scholarly journals The effect of freeze‐thaw cycles on determination of immunoreactive plasma adrenocorticotrophic hormone concentrations in horses

2020 ◽  
Vol 34 (3) ◽  
pp. 1350-1356 ◽  
Author(s):  
Ke Hu ◽  
Allison J. Stewart ◽  
Ka Y. Yuen ◽  
Sophia Hinrichsen ◽  
Elizabeth L. Dryburgh ◽  
...  
Keyword(s):  
Adrenocorticotrophic Hormone ◽  
Freeze Thaw

Measurement of progesterone in sheep using a commercial ELISA kit for human plasma

2021 ◽  
pp. 104063872110435
Author(s):  
Valeria Pasciu ◽  
Maria Nieddu ◽  
Elena Baralla ◽  
Cristian Porcu ◽  
Francesca Sotgiu ◽  
...  
Keyword(s):  
Enzyme Immunoassay ◽  
Human Plasma ◽  
Method Validation ◽  
Plasma Progesterone ◽  
Freeze Thaw ◽  
Elisa Kit ◽  
Stability Data ◽  
Human Use ◽  
Species Specific

Determination of serum or plasma progesterone (P4) concentrations is important to recognize pregnant and non-pregnant ewes, and also to predict the number of carried lambs. The 2 most common methodologies for the detection of plasma P4 are radioimmunoassay (RIA) and enzyme immunoassay (EIA). RIA is very expensive, and not all laboratories are equipped to perform this test; EIA is commercially available for human use, but only a few companies produce species-specific kits, which are expensive. We verified for ovine plasma a less expensive and easily available ELISA kit (DiaMetra) designed to quantify P4 in humans. Pools of ovine and human plasma were used to compare repeatability, accuracy, sensitivity, and stability of P4 measured by the DiaMetra kit. Repeatability data were within 15%, and accuracy values were ~90% for both plasma matrices. Stability data showed a loss of <20% for freeze–thaw and <30% for 30-d storage. All parameters were acceptable under international guidelines for method validation. The human ELISA kit was used successfully to quantify plasma P4 in 26 ewes during pregnancy until delivery. P4 concentrations were also correlated with the number of carried lambs.

scholarly journals Accelerated method for the determination of freeze-thaw resistance of concrete

2015 ◽  
Vol 1 ◽  
pp. 170 ◽  
Author(s):  
Sergey Nikolskiy ◽  
Olga Pertseva
Keyword(s):  
High Efficiency ◽  
Reference Method ◽  
Mean Value ◽  
Nondestructive Method ◽  
National Standard ◽  
Labor Input ◽  
Standard Specification ◽  
Freeze Thaw ◽  
Mathematical Relation

<p class="R-AbstractKeywords"><span lang="EN-US">Main purpose of this research is to create the new reference method of determining the freeze-thaw resistance of concrete that is characterized by small labor input, high efficiency and a wide application scope. The offered method is based on measurement of long strength by nondestructive method. During this research, the theoretical analysis of concrete's specimen dependence on freeze-thaw resistance and energy, which is emitted by a specimen during destruction, has been carried out.  Freeze-thaw resistance of a specimen is calculated as the mathematical relation of these energies, and the freeze-thaw resistance of concrete is calculated as an arithmetic mean value across specimens. </span></p><p class="R-AbstractKeywords"><span lang="EN-US">To prove the method correctness it was realized on 10 concrete specimens. Age of specimens cosolidation is 88 days. Speciments of concrete mortar were prepared using a mix of portland cement 400 (12,3%), sand of dimentions 0.6-5 mm (24,7%), granite macadam of dimentions 5-20 mm (55,4%) and water (7,4%). Freeze-thaw resistance such mortar was determed earlier by method, approved national standard specification, it was equal 105 cycles. According dimentions by new offered method freeze-thaw resistance such mortar is equal 107 cycles and its confidence interval is equal 5,4 (probability P = 0,95). Therefore, spread of results could be casual and the offered method is correct.</span></p>

P0301FIT FOR PURPOSE VALIDATION OF A CLINICAL ASSAY FOR THE DETECTION OF SERUM LEVELS OF GALACTOSE-DEFICIENT IMMUNOGLOBULIN A1 (GD-IGA1) IN PATIENTS WITH IGA NEPHROPATHY (IGAN)

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Laura Sponton ◽  
Hulin Jin ◽  
Markus Fluck ◽  
Yusuke Suzuki ◽  
Amy Kao
Keyword(s):  
Quantitative Determination ◽  
Human Serum ◽  
Iga Nephropathy ◽  
Calibration Curve ◽  
Clinical Studies ◽  
Serum Samples ◽  
Freeze Thaw ◽  
Healthy Donors ◽  
Validation Parameters

Abstract Background and Aims Analysis of serum or plasma from patients with IgA nephropathy (IgAN) has confirmed the presence of elevated levels of circulating immune complexes containing Gd-IgA1 (Czerkinsky 1986). New sensitive and reasonably specific noninvasive tests are emerging to guide the therapeutic strategy that is applicable to all stages of IgAN (Suzuki 2014). Here we are reporting the fit for purpose validation of an ELISA method for the quantitative determination of Gd-IgA1 in human serum samples to support biomarker investigations in clinical studies of Merck KGaA, Darmstadt. Method The assay was developed based on a commercially available immunoassay kit. The dynamic range of the calibration curve was determined from 1.56 ng/mL (LLOQ) to 100 ng/mL (ULOQ). With a minimum required dilution of 200-fold and standard assay volume of 50.0 μL, the range of the method in matrix was from 312 ng/mL to 20, 000 ng/mL. In assay validation phase, multiple validation parameters were evaluated, which included minimum required dilution (MRD), calibration curve, matrix effect, Intra- & Inter run accuracy & precision, selectivity, and parallelism. Additional validation parameters include sample stability (short/long term, freeze-thaw) and batch-to-batch comparison. Results All samples measured for intra & Inter - assay precision, accuracy, fulfilled the specifications according to the acceptance criteria. The selectivity was assessed using blank serum matrix from 10 individuals: the result indicated that matrix components in serum did not interfere with the detection of Gd-IgA1. Parallelism assessment was performed successfully for both samples from healthy donors and IgAN patient samples up to dilution factor (DF) 3200 (serum samples from healthy donors were determined up to DF 1600). All DF-corrected results within the assay range were determined with %CV ≤ 30.0%. Batch to batch comparison was assessed successfully based on the known shelf life of the kit. Short term stability using QC samples were given for up to 24hrs at room temperature. Freeze-thaw stability was given for up to 3 cycles at -20°C±5°C and -75°C±15°C. The investigations were performed according to general guidelines for method validation and applicable regulations. The results of investigated validation parameters fulfilled the requirements and recommendations, generally accepted for bioanalytical projects. Conclusion The present validation qualified the method for the quantitative determination of Gd-IgA1 in human serum samples from clinical studies.

scholarly journals Research on Deterioration Mechanism of Concrete Materials in an Actual Structure

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Shiping Zhang ◽  
Xiang Dong ◽  
Houxian Zhang ◽  
Min Deng
Keyword(s):  
Concrete Structure ◽  
Frost Resistance ◽  
Field Survey ◽  
Petrographic Analysis ◽  
Actual Structure ◽  
Freeze Thaw ◽  
Alkali Aggregate Reaction ◽  
Deterioration Mechanism ◽  
Concrete Materials

The cause for deterioration of the concrete structure located in severe environment has been explored both in field and in laboratory. Serious cracking and spalling appeared upon surface of the concrete structure soon after the structure was put into service. Both alkali-aggregate reaction and freeze-thaw cycles may result in similar macro visible cracking and spalling. The possibility of alkali-aggregate reaction was excluded by both field survey and lab examination such as chemical analysis, petrographic analysis, and determination of alkali reactivity of aggregates. According to results of freeze-thaw cycles, impermeability testing, and microstructure analysis, it is deduced that the severe environmental conditions plus the relatively inferior frost resistance cause the deterioration of concrete. Usage of air entraining admixture can improve frost resistance and impermeability. Furthermore, new approaches to mitigate the deterioration of concrete used in severe environmental condition are discussed.

scholarly journals Novel determination of effective freeze–thaw cycles as drivers of ecosystem change

2020 ◽  
Vol 49 (2) ◽  
pp. 314-323
Author(s):  
Edward P. Boswell ◽  
Anita M. Thompson ◽  
Nick J. Balster ◽  
Alex W. Bajcz
Keyword(s):  
Ecosystem Change ◽  
Freeze Thaw
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