Vitrifying multiple embryos in different arrangements does not alter the cooling rate

Vitrification is the most common method of cryopreservation of gametes in fertility clinics due to its improved survival rates compared to slow freezing techniques. For the Open Cryotop® vitrification device, the number of oocytes, or embryos, mounted onto a single device can vary. In this work, a mathematical model is developed for the cooling of oocytes, or embryos, that is solved computationally, to investigate whether varying the number of samples mounted onto the Open Cryotop® affects the cooling rates, and therefore survival rates, of vitrified samples. Several realistic spatial arrangements of oocytes/embryos are examined, determining the temperature of the system over time, which highlights the effect of spatial arrangement on the rate of cooling. Results indicate that neither spatial arrangement nor the number of mounted oocytes, or embryos, has a large effect on cooling rates, so long as the volume of the cryoprotectant remains minimal. Under the manufacturer's guidelines, clinical decisions regarding the number and arrangement of oocytes or embryos placed on a device can be varied, whilst maintaining rapid cooling.

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Analyses of Nocturnal Temperature Cooling-Rate Response to Historical Local-Scale Urban Land-Use/Land Cover Change

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-10-05014.1 ◽

2011 ◽

Vol 50 (9) ◽

pp. 1872-1883 ◽

Cited By ~ 24

Author(s):

Winston T. L. Chow ◽

Bohumil M. Svoma

Keyword(s):

Land Use ◽

Land Cover ◽

Cooling Rate ◽

Rural Areas ◽

Urban Areas ◽

Local Scale ◽

Urban Land Use ◽

Cooling Rates ◽

Near Surface ◽

Over Time

AbstractUrbanization affects near-surface climates by increasing city temperatures relative to rural temperatures [i.e., the urban heat island (UHI) effect]. This effect is usually measured as the relative temperature difference between urban areas and a rural location. Use of this measure is potentially problematic, however, mainly because of unclear “rural” definitions across different cities. An alternative metric is proposed—surface temperature cooling/warming rates—that directly measures how variations in land-use and land cover (LULC) affect temperatures for a specific urban area. In this study, the impact of local-scale (<1 km2), historical LULC change was examined on near-surface nocturnal meteorological station temperatures sited within metropolitan Phoenix, Arizona, for 1) urban versus rural areas, 2) areas that underwent rural-to-urban transition over a 20-yr period, and 3) different seasons. Temperature data were analyzed during ideal synoptic conditions of clear and calm weather that do not inhibit surface cooling and that also qualified with respect to measured near-surface wind impacts. Results indicated that 1) urban areas generally observed lower cooling-rate magnitudes than did rural areas, 2) urbanization significantly reduced cooling rates over time, and 3) mean cooling-rate magnitudes were typically larger in summer than in winter. Significant variations in mean nocturnal urban wind speeds were also observed over time, suggesting a possible UHI-induced circulation system that may have influenced local-scale station cooling rates.

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Boar semen can tolerate rapid cooling rates prior to freezing

Reproduction Fertility and Development ◽

10.1071/rd10216 ◽

2011 ◽

Vol 23 (5) ◽

pp. 681 ◽

Cited By ~ 22

Author(s):

Jorge D. Juarez ◽

Inma Parrilla ◽

Juan M. Vazquez ◽

Emilio A. Martinez ◽

Jordi Roca

Keyword(s):

Cooling Rate ◽

Flow Cytometric Analysis ◽

Membrane Integrity ◽

Annexin V ◽

Objective Evaluation ◽

Membrane Lipid ◽

Cooling Rates ◽

Rapid Cooling ◽

Motile Cells ◽

Boar Spermatozoa

Two experiments were performed in the present study that demonstrated that boar spermatozoa are capable of surviving rapid cooling rates within a range of 15–5°C before freezing. Boar ejaculates diluted in Beltsville thawing solution (BTS) (1 : 1, v/v) were held at 17–20°C and shipped over a 24-h time period from two AI centres to a cryobiology laboratory, where they were pooled (Experiment 1) or cryopreserved individually (Experiment 2) using a standard 0.5-mL straw freezing protocol. The effects of cooling before freezing were assessed after thawing through the objective evaluation of sperm motility and flow cytometric analysis of membrane integrity, acrosomal status, changes in membrane lipid architecture monitored by merocyanine and annexin V binding and intracellular production of reactive oxygen species. In Experiment 1 (six replicates), two semen pools (five ejaculates per pool) were cooled from 15 to 5°C at rates of 0.08, 0.13, 0.40 and 1.50°C min–1. These cooling rates did not result in any significant differences (P > 0.05) in any of the post-thaw sperm assessments, even in thawed samples incubated under capacitation conditions. In Experiment 2, three individual ejaculates from 16 boars were slowly (0.08°C min–1) or rapidly (1.5°C min–1) cooled before freezing. A consistent interboar variability (P < 0.01) was detected, which was independent of the cooling rate used. Cooling rate only significantly influenced (P < 0.05) sperm assessments in four of 16 boars, which exhibited slightly higher percentages of motile cells and intact plasma and acrosomal membranes in the samples that had been cooled slowly. These findings demonstrate that boar spermatozoa undergoing cryopreservation can withstand rapid cooling rates before freezing.

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Influence of cooling rate on Saccharomyces cerevisiae destruction during freezing: unexpected viability at ultra-rapid cooling rates

Cryobiology ◽

10.1016/s0011-2240(02)00161-x ◽

2003 ◽

Vol 46 (1) ◽

pp. 33-42 ◽

Cited By ~ 40

Author(s):

Frédéric Dumont ◽

Pierre-André Marechal ◽

Patrick Gervais

Keyword(s):

Saccharomyces Cerevisiae ◽

Cooling Rate ◽

Cooling Rates ◽

Rapid Cooling

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Determination of Eutectoid Transformation Temperatures in Ductile Cast Iron

Archives of Foundry Engineering ◽

10.1515/afe-2015-0078 ◽

2015 ◽

Vol 15 (4) ◽

pp. 51-54 ◽

Cited By ~ 1

Author(s):

A.W. Orłowicz ◽

A. Trytek ◽

M. Mróz ◽

M. Tupaj

Keyword(s):

Cast Iron ◽

Cooling Rate ◽

Ductile Cast Iron ◽

Eutectoid Transformation ◽

Heating Rates ◽

Cooling Rates ◽

Metallographic Examination ◽

Transformation Temperatures ◽

Rate Of Cooling

Abstract The paper proposes a methodology useful in verification of results of dilatometric tests aimed at determination of temperatures defining the start and the end of eutectoid transformation in the course of ductile cast iron cooling, based on quenching techniques and metallographic examination. For an industrial melt of ductile cast iron, the effect of the rate of cooling after austenitization at temperature 900°C carried out for 30 minutes on temperatures TAr1start and TAr1end was determined. The heating rates applied in the study were the same as the cooling rates and equaled 30, 60, 90, 150, and 300°C/h. It has been found that with increasing cooling rate, values of temperatures TAr1start and TAr1end decrease by several dozen degrees.

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Sex-Specific Long-Term Trends in Length of Hospital Stay, Postmenstrual Age at Discharge, and Survival in Very Low Birth Weight Infants

Neonatology ◽

10.1159/000515899 ◽

2021 ◽

pp. 1-9

Author(s):

Matthias Fröhlich ◽

Tatjana Tissen-Diabaté ◽

Christoph Bührer ◽

Stephanie Roll

Keyword(s):

Birth Weight ◽

Low Birth Weight ◽

Hospital Stay ◽

Very Low Birth Weight ◽

Survival Rates ◽

Length Of Hospital Stay ◽

Mortality Rates ◽

Vlbw Infants ◽

Postmenstrual Age ◽

Over Time

Introduction: In very low birth weight (<1,500 g, VLBW) infants, morbidity and mortality have decreased substantially during the past decades, and both are known to be lower in girls than in boys. In this study, we assessed sex-specific changes over time in length of hospital stay (LOHS) and postmenstrual age at discharge (PAD), in addition to survival in VLBW infants. Methods: This is a single-center retrospective cohort analysis based on quality assurance data of VLBW infants born from 1978 to 2018. Estimation of sex-specific LOHS over time was based on infants discharged home from neonatal care or deceased. Estimation of sex-specific PAD over time was based on infants discharged home exclusively. Analysis of in-hospital survival was performed for all VLBW infants. Results: In 4,336 of 4,499 VLBW infants admitted from 1978 to 2018 with complete data (96.4%), survival rates improved between 1978–1982 and 1993–1997 (70.8 vs. 88.3%; hazard ratio (HR) 0.20, 95% confidence interval 0.14, 0.30) and remained stable thereafter. Boys had consistently higher mortality rates than girls (15 vs. 12%, HR 1.23 [1.05, 1.45]). Nonsurviving boys died later compared to nonsurviving girls (adjusted mean survival time 23.0 [18.0, 27.9] vs. 20.7 [15.0, 26.3] days). LOHS and PAD assessed in 3,166 survivors displayed a continuous decrease over time (1978–1982 vs. 2013–2018: LOHS days 82.9 [79.3, 86.5] vs. 60.3 [58.4, 62.1] days); PAD 40.4 (39.9, 40.9) vs. 37.4 [37.1, 37.6] weeks). Girls had shorter LOHS than boys (69.4 [68.0, 70.8] vs. 73.0 [71.6, 74.4] days) and were discharged with lower PAD (38.6 [38.4, 38.8] vs. 39.2 [39.0, 39.4] weeks). Discussion/Conclusions: LOHS and PAD decreased over the last 40 years, while survival rates improved. Male sex was associated with longer LOHS, higher PAD, and higher mortality rates.

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Community characteristics of forest understory birds along an elevational gradient in the Horn of Africa: A multi-year baseline

The Condor ◽

10.1093/ornithapp/duab009 ◽

2021 ◽

Author(s):

Kyle D Kittelberger ◽

Montague H C Neate-Clegg ◽

Evan R Buechley ◽

Çağan Hakkı Şekercioğlu

Keyword(s):

Species Richness ◽

Species Turnover ◽

Survival Rates ◽

Elevational Gradient ◽

Forest Understory ◽

Bird Abundance ◽

Tropical Mountains ◽

Demographic Rates ◽

Understory Birds ◽

Over Time

Abstract Tropical mountains are global hotspots for birdlife. However, there is a dearth of baseline avifaunal data along elevational gradients, particularly in Africa, limiting our ability to observe and assess changes over time in tropical montane avian communities. In this study, we undertook a multi-year assessment of understory birds along a 1,750 m elevational gradient (1,430–3,186 m) in an Afrotropical moist evergreen montane forest within Ethiopia’s Bale Mountains. Analyzing 6 years of systematic bird-banding data from 5 sites, we describe the patterns of species richness, abundance, community composition, and demographic rates over space and time. We found bimodal patterns in observed and estimated species richness across the elevational gradient (peaking at 1,430 and 2,388 m), although no sites reached asymptotic species richness throughout the study. Species turnover was high across the gradient, though forested sites at mid-elevations resembled each other in species composition. We found significant variation across sites in bird abundance in some of the dietary and habitat guilds. However, we did not find any significant trends in species richness or guild abundances over time. For the majority of analyzed species, capture rates did not change over time and there were no changes in species’ mean elevations. Population growth rates, recruitment rates, and apparent survival rates averaged 1.02, 0.52, and 0.51 respectively, and there were no elevational patterns in demographic rates. This study establishes a multi-year baseline for Afrotropical birds along an elevational gradient in an under-studied international biodiversity hotspot. These data will be critical in assessing the long-term responses of tropical montane birdlife to climate change and habitat degradation.

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The effect of cooling rate on crystallization behavior and tensile properties of CF/PEEK composites

Journal of Polymer Engineering ◽

10.1515/polyeng-2020-0356 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Guangming Dai ◽

Lihua Zhan ◽

Chenglong Guan ◽

Minghui Huang

Keyword(s):

Cooling Rate ◽

Crystallization Temperature ◽

Crystallization Behavior ◽

Crystalline Polymer ◽

Scanning Calorimetry ◽

Nonisothermal Crystallization ◽

Cooling Rates ◽

Control Range ◽

Temperature Range ◽

Transverse Tensile

Abstract In this study, the differential scanning calorimetry (DSC) tests were performed to measure the nonisothermal crystallization behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites under different cooling rates. The characteristic parameters of crystallization were obtained, and the nonisothermal crystallization model was established. The crystallization temperature range of the material at different cooling rates was predicted by the model. The unidirectional laminates were fabricated at different cooling rates in the crystallization temperature range. The results showed that the crystallization temperature range shifted to a lower temperature with the increase of cooling rate, the established nonisothermal crystallization model was consistent with the DSC test results. It is feasible to shorten the cooling control range from the whole process to the crystallization range. The crystallinity and transverse tensile strength declined significantly with the increase of the cooling rate in the crystallization temperature range. The research results provided theoretical support for the selection of cooling conditions and temperature control range, which could be applied to the thermoforming process of semi-crystalline polymer matrixed composites to improve the manufacturing efficiency.

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Effects of RE on Critical Cooling Rate of Bearing-B Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.761 ◽

2012 ◽

Vol 535-537 ◽

pp. 761-763 ◽

Cited By ~ 1

Author(s):

Yi Sheng Zhao ◽

Xin Ming Zhang ◽

Zhi Guo Gao

Keyword(s):

Phase Change ◽

Cooling Rate ◽

Experimental Results ◽

Cooling Rates ◽

Critical Cooling Rate ◽

The Law

The law of phase change of bearing-B steel during continual cooling was studied by adopting dilatometer. The CCT curves of bearing-B steel were drawn, and the effects of RE on critical cooling rates were studied. The experimental results show that the start temperatures of martensite TM was decreased from 438 to 404°C. The critical cooling rate was simultaneously decreased from 33 to 15°C/s.

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Theoretical Aspccts of Cloud Drop Distributions

Australian Journal of Chemistry ◽

10.1071/ch9490376 ◽

1949 ◽

Vol 2 (3) ◽

pp. 376 ◽

Cited By ~ 3

Author(s):

EB Kraus ◽

B Smith

Keyword(s):

Cooling Rate ◽

Drop Size ◽

Initial Temperature ◽

Theoretical Study ◽

Air Pressure ◽

Size Spectrum ◽

Condensation Nuclei ◽

Cloud Drop ◽

Rate Of Cooling

A theoretical study indicates that the number and size of the drops formed in a cloud vary with the rate of cooling, the initial temperature, and the air pressure. The faster the cooling rate, the lower the initial temperature, and the lower the altitude, the greater is the number of drops and the smaller their size. The drop size spectrum also depends, to a large extent, on the number of available condensation nuclei. Furthermore, it tends to be widened by sedimentation and turbulence.

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