WorldWideScience

Sample records for acid direct comparison

  1. Comparison of indirect and direct quantification of glycidol fatty acid ester in edible oils.

    Science.gov (United States)

    Shimizu, Masao; Kudo, Naoto; Shiro, Hiroki; Yasunaga, Koichi; Masukawa, Yoshinori; Katsuragi, Yoshihisa; Yasumasu, Takeshi

    2010-01-01

    Two different methods for determining the levels of glycidol fatty acid esters (GEs) in edible oil-the German official indirect method and the direct LC-MS method-are compared. In some cases, the indirect method showed lower GE levels than the direct method. This was investigated using model studies, which revealed two possible causative factors during the acid treatment of the indirect method: (1) incomplete elimination of GE in oil that was high in GEs initially and (2) generation of GEs and/or its relevant compounds in oil that was rich in partial acylglycerol. Both these factors contributed to the subsequent underestimation of GE levels. The above technical limitations of the indirect method found in the present study has led to the inference that the direct method can more precisely determine the GE levels for a wider range of fats and oil products than the indirect method.

  2. Comparison of direct infusion and on-line liquid chromatography/electrospray ionization mass spectrometry for the analysis of nucleic acids.

    Science.gov (United States)

    Huber, C G; Krajete, A

    2000-07-01

    The applicability of ion-pair reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometry (IP-RP-HPLC/ESI-MS) and direct infusion/ESI-MS to the characterization of nucleic acid mixtures was evaluated by the analysis of the reaction products obtained from solid-phase synthesis of a 39-mer oligonucleotide. IP-RP-HPLC/ESI-MS was performed using 200 microm i.d. capillary columns packed with octadecylated, micropellicular poly(styrene-divinylbenzene) particles and applying gradients of acetonitrile in 50 mM triethylammonium bicarbonate (TEAB). Three different solvent systems were utilized for direct infusion/ESI-MS with removal of metal cations by on-line cation exchange: (1) 10 mM triethylamine (TEA) in 50% aqueous acetonitrile, (2) 2.2 mM TEA, 400 mM hexafluoro-2-propanol (HFIP) in 20% aqueous methanol and (3) 50 mM TEAB in 10% aqueous acetonitrile. Owing to its separation capability, the highest selectivity and specificity were achieved with IP-RP-HPLC/ESI-MS, which, apart form the 39-mer target sequence, allowed the identification of two isobutyryl-protected target sequences and a 10-mer and 20-mer failure sequence. Direct infusion/ESI-MS with TEA-acetonitrile or TEA-HFIP-methanol as solvent revealed signals for the 39-mer in the m/z range 700-1600. The presence of derivatives containing one, two, three and four isobutyryl groups indicated that the hydrolysis of the protecting groups after solid-phase synthesis was not complete. Failure sequences could not be identified by direct infusion/ESI-MS under conditions favoring multiple charging of the analytes owing to the high chemical background and coincidental overlapping of m/z signals. However, efficient charge state reduction upon addition of carbonic acid to the electrosprayed solvent shifted the signals of the 39-mer and derivatives to m/z values >2400 and allowed the detection of seven different failure sequences, ranging from the 8-mer to the 23-mer, in the mixture.

  3. Direct Oxidation of Ethene to Acetic Acid

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Direct oxidation of ethene to acetic acid over Pd-SiW12/SiO2 catalysts prepared by several methods was studied. A better method for reducing palladium composition of the catalysts was found. Acetic acid was obtained with selectivity of 82.7% and once-through space time yield (STY) of 257.4 g/h×L.

  4. Direct amino acid analyses of mozzarella cheese.

    Science.gov (United States)

    Hoskins, M N

    1985-12-01

    The amino acid content of mozzarella (low moisture, part skim milk) and asadero cheeses was determined by the column chromatographic method. Data from the direct analyses of the mozzarella cheeses were compared with the calculated amino acid composition reported in tables in Agriculture Handbook No. 8-1. Phenylalanine and tyrosine contents were found to be higher in the direct analyses than in the calculated data in Handbook No. 8-1 (1.390 gm and 1.127 gm for phenylalanine, and 1.493 gm and 1.249 gm for tyrosine per 100 gm edible portion, respectively). That is of particular concern in the dietary management of phenylketonuria, in which accuracy in computing levels of phenylalanine and tyrosine is essential.

  5. New directions in social comparison research

    NARCIS (Netherlands)

    Buunk, BP; Mussweiler, T

    2001-01-01

    This article notices that social comparison theory has developed from being a focused theoretical statement on the use of others for self-evaluation into a lively and varied area of research encompassing many different paradigms, approaches and applications. A recent 'renaissance' in social comparis

  6. Comparison of direct and indirect radionuclide cystography

    Energy Technology Data Exchange (ETDEWEB)

    Bower, G.; Lovegrove, F.T.; Geijsel, H.; Van der Schaff, A.; Guelfi, G.

    1985-05-01

    Thirty children were studied using both direct (catheter) and indirect techniques of radionuclide cystography. Of 54 ureters able to be compared, six showed vesicoureteric reflux (VUR) on the direct study but were read as negative on the indirect cystogram, and five showed no reflux on the direct cystogram but were read as positive for VUR on the indirect study. Regarding ureters read as true positives on indirect study, if that ureter has ever shown reflux at any time, or if it drained a scarred kidney specificity was improved to 97% without changing the sensitivity. Concerns about the validity of indirect cystogram results and the ease of assessment and low radiation dose from the direct cystogram has made direct cystography our preferred technique.

  7. Direct concurrent measurement of urinary vanillylmandelic acid, 5-hydroxyindoleacetic acid and homovanillic acid by HPLC. Three methodologies compared.

    Science.gov (United States)

    van Haard, P M; Wielders, J P; Wikkerink, J B

    1987-01-01

    Three different direct HPLC methods for the determination of 3-methoxy-4-hydroxymandelic acid (VMA, vanillylmandelic acid), 5-hydroxyindoleacetic acid (5-HIAA) and 3-methoxy-4-hydroxyphenylacetic acid (HVA, homovanillic acid) in urine were compared: two spectrofluorometric methods, applying discontinuous gradients, and one serial coulometric linear gradient method. The imprecision study (n = 6) revealed comparable coefficients of variation (CV), intra-assay ranging 1.4-11.1%, and inter-assay ranging 5.9-11.8% for physiological and moderately elevated levels of VMA, 5-HIAA and HVA. All methods showed good linearities up to 100 mumol/L for each of the three compounds studied. Analytical recoveries were 97-114% for VMA, 87-103% for 5-HIAA, and 80-95% for HVA. Recoveries were not dependent on urinary relative densities in the range 1.010-1.030 kg/L or on protein content (prior to acidification) in the range 0.1-3 g/L, or on the pH of conservation in the range 2-5 or on storage temperature in the range -20 - +22 degrees C for three weeks. The distributed-sample comparison revealed acceptable correlations and clinically unimportant accuracy differences between the methods. It is concluded that direct fluorometric and electrochemical HPLC methods can be used in the determination of major catecholamine and serotonin metabolites in human urine for clinical diagnosis and follow-up of neural crest and carcinoid tumours.

  8. Design and Comparison Direct Torque Control Techniques for Induction Motors

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Kazmierkowski, Marian P.; Zelechowski, Marcin

    2005-01-01

    In this paper a comparison of two significant control methods of induction motor are presented. The first one is a classical Direct Torque and Flux Control (DTC) and is compared with a scheme, which uses Space Vector Modulator (DTC-SVM). A comparison in respect to dynamic and steady state...

  9. Study of Synthesis of Copoly (lactic acid/glycolic acid) by Direct Melt Polycondensation

    Institute of Scientific and Technical Information of China (English)

    LAN Ping; GAO Qin-wei; SHAO Hui-li; HU Xue-chao

    2005-01-01

    A two steps direct copolymerisation process was developed. The first step is to produce oligomer and then the oligomer of lactic acid/glycolic acid (90/10) is polymerized with binary catalyst tin chloride dihydrate/ptoluenesulfonic acid. In this way, the direct synthesis of copoly (lactic acid/glycolic acid) without any organic solvent was investigated. The properties and structures of products were characterized by nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), X-ray diffraction and so on. The results show that comparatively high molecular weight copolymer of lactic acid and glycolic acid can be prepared by direct processing under appropriate technological conditions.

  10. Positive direct antiglobulin tests due to clavulanic acid.

    Science.gov (United States)

    Williams, M E; Thomas, D; Harman, C P; Mintz, P D; Donowitz, G R

    1985-01-01

    Clavulanic acid, a beta-lactamase inhibitor, was found to be associated with the development of a positive direct antiglobulin test. Of 23 antibiotic courses in patients treated with ticarcillin, clavulanic acid, and tobramycin, 10 (43.5%) developed positive direct antiglobulin tests versus 2 of 26 (7.7%) patients treated with piperacillin and tobramycin (P = 0.0044). In vitro immunohematological studies showed that clavulanic acid caused a nonimmunologic adsorption of plasma proteins onto the erythrocyte surface. Hemolysis was not associated with such nonimmunologic adsorption. However, the resulting positive antiglobulin test might delay cross matching of blood products for transfusions or interfere with the evaluation of true immune-mediated hemolytic anemia. PMID:3872623

  11. Low contaminant formic acid fuel for direct liquid fuel cell

    Science.gov (United States)

    Masel, Richard I.; Zhu, Yimin; Kahn, Zakia; Man, Malcolm

    2009-11-17

    A low contaminant formic acid fuel is especially suited toward use in a direct organic liquid fuel cell. A fuel of the invention provides high power output that is maintained for a substantial time and the fuel is substantially non-flammable. Specific contaminants and contaminant levels have been identified as being deleterious to the performance of a formic acid fuel in a fuel cell, and embodiments of the invention provide low contaminant fuels that have improved performance compared to known commercial bulk grade and commercial purified grade formic acid fuels. Preferred embodiment fuels (and fuel cells containing such fuels) including low levels of a combination of key contaminants, including acetic acid, methyl formate, and methanol.

  12. A Comparison between Direct and Indirect Laser Sintering of Metals

    Institute of Scientific and Technical Information of China (English)

    Montasser M.Dewidar; Jae-Kyoo LIM; K.W.Dalgarno

    2008-01-01

    Layer manufacture technologies are gaining increasing attention in the manufacturing for the production of polymer mould tooling. Layer manufacture techniques can be used in this potential manufacturing area to produce tooling either indirectly or directly, and powder metal based layer manufacture systems are considered as an effective way of producing rapid tooling. Mechanical properties and accuracy are critical for tooling. This paper reports the results of an experimental study examining the potential of layer manufacturing processes to deliver production tooling for polymer manufacture. A comparison between indirectly selective laser sintering and directly selective laser sintering to provide the tooling was reported. Three main areas were addressed during the study: mechanical strength, accuracy, and build rate. Overviews of the results from the studies were presented.

  13. Direct conversion of cellulose to glycolic acid with a phosphomolybdic acid catalyst in a water medium

    KAUST Repository

    Zhang, Jizhe

    2012-08-03

    Direct conversion of cellulose to fine chemicals has rarely been achieved. We describe here an eco-benign route for directly converting various cellulose-based biomasses to glycolic acid in a water medium and oxygen atmosphere in which heteromolybdic acids act as multifunctional catalysts to catalyze the hydrolysis of cellulose, the fragmentation of monosaccharides, and the selective oxidation of fragmentation products. With commercial α-cellulose powder as the substrate, the yield of glycolic acid reaches 49.3%. This catalytic system is also effective with raw cellulosic biomass, such as bagasse or hay, as the starting materials, giving rise to remarkable glycolic acid yields of ∼30%. Our heteropoly acid-based catalyst can be recovered in solid form after reaction by distilling out the products and solvent for reuse, and it exhibits consistently high performance in multiple reaction runs. © 2012 American Chemical Society.

  14. COMPARISON OF TDOA LOCATION ALGORITHMS WITH DIRECT SOLUTION METHOD

    Institute of Scientific and Technical Information of China (English)

    Li Chun; Liu Congfeng; Liao Guisheng

    2011-01-01

    For Time Difference Of Arrival (TDOA) location based on multi-ground stations scene,two direct solution methods are proposed to solve the target position in TDOA location.Therein,the solving methods are realized in the rectangular and polar coordinates.On the condition of rectangular coordinates,first of all,it solves the radial range between the target and reference station,then calculates the location of the target.In the case of polar coordinates,the azimuth between the target and reference station is solved first,then the radial range between the target and reference station is figured out,finally the location of the target is obtained.Simultaneously,the simulation and comparison analysis are given in detail,and show that the polar solving method has the better fuzzy performance than that of rectangular coordinate.

  15. (-)-Hydroxycitric Acid Nourishes Protein Synthesis via Altering Metabolic Directions of Amino Acids in Male Rats.

    Science.gov (United States)

    Han, Ningning; Li, Longlong; Peng, Mengling; Ma, Haitian

    2016-08-01

    (-)-Hydroxycitric acid (HCA), a major active ingredient of Garcinia Cambogia extracts, had shown to suppress body weight gain and fat accumulation in animals and humans. While, the underlying mechanism of (-)-HCA has not fully understood. Thus, this study was aimed to investigate the effects of long-term supplement with (-)-HCA on body weight gain and variances of amino acid content in rats. Results showed that (-)-HCA treatment reduced body weight gain and increased feed conversion ratio in rats. The content of hepatic glycogen, muscle glycogen, and serum T4 , T3 , insulin, and Leptin were increased in (-)-HCA treatment groups. Protein content in liver and muscle were significantly increased in (-)-HCA treatment groups. Amino acid profile analysis indicated that most of amino acid contents in serum and liver, especially aromatic amino acid and branched amino acid, were higher in (-)-HCA treatment groups. However, most of the amino acid contents in muscle, especially aromatic amino acid and branched amino acid, were reduced in (-)-HCA treatment groups. These results indicated that (-)-HCA treatment could reduce body weight gain through promoting energy expenditure via regulation of thyroid hormone levels. In addition, (-)-HCA treatment could promote protein synthesis by altering the metabolic directions of amino acids. Copyright © 2016 John Wiley & Sons, Ltd.

  16. Direct synthesis of formic acid from carbon dioxide by hydrogenation in acidic media.

    Science.gov (United States)

    Moret, Séverine; Dyson, Paul J; Laurenczy, Gábor

    2014-06-02

    The chemical transformation of carbon dioxide into useful products becomes increasingly important as CO2 levels in the atmosphere continue to rise as a consequence of human activities. In this article we describe the direct hydrogenation of CO2 into formic acid using a homogeneous ruthenium catalyst, in aqueous solution and in dimethyl sulphoxide (DMSO), without any additives. In water, at 40 °C, 0.2 M formic acid can be obtained under 200 bar, however, in DMSO the same catalyst affords 1.9 M formic acid. In both solvents the catalysts can be reused multiple times without a decrease in activity. Worldwide demand for formic acid continues to grow, especially in the context of a renewable energy hydrogen carrier, and its production from CO2 without base, via the direct catalytic carbon dioxide hydrogenation, is considerably more sustainable than the existing routes.

  17. Performance Comparison of New Combinations of Acids with Mud Acid in Sandstone Acidizing

    Directory of Open Access Journals (Sweden)

    Mian Umer Shafiq

    2014-01-01

    Full Text Available The aim of this research is to find the best suitable acid to acidize undamaged low permeable sandstone formation Stimulation of sandstone formations is a challenging task, which involves several chemicals and physical interactions of the acid with the formation. Mud acid has been successfully used to stimulate sandstone reservoirs for a number of years. Matrix acidizing may also be used to increase formation permeability in undamaged wells. The change may be up to 50 to 100% with the mud acid. For any acidizing process, the selection of acid (Formulation and Concentration and the design (Pre-flush, Main Acid, After-flush is very important. Different researchers are using different combinations of acids with different concentrations to get the best results for acidization. Mainly the common practice is combination of Hydrochloric Acid- Hydrofluoric with Concentration (3% HF-12% HCl. This study presents the results of a laboratory investigation of Orthophosphoric acid instead of hydrochloric acid in one combination and the second combination is Fluoboric and formic acid and the third one is formic and hydrofluoric acid. The results are compared with the mud acid and the results analyzed are porosity, permeability, strength, color change and FESEM Analysis. All of these new combinations shows that these have the potential to be used as acidizing acids on sandstone formations.

  18. Comparison and combination effects on antioxidant power of curcumin with gallic acid, ascorbic acid, and xanthone.

    Science.gov (United States)

    Naksuriya, Ornchuma; Okonogi, Siriporn

    2015-04-01

    Curcumin has been extensively reported as a potential natural antioxidant. However, there was no data on activity comparison as well as the biological interactions of curcumin with other natural antioxidants. The aim of the present study was to investigate the antioxidant power of curcumin in comparison with three important natural antioxidants; gallic acid, ascorbic acid, and xanthone on free radical scavenging action and their combination effects on this activity. The results indicated that the activities of these compounds were dose-dependent. The 50% effective concentration (EC50) of curcumin was found to be 11 μg/mL. Curcumin showed significantly higher antioxidant activity than ascorbic acid and xanthone but less than gallic acid. Interestingly, curcumin revealed synergistic antioxidant effect when combined with gallic acid whereas the antagonistic effect occurred in curcumin combination with ascorbic acid or xanthone. These results suggest that curcumin-gallic acid combination is the potential antioxidant mixture to be used in place of the individual substance whereas using of curcumin in combination with ascorbic acid or xanthone should be avoid.

  19. A direct potential fitting RKR method: Semiclassical vs. quantal comparisons

    Science.gov (United States)

    Tellinghuisen, Joel

    2016-12-01

    Quantal and semiclassical (SC) eigenvalues are compared for three diatomic molecular potential curves: the X state of CO, the X state of Rb2, and the A state of I2. The comparisons show higher levels of agreement than generally recognized, when the SC calculations incorporate a quantum defect correction to the vibrational quantum number, in keeping with the Kaiser modification. One particular aspect of this is better agreement between quantal and SC estimates of the zero-point vibrational energy, supporting the need for the Y00 correction in this context. The pursuit of a direct-potential-fitting (DPF) RKR method is motivated by the notion that some of the limitations of RKR potentials may be innate, from their generation by an exact inversion of approximate quantities: the vibrational energy Gυ and rotational constant Bυ from least-squares analysis of spectroscopic data. In contrast, the DPF RKR method resembles the quantal DPF methods now increasingly used to analyze diatomic spectral data, but with the eigenvalues obtained from SC phase integrals. Application of this method to the analysis of 9500 assigned lines in the I2A ← X spectrum fails to alter the quantal-SC disparities found for the A-state RKR curve from a previous analysis. On the other hand, the SC method can be much faster than the quantal method in exploratory work with different potential functions, where it is convenient to use finite-difference methods to evaluate the partial derivatives required in nonlinear fitting.

  20. Direct inhibition of retinoic acid catabolism by fluoxetine.

    Science.gov (United States)

    Hellmann-Regen, Julian; Uhlemann, Ria; Regen, Francesca; Heuser, Isabella; Otte, Christian; Endres, Matthias; Gertz, Karen; Kronenberg, Golo

    2015-09-01

    Recent evidence from animal and human studies suggests neuroprotective effects of the SSRI fluoxetine, e.g., in the aftermath of stroke. The underlying molecular mechanisms remain to be fully defined. Because of its effects on the cytochrome P450 system (CYP450), we hypothesized that neuroprotection by fluoxetine is related to altered metabolism of retinoic acid (RA), whose CYP450-mediated degradation in brain tissue constitutes an important step in the regulation of its site-specific auto- and paracrine actions. Using traditional pharmacological in vitro assays, the effects of fluoxetine on RA degradation were probed in crude synaptosomes from rat brain and human-derived SH-SY5Y cells, and in cultures of neuron-like SH-SY5Y cells. Furthermore, retinoid-dependent effects of fluoxetine on neuronal survival following glutamate exposure were investigated in rat primary neurons cells using specific retinoid receptor antagonists. Experiments revealed dose-dependent inhibition of synaptosomal RA degradation by fluoxetine along with dose-dependent increases in RA levels in cell cultures. Furthermore, fluoxetine's neuroprotective effects against glutamate excitotoxicity in rat primary neurons were demonstrated to partially depend on RA signaling. Taken together, these findings demonstrate for the first time that the potent, pleiotropic antidepressant fluoxetine directly interacts with RA homeostasis in brain tissue, thereby exerting its neuroprotective effects.

  1. A high-performance direct transmethylation method for total fatty acids assessment in biological and foodstuff samples.

    Science.gov (United States)

    Castro-Gómez, Pilar; Fontecha, Javier; Rodríguez-Alcalá, Luis M

    2014-10-01

    Isolation is the main bottleneck in the analysis of fatty acids in biological samples and foods. In the last few decades some methods described direct derivatization procedures bypassing these steps. They involve the utilization of methanolic HCL or BF3 as catalysts, but several evidences from previous works suggest these reagents are unstable, lead to the formation of artifacts and alter the distribution of specific compounds as hydroxy fatty acids or CLA. However, the main issue is that they are excellent esterification reagents but poor in transterification, being not suitable for the analysis of all lipid classes and leading to erroneous composition quantitations. The present research work is a comprehensive comparison of six general methylation protocols using base, acid or base/acid catalysts plus a proposed method in the analysis of total fatty acids in lipid standards mixtures, foodstuff and biological samples. The addition of aprotic solvents to the reaction mixture to avoid alterations was also tested. Results confirmed that procedures solely involving acid catalyst resulted in incomplete derivatizations and alteration of the fatty acid profile, partially corrected by addition of the aprotic solvent. The proposed method combining sodium methoxyde and sulfuric acid showed absence of alteration of the FAME profile and the best values for response factors (short chain fatty acids to PUFA), accuracy in the determination of total cholesterol and derivatization performance, thus showing a high reliability in the determination of the total fatty acid composition in biological samples and foods.

  2. Experimental Comparison of Inquiry and Direct Instruction in Science

    Science.gov (United States)

    Cobern, William W.; Schuster, David; Adams, Betty; Applegate, Brooks; Skjold, Brandy; Undreiu, Adriana; Loving, Cathleen C.; Gobert, Janice D.

    2010-01-01

    There are continuing educational and political debates about "inquiry" versus "direct" teaching of science. Traditional science instruction has been largely direct but in the US, recent national and state science education standards advocate inquiry throughout K-12 education. While inquiry-based instruction has the advantage of modelling aspects…

  3. A Comparison of Paradoxical and Nonparadoxical Interpretations and Directives.

    Science.gov (United States)

    Feldman, Daniel A.; And Others

    1982-01-01

    Explored the effects of consistent and inconsistent combinations of paradoxical and nonparadoxical interpretations and directives in brief counseling with moderately depressed college students. Paradoxical interpretations were associated with more symptom remission than were nonparadoxical interpretations. The nature of the directives students…

  4. Ginsenoside Rb1 directly scavenges hydroxyl radical and hypochlorous acid.

    Science.gov (United States)

    Lü, Jian-Ming; Weakley, Sarah M; Yang, Zhen; Hu, Ming; Yao, Qizhi; Chen, Changyi

    2012-01-01

    Reactive oxygen species (ROS) have been implicated in a variety of inflammatory diseases including cardiovascular disease (CVD), cancer, diabetes, Alzheimer's disease, autism, cataracts and aging. When endogenous mechanisms for the maintenance of redox homeostasis are overwhelmed, dietary intake of antioxidants contributes substantially to balancing the body's oxidant/antioxidant status. Ginsenosides are thought to be primarily responsible for the pharmacological effect of P. ginseng root extracts on oxidative stress and inflammation. However, little is known about the underlying antioxidant mechanisms of individual ginsenoside; specifically, the reactivity of ginsenoside Rb1 with ROS has not been well studied. We found that Rb1 can significantly and selectively reduce hydroxyl radical (●OH) and hypochlorous acid (HOCl), two of the strongest ROS, with unique molecular mechanisms in a cell-free system. Rb1 directly scavenges the ●OH and protects plasmid DNA from damage induced by ●OH. ●OH likely attacks the double bond on the side chain of Rb1 as well as hydrogen atoms adjacent to the -OH groups, including those of sugar moieties. Rb1 also shows a high reactivity to HOCl and effectively inhibits HOCl-induced tyrosine chlorination in a cell free system. HOCl is added to the double bond of Rb1; the -Cl group and -OH group of HOCl possibly bond at C-24 and C-25 of Rb1 based on the regioselectivity of Markovnikov's Rule. To our knowledge, this is the first demonstration that ginsenoside Rb1 scavenges HOCl and protects tyrosine from HOCl-induced chlorination. Thus, this study reveals unique antioxidant mechanisms of individual ginsenoside Rb1, which may contribute to the pharmacological effect of P. ginseng and to the development of effective strategies for clinical applications of ginsenosides.

  5. Direct comparison of optical lattice clocks with an intercontinental baseline of 9 000 km

    CERN Document Server

    Hachisu, H; Nagano, S; Gotoh, T; Nogami, A; Ido, T; Falke, St; Huntemann, N; Grebing, C; Lipphardt, B; Lisdat, Ch; Piester, D

    2014-01-01

    We have demonstrated a direct frequency comparison between two $^{87}{\\rm Sr}$ lattice clocks operated in intercontinentally separated laboratories in real time. Two-way satellite time and frequency transfer technique based on the carrier phase was employed for a direct comparison with a baseline of 9 000 km between Japan and Germany. A clock comparison was achieved for 83 640 s resulting in a fractional difference of $(1.1\\pm1.6) \\times 10^{-15}$, where the statistical part is the biggest contribution to the uncertainty. This measurement directly confirms the agreement of the two optical clocks on an intercontinental scale.

  6. Beef, chicken and lamb fatty acid analysis--a simplified direct bimethylation procedure using freeze-dried material.

    Science.gov (United States)

    Lee, M R F; Tweed, J K S; Kim, E J; Scollan, N D

    2012-12-01

    When fractionation of meat lipids is not required, procedures such as saponification can be used to extract total fatty acids, reducing reliance on toxic organic compounds. However, saponification of muscle fatty acids is laborious, and requires extended heating times, and a second methylation step to convert the extracted fatty acids to fatty acid methyl esters prior to gas chromatography. Therefore the development of a more rapid direct methylation procedure would be of merit. The use of freeze-dried material for analysis is common and allows for greater homogenisation of the sample. The present study investigated the potential of using freeze-dried muscle samples and a direct bimethylation to analyse total fatty acids of meat (beef, chicken and lamb) in comparison with a saponification procedure followed by bimethylation. Both methods compared favourably for all major fatty acids measured. There was a minor difference in relation to the C18:1 trans 10 isomer with a greater (Psaponification. However, numerically the difference was small and likely as a result of approaching the limits of isomer identification by single column gas chromatography. Differences (Psaponification to analyse total fatty acids from muscle samples.

  7. Assessing Students' Writing Skills: A Comparison of Direct & Indirect Methods.

    Science.gov (United States)

    Koffler, Stephen L.

    This research examined the results from direct and indirect writing assessments to determine the most effective method of discrimination. The New Jersey State Department of Education developed a test for ninth-grade students which was designed to measure the ability to apply writing mechanics to written text and to communicate effectively in…

  8. Toward a direct comparison of field and laboratory goniometer measurements

    NARCIS (Netherlands)

    Dangel, S.; Verstraete, M.; Schopfer, J.; Kneubuehler, M.; Schaepman, M.E.; Itten, K.I.

    2005-01-01

    Field and laboratory goniometers are widely used in the remote sensing community to assess spectrodirectional reflection properties of selected targets. Even when the same target and goniometer system are used, field and laboratory results cannot directly be compared due to inherent differences, mai

  9. Comparison of vertebrae and otoliths measured directly and from radiographs

    DEFF Research Database (Denmark)

    Pedersen, Jens

    1997-01-01

    It is general practice among fish ecologists to use indigestible remains such as vertebrae and otoliths in fish stomachs to determine the nature and size of their prey. However, estimation of the relationship between fish length and vertebrae size is a time consuming process when using vertebrae ...... was established at least 10 times faster using radiographs than when direct measurements were used. (C) 1997 Elsevier Science B.V....

  10. Direct esterification of ammonium salts of carboxylic acids

    Science.gov (United States)

    Halpern, Yuval

    2003-06-24

    A non-catalytic process for producing esters, the process comprising reacting an ammonium salt of a carboxylic acid with an alcohol and removing ammonia from the reaction mixture. Selectivities for the desired ester product can exceed 95 percent.

  11. The Comparison of the Direct Method and the Communicative Approach

    Institute of Scientific and Technical Information of China (English)

    王丽葵

    2011-01-01

    一、 Major Characteristics of the Direct Method and the Communicative Approach The characteristics of the communicative Approach are as follows:(1) The teaching content takes language function as the key link,which is fixed up in accordance with the different demands of studying object.For example,the demands of the scientist and technologist,the translator,the foreign language teacher,the tourist adviser,the diplomatic personnel and the economic worker are different from each other,so the most necessary language materials for achieving certain communication are chosen which are usually the most common structure form.

  12. Comparison between direct and indirect cooling core catchers

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Jung Soo; Lee, Jong Ho; Bae, Byung Hwan [Korea Hydro and Nuclear Power Co., Ltd., Seoul (Korea, Republic of)

    2012-10-15

    The European nuclear design requirements, which should be satisfied by nuclear reactors in Europe, usually recommend a so called core catcher, which is a molten core ex vessel cooling facility, to manage a severe accident at a nuclear reactor. Two different types of core catcher concepts are compared to determine their abilities to manage severe accidents and cool core melts. The study reveals that direct cooling is better for cooling capacity and is convenient to construct, while indirect cooling is better for the management of a severe accident.

  13. Selective synthesis of thiodiglycol dicarboxylic acid esters via -TsOH/C-catalysed direct esterification

    Indian Academy of Sciences (India)

    Dahong Jiang; Min Huang

    2012-09-01

    The esterification of thiodiglycol and long alkyl-chain carboxylic acids is reported. Reaction of thiodiglycol with carboxylic acid via -TsOH/C-catalysed direct esterification afforded thiodiglycol dicarboxylic acid esters in good yields and chemoselectivity. The use of immobilized -TsOH on activated carbon as catalyst is crucial for the transformation.

  14. Complexation of uranium(VI) with aromatic acids in aqueous solution. A comparison of hydroxamic acids and benzoic acid

    Energy Technology Data Exchange (ETDEWEB)

    Glorius, M.; Moll, H.; Bernhard, G. [Forschungszentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. fuer Radiochemie

    2007-07-01

    The complex formation of uranium(VI) with salicylhydroxamic,benzohydroxamic, and benzoic acid in 0.1 M NaClO{sub 4} was studied by UV-vis spectroscopy at pH 3 and 4. Uranium(VI) species of the type M{sub p}L{sub q}H{sub r} were identified from the UV-vis spectra in all three systems. An increase in the absorption combined with a blue shift of the absorption maxima in comparison to the bands of the free uranyl ion of 22.5 {+-} 2 nm was observed in the uranium (VI)-salicylhydroxamic acid-system. Besides indications for a 1:2 complex, the formation of a 1:1 complex with a stability constant of log {beta}{sub 111} = 17.12 {+-} 0.10 could be demonstrated by its individual absorption spectrum and molar absorption coefficient. Also in the uranium(VI)-benzohydroxamic acid-system a blue shift of the absorption maxima in comparison to the bands of the free uranyl ion of 27 {+-} 1.4 nm indicate the complex formation. The stability constants are log {beta}{sub 110} = 7.96 {+-} 0.05 for UO{sub 2}[C{sub 6}H{sub 4}CONHO]{sup +} and log {beta}{sub 120} = 15.25 {+-} 0.11 for UO{sub 2}[C{sub 6}H{sub 4}CONHO]{sub 2}. In contrast to the hydroxamic acids, benzoic acid shows a red shift of the absorption maxima of 2.5 {+-} 2 nm. Only the 1:1 complex UO{sub 2}[C{sub 6}H{sub 4}COO]{sup +} with a stability constant of log {beta}{sub 110} = 3.37 {+-} 0.14 is existent. An estimate is made in order to discuss the dependencies observed in the absorption spectra in relation to possible coordination modes of uranium(VI). The strength of the complex formation between uranyl and the three aromatic acids is discussed. (orig.)

  15. Kriging direct and indirect estimates of sulfate deposition: A comparison. Forest Service research paper

    Energy Technology Data Exchange (ETDEWEB)

    Reams, G.A.; Huso, M.M.P.; Vong, R.J.; McCollum, J.M.

    1997-08-01

    Due to logistical and cost constraints, acidic deposition is rarely measured at forest research or sampling locations. A crucial first step to assessing the effects of acid rain on forests is an accurate estimate of acidic deposition at forest sample sites. The authors examine two methods (direct and indirect) for estimating sulfate deposition at atmospherically unmonitored forest sites. The direct method only uses directly measured deposition data, while the indirect method additionally incorporates precipitation measurements from a spatially denser network of monitoring sites. Sulfate deposition values were estimated by point kriging using both the direct and indirect methods. By using the supplemental data from the precipitation monitoring network, estimates of sulfate deposition improved substantially, particularly at sites that are relatively isolated to the acid deposition monitoring network. Cross-validated procedures indicate that by using the indirect method, a reduction of approximately 20 to 25 percent in the predicted error sum of squares occurred.

  16. Development of a method for the direct fermentation of semolina by selected sourdough lactic acid bacteria.

    Science.gov (United States)

    Alfonzo, Antonio; Urso, Valeria; Corona, Onofrio; Francesca, Nicola; Amato, Gaetano; Settanni, Luca; Di Miceli, Giuseppe

    2016-12-19

    Three obligately heterofermentative lactic acid bacteria (LAB) strains (Lactobacillus sanfranciscensis PON100336, Leuconostoc citreum PON10079 and Weissella cibaria PON10030) were used in this study as a multi-species starter culture for sourdough production. The starter inoculum was prepared and propagated in sterile semolina extract (SSE) broth. Acidification kinetics, microbiological counts detected on specific media for sourdough LAB, polymorphic profile comparison and species-specific PCRs evidenced a stability of the liquid inoculum over time determining its suitability for direct addition to semolina. In order to validate this innovative method for the production of durum wheat (Triticum durum Desf) sourdoughs, 15 semolinas (from ten old and five modern genotypes cultivated in Sicily, southern Italy) were used to prepare the SSEs and to produce sourdoughs and finally breads. Chemical and microbiological analyses of the sourdoughs and the evaluation of the quality parameters (weight loss, height, crumb and crust colour, image analysis and volatile organic compound generation) of the resulting breads indicated that the direct addition of the liquid inocula propagated in SSE is a valuable method to stabilise the production of sourdoughs. The differences registered during the technological characterisation of the breads were underlined by the sensory tests and the multivariate analysis and are mainly imputable to the type of semolina.

  17. Direct comparison of XAFS spectroscopy and sequential extraction for arsenic speciation in coal

    Science.gov (United States)

    Huggins, Frank E.; Huffman, G.P.; Kolker, A.; Mroczkowski, S.; Palmer, C.A.; Finkelman, R.B.

    2000-01-01

    The speciation of arsenic in an Ohio bituminous coal and a North Dakota lignite has been examined by the complementary methods of arsenic XAFS spectroscopy and sequential extraction by aqueous solutions of ammonium acetate, HCl, HF, and HNO3. In order to facilitate a more direct comparison of the two methods, the arsenic XAFS spectra were obtained from aliquots of the coal prepared after each stage of the leaching procedure. For the aliquots, approximately linear correlations (r2 > 0.98 for the Ohio coal, > 0.90 for the ND lignite) were observed between the height of the edge-step in the XAFS analysis and the concentration of arsenic measured by instrumental neutron activation analysis. Results from the leaching sequence indicate that there are two major arsenic forms present in both coals; one is removed by leaching with HCl and the other by HNO3. Whereas the XAFS spectral signatures of the arsenic leached by HCl are compatible with arsenate for both coals, the arsenic leached by HNO3 is identified as arsenic associated with pyrite for the Ohio coal and as an As3+ species for the North Dakota lignite. Minor arsenate forms persist in both coals after the final leaching with nitric acid. The arsenate forms extracted in HCl are believed to be oxidation products derived from the other major arsenic forms upon exposure of the pulverized coals to air.

  18. Comparison of NWP wind speeds and directions to measured wind speeds and directions

    DEFF Research Database (Denmark)

    Astrup, Poul; Mikkelsen, Torben

    Numerical Weather Predictions (NWP) of wind speed and direction has been compared to measurements for seven German sites for nuclear power plants, and for Risø, the site of the Danish nuclear research reactors now being decommissioned . For the German sites the data cover approximately three month...

  19. Case study: Comparison of motivation for achieving higher performance between self-directed and manager-directed aerospace engineering teams

    Science.gov (United States)

    Erlick, Katherine

    "The stereotype of engineers is that they are not people oriented; the stereotype implies that engineers would not work well in teams---that their task emphasis is a solo venture and does not encourage social aspects of collaboration" (Miner & Beyerlein, 1999, p. 16). The problem is determining the best method of providing a motivating environment where design engineers may contribute within a team in order to achieve higher performance in the organization. Theoretically, self-directed work teams perform at higher levels. But, allowing a design engineer to contribute to the team while still maintaining his or her anonymity is the key to success. Therefore, a motivating environment must be established to encourage greater self-actualization in design engineers. The purpose of this study is to determine the favorable motivational environment for design engineers and describe the comparison between two aerospace design-engineering teams: one self-directed and the other manager directed. Following the comparison, this study identified whether self-direction or manager-direction provides the favorable motivational environment for operating as a team in pursuit of achieving higher performance. The methodology used in this research was the case study focusing on the team's levels of job satisfaction and potential for higher performance. The collection of data came from three sources, (a) surveys, (b) researcher observer journal and (c) collection of artifacts. The surveys provided information regarding personal behavior characteristics, potentiality for higher performance and motivational attributes. The researcher journal provided information regarding team dynamics, individual interaction, conflict and conflict resolution. The milestone for performance was based on the collection of artifacts from the two teams. The findings from this study illustrated that whether the team was manager-directed or self-directed does not appear to influence the needs and wants of the

  20. Acid-Base Pairs in Lewis Acidic Zeolites Promote Direct Aldol Reactions by Soft Enolization.

    Science.gov (United States)

    Lewis, Jennifer D; Van de Vyver, Stijn; Román-Leshkov, Yuriy

    2015-08-17

    Hf-, Sn-, and Zr-Beta zeolites catalyze the cross-aldol condensation of aromatic aldehydes with acetone under mild reaction conditions with near quantitative yields. NMR studies with isotopically labeled molecules confirm that acid-base pairs in the Si-O-M framework ensemble promote soft enolization through α-proton abstraction. The Lewis acidic zeolites maintain activity in the presence of water and, unlike traditional base catalysts, in acidic solutions.

  1. Comparison of NWP wind speeds and directions to measured wind speeds and directions

    Energy Technology Data Exchange (ETDEWEB)

    Astrup, P.; Mikkelsen, Torben

    2010-09-15

    Numerical Weather Predictions (NWP) of wind speed and direction has been compared to measurements for seven German sites for nuclear power plants, and for Risoe, the site of the Danish nuclear research reactors now being decommissioned . For the German sites the data cover approximately three month, the NWP data from Austrian Meteorological and Geophysical Office, AMGO, cover 5th January to 31st March 2009 with two daily sets of analysis and 1 to 48 hours forecasts, the measured data cover the full three month, i.e. from 1st January, with 10 minute resolution. For the Risoe site NWP results of the HIRLAM code from Danish Meteorological Institute were once stored for two thirds of a year, i.e. 1017 times analysis and 1 to 5 hour forecast within the period 21st October 1998 to 30th September 1999, and 10 minute averaged measured data are available since November 1995. (author)

  2. Reduction reaction analysis of nanoparticle copper oxide for copper direct bonding using formic acid

    Science.gov (United States)

    Fujino, Masahisa; Akaike, Masatake; Matsuoka, Naoya; Suga, Tadatomo

    2017-04-01

    Copper direct bonding is required for electronics devices, especially power devices, and copper direct bonding using formic acid is expected to lower the bonding temperature. In this research, we analyzed the reduction reaction of copper oxide using formic acid with a Pt catalyst by electron spin resonance analysis and thermal gravimetry analysis. It was found that formic acid was decomposed and radicals were generated under 200 °C. The amount of radicals generated was increased by adding the Pt catalyst. Because of these radicals, both copper(I) oxide and copper(II) oxide start to be decomposed below 200 °C, and the reduction of copper oxide is accelerated by reactants such as H2 and CO from the decomposition of formic acid above 200 °C. The Pt catalyst also accelerates the reaction of copper oxide reduction. Herewith, it is considered that the copper surface can be controlled more precisely by using formic acid to induce direct bonding.

  3. Comparison of Direct Solar Energy to Resistance Heating for Carbothermal Reduction of Regolith

    Science.gov (United States)

    Muscatello, Anthony C.; Gustafson, Robert J.

    2011-01-01

    A comparison of two methods of delivering thermal energy to regolith for the carbo thermal reduction process has been performed. The comparison concludes that electrical resistance heating is superior to direct solar energy via solar concentrators for the following reasons: (1) the resistance heating method can process approximately 12 times as much regolith using the same amount of thermal energy as the direct solar energy method because of superior thermal insulation; (2) the resistance heating method is more adaptable to nearer-term robotic exploration precursor missions because it does not require a solar concentrator system; (3) crucible-based methods are more easily adapted to separation of iron metal and glass by-products than direct solar energy because the melt can be poured directly after processing instead of being remelted; and (4) even with projected improvements in the mass of solar concentrators, projected photovoltaic system masses are expected to be even lower.

  4. A Novel Approach in Cinnamic Acid Synthesis: Direct Synthesis of Cinnamic Acids from Aromatic Aldehydes and Aliphatic Carboxylic Acids in the Presence of Boron Tribromide

    OpenAIRE

    Onciu, M.; Tanasa, F.; C. Chiriac

    2005-01-01

    Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP) and pyridine (Py) as bases and N-methyl-2-pyrolidinone (NMP) as solvent, at reflux (180-190°C) for 8-12 hours.

  5. Metabolically inert perfluorinated fatty acids directly activate uncoupling protein 1 in brown-fat mitochondria

    OpenAIRE

    Shabalina, Irina G.; Kalinovich, Anastasia V.; Cannon, Barbara; Nedergaard, Jan

    2015-01-01

    The metabolically inert perfluorinated fatty acids perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) can display fatty acid-like activity in biological systems. The uncoupling protein 1 (UCP1) in brown adipose tissue is physiologically (re)activated by fatty acids, including octanoate. This leads to bioenergetically uncoupled energy dissipation (heat production, thermogenesis). We have examined here the possibility that PFOA/PFOS can directly (re)activate UCP1 in isolated mouse b...

  6. A direct method for the synthesis of orthogonally protected furyl- and thienyl- amino acids.

    Science.gov (United States)

    Hudson, Alex S; Caron, Laurent; Colgin, Neil; Cobb, Steven L

    2015-04-01

    The synthesis of unnatural amino acids plays a key part in expanding the potential application of peptide-based drugs and in the total synthesis of peptide natural products. Herein, we report a direct method for the synthesis of orthogonally protected 5-membered heteroaromatic amino acids.

  7. Comparison of Direct Multiobjective Optimization Methods for the Design of Electric Vehicles

    OpenAIRE

    2006-01-01

    International audience; "System design oriented methodologies" are discussed in this paper through the comparison of multiobjective optimization methods applied to heterogeneous devices in electrical engineering. Avoiding criteria function derivatives, direct optimization algorithms are used. In particular, deterministic geometric methods such as the Hooke & Jeeves heuristic approach are compared with stochastic evolutionary algorithms (Pareto genetic algorithms). Different issues relative to...

  8. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  9. Toxicity induced by Basic Violet 14, Direct Red 28 and Acid Red 26 in zebrafish larvae.

    Science.gov (United States)

    Shen, Bing; Liu, Hong-Cui; Ou, Wen-Bin; Eilers, Grant; Zhou, Sheng-Mei; Meng, Fan-Guo; Li, Chun-Qi; Li, Yong-Quan

    2015-12-01

    Basic Violet 14, Direct Red 28 and Acid Red 26 are classified as carcinogenic dyes in the European textile ecology standard, despite insufficient toxicity data. In this study, the toxicity of these dyes was assessed in a zebrafish model, and the underlying toxic mechanisms were investigated. Basic Violet 14 and Direct Red 28 showed acute toxicity with a LC50 value at 60.63 and 476.84 µg ml(-1) , respectively, whereas the LC50 of Acid Red 26 was between 2500 and 2800 µg ml(-1) . Treatment with Basic Violet 14, Direct Red 28 and Acid Red 26 resulted in common developmental abnormalities including delayed yolk sac absorption and swimming bladder deflation. Hepatotoxicity was observed in zebrafish treated with Basic Violet 14, and cardiovascular toxicity was found in zebrafish treated with Acid Red 26 at concentrations higher than 2500 µg ml(-1) . Basic Violet 14 also caused significant up-regulation of GCLC gene expression in a dose-dependent manner whereas Acid Red 26 induced significant up-regulation of NKX2.5 and down-regulation of GATA4 at a high concentration in a dose-dependent manner. These results suggest that Basic Violet 14, Direct Red 28 and Acid Red 26 induce developmental and organ-specific toxicity, and oxidative stress may play a role in the hepatotoxicity of Basic Violet 14, the suppressed GATA4 expression may have a relation to the cardiovascular toxicity of Acid Red 26.

  10. RFLP analysis in rice by using ECL direct nucleic acid labeling and detection system

    Institute of Scientific and Technical Information of China (English)

    ZHANGShanhong; LIUBin; LUOLin; ZHUXiaoyuan; YANGQiyun; WUShangzhong

    1998-01-01

    ECL (Enhanced Chemiluminescence) direct nu cleic acid labeling and detection syslem were used for RFLP analysis in rice. The system involved directly labeling DNA probe with the enzyme horseradish peroxidase (HRP), and the detection of non-radioactive signal based on chemiluminescence, that was the generation of light via enzyme (HRP)-catalyzed reactions. It was a simple, safe,

  11. Folic acid food fortification-its history, effect, concerns, and future directions.

    Science.gov (United States)

    Crider, Krista S; Bailey, Lynn B; Berry, Robert J

    2011-03-01

    Periconceptional intake of folic acid is known to reduce a woman's risk of having an infant affected by a neural tube birth defect (NTD). National programs to mandate fortification of food with folic acid have reduced the prevalence of NTDs worldwide. Uncertainty surrounding possible unintended consequences has led to concerns about higher folic acid intake and food fortification programs. This uncertainty emphasizes the need to continually monitor fortification programs for accurate measures of their effect and the ability to address concerns as they arise. This review highlights the history, effect, concerns, and future directions of folic acid food fortification programs.

  12. COMPARISON OF OCCURENCE LACTIC ACID BACTERIA IN CHOSEN YOGURTS

    Directory of Open Access Journals (Sweden)

    Silvia Pinterová

    2010-11-01

    Full Text Available The yogurt is healthy food, which contains at least 100 million cultures per gram. Probiotic bacteria have been proven to reduce the effects of some gastrointestinal problems, probiotics can greatly reduce lactose intolerance, have also been proven to prevent colon cancers, there are also a natural immune system booster. In our research we detected numbers of lactid acid bacteria in yogurts in slovak market. There were classical yogurts, yogurts with probiotics, yogurts with fat and non fat. We numbered lactid acid bacteria from and after expiration, in agars MRS and Lee´s. In examined yogurts we detected from expiration from 78.107  to 169.107  and after expiration from 59.107 to 133.107 lactic acid bacteria in 1 ml of yogurt. In agreement with Food Codex of SR (2010 of rules all these yogurts satisfy number of lactid acid bacteria. doi:10.5219/31

  13. Comparison of amino acids interaction with gold nanoparticle.

    Science.gov (United States)

    Ramezani, Fatemeh; Amanlou, Massoud; Rafii-Tabar, Hashem

    2014-04-01

    The study of nanomaterial/biomolecule interface is an important emerging field in bionanoscience, and additionally in many biological processes such as hard-tissue growth and cell-surface adhesion. To have a deeper understanding of the amino acids/gold nanoparticle assemblies, the adsorption of these amino acids on the gold nanoparticles (GNPs) has been investigated via molecular dynamics simulation. In these simulations, all the constituent atoms of the nanoparticles were considered to be dynamic. The geometries of amino acids, when adsorbed on the nanoparticle, were studied and their flexibilities were compared with one another. The interaction of each of 20 amino acids was considered with 3 and 8 nm gold GNPs.

  14. Refractometric sensing using propagating versus localized surface plasmons: a direct comparison.

    Science.gov (United States)

    Svedendahl, Mikael; Chen, Si; Dmitriev, Alexandre; Käll, Mikael

    2009-12-01

    We present a direct experimental comparison between the refractive index sensing capabilities of localized surface plasmon resonances (LSPRs) in gold nanodisks and propagating surface plasmon resonances (SPRs) on 50 nm gold films. The comparison is made using identical experimental conditions, and for the same resonance wavelength, lambda(SP) congruent with 700 nm. Biosensing experiments with biotin-avidin coupling reveal that the two sensing platforms have very similar performance, despite a superior bulk refractive index sensing figure of merit for the SPR sensor. The results demonstrate that LSPR sensing based on simple transmission or reflection measurements is a highly competitive technique compared to the traditional SPR sensor.

  15. Influence of bi modification of pt anode catalyst in direct formic acid fuel cells.

    Science.gov (United States)

    Kang, Sungjin; Lee, Jaeyoung; Lee, Jae Kwang; Chung, Seung-Young; Tak, Yongsug

    2006-04-13

    The influence of Bi modification of Pt anode catalyst on the performance of direct formic acid fuel cells was investigated. Compared with the unmodified Pt anode, the Bi modified Pt (PtBi(m)) electrode prepared by under-potential deposition (UPD) caused faster electrocatalytic oxidation of formic acid at the same value of the overpotential, and thus, PtBi(m) resulted in an increase in the power performance of direct formic acid fuel cells. Electrochemical impedance spectra helped to explain the difference of performance between the unmodified Pt and Bi modified Pt electrodes. Solution conductivity and dehydration phenomena occurring in highly concentrated formic acid solutions can also explain the higher power performance of PtBi(m).

  16. A Novel Approach in Cinnamic Acid Synthesis: Direct Synthesis of Cinnamic Acids from Aromatic Aldehydes and Aliphatic Carboxylic Acids in the Presence of Boron Tribromide

    Directory of Open Access Journals (Sweden)

    M. Onciu

    2005-02-01

    Full Text Available Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP and pyridine (Py as bases and N-methyl-2-pyrolidinone (NMP as solvent, at reflux (180-190°C for 8-12 hours.

  17. A Copper-Assisted Palladium(II)-catalyzed Direct Arylation of Cyclic Enaminones with Arylboronic Acids

    OpenAIRE

    Kim, Yong Wook; Niphakis, Micah J.; Georg, Gunda I.

    2012-01-01

    Described herein is a palladium(II)-catalyzed direct arylation of cyclic enaminones with arylboronic acids. The versatility of this method is that both electron-rich and electron-poor boronic acids can be coupled in high yields. A mixture of two Cu(II) additives was crucial for efficient cross-coupling. The role of each Cu(II) reagent appears to be distinct and complementary serving to assist catalyst reoxidation and transmetallation through a putative arylcopper intermediate.

  18. Comparison of direct-drive and geared generator concepts for wind turbines.

    OpenAIRE

    2006-01-01

    The objective of this paper is to compare five different generator systems for wind turbines, namely the doubly-fed induction generator with three-stage gearbox (DFIG3G), the direct-drive synchronous generator with electrical excitation (DDSG), the direct-drive permanent-megnet generator (DDPMG), the permanent-magnet generator with single stage gearbox (PMG1G), and the doubly-fed induction generator with single-stage gearbox (DFIG1G). The comparison is based on cost and annual energy yield fo...

  19. Comparison of natural adsorbents for metal removal from acidic effluent.

    Science.gov (United States)

    Blais, J F; Shen, S; Meunier, N; Tyagi, R D

    2003-02-01

    Adsorption tests were carried out in acidic synthetic solutions (pH 2.0) using 20 g l(-1) of various natural adsorbents and 0.25 mM of 11 different metals. In decreasing order, the most efficient adsorbents tested were: oyster shells, cedar bark, vermiculite, cocoa shells and peanut shells. In contrast, weak metal adsorption was demonstrated by: red cedar wood, peat moss, pine wood, corn cobs and perlite. Metal adsorption capacities in acidic synthetic solution followed the order: Pb2+> Cr3+> Cu2+> Fe2+> Al3+> Ni2+> Cd2+ > Mn2+ > Zn2+ > Ca2+, Mg2+. Alkaline treatment (0.75 M NaOH) increased the effectiveness of metal removal for the majority of adsorbents. In contrast, acid treatment (0.75 M H2SO4) either reduced or did not affect the adsorption capacity of the materials tested. Finally, oyster shells, red cedar wood, vermiculite, cocoa shells and peanut shells, were effective natural adsorbents for the selective recovery of lead and trivalent chromium from acidic effluent.

  20. Complexation of NpO2+ with N-methyl-iminodiacetic Acid: in Comparison with Iminodiacetic and Dipicolinic Acids

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Guoxin; Rao, Linfeng

    2010-10-01

    Complexation of Np(V) with N-methyl-iminodiacetic acid (MIDA) in 1 M NaClO{sub 4} solution was studied with multiple techniques including potentiometry, spectrophotometry, and microcalorimetry. The 1:2 complex, NpO{sub 2}(MIDA){sub 2}{sup 3-} was identified for the first time in aqueous solution. The correlation between its optical absorption properties and symmetry was discussed, in comparison with Np(V) complexes with two structurally related nitrilo-dicarboxylic acids, iminodiacetic acid (IDA) and dipicolinic acid (DPA). The order of the binding strength (DPA > MIDA > IDA) is explained by the difference in the structural and electronic properties of the ligands. In general, the nitrilo-dicarboxylates form stronger complexes with Np(V) than oxy-dicarboxylates due to a much more favorable enthalpy of complexation.

  1. Direct visualization of retinoic acid in the rat hypothalamus: an immunohistochemical study.

    Science.gov (United States)

    Mangas, A; Bodet, D; Duleu, S; Yajeya, J; Geffard, M; Coveñas, R

    2012-02-10

    In order to increase our knowledge about the distribution of vitamins in the mammalian brain, we have developed a highly specific antiserum directed against retinoic acid with good affinity (10(-8) M), as evaluated by ELISA tests. In the rat brain, no immunoreactive fibers containing retinoic acid were detected. Cell bodies containing retinoic acid were only found in the hypothalamus. This work reports the first visualization and the morphological characteristics of cell bodies containing retinoic acid in the mammalian paraventricular hypothalamic nucleus and in the dorsal perifornical region, using an indirect immunoperoxidase technique. The restricted distribution of retinoic acid in the rat brain suggests that this vitamin could be involved in very specific physiological mechanisms.

  2. Determination of urinary vanillylmandelic acid by direct injection and coupled-column chromatography with electrochemical detection.

    Science.gov (United States)

    Eriksson, B M; Persson, B A; Wikström, M

    1990-04-27

    An automated column-switching system for determination of vanillylmandelic acid in urine is described. The liquid chromatographic system was composed of two separation columns with different selectivity properties, an octadecyl column coated with tributyl phosphate as stationary liquid phase and a silica-based anion exchanger. Urine samples were injected directly onto the first column, where vanillylmandelic acid was separated from the main part of the sample matrix. The internal standard isovanillylmandelic acid was co-eluting with vanillylmandelic acid, and a fraction of the eluate containing both substances was switched to the second column, where separation was performed. To assess peak purity, detection was performed with dual working electrodes in parallel mode. A relative standard deviation of 3.5% was obtained for determination of human urine samples containing 3 microM vanillylmandelic acid, and less than 0.1 microM could be detected.

  3. Direct measurement of homovanillic, vanillylmandelic and 5-hydroxyindoleacetic acids in urine by capillary electrophoresis.

    Science.gov (United States)

    García, A; Heinänen, M; Jiménez, L M; Barbas, C

    2000-02-25

    Separation conditions in CE, with a neutral coated capillary and reversed polarity, have been optimised to make direct measurement of vanillylmandelic acid, homovanillic acid and 5-hydroxyindoleacetic acid possible in urine samples without pre-treatment. The method developed has been validated, presenting adequate parameters for linearity, accuracy and precision. Detection limits range from 0.03 to 2.5 microM. Finally the method has been applied to urine samples taken from patients, both adults and children, in hospital. Some of them were also measured by immunoassay and HPLC-electrochemical detection and results have been compared.

  4. Mimicking the Nanostructure of Bone: Comparison of Polymeric Process-Directing Agents

    Directory of Open Access Journals (Sweden)

    Laurie B. Gower

    2010-12-01

    Full Text Available The nanostructure of bone has been replicated using a polymer-induced liquid-precursor (PILP mineralization process. This polymer-mediated crystallization process yields intrafibrillar mineralization of collagen with uniaxially-oriented hydroxyapatite crystals. The process-directing agent, an anionic polymer which we propose mimics the acidic non-collagenous proteins associated with bone formation, sequesters calcium and phosphate ions to form amorphous precursor droplets that can infiltrate the interstices of collagen fibrils. In search of a polymeric agent that produces the highest mineral content in the shortest time, we have studied the influence of various acidic polymers on the in vitro mineralization of collagen scaffolds via the PILP process. Among the polymers investigated were poly-L-aspartic acid (PASP, poly-L-glutamic acid (PGLU, polyvinylphosphonic acid (PVPA, and polyacrylic acid (PAA. Our data indicate that PASP and the combination of PGLU/PASP formed stable mineralization solutions, and yielded nano-structured composites with the highest mineral content. Such studies contribute to our goal of preparing biomimetic bone graft substitutes with composition and structure that mimic bone.

  5. Direct lactic acid fermentation of Jerusalem artichoke tuber extract using Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis.

    Science.gov (United States)

    Choi, Hwa-Young; Ryu, Hee-Kyoung; Park, Kyung-Min; Lee, Eun Gyo; Lee, Hongweon; Kim, Seon-Won; Choi, Eui-Sung

    2012-06-01

    Lactic acid fermentation of Jerusalem artichoke tuber was performed with strains of Lactobacillus paracasei without acidic or enzymatic inulin hydrolysis prior to fermentation. Some strains of L. paracasei, notably KCTC13090 and KCTC13169, could ferment hot-water extract of Jerusalem artichoke tuber more efficiently compared with other Lactobacillus spp. such as L. casei type strain KCTC3109. The L. paracasei strains could utilize almost completely the fructo-oligosaccharides present in Jerusalem artichoke. Inulin-fermenting L. paracasei strains produced c.a. six times more lactic acid compared with L. casei KCTC3109. Direct lactic fermentation of Jerusalem artichoke tuber extract at 111.6g/L of sugar content with a supplement of 5 g/L of yeast extract by L. paracasei KCTC13169 in a 5L jar fermentor produced 92.5 ce:hsp sp="0.25"/>g/L of lactic acid with 16.8 g/L fructose equivalent remained unutilized in 72 h. The conversion efficiency of inulin-type sugars to lactic acid was 98% of the theoretical yield.

  6. Direct transformation of carbohydrates to the biofuel 5-ethoxymethylfurfural by solid acid catalysts

    DEFF Research Database (Denmark)

    Li, Hu; Shunmugavel, Saravanamurugan; Yang, Song;

    2016-01-01

    The direct conversion of glucose to 5-ethoxymethylfurfural (EMF) is a promising biomass transformation due to the products potential application as a biofuel. Here, the conversion of glucose to EMF was examined over several solid acid catalysts in ethanol between 96 and 125 oC. Among the catalyst...

  7. Comparison of D-gluconic acid production in selected strains of acetic acid bacteria.

    Science.gov (United States)

    Sainz, F; Navarro, D; Mateo, E; Torija, M J; Mas, A

    2016-04-01

    The oxidative metabolism of acetic acid bacteria (AAB) can be exploited for the production of several compounds, including D-gluconic acid. The production of D-gluconic acid in fermented beverages could be useful for the development of new products without glucose. In the present study, we analyzed nineteen strains belonging to eight different species of AAB to select those that could produce D-gluconic acid from D-glucose without consuming D-fructose. We tested their performance in three different media and analyzed the changes in the levels of D-glucose, D-fructose, D-gluconic acid and the derived gluconates. D-Glucose and D-fructose consumption and D-gluconic acid production were heavily dependent on the strain and the media. The most suitable strains for our purpose were Gluconobacter japonicus CECT 8443 and Gluconobacter oxydans Po5. The strawberry isolate Acetobacter malorum (CECT 7749) also produced D-gluconic acid; however, it further oxidized D-gluconic acid to keto-D-gluconates.

  8. Brønsted Acid-Catalyzed Direct Substitution of 2-Ethoxytetrahydrofuran with Trifluoroborate Salts

    Directory of Open Access Journals (Sweden)

    Kayla M. Fisher

    2016-06-01

    Full Text Available Metal-free transformations of organotrifluoroborates are advantageous since they avoid the use of frequently expensive and sensitive transition metals. Lewis acid-catalyzed reactions involving potassium trifluoroborate salts have emerged as an alternative to metal-catalyzed protocols. However, the drawbacks to these methods are that they rely on the generation of unstable boron dihalide species, thereby resulting in low functional group tolerance. Recently, we discovered that in the presence of a Brønsted acid, trifluoroborate salts react rapidly with in situ generated oxocarbenium ions. Here, we report Brønsted acid-catalyzed direct substitution of 2-ethoxytetrahydrofuran using potassium trifluoroborate salts. The reaction occurs when tetrafluoroboric acid is used as a catalyst to afford functionalized furans in moderate to excellent yields. A variety of alkenyl- and alkynyltrifluoroborate salts readily participate in this transformation.

  9. Direct melting polycondensation and characterization of poly(ε-caprolactone-co-lactic acid)

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yaoming; ZHOU Ling; WANG Zhaoyang

    2007-01-01

    A kind of biodegradable material,poly(ε-caprolactone-co-lactic acid) [P(CL-co-LA)] was synthesized via the direct melting polycondensation of lactic acid (LA)and ε-caprolactone (CL).The influences of the polycondensation time,and the catalyst type on the intrinsic viscosity of P(CL-co-LA) were also investigated.The results indicate that P(CL-co-dl-LA),with an intrinsic viscosity of 0.4733 dL/g,can be prepared by direct melting polycondensation with the molar ratio LA/CL = 3:7 at 180℃ and 70 Pa for 12 h,using 0.5% (mass fraction) of SnCI2 as the catalyst.Compared with lactide ring-opening polycondensation (ROP),the direct melting polycondensation of LA and CL is more practicable and simple.

  10. Comparison of methods of extracting messenger Ribonucleic Acid from ejaculated Porcine (Sus Scrofa) Spermatozoa

    Science.gov (United States)

    H. D. Guthrie, G.R. Welch, and L. A. Blomberg. Comparison of Methods of Extracting Messenger Ribonucleic Acid from Ejaculated Porcine (Sus Scrofa) Spermatozoa. Biotechnology and Germplasm Laboratory, Agricultural Research Service U. S. Department of Agriculture, Beltsville, MD 20705 The purpos...

  11. Coral calcification under environmental change: a direct comparison of the alkalinity anomaly and buoyant weight techniques

    Science.gov (United States)

    Schoepf, Verena; Hu, Xinping; Holcomb, Michael; Cai, Wei-Jun; Li, Qian; Wang, Yongchen; Xu, Hui; Warner, Mark E.; Melman, Todd F.; Hoadley, Kenneth D.; Pettay, D. Tye; Matsui, Yohei; Baumann, Justin H.; Grottoli, Andréa G.

    2017-03-01

    Two primary methods—the buoyant weight (BW) and alkalinity anomaly (AA) techniques—are currently used to quantify net calcification rates ( G) in scleractinian corals. However, it remains unclear whether they are directly comparable since the few method comparisons conducted to date have produced inconsistent results. Further, such a comparison has not been made for tropical corals. We directly compared G BW and G AA in four tropical and one temperate coral species cultured under various pCO2, temperature, and nutrient conditions. A range of protocols for conducting alkalinity depletion incubations was assessed. For the tropical corals, open-top incubations with manual stirring produced G AA that were highly correlated with and not significantly different from G BW. Similarly, G AA of the temperate coral was not significantly different from G BW when incubations provided water motion using a pump, but were significantly lower than G BW by 16% when water motion was primarily created by aeration. This shows that the two techniques can produce comparable calcification rates in corals but only when alkalinity depletion incubations are conducted under specific conditions. General recommendations for incubation protocols are made, especially regarding adequate water motion and incubation times. Further, the re-analysis of published data highlights the importance of using appropriate regression statistics when both variables are random and measured with error. Overall, we recommend the AA technique for investigations of community and short-term day versus night calcification, and the BW technique to measure organism calcification rates integrated over longer timescales due to practical limitations of both methods. Our findings will facilitate the direct comparison of studies measuring coral calcification using either method and thus have important implications for the fields of ocean acidification research and coral biology in general.

  12. A direct comparison of protein structure in the gas and solution phase: the Trp-cage

    DEFF Research Database (Denmark)

    Patriksson, Alexandra; Adams, Christopher M; Kjeldsen, Frank;

    2007-01-01

    Molecular dynamics simulations of zwitterions of the Trp-cage protein in the gas phase show that the most stable ion in vacuo has preserved the charge locations acquired in solution. A direct comparison of the gas and solution-phase structures reveals that, despite the similarity in charge location......, there is significant difference in the structures, with a substantial increase in hydrogen bonds and exposure of hydrophobic parts in the gas phase. The structure of the salt bridge in the gas phase is also much more stable than in the (experimental) solution structure....

  13. Direct electrospray ionization mass spectrometry quantitative analysis of sebacic and terephthalic acids in biodegradable polymers.

    Science.gov (United States)

    Rizzarelli, Paola; Zampino, Daniela; Ferreri, Loredana; Impallomeni, Giuseppe

    2011-02-01

    A direct, rapid, and easy electrospray ionization mass spectrometry (ESI-MS) method to determine concentrations of sebacic acid (SA) and terephthalic acid (TA) residues in biodegradable copolymers was developed. Copolyester samples were synthesized from 1,4-butanediol and sebacic and terephthalic acids by melt polymerization. Extraction of monomers was performed in methanol. Their concentrations were determined by direct infusion ESI-MS, without chromatographic separation, using 1,12-dodecanedioic acid (DDA) as an internal standard. Calibration curves were obtained by plotting the ratio of the areas of the peaks relative to monomers and DDA standard as a function of their concentration ratio. We validated the method by determining the concentration of TA residue using both the ESI-MS protocol and high-performance liquid chromatography (HPLC) analysis with UV detection. The linearity range and the detection limit of this assay were 0.1-5.0 and 0.01 ppm for SA and 0.1-6.0 and 0.03 ppm for TA. This assay represents a useful alternative to conventional methods currently employed for acid quantification, resulting advantageous for its speed and high sensitivity.

  14. Comparison between phosphoric acid and hydrochloric acid in microabrasion technique for the treatment of dental fluorosis

    OpenAIRE

    Mahshid Mohammadi Bassir; Golnaz Bagheri

    2013-01-01

    Purpose: To compare the effectiveness of phosphoric acid (H 3 PO 4 )-pumice compound with conventional hydrochloric acid (HCl)-pumice compound in treating different severities of dental fluorosis with the microabrasion technique. Materials and Methods: Sixty-seven anterior teeth from seven patients with different severities of dental fluorosis were treated. In each patient, half of the teeth were treated with HCl-pumice compound and the other half with H 3 PO 4 -pumice compound (split-mou...

  15. Label-free direct surface-enhanced Raman scattering (SERS) of nucleic acids (Conference Presentation)

    Science.gov (United States)

    Guerrini, Luca; Morla-Folch, Judit; Gisbert-Quilis, Patricia; Xie, Hainan; Alvarez-Puebla, Ramon

    2016-03-01

    Recently, plasmonic-based biosensing has experienced an unprecedented level of attention, with a particular focus on the nucleic acid detection, offering efficient solutions to engineer simple, fast, highly sensitive sensing platforms while overcoming important limitations of PCR and microarray techniques. In the broad field of plasmonics, surface-enhanced Raman scattering (SERS) spectroscopy has arisen as a powerful analytical tool for detection and structural characterization of biomolecules. Today applications of SERS to nucleic acid analysis largely rely on indirect strategies, which have been demonstrated very effective for pure sensing purposes but completely dismiss the exquisite structural information provided by the direct acquisition of the biomolecular vibrational fingerprint. Contrarily, direct label-free SERS of nucleic acid shows an outstanding potential in terms of chemical-specific information which, however, remained largely unexpressed mainly because of the inherent poor spectral reproducibility and/or limited sensitivity. To address these limitations, we developed a fast and affordable high-throughput screening direct SERS method for gaining detailed genomic information on nucleic acids (DNA and RNA) and for the characterization and quantitative recognition of DNA interactions with exogenous agents. The simple strategy relies on the electrostatic adhesion of DNA/RNA onto positively-charged silver colloids that promotes the nanoparticle aggregation into stable clusters yielding intense and reproducible SERS spectra at picogram level (i.e. the analysis can be performed without the necessity of amplification steps thus providing realistic direct information of the nucleic acid in its native state). We anticipate this method to gain a vast impact and set of applications in different fields, including medical diagnostics, genomic screening, drug discovery, forensic science and even molecular electronics.

  16. Thioarsenides: A case for long-range Lewis acid-base-directed van der Waals interactions

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Gerald V.; Wallace, Adam F.; Downs, R. T.; Ross, Nancy L.; Cox, David F.; Rosso, Kevin M.

    2011-04-01

    Electron density distributions, bond paths, Laplacian and local energy density properties have been calculated for a number of As4Sn (n = 3,4,5) thioarsenide molecular crystals. On the basis of the distributions, the intramolecular As-S and As-As interactions classify as shared bonded interactions and the intermolecular As-S, As-As and S-S interactions classify as closed-shell van der Waals bonded interactions. The bulk of the intermolecular As-S bond paths link regions of locally concentrated electron density (Lewis base regions) with aligned regions of locally depleted electron density (Lewis acid regions) on adjacent molecules. The paths are comparable with intermolecular paths reported for several other molecular crystals that link aligned Lewis base and acid regions in a key-lock fashion, interactions that classified as long range Lewis acid-base directed van der Waals interactions. As the bulk of the intermolecular As-S bond paths (~70%) link Lewis acid-base regions on adjacent molecules, it appears that molecules adopt an arrangement that maximizes the number of As-S Lewis acid-base intermolecular bonded interactions. The maximization of the number of Lewis acid-base interactions appears to be connected with the close-packed array adopted by molecules: distorted cubic close-packed arrays are adopted for alacránite, pararealgar, uzonite, realgar and β-AsS and the distorted hexagonal close-packed arrays adopted by α- and β-dimorphite. A growth mechanism is proposed for thioarsenide molecular crystals from aqueous species that maximizes the number of long range Lewis acid-base vdW As-S bonded interactions with the resulting directed bond paths structuralizing the molecules as a molecular crystal.

  17. Comparison of Direct Normal Irradiance Derived from Silicon and Thermopile Global Hemispherical Radiation Detectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Myers, D. R.

    2010-01-01

    Concentrating solar applications utilize direct normal irradiance (DNI) radiation, a measurement rarely available. The solar concentrator industry has begun to deploy numerous measurement stations to prospect for suitable system deployment sites. Rotating shadowband radiometers (RSR) using silicon photodiodes as detectors are typically deployed. This paper compares direct beam estimates from RSR to a total hemispherical measuring radiometer (SPN1) multiple fast thermopiles. These detectors simultaneously measure total and diffuse radiation from which DNI can be computed. Both the SPN1 and RSR-derived DNI are compared to DNI measured with thermopile pyrheliometers. Our comparison shows that the SPN1 radiometer DNI estimated uncertainty is somewhat greater than, and on the same order as, the RSR DNI estimates for DNI magnitudes useful to concentrator technologies.

  18. Rh(III)-catalyzed decarboxylative ortho-heteroarylation of aromatic carboxylic acids by using the carboxylic acid as a traceless directing group.

    Science.gov (United States)

    Qin, Xurong; Sun, Denan; You, Qiulin; Cheng, Yangyang; Lan, Jingbo; You, Jingsong

    2015-04-03

    Highly selective decarboxylative ortho-heteroarylation of aromatic carboxylic acids with various heteroarenes has been developed through Rh(III)-catalyzed two-fold C-H activation, which exhibits a wide substrate scope of both aromatic carboxylic acids and heteroarenes. The use of naturally occurring carboxylic acid as the directing group avoids troublesome extra steps for installation and removal of an external directing group.

  19. Comparison the effectiveness of pyruvic acid 50% and salicylic acid 30% in the treatment of acne

    Directory of Open Access Journals (Sweden)

    Fariba Jaffary

    2016-01-01

    Full Text Available Background: Acne vulgaris is a chronic inflammatory disease of the pilosebaceous follicles and one of the most common skin diseases. The peeling method has been recently found to be effective for acne treatment. This study aimed to compare the efficacy of pyruvic acid 50% and salicylic acid 30% peeling in the treatment of mild to moderate acne. Materials and Methods: In a prospective single-blinded clinical trial, 86 patients with acne were randomly assigned into two groups. In both groups, the routine treatment of acne (topical solution of erythromycin 4%, triclorocarban soap, and sunscreen were used twice a day for 8 weeks. In addition, salicylic acid 30% for the control group and pyruvic acid 50% for the case group were used. In both groups, acne severity index (ASI was calculated before and at week 2, 4, 6, and 8 of the treatment. Patient satisfaction was assessed at the end of the treatment. Side effects were recorded using a checklist. Results: In both groups, the reduction in the number of comedones, papules, and ASI were statistically significant (P < 0.001 in the course of treatment. However, it was not significant regarding the number of pustules (P = 0.09. None of the number of comedone, papules, pustules, and ASI was statistically different between study groups. Both treatment groups had similar side effects except for scaling in the fifth session, which was significantly lower in salicylic acid - treated patients (P = 0.015. Conclusion: Both pyruvic acid 50% and salicylic acid 30% are effective in the improvement of mild to moderate acne with no significant difference in efficacy and side effects.

  20. All-optical link for direct comparison of distant optical clocks

    CERN Document Server

    Fujieda, Miho; Nagano, Shigeo; Yamaguchi, Atsushi; Hachisu, Hidekazu; Ido, Tetsuya

    2011-01-01

    We developed an all-optical link system for making remote comparisons of two distant ultra-stable optical clocks. An optical carrier transfer system based on a fiber interferometer was employed to compensate the phase noise accumulated during the propagation through a fiber link. Transfer stabilities of $2\\times10^{-15}$ at 1 second and $4\\times10^{-18}$ at 1000 seconds were achieved in a 90-km link. An active polarization control system was additionally introduced to maintain the transmitted light in an adequate polarization, and consequently, a stable and reliable comparison was accomplished. The instabilities of the all-optical link system, including those of the erbium doped fiber amplifiers (EDFAs) which are free from phase-noise compensation, were below $2\\times10^{-15}$ at 1 second and $7\\times10^{-17}$ at 1000 seconds. The system was available for the direct comparison of two distant $^{87}$Sr lattice clocks via an urban fiber link of 60 km. This technique will be essential for the measuring the repro...

  1. A Direct Comparison of HI and Lyα Morphologies in Two LARS Galaxies

    Science.gov (United States)

    Fitzgibbon, Kathleen; Cannon, John M.; Freeland, Emily; Hayes, Matthew; Östlin, Göran; LARS Team

    2016-01-01

    The Lyman-Alpha Reference Sample (LARS) and its extension (eLARS) represent an exhaustive campaign to reverse-engineer galaxies. The main goal is to understand how Lyα is transported within galaxies: what fraction of it escapes, and what physical properties affect Lyα morphology and radiative transport (e.g. dust and gas content, metallicity, kinematics, properties of the stellar population). Neutral hydrogen emission, which can be used to determine a galaxy's structure and kinematics, was observed using the B and C configurations of the Very Large Array in two galaxies from the sample: LARS02 and LARS09. Images of the HI mass surface density and of the intensity weighted HI velocity field were created at angular scales of ~8 arcseconds. Extended HI gas is detected at high significance up to ˜30 kpc from the optical body of LARS02. LARS09 has a severely disturbed optical morphology; our new HI observations reveal that LARS09 is interacting with the nearby field galaxy SDSS J082353.65+280622.2. In combination with direct imaging of the Lyα morphology from the Hubble Space Telescope, this program has produced the first direct comparison of Lyα and HI morphologies. These observations demonstrate concept for a significant observational campaign that will produce similar comparisons in the remaining 40 LARS+eLARS galaxies.KF was partially supported by a Science Education Award from the Howard Hughes Medical Institute (HHMI) to Macalester College.

  2. Direct Comparison of Møller and Compton Polarimeters in Hall C at Jefferson Lab

    Science.gov (United States)

    Gaskell, Dave

    2017-01-01

    Knowledge of the electron beam polarization is one of the most important systematic uncertainties in precision, parity-violating electron scattering experiments with next generation experiments aiming to measure the electron beam polarization to better than 0.5%. At high energies, the most typical polarimetry techniques are Møller (polarized electron-electron) and Compton (polarized electron-photon) scattering. The use of two techniques with different systematic uncertainties provides confidence in the extracted beam polarization. Direct comparisons of the two polarimetry techniques are challenging in that Compton polarimeters typically desire maximum beam flux (high beam currents) while Møller polarimeters need to limit the beam current to avoid depolarization effects in the target. We have performed a direct comparison of the Møller and Compton polarimeters in experimental Hall C at Jefferson Lab. This test is unique in that the data were taken sequentially under identical beam conditions at 4.5 μA. We found excellent agreement between the Hall C Møller and Compton polarimeters. Combined with high-current Compton data, we were also able to limit the beam current dependence of the beam polarization to 1% or less up to a beam current of 180 μA. Supported in part by the U.S. Deparment of Energy, contract number AC05-06OR23177, under which Jefferson Science Associates, LLC operates Thomas Jefferson National Accelerator Facility.

  3. Multiple number and letter comparison: directionality and accessibility in numeric and alphabetic memories.

    Science.gov (United States)

    Jou, Jerwen

    2003-01-01

    In 3 experiments, subjects made comparativejudgments on a set of 2 numbers or letters, 3 numbers or letters, or 5 numbers or letters. Numeric and alphabetic serial order memories were contrasted. Three aspects of serial order memory processes were identified: computational complexity, directionality, and accessibility. Computational complexity is the number of algorithmic steps involved in identifying a target. Directional bias is measured as the speed differences in identifying serial targets of equal computational complexity in a stimulus array. Memory accessibility is measured as the numeric and alphabetic serial position effects. Subjects had a slight directional bias favoring backward ordering for single digits but no bias in 2-digit number ordering, in contrast to a strong forward directional advantage in letter ordering. The speed of number access was found to steadily and evenly decrease along the numeric scale, in contrast to a systematic pattern of variations in alphabet access along the alphabetic scale. Finally, the middle item effect (the middle item in a multi-item array is identified most slowly) found in Jou's (1997) multiple-letter comparison study was generalized to numbers.

  4. Primary structure of rat secretory acid phosphatase and comparison to other acid phosphatases.

    Science.gov (United States)

    Roiko, K; Jänne, O A; Vihko, P

    1990-05-14

    Overlapping cDNA clones encoding rat prostatic acid phosphatase (rPAP) were isolated by using two human prostatic acid phosphatase (hPAP)-encoding cDNAs to screen rat prostatic cDNA libraries. The isolated cDNAs encompassed a total of 1626 nucleotides (nt), of which 1143 nt corresponded to the protein coding sequence encoding a mature polypeptide of 350 amino acids (aa) and a 31-aa long signal peptide-like sequence. The deduced Mr of the mature rPAP was 40,599. RNA blot analysis indicated the presence of three mRNA species (4.9, 2.3 and 1.5 kb in size) in the rat prostate. The deduced aa sequences of rPAP and hPAP show 75% identity, whereas the similarity between rPAP and human lysosomal acid phosphatase (hLAP) is only 45%. Furthermore, the sequence similarity between rPAP and rat lysosomal acid phosphatase (rLAP) is 46% at the aa level. Similar to hPAP, but unlike hLAP and rLAP, the rPAP sequence lacks a membrane-anchoring domain indicating the secretory character of this phosphatase. All six cysteines present in the overlapping areas of the mature rPAP, hPAP, rLAP and hLAP proteins are positionally conserved, suggesting that these residues are important for the tertiary structure of acid phosphatases (APs). The previously reported active site residues, two arginines and one histidine, are also conserved in these APs.

  5. Beware how you compare: comparison direction dictates stimulus-valence-modulated presentation-order effects in preference judgment.

    Science.gov (United States)

    Englund, Mats P; Hellström, Åke

    2013-07-01

    Englund and Hellström (Journal of Behavioral Decision Making 25:82-94, 2012a) found a tendency to prefer the left (first-read) of two attractive alternatives but the right (second-read) of two unattractive alternatives-a valence-dependent word-order effect (WOE). They used stimulus pairs spaced horizontally, and preference was indicated by choosing one of several written statements (e.g., "apple I like more than pear"). The results were interpreted as being due to stimulus position, with the magnitude of the left stimulus having a greater impact on the comparison outcome than the magnitude of the right. Here we investigated the effects of the positioning of the stimuli versus the semantics of the response alternatives (i.e., comparison direction) on the relative impacts of the stimuli. Participants rated preferences for stimuli spaced horizontally with the response alternatives not dictating a comparison direction (Exp. 1), and stimuli spaced vertically using Englund and Hellström's (Journal of Behavioral Decision Making 25:82-94, 2012a) response alternatives, which dictate a comparison direction semantically (Exp. 2). The results showed that the valence-dependent WOE found by Englund and Hellström (Journal of Behavioral Decision Making 25:82-94, 2012a) was not due to the horizontal stimulus positioning per se, but to the induced comparison direction, with the effect probably being mediated by attention directed at the subject of the comparison. We concluded that a set comparison direction is required for the valence-dependent WOE to appear, and that using Hellström's sensation-weighting model to determine stimulus weights is a way to verify the comparison direction.

  6. Comparison between direct and reverse electroporation of cells in situ: a simulation study.

    Science.gov (United States)

    Towhidi, Leila; Khodadadi, Delaram; Maimari, Nataly; Pedrigi, Ryan M; Ip, Henry; Kis, Zoltan; Kwak, Brenda R; Petrova, Tatiana W; Delorenzi, Mauro; Krams, Rob

    2016-03-01

    The discovery of the human genome has unveiled new fields of genomics, transcriptomics, and proteomics, which has produced paradigm shifts on how to study disease mechanisms, wherein a current central focus is the understanding of how gene signatures and gene networks interact within cells. These gene function studies require manipulating genes either through activation or inhibition, which can be achieved by temporarily permeabilizing the cell membrane through transfection to delivercDNAorRNAi. An efficient transfection technique is electroporation, which applies an optimized electric pulse to permeabilize the cells of interest. When the molecules are applied on top of seeded cells, it is called "direct" transfection and when the nucleic acids are printed on the substrate and the cells are seeded on top of them, it is termed "reverse" transfection. Direct transfection has been successfully applied in previous studies, whereas reverse transfection has recently gained more attention in the context of high-throughput experiments. Despite the emerging importance, studies comparing the efficiency of the two methods are lacking. In this study, a model for electroporation of cells in situ is developed to address this deficiency. The results indicate that reverse transfection is less efficient than direct transfection. However, the model also predicts that by increasing the concentration of deliverable molecules by a factor of 2 or increasing the applied voltage by 20%, reverse transfection can be approximately as efficient as direct transfection.

  7. Simulation of mixture microstructures via particle packing models and their direct comparison with real mixtures

    Science.gov (United States)

    Gulliver, Eric A.

    The objective of this thesis to identify and develop techniques providing direct comparison between simulated and real packed particle mixture microstructures containing submicron-sized particles. This entailed devising techniques for simulating powder mixtures, producing real mixtures with known powder characteristics, sectioning real mixtures, interrogating mixture cross-sections, evaluating and quantifying the mixture interrogation process and for comparing interrogation results between mixtures. A drop and roll-type particle-packing model was used to generate simulations of random mixtures. The simulated mixtures were then evaluated to establish that they were not segregated and free from gross defects. A powder processing protocol was established to provide real mixtures for direct comparison and for use in evaluating the simulation. The powder processing protocol was designed to minimize differences between measured particle size distributions and the particle size distributions in the mixture. A sectioning technique was developed that was capable of producing distortion free cross-sections of fine scale particulate mixtures. Tessellation analysis was used to interrogate mixture cross sections and statistical quality control charts were used to evaluate different types of tessellation analysis and to establish the importance of differences between simulated and real mixtures. The particle-packing program generated crescent shaped pores below large particles but realistic looking mixture microstructures otherwise. Focused ion beam milling was the only technique capable of sectioning particle compacts in a manner suitable for stereological analysis. Johnson-Mehl and Voronoi tessellation of the same cross-sections produced tessellation tiles with different the-area populations. Control charts analysis showed Johnson-Mehl tessellation measurements are superior to Voronoi tessellation measurements for detecting variations in mixture microstructure, such as altered

  8. Metabolically inert perfluorinated fatty acids directly activate uncoupling protein 1 in brown-fat mitochondria.

    Science.gov (United States)

    Shabalina, Irina G; Kalinovich, Anastasia V; Cannon, Barbara; Nedergaard, Jan

    2016-05-01

    The metabolically inert perfluorinated fatty acids perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) can display fatty acid-like activity in biological systems. The uncoupling protein 1 (UCP1) in brown adipose tissue is physiologically (re)activated by fatty acids, including octanoate. This leads to bioenergetically uncoupled energy dissipation (heat production, thermogenesis). We have examined here the possibility that PFOA/PFOS can directly (re)activate UCP1 in isolated mouse brown-fat mitochondria. In wild-type brown-fat mitochondria, PFOS and PFOA overcame GDP-inhibited thermogenesis, leading to increased oxygen consumption and dissipated membrane potential. The absence of this effect in brown-fat mitochondria from UCP1-ablated mice indicated that it occurred through activation of UCP1. A competitive type of inhibition by increased GDP concentrations indicated interaction with the same mechanistic site as that utilized by fatty acids. No effect was observed in heart mitochondria, i.e., in mitochondria without UCP1. The stimulatory effect of PFOA/PFOS was not secondary to non-specific mitochondrial membrane permeabilization or to ROS production. Thus, metabolic effects of perfluorinated fatty acids could include direct brown adipose tissue (UCP1) activation. The possibility that this may lead to unwarranted extra heat production and thus extra utilization of food resources, leading to decreased fitness in mammalian wildlife, is discussed, as well as possible negative effects in humans. However, a possibility to utilize PFOA-/PFOS-like substances for activating UCP1 therapeutically in obesity-prone humans may also be envisaged.

  9. Effect of L-ascorbic acid as additive for exhaust emission reduction in a direct injection diesel engine using mango seed methyl ester

    Directory of Open Access Journals (Sweden)

    Ramalingam Senthil

    2016-01-01

    Full Text Available In this present study the effect of L-ascorbic acid antioxidants additive for oxides of nitrogen emission reduction in a neat mango seed biodiesel fueled direct injection Diesel engine. The antioxidant additive L-ascorbic acid is tested on a Kirloskar-make four stroke water cooled single cylinder Diesel engine of 5.2 kW. There are four proportions of additive are used:1 ml, 2 ml, 3 ml, and 4 ml. Among the different additive proportion,4 ml concentration of L-ascorbic acid additive is optimal as oxides of nitrogen levels are substantially reduced up to 9% in the whole load range in comparison with neat biodiesel. However, hydrocarbon and carbonmonoxide emissions are found to have slightly increased by the addition of additive with biodiesel.

  10. A Direct Comparison of Two High Precision Relative Gravity Meters at Optimal Performance

    Science.gov (United States)

    van Westrum, D.

    2015-12-01

    NGS has maintained and operated GWR Superconducting Gravimeter #024 since 1995. It has been widely considered one of the most quiet instruments from that era. It was recently upgraded with state of the art electronics and its operating parameters reoptimzied. A Micro-g LaCoste gPhoneX, installed on a high precision tilt table, was collocated with the SG at the Table Mountain Geophysical Observatory near Boulder, CO and the two instruments operated side by side for approximately two months. Results in both the frequency domain and selected time series from large seismic signals (e.g. earthquakes) will be presented, allowing for a direct comparison between the instruments in identical, ideal conditions.

  11. Gaussian variational ansatz in the problem of anomalous sea waves: Comparison with direct numerical simulations

    CERN Document Server

    Ruban, V P

    2015-01-01

    The nonlinear dynamics of an obliquely oriented wave packet at sea surface is studied both analytically and numerically for various initial parameters of the packet, in connection with the problem of oceanic rogue waves. In the framework of Gaussian variational ansatz applied to the corresponding (1+2D) hyperbolic nonlinear Schr\\"odinger equation, a simplified Lagrangian system of differential equations is derived, which determines the evolution of coefficients of the real and imaginary quadratic forms appearing in the Gaussian. This model provides a semi-quantitative description for the process of nonlinear spatio-temporal focusing, which is one of the most probable mechanisms of rogue wave formation in random wave fields. The system is integrated in quadratures, which fact allows us to understand qualitative differences between the linear and nonlinear regimes of the focusing of wave packet. Comparison of the Gaussian model predictions with results of direct numerical simulation of fully nonlinear long-cres...

  12. When is a metric not a metric? Remarks on direct curve comparison in bioequivalence studies.

    Science.gov (United States)

    Jawień, Wojciech

    2009-06-01

    The majority of measures proposed to date for direct curve comparison in bioequivalence studies were investigated. These measures have often been called metrics, but in most cases this was incorrect in the mathematical sense. It was demonstrated, with a set of counter-examples, that the axioms of a metric are fulfilled only for the integral p-metric and some of its transforms. The Rescigno index and two other measures devised by Polli and McLean are the semi-metrics, lacking the triangle inequality, while others also lack symmetry. The use of the p-metric is therefore recommended, and statistical analysis is suggested as a point at which the scaling of differences might be carried out.

  13. Comparison of five directed graph measures for identification of leading interictal epileptic regions

    Science.gov (United States)

    Amini, Ladan; Jutten, Christian; Achard, Sophie; David, Olivier; Kahane, Philippe; Vercueil, Laurent; Minotti, Lorella; Hossein-Zadeh, Gh. Ali; Soltanian-Zadeh, Hamid

    2010-01-01

    Directed graphs (digraphs) derived from interictal periods of intracerebral EEG (iEEG) recordings can be used to estimate the leading interictal epileptic regions for presurgery evaluations. For this purpose, quantification of the emittance contribution of each node to the rest of digraph is important. However, the usual digraph measures are not very well suited for this quantification. Here we compare the efficiency of recently introduced local information measure LI and a new measure called total global efficiency with classical measures like global efficiency, local efficiency and node degree. For evaluation, the estimated leading interictal epileptic regions based on five measures are compared with seizure onset zones obtained by visual inspection of epileptologists for five patients. The comparison revealed the superior performance of LI measure. We showed efficiency of different digraph measures for the purpose of source and sink node identification. PMID:20952817

  14. Direct comparison of defect ensembles extracted from damage probability and raster scan measurements

    Energy Technology Data Exchange (ETDEWEB)

    Batavičiūtė, G., E-mail: gintare.bataviciute@ff.stud.vu.lt; Ščiuka, M.; Melninkaitis, A. [Laser Research Center, Vilnius University, Saulėtekio al. 10 LT-10223 Vilnius (Lithuania)

    2015-09-14

    The presented study addresses the characterization of nanometer sized defects acting as damage precursors in nanosecond laser pulse duration regime. Two approaches are used to extract distributions of localized damage precursors, namely, damage probability and damage density measurements. Testing is performed on uncoated and SiO{sub 2} monolayer film deposited fused silica substrate exposed with pulsed UV irradiation (355 nm, 4.8 ns). Then, a direct comparison of damage precursor ensembles obtained from both methods is carried out. Our analysis indicates apparent differences between both methods that are discussed in detail. Contamination by ablation products is identified as one of the key factors that influence damage density measurements.

  15. Comparison of video and direct observation methods for measuring oral behaviour in veal calves

    Directory of Open Access Journals (Sweden)

    Marina Verga

    2010-01-01

    Full Text Available Measuring behaviour, especially oral behaviour, has always been a debated issue: therefore the aim of this paper is to closely examine the study of oral behaviour in calves and the approaching methodology. Behavioural observations were conducted by two media (direct observations by check sheets and indirect observations by videotapes recorded by cam- eras connected to a digital field switcher and a time-lapse video recorder in order to compare data and assess the reli- ability and validity of the two methods in identifying some oral behavioural patterns in calves. The study was carried out on 54 Polish Friesian calves housed in group pens and in individual crates. The behaviour of the calves was investigated during the fattening period on the 2nd, 7th, 13th, 18th and 23rd week, one hour before and one hour after each of the two meals. Two experienced observers checked the behaviour of the calves, including oral behaviours on structures and buckets and oral stereotypies, by direct observations using a scan sampling every 2 min- utes. The calves' behaviour was also video recorded on the same days in which the direct observations were carried out and analysed by the same two observers. Percentages of time spent on each type of behaviour were calculated and anal- ysed by Chi-square test. Regardless of the housing system, the comparison between direct and indirect observations revealed significant differences in almost every behavioural category. Licking, biting and nibbling structures, nibbling and sucking the bucket, playing with the bucket and the teat, chewing and oral stereotypies were significantly higher in direct observations compared to indirect (P < 0.001, while inactivity was higher in video recorded observations (P < 0.001. In conclusion, regardless of the type of housing, our results revealed an objective difficulty in analysing videotapes with very detailed behavioural categories, like oral behaviours. Although video recording can

  16. Interlaboratory comparison of measurements of acid-volatile sulfide and simultaneously extracted nickel in spiked sediments

    Science.gov (United States)

    Brumbaugh, William G.; Hammerschmidt, Chad R.; Zanella, Luciana; Rogevich, Emily; Salata, Gregory; Bolek, Radoslaw

    2011-01-01

    An interlaboratory comparison of acid-volatile sulfide (AVS) and simultaneously extracted nickel (SEM_Ni) measurements of sediments was conducted among five independent laboratories. Relative standard deviations for the seven test samples ranged from 5.6 to 71% (mean?=?25%) for AVS and from 5.5 to 15% (mean?=?10%) for SEM_Ni. These results are in stark contrast to a recently published study that indicated AVS and SEM analyses were highly variable among laboratories.

  17. Direct carbon-carbon coupling of furanics with acetic acid over Brønsted zeolites

    Science.gov (United States)

    Gumidyala, Abhishek; Wang, Bin; Crossley, Steven

    2016-01-01

    Effective carbon-carbon coupling of acetic acid to form larger products while minimizing CO2 emissions is critical to achieving a step change in efficiency for the production of transportation fuels from sustainable biomass. We report the direct acylation of methylfuran with acetic acid in the presence of water, all of which can be readily produced from biomass. This direct coupling limits unwanted polymerization of furanics while producing acetyl methylfuran. Reaction kinetics and density functional theory calculations illustrate that the calculated apparent barrier for the dehydration of the acid to form surface acyl species is similar to the experimentally measured barrier, implying that this step plays a significant role in determining the net reaction rate. Water inhibits the overall rate, but selectivity to acylated products is not affected. We show that furanic species effectively stabilize the charge of the transition state, therefore lowering the overall activation barrier. These results demonstrate a promising new route to C–C bond–forming reactions for the production of higher-value products from biomass. PMID:27652345

  18. The Importance of Monitoring for the Effectiveness of Environmental DirectivesA Comparison of Monitoring Obligations in European Environmental Directives

    Directory of Open Access Journals (Sweden)

    Barbara A. Beijen

    2014-05-01

    Full Text Available European environmental directives contain various norms and standards, such as quality standards or emission standards. The goal of these directives is often to improve the environmental quality and the protection of biodiversity and ecosystems, to be achieved by Member States by complying with these norms. However, in order to ensure that they will do so, many directives contain additional instruments, such as the obligation to set up action programmes and an obligation to monitor and report the results to the European Commission. These obligations are essential for directives to be effective, but the form and contents of these obligations tend to differ. Some directives contain strict norms with detailed information on when and where to monitor, whereas other directives leave the Member States much more freedom. This article will focus on the monitoring obligations in European environmental directives, their objectives and the different designs.

  19. Optimization of direct acid esterification process of soybean oil deodorizer distillate

    Directory of Open Access Journals (Sweden)

    Barrera-Arellano, Daniel

    2002-06-01

    Full Text Available In this research work, the reaction conditions for the direct acid esterification of free fatty acid from soybean oil deodorizer distillate was optimized, using anhydrous ethyl alcohol and concentrated sulfuric acid as catalyst to determine the best process conditions to get the best conversion rates of free fatty acids to ethylic esters, preserving the tocopherols. The conversion extent of free fatty acids to ethyl esters was optimized using a Response Surface Methodology obtained through a second order factorial experimental design. The optima conditions for the direct acid esterification of soybean oil deodorizer distillate were: ethanol:free fatty acids from 6.4 to 11.2:1, H2SO4 concentration from 0.9 to 1.5 % and reaction time from 1.3 to 2.6 h, with conversions extent above 94 %. No significant tocopherol losses were observed during the process. Results showed a good fit between mathematical model and data obtained at different processing conditions, making this model predictive and statistically significant (pEn este estudio fueron optimizadas las condiciones de reacción de esterificación ácida directa de los ácidos grasos libres del destilado de desodorización del aceite de soja, usando alcohol etílico anhidro y ácido sulfúrico concentrado como catalizador. Fueron determinadas las mejores condiciones de proceso para obtener las tasas de conversión más altas de ácidos grasos libres en ésteres etílicos, manteniendo los tocoferoles. Los resultados fueron analizados mediante la metodología de superficie de respuesta usando un delineamiento experimental factorial completo de segundo orden. Las condiciones óptimas encontradas para la esterificación ácida directa del destilado de desodorización del aceite de soja obtenidas fueron: etanol:ácidos grasos libres entre 6.4 y 11.2:1, concentración de ácido sulfúrico entre 0.9 y 1.5 % y tiempo de reacción entre 1.3 y 2.6 h, obteniendo tasas de conversión mayores que 94 %. No

  20. Direct determination of amino acids and carbohydrates by high-performance capillary electrophoresis with refractometric detection.

    Science.gov (United States)

    Ivano, A R; Nazimov, I V; Lobazov, A P; Popkovich, G B

    2000-10-13

    This is an initial report to propose a novel approach in high-performance capillary electrophoresis (HPCE) for the direct detection of compounds without natural absorbance in the UV and visible spectral range, such as amino acids and carbohydrates. A refractometry detector with the 2 nl cell (Applied Systems, Minsk, Belarus) was employed to identify amino acids and carbohydrates without derivatization. The first results are provided on separation of seven free amino acids in the phosphate running buffer and three free carbohydrates in the borate-sodium dodecyl sulfate running buffer and detection by refractometer. Fused capillaries of 50 or 75 microm internal diameter and separation voltage (10-23 kV) were applied. Detection limits ranged typically from 10 to 100 fmol and the response was linear over two orders of magnitude for most of the amino acids and carbohydrates. The HPCE system demonstrated good long-term stability and reproducibility with a relative standard deviation, less than 5% for the migration time (n=10).

  1. Direct Comparison of the X-Ray Emission and Absorption of Cerium Oxide

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, J G; Yu, S W; Chung, B W; Waddill, G D; Denlinger, J D

    2010-11-24

    Bremstrahlung Isochromat Spectroscopy (BIS). The XES spectra were collected using a Specs electron gun for the excitation and the XES 350 grating monochromator and channel plate system from Scienta as the photon detection. Spectra were collected in 'normal mode,' where the electron gun kinetic energy (KE) and the energy position of the center of the channel plate were both fixed and the energy distribution in the photon (hv) spectrum was derived from the intensities distributed across the channel plate detector in the energy dispersal direction. The polycrystalline Ce sample was oxidized by exposure to air at ambient pressures. After introduction to the ultra-high vacuum system, the oxidized sample was bombarded with Ar, to clean the topmost surface region and stabilize the surface and near surface regions. Although CeO{sub 2} would be the thermodynamically preferred composition in an oxygen rich environment, the combination of a vacuum environment and ion etching may have driven the near surface region into a Ce{sub 2}O{sub 3} stoichiometry. XES data collection occurred with the sample at or near room temperature. The base pressure of the system was 3 x 10{sup -10} torr, but the pressure changed depending the energy and current of the electron gun. For example, with the XES measurements at KE = 3KeV, the pressure was approximately 8 to 9 x 10{sup -10} torr and the excitation current to the sample was typically 0.01 mA. More detail of the sample preparation and analysis can be found in Reference 1. The XAS experiments were performed at Beamline 8 of the Advance Light Source, as part of a larger collaboration. The ex situ sample used at the ALS was prepared in a fashion similar to that described above. X-ray Emission Spectroscopy (XES) and X-ray Absorption Spectroscopy (XAS), have been used to investigate the photon emission and absorption associated with the Ce3d{sub 5/2} and Ce3d{sub 3/2} core-levels in CeOxide. A comparison of the two processes and

  2. Initial Comparison of Direct and Legacy Modeling Approaches for Radial Core Expansion Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Shemon, Emily R. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-10-10

    not conservative and could be overestimating reactivity feedback effects that are closely tied to reactor safety. We conclude that there is indeed value in performing direct simulation of deformed meshes despite the increased computational expense. PROTEUS-SN is already part of the SHARP multi-physics toolkit where both thermal hydraulics and structural mechanical feedback modeling can be applied but this is the first comparison of direct simulation to legacy techniques for radial core expansion.

  3. A soluble acid invertase is directed to the vacuole by a signal anchor mechanism.

    Science.gov (United States)

    Rae, Anne L; Casu, Rosanne E; Perroux, Jai M; Jackson, Mark A; Grof, Christopher P L

    2011-06-15

    Enzyme activities in the vacuole have an important impact on the net concentration of sucrose. In sugarcane (Saccharum hybrid), immunolabelling demonstrated that a soluble acid invertase (β-fructofuranosidase; EC 3.2.1.26) is present in the vacuole of storage parenchyma cells during sucrose accumulation. Examination of sequences from sugarcane, barley and rice showed that the N-terminus of the invertase sequence contains a signal anchor and a tyrosine motif, characteristic of single-pass membrane proteins destined for lysosomal compartments. The N-terminal peptide from the barley invertase was shown to be capable of directing the green fluorescent protein to the vacuole in sugarcane cells. The results suggest that soluble acid invertase is sorted to the vacuole in a membrane-bound form.

  4. Water-Dispersible Silica-Polyelectrolyte Nanocomposites Prepared via Acid-Triggered Polycondensation of Silicic Acid and Directed by Polycations

    Directory of Open Access Journals (Sweden)

    Philip Overton

    2016-03-01

    Full Text Available The present work describes the acid-triggered condensation of silicic acid, Si(OH4, as directed by selected polycations in aqueous solution in the pH range of 6.5–8.0 at room temperature, without the use of additional solvents or surfactants. This process results in the formation of silica-polyelectrolyte (S-PE nanocomposites in the form of precipitate or water-dispersible particles. The mean hydrodynamic diameter (dh of size distributions of the prepared water-dispersible S-PE composites is presented as a function of the solution pH at which the composite formation was achieved. Poly(2-(dimethylaminoethyl methacrylate (PDMAEMA and block copolymers of DMAEMA and oligo(ethylene glycol methyl ether methacrylate (OEGMA were used as weak polyelectrolytes in S-PE composite formation. The activity of the strong polyelectrolytes poly(methacryloxyethyl trimethylammonium iodide (PMOTAI and PMOTAI-b-POEGMA in S-PE formation is also examined. The effect of polyelectrolyte strength and the OEGMA block on the formation of the S-PE composites is assessed with respect to the S-PE composites prepared using the PDMAEMA homopolymer. In the presence of the PDMAEMA60 homopolymer (Mw = 9400 g/mol, the size of the dispersible S-PE composites increases with solution pH in the range pH 6.6–8.1, from dh = 30 nm to dh = 800 nm. S-PDMAEMA60 prepared at pH 7.8 contained 66% silica by mass (TGA. The increase in dispersible S-PE particle size is diminished when directed by PDMAEMA300 (Mw = 47,000 g/mol, reaching a maximum of dh = 75 nm. S-PE composites formed using PDMAEMA-b-POEGMA remain in the range dh = 20–30 nm across this same pH regime. Precipitated S-PE composites were obtained as spheres of up to 200 nm in diameter (SEM and up to 65% mass content of silica (TGA. The conditions of pH for the preparation of dispersible and precipitate S-PE nanocomposites, as directed by the five selected polyelectrolytes PDMAEMA60, PDMAEMA300, PMOTAI60, PDMAEMA60-b-POEGMA38 and

  5. Million-Body Star Cluster Simulations: Comparisons between Monte Carlo and Direct $N$-body

    CERN Document Server

    Rodriguez, Carl L; Wang, Long; Chatterjee, Sourav; Rasio, Frederic A; Spurzem, Rainer

    2016-01-01

    We present the first detailed comparison between million-body globular cluster simulations computed with a H\\'enon-type Monte Carlo code, CMC, and a direct $N$-body code, NBODY6++GPU. Both simulations start from an identical cluster model with $10^6$ particles, and include all of the relevant physics needed to treat the system in a highly realistic way. With the two codes "frozen" (no fine-tuning of any free parameters or internal algorithms of the codes) we find excellent agreement in the overall evolution of the two models. Furthermore, we find that in both models, large numbers of stellar-mass black holes (> 1000) are retained for 12 Gyr. Thus, the very accurate direct $N$-body approach confirms recent predictions that black holes can be retained in present-day, old globular clusters. We find only minor disagreements between the two models and attribute these to the small-$N$ dynamics driving the evolution of the cluster core for which the Monte Carlo assumptions are less ideal. Based on the overwhelming g...

  6. Environmental comparison of biobased chemicals from glutamic acid with their petrochemical equivalents.

    Science.gov (United States)

    Lammens, Tijs M; Potting, José; Sanders, Johan P M; De Boer, Imke J M

    2011-10-01

    Glutamic acid is an important constituent of waste streams from biofuels production. It is an interesting starting material for the synthesis of biobased chemicals, thereby decreasing the dependency on fossil fuels. The objective of this paper was to compare the environmental impact of four biobased chemicals from glutamic acid with their petrochemical equivalents, that is, N-methylpyrrolidone (NMP), N-vinylpyrrolidone (NVP), acrylonitrile (ACN), and succinonitrile (SCN). A consequential life cycle assessment was performed, wherein glutamic acid was obtained from sugar beet vinasse. The removed glutamic acid was substituted with cane molasses and ureum. The comparison between the four biobased and petrochemical products showed that for NMP and NVP the biobased version had less impact on the environment, while for ACN and SCN the petrochemical version had less impact on the environment. For the latter two an optimized scenario was computed, which showed that the process for SCN can be improved to a level at which it can compete with the petrochemical process. For biobased ACN large improvements are required to make it competitive with its petrochemical equivalent. The results of this LCA and the research preceding it also show that glutamic acid can be a building block for a variety of molecules that are currently produced from petrochemical resources. Currently, most methods to produce biobased products are biotechnological processes based on sugar, but this paper demonstrates that the use of amino acids from low-value byproducts can certainly be a method as well.

  7. Direct Synthesis of Phenol from Benzene on an Activated Carbon Catalyst Treated with Nitric Acid

    Institute of Scientific and Technical Information of China (English)

    Cui-hong Chen; Jia-quan Xu; Ming-ming Jin; Gui-ying Li; Chang-wei Hu

    2011-01-01

    Commercially available coal-based activated carbon was treated by nitric acid with different concentrations and the resultant samples were used as catalysts for the direct hydroxylation of benzene to phenol in acetonitrile. Boehm titration, X-ray photoelectron spectroscopy,scanning electron microscope coupled with an energy dispersive X-ray microanalyzer, and Brunauer-Emmett-Teller method were used to characterize toe samples. The number of carboxyl groups on the surface was found to be the main factor affecting the catalytic activity. An optimum catalytic performance with a yield of 15.7% and a selectivity of 87.2% to phenol was obtained.

  8. Comparison of indirect and direct quantification of esters of monochloropropanediol in vegetable oil.

    Science.gov (United States)

    Dubois, Mathieu; Tarres, Adrienne; Goldmann, Till; Empl, Anna Maria; Donaubauer, Alfred; Seefelder, Walburga

    2012-05-04

    The presence of fatty acid esters of monochloropropanediol (MEs) in food is a recent concern raised due to the carcinogenicity of their hydrolysable moieties 2- and 3-monochloropropanediol (2- and 3-MCPD). Several indirect methods for the quantification of MEs have been developed and are commonly in use until today, however significant discrepancies among analytical results obtained are challenging their reliability. The aim of the present study was therefore to test the trueness of an indirect method by comparing it to a newly developed direct method using palm oil and palm olein as examples. The indirect method was based on ester cleavage under acidic conditions, derivatization of the liberated 2- and 3-MCPD with heptafluorobutyryl imidazole and GC-MS determination. The direct method was comprised of two extraction procedures targeting 2-and 3-MCPD mono esters (co-extracting as well glycidyl esters) by the use of double solid phase extraction (SPE), and 2- and 3-MCPD di-esters by the use of silica gel column, respectively. Detection was carried out by liquid chromatography coupled to time of flight mass spectrometry (LC-ToF-MS). Accurate quantification of the intact compounds was assured by means of matrix matched standard addition on extracts. Analysis of 22 palm oil and 7 palm olein samples (2- plus 3-MCPD contamination ranged from 0.3 to 8.8 μg/g) by both methods revealed no significant bias. Both methods were therefore considered as comparable in terms of results; however the indirect method was shown to require less analytical standards, being less tedious and furthermore applicable to all type of different vegetable oils and hence recommended for routine application.

  9. Direct synthesis of graphene nanosheets support Pd nanodendrites for electrocatalytic formic acid oxidation

    Institute of Scientific and Technical Information of China (English)

    杨苏东; 陈琳

    2015-01-01

    We report a solvothermal method preparation of dendritic Pd nanoparticles (DPNs) and spherical Pd nanoparticles (SPNs) supported on reduced graphene oxide (RGO). Drastically different morphologies of Pd NPs with nanodendritic structures or spherical structures were observed on graphene by controlling the reduction degree of graphene oxide (GO) un-der mild conditions. In addition to being a commonplace substrate, GO plays a more important role that relies on its surface groups, which serves as a shape-directing agent to direct the dendritic growth. As a result, the obtained DPNs/RGO catalyst exhibits a significantly enhanced electro-catalytic behavior for the oxidation of formic acid compared to the SPNs/RGO catalyst.

  10. Direct Isolation of Purines and Pyrimidines from Nucleic Acids Using Sublimation

    Science.gov (United States)

    Glavin, Daniel P.; Schubert, Michael; Bada, Jeffrey L.

    2003-01-01

    A sublimation technique was developed to isolate purines and pyrimidines directly from lambda-deoxyribonucleic acid (lambda-DNA) and Escherichia coli cells. The sublimation of adenine, cytosine, guanine, and thymine from lambda-DNA was tested under reduced pressure (approx. 0.5 Torr) at temperatures of >150 C. With the exception of guanine, approximately 60 -75% of each base was sublimed directly from the lambda-DNA and recovered on a coldfinger of the sublimation apparatus after heating to 450 C. Several nucleobases including adenine, cytosine, thymine, and uracil were also recovered from E. coli bacteria after heating the cells to the same temperature, although some thermal decomposition of the bases also occurred. These results demonstrate the feasibility of using sublimation to isolate purines and pyrimidines from native E. coli DNA and RNA without any chemical treatment of the cells.

  11. A comparison of direct infusion MS and GC-MS for metabolic footprinting of yeast mutants

    DEFF Research Database (Denmark)

    Mass, S.; Villas-Bôas, Silas Granato; Hansen, Michael Adsetts Edberg;

    2007-01-01

    Recent technical advances in mass spectrometry (MS) have propelled this technology to the forefront of methods employed in metabolome analysis. Here, we compare two distinct analytical approaches based on MS for their potential in revealing specific metabolic footprints of yeast single-deletion m......Recent technical advances in mass spectrometry (MS) have propelled this technology to the forefront of methods employed in metabolome analysis. Here, we compare two distinct analytical approaches based on MS for their potential in revealing specific metabolic footprints of yeast single......-deletion mutants. Filtered fermentation broth samples were analyzed by GC-MS and direct infusion ESI-MS. The potential of both methods in producing specific and, therefore, discriminant metabolite profiles was evaluated using samples from several yeast deletion mutants grown in batch-culture conditions....... Thus, the GC-MS method is good for classification of mutants with altered nitrogen regulation as it primarily measures amino acids, whereas this method cannot classify mutants involved in regulation of phospholipids metabolism as well as the direct infusion MS (DI-MS) method. From the analysis, we find...

  12. A new HPLC method for the direct analysis of triglycerides of dicarboxylic acids in biological samples.

    Science.gov (United States)

    Capristo, E; Mingrone, G; De Gaetano, A; Addolorato, G; Greco, A V; Gasbarrini, G

    1999-11-01

    Dicarboxylic acids (DA) are alternate lipid substrates recently proposed in parenteral nutrition. Two new derivatives of DA, a triglyceride of sebacic (TGC10) and one of dodecanedioic (TGC12) acid have been synthesised in order to reduce the amount of sodium given with the unesterified forms. The present paper describes a rapid and direct high-performance liquid chromatographic method (HPLC) for the analysis of these substances in both plasma and urine. Thirty-six male Wistar rats were rapidly injected with 64 mg of TGC10 or 53 mg of TGC12. The triglycerides and their products of hydrolysis were measured in plasma samples taken at different times. For the dose of 500 ng the intra-assay variations ranged from 6. 80+/-0.35% for TGC10 to 18.6+/-3.20% for TGC12 and the inter-assay variations were from 4.44+/-2.21% for TGC10 to 15.0+/-6.72% for TGC12. The detection limit for both triglycerides was 5 ng. This rapid and direct HPLC method could have practical implications in monitoring the concentration of both triglycerides and free forms of DA in biological samples of patients who might benefit from the administration of these substances during parenteral nutrition regimens.

  13. [Development of direct competitive enzyme-linked immunosorbent assay for the determination of domoic acid].

    Science.gov (United States)

    Wang, Qian; Cheng, Jin-Ping; Gao, Li-Li; Dong, Yu; Xi, Lei

    2012-02-01

    To develop a direct competitive enzyme-linked immunosorbent assay (ELISA) for rapid detection of domoic acid concentrations, HRP (horse radish peroxidase) was successfully linked to DA using EDC. The concentration of DA was quantitatively analyzed on the basic of the specific immune responses between the DA- HRP and the monoclonal antibodies made in advance. Calibration curve were established after the optimization of reaction conditions such as the type of blocking solution, the blocking time and the incubation temperature. The results show that, the best reaction condition of the direct competitive ELISA is 1% gelatin, blocking 1 h at 37 degrees C, incubating 1 h at 37 degrees C after the monoclonal antibodies added. The detect limit is 3.58 ng x mL(-1), the coefficient of variation between the holes is below 15%, and the recovery is 80% - 120%. The whole analysis process could be completed within 1.5 h. It meets the requirements of rapid and batch detection of domoic acid. The method will have broad development prospects.

  14. Site directed mutagenesis of StSUT1 reveals target amino acids of regulation and stability.

    Science.gov (United States)

    Krügel, Undine; Wiederhold, Elena; Pustogowa, Jelena; Hackel, Aleksandra; Grimm, Bernhard; Kühn, Christina

    2013-11-01

    Plant sucrose transporters (SUTs) are functional as sucrose-proton-cotransporters with an optimal transport activity in the acidic pH range. Recently, the pH optimum of the Solanum tuberosum sucrose transporter StSUT1 was experimentally determined to range at an unexpectedly low pH of 3 or even below. Various research groups have confirmed these surprising findings independently and in different organisms. Here we provide further experimental evidence for a pH optimum at physiological extrema. Site directed mutagenesis provides information about functional amino acids, which are highly conserved and responsible for this extraordinary increase in transport capacity under extreme pH conditions. Redox-dependent dimerization of the StSUT1 protein was described earlier. Here the ability of StSUT1 to form homodimers was demonstrated by heterologous expression in Lactococcus lactis and Xenopus leavis using Western blots, and in plants by bimolecular fluorescence complementation. Mutagenesis of highly conserved cysteine residues revealed their importance in protein stability. The accessibility of regulatory amino acid residues in the light of StSUT1's compartmentalization in membrane microdomains is discussed.

  15. Direct conversion of corn cob to formic and acetic acids over nano oxide catalysts

    Institute of Scientific and Technical Information of China (English)

    Liyuan; Cheng; Hong; Liu; Yuming; Cui; Nianhua; Xue; Weiping; Ding

    2014-01-01

    Considering energy shortage, large molecules in corn cob and easy separation of solid catalysts, nano oxides are used to transform corn cob into useful chemicals. Because of the microcrystals, nano oxides offer enough accessible sites for cellulose, hemicellulose and monosaccharide from corn cob hydrolysis and oxidant. Chemical conversion of corn cob to organic acids is investigated over nano ceria, alumina, titania and zirconia under various atmospheres. Liquid products are mainly formic and acetic acids. A small amount of other compounds, such as D-xylose,D-glucose, arabinose and xylitol are also detected simultaneously. The yield of organic acids reaches 25%–29% over the nano oxide of ceria,zirconia and alumina with 3 h reaction time under 453 K and 1.2 MPa O2. The unique and fast conversion of corn cob is directly approached over the nano oxides. The results are comparative to those of biofermentation and offer an alternative method in chemically catalytic conversion of corn cob to useful chemicals in a one-pot chemical process.

  16. New method for the direct determination of dissolved Fe(III) concentration in acid mine waters

    Science.gov (United States)

    To, T.B.; Nordstrom, D.K.; Cunningham, K.M.; Ball, J.W.; McCleskey, R.B.

    1999-01-01

    A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II) >> Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes in Fe reduction-oxidation distribution. Complexed Fe(II) is cleanly removed using a silica-based, reversed-phase adsorbent, yielding excellent isolation of the Fe(III) complex. Iron(III) concentration is measured colorimetrically or by graphite furnace atomic absorption spectrometry (GFAAS). The method requires inexpensive commercial reagents and simple procedures that can be used in the field. Calcium(II), Ni(II), Pb(II), AI(III), Zn(II), and Cd(II) cause insignificant colorimetric interferences for most acid mine waters. Waters containing >20 mg of Cu/L could cause a colorimetric interference and should be measured by GFAAS. Cobalt(II) and Cr(III) interfere if their molar ratios to Fe(III) exceed 24 and 5, respectively. Iron(II) interferes when its concentration exceeds the capacity of the complexing ligand (14 mg/L). Because of the GFAAS elemental specificity, only Fe(II) is a potential interferent in the GFAAS technique. The method detection limit is 2 ??g/L (40 nM) using GFAAS and 20 ??g/L (0.4 ??M) by colorimetry.A new method for direct determination of dissolved Fe(III) in acid mine water has been developed. In most present methods, Fe(III) is determined by computing the difference between total dissolved Fe and dissolved Fe(II). For acid mine waters, frequently Fe(II)???Fe(III); thus, accuracy and precision are considerably improved by determining Fe(III) concentration directly. The new method utilizes two selective ligands to stabilize Fe(III) and Fe(II), thereby preventing changes

  17. Biodiesel production by direct esterification of fatty acids with propyl and butyl alcohols

    Directory of Open Access Journals (Sweden)

    Ferial A. Zaher

    2015-12-01

    Full Text Available The expected depletion of natural petroleum resources in the near future and pollution of the environment due to excessive carbon dioxide emissions by fossil fuel and its adverse effect on global warming constitute two major problems facing the whole world. In view of these problems, much research work is now directed worldwide to find fuels alternative to those derived from petroleum which should be renewable and more environmentally friendly fuels. Biodiesel fuel which is a blend of fatty acid esters with alcohols is considered the most suitable alternative fuel for diesel engines. In this scope of research work, a previous study (Soliman et al., 2013 has been made to explore the opportunity of utilizing the fatty acids that can be obtained from the waste of edible oil industry in Egypt to produce biodiesel fuel by direct esterification with methanol as well as ethanol in the presence of sulfuric acid as a catalyst. This paper is a continuation of that work where two other alcohols of a chain length longer than ethanol have been used being propanol and butanol. The performance of a diesel engine running using a 50% blend of regular diesel fuel and each of the two biodiesels prepared was compared to that using regular diesel fuel. The results have shown that the brake specific fuel consumption (BSFC and the brake thermal efficiency at full engine loading were almost the same in all cases. This indicates that the produced fuel could be used as an efficient fuel substitute for diesel engines. By comparing the results of the present work to those reported in our previous work, it appeared that methanol which has the shortest carbon chain length is the most recommended in view of the brake thermal efficiency of a diesel engine at full loading.

  18. Direct Oxidation of Ethene to Acetic Acid over Pd-H4SiW12O40-Based Catalyst

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@The direct oxidation of ethene to acetic acid has the advantages of abundant raw materials and low cost of equipment[1],hence the research for this process has been of much interest in industry application.

  19. Engineering the properties of D-amino acid oxidases by a rational and a directed evolution approach.

    Science.gov (United States)

    Pollegioni, Loredano; Sacchi, Silvia; Caldinelli, Laura; Boselli, Angelo; Pilone, Mirella S; Piubelli, Luciano; Molla, Gianluca

    2007-12-01

    D-amino acid oxidase (DAAO) is a FAD-containing flavoprotein that dehydrogenates the D-isomer of amino acids to the corresponding imino acids, coupled with the reduction of FAD. The cofactor then reoxidizes on molecular oxygen and the imino acid hydrolyzes spontaneously to the alpha-keto acid and ammonia. In vitro DAAO displays broad substrate specificity, acting on several neutral and basic D-amino acids: the most efficient substrates are amino acids with hydrophobic side chains. D-aspartic acid and D-glutamic acid are not substrates for DAAO. Through the years, it has been the subject of a number of structural, functional and kinetic investigations. The most recent advances are represented by site-directed mutagenesis studies and resolution of the 3D-structure of the enzymes from pig, human and yeast. The two approaches have given us a deeper understanding of the structure-function relationships and promoted a number of investigations aimed at the modulating the protein properties. By a rational and/or a directed evolution approach, DAAO variants with altered substrate specificity (e.g., active on acidic or on all D-amino acids), increased stability (e.g., stable up to 60 degrees C), modified interaction with the flavin cofactor, and altered oligomeric state were produced. The aim of this paper is to provide an overview of the most recent research on the engineering of DAAOs to illustrate their new intriguing properties, which also have enabled us to pursue new biotechnological applications.

  20. Acid reflux directly causes sleep disturbances in rat with chronic esophagitis.

    Directory of Open Access Journals (Sweden)

    Kenichi Nakahara

    Full Text Available BACKGROUND & AIMS: Gastroesophageal reflux disease (GERD is strongly associated with sleep disturbances. Proton pump inhibitor (PPI therapy improves subjective but not objective sleep parameters in patients with GERD. This study aimed to investigate the association between GERD and sleep, and the effect of PPI on sleep by using a rat model of chronic acid reflux esophagitis. METHODS: Acid reflux esophagitis was induced by ligating the transitional region between the forestomach and the glandular portion and then wrapping the duodenum near the pylorus. Rats underwent surgery for implantation of electrodes for electroencephalogram and electromyogram recordings, and they were transferred to a soundproof recording chamber. Polygraphic recordings were scored by using 10-s epochs for wake, rapid eye movement sleep, and non-rapid eye movement (NREM sleep. To examine the role of acid reflux, rats were subcutaneously administered a PPI, omeprazole, at a dose of 20 mg/kg once daily. RESULTS: Rats with reflux esophagitis presented with several erosions, ulcers, and mucosal thickening with basal hyperplasia and marked inflammatory infiltration. The reflux esophagitis group showed a 34.0% increase in wake (232.2±11.4 min and 173.3±7.4 min in the reflux esophagitis and control groups, respectively; p<0.01 accompanied by a reduction in NREM sleep during light period, an increase in sleep fragmentation, and more frequent stage transitions. The use of omeprazole significantly improved sleep disturbances caused by reflux esophagitis, and this effect was not observed when the PPI was withdrawn. CONCLUSIONS: Acid reflux directly causes sleep disturbances in rats with chronic esophagitis.

  1. Merging Photoredox and Nickel Catalysis: The Direct Synthesis of Ketones by the Decarboxylative Arylation of α-Oxo Acids.

    Science.gov (United States)

    Chu, Lingling; Lipshultz, Jeffrey M; MacMillan, David W C

    2015-06-26

    The direct decarboxylative arylation of α-oxo acids has been achieved by synergistic visible-light-mediated photoredox and nickel catalysis. This method offers rapid entry to aryl and alkyl ketone architectures from simple α-oxo acid precursors via an acyl radical intermediate. Significant substrate scope is observed with respect to both the oxo acid and arene coupling partners. This mild decarboxylative arylation can also be utilized to efficiently access medicinal agents, as demonstrated by the rapid synthesis of fenofibrate.

  2. Carbon-11 and iodine-123 labelled iomazenil: a direct PET-SPET comparison

    Energy Technology Data Exchange (ETDEWEB)

    Westera, G. [Div. of Nuclear Medicine, Dept. of Radiology, Univ. Hospital Zurich (Switzerland); Buck, A. [Div. of Nuclear Medicine, Dept. of Radiology, Univ. Hospital Zurich (Switzerland); Burger, C. [Div. of Nuclear Medicine, Dept. of Radiology, Univ. Hospital Zurich (Switzerland); Leenders, K.L. [Paul Scherrer Inst., Villigen (Switzerland); Schulthess, G.K. von [Div. of Nuclear Medicine, Dept. of Radiology, Univ. Hospital Zurich (Switzerland); Schubiger, A.P. [Paul Scherrer Inst., Villigen (Switzerland)

    1996-01-01

    The benzodiazepine receptor ligand iomazenil was labelled with carbon-11 to allow a direct positron emission tomography/single-photon emission tomography (PET/SPET) comparison with the well-known iodine-123 labelled compound. Imaging showed the same regional distribution for both modalities. Blood sample activity was corrected for metabolites by extraction with chloroform and high-performance liquid chromatographic analysis. Metabolism is very fast: 5 Min after application more than 85% of the plasma activity is present as hydrophilic metabolites. Kinetic methods were used to obtain regional estimates of transport rate constants and receptor concentrations. A three-compartment model was employed which gave transport rate constants for brain uptake (K{sub 1}) and the distribution volume for the specifically receptor bound compartment (DV{sub S}). K{sub 1} varied from 0.32 to 0.50 ml/min per gram for the cortical regions, cerebellum, thalamus and striatum for PET and SPET. The coefficient of variation of the SPET parameters was quite comparable to that of the PET parameters, especially after 180 min (PET 90 min) study duration. Thus quantitative benzodiazepine receptor information can be obtained from dynamic SPET imaging in the same way as with PET. (orig./MG)

  3. Comparisons of spectral characteristics of wind noise between omnidirectional and directional microphones.

    Science.gov (United States)

    Chung, King

    2012-06-01

    Wind noise reduction is a topic of ongoing research and development for hearing aids and cochlear implants. The purposes of this study were to examine spectral characteristics of wind noise generated by directional (DIR) and omnidirectional (OMNI) microphones on different styles of hearing aids and to derive wind noise reduction strategies. Three digital hearing aids (BTE, ITE, and ITC) were fitted to Knowles Electronic Manikin for Acoustic Research. They were programmed to have linear amplification and matching frequency responses between the DIR and OMNI modes. Flow noise recordings were made from 0° to 360° azimuths at flow velocities of 4.5, 9.0, and 13.5 m/s in a quiet wind tunnel. Noise levels were analyzed in one-third octave bands from 100 to 8000 Hz. Comparison of wind noise revealed that DIR generally produced higher noise levels than OMNI for all hearing aids, but it could result in lower levels than OMNI at some frequencies and head angles. Wind noise reduction algorithms can be designed to detect noise levels of DIR and OMNI outputs in each frequency channel, remove the constraint to switch to OMNI in low-frequency channel(s) only, and adopt the microphone mode with lower noise levels to take advantage of the microphone differences.

  4. Spectroscopic investigation and direct comparison of the reactivities of iron pyridyl oxidation catalysts

    Science.gov (United States)

    Song, Yang; Mayes, Howard G.; Queensen, Matthew J.; Bauer, Eike B.; Dupureur, Cynthia M.

    2017-03-01

    The growing interest in green chemistry has fueled attention to the development and characterization of effective iron complex oxidation catalysts. A number of iron complexes are known to catalyze the oxidation of organic substrates utilizing peroxides as the oxidant. Their development is complicated by a lack of direct comparison of the reactivities of the iron complexes. To begin to correlate reactivity with structural elements, we compare the reactivities of a series of iron pyridyl complexes toward a single dye substrate, malachite green (MG), for which colorless oxidation products are established. Complexes with tetradentate, nitrogen-based ligands with cis open coordination sites were found to be the most reactive. While some complexes reflect sensitivity to different peroxides, others are similarly reactive with either H2O2 or tBuOOH, which suggests some mechanistic distinctions. [Fe(S,S-PDP)(CH3CN)2](SbF6)2 and [Fe(OTf)2(tpa)] transition under the oxidative reaction conditions to a single intermediate at a rate that exceeds dye degradation (PDP = bis(pyridin-2-ylmethyl) bipyrrolidine; tpa = tris(2-pyridylmethyl)amine). For the less reactive [Fe(OTf)2(dpa)] (dpa = dipicolylamine), this reaction occurs on a timescale similar to that of MG oxidation. Thus, the spectroscopic method presented herein provides information about the efficiency and mechanism of iron catalyzed oxidation reactions as well as about potential oxidative catalyst decomposition and chemical changes of the catalyst before or during the oxidation reaction.

  5. A Direct Comparison between Static and Dynamic Melting Temperature Determinations below 100 GPa

    Institute of Scientific and Technical Information of China (English)

    SUN Yu-Huai; HUANG Hai-Jun; LIU Fu-Sheng; YANG Mei-Xia; JING Fu-Qian

    2005-01-01

    @@ A preliminary experiment of sound velocity measurements for porous iron with initial average density of 6.275 g/cm3 has been performed at pressures below 100 GPa, in order to clarify a long-standing problem that the static melting temperature Tm, mostly below 100 GPa due to its technical limitations, is notably lower than the extrapolated melting data inferred from the shock wave experiments made above 200 GPa, for the sake of making a direct comparison between the experimental static and dynamic melting temperatures in the same pressure region.With the lately proposed Hugoniot sound velocity data analysis technique [Chin. Phys. Lett. 22 (2005) 863], the results deduced from this Hugoniot sound velocity measurement is Tm = 3200 K at 87GPa and Tm = 3080 K at80 GPa, which are in good agreement with the two latest static data ofTm = 3510 K at 105 GPa and Tm = 2750 K at 58 GPa, which utilized modern improved double-side laser heating and in situ accurate x-ray diffraction techniques in experiments. It can be concluded that consensus Tm data would be obtained from static and shock wave experiments in the case that the recently improved techniques are adopted in investigations.

  6. Comparison of Direct and Array-Derived Strain and Rotation at the Pinon Flat Observatory, California

    Science.gov (United States)

    Lin, Chin-Jen; Vernon, Frank; Wassermann, Joachim; Gebauer, André; Schreiber, Ulrich; Carr Agnew, Duncan; Igel, Heiner

    2016-04-01

    To fully understand the wave motion of a deformable body, we need 12 components in total: 3 components of translation, 3 components of rotation, and 6 components of strain. Translation are routinely recorded in the seismology community. Strain measurements are rare and do not routinely enter the inversion procedures for structure and source from seismic observations. Single-component rotational ground motions have been measured just recently. In principle, strains and rotations can be derived from an array of seismic stations, under uniform strain assumption across the array. In a unique instrument setting at the PFO (Pinon Flat Observatory, California), a dense small-aperture seismic array is in the vicinity of a sensor measuring rotations around a vertical axis (ring laser) and three horizontal strain meters. This enables us to compare array derived strain/rotation with observations for 10/12 components of complete ground motion. We show the comparison results between array-derived ground motion and direct observation for tele-seismic events. Several possible errors like tilt couplings, array size, seismometer noise are discussed.

  7. Direct Determination of Ascorbic Acid in a Grapefruit: Paving the Way for In Vivo Spectroelectrochemistry.

    Science.gov (United States)

    Garoz-Ruiz, Jesus; Heras, Aranzazu; Colina, Alvaro

    2017-02-07

    The study of real samples is more complicated than the study of other systems. However, the inherent advantages of UV-vis absorption spectroelectrochemistry should overcome some difficulties related to direct measurements in complex matrices. For this reason, a singular spectroelectrochemistry device has been fabricated and validated. The novel cell is based on single-walled carbon nanotubes, which are filtered and subsequently press-transferred on a polyethylene terephthalate support using a stencil with a custom design. With this new methodology, working, counter, and reference electrodes are completely flat on the surface, where two optical fibers are fixed in a long optical path length configuration. To demonstrate the usefulness of this device and the power of spectroelectrochemistry techniques to solve problems of the current world, this device is used to quantitatively detect the concentration of ascorbic acid in a complex matrix such as a fruit, directly, without any previous sample pretreatment. The ease to fabricate the device, the advantages related to its use, and the excellent results obtained not only with univariate but also with multivariate analysis, shed more light on the analysis of samples as they occur in nature. According to the particular features of this cell, to the best of our knowledge this is the first spectroelectrochemical sensor that can be inserted directly in a biological matrix, laying the groundwork to perform in vivo measurements in a near future.

  8. Applicability Comparison of Methods for Acid Generation Assessment of Rock Samples

    Science.gov (United States)

    Oh, Chamteut; Ji, Sangwoo; Yim, Giljae; Cheong, Youngwook

    2014-05-01

    Minerals including various forms of sulfur could generate AMD (Acid Mine Drainage) or ARD (Acid Rock Drainage), which can have serious effects on the ecosystem and even on human when exposed to air and/or water. To minimize the hazards by acid drainage, it is necessary to assess in advance the acid generation possibility of rocks and estimate the amount of acid generation. Because of its relatively simple and effective experiment procedure, the method of combining the results of ABA (Acid Base Accounting) and NAG (Net Acid Generation) tests have been commonly used in determining acid drainage conditions. The simplicity and effectiveness of the above method however, are derived from massive assumptions of simplified chemical reactions and this often leads to results of classifying the samples as UC (Uncertain) which would then require additional experimental or field data to reclassify them properly. This paper therefore, attempts to find the reasons that cause samples to be classified as UC and suggest new series of experiments where samples can be reclassified appropriately. Study precedents on evaluating potential acid generation and neutralization capacity were reviewed and as a result three individual experiments were selected in the light of applicability and compatibility of minimizing unnecessary influence among other experiments. The proposed experiments include sulfur speciation, ABCC (Acid Buffering Characteristic Curve), and Modified NAG which are all improved versions of existing experiments of Total S, ANC (Acid Neutralizing Capacity), and NAG respectively. To assure the applicability of the experiments, 36 samples from 19 sites with diverse geologies, field properties, and weathering conditions were collected. The samples were then subject to existing experiments and as a result, 14 samples which either were classified as UC or could be used as a comparison group had been selected. Afterwards, the selected samples were used to conduct the suggested

  9. Direct comparison of highly efficient solution- and vacuum-processed organic solar cells based on merocyanine dyes

    Energy Technology Data Exchange (ETDEWEB)

    Kronenberg, Nils M.; Steinmann, Vera; Hertel, Dirk; Meerholz, Klaus [Department fuer Chemie, Universitaet Koeln, Luxemburger Strasse 116, 50939 Koeln (Germany); Buerckstuemmer, Hannah; Wuerthner, Frank [Institut fuer Organische Chemie and Roentgen Research Center for Complex Material Systems, Universitaet Wuerzburg, Am Hubland, 97074 Wuerzburg (Germany); Hwang, Jaehyung [BASF SE, Carl-Bosch-Strasse 38, 67056 Ludwigshafen (Germany)

    2010-10-01

    Identically configured bulk heterojunction organic solar cells based on merocyanine dye donor and fullerene acceptor compounds are manufactured either from solution or by vacuum deposition, to enable a direct comparison. Whereas the former approach is more suitable for screening purposes, the latter approach affords higher short-circuit current density and power conversion efficiency. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  10. Direct comparison of highly efficient solution- and vacuum-processed organic solar cells based on merocyanine dyes.

    Science.gov (United States)

    Kronenberg, Nils M; Steinmann, Vera; Bürckstümmer, Hannah; Hwang, Jaehyung; Hertel, Dirk; Würthner, Frank; Meerholz, Klaus

    2010-10-01

    Identically configured bulk heterojunction organic solar cells based on merocyanine dye donor and fullerene acceptor compounds (see figure) are manufactured either from solution or by vacuum deposition, to enable a direct comparison. Whereas the former approach is more suitable for screening purposes, the latter approach affords higher short-circuit current density and power conversion efficiency.

  11. Direct determination of creatinine based on poly(ethyleneimine)/phosphotungstic acid multilayer modified electrode.

    Science.gov (United States)

    Han, Ping; Xu, Shimei; Feng, Shun; Hao, Yanjun; Wang, Jide

    2016-05-01

    In this work, the direct determination of creatinine was achieved using a poly(ethyleneimine)/phosphotungstic acid multilayer modified electrode with the assistance of Copper(II) ions by cyclic voltammetry. The quantity of creatinine were determined by measuring the redox peak current of Cu(II)-creatinine complex/Cu(I)-creatinine complex. Factors affecting the response current of creatinine at the modified electrode were optimized. A linear relationship between the response current and the concentration of creatinine ranging from 0.125 to 62.5μM was obtained with a detection limit of 0.06μM. The proposed method was applied to determine creatinine in human urine, and satisfied results were gotten which was validated in accordance with high performance liquid chromatography. The proposed electrode provided a promising alternative in routine sensing for creatinine without enzymatic assistance.

  12. The Effects of Ellagic Acid upon Brain Cells: A Mechanistic View and Future Directions.

    Science.gov (United States)

    de Oliveira, Marcos Roberto

    2016-06-01

    Ellagic acid (EA, 2,3,7,8-tetrahydroxy-chromeno; C14H6O8) is a polyphenol derived from fruits (pomegranates, berries) and nuts. EA exhibits antioxidant capacity and induces anti-inflammatory actions in several mammalian tissues. EA has been characterized as a possible neuroprotective agent, but the number of reports is still limited to conclude whether and how EA exerts neuroprotection in humans. In this regard, performing additional studies considering the potential beneficial and/or toxicological roles for EA on brain cells would be an important step towards fully understanding of when and how EA may be securely utilized by humans as a neuroprotective agent. The aim of the present work is to discuss data related to the neuronal and glial effects of EA and the mechanisms underlying such events. Moreover, future directions are suggested as a potential guide to be utilized by researchers interested in investigating the neuronal and glial actions of EA hereafter.

  13. Modification of cellulose nanocrystals with lactic acid for direct melt blending with PLA

    Science.gov (United States)

    Spinella, Stephen; Re, Giada Lo; Liu, Bo; Dorgan, John; Habibi, Youssef; Raquez, Jean-Marie; Dubois, Philippe; Gross, Richard A.

    2015-05-01

    Polylactide (PLA) is a commercially produced bio-based thermoplastic with unique properties such as high strength, biocompatibility and biodegradability. However, the low heat deflection temperature (HDT) of PLA significantly impedes its industrial implementation for high-performance applications, requiring the design of PLA-based nanocomposites. Cellulose nanocrystals (CNCs) are derived from cellulose which is highly abundant in nature, non-toxic, biodegradable, and has a low density. CNCs possess many attractive features for use in nano-composites. The main problem of adding hydrophilic CNCs into hydrophobic matrixes is their lack of affinity, leading to phase separation and a decrease in mechanical properties. A one-step method based on both Fischer esterification and acid hydrolysis was used in this work to obtain functionalized and ready-to-use CNCs, with the aim to improve the filler dispersion into the polymeric matrix. The study assesses the reinforcing effect of CNCs on PLA-based materials. CNCs functionalized with acetate (AA-CNCs), lactic acid (LA-CNCs) and unfunctionalized CNCs were synthesized and blends of PLA and these CNCs were prepared by direct melt blending. The corresponding thermomechanical properties were investigated by DMTA. Blends with LA-CNCs possessed the highest storage modulus. Based on these results, blends with up to 20 % LA-CNCs were prepared by direct melt blending and an increase of up to 20°C in the HDT resulted. A decrease in oxygen permeability also resulted from increasing the nano-filler content. This increase in materials properties can potentially expand the applications of PLA based materials.

  14. ABSCISIC ACID-INSENSITIVE 4 negatively regulates flowering through directly promoting Arabidopsis FLOWERING LOCUS C transcription

    Science.gov (United States)

    Shu, Kai; Chen, Qian; Wu, Yaorong; Liu, Ruijun; Zhang, Huawei; Wang, Shengfu; Tang, Sanyuan; Yang, Wenyu; Xie, Qi

    2016-01-01

    During the life cycle of a plant, one of the major biological processes is the transition from the vegetative to the reproductive stage. In Arabidopsis, flowering time is precisely controlled by extensive environmental and internal cues. Gibberellins (GAs) promote flowering, while abscisic acid (ABA) is considered as a flowering suppressor. However, the detailed mechanism through which ABA inhibits the floral transition is poorly understood. Here, we report that ABSCISIC ACID-INSENSITIVE 4 (ABI4), a key component in the ABA signalling pathway, negatively regulates floral transition by directly promoting FLOWERING LOCUS C (FLC) transcription. The abi4 mutant showed the early flowering phenotype whereas ABI4-overexpressing (OE-ABI4) plants had delayed floral transition. Consistently, quantitative reverse transcription–PCR (qRT–PCR) assay revealed that the FLC transcription level was down-regulated in abi4, but up-regulated in OE-ABI4. The change in FT level was consistent with the pattern of FLC expression. Chromatin immunoprecipitation-qPCR (ChIP-qPCR), electrophoretic mobility shift assay (EMSA), and tobacco transient expression analysis showed that ABI4 promotes FLC expression by directly binding to its promoter. Genetic analysis demonstrated that OE-ABI4::flc-3 could not alter the flc-3 phenotype. OE-FLC::abi4 showed a markedly delayed flowering phenotype, which mimicked OE-FLC::WT, and suggested that ABI4 acts upstream of FLC in the same genetic pathway. Taken together, these findings suggest that ABA inhibits the floral transition by activating FLC transcription through ABI4. PMID:26507894

  15. Highly active carbon supported Pd cathode catalysts for direct formic acid fuel cells

    Science.gov (United States)

    Mikolajczuk-Zychora, A.; Borodzinski, A.; Kedzierzawski, P.; Mierzwa, B.; Mazurkiewicz-Pawlicka, M.; Stobinski, L.; Ciecierska, E.; Zimoch, A.; Opałło, M.

    2016-12-01

    One of the drawbacks of low-temperature fuel cells is high price of platinum-based catalysts used for the electroreduction of oxygen at the cathode of the fuel cell. The aim of this work is to develop the palladium catalyst that will replace commonly used platinum cathode catalysts. A series of palladium catalysts for oxygen reduction reaction (ORR) were prepared and tested on the cathode of Direct Formic Acid Fuel Cell (DFAFC). Palladium nanoparticles were deposited on the carbon black (Vulcan) and on multiwall carbon nanotubes (MWCNTs) surface by reduction of palladium(II) acetate dissolved in ethanol. Hydrazine was used as a reducing agent. The effect of functionalization of the carbon supports on the catalysts physicochemical properties and the ORR catalytic activity on the cathode of DFAFC was studied. The supports were functionalized by treatment in nitric acid for 4 h at 80 °C. The structure of the prepared catalysts has been characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), transmission electron microscope (TEM) and cyclic voltammetry (CV). Hydrophilicity of the catalytic layers was determined by measuring contact angles of water droplets. The performance of the prepared catalysts has been compared with that of the commercial 20 wt.% Pt/C (Premetek) catalyst. The maximum power density obtained for the best palladium catalyst, deposited on the surface of functionalized carbon black, is the same as that for the commercial Pt/C (Premetek). Palladium is cheaper than platinum, therefore the developed cathode catalyst is promising for future applications.

  16. Escherichia coli as a fatty acid and biodiesel factory: current challenges and future directions.

    Science.gov (United States)

    Rahman, Ziaur; Rashid, Naim; Nawab, Javed; Ilyas, Muhammad; Sung, Bong Hyun; Kim, Sun Chang

    2016-06-01

    Biodiesel has received widespread attention as a sustainable, environment-friendly, and alternative source of energy. It can be derived from plant, animal, and microbial organisms in the form of vegetable oil, fats, and lipids, respectively. However, biodiesel production from such sources is not economically feasible due to extensive downstream processes, such as trans-esterification and purification. To obtain cost-effective biodiesel, these bottlenecks need to be overcome. Escherichia coli, a model microorganism, has the potential to produce biodiesel directly from ligno-cellulosic sugars, bypassing trans-esterification. In this process, E. coli is engineered to produce biodiesel using metabolic engineering technology. The entire process of biodiesel production is carried out in a single microbial cell, bypassing the expensive downstream processing steps. This review focuses mainly on production of fatty acid and biodiesel in E. coli using metabolic engineering approaches. In the first part, we describe fatty acid biosynthesis in E. coli. In the second half, we discuss bottlenecks and strategies to enhance the production yield. A complete understanding of current developments in E. coli-based biodiesel production and pathway optimization strategies would reduce production costs for biofuels and plant-derived chemicals.

  17. Petroleum Diesel and Biodiesel Fuels Used in a Direct Hydrocarbon Phosphoric Acid Fuel Cell

    Directory of Open Access Journals (Sweden)

    Yuanchen Zhu

    2015-01-01

    Full Text Available The performance of a direct hydrocarbon phosphoric acid fuel cell, PAFC, was investigated using petroleum diesel, biodiesel, and n-hexadecane as the fuels. We believe this is the first study of a fuel cell being operated with petroleum diesel as the fuel at the anode. Degradation in fuel cell performance was observed prior to reaching steady state. The degradation was attributed to a carbonaceous material forming on the surface of the anode. Regardless of the initial degradation, a steady-state operation was achieved with each of the diesel fuels. After treating the anode with water the fuel cell performance recovered. However, the fuel cell performance degraded again prior to obtaining another steady-state operation. There were several observations that were consistent with the suggestion that the carbonaceous material formed from the diesel fuels might be a reaction intermediate necessary for steady-state operation. Finally, the experiments indicated that water in the phosphoric acid electrolyte could be used as the water required for the anodic reaction. The water formed at the cathode could provide the replacement water for the electrolyte, thereby eliminating the need to provide a water feed system for the fuel cell.

  18. Paper-based fluorescence resonance energy transfer assay for directly detecting nucleic acids and proteins.

    Science.gov (United States)

    Li, Hua; Fang, Xueen; Cao, Hongmei; Kong, Jilie

    2016-06-15

    Paper-based fluorescence resonance energy transfer assay (FRET) is gaining great interest in detecting macro-biological molecule. It is difficult to achieve conveniently and fast detection for macro-biological molecule. Herein, a graphene oxide (GO)-based paper chip (glass fiber) integrated with fluorescence labeled single-stranded DNA (ssDNA) for fast, inexpensive and direct detection of biological macromolecules (proteins and nucleic acids) has been developed. In this paper, we employed the Cy3/FAM-labeled ssDNA as the reporter and the GO as quencher and the original glass fiber paper as data acquisition substrates. The chip which was designed and fabricated by a cutting machine is a miniature biosensor that monitors fluorescence recovery from resonance energy transfer. The hybridization assays and fluorescence detection were all simplified, and the surface of the chip did not require immobilization or washing. A Nikon Eclipse was employed as excited resource and a commercial digital camera was employed for capturing digital images. This paper-based microfluidics chip has been applied in the detection of proteins and nucleic acids. The biosensing capability meets many potential requirements for disease diagnosis and biological analysis.

  19. Direct and indirect identification of the formation of hydroxyaluminosilicates in acidic solutions.

    Science.gov (United States)

    Doucet, F J; Rotov, M E; Exley, C

    2001-11-01

    Morin-aluminium fluorescence and membrane filtration were successfully applied to the indirect identification of the formation of hydroxyaluminosilicates (HAS) in acidic solutions of varying pH and of known concentrations of aluminium (Al) and silicic acid (Si(OH)(4)). It was proven to be especially useful in providing evidence of the strong competition between Si(OH)(4) and Al(OH)(3) to condense with hydroxyaluminium templates to form HAS in preference to Al(OH)(3(s)). The aggregation and stability of HAS and Al(OH)(3(s)) were dependent upon both the pH and the [Al] of the solution. The applicability of these indirect techniques was confirmed using the direct observation of HAS in solution by atomic force microscopy (AFM). AFM was also a powerful tool in providing valuable information on the morphology of colloidal HAS of various structures and stoichiometries. The results have provided further confirmation of both the mechanism of HAS formation and the form and stability of HAS in solution. This information is essential to our understanding of the biological availability and hence toxicity of Al in biota, including man.

  20. A randomized direct comparison of the pharmacokinetics and pharmacodynamics of apixaban and rivaroxaban

    Directory of Open Access Journals (Sweden)

    Frost C

    2014-11-01

    Full Text Available Charles Frost,1 Yan Song,1 Yu Chen Barrett,1 Jessie Wang,2 Janice Pursley,3 Rebecca A Boyd,4 Frank LaCreta1 1Exploratory Clinical and Translational Research, 2Exploratory Development Global Biometric Sciences, 3Analytical and Bioanalytical Development, Bristol-Myers Squibb Company, Princeton, NJ, USA; 4Global Innovative Pharma Business Clinical Pharmacology, Pfizer Inc., Groton, CT, USA Background: Currently, there are no direct comparisons of apixaban and rivaroxaban, two new oral direct factor Xa inhibitors approved for management of thromboembolic disorders. Objective: Compare the pharmacokinetics and anti-factor Xa activity (AXA of apixaban and rivaroxaban. Methods: In this randomized, open-label, two-period, two-treatment crossover study, healthy subjects (N=14 received apixaban 2.5 mg twice daily (BID and rivaroxaban 10 mg once daily (QD for 4 days with a ≥4.5-day washout. Plasma samples were obtained for pharmacokinetic and AXA assessments; parameters were calculated using noncompartmental methods. Results: Median time-to-maximum concentration was 2 hours for both compounds, and the mean half-life was 8.7 and 7.9 hours for apixaban and rivaroxaban, respectively. Daily exposure, the area under the curve (AUC(0–24, appeared similar for rivaroxaban (1,094 ng · h/mL and apixaban (935 ng · h/mL, whereas mean peak-to-trough plasma concentration ratio was 3.6-fold greater for rivaroxaban (16.9 than apixaban (4.7. Coefficient of variation for exposure parameters (AUC0–24, Cmax, Cmin was 20%–24% for apixaban versus 29%–46% for rivaroxaban. Peak AXA, AXA AUC(0–24, and AXA fluctuation were ~2.5-, 1.3-, and 3.5-fold higher for rivaroxaban than apixaban, respectively. Trough concentrations and AXA were lower for rivaroxaban (10 ng/mL and 0.17 IU/mL vs 17 ng/mL and 0.24 IU/mL for apixaban, respectively. Rivaroxaban exhibited a steeper concentration–AXA response (slope: 0.0172 IU/ng vs 0.0134 IU/ng for apixaban, P<0.0001. Conclusion

  1. Three-Dimensional Stereoscopic Tracking Velocimetry and Experimental/Numerical Comparison of Directional Solidification

    Science.gov (United States)

    Lee, David; Ge, Yi; Cha, Soyoung Stephen; Ramachandran, Narayanan; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Measurement of three-dimensional (3-D) three-component velocity fields is of great importance in both ground and space experiments for understanding materials processing and fluid physics. The experiments in these fields most likely inhibit the application of conventional planar probes for observing 3-D phenomena. Here, we present the investigation results of stereoscopic tracking velocimetry (STV) for measuring 3-D velocity fields, which include diagnostic technology development, experimental velocity measurement, and comparison with analytical and numerical computation. STV is advantageous in system simplicity for building compact hardware and in software efficiency for continual near-real-time monitoring. It has great freedom in illuminating and observing volumetric fields from arbitrary directions. STV is based on stereoscopic observation of particles-Seeded in a flow by CCD sensors. In the approach, part of the individual particle images that provide data points is likely to be lost or cause errors when their images overlap and crisscross each other especially under a high particle density. In order to maximize the valid recovery of data points, neural networks are implemented for these two important processes. For the step of particle overlap decomposition, the back propagation neural network is utilized because of its ability in pattern recognition with pertinent particle image feature parameters. For the step of particle tracking, the Hopfield neural network is employed to find appropriate particle tracks based on global optimization. Our investigation indicates that the neural networks are very efficient and useful for stereoscopically tracking particles. As an initial assessment of the diagnostic technology performance, laminar water jets with and without pulsation are measured. The jet tip velocity profiles are in good agreement with analytical predictions. Finally, for testing in material processing applications, a simple directional solidification

  2. Extraction of humic acid by coacervate: investigation of direct and back processes.

    Science.gov (United States)

    Ghouas, H; Haddou, B; Kameche, M; Derriche, Z; Gourdon, C

    2012-02-29

    The two aqueous phases extraction process is widely used in environmental clean up of industrial effluents and fine chemical products for their reuse. This process can be made by cloud point of polyethoxylated alcohols and micellar solubilization phenomenon. It is commonly called "coacervate extraction" and is used, in our case, for humic acid extraction from aqueous solution at 100mg/L. The surfactants used are alcohol polyethoxylate and alkylphenol polyethoxylate. Phase diagrams of binary water/surfactant and pseudo-binary are plotted. The extraction results are expressed by the following responses: percentage of solute extracted, E (%), residual concentrations of solute and surfactant in dilute phase (X(s,w), and X(t,w) respectively) and volume fraction of coacervate at equilibrium (ϕ). For each parameter, the experimental results are fitted to empirical equations in three dimensions. The aim of this study is to find out the best compromise between E and ϕC. The comparison between experimental and calculated values allows models validation. Sodium sulfate, cetyltrimethylammonium bromide (CTAB) addition and pH effect are also studied. Finally, the possibility of recycling the surfactant has been proved.

  3. Protodeboronation of ortho- and para-phenol boronic acids and application to ortho and meta functionalization of phenols using boronic acids as blocking and directing groups.

    Science.gov (United States)

    Lee, Chun-Young; Ahn, Su-Jin; Cheon, Cheol-Hong

    2013-12-06

    The first metal-free thermal protodeboronation of ortho- and para-phenol boronic acids in DMSO was developed. The protodeboronation was successfully applied to the synthesis of ortho- and meta-functionalized phenols using the boronic acid moiety as a blocking group and a directing group, respectively. Mechanistic studies suggested that this protodeboronation proceeds through the coordination of water to the boron atom followed by σ-bond metathesis.

  4. Direct analysis of ethylenediaminetetraacetic acid (EDTA) on concrete by reactive-desorption electrospray ionization mass spectrometry.

    Science.gov (United States)

    Lebeau, D; Reiller, P E; Lamouroux, C

    2015-01-01

    Analysis of organic ligands such as ethylenediaminetetraacetic acid (EDTA) is today an important challenge due to their ability to increase the mobility of radionuclides and metals. Reactive desorption electrospray ionization mass spectrometry (reactive-DESI-MS) was used for direct analysis of EDTA on concrete samples. EDTA forms complexes and those with Fe(III) ions are among the most thermodynamically favored. This complexing capacity was used to improve the specific detection of EDTA directly on a concrete matrix by doping the solvent spray of DESI with a solution of FeCl3 to selectively create the complex between EDTA and Fe(III). Thus, EDTA sensitivity was largely improved by two orders of magnitude with reactive-DESI-MS experiments thanks to the specific detection of EDTA as a [EDTA-4H+Fe(III)](-) complex. The proof of principle that reactive DESI can be applied to concrete samples to detect EDTA has been demonstrated. Its capacity for semi-quantitative determination and localization of EDTA under ambient conditions and with very little sample preparation, minimizing sample manipulations and solvent volumes, two important conditions for the development of new methodologies in the field of analytical chemistry, has been shown.

  5. Amperometric microsensor for direct probing of ascorbic acid in human gastric juice.

    Science.gov (United States)

    Hutton, Emily A; Pauliukaitė, Rasa; Hocevar, Samo B; Ogorevc, Božidar; Smyth, Malcolm R

    2010-09-30

    demonstrated the unique featuring of the proposed NiO-RuHCF microsensor under acidic conditions with enhanced sensitivity and stability and proved its promising potentiality for direct amperometric probing of AA at physiological levels in real gastric juice environments.

  6. Comparison of the protein and fatty acid fraction of Balkan donkey and human milk

    Directory of Open Access Journals (Sweden)

    Jasmina Gubić

    2015-07-01

    Full Text Available The aim of this study was to compare the protein and fatty acid fractions of Balkan donkey and human milk in the early lactation stage (40 and 90 day. This study revealed that donkey milk contains αs1-casein (1.38-1.89 g/L and higher concentration of β-casein (0.1-0.55 g/L in comparison to human milk. The concentration of α-lactalbumin increased during the lactation phases from 40 to 90 days in both types of milk. Donkey milk contained β-lactoglobulin in low concentrations which decreased to 90th day of lactation. Donkey milk was particularly rich in two whey proteins, lactoferrin and lysozyme, which were found to have molecular weight of approximately 76 kDa and 14.9-15.4 kDa, respectively. The content of lysozyme in donkey milk ranged from 2.39 to 2.97 g/L, while human milk contained 30-50 times lower concentrations of lysozyme in comparison to donkey milk. Thus, donkey milk contained also a higher concentration of lactoferrin (0.012-0.25 g/L than it was found in the human milk. Lysozyme and lactoferrin content in donkey milk increased during the period from 40th to 90th day of lactation. The percentage of total SFA, MUFA and PUFA was similar in donkey and human milk. The content of essential fatty acids increased during 40-90 days of lactation and was approximately 2.5 times higher in comparison to human milk.

  7. Direct production of biodiesel from high-acid value Jatropha oil with solid acid catalyst derived from lignin

    Directory of Open Access Journals (Sweden)

    Pua Fei-ling

    2011-12-01

    Full Text Available Abstract Background Solid acid catalyst was prepared from Kraft lignin by chemical activation with phosphoric acid, pyrolysis and sulfuric acid. This catalyst had high acid density as characterized by scanning electron microscope (SEM, energy-dispersive x-ray spectrometry (EDX and Brunauer, Emmett, and Teller (BET method analyses. It was further used to catalyze the esterification of oleic acid and one-step conversion of non-pretreated Jatropha oil to biodiesel. The effects of catalyst loading, reaction temperature and oil-to-methanol molar ratio, on the catalytic activity of the esterification were investigated. Results The highest catalytic activity was achieved with a 96.1% esterification rate, and the catalyst can be reused three times with little deactivation under optimized conditions. Biodiesel production from Jatropha oil was studied under such conditions. It was found that 96.3% biodiesel yield from non-pretreated Jatropha oil with high-acid value (12.7 mg KOH/g could be achieved. Conclusions The catalyst can be easily separated for reuse. This single-step process could be a potential route for biodiesel production from high-acid value oil by simplifying the procedure and reducing costs.

  8. Comparison of degradation reactions of Acid Yellow 61 in both oxidation processes of H202/UV and 03

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The comparison of degradation of Acid Yellow 61 as a model dye compound in both oxidation processes of H2 O2/UV and O3 has been studied. When the decolorization rate of Acid Yellow 61 in both reactions presented similar, it was found there are some differences from the results of AOX removal and production of inorganic ions and organic acids. The results reveal that the H2O2/UV has beneficial effect on mineralization than O3 only for degradation of Acid Yellow 61 solution and it is possible for enhancement of method efficiency by taking longer reaction time and addition of high concentration of oxidants.

  9. Complexation efficiency of differently fixed 8-hydroxyquinoline and salicylic acid ligand groups for labile aluminium species determination in soils--comparison of two methods.

    Science.gov (United States)

    Matús, Peter; Kubová, Jana

    2006-07-28

    Two methods utilizing the complexation of labile Al species by 8-hydroxyquinoline (HQN) and salicylic acid (SA) ligand groups were developed for aluminium operationally defined fractionation in acid soils. First, the solid phase extraction (SPE) procedure by a short-term ion-exchange batch reaction with chelating resins Iontosorb Oxin and Iontosorb Salicyl containing both ligand groups was used previously. Second, the 8-hydroxyquinoline, salicylic acid and ammonium salicylate agents with different concentrations by a single extraction protocol were applied in this paper. The flame atomic absorption spectrometry (FAAS) and optical emission spectrometry with inductively coupled plasma were used for aluminium quantification. The comparison of results from both methods show the possibility to supersede the first laborious method for the second simpler one in Al environmental risk assessment. The use of 1% 8-hydroxyquinoline in 2% acetic acid and 0.2% salicylic acid by a single extraction protocol without a need of sample filtration can supersede the SPE procedure in the Al pollution soil monitoring. Finally, the new scheme usable in a laboratory and moreover, directly in a field was proposed for Al fractionation in solid and liquid environmental samples. The labile Al species in soils and sediments are separated after their single leaching by 8-hydroxyquinoline or salicylic acid without a need of sample filtration. The labile Al species in soil solutions and natural waters are separated after their ultrafiltration followed by the SPE procedure with Iontosorb Oxin or Iontosorb Salicyl.

  10. Complexation efficiency of differently fixed 8-hydroxyquinoline and salicylic acid ligand groups for labile aluminium species determination in soils-comparison of two methods

    Energy Technology Data Exchange (ETDEWEB)

    Matus, Peter [Comenius University in Bratislava, Faculty of Natural Sciences, Mlynska dolina, 842 15 Bratislava (Slovakia)]. E-mail: matus@fns.uniba.sk; Kubova, Jana [Comenius University in Bratislava, Faculty of Natural Sciences, Mlynska dolina, 842 15 Bratislava (Slovakia)

    2006-07-28

    Two methods utilizing the complexation of labile Al species by 8-hydroxyquinoline (HQN) and salicylic acid (SA) ligand groups were developed for aluminium operationally defined fractionation in acid soils. First, the solid phase extraction (SPE) procedure by a short-term ion-exchange batch reaction with chelating resins Iontosorb Oxin and Iontosorb Salicyl containing both ligand groups was used previously. Second, the 8-hydroxyquinoline, salicylic acid and ammonium salicylate agents with different concentrations by a single extraction protocol were applied in this paper. The flame atomic absorption spectrometry (FAAS) and optical emission spectrometry with inductively coupled plasma were used for aluminium quantification. The comparison of results from both methods show the possibility to supersede the first laborious method for the second simpler one in Al environmental risk assessment. The use of 1% 8-hydroxyquinoline in 2% acetic acid and 0.2% salicylic acid by a single extraction protocol without a need of sample filtration can supersede the SPE procedure in the Al pollution soil monitoring. Finally, the new scheme usable in a laboratory and moreover, directly in a field was proposed for Al fractionation in solid and liquid environmental samples. The labile Al species in soils and sediments are separated after their single leaching by 8-hydroxyquinoline or salicylic acid without a need of sample filtration. The labile Al species in soil solutions and natural waters are separated after their ultrafiltration followed by the SPE procedure with Iontosorb Oxin or Iontosorb Salicyl.

  11. Towards understanding the puzzling lack of acid geothermal springs in Tibet (China): Insight from a comparison with Yellowstone (USA) and some active volcanic hydrothermal systems

    Science.gov (United States)

    Guo, Qinghai; Kirk Nordstrom, D.; Blaine McCleskey, R.

    2014-11-01

    Explanations for the lack of acid geothermal springs in Tibet are inferred from a comprehensive hydrochemical comparison of Tibetan geothermal waters with those discharged from Yellowstone (USA) and two active volcanic areas, Nevado del Ruiz (Colombia) and Miravalles (Costa Rica) where acid springs are widely distributed and diversified in terms of geochemical characteristic and origin. For the hydrothermal areas investigated in this study, there appears to be a relationship between the depths of magma chambers and the occurrence of acid, chloride-rich springs formed via direct magmatic fluid absorption. Nevado del Ruiz and Miravalles with magma at or very close to the surface (less than 1-2 km) exhibit very acidic waters containing HCl and H2SO4. In contrast, the Tibetan hydrothermal systems, represented by Yangbajain, usually have fairly deep-seated magma chambers so that the released acid fluids are much more likely to be fully neutralized during transport to the surface. The absence of steam-heated acid waters in Tibet, however, may be primarily due to the lack of a confining layer (like young impermeable lavas at Yellowstone) to separate geothermal steam from underlying neutral chloride waters and the possible scenario that the deep geothermal fluids below Tibet carry less H2S than those below Yellowstone.

  12. Sulfonated reduced graphene oxide as a highly efficient catalyst for direct amidation of carboxylic acids with amines using ultrasonic irradiation.

    Science.gov (United States)

    Mirza-Aghayan, Maryam; Tavana, Mahdieh Molaee; Boukherroub, Rabah

    2016-03-01

    Sulfonated reduced graphene oxide nanosheets (rGO-SO3H) were prepared by grafting sulfonic acid-containing aryl radicals onto chemically reduced graphene oxide (rGO) under sonochemical conditions. rGO-SO3H catalyst was characterized by Fourier-transform infrared (FT-IR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and X-ray photoelectron spectroscopy (XPS). rGO-SO3H catalyst was successfully applied as a reusable solid acid catalyst for the direct amidation of carboxylic acids with amines into the corresponding amides under ultrasonic irradiation. The direct sonochemical amidation of carboxylic acid takes place under mild conditions affording in good to high yields (56-95%) the corresponding amides in short reaction times.

  13. Direct tandem mass spectrometric analysis of amino acids in plasma using fluorous derivatization and monolithic solid-phase purification.

    Science.gov (United States)

    Tamashima, Erina; Hayama, Tadashi; Yoshida, Hideyuki; Imakyure, Osamu; Yamaguchi, Masatoshi; Nohta, Hitoshi

    2015-11-10

    In this study, we developed a novel direct tandem mass spectrometric method for rapid and accurate analysis of amino acids utilizing a fluorous derivatization and purification technique. Amino acids were perfluoroalkylated with 2H,2H,3H,3H-perfluoroundecan-1-al in the presence of 2-picoline borane via reductive amination. The derivatives were purified by perfluoroalkyl-modified silica-based monolithic solid-phase extraction (monolithic F-SPE), and directly analyzed by tandem mass spectrometry using electrospray ionization without liquid chromatographic separation. The perfluoroalkyl derivatives could be sufficiently distinguished from non-fluorous compounds, i.e. the biological matrix, due to their fluorous interaction. Thus, rapid and accurate determination of amino acids was accomplished. The method was validated with human plasma samples and applied to the analysis of amino acids in the plasma of mice with maple syrup urine disease or phenylketonuria.

  14. Microbial Quality and Direct PCR Identification of Lactic Acid Bacteria and Nonpathogenic Staphylococci from Artisanal Low-Acid Sausages

    OpenAIRE

    Aymerich, T.; B. Martín; Garriga, M.; Hugas, M

    2005-01-01

    Detection of six species of lactic acid bacteria and six species of gram-positive catalase-positive cocci from low-acid fermented sausages (fuets and chorizos) was assessed by species-specific PCR. Without enrichment, Lactobacillus sakei and Lactobacillus curvatus were detected in 11.8% of the samples, and Lactobacillus plantarum and Staphylococcus xylosus were detected in 17.6%. Enriched samples allowed the detection of L. sakei and S. xylosus in all of the samples (100%) and of Enterococcus...

  15. Direct comparison of phase-sensitive vibrational sum frequency generation with maximum entropy method: case study of water.

    Science.gov (United States)

    de Beer, Alex G F; Samson, Jean-Sebastièn; Hua, Wei; Huang, Zishuai; Chen, Xiangke; Allen, Heather C; Roke, Sylvie

    2011-12-14

    We present a direct comparison of phase sensitive sum-frequency generation experiments with phase reconstruction obtained by the maximum entropy method. We show that both methods lead to the same complex spectrum. Furthermore, we discuss the strengths and weaknesses of each of these methods, analyzing possible sources of experimental and analytical errors. A simulation program for maximum entropy phase reconstruction is available at: http://lbp.epfl.ch/.

  16. Methyl phosphate formation as a major degradation mode of direct methanol fuel cells with phosphoric acid based electrolytes

    DEFF Research Database (Denmark)

    Aili, David; Vassiliev, Anton; Jensen, Jens Oluf

    2015-01-01

    Phosphoric acid and phosphoric acid doped polymer membranes are widely used as electrolytes in hydrogen based fuel cells operating at elevated temperatures. Such electrolytes have been explored for direct oxidation of methanol to further increase the versatility of the systems, however......, with demonstrated lifetimes of only a few days to weeks. In this work the methyl phosphate formation from the acid and methanol is identified and proposed to be a major mechanism for the cell degradation. Proton conductivity and fuel cell durability tests validate the mechanism at high methanol contents....

  17. Biotechnological Production of Docosahexaenoic Acid Using Aurantiochytrium limacinum: Carbon Sources Comparison And Growth Characterization

    Directory of Open Access Journals (Sweden)

    Sergi Abad

    2015-12-01

    Full Text Available Aurantiochytrium limacinum, a marine heterotrophic protist/microalga has shown interesting yields of docosahexaenoic acid (DHA when cultured with different carbon sources: glucose, pure and crude glycerol. A complete study in a lab-scale fermenter allowed for the characterization and comparison of the growth kinetic parameters corresponding to each carbon source. Artificial Marine Medium (AMM with glucose, pure and crude glycerol offered similar biomass yields. The net growth rates (0.10–0.12 h−1, biomass (0.7–0.8 g cells/g Substrate and product (0.14–0.15 g DHA/g cells yields, as well as DHA productivity were similar using the three carbon sources. Viable potential applications to valorize crude glycerol are envisioned to avoid an environmental problem due to the excess of byproduct.

  18. Assessment and comparison of 100-MW coal gasification phosphoric acid fuel cell power plants

    Science.gov (United States)

    Lu, Cheng-Yi

    1988-01-01

    One of the advantages of fuel cell (FC) power plants is fuel versatility. With changes only in the fuel processor, the power plant will be able to accept a variety of fuels. This study was performed to design process diagrams, evaluate performance, and to estimate cost of 100 MW coal gasifier (CG)/phosphoric acid fuel cell (PAFC) power plant systems utilizing coal, which is the largest single potential source of alternate hydrocarbon liquids and gases in the United States, as the fuel. Results of this study will identify the most promising integrated CG/PAFC design and its near-optimal operating conditions. The comparison is based on the performance and cost of electricity which is calculated under consistent financial assumptions.

  19. Direct anodic hydrochloric acid and cathodic caustic production during water electrolysis

    Science.gov (United States)

    Lin, Hui-Wen; Cejudo-Marín, Rocío; Jeremiasse, Adriaan W.; Rabaey, Korneel; Yuan, Zhiguo; Pikaar, Ilje

    2016-02-01

    Hydrochloric acid (HCl) and caustic (NaOH) are among the most widely used chemicals by the water industry. Direct anodic electrochemical HCl production by water electrolysis has not been successful as current commercially available electrodes are prone to chlorine formation. This study presents an innovative technology simultaneously generating HCl and NaOH from NaCl using a Mn0.84Mo0.16O2.23 oxygen evolution electrode during water electrolysis. The results showed that protons could be anodically generated at a high Coulombic efficiency (i.e. ≥ 95%) with chlorine formation accounting for 3 ~ 5% of the charge supplied. HCl was anodically produced at moderate strengths at a CE of 65 ± 4% together with a CE of 89 ± 1% for cathodic caustic production. The reduction in CE for HCl generation was caused by proton cross-over from the anode to the middle compartment. Overall, this study showed the potential of simultaneous HCl and NaOH generation from NaCl and represents a major step forward for the water industry towards on-site production of HCl and NaOH. In this study, artificial brine was used as a source of sodium and chloride ions. In theory, artificial brine could be replaced by saline waste streams such as Reverse Osmosis Concentrate (ROC), turning ROC into a valuable resource.

  20. Direct ab initio molecular dynamics study of the two photodissociation channels of formic acid

    Energy Technology Data Exchange (ETDEWEB)

    Kurosaki, Yuzuru; Yokoyama, Keiichi; Teranishi, Yoshiaki

    2005-01-31

    A total of {approx}1200 trajectories have been integrated for the two photodissociation channels of formic acid, HCOOH {yields} H{sub 2}O + CO (1) and HCOOH {yields} CO{sub 2} + H{sub 2} (2), which occur with 248 and 193 nm photons, using the direct ab initio molecular dynamics method at the RMP2(full)/cc-pVDZ level of theory. It was found that the percentage of the energy distributed to a relative translational mode in reaction is much larger than that in reaction . This is mainly due to the difference in the geometry of transition state (TS); the H{sub 2}O geometry in the TS of reaction was predicted to significantly deviate from the equilibrium one, whereas the CO{sub 2} and H{sub 2} geometries in the TS of reaction were found to be more similar to their equilibrium ones. It was also found that the product diatomic molecules, CO and H{sub 2}, are both vibrationally and rotationally excited. The calculated relative population of the vibrationally excited CO for the 248 nm photodissociation was consistent with experiment.

  1. Direct Analysis of Leucine and Its Metabolites β-Hydroxy-β-methylbutyric Acid, α-Ketoisocaproic Acid, and α-Hydroxyisocaproic Acid in Human Breast Milk by Liquid Chromatography-Mass Spectrometry.

    Science.gov (United States)

    Ehling, Stefan; Reddy, Todime M

    2015-09-02

    A direct, quantitative, and confirmatory method based on stable isotope dilution liquid chromatography-mass spectrometry was developed and validated for the analysis of leucine and metabolites β-hydroxy-β-methylbutyric acid (HMB), α-ketoisocaproic acid (KIC), and α-hydroxyisocaproic acid (HICA) in human breast milk. Chromatographic resolution was achieved between isobaric leucine and isoleucine. Accuracy and intermediate precision were 89-117% and breast milk composition and its effect on protein turnover in developing infants.

  2. Achievement Goal Orientations and Adolescents’ Subjective Well-Being in School: The Mediating Roles of Academic Social Comparison Directions

    Science.gov (United States)

    Tian, Lili; Yu, Tingting; Huebner, E. Scott

    2017-01-01

    The purpose of this study was to examine the multiple mediational roles of academic social comparison directions (upward academic social comparison and downward academic social comparison) on the relationships between achievement goal orientations (i.e., mastery goals, performance-approach goals, and performance-avoidance goals) and subjective well-being (SWB) in school (school satisfaction, school affect) in adolescent students in China. A total of 883 Chinese adolescent students (430 males; Mean age = 12.99) completed a multi-measure questionnaire. Structural equation modeling was used to examine the hypotheses. Results indicated that (1) mastery goal orientations and performance-approach goal orientations both showed a statistically significant, positive correlation with SWB in school whereas performance-avoidance goal orientations showed a statistically significant, negative correlation with SWB in school among adolescents; (2) upward academic social comparisons mediated the relation between the three types of achievement goal orientations (i.e., mastery goals, performance-approach goals, and performance-avoidance goals) and SWB in school; (3) downward academic social comparisons mediated the relation between mastery goal orientations and SWB in school as well as the relation between performance-avoidance goal orientations and SWB in school. The findings suggest possible important cultural differences in the antecedents of SWB in school in adolescent students in China compared to adolescent students in Western nations. PMID:28197109

  3. Role of Lewis acid additives in a palladium catalyzed directed C-H functionalization reaction of benzohydroxamic acid to isoxazolone.

    Science.gov (United States)

    Athira, C; Sunoj, Raghavan B

    2016-12-20

    Metallic salts as well as protic additives are widely employed in transition metal catalyzed C-H bond functionalization reactions to improve the efficiency of catalytic protocols. In one such example, ZnCl2 and pivalic acid are used as additives in a palladium catalyzed synthesis of isoxazolone from a readily available benzohydroxamic acid under one pot conditions. In this article, we present some important mechanistic insights into the role of ZnCl2 and pivalic acid, gained by using density functional theory (M06) computations. Two interesting modes of action of ZnCl2 are identified in various catalytic steps involved in the formation of isoxazolone. The conventional Lewis acid coordination wherein zinc chloride (ZnCl2·(DMA)) binds to the carbonyl group is found to be more favored in the C-H activation step. However, the participation of a hetero-bimetallic Pd-Zn species is preferred in reductive elimination leading to Caryl-N bond formation. Pivalic acid helps in relay proton transfer in C-H bond activation through a cyclometallation deprotonation (CMD) process. The explicit inclusion of ZnCl2 and solvent N,N-dimethyl acetamide (DMA) stabilizes the transition state and also helps reduce the activation barrier for the C-H bond activation step. The electronic communication between the two metal species is playing a crucial role in stabilizing the Caryl-N bond formation transition state through a Pd-Zn hetero-bimetallic interaction.

  4. Protic acid immobilized on solid support as an extremely efficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols.

    Science.gov (United States)

    Chakraborti, Asit K; Singh, Bavneet; Chankeshwara, Sunay V; Patel, Alpesh R

    2009-08-21

    A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO(4)-SiO(2)). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C(10)) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H(2)SO(4), HBr, TfOH, HBF(4), and TFA that were adsorbed on silica gel were less effective compared to HClO(4)-SiO(2) following the order HClO(4)-SiO(2) > H(2)SO(4)-SiO(2) > HBr-SiO(2) > TfOH-SiO(2) > HBF(4)-SiO(2) approximately TFA-SiO(2). When HClO(4) was immobilized on other solid supports the catalytic efficiency followed the order HClO(4)-SiO(2) > HClO(4)-K10 > HClO(4)-Al(2)O(3) (neutral) > HClO(4)-Al(2)O(3) (acidic) > HClO(4)-Al(2)O(3) (basic).

  5. Polymerase-directed synthesis of C5-ethynyl locked nucleic acids

    DEFF Research Database (Denmark)

    Veedu, Rakesh N; Burri, Harsha Vardhan Reddy; Kumar, Pawan;

    2010-01-01

    Modified nucleic acids have considerable potential in nanobiotechnology for the development of nanomedicines and new materials. Locked nucleic acid (LNA) is one of the most prominent nucleic acid analogues reported so far and we herein for the first time report the enzymatic incorporation of LNA...

  6. Direct Double Electrophilic Fluorination of Allenoic Acids and Tosylamides to Give 1,1-Difluoroallylic Heterocyclic Compounds%Direct Double Electrophilic Fluorination of Allenoic Acids and Tosylamides to Give 1,1-Difluoroallylic Heterocyclic Compounds

    Institute of Scientific and Technical Information of China (English)

    崔海峰; 柴卓; 陆颖鹏; 李鹏; 赵刚; 朱士正

    2011-01-01

    A novel and facile preparation of l,l-difluoroallyl substituted five-membered lactones or pyrrolidines in mod- erate yields through direct double electrophilic fluorination of 4,5-allenoic acids or tosylamides with SelectfluorTM F-TEAD-BF4 is described.

  7. Direct comparisons of GOMOS and SAGE III NO3 vertical profiles

    Directory of Open Access Journals (Sweden)

    J. R. Moore

    2012-02-01

    Full Text Available In this paper we present first global comparisons between the two unique satellite-borne data sets of NO3 vertical profiles retrieved from the GOMOS (Global Ozone Monitoring by the Occultation of Stars stellar occultations and the SAGE III (Stratospheric Aerosols and Gas Experiment lunar occultations. The comparison results indicate that between the altitudes 25 km and 45 km the median difference between these two data sets is within ±25%. The study of zonal median profiles shows agreement between these data sets. The agreement is at its best in tropics and slightly deviating towards the poles.

  8. Direct incorporation of fatty acids into microbial phospholipids in soils: Position-specific labeling tells the story

    Science.gov (United States)

    Dippold, Michaela A.; Kuzyakov, Yakov

    2016-02-01

    Fatty acids have been used as plant and microbial biomarkers, and knowledge about their transformation pathways in soils and sediments is crucial for interpreting fatty acid signatures, especially because the formation, recycling and decomposition processes are concurrent. We analyzed the incorporation of free fatty acids into microbial fatty acids in soil by coupling position-specific 13C labeling with compound-specific 13C analysis. Position-specifically and uniformly 13C labeled palmitate were applied in an agricultural Luvisol. Pathways of fatty acids were traced by analyzing microbial utilization of 13C from individual molecule positions of palmitate and their incorporation into phospholipid fatty acids (PLFA). The fate of palmitate 13C in the soil was characterized by the main pathways of microbial fatty acid metabolism: Odd positions (C-1) were preferentially oxidized to CO2 in the citric acid cycle, whereas even positions (C-2) were preferentially incorporated into microbial biomass. This pattern is a result of palmitate cleavage to acetyl-CoA and its further use in the main pathways of C metabolism. We observed a direct, intact incorporation of more than 4% of the added palmitate into the PLFA of microbial cell membranes, indicating the important role of palmitate as direct precursor for microbial fatty acids. Palmitate 13C was incorporated into PLFA as intact alkyl chain, i.e. the C backbone of palmitate was not cleaved, but palmitate was incorporated either intact or modified (e.g. desaturated, elongated or branched) according to the fatty acid demand of the microbial community. These modifications of the incorporated palmitate increased with time. Future PLFA studies must therefore consider the recycling of existing plant and microbial-derived fatty acids. This study demonstrates the intact uptake and recycling of free fatty acids such as palmitate in soils, as well as the high turnover and transformation of cellular PLFA. Knowledge about the intact

  9. Comparison of "Direct" and "Indirect" Nuclear Cystography in the Diagnosis of Vesicoureteric Reflux

    OpenAIRE

    Khriesat Imad; Khriesat Sameer; Hazza Issa

    2001-01-01

    This study was undertaken to compare "direct" and "indirect" nuclear cystography for the detection of vesicoureteral reflux (VUR). Forty-five children (15 males and 30 females), ranging in age from 5 months to 10 years, were studied at the King Hussein Medical Center, Amman, Jordan between January 1998 and December 1999, using both direct (catheter) and indirect techniques of nuclear cystography (NC). Of the 82 ureters that could be compared, 32 ureters were positive for VUR on the direct tec...

  10. Comparison of direct and indirect plasma oxidation of NO combined with oxidation by catalyst

    DEFF Research Database (Denmark)

    Jogi, Indrek; Stamate, Eugen; Irimiea, Cornelia

    2015-01-01

    Direct and indirect plasma oxidation of NOx was tested in a medium-scale test-bench at gas flows of 50 slm (3 m(3)/h). For direct plasma oxidation the synthetic flue gas was directed through a stacked DBD reactor. For indirect plasma oxidation, a DBD reactor was used to generate ozone from pure O-2...... of the DBD reactor decreased the long-term efficiency of direct plasma oxidation. At the same time, the efficiency of indirect oxidation increased at elevated reactor temperatures. Additional experiments were carried out to investigate the improvement of indirect oxidation by the introduction of catalyst...

  11. Metabolism of chicoric acid by rat liver microsomes and bioactivity comparisons of chicoric acid and its metabolites.

    Science.gov (United States)

    Liu, Qian; Wang, Yutang; Xiao, ChunXia; Wu, Wanqiang; Liu, Xuebo

    2015-06-01

    Chicoric acid has recently become a hot research topic due to its potent bioactivities. However, there are few studies relevant to this acid's pharmacokinetic characteristics and the pharmacological activities of its metabolites. To compare the abilities of chicoric acid and its metabolites in scavenging free radicals and their effects on the viability of 3T3-L1 preadipocytes, an in vitro study of the metabolism of chicoric acid in rat liver microsomes was performed using liquid tandem mass spectrometry (HPLC-MS/MS). The results indicated that caffeic acid and caftaric acid were the hepatic phase I metabolites of chicoric acid. These three compounds had strong capacities for scavenging free radicals and had been demonstrated to increase intracellular ROS levels in 3T3-L1 preadipocytes, thereby reducing cell vitality. Finally, the pharmacological activities of chicoric acid were significantly stronger than those of its metabolites within a certain concentration range.

  12. The proteolytic system of lactic acid bacteria revisited: a genomic comparison

    Directory of Open Access Journals (Sweden)

    Renckens Bernadet

    2010-01-01

    Full Text Available Abstract Background Lactic acid bacteria (LAB are a group of gram-positive, lactic acid producing Firmicutes. They have been extensively used in food fermentations, including the production of various dairy products. The proteolytic system of LAB converts proteins to peptides and then to amino acids, which is essential for bacterial growth and also contributes significantly to flavor compounds as end-products. Recent developments in high-throughput genome sequencing and comparative genomics hybridization arrays provide us with opportunities to explore the diversity of the proteolytic system in various LAB strains. Results We performed a genome-wide comparative genomics analysis of proteolytic system components, including cell-wall bound proteinase, peptide transporters and peptidases, in 22 sequenced LAB strains. The peptidase families PepP/PepQ/PepM, PepD and PepI/PepR/PepL are described as examples of our in silico approach to refine the distinction of subfamilies with different enzymatic activities. Comparison of protein 3D structures of proline peptidases PepI/PepR/PepL and esterase A allowed identification of a conserved core structure, which was then used to improve phylogenetic analysis and functional annotation within this protein superfamily. The diversity of proteolytic system components in 39 Lactococcus lactis strains was explored using pangenome comparative genome hybridization analysis. Variations were observed in the proteinase PrtP and its maturation protein PrtM, in one of the Opp transport systems and in several peptidases between strains from different Lactococcus subspecies or from different origin. Conclusions The improved functional annotation of the proteolytic system components provides an excellent framework for future experimental validations of predicted enzymatic activities. The genome sequence data can be coupled to other "omics" data e.g. transcriptomics and metabolomics for prediction of proteolytic and flavor

  13. Identification of new flavone-8-acetic acid metabolites using mouse microsomes and comparison with human microsomes.

    Science.gov (United States)

    Pham, Minh Hien; Auzeil, Nicolas; Regazzetti, Anne; Dauzonne, Daniel; Dugay, Annabelle; Menet, Marie-Claude; Scherman, Daniel; Chabot, Guy G

    2007-11-01

    Flavone-8-acetic acid (FAA) is a potent anticancer agent in mouse but has not shown activity in humans. Because FAA metabolism could play a role in this interspecies difference, our aim was to identify the metabolites formed in vitro using mouse microsomes compared with those in human microsomes. Mouse microsomes produced six metabolites as detected by reversed-phase high-performance liquid chromatography-mass spectrometry (MS). Three metabolites were identified as the 3'-, 4'-, or 6-hydroxy-FAA, by comparison with retention times and UV and MS spectra of standards. Two metabolites presented a molecular weight of 296 (FAA = 280) indicating the presence of one oxygen but did not correspond to any monohydroxylated FAA derivative. These two metabolites were identified as epoxides because they were sensitive to epoxide hydrolase. The position of the oxygen was determined by the formation of the corresponding phenols under soft acidic conditions: one epoxide yielded the 3'- and 4'-hydroxy-FAA, thus corresponding to the 3',4'-epoxy-FAA, whereas the other epoxide yielded 5- and 6-hydroxy-FAA, thus identifying the 5,6-epoxy-FAA. The last metabolite was assigned to the 3',4'-dihydrodiol-FAA because of its molecular weight (314) and sulfuric acid dehydration that indicated that the 3'- and 4'-positions were involved. Compared with mouse microsomes, human microsomes (2 pools and 15 individual microsomes) were unable to metabolize FAA to a significant extent. In conclusion, we have identified six new FAA metabolites formed by mouse microsomes, whereas human microsomes could not metabolize this flavonoid to a significant extent. The biological importance of the new metabolites identified herein remains to be evaluated.

  14. Cloning and expression of Chromobacterium violaceum phenylalanine hydroxylase in Escherichia coli and comparison of amino acid sequence with mammalian aromatic amino acid hydroxylases.

    Science.gov (United States)

    Onishi, A; Liotta, L J; Benkovic, S J

    1991-10-05

    The complete amino acid sequence (296 amino acids) of Chromobacterium violaceum phenylalanine hydroxylase (PAH) was determined by nucleotide analysis of a DNA clone isolated using both a synthetic oligonucleotide probe based on the NH2-terminal amino acid sequence and an antibody against this enzyme. The ApaL I fragment (approximately 1.9 kilobase pairs) containing the entire PAH gene was subcloned in pBluescript II and induced by isopropyl-beta-D-thiogalactopyranoside. In order to eliminate fusion proteins the XbaI/ClaI fragment which contained the PAH gene from the Bluescript construct was subcloned into pMAC 5-8 containing the TAC promoter. The recombinant protein reacts with antibody raised to authentic C. violaceum PAH and its NH2-terminal 20-amino acid sequence and COOH-terminal amino acid residue were identical with the wild-type protein. Key physical and chemical characteristics of the recombinant protein, i.e. its copper content and Michaelis-Menten parameters, were the same as wild-type. Comparison of amino acid sequences revealed a highly conserved region between C. violaceum PAH and three different mammalian aromatic amino acid hydroxylases. This conserved area may well be a catalytically important domain of these pterin- and metal-requiring aromatic amino acid hydroxylases. The over-expression of C. violaceum PAH in Escherichia coli will facilitate the analysis of the enzyme mechanism by various spectroscopic methods.

  15. Direct analysis of intact glycidyl fatty acid esters in edible oils using gas chromatography-mass spectrometry

    NARCIS (Netherlands)

    van Steenbergen, H.; Hrnčiřík, K.; Ermacora, A.; de Koning, S.; Janssen, H.-G.

    2013-01-01

    Glycidyl esters (GE), fatty acid esters of glycidol, are process contaminants formed during edible oil processing. A novel direct method for the determination of intact GE in oils and fats based on gas chromatography-mass spectrometry (GC-MS) is presented. The method consists of a simple extraction

  16. Direct starch fermentation to L-lactic acid by a newly isolated thermophilic strain, Bacillus sp. MC-07.

    Science.gov (United States)

    Poudel, Pramod; Tashiro, Yukihiro; Miyamoto, Hirokuni; Miyamoto, Hisashi; Okugawa, Yuki; Sakai, Kenji

    2015-01-01

    A newly isolated Bacillus sp. MC-07 showed 99.2 % 16S rRNA gene sequence similarity with the Bacillus thermoamylovorans LMG 18084(T). It demonstrated optimum and maximum growth temperatures of 50 and 62 °C, respectively. The ability of MC-07 to produce optically pure L-lactic acid via direct fermentation of starch without enzymatic hydrolysis was investigated at different pH values (6.0-8.0) by intermittent adjustments every 12 h. During batch fermentation in mineral salt medium containing 0.001 % yeast extract at pH 7.0, 20 g/L of soluble starch was utilized to produce 16.6 g/L L-lactic acid at 50 °C within 24 h of fermentation, with 100 % optical purity, 92.1 % lactic acid selectivity, and an L-lactic acid yield of 0.977 g/g. Direct starch fermentation at pHs 6.0, 6.5, 7.5, and 8.0 resulted in considerably lower concentrations of lactic acid than did at pH 7.0. Compared with B. thermoamylovorans LMG 18084(T), the ability of strain MC-07 to produce L-lactic acid was superior.

  17. Direct hepatic differentiation of mouse embryonic stem cells induced by valproic acid and cytokines

    Institute of Scientific and Technical Information of China (English)

    Xue-Jun Dong; Guo-Rong Zhang; Qing-Jun Zhou; Ruo-Lang Pan; Ye Chen; Li-Xin Xiang; Jian-Zhong Shao

    2009-01-01

    AIM: To develop a protocol for direct hepatic lineage differentiation from early developmental progenitors to a population of mature hepatocytes. METHODS: Hepatic progenitor cells and then mature hepatocytes from mouse embryonic stem (ES) cells were obtained in a sequential manner, induced by valproic acid (VPA) and cytokines (hepatocyte growth factor, epidermal growth factor and insulin). Morphological changes of the differentiated cells were examined by phase-contrast microscopy and electron microscopy. Reverse transcription polymerase chain reaction and immunocytochemical analyses were used to evaluate the gene expression profiles of the VPA-induced hepatic progenitors and the hepatic progenitor-derived hepatocytes. Glycogen storage, cytochrome P450 activity, transplantation assay, differentiation of bile duct-like structures and tumorigenic analyses were performed for the functional identification of the differentiated cells. Furthermore, FACS and electron microscopy were used for the analyses of cell cycle profile and apoptosis in VPA-induced hepatic differentiated cells. RESULTS: Based on the combination of VPA and cytokines, mouse ES cells differentiated into a uniform and homogeneous cell population of hepatic progenitor cells and then matured into functional hepatocytes. The progenitor population shared several characteristics with ES cells and hepatic stem/progenitor cells, and represented a novel progenitor cell between ES and hepatic oval cells in embryonic development. The differentiated hepatocytes from progenitor cells shared typical characteristics with mature hepatocytes, including the patterns of gene expression, immunological markers, in vitro hepatocyte functions and in vivo capacity to restore acute-damaged liver function. In addition, the differentiation of hepatic progenitor cells from ES cells was accompanied by significant cell cycle arrest and selective survival of differentiating cells towards hepatic lineages. CONCLUSION: Hepatic cells

  18. Comparison of "Direct" and "Indirect" Nuclear Cystography in the Diagnosis of Vesicoureteric Reflux

    Directory of Open Access Journals (Sweden)

    Khriesat Imad

    2001-01-01

    Full Text Available This study was undertaken to compare "direct" and "indirect" nuclear cystography for the detection of vesicoureteral reflux (VUR. Forty-five children (15 males and 30 females, ranging in age from 5 months to 10 years, were studied at the King Hussein Medical Center, Amman, Jordan between January 1998 and December 1999, using both direct (catheter and indirect techniques of nuclear cystography (NC. Of the 82 ureters that could be compared, 32 ureters were positive for VUR on the direct technique while only 20 ureters showed VUR on the indirect technique (sensitivity 62%. Nine ureters, which did not show VUR on the direct cystogram, were read as positive on the indirect cystogram (specificity 82%. The false positive results of indirect nuclear cystogram make it invalid for VUR screening program, while the ease of assessment and low radiation dose from the direct NC has made this the recommended test for screening and follow-up of VUR.

  19. Comparison of "direct" and "indirect" nuclear cystography in the diagnosis of vesicoureteric reflux.

    Science.gov (United States)

    Khriesat, I; Khriesat, S; Hazza, I

    2001-01-01

    This study was undertaken to compare "direct" and "indirect" nuclear cystography for the detection of vesicoureteral reflux (VUR). Forty-five children (15 males and 30 females), ranging in age from 5 months to 10 years, were studied at the King Hussein Medical Center, Amman, Jordan between January 1998 and December 1999, using both direct (catheter) and indirect techniques of nuclear cystography (NC). Of the 82 ureters that could be compared, 32 ureters were positive for VUR on the direct technique while only 20 ureters showed VUR on the indirect technique (sensitivity 62%). Nine ureters, which did not show VUR on the direct cystogram, were read as positive on the indirect cystogram (specificity 82%). The false positive results of indirect nuclear cystogram make it invalid for VUR screening program, while the ease of assessment and low radiation dose from the direct NC has made this the recommended test for screening and follow-up of VUR.

  20. Pseudoephedrine-Directed Asymmetric α-Arylation of α-Amino Acid Derivatives.

    Science.gov (United States)

    Atkinson, Rachel C; Fernández-Nieto, Fernando; Mas Roselló, Josep; Clayden, Jonathan

    2015-07-27

    Available α-amino acids undergo arylation at their α position in an enantioselective manner on treatment with base of N'-aryl urea derivatives ligated to pseudoephedrine as a chiral auxiliary. In situ silylation and enolization induces diastereoselective migration of the N'-aryl group to the α position of the amino acid, followed by ring closure to a hydantoin with concomitant explulsion of the recyclable auxiliary. The hydrolysis of the hydantoin products provides derivatives of quaternary amino acids. The arylation avoids the use of heavy-metal additives, and is successful with a range of amino acids and with aryl rings of varying electronic character.

  1. The structure and validity of directional measures of appearance social comparison among emerging adults in China.

    Science.gov (United States)

    Liao, Jun; Jackson, Todd; Chen, Hong

    2014-09-01

    We evaluated the structure and validity of the Upward Appearance Comparison Scale (UPACS) and Downward Appearance Comparison Scale (DACS) (O'Brien et al., 2009) in Chinese samples. In Study 1, principal component analysis on an initial sample (427 women, 123 men) and confirmatory factor analysis on another sample (447 women, 121 men) found that a 15-item, two component model had the best overall fit. Derived components had moderate correlations with most conceptually related measures and low correlations with less conceptually related indices. Study 2 participants (310 women, 201 men) completed the UPACS and DACS as well as measures of disordered eating, fatness concern, and negative affect; they were re-assessed one year later. Baseline UPACS scores predicted changes in disordered eating for women and fatness concerns for men, independent of initial disturbances, but DACS responses were not related to outcomes. Findings highlighted the potential utility of derived UPACS and DACS within a Chinese context.

  2. New Regionalism and the European Union. Dialogues, Comparisons and New Research Directions

    OpenAIRE

    Warleigh-Lack, A; Robinson, N.; Rosamond, B

    2011-01-01

    The debates on regionalism have been polarized between European Union (EU) scholars and non-EU scholars, with the assumption being that regionalism within the EU and other regions of the world are quite distinct, with little to be learnt from dialogue with each other. This book challenges such assumptions and calls for a genuine debate between scholars of regionalism. This book demonstrates that more can and needs to be learned about regional integration all over the world through comparison ...

  3. Consumers' willingness to pay for beef direct sales. A regional comparison across the Pyrenees.

    Science.gov (United States)

    Sanjuán, Ana I; Resano, Helena; Zeballos, Gabriela; Sans, Pierre; Panella-Riera, Nuria; Campo, M Mar; Khliji, Saoussan; Guerrero, Ana; Oliver, M Angels; Sañudo, Carlos; Santolaria, Pilar

    2012-06-01

    Willingness to pay (WTP) for direct market of beef is investigated in two Spanish and two French regions located on both sides of the Pyrenees. Given the novelty of this distribution system, especially in Spain, a contingent valuation approach is undertaken, and a double-bounded model is estimated. Different patterns of awareness, use and WTP are found across regions. Likewise, the profile of current and potential users of direct sale chains is investigated. Experience in the different stages involved from choice to final consumption of beef, intensity of varied beef consumption, familiarity with direct market of food in general, and beef in particular, are some of the relevant factors to explain WTP and the probability of getting engaged into a direct distribution system of beef.

  4. Comparison of vector velocity imaging using directional beamforming and transverse oscillation for a convex array transducer

    Science.gov (United States)

    Jensen, Jørgen Arendt

    2014-03-01

    Vector velocity imaging can reveal both the magnitude and direction of the blood velocity. Several techniques have been suggested for estimating the velocity, and this paper compares the performance for directional beam-forming and transverse oscillation (TO) vector flow imaging (VFI). Data have been acquired using the SARUS experimental ultrasound scanner connected to a BK 8820e (BK Medical, Herlev, Denmark) convex array probe with 192 active elements. A duplex sequence with 129 B-mode emissions interleaved with 129 flow emissions has been made. The flow was generated in a recirculating flow rig with a stationary, laminar flow, and the volume flow was measured by a MAG 3000 (Danfos, Sønderbog, Denmark) magnetic flow meter for reference. Data were beamformed with an optimized transverse oscillation scheme for the TO VFI, and standard fourth-order estimators were employed for the velocity estimation. Directional RF lines were beamformed along the flow direction and cross-correlation employed to estimate the velocity magnitude. The velocities were determined for beam-to-flow angles of 60, 75 and 90 degrees. Using 32 emissions the standard deviation relative to the peak velocity for TO estimation was 7.0% at a beam-to-flow angle of 75° . This was 3.8% for directional beamforming and at 60° it was 2.2%. The general improvement, however, comes at an increase by a factor of roughly 11 in the number of calculations for the directional beamformation compared to the TO method.

  5. One pot direct synthesis of amides or oxazolines from carboxylic acids using Deoxo-Fluor reagent.

    Science.gov (United States)

    Kangani, Cyrous O; Kelley, David E

    2005-12-19

    A mild and highly efficient one pot-one step condensation and/or condensation-cyclization of various acids to amides and/or oxazolines using Deoxo-Fluor reagents is described. Parallel syntheses of various free fatty acids with 2-amino-2, 2-dimethyl-1-propanol resulted with excellent yields.

  6. Direct esterification of olive-pomace oil using mesoporous silica supported sulfonic acids

    Directory of Open Access Journals (Sweden)

    F. Alrouh

    2017-02-01

    Full Text Available Mesoporous silica MCM-41 and SBA-15 containing propyl sulfonic acid groups were synthesized according to the literature and were characterized by X-ray diffraction, N2 adsorption and the H+ exchange capacities of the sulfonic acid groups were titrated. The esterification reaction of glycerol with olive-pomace oil has been carried out by using prepared functionalized mesoporous silica (MCM-41 and SBA-15 as catalysts. It has been monitored by GC two fatty acids (palmitic and oleic acids as reactants in olive-pomace oil and their related monoacylglycerols (Glycerol monopalmitate GMP and monooleate GMO as reaction product. The catalytic activities of the functionalized mesoporous silica were compared with commercial catalysts, these included homogeneous catalysts (p-toluenesulfonic acid and heterogeneous catalysts (Amberlyst-15. The total yield of monoacylglycerols (GMO + GMP was nearly 40%. Remarkably, we found that MCM-41-SO3H was recycled at least 3 times without any loss of activity.

  7. Comparison of Rice Direct Seeding Methods (Mechanical and Manual with Transplanting Method

    Directory of Open Access Journals (Sweden)

    A Eyvani

    2014-04-01

    Full Text Available The main method of rice planting in Iran is transplanting. Due to poor mechanization of rice production, this method is laborious and costly. The other method is direct seeding in wet lands which is performed in the one third of rice cultivation area of the world. The most important problem in this method is high labor requirement of weed control. In order to compare the different rice planting methods (direct drilling, transplanting, and seed broadcasting a manually operated rice direct seeder (drum seeder was designed and fabricated. The research was conducted using a randomized complete block design with three treatments and three replications. Required draft force, field efficiency, effective field capacity, yield, and yield components were measured and the treatments were compared economically. Results showed that there were significant differences among the treatments from the view point of rice yield at the confidence level of 95% i.e. the transplanting method had the maximum yield. A higher rice yield was obtained from the direct seeder compared to the manual broadcasting method but, the difference between these two methods for crop yield was not significant even at the confidence level of the 95%. The coefficient of variation of seed distribution with direct seeding was more than 20%. The labor and time requirements per hectare reduced to 7 and 20 times, respectively when comparing the newly designed direct seeder with the transplanting method. The direct seeding method had the highest benefit to cost ratio in spite of its lower yield. Therefore, this method could be recommended in the rice growing regions.

  8. Biodegradation of azo dyes acid red 183, direct blue 15 and direct red 75 by the isolate Penicillium oxalicum SAR-3.

    Science.gov (United States)

    Saroj, Samta; Kumar, Karunesh; Pareek, Nidhi; Prasad, R; Singh, R P

    2014-07-01

    Soils contaminated with dyes were collected and screened for obtaining potential fungal strains for the degradation of azo dyes. A strain that demonstrated broad spectrum ability for catabolizing different azo dyes viz. Acid Red 183 (AR 183), Direct Blue 15 (DB 15) and Direct Red 75 (DR 75) at 100 mg L(-1) concentration was subsequently identified as Penicillium oxalicum SAR-3 based on 18S and internal transcribed spacer (ITS) rDNA gene sequence analysis. The strain has shown remarkably higher levels of degradation (95-100%) for almost all the dyes within 120 h at 30°C at pH 7.0. Notable levels of manganese peroxidase (659.4 ± 20 UL(-1)) during dye decolorization indicated the involvement of this enzyme in the decolorization process. The dyes following decolorization were catabolized as evident by spectroscopic analyses.

  9. Field Comparison of Direct-Push Approaches for Determination of K-Profiles

    Science.gov (United States)

    Dietrich, P.; Butler, J. J.; Yaramanci, U.; Wittig, V.; Tiggelmann, L.; Schoofs, S.

    2003-12-01

    A large body of theoretical and experimental research has shown that spatial variations in hydraulic conductivity (K) are a significant factor in determining how groundwater and accompanying contaminants move in the subsurface. Therefore, a wide variety of direct and indirect techniques have been developed for the characterization of K variations at a site. Methods based on direct-push technology have much potential for use in shallow unconsolidated settings. However, the various direct-push methods differ in their expense, in terms of time, money, and effort, and the nature (qualitative vs. quantitative) of the information that they can provide. A field study was carried out at a test site near Nauen, Germany to evaluate and compare several direct-push methods for determination of spatial variations in K. The test site was established by the Department of Applied Geophysics of the Technical University of Berlin in collaboration with the German Federal Institute for Geosciences and Natural Resources. Extensive geophysical surface measurements (surface nuclear magnetic resonance, georadar, refraction seismic, and 2D dc geoelectrics), as well as data from a continuously cored borehole, are available. These data provide a controlled framework for the evaluation of different direct-push methods for the characterization of spatial variations in hydraulic conductivity. The following direct-push methods were investigated in this study: electrical conductivity (EC) and cone penetrometer (CPT) logging, slug tests, injection logging, and the direct-push permeameter (DPP). In addition, natural gamma (NG) logging was performed in pipe installed with direct-push technology. EC, CPT, and NG logging are very fast, but do not provide direct estimates of K. Their successful use for site characterization depends on the appropriateness of the applied empirical relationships. As shown by the results from Nauen, EC, CPT, and NG logging are often limited to the delineation of major

  10. Radionuclide cystography in children: comparison of direct (retrograde) and indirect (intravenous) techniques

    Energy Technology Data Exchange (ETDEWEB)

    Majd, M.; Kass, E.J.; Belman, A.B. (Children' s Hospital National Medical Center, Washington, DC (U.S.A.))

    1985-01-01

    One hundred twenty children with a known history of vesico-ureteral reflux were evaluated by both direct and indirect methods of radionuclide cystography. The indirect studies were technically optimal in only 99 patients. In 20 of them neither the direct cystogram nor the indirect cystogram showed evidence of reflux. In the remaining 79 patients the direct cystograms demonstrated reflux in 112 ureters while the indirect cystograms showed reflux in only 66 ureters, a false negative rate of 41%. Reflux was not demonstrated in any on the indirect study which was not also noted on the direct cystogram. Indirect radionuclide cystography has a low sensitivity for the detection of reflux and should not be used as the initial screening test. If renal scintigraphy is part of the follow-up evaluation of patients with previously documented reflux, an indirect radionuclide cystogram may be obtained. However, the study is only reliable if reflux is noted. A negative study does not necessarily exclude reflux, and the patient should be evaluated further by direct cystography.

  11. Comparison between NuGEN's WT-Ovation Pico and one-direct amplification systems.

    Science.gov (United States)

    Morse, Alison M; Carballo, Valentina; Baldwin, Donald A; Taylor, Christopher G; McIntyre, Lauren M

    2010-09-01

    Differential gene expression between groups of homogenous cell types is a biological question whose time has come. RNA can be extracted from small numbers of cells, such as those isolated by laser-capture microdissection, but the small amounts obtained often require amplification to enable whole genome transcriptome profiling by technologies such as microarray analysis and RNA-seq. Recently, advances in amplification procedures make amplification directly from whole cell lysates possible. The aim of this study was to compare two amplification systems for variations in observed RNA abundance attributable to the amplification procedure for use with small quantities of cells isolated by laser-capture microdissection. Arabidopsis root cells undergoing giant cell formation as a result of nematode infestation and uninfested control root cells were laser-captured and used to evaluate two amplification systems. One, NuGEN's WT-Ovation Pico (Pico) amplification system, uses total RNA as starting material, and the other, NuGEN's WT-One-Direct (One-Direct) amplification system, uses lysate containing the captured cells. The reproducibility of whole genome transcript profiling and correlations of both systems were investigated after microarray analysis. The One-Direct system was less reproducible and more variable than the Pico system. The Pico amplification kit resulted in the detection of thousands of differentially expressed genes between giant cells and control cells. This is in marked contrast to the relatively few genes detected after amplification with the One-Direct amplification kit.

  12. Precision direct photon spectra at high energy and comparison to the 8 TeV ATLAS data

    CERN Document Server

    Schwartz, Matthew D

    2016-01-01

    The direct photon spectrum is computed to the highest currently available precision and compared to ATLAS data from 8 TeV collisions at the LHC. The prediction includes threshold resummation at next-to-next-to-next-to-leading logarithmic order through the program PeTeR, matched to next-to-leading fixed order with fragmentation effects using JetPhox and includes the resummation of leading-logarithmic electroweak Sudakov effects. Remarkably, improved agreement with data can be seen when each component of the calculation is added successively. This comparison demonstrates the importance of both threshold logs and electroweak Sudakov effects. Numerical values for the predictions are included.

  13. Design and Comparison of a Novel Stator Interior Permanent Magnet Generator for Direct-Drive Wind Turbines

    DEFF Research Database (Denmark)

    Zhang, Johan Xi; Chen, Zhe; Cheng, M.

    2007-01-01

    A novel stator interior permanent magnet generator (SIPMG) is presented. A modular stator design is used for convenience in manufacture and maintenance. The generator has the advantages of rugged rotor and concentrated winding design whereas the torque ripple is smaller than that produced...... by a doubly salient machine. Several low-speed multi-pole SIPMGs are designed for direct-drive wind turbines with ratings from 3 to 10 MW. Comparisons between the SIPMG and rotor-surface-mounted permanent magnet synchronous generator (PMSG) show that the SIPMGs have about 120% torque density and 78% cost per...

  14. Direct block of the cystic fibrosis transmembrane conductance regulator Cl(-) channel by niflumic acid.

    Science.gov (United States)

    Scott-Ward, T S; Li, H; Schmidt, A; Cai, Z; Sheppard, D N

    2004-01-01

    Niflumic acid is widely used to inhibit Ca(2+) -activated Cl(-) channels. However, the chemical structure of niflumic acid resembles that of diphenylamine-2-carboxylate, a drug that inhibits the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel. To investigate how niflumic acid inhibits CFTR Cl(-) channel, we studied recombinant wild-type human CFTR in excised inside-out membrane patches. When added to the intracellular solution, niflumic acid caused a concentration- and voltage-dependent decrease of CFTR Cl(-) current with half-maximal inhibitory concentration (K(i)) of 253 microM and Hill co-efficient of approximately 1, at -50 mV. Niflumic acid inhibition of single CFTR Cl(-) channels was characterized by a very fast, flickery block that decreased dramatically current amplitude without altering open-probability. Consistent with these data, spectral analysis of CFTR Cl(-) currents suggested that channel block by niflumic acid was described by the closed open blocked kinetic scheme with blocker on rate (k(on)) = 13.9 x 10(6) M(-1)s(-1), off rate (k(off))=3348 s(-1) and dissociation constant (K(d)) = 241 microM, at -50 mV. Based on these data, we tested the effects of niflumic acid on transepithelial Cl(-) secretion and cyst growth using type I MDCK epithelial cells. Niflumic acid (200 microM) inhibited cAMP-stimulated, bumetanide-sensitive short-circuit current by 55%. Moreover, the drug potently retarded cyst growth. We conclude that niflumic acid is an open-channel blocker of CFTR that inhibits Cl(-) permeation by plugging the channel pore. It or related agents might be of value in the development of new therapies for autosomal dominant polycystic kidney disease.

  15. Comparison of direct and indirect measurement of the elastocaloric effect in natural rubber

    Science.gov (United States)

    Xie, Zhongjian; Sebald, Gael; Guyomar, Daniel

    2016-01-01

    The directly measured temperature change Δ T upon deformation (elastocaloric effect) of natural rubber was compared with indirect method, which is deduced from the Clausius-Clapeyron factor ( ∂ σ / ∂ T ) ɛ , where σ is the stress and ɛ is the strain. The factor ( ∂ σ / ∂ T ) ɛ can be measured by two different methods. One is to measure the stress vs. strain behavior at different static temperatures. It is found that the Δ T deduction is underestimated or even of opposite sign compared with the directly measured one. These behaviors are different from elastocaloric effect of shape memory alloys. An interpretation based on strain-induced crystallite is proposed. The other characterization is to measure the stress vs. temperature at constant strain. It results in a prediction, which is in good quantitative agreement with the directly measured one. The stress appears then to be a non-state variable, thus questioning the ergodicity of the material.

  16. Comparison of the hydrolytic degradation and deformation properties of a PLLA-lauric acid based family of biomaterials.

    Science.gov (United States)

    Renouf-Glauser, Annette C; Rose, John; Farrar, David F; Cameron, Ruth Elizabeth

    2006-02-01

    Addition of lauric acid to PLLA results in a significantly increased rate of hydrolytic degradation, with the time-to-loss of tensile strength directly related to the concentration of lauric acid. In this study, the hydrolytic degradation profiles of four materials were studied: amorphous PLLA, amorphous PLLA containing 1.8 wt % lauric acid, amorphous PLLA containing 4.5 wt % lauric acid, and pre-crystallized PLLA containing 1.8 wt % lauric acid. Hydrolytic degradation was monitored through mass profiles, molecular weight profiles, crystallinity and the development of mechanical properties and deformation mechanisms (through simultaneous small-angle X-ray scattering and tensile testing), and a "phase diagram" of properties suggested. The key factor in determining the development of properties was found to be the time at which crystallization occurred in relation to the loss of molecular weight, with the two factors most affecting this being the lauric acid content and the pre-degradation annealing treatment.

  17. A Direct Comparison of Two Densely Sampled HIV Epidemics: The UK and Switzerland

    Science.gov (United States)

    Ragonnet-Cronin, Manon L.; Shilaih, Mohaned; Günthard, Huldrych F.; Hodcroft, Emma B.; Böni, Jürg; Fearnhill, Esther; Dunn, David; Yerly, Sabine; Klimkait, Thomas; Aubert, Vincent; Yang, Wan-Lin; Brown, Alison E.; Lycett, Samantha J.; Kouyos, Roger; Brown, Andrew J. Leigh

    2016-09-01

    Phylogenetic clustering approaches can elucidate HIV transmission dynamics. Comparisons across countries are essential for evaluating public health policies. Here, we used a standardised approach to compare the UK HIV Drug Resistance Database and the Swiss HIV Cohort Study while maintaining data-protection requirements. Clusters were identified in subtype A1, B and C pol phylogenies. We generated degree distributions for each risk group and compared distributions between countries using Kolmogorov-Smirnov (KS) tests, Degree Distribution Quantification and Comparison (DDQC) and bootstrapping. We used logistic regression to predict cluster membership based on country, sampling date, risk group, ethnicity and sex. We analysed >8,000 Swiss and >30,000 UK subtype B sequences. At 4.5% genetic distance, the UK was more clustered and MSM and heterosexual degree distributions differed significantly by the KS test. The KS test is sensitive to variation in network scale, and jackknifing the UK MSM dataset to the size of the Swiss dataset removed the difference. Only heterosexuals varied based on the DDQC, due to UK male heterosexuals who clustered exclusively with MSM. Their removal eliminated this difference. In conclusion, the UK and Swiss HIV epidemics have similar underlying dynamics and observed differences in clustering are mainly due to different population sizes.

  18. A Direct Comparison of Two Densely Sampled HIV Epidemics: The UK and Switzerland.

    Science.gov (United States)

    Ragonnet-Cronin, Manon L; Shilaih, Mohaned; Günthard, Huldrych F; Hodcroft, Emma B; Böni, Jürg; Fearnhill, Esther; Dunn, David; Yerly, Sabine; Klimkait, Thomas; Aubert, Vincent; Yang, Wan-Lin; Brown, Alison E; Lycett, Samantha J; Kouyos, Roger; Brown, Andrew J Leigh

    2016-09-19

    Phylogenetic clustering approaches can elucidate HIV transmission dynamics. Comparisons across countries are essential for evaluating public health policies. Here, we used a standardised approach to compare the UK HIV Drug Resistance Database and the Swiss HIV Cohort Study while maintaining data-protection requirements. Clusters were identified in subtype A1, B and C pol phylogenies. We generated degree distributions for each risk group and compared distributions between countries using Kolmogorov-Smirnov (KS) tests, Degree Distribution Quantification and Comparison (DDQC) and bootstrapping. We used logistic regression to predict cluster membership based on country, sampling date, risk group, ethnicity and sex. We analysed >8,000 Swiss and >30,000 UK subtype B sequences. At 4.5% genetic distance, the UK was more clustered and MSM and heterosexual degree distributions differed significantly by the KS test. The KS test is sensitive to variation in network scale, and jackknifing the UK MSM dataset to the size of the Swiss dataset removed the difference. Only heterosexuals varied based on the DDQC, due to UK male heterosexuals who clustered exclusively with MSM. Their removal eliminated this difference. In conclusion, the UK and Swiss HIV epidemics have similar underlying dynamics and observed differences in clustering are mainly due to different population sizes.

  19. Mercaptoacetate blocks fatty acid-induced GLP-1 secretion in male rats by directly antagonizing GPR40 fatty acid receptors.

    Science.gov (United States)

    Li, Ai-Jun; Wang, Qing; Dinh, Thu T; Simasko, Steve M; Ritter, Sue

    2016-04-15

    Mercaptoacetate (MA) is an orexigenic agent reported to block fatty acid (FA) oxidation. Recently, however, we reported evidence from isolated nodose ganglion neurons that MA antagonizes the G protein-coupled long- and medium-chain FA receptor GPR40. GPR40 mediates FA-induced secretion of the satietogenic incretin peptide glucagon-like peptide 1 (GLP-1), by enteroendocrine L cells, as well as FA-induced enhancement of glucose-stimulated insulin secretion. Our results in cultured nodose neurons suggest that MA would also block GPR40 in enteroendocrine cells controlling GLP-1 secretion. If so, this would suggest an alternative mechanism by which MA increases food intake. We tested the hypothesis that MA blocks FA-induced GLP-1 secretion in vitro using cultured STC-1 cells (a murine enteroendocrine cell line) and in vivo in adult male rats. In vitro, MA blocked the increase in both cytosolic Ca(2+)and GLP-1 release stimulated by FAs and also reduced (but less effectively) the response of STC-1 cells to grifolic acid, a partial agonist of the GPR120 FA receptor. In vivo, MA reduced GLP-1 secretion following olive oil gavage while also increasing glucose and decreasing insulin levels. The carnitine palmatoyltransferase 1 antagonist etomoxir did not alter these responses. Results indicate that MA's actions, including its orexigenic effect, are mediated by GPR40 (and possibly GPR120) receptor antagonism and not by blockade of fat oxidation, as previously believed. Analysis of MA's interaction with GPR40 may facilitate understanding of the multiple functions of this receptor and the manner in which FAs participate in the control of hunger and satiety.

  20. A comparison of acid rock drainage treatment scenarios at the former Britannia Mine

    Energy Technology Data Exchange (ETDEWEB)

    O' Hearn, T. [British Columbia Research Inc., Vancouver, BC (Canada); Klein, B. [British Columbia Univ., Vancouver, BC (Canada)

    2000-07-01

    Pilot scale tests of three acid rock draining (ARD) treatment processes were conducted on the Anaconda Britannia Mine effluent for comparative evaluation. The three processes tested included: (1) the high density sludge (HDS) process, (2) a modified version of the HDS that uses pulp mill ash wastes instead of lime, and (3) the Bio-sulfide process. The technical aspects relating to effluent quality and sludge disposal were assessed for each process. A comparison was also made on capital and operating costs. It was concluded that all three process showed promise as a potential remediation treatment for Britannia ARD. HDS and modified HDS treatments yielded effluent specifications that are within the federal discharge limits. In this test, the Bio-sulfide process produced effluents which meet federal criteria for metals concentration, but failed to raise pH levels enough. HDS and Bio-sulfide/HDS treatment scenarios were the most effective of the three alternatives examined. Despite the high risk associated with new technologies, it was recommended that new technologies should be considered as potential remediation methods for mine effluent. HDS was considered to be the most suitable process option to treat the Britannia effluent. 6 refs., 9 tabs.

  1. Retrieval comparison of EndNote to search MEDLINE (Ovid and PubMed) versus searching them directly.

    Science.gov (United States)

    Gall, Carole; Brahmi, Frances A

    2004-01-01

    Using EndNote version 7.0, the authors tested the search capabilities of the EndNote search engine for retrieving citations from MEDLINE for importation into EndNote, a citation management software package. Ovid MEDLINE and PubMed were selected for the comparison. Several searches were performed on Ovid MEDLINE and PubMed using EndNote as the search engine, and the same searches were run on both Ovid and PubMed directly. Findings indicate that it is preferable to search MEDLINE directly rather than using EndNote. The publishers of EndNote do warn its users about the limitations of their product as a search engine when searching external databases. In this article, the limitations of EndNote as a search engine for searching MEDLINE were explored as related to MeSH, non-MeSH, citation verification, and author searching.

  2. Measurements of ionospheric TEC in the direction of GPS satellites and comparison with three ionospheric models

    Directory of Open Access Journals (Sweden)

    E. Zuccheretti

    1997-06-01

    Full Text Available The IEN Galileo Ferraris uses GPS for time and frequency synchronization. To obtain high performance it is important to reduce the error due to the ionospheric time-delay in GPS measurements. Evaluations of TEC in the direction of GPS satellites, obtained from three different ionospheric models, have been compared with corresponding measurements by GPS signal.

  3. Data-parallel tomographic reconstruction : A comparison of filtered backprojection and direct Fourier reconstruction

    NARCIS (Netherlands)

    Roerdink, Jos B.T.M.; Westenberg, Michel A.

    1998-01-01

    We consider the parallelization of two standard 2D reconstruction algorithms, filtered backprojection and direct Fourier reconstruction, using the data-parallel programming style. The algorithms are implemented on a Connection Machine CM-5 with 16 processors and a peak performance of 2 Gflop/s. (C)

  4. A comparison of directional atherectomy with coronary angioplasty in patients with coronary artery disease

    NARCIS (Netherlands)

    E.J. Topol (Eric); F. Leya; C.A. Pinkerton; P.L. Whitlow (Patrick); B. Hofling; C.A. Simonton; R.R. Masden; P.W.J.C. Serruys (Patrick); M.B. Leon (Martin); D.O. Williams (David); S.B. King 3rd (Spencer); B. Daniel; D.B. Mark (Daniel); J.M. Isner; D.R. Holmes Jr (David); S.G. Ellis (Stephen); K.L. Lee (Kerry); G.P. Keeler; L.G. Berdan (Lisa); T. Hinohara; R.M. Califf (Robert)

    1993-01-01

    textabstractBACKGROUND. Directional coronary atherectomy is a new technique of coronary revascularization by which atherosclerotic plaque is excised and retrieved from target lesions. With respect to the rate of restenosis and clinical outcomes, it is not known how this procedure compares with ballo

  5. Comparison of input devices in an ISEE direct timbre manipulation task

    NARCIS (Netherlands)

    Vertegaal, Roel; Eaglestone, Barry

    1996-01-01

    The representation and manipulation of sound within multimedia systems is an important and currently under-researched area. The paper gives an overview of the authors' work on the direct manipulation of audio information, and describes a solution based upon the navigation of four-dimensional scaled

  6. A Comparison of Activity-Based Intervention and Embedded Direct Instruction When Teaching Emergent Literacy Skills

    Science.gov (United States)

    Botts, Dawn C.; Losardo, Angela S.; Tillery, Christina Y.; Werts, Margaret G.

    2014-01-01

    This replication study focused on the effectiveness of two different intervention approaches, activity-based intervention and embedded direct instruction, on the acquisition, generalization, and maintenance of phonological awareness, a key area of emergent literacy, by preschool children with language delays. Five male preschool participants with…

  7. Are Horses Like Zebras, or Vice Versa? Children's Sensitivity to the Asymmetries of Directional Comparisons

    Science.gov (United States)

    Chestnut, Eleanor K.; Markman, Ellen M.

    2016-01-01

    Adults exhibit strong preferences when framing symmetrical relations. Adults prefer, for example, "A zebra is like a horse" to "A horse is like a zebra," and "The bicycle is near the building" to "The building is near the bicycle." This is because directional syntax requires more typical or prominent items…

  8. A Comparison of Pyramidal Staff Training and Direct Staff Training in Community-Based Day Programs

    Science.gov (United States)

    Haberlin, Alayna T.; Beauchamp, Ken; Agnew, Judy; O'Brien, Floyd

    2012-01-01

    This study evaluated two methods of training staff who were working with individuals with developmental disabilities: pyramidal training and consultant-led training. In the pyramidal training, supervisors were trained in the principles of applied behavior analysis (ABA) and in delivering feedback. The supervisors then trained their direct-care…

  9. Optimization and Comparison of Direct and Indirect Supercritical Carbon Dioxide Power Plant Cycles for Nuclear Applications

    Energy Technology Data Exchange (ETDEWEB)

    Edwin A. Harvego; Michael G. McKellar

    2011-11-01

    There have been a number of studies involving the use of gases operating in the supercritical mode for power production and process heat applications. Supercritical carbon dioxide (CO2) is particularly attractive because it is capable of achieving relatively high power conversion cycle efficiencies in the temperature range between 550 C and 750 C. Therefore, it has the potential for use with any type of high-temperature nuclear reactor concept, assuming reactor core outlet temperatures of at least 550 C. The particular power cycle investigated in this paper is a supercritical CO2 Recompression Brayton Cycle. The CO2 Recompression Brayton Cycle can be used as either a direct or indirect power conversion cycle, depending on the reactor type and reactor outlet temperature. The advantage of this cycle when compared to the helium Brayton cycle is the lower required operating temperature; 550 C versus 850 C. However, the supercritical CO2 Recompression Brayton Cycle requires an operating pressure in the range of 20 MPa, which is considerably higher than the required helium Brayton cycle operating pressure of 8 MPa. This paper presents results of analyses performed using the UniSim process analyses software to evaluate the performance of both a direct and indirect supercritical CO2 Brayton Recompression cycle for different reactor outlet temperatures. The direct supercritical CO2 cycle transferred heat directly from a 600 MWt reactor to the supercritical CO2 working fluid supplied to the turbine generator at approximately 20 MPa. The indirect supercritical CO2 cycle assumed a helium-cooled Very High Temperature Reactor (VHTR), operating at a primary system pressure of approximately 7.0 MPa, delivered heat through an intermediate heat exchanger to the secondary indirect supercritical CO2 Brayton Recompression cycle, again operating at a pressure of about 20 MPa. For both the direct and indirect cycles, sensitivity calculations were performed for reactor outlet temperature

  10. Gamma-aminobutyric acid and GABA_A receptors are involved in directional selectivity of pretectal neurons in pigeons

    Institute of Scientific and Technical Information of China (English)

    肖泉; 付煜西; 胡婧; 高洪峰; 王书荣

    2000-01-01

    The present study describes the effects of gamma-aminobutyric acid (GABA) and its antagonists, bicuculline and 2-hydroxysaclofen, on visual responses of neurons in the pigeon nucleus lentiformis mesencephali (nLM). The results indicate that GABA significantly reduces both spontaneous activity and visual responsiveness, and GABAA antagonist bicuculline but not GABAB antagonist 2-hydroxysaclofen enhances visual responses of nLM cells examined. Furthermore, inhibition produced by motion in the null-direction of pretectal neurons is diminished by bicuculline but not by 2-hydroxysaclofen. It is therefore concluded that the null-direction inhibition of directional cells in the pigeon nLM is predominantly mediated by GABA and GABAA receptors. This inhibition may at least in part underlie directional asymmetry of optokinetic responses.

  11. Comparison of the marginal adaptation of direct and indirect composite inlay restorations with optical coherence tomography

    Science.gov (United States)

    TÜRK, Ayşe Gözde; SABUNCU, Metin; ÜNAL, Sena; ÖNAL, Banu; ULUSOY, Mübin

    2016-01-01

    ABSTRACT Objective The purpose of the study was to use the photonic imaging modality of optical coherence tomography (OCT) to compare the marginal adaptation of composite inlays fabricated by direct and indirect techniques. Material and Methods Class II cavities were prepared on 34 extracted human molar teeth. The cavities were randomly divided into two groups according to the inlay fabrication technique. The first group was directly restored on cavities with a composite (Esthet X HD, Dentsply, Germany) after isolating. The second group was indirectly restored with the same composite material. Marginal adaptations were scanned before cementation with an invisible infrared light beam of OCT (Thorlabs), allowing measurement in 200 µm intervals. Restorations were cemented with a self-adhesive cement resin (SmartCem2, Dentsply), and then marginal adaptations were again measured with OCT. Mean values were statistically compared by using independent-samples t-test and paired samples t-test (prestorations after cementation (p=0.00008839, p=0.000000952 for direct and indirect inlays, respectively). The mean marginal discrepancy value of the direct group increased from 56.88±20.04 µm to 91.88±31.7 µm, whereas the indirect group increased from 107.54±35.63 µm to 170.29±54.83 µm. Different techniques are available to detect marginal adaptation of restorations, but the OCT system can give quantitative information about resin cement thickness and its interaction between tooth and restoration in a nondestructive manner. Conclusions Direct inlays presented smaller marginal discrepancy than indirect inlays. The marginal discrepancy values were increased for all restorations that refer to cement thickness after cementation. PMID:27556210

  12. Comparison of EUB directive 038-2007 to other energy-industry noise standards

    Energy Technology Data Exchange (ETDEWEB)

    Wong, G.; Wang, L. [ATCO Noise Management, Calgary, AB (Canada)

    2007-07-01

    The Alberta Energy and Utilities Board (EUB) regulates the development of Alberta's energy resources. Noise Control Directive 038 is largely directed at the extensive oil and gas production and transportation industry in the province. In February 2007, the EUB issued a revised version of Directive 038 to incorporate several new requirements and update others. Among them, low-frequency noise was considered along with stricter requirements on noise modeling and measurement. The Directive is very comprehensive, covering procedures on performing surveys, applicable monitoring conditions and investigating complaints. This paper compared Directive 038 to similar regulations and guidelines in other jurisdictions in order to assess their trends and development in the industry. It compared noise limit criteria such as permissible sound levels, meteorological conditions, prediction modeling parameters and assumptions, measurement protocols and reporting requirements. The oil and gas or energy industry noise standards that were compared in this paper included: the Colorado Oil and Gas Conservation Commission's noise control regulations; the United States' Federal Energy Regulatory Commission's report on air and noise quality; the World Bank Group pollution prevention and abatement handbook on onshore oil and gas development; the State of Michigan's oil and gas noise regulations; New Mexico's City of Farmington regulations for oil and gas wells; and the sound level limits for oil and gas production in the City of Ripon, California. It was noted that in most jurisdictions, the criteria do not include limits on low-frequency noise unless specific complaints have been made. Many regulations also give simplified criteria outlining A-weighted level limits at set distances from the source. It was concluded that the EUB's comprehensive set of criteria gives the energy industry a more useful tool to proactively include noise mitigation in their

  13. Estimating Steatosis Prevalence in Overweight and Obese Children: Comparison of Bayesian Small Area and Direct Methods

    Directory of Open Access Journals (Sweden)

    Hamid Reza Khalkhali

    2016-09-01

    Full Text Available Background Often, there is no access to sufficient sample size to estimate the prevalence using the method of direct estimator in all areas. The aim of this study was to compare small area’s Bayesian method and direct method in estimating the prevalence of steatosis in obese and overweight children. Materials and Methods: In this cross-sectional study, was conducted on 150 overweight and obese children aged 2 to 15 years referred to the Children's digestive clinic of Urmia University of Medical Sciences- Iran, in 2013. After Body mass index (BMI calculation, children with overweight and obese were assessed in terms of primary tests of obesity screening. Then children with steatosis confirmed by abdominal Ultrasonography, were referred to the laboratory for doing further tests. Steatosis prevalence was estimated by direct and Bayesian method and their efficiency were evaluated using mean-square error Jackknife method. The study data was analyzed using the open BUGS3.1.2 and R2.15.2 software. Results: The findings indicated that estimation of steatosis prevalence in children using Bayesian and direct methods were between 0.3098 to 0.493, and 0.355 to 0.560 respectively, in Health Districts; 0.3098 to 0.502, and 0.355 to 0.550 in Education Districts; 0.321 to 0.582, and 0.357 to 0.615 in age groups; 0.313 to 0.429, and 0.383 to 0.536 in sex groups. In general, according to the results, mean-square error of Bayesian estimation was smaller than direct estimation (P

  14. Aerosol microphysical retrievals from precision filter radiometer direct solar radiation measurements and comparison with AERONET

    Science.gov (United States)

    Kazadzis, S.; Veselovskii, I.; Amiridis, V.; Gröbner, J.; Suvorina, A.; Nyeki, S.; Gerasopoulos, E.; Kouremeti, N.; Taylor, M.; Tsekeri, A.; Wehrli, C.

    2014-07-01

    Synchronized sun-photometric measurements from the AERONET-CIMEL (AErosol RObotic NETwork) and GAW-PFR (Global Atmospheric Watch-Precision Filter Radiometer) aerosol networks are used to compare retrievals of the aerosol optical depth (AOD), effective radius, and volume concentration during a high-temporal-resolution measurement campaign at the Athens site in the Mediterranean Basin from 14 to 22 July 2009. During this period, direct-sun AOD retrievals from both instruments exhibited small differences in the range 0.01-0.02. The AODs measured with CIMEL and PFR instruments were inverted to retrieve particle microphysical properties using the linear estimation (LE) technique. For low aerosol loads (AOD CIMEL values for both direct-sun data and inversion data. At higher loads (AOD > 0.4), measurements of the effective radius by the PFR are consistently 20 % lower than CIMEL for both direct-sun and inversion data. Volume concentrations at low aerosol loads from the PFR are up to 80% higher than the CIMEL for direct-sun data but are up to 20% lower when derived from inversion data under these same conditions. At higher loads, the percentage difference in volume concentrations from the PFR and CIMEL is systematically negative, with inversion data predicting differences 30% lower than those obtained from direct-sun data. An assessment of the effect of errors in the AOD retrieval on the estimation of PFR bulk parameters was performed and demonstrates that it is possible to estimate the particle volume concentration and effective radius with an uncertainty < 65% when AOD < 0.2 and when input errors are as high as 10%.

  15. RP-HPLC Determination and Pharmacokinetic Comparison of Cinnamic Acid in Rat Plasma After Administration of Di-Gu-Pi Decoction and Pure Cinnamic Acid

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A sensitive, simple, and accurate method was developed for the determination and pharmacokinetic comparison of cinnamic acid in rat plasma after the administration of a Traditional Chinese Medicinal preparation, Di-Gu-Pi decoction, and pure cinnamic acid using RP-HPLC. Di-Gu-Pi was extracted with 5% aqueous sodium bicarbonate, which was followed by purification with ion exchange column chromatography. The plasma samples taken from rats were deproteinized with methanol. The reversed-phase(HPLC) system with a Diamonsil C18 column and methanol-acetonitrile-water (8∶32∶60, volume ratio) (adjusted to pH=3.0 with glacial acetic acid) as the mobile phase was employed for the separation of cinnamic acid in the plasma samples. The detection was set at 272 nm and 3-(p-fluorophenyl)-2-propenoic acid was chosen as the internal standard. The calibration curve was linear in a range from 0.10 to 25.0 μg/mL (R2=0.9988, n=9). The precision was 3.42%-10.10%; the between-day precision was 2.84%-8.91%; the accuracy was -1.51%-1.26%; the mean recovery was 99.9%. The method was found to be sensitive, simple, accurate and appropriate for the determination of cinnamic acid.

  16. [Comparison of direct microscopy, culture and polymerase chain reaction methods for the diagnosis of cutaneous leishmaniasis].

    Science.gov (United States)

    Ertabaklar, Hatice; Özlem Çalışkan, Serçin; Boduç, Erengül; Ertuğ, Sema

    2015-01-01

    Cutaneous leishmaniasis (CL) is an endemic disease especially in Southeastern Anatolia of Turkey and recently shows a trend for spread to other regions of the country including the Aegean region. The diagnosis of CL is based on combined evaluation of epidemiological data with the clinical symptoms and laboratory findings. Direct microscopic examination and culture methods are mainly used in the routine diagnosis of CL, while molecular methods are mainly used for research. The aim of this study was to detect the presence of Leishmania spp. in samples obtained from CL-suspected patients by using direct microscopy, culture and polymerase chain reaction (PCR) methods and to compare the results. A total of 55 patients who were admitted to Parasitology Laboratory of Adnan Menderes University Hospital, Aydin (located at Aegean region in Turkey), between 2012-2014 were included in the study. Smear preparations from the skin lesions of cases were fixed and stained with Giemsa, and the presence of amastigote forms were evaluated by direct microscopy. NNN medium was used for the cultivation of samples. Total genomic DNA of Leishmania from the samples were extracted with a commercial kit (NucleoSpin Tissue(®) Kit, Macherey-Nagel, Germany) and PCR was performed by using 13A and 13B primers to amplify the 116 base pair fragment of Leishmania spp. specific kinetoplast DNA. Amastigotes were observed in 29 (53%) of the 55 samples by direct microscopy, promastigotes were detected among 34 (62%) samples in culture, and parasite-specific amplicons were revealed in 30 (55%) samples by PCR. All assays were positive in 24 patients while in 18 patients all of the tests yielded negative results. Thirty-seven (67%) out of 55 cases were diagnosed as CL when reactivity in at least one of these three methods were considered as positive. Accordingly the positivity rates of the methods were 78.4% (29/37) for direct microscopy, 92% (34/37) for culture and 81.1% (30/37) for PCR in CL

  17. Direct protein-protein interactions and substrate channeling between cellular retinoic acid binding proteins and CYP26B1.

    Science.gov (United States)

    Nelson, Cara H; Peng, Chi-Chi; Lutz, Justin D; Yeung, Catherine K; Zelter, Alex; Isoherranen, Nina

    2016-08-01

    Cellular retinoic acid binding proteins (CRABPs) bind all-trans-retinoic acid (atRA) tightly. This study aimed to determine whether atRA is channeled directly to cytochrome P450 (CYP) CYP26B1 by CRABPs, and whether CRABPs interact directly with CYP26B1. atRA bound to CRABPs (holo-CRABP) was efficiently metabolized by CYP26B1. Isotope dilution experiments showed that delivery of atRA to CYP26B1 in solution was similar with or without CRABP. Holo-CRABPs had higher affinity for CYP26B1 than free atRA, but both apo-CRABPs inhibited the formation of 4-OH-RA by CYP26B1. Similar protein-protein interactions between soluble binding proteins and CYPs may be important for other lipophilic CYP substrates.

  18. An improved direct colorimetric method for the quantitative analysis of urinary hippuric acid as an index of toluene exposure

    Directory of Open Access Journals (Sweden)

    Ogata,Masana

    1977-08-01

    Full Text Available An improved direct colorimetric method for determining the concentration of urinary hippuric acid as an index of toluene exposure was described. One tenth ml of urine was diluted with 0.4 ml 0.01 M phosphate buffer H 6.9 and mixed with 0.5 ml pyridine. The mixture was layered on 0.2 ml benzenesulfonyl chloride. The reaction was started by mixing for one min with a mechanical shaker. The colored solution was allowed to stand for 30 min, diluted with 5 ml ethanol, and absorbance measured at 410 nm within 30 min after the dilution. The coefficient of variation of this method was 6% and the recovery 103% when urine contains about 0.2-0.5 mg hippuric acid per ml of urine. The concentration was linear up to 2.0 mg per ml hippuric acid in a specimen.

  19. Direct Spectroscopic Determination of Europium(Ⅱ) Concentration During Europium(Ⅲ) Electro-Reduction in Hydrochloric Acid Medium

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    UV-Vis spectroscopy was used to directly determine the concentration of Eu(Ⅱ) during electroreduction of Eu(Ⅲ) in hydrochloric acid medium. Electroreduction was carried out in a flow type electrolyzer with glassy carbon cathode at the constant potential of -800 mV vs. Ag/AgCl. The effects of oxygen and concentration of hydrochloric acid on the system were investigated. For 0.01 mol·L-1 hydrochloric acid, calibration curves for Eu(Ⅱ) absorption bands at 248 and 320 nm were constructed. Molar absorption coefficients were estimated to be 2016 and 648 L·mol-1·cm-1, respectively. The absorbance strongly decreased with decrease in pH of the solution, whereas concentration of chloride had only a negligible effect.

  20. Isolation of human minisatellite loci detected by synthetic tandem repeat probes: direct comparison with cloned DNA fingerprinting probes.

    Science.gov (United States)

    Armour, J A; Vergnaud, G; Crosier, M; Jeffreys, A J

    1992-08-01

    As a direct comparison with cloned 'DNA fingerprinting' probes, we present the results of screening an ordered array Charomid library for hypervariable human loci using synthetic tandem repeat (STR) probes. By recording the coordinates of positive hybridization signals, the subset of clones within the library detected by each STR probe can be defined, and directly compared with the set of clones detected by naturally occurring (cloned) DNA fingerprinting probes. The STR probes vary in the efficiency of detection of polymorphic minisatellite loci; among the more efficient probes, there is a strong overlap with the sets of clones detected by the DNA fingerprinting probes. Four new polymorphic loci were detected by one or more of the STR probes but not by any of the naturally occurring repeats. Sequence comparisons with the probe(s) used to detect the locus suggest that a relatively poor match, for example 10 out of 14 bases in a limited region of each repeat, is sufficient for the positive detection of tandem repeats in a clone in this type of library screening by hybridization. These results not only provide a detailed evaluation of the usefulness of STR probes in the isolation of highly variable loci, but also suggest strategies for the use of these multi-locus probes in screening libraries for clones from hypervariable loci.

  1. The Comparison of Hydrochloric Acid and Phosphoric Acid Treatments in the Preparation of Montmorillonite Catalysts for RNA Synthesis

    Science.gov (United States)

    Aldersley, Michael Frank; Joshi, Prakash C.; Huang, Yixing

    2017-02-01

    The treatment of clay minerals with a preliminary acid wash and titration to pH 7 has proven to generate catalysts for the most interesting of oligomerization reactions in which activated RNA-nucleotides generate oligomers up to 40-mers. Significantly, not all clay minerals become catalytic following this treatment and none are catalytic in the absence of such treatment. The washing procedure has been modified and explored further using phosphoric acid and the outcomes are compared to those obtained when clay samples are prepared following a hydrochloric acid wash.

  2. Comparison of Vector Velocity Imaging using Directional Beamforming and Transverse Oscillation for a Convex Array Transducer

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    2014-01-01

    rig with a stationary, laminar flow, and the volume flow was measured by a MAG 3000 (Danfos, Sønderbog, Denmark) magnetic flow meter for reference. Data were beamformed with an optimized transverse oscillation scheme for the TO VFI, and standard fourth-order estimators were employed for the velocity......Vector velocity imaging can reveal both the magnitude and direction of the blood velocity. Several techniques have been suggested for estimating the velocity, and this paper compares the performance for directional beamforming and transverse oscillation (TO) vector flow imaging (VFI). Data have...... been acquired using the SARUS experimental ultrasound scanner connected to a BK 8820e (BK Medical, Herlev, Denmark) convex array probe with 192 active elements. A duplex sequence with 129 B-mode emissions interleaved with 129 flow emissions has been made. The flow was generated in a recirculating flow...

  3. Comparison of direct and indirect pyrolysis of micro-algae Isochrysis.

    Science.gov (United States)

    Wang, Xin; Zhao, Bingwei; Tang, Xiaohan; Yang, Xiaoyi

    2015-03-01

    Yield and composition of pyrolysis oil in direct and indirect pyrolysis process were investigated which indicated that pyrolysis of defatted microalgae provided a potential way to convert protein and carbohydrate to biofuels. Defatted microalgae pyrolysis with lipid extraction has higher total oil yield than only microalgae direct pyrolysis. There was an increase for N-heterocyclic compounds and phenols and a decrease for hydrocarbons in defatted microalgae pyrolysis oil. There is an apparent decrease from C12 to C16 and nearly no carbon distribution from C17 to C22 for defatted microalgae pyrolysis. Based on composition of pyrolysis feedstock, pyrolysis oil yields were simulated by Compounds Biofuel Model and their accuracy was less than ±4.4%. Considering total oil yield and characteristics, microalgae pyrolysis after lipid extraction process is a promising way for microalgae utilization.

  4. Feedback in formative OSCEs: comparison between direct observation and video-based formats

    Directory of Open Access Journals (Sweden)

    Noëlle Junod Perron

    2016-11-01

    Full Text Available Introduction: Medical students at the Faculty of Medicine, University of Geneva, Switzerland, have the opportunity to practice clinical skills with simulated patients during formative sessions in preparation for clerkships. These sessions are given in two formats: 1 direct observation of an encounter followed by verbal feedback (direct feedback and 2 subsequent review of the videotaped encounter by both student and supervisor (video-based feedback. The aim of the study was to evaluate whether content and process of feedback differed between both formats. Methods: In 2013, all second- and third-year medical students and clinical supervisors involved in formative sessions were asked to take part in the study. A sample of audiotaped feedback sessions involving supervisors who gave feedback in both formats were analyzed (content and process of the feedback using a 21-item feedback scale. Results: Forty-eight audiotaped feedback sessions involving 12 supervisors were analyzed (2 direct and 2 video-based sessions per supervisor. When adjusted for the length of feedback, there were significant differences in terms of content and process between both formats; the number of communication skills and clinical reasoning items addressed were higher in the video-based format (11.29 vs. 7.71, p=0.002 and 3.71 vs. 2.04, p=0.010, respectively. Supervisors engaged students more actively during the video-based sessions than during direct feedback sessions (self-assessment: 4.00 vs. 3.17, p=0.007; active problem-solving: 3.92 vs. 3.42, p=0.009. Students made similar observations and tended to consider that the video feedback was more useful for improving some clinical skills. Conclusion: Video-based feedback facilitates discussion of clinical reasoning, communication, and professionalism issues while at the same time actively engaging students. Different time and conceptual frameworks may explain observed differences. The choice of feedback format should depend on

  5. Research on measurement of total luminous flux of single LED in direct comparison method

    Science.gov (United States)

    Huang, Biyong; Lai, Lei; Yin, Dejin; Cheng, Weihai; Lin, Fangsheng

    2016-09-01

    This paper focuses on traceability work on total luminous flux of single LED based on the direct camparison method applied for quantity transfer of incandescent lamps. During the test different color groups of LEDs have been chosen as standard to measure total luminous flux of sample LEDs. The test is accomplished in the current integrating sphere measurement system under specific conditions according to LED characteristics. As results obtained from the experiment, the uncertainties are also evaluated.

  6. Feedback in formative OSCEs: comparison between direct observation and video-based formats

    Science.gov (United States)

    Junod Perron, Noëlle; Louis-Simonet, Martine; Cerutti, Bernard; Pfarrwaller, Eva; Sommer, Johanna; Nendaz, Mathieu

    2016-01-01

    Introduction Medical students at the Faculty of Medicine, University of Geneva, Switzerland, have the opportunity to practice clinical skills with simulated patients during formative sessions in preparation for clerkships. These sessions are given in two formats: 1) direct observation of an encounter followed by verbal feedback (direct feedback) and 2) subsequent review of the videotaped encounter by both student and supervisor (video-based feedback). The aim of the study was to evaluate whether content and process of feedback differed between both formats. Methods In 2013, all second- and third-year medical students and clinical supervisors involved in formative sessions were asked to take part in the study. A sample of audiotaped feedback sessions involving supervisors who gave feedback in both formats were analyzed (content and process of the feedback) using a 21-item feedback scale. Results Forty-eight audiotaped feedback sessions involving 12 supervisors were analyzed (2 direct and 2 video-based sessions per supervisor). When adjusted for the length of feedback, there were significant differences in terms of content and process between both formats; the number of communication skills and clinical reasoning items addressed were higher in the video-based format (11.29 vs. 7.71, p=0.002 and 3.71 vs. 2.04, p=0.010, respectively). Supervisors engaged students more actively during the video-based sessions than during direct feedback sessions (self-assessment: 4.00 vs. 3.17, p=0.007; active problem-solving: 3.92 vs. 3.42, p=0.009). Students made similar observations and tended to consider that the video feedback was more useful for improving some clinical skills. Conclusion Video-based feedback facilitates discussion of clinical reasoning, communication, and professionalism issues while at the same time actively engaging students. Different time and conceptual frameworks may explain observed differences. The choice of feedback format should depend on the educational

  7. Comparison of Single and Multiple Flow Direction Algorithms for Computing Topographic Parameters in TOPMODEL

    Science.gov (United States)

    Wolock, David M.; McCabe, Gregory J.

    1995-05-01

    Single flow direction (sfd) and multiple flow direction (mfd) algorithms were used to compute the spatial and statistical distributions of the topographic index used in the watershed model TOPMODEL. An sfd algorithm assumes that subsurface flow occurs only in the steepest downslope direction from any given point; an mfd algorithm assumes that subsurface flow occurs in all downslope directions from any given point. The topographic index in TOPMODEL is ln (a/tan β), where In is the Napierian logarithm, a is the upslope area per unit contour length, and tan β is the slope gradient. The ln (a/tanβ) distributions were computed from digital elevation model (DEM) data for locations with diverse topography in Arizona, Colorado, Louisiana, Nebraska, North Carolina, Oregon, Pennsylvania, Tennessee, Vermont, and Virginia. The means of the ln (a/tan β) distributions were higher when the mfd algorithm was used for computation compared to when the sfd algorithm was used. The variances and skews of the distributions were lower for the mfd algorithm compared to the sfd algorithm. The differences between the mfd and sfd algorithms in the mean, variance, and skew of the ln (a/tan β) distribution were almost identical for the various DEMs and were not affected by DEM resolution or watershed size. TOPMODEL model efficiency and simulated flow paths were affected only slightly when the ln (a/tan β) distribution was computed with the sfd algorithm instead of the mfd algorithm. Any difference in the model efficiency and simulated flow paths between the sfd and mfd algorithms essentially disappeared when the model was calibrated by adjusting subsurface hydraulic parameters.

  8. Comparison of direct mercury analyzer and FIA-CV-AAS in determination of methylmercury in fish

    Science.gov (United States)

    Ulrich, J. C.; Hortellani, M. A.; Sarkis, J. E. S.; Nakatsubo, M. A.

    2016-07-01

    Methylmercury (MeHg) has been determined in fish reference materials by direct mercury analyzer (DMA 80) and FIA-CV-AAS. In order to evaluate accuracy, certified reference materials (Fish protein, NRCC - Dorm 4 and fish material, Ipen - Dourada 1) were analyzed after extraction and separation of mercury species. Good agreement of the results have been obtained (relative error of the determination between the methods varied from 1.5% to 39%). The repeatability of the results varied from 4% to 26%.

  9. RNase protection assays and RNA gel blots: a direct comparison of sensitivity.

    Science.gov (United States)

    Higgs, D C; Colbert, J T

    1992-01-01

    RNase protection assays are commonly thought to be a more sensitive means of detecting and quantitating specific mRNAs than are RNA gel blots (Northern blots). We have directly compared the sensitivity of these two approaches by assaying for known amounts of in vitro synthesized beta-glucuronidase mRNA. With the probes and protocols employed here, the ability to detect a specific mRNA was similar whether RNase protection or RNA gel blot analyses were performed.

  10. Direct Imaging of Extra-Solar Planets – Homogeneous Comparison of Detected Planets and Candidates

    OpenAIRE

    Neuhäuser, Ralph; Schmidt, Tobias

    2012-01-01

    Searching the literature, we found 25 stars with directly imaged planets and candidates. We gathered photometric and spectral information for all these objects to derive their luminosities in a homogeneous way, taking a bolometric correction into account. Using theoretical evolutionary models, one can then estimate the mass from luminosity, temperature, and age. According to our mass estimates, all of them can have a mass below 25 Jup masses, so that they are considered as planets.

  11. Comparisons of the Interstellar Magnetic Field Directions obtained from the IBEX Ribbon and Interstellar Polarizations

    CERN Document Server

    Frisch, Priscilla C; Berdyugin, Andrei; Funsten, Herbert O; Magalhaes, Mario; McComas, David J; Piirola, Vilppu; Schwadron, Nathan A; Slavin, Jonathan D; Wiktorowicz, Sloane J

    2010-01-01

    Variations in the spatial configuration of the interstellar magnetic field (ISMF) near the Sun can be constrained by comparing the ISMF direction at the heliosphere found from the Interstellar Boundary Explorer spacecraft (IBEX) observations of a 'Ribbon' of energetic neutral atoms (ENAs), with the ISMF direction derived from optical polarization data for stars within ~40 pc. Using interstellar polarization observations towards ~30 nearby stars within 90 deg of the heliosphere nose, we find that the best fits to the polarization position angles are obtained for a magnetic pole directed towards ecliptic coordinates of lambda, beta 263 deg, 37 deg (or galactic coordinates of L,B 38 deg, 23deg), with uncertainties of +/- 35 deg, based on the broad minimum of the best fits and the range of data quality. This magnetic pole is 33 deg from the magnetic pole that is defined by the center of the arc of the ENA Ribbon. The IBEX ENA ribbon is seen in sightlines that are perpendicular to the ISMF as it drapes over the he...

  12. Comparison of Sniffing Position and Simple Head Extension for Visualization of Glottis During Direct Laryngoscopy

    Directory of Open Access Journals (Sweden)

    Suresh Kumar Singhal

    2008-01-01

    Full Text Available The prospective randomized study comprised of 200 patients in the age group of 20 to 60 years, belonging to ASA physical status grade I or II, undergoing elective surgery under general anaesthesia with tracheal intubation. The aim was to compare sniffing position with simple head extension for visualization of glottis during direct laryngos-copy and ease of tracheal intubation. All the patients were randomly divided in two groups of 100 each: Group A (sniffing position and Group B (simple head extension. Direct laryngoscopy was done using Macintosh laryngo-scope (size 3 blade. Glottic visualization during laryngoscopy was assessed using modified Cormack and Lehane classification. After laryngoscopy, tracheal intubation was performed and intubation difficulty score (IDS recorded. Both groups were comparable regarding glottic visualization (P>0.05. All intubation difficulty score variables (N 1 to N 7 were comparable in the two groups except N 3 variable, which was significantly higher (P< 0.05 in simple head extension position. Total IDS was significantly better in sniffing position than simple head extension position (P< 0.05. To conclude, glottis visualization and intubation difficulty score are better in sniffing position as compared to simple head extension. It is too early to abandon this gold standard (sniffing position for direct laryngoscopy and tracheal intubation.

  13. A comparison of metal accumulation by the cnidarian Hydra vulgaris directly from water or

    Directory of Open Access Journals (Sweden)

    Wanchamai Karntanut

    2007-05-01

    Full Text Available The cnidarian Hydra has been widely used to assess the acute toxicity of freshwater pollutants, but very little is known about pollutant accumulation by this animal. The purpose of this study was to measurethe accumulation of the three metals, i.e., copper, cadmium and zinc directly from water and also via its prey and to relate the recorded tissue concentrations to any change in biological activities. It was found thatcopper, cadmium and zinc all were accumulated in the tissues of Hydra exposed directly to the metals in water and also those exposed indirectly through feeding on contaminated prey. The bioconcentration factor(BCF recorded at 48 hours following direct uptake from water was greatest for copper (773, followed by cadmium (409 and zinc (125, although the greatest increase in body burden occurred with cadmium, Metal body burdens of Hydra fed on contaminated prey (Artemia increased in the same metal sequence as fordirect uptake from water and the increase was highest (250 times that of control Hydra for cadmium; however, biomagnification factors (BMFs were all < 1.0 indicating that there was little potential for increasingaccumulation via the food chain. There was significant inhibition of regeneration and bud production in polyps which had fed on cadmium-containing Artemia but not on copper or zinc- containing Artemia.

  14. Loading applied on prosthetic knee of transfemoral amputee: comparison of inverse dynamics and direct measurements.

    Science.gov (United States)

    Dumas, R; Cheze, L; Frossard, L

    2009-11-01

    Inverse dynamics is the most comprehensive method that gives access to the net joint forces and moments during walking. However it is based on assumptions (i.e., rigid segments linked by ideal joints) and it is known to be sensitive to the input data (e.g., kinematic derivatives, positions of joint centres and centre of pressure, inertial parameters). Alternatively, transducers can be used to measure directly the load applied on the residuum of transfemoral amputees. So, the purpose of this study was to compare the forces and moments applied on a prosthetic knee measured directly with the ones calculated by three inverse dynamics computations--corresponding to 3 and 2 segments, and "ground reaction vector technique"--during the gait of one patient. The maximum RMSEs between the estimated and directly measured forces (i.e., 56 N) and moment (i.e., 5 N m) were relatively small. However the dynamic outcomes of the prosthetic components (i.e., absorption of the foot, friction and limit stop of the knee) were only partially assessed with inverse dynamic methods.

  15. Glucose, amino acids and fatty acids directly regulate ghrelin and NUCB2/nesfatin-1 in the intestine and hepatopancreas of goldfish (Carassius auratus) in vitro.

    Science.gov (United States)

    Bertucci, Juan Ignacio; Blanco, Ayelén Melisa; Canosa, Luis Fabián; Unniappan, Suraj

    2017-04-01

    Ghrelin and nesfatin-1 are two peptidyl hormones primarily involved in food intake regulation. We previously reported that the amount of dietary carbohydrates, protein and lipids modulates the expression of these peptides in goldfish in vivo. In the present work, we aimed to characterize the effects of single nutrients on ghrelin and nesfatin-1 in the intestine and hepatopancreas. First, immunolocalization of ghrelin and NUCB2/nesfatin-1 in goldfish hepatopancreas cells was studied by immunohistochemistry. Second, the effects of 2 and 4hour-long exposures of cultured intestine and hepatopancreas sections to glucose, l-tryptophan, oleic acid, linolenic acid (LNA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) on ghrelin and nesfatin-1 gene and protein expression were studied. Co-localization of ghrelin and NUCB2/nesfatin-1 in the cytoplasm of goldfish hepatocytes was found. Exposure to glucose led to an upregulation of preproghrelin and a downregulation of nucb2/nesfatin-1 in the intestine. l-Tryptophan mainly decreased the expression of both peptides in the intestine and hepatopancreas. Fatty acids, in general, downregulated NUCB2/nesfatin-1 in the intestine, but only the longer and highly unsaturated fatty acids inhibited preproghrelin. EPA exposure led to a decrease in preproghrelin, and an increase in nucb2/nesfatin-1 expression in hepatopancreas after 2h. These results show that macronutrients exert a dose- and time-dependent, direct regulation of ghrelin and nesfatin-1 in the intestine and hepatopancreas, and suggest a role for these hormones in the digestive process and nutrient metabolism.

  16. Direct Capture of Organic Acids From Fermentation Media Using Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Klasson, K.T.

    2004-11-03

    Several ionic liquids have been investigated for the extraction of organic acids from fermentation broth. Partitioning of representative organic acids (lactic, acetic, and succinic) between aqueous solution and nine hydrophobic ionic liquids was measured. The extraction efficiencies were strongly dependent on pH of the aqueous phase. Distribution coefficient was very good (approximately 60) at low succinic acid concentrations for one of the ionic liquids (trihexyltetradecylphosphonium methanesulfonate) at neutral pH. However, this ionic liquid had to be diluted with nonanol due to its high viscosity in order to be useful. A diluent (trioctylamine) was also added to this mixture. The results suggest that an extraction system based on ionic liquids may be feasible for succinic acid recovery from fermentation broth and that two ideal extraction stages are needed to reduce the concentration from 33 g/L to 1 g/L of succinic acid. Further studies are needed to evaluate other issues related to practical applications, including ionic liquid loss in the process, toxicity effects of ionic liquids during simultaneous fermentation and extractions.

  17. [Comparison of direct microscopy, culture, ELISA and molecular methods for diagnosis of Entamoeba histolytica].

    Science.gov (United States)

    Tüzemen, Nazmiye Ulkü; Doğan, Nihal

    2014-01-01

    Amebiasis, a parasitic infection caused by Entamoeba histolytica, is one of the most common parasitic infections worldwide. Since it is still an important public health problem in developing countries, rapid differential diagnosis of amebiasis is crucial in terms of treatment. The most frequently used method for laboratory diagnosis is direct microscopy, however more reliable and specific methods are needed in order to differentiate the apathogenic Entamoeba dispar under the microscope. This study was conducted to compare the results of different methods namely, direct microscopy, culture, ELISA and PCR for the detection of E.histolytica in stool samples and to evaluate the performances of those methods. A total of 1049 stool samples collected from pediatric and adult patients who were admitted to hospital with diarrhea complaint between January 2011-March 2013, and randomly selected samples from primary school children, were included in the study. Direct microscopic examination was performed by native-lugol, physiological saline, modified formol-ethyl acetate sedimentation and trichrome staining methods. The stool samples were also inoculated into TYI-S-33 media for axenic cultivation of amoeba. The presence of amebic antigens in the samples were screened by a commercial ELISA kit (TechLab, E.histolytica II, USA). For the molecular diagnosis, a multiplex tandem real-time PCR (MT-PCR) kit (AusDiagnostics Pty Ltd, Australia) was used, after the extraction of DNAs with QIAamp DNA Stool Mini Kit (Qiagen, USA). A total of 354 samples which could be evaluated by all of the methods, were included in the study. Of the 354 stool samples, 84 (23.7%) were found E.histolytica/E.dispar positive by direct microscopy, 61 (17.2%) by trichrome staining, 46 (12.9%) by culture, 31 (8.7%) by ELISA and 9 (2.5%) by MT-PCR. Of direct microscopy positive samples 54.7% (46/84) were also positive with trichrome staining, 39.3% (33/84) with culture, 15.5% (13/84) with ELISA and 7.1% (6

  18. Comparison of gas-phase acidities of some carbon acids with their rates of hydron exchange in methanolic methoxide

    NARCIS (Netherlands)

    DeTuri, V.F.; Koch, H.F.; Koch, J.G.; Lodder, G.; Mishima, M.; Zuilhof, H.; Abrams, N.M.; Anders, C.E.; Biffinger, J.C.; Han, P.; Kurland, A.R.; Nichols, J.M.; Ruminski, A.M.; Smith, P.R.; Vasey, K.D.J.

    2006-01-01

    Hydron exchange reaction rates, k(exch)M(-1) s(-1), using methanolic sodium methoxide are compared with gas-phase acidities, Delta G(Acid)(0) kcal/mol, for four 9-YPhenylfluorenes-9-H-i, seven (YC6H4CH)-H-i(CF3)(2), seven YC6H4-(CHClCF3)-H-i, and (C6F5H)-H-i. Fourteen of the fluorinated benzylic com

  19. A comparison of direct versus self-report measures for assessing physical activity in adults: a systematic review

    Directory of Open Access Journals (Sweden)

    Hardt Jill

    2008-11-01

    Full Text Available Abstract Background Accurate assessment is required to assess current and changing physical activity levels, and to evaluate the effectiveness of interventions designed to increase activity levels. This study systematically reviewed the literature to determine the extent of agreement between subjectively (self-report e.g. questionnaire, diary and objectively (directly measured; e.g. accelerometry, doubly labeled water assessed physical activity in adults. Methods Eight electronic databases were searched to identify observational and experimental studies of adult populations. Searching identified 4,463 potential articles. Initial screening found that 293 examined the relationship between self-reported and directly measured physical activity and met the eligibility criteria. Data abstraction was completed for 187 articles, which described comparable data and/or comparisons, while 76 articles lacked comparable data or comparisons, and a further 30 did not meet the review's eligibility requirements. A risk of bias assessment was conducted for all articles from which data was abstracted. Results Correlations between self-report and direct measures were generally low-to-moderate and ranged from -0.71 to 0.96. No clear pattern emerged for the mean differences between self-report and direct measures of physical activity. Trends differed by measure of physical activity employed, level of physical activity measured, and the gender of participants. Results of the risk of bias assessment indicated that 38% of the studies had lower quality scores. Conclusion The findings suggest that the measurement method may have a significant impact on the observed levels of physical activity. Self-report measures of physical activity were both higher and lower than directly measured levels of physical activity, which poses a problem for both reliance on self-report measures and for attempts to correct for self-report – direct measure differences. This review reveals

  20. Ligand-Directed Acid-Sensitive Amidophosphate 5‑Trifluoromethyl-2′-Deoxyuridine Conjugate as a Potential Theranostic Agent

    NARCIS (Netherlands)

    Godovikova, T.S.; Kaptein, R.; Silnikov, V.N.; et al., [No Value

    2013-01-01

    Herein, we report a novel strategy to engineer an acid-sensitive anticancer theranostic agent using a vector− drug ensemble. The ensemble was synthesized by directly conjugating the linoleic acid (LA)-modified branched polyethyleneimine with a chemotherapeutic drug trifluorothymidine. Linoleic acid

  1. Sensitive detection of nucleic acids by PNA hybridization directed co-localization of fluorescent beads

    DEFF Research Database (Denmark)

    Shiraishi, Takehiko; Deborggraeve, Stijn; Büscher, Philippe;

    2011-01-01

    We have designed a pair of biotinylated peptide nucleic acid (PNA) probes targeting two sequences in 18S rRNA (from the parasite Trypanosoma brucei) at a distance of 191 nt (corresponding to maximum distance of ca. 60 nm) from each other. The PNA probes were individually bound to (strept)avidin-c......We have designed a pair of biotinylated peptide nucleic acid (PNA) probes targeting two sequences in 18S rRNA (from the parasite Trypanosoma brucei) at a distance of 191 nt (corresponding to maximum distance of ca. 60 nm) from each other. The PNA probes were individually bound to (strept...

  2. Sport Education and Direct Instruction Units: Comparison of Student Knowledge Development in Athletics

    Science.gov (United States)

    Pereira, José; Araújo, Rui; Farias, Cláudio; Bessa, Cristiana; Mesquita, Isabel

    2016-01-01

    This study conducted a comparative analysis of students’ knowledge development on athletics in Sport Education and in a Direct Instruction unit taking into account sex and initial skill level. The participants were an experienced Physical Education teacher and two sixth-grade classes totaling 47 students (25 boys and 22 girls). Each class was randomly placed in either Sport Education or Direct Instruction classes and participated in 20, 45-minutes lessons focused on shot put, hurdles and triple jump. Knowledge on athletics was assessed through a 25-items written and video-based test. The inter-group differences and improvements across time in the knowledge test were analyzed through the Mann-Whitney and Wilcoxon tests, respectively. There were significant knowledge improvements in both instructional approaches irrespective of students’ gender and skill level. In Direct Instruction, the type of task organization, the high rates of repetition of movement patterns and feedback by the teacher were beneficial to student learning. In Sport Education, the autonomy granted to students in the control of the pace of task transitions by making on-going judgments on achievement of performance criteria, implicated students affectively and cognitively with the learning content. It was further supported that several models and teaching strategies should be taken into consideration when teaching Physical Education. Different approaches should be perceived as alternatives and teachers should retain the best in each according with the moment in the unit, student developmental stage, and the specific learning objectives in the task. Key points The results in this study showed that regardless of students’ sex, both DI and SE were efficient in the promotion of improvements in students’ content knowledge of athletics. Both boys and girls improved from the pre-test to the post-test in SE and DI. SE was particularly beneficial to lower skill-level. On the contrary, in the DI unit

  3. A comparison of microwave versus direct solar heating for lunar brick production

    Science.gov (United States)

    Yankee, S. J.; Strenski, D. G.; Pletka, B. J.; Patil, D. S.; Mutsuddy, B. C.

    1990-01-01

    Two processing techniques considered suitable for producing bricks from lunar regolith are examined: direct solar heating and microwave heating. An analysis was performed to compare the two processes in terms of the amount of power and time required to fabricate bricks of various sizes. Microwave heating was shown to be significantly faster than solar heating for rapid production of realistic-size bricks. However, the relative simplicity of the solar collector(s) used for the solar furnace compared to the equipment necessary for microwave generation may present an economic tradeoff.

  4. Wind gust measurements using pulsed Doppler wind-lidar: comparison of direct and indirect techniques

    DEFF Research Database (Denmark)

    model, driven by the Doppler lidar measurements, which uses a non-linear particle filter to estimate the small-scale turbulent fluctuations. The first results show that the reconstruction method can reproduce the wind speed maxima measured by the sonic anemometer if a low-pass filter with a cut......-off frequency similar to the lidar measurement frequency is applied to the sonic data. These results from the reconstructed wind are better than the maxima derived directly from the wind lidar measurements. However, the maxima of the raw sonic anemometer signal are still higher than the maxima...

  5. A comparison between two optimized TFPM geometries for 5 MW direct-drive wind turbines

    DEFF Research Database (Denmark)

    Nica, Florin Valentin Traian; Ritchie, Ewen; Leban, Krisztina Monika

    2013-01-01

    for the industry. The approach presented in this paper focuses on a reduction in mass of active materials, which constitute the generator, because the price of the machine is in direct relation with the amount of materials used for the construction. This strategy is applied for two types of TFPM geometries...... in order to asses which behaves better when subjected to optimization and which provides the best result. In order to obtain the mass of active materials the entire analytical design has to be covered, making the analytical design to behave as a cost function for the optimization program. The innovation...

  6. Follow the Leader: Preference for Specific Amino Acids Directly Following the Initial Methionine in Proteins of Different Organisms

    Institute of Scientific and Technical Information of China (English)

    Ronen Shemesh; Amit Novik; Yossi Cohen

    2010-01-01

    It is well established that the vast majority of proteins of all taxonomical groups and species are initiated by an AUG codon,translated into the amino acid methionine(Met).Many attempts were made to evaluate the importance of the sequences surrounding the initiation codon,mostly focusing on the RNA sequence.However,the role and importance of the amino acids following the initiating Met residue were rarely investigated,mostly in bacteria and fungi.Herein,we computationally examined the protein sequences of all major taxonomical groups represented in the Swiss-Prot database,and evaluated the preference of each group to specific amino acids at the positions directly following the initial Met.The results indicate that there is a species-specific preference for the second amino acid of the majority of protein sequences.Interestingly,the preference for a certain amino acid at the second position changes throughout evolution from lysine in prokaryotes,through serine in lower eukaryotes,to alanine in higher plants and animals.

  7. Hydroxycinnamic acids are ester-linked directly to glucosyl moieties within the lignan macromolecule from flaxseed hulls.

    Science.gov (United States)

    Struijs, Karin; Vincken, Jean-Paul; Verhoef, René; Voragen, Alphons G J; Gruppen, Harry

    2008-03-01

    In flaxseed hulls, lignans are present in an oligomeric structure. Secoisolariciresinol diglucoside (SDG), ester-linked to hydroxy-methyl-glutaric acid (HMGA), forms the backbone of this lignan macromolecule. The hydroxycinnamic acids p-coumaric acid glucoside (CouAG) and ferulic acid glucoside (FeAG) are also part of the lignan macromolecule. However, their position and type of linkage are still unknown. The aim of this study was to investigate how CouAG and FeAG are linked within the lignan macromolecule from flaxseed hulls. Fragments of the lignan macromolecule were obtained by partial saponification. After isolation of the fragments by preparative RP-HPLC, several key structures were identified by MS and NMR. Within the lignan macromolecule, CouAG is attached to the C-6 position of a glucosyl moiety of SDG. FeA is linked to the C-2 position of a glucosyl moiety of SDG. FeAG is ester-linked within the lignan macromolecule with its carboxyl group, but it remains unclear whether FeAG links to the C-2 or C-6 position of SDG. Attachment of HMGA to the glucosyl moiety of CouAG or FeAG was not observed. The results clearly show that within the lignan macromolecule, the hydroxycinnamic acids are linked directly via an ester bond to the glucosyl moiety of SDG.

  8. Direct chromatographic enantioresolution of fully constrained β-amino acids: exploring the use of high-molecular weight chiral selectors.

    Science.gov (United States)

    Sardella, Roccaldo; Ianni, Federica; Lisanti, Antonella; Scorzoni, Stefania; Marini, Francesca; Sternativo, Silvia; Natalini, Benedetto

    2014-05-01

    To the best of our knowledge enantioselective chromatographic protocols on β-amino acids with polysaccharide-based chiral stationary phases (CSPs) have not yet appeared in the literature. Therefore, the primary objective of this work was the development of chromatographic methods based on the use of an amylose derivative CSP (Lux Amylose-2), enabling the direct normal-phase (NP) enantioresolution of four fully constrained β-amino acids. Also, the results obtained with the glycopeptide-type Chirobiotic T column employed in the usual polar-ionic (PI) mode of elution are compared with those achieved with the polysaccharide-based phase. The Lux Amylose-2 column, in combination with alkyl sulfonic acid containing NP eluent systems, prevailed over the Chirobiotic T one, when used under the PI mode of elution, and hence can be considered as the elective choice for the enantioseparation of this class of rigid β-amino acids. Moreover, the extraordinarily high α (up to 4.60) and R S (up to 10.60) values provided by the polysaccharidic polymer, especially when used with camphor sulfonic acid containing eluent systems, make it also suitable for preparative-scale enantioisolations.

  9. A Performance Comparison of Different Graphics Processing Units Running Direct N-Body Simulations

    CERN Document Server

    Capuzzo-Dolcetta, Roberto

    2013-01-01

    Hybrid computational architectures based on the joint power of Central Processing Units and Graphic Processing Units (GPUs) are becoming popular and powerful hardware tools for a wide range of simulations in biology, chemistry, engineering, physics, etc.. In this paper we present a comparison of performance of various GPUs available on market when applied to the numerical integration of the classic, gravitational, N-body problem. To do this, we developed an OpenCL version of the parallel code (HiGPUs) to use for these tests, because this version is the only apt to work on GPUs of different makes. The main general result is that we confirm the reliability, speed and cheapness of GPUs when applied to the examined kind of problems (i.e. when the forces to evaluate are dependent on the mutual distances, as it happens in gravitational physics and molecular dynamics). More specifically, we find that also the cheap GPUs built to be employed just for gaming applications are very performant in terms of computing speed...

  10. A direct comparison of remote sensing approaches for high-throughput phenotyping in plant breeding

    Directory of Open Access Journals (Sweden)

    Maria Tattaris

    2016-08-01

    Full Text Available Remote sensing (RS of plant canopies permits non-intrusive, high-throughput monitoring of plant physiological characteristics. This study compared three RS approaches using a low flying UAV (unmanned aerial vehicle, with that of proximal sensing, and satellite-based imagery. Two physiological traits were considered, canopy temperature (CT and a vegetation index (NDVI, to determine the most viable approaches for large scale crop genetic improvement. The UAV-based platform achieves plot-level resolution while measuring several hundred plots in one mission via high-resolution thermal and multispectral imagery measured at altitudes of 30-100 m. The satellite measures multispectral imagery from an altitude of 770 km. Information was compared with proximal measurements using IR thermometers and an NDVI sensor at a distance of 0.5-1m above plots. For robust comparisons, CT and NDVI were assessed on panels of elite cultivars under irrigated and drought conditions, in different thermal regimes, and on un-adapted genetic resources under water deficit. Correlations between airborne data and yield/biomass at maturity were generally higher than equivalent proximal correlations. NDVI was derived from high-resolution satellite imagery for only larger sized plots (8.5 x 2.4 m due to restricted pixel density. Results support use of UAV-based RS techniques for high-throughput phenotyping for both precision and efficiency.

  11. Functional comparison of annexin V analogues labeled indirectly and directly with iodine-124

    Energy Technology Data Exchange (ETDEWEB)

    Dekker, Bronwen [CRUK/UMIST Dept. of Radiochemical Targeting and Imaging, Paterson Inst. for Cancer Research, M20 4BX Manchester (United Kingdom)]|[Dept. of Instrumentation and Analytical Science, Univ. of Manchester Inst. for Science and Technology (United Kingdom)]. E-mail: bdekker@picr.man.ac.uk; Keen, Heather [CRUK/UMIST Dept. of Radiochemical Targeting and Imaging, Paterson Inst. for Cancer Research, M20 4BX Manchester (United Kingdom)]|[Dept. of Instrumentation and Analytical Science, Univ. of Manchester Inst. for Science and Technology, M60 1QD Manchester (United Kingdom); Shaw, David [CRUK/UMIST Dept. of Radiochemical Targeting and Imaging, Paterson Inst. for Cancer Research, M20 4BX Manchester (United Kingdom)]|[CRUK Dept. of Immunology, Paterson Inst. for Cancer Research, M20 4BX Manchester (United Kingdom); Disley, Lynn [CRUK/UMIST Dept. of Radiochemical Targeting and Imaging, Paterson Inst. for Cancer Research, M20 4BX Manchester (United Kingdom); Hastings, David; Julyan, Peter [CRUK/UMIST Dept. of Radiochemical Targeting and Imaging, Paterson Inst. for Cancer Research, M20 4BX Manchester (United Kingdom)]|[North Western Medical Physics, Christie Hospital NHS Trust, M20 4BX Manchester (United Kingdom); Hadfield, John [School of Environment and Life Sciences, Univ. of Salford, M5 4WT Manchester (United Kingdom); Reader, Andrew [Dept. of Instrumentation and Analytical Science, Univ. of Manchester Inst. for Science and Technology, M60 1QD Manchester (United Kingdom); Allan, Donald [Physics and Electronic Unit, Paterson Inst. for Cancer Research, M20 4BX Manchester (United Kingdom); Watson, Alastair [Dept. of Medicine, Univ of Liverpool (United Kingdom); Zweit, Jamal [CRUK/UMIST Dept. of Radiochemical Targeting and Imaging, Paterson Inst. for Cancer Research, M20 4BX Manchester (United Kingdom)]|[Dept. of Instrumentation and Analytical Science, Univ. of Manchester Inst. for Science and Technology (United Kingdom)]. E-mail: jzweit@picr.man.ac.uk

    2005-05-01

    We are interested in imaging cell death in vivo using annexin V radiolabeled with {sup 124}I. In this study, [{sup 124}I]4IB-annexin V and [{sup 124}I]4IB-ovalbumin were made using [{sup 124}I]N-hydroxysuccinimidyl-4-iodobenzoate prepared by iododestannylation of N-hydroxysuccinimidyl-4-(tributylstannyl)benzoate. [{sup 124}I]4IB-annexin V binds to phosphatidylserine-coated microtiter plates and apoptotic Jurkat cells and accumulates in hepatic apoptotic lesions in mice treated with anti-Fas antibody, while [{sup 124}I]4IB-ovalbumin does not. In comparison with {sup 124}I-annexin V, [{sup 124}I]4IB-annexin V has a higher rate of binding to phosphatidylserine in vitro, a higher kidney and urine uptake, a lower thyroid and stomach content uptake, greater plasma stability and a lower rate of plasma clearance. Binding of radioactivity to apoptotic cells relative to normal cells in vitro and in vivo appears to be lower for [{sup 124}I]4IB-annexin V than for {sup 124}I-annexin V.

  12. A Direct Comparison of Remote Sensing Approaches for High-Throughput Phenotyping in Plant Breeding

    Science.gov (United States)

    Tattaris, Maria; Reynolds, Matthew P.; Chapman, Scott C.

    2016-01-01

    Remote sensing (RS) of plant canopies permits non-intrusive, high-throughput monitoring of plant physiological characteristics. This study compared three RS approaches using a low flying UAV (unmanned aerial vehicle), with that of proximal sensing, and satellite-based imagery. Two physiological traits were considered, canopy temperature (CT) and a vegetation index (NDVI), to determine the most viable approaches for large scale crop genetic improvement. The UAV-based platform achieves plot-level resolution while measuring several hundred plots in one mission via high-resolution thermal and multispectral imagery measured at altitudes of 30–100 m. The satellite measures multispectral imagery from an altitude of 770 km. Information was compared with proximal measurements using IR thermometers and an NDVI sensor at a distance of 0.5–1 m above plots. For robust comparisons, CT and NDVI were assessed on panels of elite cultivars under irrigated and drought conditions, in different thermal regimes, and on un-adapted genetic resources under water deficit. Correlations between airborne data and yield/biomass at maturity were generally higher than equivalent proximal correlations. NDVI was derived from high-resolution satellite imagery for only larger sized plots (8.5 × 2.4 m) due to restricted pixel density. Results support use of UAV-based RS techniques for high-throughput phenotyping for both precision and efficiency. PMID:27536304

  13. Comparison of Calcium Hydroxide and Bioactive Glass after Direct Pulp Capping in Primary Teeth

    Directory of Open Access Journals (Sweden)

    R. Haghgoo

    2007-12-01

    Full Text Available Objective: Bioactive glass is often used as a filler material for repair of dental bone defects.In different studies osteogenic potential of this material was proved, but its dentinogenesisproperty is in doubt. The purpose of this study was to evaluate the histological pulp responses of Calcium hydroxide and Bioactive glass placed directly on exposed pulp tissues.Materials and Methods: Twenty teeth to be extracted due to orthodontic reasons were selected. These teeth were divided into two groups and treated with direct pulp capping.Calcium hydroxide was used for 10 teeth and Bioactive glass for 10 teeth. After 60 daysthe teeth were extracted and prepared for histological evaluation. Finally the data was analyzed with exact Fisher test.Results: All teeth treated with Calcium hydroxide showed inflammation. Internal resorption was seen in six teeth, abscess in five teeth and dentinal bridge in two teeth. Inflammationwas seen in three Bioactive glass samples and dentinal bridge in seven teeth, but internal resorption and abscess were not seen.Conclusion: Bioactive glass appears to be superior to Calcium hydroxide as a pulp capping agent in primary teeth.

  14. A comparison of direct and indirect laryngoscopes and the ILMA in novice users: a manikin study.

    LENUS (Irish Health Repository)

    Maharaj, C H

    2007-11-01

    Direct laryngoscopic tracheal intubation using the Macintosh laryngoscope is taught to many healthcare professionals as it is a potentially life-saving procedure. However, it is a difficult skill to acquire and maintain. Several alternative intubation devices exist that may provide a better view of the glottis and require less skill to use. We conducted a prospective, randomised trial of four different laryngoscopes and the ILMA in 30 medical students who had no prior airway management experience. The devices were tested in both normal and cervical immobilisation laryngoscopy scenarios. Following brief didactic instruction, each participant took turns performing laryngoscopy and intubation using each device under direct supervision. Each student was allowed up to three intubation attempts with each device, in each scenario. The Airtraq, McCoy, and the ILMA each demonstrated advantages over the Macintosh laryngoscope. In both the easy and difficult airway scenarios, the Airtraq, McCoy, and the ILMA reduced the number of intubation attempts, and reduced the number of optimisation manoeuvres required. The Airtraq and ILMA reduced the severity of dental trauma in both scenarios. The performance of the other devices studied was more variable. Overall, participants found that only the Airtraq was less difficult to use and they were more confident using it compared to the Macinosh laryngoscope.

  15. Comparison of blind intubation through supraglottic devices and direct laryngoscopy by novices: a simulation manikin study

    Science.gov (United States)

    Kim, Young Yong; Kang, Gu Hyun; Kim, Won Hee; Choi, Hyun Young; Jang, Yong Soo; Lee, Young Jae; Kim, Jae Guk; Kim, Hyeongtae; Kim, Gyoung Yong

    2016-01-01

    Objective This study aimed to compare intubation performance between blind intubation through supraglottic airway devices and direct laryngoscopy by novices under manikin simulation. We hypothesized that the intubation time by novices using supraglottic airway devices was superior to that with the Macintosh laryngoscope (MCL). Methods A prospective, randomized crossover study was conducted with 95 participants, to evaluate i-gel, air-Q, LMA Fastrach, and MCL devices. Primary outcomes were the intubation time and the success rate for intubation. Results The i-gel showed the shortest insertion and tube passing time among the four devices; the i-gel and air-Q also showed the shortest total intubation time (all P<0.0083; i-gel vs. air-Q, P=0.03). The i-gel and MCL showed the highest cumulative success rate (all P<0.0083; i-gel vs. MCL, P=0.12). Conclusion Blind intubation through the i-gel showed almost equal intubation performance compared to direct laryngoscopy.

  16. COMPARISON OF SIX COMMERCIALLY-AVAILABLE DNA POLYMERASES FOR DIRECT PCR

    Directory of Open Access Journals (Sweden)

    Masashi Miura

    2013-12-01

    Full Text Available SUMMARY The use of a “direct PCR” DNA polymerase enables PCR amplification without any prior DNA purification from blood samples due to the enzyme's resistance to inhibitors present in blood components. Such DNA polymerases are now commercially available. We compared the PCR performance of six direct PCR-type DNA polymerases (KOD FX, Mighty Amp, Hemo KlenTaq, Phusion Blood II, KAPA Blood, and BIOTAQ in dried blood eluted from a filter paper with TE buffer. GoTaq Flexi was used as a standard DNA polymerase. PCR performance was evaluated by a nested PCR technique for detecting Plasmodium falciparum genomic DNA in the presence of the blood components. Although all six DNA polymerases showed resistance to blood components compared to the standard Taq polymerase, the KOD FX and BIOTAQ DNA polymerases were resistant to inhibitory blood components at concentrations of 40%, and their PCR performance was superior to that of other DNA polymerases. When the reaction mixture contained a mild detergent, only KOD FX DNA polymerase retained the original amount of amplified product. These results indicate that KOD FX DNA polymerase is the most resistant to inhibitory blood components and/or detergents. Thus, KOD FX DNA polymerase could be useful in serological studies to simultaneously detect antibodies and DNA in eluents for antibodies. KOD FX DNA polymerase is thus not limited to use in detecting malaria parasites, but could also be employed to detect other blood-borne pathogens.

  17. Comparison of conventional and directional freezing for the cryopreservation of human umbilical vein endothelial cells

    Institute of Scientific and Technical Information of China (English)

    Bing; Qi; Qing-Shan; Ji; Guang-Hui; Hou; Liu; Li; Xian-Fen; Cao; Jing; Wu

    2014-01-01

    AIM:To compare conventional slow equilibrium cooling and directional freezing(DF) by gauze package for cryopreservation of human umbilical vein endothelial cells(HUVECs).METHODS:HUVECs were randomly assigned to conventional freezing(CF) and DF by gauze package group. The two groups of HUVECs were incubated with a freezing liquid consisting of 10% dimethylsulfoxide(DMSO), 60% fetal bovine serum(FBS) and 30%Dulbecco’s modified Eagle’s medium(DMEM) and then put into cryopreserved tubes. CF group, slow equilibrium cooling was performed with the following program:precool in 4℃ for 30 min,-20℃ for 1h, and then immersion in-80℃ refrigerator. DF group, the tubes were packaged with gauze and then directional freezing in-80℃ refrigerator straightly. One month later, the vitality of HUVECs were calculated between two groups.RESULTS:There was no significant difference in the survival rate and growth curve between CF and DF groups. The DF group was significantly better than CFgroup in adherent rates, morphological changes and proliferative ability.CONCLUSION:In the conventional cryopreserved method, cells are slow equilibrium cooling by steps(4℃,-20℃ and finally-80℃), which is a complicated and time-consuming process. But the improved DF by gauze package method is better than conventional method, for which is convenient and easy to operate.

  18. Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system

    Science.gov (United States)

    Mounier, S.; Nicolodelli, G.; Redon, R.; Milori, D. M. B. P.

    2017-04-01

    The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model.

  19. Direct Synthesis of Hyperbranched Poly(acrylic acid-co-3-hydroxypropionate

    Directory of Open Access Journals (Sweden)

    Efkan Çatıker

    2015-01-01

    Full Text Available Hyperbranched poly(acrylic acid-co-3-hydroxypropionate (PAcHP was synthesized by base-catalyzed hydrogen transfer polymerization of acrylic acid through one step. The copolymers obtained through solution and bulk polymerization were insoluble in water and all organic solvents tried. Structural and compositional characterizations of hyperbranched PAcHP were performed by using FTIR, solid 13C-NMR, TGA, and titrimetric analysis. Acrylate fraction of the hyperbranched PAcHP obtained via bulk polymerization was determined as 60–65% by comparing TGA curves of hyperbranched PAcHP and pure poly(3-hydroxy propionate (PHP. However, analytical titration of the same sample revealed that acrylic acid units were about 47.3%. The results obtained from TGA and analytical titration were used to evaluate the chemical structure of the copolymer. Hyperbranched PAcHP exhibited hydrogel properties. Swelling behavior of the copolymer was investigated at a wide pH range and ionic strength. The dynamic swelling profiles of hyperbranched PAcHP exhibited a fast swelling behavior in the first hour and achieved the equilibrium state within 12 h in PBS. Depending on the conditions, the copolymers exhibited swelling ratios up to 2100%. As the copolymer has easily biodegradable propionate and versatile functional acrylic acid units, it can be used as not only biodegradable material in medical applications but also raw material in personal care commodities.

  20. Ascorbic acid, cognitive function, and Alzheimer’s disease: a current review and future direction

    OpenAIRE

    Bowman, Gene L.

    2012-01-01

    This narrative review appraises the human and animal studies implicating ascorbic acid (AA) in normal cognitive function and Alzheimer’s disease. A research framework for how nutrition affects brain aging is proposed with emphasis on AA intake, status, metabolism, and transport into brain tissue. A final synopsis highlights areas for future research regarding AA nourishment and healthy brain aging.

  1. Direct solid surface fluorescence spectroscopy of standard chemicals and humic acid in ternary system.

    Science.gov (United States)

    Mounier, S; Nicolodelli, G; Redon, R; Milori, D M B P

    2017-04-15

    The front face fluorescence spectroscopy is often used to quantify chemicals in well-known matrices as it is a rapid and powerful technique, with no sample preparation. However it was not used to investigate extracted organic matter like humic substances. This work aims to fully investigate for the first time front face fluorescence spectroscopy response of a ternary system including boric acid, tryptophan and humic substances, and two binaries system containing quinine sulfate or humic substance in boric acid. Pure chemicals, boric acid, tryptophan, quinine sulfate and humic acid were mixed together in solid pellet at different contents from 0 to 100% in mass. The measurement of excitation emission matrix of fluorescence (3D fluorescence) and laser induced fluorescence were then done in the front face mode. Fluorescence matrices were decomposed using the CP/PARAFAC tools after scattering treatments. Results show that for 3D fluorescence there is no specific component for tryptophan and quinine sulfate, and that humic substances lead to a strong extinction effect for mixture containing quinine sulfate. Laser induced fluorescence gives a very good but non-specific related response for both quinine sulfate and tryptophan. No humic substances fluorescence response was found, but extinction effect is observed as for 3D fluorescence. This effect is stronger for quinine sulfate than for tryptophan. These responses were modeled using a simple absorbance versus emission model.

  2. Direct monophasic replacement of fatty acid by DMSA on SPION surface

    Energy Technology Data Exchange (ETDEWEB)

    Gogoi, M. [Department of Physics, Tezpur University (Central University), Tezpur 784028 (India); Deb, P., E-mail: pdeb@tezu.ernet.in [Department of Physics, Tezpur University (Central University), Tezpur 784028 (India); Interface Chemistry and Surface Engineering, Max-Planck-Institut fuer Eisenforschung GmbH, Max-Planck-Strasse 1, 40237 Duesseldorf (Germany); Vasan, G.; Keil, P.; Kostka, A.; Erbe, A. [Interface Chemistry and Surface Engineering, Max-Planck-Institut fuer Eisenforschung GmbH, Max-Planck-Strasse 1, 40237 Duesseldorf (Germany)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Monophasic replacement of fatty acid coating. Black-Right-Pointing-Pointer Ultrastable dispersion of hydrophilic SPION in a wide pH range. Black-Right-Pointing-Pointer Unaltered microstructure and property on surface modification. - Abstract: Tailoring the surface and understanding the surface characteristics is necessary for biomedical applications of superparamagnetic nanoparticles. In this paper, superparamagnetic iron oxide nanoparticles (SPIONs) were prepared by thermal decomposition of iron nitrate in presence of stearic acid as surfactant. Due to the multilayer organization of surfactant molecules over the nanoparticle surface, the surface potential can be tuned by pH changes and hence the nanoparticles can be made dispersible in nonpolar as well as in polar solvents. We have presented a simple, facile procedure for controlled replacement of stearic acid from maghemite surface and subsequent derivatization by biocompatible dimercaptosuccinic acid (DMSA) to obtain ultrastable hydrophilic nanoparticles with unaltered morphology, phase and properties. The surface chemistry of the functionalized SPIONs was analyzed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) revealing the presence of bound and unbound thiol groups and disulfides, leading to its prolonged stability in aqueous medium. The consequence of spatially selective functionalization on the stability and solubility of surface hydrophilic SPION has also been realized.

  3. Comparison between electrocoagulation and chemical precipitation for metals removal from acidic soil leachate.

    Science.gov (United States)

    Meunier, Nathalie; Drogui, Patrick; Montané, Camille; Hausler, Robert; Mercier, Guy; Blais, Jean-François

    2006-09-01

    This paper provides a quantitative comparison between electrocoagulation and chemical precipitation based on heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) removal from acidic soil leachate (ASL) at the laboratory pilot scale. Chemical precipitation was evaluated using either calcium hydroxide or sodium hydroxide, whereas electrocoagulation was evaluated via an electrolytic cell using mild steel electrodes. Chemical precipitation was as effective as electrocoagulation in removing metals from ASL having low contamination levels (30 mg Pbl(-1) and 18 mg Znl(-1)). For ASL enriched with different metals (each concentration of metals was initially adjusted to 100 mg l(-1)), the residual Cr, Cu, Pb and Zn concentrations at the end of the experiments were below the acceptable level recommended for discharge in sewage urban works (more than 99.8% of metal was removed) using either electrocoagulation or chemical precipitation. Cd was more effectively removed by electrochemical treatment, whereas Ni was easily removed by chemical treatment. The cost for energy, chemicals and disposal of metallic residue of electrocoagulation process ranged from USD 8.83 to 13.95 tds(-1), which was up to five times lower than that recorded using chemical precipitation. Highly effective electrocoagulation was observed as the ASL was specifically enriched with high concentration of Pb (250-2000 mg Pbl(-1)). More than 99.5% of Pb was removed regardless of the initial Pb concentration imposed in ASL and, in all cases, the residual Pb concentrations (0.0-1.44 mg l(-1)) were below the limiting value (2.0 mg l(-1)) for effluent discharge in sewage works.

  4. Role of boric acid in nickel nanotube electrodeposition: a surface-directed growth mechanism.

    Science.gov (United States)

    Graham, Lauren M; Cho, Seungil; Kim, Sung Kyoung; Noked, Malachi; Lee, Sang Bok

    2014-01-18

    Nickel nanotubes have been synthesized by the popular and versatile method of template-assisted electrodeposition, and a surface-directed growth mechanism based on the adsorption of the nickel-borate complex has been proposed.

  5. Gamma-aminobutyric acid and GABAA receptors are involved in directional selectivity of pretectal neurons in pigeons

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The present study describes the effects of gamma-aminobutyric acid (GABA) and itsantagonists, bicuculline and 2-hydroxysaclofen, on visual responses of neurons in the pigeon nucleuslentiformis mesencephali (nLM). The results indicate that GABA significantly reduces bothspontaneous activity and visual responsiveness, and GABAA antagonist bicuculline but not GABABantagonist 2-hydroxysaclofen enhances visual responses of nLM cells examined. Furthermore,inhibition produced by motion in the null-direction of pretectal neurons is diminished by bicucullinebut not by 2-hydroxysaclofen. It is therefore concluded that the null-direction inhibition of directionalcells in the pigeon nLM is predominantly mediated by GABA and GABAA receptors. This inhibitionmay at least in part underlie directional asymmetry of optokinetic responses.

  6. Accurate Clock Period Comparison for PLL Using Phase-Shift Direction Detector

    Science.gov (United States)

    Makihara, Yukinobu; Ikebe, Masayuki; Motohisa, Junichi; Sano, Eiichi

    We proposed a new architecture for a phase-locked loop (PLL) obtained by comparing clock periods. We evaluated the use of a clock-period comparator (CPC) for the digitally controlled PLL we propose, where only the frequency should be locked. However, frequency control with the CPC resulted in the phase being locked. Thus, phase-lock operation was also achieved. The theoretical analysis of the phase-lock mechanism was confirmed through system simulations. We discussed about dead-zone problem caused by a time delay of circuits. We evaluated phase-shift direction detector to solve the dead zone problem. We designed the element blocks of the new PLL using a 0.25-μm CMOS process. We confirmed phase-lock operation through SPICE simulations of the MOSFET level. Moreover, we manufactured a trial circuit for the new PLL. We also confirmed phase-lock operation in the proposed PLL through measurements.

  7. Optical intensity modulation direct detection versus heterodyne detection: A high-SNR capacity comparison

    KAUST Repository

    Chaaban, Anas

    2016-09-15

    An optical wireless communications system which employs either intensity-modulation and direct-detection (IM-DD) or heterodyne detection (HD) is considered. IM-DD has lower complexity and cost than HD, but on the other hand, has lower capacity. It is therefore interesting to investigate the capacity gap between the two systems. The main focus of this paper is to investigate this gap at high SNR. Bounds on this gap are established for two cases: between IM-DD and HD, and between IM-DD and an HD-PAM which is an HD system employing pulse-amplitude modulation (PAM). While the gap between IM-DD and HD increases as the signal-to-noise ratio (SNR) increases, the gap between IM-DD and an HD-PAM is upper bounded by a constant at high SNR. © 2015 IEEE.

  8. Comparison of Direct Eulerian Godunov and Lagrange Plus Remap, Artificial Viscosity Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Pember, R B; Anderson, R W

    2001-03-30

    The authors compare two algorithms for solving the equations of unsteady inviscid compressible flow in an Eulerian frame: a staggered grid, Lagrange plus remap artificial viscosity scheme and a cell-centered, direct Eulerian higher-order Godunov scheme. They use the two methods to compute solutions to a number of one- and two-dimensional problems. The results show the accuracy of the two schemes to be generally equivalent. In a 1984 survey paper by Woodward and Colella, the Lagrange plus remap approach did not compare favorably with the higher-order Godunov methodology. They examine, therefore, how certain features of the staggered grid scheme considered here contribute to its improved accuracy. The critical features are shown to be the use of a monotonic artificial viscosity in the Lagrange step and, in the remap step, the use of a corner transport upwind scheme with van Leer limiters in conjunction with separate advection of internal and kinetic energies.

  9. Comparison of transcatheter laser and direct-current shock ablation of endocardium near tricuspid anulus

    Science.gov (United States)

    Zhang, Yu-Zhen; Wang, Shi-Wen; Li, Junheng

    1993-03-01

    Forty to eighty percent of the patients with accessory pathways (APs) manifest themselves by tachyarrhythmias. Many of these patients needed either life-long medical therapy or surgery. In order to avoid the discomfort and expenses in surgical procedures, closed chest percutaneous catheter ablation of APs became a potentially desirable therapeutic approach. Many investigations indicated that ablation of right APs by transcatheter direct current (dc) shock could cause life-threatening arrhythmias, right coronary arterical (RCA) spasm, etc. With the development of transcatheter laser technique, it has been used in drug-incurable arrhythmias. The results show that laser ablation is much safer than surgery and electric shock therapy. The purpose of this study is to explore the effectiveness, advantages, and complications with transcatheter Nd:YAG laser and dc shock in the ablation of right atrioventricular accessory pathways in the atrium near the tricuspid annulus (TA) in 20 dogs.

  10. Theoretic derivation of directed acyclic subgraph algorithm and comparisons with message passing algorithm

    Science.gov (United States)

    Ha, Jeongmok; Jeong, Hong

    2016-07-01

    This study investigates the directed acyclic subgraph (DAS) algorithm, which is used to solve discrete labeling problems much more rapidly than other Markov-random-field-based inference methods but at a competitive accuracy. However, the mechanism by which the DAS algorithm simultaneously achieves competitive accuracy and fast execution speed, has not been elucidated by a theoretical derivation. We analyze the DAS algorithm by comparing it with a message passing algorithm. Graphical models, inference methods, and energy-minimization frameworks are compared between DAS and message passing algorithms. Moreover, the performances of DAS and other message passing methods [sum-product belief propagation (BP), max-product BP, and tree-reweighted message passing] are experimentally compared.

  11. Comparison between the Direct Dyeing Kinetics of Bamboo and Conventional Viscose Fibers

    Institute of Scientific and Technical Information of China (English)

    CAO Ji-liang; TANG Ren-cheng; CHEN Wen-jang

    2010-01-01

    Two direct dyes were applied to conventional viscose(CV)and bamboo viscose(BV)fibers,which were prepared from bamboo cellulose pulps,and the dyeing kinetics of two fibers were compared.Three kinetic equations,namely Chrastil,Cegarra-Puente,and Vickerstaff,were used to fit the experimental dyeing rate points,showing that the best result was obtained by the Chrastil equation.BV fibers displayed slightly higher dyeing rates and dye adsorption values at initial stages,but a bit lower dye adsorption values at equilibrium than CV fibers.Furthermore,the dyeing of BV fibers exhibited lower activation energies and higher dyeing rate constants than that of CV fibers,and therefore showed slightly lower dependence on temperature.

  12. Production of high-oleic acid tallow fractions using lipase-catalyzed directed interesterification, using both batch and continuous processing.

    Science.gov (United States)

    MacKenzie; Stevenson

    2000-08-01

    Immobilized lipases were used to catalyze batch-directed interesterification of tallow, resulting in oleins containing significantly higher levels of unsaturated fatty acids than obtained by fractionation without lipase. After 14 days, a reaction catalyzed by 2% Novozym 435 yielded 57% olein unsaturation, compared with 45% in a no-enzyme control. Free fatty acid levels increased to 2-3% during reactions. Incubation of the enzyme in multiple batches of melted fat caused a gradual loss of interesterification activity, apparently due to progressive dehydration. The activity could be restored by addition of water to the reaction medium. Immobilized lipase was also used to catalyze directed interesterification in a continuous flow reactor. Melted tallow was circulated through a packed bed enzyme reactor and a separate crystallization vessel. The temperatures of the two parts of the apparatus were controlled separately to allow crystallization to occur separately from interesterification. Operation of the reactor with conventionally dry, prefractionated tallow allowed the formation of an olein consisting of up to 60% unsaturated fatty acids. The greatest changes in olein fatty acid composition were achieved when the fractionation temperature was kept constant at a value that promoted selective crystallization of trisaturated triglycerides that were continuously produced by enzymic interesterification. The enzyme could be reused without apparent loss of activity, and its activity was apparently enhanced by preincubation in melted tallow for up to several days. Control of both the water activity of the enzyme and tallow feedstock and of the absorption of atmospheric water vapor were required to maintain enzyme activity, during multiple reuse and minimize free fatty acid formation. This method may form the basis for a process to produce highly mono-unsaturated tallow fractions for use in food applications (e.g. frying) where a "healthy" low saturated fat product is required.

  13. Direct costs of asthma in Brazil: a comparison between controlled and uncontrolled asthmatic patients

    Directory of Open Access Journals (Sweden)

    L.A. Santos

    2007-07-01

    Full Text Available Asthma is a common chronic illness that imposes a heavy burden on all aspects of the patient's life, including personal and health care cost expenditures. To analyze the direct cost associated to uncontrolled asthma patients, a cross-sectional study was conducted to determine costs related to patients with uncontrolled and controlled asthma. Uncontrolled patient was defined by daytime symptoms more than twice a week or nocturnal symptoms during two consecutive nights or any limitations of activities, or need for relief rescue medication more than twice a week, and an ACQ score less than 2 points. A questionnaire about direct cost stratification in health services, including emergency room visits, hospitalization, ambulatory visits, and asthma medications prescribed, was applied. Ninety asthma patients were enrolled (45 uncontrolled/45 controlled. Uncontrolled asthmatics accounted for higher health care expenditures than controlled patients, US$125.45 and US$15.58, respectively [emergency room visits (US$39.15 vs US$2.70 and hospitalization (US$86.30 vs US$12.88], per patient over 6 months. The costs with medications in the last month for patients with mild, moderate and severe asthma were US$1.60, 9.60, and 25.00 in the uncontrolled patients, respectively, and US$6.50, 19.00 and 49.00 in the controlled patients. In view of the small proportion of uncontrolled subjects receiving regular maintenance medication (22.2% and their lack of resources, providing free medication for uncontrolled patients might be a cost-effective strategy for the public health system.

  14. A direct comparison of local dynamic stability during unperturbed standing and walking.

    Science.gov (United States)

    Kang, Hyun Gu; Dingwell, Jonathan B

    2006-06-01

    Standing and walking are very different tasks. It might be reasonable, therefore, to assume that the mechanisms used to maintain the stability of standing and walking should be quite different. However, many studies have shown that postural stability measures can generally predict risk of falls, even though most falls occur during locomotor tasks and not during postural tasks. This suggests that there is at least some commonality among the mechanisms governing the control of both standing and walking. The present study was conducted to determine whether the postural stability either is or is not directly related to locomotor stability. Twenty healthy adults, age 18-73 years, walked on a motorized treadmill at their preferred walking speed for three trials of 5 min. They also stood on a force plate for three trials of 5 min. Both tasks were performed without imposing any additional external perturbations. The motion of each subject's trunk segment was recorded and described using a multi-dimensional state space defined in the same manner for both tasks. Local dynamic stability was quantified from the mean divergence over time of locally perturbed trajectories in state space, which was parameterized as a double exponential process. Divergence parameters were compared to determine the relationship between local dynamic stability during standing and walking. Standing and walking exhibited local dynamic stability properties that were significantly different (P0.1). Divergence parameters were also compared to traditional center of pressure (COP) measures obtained from standing trials. COP measures were significantly correlated to local divergence parameters for standing, but not to those for walking. This study provides direct evidence that the mechanisms governing standing and walking stability are significantly different.

  15. Direct Interconversion of BINOL and H8-BINOL-Based Chiral Brønsted Acids Using Single-Step Red/Ox Manipulations.

    Science.gov (United States)

    Tay, Jia-Hui; Arguelles, Alonso J; Nagorny, Pavel

    2015-08-07

    A direct single-step hydrogenation of BINOL-based chiral phosphoric acids, N-triflyl phosphoramides, and disulfonimides to the corresponding H8-BINOL Brønsted acids in excellent yields and chemoselectivities is described. In addition, the conditions for the single-step oxidation of H8-BINOL-based Brønsted acids into the corresponding BINOL-based acids have been identified and employed to accomplish these interconversions in 41-81% yield.

  16. FIRE DESIGN: DIRECT COMPARISON BETWEEN FIRE CURVES. THE CASE STUDY OF A NURSERY

    Directory of Open Access Journals (Sweden)

    Mara Lombardi

    2013-01-01

    Full Text Available According to fire safety engineering, the present study analyzes fire design settings for simulation of fire in a nursery and proposes to compare simulations developed with a natural fire curve and nominal fire curve. Comparative analysis was developed according to thermo-fluid dynamic parameters that are relevant to the safety of the exposed and for the representative period of the danger flow to the exposed, which are mainly children between 0 and 3 years of age, helpless under ordinary conditions and even more so in case of emergency. Defined conditions of structure and ventilation, Two fire simulations, differentiated by fire curve, have been implemented: First simulation: the parameters have been derived from the simulation of a fire, characterized by analytic function of Heat Release Rate (HRR Second simulation: the HRR function was obtained ex post by making a simulation of natural fire in realistically furnished room by imposing a minimum effective primer. The simulated HRR curve, appropriately linearized, allows to estimate a Likely Fire Curve (LFC. The simulations have been developed for a time of about 15 min, starting from the ignition of fire whereas the flow of the danger is serious for exposed mainly in this first phase of fire. The comparison between the parameters of fire involved the Temperature-Time Curve and HRR-Time Curve of both simulations and the ISO 834 Curve, which is a consolidated benchmark in Fire Safety Engineering (FSE. The nominal curves have been introduced for the purpose of checking whether the structural strength and integrity: the adoption of these curves in the fire safety engineering was made by analogy, on the assumption that the phenomena of major intensity, that these curves represent, ensure a safe approach on the choice of the fire design. The study showed indeed that the analytical curve, adopted in order to verify the structural strength, produces fields of both temperature and toxic concentrations

  17. Lead-acid traction batteries for electric road vehicle propulsion Directions for research and development

    Science.gov (United States)

    Rand, D. A. J.

    1980-09-01

    Little information exists on the behavior of lead-acid batteries operating under the duty cycles normal to electric road vehicle service. Important battery requirements for the propulsion of traffic-compatible electric vehicles include a deep-discharge capability at high efficiencies of active material utilization, and a long cycle life. In order to optimize power-source characteristics to meet these criteria, especially for passenger cars, it is necessary to gain full knowledge of the influence of actual vehicle service on the performance of traction batteries. This article defines areas in which both fundamental and applied work are required to achieve this aim based on the current performance of the lead-acid system.

  18. Comparison of Hensen's node and retinoic acid in secondary axis induction in the early chick embryo.

    Science.gov (United States)

    Chen, Y; Solursh, M

    1992-10-01

    Retinoic acid (RA) and Hensen's node, the organizer center in the chick embryo, have been shown to have polarizing activity when applied or grafted into the chick limb bud. Here we investigate and compare the effects of RA and grafted Hensen's node on the early chick embryo. Anion exchange beads soaked with RA at concentrations ranging from 5 to 100 ng/ml and implanted on the anterior side or on the left side of the host anteroposterior axis of a stage 4 chick embryo in ovo have the ability to induce secondary axis formation, while beads soaked with RA of the same concentration and implanted on the right side or on the posterior side of the host axis are unable to induce the secondary axis. All of the induced axes contain trunk-tail structures. Hensen's node from quail embryos implanted into the early chick blastoderm could also cause the formation of secondary axes in addition to self-differentiation of the graft into a secondary axis. Both RA and grafted Hensen's node caused the inhibition of forebrain development with an increase in hindbrain development and the host heart to loop in an abnormal direction. The results support the hypothesis that Hensen's node is a source of RA which is involved in early embryogenesis. Alternatively, RA might stimulate the formation of Hensen's nodal properties in adjacent tissue.

  19. Heterogeneous and homogeneous catalysis for the hydrogenation of carboxylic acid derivatives: history, advances and future directions.

    Science.gov (United States)

    Pritchard, James; Filonenko, Georgy A; van Putten, Robbert; Hensen, Emiel J M; Pidko, Evgeny A

    2015-06-01

    The catalytic reduction of carboxylic acid derivatives has witnessed a rapid development in recent years. These reactions, involving molecular hydrogen as the reducing agent, can be promoted by heterogeneous and homogeneous catalysts. The milestone achievements and recent results by both approaches are discussed in this Review. In particular, we focus on the mechanistic aspects of the catalytic hydrogenation and highlight the bifunctional nature of the mechanism that is preferred for supported metal catalysts as well as homogeneous transition metal complexes.

  20. Food Additives Permitted for Direct Addition to Food for Human Consumption; Folic Acid. Final rule.

    Science.gov (United States)

    2016-04-15

    The Food and Drug Administration (FDA or we) is amending the food additive regulations to provide for the safe use of folic acid in corn masa flour. We are taking this action in response to a food additive petition filed jointly by Gruma Corporation, Spina Bifida Association, March of Dimes Foundation, American Academy of Pediatrics, Royal DSM N.V., and National Council of La Raza.

  1. Direct monophasic replacement of fatty acid by DMSA on SPION surface

    Science.gov (United States)

    Gogoi, M.; Deb, P.; Vasan, G.; Keil, P.; Kostka, A.; Erbe, A.

    2012-10-01

    Tailoring the surface and understanding the surface characteristics is necessary for biomedical applications of superparamagnetic nanoparticles. In this paper, superparamagnetic iron oxide nanoparticles (SPIONs) were prepared by thermal decomposition of iron nitrate in presence of stearic acid as surfactant. Due to the multilayer organization of surfactant molecules over the nanoparticle surface, the surface potential can be tuned by pH changes and hence the nanoparticles can be made dispersible in nonpolar as well as in polar solvents. We have presented a simple, facile procedure for controlled replacement of stearic acid from maghemite surface and subsequent derivatization by biocompatible dimercaptosuccinic acid (DMSA) to obtain ultrastable hydrophilic nanoparticles with unaltered morphology, phase and properties. The surface chemistry of the functionalized SPIONs was analyzed by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS) revealing the presence of bound and unbound thiol groups and disulfides, leading to its prolonged stability in aqueous medium. The consequence of spatially selective functionalization on the stability and solubility of surface hydrophilic SPION has also been realized.

  2. Comparison of amino acid derivatization reagents for LC-ESI-MS analysis. Introducing a novel phosphazene-based derivatization reagent.

    Science.gov (United States)

    Rebane, Riin; Oldekop, Maarja-Liisa; Herodes, Koit

    2012-09-01

    Amino acid analysis with high performance liquid chromatography with electrospray ionization mass spectrometry (LC-ESI-MS) is an emerging method. For more sensitive analysis, derivatization is used and next to commercially available derivatization reagents such as dansyl chloride (DNS), 9-fluorenylmethyl chloroformate (FMOC-Cl) and diethyl ethoxymethylenemalonate (DEEMM), new derivatization reagents are designed specially for LC-ESI-MS, like p-N,N,N-trimethylammonioanilyl N'-hydroxysuccinimidyl carbamate iodide (TAHS) which provides very low limits of detection. In this work, a novel phosphazene based derivatization reagent (FOSF) that provides comparable limits of quantitation (LoQ) to TAHS is introduced. Moreover, a thorough comparison between FOSF, TAHS, DNS, FMOC-Cl and DEEMM is carried out for 7 different amino acids - Arg, Asp, Gly, β-Ala, Pro, Trp and Phe. This is a first time that thorough comparison is carried out on the same instrument for amino acid derivatization reagents. Results on the same instrument for five amino acid derivatization reagents show that novel reagents are sensitive with LoQ values around 80 fmol but have disadvantages such as problematic chromatographic separation. Next to novel reagents, DEEMM offers very good LoQ-s (average of 150 fmol) and wide dynamic linear range.

  3. Economic feasibility study of biodiesel production by direct esterification of fatty acids from the oil and soap industrial sector

    Directory of Open Access Journals (Sweden)

    M.I. El-Galad

    2015-12-01

    Full Text Available Industrial production of biodiesel fuel in Egypt by the transesterification of vegetable oils is being faced with the problem of feedstock shortage. Egypt imports annually about 90% of its needs as edible oils for human consumption. The production of biodiesel by direct esterification of fatty acids that can be obtained from the oil and soap industrial sector in huge quantities each year (around 16 thousand tons may be a proper solution to this problem. According to results of a previous study [1], the biodiesel produced following this approach and using methyl alcohol was quite efficient as an alternative fuel for diesel engines. However, the process should be economically feasible for application on an industrial scale. The present study assessed the economic feasibility of biodiesel production by direct fatty acid esterification. Complete process simulation was first carried out using the process simulation software, Aspen HYSYS V7.0. The process was then designed comprising four main steps being esterification, solvent recovery, catalyst removal and water removal. The main processing units include the reactor, distillation column, heat exchangers, pumps and separators. Assuming that the rate of fatty acids esterified was 2 ton/h, all process units required have been sized. Total capital investment, total manufacturing cost and return on investment were all estimated. The latter was found to be 117.1% which means that the production process is quite economically feasible.

  4. Comparison of Butyric acid concentrations in ordinary and probiotic yogurt samples in Iran

    OpenAIRE

    Narges Vaseji; Naheed Mojgani; Cyrus Amirinia; Iranmanesh, M

    2012-01-01

    Background and objectives: Butyric acid has many applications in chemical, food and pharmaceutical industries. Applications of butyric acid are as an additive to food, flavorings, varnishes, perfumes, pharmaceuticals and disinfectants. Butyric acid concentrations have positive impact on the quality control of milk, yogurt and other probiotic dairy products. The present investigation was undertaken to determine and compare the concentrations of butyric acid (C4) in the ordinary and probiotic y...

  5. A Comparison of Direct and Two-Stage Transportation of Patients to Hospital in Poland

    Directory of Open Access Journals (Sweden)

    Anna Rosiek

    2015-04-01

    Full Text Available Background: The rapid international expansion of telemedicine reflects the growth of technological innovations. This technological advancement is transforming the way in which patients can receive health care. Materials and Methods: The study was conducted in Poland, at the Department of Cardiology of the Regional Hospital of Louis Rydygier in Torun. The researchers analyzed the delay in the treatment of patients with acute coronary syndrome. The study was conducted as a survey and examined 67 consecutively admitted patients treated invasively in a two-stage transport system. Data were analyzed statistically. Results: Two-stage transportation does not meet the timeframe guidelines for the treatment of patients with acute myocardial infarction. Intervals for the analyzed group of patients were statistically significant (p < 0.0001. Conclusions: Direct transportation of the patient to a reference center with interventional cardiology laboratory has a significant impact on reducing in-hospital delay in case of patients with acute coronary syndrome. Perspectives: This article presents the results of two-stage transportation of the patient with acute coronary syndrome. This measure could help clinicians who seek to assess time needed for intervention. It also shows how time from the beginning of pain in chest is important and may contribute to patient disability, death or well-being.

  6. Comparison of the diagnostic accuracy of direct digital radiography system, filtered images, and subtraction radiography

    Directory of Open Access Journals (Sweden)

    Wilton Mitsunari Takeshita

    2013-01-01

    Full Text Available Background: To compare the diagnostic accuracy of three different imaging systems: Direct digital radiography system (DDR-CMOS, four types of filtered images, and a priori and a posteriori registration of digital subtraction radiography (DSR in the diagnosis of proximal defects. Materials and Methods: The teeth were arranged in pairs in 10 blocks of vinyl polysiloxane, and proximal defects were performed with drills of 0.25, 0.5, and 1 mm diameter. Kodak RVG 6100 sensor was used to capture the images. A posteriori DSR registrations were done with Regeemy 0.2.43 and subtraction with Image Tool 3.0. Filtered images were obtained with Kodak Dental Imaging 6.1 software. Images (n = 360 were evaluated by three raters, all experts in dental radiology. Results: Sensitivity and specificity of the area under the receiver operator characteristic (ROC curve (Az were higher for DSR images with all three drills (Az = 0.896, 0.979, and 1.000 for drills 0.25, 0.5, and 1 mm, respectively. The highest values were found for 1-mm drills and the lowest for 0.25-mm drills, with negative filter having the lowest values of all (Az = 0.631. Conclusion: The best method of diagnosis was by using a DSR. The negative filter obtained the worst results. Larger drills showed the highest sensitivity and specificity values of the area under the ROC curve.

  7. Gaussian variational ansatz in the problem of anomalous sea waves: Comparison with direct numerical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Ruban, V. P., E-mail: ruban@itp.ac.ru [Russian Academy of Sciences, Landau Institute for Theoretical Physics (Russian Federation)

    2015-05-15

    The nonlinear dynamics of an obliquely oriented wave packet on a sea surface is analyzed analytically and numerically for various initial parameters of the packet in relation to the problem of the so-called rogue waves. Within the Gaussian variational ansatz applied to the corresponding (1+2)-dimensional hyperbolic nonlinear Schrödinger equation (NLSE), a simplified Lagrangian system of differential equations is derived that describes the evolution of the coefficients of the real and imaginary quadratic forms appearing in the Gaussian. This model provides a semi-quantitative description of the process of nonlinear spatiotemporal focusing, which is one of the most probable mechanisms of rogue wave formation in random wave fields. The system of equations is integrated in quadratures, which allows one to better understand the qualitative differences between linear and nonlinear focusing regimes of a wave packet. Predictions of the Gaussian model are compared with the results of direct numerical simulation of fully nonlinear long-crested waves.

  8. Direct chloroplast sequencing: comparison of sequencing platforms and analysis tools for whole chloroplast barcoding.

    Directory of Open Access Journals (Sweden)

    Marta Brozynska

    Full Text Available Direct sequencing of total plant DNA using next generation sequencing technologies generates a whole chloroplast genome sequence that has the potential to provide a barcode for use in plant and food identification. Advances in DNA sequencing platforms may make this an attractive approach for routine plant identification. The HiSeq (Illumina and Ion Torrent (Life Technology sequencing platforms were used to sequence total DNA from rice to identify polymorphisms in the whole chloroplast genome sequence of a wild rice plant relative to cultivated rice (cv. Nipponbare. Consensus chloroplast sequences were produced by mapping sequence reads to the reference rice chloroplast genome or by de novo assembly and mapping of the resulting contigs to the reference sequence. A total of 122 polymorphisms (SNPs and indels between the wild and cultivated rice chloroplasts were predicted by these different sequencing and analysis methods. Of these, a total of 102 polymorphisms including 90 SNPs were predicted by both platforms. Indels were more variable with different sequencing methods, with almost all discrepancies found in homopolymers. The Ion Torrent platform gave no apparent false SNP but was less reliable for indels. The methods should be suitable for routine barcoding using appropriate combinations of sequencing platform and data analysis.

  9. GPS scintillation effects associated with polar cap patches and substorm auroral activity: direct comparison

    Directory of Open Access Journals (Sweden)

    Jin Yaqi

    2014-01-01

    Full Text Available We directly compare the relative GPS scintillation levels associated with regions of enhanced plasma irregularities called auroral arcs, polar cap patches, and auroral blobs that frequently occur in the polar ionosphere. On January 13, 2013 from Ny-Ålesund, several polar cap patches were observed to exit the polar cap into the auroral oval, and were then termed auroral blobs. This gave us an unprecedented opportunity to compare the relative scintillation levels associated with these three phenomena. The blobs were associated with the strongest phase scintillation (σϕ, followed by patches and arcs, with σϕ up to 0.6, 0.5, and 0.1 rad, respectively. Our observations indicate that most patches in the nightside polar cap have produced significant scintillations, but not all of them. Since the blobs are formed after patches merged into auroral regions, in space weather predictions of GPS scintillations, it will be important to enable predictions of patches exiting the polar cap.

  10. Comparison of advection and steam fogs: From direct observation over the sea

    Science.gov (United States)

    Heo, Ki-Young; Ha, Kyung-Ja; Mahrt, Larry; Shim, Jae-Seol

    2010-11-01

    Sea fog occurs frequently over the Yellow Sea in spring and summer, which causes costly or even catastrophic events including property damage, marine accidents, public health and financial losses. Case studies of advection and steam fogs using direct observation over the sea are constructed to better understand their formation, evolution and dissipation. A southerly wind supplies moisture to initiate advection fog events (AFs). Approximately -100 to -200 W m-2 of latent heat flux and -70 W m-2 of sensible heat flux during mature AFs are characterized with stable stratification which maintains dense fog by limiting downward mixing of dryer air. Steam fogs (SFs) develop from flow of cold air over warmer water, but are normally of limited persistence. During the SFs, a northerly wind decreases the air temperature below the sea surface temperature, which increases the relative humidity through evaporation from the warmer ocean. During mature SF, 360 W m-2 of latent heat flux and 150 W m-2 of sensible heat flux are characterized with neutral and unstable atmospheric conditions. The increase in wind speed and wind shear mixes dry air downward to the surface and limits the duration of the SF.

  11. Comparison of direct measurement methods for headset noise exposure in the workplace

    Directory of Open Access Journals (Sweden)

    Flora G Nassrallah

    2016-01-01

    Full Text Available The measurement of noise exposure from communication headsets poses a methodological challenge. Although several standards describe methods for general noise measurements in occupational settings, these are not directly applicable to noise assessments under communication headsets. For measurements under occluded ears, specialized methods have been specified by the International Standards Organization (ISO 11904 such as the microphone in a real ear and manikin techniques. Simpler methods have also been proposed in some national standards such as the use of general purpose artificial ears and simulators in conjunction with single number corrections to convert measurements to the equivalent diffuse field. However, little is known about the measurement agreement between these various methods and the acoustic manikin technique. Twelve experts positioned circum-aural, supra-aural and insert communication headsets on four different measurement setups (Type 1, Type 2, Type 3.3 artificial ears, and acoustic manikin. Fit-refit measurements of four audio communication signals were taken under quiet laboratory conditions. Data were transformed into equivalent diffuse-field sound levels using third-octave procedures. Results indicate that the Type 1 artificial ear is not suited for the measurement of sound exposure under communication headsets, while Type 2 and Type 3.3 artificial ears are in good agreement with the acoustic manikin technique. Single number corrections were found to introduce a large measurement uncertainty, making the use of the third-octave transformation preferable.

  12. Comparison of directed and weighted co-occurrence networks of six languages

    Science.gov (United States)

    Gao, Yuyang; Liang, Wei; Shi, Yuming; Huang, Qiuling

    2014-01-01

    To study commonalities and differences among different languages, we select 100 reports from the documents of the United Nations, each of which was written in Arabic, Chinese, English, French, Russian and Spanish languages, separately. Based on these corpora, we construct 6 weighted and directed word co-occurrence networks. Besides all the networks exhibit scale-free and small-world features, we find several new non-trivial results, including connections among English words are denser, and the expression of English language is more flexible and powerful; the connection way among Spanish words is more stringent and this indicates that the Spanish grammar is more rigorous; values of many statistical parameters of the French and Spanish networks are very approximate and this shows that these two languages share many commonalities; Arabic and Russian words have many varieties, which result in rich types of words and a sparse connection among words; connections among Chinese words obey a more uniform distribution, and one inclines to use the least number of Chinese words to express the same complex information as those in other five languages. This shows that the expression of Chinese language is quite concise. In addition, several topics worth further investigating by the complex network approach have been observed in this study.

  13. Direct numerical simulation of pore-scale flow in a bead pack: Comparison with magnetic resonance imaging observations

    Science.gov (United States)

    Yang, Xiaofan; Scheibe, Timothy D.; Richmond, Marshall C.; Perkins, William A.; Vogt, Sarah J.; Codd, Sarah L.; Seymour, Joseph D.; McKinley, Matthew I.

    2013-04-01

    A significant body of current research is aimed at developing methods for numerical simulation of flow and transport in porous media that explicitly resolve complex pore and solid geometries, and at utilizing such models to study the relationships between fundamental pore-scale processes and macroscopic manifestations at larger (i.e., Darcy) scales. A number of different numerical methods for pore-scale simulation have been developed, and have been extensively tested and validated for simplified geometries. However, validation of pore-scale simulations of fluid velocity for complex, three-dimensional (3D) pore geometries that are representative of natural porous media is challenging due to our limited ability to measure pore-scale velocity in such systems. Recent advances in magnetic resonance imaging (MRI) offer the opportunity to measure not only the pore geometry, but also local fluid velocities under steady-state flow conditions in 3D and with high spatial resolution. In this paper, we present a 3D velocity field measured at sub-pore resolution (tens of micrometers) over a centimeter-scale 3D domain using MRI methods. We have utilized the measured pore geometry to perform 3D simulations of Navier-Stokes flow over the same domain using direct numerical simulation techniques. We present a comparison of the numerical simulation results with the measured velocity field. It is shown that the numerical results match the observed velocity patterns well overall except for a variance and small systematic scaling which can be attributed to the known experimental uncertainty in the MRI measurements. The comparisons presented here provide strong validation of the pore-scale simulation methods and new insights for interpretation of uncertainty in MRI measurements of pore-scale velocity. This study also provides a potential benchmark for future comparison of other pore-scale simulation methods. 2012 Elsevier Science.

  14. Sub-ns time transfer consistency: a direct comparison between GPS CV and T2L2

    Science.gov (United States)

    Exertier, P.; Samain, E.; Courde, C.; Aimar, M.; Torre, J. M.; Rovera, G. D.; Abgrall, M.; Uhrich, P.; Sherwood, R.; Herold, G.; Schreiber, U.; Guillemot, P.

    2016-12-01

    This paper presents a direct comparison between two satellite time transfer techniques: common-view (CV) of satellites from the global positioning system (GPS) constellation, and time transfer by laser link (T2L2) through the low orbiting satellite Jason-2. We describe briefly both techniques, together with two independent relative calibration campaigns of the links involving four European laboratories. Between the same remote time scale reference points, the mean values of the calibrated differences between GPS CV and T2L2 are below 240 ps, with standard deviations below 500 ps, mostly due to GPS CV. Almost all sample deviations from 0 ns are within the combined uncertainty estimates. Despite the relatively small number of common points obtained, due to the fact that T2L2 is weather dependent, these results provide an unprecedented sub-ns consistency between two independently calibrated microwave and optical satellite time transfer techniques.

  15. A direct comparison between two independently calibrated time transfer techniques: T2L2 and GPS Common-Views

    Science.gov (United States)

    Rovera, G. D.; Abgrall, M.; Courde, C.; Exertier, P.; Fridelance, P.; Guillemot, Ph; Laas-Bourez, M.; Martin, N.; Samain, E.; Sherwood, R.; Torre, J.-M.; Uhrich, P.

    2016-06-01

    We present a direct comparison between two satellite time transfer techniques on independently calibrated links: Time Transfer by Laser Link (T2L2) and Common-Views (CV) of satellites from the Global Positioning System (GPS) constellation. The GPS CV and T2L2 links between three European laboratories where independently calibrated against the same reference point of the local timescales. For all the links the mean values of the differences between GPS CV and T2L2 are equal or below 240 ps, with standard deviations below 500 ps, mostly due to GPS CV. Almost all deviations from 0 ns are within the combined uncertainty estimates. Despite the weak number of common points obtained, due to the fact that T2L2 is weather dependent, these results are providing an unprecedented sub-ns consistency between two independently calibrated microwave and optical satellite time transfer techniques.

  16. Distribution of salicylic acid in human stratum corneum following topical application in vivo: a comparison of six different formulations.

    Science.gov (United States)

    Tsai, J; Chuang, S; Hsu, M; Sheu, H

    1999-10-25

    Distribution of salicylic acid in human stratum corneum from treatment of six different formulations was assessed by quantitation of drug content in sequentially tape-stripped stratum corneum after a single 2-h dose was applied unoccluded to skin on the ventral forearm of four female subjects. The profile and total amounts of stratum corneum removed in 20 tape-strips varied among different types of formulations. With or without normalization by the total stratum corneum weights removed, the extent of drug delivery to the stratum corneum decreased in the following order: SA (5%) > > SAC (10%), Duofilm (16.7%) > TSSS (2%) > SAO (10%), Salic (2.5%), the percentage in parentheses indicating the salicylic acid concentration in each formulation. The greatest topical bioavailability was observed for the alcoholic solution containing glycerol (SA). The 10% collodion formulation (SAC) was found to deliver an amount of salicylic acid into the stratum corneum 2-fold greater than 10% ointment formulation (SAO). Use of absorption ointment (TSSS) also increased the uptake of salicylic acid into the stratum corneum in comparison with formulations based on simple ointment (SAO) and oil in water (o/w) cream (Salic). The partitioning of salicylic acid from collodion formulations (SAC and Duofilm) appeared to be concentration-independent. The results of this study indicate that topical bioavailability of salicylic acid in the stratum corneum varies substantially among different formulations.

  17. The proteolytic system of lactic acid bacteria revisited : a genomic comparison

    NARCIS (Netherlands)

    Liu, M.; Bayjanov, J.; Renckens, B.A.M.; Nauta, A.; Siezen, R.J.

    2010-01-01

    BACKGROUND: Lactic acid bacteria (LAB) are a group of gram-positive, lactic acid producing Firmicutes. They have been extensively used in food fermentations, including the production of various dairy products. The proteolytic system of LAB converts proteins to peptides and then to amino acids, which

  18. Comparison of Bile Acids and Acetaminophen Protein Adducts in Children and Adolescents with Acetaminophen Toxicity.

    Science.gov (United States)

    James, Laura; Yan, Ke; Pence, Lisa; Simpson, Pippa; Bhattacharyya, Sudeepa; Gill, Pritmohinder; Letzig, Lynda; Kearns, Gregory; Beger, Richard

    2015-01-01

    Metabolomics approaches have enabled the study of new mechanisms of liver injury in experimental models of drug toxicity. Disruption of bile acid homeostasis is a known mechanism of drug induced liver injury. The relationship of individual bile acids to indicators of oxidative drug metabolism (acetaminophen protein adducts) and liver injury was examined in children with acetaminophen overdose, hospitalized children with low dose exposure to acetaminophen, and children with no recent exposure to acetaminophen. Nine bile acids were quantified through targeted metabolomic analysis in the serum samples of the three groups. Bile acids were compared to serum levels of acetaminophen protein adducts and alanine aminotransferase. Glycodeoxycholic acid, taurodeoxycholic acid, and glycochenodeoxycholic acid were significantly increased in children with acetaminophen overdose compared to healthy controls. Among patients with acetaminophen overdose, bile acids were higher in subjects with acetaminophen protein adduct values > 1.0 nmol/mL and modest correlations were noted for three bile acids and acetaminophen protein adducts as follows: taurodeoxycholic acid (R=0.604; pacetaminophen than in healthy children with no recent acetaminophen exposure. Compared to bile acids, acetaminophen protein adducts more accurately discriminated among children with acetaminophen overdose, children with low dose exposure to acetaminophen, and healthy control subjects. In children with acetaminophen overdose, elevations of conjugated bile acids were associated with specific indicators of acetaminophen metabolism and non-specific indicators of liver injury.

  19. The Energy Spectrum of Telescope Array's Middle Drum Detector and the Direct Comparison to the High Resolution Fly's Eye Experiment

    CERN Document Server

    Abu-Zayyad, T; Allen, M; Anderson, R; Azuma, R; Barcikowski, E; Belz, J W; Bergman, D R; Blake, S A; Cady, R; Cheon, B G; Chiba, J; Chikawa, M; Cho, E J; Cho, W R; Fujii, H; Fujii, T; Fukuda, T; Fukushima, M; Gorbunov, D; Hanlon, W; Hayashi, K; Hayashi, Y; Hayashida, N; Hibino, K; Hiyama, K; Honda, K; Iguchi, T; Ikeda, D; Ikuta, K; Inoue, N; Ishii, T; Ishimori, R; Ivanov, D; Iwamoto, S; Jui, C C H; Kadota, K; Kakimoto, F; Kalashev, O; Kanbe, T; Kasahara, K; Kawai, H; Kawakami, S; Kawana, S; Kido, E; Kim, H B; Kim, H K; Kim, J H; Kim, J H; Kitamoto, K; Kitamura, S; Kitamura, Y; Kobayashi, K; Kobayashi, Y; Kondo, Y; Kuramoto, K; Kuzmin, V; Kwon, Y J; Lim, S I; Machida, S; Martens, K; Martineau, J; Matsuda, T; Matsuura, T; Matsuyama, T; Matthews, J N; Minamino, M; Miyata, K; Murano, Y; Nagataki, S; Nakamura, T; Nam, S W; Nonaka, T; Ogio, S; Ohnishi, M; Ohoka, H; Oki, K; Oku, D; Okuda, T; Oshima, A; Ozawa, S; Park, I H; Pshirkov, M S; Rodriguez, D C; Roh, S Y; Rubtsov, G; Ryu, D; Sagawa, H; Sakurai, N; Sampson, A L; Scott, L M; Shah, P D; Shibata, F; Shibata, T; Shimodaira, H; Shin, B K; Shin, J I; Shirahama, T; Smith, J D; Sokolsky, P; Sonley, T J; Springer, R W; Stokes, B T; Stratton, S R; Stroman, T; Suzuki, S; Takahashi, Y; Takeda, M; Taketa, A; Takita, M; Tameda, Y; Tanaka, H; Tanaka, K; Tanaka, M; Thomas, S B; Thomson, G B; Tinyakov, P; Tkachev, I; Tokuno, H; Tomida, T; Troitsky, S; Tsunesada, Y; Tsutsumi, K; Tsuyuguchi, Y; Uchihori, Y; Udo, S; Ukai, H; Vasiloff, G; Wada, Y; Wong, T; Wood, M; Yamakawa, Y; Yamane, R; Yamaoka, H; Yamazaki, K; Yang, J; Yoneda, Y; Yoshida, S; Yoshii, H; Zollinger, R; Zundel, Z

    2012-01-01

    The Telescope Array's Middle Drum fluorescence detector was instrumented with telescopes refurbished from the High Resolution Fly's Eye's HiRes-1 site. The data observed by Middle Drum in monocular mode was analyzed via the HiRes-1 profile-constrained geometry reconstruction technique and utilized the same calibration techniques enabling a direct comparison of the energy spectra and energy scales between the two experiments. The spectrum measured using the Middle Drum telescopes is based on a three-year exposure collected between December 16, 2007 and December 16, 2010. The calculated difference between the spectrum of the Middle Drum observations and the published spectrum obtained by the data collected by the HiRes-1 site allows the HiRes-1 energy scale to be transferred to Middle Drum. The HiRes energy scale is applied to the entire Telescope Array by making a comparison between Middle Drum monocular events and hybrid events that triggered both Middle Drum and the Telescope Array's scintillator Ground Arra...

  20. Direct Numerical Simulation of Fracture Behaviour for Random Short Wood Fibres Reinforced Composites, Comparison with Digital Image Correlation Experiments

    Science.gov (United States)

    Shen, M.; Touchard, F.; Bezine, G.; Brillaud, J.

    2010-06-01

    The work is to predict fracture behaviour of bio-composites from the tensile properties of its components. In this work, we have realized a direct numerical simulation of fracture behaviour for random short spruce fibers reinforced composites. For calculations, wood fibers have been considered as linear elastic bodies, polypropylene matrix as an elastic-plastic material. Then, numerical results have been compared with experimental results that have been obtained by digital image correlation. This comparison indicates that random fiber FE model of random short spruce fibers reinforced composites can be able to fairly reflect the influence of random fibers microstructure in the composite on its fracture behavior. The calculation of both random fiber and homogeneous FE model and their comparison with experiments show that the average values of J-integral in a region in the front of the crack tip from both numerical FE models are in good agreement with the average J value of DIC experiment in the same region when the numerical and experimental CT specimens of the short spruce fiber reinforced composite are subjected to the same extension at their loading point.

  1. Direct Numerical Simulation of Fracture Behaviour for Random Short Wood Fibres Reinforced Composites, Comparison with Digital Image Correlation Experiments

    Directory of Open Access Journals (Sweden)

    Brillaud J.

    2010-06-01

    Full Text Available The work is to predict fracture behaviour of bio-composites from the tensile properties of its components. In this work, we have realized a direct numerical simulation of fracture behaviour for random short spruce fibers reinforced composites. For calculations, wood fibers have been considered as linear elastic bodies, polypropylene matrix as an elastic-plastic material. Then, numerical results have been compared with experimental results that have been obtained by digital image correlation. This comparison indicates that random fiber FE model of random short spruce fibers reinforced composites can be able to fairly reflect the influence of random fibers microstructure in the composite on its fracture behavior. The calculation of both random fiber and homogeneous FE model and their comparison with experiments show that the average values of J-integral in a region in the front of the crack tip from both numerical FE models are in good agreement with the average J value of DIC experiment in the same region when the numerical and experimental CT specimens of the short spruce fiber reinforced composite are subjected to the same extension at their loading point.

  2. Quantitative Determination and Comparison of the Surface Binding of Phosphonic Acid, Carboxylic Acid, and Catechol Ligands on TiO2 Nanoparticles.

    Science.gov (United States)

    Zeininger, Lukas; Portilla, Luis; Halik, Marcus; Hirsch, Andreas

    2016-09-12

    The adsorption, desorption, co-adsorption, and exchange behavior of phosphonic acid, carboxylic acid, and catechol derivatives on the surface of titanium oxide (anatase) nanoparticles are investigated. Thermogravimetric analysis provides a facile and fast-track quantitative determination of the wet-chemical monolayer adsorption constants and grafting densities of ten adsorbates, all under neutral pH conditions. This characterization protocol allows straightforward quantification of the relevant thermodynamic data of ligand adsorption and a comparison of ligand adsorption strengths. The reported procedure is proposed as a universal tool and it should be applicable to many other colloidal metal oxide materials. Moreover, the determined values for the adsorption constants and the monolayer grafting densities provide a toolbox for the assessment of the adsorbates' behavior in desorption, exchange, and co-adsorption equilibria. This versatile evaluation procedure will help to identify optimal monolayer-surface combinations and to evaluate critical parameters, such as monolayer robustness, ligand exchange rates, or targeted mixed assembly of functionalities.

  3. Direct electrodeposition of gold nanotube arrays of rough and porous wall by cyclic voltammetry and its applications of simultaneous determination of ascorbic acid and uric acid.

    Science.gov (United States)

    Yang, Guangming; Li, Ling; Jiang, Jinhe; Yang, Yunhui

    2012-08-01

    Gold nanotube arrays of rough and porous wall has been synthesized by direct electrodeposition with cyclic voltammetry utilizing anodic aluminum oxide template (AAO) and polycarbonate membrane (PC) during short time (only 3 min and 2 min, respectively). The mechanism of the direct electrodeposition of gold nanotube arrays by cyclic voltammetry (CV) has been discussed. The morphological characterizations of the gold nanotube arrays have been investigated by scanning electron microscopy (SEM). A simultaneous determination of ascorbic acid (AA) and uric acid (UA) by differential pulse voltammetry (DPV) was constructed by attaching gold nanotube arrays (using AAO) onto the surface of a glassy carbon electrode (GCE). The electrochemical behavior of AA and UA at this modified electrode has been studied by CV and differential pulse voltammetry (DPV). The sensor offers an excellent response for AA and UA and the linear response range for AA and UA were 1.02×10(-7)-5.23×10(-4) mol L(-1) and 1.43×10(-7)-4.64×10(-4) mol L(-1), the detection limits were 1.12×10(-8) mol L(-1) and 2.24×10(-8) mol L(-1), respectively. This sensor shows good regeneration, stability and selectivity and has been used for the determination of AA and UA in real human urine and serum samples with satisfied results.

  4. Direct Determination of a Small-Molecule Drug, Valproic Acid, by an Electrically-Detected Microcantilever Biosensor for Personalized Diagnostics

    Directory of Open Access Journals (Sweden)

    Long-Sun Huang

    2015-01-01

    Full Text Available Direct, small-molecule determination of the antiepileptic drug, valproic acid, was investigated by a label-free, nanomechanical biosensor. Valproic acid has long been used as an antiepileptic medication, which is administered through therapeutic drug monitoring and has a narrow therapeutic dosage range of 50–100 μg·mL−1 in blood or serum. Unlike labeled and clinically-used measurement techniques, the label-free, electrical detection microcantilever biosensor can be miniaturized and simplified for use in portable or hand-held point-of-care platforms or personal diagnostic tools. A micromachined microcantilever sensor was packaged into the micro-channel of a fluidic system. The measurement of the antiepileptic drug, valproic acid, in phosphate-buffered saline and serum used a single free-standing, piezoresistive microcantilever biosensor in a thermally-controlled system. The measured surface stresses showed a profile over a concentration range of 50–500 μg·mL−1, which covered the clinically therapeutic range of 50–100 μg·mL−1. The estimated limit of detection (LOD was calculated to be 45 μg·mL−1, and the binding affinity between the drug and the antibody was measured at around 90 ± 21 μg·mL−1. Lastly, the results of the proposed device showed a similar profile in valproic acid drug detection with those of the clinically-used fluorescence polarization immunoassay.

  5. Comparisons of treatment optimization directly incorporating random patient setup uncertainty with a margin-based approach.

    Science.gov (United States)

    Moore, Joseph A; Gordon, John J; Anscher, Mitchell S; Siebers, Jeffrey V

    2009-09-01

    The purpose of this study is to incorporate the dosimetric effect of random patient positioning uncertainties directly into a commercial treatment planning system's IMRT plan optimization algorithm through probabilistic treatment planning (PTP) and compare coverage of this method with margin-based planning. In this work, PTP eliminates explicit margins and optimizes directly on the estimated integral treatment dose to determine optimal patient dose in the presence of setup uncertainties. Twenty-eight prostate patient plans adhering to the RTOG-0126 criteria are optimized using both margin-based and PTP methods. Only random errors are considered. For margin-based plans, the planning target volume is created by expanding the clinical target volume (CTV) by 2.1 mm to accommodate the simulated 3 mm random setup uncertainty. Random setup uncertainties are incorporated into IMRT dose evaluation by convolving each beam's incident fluence with a sigma = 3 mm Gaussian prior to dose calculation. PTP optimization uses the convolved fluence to estimate dose to ensure CTV coverage during plan optimization. PTP-based plans are compared to margin-based plans with equal CTV coverage in the presence of setup errors based on dose-volume metrics. The sensitivity of the optimized plans to patient-specific setup uncertainty variations is assessed by evaluating dose metrics for dose distributions corresponding to halving and doubling of the random setup uncertainty used in the optimization. Margin-based and PTP-based plans show similar target coverage. A physician review shows that PTP is preferred for 21 patients, margin-based plans are preferred in 2 patients, no preference is expressed for 1 patient, and both autogenerated plans are rejected for 4 patients. For the PTP-based plans, the average CTV receiving the prescription dose decreases by 0.5%, while the mean dose to the CTV increases by 0.7%. The CTV tumor control probability (TCP) is the same for both methods with the exception

  6. Comparison of Bile Acids and Acetaminophen Protein Adducts in Children and Adolescents with Acetaminophen Toxicity.

    Directory of Open Access Journals (Sweden)

    Laura James

    Full Text Available Metabolomics approaches have enabled the study of new mechanisms of liver injury in experimental models of drug toxicity. Disruption of bile acid homeostasis is a known mechanism of drug induced liver injury. The relationship of individual bile acids to indicators of oxidative drug metabolism (acetaminophen protein adducts and liver injury was examined in children with acetaminophen overdose, hospitalized children with low dose exposure to acetaminophen, and children with no recent exposure to acetaminophen. Nine bile acids were quantified through targeted metabolomic analysis in the serum samples of the three groups. Bile acids were compared to serum levels of acetaminophen protein adducts and alanine aminotransferase. Glycodeoxycholic acid, taurodeoxycholic acid, and glycochenodeoxycholic acid were significantly increased in children with acetaminophen overdose compared to healthy controls. Among patients with acetaminophen overdose, bile acids were higher in subjects with acetaminophen protein adduct values > 1.0 nmol/mL and modest correlations were noted for three bile acids and acetaminophen protein adducts as follows: taurodeoxycholic acid (R=0.604; p<0.001, glycodeoxycholic acid (R=0.581; p<0.001, and glycochenodeoxycholic acid (R=0.571; p<0.001. Variability in bile acids was greater among hospitalized children receiving low doses of acetaminophen than in healthy children with no recent acetaminophen exposure. Compared to bile acids, acetaminophen protein adducts more accurately discriminated among children with acetaminophen overdose, children with low dose exposure to acetaminophen, and healthy control subjects. In children with acetaminophen overdose, elevations of conjugated bile acids were associated with specific indicators of acetaminophen metabolism and non-specific indicators of liver injury.

  7. Comparison of clindamycin 1% and benzoyl peroxide 5% gel to a novel composition containing salicylic acid, capryloyl salicylic acid, HEPES, glycolic acid, citric acid, and dioic acid in the treatment of acne vulgaris.

    Science.gov (United States)

    Baumann, Leslie S; Oresajo, Christian; Yatskayer, Margarita; Dahl, Amanda; Figueras, Kristian

    2013-03-01

    This study evaluated the tolerance and efficacy of 2 facial skin products in subjects with acne using the following acne treatments: 1) treatment A, a combination of salicylic acid, capryloyl salicylic acid, HEPES, glycolic acid, citric acid, and dioic acid, and 2) treatment B (BenzaClin®, clindamycin 1% and benzoyl peroxide 5% gel). The treatment design included the split-face application of treatment A and treatment B and the full-face application of the cleanser, moisturizer, and sunscreen. Data were collected through physician visual assessments, subject irritation questionnaires and assessments, along with clinical photography. Results showed similar tolerance and efficacy for both treatments.

  8. Content of Trans Fatty Acids in Human Cheek Epithelium: Comparison with Serum and Adipose Tissue

    Directory of Open Access Journals (Sweden)

    Ransi A. Abraham

    2013-01-01

    Full Text Available Studies pertaining to trans fatty acids (TFA, which have been implicated in development of chronic diseases, are more relevant in developing countries where nutrition transition is changing traditional habits and practices. Measuring TFA is an arduous task because of the need for fat biopsies. This study identifies a tissue, which can be easily accessed for analytical measurement of trans fatty acid. In this cross-sectional study, fatty acid in adipose tissue, cheek epithelium, and blood samples were assessed by gas chromatography. Spearman correlation coefficient was computed to study the correlation of fatty acid distribution among the three tissues. The correlation coefficient of total trans fatty acid between cheek epithelium and serum was 0.30 ( and between cheek epithelium and adipose tissue was 0.33 (. This study is the first to report trans fatty acid profile in cheek epithelium giving scope for utilizing the cheek epithelium as a tissue for objective assessment of trans fatty acid intake.

  9. Circulatory responses to nasotracheal intubation: comparison of GlideScope(R) videolaryngoscope and Macintosh direct laryngoscope

    Institute of Scientific and Technical Information of China (English)

    XUE Fu-shan; LI Xuan-ying; LIU Qian-jin; LIU He-ping; YANG Quan-yong; XU Ya-chao; LIAO Xu; LIU Yi

    2008-01-01

    Background The GlideScope videolaryngoscope (GSVL) has been shown to have no special advantage over theMacintosh direct laryngoscope (MDL) in attenuating the circulatory responses to orotracheal intubation, but no study has compared the circulatory responses to nasotracheal intubation (NTI) using the two devices. This prospective randomized clinical study was designed to determine whether there was a clinically relevant difference between the circulatory responses to NTI with the GSVL and the MDL.Methods Seventy-six adult patients were randomly allocated equally to the GSVL group and the MDL group. After induction of anesthesia, NTI was performed. Non-invasive blood pressure (BP) and heart rate (HR) were recorded before induction (baseline values) and immediately before intubation (post-induction values), at intubation and every minute for a further five minutes. During the observation, times required to reach the maximum values of systolic BP (SBP) and HR, times required for recovery of SBP and HR to postinduction values and incidence of SBP and HR percent changes>30% of baseline values were also noted. The product of HR and systolic BP, I.e. Rate pressure product (RPP), and the areas under SBP and HR vs. Time curves (AUCSBP and AUCHR) were calculated.Results The NTI with the GSVL resulted in significant increases in BP, HR and RPP compared to postinduction values, but these circulatory changes did not exceed baseline values. BPs at all measuring points, AUCSBP, maximum values of BP and incidence of SBP percent increase>30% of baseline value during the observation did not differ significantly between groups. However, HR and RPP at intubation and their maximum values, AUCHR and incidence of HR percent increase > 30% of baseline value were significantly higher in the MDL group than in the GSVL group. -times required for recovery of SBP and HR to postinduction values were significantly longer in the MDL group than in the GSVL group.Conclusions The pressor response to

  10. The direct conversion of sugars into 2,5-furandicarboxylic acid in a triphasic system.

    Science.gov (United States)

    Yi, Guangshun; Teong, Siew Ping; Zhang, Yugen

    2015-04-13

    A one-pot conversion of sugars into 2,5-furandicarboxylic acid (FDCA) is demonstrated in a triphasic system: tetraethylammonium bromide (TEAB) or water-methyl isobutyl ketone (MIBK)-water. In this reaction, sugars are first converted into 5-hydroxymethylfurfural (HMF) in TEAB or water (Phase I). The HMF in Phase I is then extracted to MIBK (Phase II) and transferred to water (Phase III), where HMF is converted into FDCA. Phase II plays multiple roles: as a bridge for HMF extraction, transportation and purification. Overall FDCA yields of 78 % and 50 % are achieved from fructose and glucose respectively.

  11. ATAF1 transcription factor directly regulates abscisic acid biosynthetic gene NCED3 in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Jensen, Michael Krogh; Lindemose, Søren; De Masi, Federico

    2013-01-01

    ATAF1, an Arabidopsis thaliana NAC transcription factor, plays important roles in plant adaptation to environmental stress and development. To search for ATAF1 target genes, we used protein binding microarrays and chromatin-immunoprecipitation (ChIP). This identified T[A,C,G]CGT[A,G] and TT[A,C,G...... abscisic acid (ABA) phytohormone biosynthetic gene NCED3. ChIP-qPCR and expression analysis showed that ATAF1 binding to the NCED3 promoter correlated with increased NCED3 expression and ABA hormone levels. These results indicate that ATAF1 regulates ABA biosynthesis....

  12. Transcription of the Escherichia coli fatty acid synthesis operon fabHDG is directly activated by FadR and inhibited by ppGpp.

    Science.gov (United States)

    My, Laetitia; Rekoske, Brian; Lemke, Justin J; Viala, Julie P; Gourse, Richard L; Bouveret, Emmanuelle

    2013-08-01

    In Escherichia coli, FadR and FabR are transcriptional regulators that control the expression of fatty acid degradation and unsaturated fatty acid synthesis genes, depending on the availability of fatty acids. In this report, we focus on the dual transcriptional regulator FadR. In the absence of fatty acids, FadR represses the transcription of fad genes required for fatty acid degradation. However, FadR is also an activator, stimulating transcription of the products of the fabA and fabB genes responsible for unsaturated fatty acid synthesis. In this study, we show that FadR directly activates another fatty acid synthesis promoter, PfabH, which transcribes the fabHDG operon, indicating that FadR is a global regulator of both fatty acid degradation and fatty acid synthesis. We also demonstrate that ppGpp and its cofactor DksA, known primarily for their role in regulation of the synthesis of the translational machinery, directly inhibit transcription from the fabH promoter. ppGpp also inhibits the fadR promoter, thereby reducing transcription activation of fabH by FadR indirectly. Our study shows that both ppGpp and FadR have direct roles in the control of fatty acid promoters, linking expression in response to both translation activity and fatty acid availability.

  13. Iron binding efficiency of polyphenols: Comparison of effect of ascorbic acid and ethylenediaminetetraacetic acid on catechol and galloyl groups.

    Science.gov (United States)

    Tamilmani, Poonkodi; Pandey, Mohan Chandra

    2016-04-15

    Dietary polyphenols are markedly studied for their antioxidant activity. They also have a negative impact on nutrition whereby they interfere with iron absorption. Common dietary polyphenols include: catechins, flavonols, flavanols, flavones, anthocyanins, proanthocyanidins and phenolic acids. Ascorbic acid (AA) and Ethylenediaminetetraacetic acid (EDTA) are commonly used to counter act this reaction and increase iron bioavailability. This study was aimed at determining the effect of AA and EDTA on the catechol or galloyl iron binding ability of pure phenolics, coffee and tea. Phenolic concentrations of 40, 80, 610, 240, 320, 400, 520 and 900 μg/ml were tested against six levels of AA and EDTA. These effects were studied in detail using Multivariate Analysis of Variance (MANOVA) with the hypothesis that there would be one or more mean differences between the ratio of enhancer and the different concentrations of samples tested. AA was found to be more efficient than EDTA in a way that lesser quantity is required for completely overcoming negative iron binding effects of polyphenols and similar samples.

  14. Ionic polymeric micelles based on chitosan and fatty acids and intended for wound healing. Comparison of linoleic and oleic acid.

    Science.gov (United States)

    Bonferoni, M C; Sandri, G; Dellera, E; Rossi, S; Ferrari, F; Mori, M; Caramella, C

    2014-05-01

    Chitosan is well known for its positive properties in wound healing. Also unsaturated fatty acids are described as able to accelerate tissue repairing mechanisms. In this work hydrophobically modified chitosan was obtained by ionic interaction with either oleic or linoleic acid. In aqueous environment self-assembling into nanoparticles occurred. The presence of hydrophobic domains, similar to those present in polymeric micelles, was demonstrated by changes in pyrene spectra. Both oleate and linoleate derivatives showed mucoadhesion behaviour. Cytotoxicity tests on human dermal fibroblasts demonstrated good biocompatibility of especially oleate derivatives. Clarithromycin, a poorly soluble model drug proposed for use in infected wounds was successfully encapsulated in both oleic and linoleic based polymeric micelles. The ionic structure of the carriers is responsible for their loosening at neutral pH and in the presence of salts. This behaviour should impair parenteral administration of the systems, but can be useful for topical delivery where the micelle components, chitosan and fatty acid, can play a positive role in dermal regeneration and tissue repairing.

  15. Comparison of several methods for the measurement of urinary hippuric acid as an index of toluene exposure.

    Directory of Open Access Journals (Sweden)

    Ogata,Masana

    1980-12-01

    Full Text Available The levels of hippuric acid in the urine of people exposed to toluene vapour were measured by paper chromatography, direct colorimetry, high performance liquid chromatography and gas chromatography. The control was a similar group not exposed to toluene vapour. The values were analyzed statistically, conversion equations calculated, and the propriety of these equation discussed. Since the three chromatographic methods gave similar values, the measurement of urinary hippuric acid by these methods can be used as an index of toluene exposure. The colorimetric method gave higher levels the chromatographic methods, especially for the urine of people not exposed to toluene. This may have been due to glycine conjugates (other than hippuric acid developing a similar color, resulting in elevated values for hippuric acid. This colorimetric method should be used with caution for biological evaluation of workers with low toluene exposure.

  16. Impact of methods used to express levels of circulating fatty acids on the degree and direction of associations with blood lipids in humans.

    Science.gov (United States)

    Sergeant, Susan; Ruczinski, Ingo; Ivester, Priscilla; Lee, Tammy C; Morgan, Timothy M; Nicklas, Barbara J; Mathias, Rasika A; Chilton, Floyd H

    2016-01-28

    Numerous studies have examined relationships between disease biomarkers (such as blood lipids) and levels of circulating or cellular fatty acids. In such association studies, fatty acids have typically been expressed as the percentage of a particular fatty acid relative to the total fatty acids in a sample. Using two human cohorts, this study examined relationships between blood lipids (TAG, and LDL, HDL or total cholesterol) and circulating fatty acids expressed either as a percentage of total or as concentration in serum. The direction of the correlation between stearic acid, linoleic acid, dihomo-γ-linolenic acid, arachidonic acid and DHA and circulating TAG reversed when fatty acids were expressed as concentrations v. a percentage of total. Similar reversals were observed for these fatty acids when examining their associations with the ratio of total cholesterol:HDL-cholesterol. This reversal pattern was replicated in serum samples from both human cohorts. The correlations between blood lipids and fatty acids expressed as a percentage of total could be mathematically modelled from the concentration data. These data reveal that the different methods of expressing fatty acids lead to dissimilar correlations between blood lipids and certain fatty acids. This study raises important questions about how such reversals in association patterns impact the interpretation of numerous association studies evaluating fatty acids and their relationships with disease biomarkers or risk.

  17. Expression and characterization of an enantioselective antigen-binding fragment directed against α-amino acids

    Science.gov (United States)

    Eleniste, Pierre P.; Hofstetter, Heike; Hofstetter, Oliver

    2013-01-01

    This work describes the design and expression of a stereoselective Fab that possesses binding properties comparable to those displayed by the parent monoclonal antibody. Utilizing mRNA from hybridoma clones that secrete a stereoselective anti-L-amino acid antibody, a corresponding biotechnologically produced Fab was generated. For that, appropriate primers were designed based on extensive literature and databank searches. Using these primers in PCR resulted in successful amplification of the VH, VL, CL and CH1 gene fragments. Overlap PCR was utilized to combine the VH and CH1 sequences and the VL and CL sequences, respectively, to obtain the genes encoding the HC and LC fragments. These sequences were separately cloned into the pEXP5-CT/TOPO expression vector and used for transfection of BL21(DE3) cells. Separate expression of the two chains, followed by assembly in a refolding buffer, yielded an Fab that was demonstrated to bind to L-amino acids but not to recognize the corresponding D-enantiomers. PMID:23827208

  18. Direct Comparison of Brookhaven Reflectivity Measurements with Free-Electron Theory

    Energy Technology Data Exchange (ETDEWEB)

    Bane, Karl L.F.

    2010-12-13

    The reflectivity at normal incidence of copper and aluminum samples was recently measured over a large frequency range at Brookhaven by one of us (JT). Then using the Kramers-Kroning integrals, and assuming the free-electron model of conductivity, the dependence of conductivity on frequency was obtained. The results seemed to suggest, for example, that the dc conductivities of the copper and evaporated aluminum samples are a factor of 3 lower than expected. We propose in this report, instead, directly fitting the free-electron model to the low frequency end of the reflectivity data. This fitting does not depend on the higher frequency results and on Kramers-Kronig integrations, but it does assume that the data at the low frequency end is sufficiently accurate. Note that for our LCLS wakefield studies, it is only over these (relatively) low frequencies that we need to know the electrical properties of the metals. The equations that relate reflectivity R with the free electron parameters dc conductivity {sigma} and relaxation time {tau} are: (1) {tilde {sigma}} = {sigma}/1-ikc{tau}; (2) {tilde n} = {radical} {tilde {epsilon}} = {radical}(1+4{pi}i{tilde k}c/{omega}); and (3) R = |{tilde n}-1/{tilde n} + 1|{sup 2}. The parameters are ac conductivity {tilde {sigma}}, index of refraction {tilde n}, dielectric constant {tilde {epsilon}}, and wave number k = {omega}/c, with {omega} frequency and c the speed of light. In Fig. 1 we show the ideal behavior of R for a reasonably good conducting metal, where {sigma} = 0.12 x 10{sup 17}/s and {tau} = 0.55 x 10{sup -14} s (solid line); these parameters are, respectively, 2% ({sigma}) and 20% ({tau}) of the nominal values for copper. The parameters were chosen so that the important features of R(k) could be seen easily in one plot. We see 3 distinct regions: (1) for low frequencies, k {approx}< 1/c{tau}, R continually decreases, with positive curvature, and with a low frequency asymptote of (1 - {radical}2kc/{pi}{sigma}); (2) for

  19. Comparison of the amino acid and peptide composition and postprandial response of beef, hydrolyzed chicken, and whey protein nutritional preparations

    Directory of Open Access Journals (Sweden)

    Christopher J. Detzel

    2016-10-01

    Full Text Available Background: Increasing dietary protein intake synergistically improves the effect of exercise to stimulate muscle protein synthesis. The purpose of this study was to evaluate the plasma amino acid response of two novel protein nutritional preparations, beef protein isolate (BeefISO™ and hydrolyzed chicken protein isolate (MyoCHX™. Methods: The postprandial plasma amino acid response over 3 hours was monitored in young adults (n=6 following consumption of 23 grams of WPC, BeefISO™, or MyoCHX™. Amino acid compositional analysis and molecular weight distributions of each protein were performed by HPLC. Statistical analyses were performed using one-way or two-way ANOVA where appropriate and corrected for multiple comparisons to account for the cross-over design. Results: Compositional evaluations revealed similar levels of essential and branched-chain amino acids for WPC and MyoCHX™. While the results of this study predictably demonstrated plasma amino acids levels increased following consumption of the different proteins, the kinetics of the postprandial response was unique to each protein source. WPC and MyoCHX™ were rapidly absorbed with maximum plasma amino acid concentrations observed at 30 and 15 min, respectively. The slightly faster absorption of MyoCHX™ was associated with the increased peptide content of MyoCHX™ (greater than 76% of protein is <2kDa. BeefISO™ exhibited sustained release characteristics as evidenced by increased post prandial amino acid concentrations after 3 hours. Conclusions: The protein preparations studied each had different amino acid profiles and absorption kinetics. WPC and MyoCHX™ contained a higher essential amino acid content and were rapidly absorbed with plasma amino acid concentrations peaking within 30 minutes following consumption. BeefISO™ contained a higher proportion of conditionally essential amino acids that steadily increased in plasma over 3 hours, indicating a sustained release

  20. Direct analysis of volatile fatty acids in marine sediment porewater by two-dimensional ion chromatography-mass spectrometry

    DEFF Research Database (Denmark)

    Glombitza, Clemens; Pedersen, Jeanette; Røy, Hans

    2014-01-01

    Volatile fatty acids (VFAs) are key intermediates in the microbial food web. However, the analysis of low concentrations of VFAs in marine porewater is hampered by interference from high concentrations of inorganic ions. Published methods often use sample pretreatment, including distillation...... or derivatization, to overcome this problem. This is not only labor intensive but also increases the risk of contamination. We have developed an analytical procedure that enables the direct quantification of several VFAs (formate, acetate, propionate, butyrate, valerate, pyruvate, and lactate) in marine porewater...

  1. Direct Electrochemistry of Cytochrome C on the Glassy Carbon Electrode Modified with 1-Pyrenebutyric Acid/MWNTs

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    With 1-Pyrenebutyric acid (PBA) and multiwalled carbon nanotubes (MWNTs), glassy carbon electrode modified was successfully prepared. In phosphate buffer solution (pH 7.0), the direct electrochemistry of cytochrome C (Cyt C) was realized. In the cyclic voltammetry experiment two pairs of redox peaks of Cyt C were observed at 0.018 V and -0.314 V (vs. SCE),respectively. The redox reaction at 0.018 V was diffusion controlled, while the redox reaction at -0.314 V was adsorption controlled.

  2. Comparisons between direct and inverse approaches in problems of recovering the true profile of a spectral line

    CERN Document Server

    Mijovic, S

    2003-01-01

    Computer-supported techniques are introduced in the evaluation of experimental data and obtaining the real profile of spectral lines. The direct and inverse approaches were used. The MINUIT program from the packets of CERN's library was used to solve direct problems. Tikhonov's regularization method was also applied to solve the same problems in an inverse manner. Model functions were introduced to check the applicability limitation of these methods and make a comparison between them as well. The advantages and disadvantages of these approaches were shown. The procedures were applied to the measured profiles of He II's spectral lines in a pulsed low-pressure arc. The chosen lines are He II Paschen-alpha (468.6 nm) in the visible region and Balmer-beta (121.5 nm) in the VUV spectral region. The range of experimental errors was determined where both approaches have given reliable results. It was found that we can obtain the real profile of He II 468.6 nm and He II 121.5 nm spectral lines, using the regularizati...

  3. Comparison of three joint simulator wear debris isolation techniques: acid digestion, base digestion, and enzyme cleavage.

    Science.gov (United States)

    Niedzwiecki, S; Klapperich, C; Short, J; Jani, S; Ries, M; Pruitt, L

    2001-08-01

    Quantification of ultrahigh molecular weight polyethylene (UHMWPE) wear debris remains a challenging task in orthopedic device analysis. Currently, the weight loss method is the only accepted practice for quantifying the amount of wear generated from a PE component. This technique utilizes loaded soak controls and weight differences to account for polymeric material lost through wear mechanisms. This method enables the determination of the amount of wear in the orthopedic device, but it provides no information about debris particulate size distribution. In order to shed light on wear mechanisms, information about the wear debris and its size distribution is necessary. To date, particulate isolation has been performed using the base digestion technique. The method uses a strong base, ultracentrifugation, and filtration to digest serum constituents and to isolate PE debris from sera. It should be noted that particulate isolation methods provide valuable information about particulate size distribution and may elucidate the mechanisms of wear associated with polymeric orthopedic implants; however, these techniques do not yet provide a direct measure of the amount of wear. The aim of this study is to present alternative approaches to wear particle isolation for analysis of polymer wear in total joint replacements without recourse to ultracentrifugation. Three polymer wear debris isolation techniques (the base method, an acid treatment, and an enzymatic digestion technique) are compared for effectiveness in simulator studies. A requirement of each technique is that the wear particulate must be completely devoid of serum proteins in order to effectively image and count these particles. In all methods the isolation is performed through filtration and chemical treatment. Subsequently, the isolated polymer particles are imaged using scanning electron microscopy and quantified with digital image analysis. The results from this study clearly show that isolation can be

  4. Comparison between the single-bubble sonoluminescences in sulfuric acid and in water

    Institute of Scientific and Technical Information of China (English)

    HUANG Wei; CHEN WeiZhong; GAO XianXian; LIANG Yue

    2009-01-01

    Single-bubble sonoluminescence (SBSL) is achieved with strong stability in sulfuric acid solutions. Bubble dynamics and the SBSL spectroscopy in the sulfuric acid solutions with different concentrations are studied with phase-locked integral stroboscopic photography method and a spectrograph, respectively. The experimental results are compared with those in water. The SBSL in sulfuric acid is brighter than that in water. One of the most important reasons for that is the larger viscosity of sulfuric acid, which results in the larger ambient radius and thus the more contents of luminous material inside the bubble. However, sonoluminescence bubble's collapse in sulfuric acid is less violent than that in water, and the corresponding blackbody radiation temperature of the SBSL in sulfuric acid is lower than that in water.

  5. Comparison between the single-bubble sonoluminescences in sulfuric acid and in water

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Single-bubble sonoluminescence (SBSL) is achieved with strong stability in sulfuric acid solutions. Bubble dynamics and the SBSL spectroscopy in the sulfuric acid solutions with different concentra- tions are studied with phase-locked integral stroboscopic photography method and a spectrograph, respectively. The experimental results are compared with those in water. The SBSL in sulfuric acid is brighter than that in water. One of the most important reasons for that is the larger viscosity of sulfuric acid, which results in the larger ambient radius and thus the more contents of luminous material inside the bubble. However, sonoluminescence bubble’s collapse in sulfuric acid is less violent than that in water, and the corresponding blackbody radiation temperature of the SBSL in sulfuric acid is lower than that in water.

  6. Dendrite Spacing Selection during Directional Solidification of Pivalic Acid-Ethanol System

    Institute of Scientific and Technical Information of China (English)

    Myung-Jin Suk; Young-Min Park; Youn-Che Kim

    2008-01-01

    Unidirectional solidification of pivalic acid (PVA)-ethanol (Eth) mixture was performed to examine whether an allowable range of primary dendrite spacing definitely exists at a given growth velocity and how the range is history-dependent. PVA-0.59 wt pct Eth was unidirectionally solidified in the range of growth velocity 0.5-64 μm/s at the temperature gradient of 2.3 K/mm. Sequential change in growth velocity was imposed to determine the upper and lower limits for the allowable range of stable spacing. An allowable range of the steady state primary spacing was observed at a given growth velocity, and the extent of the range seems to be dependent on the degree to which step-increase or step-decrease in growth velocity is accomplished. As the degree of sequential change in growth velocity increases, the history-dependence of the selection for the primary dendrite spacing tends to disappear.

  7. Investigation of antibacterial activity of Lactic Acid Bacteria isolated from traditional kordish cheese in comparison with commercial strains

    Directory of Open Access Journals (Sweden)

    Fereshteh Tofangsazan

    2013-12-01

    Full Text Available Background and Aim: The health benefits of lactic acid bacteria in human, especially their anti-pathogenic properties has been the focus of recent interests. The objective of this study was to investigate the antibacterial activity of lactic acid bacteria (LAB isolated from traditional Kurdish cheese against a few bacterial pathogens. Materials and Methods: The cell free culture supernatant of LAB isolated from Kurdish cheese which was treated with heat and NaOH were tested for their antibacterial activity by Agar Disk Diffusion method. Moreover, Minimum Inhibition Concentration and Co-aggregation of LAB against pathogens were determined. Each test was repeated for three times. Results: The LAB isolates, in comparison with commercial lactic acid bacteria, showed suitable antibacterial activity. Heating the bacterial supernatant eliminated its anti-bacterial property; however, alkali treatment did not have any effect. The Minimum Inhibition Concentration did not show significant differences between native and commercial lactic acid bacteria; however, the native LAB showed suitable co-aggregation with pathogens. Conclusion: Traditional lactic acid bacteria and their metabolites can inhibit growth of pathogens. This shows the positive role of LAB in human health which necessitates their increase usage as natural antimicrobial agent.

  8. A directional Secular Variation Curve for Greece for the last 4500 years: Comparison with regional and global geomagnetic field models

    Science.gov (United States)

    de Marco, E.; Tema, E.; Lanos, P.; Kondopoulou, D.

    2009-12-01

    A total of 64 Greek archaeomagnetic directional data have been used for the establishment of the variation of the Earth’s magnetic field in Greece over the past 4500 years. Most of the data come from archaeological material but some data from Santorini lava flows are also included. The data ages range from Minoan times (~2500 BC) up to the last century with a gap around 10th to 6th century BC. All data have been relocated to Athens (37.97° N, 23.72° E) using the virtual geomagnetic pole method. Data coming from direct measurements available in Greece for the last four centuries have been also added. The secular variation (SV) curves for declination and inclination have been obtained using hierarchical Bayesian modelling. For comparison, the dataset has been also analysed using the bi-variate moving average window technique with 150 years time window shifted by 75 years. The obtained smoothed curves accompanied by a 95 % confidence envelope are compared with archaeomagnetic data from Mediterranean area and with SV curves from nearby countries. The Greek curves have also been compared with the predictions of the SCHA.DIF.3K regional and the CALS7K and ARCH3K global geomagnetic field models. Despite the differences recognised between these models, the Greek archaeomagnetic SV curve is in reasonably good agreement with their basic trends. The proposed directional SV curve can contribute, together with the intensity SV curve previously published for Greece, to the reliable archaeomagnetic dating of Greek artefacts based on the full description of the Earth’s magnetic field (declination, inclination, intensity). It is clear that the continuous update of the dataset with new results from well-dated archaeological material will increase the precision of the SV curve, especially for the time periods poorly covered by data.

  9. Molecular dynamics simulations of the amino acid-ZnO (10-10) interface: A comparison between density functional theory and density functional tight binding results

    Energy Technology Data Exchange (ETDEWEB)

    Holthaus, Svea große; Köppen, Susan, E-mail: koeppen@hmi.uni-bremen.de; Frauenheim, Thomas; Ciacchi, Lucio Colombi [Bremen Centre for Computational Materials Science, University of Bremen, 28359 Bremen (Germany)

    2014-06-21

    We investigate the adsorption behavior of four different amino acids (glutamine, glutamate, serine, cysteine) on the zinc oxide (101{sup ¯}0) surface, comparing the geometry and energy associated with a number of different adsorption configurations. In doing this, we highlight the benefits and limits of using density-functional tight-binding (DFTB) with respect to standard density functional theory (DFT). The DFTB method is found to reliably reproduce the DFT adsorption geometries. Analysis of the adsorption configurations emphasizes the fundamental role of the first hydration layer in mediating the interactions between the amino acids and the surface. Direct surface-molecule bonds are found to form predominantly via the carboxylate groups of the studied amino acids. No surface-mediated chemical reactions are observed, with the notable exception of a proton transfer from the thiol group of cysteine to a hydroxyl group of the surface hydration layer. The adsorption energies are found to be dominated both by the formation of direct or indirect surface-molecule hydrogen bonds, but also by the rearrangement of the hydrogen-bond network in surface proximity in a non-intuitive way. Energetic comparisons between DFTB and DFT are made difficult on one side by the long time necessary to achieve convergence of potential energy values in MD simulations and on the other side by the necessity of including higher-order corrections to DFTB to obtain a good description of the hydrogen bond energetics. Overall, our results suggest that DFTB is a good reference method to set the correct chemical states and the initial geometries of hybrid biomolecule/ZnO systems to be simulated with non-reactive force fields.

  10. Comparison of complexation properties of humic acids and simple organic ligands

    Directory of Open Access Journals (Sweden)

    Martina Klucakova*

    2010-12-01

    Full Text Available Simple organic compounds as citric acid, phthalic acid, salicylicacid, EDTA, hydroquinone and pyrocatechol were used as structural models of active sites of humic acids. Combination of high resolution ultrasound spectrometry with potentiometry,conductometry and UV/VIS spectrometry were utilized forcomplexation of copper (II ions by humic acids and modelcompounds. Changes in the slope of measured quantities were used to find the saturation of binding. Ultrasound spectrometry showed follow changes of hydration of interacting species. The differences observed for individual model compounds show that there are active centres not only with various strength and stability of formed complexes but also with their various rigidity and ability of conformational changes.

  11. Comparison of XAD macroporous resins for the concentration of fulvic acid from aqueous solution

    Science.gov (United States)

    Aiken, G.R.

    1979-01-01

    Five macroreticular, nonlonlc AmberlHe XAD resins were evaluated for concentration and Isolation of fulvlc acid from aqueous solution. The capacity of each resin for fulvlc acid was measured by both batch and column techniques. Elution efficiencies were determined by desorptlon with 0.1 N NaOH. Highest recoveries were obtained with the acrylic ester resins which proved to be most efficient for both adsorption and elution of fulvlc acid. Compared to the acrylic ester resins, usefulness of the styrene dvlnybenzene resins to remove fulvlc acid is limited because of slow diffusion-controlled adsorption and formation of charge-transfer complexes, which hinders elution. ?? 1979 American Chemical Society.

  12. Comparison between liquid and solid acids catalysts on reducing sugars conversion from furfural residues via pretreatments.

    Science.gov (United States)

    Lin, Keying; Ma, Baojun; Sun, Yuan; Liu, Wanyi

    2014-09-01

    Liquid sulphuric acid is adopted and compared with carbon-based sulfonated solid acids (coal tar-based and active carbon-based) for furfural residues conversion into reducing sugars. The optimum hydrolysis conditions of liquid acid are at 4% of sulphuric acid, 25:1 of liquid and solid ratio, 175°C of reaction temperature and 120 min of reaction time. The reducing sugar yields are reached over 60% on liquid acid via NaOH/H2O2, NaOH/microwave and NaOH/ultrasonic pretreatments, whereas only over 30% on solid acids. The TOFs (turnover number frequency) via NaOH/H2O2 pretreatments are 0.093, 0.020 and 0.023 h(-1) for liquid sulphuric acid, coal tar-based and active carbon-based solid acids catalysts, respectively. Considering the efficiency, cost and environment factors, the liquid and solid acids have their own advantages of potential commercial application values.

  13. Multicenter evaluation of the Quidel Lyra Direct C. difficile nucleic acid amplification assay.

    Science.gov (United States)

    Beck, Eric T; Buchan, Blake W; Riebe, Katherine M; Alkins, Brenda R; Pancholi, Preeti; Granato, Paul A; Ledeboer, Nathan A

    2014-06-01

    Clostridium difficile is a Gram-positive bacterium commonly found in health care and long-term-care facilities and is the most common cause of antibiotic-associated diarrhea. Rapid detection of this bacterium can assist physicians in implementing contact precautions and appropriate antibiotic therapy in a timely manner. The purpose of this study was to compare the clinical performance of the Quidel Lyra Direct C. difficile assay (Lyra assay) (Quidel, San Diego, CA) to that of a direct cell culture cytotoxicity neutralization assay (CCNA) and enhanced toxigenic culture. This study was performed at three geographically diverse laboratories within the United States using residual stool specimens submitted for routine C. difficile testing. Residual samples were tested using the Lyra assay on three real-time PCR platforms, and results were compared to those for direct CCNA and enhanced toxigenic culture. The test results for all platforms were consistent across all three test sites. The sensitivity and specificity of the Lyra assay on the SmartCycler II, ABI 7500 Fast DX, and ABI QuantStudio DX instruments compared to CCNA were 90.0% and 93.3%, 95.0% and 94.2%, and 93.8% and 95.0%, respectively. Compared to enhanced toxigenic culture, the sensitivity and specificity of the Lyra assay on the SmartCycler II, ABI 7500, and QuantStudio instruments were 82.1% and 96.9%, 89.3% and 98.8%, and 85.7% and 99.0%, respectively. Overall, the Lyra assay is easy to use and versatile and compares well to C. difficile culture methods.

  14. Determination of free fatty acids in pharmaceutical lipids by ¹H NMR and comparison with the classical acid value.

    Science.gov (United States)

    Skiera, Christina; Steliopoulos, Panagiotis; Kuballa, Thomas; Diehl, Bernd; Holzgrabe, Ulrike

    2014-05-01

    Indices like acid value, peroxide value, and saponification value play an important role in quality control and identification of lipids. Requirements on these parameters are given by the monographs of the European pharmacopeia. (1)H NMR spectroscopy provides a fast and simple alternative to these classical approaches. In the present work a new (1)H NMR approach to determine the acid value is described. The method was validated using a statistical approach based on a variance components model. The performance under repeatability and in-house reproducibility conditions was assessed. We applied this (1)H NMR assay to a wide range of different fatty oils. A total of 305 oil and fat samples were examined by both the classical and the NMR method. Except for hard fat, the data obtained by the two methods were in good agreement. The (1)H NMR method was adapted to analyse waxes and oleyloleat. Furthermore, the effect of solvent and in the case of castor oil the effect of the oil matrix on line broadening and chemical shift of the carboxyl group signal are discussed.

  15. Direct electrochemistry and electrocatalysis of horseradish peroxidase with hyaluronic acid-ionic liquid-cadmium sulfide nanorod composite material

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Zhihong [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China); Li Xia; Wang Yan [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Zeng Yan [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China); Sun Wei, E-mail: sunwei@qust.edu.cn [College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266042 (China); Huang Xintang [Institute of Nano-Science and Technology Center, Huazhong Normal University, Wuhan 430079 (China)

    2010-06-18

    A new composite material consisted of hyaluronic acid (HA), ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM]BF{sub 4}) and cadmium sulfide (CdS) nanorod was fabricated and used for the immobilization of horseradish peroxidase (HRP) on the surface of a carbon ionic liquid electrode (CILE), which was prepared with 1-ethyl-3-methyl-imidazolium ethylsulphate ([EMIM]EtOSO{sub 3}) as modifier. Spectroscopic results indicated that HRP remained its native structure in the composite film. Based on the synergistic effect of the materials used, an obvious promotion to the direct electron transfer efficient between HRP and CILE was achieved with a pair of well-defined redox peaks appeared in 0.1 mol L{sup -1} phosphate buffer solution, indicating the realization of the direct electrochemistry of HRP. The immobilized HRP showed good electrocatalytic activity towards the reduction of trichloroacetic acid and H{sub 2}O{sub 2} with the electrochemical parameters calculated. Based on the fabricated electrode, a new third-generation electrochemical biosensor was constructed with good stability and reproducibility.

  16. The natural phytochemical dehydroabietic acid is an anti-aging reagent that mediates the direct activation of SIRT1.

    Science.gov (United States)

    Kim, Juewon; Kang, Young-Gyu; Lee, Jee-young; Choi, Dong-hwa; Cho, Young-uk; Shin, Jae-Min; Park, Jun Seong; Lee, John Hwan; Kim, Wan Gi; Seo, Dae Bang; Lee, Tae Ryong; Miyamoto, Yusei; No, Kyoung Tai

    2015-09-05

    Dehydroabietic acid (DAA) is a naturally occurring diterpene resin acid of confers, such as pinus species (P. densiflora, P. sylvestris) and grand fir (Abies grandis), and it induces various biological actions including antimicrobial, antiulcer, and cardiovascular activities. The cellular targets that mediate these actions are largely unknown yet. In this report, we suggest that DAA is an anti-aging reagent. DAA has lifespan extension effects in Caenorhabditis elegans, prevents lipofuscin accumulation, and prevents collagen secretion in human dermal fibroblasts. We found that these anti-aging effects are primarily mediated by SIRT1 activation. Lifespan extension effects by DAA were ameliorated in sir-2.1 mutants and SIRT1 protein expression was increased, resulting in the deacetylation of SIRT1 target protein PGC-1α. Moreover, DAA binds directly to the SIRT1 protein independent of the SIRT1 substrate NAD(+) levels. Through a molecular docking study, we also propose a binding model for DAA-SIRT1. Taken together, our results demonstrate that the anti-aging effects are the first identified biological property of DAA and that the direct activation of SIRT1 enzymatic activity suggests the potential use of this natural diterpene, or related compounds, in age-related diseases or as a preventive reagent against the aging process.

  17. The direct electrochemistry of glucose oxidase based on the synergic effect of amino acid ionic liquid and carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Amino acid ionic liquids(AAILs) have attracted much attention due to their special chemical and physical properties,especially their outstanding biocompatibility and truly green aspect.In this work,a novel electrochemical biosensing platform based on AAILs/carbon nanotubes(CNTs) composite was fabricated.AAILs were used as a novel solvent for glucose oxidase(GOD) and the GOD-AAILs/CNTs/GC electrode was conveniently prepared by immersing the carbon nanotubes(CNTs) modified glassy carbon(GC) electrode into AAILs containing GOD.The direct electrochemistry of GOD on the GOD-AAILs/CNTs/GC electrode has been investigated and a pair of reversible peaks was obtained by cyclic voltammetry.The immobilized glucose oxidase could retain bioactivity and catalyze the reduction of dissolved oxygen.Due to the synergic effect of AAILs and CNTs,the GOD-AAILs/CNTs/GC electrode shows excellent electrocatalytic activity towards glucose with a linear range from 0.05 to 0.8 mM and a detection limit of 5.5 μM(S/N = 3).Furthermore,the biosensor exhibits good stability and ability to exclude the interference of commonly coexisting uric and ascorbic acid.Therefore,AAILs/CNTs composite can be a good candidate biocompatible material for the direct electrochemistry of the redox-active enzyme and the construction of third-generation enzyme sensors.

  18. Direct determination of mercury in cosmetic samples by isotope dilution inductively coupled plasma mass spectrometry after dissolution with formic acid

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Ying; Shi, Zeming; Zong, Qinxia; Wu, Peng; Su, Jing [Sichuan Provincial Key Laboratory of Nuclear Technology in Geology, College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059 (China); Liu, Rui, E-mail: liur.ray@gmail.com [Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institutions, College of Materials and Chemistry and Chemical Engineering, Chengdu University of Technology, Chengdu 610059 (China)

    2014-02-17

    Graphical abstract: -- Highlights: •Simple, sensitive, and accurate method is established for mercury determination in cosmetics. •The sample preparation procedure is highly simplified. •Isotope dilution efficiently eliminates matrix effect. •First report of using formic acid based method in combination with PVG-ID-ICP MS for mercury quantitation in cosmetics. -- Abstract: A new method was proposed for the accurate determination of mercury in cosmetic samples based on isotopic dilution (ID)-photochemical vapor generation (PVG)-inductively coupled plasma mass spectrometry (ICP MS) measurement. Cosmetic samples were directly dissolved in formic acid solution and subsequently subjected to PVG for the reduction of mercury into vapor species following by ICP MS detection. Therefore, the risks of analyte contamination and loss were avoided. Highly enriched {sup 201}Hg isotopic spike is added to cosmetics and the isotope ratios of {sup 201}Hg/{sup 202}Hg were measured for the quantitation of mercury. With ID calibration, the influences originating from sample matrixes for the determination of mercury in cosmetic samples have been efficiently eliminated. The effects of several experimental parameters, such as the concentration of the formic acid, and the flow rates of carrier gas and sample were investigated. The method provided good reproducibility and the detection limits were found to be 0.6 pg mL{sup −1}. Finally, the developed method was successfully applied for the determination of mercury in six cosmetic samples and a spike test was performed to verify the accuracy of the method.

  19. Liver-specific cytochrome P450 CYP2C22 is a direct target of retinoic acid and a retinoic acid-metabolizing enzyme in rat liver.

    Science.gov (United States)

    Qian, Linxi; Zolfaghari, Reza; Ross, A Catharine

    2010-07-01

    Several cytochrome P450 (CYP) enzymes catalyze the C4-hydroxylation of retinoic acid (RA), a potent inducer of cell differentiation and an agent in the treatment of several diseases. Here, we have characterized CYP2C22, a member of the rat CYP2C family with homology to human CYP2C8 and CYP2C9. CYP2C22 was expressed nearly exclusively in hepatocytes, where it was one of the more abundant mRNAs transcripts. In H-4-II-E rat hepatoma cells, CYP2C22 mRNA was upregulated by all-trans (at)-RA, and Am580, a nonmetabolizable analog of at-RA. In comparison, in primary human hepatocytes, at-RA increased CYP2C9 but not CYP2C8 mRNA. Analysis of the CYP2C22 promoter region revealed a RA response element (5'-GGTTCA-(n)5-AGGTCA-3') in the distal flanking region, which bound the nuclear hormone receptors RAR and RXR and which was required for transcriptional activation response of this promoter to RA in CYP2C22-luciferase-transfected RA-treated HepG2 cells. The cDNA-expressed CYP2C22 protein metabolized [3H]at-RA to more polar metabolites. While long-chain polyunsaturated fatty acids competed, 9-cis-RA was a stronger competitor. Our studies demonstrate that CYP2C22 is a high-abundance, retinoid-inducible, hepatic P450 with the potential to metabolize at-RA, providing additional insight into the role of the CYP2C gene family in retinoid homeostasis.

  20. Direct Determination of Chitosan–Mucin Interactions Using a Single-Molecule Strategy: Comparison to Alginate–Mucin Interactions

    Directory of Open Access Journals (Sweden)

    Kristin E. Haugstad

    2015-01-01

    Full Text Available Aqueous chitosan possesses attractive interaction capacities with various molecular groups that can be involved in hydrogen bonds and electrostatic and hydrophobic interactions. In the present paper, we report on the direct determination of chitosan–mucin molecular pair interactions at various solvent conditions as compared to alginate–mucin interactions. Two chitosans of high molecular weight with different degrees of acetylation—thus possessing different solubility profiles in aqueous solution as a function of pH and two alginates with different fractions of α-guluronic acid were employed. The interaction properties were determined through a direct unbinding assay at the single-molecular pair level using an atomic force microscope. When probed against immobilized mucin, both chitosans and alginates revealed unbinding profiles characteristic of localized interactions along the polymers. The interaction capacities and estimated parameters of the energy landscapes of the pairwise chitosan–mucin and alginate–mucin interactions are discussed in view of possible contributions from various fundamental forces. Signatures arising both from an electrostatic mechanism and hydrophobic interaction are identified in the chitosan–mucin interaction properties. The molecular nature of the observed chitosan–mucin and alginate–mucin interactions indicates that force spectroscopy provides fundamental insights that can be useful in understanding the surface binding properties of other potentially mucoadhesive polymers.

  1. Use of a Boron Doped Spherical Phantom for the Investigation of Neutron Directional Properties: Comparison Between Experiment and MCNP Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Drake, P.; Kierkegaard, J

    1999-07-01

    A boron doped 19 cm diameter spherical phantom was constructed to give information on the direction of neutrons inside the Ringhals 4 containment. The phantom was made of 40% paraffin and 60% boric acid. 10B contributes 2% of the total phantom weight. The phantom was tested for its angular sensitivity to neutrons. The response was tested with a {sup 252}Cf source and with a Monte Carlo calculation (MCNP) simulating a {sup 252}Cf source. In these investigations the phantom showed a strong directional response. However, there was only a fair correspondence between the experiment and the simulation. The discrepancies are, at least in part, due to the difference in energy and angular response of the dosemeters as compared with the idealised response characteristics in the MCNP calculation. In the MCNP calculation the experimental conditions were not fully simulated. The investigations also showed that the addition of boron to the phantom reduces the leakage of thermalised neutrons from the phantom, and the production of neutron induced photons in the phantom to insignificant levels. (author)

  2. A Comparison of Different Teaching Designs of "Acids and Bases" Subject

    Science.gov (United States)

    Ültay, Neslihan; Çalik, Muammer

    2016-01-01

    Inability to link the acid-base concepts with daily life phenomena (as contexts) highlights the need for further research on the context-based acid-base chemistry. In this vein, the aim of this study is to investigate the effects of different teaching designs (REACT strategy, 5Es learning model and traditional (existing) instruction) relevant with…

  3. Comparison of pH-sensitive degradability of maleic acid amide derivatives.

    Science.gov (United States)

    Kang, Sunyoung; Kim, Youngeun; Song, Youngjun; Choi, Jin Uk; Park, Euddeum; Choi, Wonmin; Park, Jeongseon; Lee, Yan

    2014-05-15

    We synthesized five maleic acid amide derivatives (maleic, citraconic, cis-aconitic, 2-(2'-carboxyethyl) maleic, 1-methyl-2-(2'-carboxyethyl) maleic acid amide), and compared their degradability for the future development of pH-sensitive biomaterials with tailored kinetics of the release of drugs, the change of charge density, and the degradation of scaffolds. The degradation kinetics was highly dependent upon the substituents on the cis-double bond. Among the maleic acid amide derivatives, 2-(2'-carboxyethyl) maleic acid amide with one carboxyethyl and one hydrogen substituent showed appropriate degradability at weakly acidic pH, and the additional carboxyl group can be used as a pH-sensitive linker.

  4. Zwitterionic chiral stationary phases based on cinchona and chiral sulfonic acids for the direct stereoselective separation of amino acids and other amphoteric compounds.

    Science.gov (United States)

    Zhang, Tong; Holder, Emilie; Franco, Pilar; Lindner, Wolfgang

    2014-06-01

    An extensive series of free amino acids and analogs were directly resolved into enantiomers (and stereoisomers where appropriate) by HPLC on zwitterionic chiral stationary phases (Chiralpak ZWIX(+) and Chiralpak ZWIX(-)). The interaction and chiral recognition mechanisms were based on the synergistic double ion-paring process between the analyte and the chiral selectors. The chiral separation and elution order were found to be predictable for primary α-amino acids with apolar aliphatic side chains. A systematic investigation was undertaken to gain an insight into the influence of the structural features on the enantiorecognition. The presence of polar and/or aromatic groups in the analyte structure is believed to tune the double ion-paring equilibrium by the involvement of the secondary interaction forces such as hydrogen bonding, Van der Waals forces and π-π stacking in concert with steric parameters. The ZWIX chiral columns were able to separate enantiomers and stereoisomers of various amphoteric compounds with no need for precolumn derivatization. Column switching between ZWIX(+) and ZWIX(-) is believed to be an instrumental tool to reverse or control the enantiomers elution order, due to the complementarity of the applied chiral selectors.

  5. Synthetic Studies on Tricyclic Diterpenoids: Direct Allylic Amination Reaction of Isopimaric Acid Derivatives.

    Science.gov (United States)

    Timoshenko, Mariya A; Kharitonov, Yurii V; Shakirov, Makhmut M; Bagryanskaya, Irina Yu; Shults, Elvira E

    2016-02-01

    A selective synthesis of 7- or 14-nitrogen containing tricyclic diterpenoids was completed according to a strategy in which the key step was the catalyzed direct allylic amination of methyl 14α-hydroxy-15,16-dihydroisopimarate with a wide variety of nitrogenated nucleophiles. It was revealed that the selectivity of the reaction depends on the nature of nucleophile. The catalyzed reaction of the mentioned diterpenoid allylic alcohol with 3-nitroaniline, 3-(trifluoromethyl)aniline, and 4-(trifluoromethyl)aniline yield the subsequent 7α-, 7β- and 14αnitrogen-containing diterpenoids. The reaction with 2-nitroaniline, 4-nitro-2-chloroaniline, 4-methoxy-2-nitroaniline, phenylsulfamide, or tert-butyl carbamate proceeds with the formation of 7α-nitrogen-substituted diterpenoids as the main products.

  6. Comparison of immobilized poly-L-aspartic acid and poly-L-glutamic acid for chelation of metal cations

    Energy Technology Data Exchange (ETDEWEB)

    Malachowski, Lisa; Holcombe, James A

    2004-07-26

    Poly-L-aspartic acid (PLAsp) and poly-L-glutamic acid (PLGlu) were individually immobilized onto controlled pore glass (CPG) and compared according to their metal-binding capabilities in a solution of pH 7.0. The metal-binding capacities were calculated through the analysis of breakthrough curves generated by monitoring the metal concentrations on a flow injection-flame atomic absorption system. Capacities for individual metals were comparable and in the order of Cu{sup 2+} >> Pb{sup 2+} > Ni{sup 2+} {approx} Cd{sup 2+} > Co{sup 2+} > Mn{sup 2+} >> Na{sup +}. Elemental combustion analysis yielded polymer coverage on the CPG of approximately 4 x 10{sup 12} to 5 x 10{sup 12} chains/cm{sup 2}, when average chain lengths were used in the calculations. Formation constants and site capacities of both polymers for Cd{sup 2+} were determined through equilibrium and breakthrough studies. The maximum log K values for the strong sites were determined to be {approx}13 for both PLAsp and for PLGlu. Additionally, the metal selectivity of PLAsp and PLGlu was evaluated when breakthrough curves were run with several metals present in solution at one time. Both polymers showed selectivities in the order of their single metal-binding capacities, i.e., Cu{sup 2+} > Pb{sup 2+} > Ni{sup 2+} {approx} Cd{sup 2+}. Both polymers exhibited similar binding trends and binding strengths for all of the metals studied. This likely reflects the absence of a predetermined tertiary structure of the polymers on the surface and the relatively high residue-per-metal ratio ({approx}20:1), which places less stringent requirements on the steric hindrance between the side chains and the resultant 'wrapping' of the peptide around the metal.

  7. Direct interaction between EgFABP1, a fatty acid binding protein from Echinococcus granulosus, and phospholipid membranes.

    Directory of Open Access Journals (Sweden)

    Jorge L Porfido

    Full Text Available BACKGROUND: Growth and maintenance of hydatid cysts produced by Echinococcus granulosus have a high requirement for host lipids for biosynthetic processes, membrane building and possibly cellular and developmental signalling. This requires a high degree of lipid trafficking facilitated by lipid transporter proteins. Members of the fatty acid binding protein (FABP family have been identified in Echinococcus granulosus, one of which, EgFABP1 is expressed at the tegumental level in the protoscoleces, but it has also been described in both hydatid cyst fluid and secretions of protoscoleces. In spite of a considerable amount of structural and biophysical information on the FABPs in general, their specific functions remain mysterious. METHODOLOGY/PRINCIPAL FINDINGS: We have investigated the way in which EgFABP1 may interact with membranes using a variety of fluorescence-based techniques and artificial small unilamellar vesicles. We first found that bacterial recombinant EgFABP1 is loaded with fatty acids from the synthesising bacteria, and that fatty acid binding increases its resistance to proteinases, possibly due to subtle conformational changes induced on EgFABP1. By manipulating the composition of lipid vesicles and the ionic environment, we found that EgFABP1 interacts with membranes in a direct contact, collisional, manner to exchange ligand, involving both ionic and hydrophobic interactions. Moreover, we observed that the protein can compete with cytochrome c for association with the surface of small unilamellar vesicles (SUVs. CONCLUSIONS/SIGNIFICANCE: This work constitutes a first approach to the understanding of protein-membrane interactions of EgFABP1. The results suggest that this protein may be actively involved in the exchange and transport of fatty acids between different membranes and cellular compartments within the parasite.

  8. Fast-track applications: The potential for direct delivery of proteins and nucleic acids to plant cells for the discovery of gene function

    Directory of Open Access Journals (Sweden)

    Roberts Michael R

    2005-12-01

    Full Text Available Abstract In animal systems, several methods exist for the direct delivery of nucleic acids and proteins into cells for functional analysis. Until recently, these methods have not been applied to plant systems. Now, however, several preliminary reports suggest that both nucleic acids and proteins can also be delivered into plant cells by very simple, direct application. This promises to open the way for high-throughput screening for gene function in a range of plant species.

  9. Self-assembled platinum nanoparticles on sulfonic acid-grafted graphene as effective electrocatalysts for methanol oxidation in direct methanol fuel cells

    Science.gov (United States)

    Lu, Jinlin; Li, Yanhong; Li, Shengli; Jiang, San Ping

    2016-02-01

    In this article, sulfonic acid-grafted reduced graphene oxide (S-rGO) were synthesized using a one-pot method under mild conditions, and used as Pt catalyst supports to prepare Pt/S-rGO electrocatalysts through a self-assembly route. The structure, morphologies and physicochemical properties of S-rGO were examined in detail by techniques such as atomic force microscope (AFM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The S-rGO nanosheets show excellent solubility and stability in water and the average particle size of Pt nanoparticles supported on S-rGO is ~3.8 nm with symmetrical and uniform distribution. The electrocatalytic properties of Pt/S-rGO were investigated for methanol oxidation reaction (MOR) in direct methanol fuel cells (DMFCs). In comparison to Pt supported on high surface area Vulcan XC-72 carbon (Pt/VC) and Pt/rGO, the Pt/S-rGO electrocatalyst exhibits a much higher electrocatalytic activity, faster reaction kinetics and a better stability. The results indicate that Pt/S-rGO is a promising and effective electrocatalyst for MOR of DMFCs.

  10. Does kainic acid induce partial brain lesion in an invertebrate model: sepia officinalis? Comparison with electrolytic lesion.

    Science.gov (United States)

    Graindorge, Nicolas; Jozet-Alves, Christelle; Chichery, Raymond; Dickel, Ludovic; Bellanger, Cécile

    2008-10-31

    The present study investigates the feasibility of excitotoxic lesions in the cuttlefish in the mapping of brain functions in Cephalopods. Adult animals were injected locally with a neurotoxin, kainic acid. The brain region receiving the neurotoxin was the vertical lobe, a key brain structure for learning and memory processes. Brain damage induced by these injections was evaluated using different histological stainings: hematoxilin-eosin, Fink-Heimer and DAPI. The results were compared with histological changes after electrolytic lesion of the vertical lobe. Neurodegeneration was revealed in and around the injection site: an intense area of proliferative cells, degenerating terminal axon ramifications and cell death. In comparison with electrolytic lesion, excitotoxic lesion displays important advantages, since fibres of passage are not destroyed by kainic acid injection, which induces only a restricted lesion and so is an appropriate method of investigating the role of the vertical lobe or other brain regions in a Cephalopod model, Sepia officinalis.

  11. Direct electric current treatment under physiologic saline conditions kills Staphylococcus epidermidis biofilms via electrolytic generation of hypochlorous acid.

    Directory of Open Access Journals (Sweden)

    Elizabeth L Sandvik

    Full Text Available The purpose of this study was to investigate the mechanism by which a direct electrical current reduced the viability of Staphylococcus epidermidis biofilms in conjunction with ciprofloxacin at physiologic saline conditions meant to approximate those in an infected artificial joint. Biofilms grown in CDC biofilm reactors were exposed to current for 24 hours in 1/10(th strength tryptic soy broth containing 9 g/L total NaCl. Dose-dependent log reductions up to 6.7 log(10 CFU/cm(2 were observed with the application of direct current at all four levels (0.7 to 1.8 mA/cm(2 both in the presence and absence of ciprofloxacin. There were no significant differences in log reductions for wells with ciprofloxacin compared to those without at the same current levels. When current exposures were repeated without biofilm or organics in the medium, significant generation of free chlorine was measured. Free chlorine doses equivalent to the 24 hour endpoint concentration for each current level were shown to mimic killing achieved by current application. Current exposure (1.8 mA/cm(2 in medium lacking chloride and amended with sulfate, nitrate, or phosphate as alternative electrolytes produced diminished kills of 3, 2, and 0 log reduction, respectively. Direct current also killed Pseudomonas aeruginosa biofilms when NaCl was present. Together these results indicate that electrolysis reactions generating hypochlorous acid from chloride are likely a main contributor to the efficacy of direct current application. A physiologically relevant NaCl concentration is thus a critical parameter in experimental design if direct current is to be investigated for in vivo medical applications.

  12. Direct electric current treatment under physiologic saline conditions kills Staphylococcus epidermidis biofilms via electrolytic generation of hypochlorous acid.

    Science.gov (United States)

    Sandvik, Elizabeth L; McLeod, Bruce R; Parker, Albert E; Stewart, Philip S

    2013-01-01

    The purpose of this study was to investigate the mechanism by which a direct electrical current reduced the viability of Staphylococcus epidermidis biofilms in conjunction with ciprofloxacin at physiologic saline conditions meant to approximate those in an infected artificial joint. Biofilms grown in CDC biofilm reactors were exposed to current for 24 hours in 1/10(th) strength tryptic soy broth containing 9 g/L total NaCl. Dose-dependent log reductions up to 6.7 log(10) CFU/cm(2) were observed with the application of direct current at all four levels (0.7 to 1.8 mA/cm(2)) both in the presence and absence of ciprofloxacin. There were no significant differences in log reductions for wells with ciprofloxacin compared to those without at the same current levels. When current exposures were repeated without biofilm or organics in the medium, significant generation of free chlorine was measured. Free chlorine doses equivalent to the 24 hour endpoint concentration for each current level were shown to mimic killing achieved by current application. Current exposure (1.8 mA/cm(2)) in medium lacking chloride and amended with sulfate, nitrate, or phosphate as alternative electrolytes produced diminished kills of 3, 2, and 0 log reduction, respectively. Direct current also killed Pseudomonas aeruginosa biofilms when NaCl was present. Together these results indicate that electrolysis reactions generating hypochlorous acid from chloride are likely a main contributor to the efficacy of direct current application. A physiologically relevant NaCl concentration is thus a critical parameter in experimental design if direct current is to be investigated for in vivo medical applications.

  13. Comparison of GC-MS and FTIR methods for quantifying naphthenic acids in water samples.

    Science.gov (United States)

    Scott, Angela C; Young, Rozlyn F; Fedorak, Phillip M

    2008-11-01

    The extraction of bitumen from the oil sands in Canada releases toxic naphthenic acids into the process-affected waters. The development of an ideal analytical method for quantifying naphthenic acids (general formula C(n)H(2n+Z)O(2)) has been impeded by the complexity of these mixtures and the challenges of differentiating naphthenic acids from other naturally-occurring organic acids. The oil sands industry standard FTIR method was compared with a newly-developed GC-MS method. Naphthenic acids concentrations were measured in extracts of surface and ground waters from locations within the vicinity of and away from the oil sands deposits and in extracts of process-affected waters. In all but one case, FTIR measurements of naphthenic acids concentrations were greater than those determined by GC-MS. The detection limit of the GC-MS method was 0.01 mg L(-1) compared to 1 mg L(-1) for the FTIR method. The results indicated that the GC-MS method is more selective for naphthenic acids, and that the FTIR method overestimates their concentrations.

  14. Folic acid knowledge and use among expectant mothers in 1997: a comparison with 1996.

    LENUS (Irish Health Repository)

    McDonnell, R

    1999-04-01

    This study examined changes in folic acid knowledge and use among antenatal women in Dublin maternity hospitals between 1996 and 1997, following a campaign to improve the very low uptake of peri-conceptional folic acid. The results showed significant improvements between the two years. Almost 76% of respondents had heard of folic acid in 1997 compared with 54% in 1996 (p < 0.01), with a shift in the proportion of people hearing of folic acid from hospital doctors to general practitioners (GP). Almost 43% of respondents in 1997 knew that folic acid can prevent spina bifida compared with 21% in 1996 (p < 0.01). A higher proportion was taking folic acid prior to conception in 1997 (16% vs 6%, p < 0.01). We conclude that the improvements may have been in part due to the promotional campaign among health professionals, women\\'s groups and the media. However, less than a fifth of women were taking folic acid peri-conceptionally in 1997 and there is still scope for much improvement.

  15. Comparison of inhibition effects of some benzoic acid derivatives on sheep heart carbonic anhydrase

    Science.gov (United States)

    Kiliç, Deryanur; Yildiz, Melike; Şentürk, Murat; Erdoǧan, Orhan; Küfrevioǧlu, Ömer Irfan

    2016-04-01

    Carbonic anhydrase (CA) is a family of metalloenzymes that requires Zn as a cofactor and catalyze the quick conversion of CO2 to HCO3- and H+. Inhibitors of the carbonic anhydrases (CAs) have medical usage of significant diseases such as glaucoma, epilepsy, gastroduodenal ulcers, acid-base disequilibria and neurological disorders. In the present study, inhibition of CA with some benzoic derivatives (1-6) were investigated. Sheep heart CA (shCA) enzyme was isolated by means of designed affinity chromatography gel (cellulose-benzyl-sulfanylamide) 42.45-fold in a yield of 44 % with 564.65 EU/mg. Purified shCA enzyme was used in vitro studies. In the studies, IC50 values were calculated for 3-aminobenzoic acid (1), 4-aminobenzoic acid (2), 2-hydroxybenzoic acid (3), 2-benzoylbenzoic acid (4), 2,3-dimethoxybenzoic acid (5), and 3,4,5-trimethoxybenzoic acid (6), showing the inhibition effects on the purified enzyme. Such molecules can be used as pioneer for discovery of novel effective CA inhibitors for medicinal chemistry applications.

  16. The comparison of techniques and methods for L-ascorbic acid determination in the fruits

    Directory of Open Access Journals (Sweden)

    Cvetković Biljana R.

    2012-01-01

    Full Text Available Vitamin C is an essential vitamin for human nutrition; with the L-ascorbic acid (AA being the active form of vitamin C. Hence, determination of the L-ascorbic acid in the natural and processed foods is very important. In the past, plenty of methods based on the reversible redox reaction of AA oxidation/DHA reduction were developed. Because of L-ascorbic acid instability in aqueous solutions, it is useful to analyze various types of extraction. The aim of this study is to compare three different methods and three different extractants for the L-ascorbic acid determination. Fruits (kiwi, lemon, orange, and grapefruit were purchased from a local market. The L-ascorbic acid in these four samples was determined by the three different methods: the AOAC, the HPLC method with three different types of extractions, and the colorimetric method using ascorbate-oxidase. For the HPLC measurements, one part of the fruits was extracted with distilled water, the second with potassium hydrogen phosphate, and the third with 3% meta-phosphoric acid (MPA in 8% acetic acid. The HPLC measurements of each sample were repeated three times, the AOAC titration was repeated five times, and in the calorimetric method three measurements were performed. The results were statistically evaluated related to sample basis. Statistical analysis shows that there is a significant difference between the results for all three methods of extraction for all samples, except for the grapefruit sample where no significant difference was observed between the results obtained after the buffer extraction (E2 and the metaphosphoric acid in acetic acid extraction (E3. Discriminative analysis for the HPLC determinations proves that there is a clear difference and defined border between the samples in relation to the methods of extraction during the HPLC determination.

  17. THE COMPARISON OF ACID ASCORBIC CONTENT DURING PROCESSING OF SOME VEGETABLES AND FRUITS

    Directory of Open Access Journals (Sweden)

    Marcel Avramiuc

    2015-07-01

    Full Text Available In this work there was searched the ascorbic acid content variation in four plant species during processing. The biological material was represented by: green onion, spinach leaves, pear fruits (from vegetable farms around Suceava town and kiwi fruits (from supermarket. The ascorbic acid content was determined through a method based on reduction (by the ascorbic acid of 2.6-Dichlorphenol-indophenol to the corresponding leucoderivate. Through grinding and one hour exposure to air at 20-22°C, the largest reduction in ascorbic acid content was in pear fruits (50%, and the lowest one in spinach leaves (11.7%. By means of thermal processing (boiling the ascorbic acid content of the analyzed species has changed in different proportions. Thus, as compared to fresh samples, in boiled ones the vitamin C content has decreasedmost in pear fruits (by 52.6% and least in spinach leaves (by 38.5%. Under the same conditions, in green onion samplethe ascorbic acid mean content has increased by 10.8%, compared to fresh sample. In the fruit species, under thermal processing conditions, the ascorbic acid mean content was different as against heat-unprocessed samples. Thus, at kiwi fruits both in samples poached with sugar and without sugar, the total content of ascorbic acid (from product and boiling liquid was superior to the heat-unprocessed samples. In contrast, at pear fruits, under the same experimental conditions, the total content of ascorbic acid was lower than in heat-unprocessed samples.

  18. Comparison of amino acid content in frozen P. ostreatus and A. bisporus mushrooms

    Directory of Open Access Journals (Sweden)

    Emilia Bernaś

    2010-09-01

    Full Text Available Background. The present work compares the content of basic chemical constituents as well as amino acids in frozen Pleurotus ostreatus (Jacq.: Fr. Kumm. and Agaricus bisporus (Lange Sing. mushrooms. Material and methods. The material investigated comprised of frozen P. ostreatus and A. bisporus mushrooms after 8 months’ storage, having been soaked and blanched in a solution 0.5% citric acid, 0.5% lactic acid and 0.1% L-ascorbic acid prior to freezing. Results. Compared with frozen A. bisporus, frozen P. ostreatus contained significantly higher levels of total carbohydrates (32% higher, raw fat (38% and most endogenous (6-163% and exogenous (10-200% amino acids, but lower levels of ash (45% lower, total nitrogen (50% and protein nitrogen (40%. In both species, asparagine and glutamine were the most abundant endogenous amino acids (respectively 10-12% and 12-19% of total amino acids, and leucine and lysine the most abundant exogenous amino acids (7-9% and 6-7%. The least abundant were glycine and proline (both 5%, and cysteine and methionine (1% and 2%. Conclusions. Frozen mushrooms of both species are potentially good sources of protein in the diet as no limiting amino acids were found when compared with the FAO/WHO reference protein pattern. However, it is important to determine the digestibility of protein in the mushrooms model studies using animals and people. The conversion coefficient from total nitrogen to protein was 5.23 in P. ostreatus and 2.46 in A. bisporus.

  19. Comparison of acidulated phosphate fluoride gel and hydrofluoric acid etchants for porcelain-composite repair.

    Science.gov (United States)

    Tylka, D F; Stewart, G P

    1994-08-01

    Hydrofluoric acid etches porcelain to produce a porous surface visible under scanning electron microscopy when compared to an acidulated phosphate fluoride gel. Some investigators have suggested the greater porosity of the hydrofluoric acid etch produces a greater composite-to-porcelain bond. This investigation tested that assumption with two common fluoride etchants. The etched surfaces were first viewed under scanning electron microscopy to ensure that a characteristic etch was achieved. Both etchants yielded bond strengths that produced cohesive failure of all samples. This suggested that the intraoral use of hydrofluoric acid is no more effective than the less dangerous acidulated phosphate fluoride gel.

  20. Comparison of linoleic and conjugated linoleic acids in enzymatic acidolysis of tristearin

    DEFF Research Database (Denmark)

    Yang, Tiankui; Xu, Xuebing; Li, L.T.

    2001-01-01

    The acyl incorporation and migration of linoleic and conjugated linoleic acids in enzymatic acidolysis were compared in a solvent-free system. Two systems were used in the Lipozyme RM IM-catalyzed acidolysis at 60C temperature and 5% by weight enzyme load (based on substrates). One included...... with gas chromatography, pancreatic lipase hydrolysis, and high performance liquid chromatography. Both acyl incorporation and migration of linoleic acid were faster than those of conjugated linoleic acid. At 5 h reaction, there were 13.0% LLL, 46.5% LSL, 27.7% LSS, and 5.6% SSS in the product for a system...

  1. Direct comparison of repeated soil inventory and carbon flux budget to detect soil carbon stock changes in grassland

    Science.gov (United States)

    Ammann, C.; Leifeld, J.; Neftel, A.; Fuhrer, J.

    2012-04-01

    Experimental assessment of soil carbon (C) stock changes over time is typically based on the application of either one of two methods, namely (i) repeated soil inventory and (ii) determination of the ecosystem C budget or net biome productivity (NBP) by continuous measurement of CO2 exchange in combination with quantification of other C imports and exports. However, there exist hardly any published study hitherto that directly compared the results of both methods. Here, we applied both methods in parallel to determine C stock changes of two temperate grassland fields previously converted from long-term cropland. The grasslands differed in management intensity with either intensive management (high fertilization, frequent cutting) or extensive management (no fertilization, less frequent cutting). Soil organic C stocks (0-45 cm depth) were quantified at the beginning (2001) and the end (2006) of a 5 year observational period using the equivalent soil mass approach. For the same period and in both fields, NBP was quantified from net CO2 fluxes monitored using eddy covariance systems, and measured C import by organic fertilizer and C export by harvest. Both NBP and repeated soil inventories revealed a consistent and significant difference between management systems of 170 ± 48 and 253 ± 182 g C m-2 a-1, respectively. For both fields, the inventory method showed a tendency towards higher C loss/smaller C gain than NBP. In the extensive field, a significant C loss was observed by the inventory but not by the NBP approach. Thus both, flux measurements and repeated soil sampling, seem to be adequate and equally suited for detecting relative management effects. However, the suitability for tracking absolute changes in SOC could not be proven for neither of the two methods. Overall, our findings stress the need for more direct comparisons to evaluate whether the observed difference in the outcome of the two approaches reflects a general methodological bias, which would

  2. Corona-directed nucleic acid delivery into hepatic stellate cells for liver fibrosis therapy.

    Science.gov (United States)

    Zhang, Zhengping; Wang, Chunming; Zha, Yinhe; Hu, Wei; Gao, Zhongfei; Zang, Yuhui; Chen, Jiangning; Zhang, Junfeng; Dong, Lei

    2015-03-24

    Strategies to modify nanoparticles with biological ligands for targeted drug delivery in vivo have been widely studied but met with limited clinical success. A possible reason is that, in the blood circulation, serum proteins could rapidly form a layer of protein "corona" on the vehicle surface, which might block the modified ligands and hamper their targeting functions. We speculate that strategies for drug delivery can be designed based upon elegant control of the corona formation on the vehicle surfaces. In this study, we demonstrate a retinol-conjugated polyetherimine (RcP) nanoparticle system that selectively recruited the retinol binding protein 4 (RBP) in its corona components. RBP was found to bind retinol, and direct the antisense oligonucleotide (ASO)-laden RcP carrier to hepatic stellate cells (HSC), which play essential roles in the progression of hepatic fibrosis. In both mouse fibrosis models, induced by carbon tetrachloride (CCl4) and bile duct ligation (BDL), respectively, the ASO-laden RcP particles effectively suppressed the expression of type I collagen (collagen I), and consequently ameliorated hepatic fibrosis. Such findings suggest that this delivery system, designed to exploit the power of corona proteins, can serve as a promising tool for targeted delivery of therapeutic agents for the treatment of hepatic fibrosis.

  3. Global trophic position comparison of two dominant mesopelagic fish families (Myctophidae, Stomiidae) using amino acid nitrogen isotopic analyses

    Science.gov (United States)

    Choy, C. Anela; Davison, Peter C.; Drazen, Jeffrey C.; Flynn, Adrian; Gier, Elizabeth J.; Hoffman, Joel C.; McClain-Counts, Jennifer P.; Miller, Todd W.; Popp, Brian N.; Ross, Steve W.; Sutton, Tracey T.

    2012-01-01

    The δ15N values of organisms are commonly used across diverse ecosystems to estimate trophic position and infer trophic connectivity. We undertook a novel cross-basin comparison of trophic position in two ecologically well-characterized and different groups of dominant mid-water fish consumers using amino acid nitrogen isotope compositions. We found that trophic positions estimated from the δ15N values of individual amino acids are nearly uniform within both families of these fishes across five global regions despite great variability in bulk tissue δ15N values. Regional differences in the δ15N values of phenylalanine confirmed that bulk tissue δ15N values reflect region-specific water mass biogeochemistry controlling δ15N values at the base of the food web. Trophic positions calculated from amino acid isotopic analyses (AA-TP) for lanternfishes (family Myctophidae) (AA-TP ~2.9) largely align with expectations from stomach content studies (TP ~3.2), while AA-TPs for dragonfishes (family Stomiidae) (AA-TP ~3.2) were lower than TPs derived from stomach content studies (TP~4.1). We demonstrate that amino acid nitrogen isotope analysis can overcome shortcomings of bulk tissue isotope analysis across biogeochemically distinct systems to provide globally comparative information regarding marine food web structure.

  4. Comparison of fumaric acid 5% cream versus triamcinolone 0.1% cream in the treatment of hand eczema.

    Directory of Open Access Journals (Sweden)

    Farideh Jowkar

    2014-07-01

    Full Text Available Hand eczema is a common distressing skin problem. It is an immune reaction to haptens. Thus, substances that inhibit Immune system can be effective in the treatment of hand eczema. In this study, topical fumaric acid 5% cream is compared with topical steroid in the treatment of hand eczema. Patients with hand eczema were randomly divided into two groups. One group received fumaric acid 5% in a cream base, and the other received triamcinolone 0.1% in the same cream base. Both groups used creams twice daily for one month. Patients were checked for erythema, excoriation, population and lichenification, EASI score, and pruritus before and after treatment. In both groups, the mean of all signs of the disease and EASI score decreased after one month of treatment. There was no significant difference between the two treatments in decreasing erythema, but excoriation, population, lichenification, EASI score and itching were all decreased more in triamcinolone 0.1 % group. Although fumaric acid can inhibit the immune system; it was less effective for the treatment of all signs of hand eczema except erythema in comparison to triamcinolone. These results may be justified for two reasons: low penetration of topical fumaric acid through the skin or a low concentration used in this study.

  5. Comparison of fumaric acid 5% cream versus triamcinolone 0.1% cream in the treatment of hand eczema.

    Science.gov (United States)

    Jowkar, Farideh; Saki, Nasrin; Mokhtarpour, Akbar; Saki, Mohammad Reza

    2014-01-01

    Hand eczema is a common distressing skin problem. It is an immune reaction to haptens. Thus, substances that inhibit Immune system can be effective in the treatment of hand eczema. In this study, topical fumaric acid 5% cream is compared with topical steroid in the treatment of hand eczema. Patients with hand eczema were randomly divided into two groups. One group received fumaric acid 5% in a cream base, and the other received triamcinolone 0.1% in the same cream base. Both groups used creams twice daily for one month. Patients were checked for erythema, excoriation, population and lichenification, EASI score, and pruritus before and after treatment. In both groups, the mean of all signs of the disease and EASI score decreased after one month of treatment. There was no significant difference between the two treatments in decreasing erythema, but excoriation, population, lichenification, EASI score and itching were all decreased more in triamcinolone 0.1 % group. Although fumaric acid can inhibit the immune system; it was less effective for the treatment of all signs of hand eczema except erythema in comparison to triamcinolone. These results may be justified for two reasons: low penetration of topical fumaric acid through the skin or a low concentration used in this study.

  6. Global trophic position comparison of two dominant mesopelagic fish families (Myctophidae, Stomiidae using amino acid nitrogen isotopic analyses.

    Directory of Open Access Journals (Sweden)

    C Anela Choy

    Full Text Available The δ(15N values of organisms are commonly used across diverse ecosystems to estimate trophic position and infer trophic connectivity. We undertook a novel cross-basin comparison of trophic position in two ecologically well-characterized and different groups of dominant mid-water fish consumers using amino acid nitrogen isotope compositions. We found that trophic positions estimated from the δ(15N values of individual amino acids are nearly uniform within both families of these fishes across five global regions despite great variability in bulk tissue δ(15N values. Regional differences in the δ(15N values of phenylalanine confirmed that bulk tissue δ(15N values reflect region-specific water mass biogeochemistry controlling δ(15N values at the base of the food web. Trophic positions calculated from amino acid isotopic analyses (AA-TP for lanternfishes (family Myctophidae (AA-TP ∼2.9 largely align with expectations from stomach content studies (TP ∼3.2, while AA-TPs for dragonfishes (family Stomiidae (AA-TP ∼3.2 were lower than TPs derived from stomach content studies (TP∼4.1. We demonstrate that amino acid nitrogen isotope analysis can overcome shortcomings of bulk tissue isotope analysis across biogeochemically distinct systems to provide globally comparative information regarding marine food web structure.

  7. Smooth and Clumpy Dust Distribution in AGN: a Direct Comparison of two Commonly Explored Infrared Emission Models

    CERN Document Server

    Feltre, A; Fritz, J; Franceschini, A

    2012-01-01

    The geometry of the dust distribution within the inner regions of Active Galactic Nuclei (AGN) is still a debated issue and relates directly with the AGN unified scheme. Traditionally, models discussed in the literature assume one of two distinct dust distributions in what is believed to be a toroidal region around the Supermassive Black Holes: a continuous distribution, customarily referred to as smooth, and a concentration of dust in clumps or clouds, referred to as clumpy. In this paper we perform a thorough comparison between two of the most popular models in the literature, namely the smooth models by Fritz. et al. 2006 and the clumpy models by Nenkova et al. 2008a, in their common parameters space. Particular attention is paid to the silicate features at ~9.7 and ~18 micron, the width of the infrared bump, the near-infrared index and the luminosity at 12.3 micron, all previously reported as possible diagnostic tools to distinguish between the two dust distributions. We find that, due to the different du...

  8. A Bioequivalence Test by the Direct Comparison of Concentration-versus-Time Curves Using Local Polynomial Smoothers

    Science.gov (United States)

    Chang, Howard H.; Orange, Dana

    2016-01-01

    In order to test if two chemically or pharmaceutically equivalent products have the same efficacy and/or toxicity, a bioequivalence (BE) study is conducted. The 80%/125% rule is the most commonly used criteria for BE and states that BE cannot be claimed unless the 90% CIs for the ratio of selected pharmacokinetics (PK) parameters of the tested to the reference drug are within 0.8 to 1.25. Considering that estimates of these PK parameters are derived from the concentration-versus-time curves, a direct comparison between these curves motivates an alternative and more flexible approach to test BE. Here, we propose to frame the BE test in terms of an equivalence of concentration-versus-time curves which are constructed using local polynomial smoother (LPS). A metric is presented to quantify the distance between the curves and its 90% CIs are calculated via bootstrapping. Then, we applied the proposed procedures to data from an animal study and found that BE between a generic drug and its brand name cannot be concluded, which was consistent with the results by applying the 80%/125% rule. However, the proposed procedure has the advantage of testing only on a single metric, instead of all PK parameters. PMID:28050196

  9. Direct simulation of electron transfer using ring polymer molecular dynamics: comparison with semiclassical instanton theory and exact quantum methods.

    Science.gov (United States)

    Menzeleev, Artur R; Ananth, Nandini; Miller, Thomas F

    2011-08-21

    The use of ring polymer molecular dynamics (RPMD) for the direct simulation of electron transfer (ET) reaction dynamics is analyzed in the context of Marcus theory, semiclassical instanton theory, and exact quantum dynamics approaches. For both fully atomistic and system-bath representations of condensed-phase ET, we demonstrate that RPMD accurately predicts both ET reaction rates and mechanisms throughout the normal and activationless regimes of the thermodynamic driving force. Analysis of the ensemble of reactive RPMD trajectories reveals the solvent reorganization mechanism for ET that is anticipated in the Marcus rate theory, and the accuracy of the RPMD rate calculation is understood in terms of its exact description of statistical fluctuations and its formal connection to semiclassical instanton theory for deep-tunneling processes. In the inverted regime of the thermodynamic driving force, neither RPMD nor a related formulation of semiclassical instanton theory capture the characteristic turnover in the reaction rate; comparison with exact quantum dynamics simulations reveals that these methods provide inadequate quantization of the real-time electronic-state dynamics in the inverted regime.

  10. Blue Straggler Stars a direct comparison of Star counts and population ratios in six Galactic Globular Clusters

    CERN Document Server

    Ferraro, F R; Rood, R T; Paltrinieri, B; Buonanno, R; Ferraro, Francesco R.; Sills, Alison; Rood, Robert T.; Paltrinieri, Barbara; Buonanno, Roberto

    2003-01-01

    The central regions of six Galactic Globular Clusters (GGCs) (M3, M80, M10, M13, M92 and NGC 288) have been imaged using HST-WFPC2 and the ultraviolet (UV) filters (F255W, F336W). The selected sample covers a large range in both central density and metallicity ([Fe/H]). In this paper, we present a direct cluster-to-cluster comparison of the Blue Stragglers Stars (BSS) population as selected from (m_{255},m_{255}-m_{336}) Color Magnitude Diagrams (CMDs). We have found:(a) BSS in three of the clusters (M3, M80, M92) are much more concentrated toward the center of the cluster than the red giants; because of the smaller BSS samples for the other clusters we can only note that the BSS radial distributions are consistent with central concentration; (b) the specific frequency of BSS varies greatly from cluster to cluster. The most interesting result is that the two clusters with largest BSS specific frequency are at the central density extremes of our sample: NGC 288 (lowest central density) and M80 (highest). This ...

  11. Comparison of epoxy- and siloxane-based single-mode optical waveguides defined by direct-write lithography

    Science.gov (United States)

    Elmogi, Ahmed; Bosman, Erwin; Missinne, Jeroen; Van Steenberge, Geert

    2016-02-01

    This paper reports on the fabrication and characterization of single-mode polymer optical waveguides at telecom and SOI compatible wavelengths; by making a comparison between an epoxy and a siloxane polymer waveguide material system (both commercially-available). The proposed waveguides can be used in short-reach optical interconnects targeting chip-to-chip communication on the interposer level or providing a coupling interface between single-mode optical fibers and photonic integrated circuits (PICs). This technology enables the integration of optoelectronic chips for photonic packaging purposes. First, the single-mode dimensions (4 × 4 μm2 and 5 × 5 μm2) for both materials at selected wavelengths (1.31 μm and 1.55 μm) were determined based on the refractive index measurements. Then, the waveguides were patterned by a direct-write lithography method. The fabricated waveguides show a high-quality surface with smooth sidewalls. The optical propagation losses were measured using the cut-back method. For the siloxane-based waveguides, the propagation losses were found to be 0.34 dB/cm and 1.36 dB/cm at 1.31 μm and 1.55 μm respectively while for the epoxy-based waveguides the losses were 0.49 dB/cm and 2.23 dB/cm at 1.31 μm and 1.55 μm respectively.

  12. Revisiting AI-2 quorum sensing inhibitors: direct comparison of alkyl-DPD analogues and a natural product fimbrolide.

    Science.gov (United States)

    Lowery, Colin A; Abe, Takumi; Park, Junguk; Eubanks, Lisa M; Sawada, Daisuke; Kaufmann, Gunnar F; Janda, Kim D

    2009-11-04

    Quorum sensing (QS) systems have been discovered in a wide variety of bacteria, and mediate both intra- and interspecies communication. The AI-2-based QS system represents the most studied of these proposed interspecies systems and has been shown to regulate diverse functions such as bioluminescence, expression of virulence factors, and biofilm formation. As such, the development of modulatory compounds, both agonists and antagonists, is of great interest for the study of unknown AI-2-based QS systems and the potential treatment of bacterial infections. The fimbrolide class of natural products has exhibited excellent inhibitory activity against AI-2-based QS and as such may be considered the "gold standard" of AI-2 inhibitors. Thus, we sought to include a fimbrolide as a control compound for our recently developed alkyl-DPD panel of AI-2 modulators. Herein, we present a revised synthesis of a commonly studied fimbrolide as well as a direct comparison between the fimbrolide and alkyl-DPD analogues. We demonstrate that our alkyl-DPD analogues are more potent inhibitors of QS in both Vibrio harveyi and Salmonella typhimurium, the two organisms with defined AI-2 QS systems, and in doing so call into question the widely accepted use of fimbrolide-derived compounds as the "gold standard" of AI-2 inhibition.

  13. Comparison of dilute mineral and organic acid pretreatment for enzymatic hydrolysis of wheat straw

    NARCIS (Netherlands)

    Kootstra, A.M.J.; Beeftink, H.H.; Scott, E.L.; Sanders, J.P.M.

    2009-01-01

    The efficiencies of fumaric, maleic, and sulfuric acid in wheat straw pretreatment were compared. As a measure for pretreatment efficiency, enzymatic digestibility of the lignocellulose was determined. Monomeric glucose and xylose concentrations were measured after subsequent enzymatic hydrolysis, a

  14. Comparison of Cultivable Acetic Acid Bacterial Microbiota in Organic and Conventional Apple Cider Vinegar

    OpenAIRE

    2016-01-01

    Organic apple cider vinegar is produced from apples that go through very restricted treatment in orchard. During the first stage of the process, the sugars from apples are fermented by yeasts to cider. The produced ethanol is used as a substrate by acetic acid bacteria in a second separated bioprocess. In both, the organic and conventional apple cider vinegars the ethanol oxidation to acetic acid is initiated by native microbiota that survived alcohol fermentation. We compared the cultivable ...

  15. Effects of social comparison direction, threat, and self-esteem on affect, self-evaluation, and expected success.

    Science.gov (United States)

    Aspinwall, L G; Taylor, S E

    1993-05-01

    Two studies explored the conditions under which social comparisons are used to manage negative affect and naturalistic threats. Study 1 examined induced mood and dispositional self-esteem as determinants of affective responses to upward and downward comparisons. Consistent with a mood repair prediction, only low-self-esteem Ss in whom a negative mood had been induced reported improved mood after exposure to downward comparison information. Study 2 examined the impact of naturalistic threats on responses to comparison information. Relative to a no-comparison baseline, low-self-esteem Ss who had experienced a recent academic setback reported more favorable self-evaluations and greater expectations of future success in college after exposure to downward comparison information. These results remained significant after controlling statistically for general distress. Implications for downward comparison theory are discussed.

  16. A comparison of neutralization efficiency of chemicals with respect to acidic Kopili River water

    Science.gov (United States)

    Kapil, Nibedita; Bhattacharyya, Krishna G.

    2016-02-01

    Among all the renewable sources of energy, hydropower is the most potential source which is economical, non-polluting and eco-friendly. The efficiency of hydropower plant in the long run depends on many factors like water and sediment quality. Erosive and corrosive wear of machine parts like turbine is a complex phenomenon. The problem becomes more acute if the hydroenvironment is acidic in nature. The wear and tear due to corrosion/erosion caused by acid mine drainage (AMD) from coal mines reduces the efficiency and the life of the equipments. In this work, neutralization of the acidic water of the Kopili River, Assam, India was investigated using a number of basic chemicals and quantitatively estimating their effectiveness and actual requirement. The acidic water of the river, used as the cooling water, has been found responsible for damaging the equipments of the Kopili Hydro Electric Power Project (KHEP), Assam/Meghalaya, India by reducing the life of all metallic parts through corrosion. In this work, use is made of a number of basic materials like calcium carbonate, calcium hydroxide, calcium oxide, sodium carbonate, sodium hydroxide, and ammonia to examine their neutralization efficiency with respect to the acidic water and it was found that quick lime or raw lime (CaO) has the highest neutralization capacity. Suggestions have been made for meeting the problem of acidity of the river water.

  17. Comparison of Butyric acid concentrations in ordinary and probiotic yogurt samples in Iran

    Directory of Open Access Journals (Sweden)

    Narges Vaseji

    2012-06-01

    Full Text Available Background and objectives: Butyric acid has many applications in chemical, food and pharmaceutical industries. Applications of butyric acid are as an additive to food, flavorings, varnishes, perfumes, pharmaceuticals and disinfectants. Butyric acid concentrations have positive impact on the quality control of milk, yogurt and other probiotic dairy products. The present investigation was undertaken to determine and compare the concentrations of butyric acid (C4 in the ordinary and probiotic yogurt samples by GC method.Materials and Methods: Probiotic yogurt samples were prepared under laboratory scale conditions using two different commercial starters ABY1 and 211, while ordinary yogurt samples lacked the probiotic starter cultures. All samples were analyzed in duplicate, for C4 concentrations by gas chromatography after day 1, 2, 10 and 20 of production, during storage at 4ºC. The results were analyzed using ANOVA and Duncan test.Results: The level of the mentioned fatty acid in ABY1 yogurt sample was significantly higher (0.2% than in 211 samples (0.17%. These values were significantly lower in ordinary yogurt samples and only 0.07% was recorded in these samples on first day of storage which decreased gradually during storage. The level of reduction in the yogurt samples tested during different time intervals was not similar in all the examined samples, and some showed enhanced reduction than other samples.Conclusions: Compared to ordinary yogurt samples, probiotic yogurt samples used in study showed higher levels of butyric acid with increased shelf life.

  18. Comparison of Fatty Acid and Cholesterol Content of Pakistani Water Buffalo Breeds

    Directory of Open Access Journals (Sweden)

    M. I. Bhanger

    2007-12-01

    Full Text Available Present study evaluates the milk fatty acid (FA composition and cholesterol content of two main Pakistani dairy breeds water buffaloes, i.e. Kundi and Nili-Ravi (n = 25 for each breed. The buffaloes were housed together and received the same diet. The results show a significant variation (P < 0.05 in the FA content of the two breeds. The milk fat of Kundi buffalo was found to contain significantly lower (P < 0.05 amount of saturated fatty acid content than Nili-Ravi buffaloes (66.96 and 69.09 g/100 g. Determined mean monounsaturated fatty acid (MUFA contents (27.62 vs. 25.20 g/100g and total trans fatty acids (3.48 vs. 2.48 were significantly elevated (P < 0.05 in the milk fat of Kundi buffaloes. Amount of fat and conjugated linoleic acid content was higher (P = 0.04 in Kundi buffalo as compared to Nili-Ravi buffaloes (7.00 vs. 7.78 g /100g and 0.80 vs. 0.71g / 100g, while cholesterol content was not different among both breeds ranging from 8.89 – 10.24 mg /dl. Present studies show that in future genetic selection programs along with altered buffalo nutrition may be able to result in optimum levels of various fatty acids in milk.

  19. A Complex Prime Numerical Representation of Amino Acids for Protein Function Comparison.

    Science.gov (United States)

    Chen, Duo; Wang, Jiasong; Yan, Ming; Bao, Forrest Sheng

    2016-08-01

    Computationally assessing the functional similarity between proteins is an important task of bioinformatics research. It can help molecular biologists transfer knowledge on certain proteins to others and hence reduce the amount of tedious and costly benchwork. Representation of amino acids, the building blocks of proteins, plays an important role in achieving this goal. Compared with symbolic representation, representing amino acids numerically can expand our ability to analyze proteins, including comparing the functional similarity of them. Among the state-of-the-art methods, electro-ion interaction pseudopotential (EIIP) is widely adopted for the numerical representation of amino acids. However, it could suffer from degeneracy that two different amino acid sequences have the same numerical representation, due to the design of EIIP. In light of this challenge, we propose a complex prime numerical representation (CPNR) of amino acids, inspired by the similarity between a pattern among prime numbers and the number of codons of amino acids. To empirically assess the effectiveness of the proposed method, we compare CPNR against EIIP. Experimental results demonstrate that the proposed method CPNR always achieves better performance than EIIP. We also develop a framework to combine the advantages of CPNR and EIIP, which enables us to improve the performance and study the unique characteristics of different representations.

  20. Comparison of sulfuric and hydrochloric acids as catalysts in hydrolysis of Kappaphycus alvarezii (cottonii).

    Science.gov (United States)

    Meinita, Maria Dyah Nur; Hong, Yong-Ki; Jeong, Gwi-Taek

    2012-01-01

    In this study, hydrolysis of marine algal biomass Kappaphhycus alvarezii using two different acid catalysts was examined with the goal of identifying optimal reaction conditions for the formation of sugars and by-products. K. alvarezii were hydrolyzed by autoclave using sulfuric acid or hydrochloric acid as catalyst with different acid concentrations (0.1-1.0 M), substrate concentrations (1.0-13.5%), hydrolysis time (10-90 min) and hydrolysis temperatures (100-130 (°)C). A difference in galactose, glucose, reducing sugar and total sugar content was observed under the different hydrolysis conditions. Different by-product compounds such as 5-hydroxymethylfurfural and levulinic acid were also observed under the different reaction conditions. The optimal conditions for hydrolysis were achieved at a sulfuric acid concentration, temperature and reaction time of 0.2 M, 130 °C and 15 min, respectively. These results may provide useful information for the development of more efficient systems for biofuel production from marine biomass.

  1. [Anti-inflammatory effect of Urtica dioica folia extract in comparison to caffeic malic acid].

    Science.gov (United States)

    Obertreis, B; Giller, K; Teucher, T; Behnke, B; Schmitz, H

    1996-01-01

    Urtica dioica extract is a traditionary used adjuvant therapeutic in rheumatoid arthritis. The antiphlogistic effects of the urtica dioica folia extract IDS 23 (Extractum Urticae dioicae foliorum) and the main phenolic ingredient caffeic malic acid were tested concerning the inhibitory potential on biosynthesis of arachidonic acid metabolites in vitro. The caffeic malic acid was isolated from Urtica folia extract using gel exclusion- and high performance liquid chromatography and identified by mass spectroscopy and nuclear magnetic resonance. Concerning the 5-lipoxygenase products IDS 23 showed a partial inhibitory effect. The isolated phenolic acid inhibited the synthesis of the leukotriene B4 in a concentration dependent manner. The concentration for halfmaximal inhibition (IC50) was 83 microns/ml in the used assay. IDS 23 showed a strong concentration dependent inhibition of the synthesis of cyclooxygenase derived reactions. The IC50 were 92 micrograms/ml for IDS 23 and 38 micrograms/ml for the caffeic malic acid. Calculating the content in IDS 23 the caffeic malic acid is a possible but not the only active ingredient of the plant extract in the tested assay systems. It is demonstrated that the phenolic component showed a different enzymatic target compared with IDS 23. The antiphlogistic effects observed in vitro may give an explanation for the pharmacological and clinical effects of IDS 23 in therapie of rheumatoid diseases.

  2. Mass spectrometry of planetary exospheres at high relative velocity: direct comparison of open- and closed source measurements

    Science.gov (United States)

    Meyer, Stefan; Tulej, Marek; Wurz, Peter

    2016-04-01

    The exploration of habitable worlds around the gas giants in the Solar System is of major interest in upcoming planetary missions. Exactly this theme is addressed by the Jupiter Icy Moons Explorer (JUICE) mission of ESA, which will characterise Ganymede, Europa and Callisto as planetary objects and potential habitats [1], [2]. We developed a prototype of the Neutral gas and Ion Mass spectrometer (NIM) of the Particle Environment Package (PEP) for the JUICE mission intended for composition measurements of neutral gas and thermal plasma. NIM/PEP will be used to measure the chemical composition of the exospheres of the icy Jovian moons. Besides direct ion measurement, the NIM instrument is able to measure the inflowing neutral gas in two different modes: in neutral mode the gas enters directly the ion source (open source) and in thermal mode, the gas gets thermally accommodated to wall temperature by several collisions inside an equilibrium sphere before entering the ion source (closed source). We performed measurements with the prototype NIM using a neutral gas beam of 1 up to 5 km/s velocity in the neutral and thermal mode. The current trajectory of JUICE foresees a flyby velocity of 4 km/s at Europa, other flybys are in the range of 1 up to 7 km/s and velocity in Ganymede orbits is around 2 km/s. Different species are used for gas beam, such as noble gases Ne, Ar, Kr as well as molecules like H2, Methane, Ethane, Propane and more complex ones. We will present the results of these measurements with respect to fragmentation and density enhancements in the closed source mode. Furthermore, we will give a direct comparison between open and closed source mode measurements. References: [1] ESA, "JUICE assessment study report (Yellow Book)", ESA/SRE(2011)18, 2012. [2] O. Grasset, M.K. Dougherty, A. Coustenis, E.J. Bunce, C. Erd, D. Titov, M. Blanc, A. Coates, P. Drossart, L.N. Fletcher, H. Hussmann, R. Jaumann, N. Krupp, J.-P. Lebreton, O. Prieto-Ballesteros, P. Tortora, F

  3. Notch stimulates growth by direct regulation of genes involved in the control of glycolysis and the tricarboxylic acid cycle.

    Science.gov (United States)

    Slaninova, Vera; Krafcikova, Michaela; Perez-Gomez, Raquel; Steffal, Pavel; Trantirek, Lukas; Bray, Sarah J; Krejci, Alena

    2016-02-01

    Glycolytic shift is a characteristic feature of rapidly proliferating cells, such as cells during development and during immune response or cancer cells, as well as of stem cells. It results in increased glycolysis uncoupled from mitochondrial respiration, also known as the Warburg effect. Notch signalling is active in contexts where cells undergo glycolytic shift. We decided to test whether metabolic genes are direct transcriptional targets of Notch signalling and whether upregulation of metabolic genes can help Notch to induce tissue growth under physiological conditions and in conditions of Notch-induced hyperplasia. We show that genes mediating cellular metabolic changes towards the Warburg effect are direct transcriptional targets of Notch signalling. They include genes encoding proteins involved in glucose uptake, glycolysis, lactate to pyruvate conversion and repression of the tricarboxylic acid cycle. The direct transcriptional upregulation of metabolic genes is PI3K/Akt independent and occurs not only in cells with overactivated Notch but also in cells with endogenous levels of Notch signalling and in vivo. Even a short pulse of Notch activity is able to elicit long-lasting metabolic changes resembling the Warburg effect. Loss of Notch signalling in Drosophila wing discs as well as in human microvascular cells leads to downregulation of glycolytic genes. Notch-driven tissue overgrowth can be rescued by downregulation of genes for glucose metabolism. Notch activity is able to support growth of wing during nutrient-deprivation conditions, independent of the growth of the rest of the body. Notch is active in situations that involve metabolic reprogramming, and the direct regulation of metabolic genes may be a common mechanism that helps Notch to exert its effects in target tissues.

  4. Comparison of trichostatin A and valproic acid treatment regimens in a mouse model of kidney fibrosis

    Energy Technology Data Exchange (ETDEWEB)

    Van Beneden, Katrien, E-mail: kvbenede@vub.ac.be [Department of Human Anatomy, Liver Cell Biology Lab, Vrije Universiteit Brussel, Brussels (Belgium); Geers, Caroline [Department of Pathology, Universitair Ziekenhuis Brussel, Brussels (Belgium); Pauwels, Marina [Department of Human Anatomy, Liver Cell Biology Lab, Vrije Universiteit Brussel, Brussels (Belgium); Mannaerts, Inge [Department of Cell Biology, Liver Cell Biology Lab, Vrije Universiteit Brussel, Brussels (Belgium); Wissing, Karl M. [Department of Nephrology, Universitair Ziekenhuis Brussel, Brussels (Belgium); Van den Branden, Christiane [Department of Human Anatomy, Liver Cell Biology Lab, Vrije Universiteit Brussel, Brussels (Belgium); Grunsven, Leo A. van, E-mail: lvgrunsv@vub.ac.be [Department of Cell Biology, Liver Cell Biology Lab, Vrije Universiteit Brussel, Brussels (Belgium)

    2013-09-01

    Histone deacetylase (HDAC) inhibitors are promising new compounds for the therapy of fibrotic diseases. In this study we compared the effect of two HDAC inhibitors, trichostatin A and valproic acid, in an experimental model of kidney fibrosis. In mice, doxorubicin (adriamycin) can cause nephropathy characterized by chronic proteinuria, glomerular damage and interstitial inflammation and fibrosis, as seen in human focal segmental glomerulosclerosis. Two treatment regimens were applied, treatment was either started prior to the doxorubicin insult or delayed until a significant degree of proteinuria and fibrosis was present. Pre-treatment of trichostatin A significantly hampered glomerulosclerosis and tubulointerstitial fibrosis, as did the pre-treatment with valproic acid. In contrast, the development of proteinuria was only completely inhibited in the pre-treated valproic acid group, and not in the pre-treated trichostatin A animals. In the postponed treatment with valproic acid, a complete resolution of established doxorubicin-induced proteinuria was achieved within three days, whereas trichostatin A could not correct proteinuria in such a treatment regimen. However, both postponed regimens have comparable efficacy in maintaining the kidney fibrosis to the level reached at the start of the treatments. Moreover, not only the process of fibrosis, but also renal inflammation was attenuated by both HDAC inhibitors. Our data confirm a role for HDACs in renal fibrogenesis and point towards a therapeutic potential for HDAC inhibitors. The effect on renal disease progression and manifestation can however be different for individual HDAC inhibitors. - Highlights: • Valproic acid is a potent antiproteinuric drug, whereas trichostatin A is not. • Trichostatin A and valproic acid reduce kidney fibrosis in doxorubicin nephropathy. • Both valproic acid and trichostatin A attenuate renal inflammation.

  5. Clavulanic acid induces penile erection and yawning in male rats: comparison with apomorphine.

    Science.gov (United States)

    Sanna, Fabrizio; Melis, Maria Rosaria; Angioni, Laura; Argiolas, Antonio

    2013-02-01

    The beta-lactamase inhibitor clavulanic acid induced penile erection and yawning in a dose dependent manner when given intraperitoneally (IP, 0.05-5mg/kg), perorally (OS, 0.1-5mg/kg) and intracereboventricularly (ICV, 0.01-5 μg/rat) to male rats. The effect resembles that of the dopamine receptor agonist apomorphine given subcutaneously (SC) (0.02-0.25mg/kg), although the responses of the latter followed a U inverted dose-response curve, disappearing at doses higher than 0.1mg/kg. Clavulanic acid responses were reduced by about 55% by haloperidol, a dopamine D2 receptor antagonist (0.1mg/kg IP), and by d(CH(2))(5)Tyr(Me)(2)-Orn(8)-vasotocin, an oxytocin receptor antagonist (2 μg/rat ICV), both given 15 min before clavulanic acid. A higher reduction of clavulanic acid responses (more than 80%) was also found with morphine, an opioid receptor agonist (5mg/kg IP), and with mianserin, a serotonin 5HT(2c) receptor antagonist (0.2mg/kg SC). In contrast, no reduction was found with naloxone, an opioid receptor antagonist (1mg/kg IP). The ability of haloperidol, d(CH(2))(5)Tyr(Me)(2)-Orn(8)-vasotocin and morphine to reduce clavulanic acid induced penile erection and yawning suggests that clavulanic acid induces these responses, at least in part, by increasing central dopaminergic neurotransmission. Dopamine in turn activates oxytocinergic neurotransmission and centrally released oxytocin induces penile erection and yawning. However, since both penile erection and yawning episodes were reduced not only by the blockade of central dopamine and oxytocin receptors and by the stimulation of opioid receptors, which inhibits oxytocinergic neurotransmission, but also by mianserin, an increase of central serotonin neurotransmission is also likely to participate in these clavulanic acid responses.

  6. Comparison of the SAWNUC model with CLOUD measurements of sulphuric acid-water nucleation

    Science.gov (United States)

    Ehrhart, Sebastian; Ickes, Luisa; Almeida, Joao; Amorim, Antonio; Barmet, Peter; Bianchi, Federico; Dommen, Josef; Dunne, Eimear M.; Duplissy, Jonathan; Franchin, Alessandro; Kangasluoma, Juha; Kirkby, Jasper; Kürten, Andreas; Kupc, Agnieszka; Lehtipalo, Katrianne; Nieminen, Tuomo; Riccobono, Francesco; Rondo, Linda; Schobesberger, Siegfried; Steiner, Gerhard; Tomé, António; Wimmer, Daniela; Baltensperger, Urs; Wagner, Paul E.; Curtius, Joachim

    2016-10-01

    Binary nucleation of sulphuric acid-water particles is expected to be an important process in the free troposphere at low temperatures. SAWNUC (Sulphuric Acid Water Nucleation) is a model of binary nucleation that is based on laboratory measurements of the binding energies of sulphuric acid and water in charged and neutral clusters. Predictions of SAWNUC are compared for the first time comprehensively with experimental binary nucleation data from the CLOUD chamber at European Organization for Nuclear Research. The experimental measurements span a temperature range of 208-292 K, sulphuric acid concentrations from 1·106 to 1·109 cm-3, and distinguish between ion-induced and neutral nucleation. Good agreement, within a factor of 5, is found between the experimental and modeled formation rates for ion-induced nucleation at 278 K and below and for neutral nucleation at 208 and 223 K. Differences at warm temperatures are attributed to ammonia contamination which was indicated by the presence of ammonia-sulphuric acid clusters, detected by an Atmospheric Pressure Interface Time of Flight (APi-TOF) mass spectrometer. APi-TOF measurements of the sulphuric acid ion cluster distributions ((H2SO4)i·HSO4- with i = 0, 1, ..., 10) show qualitative agreement with the SAWNUC ion cluster distributions. Remaining differences between the measured and modeled distributions are most likely due to fragmentation in the APi-TOF. The CLOUD results are in good agreement with previously measured cluster binding energies and show the SAWNUC model to be a good representation of ion-induced and neutral binary nucleation of sulphuric acid-water clusters in the middle and upper troposphere.

  7. The Effect of Educational Modules Strategy on the Direct and Postponed Study's Achievement of Seventh Primary Grade Students in Science, in Comparison with the Conventional Approach

    Science.gov (United States)

    Alelaimat, Abeer Rashed; Ghoneem, Khowla Abd Al Raheem

    2012-01-01

    This study aimed at revealing the effect of educational modules strategy on the direct and postponed study's achievement of seventh primary grade students in science, in comparison with the conventional approach. The sample of the study consists of (174) male and female students randomly chosen from schools in the city of Mafraq, students are…

  8. A direct in situ fingerprinting method for acid rock drainage using voltammetric techniques with a single renewable gold microelectrode.

    Science.gov (United States)

    Nuzzio, Donald B; Zettler, Erik R; Aguilera, Angeles; Amaral-Zettler, Linda A

    2011-04-15

    Electrochemistry allows for rapid identification of multiple metals and other chemical complexes common in acid rock drainage (ARD) systems. Voltammetric scans using a single gold microelectrode of water samples from geochemically distinct areas of the Río Tinto (RT) in southwestern Spain were clearly recognizable in the field and in samples stored at room temperature for over 6 months. Major voltammetric peaks of iron(III) and copper(II) were identified on a single constantly renewable gold microelectrode. Confirmation of these peaks was performed by spiking with standard metal solutions in the laboratory. This voltammetric technique is a rapid, direct and inexpensive in situ method for identification of water sources and their chemical characteristics, as well as an economical way to monitor environmental changes and remediation efforts.

  9. Electrochemical detection of uric acid using ruthenium-dioxide-coated carbon nanotube directly grown onto Si wafer

    Science.gov (United States)

    Shih, Yi-Ting; Lee, Kuei-Yi; Lin, Chung-Kuang

    2015-12-01

    Carbon nanotubes (CNTs) directly grown onto a Si substrate by thermal chemical vapor deposition were used in uric acid (UA) detection. The process is simple and formation is easy without the need for additional chemical treatments. However, CNTs lack selectivity and sensitivity to UA. To enhance the electrochemical analysis, ruthenium oxide was used as a catalytic mediator in the modification of electrodes. The electrochemical results show that RuO2 nanostructures coated onto CNTs can strengthen the UA signal. The peak currents of RuO2 nanostructures coated onto CNTs linearly increase with increasing UA concentration, meaning that they can work as electrodes for UA detection. The lowest detection limit and highest sensitivity were 55 nM and 4.36 µA/µM, respectively. Moreover, the characteristics of RuO2 nanostructures coated onto CNTs were examined by scanning electron microscopy, transmission electron microscopy, and Raman spectroscopy.

  10. Raldh expression in embryos of the direct developing frog Eleutherodactylus coqui and the conserved retinoic acid requirement for forelimb initiation.

    Science.gov (United States)

    Elinson, Richard P; Walton, Zachary; Nath, Kimberly

    2008-11-15

    Embryos of the direct developing frog, Eleutherodactylus coqui, provide opportunities to examine frog early limb development that are not available in species with tadpoles. We cloned two retinaldehyde dehydrogenase genes, EcRaldh1 and EcRaldh2, to see which enzyme likely supplies retinoic acid for limb development. EcRaldh1 is expressed in the dorsal retina, otic vesicle, pronephros, and pronephric duct, but not in the limb. EcRaldh2 is expressed early at the blastoporal lip and then in the mesoderm in the neurula, so this expression could function in forelimb initiation. Later EcRaldh2 is expressed in the mesoderm at the base of the limbs and in the ventral spinal cord where motor neurons innervating the limbs emerge. These observations on a frog support the functional conservation of EcRaldh2 in forelimb initiation in Osteichthyans and in limb patterning and motor neuron specification in tetrapods.

  11. Micro/nanofabrication of poly({sub L}-lactic acid) using focused ion beam direct etching

    Energy Technology Data Exchange (ETDEWEB)

    Oyama, Tomoko Gowa; Nagasawa, Naotsugu; Taguchi, Mitsumasa [Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki-machi, Takasaki, Gunma 370-1292 (Japan); Hinata, Toru; Washio, Masakazu [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); Oshima, Akihiro; Tagawa, Seiichi [Research Institute for Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555 (Japan); The Institute of Scientific and Industrial Research, Osaka University, 8-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2013-10-14

    Micro/nanofabrication of biocompatible and biodegradable poly({sub L}-lactic acid) (PLLA) using focused Ga ion beam direct etching was evaluated for future bio-device applications. The fabrication performance was determined with different ion fluences and fluxes (beam currents), and it was found that the etching speed and fabrication accuracy were affected by irradiation-induced heat. Focused ion beam (FIB)-irradiated surfaces were analyzed using micro-area X-ray photoelectron spectroscopy. Owing to reactions such as the physical sputtering of atoms and radiation-induced decomposition, PLLA was gradually carbonized with increasing C=C bonds. Controlled micro/nanostructures of PLLA were fabricated with C=C bond-rich surfaces expected to have good cell attachment properties.

  12. Comparison of Tungsten and Molybdenum Carbide Catalysts for the Hydrodeoxygenation of Oleic Acid

    NARCIS (Netherlands)

    Hollak, S.A.W.; Gosselink, R.J.A.; Es, van D.S.; Bitter, J.H.

    2013-01-01

    Group 6 (W, Mo) metal carbide catalysts are promising alternatives to hydrodesulfurization (NiMo, CoMo) catalysts and group 10 (Pd) type catalysts in the deoxygenation of vegetable fats/oils. Herein, we report a comparison of carbon nanofiber-supported W2C and Mo2C catalysts on activity, selectivity

  13. Direct Inhibition of Cellular Fatty Acid Synthase Impairs Replication of Respiratory Syncytial Virus and Other Respiratory Viruses.

    Directory of Open Access Journals (Sweden)

    Yamini M Ohol

    Full Text Available Fatty acid synthase (FASN catalyzes the de novo synthesis of palmitate, a fatty acid utilized for synthesis of more complex fatty acids, plasma membrane structure, and post-translational palmitoylation of host and viral proteins. We have developed a potent inhibitor of FASN (TVB-3166 that reduces the production of respiratory syncytial virus (RSV progeny in vitro from infected human lung epithelial cells (A549 and in vivo from mice challenged intranasally with RSV. Addition of TVB-3166 to the culture medium of RSV-infected A549 cells reduces viral spread without inducing cytopathic effects. The antiviral effect of the FASN inhibitor is a direct consequence of reducing de novo palmitate synthesis; similar doses are required for both antiviral activity and inhibition of palmitate production, and the addition of exogenous palmitate to TVB-3166-treated cells restores RSV production. TVB-3166 has minimal effect on RSV entry but significantly reduces viral RNA replication, protein levels, viral particle formation and infectivity of released viral particles. TVB-3166 substantially impacts viral replication, reducing production of infectious progeny 250-fold. In vivo, oral administration of TVB-3166 to RSV-A (Long-infected BALB/c mice on normal chow, starting either on the day of infection or one day post-infection, reduces RSV lung titers 21-fold and 9-fold respectively. Further, TVB-3166 also inhibits the production of RSV B, human parainfluenza 3 (PIV3, and human rhinovirus 16 (HRV16 progeny from A549, HEp2 and HeLa cells respectively. Thus, inhibition of FASN and palmitate synthesis by TVB-3166 significantly reduces RSV progeny both in vitro and in vivo and has broad-spectrum activity against other respiratory viruses. FASN inhibition may alter the composition of regions of the host cell membrane where RSV assembly or replication occurs, or change the membrane composition of RSV progeny particles, decreasing their infectivity.

  14. Comparison studies of propylene oxide addition to phenyloctadecanol and phenyloctadecanoic acid and the surface activity studies of their sulphated products

    Directory of Open Access Journals (Sweden)

    Ahmed, M. H.M.

    2001-10-01

    Full Text Available Phenyloctadecanol and phenyloctadecanoic acid were produced via Lewis acid catalyzed reaction of benzene and oleyl alcohol (60 ºC or oleic acid at (80 ºC respectively. A comparison study was achieved for the addition of propylene oxide to both substrates in the presence of base (KOH and Lewis acid (SbCl5 catalysts. It was found that, the hydroxypropylation of both substrates at low temperature via Lewis acid catalyst is more preferable than via the base catalyst. The surface activity of the sulphated products was determined. The results revealed that, the samples produced from alcohol (phenyloctadecanol show a better surface activity than that from acid (phenyloctadecanoic acid. On the other hand the samples produced from both substrates using Lewis acid catalyst have a better surface activity than that produced with the base catalyst.Se ha obtenido feniloctadecanol y ácido feniloctadecanoico vía reacción catalizada ácido de Lewis a partir de benceno y alcohol oleílico (60º C o ácido oleico (80º C respectivamente. Se ha llevado a cabo un estudio comparativo por adición de óxido de propileno a ambos sustratos en presencia de base (KOH y ácido de Lewis (SbCl5 como catalizadores. Se encontró que la hidroxipropilación de ambos sustratos a baja temperatura mediante catálisis ácido de Lewis es preferible a la catálisis básica. Se determinó la actividad superficial de los productos sulfatados. Los resultados mostraron que las muestras producidas a partir de alcohol (feniloctadecanol tenían una mejor actividad superficial que las producidas a partir de ácido (ácido feniloctadecanoico. Por otro lado, las muestras producidas a partir de ambos sustratos utilizando catalizador ácido de Lewis tuvieron una actividad superficial mejor que las producidas con catálisis básica.

  15. Site directed mutagenesis of amino acid residues at the active site of mouse aldehyde oxidase AOX1.

    Directory of Open Access Journals (Sweden)

    Silvia Schumann

    Full Text Available Mouse aldehyde oxidase (mAOX1 forms a homodimer and belongs to the xanthine oxidase family of molybdoenzymes which are characterized by an essential equatorial sulfur ligand coordinated to the molybdenum atom. In general, mammalian AOs are characterized by broad substrate specificity and an yet obscure physiological function. To define the physiological substrates and the enzymatic characteristics of mAOX1, we established a system for the heterologous expression of the enzyme in Escherichia coli. The recombinant protein showed spectral features and a range of substrate specificity similar to the native protein purified from mouse liver. The EPR data of recombinant mAOX1 were similar to those of AO from rabbit liver, but differed from the homologous xanthine oxidoreductase enzymes. Site-directed mutagenesis of amino acids Val806, Met884 and Glu1265 at the active site resulted in a drastic decrease in the oxidation of aldehydes with no increase in the oxidation of purine substrates. The double mutant V806E/M884R and the single mutant E1265Q were catalytically inactive enzymes regardless of the aldehyde or purine substrates tested. Our results show that only Glu1265 is essential for the catalytic activity by initiating the base-catalyzed mechanism of substrate oxidation. In addition, it is concluded that the substrate specificity of molybdo-flavoenzymes is more complex and not only defined by the three characterized amino acids in the active site.

  16. Phospholipase D2 specifically regulates TREK potassium channels via direct interaction and local production of phosphatidic acid.

    Science.gov (United States)

    Comoglio, Yannick; Levitz, Joshua; Kienzler, Michael A; Lesage, Florian; Isacoff, Ehud Y; Sandoz, Guillaume

    2014-09-16

    Membrane lipids serve as second messengers and docking sites for proteins and play central roles in cell signaling. A major question about lipid signaling is whether diffusible lipids can selectively target specific proteins. One family of lipid-regulated membrane proteins is the TWIK-related K channel (TREK) subfamily of K2P channels: TREK1, TREK2, and TWIK-related arachdonic acid stimulated K(+) channel (TRAAK). We investigated the regulation of TREK channels by phosphatidic acid (PA), which is generated by phospholipase D (PLD) via hydrolysis of phosphatidylcholine. Even though all three of the channels are sensitive to PA, we found that only TREK1 and TREK2 are potentiated by PLD2 and that none of these channels is modulated by PLD1, indicating surprising selectivity. We found that PLD2, but not PLD1, directly binds to the C terminus of TREK1 and TREK2, but not to TRAAK. The results have led to a model for selective lipid regulation by localization of phospholipid enzymes to specific effector proteins. Finally, we show that regulation of TREK channels by PLD2 occurs natively in hippocampal neurons.

  17. Comparison of tranexamic acid (Transamin and traditional therapy for sudden deafness.

    Directory of Open Access Journals (Sweden)

    Ohsaki,Katsuichiro

    1980-11-01

    Full Text Available The effectiveness of tranexamic acid treatment for sudden deafness was studied in detail. The results of treatment with tranexamic acid administration in 19 cases (25 ears of sudden deafness and two historical control groups using various treatments were compared by the chi square contingency test. The data suggested that tranexamic acid treatment may be superior to traditional treatments especially if treatment is begun early. Among ears treated with tranexamic acid, 11 ears (44% were healed or recovered remarkably, 8 ears (32% recovered slightly and 6 ears (24% were unchanged or worsened. Fibrinolysis in the inner ear may be the pathophysiology of sudden deafness. Treatment with tranexamic acid starting within 4 days after onset of symptoms was most effective in patients whose initial audiogram was flat or concave, initial average hearing loss at 5 frequencies (250 Hz, 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz was between 23 dB and 76 dB (mean; 45.1 dB and was not accompanied by dizziness.

  18. Comparison of apparent ileal amino acid digestibility of feed ingredients measured with broilers, layers, and roosters.

    Science.gov (United States)

    Huang, K H; Li, X; Ravindran, V; Bryden, W L

    2006-04-01

    The apparent ileal digestibility of amino acids in 7 feed ingredients was determined using broilers, layers, and roosters. The ingredients included 3 cereals (wheat, sorghum, and corn), 3 oilseed meals (canola, cottonseed, and soybean meals), and 1 animal protein meal (meat and bone meal). Dietary protein in the assay diets was supplied solely by the test ingredient. All diets contained 20 g/kg of acid-insoluble ash as an indigestible marker, and each diet was offered ad libitum in mash form to 5 replicate pens of broilers and layers, and 4 replicate pens of roosters. The digestibility coefficients of individual amino acids for wheat, corn, and sorghum were higher (P meal, cottonseed meal, and meat and bone meal was similar among the 3 classes of chickens. The digestibility of amino acids in soybean meal was higher (P < 0.05) for layers compared with those for broilers and roosters but similar between broilers and roosters. These results suggest that the class of chickens significantly influenced the apparent ileal digestibility of amino acids in some feed ingredients.

  19. Combined prenatal and postnatal butyl paraben exposure produces autism-like symptoms in offspring: comparison with valproic acid autistic model.

    Science.gov (United States)

    Ali, Elham H A; Elgoly, Amany H Mahmoud

    2013-10-01

    The aim of this work is to evaluate the impact of butyl paraben (BP) in brain of the pups developed for mothers administered BP from early pregnancy till weaning and its effect on studying the behavior, brain neurotransmitters and brain derived neurotrophic factor BDNF via comparing the results with valproic acid (VA) autistic-rat model preparing by a single oral injection dose of VA (800 mg/kg b.wt) at the 12.5 days of gestation. Butyl paraben was orally and subcutaneously administered (200 mg/kg b.wt) to pregnant rats from gestation day 1 to lactation day 21. The offspring male rats were subjected at the last 3 days of lactation to Morris water maze and three chamber sociability test then decapitated and the brain was excised and dissected to the cortex, hippocampus, cerebellum, midbrain and pons for the determination of norepinephrine, dopamine and serotonin (NE, DA and 5-HT) and cortex amino acids and whole brain BDNF. The results showed similar social and learning and memory behavioral deficits in VA rat model and the butyl paraben offspring in comparison with the controls. Also, some similar alterations were observed in monoamine content, amino acids and BDNF factor in the autistic-like model and butyl paraben offspring in comparison with the controls. The alterations were recorded notably in hippocampus and pons NE, midbrain DA, hippocampus and midbrain 5-HT, and frontal cortex GABA and asparagine. These data suggest that prenatal exposure to butyl paraben induced neuro-developmental disorders similar to some of the neurodevelopmental disorders observed in the VA model of autism.

  20. Effects of celecoxib on acid-challenged gastric mucosa of rats: comparison with metamizol and piroxicam.

    Science.gov (United States)

    Berenguer, Bettina; Alarcón De La Lastra, Catalina; Motilva, Virginia; La Casa, Carmen; Herrerias, Juan Manuel; Pozo, David; Calero, María José Martin

    2004-06-01

    Selective COX-2 inhibitors have been shown to produce fewer gastrointestinal adverse reactions than classical NSAIDs. Nevertheless, these new agents may worsen and delay the healing of experimentally induced gastric ulcers in animals. In this study, we compared the effects of a selective COX-2 inhibitor (celecoxib), a preferential COX-1 inhibitor (piroxicam), and a nonnarcotic analgesic (metamizol) on normal gastric mucosa of rats and, on the other hand, in a setting of preexisting acute gastric lesions induced by 0.6 N hydrochloric acid. Under normal conditions, only piroxicam produced appreciable gastric lesions. However, after acid challenge the three assayed drugs induced significant macroscopic and microscopic damage. Myeloperoxidase activity as an index of neutrophil infiltration was elevated with celecoxib and piroxicam on normal gastric mucosa. On inflamed mucosa, celecoxib augmented enzymatic activity at the lower dose, which was parallelled by an increase in the interleukin 1beta level. Acid instillaton produced a significant rise in PGE2 content at 7 hr. Drug treatment after acid challenge decreased prostaglandin values in all cases, although to a lesser extent than after single drug dose administration. COX-2 mRNA expression was visible 1 hr after acid application, whereas COX-2 protein could only be detected at 7 hr. Piroxicam increased both expression levels. All NSAIDs enhanced transforming growth factor alpha and epidermal growth factor receptor immunoreactivity around the acid-induced lesions. It is concluded that selective COX-2 inhibitors, like conventional NSAIDs, impair the healing of gastric damage, and therefore special attention should be paid in patients with gastric pathologies.

  1. Preparation of La-Mo-V mixed-oxide systems and their application in the direct synthesis of acetic acid

    Institute of Scientific and Technical Information of China (English)

    Hamid Reza Arandiyan; Matin Parvari

    2008-01-01

    In this study,mixed metal oxides developed with a perovskite-type structure that show great potential for use in catalysis.Perovskite oxide catalysts with the composition LaMoxV1-xOn(z=0.1,0.3,0.5,0.7,and 0.9)have been synthe sized by the sol-gel method and then used in the ethane dry reforming reaction for the direct synthesis of acetic acid.The influence of the nature of the metallic source(metal,nitrate,acetylacetonate,and ammonium)on gel formation has been stud ied by Fourier-transfornl infrared spectroscopy(FT-IR)and thermogravimetric analysis(TGA-DTA).After calcination,the obtained perovskites were characterized bv X-ray diffraction(XRD)and energy-dispersive X-ray spectrometry(EDS)coupled with scanning electron microscopy(SEM).The catalysts were then subjected tO thermo-programmed reduction(TPR).The surface area(BET)was found to increase from 2.6 m2/g(x=0.1)to 5.1 m1/g(x=1.0)with increasing molybdenum content following calcinations at 750℃,and pure LaMoxV1-xOn perovskite was obtained with good homogeneity.The catalysts have been characterized by XRD,SEM,EDS,and carbon analysis(CA).The results indicate that through this synthesis it iS possible to obtain highly crystalline.homogeneous and pure solids,with well-defined structures.The direct synthesis of acetic acid from ethane over the perovskite catalysts was studied at temperatures between 450 and 850℃ and elevated pressures between 1 and 8 bar.It was foand that the yield of acetic acid and the selectivity of its formation could be increased by incorporating more molybdenum into the perovskite structure.The experimental studies have shown that the calcination temperature and the molybdenum content have a significant influence on the catalytic activity.Amongst the catalysts tested,LaMo0.7 V0.3O4.2exhibited the best activity and stability.

  2. Determining Sound Source Orientation from Source Directivity and Real Multi-Microphone Recordings: Experimental Comparisons using both Analytical and Measured Directivity Models

    DEFF Research Database (Denmark)

    Guarato, Francesco; Hallam, John; Vanderelst, Dieter

    2009-01-01

    This paper presents a method for estimating the orientation of a directional sound source emitting a broadband acoustic signal being recorded by a microphone array, given source directivity, microphone positions with respect to the source and recordings of the call. Such a method has been tested...... an analytical directivity model and when directivity is provided by measurements. Results show that method estimates orientations very close to the true ones, and that analytical directivity is a good approximation of the measured one. We also point out the limits we must respect to make the method precise....... The signal emitted by the source is broadband, like the signals many bats use while echolocating. Indeed, our intended final application of the method is to estimate the orientations a bat assumes while hunting over water....

  3. Reduction of Cysteine Sulfinic Acid in Peroxiredoxin by Sulfiredoxin Proceeds Directly Through a Sulfinic Phosphoryl Ester Intermediate

    Energy Technology Data Exchange (ETDEWEB)

    Jonsson,T.; Murray, M.; Johnson, L.; Lowther, W.

    2008-01-01

    Sulfiredoxin (Srx) catalyzes a novel enzymatic reaction, the reduction of protein cysteine sulfinic acid, Prx-SO{sub 2}{sup -}. This reaction is unique to the typical 2-Cys peroxiredoxins (Prx) and plays a role in peroxide-mediated signaling by regulating the activity of Prxs. Two mechanistic schemes have been proposed that differ regarding the first step of the reaction. This step involves either the direct transfer of the {gamma}-phosphate of ATP to the Prx molecule or through Srx acting as a phosphorylated intermediary. In an effort to clarify this step of the Srx reaction, we have determined the 1.8 Angstroms resolution crystal structure of Srx in complex with ATP and Mg2+. This structure reveals the role of the Mg2+ ion to position the {gamma}-phosphate toward solvent, thus preventing an in-line attack by the catalytic residue Cys-99 of Srx. A model of the quaternary complex is consistent with this proposal. Furthermore, phosphorylation studies on several site-directed mutants of Srx and Prx, including the Prx-Asp mimic of the Prx-SO{sub 2}{sup -} species, support a mechanism where phosphorylation of Prx-SO{sub 2}{sup -} is the first chemical step.

  4. Modelling fragmentations of amino-acids after resonant electron attachment: quantum evidence of possible direct -OH detachment

    Energy Technology Data Exchange (ETDEWEB)

    Panosetti, C.; Sebastianelli, F.; Gianturco, F.A. [Department of Chemistry and CNISM, University of Rome -La Sapienza-, Roma (Italy); Baccarelli, I. [CASPUR, Supercomputing Consortium for University and Research, Roma (Italy)

    2010-10-15

    We investigate some aspects of the radiation damage mechanisms in biomolecules, focusing on the modelling of resonant fragmentation caused by the attachment of low-energy electrons (LEEs) initially ejected by biological tissues when exposed to ionizing radiation. Scattering equations are formulated within a symmetry-adapted, single-center expansion of both continuum and bound electrons, and the interaction forces are obtained from a combination of ab initio calculations and a nonempirical model of exchange and correlation effects developed in our group. We present total elastic scattering cross-sections and resonance features obtained for the equilibrium geometries of glycine, alanine, proline and valine. Our results at those geometries of the target molecules are briefly shown to qualitatively explain some of the fragmentation patterns obtained in experiments. We further carry out a one-dimensional (1D) modeling for the dynamics of intramolecular energy transfers mediated by the vibrational activation of selected bonds: our calculations indicate that resonant electron attachment to glycine can trigger direct, dissociative evolution of the complex into (Gly-OH)- and -OH losses, while they also find that the same process does not occur via a direct, 1D dissociative path in the larger amino acids of the present study. (authors)

  5. Direct determination of flavor relevant and further branched-chain fatty acids from sheep subcutaneous adipose tissue by gas chromatography with mass spectrometry.

    Science.gov (United States)

    Kaffarnik, Stefanie; Preuß, Siegfried; Vetter, Walter

    2014-07-11

    4-Methyloctanoic acid, 4-ethyloctanoic acid and 4-methylnonanoic acid are key-flavor compounds of sheep and goat. Yet, the low amounts of these volatile branched-chain fatty acids (vBCFAs) in the fat of the ruminants hampered their determination on a routine basis. In this work we developed a gas chromatography/mass spectrometry selected ion monitoring (GC/MS-SIM) method for the direct determination of the vBCFAs as methyl esters, which were obtained after transesterification of subcutaneous adipose tissue of sheep. The excellent sensitivity of the GC/MS-SIM method (limit of quantification, LOQ, 3.6-4.8μg/g; limit of detection, LOD, 1.1-1.4μg/g for 4-Me-8:0, 4-Et-8:0 and 4-Me-9:0) enabled us to determine the three vBCFAs without an enrichment step. Subcutaneous adipose sheep tissue of three different breeds contained 23-88μg/g 4-methyloctanoic acid, 13-26μg/g 4-ethyloctanoic acid and ∼2.9-18μg/g 4-methylnonanoic acid. Since all fatty acids were present in the FAME fraction, the samples could be screened for further branched-chain FAMEs. After elimination of unsaturated fatty acids by hydrogenation (the presence of some unsaturated fatty acids could be verified by this measure), additional measurements in SIM and full scan modes of methyl esters and picolinyl esters enabled the determination of further 97 saturated fatty acids in the samples with eight to 20 carbons. The method is suited for routine analysis and may be useful to investigate the reasons for the abundance/absence of 4-methyloctanoic acid, 4-ethyloctanoic acid and 4-methylnonanoic acid and further branched-chain fatty acids in sheep and goat.

  6. Comparison of values derived from selected flours by fat acidity methods of the American Association of Cereal Chemists and the International Organization for Standardization.

    Science.gov (United States)

    Lane, R H; Erickson, R L

    1988-01-01

    Fat acidity values were determined on 8 commercially available flours by the American Association of Cereal Chemists method (AACC-02-01A) and by the International Organization for Standardization method (ISO-7305). Comparisons of means obtained by these 2 methods indicated that the ISO method produced results that were 1.4-2.5 times greater (P less than 0.001) than those for the AACC method. These data are consistent with a previous report which indicated that acidic materials (phosphates and amino acids) other than fatty acids are extracted by 95% alcohol (ISO method), whereas fatty acids alone are extracted by petroleum ether (AACC method). Fat acidity values obtained by AACC methodology employing Soxhlet and continuous extraction were also compared. No difference in fat acidity means existed with respect to extraction technique except for an aged whole wheat flour sample which produced a higher value (P = 0.05) by continuous extraction.

  7. [Sweat chloride measurement using direct potentiometry: Spotchem(®) (Elitech-Arkray) evaluation and comparison with coulometry and conductivity].

    Science.gov (United States)

    Nguyen-Khoa, Thao; Borgard, Jean-Pierre; Miled, Ryad; Rota, Michèle

    2013-01-01

    Sweat chloride (Cl(-)) measurement is a key step for the diagnosis of cystic fibrosis. The coulometric technique is validated in this context by international guidelines. The aim of our study was to evaluate the assay for sweat Cl(-) ions using direct potentiometry on disposable cassette (Spotchem™ SE EL-1520, Elitech-Arkray) by comparing results to those obtained on the same sample, by coulometry (Chloride analyser Sherwood 926S, Dutscher). To complete our table of correspondence between the results of Cl(-) ions and sweat conductivity (Sweat Check™ 3100), conductivity has been also achieved for 99 of the 139 sweat samples studied. Linearity of each technique performed extends from 10 to 120 mmol/L. The coefficients of variation within and between runs are < 5%. Comparison of 139 results (Passing - Bablock regression) shows a significant difference (p < 0.001): [Spotchem] = 1.026 [Chloride analyser] + 1.8, r = 0.996. After correction with regression factors, only 6 pairs of values (4.6%) had a difference greater than ± 5 mmol/L). The results of conductivity measurement is strongly correlated with those of Cl(-) ions (r = 0.959 for Chloride analyser and 0.965 for Spotchem; p = 0.576) with a linear relationship between the decision thresholds from 30 to 60 mmol/L Cl(-). Sweat Cl(-) determinations using Spotchem™ analyser meet the criteria required by analytical recommendations. The technique is standardized, easy to perform and fast. Its good practicability makes the sweat test independent to operator and allows point-of care use.

  8. Endothelial dysfunction of bypass graft: direct comparison of in vitro and in vivo models of ischemia-reperfusion injury.

    Directory of Open Access Journals (Sweden)

    Gábor Veres

    Full Text Available Although, ischemia/reperfusion induced vascular dysfunction has been widely described, no comparative study of in vivo- and in vitro-models exist. In this study, we provide a direct comparison between models (A ischemic storage and in-vitro reoxygenation (B ischemic storage and in vitro reperfusion (C ischemic storage and in-vivo reperfusion.Aortic arches from rats were stored for 2 hours in saline. Arches were then (A in vitro reoxygenated (B in vitro incubated in hypochlorite for 30 minutes (C in vivo reperfused after heterotransplantation (2, 24 hours and 7 days reperfusion. Endothelium-dependent and independent vasorelaxations were assessed in organ bath. DNA strand breaks were assessed by TUNEL-method, mRNA expressions (caspase-3, bax, bcl-2, eNOS by quantitative real-time PCR, proteins by Western blot analysis and the expression of CD-31 by immunochemistry. Endothelium-dependent maximal relaxation was drastically reduced in the in-vivo models compared to ischemic storage and in-vitro reperfusion group, and no difference showed between ischemic storage and control group. CD31-staining showed significantly lower endothelium surface ratio in-vivo, which correlated with TUNEL-positive ratio. Increased mRNA and protein levels of pro- and anti-apoptotic gens indicated a significantly higher damage in the in-vivo models.Even short-period of ischemia induces severe endothelial damage (in-vivo reperfusion model. In-vitro models of ischemia-reperfusion injury can be limitedly suited for reliable investigations. Time course of endothelial stunning is also described.

  9. Comparison of geometrical isomerization of unsaturated fatty acids in selected commercially refined oils

    Energy Technology Data Exchange (ETDEWEB)

    Tasan, M.; Gecgel, U.; Demirci, M.

    2011-07-01

    Four different commercially refined vegetable oils were analyzed by capillary gas-liquid chromatography for their trans fatty acid contents. The results obtained showed that the total trans FA contents in refined sunflower, corn, soybean, and hazelnut oils were 0.68 {+-} 0.41, 0.51 {+-} 0.24, 1.27 {+-} 0.57, and 0.26 {+-} 0.07% of total FA, respectively. The total trans FA comprised isomers of the C18:1, C18:2 and C18:3 FA. Meanwhile, five brands of the refined sunflower oil and two brands of hazelnut oil contained no measurable amounts of total trans C18:3 acids. The total trans C18:2 acid was the predominant trans FA found in the refined sunflower and corn oils, while trans polyunsaturated FAs for the refined soybean oils were found at high levels. However, total trans C18:1 acid was the major trans FA for refined hazelnut oils. The commercially refined vegetable oils with a relatively high total polyunsaturated FA contained considerable amounts of trans polyunsaturated isomers. This study indicates that it is necessary to optimize industrial deodorization, especially the time and temperature, for each different FA composition of oil used. (Author) 28 refs.

  10. Comparison and chemometric analysis of the phenolic compounds and organic acids composition of chinese wines.

    Science.gov (United States)

    Tang, Ke; Ma, Lei; Han, Ye-Hui; Nie, Yao; Li, Ji-Ming; Xu, Yan

    2015-01-01

    Characteristics of 106 wines from 5 major grape varieties and 3 typical geographic regions in China were investigated by means of profiling of organic acids and phenolic compounds analysis. An ultra-performance liquid chromatography method was developed and thus, large number of samples could be determined in a quick and reliable way. The results showed that different origins and varieties were characteristic of various profiles of organic acid and phenolic compounds. In order to investigate possible correlation between organic acids and phenolic compounds content and grape variety and/or geographical origin, analysis of variance and linear discriminant analysis (LDA) were conducted. A satisfactory LDA result for red wines according to geographic origin was obtained, in which the correct classification was 100% and the leave-one-out validation accuracy was 90%. The corresponding results of white wines were 91% and 86%, respectively. When LDA was processed, according to grape varieties, the proportionality of successfully classified wines was 96%, while the leave-one-out validation accuracy was 94%. The organic acids and phenolic compounds profiles were useful in the classification of Chinese wines according to grape variety and geographic origin.

  11. Environmental comparison of biobased chemicals from glutamic acid with their petrochemical equivalents

    NARCIS (Netherlands)

    Lammens, T.M.; Potting, J.; Sanders, J.P.M.; Boer, de I.J.M.

    2012-01-01

    Glutamic acid is an important constituent of waste streams from biofuels production. It is an interesting starting material for the synthesis of biobased chemicals, thereby decreasing the dependency on fossil fuels. The objective of this paper was to compare the environmental impact of four biobased

  12. Comparison of amino acid oxidation and urea metabolism in haemodialysis patients during fasting and meal intake

    NARCIS (Netherlands)

    Veeneman, JM; Kingma, HA; Stellaard, F; de Jong, PE; Reijngoud, DJ; Huisman, RM

    2004-01-01

    Background. The PNA (protein equivalent of nitrogen appearance) is used to calculate protein intake from urea kinetics. One of the essential assumptions in the calculation of PNA is that urea accumulation in haemodialysis (HD) patients is equivalent to amino acid oxidation. However, urea is hydrolys

  13. Durability to Chemical Attack by Acids of Epoxy Microconcretes by Comparison to Cementitious Ones

    Directory of Open Access Journals (Sweden)

    Elhem Ghorbel

    2016-01-01

    Full Text Available This research deals with the durability of micropolymer concrete (MPC obtained by mixing an epoxy resin with fine and coarse sand particles. In particular the resistance of the micropolymer concrete to chemical solutions (citric acid C6H8O7, sulfuric acid H2SO4, and hydrochloric acid HCl is investigated and compared to this of Portland cement microconcrete. Two MPC are tested. The first is formulated with 9% mass fraction of epoxy polymer whereas calcareous fillers have been incorporated in the second formulation in order to reduce the percentage of the epoxy binder. It is shown that a microconcrete designed with 7% of epoxy, 10% of fillers, and 83% of aggregates is characterized by higher physical and mechanical properties than those of the MPC formulated with 9% of epoxy binder. The mechanical properties of the resulting materials after their exposure to the three selected acid solutions at different durations were studied through compressive, three points bending and ultrasonic wave propagation tests. The obtained results are compared to those of microcement concretes (MCC tested under the same conditions as MPC. The results show that both microepoxy polymer concretes exhibit better mechanical properties and highest resistance to chemical attack than the microcement concrete.

  14. Comparison and analysis of fatty acids, sterols, and tocopherols in eight vegetable oils.

    Science.gov (United States)

    Li, Changmo; Yao, Yunping; Zhao, Guozhong; Cheng, Wen; Liu, Huilin; Liu, Chunyang; Shi, Zhen; Chen, Yao; Wang, Shuo

    2011-12-14

    The similarities and differences of eight vegetable oils produced in China were investigated in terms of their fatty acid, sterol, and tocopherol compositions and subsequent data processing by hierarchical clustering analysis and principal component analysis. The lipid profiles, acquired by analytical techniques tailored to each lipid class, revealed great similarities among the fatty acid profiles of corn and sesame oil as well as few differences in their sterol profiles. It turns out that not only was there great similarity between the fatty acid profiles of corn oil and sesame oil but also there were not too many differences for the sterol profiles. Sunflower and tea-seed oil showed similar sterol compositions, while the tea-seed oil tocopherol was very similar to palm oil. The results demonstrated that the use of only one of these profiles was unreliable for indentifying oil origin and authenticity. In contrast, the use of the sterol or tocopherol profile together with the fatty acid profile more accurately discriminates these oils.

  15. Comparison of the effects of topical fusidic acid and rifamycin on wound healing in rats.

    Science.gov (United States)

    Gurel, Mehmet S; Naycı, Sillan; Turgut, Aslı V; Bozkurt, Erol R

    2015-02-01

    Wound healing is an active and dynamic process that begins from the moment of injury. Any delay in the initiation of the response to injury can prolong the healing process. The aim of this study was to investigate the effects of topically applied fusidic acid and rifamycin on wound healing in a full-thickness wound model. Ten female Sprague-Dawley rats, aged 4 months and weighing 200-250 g, were used. Four rifamycin (R), four fusidic acid (F) and four control (K) areas were generated on their backs by using a 5-mm punch biopsy pen. On the 4th, 7th, 14th and 21st days, biopsies were taken from each wound area of all the rats. Fusidic acid group demonstrated a statistically significant increase of collagen and intensity of fibroblast proliferation on the 21st day of wound healing, whereas in the rifamycin group, healing time was, as expected, similar to physiological wound-healing phases. Despite the limited number of subjects, topical fusidic acid was found to delay wound healing by prolonging fibroblast proliferation.

  16. Comparison of three methods for isolation of nucleic acids from membranate inner ear tissue of rats

    Institute of Scientific and Technical Information of China (English)

    KONG Wei-jia; WANG Ying; WANG Qiong; HAN Yue-chen; HU Yu-juan

    2006-01-01

    Background Mitochondrial DNA mutations have been found in sensorineural deafness. The aim of this study was to compare three methods for extraction of nucleic acid from membranate inner ear tissue of rats.Methods Alkaline denaturation, a conventional phenol-chloroform method and Trizol reagent were respectively used to extract the slight nucleic acid from membranate inner ear tissue of rats. We assessed the amount and quality of nucleic acid using a UV-spectrometer and polymerase chain reaction (PCR).Results The yield and purity (OD260/OD280) of DNA from inner ear tissue using the phenol-chloroform method was the highest of the three methods. Mitochondrial DNA (mtDNA) fragment can be amplified by PCR from nucleic acid prepared by all methods, while no nuclear DNA (nDNA) fragment can be amplified by method of alkaline denaturation. Both nuclear and mitochondrial genescould be amplified by reverse transcriptional PCR from the RNA prepared by Trizol reagent.Conclusion Adequate amount and high-quality of mtDNA, nDNA and RNA were obtained from unilateral membranate inner ear tissue of rats. Method of alkaline denaturation could be chosen when mtDNA without nDNA was needed, while phenol-chloroform method was suitable for extracting total DNA (including nDNA and mtDNA); method with Trizol reagent was suitable for extracting total RNA and total DNA.

  17. Environmental Comparison of Biobased Chemicals from Glutamic Acid with Their Petrochemical Equivalents

    NARCIS (Netherlands)

    Lammens, T.M.; Potting, J.; Sanders, J.P.M.; Boer, de I.J.M.

    2011-01-01

    Glutamic acid is an important constituent of waste streams from biofuels production. It is an interesting starting material for the synthesis of biobased chemicals, thereby decreasing the dependency on fossil fuels. The objective of this paper was to compare the environmental impact of four biobased

  18. Amino Acids Generated from Hydrated Titan Tholins: Comparison with Miller-Urey Electric Discharge Products

    Science.gov (United States)

    Cleaves, H. James, II; Neish, Catherine; Callahan, Michael P.; Parker, Eric; Fernandez, Facundo M.; Dworkin, Jason P.

    2014-01-01

    Various analogues of Titan haze particles (termed tholins) have been made in the laboratory. In certain geologic environments on Titan, these haze particles may come into contact with aqueous ammonia (NH3) solutions, hydrolyzing them into molecules of astrobiological interest. A Titan tholin analogue hydrolyzed in aqueous NH3 at room temperature for 2.5 years was analyzed for amino acids using highly sensitive ultra-high performance liquid chromatography coupled with fluorescence detection and time-of-flight mass spectrometry (UHPLC-FDToF-MS) analysis after derivatization with a fluorescent tag. We compare here the amino acids produced from this reaction sequence with those generated from room temperature Miller-Urey (MU) type electric discharge reactions. We find that most of the amino acids detected in low temperature MU CH4N2H2O electric discharge reactions are generated in Titan simulation reactions, as well as in previous simulations of Triton chemistry. This argues that many processes provide very similar mixtures of amino acids, and possibly other types of organic compounds, in disparate environments, regardless of the order of hydration. Although it is unknown how life began, it is likely that given reducing conditions, similar materials were available throughout the early Solar System and throughout the universe to facilitate chemical evolution.

  19. Comparison of unimolecular decomposition pathways for carboxylic acids of relevance to biofuels.

    Science.gov (United States)

    Clark, Jared M; Nimlos, Mark R; Robichaud, David J

    2014-01-09

    Quantum mechanical molecular modeling is used [M06-2X/6-311++G(2df,p)] to compare activation energies and rate constants for unimolecular decomposition pathways of saturated and unsaturated carboxylic acids that are important in the production of biofuels and that are models for plant and algae-derived intermediates. Dehydration and decarboxylation reactions are considered. The barrier heights to decarboxylation and dehydration are similar in magnitude for saturated acids (∼71 kcal mol(-1)), with an approximate 1:1 [H2O]/[CO2] branching ratio over the temperature range studied (500-2000 K). α,β-Unsaturation lowers the barrier to decarboxylation between 2.2 and 12.2 kcal mol(-1) while increasing the barriers to dehydration by ∼3 kcal mol(-1). The branching ratio, as a result, is an order of magnitude smaller, [H2O]/[CO2] = 0.07. For some α,β-unsaturated acids, six-center transition states are available for dehydration, with barrier heights of ∼35.0 kcal mol(-1). The branching ratio for these acids can be as high as 370:1. β,γ-Unsaturation results in a small lowering in the barrier height to decarboxylation (∼70.0 kcal mol(-1)). β,γ-Unsaturation also leads to a lowering in the dehydration pathway from 1.7 to 5.1 kcal mol(-1). These results are discussed with respect to predicted kinetic values for acids of importance in biofuels production.

  20. Fatty acid composition and biogenic amines in acidified and fermented fish silage: a comparison study.

    Science.gov (United States)

    Özyurt, Gülsün; Gökdoğan, Saadet; Şimşek, Ayşe; Yuvka, Ilknur; Ergüven, Merve; Kuley Boga, Esmeray

    2016-01-01

    In the presented study, ensiling of discard fish by acidification or fermentation was evaluated. Klunzinger's ponyfish which is a discard fish was used for the production of fish silage by acidification (3% formic acid for Method FA; 1.5% formic and 1.5% sulphuric acid for Method FASA) and fermentation (Lactobacillus plantarum for Method LP and Streptococcus thermophilus for Method ST). The chemical, microbiological and nutritional properties of the differently preserved fish silages were estimated during a storage period of 60 d at ambient temperature. Compared to the raw material, a slight increase in saturated fatty acids and a slight decrease in polyunsaturated fatty acids were observed in all silages. At the end of the storage period, the aerobic bacteria counts after applying Methods FA, FASA, LP and ST amounted to 2.35, 2.39, 5.77 and 5.43 log cfu/g, respectively. The analysis of thiobarbituric acid revealed that acidification of silages accelerated the lipid oxidation. Nine biogenic amines were found in raw fish and different silages. The initial histamine concentration in raw fish was 0.17 mg/100 g and in all silages it remained at low levels during the storage period. The initial tyramine content was found to be 1.56 mg/100 g in raw fish and increased significantly in all silages. The increase of the tyramine content in fermented silages was considerably higher than in acidified silages (23-48 mg/100 g and 5-10 mg/100 g, respectively). It can be concluded that acidified or fermented fish silage should be considered as potential feed component for animals because of its high nutritional value and appropriate microbiological and chemical quality.

  1. Modeling DNA hydration: comparison of calculated and experimental hydration properties of nuclic acid bases.

    Science.gov (United States)

    Poltev, V I; Malenkov, G G; Gonzalez, E J; Teplukhin, A V; Rein, R; Shibata, M; Miller, J H

    1996-02-01

    Hydration properties of individual nucleic acid bases were calculated and compared with the available experimental data. Three sets of classical potential functions (PF) used in simulations of nucleic acid hydration were juxtaposed: (i) the PF developed by Poltev and Malenkov (PM), (ii) the PF of Weiner and Kollman (WK), which together with Jorgensen's TIP3P water model are widely used in the AMBER program, and (iii) OPLS (optimized potentials for liquid simulations) developed by Jorgensen (J). The global minima of interaction energy of single water molecules with all the natural nucleic acid bases correspond to the formation of two water-base hydrogen bonds (water bridging of two hydrophilic atoms of the base). The energy values of these minima calculated via PM potentials are in somewhat better conformity with mass-spectrometric data than the values calculated via WK PF. OPLS gave much weaker water-base interactions for all compounds considered, thus these PF were not used in further computations. Monte Carlo simulations of the hydration of 9-methyladenine, 1-methyluracil and 1-methylthymine were performed in systems with 400 water molecules and periodic boundary conditions. Results of simulations with PM potentials give better agreement with experimental data on hydration energies than WK PF. Computations with PM PF of the hydration energy of keto and enol tautomers of 9-methylguanine can account for the shift in the tautomeric equilibrium of guanine in aqueous media to a dominance of the keto form in spite of nearly equal intrinsic stability of keto and enol tautomers. The results of guanine hydration computations are discussed in relation to mechanisms of base mispairing errors in nucleic acid biosynthesis. The data presented in this paper along with previous results on simulation of hydration shell structures in DNA duplex grooves provide ample evidence for the advantages of PM PF in studies of nucleic-acid hydration.

  2. Hydroxycinnamic acids are ester-linked directly to glucosyl moieties within the lignan macromolecule from flaxseed hulls

    NARCIS (Netherlands)

    Struijs, K.; Vincken, J.P.; Verhoef, R.P.; Voragen, A.G.J.; Gruppen, H.

    2008-01-01

    In flaxseed hulls, lignans are present in an oligomeric structure. Secoisolariciresinol diglucoside (SDG), ester-linked to hydroxy-methyl-glutaric acid (HMGA), forms the backbone of this lignan macromolecule. The hydroxycinnamic acids p-coumaric acid glucoside (CouAG) and ferulic acid glucoside (FeA

  3. A comparison of the Maillard reactivity of proline to other amino acids using pyrolysis-molecular beam mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Luc Moens; Robert J. Evans; Michael J. Looker; Mark R. Nimlos [National Bioenergy Center, Golden, CO (United States). National Renewable Energy Laboratory

    2004-08-01

    Maillard chemistry, or the low temperature condensation of amino acids and carbohydrates, is shown to be relevant to the practical regime of biomass pyrolysis and leads to dramatic changes in low-temperature volatile products and residual solid structure. Mixtures of amino acids and glucose were subjected to a two-temperature heating sequence (5 min each at 170 and 325{sup o}C) and the volatile products analyzed by molecular beam mass spectrometry. Significant volatile yield was observed from the mixtures at 170{sup o}C where neither amino acids nor glucose generated volatile material in the time frame studied. Proline was the most active of the amino acids studied. Volatile products at low temperature included the diketopiperazine, which were generated in higher yields than from proline alone. Also generated were Maillard condensation such as 1-(1{prime}-pyrrolidinyl)-2-propanone. These products were also generated at 325{sup o}C, but in addition, the mass spectra included evidence for the direct formation of nitrogen-containing aromatics. These observations are discussed in relation to known Maillard chemistry. 37 refs., 8 figs., 1 tab.

  4. Fluoride-sensitivity of growth and acid production of oral Actinomyces: comparison with oral Streptococcus.

    Science.gov (United States)

    Kawashima, Junko; Nakajo, Kazuko; Washio, Jumpei; Mayanagi, Gen; Shimauchi, Hidetoshi; Takahashi, Nobuhiro

    2013-12-01

    Actinomyces are predominant oral bacteria; however, their cariogenic potential in terms of acid production and fluoride sensitivity has not been elucidated in detail and compared with that of other caries-associated oral bacteria, such as Streptococcus. Therefore, this study aimed to elucidate and compare the acid production and growth of Actinomyces and Streptococcus in the presence of bicarbonate and fluoride to mimic conditions in the oral cavity. Acid production from glucose was measured by pH-stat at pH 5.5 and 7.0 under anaerobic conditions. Growth rate was assessed by optical density in anaerobic culture. Although Actinomyces produced acid at a lower rate than did Streptococcus, their acid production was more tolerant of fluoride (IDacid production 50 = 110-170 ppm at pH 7.0 and 10-13 ppm at pH 5.5) than that of Streptococcus (IDacid production 50 = 36-53 ppm at pH 7.0 and 6.3-6.5 ppm at pH 5.5). Bicarbonate increased acid production by Actinomyces with prominent succinate production and enhanced their fluoride tolerance (IDacid production 50 = 220-320 ppm at pH 7.0 and 33-52 ppm at pH 5.5). Bicarbonate had no effect on these variables in Streptococcus. In addition, although the growth rate of Actinomyces was lower than that of Streptococcus, Actinomyces growth was more tolerant of fluoride (IDgrowth 50 = 130-160 ppm) than was that of Streptococcus (IDgrowth 50 = 27-36 ppm). These results indicate that oral Actinomyces are more tolerant of fluoride than oral Streptococcus, and bicarbonate enhances the fluoride tolerance of oral Actinomyces. Because of the limited number of species tested here, further study is needed to generalize these findings to the genus level.

  5. Comparison of low fat and low carbohydrate diets on circulating fatty acid composition and markers of inflammation.

    Science.gov (United States)

    Forsythe, Cassandra E; Phinney, Stephen D; Fernandez, Maria Luz; Quann, Erin E; Wood, Richard J; Bibus, Doug M; Kraemer, William J; Feinman, Richard D; Volek, Jeff S

    2008-01-01

    Abnormal distribution of plasma fatty acids and increased inflammation are prominent features of metabolic syndrome. We tested whether these components of metabolic syndrome, like dyslipidemia and glycemia, are responsive to carbohydrate restriction. Overweight men and women with atherogenic dyslipidemia consumed ad libitum diets very low in carbohydrate (VLCKD) (1504 kcal:%CHO:fat:protein = 12:59:28) or low in fat (LFD) (1478 kcal:%CHO:fat:protein = 56:24:20) for 12 weeks. In comparison to the LFD, the VLCKD resulted in an increased proportion of serum total n-6 PUFA, mainly attributed to a marked increase in arachidonate (20:4n-6), while its biosynthetic metabolic intermediates were decreased. The n-6/n-3 and arachidonic/eicosapentaenoic acid ratio also increased sharply. Total saturated fatty acids and 16:1n-7 were consistently decreased following the VLCKD. Both diets significantly decreased the concentration of several serum inflammatory markers, but there was an overall greater anti-inflammatory effect associated with the VLCKD, as evidenced by greater decreases in TNF-alpha, IL-6, IL-8, MCP-1, E-selectin, I-CAM, and PAI-1. Increased 20:4n-6 and the ratios of 20:4n-6/20:5n-3 and n-6/n-3 are commonly viewed as pro-inflammatory, but unexpectedly were consistently inversely associated with responses in inflammatory proteins. In summary, a very low carbohydrate diet resulted in profound alterations in fatty acid composition and reduced inflammation compared to a low fat diet.

  6. Comparison of nitrogen narcosis and helium pressure effects on striatal amino acids: a microdialysis study in rats.

    Science.gov (United States)

    Vallée, Nicolas; Rostain, Jean-Claude; Boussuges, Alain; Risso, Jean-Jacques

    2009-05-01

    Exposure to nitrogen-oxygen mixture at high pressure induces narcosis, which can be considered as a first step toward general anaesthesia. Narcotic potencies of inert gases are attributed to their lipid solubility. Nitrogen narcosis induces cognitive and motor disturbances that occur from 0.3 MPa in man and from 1 MPa in rats. Neurochemical studies performed in rats up to 3 MPa have shown that nitrogen pressure decreases striatal dopamine release like argon, another inert gas, or nitrous oxide, an anaesthetic gas. Striatal dopamine release is under glutamatergic and other amino acid neurotransmission regulations. The aim of this work was to study the effects of nitrogen at 3 MPa on striatal amino acid levels and to compare to those of 3 MPa of helium which is not narcotic at this pressure, by using a new technique of microdialysis samples extraction under hyperbaric conditions, in freely moving rats. Amino acids were analysed by HPLC coupled to fluorimetric detection in order to appreciate glutamate, aspartate, glutamine and asparagine levels. Nitrogen-oxygen mixture exposure at 3 MPa decreased glutamate, glutamine and asparagine concentrations. In contrast, with helium-oxygen mixture, glutamate and aspartate levels were increased during the compression phase but not during the stay at maximal pressure. Comparison between nitrogen and helium highlighted the narcotic effects of nitrogen at pressure. As a matter of fact, nitrogen induces a reduction in glutamate and in other amino acids that could partly explain the decrease in striatal dopamine level as well as the motor and cognitive disturbances reported in nitrogen narcosis.

  7. Direct infusion electrospray ionization–ion mobility–mass spectrometry for comparative profiling of fatty acids based on stable isotope labeling

    Energy Technology Data Exchange (ETDEWEB)

    Leng, Jiapeng, E-mail: jpleng@126.com [Department of Chemical Engineering, North University of China, Taiyuan 030051 (China); Guan, Qing [Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center (FUSCC), Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Sun, Tuanqi, E-mail: tuanqisun@163.com [Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center (FUSCC), Shanghai 200032 (China); Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Wang, Haoyang [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 (China); Cui, Jianlan; Liu, Qinghao [Department of Chemical Engineering, North University of China, Taiyuan 030051 (China); Zhang, Zhixu; Zhang, Manyu [Agilent Technologies China Co., Ltd, Shanghai 200080 (China); Guo, Yinlong, E-mail: ylguo@sioc.ac.cn [National Center for Organic Mass Spectrometry in Shanghai, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai 200032 (China)

    2015-08-05

    A rapid method for fatty acids (FAs) comparative profiling based on carboxyl-specific stable isotope labeling (SIL) and direct infusion electrospray ionization–ion mobility–mass spectrometry (ESI–IM–MS) is established. The design of the method takes advantage of the three-dimensional characteristics of IM–MS including drift time, m/z and ion intensity, for comparison of d0-/d6-2,4-dimethoxy-6-piperazin-1-yl pyrimidine (DMPP)-labeled FAs. In particular, without chromatographic separation, the method allowed direct FAs profiling in complex samples due to the advantageous priority of DMPP in signal enhancement as well as the extra resolution that IM–MS offered. Additionally, the d0-/d6-DMPP-labeled FAs showed expected features, including very similar drift times, 6 Da mass deviations, specific reporter ions, similar MS responses, and adherence to the drift time rule regarding the influence of carbon chain length and unsaturation on relative drift times. Therefore, the introduction of isotope analogs minimized the matrix effect and variations in quantification and ensured accurate identification of non-targeted FAs by those typical features. Peak intensity ratios between d0-/d6-DMPP-labeled ions were subsequently used in relative quantification for the detected FAs. The established strategy has been applied successfully in the rapid profiling of trace free FAs between normal and cancerous human thyroid tissues. Sixteen free FAs were found with the increased level with a statistically significant difference (p < 0.05) compared to the normal tissue samples. The integrated SIL technique and ESI–IM–MS are expected to serve as an alternative tool for high-throughput analysis of FAs in complex samples. - Highlights: • A novel method based on IM–MS and SIL was developed for FAs comparative profiling. • Without LC separation, the method allowed direct infusion profiling of FAs in complex samples. • Both of the efficiency and accuracy for FAs analyses

  8. Comparison of the Morphology and Deoxyribonucleic Acid Composition of 27 Strains of Nitrifying Bacteria1

    Science.gov (United States)

    Watson, Stanley W.; Mandel, Manley

    1971-01-01

    The gross morphology, fine structure, and per cent guanine plus cytosine (GC) composition of deoxyribonucleic acid of 27 strains of nitrifying bacteria were compared. Based on morphological differences, the ammonia-oxidizing bacteria were separated into four genera. Nitrosomonas species and Nitrosocystis species formed one homogenous group, and Nitrosolobus species and Nitrosospira species formed a second homogenous group in respect to their deoxyribonucleic acid GC compositions. Similarly, the nitrite-oxidizing bacteria were separated into three genera based on their morphology. The members of two of these nitrite-oxidizing genera, Nitrobacter and Nitrococcus, had similar GC compositions, but Nitrospina gracilis had a significantly lower GC composition than the members of the other two genera. Images PMID:4939767

  9. Comparison of the morphology and deoxyribonucleic acid composition of 27 strains of nitrifying bacteria.

    Science.gov (United States)

    Watson, S W; Mandel, M

    1971-08-01

    The gross morphology, fine structure, and per cent guanine plus cytosine (GC) composition of deoxyribonucleic acid of 27 strains of nitrifying bacteria were compared. Based on morphological differences, the ammonia-oxidizing bacteria were separated into four genera. Nitrosomonas species and Nitrosocystis species formed one homogenous group, and Nitrosolobus species and Nitrosospira species formed a second homogenous group in respect to their deoxyribonucleic acid GC compositions. Similarly, the nitrite-oxidizing bacteria were separated into three genera based on their morphology. The members of two of these nitrite-oxidizing genera, Nitrobacter and Nitrococcus, had similar GC compositions, but Nitrospina gracilis had a significantly lower GC composition than the members of the other two genera.

  10. Comparison of Three Nucleic Acid Amplification Assays of Cerebrospinal Fluid for Diagnosis of Cytomegalovirus Encephalitis

    Science.gov (United States)

    Bestetti, Arabella; Pierotti, Chiara; Terreni, Mariarosa; Zappa, Alessandra; Vago, Luca; Lazzarin, Adriano; Cinque, Paola

    2001-01-01

    The diagnostic reliabilities of three cytomegalovirus (CMV) nucleic acid amplification assays of cerebrospinal fluid (CSF) were compared by using CSF samples from human immunodeficiency virus-infected patients with a postmortem histopathological diagnosis of CMV encephalitis (n = 15) or other central nervous system conditions (n = 16). By using a nested PCR assay, the quantitative COBAS AMPLICOR CMV MONITOR PCR, and the NucliSens CMV pp67 nucleic acid sequence-based amplification assay, sensitivities were 93.3, 86.6, and 93.3%, respectively, and specificities were 93.7, 93.7, and 87.5%, respectively. The COBAS AMPLICOR assay revealed significantly higher CMV DNA levels in patients with diffuse ventriculoencephalitis than in patients with focal periventricular lesions. PMID:11230445

  11. Comparison of Xe single bubble sonoluminescence in water and sulfuric acid

    Institute of Scientific and Technical Information of China (English)

    An Yu

    2008-01-01

    Using the equations of fluid mechanics with proper boundary conditions and taking account of the gas properties, we can numerically simulate the process of single bubble sonoluminescence, in which electron-neutral atom bremsstrahlung, electron-ion bremsstrahlung and recombination radiation, and the radiative attachment of electrons to atoms and molecules contribute to the light emission. The calculation can quantitatively or qualitatively interpret the experimental results. We find that the accumulated heat energy inside the compressed gas bubble is mostly consumed by the chemical reaction, therefore, the maximum degree of ionization inside Xe bubble in water is much lower than that in sulfuric acid, of which the vapour pressure is very low. In addition, in sulfuric acid much larger pa and R0 are allowed which makes the bubbles in it much brighter than that in water.

  12. Inhibitors from carob (Ceratonia siliqua L.) : III. Comparisons with abscisic acid.

    Science.gov (United States)

    Corcoran, M R

    1970-06-01

    Inhibitory extracts of carob and abscisic acid (ABA) were compared and found to behave differently in three types of tests. The carob inhibitors remained at the origin upon thin-layer chromatography in two different solvent systems while a cis-trans mixture of ABA had Rf's of 2.5 and 3.5 in the first system (chloroform:acetic acid, 95:5), and 3.5 and 4.5 in the second system (benzene:acetic acid:water, 8:3:5). When ABA and carob extract were mixed and then chromatographed, the ABA had the same Rf values as ABA chromatographed alone.Assays utilizing light-grown, dwarf peas showed that a weight ratio of 1000: 1 ABA:gibberellic acid (GA3) was necessary to inhibit GA3-induced growth by 50% while carob fraction C is inhibitory to GA3 at a ratio of 17:1. The amount of ABA which inhibited 50% of the growth induced by 0.05 μg GA3 reduced the endogenous growth of both dwarf and non-dwarf pea seedlings; in contrast, concentrations of carob extract up to 100 times greater than the amount necessary for 50% inhibition of the growth response caused by 0.05 μg GA3 did not affect endogenous growth.Only very small amounts of inhibitory activity from carob extract were transferred from water to chloroform at a pH (2.0) at which most of the ABA was transferred.

  13. An inter-laboratory comparison of urinary 3-hydroxypropylmercapturic acid measurement demonstrates good reproducibility between laboratories

    Directory of Open Access Journals (Sweden)

    Bailey Brian

    2011-10-01

    Full Text Available Abstract Background Biomarkers have been used extensively in clinical studies to assess toxicant exposure in smokers and non-smokers and have recently been used in the evaluation of novel tobacco products. The urinary metabolite 3-HPMA, a metabolite of the major tobacco smoke toxicity contributor acrolein, is one example of a biomarker used to measure exposure to tobacco smoke. A number of laboratories have developed liquid chromatography with tandem mass spectrometry (LC-MS/MS based methods to measure urinary 3-HPMA; however, it is unclear to what extent the data obtained by these different laboratories are comparable. Findings This report describes an inter-laboratory comparison carried out to evaluate the comparability of 3-HPMA measurement between four laboratories. A common set of spiked and authentic smoker and non-smoker urine samples were used. Each laboratory used their in-house LC-MS/MS method and a common internal standard. A comparison of the repeatability ('r', reproducibility ('R', and coefficient of variation for 3-HPMA demonstrated that within-laboratory variation was consistently lower than between-laboratory variation. The average inter-laboratory coefficient of variation was 7% for fortified urine samples and 16.2% for authentic urine samples. Together, this represents an inter-laboratory variation of 12.2%. Conclusion The results from this first inter-laboratory comparison for the measurement of 3-HPMA in urine demonstrate a reasonably good consensus between laboratories. However, some consistent measurement biases were still observed between laboratories, suggesting that additional work may be required to further reduce the inter-laboratory coefficient of variation.

  14. Comparison of homo- and heterofermentative lactic acid bacteria for implementation of fermented wheat bran in bread.

    Science.gov (United States)

    Prückler, Michael; Lorenz, Cindy; Endo, Akihito; Kraler, Manuel; Dürrschmid, Klaus; Hendriks, Karel; Soares da Silva, Francisco; Auterith, Eric; Kneifel, Wolfgang; Michlmayr, Herbert

    2015-08-01

    Despite its potential health benefits, the integration of wheat bran into the food sector is difficult due to several adverse technological and sensory properties such as bitterness and grittiness. Sourdough fermentation is a promising strategy to improve the sensory quality of bran without inducing severe changes to the bran matrix. Therefore, identification of species/strains with potential for industrial sourdough fermentations is important. We compared the effects of different representatives of species of lactic acid bacteria (LAB) on wheat bran. Lactobacillus plantarum, Lactobacillus pentosus, Lactobacillus brevis, Lactobacillus sanfranciscensis and Fructobacillus fructosus produced highly individual fermentation patterns as judged from carbohydrate consumption and organic acid production. Interestingly, fructose was released during all bran fermentations and possibly influenced the fermentation profiles of obligately heterofermentative species to varying degrees. Except for the reduction of ferulic acid by L. plantarum and L. pentosus, analyses of phenolic compounds and alkylresorcinols suggested that only minor changes thereof were induced by the LAB metabolism. Sensory analysis of breads baked with fermented bran did not reveal significant differences regarding perceived bitterness and aftertaste. We conclude that in addition to more traditionally used sourdough species such as L. sanfranciscensis and L. brevis, also facultatively heterofermentative species such as L. plantarum and L. pentosus possess potential for industrial wheat bran fermentations and should be considered in further investigations.

  15. Comparison of microwave oven and convection oven for acid hydrolysis of dietary fiber polysaccharides.

    Science.gov (United States)

    Li, B W

    1998-01-01

    Hydrolysis of dietary fiber polysaccharides (DFP) is an integral part of any enzymatic-chemical method for dietary fiber analysis. Residues obtained after enzyme treatments of fiber-containing foods are usually suspended in 12 M sulfuric acid and kept at or slightly above ambient temperature for at least 1 h, and then the mixtures are diluted with deionized water to a final concentration of 1 M or 2 M acid, followed by heating at 100 degrees C in a water bath or convection oven for 1 or 2 h. Under these hydrolytic conditions, some degradation of the released monosaccharides generally takes place over the duration of hydrolysis. We investigated the feasibility of using microwave energy as a heat source to reduce time and minimize degradation. Preliminary tests were done on the well-characterized soy polysaccharide Fibrim. With a microwave digestion system equipped with temperature and pressure monitors and control lines, optimum settings of power (5%, 75%), time (up to 3 min and 30 s), temperature (35 degrees-55 degrees C), and pressure (45-65 psi) were determined for different foods depending on the residue weight and volume of acid. Results were comparable for microwave oven and convection oven hydrolysis of DFP from 5 foods with good correlations for neutral sugar values; r2 = 0.997 for arabinose, 0.925 for galactose, 0.981 for glucose, 0.969 for mannose, and 0.990 for xylose.

  16. COMPARISON OF BIODIESEL PRODUCTIVITIES OF DIFFERENT VEGETABLE OILS BY ACIDIC CATALYSIS

    Directory of Open Access Journals (Sweden)

    AYTEN SAGIROGLU

    2011-03-01

    Full Text Available Biodiesel has become a subject which increasingly attracts worldwide attention because of its environmental benefits, biodegradability and renewability. Biodiesel production typically involves the transesterification of a triglyceride feedstock with methanol or other short-chain alcohols. This paper presents a study of transesterification of various vegetable oils, sunflower, safflower, canola, soybean, olive, corn, hazelnut and waste sunflower oils, with the acidic catalyst. Under laboratory conditions, fatty acid methyl esters (FAME were prepared by using methanol in the presence of 1.85% hydrochloric acid at 100 °C for 1 h and 25 °C for 3 h. The analyses of biodiesel were carried out by gas chroma¬tography and thin layer chromatography. Also, biodiesel productivities (% were determined on basis of the ratio of ester to oil content (w/w. The biodiesel productivities for all oils were found to be about 80% and about 90% at 25 and 100 °C, respectively. Also, the results showed that the yield of biodiesel depended on temperature for some oils, including canola, sunflower, safflower oils, but it was not found significant differences among all of the oil types on biodiesel productivities.

  17. Comparison of femtosecond laser and continuous wave UV sources for protein-nucleic acid crosslinking.

    Science.gov (United States)

    Fecko, Christopher J; Munson, Katherine M; Saunders, Abbie; Sun, Guangxing; Begley, Tadhg P; Lis, John T; Webb, Watt W

    2007-01-01

    Crosslinking proteins to the nucleic acids they bind affords stable access to otherwise transient regulatory interactions. Photochemical crosslinking provides an attractive alternative to formaldehyde-based protocols, but irradiation with conventional UV sources typically yields inadequate product amounts. Crosslinking with pulsed UV lasers has been heralded as a revolutionary technique to increase photochemical yield, but this method had only been tested on a few protein-nucleic acid complexes. To test the generality of the yield enhancement, we have investigated the benefits of using approximately 150 fs UV pulses to crosslink TATA-binding protein, glucocorticoid receptor and heat shock factor to oligonucleotides in vitro. For these proteins, we find that the quantum yields (and saturating yields) for forming crosslinks using the high-peak intensity femtosecond laser do not improve on those obtained with low-intensity continuous wave (CW) UV sources. The photodamage to the oligonucleotides and proteins also has comparable quantum yields. Measurements of the photochemical reaction yields of several small molecules selected to model the crosslinking reactions also exhibit nearly linear dependences on UV intensity instead of the previously predicted quadratic dependence. Unfortunately, these results disprove earlier assertions that femtosecond pulsed laser sources provide significant advantages over CW radiation for protein-nucleic acid crosslinking.

  18. Chronic fluoxetine treatment directs energy metabolism towards the citric acid cycle and oxidative phosphorylation in rat hippocampal nonsynaptic mitochondria.

    Science.gov (United States)

    Filipović, Dragana; Costina, Victor; Perić, Ivana; Stanisavljević, Andrijana; Findeisen, Peter

    2017-03-15

    Fluoxetine (Flx) is the principal treatment for depression; however, the precise mechanisms of its actions remain elusive. Our aim was to identify protein expression changes within rat hippocampus regulated by chronic Flx treatment versus vehicle-controls using proteomics. Fluoxetine-hydrohloride (15mg/kg) was administered daily to adult male Wistar rats for 3weeks, and cytosolic and nonsynaptic mitochondrial hippocampal proteomes were analyzed. All differentially expressed proteins were functionally annotated according to biological process and molecular function using Uniprot and Blast2GO. Our comparative study revealed that in cytosolic and nonsynaptic mitochondrial fractions, 60 and 3 proteins respectively, were down-regulated, and 23 and 60 proteins, respectively, were up-regulated. Proteins differentially regulated in cytosolic and nonsynaptic mitochondrial fractions were primarily related to cellular and metabolic processes. Of the identified proteins, the expressions of calretinin and parvalbumine were confirmed. The predominant molecular functions of differentially expressed proteins in both cell hippocampal fractions were binding and catalytic activity. Most differentially expressed proteins in nonsynaptic mitochondria were catalytic enzymes involved in the pyruvate metabolism, citric acid cycle, oxidative phosphorylation, ATP synthesis, ATP transduction and glutamate metabolism. Results indicate that chronic Flx treatment may influence proteins involved in calcium signaling, cytoskeletal structure, chaperone system and stimulates energy metabolism via the upregulation of GAPDH expression in cytoplasm, as well as directing energy metabolism toward the citric acid cycle and oxidative phosphorylation in nonsynaptic mitochondria. This approach provides new insight into the chronic effects of Flx treatment on protein expression in a key brain region associated with stress response and memory.

  19. Site-directed mutagenesis of HgcA and HgcB reveals amino acid residues important for mercury methylation.

    Science.gov (United States)

    Smith, Steven D; Bridou, Romain; Johs, Alexander; Parks, Jerry M; Elias, Dwayne A; Hurt, Richard A; Brown, Steven D; Podar, Mircea; Wall, Judy D

    2015-05-01

    Methylmercury is a potent neurotoxin that is produced by anaerobic microorganisms from inorganic mercury by a recently discovered pathway. A two-gene cluster, consisting of hgcA and hgcB, encodes two of the proteins essential for this activity. hgcA encodes a corrinoid protein with a strictly conserved cysteine proposed to be the ligand for cobalt in the corrinoid cofactor, whereas hgcB encodes a ferredoxin-like protein thought to be an electron donor to HgcA. Deletion of either gene eliminates mercury methylation by the methylator Desulfovibrio desulfuricans ND132. Here, site-directed mutants of HgcA and HgcB were constructed to determine amino acid residues essential for mercury methylation. Mutations of the strictly conserved residue Cys93 in HgcA, the proposed ligand for the corrinoid cobalt, to Ala or Thr completely abolished the methylation capacity, but a His substitution produced measurable methylmercury. Mutations of conserved amino acids near Cys93 had various impacts on the methylation capacity but showed that the structure of the putative "cap helix" region harboring Cys93 is crucial for methylation function. In the ferredoxin-like protein HgcB, only one of two conserved cysteines found at the C terminus was necessary for methylation, but either cysteine sufficed. An additional, strictly conserved cysteine, Cys73, was also determined to be essential for methylation. This study supports the previously predicted importance of Cys93 in HgcA for methylation of mercury and reveals additional residues in HgcA and HgcB that facilitate the production of this neurotoxin.

  20. Poly(lactic acid)-poly(ethylene oxide) block copolymers: new directions in self-assembly and biomedical applications.

    Science.gov (United States)

    Saffer, E M; Tew, G N; Bhatia, S R

    2011-01-01

    In this review, we focus on recent developments in biomaterials of poly(lactic acid)-poly(ethylene oxide)-poly(lactic acid) (PLA-PEO-PLA) triblock copolymers. This system has been widely explored for a number of applications in controlled and sustained release of drugs and in tissue engineering devices. New insights into self-assembly of these materials have resulted in new PLA-PEOPLA solutions and gels with novel structural, mechanical, and drug release properties. Recent innovations include hydrogels with nanoscale crystalline domains, solutions and gels based on PLA stereocomplexes, and nanoparticle-copolymer assemblies. We first briefly review synthetic approaches to these materials. We then describe characterization of the solution properties, formation of micelles, drug release characteristics, and investigation of the sol-gel transition. The properties of PLA-PEO-PLA hydrogels are then discussed, including the effect of crystalline domains on the gel microstructure and efforts to tune the elastic modulus and degredation properties of gels through the addition of chemical crosslinks. In the second half of the review, we discuss the wide variety of biomedical applications currently being pursued for PLA-PEO-PLA triblock copolymer systems. Polymer-nanoparticle complexes have been investigated to facilitate the formation of metal nanoclusters used as biosensors, as well as to enhance the elastic modulus of hydrogels. Thin polymer films have also been investigated for use as tissue engineering scaffolds and as drug-eluding coatings for stents and other medical implants. Finally, we discuss future directions for biomedical applications of this system, including new strategies for improving the specificity and cell affinity of PLA-based biomaterials.

  1. Comparison of the acid-base properties of ribose and 2'-deoxyribose nucleotides.

    Science.gov (United States)

    Mucha, Ariel; Knobloch, Bernd; Jezowska-Bojczuk, Małgorzata; Kozłowski, Henryk; Sigel, Roland K O

    2008-01-01

    The extent to which the replacement of a ribose unit by a 2'-deoxyribose unit influences the acid-base properties of nucleotides has not hitherto been determined in detail. In this study, by potentiometric pH titrations in aqueous solution, we have measured the acidity constants of the 5'-di- and 5'-triphosphates of 2'-deoxyguanosine [i.e., of H(2)(dGDP)(-) and H(2)(dGTP)(2-)] as well as of the 5'-mono-, 5'-di-, and 5'-triphosphates of 2'-deoxyadenosine [i.e., of H(2)(dAMP)(+/-), H(2)(dADP)(-), and H(2)(dATP)(2-)]. These 12 acidity constants (of the 56 that are listed) are compared with those of the corresponding ribose derivatives (published data) measured under the same experimental conditions. The results show that all protonation sites in the 2'-deoxynucleotides are more basic than those in their ribose counterparts. The influence of the 2'-OH group is dependent on the number of 5'-phosphate groups as well as on the nature of the purine nucleobase. The basicity of N7 in guanine nucleotides is most significantly enhanced (by about 0.2 pK units), while the effect on the phosphate groups and the N1H or N1H(+) sites is less pronounced but clearly present. In addition, (1)H NMR chemical shift change studies in dependence on pD in D(2)O have been carried out for the dAMP, dADP, and dATP systems, which confirmed the results from the potentiometric pH titrations and showed the nucleotides to be in their anti conformations. Overall, our results are not only of relevance for metal ion binding to nucleotides or nucleic acids, but also constitute an exact basis for the calculation, determination, and understanding of perturbed pK(a) values in DNAzymes and ribozymes, as needed for the delineation of acid-base mechanisms in catalysis.

  2. Comparison of gravimetric, creamatocrit and esterified fatty acid methods for determination of total fat content in human milk.

    Science.gov (United States)

    Du, Jian; Gay, Melvin C L; Lai, Ching Tat; Trengove, Robert D; Hartmann, Peter E; Geddes, Donna T

    2017-02-15

    The gravimetric method is considered the gold standard for measuring the fat content of human milk. However, it is labor intensive and requires large volumes of human milk. Other methods, such as creamatocrit and esterified fatty acid assay (EFA), have also been used widely in fat analysis. However, these methods have not been compared concurrently with the gravimetric method. Comparison of the three methods was conducted with human milk of varying fat content. Correlations between these methods were high (r(2)=0.99). Statistical differences (Pmilk) using the three methods. Overall, stronger correlation with lower mean (4.73g/L) and percentage differences (5.16%) was observed with the creamatocrit than the EFA method when compared to the gravimetric method. Furthermore, the ease of operation and real-time analysis make the creamatocrit method preferable.

  3. Genetic Incorporation of the Unnatural Amino Acid p-Acetyl Phenylalanine into Proteins for Site-Directed Spin Labeling

    Science.gov (United States)

    Evans, Eric G.B.; Millhauser, Glenn L.

    2016-01-01

    Site-directed spin labeling (SDSL) is a powerful tool for the characterization of protein structure and dynamics; however, its application in many systems is hampered by the reliance on unique and benign cysteine substitutions for the site-specific attachment of the spin label. An elegant solution to this problem involves the use of genetically encoded unnatural amino acids (UAAs) containing reactive functional groups that are chemically orthogonal to those of the 20 amino acids found naturally in proteins. These unique functional groups can then be selectively reacted with an appropriately functionalized spin probe. In this chapter, we detail the genetic incorporation of the ketone-bearing amino acid p-acetyl phenylalanine (pAcPhe) into recombinant proteins expressed in E. coli. Incorporation of pAcPhe is followed by chemoselective reaction of the ketone side chain with a hydroxylamine-functionalized nitroxide to afford the spin-labeled side chain “K1,” and we present two protocols for successful K1 labeling of proteins bearing site-specific pAcPhe. We outline the basic requirements for pAcPhe incorporation and labeling, with an emphasis on practical aspects that must be considered by the researcher if high yields of UAA incorporation and efficient labeling reactions are to be achieved. To this end, we highlight recent advances that have led to increased yields of pAcPhe incorporation, and discuss the use of aniline-based catalysts allowing for facile conjugation of the hydroxylamine spin label under mild reaction conditions. To illustrate the utility of K1 labeling in proteins where traditional cysteine-based SDSL methods are problematic, we site-specifically K1 label the cellular prion protein at two positions in the C-terminal domain and determine the interspin distance using double electron–electron resonance EPR. Recent advances in UAA incorporation and ketone-based bioconjugation, in combination with the commercial availability of all requisite

  4. Genetic Incorporation of the Unnatural Amino Acid p-Acetyl Phenylalanine into Proteins for Site-Directed Spin Labeling.

    Science.gov (United States)

    Evans, Eric G B; Millhauser, Glenn L

    2015-01-01

    Site-directed spin labeling (SDSL) is a powerful tool for the characterization of protein structure and dynamics; however, its application in many systems is hampered by the reliance on unique and benign cysteine substitutions for the site-specific attachment of the spin label. An elegant solution to this problem involves the use of genetically encoded unnatural amino acids (UAAs) containing reactive functional groups that are chemically orthogonal to those of the 20 amino acids found naturally in proteins. These unique functional groups can then be selectively reacted with an appropriately functionalized spin probe. In this chapter, we detail the genetic incorporation of the ketone-bearing amino acid p-acetyl phenylalanine (pAcPhe) into recombinant proteins expressed in E. coli. Incorporation of pAcPhe is followed by chemoselective reaction of the ketone side chain with a hydroxylamine-functionalized nitroxide to afford the spin-labeled side chain "K1," and we present two protocols for successful K1 labeling of proteins bearing site-specific pAcPhe. We outline the basic requirements for pAcPhe incorporation and labeling, with an emphasis on practical aspects that must be considered by the researcher if high yields of UAA incorporation and efficient labeling reactions are to be achieved. To this end, we highlight recent advances that have led to increased yields of pAcPhe incorporation, and discuss the use of aniline-based catalysts allowing for facile conjugation of the hydroxylamine spin label under mild reaction conditions. To illustrate the utility of K1 labeling in proteins where traditional cysteine-based SDSL methods are problematic, we site-specifically K1 label the cellular prion protein at two positions in the C-terminal domain and determine the interspin distance using double electron-electron resonance EPR. Recent advances in UAA incorporation and ketone-based bioconjugation, in combination with the commercial availability of all requisite reagents

  5. Comparison of Genetic Parameters Estimation of Fatty Acids from Gas Chromatography and FT-IR in Holsteins

    DEFF Research Database (Denmark)

    Poulsen, Nina Aagaard; Eskildsen, C E A; Skov, Thomas;

    Fourier transform infrared (FT-IR) is routinely used in the milk recording system and IR-based solutions are therefore attractive to ensure the full potential of genomic selection data in future breeding programs. Today, IR-based models can be used to predict a wide range of milk traits......, and their genetic parameters. However, IR-predicted phenotypes for detailed milk composition are often based on their correlation to other traits in a given data set rather than on direct predictions. Here, genetic parameters for individual milk fatty acids were estimated based on either IR-predicted phenotypes...

  6. Direct observation of the cyclic dimer in liquid acetic acid by probing the C=O vibration with ultrafast coherent Raman spectroscopy.

    Science.gov (United States)

    Lütgens, Matthias; Friedriszik, Frank; Lochbrunner, Stefan

    2014-09-01

    We present a comparison of spontaneous Raman and ultrafast coherent anti-Stokes Raman scattering (CARS) spectra of the C=O vibration of liquid acetic acid. The former technique cannot clearly reveal the number of contributions in the spectrum. However, the additional time and spectrally resolved CARS experiment supports strictly the existence of four modes, which proves the coexistence of more than one H-bonded configuration in liquid acetic acid. A comparably slowly dephasing mode which is obscured by a broad band in the linear Raman spectrum is assigned to the cyclic dimer and can be observed freed from all other contributions by ultrafast CARS.

  7. Comparison of simulated forest soil response to acid deposition reduction with two models of differing complexity

    Directory of Open Access Journals (Sweden)

    J. P. Mol-Dijkstra

    1998-01-01

    Full Text Available Great effort has been dedicated to developing soil acidification models for use on different scales. This paper focuses on the changes in model performance of a site scale soil acidification model (NUCSAM and a national to European scale soil acidification model (SMART 2. This was done to gain insight into the effects of model simplification. Because these models aim to predict the response to reduction in acid deposition, these models must be tested under such circumstances. A straightforward calibration and validation of the regional model, however, is hampered by lack of observations over a sufficient time period. Consequently, NUCSAM was calibrated and validated to a manipulation experiment involving reduced acid deposition in the Speuld forest, the Netherlands. SMART 2 was then used with calibrated input data from NUCSAM. The acid deposition was excluded by a roof beneath the canopy. The roofed area consists of a plot receiving pristine deposition levels of nitrogen (N and sulphur (S and a control plot receiving ambient deposition. NUCSAM was calibrated on the ambient plot, followed by a validation of both models on the pristine plot. Both models predicted soil solution concentrations within the 95% confidence interval of the observed responses for both the ambient plot and the pristine plot at 90 cm depth. Despite the large seasonal and vertical (spatial variation in soil solution chemistry, the trends in annual flux- weighted soil solution chemistry, as predicted by SMART 2 and NUCSAM, corresponded well.The annual leaching fluxes below the root zone were also similar although differences exist for the topsoil. For the topsoil, NUCSAM simulated the nutrients and acid related constituents better than SMART 2. Both models overestimated the ammonium (NH4 concentration at 10 cm depth. SMART 2 underestimated calcium and magnesium (BC2+ concentration at 10 depth, whereas NUCSAM overestimated BC2+ concentration at 90 cm depth. NUCSAM predicted

  8. Nonlocal nonlinear refractive index of gold nanoparticles synthesized by ascorbic acid reduction: comparison of fitting models.

    Science.gov (United States)

    Balbuena Ortega, A; Arroyo Carrasco, M L; Méndez Otero, M M; Gayou, V L; Delgado Macuil, R; Martínez Gutiérrez, H; Iturbe Castillo, M D

    2014-12-12

    In this paper, the nonlinear refractive index of colloidal gold nanoparticles under continuous wave illumination is investigated with the z-scan technique. Gold nanoparticles were synthesized using ascorbic acid as reductant, phosphates as stabilizer and cetyltrimethylammonium chloride (CTAC) as surfactant agent. The nanoparticle size was controlled with the CTAC concentration. Experiments changing incident power and sample concentration were done. The experimental z-scan results were fitted with three models: thermal lens, aberrant thermal lens and the nonlocal model. It is shown that the nonlocal model reproduces with exceptionally good agreement; the obtained experimental behaviour.

  9. Inactivation model equations and their associated parameter values obtained under static acid stress conditions cannot be used directly for predicting inactivation under dynamic conditions.

    Science.gov (United States)

    Janssen, M; Verhulst, A; Valdramidis, V; Devlieghere, F; Van Impe, J F; Geeraerd, A H

    2008-11-30

    Organic acids (e.g., lactic acid, acetic acid and citric acid) are popular preservatives. In this study, the Listeria innocua inactivation is investigated under dynamic conditions of pH and undissociated lactic acid ([LaH]). A combined primary (Weibull-type) and secondary model developed for the L. innocua inactivation under static conditions [Janssen, M., Geeraerd, A.H., Cappuyns, A., Garcia-Gonzalez, L., Schockaert, G., Van Houteghem, N., Vereecken, K.M., Debevere, J., Devlieghere, F., Van Impe, J.F., 2007. Individual and combined effects of pH and lactic acid concentration on L. innocua inactivation: development of a predictive model and assessment of experimental variability. Applied and Environmental Microbiology 73(5), 1601-1611] was applied to predict the microbial inactivation under dynamic conditions. Because of its non-autonomous character, two approaches were proposed for the application of the Weibull-type model to dynamic conditions. The results quantitatively indicated that the L. innocua cell population was able to develop an induced acid stress resistance under dynamic conditions of pH and [LaH]. From a modeling point of view, it needs to be stressed that (i) inactivation model equations and associated parameter values, derived under static conditions, may not be suitable for use as such under dynamic conditions, and (ii) non-autonomous dynamic models reveal additional technical intricacies in comparison with autonomous models.

  10. Drug release behavior of poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA) prepared by direct polycondensation.

    Science.gov (United States)

    Shi, Gang; Ding, Yuanyuan; Zhang, Xin; Wu, Luyan; He, Fei; Ni, Caihua

    2015-01-01

    Hydrophobically modified sodium alginate, poly (lactic-glycolic acid) grafting from sodium alginate (ALG-g-PLGA), was successfully synthesized through direct one-step polymerization of sodium alginate, glycolic acid, and lactic acid. ALG-g-PLGA self-assembled to colloidal nanoparticles and subsequently hydrogel microspheres were obtained by crosslinking ALG-g-PLGA nanoparticles in the solution of calcium chloride. The modified hydrogel microspheres could be used as the drug delivery vehicles for a hydrophobic ibuprofen. Compared with sodium alginate, ALG-g-PLGA demonstrated an improved drug loading rate, encapsulation efficiency, and prolonged release speed. The products, as novel and highly promising biomaterials, have potential applications.

  11. Comparison of plasma uric acid levels in five varieties of the domestic turkey, Meleagris gallopavo.

    Science.gov (United States)

    Hartman, S; Taleb, S A; Geng, T; Gyenai, K; Guan, X; Smith, E

    2006-10-01

    Plasma uric acid (PUA) is a consensus physiological biomarker for many phenotypes in vertebrates because it is a reliable indicator for processes such as oxidative stress and tubular function. In birds, it is considered a major antioxidant and is also the primary endproduct of nitrogen metabolism. Despite this importance, knowledge of baseline levels of PUA in physiologically normal birds, including the turkey, Meleagris gallopavo, is limited. Here, we compared PUA levels in a total of 106 apparently normal male and female birds at 8 and 32 wk of age from 5 strains of the domestic turkey, including Bourbon Red, Narragansett, Blue Slate, Royal Palm, and Spanish Black. Though differences in PUA were not significant at 8 and 32 wk of age, BW, variety, and sex effects were highly significant. When adjusted for BW, female birds had, on average, a higher PUA per kilogram of BW than male birds. When adjusted for both sex and BW, Royal Palm birds had the lowest average PUA, and Blue Slate had the highest PUA. Results of these investigations represent the first comparative analysis of PUA in physiologically normal turkey varieties. They suggest that differences in basal plasma levels of uric acid in physiologically normal turkeys are influenced by sex, weight, and genetic background but may be independent of age.

  12. Comparison of Intravenous Ranitidine with Pantoprazole in Decreasing Gastric Fluid Acidity in Emergency Cesarean Section

    Directory of Open Access Journals (Sweden)

    Alipour M

    2013-10-01

    Full Text Available Objectives: Peri-operative aspiration of gastric contents is a problem that causes certain respiratory problems including ARDS. Prophylaxis against aspiration of gastric contents is performed routinely in elective surgeries, but there is rare evidence on the efficacy of this method in emergency cesarean section. Materials and Methods: This is a randomized, controlled, double-blinded clinical trial. 60 parturients undergoing emergency cesarean section were randomly assigned into three groups of 20 each. They were allocated into two study and one placebo groups. The study group one and two received intravenous ranitidine (IV 50 mg or IV pantoprazole 40 mg, half an hour before induction of GA, respectively. The placebo group was administered just 5 ml of isotonic saline half an hour before GA induction. After intubation and confirmation of endotracheal tube insertion, the gastric contents were aspirated through a nasogastric tube for evaluation of acidity and volume. Results: A statistical difference between group one and two with the control group was observed in the acidity of gastric contents, but there was no difference in volume. Also, the PH level of gastric contents in patients receiving pantoprazole was significantly higher than the isotonic saline (p

  13. Membrane crystallinity and fuel crossover in direct ethanol fuel cells with Nafion composite membranes containing phosphotungstic acid

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hongjun; Lee, Sunghwan; Kim, Suran; Oh, Chungik; Ryu, Jeongjae; Kim, Jaegyu; Park, Eugene; Hong, Seungbum; No, Kwangsoo

    2016-11-01

    Interest has been growing in direct ethanol fuel cells (DEFCs) due to their non-toxicity, low cost and potential contribution to energy issues in third world countries. A reduction in fuel cross-over is of key importance to enhance the performance of DEFCs that operate at low temperatures (<100 °C). We report on the effect of the addition of phosphotungstic acid (PWA) in Nafion membrane on the ethanol-crossover for DEFC application. A set of PWANafion composite membranes (PWA 0, 5, 10, 15, 20 wt%) was prepared by solution casting and their microstructures, diffraction patterns and permeability were systematically characterized. The significant reduction in ethanol-crossover was observed with increasing PWA concentration in PWA-Nafion membranes, which was mainly attributed to an improvement in crystallinity of the membrane. PWA provides additional nucleation sites during solidification leading to higher crystallinity, which is supported by the membrane permeability tests. These PWA-Nafion composites were implemented in proto-type DEFC devices as a membrane and the maximum power density achieved was 22% higher than that of commercial Nafion-117 device.

  14. Bioceramic/Poly (glycolic-poly (lactic acid composite induces mineralized barrier after direct capping of rat tooth pulp tissue

    Directory of Open Access Journals (Sweden)

    Alfonso Gala-Garcia

    2010-03-01

    Full Text Available The aim of this study was to observe the histopathological pulp response following direct pulp capping of mechanically exposed teeth in rats with a composite of beta-tricalcium phosphate-hydroxyapatite bioceramic (BC and poly (glycolic-poly (lactic acid (PLGA material or a calcium hydroxide [Ca(OH2] material, compared to BC alone and a negative control of water. Pulp of the maxillary molars was exposed, followed by capping with the experimental material. The pulpal tissue response was assessed post-operatively at 1, 7, 14 and 30 d, followed by histological analysis. The Ca(OH2 group exhibited severe acute inflammatory cell infiltration at day 14. However after 30 d, a new hard tissue with macro porous obliteration of the pulp chamber and a characteristic necrotic area had appeared. BC and Ca(OH2 capping were associated with moderate inflammation and dentinal bridge similar. Meanwhile, in the BC/PLGA composite group, there was moderate inflammatory infiltrate and formation of a dense and complete dentinal bridge. In conclusion, the BC/PLGA composite material showed a large zone of tertiary dentin, and effectively reorganized the dentin-pulp complex.

  15. Recovery of Nickel from Reformer Catalysts of Direct Reduction, Using the Pressurized Dissolving Method in Nitric Acid

    Directory of Open Access Journals (Sweden)

    B. Abrar

    2016-10-01

    Full Text Available In the process of direct reduction of iron pellet and production of sponge iron, NiO/Al2O3 act as a catalyst for the generation of carbon monoxide and hydrogen by vapor and natural gas. As an expensive material used in MIDREX method for steel units, this type of catalyst has major environmental problems after accumulation. The steel industry in Iran hopes to employ the MIDREX technique for the 80 percent of the 50 million tons of steel. Thus, the problem of spent catalysts will become a serious environmental challenge. Through the hydrometallurgy method, the present study investigates a possible solution to the problem of catalyst depot (due to heavy metals such as nickel via nickel recovery, which may increase the possibility of selling or re-using the precious and expensive metal. The present research studied the Nickel recovery from spent catalysts of NiO/Al2O¬3 used in reduction gas reliefs of the production of sponge iron unit. In this study, the parameters of temperature, concentration, time and Rpm were studied using pressurized dissolving method. 100% efficiency was achieved at 140 °C for 120 minutes, nitric acid concentration of 1.5 mm, Rpm of 600 and 40 s/l 40 grams per liter.

  16. Modulatory effects of the antioxidant ascorbic acid on the direct genotoxicity of doxorubicin in somatic cells of Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Edson José Fragiorge

    2007-03-01

    Full Text Available In this study two different crosses involving the wing cell markers mwh and flr³ (standard (ST cross and high bioactivation (HB cross, the latter being characterized by a high constitutive level of cytochrome P450 which leads to an increased sensitivity to a number of promutagens and procarcinogens were used to investigate the modulatory effects of ascorbic acid (AA combined with the antitumor agent doxorubicin (DXR in Drosophila melanogaster. We observed that the two different concentrations of AA (50 or 100 mM had no effect on spots frequencies, while DXR treatments (0.2 or 0.4 mM gave positive results for all types of spots, when compared to negative control. For marker-heterozygous (MH flies, a protective effect was observed with the lower concentration of AA (50 mM that was able to statistically decrease the frequency of spots induced by DXR (0.2 mM, while an enhanced frequency of spots induced by DXR was observed with the higher concentration of AA (100 mM, when compared to DXR treatment (p < 0.05. These results suggest that AA may interfere with free radicals generated by DXR and with other possible reactive metabolites. The efficiency of AA in protecting the somatic cells of D. melanogaster against mutation and recombination induced by DXR is dependent on the dose used and the protection is directly related to the activity of cytochrome P450 enzymes.

  17. Facile fabrication of robust silk nanofibril films via direct dissolution of silk in CaCl2-formic acid solution.

    Science.gov (United States)

    Zhang, Feng; You, Xinran; Dou, Hao; Liu, Zhi; Zuo, Baoqi; Zhang, Xueguang

    2015-02-11

    In this study, we report for the first time a novel silk fibroin (SF) nanofibrous films with robust mechanical properties that was fabricated by directly dissolving silk in CaCl2-formic acid solution. CaCl2-FA dissolved silk rapidly at room temperature, and more importantly, it disintegrated silk into nanofibrils instead of separate molecules. The morphology of nanofibrils crucially depended on CaCl2 concentrations, which resulted in different aggregation nanostructure in SF films. The SF film after drawing had maximum elastic modulus, ultimate tensile strength, and strain at break reaching 4 GPa, 106 MPa, and 29%, respectively, in dry state and 206 MPa, 28 MPa, and 188%, respectively, in wet state. Moreover, multiple yielding phenomena and substantially strain-hardening behavior was also observed in the stretched films, indicating the important role played by preparation method in regulating the mechanical properties of SF films. These exceptional and unique mechanical properties were suggested to be caused by preserving silk nanofibril during dissolution and stretching to align these nanofibrils. Furthermore, the SF films exhibit excellent biocompatibility, supporting marrow stromal cells adhesion and proliferation. The film preparation was facile, and the resulting SF films manifested enhanced mechanical properties, unique nanofibrous structures, and good biocompability.

  18. A fermentative approach towards optimizing directed biosynthesis of fumaric acid by Rhizopus oryzae 1526 utilizing apple industry waste biomass.

    Science.gov (United States)

    Das, Ratul Kumar; Brar, Satinder Kaur; Verma, Mausam

    2015-12-01

    The present research account deals with the bioproduction of fumaric acid (FA) from apple pomace ultrafiltration sludge (APUS) and apple pomace (AP) through fermentation. The filamentous fungus Rhizopus oryzae 1526 was used as a biocatalyst and its morphological impact on FA production was analysed in detail. For submerged fermentation, 40 g L(-1) of total solids concentration of APUS, pH 6.0, 30 °C, 200 rpm flask shaking speed and 72 h of incubation were found to be optimum for FA production (25.2 ± 1.0 g L(-1), 0.350 g (L(-1) h(-1))). Broth viscosity (cP), residual reducing sugar (g L(-1)) and ethanol (g L(-1)) produced as by-product, were also analysed. Plastic trays were used for solid state fermentation and at optimized level of moisture and incubation period, 52 ± 2.67 g FA per kg dry weight of AP was obtained. Changes in the total phenolic content (mg g(-1) dry weight of AP) were monitored at regular intervals. Utilization of APUS and AP for the directed synthesis of the high-value platform chemical FA by the fungal strain R. oryzae 1526 was an excellent display of fungal physiological and morphological control over a fermentative product.

  19. Influence of alkaline earth metals on molecular structure of 3-nitrobenzoic acid in comparison with alkali metals effect.

    Science.gov (United States)

    Samsonowicz, M; Regulska, E; Lewandowski, W

    2011-11-01

    The influence of beryllium, magnesium, calcium, strontium and barium cations on the electronic system of 3-nitrobenzoic acid was studied in comparison with studied earlier alkali metal ions. The vibrational FT-IR (in KBr and ATR techniques) and (1)H and (13)C NMR spectra were recorded for 3-nitrobenzoic acid and its salts. Characteristic shifts in IR and NMR spectra along 3-nitrobenzoates of divalent metal series Mg→Ba were compared with series of univalent metal Li→Cs salts. Good correlations between the wavenumbers of the vibrational bands in the IR spectra for 3-nitrobenzoates and ionic potential, electronegativity, inverse of atomic mass, atomic radius and ionization energy of metals were found for alkaline earth metals as well as for alkali metals. The density functional (DFT) hybrid method B3LYP with two basis sets: 6-311++G** and LANL2DZ were used to calculate optimized geometrical structures of studied compounds. The theoretical wavenumbers and intensities of IR spectra as well as chemical shifts in NMR spectra were obtained. Geometric aromaticity indices, atomic charges, dipole moments and energies were also calculated. The calculated parameters were compared to experimental characteristic of studied compounds.

  20. Identification of a novel HMW glutenin subunit and comparison of its amino acid sequence with those of homologous subunits

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Aegilops tauschii is the donor of the D genome of common wheat (Triticum aestivum). Genetic variation of HMW glutenin subunits encoded by the Glu-1Dt locus of Ae. tauschii has been found to be higher than that specified by the Glu-1D locus in common wheat. In the present note, we report the identification of a novel HMW glutenin subunit, Dy13t, from Ae. tauschii. The newly identified subunit possessed an electrophoretic mobility that was faster than that of the Dy12 subunit of common wheat. The complete ORF of encoding the Dy13t subunit contained 624 codons (excluding the stop codons). The amino acid sequence deduced from the Dy13t gene ORF was the shortest among those of the previously reported subunits derived by the D genome. A further comparison of Dy13t amino acid sequence with those of the subunits characterized from the A, B, D, R genomes of Triticeae showed that the smaller size of the Dy13t subunit was associated with a reduction in the size of its repetitive domain.

  1. Practical limitations of superresolution imaging due to conventional sample preparation revealed by a direct comparison of CLSM, SIM and dSTORM.

    Science.gov (United States)

    Bachmann, Michael; Fiederling, Felix; Bastmeyer, Martin

    2016-06-01

    We evaluate the suitability of conventional sample preparation and labelling methods for two superresolution techniques, structured illumination microscopy and direct stochastic optical reconstruction microscopy, by a comparison to established confocal laser scanning microscopy. We show that SIM is compatible with standard fixation procedures and immunofluorescence labelling protocols and improves resolution by a factor of two compared to confocal laser scanning microscopy. With direct stochastic optical reconstruction microscopy, fluorophores can theoretically be localized with much higher precision. However, in practice, with indirect immunofluorescence labelling density can be insufficient due to the bulky probes to reveal biological structures with high resolution. Fine structures like single actin fibres are in fact resolved with direct stochastic optical reconstruction microscopy when using small affinity probes, but require proper adjustment of the fixation protocol. Finally, by a direct comparison of immunofluorescent and genetic labelling with fluorescent proteins, we show that target morphology in direct stochastic optical reconstruction microscopy data sets can differ significantly depending on the labelling method and the molecular environment of the target.

  2. Comparison of Self-Etch Primers with Conventional Acid Etching System on Orthodontic Brackets

    Science.gov (United States)

    Zope, Amit; Zope-Khalekar, Yogita; Chitko, Shrikant S.; Kerudi, Veerendra V.; Patil, Harshal Ashok; Jaltare, Pratik; Dolas, Siddhesh G

    2016-01-01

    Introduction The self-etching primer system consists of etchant and primer dispersed in a single unit. The etching and priming are merged as a single step leading to fewer stages in bonding procedure and reduction in the number of steps that also reduces the chance of introduction of error, resulting in saving time for the clinician. It also results in smaller extent of enamel decalcification. Aim To compare the Shear Bond Strength (SBS) of orthodontic bracket bonded with Self-Etch Primers (SEP) and conventional acid etching system and to study the surface appearance of teeth after debonding; etching with conventional acid etch and self-etch priming, using stereomicroscope. Materials and Methods Five Groups (n=20) were created randomly from a total of 100 extracted premolars. In a control Group A, etching of enamel was done with 37% phosphoric acid and bonding of stainless steel brackets with Transbond XT (3M Unitek, Monrovia, California). Enamel conditioning in left over four Groups was done with self-etching primers and adhesives as follows: Group B-Transbond Plus (3M Unitek), Group C Xeno V+ (Dentsply), Group D-G-Bond (GC), Group E-One-Coat (Coltene). The Adhesive Remnant Index (ARI) score was also evaluated. Additionally, the surface roughness using profilometer were observed. Results Mean SBS of Group A was 18.26±7.5MPa, Group B was 10.93±4.02MPa, Group C was 6.88±2.91MPa while of Group D was 7.78±4.13MPa and Group E was 10.39±5.22MPa respectively. In conventional group ARI scores shows that over half of the adhesive was remaining on the surface of tooth (score 1 to 3). In self-etching primer groups ARI scores show that there was no or minor amount of adhesive remaining on the surface of tooth (score 4 and 5). SEP produces a lesser surface roughness on the enamel than conventional etching. However, statistical analysis shows significant correlation (p<0.001) of bond strength with surface roughness of enamel. Conclusion All groups might show clinically

  3. Directing Group in Decarboxylative Cross-Coupling: Copper-Catalyzed Site-Selective C-N Bond Formation from Nonactivated Aliphatic Carboxylic Acids.

    Science.gov (United States)

    Liu, Zhao-Jing; Lu, Xi; Wang, Guan; Li, Lei; Jiang, Wei-Tao; Wang, Yu-Dong; Xiao, Bin; Fu, Yao

    2016-08-03

    Copper-catalyzed directed decarboxylative amination of nonactivated aliphatic carboxylic acids is described. This intramolecular C-N bond formation reaction provides efficient access to the synthesis of pyrrolidine and piperidine derivatives as well as the modification of complex natural products. Moreover, this reaction presents excellent site-selectivity in the C-N bond formation step through the use of directing group. Our work can be considered as a big step toward controllable radical decarboxylative carbon-heteroatom cross-coupling.

  4. Comparison of Uric Acid Quantity with Different Food in Human Urine by Flow Injection Chemiluminescence Analysis

    Directory of Open Access Journals (Sweden)

    Jiajia Wang

    2013-01-01

    Full Text Available Based on the inhibitory effect of uric acid (UA on luminol-Co2+ chemiluminescence (CL system, a sensitive method for the determination of UA at nanomolar level by flow injection (FI CL was proposed. The proposed method was successfully applied to real-time monitoring of UA excretion in human 24 h urine with different food intake, showing that meats, vegetables, and porridge intake caused differential UA excretions of 879, 798, and 742 mg, respectively. It was also found that UA concentrations in urine under the three kinds of food intake simultaneously reached maximum at 2 h after meals with the values of 417, 318, and 288 μg mL−1, respectively. The UA concentration in human serum was also determined by this approach, and the possible mechanism of luminol-Co2+-UA CL reaction was discussed in detail.

  5. Comparison of geometrical isomerization of unsaturated fatty acids in selected commercially refined oils

    Directory of Open Access Journals (Sweden)

    Tasan, M.

    2011-09-01

    Full Text Available Four different commercially refined vegetable oils were analyzed by capillary gas-liquid chromatography for their trans fatty acid contents. The results obtained showed that the total trans FA contents in refined sunflower, corn, soybean, and hazelnut oils were 0.68 ± 0.41, 0.51 ± 0.24, 1.27 ± 0.57, and 0.26 ± 0.07% of total FA, respectively. The total trans FA comprised isomers of the C18:1, C18:2 and C18:3 FA. Meanwhile, five brands of the refined sunflower oil and two brands of hazelnut oil contained no measurable amounts of total trans C18:3 acids. The total trans C18:2 acid was the predominant trans FA found in the refined sunflower and corn oils, while trans polyunsaturated FAs for the refined soybean oils were found at high levels. However, total trans C18:1 acid was the major trans FA for refined hazelnut oils. The commercially refined vegetable oils with a relatively high total polyunsaturated FA contained considerable amounts of trans polyunsaturated isomers. This study indicates that it is necessary to optimize industrial deodorization, especially the time and temperature, for each different FA composition of oil used.

    Cuatro aceites vegetales refinados comerciales diferentes fueron analizados por cromatografía de gases para determinar el contenido en ácidos grasos trans. Los resultados obtenidos mostraron que el contenido total de los FA trans de aceites refinados de girasol, maíz, soja y avellana fueron 0.68 ± 0.41, 0.51 ± 0.24, 1.27 ± 0.57, y 0.26 ± 0.07% de FA totales, respetivamente. Los ácidos grasos totales trans comprenden a isómeros de FA C18:1, C18:2 y C18:3. Cinco marcas de aceites de girasol refinado y dos marcas de aceite de avellana contenían cantidades no medibles de ácidos trans C18:3 totales. Los ácidos C18:2 trans totales fueron los FA trans predominantes en el aceite de girasol y ma

  6. Comparison of aqueous ammonia and dilute acid pretreatment of bamboo fractions: Structure properties and enzymatic hydrolysis.

    Science.gov (United States)

    Xin, Donglin; Yang, Zhong; Liu, Feng; Xu, Xueru; Zhang, Junhua

    2015-01-01

    The effect of two pretreatments methods, aqueous ammonia (SAA) and dilute acid (DA), on the chemical compositions, cellulose crystallinity, morphologic change, and enzymatic hydrolysis of bamboo fractions (bamboo yellow, timber, green, and knot) was compared. Bamboo fractions with SAA pretreatment had better hydrolysability than those with DA pretreatment. High crystallinity index resulted in low hydrolysis yield in the conversion of SAA pretreated bamboo fractions, not DA pretreated fractions. The increase of cellulase loading had modestly positive effect in the hydrolysis of both SAA and DA pretreated bamboo fractions, while supplement of xylanase significantly increased the hydrolysis of the pretreated bamboo fractions, especially after SAA pretreatment. The results indicated that SAA pretreatment was more effective than DA pretreatment in conversion of bamboo fractions, and supplementation of xylanase was necessary in effective conversion of the SAA pretreated fractions into fermentable sugars.

  7. Comparison of the Acidity of Heteropolyacids Encapsulated in or Impregnated on SBA-15

    Directory of Open Access Journals (Sweden)

    Pinto Teresa

    2016-03-01

    Full Text Available Heteropolyacids (HPA immobilized onto SBA-15 silica were prepared by two different ways using either impregnation or encapsulation methodologies. Two Keggin-type HPA, H3PW12O40 and H4SiW12O40 were considered in this study. The resulting hybrid materials were fully characterized by N2 adsorption-desorption isotherms, XRD, FT-IR, Raman, diffuse reflectance UV-Vis spectroscopies and 31P MAS NMR. All characterization methods showed that at room temperature the catalysts contained well-dispersed and intact Keggin units throughout the solid. The catalytic activity of these solids was investigated in the isomerization of n-hexane. The impregnated and encapsulated phosphotungstic catalysts performed similarly in catalysis showing that the amount of active sites was nearly the same in both catalysts. On the contrary, the tungstosilicic encapsulated material was completely inactive while its impregnated counterpart was even more active than the phosphotungstic derived catalysts. The acidity of the solids was measured by various methods: microcalorimetry of ammonia adsorption, ammonia desorption followed by Temperature Programmed Desorption (TPD and DRIFT/GC-MS and pyridine adsorption followed by infrared spectroscopy. Only pyridine adsorption and ammonia desorption followed by DRIFT/GC-MS agreed with the catalytic data. Ammonia adsorption followed by microcalorimetry was not able to differentiate between the four catalysts while the TPD experiments led to unreliable results, as not only the evolved ammonia but also other molecules such as water were taken into account in the measurements. The behavior difference between the encapsulated silico- and phosphotungstic acids was explained by a more pronounced encapsulation in the case of silicon.

  8. Comparison of antioxidant activities between salvianolic acid B and Ginkgo biloba extract (Egb 761 )

    Institute of Scientific and Technical Information of China (English)

    Chang-suo LIU; Yong CHENG; Jin-feng HU; Wei ZHANG; Nai-hong CHEN; Jun-tian ZHANG

    2006-01-01

    Aim: To investigate and compare the antioxidant activities of salvianolic acid B (SalB) and Ginkgo biloba extract (EGb 761) in aqueous solution, rat microsomes and the cellular system. Methods: Superoxide anion (O-·2) was generated using xanthine/xanthine oxidase system and phenazine methosulate/NADH system, and the effects of SalB and EGb 761 on the generation of (O-·2) were achieved by spectrophotometric measurement of the product formed on reduction of nitro blue tetrazolium. Two different methods were used to assess the scavenging effects of the extracts on hydroxyl radical (·OH): HPLC method was used for quantitation of ·OH by oxy-radical trapping of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) to form DMPO-OH adducts in Fe2+-EDTA-H2O2 system. To confirm the HPLC data,·OH was also measured by spectrophotometry using a commercial detection kit. The anti-lipid peroxidation effects of the extracts in microsomes of rat brain, liver and kidney induced by ascorbate-NADPH were determined by thiobarbituric acid (TBA) method. The protective effects of the extracts on peroxide hydrogen (H2O2)-induced oxidative damage in SH-SY5Y cells were investigated by assessing cell viability assay, the level of lipid peroxidation, and the lactate dehydrogenase (LDH) release. Results: Both SalB and EGb 761 were able to scavenge O-·2 and ·OH, inhibit lipid peroxidation of microsomes, and protect SH-SY5Y cells against H2O2-induced oxidative damage. However, the concentration of SalB was far lower than that of EGb 761 when a similar effect was obtained. Conclusion: The antioxidant efficiency of SalB was greater than that of EGb 761. These results suggest that SalB, like EGb 761, has promising potential in treating oxidative damagederived neurodegenerative disorders.

  9. An atom-economic approach to carboxylic acids via Pd-catalyzed direct addition of formic acid to olefins with acetic anhydride as a co-catalyst.

    Science.gov (United States)

    Wang, Yang; Ren, Wenlong; Shi, Yian

    2015-08-21

    An effective Pd-catalyzed hydrocarboxylation of olefins using formic acid with acetic anhydride as a co-catalyst is described. A variety of carboxylic acids are obtained in good yields with high regioselectivities under mild reaction conditions without the use of toxic CO gas.

  10. Development and implementation of real-time nucleic acid amplification for the detection of enterovirus infections in comparison to rapid culture of various clinical specimens

    NARCIS (Netherlands)

    van Doornum, G J J; Schutten, Martin; Voermans, J; Guldemeester, G J J; Niesters, H G M

    2007-01-01

    Several real-time PCR and nucleic acid sequence-based amplification (NASBA) primer pairs and a modified real-time PCR primer pair for the detection of enteroviruses were compared. The modified real-time PCR primer pair was evaluated on clinical samples in comparison with cell culture using the Magna

  11. Comparison of Enzymatic Hydrolysis and Acid Hydrolysis of Sterol Glycosides from Foods Rich in Δ(7)-Sterols.

    Science.gov (United States)

    Münger, Linda H; Jutzi, Sabrina; Lampi, Anna-Maija; Nyström, Laura

    2015-08-01

    In this study, we present the difference in sterol composition of extracted steryl glycosides (SG) hydrolyzed by either enzymatic or acid hydrolysis. SG were analyzed from foods belonging to the plant families Cucurbitaceae (melon and pumpkin seeds) and Amaranthaceae (amaranth and beetroot), both of which are dominated by Δ(7)-sterols. Released sterols were quantified by gas chromatography with a flame ionization detector (GC-FID) and identified using gas chromatography/mass spectrometry (GC-MS). All Δ(7)-sterols identified (Δ(7)-stigmastenyl, spinasteryl, Δ(7)-campesteryl, Δ(7)-avenasteryl, poriferasta-7,25-dienyl and poriferasta-7,22,25-trienyl glucoside) underwent isomerization under acidic conditions and high temperature. Sterols with an ethylidene or methylidene side chain were found to form multiple artifacts. The artifact sterols coeluted with residues of incompletely isomerized Δ(7)-sterols, or Δ(5)-sterols if present, and could be identified as Δ(8(14))-sterols on the basis of relative retention time, and their MS spectra as trimethylsilyl (TMS) and acetate derivatives. For instance, SG from melon were composed of 66% Δ(7)-stigmastenol when enzymatic hydrolysis was performed, whereas with acid hydrolysis only 8% of Δ(7)-stigmastenol was determined. The artifact of Δ(7)-stigmastenol coeluted with residual non-isomerized spinasterol, demonstrating the high risk of misinterpretation of compositional data obtained after acid hydrolysis. Therefore, the accurate composition of SG from foods containing sterols with a double bond at C-7 can only be obtained by enzymatic hydrolysis or by direct analysis of the intact SG.

  12. Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids; Part I. Effects on growth performance, microbial populations and immune status

    Science.gov (United States)

    Pigs (n=88) weaned at 19 ± 2 d of age were used in a 14 d study to evaluate the effects of water-delivered direct-fed microbials (DFM) or organic acids on immune status, Salmonella infection and shedding, and intestinal microbial populations following a Salmonella Typhimurium challenge. Pigs were ch...

  13. Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids: Part II. Effects on intestinal histology and active nutrient transport

    Science.gov (United States)

    The objective of this study was to evaluate the effects of water-delivered direct-fed microbials (DFM) or organic acids on intestinal morphology and active nutrient absorption in weanling pigs following deliberate Salmonella infection. Pigs (n = 88) were weaned at 19 ± 2 d of age and assigned to one...

  14. The gastric acid secretagogue gastrin-releasing peptide and the inhibitor oxyntomodulin do not exert their effect directly on the parietal cell in the rat

    DEFF Research Database (Denmark)

    Poulsen, Steen Seier; Holst, J J

    1988-01-01

    Previous studies suggested that gastrin-releasing peptide (a neuropeptide found in rat oxyntic mucosa) and oxyntomodulin (a glucagon-containing peptide of mammalian gut) could directly affect the acid secretion of the parietal cells. We therefore studied their effect on gastric acid production in...... and histamine-stimulated parietal cells confirmed that the cells retained the normal morphology of intracellular organelles and that the cells responded to physiological stimulation by marked expansion of the intracellular canaliculi.......Previous studies suggested that gastrin-releasing peptide (a neuropeptide found in rat oxyntic mucosa) and oxyntomodulin (a glucagon-containing peptide of mammalian gut) could directly affect the acid secretion of the parietal cells. We therefore studied their effect on gastric acid production...... in vitro by measuring [14C]-aminopyrine accumulation, a reliable index of H+ generation, in isolated rat parietal cells. However, neither gastrin-releasing peptide nor oxyntomodulin influenced basal acid secretion or histamine-stimulated gastric acid secretion. Electron-microscopic studies of unstimulated...

  15. Comparison of skin effects of immediate treatment modalities in experimentally induced hydrofluoric acid skin burns.

    Science.gov (United States)

    Songur, Meltem K; Akdemir, Ovunc; Lineaweaver, William C; Cavusoglu, Turker; Ozsarac, Murat; Aktug, Huseyin; Songur, Ecmel; Tiftikcioglu, Yigit O

    2015-12-01

    Hydrofluoric acid (HF) burns cause immediate damage and painful long-term sequellae. Traditionally, chelating agents have been used as the initial treatment for such burns. We have introduced epidermal growth factor (EGF) into an HF model to compare EGF with Ca(2+) and Mg(2+) treatments; 40 Sprague Dawley rats were divided into five groups. Each rat suffered a 6 × 4 cm(2) burn induced by 40% HF. Group 1 had no treatment, group 2 had saline injected beneath the burn, group 3 received magnesium sulphate injections, group 4 received calcium gluconate and group 5 received EGF. Specimens were evaluated via planimetry and biopsy at intervals of 4, 8, 24 and 72 hours. Fluid losses were significantly less in the Mg(2+) and EGF groups. The EGF group had the smallest burn area, least oedema, least polymorphonuclear granulocyte (PMN) infiltration, most angiogenesis and highest fibroblast proliferation of any group (P < 0·005). EGF limited HF damage morphologically and histologically more effectively than Ca(2+) or Mg(2+). This finding indicates that HF treatment via growth factors may be an improvement over chelation therapy.

  16. Comparison of renal ultrasonography and dimercaptosuccinic acid renal scintigraphy in febrile urinary tract infection.

    Science.gov (United States)

    Ayazi, Parviz; Mahyar, Abolfazl; Noroozian, Elham; Esmailzadehha, Neda; Barikani, Ameneh

    2015-12-01

    Accurate and early diagnosis and appropriate treatment of patient with urinary tract infection (UTI) are essential for the prevention or restriction of permanent damage to the kidneys in children. The aim of this study was to compare renal ultrasonography (US) and dimercaptosuccinic acid (DMSA) renal scan in the diagnosis of patients with febrile urinary tract infection. This study involved the medical records of children with febrile urinary tract infection who were admitted to the children's hospital in Qazvin, Iran. Pyelonephritis was diagnosed on the basis of clinical symptoms, laboratory tests and abnormal DMSA renal scans. The criteria for abnormality of renal US were an increase or a decrease in diffuse or focal parenchymal echogenicity, loss of corticomedullary differentiation, kidney position irregularities, parenchymal reduction and increased kidney size. Of the 100 study patients, 23% had an abnormal US and 46% had an abnormal DMSA renal scan. Of the latter patients, 15 had concurrent abnormal US (P value ≤ 0.03, concordance rate: 18%). Renal US had a sensitivity of 32%, specificity of 85%, positive predictive value of 65% and negative predictive value of 60%. Of the 77 patients with normal US, 31 (40.2%) had an abnormal DMSA renal scan. Despite the benefits and accessibility of renal US, its value in the diagnosis of pyelonephritis is limited.

  17. Comparison of three-dimensional fluorescence analysis methods for predicting formation of trihalomethanes and haloacetic acids

    Institute of Scientific and Technical Information of China (English)

    Nicolás M.Peleato; Robert C.Andrews

    2015-01-01

    This work investigated the application of several fluorescence excitation-emission matrix analysis methods as natural organic matter (NOM) indicators for use in predicting the formation of trihalomethanes (THMs) and haloacetic acids (HAAs).Waters from four different sources (two rivers and two lakes) were subjected to jar testing followed by 24 hr disinfection by-product formation tests using chlorine.NOM was quantified using three common measures:dissolved organic carbon,ultraviolet absorbance at 254 nm,and specific ultraviolet absorbance as well as by principal component analysis,peak picking,and parallel factor analysis of fluorescence spectra.Based on multi-linear modeling of THMs and HAAs,principle component (PC) scores resulted in the lowest mean squared prediction error of cross-folded test sets (THMs:43.7 (μg/L)2,HAAs:233.3 (μg/L)2).Inclusion of principle components representative of protein-like material significantly decreased prediction error for both THMs and HAAs.Parallel factor analysis did not identify a protein-like component and resulted in prediction errors similar to traditional NOM surrogates as well as fluorescence peak picking.These results support the value of fluorescence excitation-emission matrix-principal component analysis as a suitable NOM indicator in predicting the formation of THMs and HAAs for the water sources studied.

  18. Comparison of Franz cells and microdialysis for assessing salicylic acid penetration through human skin.

    Science.gov (United States)

    Leveque, N; Makki, S; Hadgraft, J; Humbert, Ph

    2004-01-28

    The purpose of the present study was to compare Franz cells (FC) and microdialysis (MD) for monitoring the skin absorption of salicylic acid (SA). The influence of pH on SA flux was also assessed by these two techniques. Excised abdominal human skin was used in the experiments. SA was dissolved in phosphate buffer solutions of pH 2, 5 and 7 (2 mg/ml). SA concentrations in the receptor FC solutions and in MD samples were assessed by high performance liquid chromatography (HPLC). The results demonstrate that the flux of SA decreased with increased pH. The profiles permeation determined by Franz cells and microdialysis were similar. However, whatever the pH, the SA flux was higher with microdialysis than with Franz cells. The results showed that SA percutaneous permeation conformed to the pH partition hypothesis. The flux of SA was different when it was determined by the two techniques. The collect of SA, by these two techniques is different. The results of the two techniques are compared and discussed.

  19. Amino Acid Sequence and Structural Comparison of BACE1 and BACE2 Using Evolutionary Trace Method

    Directory of Open Access Journals (Sweden)

    Hoda Mirsafian

    2014-01-01

    Full Text Available Beta-amyloid precursor protein cleavage enzyme 1 (BACE1 and beta-amyloid precursor protein cleavage enzyme 2 (BACE2, members of aspartyl protease family, are close homologues and have high similarity in their protein crystal structures. However, their enzymatic properties differ leading to disparate clinical consequences. In order to identify the residues that are responsible for such differences, we used evolutionary trace (ET method to compare the amino acid conservation patterns of BACE1 and BACE2 in several mammalian species. We found that, in BACE1 and BACE2 structures, most of the ligand binding sites are conserved which indicate their enzymatic property of aspartyl protease family members. The other conserved residues are more or less randomly localized in other parts of the structures. Four group-specific residues were identified at the ligand binding site of BACE1 and BACE2. We postulated that these residues would be essential for selectivity of BACE1 and BACE2 biological functions and could be sites of interest for the design of selective inhibitors targeting either BACE1 or BACE2.

  20. CHANGES IN CORTICAL KYNURENIC ACID BI-DIRECTIONALLY MODULATE PREFRONTAL GLUTAMATE LEVELS AS ASSESSED BY MICRODIALYSIS AND RAPID ELECTROCHEMISTRY

    Science.gov (United States)

    Konradsson-Geuken, Ȧ.; Gash, C. R.; Wu, H.-Q.; Alexander, K. S.; Pellicciari, R.; Schwarcz, R.; Bruno, J.P.

    2010-01-01

    Using two in vivo methods, microdialysis and rapid in situ electrochemistry, this study examined the modulation of extracellular glutamate levels by endogenously produced kynurenic acid (KYNA) in the prefrontal cortex (PFC) of awake rats. Measured by microdialysis, intraperitoneal (i.p.) administration of KYNA's bioprecursor L-kynurenine dose-dependently elevated extracellular KYNA and reduced extracellular glutamate (nadir after 50 mg/kg kynurenine: 60% decrease from baseline values). This dose-dependent decrease in glutamate levels was also seen using a glutamate-sensitive microelectrode array (MEA) (31% decrease following 50 mg/kg kynurenine). The kynurenine-induced reduction in glutamate was blocked (microdialysis) or attenuated (MEA) by co-administration of galantamine (3 mg/kg, i.p.), a drug that competes with KYNA at an allosteric potentiating site of the α7 nicotinic acetylcholine receptor. In separate experiments, extracellular glutamate levels were measured by MEA following the local perfusion (45 min) of the PFC with kynurenine (2.5 μM) or the selective KYNA biosynthesis inhibitor S-ethylsulfonylbenzoylalanine (S-ESBA; 5 mM). In agreement with previous microdialysis studies, systemic kynurenine application produced a reversible reduction in glutamate (nadir: −29%), whereas perfusion with S-ESBA increased glutamate levels reversibly (maximum: +38%). Collectively, these results demonstrate that fluctuations in the biosynthesis of KYNA in the PFC bi-directionally modulate extracellular glutamate levels, and that qualitatively very similar data are obtained by microdialysis and MEA. Since KYNA levels are elevated in the PFC of individuals with schizophrenia, and since prefrontal glutamatergic and nicotinic transmission mediate cognitive flexibility, normalization of KYNA levels in the PFC may constitute an effective treatment strategy for alleviating cognitive deficits in schizophrenia. PMID:20600676

  1. In vitro release of theophylline from poly(lactic acid) sustained-release pellets prepared by direct compression.

    Science.gov (United States)

    Kader, A; Jalil, R

    1998-06-01

    Poly(L-lactic acid), (L-PLA) pellets containing theophylline as a model drug were prepared with increasing bovine serum albumin (BSA) load of 10, 20, 30, 40, or 50% by direct compression. The drug release from pellets was studied in phosphate buffered saline (PBS, pH 7.4) at 37 degrees C. The annealing effect on theophylline release from pellets was also studied at 20, 30, 60, and 80 degrees C. In all cases, release kinetics followed the Higuchian mechanism with an initial burst effect followed by sustained release of theophylline during the experimental period. Increasing BSA load resulted in a linear increase in Higuchian release rates presumably because of the hydrophilic nature of BSA. Furthermore, BSA did not interact chemically with the polymer matrix and was held physically by the dense polymer matrix. However, drug release decreased with an increase in annealing temperature. Release of theophylline was higher from PLA-BSA combination pellets compared to PLA pellets at temperatures below the glass transition temperature (Tg) of the polymer and lower for temperatures above Tg. The temperature effect on drug release may be attributed to both the reduction of core solubility in the bulk phase and the lowering of diffusibility of the polymeric membrane. No drug-polymer interactions or polymer degradation was observed within the experimental setup when studied by differential scanning calorimetry (DSC), infrared (FTIR) spectroscopy, and gravimetric methods. DSC studies of pellets showed no hints of microstructural changes (crystallinity) of the polymers. In our experiments, theophylline was released primarily by leaching through channels and not by polymer degradation. The release rate was dependent on BSA loading and annealing. It may be concluded that PLA pellets can be fabricated suitably using BSA and annealing to design sustained-release preparations of water-soluble drugs.

  2. Comparison of direct (X-ray diffraction and infrared spectrophotometry) and indirect (infrared spectrophotometry) methods for the analysis of alpha-quartz in airborne dusts.

    Science.gov (United States)

    Kauffer, E; Masson, A; Moulut, J C; Lecaque, T; Protois, J C

    2005-11-01

    In this study, the alpha-quartz contents measured by different analytical techniques (X-ray diffraction, direct method; and infrared spectrophotometry, direct and indirect methods) were compared. The analyses were carried out on filters sampled in an industrial setting by means of a Dorr-Oliver cyclone. To verify the methodology used, filters loaded with pure alpha-quartz were also analysed. By and large, the agreement between the two direct methods was close on average, but on the basis of a comparison of the individual results, considerable differences exist. In absolute value, the mean relative deviation between the two techniques was infrared) were on average 13% lower than the results obtained by the two direct methods with a more important difference (23%) for samples where calcite was identified by X-ray diffraction in comparison with those where it was not (8%). This underestimation, which was not owing to dust losses during preparation, is probably explained by the elimination of organic compounds during dust calcinations or by the transformation of mineral compounds. The indirect method introduces additional sample handling operations with more risk of material loss. When the quantity of calcined material was <0.4 mg, the weighing operations necessary to correct any losses of material resulted in considerable variability. In terms of overall uncertainty, it would be better in this case not to carry out correction and to employ an operating mode favouring the recovery of a maximum of material while accepting a bias of about 5-7%.

  3. Particle-laden Thin Film Flow: An Alternating Direction Implicit Scheme and Comparison between Theory, Numerical Simulations, and Experiments

    Science.gov (United States)

    2011-01-01

    While the plots look qualitatively similar, the more singular solutions for m = 1 have larger maxima...the more singular solutions for m = 1 have larger maxima. Figure 5.6: A comparison of scaled solutions. On the left, simulations of (5.7)-(5.8) with

  4. Identification of polymorphic tandem repeats by direct comparison of genome sequence from different bacterial strains : a web-based resource

    Directory of Open Access Journals (Sweden)

    Vergnaud Gilles

    2004-01-01

    Full Text Available Abstract Background Polymorphic tandem repeat typing is a new generic technology which has been proved to be very efficient for bacterial pathogens such as B. anthracis, M. tuberculosis, P. aeruginosa, L. pneumophila, Y. pestis. The previously developed tandem repeats database takes advantage of the release of genome sequence data for a growing number of bacteria to facilitate the identification of tandem repeats. The development of an assay then requires the evaluation of tandem repeat polymorphism on well-selected sets of isolates. In the case of major human pathogens, such as S. aureus, more than one strain is being sequenced, so that tandem repeats most likely to be polymorphic can now be selected in silico based on genome sequence comparison. Results In addition to the previously described general Tandem Repeats Database, we have developed a tool to automatically identify tandem repeats of a different length in the genome sequence of two (or more closely related bacterial strains. Genome comparisons are pre-computed. The results of the comparisons are parsed in a database, which can be conveniently queried over the internet according to criteria of practical value, including repeat unit length, predicted size difference, etc. Comparisons are available for 16 bacterial species, and the orthopox viruses, including the variola virus and three of its close neighbors. Conclusions We are presenting an internet-based resource to help develop and perform tandem repeats based bacterial strain typing. The tools accessible at http://minisatellites.u-psud.fr now comprise four parts. The Tandem Repeats Database enables the identification of tandem repeats across entire genomes. The Strain Comparison Page identifies tandem repeats differing between different genome sequences from the same species. The "Blast in the Tandem Repeats Database" facilitates the search for a known tandem repeat and the prediction of amplification product sizes. The "Bacterial

  5. A comparison between alkaline and decomplexing reagents to extract humic acids from low rank coals

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, D.; Cegarra, J.; Abad, M. [CSIC, Madrid (Spain). Centro de Edafologia y Biologia Aplicada del Segura

    1996-07-01

    Humic acids (HAs) were obtained from two low rank coals (lignite and leonardite) by using either alkali extractants (0.1 M NaOH, 0.1 M KOH or 0.25 M KOH) or solutions containing Na{sub 4}P{sub 2}O{sub 7} (0.1 M Na{sub 4}P{sub 2}O{sub 7} or 0.1 M NaOH/Na{sub 4}P{sub 2}O{sub 7}). In both coals, the greatest yields were obtained with 0.25 M KOH and the lowest with the 0.1 M alkalis, whereas the extractions based on Na{sub 4}P{sub 2}O{sub 7} yielded intermediate values and were more effective on the lignite. Chemical analysis showed that the leonardite HAs consisted of molecules that were less oxidized and had fewer functional groups than the HAs released form the lignite. Moreover, the HAs extracted by reagents containing Na{sub 4}P{sub 2}O{sub 7} exhibited more functional groups than those extracted with alkali, this effect being more apparent in lignite because of its greater cation exchange capacity. Gel permeation chromatography indicated that the leonardite HAs contained a greater proportion of higher molecular size compounds than the lignite HAs, and that both solutions containing Na{sub 4}P{sub 2}O{sub 7} released HAs with a greater proportion of smaller molecular compounds from the lignite than did the alkali extractants. 16 refs., 3 figs., 2 tabs.

  6. A Comparison of Foreign Direct Investments in Eurosian Countries to World Trend in the Period of 1995 - 2011

    Directory of Open Access Journals (Sweden)

    Hayri Tuzla

    2013-12-01

    Full Text Available The world which rapidly globalizes and where the boundaries diminish day by day, the foreign direct investments affect many diverse macroeconomic variables, specifically economic growth and unemployment. Most current studies support that there exists a strong causality relationship between foreign direct investments and economic growth.On the other hand, there exists a weaker positive causality relationship between economic growth and foreign direct investments. Moreover, it is an undeniable fact that the economic growth leads to a decline in unemployment. This study aims to compare the foreign direct investment trends of seven Eurasian countries (Azerbaijan, Kazakhstan, Kyrgyzstan, Tajikistan, Turkey, Turkmenistan and Uzbekistan in the period of 1995 and 2011. The results are compared to both the world foreign direct investment trend and the other Central Asian countries.

  7. Poly(DL-lactic acid) as a direct compression excipient in controlled release tablets - Part I. Compaction behaviour and release characteristics of poly(DL-lactic acid) matrix tablets

    NARCIS (Netherlands)

    Steendam, R; Lerk, CF

    1998-01-01

    High-molecular weight poly(DL-lactic acid) (PDLA, M-v 85000) was applied as a direct compression excipient in controlled release tablets. PDLA powders with good flowing properties were obtained by milling pre-cooled PDLA granules. Apparent yield pressure values ranged from 44 to 71 MPa for tablettin

  8. Pharmacokinetic study of a new oral buffered acetylsalicylic acid (ASA) formulation in comparison with plain ASA in healthy volunteers.

    Science.gov (United States)

    Viganò, G; Garagiola, U; Gaspari, F

    1991-01-01

    A single-blind, randomized, crossover pharmacokinetic study was carried out to investigate the bioavailability of a new oral buffered 325 mg acetylsalicylic acid (ASA) formulation (ASPIRINA 03) in comparison with a 325 mg plain tablet. Twelve healthy volunteers of both sexes, aged between 20 and 37 years, received buffered or plain ASA on two separate occasions with a wash-out interval of at least two weeks. ASA and salicylic acid (SA) plasma levels were determined by a chromatographic method. The results showed no difference between the area under concentration time curve (AUC0-infinity) ASA values of both formulations (p = 0.19), and buffered ASA relative bioavailability was 102.49% (= bioequivalence). A significant difference was found between the AUC0-30 min ASA values: 90.5 micrograms. min/ml with buffered and 67.7 micrograms. min/ml with the plain tablet (p less than 0.05). The buffered ASA time of maximum concentration was shorter (28 +/- 8 min) than the plain one (38 +/- 19 min, p less than 0.05). The plasma concentrations and pharmacokinetic parameters of SA were not significantly different after the administration of the two ASA formulations. The plain ASA tablet had a significantly lower (p less than 0.05) dissolution rate than buffered ASA tablet. Moreover, the buffered ASA tablet significantly (p less than 0.01) increased the pH by 0.5 units. In conclusion, the bioavailability of the new oral buffered ASA was equivalent to that of plain ASA, but the plasma concentration peak was reached in a shorter time.

  9. Quantitative analysis of caffeic and ferulic acids in oatmeal. Comparison of a conventional method with a stable isotope dilution assay.

    Science.gov (United States)

    Guth, H; Grosch, W

    1994-09-01

    [13C]Caffeic acid and [13C]ferulic acid were synthesized and then used as internal standards for the determination of these acids (free and esterified) in oatmeal. A comparative study indicated that 84% of the ferulic acid, but only 32% of the caffeic acid, which is more susceptible to oxidation than the former, could be found by a conventional analytical approach.

  10. Comparison of the frequency of functional SH3 domains with different limited sets of amino acids using mRNA display.

    Directory of Open Access Journals (Sweden)

    Junko Tanaka

    Full Text Available Although modern proteins consist of 20 different amino acids, it has been proposed that primordial proteins consisted of a small set of amino acids, and additional amino acids have gradually been recruited into the genetic code. This hypothesis has recently been supported by comparative genome sequence analysis, but no direct experimental approach has been reported. Here, we utilized a novel experimental approach to test a hypothesis that native-like globular proteins might be easily simplified by a set of putative primitive amino acids with retention of its structure and function than by a set of putative new amino acids. We performed in vitro selection of a functional SH3 domain as a model from partially randomized libraries with different sets of amino acids using mRNA display. Consequently, a library rich in putative primitive amino acids included a larger number of functional SH3 sequences than a library rich in putative new amino acids. Further, the functional SH3 sequences were enriched from the primitive library slightly earlier than from a randomized library with the full set of amino acids, while the function and structure of the selected SH3 proteins with the primitive alphabet were comparable with those from the 20 amino acid alphabet. Application of this approach to various combinations of codons in protein sequences may be useful not only for clarifying the precise order of the amino acid expansion in the early stages of protein evolution but also for efficiently creating novel functional proteins in the laboratory.

  11. Direct enantioseparation of underivatized aliphatic 3-hydroxyalkanoic acids with a quinine-based zwitterionic chiral stationary phase.

    Science.gov (United States)

    Ianni, Federica; Pataj, Zoltán; Gross, Harald; Sardella, Roccaldo; Natalini, Benedetto; Lindner, Wolfgang; Lämmerhofer, Michael

    2014-10-10

    While aliphatic 2-hydroxyalkanoic acids have been more or less successfully enantioseparated with various chiral stationary phases by HPLC and GC, analogous applications on underivatized aliphatic 3-hydroxyalkanoic acids are completely absent in the scientific literature. With the aim of closing this gap, the enantioseparation of 3-hydroxybutyric acid, 3-hydroxydecanoic acid and 3-hydroxymyristic acid has been performed with two ion-exchange type chiral stationary phases (CSPs): one containing the anion-exchange type tert-butyl carbamoyl quinine chiral selector motif (Chiralpak QN-AX), and the other carrying the new zwitterionic variant based on trans-(S,S)-2-aminocyclohexanesulfonic acid-derivatized quinine carbamate (Chiralpak ZWIX(+)) as the chiral selector and enantiodiscriminating element, respectively. The zwitterionic enantiorecognition material provided better results in terms of enantioselectivity and resolution compared to the anion-exchanger CSP at reduced retention times due to the intramolecular counterion effect imposed by the sulfonic acid moiety and its competition with the 3-hydroxyalkanoic acid analyte for ionic interaction at the quininium-anion exchanger site. It is thus recommended as the CSP of first choice for enantioseparations of the class of aliphatic 3-hydroxyalkanoic acids. With use of polar organic eluent composed of ACN/MeOH/AcOH - 95/5/0.05 (v/v/v), a good compromise in terms of analysis time and enantioresolution quality was accomplished. The major experimental variables have been investigated for optimization of the resolution and allowed to derive information on the enantiorecognition mechanism. Corresponding Chiralpak ZWIX(-), based on pseudo-enantiomeric selector derived from quinidine and trans-(R,R)-2-aminocyclohexanesulfonic acid with opposite configurations provided reversed enantiomer elution orders. It has further to be stressed that these separations can be obtained with mass spectrometry compatible mobile phases.

  12. Parallel direct numerical simulation of turbulent flows in rotor-stator cavities. Comparison with k-{epsilon} modeling; Simulation numerique directe parallele d`ecoulements turbulents en cavites rotor-stator comparaisons avec les modilisations k-{epsilon}

    Energy Technology Data Exchange (ETDEWEB)

    Jacques, R.; Le Quere, P.; Daube, O. [Centre National de la Recherche Scientifique (CNRS), 91 - Orsay (France)

    1997-12-31

    Turbulent flows between a fixed disc and a rotating disc are encountered in various applications like turbo-machineries or torque converters of automatic gear boxes. These flows are characterised by particular physical phenomena mainly due to the effects of rotation (Coriolis and inertia forces) and thus, classical k-{epsilon}-type modeling gives approximative results. The aim of this work is to study these flows using direct numerical simulation in order to provide precise information about the statistical turbulent quantities and to improve the k-{epsilon} modeling in the industrial MATHILDA code of the ONERA and used by SNECMA company (aerospace industry). The results presented are restricted to the comparison between results obtained with direct simulation and results obtained with the MATHILDA code in the same configuration. (J.S.) 8 refs.

  13. Comparison of neurotropic effects of L-glutamic acid and its new derivative β-phenylglutamic acid hydrochloride (RGPU-135, glutarone).

    Science.gov (United States)

    Tyurenkov, I N; Bagmetova, V V; Chernysheva, Yu V; Merkushenkova, O V

    2014-04-01

    In contrast to L-glutamic acid (200 mg/kg), β-phenylglutamic acid hydrochloride (26 mg/kg) produces no anticonvulsant effects during generalized convulsions induced by "maximum electric shock". However, β-phenylglutamic acid hydrochloride was more potent than L-glutamic acid in increasing survival rate, promoting recovery of spontaneous motor activity, and maintainance locomotor and exploratory activity in the open field test and cognitive functions in conditioned passive avoidance test, i.e. exhibited neuroprotective activity. This substance did not change the threshold of pain induced by electric stimulation of paws (up to vocalization) and thermal tail stimulation (tail-flick), whereas L-glutamic acid decreased this parameter. β-Phenylglutamic acid suppressed aggression in the test for provoked unmotivated aggression, while L-glutamic acid enhanced it. Due to these neurotropic effects, β-phenylglutamic acid hydrochloride can be used as the basis for the development of drugs with antidepressant, anxiolytic, and neuroprotective actions.

  14. A NEW ROUTE TO DIRECT CATALYTIC SYNTHESIS OF ACETIC ACID FROM METHANE BY A LOW-TEMPERATURE REACTION%甲烷低温催化直接合成乙酸的新途径

    Institute of Scientific and Technical Information of China (English)

    丁一慧; 黄伟; 晋萍; 谢克昌

    2001-01-01

    The selective conversion of methane to more useful target products such as acetic acid would be far more attractive. The classical utilization and recent research for methane conversion to acetic acid by both the indirect route involved multi-step process through syngas stage and the direct one avoided syngas production were reviewed in this paper. Technology comparison and results analysis of the indirect route with the direct one, and of homogeneous catalyst systems with heterogeneous ones employed in oxidative carbonylation or carboxylation of methane to synthesize acetic acid directly led to such a suggestion as follows. That is, an environmentally benign route to direct synthesis of acetic acid from inexpensive feedstocks methane and carbon dioxide, in particular, using solid, heterogeneous catalysts at low temperature has its remarkable significance in view of energy, environment and economy. The further research will enrich the theory and practice of green C1 chemistry and performance of thermodynamically unfavo-rable reactions.%对甲烷经合成气路线间接制乙酸的现状及在温和条件下直接转化制乙酸的研究进展作了述评.通过对间接与直接路线的比较,以及在直接路线中,甲烷低温氧化羰化和直接羧化制乙酸均相与非均相催化体系的分析,指出了CH4-CO2低温直接合成乙酸在工艺过程上的显著优势,尤其是采用非均相催化体系.该工艺为乙酸合成和CH4与CO2的绿色化学利用开辟了新途径,其研究将会丰富C1化学化工的理论与实践,并为实现热力学不利反应提供实验方法和理论依据.

  15. Direct Comparison of the Performance of a Bio-inspired Synthetic Nickel Catalyst and a [NiFe]-Hydrogenase, Both Covalently Attached to Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Macia, Patricia; Dutta, Arnab; Lubitz, Wolfgang; Shaw, Wendy J.; Rudiger, Olaf

    2015-10-12

    The active site of hydrogenases has been a source of inspiration for the development of molecular catalysts. However, direct comparisons between molecular catalysts and enzymes have not been possible because different techniques are used to evaluate both types of catalysts, minimizing our ability to determine how far we’ve come in mimicking the impressive enzymatic performance. Here we directly compare the catalytic properties of the [Ni(PCy2NGly2)2]2+ complex with the [NiFe]-hydrogenase from Desulfobivrio vulgaris Miyazaki F (DvMF) immobilized to a functionalized electrode under identical conditions. At pH=7, the enzyme has higher performance in both activity and overpotential, and is more stable, while at low pH, the molecular catalyst outperforms the enzyme in all respects. The Ni complex also has increased tolerance to CO. This is the first direct comparison of enzymes and molecular complexes, enabling a unique understanding of the benefits and detriments of both systems, and advancing our understanding of the utilization of these bioinspired complexes in fuel cells. AD and WJS acknowledge the Office of Science Early Career Research Program through the US Department of Energy (US DOE), Office of Science, Office of Basic Energy Sciences (BES), and Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for the US DOE.

  16. Delineating the core regulatory elements crucial for directed cell migration by examining folic-acid-mediated responses.

    Science.gov (United States)

    Srinivasan, Kamalakkannan; Wright, Gus A; Hames, Nicole; Housman, Max; Roberts, Alayna; Aufderheide, Karl J; Janetopoulos, Chris

    2013-01-01

    Dictyostelium discoideum shows chemotaxis towards folic acid (FA) throughout vegetative growth, and towards cAMP during development. We determined the spatiotemporal localization of cytoskeletal and signaling molecules and investigated the FA-mediated responses in a number of signaling mutants to further our understanding of the core regulatory elements that are crucial for cell migration. Proteins enriched in the pseudopods during chemotaxis also relocalize transiently to the plasma membrane during uniform FA stimulation. In contrast, proteins that are absent from the pseudopods during migration redistribute transiently from the PM to the cytosol when cells are globally stimulated with FA. These chemotactic responses to FA were also examined in cells lacking the GTPases Ras C and G. Although Ras and phosphoinositide 3-kinase activity were significantly decreased in Ras G and Ras C/G nulls, these mutants still migrated towards FA, indicating that other pathways must support FA-mediated chemotaxis. We also examined the spatial movements of PTEN in response to uniform FA and cAMP stimulation in phospholipase C (PLC) null cells. The lack of PLC strongly influences the localization of PTEN in response to FA, but not cAMP. In addition, we compared the gradient-sensing behavior of polarized cells migrating towards cAMP to that of unpolarized cells migrating towards FA. The majority of polarized cells make U-turns when the cAMP gradient is switched from the front of the cell to the rear. Conversely, unpolarized cells immediately extend pseudopods towards the new FA source. We also observed that plasma membrane phosphatidylinositol 3,4,5-trisphosphate [PtdIns(3,4,5)P3] levels oscillate in unpolarized cells treated with Latrunculin-A, whereas polarized cells had stable plasma membrane PtdIns(3,4,5)P3 responses toward the chemoattractant gradient source. Results were similar for cells that were starved for 4 hours, with a mixture of polarized and unpolarized cells responding

  17. Pt-Ni and Pt-M-Ni (M = Ru, Sn Anode Catalysts for Low-Temperature Acidic Direct Alcohol Fuel Cells: A Review

    Directory of Open Access Journals (Sweden)

    Ermete Antolini

    2017-01-01

    Full Text Available In view of a possible use as anode materials in acidic direct alcohol fuel cells, the electro-catalytic activity of Pt-Ni and Pt-M-Ni (M = Ru, Sn catalysts for methanol and ethanol oxidation has been widely investigated. An overview of literature data regarding the effect of the addition of Ni to Pt and Pt-M on the methanol and ethanol oxidation activity in acid environment of the resulting binary and ternary Ni-containing Pt-based catalysts is presented, highlighting the effect of alloyed and non-alloyed nickel on the catalytic activity of these materials.

  18. Production of L-lactic acid by direct fermentation of potato; Bareisho wo genryo to suru chokusetsu L-nyusan hakko

    Energy Technology Data Exchange (ETDEWEB)

    Yokota, Y.; Tanaka, S.; Yumoto, I.; Morita, M. [Hokkaido National Industrial Research Institute, Sapporo (Japan); Kusakabe, T. [SETEC Corp., Sapporo (Japan)

    1998-09-05

    L-lactic acid was produced by direct fermentation of potato using Lactobacillus amylophilus which has both the ability to saccharify starch and produce L-lactic acid. Potato was found to be a more suitable fermentation substrate compared to purified potato starch. It is estimated that protein and oligosacchalide which are contained in potato contribute as fermentation promoters. The utilization of squid entrails or scallop entrails as culture nutrients instead of polypeptone and yeast extract is extiemely successful. In particular, fermentation in squid entrails is strongly promoted, and is considered to come from enhancement of saccharification ability of Lactobacillus amylophilus. 4 refs., 4 figs., 2 tabs.

  19. Comparison of LUCIO®-direct ELISA with CEDIA immunoassay for 'zero tolerance' drug screening in urine as required by the German re-licensing guidelines.

    Science.gov (United States)

    Agius, Ronald; Nadulski, Thomas; Kahl, Hans-Gerhard; Dufaux, Bertin

    2013-06-01

    The performance of the previously validated LUCIO(®)-Direct-enzyme linked immunosorbent assay (direct ELISA) screening tests according to forensic guidelines is compared to that of cloned enzyme donor immunoassays (CEDIA) test for drugs of abuse in urine as defined in the new re-licensing German medical and psychological assessment (MPA) guidelines. The MPA screening cut-offs correspond to 10 ng/ml 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH), 50 ng/ml amphetamine and designer amphetamines, 25 ng/ml morphine, codeine and dihydrocodeine, 30 ng/ml benzoylecgonine, 50 ng/ml methadone metabolite, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) and metabolites of diazepam, oxazepam, bromazepam, alprazolam, flunitrazepam and lorazepam at 50 ng/ml. Average relative sensitivities and relative specificities were 99.7 % and 98.4 % for direct ELISA and 66 % and 91.4 % for CEDIA, respectively.

  20. Comparative researches on two direct transmethylation without prior extraction methods for fatty acids analysis in vegetal matrix with low fat content

    Directory of Open Access Journals (Sweden)

    Harmanescu Monica

    2012-01-01

    Full Text Available Abstract Background The aim of our work was to compare two methods, both based on direct transmethylation with different reagents, BF3/MeOH (boron trifluoride in methanol or HCl/MeOH (hydrochloride acid in methanol, in acid catalysis, without prior extraction, to find the fast, non-expensive but enough precise method for 9 principal fatty acids (lauric, myristic, palmitic, stearic, oleic, linoleic, linolenic, arahidic and behenic acids analysis in vegetal matrix with low fat content (forage from grassland, for nutrition and agrochemical studies. Results Comparatively, between the average values obtained for all analysed fatty acids by the two methods based on direct transmethylation without prior extraction no significantly difference was identified (p > 0.05. The results of fatty acids for the same forage sample were more closely to their average value, being more homogenous for BF3/MeOH than HCl/MeOH, because of the better accuracy and repeatability of this method. Method that uses BF3/MeOH reagent produces small amounts of interfering compounds than the method using HCl/MeOH reagent, results reflected by the better statistical parameters. Conclusion The fast and non-expensive BF3/methanol method was applied with good accuracy and sensitivity for the determination of free or combined fatty acids (saturated and unsaturated in forage matrix with low fat content from grassland. Also, the final extract obtained by this method, poorer in interfering compounds, is safer to protect the injector and column from contamination with heavy or non-volatile compounds formed by transmethylation reactions.