P538 The reliability of patient performed fecal calprotectin testing

Abstract Background For measurement of fecal calprotectin (FC) a stool sample is sent to the laboratory, where calprotectin is extracted and determined. With the CALiaGold (CG) tube, especially designed for home sampling, this labor-intensive extraction procedure in the laboratory can be bypassed. Furthermore, the home-use of this buffer containing extraction device can potentially prevent FC degradation. We aimed to determine the reliability of patient performed FC extraction, to assess whether degradation during transport can be prevented and to determine its usability by patients. Methods In this prospective cross-sectional observational study, 4 CG tubes and 2 regular tubes were filled from the same bowel movement by patients with inflammatory bowel disease. Half of the tubes were directly frozen, others were sent to the laboratory by mail. Four more CG tubes were filled at the laboratory; 2 from the native sample sent by mail and 2 from the directly frozen native sample. The FC levels were measured by a particle enhanced turbidimetric immunoassay. The directly frozen tubes were used for the comparison between patient and analyst performed extractions, while the tubes sent by regular mail were used to determine FC stability during transport. The usability was assessed with a questionnaire. Results Fifty-three patients were included. No significant difference was found in patient performed extractions compared to analyst performed extractions in samples with FC levels <200 µg/g. However, in samples with FC levels ≥200 µg/g patient performed extractions were significantly lower (p=0.014). When patients were divided in 3 groups (i.e. FC levels <50ug/g, 50–200 µg/g and >200 µg/g), the resulting Cohen’s kappa coefficient was 0.787 (95% CI: 0.646–0.928), reflecting a substantial agreement between patient and analyst performed extraction. A median FC increase of 28.6% was found in the native samples after one freeze-thaw cycle, potentially explaining the higher FC levels in the analyst performed extractions from the directly frozen native sample. Patients sampling imprecision was higher (p<0.01, median CV 17%) compared to the analyst (median CV 8%). Higher FC levels were found in the CG tubes sent by mail compared to native samples, reflecting less FC degradation. The questionnaire revealed that 62% of patients preferred the CG tube and 8% the conventional tube. Conclusion Patient performed FC extraction is a realistic alternative sampling method, especially since the freeze-thaw process in the native samples may have led to higher values in the analyst performed extractions. Moreover, usage may prevent FC degradation during transport and patients prefer the use of the extraction device.

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Studies on Repository Compound Stability in DMSO under Various Conditions

CrossRef Listing of Deleted DOIs ◽

10.1177/1087057103008003007 ◽

2003 ◽

Vol 8 (3) ◽

pp. 292-304 ◽

Cited By ~ 76

Author(s):

Xueheng Cheng ◽

Jill Hochlowski ◽

Hua Tang ◽

Darlene Hepp ◽

Carl Beckner ◽

...

Keyword(s):

Internal Standard ◽

Structural Diversity ◽

Nitrogen Atmosphere ◽

Storage Container ◽

Freeze Thaw ◽

Long Term Storage ◽

Thaw Cycle ◽

Significant Difference ◽

Freeze Thaw Cycle

The chemical stability of repository compounds is affected by various environmental conditions during long-term storage. Studies were carried out to evaluate the effects of the following potential causes of instability of compounds in DMSO at a 10-mM concentration: water, oxygen, freeze/thaw cycles, and storage container material. A set of compounds was selected for the study based on structural diversity and functional group representation. Compound concentration was determined with liquid chromatography/ultraviolet spectroscopy/mass spectrometry (LC/UV/MS) analysis relative to an internal standard added to each sample. An accelerated study was conducted, and results demonstrate that most compounds are stable for 15 weeks at 40 °C. Water is more important in causing compound loss than oxygen. The freeze/thaw cycle study was done with freezing at -15 °C and thawing under nitrogen atmosphere at 25 °C. Two methods were used to redissolve compounds after thawing: agitation and repeated aspiration/dispense. The results indicate no significant compound loss after 11 freeze/thaw cycles. Compound recovery was also measured from glass and polypropylene containers for 5 months at room temperature, and no significant difference was found for these 2 types of containers. ( Journal of Biomolecular Screening 2003:292-304)

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Healing of Chronic Wounds with Platelet-Derived Growth Factors from Single Donor Platelet-Rich Plasma following One Freeze-Thaw Cycle. A Cross-Sectional Study

Journal of Clinical Medicine ◽

10.3390/jcm10245762 ◽

2021 ◽

Vol 10 (24) ◽

pp. 5762

Author(s):

Vidán-Estévez Vidán-Estévez ◽

Sánchez-Herráez Sánchez-Herráez ◽

Escalante-Barrigón Escalante-Barrigón ◽

Seco-Calvo Seco-Calvo

Keyword(s):

Chronic Wounds ◽

Platelet Rich Plasma ◽

Cross Sectional Study ◽

P Value ◽

Sectional Study ◽

Cross Sectional ◽

Freeze Thaw ◽

Single Donor ◽

Thaw Cycle ◽

Freeze Thaw Cycle

Chronic non-healing wounds (CNHWs) may be associated with trauma or idiopathic in nature and are difficult to treat. Our objective was to assess the use of platelet-derived growth factor (PDGF) from single-donor platelets (al-PRP), using one freeze-thaw cycle, for treating CNHWs. We conducted a cross-sectional study. A total of 23 CNHWs being treated with al-PRP. The al-PRP treatment can be considered successful in well over half (n = 13, 56.5%) of the wounds. We found that all the wounds treated for up to 7 weeks showed partial or complete healing, while those treated for between 8 and 12 weeks did not show healing, healing again being successful in cases in which treatment was extended to more than 13 weeks (85.7%). Using chi-square tests, this relationship was found to be highly significant (p < 0.001, chi2 = 19.51; p value = 0.00006). Notably, Cramer’s V coefficient was very high (0.921), indicating that the effect size of PRP treatment duration on healing is very large (84.8%). We could suggest that the use of al-PRP in the healing of CNHWs is a promising approach. Further studies with larger sample sizes and long follow-ups are needed to obtain multivariate models to explain which factors favour the healing of ulcers treated with PRP

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59 Incubation of frozen/thawed bovine embryos

Reproduction Fertility and Development ◽

10.1071/rdv33n2ab59 ◽

2021 ◽

Vol 33 (2) ◽

pp. 136

Author(s):

D. Hobbs ◽

C. Holcomb ◽

J. Gibbons

Keyword(s):

Poor Quality ◽

Future Research ◽

Bovine Embryo ◽

Bovine Embryos ◽

Test Quality ◽

Freeze Thaw ◽

Thaw Cycle ◽

Significant Difference ◽

Freeze Thaw Cycle ◽

Fetal Bovine

High-quality, properly developed bovine embryos are crucial to the embryo transfer industry and enable cryopreservation; however, ∼30% of invivo embryos do not develop to the appropriate stage and are discarded. Currently, frozen/thawed embryos are transferred directly into a recipient, and the quality of embryos post-thaw is seldom evaluated. The objective of this experiment was to evaluate frozen/thawed bovine embryos immediately post-thaw, and again after incubation in different environments. Frozen/thawed bovine embryos (n=30/treatment) processed for direct transfer were thawed (30°C water; 30s) and graded and staged in holding medium. Embryos were then placed into either holding medium, phosphate-buffered saline supplemented with 15% fetal bovine serum (v/v) and antibiotic/antimycotic (2μL mL−1) (PBS+FBS), or a commercially available invitro culture (IVC) medium for ∼18h. Embryos in holding medium and PBS+FBS were loaded into 0.25-mL straws with the appropriate medium, and the straws were sealed and submerged in 38.5°C water. The IVC embryos were placed individually into 25-μL culture drops on tissue-coated 60-mm plastic Petri dishes overlaid with mineral oil and incubated (18h) at 38.5°C in 5% CO2 and air at 100% humidity. Embryos were then collected, regraded, and staged, and comparisons among groups were analysed via the Kruskal–Wallis H-test. Quality score of all embryos decreased by at least one-third post-thaw; however, the developmental stage was unaffected by the freeze/thaw cycle. Following incubation, all embryos suffered a significant (P<0.05) decrease in embryo quality but the IVC group demonstrated less (P<0.05) of a decline in resulting quality (Table 1). The IVC group demonstrated significant development (P<0.05) during incubation compared to the Holding and PBS+FBS groups (Table 1) indicating that on average, viability was maintained during IVC. Regardless of group, the zona pellucida was damaged during the freeze/thaw process in 31.1% of embryos. These data illuminated embryo damage after cryopreservation, and demonstrated that short-term invitro incubation of frozen/thawed embryos (IVC) facilitated continued development and may be a practical mechanism to salvage poor quality or developmentally suppressed embryos. Future research will focus on salvaging fresh embryos that are classified as degenerate and may prove useful in the bovine embryo industry, and for cattle producers alike, by ultimately increasing the number of transferable embryos that would otherwise be discarded. Table 1. Descriptive statistics (mean±s.e.m.) of bovine embryos pre-freeze and post-thaw and incubation Item Media Pre-freeze Post-thaw Post-incubation Grade Holding 1.4±0.1 1.7±0.1a 3.3±0.1b,x PBS+FBS 1.2±0.1 1.6±0.1a 3.1±0.1b,x IVC1 1.2±0.1 1.6±0.1a 2.5±0.2b,y Stage Holding 4.0±0.1 4.0±0.1 3.9±0.1x PBS+FBS 4.7±0.2 4.4±0.2 4.5±0.2y IVC 4.3±0.1 4.3±0.1a 5.8±0.2b,z a,b, x–zDifferent superscripts within row (a, b) and column (x, y, z) indicate a significant difference (P<0.05, Kruskal-Wallis H-test). 1Invitro culture medium.

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Experimental investigation on combined modification for micro physicochemical characteristics of coal by compound reagents and liquid nitrogen freeze-thaw cycle

Fuel ◽

10.1016/j.fuel.2021.120287 ◽

2021 ◽

Vol 292 ◽

pp. 120287

Author(s):

Weibo Han ◽

Gang Zhou ◽

Junpeng Wang ◽

Wenjing Jiang ◽

Qian Zhang ◽

...

Keyword(s):

Experimental Investigation ◽

Liquid Nitrogen ◽

Physicochemical Characteristics ◽

Freeze Thaw ◽

Thaw Cycle ◽

Freeze Thaw Cycle

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The effect of freeze–thaw cycle on the low-temperature properties of asphalt fine aggregate matrix utilizing bending beam rheometer

Cold Regions Science and Technology ◽

10.1016/j.coldregions.2016.02.008 ◽

2016 ◽

Vol 125 ◽

pp. 101-107 ◽

Cited By ~ 20

Author(s):

Xiangbing Gong ◽

Pedro Romero ◽

Zejiao Dong ◽

Daniel Scott Sudbury

Keyword(s):

Low Temperature ◽

Fine Aggregate ◽

Bending Beam Rheometer ◽

Freeze Thaw ◽

Thaw Cycle ◽

Freeze Thaw Cycle ◽

Fine Aggregate Matrix

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Effect of freeze–thaw cycle on physical and mechanical properties and damage characteristics of sandstone

Scientific Reports ◽

10.1038/s41598-021-91842-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Longxiao Chen ◽

Kesheng Li ◽

Guilei Song ◽

Deng Zhang ◽

Chuanxiao Liu

Keyword(s):

Mechanical Properties ◽

Shear Failure ◽

Triaxial Compression ◽

Physical And Mechanical Properties ◽

Freeze Thaw ◽

Damage Characteristics ◽

Large Pore ◽

Natural Rock ◽

Thaw Cycle ◽

Freeze Thaw Cycle

AbstractRock deterioration under freeze–thaw cycles is a concern for in-service tunnel in cold regions. Previous studies focused on the change of rock mechanical properties under unidirectional stress, but the natural rock mass is under three dimensional stresses. This paper investigates influences of the number of freeze–thaw cycle on sandstone under low confining pressure. Twelve sandstone samples were tested subjected to triaxial compression. Additionally, the damage characteristics of sandstone internal microstructure were obtained by using acoustic emission (AE) and mercury intrusion porosimetry. Results indicated that the mechanical properties of sandstone were significantly reduced by freeze–thaw effect. Sandstone’ peak strength and elastic modulus were 7.28–37.96% and 6.38–40.87% less than for the control, respectively. The proportion of super-large pore and large pore in sandstone increased by 19.53–81.19%. We attributed the reduced sandstone’ mechanical properties to the degenerated sandstone microstructure, which, in turn, was associated with increased sandstone macropores. The macroscopic failure pattern of sandstone changed from splitting failure to shear failure with an increasing of freeze–thaw cycles. Moreover, the activity of AE signal increased at each stage, and the cumulative ringing count also showed upward trend with the increase of freeze–thaw number.

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Non-linear creep damage model of sandstone under freeze-thaw cycle

Journal of Central South University ◽

10.1007/s11771-021-4656-3 ◽

2021 ◽

Vol 28 (3) ◽

pp. 954-967

Author(s):

Jie-lin Li ◽

Long-yin Zhu ◽

Ke-ping Zhou ◽

Hui Chen ◽

Le Gao ◽

...

Keyword(s):

Damage Model ◽

Creep Damage ◽

Freeze Thaw ◽

Thaw Cycle ◽

Linear Creep ◽

Non Linear ◽

Freeze Thaw Cycle ◽

Creep Damage Model

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Strength and Microscopic Damage Mechanism of Yellow Sandstone with Holes under Freezing and Thawing

Advances in Civil Engineering ◽

10.1155/2020/5921901 ◽

2020 ◽

Vol 2020 ◽

pp. 1-13 ◽

Cited By ~ 1

Author(s):

Huren Rong ◽

Jingyu Gu ◽

Miren Rong ◽

Hong Liu ◽

Jiayao Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Pore Size ◽

Power Function ◽

Damage Mechanism ◽

Uniaxial Compression Test ◽

Freezing And Thawing ◽

Freeze Thaw ◽

Thaw Cycle ◽

Freeze Thaw Cycle ◽

Microscopic Damage

In order to study the damage characteristics of the yellow sandstone containing pores under the freeze-thaw cycle, the uniaxial compression test of saturated water-stained yellow sandstones with different freeze-thaw cycles was carried out by rock servo press, the microstructure was qualitatively analyzed by Zeiss 508 stereo microscope, and the microdamage mechanism was quantitatively studied by using specific surface area and pore size analyzer. The mechanism of weakening mechanical properties of single-hole yellow sandstone was expounded from the perspective of microstructure. The results show the following. (1) The number of freeze-thaw cycles and single-pore diameter have significant effects on the strength and elastic modulus of the yellow sandstone; the more the freeze-thaw cycles and the larger the pore size, the lower the strength of the yellow sandstone. (2) The damage modes of the yellow sandstone containing pores under the freeze-thaw cycle are divided into five types, and the yellow sandstone with pores is divided into two areas: the periphery of the hole and the distance from the hole; as the number of freeze-thaw cycles increases, different regions show different microscopic damage patterns. (3) The damage degree of yellow sandstone is different with freeze-thaw cycle and pore size. Freeze-thaw not only affects the mechanical properties of yellow sandstone but also accelerates the damage process of pores. (4) The damage of the yellow sandstone by freeze-thaw is logarithmic function, and the damage of the yellow sandstone is a power function. The damage equation of the yellow sandstone with pores under the freezing and thawing is a log-power function nonlinear change law and presents a good correlation.

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Studies the Properties of Polyaspartic Polyurea Coated Concrete under Coaction of Salt Fog and Freeze-Thaw

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.455-456.781 ◽

2012 ◽

Vol 455-456 ◽

pp. 781-785

Author(s):

Ping Lu ◽

Xin Mao Li ◽

Xue Qiang Ma ◽

Wei Bo Huang

Keyword(s):

Elastic Modulus ◽

Frost Resistance ◽

Dynamic Elastic Modulus ◽

Freeze Thaw ◽

Decrease Rate ◽

Thaw Cycle ◽

Freeze Thaw Cycle ◽

Salt Fog

. This paper mainly studied the properties of PAE polyurea coated concrete under coactions of salt fog and freeze-thaw. After exposed salt fog conditions for 200d, T3, B2, F2 and TM four coated concrete relative dynamic elastic modulus have small changes, but different coated concrete variation amplitude is different. T3 coated concrete after 100 times of freeze-thaw cycle the relative dynamic elastic modulus began to drop, 200 times freeze-thaw cycle ends, relative dynamic elastic modulus variation is the largest, decrease rate is 95%, TM concrete during 200 times freeze-thaw cycle, relative dynamic elastic modulus almost no change, B2 concrete and F2 concrete the extent of change between coating T3 and TM. After 300 times the freeze-thaw cycle coated concrete didn't appear freeze-thaw damage phenomenon. Four kinds of coating concrete relative dynamic elastic modulus variation by large to small order: T3 coated concrete > B2 coated concrete >F2 coated concrete > TM coated concrete, concrete with the same 200d rule. Frost resistance order, by contrast, TM coated concrete > B2 coated concrete > F2 coated concrete > T3 coated concrete.

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