretreating for wastewater sludge. Following its application in the telecommunications and food-industries, the environmental use of this technique has come into the limelight in recent years, and has become increasingly popular. Various publications have dealt with the examination of the effects of MW irradiation in municipal sludge-handling processes. We focused on the effects of MW irradiation at different power levels on solubilization (sCOD/tCOD), biodegradation and anaerobic digestion of sludge from the food-industry. For evaluating the efficiency of MW pre-treatment, the changes in the soluble fraction of the organic matter, the VS/TS ratio, the biogas yield, the methane content in the biogas, and the rate of batch mesophilic digestion were used as control parameters. Additionally, the energetic efficiency of MW pre-treatment was also examined. The results were compared with those of conventional heat (CH) treatments of the same sludge. The MW treatment proved to increase both the sCOD/tCOD and the VS/TS ratio. Furthermore, the biogas and methane yields increased during the digestion of the MW-pretreated food-industry sludge. A higher MW power level generally enhanced the biogas and methane production. Energetically, the most economic pre-treatment of sludge from dairy and meat processing was at a power level of 1.5 Wg(-1) and 2.5 Wg(-1) MW respectively; the surplus energy content of the enhanced biogas product could not compensate the extra energy demand of the stronger MW pre-treatments.

  2. Measurement of evaporation rates of different kind of aqueous solutions under microwave irradiation.

    PubMed

    Unak, Turan; Ekim, Selen; Sarican, Gözde; Cetin, Cigdem; Unak, Gülcan

    2012-01-01

    The evaporation rate of water is, of course, different under the same heating conditions of different aqueous solutions. Under conventional heating conditions, the evaporation rate of water is much higher than the evaporation rate of water of aqueous solutions of different kinds of solute materials, which is well accordance with the classical Raoult's law. The results obtained in this study have clearly shown that the chemical characteristics of dissolved materials in water very seriously affect the evaporation rates of water under the microwave heating. This generally causes contradictory results to Raoult's law and this can be explained with the additional microwave energy absorption by the ionic or molecular solute materials found in the solutions other than the microwave energy absorption by water molecules themselves.

  3. 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...

  4. 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)].

  5. 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.

  6. 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...

  7. 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...

  8. Effects of microwave (2.45 GHz) irradiation on some biological characters of Salmonella typhimurium.

    PubMed

    Nasri, Kaouther; Daghfous, Douraid; Landoulsi, Ahmed

    2013-04-01

    The present study was carried out to evaluate the effects of sub-lethal doses of microwave radiation on some biological characteristics in Salmonella typhimurium. The aim was to show the relationship between this treatment and the development of radiotolerance in this pathogen because there is a need for more information on physiological responses of pathogens to sub-lethal doses of microwave radiation. So, the bacterial strain was treated with a dose of 3600J (40-s exposure with power P=90 W) to cause cellular damage. The results have shown that the exposure of bacteria to microwaves resulted in a significant inhibition of cellular growth. This treatment has notably increased the effectiveness of the most tested antibiotics by the amelioration or the appearance of sensitivity in exposed bacteria. Gas chromatography (GC) analysis was performed to demonstrate the modification of the fatty acids (FA) composition. Results obtained have shown that this treatment had a significant effect on the FA content with an increase of unsaturated FA percentage. The acquisition of sensitivity to the sodium deoxycholate and the significant increase in the amount of extracellular proteins in exposed bacteria has confirmed the weakening of the bacterial membrane by microwaves. This study represents one of the few demonstrating the modifications on the bacterial membrane as a cellular response to survive the non-ionising radiation stress.

  9. ‘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...

  10. 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.

  11. 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...

  12. 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...

  13. 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 ...

  14. 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.

  15. Synthesis and characterization of the in situ bulk polymerization of PMMA containing graphene sheets using microwave irradiation.

    PubMed

    Aldosari, Mohammad A; Othman, Ali A; Alsharaeh, Edreese H

    2013-03-11

    Polymethylmethacrylate-graphene (PMMA/RGO) nanocomposites were prepared via in situ bulk polymerization using two different preparation techniques. In the first approach, a mixture of graphite oxide (GO) and methylmethacrylate monomers (MMA) were polymerized using a bulk polymerization method with a free radical initiator. After the addition of the reducing agent hydrazine hydrate (HH), the product was reduced via microwave irradiation (MWI) to obtain R-(GO-PMMA) composites. In the second approach, a mixture of graphite sheets (RGO) and MMA monomers were polymerized using a bulk polymerization method with a free radical initiator to obtain RGO-(PMMA) composites. The composites were characterized by FTIR, (1)H-NMR and Raman spectroscopy and XRD, SEM, TEM, TGA and DSC. The results indicate that the composite obtained using the first approach, which involved MWI, had a better morphology and dispersion with enhanced thermal stability compared with the composites prepared without MWI.

  16. The novel and economical way to synthesize CuS nanomaterial of different morphologies by aqueous medium employing microwaves irradiation

    NASA Astrophysics Data System (ADS)

    Nafees, Muhammad; Ali, Salamat; Rasheed, Khalid; Idrees, Saima

    2012-06-01

    CuS nano/submicro materials with different morphologies were synthesized with spherical, tubular, leaf-like and strip type structures in a simple aqueous system under microwave irradiation and sunlight and employing Cu (CH3COO)2, CuSO4·5H2O, CuCl2, and as copper source and H2NCSNH2, Na2S2O3·5H2O and CH3CSNH2 as sulfur sources. The starting materials were used without assistance of any surfactant or template. An X-ray powder diffraction pattern confirms that the product was CuS with hexagonal phase. Scanning electron microscopy was used to observe the morphologies of the product. Different Phase transitions in CuS with respect to temperature are studied by DSC/TGA. The dependence of morphologies of product on different experimental conditions was also discussed.

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

    PubMed

    Sampieri, Alvaro; Lima, Enrique

    2009-04-09

    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.

  18. 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.

  19. 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.

  20. 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.

  1. Chelant-induced reclamation of indium from the spent liquid crystal display panels with the aid of microwave irradiation.

    PubMed

    Hasegawa, Hiroshi; Rahman, Ismail M M; Egawa, Yuji; Sawai, Hikaru; Begum, Zinnat A; Maki, Teruya; Mizutani, Satoshi

    2013-06-15

    Indium is a rare metal that is mostly consumed as indium tin oxide (ITO) in the fabrication process of liquid crystal display (LCD) panels. The spent LCD panels, termed as LCD-waste hereafter, is an increasing contributor of electronic waste burden worldwide and can be an impending secondary source of indium. The present work reports a new technique for the reclamation of indium from the unground LCD-waste using aminopolycarboxylate chelants (APCs) as the solvent in a hyperbaric environment and at a high-temperature. Microwave irradiation was used to create the desired system conditions, and a substantial abstraction of indium (≥80%) from the LCD-waste with the APCs (EDTA or NTA) was attained in the acidic pH region (up to pH 5) at the temperature of ≥120 °C and the pressure of ~50 bar. The unique point of the reported process is the almost quantitative recovery of indium from the LCD-waste that ensured via the combination of the reaction facilitatory effect of microwave exposure and the metal extraction capability of APCs. A method for the selective isolation of indium from the extractant solution and recycle of the chelant in solution is also described.

  2. Effects of cytoplasm and reactant polarities on acid-catalyzed lipid transesterification in wet microalgal cells subjected to microwave irradiation.

    PubMed

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

    2016-01-01

    The polarities of the cytoplasm and reactants were measured through dielectric spectroscopy, contact angle test, NMR, and FTIR to investigate the mechanisms underlying acid-catalyzed lipid transesterification in wet microalgal cells subjected to microwave irradiation. Organics with apolar functional groups in the cytoplasm decreased the contact angle of methanol against triglyceride by 13.92°, which subsequently increased transesterification efficiency by 2.4 times. The microalgal biomass, given its higher hydrophilicity index of 1.96 than lipids, was more accessible to hydrophilic alcohols, which subsequently promoted transesterification. Water in the cytoplasm promoted the dielectric constant of methanol and increased the contact angle of methanol against triglyceride by 20.51°, which subsequently decreased transesterification efficiency by 72.6%. The inhibitory effect of water on transesterification weakened with the prolonged carbon lengths of the alcohols because of decreased polarity. Microwave decreased the electric constants of alcohols and reduced the polarity difference between alcohols and lipids, thereby improving transesterification efficiency.

  3. 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.

  4. 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.

  5. 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 C-C reactions under microwave irradiation using a solvent-free reaction condition. The catalytic tests showed an excellent activity with a small load of the catalyst (0.02 mol%) in 4 min. 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.

  6. 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.

  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. 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.

  9. 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.

  10. 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.

  11. Thawing of foods in a microwave oven: I. Effect of power levels and power cycling.

    PubMed

    Chamchong, M; Datta, A K

    1999-01-01

    Microwave thawing is faster than other methods, but it can produce significant non-uniformity of heating. The objective of this study was to perform comprehensive experimentation and heat transfer modeling to relate the time to thaw and the non-uniformity of thawing to power cycling, power level and the surface heat transfer coefficient. The governing energy equation was formulated with an exponential decay of the microwave flux from the surface. Surface microwave flux was obtained from the measured temperature rise using inverse heat transfer analysis. Gradual phase change was formulated as an apparent specific heat, and was obtained for the experimental material tylose from differential scanning calorimetry (DSC) measurements. The temperatures were measured immediately following heating with a fast response thermocouple. Dielectric properties were measured above freezing. Results show that the microwave flux at the surface and its decay are affected by the changes in the power level. Power cycling has an almost identical effect as continuous power at the reduced level of the average cycled power. As power level increases, the surface flux increases by the same fraction. At higher power levels, however, the outside thaws relatively faster. A "shield" develops due to a much reduced microwave penetration depth at the surface. This thawing time at higher power levels is reduced considerably. Temperature increases initially are non-uniform since the surface is heated at a faster rate than the interior. In keeping with the assumption that once the temperature reaches 100 degrees C, all energy absorbed goes into evaporation, and subsequent temperature is maintained at 100 degrees C. Thus, eventually, non-uniformity starts to decrease.

  12. 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.

  13. Effects of irradiation source and dose level on quality characteristics of processed meat products

    NASA Astrophysics Data System (ADS)

    Ham, Youn-Kyung; Kim, Hyun-Wook; Hwang, Ko-Eun; Song, Dong-Heon; Kim, Yong-Jae; Choi, Yun-Sang; Song, Beom-Seok; Park, Jong-Heum; Kim, Cheon-Jei

    2017-01-01

    The effect of irradiation source (gamma-ray, electron-beam, and X-ray) and dose levels on the physicochemical, organoleptic and microbial properties of cooked beef patties and pork sausages was studied, during 10 days of storage at 30±1 °C. The processed meat products were irradiated at 0, 2.5, 5, 7.5, and 10 kGy by three different irradiation sources. The pH of cooked beef patties and pork sausages was unaffected by irradiation sources or their doses. The redness of beef patties linearly decreased with increasing dose level (P<0.05), obviously by e-beam irradiation compared to gamma-ray and X-ray (P<0.05). The redness of pork sausages was increased by gamma-ray irradiation, whereas it decreased by e-beam irradiation depending on absorbed dose level. No significant changes in overall acceptability were observed for pork sausages regardless of irradiation source (P>0.05), while gamma-ray irradiated beef patties showed significantly decreased overall acceptability in a dose-dependent manner (P<0.05). Lipid oxidation of samples was accelerated by irradiation depending on irradiation sources and dose levels during storage at 30 °C. E-beam reduced total aerobic bacteria of beef patties more effectively, while gamma-ray considerably decreased microbes in pork sausages as irradiation dose increased. The results of this study indicate that quality attributes of meat products, in particular color, lipid oxidation, and microbial properties are significantly influenced by the irradiation sources.

  14. 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.

  15. Preserving effects of melatonin on the levels of glutathione and malondialdehyde in rats exposed to irradiation.

    PubMed

    Yildirim, O; Comoğlu, S; Yardimci, S; Akmansu, M; Bozkurt, G; Sürücü, S

    2008-03-01

    In this study we investigated whether pretreatment with melatonin was protective against the injury of the central nervous system (CNS) in rats receiving LD(50) whole body irradiation. The wistar rats were randomized into four groups: i) the control group (CG), ii) melatonin-administered group (MG; 1 mg/kg body weight), iii) irradiated group (RG; 6.75 Gy, one dose), and iv) melatonin-administered and irradiated group (MRG). Blood samples were drawn from the rats 24 h after the treatment and plasma glutathione levels were assayed. Plasma glutathione level was significantly higher in RG than CG. The melatonin pretreatment prevented GSH increase induced by irradiation. Lipid peroxidation and glutathione levels of rat cerebral cortex were determined in all groups after 24 h. Cortical malondialdehyde (MDA) was significantly higher in the RG. The melatonin pretreatment prevented cortical MDA increase induced by irradiation. Cortical GSH was significantly lower in RG than the CG. The melatonin pretreatment prevented cortical GSH decrease induced by irradiation. Tissue samples were obtained from cerebral cortex and hypothalamus which also were affected by ionizing irradiation in the CNS and were evaluated with electron microscopy. Histopathological findings showed that LD(50) whole body irradiation resulted in damage of the neuronal cells of CNS. The results obtained from this study demonstrated that pretreatment with melatonin prevented the damage that develops in CNS following irradiation. The beneficial effect of melatonin can be related to protection of the CNS from oxidative injury and preventing the decrease in the level of cortical glutathione.

  16. The Influence of Chronic Exposure to Low Level Pulsed Microwave Radiation on Performance and Cognitive Behavior.

    DTIC Science & Technology

    1983-05-15

    response having defint .’e survival value for the animal (reinforced, low rate bar pressing) was markedly retarded, in comparison both with the...Foremost would be the need to handle a large number of animals in virtually identical fashion so that statistically adequate control and experimental...rat be irradiated independently, that is free of interaction with its neighbors, that the irradiation levels be stable for all animals in a group and

  17. 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

  18. 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.

  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).

  20. High-peak-irradiance microwave-powered UV lamps for processing of coatings, inks, and adhesives

    NASA Astrophysics Data System (ADS)

    Stowe, Richard W.

    1993-01-01

    The number and variety of applications for UV curable inks, coatings, and adhesives continue to expand at a rapid pace, and pose new design challenges to increase cure efficiency, speed, and the physical properties of the cured polymer film. The latest developments in microwave powered lamps for industrial processing are presented. Among these are: (1) the selection and control of the lamp emission spectra to match the optical properties of the film and its photoinitiator, (2) sustained high power lamp operation at 6 kilowatts, and (3) the use of absorptive dichroic reflectors to mange the relative components of UV and infrared energy in the highly focused radiation delivered to surfaces being processed. The design considerations of high powered UV lamps and dichroic reflectors for them are presented.

  1. Efficient degassing of dissolved oxygen in aqueous media by microwave irradiation and the effect of microwaves on a reaction catalyzed by Wilkinson's catalyst

    NASA Astrophysics Data System (ADS)

    Horikoshi, Satoshi; Matsuzaki, Shohei; Sakamoto, Shintaro; Serpone, Nick

    2014-04-01

    To the extent that some reactions are oxygen-sensitive, we herein examined the degassing of dissolved oxygen in water and in 2-propanol solvent by microwave heating with regard to the effects of the microwave frequency (2.45 GHz versus 915 MHz), and with regard to when samples are subjected to electric-field-rich and magnetic-field rich 2.45-GHz microwaves. Changes in the quantity of dissolved oxygen were ascertained by monitoring its concentration in such solvents when exposed to microwave and conventional heating using a polarographic technique and by the chemical oxygen demand (COD) method. The specific microwave (non-thermal) effect played a role in the degassing process on comparing results between microwave heating and conventional heating under identical temperature conditions. The 915-MHz microwaves were more effective, at least at 60 °C, owing to their greater penetration into the solutions. No significant differences were found when degassing was carried out on exposing the water sample to 2.45-GHz microwaves with the sample located within the waveguide at positions rich in either the electric field or the magnetic field (T=80 °C). Conversion of cyclohexanone to cyclohexanol via hydrogen transfer in the presence of Wilkinson's catalyst and 2-propanol solvent (hydrogen source) was also investigated to assess the effect(s) that microwaves might have on this oxygen-sensitive reaction with respect to product yields in contrast to conventional heating by the oil-bath method.

  2. Regio- and stereoselective synthesis of a library of bioactive dispiro-oxindolo/acenaphthoquino andrographolides via 1,3-dipolar cycloaddition reaction under microwave irradiation.

    PubMed

    Hazra, Abhijit; Bharitkar, Yogesh P; Chakraborty, Debanjana; Mondal, Susanta Kumar; Singal, Nupur; Mondal, Shyamal; Maity, Arindam; Paira, Rupankar; Banerjee, Sukdeb; Mondal, Nirup B

    2013-01-14

    Dispiro-pyrrolidino/pyrrolizidino fused oxindoles/acenaphthoquinones have been derived from andrographolide via azomethine ylide cycloaddition to the conjugated double-bond under microwave (MW) irradiation. The reactions are chemo-, stereo-, and regioselective in nature. Change in amino acid from sarcosine/N-benzyl glycine to l-proline changes the regiochemistry. A representative library of 40 compounds along with in vitro anticancer evaluation is reported.

  3. [Thermocompensatory reactions of rabbits in response to microwave irradiation at different environmental temperatures].

    PubMed

    Kolganova, O I; Zhavronkov, L P; Petin, V G; Drozd, A I; Glushakova, V S; Panferova, T A

    2001-01-01

    Thermogenic effectiveness of electromagnetic irradiation (EMI) of UHF range (7 GHz) in the dependence on intensity (10-100 mW/cm2) and environmental temperature was studied in experiments with rabbits. Synergistic interaction of EMI and high ambient temperature was established. The existence of optimal EMI and high ambient temperature was established. The existence of optimal EMI intensity at which the synergy was maximal was shown. It is concluded that this interaction should be taken into account for hygienic standardization of nonionizing EMI.

  4. 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.

  5. 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.

  6. [Low level laser irradiation in the visible spectra induces HeLa cells proliferation].

    PubMed

    Yang, Hong-qin; Wang, Yu-hua; Chen, Jiang-xu; Zheng, Li-qin; Xie, Shu-sen

    2012-04-01

    The aim of this in vitro study was to evaluate the effects of low level laser irradiation on the proliferation of HeLa cells using 405 nm diode laser, 514 nm argon laser, 633 nm He-Ne laser, or 785 nm diode laser, The cells were seeded on 96-well microplates for 24 h in 5% fetal bovine serum containing medium, then irradiated with the laser at dose of 100 and 1 000 J x m(-2), respectively. At the time point of 24, 48, 72 h after irradiation, cell viability was assessed by MTT assay. The results show that 405, 633 and 785 nm laser irradiation induces wavelength-dependent and time-dependent proliferation. 633 nm laser irradiation results in a stimulatory proliferation effect that is most significant, whereas 514 nm laser irradiation produces little increase in cell proliferation. Low level laser irradiation increases cell proliferation in a dose-dependent manner. 1 000 J x m(-2) laser irradiation is more effective in increasing cell proliferation than 100 J x m(-2) laser irradiation using 405 nm diode laser, 633 nm He-Ne laser, or 785 nm diode laser, but not as effective as using 514 nm argon laser.

  7. 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

  8. 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

  9. Controversial effects of low level laser irradiation on the proliferation of human osteoblasts

    NASA Astrophysics Data System (ADS)

    Bölükbaşı Ateş, Gamze; Ak, Ayşe.; Garipcan, Bora; Yüksel, Šahru; Gülsoy, Murat

    2015-03-01

    Low level laser irradiation (LLLI) is the application of red or near infrared lasers irradiating between 600-1100 nm with an output power of 1-500 mW. Several researches indicate that LLLI modulates cellular mechanisms and leads to enhance proliferation. Although the biological mechanisms are not fully understood, it is known that the effects depend on several parameters such as wavelength, irradiation duration, energy level, beam type and energy density. The aim of this study is to investigate the effect of low level laser irradiation at varying energy densities with two different wavelengths (635 nm and 809 nm) on the proliferation of human osteoblasts in vitro. The cells are seeded on 96 well plates (105cells/well) and after 24 h incubation cells are irradiated at energy densities 0.5 J/cm2, 1 J/cm2 and 2 J/cm2. Cell viability test is applied after 24 h, 48 h and 72 h in order to examine effects of laser irradiation on osteoblast proliferation. 635 nm light irradiation did not appear to have significant effect on the proliferation of osteoblasts as compared to the control. On the other hand, 809 nm laser irradiation caused significant (p ≤ 0.01) biostimulation effect on the osteoblast cell cultures at 48 h and 72 h. In conclusion, irradiation of both wavelengths did not cause any cytotoxic effects. 809 nm light irradiation can promote proliferation of human osteoblasts in vitro. On the other hand, 635 nm light irradiation has no positive effect on osteoblast proliferation. As a result, LLLI applied using different wavelengths on the same cell type may lead to different biological effects.

  10. 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.

  11. 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.

  12. 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

    2016-07-26

    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.

  13. 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

  14. 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.

  15. Improving the electrical catalytic activity of Pt/TiO2 nanocomposites by a combination of electrospinning and microwave irradiation

    NASA Astrophysics Data System (ADS)

    Long, Qi; Cai, Mei; Li, Jinru; Rong, Huilin; Jiang, Long

    2011-04-01

    One of the greatest challenges in preparing TiO2-based oxygen electrodes for PEM fuel cells is increasing the electrical catalytic activity of Pt nanoparticle/TiO2 composites by improving the dispersion of Pt. This article describes a new way for improving the dispersion of Pt nanoparticles by depositing them on TiO2 fibers and using microwave irradiation. The Pt nanoparticles used in this experiment is about 5 nm in diameter and the diameter of TiO2 fibers could be controlled ranging from 30 to 60 nm and Pt nanoparticles still keep their size when the deposition amount is increased on the surface of TiO2 fibers. The Pt nanoparticles were highly dispersed without agglomeration even at a weight percentage of composites as high as 40%. The position of Pt nanoparticles located in the fiber and the composition of Pt/TiO2, which had great influence on the electric conductivity and electrical catalytic activity of the composite, could be easily controlled.

  16. 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.

  17. 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.

  18. 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.

  19. Low-level laser irradiation promotes the recovery of atrophied gastrocnemius skeletal muscle in rats.

    PubMed

    Nakano, Jiro; Kataoka, Hideki; Sakamoto, Jyunya; Origuchi, Tomoki; Okita, Minoru; Yoshimura, Toshiro

    2009-09-01

    Low-level laser (LLL) irradiation promotes proliferation of muscle satellite cells, angiogenesis and expression of growth factors. Satellite cells, angiogenesis and growth factors play important roles in the regeneration of muscle. The objective of this study was to examine the effect of LLL irradiation on rat gastrocnemius muscle recovering from disuse muscle atrophy. Eight-week-old rats were subjected to hindlimb suspension for 2 weeks, after which they were released and recovered. During the recovery period, rats underwent daily LLL irradiation (Ga-Al-As laser; 830 nm; 60 mW; total, 180 s) to the right gastrocnemius muscle through the skin. The untreated left gastrocnemius muscle served as the control. In conjunction with LLL irradiation, 5-bromo-2-deoxyuridine (BrdU) was injected subcutaneously to label the nuclei of proliferating cells. After 2 weeks, myofibre diameters of irradiated muscle increased in comparison with those of untreated muscle, but did not recover back to normal levels. Additionally, in the superficial region of the irradiated muscle, the number of capillaries and fibroblast growth factor levels exhibited significant elevation relative to those of untreated muscle. In the deep region of irradiated muscle, BrdU-positive nuclei of satellite cells and/or myofibres increased significantly relative to those of the untreated muscle. The results of this study suggest that LLL irradiation can promote recovery from disuse muscle atrophy in association with proliferation of satellite cells and angiogenesis.

  20. Ozone degradation of residual carbon in biological samples using microwave irradiation.

    PubMed

    Jiang, W; Chalk, S J; Kingston, H M

    1997-03-01

    In an attempt to produce complete oxidation of a biological matrix, bovine liver, ozone was investigated as an additional, potentially non-contaminating, oxidizing reagent after nitric acid digestion. Experiments were carried out to determine the decomposition efficiency of residual carbon species, primarily o-, m- and p-nitrobenzoic acids (NBAs), using ozone. The NBAs were degraded by purging sample digests with ozone, while heating the solutions with microwave energy at atmospheric pressure. The effects of the degradation temperature and solution pH on the ozonation of NBAs were determined. Solid phase extraction (C18) was used to extract NBAs from the acid digestate solutions prior to HPLC analysis. Reversed phase HPLC was used to determine NBA concentrations in digest solutions. After 2.5 h of purging ozone at 80 degrees C, 33.65 +/- 3.80% o-NBA degradation, 19.39 +/- 1.74% m-NBA degradation, and 26.47 +/- 3.36% p-NBA degradation were obtained.

  1. Doping dependent properties of Cr-doped ZnO nanostructures prepared by microwave irradiation.

    PubMed

    Ahmed, Faheem; Arshi, Nishat; Anwar, M S; Koo, Bon Heun

    2014-11-01

    In this work, undoped and Cr-doped single-crystalline ZnO nanorods were prepared by a facile microwave assisted solution method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that Cr-doped ZnO was comprised of single phase nature with hexagonal wurtzite structure up to 5% Cr doping, however, secondary phase ZnCr2O4 appeared upon further increasing the Cr dopant concentration. Field emission scanning electron microscopy (FESEM) and TEM micrographs suggested that the undoped nanorods with an average length of -~2 μm and a diameter in the range of 150-200 nm, respectively were observed. Interestingly, the size of nanorods decreased with the increase of Cr concentration in ZnO. Optical studies depicted that the energy bandgap was decreased with the increase of Cr concentration. Raman scattering spectra of Cr-doped ZnO revealed the lower frequency shift of E2(high) phonon mode with the increase in concentration of Cr dopant, suggested the successful doping of Cr into Zn site in ZnO. Magnetic studies showed that Cr-doped ZnO exhibited room temperature ferromagnetism (RTFM) and the value of magnetization was continuously decreased with the increase in Cr doping.

  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. Low Level Laser Irradiation of Nerve Cells In Vitro

    DTIC Science & Technology

    1996-01-01

    Advisor Michael Miloro, D.M.D., M.D. College of Dentistry ABSTRACT Low energy laser treatment of patients with nerve injuries has been reported to achieve...Isolation and Culture 15 vii Cell Lines 17 Cell Expansion 19 Cell Freezing 20 Experimental Design 20 GaA1As Laser Diode 22 Radiation Schedule 23...of 1 six well plate. Two groups served as controls. The remaining groups were irradiated with a 70 mW GaA1As laser diode , wavelength 820-830 nm

  4. 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.

  5. Microwave irradiation affects ion pairing in aqueous solutions of alkali halide salts

    NASA Astrophysics Data System (ADS)

    Mohorič, Tomaž; Bren, Urban

    2017-01-01

    Using the molecular dynamics simulations with separate thermostats for translational and rotational degrees of freedom, we investigate the effects of water's rotational motion on the ion pairing of ionic solutes in aqueous solutions. The situation with rotational temperature higher than the translational one, Trot>Ttrs , is mimicking the non-equilibrium effects of microwaves on model solutions of alkali halide salts. The simulations reveal that an increase in the rotational temperature at constant translational temperature exerts significant changes in the structure of the solution. The latter are reflected in increased pairing of the oppositely charged ions, which can be explained by the weaker ability of rotationally excited water to screen and separate the opposite charges. It seems that Collins' law of matching water affinities retains its validity also in the non-equilibrium situation where the rotational temperature exceeds the translational one. On the other hand, the equilibrium effect (i.e., an increase in the solution's overall temperature T ≡Trot = Ttrs) favors the formation of small-small (NaCl), while it has a little effect on large-large (CsI) ion pairs. This is in accordance with water becoming less polar solvent upon a temperature increase. Furthermore, we investigated the effects of excited translational motion of water (and ions) on the ion pairing by increasing the translational temperature, while keeping the rotational one unchanged (i.e., Ttrs>Trot ). Interestingly, in certain cases the faster translational motion causes an increase in correlations. The temperature variations in the like-ion association constants, Kas++ and Kas-, are also examined. Here the situation is more complex but, in most cases, a decrease in the ion pairing is observed.

  6. Transcranial low-level infrared laser irradiation ameliorates depression induced by reserpine in rats.

    PubMed

    Mohammed, Haitham S

    2016-11-01

    Transcranial low-level infrared laser is a modality of therapy based on the principle of photons delivered in a non-invasive manner through the skull for the treatment of some neurological conditions such as psychological disorders, traumatic brain injuries, and neurodegenerative diseases among others. In the present study, effects of low-level infrared laser irradiation with different radiation powers (80, 200, and 400 mW, continuous wave) were investigated on normal animals subjected to forced swimming test (FST). Results indicated that there are changes in FST parameters in animals irradiated with laser; the lowest dose provoked a significant increase in animal activity (swimming and climbing) and a significant decrease in animal's immobility, while the highest laser dose resulted in a complete inverse action by significantly increasing animal immobility and significantly decreasing animal activity with respect to control animals. The lowest dose (80 mW) of transcranial laser irradiation has then utilized on animals injected with a chronic dose of reserpine (0.2 mg/kg i.p. for 14 days) served as an animal model of depression. Laser irradiation has successfully ameliorated depression induced by reserpine as indicated by FST parameters and electrocorticography (ECoG) spectral analysis in irradiated animals. The findings of the present study emphasized the beneficial effects of low-level infrared laser irradiation on normal and healthy animals. Additionally, it indicated the potential antidepressant activity of the low dose of infrared laser irradiation.

  7. 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.

  8. Experimental study on an S-band near-field microwave magnetron power transmission system on hundred-watt level

    NASA Astrophysics Data System (ADS)

    Zhang, Biao; Jiang, Wan; Yang, Yang; Yu, Chengyang; Huang, Kama; Liu, Changjun

    2015-11-01

    A multi-magnetron microwave source, a metamaterial transmitting antenna, and a large power rectenna array are presented to build a near-field 2.45 GHz microwave power transmission system. The square 1 m2 rectenna array consists of sixteen rectennas with 2048 Schottky diodes for large power microwave rectifying. It receives microwave power and converts them into DC power. The design, structure, and measured performance of a unit rectenna as well as the entail rectenna array are presented in detail. The multi-magnetron microwave power source switches between half and full output power levels, i.e. the half-wave and full-wave modes. The transmission antenna is formed by a double-layer metallic hole array, which is applied to combine the output power of each magnetron. The rectenna array DC output power reaches 67.3 W on a 1.2 Ω DC load at a distance of 5.5 m from the transmission antenna. DC output power is affected by the distance, DC load, and the mode of microwave power source. It shows that conventional low power Schottky diodes can be applied to a microwave power transmission system with simple magnetrons to realise large power microwave rectifying.

  9. Power Spectrum Analysis and Missing Level Statistics of Microwave Graphs with Violated Time Reversal Invariance

    NASA Astrophysics Data System (ADS)

    Białous, Małgorzata; Yunko, Vitalii; Bauch, Szymon; Ławniczak, Michał; Dietz, Barbara; Sirko, Leszek

    2016-09-01

    We present experimental studies of the power spectrum and other fluctuation properties in the spectra of microwave networks simulating chaotic quantum graphs with violated time reversal invariance. On the basis of our data sets, we demonstrate that the power spectrum in combination with other long-range and also short-range spectral fluctuations provides a powerful tool for the identification of the symmetries and the determination of the fraction of missing levels. Such a procedure is indispensable for the evaluation of the fluctuation properties in the spectra of real physical systems like, e.g., nuclei or molecules, where one has to deal with the problem of missing levels.

  10. Power Spectrum Analysis and Missing Level Statistics of Microwave Graphs with Violated Time Reversal Invariance.

    PubMed

    Białous, Małgorzata; Yunko, Vitalii; Bauch, Szymon; Ławniczak, Michał; Dietz, Barbara; Sirko, Leszek

    2016-09-30

    We present experimental studies of the power spectrum and other fluctuation properties in the spectra of microwave networks simulating chaotic quantum graphs with violated time reversal invariance. On the basis of our data sets, we demonstrate that the power spectrum in combination with other long-range and also short-range spectral fluctuations provides a powerful tool for the identification of the symmetries and the determination of the fraction of missing levels. Such a procedure is indispensable for the evaluation of the fluctuation properties in the spectra of real physical systems like, e.g., nuclei or molecules, where one has to deal with the problem of missing levels.

  11. Microwave-assisted asymmetric organocatalysis. A probe for nonthermal microwave effects and the concept of simultaneous cooling.

    PubMed

    Hosseini, Masood; Stiasni, Nikola; Barbieri, Vera; Kappe, C Oliver

    2007-02-16

    A series of five known asymmetric organocatalytic reactions was re-evaluated at elevated temperatures applying both microwave dielectric heating and conventional thermal heating in order to probe the existence of specific or nonthermal microwave effects. All transformations were conducted in a dedicated reactor setup that allowed accurate internal reaction temperature measurements using fiber-optic probes. In addition, the concept of simultaneous external cooling while irradiating with microwave power was also applied in all of the studied cases. This method allows a higher level of microwave power to be administered to the reaction mixture and, therefore, enhances any potential microwave effects while continuously removing heat. For all of the five studied (S)-proline-catalyzed asymmetric Mannich- and aldol-type reactions, the observed rate enhancements were a consequence of the increased temperatures attained by microwave dielectric heating and were not related to the presence of the microwave field. In all cases, in contrast to previous literature reports, the results obtained either with microwave irradiation or with microwave irradiation with simultaneous cooling could be reproduced by conventional heating at the same reaction temperature and time in an oil bath. No evidence for specific or nonthermal microwave effects was obtained.

  12. Comparative effects of extremely high power microwave pulses and a brief CW irradiation on pacemaker function in isolated frog heart slices.

    PubMed

    Pakhomov, A G; Mathur, S P; Doyle, J; Stuck, B E; Kiel, J L; Murphy, M R

    2000-05-01

    The existence of specific bioeffects due to high peak power microwaves and their potential health hazards are among the most debated but least explored problems in microwave biology. The present study attempted to reveal such effects by comparing the bioeffects of short trains of extremely high power microwave pulses (EHPP, 1 micros width, 250-350 kW/g, 9.2 GHz) with those of relatively low power pulses (LPP, 0.5-10 s width, 3-30 W/g, 9.2 GHz). EHPP train duration and average power were made equal to those of an LPP; therefore both exposure modalities produced the same temperature rise. Bioeffects were studied in isolated, spontaneously beating slices of the frog heart. In most cases, a single EHPP train or LPP immediately decreased the inter-beat interval (IBI). The effect was proportional to microwave heating, fully reversible, and easily reproducible. The magnitude and time course of EHPP- and LPP-induced changes always were the same. No delayed or irreversible effects of irradiation were observed. The same effect could be repeated in a single preparation numerous times with no signs of adaptation, sensitization, lasting functional alteration, or damage. A qualitatively different effect, namely, a temporary arrest of preparation beats, could be observed when microwave heating exceeded physiologically tolerable limits. This effect also did not depend on whether the critical temperature rise was produced by LPP or EHPP exposure. Within the studied limits, we found no indications of EHPP-specific bioeffects. EHPP- and LPP-induced changes in the pacemaker rhythm of isolated frog heart preparation were identical and could be entirely attributed to microwave heating.

  13. 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.

  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. [The electroporation effects of high power pulse microwave and electromagnetic pulse irradiation on the membranes of cardiomyocyte cells and the mechanism therein involved].

    PubMed

    Deng, Hua; Wang, Dewen; Peng, Ruiyun; Wang, Shuiming; Chen, Jiankui; Zhang, Sa; Dong, Bo; Wang, Xiaomin

    2005-08-01

    Though there is ongoing public concern on potential hazards and risk of electromagnetic radiation, the bioeffects mechanism of electromagnetic fields remains obscure. Heart is one of the organs susceptive to electromagnetic fields (EMF). This study was designed to assess the influence of high power pulse microwave and electromagnetic pulse irradiation on cardiomyocytes, to explore the critical mechanism of electromagnetic fields, and to explain the regular course of injury caused by exposure to pulse EMF. Cultured cardiomyocytes were irradiated by high power pulse microwave and electromagnetic pulse first, then a series of apparatus including atom force microscope, laser scanning confocal microscope and flow cytometer were used to examine the changes of cell membrane conformation, structure and function. After irradiation, the cardiomyocytes pulsated slower or stop, the cells conformation was abnormal, the cells viability declined, and the percentage of apoptosis and necrosis increased significantly (P< 0.01). The cell membrane had pores unequal in size, and lost its penetration character. The concentration of Na+, K+, Ca2+, Cl-, Mg2+, Ca2+ and P3+ in cell culture medium increased significantly (P< 0.01). and the concentration of Ca2+ in cells ([Ca2+]i) decreased significantly (P<0.01). The results indicated that cardiomyocytes are susceptible to non-ionizing radiation. Pulse electromagnetic field can induce cardiomyocytes electroporation, and can do great damage to cells conformation, structure and function. Electroporation is one of the most critical mechanisms to explain the athermal effects of electromagnetic radiation.

  16. 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.

  17. Exocytosis sensitivity to growth hormone-releasing hormone in subsets of GH cells in rats under different corticosterone conditions. Ultrastructural study using microwave irradiation for fixation and immunocytochemistry.

    PubMed

    Ozawa, Hitoshi; Han, Fang; Kawata, Mitsuhiro

    2004-12-01

    Growth hormone (GH) cells in the rat anterior pituitary have been morphologically classified into three subtypes: type I (mature) containing large secretory granules about 350 nm in diameter, type II (intermediate) containing a mixture of large and small granules, and type III (immature) containing small granules about 150 nm in diameter. However, the functional implications of morphological heterogeneity, especially the different sensitivities to growth hormone-releasing hormone (GRH) under different corticosteroid conditions have not been elucidated to date. In the present study, by application of microwave irradiation (MWI) for fixation and immunocytochemistry, new findings of the exocytotic response have been revealed among the subsets of GH cells following adrenalectomy (ADX), corticosterone treatment and/or GRH treatment. The MWI gave effective results for fixation, especially for the permeability of the fixative, and showed good results for immunoelectron microscopy using the protein-A gold method. Moreover, the use of MWI greatly shortened the fixation, processing and immunolabeling times without compromising the quality of ultrastructural preservation and the specificity of labeling. The number of exocytotic figures was low in all subtypes of GH cells in the sham-operated control rats. GRH treatment induced a significant increase in exocytosis in each subtype of GH cells, particularly in type I (mature) and type II (intermediate) GH cells in the control rats. GRH injection to rats for 4 days after ADX also showed an increase in exocytosis, but the degree was significantly less in comparison with the GRH injection in the control group. Corticosterone replacement given to ADX rats induced a clear recovery of the exocytotic response to GRH to the control level. Serum GH content measured by radioimmunoassay correlated with these morphological results. These results suggest that the secretion of GH stimulated by GRH is closely related to corticosteroids, and

  18. Two-Dimensional Chirped-Pulse Fourier Transform Microwave Spectroscopy: Applications to Multi-Level Systems

    NASA Astrophysics Data System (ADS)

    Hotopp, Kelly M.; Wilcox, David S.; Shirar, Amanda J.; Dian, Brian C.

    2010-06-01

    Two-dimensional chirped-pulse Fourier transform microwave (CP-FTMW) spectroscopy has been used to study rotational energy level connectivity of 1,3-difluoroacetone and m-methylbenzaldehyde. In this series of experiments, non-selective polarizing pulse sequences were used to probe both progressively and regressively connected systems through coherences of coupled rotational energy levels. Coherence propagation among shared energy levels will be demonstrated on 1,3-difluoroacetone. Ab initio calculations predict that the methyl rotor barrier of m-methylbenzaldehyde is less than 35 cm-1 therefore giving rise to large A-E splitting. Furthermore there are two conformers of m-methylbenzaldehyde making the assignment of the rotational spectrum extremely difficult. We will show how coherence propagation demonstrated by 1,3-difluoroacetone can be applied in a general way to assign complex ground state rotational spectra such as m-methylbenzaldehyde.

  19. Detection of Low Level Microwave Radiation Induced Deoxyribonucleic Acid Damage Vis-à-vis Genotoxicity in Brain of Fischer Rats

    PubMed Central

    Deshmukh, Pravin Suryakantrao; Megha, Kanu; Banerjee, Basu Dev; Ahmed, Rafat Sultana; Chandna, Sudhir; Abegaonkar, Mahesh Pandurang; Tripathi, Ashok Kumar

    2013-01-01

    Background: Non-ionizing radiofrequency radiation has been increasingly used in industry, commerce, medicine and especially in mobile phone technology and has become a matter of serious concern in present time. Objective: The present study was designed to investigate the possible deoxyribonucleic acid (DNA) damaging effects of low-level microwave radiation in brain of Fischer rats. Materials and Methods: Experiments were performed on male Fischer rats exposed to microwave radiation for 30 days at three different frequencies: 900, 1800 and 2450 MHz. Animals were divided into 4 groups: Group I (Sham exposed): Animals not exposed to microwave radiation but kept under same conditions as that of other groups, Group II: Animals exposed to microwave radiation at frequency 900 MHz at specific absorption rate (SAR) 5.953 × 10−4 W/kg, Group III: Animals exposed to 1800 MHz at SAR 5.835 × 10−4 W/kg and Group IV: Animals exposed to 2450 MHz at SAR 6.672 × 10−4 W/kg. At the end of the exposure period animals were sacrificed immediately and DNA damage in brain tissue was assessed using alkaline comet assay. Results: In the present study, we demonstrated DNA damaging effects of low level microwave radiation in brain. Conclusion: We concluded that low SAR microwave radiation exposure at these frequencies may induce DNA strand breaks in brain tissue. PMID:23833433

  20. Low-level visible light (LLVL) irradiation promotes proliferation of mesenchymal stem cells.

    PubMed

    Lipovsky, Anat; Oron, Uri; Gedanken, Aharon; Lubart, Rachel

    2013-07-01

    Low-level visible light irradiation was found to stimulate proliferation potential of various types of cells in vitro. Stem cells in general are of significance for implantation in regenerative medicine. The aim of the present study was to investigate the effect of low-level light irradiation on the proliferation of mesenchymal stem cells (MSCs). MSCs were isolated from the bone marrow, and light irradiation was applied at energy densities of 2.4, 4.8, and 7.2 J/cm(2). Illumination of the MSCs resulted in almost twofold increase in cell number as compared to controls. Elevated reactive oxygen species and nitric oxide production was also observed in MSCs cultures following illumination with broadband visible light. The present study clearly demonstrates the ability of broadband visible light illumination to promote proliferation of MSCs in vitro. These results may have an important impact on wound healing.

  1. Microwave irradiation induced changes in protein molecular structures of barley grains: relationship to changes in protein chemical profile, protein subfractions, and digestion in dairy cows.

    PubMed

    Yan, Xiaogang; Khan, Nazir A; Zhang, Fangyu; Yang, Ling; Yu, Peiqiang

    2014-07-16

    The objectives of this study were to evaluate microwave irradiation (MIR) induced changes in crude protein (CP) subfraction profiles, ruminal CP degradation characteristics and intestinal digestibility of rumen undegraded protein (RUP), and protein molecular structures in barley (Hordeum vulgare) grains. Samples from hulled (n = 1) and hulless cultivars (n = 2) of barley, harvested from four replicate plots in two consecutive years, were evaluated. The samples were either kept as raw or irradiated in a microwave for 3 min (MIR3) or 5 min (MIR5). Compared to raw grains, MIR5 decreased the contents of rapidly degradable CP subfraction (from 45.22 to 6.36% CP) and the ruminal degradation rate (from 8.16 to 3.53%/h) of potentially degradable subfraction. As a consequence, the effective ruminal degradability of CP decreased (from 55.70 to 34.08% CP) and RUP supply (from 43.31 to 65.92% CP) to the postruminal tract increased. The MIR decreased the spectral intensities of amide 1, amide II, α-helix, and β-sheet and increased their ratios. The changes in protein spectral intensities were strongly correlated with the changes in CP subfractions and digestive kinetics. These results show that MIR for a short period (5 min) with a lower energy input can improve the nutritive value and utilization of CP in barely grains.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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).

  7. 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

  8. Utilizing commercial microwave for rapid and effective immunostaining.

    PubMed

    Owens, Katrina; Park, Ji H; Kristian, Tibor

    2013-09-30

    There is an accumulating literature demonstrating the application of microwaves across a wide spectrum of histological techniques. Although exposure to microwaves for short periods resulted in substantial acceleration of all procedures this technique still is not adopted widely. In part, this may be due to concerns over solutions that will avoid induction of thermal damage to the tissue when using standard microwave. Here, we offer a cooling setup that can be used with conventional microwave ovens. We utilized dry ice for effective cooling during microwave irradiation of tissue samples. To prevent overheating, the cups with tissue during exposure to microwaves were surrounded with powdered dry ice. Since the dry ice does not touch the walls of the cups, freezing is prevented. Overheating is avoided by alternating the microwave treatment with 1-2 min time periods when the cups are cooled outside of the microwave oven. This technique was used on mouse brain sections that were immunostained with microglia-specific CD68 antiserum and astrocyte labeling GFAP antibody. Both standard and microwave-assisted immonolabeling gave comparable results visualizing cells with fine processes and low background signal. Short incubation time in the microwave requires high concentrations of antibody for tissue immunostaining. We show that by prolonging the microwaving procedure we were able to reduce the antibody concentration to the levels used in standard immunostaining protocol. In summary, our technique gives a possibility to use a conventional microwave for rapid and effective immunolabeling resulting in reduced amount of antibody required for satisfactory immunostaining.

  9. 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.

  10. 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

  11. 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.

  12. Deep levels induced by high fluence proton irradiation in undoped GaAs diodes

    SciTech Connect

    Castaldini, A.; Cavallini, A.; Polenta, L.; Canali, C.; Nava, F.; Ferrini, R.; Galli, M.

    1998-12-31

    Semi-insulating liquid encapsulated Czochralski grown GaAs has been investigated after irradiation at high fluences of high-energy protons. Electron beam induced current observations of scanning electron microscopy evidenced a radiation stimulated ordering. An analysis has been carried out of the deep levels associated with defects as a function of the irradiation fluence, using complementary current transient spectroscopies. By increasing the irradiation fluence, the concentration of the native traps at 0.37 eV together with that of the EL2 defect significantly increases and, at the same time, two new electron traps at 0.15 eV and 0.18 eV arise and quickly increase in density.

  13. 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.

  14. 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.

  15. 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.

  16. Microwave Limb Sounder Measurements Depicting the Relationship Between Nitrous Oxide Levels and

    NASA Technical Reports Server (NTRS)

    2005-01-01

    Aura's Microwave Limb Sounder measures nitrous oxide, which is unaffected by stratospheric chemical processes. By studying changes in its levels, scientists can better understand how air is moving around and how ozone is affected by that air motion, allowing them to differentiate those changes from the ones caused by chemical ozone destruction. In these cross-sections of nitrous oxide (top) and ozone (bottom) data from Aura, changes in the levels of these two chemicals at various temperatures and latitudes are depicted over time. The white contour shows the approximate location of the polar vortex boundary.

    The left panel data were collected on January 23, 2005, near the beginning of chemical ozone destruction this winter. Virtually all chemical loss occurred before March 10 (center panel). Ozone destruction extended throughout the polar vortex from about 15-20 kilometers (9-13 miles), but occurred only in the outer part of the vortex from 20-25 kilometers (13-16 miles). The differences between the two days are depicted in the right panel. The largest observed difference is about a 1.2 parts per million by volume decrease in ozone. Plots of nitrous oxide show a decrease in the region in the outer part of the vortex where most ozone loss occurs, indicating that air from above (where nitrous oxide is lower) has moved into this region. This downward motion brings higher ozone into the region where chemical loss is occurring, thus partially masking the effects of chemical loss. Calculations using Microwave Limb Sounder data to separate dynamical and chemical effects indicate maximum chemical ozone loss of approximately 2 parts per million by volume (approximately 60 percent) in the outer part of the vortex near 18-21 kilometers (11-13 miles), and approximately 1.5 parts per million by volume when averaged throughout the whole vortex region.

  17. Self-sacrificial templating synthesis of porous quaternary Cu-Fe-Sn-S semiconductor nanotubes via microwave irradiation.

    PubMed

    Ai, Lunhong; Jiang, Jing

    2012-12-14

    Uniform quaternary Cu(2)FeSnS(4) (CITS) nanotubes of outer diameter 400-800 nm and thickness 100-200 nm have been synthesized for the first time by a simple, rapid and easily scaled-up microwave nonaqueous route using benzyl alcohol as the microwave absorbing solvent. An interesting in situ generated one-dimensional Cu(Tu)Cl nanorod acting as a self-sacrificial template was crucial for the formation of the well-defined CITS nanotubes. Based on the designed time-dependent experiments, a formation mechanism for the CITS nanotubes was also proposed. The resulting CITS nanotubes had a strong absorption in the visible region with a bandgap of 1.71 eV that was optimal for photovoltaic applications. Our study provided a microwave nonaqueous route generally applicable for the synthesis of quaternary chalcogenide semiconductor nanotubes.

  18. 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.

  19. Large lattice relaxation deep levels in neutron-irradiated GaN

    NASA Astrophysics Data System (ADS)

    Li, S.; Zhang, J. D.; Beling, C. D.; Wang, K.; Wang, R. X.; Gong, M.; Sarkar, C. K.

    2005-11-01

    Deep level transient spectroscopy (DLTS) and deep level optical spectroscopy (DLOS) measurements have been carried out in neutron-irradiated n-type hydride-vapor-phase-epitaxy-grown GaN. A defect center characterized by a DLTS line, labeled as N1, is observed at EC-ET=0.17 eV. Another line, labeled as N2, at EC-ET=0.23 eV, seems to be induced at the same rate as N1 under irradiation and may be identified with E1. Other defects native to wurtzite GaN such as the C and E2 lines appear to enhance under neutron irradiation. The DLOS results show that the defects N1 and N2 have large Frank-Condon shifts of 0.64 and 0.67 eV, respectively, and hence large lattice relaxations. The as-grown and neutron-irradiated samples all exhibit the persistent photoconductivity effect commonly seen in GaN that may be attributed to DX centers. The concentration of the DX centers increases significantly with neutron dosage and is helpful in sustaining sample conductivity at low temperatures, thus making possible DLTS measurements on N1 an N2 in the radiation-induced deep-donor defect compensated material which otherwise are prevented by carrier freeze-out.

  20. P-type nitrogen-doped ZnO nanostructures with controlled shape and doping level by facile microwave synthesis.

    PubMed

    Herring, Natalie P; Panchakarla, Leela S; El-Shall, M Samy

    2014-03-04

    We report herein the development of a facile microwave irradiation (MWI) method for the synthesis of high-quality N-doped ZnO nanostructures with controlled morphology and doping level. We present two different approaches for the MWI-assisted synthesis of N-doped ZnO nanostructures. In the first approach, N-doping of Zn-poor ZnO prepared using zinc peroxide (ZnO2) as a precursor is carried out under MWI in the presence of urea as a nitrogen source and oleylamine (OAm) as a capping agent for the shape control of the resulting N-doped ZnO nanostructures. Our approach utilizes the MWI process for the decomposition of ZnO2, where the rapid transfer of energy directly to ZnO2 can cause an instantaneous internal temperature rise and, thus, the activation energy for the ZnO2 decomposition is essentially decreased as compared to the decomposition under conductive heating. In the second synthesis method, a one-step synthesis of N-doped ZnO nanostructures is achieved by the rapid decomposition of zinc acetate in a mixture of urea and OAm under MWI. We demonstrate, for the first time, that MWI decomposition of zinc acetate in a mixture of OAm and urea results in the formation of N-doped nanostructures with controlled shape and N-doping level. We report a direct correlation between the intensity of the Raman scattering bands in N-doped ZnO and the concentration of urea used in the synthesis. Electrochemical measurements demonstrate the successful synthesis of stable p-type N-doped ZnO nanostructures using the one-step MWI synthesis and, therefore, allow us to investigate, for the first time, the relationship between the doping level and morphology of the ZnO nanostructures. The results provide strong evidence for the control of the electrical behavior and the nanostructured shapes of ZnO nanoparticles using the facile MWI synthesis method developed in this work.

  1. 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

  2. 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.

  3. 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.

  4. Efficient pallado-catalyzed C6-(het)arylation of Imidazo[1,2-b][1,2,4,5]tetrazines under microwave irradiations.

    PubMed

    Pellegatti, Laurent; Vedrenne, Emeline; Leger, Jean-Michel; Jarry, Christian; Routier, Sylvain

    2010-07-12

    A versatile protocol for the preparation of a library of 5,6-(het)bisarylated imidazo[1,2-b][1,2,4,5]tetrazines is described. Target compounds were obtained in fairly good yields, starting from ethoxy-7-(4-methoxyphenyl)imidazo[1,2-b][1,2,4,5]tetrazine and a large panel of bromoaryl derivatives, using palladium catalysis under microwave irradiation. Compatibility with various chemical groups and heterocycles was proven. Steric and electronic effects do not have any effect on the efficiency of the reaction. Purifications were performed without any difficulties, and the structure of a final compound was proven by crystal X-ray diffraction studies.

  5. Chiral recyclable dimeric and polymeric Cr(III) salen complexes catalyzed aminolytic kinetic resolution of trans-aromatic epoxides under microwave irradiation.

    PubMed

    Kureshy, Rukhsana I; Prathap, K Jeya; Singh, Surendra; Agrawal, Santosh; Khan, Noor-Ul H; Abdi, Sayed H R; Jasra, Raksh V

    2007-11-01

    Aminolytic kinetic resolution (AKR) of trans-stilbene oxide and trans-beta-methyl styrene oxide proceeded smoothly under microwave irradiation using chiral dimeric and polymeric Cr(III) salen complexes as efficient catalysts, giving regio-, diastereo-, and enantioselective anti-beta-amino alcohols in high yields (49%) and chiral purity (ee up to 94%) in case of 4-methylaniline within 2 min. The kinetic resolution system is approximately five times faster than traditional oil bath heating at 70 degrees C and 420 times faster than the reaction conducted at room temperature with concomitant recovery of respective chirally enriched epoxides (ee, 92%) in excellent yields (up to 48%). The catalyst 1 worked well in terms of enantioselectivity than the catalyst 2, but both the catalysts were easily recovered and reused five times with the retention of its efficiency.

  6. 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.

  7. 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).

  8. 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.

  9. High-frequency low-level diode laser irradiation promotes proliferation and migration of primary cultured human gingival epithelial cells.

    PubMed

    Ejiri, Kenichiro; Aoki, Akira; Yamaguchi, Yoko; Ohshima, Mitsuhiro; Izumi, Yuichi

    2014-07-01

    In periodontal therapy, the use of low-level diode lasers has recently been considered to improve wound healing of the gingival tissue. However, its effects on human gingival epithelial cells (HGECs) remain unknown. The aim of the present study was to examine whether high-frequency low-level diode laser irradiation stimulates key cell responses in wound healing, proliferation and migration, in primary cultured HGECs in vitro. HGECs were derived from seven independent gingival tissue specimens. Cultured HGECs were exposed to a single session of high-frequency (30 kHz) low-level diode laser irradiation with various irradiation time periods (fluence 5.7-56.7 J/cm(2)). After 20-24 h, cell proliferation was evaluated by WST-8 assay and [(3)H]thymidine incorporation assay, and cell migration was monitored by in vitro wound healing assay. Further, phosphorylation of the mitogen-activated protein kinase (MAPK) pathways after irradiation was investigated by Western blotting. The high-frequency low-level irradiation significantly increased cell proliferation and [(3)H]thymidine incorporation at various irradiation time periods. Migration of the irradiated cells was significantly accelerated compared with the nonirradiated control. Further, the low-level diode laser irradiation induced phosphorylation of MAPK/extracellular signal-regulated protein kinase (ERK) at 5, 15, 60, and 120 min after irradiation. Stress-activated protein kinases/c-Jun N-terminal kinase and p38 MAPK remained un-phosphorylated. The results show that high-frequency low-level diode laser irradiation promotes HGEC proliferation and migration in association with the activation of MAPK/ERK, suggesting that laser irradiation may accelerate gingival wound healing.

  10. Selection of Lipases for the Synthesis of Biodiesel from Jatropha Oil and the Potential of Microwave Irradiation to Enhance the Reaction Rate

    PubMed Central

    2016-01-01

    The present study deals with the enzymatic synthesis of biodiesel by transesterification of Jatropha oil (Jatropha curcas L.) with ethanol in a solvent-free system. Seven commercial lipase preparations immobilized by covalent attachment on epoxy-polysiloxane-polyvinyl alcohol composite (epoxy-SiO2-PVA) were tested as biocatalysts. Among them, immobilized lipases from Pseudomonas fluorescens (lipase AK) and Burkholderia cepacia (lipase PS) were the most active biocatalysts in biodiesel synthesis, reaching ethyl ester yields (FAEE) of 91.1 and 98.3% at 72 h of reaction, respectively. The latter biocatalyst exhibited similar performance compared to Novozym® 435. Purified biodiesel was characterized by different techniques. Transesterification reaction carried out under microwave irradiation exhibited higher yield and productivity than conventional heating. The operational stability of immobilized lipase PS was determined in repeated batch runs under conventional and microwave heating systems, revealing half-life times of 430.4 h and 23.5 h, respectively. PMID:27868060

  11. 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}.

  12. Low-level laser irradiation stimulates tenocyte migration with up-regulation of dynamin II expression.

    PubMed

    Tsai, Wen-Chung; Hsu, Chih-Chin; Pang, Jong-Hwei S; Lin, Miao-Sui; Chen, Ying-Hsun; Liang, Fang-Chen

    2012-01-01

    Low-level laser therapy (LLLT) is commonly used to treat sports-related tendinopathy or tendon injury. Tendon healing requires tenocyte migration to the repair site, followed by proliferation and synthesis of the extracellular matrix. This study was designed to determine the effect of laser on tenocyte migration. Furthermore, the correlation between this effect and expression of dynamin 2, a positive regulator of cell motility, was also investigated. Tenocytes intrinsic to rat Achilles tendon were treated with low-level laser (660 nm with energy density at 1.0, 1.5, and 2.0 J/cm(2)). Tenocyte migration was evaluated by an in vitro wound healing model and by transwell filter migration assay. The messenger RNA (mRNA) and protein expressions of dynamin 2 were determined by reverse transcription/real-time polymerase chain reaction (real-time PCR) and Western blot analysis respectively. Immunofluorescence staining was used to evaluate the dynamin 2 expression in tenocytes. Tenocytes with or without laser irradiation was treated with dynasore, a dynamin competitor and then underwent transwell filter migration assay. In vitro wound model revealed that more tenocytes with laser irradiation migrated across the wound border to the cell-free zone. Transwell filter migration assay confirmed that tenocyte migration was enhanced dose-dependently by laser. Real-time PCR and Western-blot analysis demonstrated that mRNA and protein expressions of dynamin 2 were up-regulated by laser irradiation dose-dependently. Confocal microscopy showed that laser enhanced the expression of dynamin 2 in cytoplasm of tenocytes. The stimulation effect of laser on tenocytes migration was suppressed by dynasore. In conclusion, low-level laser irradiation stimulates tenocyte migration in a process that is mediated by up-regulation of dynamin 2, which can be suppressed by dynasore.

  13. Application of D-optimal design to extract the pectin from lime bagasse using microwave green irradiation.

    PubMed

    Thirugnanasambandham, K; Sivakumar, V

    2015-01-01

    The main objective of the present study is to extract the pectin from lime bagasse under various extraction conditions such as microwave power, extraction time, temperature, pH and mass of the sample. RSM coupled with D-optimal experimental design was used to optimize and investigate the extraction conditions on the pectin yield. Second order polynomial equation was developed and its adequacy was analyzed by analysis of variance (ANOVA). The optimal extraction was found to be as follows; microwave power of 400 W, extraction time of 500 s, temperature of 30 °C, pH of 1 and mass of the sample of 6g. Under these optimal scheme, 7.8 g/100g of pectin was extracted. Molecular weight of the pectin polymer and the distribution of the pectin compounds were determined by gel filtration chromatography.

  14. 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.

  15. A process to preserve valuable compounds and acquire essential oils from pomelo flavedo using a microwave irradiation treatment.

    PubMed

    Liu, Zaizhi; Zu, Yuangang; Yang, Lei

    2017-06-01

    A microwave pretreatment method was developed to preserve pectin, naringin, and limonin contents in pomelo flavedo to allow for longer storage times and subsequent extraction of pomelo essential oil. In terms of the essential oil, microwave pretreatment performed better than hydrodistillation with respect to extraction efficiency (1.88±0.06% in 24min versus 1.91±0.08% in 240min), oxygenation fraction (48.59±1.32% versus 29.63±1.02%), energy consumption (0.15kWh versus 1.54kWh), and environmental impact (123.20g CO2 versus 1232g CO2). Microwave-pretreated samples retained higher amounts of pectin, naringin, and limonin compared with non-pretreated samples. No obvious change in the degree of pectin esterification was observed. This study shows that the proposed process is a promising methodology for both preserving valuable compounds in pomelo flavedo during storage and acquiring essential oils.

  16. Confirmation of hydroxyl radicals (•OH) generated in the presence of TiO2 supported on AC under microwave irradiation.

    PubMed

    Zhang, Zhaohong; Yu, Fengyang; Huang, Lirong; Jiatieli, Jianaerguli; Li, Yuanyuan; Song, Lijun; Yu, Ning; Dionysiou, Dionysios D

    2014-08-15

    In order to study the degradation mechanism of technology of microwave (MW) combined with TiO2 supported on activated carbon (TiO2/AC), the reactive oxygen species (ROS) was explored through oxidation of 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). Furthermore, 2,6-di-tert-butyl-4-methylphenol (BHT), Mannitol (MT) and Vitamin C (VC) were used as radical scavengers to confirm the generation of the hydroxyl radicals ((•)OH). In addition, the influence of some parameters such as TiO2 mass ratio content, irradiation time, material dose, DPCI concentration and MW power on the determination of (•)OH were examined. The results showed that the (•)OH could be generated under MW combined with loaded TiO2/AC. Also, anatase TiO2/AC can generate more (•)OH radicals than rutile TiO2/AC under MW irradiation. This work would provide new mechanistic insights on the enhanced degradation effect of organic pollutants in water using the supported TiO2/AC coupled with MW technology.

  17. 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.

  18. 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.

  19. Superoxide dismutase levels in various radioresistant and radiosensitive tissues of irradiated rats.

    PubMed

    Krízala, J; Kovárová, H; Stoklasová, A; Ledvina, M

    1982-01-01

    The activity of superoxide dismutase (E.C. 1.15.1.1; SOD) was determined in male Wistar rats in order to evaluate the possible relationship between both the enzyme content in tissue and the resistance of this tissue to ionizing radiation (8,0 Gy, 60Co). Our results showed that some non-irradiated radioresistant organs (liver) had a high SOD activity and on the contrary, in some radiosensitive tissue (bone marrow) the SOD content was low. In spite of this observation it is not possible to generalize the statement that the radiosensitivity is directly conditioned by the SOD level without any exception. The SOD content in the spleen was higher than in the brain, but the spleen is remarkably radiosensitive, whereas the brain is not. The radiosensitivity of individual tissues probably reflected the changes of SOD activity after the irradiation.

  20. 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.

  1. 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.

  2. 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

    2014-12-09

    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.

  3. Spontaneous emission from a microwave-driven four-level atom in an anisotropic photonic crystal

    NASA Astrophysics Data System (ADS)

    Jiang, Li; Wan, Ren-Gang; Yao, Zhi-Hai

    2016-10-01

    The spontaneous emission from a microwave-driven four-level atom embedded in an anisotropic photonic crystal is studied. Due to the modified density of state (DOS) in the anisotropic photonic band gap (PBG) and the coherent control induced by the coupling fields, spontaneous emission can be significantly enhanced when the position of the spontaneous emission peak gets close to the band gap edge. As a result of the closed-loop interaction between the fields and the atom, the spontaneous emission depends on the dynamically induced Autler-Townes splitting and its position relative to the PBG. Interesting phenomena, such as spectral-line suppression, enhancement and narrowing, and fluorescence quenching, appear in the spontaneous emission spectra, which are modulated by amplitudes and phases of the coherently driven fields and the effect of PBG. This theoretical study can provide us with more efficient methods to manipulate the atomic spontaneous emission. Project supported by the National Natural Science Foundation of China (Grant Nos. 11447232, 11204367, 11447157, and 11305020).

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

    PubMed Central

    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

  5. 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

  6. DLTS study of deep level defects in Li-ion irradiated bipolar junction transistor

    NASA Astrophysics Data System (ADS)

    Madhu, K. V.; Kulkarni, S. R.; Ravindra, M.; Damle, R.

    2007-01-01

    Commercial npn transistor (2N 2219A) irradiated with 50 MeV Li 3+-ions with fluences ranging from 3.1 × 10 13 ions cm -2 to 12.5 × 10 13 ions cm -2, is studied for radiation induced gain degradation and minority carrier trap levels or recombination centers. The properties such as activation energy, trap concentration and capture cross section of induced deep levels are studied by deep level transient spectroscopy (DLTS) technique. Minority carrier trap levels with energies ranging from 0.237 eV to 0.591 eV were observed in the base-collector junction of the transistor. In situ I- V measurements were made to study the gain degradation as a function of ion fluence. Ion induced energy levels result in increase in the base current through Shockley Read Hall (SRH) or multi-phonon recombination and subsequent transistor gain degradation.

  7. 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

  8. Levels of 2-dodecylcyclobutanone in ground beef patties irradiated by low-energy X-ray and gamma rays.

    PubMed

    Hijaz, Faraj M; Smith, J Scott

    2010-01-01

    Food irradiation improves food safety and maintains food quality by controlling microorganisms and extending shelf life. However, acceptance and commercial adoption of food irradiation is still low. Consumer groups such as Public Citizen and the Food and Water Watch have opposed irradiation because of the formation of 2-alkylcyclobutanones (2-ACBs) in irradiated, lipid-containing foods. The objectives of this study were to measure and to compare the level of 2-dodecylcyclobutanone (2-DCB) in ground beef irradiated by low-energy X-rays and gamma rays. Beef patties were irradiated by low-energy X-rays and gamma rays (Cs-137) at 3 targeted absorbed doses of 1.5, 3.0, and 5.0 kGy. The samples were extracted with n-hexane using a Soxhlet apparatus, and the 2-DCB concentration was determined with gas chromatography-mass spectrometry. The 2-DCB concentration increased linearly (P < 0.05) with irradiation dose for gamma-ray and low-energy X-ray irradiated patties. There was no significant difference in 2-DCB concentration between gamma-ray and low-energy X-ray irradiated patties (P > 0.05) at all targeted doses.

  9. 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.

  10. 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.

  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. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Synthetic Development of New 3-(4-Arylmethylamino)butyl-5-arylidene-rhodanines under Microwave Irradiation and Their Effects on Tumor Cell Lines and against Protein Kinases.

    PubMed

    Dago, Camille Déliko; Ambeu, Christelle N'ta; Coulibaly, Wacothon-Karime; Békro, Yves-Alain; Mamyrbékova, Janat; Defontaine, Audrey; Baratte, Blandine; Bach, Stéphane; Ruchaud, Sandrine; Guével, Rémy Le; Ravache, Myriam; Corlu, Anne; Bazureau, Jean-Pierre

    2015-07-08

    A new route to 3-(4-arylmethylamino)butyl-5-arylidene-2-thioxo-1,3-thiazolidine-4-one 9 was developed in six steps from commercial 1,4-diaminobutane 1 as starting material. The key step of this multi-step synthesis involved a solution phase "one-pot two-steps" approach assisted by microwave dielectric from N-(arylmethyl)butane-1,4-diamine hydrochloride 6a-f (as source of the first point diversity) and commercial bis-(carboxymethyl)-trithiocarbonate reagent 7 for construction of the rhodanine platform. This platform was immediately functionalized by Knoevenagel condensation under microwave irradiation with a series of aromatic aldehydes 3 as second point of diversity. These new compounds were prepared in moderate to good yields and the fourteen synthetic products 9a-n have been obtained with a Z-geometry about their exocyclic double bond. These new 5-arylidene rhodanines derivatives 9a-n were tested for their kinase inhibitory potencies against four protein kinases: Human cyclin-dependent kinase 5-p25, HsCDK5-p25; porcine Glycogen Synthase Kinase-3, GSK-3α/β; porcine Casein Kinase 1, SsCK1 and human HsHaspin. They have also been evaluated for their in vitro inhibition of cell proliferation (HuH7 D12, Caco 2, MDA-MB 231, HCT 116, PC3, NCI-H727, HaCat and fibroblasts). Among of all these compounds, 9j presented selective micromolar inhibition activity on SsCK1 and 9i exhibited antitumor activities in the HuH7 D12, MDA-MBD231 cell lines.

  17. Reduction in horizontal transfer of conjugative plasmid by UV irradiation and low-level chlorination.

    PubMed

    Lin, Wenfang; Li, Shuai; Zhang, Shuting; Yu, Xin

    2016-03-15

    The widespread presence of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) in the drinking water system facilitates their horizontal gene transfer among microbiota. In this study, the conjugative gene transfer of RP4 plasmid after disinfection including ultraviolet (UV) irradiation and low-level chlorine treatment was investigated. It was found that both UV irradiation and low-level chlorine treatment reduced the conjugative gene transfer frequency. The transfer frequency gradually decreased from 2.75 × 10(-3) to 2.44 × 10(-5) after exposure to UV doses ranging from 5 to 20 mJ/cm(2). With higher UV dose of 50 and 100 mJ/cm(2), the transfer frequency was reduced to 1.77 × 10(-6) and 2.44 × 10(-8). The RP4 plasmid transfer frequency was not significantly affected by chlorine treatment at dosages ranging from 0.05 to 0.2 mg/l, but treatment with 0.3-0.5 mg/l chlorine induced a decrease in conjugative transfer to 4.40 × 10(-5) or below the detection limit. The mechanisms underlying these phenomena were also explored, and the results demonstrated that UV irradiation and chlorine treatment (0.3 and 0.5 mg/l) significantly reduced the viability of bacteria, thereby lowering the conjugative transfer frequency. Although the lower chlorine concentrations tested (0.05-0.2 mg/l) were not sufficient to damage the cells, exposure to these concentrations may still depress the expression of a flagellar gene (FlgC), an outer membrane porin gene (ompF), and a DNA transport-related gene (TraG). Additionally, fewer pili were scattered on the bacteria after chlorine treatment. These findings are important in assessing and controlling the risk of ARG transfer and dissemination in the drinking water system.

  18. Microwave heating characteristics of magnetite ore

    NASA Astrophysics Data System (ADS)

    Rajavaram, Ramaraghavulu; Lee, Jaehong; Oh, Joon Seok; Kim, Han Gyeol; Lee, Joonho

    2016-11-01

    The heating characteristics of magnetite ore under microwave irradiation were investigated as a function of incident microwave power, particle size, and magnetite ore mass. The results showed that the heating rate of magnetite ore is highly dependent on microwave power and magnetite ore mass. The maximum heating rate was obtained at a microwave irradiation power of 1.70 kW with a mass of 25 g and particle size between 53-75 µm. The volumetric heating rate of magnetite ore was investigated by measuring the temperature at different depths during microwave irradiation. Microwave irradiation resulted in modification of the microstructure of the magnetite ore, but new phases such as FeO or Fe2O3 were not formed. In addition, the crystal size decreased from 115 nm to 63 nm after microwave irradiation up to 1573 K.

  19. Facile synthesis of 1,3,4-benzotriazepines and 1-arylamide-1H-indazoles via palladium-catalyzed cyclization of aryl isocyanates and aryl hydrazones under microwave irradiation.

    PubMed

    Dong, Chune; Xie, Lingli; Mou, Xiaohong; Zhong, Yashan; Su, Wei

    2010-11-07

    A strategy involving palladium-catalyzed cyclization of halo-phenyl hydrazones and aryl isocyanates provides a convenient approach to the synthesis of 1,3,4-benzotriazepines (4) or 1-arylamide-1H-indazoles (5) in good isolated yields. Microwave irradiation was found to afford high reaction efficiency, while the choice of halophenyl hydrazone had an effect on the pathway of the reaction.

  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. Influences of doping Cr/Fe/Ta on the performance of Ni/CeO{sub 2} catalyst under microwave irradiation in dry reforming of CH{sub 4}

    SciTech Connect

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

    2016-01-15

    The structure of Ni/CeO{sub 2} catalyst with doping of Cr, Fe and Ta was investigated with XRD, N{sub 2} 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/CeO{sub 2} can enhance the interaction between Ni and the support/promoter and inhibit the enlargement of NiO particles during the synthesis. The CH{sub 4} conversions in dry reforming on the catalysts follow the order: Ni/CeO{sub 2}<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. - Highlights: • The influences of doping Cr, Fe and Ta on Ni/CeO{sub 2} were investigated. • The catalytic performances before and after doping were investigated. • The in-situ grown graphene can promote the conversion of reactants.

  2. Microwave-immobilized polybutadiene stationary phase for reversed-phase high-performance liquid chromatography.

    PubMed

    Lopes, Nilva P; Collins, Kenneth E; Jardim, Isabel C S F

    2004-03-19

    Polybutadiene (PBD) has been immobilized on high-performance liquid chromatography (HPLC) silica by microwave radiation at various power levels (52-663 W) and actuation times (3-60 min). Columns prepared from these reversed-phase HPLC materials, as well as from similar non-irradiated materials, were tested with standard sample mixtures and characterized by elemental analysis (%C) and infrared spectroscopy. A microwave irradiation of 20 min at 663 W gives a layer of immobilized PBD that presented good performance. Longer irradiation times give thicker immobilized layers having less favorable chromatographic properties.

  3. 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

  4. Low level laser irradiation stimulates osteogenic phenotype of mesenchymal stem cells seeded on a three-dimensional biomatrix.

    PubMed

    Abramovitch-Gottlib, Liat; Gross, Talia; Naveh, Doron; Geresh, Shimona; Rosenwaks, Salman; Bar, Ilana; Vago, Razi

    2005-12-01

    Mesenchymal stem cells (MSCs) seeded on three-dimensional (3D) coralline (Porites lutea) biomatrices were irradiated with low-level laser irradiation (LLLI). The consequent phenotype modulation and development of MSCs towards ossified tissue was studied in this combined 3D biomatrix/LLLI system and in a control group, which was similarly grown, but was not treated by LLLI. The irradiated and non irradiated MSC were tested at 1-7, 10, 14, 21, 28 days of culturing via analysis of cellular distribution on matrices (trypan blue), calcium incorporation to newly formed tissue (alizarin red), bone nodule formation (von Kossa), fat aggregates formation (oil red O), alkaline phosphatase (ALP) activity, scanning electron microscopy (SEM) and electron dispersive spectrometry (EDS). The results obtained from the irradiated samples showed enhanced tissue formation, appearance of phosphorous peaks and calcium and phosphate incorporation to newly formed tissue. Moreover, in irradiated samples ALP activity was significantly enhanced in early stages and notably reduced in late stages of culturing. These findings of cell and tissue parameters up to 28 days of culture revealed higher ossification levels in irradiated samples compared with the control group. We suggest that both the surface properties of the 3D crystalline biomatrices and the LLLI have biostimulatory effects on the conversion of MSCs into bone-forming cells and on the induction of ex-vivo ossification.

  5. I- V and deep level transient spectroscopy studies on 60 MeV oxygen ion irradiated NPN transistors

    NASA Astrophysics Data System (ADS)

    Gnana Prakash, A. P.; Ke, S. C.; Siddappa, K.

    2004-02-01

    NPN transistors have been irradiated by 60 MeV oxygen ions in a fluence ranging from 5 × 10 10 to 1 × 10 13 ions/cm 2. The DC current gain ( hFE), excess base current ( ΔI B=I B post -I B pre ), excess collector current ( ΔI C=I C post -I C pre ) and collector saturation current (I C Sat ) of the ion irradiated transistors were studied systematically. The hFE of the transistors were found to be decreased drastically after ion irradiation. A significant increase has been observed in the collector current ( IC) along with the increase in the base current ( IB) after ion irradiation. The I C Sat of the ion irradiated transistors were also decreased significantly after irradiation. The radiation induced trap levels in the collector base depletion region of NPN transistors were studied by deep level transient spectroscopy technique and different types of trap levels were observed. The results obtained on the activation energy, density of trap levels, apparent capture cross section, introduction rate and space charge layer lifetime of different defects for different total fluence are presented and discussed.

  6. 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.

  7. 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.

  8. Reactive oxygen species levels and DNA fragmentation on astrocytes in primary culture after acute exposure to low intensity microwave electromagnetic field.

    PubMed

    Campisi, Agata; Gulino, Marisa; Acquaviva, Rosaria; Bellia, Paolo; Raciti, Giuseppina; Grasso, Rosaria; Musumeci, Francesco; Vanella, Angelo; Triglia, Antonio

    2010-03-31

    The exposure of primary rat neocortical astroglial cell cultures to acute electromagnetic fields (EMF) in the microwave range was studied. Differentiated astroglial cell cultures at 14 days in vitro were exposed for 5, 10, or 20min to either 900MHz continuous waves or 900MHz waves modulated in amplitude at 50Hz using a sinusoidal waveform and 100% modulation index. The strength of the electric field (rms value) at the sample position was 10V/m. No change in cellular viability evaluated by MTT test and lactate dehydrogenase release was observed. A significant increase in ROS levels and DNA fragmentation was found only after exposure of the astrocytes to modulated EMF for 20min. No evident effects were detected when shorter time intervals or continuous waves were used. The irradiation conditions allowed the exclusion of any possible thermal effect. Our data demonstrate, for the first time, that even acute exposure to low intensity EMF induces ROS production and DNA fragmentation in astrocytes in primary cultures, which also represent the principal target of modulated EMF. Our findings also suggest the hypothesis that the effects could be due to hyperstimulation of the glutamate receptors, which play a crucial role in acute and chronic brain damage. Furthermore, the results show the importance of the amplitude modulation in the interaction between EMF and neocortical astrocytes.

  9. 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.

  10. 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.

  11. Efficient Lewis acid ionic liquid-catalyzed synthesis of the key intermediate of coenzyme Q10 under microwave irradiation.

    PubMed

    Chen, Yue; Zu, Yuangang; Fu, Yujie; Zhang, Xuan; Yu, Ping; Sun, Guoyong; Efferth, Thomas

    2010-12-22

    An efficient synthesis of a valuable intermediate of coenzyme Q(10) by microwave-assisted Lewis acidic ionic liquid (IL)-catalyzed Friedel-Crafts alkylation is reported. The acidity of six [Etpy]BF(4)-based ionic liquids was characterized by means of the FT-IR technique using acetonitrile as a molecular probe. The catalytic activities of these ionic liquids were correlated with their Lewis acidity. With increasing Lewis acid strength of the ionic liquids, their catalytic activity in the Friedel-Crafts reaction increased, except for [Etpy]BF(4)-AlCl(3). The effects of the reaction system, the molar fraction of Lewis acid in the Lewis acid ILs and heating techniques were also investigated. Among the six Lewis acid ionic liquids tested [Etpy]BF(4)-ZnCl(2) showed the best catalytic activity, with a yield of 89% after a very short reaction time (150 seconds). This procedure has the advantages of higher efficiency, better reusability of ILs, energy conservation and eco-friendliness. The method has practical value for preparation of CoQ(10) on an industrial scale.

  12. 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.

  13. Computation of temperature elevation in rabbit eye irradiated by 2.45-GHz microwaves with different field configurations.

    PubMed

    Hirata, Akimasa; Watanabe, Soichi; Taki, Masao; Fujiwara, Osamu; Kojima, Masami; Sasaki, Kazuyuki

    2008-02-01

    This study calculated the temperature elevation in the rabbit eye caused by 2.45-GHz near-field exposure systems. First, we calculated specific absorption rate distributions in the eye for different antennas and then compared them with those observed in previous studies. Next, we re-examined the temperature elevation in the rabbit eye due to a horizontally-polarized dipole antenna with a C-shaped director, which was used in a previous study. For our computational results, we found that decisive factors of the SAR distribution in the rabbit eye were the polarization of the electromagnetic wave and antenna aperture. Next, we quantified the eye average specific absorption rate as 67 W kg(-1) for the dipole antenna with an input power density at the eye surface of 150 mW cm(-2), which was specified in the previous work as the minimum cataractogenic power density. The effect of administrating anesthesia on the temperature elevation was 30% or so in the above case. Additionally, the position where maximum temperature in the lens appears is discussed due to different 2.45-GHz microwave systems. That position was found to appear around the posterior of the lens regardless of the exposure condition, which indicates that the original temperature distribution in the eye was the dominant factor.

  14. [Experimental estimation of thermogenic levels of acute microwave exposure for different animal species].

    PubMed

    Kolganova, O I; Drozd, A I; Zhavoronkov, L P; Baranov, V D; Glushakova, V S; Panferova, T A

    2000-01-01

    In experiments on laboratory animals it was found the different patterns of reactions in response to acute thermogenic 7 GHz CW microwave exposures. The effects were related specifically to the intensity of the field. SAR equal 0.5-0.7 power of basal metabolism of different species did not result in increase of body temperature. At SARs over intensity of basal metabolism (up to 1.5-2.0 basal metabolism for the mice and for the rats and up to 1.5 for the rabbits) the "stepped" pattern of body heating with periods of rectal temperature stabilization was observed. This results may have implications for prognostic estimation of dose-temporal limits of endurable intensities of microwaves.

  15. 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.

  16. Modification of the repeated acquisition of response sequences in rats by low-level microwave exposure

    SciTech Connect

    Schrot, J.; Thomas, J.R.; Banvard, R.A.

    1980-01-01

    The acute effects of microwave exposure on a repeated acquisition baseline were investigated in three rats. Each session the animals acquired a different four-member response sequence. Each of the first three correct responses advanced the sequence to the next member, and the fourth correct response produced food reinforcement. Incorrect responses produced a three-second timeout. Baseline and control sessions were characterized by a decrease in errors within each session. The animals were acutely exposed to a 2.8 GHz pulsed-microwave field prior to test sessions, with average power densities ranging from 0.25 to to 10 mW/cm2. In comparison to control sessions, 1/2 hour of exposure to microwave radiation at power densities of 5 and 10 mW/cm2 increased errors and altered the pattern of within-session acquisition. Exposure to the 10 mW/cm2 power density decreased the rate of sequence completion in all animals. The results of exposures at 0.25, 0.5, and 1 mW/cm2 power densities were generally within the control range. The results are interpreted as indicating a disruption in the discriminative stimulus control of the repeated acquisition behavior.

  17. Degradation of surfactant wastewater under microwave irradiation in the presence of activated carbon assisted with nano-sized TiO2 or nano-sized ZnO.

    PubMed

    Zhang, Z; Xu, D; Shen, M; Wu, D; Chen, Z; Ji, X; Li, F; Xu, Y

    2011-01-01

    An improved method treating surfactant wastewater by the addition of semiconductor material such as nano-sized TiO2 or ZnO to activated carbon (AC) with microwave (MW) irradiation was proposed so as to assist efficient degradation of organic pollutants. A series of degradation experiments of sodium dodecyl benzene sulfonate (SDBS) were carried out under MW irradiation in the presence of AC/TiO2 or AC/ZnO. The influences of catalyst dose, irradiation time, initial SDBS concentration and solution acidity on the degradation were assessed in detail. The results showed that the addition of TiO2 or ZnO obviously promoted the degradation and AC/TiO2 system displayed higher catalytic activity under MW irradiation. Thus the method of MW irradiation with AC/TiO2 or AC/ZnO revealed many advantages of rapid degradation rate, short irradiation time, low cost, no residual intermediates and no secondary pollution in applications.

  18. Experimental and numerical determination of the correlation function of level velocities for microwave networks simulating quantum graphs

    NASA Astrophysics Data System (ADS)

    Ławniczak, Michał; Nicolau-Kuklińska, Agata; Hul, Oleh; Masiak, Paweł; Bauch, Szymon; Sirko, Leszek

    2013-03-01

    The parameter-dependent correlation function \\tilde {c}_{\\delta }(\\omega ,\\mathsf {x}) of level velocities is studied experimentally and numerically. The measurements were made for microwave networks simulating quantum graphs. One- and two-port measurements of the scattering matrix \\hat {S} necessary for determining the correlation function \\tilde {c}_{\\delta }(\\omega ,\\mathsf {x}) were realized for the five vertices networks. For the fully connected six vertices network, one-port measurements were made. The obtained experimental and numerical results are compared with the predictions of random matrix theory.

  19. 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.

  20. Cirrus cloud radiative forcing on surface-level shortwave and longwave irradiances at regional and global scale

    NASA Astrophysics Data System (ADS)

    Dupont, J. C.; Haeffelin, M.; Long, C. N.

    2009-04-01

    Cirrus clouds not only play a major role in the energy budget of the Earth-Atmosphere system, but are also important in the hydrological cycle. According to satellite passive remote sensing high-altitude clouds cover as much as 40% of the earth's surface on average and can reach 70% of cloud cover over the Tropics. Hence, given their very large cloud cover, the relatively small instantaneous radiative effects of these cirrus clouds can engender a significant cumulative radiative forcing at the surface. Precise calculations of the cirrus cloud radiative forcing are obtained from the difference between measured radiative fluxes downwelling at the surface in the presence of cirrus clouds (broadband flux measurements) and computed clear sky references (parametric models with RMS error < 5 W m-2). Overcast and clear sky period identification is obtained from a combined analysis of lidar and broadband flux measurements. In this study, we analyze two datasets: ground-based and satellite measurements. The firsts corresponds to solar and infrared irradiance measurements, cloud and aerosol Lidar backscattering profiles, microwave radiometer brightness temperatures, radiosonde profiles, and sun-photometer extinctions monitored at four observatories located in the midlatitudes (SIRTA Observatory and ARM SGP Lamont), the Tropics (ARM TWP Nauru) and the Arctic (ARM NSA Barrow). This dataset permits us to estimate the Cirrus cloud Radiative Forcing (cloud base altitude above 7 km) on surface-level shortwave (CRFSW) and longwave (CRFLW) irradiances. The sensitivity of CRFSW to Cloud Optical Thickness (noted CRFSW*) is established and ranges from 100 W m-2 to 200 W m-2 per unit of cloud optical thickness. The important variability of aerosols and water vapor content obtained in studying the 4 observatories allows us to quantify the combined influence of aerosol optical thickness and integrated water vapor on CRFSW* : 10 to 20 % CRFSW* range for turbid and pristine atmosphere

  1. Low-level laser therapy on bone repair: is there any effect outside the irradiated field?

    PubMed

    Batista, Jonas Dantas; Sargenti-Neto, Sérgio; Dechichi, Paula; Rocha, Flaviana Soares; Pagnoncelli, Rogério Miranda

    2015-07-01

    The biological effects of local therapy with laser on bone repair have been well demonstrated; however, this possible effect on bone repair outside the irradiated field has not been evaluated. The aim of this study was to investigate the effect of low-level laser therapy (LLLT) (λ = 830 nm) on repair of surgical bone defects outside the irradiated field, in rats. Sixty Wistar rats were submitted to osteotomy on the left femur and randomly separated into four groups (n = 15): group I, control, bone defect only; group II, laser applied on the right femur (distant dose); group III, laser applied locally on the bone defect and also on the right femur (local and distant doses); and group IV, laser applied locally on the left femur (local dose). Laser groups received applications within a 48-h interval in one point per session of density energy (DE) = 210 J/cm(2), P = 50 mW, t = 120 s, and beam diameter of 0.028 cm. Five animals of each group were euthanized 7, 15, and 21 days after surgery. Histologic analysis in all groups showed new bone formation in the region of interest (ROI) at 7 days. After 15 days, bone remodeling with a decrease of bone neoformation in the marrow area was observed in all groups. After 21 days, advanced bone remodeling with new bone mostly located in the cortical area was observed. The histomorphometric analysis showed at 7 days a significant increase of bone formation in groups III and IV compared to groups I and II. At days 15 and 21, histomorphometric analysis showed no significant differences between them. Laser therapy presented a positive local biostimulative effect in the early stage of bone healing, but the LLLT effect was not observed a long distance from the evaluated area.

  2. 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.

  3. Current resonances and current platforms in a two-level InAs quantum dot with asymmetric terahertz irradiations

    NASA Astrophysics Data System (ADS)

    Yuan, R.-Y.; Zhao, X.; Ji, A.-C.; Guo, Y.; Yan, H.

    2015-09-01

    Both the charging and orbital quantization energies of InAs quantum dot (QD) typically correspond to the terahertz (THz) region. In this letter, under the asymmetric THz irradiations on two leads, electron transport through a two-level InAs QD is theoretically discussed. We demonstrate that when both the frequencies and amplitudes of THz irradiations on two leads are different with the higher asymmetry, the photon-electron pump effect vanishes, even a negative platform appears on the left of the Coulomb peak and a positive platform occurs on the right of the Coulomb interaction related energy level, respectively. This behavior is favorable for the design of THz optoelectronic device.

  4. 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.

  5. Microwave sintering of ceramic materials

    NASA Astrophysics Data System (ADS)

    Karayannis, V. G.

    2016-11-01

    In the present study, the potential of microwave irradiation as an innovative energy- efficient alternative to conventional heating technologies in ceramic manufacturing is reviewed, addressing the advantages/disadvantages, while also commenting on future applications of possible commercial interest. Ceramic materials have been extensively studied and used due to several advantages they exhibit. Sintering ceramics using microwave radiation, a novel technology widely employed in various fields, can be an efficient, economic and environmentally-friendlier approach, to improve the consolidation efficiency and reduce the processing cycle-time, in order to attain substantial energy and cost savings. Microwave sintering provides efficient internal heating, as energy is supplied directly and penetrates the material. Since energy transfer occurs at a molecular level, heat is generated throughout the material, thus avoiding significant temperature gradients between the surface and the interior, which are frequently encountered at high heating rates upon conventional sintering. Thus, rapid, volumetric and uniform heating of various raw materials and secondary resources for ceramic production is possible, with limited grain coarsening, leading to accelerated densification, and uniform and fine-grained microstructures, with enhanced mechanical performance. This is particularly important for manufacturing large-size ceramic products of quality, and also for specialty ceramic materials such as bioceramics and electroceramics. Critical parameters for the process optimization, including the electromagnetic field distribution, microwave-material interaction, heat transfer mechanisms and material transformations, should be taken into consideration.

  6. 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.

  7. Bioactive compound loaded stable silver nanoparticle synthesis from microwave irradiated aqueous extracellular leaf extracts of Naringi crenulata and its wound healing activity in experimental rat model.

    PubMed

    Bhuvaneswari, T; Thiyagarajan, M; Geetha, N; Venkatachalam, P

    2014-07-01

    An efficient and eco-friendly protocol for the synthesis of bioactive silver nanoparticles was developed using Naringi crenulata leaf extracts via microwave irradiation method. Silver nanoparticles were synthesized by treating N. crenulata leaf extracts with 1mM of aqueous silver nitrate solution. An effective bioactive compound such as alkaloids, phenols, saponins and quinines present in the N. crenulata reduces the Ag(+) into Ag(0). The synthesized silver nanoparticles were monitored by UV-vis spectrophotometer and further characterized by X-ray diffraction (XRD), Fourier Transform Infra Red (FTIR), Energy-dispersive X-ray spectroscopy (EDX) and field emission scanning electron microscopy (FESEM). UV-vis spectroscopy showed maximum absorbance at 390nm due to surface plasmon resonance of AgNPs. From FESEM results, an average crystal size of the synthesized nanoparticle was 72-98nm. FT-IR results showed sharp absorption peaks and they were assigned to phosphine, alkyl halides and sulfonate groups. Silver nanoparticles synthesized were generally found to be spherical and cubic shape. Topical application of ointment prepared from silver nanoparticles of N. crenulata were formulated and evaluated in vivo using the excision wound healing model on Wistar albino rats. The measurement of the wound areas was performed on 3rd, 6th, 9th, 12th and 15th days and the percentage of wound closures was calculated accordingly. By the 15th day, the ointment base containing 5% (w/w) of silver nanoparticles showed 100% wound healing activity compared with that of the reference as well as control bases. The results strongly suggested that the batch C ointment containing silver nanaoparticles synthesized from the leaf extracts of N. crenulata was found to be very effective in wound repair and encourages harnessing the potentials of the plant biomolecules loaded silver nanoparticle in the treatment of tropical diseases including wound healing.

  8. 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.

  9. 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.

  10. 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.

  11. Irradiation creep and creep rupture of titanium-modified austenitic stainless steels and their dependence on cold work level

    SciTech Connect

    Garner, F.A.; Hamilton, M.L. ); Eiholzer, C.R. ); Toloczko, M.B. ); Kumar, A.S. )

    1991-11-01

    A titanium-modified austenitic type stainless steel was tested at three cold work levels to determine its creep and creep rupture properties under both thermal aging and neutron irradiation conditions. Both the thermal and irradiation creep behavior exhibit a complex non-monotonic relationship with cold work level that reflects the competition between a number of stress-sensitive and temperature-dependent microstructural processes. Increasing the degree of cold work to 30% from the conventional 20% level was detrimental to its performance, especially for applications above 550{degrees}c. The 20% cold work level is preferable to the 10% level, in terms of both in-reactor creep rupture response and initial strength.

  12. Influence of cold work level on the irradiation creep and creep rupture of titanium-modified austenitic stainless steels

    SciTech Connect

    Garner, F.A.; Hamilton, M.L. ); Eiholzer, C.R. ); Toloczko, M.B. ); Kumar, A.S. )

    1992-06-01

    A titanium-modified austenitic type stainless steel was tested at three cold work levels to determine its creep and creep rupture properties under both thermal aging and neutron irradiation conditions. Both the thermal and irradiation creep behavior exhibit a complex non-monotonic relationship with cold work level that reflects the competition between a number of stress-sensitive and temperature-dependent microstructural processes. Increasing the degree of cold work to 30% form the conventional 20% level was detrimental to its performance, especially for applications above 550{degrees}C. The 20% cold work level is preferable to the 10% level, in terms of both in- reactor creep rapture response and initial strength.

  13. 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%.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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 TM02 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%.

  15. Microwave-Assisted Olefin Metathesis

    NASA Astrophysics Data System (ADS)

    Nicks, François; Borguet, Yannick; Sauvage, Xavier; Bicchielli, Dario; Delfosse, Sébastien; Delaude, Lionel; Demonceau, Albert

    Since the first reports on the use of microwave irradiation to accelerate organic chemical transformations, a plethora of papers have been published in this field. In most examples, microwave heating has been shown to dramatically reduce reaction times, increase product yields, and enhance product purity by reducing unwanted side reactions compared to conventional heating methods. The present contribution aims at illustrating the advantages of this technology in olefin metathesis and, when data are available, at comparing microwave-heated and conventionally heated experiments

  16. 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...

  17. 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.

  18. An adaptive scale factor based MPPT algorithm for changing solar irradiation levels in outer space

    NASA Astrophysics Data System (ADS)

    Kwan, Trevor Hocksun; Wu, Xiaofeng

    2017-03-01

    Maximum power point tracking (MPPT) techniques are popularly used for maximizing the output of solar panels by continuously tracking the maximum power point (MPP) of their P-V curves, which depend both on the panel temperature and the input insolation. Various MPPT algorithms have been studied in literature, including perturb and observe (P&O), hill climbing, incremental conductance, fuzzy logic control and neural networks. This paper presents an algorithm which improves the MPP tracking performance by adaptively scaling the DC-DC converter duty cycle. The principle of the proposed algorithm is to detect the oscillation by checking the sign (ie. direction) of the duty cycle perturbation between the current and previous time steps. If there is a difference in the signs then it is clear an oscillation is present and the DC-DC converter duty cycle perturbation is subsequently scaled down by a constant factor. By repeating this process, the steady state oscillations become negligibly small which subsequently allows for a smooth steady state MPP response. To verify the proposed MPPT algorithm, a simulation involving irradiances levels that are typically encountered in outer space is conducted. Simulation and experimental results prove that the proposed algorithm is fast and stable in comparison to not only the conventional fixed step counterparts, but also to previous variable step size algorithms.

  19. 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.

  20. A Facile and Efficient Synthesis of Diaryl Amines or Ethers under Microwave Irradiation at Presence of KF/Al2O3 without Solvent and Their Anti-Fungal Biological Activities against Six Phytopathogens

    PubMed Central

    Huang, Liang-Zhu; Han, Pan; Li, You-Qiang; Xu, Ying-Meng; Zhang, Tao; Du, Zhen-Ting

    2013-01-01

    A series of diaryl amines, ethers and thioethers were synthesized under microwave irradiation efficiently at presence of KF/Al2O3 in 83%–96% yields without any solvent. The salient characters of this method lie in short reaction time, high yields, general applicability to substrates and simple workup procedure. At the same time, their antifungal biological activities against six phytopathogen were evaluated. Most of the compounds (3b, 3c, 3g–o) are more potent than thiophannate-methyl against to Magnaporthe oryzae. This implies that diaryl amine or ether moiety may be helpful in finding a fungicide against Magnaporthe oryzae. PMID:24036444

  1. Deep level transient spectroscopy study of particle irradiation induced defects in n-6H-SiC

    NASA Astrophysics Data System (ADS)

    Chen, X. D.; Gong, M.; Fung, S.; Beling, C. D.; Ling, C. C.

    2004-03-01

    Neutron and electron irradiation induced deep level defects in n-type 6H-SiC have been investigated using deep level transient spectroscopy (DLTS) combined with annealing experiments. Deep levels ED1, E1/E2, Ei, and Z1/Z2 were observed in n-type 6H-SiC material irradiated with neutron. Thermal annealing studies of these deep levels revealed that ED1 and Ei annealed at a temperature below 350^oC, Z1/Z2 levels annealed out at 900^oC, while the intensity of the E1/E2 peaks increased with annealing temperature, reached a maximum at about 500-750^oC, and finally annealed out at 1400^oC. Upon further annealing at 1600^oC, four deep levels labeled NE1 at EC-0.44eV, NE2 EC-0.53eV, NE3 EC-0.64eV, and NE4 EC-0.68eV are produced. Ionization energies of these levels are similar to E1/E2 and Z1/Z2 respectively, but their capture cross sections are different. Samples were irradiated with electrons with different energies ranging from 0.2MeV to 1.7MeV. No deep level was detected in samples irradiated with 0.2MeV electron and deep levels ED1, E1/E2, and Ei were induced with electron energy larger than 0.3MeV.

  2. Ground-level spectral distribution of solar direct-normal irradiance and marine aerosol attenuation coefficients at Reunion Island

    SciTech Connect

    Vaxelaire, P.; Leveau, J.; Baldy, S. ); Menguy, G. )

    1991-01-01

    The ground-level spectral distribution of direct solar irradiance at Reunion Island was measured for six bands covering the spectrum of solar radiation. The measurements, distributed over one year, were made under clear sky conditions with a pyrheliometer (Eppley, NIP) and six large pass-band flat filters. Good stability of spectral irradiances as a function of solar height allows us to propose approximate relationships which significantly characterize the irradiance into each spectral band. Measurements at Reunion vary significantly from data obtained with the same apparatus in a northern hemisphere continental area (Lyon). The determination of aerosol attenuation coefficients, for different spectral bands, allows the establish of a mean curve, for these coefficients as a function of wavelength, characteristic for marine aerosols.

  3. Deep level transient spectroscopy (DLTS) study of defects introduced in antimony doped Ge by 2 MeV proton irradiation

    NASA Astrophysics Data System (ADS)

    Nyamhere, C.; Das, A. G. M.; Auret, F. D.; Chawanda, A.; Pineda-Vargas, C. A.; Venter, A.

    2011-08-01

    Deep level transient spectroscopy (DLTS) and Laplace-DLTS have been used to investigate the defects created in Sb doped Ge after irradiation with 2 MeV protons having a fluence of 1×10 13 protons/cm 2. The results show that proton irradiation resulted in primary hole traps at E V +0.15 and E V +0.30 eV and electron traps at E C -0.38, E C -0.32, E C -0.31, E C -0.22, E C -0.20, E C -0.17, E C -0.15 and E C -0.04 eV. Defects observed in this study are compared with those introduced in similar samples after MeV electron irradiation reported earlier. E C -0.31, E C -0.17 and E C -0.04, and E V +0.15 eV were not observed previously in similar samples after high energy irradiation. Results from this study suggest that although similar defects are introduced by electron and proton irradiation, traps introduced by the latter are dose dependent.

  4. 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.

  5. Low energy electron irradiation induced deep level defects in 6H-SiC: the implication for the microstructure of the deep levels E1/E2.

    PubMed

    Chen, X D; Yang, C L; Gong, M; Ge, W K; Fung, S; Beling, C D; Wang, J N; Lui, M K; Ling, C C

    2004-03-26

    N-type 6H-SiC samples irradiated with electrons having energies of E(e)=0.2, 0.3, 0.5, and 1.7 were studied by deep level transient technique. No deep level was detected at below 0.2 MeV irradiation energy while for E(e)>/=0.3 MeV, deep levels ED1, E(1)/E(2), and E(i) appeared. By considering the minimum energy required to displace the C atom or the Si atom in the SiC lattice, it is concluded that generation of the deep levels E(1)/E(2), as well as ED1 and E(i), involves the displacement of the C atom in the SiC lattice.

  6. Low Energy Electron Irradiation Induced Deep Level Defects in 6H-SiC: The Implication for the Microstructure of the Deep Levels E1/E2

    NASA Astrophysics Data System (ADS)

    Chen, X. D.; Yang, C. L.; Gong, M.; Ge, W. K.; Fung, S.; Beling, C. D.; Wang, J. N.; Lui, M. K.; Ling, C. C.

    2004-03-01

    N-type 6H-SiC samples irradiated with electrons having energies of Ee=0.2, 0.3, 0.5, and 1.7 were studied by deep level transient technique. No deep level was detected at below 0.2MeV irradiation energy while for Ee≥0.3 MeV, deep levels ED1, E1/E2, and Ei appeared. By considering the minimum energy required to displace the C atom or the Si atom in the SiC lattice, it is concluded that generation of the deep levels E1/E2, as well as ED1 and Ei, involves the displacement of the C atom in the SiC lattice.

  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. 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.

  9. Assessing the impact of synchrotron X-ray irradiation on proteinaceous specimens at macro and molecular levels.

    PubMed

    Moini, Mehdi; Rollman, Christopher M; Bertrand, Loïc

    2014-10-07

    Synchrotron radiation (SR) has become a preferred technique for the analysis of a wide range of archeological samples, artwork, and museum specimens. While SR is called a nondestructive technique, its effect on proteinaceous specimens has not been fully investigated at the molecular level. To investigate the molecular level effects of synchrotron X-ray on proteinaceous specimens, we propose a methodology where four variables are considered: (1) type of specimen: samples ranging from amino acids to proteinaceous objects such as silk, wool, parchment, and rabbit skin glue were irradiated; (2) synchrotron X-ray energy; (3) beam intensity; (4) irradiation time. Irradiated specimens were examined for both macroscopic and molecular effects. At macroscopic levels, color change, brittleness, and solubility enhancement were observed for several samples within 100 s of irradiation. At molecular levels, the method allowed one to quantify significant amino acid modifications. Aspartic acid (Asp), wool, parchment, and rabbit skin glue showed a significant increase in Asp racemization upon increasing irradiation time with rabbit skin glue showing the greatest increase in d-Asp formation. In contrast, Asp in silk, pure cystine (dimer of cysteine), and asparagine (Asn) did not show signs of racemization at the irradiation times studied; however, the latter two compounds showed significant signs of decomposition. Parchment and rabbit skin glue exhibited racemization of Asp, as well as racemization of isoleucine (Ile) and phenylalanine (Phe) after 100 s of irradiation with a focused beam. Under the experimental conditions and sample type and dimensions used here, more change was observed for focused and low energy (8 keV) beams than unfocused or higher energy (22 keV) beams. These results allow quantification of the change induced at the molecular level on proteinaceous specimens by synchrotron X-ray radiation and help to define accurate thresholds to minimize the probability of

  10. 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).

  11. Microwave-Assisted Tissue Preparation for Rapid Fixation, Decalcification, Antigen Retrieval, Cryosectioning, and Immunostaining

    PubMed Central

    2016-01-01

    Microwave irradiation of tissue during fixation and subsequent histochemical staining procedures significantly reduces the time required for incubation in fixation and staining solutions. Minimizing the incubation time in fixative reduces disruption of tissue morphology, and reducing the incubation time in staining solution or antibody solution decreases nonspecific labeling. Reduction of incubation time in staining solution also decreases the level of background noise. Microwave-assisted tissue preparation is applicable for tissue fixation, decalcification of bone tissues, treatment of adipose tissues, antigen retrieval, and other special staining of tissues. Microwave-assisted tissue fixation and staining are useful tools for histological analyses. This review describes the protocols using microwave irradiation for several essential procedures in histochemical studies, and these techniques are applicable to other protocols for tissue fixation and immunostaining in the field of cell biology. PMID:27840640

  12. Levels of glutamate, aspartate, GABA, and taurine in different regions of the cerebellum after x-irradiation-induced neuronal loss

    SciTech Connect

    Rea, M.A.; McBride, W.J.; Rohde, B.H.

    1981-01-01

    The levels of glutamate (Glu), aspartate (Asp), gamma-amino-n-butyric acid (GABA), and taurine (Tau) were determined in the cortex, molecular layer, and deep nuclei of cerebella of adult rats exposed to X-irradiation at 12-15 days following birth (to prevent the acquisition of late-forming granule cells; 12-15x group) and 8-15 days following birth (to prevent the acquisition of granule and stellate cells; 8-15x group). Also, the levels of the four amino acids were measured in the crude synaptosomal fraction (P2) isolated from the whole cerebella of the control, 12-15x, and 8-15x groups. The level of Glu was significantly decreased by (1) 6-20% in the cerebellar cortex; (2) 15-20% in the molecular layer; and (3) 25-50% in the P2 fraction of the X-irradiated groups relative to control values. The content of Glu in the deep nuclei was not changed by X-irradiation treatment. Regional levels of Asp were unchanged by X-irradiation, while its level in P2 decreased by 15-30% after treatment. The levels of GABA and Tau in the molecular layer, deep nuclei, or P2 were not changed in the experimental groups. However, there was a 15% increase in the levels of GABA and Tau in the cerebellar cortex of the 8-15x group relative to control values. The data support the proposed role of glutamate as the excitatory transmitter released from the cerebellar granule cells but are inconclusive regarding a transmitter role for either Tau or GABA from cerebellar stellate cells.

  13. Levels of glutamate, aspartate, GABA, and taurine in different regions of the cerebellum after x-irradiation-induced neuronal loss

    SciTech Connect

    Rea, M.A.; McBride, W.J.; Rohde, B.H.

    1981-01-01

    The levels of glutamate (Glu), aspartate (Asp), gamma-amino-n-butyric acid (GABA), and taurine (Tau) were determined in the cortex, molecular layer, and deep nuclei of cerebella of adult rats exposed to x-irradiation at 12 to 15 days following birth (to prevent the acquisition of late-forming granule cells; 12 to 15x group) and 8 to 15 days following birth (to prevent the acquisition of granule and stellate cells; 8 to 15x group). Also, the levels of the four amino acids were measured in the crude synaptosomal fraction (P2) isolated from the whole cerebella of the control, 12 to 15x, and 8 to 15x groups. The level of Glu was significantly decreased by (1) 6 to 20% in the cerebellar cortex; (2) 15 to 20% in the molecular layer; and (3) 25 to 50% in the P2 fraction of the x-irradiated groups relative to control values. The content of Glu in the deep nuclei was not changed by x-irradiation treatment. Regional levels of Asp were unchanged by x-irradiation, while its level in P2 decreased by 15 to 30% after treatment. The levels of GABA and Tau in the molecular layer, deep nuclei, or P2 were not changed in the experimental groups. However, there was a 15% increase in the levels of GABA and Tau in the cerebellar cortex of the 8 to 15x group relative to control values. The data support the proposed role of glutamate as the excitatory transmitter released from the cerebellar granule cells but are inconclusive regarding a transmitter role for either Tau or GBA from cerebellar stellate cells.

  14. [Effect of anabolic preparation fenobolin on blood, reproductive system and hormone levels in blood serum of fractionally irradiated male rats].

    PubMed

    Vereshchako, G G; Gorokh, G A; Fedosenko, O L; Gun'kova, N V; Iakushev, D L; Konoplia, E F

    2011-01-01

    Influence of anabolic drug (phenobolin) injection at a dose of 2.5 mg/kg on some indexes of blood, reproductive system, the level of thyroid hormones, corticosterone and testosterone in blood serum of the male rats exposed to a fractional irradiation at the total dose of 2.0 Gy have been studied. A significant decrease in the quantity of leucocytes and lymphocytes after a fractional irradiation without and with phenobolin introduction was determined. Introduction of anabolic drug resulted in a significant drop of relative mass of testes and, particularly, epididymes, and also in a sharp decrease of the number of mature germ cells isolated from epididymes. A combined action of phenobolin and fractional irradiation (2.0 Gy) led to a significant reduction (3-5 times) in the quantity of mature germ cells in an epididymis. In some cases phenobolin influenced the level of testosterone in blood serum of the intact and irradiated animals. The anabolic steroid drug affects negatively the state of reproductive system of male rats.

  15. 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.

  16. Quantitative study of stress levels in AT and BT cut quartz crystal microbalances associated with surface laser irradiation

    NASA Astrophysics Data System (ADS)

    Goodman, L. H.; Bililign, E. S.; McCann, B. J.; Keller, B. W.; Stevens, K.; Kenny, S. G.; Krim, J.

    The frequency response of an AT cut Quartz Crystal Microbalance (QCM) to laser irradiation has been increasingly studied in recent years, as the combination of photons with materials on a QCM's electrodes enables fundamental studies of topics that span biophysics to photovoltaics. In order for such studies to advance, however, the impact of heating effects associated with laser irradiation of the QCM must be accounted for. Prior studies reached qualitative conclusions that laser irradiation induces stress QCM's arising from non-uniform thermal expansion, but did not quantitatively measure the degree of stress. Secondary effects such as surface film desorption and/or changes in temperature were also reported to be present. We report here a study of the frequency response of AT and BT cut QCM's to laser irradiation. AT and BT cut QCM's have similar response to mass adsorption, but opposite frequency response to stress levels, allowing the stress levels induced by the laser light to be quantitatively measured when the results are compared. Studies were performed in both vacuum and air, to control for the presence of adsorbed films. As expected, system designs that minimize temperature gradients result in less of an effect. Work supported by NSF DMR-1310456.

  17. Microwave ovens: mapping the electrical field distribution.

    PubMed

    Ng, K H

    1991-07-01

    Uniformity of electric field intensity of microwaves within the microwave oven cavity is necessary to ensure even load-heating, and is particularly important in pathology procedures where small volume irradiation is carried out. A simple and rapid method for mapping electric field distribution, using reversible thermographic paint, is described. Spatial heating patterns for various positions, and the effects of introducing dummy loads to modify heating distributions, have been obtained for a dedicated microwave processor, and comparison made with a domestic microwave oven.

  18. Low-level (gallium-aluminum-arsenide) laser irradiation of Par-C10 cells and acinar cells of rat parotid gland.

    PubMed

    Onizawa, Katsuhiro; Muramatsu, Takashi; Matsuki, Miwako; Ohta, Kazumasa; Matsuzaka, Kenichi; Oda, Yutaka; Shimono, Masaki

    2009-03-01

    We investigated cell response, including cell proliferation and expression of heat stress protein and bcl-2, to clarify the influence of low-level [gallium-aluminum-arsenide (Ga-Al-As) diode] laser irradiation on Par-C10 cells derived from the acinar cells of rat parotid glands. Furthermore, we also investigated amylase release and cell death from irradiation in acinar cells from rat parotid glands. The number of Par-C10 cells in the laser-irradiated groups was higher than that in the non-irradiated group at days 5 and 7, and the difference was statistically significant (P < 0.01). Greater expression of heat shock protein (HSP)25 and bcl-2 was seen on days 1 and 3 in the irradiated group. Assay of the released amylase showed no significant difference statistically between the irradiated group and the non-irradiated group. Trypan blue exclusion assay revealed that there was no difference in the ratio of dead to live cells between the irradiated and the non-irradiated groups. These results suggest that low-level laser irradiation promotes cell proliferation and expression of anti-apoptosis proteins in Par-C10 cells, but it does not significantly affect amylase secretion and does not induce rapid cell death in isolated acinar cells from rat parotid glands.

  19. 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.

  20. On the electronic properties of GaSb irradiated with reactor neutrons and its charge neutrality level

    SciTech Connect

    Boiko, V. M.; Brudnii, V. N.; Ermakov, V. S.; Kolin, N. G.; Korulin, A. V.

    2015-06-15

    The electronic properties and the limiting position of the Fermi level in p-GaSb crystals irradiated with full-spectrum reactor neutrons at up to a fluence of 8.6 × 10{sup 18} cm{sup −2} are studied. It is shown that the irradiation of GaSb with reactor neutrons results in an increase in the concentration of free holes to p{sub lim} = (5−6) × 10{sup 18} cm{sup −3} and in pinning of the Fermi level at the limiting position F{sub lim} close to E{sub V} + 0.02 eV at 300 K. The effect of the annealing of radiation defects in the temperature range 100–550°C is explored.

  1. Imaging the efficacy of UVC irradiation on superficial brain tumors and metastasis in live mice at the subcellular level.

    PubMed

    Momiyama, Masashi; Suetsugu, Atsushi; Kimura, Hiroaki; Kishimoto, Hiroyuki; Aki, Ryoichi; Yamada, Akimitsu; Sakurada, Harumi; Chishima, Takashi; Bouvet, Michael; Endo, Itaru; Hoffman, Robert M

    2013-02-01

    The effect of UVC irradiation was investigated on a model of brain cancer and a model of experimental brain metastasis. For the brain cancer model, brain cancer cells were injected stereotactically into the brain. For the brain metastasis model, lung cancer cells were injected intra-carotidally or stereotactically. The U87 human glioma cell line was used for the brain cancer model, and the Lewis lung carcinoma (LLC) was used for the experimental brain metastasis model. Both cancer cell types were labeled with GFP in the nucleus and RFP in the cytoplasm. A craniotomy open window was used to image single cancer cells in the brain. This double labeling of the cancer cells with GFP and RFP enabled apoptosis of single cells to be imaged at the subcellular level through the craniotomy open window. UVC irradiation, beamed through the craniotomy open window, induced apoptosis in the cancer cells. UVC irradiation was effective on LLC and significantly extended survival of the mice with experimental brain metastasis. In contrast, the U87 glioma was relatively resistant to UVC irradiation. The results of this study suggest the use of UVC for treatment of superficial brain cancer or metastasis.

  2. Thermoluminescence study of X-ray and UV irradiated natural calcite and analysis of its trap and recombination level.

    PubMed

    Kalita, J M; Wary, G

    2014-05-05

    Thermoluminescence (TL) of natural light-orange color calcite (CaCO3) mineral in micro-grain powder form was studied at room temperature X-ray and UV irradiation under various irradiation times. TL was recorded in linear heating rate (2 K/s) from room temperature (300 K) to 523 K. Trapping parameters such as activation energy, order of kinetics, frequency factor have been evaluated by Computerized Glow Curve Deconvolution technique. Three electron trap centers had been estimated at depth 0.70, 1.30 and 1.49 eV from the conduction band. Investigation of emission spectra recorded at various temperatures showed single recombination center at depth 2.74 eV from the conduction band. Due to thermally assisted tunneling of electron and subsequent center-to-center recombination, a distinct peak of lower activation energy (0.60 eV) was observed at relatively higher temperature (~360 K) for X-ray irradiated sample. In UV excitation, there was an indication of photo-transfer phenomenon, where low TL intensity might have been observed; but due to simultaneous excitation of electrons from valence band to the trap level, TL intensity was found to increase with UV irradiation time. The results obtained within temperature range 300-523 K were explained by considering a band diagram.

  3. System-Level Performance Evaluation of Microwave Fiber-Optic Links

    NASA Astrophysics Data System (ADS)

    Ackerman, Edward Irving

    Future generations of phased array radar systems as well as steerable communication antennas will require feed and distribution to many hundreds--possibly thousands --of solid-state MMIC radiating elements. In phased arrays operating at millimeter-wave frequencies, backplane interface and signal distribution methods will need to fulfill strict performance criteria. The metallic waveguides and coaxial cables currently used as phased array backplane interconnects will be unable to meet these stringent requirements. At millimeter-wave frequencies, where array backplane congestion is a major problem, distribution of the RF and digital control signals using optical fiber offers significant weight and crosstalk immunity advantages. To realize all the benefits of optical fiber signal distribution in a phased array, the single most critical development is the high-performance RF fiber-optic link. Some radar and communication systems, however, have such stringent transmit and/or receive performance goals which may not be easily met with conventional fiber-optic links. Fulfilling such difficult performance criteria requires prudent link architecture design. Before choosing a fiber-optic link design approach, it would benefit the phased array antenna system designer to possess a means of determining what RF performance could be expected. To do this, the designer needs a means of verifying that the mixing, modulation, and detection methods and the devices selected will result in a link with high -fidelity performance at the RF design frequencies. This work provides just such a design tool. In order to identify how best to leverage the advantages of optical fiber signal distribution in a microwave or millimeter-wave phased array, this thesis will investigate the optical link architectures that offer the maximum potential for achieving high-performance, low-profile array backplane interfaces. To assist the designer in the choice of signal mixing technique, modulation scheme, and

  4. 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.

  5. 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...

  6. 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

  7. 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.

  8. The co-evolution of microstructure features in self-ion irradiated HT9 at very high damage levels

    NASA Astrophysics Data System (ADS)

    Getto, E.; Vancoevering, G.; Was, G. S.

    2017-02-01

    Understanding the void swelling and phase evolution of reactor structural materials at very high damage levels is essential to maintaining safety and longevity of components in Gen IV fast reactors. A combination of ion irradiation and modeling was utilized to understand the microstructure evolution of ferritic-martensitic alloy HT9 at high dpa. Self-ion irradiation experiments were performed on alloy HT9 to determine the co-evolution of voids, dislocations and precipitates up to 650 dpa at 460 °C. Modeling of microstructure evolution was conducted using the modified Radiation Induced Microstructure Evolution (RIME) model, which utilizes a mean field rate theory approach with grouped cluster dynamics. Irradiations were performed with 5 MeV raster-scanned Fe2+ ions on samples pre-implanted with 10 atom parts per million He. The swelling, dislocation and precipitate evolution at very high dpa was determined using Analytical Electron Microscopy in Scanning Transmission Electron Microscopy (STEM) mode. Experimental results were then interpreted using the RIME model. A microstructure consisting only of dislocations and voids is insufficient to account for the swelling evolution observed experimentally at high damage levels in a complicated microstructure such as irradiated alloy HT9. G phase was found to have a minimal effect on either void or dislocation evolution. M2X played two roles; a variable biased sink for defects, and as a vehicle for removal of carbon from solution, thus promoting void growth. When accounting for all microstructure interactions, swelling at high damage levels is a dynamic process that continues to respond to other changes in the microstructure as long as they occur. effect of dislocations on voids, effect of precipitates on dislocations and voids and combined effect of dislocations and precipitates on voids. The overall approach will be to examine a simple system of voids and dislocations and then incorporate the more complex treatments of

  9. The apoptotic effect and the plausible mechanism of microwave radiation on rat myocardial cells.

    PubMed

    Zhu, Wenhe; Cui, Yan; Feng, Xianmin; Li, Yan; Zhang, Wei; Xu, Junjie; Wang, Huiyan; Lv, Shijie

    2016-08-01

    Microwaves may exert adverse biological effects on the cardiovascular system at the integrated system and cellular levels. However, the mechanism underlying such effects remains poorly understood. Here, we report a previously uncharacterized mechanism through which microwaves damage myocardial cells. Rats were treated with 2450 MHz microwave radiation at 50, 100, 150, or 200 mW/cm(2) for 6 min. Microwave treatment significantly enhanced the levels of various enzymes in serum. In addition, it increased the malondialdehyde content while decreasing the levels of antioxidative stress enzymes, activities of enzyme complexes I-IV, and ATP in myocardial tissues. Notably, irradiated myocardial cells exhibited structural damage and underwent apoptosis. Furthermore, Western blot analysis revealed significant changes in expression levels of proteins involved in oxidative stress regulation and apoptotic signaling pathways, indicating that microwave irradiation could induce myocardial cell apoptosis by interfering with oxidative stress and cardiac energy metabolism. Our findings provide useful insights into the mechanism of microwave-induced damage to the cardiovascular system.

  10. Microwave Ovens

    MedlinePlus

    ... Emitting Products Radiation-Emitting Products and Procedures Home, Business, and Entertainment Products Microwave ... for Consumers Laws, Regulations & Standards Industry Guidance Other Resources Description Microwave ...

  11. Thermal characteristics analysis of microwaves reactor for pyrolysis of used cooking oil

    NASA Astrophysics Data System (ADS)

    Anis, Samsudin; Shahadati, Laily; Sumbodo, Wirawan; Wahyudi

    2017-03-01

    The research is objected to develop microwave reactor for pyrolysis of used cooking oil. The effect of microwave power as well as addition of char as absorber towards its thermal characteristic were investigated. Domestic microwave was modified and used to test the thermal characteristic of used cooking oil in the terms of temperature evolution, heating rate, and thermal efficiency. The samples were examined under various microwave power of 347W, 399W, 572W and 642W for 25 minutes of irradiation time. The char loading was tested in the level of 0, 50, and 100 g. Microwave reactor consists of microwave unit with a maximum power of 642W, a ceramic reactor, and a condenser equipped with temperature measurement system was successfully developed. It was found that microwave power and addition of absorber significantly influenced the thermal characteristic of microwave reactor. Under investigated condition, the optimum result was obtained at microwave power of 642W and 100 g of char. The condition was able to provide temperature of 480°C, heating rate of 18.2°C/min and thermal efficiency of 53% that is suitable to pyrolyze used cooking oil.

  12. Microwave radiation absorption: behavioral effects.

    PubMed

    D'Andrea, J A

    1991-07-01

    The literature contains much evidence that absorption of microwave energy will lead to behavioral changes in man and laboratory animals. The changes include simple perturbations or outright stoppage of ongoing behavior. On one extreme, intense microwave absorption can result in seizures followed by death. On the other extreme, man and animals can hear microwave pulses at very low rates of absorption. Under certain conditions of exposure, animals will avoid microwaves, while under other conditions, they will actively work to obtain warmth produced by microwaves. Some research has shown behavioral effects during chronic exposure to low-level microwaves. The specific absorption rates that produce behavioral effects seem to depend on microwave frequency, but controversy exists over thresholds and mechanism of action. In all cases, however, the behavioral disruptions cease when chronic microwave exposure is terminated. Thermal changes in man and animals during microwave exposure appear to account for all reported behavioral effects.

  13. 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.

  14. Detection of low-level copper contamination in p-type silicon by means of microwave photoconductive decay measurements

    NASA Astrophysics Data System (ADS)

    Yli-Koski, M.; Palokangas, M.; Haarahiltunen, A.; Väinölä, H.; Storgårds, J.; Holmberg, H.; Sinkkonen, J.

    2002-12-01

    In order to achieve a better understanding of the behaviour of copper in p-type silicon, studies of the recombination of copper were carried out by the microwave photoconductive decay measurement method (μ PCD) using high-intensity bias light. It was observed that in the presence of small oxygen precipitates, high-intensity light could be used to activate precipitation of interstitial copper. It is suggested that high-intensity light changes the charge state of interstitial copper from positive to neutral, which enhances the precipitation. The precipitation follows Ham's kinetics and results in an increase in the recombination rate, which is detectable even with very low copper concentrations. This phenomenon can be used to detect low levels of copper contamination by the μ PCD method. In addition, it was observed that out-diffusion as well as in-diffusion of interstitial copper could be affected by an external corona charge. Thus, it is suggested that copper atoms do not form stable bonds at the Si-SiO2 interface after out-diffusion from bulk silicon.

  15. Effect of disodium cromoglycate (DSCG) and antihistamines on post-irradiation cerebral blood flow and plasma levels of histamine and neurotensin

    SciTech Connect

    Cockerham, L.G.; Pautler, E.L.; Carraway, R.E.; Cochrane, D.E.; Hampton, J.D.

    1988-01-01

    In an attempt to elucidate mechanisms underlying the irradiation-induced decrease in regional cerebral blood flow (rCBF) in primates, hippocampal and visual cortical blood flows of rhesus monkeys were measured by hydrogen clearance, before and after exposure to 100-Gy, whole-body, gamma irradiation. Systemic blood pressures were monitored simultaneously. Systemic arterial plasma histamine and neurotensin levels were determined preirradiation and postirradiation. Compared to control animals, the irradiated monkeys exhibited an abrupt decline in systemic blood pressure to 23% of the preirradiation level within 10-min postirradiation, falling to 12% by 60 min. A decrease in hippocampal blood flow to 32% of the preirradiation level was noted at 10-min postirradiation, followed by a slight recovery to 43% at 30 min and a decline to 23% by 60 min. The cortical blood flow for the same animals showed a steady decrease to 29% of the preirradiation levels by 60-min postirradiation. Animals given the mast-cell stabilizer disodium cromoglycate and the antihistamines mepyramine and cimetidine before irradiation did not exhibit an abrupt decline in blood pressure but displayed a gradual decrease to a level 33% below preirradiation levels by 60 min postirradiation. Also, the treated, irradiated monkeys displayed rCBF values that were not significantly different from the nonirradiated controls. The plasma neurotensin levels in the irradiated animals, treated and untreated, indicated a nonsignificant postirradiation increase above control levels.

  16. 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.

  17. Observed instantaneous cirrus radiative effect on surface-level shortwave and longwave irradiances

    NASA Astrophysics Data System (ADS)

    Dupont, Jean-Charles; Haeffelin, Martial

    2008-11-01

    Data collected at the SIRTA Observatory, 20 km south of Paris, are analyzed to determine the instantaneous surface cloud radiative effect (CRE) induced by cirrus clouds. CRE is here defined as the difference between overcast-sky and clear-sky surface radiative fluxes obtained by ground-based measurement of broadband fluxes and clear-sky parametric models, respectively. Clear-sky periods detected by a double threshold based on lidar and radiative fluxes analysis show a root mean square error for clear-sky models smaller than 6.5 W m-2 for shortwave flux and 4 W m-2 for longwave flux. Over 100 h in 2003-2006 characterized by homogeneous overcast cirrus clouds are analyzed. Fifty percent of this cirrus population is subvisible and semitransparent, that is, with optical thickness less than 0.3. The mean surface shortwave cirrus cloud radiative effect (CRESW) is found near -50 W m-2. We establish the relationship between CRESW and cirrus optical thickness (COT) to be about -90 W m-2 per unit of COT. This SW sensitivity ranges from -80 W m-2 COT-1 to -100 W m-2 COT-1 for turbid to pristine atmospheres, respectively. We also establish the relationship between surface longwave cloud radiative effect (CRELW) and the irradiance emitted by the cirrus cloud derived from cloud infrared emissivity and cloud temperature. The average surface CRELW is about +5 W m-2. CRELW is found to be about 10% of the cloud irradiance. This LW effect ranges from 5 to 15% of the cirrus irradiance depending on atmospheric humidity for the wet and dry atmosphere, respectively.

  18. Determination of some traces metal levels in cheese samples packaged in plastic and tin containers by ICP-OES after dry, wet and microwave digestion.

    PubMed

    Bakircioglu, Dilek; Kurtulus, Yasemin Bakircioglu; Ucar, Gokhan

    2011-01-01

    The concentrations of Cd, Co, Cr, Cu, Mn, Ni, Pb, Se and Zn in cheese samples packaged in plastic and tin containers were analyzed using inductively coupled plasma-optical emission spectrometry after microwave, wet and dry digestion processes. In order to evaluate the best digestion method, the relationships between the concentrations of trace metals in cheese samples after microwave digestion was compared by wet and dry ashings. Microwave digestion was found fast, reliable, simple, and excellent procedure in comparison with dry and wet ashing methods. The accuracy of the digestion procedures was determined by using standard reference material (GBW 07605-Tea). The order of levels of the elements in the white cheese samples packaged in tin containers was determined to be Cdmicrowave digestion and cream cheese samples in plastic containers Cd

  19. 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.

  20. 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.

  1. 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)

  2. A green one-pot three-component synthesis of spirooxindoles under conventional heating conditions or microwave irradiation by using Fe3O4@SiO2-imid-PMAn magnetic porous nanospheres as a recyclable catalyst

    NASA Astrophysics Data System (ADS)

    Esmaeilpour, Mohsen; Javidi, Jaber; Divar, Masoumeh

    2017-02-01

    An efficient, green and environmentally procedure for the synthesis of spirooxindole derivatives has been developed by a one-pot three-component reaction of isatin derivatives, activated methylene, and 1,3-dicarbonyl compounds in the presence of Fe3O4@SiO2-imid-PMAn magnetic nanocatalyst under conventional heating conditions in water or microwave irradiation under solvent-free conditions. The reactions under conventional heating conditions were compared with the microwave-assisted reactions. The suggested method offers several advantages such as excellent yields, short reaction times, operational simplicity, a cleaner reaction, absence of any tedious workup or purification and ease of recovery and reusability of the catalyst by a magnetic field. In addition, the excellent catalytic performance in a water medium and the easy preparation, thermal stability and separation of the catalyst make it a good heterogeneous system and a useful alternative to other heterogeneous catalysts. The catalyst can be easily recovered by a magnetic field and reused for six consecutive reaction cycles without significant loss of activity. Also, the morphology of Fe3O4@SiO2-imid-PMAn, particle size distribution and leaching of nano H3PMo12O40 (PMAn) after reaction cycles were investigated by scanning electron microscopy (SEM), dynamic light scattering (DLS), and inductively coupled plasma (ICP) analyzer.

  3. 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

    2016-08-05

    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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Microwave assisted extraction of pectin from waste Citrullus lanatus fruit rinds.

    PubMed

    Prakash Maran, J; Sivakumar, V; Thirugnanasambandham, K; Sridhar, R

    2014-01-30

    In this present study, microwave-assisted extraction (MAE) was applied to extraction of pectin from waste Citrullus Lanatus fruit rinds. Extraction parameters which are employed in this study are microwave power (160-480 W), irradiation time (60-180s), pH (1-2) and solid-liquid ratio (1:10-1: 30 g/ml) and they were optimized using a four factor three levels Box-Behnken response surface design (BBD) coupled with desirability function methodology. The results showed that, all the process variables have significant effect on the extraction yield of pectin. Optimum MAE conditions for the highest pectin yield from waste C. Lanatus fruit rinds (25.79%) were obtained with microwave power of 477 W, irradiation time of 128 s, pH of 1.52, solid-liquid ratio of 1:20.3g/ml respectively. Validation experiment results were well agreed with predicted value.

  11. Photodegradation of crystal violet in TiO(2) suspensions using UV-vis irradiation from two microwave-powered electrodeless discharge lamps (EDL(-2)): products, mechanism and feasibility.

    PubMed

    Ju, Yongming; Fang, Jiande; Liu, Xiaowen; Xu, Zhencheng; Ren, Xiuwen; Sun, Cheng; Yang, Shaogui; Ren, Qian; Ding, Youchao; Yu, Kai; Wang, Lianhong; Wei, Zhongbo

    2011-01-30

    Aqueous crystal violet (CV) solutions containing P25-TiO(2) photocatalyst were irradiated with ultraviolet-visible (UV-vis) light from two microwave-powered electrodeless discharge lamps (EDL(-2)). The results demonstrated that approximately 94.4% of CV was effectively removed after 3 min of irradiation, with a pseudo-first order kinetic constant of 0.838 min(-1). According to 32 kinds of products, a five-step degradation pathway of CV was proposed. Further investigations showed that (1) three kinds of N-demethylated products and 4-dimethylaminobenzophenone (DLBP) were the main intermediates; (2) malachite green (MG) and leuco-crystal violet could not be generated by N-demethylation and phototransformation reactions, respectively; (3) bis(4-(dimethylamino)phenyl)methanone preferentially generated via decomposition of the conjugated structure of CV could be further N-demethylated into DLBP. Moreover, the unique degradation pathways of CV and MG were ascribed to the different substituents on the conjugated structures. Additionally, the cost and kinetic constant of different processes was also evaluated, and the results indicated the feasibility of this method for treatment of CV in field situations.

  12. 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.

  13. Determination of the mineral fraction and rheological properties of microwave modified starch from Canna edulis.

    PubMed

    Lares, Mary; Pérez, Elevina

    2006-09-01

    The goal of this study was to evaluate the effect of the physical modification by microwave irradiation on the mineral fraction and rheological properties of starch isolated from Canna edulis rhizomes. Phosphorus, sodium, potassium, magnesium, iron, calcium and zinc were evaluated using atomic absorption spectrophotometry. Rheological properties were determined using both the Brabender amylograph and Brookfield viscosimeter. Except for the calcium concentration, mineral contents decreased significantly (p < 0.05) after microwave treatment. The amylographic profile was also modified, showing increased pasting temperature range and breakdown index, whereas the viscosity peak, viscosity at holding (95 degrees C) and cooling periods (50 degrees C), setback and consistency decreased as compared to the native starch counterpart. Although viscosity decreased in the microwaved sample, presumably due to starch changes at molecular level, it retained the general pseudo plastic behavior of native starch. It is concluded that canna starch may be modified by microwave irradiation in order to change its functional properties. This information should be considered when using microwave irradiation for food processing. Furthermore, the altered functional attributes of canna modified starch could be advantageous in new product development.

  14. Microwave-assisted technology for the clearing and staining of arbuscular mycorrhizal fungi in roots.

    PubMed

    Dalpé, Yolande; Séguin, Sylvie Marie

    2013-05-01

    The use of microwave irradiation as a source of energy to clear and stain intra-radical arbuscular mycorrhizal fungi propagules has been tested on a variety of indigenous and cultivated herbaceous plants. The aim of the study was to evaluate the efficiency of microwave irradiation on root softening, fungi tissue staining, and preservation of DNA integrity for subsequent molecular analyses. The proposed methodology has been adapted from the standard procedures used to detect and quantify mycorrhizal root colonization levels. Using a domestic microwave oven, tissue clearing and staining required together between 30 s and 1.5 min of microwave treatment to be completed, depending the diameter size of the roots. The well-performing chemical stains tested were acid fuchsin, trypan blue, and aniline blue. The acid fuchsin clearing and staining processes, as performed, were also demonstrated to preserve DNA integrity for further molecular analyses. Irradiation by microwaves has been used with success in our laboratory within the frame of several studies. It offers considerable time saving over traditional method, reducing processing times from several hours to a few minutes while decreasing considerably the amount of chemicals and energy required to perform analyses.

  15. 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.

  16. 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.

  17. Effect of microwave radiation on inactivation of Clostridium sporogenes (PA 3679) spores

    SciTech Connect

    Welt, B.A.; Lund, D.B.; Rossen, J.L. ); Tong, C.H. Rutgers Univ., Cook College, New Brunswick, NJ )

    1994-02-01

    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. Rats 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 form 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.

  18. 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

  19. Microwave assisted synthesis & properties of nano HA-TCP biphasic calcium phosphate

    NASA Astrophysics Data System (ADS)

    Ghomash Pasand, E.; Nemati, A.; Solati-Hashjin, M.; Arzani, K.; Farzadi, A.

    2012-05-01

    Biphasic calcium phosphate (BCP) nanopowders were synthesized by using microwave and non-microwave irradiation assisted processes. The synthesized powders were pressed under a pressure of 90 MPa, and then were sintered at 1000-1200°C for 1 h. The mechanical properties of the samples were investigated. The formed phases and microstructures were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the synthesis time was shorter, along with a more homogeneous microstructure, when the microwave irradiation assisted method was applied. The compression strength and the Young's modulus of the samples synthesized with microwave irradiation were about 60 MPa and 3 GPa, but those of the samples synthesized without microwave irradiation were about 30 MPa and 2 GPa, respectively. XRD patterns of the microwave irradiation assisted and non-microwave irradiation assisted nanopowders showed the coexistence of hydroxyapatite (HA) and tricalcium phosphate (TCP) phases in the system.

  20. 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.

  1. A constitutive damage specific DNA-binding protein is synthesized at higher levels in UV-irradiated primate cells

    SciTech Connect

    Hirschfeld, S.; Levine, A.S.; Ozato, K.; Protic, M. )

    1990-05-01

    Using a DNA band shift assay, we have identified a DNA-binding protein complex in primate cells which is present constitutively and has a high affinity for UV-irradiated, double-stranded DNA. Cells pretreated with UV light, mitomycin C, or aphidicolin have higher levels of this damage-specific DNA-binding protein complex, suggesting that the signal for induction can either be damage to the DNA or interference with cellular DNA replication. Physiochemical modifications of the DNA and competition analysis with defined substrates suggest that the most probable target site for the damage-specific DNA-binding protein complex is a 6-4'-(pyrimidine-2'-one)-pyrimidine dimer: specific binding could not be detected with probes which contain -TT- cyclobutane dimers, and damage-specific DNA binding did not decrease after photoreactivation of UV-irradiated DNA. This damage-specific DNA-binding protein complex is the first such inducible protein complex identified in primate cells. Cells from patients with the sun-sensitive cancer-prone disease, xeroderma pigmentosum (group E), are lacking both the constitutive and the induced damage-specific DNA-binding activities. These findings suggest a possible role for this DNA-binding protein complex in lesion recognition and DNA repair of UV-light-induced photoproducts.

  2. Influence of the copper impurity level on the irradiation response of reactor pressure vessel steels investigated by SANS

    NASA Astrophysics Data System (ADS)

    Wagner, Arne; Ulbricht, Andreas; Bergner, Frank; Altstadt, Eberhard

    2012-06-01

    Reactor pressure vessel (RPV) steel, when exposed to neutron irradiation, induces the formation of nano-sized features. Using small angle neutron scattering (SANS) we have studied the neutron fluence dependence of the precipitate volume fraction for high-Cu and low-Cu materials separately. Cu-rich precipitates have long been recognized to play the dominant role in embrittlement of Cu-bearing RPV steels. In contrast, Mn-Ni-rich precipitates seem to govern embrittlement in the case of low levels of impurity Cu. The objective is to work out the resulting differences from the microstructural point of view. For low-Cu materials, the volume fraction was found to be within the detection limit of SANS at fluences below an apparent threshold fluence, whereas the slope increases considerably beyond. The relationship between irradiation-induced yield stress increase and precipitate volume fraction was also considered. We have derived estimates of the obstacle strength for Cu-rich precipitates and for Mn-Ni-rich precipitates.

  3. 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.

  4. Deep level transient spectroscopic study of neutron-irradiated n-type 6H-SiC

    NASA Astrophysics Data System (ADS)

    Chen, X. D.; Fung, S.; Ling, C. C.; Beling, C. D.; Gong, M.

    2003-09-01

    Deep level transient spectroscopy has been employed to study the deep level defects introduced in n-type 6H-SiC after neutron irradiation. Deep levels situated at EC-0.23, EC-0.36/0.44, EC-0.50, and EC-0.62/0.68 eV have been detected in the temperature range of 100-450 K, which have been identified with the previously reported deep levels ED1, E1/E2, Ei, and Z1/Z2, respectively. Thermal annealing studies of these deep levels reveal that ED1 and Ei anneal at a temperature below 350 °C, the Z1/Z2 levels anneal out at 900 °C, while the intensity of the E1/E2 peaks is increased with annealing temperature, reaching a maximum at about 500-750 °C, and finally annealing out at 1400 °C. The possible nature of the deep levels ED1, E1/E2, Ei, and Z1/Z2 are discussed in the context of their annealing behavior. Upon further annealing at 1600 °C, four deep levels labeled NE1 at EC-0.44 eV, NE2 EC-0.53 eV, NE3EC-0.64 eV, and NE4EC-0.68 eV are produced. Evidence is given that these levels are different in their origin to E1/E2 and Z1/Z2.

  5. 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.

  6. A framework for predicting the yield stress, Charpy toughness and one hundred-year activation level for irradiated fusion power plant alloys

    NASA Astrophysics Data System (ADS)

    Windsor, Colin; Cottrell, Geoff; Kemp, Richard

    2011-04-01

    Recent papers have demonstrated that the yield stress and the Charpy ductile to brittle transition temperature shift at the high irradiation levels of a fusion power plant may be predicted from measurements at lower irradiation levels using neural networks. It was demonstrated that the extrapolation inherent in such predictions could be validated provided that network complexity was appropriately low. Simultaneous predictions of these metallurgical properties at the 100 dpa irradiation level and 400 °C irradiation temperature of a possible fusion power plant have been made for a series of ferritic/martensitic steels, albeit based on mainly fission data. Together with the readily available one hundred-year activation level, benefit functions are defined which can be used to predict the most suitable alloys for a fusion power plant from within existing databases. Our model is sufficiently flexible to allow a variety of possible benefit functions to be defined. The F82H, Eurofer and LA12 alloy series all receive a favourable rating, although all results presented here must be tempered with caution until more data at relevant irradiation levels and with relevant energy spectra become available.

  7. [The state of the mitochondrial energy-supplying system of blood leukocytes in the dynamics of Guerin's carcinoma growth under the low-level irradiation conditions].

    PubMed

    Marchenko, M M; Voloshchuk, O N

    2014-01-01

    Mitochondrial NADH-dehydrogenase, succinate dehydrogenase and cytochrome oxidase activities of peripheral blood leukocytes of rats with the grafted Guerin's carcinoma were studied in the dynamics of oncogenesis under the conditions of the preliminary low-level irradiation. Tumor growth was accompanied by a decrease in NADH-dehydrogenase activity, an increase of succinate dehydrogenase activity. Cytochrome oxidase activity of leucocytes remained at the control level up to the terminal stages of tumor growth. Preliminary low-level irradiation of the tumor bearing animals caused a tendency to the decrease of enzymatic activities studied. This tendency was observed from the initial stages of oncogenesis.

  8. A study of the double-acceptor level of the silicon divacancy in a proton irradiated n-channel CCD

    NASA Astrophysics Data System (ADS)

    Wood, D.; Hall, D.; Gow, J. P. D.; Holland, A.

    2016-08-01

    Radiation damage effects are problematic for space-based detectors. Highly energetic particles, predominantly from the sun can damage a detector and reduce its operational lifetime. For an image sensor such as a Charge-Coupled Device (CCD) impinging particles can potentially displace silicon atoms from the CCD lattice, creating defects which can trap signal charge and degrade an image through smearing. This paper presents a study of one energy level of the silicon divacancy defect using the technique of single trap-pumping on a proton irradiated n-channel CCD. The technique allows for the study of individual defects at a sub-pixel level, providing highly accurate data on defect parameters. Of particular importance when concerned with CCD performance is the emission time-constant of a defect level, which is the time-scale for which it can trap a signal charge. The trap-pumping technique is a direct probe of individual defect emission time-constants in a CCD, allowing for them to be studied with greater precision than possible with other defect analysis techniques such as deep-level transient spectroscopy on representative materials.

  9. Deep Level Defects in Electron-Irradiated Aluminum Gallium Nitride Grown by Molecular Beam Epitaxy

    DTIC Science & Technology

    2005-03-01

    To date, these energy levels have not been systematically measured (i.e. temperature dependent Hall ( TDH ) and deep level transient spectroscopy...Material I.D. Ref. Donors 0.06 0.018 0.06 0.06 e- (1 MeV) TDH undoped HVPE n≈1017 VN SiGa 33 Acceptors deep e- (1 MeV) TDH " NI 33...qualitative agreement with the linear carrier removal model of equation II-33. More recently, TDH measurements were reported for the same type of GaN sample

  10. Accelerated esterification of free fatty acid using pulsed microwaves.

    PubMed

    Kim, Daeho; Choi, Jinju; Kim, Geun-Ju; Seol, Seung Kwon; Jung, Sunshin

    2011-07-01

    It was demonstrated that pulsed microwave irradiation is a more effective method to accelerate the esterification of free fatty acid with a heterogeneous catalyst than continuous microwave irradiation. A square-pulsed microwave with a 400 Hz repetition rate and a 10-20% duty cycle with the same energy as the continuous microwave were used in this study. The pulsed microwaves improved the esterification conversion from 39.9% to 66.1% after 15 min in comparison with the continuous microwave under the same reaction conditions. These results indicated that pulsed microwaves with repetitive strong power could enhance the efficiency of biodiesel production relative to the use of continuous microwave with mild power.

  11. Increased cell proliferation and differential protein expression induced by low-level Er:YAG laser irradiation in human gingival fibroblasts: proteomic analysis.

    PubMed

    Ogita, Mayumi; Tsuchida, Sachio; Aoki, Akira; Satoh, Mamoru; Kado, Sayaka; Sawabe, Masanori; Nanbara, Hiromi; Kobayashi, Hiroaki; Takeuchi, Yasuo; Mizutani, Koji; Sasaki, Yoshiyuki; Nomura, Fumio; Izumi, Yuichi

    2015-09-01

    Erbium-doped yttrium aluminum garnet (Er:YAG) laser treatment has demonstrated favorable wound healing effect after periodontal therapy. One of the reasons may be the positive biological effect of the low-level laser on the irradiated tissues, although the mechanism remains unclear. The aim of this study was to investigate the effect of low-level Er:YAG laser irradiation on cell proliferation and laser-induced differential expression of proteins in human gingival fibroblasts (HGFs) by proteomic analysis. In the first experiment, HGFs were exposed to low-level Er:YAG laser irradiation and the laser-induced cell proliferation and damage were evaluated on day 3. In the second experiment, proteomic analysis was performed on day 1 after irradiation. The peptides prepared from HGFs were analyzed by a hybrid ion trap-Fourier transform mass spectrometer, Mascot search engine, and UniProtKB database. A significant increase in cell proliferation without cell damage after irradiation was observed. Among the total identified 377 proteins, 59 proteins, including galectin-7, which was associated with the process of wound healing, were upregulated and 15 proteins were downregulated in laser-treated HGFs. In the third experiment, the increase in messenger RNA (mRNA) and protein expression of galectin-7 in the irradiated HGFs was validated by various analytical techniques. In addition, the effect of recombinant human galectin-7 on the modulation of HGFs proliferation was confirmed. The results indicate that low-level Er:YAG laser irradiation can promote HGF proliferation and induce a significant change in protein expression and the upregulation of galectin-7 expression may partly contribute to the increase in cell proliferation.

  12. The effects of irradiance levels and spectral composition on mating strategies in the snow alga, Chloromonas sp.-D, from the Tughill Plateau, New York State

    NASA Astrophysics Data System (ADS)

    Hoham, Ronald W.; Schlag, Erin M.; Kang, Jennifer Y.; Hasselwander, Andrew J.; Behrstock, Alissa F.; Blackburn, Ian R.; Johnson, Rurik C.; Roemer, Stephen C.

    1998-07-01

    Studies have related changes in snow albedo to snow crystal structure and to the presence of surface debris (i.e. pine needles), but there has been less attention given to the existence of algae in snow. An increase in the number of snow algae could also decrease albedo and increase snowmelt rates. The primary purpose of this paper is to document how solar irradiance serves to control the developing stages of algae in snow. Snow algae do not appear near the surface until there is meltwater in the snowpack. Low levels of solar irradiance penetrate through the snowpack and germinate snow algal resting stages that lie underneath, and snow algal growth is enhanced by available gases and nutrients. Flagellate cells swim through the snowpack in the meltwater around the snow crystals, and cells are positioned according to irradiance and spectral differences. In this study, Chloromonas sp.-D strains 582C and 582D, isolated from the upper 20 cm of snowpacks in the Tughill Plateau, Whetstone Gulf State Park, NY, were used to investigate mating strategies under different irradiance levels and spectral compositions in the laboratory, and the irradiance levels used in the experiments correlated with those recorded from the upper 20 cm of snow. Using similar irradiance levels, blue light regimes produced more matings than green and red light regimes. There were no trends in mating when comparing green and red light regimes. When red light regimes of higher photon irradiance (85 mol m-2 s-1) were compared with those of blue light regimes of lower irradiance (30 mol m-2 s-1), more mating occurred under red light. A photon irradiance of 95 mol m-2 s-1 [photosynthetically active radiation (PAR) of 400-700 nm] produced the most mating under both wide-spectrum (WS) and cool-white (CW) regimes, but more mating occurred under CW in all irradiances tested. Mating pairs of three types were observed: oblong-oblong (o-o), oblong-sphere (o-s) and sphere-sphere (s-s). Cell packs that produced

  13. 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.

  14. 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.

  15. 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.

  16. Observation of the variations of the domain structure of a spontaneous electric field in a two-dimensional electron system under microwave irradiation

    NASA Astrophysics Data System (ADS)

    Dorozhkin, S. I.; Umansky, V.; von Klitzing, K.; Smet, J. H.

    2016-11-01

    It has been found on a sample of the GaAs/AlGaAs heterostructure with the two-dimensional electron system that different configurations of domains of a spontaneous electric field are possible within one microwave- induced state with the resistance tending to zero. Transitions between such configurations are observed at the variation of the radiation power and magnetic field. In the general case, the configuration of domains is more complicated than existing models. The fragment of the distribution of the electric field in the sample for one of the observed configurations is in agreement with the rhombic domain structure considered by I. G. Finkler and B. I. Halperin, Phys. Rev. B 79, 085315 (2009).

  17. 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.

  18. ATR-SEIRAS investigation of the Fermi level of Pt cocatalyst on a GaN photocatalyst for hydrogen evolution under irradiation.

    PubMed

    Yoshida, Masaaki; Yamakata, Akira; Takanabe, Kazuhiro; Kubota, Jun; Osawa, Masatoshi; Domen, Kazunari

    2009-09-23

    The interaction of photogenerated carries in GaN photocatalyst with Pt cocatalyst for hydrogen evolution under irradiation was investigated from in situ ATR-SEIRAS measurement by following the CO vibrational frequency. After irradiation, the CO frequency shifted higher, indicating that the Fermi level of Pt particles was positively shifted by the photogenerated holes. Thereafter, a lower frequency peak appeared, indicating that the Fermi level of some Pt particles was negatively shifted to the hydrogen evolution potential by photogenerated electrons, which is the essential function of cocatalysis for hydrogen evolution.

  19. Low-level laser irradiation promotes the proliferation and maturation of keratinocytes during epithelial wound repair

    PubMed Central

    Sperandio, Felipe F.; Simões, Alyne; Corrêa, Luciana; Aranha, Ana Cecília C.; Giudice, Fernanda S.; Hamblin, Michael R.; Sousa, Suzana C.O.M.

    2015-01-01

    Low-level laser therapy (LLLT) has been extensively employed to improve epithelial wound healing, though the exact response of epithelium maturation and stratification after LLLT is unknown. Thus, this study aimed to assess the in vitro growth and differentiation of keratinocytes (KCs) and in vivo wound healing response when treated with LLLT. Human KCs (HaCaT cells) showed an enhanced proliferation with all the employed laser energy densities (3, 6 and 12 J/cm2, 660nm, 100mW), together with an increased expression of Cyclin D1. Moreover, the immunoexpression of proteins related to epithelial proliferation and maturation (p63, CK10, CK14) all indicated a faster maturation of the migrating KCs in the LLLT-treated wounds. In that way, an improved epithelial healing was promoted by LLLT with the employed parameters; this improvement was confirmed by changes in the expression of several proteins related to epithelial proliferation and maturation. PMID:25411997

  20. Microwave Supported Treatment of Sewage Sludge

    NASA Astrophysics Data System (ADS)

    Janíček, František; Perný, Milan; Šály, Vladimír; Giemza, Markus; Hofmann, Peter

    2016-07-01

    This work is focused on microwave treatment of sewage sludge. The aim of our experiments was to investigate the impact of microwave radiation upon different sewage sludge parameters such as concentration of nitrates and nitrites, phosphates, COD (Chemical Oxygen Demand), SVI (Sludge Volume Index) and the microscopic structure of sludge. The experiments with microwave irradiation of sewage sludge indicate that moderate microwave power causes visible effects on the chemical, physical and biological properties of the sludge. The calculation of profitability and energy efficiency is also presented.

  1. 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.

  2. Delayed reproductive consequences of low-level irradiation early in life

    SciTech Connect

    Dobson, R.L.

    1985-11-01

    The possibility that significant, heretofore overlooked biological effects may follow low-level radiation exposure during the vulnerable developmental stages early in life led to examine such exposures in mice and monkeys. The initial concern was with tritium, so animals were exposed to tritiated water. Gamma rays were also used, and served as a standard for comparison; special studies were done with neutrons. Thus, three radiations of particular importance to nuclear energy were involved. In measuring effects, focus was on female germ cells (oocytes) because they: (a) are crucial for species survival, (b) are confined to the ovary and can be counted, and (c) constitute a cell population that in mammals is established early-definitive numbers are present before birth and new oocytes cannot be formed thereafter. Thus, in contrast to cells of renewal systems, including male germ cells, where losses can be made up by multiplication of precursors, oocytes when killed are irreplaceable. The results of the authors experiments are discussed and interpreted with respect to implications for man.

  3. Effect of low-level laser therapy on irradiated parotid glands--study in mice.

    PubMed

    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.

  4. Microwave irradiation for the facile synthesis of transition-metal nanoparticles (NPs) in ionic liquids (ILs) from metal-carbonyl precursors and Ru-, Rh-, and Ir-NP/IL dispersions as biphasic liquid-liquid hydrogenation nanocatalysts for cyclohexene.

    PubMed

    Vollmer, Christian; Redel, Engelbert; Abu-Shandi, Khalid; Thomann, Ralf; Manyar, Haresh; Hardacre, Christopher; Janiak, Christoph

    2010-03-22

    Stable chromium, molybdenum, tungsten, manganese, rhenium, ruthenium, osmium, cobalt, rhodium, and iridium metal nanoparticles (M-NPs) have been reproducibly obtained by facile, rapid (3 min), and energy-saving 10 W microwave irradiation (MWI) under an argon atmosphere from their metal-carbonyl precursors [M(x)(CO)(y)] in the ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF(4)]). This MWI synthesis is compared to UV-photolytic (1000 W, 15 min) or conventional thermal decomposition (180-250 degrees C, 6-12 h) of [M(x)(CO)(y)] in ILs. The MWI-obtained nanoparticles have a very small (<5 nm) and uniform size and are prepared without any additional stabilizers or capping molecules as long-term stable M-NP/IL dispersions (characterization by transmission electron microscopy (TEM), transmission electron diffraction (TED), and dynamic light scattering (DLS)). The ruthenium, rhodium, or iridium nanoparticle/IL dispersions are highly active and easily recyclable catalysts for the biphasic liquid-liquid hydrogenation of cyclohexene to cyclohexane with activities of up to 522 (mol product) (mol Ru)(-1) h(-1) and 884 (mol product) (mol Rh)(-1) h(-1) and give almost quantitative conversion within 2 h at 10 bar H(2) and 90 degrees C. Catalyst poisoning experiments with CS(2) (0.05 equiv per Ru) suggest a heterogeneous surface catalysis of Ru-NPs.

  5. 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.

  6. 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 Central

    Azzam, Edouard I.; Ferraris, Ronaldo P.; Howell, Roger W.

    2015-01-01

    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

  7. 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.

  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 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.

  10. 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

  11. Two methods for microwave irradiation synthesis of TiO2–ZnO–graphene ternary hybrids with enhanced photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Darvishi, Motahareh; Jamali-Paghaleh, Mina; Jamali-Paghaleh, Fatemeh; Seyed-Yazdi, Jamileh

    2017-01-01

    In this study, graphene–zinc oxide–titanium dioxide (RGO–ZnO–TiO2) ternary hybrids are successfully synthesized by two methods called ‘one step’ and ‘two steps’, by using a simple microwave treatment of a solution containing graphene oxide, ZnO, TiO2, water and ethanol. Their morphology, structure, and photocatalytic performance in degradation of methylene blue, were characterized by scanning electron microscopy, energy dispersive x-ray analysis, x-ray diffraction analysis, Fourier transform infrared and UV–vis analysis. The results show that RGO–ZnO–TiO2 (GZT) hybrids (containing 7% graphene mass ratio) improve photodegradation efficiency 1.39- and 1.8-fold, compared with RGO–ZnO (GZT0) (containing 7% graphene mass ratio) and pure ZnO, because of reduction of electron–hole recombination in ZnO due to introduction of TiO2. Furthermore, we found that the photocatalytic activity in the ‘one step’ method is higher than in ‘two steps’.

  12. 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.

  13. 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.

  14. Rapid synthesis, characterization and optical properties of TiO{sub 2} coated ZnO nanocomposite particles by a novel microwave irradiation method

    SciTech Connect

    Bahadur, Newaz Mohammed; Furusawa, Takeshi; Sato, Masahide; Kurayama, Fumio; Suzuki, Noboru

    2010-10-15

    A novel and rapid microwave method was used to prepare TiO{sub 2} coated ZnO nanocomposite particles. The resulted particles were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Results show that ZnO nanoparticles were coated with 6-10 nm amorphous TiO{sub 2} layers. In addition, zeta potential analysis demonstrated the presence of TiO{sub 2} layer on the surface of ZnO nanoparticles. Photoluminescence (PL) spectroscopy and UV-visible spectroscopy were used to investigate the optical properties of the nanoparticles. Compared to uncoated ZnO nanoparticles, the TiO{sub 2} coated ZnO nanoparticles showed enhanced UV emission. The UV-visible diffuse reflectance study revealed the significant UV shielding characteristics of the nanocomposite particles. Moreover, amorphous TiO{sub 2} coating effectively reduced the photocatalytic activity of ZnO nanoparticles as evidenced by the photodegradation of Orange G with uncoated and TiO{sub 2} coated ZnO nanoparticles under UV radiation.

  15. 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.

  16. 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.

  17. Pain and mobility improvement and MDA plasma levels in degenerative osteoarthritis, low back pain, and rheumatoid arthritis after infrared A-irradiation.

    PubMed

    Siems, Werner; Bresgen, Nikolaus; Brenke, Rainer; Siems, Renate; Kitzing, Manfred; Harting, Heike; Eckl, Peter M

    2010-01-01

    Infrared (IR)-A irradiation can be useful in back and musculoskeletal pain therapy. In this study joint and vertebral column pain and mobility were measured during two weeks of IR-A irradiation treatment of patients suffering from degenerative osteoarthritis of hip and knee, low back pain, or rheumatoid arthritis. Additionally, before and after IR-A treatment MDA serum levels were measured to check if MDA variations accompany changes in pain intensity and mobility. Two-hundred and seven patients were divided into verum groups getting IR-irradiation, placebo groups getting visible, but not IR irradiation, and groups getting no irradiation. In osteoarthritis significant pain reduction according to Visual Analogue Scale and mobility improvements occurred in the verum group. Even though beneficial mean value changes occurred in the placebo group, the improvements in the placebo and No Irradiation groups were without statistical significance. In low back pain, pain and mobility improvements (by 35-40%) in the verum group were found, too. A delayed (2nd week) mobility improvement in rheumatoid arthritis was seen. However, pain relief was seen immediately. In patients suffering from low back pain or rheumatoid arthritis, the pain and mobility improvements were accompanied by significant changes of MDA serum levels. However, MDA appears not a sensitive biofactor for changes of the pain intensity in degenerative osteoarthritis. Nevertheless, unaffected or lowered MDA levels during intensive IR-A therapy argue against previous reports on free radical formation upon infrared. In conclusion, rapid beneficial effects of IR-A towards musculoskeletal pain and joint mobility loss were demonstrated.

  18. 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.

  19. 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.

  20. Deep level transient spectroscopy study of electron traps in n-type GaAs after pulsed electron beam irradiation

    SciTech Connect

    Marrakchi, G.; Barbier, D.; Guillot, G.; Nouailhat, A.

    1987-10-01

    Electrical and deep level transient spectroscopy measurements on Schottky barriers were performed in order to characterize electrically active defects in n-type GaAs (Bridgman substrates or liquid-phase epitaxial layers) after pulsed electron beam annealing. Both surface damage and bulk defects were observed in the Bridgman substrates depending on the pulse energy density. No electron traps were detected in the liquid-phase epitaxial layers before and after annealing for an energy density of 0.4 J/cm/sup 2/. The existence of an interfacial insulating layer at the metal-semiconductor interface, associated with As out-diffusion during the pulsed electron irradiation, was revealed by the abnormally high values of the Schottky barrier diffusion potential. Moreover, two new electron traps with activation energy of 0.35 and 0.43 eV, called EP1 and EP2, were introduced in the Bridgman substrates after pulsed electron beam annealing. The presence of these traps, related to the As evaporation, was tentatively attributed to the decrease of the EL2 electron trap signal after 0.4-J/cm/sup 2/ annealing. It is proposed that these new defects states are due to the decomposition of the As/sub Ga/-As/sub i/ complex recently considered as the most probable defect configuration for the dominant EL2 electron trap usually detected in as-grown GaAs substrates.

  1. Microwave-Assisted Rapid Enzymatic Synthesis of Nucleic Acids.

    PubMed

    Hari Das, Rakha; Ahirwar, Rajesh; Kumar, Saroj; Nahar, Pradip

    2016-07-02

    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.

  2. Microwave effects on plasmid DNA.

    PubMed

    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. 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.

  4. 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

  5. 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.

  6. 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.

  7. Microwaves and cellular immunity. II. Immunostimulating effects of microwaves and naturally occurring antioxidant nutrients.

    PubMed

    Novoselova, E G; Fesenko, E E; Makar, V R; Sadovnikov, V B

    1999-10-01

    The effect of 8.15-18 GHz (1 Hz within) microwave radiation at a power density of 1 microW/cm2 on the tumor necrosis factor (TNF) production and immune response was tested. A single 5 h whole-body exposure induced a significant increase in TNF production in peritoneal macrophages and splenic T cells. The mitogenic response in T lymphocytes increased after microwave exposure. The activation of cellular immunity was observed within 3 days after exposure. The diet containing lipid-soluble nutrients (beta-carotene, alpha-tocopherol and ubiquinone Q9) increased the activity of macrophages and T cells from irradiated mice. These results demonstrate that irradiation with low-power density microwaves stimulates the immune potential of macrophages and T cells, and the antioxidant treatment enhances the effect of microwaves, in particular at later terms, when the effect of irradiation is reduced.

  8. Comparison of sea-level measurements between microwave radar and subsurface pressure gauge deployed at select locations along the coast of India

    NASA Astrophysics Data System (ADS)

    Mehra, Prakash; Prabhudesai, Ramachandra Gopal; Joseph, Antony; Kumar, Vijay; Agarvadekar, Yogesh; Luis, Ryan; Nadaf, Lalsab

    2013-01-01

    Sea-level data are obtained from several remote and coastal locations using absolute pressure gauges deployed at known level, known as chart datum. However, to yield correct sea-level measurements from absolute pressure measurements, it is necessary to take into account the atmospheric pressure and water density at the measurement locations. We used data collected from microwave radar and an absolute pressure gauge deployed at Verem, Goa (January 2009 to May 2010), Tuticorin, and Mandapam, Tamil Nadu (June 2010 to March 2011) to carry out comparative studies. The root-mean-square difference between the estimated sea level from radar and pressure gauge (incorporating atmospheric pressure correction) is ˜2.69, 2.73, and 1.46 cm at Verem, Tuticorin, and Mandapam, respectively. Harmonic analysis of the two time-series of sea-level data at Verem produces similar residuals and tidal constituents. Our results indicate the importance of concurrent measurement of atmospheric pressure along with subsurface absolute pressure gauge measurements. Internet-based real-/near-real-time tracking and monitoring of sea level, sea state, and surface-meteorological conditions from a network of several island and coastal stations provides considerable information to disaster managers and local administrators during episodic events such as storms, storm surges, and tsunamis.

  9. Effect of chronic microwave radiation on T cell-mediated immunity in the rabbit

    NASA Astrophysics Data System (ADS)

    Nageswari, K. Sri; Sarma, K. R.; Rajvanshi, V. S.; Sharan, R.; Sharma, Manju; Barathwal, Vinita; Singh, Vinod

    1991-06-01

    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 anechoicchambers. 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<0.01, Δ% 21.5%) and during follow-up ( P<0.01, Δ% 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 (Δ 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 (Δ%+12.4 vs.+7.54). The animals were sacrified and the tissue T lymphocyte counts (spleen and lymph node) were analysed. No significant variation was observed in the tissue T lymphocyte counts of microwave-irradiated rabbits. From these results it is speculated that the T lymphocytes are sequestered to various lymphoid organs under the influence of microwaves. A sub-population of T cells known as T helper cells (mediating DTH response) are

  10. Microwave-assisted enzyme-catalyzed reactions in various solvent systems.

    PubMed

    Lin, Shan-Shan; Wu, Chi-Hong; Sun, Mei-Chuan; Sun, Chung-Ming; Ho, Yen-Peng

    2005-04-01

    The work describes the accelerated enzymatic digestion of several proteins in various solvent systems under microwave irradiation. The tryptic fragments of the proteins were analyzed by matrix-assisted laser desorption/ionization mass spectrometry. Under the influence of rapid microwave heating, these enzymatic reactions can proceed in a solvent such as chloroform, which, under traditional digestion conditions, renders the enzyme inactive. The digestion efficiencies and sequence coverages were increased when the trypsin digestions occurred in acetonitrile-, methanol- and chloroform-containing solutions that were heated under microwave irradiation for 10 min using a commercial microwave applicator. The percentage of the protein digested under microwave irradiation increased with the relative acetonitrile content, but decreased as the methanol content was increased. These observations suggest that acetonitrile does not deactivate the enzyme during the irradiation period; in contrast, methanol does deactivate it. In all cases, the digestion efficiencies under microwave irradiation exceed those under conventional conditions.

  11. 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.

  12. Microwave detector

    SciTech Connect

    Meldner, H.W.; Cusson, R.Y.; Johnson, R.M.

    1986-12-02

    A detector is described for measuring the envelope shape of a microwave pulse comprised of high-frequency oscillations, the detector comprising: a B-dot loop linking the magnetic field of the microwave pulse; a biased ferrite, that produces a magnetization field flux that links the B-dot loop. The ferrite is positioned within the B-dot loop so that the magnetic field of the microwave pulse interacts with the ferrite and thereby participates in the formation of the magnetization field flux; and high-frequency insensitive means for measuring electric voltage or current induced in the B-dot loop.

  13. Tolerance to high irradiance levels as a determinant of the bloom-forming Heterosigma akashiwo success in estuarine waters in summer

    NASA Astrophysics Data System (ADS)

    Butrón, Ainhize; Madariaga, Iosu; Orive, Emma

    2012-07-01

    The effect of irradiance, temperature and salinity was studied on the growth rates of two strains of the bloom-forming Heterosigma akashiwo isolated from the Nervión-Ibaizabal estuary (Bay of Biscay). Growth rates (μ) were measured at varying conditions of salinity (5-35), irradiance (90-1200 μE m-2 s-1), temperature (10-25 °C) and photoperiod (10L:14D-14L:10D). The response to these factors was compared with the observed distribution of the algae in the estuary. Irradiance was the factor that induced more variations on H. akashiwo growth rates, showing a positive correlation with the presence and abundance of the algae in the estuary. At irradiances higher than 350 μE m-2 s-1H. akashiwo adjusted the concentration of its photoprotective pigments (mainly violaxanthin). In addition, these strains are able to grow at irradiances as high as 1200 μE m-2 s-1 without experiencing photoinhibition. H. akashiwo also seems to be efficient at low irradiances as it was deduced from Ic values (˜90 μE m-2 s-1). This response is in agreement with the summer H. akashiwo presence in the estuary. Highest temperature would affect positively cell survival at low, suboptimal salinities (5, 10). However, there was no correlation between temperature and H. akashiwo presence. H. akashiwo bloomed at salinities 30-35 in protected areas of the Nervión-Ibaizabal estuary, while culture salinity optima was found between 20 and 25. Thus, during summer, salinity would be a growing determinant for H. akashiwo only at suboptimum levels and other factors would be responsible for blooms at salinities 30 and 35. Photoperiod would not to have any significant effect on its growth rates.

  14. Comparison of low-level polycyclic aromatic hydrocarbons in sediment revealed by Soxhlet extraction, microwave-assisted extraction, and pressurized liquid extraction.

    PubMed

    Itoh, Nobuyasu; Numata, Masahiko; Aoyagi, Yoshie; Yarita, Takashi

    2008-03-31

    We analyzed polycyclic aromatic hydrocarbons (PAHs) present in lake sediment at low levels (<1 microg g(-1)) by using Soxhlet extraction (Soxhlet), microwave-assisted extraction (MAE), and pressurized liquid extraction (PLE) in combination with gas chromatography and isotope-dilution mass spectrometry. Although all extraction techniques showed good repeatability for five target PAHs (relative standard deviation <5.2%, n=3), the results decreased in the order PLE>MAE>Soxhlet. Differences in the results originated mainly from differences in the extraction efficiencies of the techniques for native PAHs, because all techniques gave comparable recovery yields of corresponding 13C-labeled PAHs (13C-PAHs) (51-84%). Since non-negligible amounts of both native PAHs and 13C-PAHs were re-adsorbed on matrix in MAE, not only recovery yields of 13C-PAHs but also efficiencies of extraction of native PAHs should be examined to evaluate the appropriateness of any analytical procedures.

  15. 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

  16. Carbon-ion beams induce production of an immune mediator protein, high mobility group box 1, at levels comparable with X-ray irradiation.

    PubMed

    Yoshimoto, Yuya; Oike, Takahiro; Okonogi, Noriyuki; Suzuki, Yoshiyuki; Ando, Ken; Sato, Hiro; Noda, Shin-ei; Isono, Mayu; Mimura, Kousaku; Kono, Koji; Nakano, Takashi

    2015-05-01

    X-ray radiotherapy activates tumor antigen-specific T-cell responses, and increases in the serum levels of high mobility group box 1 (HMGB1) induced by X-ray irradiation play a pivotal role in activating anti-tumor immunity. Here, we examined whether carbon-ion beams, as well as X-rays, can induce HMGB1 release from human cancer cell lines. The study examined five human cancer cell lines: TE2, KYSE70, A549, NCI-H460 and WiDr. The proportion of cells surviving X- or carbon-ion beam irradiation was assessed in a clonogenic assay. The D10, the dose at which 10% of cells survive, was calculated using a linear-quadratic model. HMGB1 levels in the culture supernatants were assessed by an ELISA. The D10 dose for X-rays in TE2, KYSE70, A549, NCI-H460 and WiDr cells was 2.1, 6.7, 8.0, 4.8 and 7.1 Gy, respectively, whereas that for carbon-ion beams was 0.9, 2.5, 2.7, 1.8 and 3.5 Gy, respectively. X-rays and carbon-ion beams significantly increased HMGB1 levels in the culture supernatants of A549, NCI-H460 and WiDr cells at 72 h post-irradiation with a D10 dose. Furthermore, irradiation with X-rays or carbon-ion beams significantly increased HMGB1 levels in the culture supernatants of all five cell lines at 96 h post-irradiation. There was no significant difference in the amount of HMGB1 induced by X-rays and carbon-ion beams at any time-point (except at 96 h for NCI-H460 cells); thus we conclude that comparable levels of HMGB1 were detected after irradiation with iso-survival doses of X-rays and carbon-ion beams.

  17. 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.

  18. Microwave generator

    DOEpatents

    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.

  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. Alteration of spermatozoal structure and trace metal profile of testis and epididymis of rat under chronic low-level X-ray irradiation.

    PubMed

    Chatterjee, J; De, K; Basu, S K; Das, A K

    1994-06-01

    This study investigates the short-term as well as long-term effects of low-level X-ray irradiation on the Spermatozoal structure and trace metal (Zn, Fe, Cu, and Cd) contents in the testis and epididymis of whole-body irradiated albino rats. Male rats were exposed to 0.675, 1.350, 2.700, and 4.050 cGy of X-ray intermittently in 45, 90, 180, and 270 equal fractions (each fraction of 0.015 cGy s-1), respectively. SEM study had revealed numerous fusiform swelling in sperm tail in most of the x-irradiated groups. Moreover, in 2.700 and 4.050 cGy dose groups, the tail sheath of several sperm were eroded out. In the TEM study, damage in microtubules of sperm tail in 4.050 cGy irradiated group was noted. The AAS study showed a transient increase in Zn content in 0.675 and 1.350 cGy dose groups, but its concentration was decreased in 2.700 and 4.050 cGy dose groups. Fe concentration was increased in all the cases in comparison to that of control group. Nevertheless, Cu and Cd contents were increased mostly in 2.700 and 4.050 cGy doses. Thus present findings probably throw some light regarding mammalian response threshold at low-level X-ray irradiation. Moreover, it raises questions regarding the validity of "safe dose ionizing radiation."

  1. 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...

  2. 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

  3. Microwave-Induced Chemotoxicity of Polydopamine-Coated Magnetic Nanocubes.

    PubMed

    Julfakyan, Khachatur; Fatieiev, Yevhen; Alsaiari, Shahad; Deng, Lin; Ezzeddine, Alaa; Zhang, Dingyuan; Rotello, Vincent M; Khashab, Niveen M

    2015-08-06

    Polydopamine-coated FeCo nanocubes (PDFCs) were successfully synthesized and tested under microwave irradiation of 2.45 GHz frequency and 0.86 W/cm(2) 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.

  4. 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....

  5. 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...

  6. Effect of low-level laser therapy irradiation and Bio-Oss graft material on the osteogenesis process in rabbit calvarium defects: a double blind experimental study.

    PubMed

    Rasouli Ghahroudi, Amir Alireza; Rokn, Amir Reza; Kalhori, Katayoun A M; Khorsand, Afshin; Pournabi, Alireza; Pinheiro, A L B; Fekrazad, Reza

    2014-05-01

    This study aims to assess the effect of low-level laser therapy (LLLT) irradiation and Bio-Oss graft material on the osteogenesis process in the rabbit calvarium defects. Twelve white male New Zealand rabbits were included in this study. Four 8-mm diameter identical defects were prepared on each rabbit's calvarium. One site was left as an untreated control (C), the second site was filled with Bio-Oss (B), the third site was treated with laser irradiation (L), and the fourth site treated with Bio-Oss and laser irradiation (B + L). In the laser group, a diode laser (wavelength 810 nm, output power 300 mW, irradiation mode CW, energy density 4 J/cm2) was applied immediately after surgery and then one other day for the next 20 days. After 4 and 8 weeks, the animals were sacrificed and histological and histomorphometric examinations were performed and the data were subjected to Friedman and repeated measurements ANOVA tests. Significant differences were not found regarding inflammation severity, foreign body reactions, and vitality of newly formed bone on 4th and 8th week after operation. The mean amount of new bone was 15.83 and 18.5% in the controls on the 4th and 8th week; 27.66 and 25.16% in the laser-irradiated group; 35.0 and 41.83% in Bio-Oss and 41.83 and 47.0% in the laser + Bio-Oss treated specimens with significant statistical differences (p <0.05). Application of LLLT in combination with Bio-Oss® can promote bone healing. Therefore, LLLT may be clinically beneficial in promoting bone formation in skeletal defects.

  7. Large-area irradiated low-level laser effect in a biodegradable nerve guide conduit on neural regeneration of peripheral nerve injury in rats.

    PubMed

    Shen, Chiung-Chyi; Yang, Yi-Chin; Liu, Bai-Shuan

    2011-08-01

    This study used a biodegradable composite containing genipin-cross-linked gelatin annexed with β-tricalcium phosphate ceramic particles (genipin-gelatin-tricalcium phosphate, GGT), developed in a previous study, as a nerve guide conduit. The aim of this study was to analyse the influence of a large-area irradiated aluminium-gallium-indium phosphide (AlGaInP) diode laser (660 nm) on the neural regeneration of the transected sciatic nerve after bridging the GGT nerve guide conduit in rats. The animals were divided into two groups: group 1 comprised sham-irradiated controls and group 2 rats underwent low-level laser (LLL) therapy. A compact multi-cluster laser system with 20 AlGaInP laser diodes (output power, 50mW) was applied transcutaneously to the injured peripheral nerve immediately after closing the wound, which was repeated daily for 5 min for 21 consecutive days. Eight weeks after implantation, walking track analysis showed a significantly higher sciatic function index (SFI) score (P<0.05) and better toe spreading development in the laser-treated group than in the sham-irradiated control group. For electrophysiological measurement, both the mean peak amplitude and nerve conduction velocity of compound muscle action potentials (CMAPs) were higher in the laser-treated group than in the sham-irradiated group. The two groups were found to be significantly different during the experimental period (P<0.005). Histomorphometric assessments revealed that the qualitative observation and quantitative analysis of the regenerated nerve tissue in the laser-treated group were superior to those of the sham-irradiated group. Thus, the motor functional, electrophysiologic and histomorphometric assessments demonstrate that LLL therapy can accelerate neural repair of the corresponding transected peripheral nerve after bridging the GGT nerve guide conduit in rats.

  8. 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.

  9. Microwave coupling in EBT reactor

    SciTech Connect

    Uckan, N.A.; Uckan, T.; Dandl, R.A.

    1980-02-01

    For a typical size ELMO Bumpy Torus (EBT) reactor (approx. 1000 MWe), microwave frequencies required lie in the range of 60 to 110 GHz at power levels of 50 to 75 MW. As the frequency rises, the unloaded cavity (i.e., without plasma) quality factor Q decreases. Because of the short wavelengths of microwave heating power and the large cavity dimensions of a reactor, it is possible to apply quasi-optical principles in the efficient coupling of power to the plasma. The use of a confocal Fabry-Perot resonator with spherical mirrors is discussed; these serve to confine the microwave power to the region occupied by the plasma. The potential advantages of these resonators include high efficiency utilization of microwave power, minimal thermal burden on the cryopumping system, and significant benefit in preventing microwave leakage from the device. An estimation of the unloaded cavity quality factor Q and the design considerations of Fabry-Perot resonator are given.

  10. 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.

  11. 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.

  12. 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 }.

  13. Microwave-induced hearing: some preliminary theoretical observations.

    PubMed

    Lin, J C

    1976-09-01

    Pulsed microwaves impinging on the head of animals and man produce auditory sensations. Theoretical analyses indicate a series of resonant frequencies occurring inside the head. This is supported by previous observations of characteristic oscillations recorded from the round window of mammals during pulsed microwave irradiation.

  14. 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...

  15. 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...

  16. SOLVENT-FREE ALTERNATIVES TO ORGANIC SYNTHESES USING MICROWAVES

    EPA Science Inventory

    Microwave irradiation has been used for a variety of synthetic 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 mic...

  17. 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.

  18. 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.

  19. 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

    Flegal, Matthew; Blimkie, Melinda; Roch-Lefevre, Sandrine; Gregoire, Eric; Klokov, Dmitry

    2013-12-05

    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.

  20. 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.