scholarly journals Segregated water observed in a putative fish embryo cryopreservative

2016 ◽  
Vol 3 (3) ◽  
pp. 150655 ◽  
Author(s):  
O. Kirichek ◽  
A. K. Soper ◽  
B. Dzyuba ◽  
W. V. Holt
Keyword(s):  
Endangered Species ◽  
Computer Modelling ◽  
Water Structure ◽  
Ice Formation ◽  
Critical Property ◽  
Cooling Process ◽  
Fish Embryo ◽  
Surrounding Matrix ◽  
Quench Cooling ◽  
Conservation Of Endangered Species

Development of new cryopreservation strategies has major potential in medicine and agriculture and is critical to the conservation of endangered species that currently cannot be preserved. A critical property of any potential cryopreservative solution is its ability to prevent cell-damaging ice formation during cooling and subsequent heating. This study focuses on the freezing behaviour of promising model cryoprotective solutions. We perform neutron scattering analysis, combined with computer modelling, of the water structure after quench cooling these solutions. It is found that water in this solution forms nano-clusters encapsulated by the surrounding matrix of cryoprotectant solute molecules. We posit that these small volumes inhibit ice formation, because water does not have space for the structural relaxation required to crystallize on the timescale of the cooling process.

Numerical Simulation of Immersion Quench Cooling Process: Part I

2008 ◽  
Author(s):  
Vedanth Srinivasan ◽  
Kil-min Moon ◽  
David Greif ◽  
DeMing Wang ◽  
Myung-hwan Kim
Keyword(s):  
Phase Change ◽  
Nucleate Boiling ◽  
Vapor Flow ◽  
Cooling Process ◽  
Change Models ◽  
Liquid Domain ◽  
Commercial Code ◽  
Quenching Process ◽  
Solid Part ◽  
Quench Cooling

In this article, we describe a newly developed modeling procedure to simulate the immersion quench cooling process using the commercial code AVL-FIRE. The boiling phase change process, triggered by the dipping hot solid part into a subcooled liquid bath and the ensuing two-phase flow is handled using an Eulerian two-fluid method. Mass transfer effects are modeled based on different boiling modes such as film or nucleate boiling regime prevalent in the system. Separate computational domains constructed for the quenched solid part and the liquid (quenchant) domain are numerically coupled at the interface of the solid-liquid boundaries using the AVL-Code-Coupling-Interface (ACCI) feature. The advanced ACCI procedure allows the information pertaining to the phase change rates in the liquid domain to appear as cooling rates on the quenched solid boundaries. As a consequence, the code handles the multiphase flow dynamics in the liquid domain in conjunction with the temperature evolution in the solid region in a tightly coupled fashion. The methodology, implemented in the commercial code AVL-FIRE, is exercised in simulating the quenching of solid parts. In part I of the present research, phase change models are validated by simulating a work piece quenching process for which measurement data are available for various water temperature ranging from 20C to 80C. The computations provide a detailed description of the vapor and temperature fields in the liquid and solid domain at various time instants. In particular, the modifications arising in the liquid-vapor flow field in the near vicinity of the solid interface as a function of the boiling mode is well accommodated. The temperature history predicted by our model at different monitoring points, under different subcooling conditions, correlate very well with the experimental data wherever available. In part II, the model is further applied to real engine cylinder head quenching process and assessment is made for the cooling curves for various measuring points. Overall, the predictive capability of the new quenching model is well demonstrated.

Effects of lead width variation, re-freezing and mixing events on lead water structure in the central Arctic

2021 ◽  
Author(s):  
Daiki Nomura ◽  
Alison Web ◽  
Yuhong Li ◽  
Manuel Dall’osto ◽  
Katrin Schmidt ◽  
...  
Keyword(s):  
Vertical Structure ◽  
Lower Boundary ◽  
Water Structure ◽  
Sampling Period ◽  
Ice Formation ◽  
Layer Surface ◽  
Mixing Process ◽  
Survey Period ◽  
Mixing Processes ◽  
Surface Ice

<p>We undertook a lead survey during the international drift campaign MOSAiC, Leg 5 (from 22 August to 17 September 2020) to understand the effects of lead width variation, re-freezing, and mixing events on lead water vertical structure. At the beginning of the survey period, the freshwater layer was occupied for the top 1 m depth and there were strong vertical gradients in temperature, salinity, and dissolved oxygen (DO) within 1 m depth: from 0.0°C to –1.6°C for temperature, from 0.0 to 31.4 psu for salinity, and 10.5 to 13.5 mg L<sup>–1</sup> for DO. A strong DO minimum layer corresponded with a salinity of 25 psu, and usually occurred at the freshwater–seawater interface at approx. 1 m depth, most likely as a result of an accumulation of organic matter and ongoing degradation/respiration processes at this interface. However, during the survey period, these strong gradients weakened and reduced the freshwater layer thickness (FLT). In the first half of the sampling period (until 4 September), FLT changed due to variations in lead width: as lead width increased, FLT decreased due to a stretching of the freshwater layer. In the second half of the sampling period, FLT was controlled by the surface ice formation (re-freezing) and mixing processes along the lower boundary of the freshwater layer. Surface ice formation removed freshwater and the formation of surface ice (about 0.2 m thick) explains 20% of the reduction of FLT. The remaining 80% of the reduction of FLT was due to the mixing process within the water column that was initiated by cooling and re-freezing. This mixing process diluted the salinity from 31.6 to 29.3 psu in the water below freshwater layer towards the end of the survey period. Our results indicate that lead water structure can change rapidly and dynamically and that this has significant effects on the biogeochemical exchange between lead systems and the atmosphere.</p>

scholarly journals Prioritizing recovery funding to maximize conservation of endangered species

2018 ◽  
Vol 11 (6) ◽  
pp. e12604 ◽  
Author(s):  
Tara G. Martin ◽  
Laura Kehoe ◽  
Chrystal Mantyka-Pringle ◽  
Iadine Chades ◽  
Scott Wilson ◽  
...  
Keyword(s):  
Endangered Species ◽  
Conservation Of Endangered Species

Cryopreservation of orchid mycorrhizal fungi: A tool for the conservation of endangered species

2013 ◽  
Vol 93 (2) ◽  
pp. 134-137 ◽  
Author(s):  
Enrico Ercole ◽  
Michele Rodda ◽  
Matteo Molinatti ◽  
Samuele Voyron ◽  
Silvia Perotto ◽  
...  
Keyword(s):  
Endangered Species ◽  
Mycorrhizal Fungi ◽  
Orchid Mycorrhizal Fungi ◽  
Conservation Of Endangered Species
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