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Sample records for interface alanine scanning

  1. AlaScan: A Graphical User Interface for Alanine Scanning Free-Energy Calculations.

    Science.gov (United States)

    Ramadoss, Vijayaraj; Dehez, François; Chipot, Christophe

    2016-06-27

    Computation of the free-energy changes that underlie molecular recognition and association has gained significant importance due to its considerable potential in drug discovery. The massive increase of computational power in recent years substantiates the application of more accurate theoretical methods for the calculation of binding free energies. The impact of such advances is the application of parent approaches, like computational alanine scanning, to investigate in silico the effect of amino-acid replacement in protein-ligand and protein-protein complexes, or probe the thermostability of individual proteins. Because human effort represents a significant cost that precludes the routine use of this form of free-energy calculations, minimizing manual intervention constitutes a stringent prerequisite for any such systematic computation. With this objective in mind, we propose a new plug-in, referred to as AlaScan, developed within the popular visualization program VMD to automate the major steps in alanine-scanning calculations, employing free-energy perturbation as implemented in the widely used molecular dynamics code NAMD. The AlaScan plug-in can be utilized upstream, to prepare input files for selected alanine mutations. It can also be utilized downstream to perform the analysis of different alanine-scanning calculations and to report the free-energy estimates in a user-friendly graphical user interface, allowing favorable mutations to be identified at a glance. The plug-in also assists the end-user in assessing the reliability of the calculation through rapid visual inspection.

  2. Rapid mapping of protein functional epitopes by combinatorial alanine scanning

    OpenAIRE

    Weiss, GA; Watanabe, CK; Zhong, A; Goddard, A; Sidhu, SS

    2000-01-01

    A combinatorial alanine-scanning strategy was used to determine simultaneously the functional contributions of 19 side chains buried at the interface between human growth hormone and the extracellular domain of its receptor. A phage-displayed protein library was constructed in which the 19 side chains were preferentially allowed to vary only as the wild type or alanine. The library pool was subjected to binding selections to isolate functional clones, and DNA sequencing was used to determine ...

  3. New Parameters for Higher Accuracy in the Computation of Binding Free Energy Differences upon Alanine Scanning Mutagenesis on Protein-Protein Interfaces.

    Science.gov (United States)

    Simões, Inês C M; Costa, Inês P D; Coimbra, João T S; Ramos, Maria J; Fernandes, Pedro A

    2017-01-23

    Knowing how proteins make stable complexes enables the development of inhibitors to preclude protein-protein (P:P) binding. The identification of the specific interfacial residues that mostly contribute to protein binding, denominated as hot spots, is thus critical. Here, we refine an in silico alanine scanning mutagenesis protocol, based on a residue-dependent dielectric constant version of the Molecular Mechanics/Poisson-Boltzmann Surface Area method. We have used a large data set of structurally diverse P:P complexes to redefine the residue-dependent dielectric constants used in the determination of binding free energies. The accuracy of the method was validated through comparison with experimental data, considering the per-residue P:P binding free energy (ΔΔG binding ) differences upon alanine mutation. Different protocols were tested, i.e., a geometry optimization protocol and three molecular dynamics (MD) protocols: (1) one using explicit water molecules, (2) another with an implicit solvation model, and (3) a third where we have carried out an accelerated MD with explicit water molecules. Using a set of protein dielectric constants (within the range from 1 to 20) we showed that the dielectric constants of 7 for nonpolar and polar residues and 11 for charged residues (and histidine) provide optimal ΔΔG binding predictions. An overall mean unsigned error (MUE) of 1.4 kcal mol -1 relative to the experiment was achieved in 210 mutations only with geometry optimization, which was further reduced with MD simulations (MUE of 1.1 kcal mol -1 for the MD employing explicit solvent). This recalibrated method allows for a better computational identification of hot spots, avoiding expensive and time-consuming experiments or thermodynamic integration/ free energy perturbation/ uBAR calculations, and will hopefully help new drug discovery campaigns in their quest of searching spots of interest for binding small drug-like molecules at P:P interfaces.

  4. End-to-end tests using alanine dosimetry in scanned proton beams

    Science.gov (United States)

    Carlino, A.; Gouldstone, C.; Kragl, G.; Traneus, E.; Marrale, M.; Vatnitsky, S.; Stock, M.; Palmans, H.

    2018-03-01

    This paper describes end-to-end test procedures as the last fundamental step of medical commissioning before starting clinical operation of the MedAustron synchrotron-based pencil beam scanning (PBS) therapy facility with protons. One in-house homogeneous phantom and two anthropomorphic heterogeneous (head and pelvis) phantoms were used for end-to-end tests at MedAustron. The phantoms were equipped with alanine detectors, radiochromic films and ionization chambers. The correction for the ‘quenching’ effect of alanine pellets was implemented in the Monte Carlo platform of the evaluation version of RayStation TPS. During the end-to-end tests, the phantoms were transferred through the workflow like real patients to simulate the entire clinical workflow: immobilization, imaging, treatment planning and dose delivery. Different clinical scenarios of increasing complexity were simulated: delivery of a single beam, two oblique beams without and with range shifter. In addition to the dose comparison in the plastic phantoms the dose obtained from alanine pellet readings was compared with the dose determined with the Farmer ionization chamber in water. A consistent systematic deviation of about 2% was found between alanine dosimetry and the ionization chamber dosimetry in water and plastic materials. Acceptable agreement of planned and delivered doses was observed together with consistent and reproducible results of the end-to-end testing performed with different dosimetric techniques (alanine detectors, ionization chambers and EBT3 radiochromic films). The results confirmed the adequate implementation and integration of the new PBS technology at MedAustron. This work demonstrates that alanine pellets are suitable detectors for end-to-end tests in proton beam therapy and the developed procedures with customized anthropomorphic phantoms can be used to support implementation of PBS technology in clinical practice.

  5. Naturally Inspired Peptide Leads: Alanine Scanning Reveals an Actin-Targeting Thiazole Analogue of Bisebromoamide.

    Science.gov (United States)

    Johnston, Heather J; Boys, Sarah K; Makda, Ashraff; Carragher, Neil O; Hulme, Alison N

    2016-09-02

    Systematic alanine scanning of the linear peptide bisebromoamide (BBA), isolated from a marine cyanobacterium, was enabled by solid-phase peptide synthesis of thiazole analogues. The analogues have comparable cytotoxicity (nanomolar) to that of BBA, and cellular morphology assays indicated that they target the actin cytoskeleton. Pathway inhibition in human colon tumour (HCT116) cells was explored by reverse phase protein array (RPPA) analysis, which showed a dose-dependent response in IRS-1 expression. Alanine scanning reveals a structural dependence to the cytotoxicity, actin targeting and pathway inhibition, and allows a new readily synthesised lead to be proposed. © 2016 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  6. Active Sites of Spinoxin, a Potassium Channel Scorpion Toxin, Elucidated by Systematic Alanine Scanning.

    Science.gov (United States)

    Peigneur, Steve; Yamaguchi, Yoko; Kawano, Chihiro; Nose, Takeru; Nirthanan, Selvanayagam; Gopalakrishnakone, Ponnampalam; Tytgat, Jan; Sato, Kazuki

    2016-05-31

    Peptide toxins from scorpion venoms constitute the largest group of toxins that target the voltage-gated potassium channel (Kv). Spinoxin (SPX) isolated from the venom of scorpion Heterometrus spinifer is a 34-residue peptide neurotoxin cross-linked by four disulfide bridges. SPX is a potent inhibitor of Kv1.3 potassium channels (IC50 = 63 nM), which are considered to be valid molecular targets in the diagnostics and therapy of various autoimmune disorders and cancers. Here we synthesized 25 analogues of SPX and analyzed the role of each amino acid in SPX using alanine scanning to study its structure-function relationships. All synthetic analogues showed similar disulfide bond pairings and secondary structures as native SPX. Alanine replacements at Lys(23), Asn(26), and Lys(30) resulted in loss of activity against Kv1.3 potassium channels, whereas replacements at Arg(7), Met(14), Lys(27), and Tyr(32) also largely reduced inhibitory activity. These results suggest that the side chains of these amino acids in SPX play an important role in its interaction with Kv1.3 channels. In particular, Lys(23) appears to be a key residue that underpins Kv1.3 channel inhibition. Of these seven amino acid residues, four are basic amino acids, suggesting that the positive electrostatic potential on the surface of SPX is likely required for high affinity interaction with Kv1.3 channels. This study provides insight into the structure-function relationships of SPX with implications for the rational design of new lead compounds targeting potassium channels with high potency.

  7. Characterization of the functional epitope on the urokinase receptor. Complete alanine scanning mutagenesis supplemented by chemical cross-linking

    DEFF Research Database (Denmark)

    Gårdsvoll, Henrik; Gilquin, Bernard; Le Du, Marie Hélène

    2006-01-01

    a comprehensive alanine scanning mutagenesis of uPAR combined with low resolution distance constraints defined within the complex using chemical cross-linkers as molecular rulers. The kinetic rate constants for the interaction between pro-uPA and 244 purified uPAR mutants with single-site replacements were...

  8. Whole-protein alanine-scanning mutagenesis of allostery: A large percentage of a protein can contribute to mechanism.

    Science.gov (United States)

    Tang, Qingling; Fenton, Aron W

    2017-09-01

    Many studies of allosteric mechanisms use limited numbers of mutations to test whether residues play "key" roles. However, if a large percentage of the protein contributes to allosteric function, mutating any residue would have a high probability of modifying allostery. Thus, a predicted mechanism that is dependent on only a few residues could erroneously appear to be supported. We used whole-protein alanine-scanning mutagenesis to determine which amino acid sidechains of human liver pyruvate kinase (hL-PYK; approved symbol PKLR) contribute to regulation by fructose-1,6-bisphosphate (Fru-1,6-BP; activator) and alanine (inhibitor). Each nonalanine/nonglycine residue of hL-PYK was mutated to alanine to generate 431 mutant proteins. Allosteric functions in active proteins were quantified by following substrate affinity over a concentration range of effectors. Results show that different residues contribute to the two allosteric functions. Only a small fraction of mutated residues perturbed inhibition by alanine. In contrast, a large percentage of mutated residues influenced activation by Fru-1,6-BP; inhibition by alanine is not simply the reverse of activation by Fru-1,6-BP. Moreover, the results show that Fru-1,6-BP activation would be extremely difficult to elucidate using a limited number of mutations. Additionally, this large mutational data set will be useful to train and test computational algorithms aiming to predict allosteric mechanisms. © 2017 Wiley Periodicals, Inc.

  9. Partial alanine scan of mast cell degranulating peptide (MCD): importance of the histidine- and arginine residues.

    Science.gov (United States)

    Buku, Angeliki; Mendlowitz, Milton; Condie, Barry A; Price, Joseph A

    2004-06-01

    The influence of the two histidine and two arginine residues of mast cell degranulating peptide (MCD) in activity and binding was studied by replacing these amino acids in the MCD sequence with L-alanine. Their histamine releasing activity was determined on rat peritoneal mast cells. Their binding affinity to the FcepsilonRIalpha binding subunit of the human mast cell receptor protein, was carried out using fluorescence polarization. The histamine assay showed that replacement of His13 by Ala o ccurred without loss of activity compared with the activity of MCD. Alanine substitutions for Arg7 and His8 resulted in an approximately 40 fold increase, and for Arg16 in a 14-fold increase in histamine-releasing activity of MCD. The binding affinities of the analogs were tested by competitive displacement of bound fluorescent MCD peptide from the FcepsilonRIalpha binding protein of the mast cell receptor by the Ala analogs using fluorescence polarization. The analogs Ala8 (for His) and Ala16 (for Arg) showed the same binding affinities as MCD, whereas analog Ala7 (for Arg) and analog Ala13 (for His) showed slightly better binding affinity than the parent compound. This study showed that the introduction of alanine residues in these positions resulted in MCD agonists of diverse potency. These findings will be useful in further MCD structure-activity studies.

  10. Alanine-scanning mutagenesis of human signal transducer and activator of transcription 1 to estimate loss- or gain-of-function variants.

    Science.gov (United States)

    Kagawa, Reiko; Fujiki, Ryoji; Tsumura, Miyuki; Sakata, Sonoko; Nishimura, Shiho; Itan, Yuval; Kong, Xiao-Fei; Kato, Zenichiro; Ohnishi, Hidenori; Hirata, Osamu; Saito, Satoshi; Ikeda, Maiko; El Baghdadi, Jamila; Bousfiha, Aziz; Fujiwara, Kaori; Oleastro, Matias; Yancoski, Judith; Perez, Laura; Danielian, Silvia; Ailal, Fatima; Takada, Hidetoshi; Hara, Toshiro; Puel, Anne; Boisson-Dupuis, Stéphanie; Bustamante, Jacinta; Casanova, Jean-Laurent; Ohara, Osamu; Okada, Satoshi; Kobayashi, Masao

    2017-07-01

    Germline heterozygous mutations in human signal transducer and activator of transcription 1 (STAT1) can cause loss of function (LOF), as in patients with Mendelian susceptibility to mycobacterial diseases, or gain of function (GOF), as in patients with chronic mucocutaneous candidiasis. LOF and GOF mutations are equally rare and can affect the same domains of STAT1, especially the coiled-coil domain (CCD) and DNA-binding domain (DBD). Moreover, 6% of patients with chronic mucocutaneous candidiasis with a GOF STAT1 mutation have mycobacterial disease, obscuring the functional significance of the identified STAT1 mutations. Current computational approaches, such as combined annotation-dependent depletion, do not distinguish LOF and GOF variants. We estimated variations in the CCD/DBD of STAT1. We mutagenized 342 individual wild-type amino acids in the CCD/DBD (45.6% of full-length STAT1) to alanine and tested the mutants for STAT1 transcriptional activity. Of these 342 mutants, 201 were neutral, 30 were LOF, and 111 were GOF mutations in a luciferase assay. This assay system correctly estimated all previously reported LOF mutations (100%) and slightly fewer GOF mutations (78.1%) in the CCD/DBD of STAT1. We found that GOF alanine mutants occurred at the interface of the antiparallel STAT1 dimer, suggesting that they destabilize this dimer. This assay also precisely predicted the effect of 2 hypomorphic and dominant negative mutations, E157K and G250E, in the CCD of STAT1 that we found in 2 unrelated patients with Mendelian susceptibility to mycobacterial diseases. The systematic alanine-scanning assay is a useful tool to estimate the GOF or LOF status and the effect of heterozygous missense mutations in STAT1 identified in patients with severe infectious diseases, including mycobacterial and fungal diseases. Copyright © 2016 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

  11. Characterizing the Hot Spots Involved in RON-MSPβ Complex Formation Using In Silico Alanine Scanning Mutagenesis and Molecular Dynamics Simulation

    Directory of Open Access Journals (Sweden)

    Omid Zarei

    2017-04-01

    Full Text Available Purpose: Implication of protein-protein interactions (PPIs in development of many diseases such as cancer makes them attractive for therapeutic intervention and rational drug design. RON (Recepteur d’Origine Nantais tyrosine kinase receptor has gained considerable attention as promising target in cancer therapy. The activation of RON via its ligand, macrophage stimulation protein (MSP is the most common mechanism of activation for this receptor. The aim of the current study was to perform in silico alanine scanning mutagenesis and to calculate binding energy for prediction of hot spots in protein-protein interface between RON and MSPβ chain (MSPβ. Methods: In this work the residues at the interface of RON-MSPβ complex were mutated to alanine and then molecular dynamics simulation was used to calculate binding free energy. Results: The results revealed that Gln193, Arg220, Glu287, Pro288, Glu289, and His424 residues from RON and Arg521, His528, Ser565, Glu658, and Arg683 from MSPβ may play important roles in protein-protein interaction between RON and MSP. Conclusion: Identification of these RON hot spots is important in designing anti-RON drugs when the aim is to disrupt RON-MSP interaction. In the same way, the acquired information regarding the critical amino acids of MSPβ can be used in the process of rational drug design for developing MSP antagonizing agents, the development of novel MSP mimicking peptides where inhibition of RON activation is required, and the design of experimental site directed mutagenesis studies.

  12. Alanine scanning of the rabies virus glycoprotein antigenic site III using recombinant rabies virus: implication for post-exposure treatment.

    Science.gov (United States)

    Papaneri, Amy B; Wirblich, Christoph; Marissen, Wilfred E; Schnell, Matthias J

    2013-12-02

    The safety and availability of the human polyclonal sera that is currently utilized for post-exposure treatment (PET) of rabies virus (RABV) infection remain a concern. Recombinant monoclonal antibodies have been postulated as suitable alternatives by WHO. To this extent, CL184, the RABV human antibody combination comprising monoclonal antibodies (mAbs) CR57 and CR4098, has been developed and has delivered promising clinical data to support its use for RABV PET. For this fully human IgG1 cocktail, mAbs CR57 and CR4098 are produced in the PER.C6 human cell line and combined in equal amounts in the final product. During preclinical evaluation, CR57 was shown to bind to antigenic site I whereas CR4098 neutralization was influenced by a mutation of position 336 (N336) located within antigenic site III. Here, alanine scanning was used to analyze the influence of mutations within the potential binding site for CR4098, antigenic site III, in order to evaluate the possibility of mutated rabies viruses escaping neutralization. For this approach, twenty flanking amino acids (10 upstream and 10 downstream) of the RABV glycoprotein (G) asparagine (N336) were exchanged to alanine (or serine, if already alanine) by site-directed mutagenesis. Analysis of G expression revealed four of the twenty mutant Gs to be non-functional, as shown by their lack of cell surface expression, which is a requirement for the production of infectious RABV. Therefore, these mutants were excluded from further study. The remaining sixteen mutants were introduced in an infectious clone of RABV, and recombinant RABVs (rRABVs) were recovered and utilized for in vitro neutralization assays. All of the viruses were effectively neutralized by CR4098 as well as by CR57, indicating that single amino acid exchanges in this region does not affect the broad neutralizing capability of the CL184 mAb combination. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Scanning control and data acquisition interface for a spectroscopy diagnostic

    International Nuclear Information System (INIS)

    Lopez-Callejas, R.; Galindo, S.; Benitez-Read, J.S.; Pacheco-Sotelo, J.; Longoria-Gandara, L.C.; Valencia-Alvarado, R.

    2001-01-01

    This work presents the design of a PC supported interface unit that improves the operation of a mechanically driven Czerny-Turner monochromator to the point of meeting the conditions required to be useful in wavelength separation and spectrum analysis for breakdown and conditioning discharges in plasma physics diagnostics. The PC supported interface verifies and sets the position and scan range of the instrument scanning drive. The interface consists of a microcontroller and its associated circuitry. The microcontroller is also used as a data acquisition and data manipulation element. An example of obtained spectra illustrating the instrument greatly improved performance is presented

  14. Tissue interfaces dosimetry in small field radiotherapy with alanine/EPR mini dosimeters and Monte Carlo-Penelope simulation

    Energy Technology Data Exchange (ETDEWEB)

    Vega R, J. L.; Nicolucci, P.; Baffa, O. [Universidade de Sao Paulo, FFCLRP, Departamento de Fisica, Av. Bandeirantes 3900, Bairro Monte Alegre, 14040-901 Ribeirao Preto, Sao Paulo (Brazil); Chen, F. [Universidade Federale do ABC, CCNH, Rua Santa Adelia 166, Bangu, 09210-170 Santo Andre, Sao Paulo (Brazil); Apaza V, D. G., E-mail: josevegaramirez@yahoo.es [Universidad Nacional de San Agustin de Arequipa, Departamento de Fisica, Arequipa (Peru)

    2014-08-15

    The dosimetry system based on alanine mini dosimeters plus K-Band EPR spectrometer was tested in the tissue-interface dosimetry through the percentage depth-dose (Pdd) determination for 3 x 3 cm{sup 2} and 1 x 1 cm{sup 2} radiation fields sizes. The alanine mini dosimeters were produced by mechanical pressure from a mixture of 95% L-alanine and 5% polyvinyl alcohol (Pva) acting as binder. Nominal dimensions of these mini dosimeters were 1 mm diameter and 3 mm length as well as 3 - 4 mg mass. The EPR spectra of the mini dosimeters were registered using a K-Band (24 GHz) EPR spectrometer. The mini dosimeters were placed in a nonhomogeneous phantom and irradiated with 20 Gy in a 6 MV PRIMUS Siemens linear accelerator, with a source-to-surface distance of 100 cm using the small fields previously mentioned. The cylindrical non-homogeneous phantom was comprised of several disk-shaped plates of different materials in the sequence acrylic-bone cork-bone-acrylic, with dimensions 15 cm diameter and 1 cm thick. The plates were placed in descending order, starting from top with four acrylic plates followed by two bone plates plus eight cork plates plus two bone plates and finally, four acrylic plates (4-2-8-2-4). Pdd curves from the treatment planning system and from Monte Carlo simulation with Penelope code were determined. Mini dosimeters Pdd results show good agreement with Penelope, better than 95% for the cork homogeneous region and 97.7% in the bone heterogeneous region. In the first interface region, between acrylic and bone, it can see a dose increment of 0.6% for mini dosimeters compared to Penelope. At the second interface, between bone and cork, there is 9.1% of dose increment for mini dosimeter relative to Penelope. For the third (cork-bone) and fourth (bone-acrylic) interfaces, the dose increment for mini dosimeters compared to Penelope was 4.1% both. (Author)

  15. Tissue interfaces dosimetry in small field radiotherapy with alanine/EPR mini dosimeters and Monte Carlo-Penelope simulation

    International Nuclear Information System (INIS)

    Vega R, J. L.; Nicolucci, P.; Baffa, O.; Chen, F.; Apaza V, D. G.

    2014-08-01

    The dosimetry system based on alanine mini dosimeters plus K-Band EPR spectrometer was tested in the tissue-interface dosimetry through the percentage depth-dose (Pdd) determination for 3 x 3 cm 2 and 1 x 1 cm 2 radiation fields sizes. The alanine mini dosimeters were produced by mechanical pressure from a mixture of 95% L-alanine and 5% polyvinyl alcohol (Pva) acting as binder. Nominal dimensions of these mini dosimeters were 1 mm diameter and 3 mm length as well as 3 - 4 mg mass. The EPR spectra of the mini dosimeters were registered using a K-Band (24 GHz) EPR spectrometer. The mini dosimeters were placed in a nonhomogeneous phantom and irradiated with 20 Gy in a 6 MV PRIMUS Siemens linear accelerator, with a source-to-surface distance of 100 cm using the small fields previously mentioned. The cylindrical non-homogeneous phantom was comprised of several disk-shaped plates of different materials in the sequence acrylic-bone cork-bone-acrylic, with dimensions 15 cm diameter and 1 cm thick. The plates were placed in descending order, starting from top with four acrylic plates followed by two bone plates plus eight cork plates plus two bone plates and finally, four acrylic plates (4-2-8-2-4). Pdd curves from the treatment planning system and from Monte Carlo simulation with Penelope code were determined. Mini dosimeters Pdd results show good agreement with Penelope, better than 95% for the cork homogeneous region and 97.7% in the bone heterogeneous region. In the first interface region, between acrylic and bone, it can see a dose increment of 0.6% for mini dosimeters compared to Penelope. At the second interface, between bone and cork, there is 9.1% of dose increment for mini dosimeter relative to Penelope. For the third (cork-bone) and fourth (bone-acrylic) interfaces, the dose increment for mini dosimeters compared to Penelope was 4.1% both. (Author)

  16. Alanine scan of the peptide antibiotic feglymycin: assessment of amino acid side chains contributing to antimicrobial activity.

    Science.gov (United States)

    Hänchen, Anne; Rausch, Saskia; Landmann, Benjamin; Toti, Luigi; Nusser, Antje; Süssmuth, Roderich D

    2013-03-18

    The antibiotic feglymycin is a linear 13-mer peptide synthesized by the bacterium Streptomyces sp. DSM 11171. It mainly consists of the nonproteinogenic amino acids 4-hydroxyphenylglycine and 3,5-dihydroxyphenylglycine. An alanine scan of feglymycin was performed by solution-phase peptide synthesis in order to assess the significance of individual amino acid side chains for biological activity. Hence, 13 peptides were synthesized from di- and tripeptide building blocks, and subsequently tested for antibacterial activity against Staphylococcus aureus strains. Furthermore we tested the inhibition of peptidoglycan biosynthesis enzymes MurA and MurC, which are inhibited by feglymycin. Whereas the antibacterial activity is significantly based on the three amino acids D-Hpg1, L-Hpg5, and L-Phe12, the inhibitory activity against MurA and MurC depends mainly on L-Asp13. The difference in the position dependence for antibacterial activity and enzyme inhibition suggests multiple molecular targets in the modes of action of feglymycin. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Cyclic peptide inhibitors of lysine-specific demethylase 1 with improved potency identified by alanine scanning mutagenesis.

    Science.gov (United States)

    Kumarasinghe, Isuru R; Woster, Patrick M

    2018-03-25

    Lysine-specific demethylase 1 (LSD1) is a chromatin-remodeling enzyme that plays an important role in cancer. Over-expression of LSD1 decreases methylation at histone 3 lysine 4, and aberrantly silences tumor suppressor genes. Inhibitors of LSD1 have been designed as chemical probes and potential antitumor agents. We recently reported the cyclic peptide 9, which potently and reversibly inhibits LSD1 (IC 50 2.1 μM; K i 385 nM). Systematic alanine mutagenesis of 9 revealed residues that are critical for LSD1 inhibition, and these mutated peptides were evaluated as LSD1 inhibitors. Alanine substitution at positions 2, 3, 4, 6 and 11-17 preserved inhibition, while substitution of alanine at positions 8 and 9 resulted in complete loss of activity. Cyclic mutant peptides 11 and 16 produced the greatest LSD1 inhibition, and 11, 16, 27 and 28 increased global H3K4me2 in K562 cells. In addition, 16, 27 and 28 promoted significant increases in H3K4me2 levels at the promoter sites of the genes IGFBP2 and FEZ1. Data from these LSD1 inhibitors will aid in the design of peptidomimetics with improved stability and pharmacokinetics. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  18. Identification of the roles of individual amino acid residues of the helix E of the major antenna of photosystem II (LHCII) by alanine scanning mutagenesis.

    Science.gov (United States)

    Liu, Cheng; Rao, Yan; Zhang, Lei; Yang, Chunhong

    2014-10-01

    The functions of the helix E (W97-F105), an amphiphilic lumenal 310 helix of the major antenna of photosystem II (LHCII), are still unidentified. To elucidate the roles of individual amino acid residue of the helix E, alanine scanning mutagenesis has been performed to mutate every residue of this domain to alanine. The influence of every alanine substitution on the structure and function of LHCII has been investigated biochemically and spectroscopically. The results show that all mutations have little impact on the pigment binding and configuration. However, many mutants presented decreased thermo- or photo-stability compared with the wild type, highlighting the significance of this helix to the stability of LHCII. The most critical residue for stability is W97. The mutant W97A yielded very fragile trimeric pigment protein complexes. The structural analysis revealed that the hydrogen bonding and aromatic interactions between W97, F195, F194 and a water molecule contributed greatly to the stability of LHCII. Moreover, Q103A and F105A have been identified to be able to reinforce the tendency of aggregation in vitro. The structural analysis suggested that the enhancement in aggregation formation for Q103A and F105A might be attributed to the changing hydrophobicity of the region. © The Authors 2014. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  19. Alanine dosimetry for clinical applications. Proceedings

    International Nuclear Information System (INIS)

    Anton, M.

    2006-05-01

    The following topics are dealt with: Therapy level alanine dosimetry at the UK Nationational Physical Laboratory, alanine as a precision validation tool for reference dosimetry, composition of alanine pellet dosimeters, the angular dependence of the alanine ESR spectrum, the CIAE alanine dosimeter for radiotherapy level, a correction for temporal evolution effects in alanine dosimetry, next-generation services foe e-traceability to ionization radiation national standards, establishing e-traceability to HIST high-dose measurement standards, alanine dosimetry of dose delivery from clinical accelerators, the e-scan alanine dosimeter reader, alanine dosimetry at ISS, verification of the integral delivered dose for IMRT treatment in the head and neck region with ESR/alanine dosimetry, alanine dosimetry in helical tomotherapy beams, ESR dosimetry research and development at the University of Palermo, lithium formate as a low-dose EPR radiation dosimeter, sensitivity enhancement of alanine/EPR dosimetry. (HSI)

  20. Improved scFv Anti-HIV-1 p17 Binding Affinity Guided from the Theoretical Calculation of Pairwise Decomposition Energies and Computational Alanine Scanning

    Directory of Open Access Journals (Sweden)

    Panthip Tue-ngeun

    2013-01-01

    Full Text Available Computational approaches have been used to evaluate and define important residues for protein-protein interactions, especially antigen-antibody complexes. In our previous study, pairwise decomposition of residue interaction energies of single chain Fv with HIV-1 p17 epitope variants has indicated the key specific residues in the complementary determining regions (CDRs of scFv anti-p17. In this present investigation in order to determine whether a specific side chain group of residue in CDRs plays an important role in bioactivity, computational alanine scanning has been applied. Molecular dynamics simulations were done with several complexes of original scFv anti-p17 and scFv anti-p17mutants with HIV-1 p17 epitope variants with a production run up to 10 ns. With the combination of pairwise decomposition residue interaction and alanine scanning calculations, the point mutation has been initially selected at the position MET100 to improve the residue binding affinity. The calculated docking interaction energy between a single mutation from methionine to either arginine or glycine has shown the improved binding affinity, contributed from the electrostatic interaction with the negative favorably interaction energy, compared to the wild type. Theoretical calculations agreed well with the results from the peptide ELISA results.

  1. Dosimetric comparison on tissue interfaces with TLD dosimeters, L-alanine, EDR2 films and Penelope simulation for a Co-60 source and linear accelerator in radiotherapy

    International Nuclear Information System (INIS)

    Vega R, J. L.; Cayllahua, F.; Apaza, D. G.; Javier, H.

    2015-10-01

    Percentage depth dose curves were obtained with TLD-100 dosimeters, EDR2 films and Penelope simulation at the interfaces in an inhomogeneous mannequin, composed by equivalent materials to the human body built for this study, consisting of cylindrical plates of solid water-bone-lung-bone-solid water of 15 cm in diameter and 1 cm in height; plates were placed in descending way (4-2-8-2-4). Irradiated with Co-60 source (Theratron Equinox-100) for small radiation fields 3 x 3 cm 2 and 1 x 1 cm 2 at a surface source distance of 100 cm from mannequin. The TLD-100 dosimeters were placed in the center of each plate of mannequin irradiated at 10 Gy. The results were compared between these measurement techniques, giving good agreement in interfaces better than 97%. This study was compared with the same characteristics of another study realized with other equivalent materials to human body not homogeneous acrylic-bone-cork-bone-acrylic. The percentage depth dose curves were obtained with mini-dosimeters L-alanine of 1 mm in diameter and 3 mm in height and 3.5 to 4.0 mg of mass with spectrometer band K (EPR). The mini-dosimeters were irradiated with a lineal accelerator PRIMUS Siemens 6 MV. The results of percentage depth dose of L-alanine mini-dosimeters show a good agreement with the percentage depth dose curves of Penelope code, better than 97.7% in interfaces of tissues. (Author)

  2. Alanine Scanning Mutagenesis Identifies an Asparagine–Arginine–Lysine Triad Essential to Assembly of the Shell of the Pdu Microcompartment

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Sharmistha; Cheng, Shouqiang; Sung, Yea Won; McNamara, Dan E.; Sawaya, Michael R.; Yeates, Todd O.; Bobik, Thomas A.

    2014-06-01

    Bacterial microcompartments (MCPs) are the simplest organelles known. They function to enhance metabolic pathways by confining several related enzymes inside an all-protein envelope called the shell. In this study, we investigated the factors that govern MCP assembly by performing scanning mutagenesis on the surface residues of PduA, a major shell protein of the MCP used for 1,2-propanediol degradation. Biochemical, genetic, and structural analysis of 20 mutants allowed us to determine that PduA K26, N29, and R79 are crucial residues that stabilize the shell of the 1,2-propanediol MCP. In addition, we identify two PduA mutants (K37A and K55A) that impair MCP function most likely by altering the permeability of its protein shell. These are the first studies to examine the phenotypic effects of shell protein structural mutations in an MCP system. The findings reported here may be applicable to engineering protein containers with improved stability for biotechnology applications.

  3. Investigation of the structural requirements of K-Ras(G12D) selective inhibitory peptide KRpep-2d using alanine scans and cysteine bridging.

    Science.gov (United States)

    Niida, Ayumu; Sasaki, Shigekazu; Yonemori, Kazuko; Sameshima, Tomoya; Yaguchi, Masahiro; Asami, Taiji; Sakamoto, Kotaro; Kamaura, Masahiro

    2017-06-15

    A structure-activity relationship study of a K-Ras(G12D) selective inhibitory cyclic peptide, KRpep-2d was performed. Alanine scanning of KRpep-2d focusing on the cyclic moiety showed that Leu 7 , Ile 9 , and Asp 12 are the key elements for K-Ras(G12D) selective inhibition of KRpep-2d. The cysteine bridging was also examined to identify the stable analog of KRpep-2d under reductive conditions. As a result, the KRpep-2d analog (12) including mono-methylene bridging showed potent K-Ras(G12D) selective inhibition in both the presence and the absence of dithiothreitol. This means that mono-methylene bridging is an effective strategy to obtain a reduction-resistance analog of parent disulfide cyclic peptides. Peptide 12 inhibited proliferation of K-Ras(G12D)-driven cancer cells significantly. These results gave valuable information for further optimization of KRpep-2d to provide novel anti-cancer drug candidates targeting the K-Ras(G12D) mutant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Molecular Determinants Underlying Binding Specificities of the ABL Kinase Inhibitors: Combining Alanine Scanning of Binding Hot Spots with Network Analysis of Residue Interactions and Coevolution.

    Directory of Open Access Journals (Sweden)

    Amanda Tse

    Full Text Available Quantifying binding specificity and drug resistance of protein kinase inhibitors is of fundamental importance and remains highly challenging due to complex interplay of structural and thermodynamic factors. In this work, molecular simulations and computational alanine scanning are combined with the network-based approaches to characterize molecular determinants underlying binding specificities of the ABL kinase inhibitors. The proposed theoretical framework unveiled a relationship between ligand binding and inhibitor-mediated changes in the residue interaction networks. By using topological parameters, we have described the organization of the residue interaction networks and networks of coevolving residues in the ABL kinase structures. This analysis has shown that functionally critical regulatory residues can simultaneously embody strong coevolutionary signal and high network centrality with a propensity to be energetic hot spots for drug binding. We have found that selective (Nilotinib and promiscuous (Bosutinib, Dasatinib kinase inhibitors can use their energetic hot spots to differentially modulate stability of the residue interaction networks, thus inhibiting or promoting conformational equilibrium between inactive and active states. According to our results, Nilotinib binding may induce a significant network-bridging effect and enhance centrality of the hot spot residues that stabilize structural environment favored by the specific kinase form. In contrast, Bosutinib and Dasatinib can incur modest changes in the residue interaction network in which ligand binding is primarily coupled only with the identity of the gate-keeper residue. These factors may promote structural adaptability of the active kinase states in binding with these promiscuous inhibitors. Our results have related ligand-induced changes in the residue interaction networks with drug resistance effects, showing that network robustness may be compromised by targeted mutations

  5. Point mutations in the extracytosolic loop between transmembrane segments M5 and M6 of the yeast Pma1 H+-ATPase: alanine-scanning mutagenesis.

    Science.gov (United States)

    Petrov, Valery V

    2015-01-01

    Membrane-spanning segments M4, M5, M6, and M8 of the H(+)-, Ca(2+)-, and K(+), Na(+)-ATPases, which belong to the P2-type pumps are the core through which cations are transported. M5 and M6 loop is a short extracytoplasmic stretch of the seven amino acid residues (714-DNSLDID) connecting two of these segments, M5 and M6, where residues involved in the formation of the proton-binding site(s) are located. In the present study, we have used alanine-scanning mutagenesis to explore the structural and functional relationships within this loop of the yeast plasma membrane Pma1 H(+)-ATPase. Of the 7 Ala mutants made, substitution for the most conserved residue (Leu-717) has led to a severe misfolding and complete block in biogenesis of the mutant enzyme. The replacement of Asp-714 has also caused misfolding leading to significant decrease in the expression of the mutant and loss of activity. The remaining mutants were expressed in secretory vesicles at 21-119% of the wild-type level and were active enough to be analyzed in detail. One of these mutants (I719A) showed five- to threefold decrease in both expression and ATP hydrolyzing and H(+) pumping activities and also threefold reduction in the coupling ratio between ATP hydrolysis and H(+) transport. Thus, Ala substitutions at three positions of the seven seriously affected biogenesis, folding, stability and/or functioning of the enzyme. Taken together, these results lead to suggestion that M5 and M6 loop play an important role in the protein stability and function and is responsible for proper arrangement of transmembrane segments M5 and M6 and probably other domains of the enzyme. Results for additional conserved substitutions (Asn and Glu) at Asp-714 and Asp-720 confirmed this suggestion.

  6. Molecular Determinants Underlying Binding Specificities of the ABL Kinase Inhibitors: Combining Alanine Scanning of Binding Hot Spots with Network Analysis of Residue Interactions and Coevolution

    Science.gov (United States)

    Tse, Amanda; Verkhivker, Gennady M.

    2015-01-01

    Quantifying binding specificity and drug resistance of protein kinase inhibitors is of fundamental importance and remains highly challenging due to complex interplay of structural and thermodynamic factors. In this work, molecular simulations and computational alanine scanning are combined with the network-based approaches to characterize molecular determinants underlying binding specificities of the ABL kinase inhibitors. The proposed theoretical framework unveiled a relationship between ligand binding and inhibitor-mediated changes in the residue interaction networks. By using topological parameters, we have described the organization of the residue interaction networks and networks of coevolving residues in the ABL kinase structures. This analysis has shown that functionally critical regulatory residues can simultaneously embody strong coevolutionary signal and high network centrality with a propensity to be energetic hot spots for drug binding. We have found that selective (Nilotinib) and promiscuous (Bosutinib, Dasatinib) kinase inhibitors can use their energetic hot spots to differentially modulate stability of the residue interaction networks, thus inhibiting or promoting conformational equilibrium between inactive and active states. According to our results, Nilotinib binding may induce a significant network-bridging effect and enhance centrality of the hot spot residues that stabilize structural environment favored by the specific kinase form. In contrast, Bosutinib and Dasatinib can incur modest changes in the residue interaction network in which ligand binding is primarily coupled only with the identity of the gate-keeper residue. These factors may promote structural adaptability of the active kinase states in binding with these promiscuous inhibitors. Our results have related ligand-induced changes in the residue interaction networks with drug resistance effects, showing that network robustness may be compromised by targeted mutations of key mediating

  7. Scanning electrochemical microscopy determination of hydrogen flux at liquid|liquid interface with potentiometric probe

    OpenAIRE

    Jedraszko, Justyna; Nogala, Wojciech; Adamiak, Wojciech; Girault, Hubert H.; Opallo, Marcin

    2014-01-01

    Scanning electrochemical microscopy potentiometric determination of local hydrogen concentration and its flux next to the liquid|liquid interface was demonstrated. This method is based on the shift of open circuit potential of Pt-based reversible hydrogen electrode. The detection system was verified with a system generating hydrogen under galvanostatic conditions. Then, it was applied to aqueous|1,2-dichloroethane interface where hydrogen is produced with decamethylferrocene as electron donor.

  8. STM in liquids. A scanning tunneling microscopy exploration of the liquid-solid interface.

    NARCIS (Netherlands)

    Hulsken, B.

    2008-01-01

    This thesis reports of a series of atomic scale studies of the liquid-solid interface, carried out with a home-built liquid-cell Scanning Tunnelling Microscope (STM). The home-built liquid-cell STM is described in detail, and numerical simulations are performed to show that surfaces immersed in the

  9. Supramolecular chemistry at the liquid/solid interface probed by scanning tunnelling microscopy

    NARCIS (Netherlands)

    Feyter, S. De; Uji-i, H.; Mamdouh, W.; Miura, A.; Zhang, J.; Jonkheijm, P.; Schenning, A.P.H.J.; Meijer, E.W.; Chen, Z.; Wurthner, F.; Schuurmans, N.; Esch, J. van; Feringa, B.L.; Dulcey, A.E.; Percec, V.; Schryver, F.C. De

    2006-01-01

    The liquid/solid interface provides an ideal environment to investigate self-assembly phenomena, and scanning tunnelling microscopy (STM) is one of the preferred methodologies to probe the structure and the properties of physisorbed monolayers on the nanoscale. Physisorbed monolayers are of

  10. Interfacing of the NICP scanning photometer to an ABC-80 microcomputer

    International Nuclear Information System (INIS)

    Sten, T.A.

    The NICP scanning photometer is regularly used in connection with the sounding rocket projects carried out from Andoeya Rocket Range. When dealing with rockets for auroral studies it is essential to follow the development and movements of auroral forms. For this purpose a data screen is superior to a chart for quick evaluation of the exact elevation and density. An ABC-80 microcomputer has therefore been interfaced to the NICP scanning photometer for on-line display of the optical data. This report gives a description of the interfacing as a guide for further programming. Descriptions of two programs are given in Appendix B to illustrate some of the possibilities with the system. The scientific processing of data is, however, considered beyond the scope of this report. The interfaces described can be used with other computer systems provided two 8-bit input ports for data and two 8-bit output ports are available. (Auth.)

  11. Catalytic residues Lys197 and Arg199 of Bacillus subtilis phosphoribosyl diphosphate synthase. Alanine-scanning mutagenesis of the flexible catalytic loop

    DEFF Research Database (Denmark)

    Hove-Jensen, Bjarne; Bentsen, Ann-Kristin K; Harlow, Kenneth W

    2005-01-01

    Eleven of the codons specifying the amino acids of the flexible catalytic loop [KRRPRPNVAEVM(197-208)] of Bacillus subtilis phosphoribosyl diphosphate synthase have been changed individually to specify alanine. The resulting variant enzyme forms, as well as the wildtype enzyme, were produced...... in an Escherichia coli strain lacking endogenous phosphoribosyl diphosphate synthase activity and purified to near homogeneity. The B. subtilis phosphoribosyl diphosphate synthase mutant variants K197A and R199A were studied in detail. The physical properties of the two enzymes were similar to those of the wildtype...

  12. Extracting interface locations in multilayer polymer waveguide films using scanning angle Raman spectroscopy

    International Nuclear Information System (INIS)

    Bobbitt, Jonathan M.; Smith, Emily A.

    2017-01-01

    There is an increasing demand for nondestructive in situ techniques that measure chemical content, total thickness, and interface locations for multilayer polymer films, and SA Raman spectroscopy in combination with appropriate data models can provide this information. A scanning angle (SA) Raman spectroscopy method was developed to measure the chemical composition of multilayer polymer waveguide films and to extract the location of buried interfaces between polymer layers with 7–80-nm axial spatial resolution. The SA Raman method measures Raman spectra as the incident angle of light upon a prism-coupled thin film is scanned. Six multilayer films consisting of poly(methyl methacrylate)/polystyrene or poly(methyl methacrylate)/polystyrene/poly(methyl methacrylate) were prepared with total thicknesses ranging from 330-1260 nm. The interface locations were varied by altering the individual layer thicknesses between 140-680 nm. The Raman amplitude ratio of the 1605 cm -1 peak for PS and 812 cm -1 peak for PMMA was used in calculations of the electric field intensity within the polymer layers to model the SA Raman data and extract the total thickness and interface locations. There is an average 8% and 7% difference in the measured thickness between the SA Raman and profilometry measurements for bilayer and trilayer films, respectively.

  13. A new variable temperature solution-solid interface scanning tunneling microscope.

    Science.gov (United States)

    Jahanbekam, Abdolreza; Mazur, Ursula; Hipps, K W

    2014-10-01

    We present a new solution-solid (SS) interface scanning tunneling microscope design that enables imaging at high temperatures with low thermal drift and with volatile solvents. In this new design, distinct from the conventional designs, the entire microscope is surrounded in a controlled-temperature and controlled-atmosphere chamber. This allows users to take measurements at high temperatures while minimizing thermal drift. By incorporating an open solution reservoir in the chamber, solvent evaporation from the sample is minimized; allowing users to use volatile solvents for temperature dependent studies at high temperatures. The new design enables the user to image at the SS interface with some volatile solvents for long periods of time (>24 h). An increase in the nonlinearity of the piezoelectric scanner in the lateral direction as a function of temperature is addressed. A temperature dependent study of cobalt(II) octaethylporphyrin (CoOEP) at the toluene/Au(111) interface has been performed with this instrument. It is demonstrated that the lattice parameters remain constant within experimental error from 24 °C to 75 °C. Similar quality images were obtained over the entire temperature range. We report the unit cell of CoOEP at the toluene/Au(111) interface (based on two molecules per unit cell) to be A = (1.36 ± 0.04) nm, B = (2.51 ± 0.04) nm, and α = 97° ± 2°.

  14. Haptic-STM: a human-in-the-loop interface to a scanning tunneling microscope.

    Science.gov (United States)

    Perdigão, Luís M A; Saywell, Alex

    2011-07-01

    The operation of a haptic device interfaced with a scanning tunneling microscope (STM) is presented here. The user moves the STM tip in three dimensions by means of a stylus attached to the haptic instrument. The tunneling current measured by the STM is converted to a vertical force, applied to the stylus and felt by the user, with the user being incorporated into the feedback loop that controls the tip-surface distance. A haptic-STM interface of this nature allows the user to feel atomic features on the surface and facilitates the tactile manipulation of the adsorbate/substrate system. The operation of this device is demonstrated via the room temperature STM imaging of C(60) molecules adsorbed on an Au(111) surface in ultra-high vacuum.

  15. In situ scanning probe spectroscopy at nanoscale solid/liquid interfaces

    International Nuclear Information System (INIS)

    Schindler, W.; Hugelmann, M.; Hugelmann, Ph.

    2005-01-01

    Electrochemistry provides unique features for the preparation of low-dimensional structures, but in situ spectroscopy with atomic/molecular resolution at such structures is at present not well established yet. This paper shows that in situ scanning probe spectroscopy at solid/liquid interfaces can be utilized to study electronic properties at nanoscale, if appropriate conditions are applied. Tunneling spectroscopy provides information about tunneling barrier heights and electronic states in the tunneling gap, as shown on Au(1 1 1) substrates, contact spectroscopy allows for transport measurements at single nanostructures, as shown at Au/n-Si(1 1 1) nanodiodes. The influence of the electrolytic environment on spectroscopic investigations is not a principal limitation, but offers additional degrees of freedom, which allow, for example, spectroscopic studies of potential dependent surface phenomena at solid/liquid interfaces

  16. Alanine water complexes.

    Science.gov (United States)

    Vaquero, Vanesa; Sanz, M Eugenia; Peña, Isabel; Mata, Santiago; Cabezas, Carlos; López, Juan C; Alonso, José L

    2014-04-10

    Two complexes of alanine with water, alanine-(H2O)n (n = 1,2), have been generated by laser ablation of the amino acid in a supersonic jet containing water vapor and characterized using Fourier transform microwave spectroscopy. In the observed complexes, water molecules bind to the carboxylic group of alanine acting as both proton donors and acceptors. In alanine-H2O, the water molecule establishes two intermolecular hydrogen bonds forming a six-membered cycle, while in alanine-(H2O)2 the two water molecules establish three hydrogen bonds forming an eight-membered ring. In both complexes, the amino acid moiety is in its neutral form and shows the conformation observed to be the most stable for the bare molecule. The microsolvation study of alanine-(H2O)n (n = 1,2) can be taken as a first step toward understanding bulk properties at a microscopic level.

  17. Local impedance measurement of an electrode/single-pentacene-grain interface by frequency-modulation scanning impedance microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Tomoharu; Yamada, Hirofumi, E-mail: h-yamada@kuee.kyoto-u.ac.jp [Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510 (Japan); Kobayashi, Kei [Department of Electronic Science and Engineering, Kyoto University, Kyoto 615-8510 (Japan); The Hakubi Center for Advanced Research, Kyoto University, Kyoto 615-8520 (Japan)

    2015-08-07

    The device performances of organic thin film transistors are often limited by the metal–organic interface because of the disordered molecular layers at the interface and the energy barriers against the carrier injection. It is important to study the local impedance at the interface without being affected by the interface morphology. We combined frequency modulation atomic force microscopy with scanning impedance microscopy (SIM) to sensitively measure the ac responses of the interface to an ac voltage applied across the interface and the dc potential drop at the interface. By using the frequency-modulation SIM (FM-SIM) technique, we characterized the interface impedance of a Pt electrode and a single pentacene grain as a parallel circuit of a contact resistance and a capacitance. We found that the reduction of the contact resistance was caused by the reduction of the energy level mismatch at the interface by the FM-SIM measurements, demonstrating the usefulness of the FM-SIM technique for investigation of the local interface impedance without being affected by its morphology.

  18. Dynamic covalent chemistry of bisimines at the solid/liquid interface monitored by scanning tunnelling microscopy.

    Science.gov (United States)

    Ciesielski, Artur; El Garah, Mohamed; Haar, Sébastien; Kovaříček, Petr; Lehn, Jean-Marie; Samorì, Paolo

    2014-11-01

    Dynamic covalent chemistry relies on the formation of reversible covalent bonds under thermodynamic control to generate dynamic combinatorial libraries. It provides access to numerous types of complex functional architectures, and thereby targets several technologically relevant applications, such as in drug discovery, (bio)sensing and dynamic materials. In liquid media it was proved that by taking advantage of the reversible nature of the bond formation it is possible to combine the error-correction capacity of supramolecular chemistry with the robustness of covalent bonding to generate adaptive systems. Here we show that double imine formation between 4-(hexadecyloxy)benzaldehyde and different α,ω-diamines as well as reversible bistransimination reactions can be achieved at the solid/liquid interface, as monitored on the submolecular scale by in situ scanning tunnelling microscopy imaging. Our modular approach enables the structurally controlled reversible incorporation of various molecular components to form sophisticated covalent architectures, which opens up perspectives towards responsive multicomponent two-dimensional materials and devices.

  19. Interface-induced chiral domain walls, spin spirals and skyrmions revealed by spin-polarized scanning tunneling microscopy.

    Science.gov (United States)

    von Bergmann, Kirsten; Kubetzka, André; Pietzsch, Oswald; Wiesendanger, Roland

    2014-10-01

    The spin textures of ultra-thin magnetic layers exhibit surprising variety. The loss of inversion symmetry at the interface of the magnetic layer and substrate gives rise to the so-called Dzyaloshinskii-Moriya interaction which favors non-collinear spin arrangements with unique rotational sense. Here we review the application of spin-polarized scanning tunneling microscopy to such systems, which has led to the discovery of interface-induced chiral domain walls and spin spirals. Recently, different interface-driven skyrmion lattices have been found, and the writing as well as the deleting of individual skyrmions based on local spin-polarized current injection has been demonstrated. These interface-induced non-collinear magnetic states offer new exciting possibilities to study fundamental magnetic interactions and to tailor material properties for spintronic applications.

  20. Comparative Functional Alanine Positional Scanning of the α-Melanocyte Stimulating Hormone and NDP-Melanocyte Stimulating Hormone Demonstrates Differential Structure-Activity Relationships at the Mouse Melanocortin Receptors.

    Science.gov (United States)

    Todorovic, Aleksandar; Ericson, Mark D; Palusak, Ryan D; Sorensen, Nicholas B; Wood, Michael S; Xiang, Zhimin; Haskell-Luevano, Carrie

    2016-07-20

    The melanocortin system has been implicated in the regulation of various physiological functions including melanogenesis, steroidogenesis, energy homeostasis, and feeding behavior. Five melanocortin receptors have been identified to date and belong to the family of G protein-coupled receptors (GPCR). Post-translational modification of the proopiomelanocortin (POMC) prohormone leads to the biosynthesis of the endogenous melanocortin agonists, including α-melanocyte stimulating hormone (α-MSH), β-MSH, γ-MSH, and adrenocorticotropic hormone (ACTH). All the melanocortin agonists derived from the POMC prohormone contain a His-Phe-Arg-Trp tetrapeptide sequence that has been implicated in eliciting the pharmacological responses at the melanocortin receptors. Herein, an alanine (Ala) positional scan is reported for the endogenous α-MSH ligand and the synthetic, more potent, NDP-MSH peptide (Ac-Ser(1)-Tyr(2)-Ser(3)-Nle(4)-Glu(5)-His(6)-DPhe(7)-Arg(8)-Trp(9)-Gly(10)-Lys(11)-Pro(12)-Val(13)-NH2) at the cloned mouse melanocortin receptors to test the assumption that the structure-activity relationships of one ligand would apply to the other. Several residues outside of the postulated pharmacophore altered potency at the melanocortin receptors, most notably the 1560-, 37-, and 15-fold potency loss when the Glu(5) position of α-MSH was substituted with Ala at the mMC1R, mMC3R, and mMC4R, respectively. Importantly, the altered potencies due to Ala substitutions in α-MSH did not necessarily correlate with equivalent Ala substitutions in NDP-MSH, indicating that structural modifications and corresponding biological activities in one of these melanocortin ligands may not be predictive for the other agonist.

  1. Scanning tunnelling microscopy of a foldamer prototype at the liquid/solid interface : water/Au(111) versus 1-octanol/graphite

    NARCIS (Netherlands)

    Klymchenko, Andrey S.; Schuurmans, Norbert; van der Auweraer, Mark; Feringa, Ben L.; van Esch, Jan; De Feyter, Steven

    2006-01-01

    We report the design and synthesis of a catechol based foldamer containing amide functionalized alkyl chains, and its monolayer formation at the liquid/solid interface. By scanning tunnelling microscopy, both at the 1-octanol/graphite interface as well as at the water/Au( 111) interface, the

  2. Dosimetric comparison on tissue interfaces with TLD dosimeters, L-alanine, EDR2 films and Penelope simulation for a Co-60 source and linear accelerator in radiotherapy; Comparacion dosimetrica en interfaces de tejidos con dosimetros TLD, L-alanina, peliculas EDR2 y simulacion Penelope para una fuente de Co-60 y acelerador lineal en radioterapia

    Energy Technology Data Exchange (ETDEWEB)

    Vega R, J. L.; Cayllahua, F.; Apaza, D. G.; Javier, H., E-mail: josevegaramirez@yahoo.es [Universidad Nacional de San Agustin, Departamento de Fisica, Av. Independencia s/n, Arequipa (Peru)

    2015-10-15

    Percentage depth dose curves were obtained with TLD-100 dosimeters, EDR2 films and Penelope simulation at the interfaces in an inhomogeneous mannequin, composed by equivalent materials to the human body built for this study, consisting of cylindrical plates of solid water-bone-lung-bone-solid water of 15 cm in diameter and 1 cm in height; plates were placed in descending way (4-2-8-2-4). Irradiated with Co-60 source (Theratron Equinox-100) for small radiation fields 3 x 3 cm{sup 2} and 1 x 1 cm{sup 2} at a surface source distance of 100 cm from mannequin. The TLD-100 dosimeters were placed in the center of each plate of mannequin irradiated at 10 Gy. The results were compared between these measurement techniques, giving good agreement in interfaces better than 97%. This study was compared with the same characteristics of another study realized with other equivalent materials to human body not homogeneous acrylic-bone-cork-bone-acrylic. The percentage depth dose curves were obtained with mini-dosimeters L-alanine of 1 mm in diameter and 3 mm in height and 3.5 to 4.0 mg of mass with spectrometer band K (EPR). The mini-dosimeters were irradiated with a lineal accelerator PRIMUS Siemens 6 MV. The results of percentage depth dose of L-alanine mini-dosimeters show a good agreement with the percentage depth dose curves of Penelope code, better than 97.7% in interfaces of tissues. (Author)

  3. Alanine transaminase (ALT) blood test

    Science.gov (United States)

    ... gov/ency/article/003473.htm Alanine transaminase (ALT) blood test To use the sharing features on this page, please enable JavaScript. The alanine transaminase (ALT) blood test measures the level of the enzyme ALT in ...

  4. Design of Deinococcus radiodurans thioredoxin reductase with altered thioredoxin specificity using computational alanine mutagenesis

    OpenAIRE

    Obiero, Josiah; Sanders, David AR

    2011-01-01

    In this study, the X-ray crystal structure of the complex between Escherichia coli thioredoxin reductase (EC TrxR) and its substrate thioredoxin (Trx) was used as a guide to design a Deinococcus radiodurans TrxR (DR TrxR) mutant with altered Trx specificity. Previous studies have shown that TrxRs have higher affinity for cognate Trxs (same species) than that for Trxs from different species. Computational alanine scanning mutagenesis and visual inspection of the EC TrxR–Trx interface suggested...

  5. Promoter scanning of the human COX-2 gene with 8-ring polyamides: unexpected weakening of polyamide-DNA binding and selectivity by replacing an internal N-Me-pyrrole with β-alanine.

    Science.gov (United States)

    Bashkin, James K; Aston, Karl; Ramos, Joseph P; Koeller, Kevin J; Nanjunda, Rupesh; He, Gaofei; Dupureur, Cynthia M; David Wilson, W

    2013-02-01

    Rules for polyamide-DNA recognition have proved invaluable for the design of sequence-selective DNA binding agents in cell-free systems. However, these rules are not fully transferrable to predicting activity in cells, tissues or animals, and additional refinements to our understanding of DNA recognition would help biomedical studies. Similar complexities are encountered when using internal β-alanines as polyamide building blocks in place of N-methylpyrrole; β-alanines were introduced in polyamide designs to maintain good hydrogen bonding registry with the target DNA, especially for long polyamides or those with several GC bp (P.B. Dervan, A.R. Urbach, Essays Contemp. Chem. (2001) 327-339). Thus, to clarify important subtleties of molecular recognition, we studied the effects of replacing a single pyrrole with β-alanine in 8-ring polyamides designed against the Ets-1 transcription factor. Replacement of a single internal N-methylpyrrole with β-alanine to generate a β/Im pairing in two 8-ring polyamides causes a decrease in DNA binding affinity by two orders of magnitude and decreases DNA binding selectivity, contrary to expectations based on the literature. Measurements were made by fluorescence spectroscopy, quantitative DNA footprinting and surface plasmon resonance, with these vastly different techniques showing excellent agreement. Furthermore, results were validated for a range of DNA substrates from small hairpins to long dsDNA sequences. Docking studies helped show that β-alanine does not make efficient hydrophobic contacts with the rest of the polyamide or nearby DNA, in contrast to pyrrole. These results help refine design principles and expectations for polyamide-DNA recognition. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  6. Relating Linear and Volumetric Variables Through Body Scanning to Improve Human Interfaces in Space

    Science.gov (United States)

    Margerum, Sarah E.; Ferrer, Mike A.; Young, Karen S.; Rajulu, Sudhakar

    2010-01-01

    Designing space suits and vehicles for the diverse human population present unique challenges for the methods of traditional anthropometry. Space suits are bulky and allow the operator to shift position within the suit and inhibit the ability to identify body landmarks. Limited suit sizing options also cause variability in fit and performance between similarly sized individuals. Space vehicles are restrictive in volume in both the fit and the ability to collect data. NASA's Anthropometric and Biomechanics Facility (ABF) has utilized 3D scanning to shift from traditional linear anthropometry to explore and examine volumetric capabilities to provide anthropometric solutions for design. Overall, the key goals are to improve the human-system performance and develop new processes to aid in the design and evaluation of space systems. Four case studies are presented that illustrate the shift from purely linear analyses to an augmented volumetric toolset to predict and analyze the human within the space suit and vehicle. The first case study involves the calculation of maximal head volume to estimate total free volume in the helmet for proper air exchange. Traditional linear measurements resulted in an inaccurate representation of the head shape, yet limited data exists for the determination of a large head volume. Steps were first taken to identify and classify a maximum head volume and the resulting comparisons to the estimate are presented in this paper. This study illustrates the gap between linear components of anthropometry and the need for overall volume metrics in order to provide solutions. A second case study examines the overlay of the space suit scans and components onto scanned individuals to quantify fit and clearance to aid in sizing the suit to the individual. Restrictions in space suit size availability present unique challenges to optimally fit the individual within a limited sizing range while maintaining performance. Quantification of the clearance and

  7. The Use Of Scanning Probe Microscopy To Investigate Crystal-Fluid Interfaces

    International Nuclear Information System (INIS)

    Orme, C A; Giocondi, J L

    2007-01-01

    Over the past decade there has been a natural drive to extend the investigation of dynamic surfaces in fluid environments to higher resolution characterization tools. Various aspects of solution crystal growth have been directly visualized for the first time. These include island nucleation and growth using transmission electron microscopy and scanning tunneling microscopy; elemental step motion using scanning probe microscopy; and the time evolution of interfacial atomic structure using various diffraction techniques. In this lecture we will discuss the use of one such in situ method, scanning probe microscopy, as a means of measuring surface dynamics during crystal growth and dissolution. We will cover both practical aspects of imaging such as environmental control, fluid flow, and electrochemical manipulation, as well as the types of physical measurements that can be made. Measurements such as step motion, critical lengths, nucleation density, and step fluctuations, will be put in context of the information they provide about mechanistic processes at surfaces using examples from metal and mineral crystal growth

  8. Exceptionally Slow Movement of Gold Nanoparticles at a Solid/Liquid Interface Investigated by Scanning Transmission Electron Microscopy.

    Science.gov (United States)

    Verch, Andreas; Pfaff, Marina; de Jonge, Niels

    2015-06-30

    Gold nanoparticles were observed to move at a liquid/solid interface 3 orders of magnitude slower than expected for the movement in a bulk liquid by Brownian motion. The nanoscale movement was studied with scanning transmission electron microscopy (STEM) using a liquid enclosure consisting of microchips with silicon nitride windows. The experiments involved a variation of the electron dose, the coating of the nanoparticles, the surface charge of the enclosing membrane, the viscosity, and the liquid thickness. The observed slow movement was not a result of hydrodynamic hindrance near a wall but instead explained by the presence of a layer of ordered liquid exhibiting a viscosity 5 orders of magnitude larger than a bulk liquid. The increased viscosity presumably led to a dramatic slowdown of the movement. The layer was formed as a result of the surface charge of the silicon nitride windows. The exceptionally slow motion is a crucial aspect of electron microscopy of specimens in liquid, enabling a direct observation of the movement and agglomeration of nanoscale objects in liquid.

  9. Immersion-scanning-tunneling-microscope for long-term variable-temperature experiments at liquid-solid interfaces

    Science.gov (United States)

    Ochs, Oliver; Heckl, Wolfgang M.; Lackinger, Markus

    2018-05-01

    Fundamental insights into the kinetics and thermodynamics of supramolecular self-assembly on surfaces are uniquely gained by variable-temperature high-resolution Scanning-Tunneling-Microscopy (STM). Conventionally, these experiments are performed with standard ambient microscopes extended with heatable sample stages for local heating. However, unavoidable solvent evaporation sets a technical limit on the duration of these experiments, hence prohibiting long-term experiments. These, however, would be highly desirable to provide enough time for temperature stabilization and settling of drift but also to study processes with inherently slow kinetics. To overcome this dilemma, we propose a STM that can operate fully immersed in solution. The instrument is mounted onto the lid of a hermetically sealed heatable container that is filled with the respective solution. By closing the container, both the sample and microscope are immersed in solution. Thereby solvent evaporation is eliminated and an environment for long-term experiments with utmost stable and controllable temperatures between room-temperature and 100 °C is provided. Important experimental requirements for the immersion-STM and resulting design criteria are discussed, the strategy for protection against corrosive media is described, the temperature stability and drift behavior are thoroughly characterized, and first long-term high resolution experiments at liquid-solid interfaces are presented.

  10. Structural features and kinetic characterization of alanine racemase from Bacillus pseudofirmus OF4.

    Science.gov (United States)

    Dong, Hui; Hu, Tingting; He, Guangzheng; Lu, Deren; Qi, Jianxun; Dou, Yanshu; Long, Wei; He, Xin; Ju, Jiansong; Su, Dan

    2018-02-26

    Alanine racemase (Alr) is a pyridoxal-5'-phosphate-dependent (PLP) enzyme that catalyzes a reversible racemization between the enantiomers of alanine. d-Alanine is an indispensable constituent in the biosynthesis of bacterial cell-wall peptidoglycan, and its inhibition is lethal to prokaryotes, which makes it an attractive target for designing antibacterial drugs. In this study, the molecular structure of alanine racemase from Bacillus pseudofirmus OF4 (DadX OF4 ) was determined by X-ray crystallography to a resolution of 1.8 Å. The comparison of DadX OF4 with alanine racemases from other bacteria demonstrated a conserved overall fold. Enzyme kinetics analysis showed that the conserved residues at the substrate entryway and the salt bridge at the dimer interface are critical for enzyme activity. These structural and biochemical findings provide a template for future structure-based drug-development efforts targeting alanine racemases. Copyright © 2018 Elsevier Inc. All rights reserved.

  11. Negative compressibility at LaAlO{sub 3}/SrTiO{sub 3} interfaces explored with scanning force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tinkl, Veronika; Breitschaft, Martin; Hammerl, German; Kopp, Thilo [Experimentalphysik VI, Zentrum fuer Elektronische Korrelationen und Magnetismus, Universitaet Augsburg, Augsburg (Germany); Richter, Christoph; Mannhart, Jochen [Experimentalphysik VI, Zentrum fuer Elektronische Korrelationen und Magnetismus, Universitaet Augsburg, Augsburg (Germany); Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)

    2012-07-01

    The interface between the band insulators LaAlO{sub 3} and SrTiO{sub 3} is currently one of the most actively investigated structures in the field of oxide interfaces. If the LaAlO{sub 3}-film thickness exceeds three unit cells on a TiO{sub 2}-terminated SrTiO{sub 3} substrate a conducting layer is formed at the interface. This conducting layer can be driven insulating by electric fields. In this presentation we demonstrate that the interface exhibits negative compressibility as the carrier density is reduced. We investigated interfaces consisting of four unit cells LaAlO{sub 3} with a low temperature ultra-high vacuum scanning probe microscope. Contact potential difference measurements were performed at various carrier densities of the interface electron system. The difference in the work functions of interface and tip depends on the applied electric field. We show that the chemical potential at the interface increases with decreasing carrier density. This effect is caused by electron-electron interactions and corresponds to a negative compressibility. The negative compressibility gives rise to applications by, for example, making use of the resulting large enhancement of the capacitance.

  12. Dose response of alanine and methyl alanine towards gamma and in-situ alpha irradiation

    International Nuclear Information System (INIS)

    Mohapatra, M.; Rajeswari, B.; Bhide, M.K.; Rane, Vinayak; Kadam, R.M.

    2017-01-01

    In situ alpha and external gamma dose response of two ESR (electron spin resonance) dosimetric materials namely alanine and methyl alanine were investigated. It was observed that alanine dosimeter had a better dose response in comparison to methyl alanine for the in-situ alpha irradiation by using 239 Pu powder. On the other hand, in case of gamma radiation, methyl alanine was found to have the sensitivity as twice that of alanine. (author)

  13. EPR/alanine dosimetry for two therapeutic proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Marrale, Maurizio, E-mail: maurizio.marrale@unipa.it [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Carlino, Antonio [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); EBG MedAustron GmbH, Marie Curie-Straße 5, A-2700 Wiener Neustadt (Austria); Gallo, Salvatore [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Laboratorio PH3DRA, Dipartimento di Fisica e Astronomia, Università di Catania, Via Santa Sofia 64, 95123 Catania (Italy); Longo, Anna; Panzeca, Salvatore [Dipartimento di Fisica e Chimica, Università di Palermo, Viale delle Scienze, Edificio 18, 90128 Palermo (Italy); Gruppo V Sezione INFN di Catania, Via Santa Sofia, 64, 95123 Catania (Italy); Bolsi, Alessandra; Hrbacek, Jan; Lomax, Tony [Center for Proton Therapy, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

    2016-02-01

    In this work the analysis of the electron paramagnetic resonance (EPR) response of alanine pellets exposed to two different clinical proton beams employed for radiotherapy is performed. One beam is characterized by a passive delivery technique and is dedicated to the eyes treatment (OPTIS2 beam line). Alanine pellets were irradiated with a 70 MeV proton beam corresponding to 35 mm range in eye tissue. We investigated how collimators with different sizes and shape used to conform the dose to the planned target volume influence the delivered dose. For this purpose we performed measurements with varying the collimator size (Output Factor) and the results were compared with those obtained with other dosimetric techniques (such as Markus chamber and diode detector). This analysis showed that the dosimeter response is independent of collimator diameter if this is larger than or equal to 10 mm. The other beam is characterized by an active spot-scanning technique, the Gantry1 beam line (maximum energy 230 MeV), and is used to treat deep-seated tumors. The dose linearity of alanine response in the clinical dose range was tested and the alanine dose response at selected locations in depth was measured and compared with the TPS planned dose in a quasi-clinical scenario. The alanine response was found to be linear in the dose in the clinical explored range (from 10 to 70 Gy). Furthermore, a depth dose profile in a quasi-clinical scenario was measured and compared to the dose computed by the Treatment Planning System PSIPLAN. The comparison of calibrated proton alanine measurements and TPS dose shows a difference under 1% in the SOBP and a “quenching” effect up to 4% in the distal part of SOBP. The positive dosimetric characteristics of the alanine pellets confirm the feasibility to use these detectors for “in vivo” dosimetry in clinical proton beams.

  14. EPR/alanine dosimetry for two therapeutic proton beams

    International Nuclear Information System (INIS)

    Marrale, Maurizio; Carlino, Antonio; Gallo, Salvatore; Longo, Anna; Panzeca, Salvatore; Bolsi, Alessandra; Hrbacek, Jan; Lomax, Tony

    2016-01-01

    In this work the analysis of the electron paramagnetic resonance (EPR) response of alanine pellets exposed to two different clinical proton beams employed for radiotherapy is performed. One beam is characterized by a passive delivery technique and is dedicated to the eyes treatment (OPTIS2 beam line). Alanine pellets were irradiated with a 70 MeV proton beam corresponding to 35 mm range in eye tissue. We investigated how collimators with different sizes and shape used to conform the dose to the planned target volume influence the delivered dose. For this purpose we performed measurements with varying the collimator size (Output Factor) and the results were compared with those obtained with other dosimetric techniques (such as Markus chamber and diode detector). This analysis showed that the dosimeter response is independent of collimator diameter if this is larger than or equal to 10 mm. The other beam is characterized by an active spot-scanning technique, the Gantry1 beam line (maximum energy 230 MeV), and is used to treat deep-seated tumors. The dose linearity of alanine response in the clinical dose range was tested and the alanine dose response at selected locations in depth was measured and compared with the TPS planned dose in a quasi-clinical scenario. The alanine response was found to be linear in the dose in the clinical explored range (from 10 to 70 Gy). Furthermore, a depth dose profile in a quasi-clinical scenario was measured and compared to the dose computed by the Treatment Planning System PSIPLAN. The comparison of calibrated proton alanine measurements and TPS dose shows a difference under 1% in the SOBP and a “quenching” effect up to 4% in the distal part of SOBP. The positive dosimetric characteristics of the alanine pellets confirm the feasibility to use these detectors for “in vivo” dosimetry in clinical proton beams.

  15. Alanine-EPR dosimetry system for high industrial as well radiotherapeutic dose measurement

    International Nuclear Information System (INIS)

    Dobrovodsky, J.; Bukovjan, J.

    2005-01-01

    Slovak Institute of Metrology is developing new metrology standard for high doses, based on the alanine-EPR as a reference dosimetry system. A Bruker e-scan EPR analyser developed specifically for alanine dosimetry has improved stability of EPR measurement, especially at lower dose range. The standard e-scan system provides sensitivity below 1 Gray. After further improvement of the system and lowering of dose determination expanded uncertainty down below 1 %, its utilisation for radiotherapy field is expected (authors)

  16. In-situ Study of Dynamic Phenomena at Metal Nanosolder Interfaces Using Aberration Corrected Scanning Transmission Electron Microcopy.

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Ping

    2014-10-01

    Controlling metallic nanoparticle (NP) interactions plays a vital role in the development of new joining techniques (nanosolder) that bond at lower processing temperatures but remain viable at higher temperatures. The pr imary objective of this project is t o develop a fundamental understanding of the actual reaction processes, associated atomic mechanisms, and the resulting microstructure that occur during thermally - driven bond formation concerning metal - metal nano - scale (%3C50nm) interfaces. In this LDRD pr oject, we have studied metallic NPs interaction at the elevated temperatures by combining in - situ transmission electron microscopy (TEM ) using an aberration - corrected scanning transmission electron microscope (AC - STEM) and atomic - scale modeling such as m olecular dynamic (MD) simulations. Various metallic NPs such as Ag, Cu and Au are synthesized by chemical routines. Numerous in - situ e xperiments were carried out with focus of the research on study of Ag - Cu system. For the first time, using in - situ STEM he ating experiments , we directly observed t he formation of a 3 - dimensional (3 - D) epitaxial Cu - Ag core - shell nanoparticle during the thermal interaction of Cu and Ag NPs at elevated temperatures (150 - 300 o C). The reaction takes place at temperatures as low as 150 o C and was only observed when care was taken to circumvent the effects of electron beam irradiation during STEM imaging. Atomic - scale modeling verified that the Cu - Ag core - shell structure is energetically favored, and indicated that this phenomenon is a nano - scale effect related to the large surface - to - volume ratio of the NPs. The observation potentially can be used for developing new nanosolder technology that uses Ag shell as the "glue" that stic ks the particles of Cu together. The LDRD has led to several journal publications and numerous conference presentations, and a TA. In addition, we have developed new TEM characterization techniques and phase

  17. Alanine-polymer dosemeter of ionizing radiation

    International Nuclear Information System (INIS)

    Tomasinski, Z.; Mirkowski, K.; Panta, P.; Stachowicz, W.

    1994-01-01

    The method of chemical preparation of alanine-copolymer of ethylene and vinyl acetate has been worked out. The material has been in a form of rods. The content of alanine has not exceeded 30%. The ESR signal of alanine radicals has been detected after exposition to ionizing radiation. The dose-response relationship has been presented

  18. 21 CFR 582.5118 - Alanine.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Alanine. 582.5118 Section 582.5118 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... § 582.5118 Alanine. (a) Product. Alanine (L- and DL-forms). (b) Conditions of use. This substance is...

  19. Cryo-Scanning Electron Microscopy (SEM) and Scanning Transmission Electron Microscopy (STEM)-in-SEM for Bio- and Organo-Mineral Interface Characterization in the Environment.

    Science.gov (United States)

    Wille, Guillaume; Hellal, Jennifer; Ollivier, Patrick; Richard, Annie; Burel, Agnes; Jolly, Louis; Crampon, Marc; Michel, Caroline

    2017-12-01

    Understanding biofilm interactions with surrounding substratum and pollutants/particles can benefit from the application of existing microscopy tools. Using the example of biofilm interactions with zero-valent iron nanoparticles (nZVI), this study aims to apply various approaches in biofilm preparation and labeling for fluorescent or electron microscopy and energy dispersive X-ray spectrometry (EDS) microanalysis for accurate observations. According to the targeted microscopy method, biofilms were sampled as flocs or attached biofilm, submitted to labeling using 4',6-diamidino-2-phenylindol, lectins PNA and ConA coupled to fluorescent dye or gold nanoparticles, and prepared for observation (fixation, cross-section, freezing, ultramicrotomy). Fluorescent microscopy revealed that nZVI were embedded in the biofilm structure as aggregates but the resolution was insufficient to observe individual nZVI. Cryo-scanning electron microscopy (SEM) observations showed nZVI aggregates close to bacteria, but it was not possible to confirm direct interactions between nZVI and cell membranes. Scanning transmission electron microscopy in the SEM (STEM-in-SEM) showed that nZVI aggregates could enter the biofilm to a depth of 7-11 µm. Bacteria were surrounded by a ring of extracellular polymeric substances (EPS) preventing direct nZVI/membrane interactions. STEM/EDS mapping revealed a co-localization of nZVI aggregates with lectins suggesting a potential role of EPS in nZVI embedding. Thus, the combination of divergent microscopy approaches is a good approach to better understand and characterize biofilm/metal interactions.

  20. The effect of four user interface concepts on visual scan pattern similarity and information foraging in a complex decision making task.

    Science.gov (United States)

    Starke, Sandra D; Baber, Chris

    2018-07-01

    User interface (UI) design can affect the quality of decision making, where decisions based on digitally presented content are commonly informed by visually sampling information through eye movements. Analysis of the resulting scan patterns - the order in which people visually attend to different regions of interest (ROIs) - gives an insight into information foraging strategies. In this study, we quantified scan pattern characteristics for participants engaging with conceptually different user interface designs. Four interfaces were modified along two dimensions relating to effort in accessing information: data presentation (either alpha-numerical data or colour blocks), and information access time (all information sources readily available or sequential revealing of information required). The aim of the study was to investigate whether a) people develop repeatable scan patterns and b) different UI concepts affect information foraging and task performance. Thirty-two participants (eight for each UI concept) were given the task to correctly classify 100 credit card transactions as normal or fraudulent based on nine transaction attributes. Attributes varied in their usefulness of predicting the correct outcome. Conventional and more recent (network analysis- and bioinformatics-based) eye tracking metrics were used to quantify visual search. Empirical findings were evaluated in context of random data and possible accuracy for theoretical decision making strategies. Results showed short repeating sequence fragments within longer scan patterns across participants and conditions, comprising a systematic and a random search component. The UI design concept showing alpha-numerical data in full view resulted in most complete data foraging, while the design concept showing colour blocks in full view resulted in the fastest task completion time. Decision accuracy was not significantly affected by UI design. Theoretical calculations showed that the difference in achievable

  1. Observation of two-dimensional p-type dopant diffusion across a p+-InP/n–-InGaAs interface using scanning electron microscopy

    International Nuclear Information System (INIS)

    Tsurumi, Daisuke; Hamada, Kotaro; Kawasaki, Yuji

    2013-01-01

    Scanning electron microscopy (SEM) with potential calculations has been shown to be effective for the detection of p-type dopant diffusion, even across a Zn doped p + -InP/non-doped n – -InGaAs/n + -InP heterojunction. Heterojunction samples were observed using SEM and the electrostatic potential was calculated from Zn concentration profiles obtained by secondary ion mass spectrometry. The sensitivity of SEM for the potential was derived from the SEM observations and potential calculation results. The results were then used to investigate the dependence of the SEM contrast on the Zn diffusion length across the p + -InP/non-doped n – -InGaAs interface. Accurate dopant mapping was difficult when the Zn diffusion length was shorter than 30 nm, because the heterojunction affects the potential at the interface. However, accurate dopant mapping was possible when the Zn diffusion length was longer than 30 nm, because the factor dominating the potential variation was not the heterojunction, but rather Zn diffusion 30 nm distant from the interface. Thus, Zn diffusion further than 30 nm from a Zn-doped p + -InP/non-doped n – -InGaAs interface can be effectively detected by secondary electron (SE) imaging. SE imaging with potential calculations can be widely used for accurate dopant mapping, even at heterojunctions, and is, therefore, expected to be of significant assistance to the compound semiconductor industry.

  2. The result of Alanine/ESR dosimetry at Wolsung unit 1

    International Nuclear Information System (INIS)

    Park, Byeong Ryong; Choi, Hoon; Lim, Young Khi

    2008-01-01

    It needs accurate estimation of radiation level for verifying machinery and cable in Nuclear Power Plant. Therefore, in this study, we used ESR(Electron Spin Resonance) system for estimate dose of Alanine dosimeter. Alanine/ESR dosimetry, already known as a dosimetric method in medical and industrial field, was applied to estimate dose quantity at cable locations within a nuclear power plant as a part of equipment qualification program. Alanine/ESR dosimetry of absorbed dose range is 1 - 100 KGy. The alanine dosimeter is not significantly affected by temperature and fading is limited to 1% per year. The alanine dosimeters were fixed on the targeted cable or nearest position to measure dose quantity to get accurate value. Alanine dosimeters were scanned by commercially used two different ESR systems, e-scan and EMX series for alanine dosimeters. To estimate more accurate dose, two environmental correction factors, irradiation temperature and dosimeter weight, were used in calculation of absorbed dose quantity. In this study, dose values which are alinine dosimeter from Wolsong unit 1 are measured by two ESR systems. And then the results was compared each other

  3. MetAlign: Interface-Driven, Versatile Metabolomics Tool for Hyphenated Full-Scan Mass Spectrometry Data Preprocessing

    NARCIS (Netherlands)

    Lommen, A.

    2009-01-01

    Hyphenated full-scan MS technology creates large amounts of data. A versatile easy to handle automation tool aiding in the data analysis is very important in handling such a data stream. MetAlign software-as described in this manuscript-handles a broad range of accurate mass and nominal mass GC/MS

  4. Catalytic Stereoinversion of L-Alanine to Deuterated D-Alanine.

    Science.gov (United States)

    Moozeh, Kimia; So, Soon Mog; Chin, Jik

    2015-08-03

    A combination of an achiral pyridoxal analogue and a chiral base has been developed for catalytic deuteration of L-alanine with inversion of stereochemistry to give deuterated D-alanine under mild conditions (neutral pD and 25 °C) without the use of any protecting groups. This system can also be used for catalytic deuteration of D-alanine with retention of stereochemistry to give deuterated D-alanine. Thus a racemic mixture of alanine can be catalytically deuterated to give an enantiomeric excess of deuterated D-alanine. While catalytic deracemization of alanine is forbidden by the second law of thermodynamics, this system can be used for catalytic deracemization of alanine with deuteration. Such green and biomimetic approach to catalytic stereocontrol provides insights into efficient amino acid transformations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. beta-Chloro-L-alanine inhibition of the Escherichia coli alanine-valine transaminase.

    OpenAIRE

    Whalen, W A; Wang, M D; Berg, C M

    1985-01-01

    beta-Chloro-L-alanine, an amino acid analog which inhibits a number of enzymes, reversibly inhibited the Escherichia coli K-12 alanine-valine transaminase, transaminase C. This inhibition, along with the inhibition of transaminase B, accounted for the isoleucine-plus-valine requirement of E. coli in the presence of beta-chloro-L-alanine.

  6. Lock-in thermography, penetrant inspection, and scanning electron microscopy for quantitative evaluation of open micro-cracks at the tooth-restoration interface

    Science.gov (United States)

    Streza, M.; Hodisan, I.; Prejmerean, C.; Boue, C.; Tessier, Gilles

    2015-03-01

    The evaluation of a dental restoration in a non-invasive way is of paramount importance in clinical practice. The aim of this study was to assess the minimum detectable open crack at the cavity-restorative material interface by the lock-in thermography technique, at laser intensities which are safe for living teeth. For the analysis of the interface, 18 box-type class V standardized cavities were prepared on the facial and oral surfaces of each tooth, with coronal margins in enamel and apical margins in dentine. The preparations were restored with the Giomer Beautifil (Shofu) in combination with three different adhesive systems. Three specimens were randomly selected from each experimental group and each slice has been analysed by visible, infrared (IR), and scanning electron microscopy (SEM). Lock-in thermography showed the most promising results in detecting both marginal and internal defects. The proposed procedure leads to a diagnosis of micro-leakages having openings of 1 µm, which is close to the diffraction limit of the IR camera. Clinical use of a thermographic camera in assessing the marginal integrity of a restoration becomes possible. The method overcomes some drawbacks of standard SEM or dye penetration testing. The results support the use of an IR camera in dentistry, for the diagnosis of micro-gaps at bio-interfaces.

  7. Alanine metabolism in acute falciparum malaria

    NARCIS (Netherlands)

    Pukrittayakamee, S.; Krishna, S.; ter Kuile, F.; Wilaiwan, O.; Williamson, D. H.; White, N. J.

    2002-01-01

    We investigated the integrity of the gluconeogenic pathway in severe malaria using alanine metabolism as a measure. Alanine disposition and liver blood flow, assessed by indocyanine green (ICG) clearance, were measured simultaneously in 10 patients with falciparum malaria (six severe and four

  8. Alanine - Valine dynamics in pregnant rabbits | Emudianughe ...

    African Journals Online (AJOL)

    [15N]-alanine and [15N]–valine dynamics were studied in 29 -30 days pregnant New-Zealand rabbits. Over the experimental period, there was no detectable significant difference of mean ± SD of alanine concentrations within the sampling intervals in maternal, umbilical venous and arterial blood samples suggesting that ...

  9. Protection against hyperthermic cell killing by alanine

    International Nuclear Information System (INIS)

    Cunningham, A.; Henle, K.J.; Moss, A.J.; Nagle, W.A.

    1987-01-01

    Compounds capable of protecting cells against hyperthermia may provide new insights into potential mechanisms of thermotolerance and cellular heat death. The authors characterized heat protection by alanine and related compounds as a function of concentration, temperature and preincubation time. Alanine was added either to complete medium or to HBSS before hyperthermia. Maximal heat protection required 3 hr, 37 0 ; longer preincubation intervals resulted in lower levels of protection. Addition of alanine to medium after hyperthermia had no protective effect. Protection was concentration dependent with a 20- or 200-fold increase in cell survival after 40 min, 45 0 C at 60 mM in medium or in HBSS, respectively. Higher alanine concentrations up to 120mM did not significantly increase heat protection. A 45 0 -heat survival curve showed that 100mM alanine increased the D/sub q/ by approx. 12 min with little change in the D/sub o/. Hyperthermia of 1 hr at temperatures between 42 0 and 45 0 indicated that 100mM alanine shifted the isotoxic temperature by 0.5 Celsius degrees. Polymers of either L or D,L alanine and related compounds, like pyruvate, also protected cells against heat killing. These results indicate that heat protection by alanine shows characteristics that are not shared by polyhydroxy compounds

  10. X-Ray diffraction and scanning electron microscopy-energy dispersive spectroscopic analysis of ceramõmetal interface at different firing temperatures

    Directory of Open Access Journals (Sweden)

    Monika Saini

    2010-01-01

    Full Text Available Objective: Porcelain chipping from porcelain fused to metal restoration has been Achilles heel till date. There has been advent of newer ceramics in past but but none of them has been a panacea for Porcelain fracture. An optimal firing is thus essential for the clinical success of the porcelain-fused to metal restoration. The aim of the present study was to evaluate ceramo-metal interface at different firing temperature using XRD and SEM-EDS analysis. Clinical implication of the study was to predict the optimal firing temperature at which porcelain should be fused with metal in order to possibly prevent the occasional failure of the porcelain fused to metal restorations. Materials and Methods: To meet the above-mentioned goal, porcelain was fused to metal at different firing temperatures (930-990°C in vacuum. The microstructural observations of interface between porcelain and metal were evaluated using X-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. Results: Based on the experimental investigation of the interaction zone of porcelain fused to metal samples, it was observed that as the firing temperature was increased, the pores became less in number as well as the size of the pores decreased at the porcelain/metal interface upto 975°C but increased in size at 990°C. The least number of pores with least diameter were found in samples fired at 975°C. Several oxides like Cr 2 O 3 , NiO, and Al 2 O 3 and intermetallic compounds (CrSi 2 , AlNi 3 were also formed in the interaction zone. Conclusions : It is suggested that the presence of pores may trigger the crack propagation along the interface, causing the failure of the porcelain fused to metal restoration during masticatory action.

  11. Scanning electron microscopy (SEM) and X-ray dispersive spectrometry evaluation of direct laser metal sintering surface and human bone interface: a case series.

    Science.gov (United States)

    Mangano, Carlo; Piattelli, Adriano; Raspanti, Mario; Mangano, Francesco; Cassoni, Alessandra; Iezzi, Giovanna; Shibli, Jamil Awad

    2011-01-01

    Recent studies have shown that direct laser metal sintering (DLMS) produces structures with complex geometry and consequently that allow better osteoconductive properties. The aim of this patient report was to evaluate the early bone response to DLMS implant surface retrieved from human jaws. Four experimental DLMS implants were inserted in the posterior mandible of four patients during conventional dental implant surgery. After 8 weeks, the micro-implants and the surrounding tissue were removed and prepared for scanning electron microscopy (SEM) and histomorphometric analysis to evaluate the bone-implant interface. The SEM and EDX evaluations showed a newly formed tissue composed of calcium and phosphorus. The bone-to-implant contact presented a mean of 60.5 ± 11.6%. Within the limits of this patient report, data suggest that the DLMS surfaces presented a close contact with the human bone after a healing period of 8 weeks.

  12. Alanine EPR dosimetry of therapeutic irradiators

    International Nuclear Information System (INIS)

    Bugay, O.; Bartchuk, V.; Kolesnik, S.; Mazin, M.; Gaponenko, H.

    1999-01-01

    The high-dose alanine EPR dosimetry is a very precise method in the dose range 1-100 kGy. The system is used generally as the standard high-dose transfer dosimetry in many laboratories. This is comparatively expensive technique so it is important to use it as a more universal dosimetry system also in the middle and low dose ranges. The problems of the middle-dose alanine dosimetry are discussed and the solution of several problems is proposed. The alanine EPR dosimetry has been applied to the dose measurements of medical irradiators in the Kiev City Oncology Center. (author)

  13. Alanine increases blood pressure during hypotension

    Science.gov (United States)

    Conlay, L. A.; Maher, T. J.; Wurtman, R. J.

    1990-01-01

    The effect of L-alanine administration on blood pressure (BP) during haemorrhagic shock was investigated using anesthetized rats whose left carotid arteries were cannulated for BP measurement, blood removal, and drug administration. It was found that L-alanine, in doses of 10, 25, 50, 100, and 200 mg/kg, increased the systolic BP of hypotensive rats by 38 to 80 percent (while 100 mg/kg pyruvate increased BP by only 9.4 mmhg, not significantly different from saline). The results suggest that L-alanine might influence cardiovascular function.

  14. Scanning and transmission electron microscopy study of the microstructural changes occurring in aluminium matrix composites reinforced with SiC particles during casting and welding: interface reactions

    Science.gov (United States)

    Urena; Gomez De Salazar JM; Gil; Escalera; Baldonedo

    1999-11-01

    Processing of aluminium matrix composites (AMCs), especially those constituted by a reactive system such as Al-SiC, presents great difficulties which limit their potential applications. The interface reactivity between SiC and molten Al generates an aluminium carbide which degrades the composite properties. Scanning and transmission electron microscopes equipped with energy-dispersive X-ray spectroscopes are essential tools for determining the structure and chemistry of the Al-SiC interfaces in AMCs and changes occurring during casting and arc welding. In the present work, an aluminium-copper alloy (AA2014) reinforced with three different percentages of SiC particles was subjected to controlled remelting tests, at temperatures in the range 750-900 degrees C for 10 and 30 min. Arc welding tests using a tungsten intert gas with power inputs in the range 850-2000 W were also carried out. The results of these studies showed that during remelting there is preferential SiC particle consumption with formation of Al4C3 by interface reaction between the solid SiC particle and the molten aluminium matrix. The formation of Al4C3 by the same mechanism has also been detected in molten pools of arc welded composites. However, in this case there was formation of an almost continuous layer of Al4C3, which protects the particle against further consumption, and formation of aciculate aluminium carbide on the top weld. Both are formed by fusion and dissolution of the SiC in molten aluminium followed by reaction and precipitation of the Al4C3 during cooling.

  15. Electronic characterization of LaAlO{sub 3}-SrTiO{sub 3} interfaces by scanning tunneling spectroscopy; Elektronische Charakterisierung von LaAlO{sub 3}-SrTiO{sub 3}-Grenzflaechen mittels Rastertunnelspektroskopie

    Energy Technology Data Exchange (ETDEWEB)

    Breitschaft, Martin

    2010-10-22

    When LaAlO{sub 3} is epitaxially grown on TiO{sub 2}-terminated SrTiO{sub 3}, an electrically conducting interface is generated. In this respect, the physical properties of the interface differ substantially from those of both LaAlO{sub 3} and SrTiO{sub 3}, which are electrically insulating in bulk form. This dissertation looks into the question of the microscopic structure of the conducting two-dimensional interface electron system. Comparing the electronic density of states of LaAlO{sub 3}-SrTiO{sub 3} interfaces measured by scanning tunneling spectroscopy with results of density functional theory, the interface electron system is found to be substantially coined by the hosting transition metal lattices. The comparison yields a detailed picture of the microscopic structure of the interface electron system. (orig.)

  16. Selection of D-Alanine-Tolerant Rice Cells

    OpenAIRE

    Hisashi, Manabe; Koji, Ohira; Aizu Junior College of Fukushima Prefecture; Department of Agricultural Chemistry, Faculty of Agriculture, Tohoku University

    1984-01-01

    By repeating subculture of rice cells (parent cells) in a D-alanine containing medium, we could select rice cells which grew well in the D-alanine medium. The D-alanine-tolerant cells absorbed a fairly small amount of D-alanine from the medium and did not accumulate much D-alanine in the cells. Aggregation of D-alanine-tolerant cells was greater than that of parent cells. D-Alanine metabolism of D-alanine.-tolerant cells did not increase in comparison with parent cells.

  17. Implementation of an alanine dosimetry service

    International Nuclear Information System (INIS)

    Gago Arias, A.; Nunez Pelaez, N.; Peteiro Vilaseco, E.; Gomez Rodriguez, F.; Gonzalez Castano, D. M.

    2011-01-01

    This work facing the implementation of an alanine dosimetry service, linked to the installation of Co 6 0 Radio physics Laboratory (LP) and Paramagnetic Resonance Service of the University of Santiago de Compostela (USC).

  18. EPR of alanine irradiated by neutrons

    International Nuclear Information System (INIS)

    Pivovarov, S.P.; Seredavina, T.A.; Zhdanov, S.V.; Mul'gin, S.I.; Zhakparov, R.K.

    2001-01-01

    In the work the first results of EPR studies of alanine, irradiated with diverse doses at neutron cyclotron generator different conditions and on the critical reactor stand are presented. A dose linearity dependence of EPR signal is observing, the methods of γ-background contribution separation are discussed. Obtain results is giving the basis to recommendation of alanine as an effective detector irradiation. However it is demanded the farther study on clarification of radiation sensitivity value dependence on the neutron energy spectrum form

  19. Solved? The reductive radiation chemistry of alanine.

    Science.gov (United States)

    Pauwels, Ewald; De Cooman, Hendrik; Waroquier, Michel; Hole, Eli O; Sagstuen, Einar

    2014-02-14

    The structural changes throughout the entire reductive radiation-induced pathway of l-α-alanine are solved on an atomistic level with the aid of periodic DFT and nudged elastic band (NEB) simulations. This yields unprecedented information on the conformational changes taking place, including the protonation state of the carboxyl group in the "unstable" and "stable" alanine radicals and the internal transformation converting these two radical variants at temperatures above 220 K. The structures of all stable radicals were verified by calculating EPR properties and comparing those with experimental data. The variation of the energy throughout the full radiochemical process provides crucial insight into the reason why these structural changes and rearrangements occur. Starting from electron capture, the excess electron quickly localizes on the carbon of a carboxyl group, which pyramidalizes and receives a proton from the amino group of a neighboring alanine molecule, forming a first stable radical species (up to 150 K). In the temperature interval 150-220 K, this radical deaminates and deprotonates at the carboxyl group, the detached amino group undergoes inversion and its methyl group sustains an internal rotation. This yields the so-called "unstable alanine radical". Above 220 K, triggered by the attachment of an additional proton on the detached amino group, the radical then undergoes an internal rotation in the reverse direction, giving rise to the "stable alanine radical", which is the final stage in the reductive radiation-induced decay of alanine.

  20. Functional Characterization of Alanine Racemase from Schizosaccharomyces pombe: a Eucaryotic Counterpart to Bacterial Alanine Racemase

    OpenAIRE

    Uo, Takuma; Yoshimura, Tohru; Tanaka, Naotaka; Takegawa, Kaoru; Esaki, Nobuyoshi

    2001-01-01

    Schizosaccharomyces pombe has an open reading frame, which we named alr1+, encoding a putative protein similar to bacterial alanine racemase. We cloned the alr1+ gene in Escherichia coli and purified the gene product (Alr1p), with an Mr of 41,590, to homogeneity. Alr1p contains pyridoxal 5′-phosphate as a coenzyme and catalyzes the racemization of alanine with apparent Km and Vmax values as follows: for l-alanine, 5.0 mM and 670 μmol/min/mg, respectively, and for d-alanine, 2.4 mM and 350 μmo...

  1. Experiences with alanine dosimetry in afterloading brachytherapy

    International Nuclear Information System (INIS)

    Eberhardt, H.-J.; Gohs, U.

    1996-01-01

    At the present, the most commonly used dosimetry for radiotherapy applications are ionisation chambers and thermoluminescent dosimeters (TLD). However, there are some undesirable characteristics of these dosimetry systems, such as large detection volume (ionisation chamber) as well as fading of the radiation induced signal with time and destructive readout (TLG). The present study is an investigation into the use of the alanine/ESR dosimetry in fractionated afterloading brachytherapy during the whole radiotherapy course. There are some qualities which make alanine dosimetry attractive. These are the linear energy response, low fading under standard conditions, and the nondestructive readout. Thus the alanine dosimetry makes possible cumulative dose measurements during the radiotherapy course and an archival storage. By ionizing radiation (gamma, e, n, p, charged particles) free radicals (unpaired electrons) are produced in the amino acid alanine. The continuous wave electron spin resonance (ESR) spectroscopy is used to determine the number of free radicals, which is proportional to the absorbed dose and the alanine content of the dosimeter. The ESR measurements were made at room temperature using a Bruker EPR analyzer EMS-104. The dosimeters used in the test are alanine pellets (23.72 mg weight, 4.9 mm diameter, 1 mm height) as well as flexible alanine film dosimeters (thickness about 500 μm). The dosimeters consist of a blend of L-alpha-alanine and a binder. The alanine content of the pellets and the film dosimeters is about 88 % and 50 % by weight, respectively. The dosimeters for the calculation of the dose-effect-relationship were irradiated at the Physical-Technical Bundesanstalt in Braunschweig by a standard 60Co source. The maximum deviation from the calculated linear function is about 0.12 Gy in the dose range up to 80 Gy. The goal of medical applications was the superficial dose measurement in afterloading brachytherapy during the radiotherapy course in

  2. 21 CFR 172.540 - DL-Alanine.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true DL-Alanine. 172.540 Section 172.540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Agents and Related Substances § 172.540 DL-Alanine. DL-Alanine (a racemic mixture of D- and L-alanine...

  3. Knockout of the alanine racemase gene in Aeromonas hydrophila HBNUAh01 results in cell wall damage and enhanced membrane permeability.

    Science.gov (United States)

    Liu, Dong; Zhang, Lu; Xue, Wen; Wang, Yaping; Ju, Jiansong; Zhao, Baohua

    2015-07-01

    This study focused on the alanine racemase gene (alr-2), which is involved in the synthesis of d-alanine that forms the backbone of the cell wall. A stable alr-2 knockout mutant of Aeromonas hydrophila HBNUAh01 was constructed. When the mutant was supplemented with d-alanine, growth was unaffected; deprivation of d-alanine caused the growth arrest of the starved mutant cells, but not cell lysis. No alanine racemase activity was detected in the culture of the mutant. Additionally, a membrane permeability assay showed increasing damage to the cell wall during d-alanine starvation. No such damage was observed in the wild type during culture. Scanning and transmission electron microscopy analyses revealed deficiencies of the cell envelope and perforation of the cell wall. Leakage of UV-absorbing substances from the mutants was also observed. Thus, the partial viability of the mutants and their independence of d-alanine for growth indicated that inactivation of alr-2 does not impose an auxotrophic requirement for d-alanine. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. Effect of Exogenous _D-Alanine on _D-Alanyl-_D-alanine Content in Leaf Blades of Oryza australiensis Domin

    OpenAIRE

    Hisashi, Manabe; Aizu Junior College of Fukushima Prefecture

    1986-01-01

    In seedlings of Oryza australiensis Domin (W0008), most of the D-alanyl-D-alanine was distributed in the leaf blades. In excised leaf blades of W0008, exogenous D-alanine was incorporated into D-alanyl-D-alanine irrespective of the light condition as in Sasanishiki. With cultivation in D-alanine medium for several days, the D-alanyl-D-alanine content in W0008 leaf blades was found to increase, but no other D-alanine-containing dipeptides such as D-alanylglycine or D-alanyl-L-alanine were dete...

  5. Scanning Electron Microscope (SEM Evaluation of the Interface between a Nanostructured Calcium-Incorporated Dental Implant Surface and the Human Bone

    Directory of Open Access Journals (Sweden)

    Francesco Mangano

    2017-12-01

    Full Text Available Purpose. The aim of this scanning electron microscope (SEM study was to investigate the interface between the bone and a novel nanostructured calcium-incorporated dental implant surface in humans. Methods. A dental implant (Anyridge®, Megagen Implant Co., Gyeongbuk, South Korea with a nanostructured calcium-incorporated surface (Xpeed®, Megagen Implant Co., Gyeongbuk, South Korea, which had been placed a month earlier in a fully healed site of the posterior maxilla (#14 of a 48-year-old female patient, and which had been subjected to immediate functional loading, was removed after a traumatic injury. Despite the violent trauma that caused mobilization of the fixture, its surface appeared to be covered by a firmly attached, intact tissue; therefore, it was subjected to SEM examination. The implant surface of an unused nanostructured calcium-incorporated implant was also observed under SEM, as control. Results. The surface of the unused implant showed a highly-structured texture, carved by irregular, multi-scale hollows reminiscent of a fractal structure. It appeared perfectly clean and devoid of any contamination. The human specimen showed trabecular bone firmly anchored to the implant surface, bridging the screw threads and filling the spaces among them. Conclusions. Within the limits of this human histological report, the sample analyzed showed that the nanostructured calcium-incorporated surface was covered by new bone, one month after placement in the posterior maxilla, under an immediate functional loading protocol.

  6. A molecular receptor selective for zwitterionic alanine.

    Science.gov (United States)

    Rubio, Omayra H; Taouil, Rachid; Muñiz, Francisco M; Monleón, Laura M; Simón, Luis; Sanz, Francisca; Morán, Joaquín R

    2017-01-04

    A molecular receptor has been synthesized joining an aza-crown ether with a chiral chromane which mimics the oxyanion hole of the enzymes. With this receptor an apolar host-guest complex with zwitterionic alanine has been achieved through the formation of up to seven H-bonds. This complex allows the extraction of aqueous alanine to a chloroform phase, while other natural amino acids are poorly extracted or are not extracted at all. Due to the chiral nature of the receptor, enantioselective extraction from the aqueous alanine solution to a chloroform phase takes place. X-Ray analysis combined with anisotropic effects, NOE and CD studies revealed the absolute configuration of both strong and weak complexes. Modelling studies also support the proposed structures. The presence of an oxyanion-hole motif in this structure was corroborated by X-ray diffraction studies.

  7. A study of the irradiation temperature coefficient for L-alanine and DL-alanine dosemeters

    International Nuclear Information System (INIS)

    Desrosiers, M. F.; Lin, M.; Cooper, S. L.; Cui, Y.; Chen, K.

    2006-01-01

    Alanine dosimetry is now well established both as a reference and routine dosemeter for industrial irradiation processing. Accurate dosimetry under the relatively harsh conditions of industrial processing requires a characterisation of the parameters that influence the dosemeter response. The temperature of the dosemeter during irradiation is a difficult quantity to measure so that the accuracy of the temperature coefficient that governs the dosemeter response becomes a critical factor. Numerous publications have reported temperature coefficients for several types of alanine dosemeters. The observed differences in the measured values were commonly attributed to the differences in the polymer binder or the experimental design of the measurement. However, the data demonstrated a consistent difference in the temperature coefficients between L-alanine and DL-alanine. Since there were no commonalities in the dosemeter composition or the measurement methods applied, a clear conclusion is not possible. To resolve this issue, the two isomeric forms of alanine dosemeters were prepared and irradiated in an identical manner. The results indicated that the DL-alanine temperature coefficient is more than 50% higher than the L-alanine temperature coefficient. (authors)

  8. Potential energy surface of alanine polypeptide chains

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Yakubovich, Alexander V.; Solov'yov, Andrey V.

    2006-01-01

    The multidimensional potential energy surfaces of the peptide chains consisting of three and six alanine (Ala) residues have been studied with respect to the degrees of freedom related to the twist of these molecules relative to the peptide backbone (these degrees of freedom are responsible...

  9. Dosimetry auditing procedure with alanine dosimeters for light ion beam therapy

    DEFF Research Database (Denmark)

    Ableitinger, Alexander; Vatnitsky, Stanislav; Herrmann, Rochus

    2013-01-01

    Background and purpose In the next few years the number of facilities providing ion beam therapy with scanning beams will increase. An auditing process based on an end-to-end test (including CT imaging, planning and dose delivery) could help new ion therapy centres to validate their entire logistic...... of the biological dose is out of scope of the current work. Materials and methods The audit procedure was based on a homogeneous phantom that mimics the dimension of a head (20 × 20 × 21 cm3). The phantom can be loaded either with an ionisation chamber or 20 alanine dosimeters plus 2 radiochromic EBT films. Dose...... fluence in the alanine detector. A pilot run was performed with protons and carbon ions at the Heidelberg Ion Therapy facility (HIT). Results The mean difference of the absolute physical dose measured with the alanine dosimeters compared with the expected dose from the treatment planning system was −2...

  10. Evidence for Time-Reversal Symmetry Breaking of the Superconducting State near Twin-Boundary Interfaces in FeSe Revealed by Scanning Tunneling Spectroscopy

    Directory of Open Access Journals (Sweden)

    T. Watashige

    2015-08-01

    Full Text Available Junctions and interfaces consisting of unconventional superconductors provide an excellent experimental playground to study exotic phenomena related to the phase of the order parameter. Not only does the complex structure of unconventional order parameters have an impact on the Josephson effects, but it also may profoundly alter the quasiparticle excitation spectrum near a junction. Here, by using spectroscopic-imaging scanning tunneling microscopy, we visualize the spatial evolution of the LDOS near twin boundaries (TBs of the nodal superconductor FeSe. The π/2 rotation of the crystallographic orientation across the TB twists the structure of the unconventional order parameter, which may, in principle, bring about a zero-energy LDOS peak at the TB. The LDOS at the TB observed in our study, in contrast, does not exhibit any signature of a zero-energy peak, and an apparent gap amplitude remains finite all the way across the TB. The low-energy quasiparticle excitations associated with the gap nodes are affected by the TB over a distance more than an order of magnitude larger than the coherence length ξ_{ab}. The modification of the low-energy states is even more prominent in the region between two neighboring TBs separated by a distance ≈7ξ_{ab}. In this region, the spectral weight near the Fermi level (≈±0.2  meV due to the nodal quasiparticle spectrum is almost completely removed. These behaviors suggest that the TB induces a fully gapped state, invoking a possible twist of the order parameter structure, which breaks time-reversal symmetry.

  11. Absorbed dose determination in kilovoltage X-ray synchrotron radiation using alanine dosimeters.

    Science.gov (United States)

    Butler, D J; Lye, J E; Wright, T E; Crossley, D; Sharpe, P H G; Stevenson, A W; Livingstone, J; Crosbie, J C

    2016-12-01

    Alanine dosimeters from the National Physical Laboratory (NPL) in the UK were irradiated using kilovoltage synchrotron radiation at the imaging and medical beam line (IMBL) at the Australian Synchrotron. A 20 × 20 mm 2 area was irradiated by scanning the phantom containing the alanine through the 1 mm × 20 mm beam at a constant velocity. The polychromatic beam had an average energy of 95 keV and nominal absorbed dose to water rate of 250 Gy/s. The absorbed dose to water in the solid water phantom was first determined using a PTW Model 31014 PinPoint ionization chamber traceable to a graphite calorimeter. The alanine was read out at NPL using correction factors determined for 60 Co, traceable to NPL standards, and a published energy correction was applied to correct for the effect of the synchrotron beam quality. The ratio of the doses determined by alanine at NPL and those determined at the synchrotron was 0.975 (standard uncertainty 0.042) when alanine energy correction factors published by Waldeland et al. (Waldeland E, Hole E O, Sagstuen E and Malinen E, Med. Phys. 2010, 37, 3569) were used, and 0.996 (standard uncertainty 0.031) when factors by Anton et al. (Anton M, Büermann L., Phys Med Biol. 2015 60 6113-29) were used. The results provide additional verification of the IMBL dosimetry.

  12. Simultaneous determination of F-beta-alanine and beta-alanine in plasma and urine with dual-column reversed-phase high-performance liquid chromatography

    NARCIS (Netherlands)

    van Kuilenburg, A. B.; Stroomer, A. E.; Peters, G. J.; van Gennip, A. H.

    2001-01-01

    F-beta-Alanine and beta-alanine were detected in plasma and urine samples with fluorescence detection of orthophthaldialdehyde derivatives of F-beta-alanine and beta-alanine after separation with dual-column reversed-phase HPLC. The detection limits of F-beta-alanine and beta-alanine in the HPLC

  13. Structure of poly (. beta. -alanine) polymerized in the solid state. Koso jugo shita. beta. -alanine no kozo

    Energy Technology Data Exchange (ETDEWEB)

    Sakabe, Hiroshi; Nakamura, Hiroyoshi; Kimura, Hirokazu; Konishi, Takashi [Kyoto Inst. of Tech., Kyoto (Japan). Faculty of Textile Science

    1989-12-05

    The structure of poly({beta}-alanine) polymerized in the solid state was studied. This polymerization was carried out on a single crystal of {beta}-alanine at 170 centigrade for 40 h in an evacuated tube. The crystal structure of the polymer was assigned to I-type crystal of Nylon 3. The polymer chains were oriented vertical to the crystal side and different to monomer crystal orientation. This may be caused by the molecular layer slipping along the cleavage plane of monomer crystal. A scanning electron microscope(SEM) showed the band structure of hundreds nm width of same orientation, but X ray showed only unoriented rings, so that they are estimated to be the structure of fine fibril like assembly or necklace like continuous chain structure of grains. Near the surface, whiskers which were thought to be oligomer of low degree of polymerization, were observed. The SEM of end view of the etched surface did not show the laminated structure but showed the network structure of about 1 mu-m which is thought to be fibril precursor. 12 refs., 10 figs.

  14. Secretion of d-alanine by Escherichia coli.

    Science.gov (United States)

    Katsube, Satoshi; Sato, Kazuki; Ando, Tasuke; Isogai, Emiko; Yoneyama, Hiroshi

    2016-07-01

    Escherichia coli has an l-alanine export system that protects the cells from toxic accumulation of intracellular l-alanine in the presence of l-alanyl-l-alanine (l-Ala-l-Ala). When a DadA-deficient strain was incubated with 6.0 mM l-Ala-l-Ala, we detected l-alanine and d-alanine using high-performance liquid chromatography (HPLC) analysis at a level of 7.0 mM and 3.0 mM, respectively, after 48 h incubation. Treatment of the culture supernatant with d-amino acid oxidase resulted in the disappearance of a signal corresponding to d-alanine. Additionally, the culture supernatant enabled a d-alanine auxotroph to grow without d-alanine supplementation, confirming that the signal detected by HPLC was authentic d-alanine. Upon introduction of an expression vector harbouring the alanine racemase genes, alr or dadX, the extracellular level of d-alanine increased to 11.5 mM and 8.5 mM, respectively, under similar conditions, suggesting that increased metabolic flow from l-alanine to d-alanine enhanced d-alanine secretion. When high-density DadA-deficient cells preloaded with l-Ala-l-Ala were treated with 20 µM carbonyl cyanide m-chlorophenyl hydrazone (CCCP), secretion of both l-alanine and d-alanine was enhanced ~twofold compared with that in cells without CCCP treatment. In contrast, the ATPase inhibitor dicyclohexylcarbodiimide did not exert such an effect on the l-alanine and d-alanine secretion. Furthermore, inverted membrane vesicles prepared from DadA-deficient cells lacking the l-alanine exporter AlaE accumulated [3H]D-alanine in an energy-dependent manner. This energy-dependent accumulation of [3H]D-alanine was strongly inhibited by CCCP. These results indicate that E. coli has a transport system(s) that exports d-alanine and that this function is most likely modulated by proton electrochemical potential.

  15. Alanine Aminotransferase, ?-Glutamyltransferase, and Incident Diabetes

    OpenAIRE

    Fraser, Abigail; Harris, Ross; Sattar, Naveed; Ebrahim, Shah; Davey Smith, George; Lawlor, Debbie A.

    2009-01-01

    OBJECTIVE: To estimate and compare associations of alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) with incident diabetes. RESEARCH DESIGN AND METHODS: ALT and GGT were studied as determinants of diabetes in the British Women's Heart and Health Study, a cohort of 4,286 women 60-79 years old (median follow-up 7.3 years). A systematic review and a meta-analysis of 21 prospective, population-based studies of ultrasonography, which diagnosed nonalcoholic fatty liver disease (NA...

  16. IAEA reference dosimeter: Alanine-ESR

    International Nuclear Information System (INIS)

    Mehta, K.; Girzikowsky, R.

    1999-01-01

    Since 1985, the IAEA has been using alanine-ESR as a transfer dosimeter for its dose quality audit service, namely the International Dose Assurance Service. The alanine dosimeters are rod-type containing 70 wt% DL--α-alanine and 30 wt% polystyrene. We have two self-shielded gamma facilities for the calibration of the dosimetry system, where the temperature within the irradiation chamber can be controlled by a specially designed unit. A 4th order polynomial is fitted to the 16 data points in the dose range of 100 Gy to 50 kGy. The measured value of the irradiation temperature coefficient at two dose values (15 and 45 kGy) is 0.23 %/deg. C. Also, the ESR-response was followed for several dosimeters for about 8 months to study the post-irradiation effect. A value of 0.008 %/day was observed for the fading of the response for two dose values (15 and 45 kGy) and three irradiation temperatures (15, 27 and 40 deg. C). The effect of the analysis temperature on the ESR response was also studied. The combined relative uncertainty for the IAEA alanine-ESR dosimetry system is 1.5% (k=1). This includes that transferred from the primary laboratory for the dose rate measurements of the gamma facilities, dosimetry system calibration uncertainties, batch variability and uncertainty in the curve fitting procedure. This value however does not include the contribution due to the irradiation temperature correction which is applied when it differs from that during calibration; this component being specific for each dose measurement. (author)

  17. Green reduction of graphene oxide using alanine

    International Nuclear Information System (INIS)

    Wang, Jiabin; Salihi, Elif Caliskan; Šiller, Lidija

    2017-01-01

    There remains a real need for the easy, eco-friendly and scalable preparation method of graphene due to various potential applications. Chemical reduction is the most versatile method for the large scale production of graphene. Here we report the operating conditions for a one-step, economical and green synthesis method for the reduction of graphene oxide using a biomolecule (alanine). Graphene oxide was produced by the oxidation and exfoliation of natural graphite flake with strong oxidants using Hummers method (Hummers and Offeman, 1958), but the method was revised in our laboratory to set up a safe and environmentally friendly route. The reduction of graphene oxide was investigated using alanine at various operating conditions in order to set up optimum conditions (treatment time, temperature and concentration of the reagent). Samples have been characterized by using UV–Visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction analysis. - Highlights: • An environmentally friendly route was reported for the chemical reduction of graphene oxide (GO). • Alanine could reduce GO to rGO (reduced graphene oxide) without using any stabilizer or alcaline medium. • Characterization studies confirmed the successful deoxygenation of GO.

  18. Green reduction of graphene oxide using alanine

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiabin [Newcastle University, School of Chemical Engineering and Advanced Materials, Newcastle upon Tyne NE1 7RU (United Kingdom); Salihi, Elif Caliskan, E-mail: caliskanelif@gmail.com [Newcastle University, School of Chemical Engineering and Advanced Materials, Newcastle upon Tyne NE1 7RU (United Kingdom); Marmara University, Faculty of Pharmacy, Department of Basic Pharmaceutical Sciences, 34668 Istanbul (Turkey); Šiller, Lidija [Newcastle University, School of Chemical Engineering and Advanced Materials, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2017-03-01

    There remains a real need for the easy, eco-friendly and scalable preparation method of graphene due to various potential applications. Chemical reduction is the most versatile method for the large scale production of graphene. Here we report the operating conditions for a one-step, economical and green synthesis method for the reduction of graphene oxide using a biomolecule (alanine). Graphene oxide was produced by the oxidation and exfoliation of natural graphite flake with strong oxidants using Hummers method (Hummers and Offeman, 1958), but the method was revised in our laboratory to set up a safe and environmentally friendly route. The reduction of graphene oxide was investigated using alanine at various operating conditions in order to set up optimum conditions (treatment time, temperature and concentration of the reagent). Samples have been characterized by using UV–Visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction analysis. - Highlights: • An environmentally friendly route was reported for the chemical reduction of graphene oxide (GO). • Alanine could reduce GO to rGO (reduced graphene oxide) without using any stabilizer or alcaline medium. • Characterization studies confirmed the successful deoxygenation of GO.

  19. Earthworms accumulate alanine in response to drought.

    Science.gov (United States)

    Holmstrup, Martin; Slotsbo, Stine; Henriksen, Per G; Bayley, Mark

    2016-09-01

    Earthworms have ecologically significant functions in tropical and temperate ecosystems and it is therefore important to understand how these animals survive during drought. In order to explore the physiological responses to dry conditions, we simulated a natural drought incident in a laboratory trial exposing worms in slowly drying soil for about one month, and then analyzed the whole-body contents of free amino acids (FAAs). We investigated three species forming estivation chambers when soils dry out (Aporrectodea tuberculata, Aporrectodea icterica and Aporrectodea longa) and one species that does not estivate during drought (Lumbricus rubellus). Worms subjected to drought conditions (alanine that was significantly upregulated in all tested species. Alanine was the most important FAA reaching 250-650μmolg(-1) dry weight in dehydrated Aporrectodea species and 300μmolg(-1) dry weight in L. rubellus. Proline was only weakly upregulated in some species as were a few other FAAs. Species forming estivation chambers (Aporrectodea spp.) did not show a better ability to conserve body water than the non-estivating species (L. rubellus) at the same drought level. These results suggest that the accumulation of alanine is an important adaptive trait in drought tolerance of earthworms in general. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Characteristics and application of alanine dosimeter 'Aminogray'

    International Nuclear Information System (INIS)

    Kashiwazaki, Shigeru; Matsuyama, Shigeki; Hatta, Toshimasa; Yagyu, Hideki; Kojima, Takuji; Tanaka, Ryuichi; Morita, Yohsuke.

    1988-01-01

    Recently, accompanying the progress of nuclear power generation and space development, the evaluation of reliability for the materials and parts used under irradiation has become important. For the evaluation of reliability, the accurate grasp of radiation dose is the prerequisite. In some case, the measurement of cumulative dose in a long period in an actual environment becomes necessary. In this paper, the characteristics and application of a new dosimeter element 'Aminogray' which is suitable to the above requirement are reported. Aminogray is rodshape element made by forming alanine, a kind of amino acid, using a binder polymer, and the alanine content is 70 wt.%, and the polymer is polystyrene. An element of 3 mm diameter and 30 mm length is enclosed in a polystyrene cylinder of 4 mm thickness. This thickness was determined by considering the electronic equilibrium condition in Co-60 gamma-ray irradiation. The principle of the measurement is to determine a dose by measuring the amount of free radicals produced in alanine by radiation using ESR method. The free radicals are extremely stable, and exist for a long period, and the amount of radical production is proportional to absorbed dose. The development, characteristics and application of Aminogray are reported. (K.I.)

  1. Alanine metabolism in pyridoxine-depleted rat liver

    International Nuclear Information System (INIS)

    Okada, Mitsuko; Abe, Midori

    1976-01-01

    Alanine metabolism in normal and pyridoxine-deficient rats was studied in vivo and in vitro. Incorporation of 14 C-alanine into various liver components was determined and no difference was shown between normal and deficient animals in the incorporation into liver homogenates, lipid, protein and plasma glucose. Using the liver slice system, gluconeogenic activity from alanine or pyruvate was 40% lower in deficient rats compared with the activity of normal rats. However, inhibition was completely removed by the addition of 2-oxoglutarate to alanine. Penicillamine did not affect glucose formation from alanine in the liver slice. (auth.)

  2. Highly Efficient Fumed Silica Nanoparticles for Peptide Bond Formation: Converting Alanine to Alanine Anhydride.

    Science.gov (United States)

    Guo, Chengchen; Jordan, Jacob S; Yarger, Jeffery L; Holland, Gregory P

    2017-05-24

    In this work, thermal condensation of alanine adsorbed on fumed silica nanoparticles is investigated using thermal analysis and multiple spectroscopic techniques, including infrared (IR), Raman, and nuclear magnetic resonance (NMR) spectroscopies. Thermal analysis shows that adsorbed alanine can undergo thermal condensation, forming peptide bonds within a short time period and at a lower temperature (∼170 °C) on fumed silica nanoparticle surfaces than that in bulk (∼210 °C). Spectroscopic results further show that alanine is converted to alanine anhydride with a yield of 98.8% during thermal condensation. After comparing peptide formation on solution-derived colloidal silica nanoparticles, it is found that fumed silica nanoparticles show much better efficiency and selectivity than solution-derived colloidal silica nanoparticles for synthesizing alanine anhydride. Furthermore, Raman spectroscopy provides evidence that the high efficiency for fumed silica nanoparticles is likely related to their unique surface features: the intrinsic high population of strained ring structures present at the surface. This work indicates the great potential of fumed silica nanoparticles in synthesizing peptides with high efficiency and selectivity.

  3. Imaging analysis of direct alanine uptake by rice seedlings

    International Nuclear Information System (INIS)

    Nihei, Naoto; Masuda, Sayaka; Rai, Hiroki; Nakanishi, Tomoko M.

    2008-01-01

    We presented alanine, a kind of amino acids, uptake by a rice seedling to study the basic mechanism of the organic fertilizer effectiveness in organic farming. The rice grown in the culture solution containing alanine as a nitrogen source absorbed alanine approximately two times faster than that grown with NH 4 + from analysis of 14 C-alanine images by Imaging Plate method. It was suggested that the active transport ability of the rice seeding was induced in roots by existence of alanine in the rhizosphere. The alanine uptake images of the rice roots were acquired every 5 minutes successively by the real-time autoradiography system we developed. The analysis of the successive images showed that alanine uptake was not uniform throughout the root but especially active at the root tip. (author)

  4. Alanine flux in obese and healthy humans as evaluated by 15N- and 2H3-labeled alanines

    International Nuclear Information System (INIS)

    Hoffer, L.J.; Yang, R.D.; Matthews, D.E.; Bistrian, B.R.; Bier, D.M.; Young, V.R.

    1988-01-01

    Estimates of plasma alanine flux as measured in humans using L-[ 15 N]-alanine or L-[3,3,3- 2 H 3 ]alanine were compared by simultaneous intravenous infusion of both tracers. Plasma isotope enrichments were measured by chemical ionization gas chromatography-mass spectrometry. In 16 obese women before and during a hypocaloric diet and in 4 normal men in the postabsorptive and fed states, the fluxes were highly correlated (r2 = 0.93) although plasma alanine flux with the 2 H tracer was two to three times greater than that obtained with [ 15 N]alanine. The fluxes decreased with the hypocaloric diet in obese subjects and increased during the fed state in healthy adults. Thus, although the estimates of alanine flux differed according to the tracer used, both appear to give equivalent information about changes in alanine kinetics induced by the nutritional conditions examined

  5. Comparison of alanine dosimeters using silicone as their binder to a commercial, polystyrene-bound, alanine dosimeter

    International Nuclear Information System (INIS)

    Galindo, S.; Urena-Nunez, F.

    1997-01-01

    The feasibility of practical boron-containing alanine ESR dosimeters for gamma-neutron mixed field irradiation dosimeters depends in part on whether the γ response characteristics of these silicone-bound dosimeters are comparable to those of a commercially available dosimeter that has been used by the International Atomic Energy Agency (International Dose Assurance Service) as a transfer reference dosimeter. This work presents the results of the comparison of 3 batches of silicone-bound alanine dosimeters. The first batch consists of a mixture of alanine and boric acid; the second, alanine and borax; and the last contains only alanine. Results indicate that γ response characteristics of the silicone-bound samples are comparable to those of the commercial, polystyrene-bound, alanine dosimeter and that silicone has a strong potential as a binding substance for alanine ESR dosimetry. (Author)

  6. Synthesis, characterization, and biocompatible properties of alanine-grafted chitosan copolymers.

    Science.gov (United States)

    Park, Gyu Han; Kang, Min-Sil; Knowles, Jonathan C; Gong, Myoung-Seon

    2016-04-01

    In order to overcome major problems regarding the lack of affinity to solvents and limited reactivity of the free amines of chitosan, introduction of appropriate spacer arms having terminal amine function is considered of interest. L-Alanine-N-carboxyanhydride was grafted onto chitosan via anionic ring-opening polymerization. The chemical and structural characterizations of L-alanine-grafted chitosan (Ala-g-Cts) were confirmed through Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy ((1)H NMR). In addition, the viscoelastic properties of Ala-g-Cts were examined by means of a rotational viscometer, and thermal analysis was carried out with a thermogravimetric analyzer and differential scanning calorimetry. Morphological changes in the chitosan L-alanine moiety were determined by x-ray diffraction. To determine the feasibility of using these films as biomedical materials, we investigated the effects of their L-alanine content on physical and mechanical properties. The biodegradation results of crosslinked Ala-g-Cts films were evaluated in phosphate-buffered solution containing lysozyme at 37℃. Proliferation of MC3T3-E1 cells on crosslinked Ala-g-Cts films was also investigated with use of the CCK-8 assay. © The Author(s) 2016.

  7. Determination of the dose of traffic in HDR brachytherapy with ALANINE/R PE technique

    International Nuclear Information System (INIS)

    Guzman Calcina, C. S.; Chen, F.; Almeida, A. de; Baffa, O.

    2001-01-01

    It determines, experimentally, the dose of traffic in brachytherapy for High Dose Rate (HDR), using for the first-time the Electronic Paramagnetic Resonance (EPR) technique with alanine detectors. The value obtained is the published next to obtained using lithium fluoride thermoluminescent dosimeters [es

  8. Crystallization and preliminary crystallographic analysis of d-alanine-d-alanine ligase from Streptococcus mutans

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yong-Zhi; Sheng, Yu [Institute for Nanobiomedical Technology and Membrane Biology, West China Hospital, Sichuan University, Chengdu 610065, Sichuan (China); Li, Lan-Fen [National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871 (China); Tang, De-Wei [Institute for Nanobiomedical Technology and Membrane Biology, West China Hospital, Sichuan University, Chengdu 610065, Sichuan (China); Liu, Xiang-Yu [National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871 (China); Zhao, Xiaojun, E-mail: zhaoxj@scu.edu.cn [Institute for Nanobiomedical Technology and Membrane Biology, West China Hospital, Sichuan University, Chengdu 610065, Sichuan (China); Liang, Yu-He, E-mail: zhaoxj@scu.edu.cn; Su, Xiao-Dong [National Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871 (China); Institute for Nanobiomedical Technology and Membrane Biology, West China Hospital, Sichuan University, Chengdu 610065, Sichuan (China)

    2007-09-01

    A potential target for antibiotic drug design, d-alanine-d-alanine ligase from S. mutans, was expressed in E. coli, purified and crystallized. Diffraction data were collected to 2.4 Å resolution. d-Alanine-d-alanine ligase is encoded by the gene ddl (SMU-599) in Streptococcus mutans. This ligase plays a very important role in cell-wall biosynthesis and may be a potential target for drug design. To study the structure and function of this ligase, the gene ddl was amplified from S. mutans genomic DNA and cloned into the expression vector pET28a. The protein was expressed in soluble form in Escherichia coli strain BL21 (DE3). Homogeneous protein was obtained using a two-step procedure consisting of Ni{sup 2+}-chelating and size-exclusion chromatography. Purified protein was crystallized and the cube-shaped crystal diffracted to 2.4 Å. The crystal belongs to space group P3{sub 1}21 or P3{sub 2}21, with unit-cell parameters a = b = 79.50, c = 108.97 Å. There is one molecule per asymmetric unit.

  9. Crystallization and preliminary crystallographic analysis of d-alanine-d-alanine ligase from Streptococcus mutans

    International Nuclear Information System (INIS)

    Lu, Yong-Zhi; Sheng, Yu; Li, Lan-Fen; Tang, De-Wei; Liu, Xiang-Yu; Zhao, Xiaojun; Liang, Yu-He; Su, Xiao-Dong

    2007-01-01

    A potential target for antibiotic drug design, d-alanine-d-alanine ligase from S. mutans, was expressed in E. coli, purified and crystallized. Diffraction data were collected to 2.4 Å resolution. d-Alanine-d-alanine ligase is encoded by the gene ddl (SMU-599) in Streptococcus mutans. This ligase plays a very important role in cell-wall biosynthesis and may be a potential target for drug design. To study the structure and function of this ligase, the gene ddl was amplified from S. mutans genomic DNA and cloned into the expression vector pET28a. The protein was expressed in soluble form in Escherichia coli strain BL21 (DE3). Homogeneous protein was obtained using a two-step procedure consisting of Ni 2+ -chelating and size-exclusion chromatography. Purified protein was crystallized and the cube-shaped crystal diffracted to 2.4 Å. The crystal belongs to space group P3 1 21 or P3 2 21, with unit-cell parameters a = b = 79.50, c = 108.97 Å. There is one molecule per asymmetric unit

  10. Racemization of alanine by the alanine racemases from Salmonella typhimurium and Bacillus stearothermophilus: energetic reaction profiles

    International Nuclear Information System (INIS)

    Faraci, W.S.; Walsh, C.T.

    1988-01-01

    Alanine racemases are bacterial pyridoxal 5'-phosphate (PLP) dependent enzymes providing D-alanine as an essential building block for biosynthesis of the peptidoglycan layer of the cell wall. Two isozymic alanine racemases, encoded by the dadB gene and the alr gene, from the Gram-negative mesophilic Salmonella typhimurium and one from the Gram-positive thermophilic Bacillus stearothermophilus have been examined for the racemization mechanism. Substrate deuterium isotope effects and solvent deuterium isotope effects have been measured in both L → D and D→ L directions for all three enzymes to assess the degree to which abstraction of the α-proton or protonation of substrate PLP carbanion is limiting in catalysis. Additionally, experiments measuring internal return of α- 3 H from substrate to product and solvent exchange/substrate conversion experiments in 3 H 2 O have been used with each enzyme to examine the partitioning of substrate PLP carbanion intermediates and to obtain the relative heights of kinetically significant energy barriers in alanine racemase catalysis

  11. Green reduction of graphene oxide using alanine.

    Science.gov (United States)

    Wang, Jiabin; Salihi, Elif Caliskan; Šiller, Lidija

    2017-03-01

    There remains a real need for the easy, eco-friendly and scalable preparation method of graphene due to various potential applications. Chemical reduction is the most versatile method for the large scale production of graphene. Here we report the operating conditions for a one-step, economical and green synthesis method for the reduction of graphene oxide using a biomolecule (alanine). Graphene oxide was produced by the oxidation and exfoliation of natural graphite flake with strong oxidants using Hummers method (Hummers and Offeman, 1958), but the method was revised in our laboratory to set up a safe and environmentally friendly route. The reduction of graphene oxide was investigated using alanine at various operating conditions in order to set up optimum conditions (treatment time, temperature and concentration of the reagent). Samples have been characterized by using UV-Visible spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectroscopy and X-ray diffraction analysis. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  12. Production of D-alanine from DL-alanine using immobilized cells of Bacillus subtilis HLZ-68.

    Science.gov (United States)

    Zhang, Yangyang; Li, Xiangping; Zhang, Caifei; Yu, Xiaodong; Huang, Fei; Huang, Shihai; Li, Lianwei; Liu, Shiyu

    2017-09-13

    Immobilized cells of Bacillus subtilis HLZ-68 were used to produce D-alanine from DL-alanine by asymmetric degradation. Different compounds such as polyvinyl alcohol and calcium alginate were employed for immobilizing the B. subtilis HLZ-68 cells, and the results showed that cells immobilized using a mixture of these two compounds presented higher L-alanine degradation activity, when compared with free cells. Subsequently, the effects of different concentrations of polyvinyl alcohol and calcium alginate on L-alanine consumption were examined. Maximum L-alanine degradation was exhibited by cells immobilized with 8% (w/v) polyvinyl alcohol and 2% (w/v) calcium alginate. Addition of 400 g of DL-alanine (200 g at the beginning of the reaction and 200 g after 30 h of incubation) into the reaction solution at 30 °C, pH 6.0, aeration of 1.0 vvm, and agitation of 400 rpm resulted in complete L-alanine degradation within 60 h, leaving 185 g of D-alanine in the reaction solution. The immobilized cells were applied for more than 15 cycles of degradation and a maximum utilization rate was achieved at the third cycle. D-alanine was easily extracted from the reaction solution using cation-exchange resin, and the chemical and optical purity of the extracted D-alanine was 99.1 and 99.6%, respectively.

  13. The Emergence of Atomic-Level Structural Information for Ordered Metal-Solution Interfaces: Some Recent Contributions from In-Situ Infrared Spectroscopy and Scanning Tunneling Microscopy

    Science.gov (United States)

    1992-02-28

    Distribution/ Availabilit Codes jAval’ an~d/or Dist Speoial (19. cont.) reconstruction at gold-aqueous interfaces. All three low-index gold surfaces are...uncharged (vide supra). This difference may well be due to the influence of the interfacial water , or conceivably to adsorbed perchlorate anions. Both Au

  14. On the existence of 'L-alanine cadmium bromide'.

    Science.gov (United States)

    Srinivasan, Bikshandarkoil R

    2013-12-01

    It is argued that the recently reported nonlinear optical crystal L-alanine cadmium bromide, grown by slow solvent evaporation method at room temperature [P. Ilayabarathi, J. Chandrasekaran, Spectrochim. Acta 96A (2012) 684-689] is the well-known L-alanine crystal. The isolation of L-alanine crystal is explained due to fractional crystallization. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Calibration of helical tomotherapy machine using EPR/alanine dosimetry.

    Science.gov (United States)

    Perichon, Nicolas; Garcia, Tristan; François, Pascal; Lourenço, Valérie; Lesven, Caroline; Bordy, Jean-Marc

    2011-03-01

    Current codes of practice for clinical reference dosimetry of high-energy photon beams in conventional radiotherapy recommend using a 10 x 10 cm2 square field, with the detector at a reference depth of 10 cm in water and 100 cm source to surface distance (SSD) (AAPM TG-51) or 100 cm source-to-axis distance (SAD) (IAEA TRS-398). However, the maximum field size of a helical tomotherapy (HT) machine is 40 x 5 cm2 defined at 85 cm SAD. These nonstandard conditions prevent a direct implementation of these protocols. The purpose of this study is twofold: To check the absorbed dose in water and dose rate calibration of a tomotherapy unit as well as the accuracy of the tomotherapy treatment planning system (TPS) calculations for a specific test case. Both topics are based on the use of electron paramagnetic resonance (EPR) using alanine as transfer dosimeter between the Laboratoire National Henri Becquerel (LNHB) 60Co-gamma-ray reference beam and the Institut Curie's HT beam. Irradiations performed in the LNHB reference 60Co-gamma-ray beam allowed setting up the calibration method, which was then implemented and tested at the LNHB 6 MV linac x-ray beam, resulting in a deviation of 1.6% (at a 1% standard uncertainty) relative to the reference value determined with the standard IAEA TRS-398 protocol. HT beam dose rate estimation shows a difference of 2% with the value stated by the manufacturer at a 2% standard uncertainty. A 4% deviation between measured dose and the calculation from the tomotherapy TPS was found. The latter was originated by an inadequate representation of the phantom CT-scan values and, consequently, mass densities within the phantom. This difference has been explained by the mass density values given by the CT-scan and used by the TPS which were not the true ones. Once corrected using Monte Carlo N-Particle simulations to validate the accuracy of this process, the difference between corrected TPS calculations and alanine measured dose values was then

  16. Synthesis of 15N isotope labeled alanine

    International Nuclear Information System (INIS)

    Oliveira, Claudineia R. de; Bendassolli, Jose Albertino; Sant'Ana, Carlos Roberto; Tagliassachi, Romulo Barbieri; Maximo, Everaldo; Prestes, Clelber Vieira

    2005-01-01

    The application of light chemical elements and their stable isotopes in biological studies have been increased over the last years. The use of 15 N labeled amino acids is an important tool for elucidation of peptides structures. This paper describe a method for the synthesis of 15 N isotope labeled alanine at lower costs than international ones, as well as the details of the recovery system of the nitrogen residues. In the present work an amination of α-haloacids, with the bromopropionic carboxylic acid and labeled aqua ammonia ( 15 NH 3 aq) was carried out. In order to avoid eventually losses of 15 NH 3 , special cares were adopted, since the production cost is high. Although the acquisition cost of the 13 N (radioactive) labeled compounds is lower, the obtained stable tracer will allow the accomplishment of important studies of the nitrogen cycling in living things, less occupational and environment hazards, and the time limitation problems in field studies. The tests took place in triplicates with NH 3 (aq) being employed. With the establishment of the system for 15 NH 3 recovery, an average of 94 % of the ammonia employed in the synthesis process was recovered. The purity of the amino acid was state determined by TLC (Thin Layer Chromatography) and HPLC (High-Performance Liquid Chromatography) with a fluorescence detector. The Rf and the retention time of the synthesized sample were similar the sigma standard. Finally, regarding the established conditions, it was possible to obtain the alanine with a production cost about 40 % lower than the international price. (author)

  17. The electrochemical interface of Ag(111) in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid—A combined in-situ scanning probe microscopy and impedance study

    International Nuclear Information System (INIS)

    Li, Mian-Gang; Chen, Li; Zhong, Yun-Xin; Chen, Zhao-Bin; Yan, Jia-Wei; Mao, Bing-Wei

    2016-01-01

    The electrochemical interface between Ag(111) and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMITFSI) has been investigated by in-situ scanning probe microscopy (SPM) and electrochemical impedance spectroscopy (EIS). In-situ scanning tunneling microscopy (STM) characterization has revealed that there is neither surface reconstruction nor strong adsorption of EMITFSI on Ag(111) surface so that EIS investigation can be fulfilled under well-defined surface condition and in the absence of pseudo capacitive process. In-situ atom force microscopy (AFM) force curve measurements further disclose that there exists five layered structures near and normal to the surface, among them three layered structures being charged and forming the electric double layer (EDL) of the interface. An electric equivalent circuit is proposed, which comprises two serial parallel branches involving the innermost layered structure and the next two layered structures in the EDL, respectively. The inner layer circuit is given by a constant phase element (CPE) in parallel to a resistor, while the outer layer circuit is given by a capacity in parallel with a resistor-Warburg element branch. Slow response is observed for the inner layer, which is attributed to the hindrance of reorientation and/or redistribution of ions in the more ordered and robust inner layer region. The inner layer capacitance and outer layer capacitance have opposing potential dependence, and the resultant double layer capacitance shows weak potential dependence.

  18. Alanine repeats influence protein localization in splicing speckles and paraspeckles.

    Science.gov (United States)

    Chang, Shuo-Hsiu; Chang, Wei-Lun; Lu, Chia-Chen; Tarn, Woan-Yuh

    2014-12-16

    Mammalian splicing regulatory protein RNA-binding motif protein 4 (RBM4) has an alanine repeat-containing C-terminal domain (CAD) that confers both nuclear- and splicing speckle-targeting activities. Alanine-repeat expansion has pathological potential. Here we show that the alanine-repeat tracts influence the subnuclear targeting properties of the RBM4 CAD in cultured human cells. Notably, truncation of the alanine tracts redistributed a portion of RBM4 to paraspeckles. The alanine-deficient CAD was sufficient for paraspeckle targeting. On the other hand, alanine-repeat expansion reduced the mobility of RBM4 and impaired its splicing activity. We further took advantage of the putative coactivator activator (CoAA)-RBM4 conjoined splicing factor, CoAZ, to investigate the function of the CAD in subnuclear targeting. Transiently expressed CoAZ formed discrete nuclear foci that emerged and subsequently separated-fully or partially-from paraspeckles. Alanine-repeat expansion appeared to prevent CoAZ separation from paraspeckles, resulting in their complete colocalization. CoAZ foci were dynamic but, unlike paraspeckles, were resistant to RNase treatment. Our results indicate that the alanine-rich CAD, in conjunction with its conjoined RNA-binding domain(s), differentially influences the subnuclear localization and biogenesis of RBM4 and CoAZ. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

  19. Medical reference dosimetry using EPR measurements of alanine

    DEFF Research Database (Denmark)

    Helt-Hansen, Jakob; Rosendal, F.; Kofoed, I.M.

    2009-01-01

    Background. Electron spin resonance (EPR) is used to determine the absorbed dose of alanine dosimeters exposed to clinical photon beams in a solid-water phantom. Alanine is potentially suitable for medical reference dosimetry, because of its near water equivalence over a wide energy spectrum, low...... methods the proposed algorithm can be applied without normalisation of phase shifts caused by changes in the g-value of the cavity. The study shows that alanine dosimetry is a suitable candidate for medical reference dosimetry especially for quality control applications.......Background. Electron spin resonance (EPR) is used to determine the absorbed dose of alanine dosimeters exposed to clinical photon beams in a solid-water phantom. Alanine is potentially suitable for medical reference dosimetry, because of its near water equivalence over a wide energy spectrum, low...

  20. Complexation of vanadium (v) with alanine in different ionic strength

    International Nuclear Information System (INIS)

    Garib, F.; Zare, K.; Fekri, H

    2002-01-01

    The formation constants of species formed in the system H ++ alanine and VO 2 + alanine have be determined in aqueous solution for 1.0 3 NaCIO 4 ,using a combination of pramiracetam and spectrophotometric techniques. The compositions of the formed complexes and their stability constants were determined ny curve fitting method and it was shown that di oxovanadium(V) forms two mononuclear 1:1 and 1:2 species with alanine of the type VO 2 L and VO 2 L 2 The protonation constant of the amino group of alanine has been determined using a computer program which employ a least-squares method. The defence of the protonation of alanine and the stability constant of the species on ionic strength are described by a Debby-huckel type equation

  1. Comparison of EPR response of alanine and Gd₂O₃-alanine dosimeters exposed to TRIGA Mainz reactor.

    Science.gov (United States)

    Marrale, M; Schmitz, T; Gallo, S; Hampel, G; Longo, A; Panzeca, S; Tranchina, L

    2015-12-01

    In this work we report some preliminary results regarding the analysis of electron paramagnetic resonance (EPR) response of alanine pellets and alanine pellets added with gadolinium used for dosimetry at the TRIGA research reactor in Mainz, Germany. Two set-ups were evaluated: irradiation inside PMMA phantom and irradiation inside boric acid phantom. We observed that the presence of Gd2O3 inside alanine pellets increases the EPR signal by a factor of 3.45 and 1.24 in case of PMMA and boric acid phantoms, respectively. We can conclude that in the case of neutron beam with a predominant thermal neutron component the addition of gadolinium oxide can significantly improve neutron sensitivity of alanine pellets. Monte Carlo (MC) simulations of both response of alanine and Gd-added alanine pellets with FLUKA code were performed and a good agreement was achieved for pure alanine dosimeters. For Gd2O3-alanine deviations between MC simulations and experimental data were observed and discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Synthesis and characterization of new nanocomposites films using alanine-Cu-functionalized graphene oxide as nanofiller and PVA as polymeric matrix for improving of their properties

    Science.gov (United States)

    Abdolmaleki, Amir; Mallakpour, Shadpour; Karshenas, Azam

    2017-09-01

    In the synthesis of polymer-graphene nanocomposites, for improving properties of nanocomposites, two factors dispersion and strong interfacial interactions between graphene and the polymer, are essential. In the present work, poly(vinyl alcohol) PVA/GO-Cu-alanine nanocomposite films were manufactured using concentrations 0, 1, 3 and 5 wt% of GO-Cu-alanine in water solution. For this purpose, L-alanine amino acid was located on the surface and edges of GO through copper(II) ion as a coordinating function. Then, flexible PVA/GO-Cu-alanine nanocomposite films were fabricated using GO-Cu-alanine as filler and PVA as matrix. Due to the existence of affective interaction between GO-Cu-alanine and PVA matrix, the acquired PVA/GO-Cu-alanine nanocomposites demonstrated great thermal and mechanical properties. Properties of manufactured materials were characterized by Fourier transform infrared, X-ray photoelectron spectroscopies (XPS), X-ray diffraction (XRD), Thermal gravimetric analysis, elemental analysis, field emission scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray spectroscopy (EDX).

  3. Water-resistant alanine-EPR dosimeter alanpol

    International Nuclear Information System (INIS)

    Peimel-Stuglik, Zofia; Bryl-Sandelewska, Teresa; Mirkowski, Krzysztof; Sartowska, Bozena

    2009-01-01

    Alanpol-water-resistant alanine-electron paramagnetic resonance (EPR) dosimeter consisted of cheap DL-α-alanine (9.8-27%) suspended in polyethylene matrix was presented. The rods (O=2.8 mm) were extruded from a hot mixture of alanine and low-density polyethylene. No grinding or crushing was used for alanine preparation. An orientation of cylindrical crystals, up to 300 μm long in parallel to the rod axis was responsible for some differences in a shape of EPR signal. These differences had no negative consequences for dosimetric applications. Signal-to-dose dependence was linear up to 10 kGy. Standard deviation of dosimetric answer was up to ±1.8% and up to 2.4% for dosimeters with 9.8% and 27% of DL-α-alanine, respectively. Irradiation temperature coefficient for both dosimeters was equal 0.2%/ deg. C. Hydrophobic properties of polyethylene and small number of alanine crystals located on the surface of the rod led to high resistance of dosimeters to water and humidity. The 24 h soaking of irradiated dosimeters in liquid water-reduced EPR signals by 3-4% and by 2-3% for dosimeters with 27% and 9.8% of DL-α-alanine, respectively. Three month storage time of irradiated dosimeters in room conditions decreases EPR signal for ∼3%.

  4. Reactivity at the film/solution interface of ex situ prepared bismuth film electrodes: A scanning electrochemical microscopy (SECM) and atomic force microscopy (AFM) investigation

    International Nuclear Information System (INIS)

    Hocevar, Samo B.; Daniele, Salvatore; Bragato, Carlo; Ogorevc, Bozidar

    2007-01-01

    Bismuth film electrodes (BiFEs) prepared ex situ with and without complexing bromide ions in the modification solution were investigated using scanning electrochemical microscopy (SECM) and atomic force microscopy (AFM). A feedback mode of the SECM was employed to examine the conductivity and reactivity of a series of thin bismuth films deposited onto disk glassy carbon substrate electrodes (GCEs) of 3 mm in diameter. A platinum micro-electrode (φ = 25 μm) was used as the SECM tip, and current against tip/substrate distance was recorded in solutions containing either Ru(NH 3 ) 6 3+ or Fe(CN) 6 4- species as redox mediators. With both redox mediators positive feedback approach curves were recorded, which indicated that the bismuth film deposition protocol associated with the addition of bromide ions in the modification solution did not compromise the conductivity of the bismuth film in comparison with that prepared without bromide. However, at the former Bi film a slight kinetic hindering was observed in recycling Ru(NH 3 ) 6 3+ , suggesting a different surface potential. On the other hand, the approach curves recorded by using Fe(CN) 6 4- showed that both types of the aforementioned bismuth films exhibited local reactivity with the oxidised form of the redox mediator, and that bismuth film obtained with bromide ions exhibited slightly lower reactivity. The use of SECM in the scanning operation mode allowed us to ascertain that the bismuth deposits were uniformly distributed across the whole surface of the glassy carbon substrate electrode. Comparative AFM measurements corroborated the above findings and additionally revealed a denser growth of smaller bismuth crystals over the surface of the substrate electrode in the presence of bromide ions, while the crystals were bigger but sparser in the absence of bromide ions in the modification solution

  5. The antiproton depth–dose curve measured with alanine detectors

    CERN Document Server

    Bassler, Niels; Palmans, Hugo; Holzscheiter, Michael H; Kovacevic, Sandra

    2008-01-01

    n this paper we report on the measurement of the antiproton depth–dose curve, with alanine detectors. The results are compared with simulations using the particle energy spectrum calculated by FLUKA, and using the track structure model of Hansen and Olsen for conversion of calculated dose into response. A good agreement is observed between the measured and calculated relative effectiveness although an underestimation of the measured values beyond the Bragg-peak remains unexplained. The model prediction of response of alanine towards heavy charged particles encourages future use of the alanine detectors for dosimetry of mixed radiation fields.

  6. The Antiproton Depth Dose Curve Measured with Alanine Detectors

    DEFF Research Database (Denmark)

    Bassler, Niels; Hansen, Johnny Witterseh; Palmans, Hugo

    2008-01-01

    In this paper we report on the measurement of the antiproton depth dose curve, with alanine detectors. The results are compared with simulations using the particle energy spectrum calculated by FLUKA, and using the track structure model of Hansen et Olsen for conversion of calculated dose...... into response. A good agreement was observed between the measured and calculated relative effectiveness although a slight underestimation of the calculated values in the Bragg peak remains unexplained. The model prediction of response of alanine towards heavy charged particles encourages future use...... of the alanine detectors for dosimetry of mixed radiation fields....

  7. Alanine EPR dosimeter response in proton therapy beams

    International Nuclear Information System (INIS)

    Gall, K.; Serago, C.; Desrosiers, M.; Bensen, D.

    1997-01-01

    We report a series of measurements directed to assess the suitability of alanine as a mailable dosimeter for dosimetry quality assurance of proton radiation therapy beams. These measurements include dose-response of alanine at 140 MeV, and comparison of response vs energy with a parallel plate ionization chamber. All irradiations were made at the Harvard Cyclotron Laboratory, and the dosimeters were read at NIST. The results encourage us that alanine could be expected to serve as a mailable dosimeter with systematic error due to differential energy response no greater than 3% when doses of 25 Gy are used. (Author)

  8. Alanine-ESR dosimetry for radiotherapy IAEA experience

    International Nuclear Information System (INIS)

    Mehta, K.; Girzikowsky, R.; )

    1997-01-01

    At present, the most commonly used transfer dosimeters for radiotherapy applications are TL dosemeters. They are being used for intercomparison between SSDLs (about 70) and the IAEA dosimetry laboratory. However, there are some undesirable characteristics of this dosimetry system. We have a study in progress at the IAEA to evaluate the alanine-ESR systems as an alternative to TLDs. There are several desirable qualities which make alanine an attractive dosemeter. Preliminary data suggest that the alanine-ESR dosimetry system has the potential to replace TLDs for intercomparison amongst SSDLs in the therapy-level dose regions. (Author)

  9. Application of x-ray nano-particulate markers for the visualization of intermediate layers and interfaces using scanning electron microscopy

    Science.gov (United States)

    Bessudnova, Nadezda O.; Bilenko, David I.; Zakharevich, Andrey M.

    2012-03-01

    In this study the methodology of biological sample preparation for dental research using SEM/EDX has been elaborated. (1)The original cutting equipment supplied with 3D user-controlled sample fixation and an adjustable cooling system has been designed and evaluated. (2) A new approach to the root dentine drying procedure has been developed to preserve structure peculiarities of root dentine. (3) A novel adhesive system with embedded X-Ray nanoparticulate markers has been designed. (4)The technique allowing for visualization of bonding resins, interfaces and intermediate layers between tooth hard tissues and restorative materials of endodontically treated teeth using the X-ray nano-particulate markers has been developed and approved. These methods and approaches were used to compare the objective depth of penetration of adhesive systems of different generations in root dentine. It has been shown that the depth of penetration in dentine is less for adhesive systems of generation VI in comparison with bonding resins of generation V, which is in agreement with theoretical evidence. The depth of penetration depends on the correlation between the direction of dentinal tubules, bonding resin delivery and gravity.

  10. Isotopic effects in mechanistic studies of biotransformations of fluorine derivatives of L-alanine catalysed by L-alanine dehydrogenase

    International Nuclear Information System (INIS)

    Szymańska-Majchrzak, Jolanta; Pałka, Katarzyna; Kańska, Marianna

    2017-01-01

    Synthesis of 3-fluoro-[2- 2 H]-L-alanine (3-F-[ 2 H]-L-Ala) in reductive amination of 3-fluoropyruvic acid catalysed by L-alanine dehydrogenase (AlaDH) was described. Fluorine derivative was used to study oxidative deamination catalysed by AlaDH applied kinetic (for 3-F-L-Ala in H 2 O - KIE’s on V max : 1.1; on V max /K M : 1.2; for 3-F-L-Ala in 2 H 2 O – on V max : 1.4; on V max /K M : 2.1) and solvent isotope effect methods (for 3-F-L-Ala - SIE’s on V max : 1.0; on V max /K M : 0.87; for 3-F-[2- 2 H]-L-Ala – on V max : 1.4; on V max /K M : 1.5). Studies explain some details of reaction mechanism. - Highlights: • Synthesis of 3-fluoro-[2- 2 H]-L-alanine was performed. • The reactions were catalysed using the enzyme L-alanine dehydrogenase. • Performed reactions involved fluorinated analogues of L-alanine. • Solvent isotope effects of deuterium were determined. • Kinetic isotope effects were determined for obtained 3-fluoro-L-alanine. • The mechanism of reaction catalysed by L-alanine dehydrogenase was proposed.

  11. Nuclear Scans

    Science.gov (United States)

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  12. Dosimetry auditing procedure with alanine dosimeters for light ion beam therapy

    International Nuclear Information System (INIS)

    Ableitinger, Alexander; Vatnitsky, Stanislav; Herrmann, Rochus; Bassler, Niels; Palmans, Hugo; Sharpe, Peter; Ecker, Swantje; Chaudhri, Naved; Jäkel, Oliver; Georg, Dietmar

    2013-01-01

    Background and purpose: In the next few years the number of facilities providing ion beam therapy with scanning beams will increase. An auditing process based on an end-to-end test (including CT imaging, planning and dose delivery) could help new ion therapy centres to validate their entire logistic chain of radiation delivery. An end-to-end procedure was designed and tested in both scanned proton and carbon ion beams, which may also serve as a dosimetric credentialing procedure for clinical trials in the future. The developed procedure is focused only on physical dose delivery and the validation of the biological dose is out of scope of the current work. Materials and methods: The audit procedure was based on a homogeneous phantom that mimics the dimension of a head (20 × 20 × 21 cm 3 ). The phantom can be loaded either with an ionisation chamber or 20 alanine dosimeters plus 2 radiochromic EBT films. Dose verification aimed at measuring a dose of 10 Gy homogeneously delivered to a virtual-target volume of 8 × 8 × 12 cm 3 . In order to interpret the readout of the irradiated alanine dosimeters additional Monte Carlo simulations were performed to calculate the energy dependent detector response of the particle fluence in the alanine detector. A pilot run was performed with protons and carbon ions at the Heidelberg Ion Therapy facility (HIT). Results: The mean difference of the absolute physical dose measured with the alanine dosimeters compared with the expected dose from the treatment planning system was −2.4 ± 0.9% (1σ) for protons and −2.2 ± 1.1% (1σ) for carbon ions. The measurements performed with the ionisation chamber indicate this slight underdosage with a dose difference of −1.7% for protons and −1.0% for carbon ions. The profiles measured by radiochromic films showed an acceptable homogeneity of about 3%. Conclusions: Alanine dosimeters are suitable detectors for dosimetry audits in ion beam therapy and the presented end-to-end test is

  13. Dosimetry auditing procedure with alanine dosimeters for light ion beam therapy.

    Science.gov (United States)

    Ableitinger, Alexander; Vatnitsky, Stanislav; Herrmann, Rochus; Bassler, Niels; Palmans, Hugo; Sharpe, Peter; Ecker, Swantje; Chaudhri, Naved; Jäkel, Oliver; Georg, Dietmar

    2013-07-01

    In the next few years the number of facilities providing ion beam therapy with scanning beams will increase. An auditing process based on an end-to-end test (including CT imaging, planning and dose delivery) could help new ion therapy centres to validate their entire logistic chain of radiation delivery. An end-to-end procedure was designed and tested in both scanned proton and carbon ion beams, which may also serve as a dosimetric credentialing procedure for clinical trials in the future. The developed procedure is focused only on physical dose delivery and the validation of the biological dose is out of scope of the current work. The audit procedure was based on a homogeneous phantom that mimics the dimension of a head (20 × 20 × 21 cm(3)). The phantom can be loaded either with an ionisation chamber or 20 alanine dosimeters plus 2 radiochromic EBT films. Dose verification aimed at measuring a dose of 10Gy homogeneously delivered to a virtual-target volume of 8 × 8 × 12 cm(3). In order to interpret the readout of the irradiated alanine dosimeters additional Monte Carlo simulations were performed to calculate the energy dependent detector response of the particle fluence in the alanine detector. A pilot run was performed with protons and carbon ions at the Heidelberg Ion Therapy facility (HIT). The mean difference of the absolute physical dose measured with the alanine dosimeters compared with the expected dose from the treatment planning system was -2.4 ± 0.9% (1σ) for protons and -2.2 ± 1.1% (1σ) for carbon ions. The measurements performed with the ionisation chamber indicate this slight underdosage with a dose difference of -1.7% for protons and -1.0% for carbon ions. The profiles measured by radiochromic films showed an acceptable homogeneity of about 3%. Alanine dosimeters are suitable detectors for dosimetry audits in ion beam therapy and the presented end-to-end test is feasible. If further studies show similar results, this dosimetric audit could be

  14. [Scanning electron microscopy observation of the growth of osteoblasts on Ti-24Nb-4Zr-8Sn modified by micro-arc oxidation and alkali-heat treatment and implant-bone interface].

    Science.gov (United States)

    Han, Xue; Liu, Hong-Chen; Wang, Dong-Sheng; Li, Shu-Jun; Yang, Rui

    2011-01-01

    To observe the efficacy of micro-arc oxidation and alkali-heat treatment (MAH) on Ti-24Nb-4Zr-8Sn (Ti2448). Disks (diameter of 14.5 mm, thickness of 1 mm) and cylinders (diameter of 3 mm, height of 10 mm) were fabricated from Ti2448 alloy. Samples were divided into three groups: polished (Ti2448), micro-arc oxidation(MAO-Ti2448), micro-arc oxidation and alkali-heat treatment (MAH-Ti2448). MC3T3-E1 osteoblastic cells were cultured on the disks and cell morphology was observed with scanning electron microscopy (SEM) aftre 3 days. The cylinder samples were implanted in the tibia of dogs and implant-bone interface was observed with SEM after 3 months. A rough and porous structure was shown in both MAO and MAH group. The MC3T3-E1 cells on the MAH-Ti2448 discs spread fully in intimate contact with the underlying coarse surface through active cytoskeletal extentions. Osseointegration was formed in the implant-bone interface in MAH samples. MAH treatment can provide a more advantageous Ti2448 surface to osteoblastic cells than MAO treatment does, and the former can improve the implant-bone integration.

  15. Reproducibility and signal response linearity of Alanine gel dosimeter

    International Nuclear Information System (INIS)

    Silva, Cleber Feijo Silva; Campos, Leticia Lucente

    2008-01-01

    Gel Dosimetry has been studied mainly for medical applications, because it presents signal response in the dose range used in radiotherapy treatments and it can be applied for three dimensional dosimetry. Alanine gel dosimeter is a new gel material developed at IPEN that presents significant improvement on previous alanine systems developed by Costa (1994). The DL-Alanine (C 3 H 7 NO 2 ) is an amino acid tissue equivalent that improves the production of ferric ions in the solution. These ferric ions concentration can be measured by spectrophotometry technique. This work aims to study the reproducibility of the alanine gel solutions and the signal response as a function of gamma radiation dose, considering that these two properties are very important for characterizing and standardizing any dosimeter. (author)

  16. Alanine administration does not stimulate gluconeogenesis in preterm infants

    NARCIS (Netherlands)

    van Kempen, Anne A. M. W.; Romijn, Johannes A.; Ruiter, An F. C.; Endert, Erik; Weverling, Gerrit Jan; Kok, Johanna H.; Sauerwein, Hans P.

    2003-01-01

    Gluconeogenesis partially depends on sufficient precursor supply, and plasma alanine concentrations are generally low in preterm infants. Stimulation of gluconeogenesis may contribute to the prevention of hypoglycemia, an important clinical problem in these infants. In this study we evaluated the

  17. A High Sensitivity EPR Technique for Alanine Dosimetry (invited paper)

    International Nuclear Information System (INIS)

    Haskell, E.H.; Hayes, R.B.; Kenner, G.H.

    1998-01-01

    Uncertainties of ± 5 mGy were achieved in the measurement of alanine dosemeters using optimised EPR parameters, instrumentation, spectral manipulation and subtraction techniques. Modulation amplitude and microwave power were adjusted to combine resonances of two neighbouring alanine signals. Instrumental variations were minimised by combining and subtracting pre- and post-measurement spectra of the empty EPR tube. A spectrum of the native signal of non-dosed alanine was generated from a single batch of dosemeters and subtracted from spectra of the irradiated dosemeters, also from the same batch. Field alignment was adjusted with the use of an in-cavity Mn ++ standard. A constant rotation goniometer was used to eliminate anisotropies in the EPR tube and alanine samples. Finally, digital filters were applied to the resulting spectra. (author)

  18. Dosimetry of electron and gamma radiation with DL-alanine

    International Nuclear Information System (INIS)

    Costa, Z.M. da; Campos, L.L.

    1996-01-01

    A dosimetric method based on the quantitative determination of stabilised free radicals in irradiated crystalline DL-alanine by electron spin resonance (ESR) spectroscopy was proposed as early in 1962. Since then, alanine dosemeters owing to their unique properties have been investigated by many authors and used in dosimetry of various types of radiation, namely gamma rays, electron and neutrons. Alanine is a simple aminoacid, on irradiation at room temperature predominantly free paramagnetic radicals of the type CH 3 -CH-COOH are produced. This paper reports the application of powder DL-alanine/ESR dosemeter for measurement of absorbed dose of gamma radiation from 60 Co sources and reactor nucleus and electron beams from accelerator. The obtained results give useful information about the instrumental care necessary to obtain the needed overall accuracy in determination of absorbed dose. (author)

  19. Conductivity of alanine solution for high level dosimetry

    International Nuclear Information System (INIS)

    Wieser, A.; Figel, M.; Regulla, D.F.

    1993-01-01

    The amino acid alanine is well known as a dosimetric detector material for high level dosimetry. Its application is based on the formation of radicals by ionising radiation. The free radicals are earlier detected by electron spin resonance (ESR) spectroscopy or chemically after dissolving the irradiated samples. Of all these methods the ESR/alanine system is the most advanced and is suggested for reference dosimetry. At present, however, the high cost of the system is a serious handicap for a large scale routine application in radiation plants. In this study the variation of electrical conductivity of L-alanine solution with applied dose is investigated in the range from 0.5-200 kGy. The conductivity was measured with a 50 MHz RF oscillator. This readout method is uncomplicated and may be suitable for routine application. The experiments were performed with L-alanine solution in glass ampoules. (Author)

  20. Postirradiation effects in alanine dosimeter probes of two different suppliers

    International Nuclear Information System (INIS)

    Anton, Mathias

    2008-01-01

    The measurand relevant for the dosimetry for radiation therapy is the absorbed dose to water, D W . The Physikalisch-Technische Bundesanstalt (PTB) is establishing a secondary standard for D W for high-energy photon and electron radiation based on electron spin resonance (ESR) of the amino acid alanine. For practical applications, like, for example, intercomparison measurements using the ESR/alanine dosimetry system, the temporal evolution of the ESR signal of irradiated probes is an important issue. This postirradiation behaviour is investigated for alanine pellets of two different suppliers for different storage conditions. The influence of the storage conditions on the temporal evolution may be dependent on the type of probes used. The measurement and analysis method developed at the PTB is able to circumvent the apparent difficulties in the case of alanine/paraffin probes. Care has to be taken in case this method cannot be applied

  1. Asymmetric adsorption of alanine by quartz powder from ethanol solution

    Energy Technology Data Exchange (ETDEWEB)

    Furuyama, Shozo; Sawada, Michio; Hachiya, Kinji; Morimoto, Tetsuo (Okayama Univ. (Japan). Faculty of Science)

    1982-11-01

    The asymmetric adsorption of the racemic alanine by the optically active quartz from ethanol solution at 8/sup 0/C was studied by the /sup 14/C-tracer method and the newly developed /sup 14/C-tracer ninhydrin-colorimetry combination method. The preferential adsorption of L-alanine by levorotatory quartz (l-quartz) and D-alanine by dextrorotatory quartz (d-quartz) was confirmed. The asymmetric adsorptivity (Asub(s)) falls in the range of 1.1 - 1.3, which is comparable with the value determined at - 80/sup 0/C in the previous paper. The effects of water content in the ethanol solution and of the adsorption temperature upon the adsorption affinity of alanine to quartz were also measured. The cause for the asymmetric adsorption is discussed from the crystallographic point of view.

  2. Alanine turnover in the postabsorptive state and during parenteral hyperalimentation before and after surgery

    NARCIS (Netherlands)

    Sauerwein, H. P.; Michels, R. P.; Cejka, V.

    1981-01-01

    Influence of total parenteral nutrition and operation on alanine turnover and venous alanine concentration was determined in 5 patients with stomach carcinoma using single technique of U-14C alanine. Every patient served at his own control. In the postabsorptive state alanine turnover was 1.63 +/-

  3. Protein-protein interface detection using the energy centrality relationship (ECR characteristic of proteins.

    Directory of Open Access Journals (Sweden)

    Sanjana Sudarshan

    Full Text Available Specific protein interactions are responsible for most biological functions. Distinguishing Functionally Linked Interfaces of Proteins (FLIPs, from Functionally uncorrelated Contacts (FunCs, is therefore important to characterizing these interactions. To achieve this goal, we have created a database of protein structures called FLIPdb, containing proteins belonging to various functional sub-categories. Here, we use geometric features coupled with Kortemme and Baker's computational alanine scanning method to calculate the energetic sensitivity of each amino acid at the interface to substitution, identify hotspots, and identify other factors that may contribute towards an interface being FLIP or FunC. Using Principal Component Analysis and K-means clustering on a training set of 160 interfaces, we could distinguish FLIPs from FunCs with an accuracy of 76%. When these methods were applied to two test sets of 18 and 170 interfaces, we achieved similar accuracies of 78% and 80%. We have identified that FLIP interfaces have a stronger central organizing tendency than FunCs, due, we suggest, to greater specificity. We also observe that certain functional sub-categories, such as enzymes, antibody-heavy-light, antibody-antigen, and enzyme-inhibitors form distinct sub-clusters. The antibody-antigen and enzyme-inhibitors interfaces have patterns of physical characteristics similar to those of FunCs, which is in agreement with the fact that the selection pressures of these interfaces is differently evolutionarily driven. As such, our ECR model also successfully describes the impact of evolution and natural selection on protein-protein interfaces. Finally, we indicate how our ECR method may be of use in reducing the false positive rate of docking calculations.

  4. A method to improve application technique in Alanine/ESR dosimetry

    International Nuclear Information System (INIS)

    Choi, Hoon; Ha, Ju Hee; Choi, Won; Lim, Young Khi

    2008-01-01

    Full text: For long-term radiation monitoring to assess the cable aging in harsh condition of nuclear power plant, ESR dosimetry method using alanine dosimeters was already recommended in many technical document and paper. Several ESR dosimetry systems were already produced and used widely, but the actual application of these systems for industrial dosimetry needs careful consideration of error sources in process of dose measurement. The alanine dosimeters were measured by E-scan alanine analyzer system or EMX ESR spectrometer. For the accurate measurement of the dosimeters, we have studied various source of errors. First, this paper discusses sources of inaccuracy related to data processing. To make a meaningful dose assessment, the dosimeter measurements need to be compared with measurements made using certified dosimeters of known dose. This is achieved by performing the routine calibration procedure which creates a calibration curve and corresponding fit coefficients from measurements made with a set of dosimeters with known certified dose. The calibration curves in ESR dosimetry are usually constructed by means of the least-squares technique in its simplest variant. The recommended alternative linearity several replicate measurements of Y at each used X value. Also, measurement is subject to error, so repeat measurements will not be identical. A technical description of a linear calibration is assumed that the dispersion of the measurements is the same for each standard. But in some cases, the standard deviation has to be specified separately for each value of concentration. In this case, it used the WLS (Weighted Least-Squared Regression) method instead of the OLS (Ordinary Least-Squared Regression) method. Second, the precision of the ESR spectrum was showed as a reproducibility test for the two ESR systems. The reproducibility test was performed at an absorbed dose of 1 k Gy, which is at least three orders of magnitude above the background reading of an

  5. A comparative microleakage evaluation of three different base materials in Class I cavity in deciduous molars in sandwich technique using dye penetration and dentin surface interface by scanning electron microscope

    Directory of Open Access Journals (Sweden)

    Babita Niranjan

    2016-01-01

    Full Text Available Introduction: A major objective in restorative dentistry is the control of marginal leakage, which may occur because of dimensional changes or lack of adaptation of restorative material to the cavity preparation. Numerous techniques have been advocated to overcome polymerization shrinkage in composite restorations. Aim and Objectives: This study investigated microleakage of three different bases under composite resin in sandwich technique using dye penetration and dentin surface interface using scanning electron microscope (SEM. Materials and Methods: Sixty extracted deciduous molars were stored in distilled water and Class I cavities with a width of about one-fourth of intercuspal distance and a depth of 0.5-1 mm below the dentino-enamel junction was prepared without bevels. In Group 1 - glass ionomer cement (GIC; Group 2 - mineral trioxide aggregate (MTA; Group 3 - Biodentine™ was placed as a base under composite. Teeth were longitudinally sectioned in two halves, through the centers of the restoration, immersed in 2% methylene blue and microleakage was evaluated under stereomicroscope and surface interface between base and dentin was evaluated under SEM. Results:Under the condition of in vitro study, less microleakage and less internal gaps were seen in Biodentine™ (0.00 ± 0.00 and 4.00 ± 1.59 group than MTA (0.00 ± 0.00 and 6.08 ± 1.82 and GIC (25.25 ± 6.57 and 14.73 ± 3.72, respectively and showed very strong positive correlation between microleakage and internal gaps. Conclusion: Biodentine™ exhibits superior marginal sealing ability as well as marginal adaptation under composite resin as compared to MTA and GIC.

  6. Renal scan

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003790.htm Renal scan To use the sharing features on this ... anaphylaxis . Alternative Names Renogram; Kidney scan Images Kidney anatomy Kidney - blood and urine flow References Chernecky CC, ...

  7. CT Scan

    Science.gov (United States)

    ... disease, lung nodules and liver masses Monitor the effectiveness of certain treatments, such as cancer treatment Detect ... scan done in a hospital or an outpatient facility. CT scans are painless and, with newer machines, ...

  8. Control of alanine metabolism in rat liver by transport processes or cellular metabolism.

    OpenAIRE

    Fafournoux, P; Rémésy, C; Demigné, C

    1983-01-01

    1. Factors governing hepatic utilization of alanine were studied in vivo and in vitro in rats adapted to increasing dietary protein. 2. Hepatic alanine utilization was enhanced 5-fold with a 90%-casein diet, compared with a 13%-casein diet. The increased uptake resulted from enhanced fractional extraction in the presence of high concentrations of alanine in the portal vein. 3. The increase in alanine metabolism on high-protein diets was associated with an increase in alanine aminotransferase ...

  9. EPR structure of the gamma irradiated alanine spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Cabral P, A; Jimenez D, H; Urena N, F; Galindo, S; Bosch, P

    1992-03-15

    In this study is shown that the broadened five-line EPR pattern of the gamma irradiated alanine possibly decomposes into a more complex pattern when the recorded spectrum is subject to an operation of deconvolution. The EPR powder spectra of gamma irradiated DL- and L-alanine with and without binders are analysed. In all recorded spectra, each observed line is resolved into an asymmetrical triplet when a Gaussian distribution of 8.2 gauss width is removed, by deconvolution, from the observed spectrum. On the other hand, from a simple fitting analysis carried out on the original data, one encounters that some calculated relations between characteristic parameters, such as intensity ratios, deviate consistently from assumed height ratios. Both, from deconvolution and fitting results, a different structure is suggested for the observed broadened five-line EPR pattern of {gamma}-irradiated powder DL- and L-alanine. (Author)

  10. Effects of dose fractionation on the response of alanine dosimetry

    International Nuclear Information System (INIS)

    Lundahl, Brad; Logar, John; Desrosiers, Marc; Puhl, James

    2014-01-01

    Alanine dosimetry is well established as a transfer standard and is becoming more prevalently used in routine dosimetry systems for radiation processing. Many routine measurement applications in radiation processing involve absorbed dose measurements resulting from fractioned exposures to ionizing radiation. Fractioning of absorbed dose is identified as an influence quantity (ISO/ASTM, 2013). This paper reports on study results of absorbed dose fractioning characteristics of alanine for gamma and high energy electron beam radiation sources. The results of this study indicate a radiation response difference due to absorbed dose fractioning in response can be observed after four fractionations for high-energy electron beams and no difference up to seven fractions for gamma rays using an ANOVA evaluation method. - Highlights: • Fractioning effects signaled in electron beam using an ANOVA at 6 equal increments. • Fractioning effects not signaled in gamma using an ANOVA up to 7 equal increments. • Insensitivity of alanine to dose fractioning indicates nominal impact on calibration

  11. EPR structure of the gamma irradiated alanine spectrum

    International Nuclear Information System (INIS)

    Cabral P, A.; Jimenez D, H.; Urena N, F.; Galindo, S.; Bosch, P.

    1992-03-01

    In this study is shown that the broadened five-line EPR pattern of the gamma irradiated alanine possibly decomposes into a more complex pattern when the recorded spectrum is subject to an operation of deconvolution. The EPR powder spectra of gamma irradiated DL- and L-alanine with and without binders are analysed. In all recorded spectra, each observed line is resolved into an asymmetrical triplet when a Gaussian distribution of 8.2 gauss width is removed, by deconvolution, from the observed spectrum. On the other hand, from a simple fitting analysis carried out on the original data, one encounters that some calculated relations between characteristic parameters, such as intensity ratios, deviate consistently from assumed height ratios. Both, from deconvolution and fitting results, a different structure is suggested for the observed broadened five-line EPR pattern of γ-irradiated powder DL- and L-alanine. (Author)

  12. Alanine Radiation Detectors in Therapeutic Carbon Ion Beams

    DEFF Research Database (Denmark)

    Herrmann, Rochus; Jäkel, Oliver; Palmans, Hugo

    of the depth dose curves. Solid state detectors, such as diamond detectors, radiochromic films, TLDs and the amino acid alanine are used due to there good spatial resolution. If used in particle beams their response often exhibits a dependence on particle energy and type, so the acquired signal is not always...... proportional to absorbed dose. A model by Hansen and Olsen, based on the Track Structure Theory is available, which can predict the relative efficiency of some detectors, when the particle spectrum is known. For alanine detectors the model was successfully validated by Hansen and Olsen for several ion species...... at energies below 20 MeV/u. We implemented this model in the Monte Carlo code FLUKA. At the GSI heavy ion facility in Darmstadt, Germany, alanine has been irradiated with carbon ions at energies between 88 an 400 MeV/u, which is the energy range used for therapy. The irradiation and the detector response have...

  13. Structure and Intramolecular Proton Transfer of Alanine Radical Cations

    International Nuclear Information System (INIS)

    Lee, Gab Yong

    2012-01-01

    The structures of the four lowest alanine conformers, along with their radical cations and the effect of ionization on the intramolecular proton transfer process, are studied using the density functional theory and MP2 method. The energy order of the radical cations of alanine differs from that of the corresponding neutral conformers due to changes in the basicity of the NH 2 group upon ionization. Ionization favors the intramolecular proton transfer process, leading to a proton-transferred radical-cation structure, [NH 3 + -CHCH 3 -COO·], which contrasts with the fact that a proton-transferred zwitterionic conformer is not stable for a neutral alanine in the gas phase. The energy barrier during the proton transfer process is calculated to be about 6 kcal/mol

  14. The features of radiation damages in L-alanine crystals

    International Nuclear Information System (INIS)

    Zaitov, V.R.; Onischuk, V.A.

    1996-01-01

    The method of the ESR alanine dosimetry has appeared the most convenient one for measurement of radiation dose in the range 1-10 6 Gy. Its peculiarities are the wide dose range, the high accuracy, the absence fading at room temperature, the possibility of many times repeated measurements as dosemeter accumulates dose, the simplicity of measurements. Because of this performance ESR alanine dosimetry technique can be applied to continuous monitoring radiation doses absorbed by materials on nuclear power stations as well as of dose fields and restoration doses after an accident situation. In order to determine accurately the absorbed dose in an accident on background of accumulated dose for previous period, it is necessary to the utmost increase the accuracy of dosimetry system. For this reason it is necessary to know how the properties of free radicals which formings in irradiated L-alanine are displayed in signal ESR. With the purpose to detect the structure of the free radicals the ESR spectra the L-alanine and L-alanine-d 3 single crystals were studied. The samples were grown by slow evaporation of the saturated aqueous solution. For obtain the L-alanine-d 3 the three-divisible recrystallization in heavy water had been used. The samples were irradiated with 60 Co at room temperature and in liquid nitrogen. The irradiation doses were 10 kGy and dose rate was 8,3 Gy/s. To increase the resolution of the ESR spectra hyperfine structure the second derivative for the absorption curve was registered. The measurements were conducted in X-range at temperatures 77-430 K. (author)

  15. Dose Response of Alanine Detectors Irradiated with Carbon Ion Beams

    DEFF Research Database (Denmark)

    Herrmann, Rochus; Jäkel, Oliver; Palmans, Hugo

    2011-01-01

    Purpose: The dose response of the alanine detector shows a dependence on particle energy and type, when irradiated with ion beams. The purpose of this study is to investigate the response behaviour of the alanine detector in clinical carbon ion beams and compare the results with model predictions......-dose curves deviate from predictions in the peak region, most pronounced at the distal edge of the peak. Conclusions: The used model and its implementation show a good overall agreement for quasi mono energetic measurements. Deviations in depth-dose measurements are mainly attributed to uncertainties...

  16. Soft Interfaces

    International Nuclear Information System (INIS)

    Strzalkowski, Ireneusz

    1997-01-01

    This book presents an extended form of the 1994 Dirac Memorial Lecture delivered by Pierre Gilles de Gennes at Cambridge University. The main task of the presentation is to show the beauty and richness of structural forms and phenomena which are observed at soft interfaces between two media. They are much more complex than forms and phenomena existing in each phase separately. Problems are discussed including both traditional, classical techniques, such as the contact angle in static and dynamic partial wetting, as well as the latest research methodology, like 'environmental' scanning electron microscopes. The book is not a systematic lecture on phenomena but it can be considered as a compact set of essays on topics which particularly fascinate the author. The continuum theory widely used in the book is based on a deep molecular approach. The author is particularly interested in a broad-minded rheology of liquid systems at interfaces with specific emphasis on polymer melts. To study this, the author has developed a special methodology called anemometry near walls. The second main topic presented in the book is the problem of adhesion. Molecular processes, energy transformations and electrostatic interaction are included in an interesting discussion of the many aspects of the principles of adhesion. The third topic concerns welding between two polymer surfaces, such as A/A and A/B interfaces. Of great worth is the presentation of various unsolved, open problems. The kind of topics and brevity of description indicate that this book is intended for a well prepared reader. However, for any reader it will present an interesting picture of how many mysterious processes are acting in the surrounding world and how these phenomena are perceived by a Nobel Laureate, who won that prize mainly for his investigations in this field. (book review)

  17. Stereoselective aminoacylation of a dinucleoside monophosphate by the imidazolides of DL-alanine and N-(tert-butoxycarbonyl)-DL-alanine

    Science.gov (United States)

    Profy, A. T.; Usher, D. A.

    1984-01-01

    The aminoacylation of diinosine monophosphate was studied experimentally. When the acylating agent was the imidazolide of N-(tert-butoxycarbonyl)-DL-alanine, a 40 percent enantiomeric excess of the isomer was incorporated at the 2' site and the positions of equilibrium for the reversible 2'-3' migration reaction differed for the D and L enantiomers. The reactivity of the nucleoside hydroxyl groups was found to decrease on the order 2'(3') less than internal 2' and less than 5', and the extent of the reaction was affected by the concentration of the imidazole buffer. Reaction of IpI with imidazolide of unprotected DL-alanine, by contrast, led to an excess of the D isomer at the internal 2' site. Finally, reaction with the N-carboxy anhydride of DL-alanine occurred without stereoselection. These results are found to be relevant to the study of the evolution of optical chemical activity and the origin of genetically directed protein synthesis.

  18. New Poly(amide-imide)/Nanocomposites Reinforced Silicate Nanoparticles Based on N-pyromellitimido-L-phenyl Alanine Containing Ether Moieties

    Science.gov (United States)

    Faghihi, Khalil; Shabanian, Meisam; Dadfar, Ehsan

    2012-02-01

    A series of Poly(amide-imide)/montmorillonite nanocomposites containing N-pyromellitimido-L-phenyl alanine moiety in the main chain were synthesized by a convenient solution intercalation technique. Poly(amide-imide) (PAI) 5 as a source of polymer matrix was synthesized by the direct polycondensation reaction of N-pyromellitimido-L-phenyl alanine 3 with 4,4'-diamino diphenyl ether 4 in the presence of triphenyl phosphite (TPP), CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP). The resulting nanocomposite films were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The results showed that organo-modified clay was dispersed homogeneously in PAI matrix. TGA indicated an enhancement of thermal stability of new nanocomposites compared with the pure polymer.

  19. Spectrophotometric readout for an alanine dosimeter for food irradiation applications

    International Nuclear Information System (INIS)

    Ebraheem, S.; Beshir, W.B.; Eid, S.; Sobhy, R.; Kovacs, A.

    2003-01-01

    The alanine-electron spin resonance (EPR) readout system is well known as a reference and transfer dosimetry system for the evaluation of high doses in radiation processing. The high cost of an EPR/alanine dosimetry system is a serious handicap for large-scale routine application in irradiation facilities. In this study, the use of a complex produced by dissolving irradiated L-alanine in 1,4-phenyl diammonium dichloride solution was investigated for dosimetry purposes. This complex--having a purple colour--has an increasing absorbance with increasing dose in the range of 1-20 kGy. The applicability of spectrophotometric evaluation was studied by measuring the absorbance intensity of this complex at 360 and 505 nm, respectively. Fluorimetric evaluation was also investigated by measuring the emission of the complex at 435 nm as a function of dose. The present method is easy for routine application. The effect of the dye concentration as well as the suitable amount of irradiated alanine has been studied. With respect to routine application, the stability of the product complex after its formation was also investigated

  20. Dextran Sulfate Sodium Inhibits Alanine Synthesis in Caco-2 Cells

    Directory of Open Access Journals (Sweden)

    Carolyn M. Slupsky

    2011-04-01

    Full Text Available To understand and characterize the pathogenic mechanisms of inflammatory bowel disease, dextran sulfate sodium (DSS has been used to induce acute and chronic colitis in animal models by causing intestinal epithelium damage. The mechanism of action of DSS in producing this outcome is not well understood. In an effort to understand how DSS might impact epithelial cell metabolism, we studied the intestinal epithelial cell line Caco-2 incubated with 1% DSS over 56 hours using 1H NMR spectroscopy. We observed no difference in cell viability as compared to control cultures, and an approximately 1.5-fold increase in IL-6 production upon incubation with 1% DSS. The effect on Caco-2 cell metabolism as measured through changes in the concentration of metabolites in the cell supernatant included a three-fold decrease in the concentration of alanine. Given that the concentrations of other amino acids in the cell culture supernatant were not different between treated and control cultures over 56 hours suggest that DSS inhibits alanine synthesis, specifically alanine aminotransferase, without affecting other key metabolic pathways. The importance of alanine aminotransferase in inflammatory bowel disease is discussed.

  1. Thin layer alanine dosimeter with optical spectrophotometric evaluation

    International Nuclear Information System (INIS)

    Zagorski, Z.P.

    2000-01-01

    Experience in the high dose dosimetry of gamma radiation, gathered in our group from the sixties till now, allows to express the opinion, that techniques applied are adequate to solve problems. It can be confirmed by the fact that 60% of laboratories participating in the international comparison during the duration of the contract obtained satisfactory results. Adaptation of these methods, in particular of the alanine-ESR dosimetry to highly inhomogeneous fields of EB gives poor results, as it has been shown on thin films of the alanine/polymer composite. However, the applications of these films give excellent results if the concentration of the radical CH 3 C·H CO 2 - is measured by diffuse reflection spectrophotometry, which tolerates poor transparency of the composite and is insensitive to the orientation of crystals of alanine in thin films, what is disqualifying the ESR measurements. The development of thin-film dosimeters for EB processing was possible due to new developments in solid state radiation chemistry. The research has revealed some unsolved questions, e.g. of the high temperature coefficient of alanine based dosimeters, of the role of the size of spurs and the necessity to adapt dosimetry to the energy spectrum of electrons, because every type of accelerators differs in that respect. (author)

  2. PGC-1α regulates alanine metabolism in muscle cells.

    Science.gov (United States)

    Hatazawa, Yukino; Qian, Kun; Gong, Da-Wei; Kamei, Yasutomi

    2018-01-01

    The skeletal muscle is the largest organ in the human body, depositing energy as protein/amino acids, which are degraded in catabolic conditions such as fasting. Alanine is synthesized and secreted from the skeletal muscle that is used as substrates of gluconeogenesis in the liver. During fasting, the expression of PGC-1α, a transcriptional coactivator of nuclear receptors, is increased in the liver and regulates gluconeogenesis. In the present study, we observed increased mRNA expression of PGC-1α and alanine aminotransferase 2 (ALT2) in the skeletal muscle during fasting. In C2C12 myoblast cells overexpressing PGC-1α, ALT2 expression was increased concomitant with an increased alanine level in the cells and medium. In addition, PGC-1α, along with nuclear receptor ERR, dose-dependently enhanced the ALT2 promoter activity in reporter assay using C2C12 cells. In the absence of glucose in the culture medium, mRNA levels of PGC-1α and ALT2 increased. Endogenous PGC-1α knockdown in C2C12 cells reduced ALT2 gene expression level, induced by the no-glucose medium. Taken together, in the skeletal muscle, PGC-1α activates ALT2 gene expression, and alanine production may play roles in adaptation to fasting.

  3. High Energy Electron Dosimetry by Alanine/ESR Spectroscopy

    International Nuclear Information System (INIS)

    Chu, Sung Sil

    1989-01-01

    Dosimetry based on electron spin resonance(ESR) analysis of radiation induced free radicals in amino acids is relevant to biological dosimetry applications. Alanine detectors are without walls and are tissue equivalent. Therefore, alanine ESR dosimetry looks promising for use in the therapy level. The dose range of the alanine/ESR dosimetry system can be extended down to l Gy. In a water phantom the absorbed dose of electrons generated by a medical linear accelerator of different initial energies (6-21 MeV) and therapeutic dose levels(1-60 Gy) was measured. Furthermore, depth dose measurements carried out with alanine dosimeters were compared with ionization chamber measurements. As the results, the measured absorbed doses for shallow depth of initial electron energies above 15 MeV were higher by 2-5% than those calculated by nominal energy CE factors. This seems to be caused by low energy scattered beams generated from the scattering foil and electron cones of beam projecting device in medical linear accelerator

  4. Impact of weight reduction program on serum alanine ...

    African Journals Online (AJOL)

    Objective: This study was to examine the correlation between body mass index, serum alanine .... level recorded at least 2 distinct instances at an interval of ... ing exercises, 30 minutes of aerobic exercise training with intensity equal 60-70% of the individual maximum heart .... loric restriction after consuming a high-fat diet.

  5. Two alanine racemase genes in Salmonella typhimurium that differ in structure and function.

    OpenAIRE

    Wasserman, S A; Walsh, C T; Botstein, D

    1983-01-01

    Mutations were isolated in a previously undescribed Salmonella typhimurium gene encoding an alanine racemase essential for utilization of L-alanine as a source of carbon, energy, and nitrogen. This new locus, designated dadB, lies within one kilobase of the D-alanine dehydrogenase locus (dadA), which is also required for alanine catabolism. The dadA and dadB genes are coregulated. Mutants (including insertions) lacking the dadB alanine racemase do not require D-alanine for growth unless a mut...

  6. The unresolved puzzle why alanine extensions cause disease.

    Science.gov (United States)

    Winter, Reno; Liebold, Jens; Schwarz, Elisabeth

    2013-08-01

    The prospective increase in life expectancy will be accompanied by a rise in the number of elderly people who suffer from ill health caused by old age. Many diseases caused by aging are protein misfolding diseases. The molecular mechanisms underlying these disorders receive constant scientific interest. In addition to old age, mutations also cause congenital protein misfolding disorders. Chorea Huntington, one of the most well-known examples, is caused by triplet extensions that can lead to more than 100 glutamines in the N-terminal region of huntingtin, accompanied by huntingtin aggregation. So far, nine disease-associated triplet extensions have also been described for alanine codons. The extensions lead primarily to skeletal malformations. Eight of these proteins represent transcription factors, while the nuclear poly-adenylate binding protein 1, PABPN1, is an RNA binding protein. Additional alanines in PABPN1 lead to the disease oculopharyngeal muscular dystrophy (OPMD). The alanine extension affects the N-terminal domain of the protein, which has been shown to lack tertiary contacts. Biochemical analyses of the N-terminal domain revealed an alanine-dependent fibril formation. However, fibril formation of full-length protein did not recapitulate the findings of the N-terminal domain. Fibril formation of intact PABPN1 was independent of the alanine segment, and the fibrils displayed biochemical properties that were completely different from those of the N-terminal domain. Although intranuclear inclusions have been shown to represent the histochemical hallmark of OPMD, their role in pathogenesis is currently unclear. Several cell culture and animal models have been generated to study the molecular processes involved in OPMD. These studies revealed a number of promising future therapeutic strategies that could one day improve the quality of life for the patients.

  7. Kinetic Interface

    DEFF Research Database (Denmark)

    2009-01-01

    A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises.......A kinetic interface for orientation detection in a video training system is disclosed. The interface includes a balance platform instrumented with inertial motion sensors. The interface engages a participant's sense of balance in training exercises....

  8. Effect of lysine to alanine mutations on the phosphate activation and BPTES inhibition of glutaminase.

    Science.gov (United States)

    McDonald, Charles J; Acheff, Eric; Kennedy, Ryan; Taylor, Lynn; Curthoys, Norman P

    2015-09-01

    The GLS1 gene encodes a mitochondrial glutaminase that is highly expressed in brain, kidney, small intestine and many transformed cells. Recent studies have identified multiple lysine residues in glutaminase that are sites of N-acetylation. Interestingly, these sites are located within either a loop segment that regulates access of glutamine to the active site or the dimer:dimer interface that participates in the phosphate-dependent oligomerization and activation of the enzyme. These two segments also contain the binding sites for bis-2[5-phenylacetamido-1,2,4-thiadiazol-2-yl]ethylsulfide (BPTES), a highly specific and potent uncompetitive inhibitor of this glutaminase. BPTES is also the lead compound for development of novel cancer chemotherapeutic agents. To provide a preliminary assessment of the potential effects of N-acetylation, the corresponding lysine to alanine mutations were constructed in the hGACΔ1 plasmid. The wild type and mutated proteins were purified by Ni(+)-affinity chromatography and their phosphate activation and BPTES inhibition profiles were analyzed. Two of the alanine substitutions in the loop segment (K311A and K328A) and the one in the dimer:dimer interface (K396A) form enzymes that require greater concentrations of phosphate to produce half-maximal activation and exhibit greater sensitivity to BPTES inhibition. By contrast, the K320A mutation results in a glutaminase that exhibits near maximal activity in the absence of phosphate and is not inhibited by BPTES. Thus, lysine N-acetylation may contribute to the acute regulation of glutaminase activity in various tissues and alter the efficacy of BPTES-type inhibitors. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Cooperative scans

    NARCIS (Netherlands)

    M. Zukowski (Marcin); P.A. Boncz (Peter); M.L. Kersten (Martin)

    2004-01-01

    textabstractData mining, information retrieval and other application areas exhibit a query load with multiple concurrent queries touching a large fraction of a relation. This leads to individual query plans based on a table scan or large index scan. The implementation of this access path in most

  10. Assessment of an alanine EPR dosimetry technique with enhanced precision and accuracy

    CERN Document Server

    Hayes, R B; Wieser, A; Romanyukha, A A; Hardy, B L; Barrus, J K

    2000-01-01

    Dose reconstruction in the course of a series of blind tests demonstrated that an accuracy of 10 mGy for low doses and 1% for high doses can be achieved using EPR spectroscopy. This was accomplished using a combination of methodologies including polynomial filtration of the EPR spectrum, dosimeter rotation during scanning, use of an EPR standard fixed into the resonator and subtraction of all nonradiogenic signals. Doses were reconstructed over the range of 0.01-1000 Gy using this compound spectral EPR analysis. This EPR technique, being equally applicable to fractionated doses (such as those delivered during multiple radiotherapy treatments), was verified to exhibit dose reciprocity. Irradiated alanine dosimeters which were stored exhibited compound spectral EPR signal fading of ca 3% over 9 months. All error estimates given in this paper are given at the 1 standard deviation level and unless otherwise specified do not account for uncertainties in source calibration.

  11. Assessment of an alanine EPR dosimetry technique with enhanced precision and accuracy

    International Nuclear Information System (INIS)

    Hayes, Robert B.; Haskell, E.H.; Wieser, Albrecht; Romanyukha, Alexander A.; Hardy, Byron L.; Barrus, Jeffrey K.

    2000-01-01

    Dose reconstruction in the course of a series of blind tests demonstrated that an accuracy of 10 mGy for low doses and 1% for high doses can be achieved using EPR spectroscopy. This was accomplished using a combination of methodologies including polynomial filtration of the EPR spectrum, dosimeter rotation during scanning, use of an EPR standard fixed into the resonator and subtraction of all nonradiogenic signals. Doses were reconstructed over the range of 0.01-1000 Gy using this compound spectral EPR analysis. This EPR technique, being equally applicable to fractionated doses (such as those delivered during multiple radiotherapy treatments), was verified to exhibit dose reciprocity. Irradiated alanine dosimeters which were stored exhibited compound spectral EPR signal fading of ca 3% over 9 months. All error estimates given in this paper are given at the 1 standard deviation level and unless otherwise specified do not account for uncertainties in source calibration

  12. Radionuclide scanning

    International Nuclear Information System (INIS)

    Shapiro, B.

    1986-01-01

    Radionuclide scanning is the production of images of normal and diseased tissues and organs by means of the gamma-ray emissions from radiopharmaceutical agents having specific distributions in the body. The gamma rays are detected at the body surface by a variety of instruments that convert the invisible rays into visible patterns representing the distribution of the radionuclide in the body. The patterns, or images, obtained can be interpreted to provide or to aid diagnoses, to follow the course of disease, and to monitor the management of various illnesses. Scanning is a sensitive technique, but its specificity may be low when interpreted alone. To be used most successfully, radionuclide scanning must be interpreted in conjunction with other techniques, such as bone radiographs with bone scans, chest radiographs with lung scans, and ultrasonic studies with thyroid scans. Interpretation is also enhanced by providing pertinent clinical information because the distribution of radiopharmaceutical agents can be altered by drugs and by various procedures besides physiologic and pathologic conditions. Discussion of the patient with the radionuclide scanning specialist prior to the study and review of the results with that specialist after the study are beneficial

  13. Study on the EPR/dosimetric properties of some substituted alanines

    International Nuclear Information System (INIS)

    Gancheva, Veselka; Sagstuen, Einar; Yordanov, Nicola D.

    2006-01-01

    Polycrystalline phenyl-alanine and perdeuterated l-α-alanine (l-α-alanine-d 4 ) were studied as potential high-energy radiation-sensitive materials (RSM) for solid state/EPR dosimetry. It was found that phenyl-alanine exhibits a linear dose response in the dose region 0.1-17kGy. However, phenyl-alanine is about 10 times less sensitive to γ-irradiation than standard l-α-alanine irradiated at the same doses. Moreover, the EPR response from phenyl-alanine is unstable and, independent of the absorbed dose, decreases by about 50% within 20 days after irradiation upon storage at room temperature. γ-irradiated polycrystalline perdeuterated l-α-alanine (CD 3 CD(NH 2 )COOH) has not previously been studied at room temperature by EPR spectroscopy. The first part of the present analysis was with respect to the structure of the EPR spectrum. By spectrum simulations, the presence of at least two radiation induced free radicals, R 1 =CH 3 C*(H)COOH and R 2 =H 3 N + -C*(CH 3 )COO - , was confirmed very clearly. Both these radicals were suggested previously from EPR and ENDOR studies of standard alanine crystals. The further investigations into the potential use of alanine-d 4 as RSM, after choosing optimal EPR spectrometer settings parameters for this purpose, show that it is ca. two times more sensitive than standard l-α-alanine

  14. 21 CFR 862.1030 - Alanine amino transferase (ALT/SGPT) test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alanine amino transferase (ALT/SGPT) test system... Test Systems § 862.1030 Alanine amino transferase (ALT/SGPT) test system. (a) Identification. An alanine amino transferase (ALT/SGPT) test system is a device intended to measure the activity of the...

  15. 40 CFR 721.520 - Alanine, N-(2-carboxyethyl)-N-alkyl-, salt.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alanine, N-(2-carboxyethyl)-N-alkyl... Specific Chemical Substances § 721.520 Alanine, N-(2-carboxyethyl)-N-alkyl-, salt. (a) Chemical substance... alanine, N-(2-carboxyethyl)-N- alkyl-, salt (P-89-336) is subject to reporting under this section for the...

  16. Alanine/ESR dosimetry system for routine use in radiation processing

    International Nuclear Information System (INIS)

    Kojima, T.; Haruyama, Y.; Tachibana, H.; Tanaka, R.; Okamoto, J.; Hara, H.; Kashiwazaki, S.

    1993-01-01

    A new alanine-polystyrene(PS) dosimeter prepared with simplified molding procedure and an automatic desk-top dose-reader of alanine dosimeter were developed for the purpose of routine use. Combination of these two allows us to apply a reliable alanine/ESR dosimetry system to routine dosimetric process control in industrial gamma radiation processing. (Author)

  17. Alanine-EPR dosimetry system. Why we like it?

    International Nuclear Information System (INIS)

    Stuglik, Z.

    2007-01-01

    To develop a new high-dose dosimeter we should: (1) to find material with radiation effect monotonically (if possible linearly) dependent on an absorbed dose; (2) to investigate its dosimetric characteristics (sensitivity, dose range, repeatability, accuracy, post-effects); (3) to evaluate economical parameters of new method (cost and availability of dosimetric material, cost of analytical instrument and its services); (4) to evaluate operational features of new dosimeter (sensitivity for environmental conditions, time from irradiation to the read-out); (5) to perform a calibration curve, i.e. functional dependence between radiation effect (dosimetric signal) and absorbed dose. On the base of this very stable stable ammonium radical (SAR) generated in crystalline α-alanine was established in the INCT as an alanine-EPR dosimetry system. Presented lecture describes the main features of this dosimeter

  18. Physiological hypercortisolemia increases proteolysis, glutamine, and alanine production

    International Nuclear Information System (INIS)

    Darmaun, D.; Matthews, D.E.; Bier, D.M.

    1988-01-01

    Physiological elevations of plasma cortisol levels, as are encountered in stress and severe trauma, were produced in six normal subjects by infusing them with hydrocortisone for 64 h. Amino acid kinetics were measured in the postabsorptive state using three 4-h infusions of L-[1- 13 C]leucine, L-phenyl[ 2 H 5 ]phenylalanine, L-[2- 15 N]glutamine, and L-[1- 13 C]alanine tracers (1) before, (2) at 12 h, and (3) at 60 h of cortisol infusion. Before and throughout the study, the subjects ate a normal diet of adequate protein and energy intake. The cortisol infusion raised plasma cortisol levels significantly from 10 ± 1 to 32 ± 4 μg/dl, leucine flux from 83 ± 3 to 97 ± 3 μmol·kg -1 ·h -1 , and phenylalanine flux from 34 ± 1 to 39 ± 1 (SE) μmol·kg -1 ·h -1 after 12 h of cortisol infusion. These increases were maintained until the cortisol infusion was terminated. These nearly identical 15% increases in two different essential amino acid appearance rates are reflective of increased whole body protein breakdown. Glutamine flux rose by 12 h of cortisol infusion and remained elevated at the same level at 64 h. The increase in flux was primarily due to a 55% increase in glutamine de novo synthesis. Alanine flux increased with acute hypercortisolemia and increased further at 60 h of cortisol infusion, a result primarily of increased alanine de novo synthesis. Insulin, alanine, and lactate plasma levels responded similarly with significant rises between the acute and chronic periods of cortisol infusion. Thus hypercortisolemia increases both protein breakdown and the turnover of important nonessential amino acids for periods of up to 64 h

  19. A thermodynamic study of La(III)L-alanine complexes

    International Nuclear Information System (INIS)

    Elzawawy, F.M.

    1991-01-01

    The protonation constants of L-alanine and the complex formation constants of its La(III) complexes were determined by potentiometric studies at ionic strengths 0.06, 0.1, and 0.15 mol dm -3 (NaClO 4 ) and at different temperatures 20, 27, and 35 O C. The data together with the derived thermodynamic parameters ΔH O , ΔS O , and ΔG O are reported and discussed. (author)

  20. The Alanine Racemase of Mycobacterium smegmatis Is Essential for Growth in the Absence of d-Alanine▿ †

    Science.gov (United States)

    Milligan, Daniel L.; Tran, Sieu L.; Strych, Ulrich; Cook, Gregory M.; Krause, Kurt L.

    2007-01-01

    Alanine racemase, encoded by the gene alr, is an important enzyme in the synthesis of d-alanine for peptidoglycan biosynthesis. Strains of Mycobacterium smegmatis with a deletion mutation of the alr gene were found to require d-alanine for growth in both rich and minimal media. This indicates that alanine racemase is the only source of d-alanine for cell wall biosynthesis in M. smegmatis and confirms alanine racemase as a viable target gene for antimycobacterial drug development. PMID:17827284

  1. Pancreatic stellate cells support tumour metabolism through autophagic alanine secretion.

    Science.gov (United States)

    Sousa, Cristovão M; Biancur, Douglas E; Wang, Xiaoxu; Halbrook, Christopher J; Sherman, Mara H; Zhang, Li; Kremer, Daniel; Hwang, Rosa F; Witkiewicz, Agnes K; Ying, Haoqiang; Asara, John M; Evans, Ronald M; Cantley, Lewis C; Lyssiotis, Costas A; Kimmelman, Alec C

    2016-08-25

    Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease characterized by an intense fibrotic stromal response and deregulated metabolism. The role of the stroma in PDAC biology is complex and it has been shown to play critical roles that differ depending on the biological context. The stromal reaction also impairs the vasculature, leading to a highly hypoxic, nutrient-poor environment. As such, these tumours must alter how they capture and use nutrients to support their metabolic needs. Here we show that stroma-associated pancreatic stellate cells (PSCs) are critical for PDAC metabolism through the secretion of non-essential amino acids (NEAA). Specifically, we uncover a previously undescribed role for alanine, which outcompetes glucose and glutamine-derived carbon in PDAC to fuel the tricarboxylic acid (TCA) cycle, and thus NEAA and lipid biosynthesis. This shift in fuel source decreases the tumour’s dependence on glucose and serum-derived nutrients, which are limited in the pancreatic tumour microenvironment. Moreover, we demonstrate that alanine secretion by PSCs is dependent on PSC autophagy, a process that is stimulated by cancer cells. Thus, our results demonstrate a novel metabolic interaction between PSCs and cancer cells, in which PSC-derived alanine acts as an alternative carbon source. This finding highlights a previously unappreciated metabolic network within pancreatic tumours in which diverse fuel sources are used to promote growth in an austere tumour microenvironment.

  2. Preparation of α-alanine-3H by the interaction of atomic tritium heated up to 2000 K with a solid alanine target at 77 K

    International Nuclear Information System (INIS)

    Filatov, Eh.S.; Simonov, E.F.; Shishkov, A.V.; Mogil'nikov, V.P.

    1979-01-01

    Absorption of hydrogen by alanine targets, the target behaviour and the yield of α-alanine- 3 H were studied in experiments involving straight passage of H and T atoms from the sourse (2000 K) to the target (77 K) as a function of the exposure time. In the studies with 3 H 2 the radioactivity of the gas phase was decreasing more rapidly than the overall pressure of hydrogen: H 3 H accumulates more rapidly in the gas phase. Alanine decomposition products were identified. The conditions for the studies of α-alanine- 3 H are suggested

  3. Expression, crystallization and preliminary X-ray crystallographic analysis of Xoo0352, d-alanine-d-alanine ligase A, from Xanthomonas oryzae pv. oryzae

    International Nuclear Information System (INIS)

    Doan, Thanh Thi Ngoc; Kim, Jin-Kwang; Kim, Hyesoon; Ahn, Yeh-Jin; Kim, Jeong-Gu; Lee, Byoung-Moo; Kang, Lin-Woo

    2008-01-01

    Xoo0352, which encodes d-alanine-d-alanine ligase A (DdlA), from X. oryzae pv. oryzae was cloned, purified and crystallized. Preliminary X-ray crystallographic analysis of DdlA crystals was performed. Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight (BB), which is one of the most devastating diseases of rice in most rice-growing countries. d-Alanine-d-alanine ligase A (DdlA), coded by the Xoo0352 gene, was expressed, purified and crystallized. DdlA is an enzyme that is involved in d-alanine metabolism and the biosynthesis of an essential bacterial peptidoglycan precursor, in which it catalyzes the formation of d-alanyl-d-alanine from two d-alanines, and is thus an attractive antibacterial drug target against Xoo. The DdlA crystals diffracted to 2.3 Å resolution and belonged to the primitive tetragonal space group P4 3 2 1 2, with unit-cell parameters a = b = 83.0, c = 97.6 Å. There is one molecule in the asymmetric unit, with a corresponding V M of 1.88 Å 3 Da −1 and a solvent content of 34.6%. The initial structure was determined by molecular replacement using d-alanine-d-alanine ligase from Staphylococcus aureus as a template model

  4. Transport of the alpha-amino-mono-carboxylic acid L-alanine by the beta-alanine carrier of the rabbit ileum

    DEFF Research Database (Denmark)

    Andersen, Vibeke; Munck, B G

    1987-01-01

    The proposal that the beta-alanine carrier of the rabbit ileum is a high affinity carrier of the neutral amino acids was examined by means of measurements of influx across the brush border membrane of the intact epithelium using L-alanine as a representative of the neutral amino acids. Confirming...... the proposal, evidence was provided for mutual competitive inhibition between beta-alanine and L-alanine; and it was also demonstrated that a process contributes to the influx of L-alanine, which is characterized by a maximum rate of transport equal to that of beta-alanine and a Kt, which is equal to the Ki...... of L-alanine against the influx of beta-alanine. In the concentration range 0.01 to 0.125 mM the influx of L-alanine was found to be linearly related to the concentration indicating a significant unstirred layer influence on present and previous estimates of the Kt values for influx of amino acids...

  5. Crystal structures of active fully assembled substrate- and product-bound complexes of UDP-N-acetylmuramic acid:L-alanine ligase (MurC) from Haemophilus influenzae.

    Science.gov (United States)

    Mol, Clifford D; Brooun, Alexei; Dougan, Douglas R; Hilgers, Mark T; Tari, Leslie W; Wijnands, Robert A; Knuth, Mark W; McRee, Duncan E; Swanson, Ronald V

    2003-07-01

    UDP-N-acetylmuramic acid:L-alanine ligase (MurC) catalyzes the addition of the first amino acid to the cytoplasmic precursor of the bacterial cell wall peptidoglycan. The crystal structures of Haemophilus influenzae MurC in complex with its substrate UDP-N-acetylmuramic acid (UNAM) and Mg(2+) and of a fully assembled MurC complex with its product UDP-N-acetylmuramoyl-L-alanine (UMA), the nonhydrolyzable ATP analogue AMPPNP, and Mn(2+) have been determined to 1.85- and 1.7-A resolution, respectively. These structures reveal a conserved, three-domain architecture with the binding sites for UNAM and ATP formed at the domain interfaces: the N-terminal domain binds the UDP portion of UNAM, and the central and C-terminal domains form the ATP-binding site, while the C-terminal domain also positions the alanine. An active enzyme structure is thus assembled at the common domain interfaces when all three substrates are bound. The MurC active site clearly shows that the gamma-phosphate of AMPPNP is positioned between two bound metal ions, one of which also binds the reactive UNAM carboxylate, and that the alanine is oriented by interactions with the positively charged side chains of two MurC arginine residues and the negatively charged alanine carboxyl group. These results indicate that significant diversity exists in binding of the UDP moiety of the substrate by MurC and the subsequent ligases in the bacterial cell wall biosynthesis pathway and that alterations in the domain packing and tertiary structure allow the Mur ligases to bind sequentially larger UNAM peptide substrates.

  6. Procedure for preparation of 3-fluor-D-alanine, 2-deutero-3-fluor-D-alanine and 2,3,3-trideutero-3-fluor-D-alanine and their salts

    International Nuclear Information System (INIS)

    Kollonitsch, J.; Kahan, F.M.

    1971-01-01

    Procedures for the preparation of 3-fluor-D-alanine, 2-deutero-3-fluor-D-alanine and 2,3,3-trideutero-3-fluor-D-alanine, and salts of these compounds, are described. These new compounds are useful antibacterial substances not only applicable in the disinfection of pharmaceutical, dental and medical equipment, but also in the treatment of diseases caused by bacteria, and may be administered orally. While 3-fluor-L-alanine metabolises rapidly with toxic results, 3-fluor-D-alanine is much more slowly broken down in vivo and is not harmful in normal doses. Further it has been found that deuteration gives new deutero-analogues which are less subject to metabolic breaking down and still retain the antibacterial strength of the original compound. The in vivo activity is thereby increased and maintained. (JIW)

  7. Analysis of an Alanine/Arginine Mixture by Using TLC/FTIR Technique

    Directory of Open Access Journals (Sweden)

    Jun Liu

    2014-01-01

    Full Text Available We applied TLC/FTIR coupled with mapping technique to analyze an alanine/arginine mixture. Narrow band TLC plates prepared by using AgI as a stationary phase were used to separate alanine and arginine. The distribution of alanine and arginine spots was manifested by a 3D chromatogram. Alanine and arginine can be successfully separated by the narrow band TLC plate. In addition, the FTIR spectra of the separated alanine and arginine spots on the narrow band TLC plate are roughly the same as the corresponding reference IR spectra.

  8. Interface Consistency

    DEFF Research Database (Denmark)

    Staunstrup, Jørgen

    1998-01-01

    This paper proposes that Interface Consistency is an important issue for the development of modular designs. Byproviding a precise specification of component interfaces it becomes possible to check that separately developedcomponents use a common interface in a coherent matter thus avoiding a very...... significant source of design errors. Awide range of interface specifications are possible, the simplest form is a syntactical check of parameter types.However, today it is possible to do more sophisticated forms involving semantic checks....

  9. Scanning table

    CERN Multimedia

    1960-01-01

    Before the invention of wire chambers, particles tracks were analysed on scanning tables like this one. Today, the process is electronic and much faster. Bubble chamber film - currently available - (links can be found below) was used for this analysis of the particle tracks.

  10. Scan Statistics

    CERN Document Server

    Glaz, Joseph

    2009-01-01

    Suitable for graduate students and researchers in applied probability and statistics, as well as for scientists in biology, computer science, pharmaceutical science and medicine, this title brings together a collection of chapters illustrating the depth and diversity of theory, methods and applications in the area of scan statistics.

  11. Interface models

    DEFF Research Database (Denmark)

    Ravn, Anders P.; Staunstrup, Jørgen

    1994-01-01

    This paper proposes a model for specifying interfaces between concurrently executing modules of a computing system. The model does not prescribe a particular type of communication protocol and is aimed at describing interfaces between both software and hardware modules or a combination of the two....... The model describes both functional and timing properties of an interface...

  12. Automatic Ultrasound Scanning

    DEFF Research Database (Denmark)

    Moshavegh, Ramin

    on the user adjustments on the scanner interface to optimize the scan settings. This explains the huge interest in the subject of this PhD project entitled “AUTOMATIC ULTRASOUND SCANNING”. The key goals of the project have been to develop automated techniques to minimize the unnecessary settings...... on the scanners, and to improve the computer-aided diagnosis (CAD) in ultrasound by introducing new quantitative measures. Thus, four major issues concerning automation of the medical ultrasound are addressed in this PhD project. They touch upon gain adjustments in ultrasound, automatic synthetic aperture image...

  13. Pressure-induced phase transformations in L-alanine crystals

    DEFF Research Database (Denmark)

    Olsen, J. Staun; Gerward, Leif; Freire, P.T.C.

    2008-01-01

    Raman scattering and synchrotron X-ray diffraction have been used to investigate the high-pressure behavior of L-alanine. This study has confirmed a structural phase transition observed by Raman scattering at 2.3 GPa and identified it as a change from orthorhombic to tetragonal structure. Another...... phase transformation from tetragonal to monoclinic structure has been observed at about 9 GPa. From the equation of state, the zero-pressure bulk modulus and its pressure derivative have been determined as (31.5 +/- 1.4) GPa and 4.4 +/- 0.4, respectively....

  14. The mechanisms of radical formation in L-α-alanine

    International Nuclear Information System (INIS)

    Bugay, A.A.; Onischuk, V.A.; Petrenko, T.L.; Teslenko, V.V.

    2000-01-01

    Modeling of radical transformations in L-α-alanine after irradiation was performed for isolated radicals and for clusters. Special attention was devoted to the explanation of the experimental results concerning selective proton transfer and behavior of cation-radicals because a unique interpretation of the corresponding experiments is very difficult. Both semi-empirical and ab initio methods were used depending on the size of system under investigation. The results obtained show the usefulness of the computer simulation for processes in rather complex materials used in dosimetry

  15. Porcine alanine transaminase after liver allo-and xenotransplantation

    OpenAIRE

    Ekser, Burcin; Gridelli, Bruno; Cooper, David K.C.

    2012-01-01

    Aspartate transaminase (AST) and alanine transaminase (ALT) are measured following liver transplantation as indicators of hepatocellular injury. During a series of orthotopic liver allo-and xenotransplants, we observed that there was an increase in AST in all cases. The anticipated concomitant rise in ALT did not occur when a wild-type (WT) pig was the source of the liver graft, but did occur when a baboon or a genetically engineered (α1,3-galactosyltransferase gene-knockout [GTKO]) pig was t...

  16. Alanine racemase mutants of Burkholderia pseudomallei and Burkholderia mallei and use of alanine racemase as a non-antibiotic-based selectable marker.

    Directory of Open Access Journals (Sweden)

    Sheryl L W Zajdowicz

    Full Text Available Burkholderia pseudomallei and Burkholderia mallei are category B select agents and must be studied under BSL3 containment in the United States. They are typically resistant to multiple antibiotics, and the antibiotics used to treat B. pseudomallei or B. mallei infections may not be used as selective agents with the corresponding Burkholderia species. Here, we investigated alanine racemase deficient mutants of B. pseudomallei and B. mallei for development of non-antibiotic-based genetic selection methods and for attenuation of virulence. The genome of B. pseudomallei K96243 has two annotated alanine racemase genes (bpsl2179 and bpss0711, and B. mallei ATCC 23344 has one (bma1575. Each of these genes encodes a functional enzyme that can complement the alanine racemase deficiency of Escherichia coli strain ALA1. Herein, we show that B. pseudomallei with in-frame deletions in both bpsl2179 and bpss0711, or B. mallei with an in-frame deletion in bma1575, requires exogenous D-alanine for growth. Introduction of bpsl2179 on a multicopy plasmid into alanine racemase deficient variants of either Burkholderia species eliminated the requirement for D-alanine. During log phase growth without D-alanine, the viable counts of alanine racemase deficient mutants of B. pseudomallei and B. mallei decreased within 2 hours by about 1000-fold and 10-fold, respectively, and no viable bacteria were present at 24 hours. We constructed several genetic tools with bpsl2179 as a selectable genetic marker, and we used them without any antibiotic selection to construct an in-frame ΔflgK mutant in the alanine racemase deficient variant of B. pseudomallei K96243. In murine peritoneal macrophages, wild type B. mallei ATCC 23344 was killed much more rapidly than wild type B. pseudomallei K96243. In addition, the alanine racemase deficient mutant of B. pseudomallei K96243 exhibited attenuation versus its isogenic parental strain with respect to growth and survival in murine

  17. Alanine Racemase Mutants of Burkholderia pseudomallei and Burkholderia mallei and Use of Alanine Racemase as a Non-Antibiotic-Based Selectable Marker

    Science.gov (United States)

    Zajdowicz, Sheryl L. W.; Jones-Carson, Jessica; Vazquez-Torres, Andres; Jobling, Michael G.; Gill, Ronald E.; Holmes, Randall K.

    2011-01-01

    Burkholderia pseudomallei and Burkholderia mallei are category B select agents and must be studied under BSL3 containment in the United States. They are typically resistant to multiple antibiotics, and the antibiotics used to treat B. pseudomallei or B. mallei infections may not be used as selective agents with the corresponding Burkholderia species. Here, we investigated alanine racemase deficient mutants of B. pseudomallei and B. mallei for development of non-antibiotic-based genetic selection methods and for attenuation of virulence. The genome of B. pseudomallei K96243 has two annotated alanine racemase genes (bpsl2179 and bpss0711), and B. mallei ATCC 23344 has one (bma1575). Each of these genes encodes a functional enzyme that can complement the alanine racemase deficiency of Escherichia coli strain ALA1. Herein, we show that B. pseudomallei with in-frame deletions in both bpsl2179 and bpss0711, or B. mallei with an in-frame deletion in bma1575, requires exogenous d-alanine for growth. Introduction of bpsl2179 on a multicopy plasmid into alanine racemase deficient variants of either Burkholderia species eliminated the requirement for d-alanine. During log phase growth without d-alanine, the viable counts of alanine racemase deficient mutants of B. pseudomallei and B. mallei decreased within 2 hours by about 1000-fold and 10-fold, respectively, and no viable bacteria were present at 24 hours. We constructed several genetic tools with bpsl2179 as a selectable genetic marker, and we used them without any antibiotic selection to construct an in-frame ΔflgK mutant in the alanine racemase deficient variant of B. pseudomallei K96243. In murine peritoneal macrophages, wild type B. mallei ATCC 23344 was killed much more rapidly than wild type B. pseudomallei K96243. In addition, the alanine racemase deficient mutant of B. pseudomallei K96243 exhibited attenuation versus its isogenic parental strain with respect to growth and survival in murine peritoneal macrophages

  18. Scanning holograms

    International Nuclear Information System (INIS)

    Natali, S.

    1984-01-01

    This chapter reports on the scanning of 1000 holograms taken in HOBC at CERN. Each hologram is triggered by an interaction in the chamber, the primary particles being pions at 340 GeV/c. The aim of the experiment is the study of charm production. The holograms, recorded on 50 mm film with the ''in line'' technique, can be analyzed by shining a parallel expanded laser beam through the film, obtaining immediately above it the real image of the chamber which can then be scanned and measured with a technique half way between emulsions and bubble chambers. The results indicate that holograms can be analyzed as quickly and reliably as in other visual techniques and that to them is open the same order of magnitude of large scale experiments

  19. Bone scans

    International Nuclear Information System (INIS)

    Hetherington, V.J.

    1989-01-01

    Oftentimes, in managing podiatric complaints, clinical and conventional radiographic techniques are insufficient in determining a patient's problem. This is especially true in the early stages of bone infection. Bone scanning or imaging can provide additional information in the diagnosis of the disorder. However, bone scans are not specific and must be correlated with clinical, radiographic, and laboratory evaluation. In other words, bone scanning does not provide the diagnosis but is an important bit of information aiding in the process of diagnosis. The more useful radionuclides in skeletal imaging are technetium phosphate complexes and gallium citrate. These compounds are administered intravenously and are detected at specific time intervals postinjection by a rectilinear scanner with minification is used and the entire skeleton can be imaged from head to toe. Minification allows visualization of the entire skeleton in a single image. A gamma camera can concentrate on an isolated area. However, it requires multiple views to complete the whole skeletal image. Recent advances have allowed computer augmentation of the data received from radionucleotide imaging. The purpose of this chapter is to present the current radionuclides clinically useful in podiatric patients

  20. Performance effects of acute β-alanine induced paresthesia in competitive cyclists.

    Science.gov (United States)

    Bellinger, Phillip M; Minahan, Clare L

    2016-01-01

    β-alanine is a common ingredient in supplements consumed by athletes. Indeed, athletes may believe that the β-alanine induced paresthesia, experienced shortly after ingestion, is associated with its ergogenic effect despite no scientific mechanism supporting this notion. The present study examined changes in cycling performance under conditions of β-alanine induced paresthesia. Eight competitive cyclists (VO2max = 61.8 ± 4.2 mL·kg·min(-1)) performed three practices, one baseline and four experimental trials. The experimental trials comprised a 1-km cycling time trial under four conditions with varying information (i.e., athlete informed β-alanine or placebo) and supplement content (athlete received β-alanine or placebo) delivered to the cyclist: informed β-alanine/received β-alanine, informed placebo/received β-alanine, informed β-alanine/received placebo and informed placebo/received placebo. Questionnaires were undertaken exploring the cyclists' experience of the effects of the experimental conditions. A possibly likely increase in mean power was associated with conditions in which β-alanine was administered (±95% CL: 2.2% ± 4.0%), but these results were inconclusive for performance enhancement (p = 0.32, effect size = 0.18, smallest worthwhile change = 56% beneficial). A possibly harmful effect was observed when cyclists were correctly informed that they had ingested a placebo (-1.0% ± 1.9%). Questionnaire data suggested that β-alanine ingestion resulted in evident sensory side effects and six cyclists reported placebo effects. Acute ingestion of β-alanine is not associated with improved 1-km TT performance in competitive cyclists. These findings are in contrast to the athlete's "belief" as cyclists reported improved energy and the ability to sustain a higher power output under conditions of β-alanine induced paresthesia.

  1. Use of the entire spectrum of irradiated alanine for dosimetry

    International Nuclear Information System (INIS)

    Dolo, J.M.; Moignau, F.

    2005-01-01

    Alanine is an amino acid commonly used in ESR dosimetry as a reference detector. The classic approach for the measurement of irradiated samples is to determine the amplitude of the central peak of the first derivative spectrum. It is generally considered that this technique represents the best and most reproducible solution for achieving an accurate proportionality between the concentration of free radicals inside the resonant cavity, characterized by the amplitude, and the dose. It is also accepted that this central peak corresponds to the free radical CH 3 .CHCOO - . The hyperfine structure of this radical in the spectrum shows five main peaks with the approximate ratios 1:4:6:4:1 as regards coupling. This paper presents another approach featuring analysis of the entire spectrum: (i) ratios of identified peaks (ii) ratio variation vs time with regard to several parameters affecting fading. These variations in the alanine spectrum are probably correlated with the variation of the concentrations of different free radical species. These variations and their positions in the spectrum are very important constraints that increase the uncertainty of this type of measurement

  2. Electron beam dose measurements with alanine/ESR dosimeter

    International Nuclear Information System (INIS)

    Rodrigues, O. Jr.; Galante, O.L.; Campos, L.L.

    2001-01-01

    When the aminoacid alanine, CH 3 -CH(NH 2 )-COOH, is exposed to radiation field, stable free radicals are produced. The predominant paramagnetic specie found at room temperature is the CH 3 -CH-COOH. Electron Spin Resonance - ESR is a technique used for quantification and analysis of radicals in solid and liquid samples. The evaluation of the amount of produced radicals can be associated with the absorbed dose . The alanine/ESR is an established dosimetry method employed for high doses evaluation, it presents good performance for X-rays, gamma, electrons, and protons radiation detection. The High Doses Dosimetry Laboratory of Ipen developed a dosimetric system based on alanina/ESR that presents good characteristics for use in gamma fields such as: wide dose range from 10 to 10 5 Gy, low fading, low uncertainty (<5%), no dose rate dependence and non-destructive ESR single readout. The detector is encapsulated in a special polyethylene tube that reduces the humidity problems and improves the mechanical resistance. The IPEN dosimeter was investigated for application in electron beam fields dosimetry

  3. Dosimetry of blood irradiation using an alanine/ESR dosimeter

    International Nuclear Information System (INIS)

    Chen, F.; Covas, D.T.; Baffa, O.

    2001-01-01

    A batch of 80 DL-alanine dosimeters was supplied to Hemocentro of the Hospital and Clinics of Faculdade de Medicina de Ribeirao Preto (HC-FMRP) SP, Brazil for the purpose of quality control of the radiation dose delivered to blood bags. The irradiation was made using two (40x40) cm 2 parallel opposed radiation fields each with 80 cm of source to surface distance in the Radiotherapy Section of HC-FMRP with the 60 Co teletherapy unit. The calculated radiation absorbed dose at the center of the box was 20 Gy. The dosimeter readings were performed using a Varian E-4 ESR Spectrometer operating in X-band. For the 80 dosimeters and over the irradiation volume throughout a blood bag, the minimum and maximum doses were 14 and 23 Gy, respectively. The mean dose was (18±2) Gy (1σ), and the coefficient of variability was 11.1%. Alanine dosimeters demonstrated easy handling, good precision and adequate sensitivity for this application

  4. Changes in alanine turnover rate due to nutritional and genetic obesity in the rat.

    Science.gov (United States)

    Yebras, M; Salvadó, J; Arola, L; Remesar, X; Segués, T

    1994-08-01

    The changes in alanine turnover were determined in Zucker rats, which were either genetically obese (fa/fa) or rendered obese by dietary treatment (cafeteria fed). The whole body rate of alanine turnover was higher in genetically obese rats than in rats in which obesity was induced by diet (cafeteria). This is possibly due to variations in the rate of the amino acid incorporation into proteins, since the rate of whole body alanine degradation is the same for both groups. Thus, the different pattern followed by alanine turnover rate in these types of obese animals reflects the differences in the nitrogen economy of these animals, pointing to a higher alanine utilization in the genetically obese animals and a conservative management of alanine in the cafeteria-fed animals.

  5. Eukaryotic beta-alanine synthases are functionally related but have a high degree of structural diversity

    DEFF Research Database (Denmark)

    Gojkovic, Zoran; Sandrini, Michael; Piskur, Jure

    2001-01-01

    no pyrimidine catabolic pathway, it enabled growth on N-carbamyl- beta -alanine as the sole nitrogen source. The D. discoideum and D. melanogaster PYD3 gene products are similar to mammalian beta -alanine synthases. In contrast, the S. kluyveri protein is quite different from these and more similar to bacterial......beta -Alanine synthase (EC 3.5.1.6), which catalyzes the final step of pyrimidine catabolism, has only been characterized in mammals. A Saccharomyces kluyveri pyd3 mutant that is unable to grow on N-carbamy-beta -alanine as the sole nitrogen source and exhibits diminished beta -alanine synthase...... N- carbamyl amidohydrolases. All three beta -alanine synthases are to some degree related to various aspartate transcarbamylases, which catalyze the second step of the de novo pyrimidine biosynthetic pathway. PYD3 expression in yeast seems to be inducible by dihydrouracil and N...

  6. Application of an alanine dosimetry system for industrial irradiation and radiation protection

    International Nuclear Information System (INIS)

    Gohs, U.

    1996-01-01

    This paper reports the application of alanine dosimetry in radiation processing. Continuous checks of the EPR measuring conditions as well as using high-quality alanine dosimeters and consistent technique for dose determination guarantee an accuracy of about ± 3% intermediate dose levels. The alanine dosimetry system was applied for dose mapping measurements during irradiator qualification and performance qualification of different products, routine dosimetry, and special radiation protection applications within the gamma irradiator. (author)

  7. Metabolism of [15N]alanine in the ectomycorrhizal fungus Paxillus involutus

    International Nuclear Information System (INIS)

    Chalot, M.; Finlay, R.D.; Ek, H.; Söderström, B.

    1995-01-01

    Chalot, M., Finlay, R. D., Ek, H., and Söderström, B. 1995. Metabolism of [ 15 N]alanine in the ectomycorrhizal fungus Paxillus involutus. Experimental Mycology 19, 297-304. Alanine metabolism in the ectomycorrhizal fungus Paxillus involutus was investigated using [ 15 N]alanine. Short-term exposure of mycelial discs to [ 15 N]alanine showed that the greatest flow of 15 N was to glutamate and to aspartate. Levels of enrichment were as high as 15-20% for glutamate and 13-18% for aspartate, whereas that of alanine reached 30%. Label was also detected in the amino-N of glutamine and in serine and glycine, although at lower levels. Preincubation of mycelia with aminooxyacetate, an inhibitor of transamination reactions. resulted in complete inhibition of the flow of the label to glutamate, aspartate, and amino-N of glutamine, whereas [ 15 N]alanine rapidly accumulated. This evidence indicates the direct involvement of alanine aminotransferase for translocation of 15 N from alanine to glutamate. Alanine may be a convenient reservoir of both nitrogen and carbon. (author)

  8. L-alanine as a precursor of ethylamine in camellia sinensis

    International Nuclear Information System (INIS)

    Takeo, Tadakazu

    1975-01-01

    After absorption of ammonium nitrogen, nitrogen-deficient Camellia sinensis synthesized theanine following synthesis of glutamic acid and alanine. The rate of incorporation of 14 C from L-alanine U- 14 C into theanine was faster than from acetaldehyde 1-2 14 C. Incorporation of 14 C from L-alanine U- 14 C into the ethylamide of theanine was prevented by adding an excess of ethylamine to the culture solution. Green seedlings converted alanine to ethylamine more rapidly than did etiolated seedlings. (auth.)

  9. Alanine Enhances Aminoglycosides-Induced ROS Production as Revealed by Proteomic Analysis

    Directory of Open Access Journals (Sweden)

    Jin-zhou Ye

    2018-01-01

    Full Text Available Metabolite-enabled killing of antibiotic-resistant pathogens by antibiotics is an attractive strategy to manage antibiotic resistance. Our previous study demonstrated that alanine or/and glucose increased the killing efficacy of kanamycin on antibiotic-resistant bacteria, whose action is through up-regulating TCA cycle, increasing proton motive force and enhancing antibiotic uptake. Despite the fact that alanine altered several metabolic pathways, other mechanisms could be potentially involved in alanine-mediated kanamycin killing of bacteria which remains to be explored. In the present study, we adopted proteomic approach to analyze the proteome changes induced by exogenous alanine. Our results revealed that the expression of three outer membrane proteins was altered and the deletion of nagE and fadL decreased the intracellular kanamycin concentration, implying their possible roles in mediating kanamycin transport. More importantly, the integrated analysis of proteomic and metabolomic data pointed out that alanine metabolism could connect to riboflavin metabolism that provides the source for reactive oxygen species (ROS production. Functional studies confirmed that alanine treatment together with kanamycin could promote ROS production that in turn potentiates the killing of antibiotic-resistant bacteria. Further investigation showed that alanine repressed the transcription of antioxidant-encoding genes, and alanine metabolism to riboflavin metabolism connected with riboflavin metabolism through TCA cycle, glucogenesis pathway and pentose phosphate pathway. Our results suggest a novel mechanism by which alanine facilitates kanamycin killing of antibiotic-resistant bacteria via promoting ROS production.

  10. Beta-alanine and dopamine in the reddish brown scales of Papilio butterflies

    International Nuclear Information System (INIS)

    Umebachi, Yoshishige; Ishizaki, Yumi

    1983-01-01

    (1) Reddish brown scales of the anal eye spot in the hind-wings of P. demoleus and P. machaon have been examined for β-alanine and dopamine. (2) The scales were fractionated into 70% ethanol-soluble fraction, 4% HCl-methanol-soluble fraction, and the residua l scales, and the β-alanine content of each fraction was determined. Most of the β-alanine present in the scales has been found in the residual scales. On acid hydrolysis of the residual scales, the β-alanine has been rather rapidly released, and the hydrolysate has contained a large amount of β-alanine. (3) The protein-bound brown pigment (HCl-ppt fraction), which was extracted with 1 N NaOH and precipitated by being acidified with HCl, has contained a large amount of β-alanine. In most or at least some of the β-alanine, the NH 2 -group has been proved to be free. (4) 14 C-Labelled β-alanine and 14 C-dopamine, which were injected at prepupal or pupal stage, have been incorporated in the highest degree into the residual scales. And the 14 C has been confirmed to be present in the HCl-ppt fraction. (5) All these results indicate that the pigment of the reddish brown scales contains β-alanine and dopamine. (author)

  11. Evolutionary Diversification of Alanine Transaminases in Yeast: Catabolic Specialization and Biosynthetic Redundancy

    Directory of Open Access Journals (Sweden)

    Ximena Escalera-Fanjul

    2017-06-01

    Full Text Available Gene duplication is one of the major evolutionary mechanisms providing raw material for the generation of genes with new or modified functions. The yeast Saccharomyces cerevisiae originated after an allopolyploidization event, which involved mating between two different ancestral yeast species. ScALT1 and ScALT2 codify proteins with 65% identity, which were proposed to be paralogous alanine transaminases. Further analysis of their physiological role showed that while ScALT1 encodes an alanine transaminase which constitutes the main pathway for alanine biosynthesis and the sole pathway for alanine catabolism, ScAlt2 does not display alanine transaminase activity and is not involved in alanine metabolism. Moreover, phylogenetic studies have suggested that ScALT1 and ScALT2 come from each one of the two parental strains which gave rise to the ancestral hybrid. The present work has been aimed to the understanding of the properties of the ancestral type Lacchancea kluyveri LkALT1 and Kluyveromyces lactis KlALT1, alanine transaminases in order to better understand the ScALT1 and ScALT2 evolutionary history. These ancestral -type species were chosen since they harbor ALT1 genes, which are related to ScALT2. Presented results show that, although LkALT1 and KlALT1 constitute ScALT1 orthologous genes, encoding alanine transaminases, both yeasts display LkAlt1 and KlAlt1 independent alanine transaminase activity and additional unidentified alanine biosynthetic and catabolic pathway(s. Furthermore, phenotypic analysis of null mutants uncovered the fact that KlAlt1 and LkAlt1 have an additional role, not related to alanine metabolism but is necessary to achieve wild type growth rate. Our study shows that the ancestral alanine transaminase function has been retained by the ScALT1 encoded enzyme, which has specialized its catabolic character, while losing the alanine independent role observed in the ancestral type enzymes. The fact that ScAlt2 conserves 64

  12. Automation of scanning technique by gamma radiation

    International Nuclear Information System (INIS)

    Aamira, Yahya

    2011-01-01

    The gamma scan technique is a nuclear test allowing the analysis of the internal mechanical properties of distillation columns used in petrochemical industries. Such technique is performed manually. So we propose in this work to automate the gamma scan procedure test by using a PLC. In addition, supervision and data acquisition interfaces are proposed.

  13. Organic interfaces

    NARCIS (Netherlands)

    Poelman, W.A.; Tempelman, E.

    2014-01-01

    This paper deals with the consequences for product designers resulting from the replacement of traditional interfaces by responsive materials. Part 1 presents a theoretical framework regarding a new paradigm for man-machine interfacing. Part 2 provides an analysis of the opportunities offered by new

  14. Interface Realisms

    DEFF Research Database (Denmark)

    Pold, Søren

    2005-01-01

    This article argues for seeing the interface as an important representational and aesthetic form with implications for postmodern culture and digital aesthetics. The interface emphasizes realism due in part to the desire for transparency in Human-Computer Interaction (HCI) and partly...

  15. The Response of Alanine Dosimeters in Thermal Neutron Fields

    DEFF Research Database (Denmark)

    Schmitz, T.; Bassler, Niels; Sharpe, P.

    response of all pellets could be reproduced by calculations within a uncertainty of 5 %. For all experiments three dose components have been separated. A proton dose is generated in the 14N(n,p)14C reaction. Secondary gammas are generated by various (n,γ) reactions, dominated by the 2.2 MeV photon from...... experiments the dosimeters will be exposed to higher neutron energies, which are more typical for BNCT treatments. References: [1] Barth, R.F; 2009: Boron neutron capture therapy at the crossroads: Challenges and opportunities. Applied Radiation and Isotopes 67, 3-6. [2] Rogus, R.D.; Harling, O.K.; Yanch, J.C...... for treatment of liver metastases. Applied Radiation and Isotopes 67, 238-241. [4] Sharpe, P.; Sephtan, J.; 2000: An automated system for the measurement of alanine/EPR dosimeters. Applied Radiation and Isotopes 52, 1185-1188....

  16. Radiolysis of alanine adsorbed in a clay mineral

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Ovando, Ellen Y.; Negron-Mendoza, Alicia [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico (UNAM), Circuito Exterior s/n, Ciudad Universitaria, Apartado Postal 70-543, Deleg. Coyoacan, C.P. 04510 (Mexico)

    2013-07-03

    Optical activity in molecules is a chemical characteristic of living beings. In this work, we examine the hypothesis of the influence of different mineral surfaces on the development of a specific chirality in organic molecules when subjected to conditions simulating the primitive Earth during the period of chemical evolution. By using X-ray diffraction techniques and HPLC/ELSD to analyze aqueous suspensions of amino acids adsorbed on minerals irradiated in different doses with a cobalt-60 gamma source, the experiments attempt to prove the hypothesis that some solid surfaces (like clays and meteorite rocks) may have a concentration capacity and protective role against external sources of ionizing radiation (specifically {gamma}-ray) for some organic compounds (like some amino acids) adsorbed on them. Preliminary results show a slight difference in the adsorption and radiolysis of the D-and L-alanine.

  17. Radiolysis of alanine adsorbed in a clay mineral

    International Nuclear Information System (INIS)

    Aguilar-Ovando, Ellen Y.; Negrón-Mendoza, Alicia

    2013-01-01

    Optical activity in molecules is a chemical characteristic of living beings. In this work, we examine the hypothesis of the influence of different mineral surfaces on the development of a specific chirality in organic molecules when subjected to conditions simulating the primitive Earth during the period of chemical evolution. By using X-ray diffraction techniques and HPLC/ELSD to analyze aqueous suspensions of amino acids adsorbed on minerals irradiated in different doses with a cobalt-60 gamma source, the experiments attempt to prove the hypothesis that some solid surfaces (like clays and meteorite rocks) may have a concentration capacity and protective role against external sources of ionizing radiation (specifically γ-ray) for some organic compounds (like some amino acids) adsorbed on them. Preliminary results show a slight difference in the adsorption and radiolysis of the D-and L-alanine

  18. Elaboration And Study Of Transfer Alanine/ESR Dosemeters

    International Nuclear Information System (INIS)

    Torres G, Luz A.

    1996-01-01

    The dosimetry is the dose measure imparted by the energy from the ionizing radiation to the matter. The dosemeters is the means used for the determination of such a dose. Diverse dosimetric classes exist, this classification depends in essence of the energy involved in the irradiation process and of its application necessity. It is as well as in radiological protection movie dosemeter is used, and TLD, in the calibration of units, as those of cobalt, the ionization cameras are used, in the detection of superficial contamination the accountants Geiger Muller and proportional etc. The transfer dosimeter Alanine/ESR is used, object of the present work, is characterized because after reading the registered dose, the information is conserved and it can be transferred and read in any team of ESR. Likewise the following dose that is imparted will be added to the previous one registered, this indicates that the dosemeters is of integral character. In the spectra taken ESR, it is determined that the integral double or area under the curve of the spectrum ESR is proportional to the concentration of free radicals generated by the radiation ionization and in turn this concentration is proportional to the dose received by the pills; in last, these proportionality relationships take to that the area under the curve of the spectrum main ESR is proportional to the radiation dose received by the alanine dosemeters. This dosemeter seeks to be an economic alternative that it will lend the calibration service that today offers the ionization Cameras or the acrylic red industrial dosemeters

  19. Alanine aminotransferase variants conferring diverse NUE phenotypes in Arabidopsis thaliana.

    Science.gov (United States)

    McAllister, Chandra H; Good, Allen G

    2015-01-01

    Alanine aminotransferase (AlaAT, E.C. 2.6.1.2), is a pyridoxal-5'-phosphate-dependent (PLP) enzyme that catalyzes the reversible transfer of an amino group from alanine to 2-oxoglutarate to produce glutamate and pyruvate, or vice versa. It has been well documented in both greenhouse and field studies that tissue-specific over-expression of AlaAT from barley (Hordeum vulgare, HvAlaAT) results in a significant increase in plant NUE in both canola and rice. While the physical phenotypes associated with over-expression of HvAlaAT have been well characterized, the role this enzyme plays in vivo to create a more N efficient plant remains unknown. Furthermore, the importance of HvAlaAT, in contrast to other AlaAT enzyme homologues in creating this phenotype has not yet been explored. To address the role of AlaAT in NUE, AlaAT variants from diverse sources and different subcellular locations, were expressed in the wild-type Arabidopsis thaliana Col-0 background and alaat1;2 (alaat1-1;alaat2-1) knockout background in various N environments. The analysis and comparison of both the physical and physiological properties of AlaAT over-expressing transgenic plants demonstrated significant differences between plants expressing the different AlaAT enzymes under different external conditions. This analysis indicates that the over-expression of AlaAT variants other than HvAlaAT in crop plants could further increase the NUE phenotype(s) previously observed.

  20. A comparison of three materials used in ESR dosimetry: L-α-alanine, DL-α-alanine and standard bone powder. Response to Co-60 gamma radiation

    International Nuclear Information System (INIS)

    Stuglik, Z.; Sadlo, J.

    1995-01-01

    Three solid state materials: L-α-alanine, DL-α-alanine and standard bone powder were irradiated with gamma analyzed with ESR method. It was stated that the G-value of paramagnetic centres in L-α-alanine is practically the same as in DL-alpha-alanine and about 50 times higher than in non-deproteinized bone powder. The sensitivities of investigated materials are proportional to their G-values if double integrals of ESR signals are chosen as a measure of radiation effects. When first derivatives of ESR absorption bands are used to the construction of dose-response curves (peak-to-peak method) the sensitivities of all investigated materials are comparable. (author). 14 refs, 1 fig., 3 tabs

  1. Efficient L-Alanine Production by a Thermo-Regulated Switch in Escherichia coli.

    Science.gov (United States)

    Zhou, Li; Deng, Can; Cui, Wen-Jing; Liu, Zhong-Mei; Zhou, Zhe-Min

    2016-01-01

    L-Alanine has important applications in food, pharmaceutical and veterinary and is used as a substrate for production of engineered thermoplastics. Microbial fermentation could reduce the production cost and promote the application of L-alanine. However, the presence of L-alanine significantly inhibit cell growth rate and cause a decrease in the ultimate L-alanine productivity. For efficient L-alanine production, a thermo-regulated genetic switch was designed to dynamically control the expression of L-alanine dehydrogenase (alaD) from Geobacillus stearothermophilus on the Escherichia coli B0016-060BC chromosome. The optimal cultivation conditions for the genetically switched alanine production using B0016-060BC were the following: an aerobic growth phase at 33 °C with a 1-h thermo-induction at 42 °C followed by an oxygen-limited phase at 42 °C. In a bioreactor experiment using the scaled-up conditions optimized in a shake flask, B0016-060BC accumulated 50.3 g biomass/100 g glucose during the aerobic growth phase and 96 g alanine/100 g glucose during the oxygen-limited phase, respectively. The L-alanine titer reached 120.8 g/l with higher overall and oxygen-limited volumetric productivities of 3.09 and 4.18 g/l h, respectively, using glucose as the sole carbon source. Efficient cell growth and L-alanine production were reached separately, by switching cultivation temperature. The results revealed the application of a thermo-regulated strategy for heterologous metabolic production and pointed to strategies for improving L-alanine production.

  2. Corrosion inhibition of nickel in H2SO4 solution by alanine

    International Nuclear Information System (INIS)

    Hamed, E.; Abd El-REhim, S.S.; El-Shahat, M.F.; Shaltot, A.M.

    2012-01-01

    Highlights: ► Corrosion of Ni in 1 M H 2 SO 4 in the absence and the presence of alanine. ► Alanine acts as a moderate mixed type inhibitor. ► Physical adsorption of alanine and formation of protective film are on Ni surface. ► Addition of KI improves the inhibition efficiency (synergistic effect). ► EFM technique is in reasonably good agreement with the different techniques used. - Abstract: The effect of alanine, as a safe inhibitor, was studied by measuring the corrosion of Ni in aerated and stagnant 1 M H 2 SO 4 solution (pH ∼0.2). Measurements were performed under various conditions using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and the new electrochemical frequency modulation (EFM) methods. The obtained results showed that the addition of alanine alone gives a moderate inhibition and acts as an anodic-type inhibitor. The inhibition is due to physical adsorption of alanine on the metal surface. The inhibition efficiency enhances with increasing alanine concentration and immersion time but decreases with rise in temperature. The apparent activation energy, E a , is higher in the presence than in the absence of alanine. Addition of I − ions greatly improves the inhibition efficiency of alanine. The synergistic effect is due to enhanced adsorption of alanine cations by chemisorbed I − anions on the metal surface. The results obtained from polarization, EIS and EFM techniques are in good agreement indicating that EFM method can be used successfully for monitoring corrosion rate of Ni in H 2 SO 4 solution with and without alanine.

  3. Microprocessor interfacing

    CERN Document Server

    Vears, R E

    2014-01-01

    Microprocessor Interfacing provides the coverage of the Business and Technician Education Council level NIII unit in Microprocessor Interfacing (syllabus U86/335). Composed of seven chapters, the book explains the foundation in microprocessor interfacing techniques in hardware and software that can be used for problem identification and solving. The book focuses on the 6502, Z80, and 6800/02 microprocessor families. The technique starts with signal conditioning, filtering, and cleaning before the signal can be processed. The signal conversion, from analog to digital or vice versa, is expl

  4. No effect of β-alanine on muscle function and kayak performance

    DEFF Research Database (Denmark)

    Bech, Signe Refsgaard; Nielsen, Tobias Schmidt; Hald, Martin

    2018-01-01

    PURPOSE: It was investigated if β-alanine supplementation counteracts muscular fatigue development or improves athletic performance. METHODS: Elite kayak rowers (10 males and 7 females) were supplemented with either 80 mg/kg body mass/day β-alanine or placebo for 8 weeks. Muscular fatigue...

  5. Degradation of pyrimidines in Saccharomyces kluyveri: transamination of beta-alanine

    DEFF Research Database (Denmark)

    Schnackerz, K D; Andersen, G; Dobritzsch, D

    2008-01-01

    Beta-alanine is an intermediate in the reductive degradation of uracil. Recently we have identified and characterized the Saccharomyces kluyveri PYD4 gene and the corresponding enzyme beta -alanine aminotransferase ((Sk)Pyd4p), highly homologous to eukaryotic gamma-aminobutyrate aminotransferase ...

  6. Regulation of the ald Gene Encoding Alanine Dehydrogenase by AldR in Mycobacterium smegmatis

    Science.gov (United States)

    Jeong, Ji-A; Baek, Eun-Young; Kim, Si Wouk; Choi, Jong-Soon

    2013-01-01

    The regulatory gene aldR was identified 95 bp upstream of the ald gene encoding l-alanine dehydrogenase in Mycobacterium smegmatis. The AldR protein shows sequence similarity to the regulatory proteins of the Lrp/AsnC family. Using an aldR deletion mutant, we demonstrated that AldR serves as both activator and repressor for the regulation of ald gene expression, depending on the presence or absence of l-alanine. The purified AldR protein exists as a homodimer in the absence of l-alanine, while it adopts the quaternary structure of a homohexamer in the presence of l-alanine. The binding affinity of AldR for the ald control region was shown to be increased significantly by l-alanine. Two AldR binding sites (O1 and O2) with the consensus sequence GA-N2-ATC-N2-TC and one putative AldR binding site with the sequence GA-N2-GTT-N2-TC were identified upstream of the ald gene. Alanine and cysteine were demonstrated to be the effector molecules directly involved in the induction of ald expression. The cellular level of l-alanine was shown to be increased in M. smegmatis cells grown under hypoxic conditions, and the hypoxic induction of ald expression appears to be mediated by AldR, which senses the intracellular level of alanine. PMID:23749971

  7. Polymerization of alanine in the presence of a non-swelling montmorillonite

    Science.gov (United States)

    Paecht-Horowitz, M.; Lahav, N.

    1977-01-01

    Alanine, starting from alanine-adenylate, has been polymerized in the presence of non-swelling Al-montmorillonite. The yield of polymerization is much lower than that obtained in the presence of swelling Na-montmorillonite. The possibility that the changing interlayer spacing in Na-montmorillonite might be responsible for its catalytic properties, is discussed.

  8. Application of a Biodegradable Polyesteramide Derived from L-Alanine as Novel Excipient for Controlled Release Matrix Tablets.

    Science.gov (United States)

    Bonillo Martínez, Ana Dora; Galán, Inés Carmen Rodríguez; Bellver, María Victoria Margarit

    2017-11-01

    This pre-formulation study assays the capacity of the polyesteramide PADAS, poly (L-alanine-dodecanediol-L-alanine-sebacic), as an insoluble tablet excipient matrix for prolonged drug release. The flow properties of PADAS were suitable for tableting, and the compressibility of tablets containing exclusively PADAS was evaluated by ESEM observation of the microstructure. The tablets were resistant to crushing and non-friable and they did not undergo disintegration (typical features of an inert matrix). Tablets containing 33.33% sodium diclofenac (DF), ketoprofen (K) or dexketoprofen trometamol (DK-T) as a model drug, in addition with 66.67% of polymer, were formulated, and the absence of interactions between the components was confirmed by differential scanning calorimetry. Dissolution tests showed that PADAS retained DF and K and prolonged drug release, following a Higuchi kinetic. The tablets containing DK-T did not retain the drug sufficiently for prolonged release to be established. Tablets containing DK-T and 66.67, 83.33 or 91.67% PADAS, compressed at 44.48 or 88.96 kN, were elaborated to determine the influence of the polymer amount and of the compression force on DK-T release. Both parameters significantly delayed drug release, except when the proportion of polymer was 91.67%.

  9. Interface Anywhere

    Data.gov (United States)

    National Aeronautics and Space Administration — Current paradigms for crew interfaces to the systems that require control are constrained by decades old technologies which require the crew to be physically near an...

  10. Dependence of alanine gel dosimeter response as a function of photon clinical beams dose rate

    International Nuclear Information System (INIS)

    Silva, Cleber Feijo; Campos, Leticia Lucente

    2013-01-01

    Gel dosimetry is a new area developed by Gore, it is ery useful for application in radiotherapy because using NMR imaging as evaluation technique is possible to evaluate three dimensional absorbed dose distribution. The measure technique is based on difference of ferrous (Fe 2+ ) and ferric (Fe 3+ ) ) ions concentration that can be measured also by spectrophotometry technique. The Alanine gel dosimeter was developed at IPEN. The alanine is an amino acid and tissue equivalent material that presents significant improvement on previous alanine dosimetry systems. The addition of Alanine increases the production of ferric ions in the solution. This work aims to study the dose rate dependence of photon clinical beams radiation on the alanine gel dosimeter optical response, as well as the response repeatability and gel production reproducibility, since this property is very important for characterization and standardization of any dosimeter. (author)

  11. Synthesis and Analysis of Methacryloyl-L-Alanine Methyl Ester using fourier Transform Nuclear Magnetic Resonance

    International Nuclear Information System (INIS)

    Tri Darwinto

    2008-01-01

    Methacryloyl-L-alanine methyl ester was synthesized by reacting methacrylic acid with L-alanine methyl ester hydrochloride in triethylamine at temperature of 90 o C. Hydrogel polymer of poly(methacryloyl-L-alanine methyl ester) was much used for diagnosis and therapy of vascular tumor. The molecular structure methacryloyl-L-alanine methyl ester analyzed by fourier transform nuclear magnetic resonance (FT-NMR) for analyzing of carbon atom ( 13 C) using Distortionless Enhancement by Polarization Transfer (DEPT) measurement mode with coupling as well as without coupling from proton atom ( 1 H). Molecular structure analysis result showed that DEPT FT-NMR measurement mode with coupling as well as without coupling from 1 H was very fast, exact and accurate method for molecular analysis of organic compound especially methacryloyl-L-alanine methyl ester. (author)

  12. Synthesis and GGCT Inhibitory Activity of N-Glutaryl-L-alanine Analogues.

    Science.gov (United States)

    Ii, Hiromi; Yoshiki, Tatsuhiro; Hoshiya, Naoyuki; Uenishi, Jun'ichi

    2016-01-01

    γ-Glutamylcyclotransferase (GGCT) is an important enzyme that cleaves γ-glutamyl-amino acid in the γ-glutamyl cycle to release 5-oxoproline and amino acid. Eighteen N-acyl-L-alanine analogues including eleven new compounds have been synthesized and examined for their inhibitory activity against recombinant human GGCT protein. Simple N-glutaryl-L-alanine was found to be the most potent inhibitor for GGCT. Other N-glutaryl-L-alanine analogues having methyl and dimethyl substituents at the 2-position were moderately effective, while N-(3R-aminoglutary)-L-alanine, the substrate having an (R)-amino group at the 3-position or N-(N-methyl-3-azaglutaryl)-L-alanine, the substrate having an N-methyl substituent on the 3-azaglutaryl carbon, in constract, exhibited excellent inhibition properties.

  13. Preliminary assessment of LiF and alanine detectors for the dosimetry of proton therapy beams

    International Nuclear Information System (INIS)

    Fattibene, P.; Calicchia, A.; De Angelis, C.; Onori, S.; Egger, E.

    1996-01-01

    An experimental intercomparison between the proton response of LiF TLD-100 and alanine detectors is reported. The investigations were performed with LiF chips and alanine pellets in a 62 MeV proton beam at the Paul Scherrer Institut in Villigen (CH). Results were compared with reference dosimetry provided by Markus type parallel plate ionization chamber. The response of the detectors was studied, in a phantom, at different beam penetration depths in pristine and modulated beams. For both alanine and TL detectors, within the experimental uncertainty of the measurements, no significant energy dependence in the response was observed down to the Bragg peak region. The sensitivity of alanine and LiF detectors to protons was measured in the centre of modulated Bragg peak and no significant difference was found with respect to 60 Co. Contrary to LiF, alanine also offers a remarkable tissue equivalence which favours its choice for in-phantom dosimetry. (author)

  14. A new synthesis of [3-11C]pyruvic acid using alanine racemase

    International Nuclear Information System (INIS)

    Ikemoto, M.; Okamoto, E.; Sasaki, M.; Haradahira, T.; Omura, H.; Furuya, Y.; Suzuki, K.; Watanabe, Y.

    1998-01-01

    The synthesis of [3- 11 C]pyruvic acid was attempted by two reaction systems (A: alanine racemase and D-amino acid oxidase, B: alanine racemase and L-alanine dehydrogenase) utilizing a new thermostable enzyme, alanine racemase. Conversion rates from D,L-[3- 11 C]alanine to [3- 11 C]pyruvic acid were almost 100% in both methods. Similar results were obtained with immobilized enzymes packed in a single column. Furthermore, the same column could be used repeatedly without a remarkable decrease of the [3- 11 C]pyruvic acid yield. Various matrices were tested for the immobilizing enzyme, and Aminopropyl-CPG was concluded to be the most suitable since the loss of the enzyme activity was the least in the studied matrices

  15. Uses of polymer-alanine film/ESR dosimeters in dosimetry of ionizing radiation

    International Nuclear Information System (INIS)

    Xie Liqing; Zhang Yinfeng; Dai Jinxian; Lu Ting; Chen Ruyi; Yang Hua

    1993-01-01

    Alanine ESR dosimetry is a reliable method, used in a various fields of ionizing radiation. The polymer-alanine film/ESR dosimeters of 0.3 -0.4 mm thickness were prepared and their dosimetric properties were studied for 60 Co γ photons and 3 - 5 MeV electrons in the dose range from 20 Gy to 100 kGy. The results show that under normal conditions the alanine calibration curves are linear in the dose range from 100 Gy to 10kGy. The dose profiles at the electron radiation field were measured with the film alanine dosimeters. The polymer-alanine film dosimeters were used for ion implantation of 400 keV ion implantor. Their dose response and energy dependence were investigated initially. (Author)

  16. Alanine dosimetry at NPL - the development of a mailed reference dosimetry service at radiotherapy dose levels

    International Nuclear Information System (INIS)

    Sharpe, P.H.G.; Sephton, J.P.

    1999-01-01

    In this paper we describe the work that has been carried out at National Physical Laboratory (NPL) to develop a mailed alanine reference dosimetry service for radiotherapy dose levels. The service is based on alanine/paraffin wax dosimeters produced at NPL. Using a data analysis technique based on spectrum fitting, it has been possible to achieve a precision of dose measurement better than ±0.05 Gy (1σ). A phantom set has been developed for use in high energy photon beams, which enables simultaneous irradiation of alanine dosimeters and ionisation chambers in a well defined geometry. Studies in photon beams of energies between 60 Co and 20 MeV have shown no significant energy dependence (<1%) for alanine relative to dose determination using a graphite calorimeter. Work is underway to extend the service to electron beams, and preliminary results are presented on the direct calibration of alanine in electron beams using a graphite calorimeter. (author)

  17. Thermal decomposition behavior of potassium and sodium jarosite synthesized in the presence of methylamine and alanine

    Energy Technology Data Exchange (ETDEWEB)

    J. Michelle Kotler; Nancy W. Hinman; C. Doc Richardson; Jill R. Scott

    2010-10-01

    Biomolecules, methylamine and alanine, found associated with natural jarosite samples peaked the interest of astrobiologists and planetary geologists. How the biomolecules are associated with jarosite remains unclear although the mechanism could be important for detecting biosignatures in the rock record on Earth and other planets. A series of thermal gravimetric experiments using synthetic K-jarosite and Na-jarosite were conducted to determine if thermal analysis could differentiate physical mixtures of alanine and methylamine with jarosite from samples where the methylamine or alanine was incorporated into the synthesis procedure. Physical mixtures and synthetic experiments with methylamine and alanine could be differentiated from one another and from the standards by thermal analysis for both the K-jarosite and Na-jarosite end-member suites. Changes included shifts in on-set temperatures, total temperature changes from on-set to final, and the presence of indicator peaks for methylamine and alanine in the physical mixture experiments.

  18. Impact of charged amino acid substitution in the transmembrane domain of L-alanine exporter, AlaE, of Escherichia coli on the L-alanine export.

    Science.gov (United States)

    Kim, Seryoung; Ihara, Kohei; Katsube, Satoshi; Ando, Tasuke; Isogai, Emiko; Yoneyama, Hiroshi

    2017-01-01

    The Escherichia coli alaE gene encodes the L-alanine exporter, AlaE, that catalyzes active export of L-alanine using proton electrochemical potential. The transporter comprises only 149 amino acid residues and four predicted transmembrane domains (TMs), which contain three charged amino acid residues. The AlaE-deficient L-alanine non-metabolizing cells (ΔalaE cells) appeared hypersusceptible to L-alanyl-L-alanine showing a minimum inhibitory concentration (MIC) of 2.5 µg/ml for the dipeptide due to a toxic accumulation of L-alanine. To elucidate the mechanism by which AlaE exports L-alanine, we replaced charged amino acid residues in the TMs, glutamic acid-30 (TM-I), arginine-45 (TM-II), and aspartic acid-84 (TM-III) with their respective charge-conserved amino acid or a net neutral cysteine. The ΔalaE cells producing R45K or R45C appeared hypersusceptible to the dipeptide, indicating that arginine-45 is essential for AlaE activity. MIC of the dipeptide in the ΔalaE cells expressing E30D and E30C was 156 µg/ml and >10,000 µg/ml, respectively, thereby suggesting that a negative charge at this position is not essential. The ΔalaE cells expressing D84E or D84C showed an MIC >10,000 and 78 µg/ml, respectively, implying that a negative charge is required at this position. These results were generally consistent with that of the L-alanine accumulation experiments in intact cells. We therefore concluded that charged amino acid residues (R45 and D84) in the AlaE transmembrane domain play a pivotal role in L-alanine export. Replacement of three cysteine residues at C22, C28 (both in TM-I), and C135 (C-terminal region) with alanine showed only a marginal effect on L-alanine export.

  19. Head CT scan

    Science.gov (United States)

    ... scan - orbits; CT scan - sinuses; Computed tomography - cranial; CAT scan - brain ... head size in children Changes in thinking or behavior Fainting Headache, when you have certain other signs ...

  20. Effect of beta-alanine, with and without sodium bicarbonate, on 2000-m rowing performance.

    Science.gov (United States)

    Hobson, Ruth M; Harris, Roger C; Martin, Dan; Smith, Perry; Macklin, Ben; Gualano, Bruno; Sale, Craig

    2013-10-01

    To examine the effect of beta-alanine only and beta-alanine with sodium bicarbonate supplementation on 2,000-m rowing performance. Twenty well-trained rowers (age 23 ± 4 y; height 1.85 ± 0.08 m; body mass 82.5 ± 8.9 kg) were assigned to either a placebo or beta-alanine (6.4 g · d(-1) for 4 weeks) group. A 2,000-m rowing time trial (TT) was performed before supplementation (Baseline) and after 28 and 30 days of supplementation. The post supplementation trials involved supplementation with either maltodextrin or sodium bicarbonate in a double-blind, crossover design, creating four study conditions (placebo with maltodextrin; placebo with sodium bicarbonate; beta-alanine with maltodextrin; beta-alanine with sodium bicarbonate). Blood lactate, pH, bicarbonate, and base excess were measured pre-TT, immediately post-TT and at TT+5 min. Performance data were analyzed using magnitude based inferences. Beta-alanine supplementation was very likely to be beneficial to 2,000-m rowing performance (6.4 ± 8.1 s effect compared with placebo), with the effect of sodium bicarbonate having a likely benefit (3.2 ± 8.8 s). There was a small (1.1 ± 5.6 s) but possibly beneficial additional effect when combining chronic beta-alanine supplementation with acute sodium bicarbonate supplementation compared with chronic beta-alanine supplementation alone. Sodium bicarbonate ingestion led to increases in plasma pH, base excess, bicarbonate, and lactate concentrations. Both chronic beta-alanine and acute sodium bicarbonate supplementation alone had positive effects on 2,000-m rowing performance. The addition of acute sodium bicarbonate to chronic beta-alanine supplementation may further enhance rowing performance.

  1. Prediction of hot spots in protein interfaces using a random forest model with hybrid features.

    Science.gov (United States)

    Wang, Lin; Liu, Zhi-Ping; Zhang, Xiang-Sun; Chen, Luonan

    2012-03-01

    Prediction of hot spots in protein interfaces provides crucial information for the research on protein-protein interaction and drug design. Existing machine learning methods generally judge whether a given residue is likely to be a hot spot by extracting features only from the target residue. However, hot spots usually form a small cluster of residues which are tightly packed together at the center of protein interface. With this in mind, we present a novel method to extract hybrid features which incorporate a wide range of information of the target residue and its spatially neighboring residues, i.e. the nearest contact residue in the other face (mirror-contact residue) and the nearest contact residue in the same face (intra-contact residue). We provide a novel random forest (RF) model to effectively integrate these hybrid features for predicting hot spots in protein interfaces. Our method can achieve accuracy (ACC) of 82.4% and Matthew's correlation coefficient (MCC) of 0.482 in Alanine Scanning Energetics Database, and ACC of 77.6% and MCC of 0.429 in Binding Interface Database. In a comparison study, performance of our RF model exceeds other existing methods, such as Robetta, FOLDEF, KFC, KFC2, MINERVA and HotPoint. Of our hybrid features, three physicochemical features of target residues (mass, polarizability and isoelectric point), the relative side-chain accessible surface area and the average depth index of mirror-contact residues are found to be the main discriminative features in hot spots prediction. We also confirm that hot spots tend to form large contact surface areas between two interacting proteins. Source data and code are available at: http://www.aporc.org/doc/wiki/HotSpot.

  2. Compound-specific nitrogen isotope analysis of D-alanine, L-alanine, and valine: application of diastereomer separation to delta15N and microbial peptidoglycan studies.

    Science.gov (United States)

    Takano, Yoshinori; Chikaraishi, Yoshito; Ogawa, Nanako O; Kitazato, Hiroshi; Ohkouchi, Naohiko

    2009-01-01

    We have developed an analytical method to determine the compound-specific nitrogen isotope compositions of individual amino acid enantiomers using gas chromatography/combustion/isotope ratio mass spectrometry. A novel derivatization of amino acid diastereomers by optically active (R)-(-)-2-butanol or (S)-(+)-2-butanol offers two advantages for nitrogen isotope analysis. First, chromatographic chiral separation can be achieved without the use of chiral stationary-phase columns. Second, the elution order of these compounds on the chromatogram can be switched by a designated esterification reaction. We applied the method to the compound-specific nitrogen isotope analysis of D- and L-alanine in a peptidoglycan derived from the cell walls of cultured bacteria (Firmicutes and Actinobacteria; Enterococcus faecalis, Staphylococcus aureus, Staphylococcus staphylolyticus, Lactobacillus acidophilus, Bacillus subtilis, Micrococcus luteus, and Streptomyces sp.), natural whole bacterial cells (Bacillus subtilis var. natto), (pseudo)-peptidoglycan from archaea (Methanobacterium sp.), and cell wall from eukaryota (Saccharomyces cerevisiae). We observed statistically significant differences in nitrogen isotopic compositions; e.g., delta15N ( per thousand vs air) in Staphylococcus staphylolyticus for d-alanine (19.2 +/- 0.5 per thousand, n = 4) and L-alanine (21.3 +/- 0.8 per thousand, n = 4) and in Bacillus subtilis for D-alanine (6.2 +/- 0.2 per thousand, n = 3) and L-alanine (8.2 +/- 0.4 per thousand, n = 3). These results suggest that enzymatic reaction pathways, including the alanine racemase reaction, produce a nitrogen isotopic difference in amino acid enantiomers, resulting in 15N-depleted D-alanine. This method is expected to facilitate compound-specific nitrogen isotope studies of amino acid stereoisomers.

  3. Preparation of new series of poly(amide-imide) reinforced layer silicate nano composite containing N-trimellitimide-L-alanine

    International Nuclear Information System (INIS)

    Faghihi, K.; Soleimani, M.; Shabanian, M.

    2011-01-01

    A new poly(amide-imide)-montmorillonite series were generated through solution intercalation technique. Cloisite 20A was used as a modified montmorillonite for ample compatibility with the poly(amide-imide) (PAI) matrix. The PAI 5 chains were synthesized by the direct polycondensation reaction of N-trimellitylimido-L-alanine (3) with 4,4'-diamino diphenyl ether (4) in the presence of tryphenyl phosphites (TPP), CaCl 2 , pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nano composite films 5a-5d with (5-20 Wt%) silicate particles were characterized by Ftir spectroscopy, X-ray diffraction and scanning electron microscopy. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nano composites films were investigated by using UV-Vis spectroscopy, thermogravimetric analysis and water uptake measurements. (Author)

  4. Preparation of new series of poly(amide-imide) reinforced layer silicate nano composite containing N-trimellitimide-L-alanine

    Energy Technology Data Exchange (ETDEWEB)

    Faghihi, K.; Soleimani, M. [Polymer Research Laboratory, Department of Chemistry, Faculty of Science, Islamic Azad University, Arak Branch, Arak (Iran, Islamic Republic of); Shabanian, M., E-mail: k-faghihi@araku.ac.ir [Young Researches Club, Islamic Azad University, Arak Branch, Arak (Iran, Islamic Republic of)

    2011-07-01

    A new poly(amide-imide)-montmorillonite series were generated through solution intercalation technique. Cloisite 20A was used as a modified montmorillonite for ample compatibility with the poly(amide-imide) (PAI) matrix. The PAI 5 chains were synthesized by the direct polycondensation reaction of N-trimellitylimido-L-alanine (3) with 4,4'-diamino diphenyl ether (4) in the presence of tryphenyl phosphites (TPP), CaCl{sub 2}, pyridine and N-methyl-2-pyrrolidone (NMP). Morphology and structure of the resulting PAI-nano composite films 5a-5d with (5-20 Wt%) silicate particles were characterized by Ftir spectroscopy, X-ray diffraction and scanning electron microscopy. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nano composites films were investigated by using UV-Vis spectroscopy, thermogravimetric analysis and water uptake measurements. (Author)

  5. Alanine/RPE dosimetry in the process of blood irradiation

    International Nuclear Information System (INIS)

    Chen, F.; Covas, D.T.; Baffa, O.

    2000-01-01

    A set of eighty dosemeters approximately of Dl- alanine was proportioned to the Hemo center of Hospital das Clinicas of Medicine Faculty at Ribeirao Preto (HC-FRMP) in the Sao Paulo University, with the purpose to realize a quality control of the radiation dose supplied to blood bags. These dosemeters were divided in eight groups and irradiated for a two months period.The dosemeters were adhered to the bags and arranged inside of an acrylic box filled water with dimensions: (40x40x20) cm 3 . The box irradiation was made using two fields parallel-opposed of (40x40) cm 2 at 80 cm distance source-surface, in the Radiotherapy Service of HC-FMRP, with a 60 Co teletherapy unit. The irradiation time was sufficient to supply a dose of 20 Gy approximately in the box center. The RPE measures were realized in a Varian E-4 spectrometer operating in X-band. For the total of dosemeters and for the irradiation volume, the minimum and maximum doses were of 14 Gy and 23 Gy respectively. The mean dose was (18±2) Gy (1 σ), and the variability coefficient 11 %. Around 5 % of the bags received a dose under of the recommended limit by the Brazilian legislation and as consequence, the exposure time was increased. (Author)

  6. Alanine synthesis from glyceraldehyde and ammonium ion in aqueous solution

    Science.gov (United States)

    Weber, A. L.

    1985-01-01

    The formation of alanine (ala) form C(14)-glyceraldehyde and ammonium phosphate in the presence or absence of a thiol is reported. At ambient temperature, ala synthesis was six times more rapid in the presence of 3-mercaptopropionic acid than in its absence (0.6 and 0.1 percent, respectively, after 60 days). Similarly, the presence of another thiol, N-acetylcysteinate, increased the production of ala, as well as of lactate. The reaction pathway of thiol-catalyzed synthesis of ala, with the lactic acid formed in a bypath, is suggested. In this, dehydration of glyceraldehyde is followed by the formation of hemithioacetal. In the presence of ammonia, an imine is formed, which eventually yields ala. This pathway is consistent with the observation that the rate ratio of ala/lactate remains constant throughout the process. The fact that the reaction takes place under anaerobic conditions in the presence of H2O and with the low concentrations of simple substrates and catalysts makes it an attractive model prebiotic reaction in the process of molecular evolution.

  7. Porcine alanine transaminase after liver allo-and xenotransplantation.

    Science.gov (United States)

    Ekser, Burcin; Gridelli, Bruno; Cooper, David K C

    2012-01-01

    Aspartate transaminase (AST) and alanine transaminase (ALT) are measured following liver transplantation as indicators of hepatocellular injury. During a series of orthotopic liver allo-and xenotransplants, we observed that there was an increase in AST in all cases. The anticipated concomitant rise in ALT did not occur when a wild-type (WT) pig was the source of the liver graft, but did occur when a baboon or a genetically engineered (α1,3-galactosyltransferase gene-knockout [GTKO]) pig was the source of the graft. We hypothesized that the cience of Galα1,3Gal in GTKO pig livers may render pig hepatocytes similar to human and baboon hepatocytes in their response to hepatocellular injury. Reviewing the literature, after WT pig liver allotransplantation or xenotransplantation, in the majority of reports, although changes in AST were reported, no mention was made of changes in ALT, suggesting that there was no change in ALT. However, Ramirez et al. reported two cases of liver xenotransplants from hCD55 pigs, following which there were increases in both AST and ALT, suggesting that it is not simply the cience of expression of Galα1,3Gal that is the cause. We acknowledge that our observation is based on a small number of experiments, but we believe it is worth recording. © 2012 John Wiley & Sons A/S.

  8. Relationship between hot spot residues and ligand binding hot spots in protein-protein interfaces.

    Science.gov (United States)

    Zerbe, Brandon S; Hall, David R; Vajda, Sandor; Whitty, Adrian; Kozakov, Dima

    2012-08-27

    In the context of protein-protein interactions, the term "hot spot" refers to a residue or cluster of residues that makes a major contribution to the binding free energy, as determined by alanine scanning mutagenesis. In contrast, in pharmaceutical research, a hot spot is a site on a target protein that has high propensity for ligand binding and hence is potentially important for drug discovery. Here we examine the relationship between these two hot spot concepts by comparing alanine scanning data for a set of 15 proteins with results from mapping the protein surfaces for sites that can bind fragment-sized small molecules. We find the two types of hot spots are largely complementary; the residues protruding into hot spot regions identified by computational mapping or experimental fragment screening are almost always themselves hot spot residues as defined by alanine scanning experiments. Conversely, a residue that is found by alanine scanning to contribute little to binding rarely interacts with hot spot regions on the partner protein identified by fragment mapping. In spite of the strong correlation between the two hot spot concepts, they fundamentally differ, however. In particular, while identification of a hot spot by alanine scanning establishes the potential to generate substantial interaction energy with a binding partner, there are additional topological requirements to be a hot spot for small molecule binding. Hence, only a minority of hot spots identified by alanine scanning represent sites that are potentially useful for small inhibitor binding, and it is this subset that is identified by experimental or computational fragment screening.

  9. In Quest of the Alanine R3 Radical: Multivariate EPR Spectral Analyses of X-Irradiated Alanine in the Solid State.

    Science.gov (United States)

    Jåstad, Eirik O; Torheim, Turid; Villeneuve, Kathleen M; Kvaal, Knut; Hole, Eli O; Sagstuen, Einar; Malinen, Eirik; Futsaether, Cecilia M

    2017-09-28

    The amino acid l-α-alanine is the most commonly used material for solid-state electron paramagnetic resonance (EPR) dosimetry, due to the formation of highly stable radicals upon irradiation, with yields proportional to the radiation dose. Two major alanine radical components designated R1 and R2 have previously been uniquely characterized from EPR and electron-nuclear double resonance (ENDOR) studies as well as from quantum chemical calculations. There is also convincing experimental evidence of a third minor radical component R3, and a tentative radical structure has been suggested, even though no well-defined spectral signature has been observed experimentally. In the present study, temperature dependent EPR spectra of X-ray irradiated polycrystalline alanine were analyzed using five multivariate methods in further attempts to understand the composite nature of the alanine dosimeter EPR spectrum. Principal component analysis (PCA), maximum likelihood common factor analysis (MLCFA), independent component analysis (ICA), self-modeling mixture analysis (SMA), and multivariate curve resolution (MCR) were used to extract pure radical spectra and their fractional contributions from the experimental EPR spectra. All methods yielded spectral estimates resembling the established R1 spectrum. Furthermore, SMA and MCR consistently predicted both the established R2 spectrum and the shape of the R3 spectrum. The predicted shape of the R3 spectrum corresponded well with the proposed tentative spectrum derived from spectrum simulations. Thus, results from two independent multivariate data analysis techniques strongly support the previous evidence that three radicals are indeed present in irradiated alanine samples.

  10. Alanine-EPR as a transfer standard dosimetry system for low energy X radiation

    International Nuclear Information System (INIS)

    Khoury, H.J.; Silva, E.J. da; Mehta, K.; Barros, V.S. de; Asfora, V.K.; Guzzo, P.L.; Parker, A.G.

    2015-01-01

    The purpose of this paper is to evaluate the use of alanine-EPR as a transfer standard dosimetry system for low energy X radiation, such as that in RS-2400, which operates in the range from 25 to 150 kV and 2 to 45 mA. Two types of alanine dosimeters were investigated. One is a commercial alanine pellets from Aérial-Centre de Ressources Technologiques, France and one was prepared in our laboratory (LMRI-DEN/UFPE). The EPR spectra of the irradiated dosimeters were recorded in the Nuclear Energy Department of UFPE, using a Bruker EMX10 EPR spectrometer operating in the X-band. The alanine-EPR dosimetry system was calibrated in the range of 20–220 Gy in this X-ray field, against an ionization chamber calibrated at the relevant X-ray energy with traceability to PTB. The results showed that both alanine dosimeters presented a linear dose response the same sensitivity, when the EPR signal was normalized to alanine mass. The total uncertainty in the measured dose was estimated to be about 3%. The results indicate that it is possible to use the alanine-EPR dosimetry system for validation of a low-energy X ray irradiator, such as RS-2400.

  11. Identification and elucidation of in vivo function of two alanine racemases from Pseudomonas putida KT2440.

    Science.gov (United States)

    Duque, Estrella; Daddaoua, Abdelali; Cordero, Baldo F; De la Torre, Jesús; Antonia Molina-Henares, Maria; Ramos, Juan-Luis

    2017-10-01

    The genome of Pseudomonas putida KT2440 contains two open reading frames (ORFs), PP_3722 and PP_5269, that encode proteins with a Pyridoxal phosphate binding motif and a high similarity to alanine racemases. Alanine racemases play a key role in the biosynthesis of D-alanine, a crucial amino acid in the peptidoglycan layer. For these ORFs, we generated single and double mutants and found that inactivation of PP_5269 resulted in D-alanine auxotrophy, while inactivation of PP_3722 did not. Furthermore, as expected, the PP_3722/PP_5269 double mutant was a strict auxotroph for D-alanine. These results indicate that PP_5269 is an alr allele and that it is the essential alanine racemase in P. putida. We observed that the PP_5269 mutant grew very slowly, while the double PP_5269/PP_3722 mutant did not grow at all. This suggests that PP_3722 may replace PP_5269 in vivo. In fact, when the ORF encoding PP_3772 was cloned into a wide host range expression vector, ORF PP_3722 successfully complemented P. putida PP_5269 mutants. We purified both proteins to homogeneity and while they exhibit similar K M values, the V max of PP_5269 is fourfold higher than that of PP_3722. Here, we propose that PP_5269 and PP_3722 encode functional alanine racemases and that these genes be named alr-1 and alr-2 respectively. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Revised mechanism of d-alanine incorporation into cell wall polymers in Gram-positive bacteria

    Science.gov (United States)

    Reichmann, Nathalie T.; Cassona, Carolina Picarra

    2013-01-01

    Teichoic acids (TAs) are important for growth, biofilm formation, adhesion and virulence of Gram-positive bacterial pathogens. The chemical structures of the TAs vary between bacteria, though they typically consist of zwitterionic polymers that are anchored to either the peptidoglycan layer as in the case of wall teichoic acid (WTA) or the cell membrane and named lipoteichoic acid (LTA). The polymers are modified with d-alanines and a lack of this decoration leads to increased susceptibility to cationic antimicrobial peptides. Four proteins, DltA–D, are essential for the incorporation of d-alanines into cell wall polymers and it has been established that DltA transfers d-alanines in the cytoplasm of the cell onto the carrier protein DltC. However, two conflicting models have been proposed for the remainder of the mechanism. Using a cellular protein localization and membrane topology analysis, we show here that DltC does not traverse the membrane and that DltD is anchored to the outside of the cell. These data are in agreement with the originally proposed model for d-alanine incorporation through a process that has been proposed to proceed via a d-alanine undecaprenyl phosphate membrane intermediate. Furthermore, we found that WTA isolated from a Staphylococcus aureus strain lacking LTA contains only a small amount of d-alanine, indicating that LTA has a role, either direct or indirect, in the efficient d-alanine incorporation into WTA in living cells. PMID:23858088

  13. Alanine-ESR dosimeter: application for dosimetry in industrial electron beam accelerator

    International Nuclear Information System (INIS)

    Murali, S.; Venkataramani, R.; Pushparaja; Sarma, K.S.S.; Natarajan, V.; Sastry, M.D.

    2000-01-01

    The feasibility of DL-α-alanine, as ESR dosimeter in powder form, was examined under the conditions of pulse electron accelerator used as an industrial irradiator. The investigations were carried out to examine the following aspects: (i) Alanine-ESR dose response in irradiator characteristics viz. various beam energies, beam currents, product conveying speeds, (ii) linearity of dose response of irradiated alanine signal for suitable range, (iii) dose uniformity of the irradiated samples and (iv) depth dose measurements using alanine powder dosimeters sandwiched between polyethylene layers. Experiments were carried out by varying some of the irradiator parameters at mobile mode of the conveyor (product under movement) and also at stationary mode for different EB energies and pulse rates. For estimation of EB dose, signal intensities of gamma irradiated DL--alanine powder calibrated with Fricke dosimetry have been used. Feasibility of application of alanine ESR dosimeter for low dose measurement down to 350 Gy has been experimentally established. The present studies show that under variable operating conditions of irradiator, alanine ESR dosimetry is suitable for dosimetric applications from low dose (350 Gy) to high dose (53 kgy). (author)

  14. Preparation of alanine and tyrosine functionalized graphene oxide nanoflakes and their modified carbon paste electrodes for the determination of dopamine

    International Nuclear Information System (INIS)

    Kumar, Mohan; Swamy, B.E. Kumara; Asif, M.H. Mohammed; Viswanath, C.C.

    2017-01-01

    Highlights: • The prepared graphene oxide was functionalized by alanine and tyrosine. • The prepared materials were used for sensor for dopamine. • The functionalized graphene oxide modified carbon paste electrodes shows good sensitivity, stability and repeatability. - Abstract: Herein, established the synthesis of graphene oxide (GO) by Hummers Method with addition of KMnO_4 followed by thermal heating at 80 °C. The obtained GO was further functionalized by alanine and tyrosine. The prepared GO, alanine functionalized GO nanoflakes (AGONF) and tyrosine functionalized GO nanoflakes (TGONF) were characterized by spectroscopic technique using energy-dispersive spectroscopy (EDS), quantitatively by scanning electron microscopy (SEM) and structural studies along with interlayer distance verified through X-ray diffraction technique. Afterwards, the prepared AGONF and TGONF were used as the modifier for the carbon paste electrode (CPE). The electrochemical behavior of the AGONF and TGONF modified carbon paste electrodes (MCPEs) towards dopamine (DA) in phosphate buffer solution (PBS) were examined by cyclic voltammetric (CV) technique and the obtained consequences showed good electrocatalytic activity of MCPEs by increasing the redox peak current with a lower potential difference compared to the bare CPE (BCPE). The AGONF and TGONF MCPEs were further used for the optimization studies. From the pH studies, it was found that the equal number of proton and electron transfer reaction involved in both the modified electrodes. The scan rate studies demonstrate the adsorption controlled electrode process at AGONF MCPE and diffusion controlled at TGONF MCPE. The oxidation peak current increased linearly with two concentration interval of DA at a range of 2–7 μM and 10–30 μM in presence of PBS (pH 7.4) at MCPEs and the limit of detection (LOD) were found to be 0.84 μM and 0.96 μM for first interval DA concentration range (2–7 μM) at AGONF and TGONF MCPE. The

  15. Preparation of alanine and tyrosine functionalized graphene oxide nanoflakes and their modified carbon paste electrodes for the determination of dopamine

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Mohan [Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Shankaraghatta, 577 451, Shimoga, Karnataka (India); Swamy, B.E. Kumara, E-mail: kumaraswamy21@yahoo.com [Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Shankaraghatta, 577 451, Shimoga, Karnataka (India); Asif, M.H. Mohammed [Nanoscience and Technology, Kuvempu University, Shankaraghatta, 577451, Shimoga, Karnataka (India); Viswanath, C.C. [Department of P.G. Studies and Research in Industrial Chemistry, Kuvempu University, Shankaraghatta, 577 451, Shimoga, Karnataka (India)

    2017-03-31

    Highlights: • The prepared graphene oxide was functionalized by alanine and tyrosine. • The prepared materials were used for sensor for dopamine. • The functionalized graphene oxide modified carbon paste electrodes shows good sensitivity, stability and repeatability. - Abstract: Herein, established the synthesis of graphene oxide (GO) by Hummers Method with addition of KMnO{sub 4} followed by thermal heating at 80 °C. The obtained GO was further functionalized by alanine and tyrosine. The prepared GO, alanine functionalized GO nanoflakes (AGONF) and tyrosine functionalized GO nanoflakes (TGONF) were characterized by spectroscopic technique using energy-dispersive spectroscopy (EDS), quantitatively by scanning electron microscopy (SEM) and structural studies along with interlayer distance verified through X-ray diffraction technique. Afterwards, the prepared AGONF and TGONF were used as the modifier for the carbon paste electrode (CPE). The electrochemical behavior of the AGONF and TGONF modified carbon paste electrodes (MCPEs) towards dopamine (DA) in phosphate buffer solution (PBS) were examined by cyclic voltammetric (CV) technique and the obtained consequences showed good electrocatalytic activity of MCPEs by increasing the redox peak current with a lower potential difference compared to the bare CPE (BCPE). The AGONF and TGONF MCPEs were further used for the optimization studies. From the pH studies, it was found that the equal number of proton and electron transfer reaction involved in both the modified electrodes. The scan rate studies demonstrate the adsorption controlled electrode process at AGONF MCPE and diffusion controlled at TGONF MCPE. The oxidation peak current increased linearly with two concentration interval of DA at a range of 2–7 μM and 10–30 μM in presence of PBS (pH 7.4) at MCPEs and the limit of detection (LOD) were found to be 0.84 μM and 0.96 μM for first interval DA concentration range (2–7 μM) at AGONF and TGONF MCPE

  16. Designing Interfaces

    CERN Document Server

    Tidwell, Jenifer

    2010-01-01

    Despite all of the UI toolkits available today, it's still not easy to design good application interfaces. This bestselling book is one of the few reliable sources to help you navigate through the maze of design options. By capturing UI best practices and reusable ideas as design patterns, Designing Interfaces provides solutions to common design problems that you can tailor to the situation at hand. This updated edition includes patterns for mobile apps and social media, as well as web applications and desktop software. Each pattern contains full-color examples and practical design advice th

  17. Importance of intrahepatic mechanisms to gluconeogenesis from alanine during exercise and recovery

    International Nuclear Information System (INIS)

    Wasserman, D.H.; Williams, P.E.; Lacy, D.B.; Green, D.R.; Cherrington, A.D.

    1988-01-01

    These studies were performed to assess the importance of intrahepatic mechanisms to gluconeogenesis in the dog during 150 min of treadmill exercise and 90 min of recovery. Sampling catheters were implanted in an artery and portal and hepatic veins 16 days before experimentation. Infusions of [U- 14 C]alanine, [3- 3 H]glucose, and indocyanine green were used to assess gluconeogenesis. During exercise, a decline in arterial and portal vein plasma alanine and in hepatic blood flow led to a decrease in hepatic alanine delivery. During recovery, hepatic blood flow was restored to basal, causing an increase in hepatic alanine delivery beyond exercise rates but still below resting rates. Hepatic fractional alanine extraction increased from 0.26 +/- 0.02 at rest to 0.64 +/- 0.03 during exercise and remained elevated during recovery. Net hepatic alanine uptake was 2.5 +/- 0.2 mumol.kg-1.min-1 at rest and remained unchanged during exercise but was increased during recovery. The conversion rate of [ 14 C]alanine to glucose had increased by 248 +/- 38% by 150 min of exercise and had increased further during recovery. The efficiency with which alanine was channeled into glucose in the liver was accelerated to a rate of 338 +/- 55% above basal by 150 min of exercise but declined slightly during recovery. In conclusion, 1) gluconeogenesis from alanine is accelerated during exercise, due to an increase in the hepatic fractional extraction of the amino acid and through intrahepatic mechanisms that more efficiently channel it into glucose

  18. d-Alanine metabolism is essential for growth and biofilm formation of Streptococcus mutans.

    Science.gov (United States)

    Qiu, W; Zheng, X; Wei, Y; Zhou, X; Zhang, K; Wang, S; Cheng, L; Li, Y; Ren, B; Xu, X; Li, Y; Li, M

    2016-10-01

    Part of the d-alanine (d-Ala) metabolic pathway in bacteria involves the conversion of l-alanine to d-Ala by alanine racemase and the formation of d-alanyl-d-alanine by d-alanine-d-alanine ligase, the product of which is involved in cell wall peptidoglycan synthesis. At present, drugs that target the metabolic pathway of d-Ala are already in clinical use - e.g. d-cycloserine (DCS) is used as an antibiotic against Mycobacterium tuberculosis. Streptococcus mutans is the main cariogenic bacterium in the oral cavity. Its d-Ala metabolism-associated enzymes alanine racemase and d-alanine-d-alanine ligase are encoded by the genes smu.1834 and smu.599, respectively, which may be potential targets for inhibitors. In this study, the addition of DCS blocked the d-Ala metabolic pathway in S. mutans, leading to bacterial cell wall defects, significant inhibition of bacterial growth and biofilm formation, and reductions in extracellular polysaccharide production and bacterial adhesion. However, the exogenous addition of d-Ala could reverse the inhibitory effect of DCS. Through the means of drug regulation, our study demonstrated, for the first time, the importance of d-Ala metabolism in the survival and biofilm formation of S. mutans. If the growth of S. mutans can be specifically inhibited by designing drugs that target d-Ala metabolism, then this may serve as a potential new treatment for dental caries. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  19. Sensitivity comparison of two L-alanine doped blends to different photon energies

    International Nuclear Information System (INIS)

    Chen, Felipe; Vega Ramirez, Jose; Nicolucci, Patricia; Baffa, Oswaldo

    2008-01-01

    Full text: Blends of L-alanine (85% weight proportion) with KI (10%) and with PbI 2 (10%), these last two compounds acting as dopants, and with PVA (5%) acting as binder, were prepared in water at 80 C degrees. A blend of pure L-alanine (95%) with PVA (5%) was also prepared. The three blends were irradiated with photon beams of different energies (120 kV, 60 Co and 10 MV) with a unique dose of 30 Gy to compare their sensitivities for those three energies. EPR spectra of the three irradiated blends were recorded in a K-Band spectrometer (24 GHz) taking aliquots of about 4 mg for each blend. The energy sensitivity of a blend was defined as the peak-to-peak amplitude of its EPR spectrum central line. For the 60 Co energy (1.25 MeV) the blends presented practically the same sensitivity indicating that the presence of the dopants does not affect the sensitivity of L-alanine. For 10 MV X-rays there was an increment (around 20% - 30 %) in sensitivity for the two L-alanine doped blends compared with the pure L-alanine blend (not doped). In the case of 120 kV X-rays, the blends ala+KI and ala+PbI 2 showed an increment of 10 and 20 times, respectively, more sensitivity than the pure L-alanine blend. It is concluded that the dopants KI and PbI 2 produce a great enhance of the L-alanine sensitivity to low-energy photons. For the same dopant's content (10%) in the blend, PbI 2 showed a better performance. These results encourage us to try to enhance the sensitivity of L-alanine even more increasing the dopant's content in the blend. Application of these L-alanine doped blends in the dosimetry in diagnostic radiology could be possible. (author)

  20. Mitochondrial defects associated with β-alanine toxicity: relevance to hyper-beta-alaninemia

    Science.gov (United States)

    Shetewy, Aza; Shimada-Takaura, Kayoko; Warner, Danielle; Jong, Chian Ju; Mehdi, Abu-Bakr Al; Alexeyev, Mikhail; Takahashi, Kyoko; Schaffer, Stephen W.

    2016-01-01

    Hyper-beta-alaninemia is a rare metabolic condition that results in elevated plasma and urinary β-alanine levels and is characterized by neurotoxicity, hypotonia, and respiratory distress. It has been proposed that at least some of the symptoms are caused by oxidative stress; however, only limited information is available on the mechanism of reactive oxygen species generation. The present study examines the hypothesis that β-alanine reduces cellular levels of taurine, which are required for normal respiratory chain function; cellular taurine depletion is known to reduce respiratory function and elevate mitochondrial superoxide generation. To test the taurine hypothesis, isolated neonatal rat cardiomyocytes and mouse embryonic fibroblasts were incubated with medium lacking or containing β-alanine. β-alanine treatment led to mitochondrial superoxide accumulation in conjunction with a decrease in oxygen consumption. The defect in β-alanine-mediated respiratory function was detected in permeabilized cells exposed to glutamate/malate but not in cells utilizing succinate, suggesting that β-alanine leads to impaired complex I activity. Taurine treatment limited mitochondrial superoxide generation, supporting a role for taurine in maintaining complex I activity. Also affected by taurine is mitochondrial morphology, as β-alanine-treated fibroblasts undergo fragmentation, a sign of unhealthy mitochondria that is reversed by taurine treatment. If left unaltered, β-alanine-treated fibroblasts also undergo mitochondrial apoptosis, as evidenced by activation of caspases 3 and 9 and the initiation of the mitochondrial permeability transition. Together, these data show that β-alanine mediates changes that reduce ATP generation and enhance oxidative stress, factors that contribute to heart failure. PMID:27023909

  1. Serum alanine aminotransferase levels, hematocrit rate and body weight correlations before and after hemodialysis session

    Directory of Open Access Journals (Sweden)

    Edmundo Pessoa Lopes

    2009-01-01

    Full Text Available PURPOSE: To evaluate alanine aminotransferase levels before and after a hemodialysis session and to correlate these values with the hematocrit rate and weight loss during hemodialysis. PATIENTS AND METHODS: The serum alanine aminotransferase levels, hematocrit rate and body weight were measured and correlated before and after a single hemodialysis session for 146 patients with chronic renal failure. An receiver operating characteristic (ROC curve for the serum alanine aminotransferase levels collected before and after hemodialysis was plotted to identify hepatitis C virus-infected patients. RESULTS: The mean weight loss of the 146 patients during hemodialysis was 5.3% (p < 0.001. The mean alanine aminotransferase levels before and after hemodialysis were 18.8 and 23.9 IU/, respectively, denoting a significant 28.1% increase. An equally significant increase of 16.4% in the hematocrit rate also occurred after hemodialysis. The weight loss was inversely correlated with the rise in both the alanine aminotransferase level (r = 0.3; p < 0.001 and hematocrit rate (r = 0.5; p < 0.001. A direct correlation was found between the rise in alanine aminotransferase levels and the hematocrit during the hemodialysis session (r = 0.4; p < 0.001. Based on the ROC curve, the upper limit of the normal alanine aminotransferase level should be reduced by 40% relative to the upper limit of normal if the blood samples are collected before the hemodialysis session or by 60% if blood samples are collected after the session. CONCLUSION: In the present study, significant elevations in the serum alanine aminotransferase levels and hematocrit rates occurred in parallel to a reduction in body weight after the hemodialysis session. These findings suggest that one of the factors for low alanine aminotransferase levels prior to hemodialysis could be hemodilution in patients with chronic renal failure.

  2. Knockout of the alanine racemase gene in Lactobacillus plantarum results in septation defects and cell wall perforation

    NARCIS (Netherlands)

    Palumbo, E.; Favier, C.F.; Deghorain, M.; Cocconcelli, P.S.; Grangette, C.; Mercenier, A.M.E.; Vaughan, E.E.; Hols, P.

    2004-01-01

    A stable mutant of Lactobacillus plantarum deficient in alanine racemase (Alr) was constructed by two successive homologous recombination steps. When the mutant was supplemented with D-alanine, growth and viability were unaffected. Surprisingly, deprivation Of D-alanine during exponential growth did

  3. Characterization of the l-alanine exporter AlaE of Escherichia coli and its potential role in protecting cells from a toxic-level accumulation of l-alanine and its derivatives.

    Science.gov (United States)

    Kim, Seryoung; Ihara, Kohei; Katsube, Satoshi; Hori, Hatsuhiro; Ando, Tasuke; Isogai, Emiko; Yoneyama, Hiroshi

    2015-08-01

    We previously reported that the alaE gene of Escherichia coli encodes the l-alanine exporter AlaE. The objective of this study was to elucidate the mechanism of the AlaE exporter. The minimum inhibitory concentration of l-alanine and l-alanyl-l-alanine in alaE-deficient l-alanine-nonmetabolizing cells MLA301ΔalaE was 4- and >4000-fold lower, respectively, than in the alaE-positive parent cells MLA301, suggesting that AlaE functions as an efflux pump to avoid a toxic-level accumulation of intracellular l-alanine and its derivatives. Furthermore, the growth of the alaE-deficient mutant derived from the l-alanine-metabolizing strain was strongly inhibited in the presence of a physiological level of l-alanyl-l-alanine. Intact MLA301ΔalaE and MLA301ΔalaE/pAlaE cells producing plasmid-borne AlaE, accumulated approximately 200% and 50%, respectively, of the [(3) H]l-alanine detected in MLA301 cells, suggesting that AlaE exports l-alanine. When 200 mmol/L l-alanine-loaded inverted membrane vesicles prepared from MLA301ΔalaE/pAlaE were placed in a solution containing 200 mmol/L or 0.34 μmol/L l-alanine, energy-dependent [(3) H]l-alanine accumulation occurred under either condition. This energy-dependent uphill accumulation of [(3) H]l-alanine was strongly inhibited in the presence of carbonyl cyanide m-chlorophenylhydrazone but not by dicyclohexylcarbodiimide, suggesting that the AlaE-mediated l-alanine extrusion was driven by proton motive force. Based on these results, physiological roles of the l-alanine exporter are discussed. © 2015 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  4. Brain alanine formation as an ammonia-scavenging pathway during hyperammonemia

    DEFF Research Database (Denmark)

    Dadsetan, Sherry; Kukolj, Eva; Bak, Lasse Kristoffer

    2013-01-01

    (MSO) enhances incorporation of (15)NH4(+) in alanine during acute hyperammonemia. We observed a fourfold increased amount of (15)NH4 incorporation in brain alanine in rats treated with MSO. Furthermore, co-cultures of neurons and astrocytes exposed to (15)NH4Cl in the absence or presence of MSO...... demonstrated a dose-dependent incorporation of (15)NH4 into alanine together with increased (15)N incorporation in glutamate. These findings provide evidence that ammonia is detoxified by the concerted action of GDH and ALAT both in vivo and in vitro, a mechanism that is accelerated in the presence of MSO...

  5. Effect of the ionizing radiation on alanine solution for a dosimeter application

    International Nuclear Information System (INIS)

    Abdessamad, Nour El Houda

    2007-01-01

    The amino acid alanine is well known as a dosimetric detector material for high level dosimetry. Its application is based on the formation of radicals by ionising radiation. In this study the effect of several parameters such as: the ionising radiation, the concentration, the dose on the pH, conductivity and the oscillotitrometric answer of L a lanine solution was investigated. The results show that there is a significant production of new species. The formation of these species increases upon increasing dose. The comparison between the repeatability of the used techniques led us to choose of the system alanine/pH and the alanine/conductivity as the most adapted. (Author)

  6. A thin alanine-polyethylene film dosimetry system with diffuse reflection spectrophotometric evaluation

    International Nuclear Information System (INIS)

    Zagorski, Z.P.; Rafalski, A.

    1995-01-01

    Characteristics of a new alanine dosimeter in the shape of a thin film, with the measurement of optical absorption of the CH 3 CHCOO - radical is described. That type of dosimeter, ALA/DRS (for diffuse reflection spectrophotometry) is compared, to an alanine dosimeter with EPR evaluation (ALA/EPR for short). In many respects the simple ALA/DRS version, as the alanine-polyethylene composite is superior. The paper shows the importance of the new experimental approach to free radical research in solid state radiation chemistry. (author). 7 refs., 3 figs

  7. Hydrogen bonds in crystalline d-alanine: diffraction and spectroscopic evidence for differences between enantiomers

    Directory of Open Access Journals (Sweden)

    Ezequiel A. Belo

    2018-01-01

    Full Text Available Enantiomeric amino acids have specific physiological functions in complex biological systems. Systematic studies focusing on the solid-state properties of d-amino acids are, however, still limited. To shed light on this field, structural and spectroscopic studies of d-alanine using neutron powder diffraction, polarized Raman scattering and ab initio calculations of harmonic vibrational frequencies were carried out. Clear changes in the number of vibrational modes are observed as a function of temperature, which can be directly connected to variations of the N—D bond lengths. These results reveal dissimilarities in the structural properties of d-alanine compared with l-alanine.

  8. Mouse manipulation through single-switch scanning.

    Science.gov (United States)

    Blackstien-Adler, Susie; Shein, Fraser; Quintal, Janet; Birch, Shae; Weiss, Patrice L Tamar

    2004-01-01

    Given the current extensive reliance on the graphical user interface, independent access to computer software requires that users be able to manipulate a pointing device of some type (e.g., mouse, trackball) or be able to emulate a mouse by some other means (e.g., scanning). The purpose of the present study was to identify one or more optimal single-switch scanning mouse emulation strategies. Four alternative scanning strategies (continuous Cartesian, discrete Cartesian, rotational, and hybrid quadrant/continuous Cartesian) were selected for testing based on current market availability as well as on theoretical considerations of their potential speed and accuracy. Each strategy was evaluated using a repeated measures study design by means of a test program that permitted mouse emulation via any one of four scanning strategies in a motivating environment; response speed and accuracy could be automatically recorded and considered in view of the motor, cognitive, and perceptual demands of each scanning strategy. Ten individuals whose disabilities required them to operate a computer via single-switch scanning participated in the study. Results indicated that Cartesian scanning was the preferred and most effective scanning strategy. There were no significant differences between results from the Continuous Cartesian and Discrete Cartesian scanning strategies. Rotational scanning was quite slow with respect to the other strategies, although it was equally accurate. Hybrid Quadrant scanning improved access time but at the cost of fewer correct selections. These results demonstrated the importance of testing and comparing alternate single-switch scanning strategies.

  9. Interface unit

    NARCIS (Netherlands)

    Keyson, D.V.; Freudenthal, A.; De Hoogh, M.P.A.; Dekoven, E.A.M.

    2001-01-01

    The invention relates to an interface unit comprising at least a display unit for communication with a user, which is designed for being coupled with a control unit for at least one or more parameters in a living or working environment, such as the temperature setting in a house, which control unit

  10. In vivo dosimetry with L-alpha-alanine

    Energy Technology Data Exchange (ETDEWEB)

    Boey, R; Van Der Velden, K [Industriele Hogeschool van het Gemeenschapsonderwijs Limburg, Hasselt (Belgium); Schaeken, B [Algemeen Ziekenhuis Middelheim, Antwerp (Belgium). Dept. of Radiotherapy

    1995-12-01

    When organic substances are irradiated, stable electrons can be formed. The concentration of these electrons is detected via electron paramagnetic resonance (EPR), a non-destructive form of dosimetry. L-alpha-alanine is extremely suited as a detector because of its high stability and high yield of unpaired electrons. With an EMS 104 spectrometer, we measure the peak-to-peak value of the first derivate of the resonance-spectrum. This value is proportional to the concentration of unpaired electrons and therefore with the absorbed dose. Prior to the in vivo measurements in teletherapy, a calibration curve had to be established. This clearly showed a linear relationship between the EPR-signal and the absorbed dose, except for very low dose where precision was low (20% 1 sd). This indicates that the background signal of the dosimeter is strongly orientation dependent. For this reason it was decided to use pre-irradiated detectors. A number of in vivo measurements has been performed. It was found that the error propagation plays a major role in the calculation of the measured absorbed dose, in the range 1 Gy-6 Gy. Contrary to in vivo measurements in brachytherapy, where higher doses are measured, large uncertainties (30% 1 sd) on the entry dose calculations were observed. For this reason, it is recommended to use a statistical method of reducing this standard deviation to an acceptable level. The proposed method, consisting of 2 detectors and the usage of weight coefficients on our standard deviations, gave promising results. However, theoretical calculations and in vivo measurements show that this method is still not satisfactory to reduce the uncertainty to an acceptable standard in clinical situations.

  11. Interface superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gariglio, S., E-mail: stefano.gariglio@unige.ch [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland); Gabay, M. [Laboratoire de Physique des Solides, Bat 510, Université Paris-Sud 11, Centre d’Orsay, 91405 Orsay Cedex (France); Mannhart, J. [Max Planck Institute for Solid State Research, 70569 Stuttgart (Germany); Triscone, J.-M. [DQMP, Université de Genève, 24 Quai E.-Ansermet, CH-1211 Genève (Switzerland)

    2015-07-15

    Highlights: • We discuss interfacial superconductivity, a field boosted by the discovery of the superconducting interface between LaAlO. • This system allows the electric field control and the on/off switching of the superconducting state. • We compare superconductivity at the interface and in bulk doped SrTiO. • We discuss the role of the interfacially induced Rashba type spin–orbit. • We briefly discuss superconductivity in cuprates, in electrical double layer transistor field effect experiments. • Recent observations of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3} are presented. - Abstract: Low dimensional superconducting systems have been the subject of numerous studies for many years. In this article, we focus our attention on interfacial superconductivity, a field that has been boosted by the discovery of superconductivity at the interface between the two band insulators LaAlO{sub 3} and SrTiO{sub 3}. We explore the properties of this amazing system that allows the electric field control and on/off switching of superconductivity. We discuss the similarities and differences between bulk doped SrTiO{sub 3} and the interface system and the possible role of the interfacially induced Rashba type spin–orbit. We also, more briefly, discuss interface superconductivity in cuprates, in electrical double layer transistor field effect experiments, and the recent observation of a high T{sub c} in a monolayer of FeSe deposited on SrTiO{sub 3}.

  12. Inducible l-Alanine Exporter Encoded by the Novel Gene ygaW (alaE) in Escherichia coli ▿

    Science.gov (United States)

    Hori, Hatsuhiro; Yoneyama, Hiroshi; Tobe, Ryuta; Ando, Tasuke; Isogai, Emiko; Katsumata, Ryoichi

    2011-01-01

    We previously isolated a mutant hypersensitive to l-alanyl-l-alanine from a non-l-alanine-metabolizing Escherichia coli strain and found that it lacked an inducible l-alanine export system. Consequently, this mutant showed a significant accumulation of intracellular l-alanine and a reduction in the l-alanine export rate compared to the parent strain. When the mutant was used as a host to clone a gene(s) that complements the dipeptide-hypersensitive phenotype, two uncharacterized genes, ygaW and ytfF, and two characterized genes, yddG and yeaS, were identified. Overexpression of each gene in the mutant resulted in a decrease in the intracellular l-alanine level and enhancement of the l-alanine export rate in the presence of the dipeptide, suggesting that their products function as exporters of l-alanine. Since ygaW exhibited the most striking impact on both the intra- and the extracellular l-alanine levels among the four genes identified, we disrupted the ygaW gene in the non-l-alanine-metabolizing strain. The resulting isogenic mutant showed the same intra- and extracellular l-alanine levels as observed in the dipeptide-hypersensitive mutant obtained by chemical mutagenesis. When each gene was overexpressed in the wild-type strain, which does not intrinsically excrete alanine, only the ygaW gene conferred on the cells the ability to excrete alanine. In addition, expression of the ygaW gene was induced in the presence of the dipeptide. On the basis of these results, we concluded that YgaW is likely to be the physiologically most relevant exporter for l-alanine in E. coli and proposed that the gene be redesignated alaE for alanine export. PMID:21531828

  13. Feasibility study of entrance and exit dose measurements at the contra lateral breast with alanine/electron spin resonance dosimetry in volumetric modulated radiotherapy of breast cancer

    Science.gov (United States)

    Wagner, Daniela M.; Hüttenrauch, Petra; Anton, Mathias; von Voigts-Rhetz, Philip; Zink, Klemens; Wolff, Hendrik A.

    2017-07-01

    The Physikalisch-Technische Bundesanstalt has established a secondary standard measurement system for the dose to water, D W, based on alanine/ESR (Anton et al 2013 Phys. Med. Biol. 58 3259-82). The aim of this study was to test the established measurement system for the out-of-field measurements of inpatients with breast cancer. A set of five alanine pellets were affixed to the skin of each patient at the contra lateral breast beginning at the sternum and extending over the mammilla to the distal surface. During 28 fractions with 2.2 Gy per fraction, the accumulated dose was measured in four patients. A cone beam computer tomography (CBCT) scan was generated for setup purposes before every treatment. The reference CT dataset was registered rigidly and deformably to the CBCT dataset for 28 fractions. To take the actual alanine pellet position into account, the dose distribution was calculated for every fraction using the Acuros XB algorithm. The results of the ESR measurements were compared to the calculated doses. The maximum dose measured at the sternum was 19.9 Gy  ±  0.4 Gy, decreasing to 6.8 Gy  ±  0.2 Gy at the mammilla and 4.5 Gy  ±  0.1 Gy at the distal surface of the contra lateral breast. The absolute differences between the calculated and measured doses ranged from  -1.9 Gy to 0.9 Gy. No systematic error could be seen. It was possible to achieve a combined standard uncertainty of 1.63% for D W  =  5 Gy for the measured dose. The alanine/ESR method is feasible for in vivo measurements.

  14. Determination of the carbon, hydrogen and nitrogen contents of alanine and their uncertainties using the certified reference material L-alanine (NMIJ CRM 6011-a).

    Science.gov (United States)

    Itoh, Nobuyasu; Sato, Ayako; Yamazaki, Taichi; Numata, Masahiko; Takatsu, Akiko

    2013-01-01

    The carbon, hydrogen, and nitrogen (CHN) contents of alanine and their uncertainties were estimated using a CHN analyzer and the certified reference material (CRM) L-alanine. The CHN contents and their uncertainties, as measured using the single-point calibration method, were 40.36 ± 0.20% for C, 7.86 ± 0.13% for H, and 15.66 ± 0.09% for N; the results obtained using the bracket calibration method were also comparable. The method described in this study is reasonable, convenient, and meets the general requirement of having uncertainties ≤ 0.4%.

  15. Implementation of an alanine dosimetry service; Puesta en marcha de un servicio de dosimetria de alanima

    Energy Technology Data Exchange (ETDEWEB)

    Gago Arias, A.; Nunez Pelaez, N.; Peteiro Vilaseco, E.; Gomez Rodriguez, F.; Gonzalez Castano, D. M.

    2011-07-01

    This work facing the implementation of an alanine dosimetry service, linked to the installation of Co{sub 6}0 Radio physics Laboratory (LP) and Paramagnetic Resonance Service of the University of Santiago de Compostela (USC).

  16. Influence of convulsants on rat brain activities of alanine aminotransferase and aspartate aminotransferase

    Czech Academy of Sciences Publication Activity Database

    Netopilová, M.; Haugvicová, Renata; Kubová, Hana; Dršata, J.; Mareš, Pavel

    2001-01-01

    Roč. 26, č. 12 (2001), s. 1285-1291 ISSN 0364-3190 Institutional research plan: CEZ:AV0Z5011922 Keywords : alanine aminotransferase * aspartale aminotransferase Subject RIV: FH - Neurology Impact factor: 1.638, year: 2001

  17. Different β-alanine dimeric forms in trifluoromethanesulfonic acid salts. XRD and vibrational studies

    Science.gov (United States)

    Wołoszyn, Łukasz; Ilczyszyn, Maria M.

    2018-03-01

    Two new crystalline salts: β-alaninium trifluoromethanesulfonate (β-AlaOTf) and bis(β-alanine) trifluoromethanesulfonate (β-2AlaOTf) were obtained. The former one contains diprotonated β-alanine dimer, the latter one monoprotonated β-alanine dimer. Both compounds were studied by single crystal XRD, vibrational (IR and Raman) spectroscopy and calorimetric method. The quantum-mechanical calculations (DFT/B3LYP/6-311 ++G(2d,2p)) for the diprotonated dimer were carried out. The β-AlaOTf salt crystallizes in the P 1 bar space group of triclinic system (Z = 2), the β-2AlaOTf in the P21/m space group of monoclinic system (Z = 2). The vibrational data for the studied compounds are discussed in relation to their crystal structure, and provide insight into the character of hydrogen bonds and β-alanine protonation. The studied crystals do not exhibit phase transitions in the solid state.

  18. Titration of Alanine Monitored by NMR Spectroscopy: A Biochemistry Laboratory Experiment

    Science.gov (United States)

    Waller, Francis J.; And Others

    1977-01-01

    The experiment described here involves simultaneous monitoring of pH and NMR chemical shifts during an aqueous titration of alpha- and beta-alanine. This experiment is designed for use in an undergraduate biochemistry course. (MR)

  19. Dosimetric calibration of humidity chamber inside the 60Co-PANBIT irradiator using alanine ESR dosimeter

    International Nuclear Information System (INIS)

    Murali, S.; Venkataramani, R.; Pushparaja; Natarajan, V.; Sastry, M.D.; Bora, J.S.; Venkatacharyulu, K.

    1998-01-01

    In the present work the suitability of the electron spin resonance (ESR) technique, using DL - α - alanine sample is examined. It is well documented that radiation induced free radicals in alanine give strong ESR spectrum which can be used for dosimetry purposes. The aspects that are relevant to the present work are: (I) stability of the radicals in temperature and humidity conditions in which the experiments were carried out; (II) linearity at high doses; and (III) establishing the utility of alanine ESR dosimeter by cross checking the dose values with more established dosimeters. The details of these investigations are presented and it is shown that alanine ESR dosimeter will meet all the required conditions satisfactorily

  20. Preparation of alanine/ESR dosimeter using different binder of polymer blend

    International Nuclear Information System (INIS)

    Razzak, M.T.; Sudiro, Sutjipto; Sudradjat, Adjat; Waskito, Ashar; Djamili, M.F.

    1995-01-01

    Different composition of polymer blend of low density polyethylene (PE) and polystyrene (PS) have been studied to be used as a binder for the preparation of Alanine/ESR dosimeter. The polymer binder and Alanine powder were blended in Laboplastomil Mixer at 140 o C and then it was pressed into a plastic film of 0.50 mm thickness. The film was cut into sample size of 250 mm x 2.5 mm and irradiated by gamma rays from a cobalt-60 source at different dose and dose rate. It was found that a blend of Alanine, PS and PE in composition of 60:30:10 is appropriate to prepare the Alanine/ESR dosimeter. (author)

  1. EPR of gamma-irradiated polycrystalline alanine-in-glass dosimeter

    International Nuclear Information System (INIS)

    Al-Karmi, Anan M.; Morsy, M.A.

    2008-01-01

    This study attempts to overcome some of the reported discrepancies in alanine-EPR reproducibility that may be related to alanine dosimeter preparation and/or EPR spectrometer settings. The dosimeters were prepared by packing pure polycrystalline L-α-alanine directly as supplied by the manufacturer in glass tubes. This dosimeter production scheme avoids any possible contribution to the EPR signal from a binding material. The dosimeters were irradiated with gamma ray to low-dose ranges typical for medical therapy (0-20 Gy). Special attention has been paid to the study of minimum detectable dose, measurement repeatability and reproducibility, and post-irradiation stability. The dosimeter exhibited a linear dose response in the dose range from 0.1 to 20 Gy. These positive properties favor the polycrystalline alanine-in-glass tube as a radiation dosimeter

  2. Role of L-alanine for redox self-sufficient amination of alcohols.

    Science.gov (United States)

    Klatte, Stephanie; Wendisch, Volker F

    2015-01-23

    In white biotechnology biocatalysis represents a key technology for chemical functionalization of non-natural compounds. The plasmid-born overproduction of an alcohol dehydrogenase, an L-alanine-dependent transaminase and an alanine dehydrogenase allows for redox self-sufficient amination of alcohols in whole cell biotransformation. Here, conditions to optimize the whole cell biocatalyst presented in (Bioorg Med Chem 22:5578-5585, 2014), and the role of L-alanine for efficient amine functionalization of 1,10-decanediol to 1,10-diaminodecane were analyzed. The enzymes of the cascade for amine functionalization of alcohols were characterized in vitro to find optimal conditions for an efficient process. Transaminase from Chromobacterium violaceum, TaCv, showed three-fold higher catalytic efficiency than transaminase from Vibrio fluvialis, TaVf, and improved production at 37°C. At 42°C, TaCv was more active, which matched thermostable alcohol dehydrogenase and alanine dehydrogenase and improved the 1,10-diaminodecane production rate four-fold. To study the role of L-alanine in the whole cell biotransformation, the L-alanine concentration was varied and 1,10.diaminodecane formation tested with constant 10 mM 1,10- decanediol and 100 mM NH4Cl. Only 5.6% diamine product were observed without added L-alanine. L-alanine concentrations equimolar to that of the alcohol enabled for 94% product formation but higher L-alanine concentrations allowed for 100% product formation. L-alanine was consumed by the E. coli biocatalyst, presumably due to pyruvate catabolism since up to 16 mM acetate accumulated. Biotransformation employing E. coli strain YYC202/pTrc99a-ald-adh-ta Cv, which is unable to catabolize pyruvate, resulted in conversion with a selectivity of 42 mol-%. Biotransformation with E. coli strains only lacking pyruvate oxidase PoxB showed similar reduced amination of 1,10-decanediol indicating that oxidative decarboxylation of pyruvate to acetate by PoxB is primarily

  3. ESR/Alanine {gamma}-dosimetry in the 10-30 Gy range

    Energy Technology Data Exchange (ETDEWEB)

    Fainstein, C. E-mail: cfainstein@cab.cnea.gov.ar; Winkler, E.; Saravi, M

    2000-05-15

    We report Alanine Dosimeter preparation, procedures for using the ESR/Dosimetry method, and the resulting calibration curve for {gamma}-irradiation in the range from 10-30 Gy. We use calibration curve to measure the irradiation dose in {gamma}-irradiation of human blood, as required in Blood Transfusion Therapy. The ESR/Alanine results are compared against those obtained using the thermoluminescent dosimetry (TLD) method.

  4. Synthesis of racemic 2-deutero-3-fluoro-alanine and its salts, and intermediates therefor

    International Nuclear Information System (INIS)

    1975-01-01

    The racemates of 2-deutero-3-fluoro-alanine and its salts are prepared by reductive amination of 3-fluoro-pyruvic acid, its hydrate or salts thereof, via the intermediate 2-imino-3-fluoro propionic acid salt, using alkali metal borodeuterides as reducing agents. The racemates thus obtained are valuable in the production of the corresponding 2-deutero-3-fluoro-D-alanine, and its pharmacologically acceptable salts, and derivatives thereof, which are potent antibacterial agents

  5. The influence of measurement and storage conditions on alanine ESR dosimeters

    International Nuclear Information System (INIS)

    Alexandre, A.C.

    1992-01-01

    Alanine has several desirable properties as an ESR dosemeter e.g. tissue equivalence, low fading and an approximately linear response for doses up to 10 kGy. This work reports on a simple system to produce the alanine dosemeter, the signal intensity for a range of doses and energies, and the effect of the air humidity and the spectrometer settings on the ESR signal. (Author)

  6. Contribution of liver and skeletal muscle to alanine and lactate metabolism in humans

    International Nuclear Information System (INIS)

    Consoli, A.; Nurjhan, N.; Reilly, J.J. Jr.; Bier, D.M.; Gerich, J.E.

    1990-01-01

    To quantitate alanine and lactate gluconeogenesis in postabsorptive humans and to test the hypothesis that muscle is the principal source of these precursors, we infused normal volunteers with [3-14C]lactate, [3-13C]alanine, and [6-3H]glucose and calculated alanine and lactate incorporation into plasma glucose corrected for tricarboxylic acid cycle carbon exchange, the systemic appearance of these substrates, and their forearm fractional extraction, uptake, and release. Forearm alanine and lactate fractional extraction averaged 37 +/- 3 and 27 +/- 2%, respectively; muscle alanine release (2.94 +/- 0.27 mumol.kg body wt-1.min-1) accounted for approximately 70% of its systemic appearance (4.18 +/- 0.31 mumol.kg body wt-1.min-1); muscle lactate release (5.51 +/- 0.42 mumol.kg body wt-1.min-1) accounted for approximately 40% of its systemic appearance (12.66 +/- 0.77 mumol.kg body wt-1.min-1); muscle alanine and lactate uptake (1.60 +/- 0.7 and 3.29 +/- 0.36 mumol.kg body wt-1.min-1, respectively) accounted for approximately 30% of their overall disappearance from plasma, whereas alanine and lactate incorporation into plasma glucose (1.83 +/- 0.20 and 4.24 +/- 0.44 mumol.kg body wt-1.min-1, respectively) accounted for approximately 50% of their disappearance from plasma. We therefore conclude that muscle is the major source of plasma alanine and lactate in postabsorptive humans and that factors regulating their release from muscle may thus exert an important influence on hepatic gluconeogenesis

  7. A Clostridium difficile alanine racemase affects spore germination and accommodates serine as a substrate.

    Science.gov (United States)

    Shrestha, Ritu; Lockless, Steve W; Sorg, Joseph A

    2017-06-23

    Clostridium difficile has become one of the most common bacterial pathogens in hospital-acquired infections in the United States. Although C. difficile is strictly anaerobic, it survives in aerobic environments and transmits between hosts via spores. C. difficile spore germination is triggered in response to certain bile acids and glycine. Although glycine is the most effective co-germinant, other amino acids can substitute with varying efficiencies. Of these, l-alanine is an effective co-germinant and is also a germinant for most bacterial spores. Many endospore-forming bacteria embed alanine racemases into their spore coats, and these enzymes are thought to convert the l-alanine germinant into d-alanine, a spore germination inhibitor. Although the C. difficile Alr2 racemase is the sixth most highly expressed gene during C. difficile spore formation, a previous study reported that Alr2 has little to no role in germination of C. difficile spores in rich medium. Here, we hypothesized that Alr2 could affect C. difficile l-alanine-induced spore germination in a defined medium. We found that alr2 mutant spores more readily germinate in response to l-alanine as a co-germinant. Surprisingly, d-alanine also functioned as a co-germinant. Moreover, we found that Alr2 could interconvert l- and d-serine and that Alr2 bound to l- and d-serine with ∼2-fold weaker affinity to that of l- and d-alanine. Finally, we demonstrate that l- and d-serine are also co-germinants for C. difficile spores. These results suggest that C. difficile spores can respond to a diverse set of amino acid co-germinants and reveal that Alr2 can accommodate serine as a substrate. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  8. SU-E-T-643: Pure Alanine Dosimeter for Verification Dosimetry in IMRT

    International Nuclear Information System (INIS)

    Al-Karmi, Anan M.; Zraiqat, Fadi

    2015-01-01

    Purpose: The objective of this study was evaluation of accuracy of pure alanine dosimeters measuring intensity-modulated radiation therapy (IMRT) dose distributions in a thorax phantom. Methods: Alanine dosimeters were prepared in the form of 110 mg pure L-α-alanine powder filled into clear tissue-equivalent polymethylmethacrylate (PMMA) plastic tubes with the dimensions 25 mm length, 3 mm inner diameter, and 1 mm wall thickness. A dose-response calibration curve was established for the alanine by placing the dosimeters at 1.5 cm depth in a 30×30×30 cm 3 solid water phantom and then irradiating on a linac with 6 MV photon beam at 10×10 cm 2 field size to doses ranging from 1 to 5 Gy. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the absorbed dose in alanine. An IMRT treatment plan was designed for a commercial heterogeneous CIRS thorax phantom and the dose values were calculated at three different points located in tissue, lung, and bone equivalent materials. A set of dose measurements was carried out to compare measured and calculated dose values by placing the alanine dosimeters at those selected locations inside the thorax phantom and delivering the IMRT to the phantom. Results: The alanine dose measurements and the IMRT plan dose calculations were found to be in agreement within ±2%. Specifically, the deviations were −0.5%, 1.3%, and −1.7% for tissue, lung, and bone; respectively. The slightly large deviations observed for lung and bone may be attributed to tissue inhomogeneity, steep dose gradients in these regions, and uncontrollable changes in spectrometer conditions. Conclusion: The results described herein confirmed that pure alanine dosimeter was suitable for in-phantom dosimetry of IMRT beams because of its high sensitivity and acceptable accuracy. This makes the dosimeter a promising option for quality control of the therapeutic beams, complementing the commonly used ionization chambers, TLDs, and films

  9. Use of a range scaling method to determine alanine/water stopping power ratios

    International Nuclear Information System (INIS)

    McEwen, M.R.; Sephton, J.P.; Sharpe, P.H.G.; Shipley, D.R.

    2003-01-01

    A phantom composed of alanine dosimeter material has been constructed and depth-dose measurements made in a 10 MeV electron beam. The results have demonstrated the feasibility of using relative depth-dose measurements to determine stopping power ratios in materials of dosimetric interest. Experimental stopping power ratios for alanine dosimeter material and water agreed with the data of ICRU Report 37 within the uncertainty of the experiment (±1.2% at a 95% confidence level)

  10. Amorphous track predictions in ‘libamtrack’ for alanine relative effectiveness in ion beams

    DEFF Research Database (Denmark)

    Herrmann, Rochus; Greilich, Steffen; Grzanka, Leszek

    2011-01-01

    and simple dose response, the alanine detector can help to study fundamental assumptions and accuracy in amorphous track modelling. The libamtrack project enabled recently to directly compare various flavours of ATMs. We therefore present here the potential of predictions for alanine from two libamtrack ATMs...... transport and stopping powers hinders a thorough interpretation of the deviation found and stress the necessity for a broader data base at lower particle energies....

  11. Interface learning

    DEFF Research Database (Denmark)

    Thorhauge, Sally

    2014-01-01

    "Interface learning - New goals for museum and upper secondary school collaboration" investigates and analyzes the learning that takes place when museums and upper secondary schools in Denmark work together in local partnerships to develop and carry out school-related, museum-based coursework...... for students. The research focuses on the learning that the students experience in the interface of the two learning environments: The formal learning environment of the upper secondary school and the informal learning environment of the museum. Focus is also on the learning that the teachers and museum...... professionals experience as a result of their collaboration. The dissertation demonstrates how a given partnership’s collaboration affects the students’ learning experiences when they are doing the coursework. The dissertation presents findings that museum-school partnerships can use in order to develop...

  12. Brain PET scan

    Science.gov (United States)

    ... results on a PET scan. Blood sugar or insulin levels may affect the test results in people with diabetes . PET scans may be done along with a CT scan. This combination scan is called a PET/CT. Alternative Names Brain positron emission tomography; PET scan - brain References Chernecky ...

  13. EPR dosimetry of radiotherapy photon beams in inhomogeneous media using alanine films

    Energy Technology Data Exchange (ETDEWEB)

    Oesteraas, Bjoern Helge [Department of Radiation Biology, Institute for Cancer Research, Norwegian Radium Hospital, Montebello, N-0310 Oslo (Norway); Hole, Eli Olaug [Department of Physics, University of Oslo, PO Box 1048 Blindern, N-0316 Oslo (Norway); Olsen, Dag Rune [Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, N-0310 Oslo (Norway); Malinen, Eirik [Department of Radiation Biology, Institute for Cancer Research, The Norwegian Radium Hospital, Montebello, N-0310 Oslo (Norway)

    2006-12-21

    In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 {mu}m thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity. The phantoms were irradiated to a maximum dose of about 30 Gy with 6 or 15 MV photons. The performance of the alanine film dosimeters was investigated and compared to results from ion chamber dosimetry, Monte Carlo simulations and radiotherapy treatment planning calculations. It was found that the alanine film dosimeters had a linear dose response above approximately 5 Gy, while a background signal obscured the response at lower dose levels. For doses between 5 and 60 Gy, the standard deviation of single alanine film dose estimates was about 2%. The alanine film dose estimates yielded results comparable to those from the Monte Carlo simulations and the ion chamber measurements, with absolute differences between estimates in the order of 1-15%. The treatment planning calculations exhibited limited applicability. The current work shows that alanine film dosimetry is a method suitable for estimating radiotherapeutical doses and for dose measurements in inhomogeneous media.

  14. EPR dosimetry of radiotherapy photon beams in inhomogeneous media using alanine films

    International Nuclear Information System (INIS)

    Oesteraas, Bjoern Helge; Hole, Eli Olaug; Olsen, Dag Rune; Malinen, Eirik

    2006-01-01

    In the current work, EPR (electron paramagnetic resonance) dosimetry using alanine films (134 μm thick) was utilized for dose measurements in inhomogeneous phantoms irradiated with radiotherapy photon beams. The main phantom material was PMMA, while either Styrofoam or aluminium was introduced as an inhomogeneity. The phantoms were irradiated to a maximum dose of about 30 Gy with 6 or 15 MV photons. The performance of the alanine film dosimeters was investigated and compared to results from ion chamber dosimetry, Monte Carlo simulations and radiotherapy treatment planning calculations. It was found that the alanine film dosimeters had a linear dose response above approximately 5 Gy, while a background signal obscured the response at lower dose levels. For doses between 5 and 60 Gy, the standard deviation of single alanine film dose estimates was about 2%. The alanine film dose estimates yielded results comparable to those from the Monte Carlo simulations and the ion chamber measurements, with absolute differences between estimates in the order of 1-15%. The treatment planning calculations exhibited limited applicability. The current work shows that alanine film dosimetry is a method suitable for estimating radiotherapeutical doses and for dose measurements in inhomogeneous media

  15. Accurate measurement of the optical activity of alanine crystals and the determination of their absolute chirality

    Science.gov (United States)

    Ishikawa, Kazuhiko; Terasawa, Yukana; Tanaka, Masahito; Asahi, Toru

    2017-05-01

    Wavelength dependence measurements of the chiroptical properties in alanine crystals have so far been unsuccessful using conventional spectroscopic techniques. We describe our attempts to measure the wavelength dependence of the optical activity in L- and D-alanine crystals along each crystallographic axis, and to determine the absolute chirality of alanine crystals by correlating the absolute structure to the optical activity using an x-ray diffractometer and a generalized high accuracy universal polarimeter. We have succeeded in accurately measuring the optical rotatory dispersion in the direction, which shows that the optical rotation of the D-alanine crystal is dextrorotatory and that of the L-alanine crystal is laevorotatory, thereby determining the absolute chirality. Furthermore, comparison with the optical activity in solution shows that the optical activity in alanine crystals is different not only in value, but also in the sign. These results have led us to conclude that the optical rotatory power in the crystalline state should not be simply the summation of molecular optical rotatory power values. We propose the necessity of a theory, which contains the contribution of molecular interactions within the crystal, in order to calculate the optical rotatory power of the crystalline state.

  16. [Alanine solution as enzyme reaction buffer used in A to O blood group conversion].

    Science.gov (United States)

    Li, Su-Bo; Zhang, Xue; Zhang, Yin-Ze; Tan, Ying-Xia; Bao, Guo-Qiang; Wang, Ying-Li; Ji, Shou-Ping; Gong, Feng; Gao, Hong-Wei

    2014-06-01

    The aim of this study was to investigate the effect of alanine solution as α-N-acetylgalactosaminidase enzyme reaction buffer on the enzymatic activity of A antigen. The binding ability of α-N-acetylgalactosaminidase with RBC in different reaction buffer such as alanine solution, glycine solution, normal saline (0.9% NaCl), PBS, PCS was detected by Western blot. The results showed that the efficiency of A to O conversion in alanine solution was similar to that in glycine solution, and Western blot confirmed that most of enzymes blinded with RBC in glycine or alanine solution, but few enzymes blinded with RBC in PBS, PCS or normal saline. The evidences indicated that binding of enzyme with RBC was a key element for A to O blood group conversion, while the binding ability of α-N-acetylgalactosaminidase with RBC in alanine or glycine solution was similar. It is concluded that alanine solution can be used as enzyme reaction buffer in A to O blood group conversion. In this buffer, the α-N-acetylgalactosaminidase is closely blinded with RBC and α-N-acetylgalactosaminidase plays efficient enzymatic activity of A antigen.

  17. Dynamics of solid alanine by means of nuclear magnetic resonance relaxometry

    Science.gov (United States)

    Kubica-Misztal, A.; Rochowski, P.; Florek-Wojciechowska, M.; Kruk, D.

    2017-04-01

    1H nuclear magnetic resonance relaxometry was applied to investigate the dynamics of l-alanine in the solid phase (powder). The experimental studies were carried out in a very broad frequency range, covering four orders of magnitude—from 4 kHz to 40 MHz (referring to the 1H resonance frequency) in order to probe motional processes of much different time scales by a single experiment. To get access to the dynamics of different proton groups of alanine, the 1H spin-lattice relaxation measurements were performed for non-deuterated and partially deuterated alanine. The experiments were carried out in the temperature range of 293 K-370 K (non-deuterated alanine) and 318 K-370 K (partially deuterated alanine). As a result of a thorough theoretical analysis of the extensive set of experimental results, three motional processes occurring on different time scales are identified and quantitatively described. The slowest process occurs on a time scale of μs and it is attributed to the collective dynamics of a 3D hydrogen bond network of alanine, while the intermediate, attributed to the dynamics of the NH3 group, corresponds to the range of tenths of ns. The fast process describes the rotation of the CH3 group.

  18. An efficient protocol for the complete incorporation of methyl-protonated alanine in perdeuterated protein

    International Nuclear Information System (INIS)

    Ayala, Isabel; Sounier, Remy; Use, Nathalie; Gans, Pierre; Boisbouvier, Jerome

    2009-01-01

    A strategy for the introduction of ( 1 H, 13 C-methyl)-alanine into perdeuterated proteins is described. Specific protonation of alanine methyl groups to a level of 95% can be achieved by overexpressing proteins in M9/D 2 O based bacterial growth medium supplemented with 800 mg/l of 2-[ 2 H], 3-[ 13 C] l-alanine. However, though simple, this approach results in undesired, non-specific background labeling due to isotope scrambling via different amino acid metabolic pathways. Following a careful analysis of known metabolic pathways we found that co-addition of perdeuterated forms of α-ketoisovalerate-d 7 , succinate-d 4 and l-isoleucine-d 10 with labeled l-alanine, reduces undesired background labeling to <1%. When combined with recently developed methyl TROSY experiments, this methyl-specific labeling protocol permits the acquisition of excellent quality correlation spectra of alanine methyl groups in high molecular weight proteins. Our cost effective strategy offers a significant enhancement in the level of incorporation of methyl-labeled alanine in overexpressed proteins over previously reported methods

  19. Dose intercomparison study involving Fricke, ethanol chlorobenzene, PMMA and alanine dosimeters

    International Nuclear Information System (INIS)

    Lanuza, L.G.; Cabalfin, E.G.; Kojima, T.; Tachibana, H.

    1999-01-01

    A dose intercomparison study was carried out between the Philippine Nuclear Research Institute (PNRI) and Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute (JAERI) to determine reliability of the dosimetry systems being used by PNRI employing ethanol chlorobenzene (ECB), Fricke and alanine dosimeters. The Fricke and ECB dosimeters were prepared at PNRI while the alanine-polystyrene dosimeter was provided by JAERI. Fricke or ECB dosimeters were irradiated together with alanine at PNRI gamma irradiation facilities. Analyses of the Fricke and ECB dosimeters were performed at PNRI while alanine dosimeters were analyzed at JAERI. A comparison study between alanine and polymethylmethacrylate (PMMA, Radix RN15) dosimeters was also undertaken at JAERI. The dosimeters were irradiated together under different irradiation conditions using the gamma irradiation facilities of JAERI and Radia Industry Co. Ltd. (Japan). Evaluations of PMMA and alanine dosimeters were both performed at JAERI. Result of the dose intercomparison of PNRI with the International Atomic Energy Agency through the International Dose Assurance Service (IDAS) is also presented. (author)

  20. Dose intercomparison study involving Fricke, ethanol chlorobenzene, PMMA and alanine dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Lanuza, L G; Cabalfin, E G [Philippine Nuclear Research Institute, Quezon City (Philippines); Kojima, T; Tachibana, H [Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research institute, Takasaki (Japan)

    1999-03-01

    A dose intercomparison study was carried out between the Philippine Nuclear Research Institute (PNRI) and Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute (JAERI) to determine reliability of the dosimetry systems being used by PNRI employing ethanol chlorobenzene (ECB), Fricke and alanine dosimeters. The Fricke and ECB dosimeters were prepared at PNRI while the alanine-polystyrene dosimeter was provided by JAERI. Fricke or ECB dosimeters were irradiated together with alanine at PNRI gamma irradiation facilities. Analyses of the Fricke and ECB dosimeters were performed at PNRI while alanine dosimeters were analyzed at JAERI. A comparison study between alanine and polymethylmethacrylate (PMMA, Radix RN15) dosimeters was also undertaken at JAERI. The dosimeters were irradiated together under different irradiation conditions using the gamma irradiation facilities of JAERI and Radia Industry Co. Ltd. (Japan). Evaluations of PMMA and alanine dosimeters were both performed at JAERI. Result of the dose intercomparison of PNRI with the International Atomic Energy Agency through the International Dose Assurance Service (IDAS) is also presented. (author) 8 refs, 3 figs, 4 tabs

  1. Synthesis of silver nanoparticles using DL-alanine for ESR dosimetry applications

    International Nuclear Information System (INIS)

    Guidelli, Eder José; Ramos, Ana Paula; Zaniquelli, Maria Elisabete D.; Nicolucci, Patricia; Baffa, Oswaldo

    2012-01-01

    The potential use of alanine for the production of nanoparticles is presented here for the first time. Silver nanoparticles were synthesized using a simple green method, namely the thermal treatment of silver nitrate aqueous solutions with DL-alanine. The latter compound was employed both as a reducing and a capping agent. Particles with average size equal to 7.5 nm, face-centered cubic crystalline structure, narrow size distribution, and spherical shape were obtained. Interaction between the silver ions present on the surface of the nanoparticles and the amine group of the DL-alanine molecule seems to be responsible for reduction of the silver ions and for the stability of the colloid. The bio-hybrid nano-composite was used as an ESR dosimeter. The amount of silver nanoparticles in the nanocomposite was not sufficient to cause considerable loss of tissue equivalency. Moreover, the samples containing nanoparticles presented increased sensitivity and reduced energetic dependence as compared with pure DL-alanine, contributing to the construction of small-sized dosimeters. - Highlights: ► The synthesis is environmentally benign, easy to perform, and of low-cost. ► DL-Alanine was employed both as reducing and capping agent. ► Mean size of 7.5 nm, narrow size distribution, and spherical shape of particles. ► Increased sensitivity and reduced energetic dependence compared with pure alanine. ► The nanocomposite has potential application for ESR dosimetry.

  2. Heart PET scan

    Science.gov (United States)

    ... nuclear medicine scan; Heart positron emission tomography; Myocardial PET scan ... A PET scan requires a small amount of radioactive material (tracer). This tracer is given through a vein (IV), ...

  3. Interface Screenings

    DEFF Research Database (Denmark)

    Thomsen, Bodil Marie Stavning

    2015-01-01

    In Wim Wenders' film Until the End of the World (1991), three different diagrams for the visual integration of bodies are presented: 1) GPS tracking and mapping in a landscape, 2) video recordings layered with the memory perception of these recordings, and 3) data-created images from dreams...... and memories. From a transvisual perspective, the question is whether or not these (by now realized) diagrammatic modes involving the body in ubiquitous global media can be analysed in terms of the affects and events created in concrete interfaces. The examples used are filmic as felt sensations...

  4. Electron Paramagnetic Resonance signal ratio of Alanine Pellets In Nuclear Power Plants

    International Nuclear Information System (INIS)

    Choi, Hoon; Sung, In Bok; Lee, Byung Il; Lim, Young Ki

    2011-01-01

    As a dosimeter for ESR dosimetry, alanine has many useful features including relatively long endurance time of radicals and almost no difference with the radiation dose rate and radiation quality. Alanine dosimeters have been accepted as transfer dosimeters for their good precision at high radiation range. For alanine/ESR spectra, it was reported that the peaks of the spectra are due to the three kinds of radicals induced by radiation. The ratio of the weak 'satellite line' and the central peak of the three man in alanine specta(in this study x /y ratio ) are changed on the LET value of radiation. In case of lithium formate monohydrate was recently identified as a promising dosimetric material. in addition, it was reported the the peak height in the signal spectra is not easily saturated when power is irradiated with relatively high LET radiation such as neutron rays. The difference in the peak height ratio was reported to be caused by increased local radical density following the radiation of high LET. The spectrum shape of some alanine dosimeter installed in the containment buildings of NPPs showed differences in comparison with dosimeters exposed only to gamma rays. There was apparent change of spectra, expressed as the 'x/y ratio'. As noted in other papers, high LET radiation such as neutron rays causes shape changes of the spectrum of alanine dosimeters. Thus, the unanticipated high dose level and low 'x/y ratio' of some alanine dosimeters from the containment building could be explained b exposure to mixed radiation with high LET. Generally, the locations evaluated in this study are regarded as being exposed only to gamma rays, because the positions are blocked from direct neutron rays, because the positions are blocked from direct neutron rays from reactor by thick cement barriers and heavy instruments.

  5. Relationship between turnover rate and oxidation rate of alanine in the post-absorptive state and during parenteral nutrition before and after surgery

    NARCIS (Netherlands)

    Sauerwein, H. P.; Michels, R. P.; Cejka, V.

    1985-01-01

    The influence of total parenteral nutrition and stomach resection on alanine turnover rate and alanine oxidation rate was measured in ten patients after single injection of U-14 C-alanine. Sequential studies were done in three patients. During parenteral nutrition alanine turnover was significantly

  6. Enzymatic biosensor based on entrapment of d-amino acid oxidase on gold nanofilm/MWCNTs nanocomposite modified glassy carbon electrode by sol-gel network: Analytical applications for d-alanine in human serum.

    Science.gov (United States)

    Shoja, Yalda; Rafati, Amir Abbas; Ghodsi, Javad

    2017-05-01

    Sensing and determination of d-alanine is studied by using an enzymatic biosensor which was constructed on the basis of d-amino acid oxidase (DAAO) immobilization by sol-gel film onto glassy carbon electrode surface modified with nanocomposite of gold nanofilm (Au-NF) and multiwalled carbon nanotubes (MWCNTs). The Au-NF/MWCNT nanocomposite was prepared by applying the potentiostatic technique for electrodeposition of Au-NF on the MWCNT immobilized on glassy carbon electrode surface. The modified electrode is investigated by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), linear sweep voltammetry (LSV) and cyclic voltammetry(CV) techniques. The linear sweep voltammetry was used for determination of d-alanine and the results showed an excellent linear relationship between biosensor response and d-alanine concentration ranging from 0.25μM to 4.5μM with correction coefficient of 0.999 (n=20). Detection limit for the fabricated sensor was calculated about 20nM (for S/N=3) and sensitivity was about 56.1μAμM -1 cm -2 . The developed biosensor exhibited rapid and accurate response to d-alanine, a good stability (4 weeks) and an average recovery of 98.9% in human serum samples. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. L-alanine-induced germination in Bacillus licheniformis -the impact of native gerA sequences.

    Science.gov (United States)

    Madslien, Elisabeth H; Granum, Per Einar; Blatny, Janet M; Lindbäck, Toril

    2014-04-22

    L-alanine, acting through the GerA receptor, was recently found to be an efficient germinant in Bacillus licheniformis ATCC14580/DSM13. In this study, we show that several of 46 examined B. licheniformis strains germinate remarkably slower than the type strain when exposed to L-alanine. These strains are not necessarily closely related, as determined by MLST (multi-locus sequence typing). Three of the slow-germinating strains were further examined in order to see whether nucleotide substitutions in the gerA sequences were responsible for the slow L-alanine germination. This was performed by complementing the transformable type strain derivate MW3ΔgerAA with gerA variants from the three slow-germinating strains; NVH1032, NVH1112 and NVH800. A wide selection of B. licheniformis strains was evaluated for L-alanine-induced germination efficiency. Our results show that gerA substitutions could only partially explain why spores of some B. licheniformis strains responded slower than others in the presence of L-alanine.

  8. Isotope effect of optical activity measurements on L-α-alanine

    International Nuclear Information System (INIS)

    Darge, W.; Laczko, I.; Thiemann, W.

    1976-01-01

    If an optically active organic substance is labelled in the chirality center with another isotopic species (such as 15 N for 14 N) a pronounced variation of rotatory power is predicted. It was tried to varify this idea experimentally on L-α-alanine and found an isotope effect in ORD (optical rotatory dispersion). The magnitude of the rotation is mainly dependent on the pH of the solvent. The ratio of the optical activity alanine- 14 N/alanine- 15 N is about 1.02. It can be seen that the ratios of the molecular rotations are consistently lower than the corresponding ratios of the specific rotations. This is of course due to the fact that the molecular mass 15 M is larger than 14 M. This means tthat the mass difference is already taken into account so that the ratio of the molecular rotations could be defined as the ''net'' isotope effect in the ORDs of 15 N-substitued alanine. From the fact the ORD is different for the isotope-substitued alanine, one can reasonably assume that the absorption coefficient is also different. This leads to speculations about certain problems in the chemical evolution of the biosphere, such as the origin of optical activity. (T.G.)

  9. Alanine and TLD coupled detectors for fast neutron dose measurements in neutron capture therapy (NCT)

    Energy Technology Data Exchange (ETDEWEB)

    Cecilia, A.; Baccaro, S.; Cemmi, A. [ENEA-FIS-ION, Casaccia RC, Via Anguillarese 301, 00060 Santa Maria di Galeria, Rome (Italy); Colli, V.; Gambarini, G. [Dept. of Physics of the Univ., INFN, Via Celoria 16, 20133 Milan (Italy); Rosi, G. [ENEA-FIS-ION, Casaccia RC, Via Anguillarese 301, 00060 Santa Maria di Galeria, Rome (Italy); Scolari, L. [Dept. of Physics of the Univ., INFN, Via Celoria 16, 20133 Milan (Italy)

    2004-07-01

    A method was investigated to measure gamma and fast neutron doses in phantoms exposed to an epithermal neutron beam designed for neutron capture therapy (NCT). The gamma dose component was measured by TLD-300 [CaF{sub 2}:Tm] and the fast neutron dose, mainly due to elastic scattering with hydrogen nuclei, was measured by alanine dosemeters [CH{sub 3}CH(NH{sub 2})COOH]. The gamma and fast neutron doses deposited in alanine dosemeters are very near to those released in tissue, because of the alanine tissue equivalence. Couples of TLD-300 and alanine dosemeters were irradiated in phantoms positioned in the epithermal column of the Tapiro reactor (ENEA-Casaccia RC). The dosemeter response depends on the linear energy transfer (LET) of radiation, hence the precision and reliability of the fast neutron dose values obtained with the proposed method have been investigated. Results showed that the combination of alanine and TLD detectors is a promising method to separate gamma dose and fast neutron dose in NCT. (authors)

  10. Effect of β-alanine supplementation on 20 km cycling time trial performance

    Directory of Open Access Journals (Sweden)

    Ruth Margaret JAMES

    2014-09-01

    Full Text Available The effects of β-alanine supplementation on high-intensity cycling performance and capacity have been evaluated, although the effects on longer duration cycling performance are unclear. Nineteen UK category 1 male cyclists completed four 20 km cycling time trials, two before and two after supplementation with either 6.4 g•d-1 β-alanine (n = 10; BA or a matched placebo (n = 9; P. Performance time for the 20 km time trial and 1 km split times were recorded. There was no significant effect of β-alanine supplementation on 20 km time trial performance (BA-pre 1943 ± 129 s; BA-post 1950 ± 147 s; P-pre 1989 ± 106 s; P-post 1986 ± 115 s or on the performance of each 1 km split. The effect of β-alanine on 20 km time trial performance was deemed unclear as determined by magnitude based inferences. Supplementation with 6.4 g•d-1 of β-alanine for 4 weeks did not affect 20 km cycling time trial performance in well trained male cyclists.

  11. Optical signal response pf the alanine gel solution for photons and electrons clinical beams

    International Nuclear Information System (INIS)

    Silva, Cleber Feijo; Campos, Leticia Lucente

    2009-01-01

    Alanine gel dosimeter is a new gel material developed at IPEN that presents significant improvement on previous alanine systems developed by Costa (1994). The measure technique is based on the transformation of ferrous ions (Fe 2+ ) in ferric ions (Fe 3+ ) after irradiation. The DL-Alanine (C 3 H 7 NO 2 ) is an aminoacid tissue equivalent that improves the production of ferric ions in the solution. This work aims to study the comparison of optical signal response of the alanine gel solution for photons and electrons clinical beams. It was observed that the calibration factor can be considered independent of quality of the radiation for photons and electrons clinical beams. Therefore, it can be used the same calibration factor for evaluating the absorbed dose in photons and electrons fields in the energy of 6 MeV. Alanine Gel Dosimeter presents good performance and can be useful as alternative dosimeter in the radiotherapy area using MRI technique for 3D dose distribution evaluation. (author)

  12. ald of Mycobacterium tuberculosis Encodes both the Alanine Dehydrogenase and the Putative Glycine Dehydrogenase

    Science.gov (United States)

    Giffin, Michelle M.; Modesti, Lucia; Raab, Ronald W.; Wayne, Lawrence G.

    2012-01-01

    The putative glycine dehydrogenase of Mycobacterium tuberculosis catalyzes the reductive amination of glyoxylate to glycine but not the reverse reaction. The enzyme was purified and identified as the previously characterized alanine dehydrogenase. The Ald enzyme was expressed in Escherichia coli and had both pyruvate and glyoxylate aminating activities. The gene, ald, was inactivated in M. tuberculosis, which resulted in the loss of all activities. Both enzyme activities were found associated with the cell and were not detected in the extracellular filtrate. By using an anti-Ald antibody, the protein was localized to the cell membrane, with a smaller fraction in the cytosol. None was detected in the extracellular medium. The ald knockout strain grew without alanine or glycine and was able to utilize glycine but not alanine as a nitrogen source. Transcription of ald was induced when alanine was the sole nitrogen source, and higher levels of Ald enzyme were measured. Ald is proposed to have several functions, including ammonium incorporation and alanine breakdown. PMID:22210765

  13. Alanine Counteracts the Destabilizing Effect that Urea has on RNase-A.

    Science.gov (United States)

    Chowhan, Rimpy K; Ali, Fasil; Bhat, Mohd Y; Rahman, Safikur; Singh, Laishram R; Ahmad, Faizan; Dar, Tanveer A

    2016-01-01

    It is generally believed that organisms use and accumulate methylamine osmolytes to prevent urea's damaging effect on protein stability and activity. However, urea-rich cells not only accumulate methylamines but also many other methylated and non-methylated compounds as well. But, so far it is not known whether osmolytes that are not accumulated in urea-rich cells could also confer urea-counteracting properties. We investigated the behavior of a non-methylamine osmolyte, alanine for its counteracting effect against urea denaturation of a model protein, ribonuclease A (RNase-A). We have measured structure and thermodynamic parameters (Tm, ΔHm, and ΔGD°) of RNase-A in the presence of alanine, urea and their combination. The results were also compared with the ability of glycine (osmolyte lacking one methyl group when compared with alanine) to counter urea's effect on protein stability. We observed that alanine but not glycine counteracts urea's harmful effect on RNase-A stability. The results indicated that alanine (in addition to methylamine osmolytes) may serve as an alternate urea-counteractant. Since glycine fails to protect RNase-A from urea's destabilizing effect, it seems that methylation to glycine might have some evolutionary significance to protect proteins against harmful effects of urea.

  14. Perturbation correction for alanine dosimeters in different phantom materials in high-energy photon beams.

    Science.gov (United States)

    von Voigts-Rhetz, P; Anton, M; Vorwerk, H; Zink, K

    2016-02-07

    In modern radiotherapy the verification of complex treatments plans is often performed in inhomogeneous or even anthropomorphic phantoms. For dose verification small detectors are necessary and therefore alanine detectors are most suitable. Though the response of alanine for a wide range of clinical photon energies in water is well know, the knowledge about the influence of the surrounding phantom material on the response of alanine is sparse. Therefore we investigated the influence of twenty different surrounding/phantom materials for alanine dosimeters in clinical photon fields via Monte Carlo simulations. The relative electron density of the used materials was in the range [Formula: see text] up to 1.69, covering almost all materials appearing in inhomogeneous or anthropomorphic phantoms used in radiotherapy. The investigations were performed for three different clinical photon spectra ranging from 6 to 25 MV-X and Co-60 and as a result a perturbation correction [Formula: see text] depending on the environmental material was established. The Monte Carlo simulation show, that there is only a small dependence of [Formula: see text] on the phantom material and the photon energy, which is below  ±0.6%. The results confirm the good suitability of alanine detectors for in-vivo dosimetry.

  15. ESR investigation of L-α-alanine and sucrose radicals produced by heavy-ion irradiation

    International Nuclear Information System (INIS)

    Nakagawa, K.; Sato, Y.

    2005-01-01

    We investigated sucrose and L-α-alanine radicals produced by heavy (particle) ion irradiation with various LETs (linear energy transfer). The impact of the heavy ions on the samples produced stable free radicals, which were analyzed by ESR (electron spin resonance). Identical spectra were measured after one year. The obtained spectral patterns were the same as those for helium (He), carbon (C), and neon (Ne) ions irradiation. The absorbed dose dependences for the irradiated sucrose and alanine samples were examined. The ESR response has a linear relation with the absorbed dose. The ESR response at 60 Gy was slightly lower than a linear line for sucrose; however, the response showed good linearity for the alanine. In addition, the total spin concentration obtained by heavy-ion irradiation correlated logarithmically with the LET. Qualitative ESR analyse showed that the production of sucrose and alanine radicals depended on both different particle irradiation and the LET under the same dose. Thus, the present ESR results imply that sucrose together with L-α-alanine can be used to monitor LET as well as the number of ionizing particle for the production of stable free radicals. (author)

  16. Development of portable ESR spectrometer as a reader for alanine dosimeters

    International Nuclear Information System (INIS)

    Kojima, T.; Haruyama, Y.; Tachibana, H.; Tanaka, R.; Okamoto, J.

    1993-01-01

    A prototype portable electron spin resonance (ESR) spectrometer was designed and tested, and its feasibility as a reader of alanine dosimeters was studied from the two standpoints of reproducibility of readings and sensitivity sufficient for dosimetry in the absorbed dose range 1-100 kGy. It has two main components: a permanent magnet and resonator; and a unit box with a microwave and auto-frequency control (AFC) circuit, a sweep controller of magnetic field, display, etc. In the present preliminary study, reproducibility values are measured with the same ESR parameters and alanine-polystyrene (alanine-PS) dosimeter at a dose of 1 kGy: repeatedly measuring without removing dosimeter from the cavity; individual measurement with removing and inserting again into the cavity with readjustment of ESR parameters. Alanine/ESR dosimetry using this spectrometer has a measurable dose range from 1 to 100 kGy with relatively high precision within ± 3% (1σ) as a preliminary result. The portable ESR spectrometer may also be modified as an automatic, more precise, dedicated alanine dosimeter reader. (author)

  17. Museets interface

    DEFF Research Database (Denmark)

    Pold, Søren

    2007-01-01

    Søren Pold gør sig overvejelser med udgangspunkt i museumsprojekterne Kongedragter.dk og Stigombord.dk. Han argumenterer for, at udviklingen af internettets interfaces skaber nye måder at se, forstå og interagere med kulturen på. Brugerne får nye medievaner og perceptionsmønstre, der må medtænkes i...... tilrettelæggelsen af den fremtidige formidling. Samtidig får museets genstande en ny status som flygtige ikoner i det digitale rum, og alt i alt inviterer det til, at museerne kan forholde sig mere åbent og eksperimenterende til egen praksis og rolle som kulturinstitution....

  18. The Uncertainty estimation of Alanine/ESR dosimetry

    International Nuclear Information System (INIS)

    Kim, Bo Rum; An, Jin Hee; Choi, Hoon; Kim, Young Ki

    2008-01-01

    Machinery, tools and cable etc are in the nuclear power plant which environment is very severe. By measuring actual dose, it needs for extending life expectancy of the machinery and tools and the cable. Therefore, we estimated on dose (gamma ray) of Wolsong nuclear power division 1 by dose estimation technology for three years. The dose estimation technology was secured by ESR(Electron Spin Resonance) dose estimation using regression analysis. We estimate uncertainty for secure a reliability of results. The uncertainty estimation will be able to judge the reliability of measurement results. The estimation of uncertainty referred the international unified guide in order; GUM(Guide to the Expression of Uncertainty in Measurement). It was published by International Standardization for Organization (ISO) in 1993. In this study the uncertainty of e-scan and EMX those are ESR equipment were evaluated and compared. Base on these results, it will improve the reliability of measurement

  19. Characterization of the l-alanine exporter AlaE of Escherichia coli and its potential role in protecting cells from a toxic-level accumulation of l-alanine and its derivatives

    OpenAIRE

    Kim, Seryoung; Ihara, Kohei; Katsube, Satoshi; Hori, Hatsuhiro; Ando, Tasuke; Isogai, Emiko; Yoneyama, Hiroshi

    2015-01-01

    We previously reported that the alaE gene of Escherichia coli encodes the l-alanine exporter AlaE. The objective of this study was to elucidate the mechanism of the AlaE exporter. The minimum inhibitory concentration of l-alanine and l-alanyl-l-alanine in alaE-deficient l-alanine-nonmetabolizing cells MLA301ΔalaE was 4- and >4000-fold lower, respectively, than in the alaE-positive parent cells MLA301, suggesting that AlaE functions as an efflux pump to avoid a toxic-level accumulation of intr...

  20. Substrate specificity of the aspartate:alanine antiporter (AspT) of Tetragenococcus halophilus in reconstituted liposomes.

    Science.gov (United States)

    Sasahara, Ayako; Nanatani, Kei; Enomoto, Masaru; Kuwahara, Shigefumi; Abe, Keietsu

    2011-08-19

    The aspartate:alanine antiporter (AspT) of the lactic acid bacterium Tetragenococcus halophilus is a member of the aspartate:alanine exchanger (AAEx) transporter family. T. halophilus AspT catalyzes the electrogenic exchange of L-aspartate(1-) with L-alanine(0). Although physiological functions of AspT were well studied, L-aspartate(1-):L-alanine(0) antiport mechanisms are still unsolved. Here we report that the binding sites of L-aspartate and L-alanine are independently present in AspT by means of the kinetic studies. We purified His(6)-tagged T. halophilus AspT and characterized its kinetic properties when reconstituted in liposomes (K(m) = 0.35 ± 0.03 mm for L-aspartate, K(m) = 0.098 ± 0 mm for D-aspartate, K(m) = 26 ± 2 mm for L-alanine, K(m) = 3.3 ± 0.2 mm for D-alanine). Competitive inhibition by various amino acids of L-aspartate or L-alanine in self-exchange reactions revealed that L-cysteine selectively inhibited L-aspartate self-exchange but only weakly inhibited L-alanine self-exchange. Additionally, L-serine selectively inhibited L-alanine self-exchange but barely inhibited L-aspartate self-exchange. The aspartate analogs L-cysteine sulfinic acid, L-cysteic acid, and D-cysteic acid competitively and strongly inhibited L-aspartate self-exchange compared with L-alanine self-exchange. Taken together, these kinetic data suggest that the putative binding sites of L-aspartate and L-alanine are independently located in the substrate translocation pathway of AspT.

  1. Lack of Effect of Sodium Benzoate at Reported Clinical Therapeutic Concentration on d-Alanine Metabolism in Dogs.

    Science.gov (United States)

    Popiolek, Michael; Tierney, Brendan; Steyn, Stefanus J; DeVivo, Michael

    2018-06-19

    Cognitive decline and psychosis have been hypothesized to be mediated by N-methyl-d-aspartate receptor (NMDAR) hypofunction. Consistent with this hypothesis, chronic treatment with d-alanine, a coagonist at the glycine site of the NMDAR, leads to an improvement of positive and cognitive symptoms in schizophrenic patients. d-alanine is oxidized by d-amino acid oxidase (DAAO); thus, an inhibitor of DAAO would be expected to enhance d-alanine levels and likewise lead to desirable clinical outcomes. Sodium benzoate, on the basis of d-amino acid inhibition, was observed to display beneficial clinical effects in schizophrenic and Alzheimer's patients. However, in the clinical pilot studies using sodium benzoate, d-amino acids were not quantified to verify that sodium benzoate's efficacy was mediated through DAAO inhibition. In this study, d-alanine content was monitored in cerebral spinal fluid (CSF) of dogs treated with daily injections of d-alanine (30 mg/kg) alone and in combination with sodium benzoate (30 mg/kg) for seven consecutive days. We reasoned that the cerebral spinal fluid d-alanine quantity is reflective of the brain d-alanine levels and it would increase as a consequence of DAAO inhibition with sodium benzoate. We found that d-alanine treatment lead to maximal concentration of 7.51 μM CSF d-alanine level; however, coadministration of sodium benzoate and d-alanine did not change CSF d-alanine level beyond that of d-alanine treatment alone. As a consequence, we conclude that clinical efficacy associated with chronic administration of sodium benzoate in schizophrenic and Alzheimer's patients is likely not mediated through inhibition of DAAO.

  2. Mechanism of mercurial inhibition of sodium-coupled alanine uptake in liver plasma membrane vesicles from Raja erinacea

    International Nuclear Information System (INIS)

    Sellinger, M.; Ballatori, N.; Boyer, J.L.

    1991-01-01

    In mammalian hepatocytes the L-alanine carrier contains a sulfhydryl group that is essential for its activity and is inhibited by mercurials. In hepatocytes of the evolutionarily primitive little skate (Raja erinacea), HgCl2 inhibits Na(+)-dependent alanine uptake and Na+/K(+)-ATPase and increase K+ permeability. To distinguish between direct effects of HgCl2 on the Na(+)-alanine cotransporter and indirect effects on membrane permeability, [3H]alanine transport was studied in plasma membrane vesicles. [3H]Alanine uptake was stimulated by an out-to-in Na+ but not K+ gradient and was saturable confirming the presence of Na(+)-alanine cotransport in liver plasma membranes from this species. Preincubation of the vesicles with HgCl2 for 5 min reduced initial rates of Na(+)-dependent but not Na(+)-independent alanine uptake in a dose-dependent manner (10-200 microM). In the presence of equal concentrations of NaCl or KCl inside and outside of the vesicles, 75 microM HgCl2 directly inhibited sodium-dependent alanine-[3H]alanine exchange, demonstrating that HgCl2 directly affected the alanine cotransporter. Inhibition of Na(+)-dependent alanine uptake by 30 microM HgCl2 was reversed by dithiothreitol (1 mM). HgCl2 (10-30 microM) also increased initial rates of 22Na uptake (at 5 sec), whereas 22Na uptake rates were decreased at HgCl2 concentrations greater than 50 microM. Higher concentrations of HgCl2 (100-200 microM) produced nonspecific effects on vesicle integrity. These studies indicate that HgCl2 inhibits Na(+)-dependent alanine uptake in skate hepatocytes by three different concentration-dependent mechanisms: direct interaction with the transporters, dissipation of the driving force (Na+ gradient), and loss of membrane integrity

  3. Comparison of the UDP-N-Acetylmuramate:l-Alanine Ligase Enzymes from Mycobacterium tuberculosis and Mycobacterium leprae

    Science.gov (United States)

    Mahapatra, Sebabrata; Crick, Dean C.; Brennan, Patrick J.

    2000-01-01

    In the peptidoglycan of Mycobacterium leprae, l-alanine of the side chain is replaced by glycine. When expressed in Escherichia coli, MurC (UDP-N-acetyl-muramate:l-alanine ligase) of M. leprae showed Km and Vmax for l-alanine and glycine similar to those of Mycobacterium tuberculosis MurC, suggesting that another explanation should be sought for the presence of glycine. PMID:11073931

  4. Comparison of the UDP-N-Acetylmuramate:l-Alanine Ligase Enzymes from Mycobacterium tuberculosis and Mycobacterium leprae

    OpenAIRE

    Mahapatra, Sebabrata; Crick, Dean C.; Brennan, Patrick J.

    2000-01-01

    In the peptidoglycan of Mycobacterium leprae, l-alanine of the side chain is replaced by glycine. When expressed in Escherichia coli, MurC (UDP-N-acetyl-muramate:l-alanine ligase) of M. leprae showed Km and Vmax for l-alanine and glycine similar to those of Mycobacterium tuberculosis MurC, suggesting that another explanation should be sought for the presence of glycine.

  5. Substrate Specificity of the Aspartate:Alanine Antiporter (AspT) of Tetragenococcus halophilus in Reconstituted Liposomes*

    Science.gov (United States)

    Sasahara, Ayako; Nanatani, Kei; Enomoto, Masaru; Kuwahara, Shigefumi; Abe, Keietsu

    2011-01-01

    The aspartate:alanine antiporter (AspT) of the lactic acid bacterium Tetragenococcus halophilus is a member of the aspartate:alanine exchanger (AAEx) transporter family. T. halophilus AspT catalyzes the electrogenic exchange of l-aspartate1− with l-alanine0. Although physiological functions of AspT were well studied, l-aspartate1−:l-alanine0 antiport mechanisms are still unsolved. Here we report that the binding sites of l-aspartate and l-alanine are independently present in AspT by means of the kinetic studies. We purified His6-tagged T. halophilus AspT and characterized its kinetic properties when reconstituted in liposomes (Km = 0.35 ± 0.03 mm for l-aspartate, Km = 0.098 ± 0 mm for d-aspartate, Km = 26 ± 2 mm for l-alanine, Km = 3.3 ± 0.2 mm for d-alanine). Competitive inhibition by various amino acids of l-aspartate or l-alanine in self-exchange reactions revealed that l-cysteine selectively inhibited l-aspartate self-exchange but only weakly inhibited l-alanine self-exchange. Additionally, l-serine selectively inhibited l-alanine self-exchange but barely inhibited l-aspartate self-exchange. The aspartate analogs l-cysteine sulfinic acid, l-cysteic acid, and d-cysteic acid competitively and strongly inhibited l-aspartate self-exchange compared with l-alanine self-exchange. Taken together, these kinetic data suggest that the putative binding sites of l-aspartate and l-alanine are independently located in the substrate translocation pathway of AspT. PMID:21719707

  6. Stability constants of mixed ligand complexes of dioxouranium(II) and thorium(IV) with complexones and isomeric alanines

    International Nuclear Information System (INIS)

    Singh, R.K.; Saxena, M.C.

    1992-01-01

    The present work reports on the stability sequence between UO 2 II and Th IV ions for their mixed ligands complexes with the two isomeric alanines, α-alanine (α-ala) and β-alanine (β-ala) containing a complexone as primary ligand. The complexones used are iminodiacetate (IMDA), nitrilotricetate (NTA), 2-hydroxyethylenediaminetriacetate (HEDTA), ethylenediaminetetraacetate (EDTA), 1,2-diaminocyclohexanetraacetate (CDTA) and diethylenetriminepentaacetate (DTPA). (author). 9 refs., 1 tab

  7. Multifunctional scanning ion conductance microscopy

    Science.gov (United States)

    Page, Ashley; Unwin, Patrick R.

    2017-01-01

    Scanning ion conductance microscopy (SICM) is a nanopipette-based technique that has traditionally been used to image topography or to deliver species to an interface, particularly in a biological setting. This article highlights the recent blossoming of SICM into a technique with a much greater diversity of applications and capability that can be used either standalone, with advanced control (potential–time) functions, or in tandem with other methods. SICM can be used to elucidate functional information about interfaces, such as surface charge density or electrochemical activity (ion fluxes). Using a multi-barrel probe format, SICM-related techniques can be employed to deposit nanoscale three-dimensional structures and further functionality is realized when SICM is combined with scanning electrochemical microscopy (SECM), with simultaneous measurements from a single probe opening up considerable prospects for multifunctional imaging. SICM studies are greatly enhanced by finite-element method modelling for quantitative treatment of issues such as resolution, surface charge and (tip) geometry effects. SICM is particularly applicable to the study of living systems, notably single cells, although applications extend to materials characterization and to new methods of printing and nanofabrication. A more thorough understanding of the electrochemical principles and properties of SICM provides a foundation for significant applications of SICM in electrochemistry and interfacial science. PMID:28484332

  8. Effect of the ionizing radiation on alanine solution for a dosimeter application

    International Nuclear Information System (INIS)

    Ketata, Ameni

    2011-01-01

    The electron spin resonance spectroscopy is well known as a reference and transfer dosimetry system for the evaluation of high doses in radiation processing. The high cost of an EPR/alanine dosimetry system is a serious handicap for large-scale routine application. In this study, the use of irradiated L-alanine dissolved in color indicator solutions (bromothymol blue and fuchsin) was investigated for dosimetry purposes. This solution has an absorbance varies linearly with the absorbed dose in the dose range of 0-25 kGy for the bromothymol blue, and 0-45 kGy for the fuchsin. The effects of the dye and the alanine concentration, the p H value as well as of the solvent have been studied. With respect to routine application, the stability of dosimeters was also investigated

  9. The application of Alanine/ESR dosimetry in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hoon; Lee, Byung Il [Radiation Health Research Institute, Seoul (Korea, Republic of)

    2014-05-15

    Alanine/Electron spin resonance(ESR) has been proven very effective tool which dosimetric characteristics is better suitable than generally used personnel dosimeter for long term dose estimation. L-α-alanine has unusual stability of radiation induced radicals. The fading is known as about 1% a year by IAEA technical documentary. It also has linear signal response on gamma rays over the wide range of dose quantity. Alanine is a kind of unnecessary amino acid in 20 amino acids. Estimation of the accumulated gamma dose is important to predict the life expectancy of cables. However, exact estimation of gamma dose at containment building of NPP is very difficult, because the variability of estimation value is apparently depending on the each installation position in containment building. Especially, some installation positions near reactor change extremely. So, the data from ESR measurement should be checked to the details on referring installation map and pictures.

  10. 14N nuclear quadrupole interaction in Cu(II) doped L-alanine

    International Nuclear Information System (INIS)

    Murgich, J.; Calvo, R.; Oseroff, S.B.; Instituto Venezolano de Investigaciones Cientificas, Caracas. Dept. de Quimica)

    1980-01-01

    The 14 N nuclear quadrupole interaction tensor Psub(N) measured by ENDOR in Cu(II) doped L-alanine is analyzed in terms of the Townes and Daily theory assuming a tetra-hedrally bonded N atom. The results of this analysis are compared with those for the 14 N in pure L-alanine and it is found that the principal directions of the Psub(N) tensor are drastically changed upon metal complexation as a consequence of the higher electron affinity of Cu(II) with respect to C and H. Comparison of the corresponding bond populations in pure and Cu(II) doped L-alanine indicates that the Cu draws 0.11 more electron from the N than the substituted H atom. (orig.)

  11. Structure of alanine racemase from Oenococcus oeni with bound pyridoxal 5′-phosphate

    International Nuclear Information System (INIS)

    Palani, Kandavelu; Burley, Stephen K.; Swaminathan, Subramanyam

    2012-01-01

    Alanine racemase from O. oeni exists as a dimer in the crystal structure. Both monomers contribute to the two active sites present, one for each monomer. The crystal structure of alanine racemase from Oenococcus oeni has been determined at 1.7 Å resolution using the single-wavelength anomalous dispersion (SAD) method and selenium-labelled protein. The protein exists as a symmetric dimer in the crystal, with both protomers contributing to the two active sites. Pyridoxal 5′-phosphate, a cofactor, is bound to each monomer and forms a Schiff base with Lys39. Structural comparison of alanine racemase from O. oeni (Alr) with homologous family members revealed similar domain organization and cofactor binding

  12. Alanine aminotransferase, gamma-glutamyltransferase (GGT) and all-cause mortality: results from a population-based Danish twins study alanine aminotransferase, GGT and mortality in elderly twins

    DEFF Research Database (Denmark)

    Fraser, Abigail; Thinggaard, Mikael; Christensen, Kaare

    2009-01-01

    Abstract Background/Aims: Alanine aminotransferase (ALT) and gamma-glutamyltransferase (GGT) are widely used markers of liver disease. Several population-based cohort studies have found associations of these liver enzymes with all-cause mortality. None of these studies controlled for genetic...... for potential confounders and existing diabetes and cardiovascular disease. Environmental developmental origins may explain the association, but larger twin studies are required to replicate our findings....

  13. Radical formation of irradiated α-alanine and N-acetyl alanine with heavy ion beams. Effects of the irradiation temperature

    International Nuclear Information System (INIS)

    Minegishi, Atsuko; Nagasaki, Jun; Mori, Wasuke; Amano, Chikara; Takagi, Shinji; Murakami, Takeshi; Kanai, Tatsuaki; Furusawa, Yoshiya; Iwata, Yoshiyuki

    2003-01-01

    The characteristics of irradiation with C290 MeV/u ion beams were investigated using X-band electron spin resonance (ESR) spectroscopy for a polycrystalline powder of L-α-alanine at from 77K to 310K. The formed main radicals at 190K∼310K were the deamino radical and the decarboxyl radical. Because of the first-derivative ESR, decarboxyl radical showed an expanded spectral width and a lower peak height because of its amino hydrogen and nitrogen than that of the same amount of deamino radical. The ESR of irradiated L-α-alanine predominantly indicates the spectrum of the deamino radical. On the irradiated, L-α-alanine at from 77K to 310K ESR showed 1:4:6:4:1 lines at 220K and at room temperature, which indicate that the methyl group of the radical was rotating. On the other hand, at 77K ESR the spectrum showed nearly 1:5:5:5:1 lines, like the teeth of a saw, on samples irradiated at 270K∼350K (range IV), and 1:4:6:4:1 lines for those irradiated at 180K∼260K (range II and III), respectively. It is considered that the radical conformation of the deamino radical is planar (most stable conformation) on an irradiated sample in range IV, and a pyramidal structure on the irradiated sample in ranges II and III. (author)

  14. Relative response of the alanine dosimeter to medium energy x-rays.

    Science.gov (United States)

    Anton, M; Büermann, L

    2015-08-07

    The response of the alanine dosimeter to kilovoltage x-rays with respect to the dose to water was measured, relative to the response to Co-60 radiation.Two series of x-ray qualities were investigated, one ranging from 30 kV to 100 kV tube voltage (TW series), the other one ranging from 70 kV to 280 kV (TH series). Due to the use of the water calorimeter as a primary standard, the uncertainty of the delivered dose is significantly lower than for other published data. The alanine response was measured as described in a previous publication (Anton et al 2013 Phys. Med. Biol. 58 3259-82). The uncertainty component due to the alanine measurement and analysis is ⩽0.4%, the major part of the combined uncertainty of the relative response originates from the uncertainty of the delivered dose. The relative uncertainties of the relative response vary from ⩽2% for the TW series to ⩽1.1% for the TH series.Different from the behaviour of the alanine dosimeter for megavoltage x-rays or electrons, the relative response drops significantly from unity for Co-60 radiation to less than 64% for the TW quality with a tube voltage of 30 kV. In order to reproduce this behaviour through Monte Carlo simulations, not only the ratio of the absorbed dose to alanine to the absorbed dose to water has to be known, but also the intrinsic efficiency, i.e. the dependence of the number of free radicals generated per unit of absorbed dose on the photon energy. This quantity is not yet accessible for the TW series.For a possible use of the alanine dosimeter for kilovoltage x-rays, for example in electronic brachytherapy, users should rely on the measured data for the relative response which have become available with this publication.

  15. Synthesis and characterization of alanine boron hydrate for its use in thermal neutron dosimetry

    International Nuclear Information System (INIS)

    Yanez S, J.C.

    1994-01-01

    Alanine boron hydrate was synthesized for its possible use as intercomparison dosimeter for thermal neutron irradiation. The irradiations were performed in the Nuclear Reactor of the Nuclear Center of Mexico. The salt was prepared by reacting alanine and boric acid in a (1:1) stoichiometric ratio in neutral pH 7.5 aqueous solution and also in a basic pH 13 solution. The latter reaction was prepared with the addition of ammonia hydroxide (25%). Solutions were stirred and afterwards were let to evaporate. The obtained product in each reaction is a white solid. Dosimeters were prepared with the obtained reaction products and irradiated under thermal neutron flux of 5 x 10 7 n/cm 2 s. For 30 hours. The analysis of irradiated samples was made in a Variant E-15 Electron Paramagnetic Resonance spectrometer. The observed response of the samples prepared with the reaction product at the basic pH is approximately 50% higher than the neutral pH samples. In order to investigate the optimum signal enhancement samples were prepared in a basic pH medium in the following stoichiometric ratios: (1:0.5); (1:0.75); (1:1.25); (1:1.5) and (1:1.75). It was observed that the samples of the reaction (1:0.75) produced the higher response. The response was 2728% higher than the alanine only dosimeters. The reaction product was chemically characterized by X-ray diffraction, Nuclear Magnetic Resonance, Chromatography, Refractometry and Solubility tests. Results indicate that alanine boron hydrate is formed in basic media and in a stoichiometric ratio (1:0.75). The dosimetric characterization of alanine boron hydrate was performed, results are reported. It is concluded that alanine boron hydrate may be a good intercomparison dosimeter for thermal neutron irradiation. (Author)

  16. L-alanine uptake in membrane vesicles from Mytilus edulis gills

    International Nuclear Information System (INIS)

    Pajor, A.M.; Wright, S.H.

    1986-01-01

    Previous studies have shown that gills from M. edulis can accumulate L-alanine from seawater by a saturable process specific for α-neutral amino acids. This uptake occurs against chemical gradients in excess of 10 6 to 1. To further characterize this uptake, membrane vesicles were prepared from M. edulis gill tissue by differential centrifugation. Enrichments of putative enzyme markers (relative to that in combined initial fractions) were as follows: γ-Glutamyltranspeptidase, 25-30x; Alkaline Phosphatase, 5-6x; K + -dependent para-Nitrophenyl Phosphatase, 3-5x; Succinate Dehydrogenase 0.1-0.2x. These results suggest that the preparation is enriched in plasma membranes, although histochemical studies will be needed to verify this. The time course of 14 C-L-alanine uptake in the presence of inwardly-directed Na + gradient showed a transient overshoot (3-5 fold) at 10 minutes which decreased to equilibrium after six hours. The size of the overshoot and early uptake rates depended on the size of the inwardly-directed Na + gradient. No overshoot was seen in the presence of inwardly-directed gradients of LiCl or choline-Cl, or with equilibrium concentrations NaCl or mannitol. A reduced overshoot was seen with a gradient of NaSCN. A small overshoot was seen with an inwardly-directed gradient of KCl. Transport of L-alanine included saturable and diffusive components. Uptake of 6 μM L-alanine was inhibited more than 80% by 100 μM α-zwitterionic amino acids (alanine, leucine, glycine); by 30 to 75% by proline, aspartate and lysine; and less than 20% by a β-amino acid, taurine. The results of these experiments agree with those from intact gill studies and support the hypothesis that L-alanine is transported into gill epithelial cells by a secondary active transport process involving Na +

  17. A spectrophotometric readout for γ irradiated alanine solution - a dosimetric application

    International Nuclear Information System (INIS)

    Marzouk, Asma

    2007-01-01

    Alanine is a stable dosimeter of reference in its solid state. Its installation in solution as being a dosimetric system of routine remains very useful. A follow-up of the behaviour of the irradiated alanine solution with 15 kGy according to the concentration is carried out by UV-Visible spectrophotometry. The results obtained prove the difficulty in analytical studies of the radiolysis of aqueous solutions by optical absorption due to the ambiguous broad spectra of the species and the reaction products. (Author). 47 refs

  18. The NIM alanine-EPR dosimetry system: its application in NDAS programme and others

    International Nuclear Information System (INIS)

    Gao Jun-Cheng

    1999-01-01

    In 1983, National Institute of Metrology (NIM) began to study alanine-EPR dosimetry system. From 1988 on, the system has been used as a transfer standard to launch into the National Dose Assurance Service (NDAS) programme for cobalt-60 facilities in China. In this paper, the eleven years implementation of NDAS programme are presented by statistics. In 1991, under an IAEA coordinated research programme, NIM had studied to extend the range of the system to therapy level. In recent years, the NIM in cooperation with other institutes has been developing film-alanine dosimeter for electron beam dosimetry. (author)

  19. Effect of combined β-alanine and sodium bicarbonate supplementation on cycling performance.

    Science.gov (United States)

    Bellinger, Phillip M; Howe, Samuel T; Shing, Cecilia M; Fell, James W

    2012-08-01

    The purpose of this study was to investigate the effects of 28 d of β-alanine supplementation on 4-min cycling time trial performance and to determine whether there was an additive effect of combined β-alanine and sodium bicarbonate (NaHCO3) supplementation on high-intensity cycling performance. Fourteen highly trained cyclists (mean ± SD: age = 25.4 ± 7.2 yr, mass = 71.1 ± 7.1 kg, V˙O(2max) = 66.6 ± 5.7 mL·kg·min) supplemented for 28 d with β-alanine (65 mg·kg body mass each day) or placebo. A maximal 4-min bout of cycling was performed before supplementation (baseline) and twice after supplementation: after ingestion of NaHCO3 (300 mg·kg body mass) and ingestion of a placebo using a randomized crossover design with 2 d between trials. Blood pH and HCO3 concentration were determined before loading (postsupplementation trials) and at pretest and posttest. In the acute NaHCO3 loading trials, blood pH and HCO3 were elevated from before loading to pretest, and the magnitude of the change in HCO3 from pretest to posttest was significantly greater compared with the acute placebo loading trial (P < 0.001). Average power output in the 4-min cycling performance trial was increased in placebo + NaHCO3 (+3.1% ± 1.8%) and β-alanine + NaHCO3 (+3.3% ± 3.0%) compared with baseline (P < 0.05). β-alanine + placebo did not significantly improve average power output compared with baseline (+1.6% ± 1.7%, P = 0.20); however, magnitude-based inferences demonstrated that β-alanine + placebo was associated with a 37% likelihood of producing average power improvements. In trained cyclists, β-alanine supplementation did not significantly improve 4-min cycling performance; however, there may be a small meaningful improvement in performance. Acute NaHCO3 supplementation significantly improved 4-min cycling performance. There seemed to be a minimal additive effect of combined β-alanine and NaHCO3 supplementation.

  20. Development of a dosimeter for high doses assessment based on Alanine/EPR

    International Nuclear Information System (INIS)

    Galante, O.L.; Rodrigues, O. Jr.; Campos, L.L.

    2000-01-01

    The increasing use of radiation sources of high activity for industrial and medical applications becomes important the research and the development of detectors and dosimetric methods for quality control of the applied doses. This work presents the current stage of the research at IPEN/CNEN-SP that has as objective the development of a standard dosimetric system for high doses assessment based on the alanine as radiation detector and electron paramagnetic resonance (EPR) as measurement technique. The developed system consists of the cylindrical container built in polyethylene of high density and the detector element based on DL-alanine commercially available. For the detector preparation different binding materials such as paraffin and acetate polyvinyl solution (pva) and also the use of a polyethylene tube of low density with 3.2 mm of external diameter, 2 mm of internal diameter and 30 mm of length were tested to provide the easier preparation method and the most sensitive detector. For the alanine + paraffin detector it was used 80% of alanine and 20% of paraffin, for the alanine + pva detector it was used 70% of alanine and 30% of pva solution, and pure alanine was encapsulated, compacted and sealed in the case of the polyethylene tube. The obtained results with respect to handling, packing and construction easiness showed that the polyethylene tube presents all characteristics to obtain of a good detector element. The validation of the dosimetric system was carried out with gamma radiation of the cobalt-60 with doses in the range between 0.2 Gy to 200 kGy. Type tests such as fading, lowest detection limit, reproducibility and energy dependence of the sign EPR were performed. All measurements were carried out at room temperature using a spectrometer of electron paramagnetic resonance (EPR) Bruker model MXE. Taking into account the results obtained: linearity of the EPR signal between 10 Gy and 50 kGy, reproducibility better than 3%, low fading associated with

  1. The photon energy dependence of the alanine/EPR dosimetry system, an experimental investigation

    International Nuclear Information System (INIS)

    Bergstrand, E.S.; Hole, E.O.; Shortt, K.R.; Ross, C.K.

    2002-01-01

    The energy dependence of a dosimetry system based on electron paramagnetic resonance (EPR) spectroscopy of alanine has been studied to determine its suitability for use in dose verification for radiotherapy. A few experiments with high-energy photon irradiation of alanine have been reported in the literature. However, the reported results disagree whether the ratio of dose in alanine to dose in water is independent of the radiation energy or whether there is a small dependence for photon energies of relevance to radiotherapy. The concentration of free radicals in alanine is proportional to the absorbed dose in alanine over a wide dose range covering three decades. The relative number of radicals may be determined by examining the EPR spectrum, and hence it is possible to determine the dose with a system that has been calibrated using a known dose of 60 Co radiation. In the present work, irradiations of alanine dosimeters were performed at the National Research Council (NRC), in Ottawa, Canada. The radiation qualities investigated were 10, 20 and 30 MV x-rays using the NRC linac. For each radiation quality, 30 dosimeters were irradiated in a water phantom with a level of absorbed dose to water ranging from 10 to 50 Gy. For reference purposes, irradiations using the NRC 60 Co source were performed on more or less the same day as the irradiations at each specific linac quality. In all beams, the dose to water was measured using a graphite-walled NE2571 ionisation chamber that was originally calibrated by comparison with a sealed-water calorimeter. The alanine dosimeters were evaluated at the EPR laboratory at the University of Oslo, Norway, using an X-band Bruker ESP300E spectrometer with a rectangular double resonator. One of the resonators contained a Mn 2+ /MgO sample that was read after each dosimeter reading, in order to provide independence from short-term sensitivity fluctuations in the spectrometer. All dosimeters irradiated at one specific linac quality were

  2. An investigation of the photon energy dependence of the EPR alanine dosimetry system

    International Nuclear Information System (INIS)

    Bergstrand, Eva Stabell; Shortt, Ken R; Ross, Carl K; Hole, Eli Olaug

    2003-01-01

    The electron paramagnetic resonance (EPR) alanine dosimetry system is based on EPR measurements of radicals formed in alanine by ionizing radiation. The system has been studied to determine its energy dependence for photons in the 10-30 MV region relative to those of 60 Co and to find out if the system would be suitable for dosimetry comparisons. The irradiations were carried out at the National Research Council, Ottawa, Canada and the doses ranged from 8 to 54 Gy. The EPR measurements were performed at the University of Oslo, Norway. The ratio of the slope of the alanine reading versus dose-to-water curve for a certain linac photon beam quality and the corresponding slope for a reference 60 Co γ-radiation gives an experimental measure of the relative dose-to-water response of the EPR alanine dosimetry system. For calculating the linear regression coefficients of these alanine reading versus dose curves, the method of weighted least squares was used. This method is assumed to produce more accurate regression coefficients when applied to EPR dosimetry than the common method of standard least squares. The overall uncertainty on the ratio of slopes was between 0.5 and 0.6% for all three linac energies. The relative response for all the linac beams compared to cobalt was less than unity: by about 0.5% for the 20 and 30 MV points but by more than 1% for the 10 MV point. The given standard uncertainties negate concluding that there is any significant internal variation in the measured response as a function of beam quality between the three linac energies. Thus, we calculated the average dose response for all three energies and found that the alanine response is 0.8% (±0.5%) lower for high energy x-rays than for 60 Co γ-rays. This result indicates a small energy dependence in the alanine response for the high-energy photons relative to 60 Co which may be significant. This result is specific to our dosimetry system (alanine with 20% polyethylene binder pressed into a

  3. Oxidation of phenyl alanine by pyridinium chlorochromate in acidic DMF–water medium: A kinetic study

    Directory of Open Access Journals (Sweden)

    B.L. Hiran

    2016-11-01

    Full Text Available The kinetics of oxidation of phenyl alanine by pyridinium chlorochromate in DMF–water (70:30% mixture in presence of perchloric acid leads to the formation of corresponding aldehyde. The reaction is of first order each in [PCC], [HClO4] and [AA]. Michaelis–Menten type kinetics was observed with phenyl alanine. The reaction rates were determined at different temperatures [25, 30, 35, 40, 45, 50 °C] and the activation parameters were calculated. The reaction does not induce polymerization of acrylonitrile. With an increase in the amount of DMF in its aqueous mixture, the rate increases. A suitable mechanism for the reaction was postulated.

  4. Interfaces habladas

    Directory of Open Access Journals (Sweden)

    María Teresa Soto Sanfiel

    2012-04-01

    Full Text Available Este artículo describe y piensa al fenómeno de las Interfaces habladas (IH desde variados puntos de vista y niveles de análisis. El texto se ha concebido con los objetivos específicos de: 1.- procurar una visión panorámica de aspectos de la producción y consumo comunicativo de las IH; 2.- ofrecer recomendaciones para su creación y uso eficaz, y 3.- llamar la atención sobre su proliferación e inspirar su estudio desde la comunicación. A pesar de la creciente presencia de las IF en nues-tras vidas cotidianas, hay ausencia de textos que las caractericen y analicen por sus aspectos comunicativos. El trabajo es pertinente porque el fenómeno significa un cambio respecto a estadios comunica-tivos precedentes con consecuencias en las concepciones intelectuales y emocionales de los usuarios. La proliferación de IH nos abre a nue-vas realidades comunicativas: hablamos con máquinas.

  5. Radiopharmaceutical scanning agents

    International Nuclear Information System (INIS)

    1976-01-01

    This invention is directed to dispersions useful in preparing radiopharmaceutical scanning agents, to technetium labelled dispersions, to methods for preparing such dispersions and to their use as scanning agents

  6. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Scan and Uptake Thyroid scan and uptake uses small amounts of radioactive materials called radiotracers, a special ... is a branch of medical imaging that uses small amounts of radioactive material to diagnose and determine ...

  7. Nuclear Heart Scan

    Science.gov (United States)

    ... Home / Nuclear Heart Scan Nuclear Heart Scan Also known as Nuclear Stress Test , ... Learn More Connect With Us Contact Us Directly Policies Privacy Policy Freedom of Information Act (FOIA) Accessibility ...

  8. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... of page What will I experience during and after the procedure? Most thyroid scan and thyroid uptake ... you otherwise, you may resume your normal activities after your nuclear medicine scan. If any special instructions ...

  9. RBC nuclear scan

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003835.htm RBC nuclear scan To use the sharing features on this page, please enable JavaScript. An RBC nuclear scan uses small amounts of radioactive material to ...

  10. Scanning gamma camera

    International Nuclear Information System (INIS)

    Engdahl, L.W.; Batter, J.F. Jr.; Stout, K.J.

    1977-01-01

    A scanning system for a gamma camera providing for the overlapping of adjacent scan paths is described. A collimator mask having tapered edges provides for a graduated reduction in intensity of radiation received by a detector thereof, the reduction in intensity being graduated in a direction normal to the scanning path to provide a blending of images of adjacent scan paths. 31 claims, 15 figures

  11. Prediction of hot spot residues at protein-protein interfaces by combining machine learning and energy-based methods

    Directory of Open Access Journals (Sweden)

    Pontil Massimiliano

    2009-10-01

    Full Text Available Abstract Background Alanine scanning mutagenesis is a powerful experimental methodology for investigating the structural and energetic characteristics of protein complexes. Individual amino-acids are systematically mutated to alanine and changes in free energy of binding (ΔΔG measured. Several experiments have shown that protein-protein interactions are critically dependent on just a few residues ("hot spots" at the interface. Hot spots make a dominant contribution to the free energy of binding and if mutated they can disrupt the interaction. As mutagenesis studies require significant experimental efforts, there is a need for accurate and reliable computational methods. Such methods would also add to our understanding of the determinants of affinity and specificity in protein-protein recognition. Results We present a novel computational strategy to identify hot spot residues, given the structure of a complex. We consider the basic energetic terms that contribute to hot spot interactions, i.e. van der Waals potentials, solvation energy, hydrogen bonds and Coulomb electrostatics. We treat them as input features and use machine learning algorithms such as Support Vector Machines and Gaussian Processes to optimally combine and integrate them, based on a set of training examples of alanine mutations. We show that our approach is effective in predicting hot spots and it compares favourably to other available methods. In particular we find the best performances using Transductive Support Vector Machines, a semi-supervised learning scheme. When hot spots are defined as those residues for which ΔΔG ≥ 2 kcal/mol, our method achieves a precision and a recall respectively of 56% and 65%. Conclusion We have developed an hybrid scheme in which energy terms are used as input features of machine learning models. This strategy combines the strengths of machine learning and energy-based methods. Although so far these two types of approaches have mainly been

  12. Whole body scan system based on γ camera

    International Nuclear Information System (INIS)

    Ma Tianyu; Jin Yongjie

    2001-01-01

    Most existing domestic γ cameras can not perform whole body scan protocol, which is of important use in clinic. The authors designed a set of whole body scan system, which is made up of a scan bed, an ISA interface card controlling the scan bed and the data acquisition software based on a data acquisition and image processing system for γ cameras. The image was obtained in clinical experiment, and the authors think it meets the need of clinical diagnosis. Application of this system in γ cameras can provide whole body scan function at low cost

  13. Recent progress in application of JAERI alanine/ESR dosimetry system

    International Nuclear Information System (INIS)

    Kojima, T.

    1995-01-01

    Feasibility studies of application of JAERI alanine/ESR dosimetry system were performed on radiotherapy level dosimetry, low dose-rate dosimetry for residual life estimation of cable insulators used in nuclear power facilities, and dose monitoring for electron processing. (author)

  14. Electronic structure and first hyperpolarizability of poly (μ2-L-alanine ...

    Indian Academy of Sciences (India)

    Poly(2-L-alanine-3-sodium nitrate (I)), -LASN, crystals have been grown by slow evaporation at room temperature. The nominal size of the crystals obtained by the method was of 500 nm. The UV–Vis spectrum shows a wide range, where absorption is lacking around 532 nm, which is required in order to have the ...

  15. Liver alanine aminotransferase, insulin resistance and endothelial dysfunction in normotriglyceridaemic subjects with type 2 diabetes mellitus

    NARCIS (Netherlands)

    Schindhelm, RK; Diamant, M; Bakker, SJL; van Dijk, RAJM; Scheffer, PG; Teerlink, T; Kostense, PJ; Heine, RJ

    Background Plasma levels of liver transaminases, including alanine aminotransferase (ALT), are elevated in most cases of nonalcoholic fatty liver disease (NAFLD). Elevated ALT levels are associated with insulin resistance, and subjects with NAFLD have features of the metabolic syndrome that confer

  16. Alanine aminotransferase and mortality in patients with type 2 diabetes (ZODIAC-38)

    NARCIS (Netherlands)

    Deetman, Petronella E.; Alkhalaf, Alaa; Landman, Gijs W. D.; Groenier, Klaas H.; Kootstra-Ros, Jenny E.; Navis, Gerjan; Bilo, Henk J. G.; Kleefstra, Nanne; Bakker, Stephan J. L.

    Introduction Combined data suggest a bimodal association of alanine aminotransferase (ALT) with mortality in the general population. Little is known about the association of ALT with mortality in patients with type 2 diabetes. We therefore investigated the association of ALT with all-cause,

  17. Liver alanine aminotransferase, insulin resistance and endothelial dysfunction in normotriglyceridaemic subjects with type 2 diabetes mellitus

    NARCIS (Netherlands)

    Schindhelm, R.K.; Diamant, M.; Bakker, S.J.L.; van Dijk, R.A.; Scheffer, P.G.; Teerlink, T.; Kostense, P.J.; Heine, R.J.

    2005-01-01

    Background: Plasma levels of liver transaminases, including alanine aminotransferase (ALT), are elevated in most cases of nonalcoholic fatty liver disease (NAFLD). Elevated ALT levels are associated with insulin resistance, and subjects with NAFLD have features of the metabolic syndrome that confer

  18. Selfcalibrated alanine/EPR dosimeters. A new generation of solid state/EPR dosimeters

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    1999-01-01

    Alanine/EPR dosimeters are well established as secondary, reference dosimeters for high-energy radiation. However, there are various sources of uncertainty in the evaluation of absorbed dose. This arises primarily from the necessity to calibrate each EPR spectrometer and each batch of dosimeters before their use. In order to overcome this disadvantage, a new generation alanine/EPR dosimeter has been developed, and its possibilities as a radiation detector are reported. Principally, it is a mixture of alanine, some quantity of EPR active substance, and a binding material. The EPR active substance, acting as an internal EPR standard, is chosen to have EPR parameters which are independent of the irradiation dose. The simultaneous recording of the spectra of both the sample and the standard under the same experimental conditions and the estimation of the ratio I alanine /I Mn as a function of the absorbed dose strongly reduces the uncertainties. The response of these dosimeters for 60 Co γ-radiation exhibits excellent linearity and reproducibility in the range of absorbed dose, 10 2 - 5 x 10 4 Gy. (author)

  19. Spectrophotometric readout for alanine dosimeter to be used for food irradiation applications

    International Nuclear Information System (INIS)

    Ebraheem, S.; Beshir, W.B.; Eid, S.

    2002-01-01

    The electron spin resonance (EPR) readout of radical concentration produced upon irradiation of L-alanine is well known as a transfer dosimetry system for high dose level. The highly cost of EPR/alanine dosimetry system is a serious handicap for large scale routine application to be used in irradiation facilities. In this study, the reaction between L-alanine and 1,4-phenyl diammonium dichloride (PAC) solution produces a complex has a purple color. This complex has a variable absorbance with applied doses in the range from 1-20 kGy. Spectrophotometric evaluation at 368 and 505 nm for the absorbance intensity of this color as well as fluorimetric emission wavelength 435 nm were investigated, as a function of dose. The used method is uncomplicated and very easy for routine application. Evaluation of the dye concentration and the suitable amount of alanine has been studied. Stability of the product complex, for long period of time after the reaction had taken place, was also investigated

  20. Spectrophotometric readout for alanine dosimeter to be used for food irradiation applications

    International Nuclear Information System (INIS)

    Ebraheem, S.; Beshir, W.B.; Sobhy, R.; Kovacs, A.; Wojnarovits, L.

    2002-01-01

    Complete text of publication follows. The electron spin resonance (EPR) readout of radical concentration produced upon irradiation of L-alanine is well known as a transfer dosimetry system for high dose range. The high cost of EPR/alanine dosimetry system is a serious handicap for large-scale routine application for use in irradiation facilities. In this study the irradiated L-alanine was dissolved in 1,4 -phenyl diammonium dichloride (PAC) solution resulting a complex of a purple colour. This complex has a variable absorbance with applied dose in the range from 1 - 20 kGy. The absorbance of this complex using spectrophotometric evaluation was investigated at 401 and 478 nm with increasing dose. The fluorimetric emission was also studied at the wavelength of 475 nm as a function of dose. This methos for dose evaluation is uncomplicated and very easy for routine application. The effect of the dye concentration as well as the suitable amount of alanine has been studied with respect to practical use. The stability of the complex for long period of time was also investigated

  1. Inhibitory effect of different product analogues on {beta}-alanine synthase: A thermodynamic and fluorescence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Andujar-Sanchez, Montserrat; Martinez-Gomez, Ana Isabel; Martinez-Rodriguez, Sergio; Clemente-Jimenez, Josefa Maria; Heras-Vazquez, Francisco Javier Las; Rodriguez-Vico, Felipe [Departamento de Quimica Fisica, Bioquimica y Quimica Inorganica, Facultad de Ciencias Experimentales, Universidad de Almeria, Carretera de Sacramento s/n, La Canada de San Urbano, Almeria 04120 (Spain); Jara-Perez, Vicente [Departamento de Quimica Fisica, Bioquimica y Quimica Inorganica, Facultad de Ciencias Experimentales, Universidad de Almeria, Carretera de Sacramento s/n, La Canada de San Urbano, Almeria 04120 (Spain)], E-mail: vjara@ual.es

    2009-02-15

    The enzyme N-carbamoyl-{beta}-alanine amidohydrolase catalyse the hydrolysis of N-carbamoyl-{beta}-alanine or N-carbamoyl-{beta}-aminoisobutyric acid to {beta}-alanine or 3-aminoisobutyric acid, under the release of carbon-dioxide and ammonia. This work studies the inhibition of N-carbamoyl-{beta}-alanine amidohydrolase from Agrobacterium tumefaciens C58 (At{beta}car) by different carboxylic acid compounds that differ in number of carbons, and position and size of ramification, while the binding thermodynamics of the inhibitors are studied by isothermal titration calorimetry (ITC) and fluorescence. From the binding constants and inhibition studies, we conclude that propionate is the most efficient inhibitor among those tested. Substitution of the linear alkyl acids in positions 2 and 3 resulted in a drastic decrease of the affinity. The thermodynamic parameters show that a conformational change is triggered upon ligand binding. Binding enthalpy {delta}H{sub b} is negative in all cases for all ligands, and thus, Van der Waals interactions and hydrogen bonding are most probably the major sources for this term. The process is entropically favoured at all temperatures and pH studied, most probably due to the liberation of water molecules accompanying the conformational change of the enzyme.

  2. Fluoropolymer coated alanine films treated by atmospheric pressure plasmas − In comparison with gamma irradiation

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Bardenshtein, Alexander; Morgen, Per

    2018-01-01

    Fluoropolymer coated alanine films are treated by a dielectric barrier discharge and a gliding arc at atmospheric pressure as well as with gamma irradiation. The film surfaces and the underlying bulk materials are characterized before and after each treatment. The fluorine content decreases...

  3. Different β-alanine dimeric forms in trifluoromethanesulfonic acid salts. XRD and vibrational studies.

    Science.gov (United States)

    Wołoszyn, Łukasz; Ilczyszyn, Maria M

    2018-03-15

    Two new crystalline salts: β-alaninium trifluoromethanesulfonate (β-AlaOTf) and bis(β-alanine) trifluoromethanesulfonate (β-2AlaOTf) were obtained. The former one contains diprotonated β-alanine dimer, the latter one monoprotonated β-alanine dimer. Both compounds were studied by single crystal XRD, vibrational (IR and Raman) spectroscopy and calorimetric method. The quantum-mechanical calculations (DFT/B3LYP/6-311++G(2d,2p)) for the diprotonated dimer were carried out. The β-AlaOTf salt crystallizes in the P1¯ space group of triclinic system (Z=2), the β-2AlaOTf in the P2 1 /m space group of monoclinic system (Z=2). The vibrational data for the studied compounds are discussed in relation to their crystal structure, and provide insight into the character of hydrogen bonds and β-alanine protonation. The studied crystals do not exhibit phase transitions in the solid state. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Advancements in accuracy of the alanine dosimetry system. Part 1. The effects of environmental humidity

    International Nuclear Information System (INIS)

    Sleptchonok, Olga F.; Nagy, Vitaly; Desrosiers, Marc F.

    2000-01-01

    A one-year study of the EPR signal of γ-irradiated ( 60 Co) L-α-alanine with simultaneous monitoring of the cavity Q-factor was undertaken. The widespread opinion that the EPR signal remains absolutely stable under normal laboratory storage conditions is inaccurate. At 0% humidity, the signal can be regarded as stable within ±1% of its initial value for 6 months for 1 and 10 kGy doses, but for only 3 months for 100 kGy. When stored at the same relative humidity values up to 60%, the fading rates for dosimeters irradiated to 1 and 10 kGy are similar, whereas signals of dosimeters irradiated to 100 kGy fade considerably faster for all humidities. The rates of fading increase with the relative humidity, especially above 60% R. H. Environmental humidity also deteriorates the accuracy of alanine dosimetry by changing the resonant cavity Q-factor. This is particularly important when irradiated alanine dosimeters are used as instrument calibration standards. Short-term changes in alanine EPR signal amplitudes were recorded upon removal of the irradiated dosimeters from their storage environments. The importance of an in situ standard to correct for measurement errors due to environmental effects is demonstrated. (author)

  5. High-pressure X-ray diffraction of L-ALANINE crystal

    DEFF Research Database (Denmark)

    Olsen, J.S.; Gerward, Leif; Souza, A.G.

    2006-01-01

    L-ALANINE has been studied by X-ray diffraction at ambient temperature and pressure up to 10.3 GPa. The material is found to transform to a tetragonal structure between 2 and 3 GPa. and to a monoclinic structure between 8 and 10 GPa. The experimental bulk modulus is 25(5) GPa for the orthorhombic...

  6. Autolysis of Lactococcus lactis is increased upon D-alanine depletion of peptidoglycan and lipoteichoic acids

    NARCIS (Netherlands)

    Steen, Anton; Palumbo, Emmanuelle; Deghorain, Marie; Cocconcelli, Pier Sandro; Delcour, Jean; Kuipers, Oscar P.; Kok, Jan; Buist, Girbe; Hols, Pascal

    Mutations in the genes encoding enzymes responsible for the incorporation of D-Ala into the cell wall of Lactococcus lactis affect autolysis. An L. lactis alanine racemase (alr) mutant is strictly dependent on an external Supply Of D-Ala to be able to synthesize peptidoglycan and to incorporate

  7. Role of the gerA operon in L-alanine germination of Bacillus licheniformis spores

    Directory of Open Access Journals (Sweden)

    Løvdal Irene S

    2012-03-01

    Full Text Available Abstract Background The genome of Bacillus licheniformis DSM 13 harbours three neighbouring open reading frames showing protein sequence similarities to the proteins encoded from the Bacillus subtilis subsp. subtilis 168 gerA operon, GerAA, GerAB and GerAC. In B. subtilis, these proteins are assumed to form a germinant receptor involved in spore germination induced by the amino acid L-alanine. Results In this study we show that disruption of the gerAA gene in B. licheniformis MW3 hamper L-alanine and casein hydrolysate-triggered spore germination, measured by absorbance at 600 nm and confirmed by phase contrast microscopy. This ability was restored by complementation with a plasmid-borne copy of the gerA locus. Addition of D-alanine in the casein hydrolysate germination assay abolished germination of both B. licheniformis MW3 and the complementation mutant. Germination of both B. licheniformis MW3 and the gerA disruption mutant was induced by the non-nutrient germinant Ca2+-Dipicolinic acid. Conclusions These results demonstrate that the B. licheniformis MW3 gerA locus is involved in germination induced by L-alanine and potentially other components present in casein hydrolysate.

  8. Role of the gerA operon in L-alanine germination of Bacillus licheniformis spores

    Science.gov (United States)

    2012-01-01

    Background The genome of Bacillus licheniformis DSM 13 harbours three neighbouring open reading frames showing protein sequence similarities to the proteins encoded from the Bacillus subtilis subsp. subtilis 168 gerA operon, GerAA, GerAB and GerAC. In B. subtilis, these proteins are assumed to form a germinant receptor involved in spore germination induced by the amino acid L-alanine. Results In this study we show that disruption of the gerAA gene in B. licheniformis MW3 hamper L-alanine and casein hydrolysate-triggered spore germination, measured by absorbance at 600 nm and confirmed by phase contrast microscopy. This ability was restored by complementation with a plasmid-borne copy of the gerA locus. Addition of D-alanine in the casein hydrolysate germination assay abolished germination of both B. licheniformis MW3 and the complementation mutant. Germination of both B. licheniformis MW3 and the gerA disruption mutant was induced by the non-nutrient germinant Ca2+-Dipicolinic acid. Conclusions These results demonstrate that the B. licheniformis MW3 gerA locus is involved in germination induced by L-alanine and potentially other components present in casein hydrolysate. PMID:22420404

  9. Inhibitory effect of different product analogues on β-alanine synthase: A thermodynamic and fluorescence analysis

    International Nuclear Information System (INIS)

    Andujar-Sanchez, Montserrat; Martinez-Gomez, Ana Isabel; Martinez-Rodriguez, Sergio; Clemente-Jimenez, Josefa Maria; Heras-Vazquez, Francisco Javier Las; Rodriguez-Vico, Felipe; Jara-Perez, Vicente

    2009-01-01

    The enzyme N-carbamoyl-β-alanine amidohydrolase catalyse the hydrolysis of N-carbamoyl-β-alanine or N-carbamoyl-β-aminoisobutyric acid to β-alanine or 3-aminoisobutyric acid, under the release of carbon-dioxide and ammonia. This work studies the inhibition of N-carbamoyl-β-alanine amidohydrolase from Agrobacterium tumefaciens C58 (Atβcar) by different carboxylic acid compounds that differ in number of carbons, and position and size of ramification, while the binding thermodynamics of the inhibitors are studied by isothermal titration calorimetry (ITC) and fluorescence. From the binding constants and inhibition studies, we conclude that propionate is the most efficient inhibitor among those tested. Substitution of the linear alkyl acids in positions 2 and 3 resulted in a drastic decrease of the affinity. The thermodynamic parameters show that a conformational change is triggered upon ligand binding. Binding enthalpy ΔH b is negative in all cases for all ligands, and thus, Van der Waals interactions and hydrogen bonding are most probably the major sources for this term. The process is entropically favoured at all temperatures and pH studied, most probably due to the liberation of water molecules accompanying the conformational change of the enzyme

  10. Protein Homeostasis Defects of Alanine-Glyoxylate Aminotransferase: New Therapeutic Strategies in Primary Hyperoxaluria Type I

    Directory of Open Access Journals (Sweden)

    Angel L. Pey

    2013-01-01

    Full Text Available Alanine-glyoxylate aminotransferase catalyzes the transamination between L-alanine and glyoxylate to produce pyruvate and glycine using pyridoxal 5′-phosphate (PLP as cofactor. Human alanine-glyoxylate aminotransferase is a peroxisomal enzyme expressed in the hepatocytes, the main site of glyoxylate detoxification. Its deficit causes primary hyperoxaluria type I, a rare but severe inborn error of metabolism. Single amino acid changes are the main type of mutation causing this disease, and considerable effort has been dedicated to the understanding of the molecular consequences of such missense mutations. In this review, we summarize the role of protein homeostasis in the basic mechanisms of primary hyperoxaluria. Intrinsic physicochemical properties of polypeptide chains such as thermodynamic stability, folding, unfolding, and misfolding rates as well as the interaction of different folding states with protein homeostasis networks are essential to understand this disease. The view presented has important implications for the development of new therapeutic strategies based on targeting specific elements of alanine-glyoxylate aminotransferase homeostasis.

  11. [Establishing biological reference intervals of alanine transaminase for clinical laboratory stored database].

    Science.gov (United States)

    Guo, Wei; Song, Binbin; Shen, Junfei; Wu, Jiong; Zhang, Chunyan; Wang, Beili; Pan, Baishen

    2015-08-25

    To establish an indirect reference interval based on the test results of alanine aminotransferase stored in a laboratory information system. All alanine aminotransferase results were included for outpatients and physical examinations that were stored in the laboratory information system of Zhongshan Hospital during 2014. The original data were transformed using a Box-Cox transformation to obtain an approximate normal distribution. Outliers were identified and omitted using the Chauvenet and Tukey methods. The indirect reference intervals were obtained by simultaneously applying nonparametric and Hoffmann methods. The reference change value was selected to determine the statistical significance of the observed differences between the calculated and published reference intervals. The indirect reference intervals for alanine aminotransferase of all groups were 12 to 41 U/L (male, outpatient), 12 to 48 U/L (male, physical examination), 9 to 32 U/L (female, outpatient), and 8 to 35 U/L (female, physical examination), respectively. The absolute differences when compared with the direct results were all smaller than the reference change value of alanine aminotransferase. The Box-Cox transformation combined with the Hoffmann and Tukey methods is a simple and reliable technique that should be promoted and used by clinical laboratories.

  12. On the fragmentation of biomolecules: fragmentation of alanine dipeptide along the polypeptide chain

    DEFF Research Database (Denmark)

    Solov'yov, Ilia; Yakubovich, Alexander; Solov'yov, Andrey

    2006-01-01

    The interaction potential between amino acids in alanine dipeptide has been studied for the first time taking into account exact molecular geometry. Ab initio calculation has been performed in the framework of density functional theory taking into account all electrons in the system. The fragment...

  13. Study of EPR spectra of radicals from ionizing radiation interaction with alanine and 4-hydroxyproline samples

    International Nuclear Information System (INIS)

    Simion, Corina Anca; Georgescu, Rodica; Grigorescu, Eric Leon

    2006-01-01

    A number of stable chemical radicals result following irradiation with ionizing rays of α-β-alanine and 4-hydroxyproline. They could be put into evidence using post-irradiation EPR technique. Analysis and inter-comparison of spectra signals become important for a correct assignment of structure and, subsequently of generating mechanisms in amino acids irradiated samples. (author)

  14. Influence of the irradiation temperature on the free-radical response of alanine

    International Nuclear Information System (INIS)

    Wieser, A.; Siegele, R.; Regulla, D.F.

    1989-01-01

    GSF operates the only IAEA high-level dosimetry reference laboratory and, as a joint project with the IAEA, the International Dose Assurance Service (IDAS). Dosimetry is based on long-lived free radicals in organic alanine induced by ionizing radiation and readout by ESR spectroscopy. The thermal time response of the radical concentration in alanine is fairly constant after irradiation provided that the alanine samples are stored at temperatures below 50 0 C. By contrast, a positive temperature coefficient had earlier been found at GSF for the production rate of alanine radicals, for irradiation temperatures between 0 and 50 0 C. This effect has to be considered for reference dosimetry in radiation processing. Radiation processing is also of interest at irradiation temperatures below 0 0 C. The present study describes experiments on the influence of irradiation temperatures between +50 and -100 0 C. Comparison is made between the present and earlier results, in the overlapping temperature range. An empirical function is proposed for the temperature coefficient based on the experimental data. (author)

  15. Effect of chronic renal failure with metabolic acidosis on alanine metabolism in isolated liver cells

    NARCIS (Netherlands)

    Cano, N.; Sturm, J. M.; Meijer, A. J.; El-Mir, M. Y.; Novaretti, R.; Reynier, J. P.; Leverve, X. M.

    2004-01-01

    Background Et aims: Decreased ureagenesis and gluconeogenesis from atanine have been reported during chronic renal failure in rat. This study addressed the respective roles of plasma-membrane transport and intracellular metabolism in these abnormalities of alanine pathways. Methods: In hepatocytes

  16. Beta-alanine/alpha-ketoglutarate aminotransferase for 3-hydroxypropionic acid production

    Science.gov (United States)

    Jessen, Holly Jean [Chanhassen, MN; Liao, Hans H [Eden Prairie, MN; Gort, Steven John [Apple Valley, MN; Selifonova, Olga V [Plymouth, MN

    2011-10-04

    The present disclosure provides novel beta-alanine/alpha ketoglutarate aminotransferase nucleic acid and protein sequences having increased biological activity. Also provided are cells containing such enzymes, as well as methods of their use, for example to produce malonyl semialdehyde and downstream products thereof, such as 3-hydroxypropionic acid and derivatives thereof.

  17. The VA and VCD spectra of various isotopomers of L-alanine in aqueous solution

    DEFF Research Database (Denmark)

    Abdali, Salim; Jalkanen, Karl J.; Bohr, Henrik

    2002-01-01

    Density functional theory (DFT) at the Becke 3LYP level has been used to calculate the vibrational absorption (VA) and vibrational circular dichroism (VCD) spectra of various deuterated species Of L-alanine. The effect of replacing the methine hydrogen, CH1, the methyl group, CH3, and both...

  18. Effect of alpha interferon on glucose and alanine transport by rat renal brush border membrane vesicles

    International Nuclear Information System (INIS)

    Batuman, V.; Chadha, I.

    1990-01-01

    To investigate the pathogenetic mechanisms of interferon nephrotoxicity, we studied the effect of recombinant interferon alfa-2b on the uptake of 14 C-D-glucose and 14 C-L-alanine by rat renal brush-border-membrane vesicles. Interferon significantly inhibited 20 sec. sodium-dependent and 5 and 10 min. equilibrium uptake of both glucose and alanine. The inhibitory effect was dose dependent with maximum effect achieved at interferon concentration of 5 x 10 -8 M in the uptake media. The half-maximal inhibitory concentrations, IC 50 , of interferon on glucose uptake was 1.8 x 10 -8 M, and 5.4 x 10 -9 M on alanine uptake. Dixon plot analysis of uptake data was consistent with pure non-competitive inhibition. The inhibition constants, K i , 1.5 x 10 -8 M for glucose uptake, and 7.3 x 10 -9 M for alanine uptake, derived from Dixon plots were in close agreement with the IC 50 s calculated from the semilog dose response curves. These observations reveal that direct interactions at the proximal tubule cell membrane are involved in the pathogenesis of interferon nephrotoxicity, and that its mechanism of nephrotoxicity is similar to that of other low molecular weight proteins

  19. Kinetic enantioselectivity of a protonated bis(diamido)-bridged basket resorcin[4]arene towards alanine peptides.

    Science.gov (United States)

    Fraschetti, C; Montagna, M; Crestoni, M E; Calcaterra, A; Aiello, F; Santi, L; Filippi, A

    2017-02-01

    Efficient enantiodiscrimination of some alanine-containing di- and tri-peptides by using chiral protonated bis(diamido)-bridged basket resorcin[4]arenes depends on several factors, including the basicity of the amino acid residues at the C- and N-termini of the peptide.

  20. Weight loss and elevated gluconeogenesis from alanine in lung cancer patients

    NARCIS (Netherlands)

    S. Leij-Halfwerk (Susanne); P.C. Dagnelie (Pieter); J.W.O. van den Berg (Willem); J.L.D. Wattimena (Josias); C.H. Hordijk-Luijk; J.H.P. Wilson (Paul)

    2000-01-01

    textabstractBACKGROUND: The role of gluconeogenesis from protein in the pathogenesis of weight loss in lung cancer is unclear. OBJECTIVE: Our aim was to study gluconeogenesis from alanine in lung cancer patients and to analyze its relation to the degree of weight loss.

  1. Electron paramagnetic resonance radiation dosimetry: possible inorganic alternatives to the EPR/alanine dosimeter

    International Nuclear Information System (INIS)

    Keizer, P.N.; Morton, J.R.; Preston, K.F.

    1991-01-01

    The intensity of the EPR spectrum of γ-irradiated L-α-alanine has been accepted by the International Atomic Energy Agency as a secondary standard for high-dose (10-100 000 Gy) dosimetry. The alanine dosimeter is not without its disadvantages, however, and in this article alternative EPR dosimeters are explored. These include SO 3 - in irradiated K 2 CH 2 (SO 3 ) 2 and CO 2 - in irradiated sodium formate (NaHCO 2 ), both of which have some advantages over CH 3 CHCO 2 - in L-α-alanine. Using as a readout parameter the peak-to-peak excursion of the strongest line, these systems have a four-fold sensitivity advantage over alanine. The radicals SO 3 - and CO 2 - are, moreover, found in a wide variety of matrices, and it may be possible to find one in which they are even stronger. The need to discover a dosimeter material sensitive enough to function in the 'clinical' dose range (below 10 Gy) is emphasized. (author)

  2. New Generation of self-calibrated SS/EPR dosimeters: Alanine/EPR dosimeters

    International Nuclear Information System (INIS)

    Yordanov, N.D.; Gancheva, V.

    1999-01-01

    A new type of solid state/EPR dosimeters is described. Principally, it contains radiation sensitive diamagnetic material, some quantity of EPR active, but radiation insensitive, substance (for example Mn 2+ /MgO) and a binding material. In the present case alanine is used as a radiation sensitive substance. With this dosimeter, the EPR spectra of alanine and Mn 2+ are simultaneously recorded and the calibration graph represents the ratio of alanine versus Mn 2+ EPR signal intensity as a function of absorbed dose. In this way the reproducibility of the results is expected to be improved significantly including their intercomparison among different laboratories. Homogeneity of the prepared dosimeters and their behaviour (fading of EPR signals with time, influence of different meteorological conditions) show satisfactory reproducibility and stability with time. Because two different EPR active samples are recorded simultaneously, the influence of some instrument setting parameters (microwave power, modulation amplitude and modulation frequency) on the ratio I alanine /I Mn is also investigated. (author)

  3. Effects of Glutamine and Alanine Supplementation on Central Fatigue Markers in Rats Submitted to Resistance Training

    Directory of Open Access Journals (Sweden)

    Audrey Yule Coqueiro

    2018-01-01

    Full Text Available Recent evidence suggests that increased brain serotonin synthesis impairs performance in high-intensity intermittent exercise and specific amino acids may modulate this condition, delaying fatigue. This study investigated the effects of glutamine and alanine supplementation on central fatigue markers in rats submitted to resistance training (RT. Wistar rats were distributed in: sedentary (SED, trained (CON, trained and supplemented with alanine (ALA, glutamine and alanine in their free form (G + A, or as dipeptide (DIP. Trained groups underwent a ladder-climbing exercise for eight weeks, with progressive loads. In the last 21 days, supplementations were offered in water with a 4% concentration. Albeit without statistically significance difference, RT decreased liver glycogen, and enhanced the concentrations of plasma glucose, free fatty acids (FFA, hypothalamic serotonin, and ammonia in muscle and the liver. Amino acids affected fatigue parameters depending on the supplementation form. G + A prevented the muscle ammonia increase by RT, whereas ALA and DIP augmented ammonia and glycogen concentrations in muscle. DIP also increased liver ammonia. ALA and G + A reduced plasma FFA, whereas DIP increased this parameter, free tryptophan/total tryptophan ratio, hypothalamic serotonin, and the serotonin/dopamine ratio. The supplementations did not affect physical performance. In conclusion, glutamine and alanine may improve or impair central fatigue markers depending on their supplementation form.

  4. Alanine-EPR dosimetry in 10 MeV electron beam to optimize process parameters for food irradiation

    International Nuclear Information System (INIS)

    Sanyal, B.; Kumar, S.; Kumar, M.; Mittal, K.C.; Sharma, A.

    2011-01-01

    Absorbed dose in a food product is determined and controlled by several components of the LINAC irradiation facility as well as the product. Standardization of the parameters characterizing the facility components, process load and the irradiation conditions collectively termed as 'process parameters' are of paramount importance for successful dose delivery to the food products. In the present study alanine-EPR dosimetry system was employed to optimize the process parameters of 10 MeV electron beam of a LINAC facility for commercial irradiation of food. Three sets of experiments were carried out with different food commodities namely, mango, potato and rawa with the available product conveying system of different irradiation geometry like one sided or both sided mode of irradiation. Three dimensional dose distributions into the process load for low dose requiring food commodities (0.25 to 1 kGy) were measured in each experiment. The actual depth dose profile in food product and useful scan width of the electron beam were found out to be satisfactory for commercial radiation processing of food. Finally a scaled up experiment with commercial food product (packets of Rawa) exhibited adequate dose uniformity ratio of 3 proving the feasibility of the facility for large scale radiation processing of food commodities. (author)

  5. Sorption and Microbial Uptake of Alanine, Glucose and Acetate in Soil

    Science.gov (United States)

    Fischer, H.; Ingwersen, J.; Kuzyakov, Y.

    2009-04-01

    Low molecular weight organic substances (LMWOS), e. g. amino acids, sugars, and carboxylic acids, are C compounds that are most rapidly turned-over in the C cycle of soil. Despite of their importance it is still unknown how sorption to the soil matrix affects their turnover in soil solution. The goals of this study were (1) to describe the dynamics of the fluxes of LMWOS (10 µmol l-1) in various pools (dissolved, adsorbed, decomposed to CO2, incorporated into microbial biomass) and (2) to assess the LMWOS distribution in these pools in dependence of very wide range of concentration (0.01 to 1000 µmol l-1). Representatives of each LMWOS group (glucose for sugars, alanine for amino acids, Na-acetate for carboxylic acids) uniformly labeled with 14C were added to sterilized or non-sterilized soil and analyzed in dif-ferent compartments between 1 min and 5.6 hours after addition. LMWOS were almost completely taken up by microorganisms within the first 30 min. Microbial uptake was much faster than the physicochemical sorption (estimated in sterilized soil), which needed to reach quasi-equilibrium 60 min for alanine and about 400 min for glucose. Only sorption of acetate was instantaneous (>1 min). While for acetate the maximum sorption capacity was reached at 100 µmol l-1 no such maximum was found for glucose and alanine in the studied concentra-tion range. At the concentration of 100 µmol l-1, microbial decomposition after 4.5 h hours was higher for alanine (76.7±1.1%) than acetate (55.2±0.9%) and glucose (28.5±1.5%). On the contrary, incorporation into microbial biomass was higher for glucose (59.8±1.2%) than for acetate (23.4±5.9%) and alanine (5.2±2.8%). Within 10 to 500 µmol l-1 the pathways of the three LMWOS transformation changed: at 500 µmol l-1 alanine and acetate were less mineralized and more incorporated into microbial biomass than at 10 µmol l-1, while glucose incorporation decreased. Consequently, the concentrations of alanine, glucose, and

  6. Membrane proximal external region of gp41 from HIV-1 strains HXB2 and JRFL has different sensitivity to alanine mutation

    Science.gov (United States)

    Yi, Hyun Ah; Diaz-Rohrer, Barbara; Saminathan, Priyanka; Jacobs, Amy

    2015-01-01

    The transmembrane subunit (gp41) of the HIV envelope protein complex (Env) mediates the viral fusion step of HIV entry. The membrane-proximal external region (MPER), one of the functional domains of gp41, has been the focus of a great deal of research because it is a target for neutralizing antibodies. In this study, we examined 23 amino acid residues in MPER (660-683) in both a CXCR4 co-receptor utilizing strain (HXB2) and a CCR5 utilizing strain (JRFL) by alanine scanning mutagenesis. Despite the high degree of gp41 sequence conservation, the effects of alanine mutation in the MPER were different between the two strains. Most mutations in HXB2 had fusogenicity and protein expression levels not less than 50% of wild type in the case of cell-cell fusion. However, about thirty percent of the mutants in HXB2 showed a severe defect in fusogenicity in viral entry. Mutations in the MPER of strain JRFL had more dramatic effects than HXB2 in cell-cell fusion and viral entry. The fact that there are large differences in the effects of mutation between two strains suggests the potential for MPER interaction with non-conserved sequences such as the fusion peptide and/or other NHR domains as well as potential long-range structural effects on the conformational changes that occur with the Env complex during membrane fusion. PMID:25649507

  7. Self-Assembly, Supramolecular Organization, and Phase Behavior of L-Alanine Alkyl Esters (n = 9-18) and Characterization of Equimolar L-Alanine Lauryl Ester/Lauryl Sulfate Catanionic Complex.

    Science.gov (United States)

    Sivaramakrishna, D; Swamy, Musti J

    2015-09-08

    A homologous series of l-alanine alkyl ester hydrochlorides (AEs) bearing 9-18 C atoms in the alkyl chain have been synthesized and characterized with respect to self-assembly, supramolecular structure, and phase transitions. The CMCs of AEs bearing 11-18 C atoms were found to range between 0.1 and 10 mM. Differential scanning calorimetric (DSC) studies showed that the transition temperatures (Tt), enthalpies (ΔHt) and entropies (ΔSt) of AEs in the dry state exhibit odd-even alternation, with the odd-chain-length compounds having higher Tt values, but the even-chain-length homologues showing higher values of ΔHt and ΔSt. In DSC measurements on hydrated samples, carried out at pH 5.0 and pH 10.0 (where they exist in cationic and neutral forms, respectively), compounds with 13-18 C atoms in the alkyl chain showed sharp gel-to-liquid crystalline phase transitions, and odd-even alternation was not seen in the thermodynamic parameters. The molecular structure, packing properties, and intermolecular interactions of AEs with 9 and 10 C atoms in the alkyl chain were determined by single crystal X-ray diffraction, which showed that the alkyl chains are packed in a tilted interdigitated bilayer format. d-Spacings obtained from powder X-ray diffraction studies exhibited a linear dependence on the alkyl chain length, suggesting that the other AEs also adopt an interdigitated bilayer structure. Turbidimetric, fluorescence spectroscopic, and isothermal titration calorimetric (ITC) studies established that in aqueous dispersions l-alanine lauryl ester hydrochloride (ALE·HCl) and sodium dodecyl sulfate (SDS) form an equimolar complex. Transmission electron microscopic and DSC studies indicate that the complex exists as unilamellar liposomes, which exhibit a sharp phase transition at ∼39 °C. The aggregates were disrupted at high pH, suggesting that the catanionic complex would be useful to develop a base-labile drug delivery system. ITC studies indicated that ALE·HCl forms

  8. Mixed mode fracture of dental interfaces

    International Nuclear Information System (INIS)

    Rahbar, Nima; Yang, Yong; Soboyejo, Winston

    2008-01-01

    This paper presents the results of a combined experimental and computational study of mixed mode fracture in glass/cement and zirconia/cement interfaces that are relevant to dental restorations. The interfacial fracture is investigated using Brazil-nut specimens. The kinking in-and-out of the interface that occurs between glass/cement and zirconia/cement interfaces, is also shown to be consistent with predictions from a microstructure-based finite element model. The predictions later verified using focused ion beam and scanning electron microscopy images

  9. Alanine racemase is essential for the growth and interspecies competitiveness of Streptococcus mutans.

    Science.gov (United States)

    Wei, Yuan; Qiu, Wei; Zhou, Xue-Dong; Zheng, Xin; Zhang, Ke-Ke; Wang, Shi-Da; Li, Yu-Qing; Cheng, Lei; Li, Ji-Yao; Xu, Xin; Li, Ming-Yun

    2016-12-16

    D-alanine (D-Ala) is an essential amino acid that has a key role in bacterial cell wall synthesis. Alanine racemase (Alr) is a unique enzyme that interconverts L-alanine and D-alanine in most bacteria, making this enzyme a potential target for antimicrobial drug development. Streptococcus mutans is a major causative factor of dental caries. The factors involved in the survival, virulence and interspecies interactions of S. mutans could be exploited as potential targets for caries control. The current study aimed to investigate the physiological role of Alr in S. mutans. We constructed alr mutant strain of S. mutans and evaluated its phenotypic traits and interspecies competitiveness compared with the wild-type strain. We found that alr deletion was lethal to S. mutans. A minimal supplement of D-Ala (150 μg·mL -1 ) was required for the optimal growth of the alr mutant. The depletion of D-alanine in the growth medium resulted in cell wall perforation and cell lysis in the alr mutant strain. We also determined the compromised competitiveness of the alr mutant strain relative to the wild-type S. mutans against other oral streptococci (S. sanguinis or S. gordonii), demonstrated using either conditioned medium assays or dual-species fluorescent in situ hybridization analysis. Given the importance and necessity of alr to the growth and competitiveness of S. mutans, Alr may represent a promising target to modulate the cariogenicity of oral biofilms and to benefit the management of dental caries.

  10. Persistent GABAA/C responses to gabazine, taurine and beta-alanine in rat hypoglossal motoneurons.

    Science.gov (United States)

    Chesnoy-Marchais, D

    2016-08-25

    In hypoglossal motoneurons, a sustained anionic current, sensitive to a blocker of ρ-containing GABA receptors, (1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid (TPMPA) and insensitive to bicuculline, was previously shown to be activated by gabazine. In order to better characterize the receptors involved, the sensitivity of this atypical response to pentobarbital (30μM), allopregnanolone (0.3μM) and midazolam (0.5μM) was first investigated. Pentobarbital potentiated the response, whereas the steroid and the benzodiazepine were ineffective. The results indicate the involvement of hybrid heteromeric receptors, including at least a GABA receptor ρ subunit and a γ subunit, accounting for the pentobarbital-sensitivity. The effects of the endogenous β amino acids, taurine and β-alanine, which are released under various pathological conditions and show neuroprotective properties, were then studied. In the presence of the glycine receptor blocker strychnine (1μM), both taurine (0.3-1mM) and β-alanine (0.3mM) activated sustained anionic currents, which were partly blocked by TPMPA (100μM). Thus, both β amino acids activated ρ-containing GABA receptors in hypoglossal motoneurons. Bicuculline (20μM) reduced responses to taurine and β-alanine, but small sustained responses persisted in the presence of both strychnine and bicuculline. Responses to β-alanine were slightly increased by allopregnanolone, indicating a contribution of the bicuculline- and neurosteroid-sensitive GABAA receptors underlying tonic inhibition in these motoneurons. Since sustained activation of anionic channels inhibits most mature principal neurons, the ρ-containing GABA receptors permanently activated by taurine and β-alanine might contribute to some of their neuroprotective properties under damaging overexcitatory situations. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

  11. K-band EPR dosimetry: small-field beam profile determination with miniature alanine dosimeter

    International Nuclear Information System (INIS)

    Chen, Felipe; Graeff, Carlos F.O.; Baffa, Oswaldo

    2005-01-01

    The use of small-size alanine dosimeters presents a challenge because the signal intensity is less than the spectrometer sensitivity. K-band (24 GHz) EPR spectrometer seems to be a good compromise between size and sensitivity of the sample. Miniature alanine pellets were evaluated for small-field radiation dosimetry. Dosimeters of DL-alanine/PVC with dimensions of 1.5 mm diameter and 2.5 mm length with 5 mg mass were developed. These dosimeters were irradiated with 10 MV X-rays in the dose range 0.05-60 Gy and the first harmonic (1 h) spectra were recorded. Microwave power, frequency and amplitude of modulation were optimized to obtain the best signal-to-noise ratio (S/N). For beam profile determination, a group of 25 dosimeters were placed in an acrylic device with dimensions of (7.5x2.5x1) cm 3 and irradiated with a (3x3) cm 2 10 MV X-rays beam field size. The dose at the central region of the beam was 20 Gy at a depth of 2.2 cm (build up for acrylic). The acrylic device was oriented perpendicular to the beam axis and to the gantry rotation axis. For the purposes of comparison of the spatial resolution, the beam profile was also determined with a radiographic film and 2 mm aperture optical densitometer; in this case the dose was 1 cGy. The results showed a similar spatial resolution for both types of dosimeters. The dispersion in dose reading was larger for alanine in comparison with the film, but alanine dosimeters can be read faster and more directly than film over a wide dose range

  12. The metabolism of histamine in the Drosophila optic lobe involves an ommatidial pathway: β-alanine recycles through the retina

    Science.gov (United States)

    Borycz, Janusz; Borycz, Jolanta A.; Edwards, Tara N.; Boulianne, Gabrielle L.; Meinertzhagen, Ian A.

    2012-01-01

    SUMMARY Flies recycle the photoreceptor neurotransmitter histamine by conjugating it to β-alanine to form β-alanyl-histamine (carcinine). The conjugation is regulated by Ebony, while Tan hydrolyses carcinine, releasing histamine and β-alanine. In Drosophila, β-alanine synthesis occurs either from uracil or from the decarboxylation of aspartate but detailed roles for the enzymes responsible remain unclear. Immunohistochemically detected β-alanine is present throughout the fly’s entire brain, and is enhanced in the retina especially in the pseudocone, pigment and photoreceptor cells of the ommatidia. HPLC determinations reveal 10.7 ng of β-alanine in the wild-type head, roughly five times more than histamine. When wild-type flies drink uracil their head β-alanine increases more than after drinking l-aspartic acid, indicating the effectiveness of the uracil pathway. Mutants of black, which lack aspartate decarboxylase, cannot synthesize β-alanine from l-aspartate but can still synthesize it efficiently from uracil. Our findings demonstrate a novel function for pigment cells, which not only screen ommatidia from stray light but also store and transport β-alanine and carcinine. This role is consistent with a β-alanine-dependent histamine recycling pathway occurring not only in the photoreceptor terminals in the lamina neuropile, where carcinine occurs in marginal glia, but vertically via a long pathway that involves the retina. The lamina’s marginal glia are also a hub involved in the storage and/or disposal of carcinine and β-alanine. PMID:22442379

  13. Synthesis, characterization and photo behavior of new poly(amide-imide/montmorillonite nanocomposite containing N,N'-pyrromellitoyl-bis-L-alanine

    Directory of Open Access Journals (Sweden)

    M. Hajibeygi

    2013-09-01

    Full Text Available Two new samples of poly(amide-imide-nanocomposites were synthesized by insertion nano silicate particles in poly(amide-imide (PAI chains using a convenient solution intercalation technique. PAI as a source of polymer matrix was synthesized by the direct polycondensation reaction of N,N'-pyrromelitoyl-bis-L-alanine with 4,4'-diamino diphenyl ether in the presence of triphenyl phosphite (TPP, CaCl2, pyridine and N-methyl-2-pyrrolidone (NMP. Morphology and structure of the resulting PAI-nanocomposite films with 5 and 10% silicate particles were characterized by FTIR spectroscopy, X-ray diffraction (XRD and scanning electron microscopy (SEM. The effect of clay dispersion and the interaction between clay and polymeric chains on the properties of nanocomposites films were investigated by using UV-Vis spectroscopy, thermogravimetric analysis (TGA and water uptake measurements.DOI: http://dx.doi.org/10.4314/bcse.v27i3.15

  14. Lung PET scan

    Science.gov (United States)

    ... Chest PET scan; Lung positron emission tomography; PET - chest; PET - lung; PET - tumor imaging; ... Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging . 6th ed. Philadelphia, ...

  15. Scanning of bone metastases

    International Nuclear Information System (INIS)

    Robillard, J.

    1977-01-01

    The Centers against cancer of Caen, Angers, Montpellier, Strasbourg and 'the Curie Foundation' have confronted their experience in detection of bone metastases by total body scanning. From the investigation by this procedure, of 1,467 patients with cancer, it results: the confrontation between radio and scanning shows a rate of false positive and false negative identical to the literature ones; the countage scanning allows to reduce the number of false positive; scanning allows to direct bone biopsy and to improve efficiency of histological examination [fr

  16. The alanine detector in BNCT dosimetry: dose response in thermal and epithermal neutron fields.

    Science.gov (United States)

    Schmitz, T; Bassler, N; Blaickner, M; Ziegner, M; Hsiao, M C; Liu, Y H; Koivunoro, H; Auterinen, I; Serén, T; Kotiluoto, P; Palmans, H; Sharpe, P; Langguth, P; Hampel, G

    2015-01-01

    The response of alanine solid state dosimeters to ionizing radiation strongly depends on particle type and energy. Due to nuclear interactions, neutron fields usually also consist of secondary particles such as photons and protons of diverse energies. Various experiments have been carried out in three different neutron beams to explore the alanine dose response behavior and to validate model predictions. Additionally, application in medical neutron fields for boron neutron capture therapy is discussed. Alanine detectors have been irradiated in the thermal neutron field of the research reactor TRIGA Mainz, Germany, in five experimental conditions, generating different secondary particle spectra. Further irradiations have been made in the epithermal neutron beams at the research reactors FiR 1 in Helsinki, Finland, and Tsing Hua open pool reactor in HsinChu, Taiwan ROC. Readout has been performed with electron spin resonance spectrometry with reference to an absorbed dose standard in a (60)Co gamma ray beam. Absorbed doses and dose components have been calculated using the Monte Carlo codes fluka and mcnp. The relative effectiveness (RE), linking absorbed dose and detector response, has been calculated using the Hansen & Olsen alanine response model. The measured dose response of the alanine detector in the different experiments has been evaluated and compared to model predictions. Therefore, a relative effectiveness has been calculated for each dose component, accounting for its dependence on particle type and energy. Agreement within 5% between model and measurement has been achieved for most irradiated detectors. Significant differences have been observed in response behavior between thermal and epithermal neutron fields, especially regarding dose composition and depth dose curves. The calculated dose components could be verified with the experimental results in the different primary and secondary particle fields. The alanine detector can be used without

  17. β-N-Methylamino-L-alanine (BMAA) perturbs alanine, aspartate and glutamate metabolism pathways in human neuroblastoma cells as determined by metabolic profiling.

    Science.gov (United States)

    Engskog, Mikael K R; Ersson, Lisa; Haglöf, Jakob; Arvidsson, Torbjörn; Pettersson, Curt; Brittebo, Eva

    2017-05-01

    β-Methylamino-L-alanine (BMAA) is a non-proteinogenic amino acid that induces long-term cognitive deficits, as well as an increased neurodegeneration and intracellular fibril formation in the hippocampus of adult rodents following short-time neonatal exposure and in vervet monkey brain following long-term exposure. It has also been proposed to be involved in the etiology of neurodegenerative disease in humans. The aim of this study was to identify metabolic effects not related to excitotoxicity or oxidative stress in human neuroblastoma SH-SY5Y cells. The effects of BMAA (50, 250, 1000 µM) for 24 h on cells differentiated with retinoic acid were studied. Samples were analyzed using LC-MS and NMR spectroscopy to detect altered intracellular polar metabolites. The analysis performed, followed by multivariate pattern recognition techniques, revealed significant perturbations in protein biosynthesis, amino acid metabolism pathways and citrate cycle. Of specific interest were the BMAA-induced alterations in alanine, aspartate and glutamate metabolism and as well as alterations in various neurotransmitters/neuromodulators such as GABA and taurine. The results indicate that BMAA can interfere with metabolic pathways involved in neurotransmission in human neuroblastoma cells.

  18. Purification, characterization and gene cloning of thermostable O-acetyl-L-serine sulfhydrylase forming β-cyano-L-alanine

    International Nuclear Information System (INIS)

    Omura, Hironori; Yoshida, Toyokazu; Nagasawa, Toru; Kobayashi, Michihiko; Shimizu, Sakayu

    2003-01-01

    A thermophilic and cyanide ion-tolerant bacterium, Bacillus stearothermophilus CN3 isolated from a hot spring in Japan, was found to produce thermostable β-cyano-L-alanine synthase. The enzyme catalyzes the synthesis of β-cyano-L-alanine from O-acetyl-L-serine and cyanide ions. The purified enzyme has a molecular mass of approximately 70 kDa and consists of two identical sub-units. It was stable in the pH range of 6.0 to 10.0 and up to 70degC. The enzyme also catalyzes the synthesis of various β-substituted-L-alanine derivatives from O-acetyl-L-serine and nucleophilic reagents. The gene encoding the β-cyano-L-alanine synthase was isolated from B. stearothermophilus CN3. Sequence homology analysis revealed that the β-cyano-L-alanine synthase of the bacterium is O-acetyl-L-serine sulfhydrylase. A recombinant plasmid, constructed by ligation of the cloned gene and an expression vector, pKK223-3, was introduced into E. coli JM109. The transformed E. coli cells overexpressed β-cyano-L-alanine synthase. Heat stable β-cyano-L-alanine synthase can be applied to the synthesis of [4- 11 C]L-2,4-diaminobutyric acid as a tracer for positron emission tomography. (author)

  19. Thermochemistry of the solution of β-alanine in (H2O + alcohol) mixtures at 298.15 K

    International Nuclear Information System (INIS)

    Smirnov, Valeriy I.; Badelin, Valentin G.

    2013-01-01

    Highlights: • Enthalpies of β-alanine dissolution have been measured in aqueous solution of MeOH, EtOH, 1-PrOH and 2-PrOH. • Measured data were reported as functions of composition of water + alcohol mixtures. • Enthalpy coefficients of pairwise interactions have been analyzed in terms of McMillan–Mayer theory. - Abstract: The enthalpies of the solution of β-alanine in H 2 O + (methanol, ethanol, 1-propanol and 2-propanol) mixtures with alcohol content up to 0.4 mol fractions, have been determined calorimetrically at T = 298.15 K. The standard enthalpies of the solution and transfer of β-alanine from water to aqueous alcohol have been calculated. The effect of structure properties of a mixed solvent on specified enthalpy characteristics of β-alanine is discussed. The enthalpy coefficients of pairwise interactions between β-alanine and alcohol molecules have been computed. It has been found that these coefficients become increasingly positive in methanol, ethanol, 1-propanol, and 2-propanol sequence. A comparative analysis of thermodynamic characteristics of dissolution of β-alanine and D,L-α-alanine in the mixtures studied has been made

  20. Calculations of the relative effectiveness of alanine for neutrons with energies up to 17.1 MeV

    International Nuclear Information System (INIS)

    Gerstenberg, H.M.; Coyne, J.J.

    1990-01-01

    The relative effectiveness (RE) of alanine has been calculated for neutrons using the RE of alanine for charged particles. The neutrons interact with one or more of the elements (hydrogen, carbon, nitrogen and oxygen) that compose the alanine. These interactions produce spectra of secondary charged particles consisting of ions of H, D, He, Be, B, C, N and O. From a combination of the calculated secondary charged particle spectra generated by the slowing down neutrons, and the calculated RE of the ions produced, a RE for the neutrons can be obtained. In addition, lineal energy spectra were determined for neutrons with energies up to 17.1 MeV interacting with alanine. An analytical code was used to calculate these spectra for a 1 μm diameter alanine cell surrounded by an alanine medium. For comparison, similar calculations were made for muscle tissue. Finally, the calculated differential RE was folded with dose distributions to obtain RE-weighted distributions for alanine. (author)

  1. Purification, characterization and gene cloning of thermostable O-acetyl-L-serine sulfhydrylase forming {beta}-cyano-L-alanine

    Energy Technology Data Exchange (ETDEWEB)

    Omura, Hironori; Yoshida, Toyokazu; Nagasawa, Toru [Gifu Univ. (Japan). Dept. of Biomolecular Science; Kuroda, Masako [Ikeda Food Research Co., Ltd., Fukuyama, Hiroshima (Japan); Kobayashi, Michihiko; Shimizu, Sakayu [Kyoto Univ. (Japan). Agricultural Sciences

    2003-10-01

    A thermophilic and cyanide ion-tolerant bacterium, Bacillus stearothermophilus CN3 isolated from a hot spring in Japan, was found to produce thermostable {beta}-cyano-L-alanine synthase. The enzyme catalyzes the synthesis of {beta}-cyano-L-alanine from O-acetyl-L-serine and cyanide ions. The purified enzyme has a molecular mass of approximately 70 kDa and consists of two identical sub-units. It was stable in the pH range of 6.0 to 10.0 and up to 70degC. The enzyme also catalyzes the synthesis of various {beta}-substituted-L-alanine derivatives from O-acetyl-L-serine and nucleophilic reagents. The gene encoding the {beta}-cyano-L-alanine synthase was isolated from B. stearothermophilus CN3. Sequence homology analysis revealed that the {beta}-cyano-L-alanine synthase of the bacterium is O-acetyl-L-serine sulfhydrylase. A recombinant plasmid, constructed by ligation of the cloned gene and an expression vector, pKK223-3, was introduced into E. coli JM109. The transformed E. coli cells overexpressed {beta}-cyano-L-alanine synthase. Heat stable {beta}-cyano-L-alanine synthase can be applied to the synthesis of [4-{sup 11}C]L-2,4-diaminobutyric acid as a tracer for positron emission tomography. (author)

  2. Model PET Scan Activity

    Science.gov (United States)

    Strunk, Amber; Gazdovich, Jennifer; Redouté, Oriane; Reverte, Juan Manuel; Shelley, Samantha; Todorova, Vesela

    2018-05-01

    This paper provides a brief introduction to antimatter and how it, along with other modern physics topics, is utilized in positron emission tomography (PET) scans. It further describes a hands-on activity for students to help them gain an understanding of how PET scans assist in detecting cancer. Modern physics topics provide an exciting way to introduce students to current applications of physics.

  3. Scanning laser Doppler vibrometry

    DEFF Research Database (Denmark)

    Brøns, Marie; Thomsen, Jon Juel

    With a Scanning Laser Doppler Vibrometer (SLDV) a vibrating surface is automatically scanned over predefined grid points, and data processed for displaying vibration properties like mode shapes, natural frequencies, damping ratios, and operational deflection shapes. Our SLDV – a PSV-500H from...

  4. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available Toggle navigation Test/Treatment Patient Type Screening/Wellness Disease/Condition Safety En Español More Info Images/Videos About Us News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake Thyroid scan and uptake uses ...

  5. Volume dose ratios relevant for alanine dosimetry in small, 6 MV photon beams

    DEFF Research Database (Denmark)

    Cronholm, Rickard O.; Andersen, Claus Erik; Behrens, Claus F.

    2012-01-01

    therapy). To this end, we here present the results of a Monte Carlo simulation study with DOSRZnrc that investigated the influence of field and detector size for small 6 MV photon beams. The study focusses on doses averaged over the volume of the detector rather than point doses.The ratio of volume...... averaged doses to water (D¯W) and alanine (D¯det) was found to be approximately 1.025 for most situations studied, and a constant ratio is likely to be representative for many applications in radiation therapy. However, D¯W/D¯det was found to be as low as 0.9908 ± 0.0037 in situations where one might...... expect significant deviations from charged particle equilibrium (i.e. at shallow depths and when the field size was smaller than the range of the secondary electrons). These effects therefore need consideration when finite-size alanine dosimeters are used under such conditions....

  6. Crystallization and preliminary X-ray diffraction analysis of alanine racemase from Pseudomonas putida YZ-26

    International Nuclear Information System (INIS)

    Liu, Junlin; Feng, Lei; Shi, Yawei; Feng, Wei

    2012-01-01

    A recombinant alanine racemase from the Pseudomonas putida YZ-26, has been crystallized by the sitting-drop vapor-diffusion method and X-ray diffraction data were collected to 2.4 Å. A recombinant form of alanine racemase (Alr) from Pseudomonas putida YZ-26 has been crystallized by the sitting-drop vapour diffusion method. X-ray diffraction data were collected to 2.4 Å resolution. The crystals belong to the space group C222 1 , with unit-cell parameters a = 118.08, b = 141.86, c = 113.83 Å, and contain an Alr dimer in the asymmetric unit. The Matthews coefficient and the solvent content were calculated to be 2.8 Å 3 Da −1 and approximately 50%, respectively

  7. Development of physical and numerical techniques of Alanine/EPR dosimetry in radiotherapy

    International Nuclear Information System (INIS)

    Castro, F.; Ponte, F.; Pereira, L.

    2006-01-01

    In this work, a set of 50 alanine dosimeters has been used in a radiotherapy context, simulating a two-dimensional treatment in a non-overlapping dosimeter configuration. The dose is reconstructed from physical and numerical simulation of the electron paramagnetic resonance signal, calculating the spin density. Thus, it can be used to better adjust the error in the calibration curve to give a final accuracy of <0.03 Gy. A complete set of experimental test parameters have been used with a standard dosimeter in order to obtain the best analysis configuration. These results indicate that for a conventional treatment of some hundreds of mGy, this method can be useful with a correct signal validation. A numerical test and fitting software has been developed. The general use of alanine/electron paramagnetic resonance dosimetry in radiotherapy context is discussed. (authors)

  8. Development of DL-alanine systems for gamma radiation and electron dosimetry

    International Nuclear Information System (INIS)

    Costa, Zelia Maria da

    1994-01-01

    Two different dosimetric systems using DL-Alanine samples were employed to determine the absorbed dose from 60 Co gamma-rays source and electrons emitted from an accelerator. The first dosimetric system is based on the relationship between free radicals produced and the absorbed dose using the electron spin resonance (ESR) technique. Details on the sample preparation, the spectrometer parameter setting, the analysis of the ESR signal to dose, the influence of dose rate and the radiation type dependence are described. The second dosimetric system is based on the determination by absorbance spectrophotometry of the complex produced, which are formed when the irradiated alanine is dissolved in a solution containing ferrous ammonium sulphate xylenol in 0,05 N H 2 SO 4 . Different concentrations for each reagents has been analyzed in the preparation of this solution as well as the influence caused by radiation type and dose rate in the absorbance. (author)

  9. Utilization of ALANPOL dosemeter composed by alanine and polyethylene for determination of doses in industrial effluents

    International Nuclear Information System (INIS)

    Rela, Carolina S.; Sampa, Maria Helena de O.; Napolitano, Celia M.; Pontuschka, Walter M.

    2005-01-01

    A study of traceability and accuracy was performed with the dosimetry system ALANPOL developed by IVHTJ/ Poland that uses alanine as a dosimeter and EPR as the read out system. The dosimeter ALANPOL is a polymer compound that aggregates alanine. The dosimeter has the outside diameter 3 mm, and the length of 25,4 mm (1 inch). In order to use this dosimeter for monitoring the existing real time calorimetry dosimeter system set up in a electron beam waste treatment plant. Electron beam and gamma irradiation experiments with ALANPOL was carried out under demineralized water and industrial effluent. The result show that in the dose range of 1-40 kGy the ALANPOL dosimeter system is suitable underwater monitoring for absorbed dose and can be applied for the evaluation of the on line calorimetry dosimeter system. (author)

  10. Braked rotation of CH3 group in L-alanine monocrystals: temperature transformation of EPR spectrum

    International Nuclear Information System (INIS)

    Lemanov, V.V.; Sochava, L.S.

    2003-01-01

    EPR spectra temperature transformation of the irradiated alanine crystals is used for studying rotation of CH 3 methyl group in L-alamine monocrystals. 60 Co (2 x 10 4 Gy dose) was applied as a γ-radiation source. The simple method of experimental data processing which is reduced to obtaining the resonance lines width dependence on the temperature is used for the quantitative analysis of the spectrum temperature transformation. Temperature dependence of the CH 3 group rotation frequency is identified on the basis of these data. Activation energy U = 0.18 eV and pre-exponential multiplier ω 0 = 10 13 s -1 are determined from the EPR spectra temperature transformation which are in good agreement with values obtained earlier from the measurements of the proton spin-lattice relaxation in alanine polycrystal samples [ru

  11. A reference dosimetric system for dose interval of radiotherapy based on alanine/RPE

    International Nuclear Information System (INIS)

    Rodrigues Junior, Orlando; Galante, Ocimar L.; Campos, Leticia L.

    2001-01-01

    This work describes the development of a reference dosimetric system based on alanine/EPR for radiotherapy dose levels. Currently the IPEN is concluding a similar system for the dose range used for irradiation of products, 10-10 5 Gy. The objective of this work is to present the efforts towards to improve the measure accuracy for doses in the range between 1-10 Gy. This system could be used as reference by radiotherapy services, as much in the quality control of the equipment, as for routine accompaniment of more complex handling where the total doses can reach some grays. The system uses alanine as detector and electronic paramagnetic resonance - EPR as measure technique. To reach accuracy better than 5% mathematical studies on the best optimization of the EPR spectrometer parameters and methods for the handling of the EPR sign are discussed. (author)

  12. Orientation of crystals in alanine dosimeter assessed by DRS, as seen in EPR spectra evaluation

    International Nuclear Information System (INIS)

    Grazyna Przybytniak; Zagorski, Z.P.

    1996-01-01

    The alanine dosimeter made for evaluation by diffuse light reflection spectrophotometry (ALA/DRS) does not show the effect of orientation of crystals. Supposed deviation from random orientation has been investigated by EPR spectroscopy. EPR investigation shows that in spite of the very fine size of L-alanine crystals, they are oriented in thin layers of the polyethylene matrix. Specially prepared films with deliberately well oriented crystals have confirmed this observation. Our ALA/DRS dosimeter can be evaluated by the EPR method for the concentration of free radicals, providing that the dominating crystal orientation in the dosimetric film is indicated on it as an arrow, and the sample is inserted into the magnetic cavity always in the same orientation as has been done during the calibration operation. (author). 6 refs., 2 figs

  13. Radiation-induced reactions in D, L-α-alanine adsorbed in solid surfaces

    International Nuclear Information System (INIS)

    Aguilar, E; Negrón-Mendoza, A.; Camargo, C.

    2013-01-01

    The aim of this work is to study the behavior under irradiation of D, L and D-L α-alanine adsorbed in solid surfaces, as possible phase in the chemical evolution that may have occurred on the primitive Earth or in extraterrestrial environments and to evaluate the contribution of solids (a clay mineral) as shields for the adsorbed amino acids against a external energy source. The results show that α-alanine is adsorbed in the surfaces as function of pH and its yield of decomposition in mineral suspension is lower than the system without the solid surface. These results show the importance of nuclear techniques in these types of studies. (author)

  14. Transverse section scanning mechanism

    International Nuclear Information System (INIS)

    Doherty, E.J.

    1978-01-01

    Apparatus is described for scanning a transverse, radionuclide scan-field using an array of focussed collimators. The collimators are movable tangentially on rails, driven by a single motor via a coupled screw. The collimators are also movable in a radial direction on rails driven by a step motor via coupled screws and bevel gears. Adjacent bevel gears rotate in opposite directions so adjacent collimators move in radially opposite directions. In use, the focal point of each collimator scans at least half of the scan-field, e.g. a human head located in the central aperture, and the electrical outputs of detectors associated with each collimator are used to determine the distribution of radioactive emission intensity at a number of points in the scan-field. (author)

  15. LIDAR COMBINED SCANNING UNIT

    Directory of Open Access Journals (Sweden)

    V. V. Elizarov

    2016-11-01

    Full Text Available Subject of Research. The results of lidar combined scanning unit development for locating leaks of hydrocarbons are presented The unit enables to perform high-speed scanning of the investigated space in wide and narrow angle fields. Method. Scanning in a wide angular field is produced by one-line scanning path by means of the movable aluminum mirror with a frequency of 20Hz and amplitude of 20 degrees of swing. Narrowband scanning is performed along a spiral path by the deflector. The deflection of the beam is done by rotation of the optical wedges forming part of the deflector at an angle of ±50. The control function of the scanning node is performed by a specialized software product written in C# programming language. Main Results. This scanning unit allows scanning the investigated area at a distance of 50-100 m with spatial resolution at the level of 3 cm. The positioning accuracy of the laser beam in space is 15'. The developed scanning unit gives the possibility to browse the entire investigated area for the time not more than 1 ms at a rotation frequency of each wedge from 50 to 200 Hz. The problem of unambiguous definition of the beam geographical coordinates in space is solved at the software level according to the rotation angles of the mirrors and optical wedges. Lidar system coordinates are determined by means of GPS. Practical Relevance. Development results open the possibility for increasing the spatial resolution of scanning systems of a wide range of lidars and can provide high positioning accuracy of the laser beam in space.

  16. Photochemical redox reactions of copper(II)-alanine complexes in aqueous solutions.

    Science.gov (United States)

    Lin, Chen-Jui; Hsu, Chao-Sheng; Wang, Po-Yen; Lin, Yi-Liang; Lo, Yu-Shiu; Wu, Chien-Hou

    2014-05-19

    The photochemical redox reactions of Cu(II)/alanine complexes have been studied in deaerated solutions over an extensive range of pH, Cu(II) concentration, and alanine concentration. Under irradiation, the ligand-to-metal charge transfer results in the reduction of Cu(II) to Cu(I) and the concomitant oxidation of alanine, which produces ammonia and acetaldehyde. Molar absorptivities and quantum yields of photoproducts for Cu(II)/alanine complexes at 313 nm are characterized mainly with the equilibrium Cu(II) speciation where the presence of simultaneously existing Cu(II) species is taken into account. By applying regression analysis, individual Cu(I) quantum yields are determined to be 0.094 ± 0.014 for the 1:1 complex (CuL) and 0.064 ± 0.012 for the 1:2 complex (CuL2). Individual quantum yields of ammonia are 0.055 ± 0.007 for CuL and 0.036 ± 0.005 for CuL2. Individual quantum yields of acetaldehyde are 0.030 ± 0.007 for CuL and 0.024 ± 0.007 for CuL2. CuL always has larger quantum yields than CuL2, which can be attributed to the Cu(II) stabilizing effect of the second ligand. For both CuL and CuL2, the individual quantum yields of Cu(I), ammonia, and acetaldehyde are in the ratio of 1.8:1:0.7. A reaction mechanism for the formation of the observed photoproducts is proposed.

  17. A COMPARATIVE STUDY ON THE ACTIVITY OF ALANIN-AMINOTRANSFERASE IN HYPOPHTHALMICHTHYS MOLITRIX AND ARISTICHTHYS NOBILIS

    Directory of Open Access Journals (Sweden)

    Gabriela Vasile

    2006-08-01

    Full Text Available The present paper represents a comparative study on the activity of one aminotransferase - alaninaminotransferase, in the digestive tube of Hypophthalmichthys molitrix (silver carp and Aristichthys nobilis (bighead carp. The enzymatic activity has been determined colorimetrically, with 2, 4 - dinitrophenyl hydrazine, the results obtained being expressed as UE / g / min. It was observed that, comparatively with the alanin-aminotransferase activity recorded in silver carp, in the case of bighead carp, the values recorded are much lower.

  18. β-alanine supplementation improves isometric endurance of the knee extensor muscles

    Directory of Open Access Journals (Sweden)

    Sale Craig

    2012-06-01

    Full Text Available Abstract Background We examined the effect of four weeks of β-alanine supplementation on isometric endurance of the knee extensors at 45% maximal voluntary isometric contraction (MVIC. Methods Thirteen males (age 23 ± 6 y; height 1.80 ± 0.05 m; body mass 81.0 ± 10.5 kg, matched for pre-supplementation isometric endurance, were allocated to either a placebo (n = 6 or β-alanine (n = 7; 6.4 g·d-1 over 4 weeks supplementation group. Participants completed an isometric knee extension test (IKET to fatigue, at an intensity of 45% MVIC, before and after supplementation. In addition, two habituation tests were completed in the week prior to the pre-supplementation test and a further practice test was completed in the week prior to the post-supplementation test. MVIC force, IKET hold-time, and impulse generated were recorded. Results IKET hold-time increased by 9.7 ± 9.4 s (13.2% and impulse by 3.7 ± 1.3 kN·s-1 (13.9% following β-alanine supplementation. These changes were significantly greater than those in the placebo group (IKET: t(11 = 2.9, p ≤0.05; impulse: t(11 = 3.1, p ≤ 0.05. There were no significant changes in MVIC force in either group. Conclusion Four weeks of β-alanine supplementation at 6.4 g·d-1 improved endurance capacity of the knee extensors at 45% MVIC, which most likely results from improved pH regulation within the muscle cell as a result of elevated muscle carnosine levels.

  19. Adsorption of alanine with heteroatom substituted fullerene for solar cell application: A DFT study.

    Science.gov (United States)

    Dheivamalar, S; Sugi, L; Ravichandran, K; Sriram, S

    2018-05-14

    C 20 is the most important fullerene cage and alanine is the simplest representation of a backbone unit of the protein. The absorption feasibility of alanine molecule in the Si-doped C 20 and B-doped C 20 fullerenes has been studied based on calculated electronic properties of fullerenes using density functional theory (DFT). In this work, we explore the ability of Si-doped C 20 , B-doped C 20 fullerene to interact with alanine at the DFT-B3LYP/6-31G, RHF level of theory. We find that noticeable structural change takes place in C 20 when one of its carbon is substituted with Si or B. The molecular geometry, electronic properties and vibrational analysis have also been performed on the title compounds. The NMR study reveals the aromaticity of the pure and doped fullerene compounds. Stability of the doped fullerene - alanine compound arises from hyper conjugative interactions. It leads to one of the major property of bioactivity, charge transfer and delocalization of charge and this properties has been analyzed using Natural Bond Orbital (NBO) analysis. The energy gap of the doped fullerene reveals that there is a decrease in the size of energy gap significantly, making them more reactive as compared to C 20 fullerene. Theoretical studies of the electronic spectra by using time - dependent density functional theory (TD-DFT) method were helpful to interpret the observed electronic transition state. We aim to optimize the performance of the solar cells by altering the frontier orbital energy gaps. Considering all studied properties, it may be inferred that the applicability of C 20 fullerene as the non-linear optical (NLO) material and its NLO property would increase on doping fullerene with Si and B atom. Specifically C 19 Si would be better among them. Copyright © 2018. Published by Elsevier B.V.

  20. and alanine (EC. 2.6.1.2) transaminases, and alkaline phosphatase

    African Journals Online (AJOL)

    The activities of aspartate (E.C. 2.6.1.1) and alanine (E.C. 2.6.1.2) transaminases (AST and ALT, respectively), and alkaline phosphatase (ALP) (E.C. 3.1.3.1) were determined in erythrocytes obtained from 20 HbAA, 15 HbAS and 12 HbSS human subjects. The results showed that the three enzymes had different levels of ...

  1. Uracil and beta-alanine degradation in Saccharomyces Kluyveri - discovery of a novel catabolic pathway

    DEFF Research Database (Denmark)

    Andersen, Gorm

    2006-01-01

    ’en i gær og de genetiske forudsætninger for uracil og beta-alanine (BAL) katabolisme i S. kluyveri undersøgt. Evnen til at bruge uracil, dihydrouracil (DHU), beta-ureidopropionate (BUP) og BAL som nitrogenkilde blev studeret i 38 gær arter. Disse var udvalgt, så de dækkede “Saccharomyces komplekset...

  2. Diverse taxa of cyanobacteria produce β-N-methylamino-l-alanine, a neurotoxic amino acid

    OpenAIRE

    Cox, Paul Alan; Banack, Sandra Anne; Murch, Susan J.; Rasmussen, Ulla; Tien, Georgia; Bidigare, Robert Richard; Metcalf, James S.; Morrison, Louise F.; Codd, Geoffrey A.; Bergman, Birgitta

    2005-01-01

    Cyanobacteria can generate molecules hazardous to human health, but production of the known cyanotoxins is taxonomically sporadic. For example, members of a few genera produce hepatotoxic microcystins, whereas production of hepatotoxic nodularins appears to be limited to a single genus. Production of known neurotoxins has also been considered phylogenetically unpredictable. We report here that a single neurotoxin, β-N-methylamino-l-alanine, may be produced by all known groups of cyanobacteria...

  3. Sequential enzymatic synthesis and separation of 13N-L-glutamic acid and 13N-L-alanine

    International Nuclear Information System (INIS)

    Cohen, M.B.; Spolter, L.; MacDonald, M.; Chang, C.C.; Takahashi, J.

    1975-01-01

    The sequential enzymatic synthesis and separation of 13 N-L-glutamic acid and 13 N-L-alanine are described. Basically, that involves the synthesis of 13 N-L-glutamic acid by one enzyme, the transamination of the labeled glutamic acid to form 13 N-L-alanine by a second enzyme, and the separation of the two amino acids by rapid column chromatography. The 13 N-L-alanine was evaluated in animals by imaging and tissue distribution studies and showed good potential as a pancreatic imaging agent

  4. Determination of isodose curves in Radiotherapy using an Alanine/ESR dosemeter

    International Nuclear Information System (INIS)

    Chen, F.; Baffa, O.; Graeff, C.F.O.

    1998-01-01

    It was studied the possible use of an Alanine/ESR dosemeter in the isodose curves mapping in normal treatments of Radiotherapy. It was manufactured a lot of 150 dosemeters with base in a mixture of D-L Alanine dust (80 %) and paraffin (20 %). Each dosemeter has 4.7 mm diameter and 12 mm length. A group of 100 dosemeters of the lot were arranged inside 50 holes of the slice 25 of the phantom Rando Man. The phantom irradiation was realized in two opposed projections (AP and PA) in Co-60 equipment. A group of 15 dosemeters was take of the same lot for obtaining the calibration curve in a 1-20 Gy range. After irradiation the signal of each dosemeter was measured in an ESR spectrometer operating in the X-band (∼ 9.5 GHz) and the wideness of Alanine ESR spectra central line was correlated with the radiation dose. The wideness dose calibration curve resulted linear with a correlation coefficient 0.9996. The isodose curves obtained show a profile enough similar at comparing with the theoretical curves. (Author)

  5. Thermodynamics of DL-alanine solvation in water-dimethylsulfoxide mixtures at 298.15 K

    Science.gov (United States)

    Roy, S.; Mahali, K.; Mondal, S.; Dolui, B. K.

    2015-04-01

    In this study we mainly discuss the transfer Gibbs free energy Δ G {/t 0}( i) and Δ S {/t 0}( i)entropy of DL-alanine at 298.15 K and consequently the involved chemical transfer free energy (Δ G {/t,ch 0}( i)) and entropy ( TΔ S {/t,ch 0}( i)) in aqueous mixtures of dimethylsulfoxide are discussed to clarify the solvation chemistry of DL-alanine. For the evaluation of these energy terms, solubility of this amino acid has been measured by formol titrimetry at five equidistant temperatures i.e., from 288.15 to 308.15 K in different composition of this mixed solvent system. The various solvent parameters as well as thermodynamic parameters like molar volume, density, dipole moment and solvent diameter of this solvent system have also been reported here. The chemical effects of the transfer Gibbs energies (Δ G {/t,ch 0}( i)) and entropies of transfer ( TΔ S {/t,ch 0}( i)) have been obtained after elimination of cavity effect and dipole-dipole interaction effects from the total transfer energies. Here the chemical contribution of transfer energetics of DL-alanine is mainly guided by the composite effects of increased dispersion interaction, basicity effect and decreased acidity, hydrogen bonding effects, hydrophilic hydration and hydrophobic hydration of aqueous DMSO mixtures as compared to that of reference solvent, water.

  6. Application of the alanine detector to gamma-ray, X-ray and fast neutron dosimetry

    International Nuclear Information System (INIS)

    Waligorski, M.P.R.; Hansen, J.W.; Byrski, E.

    1987-01-01

    A dosimeter based on alanine has been developed at the INP in Krakow and at Risoe National Laboratory. Due to its near tissue-equivalence and stability of signal, measured using ESR spectrometry at room temperature, this free-radical amino-acid dosimetric system is particularly suitable for measuring X-ray, gamma-ray and fast neutron doses in the range 10-10 5 Gy. The relative effectiveness (with respect to 60 Co γ-rays) of the alanine dosimeter to 250 kVp X-rays and to cyclotron-produced fast neutrons (mean neutron energy 5.6 MeV) is measured to be 0.76± 0.06 and 0.60±0.05, respectively. The suitability of the alanine dosimeter for intercomparison gamma-ray dosimetry is also shown. The estimated absolute difference between 60 Co dosimetry at Risoe National Laboratory and at the Centre of Oncology in Krakow is about 5%, somewhat more than the experimental uncertainty. These results are based on ESR measurements performed in Krakow on about 25% of the exposed detectors. 28 refs., 2 figs., 3 tabs. (author)

  7. Molecular and phenotypic characterization of transgenic wheat and sorghum events expressing the barley alanine aminotransferase.

    Science.gov (United States)

    Peña, Pamela A; Quach, Truyen; Sato, Shirley; Ge, Zhengxiang; Nersesian, Natalya; Dweikat, Ismail M; Soundararajan, Madhavan; Clemente, Tom

    2017-12-01

    The expression of a barley alanine aminotransferase gene impacts agronomic outcomes in a C3 crop, wheat. The use of nitrogen-based fertilizers has become one of the major agronomic inputs in crop production systems. Strategies to enhance nitrogen assimilation and flux in planta are being pursued through the introduction of novel genetic alleles. Here an Agrobacterium-mediated approach was employed to introduce the alanine aminotransferase from barley (Hordeum vulgare), HvAlaAT, into wheat (Triticum aestivum) and sorghum (Sorghum bicolor), regulated by either constitutive or root preferred promoter elements. Plants harboring the transgenic HvAlaAT alleles displayed increased alanine aminotransferase (alt) activity. The enhanced alt activity impacted height, tillering and significantly boosted vegetative biomass relative to controls in wheat evaluated under hydroponic conditions, where the phenotypic outcome across these parameters varied relative to time of year study was conducted. Constitutive expression of HvAlaAT translated to elevation in wheat grain yield under field conditions. In sorghum, expression of HvAlaAT enhanced enzymatic activity, but no changes in phenotypic outcomes were observed. Taken together these results suggest that positive agronomic outcomes can be achieved through enhanced alt activity in a C3 crop, wheat. However, the variability observed across experiments under greenhouse conditions implies the phenotypic outcomes imparted by the HvAlaAT allele in wheat may be impacted by environment.

  8. Densities and solubilities of Glycylglycine and Glycyl-L-Alanine in Aqueous Electrolyte Solutions

    DEFF Research Database (Denmark)

    Breil, Martin Peter; Mollerup, Jørgen; Rudolph, E. Susanne J.

    2004-01-01

    Solubilities of glycylglycine and glycyl-L-alanine in aqueous electrolyte solutions containing 0-6 molal NaCl, 0-1 molal Na2SO4, and 0-1 molal (NH4)(2)SO4, have been determined experimentally at 298.15 K and atmospheric pressure. The solubility of glycylglycine and glycyl-L-alanine in pure water...... is 1.74 and 4.78 mol/kg of water, respectively. The solubility of glycylglycine in salt solutions of NaCl, Na2SO4, and (NH4)(2)SO4 show a moderate salting-in effect. The solubility of glycyl-L-alanine show a minor or no salting-in effect at low salt concentrations and a moderate salting-out effect...... at higher salt concentrations in NaCl and Na2SO4, and in (NH4)(2)SO4 the solubility is almost constant. The densities of the solutions have been determined experimentally, and the volume expansions by dissolving salt and dipeptide in water have been calculated. (C) 2003 Elsevier B.V. All rights reserved....

  9. Characterization of lithium formate EPR dosimeters for high dose applications – comparison with alanine

    DEFF Research Database (Denmark)

    Waldeland, Einar; Helt-Hansen, Jakob; Malinen, Eirik

    2011-01-01

    Lithium formate and l-α-alanine (alanine) EPR dosimeters were irradiated to doses from 100 Gy to 100 kGy. The irradiations were mainly performed at a Gammacell irradiator with dose rate of approximately 5.5 kGy h−1. Both the peak-to-peak amplitude of the first derivative EPR spectrum and the area...... irradiated to 1 kGy at temperatures from 11ºC to 40ºC were analyzed. By fitting an ‘exponential rise to maximum'-function to the dependence of the area under the EPR absorption spectrum on the dose, saturation doses of 53 kGy and 87 kGy for lithium formate and alanine, respectively, were found. Lower...... estimates were found when analyzing the dose dependence of the peak-to-peak amplitude. Furthermore, the peak-to-peak width was found to increase for doses above 10 kGy. No dose rate dependence for any of the studied materials was observed and the temperature coefficients at 25ºC (i.e. change in dosimeter...

  10. Alanine dosimetry using a spectrophotometric ferric-xylenol orange complex readout

    International Nuclear Information System (INIS)

    Laere, K. van; Buysse, J.; Berkvens, P.

    1989-01-01

    The spectrophotometric dosimetric method using the indirect oxidation of ferrous ions after dissolution of irradiated DL-and L-alanine has been thoroughly investigated with respect to its composition, read-out procedure and dose-response. Optimal concentration of 0.10 N H 2 SO 4 , 0.2 mM xylenol orange and 0.2 mM Fe 2+ were found, giving an absorption maximum at 547 nm. Standardization of chemical processing procedures allows a reproducibility better than 0.5%. The useful dose range has been extended to 0.03-12 kGy by means of slightly different read-out procedure. The quantitative concept of ''indirect yield'', G id , was introduced for this procedure as a measure of the indirect oxidation capacity of the radicals. It was found to be G id,0 (Fe 3+ ) 7.1 ions/100 eV transferred into the alanine. The spectrophotometric readout combines the highly advantageous use of alanine as a dosemeter with the straightforwardness, accuracy and low costs of the chemical procedure. (author)

  11. Survivability and reactivity of glycine and alanine in early oceans: effects of meteorite impacts.

    Science.gov (United States)

    Umeda, Yuhei; Fukunaga, Nao; Sekine, Toshimori; Furukawa, Yoshihiro; Kakegawa, Takeshi; Kobayashi, Takamichi; Nakazawa, Hiromoto

    2016-01-01

    Prebiotic oceans might have contained abundant amino acids, and were subjected to meteorite impacts, especially during the late heavy bombardment. It is so far unknown how meteorite impacts affected amino acids in the early oceans. Impact experiments were performed under the conditions where glycine was synthesized from carbon, ammonia, and water, using aqueous solutions containing (13)C-labeled glycine and alanine. Selected amino acids and amines in samples were analyzed with liquid chromatography-mass spectrometry (LC/MS). In particular, the (13)C-labeled reaction products were analyzed to distinguish between run products and contaminants. The results revealed that both amino acids survived partially in the early ocean through meteorite impacts, that part of glycine changed into alanine, and that large amounts of methylamine and ethylamine were formed. Fast decarboxylation was confirmed to occur during such impact processes. Furthermore, the formation of n-butylamine, detected only in the samples recovered from the solutions with additional nitrogen and carbon sources of ammonia and benzene, suggests that chemical reactions to form new biomolecules can proceed through marine impacts. Methylamine and ethylamine from glycine and alanine increased considerably in the presence of hematite rather than olivine under similar impact conditions. These results also suggest that amino acids present in early oceans can contribute further to impact-induced reactions, implying that impact energy plays a potential role in the prebiotic formation of various biomolecules, although the reactions are complicated and depend upon the chemical environments as well.

  12. Buried interfaces - A systematic study to characterize an adhesive interface at multiple scales

    Science.gov (United States)

    Haubrich, Jan; Löbbecke, Miriam; Watermeyer, Philipp; Wilde, Fabian; Requena, Guillermo; da Silva, Julio

    2018-03-01

    A comparative study of a model adhesive interface formed between laser-pretreated Ti15-3-3-3 and the thermoplastic polymer PEEK has been carried out in order to characterize the interfaces' structural details and the infiltration of the surface nano-oxide by the polymer at multiple scales. Destructive approaches such as scanning and transmission electron microscopy of microsections prepared by focused ion beam, and non-destructive imaging approaches including laser scanning and scanning electron microscopy of pretreated surfaces as well as synchrotron computed tomography techniques (micro- and ptychographic tomographies) were employed for resolving the large, μm-sized melt-structures and the fine nano-oxide substructure within the buried interface. Scanning electron microscopy showed that the fine, open-porous nano-oxide homogeneously covers the larger macrostructure features which in turn cover the joint surface. The open-porous nano-oxide forming the interface itself appears to be fully infiltrated and wetted by the polymer. No voids or even channels were detected down to the respective resolution limits of scanning and transmission electron microscopy.

  13. Interface Simulation Distances

    Directory of Open Access Journals (Sweden)

    Pavol Černý

    2012-10-01

    Full Text Available The classical (boolean notion of refinement for behavioral interfaces of system components is the alternating refinement preorder. In this paper, we define a distance for interfaces, called interface simulation distance. It makes the alternating refinement preorder quantitative by, intuitively, tolerating errors (while counting them in the alternating simulation game. We show that the interface simulation distance satisfies the triangle inequality, that the distance between two interfaces does not increase under parallel composition with a third interface, and that the distance between two interfaces can be bounded from above and below by distances between abstractions of the two interfaces. We illustrate the framework, and the properties of the distances under composition of interfaces, with two case studies.

  14. Laser Scanning in Forests

    Directory of Open Access Journals (Sweden)

    Håkan Olsson

    2012-09-01

    Full Text Available The introduction of Airborne Laser Scanning (ALS to forests has been revolutionary during the last decade. This development was facilitated by combining earlier ranging lidar discoveries [1–5], with experience obtained from full-waveform ranging radar [6,7] to new airborne laser scanning systems which had components such as a GNSS receiver (Global Navigation Satellite System, IMU (Inertial Measurement Unit and a scanning mechanism. Since the first commercial ALS in 1994, new ALS-based forest inventory approaches have been reported feasible for operational activities [8–12]. ALS is currently operationally applied for stand level forest inventories, for example, in Nordic countries. In Finland alone, the adoption of ALS for forest data collection has led to an annual savings of around 20 M€/year, and the work is mainly done by companies instead of governmental organizations. In spite of the long implementation times and there being a limited tradition of making changes in the forest sector, laser scanning was commercially and operationally applied after about only one decade of research. When analyzing high-ranked journal papers from ISI Web of Science, the topic of laser scanning of forests has been the driving force for the whole laser scanning research society over the last decade. Thus, the topic “laser scanning in forests” has provided a significant industrial, societal and scientific impact. [...

  15. Bone scan in pediatrics

    International Nuclear Information System (INIS)

    Gordon, I.; Peters, A.M.

    1987-01-01

    In 1984, a survey carried out in 21 countries in Europe showed that bone scintigraphy comprised 16% of all paediatric radioisotope scans. Although the value of bone scans in paediatrics is potentially great, their quality varies greatly, and poor-quality images are giving this valuable technique a bad reputation. The handling of children requires a sensitive staff and the provision of a few simple inexpensive items of distraction. Attempting simply to scan a child between two adult patients in a busy general department is a recipe for an unhappy, uncooperative child with the probable result of poor images. The intravenous injection of isotope should be given adjacent to the gamma camera room, unless dynamic scans are required, so that the child does not associate the camera with the injection. This injection is best carried out by someone competent in paediatric venipunture; the entire procedure should be explained to the child and parent, who should remain with child throughout. It is naive to think that silence makes for a cooperative child. The sensitivity of bone-seeking radioisotope tracers and the marked improvement in gamma camera resolution has allowed the bone scanning to become an integrated technique in the assessment of children suspected of suffering from pathological bone conditions. The tracer most commonly used for routine bone scanning is 99m Tc diphosphonate (MDP); other isotopes used include 99m Tc colloid for bone marrow scans and 67 Ga citrate and 111 In white blood cells ( 111 In WBC) for investigation of inflammatory/infective lesions

  16. Prolonged continuous intravenous infusion of the dipeptide L-alanine- L-glutamine significantly increases plasma glutamine and alanine without elevating brain glutamate in patients with severe traumatic brain injury.

    Science.gov (United States)

    Nägeli, Mirjam; Fasshauer, Mario; Sommerfeld, Jutta; Fendel, Angela; Brandi, Giovanna; Stover, John F

    2014-07-02

    Low plasma glutamine levels are associated with worse clinical outcome. Intravenous glutamine infusion dose- dependently increases plasma glutamine levels, thereby correcting hypoglutaminemia. Glutamine may be transformed to glutamate which might limit its application at a higher dose in patients with severe traumatic brain injury (TBI). To date, the optimal glutamine dose required to normalize plasma glutamine levels without increasing plasma and cerebral glutamate has not yet been defined. Changes in plasma and cerebral glutamine, alanine, and glutamate as well as indirect signs of metabolic impairment reflected by increased intracranial pressure (ICP), lactate, lactate-to-pyruvate ratio, electroencephalogram (EEG) activity were determined before, during, and after continuous intravenous infusion of 0.75 g L-alanine-L-glutamine which was given either for 24 hours (group 1, n = 6) or 5 days (group 2, n = 6) in addition to regular enteral nutrition. Lab values including nitrogen balance, urea and ammonia were determined daily. Continuous L-alanine-L-glutamine infusion significantly increased plasma and cerebral glutamine as well as alanine levels, being mostly sustained during the 5 day infusion phase (plasma glutamine: from 295 ± 62 to 500 ± 145 μmol/ l; brain glutamine: from 183 ± 188 to 549 ± 120 μmol/ l; plasma alanine: from 327 ± 91 to 622 ± 182 μmol/ l; brain alanine: from 48 ± 55 to 89 ± 129 μmol/ l; p alanine-L-glutamine infusion (0.75 g/ kg/ d up to 5 days) increased plasma and brain glutamine and alanine levels. This was not associated with elevated glutamate or signs of potential glutamate-mediated cerebral injury. The increased nitrogen load should be considered in patients with renal and hepatic dysfunction. Clinicaltrials.gov NCT02130674. Registered 5 April 2014.

  17. Solid Surfaces, Interfaces and Thin Films

    CERN Document Server

    Lüth, Hans

    2010-01-01

    This book emphasises both experimental and theoretical aspects of surface, interface and thin film physics. As in previous editions the preparation of surfaces and thin films, their atomic and morphological, their vibronic and electronic properties as well as fundamentals of adsorption are treated. Because of their importance in modern information technology and nanostructure physics particular emphasis is paid to electronic surface and interface states, semiconductor space charge layers and heterostructures as well as to superconductor/semiconductor interfaces and magnetic thin films. The latter topic was significantly extended in this new edition by more details about the giant magnetoresistance and a section about the spin-transfer torque mechanism including one new problem as exercise. Two new panels about Kerr-effect and spin-polarized scanning tunnelling microscopy were added, too. Furthermore, the meanwhile important group III-nitride surfaces and high-k oxide/semiconductor interfaces are shortly discu...

  18. Combinatorial Alanine Substitution Enables Rapid Optimization of Cytochrome P450BM3 for Selective Hydroxylation of Large Substrates

    KAUST Repository

    Lewis, Jared C.; Mantovani, Simone M.; Fu, Yu; Snow, Christopher D.; Komor, Russell S.; Wong , Chi-Huey; Arnold, Frances H.

    2010-01-01

    Made for each other: Combinatorial alanine substitution of active site residues in a thermostable cytochrome P450BM3 variant was used to generate an enzyme that is active with large substrates. Selective hydroxylation of methoxymethylated

  19. Probing the energy landscape of alanine dipeptide and decalanine using temperature as a tunable parameter in molecular dynamics

    International Nuclear Information System (INIS)

    Chatterjee, A; Bhattacharya, S

    2016-01-01

    We perform several molecular dynamics (MD) calculations of solvated alanine dipeptide and decalanine in vacuum with temperature as a tunable parameter and in the process, generate Markov state models (MSMs) at each temperature. An interesting observation that the kinetic rates appear to obey the Arrhenius rate law allows us to predict the dynamics of alanine dipeptide at 300 K at the microsecond timescales using the nanoseconds long high temperature calculations without actually performing MD simulations at 300 K. We conclude that the energy landscape of alanine dipeptide contains superbasins deeper than k B T and determine the energy barriers associated with the moves from the Arrhenius rate expression. Similar insights regarding the energy landscape associated with folding/unfolding pathways of a deca-alanine molecule are obtained using kinetic rates calculated at different temperatures. (paper)

  20. Carnosine and anserine homeostasis in skeletal muscle and heart is controlled by β‐alanine transamination

    Science.gov (United States)

    Blancquaert, Laura; Baba, Shahid P.; Kwiatkowski, Sebastian; Stautemas, Jan; Stegen, Sanne; Barbaresi, Silvia; Chung, Weiliang; Boakye, Adjoa A.; Hoetker, J. David; Bhatnagar, Aruni; Delanghe, Joris; Vanheel, Bert; Veiga‐da‐Cunha, Maria; Derave, Wim

    2016-01-01

    Key points Using recombinant DNA technology, the present study provides the first strong and direct evidence indicating that β‐alanine is an efficient substrate for the mammalian transaminating enzymes 4‐aminobutyrate‐2‐oxoglutarate transaminase and alanine‐glyoxylate transaminase.The concentration of carnosine and anserine in murine skeletal and heart muscle depends on circulating availability of β‐alanine, which is in turn controlled by degradation of β‐alanine in liver and kidney.Chronic oral β‐alanine supplementation is a popular ergogenic strategy in sports because it can increase the intracellular carnosine concentration and subsequently improve the performance of high‐intensity exercises. The present study can partly explain why the β‐alanine supplementation protocol is so inefficient, by demonstrating that exogenous β‐alanine can be effectively routed toward oxidation. Abstract The metabolic fate of orally ingested β‐alanine is largely unknown. Chronic β‐alanine supplementation is becoming increasingly popular for improving high‐intensity exercise performance because it is the rate‐limiting precursor of the dipeptide carnosine (β‐alanyl‐l‐histidine) in muscle. However, only a small fraction (3–6%) of the ingested β‐alanine is used for carnosine synthesis. Thus, the present study aimed to investigate the putative contribution of two β‐alanine transamination enzymes, namely 4‐aminobutyrate‐2‐oxoglutarate transaminase (GABA‐T) and alanine‐glyoxylate transaminase (AGXT2), to the homeostasis of carnosine and its methylated analogue anserine. We found that, when transfected into HEK293T cells, recombinant mouse and human GABA‐T and AGXT2 are able to transaminate β‐alanine efficiently. The reaction catalysed by GABA‐T is inhibited by vigabatrin, whereas both GABA‐T and AGXT2 activity is inhibited by aminooxyacetic acid (AOA). Both GABA‐T and AGXT2 are highly expressed in the mouse liver and

  1. Determination of muscle protein synthesis rates in fish using (2)H2O and (2)H NMR analysis of alanine.

    Science.gov (United States)

    Marques, Cátia; Viegas, Filipa; Rito, João; Jones, John; Viegas, Ivan

    2016-09-15

    Following administration of deuterated water ((2)H2O), the fractional synthetic rate (FSR) of a given endogenous protein can be estimated by (2)H-enrichment quantification of its alanine residues. Currently, this is measured by mass spectrometry following a derivatization procedure. Muscle FSR was measured by (1)H/(2)H NMR analysis of alanine from seabass kept for 6 days in 5% (2)H-enriched saltwater, following acid hydrolysis and amino acid isolation by cation-exchange chromatography of muscle tissue. The analysis is simple and robust, and provides precise measurements of excess alanine (2)H-enrichment in the 0.1-0.4% range from 50 mmol of alanine recovered from muscle protein. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Admittance Scanning for Whole Column Detection.

    Science.gov (United States)

    Stamos, Brian N; Dasgupta, Purnendu K; Ohira, Shin-Ichi

    2017-07-05

    Whole column detection (WCD) is as old as chromatography itself. WCD requires an ability to interrogate column contents from the outside. Other than the obvious case of optical detection through a transparent column, admittance (often termed contactless conductance) measurements can also sense changes in the column contents (especially ionic content) from the outside without galvanic contact with the solution. We propose here electromechanically scanned admittance imaging and apply this to open tubular (OT) chromatography. The detector scans across the column; the length resolution depends on the scanning velocity and the data acquisition frequency, ultimately limited by the physical step resolution (40 μm in the present setup). Precision equal to this step resolution was observed for locating an interface between two immiscible liquids inside a 21 μm capillary. Mechanically, the maximum scanning speed was 100 mm/s, but at 1 kHz sampling rate and a time constant of 25 ms, the highest practical scan speed (no peak distortion) was 28 mm/s. At scanning speeds of 0, 4, and 28 mm/s, the S/N for 180 pL (zone length of 1.9 mm in a 11 μm i.d. column) of 500 μM KCl injected into water was 6450, 3850, and 1500, respectively. To facilitate constant and reproducible contact with the column regardless of minor variations in outer diameter, a double quadrupole electrode system was developed. Columns of significant length (>1 m) can be readily scanned. We demonstrate its applicability with both OT and commercial packed columns and explore uniformity of retention along a column, increasing S/N by stopped-flow repeat scans, etc. as unique applications.

  3. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... for a thyroid scan is 30 minutes or less. Thyroid Uptake You will be given radioactive iodine ( ... for each thyroid uptake is five minutes or less. top of page What will I experience during ...

  4. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... evaluate changes in the gland following medication use, surgery, radiotherapy or chemotherapy top of page How should ... such as an x-ray or CT scan, surgeries or treatments using iodinated contrast material within the ...

  5. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... abnormal was found, and should not be a cause of concern for you. If you had an ... abnormal was found, and should not be a cause of concern for you. Actual scanning time for ...

  6. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    Details are given of a tomographic scanning apparatus, with particular reference to a multiplexer slip ring means for receiving output from the detectors and enabling interfeed to the image reconstruction station. (U.K.)

  7. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    Details are presented of a tomographic scanning apparatus, its rotational assembly, and the control and circuit elements, with particular reference to the amplifier and multiplexing circuits enabling detector signal calibration. (U.K.)

  8. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    This patent specification relates to a tomographic scanning apparatus using a fan beam and digital output signal, and particularly to the design of the gas-pressurized ionization detection system. (U.K.)

  9. Pediatric CT Scans

    Science.gov (United States)

    The Radiation Epidemiology Branch and collaborators have initiated a retrospective cohort study to evaluate the relationship between radiation exposure from CT scans conducted during childhood and adolescence and the subsequent development of cancer.

  10. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... which are encased in metal and plastic and most often shaped like a box, attached to a ... will I experience during and after the procedure? Most thyroid scan and thyroid uptake procedures are painless. ...

  11. Heart CT scan

    Science.gov (United States)

    ... make to decrease the risk of heart disease. Risks Risks of CT scans include: Being exposed to ... urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows ...

  12. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... eat for several hours before your exam because eating can affect the accuracy of the uptake measurement. ... often unattainable using other imaging procedures. For many diseases, nuclear medicine scans yield the most useful information ...

  13. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) is ... thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that uses ...

  14. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... that help physicians diagnose and evaluate medical conditions. These imaging scans use radioactive materials called radiopharmaceuticals or ... or had thyroid cancer. A physician may perform these imaging tests to: determine if the gland is ...

  15. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Because nuclear medicine procedures are able to pinpoint molecular activity within the body, they offer the potential ... or imaging device that produces pictures and provides molecular information. The thyroid scan and thyroid uptake provide ...

  16. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Actual scanning time for each thyroid uptake is five minutes or less. top of page What will ... diagnostic procedures have been used for more than five decades, and there are no known long-term ...

  17. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... top of page Additional Information and Resources RTAnswers.org Radiation Therapy for Head and Neck Cancer top ... Scan and Uptake Sponsored by Please note RadiologyInfo.org is not a medical facility. Please contact your ...

  18. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... often unattainable using other imaging procedures. For many diseases, nuclear medicine scans yield the most useful information needed to make a diagnosis or to determine appropriate treatment, if any. Nuclear medicine is less expensive and ...

  19. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... the gamma camera and single-photon emission-computed tomography (SPECT). The gamma camera, also called a scintillation ... high as with other imaging techniques, such as CT or MRI. However, nuclear medicine scans are more ...

  20. Scanning Auger Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — A JEOL model 7830F field emission source, scanning Auger microscope.Specifications / Capabilities:Ultra-high vacuum (UHV), electron gun range from 0.1 kV to 25 kV,...

  1. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... as an overactive thyroid gland, a condition called hyperthyroidism , cancer or other growths assess the nature of ... an x-ray or CT scan, surgeries or treatments using iodinated contrast material within the last two ...

  2. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... painless. However, during the thyroid scan, you may feel uncomfortable when lying completely still with your head ... When the radiotracer is given intravenously, you will feel a slight pin prick when the needle is ...

  3. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... energy. top of page What are some common uses of the procedure? The thyroid scan is used ... community, you can search the ACR-accredited facilities database . This website does not provide cost information. The ...

  4. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... scan and thyroid uptake provide information about the structure and function of the thyroid. The thyroid is ... computer, create pictures offering details on both the structure and function of organs and tissues in your ...

  5. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... found, and should not be a cause of concern for you. If you had an intravenous line ... found, and should not be a cause of concern for you. Actual scanning time for each thyroid ...

  6. Body CT (CAT Scan)

    Science.gov (United States)

    ... a CT scan can be reformatted in multiple planes, and can even generate three-dimensional images. These ... other medical conditions and whether you have a history of heart disease, asthma, diabetes, kidney disease or ...

  7. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... the gland following medication use, surgery, radiotherapy or chemotherapy top of page How should I prepare? You ... You will receive specific instructions based on the type of scan you are undergoing. top of page ...

  8. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... Uptake? A thyroid scan is a type of nuclear medicine imaging. The radioactive iodine uptake test (RAIU) ... of thyroid function, but does not involve imaging. Nuclear medicine is a branch of medical imaging that ...

  9. Tomographic scanning apparatus

    International Nuclear Information System (INIS)

    1981-01-01

    This patent specification describes a tomographic scanning apparatus, with particular reference to the adjustable fan beam and its collimator system, together with the facility for taking a conventional x-radiograph without moving the patient. (U.K.)

  10. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... exam of any medications you are taking, including vitamins and herbal supplements. You should also inform them ... of scan you are undergoing. top of page What does the equipment look like? The special camera ...

  11. The Scanning Optical Microscope.

    Science.gov (United States)

    Sheppard, C. J. R.

    1978-01-01

    Describes the principle of the scanning optical microscope and explains its advantages over the conventional microscope in the improvement of resolution and contrast, as well as the possibility of producing a picture from optical harmonies generated within the specimen.

  12. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... the gland following medication use, surgery, radiotherapy or chemotherapy top of page How should I prepare? You ... but is often performed on hospitalized patients as well. Thyroid Scan You will be positioned on an ...

  13. Assessment of Metabolic Changes in Mycobacterium smegmatis Wild-Type and alr Mutant Strains: Evidence of a New Pathway of d-Alanine Biosynthesis.

    Science.gov (United States)

    Marshall, Darrell D; Halouska, Steven; Zinniel, Denise K; Fenton, Robert J; Kenealy, Katie; Chahal, Harpreet K; Rathnaiah, Govardhan; Barletta, Raúl G; Powers, Robert

    2017-03-03

    In mycobacteria, d-alanine is an essential precursor for peptidoglycan biosynthesis. The only confirmed enzymatic pathway to form d-alanine is through the racemization of l-alanine by alanine racemase (Alr, EC 5.1.1.1). Nevertheless, the essentiality of Alr in Mycobacterium tuberculosis and Mycobacterium smegmatis for cell survivability in the absence of d-alanine has been a point of controversy with contradictory results reported in the literature. To address this issue, we examined the effects of alr inactivation on the cellular metabolism of M. smegmatis. The M. smegmatis alr insertion mutant TAM23 exhibited essentially identical growth to wild-type mc 2 155 in the absence of d-alanine. NMR metabolomics revealed drastically distinct phenotypes between mc 2 155 and TAM23. A metabolic switch was observed for TAM23 as a function of supplemented d-alanine. In the absence of d-alanine, the metabolic response directed carbon through an unidentified transaminase to provide the essential d-alanine required for survival. The process is reversed when d-alanine is available, in which the d-alanine is directed to peptidoglycan biosynthesis. Our results provide further support for the hypothesis that Alr is not an essential function of M. smegmatis and that specific Alr inhibitors will have no bactericidal action.

  14. Effects of high-salinity seawater acclimation on the levels of D-alanine in the muscle and hepatopancreas of kuruma prawn, Marsupenaeus japonicus.

    Science.gov (United States)

    Yoshikawa, Naoko; Yokoyama, Masahumi

    2015-12-10

    Changes in D- and L-alanine contents were determined in the muscle and hepatopancreas of kuruma prawn Marsupenaeus japonicus, during acclimation from seawater containing 100% salinity to artificial seawater containing 150% salinity. In the hepatopancreas, contents of both amino acids increased by approximately threefold. The activity of alanine racemase, which catalyzes the interconversion of D- and L-alanine, also increased in the high-salinity seawater. In addition, the expression of the gene encoding alanine racemase increased in the hepatopancreas with an increase in the alanine racemase activity. These data indicate that the biosynthesis of D- and L-alanine is controlled by the gene expression level of alanine racemase, and D-alanine in the hepatopancreas functions as a major osmolyte for isosmotic regulation. In contrast, the content of D-alanine and alanine racemase activity did not change in the muscle during hyper-osmotic acclimation. Therefore, we suggest that D-alanine, which exists in the several tissues of M. japonicus, is considered to be utilized in some different physiological phenomena in different tissues. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Brain–muscle interface

    Indian Academy of Sciences (India)

    2011-05-16

    May 16, 2011 ... Clipboard: Brain–muscle interface: The next-generation BMI. Radhika Rajan Neeraj Jain ... Keywords. Assistive devices; brain–machine interface; motor cortex; paralysis; spinal cord injury ... Journal of Biosciences | News ...

  16. Spectrum scanning of monochromator by microcontroller ATtiny 2313

    International Nuclear Information System (INIS)

    Veklich, A.M.; Boretskij, V.F.; Kleshich, M.M.; Fesenko, S.O.

    2009-01-01

    The results of interface developing on the base of Atmel microcontroller ATtiny 2313 are shown. This device is dedicated to the spectrum scanning of monochromators by the step motor. The design principles of motor control scheme are analyzed. The original algorithm of microcontroller program was suggested and realized. The principal performance availability of the USB interface for the purpose of the device control by the personal computer is considered.

  17. Garbage collector interface

    OpenAIRE

    Ive, Anders; Blomdell, Anders; Ekman, Torbjörn; Henriksson, Roger; Nilsson, Anders; Nilsson, Klas; Robertz, Sven

    2002-01-01

    The purpose of the presented garbage collector interface is to provide a universal interface for many different implementations of garbage collectors. This is to simplify the integration and exchange of garbage collectors, but also to support incremental, non-conservative, and thread safe implementations. Due to the complexity of the interface, it is aimed at code generators and preprocessors. Experiences from ongoing implementations indicate that the garbage collector interface successfully ...

  18. Microcomputer interfacing and applications

    CERN Document Server

    Mustafa, M A

    1990-01-01

    This is the applications guide to interfacing microcomputers. It offers practical non-mathematical solutions to interfacing problems in many applications including data acquisition and control. Emphasis is given to the definition of the objectives of the interface, then comparing possible solutions and producing the best interface for every situation. Dr Mustafa A Mustafa is a senior designer of control equipment and has written many technical articles and papers on the subject of computers and their application to control engineering.

  19. Laser scanning of a recirculation zone on the Bolund escarpment

    DEFF Research Database (Denmark)

    Mann, Jakob; Angelou, Nikolas; Sjöholm, Mikael

    2014-01-01

    Rapid variations in the height of the recirculation zone are measured with a scanning wind lidar over a small escarpment on the Bolund Peninsula. The lidar is essentially a continuous-wave laser Doppler anemometer with the capability of rapidly changing the focus distance and the beam direction....... The instrument measures the line-of-sight velocity 390 times per second and scans ten wind profiles from the ground up to seven meters per second. We observe a sharp interface between slow and fast moving fluid after the escarpment, and the interface is moving rapidly up and down. This implies that the position...

  20. Interface magnons. Magnetic superstructure

    International Nuclear Information System (INIS)

    Djafari-Rouhani, B.; Dobrzynski, L.

    1975-01-01

    The localized magnons at an interface between two Heisenberg ferromagnets are studied with a simple model. The effect of the coupling at the interface on the existence condition for the localized modes, the dispersion laws and the possible occurrence of magnetic superstructures due to soft modes are investigated. Finally a comparison is made with the similar results obtained for interface phonons [fr

  1. Water at Interfaces

    DEFF Research Database (Denmark)

    Björneholm, Olle; Hansen, Martin Hangaard; Hodgson, Andrew

    2016-01-01

    The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives...

  2. User Interface History

    DEFF Research Database (Denmark)

    Jørgensen, Anker Helms; Myers, Brad A

    2008-01-01

    User Interfaces have been around as long as computers have existed, even well before the field of Human-Computer Interaction was established. Over the years, some papers on the history of Human-Computer Interaction and User Interfaces have appeared, primarily focusing on the graphical interface e...

  3. Graphical Interfaces for Simulation.

    Science.gov (United States)

    Hollan, J. D.; And Others

    This document presents a discussion of the development of a set of software tools to assist in the construction of interfaces to simulations and real-time systems. Presuppositions to the approach to interface design that was used are surveyed, the tools are described, and the conclusions drawn from these experiences in graphical interface design…

  4. Huffman and linear scanning methods with statistical language models.

    Science.gov (United States)

    Roark, Brian; Fried-Oken, Melanie; Gibbons, Chris

    2015-03-01

    Current scanning access methods for text generation in AAC devices are limited to relatively few options, most notably row/column variations within a matrix. We present Huffman scanning, a new method for applying statistical language models to binary-switch, static-grid typing AAC interfaces, and compare it to other scanning options under a variety of conditions. We present results for 16 adults without disabilities and one 36-year-old man with locked-in syndrome who presents with complex communication needs and uses AAC scanning devices for writing. Huffman scanning with a statistical language model yielded significant typing speedups for the 16 participants without disabilities versus any of the other methods tested, including two row/column scanning methods. A similar pattern of results was found with the individual with locked-in syndrome. Interestingly, faster typing speeds were obtained with Huffman scanning using a more leisurely scan rate than relatively fast individually calibrated scan rates. Overall, the results reported here demonstrate great promise for the usability of Huffman scanning as a faster alternative to row/column scanning.

  5. Status report of the ESR/alanine project of the IAEA Dosimetry Laboratory

    International Nuclear Information System (INIS)

    Girzikowsky, R.

    1990-01-01

    The main tasks of the Dosimetry Laboratory of the IAEA are in the field of therapy-level dosimetry. Other dose ranges, i.e. protection-level standardization and calibration, are partly covered, too. On high-dose level the laboratory has been offering a Fricke-dosimetry service to Member States on request since 1965. In 1985 the Dosimetry Section has initiated an International Dose Assurance Service (IDAS). This service is an important part of the Agency's high-dose standardization programme and is based on Electron-Spin-Resonance (ESR) analysis of radiation-induced free radicals in alanine. This ESR/alanine dosimetry system was initially developed for high-dose application by GSF/Munich as the Agency's outside contractor. Although efforts were undertaken to equip the Agency Laboratory with an ESR analyzer since 1984, the purchase of an adequate unit was postponed until the end of 1988. From the date of establishment of the IDAS programme until today, the handling of all technical aspects, i.e. dosimeter production and evaluation was and is carried out by GSP/Munich under IAEA contract. As mentioned above, the IAEA Dosimetry Laboratory is in possession of its own ESR analyzer since December 1988. It was then installed in May 1989. Only one staff member of the laboratory was assigned to this project. He made himself acquainted with the analyzer, the measuring technique, and the application of alanine as dosimeter material. The ESR spectrometric analyzer is a CW ESR type ESP 300 manufactured by Bruker GmbH/FRG. It consists of a 9''/2,7 kW magnet, an X-band microwave bridge, a field regulator unit, a signal channel unit and a data system ESP 1620 based on the 68020 CPU. The probe material selected for measurement of concentration of radiation-induced free radicals is L-Alanine. This amino acid is a suitable material for transfer dosimeters due to its properties, i.e. wide sensitivity range (10 Gy to 100 kGy), energy independence for high-energy photons and electron

  6. Quantization of interface currents

    Energy Technology Data Exchange (ETDEWEB)

    Kotani, Motoko [AIMR, Tohoku University, Sendai (Japan); Schulz-Baldes, Hermann [Department Mathematik, Universität Erlangen-Nürnberg, Erlangen (Germany); Villegas-Blas, Carlos [Instituto de Matematicas, Cuernavaca, UNAM, Cuernavaca (Mexico)

    2014-12-15

    At the interface of two two-dimensional quantum systems, there may exist interface currents similar to edge currents in quantum Hall systems. It is proved that these interface currents are macroscopically quantized by an integer that is given by the difference of the Chern numbers of the two systems. It is also argued that at the interface between two time-reversal invariant systems with half-integer spin, one of which is trivial and the other non-trivial, there are dissipationless spin-polarized interface currents.

  7. Water at Interfaces.

    Science.gov (United States)

    Björneholm, Olle; Hansen, Martin H; Hodgson, Andrew; Liu, Li-Min; Limmer, David T; Michaelides, Angelos; Pedevilla, Philipp; Rossmeisl, Jan; Shen, Huaze; Tocci, Gabriele; Tyrode, Eric; Walz, Marie-Madeleine; Werner, Josephina; Bluhm, Hendrik

    2016-07-13

    The interfaces of neat water and aqueous solutions play a prominent role in many technological processes and in the environment. Examples of aqueous interfaces are ultrathin water films that cover most hydrophilic surfaces under ambient relative humidities, the liquid/solid interface which drives many electrochemical reactions, and the liquid/vapor interface, which governs the uptake and release of trace gases by the oceans and cloud droplets. In this article we review some of the recent experimental and theoretical advances in our knowledge of the properties of aqueous interfaces and discuss open questions and gaps in our understanding.

  8. Free Energy Landscapes of Alanine Oligopeptides in Rigid-Body and Hybrid Water Models.

    Science.gov (United States)

    Nayar, Divya; Chakravarty, Charusita

    2015-08-27

    Replica exchange molecular dynamics is used to study the effect of different rigid-body (mTIP3P, TIP4P, SPC/E) and hybrid (H1.56, H3.00) water models on the conformational free energy landscape of the alanine oligopeptides (acAnme and acA5nme), in conjunction with the CHARMM22 force field. The free energy landscape is mapped out as a function of the Ramachandran angles. In addition, various secondary structure metrics, solvation shell properties, and the number of peptide-solvent hydrogen bonds are monitored. Alanine dipeptide is found to have similar free energy landscapes in different solvent models, an insensitivity which may be due to the absence of possibilities for forming i-(i + 4) or i-(i + 3) intrapeptide hydrogen bonds. The pentapeptide, acA5nme, where there are three intrapeptide backbone hydrogen bonds, shows a conformational free energy landscape with a much greater degree of sensitivity to the choice of solvent model, though the three rigid-body water models differ only quantitatively. The pentapeptide prefers nonhelical, non-native PPII and β-sheet populations as the solvent is changed from SPC/E to the less tetrahedral liquid (H1.56) to an LJ-like liquid (H3.00). The pentapeptide conformational order metrics indicate a preference for open, solvent-exposed, non-native structures in hybrid solvent models at all temperatures of study. The possible correlations between the properties of solvent models and secondary structure preferences of alanine oligopeptides are discussed, and the competition between intrapeptide, peptide-solvent, and solvent-solvent hydrogen bonding is shown to be crucial in the relative free energies of different conformers.

  9. Accumulation of D- vs. L-isomers of alanine and leucine in rat prostatic adenocarcinoma

    International Nuclear Information System (INIS)

    Conti, P.S.; Schmall, B.; Bigler, R.E.; Zanzonico, P.B.; Kleinert, E.; Whitmore, W.F. Jr.

    1985-01-01

    It has been reported that tumor tissue may accumulate some D-amino acids preferentially over the L-isomers. In order to investigate the potential use of carbon-11 labeled amino acid isomers for in vivo tumor studies with positron emission tomography in patients, the tissue distributions of alanine and leucine, substrates for the A-type and L-type amino acid transport systems, respectively, were studied in Copenhagen rates bearing the Dunning R3327G prostatic adenocarcinoma. The authors have previously reported differences in the accumulation of A-type vs. L-type amino acids in rat prostatic adenocarcinoma and normal tissues. All compounds were labeled with C-14 in the carboxyl position with specific activities of 30.0-56.6 mCi/mmol. Higher levels of C-14 activity (Relative Concentration (RC)=dpm found per gm tissue + dpm inject per gm animal mass) were observed in tumor tissue using D-alanine (0.71) compared to L- (0.21) or DL-alanine (0.27) at 45 min post-injection. While tumor/prostate and tumor/liver ratios were above 2 for all three substrates, tumor/blood and tumor/muscle were above one for only the D-isomer. Comparisons made with D-, L-, and DL-leucine also demonstrated a higher level of RC in tumor tissue with the D-isomer (0.84) vs. the L-(0.66) and DL-leucine (0.63). In this case, however, tumor/blood, tumor/prostate, and tumor/muscle ratios were above one for all three substrates, while tumor/liver ratios were below one. These results support the observation of a preferential accumulation of D-amino acids in tumor tissue over the natural L-isomers. Observed differences in the accumulation of the isomers in normal tissues are discussed

  10. Shape-changing interfaces:

    DEFF Research Database (Denmark)

    Rasmussen, Majken Kirkegård; Pedersen, Esben Warming; Petersen, Marianne Graves

    2015-01-01

    Shape change is increasingly used in physical user interfaces, both as input and output. Yet, the progress made and the key research questions for shape-changing interfaces are rarely analyzed systematically. We review a sample of existing work on shape-changing interfaces to address these shortc......Shape change is increasingly used in physical user interfaces, both as input and output. Yet, the progress made and the key research questions for shape-changing interfaces are rarely analyzed systematically. We review a sample of existing work on shape-changing interfaces to address...... these shortcomings. We identify eight types of shape that are transformed in various ways to serve both functional and hedonic design purposes. Interaction with shape-changing interfaces is simple and rarely merges input and output. Three questions are discussed based on the review: (a) which design purposes may...

  11. Preoperative bone scans

    International Nuclear Information System (INIS)

    Charkes, N.D.; Malmud, L.S.; Caswell, T.; Goldman, L.; Hall, J.; Lauby, V.; Lightfoot, W.; Maier, W.; Rosemond, G.

    1975-01-01

    Strontium nitrate Sr-87m bone scans were made preoperatively in a group of women with suspected breast cancer, 35 of whom subsequently underwent radical mastectomy. In 3 of the 35 (9 percent), the scans were abnormal despite the absence of clinical or roentgenographic evidence of metastatic disease. All three patients had extensive axillary lymph node involvement by tumor, and went on to have additional bone metastases, from which one died. Roentgenograms failed to detect the metastases in all three. Occult bone metastases account in part for the failure of radical mastectomy to cure some patients with breast cancer. It is recommended that all candidates for radical mastectomy have a preoperative bone scan. (U.S.)

  12. Frequency scanning microstrip antennas

    DEFF Research Database (Denmark)

    Danielsen, Magnus; Jørgensen, Rolf

    1979-01-01

    The principles of using radiating microstrip resonators as elements in a frequency scanning antenna array are described. The resonators are cascade-coupled. This gives a scan of the main lobe due to the phase-shift in the resonator in addition to that created by the transmission line phase......-shift. Experimental results inX-band, in good agreement with the theory, show that it is possible to scan the main lobe an angle ofpm30degby a variation of the frequencypm300MHz, and where the 3 dB beamwidth is less than10deg. The directivity was 14.7 dB, while the gain was 8.1 dB. The efficiency might be improved...

  13. Impact of increasing alanine aminotransferase levels within normal range on incident diabetes

    OpenAIRE

    Chong-Shan Wang; Ting-Tsung Chang; Wei-Jen Yao; Shan-Tair Wang; Pesus Chou

    2012-01-01

    Abnormal alanine aminotransferase level (ALT) levels might be associated with type 2 diabetes, but whether higher ALT levels within the normal range predict the risk is unknown. Methods: We followed a community-based cohort of 3446 individuals who were ≥35 years old without diabetes and hepatitis B or C in southern Taiwan for 8 years (1997–2004) to study the risk for type 2 diabetes with different normal ALT levels. Results: Among the 337 incident diabetes cases, 16.0% were from those w...

  14. A Novel Synthetic Approach to C-Glycosyl-D- and L-Alanines

    Directory of Open Access Journals (Sweden)

    Miroslava Martinková

    2008-12-01

    Full Text Available C-Glycosyl-(S- and (R-alanines 12a and 12b were synthesized from the known β-C-glycoside 1. The nitrogen function was introduced by aza-Claisen rearrangement of the allylic thiocyanate 7, derived from the corresponding alcohol 6. The absolute configuration of the newly created chiral carbon center (C-3 was assigned by X-ray diffraction analysis of the intermediate 3(S-isothiocyanato-D-glycero-D-galacto-decose 8a.

  15. Small-Field Dosimetry in A 6 MV Photon Beam Using Alanine and Liquid Ionisation Chamber

    DEFF Research Database (Denmark)

    Zimmermann, S.; Riis, H. L.; Hjelm-Hansen, M.

    2012-01-01

    Purpose/Objective: Dosimetry of small field sizes in MV photon beams is an increasingly important subject, and a generally accepted guideline for clinical measurements is still lacking. The present comparative study was carried out to further investigate the use of alanine and the PTW microLion...... of each field and depth. This dose maximum was measured for each field using a Scanditronix Wellhöfer photon field diode. The same measurements were carried out using a liquid ionchamber, PTW microLion, irradiated by 500 MU. The output of the accelerator was controlled by a PTW semiflex ion chamber...

  16. Evaluation of alanine as a reference dosimeter for therapy level dose comparisons in megavoltage electron beams

    International Nuclear Information System (INIS)

    McEwen, Malcolm; Sharpe, Peter; Voros, Sandor

    2015-01-01

    When comparing absorbed dose standards from different laboratories (e.g. National Measurement Institutes, NMIs, for Key or Supplementary comparisons) it is rarely possible to carry out a direct comparison of primary standard instruments, and therefore some form of transfer detector is required. Historically, air-filled, unsealed ionization chambers have been used because of the long history of using these instruments, very good stability over many years, and ease of transport. However, the use of ion chambers for therapy-level comparisons is not without its problems. Findings from recent investigations suggest that ion chambers are prone to non-random variations, they are not completely robust to standard courier practices, and failure at any step in a comparison can render all measurements potentially useless. An alternative approach is to identify a transfer system that is insensitive to some of these concerns - effectively a dosimeter that is inexpensive, simple to use, robust, but with sufficient precision and of a size relevant to the disseminated quantity in question. The alanine dosimetry system has been successfully used in a number of situations as an audit dosimeter and therefore the purpose of this investigation was to determine whether alanine could also be used as the transfer detector for dosimetric comparisons, which require a lower value for the measurement uncertainty. A measurement protocol was developed for comparing primary standards of absorbed dose to water in high-energy electron beams using alanine pellets irradiated in a water-equivalent plastic phantom. A trial comparison has been carried out between three NMIs and has indicated that alanine is a suitable alternative to ion chambers, with the system used achieving a precision of 0.1%. Although the focus of the evaluation was on the performance of the dosimeter, the comparison results are encouraging, showing agreement at the level of the combined uncertainties (∼0.6%). Based on this

  17. Inhibition study of alanine aminotransferase enzyme using sequential online capillary electrophoresis analysis.

    Science.gov (United States)

    Liu, Lina; Chen, Yuanfang; Yang, Li

    2014-12-15

    We report the study of several inhibitors on alanine aminotransferase (ALT) enzyme using sequential online capillary electrophoresis (CE) assay. Using metal ions (Na(+) and Mg(2+)) as example inhibitors, we show that evolution of the ALT inhibition reaction can be achieved by automatically and simultaneously monitoring the substrate consumption and product formation as a function of reaction time. The inhibition mechanism and kinetic constants of ALT inhibition with succinic acid and two traditional Chinese medicines were derived from the sequential online CE assay. Our study could provide valuable information about the inhibition reactions of ALT enzyme. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Theoretical investigation of radical species formed from L-α-alanine under gamma-irradiation

    International Nuclear Information System (INIS)

    Simion, C.

    2008-01-01

    Gamma-irradiated L-α-alanine used in EPR-coupled dosimetry has a complex EPR spectrum at room temperature. Changing the temperature or other conditions of the irradiated samples leads to varied EPR spectrum, i.e., some components disappear and/or new ones are formed. We used both molecular mechanics (MM+) and semiempirical (AM1) methods to perform a theoretical investigation of the seven radical species that have been experimentally detected. We established their order of priority in the given simulation conditions (at 0 K, in vacuo). The formation stages advanced for these long-lived radical species were characterized by a theoretical determination of the reaction enthalpies. (author)

  19. Diverse taxa of cyanobacteria produce beta-N-methylamino-L-alanine, a neurotoxic amino acid.

    Science.gov (United States)

    Cox, Paul Alan; Banack, Sandra Anne; Murch, Susan J; Rasmussen, Ulla; Tien, Georgia; Bidigare, Robert Richard; Metcalf, James S; Morrison, Louise F; Codd, Geoffrey A; Bergman, Birgitta

    2005-04-05

    Cyanobacteria can generate molecules hazardous to human health, but production of the known cyanotoxins is taxonomically sporadic. For example, members of a few genera produce hepatotoxic microcystins, whereas production of hepatotoxic nodularins appears to be limited to a single genus. Production of known neurotoxins has also been considered phylogenetically unpredictable. We report here that a single neurotoxin, beta-N-methylamino-L-alanine, may be produced by all known groups of cyanobacteria, including cyanobacterial symbionts and free-living cyanobacteria. The ubiquity of cyanobacteria in terrestrial, as well as freshwater, brackish, and marine environments, suggests a potential for wide-spread human exposure.

  20. Diverse taxa of cyanobacteria produce β-N-methylamino-l-alanine, a neurotoxic amino acid

    Science.gov (United States)

    Cox, Paul Alan; Banack, Sandra Anne; Murch, Susan J.; Rasmussen, Ulla; Tien, Georgia; Bidigare, Robert Richard; Metcalf, James S.; Morrison, Louise F.; Codd, Geoffrey A.; Bergman, Birgitta

    2005-01-01

    Cyanobacteria can generate molecules hazardous to human health, but production of the known cyanotoxins is taxonomically sporadic. For example, members of a few genera produce hepatotoxic microcystins, whereas production of hepatotoxic nodularins appears to be limited to a single genus. Production of known neurotoxins has also been considered phylogenetically unpredictable. We report here that a single neurotoxin, β-N-methylamino-l-alanine, may be produced by all known groups of cyanobacteria, including cyanobacterial symbionts and free-living cyanobacteria. The ubiquity of cyanobacteria in terrestrial, as well as freshwater, brackish, and marine environments, suggests a potential for wide-spread human exposure. PMID:15809446