The effect of equilibration time on desorption rate measurements with chlorinated alkenes and aquifer particles

1994 ◽  
Vol 13 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Thomas C. Harmon ◽  
Paul V. Roberts
Author(s):  
Amina Kumarovna Karamuldaeva ◽  
Andrey Mikhailovich Tikhomirov

The article studies the possibility to use glycerol as cryoprotectant, instead of dimethylsulfoxide for cryopreservation of sperm of inconnu ( Stenodus leucichthys Gueldenstaedtii, 1772). Investigations were carried out from 2015 to 2016 in the laboratory of the Southern Scientific Center, Russian Academy of Sciences, on the basis of the Astrakhan State Technical University. The material collected on the Alexander sturgeon hatcheries (the Astrakhan region) in the spawning period. Native sperm of 6 male inconnu species was used as a control means. The semen quality was determined in terms of moving activity (life time) of sperm after its activation by water. As the cryoprotectant there were used: base solution - 80%, sucrose - 1.71 g/l, mannite - 0.98 g/l, yolk - 10%, dimethylsulfoxide - 10% and base solution - 87%, sucrose - 1.71% g/l, mannite - 0.98 g/l, yolk - 10%, glycerol - 3 variants: 3; 5 and 10%. In order to provide the most complete penetration of cryoprotectants into the cells there were used electrostimulation of cell membranes. Equilibration time was 5 and 15 minutes. Thawing semen was performed in a water bath at a temperature of 38-40°C. For removing protectors from cells there was chosen a saline solution (0.7% NaCl) as isotonic solution. In tests using dimethylsulfoxide life activity of sex cells was 2 times lower than in tests with glycerol: 78 and 186.2 s at the end of equilibration and 52.3 and 128.9 s after thawing. Sperm showed maximum activity under 5% glycerol concentration during equilibration - 15 min. Concentration of 3% was insufficient, concentration of 10% was excessive, as it suppressed activity of sperm. Egg yolk which coagulated together with glycerol, making difficulty for observing, had to be excluded from the composition of cryoprotectant.


2010 ◽  
Vol 7 (1) ◽  
Author(s):  
Saraswati Prabawardani

<!--[if gte mso 9]><xml> <w:WordDocument> <w:View>Normal</w:View> <w:Zoom>0</w:Zoom> <w:PunctuationKerning /> <w:ValidateAgainstSchemas /> <w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid> <w:IgnoreMixedContent>false</w:IgnoreMixedContent> <w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText> <w:Compatibility> <w:BreakWrappedTables /> <w:SnapToGridInCell /> <w:WrapTextWithPunct /> <w:UseAsianBreakRules /> <w:DontGrowAutofit /> <w:UseFELayout /> </w:Compatibility> <w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel> </w:WordDocument> </xml><![endif]--><!--[if gte mso 9]><xml> <w:LatentStyles DefLockedState="false" LatentStyleCount="156"> </w:LatentStyles> </xml><![endif]--> <!--[if gte mso 10]> <mce:style><! /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman"; mso-fareast-font-family:"Times New Roman"; mso-ansi-language:#0400; mso-fareast-language:#0400; mso-bidi-language:#0400;} --> <!--[endif]--> <p class="MsoNormal" style="text-align: justify;"><span style="font-size: 10pt;">The measurement of plant water status such as leaf water potential (LWP) and leaf relative water content (RWC) is important part of understanding plant physiology and biomass production. Preliminary study was made to determine the optimum amount of leaf abrasion and equilibration time of sweet potato leaf inside the thermocouple psychrometer chambers. Based on the trial, the standard equilibration time curve of a Peltier thermocouple for sweet potato leaf was between 2 and 3 hours. To increase the water vapour conductance across the leaf epidermis the waxy leaf cuticle should be removed or broken by abrasion. The result showed that 4 times leaf rubbings was accepted as the most effective way to increase leaf vapour conductance of sweet potato in the psychrometer chambers. In calculating the leaf relative water content, unstressed water of sweet potato leaves require 4 hours imbibition, whereas water stressed of sweet potato leaves require 5 to 6 hours to reach the saturation time. Either leaf water potential or relative water content can be used as a parameter for plant water status in sweet potato.</span><span style="font-size: 10pt;"> </span></p>


1993 ◽  
Vol 70 (10) ◽  
pp. 832-838 ◽  
Author(s):  
JOSEPH E. LAVAUX ◽  
W DIANE KELLER
Keyword(s):  
Dry Eye ◽  

2021 ◽  
Vol 144 ◽  
pp. 106438
Author(s):  
Sonya Barzgar ◽  
Mohamed Tarik ◽  
Christian Ludwig ◽  
Barbara Lothenbach
Keyword(s):  

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3612
Author(s):  
Marinos Xagoraris ◽  
Alexandra Skouria ◽  
Panagiota-Kyriaki Revelou ◽  
Eleftherios Alissandrakis ◽  
Petros A. Tarantilis ◽  
...  

This study aimed at an experimental design of response surface methodology (RSM) in the optimization of the dominant volatile fraction of Greek thyme honey using solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). For this purpose, a multiple response optimization was employed using desirability functions, which demand a search for optimal conditions for a set of responses simultaneously. A test set of eighty thyme honey samples were analyzed under the optimum conditions for validation of the proposed model. The optimized combination of isolation conditions was the temperature (60 °C), equilibration time (15 min), extraction time (30 min), magnetic stirrer speed (700 rpm), sample volume (6 mL), water: honey ratio (1:3 v/w) with total desirability over 0.50. It was found that the magnetic stirrer speed, which has not been evaluated before, had a positive effect, especially in combination with other factors. The above-developed methodology proved to be effective in the optimization of isolation of specific volatile compounds from a difficult matrix, like honey. This study could be a good basis for the development of novel RSM for other monofloral honey samples.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Heres ◽  
J. Troncoso ◽  
E. Paredes

AbstractCryopreservation is the only reliable method for long-term storage of biological material that guarantees genetic stability. This technique can be extremely useful for the conservation of endangered species and restock natural populations for declining species. Many factors have negatively affected the populations of high economical value shellfish in Spain and, as a result, many are declining or threatened nowadays. This study was focused on early-life stages of Venerupis corrugata, Ruditapes decussatus and Ruditapes philippinarum to develop successful protocols to enhance the conservation effort and sustainable shellfishery resources. Firstly, common cryoprotecting agents (CPAs) were tested to select the suitable permeable CPA attending to toxicity. Cryopreservation success using different combinations of CPA solutions, increasing equilibrium times and larval stages was evaluated attending to survival and shell growth at 2 days post-thawing. Older clam development stages were more tolerant to CPA toxicity, being ethylene-glycol (EG) and Propylene-glycol (PG) the least toxic CPAs. CPA solution containing EG yielded the highest post-thawing survival rate and the increase of equilibration time was not beneficial for clam larvae. Cryopreservation of trochophores yielded around 50% survivorship, whereas over 80% of cryopreserved D-larvae were able to recover after thawing.


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