Artículos de revistas: "Changes in beta-decay half-life"

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Alves, Naiane Ferraz Bandeira, Suênia Karla Pacheco Porpino y Alexandre Sérgio Silva. "The period between beta-blocker use and physical activity changes training heart rate behavior". Brazilian Journal of Pharmaceutical Sciences 45, n.º 4 (diciembre de 2009): 729–35. http://dx.doi.org/10.1590/s1984-82502009000400017.

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The Brazilian Society of Cardiology (SBC) proposes that hypertensive subjects who use beta-blockers and practice physical exercises must have their training heart rate (HR) corrected due to the negative chronotropic effect of this drug. Nevertheless, if the physical activity is performed outside of plasmatic half-life, correction may not be necessary. This study investigated the exercise chronotropic response both inside and outside the beta-blocker plasmatic half-life. Nine subjects in use of atenolol or propranolol, and six controls, carried out three walking sessions in three days according to different schedules: EX2 (two hours after drug administration, at the plasmatic peak); EX11 (eleven hours after drug administration, at the end of plasmatic half-life); and EX23 (twenty-three hours after drug administration, outside the plasmatic half-life. The walking sessions were performed on an ergometric treadmill and HR was monitored by a heart rate monitor. During the exercises, mean HRs were 97.2, 108.4 and 109 for EX2, EX11 and EX23, respectively, with the value for EX2 statistically lower than the others (p<0.05). There were no statistical differences in the control group (p>0.05). The study concludes that the attenuation of the positive chronotropic response which occurs during exercise in subjects using beta-blockers, is less evident when the exercise is performed outside the plasmatic half-life of the drug.

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2

Naderi, D. y M. Zargooshi. "Study of alpha-decay half-lives with deformed, oriented daughter nuclei". International Journal of Modern Physics E 24, n.º 02 (febrero de 2015): 1550010. http://dx.doi.org/10.1142/s021830131550010x.

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In this paper, Coulomb and proximity potential model has been applied to calculate the half-lives of alpha-decay for isotopes around N = Z = 50. Using this model, we investigated the influence of deformation and orientation of daughter nucleus on alpha-decay half-lives. Two orientations (90° and 180°) with quadrupole deformation are applied to study the role of daughter orientation in alpha-decay process. It is found that the deformation and orientation of daughter nucleus affects the alpha-decay half-life and changes the slope and intercept of linear relation between log10(T1/2) and Q-1/2.

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Wang, Jinjuan y James C. Rose. "Developmental changes in renal renin mRNA half-life and responses to stimulation in fetal lambs". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 277, n.º 4 (1 de octubre de 1999): R1130—R1135. http://dx.doi.org/10.1152/ajpregu.1999.277.4.r1130.

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In the perinatal period there is increased renin gene expression in the kidney compared with other stages of development. This may be related to changes in responsiveness of the renin gene to stimulation and/or differences in renin mRNA stability as development progresses. To ascertain if either responsiveness or stability changes in fetal life, we studied renin mRNA levels in primary cultures of renal cortical cells obtained from fetal lamb kidneys at two stages (0.7 and 0.9) of gestation after stimulation with isoproterenol, forskolin, or isobutyl methylxanthine and after inhibition of transcription with actinomycin D. Forskolin and isobutyl methylxanthine rapidly increased renin mRNA by at least twofold in the cultured cells from fetuses of both ages, with the sensitivity to stimulation higher in the cells from the mature fetal kidneys. Isoproterenol was effective only in mature fetal cells. In addition, the decay of renin mRNA after cessation of transcription was slower in mature cells compared with immature cells, the half-life being 11.6 ± 0.8 h in mature cells and 6.6 ± 0.6 h in immature cells ( P < 0.05). The data suggest that increases in both renin mRNA sensitivity to stimulation and in stability can contribute to the enhanced renin expression in the perinatal period.

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K. P. Anjali, K. Prathapan, R. K. Biju y K. P. Santhosh. "A Systematic Study on the Existence of 7-9B, 16-19Ne, 8-11C, 23-30P and 26-32S Nuclei via Cluster Decay in the Super Heavy Region". Journal of Nuclear Physics, Material Sciences, Radiation and Applications 7, n.º 1 (13 de agosto de 2019): 1–12. http://dx.doi.org/10.15415/jnp.2019.71001.

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Based on the Coulomb and Proximity Potential Model, we have studied the decay probabilities of various exotic nuclei from even-even nuclei in the super heavy region. The half-lives and barrier penetrability for the decay of exotic nuclei such as 7-9B, 16-19 Ne, 8-11 C, 23-30 P and 26-32 S from the isotopes 274-332116,274-334 118 and 288-334120 are determined by considering them as spherical as well as deformed nuclei. The effect of ground state quadrupole (β2), Octupole (β3) and hexadecapole (β4) deformation of parent, daughter and cluster nuclei on half- lives and barrier penetrability were studied. Calculations have done for the spherical nuclei and deformed nuclei in order to present the effects of the deformations on half-lives. It is found that height and shape of the barrier reduces by the inclusion of deformation and hence half-life for the emission of different clusters decreases and barrierpenetrability increases. Changes in the half-lives with and without the inclusion of deformation effects are compared in the graph of half -life and barrier penetrability against neutron number of parents. It is evident from the computed half lives that many of the exotic nuclei emissions are probable. Moreover shell structure effects on the half-lives of decay are evident from these plots. Peak in the plot of halflife and dip in the plot of barrier penetrability against neutron number of parent show shell closure at or near to N=184, N=200 and N=212.

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5

Chambers, SK, M. Gilmore-Hebert, BM Kacinski y EJ Jr Benz. "Changes in Na,K-ATPase gene expression during granulocytic differentiation of HL60 cells". Blood 80, n.º 6 (15 de septiembre de 1992): 1559–64. http://dx.doi.org/10.1182/blood.v80.6.1559.1559.

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Abstract During granulocytic differentiation of HL60 cells, immediate reduction of ouabain-sensitive potassium flux is observed within the first 12 hours of addition of dimethyl sulfoxide (DMSO). We show that gene expression of the alpha 3 isoform of Na+,K(+)-ATPase, which encodes an ouabain-inhibitable Na+,K(+)-ATPase activity, significantly declines during the first 24 hours of granulocytic differentiation by DMSO of HL60 cells. The more common alpha 1 isoform decreases, but more gradually over 72 hours of DMSO induction. Loss of alpha 3 and alpha 1 messenger RNA (mRNA) are due to changes in mRNA decay; their transcription is not altered. alpha 3 mRNA half-life is 3 hours in HL60 cells; upon induction by 16 hours of DMSO, it decreases to approximately 2 hours. alpha 1 transcripts are less sensitive to DMSO induction, with their half-life being 3.5 hours in HL60 cells; upon induction, their half-life decreases to 3 hours. Experiments measuring protein stability confirm that alpha 3 protein is more labile than alpha 1. In uninduced HL60 cells, alpha 3 membrane protein comprises 30% of the total alpha isoforms, and is less stable than alpha 1, with a protein half-life of only 9 hours. Upon DMSO induction, steady-state alpha 3 protein decreases markedly within 10 hours, whereas alpha 1 protein remains stable. These results show that posttranscriptional changes during induction play a major role in the differential regulation of alpha 1 and alpha 3 isoforms of Na+,K(+)-ATPase; regulation of the latter may be important for early granulocytic differentiation, or for one of the differentiated functions of mature granulocytes.

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Chambers, SK, M. Gilmore-Hebert, BM Kacinski y EJ Jr Benz. "Changes in Na,K-ATPase gene expression during granulocytic differentiation of HL60 cells". Blood 80, n.º 6 (15 de septiembre de 1992): 1559–64. http://dx.doi.org/10.1182/blood.v80.6.1559.bloodjournal8061559.

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During granulocytic differentiation of HL60 cells, immediate reduction of ouabain-sensitive potassium flux is observed within the first 12 hours of addition of dimethyl sulfoxide (DMSO). We show that gene expression of the alpha 3 isoform of Na+,K(+)-ATPase, which encodes an ouabain-inhibitable Na+,K(+)-ATPase activity, significantly declines during the first 24 hours of granulocytic differentiation by DMSO of HL60 cells. The more common alpha 1 isoform decreases, but more gradually over 72 hours of DMSO induction. Loss of alpha 3 and alpha 1 messenger RNA (mRNA) are due to changes in mRNA decay; their transcription is not altered. alpha 3 mRNA half-life is 3 hours in HL60 cells; upon induction by 16 hours of DMSO, it decreases to approximately 2 hours. alpha 1 transcripts are less sensitive to DMSO induction, with their half-life being 3.5 hours in HL60 cells; upon induction, their half-life decreases to 3 hours. Experiments measuring protein stability confirm that alpha 3 protein is more labile than alpha 1. In uninduced HL60 cells, alpha 3 membrane protein comprises 30% of the total alpha isoforms, and is less stable than alpha 1, with a protein half-life of only 9 hours. Upon DMSO induction, steady-state alpha 3 protein decreases markedly within 10 hours, whereas alpha 1 protein remains stable. These results show that posttranscriptional changes during induction play a major role in the differential regulation of alpha 1 and alpha 3 isoforms of Na+,K(+)-ATPase; regulation of the latter may be important for early granulocytic differentiation, or for one of the differentiated functions of mature granulocytes.

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7

Roslund, Marja I., Mira Grönroos, Anna-Lea Rantalainen, Ari Jumpponen, Martin Romantschuk, Anirudra Parajuli, Heikki Hyöty, Olli Laitinen y Aki Sinkkonen. "Half-lives of PAHs and temporal microbiota changes in commonly used urban landscaping materials". PeerJ 6 (19 de marzo de 2018): e4508. http://dx.doi.org/10.7717/peerj.4508.

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Background Polycyclic aromatic hydrocarbons (PAHs) accumulate in urban soils, and PAH contamination can change soil microbial community composition. Environmental microbiota is associated with human commensal microbiota, immune system and health. Therefore, studies investigating the degradation of PAHs, and the consequences of soil pollution on microbial communities in urban landscaping materials, are crucial. Methods Four landscaping materials (organic matter 1, 2, 13 and 56%) were contaminated with PAHs commonly found at urban sites (phenanthrene, fluoranthene, pyrene, chrysene and benzo(b)fluoranthene) in PAH concentrations that reflect urban soils in Finland (2.4 µg g -1 soil dry weight). PAHs were analyzed initially and after 2, 4, 8 and 12 weeks by gas chromatography-mass spectrometry. Half-lives of PAHs were determined based on 12-weeks degradation. Bacterial communities were analyzed at 1 and 12 weeks after contamination using Illumina MiSeq 16S rRNA gene metabarcoding. Results Half-lives ranged from 1.5 to 4.4 weeks for PAHs with relatively low molecular weights (phenanthrene, fluoranthene and pyrene) in landscaping materials containing 1–2% organic matter. In contrast, in materials containing 13% and 56% organic matter, the half-lives ranged from 2.5 to 52 weeks. Shorter half-lives of phenanthrene and fluoranthene were thus associated with low organic matter content. The half-life of pyrene was inversely related to the relative abundance of Beta-, Delta- and Gammaproteobacteria, and diversity of Bacteroidetes and Betaprotebacteria. Compounds with higher molecular weights followed compound-specific patterns. Benzo(b)fluoranthene was resistant to degradation and half-life of chrysene was shorter when the relative abundance of Betaproteobacteria was high. Temporal microbiota changes involved increase in the relative abundance of Deltaproteobacteria and decrease in genera Flavobacterium and Rhodanobacter. Exposure to PAHs seems to adjust microbial community composition, particularly within class Beta- and Deltaproteobacteria. Conclusions In this study, PAH degradation depended on the organic matter content and bacterial community composition of landscaping materials. Contamination seems to alter bacterial community composition in landscaping materials depending on material type. This alteration includes changes in bacterial phyla associated with human health and immune system. This may open new possibilities for managing urban environments by careful selection of landscaping materials, to benefit health and wellbeing.

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8

Ehlers, B., J. Czichos y P. Overath. "RNA turnover in Trypanosoma brucei." Molecular and Cellular Biology 7, n.º 3 (marzo de 1987): 1242–49. http://dx.doi.org/10.1128/mcb.7.3.1242.

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Regulation of variant surface glycoprotein (VSG) mRNA turnover in Trypanosoma brucei was studied in bloodstream forms, in procyclic cells, and during in vitro transformation of bloodstream forms to procyclic cells by approach-to-equilibrium labeling and pulse-chase experiments. Upon initiation of transformation at 27 degrees C in the presence of citrate-cis-aconitate, the half-life of VSG mRNA was reduced from 4.5 h in bloodstream forms to 1.2 h in transforming cells. Concomitantly, an approximately 25-fold decrease in the rate of transcription was observed, resulting in a 100-fold reduction in the steady-state level of de novo-synthesized VSG mRNA. This low level of expression was maintained for at least 7 h, finally decreasing to an undetectable level after 24 h. Transcription of the VSG gene in established procyclic cells was undetectable. For comparison, the turnover of polyadenylated and nonpolyadenylated RNA, beta-tubulin mRNA, and mini-exon-derived RNA (medRNA) was studied. For medRNA, no significant changes in the rate of transcription or stability were observed during differentiation. In contrast, while the rate of transcription of beta-tubulin mRNA in in vitro-cultured bloodstream forms, transforming cells, and established procyclic cells was similar, the half life was four to five times longer in procyclic cells (t1/2, 7 h) than in cultured bloodstream forms (t1/2, 1.4 h) or transforming cells (t1/2, 1.7 h). Inhibition of protein synthesis in bloodstream forms at 37 degrees Celsius caused a dramatic 20-fold decrease in the rate of VSG mRNA synthesis and a 6-fold decrease in half-life to 45 min, while beta-tubulin mRNA was stabilized 2- to 3-fold and mRNA stability remained unaffected. It is postulated that triggering transformation or inhibiting protein synthesis induces changes in the abundance of the same regulatory molecules which effect the shutoff of VSG gene transcription in addition to shortening the half-life of VSG mRNA.

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9

Ehlers, B., J. Czichos y P. Overath. "RNA turnover in Trypanosoma brucei". Molecular and Cellular Biology 7, n.º 3 (marzo de 1987): 1242–49. http://dx.doi.org/10.1128/mcb.7.3.1242-1249.1987.

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Regulation of variant surface glycoprotein (VSG) mRNA turnover in Trypanosoma brucei was studied in bloodstream forms, in procyclic cells, and during in vitro transformation of bloodstream forms to procyclic cells by approach-to-equilibrium labeling and pulse-chase experiments. Upon initiation of transformation at 27 degrees C in the presence of citrate-cis-aconitate, the half-life of VSG mRNA was reduced from 4.5 h in bloodstream forms to 1.2 h in transforming cells. Concomitantly, an approximately 25-fold decrease in the rate of transcription was observed, resulting in a 100-fold reduction in the steady-state level of de novo-synthesized VSG mRNA. This low level of expression was maintained for at least 7 h, finally decreasing to an undetectable level after 24 h. Transcription of the VSG gene in established procyclic cells was undetectable. For comparison, the turnover of polyadenylated and nonpolyadenylated RNA, beta-tubulin mRNA, and mini-exon-derived RNA (medRNA) was studied. For medRNA, no significant changes in the rate of transcription or stability were observed during differentiation. In contrast, while the rate of transcription of beta-tubulin mRNA in in vitro-cultured bloodstream forms, transforming cells, and established procyclic cells was similar, the half life was four to five times longer in procyclic cells (t1/2, 7 h) than in cultured bloodstream forms (t1/2, 1.4 h) or transforming cells (t1/2, 1.7 h). Inhibition of protein synthesis in bloodstream forms at 37 degrees Celsius caused a dramatic 20-fold decrease in the rate of VSG mRNA synthesis and a 6-fold decrease in half-life to 45 min, while beta-tubulin mRNA was stabilized 2- to 3-fold and mRNA stability remained unaffected. It is postulated that triggering transformation or inhibiting protein synthesis induces changes in the abundance of the same regulatory molecules which effect the shutoff of VSG gene transcription in addition to shortening the half-life of VSG mRNA.

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10

Bai, Taoping, Yu Chen, Wentao Jiang, Fei Yan y Yubo Fan. "Studies on Foam Decay Trend and Influence of Temperature Jump on Foam Stability in Sclerotherapy". Vascular and Endovascular Surgery 52, n.º 2 (26 de noviembre de 2017): 98–106. http://dx.doi.org/10.1177/1538574417741786.

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Objectives: This study investigated the influence of temperature jump and liquid–gas ratio on foam stability to derive the foam-decay law. Methods: The experimental group conditions were as follows: mutation temperatures (10°C, 16°C, 20°C, 23°C, 25°C, and 27°C to >37°C) and liquid–gas ratios (1:1, 1:2, 1:3, and 1:4). The control group conditions were as follows: temperatures (10°C, 16°C, 20°C, 23°C, 25°C and 27°C) and liquid–gas ratios (1:1, 1:2, 1:3, and 1:4). A homemade device manufactured using the Tessari DSS method was used to prepare the foam. The decay process was videotape recorded. In the drainage rate curve, the temperature rose, and the liquid–gas ratio varied from 1:1 to 1:4, causing faster decay. Results: In the entire process, the foam volume decreased with increasing drainage rate. The relationships were almost linear. Comparison of the experimental and control groups shows that the temperature jump results in a drainage time range of 1 to 15 seconds. The half-life ranges from 10 to 30 seconds. The maximum rate is 18.85%. Changes in the preparation temperature yields a drainage time range of 3 to 30 seconds. The half-life varies from 20 to 60 seconds. Conclusion: Decreasing the temperature jump range and liquid–gas ratio gradually enhances the foam stability. The foam decay time and drainage rate exhibit an exponential function distribution.

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11

Edem, Patricia E., Jesper Fonslet, Andreas Kjær, Matthias Herth y Gregory Severin. "In Vivo Radionuclide Generators for Diagnostics and Therapy". Bioinorganic Chemistry and Applications 2016 (2016): 1–8. http://dx.doi.org/10.1155/2016/6148357.

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In vivo radionuclide generators make complex combinations of physical and chemical properties available for medical diagnostics and therapy. Perhaps the best-known in vivo generator is 212Pb/212Bi, which takes advantage of the extended half-life of 212Pb to execute a targeted delivery of the therapeutic short-lived α-emitter 212Bi. Often, as in the case of 81Rb/81Kr, chemical changes resulting from the transmutation of the parent are relied upon for diagnostic value. In other instances such as with extended alpha decay chains, chemical changes may lead to unwanted consequences. This article reviews some common and not-so-common in vivo generators with the purpose of understanding their value in medicine and medical research. This is currently relevant in light of a recent push for alpha emitters in targeted therapies, which often come with extended decay chains.

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Pandrea, Ivona, Ruy M. Ribeiro, Rajeev Gautam, Thaidra Gaufin, Melissa Pattison, Mary Barnes, Christopher Monjure et al. "Simian Immunodeficiency Virus SIVagm Dynamics in African Green Monkeys". Journal of Virology 82, n.º 7 (23 de enero de 2008): 3713–24. http://dx.doi.org/10.1128/jvi.02402-07.

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ABSTRACT The mechanisms underlying the lack of disease progression in natural simian immunodeficiency virus (SIV) hosts are still poorly understood. To test the hypothesis that SIV-infected African green monkeys (AGMs) avoid AIDS due to virus replication occurring in long-lived infected cells, we infected six animals with SIVagm and treated them with potent antiretroviral therapy [ART; 9-R-(2-phosphonomethoxypropyl) adenine (tenofovir) and beta-2,3-dideoxy-3-thia-5-fluorocytidine (emtricitabine)]. All AGMs showed a rapid decay of plasma viremia that became undetectable 36 h after ART initiation. A significant decrease of viral load was observed in peripheral blood mononuclear cells and intestine. Mathematical modeling of viremia decay post-ART indicates a half-life of productively infected cells ranging from 4 to 9.5 h, i.e., faster than previously reported for human immunodeficiency virus and SIV. ART induced a slight but significant increase in peripheral CD4+ T-cell counts but no significant changes in CD4+ T-cell levels in lymph nodes and intestine. Similarly, ART did not significantly change the levels of cell proliferation, activation, and apoptosis, already low in AGMs chronically infected with SIVagm. Collectively, these results indicate that, in SIVagm-infected AGMs, the bulk of virus replication is sustained by short-lived cells; therefore, differences in disease outcome between SIVmac infection of macaques and SIVagm infection of AGMs are unlikely due to intrinsic differences in the in vivo cytopathicities between the two viruses.

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Ross, J. y TD Sullivan. "Half-lives of beta and gamma globin messenger RNAs and of protein synthetic capacity in cultured human reticulocytes". Blood 66, n.º 5 (1 de noviembre de 1985): 1149–54. http://dx.doi.org/10.1182/blood.v66.5.1149.1149.

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Abstract The turnover rates of beta and gamma globin messenger RNAs and of beta and gamma globin protein synthesis in human reticulocytes have been measured. Our goal was to determine whether beta globin mRNA is significantly more stable than gamma globin mRNA during the final stages of erythroid cell maturation. Such a result could explain the reported increase in the beta-gamma protein synthetic ratio during erythroid maturation. As determined by molecular hybridization and cell- free translation assays, the half-lives of both mRNAs are 20 to 29 hours in adult and neonatal reticulocytes. Protein synthetic capacity in intact cells decays with a half-life of six to eight hours, but beta protein synthesis declines at the same rate as gamma. Therefore, the changing ratio of fetal to adult hemoglobin synthesis during late erythroid maturation does not result from differences in mRNA turnover rates or changes in translation efficiencies. These data, coupled with those obtained with immature erythroid cells (Farquhar et al, Dev Biol 85: 403, 1981), suggest that, during erythroid maturation, the gamma- beta globin protein synthesis ratio declines because gamma gene transcription ceases earlier than beta gene transcription. Our results also indicate that the protein synthetic machinery, not the quantity of mRNA, becomes rate-limiting for globin production in cultured reticulocytes.

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Ross, J. y TD Sullivan. "Half-lives of beta and gamma globin messenger RNAs and of protein synthetic capacity in cultured human reticulocytes". Blood 66, n.º 5 (1 de noviembre de 1985): 1149–54. http://dx.doi.org/10.1182/blood.v66.5.1149.bloodjournal6651149.

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The turnover rates of beta and gamma globin messenger RNAs and of beta and gamma globin protein synthesis in human reticulocytes have been measured. Our goal was to determine whether beta globin mRNA is significantly more stable than gamma globin mRNA during the final stages of erythroid cell maturation. Such a result could explain the reported increase in the beta-gamma protein synthetic ratio during erythroid maturation. As determined by molecular hybridization and cell- free translation assays, the half-lives of both mRNAs are 20 to 29 hours in adult and neonatal reticulocytes. Protein synthetic capacity in intact cells decays with a half-life of six to eight hours, but beta protein synthesis declines at the same rate as gamma. Therefore, the changing ratio of fetal to adult hemoglobin synthesis during late erythroid maturation does not result from differences in mRNA turnover rates or changes in translation efficiencies. These data, coupled with those obtained with immature erythroid cells (Farquhar et al, Dev Biol 85: 403, 1981), suggest that, during erythroid maturation, the gamma- beta globin protein synthesis ratio declines because gamma gene transcription ceases earlier than beta gene transcription. Our results also indicate that the protein synthetic machinery, not the quantity of mRNA, becomes rate-limiting for globin production in cultured reticulocytes.

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Ogg, G. S., X. Jin, S. Bonhoeffer, P. Moss, M. A. Nowak, S. Monard, J. P. Segal et al. "Decay Kinetics of Human Immunodeficiency Virus-Specific Effector Cytotoxic T Lymphocytes after Combination Antiretroviral Therapy". Journal of Virology 73, n.º 1 (1 de enero de 1999): 797–800. http://dx.doi.org/10.1128/jvi.73.1.797-800.1999.

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ABSTRACT Little is known of the changes in human immunodeficiency virus type 1 (HIV-1)-specific effector cytotoxic T lymphocytes (CTL) after potent antiretroviral therapy. Using HLA/peptide tetrameric complexes, we show that after starting treatment, there are early rapid fluctuations in the HIV-1-specific CTL response which last 1 to 2 weeks. These fluctuations are followed by an exponential decay (median half-life, 45 days) of HIV-1-specific CTL which continues while viremia remains undetectable. These data have implications for the immunological control of drug-resistant virus.

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Nakanishi, S. T. y P. J. Whelan. "Diversification of Intrinsic Motoneuron Electrical Properties During Normal Development and Botulinum Toxin–Induced Muscle Paralysis in Early Postnatal Mice". Journal of Neurophysiology 103, n.º 5 (mayo de 2010): 2833–45. http://dx.doi.org/10.1152/jn.00022.2010.

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During early postnatal development, between birth and postnatal days 8–11, mice start to achieve weight-bearing locomotion. In association with the progression of weight-bearing locomotion there are presumed developmental changes in the intrinsic electrical properties of spinal α-motoneurons. However, these developmental changes in the properties of α-motoneuron properties have not been systematically explored in mice. Here, data are presented documenting the developmental changes of selected intrinsic motoneuron electrical properties, including statistically significant changes in action potential half-width, intrinsic excitability and diversity (quantified as coefficient of variation) of rheobase current, afterhyperpolarization half-decay time, and input resistance. In various adult mammalian preparations, the maintenance of intrinsic motoneuron electrical properties is dependent on activity and/or transmission-sensitive motoneuron–muscle interactions. In this study, we show that botulinum toxin–induced muscle paralysis led to statistically significant changes in the normal development of intrinsic motoneuron electrical properties in the postnatal mouse. This suggests that muscle activity during early neonatal life contributes to the development of normal motoneuron electrical properties.

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Moser, G. H., J. Schrader y A. Deussen. "Turnover of adenosine in plasma of human and dog blood". American Journal of Physiology-Cell Physiology 256, n.º 4 (1 de abril de 1989): C799—C806. http://dx.doi.org/10.1152/ajpcell.1989.256.4.c799.

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To determine half-life and turnover of plasma adenosine, heparinized blood from healthy volunteers was incubated with radiolabeled adenosine in the physiological concentration range of 0.1-1 microM. Plasma levels of adenosine in vitro were 82 +/- 14 nM and were similar to those determined immediately after blood collection with a "stopping solution." Dipyridamole (83 microM) and erythro-9(2-hydroxynon-3yl)-adenine (EHNA) (8 microM) did not measurably alter basal adenosine levels but completely blocked the uptake of added adenosine. Inhibition of ecto-5'-nucleotidase with 100 microM alpha, beta-methyleneadenosine 5'-diphosphate (AOPCP) reduced plasma adenosine to 22 +/- 6 nM. For the determination of adenosine turnover, the decrease in specific radioactivity of added [3H]adenosine was measured using a dipyridamole-containing stopping solution. Without altering basal adenosine levels, the half-life was estimated to be 0.6 s. Similar experiments were carried out with washed erythrocytes or in the presence of AOPCP, yielding half-lives of 0.7 and 0.9 s, respectively. When the initial adenosine concentration was 1 microM, its specific activity decreased by only 11% within 5 s, whereas total plasma adenosine exponentially decreased with a half-life of 1.5 s. Venous plasma concentrations were measured after relief of a 3-min forearm ischemia. Changes in plasma adenosine did not correlate well with changes in blood flow but were augmented in the presence of dipyridamole.(ABSTRACT TRUNCATED AT 250 WORDS)

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Hablitz, J. J. y R. H. Thalmann. "Conductance changes underlying a late synaptic hyperpolarization in hippocampal CA3 neurons". Journal of Neurophysiology 58, n.º 1 (1 de julio de 1987): 160–79. http://dx.doi.org/10.1152/jn.1987.58.1.160.

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1. Single-electrode current- and voltage-clamp techniques were employed to study properties of the conductance underlying an orthodromically evoked late synaptic hyperpolarization or late inhibitory postsynaptic potential (IPSP) in CA3 pyramidal neurons in the rat hippocampal slice preparation. 2. Late IPSPs could occur without preceding excitatory postsynaptic potentials at the resting membrane potential and were graded according to the strength of the orthodromic stimulus. The membrane hyperpolarization associated with the late IPSP peaked within 140-200 ms after orthodromic stimulation of mossy fiber afferents. The late IPSP returned to base line with a half-decay time of approximately 200 ms. 3. As determined from constant-amplitude hyperpolarizing-current pulses, the membrane conductance increase during the late IPSP, and the time course of its decay, were similar whether measurements were made near the resting membrane potential or when the cell was hyperpolarized by approximately 35 mV. 4. When 1 mM cesium was added to the extracellular medium to reduce inward rectification, late IPSPs could be examined over a range of membrane potentials from -60 to -140 mV. For any given neuron, the late IPSP amplitude-membrane potential relationship was linear over the same range of membrane potentials for which the slope input resistance was constant. The late IPSP reversed symmetrically near -95 mV. 5. Intracellular injection of ethyleneglycol-bis-(beta-aminoethylether)-N,N'-tetraacetic acid or extracellular application of forskolin, procedures known to reduce or block certain calcium-dependent potassium conductances in CA3 neurons, had no significant effect on the late IPSP. 6. Single-electrode voltage-clamp techniques were used to analyze the time course and voltage sensitivity of the current underlying the late IPSP. This current [the late inhibitory postsynaptic current (IPSC)] began as early as 25 ms after orthodromic stimulation and reached a peak 120-150 ms following stimulation. 7. The late IPSC decayed with a single exponential time course (tau = 185 ms). 8. A clear reversal of the late IPSC at approximately -99 mV was observed in a physiological concentration of extracellular potassium (3.5 mM).(ABSTRACT TRUNCATED AT 400 WORDS)

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Bai, Hao, Yu-Gao Zhang, Nong Zhang, De-Sheng Kong, Hong-Shen Guo, Wei Mo, Qi-Qun Tang, Hou-Yan Song y Duan Ma. "Molecular design and characterization of recombinant long half-life mutants of human tissue factor pathway inhibitor". Thrombosis and Haemostasis 93, n.º 06 (2005): 1055–60. http://dx.doi.org/10.1160/th04-11-0721.

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SummaryTissue factor pathway inhibitor (TFPI) is a physiological inhibitor of extrinsic pathway of coagulation and has biological functions of anticoagulation and anti-inflammation. Although TFPI has been proved to be a good therapeutic agent of sepsis, inflammatory shock, and DIC, the clinical application and therapeutic effects of TFPI are impeded because of its short half-life in vivo. In order to prolong the half-life of TFPI, homology modeling and molecule docking were performed on a computer workstation principally in protein structural biology and binding characteristics between TFPI and its receptor LRP (low-density lipoprotein receptor related protein). Two recombinant long half-life human TFPI mutants coined TFPI-Mut1 and TFPI-Mut4 were designed and expressed in E.coli. In comparison with the wild-type TFPI, TFPI-Mut1 and TFPI-Mut4 presented a few of changes in spatial configuration and a decrease in relative Gibbs free energy of docking complex by 17.3% and 21.5%, respectively, as indicated by a computer simulation. After refolding and purification, anticoagulant activities, anti-TF/FVIIa and anti-FXa activities of the mutants were found to be the same as those of wide-type TFPI. The pharmacokinetics research indicated that alpha phase half-life (t1/2α) of TFPI-Mut1 and TFPI-Mut4 were prolonged 1.33-fold and 1.96-fold respectively, beta phase half-life (t1/2 β) of TFPI-Mut1 and TFPI-Mut4 were prolonged 1.62-fold and 4.22-fold respectively. These results suggested that TFPI-Mut1 and TFPI-Mut4 maintained the bioactivities of wild-type TFPI, prolonged half-life in vivo simultaneously and were expected for better clinical value and therapeutic effect.

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20

Tong, Z., G. R. Pitts, D. N. Foster y M. E. El Halawani. "Transcriptional and post-transcriptional regulation of prolactin during the turkey reproductive cycle". Journal of Molecular Endocrinology 18, n.º 3 (junio de 1997): 223–31. http://dx.doi.org/10.1677/jme.0.0180223.

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ABSTRACT The present study examined turkey prolactin (PRL) transcription and PRL mRNA stability during different reproductive stages. Nuclear run-on transcription assays were performed using isolated nuclei from pituitaries of turkeys at different reproductive stages. Meanwhile, cytoplasmic PRL mRNA and plasma PRL were measured by slot blot and RIA respectively. The PRL transcription, pituitary cytoplasmic PRL mRNA abundance and plasma PRL levels increased after photostimulation and peaked at the incubating stage (P<0·05). A decrease in PRL transcription, pituitary cytoplasmic PRL mRNA and plasma PRL (P<0·05) was observed during the transition from incubation to photorefractoriness. Nest-deprivation reduced circulating PRL (P<0·05), whereas pituitary cytoplasmic PRL mRNA and PRL transcription were not significantly altered from those in incubating birds (P>0·05). The half-life of PRL mRNA was determined in pituitaries of non-photostimulated, laying, incubating and photorefractory hens. Primary pituitary cell cultures were treated with the transcription inhibitor actinomycin-D and the decay of the pre-existing PRL mRNA was quantified using Northern blot analysis. The PRL mRNA half-life was 1·5- and 1·4-fold greater in incubating and laying birds respectively than in non-photostimulated turkeys (P<0·05). The half-life of PRL mRNA in photorefractory and incubating hens was similar in spite of great differences in pituitary PRL mRNA steady-state levels and PRL transcription. Our data suggest that photoinduced changes in pituitary PRL mRNA and plasma PRL are due to changes in both PRL transcription and PRL mRNA stability. Nest-deprivation inhibits the PRL releasing mechanism(s) independently of PRL transcription in turkeys.

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21

Vakalopoulou, E., J. Schaack y T. Shenk. "A 32-kilodalton protein binds to AU-rich domains in the 3' untranslated regions of rapidly degraded mRNAs." Molecular and Cellular Biology 11, n.º 6 (junio de 1991): 3355–64. http://dx.doi.org/10.1128/mcb.11.6.3355.

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An AU-rich sequence present within the 3' untranslated region has been shown to mark some short-lived mRNAs for rapid degradation. We demonstrate by label transfer and gel shift experiments that a 32-kDa polypeptide, present in nuclear extracts, specifically interacts with the AU-rich domains present within the 3' untranslated region of human granulocyte-macrophage colony-stimulating factor, c-fos, and c-myc mRNAs and a similar domain downstream of the poly(A) addition site of the adenovirus IVa2 mRNA. Competition experiments and partial protease analysis indicated that the same polypeptide interacts with all four RNAs. A single AUUUA sequence in a U-rich context was sufficient to signal binding of the 32-kDa polypeptide. Insertion of three copies of this minimal recognition site led to markedly reduced accumulation of beta-globin RNA, while the same insert carrying a series of U-to-G changes had little effect on RNA levels. Steady-state levels of beta-globin-specific nuclear RNA, including incompletely processed RNA, and cytoplasmic mRNA were reduced. Cytoplasmic mRNA containing the AU-rich recognition sites for the 32-kDa polypeptide exhibited a half-life shorter than that of mRNA with a mutated insert. We suggest that binding of the 32-kDa polypeptide may be involved in the regulation of mRNA half-life.

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22

Vakalopoulou, E., J. Schaack y T. Shenk. "A 32-kilodalton protein binds to AU-rich domains in the 3' untranslated regions of rapidly degraded mRNAs". Molecular and Cellular Biology 11, n.º 6 (junio de 1991): 3355–64. http://dx.doi.org/10.1128/mcb.11.6.3355-3364.1991.

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An AU-rich sequence present within the 3' untranslated region has been shown to mark some short-lived mRNAs for rapid degradation. We demonstrate by label transfer and gel shift experiments that a 32-kDa polypeptide, present in nuclear extracts, specifically interacts with the AU-rich domains present within the 3' untranslated region of human granulocyte-macrophage colony-stimulating factor, c-fos, and c-myc mRNAs and a similar domain downstream of the poly(A) addition site of the adenovirus IVa2 mRNA. Competition experiments and partial protease analysis indicated that the same polypeptide interacts with all four RNAs. A single AUUUA sequence in a U-rich context was sufficient to signal binding of the 32-kDa polypeptide. Insertion of three copies of this minimal recognition site led to markedly reduced accumulation of beta-globin RNA, while the same insert carrying a series of U-to-G changes had little effect on RNA levels. Steady-state levels of beta-globin-specific nuclear RNA, including incompletely processed RNA, and cytoplasmic mRNA were reduced. Cytoplasmic mRNA containing the AU-rich recognition sites for the 32-kDa polypeptide exhibited a half-life shorter than that of mRNA with a mutated insert. We suggest that binding of the 32-kDa polypeptide may be involved in the regulation of mRNA half-life.

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23

Borge, M. J. G., R. Boutami, L. M. Fraile, K. Gulda, W. Kurcewicz, H. Mach, T. Martínez, B. Rubio y O. Tengblad. "Beta decay half-life of 231Ra". Physica Scripta T125 (28 de junio de 2006): 180–81. http://dx.doi.org/10.1088/0031-8949/2006/t125/040.

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24

Du, Bin, Haibo Bai y Guangming Wu. "Dynamic Compression Properties and Deterioration of Red-Sandstone Subject to Cyclic Wet-Dry Treatment". Advances in Civil Engineering 2019 (23 de enero de 2019): 1–10. http://dx.doi.org/10.1155/2019/1487156.

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Rock engineering is usually associated with impact loads induced by blasting, drilling, vibration, or earthquake. In the engineering fields of tunnelling, slopes, dams, and mining, rocks are always subjected to cyclic wet-dry caused by periodical variation in moisture. To study cyclic wet-dry effects on dynamic compression properties and deterioration of red-sandstone, physical tests and dynamic and static tests were conducted after 0, 5, 10, 15, and 20 wet-dry cycles. Changes in physical and mechanical parameters, including P-wave velocity, density, and static and dynamic compression strength, were determined. Deterioration of red-sandstone caused by wet-dry cycles was verified through physicomechanical parameters, and the microscopic features were scanned by SEM techniques. Experimental results showed that the dynamic compression strength increased with the loading rate, but decreased with the increase of wet-dry cycles. In terms of the loading rate, the decay function model was proposed to evaluate the long-term dynamic compression strength of red-sandstone against cyclic wet-dry action. Besides, the function of the loading rate was obtained. Parameters of two models, decay constant and half-life values, were measured accurately.

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25

Beggs, Clive B. y Eldad J. Avital. "A psychrometric model to assess the biological decay of the SARS-CoV-2 virus in aerosols". PeerJ 9 (2 de marzo de 2021): e11024. http://dx.doi.org/10.7717/peerj.11024.

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There is increasing evidence that the 2020 COVID-19 pandemic has been influenced by variations in air temperature and humidity. However, the impact that these environmental parameters have on survival of the SARS-CoV-2 virus has not been fully characterised. Therefore, an analytical study was undertaken using published data to develop a psychrometric model to assess the biological decay rate of the virus in aerosols. This revealed that it is possible to describe with reasonable accuracy (R2 = 0.718, p < 0.001) the biological decay constant for the SARS-CoV-2 virus using a regression model with enthalpy, vapour pressure and specific volume as predictors. Applying this to historical meteorological data from London, Paris and Milan over the pandemic period, produced results which indicate that the average half-life of the virus in aerosols outdoors was in the region 13–22 times longer in March 2020, when the outbreak was accelerating, than it was in August 2020 when epidemic in Europe was at its nadir. However, indoors, this variation is likely to be much less. As such, this suggests that changes in virus survivability due the variations in the psychrometric qualities of the air might influence the transmission of SARS-CoV-2.

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26

Bigler, Christof y Thomas T. Veblen. "Changes in litter and dead wood loads following tree death beneath subalpine conifer species in northern Colorado". Canadian Journal of Forest Research 41, n.º 2 (febrero de 2011): 331–40. http://dx.doi.org/10.1139/x10-217.

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Litter and dead wood affect important processes in forest ecosystems such as nutrient and carbon cycling and are key influences on biodiversity and fire behavior. Increased tree mortality rates in western North America associated with climate trends and increased bark beetle activity highlight the need to better understand the dynamics of litter and dead wood following tree death. For eight old-growth stands in a subalpine forest landscape in northern Colorado (USA), we compared litter and dead wood loads beneath more than 200 dead and live Engelmann spruce (Picea engelmannii Parry ex Engelm.), subalpine fir (Abies lasiocarpa (Hook.) Nutt.), and lodgepole pine (Pinus contorta Douglas ex Loudon). The dynamics of litter and dead wood were analyzed using chronosequences of tree death dates over >100 years that we determined from tree rings. Immediately following tree death, high loads of litter accumulated, particularly for the biggest spruces, which accumulated 10 times more litter than live spruces (five times more for fir, two times more for pine). We estimated a higher decay rate of litter for spruce (half-life of four years) than for pine (15 years) and fir (19 years). The accumulation rates for dead wood following tree death were highly variable among trees, but maximum accumulation was attained during the first 50–60 years.

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27

Selby, Nicholas M., Sally A. Fonseca, Richard J. Fluck y Maarten W. Taal. "Hemoglobin Variability with Epoetin Beta and Continuous Erythropoietin Receptor Activator in Patients on Peritoneal Dialysis". Peritoneal Dialysis International: Journal of the International Society for Peritoneal Dialysis 32, n.º 2 (marzo de 2012): 177–82. http://dx.doi.org/10.3747/pdi.2010.00299.

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♦ Background and Objectives The extent to which hemoglobin (Hb) cycling occurs in peritoneal dialysis (PD) patients is unclear. It is also uncertain whether different types of erythropoiesis-stimulating agents (ESAs) affect such cycling. We performed a retrospective cohort study of our PD population before and after the entire program was switched from epoetin beta (NeoRecormon: Hoffman–LaRoche, Basel, Switzerland) to continuous erythropoietin receptor activator [CERA (Mircera: Hoffman–LaRoche)]. ♦ Design, Setting, Participants, and Measurements The study included 79 patients receiving PD for end-stage renal failure and being treated with an ESA. Hemoglobin concentrations were measured monthly, and each study period ran for 12 months. Patient demographics and details of intercurrent illness and hospital admission were collected. ♦Results There was a trend to fewer patients on CERA (26 patients, 68.4%) than on epoetin beta (36 patients, 87.8%, p = 0.054) experiencing Hb excursions. The CERA group also required fewer dose changes. However, there was no difference in the proportion of patients experiencing complete Hb cycles. On logistic regression, the factors associated with Hb cycling were ESA dose increase or decrease and hospital admission. We also observed a positive correlation between the delta ESA dose and the amplitude of Hb excursion, suggesting that the dose changes were causal, rather than reactive. ♦Conclusions Hemoglobin cycling occurs in PD patients and is largely a consequence of current practice in ESA dosing, plus the effects of intercurrent illness. The longer half life of CERA may offer a small advantage in reducing the degree of Hb variability, possibly because of fewer dose changes per patient.

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28

Heiskanen, H., M. T. Mustonen y J. Suhonen. "Theoretical half-life for beta decay of96Zr". Journal of Physics G: Nuclear and Particle Physics 34, n.º 5 (30 de marzo de 2007): 837–43. http://dx.doi.org/10.1088/0954-3899/34/5/005.

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29

Marti, K. y S. V. S. Murty. "Double beta-decay half-life of 82Se". Physics Letters B 163, n.º 1-4 (noviembre de 1985): 71–74. http://dx.doi.org/10.1016/0370-2693(85)90194-7.

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30

Cheng, J. y L. E. Maquat. "Nonsense codons can reduce the abundance of nuclear mRNA without affecting the abundance of pre-mRNA or the half-life of cytoplasmic mRNA." Molecular and Cellular Biology 13, n.º 3 (marzo de 1993): 1892–902. http://dx.doi.org/10.1128/mcb.13.3.1892.

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The abundance of the mRNA for human triosephosphate isomerase (TPI) is decreased to approximately 20% of normal by frameshift and nonsense mutations that cause translation to terminate at a nonsense codon within the first three-fourths of the reading frame. Results of previous studies inhibiting RNA synthesis with actinomycin D suggested that the decrease is not attributable to an increased rate of cytoplasmic mRNA decay. However, the step in TPI RNA metabolism that is altered was not defined, and the use of actinomycin D, in affecting all polymerase II-transcribed genes, could result in artifactual conclusions. In data presented here, the nonsense codon-mediated reduction in the level of TPI mRNA is shown to be characteristic of both nuclear and cytoplasmic fractions of the cell, indicating that the altered metabolic step is nucleus associated. Neither aberrancies in gene transcription nor aberrancies in RNA splicing appear to contribute to the reduction since there were no accompanying changes in the amount of nuclear run-on transcription, the level of any of the six introns in TPI pre-mRNA, or the size of processed mRNA in the nucleus. Deletion of all splice sites that reside downstream of a nonsense codon does not abrogate the reduction, indicating that the reduction takes place independently of the splicing of a downstream intron. Experiments that placed TPI gene expression under the control of the human c-fos promoter, which can be transiently activated by the addition of serum to serum-deprived cells, verified that there is no detectable effect of a nonsense codon on the turnover of cytoplasmic mRNA.

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31

Cheng, J. y L. E. Maquat. "Nonsense codons can reduce the abundance of nuclear mRNA without affecting the abundance of pre-mRNA or the half-life of cytoplasmic mRNA". Molecular and Cellular Biology 13, n.º 3 (marzo de 1993): 1892–902. http://dx.doi.org/10.1128/mcb.13.3.1892-1902.1993.

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The abundance of the mRNA for human triosephosphate isomerase (TPI) is decreased to approximately 20% of normal by frameshift and nonsense mutations that cause translation to terminate at a nonsense codon within the first three-fourths of the reading frame. Results of previous studies inhibiting RNA synthesis with actinomycin D suggested that the decrease is not attributable to an increased rate of cytoplasmic mRNA decay. However, the step in TPI RNA metabolism that is altered was not defined, and the use of actinomycin D, in affecting all polymerase II-transcribed genes, could result in artifactual conclusions. In data presented here, the nonsense codon-mediated reduction in the level of TPI mRNA is shown to be characteristic of both nuclear and cytoplasmic fractions of the cell, indicating that the altered metabolic step is nucleus associated. Neither aberrancies in gene transcription nor aberrancies in RNA splicing appear to contribute to the reduction since there were no accompanying changes in the amount of nuclear run-on transcription, the level of any of the six introns in TPI pre-mRNA, or the size of processed mRNA in the nucleus. Deletion of all splice sites that reside downstream of a nonsense codon does not abrogate the reduction, indicating that the reduction takes place independently of the splicing of a downstream intron. Experiments that placed TPI gene expression under the control of the human c-fos promoter, which can be transiently activated by the addition of serum to serum-deprived cells, verified that there is no detectable effect of a nonsense codon on the turnover of cytoplasmic mRNA.

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32

Lee, Minho, Minkyung Ryu, Minju Joo, Young-Jin Seo, Jaejin Lee, Hong-Man Kim, Eunkyoung Shin et al. "Endoribonuclease-mediated control of hns mRNA stability constitutes a key regulatory pathway for Salmonella Typhimurium pathogenicity island 1 expression". PLOS Pathogens 17, n.º 2 (1 de febrero de 2021): e1009263. http://dx.doi.org/10.1371/journal.ppat.1009263.

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Bacteria utilize endoribonuclease-mediated RNA processing and decay to rapidly adapt to environmental changes. Here, we report that the modulation of hns mRNA stability by the endoribonuclease RNase G plays a key role in Salmonella Typhimurium pathogenicity. We found that RNase G determines the half-life of hns mRNA by cleaving its 5′ untranslated region and that altering its cleavage sites by genome editing stabilizes hns mRNA, thus decreasing S. Typhimurium virulence in mice. Under anaerobic conditions, the FNR-mediated transcriptional repression of rnc encoding RNase III, which degrades rng mRNA, and simultaneous induction of rng transcription resulted in rapid hns mRNA degradation, leading to the derepression of genes involved in the Salmonella pathogenicity island 1 (SPI-1) type III secretion system (T3SS). Together, our findings show that RNase III and RNase G levels-mediated control of hns mRNA abundance acts as a regulatory pathway upstream of a complex feed-forward loop for SPI-1 expression.

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33

Tumbarski, Yulian, Radosveta Nikolova, Nadezhda Petkova, Ivan Ivanov y Anna Lante. "Biopreservation of Fresh Strawberries by Carboxymethyl Cellulose Edible Coatings Enriched with a Bacteriocin from Bacillus methylotrophicus BM47". Food technology and biotechnology 57, n.º 2 (2019): 230–37. http://dx.doi.org/10.17113/ftb.57.02.19.6128.

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Bacteriocins are a large group of antimicrobial compounds that are synthesized by representatives of the genus Bacillus and lactic acid bacteria. They are used extensively in the food industry as biopreservatives. Incorporated in the composition of edible coatings, bacteriocins can reduce microbial growth and decay incidence in perishable fruits, thus improving product shelf-life and commercial appearance. The present study aims to investigate the effect of edible coatings of 0.5 % carboxymethyl cellulose (CMC) enriched with a purified bacteriocin from Bacillus methylotrophicus BM47 on the shelf-life extension of fresh strawberries. During storage at 4 °C and 75 % relative humidity for 16 days, the measurements of mass loss, decay percentage, total soluble solids (TSS), titratable acidity (TA), pH, organic acids, total phenolic and anthocyanin contents and antioxidant activity were made. The results demonstrate that the application of edible coatings with 0.5 % CMC and 0.5 % CMC with bacteriocin (CMC+B) led to a significant decrease of mass loss in the treated strawberries compared to the uncoated fruit. After the 8th day of storage, significant reductions in decay percentage along with the absence of fungal growth in CMC+B-coated fruit were observed in comparison with the CMC-coated and control strawberries. During the second half of the storage period, CMC and CMC+B treatments reduced TSS amount in the coated fruit compared to the control, but did not affect the increase of TA and decrease of pH values that are normally associated with postharvest changes. The CMC and CMC+B coatings did not prevent the decrease of ascorbic acid, and total phenolic and anthocyanin contents during cold storage. The application of CMC and CMC+B coatings had a significant inhibitory effect on decreasing the antioxidant activity throughout the storage period and maintained the antioxidant levels in both treatments close to the initial value of 76.8 mmol Trolox equivalents per 100 g of fresh mass.

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34

Howlett, Susan E., Scott A. Grandy y Gregory R. Ferrier. "Calcium spark properties in ventricular myocytes are altered in aged mice". American Journal of Physiology-Heart and Circulatory Physiology 290, n.º 4 (abril de 2006): H1566—H1574. http://dx.doi.org/10.1152/ajpheart.00686.2005.

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This study determined whether whole cell Ca2+ transients and unitary sarcoplasmic reticulum (SR) Ca2+ release events are constant throughout adult life or whether Ca2+ release is altered in aging ventricular myocytes. Myocytes were isolated from young adult (∼5 mo old) and aged (∼24 mo old) mice. Spontaneous Ca2+ sparks and Ca2+ transients initiated by field stimulation were detected with fluo-4. All experiments were conducted at 37°C. Ca2+ transient amplitudes were reduced, and Ca2+ transient rise times were abbreviated in aged cells stimulated at 8 Hz compared with young adult myocytes. Furthermore, the incidence and frequency of spontaneous Ca2+ sparks were markedly higher in aged myocytes compared with young adult cells. Spark amplitudes and spatial widths were similar in young adult and aged myocytes. However, spark half-rise times and half-decay times were abbreviated in aged cells compared with younger cells. Resting cytosolic Ca2+ levels and SR Ca2+ stores were assessed by rapid application of caffeine in fura-2-loaded cells. Neither resting Ca2+ levels nor SR Ca2+ content differed between young adult and aged cells. Thus increased spark frequency in aging cells was not attributable to increased SR Ca2+ stores. Furthermore, the decrease in Ca2+ transient amplitude was not due to a decrease in SR Ca2+ load. These results demonstrate that alterations in fundamental SR Ca2+ release units occur in aging ventricular myocytes and raise the possibility that alterations in Ca2+ release may reflect age-related changes in fundamental release events rather than changes in SR Ca2+ stores and diastolic Ca2+ levels.

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35

Samuel, M., B. A. Brown, D. Mikolas, J. Nolen, B. Sherrill, J. Stevenson, J. S. Winfield y Z. Q. Xie. "Measurement of the beta decay half-life ofB17". Physical Review C 37, n.º 3 (1 de marzo de 1988): 1314–17. http://dx.doi.org/10.1103/physrevc.37.1314.

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36

HILLGARTNER, F. Bradley, Tina CHARRON y Kye A. CHESNUT. "Alterations in nutritional status regulate acetyl-CoA carboxylase expression in avian liver by a transcriptional mechanism". Biochemical Journal 319, n.º 1 (1 de octubre de 1996): 263–68. http://dx.doi.org/10.1042/bj3190263.

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Feeding previously starved chicks with a high-carbohydrate, low-fat diet stimulates a 9-fold increase in both the rate of synthesis of acetyl-CoA carboxylase (ACC) and the abundance of its mRNA in liver. To define the steps involved in mediating diet-induced changes in the abundance of ACC mRNA, transcriptional activity was measured with the nuclear run-on assay and multiple DNA probes specific to the ACC gene. ACC transcription was low in livers of starved chicks; feeding them with a high-carbohydrate, low-fat diet induced ACC transcription, increasing it 11-fold. An increase in transcription was detectable at 1 h, was maximal at 5 h and remained high for 26 h. Feeding previously starved chicks with a low-carbohydrate, high-fat diet stimulated a smaller increase (4-fold) in the abundance of ACC mRNA and the transcription of ACC than feeding with a high-carbohydrate, low-fat diet. The half-life of ACC mRNA in liver, as estimated from the kinetics of accumulation and decay of ACC mRNA during high-carbohydrate feeding and starvation, was not changed significantly by dietary manipulation. ACC mRNA was expressed at low levels in heart, pectoral muscle, kidney and brain. The abundance of ACC mRNA in these tissues was not affected by nutritional manipulation. These results demonstrate that nutritional control of the abundance of ACC mRNA in the chicken is liver-specific and is mediated primarily by changes in the rate of transcription of the ACC gene.

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37

Günthard, Huldrych F., Simon D. W. Frost, Andrew J. Leigh-Brown, Caroline C. Ignacio, Kristin Kee, Alan S. Perelson, Celsa A. Spina et al. "Evolution of Envelope Sequences of Human Immunodeficiency Virus Type 1 in Cellular Reservoirs in the Setting of Potent Antiviral Therapy". Journal of Virology 73, n.º 11 (1 de noviembre de 1999): 9404–12. http://dx.doi.org/10.1128/jvi.73.11.9404-9412.1999.

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ABSTRACT In human immunodeficiency virus (HIV)-infected patients treated with potent antiretroviral therapy, the persistence of latently infected cells may reflect the long decay half-life of this cellular reservoir or ongoing viral replication at low levels with continuous replenishment of the population or both. To address these possibilities, sequences encompassing the C2 and V3 domains of HIV-1env were analyzed from virus present in baseline plasma and from viral isolates obtained after 2 years of suppressive therapy in six patients. The presence of sequence changes consistent with evolution was demonstrated for three subjects and correlated with less complete suppression of viral replication, as indicated by the rapidity of the initial virus load decline or the intermittent reappearance of even low levels of detectable viremia. Together, these results provide evidence for ongoing replication. In the remaining three patients, virus recovered after 2 years of therapy was either genotypically contemporary with or ancestral to virus present in plasma 2 years before, indicating that virus recovery had indeed resulted from activation of latently infected cells.

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38

Moreno, B., B. Fernandez-Diez, A. Di Penta y P. Villoslada. "Preclinical studies of methylthioadenosine for the treatment of multiple sclerosis". Multiple Sclerosis Journal 16, n.º 9 (29 de julio de 2010): 1102–8. http://dx.doi.org/10.1177/1352458510375968.

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Background: Methylthioadenosine (MTA) is a natural metabolite with immunomodulatory properties. MTA improves the clinical course and pathology of the animal model of multiple sclerosis, even when therapy is started after disease onset. Objective: Our aim was to compare the efficacy of MTA in ameliorating experimental autoimmune encephalomyelitis (EAE) compared with first line approved therapies, to develop an oral formulation of MTA and to assess its pharmacokinetic profile. Methods: EAE was induced in C57BL/6 mice by immunization with MOG35-55 peptide in Freund’s Adjuvant. Animals were treated with MTA, interferon-beta or Glatiramer acetate starting the day of immunization and the clinical score was collected blind. Pharmacokinetic studies were performed in Sprague Dawley rats by administering MTA by intraperitoneal injection and orally, and collecting blood at different intervals. MTA levels were measured by high-performance liquid chromatography. Results: We found that MTA ameliorated EAE in a dose—response manner. Moreover, the highest dose of MTA (60 mg/kg) was more efficacious than mouse interferon-beta or Glatiramer acetate. We developed a salt of MTA for oral administration, with similar dose—response effect in the EAE model. Combination therapy assays between MTA and interferon-beta or Glatiramer acetate were more effective than the individual therapies. Finally, oral MTA half-life was 20 min, with a Cmax of 80 mg/L and without signs of obvious toxicity (animal death, behavioural changes, liver enzymes). Conclusions: In the EAE model MTA is more efficacious than first line therapies for multiple sclerosis, with a dose— response effect and higher efficacy when combined with interferon-beta or Glatiramer acetate. Oral MTA was also effective in the animal model of multiple sclerosis.

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39

Li, Jing, Micha Levi, Jean-Eric Charoin, Nicolas Frey, Thian Kheoh, Song Ren, Michael Woo, Amita Joshi, Nancy Valente y Nelson ‘Shasha’ Jumbe. "Rituximab Exhibits a Long Half-Life Based on a Population Pharmacokinetic Analysis in Non-Hodgkin’s Lymphoma (NHL) Patients." Blood 110, n.º 11 (16 de noviembre de 2007): 2371. http://dx.doi.org/10.1182/blood.v110.11.2371.2371.

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Abstract The mean serum half life of rituximab reported in the current approved package insert (February 2007) is 76.3 and 205.8 hours following the first and fourth infusions, respectively. This results is based on data from 14 Non-Hodgkin’s Lymphoma (NHL) patients treated with a dose of 375 mg/m2 weekly × 4 analyzed using non-compartmental analysis (NCA). The aims of the current analysis were: to develop a population pharmacokinetic (POP PK) model using a large NHL patient population to investigate possible mechanisms that may explain the observed increase in half-life with time such as a B-cell/tumor burden mediated clearance to identify covariates as potential predictors of PK variability. The population PK analysis was performed using NONMEM V based on 3739 rituximab serum concentration samples from 298 patients who received rituximab as a single agent or in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) therapy from six clinical studies. Tested covariates evaluated included body surface area (BSA), gender, age, race, WHO status, baseline CD19+ counts, sum of the tumor perpendicular diameters (SPD) of tumor and CHOP therapy. A non-parametric bootstrap procedure was used to estimate the precision of model parameters, and the model performance was assessed using visual predictive check. Rituximab concentration data were best described by a two-compartment model with time-varying clearance. Total clearance comprised of two terms, a non-specific clearance pathway (CL1), which remains unchanged throughout treatment, and a specific clearance pathway (CL2, B cells/tumor burden mediated), which decreased at a first-order decay rate from its initial value following the first infusion. The typical population estimates of rituximab nonspecific clearance (CL1), specific clearance (CL2), and central compartment volume of distribution (V1) were 0.14 L/day, 0.59 L/day, and 2.7 L, respectively. Age, gender, race, and WHO performance status had no effect on the PK of rituximab. Covariate analysis revealed that patients with higher CD19 counts or SPD of tumor burden at baseline had a higher rituximab CL2, while V1 varied by body surface area (BSA) and CHOP chemotherapy. However, unexplained inter-individual variability remained high for CL2 following correction for CD19/SPD. Changes from typical V1 values contributed by extreme BSA (1.53 to 2.32 m2) and concurrent CHOP therapy, were relatively minor (27.1% and 19.0%) and explained 27.3% and 5.75% of the inter-individual variability in V1, respectively. Dose adjustment for the tested covariates is not expected to result in a meaningful reduction in rituximab PK variability. Retrospective analysis of rituximab PK using non linear mixed effect modeling confirmed that rituximab elimination decreased following multiple infusions. The median of individual estimates of rituximab terminal half-life was 22 days (range, 6.1 to 52 days), which is typical for immunoglobulin isotype IgG in human and is longer than that reported for humanized anti-CD20 clinical candidates, IMMU106 and of atumumab of 12.0 and 14.3 days, respectively.

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40

Balamucki, Christopher J., Volker W. Stieber, Thomas L. Ellis, Stephen B. Tatter, Allan F. DeGuzman, Kevin P. McMullen, James Lovato et al. "Does dose rate affect efficacy? The outcomes of 256 Gamma Knife surgery procedures for trigeminal neuralgia and other types of facial pain as they relate to the half-life of cobalt". Journal of Neurosurgery 105, n.º 5 (noviembre de 2006): 730–35. http://dx.doi.org/10.3171/jns.2006.105.5.730.

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Object Gamma Knife surgery (GKS) is a treatment option for patients with refractory typical trigeminal neuralgia (TN), TN with atypical features, and atypical types of facial pain. The Gamma Knife’s 201 60Co sources decay with a half-life of 5.26 years. The authors examined whether the decrease in dose rate over 4.6 years between Co source replacements affected the control rates of facial pain in patients undergoing GKS. Methods The authors collected complete follow-up data on 239 of 326 GKS procedures performed in patients with facial pain. Patients were classified by their type of pain. The isocenter of a 4-mm collimator helmet was targeted at the proximal trigeminal nerve root, and the dose (80–90 Gy) was prescribed at the 100% isodose line. Patients reported the amount of pain control following radiosurgery by answering a standardized questionnaire. Eighty percent of patients experienced greater than 50% pain relief, and 56% of patients experienced complete pain relief after GKS. Neither dose rate nor treatment time was significantly associated with either the control rate or degree of pain relief. A significant association between the type of facial pain and the pain control rate after GKS was observed (p < 0.001; Pearson chi-square test). In their statistical analysis, the authors accounted for changes in prescription dose over time to prevent the dose rate from being a confounding variable. There was no observable effect of the dose rate or of the treatment duration within the typical period to source replacement. Conclusions Patients with facial pain appear to receive consistent treatment with GKS at any time during the first half-life of the Co sources.

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Chamboredon, Sandrine, Delphine Ciais, Agnès Desroches-Castan, Pierre Savi, Françoise Bono, Jean-Jacques Feige y Nadia Cherradi. "Hypoxia-inducible factor-1α mRNA: a new target for destabilization by tristetraprolin in endothelial cells". Molecular Biology of the Cell 22, n.º 18 (15 de septiembre de 2011): 3366–78. http://dx.doi.org/10.1091/mbc.e10-07-0617.

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Endothelial cells (ECs) are the primary sensors of variations in blood oxygen concentrations. They use the hypoxia-sensitive stabilization of the hypoxia-inducible factor-1α (HIF-1α) transcription factor to engage specific transcriptional programs in response to oxygen changes. The regulation of HIF-1α expression is well documented at the protein level, but much less is known about the control of its mRNA stability. Using small interfering RNA knockdown experiments, reporter gene analyses, ribonucleoprotein immunoprecipitations, and mRNA half-life determinations, we report a new regulatory mechanism of HIF-1α expression in ECs. We demonstrate that 1) sustained hypoxia progressively decreases HIF-1α mRNA while HIF-1α protein levels rapidly peak after 3 h and then slowly decay; 2) silencing the mRNA-destabilizing protein tristetraprolin (TTP) in ECs reverses hypoxia-induced down-regulation of HIF-1α mRNA; 3) the decrease in the half-life of Luciferase-HIF-1α-3′UTR reporter transcript that is observed after prolonged hypoxia is mediated by TTP; 4) TTP binds specifically to HIF-1α 3′UTR; and 5) the most distal AU-rich elements present in HIF-1α 3′UTR (composed of two hexamers) are sufficient for TTP-mediated repression. Finally, we bring evidence that silencing TTP expression enhances hypoxia-induced increase in HIF-1α protein levels with a concomitant increase in the levels of the carbonic anhydrase enzyme CA IX, thus suggesting that TTP physiologically controls the expression of a panel of HIF-1α target genes. Altogether, these data reveal a new role for TTP in the control of gene expression during the response of endothelial cell to hypoxia.

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Whitehouse, Tony, Martin Stotz, Valerie Taylor, Ray Stidwill y Mervyn Singer. "Tissue oxygen and hemodynamics in renal medulla, cortex, and corticomedullary junction during hemorrhage-reperfusion". American Journal of Physiology-Renal Physiology 291, n.º 3 (septiembre de 2006): F647—F653. http://dx.doi.org/10.1152/ajprenal.00475.2005.

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Previous studies of intrarenal perfusion and tissue oxygenation have produced a wide range of results and have not matched tissue oxygen tension (tPo2) with concurrent changes in flow in three distinct regions. We thus used an anesthetized rat model of hemorrhage-reperfusion to address this question. Combined tpo2/laser-Doppler fiber-optic probes were simultaneously sited in cortical, corticomedullary (CMJ), and medullary regions of the left kidney. Total renal blood flow was measured in separate experiments. Recordings were made during exsanguination of 10 and 20% of estimated blood volume at 10-min intervals, followed by shed-blood resuscitation after a further 10 min. The decay in tpo2 was then recorded following total cessation of blood flow, allowing estimation of local oxygen consumption. During exsanguination, tPo2 was maintained in all intrarenal regions, despite significant falls in blood pressure and total renal blood flow. However, intrarenal flow was redistributed with reduced cortical, unchanged CMJ, and increased medullary blood flow. After resuscitation, significant rises above baseline were seen in blood pressure and in tpo2 across all regions. Whereas cortical and medullary flows regained baseline values, CMJ flow fell. The ratio of tpo2 to microvascular blood flow increased significantly in all regions during resuscitation, suggesting decreased oxygen consumption. On total cessation of blood flow, the cortex and CMJ showed significant increases in the oxygen decay half-life, consistent with decreased consumption. To our knowledge, this is the first quantitative demonstration of a markedly heterogeneous intrarenal cardiorespiratory response to a hemodynamic insult, with effects most marked at the corticomedullary junction.

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Pape, M. E. y K. H. Kim. "Transcriptional regulation of acetyl coenzyme A carboxylase gene expression by tumor necrosis factor in 30A-5 preadipocytes." Molecular and Cellular Biology 9, n.º 3 (marzo de 1989): 974–82. http://dx.doi.org/10.1128/mcb.9.3.974.

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Acetyl coenzyme A (acetyl-CoA) carboxylase activity, amount, and mRNA levels increase during the differentiation of 30A-5 preadipocytes to adipocytes. Tumor necrosis factor (TNF) completely prevents this differentiation, with concomitant inhibition of acetyl-CoA carboxylase mRNA accumulation. To investigate the mechanisms by which TNF prevents acetyl-CoA carboxylase mRNA accumulation, we determined the effect of TNF on the transcription rate of the carboxylase gene and the half-life of carboxylase mRNA. Nuclear runoff transcription assays revealed no differences in the number of RNA polymerase molecules actively engaged in transcription of the acetyl-CoA carboxylase gene in preadipocytes, adipocytes, TNF-treated preadipocytes, or at any time during the course of differentiation. However, changes in adipsin, glycerophosphate dehydrogenase, and actin mRNAs, whose levels are also differentiation dependent, can be accounted for in part by changes in the number of polymerase complexes on their respective genes. To determine whether TNF caused a decrease in the stability of carboxylase RNA transcripts, we measured the rate of decay of prelabeled acetyl-CoA carboxylase mRNA. Control and TNF-treated cells showed no difference between the apparent half-lives of acetyl-CoA carboxylase mRNAs (9 h). However, the rate of acetyl-CoA carboxylase mRNA synthesis in vivo was decreased three- to fourfold in the presence of TNF. These data demonstrate that TNF prevents accumulation of acetyl-CoA carboxylase mRNA during preadipocyte differentiation by decreasing the rate of acetyl-CoA carboxylase gene transcription. However, transcriptional control is not due to a change in the number of RNA polymerase complexes actively engaged in carboxylase transcript elongation which could be measured by a number runoff assay. Instead, transcriptional control may be related to the rate at which RNA polymerase traverses the acetyl-CoA carboxylase gene.

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44

Pape, M. E. y K. H. Kim. "Transcriptional regulation of acetyl coenzyme A carboxylase gene expression by tumor necrosis factor in 30A-5 preadipocytes". Molecular and Cellular Biology 9, n.º 3 (marzo de 1989): 974–82. http://dx.doi.org/10.1128/mcb.9.3.974-982.1989.

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Acetyl coenzyme A (acetyl-CoA) carboxylase activity, amount, and mRNA levels increase during the differentiation of 30A-5 preadipocytes to adipocytes. Tumor necrosis factor (TNF) completely prevents this differentiation, with concomitant inhibition of acetyl-CoA carboxylase mRNA accumulation. To investigate the mechanisms by which TNF prevents acetyl-CoA carboxylase mRNA accumulation, we determined the effect of TNF on the transcription rate of the carboxylase gene and the half-life of carboxylase mRNA. Nuclear runoff transcription assays revealed no differences in the number of RNA polymerase molecules actively engaged in transcription of the acetyl-CoA carboxylase gene in preadipocytes, adipocytes, TNF-treated preadipocytes, or at any time during the course of differentiation. However, changes in adipsin, glycerophosphate dehydrogenase, and actin mRNAs, whose levels are also differentiation dependent, can be accounted for in part by changes in the number of polymerase complexes on their respective genes. To determine whether TNF caused a decrease in the stability of carboxylase RNA transcripts, we measured the rate of decay of prelabeled acetyl-CoA carboxylase mRNA. Control and TNF-treated cells showed no difference between the apparent half-lives of acetyl-CoA carboxylase mRNAs (9 h). However, the rate of acetyl-CoA carboxylase mRNA synthesis in vivo was decreased three- to fourfold in the presence of TNF. These data demonstrate that TNF prevents accumulation of acetyl-CoA carboxylase mRNA during preadipocyte differentiation by decreasing the rate of acetyl-CoA carboxylase gene transcription. However, transcriptional control is not due to a change in the number of RNA polymerase complexes actively engaged in carboxylase transcript elongation which could be measured by a number runoff assay. Instead, transcriptional control may be related to the rate at which RNA polymerase traverses the acetyl-CoA carboxylase gene.

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45

Guo, Caixia, Lisa Savage, Kevin D. Sarge y Ok-Kyong Park-Sarge. "Gonadotropins Decrease Estrogen Receptor-β Messenger Ribonucleic Acid Stability in Rat Granulosa Cells*". Endocrinology 142, n.º 6 (1 de junio de 2001): 2230–37. http://dx.doi.org/10.1210/endo.142.6.8102.

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Abstract We have previously shown that the preovulatory LH surge down-regulates estrogen receptor-β (ERβ) messenger RNA (mRNA) levels selectively in the granulosa cells of preovulatory follicles. To gain insight into the underlying mechanisms, we examined whether the LH-induced loss of ERβ mRNA expression in rat granulosa cells is attributable to the hormone-induced changes at the level of transcription and/or mRNA degradation. When the rate of ERβ gene transcription was assessed in cultured granulosa cells, by nuclear run-off assays, we observed only a marginal effect of hCG on ERβ gene transcription. In contrast, when ERβ mRNA levels were estimated in granulosa cells that were cultured in the presence of 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole (DRB), an RNA synthesis inhibitor, we observed a significant inhibitory effect of human CG (hCG) on ERβ mRNA expression at a magnitude similar to that observed in the absence of DRB. Forskolin (FSK) and 2-O-tetradecanol-phorbol-13-acetate (TPA), pharmacological agents that mimic LH actions in granulosa cells, also showed similar effects. Thus, these results suggest that LH decreases ERβ mRNA expression in the granulosa cells of preovulatory follicles, primarily by destabilizing the preexisting ERβ mRNA. We next determined the decay rate of the ERβ mRNA in granulosa cells that were cultured in the presence of DRB and additional hCG, FSK, or TPA for various time periods, by estimating ERβ mRNA levels, using semiquantitative RT-PCR assays and subsequent linear regression analyses. The half-life of the ERβ mRNA in the presence of vehicle was 17.87 ± 1.2 h (n = 4). hCG dramatically decreased the half-life of the ERβ mRNA (4.85 ± 0.49 h, n = 4). Similarly, both FSK and TPA decreased the half-life of the ERβ mRNA to 3.57 ± 0.31 h and 4.02± 0.13 h, respectively. We extended these findings by examining whether the LH-induced down-regulation of the ERβ mRNA is cycloheximide-sensitive. When granulosa cells were cultured in the presence of cycloheximide, a protein synthesis inhibitor, the inhibitory effects of hCG, FSK, and TPA on ERβ mRNA levels were abolished. Similar results were obtained in the presence or absence of DRB, indicating that the hormone-induced destabilization of the ERβ mRNA is coupled with translation processes. Taken together, our results demonstrate that LH decreases ERβ mRNA expression, predominantly at the posttranscriptional level, in a cycloheximide-sensitive manner.

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Dolinski, Michelle J., Alan W. P. Poon y Werner Rodejohann. "Neutrinoless Double-Beta Decay: Status and Prospects". Annual Review of Nuclear and Particle Science 69, n.º 1 (19 de octubre de 2019): 219–51. http://dx.doi.org/10.1146/annurev-nucl-101918-023407.

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Neutrinoless double-beta decay is a forbidden, lepton-number-violating nuclear transition whose observation would have fundamental implications for neutrino physics, theories beyond the Standard Model, and cosmology. In this review, we summarize the theoretical progress to understand this process, the expectations and implications under various particle physics models, and the nuclear physics challenges that affect the precise predictions of the decay half-life. We also provide a synopsis of the current and future large-scale experiments that aim to discover this process in physically well-motivated half-life ranges.

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47

Mills, Robert W., David J. Mountford, Jonathon P. Coleman, Carl Metelko, Matthew Murdoch y Yan-Jie Schnellbach. "Modelling of the anti-neutrino production and spectra from a Magnox reactor". EPJ Web of Conferences 170 (2018): 07008. http://dx.doi.org/10.1051/epjconf/201817007008.

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The anti-neutrino source properties of a fission reactor are governed by the production and beta decay of the radionuclides present and the summation of their individual anti-neutrino spectra. The fission product radionuclide production changes during reactor operation and different fissioning species give rise to different product distributions. It is thus possible to determine some details of reactor operation, such as power, from the anti-neutrino emission to confirm safeguards records. Also according to some published calculations, it may be feasible to observe different anti-neutrino spectra depending on the fissile contents of the reactor fuel and thus determine the reactor's fissile material inventory during operation which could considerable improve safeguards. In mid-2014 the University of Liverpool deployed a prototype anti-neutrino detector at the Wylfa R1 station in Anglesey, United Kingdom based upon plastic scintillator technology developed for the T2K project. The deployment was used to develop the detector electronics and software until the reactor was finally shutdown in December 2015. To support the development of this detector technology for reactor monitoring and to understand its capabilities, the National Nuclear Laboratory modelled this graphite moderated and natural uranium fuelled reactor with existing codes used to support Magnox reactor operations and waste management. The 3D multi-physics code PANTHER was used to determine the individual powers of each fuel element (8×6152) during the year and a half period of monitoring based upon reactor records. The WIMS/TRAIL/FISPIN code route was then used to determine the radionuclide inventory of each nuclide on a daily basis in each element. These nuclide inventories were then used with the BTSPEC code to determine the anti-neutrino spectra and source strength using JEFF-3.1.1 data. Finally the anti-neutrino source from the reactor for each day during the year and a half of monitored reactor operation was calculated. The results of the preliminary calculations are shown and limitations in the methods and data discussed.

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M.K. Preethi Rajan, R. K. Biju R.K. Biju y K. P. Santhosh K.P. Santhosh. "Beta Decay Studies of Nuclides in the Heavy Region". Journal of Nuclear Physics, Material Sciences, Radiation and Applications 8, n.º 1 (9 de noviembre de 2020): 43–53. http://dx.doi.org/10.15415/jnp.2020.81006.

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In the present work we studied the β-decay of various isotopes in the heavy region using the empirical formula of Fiset and Nix. It is found from the half-life that as the neutron number increases the possibility of β-decay increases. From the dependence of beta decay half-life on neutron number of parent and Q-value, we modified empirical formula of Fiset and Nix for beta decay half-life. We also developed an empirical formula for the Z-value of most stable isobar against β-decay. From the study of mass parabola for different isobars with mass number ranging from 200-223 it was found that the lowest point in the parabola, which is the Z-value of most stable isobar against β-decay, matches well with our formula predictions.

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Mccue, KF y AD Hanson. "Effect of Soil Salinity on the Expression of Betaine Aldehyde Dehydrogenase in Leaves: Investigation of Hydraulic, Ionic and Biochemical Signals." Functional Plant Biology 19, n.º 5 (1992): 555. http://dx.doi.org/10.1071/pp9920555.

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Betaine aldehyde dehydrogenase (BADH) catalyses the last step in glycine betaine synthesis. The levels of BADH enzyme and BADH mRNA have previously been shown to be increased several-fold by salt stress. To characterise this induction more thoroughly, BADH mRNA levels and enzyme activities were analysed in leaves of sugar beet plants (Beta vulgaris L.) subjected to different salinisation regimes. Following a salt shock (transfer from 0 to 400 mM NaCI) BADH enzyme activity rose slowly for several days. In contrast, BADH mRNA level first decreased for several hours, and then increased. When salt was leached from the rooting medium of salinised plants, BADH enzyme activity declined, with a half-life of more than 4 days. However, the level of BADH mRNA declined sharply with an apparent half-life of 2 h showing that transcription of the BADH gene or the stability of BADH mRNA in leaves can respond very dynamically to salinity changes around the root. In plants which had been gradually salinised and then held at various NaCl concentrations, the steady state level of enzyme rose continuously between 0 and 500 mM NaCl, whereas that of BADH mRNA reached a plateau at 100 mM NaCl. In general, the observed BADH mRNA fluctuations could not be satisfactorily explained by assuming them to be responses to hydraulic signals. This suggests the participation of a non-hydraulic signal or signals coming from the root. The non-hydraulic signal is unlikely to be NaCl, because leaf disks exposed to salt concentrations typical of the apoplast of salinised leaves did not accumulate BADH mRNA. A biochemical messenger is thus implied. Although abscisic acid application to leaf disks elicited significant increases in BADH mRNA level, these were several-fold smaller than those observed in leaves of intact salinised plants, suggesting the involvement of some other substance.

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50

KISHIMOTO, TADAFUMI. "STUDY OF 48-Ca DOUBLE BETA DECAY". International Journal of Modern Physics E 18, n.º 10 (noviembre de 2009): 2129–33. http://dx.doi.org/10.1142/s0218301309014421.

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Neutrino-less double beta decay (0νββ) is currently known to be only experiment to verify whether lepton number conservation is violated. The violation is the key to create matter dominated universe by the so-called Leptogenesys. We have been studying double beta decay of 48 Ca . First stage of the experiment was carried out by using the ELEGANT VI detector system. We gave the best lower limit of the half life of 0νββ of 48 Ca . We have been developing CANDLES detector system to sense much longer life-time region. We have developed techniques to reduce further backgrounds. One of the techniques has been used in the ELEGANTS VI system and improved further the half life limit. The CADLES detector system will be installed Kamioka underground laboratory next year. I describe these studies.

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