scholarly journals The CANDELLE experiment for characterization of neutron sensitivity of LiF TLDs

2018 ◽  
Vol 170 ◽  
pp. 04014 ◽  
Author(s):  
M.Le Guillou ◽  
A. Billebaud ◽  
A. Gruel ◽  
G. Kessedjian ◽  
O. Méplan ◽  
...  
Keyword(s):  
Neutron Field ◽  
Early Assessment ◽  
Power Flux ◽  
Design Studies ◽  
Thermoluminescent Dosimeters ◽  
Highly Sensitive ◽  
Gamma Field ◽  
Nuclear Heating

As part of the design studies conducted at CEA for future power and research nuclear reactors, the validation of neutron and photon calculation schemes related to nuclear heating prediction are strongly dependent on the implementation of nuclear heating measurements. Such measurements are usually performed in low-power reactors, whose core dimensions are accurately known and where irradiation conditions (power, flux and temperature) are entirely controlled. Due to the very low operating power of such reactors (of the order of 100 W), nuclear heating is assessed by using dosimetry techniques such as thermoluminescent dosimeters (TLDs). However, although they are highly sensitive to gamma radiation, such dosimeters are also, to a lesser extent, sensitive to neutrons. The neutron dose depends strongly on the TLD composition, typically contributing to 10-30% of the total measured dose in a mixed neutron/gamma field. The experimental determination of the neutron correction appears therefore to be crucial to a better interpretation of doses measured in reactor with reduced uncertainties. A promising approach based on the use of two types of LiF TLDs respectively enriched with lithium-6 and lithium-7, precalibrated both in photon and neutron fields, has been recently developed at INFN (Milan, Italy) for medical purposes. The CANDELLE experiment is dedicated to the implementation of a pure neutron field “calibration” of TLDs by using the GENEPI-2 neutron source of LPSC (Grenoble, France). Those irradiation conditions allowed providing an early assessment of the neutron components of doses measured in EOLE reactor at CEA Cadarache with 10% uncertainty at 1σ.

scholarly journals Characterization of Hapten-Protein Conjugates: Antibody Generation and Immunoassay Development for Chlorophenoxyacetic Acid Pesticides

2009 ◽  
Vol 92 (6) ◽  
pp. 1773-1779 ◽  
Author(s):  
Robin C Boro ◽  
K Vikas Singh ◽  
C Raman Suri
Keyword(s):  
Inhibitory Concentration ◽  
Dichlorophenoxyacetic Acid ◽  
Protein Conjugation ◽  
Protein Conjugates ◽  
Highly Sensitive ◽  
Ic50 Values ◽  
Chlorophenoxyacetic Acid ◽  
2,4 Dichlorophenoxyacetic Acid

Abstract The generation of specific and sensitive antibodies against small molecules is greatly dependent upon the characteristics of the hapten-protein conjugates. In this study, we report a new fluorescence-based method for the characterization of hapten-protein conjugates. The method is based on an effect promoted by hapten-protein conjugation density upon the fluorescence intensity of the intrinsic tryptophan chromophore molecules of the protein. The proposed methodology is applied to quantify the hapten-protein conjugation density for two different chlorophenoxyacetic acid pesticides, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4-dichlorophenoxybutyric acid (2,4-DB), coupled to carrier protein. Highly sensitive anti-2,4-D and anti-2,4-DB antibodies were obtained using these well-characterized hapten-protein conjugates. The generated antibodies were used in an immunoassay format demonstrating inhibitory concentration (IC50) values equal to 30 and 7 ng/mL for 2,4-D and 2,4-DB, respectively. Linearity was observed in the concentration range between 0.1500 ng/mL with LODs around 4 and 3 ng/mL for 2,4-D and 2,4-DB, respectively, in standard water samples. The proposed method was successfully applied for the determination of the extent of hapten-protein conjugation to produce specific antibodies for immunoassay development against pesticides.

scholarly journals Characterization of the gamma flux in a tangential channel of the CENM TRIGA MARK II research reactor

2020 ◽  
Vol 225 ◽  
pp. 04030
Author(s):  
A. Gruel ◽  
D. Fourmentel ◽  
C. El Younoussi ◽  
B. El Bakkari ◽  
Y. Boulaich ◽  
...  
Keyword(s):  
Steady State ◽  
Nuclear Data ◽  
Neutron Field ◽  
Photon Propagation ◽  
The Core ◽  
Thermal Maximum ◽  
Gamma Field ◽  
Triga Mark Ii ◽  
Gamma Flux

The CNESTEN (National Center for Energy Sciences and Nuclear Technology, Morocco) operates a TRIGA Mark II reactor, which can reach a thermal maximum power at steady state of 2 MW. In reactors devoted to research and experiments, it is mandatory to characterize the neutron and photon fields in the irradiation positions. Together with a computational model of the core, it ensures the ability to reach the requested uncertainties when performing experiments, such as detectors testing, irradiation for hardening or nuclear data measurements. The neutron field of different irradiation positions has been characterized by dosimetry techniques and compared to the MCNP full model of the reactor. Preliminary photon propagation calculations are also performed with this model, but up to now, no experimental validation of the results exists. The aim of the newly set collaboration between CEA and CNESTEN is to characterize the gamma field of these positions. The first position investigated is the part of the NB1 tangential channel closest to the core. Among gamma measurements techniques, and according to the constraints arising from using this channel, it was chosen to use thermos- and optically stimulated luminescent detectors. This paper presents the experiments carried out in September 2018 as well as their results. Three detectors types were used: TLD400 (CaF2:Mn), TLD700 (7LiF:Mg,Ti) and OSLD (Al2O3:C). Measurements were performed in several steps: background measurements, transient measurements (divergence phase + SCRAM), and irradiation at steady state. In the end, these measurements will provide a dose as well as a gamma flux value for this position.

scholarly journals Generation of CD1 tetramers as a tool to monitor glycolipid–specific T cells

2003 ◽  
Vol 358 (1433) ◽  
pp. 875-877 ◽  
Author(s):  
Stephan D. Gadola ◽  
Anastasios Karadimitris ◽  
Nathan R. Zaccai ◽  
Mariolina Salio ◽  
Nicolas Dulphy ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Functional Characterization ◽  
Hla Class I ◽  
Lipid Complex ◽  
Highly Sensitive ◽  
M Proteins ◽  
Human T Lymphocyte

CD1 molecules are β 2 m–associated HLA class–I–like glycoproteins which have the unique ability to present glycolipid and phospholipid antigens to specific T lymphocytes. To study the biology of CD1 and its role in human disease we developed novel techniques for generation of recombinant CD1/lipid complexes by in vitro refolding. Fluorescent tetrameric complexes made from soluble recombinant CD1d/α–galactosylceramide complexes allowed highly sensitive and specific ex vivo and in vitro detection and functional characterization of novel human T–lymphocyte populations. Furthermore, protein crystals were obtained from soluble recombinant CD1b/β 2 m–proteins loaded either with phosphatidylinositol or ganglioside GM2, which led to the first atomic structure determination of a CD1/lipid complex. The analysis of these crystal structures clarified how CD1b molecules can bind lipid ligands of different size, and revealed a broader spectrum of potential CD1b ligands than previously predicted.

Sensitive UHPLC–MS/MS method for the determination of tacrolimus in minipig whole blood

Bioanalysis ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 519-532
Author(s):  
Manuel Álvarez ◽  
María Clotilde Hernández ◽  
Pere Macià ◽  
Josep Maria Jansat ◽  
Sonia Sentellas
Keyword(s):  
Whole Blood ◽  
Solid Phase ◽  
Topical Administration ◽  
Sample Treatment ◽  
Organ Rejection ◽  
Highly Sensitive ◽  
Interday Precision ◽  
Pharmacokinetic Behavior

Background: Tacrolimus, a potent immunosuppressant drug widely used systemically to reduce the risk of organ rejection in transplants, has been repositioned for topical treatment of atopic dermatitis. Results & methodology: This work describes the optimization of a new method for the determination of tacrolimus in whole blood after topical administration. Sample treatment consisted of an automated procedure based on protein precipitation followed by solid-phase extraction. The present method showed good performance with quantitation limits of 10 pg ml-1 and intra- and interday precision and accuracy lower than 15 and 10%, respectively. Conclusion: A new highly sensitive UHPLC–MS/MS method has been developed enabling a better characterization of the minipig blood plasma pharmacokinetic behavior of tacrolimus after topical administration.

Characterization of Impressed Current Technique to Model Corrosion of Reinforcement in Concrete

2020 ◽  
Vol 11 (1) ◽  
pp. 93-99
Author(s):  
Abu Zakir Morshed ◽  
Sheikh Shakib ◽  
Tanzim Jahin
Keyword(s):  
Immersion Time ◽  
Chloride Content ◽  
Engineering Science ◽  
Coastal Regions ◽  
Faraday’S Law ◽  
Current Technique ◽  
Corrosion Cell ◽  
Impressed Current

Corrosion of reinforcement is an important durability concern for the structures exposed to coastal regions. Since corrosion of reinforcement involves long periods of time, impressed current technique is usually used to accelerate the corrosion of reinforcement in laboratories. Characterization of impressed current technique was the main focus of this research,which involved determination of optimum chloride content and minimum immersion time of specimens for which the application of Faraday’s law could be efficient. To obtain optimum chloride content, the electrolytes in the corrosion cell were prepared similar to that of concrete pore solutions. Concrete prisms of 200 mm by 200 mm by 300 mm were used to determine the minimum immersion time for saturation. It was found that the optimum chloride content was 35 gm/L and the minimum immersion time for saturation was 140 hours. Accounting the results, a modified expression based on Faraday’s law was proposed to calculate weight loss due to corrosion. Journal of Engineering Science 11(1), 2020, 93-99

The Determination of Sense via Deleuze and Blanchot: Paradoxes of the Habitual, the Immemorial, and the Eternal Return

2008 ◽  
Vol 2 (2) ◽  
pp. 155-177 ◽  
Author(s):  
Eugene Brently Young
Keyword(s):  
Eternal Return

Eternal return is the paradox that accounts for the interplay between difference and repetition, a dynamic at the heart of Deleuze's philosophy, and Blanchot's approach to this paradox, even and especially through what it elides, further illuminates it. Deleuze draws on Blanchot's characterisations of difference, forgetting, and the unlivable to depict the ‘sense’ produced via eternal return, which, for Blanchot, is where repetition implicates or ‘carries’ pure difference. However, for Deleuze, difference and the unlivable are also developed by the living repetition or ‘contraction’ of habit, which results in his distinctive characterization of ‘force’, ‘levity’, and sense in eternal return.

Sign in / Sign up

Export Citation Format

Share Document