Academic literature on the topic 'Actinidin'
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Journal articles on the topic "Actinidin"
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Nieuwenhuizen, Niels J., Lesley L. Beuning, Paul W. Sutherland, Neelam N. Sharma, Janine M. Cooney, Lara R. F. Bieleski, Roswitha Schröder, Elspeth A. MacRae, and Ross G. Atkinson. "Identification and characterisation of acidic and novel basic forms of actinidin, the highly abundant cysteine protease from kiwifruit." Functional Plant Biology 34, no. 10 (2007): 946. http://dx.doi.org/10.1071/fp07121.
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Actinidin is a cysteine protease found in Actinidia Lindl. (kiwifruit) species that affects the nutraceutical properties, processing characteristics and allergenicity of the fruit. Given the increased consumption of kiwifruit worldwide and the release of new varieties from different Actinidia species, the expression of actinidin mRNA and protein in a range of kiwifruit tissues was examined. Ten different actinidin mRNAs were identified encoding mature proteins of similar molecular weight (~24 kDa), but with predicted pIs ranging from acidic (pI 3.9) to basic (pI 9.3). In A. deliciosa ‘Hayward’ (green-fleshed kiwifruit) and A. chinensis ‘Hort16A’ and EM4 (gold-fleshed kiwifruit), actinidin mRNAs for acidic and basic proteins were expressed at comparable levels throughout ripening. Actinidin mRNA expression was highest in fruit at harvest, expression decreased as fruit ripened and was much lower in the core compared with outer pericarp tissue. Two-dimensional gel electrophoresis, combined with western analysis and liquid chromatography mass spectrometry (LC-MS) identified low levels of a novel basic actinidin protein in ripe A. deliciosa and A. chinensis fruit. Extremely high levels of an acidic actinidin protein were detected in A. deliciosa fruit and EM4, but this acidic protein appeared to be absent in ‘Hort16A’, the most important commercial cultivar of A. chinensis. Analyses on native gels indicated that both the basic and acidic actinidin isoforms in A. deliciosa were active cysteine proteases. Immunolocalisation showed that actinidin was present in small cells, but not large cells in the outer pericarp of mature A. deliciosa fruit at harvest. Within the small cells, actinidin was localised diffusely in the vacuole, associated with the plasma membrane, and in a layer in the plastids near starch granules. The presence of multiple forms of actinidin and varying protein levels in fruit will impact on the ability to breed new kiwifruit varieties with altered actinidin levels.
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Ali, Maysaa Adil. "Optimizing Extraction Conditions of Actinidin from Kiwifruit (Actinidia deliciosa)." Al-Mustansiriyah Journal of Science 28, no. 3 (July 3, 2018): 61. http://dx.doi.org/10.23851/mjs.v28i3.57.
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Kiwifruit (Actinidia deliciosa) is one many fruits that is rich of enzymes like Actinidin. Actinidin is a member of cysteine protease. In this study, different parameters and conditions were tested for optimal Actinidin extraction from kiwifruit. The tested parameters are optimum buffers, pH, Molarity, time, and amounts (gm) of kiwifruit to volume (ml) of buffer ratio. The best buffer for Actinidin extraction from kiwifruit was Sodium phosphate because it gave high activity, with casein as a substrate. The next experiments used sodium phosphate as an optimal buffer for Actinidin extraction and casein as a substrate, detected the optimal Actinidin extraction conditions were carried out at pH 7.0, 0.1 M of sodium phosphate, 2.5 min of extraction time, 1:0.5 (gm of kiwifruit fruit/ v of sodium phosphate buffer) extraction percentage, and 30 min of incubation time. Also this study showed that the maximum enzyme activity for Actinidin extracted from kiwifruit was at pH 7and at 30 min of incubation with casein as substrate.
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Kiyat, Warsono El. "Potensi Aktinidin sebagai Pelunak Daging." JURNAL AGRI-TEK : Jurnal Penelitian Ilmu-Ilmu Eksakta 20, no. 1 (May 10, 2019): 6–11. http://dx.doi.org/10.33319/agtek.v20i1.44.
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This study aimed to discuss the activity of actinidin in meat tenderization and to understand the ability of actinidin as a substitute for other tenderizing enzymes such as papain. Actinidin could be found in kiwi fruits with a similar structure and proteolytic activity characteristics to papain. The proteolytic activity of actinidin was found to be able to substitute papain in meat tenderizing without creating an off flavor side effect. However, increasing the actinidin concentration could enhance its proteolytic activity. Besides, actinidin also has the ability to hydrolyze collagen proteins and fibrinogens perfectly compared to papain activity.
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Montoya, Carlos A., Shane M. Rutherfurd, Trent D. Olson, Ajitpal S. Purba, Lynley N. Drummond, Mike J. Boland, and Paul J. Moughan. "Actinidin from kiwifruit (Actinidia deliciosacv. Hayward) increases the digestion and rate of gastric emptying of meat proteins in the growing pig." British Journal of Nutrition 111, no. 6 (November 19, 2013): 957–67. http://dx.doi.org/10.1017/s0007114513003401.
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The present study aimed to investigate the effect of dietary actinidin on the kinetics of gastric digestion of beef muscle proteins and on the rate of stomach emptying in growing pigs. For this purpose, 120 pigs (mean body weight 28 (sd2·9) kg) were fed beef muscle protein-based diets containing either actinidin (fresh green kiwifruit pulp or gold kiwifruit pulp supplemented with purified actinidin) or no actinidin (fresh gold kiwifruit pulp or green kiwifruit pulp with inactivated actinidin). Additionally, fifteen pigs were fed with a protein-free diet to determine the endogenous protein flow. Pigs were euthanised at exactly 0·5, 1, 3, 5 and 7 h postprandially (n6 per time point for each kiwifruit diet andn3 for protein-free diet). Stomach chyme was collected for measuring gastric retention, actinidin activity, individual beef muscle protein digestion based on SDS–PAGE and the degree of hydrolysis based on the appearance of free amino groups. The stomach emptying of DM and N was faster when actinidin was present in the diet (P< 0·05): the half gastric emptying time of DM was 137v. 172 min ( ± 7·4 min pooled standard error) for the diets with and without actinidin, respectively. The presence of dietary actinidin in the stomach chyme increased the digestion of beef muscle protein (P< 0·05) and, more specifically, those proteins with a high molecular weight (>34 kDa;P< 0·05). In conclusion, dietary actinidin fed in the form of fresh green kiwifruit increased the rate of gastric emptying and the digestion of several beef muscle proteins.
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REID, James D., Syeed HUSSAIN, Suneal K. SREEDHARAN, Tamara S. F. BAILEY, Surapong PINITGLANG, Emrys W. THOMAS, Chandra S. VERMA, and Keith BROCKLEHURST. "Variation in aspects of cysteine proteinase catalytic mechanism deduced by spectroscopic observation of dithioester intermediates, kinetic analysis and molecular dynamics simulations." Biochemical Journal 357, no. 2 (July 9, 2001): 343–52. http://dx.doi.org/10.1042/bj3570343.
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The possibility of a slow post-acylation conformational change during catalysis by cysteine proteinases was investigated by using a new chromogenic substrate, N-acetyl-Phe-Gly methyl thionoester, four natural variants (papain, caricain, actinidin and ficin), and stopped-flow spectral analysis to monitor the pre-steady state formation of the dithioacylenzyme intermediates and their steady state hydrolysis. The predicted reversibility of acylation was demonstrated kinetically for actinidin and ficin, but not for papain or caricain. This difference between actinidin and papain was investigated by modelling using QUANTA and CHARMM. The weaker binding of hydrophobic substrates, including the new thionoester, by actinidin than by papain may not be due to the well-known difference in their S2-subsites, whereby that of actinidin in the free enzyme is shorter due to the presence of Met211. Molecular dynamics simulation suggests that during substrate binding the sidechain of Met211 moves to allow full access of a Phe sidechain to the S2-subsite. The highly anionic surface of actinidin may contribute to the specificity difference between papain and actinidin. During subsequent molecular dynamics simulations the P1 product, methanol, diffuses rapidly (over < 8ps) out of papain and caricain but ‘lingers’ around the active centre of actinidin. Uniquely in actinidin, an Asp142–Lys145 salt bridge allows formation of a cavity which appears to constrain diffusion of the methanol away from the catalytic site. The cavity then undergoes large scale movements (over 4.8 Å) in a highly correlated manner, thus controlling the motions of the methanol molecule. The changes in this cavity that release the methanol might be those deduced kinetically.
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Praekelt, Uta M., Raymond A. McKee, and Harry Smith. "Molecular analysis of actinidin, the cysteine proteinase of Actinidia chinensis." Plant Molecular Biology 10, no. 3 (1988): 193–202. http://dx.doi.org/10.1007/bf00027396.
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Lindahl, P., M. Abrahamson, and I. Björk. "Interaction of recombinant human cystatin C with the cysteine proteinases papain and actinidin." Biochemical Journal 281, no. 1 (January 1, 1992): 49–55. http://dx.doi.org/10.1042/bj2810049.
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The interaction between recombinant human cystatin C and the cysteine proteinases papain and actinidin was studied by spectroscopic, kinetic and equilibrium methods. The absorption, near-u.v.c.d. and fluorescence-emission difference spectra for the cystatin C-proteinase interactions were all found to be similar to the corresponding spectra for chicken cystatin. The kinetics of binding of cystatin C to the two enzymes were best described by a simple reversible one-step bimolecular mechanism, like the kinetics of the reaction of chicken cystatin with several cysteine proteinases. Moreover, the second-order association rate constants at 25 degrees C, pH 7.4 and I0.15, of 1.1 x 10(7) and 2.4 x 10(6) M-1.s-1 for the reactions of cystatin C with papain and actinidin respectively, were similar to the corresponding rate constants for the chicken inhibitor and close to the value expected for a diffusion-controlled rate. The dissociation equilibrium constants, approx. 11 fM and approx. 19 nM for the binding of cystatin C to papain and actinidin respectively, were also comparable with the dissociation constants for chicken cystatin. The affinity between cystatin C and several inactivated papains or actinidins decreased with increasing size of the inactivating group in a manner similar to that in earlier studies with the chicken inhibitor. Together, these results strongly indicate that the mechanisms of the reactions of cystatin C and chicken cystatin with cysteine proteinases are identical or highly similar, but differ from that of reactions between serine-proteinase inhibitors and their target enzymes. The model for the proteinase-inhibitor interaction, based on the X-ray structure of chicken cystatin, therefore should be largely applicable also to human cystatin C.
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Chalabi, Maryam, Fatemeh Khademi, Reza Yarani, and Ali Mostafaie. "Proteolytic Activities of Kiwifruit Actinidin (Actinidia deliciosa cv. Hayward) on Different Fibrous and Globular Proteins: A Comparative Study of Actinidin with Papain." Applied Biochemistry and Biotechnology 172, no. 8 (March 7, 2014): 4025–37. http://dx.doi.org/10.1007/s12010-014-0812-7.
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Pr�stamo, Guadalupe. "Actinidin in kiwifruit cultivars." Zeitschrift f�r Lebensmittel-Untersuchung und -Forschung 200, no. 1 (January 1995): 64–66. http://dx.doi.org/10.1007/bf01192910.
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Miyazaki-Katamura, Sayaka, Mio Yoneta-Wada, Miyuki Kozuka, Tomohisa Sakaue, Takuya Yamane, Junko Suzuki, Yoshihito Arakawa, and Iwao Ohkubo. "Purification and Biochemical Characterization of Cysteine Protease from Baby Kiwi (Actinidia arguta)." Open Biochemistry Journal 13, no. 1 (August 30, 2019): 54–63. http://dx.doi.org/10.2174/1874091x01913010054.
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Background: It has recently been reported that the fruit, stems and leaves of Actinidia arguta have various potential health effects including an antioxidant effect, anticancer effect, anti-allergic effect and α-glucosidase inhibitory effect. However, little is known about the biochemical properties of cysteine protease in the fruit juice of A. arguta. Methods: Ion exchange chromatography to purify the cysteine protease from the fruit juice of A. arguta, and some synthetic substrates to determinate the enzyme activity were used. Results: Cysteine protease was purified to homogeneity from A. arguta fruit juice by ion exchange chromatography. The molecular weight of the purified enzyme was calculated to be approximately 25,500 by SDS-PAGE in the presence of β-ME. The enzyme rapidly hydrolyzed the substrate Z-Leu-Arg-MCA and moderately hydrolyzed other substrates including Boc-Val-Leu-Lys-MCA, Z-Val-Val-Arg-MCA and Z-Phe-Arg-MCA. Kinetic parameters for these four substrates were determined. The Km, Vmax, Kcat and Kcat/Km values for Z-Leu-Arg-MCA, the most preferentially cleaved by the enzyme, were 100 μM, 63.8 μmoles/mg/min, 27.26 sec-1 and 0.2726 sec-1μM-1, respectively. Furthermore, the activity of the enzyme was strongly inhibited by inhibitors including antipain, leupeptin, E-64, E-64c, kinin-free-LMW kininogen and cystatin C. Those biochemical data indicated that the enzyme was a cysteine protease. The amino acid sequence of the first 21 residues of cysteine protease purified from Actinidia arguta was Val1-Leu-Pro-Asp-Tyr5-Val-Asp-Trp-Arg-Ser10-Ala-Gly-Ala-Val-Val15-Asp-Ile-Lys-Ser-Qln20-Gly. This sequence showed high homology to the sequences of actinidin from Acinidia deliciosa (95.0%) and actinidin from Actinidia eriantha (90%). These three cysteine proteases were thought to be common allied species. Conclusion: The biochemical properties of the enzyme purified from A. arguta fruit juice were determined. These basic data are expected to contribute to the maintenance and improvement of human health as well as to the promotion of protein digestion and absorption through its proteolytic functions.
Dissertations / Theses on the topic "Actinidin"
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Präkelt, Uta M. "Molecular analysis of actinidin." Thesis, University of Leicester, 1987. http://hdl.handle.net/2381/35337.
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Actinidin, the 23.6 kDa cysteine proteinase of Chinese gooseberry (Actinidia chinensis), is present at high concentration in fruits. A fruit-specific cDNA library was established and screened by differential hybridisation and using a synthetic oligonucleotide. Two of ten actinidin clones identified were characterised by sequence analysis. The two very similar cDNAs code for proteins with approximately 90% sequence homology to the published amino acid sequence of actinidin, as well as an additional 25 amino acids following the mature carboxyl terminus. The larger clone in addition has coding potential for 57 residues of an amino-terminal extension with considerable homology to amino-terminal sequences of other cysteine proteinases. From size determinations of both mRNA (1.4 kb) and immunoprecipitated in vitro translation product (39 kDa) it was estimated that actinidin is synthesised as a precursor approximately 15 kDa larger than the mature protein. Features of the prosegment primary sequence are considered with regard to a possible mechanism of inactivation of the proteinase, by analogy with other proteolytic zymogens. The presence of three potential glycosylation sites, one within the carboxy-terminal and two in the amino-terminal extension are consistent with subcellular location of the enzyme within membrane-bound organelles. Results from a Southern blot show that actinidin is encoded by a multigene family of up to ten members. Actinidin gene expression, both at the level of mRNA and protein, is largely restricted to the fruit of A. chinensis, where the level of actinidin mRNA accumulates early during development.
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Yuwono, Triwibowo. "A study of actinidin expression in yeast." Thesis, University of Leicester, 1991. http://hdl.handle.net/2381/34380.
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Four different actinidin gene constructions have been created, each consisting of different functional parts of the actinidin gene: (1) the mature actinidin-coding DNA, (2) the amino-terminal extension, but without the secretion signal, plus the mature actinidin-coding DNA, (3) the mature actinidin plus the carboxy-terminal extension-coding DNA, and (4) the full-length precursor actinidin-coding DNA. The first three constructions were fused to the yeast MFa1 promoter and secretion leader sequence, while the fourth was coupled to the CYC1-GAL UAS promoter. Upon expression in yeast, no protein product was detected in the culture supernatant. Analysis of intracellular proteins showed that actinidin protein was detected only from the actinidin gene constructions which have the carboxy-terminal extensions, suggesting that the carboxy-terminal extension is required for the stability of the protein. Comparison of the actinidin proteins produced in protease-proficient and protease-deficient strains suggests that the processing of the protein requires the activity of vacuolar protease(s) and indicates that the actinidin was translocated into the yeast vacuole. Examination of the amino acid sequence suggested that actinidin possesses potential vacuolar and peroxisomal targeting signals. Since the actinidin precursor was glycosylated it must have entered the secretory pathway before being translocated into a specific cellular compartment. The HSP26 gene promoter has been shown to be induced by heat-shock and upon entry into stationary phase, thus it is potentially useful for heterologous gene expression in yeast.
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Podivinsky, Ellen. "Molecular studies on actinidin, a cysteine protease from kiwifruit." Thesis, University of Auckland, 1991. http://hdl.handle.net/2292/2001.
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Research in this thesis describes the characterisation of mRNA sequences coding for actinidin, a cysteine protease found in abundance in the fruit of kiwifruit (Actinidia deliciosa). The first step in the characterisation required the isolation of mRNA from ripe kiwifruit tissue. The suitability of a number of RNA extraction procedures was investigated. The method finally adopted differed from that used for unripe fruit tissue, and was chosen as a result of the nature of the polysaccharide that contaminated nucleic acids prepared from extracts of kiwifruit fruit tissue. RNA extracted from ripe fruit was used to synthesis a partial cDNA library and clones for actinidin were isolated. A number of these cDNA clones were sequenced; three clones were almost full-length. The actinidin cDNA clones obtained fall into two broad sequence classes. The majority of them encode acidic proteins (pI˜4.7), with 97% homology to the published amino acid sequence of actinidin. The second class encode basic proteins (pI˜8.1), with 83% homology to the published amino acid sequence of actinidin. Both classes of actinidin cDNA sequence encode zymogens, which contain N- and C-terminal extensions not present in the mature form of the enzyme. The N-terminal extension of both sequence classes includes a putative signal peptide. Northern hybridization analysis was used to investigate the tissue specificity of actinidin mRNA expression, and the expression of mRNA for the two actinidin sequence classes during fruit ripening. Both actinidin sequence classes were expressed differentially during the latter stages of kiwifruit fruit development and through post-harvest fruit ripening. The expression of both sequence classes increased from just prior to fruit maturity through ripening and reached a maximum as fruit attained the stage of 'eating' ripeness. The level of expression of the sequences encoding acidic actinidin reached a plateau at this point, while the expression of the sequence encoding basic actinidin appeared to decrease slightly as fruit continued to ripen. The sequences encoding acidic actinidin were expressed during ripening at a much higher level than those encoding basic actinidin. No actinidin mRNA was detected in other tissues except for very low levels of the acidic form in kiwifruit leaf, and low levels of the basic form in senescing petals. A full-length, acidic, actinidin cDNA sequence was introduced into tobacco (Nicotiana tabacum) plants via Agrobacterium tumefaciens-mediated transformation. Using the binary vector pGA643, the sequence was introduced in both the sense and antisense orientation relative to the cauliflower mosaic virus 35S promoter and transgenic plants were obtained for both sequence orientations. The presence of the T-DNA cassette (containing the actinidin sequence) in the plant genomes was determined using PCR analysis, and confirmed by Southern hybridization. A number of the transgenic plants contained multiple insertions of the actinidin sequence, and most plants contained at least one intact copy of the T-DNA cassette. The transcription of the introduced actinidin sequence was investigated by Northern hybridization analysis. All of the plants containing actinidin in the sense orientation, and some of those incorporating the antisense construct, transcribed the actinidin sequence. Attempts to detect actinidin protein in the transgenic plants were unsuccessful. Acidic actinidin was identified as one of the most abundant bands in the total protein profile from ripe kiwifruit fruit tissue. The identity of the protein was confirmed by N-terminal sequence analysis. The electrophoretic mobility of actinidin, both in the total cell homogenate and when partially purified, suggested that the first step in post-translational processing of the zymogen may be the removal of the N-terminal extension. Actinidin was also partially purified and used to raise antibodies. Poor specificity of the antibody for actinidin led to preliminary evidence for the glycosylation of actinidin.
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Gul, Sheraz. "Molecular recognition and electrostatic effects in papain and actinidin cysteine proteinases exhibiting extremes of kinetic behaviour." Thesis, Queen Mary, University of London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265807.
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Fiorentini, Luca <1984>. "Deciphering the Cross-Talk between Actinidia spp. and Pseudomonas Syringae pv. Actinidiae (Psa)." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2016. http://amsdottorato.unibo.it/7528/.
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Pseudomonas syringae pv. actinidiae (Psa) is the causal agent of bacterial canker disease of kiwifruit plants worldwide. The steps of the PhD project followed a logical approach, starting the study of the effect of the interactions first in pure cultures of Pseudomonas syringae pv. actinidiae at different densities, then in more complex systems in which Psa was made interact with synthetic molecules, microbial biocoenosis and the host. Intraspecific communication systems in many bacteria rely on signals synthesis and perception as function of cell density and it is often referred to as “quorum-sensing” (QS). Psa displays three QS-signal receptors, but not the signal synthase gene of N-acyl-homoserine lactones (AHLs). Gene expression by qPCR was analysed at different culture densities in order to evaluate potential effects of the intraspecific communication on pathogenicity. It was established that Psa exploited swarming, swimming and twitching motilities and that the addition of AHLs influenced motility but not the biofilm formation nor virulence in vivo. Analysis of gene expression by qPCR supported in vitro results and revealed that very little resulted density-dependent. It was also evaluated the effect of the bacterial cross-talk considering several microbial species. Those bacteria that share with Psa the same environment on kiwifruit plants primed the gene regulation and the phenotypes such as biofilm production and motility, thus indicating that interspecific signalling may occur and play a crucial role during host colonization. Moreover, Psa phenotypic bioassays and relative gene expression quantitation were characterized in Actinidia spp. plant extracts and xylem saps. In the tested conditions, plant material stimulated biofilm formation, motility and virulence, leading also to high levels of gene expression and disease when inocula grown in plant material was used for infections. Four mutants (psaR1-, psaR3-, algD-, Tr-) were also used to investigate the processes occurring during intraspecific, interspecific and interkingdom communications.
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Henriques, Teresa. "Valorização do kiwi (A. deliciosa) de baixo calibre: extração de actinidina e sua aplicação na produção de hidrolisados de glúten." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/14517.
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Mestrado em Bioquímica - Bioquímica AlimentarO kiwi é o fruto de uma planta pertencente ao género botânico Actinidia, da família das Actinidiaceae. Apesar das suas propriedades bioativas, o desperdício anual associado à venda e processamento do kiwi é bastante significativo. A actinidina é uma cisteína protease que representa 50% da proteína solúvel do kiwi. O objetivo deste trabalho foi valorizar o kiwi e os seus subprodutos estudando o efeito da actinidina no glúten. A enzima foi extraída em quatro condições distintas e os extratos sujeitos a um estudo de cinética enzimática com azocaseína. A extração que resultou num extrato rico em proteína (rendimento superior a 70%) com elevada atividade enzimática específica (1,31 a 14,59 U/mg de proteína) consistiu num simples salting out da proteína presente no sumo do fruto após homogeneização e centrifugação. A zimografia realizada a pH 3, 6 e 8 mostrou ainda que a enzima é ativa numa vasta gama de pH e permitiu identificar diferentes estados de maturação da enzima (N-preactinidina e actinidina madura). Realizaram-se ensaios preliminares para avaliar o efeito da actinidina no glúten através da análise dos hidrolisados de glúten de elevado e baixo peso molecular, obtidos após incubação da enzima com glúten hidratado e com glúten liofilizado. Os hidrolisados foram analisados por FTIR, tendo-se observado alterações estruturais nas amostras tratadas com actinidina. Estas alterações estruturais foram corroboradas pela alteração do perfil eletroforético dos resíduos obtidos após hidrólise e pela presença de aminoácidos livres nos sobrenadantes. A análise dos hidrolisados obtidos por SDS-PAGE após 1, 2 e 24 horas de incubação do glúten liofilizado com actinidina (25, 50 e 75 μg/mg) mostrou a presença de péptidos com baixo peso molecular (entre 30 e 20 kDa). A incubação durante 24 horas resulta numa hidrólise mais extensa, com formação adicional de péptidos com cerca de 20 kDa. Os resultados obtidos permitiram concluir que os extratos de actinidina tem elevado potencial para aplicação industrial na produção de hidrolisados de glúten, com a vantagem de ser uma metodologia de extração simples e de baixo custo.
Kiwifruit is the fruit of a plant belonging to the genus Actinidia, the family of Actinidiaceae. Despite its bioactive properties, the annual waste associated with fruit commercialization and processing is significant. Actinidin is a cysteine protease which represents 50% of the soluble protein in kiwifruit. The goal of this work was to add value to kiwifruit and its by-products through studying actinidin effect in gluten. The enzyme was extracted in four different conditions and extracts subjected to enzyme kinetics study with azocasein. It was found that the extraction resulting in an extract rich in protein (yield greater than 70%) with high specific enzyme activity (1.31 to 14.59 U/mg protein) is obtained through a simple salting out of the protein present in the fruit juice after homogenization and centrifugation. Zymography carried out at pH 3, 6 and 8 also showed that the enzyme is active over a wide pH range and it was possible to identify the mature and N-preactinidin. Preliminary experiments were performed to evaluate the effect of actinidin on gluten by analysis of the high and low molecular weight gluten hydrolysates, obtained after incubation of the enzyme with hydrated and freeze-dried gluten. The hydrolysates were analysed by FTIR, and it was observed structural changes in the samples treated with actinidin. These structural changes were corroborated with the changes observed in the electrophoretic profile of the residues obtained after hydrolysis, and the presence of free amino acids in the supernatants. Analysis of the supernatants obtained by SDS-PAGE after 1, 2 and 24 hours of incubation of the freeze-dried gluten with actinidin (25, 50 and 75 μg/mg) showed the presence of peptides with lower molecular weight (between 30 and 20 kDa). Incubation for 24 hours results in a more extensive hydrolysis with formation of additional peptides about 20 kDa. The results showed that the actinidin extracts has high potential for industrial application in the production of hydrolysed gluten, with the advantage of a simple and low cost extracting methodology.
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Tavares, Débora Fernandes. "Avaliação de bioestimulantes para potenciar o abrolhamento em actinidia (Actinidia deliciosa cv. Hayward)." Master's thesis, ISA-UL, 2016. http://hdl.handle.net/10400.5/12937.
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Mestrado em Engenharia Agronómica - Hortofruticultura e Viticultura - Instituto Superior de Agronomia - ULEm Portugal, a cultura da actinídia está maioritariamente distribuída em zonas com invernos amenos, onde se inclui a região da Bairrada. Contudo, para a cultura abrolhar bem, necessita de pelo menos 600 a 800 horas de frio, que nem sempre ocorrem nesta região. Dada a importância da cultura e o número crescente de novas áreas, torna-se importante o estudo de soluções eficazes para a quebra da dormência. Foi então delineado um ensaio experimental, contemplando um conjunto de produtos existentes no mercado para este fim, nomeadamente o BluPrins® e BluAct (M1), o Kiplant HB15 e Kiplant Inducer (M2), o Siberio e Siberion (M3), o Syncron® e NitroActive® (M4), o W-Uniformity Superplus (M5), o Organihum Plus e Organihum B-Plus (M6) e sem aplicação de produtos (M7). No presente ano, em que se registou apenas 198 horas de frio, nenhum dos produtos contribuiu para uma taxa de abrolhamento (p > 0,05). Relativamente aos restantes parâmetros quantitativos, que culminaram na estimativa da produção, foi novamente a testemunha a destacar-se com os melhores resultados (20 t ha-1) e estatisticamente superior ao da modalidade M2 (10 t ha-1) (p <0,05). O mesmo é justificado pela evolução climatológica anormal do presente ano, que conduziu a uma má decisão da data de aplicação dos produtos. Os produtos uma vez aplicados estimularam o abrolhamento, que foi mais tarde interrompido pelas baixas temperaturas do mês de março e meados de abril, levando possivelmente ao aborto dos primórdios florais que se iam diferenciando nesta fase, sobretudo nas modalidades M1, M2, M3 e M4. Com isto, estas modalidades caracterizaram-se por um abrolhamento heterogéneo, como se pode verificar pelo registo dos estados fenológicos, onde são diferenciadas duas fases distintas na evolução do abrolhamento dos gomos
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Autillo, Matthieu. "Etude du paramagnétisme des actinides en solution." Thesis, Montpellier, 2015. http://www.theses.fr/2015MONTS289.
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Les propriétés physicochimiques des actinides (An) en solution restent difficiles à interpréter et plus particulièrement la différence de comportement entre An(III) et Ln(III). L'étude du comportement paramagnétique des cations actinide peut constituer une méthode « simple » et particulièrement intéressante qui permet de sonder les propriétés électroniques de ces éléments et obtenir des informations sur la nature de l'interaction ligand-actinide. L'objectif de ce travail de thèse est d'appréhender les propriétés paramagnétiques de ces éléments par des mesures de susceptibilité magnétique d'une part et l'étude des déplacements chimiques d'autre part.L'apport d'informations sur les propriétés électroniques des ions actinide pour une variété de degrés d'oxydation (+III, +IV, +V et +VI) a été réalisé par des mesures de susceptibilité magnétique en solution selon la méthode d'Evans. Contrairement aux éléments Ln(III), il n'existe aucun modèle spécifique décrivant clairement les propriétés magnétiques de ces ions en solution. L'acquisition de données de bonnes qualités étant nécessaires, l'influence des dispositifs expérimentaux et de la radioactivité de ces éléments a été analysée. Afin de décrire la structure des états électroniques de faible énergie pour ces cations, les résultats expérimentaux ont été confrontés à des calculs de chimie quantique à partir desquels l'influence du champ des ligands a été étudiée. Ces interprétations ont ensuite été appliquées à la variation des propriétés magnétiques des cations actinide lors de la complexation avec les anions chlorure et nitrate. Les informations sur les liaisons ligand-actinide peuvent être déduites de l'étude directe par RMN des déplacements chimiques de complexes d'actinide. En effet, la présence d'un ion paramagnétique au sein d'un complexe induit des modifications spectrales pouvant être séparées en deux composantes. L'une reliée au degré de covalence des liaisons de coordination et l'autre à la structure tridimensionnelle des complexes en solution. Le problème majeur de ce type d'étude réside dans la difficulté de distinguer les deux contributions. Afin de réaliser une telle étude, nous avons choisi de travailler avec les complexes d'actinide de l'acide dipicolinique (DPA). Dans un premier temps, une étude structurale (par DRX monocristal puis EXAFS) a été menée sur ces complexes formés avec les cations actinide aux degrés d'oxydation +III, +IV, +V et +VI pour caractériser avec précision leurs paramètres structuraux. Ensuite, les différentes méthodes de séparation des deux contributions mettant en jeu la spectroscopie RMN et éprouvées lors de l'étude des complexes de lanthanide (III) ont ensuite été appliquées aux éléments actinide. L'étude des déplacements paramagnétiques associée aux calculs de chimie quantique a permis de caractériser les propriétés magnétiques de ces cations. Contrairement aux études réalisées sur les ions Ln(III), une contribution de contact importante participe au déplacement paramagnétique des complexes d'An(III) et d'An(IV). A l'inverse, pour les cations actinyle, le déplacement paramagnétique des signaux RMN 1H est caractérisé par l'absence de contribution de contact. Cette particularité associée à la géométrie de ces ions a permis de caractériser précisément leurs propriétés magnétiques. Une application de ces résultats à l'étude de complexes formés avec le ligand TEDGA a pu être réalisée. Il apparait de cette étude que les informations obtenues par la description du comportement magnétique des actinides apportent une meilleure compréhension des propriétés physicochimiques de ces ions en solutionThe physiochemical properties of actinide (An) solutions are still difficult to explain, particularly the behavioral differences between An(III) and Ln(III). The study of actinide paramagnetic behavior may be a “simple” method to analyze the electronic properties of actinide elements and to obtain information on the ligand-actinide interaction. The objective of this PhD thesis is to understand the paramagnetic properties of these elements by magnetic susceptibility measurements and chemical shift studies.Studies on actinide electronic properties at various oxidation states in solution were carried out by magnetic susceptibility measurements in solution according to the Evans method. Unlike Ln(III) elements, there is no specific theory describing the magnetic properties of these ions in solution. To obtain accurate data, the influence of experimental measurement technique and radioactivity of these elements was analyzed. Then, to describe the electronic structure of their low-energy states, the experimental results were complemented with quantum chemical calculations from which the influence of the ligand field was studied. Finally, these interpretations were applied to better understand the variations in the magnetic properties of actinide cations in chloride and nitrate media.Information about ligand-actinide interactions may be determined from an NMR chemical shift study of actinide complexes. Indeed, modifications induced by a paramagnetic complex can be separated into two components. The first component, a Fermi contact contribution (δc) is related to the degree of covalency in coordination bonds with the actinide ions and the second, a dipolar contribution (δpc) is related to the structure of the complex. The paramagnetic induced shift can be used only if we can isolate these two terms. To achieve this study on actinide elements, we chose to work with the complexes of dipicolinic acid (DPA).Firstly, to characterize the geometrical parameters, a structural study (by monocrystal XRD and EXAFS) was performed on these complexes with the actinide cations at various oxidation states +III, +IV, +V et +VI. Secondly, various methods for separating the two contributions involving NMR spectroscopy were checked with Ln(III) complexes and applied to actinide elements. The paramagnetic induced shift associated with quantum chemical calculations allowed us to characterize the magnetic properties of these cations. Unlike studies on Ln(III) ions, the An(III) and An(IV) paramagnetic induced shifts suggest a major Fermi contact contribution (δc). On the contrary, for actinyle cations, the paramagnetic induced shifts on 1H NMR signals show no Fermi contact contribution (δc). This characteristic, related to the geometry of these ions, allowed for their magnetic properties to be accurately described. An application of these results to the study of complexes with the TEDGA ligand has been performed.It is apparent from this study that the additional information gained on the description of actinide paramagnetic behavior has led to an improved understanding of the physiochemical properties of these ions in solution
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Dahou, Samir. "Organisation structurale et spectroscopie de peptides susceptibles de complexer des actinides." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20062.
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La contamination des espèces vivantes par les éléments actinides est une source de toxicité radiologique et chimique conduisant à des séquelles graves pour l'organisme contaminé. La plupart des données disponibles sur l'interaction des actinides avec les systèmes biologiques sont basées sur des mesures macroscopiques physiologiques et fournissent très peu d'informations structurales et mécanistiques. Du fait de la complexité des systèmes impliqués dans ces processus, il est difficile de décrire la formation des complexes par des méthodes de biochimie. Notre stratégie a donc été d'approcher cette question par des systèmes biomimétiques très simplifiés que sont les peptides, en étudiant les mécanismes intramoléculaires affectés ou induits par l'interaction cation – ligand. Un pentapeptide carboxylique Ac-DDPDD-NH2 nous a servi de molécule de référence et de point de départ pour évaluer l'influence de la nature du peptide sur la topologie des complexes correspondants. Pour ce faire, différents analogues linéaires (permutations Asp/Ala, peptoïdes) et cycliques ont été synthétisés. De plus, dans le but d'incorporer des fonctions hydroxamates (très affines du Fe(III)) dans le pentapetide de référence, l'étude de la desferrioxamine et de l'acide acetohydroxamique a également été entreprise. Cependant, des difficultés de synthèse ne nous ont pas permis de tester ces dérivés. Trois cations actinides au degré d'oxydation +IV ont été sélectionnés (Th, Np, Pu) et comparés au cation Fe(III) souvent considéré comme analogue biologique du Pu(IV). L'agencement spatial du ligand autour du cation dans les complexes en solution aqueuse tamponnée a été étudié par spectrophotométrie et par Spectroscopie d'Absorption des rayons X. Les données spectroscopiques et l'ajustement des spectres EXAFS nous ont permis de rationaliser la topologie des complexes formés en fonction du peptide considéré : complexes mixtes hydroxy polynucléaires pour les séquences linéaires et cycliques, complexes mononucléaires pour la desferrioxamine. D'autre part, des différences notables sont apparues entre le Fe(III) et les actinides(IV), ce qui traduit une différence de réactivité en solution aqueuseThe contamination of living organisms by actinide elements is at the origin of both radiological and chemical toxicity that may lead to severe dysfunction. Most of the data available on the actinide interaction with biological systems are macroscopic physiological measurements and are lacking a molecular description of the systems. Because of the intricacy of these systems, classical biochemical methods are difficult to implement. Our strategy consisted in designing simplified biomimetic peptides, and describing the corresponding intramolecular interactions with actinides. A carboxylic pentapeptide of the form DDPDD has been at the starting point of this work in order to further assess the influence of the peptide sequence on the topology of the complexes. To do so, various linear (Asp/Ala permutations, peptoïds) and cyclic analogues have been synthesized. Furthermore, in order to include the hydroxamic function (with a high affinity for Fe(III)) in the peptide, both desferrioxamine and acetohydroxamic acid have been investigated. However because of difficulties in synthesis, we have not been able to test these peptides. Three actinide cations have been considered at oxidation state +IV (Th, Np, Pu) and compared to Fe(III), often considered as a biological surrogate of Pu(IV). The spatial arrangement of the peptide around the cation has been probed by spectrophotometry and X-ray Absorption Spectroscopy. The spectroscopic data and EXAFS data adjustment lead us to rationalize the topology of the complexes as a function of the peptide sequence : mix hydroxy polynuclear species for linear and cyclic peptides, mononuclear for the desferrioxamine complexes. Furthermore, significant differences have appeared between Fe(III) and actinide(IV), related to differences of reactivity in aqueous medium
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Deroche, Arnaud. "Réactivité de l’eau à la surface des oxydes d’actinide. Modifications surfaciques et radiolyse." Thesis, Montpellier, 2018. http://www.theses.fr/2018MONTS112/document.
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Les oxydes d’actinides sont des matériaux hygroscopiques. L’adsorption de l’eau à leurs surfaces est susceptible d’entrainer des modifications quant à la nature ou à son état. Dans le cas des oxydes à fort débit de dose, vient s’ajouter les effets de radiolyse de l’eau, entrainant sa décomposition et générant du dihydrogène. Ces deux aspects, étude de surface et radiolyse de l’eau, ont été étudiés ici. L’étude de la génération de dihydrogène par radiolyse de l’eau adsorbée à la surface a montré que cette génération linéaire dans les premiers temps atteint une concentration stable au bout de plusieurs heures. Cet état stationnaire a été très peu observé, et est absent dans le cas d’humidité importante. Un conditionnement dans une atmosphère contenant du dihydrogène a permis de mettre en lumière une réaction de consommation du dihydrogène par le matériau. Ces expériences ont permis de faire émerger un modèle cinétique basé sur deux réactions de production et de consommation de dihydrogène. La première correspond à la décomposition de l’eau sous l’effet du rayonnement, et pour la seconde il est suspecté une réduction partielle de la surface avec la formation d’une phase sous-stœchiométrique en surface. Cependant, aucune technique d’analyse de surface n’a permis de mettre en évidence formellement cette phase. La chromatographie gazeuse inverse est une technique peu intrusive vis-à-vis des couches d’eau adsorbée du fait des températures et des pressions mis en jeux et de l’absence de dépôt d’énergie. Cette technique a été employée sur des oxydes de thorium et d’uranium. Sur oxyde de thorium, il en résulte un impact de la température de calcination, avec un maximum d’énergie de surface pour une calcination à 650°C. Par ailleurs, il a été montré que la préparation du dioxyde de thorium pouvait impacter l’état de sa surface. En effet, il a été observé une déshydratation de l’oxalate de thorium au fil du temps, impactant la structure de ce dernier. Cette modification se répercute sur la surface de l’oxyde final par une chute de l’énergie de surface et par une modification sur la répartition des sites d’adsorption en surface. Néanmoins un traitement chimique de l’oxalate permet de retrouver la réactivité de surface et une distribution des sites d’adsorption. L’hydratation de la surface montre une augmentation de l’énergie de surface, mais cette augmentation n’est observée que pour des hydratations de longues duréesActinide oxides are hygroscopic materials. The adsorption of water on their surfaces is likely to cause changes in the nature or condition. In the case of oxides with a high dose rate, the effects of radiolysis of the water causes the decomposition of water and generates hydrogen. These two aspects: surface study and radiolysis of water have been studied here.The study of the generation of dihydrogen by radiolysis of water adsorbed on the surface has shown that this linear generation in the early stages reaches a stable concentration after several hours. This stationary state has been very little observed, and is absent in the case of significant humidity. Conditioning in a dihydrogen-containing atmosphere made it possible to highlight a reaction of consumption of dihydrogen by the material. These experiments led to the emergence of a kinetic model based on two reactions of production and consumption of dihydrogen. The first corresponds to the decomposition of the water under the effect of the radiation, and for the second it is suspected a partial reduction of the surface with the formation of a sub-stoichiometric phase on the surface, however no technique of analysis of surface has not formally highlighted this phase.Inverse gas chromatography is a technique that is not very intrusive with respect to the adsorbed water layers because of the temperatures and pressures involved and the absence of energy deposition. This technique has been used on oxides of thorium and uranium. On thorium oxide, this results in an impact of the calcination temperature, with a maximum of surface energy for calcination at 650 ° C. In addition, it has been shown that the preparation of thorium dioxide can impact the state of its surface. Indeed, it has been observed dehydration of thorium oxalate over time, impacting the structure of the latter. This modification affects the surface of the final oxide by a drop-in surface energy and a change in the distribution of surface adsorption sites. Nevertheless, a chemical treatment of oxalate makes it possible to recover the surface reactivity and a distribution of the adsorption sites. The hydration of the surface shows an increase in surface energy, but this increase is observed only for hydrations of long duration.Keywords: water sorption, radiolysis, plutonium, inverse gas chromatography, thorium, uranium
Books on the topic "Actinidin"
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Mati͡ukha, V. A. Oksalatnye soedinenii͡a lantanoidov, aktinoidov i nekotorykh perekhodnykh ėlementov. 2nd ed. Moskva: Ėnergoatomizdat, 1991.
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Mati͡ukha, V. A. Oksalatnye soedinenii͡a lantanoidov i aktinoidov. Moskva: Ėnergoatomizdat, 1985.
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Wijn, H. P. J., ed. Actinide Monochalcogenides. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-47043-4.
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Lanthanides and actinides. New York: Oxford University Press, 1991.
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Cotton, Simon. Lanthanides and actinides. London: Macmillan Education UK, 1991. http://dx.doi.org/10.1007/978-1-349-11904-2.
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Brian, Nordstrom, ed. Lanthanides and actinides. New York, NY: Facts on File, 2011.
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Kalmykov, Stepan N., and Melissa A. Denecke. Actinide nanoparticle research. Berlin: Springer, 2010.
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Kalmykov, Stepan N., and Melissa A. Denecke, eds. Actinide Nanoparticle Research. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-11432-8.
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Wijn, H. P. J., ed. Binary Actinide Oxides. Berlin/Heidelberg: Springer-Verlag, 1999. http://dx.doi.org/10.1007/b60166.
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Sterne, P. A., A. Gonis, and A. A. Borovoi, eds. Actinides and the Environment. Dordrecht: Springer Netherlands, 1998. http://dx.doi.org/10.1007/978-94-017-0615-5.
Full textBook chapters on the topic "Actinidin"
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Konings, Rudy J. M., Lester R. Morss, and Jean Fuger. "Thermodynamic Properties of Actinides and Actinide Compounds." In The Chemistry of the Actinide and Transactinide Elements, 2113–224. Dordrecht: Springer Netherlands, 2010. http://dx.doi.org/10.1007/978-94-007-0211-0_19.
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Datson, P. M., and A. R. Ferguson. "Actinidia." In Wild Crop Relatives: Genomic and Breeding Resources, 1–20. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-20447-0_1.
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Lim, T. K. "Actinidia chinensis." In Edible Medicinal and Non-Medicinal Plants, 12–19. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-8661-7_3.
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Lim, T. K. "Actinidia deliciosa." In Edible Medicinal and Non-Medicinal Plants, 20–29. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-8661-7_4.
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Lim, T. K. "Actinidia arguta." In Edible Medicinal and Non-Medicinal Plants, 5–11. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-90-481-8661-7_2.
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Bährle-Rapp, Marina. "Actinidia Chinensis." In Springer Lexikon Kosmetik und Körperpflege, 9. Berlin, Heidelberg: Springer Berlin Heidelberg, 2007. http://dx.doi.org/10.1007/978-3-540-71095-0_176.
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Papaconstantopoulos, Dimitris A. "Actinides." In Handbook of the Band Structure of Elemental Solids, 457–82. Boston, MA: Springer US, 2014. http://dx.doi.org/10.1007/978-1-4419-8264-3_14.
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Reavis, James G. "Actinides." In Molten Salt Techniques, 5–71. Boston, MA: Springer US, 1987. http://dx.doi.org/10.1007/978-1-4613-1847-7_2.
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Sastry, K. Subramanya, Bikash Mandal, John Hammond, S. W. Scott, and R. W. Briddon. "Actinidia chinensis (Kiwifruit)." In Encyclopedia of Plant Viruses and Viroids, 24–30. New Delhi: Springer India, 2019. http://dx.doi.org/10.1007/978-81-322-3912-3_11.
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Ishikawa, Shin-Ichi, Kyozo Suyama, and Isamu Satoh. "Biosorption of Actinides from Dilute Waste Actinide Solution by Egg-Shell Membrane." In Twentieth Symposium on Biotechnology for Fuels and Chemicals, 521–33. Totowa, NJ: Humana Press, 1999. http://dx.doi.org/10.1007/978-1-4612-1604-9_47.
Full textConference papers on the topic "Actinidin"
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Hyland, Bronwyn, and Brian Gihm. "Scenarios for the Transmutation of Actinides in CANDU Reactors." In 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-30123.
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With world stockpiles of used nuclear fuel increasing, the need to address the long-term utilization of this resource is being studied. Many of the transuranic (TRU) actinides in nuclear spent fuel produce decay heat for long durations, resulting in significant nuclear waste management challenges. These actinides can be transmuted to shorter-lived isotopes to reduce the decay heat period or consumed as fuel in a CANDU® reactor. Many of the design features of the CANDU reactor make it uniquely adaptable to actinide transmutation. The small, simple fuel bundle simplifies the fabrication and handling of active fuels. Online refuelling allows precise management of core reactivity and separate insertion of the actinides and fuel bundles into the core. The high neutron economy of the CANDU reactor results in high TRU destruction to fissile-loading ratio. This paper provides a summary of actinide transmutation schemes that have been studied in CANDU reactors at AECL, including the works performed in the past [1–4]. The schemes studied include homogeneous scenarios in which actinides are uniformly distributed in all fuel bundles in the reactor, as well as heterogeneous scenarios in which dedicated channels in the reactor are loaded with actinide targets and the rest of the reactor is loaded with fuel. The transmutation schemes that are presented reflect several different partitioning schemes. Separation of americium, often with curium, from the other actinides enables targeted destruction of americium, which is a main contributor to the decay heat 100 to 1000 years after discharge from the reactor. Another scheme is group-extracted transuranic elements, in which all of the transuranic elements, plutonium (Pu), neptunium (Np), americium (Am), and curium (Cm) are extracted together and then transmuted. This paper also addresses ways of utilizing the recycled uranium, another stream from the separation of spent nuclear fuel, in order to drive the transmutation of other actinides.
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Gerasimov, Aleksander S., Boris R. Bergelson, and Tamara S. Zaritskaya. "Two Periods of Long-Term Storage of Thorium Spent Fuel." In ASME 2001 8th International Conference on Radioactive Waste Management and Environmental Remediation. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/icem2001-1219.
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Abstract Radiotoxicity and decay heat power of actinides from spent thorium-uranium nuclear fuel of VVER-1000 type reactor during 100 000 year storage are discussed. Actinide accumulation in thorium fuel cycle is much less than in uranium fuel cycle. The radiotoxicity of actinides of thorium-uranium fuel by air is 5.5 times less and radiotoxicity by water is 3.5 times less than radiotoxicity of actinides of uranium fuel. Extraction of most important nuclides for transmutation permits to reduce radiologic danger of wastes remaining in storage.
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Dai, Xiongxin, and Sheila Kramer-Tremblay. "Rapid Bioassay Methods for Actinides in Urine." In 18th International Conference on Nuclear Engineering. ASMEDC, 2010. http://dx.doi.org/10.1115/icone18-30252.
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Rapid bioassay methods for the determination of actinides in urine samples at ultra-trace levels are needed for both emergency and routine radiation exposure monitoring. Several rapid actinide urinalysis methods have been recently developed at the AECL Chalk River Laboratories. These methods employ hydrous titanium oxide co-precipitation followed with actinide separation using chromatographic columns; the actinide isotopes are analyzed by alpha spectrometry and inductively coupled plasma mass spectrometry. The chemical recoveries, procedural blanks, and achieved detection limits for these bioassay methods are also presented.
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Stefanovsky, S. V., A. G. Ptashkin, Y. M. Kuliako, S. A. Perevalov, S. V. Yudintsev, A. M. Chekmarev, A. V. Ochkin, and A. M. Chemarev. "Development of Actinide-Containing Waste Immobilization Process." In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4673.
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Actinide wastes involve actinide or rare earth–actinide fractions of high level waste (HLW), Pu-contaminated materials, including incinerator ashes, excess weapons plutonium, and some wastes formed during plutonium conversion in MOX fuel and nuclear accidents. SIA Radon in cooperation with Vernadsky Institute of Geochemistry, Institute of Geology of Ore Deposits, and D. Mendeleev University of Chemical Technology deals with development and testing of actinide waste forms and preparation methods. Zirconolite, pyrochlore, and murataite are considered as host phases for plutonium and other actinides. Two-phase ceramics based on zirconolite-perovskite, pyrochlore-perovskite, perovskite–cubic zirconia-based solid solution, murataite-perovskite, and zirconolite-murataite assemblages were designed for incorporation of actinide and rare earth–actinide fractions of HLW. Glass-ceramics containing apatite-britholite phases have been proposed for incinerator ash fixation. All these matrices have high chemical durability and radiation stability. The most promising method for production of these waste forms is an inductive melting in a cold crucible. Cold pressing and sintering technology is considered as alternative route. Mechanical activation intensifies ceramization process and reduces sintering temperature. Some new methods such as selfsustaining synthesis and plasma melting are being also examined.
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Yu, Haoyang, Bin Liu, Wenxin Zhang, and Jin Cai. "The Effect of MA Transmutation in the PWR on Fuel Cycle." In 2017 25th International Conference on Nuclear Engineering. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/icone25-67787.
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The minor actinides (MA) is important nuclides in the spent fuel which is bad for human ecological environment. Pressurized water reactor (PWR) is the main reactor type at commercial operation around world. It is important to find the appropriate loading patterns when introducing minor actinides to the PWR core. In this paper, we study the effect of MA transmutation in the PWR on fuel cycle. First, we use the MCNP program to simulate the model of PWR and the effective multiplication factor.Then,the MA is introduced into core in different ways and mass to simulate the effective multiplication factor. In conclusion,without considering chemical skim control and control rods, we change the thickness of the MA, until the keff closes to 1, We find that loading minor actinides to burnable poison rods for transmutation is an optimal minor actinide loading pattern.
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Heisbourg, G., N. Dacheux, G. Lagarde, S. Hubert, and J. Ritt. "Kinetic Study of the Crystallized ThO2 and Solid Solutions Th1−xUxO2 Dissolution." In ASME 2001 8th International Conference on Radioactive Waste Management and Environmental Remediation. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/icem2001-1288.
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Abstract Thorium dioxide is an important material for the nuclear industry. In the last decade, there has been a renewal of interest in studying the feasibility of thorium based fuel reactor to decrease the minor actinides production during the burn-up. Furthermore the resistance of the thorium dioxide to aqueous corrosion can make this material attractive for immobilizing tetravalent actinides. Leaching tests of powdered samples of thorium dioxide calcinated at 1300°C showed that the normalized dissolution rate is very low (between 10−6 and 10−7 g/(m2.d) in acidic media, and 10−9–10−10 g/(m2.d) after pH>3 when the formation of colloïdes occurs. Thorium dioxide which is isomorphic with the actinide dioxides such as UO2, PuO2 allows the formation of solid solutions whatever the concentration of the actinide. Several solid solutions Th1−xUxO2 were synthesized with mole-ratios Th/(U+Th) ranging from x = 0 to 1. X-ray powder diffraction data allowed to check that the Vegard’s law is respected in all the range, and specific surface area was also measured. The resistance of the solid-solution to aqueous corrosion was measured as a function of several parameters (leaching time, leachate acidity, uranium concentration) and the kinetics of solid solutions dissolution was determined as a function of the uranium concentration. The stoechiometry of the release of both actinides was verified, however due to the oxidization of U (IV) in U (VI) in contact with the leachate, the dissolution rate of both thorium and uranium increases with the thorium substitution in the solid by uranium (TV).
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Jeanneau, F., M. Gmar, N. Huot, F. Laine´, A. Lyoussi, E. Payan, Ph Pillot, L. Roux, and N. Saurel. "Instrumental Photon Activation and Applications in a Nuclear-Waste Inspection Purpose." In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4765.
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The development of non-destructive methods to inspect nuclear-waste containers is important for radioactive-waste management and non-proliferation purposes. This paper will present studies and results carried out by a method based on photon interrogation (photofission) which allows the determination of the actinide quantity contained in the waste. High-energy photons (produced by an electron accelerator associated with a Bremsstrahlung tungsten target) will induce photofission reactions on the actinides. Then the flux of delayed neutrons, which is directly proportional to the amount of actinides, is measured with 3He detectors. Since the beginning of 1990’s, our team in CEA has been working on the development of this method and the improvement of the existing simulation code. The two main tools will be introduced: OPERA (tool for the simulation of photonuclear reactions) which includes photonuclear cross sections in a Monte-Carlo code based on MCNP4C, and SAPHIR (Irradiation and Photon-Activation System), a device allowing experimentations for research and development programs. The applications of these tools will be illustrated mainly with two examples: 1) The feasibility study of an inspection device for old concrete containers will be reported. Two campaigns of measurements have been performed in order to determine the sensitivity and the detection limits in the case of four different types of concrete containers, in terms of nature and geometry. 2) Nuclear-waste producers and managers have been interested by the active photon interrogation possibilities to measure actinide quantity in wastes of high activity, vitrified or compacted, with constraints like a dose rate around 400 Gy/h at 27 cm from the container. The simulation-code improvement has allowed some calculations, based on the SAPHIR facility, which have shown a good linearity between the actinide mass and the number of detected neutrons, in spite of a very high passive noise and the presence of a lead protection. Several R&D programs will be also presented. On one hand, measurements are performed on real wastes, chosen for parameter which could define a limitation of the measurements, in order to improve the method and to evaluate the detection limits. For instance, tomography can be performed with this experimental device: quantity and position of actinides in the waste can be calculated. On the other hand, a new method is studied, using the delayed-gamma flux in order to quantify and to identify the different actinide isotopes contained in the waste. These methods and device offer a large panel of results in terms of measurements and simulations. Our team is now involved in several prospecting and R&D programs in order to improve the current method and to find some new applications for nuclear-waste management.
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Pokinchereda, A. M., and E. I. Ivanov. "Influence of conditions on rooting of lignified cuttings Actinidia (Actinidia)." In General question of world science. НИЦ «Л-Журнал», 2018. http://dx.doi.org/10.18411/gq-31-03-2018-43.
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Haraga, Tomoko, Yuta Nakano, Masami Shibukawa, Yutaka Kameo, Kuniaki Takahashi, and Shingo Saito. "Capillary Electrophoresis With Laser-Induced Fluorescent Detection Method Using Highly Emissive Probes for Analysis of Actinides in Radioactive Wastes." In ASME 2011 14th International Conference on Environmental Remediation and Radioactive Waste Management. ASMEDC, 2011. http://dx.doi.org/10.1115/icem2011-59092.
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Actinides are important nuclides for the analysis of radioactive wastes arising from nuclear fuel cycle facilities. In order to achieve simple and rapid analysis of actinides, capillary electrophoresis-laser-induced fluorescent detection method (CE-LIF) is one of the potential candidates. In this study, new emissive probes of actinide ions suitable for CE-LIF were developed for the first time. The detection and separation of americium and neptunium ions as model nuclides were examined using several new emissive complexing probes, each of which possessed a fluorophore and a different chelating moiety. With a pre-capillary complexation technique without addition of the probe to separation buffer electrolyte, the highly sensitive fluorescent detection of Am and Np was successfully achieved using acyclic and macrocyclic multidentate probes. The results suggests that the probe with an acyclic hexadentate chelating moiety is suitable for detection and separation of Am and Np. The detection limit of mid–ppt levels was determined.
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Hejzlar, Pavel, Neil E. Todreas, Michael J. Driscoll, Philip E. MacDonald, Jacopo Buongiorno, and Kevan D. Weaver. "Design Strategies for Lead-Alloy-Cooled Reactors for Actinide Burning and Low-Cost Electricity Production." In 10th International Conference on Nuclear Engineering. ASMEDC, 2002. http://dx.doi.org/10.1115/icone10-22377.
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A multi-year project at the INEEL and MIT is investigating the potential of lead or lead-bismuth (lead-alloy) cooled fast critical reactors for producing low-cost electricity as well as for burning actinides from LWR spent fuel. While these two goals are the primary thrust in the development of a conceptual design, the proliferation resistance of the fuel and the plant safety are also important constraints incorporated into the design process. Thus, this concept addresses all Generation IV reactor goals, which involve favorable economics, enhanced safety, and sustainability. This paper outlines the objectives of the project, the challenges shaping the design strategy, and the approaches adopted to achieve the design goals. The most promising path forward is also identified. The four key factors that influence the direction of the design and also require compromise are the actinide destruction rate, safety, economy, and proliferation resistance. Achieving a maximum actinide destruction rate per MWth requires fertile-free fuels. However, the achievement of safe reactivity coefficients in such cores is difficult. If the total elimination of actinides from LWR spent fuel is pursued, multiple reprocessing with high recovery efficiency is necessary. This will probably significantly increase the fuel cycle costs, thus negatively affecting the economics. On the other hand, in-situ breeding and burning of plutonium in cores initially loaded with U235 can be cost effective. However, such a system does not achieve any reduction in the actinide inventory, and the discharge fuel contains relatively pure Pu239, which poses a potential proliferation threat. To reconcile these competing goals, a number of approaches have been investigated to achieve a balanced design that is cost competitive with other alternatives for electricity generation, attains excellent safety, helps in the reduction of transuranics from the spent LWR fuel, and has discharged fuel that is at least as proliferation resistant as spent LWR fuel from a once-through cycle. The preliminary design of the reactor concept that has the best potential to achieve these characteristics is identified and briefly described. This concept incorporates a supercritical carbon dioxide power conversion cycle that achieves thermal efficiencies up to 45% at a core outlet temperature of 550°C. However, conventional steam cycles are also an option.
Reports on the topic "Actinidin"
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Baisden, P., and B. Kadkhodayan. Novel complexing agents for the efficient separation of actinides and remediation of actinide-contaminated sites. Office of Scientific and Technical Information (OSTI), March 1996. http://dx.doi.org/10.2172/226428.
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Haire, R. (Research on actinides). Office of Scientific and Technical Information (OSTI), October 1989. http://dx.doi.org/10.2172/5651717.
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Migliori, Albert. Actinide Research Quarterly. Office of Scientific and Technical Information (OSTI), June 2015. http://dx.doi.org/10.2172/1188164.
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Kersting, Annie B., and Mavrik Zavarin. Subsurface Biogeochemistry of Actinides. Office of Scientific and Technical Information (OSTI), June 2016. http://dx.doi.org/10.2172/1281679.
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Mariella, R. Novel Separation of Actinides. Office of Scientific and Technical Information (OSTI), February 2011. http://dx.doi.org/10.2172/1021063.
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Stoyer, Nancy Jane. Actinide cation-cation complexes. Office of Scientific and Technical Information (OSTI), December 1994. http://dx.doi.org/10.2172/34204.
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Choppin, G. R. Research in actinide chemistry. Office of Scientific and Technical Information (OSTI), January 1993. http://dx.doi.org/10.2172/6735291.
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Browne, Kevin Patrick. Actinide High-Nitrogen Chemistry. Office of Scientific and Technical Information (OSTI), May 2015. http://dx.doi.org/10.2172/1179259.
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Koenig, Z. M., W. D. Ruhter, and R. Gunnink. Actinide isotopic analysis systems. Office of Scientific and Technical Information (OSTI), October 1990. http://dx.doi.org/10.2172/6447881.
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Pietrass, Tanja, David Fredrick Teter, and Karen Elizabeth Kippen. Actinides and Correlated Electron Materials. Office of Scientific and Technical Information (OSTI), March 2018. http://dx.doi.org/10.2172/1425775.
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