The Effect of Freeze/Thaw Cycles on the Stability of Compounds in DMSO

2003 ◽  
Vol 8 (2) ◽  
pp. 210-215 ◽  
Author(s):  
Barbara A. Kozikowski ◽  
Thomas M. Burt ◽  
Debra A. Tirey ◽  
Lisa E. Williams ◽  
Barbara R. Kuzmak ◽  
...  
Keyword(s):  
High Throughput Screening ◽  
High Performance ◽  
Atmospheric Conditions ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Time Period ◽  
Freeze Thaw Cycle ◽  
Low Humidity ◽  
The Stability ◽  
Short Time

A diverse set of 320 compounds from the Procter & Gamble Pharmaceuticals organic compound repository was prepared as 20-mM DMSO solutions and stored at 4°C under argon in pressurized canisters to simulate a low-humidity environment. The plates were subjected to 25 freeze/thaw cycles while being exposed to ambient atmospheric conditions after each thaw to simulate the time and manner by which compound plates are exposed to the atmosphere during typical liquid-handling and high-throughput screening processes. High-performance liquid chromatography–mass spectrometry with evaporative light-scattering detection was used to quantitate the amount of compound remaining after every 5th freeze/thaw cycle. Control plates were stored either at room temperature under argon or at 4°C under argon without freeze/thaw cycling and were evaluated at the midpoint and the endpoint of the study. The study was conducted over a short time period (i.e., 7 weeks) to minimize the effect of compound degradation over time due to the exposure of the compounds to DMSO.The results from this study will be used to determine the maximum number of freeze/thaw cycles that can be achieved while maintaining acceptable compound integrity.(Journal of Biomolecular Screening 2003:210-215)

scholarly journals Stability of Plasma Amyloid-β 1–40, Amyloid-β 1–42, and Total Tau Protein over Repeated Freeze/Thaw Cycles

2020 ◽  
Vol 10 (1) ◽  
pp. 46-55
Author(s):  
Huei-Chun Liu ◽  
Ming-Jang Chiu ◽  
Chin-Hsien Lin ◽  
Shieh-Yueh Yang
Keyword(s):  
Tau Protein ◽  
Statistical Significance ◽  
Amyloid Β ◽  
Freeze Thaw ◽  
Total Tau ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Fresh Plasma ◽  
The Stability ◽  
T Tau

Introduction: Blood biomarkers of Alzheimer’s disease (AD) have attracted much attention of researchers in recent years. In clinical studies, repeated freeze/thaw cycles often occur and may influence the stability of biomarkers. This study aims to investigate the stability of amyloid-β 1–40 (Aβ1–40), amyloid-β 1–42 (Aβ1–42), and total tau protein (T-tau) in plasma over freeze/thaw cycles. Methods: Plasma samples from healthy controls (n = 2), AD patients (AD, n =3) and Parkinson’s disease patients (PD, n = 3) were collected by standardized procedure and immediately frozen at –80°C. Samples underwent 5 freeze/thaw (–80°C/room temperature) cycles. The concentrations of Aβ1–40, Aβ1–42, and T-tau were monitored during the freeze/thaw tests using an immunomagnetic reduction (IMR) assay. The relative percentage of concentrations after every freeze/thaw cycle was calculated for each biomarker. Results: A tendency of decrease in the averaged relative percentages over samples through the freeze and thaw cycles for Aβ1–40 (100 to 97.11%), Aβ1–42 (100 to 94.99%), and T-tau (100 to 95.65%) was found. However, the decreases were less than 6%. For all three biomarkers, no statistical significance was found between the levels of fresh plasma and those of the plasma experiencing 5 freeze/thaw cycles (p > 0.1). Conclusions: Plasma Aβ1–40, Aβ1–42, and T-tau are stable through 5 freeze/thaw cycles measured with IMR.

scholarly journals The Effects of a Single Freeze-Thaw Cycle on Concentrations of Nutritional, Noncommunicable Disease, and Inflammatory Biomarkers in Serum Samples

2021 ◽  
Author(s):  
Ransi Ann Abraham ◽  
Garima Rana ◽  
Praween K. Agrawal ◽  
Robert Johnston ◽  
Avina Sarna ◽  
...  
Keyword(s):  
Large Scale ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Noncommunicable Disease ◽  
Noncommunicable Diseases ◽  
Serum Samples ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
The Stability

Abstract Background The stability of biological samples is vital for reliable measurements of biomarkers in large-scale survey settings, which may be affected by freeze-thaw procedures. We examined the effect of a single freeze-thaw cycle on 13 nutritional, noncommunicable diseases (NCD), and inflammatory bioanalytes in serum samples. Method Blood samples were collected from 70 subjects centrifuged after 30 minutes and aliquoted immediately. After a baseline analysis of the analytes, the samples were stored at − 70°C for 1 month and reanalyzed for all the parameters. Mean percentage differences between baseline (fresh blood) and freeze-thaw concentrations were calculated using paired sample t-tests and evaluated according to total allowable error (TEa) limits (desirable bias). Results Freeze-thaw concentrations differed significantly (p < 0.05) from baseline concentrations for soluble transferrin receptor (sTfR) (− 5.49%), vitamin D (− 12.51%), vitamin B12 (− 3.74%), plasma glucose (1.93%), C-reactive protein (CRP) (3.45%), high-density lipoprotein (HDL) (7.98%), and cholesterol (9.76%), but they were within respective TEa limits. Low-density lipoprotein (LDL) (− 0.67%), creatinine (0.94%), albumin (0.87%), total protein (1.00%), ferritin (− 0.58%), and triglycerides (TAG) (2.82%) concentrations remained stable following the freeze-thaw cycle. In conclusion, single freeze-thaw cycle of the biomarkers in serum/plasma samples after storage at − 70°C for 1 month had minimal effect on stability of the studied analytes, and the changes in concentration were within acceptable limit for all analytes.

scholarly journals The Effect of Tanreqing Injection on the Pharmacokinetics of Sirolimus in Rats

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Feng Zhang ◽  
Liang Sun ◽  
Jianxiu Zhai ◽  
Tianyi Xia ◽  
Wei Jiang ◽  
...  
Keyword(s):  
High Performance ◽  
Room Temperature ◽  
Matrix Effects ◽  
Thaw Cycle ◽  
Relative Standard ◽  
The Matrix ◽  
Freeze Thaw Cycle ◽  
Liquid Chromatography Tandem Mass ◽  
The Stability ◽  
First Time

To evaluate the effect of Tanreqing injection on the pharmacokinetics of sirolimus in rats, a high performance liquid chromatography tandem mass spectrometry method was developed for sirolimus assay in whole blood. Calibration curve of sirolimus was acquired over a concentration ranging from 2.5 to 100 ng/mL with r2= 0.9955. The matrix effects and extraction recoveries of sirolimus ranged from 144% to 152% and from 80% to 96%, respectively. The inter- and intraday relative standard deviations were both <10%. The stability investigation showed that the blood samples were stable for 30-day-storage at -20°C, for 8 h storage at room temperature, for 24 h storage in the auto-sampler at 4°C, and for three freeze-thaw cycle process. The pharmacokinetic results demonstrated that the Cmax, AUC, and AUMC of sirolimus in rats (7.5 mg/kg, i.g.) were increased after beincoadministration with Tanreqing Injection at 2.5, 5.0, and 7.5 mL/kg (i.v.), respectively, or at 5 min, 2 h, and 4 h (5.0 mL/kg, i.v.) after SRL dosing, respectively. For the first time, the results proved the herb-drug interaction between Tanreqing Injection and sirolimus and accordingly suggested avoiding concurrent reception of those two drugs for patients.

Phenotyping of Hyperlipoproteinemias

1970 ◽  
Vol 16 (6) ◽  
pp. 507-511 ◽  
Author(s):  
James Winkelman ◽  
Donald R Wybenga ◽  
Frank A Ibbott
Keyword(s):  
Cellulose Acetate ◽  
Room Temperature ◽  
Cellulose Acetate Electrophoresis ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
The Stability

Abstract The stability of serum specimens collected for cellulose acetate electrophoresis of lipoproteins has been studied for each of the hyperlipoproteinemia phenotypes. In general, samples kept at room temperature for three days are still suitable for analysis. On longer standing, artifacts can cause misinterpretation of strips, or render them completely unreadable. If specimens are stored at refrigerator or freezer temperatures, deterioration is retarded but the period of stability after they are returned to room temperature is unaltered. A second freeze-thaw cycle makes specimens unsuitable for analysis. Samples can be stored at refrigerator temperatures for at least 28 days and at freezer temperatures for at least 14 days if one freeze-thaw cycle is used.

Comparison of Multiple Freeze-Thaw Cycles of High-Performance Concrete Test Beams and Concrete Beams Loaded Test

2013 ◽  
Vol 351-352 ◽  
pp. 570-573
Author(s):  
Zhi Qiang Li ◽  
Xian Chun Zheng ◽  
Xiao Hong Cong
Keyword(s):  
Mechanical Properties ◽  
Concrete Structure ◽  
High Performance ◽  
High Performance Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Experimental Basis ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

This study focuses on the following: analysis of the basic mechanical properties of freeze-thaw cycles BFRP composite; freeze-thaw cycle on BFRP reinforced concrete structures force performance; provide experimental basis for the the basalt FRP freeze-thaw environment concrete structure andtheoretical support.

Experiment Study on the Effect of GGBFS on Frost Resistance of Concrete

2014 ◽  
Vol 629-630 ◽  
pp. 207-212 ◽  
Author(s):  
Shi Yi Zhang ◽  
Ying Fang Fan ◽  
Qi Wang
Keyword(s):  
Electron Microscopy ◽  
High Performance ◽  
Plain Concrete ◽  
Industrial Wastes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Scanning Electron

High volume utilization of industrial wastes and by products is the solution for high disposal coast. The anti-frost of high performance concrete is a key factor for safe utilization of concrete structure containing industrial wastes under severe environment. In this paper, to understand the property on anti-frost of high performance containing ground granulated blast furnace slag (GGBFS) under cold marine environment. Some comparison studies were conducted on plain concrete by rapid freeze-thaw cycle test. During the rapid freeze-thaw cycle test, the mass loss and relative elastic modulus were measured regularly at the prescribed conditioning ages. The development of microstructure in concrete was analyzed through scanning electron microscopy (SEM) and X-ray diffraction (XRD). The rapid freeze-thaw cycle test results show that the plain concrete was destroyed severely at 150 freeze-thaw cycles. After 225 freeze-thaw cycles, the mass loss and the relative dynamic modulus of elasticity of GGBFS concrete decrease 1.3% and 26.11%, respectively, that indicates that GGBFS significantly improve the anti-frost performance of concrete; The addition of GGBFS can accelerate the cement hydration reaction, promote more Ca (OH)2 crystals shift to C-S-H gel and help to increase the density of the micro-structure of concrete, which can prevent the formation of micro-cracks and suppress the propagation of cracks and thus effectively improve the durability of concrete. KEY WORDS: GGBFS; freeze-thaw durability; microstructure; scanning electron microscopy; X-ray diffraction.

scholarly journals The Influence of Regional Freeze–Thaw Cycles on Loess Landslides: Analysis of Strength Deterioration of Loess with Changes in Pore Structure

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3047
Author(s):  
Zuyong Li ◽  
Gengshe Yang ◽  
Hui Liu
Keyword(s):  
Pore Structure ◽  
Triaxial Compression ◽  
Strength Loss ◽  
Loess Landslide ◽  
Strength Deterioration ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Loess Landslides ◽  
The Stability

The loess landslide in Gaoling District of Xi’an, Shaanxi in China is closely related to the seasonal freeze–thaw cycle, which is manifested by the destruction of pore structure and strength deterioration of the loess body under freeze–thaw conditions. In order to study the relationship between macro-strength damage and pore structure deterioration of saturated loess under freeze–thaw conditions and its influence on the stability of landslides, this paper explores the effect of freeze–thaw cycles on the strength of saturated undisturbed loess through triaxial compression test, and explores the micro-microstructure changes of saturated undisturbed loess through scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR). This is to analyze the evolution of the pore structure and strength loss evolution of saturated loess during the freeze–thaw process, and to describe the freeze–thaw damage of saturated undisturbed loess through the change of porosity and strength deterioration. Then, the internal correlation expression between the porosity change and the strength degradation is established to realize the verification analysis of the test data based on the correlation model. The research results show that: (1) As the number of freeze–thaw cycles increases, the peak strength loss rate gradually increases, and the strength deterioration of saturated loess becomes more and more obvious. (2) The freeze–thaw cycle will lead to the development of pores and cracks in the sample, accompanied by the generation of new cracks, which will cause the deterioration of the pore structure of the sample as a whole. (3) The response of strength damage and porosity deterioration of saturated undisturbed loess is roughly similar under the freeze–thaw cycle. The change in porosity can be measured to better reflect the strength deterioration of saturated loess. Therefore, the change of pore structure of undisturbed loess under freeze–thaw cycle conditions is tested by field sampling and indoor tests to reflect the phenomenon of strength deterioration, thereby analyzing the stability of loess slopes.

Study on Frost Resistance of High Performence Concrete Resistance to Chloride Ion

2012 ◽  
Vol 174-177 ◽  
pp. 1312-1316
Author(s):  
Sheng Ai Cui ◽  
Yue Zhong Ye ◽  
Sheng Tan Dou ◽  
Fei Fu
Keyword(s):  
Frost Resistance ◽  
High Speed ◽  
High Performance ◽  
High Performance Concrete ◽  
Chloride Ion ◽  
Freeze Thaw ◽  
Slag Powder ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Electric Flux

Taking bridge pile of Beijing-Shanghai high speed railway as background, this paper studies frost resistance of high performance concrete resistance to chloride ion, including double-doped mineral (fly ash and slag powder) concrete, two minerals and preservative composition concrete. Quick frost method was adopted in the freeze-thaw cycle test, and frost resistance of high performance concrete was assessed by relative dynamic modulus of elasticity and mass loss ratios. Meanwhile, the electric flux values of specimens were measured after freeze-thaw cycles for assessing chloride ion penetration. Test results show: The frost resistance of both C35, C50 double-doped mineral concrete and C35 two minerals and preservative composition concrete is good, and chloride ion permeability is very low after freeze-thaw cycles.

Experimental Study on Freeze-Thaw Resistance Durablilty of High Performance Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 393-397 ◽  
Author(s):  
Jun Fang Huo ◽  
Xiao Xia Ji ◽  
Hui Yang
Keyword(s):  
Fly Ash ◽  
Large Volume ◽  
High Performance ◽  
High Performance Concrete ◽  
Test Results ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle ◽  
Resistance Performance ◽  
Maximum Weight Loss

Freeze-thaw cycle experiments on high performance concrete were carried out while cement was respectively replaced by fly ash for 30%～50%. The test results showed that maximum weight loss rate of concrete was 1.78% and minimum relative dynamic elastic modulus was 94.08% after 300 freeze-thaw cycles for high performance concrete based on low water-cement ratio, efficient air-water-reducing agent and large quantities of industrial waste fly ash. The test data were far less than limits of 5% and 60% in specification. Freeze-thaw resistance performance of high performance concrete with large volume fly ash was excellent according to test results. The high performance concrete with large volume fly ash can meet the requirements of frost resistance performance of concrete in the cold regions. Particularly, it can be fit for the railway concrete engineering.

Sign in / Sign up

Export Citation Format

Share Document