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Sample records for serum freezing point

  1. A Determination of the Ratio of the Zinc Freezing Point to the Tin Freezing Point by Noise Thermometry

    Science.gov (United States)

    Labenski, J. R.; Tew, W. L.; Benz, S. P.; Nam, S. W.; Dresselhaus, P.

    2008-02-01

    A Johnson-noise thermometer (JNT) has been used with a quantized voltage noise source (QVNS), as a calculable reference to determine the ratio of temperatures near the Zn freezing point to those near the Sn freezing point. The temperatures are derived in a series of separate measurements comparing the synthesized noise power from the QVNS with that of Johnson noise from a known resistance. The synthesized noise power is digitally programed to match the thermal noise powers at both temperatures and provides the principle means of scaling the temperatures. This produces a relatively flat spectrum for the ratio of spectral noise densities, which is close to unity in the low-frequency limit. The data are analyzed as relative spectral ratios over the 4.8 to 450 kHz range averaged over a 3.2 kHz bandwidth. A three-parameter model is used to account for differences in time constants that are inherently temperature dependent. A drift effect of approximately -6 μK·K-1 per day is observed in the results, and an empirical correction is applied to yield a relative difference in temperature ratios of -11.5 ± 43 μK·K-1 with respect to the ratio of temperatures assigned on the International Temperature Scale of 1990 (ITS-90). When these noise thermometry results are combined with results from acoustic gas thermometry at temperatures near the Sn freezing point, a value of T - T 90 = 7 ± 30 mK for the Zn freezing point is derived.

  2. Effect of haemolysis and repeated freeze-thawing cycles on wild boar serum antibody testing by ELISA

    Directory of Open Access Journals (Sweden)

    Boadella Mariana

    2011-11-01

    Full Text Available Abstract Background Monitoring wildlife diseases is needed to identify changes in disease occurrence. Wildlife blood samples are valuable for this purpose but are often gathered haemolysed. To maximise information, sera often go through repeated analysis and freeze-thaw cycles. Herein, we used samples of clean and haemolysed Eurasian wild boar (Sus scrofa serum stored at -20°C and thawed up to five times to study the effects of both treatments on the outcome of a commercial ELISA test for the detection of antibodies against Suid Herpesvirus 1 (ADV. Results The estimated prevalence of antibodies against ADV was 50-53% for clean and haemolysed sera. Hence, haemolysis did not reduce the mean observed serum antibody prevalence. However, 10 samples changed their classification after repeated freeze-thawing. This included 3 (15% of the clean sera and 7 (41% of the haemolysed sera. Conclusions We recommend (1 establishing more restrictive cut-off values when testing wildlife sera, (2 recording serum quality prior to sample banking, (3 recording the number of freezing-thawing cycles and (4 store sera in various aliquots to reduce repeated usage. For instance, sera with more than 3 freeze-thaw cycles and a haemolysis of over 3 on a scale of 4 should better be discarded for serum antibody monitoring. Even clean (almost not haemolysed sera should not go through more than 5 freeze-thaw cycles.

  3. The freezing point of raw and heat treated sheep milk and its variation during lactation

    Directory of Open Access Journals (Sweden)

    Bohumíra Janštová

    2013-01-01

    Full Text Available The freezing point of milk is an important indicator of the adulteration of the milk with water, but heat treatment may also affect its value. The aim of this study was determine freezing point of raw and heat treated sheep milk and its variation during lactation. The freezing point was determined in 42 bulk tank raw sheep milk samples and 42 pasteurized milk samples collected during lactation of sheep at one ecofarm in Moravian Walachia (Valašsko in the Czech Republic. The freezing point was determined in accordance with the standard ČSN 57 0538 using a thermistor cryoscope. The average freezing point of raw milk was -0.617 ± 0.052 °C, with a range from -0.560 to -0.875 °C. The freezing point was lower in the first months of lactation and increased at the end of lactation. The freezing point correlated (r = 0.8967 with the content of total non-fat solids. The average freezing point of sheep milk pasteurized at 65 °C for 30 min was -0.614 ± 0.053 °C, with a range from -0.564 to -0.702 °C. The median of freezing point differences between raw and pasteurized milk was 0.004 °C. Our study extends data about physico-chemical properties of sheep milk and registers for the first time specific changes in the freezing point value of sheep milk by heating.

  4. Production of Low-Freezing-Point Highly Branched Alkanes through Michael Addition.

    Science.gov (United States)

    Jing, Yaxuan; Xia, Qineng; Liu, Xiaohui; Wang, Yanqin

    2017-12-22

    A new approach for the production of low-freezing-point, high-quality fuels from lignocellulose-derived molecules was developed with Michael addition as the key step. Among the investigated catalysts, CoCl 2 ⋅6 H 2 O was found most active for the Michael addition of 2,4-pentanedione with FA (single aldol adduct of furfural and acetone, 4-(2-furanyl)-3-butene-2-one). Over CoCl 2 ⋅6 H 2 O, a high carbon yield of C 13 oxygenates (about 75 %) can be achieved under mild conditions (353 K, 20 h). After hydrodeoxygenation, low-freezing-point (hydrodeoxygenation, high density (0.8415 g mL -1 ) and low-freezing-point (<223 K) branched alkanes with 18, 23 carbons within lubricant range were also obtained over a Pd/NbOPO 4 catalyst. These highly branched alkanes can be directly used as transportation fuels or additives. This work opens a new strategy for the synthesis of highly branched alkanes with low freezing point from renewable biomass. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Estimation of Freezing Point of Hydrocarbon and Hydrofluorocarbon Mixtures for Mixed Refrigerant jt Cryocooler

    Science.gov (United States)

    Hwang, G.; Lee, J.; Jeong, S.

    2010-04-01

    Estimating the freezing point of refrigerant is an essential part in designing an MR JT (Mixed refrigerant Joule-Thomson) cryocooler to prevent itself from clogging and to operate with stability. There were researches on estimating freezing point, but some of them resulted in the wrong prediction of clogging. In this paper, the freezing point of the MR is precisely estimated with caution of clogging. The solubility of HC (hydrocarbon) and HFC (hydrofluorocarbon) mixture components are obtained with their activity coefficients, which represent the molecular interaction among the components. The freezing points of the MR JT cryocooler are systematically investigated in the operating temperature range from 70 K to 90 K.

  6. An Equipment to Measure the Freezing Point of Soils under Higher Pressure

    Science.gov (United States)

    Wang, Dayan; Guan, Hui; Wen, Zhi; Ma, Wei

    2014-05-01

    Soil freezing point is the highest temperature at which ice can be presented in the system and soil can be referred to as frozen. The freezing temperature of soil is an important parameter for solving many practical problems in civil engineering, such as evaluation of soil freezing depth, prediction of soil heaving, force of soil suction, etc. However, as the freezing temperature is always affected by many factors like soil particle size, mineral composition, water content and the external pressure endured by soils, to measure soil freezing point is a rather difficult task until now, not to mention the soil suffering higher pressure. But recently, with the artificial freezing technology widely used in the excavation of deep underground space, the frozen wall thickness is a key factor to impact the security and stability of deep frozen wall. To determine the freeze wall thickness, the location of the freezing front must be determined firstly, which will deal with the determination of the soil freezing temperature. So how to measure the freezing temperature of soil suffering higher pressure is an important problem to be solved. This paper will introduce an equipment which was developed lately by State Key Laboratory of Frozen Soil Engineering to measure the freezing-point of soils under higher pressure. The equipment is consisted of cooling and keeping temperature system, temperature sensor and data collection system. By cooling and keeping temperature system, not only can we make the higher pressure soil sample's temperature drop to a discretionary minus temperature, but also keep it and reduce the heat exchange of soil sample with the outside. The temperature sensor is the key part to our measurement, which is featured by high precision and high sensitivity, what is more important is that the temperature sensor can work in a higher pressure condition. Moreover, the major benefit of this equipment is that the soil specimen's loads can be loaded by any microcomputer

  7. Freezing Point Determination of Water–Ionic Liquid Mixtures

    DEFF Research Database (Denmark)

    Liu, Yanrong; Meyer, Anne S.; Nie, Yi

    2017-01-01

    .841 K in thefirst system and at a water mole fraction of 0.657 and 202.565 K inthe second system. Water activities in aqueous IL solutions were predictedby COSMO-RS and COSMO-SAC and compared to water activities derivedfrom the experimentally determined freezing points. The COSMO-RS predictionswere...... closer to the experimental water activities than the COSMO-SACpredictions. The experimental results indicate that the freezing pointsof IL+H2O systems are affected by the nature of both cationsand anions. However, according to the COSMO-RS excess enthalpy predictionresults, the anions have a relatively...

  8. Realization of the Temperature Scale in the Range from 234.3 K (Hg Triple Point) to 1084.62°C (Cu Freezing Point) in Croatia

    Science.gov (United States)

    Zvizdic, Davor; Veliki, Tomislav; Grgec Bermanec, Lovorka

    2008-06-01

    This article describes the realization of the International Temperature Scale in the range from 234.3 K (mercury triple point) to 1084.62°C (copper freezing point) at the Laboratory for Process Measurement (LPM), Faculty of Mechanical Engineering and Naval Architecture (FSB), University of Zagreb. The system for the realization of the ITS-90 consists of the sealed fixed-point cells (mercury triple point, water triple point and gallium melting point) and the apparatus designed for the optimal realization of open fixed-point cells which include the gallium melting point, tin freezing point, zinc freezing point, aluminum freezing point, and copper freezing point. The maintenance of the open fixed-point cells is described, including the system for filling the cells with pure argon and for maintaining the pressure during the realization.

  9. Impact of Heat Treatment on the Freezing Points of Cow and Goat Milk

    Directory of Open Access Journals (Sweden)

    Bohumíra Janštová

    2009-01-01

    Full Text Available The aim of this study was to monitor the impact of heat treatment variables on the freezing point of cow and goat milk. The freezing point (FP was established in 30 bulk tank samples of goat milk and in 30 bulk tank samples of cow milk which were subject to laboratory heat treatment at temperatures of 72 °C (A, 85 °C (B, 95 °C (C, with the same exposition times of 20 s. Freezing point measurements of raw and heat-treated milk were carried out in compliance with the Standard CTS 57 0538 by a thermistor cryoscope. The FP of raw cow milk increased with heat treatment from the initial values of -0.5252 ± 0.0114 °C (O by 0.0023 °C (A, 0.0034 °C (B and 0.0051°C (C. Changes in FP values of goat milk were detected, from its initial value of –0.5530 ± 0.0086 °C there was an increase in the FP depending on the mode of heat treatment due to pasteurization by an average of 0.0028 °C (A, 0.0036 °C (B and 0.0054 °C (C. The dynamics of the changes were similar both in goat and cow milk. Freezing point values in cow and goat milk differed (P ⪬ 0.01 when compared to the freezing point of untreated milk after the individual interventions as well as when compared between each other. An increase in the heat treatment temperature of cow and goat milk causes an increase in the freezing point (a shift towards zero. These results can be used in practice for checking the raw material in dairy industry.

  10. Freezing Point Depressions of Phase Change CO2 Solvents

    DEFF Research Database (Denmark)

    Arshad, Muhammad Waseem; Fosbøl, Philip Loldrup; von Solms, Nicolas

    2013-01-01

    Freezing point depressions (FPD) in phase change solvents containing 2-(diethylamino)ethanol (DEEA) and 3-(methylamino)propylamine (MAPA) were measured using a modified Beckmann apparatus. The measurements were performed for the binary aqueous DEEA and MAPA solutions, respectively...

  11. Open Zinc Freezing-Point Cell Assembly and Evaluation

    Science.gov (United States)

    Žužek, V.; Batagelj, V.; Drnovšek, J.; Bojkovski, J.

    2014-07-01

    An open metal freezing-point cell design has been developed in the Laboratory of Metrology and Quality. According to our design, a zinc cell was successfully assembled. The paper presents the needed parts for the cell, the cleaning process, and sealing of the cell. The assembled cell was then evaluated by comparison with two commercial closed zinc cells of different manufacturers. The freezing plateaus of the cells were measured, and a direct cell comparison was made. It was shown that the assembled open cell performed better than the used closed cell and was close to the brand new closed cell. The nominal purity of the zinc used for the open cell was 7 N, but the freezing plateau measurement suggests a higher impurity concentration. It was assumed that the zinc was contaminated to some extent during the process of cutting as its original shape was an irregular cylinder. The uncertainty due to impurities for the assembled cell is estimated to be 0.3 mK. Furthermore, the immersion profile and the pressure coefficient were measured. Both results are close to their theoretical values.

  12. Design and evaluation of aircraft heat source systems for use with high-freezing point fuels

    Science.gov (United States)

    Pasion, A. J.

    1979-01-01

    The objectives were the design, performance and economic analyses of practical aircraft fuel heating systems that would permit the use of high freezing-point fuels on long-range aircraft. Two hypothetical hydrocarbon fuels with freezing points of -29 C and -18 C were used to represent the variation from current day jet fuels. A Boeing 747-200 with JT9D-7/7A engines was used as the baseline aircraft. A 9300 Km mission was used as the mission length from which the heat requirements to maintain the fuel above its freezing point was based.

  13. Freezing Point Depressions of Aqueous MEA, MDEA, and MEA−MDEA Measured with a New Apparatus

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Pedersen, Mikkel Gielsager; Thomsen, Kaj

    2011-01-01

    Freezing points for aqueous monoethanolamine (MEA), methyl diethanolamine (MDEA), and MEA−MDEA solutions were measured in the concentration range from 0 to 0.4 mass fractions of the alkanolamines. For the aqueous MEA−MDEA system, freezing points for 1:4, 1:2, 1:1, 2:1, and 4:1 molar ratios of MEA....../MDEA were determined. The experimental values indicate that the MDEA−water interaction is stronger than the MEA−water interaction. Measurements were carried out by a new modified Beckmann apparatus, which has not previously been described. The apparatus and method proved to have good repeatability...

  14. Well-plate freeze-drying

    DEFF Research Database (Denmark)

    Trnka, Hjalte; Rantanen, Jukka; Grohganz, Holger

    2015-01-01

    Abstract Context: Freeze-drying in presence of excipients is a common practice to stabilize biomacromolecular formulations. The composition of this formulation is known to affect the quality of the final product. Objective: The aim of this study was to evaluate freeze-drying in well-plates as a h......Abstract Context: Freeze-drying in presence of excipients is a common practice to stabilize biomacromolecular formulations. The composition of this formulation is known to affect the quality of the final product. Objective: The aim of this study was to evaluate freeze-drying in well......-plates as a high throughput platform for formulation screening of freeze-dried products. Methods: Model formulations consisting of mannitol, sucrose and bovine serum albumin were freeze-dried in brass well plates, plastic well plates and vials. Physical properties investigated were solid form, residual moisture......, cake collapse and reconstitution time. Results: Samples freeze-dried in well-plates had an acceptable visual cake appearance. Solid form analysis by high throughput X-ray powder diffraction indicated comparable polymorphic outcome independent of the container. The expected increase in moisture level...

  15. Oxygen demand of aircraft and airfield pavement deicers and alternative freezing point depressants

    Science.gov (United States)

    Corsi, Steven R.; Mericas, Dean; Bowman, George

    2012-01-01

    Aircraft and pavement deicing formulations and other potential freezing point depressants were tested for biochemical oxygen demand (BOD) and chemical oxygen demand (COD). Propylene glycol-based aircraft deicers exhibited greater BOD5 than ethylene glycol-based aircraft deicers, and ethylene glycol-based products had lower degradation rates than propylene glycol-based products. Sodium formate pavement deicers had lower COD than acetate-based pavement deicers. The BOD and COD results for acetate-based pavement deicers (PDMs) were consistently lower than those for aircraft deicers, but degradation rates were greater in the acetate-based PDM than in aircraft deicers. In a 40-day testing of aircraft and pavement deicers, BOD results at 20°C (standard) were consistently greater than the results from 5°C (low) tests. The degree of difference between standard and low temperature BOD results varied among tested products. Freshwater BOD test results were not substantially different from marine water tests at 20°C, but glycols degraded slower in marine water than in fresh water for low temperature tests. Acetate-based products had greater percentage degradation than glycols at both temperatures. An additive component of the sodium formate pavement deicer exhibited toxicity to the microorganisms, so BOD testing did not work properly for this formulation. BOD testing of alternative freezing point depressants worked well for some, there was little response for some, and for others there was a lag in response while microorganisms acclimated to the freezing point depressant as a food source. Where the traditional BOD5 test performed adequately, values ranged from 251 to 1,580 g/kg. Where the modified test performed adequately, values of BOD28 ranged from 242 to 1,540 g/kg.

  16. Predicting the initial freezing point and water activity of meat products from composition data

    NARCIS (Netherlands)

    Sman, van der R.G.M.; Boer, E.P.J.

    2005-01-01

    In this paper we predict the water activity and initial freezing point of food products (meat and fish) based on their composition. The prediction is based on thermodynamics (the Clausius-Clapeyron equation, the Ross equation and an approximation of the Pitzer equation). Furthermore, we have taken

  17. Freezing point osmometry of milk to determine the additional water content – an issue in general quality control and German food regulation

    Directory of Open Access Journals (Sweden)

    Holz Birger

    2008-03-01

    Full Text Available Abstract Background The determination of the osmolality of aqueous samples using a freezing point osmometer is a well-established, routine laboratory method. In addition to their use in clinical and pharmaceutical laboratories, freezing point osmometers are also employed in food testing laboratories. One application is the determination of the osmolality of milk. Although cow's milk is a natural product whose water content is approximately 87%, the osmolality of milk is a significant value when the milk is collected from a larger population of animals. This value is used in milk processing to control the water content, based on the German Food Control Regulations for Milk. Results Measurement of the freezing point and osmolality of milk samples was performed with a Knauer Semi-Micro Freezing Point Osmometer. Osmolality was measured for the untreated milk samples and following their dilution (by volume with 10% and 50% water. The measurements were made after 1, 4 and 7 days to evaluate changes over time. All measurement values for the undiluted milk were spread over a small interval with an average of 271 mOsmol/kg. After mixing the milk samples with 10% water, the average decreased to 242 mOsmol/kg, while mixing with 50% water resulted in an average osmolality of 129 mOsmol/kg. There was no significant change for the osmolality within the 7 days (measurements from days 1, 4 and 7. Conclusion The results observed demonstrate clearly that the additional water content of milk can be determined easily using a freezing point osmometer. Milk samples that contain additional water have a significantly decreased osmolality, corresponding to an increased freezing point. The effect on osmolality of ageing the milk samples could not be determined in this study's time-dependent measurements.

  18. Investigating Freezing Point Depression and Cirrus Cloud Nucleation Mechanisms Using a Differential Scanning Calorimeter

    Science.gov (United States)

    Bodzewski, Kentaro Y.; Caylor, Ryan L.; Comstock, Ashley M.; Hadley, Austin T.; Imholt, Felisha M.; Kirwan, Kory D.; Oyama, Kira S.; Wise, Matthew E.

    2016-01-01

    A differential scanning calorimeter was used to study homogeneous nucleation of ice from micron-sized aqueous ammonium sulfate aerosol particles. It is important to understand the conditions at which these particles nucleate ice because of their connection to cirrus cloud formation. Additionally, the concept of freezing point depression, a topic…

  19. Surface freezing of water

    OpenAIRE

    P?rez-D?az, J. L.; ?lvarez-Valenzuela, M. A.; Rodr?guez-Celis, F.

    2016-01-01

    Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered?exclusively?by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on ...

  20. EPINEPHRINE CONCENTRATION IN WILD BOAR (SUS SCROFA L. SERUM AFTER REPEATED ELISA TESTED FREEZE-THAWING CYCLES

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    Neška Vukšić

    2013-06-01

    Full Text Available Blood samples for determining of epinephrine concentration and biochemical parameters in the blood serum of wild boars were taken from 42 healthy wild boars, both sexes, during the hunting season. All animals in good condition, body weight 20 to 95 kg, were divided into two groups up to 50 kg (group A and up to 95 kg (Group B. Epinephrine concentration was determined by ELISA twice: one week after taking samples and a month after repeated freezing at -80°C. It was higher in relation to the reference value of domestic pigs and human (109.45 pg/ml in A and 119.54 pg/ml in B group. Repeated freezing and re-analysis after a month were resulted in lower concentrations of epinephrine (12% in young and 11.17% in adult animal, but without statistical significance (P>0.05. Biochemical analysis results’ show increased glucose and triglycerides concentrations compared to the reference values, while other indicators were observed within or slightly increased referring to the normal range. The correlation between glucose and epinephrine was not determined.

  1. ADAM-12 stability in first trimester maternal serum.

    Science.gov (United States)

    Cowans, N J; Stamatopoulou, A; Jaakohuhta, S; Spencer, K

    2010-06-01

    Maternal serum A Disintergrin And Metaloprotease-12 (ADAM-12) has been proposed as a marker for prenatal screening of chromosomal abnormalities, pre-eclampsia and other adverse pregnancy outcomes. In this study, we examine the stability of ADAM-12 with time and at different temperatures. Maternal serum and whole blood pools were stored at 30 degrees C, room temperature and refrigerator temperature or subjected to repeated freeze-thaw cycles. ADAM-12 was measured at set time points using an automated DELFIA research assay. Using a 10% change in concentration as a limit of stability, ADAM-12 is stable in serum for less than 15 h at 30 degrees C, less than 20 h at room temperature and for 51 h at refrigerator temperature. ADAM-12 levels are not altered following three - 20 degrees C to room temperature freeze-thaw cycles. The stability of ADAM-12 in whole blood appears similar to that in serum. The findings of this study suggest that ADAM-12 may be unstable under many routine laboratory conditions, and the marker's instability may also be partly responsible for the discrepancies in the literature.

  2. Optimization of protectant, salinity and freezing condition for freeze-drying preservation of Edwardsiella tarda

    Science.gov (United States)

    Yu, Yongxiang; Zhang, Zheng; Wang, Yingeng; Liao, Meijie; Li, Bin; Xue, Liangyi

    2017-10-01

    Novel preservation condition without ultra-low temperature is needed for the study of pathogen in marine fishes. Freeze-drying is such a method usually used for preservation of terrigenous bacteria. However, studies using freeze-drying method to preserving marine microorganisms remain very limited. In this study, we optimized the composition of protectants during the freeze-drying of Edwardsiella tarda, a fish pathogen that causes systemic infection in marine fishes. We found that the optimal composition of protectant mixture contained trehalose (8.0%), skim milk (12.0%), sodium citrate (2.0%), serum (12.0%) and PVP (2.0%). Orthogonal and interaction analyses demonstrated the interaction between serum and skim milk or sodium citrate. The highest survival rate of E. tarda was observed when the concentration of NaCl was 10.0, 30.0 and between 5.0 and 10.0 g L-1 for preparing TSB medium, E. tarda suspension and protectant mixture, respectively. When E. tarda was frozen at -80°C or -40°C for 6 h, its survival rate was higher than that under other tested conditions. Under the optimized conditions, when the protectant mixture was used during freeze-drying process, the survival rate (79.63%-82.30%) of E. tarda was significantly higher than that obtained using single protectant. Scanning electron microscopy (SEM) image indicated that E. tarda was embedded in thick matrix with detectable aggregation. In sum, the protectant mixture may be used as a novel cryoprotective additive for E. tarda.

  3. The freezing and supercooling of garlic (Allium sativum L.)

    Energy Technology Data Exchange (ETDEWEB)

    James, Christian; Seignemartin, Violaine; James, Stephen J. [Food Refrigeration and Process Engineering Research Centre (FRPERC), University of Bristol, Churchill Building, Langford, Bristol BS40 5DU (United Kingdom)

    2009-03-15

    This work shows that peeled garlic cloves demonstrate significant supercooling during freezing under standard conditions and can be stored at temperatures well below their freezing point (-2.7 C) without freezing. The nucleation point or 'metastable limit temperature' (the point at which ice crystal nucleation is initiated) of peeled garlic cloves was found to be between -7.7 and -14.6 C. Peeled garlic cloves were stored under static air conditions at temperatures between -6 and -9 C for up to 69 h without freezing, and unpeeled whole garlic bulbs and cloves were stored for 1 week at -6 C without freezing. (author)

  4. Surface freezing of water.

    Science.gov (United States)

    Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

    2016-01-01

    Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

  5. Freeze-dried plasma at the point of injury: from concept to doctrine.

    Science.gov (United States)

    Glassberg, Elon; Nadler, Roy; Gendler, Sami; Abramovich, Amir; Spinella, Philip C; Gerhardt, Robert T; Holcomb, John B; Kreiss, Yitshak

    2013-12-01

    While early plasma transfusion for the treatment of patients with ongoing major hemorrhage is widely accepted as part of the standard of care in the hospital setting, logistic constraints have limited its use in the out-of-hospital setting. Freeze-dried plasma (FDP), which can be stored at ambient temperatures, enables early treatment in the out-of-hospital setting. Point-of-injury plasma transfusion entails several significant advantages over currently used resuscitation fluids, including the avoidance of dilutional coagulopathy, by minimizing the need for crystalloid infusion, beneficial effects on endothelial function, physiological pH level, and better maintenance of intravascular volume compared with crystalloid-based solutions. The Israel Defense Forces Medical Corps policy is that plasma is the resuscitation fluid of choice for selected, severely wounded patients and has thus included FDP as part of its armamentarium for use at the point of injury by advanced life savers, across the entire military. We describe the clinical rationale behind the use of FDP at the point-of-injury, the drafting of the administration protocol now being used by Israel Defense Forces advanced life support providers, the process of procurement and distribution, and preliminary data describing the first casualties treated with FDP at the point of injury. It is our hope that others will be able to learn from our experience, thus improving trauma casualty care around the world.

  6. Non-Toxic, Low-Freezing, Drop-In Replacement Heat Transfer Fluids

    Science.gov (United States)

    Cutbirth, J. Michael

    2012-01-01

    A non-toxic, non-flammable, low-freezing heat transfer fluid is being developed for drop-in replacement within current and future heat transfer loops currently using water or alcohol-based coolants. Numerous water-soluble compounds were down-selected and screened for toxicological, physical, chemical, compatibility, thermodynamic, and heat transfer properties. Two fluids were developed, one with a freezing point near 0 C, and one with a suppressed freezing point. Both fluids contain an additive package to improve material compatibility and microbial resistance. The optimized sub-zero solution had a freezing point of 30 C, and a freezing volume expansion of 10-percent of water. The toxicity of the solutions was experimentally determined as LD(50) greater than 5g/kg. The solutions were found to produce minimal corrosion with materials identified by NASA as potentially existing in secondary cooling loops. Thermal/hydrodynamic performance exceeded that of glycol-based fluids with comparable freezing points for temperatures Tf greater than 20 C. The additive package was demonstrated as a buffering agent to compensate for CO2 absorption, and to prevent microbial growth. The optimized solutions were determined to have physically/chemically stable shelf lives for freeze/thaw cycles and longterm test loop tests.

  7. Optimization of thermophysical properties of Pacific white shrimp (Litopenaeus vannamei) previously treated with freezing-point regulators using response surface methodology.

    Science.gov (United States)

    Wang, Liang; Liu, Zunying; Zhao, Yuanhui; Dong, Shiyuan; Zeng, Mingyong; Yang, Huicheng

    2015-08-01

    Three freezing-point regulators (glycine, sodium chloride and D-sorbitol) were employed to optimize thermophysical properties of Pacific white shrimp (Litopenaeus vannamei) using response surface methodology (RSM). The independent variables were glycine content (0.250-1.250 %), sodium chloride content (0.500-2.500 %) and D-sorbitol content (0.125-0.625 %) and analysis of variance showed that the effects of glycine, sodium chloride and D-sorbitol on the thermophysical properties were statistically significant (P thermophysical properties were T i , - 5.086 °C; W u , 17.222 %; C app , 41.038 J/g °C and H, 155.942 J/g, respectively. Briefly, the application of freezing-point regulators depressed T i and obtained the optimum W u , C app and H, which would be obviously beneficial for the exploitation of various thermal processing and food storage.

  8. Momentum anisotropy at freeze out

    International Nuclear Information System (INIS)

    Feld, S.; Borghini, N.; Lang, C.

    2017-01-01

    The transition from a hydrodynamical modeling to a particle-based approach is a crucial element of the description of high-energy heavy-ion collisions. Assuming this “freeze out” happens instantaneously at each point of the expanding medium, we show that the local phase-space distribution of the emitted particles is asymmetric in momentum space. This suggests the use of anisotropic hydrodynamics for the last stages of the fluid evolution. We discuss how observables depend on the amount of momentum-space anisotropy at freeze out and how smaller or larger anisotropies allow for different values of the freeze-out temperature. (paper)

  9. SLAPex Freeze/Thaw 2015: The First Dedicated Soil Freeze/Thaw Airborne Campaign

    Science.gov (United States)

    Kim, Edward; Wu, Albert; DeMarco, Eugenia; Powers, Jarrett; Berg, Aaron; Rowlandson, Tracy; Freeman, Jacqueline; Gottfried, Kurt; Toose, Peter; Roy, Alexandre; hide

    2016-01-01

    Soil freezing and thawing is an important process in the terrestrial water, energy, and carbon cycles, marking the change between two very different hydraulic, thermal, and biological regimes. NASA's Soil Moisture Active/Passive (SMAP) mission includes a binary freeze/thaw data product. While there have been ground-based remote sensing field measurements observing soil freeze/thaw at the point scale, and airborne campaigns that observed some frozen soil areas (e.g., BOREAS), the recently-completed SLAPex Freeze/Thaw (F/T) campaign is the first airborne campaign dedicated solely to observing frozen/thawed soil with both passive and active microwave sensors and dedicated ground truth, in order to enable detailed process-level exploration of the remote sensing signatures and in situ soil conditions. SLAPex F/T utilized the Scanning L-band Active/Passive (SLAP) instrument, an airborne simulator of SMAP developed at NASA's Goddard Space Flight Center, and was conducted near Winnipeg, Manitoba, Canada, in October/November, 2015. Future soil moisture missions are also expected to include soil freeze/thaw products, and the loss of the radar on SMAP means that airborne radar-radiometer observations like those that SLAP provides are unique assets for freeze/thaw algorithm development. This paper will present an overview of SLAPex F/T, including descriptions of the site, airborne and ground-based remote sensing, ground truth, as well as preliminary results.

  10. Direct comparative analysis of conventional and directional freezing for the cryopreservation of whole ovaries

    NARCIS (Netherlands)

    Maffei, S.; Hanenberg, M.; Pennarossa, G.; Roberto V. Silva, J.; Tiziana, A.; Brevini, L.; Pharm, D.; Arav, A.; Gandolfi, F.

    2013-01-01

    INTERVENTION(S): Eighty-one ovaries were randomly assigned to fresh control, conventional freezing (CF), and directional freezing (DF) group. Ovaries of CF and DF groups were perfused via the ovarian artery with Leibovitz L-15 medium, 10% fetal bovine serum, and 1.5 M dimethyl sulfoxide for 5

  11. Effects of freezing conditions on quality changes in blueberries.

    Science.gov (United States)

    Cao, Xuehui; Zhang, Fangfang; Zhao, Dongyu; Zhu, Danshi; Li, Jianrong

    2018-03-12

    Freezing preservation is one of the most effective methods used to maintain the flavour and nutritional value of fruit. This research studied the effects of different freezing conditions, -20 °C, -40 °C, -80 °C, and immersion in liquid nitrogen, on quality changes of freeze-thawed blueberries. The water distribution estimates of blueberries were measured based on low-field nuclear magnetic resonance (LF-NMR) analysis. The pectin content, drip loss, and fruit texture were also detected to evaluate quality changes in samples. The freezing curves of blueberry showed super-cooling points at -20 °C and - 40 °C, whereas super-cooling points were not observed at -80 °C or in liquid nitrogen. After freeze-thaw treatment, the relaxation time of the cell wall water (T 21 ), cytoplasm water and extracellular space (T 22 ), and vacuole water (T 23 ) were significantly shortened compared to fresh samples, which suggested a lower liquidity. Although the freezing speed for samples immersed in liquid nitrogen was faster than other treatments, samples treated at -80 °C showed better quality regarding vacuole water holding, drip loss, and original pectin content retention. This study contributed to understanding how freezing temperature affects the qualities of blueberries. The super-fast freezing rate might injure fruit, and an appropriate freezing rate could better preserve blueberries. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

  12. Freezing of Lennard-Jones-type fluids

    International Nuclear Information System (INIS)

    Khrapak, Sergey A.; Chaudhuri, Manis; Morfill, Gregor E.

    2011-01-01

    We put forward an approximate method to locate the fluid-solid (freezing) phase transition in systems of classical particles interacting via a wide range of Lennard-Jones-type potentials. This method is based on the constancy of the properly normalized second derivative of the interaction potential (freezing indicator) along the freezing curve. As demonstrated recently it yields remarkably good agreement with previous numerical simulation studies of the conventional 12-6 Lennard-Jones (LJ) fluid [S.A.Khrapak, M.Chaudhuri, G.E.Morfill, Phys. Rev. B 134, 052101 (2010)]. In this paper, we test this approach using a wide range of the LJ-type potentials, including LJ n-6 and exp-6 models, and find that it remains sufficiently accurate and reliable in reproducing the corresponding freezing curves, down to the triple-point temperatures. One of the possible application of the method--estimation of the freezing conditions in complex (dusty) plasmas with ''tunable'' interactions--is briefly discussed.

  13. Realization of Copper Melting Point for Thermocouple Calibrations

    Directory of Open Access Journals (Sweden)

    Y. A. ABDELAZIZ

    2011-08-01

    Full Text Available Although the temperature stability and uncertainty of the freezing plateau is better than that of the melting plateau in most of the thermometry fixed points, but realization of melting plateaus are easier than that of freezing plateaus for metal fixed points. It will be convenient if the melting points can be used instead of the freezing points in calibration of standard noble metal thermocouples because of easier realization and longer plateau duration of melting plateaus. In this work a comparison between the melting and freezing points of copper (Cu was carried out using standard noble metal thermocouples. Platinum - platinum 10 % rhodium (type S, platinum – 30 % rhodium / platinum 6 % rhodium (type B and platinum - palladium (Pt/Pd thermocouples are used in this study. Uncertainty budget analysis of the melting points and freezing points is presented. The experimental results show that it is possible to replace the freezing point with the melting point of copper cell in the calibration of standard noble metal thermocouples in secondary-level laboratories if the optimal methods of realization of melting points are used.

  14. Aqueous Solubility of Piperazine and 2-Amino-2-methyl-1-propanol plus Their Mixtures Using an Improved Freezing-Point Depression Method

    DEFF Research Database (Denmark)

    Fosbøl, Philip Loldrup; Neerup, Randi; Waseem Arshad, Muhammad

    2011-01-01

    In this work the solid–liquid equilibrium (SLE) and freezing-point depression (FPD) in the electrolytic binary aqueous systems piperazine (PZ, CAS No. 110-85-0) and aqueous 2-amino-2-methyl-1-propanol (AMP, CAS No. 124-68-5) were measured. The FPD and solubility were also determined in the ternary...

  15. Generalized correlation of latent heats of vaporization of coal liquid model compounds between their freezing points and critical points

    Energy Technology Data Exchange (ETDEWEB)

    Sivaraman, A.; Kobuyashi, R.; Mayee, J.W.

    1984-02-01

    Based on Pitzer's three-parameter corresponding states principle, the authors have developed a correlation of the latent heat of vaporization of aromatic coal liquid model compounds for a temperature range from the freezing point to the critical point. An expansion of the form L = L/sub 0/ + ..omega..L /sub 1/ is used for the dimensionless latent heat of vaporization. This model utilizes a nonanalytic functional form based on results derived from renormalization group theory of fluids in the vicinity of the critical point. A simple expression for the latent heat of vaporization L = D/sub 1/epsilon /SUP 0.3333/ + D/sub 2/epsilon /SUP 0.8333/ + D/sub 4/epsilon /SUP 1.2083/ + E/sub 1/epsilon + E/sub 2/epsilon/sup 2/ + E/sub 3/epsilon/sup 3/ is cast in a corresponding states principle correlation for coal liquid compounds. Benzene, the basic constituent of the functional groups of the multi-ring coal liquid compounds, is used as the reference compound in the present correlation. This model works very well at both low and high reduced temperatures approaching the critical point (0.02 < epsilon = (T /SUB c/ - T)/(T /SUB c/- 0.69)). About 16 compounds, including single, two, and three-ring compounds, have been tested and the percent root-mean-square deviations in latent heat of vaporization reported and estimated through the model are 0.42 to 5.27%. Tables of the coefficients of L/sub 0/ and L/sub 1/ are presented. The contributing terms of the latent heat of vaporization function are also presented in a table for small increments of epsilon.

  16. Stability of BDNF in Human Samples Stored Up to 6 Months and Correlations of Serum and EDTA-Plasma Concentrations.

    Science.gov (United States)

    Polyakova, Maryna; Schlögl, Haiko; Sacher, Julia; Schmidt-Kassow, Maren; Kaiser, Jochen; Stumvoll, Michael; Kratzsch, Jürgen; Schroeter, Matthias L

    2017-06-03

    Brain-derived neurotrophic factor (BDNF), an important neural growth factor, has gained growing interest in neuroscience, but many influencing physiological and analytical aspects still remain unclear. In this study we assessed the impact of storage time at room temperature, repeated freeze/thaw cycles, and storage at -80 °C up to 6 months on serum and ethylenediaminetetraacetic acid (EDTA)-plasma BDNF. Furthermore, we assessed correlations of serum and plasma BDNF concentrations in two independent sets of samples. Coefficients of variations (CVs) for serum BDNF concentrations were significantly lower than CVs of plasma concentrations ( n = 245, p = 0.006). Mean serum and plasma concentrations at all analyzed time points remained within the acceptable change limit of the inter-assay precision as declared by the manufacturer. Serum and plasma BDNF concentrations correlated positively in both sets of samples and at all analyzed time points of the stability assessment ( r = 0.455 to r s = 0.596; p plasma up to 6 months. Due to a higher reliability, we suggest favoring serum over EDTA-plasma for future experiments assessing peripheral BDNF concentrations.

  17. Transition from natural-convection-controlled freezing to conduction-controlled freezing

    International Nuclear Information System (INIS)

    Sparrow, E.M.; Ramsey, J.W.; Harris, J.S.

    1981-01-01

    Experiments were performed to study the transition between freezing controlled by natural convection in the liquid adjacent to a freezing interface and freezing controlled by heat conduction in the solidified material. The freezing took place on a cooled vertical tube immersed in an initially superheated liquid contained in an adiabatic-walled vessel. At early and intermediate times, temperature differences throughout the liquid induce a vigorous natural convection motion which retards freezing, but the temperature differences diminish with time and natural convection ebbs. At large times, the freezing rate is fully controlled by heat conduction in the solidified material. The frozen specimens for short and intermediate freezing times are smooth-surfaced and tapered, while those for large times are straight-sided and have surfaces that are overlaid with a thicket of large discrete crystals. These characteristics correspond respectively to those of natural-convection- controlled freezing and conduction-controlled freezing. At early times, the measured mass of the frozen material is identical to that for natural-convection-controlled freezing and conduction-controlled freezing. At early times, the measured mass of the frozen material is identical to that for natural-convection-controlled freezing. At later times, the frozen mass tends to approach that for conduction-controlled freezing, but a residual deficit remains

  18. Effects of lactation number, milk yield and milk composition on freezing point of milk of Polish Holstein-Friesian cows

    OpenAIRE

    Agnieszka Otwinowska-Mindur; Ewa PTAK

    2018-01-01

    The objective of the study was to assess the influence of lactation number, daily milk yield, somatic cell count and milk composition on the freezing point of milk of Polish Holstein-Friesian cows. The data comprised 3,067,343 test day milk samples collected in 2014 from 865,198 first seven lactations of 714,018 Polish Holstein-Friesian cows, made available by the Polish Federation of Cattle Breeders and Dairy Farmers. The cows calved in 20,043 herds in 2013 and 2014. Four lactation classes w...

  19. Charge-charge liquid structure factor and the freezing of alkali halides

    International Nuclear Information System (INIS)

    March, N.H.; Tosi, M.P.

    1980-10-01

    The peak height of the charge-charge liquid structure factor Ssub(QQ) in molten alkali halides is proposed as a criterion for freezing. Available data on molten alkali chlorides, when extrapolated to the freezing point suggests Ssub(QQ)sup(max) approximately 5. (author)

  20. Cold Heat Storage Characteristics of O/W-type Latent Heat Emulsion Including Continuum Phase of Water Treated with a Freezing Point Depression

    Science.gov (United States)

    Inaba, Hideo; Morita, Shin-Ichi

    This paper deals with flow and cold heat storage characteristics of the oil (tetradecane, C14H30, freezing point 278.9 K, Latent heat 229 kJ/kg)/water emulsion as a latent heat storage material having a low melting point. The test emulsion includes a water-urea solution as a continuum phase. The freezing point depression of the continuum phase permits enhancement of the heat transfer rate of the emulison, due to the large temperature difference between the latent heat storage material and water-urea solution. The velocity of emulsion flow and the inlet temperature of coolant in a coiled double tube heat exchanger are chosen as the experimental parameters. The pressure drop, the heat transfer coefficient of the emulsion in the coiled tube are measured in the temperture region over solid and liquid phase of the latent heat storage material. The finishing time of the cold heat storage is defined experimentally in the range of sensible and latent heat storage. It is clarified that the flow behavior of the emulsion as a non-Newtonian fluid has an important role in cold heat storage. The useful nondimentional correlation equations for the additional pressure loss coefficient, the heat transfer coefficient and the finishing time of the cold heat storage are derived in terms of Dean number and heat capacity ratio.

  1. Phase equilibrium condition measurements in nitrogen and air clathrate hydrate forming systems at temperatures below freezing point of water

    International Nuclear Information System (INIS)

    Yasuda, Keita; Oto, Yuya; Shen, Renkai; Uchida, Tsutomu; Ohmura, Ryo

    2013-01-01

    Highlights: • Phase equilibrium conditions in the nitrogen and modelled air hydrate forming systems are measured. • Measurements are conducted at temperatures below the freezing point of water. • Results have relevance to the air hydrate formation in the ice sheets. • Measured data are quantitatively compared with the previously reported values. • Range of the equilibrium measurements was from (242 to 268) K. -- Abstract: Contained in this paper are the three phase equilibrium conditions of the (ice + clathrate hydrate + guest-rich) vapour in the (nitrogen + water) and the modelled (air + water) systems at temperatures below the freezing point of water. The precise determination of the equilibrium conditions in those systems are of importance for the analysis of the past climate change using the cored samples from the ice sheets at Antarctica and Greenland because the air hydrates keep the ancient climate signals. The mole ratio of the modelled air composed of nitrogen and oxygen is 0.790:0.210. The equilibrium conditions were measured by the batch, isochoric procedure. The temperature range of the measurements in the nitrogen hydrate forming system is (244.05 < T < 266.55) K and the corresponding equilibrium pressure range is (7.151 < p < 12.613) MPa. The temperature range of the measurements in the modelled air hydrate forming system is (242.55 < T < 267.85) K, and the corresponding equilibrium pressure range is (6.294 < p < 12.144) MPa. The data obtained quantitatively compared with the previously reported data

  2. Key composition optimization of meat processed protein source by vacuum freeze-drying technology

    Directory of Open Access Journals (Sweden)

    Yan Ma

    2018-05-01

    Full Text Available Vacuum freeze-drying technology is a high technology content, a wide range of knowledge of technology in the field of drying technology is involved, it is also a method of the most complex drying equipment, the largest energy consumption, the highest cost of drying method, but due to the particularity of its dry goods: the freeze-drying food has the advantages of complex water performance is good, cooler and luster of freezing and drying food to maintain good products, less nutrient loss, light weight, easy to carry transportation, easy to long-term preservation, and on the quality is far superior to the obvious advantages of other dried food, making it become the forefront of drying technology research and development. The freeze-drying process of Chinese style ham and western Germany fruit tree tenderloin is studied in this paper, their eutectic point, melting point and collapse temperature, freeze-drying curve and its heat and mass transfer characteristics are got, then the precool temperature and the highest limiting temperature of sublimation interface are determined. The effect of system pressure on freeze-dried rate in freeze-drying process is discussed, and the method of regulating pressure circularly is determined. Keywords: Ham, Tenderloin, Vacuum freeze-dry, Processing, Optimization

  3. Key composition optimization of meat processed protein source by vacuum freeze-drying technology.

    Science.gov (United States)

    Ma, Yan; Wu, Xingzhuang; Zhang, Qi; Giovanni, Vigna; Meng, Xianjun

    2018-05-01

    Vacuum freeze-drying technology is a high technology content, a wide range of knowledge of technology in the field of drying technology is involved, it is also a method of the most complex drying equipment, the largest energy consumption, the highest cost of drying method, but due to the particularity of its dry goods: the freeze-drying food has the advantages of complex water performance is good, cooler and luster of freezing and drying food to maintain good products, less nutrient loss, light weight, easy to carry transportation, easy to long-term preservation, and on the quality is far superior to the obvious advantages of other dried food, making it become the forefront of drying technology research and development. The freeze-drying process of Chinese style ham and western Germany fruit tree tenderloin is studied in this paper, their eutectic point, melting point and collapse temperature, freeze-drying curve and its heat and mass transfer characteristics are got, then the precool temperature and the highest limiting temperature of sublimation interface are determined. The effect of system pressure on freeze-dried rate in freeze-drying process is discussed, and the method of regulating pressure circularly is determined.

  4. Cryopreservation of boar semen. II: Effect of cooling rate and duration of freezing point plateau on boar semen frozen in mini- and maxi-straws and plastic bags.

    Science.gov (United States)

    Bwanga, C O; Einarsson, S; Rodriguez-Martinez, H

    1991-01-01

    The post-thaw motility and the acrosome integrity of semen from 4 boars frozen with a programmable freezing machine, in mini (0.25 ml) and maxi (5 ml) plastic straws and in 10 x 5 cm Teflon FEP-plastic bags (0.12 mm thick, 5 ml), were compared. The freezing of the semen was monitored by way of thermo-couples placed in the straws and the bags. Three freezing programmes were used, namely A: from +5 degrees C, at a rate of 3 degrees C/min, to -6 degrees C, held for 1 min at -6 degrees C, and followed by a cooling rate of 20 degrees C/min to -100 degrees C; B: a similar curve except that there was no holding time at -6 degrees C and that the cooling rate was 30 degrees C/min, and C: from +5 degrees C to -100 degrees C, with a cooling rate of 35 degrees C/min, followed by storage in liquid N2. Despite the freezing curve assayed, both the mini-straws and the bags depicted much shorter freezing point plateaus as compared to the maxi-straws. Post-thaw sperm motility as well as the amount of normal apical ridges were equally significantly higher when semen was frozen in mini-straws or in bags than in maxi-straws. Significant differences in these post-thawing parameters were obtained between the freezing curves used. The stepwise freezing procedure A appeared as the best alternative for boar semen, considering this in vitro evaluation.

  5. Temperatura letal de diferentes plantas frutíferas tropicais Freezing points of various tropical fruits

    Directory of Open Access Journals (Sweden)

    Paulo Cesar Sentelhas

    1996-01-01

    Full Text Available Com o objetivo de conhecer melhor o efeito das baixas temperaturas sobre as frutíferas de clima tropical e possibilitar o desenvolvimento de novas variedades, mais tolerantes, simularam-se geadas em câmaras frigoríficas para a determinação da temperatura letal de diferentes plantas frutíferas tropicais. Os resultados permitiram classificar as espécies em três grupos: Grupo I - moderada tolerância (-4°C: condessa (Annona reticulata; goiaba (Psidium guajava; acerola (Malpighia glabra e abacate (Persea americana var. Geada; Grupo II - média tolerância (-5°C: conde (A. squamosa; araticum-mirim (Rollinea spp.; anona-do-brejo (A. glabra; falsa-gravioleira (A. montana; araticum-de-folha-miúda (R. ermaginata e maracujá-amarelo (Passiflora edulis f. flavicarpa; Grupo III - acentuada tolerância (-6°C: cherimóia (A. cherimola.The effect of low temperature on tropical fruits was studied in order to guide future developments of frost resistant varieties. Simulations of frost were done in a freezing chamber to determine the freezing points of various fruit plants. On the basis of the results the studied species can be classified into three groups according to their tolerance to low temperatures: Group I - little tolerance (-4°C: Annona reticulata; Psidium guajava; Malpighia glabra and Persea americana (var. Geada; Group II - medium tolerance (-5°C: A. squamosa; Rollinea spp.; A. glabra; A. montana; R. ermaginata and Passiflora edulis f. flavicarpa; Group III - high tolerance (-6°C: A. cherimola.

  6. Chosen biotic factors influencing raw cow milk freezing point

    Directory of Open Access Journals (Sweden)

    Oto Hanuš

    2011-01-01

    Full Text Available The milk freezing point depression (FPD is important physical property. FPD is influenced by milk composition especially by components with osmotic pressure activity and by other physiological factors. There is possible to indicate a foreign (extraneous water addition into milk by FPD. This is necessary to have a good estimated legislative FPD discrimination limit (FPD–L for purpose of milk quality control. This paper was aimed at obtaining information to improve such estimation. Impacts factors as season variations, estimated state of dairy cow nutrition and some milk components and properties on milk FPD and their relations to FPD were quantified (n 11 540 – 72 607 bulk raw cow milk samples. The highest FPD was in Spring (−0.52097 ± 0.004877 °C, the lowest in Autumn (−0.52516 ± 0.005725 °C; P < 0.001. Correlation between FPD and lactose was 0.35 (P < 0.001. 12% and 5.4% of FPD variability is explainable by lactose and casein variability. Relationship between FPD and urea (U was 0.26 (P < 0.001 in March. The worst FPD was in group with presupposed (according to milk urea and protein combination nitrogen matter (NM and energy (E insufficiency (−0.51855 ± 0.007288 °C. The best FPD was in group with presupposed NM and E surplus in feeding ration (−0.52536 ± 0.004785 °C; P < 0.001. The FPD was worse in suspicion on E deficiency (on the basis of fat/crude protein ratio as compared to presumption for balanced E nourishment of dairy herds (−0.52105 ± 0.006436 °C > −0.52244 ± 0.005367 °C; P < 0.001. Results can improve the estimation of objective FPD–L.

  7. Effects of Pressure-shift Freezing on the Structural and Physical Properties of Gelatin Hydrogel Matrices

    Science.gov (United States)

    Kim, Byeongsoo; Gil, Hyung Bae; Min, Sang-Gi; Lee, Si-Kyung; Choi, Mi-Jung

    2014-01-01

    This study investigates the effects of the gelatin concentration (10-40%, w/v), freezing temperatures (from -20℃ to -50℃) and freezing methods on the structural and physical properties of gelatin matrices. To freeze gelatin, the pressure-shift freezing (PSF) is being applied at 0.1 (under atmospheric control), 50 and 100 MPa, respectively. The freezing point of gelatin solutions decrease with increasing gelatin concentrations, from -0.2℃ (10% gelatin) to -6.7℃ (40% gelatin), while the extent of supercooling did not show any specific trends. The rheological properties of the gelatin indicate that both the storage (G') and loss (G") moduli were steady in the strain amplitude range of 0.1-10%. To characterize gelatin matrices formed by the various freezing methods, the ice crystal sizes which were being determined by the scanning electron microscopy (SEM) are affected by the gelatin concentrations. The ice crystal sizes are affected by gelatin concentrations and freezing temperature, while the size distributions of ice crystals depend on the freezing methods. Smaller ice crystals are being formed with PSF rather than under the atmospheric control where the freezing temperature is above -40℃. Thus, the results of this study indicate that the PSF processing at a very low freezing temperature (-50℃) offers a potential advantage over commercial atmospheric freezing points for the formation of small ice crystals. PMID:26760743

  8. Microbial analysis and survey test of gamma-irradiated freeze-dried fruits for patient's food

    Science.gov (United States)

    Park, Jae-Nam; Sung, Nak-Yun; Byun, Eui-Hong; Byun, Eui-Baek; Song, Beom-Seok; Kim, Jae-Hun; Lee, Kyung-A.; Son, Eun-Joo; Lyu, Eun-Soon

    2015-06-01

    This study examined the microbiological and organoleptic qualities of gamma-irradiated freeze-dried apples, pears, strawberries, pineapples, and grapes, and evaluated the organoleptic acceptability of the sterilized freeze-dried fruits for hospitalized patients. The freeze-dried fruits were gamma-irradiated at 0, 1, 2, 3, 4, 5, 10, 12, and 15 kGy, and their quality was evaluated. Microorganisms were not detected in apples after 1 kGy, in strawberries and pears after 4 kGy, in pineapples after 5 kGy, and in grapes after 12 kGy of gamma irradiation. The overall acceptance score, of the irradiated freeze-dried fruits on a 7-point scale at the sterilization doses was 5.5, 4.2, 4.0, 4.1, and 5.1 points for apples, strawberries, pears, pineapples, and grapes, respectively. The sensory survey of the hospitalized cancer patients (N=102) resulted in scores of 3.8, 3.7, 3.9, 3.9, and 3.7 on a 5-point scale for the gamma-irradiated freeze-dried apples, strawberries, pears, pineapples, and grapes, respectively. The results suggest that freeze-dried fruits can be sterilized with a dose of 5 kGy, except for grapes, which require a dose of 12 kGy, and that the organoleptic quality of the fruits is acceptable to immuno-compromised patients. However, to clarify the microbiological quality and safety of freeze-dried fruits should be verified by plating for both aerobic and anaerobic microorganisms.

  9. Freezing for Love

    DEFF Research Database (Denmark)

    Carroll, Katherine; Kroløkke, Charlotte

    2018-01-01

    The promise of egg freezing for women’s fertility preservation entered feminist debate in connection with medical and commercial control over, and emancipation from, biological reproduction restrictions. In this paper we explore how women negotiate and make sense of the decision to freeze...... their eggs. Our analysis draws on semi-structured interviews with 16 women from the Midwest and East Coast regions of the USA who froze their eggs. Rather than freezing to balance career choices and ‘have it all’, the women in this cohort were largely ‘freezing for love’ and in the hope of having their ‘own...... healthy baby’. This finding extends existing feminist scholarship and challenges bioethical concerns about egg freezing by drawing on the voices of women who freeze their eggs. By viewing egg freezing as neither exclusively liberation nor oppression or financial exploitation, this study casts egg freezing...

  10. Analytical validation and reference intervals for freezing point depression osmometer measurements of urine osmolality in dogs.

    Science.gov (United States)

    Guerrero, Samantha; Pastor, Josep; Tvarijonaviciute, Asta; Cerón, José Joaquín; Balestra, Graziano; Caldin, Marco

    2017-11-01

    Urine osmolality (UOsm) is considered the most accurate measure of urine concentration and is used to assess body fluid homeostasis and renal function. We performed analytical validation of freezing point depression measurement of canine UOsm, to establish reference intervals (RIs) and to determine the effect of age, sex, and reproductive status on UOsm in dogs. Clinically healthy dogs ( n = 1,991) were retrospectively selected and stratified in groups by age (young [0-12 mo], adults [13-84 mo], and seniors [>84 mo]), sex (females and males), and reproductive status (intact and neutered). RIs were calculated for each age group. Intra- and inter-assay coefficients of variation were dogs, and 366-2,178 mOsm/kg in seniors. Senior dogs had a significantly lower UOsm than young and adult dogs ( p dogs ( p dogs.

  11. Influence of freezing down to 77.15 K on structure and antioxidant power of some proteins

    Science.gov (United States)

    Rozanova, S. L.; Narozhnyi, S. V.; Nardid, O. A.

    2017-06-01

    The purpose of the present work was to investigate influence of different freeze-thawing protocols on structure and antioxidant properties of isolated proteins. In our experiments we have studied human serum albumin, human hemoglobin and cytochrome C derived from equine heart frozen down to 77.15 K with 1-2 deg/min and 300 deg/min rate with following thawing on a water bath at 293.15 K. Native proteins were assumed as a control. Influence of freeze-thawing protocols on protein structure was investigated using spectrophotometric and fluorescent assays. Antioxidant activities of isolated proteins were estimated by their ability to reduce ABTS+ radical. It has been established that unfolding derived from freeze-thawing exposure leads to protein antioxidant activity increasing while decreasing of such an activity may be connected with macromolecule aggregation. Character of freeze-thawing influence on antioxidant activity of proteins depends on molecule structure peculiarities and freezing protocols.

  12. Freezing Bubbles

    Science.gov (United States)

    Kingett, Christian; Ahmadi, Farzad; Nath, Saurabh; Boreyko, Jonathan

    2017-11-01

    The two-stage freezing process of a liquid droplet on a substrate is well known; however, how bubbles freeze has not yet been studied. We first deposited bubbles on a silicon substrate that was chilled at temperatures ranging from -10 °C to -40 °C, while the air was at room temperature. We observed that the freeze front moved very slowly up the bubble, and in some cases, even came to a complete halt at a critical height. This slow freezing front propagation can be explained by the low thermal conductivity of the thin soap film, and can be observed more clearly when the bubble size or the surface temperature is increased. This delayed freezing allows the frozen portion of the bubble to cool the air within the bubble while the top part is still liquid, which induces a vapor pressure mismatch that either collapses the top or causes the top to pop. In cases where the freeze front reaches the top of the bubble, a portion of the top may melt and slowly refreeze; this can happen more than just once for a single bubble. We also investigated freezing bubbles inside of a freezer where the air was held at -20 °C. In this case, the bubbles freeze quickly and the ice grows radially from nucleation sites instead of perpendicular to the surface, which provides a clear contrast with the conduction limited room temperature bubbles.

  13. Selected abiotic factors that influence raw cow milk freezing point depression

    Directory of Open Access Journals (Sweden)

    Oto Hanuš

    2012-01-01

    Full Text Available Freezing point depression (FPD is an important property of milk that is influenced primarily by milk components connected to osmotic pressure. Under certain conditions it is possible to detect the addition of water to milk. It is necessary to have the right FPD limit in legislation for milk quality control. The aim of this study was to improve the estimation procedure of this limit. Apart from factors related to dairy cow nutrition, cattle breed and milk yield, it is important to take into account CO2 (6%, water steam evaporation and pasteurization under technological conditions. Bulk milk samples (1, 30, 6, 6, 10, 1 according to experiment from Holstein and Czech Fleckvieh breed (1:1 were used in the experiments and technologically treated. The effects of water addition (water saturated and unsaturated by CO2, carbon dioxide evaporation and pasteurization (80 °C for 22 min were quantified. Pasteurization aggravation of FPD was -0.00394 ± 0.00171 ºC (P P < 0.001 depending on practice. Increase in FPD is recorded after milking during technological procedures of milk storage, mixing, pumping, transport shaking and warming. During FPD shift, the acuteness of FPD data sets increases. This fact should be considered in the process of deriving standard raw cow milk FPD limits. Similar experimental analysis of milk FPD technological shifts has not been performed in this way until now.

  14. Quality changes and freezing time prediction during freezing and thawing of ginger

    OpenAIRE

    Singha, Poonam; Muthukumarappan, Kasiviswanathan

    2015-01-01

    Abstract Effects of different freezing rates and four different thawing methods on chemical composition, microstructure, and color of ginger were investigated. Computer simulation for predicting the freezing time of cylindrical ginger for two different freezing methods (slow and fast) was done using ANSYS ? Multiphysics. Different freezing rates (slow and fast) and thawing methods significantly (P?

  15. DNA comet assay to identify different freezing temperatures of irradiated liver chicken

    International Nuclear Information System (INIS)

    Duarte, Renato C.; Mozeika, Michel A.; Fanaro, Gustavo B.; Villavicencio, Anna L.C.H.; Marchioni, Eric

    2009-01-01

    The cold chain is a succession of steps which maintain the food at low temperature. The thawed food never be frozen again and the best solution being to consume it quickly to avoid the microorganism growth which causes decay and nutrients damage. One of most important point is that freezing process, unlike irradiation, do not destroy microorganisms, only inactive them as long as they remain in a frozen state. The Comet Assay is an original test used to detect irradiated foods that's recognize the DNA damage and can then be used to control the overall degradation of the food and in a certain extend to evaluate the damage caused by irradiation, different forms of freeze and storage time on liver chicken cells. Different freezing temperatures were used, deep freeze -196 deg C and slow freeze -10 deg C. Samples were irradiated in a 60 Co irradiator with 1.5, 3.0 and 4.5 kGy radiation doses. Fast freezing technique induces a low percent of DNA degradation comparing to slow freezing technique. This procedure could be a good choose to chicken freezing processing. (author)

  16. DNA comet assay to identify different freezing temperatures of irradiated liver chicken

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, Renato C.; Mozeika, Michel A.; Fanaro, Gustavo B.; Villavicencio, Anna L.C.H. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: renatocduarte@yahoo.com.br; Marchioni, Eric [Universite de Strasbourg, Illkirch (France). Faculte de Pharmacie. Lab. de Chimie Analytique et Sciences de l' Aliment

    2009-07-01

    The cold chain is a succession of steps which maintain the food at low temperature. The thawed food never be frozen again and the best solution being to consume it quickly to avoid the microorganism growth which causes decay and nutrients damage. One of most important point is that freezing process, unlike irradiation, do not destroy microorganisms, only inactive them as long as they remain in a frozen state. The Comet Assay is an original test used to detect irradiated foods that's recognize the DNA damage and can then be used to control the overall degradation of the food and in a certain extend to evaluate the damage caused by irradiation, different forms of freeze and storage time on liver chicken cells. Different freezing temperatures were used, deep freeze -196 deg C and slow freeze -10 deg C. Samples were irradiated in a {sup 60}Co irradiator with 1.5, 3.0 and 4.5 kGy radiation doses. Fast freezing technique induces a low percent of DNA degradation comparing to slow freezing technique. This procedure could be a good choose to chicken freezing processing. (author)

  17. Freeze drying method

    International Nuclear Information System (INIS)

    Coppa, N.V.; Stewart, P.; Renzi, E.

    1999-01-01

    The present invention provides methods and apparatus for freeze drying in which a solution, which can be a radioactive salt dissolved within an acid, is frozen into a solid on vertical plates provided within a freeze drying chamber. The solid is sublimated into vapor and condensed in a cold condenser positioned above the freeze drying chamber and connected thereto by a conduit. The vertical positioning of the cold condenser relative to the freeze dryer helps to help prevent substances such as radioactive materials separated from the solution from contaminating the cold condenser. Additionally, the system can be charged with an inert gas to produce a down rush of gas into the freeze drying chamber to also help prevent such substances from contaminating the cold condenser

  18. To freeze or not to freeze embryos: clarity, confusion and conflict.

    Science.gov (United States)

    Goswami, Mohar; Murdoch, Alison P; Haimes, Erica

    2015-06-01

    Although embryo freezing is a routine clinical practice, there is little contemporary evidence on how couples make the decision to freeze their surplus embryos, or of their perceptions during that time. This article describes a qualitative study of 16 couples who have had in vitro fertilisation (IVF) treatment. The study question was 'What are the personal and social factors that patients consider when deciding whether to freeze embryos?' We show that while the desire for a baby is the dominant drive, couples' views revealed more nuanced and complex considerations in the decision-making process. It was clear that the desire to have a baby influenced couples' decision-making and that they saw freezing as 'part of the process'. However, there were confusions associated with the term 'freezing' related to concerns about the safety of the procedure. Despite being given written information, couples were confused about the practical aspects of embryo freezing, which suggests they were preoccupied with the immediate demands of IVF. Couples expressed ethical conflicts about freezing 'babies'. We hope the findings from this study will inform clinicians and assist them in providing support to couples confronted with this difficult decision-making.

  19. Bulls grazing Kentucky 31 tall fescue exhibit impaired growth, semen quality, and decreased semen freezing potential

    Science.gov (United States)

    Serum prolactin (PRL) and testosterone concentrations, body weight, body composition, semen quality, and semen freezing potential for bulls grazing the toxic tall fescue (Lolium arundinaceum [Schreb.] Darbysh. ¼ Schedonorous arundinaceum [Schreb.] Dumort.) cultivar Kentucky 31 (E+) compared with a n...

  20. Generalized enthalpy model of a high-pressure shift freezing process

    KAUST Repository

    Smith, N. A. S.

    2012-05-02

    High-pressure freezing processes are a novel emerging technology in food processing, offering significant improvements to the quality of frozen foods. To be able to simulate plateau times and thermal history under different conditions, in this work, we present a generalized enthalpy model of the high-pressure shift freezing process. The model includes the effects of pressure on conservation of enthalpy and incorporates the freezing point depression of non-dilute food samples. In addition, the significant heat-transfer effects of convection in the pressurizing medium are accounted for by solving the two-dimensional Navier-Stokes equations. We run the model for several numerical tests where the food sample is agar gel, and find good agreement with experimental data from the literature. © 2012 The Royal Society.

  1. Does freeze-all policy affect IVF outcomes in poor responders?

    Science.gov (United States)

    Roque, Matheus; Valle, Marcello; Sampaio, Marcos; Geber, Selmo

    2017-12-27

    To evaluate whether the freeze-all strategy affects in vitro fertilization (IVF) outcomes in poor ovarian responders following the Bologna criteria. We performed a retrospective cohort study conducted between January 2012 and December 2016. A total of 433 poor responders (per the Bologna criteria) fulfilled the inclusion/exclusion criteria and were included in the study, with 277 patients included in the fresh group and 156 in the freeze-all group. All patients were submitted to controlled ovarian stimulation (COS) with a gonadotropin-releasing hormone antagonist protocol and cleavage-stage embryo transfer (ET). The main outcome measure was ongoing pregnancy rate. Secondary outcomes included implantation and clinical pregnancy rates. The freeze-all strategy was implemented when the progesterone serum level was >1.5 ng/mL on the trigger day, when the endometrium was <7 mm on the trigger day, or as a patient preference. Patients with previous failed fresh embryo transfer were also submitted to fresh or freeze-all strategy considering the indications mentioned above. The patients' mean age in the freeze-all group was 39.5±3.6 years, while that of patients in the fresh group was 39.7±3.8 years (P=0.54). The mean number of embryos transferred (nET) was 1.53±0.6 and 1.60±0.6 (P=0.12) in the freeze-all and fresh groups, respectively. Ongoing pregnancy rates did not significantly differ between the freeze-all and fresh groups (9.6% versus 10.1%, respectively; Relative Risk [RR]: 0.95; 95% CI: 0.52-1.73), nor did the clinical pregnancy rates (14.1% versus 13.7%, respectively; RR: 1.03; 95% CI: 0.63-1.76). Implantation rates were 9.6% and 9.8% (P=0.82) in the freeze-all and fresh groups, respectively. The logistic regression analysis (including age, antral follicle count [AFC], the number of retrieved oocytes, the number of mature oocytes, nET, and fresh versus freeze-all strategy) indicated that age (P<0.001) and the nET (P=0.039) were the only independent variables

  2. Microbial analysis and survey test of gamma-irradiated freeze-dried fruits for patient's food

    International Nuclear Information System (INIS)

    Park, Jae-Nam; Sung, Nak-Yun; Byun, Eui-Hong; Byun, Eui-Baek; Song, Beom-Seok; Kim, Jae-Hun; Lee, Kyung-A; Son, Eun-Joo; Lyu, Eun-Soon

    2015-01-01

    This study examined the microbiological and organoleptic qualities of gamma-irradiated freeze-dried apples, pears, strawberries, pineapples, and grapes, and evaluated the organoleptic acceptability of the sterilized freeze-dried fruits for hospitalized patients. The freeze-dried fruits were gamma-irradiated at 0, 1, 2, 3, 4, 5, 10, 12, and 15 kGy, and their quality was evaluated. Microorganisms were not detected in apples after 1 kGy, in strawberries and pears after 4 kGy, in pineapples after 5 kGy, and in grapes after 12 kGy of gamma irradiation. The overall acceptance score, of the irradiated freeze-dried fruits on a 7-point scale at the sterilization doses was 5.5, 4.2, 4.0, 4.1, and 5.1 points for apples, strawberries, pears, pineapples, and grapes, respectively. The sensory survey of the hospitalized cancer patients (N=102) resulted in scores of 3.8, 3.7, 3.9, 3.9, and 3.7 on a 5-point scale for the gamma-irradiated freeze-dried apples, strawberries, pears, pineapples, and grapes, respectively. The results suggest that freeze-dried fruits can be sterilized with a dose of 5 kGy, except for grapes, which require a dose of 12 kGy, and that the organoleptic quality of the fruits is acceptable to immuno-compromised patients. However, to clarify the microbiological quality and safety of freeze-dried fruits should be verified by plating for both aerobic and anaerobic microorganisms. - Highlights: • Dried fruits can be sterilized with a dose of 12 kGy. • Sensory survey of the hospitalized cancer patients (N=102). • Sensory quality of dried fruits is acceptable to cancer patients

  3. Freezing during tapping tasks in patients with advanced Parkinson's disease and freezing of gait.

    Science.gov (United States)

    Delval, Arnaud; Defebvre, Luc; Tard, Céline

    2017-01-01

    Parkinson's disease patients with freezing of gait also experience sudden motor blocks (freezing) during other repetitive motor tasks. We assessed the proportion of patients with advanced PD and freezing of gait who also displayed segmental "freezing" in tapping tasks. Fifteen Parkinson's disease patients with freezing of gait were assessed. Freezing of gait was evaluated using a standardized gait trajectory with the usual triggers. Patients performed repetitive tapping movements (as described in the MDS-UPDRS task) with the hands or the feet in the presence or absence of a metronome set to 4 Hz. Movements were recorded with a video motion system. The primary endpoint was the occurrence of segmental freezing in these tapping tasks. The secondary endpoints were (i) the relationship between segmental episodic phenomena and FoG severity, and (ii) the reliability of the measurements. For the upper limbs, freezing was observed more frequently with a metronome (21% of trials) than without a metronome (5%). For the lower limbs, the incidence of freezing was higher than for the upper limbs, and was again observed more frequently in the presence of an auditory cue (47%) than in its absence (14%). Although freezing of the lower limbs was easily assessed during an MDS-UPDRS task with a metronome, it was not correlated with the severity of freezing of gait (as evaluated during a standardized gait trajectory). Only this latter was a reliable measurement in patients with advanced Parkinson's disease.

  4. Freezing of Water Droplet due to Evaporation

    Science.gov (United States)

    Satoh, Isao; Fushinobu, Kazuyoshi; Hashimoto, Yu

    In this study, the feasibility of cooling/freezing of phase change.. materials(PCMs) due to evaporation for cold storage systems was experimentally examined. A pure water was used as the test PCM, since the latent heat due to evaporation of water is about 7 times larger than that due to freezing. A water droplet, the diameter of which was 1-4 mm, was suspended in a test cell by a fine metal wire (O. D.= 100μm),and the cell was suddenly evacuated up to the pressure lower than the triple-point pressure of water, so as to enhance the evaporation from the water surface. Temperature of the droplet was measured by a thermocouple, and the cooling/freezing behavior and the temperature profile of the droplet surface were captured by using a video camera and an IR thermo-camera, respectively. The obtained results showed that the water droplet in the evacuated cell is effectively cooled by the evaporation of water itself, and is frozen within a few seconds through remarkable supercooling state. When the initial temperature of the droplet is slightly higher than the room temperature, boiling phenomena occur in the droplet simultaneously with the freezing due to evaporation. Under such conditions, it was shown that the degree of supercooling of the droplet is reduced by the bubbles generated in the droplet.

  5. Evaluation of Short-Term Changes in Serum Creatinine Level as a Meaningful End Point in Randomized Clinical Trials.

    Science.gov (United States)

    Coca, Steven G; Zabetian, Azadeh; Ferket, Bart S; Zhou, Jing; Testani, Jeffrey M; Garg, Amit X; Parikh, Chirag R

    2016-08-01

    Observational studies have shown that acute change in kidney function (specifically, AKI) is a strong risk factor for poor outcomes. Thus, the outcome of acute change in serum creatinine level, regardless of underlying biology or etiology, is frequently used in clinical trials as both efficacy and safety end points. We performed a meta-analysis of clinical trials to quantify the relationship between positive or negative short-term effects of interventions on change in serum creatinine level and more meaningful clinical outcomes. After a thorough literature search, we included 14 randomized trials of interventions that altered risk for an acute increase in serum creatinine level and had reported between-group differences in CKD and/or mortality rate ≥3 months after randomization. Seven trials assessed interventions that, compared with placebo, increased risk of acute elevation in serum creatinine level (pooled relative risk, 1.52; 95% confidence interval, 1.22 to 1.89), and seven trials assessed interventions that, compared with placebo, reduced risk of acute elevation in serum creatinine level (pooled relative risk, 0.57; 95% confidence interval, 0.44 to 0.74). However, pooled risks for CKD and mortality associated with interventions did not differ from those with placebo in either group. In conclusion, several interventions that affect risk of acute, mild to moderate, often temporary elevation in serum creatinine level in placebo-controlled randomized trials showed no appreciable effect on CKD or mortality months later, raising questions about the value of using small to moderate changes in serum creatinine level as end points in clinical trials. Copyright © 2016 by the American Society of Nephrology.

  6. Using Power Ultrasound to Accelerate Food Freezing Processes: Effects on Freezing Efficiency and Food Microstructure.

    Science.gov (United States)

    Zhang, Peizhi; Zhu, Zhiwei; Sun, Da-Wen

    2018-05-31

    Freezing is an effective way of food preservation. However, traditional freezing methods have the disadvantages of low freezing efficiency and generation of large ice crystals, leading to possible damage of food quality. Power ultrasound assisted freezing as a novel technique can effectively reduce the adverse effects during freezing process. This paper gives an overview on recent researches of power ultrasound technique to accelerate the food freezing processes and illustrates the main principles of power ultrasound assisted freezing. The effects of power ultrasound on liquid food, model solid food as well as fruit and vegetables are discussed, respectively, from the aspects of increasing freezing rate and improving microstructure. It is shown that ultrasound assisted freezing can effectively improve the freezing efficiency and promote the formation of small and evenly distributed ice crystals, resulting in better food quality. Different inherent properties of food samples affect the effectiveness of ultrasound application and optimum ultrasound parameters depend on the nature of the samples. The application of ultrasound to the food industry is more likely on certain types of food products and more efforts are still needed to realize the industrial translation of laboratory results.

  7. A comparison of freezing-damage during isochoric and isobaric freezing of the potato

    OpenAIRE

    Lyu, Chenang; Nastase, Gabriel; Ukpai, Gideon; Serban, Alexandru; Rubinsky, Boris

    2017-01-01

    Background Freezing is commonly used for food preservation. It is usually done under constant atmospheric pressure (isobaric). While extending the life of the produce, isobaric freezing has detrimental effects. It causes loss of food weight and changes in food quality. Using thermodynamic analysis, we have developed a theoretical model of the process of freezing in a constant volume system (isochoric). The mathematical model suggests that the detrimental effects associated with isobaric freez...

  8. Durability of cracked fibre reinforced concrete exposed to freeze-thaw and deicing salt

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1998-01-01

    Durability studies are carried out by subjecting FRC-beams to combined mechanical and environmental load. Mechanical load is obtained by subjecting beams to 4-point bending until a predefined crack width is reached. Specimens sawn from the beams after unloading are exposed to freeze-thaw and deic......Durability studies are carried out by subjecting FRC-beams to combined mechanical and environmental load. Mechanical load is obtained by subjecting beams to 4-point bending until a predefined crack width is reached. Specimens sawn from the beams after unloading are exposed to freeze-thaw...... and deicing salt. The concrete has a water-powder ratio of 0.38 including both fly ash and silica fume. Both steel fibres (ZP, 0.4 vol%) and polypropylene fibres (PP, 1 vol%) are used as well as main reinforcement. The freeze-thaw test emphasizes the need for a critical evaluation of the mix design and mixing...

  9. A theoretical extension of the soil freezing curve paradigm

    Science.gov (United States)

    Amiri, Erfan A.; Craig, James R.; Kurylyk, Barret L.

    2018-01-01

    Numerical models of permafrost evolution in porous media typically rely upon a smooth continuous relation between pore ice saturation and sub-freezing temperature, rather than the abrupt phase change that occurs in pure media. Soil scientists have known for decades that this function, known as the soil freezing curve (SFC), is related to the soil water characteristic curve (SWCC) for unfrozen soils due to the analogous capillary and sorptive effects experienced during both soil freezing and drying. Herein we demonstrate that other factors beyond the SFC-SWCC relationship can influence the potential range over which pore water phase change occurs. In particular, we provide a theoretical extension for the functional form of the SFC based upon the presence of spatial heterogeneity in both soil thermal conductivity and the freezing point depression of water. We infer the functional form of the SFC from many abrupt-interface 1-D numerical simulations of heterogeneous systems with prescribed statistical distributions of water and soil properties. The proposed SFC paradigm extension has the appealing features that it (1) is determinable from measurable soil and water properties, (2) collapses into an abrupt phase transition for homogeneous media, (3) describes a wide range of heterogeneity within a single functional expression, and (4) replicates the observed hysteretic behavior of freeze-thaw cycles in soils.

  10. Freeze dried blood and development of an artificial diet for blood feeding arthropods

    International Nuclear Information System (INIS)

    DeLoach, J.R.; Spates, G.E.; Kapatsa, G.M.; Sheffield, C.L.; Kabayo, J.P.

    1990-01-01

    The goals of the research were to determine the biochemical differences between freeze dried bovine and porcine blood relative to their nutritional value to Glossina palpalis palpalis and Stomoxys calcitrans and to develop an artificial diet for mass rearing these flies. Freeze dried bovine and porcine blood were found to differ in their amino acid content; total dietary lipids did not significantly differ, but some notable exceptions were found in fatty acid content. Both sonication and addition of foetal bovine serum to freeze dried bovine blood improved its nutritional value for G. p. palpalis. A two component, semi-defined artificial diet was developed for G. p. palpalis and S. calcitrans. The College Station diet consisted of lipid contaminated bovine haemoglobin (BHb) and bovine serum albumin (BSA). To conduct dietary deletion tests, a process was developed for preparing large quantities of ultrapure lipid free bovine haemoglobin. S. calcitrans fed on lipid free BHb plus BSA had zero fecundity. Lipids were re-added to the protein diet in three forms: (1) lipid contaminated BHb, (2) pure erythrocyte ghosts, and (3) pure lipids. It was found that membrane lipid from the erythrocyte is required by S. calcitrans. A defined artificial diet consisting of lipid free BHb, BSA, sphingomyelin, phosphatidyl ethanolamine, phosphatidyl serine and cholesterol gave normal adult survival, as well as near normal fecundity and percentage egg hatch for S. calcitrans. Knowing the identity of the lipids, it is now possible to prepare dietary formulations to alleviate dependency on the blood proteins BHb and BSA. (author). 34 refs, 1 fig., 15 tabs

  11. Summer freezing resistance: a critical filter for plant community assemblies in Mediterranean high mountains

    Directory of Open Access Journals (Sweden)

    David Sánchez Pescador

    2016-02-01

    Full Text Available Assessing freezing community response and whether freezing resistance is related to other functional traits is essential for understanding alpine community assemblages, particularly in Mediterranean environments where plants are exposed to freezing temperatures and summer droughts. Thus, we characterized the leaf freezing resistance of 42 plant species in 38 plots at Sierra de Guadarrama (Spain by measuring their ice nucleation temperature, freezing point (FP, and low-temperature damage (LT50, as well as determining their freezing resistance mechanisms (i.e., tolerance or avoidance. The community response to freezing was estimated for each plot as community weighted means (CWMs and functional diversity, and we assessed their relative importance with altitude. We established the relationships between freezing resistance, growth forms, and four key plant functional traits (i.e., plant height, specific leaf area, leaf dry matter content, and seed mass. There was a wide range of freezing resistance responses and more than in other alpine habitats. At the community level, the CWMs of FP and LT50 responded negatively to altitude, whereas the functional diversity of both traits increased with altitude. The proportion of freezing-tolerant species also increased with altitude. The ranges of FP and LT50 varied among growth forms, and only the leaf dry matter content correlated negatively with freezing-resistance traits. Summer freezing events represent important abiotic filters for assemblies of Mediterranean high mountain communities, as suggested by the CWMs. However, a concomitant summer drought constraint may also explain the high freezing resistance of species that thrive in these areas and the lower functional diversity of freezing resistance traits at lower altitudes. Leaves with high dry matter contents may maintain turgor at lower water potential and enhance drought tolerance in parallel to freezing resistance. This adaptation to drought seems to

  12. Effect of baking and steaming on physicochemical and thermal properties of sweet potato puree preserved by freezing and freeze-drying

    Directory of Open Access Journals (Sweden)

    Bernarda Svrakačić

    2016-01-01

    Full Text Available Thermal treatments could be one of the hurdles in applications of sweet potato purees for food different products formulation. Sweet potato purees (SPP were prepared from raw, baked and steamed roots and they were preserved by freezing and freeze-drying. The effects of baking and steaming on thermal properties (melting temperature-Tm, melting transition energy - ΔH, and glass transition temperatures - Tg of sweet potato (cultivar Beauregard, were measured by means of a Differential scanning calorimetry (DSC. The SPP made from baked roots had higher total and soluble solids (20.32 and 18.95%, respectively than SPP made from raw and steamed roots. It can be also noticed that starch content was reduced by steaming and baking which reflected on amount of total and reducing sugars. The increase of reducing sugars level in baked SPP for 3.78% and steamed for 0.86% SPP was the result of yielding the maltose. The chemical changes of SPP also influenced the thermal behavior such that SPP prepared from baked sweet potato roots had the lowest initial freezing point (-2.80 °C followed by SPP prepared from steamed (-2.63 °C and raw (-0.71 °C roots. The highest energy for melting (transition was needed for SPP prepared from raw potato roots followed by steamed and baked roots, -103.79, -103.63, and -102.90 J/g, respectively. The glass transition in freeze-dried SPP prepared from raw roots was not detected. However, in the freeze-dried SPP prepared from baked and steamed roots the glass transition was detected in the range of 39 and 42 °C but with no significant difference (p > 0.05.

  13. Reliable clinical serum analysis with reusable electrochemical sensor: Toward point-of-care measurement of the antipsychotic medication clozapine.

    Science.gov (United States)

    Kang, Mijeong; Kim, Eunkyoung; Winkler, Thomas E; Banis, George; Liu, Yi; Kitchen, Christopher A; Kelly, Deanna L; Ghodssi, Reza; Payne, Gregory F

    2017-09-15

    Clozapine is one of the most promising medications for managing schizophrenia but it is under-utilized because of the challenges of maintaining serum levels in a safe therapeutic range (1-3μM). Timely measurement of serum clozapine levels has been identified as a barrier to the broader use of clozapine, which is however challenging due to the complexity of serum samples. We demonstrate a robust and reusable electrochemical sensor with graphene-chitosan composite for rapidly measuring serum levels of clozapine. Our electrochemical measurements in clinical serum from clozapine-treated and clozapine-untreated schizophrenia groups are well correlated to centralized laboratory analysis for the readily detected uric acid and for the clozapine which is present at 100-fold lower concentration. The benefits of our electrochemical measurement approach for serum clozapine monitoring are: (i) rapid measurement (≈20min) without serum pretreatment; (ii) appropriate selectivity and sensitivity (limit of detection 0.7μM); (iii) reusability of an electrode over several weeks; and (iv) rapid reliability testing to detect common error-causing problems. This simple and rapid electrochemical approach for serum clozapine measurements should provide clinicians with the timely point-of-care information required to adjust dosages and personalize the management of schizophrenia. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. The influence of freezing rates on bovine pericardium tissue Freeze-drying

    Directory of Open Access Journals (Sweden)

    Camila Figueiredo Borgognoni

    2009-12-01

    Full Text Available The bovine pericardium has been used as biomaterial in developing bioprostheses. Freeze-drying is a drying process that could be used for heart valve's preservation. The maintenance of the characteristics of the biomaterial is important for a good heart valve performance. This paper describes the initial step in the development of a bovine pericardium tissue freeze-drying to be used in heart valves. Freeze-drying involves three steps: freezing, primary drying and secondary drying. The freezing step influences the ice crystal size and, consequently, the primary and secondary drying stages. The aim of this work was to investigate the influence of freezing rates on the bovine pericardium tissue freeze-drying parameters. The glass transition temperature and the structural behaviour of the lyophilized tissues were determined as also primary and secondary drying time. The slow freezing with thermal treatment presented better results than the other freeze-drying protocols.O pericárdio bovino é um material utilizado na fabricação de biopróteses. A liofilização é um método de secagem que vem sendo estudado para a conservação de válvulas cardíacas. A preservação das características do biomaterial é de fundamental importância no bom funcionamento das válvulas. Este artigo é a primeira etapa do desenvolvimento do ciclo de liofilização do pericárdio bovino. Liofilização é o processo de secagem no qual a água é removida do material congelado por sublimação e desorção da água incongelável, sob pressão reduzida. O congelamento influencia o tamanho do cristal de gelo e, consequentemente, a secagem primária e secundária. O objetivo deste estudo foi verificar a influência das taxas de congelamento nos parâmetros de liofilização do pericárdio bovino. Determinou-se a temperatura de transição vítrea e o comportamento estrutural do pericárdio bovino liofilizado. Determinou-se o tempo da secagem primária e secundária. O

  15. Freezing of bentonite. Experimental studies and theoretical considerations

    Energy Technology Data Exchange (ETDEWEB)

    Birgersson, Martin; Karnland, Ola; Nilsson, Ulf (Clay Technology AB, Lund (Sweden))

    2010-01-15

    During its lifetime, a KBS-3 repository will be subject to various ambient temperatures. Backfilled tunnels, shafts and investigation bore holes closest to ground level will experience periods of temperature below 0 deg C. From a safety assessment perspective, it is therefore essential to understand the behavior of compacted bentonite below 0 deg C. A theoretical framework for predicting the pressure response in compacted water saturated bentonite due to temperature changes has been developed based on thermodynamics and a single pore-type. This model predicts an approximately linear temperature dependence of swelling pressure P{sub s}(w,DELTAT) = P{sub s}(w,0 deg C) + DELTAs(w)DELTAT/nu{sub clay}(w) where DELTAT denotes a temperature difference from 0 deg C, DELTAs(w) is the difference in partial molar entropy between clay water and bulk water, nu{sub clay} (w) is the partial molar volume of the clay water and w denotes the water/solid mass ratio of the clay. As bulk water changes phase at 0 deg C, DELTAs(w) has a different value dependent on whether DELTAT is negative or positive. Above 0 deg C DELTAs(w) is a small value for all relevant densities which means that the pressure response due to temperature changes is small. A further consequence of this fact is that DELTAs(w) is a large positive number below 0 deg C when the external water phase is transformed to ice. Consequently, the model predicts a large drop of swelling pressure with temperature below 0 deg C, in the order of 1.2 MPa/deg C. Specifically, the swelling pressure is zero at a certain (negative) temperature T{sub C}. T{sub C} also quantifies the freezing point of the bentonite sample under consideration, as ice formation in the bentonite does not occur until swelling pressure is lost. A large set of laboratory tests have been performed where fully water saturated samples of bentonites have been exposed to temperatures in the range -10 deg C to +25 deg C. The swelling pressure response has been

  16. Effect of storage duration on cytokine stability in human serum and plasma.

    Science.gov (United States)

    Vincent, Fabien B; Nim, Hieu T; Lee, Jacinta P W; Morand, Eric F; Harris, James

    2018-06-14

    Quantification of analytes such as cytokines in serum samples is intrinsic to translational research in immune diseases. Optimising pre-analytical conditions is critical for ensuring study quality, including evaluation of cytokine stability. We aimed to evaluate the effect on cytokine stability of storage duration prior to freezing of serum, and compare to plasma samples obtained from patients with systemic lupus erythematosus (SLE). Protein stability was analysed by simultaneously quantifying 18 analytes using a custom multi-analyte profile in SLE patient serum and plasma samples that had been prospectively stored at 4 °C for pre-determined periods between 0 and 30 days, prior to freezing. Six analytes were excluded from analysis, because most tested samples were above or below the limit of detection. Amongst the 12 analysed proteins, 11 did not show significant signal degradation. Significant signal degradation was observed from the fourth day of storage for a single analyte, CCL19. Proteins levels were more stable in unseparated serum compared to plasma for most analytes, with the exception of IL-37 which appears slightly more stable in plasma. Based on this, a maximum 3 days of storage at 4 °C for unseparated serum samples is recommended for biobanked samples intended for cytokine analysis in studies of human immune disease. Copyright © 2018 Elsevier Ltd. All rights reserved.

  17. Objective video quality assessment method for freeze distortion based on freeze aggregation

    Science.gov (United States)

    Watanabe, Keishiro; Okamoto, Jun; Kurita, Takaaki

    2006-01-01

    With the development of the broadband network, video communications such as videophone, video distribution, and IPTV services are beginning to become common. In order to provide these services appropriately, we must manage them based on subjective video quality, in addition to designing a network system based on it. Currently, subjective quality assessment is the main method used to quantify video quality. However, it is time-consuming and expensive. Therefore, we need an objective quality assessment technology that can estimate video quality from video characteristics effectively. Video degradation can be categorized into two types: spatial and temporal. Objective quality assessment methods for spatial degradation have been studied extensively, but methods for temporal degradation have hardly been examined even though it occurs frequently due to network degradation and has a large impact on subjective quality. In this paper, we propose an objective quality assessment method for temporal degradation. Our approach is to aggregate multiple freeze distortions into an equivalent freeze distortion and then derive the objective video quality from the equivalent freeze distortion. Specifically, our method considers the total length of all freeze distortions in a video sequence as the length of the equivalent single freeze distortion. In addition, we propose a method using the perceptual characteristics of short freeze distortions. We verified that our method can estimate the objective video quality well within the deviation of subjective video quality.

  18. Effects of various freezing containers for vitrification freezing on mouse oogenesis.

    Science.gov (United States)

    Kim, Ji Chul; Kim, Jae Myeoung; Seo, Byoung Boo

    2016-01-01

    In the present study, various freezing containers were tested for mouse embryos of respective developmental stages; embryos were vitrified and then their survival rate and developmental rate were monitored. Mouse two cell, 8 cell, and blastula stage embryos underwent vitrification freezing-thawing and then their recovery rate, survival rate, development rate, and hatching rate were investigated. EM-grid, OPS, and cryo-loop were utilized for vitrification freezing-thawing of mouse embryos. It was found that recovery rate and survival rate were higher in the group of cryo-loop compared to those of EM-grid (p containers on vitrified embryos of respective developmental stages; it was demonstrated that higher developmental rate was shown in more progressed (or developed) embryos with more blastomeres. There was however, no difference in embryonic development rate was shown amongst containers. Taken together, further additional studies are warranted with regards to 1) manipulation techniques of embryos for various vitrification freezing containers and 2) preventive measures against contamination via liquid nitrogen.

  19. Plasma and serum lipidomics of healthy white adults shows characteristic profiles by subjects' gender and age.

    Directory of Open Access Journals (Sweden)

    Masaki Ishikawa

    Full Text Available Blood is a commonly used biofluid for biomarker discovery. Although blood lipid metabolites are considered to be potential biomarker candidates, their fundamental properties are not well characterized. We aimed to (1 investigate the matrix type (serum vs. plasma that may be preferable for lipid biomarker exploration, (2 elucidate age- and gender-associated differences in lipid metabolite levels, and (3 examine the stability of lipid metabolites in matrix samples subjected to repeated freeze-thaw cycles. Using liquid chromatography-mass spectrometry, we performed lipidomic analyses for fasting plasma and serum samples for four groups (15 subjects/group of young and elderly (25-34 and 55-64 years old, respectively males and females and for an additional aliquot of samples from young males, which were subjected to repeated freeze-thaw cycles. Lysophosphatidylcholine and diacylglycerol levels were higher in serum than in plasma samples, suggesting that the clotting process influences serum lipid metabolite levels. Gender-associated differences highlighted that the levels of many sphingomyelin species were significantly higher in females than in males, irrespective of age and matrix (plasma and serum. Age-associated differences were more prominent in females than in males, and in both matrices, levels of many triacylglycerols were significantly higher in elderly females than in young females. Plasma and serum levels of most lipid metabolites were reduced by freeze-thawing. Our results indicate that plasma is an optimal matrix for exploring lipid biomarkers because it represents the original properties of an individual's blood sample. In addition, the levels of some blood lipid species of healthy adults showed gender- and age-associated differences; thus, this should be considered during biomarker exploration and its application in diagnostics. Our fundamental findings on sample selection and handling procedures for measuring blood lipid metabolites

  20. Monte Carlo simulation of the OCP freezing transition

    International Nuclear Information System (INIS)

    DeWitt, H.E.; Slattery, W.L.; Yang, Juxing

    1992-09-01

    The One Component Plasma (OCP) in three dimensions is a system of classical point charges moving in a fixed uniform neutralizing background. In nature the OCP is a rough approximation of the conditions in a white dwarf star in which one has fully ionized nuclei such as carbon, oxygen, and smaller amounts of heavier elements up to iron all moving in a nearly uniform background provided by relativistically degenerate electrons. The OCP is also a mathematical limiting model for a non-neutral plasma of ions in a Penning trap and cooled to strongly coupled conditions. Similarly, a collection of charge colloidal suspensions in water can exhibit the Coulomb freezing behavior of the OCP. A single dimensionless parameter, Γ is sufficient to describe the system. For very weak coupling, Γ much-lt 1, the thermodynamic properties of the OCP are given rigorously by the Debye-Huckel theory. This paper reports on Monte Carlo simulation of the freezing of the OCP from a random start for particle numbers ranging from 500 to 2000. In one case the authors obtained a perfect bcc lattice, but in most cases the final state would be an imperfect crystal or two different microcrystals, fcc and bcc, growing into each other. With a cluster analysis program the authors looked at the formation of nucleating clusters, and followed the actual freezing process. Roughly 80 particles are needed in a cluster before it starts to grow rapidly and freeze

  1. The value of a freeze

    International Nuclear Information System (INIS)

    Bethe, H.A.; Long, F.A.

    1988-01-01

    This paper reports on the rapid increase in public support for a nuclear-freeze agreement---that is, a mutual freeze on the testing, production and further deployment of nuclear weapons---which has been a remarkable political phenomenon. In less than a year, support has grown from a few volunteers collecting signatures on petitions to a congressional vote in which supporters of a freeze very nearly prevailed. This fall, eight states and the District of Columbia will vote on freeze referendums. Already Wisconsin voters have overwhelmingly voted yes in such a referendum. There are many reasons for this strong support for a freeze, including fear of nuclear war, resistance to high levels of military spending and opposition to particular military policies of the Reagan administration. But to most supporters, the chief purpose of a freeze is simple: it is to help stop an immense, continuing, dangerous and incredibly costly arms race between the two superpowers

  2. Seeing fearful body language rapidly freezes the observer's motor cortex

    NARCIS (Netherlands)

    Borgomaneri, Sara; Vitale, Francesca; Gazzola, V.; Avenanti, Alessio

    Fearful body language is a salient signal alerting the observer to the presence of a potential threat in the surrounding environment. Although detecting potential threats may trigger an immediate reduction of motor output in animals (i.e., freezing behavior), it is unclear at what point in time

  3. Seeing fearful body language rapidly freezes the observer's motor cortex

    NARCIS (Netherlands)

    Borgomaneri, S.; Vitale, F.; Gazzola, V.; Avenanti, A.

    2015-01-01

    Fearful body language is a salient signal alerting the observer to the presence of a potential threat in the surrounding environment. Although detecting potential threats may trigger an immediate reduction of motor output in animals (i.e., freezing behavior), it is unclear at what point in time

  4. The Freezing Bomb

    Science.gov (United States)

    Mills, Allan

    2010-01-01

    The extreme pressures that are generated when water freezes were traditionally demonstrated by sealing a small volume in a massive cast iron "bomb" and then surrounding it with a freezing mixture of ice and salt. This vessel would dramatically fail by brittle fracture, but no quantitative measurement of bursting pressure was available. Calculation…

  5. Fundamental Technical Elements of Freeze-fracture/Freeze-etch in Biological Electron Microscopy

    Science.gov (United States)

    Freeze-fracture/freeze-etch describes a process whereby specimens, typically biological or nanomaterial in nature, are frozen, fractured, and replicated to generate a carbon/platinum "cast" intended for examination by transmission electron microscopy. Specimens are subjected to u...

  6. Threshold temperatures mediate the impact of reduced snow cover on overwintering freeze-tolerant caterpillars

    Science.gov (United States)

    Marshall, Katie E.; Sinclair, Brent J.

    2012-01-01

    Decreases in snow cover due to climate change could alter the energetics and physiology of ectothermic animals that overwinter beneath snow, yet how snow cover interacts with physiological thresholds is unknown. We applied numerical simulation of overwintering metabolic rates coupled with field validation to determine the importance of snow cover and freezing to the overwintering lipid consumption of the freeze-tolerant Arctiid caterpillar Pyrrharctia isabella. Caterpillars that overwintered above the snow experienced mean temperatures 1.3°C lower than those below snow and consumed 18.36 mg less lipid of a total 68.97-mg reserve. Simulations showed that linear temperature effects on metabolic rate accounted for only 30% of the difference in lipid consumption. When metabolic suppression by freezing was included, 93% of the difference between animals that overwintered above and below snow was explained. Our results were robust to differences in temperature sensitivity of metabolic rate, changes in freezing point, and the magnitude of metabolic suppression by freezing. The majority of the energy savings was caused by the non-continuous reduction in metabolic rate due to freezing, the first example of the importance of temperature thresholds in the lipid use of overwintering insects.

  7. Impregnation of leather during "freeze-drying"

    DEFF Research Database (Denmark)

    Storch, Mikkel; Vestergaard Poulsen Sommer, Dorte; Hovmand, Ida

    2016-01-01

    Freeze-drying is a recognized method for the preservation of waterlogged objects. Naturally, freeze-drying has also been used for waterlogged archaeological leather often after treatment with Na2.EDTA and impregnation with PEG; but the treated leather sometimes suffers from “excessive drying......” becoming too stiff and brittle. The aim of this study was to examine the effect of a conventional freeze-drying method against an alternative freeze-drying method that preserves the natural moisture content of the leather. Both new and archaeological waterlogged leather were included in the study...... suggest that the process which takes place within the leather during the freeze-drying in not actual freeze-drying, but rather a sophisticated way of distributing the impregnating agent. The pure ice phase freezes out, but the impregnating agent remains liquid as the temperature does not become low enough...

  8. Building the Method to Determine the Rate of Freezing Water in Penaeus monodon of the Freezing Process

    OpenAIRE

    Nguyen Tan Dzung; Trinh Van Dzung; Tran Duc Ba

    2012-01-01

    The method of determination the rate of freezing water in Penaeus monodon of freezing process was established on base the equation of energy balance in warming up process Penaeus monodon after freezing to determine specific heat of Penaeus monodon. The result obtained was built the mathematical model (19) to determine the rate of freezing water according to the freezing temperature of Penaeus monodon. The results indicated that when water was completely frozen (ω = 1 or 100%), the optimal fre...

  9. Advantages of liquid nitrogen freezing of Penaeus monodon over conventional plate freezing

    OpenAIRE

    Chakrabarti, R.; Chaudhury, D.R.

    1987-01-01

    Liquid nitrogen frozen products are biochemically and organoleptically superior to conventional plate frozen products but beneficial effect of liquid nitrogen freezing over conventional plate freezing can exist only up to 59 days at a commercial storage temperature of -18°C.

  10. Polymerization with freezing

    International Nuclear Information System (INIS)

    Ben-Naim, E; Krapivsky, P L

    2005-01-01

    Irreversible aggregation processes involving reactive and frozen clusters are investigated using the rate equation approach. In aggregation events, two clusters join irreversibly to form a larger cluster; additionally, reactive clusters may spontaneously freeze. Frozen clusters do not participate in merger events. Generally, freezing controls the nature of the aggregation process, as demonstrated by the final distribution of frozen clusters. The cluster mass distribution has a power-law tail, F k ∼k -γ , when the freezing process is sufficiently slow. Different exponents, γ = 1 and 3, are found for the constant and the product aggregation rates, respectively. For the latter case, the standard polymerization model, either no gels, or a single gel, or even multiple gels, may be produced

  11. Data from the analytical performance of the Abaxis Piccolo Xpress point of care analyzer in whole blood, serum, and plasma

    Directory of Open Access Journals (Sweden)

    Kazunori Murata

    2018-02-01

    Full Text Available The objective of this study was to examine the analytical performance of 14 comprehensive metabolic panel analytes on the Abaxis Piccolo Xpress® Point of Care analyzer in serum, plasma, and whole blood. A method comparison was performed on all three specimen types intended for use on the Piccolo Xpress®: serum, heparinized plasma, and whole blood. This data is also presented in Murata et al. (2015 [1]. This article includes the actual Bland-Altman bias plots of the difference in results obtained for analytes in the comprehensive metabolic panel from the Abaxis Piccolo Xpress and the comparison instrument, the Ortho Vitros. Keywords: Clinical chemistry, Point-of care testing

  12. Generalized structural theory of freezing

    International Nuclear Information System (INIS)

    Yussouff, M.

    1980-10-01

    The first-principles order parameter theory of freezing, proposed in an earlier work, has been successful in yielding quantitative agreement with known freezing parameters for monoatomic liquids forming solids with one atom per unit cell. A generalization of this theory is presented here to include the effects of a basis set of many atoms per unit cell. The basic equations get modified by the 'density structure factors' fsub(i) which arise from the density variations within the unit cell. Calculations are presented for the important case of monoatomic liquids freezing into hexagonal close packed solids. It is concluded that all freezing transitions can be described by using structural correlations in the liquid instead of the pair potential; and that the three body correlations are important in deciding the type of solid formed after freezing. (author)

  13. Influence of common preanalytical variations on the metabolic profile of serum samples in biobanks

    Energy Technology Data Exchange (ETDEWEB)

    Fliniaux, Ophelie [University of Picardie Jules Verne, Laboratoire de Phytotechnologie EA 3900-BioPI (France); Gaillard, Gwenaelle [Biobanque de Picardie (France); Lion, Antoine [University of Picardie Jules Verne, Laboratoire de Phytotechnologie EA 3900-BioPI (France); Cailleu, Dominique [Batiment Serres-Transfert, rue de Mai/rue Dallery, Plateforme Analytique (France); Mesnard, Francois, E-mail: francois.mesnard@u-picardie.fr [University of Picardie Jules Verne, Laboratoire de Phytotechnologie EA 3900-BioPI (France); Betsou, Fotini [Integrated Biobank of Luxembourg (Luxembourg)

    2011-12-15

    A blood pre-centrifugation delay of 24 h at room temperature influenced the proton NMR spectroscopic profiles of human serum. A blood pre-centrifugation delay of 24 h at 4 Degree-Sign C did not influence the spectroscopic profile as compared with 4 h delays at either room temperature or 4 Degree-Sign C. Five or ten serum freeze-thaw cycles also influenced the proton NMR spectroscopic profiles. Certain common in vitro preanalytical variations occurring in biobanks may impact the metabolic profile of human serum.

  14. ELISA Cut-off Point for the Diagnosis of Human Brucellosis; a Comparison with Serum Agglutination Test

    Directory of Open Access Journals (Sweden)

    Anahita Sanaei Dashti

    2012-03-01

    Full Text Available Background: Brucellosis is a world-wide disease, which has a diverse clinical manifestation, and its diagnosis has to be proven by laboratory data. Serum agglutination test (SAT is the most-widely used test for diagnosing brucellosis. The enzyme linked immunosorbent assay (ELISA can also determine specific antibody classes against brucella. It is a sensitive, simple and rapid test, which could be an acceptable alternative to SAT with fewer limitations, however, like any other new test it should be further evaluated and standardized for various populations. This study was planned to determine an optimal cut-off point, for ELISA which would offer maximum sensitivity and specificity for the test when compared to SAT.Methods: Four hundred and seven patients with fever and other compatible symptoms of brucellosis were enrolled in the study. Serum agglutination test, 2-Mercaptoethanol test, and ELISA were performed on their sera. Results: The cut-off point of 53 IU/ml of ELISA-IgG yielded the maximal sensitivity and specificity comparing to the other levels of ELISA-IgG, and was considered the best cut off-point of ELISA-IgG to diagnose acute brucellosis. At this cut-off, the sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were 84.09%, 85.38%, 62.20, 94.90, 5.75, 0.18, respectively.Conclusion: The best cut-off point of ELISA-IgG is 53 IU/ml, which yields the maximal sensitivity and specificity to diagnose acute brucellosis.

  15. Anhydrobiosis and Freezing-Tolerance

    DEFF Research Database (Denmark)

    McGill, Lorraine; Shannon, Adam; Pisani, Davide

    2015-01-01

    Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode...... Panagrolaimus strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other Panagrolaimus isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth...

  16. Evaluation of Heat Flux Measurement as a New Process Analytical Technology Monitoring Tool in Freeze Drying.

    Science.gov (United States)

    Vollrath, Ilona; Pauli, Victoria; Friess, Wolfgang; Freitag, Angelika; Hawe, Andrea; Winter, Gerhard

    2017-05-01

    This study investigates the suitability of heat flux measurement as a new technique for monitoring product temperature and critical end points during freeze drying. The heat flux sensor is tightly mounted on the shelf and measures non-invasively (no contact with the product) the heat transferred from shelf to vial. Heat flux data were compared to comparative pressure measurement, thermocouple readings, and Karl Fischer titration as current state of the art monitoring techniques. The whole freeze drying process including freezing (both by ramp freezing and controlled nucleation) and primary and secondary drying was considered. We found that direct measurement of the transferred heat enables more insights into thermodynamics of the freezing process. Furthermore, a vial heat transfer coefficient can be calculated from heat flux data, which ultimately provides a non-invasive method to monitor product temperature throughout primary drying. The end point of primary drying determined by heat flux measurements was in accordance with the one defined by thermocouples. During secondary drying, heat flux measurements could not indicate the progress of drying as monitoring the residual moisture content. In conclusion, heat flux measurements are a promising new non-invasive tool for lyophilization process monitoring and development using energy transfer as a control parameter. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  17. Effects of high pressure freezing (HPF) on denaturation of natural actomyosin extracted from prawn (Metapenaeus ensis).

    Science.gov (United States)

    Cheng, Lina; Sun, Da-Wen; Zhu, Zhiwei; Zhang, Zhihang

    2017-08-15

    Effects of protein denaturation caused by high pressure freezing, involving Pressure-Factors (pressure, time) and Freezing-Factors (temperature, phase transition, recrystallization, ice crystal types), are complicated. In the current study, the conformation and functional changes of natural actomyosin (NAM) under pressure assisted freezing (PAF, 100,150,300,400,500MPa P -20°C/25min ), pressure shift freezing (PSF, 200MPa P -20°C/25min ), and immersion freezing ( 0.1MPa P -20°C/5min ) after pressure was released to 0.1MPa, as compared to normal immersion freezing process (IF, 0.1MPa P -20°C/30min ). Results indicated that PSF ( 200MPa P -20°C/30min ) could reduce the denaturation of frozen NAM and a pressure of 300MPa was the critical point to induce such a denaturation. During the periods of B→D in PSF or B→C→D in PAF, the generation and growth of ice crystals played an important role on changing the secondary and tertiary structure of the treated NAM. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The Critical Depth of Freeze-Thaw Soil under Different Types of Snow Cover

    Directory of Open Access Journals (Sweden)

    Qiang Fu

    2017-05-01

    Full Text Available Snow cover is the most common upper boundary condition influencing the soil freeze-thaw process in the black soil farming area of northern China. Snow is a porous dielectric cover, and its unique physical properties affect the soil moisture diffusion, heat conduction, freezing rate and other variables. To understand the spatial distribution of the soil water-heat and the variable characteristics of the critical depth of the soil water and heat, we used field data to analyze the freezing rate of soil and the extent of variation in soil water-heat in a unit soil layer under bare land (BL, natural snow (NS, compacted snow (CS and thick snow (TS treatments. The critical depth of the soil water and heat activity under different snow covers were determined based on the results of the analysis, and the variation fitting curve of the difference sequences on the soil temperature and water content between different soil layers and the surface 5-cm soil layer were used to verify the critical depth. The results were as follows: snow cover slowed the rate of soil freezing, and the soil freezing rate under the NS, CS and TS treatments decreased by 0.099 cm/day, 0.147 cm/day and 0.307 cm/day, respectively, compared with that under BL. In addition, the soil thawing time was delayed, and the effect was more significant with increased snow cover. During freeze-thaw cycles, the extent of variation in the water and heat time series in the shallow soil was relatively large, while there was less variation in the deep layer. There was a critical stratum in the vertical surface during hydrothermal migration, wherein the critical depth of soil water and heat change gradually increased with increasing snow cover. The variance in differences between the surface layer and both the soil water and heat in the different layers exhibited “steady-rising-steady” behavior, and the inflection point of the curve is the critical depth of soil freezing and thawing. This critical

  19. Freeze out in heavy ion reactions

    International Nuclear Information System (INIS)

    Csernai, Laszlo P.; Lazar, Zs.I.; Grassi, F.; Hama, Y.

    1998-01-01

    In fluid dynamical models the freeze out of particles across a three dimensional space-time hypersurface is discussed. The calculation of final momentum distribution of emitted particles is described for freeze out surfaces, with both space-like and time-like normals, taking into account conservation laws across the freeze out discontinuity. Generally the conservation laws lead to a change of temperature, baryon density and flow velocity at freeze out. (author)

  20. Monitoring Freeze Thaw Transitions in Arctic Soils using Complex Resistivity Method

    Science.gov (United States)

    Wu, Y.; Hubbard, S. S.; Ulrich, C.; Dafflon, B.; Wullschleger, S. D.

    2012-12-01

    The Arctic region, which is a sensitive system that has emerged as a focal point for climate change studies, is characterized by a large amount of stored carbon and a rapidly changing landscape. Seasonal freeze-thaw transitions in the Arctic alter subsurface biogeochemical processes that control greenhouse gas fluxes from the subsurface. Our ability to monitor freeze thaw cycles and associated biogeochemical transformations is critical to the development of process rich ecosystem models, which are in turn important for gaining a predictive understanding of Arctic terrestrial system evolution and feedbacks with climate. In this study, we conducted both laboratory and field investigations to explore the use of the complex resistivity method to monitor freeze thaw transitions of arctic soil in Barrow, AK. In the lab studies, freeze thaw transitions were induced on soil samples having different average carbon content through exposing the arctic soil to temperature controlled environments at +4 oC and -20 oC. Complex resistivity and temperature measurements were collected using electrical and temperature sensors installed along the soil columns. During the laboratory experiments, resistivity gradually changed over two orders of magnitude as the temperature was increased or decreased between -20 oC and 0 oC. Electrical phase responses at 1 Hz showed a dramatic and immediate response to the onset of freeze and thaw. Unlike the resistivity response, the phase response was found to be exclusively related to unfrozen water in the soil matrix, suggesting that this geophysical attribute can be used as a proxy for the monitoring of the onset and progression of the freeze-thaw transitions. Spectral electrical responses contained additional information about the controls of soil grain size distribution on the freeze thaw dynamics. Based on the demonstrated sensitivity of complex resistivity signals to the freeze thaw transitions, field complex resistivity data were collected over

  1. Freeze-dried microarterial allografts

    International Nuclear Information System (INIS)

    Raman, J.; Hargrave, J.C.

    1990-01-01

    Rehydrated freeze-dried microarterial allografts were implanted to bridge arterial defects using New Zealand White rabbits as the experimental model. Segments of artery from the rabbit ear and thigh were harvested and preserved for a minimum of 2 weeks after freeze-drying. These allografts, approximately 1 mm in diameter and ranging from 1.5 to 2.5 cm in length, were rehydrated and then implanted in low-pressure and high-pressure arterial systems. Poor patency was noted in low-pressure systems in both allografts and autografts, tested in 12 rabbits. In the high-pressure arterial systems, allografts that were freeze-dried and reconstituted failed in a group of 10 rabbits with an 8-week patency rate of 30 percent. Gamma irradiation in an effort to reduce infection and antigenicity of grafts after freeze-drying was associated with a patency rate of 10 percent at 8 weeks in this system in another group of 10 rabbits. Postoperative cyclosporin A therapy was associated with a patency rate of 22.2 percent in the high-pressure arterial system in a 9-rabbit group. Control autografts in this system in a group of 10 rabbits showed a 100 percent patency at 8 weeks. Microarterial grafts depend on perfusion pressure of the vascular bed for long-term patency. Rehydrated freeze-dried microarterial allografts do not seem to function well in lengths of 1 to 2.5 cm when implanted in a high-pressure arterial system. Freeze-dried arterial allografts are probably not antigenic

  2. Application of the Quality by Design Approach to the Freezing Step of Freeze-Drying: Building the Design Space.

    Science.gov (United States)

    Arsiccio, Andrea; Pisano, Roberto

    2018-06-01

    The present work shows a rational method for the development of the freezing step of a freeze-drying cycle. The current approach to the selection of freezing conditions is still empirical and nonsystematic, thus resulting in poor robustness of control strategy. The final aim of this work is to fill this gap, describing a rational procedure, based on mathematical modeling, for properly choosing the freezing conditions. Mechanistic models are used for the prediction of temperature profiles during freezing and dimension of ice crystals being formed. Mathematical description of the drying phase of freeze-drying is also coupled with the results obtained by freezing models, thus providing a comprehensive characterization of the lyophilization process. In this framework, deep understanding of the phenomena involved is required, and according to the Quality by Design approach, this knowledge can be used to build the design space. The step-by-step procedure for building the design space for freezing is thus described, and examples of applications are provided. The calculated design space is validated upon experimental data, and we show that it allows easy control of the freezing process and fast selection of appropriate operating conditions. Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  3. Validity of a portable urine refractometer: the effects of sample freezing.

    Science.gov (United States)

    Sparks, S Andy; Close, Graeme L

    2013-01-01

    The use of portable urine osmometers is widespread, but no studies have assessed the validity of this measurement technique. Furthermore, it is unclear what effect freezing has on osmolality. One-hundred participants of mean (±SD) age 25.1 ± 7.6 years, height 1.77 ± 0.1 m and weight 77.1 ± 10.8 kg provided single urine samples that were analysed using freeze point depression (FPD) and refractometry (RI). Samples were then frozen at -80°C (n = 81) and thawed prior to re-analysis. Differences between methods and freezing were determined using Wilcoxon's signed rank test. Relationships between measurements were assessed using intraclass correlation coefficients (ICC) and typical error of estimate (TE). Osmolality was lower (P = 0.001) using RI (634.2 ± 339.8 mOsm · kgH2O(-1)) compared with FPD (656.7 ± 334.1 mOsm · kgH2O(-1)) but the TE was trivial (0.17). Freezing significantly reduced mean osmolality using FPD (656.7 ± 341.1 to 606.5 ± 333.4 mOsm · kgH2O(-1); P < 0.001), but samples were still highly related following freezing (ICC, r = 0.979, P < 0.001, CI = 0.993-0.997; TE = 0.15; and r=0.995, P < 0.001, CI = 0.967-0.986; TE = 0.07 for RI and FPD respectively). Despite mean differences between methods and as a result of freezing, such differences are physiologically trivial. Therefore, the use of RI appears to be a valid measurement tool to determine urine osmolality.

  4. Cognitive Factors Affecting Freeze-like Behavior in Humans.

    Science.gov (United States)

    Alban, Michael W; Pocknell, Victoria

    2017-01-01

    Contemporary research on survival-related defensive behaviors has identified physiological markers of freeze/flight/fight. Our research focused on cognitive factors associated with freeze-like behavior in humans. Study 1 tested if an explicit decision to freeze is associated with the psychophysiological state of freezing. Heart rate deceleration occurred when participants chose to freeze. Study 2 varied the efficacy of freezing relative to other defense options and found "freeze" was responsive to variations in the perceived effectiveness of alternative actions. Study 3 tested if individual differences in motivational orientation affect preference for a "freeze" option when the efficacy of options is held constant. A trend in the predicted direction suggested that naturally occurring cognitions led loss-avoiders to select "freeze" more often than reward-seekers. In combination, our attention to the cognitive factors affecting freeze-like behavior in humans represents a preliminary step in addressing an important but neglected research area.

  5. The freezing of water bonded in the wheat (Triticum aestivum L.) grain studied by means protons magnetic relaxation method

    International Nuclear Information System (INIS)

    Haranczyk, H.; Jasinski, G.; Strzalka, K.

    1994-01-01

    Some biological aspects of water freezing in the wheat grain have been studied using NMR methods. Measuring of the relaxation times for freezing and liquid water shown absence of T 2 ∼100 μs and T 2 ∼1 ms separated components what pointed for some different way of water bonding

  6. Freeze-drying of HI-6-loaded recombinant human serum albumin nanoparticles for improved storage stability.

    Science.gov (United States)

    Dadparvar, Miriam; Wagner, Sylvia; Wien, Sascha; Worek, Franz; von Briesen, Hagen; Kreuter, Jörg

    2014-10-01

    Severe intoxications with organophosphates require the immediate administration of atropine in combination with acetyl cholinesterase (AChE) reactivators such as HI-6. Although this therapy regimen enables the treatment of peripheral symptoms, the blood-brain barrier (BBB) restricts the access of the hydrophilic antidotes to the central nervous system which could lead to a fatal respiratory arrest. Therefore, HI-6-loaded albumin nanoparticles were previously developed to enhance the transport across this barrier and were able to reactivate organophosphate-(OP)-inhibited AChE in an in vitro BBB model. Since HI-6 is known to be moisture-sensitive, the feasibility of freeze-drying of the HI-6-loaded nanoparticles was investigated in the present study using different cryo- and lyoprotectants at different concentrations. Trehalose and sucrose (3%, w/v)-containing formulations were superior to mannitol concerning the physicochemical parameters of the nanoparticles whereas trehalose-containing samples were subject of a prolonged storage stability study at temperatures between -20°C and +40°C for predetermined time intervals. Shelf-life computations of the freeze-dried HI-6 nanoparticle formulations revealed a shelf-life time of 18 months when stored at -20°C. The formulations' efficacy was proven in vitro by reactivation of OP-inhibited AChE after transport over a porcine brain capillary endothelial cell layer model. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. 9 CFR 590.536 - Freezing operations.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Freezing operations. 590.536 Section 590.536 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG..., and Facility Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean and...

  8. 9 CFR 590.534 - Freezing facilities.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Freezing facilities. 590.534 Section 590.534 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE EGG..., and Facility Requirements § 590.534 Freezing facilities. (a) Freezing rooms, either on or off the...

  9. 3 CFR - Pay Freeze

    Science.gov (United States)

    2010-01-01

    ... 3 The President 1 2010-01-01 2010-01-01 false Pay Freeze Presidential Documents Other Presidential Documents Memorandum of January 21, 2009 Pay Freeze Memorandum for the Assistant to the President and Chief... the White House staff forgo pay increases until further notice. Accordingly, as a signal of our shared...

  10. Interactions of human serum albumin with doxorubicin in different media

    Science.gov (United States)

    Gun'ko, Vladimir M.; Turov, Vladimir V.; Krupska, Tetyana V.; Tsapko, Magdalina D.

    2017-02-01

    Interactions of human serum albumin (10 wt% H2O and 0.3 wt% sodium caprylate) with doxorubicin hydrochloride (1 wt%) were studied alone or with addition of HCl (3.6 wt% HCl) using 1H NMR spectroscopy. A model of hydrated HSA/12DOX was calculated using PM7 method with COSMO showing large variations in the binding constant depending on structural features of DOX/HSA complexes. DOX molecules/ions displace bound water from narrow intramolecular voids in HSA that leads to diminution of freezing-melting point depression of strongly bound water (SBW). Structure of weakly bound water (WBW) depends much weaker on the presence of DOX than SBW because a major fraction of DOX is bound to adsorption sites of HSA. Addition of HCl results in strong changes in structure of macromolecules and organization of water in hydration shells of HSA (i.e., mainly SBW) and in the solution (i.e., WBW + non-bound bulk water).

  11. Practical limitations of ITS-90 from the mercury triple point to the silver freeze point

    International Nuclear Information System (INIS)

    Tavener, J. P.; Tavener, S. J.; Tavener, I. F.; Davies, N.

    2013-01-01

    The NPL published a forward to the ITS-90 text as follows:- 'The purpose of the ITS is to define procedures by which certain specified practical thermometers of the required quality can be calibrated in such a way that the values of temperature obtained from them can be precise and reproducible, while at the same time closely approximating the corresponding thermodynamic values.' [1]. The paper investigates the properties of thirty four lots of 6N pure metal used to make cells conforming to ITS-90 from mercury through silver over a period of twenty years. Three hundred individual cells are analysed by the impurities listed and supplied with each lot, melt and freeze curve slopes are also summarised for each lot and depressions calculated. These are then compared to the slopes and depressions suggested in the Supplementary Information for the ITS-90 and in CCT/2000-13 'Optimal Realizations'. Results are summarised, tabulated and discussed. Three lots of the thirty four were found to produce cells outside 6N expectations; however the remaining thirty one lots no matter how well or badly the accompanying certification was presented produced cells that conformed to 6N expectations as suggested in Supplementary Information to ITS-90 and CCT/2000-13

  12. Shaft Excavation in Frozen Ground at Point 5

    CERN Document Server

    Osborne, J

    2000-01-01

    Construction work on the 112 MCHF civil engineering contract started at Point 5 in August 1998. The new surface buildings and underground structures are necessary to accommodate the CMS detector for the LHC Project. The principal underground works consist of two new shafts, two parallel caverns separated by a supporting pillar, and a number of small connection tunnels and service galleries. The two shafts are to be sunk through approximately 50 m of water-bearing moraine to the underlying molasse rock. From a number of possible construction methods, ground freezing of the moraine was considered to be most appropriate. The ground freezing is used to control the groundwater and to support temporarily the moraine during excavation and lining of the shafts. The aim of this paper is to present the ground-freezing technique and to discuss the advantages and disadvantages of the system in the light of its first few months of running on the Point 5 site.

  13. Canalization of freeze tolerance in an alpine grasshopper.

    Science.gov (United States)

    Hawes, Timothy C

    2015-10-01

    In the Rock and Pillar Range, New Zealand, the alpine grasshopper, Sigaus australis Hutton, survives equilibrium freezing (EF) all-year round. A comparison of freeze tolerance (FT) in grasshoppers over four austral seasons for a 1 year period finds that: (a) the majority (>70%) of the sample population of grasshoppers survive single freeze-stress throughout the year; (b) exposure to increased freeze stress (multiple freeze-stress events) does not lead to a loss of freeze tolerance; and (c) responses to increased freeze stress reveal seasonal tuning of the FT adaptation to environmental temperatures. The Rock and Pillar sample population provides a clear example of the canalization of the FT adaptation. Seasonal variability in the extent of tolerance of multiple freezing events indicates that physiology is modulated to environmental temperatures by phenotypic plasticity - i.e. the FT adaptation is permanent and adjustable. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Pre-analytical sample quality: metabolite ratios as an intrinsic marker for prolonged room temperature exposure of serum samples.

    Directory of Open Access Journals (Sweden)

    Gabriele Anton

    Full Text Available Advances in the "omics" field bring about the need for a high number of good quality samples. Many omics studies take advantage of biobanked samples to meet this need. Most of the laboratory errors occur in the pre-analytical phase. Therefore evidence-based standard operating procedures for the pre-analytical phase as well as markers to distinguish between 'good' and 'bad' quality samples taking into account the desired downstream analysis are urgently needed. We studied concentration changes of metabolites in serum samples due to pre-storage handling conditions as well as due to repeated freeze-thaw cycles. We collected fasting serum samples and subjected aliquots to up to four freeze-thaw cycles and to pre-storage handling delays of 12, 24 and 36 hours at room temperature (RT and on wet and dry ice. For each treated aliquot, we quantified 127 metabolites through a targeted metabolomics approach. We found a clear signature of degradation in samples kept at RT. Storage on wet ice led to less pronounced concentration changes. 24 metabolites showed significant concentration changes at RT. In 22 of these, changes were already visible after only 12 hours of storage delay. Especially pronounced were increases in lysophosphatidylcholines and decreases in phosphatidylcholines. We showed that the ratio between the concentrations of these molecule classes could serve as a measure to distinguish between 'good' and 'bad' quality samples in our study. In contrast, we found quite stable metabolite concentrations during up to four freeze-thaw cycles. We concluded that pre-analytical RT handling of serum samples should be strictly avoided and serum samples should always be handled on wet ice or in cooling devices after centrifugation. Moreover, serum samples should be frozen at or below -80°C as soon as possible after centrifugation.

  15. Analytical validation of a new point-of-care assay for serum amyloid A in horses.

    Science.gov (United States)

    Schwartz, D; Pusterla, N; Jacobsen, S; Christopher, M M

    2018-01-17

    Serum amyloid A (SAA) is a major acute phase protein in horses. A new point-of-care (POC) test for SAA (Stablelab) is available, but studies evaluating its analytical accuracy are lacking. To evaluate the analytical performance of the SAA POC test by 1) determining linearity and precision, 2) comparing results in whole blood with those in serum or plasma, and 3) comparing POC results with those obtained using a previously validated turbidimetric immunoassay (TIA). Assay validation. Analytical validation of the POC test was done in accordance with American Society of Veterinary Clinical Pathology guidelines using residual equine serum/plasma and whole blood samples from the Clinical Pathology Laboratory at the University of California-Davis. A TIA was used as the reference method. We also evaluated the effect of haematocrit (HCT). The POC test was linear for SAA concentrations of up to at least 1000 μg/mL (r = 0.991). Intra-assay CVs were 13, 18 and 15% at high (782 μg/mL), intermediate (116 μg/mL) and low (64 μg/mL) concentrations. Inter-assay (inter-batch) CVs were 45, 14 and 15% at high (1372 μg/mL), intermediate (140 μg/mL) and low (56 μg/mL) concentrations. SAA results in whole blood were significantly lower than those in serum/plasma (P = 0.0002), but were positively correlated (r = 0.908) and not affected by HCT (P = 0.261); proportional negative bias was observed in samples with SAA>500 μg/mL. The difference between methods exceeded the 95% confidence interval of the combined imprecision of both methods (15%). Analytical validation could not be performed in whole blood, the sample most likely to be used stall side. The POC test has acceptable accuracy and precision in equine serum/plasma with SAA concentrations of up to at least 1000 μg/mL. Low inter-batch precision at high concentrations may affect serial measurements, and the use of the same test batch and sample type (serum/plasma or whole blood) is recommended. Comparison of results between the

  16. Gamma radiation effects on liofilized human serum

    International Nuclear Information System (INIS)

    Padron Soler, E.; Romay Penabad, Z.; Chavez Ardanza, A.; Hernandez Gonzalez, C.; Martin Gonzalez, O.; Garcia Gonzalez, I.; Prieto Miranda, E.

    1995-01-01

    Human freeze dried serum was artificially contaminated with Flavobacterium sp. for studying the effects of gamma radiation of it. The radiobiological parameters of the contaminator were determined and the sterilization dose was set. The quality of the product irradiated at both, calculated sterilization dose (8.5 kGy) an another one about 25 kGy was determined. It was made according to: sterility testing, total proteins, pH enzymes (alanina-aminotransferase, aspartato-aminotransferase, alkaline phosphatase), protein electrophoresis, fast performance liquid chromatographic and effect on the cellular growth. From the latter was concluded that the calculated sterilization dose was adequate form keeping the biological properties and viability of the irradiated serum. Nevertheless, the dose of 25 k Gy was not adequate because of its dangerous effects on the cell culture

  17. Effect of magnetic field on food freezing

    OpenAIRE

    村田, 圭治; 奥村, 太一; 荒賀, 浩一; 小堀, 康功

    2010-01-01

    [Abstract] This paper presents an experimental investigation on effects of magnetic field on food freezing process. Although purpose of food freezing is to suppress the deterioration of food, freezing breaks food tissue down, and some nutrient and delicious element flow out after thawing. Recently, a few of refrigeration equipments with electric and magnetic fields have attracted attention from food production companies and mass media. Water and tuna were freezed in magnetic field (100kH, 1.3...

  18. Investigation of the solubility and the potentials for purification of serum amyloid A (SAA) from equine acute phase serum

    DEFF Research Database (Denmark)

    Christensen, Michelle Brønniche; Sørensen, Jens Christian; Jacobsen, Stine

    2013-01-01

    BACKGROUND: Serum amyloid A (SAA) is useful as a diagnostic marker of systemic inflammation in horses, but only heterologous assays based on non-equine calibration and standardization are available for measurements of equine SAA. More accurate measurements could be obtained using purified species......-specific SAA in native conformation for assay calibration and standardization. Further knowledge about the biochemical properties of SAA would facilitate a future production of native species-specific calibration material Therefore, the aim of the study was an investigation of the solubility and potentials...... for purification of equine SAA based on biochemical properties.Freeze dried equine acute phase serum was dissolved in 70% 2-propanol, 8 M urea, and milli-Q water, respectively. Supercritical fluid extraction (SFE), size-exclusive chromatography (FPLC-SEC), and preparative isoelectric focusing (IEF) were performed...

  19. Correlation between glucose concentrations in serum, plasma, and whole blood measured by a point-of-care glucometer and serum glucose concentration measured by an automated biochemical analyzer for canine and feline blood samples.

    Science.gov (United States)

    Tauk, Barbara S; Drobatz, Kenneth J; Wallace, Koranda A; Hess, Rebecka S

    2015-06-15

    To investigate the correlation between glucose concentrations in serum, plasma, and whole blood measured by a point-of-care glucometer (POCG) and serum glucose concentration measured by a biochemical analyzer. Prospective clinical study. 96 blood samples from 80 dogs and 90 blood samples from 65 cats. Serum, plasma, and whole blood were obtained from each blood sample. The glucose concentrations in serum, plasma, and whole blood measured by a POCG were compared with the serum glucose concentration measured by a biochemical analyzer by use of the Lin concordance correlation coefficient (ρc) and Bland-Altman plots. For both canine and feline samples, glucose concentrations in serum and plasma measured by the POCG were more strongly correlated with the serum glucose concentration measured by the biochemical analyzer (ρc, 0.98 for both canine serum and plasma; ρc, 0.99 for both feline serum and plasma) than was that in whole blood (ρc, 0.62 for canine samples; ρc, 0.90 for feline samples). The mean difference between the glucose concentrations determined by the biochemical analyzer and the POCG in serum, plasma, and whole blood was 0.4, 0.3, and 31 mg/dL, respectively, for canine samples and 7, 6, and 32 mg/dL, respectively, for feline samples. Results indicated that use of a POCG to measure glucose concentrations in serum or plasma may increase the accuracy and reliability of diagnostic and treatment decisions associated with glucose homeostasis disorders in dogs and cats.

  20. Proton Pump Inhibitors and Serum Magnesium Levels in Patients With Torsades de Pointes

    Directory of Open Access Journals (Sweden)

    Pietro E. Lazzerini

    2018-04-01

    Full Text Available Background: Torsades de pointes (TdP is a life-threatening ventricular tachycardia occurring in long QT-syndrome patients. It usually develops when multiple QT-prolonging factors are concomitantly present, more frequently drugs and electrolyte imbalances. Since proton–pump inhibitors (PPIs-associated hypomagnesemia is an increasingly recognized adverse event, PPIs were recently included in the list of drugs with conditional risk of TdP, despite only few cases of TdP in PPI users have been reported so far.Objectives: Aim of the present study is to evaluate whether PPI-induced hypomagnesemia actually has a significant clinical impact on the risk of TdP in the general population.Methods: Forty-eight unselected patients who experienced TdP were consecutively enrolled (2008-2017. Shortly after the first TdP episode, in those patients who did not receive magnesium sulfate and/or potassium or calcium replacement therapy, serum electrolytes were measured and their relationship with PPI usage analyzed.Results: Many patients (28/48, 58% were under current PPI treatment when TdP occurred. Among TdP patients in whom serum electrolyte determinations were obtained before replacement therapy (27/48, those taking PPIs had significantly lower serum magnesium levels than those who did not. Hypomagnesemia occurred in ~40% of patients receiving PPIs (6/14, in all cases after an extended treatment (>2 weeks. In patients taking PPIs the mean QT-prolonging risk factor number was significantly higher than in those who did not, a difference which was mainly driven by lower magnesium levels.Conclusions: In unselected TdP patients, PPI-induced hypomagnesemia was common and significantly contributed to their cumulative arrhythmic risk. By providing clinical support to current recommendations, our data confirm that more awareness is needed when a PPI is prescribed, specifically as regards the risk of life-threatening arrhythmias.

  1. Freeze-thaw durability of air-entrained concrete.

    Science.gov (United States)

    Shang, Huai-Shuai; Yi, Ting-Hua

    2013-01-01

    One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles). The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss) and internal crack growth (characterized by the loss of dynamic modulus of elasticity). The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. The experimental study of C20, C25, C30, C40, and C50 air-entrained concrete specimens was completed according to "the test method of long-term and durability on ordinary concrete" GB/T 50082-2009. The dynamic modulus of elasticity and weight loss of specimens were measured after different cycles of freeze-thaw. The influence of freeze-thaw cycles on the relative dynamic modulus of elasticity and weight loss was analyzed. The findings showed that the dynamic modulus of elasticity and weight decreased as the freeze-thaw cycles were repeated. They revealed that the C30, C40, and C50 air-entrained concrete was still durable after 300 cycles of freeze-thaw according to the experimental results.

  2. Bulk water freezing dynamics on superhydrophobic surfaces

    Science.gov (United States)

    Chavan, S.; Carpenter, J.; Nallapaneni, M.; Chen, J. Y.; Miljkovic, N.

    2017-01-01

    In this study, we elucidate the mechanisms governing the heat-transfer mediated, non-thermodynamic limited, freezing delay on non-wetting surfaces for a variety of characteristic length scales, Lc (volume/surface area, 3 mm commercial superhydrophobic spray coatings, showing a monotonic increase in freezing time with coating thickness. The added thermal resistance of thicker coatings was much larger than that of the nanoscale superhydrophobic features, which reduced the droplet heat transfer and increased the total freezing time. Transient finite element method heat transfer simulations of the water slab freezing process were performed to calculate the overall heat transfer coefficient at the substrate-water/ice interface during freezing, and shown to be in the range of 1-2.5 kW/m2K for these experiments. The results shown here suggest that in order to exploit the heat-transfer mediated freezing delay, thicker superhydrophobic coatings must be deposited on the surface, where the coating resistance is comparable to the bulk water/ice conduction resistance.

  3. Determination of mercury in human serum and packed blood cells by neutron activation analysis

    International Nuclear Information System (INIS)

    Versieck, J.; Vanballenberghe, L.; Wittoek, A.; Vermeir, G.; Vandecasteele, C.

    1990-01-01

    A method is described for the determination of mercury in human blood serum and packed blood cells employing neutron activation analysis. Great attention was devoted to the collection and manipulation of the samples. The accuracy and precision of the method were tested by analyzing biological reference materials and by comparing the concentrations measured in a number of serum samples to those obtained by another, independent technique (cold vapor atomic absorption spectrometry) in the same samples. The article reports the levels measured in blood serum and packed blood cells samples from 15 adult volunteers, as well as the figures determined in a open-quotes second-generationclose quotes biological reference material (freeze-dried human serum), prepared and conditioned at the University of Ghent

  4. Applicable technical method for freeze-substitution of high pressure ...

    African Journals Online (AJOL)

    bmshsj

    2011-11-02

    Quintana, 1994) are available for the microscopic visualization of intracellular organelles. Cryo- fixation, plunge freezing, propane jet freezing, cold metal block freezing, and high pressure freezing provide advantages over chemical ...

  5. Mechanisms of deterioration of nutrients. [of freeze dried foods

    Science.gov (United States)

    Karel, M.; Flink, J. M.

    1976-01-01

    Methods which produce freeze dried foods of improved quality were examined with emphasis on storage stability. Specific topics discussed include: microstructure of freeze dried systems, investigation of structural changes in freeze dried systems, artificial food matrices, osmotic preconcentration to yield improved quality freeze dried fruits, and storage stability of osmotically preconcentrated freeze dried fruits.

  6. Freeze Protection in Gas Holders

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Duursma, Gail

    In cold weather, the water seals of gasholders need protection from freez- ing to avoid compromising the seal. These holders have a large reservoir of “tank water” at the base which is below ground. At present freeze- protection is achieved by external heating of the seal water which...

  7. Freeze dehydration of milk using microwave energy

    International Nuclear Information System (INIS)

    Souda, K.B.; Akyel, C.; Bilgen, E.

    1989-01-01

    This paper presents the results of experimental studies on heat and mass transfer during a microwave freeze dehydration process. An experimental system and procedure was developed to freeze dry milk. A 2500-W microwave system with an appropriate wave guide was set up and instrumented, and a procedure was experimentally developed to obtain milk powder first by freezing milk and then dehydrating it at low pressure using microwave energy. An unsteady-state analysis was used to derive a one-dimensional mathematical model of the freeze dehydration process in a microwave electromagnetic field

  8. Freeze-Thaw Durability of Air-Entrained Concrete

    Directory of Open Access Journals (Sweden)

    Huai-Shuai Shang

    2013-01-01

    Full Text Available One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles. The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss and internal crack growth (characterized by the loss of dynamic modulus of elasticity. The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. The experimental study of C20, C25, C30, C40, and C50 air-entrained concrete specimens was completed according to “the test method of long-term and durability on ordinary concrete” GB/T 50082-2009. The dynamic modulus of elasticity and weight loss of specimens were measured after different cycles of freeze-thaw. The influence of freeze-thaw cycles on the relative dynamic modulus of elasticity and weight loss was analyzed. The findings showed that the dynamic modulus of elasticity and weight decreased as the freeze-thaw cycles were repeated. They revealed that the C30, C40, and C50 air-entrained concrete was still durable after 300 cycles of freeze-thaw according to the experimental results.

  9. Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Ruixin [Institute of Medical Equipment, Academy of Military and Medical Sciences, No. 106, Wandong Street, Hedong District, Tianjin 300000 (China); Jiang, Wenxue, E-mail: jiangortholivea@sina.cn [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Sun, Yufu [Tianjin First Center Hospital, No. 24 Fukang Road, Tianjin, TJ 300192 (China); Li, Hui [Tianjin Medical University General Hospital, No. 154 Anshan Road, Tianjin, TJ 300052 (China)

    2016-09-02

    In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

  10. Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds

    International Nuclear Information System (INIS)

    Sun, Kai; Li, Ruixin; Jiang, Wenxue; Sun, Yufu; Li, Hui

    2016-01-01

    In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young’s modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. - Highlights: • Silk fibroin/collagen was fabricated using 3D printing. • Physical characterization and Cell compatibility were compared. • 3D printed scaffold exhibited better overall performance.

  11. Effect of chemical stabilizers on the thermostability and infectivity of a representative panel of freeze dried viruses.

    Directory of Open Access Journals (Sweden)

    Boris Pastorino

    Full Text Available As a partner of the European Virus Archive (EVA FP7 project, our laboratory maintains a large collection of freeze-dried viruses. The distribution of these viruses to academic researchers, public health organizations and industry is one major aim of the EVA consortium. It is known that lyophilization requires appropriate stabilizers to prevent inactivation of the virus. However, few studies have investigated the influence of different stabilizers and lyophilization protocols on the thermostability of different viruses. In order to identify optimal lyophilization conditions that will deliver maximum retention of viral infectivity titre, different stabilizer formulations containing trehalose, sorbitol, sucrose or foetal bovine serum were evaluated for their efficacy in stabilizing a representative panel of freeze dried viruses at different storage temperatures (-20°C, +4°C and +20°C for one week, the two latter mimicking suboptimal shipping conditions. The Tissue Culture Infectious Dose 50% (TCID50 assay was used to compare the titres of infectious virus. The results obtained using four relevant and model viruses (enveloped/non enveloped RNA/DNA viruses still serve to improve the freeze drying conditions needed for the development and the distribution of a large virus collection.

  12. A Theory of Immersion Freezing

    Science.gov (United States)

    Barahona, Donifan

    2017-01-01

    Immersion freezing is likely involved in the initiation of precipitation and determines to large extent the phase partitioning in convective clouds. Theoretical models commonly used to describe immersion freezing in atmospheric models are based on the classical nucleation theory which however neglects important interactions near the immersed particle that may affect nucleation rates. This work introduces a new theory of immersion freezing based on two premises. First, immersion ice nucleation is mediated by the modification of the properties of water near the particle-liquid interface, rather than by the geometry of the ice germ. Second, the same mechanism that leads to the decrease in the work of germ formation also decreases the mobility of water molecules near the immersed particle. These two premises allow establishing general thermodynamic constraints to the ice nucleation rate. Analysis of the new theory shows that active sites likely trigger ice nucleation, but they do not control the overall nucleation rate nor the probability of freezing. It also suggests that materials with different ice nucleation efficiency may exhibit similar freezing temperatures under similar conditions but differ in their sensitivity to particle surface area and cooling rate. Predicted nucleation rates show good agreement with observations for a diverse set of materials including dust, black carbon and bacterial ice nucleating particles. The application of the new theory within the NASA Global Earth System Model (GEOS-5) is also discussed.

  13. Vial freeze-drying, part 1: new insights into heat transfer characteristics of tubing and molded vials.

    Science.gov (United States)

    Hibler, Susanne; Wagner, Christophe; Gieseler, Henning

    2012-03-01

    In order to optimize a freeze-drying cycle, information regarding the heat transfer characteristics of the container system is imperative. Two most recently developed tubing (TopLyo™) and molded (EasyLyo™) vial designs were compared with a standard serum tubing and molded vial, a polymer vial (TopPac™), and an amber molded EasyLyo™. In addition, the impact of methodology on the determination of reliable vial heat transfer coefficient (K(v) ) data is examined in detail. All K(v) s were gravimetrically determined by sublimation tests with pure water at 50, 100, 200, and 400 mTorr. In contrast to the traditional assumption that molded vials exhibit inefficient heat transfer characteristics, these vials showed a very similar performance compared with their serum tubing counterparts in the relevant pressure range for freeze-drying. At 100 mTorr, the TopLyo™ center vials show only 4% higher K(v) values than the EasyLyo™ center vials. All glass vials outmatch the polymer vial in terms of heat transfer, up to 30% elevated heat transfer for the TopLyo™ center vials at 400 mTorr. Sublimation tests have demonstrated to be a valuable tool to investigate the heat transfer characteristics of vials, but results are dependent on methodology. New developments in molded vial manufacturing lead to improved heat transfer performance. Copyright © 2011 Wiley Periodicals, Inc.

  14. The discussion of nuclear power plant's cooling chain design for freezing site

    International Nuclear Information System (INIS)

    Hu Jian; Yang Ting; Jiang Xulun

    2014-01-01

    The Component cooling water system (RRI) and Essential service water system (SEC) are composed of Nuclear Power Plant's (NPP) cooling chain, which has its special requirement for freezing site from system design and safety point of view. The feature and difficulty of cooling chain design at freezing condition (when the intake water temperature is below O ℃) are represented. At present, several NPPs are in operation or under construction at freezing site in the world, including Pressurized Water Reactor (PWR) and Canadian Deuterium Uranium reactor (CANDU). By analyzing the thoughts and applicability of different kinds of cooling chain design at freezing site, one solution called 'SEC thermal discharge reflux' is proposed to remove the residual heat from Nuclear Island (NI) into heat sink safely in winter. The solution has been approved by National Nuclear Safety Administration (NNSA) in China and applied in one of CPR NPP in the north of China, which is able to solve several problems compared with the traditional solutions, such as 'Reactor low power operation', 'Reactor start-up for the first time', and 'Changeover of RRI/SEC trains in winter'. The solution is also able to prevent RRI/SEC heat exchanger from icing and avoid low flowrate in SEC pipes. Besides, considering of the economical efficiency, simple operation and control strategy is designed. (authors)

  15. Point-of-Admission Serum Electrolyte Profile of Children less than Five Years Old with Dehydration due to Acute Diarrhoea.

    Science.gov (United States)

    Okposio, Matthias Mariere; Onyiriuka, Alphonsus Ndidi; Abhulimhen-Iyoha, Blessing Imuetiyan

    2015-12-01

    Fluid, electrolytes and acid base disturbances are responsible for most deaths due to acute diarrhoea. The aim of this study is to describe the point-of-admission serum electrolyte profile of children with dehydration due to acute diarrhoea. In this cross-sectional study, the serum electrolyte levels of 185 children with dehydration due to acute diarrhoea were assessed at the point of admission at the Diarrhoea Treatment and Training Unit of the University of Benin Teaching Hospital. The age of the study population ranged from 29 days to 59 months. Out of a total of 185 subjects, 30 (16.2%), 114 (61.6%), and 41 (22.2%) had severe, moderate and mild dehydration, respectively. In addition, hyponatraemic dehydration was the most common type of dehydration, accounting for 60.5% of cases. Metabolic acidosis and hypokalaemia occurred in 59.5% and 44.3% of cases, respectively. Only the serum bicarbonate level was significantly affected by degree of dehydration (p = 0.001). Age of more than 12 months and presence of vomiting were significantly associated with hyponatraemia (p = 0.005 & p = 0.02), while age of less than or equal 12 months and absence of vomiting were associated with metabolic acidosis (p = 0.04 & p = 0.03). The degree of dehydration appears to be a good predictor of the occurrence of metabolic acidosis while age is a risk factor for hyponatraemia and metabolic acidosis.

  16. Freezing tolerance of conifer seeds and germinants.

    Science.gov (United States)

    Hawkins, B J; Guest, H J; Kolotelo, D

    2003-12-01

    Survival after freezing was measured for seeds and germinants of four seedlots each of interior spruce (Picea glauca x engelmannii complex), lodgepole pine (Pinus contorta Dougl. ex Loud.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western red cedar (Thuja plicata Donn ex D. Donn). Effects of eight seed treatments on post-freezing survival of seeds and germinants were tested: dry, imbibed and stratified seed, and seed placed in a growth chamber for 2, 5, 10, 15, 20 or 30 days in a 16-h photoperiod and a 22/17 degrees C thermoperiod. Survival was related to the water content of seeds and germinants, germination rate and seedlot origin. After freezing for 3 h at -196 degrees C, dry seed of most seedlots of interior spruce, Douglas-fir and western red cedar had 84-96% germination, whereas lodgepole pine seedlots had 53-82% germination. Freezing tolerance declined significantly after imbibition in lodgepole pine, Douglas-fir and interior spruce seed (western red cedar was not tested), and mean LT50 of imbibed seed of these species was -30, -24.5 and -20 degrees C, respectively. Freezing tolerance continued to decline to a minimum LT50 of -4 to -7 degrees C after 10 days in a growth chamber for interior spruce, Douglas-fir and lodgepole pine, or after 15 days for western red cedar. Minimum freezing tolerance was reached at the stage of rapid hypocotyl elongation. In all species, a slight increase in freezing tolerance of germinants was observed once cotyledons emerged from the seed coat. The decrease in freezing tolerance during the transition from dry to germinating seed correlated with increases in seed water content. Changes in freezing tolerance between 10 and 30 days in the growth chamber were not correlated with seedling water content. Within a species, seedlots differed significantly in freezing tolerance after 2 or 5 days in the growth chamber. Because all seedlots of interior spruce and lodgepole pine germinated quickly, there was no correlation

  17. Physical Stability of Freeze-Dried Isomalt Diastereomer Mixtures

    DEFF Research Database (Denmark)

    Koskinen, Anna-Kaisa; Fraser-Miller, Sara J.; Bøtker, Johan P.

    2016-01-01

    Purpose Isomalt is a sugar alcohol used as an excipient in commercially available solid oral dosage forms. The potential of isomalt as a novel freeze-drying excipient was studied in order to increase knowledge of the behavior of isomalt when it is freeze-dried. Methods Isomalt was freeze-dried in......Purpose Isomalt is a sugar alcohol used as an excipient in commercially available solid oral dosage forms. The potential of isomalt as a novel freeze-drying excipient was studied in order to increase knowledge of the behavior of isomalt when it is freeze-dried. Methods Isomalt was freeze......-dried in four different diastereomer compositions and its physical stability was investigated with differential scanning calorimetry, Fourier-transform infrared and Raman spectroscopy, X-ray powder diffraction, Karl-Fischer titration and thermogravimetric analysis in order to verify the solid state form...... of the diastereomer compositions showed signs of physical instability when stored in the highest relative humidity condition. The four different crystalline diastereomer mixtures showed specific identifiable solid state properties. Conclusions Isomalt was shown to be a suitable excipient for freeze-drying. Preferably...

  18. SELDI-TOF MS of quadruplicate urine and serum samples to evaluate changes related to storage conditions.

    Science.gov (United States)

    Traum, Avram Z; Wells, Meghan P; Aivado, Manuel; Libermann, Towia A; Ramoni, Marco F; Schachter, Asher D

    2006-03-01

    Proteomic profiling with SELDI-TOF MS has facilitated the discovery of disease-specific protein profiles. However, multicenter studies are often hindered by the logistics required for prompt deep-freezing of samples in liquid nitrogen or dry ice within the clinic setting prior to shipping. We report high concordance between MS profiles within sets of quadruplicate split urine and serum samples deep-frozen at 0, 2, 6, and 24 h after sample collection. Gage R&R results confirm that deep-freezing times are not a statistically significant source of SELDI-TOF MS variability for either blood or urine.

  19. Freezing the Master Production Schedule Under Rolling Planning Horizons

    OpenAIRE

    V. Sridharan; William L. Berry; V. Udayabhanu

    1987-01-01

    The stability of the Master Production Schedule (MPS) is a critical issue in managing production operations with a Material Requirements Planning System. One method of achieving stability is to freeze some portion or all of the MPS. While freezing the MPS can limit the number of schedule changes, it can also produce an increase in production and inventory costs. This paper examines three decision variables in freezing the MPS: the freezing method, the freeze interval length, and the planning ...

  20. The succinonitrile triple-point standard: a fixed point to improve the accuracy of temperature measurements in the clinical laboratory.

    Science.gov (United States)

    Mangum, B W

    1983-07-01

    In an investigation of the melting and freezing behavior of succinonitrile, the triple-point temperature was determined to be 58.0805 degrees C, with an estimated uncertainty of +/- 0.0015 degrees C relative to the International Practical Temperature Scale of 1968 (IPTS-68). The triple-point temperature of this material is evaluated as a temperature-fixed point, and some clinical laboratory applications of this fixed point are proposed. In conjunction with the gallium and ice points, the availability of succinonitrile permits thermistor thermometers to be calibrated accurately and easily on the IPTS-68.

  1. Report to the CCT on COOMET comparison COOMET.T-K3.1 (previously COOMET.T-S1): Key regional comparison of the national standards of temperature in the range from the triple point of water to the freezing point of zinc

    Science.gov (United States)

    Pokhodun, A. I.

    2010-01-01

    In the framework of the CIPM MRA, a first COOMET comparison "Comparison of the ITS-90 realizations in the range from 0.01 °C to 429.7485 °C (from the triple point of water to the freezing point of zinc)", registered in the KCDB under the identifier "COOMET.T-K3", was carried out in 2005-2007. Four national metrology institutes took part in this comparison: VNIIM (Russian Federation), SMU (Slovakia), BelGIM (Republic of Belarus) and NSC IM (Ukraine), and two of them (VNIIM and SMU) ensured the linkage with key comparisons CCT-K3 and CCT-K4, in order to disseminate the metrological equivalence to the measurement standards of NSC IM and BelGIM. NSC IM, however, had to withdraw its results, and at the meeting of Technical Committee T-10 of COOMET it was decided to carry out a supplementary bilateral comparison between VNIIM and the NSC IM for realization of the ITS-90 in the same range of temperature. This was registered in the KCDB under the identifier COOMET.T-S1 and measurements were performed in 2008-2009. From the results presented in this report, it is possible to draw the conclusion that the COOMET supplementary comparison COOMET.T-S1 demonstrates the CMC uncertainties claimed by the NSC IM for the melting point of gallium 0.236 mK (k = 2), and the freezing points of indium 1.040 mK (k = 2), tin 0.858 mK (k = 2) and zinc 0.944 mK (k = 2). In September 2012 the Working Group on key Comparisons (WG 7) of the CCT upgraded this comparison to a COOMET key comparison of the 'CCT-K3' type. It is now identified as COOMET.T-K3.1. In April 2013 this report was superseded by item 03006 in the Technical Supplement of 2013. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCT, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

  2. Human amniotic fluid stem cells (hAFSCs expressing p21 and cyclin D1 genes retain excellent viability after freezing with (dimethyl sulfoxide DMSO

    Directory of Open Access Journals (Sweden)

    Shiva Gholizadeh-Ghaleh Aziz

    2018-04-01

    Full Text Available Human amniotic fluid stem cells (hAFSCs have features intermediate between embryonic and adult SCs, can differentiate into lineages of all three germ layers, and do not develop into tumors in vivo. Moreover, hAFSCs can be easily obtained in routine procedures and there is no ethical or legal limitations regarding their use for clinical and experimental applications. The aim of this study was to assess the effect of slow freezing/thawing and two different concentrations of DMSO (10% DMSO + 90% fetal bovine serum [FBS] and 5% DMSO + 95% FBS on the survival of hAFSCs. hAFSCs were obtained from 5 pregnant women during amniocentesis at 16–22 weeks of gestation. The expression of pluripotency markers (Octamer-binding transcription factor 4 [Oct4] and NANOG by reverse transcription polymerase chain reaction and cell surface markers (cluster of differentiation [CD31], CD44, CD45, and CD90 by flow cytometry was analyzed before and after the slow-freezing. Cell viability was assessed by trypan blue exclusion or MTT assay. Quantitative mRNA expression of Oct4, NANOG, cyclin D1 and p21 was determined by real-time PCR before and after the slow-freezing. Pluripotency of hAFSCs was confirmed by NANOG and POU5F1 (Oct4 gene expression before and after slow-freezing. All hAFSC cultures were positive for CD44 and CD90. A higher viability of hAFSCs was observed after freezing with 90% FBS + 10% DMSO. There was increased expression of NANOG and decreased expression of POU5F1 gene after freezing, compared to control cells (before freezing. DMSO and the process of freezing did not significantly change the expression of p21 and cyclin D1 genes in hAFSCs. Overall, our results indicate the applicability of slow-freezing and DMSO in cryopreservation of SCs.

  3. Comparing contact and immersion freezing from continuous flow diffusion chambers

    Directory of Open Access Journals (Sweden)

    B. Nagare

    2016-07-01

    Full Text Available Ice nucleating particles (INPs in the atmosphere are responsible for glaciating cloud droplets between 237 and 273 K. Different mechanisms of heterogeneous ice nucleation can compete under mixed-phase cloud conditions. Contact freezing is considered relevant because higher ice nucleation temperatures than for immersion freezing for the same INPs were observed. It has limitations because its efficiency depends on the number of collisions between cloud droplets and INPs. To date, direct comparisons of contact and immersion freezing with the same INP, for similar residence times and concentrations, are lacking. This study compares immersion and contact freezing efficiencies of three different INPs. The contact freezing data were obtained with the ETH CoLlision Ice Nucleation CHamber (CLINCH using 80 µm diameter droplets, which can interact with INPs for residence times of 2 and 4 s in the chamber. The contact freezing efficiency was calculated by estimating the number of collisions between droplets and particles. Theoretical formulations of collision efficiencies gave too high freezing efficiencies for all investigated INPs, namely AgI particles with 200 nm electrical mobility diameter, 400 and 800 nm diameter Arizona Test Dust (ATD and kaolinite particles. Comparison of freezing efficiencies by contact and immersion freezing is therefore limited by the accuracy of collision efficiencies. The concentration of particles was 1000 cm−3 for ATD and kaolinite and 500, 1000, 2000 and 5000 cm−3 for AgI. For concentrations  <  5000 cm−3, the droplets collect only one particle on average during their time in the chamber. For ATD and kaolinite particles, contact freezing efficiencies at 2 s residence time were smaller than at 4 s, which is in disagreement with a collisional contact freezing process but in accordance with immersion freezing or adhesion freezing. With “adhesion freezing”, we refer to a contact nucleation

  4. Influence of the xanthan gum addition on the technological and sensory quality of baking products during the freezing storage

    Directory of Open Access Journals (Sweden)

    Tatiana Bojňanská

    2016-07-01

    Full Text Available The influence of the 0.16% xanthan gum addition in the recipe of the bread production and its influence on the baking and sensory quality of products was monitored during the process of our research. Prepared dough was inserted in the freezing box directly (-18°C and it was stored for one, two, three, four, five and six months. When the baking process was finished, the products with xanthan gum and the products without it were compared and evaluated by both objective and subjective methods. It was found that freezing, cooling and storage of the products without xanthan gum addition influenced the volume, vaulting and general appearance of the products in a negative way and loaves of bread were evaluated as unacceptable after four months of freezing. The quality of experimental loaves of bread with xanthan gum was, even after six months of freezing storage, comparable with freshly baked products. Despite the freezing, the volume of the products had an increased value. After first month of freezing the volume increased by 28.6% and after two months of freezing it increased by 23.8% both compared to the control. The vaulting in products processed by freezing was in the required optimal level during the whole period of freezing. Sensory evaluation results of loaves of bread with xanthan gum were the best after three, four and five months of storage in a freezer, when 98 points were achieved. During the monitored period of freezing, the addition of 0.16% of xanthan gum markedly contributed to the preservation of sensory and baking quality of the frozen wheat dough.

  5. Biophysical evaluation of aminoclay as an effective protectant for protein stabilization during freeze-drying and storage

    Directory of Open Access Journals (Sweden)

    Song JG

    2016-12-01

    Full Text Available Jae Geun Song, Sang Hoon Lee, Hyo-Kyung Han College of Pharmacy, Dongguk University, Goyang, South Korea Abstract: This study aimed to evaluate aminoclay (3-aminopropyl-functionalized magnesium phyllosilicate as an effective protectant for the stabilization of protein formulation in freeze-drying. Bovine serum albumin (BSA, as a model protein, was freeze-dried with aminoclay at various concentrations, and the effects of aminoclay on the structural stability of proteins were compared with those of the conventional stabilizers. The structural characteristics of the protein were determined by size exclusion chromatography (SEC, circular dichroism (CD, and Fourier transform infrared (FTIR spectroscopy. Furthermore, physicochemical and morphological characteristics were examined by X-ray powder diffraction (XRPD, differential scanning calorimetry (DSC, and scanning electron microscopy (SEM. XRPD and DSC patterns indicated that the glass transition temperature (Tg of the amorphous formulation of aminoclay mixed with proteins was gradually elevated as the concentration of aminoclay increased. FTIR and CD spectral analysis suggested that the protein structure was well maintained with aminoclay during the freeze-drying process and 3 months of storage at 4°C and 40°C. Furthermore, aminoclay conferred the greatest protection against aggregation and retained the monomer content of BSA even at a high temperature. The morphological characteristics of lyophilized proteins were also well conserved during the storage with aminoclay. These results suggested that aminoclay may be useful as an alternative stabilizer for maintaining the structural stability of protein formulations. Keywords: aminoclay, cryoprotectant, lyoprotectant, freeze-drying, protein, stability

  6. 7 CFR 58.620 - Freezing and packaging rooms.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Freezing and packaging rooms. 58.620 Section 58.620 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards....620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  7. Parameter Sensitivity of the Microdroplet Vacuum Freezing Process

    Directory of Open Access Journals (Sweden)

    Zhijun Zhang

    2015-01-01

    Full Text Available The vacuum freezing process of microdroplets (1 mm. Pressure and droplet diameter have an effect on cooling and freezing stages, but initial temperature only affects the cooling stage. The thermal conductivity coefficient kl affected the cooling stage, whereas ki affected the freezing stage. Heat capacity Cl affected the cooling stage, but Ci has virtually no effect on all stages. The actual latent heat of freezing ΔH was also affected. Higher density corresponds to lower cooling rate in the cooling stage.

  8. Isotope-dilution TurboFlow-LC-MS/MS method for simultaneous quantification of ten steroid metabolites in serum

    DEFF Research Database (Denmark)

    Søeborg, Tue; Frederiksen, Hanne; Johannsen, Trine Holm

    2017-01-01

    ), and estrone 3-sulfate (E1-S) in serum was developed and validated. Limits of quantification, variability (inter- and intra-day), analytical range and linearity were all found to be acceptable for clinical use. Furthermore, sample stability was evaluated including the influence of freeze-thaw cycles...

  9. Air-cooled steam condensers non-freeze warranties

    Energy Technology Data Exchange (ETDEWEB)

    Larinoff, M.W.

    1995-09-01

    What this paper is suggesting is the seller quote a condenser package with a LIMITED NON-FREEZE WARRANTY. Relieve the inexperienced buyer of the responsibility for selecting freeze protection design options. The seller cannot afford to over-design because of the added costs and the need for a competitive price. Yet he cannot under-design and allow the condenser tubes to freeze periodically and then pay the repair bills in accordance with the warranty.

  10. Influence of Rapid Freeze-Thaw Cycling on the Mechanical Properties of Sustainable Strain-Hardening Cement Composite (2SHCC

    Directory of Open Access Journals (Sweden)

    Seok-Joon Jang

    2014-02-01

    Full Text Available This paper provides experimental results to investigate the mechanical properties of sustainable strain-hardening cement composite (2SHCC for infrastructures after freeze-thaw actions. To improve the sustainability of SHCC materials in this study, high energy-consumptive components—silica sand, cement, and polyvinyl alcohol (PVA fibers—in the conventional SHCC materials are partially replaced with recycled materials such as recycled sand, fly ash, and polyethylene terephthalate (PET fibers, respectively. To investigate the mechanical properties of green SHCC that contains recycled materials, the cement, PVA fiber and silica sand were replaced with 10% fly ash, 25% PET fiber, and 10% recycled aggregate based on preliminary experimental results for the development of 2SHCC material, respectively. The dynamic modulus of elasticity and weight for 2SHCC material were measured at every 30 cycles of freeze-thaw. The effects of freeze-thaw cycles on the mechanical properties of sustainable SHCC are evaluated by conducting compressive tests, four-point flexural tests, direct tensile tests and prism splitting tests after 90, 180, and 300 cycles of rapid freeze-thaw. Freeze-thaw testing was conducted according to ASTM C 666 Procedure A. Test results show that after 300 cycles of freezing and thawing actions, the dynamic modulus of elasticity and mass loss of damaged 2SHCC were similar to those of virgin 2SHCC, while the freeze-thaw cycles influence mechanical properties of the 2SHCC material except for compressive behavior.

  11. Effects of Notch Introduction on 3-Point Bending Cutting Characteristics of Frozen Fish

    OpenAIRE

    Hagura, Yoshio; Suzuki, Kanichi

    2002-01-01

    We have proposed a freeze cutting method in which a three point bending load is applied on a frozen fish body to cut in round slices. Lowering the three-point bending load can facilitate the freeze cutting processing. Based on the idea that a notch in the fish body may lower the cutting load, the effect of introducing a notch was examined with respect to cutting stress and smoothness of cut surface in model fish meat and in saury. It was found that the introduced notch effectively lowered the...

  12. Study on dewatering of chemical sludge by freeze-thaw process

    International Nuclear Information System (INIS)

    Xu Shikun; Liu Pin

    1993-01-01

    The treatment of radioactive sludge that is produced from treating radioactive waste water contains radioactively is different from that of non-radioactive sludge. The methods of immersing freeze and simulated two-step freeze have been studied for the elementary properties of simulated low-level radioactive sledge, the effect of freezing temperature, freeze time, and settling time on volume-reduction factor. Some parameters for design of freeze-thaw device are provided

  13. Hot big bang or slow freeze?

    Science.gov (United States)

    Wetterich, C.

    2014-09-01

    We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze - a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple ;crossover model; without a big bang singularity. In the infinite past space-time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe.

  14. Recent developments in smart freezing technology applied to fresh foods.

    Science.gov (United States)

    Xu, Ji-Cheng; Zhang, Min; Mujumdar, Arun S; Adhikari, Benu

    2017-09-02

    Due to the increased awareness of consumers in sensorial and nutritional quality of frozen foods, the freezing technology has to seek new and innovative technologies for better retaining the fresh like quality of foods. In this article, we review the recent developments in smart freezing technology applied to fresh foods. The application of these intelligent technologies and the associated underpinning concepts have greatly improved the quality of frozen foods and the freezing efficiency. These technologies are able to automatically collect the information in-line during freezing and help control the freezing process better. Smart freezing technology includes new and intelligent technologies and concepts applied to the pretreatment of the frozen product, freezing processes, cold chain logistics as well as warehouse management. These technologies enable real-time monitoring of quality during the freezing process and help improve product quality and freezing efficiency. We also provide a brief overview of several sensing technologies used to achieve automatic control of individual steps of freezing process. These sensing technologies include computer vision, electronic nose, electronic tongue, digital simulation, confocal laser, near infrared spectroscopy, nuclear magnetic resonance technology and ultrasound. Understanding of the mechanism of these new technologies will be helpful for applying them to improve the quality of frozen foods.

  15. Freeze-all cycle for all normal responders?

    Science.gov (United States)

    Roque, Matheus; Valle, Marcello; Guimarães, Fernando; Sampaio, Marcos; Geber, Selmo

    2017-02-01

    The purpose of this study is to evaluate the freeze-all strategy in subgroups of normal responders, to assess whether this strategy is beneficial regardless of ovarian response, and to evaluate the possibility of implementing an individualized embryo transfer (iET) based on ovarian response. This was an observational, cohort study performed in a private IVF center. A total of 938 IVF cycles were included in this study. The patients were submitted to controlled ovarian stimulation (COS) with a gonadotropin-releasing hormone (GnRH) antagonist protocol and a cleavage-stage day 3 embryo transfer. We performed a comparison of outcomes between the fresh embryo transfer (n = 523) and the freeze-all cycles (n = 415). The analysis was performed in two subgroups of patients based on the number of retrieved oocytes: Group 1 (4-9 oocytes) and Group 2 (10-15 oocytes). In Group 1 (4-9 retrieved oocytes), the implantation rates (IR) were 17.9 and 20.5% (P = 0.259) in the fresh and freeze-all group, respectively; the ongoing pregnancy rates (OPR) were 31 and 33% (P = 0.577) in the fresh and freeze-all group, respectively. In Group 2 (10-15 oocytes), the IR were 22.1 and 30.1% (P = 0.028) and the OPR were 34 and 47% (P = 0.021) in the fresh and freeze-all groups, respectively. Although the freeze-all policy may be related to better in vitro fertilization (IVF) outcomes in normal responders, these potential advantages decrease with worsening ovarian response. Patients with poorer ovarian response do not benefit from the freeze-all strategy.

  16. Rational design of an influenza subunit vaccine powder with sugar glass technology : preventing conformational changes of haemagglutinin during freezing and freeze-drying

    NARCIS (Netherlands)

    Amorij, J-P; Meulenaar, J; Hinrichs, W L J; Stegmann, T; Huckriede, A; Coenen, F; Frijlink, H W

    2007-01-01

    The development of a stable influenza subunit vaccine in the dry state was investigated. The influence of various carbohydrates, buffer types and freezing rates on the integrity of haemagglutinin after freeze-thawing or freeze-drying was investigated with a range of analytical and immunological

  17. Freeze-dried, mucoadhesive system for vaginal delivery of the HIV microbicide, dapivirine: optimisation by an artificial neural network.

    Science.gov (United States)

    Woolfson, A David; Umrethia, Manish L; Kett, Victoria L; Malcolm, R Karl

    2010-03-30

    Dapivirine mucoadhesive gels and freeze-dried tablets were prepared using a 3x3x2 factorial design. An artificial neural network (ANN) with multi-layer perception was used to investigate the effect of hydroxypropyl-methylcellulose (HPMC): polyvinylpyrrolidone (PVP) ratio (X1), mucoadhesive concentration (X2) and delivery system (gel or freeze-dried mucoadhesive tablet, X3) on response variables; cumulative release of dapivirine at 24h (Q(24)), mucoadhesive force (F(max)) and zero-rate viscosity. Optimisation was performed by minimising the error between the experimental and predicted values of responses by ANN. The method was validated using check point analysis by preparing six formulations of gels and their corresponding freeze-dried tablets randomly selected from within the design space of contour plots. Experimental and predicted values of response variables were not significantly different (p>0.05, two-sided paired t-test). For gels, Q(24) values were higher than their corresponding freeze-dried tablets. F(max) values for freeze-dried tablets were significantly different (2-4 times greater, p>0.05, two-sided paired t-test) compared to equivalent gels. Freeze-dried tablets having lower values for X1 and higher values for X2 components offered the best compromise between effective dapivirine release, mucoadhesion and viscosity such that increased vaginal residence time was likely to be achieved. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  18. Medical and social egg freezing

    DEFF Research Database (Denmark)

    Lallemant, Camille; Vassard, Ditte; Andersen, Anders Nyboe

    2016-01-01

    INTRODUCTION: Until recently, limited options for preserving fertility in order to delay childbearing were available. Although egg freezing and successful thawing is now possible, it remains unclear to what extent women are aware of the availability of this technique, their attitudes towards its...... use, or the circumstances under which this technique may be considered. MATERIAL AND METHODS: An online cross-sectional survey was designed to investigate knowledge and attitudes of women in Denmark and the UK on egg freezing and their potential intentions regarding the procedure. RESULTS: Data...... was collected from September 2012 to September 2013 and the responses of 973 women were analyzed. In total, 83% of women reported having heard of egg freezing, and nearly all considered it acceptable for medical indications, whilst 89% considered it acceptable for social reasons. Overall, 19% expressed active...

  19. Response of seasonal soil freeze depth to climate change across China

    Science.gov (United States)

    Peng, Xiaoqing; Zhang, Tingjun; Frauenfeld, Oliver W.; Wang, Kang; Cao, Bin; Zhong, Xinyue; Su, Hang; Mu, Cuicui

    2017-05-01

    The response of seasonal soil freeze depth to climate change has repercussions for the surface energy and water balance, ecosystems, the carbon cycle, and soil nutrient exchange. Despite its importance, the response of soil freeze depth to climate change is largely unknown. This study employs the Stefan solution and observations from 845 meteorological stations to investigate the response of variations in soil freeze depth to climate change across China. Observations include daily air temperatures, daily soil temperatures at various depths, mean monthly gridded air temperatures, and the normalized difference vegetation index. Results show that soil freeze depth decreased significantly at a rate of -0.18 ± 0.03 cm yr-1, resulting in a net decrease of 8.05 ± 1.5 cm over 1967-2012 across China. On the regional scale, soil freeze depth decreases varied between 0.0 and 0.4 cm yr-1 in most parts of China during 1950-2009. By investigating potential climatic and environmental driving factors of soil freeze depth variability, we find that mean annual air temperature and ground surface temperature, air thawing index, ground surface thawing index, and vegetation growth are all negatively associated with soil freeze depth. Changes in snow depth are not correlated with soil freeze depth. Air and ground surface freezing indices are positively correlated with soil freeze depth. Comparing these potential driving factors of soil freeze depth, we find that freezing index and vegetation growth are more strongly correlated with soil freeze depth, while snow depth is not significant. We conclude that air temperature increases are responsible for the decrease in seasonal freeze depth. These results are important for understanding the soil freeze-thaw dynamics and the impacts of soil freeze depth on ecosystem and hydrological process.

  20. Energy efficiency of freezing tunnels: towards an optimal operation of compressors and air fans

    Energy Technology Data Exchange (ETDEWEB)

    Widell, Kristina Norne

    2012-07-01

    blade installed in the air flow at a critical location improved the air velocity distribution compared with no guide blade. Without the guide blade, the freezing times of the products were between 16 h and 32 h, but with a guide blade they were between 17h and 21 h, a span of only 4 h. These freezing times were calculated with a modified Planks equation. A numerical model was programmed in MATLAB and it was used to simulate the temperatures of the products. The model was a two-dimensional finite difference approximation of the heat conduction equation. The simulation results were compared to measured temperatures, to validate the model. The measured temperatures were also used for validation of another simulation program, programmed in Modelica. The final stage of this research involved testing different alternatives for reduced fan operation. The program for the product model was extended with models for calculating the energy consumption of the air fans and the compressors and using Airpak-simulated velocities. The air fan speed was reduced to 83%, 67%, 50% and 33% of full air fan speed. This was tested at 5 different points during the freezing period, to see how the freezing times were affected. Full air speed during the freezing period resulted in a total freezing time of 20 h. A reduction in air fan speed to 33% after 8 h resulted in an increase in total freezing time of 10 hours (47% longer) but reduced energy consumption to 73.8% of the baseline case. An alternative with only 4 h longer freezing time resulted in an energy consumption of 80.5% of the baseline case. It was assumed that the fans had variable speed drives. The effect of reduced air inlet temperature was also tested and the results show that this can reduce freezing times. The effect on the total energy consumption was not large and also depends on the rest of the refrigeration system. Issues raised by this thesis are relevant for future research. It is suggested that the main simulation program is

  1. Effect of freezing conditions on β-Tricalcium Phosphate /Camphene scaffold with micro sized particles fabricated by freeze casting.

    Science.gov (United States)

    Singh, Gurdev; Soundarapandian, S

    2018-03-01

    The long standing need of the implant manufacturing industries is to fabricate multi-matrix, customized porous scaffold as cost-effectively. In recent years, freeze casting has shown greater opportunity in the fabrication of porous scaffolds (tricalcium phosphate, hydroxyapatite, bioglass, alumina, etc.) such as at ease and good control over pore size, porosity, a range of materials and economic feasibility. In particular, tricalcium phosphate (TCP) has proved as it possesses good biocompatible (osteoinduction, osteoconduction, etc.) and biodegradability hence beta-tricalcium phosphate (β-TCP, particle size of 10µm) was used as base material and camphene was used as a freezing vehicle in this study. Both freezing conditions such as constant freezing temperature (CFT) and constant freezing rate (CFR) were used for six different conditional samples (CFT: 30, 35 and 40vol% solid loading; similarly CFR: 30, 35 and 40vol% solid loading) to study and understand the effect of various properties (pore size, porosity and compressive strength) of the freeze-cast porous scaffold. It was observed that the average size of the pore was varying linearly as from lower to higher when the solid loading was varying higher to lower. With the help of scanning electron micrographs (SEM), it was observed that the average size of pore during CFR (9.7/ 6.5/ 4.9µm) was comparatively higher than the process of CFT (6.0/ 4.8/ 2.6µm) with respect to the same solid loading (30/ 35/ 40vol%) conditions. From the Gas pycnometer analysis, it was found that the porosity in both freezing conditions (CFT, CFR) were almost near values such as 32.8% and 28.5%. Further to be observed that with the increase in solid loading, the total porosity value has decreased due to the reduction in the concentration of the freezing vehicle. Hence, the freezing vehicle was found as responsible for the formation of appropriate size and orientation of pores during freeze casting. The compressive strength (CS

  2. The choice of a suitable oligosaccharide to prevent aggregation of PEGylated nanoparticles during freeze thawing and freeze drying

    NARCIS (Netherlands)

    Hinrichs, Wouter; Manceñido, F A; Sanders, N N; Braeckmans, K; De Smedt, S C; Demeester, J; Frijlink, H W

    2006-01-01

    In a previous Study we have shown that the oligosaccharide inulin can prevent aggregation of poly(ethylene glycol) (PEG) coated plasmid DNA/cationic liposome complexes ('' PEGylated lipoplexes '') during freeze thawing and freeze drying [Hinrichs et al., 2005. J. Control. Release 103, 465]. By

  3. Faktor Influencing the Vacuum Freezing Rate of Liquid Food

    OpenAIRE

    Tambunan, Armansyah H

    2000-01-01

    Many,freezing methods, mechanicul as well as cryogenic, have been in wide application in food industries. Each method has its own advantage, but in regard with the food quality, freezing rule can be accomplished by the method is one of the tnost important factors. Nowadays, many researchers are conducting experiment in order to enhance thefi.eezing rate. This paper deals with the advantage of vacuum freezing method in enhancing the freezing rate and its applicability for liquidfood.Experinren...

  4. Increased spring freezing vulnerability for alpine shrubs under early snowmelt.

    Science.gov (United States)

    Wheeler, J A; Hoch, G; Cortés, A J; Sedlacek, J; Wipf, S; Rixen, C

    2014-05-01

    Alpine dwarf shrub communities are phenologically linked with snowmelt timing, so early spring exposure may increase risk of freezing damage during early development, and consequently reduce seasonal growth. We examined whether environmental factors (duration of snow cover, elevation) influenced size and the vulnerability of shrubs to spring freezing along elevational gradients and snow microhabitats by modelling the past frequency of spring freezing events. We sampled biomass and measured the size of Salix herbacea, Vaccinium myrtillus, Vaccinium uliginosum and Loiseleuria procumbens in late spring. Leaves were exposed to freezing temperatures to determine the temperature at which 50% of specimens are killed for each species and sampling site. By linking site snowmelt and temperatures to long-term climate measurements, we extrapolated the frequency of spring freezing events at each elevation, snow microhabitat and per species over 37 years. Snowmelt timing was significantly driven by microhabitat effects, but was independent of elevation. Shrub growth was neither enhanced nor reduced by earlier snowmelt, but decreased with elevation. Freezing resistance was strongly species dependent, and did not differ along the elevation or snowmelt gradient. Microclimate extrapolation suggested that potentially lethal freezing events (in May and June) occurred for three of the four species examined. Freezing events never occurred on late snow beds, and increased in frequency with earlier snowmelt and higher elevation. Extrapolated freezing events showed a slight, non-significant increase over the 37-year record. We suggest that earlier snowmelt does not enhance growth in four dominant alpine shrubs, but increases the risk of lethal spring freezing exposure for less freezing-resistant species.

  5. Hot big bang or slow freeze?

    Energy Technology Data Exchange (ETDEWEB)

    Wetterich, C.

    2014-09-07

    We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze — a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple “crossover model” without a big bang singularity. In the infinite past space–time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe.

  6. Hot big bang or slow freeze?

    International Nuclear Information System (INIS)

    Wetterich, C.

    2014-01-01

    We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze — a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple “crossover model” without a big bang singularity. In the infinite past space–time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe

  7. Hot big bang or slow freeze?

    Directory of Open Access Journals (Sweden)

    C. Wetterich

    2014-09-01

    Full Text Available We confront the big bang for the beginning of the universe with an equivalent picture of a slow freeze — a very cold and slowly evolving universe. In the freeze picture the masses of elementary particles increase and the gravitational constant decreases with cosmic time, while the Newtonian attraction remains unchanged. The freeze and big bang pictures both describe the same observations or physical reality. We present a simple “crossover model” without a big bang singularity. In the infinite past space–time is flat. Our model is compatible with present observations, describing the generation of primordial density fluctuations during inflation as well as the present transition to a dark energy-dominated universe.

  8. FREEZE DRYING PROCESS: A REVIEW

    OpenAIRE

    Soham Shukla

    2011-01-01

    Among the various methods of drying, this article has mentioned only one most important method, “Freeze drying”. This method is mainly used for the drying of thermo labile materials. This method works on the principle of sublimation. This method is divided into 3 steps for its better understanding; these are Freezing, Primary drying, and secondary drying. There are many advantages and disadvantages of this method, but still this is the most useful drying method nowadays.

  9. Successful long-term preservation of rat sperm by freeze-drying.

    Directory of Open Access Journals (Sweden)

    Takehito Kaneko

    Full Text Available BACKGROUND: Freeze-drying sperm has been developed as a new preservation method where liquid nitrogen is no longer necessary. An advantage of freeze-drying sperm is that it can be stored at 4 °C and transported at room temperature. Although the successful freeze-drying of sperm has been reported in a number of animals, the possibility of long-term preservation using this method has not yet been studied. METHODOLOGY/PRINCIPAL FINDINGS: Offspring were obtained from oocytes fertilized with rat epididymal sperm freeze-dried using a solution containing 10 mM Tris and 1 mM EDTA adjusted to pH 8.0. Tolerance of testicular sperm to freeze-drying was increased by pre-treatment with diamide. Offspring with normal fertility were obtained from oocytes fertilized with freeze-dried epididymal sperm stored at 4 °C for 5 years. CONCLUSIONS AND SIGNIFICANCE: Sperm with -SS- cross-linking in the thiol-disulfide of their protamine were highly tolerant to freeze-drying, and the fertility of freeze-dried sperm was maintained for 5 years without deterioration. This is the first report to demonstrate the successful freeze-drying of sperm using a new and simple method for long-term preservation.

  10. Increasing the aperture of x-ray mosaic lenses by freeze drying

    International Nuclear Information System (INIS)

    Koch, F; Marschall, F; Meiser, J; Márkus, O; Faisal, A; Schröter, T; Meyer, P; Kunka, D; Last, A; Mohr, J

    2015-01-01

    Point focus x-ray mosaic lenses are limited in aperture by the aspect ratio that can be reached in the micro fabrication process. In lithography based micro fabrication processes, which are used to fabricate the lens pillar structures, the achievable aspect ratio is restricted by structure collapse due to capillary forces which occur during drying after development. Capillary forces can be avoided by freeze drying, hence avoiding the direct phase change from liquid to gas. Substituting conventional drying by freeze drying using cyclohexane at a temperature of  −10 °C, we could increase the achievable aspect ratio for the triangular pillar structures with edge length of 10 to 45 µm of the x-ray mosaic lenses by up to a factor of 2.2 with no further changes in process, material or structural geometry. A maximum aspect ratio of 30 was achieved for pillars with 10 µm edge length. The process can readily be employed to other structures or lithography techniques. (paper)

  11. NIM Realization of the Gallium Triple Point

    Science.gov (United States)

    Xiaoke, Yan; Ping, Qiu; Yuning, Duan; Yongmei, Qu

    2003-09-01

    In the last three years (1999 to 2001), the gallium triple-point cell has been successfully developed, and much corresponding research has been carried out at the National Institute of Metrology (NIM), Beijing, China. This paper presents the cell design, apparatus and procedure for realizing the gallium triple point, and presents studies on the different freezing methods. The reproducibility is 0.03 mK, and the expanded uncertainty of realization of the gallium triple point is evaluated to be 0.17 mK (p=0.99, k=2.9). Also, the reproducibility of the gallium triple point was compared with that of the triple point of water.

  12. Optimization Of Freeze-Dried Starter For Yogurt By Full Factorial Experimental Design

    Directory of Open Access Journals (Sweden)

    Chen He

    2015-12-01

    Full Text Available With the rapidly development of fermented milk product, it is significant for enhancing the performance of starter culture. This paper not only investigated the influence of anti-freeze factors and freeze-drying protective agents on viable count, freeze-drying survival rate and yield of Lactobacillus bulgaricus (LB and Streptococcus thermophilus (ST, but also optimized the bacteria proportion of freeze-dried starter culture for yogurt by full factorial experimental design. The results showed as following: the freeze-drying protective agents or anti-freeze factors could enhanced survival rate of LB and ST; the freeze-dried LB and ST powders containing both of anti-freeze factors and freeze-drying protective agents had higher viable count and freeze-drying survival rate that were 84.7% and 79.7% respectively; In terms of fermentation performance, the best group of freeze-dried starter for yogurt was the compound of LB3 and ST2.

  13. A rapidly negotiable first-stage nuclear freeze

    International Nuclear Information System (INIS)

    Anon.

    1988-01-01

    This paper reports on the objective of a nuclear freeze which is to slow down or stop the so-far inexorable development and deployment of more and more (read destructive and deadly) nuclear warheads. The essential notion is not new. The proposed treaty for a comprehensive ban on nuclear tests that was very nearly negotiated in 1959 was perhaps the first serious effort to obtain a nuclear freeze, albeit a partial one. Growing concern about the nuclear arms race has led to greatly increased interest in much broader and more effective freezes. A comprehensive nuclear freeze, one that would stop all stages in the manufacture, testing, and deployment of nuclear warheads, would clearly be very desirable and have a great impact. It would not, however, deal with the other worrisome aspects of nuclear weapons, which is the very large number of such weapons that already exist

  14. Mechanisms of deterioration of nutrients. [improved quality of freeze-dried foods

    Science.gov (United States)

    Karel, M.; Flink, J. M.

    1978-01-01

    Methods for improving the quality of freeze-dried foods were investigated. Areas discussed include: (1) microstructure of freeze-dried systems, (2) structural changes in freeze-dried systems, (3) artificial food matrices, and (4) osmotic preconcentration to yield improved freeze-dried products.

  15. Cost-Effectiveness of the Freeze-All Policy.

    Science.gov (United States)

    Roque, Matheus; Valle, Marcello; Guimarães, Fernando; Sampaio, Marcos; Geber, Selmo

    2015-08-01

    To evaluate the cost-effectiveness of freeze-all cycles when compared to fresh embryo transfer. This was an observational study with a cost-effectiveness analysis. The analysis consisted of 530 intracytoplasmic sperm injection (ICSI) cycles in a private center in Brazil between January 2012 and December 2013. A total of 530 intracytoplasmic sperm injection (ICSI) cycles - 351 fresh embryo transfers and 179 freeze-all cycles - with a gonadotropin-releasing hormone (GnRH) antagonist protocol and day 3 embryo transfers. The pregnancy rate was 31.1% in the fresh group and 39.7% in the freeze-all group. We performed two scenario analyses for costs. In scenario 1, we included those costs associated with the ICSI cycle (monitoring during controlled ovarian stimulation [COS], oocyte retrieval, embryo transfer, IVF laboratory, and medical costs), embryo cryopreservation of supernumerary embryos, hormone measurements during COS and endometrial priming, medication use (during COS, endometrial priming, and luteal phase support), ultrasound scan for frozen- thawed embryo transfer (FET), obstetric ultrasounds, and miscarriage. The total cost (in USD) per pregnancy was statistically lower in the freeze-all cycles (19,156.73 ± 1,732.99) when compared to the fresh cycles (23,059.72 ± 2,347.02). Even in Scenario 2, when charging all of the patients in the freeze-all group for cryopreservation (regardless of supernumerary embryos) and for FET, the fresh cycles had a statistically significant increase in treatment costs per ongoing pregnancy. The results presented in this study suggest that the freeze-all policy is a cost-effective strategy when compared to fresh embryo transfer.

  16. P-wave velocity changes in freezing hard low-porosity rocks: a laboratory-based time-average model

    Directory of Open Access Journals (Sweden)

    D. Draebing

    2012-10-01

    Full Text Available P-wave refraction seismics is a key method in permafrost research but its applicability to low-porosity rocks, which constitute alpine rock walls, has been denied in prior studies. These studies explain p-wave velocity changes in freezing rocks exclusively due to changing velocities of pore infill, i.e. water, air and ice. In existing models, no significant velocity increase is expected for low-porosity bedrock. We postulate, that mixing laws apply for high-porosity rocks, but freezing in confined space in low-porosity bedrock also alters physical rock matrix properties. In the laboratory, we measured p-wave velocities of 22 decimetre-large low-porosity (< 10% metamorphic, magmatic and sedimentary rock samples from permafrost sites with a natural texture (> 100 micro-fissures from 25 °C to −15 °C in 0.3 °C increments close to the freezing point. When freezing, p-wave velocity increases by 11–166% perpendicular to cleavage/bedding and equivalent to a matrix velocity increase from 11–200% coincident to an anisotropy decrease in most samples. The expansion of rigid bedrock upon freezing is restricted and ice pressure will increase matrix velocity and decrease anisotropy while changing velocities of the pore infill are insignificant. Here, we present a modified Timur's two-phase-equation implementing changes in matrix velocity dependent on lithology and demonstrate the general applicability of refraction seismics to differentiate frozen and unfrozen low-porosity bedrock.

  17. Metabolic changes in Avena sativa crowns recovering from freezing.

    Directory of Open Access Journals (Sweden)

    Cynthia A Henson

    Full Text Available Extensive research has been conducted on cold acclimation and freezing tolerance of fall-sown cereal plants due to their economic importance; however, little has been reported on the biochemical changes occurring over time after the freezing conditions are replaced by conditions favorable for recovery and growth such as would occur during spring. In this study, GC-MS was used to detect metabolic changes in the overwintering crown tissue of oat (Avena sativa L. during a fourteen day time-course after freezing. Metabolomic analysis revealed increases in most amino acids, particularly proline, 5-oxoproline and arginine, which increased greatly in crowns that were frozen compared to controls and correlated very significantly with days after freezing. In contrast, sugar and sugar related metabolites were little changed by freezing, except sucrose and fructose which decreased dramatically. In frozen tissue all TCA cycle metabolites, especially citrate and malate, decreased in relation to unfrozen tissue. Alterations in some amino acid pools after freezing were similar to those observed in cold acclimation whereas most changes in sugar pools after freezing were not. These similarities and differences suggest that there are common as well as unique genetic mechanisms between these two environmental conditions that are crucial to the winter survival of plants.

  18. Applications of Simulator Freeze to Carrier Glideslope Tracking Instruction.

    Science.gov (United States)

    1982-07-01

    Showing Datum Bars and Meatball . .. .. .. ... .. ... .... 19 4 Freezes Per Trial Averaged Across Freeze Conditions and Across 4-Trial Blocks of Training...algorithm linearly increased the criterion in meatball units from 1.0 at 6000 feet from the ramp to 1.5 at the ramp. "Freezes" did not occur beyond 6000

  19. Effects of sugar alcohol and proteins on the survival of Lactobacillus bulgaricus LB6 during freeze drying.

    Science.gov (United States)

    Chen, He; Chen, Shiwei; Chen, Hongli; Wu, Yanyan; Shu, Guowei

    2015-01-01

    Lactobacillus bulgaricus LB6 is a bacterium which was selected in the commercial yoghurt with high angiotensin converting enzyme (ACE) inhibitory activity. Preparation of concentrated starter cultures via freeze drying is of practical importance to dairy and food industries. We optimized the optimal sugar alcohol and proteins for Lactobacillus bulgaricus LB6 during the process of freeze drying using a Plackett-Burman design. In our initial tests survival rate and the number of viable cells were associated with the type of lyoprotectant used and so our optimization protocol focused on increasing survival rate. Substances that had previously had a protective effect during freeze drying were investigated, for example: mannitol, sorbitol, xylitol, meso-erythritol, lactitol, whey protein isolate 90, bovine serum albumin, and whey protein concentrate 80 and soy protein isolate 70. We found that the optimum sugar alcohol and proteins for survival of Lactobacillus bulgaricus LB6 were whey protein concentrate (p = 0.0040 for survival rate), xylitol (p = 0.0067 for survival rate) and sorbitol (p = 0.0073 for survival rate), they showed positive effect (whey protein concentrate and sorbitol) or negative effect (xylitol). The effectiveness of three chosen sugar alcohols and protein implied that they could be used as lyoprotectant for Lactobacillus bulgaricus LB6 in the further research, the optimal composition of sugar alcohol and protein for the lyoprotectant use must be established.

  20. A water activity based model of heterogeneous ice nucleation kinetics for freezing of water and aqueous solution droplets.

    Science.gov (United States)

    Knopf, Daniel A; Alpert, Peter A

    2013-01-01

    Immersion freezing of water and aqueous solutions by particles acting as ice nuclei (IN) is a common process of heterogeneous ice nucleation which occurs in many environments, especially in the atmosphere where it results in the glaciation of clouds. Here we experimentally show, using a variety of IN types suspended in various aqueous solutions, that immersion freezing temperatures and kinetics can be described solely by temperature, T, and solution water activity, a(w), which is the ratio of the vapour pressure of the solution and the saturation water vapour pressure under the same conditions and, in equilibrium, equivalent to relative humidity (RH). This allows the freezing point and corresponding heterogeneous ice nucleation rate coefficient, J(het), to be uniquely expressed by T and a(w), a result we term the a(w) based immersion freezing model (ABIFM). This method is independent of the nature of the solute and accounts for several varying parameters, including cooling rate and IN surface area, while providing a holistic description of immersion freezing and allowing prediction of freezing temperatures, J(het), frozen fractions, ice particle production rates and numbers. Our findings are based on experimental freezing data collected for various IN surface areas, A, and cooling rates, r, of droplets variously containing marine biogenic material, two soil humic acids, four mineral dusts, and one organic monolayer acting as IN. For all investigated IN types we demonstrate that droplet freezing temperatures increase as A increases. Similarly, droplet freezing temperatures increase as the cooling rate decreases. The log10(J(het)) values for the various IN types derived exclusively by Tand a(w), provide a complete description of the heterogeneous ice nucleation kinetics. Thus, the ABIFM can be applied over the entire range of T, RH, total particulate surface area, and cloud activation timescales typical of atmospheric conditions. Lastly, we demonstrate that ABIFM can

  1. The stability of complement-mediated bactericidal activity in human serum against Salmonella.

    Directory of Open Access Journals (Sweden)

    Colette M O'Shaughnessy

    Full Text Available The complement cascade includes heat-labile proteins and care is required when handling serum in order to preserve its functional integrity. We have previously used a whole human serum bactericidal assay to show that antibody and an intact complement system are required in blood for killing of invasive isolates of Salmonella. The aim of the present study was to evaluate the conditions under which human serum can be stored and manipulated while maintaining complement integrity. Serum bactericidal activity against Salmonella was maintained for a minimum of 35 days when stored at 4°C, eight days at 22°C and 54 hours at 37°C. Up to three freeze-thaw cycles had no effect on the persistence of bactericidal activity and hemolytic complement assays confirmed no effect on complement function. Delay in the separation of serum for up to four days from clotted blood stored at 22°C did not affect bactericidal activity. Dilution of serum resulted in an increased rate of loss of bactericidal activity and so serum should be stored undiluted. These findings indicate that the current guidelines concerning manipulation and storage of human serum to preserve complement integrity and function leave a large margin for safety with regards to bactericidal activity against Salmonella. The study provides a scheme for determining the requirements for serum handling in relation to functional activity of complement in other systems.

  2. Freeze block testing of buried waste lines

    International Nuclear Information System (INIS)

    Robbins, E.D.; Willi, J.C.

    1976-01-01

    An investigation was conducted to demonstrate application of freeze blocking in waste transfer lines such that a hydrostatic pressure test can be applied. A shop test was conducted on a 20-foot length, 3-inch schedule 40, carbon steel pipe using a coolant of dry ice and Freon. The positive results from these tests prompted a similar employment of the freeze block method in hydrostatic pressure testing the feed inlet leading to 241-S-101 Waste Tank. This pipeline is a 3-inch schedule 10, stainless steel pipe approximately 800 feet long. The freeze block was formed near the lower end of the pipe as it entered the 101-S Waste Tank and a pressure hold test was applied to this pipeline. This test proved the integrity of the pipeline in question, and demonstrated the validity of freeze blocking an open-ended pipeline which could not be hydrotested in other conventional ways. The field demonstration facility, costing $30,200 was completed late in 1975

  3. Origin of melting point depression for rare gas solids confined in carbon pores

    International Nuclear Information System (INIS)

    Morishige, Kunimitsu; Kataoka, Takaaki

    2015-01-01

    To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ∼0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point

  4. Origin of melting point depression for rare gas solids confined in carbon pores

    Energy Technology Data Exchange (ETDEWEB)

    Morishige, Kunimitsu, E-mail: morishi@chem.ous.ac.jp; Kataoka, Takaaki [Department of Chemistry, Okayama University of Science, 1-1 Ridai-cho, Kita-ku, Okayama 700-0005 (Japan)

    2015-07-21

    To obtain insights into the mechanism of the melting-point depression of rare gas solids confined in crystalline carbon pores, we examined the freezing and melting behavior of Xe and Ar confined to the crystalline pores of ordered mesoporous carbons as well as compressed exfoliated graphite compared to the amorphous pores of ordered mesoporous silicas, by means of X-ray diffraction. For the Xe and Ar confined to the crystalline carbon pores, there was no appreciable thermal hysteresis between freezing and melting. Furthermore, the position of the main diffraction peak did not change appreciably on freezing and melting. This strongly suggests that the liquids confined in the carbon pores form a multilayered structure parallel to the smooth walls. For the Xe and Ar confined to the amorphous silica pores, on the other hand, the position of the main diffraction peak shifted into higher scattering angle on freezing suggested that the density of the confined solid is distinctly larger than for the confined liquid. Using compressed exfoliated graphite with carbon walls of higher crystallinity, we observed that three-dimensional (3D) microcrystals of Xe confined in the slit-shaped pores melted to leave the unmelted bilayers on the pore walls below the bulk triple point. The lattice spacing of the 3D microcrystals confined is larger by ∼0.7% than that of the bilayer next to the pore walls in the vicinity of the melting point.

  5. Predictive modeling of freezing and thawing of frost-susceptible soils.

    Science.gov (United States)

    2015-09-01

    Frost depth is an essential factor in design of various transportation infrastructures. In frost : susceptible soils, as soils freezes, water migrates through the soil voids below the freezing line : towards the freezing front and causes excessive he...

  6. Dissipative corrections to particle spectra and anisotropic flow from a saddle-point approximation to kinetic freeze out

    International Nuclear Information System (INIS)

    Lang, Christian; Borghini, Nicolas

    2014-01-01

    A significant fraction of the changes in momentum distributions induced by dissipative phenomena in the description of the fluid fireball created in ultrarelativistic heavy-ion collisions actually take place when the fluid turns into individual particles. We study these corrections in the limit of a low freeze-out temperature of the flowing medium, and we show that they mostly affect particles with a higher velocity than the fluid. For these, we derive relations between different flow harmonics, from which the functional form of the dissipative corrections could ultimately be reconstructed from experimental data. (orig.)

  7. Multiple Glass Transitions and Freezing Events of Aqueous Citric Acid

    Science.gov (United States)

    2014-01-01

    Calorimetric and optical cryo-microscope measurements of 10–64 wt % citric acid (CA) solutions subjected to moderate (3 K/min) and slow (0.5 and 0.1 K/min) cooling/warming rates and also to quenching/moderate warming between 320 and 133 K are presented. Depending on solution concentration and cooling rate, the obtained thermograms show one freezing event and from one to three liquid–glass transitions upon cooling and from one to six liquid–glass and reverse glass–liquid transitions, one or two freezing events, and one melting event upon warming of frozen/glassy CA/H2O. The multiple freezing events and glass transitions pertain to the mother CA/H2O solution itself and two freeze-concentrated solution regions, FCS1 and FCS2, of different concentrations. The FCS1 and FCS2 (or FCS22) are formed during the freezing of CA/H2O upon cooling and/or during the freezing upon warming of partly glassy or entirely glassy mother CA/H2O. The formation of two FCS1 and FCS22 regions during the freezing upon warming to our best knowledge has never been reported before. Using an optical cryo-microscope, we are able to observe the formation of a continuous ice framework (IF) and its morphology and reciprocal distribution of IF/(FCS1 + FCS2). Our results provide a new look at the freezing and glass transition behavior of aqueous solutions and can be used for the optimization of lyophilization and freezing of foods and biopharmaceutical formulations, among many other applications where freezing plays a crucial role. PMID:25482069

  8. Application of freeze-drying technology in manufacturing orally disintegrating films.

    Science.gov (United States)

    Liew, Kai Bin; Odeniyi, Michael Ayodele; Peh, Kok-Khiang

    2016-01-01

    Freeze drying technology has not been maximized and reported in manufacturing orally disintegrating films. The aim of this study was to explore the freeze drying technology in the formulation of sildenafil orally disintegrating films and compare the physical properties with heat-dried orally disintegrating film. Central composite design was used to investigate the effects of three factors, namely concentration of carbopol, wheat starch and polyethylene glycol 400 on the tensile strength and disintegration time of the film. Heat-dried films had higher tensile strength than films prepared using freeze-dried method. For folding endurance, freeze-dried films showed improved endurance than heat-dried films. Moreover, films prepared using freeze-dried methods were thicker and had faster disintegration time. Formulations with higher amount of carbopol and starch showed higher tensile strength and thickness whereas formulations with higher PEG 400 content showed better flexibility. Scanning electron microscopy showed that the freeze-dried films had more porous structure compared to the heat-dried film as a result of the release of water molecule from the frozen structure when it was subjected to freeze drying process. The sildenafil film was palatable. The dissolution profiles of freeze-dried and heat-dried films were similar to Viagra® with f2 of 51.04 and 65.98, respectively.

  9. Three-Dimensional Microstructure of Biological Tissues during Freezing and Thawing

    Science.gov (United States)

    Ishiguro, Hiroshi; Horimizu, Takashi; Kataori, Akinobu; Kajigaya, Hiroshi

    Three-dimensional behavior of ice crystals and cells during the freezing and thawing of biological tissues was investigated microscopically in real time by using a confocal laser scanning microscope(CLSM) and a fluorescent dye, acridine orange (AO). Fresh tender meat (2nd pectoral muscles) of chicken was stained with the AO in physiological saline to distinguish ice crystals and cells by their different colors, and then frozen and thawed under two different thermal protocols: a) slow-cooling and rapid-warming and b) rapid-cooling and rapid-warming. The CLSM noninvasively produced optical tomograms of the tissues to clarify the pattern of freezing, morphology of ice crystals in the tissues, and the interaction between ice crystals and cells. Also, the tissues were morphologically investigated by pathological means after the freezing and thawing. Typical freezing pattern during the slow-cooling was extracellular-freezing, and those during the rapid-cooling were extracellular-freezing and intracellular freezing with a lot of fine ice crystals in the cells. Cracks caused by the extracellular and intracellular ice crystals remained in the muscle tissues after the thawing. The results obtained by using the CLSM/dye method were consistent with pathologically morphological changes in the tissues through freezing and thawing.

  10. [Effect of freezing and cooking on the texture and electrophoretic pattern of the proteins of octopus arms (Octopus vulgaris)].

    Science.gov (United States)

    Reyes, Genara; Nirchio, Mauro; Bello, Rafael; Borderías, Javier

    2014-09-01

    Texture is the most valuable feature in cephalopods. Factors that mainly affect the texture of octopus are: freezing, scalding and cooking. The aim of this study was to assess the effect of freezing, scalding and length of cooking time on the texture and electrophoretic pattern of proteins of octopus arms. Octopuses were trapped near Margarita Island and carried with ice to the laboratory where they were packed and subjected to: a) freezing at -27 degrees C or at -20 degrees C b) scalding c) cooking for 25 min, 35 min or 45 min. Shear force was determined by Kramer cell on strips of octopus arms. SDS-PAGE was done according to the Laemmli method with 12% polyacrilamide gels. A sensory evaluation of the preference of texture was carried out using a hedonic scale of 7-points and a non-trained panel. Octopus texture was not affected by freezing temperature or scalding. Frozen octopus was softer after cooking than fresh. The longer the cooking time was, the softer the octopus was. Myosin heavy chain (MHC) was not significantly affected by scalding or cooking; however large aggregates heavier than MHC, new bands and loss of resolution of the bands appeared. Myosin and paramyosin bands were more affected by freezing prior to cooking.

  11. Static delectric behavior of charged fluids near freezing

    International Nuclear Information System (INIS)

    Fasolino, A.; Parrinello, M.; Tosi, M.P.

    1978-01-01

    The wavenumber-dependent, static dielectric function of classical charged fluids near freezing is obtained from structural data based on computer simulation or neutron diffraction, and its behavior is connected with the freezing process. (Auth.)

  12. Freezing nucleation apparatus puts new slant on study of biological ice nucleators in precipitation

    Science.gov (United States)

    Stopelli, E.; Conen, F.; Zimmermann, L.; Alewell, C.; Morris, C. E.

    2014-01-01

    For decades, drop-freezing instruments have contributed to a better understanding of biological ice nucleation and its likely implications for cloud and precipitation development. Yet, current instruments have limitations. Drops analysed on a cold stage are subject to evaporation and potential contamination. The use of closed tubes provides a partial solution to these problems, but freezing events are still difficult to be clearly detected. Here, we present a new apparatus where freezing in closed tubes is detected automatically by a change in light transmission upon ice development, caused by the formation of air bubbles and crystal facets that scatter light. Risks of contamination and introduction of biases linked to detecting the freezing temperature of a sample are then minimized. To illustrate the performance of the new apparatus we show initial results of two assays with snow samples. In one, we repeatedly analysed the sample (208 tubes) over the course of a month with storage at +4 °C, during which evidence for biological ice nucleation activity emerged through an increase in the number of ice nucleators active around -4 °C. In the second assay, we indicate the possibility of increasingly isolating a single ice nucleator from a precipitation sample, potentially determining the nature of a particle responsible for a nucleation activity measured directly in the sample. These two seminal approaches highlight the relevance of this handy apparatus for providing new points of view in biological ice nucleation research.

  13. Cryogenic freezing of fresh date fruits for quality preservation during frozen storage

    Directory of Open Access Journals (Sweden)

    Abdullah Alhamdan

    2018-01-01

    Full Text Available Fresh date fruits, especially Barhi cultivar, are favored and widely consumed at the Khalal maturity stage (first color edible stage. These fruits are seasonal and perishable and there is a need for extending their shelf life. This study evaluates two different freezing methods, namely cryogenic freezing using liquid nitrogen and conventional deep freezing on preserving the quality and stability of date fruits (cv. Barhi at Khalal maturity stage. Fresh date fruits (cv. Barhi at Khalal stage were frozen utilizing the two methods. The produced frozen dates were stored under frozen storage conditions for nine months (at −20 °C and −40 °C for the conventional and cryogenic freezing, respectively. Color values, textural properties (hardness, elasticity, chewiness and resilience, and nutrition attributes (enzymes and sugars for fresh dates before freezing and for the frozen dates were measured every three months during the frozen storage. Color values of the frozen dates were affected by the freezing method and the frozen storage period. There are substantial differences in the quality of the frozen fruits in favor of cryogenic freezing compared to the conventional slow freezing. The results revealed a large disparity between the times of freezing of the two methods. The freezing time accounted to 10 min in the cryogenic freezing method, whereas it was 1800 min for the conventional slow freezing system.

  14. Experimental analysis and modeling of ultrasound assisted freezing of potato spheres.

    Science.gov (United States)

    Kiani, Hossein; Zhang, Zhihang; Sun, Da-Wen

    2015-09-01

    In recent years, innovative methods such as ultrasound assisted freezing have been developed in order to improve the freezing process. During freezing of foods, accurate prediction of the temperature distribution, phase ratios, and process time is very important. In the present study, ultrasound assisted immersion freezing process (in 1:1 ethylene glycol-water solution at 253.15K) of potato spheres (0.02 m diameter) was evaluated using experimental, numerical and analytical approaches. Ultrasound (25 kHz, 890 W m(-2)) was irradiated for different duty cycles (DCs=0-100%). A finite volume based enthalpy method was used in the numerical model, based on which temperature and liquid fraction profiles were simulated by a program developed using OpenFOAM® CFD software. An analytical technique was also employed to calculate freezing times. The results showed that ultrasound irradiation could decrease the characteristic freezing time of potatoes. Since ultrasound irradiation increased the heat transfer coefficient but simultaneously generated heat at the surface of the samples, an optimum DC was needed for the shortest freezing time which occurred in the range of 30-70% DC. DCs higher than 70% increased the freezing time. DCs lower than 30% did not provide significant effects on the freezing time compared to the control sample. The numerical model predicted the characteristic freezing time in accordance with the experimental results. In addition, analytical calculation of characteristic freezing time exhibited qualitative agreement with the experimental results. As the numerical simulations provided profiles of temperature and water fraction within potatoes frozen with or without ultrasound, the models can be used to study and control different operation situations, and to improve the understanding of the freezing process. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Freeze-drying and related preparation techniques for biological microprobe analysis

    International Nuclear Information System (INIS)

    Wroblewski, R.; Wroblewski, J.; Anniko, M.; Edstroem, L.P.

    1985-01-01

    An X-ray microanalytical and morphological investigation has been carried out on rapidly frozen, freeze-dried or freeze-substituted tissues. A comparison was made between different embedding and polymerization procedures following freeze-substitution and freeze-drying. The investigation also included an analysis of specimens infiltrated, embedded and polymerized by ultraviolet irradiation at low temperatures with Lowicryl HM20. The morphological preservation of Lowicryl embedded tissue was adequate for the identification of different cell structures like nuclei, mitochondria, lysosomes and different types of endoplasmic reticulum. X-ray microanalytical investigation of low temperature embedded material displayed an elemental composition of cells and organelles similar to that found in freeze-dried cyosections. Compared with freeze-dried cryosections, low temperature embedded material could be sectioned for light microscopy and area of interest chosen for further thin sectioning. This is of great importance in work with tissues with complicated morphology and heterogenous cell populations

  16. Storage of human platelets by freezing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B K; Tanoue, K; Baldini, M G

    1976-01-01

    Prolonged, probably indefinite storage of viable and functional human platelets is now possible by freezing with dimethylsulfoxide (DMSO). The platelets have a nearly normal survival upon reinfusion and are capable of sustained hemostatic effectiveness in thrombocytopenic patients. Adaptation of the freezing technique for large-scale usage has more recently been achieved. The method is mainly based on the following principles: (1) use of plasma for suspension of the platelet concentrate; (2) gradual addition (0.5% every 2 min) of DMSO to a final concentration of 5% and its gradual removal; (3) a slow cooling rate of about 1/sup 0/C per min and rapid thawing (in 1 min); (4) use of a polyolefin plastic bag for freezing; (5) a washing medium of 20% plasma in Hanks' balanced salt solution; (6) final resuspension of the platelets in 50% plasma in Hanks' solution.

  17. Heterogeneous freezing of super cooled water droplets in micrometre range- freezing on a chip

    Science.gov (United States)

    Häusler, Thomas; Witek, Lorenz; Felgitsch, Laura; Hitzenberger, Regina; Grothe, Hinrich

    2017-04-01

    A new setup to analyse the freezing behaviour of ice nucleation particles (INPs) dispersed in aqueous droplets has been developed with the aim to analyse ensembles of droplets with sizes in the micrometre range, in which INPs are immersed. Major disadvantages of conventional drop-freezing experiments like varying drop sizes or interactions between the water- oil mixture and the INP, were solved by introducing a unique freezing- chip consisting of an etched and sputtered 15x15x1 mm gold-plated silicon or pure gold film (Pummer et al., 2012; Zolles et al., 2015). Using this chip, isolated micrometre-sized droplets can be generated with sizes similar to droplets in real world clouds. The experimental set-up for drop-freezing experiments was revised and improved by establishing automated process control and image evaluation. We were able to show the efficiency and accuracy of our setup by comparing measured freezing temperatures of different INPs (Snomax®, K- feldspar, birch pollen (Betula pendula) washing water, juniper pollen suspension (Juniperus communis) and ultrapure water) with already published results (Atkinson et al., 2013; Augustin et al., 2013; Pruppacher and Klett, 1997; Pummer et al., 2012; Wex et al., 2015; Zolles et al., 2015). Comparison of our measurements with literature data show the important impact of droplet size, INP concentration and number of active sites on the T50 values. Here, the new set-up exhibits its strength in reproducibility and accuracy which is due to the defined and isolated droplets. Finally, it opens a temperature window down to -37˚ C for freezing experiments which was not accessible with former traditional approaches .Atkinson, J. D., Murray, B. J., Woodhouse, M. T., Whale, T. F., Baustian, K. J., Carslaw, K. S., Dobbie, S., O'Sullivan, D., and Malkin, T. L.: The importance of feldspar for ice nucleation by mineral dust in mixed-phase clouds (vol 498, pg 355, 2013), Nature, 500, 491-491, 2013. Augustin, S., Wex, H

  18. Synthesis, processing behavior, and characterization of bismuth superconductors using freeze dried nitrate precursors

    International Nuclear Information System (INIS)

    Coppa, N.V.; Hults, W.L.; Smith, J.L.; Brynestad, J.

    1994-01-01

    The synthesis of Bi 2-x Pb x Sr 2 Ca 2 Cu 3 O 10 (Bi2223) powders from a freeze dried nitrate precursor is reported here. We examine the composition and morphology of the precursor material, describe the chemistry and kinetics of product formation, and evaluate the phase composition and superconducting properties of the products. A nitrate solution containing the appropriate ratio of cations was rapidly frozen and then freeze dried at low temperatures to form an atomic mixture of the component salts. The thermal processing of the freeze dried material consisted of three steps: (i) dehydration, (ii) denitration, and (iii) solid state reaction to form the Bi2223 superconducting product. Calcium substituted bismuthates and strontium-substituted calcium cuprate, not Bi2201, are the intermediates between the nitrates and the superconducting products. These highly disordered phases rapidly transform into Bi2212 or Bi2223 at higher temperatures (>790 degree C). The kinetics of product formation was studied using XRD analysis and magnetic susceptibility. The kinetics were shown to follow the nucleation and growth mechanism. Bi2223 formed after only 30 min at a few degrees below the melting point, and after 37 h Bi2223 products exhibited excellent phase composition and magnetic susceptibility characteristics

  19. Preparation of freezing quantum state for quantum coherence

    Science.gov (United States)

    Yang, Lian-Wu; Man, Zhong-Xiao; Zhang, Ying-Jie; Han, Feng; Du, Shao-jiang; Xia, Yun-Jie

    2018-06-01

    We provide a method to prepare the freezing quantum state for quantum coherence via unitary operations. The initial product state consists of the control qubit and target qubit; when it satisfies certain conditions, the initial product state converts into the particular Bell diagonal state under the unitary operations, which have the property of freezing of quantum coherence under quantum channels. We calculate the frozen quantum coherence and corresponding quantum correlations, and find that the quantities are determined by the control qubit only when the freezing phenomena occur.

  20. Freezing temperature protection admixture for Portland cement concrete

    Science.gov (United States)

    1996-10-01

    A number of experimental admixtures were compared to Pozzutec 20 admixture for their ability to protect fresh concrete from freezing and for increasing the rate of cement hydration at below-freezing temperatures. The commercial accelerator and low-te...

  1. Research on strength attenuation law of concrete in freezing - thawing environment

    Science.gov (United States)

    Xiao, qianhui; Cao, zhiyuan; Li, qiang

    2018-03-01

    By rapid freezing and thawing method, the experiments of concrete have been 300 freeze-thaw cycles specimens in the water. The cubic compression strength value under different freeze-thaw cycles was measured. By analyzing the test results, the water-binder ratio of the concrete under freeze-thaw environments, fly ash and air entraining agent is selected dosage recommendations. The exponential attenuation prediction model and life prediction model of compression strength of concrete under freezing-thawing cycles considering the factors of water-binder ratio, fly ash content and air-entraining agent dosage were established. The model provides the basis for predicting the durability life of concrete under freezing-thawing environment. It also provides experimental basis and references for further research on concrete structures with antifreeze requirements.

  2. Universal pion freeze-out in heavy-ion collisions.

    Science.gov (United States)

    Adamová, D; Agakichiev, G; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Castillo, A; Cherlin, A; Damjanović, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Z; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B; Ludolphs, W; Maas, A; Marín, A; Milosević, J; Milov, A; Miśkowiec, D; Panebrattsev, Yu; Petchenova, O; Petrácek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Sako, H; Schmitz, W; Schukraft, J; Sedykh, S; Shimansky, S; Slívová, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, I; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V

    2003-01-17

    Based on an evaluation of data on pion interferometry and on particle yields at midrapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda(f) reaches a value of about 1 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and beam energy from the Alternating Gradient Synchrotron to the Relativistic Heavy Ion Collider.

  3. Water vapor movement in freezing aggregate base materials.

    Science.gov (United States)

    2014-06-01

    The objectives of this research were to 1) measure the extent to which water vapor movement results in : water accumulation in freezing base materials; 2) evaluate the effect of soil stabilization on water vapor movement : in freezing base materials;...

  4. A freeze-stable formulation for DTwP and DTaP vaccines.

    Science.gov (United States)

    Xue, Honggang; Yang, Bangling; Kristensen, Debra D; Chen, Dexiang

    2014-01-01

    Inadvertent vaccine freezing often occurs in the cold chain and may cause damage to freeze‑sensitive vaccines. Liquid vaccines that contain aluminum salt adjuvants are particularly vulnerable. Polyol cryoprotective excipients have been shown to prevent freeze damage to hepatitis B vaccine. In this study, we examined the freeze-protective effect of propylene glycol on diphtheria-tetanus-pertussis-whole-cell (DTwP) and acellular (DTaP) vaccines. Pilot lots of DTwP and DTaP formulated with 7.5% propylene glycol underwent 3 freeze-thaw treatments. The addition of propylene glycol had no impact on pH, particle size distribution, or potency of the vaccines prior to freeze-thaw treatment; the only change noted was an increase in osmolality. The potencies and the physical properties of the vaccines containing cryoprotectant were maintained after freeze-thawing and for 3 months in accelerated stability studies. The results from this study indicate that formulating vaccines with propylene glycol can protect diphtheria-tetanus-pertussis vaccines against freeze damages.

  5. Freeze-drying-induced changes in the properties of graphene oxides

    International Nuclear Information System (INIS)

    Ham, Heon; Van Khai, Tran; Gil Na, Han; Jung Kwon, Yong; Yeon Cho, Hong; Woo Kim, Hyoun; Park, No-Hyung; So, Dae Sup; Lee, Joon-Woo

    2014-01-01

    We have characterized and evaluated changes in graphene oxide (GO) induced by means of freeze-drying. In order to evaluate these changes, we investigated the effects of freeze-drying and chemical reduction processes on the structure, morphology, chemical composition, and Raman properties of GO and reduced GO. The freeze-dried GO had a pore structure, maintaining a pored morphology even after thermal annealing. The freeze-dried samples were composed of a single folded nanosheet or a few nanosheets stacked and folded. The oxygen-containing functional groups were removed not only during the freeze-drying but also during the reduction processes, with an accompanying decrease in the average size of the sp 2 carbon domain (i.e. an increase in the I D /I G value). (papers)

  6. Nanocrystals-based Macroporous Materials Synthesized by Freeze-drying Combustion

    International Nuclear Information System (INIS)

    Yan, Ruiqiang; Chen, Yu; Lin, Ye; Chen, Fanglin

    2016-01-01

    We present a novel freeze-drying combustion method for synthesis of macroporous powders with nano-network, using Sm 0.2 Ce 0.8 O 1.9 (SDC) as an example. The metal nitrate salt solution mixed with glycine is frozen to form homogeneous nitrate/glycine mixture and then freeze-dried through sublimation of ice crystals. Upon combustion of the freeze-dried mixture, SDC powders with macroporous microstructure consisting of 10–20 nm nanocrystals, high surface area and excellent sinterability are achieved. High resolution transmission electron microscopy (HRTEM) analysis indicates that nanodomains due to aggregation/segregation of dopants in the SDC powders obtained from freeze-drying combustion are much smaller than those in the SDC powders synthesized by the conventional nitrate solution combustion approach, demonstrating better elemental homogeneity and improved conductivity. Using low cost precursors and simple processing conditions, freeze-drying combustion can be a versatile method to synthesize nanocrystalline powders with excellent composition homogeneity for broad applications.

  7. RESEARCH OF MOISTURE MIGRATION DURING PARTIAL FREEZING OF GROUND BEEF

    Directory of Open Access Journals (Sweden)

    V. M. Stefanovskiy

    2016-01-01

    Full Text Available The concept of «ideal product» is proposed for the study of mass transfer during partial freezing of food products by freezing plate. The ideal product is a product, in which number of factors affecting the «real product» (meat are excluded. These factors include chemical composition of meat, quality grade of raw material (NOR, DFD, PSE, cryoscopic temperature that determines the degree of water transformation into ice, the phenomenon of osmosis, rate of freezing, etc. By using the concept of «ideal product» and its implementation in a physical experiment, it is proved that the “piston effect” causing the migration of moisture is due to frozen crust formation during partial freezing of the body. During partial freezing of the product by freezing plate, «ideal» and «real» food environment is transformed from closed system into open one with inflow of moisture to unfrozen part of the body. In the «ideal product», there is an expulsion of unfrozen moisture from freezing front, so the water appears on the body surface. Thus, the displacement of moisture increases by the same law, according to which the thickness (weight of frozen layer increases. During partial freezing of ground meat, moisture does not appear on the surface of the product, but hydrates the unfrozen part of meat. The reason of this phenomenon is the expulsion of water during formation of frozen crust and water-binding capacity of meat.

  8. Vapor Pressure Plus: An Experiment for Studying Phase Equilibria in Water, with Observation of Supercooling, Spontaneous Freezing, and the Triple Point

    Science.gov (United States)

    Tellinghuisen, Joel

    2010-01-01

    Liquid-vapor, solid-vapor, and solid-liquid-vapor equilibria are studied for the pure substance water, using modern equipment that includes specially fabricated glass cells. Samples are evaporatively frozen initially, during which they typically supercool to -5 to -10 [degrees]C before spontaneously freezing. Vacuum pumping lowers the temperature…

  9. Levels of some trace elements in serum of esophageal cancer patients

    Energy Technology Data Exchange (ETDEWEB)

    Saeed, D M. A. [Sudan Academy of Sciences, Atomic Energy Council, Khartoum (Sudan)

    2011-01-15

    The aim of this study is to measure the concentrations of six trace elements (Zn, Se, Fe, Co, Rb, Hg) in the serum of patients with esophageal cancer who were newly diagnosed before undergoing any type of treatment. Biopsy was taken from diseased esophagus and examined histologically. A total of 43 samples of patients and 36 samples from healthy control group was collected, which were then dried by freeze drying. Then analyzed by neutron activation analysis technology, using research reactor in Syria (the miniature neutron source, MNSR) with neutron flux of 1x10''1''2 n.cm ''-''2 s''-''1 was performed. Certified reference sample from the International Agency were obtained for quality control analysis to ensure the reliability of the device. All six elements were statistically analyzed, the study proved statistical significant difference concentration of following five elements, Zn, Se, Fe, Co, Rb in the serum of patients compared to the serum samples of healthy people. The concentration of Zn and Se in patients serum were less compared to serum of healthy individuals, and the concentrations of Fe, Co, Rb in serum of patients were higher than its that the serum of healthy individuals. While the concentrations of Hg was found to be higher in serum of healthy individuals compared to patients serum, but without statistical significant. The concentration presented by means with standard deviation. The findings were compared to results obtained from literature. All five elements compatible with literature. Hg has not been investigated in such studies before. Selenium and zinc supplementation are need by cancer patient in order to enhance and increase the chances for natural immunological of cancer.(Author)

  10. Levels of some trace elements in serum of esophageal cancer patients

    International Nuclear Information System (INIS)

    Saeed, D. M. A.

    2011-01-01

    The aim of this study is to measure the concentrations of six trace elements (Zn, Se, Fe, Co, Rb, Hg) in the serum of patients with esophageal cancer who were newly diagnosed before undergoing any type of treatment. Biopsy was taken from diseased esophagus and examined histologically. A total of 43 samples of patients and 36 samples from healthy control group was collected, which were then dried by freeze drying. Then analyzed by neutron activation analysis technology, using research reactor in Syria (the miniature neutron source, MNSR) with neutron flux of 1x10''1''2 n.cm ''-''2 s''-''1 was performed. Certified reference sample from the International Agency were obtained for quality control analysis to ensure the reliability of the device. All six elements were statistically analyzed, the study proved statistical significant difference concentration of following five elements, Zn, Se, Fe, Co, Rb in the serum of patients compared to the serum samples of healthy people. The concentration of Zn and Se in patients serum were less compared to serum of healthy individuals, and the concentrations of Fe, Co, Rb in serum of patients were higher than its that the serum of healthy individuals. While the concentrations of Hg was found to be higher in serum of healthy individuals compared to patients serum, but without statistical significant. The concentration presented by means with standard deviation. The findings were compared to results obtained from literature. All five elements compatible with literature. Hg has not been investigated in such studies before. Selenium and zinc supplementation are need by cancer patient in order to enhance and increase the chances for natural immunological of cancer.(Author)

  11. Enhanced resolution of membranes in cultured cells by cryoimmobilization and freeze-substitution.

    Science.gov (United States)

    Wild, P; Schraner, E M; Adler, H; Humbel, B M

    2001-05-15

    Investigations of cellular processes demand immediate arresting of the process at any given time and excellent retention of cellular material and excellent visibility of membranes. To achieve this goal we used cryofixation to arrest cellular processes instantly and tested diverse freeze-substitution protocols. Madin-Darby kidney cells and Vero cells were grown on carbon-coated sapphire disks. For cryofixation the sapphire disks covered with a cell monolayer were injected with the aid of a guillotine into liquid propane or ethane or a mixture of both cooled by liquid nitrogen. Freezing of the cryogen was prevented by using a partially insulated cylinder and by vigorous stirring that results in a substantial decrement of the freezing point of the cryogen. Cell monolayers can be cryofixed successfully using the guillotine in a safety hood at ambient temperature and humidity or at 37 degrees C and 45% humidity. The freezing unit can also be placed in a laminar flow for working under biohazard conditions. For visualizing cell membranes at high contrast and high resolution, cells were substituted in the presence of various concentrations of glutaraldehyde and osmium tetroxide and the temperature was raised to diverse final temperatures. Substitution for 4 hours at -90 degrees C in anhydrous acetone containing 0.25% anhydrous glutaraldehyde and 0.5% osmium tetroxide followed by a temperature rise of 5 degrees C/hour to 0 degrees C and final incubation for 1 hour at 0 degrees C resulted in high contrast and excellent visibility of subcellular components at the level of the membrane bilayer. The high spatial and temporal resolution makes this methodology an excellent tool for studying cell membrane-bound processes, such as virus-cell interactions. Copyright 2001 Wiley-Liss, Inc.

  12. Freeze injury to roots of southern pine seedlings in the USA | South ...

    African Journals Online (AJOL)

    ... and therefore root injury was often overlooked. Many freeze-injured seedlings died within two months of the freeze event. Since freeze injury symptoms to roots were overlooked, foresters offered various reasons (other than the freeze) for the poor seedling performance. Keywords: acclimation, frost, nursery, Pinus elliottii, ...

  13. Brown bear sperm double freezing: Effect of elapsed time and use of PureSperm(®) gradient between freeze-thaw cycles.

    Science.gov (United States)

    Alvarez-Rodríguez, Manuel; Alvarez, Mercedes; López-Urueña, Elena; Martínez-Rodriguez, Carmen; Borragan, Santiago; Anel-López, Luis; de Paz, Paulino; Anel, Luis

    2013-12-01

    The use of sexed spermatozoa has great potential to captive population management in endangered wildlife. The problem is that the sex-sorting facility is a long distance from the semen collection place and to overcome this difficulty two freeze-thaw cycles may be necessary. In this study, effects of refreezing on brown bear electroejaculated spermatozoa were analyzed. We carried out two experiments: (1) to assess the effects of the two freezing-thawing cycles on sperm quality and to analyze three different elapsed times between freezing-thawing cycles (30, 90 and 180 min), and (2) to analyze the use of PureSperm between freezing-thawing cycles to select a more motile and viable sperm subpopulation which better survived first freezing. The motility, viability and undamaged acrosomes were significantly reduced after the second thawing respect to first thawing into each elapsed time group, but the elapsed times did not significantly affect the viability and acrosome status although motility was damaged. Our results with the PureSperm gradient showed higher values of viability in freezability of select sample (pellet) respect to the rest of the groups and it also showed a significant decrease in the number of acrosome damaged. In summary, the double freezing of bear semen selected by gradient centrifugation is qualitatively efficient, and thus could be useful to carry out a sex-sorting of frozen-thawed bear spermatozoa before to send the cryopreserved sample to a biobank. Given the low recovery of spermatozoa after applying a selection gradient, further studies will be needed to increase the recovery rate without damaging of the cell quality. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Multi-scale validation of a new soil freezing scheme for a land-surface model with physically-based hydrology

    Directory of Open Access Journals (Sweden)

    I. Gouttevin

    2012-04-01

    Full Text Available Soil freezing is a major feature of boreal regions with substantial impact on climate. The present paper describes the implementation of the thermal and hydrological effects of soil freezing in the land surface model ORCHIDEE, which includes a physical description of continental hydrology. The new soil freezing scheme is evaluated against analytical solutions and in-situ observations at a variety of scales in order to test its numerical robustness, explore its sensitivity to parameterization choices and confront its performance to field measurements at typical application scales.

    Our soil freezing model exhibits a low sensitivity to the vertical discretization for spatial steps in the range of a few millimetres to a few centimetres. It is however sensitive to the temperature interval around the freezing point where phase change occurs, which should be 1 °C to 2 °C wide. Furthermore, linear and thermodynamical parameterizations of the liquid water content lead to similar results in terms of water redistribution within the soil and thermal evolution under freezing. Our approach does not allow firm discrimination of the performance of one approach over the other.

    The new soil freezing scheme considerably improves the representation of runoff and river discharge in regions underlain by permafrost or subject to seasonal freezing. A thermodynamical parameterization of the liquid water content appears more appropriate for an integrated description of the hydrological processes at the scale of the vast Siberian basins. The use of a subgrid variability approach and the representation of wetlands could help capture the features of the Arctic hydrological regime with more accuracy.

    The modeling of the soil thermal regime is generally improved by the representation of soil freezing processes. In particular, the dynamics of the active layer is captured with more accuracy, which is of crucial importance in the prospect of

  15. DSC and TMA studies on freezing and thawing gelation of galactomannan polysaccharide

    International Nuclear Information System (INIS)

    Iijima, Mika; Hatakeyama, Tatsuko; Hatakeyama, Hyoe

    2012-01-01

    Research highlights: ► Locust bean gum forms hydrogels by freezing and thawing. ► Syneresis was observed when freezing and thawing cycle (n) increased. ► Dynamic Young's modulus increased with increasing n. ► Non-freezing water content restrained by hydrogels decreased with increasing n. ► Strong gel with densely packed network structure formed with increasing n. - Abstract: Among various kinds of polysaccharides known to form hydrogels, locust bean gum (LBG) consisting of a mannose backbone and galactose side chains has unique characteristics, since LBG forms hydrogels by freezing and thawing. In this study, effect of thermal history on gelation was investigated by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). Gel/sol ratio calculated by weighing method was found to be affected by sol concentration, freezing rate and the number of freezing and thawing cycle (n). Once LBG hydrogels are formed, they are thermally stable, although syneresis was observed when n increased. Dynamic Young's modulus (E′) of hydrogels measured by TMA in water increased with increasing n and decreasing freezing rate. Non-freezing water calculated from DSC melting peak of ice in the gel decreased with increasing n and decreasing freezing rate. Morphological observation of freeze-dried gels was carried out by scanning electron microscopy (SEM). The above results indicate that weak hydrogel having large molecular network structure transformed into strong gel with densely packed network structure by increasing n and decreasing freezing rate.

  16. Freezing and low temperature photoinhibition tolerance in cultivated potato and potato hybrids

    Directory of Open Access Journals (Sweden)

    M.M. SEPPÄNEN

    2008-12-01

    Full Text Available Four Solanum tuberosum L. cultivars (Nicola, Pito, Puikula, Timo and somatic hybrids between freezing tolerant S. commersonii and freezing sensitive S. tuberosum were evaluated for their tolerance to freezing and low temperature photoinhibition. Cellular freezing tolerance was studied using ion leakage tests and the sensitivity of the photosynthetic apparatus to freezing and high light intensity stress by measuring changes in chlorophyll fluorescence (FV/FM and oxygen evolution. Exposure to high light intensities after freezing stress increased frost injury significantly in all genotypes studied. Compared with S. tuberosum cultivars, the hybrids were more tolerant both of freezing and intense light stresses. In field experiments the mechanism of frost injury varied according to the severity of night frosts. During night frosts in 1999, the temperature inside the potato canopy was significantly higher than at ground level, and did not fall below the lethal temperature for potato cultivars (from -2.5 to -3.0°C. As a result, frost injury developed slowly, indicating that damage occurred to the photosynthetic apparatus. However, as the temperature at ground level and inside the canopy fell below -4°C, cellular freezing occurred and the canopy was rapidly destroyed. This suggests that in the field visual frost damage can follow from freezing or non-freezing temperatures accompanied with high light intensity. Therefore, in an attempt to improve low temperature tolerance in potato, it is important to increase tolerance to both freezing and chilling stresses.

  17. A comparative evaluation of freeze dried bone allograft and decalcified freeze dried bone allograft in the treatment of intrabony defects: A clinical and radiographic study

    Directory of Open Access Journals (Sweden)

    Rajat Gothi

    2015-01-01

    Full Text Available Background: Ideal graft material for regenerative procedures is autogenous bone graft but the major disadvantage with this graft is the need for a secondary surgical site to procure donor material and the frequent lack of intraoral donor site to obtain sufficient quantities of autogenous bone for multiple or deep osseous defects. Hence, to overcome these disadvantages, bone allografts were developed as an alternative source of graft material. Materials and Methods: In 10 patients with chronic periodontitis, 20 bilateral infrabony defects were treated with freeze dried bone allograft (FDBA-Group A and decalcified freeze dried bone allograft (DFDBA-Group B. Clinical and radiographic parameters were assessed preoperatively and at 3 months and 6 months postoperatively. Data thus obtained was subjected to statistical analysis. Results: Significant improvement in the reduction in probing depth and relative attachment level (RAL from the baseline to 3 months to baseline to 6 months in group A and group B, which was statistically significant but no statistically significant reduction was seen between 3 months and 6 months. On inter-group comparison, no significant differences were observed at all-time points. In adjunct to the probing depth and RAL, the radiographic area of the defect showed a similar trend in intra-group comparison and no significant difference was seen on inter-group comparison at all-time points. Conclusions: Within the limitations of the current study, it can be concluded that DFDBA did not show any improvement in the clinical and radiographic parameters in the treatment of the intrabony defects as compared to FDBA.

  18. Freezing tolerance of ectomycorrhizal fungi in pure culture.

    Science.gov (United States)

    Lehto, Tarja; Brosinsky, Arlena; Heinonen-Tanski, Helvi; Repo, Tapani

    2008-10-01

    The ability to survive freezing and thawing is a key factor for the existence of life forms in large parts of the world. However, little is known about the freezing tolerance of mycorrhizal fungi and their role in the freezing tolerance of mycorrhizas. Threshold temperatures for the survival of these fungi have not been assessed experimentally. We grew isolates of Suillus luteus, Suillus variegatus, Laccaria laccata, and Hebeloma sp. in liquid culture at room temperature. Subsequently, we exposed samples to a series of temperatures between +5 degrees C and -48 degrees C. Relative electrolyte leakage (REL) and re-growth measurements were used to assess the damage. The REL test indicated that the lethal temperature for 50% of samples (LT(50)) was between -8.3 degrees C and -13.5 degrees C. However, in the re-growth experiment, all isolates resumed growth after exposure to -8 degrees C and higher temperatures. As many as 64% of L. laccata samples but only 11% in S. variegatus survived -48 degrees C. There was no growth of Hebeloma and S. luteus after exposure to -48 degrees C, but part of their samples survived -30 degrees C. The fungi tolerated lower temperatures than was expected on the basis of earlier studies on fine roots of ectomycorrhizal trees. The most likely freezing tolerance mechanism here is tolerance to apoplastic freezing and the concomitant intracellular dehydration with consequent concentrating of cryoprotectant substances in cells. Studying the properties of fungi in isolation promotes the understanding of the role of the different partners of the mycorrhizal symbiosis in the freezing tolerance.

  19. CONSIDERA TIONS OF ICE MORPHOLOGY AND DRIVING FORCES IN FREEZE CONCENTRATION

    OpenAIRE

    PETZOLD MALDONADO, GUILLERMO

    2013-01-01

    Ice rnorphology (size and shape) influence decisively in sensory appreciation, texture and quality of rnany frozen foods. Ice rnorphology is also irnportant in sorne technological processes such as freeze drying and freeze concentration, which influences the efficiency ofthese processes. The overall objective of this thesis was to increase our knowledge about the control on rnorphology of the ice phase in freezing food and related processes such as freeze concentration. Freezin...

  20. Dynamic freeze-in: impact of thermal masses and cosmological phase transitions on dark matter production

    Science.gov (United States)

    Baker, Michael J.; Breitbach, Moritz; Kopp, Joachim; Mittnacht, Lukas

    2018-03-01

    The cosmological abundance of dark matter can be significantly influenced by the temperature dependence of particle masses and vacuum expectation values. We illustrate this point in three simple freeze-in models. The first one, which we call kinematically induced freeze-in, is based on the observation that the effective mass of a scalar temporarily becomes very small as the scalar potential undergoes a second order phase transition. This opens dark matter production channels that are otherwise forbidden. The second model we consider, dubbed vev-induced freeze-in, is a fermionic Higgs portal scenario. Its scalar sector is augmented compared to the Standard Model by an additional scalar singlet, S, which couples to dark matter and temporarily acquires a vacuum expectation value (a two-step phase transition or "vev flip-flop"). While ≠ 0, the modified coupling structure in the scalar sector implies that dark matter production is significantly enhanced compared to the = 0 phases realised at very early times and again today. The third model, which we call mixing-induced freeze-in, is similar in spirit, but here it is the mixing of dark sector fermions, induced by non-zero , that temporarily boosts the dark matter production rate. For all three scenarios, we carefully dissect the evolution of the dark sector in the early Universe. We compute the DM relic abundance as a function of the model parameters, emphasising the importance of thermal corrections and the proper treatment of phase transitions in the calculation.

  1. Potential of Near-Infrared Chemical Imaging as Process Analytical Technology Tool for Continuous Freeze-Drying.

    Science.gov (United States)

    Brouckaert, Davinia; De Meyer, Laurens; Vanbillemont, Brecht; Van Bockstal, Pieter-Jan; Lammens, Joris; Mortier, Séverine; Corver, Jos; Vervaet, Chris; Nopens, Ingmar; De Beer, Thomas

    2018-04-03

    Near-infrared chemical imaging (NIR-CI) is an emerging tool for process monitoring because it combines the chemical selectivity of vibrational spectroscopy with spatial information. Whereas traditional near-infrared spectroscopy is an attractive technique for water content determination and solid-state investigation of lyophilized products, chemical imaging opens up possibilities for assessing the homogeneity of these critical quality attributes (CQAs) throughout the entire product. In this contribution, we aim to evaluate NIR-CI as a process analytical technology (PAT) tool for at-line inspection of continuously freeze-dried pharmaceutical unit doses based on spin freezing. The chemical images of freeze-dried mannitol samples were resolved via multivariate curve resolution, allowing us to visualize the distribution of mannitol solid forms throughout the entire cake. Second, a mannitol-sucrose formulation was lyophilized with variable drying times for inducing changes in water content. Analyzing the corresponding chemical images via principal component analysis, vial-to-vial variations as well as within-vial inhomogeneity in water content could be detected. Furthermore, a partial least-squares regression model was constructed for quantifying the water content in each pixel of the chemical images. It was hence concluded that NIR-CI is inherently a most promising PAT tool for continuously monitoring freeze-dried samples. Although some practicalities are still to be solved, this analytical technique could be applied in-line for CQA evaluation and for detecting the drying end point.

  2. Universal pion freeze-out in heavy-ion collisions

    CERN Document Server

    Adamova, D; Appelshäuser, H; Belaga, V; Braun-Munzinger, P; Castillo, A; Cherlin, A; Damjanovic, S; Dietel, T; Dietrich, L; Drees, A; Esumi, S I; Filimonov, K; Fomenko, K; Fraenkel, Zeev; Garabatos, C; Glässel, P; Hering, G; Holeczek, J; Kushpil, V; Lenkeit, B C; Ludolphs, W; Maas, A; Marin, A; Milosevic, J; Milov, A; Miskowiec, D; Panebratsev, Yu A; Petchenova, O Yu; Petracek, V; Pfeiffer, A; Rak, J; Ravinovich, I; Rehak, P; Sako, H; Schükraft, Jürgen; Sedykh, S; Shimansky, S S; Slivova, J; Specht, H J; Stachel, J; Sumbera, M; Tilsner, H; Tserruya, Itzhak; Wessels, J P; Wienold, T; Windelband, B; Wurm, J P; Xie, W; Yurevich, S; Yurevich, V; Schmitz, W

    2003-01-01

    Based on an evaluation of recent systematic data on two-pion interferometry and on measured particle yields at mid-rapidity, we propose a universal condition for thermal freeze-out of pions in heavy-ion collisions. We show that freeze-out occurs when the mean free path of pions lambda_f reaches a value of approximately 2.5 fm, which is much smaller than the spatial extent of the system at freeze-out. This critical mean free path is independent of the centrality of the collision and its value is constant at all currently available beam energies from AGS to RHIC.

  3. Anti-freezing of air-cooled heat exchanger by switching off sectors

    International Nuclear Information System (INIS)

    Wang, Weijia; Kong, Yanqiang; Huang, Xianwei; Yang, Lijun; Du, Xiaoze; Yang, Yongping

    2017-01-01

    Highlights: • The anti-freezing of air-cooled heat exchanger by switching off sectors is studied. • The water side heat loads of various sectors are compared for different cases. • Anti-freezing turbine back pressure is proposed and obtained for various cases. • As wind speed increases, the energy efficiency can be clearly improved by sector off. • By switching frontal sector off, anti-freezing operation is most energy efficient. - Abstract: With the air side huge heat transfer surface, the air-cooled heat exchanger will take a serious freezing risk in cold winter. Therefore, it is of benefit to the safe operation of natural draft dry cooling system to propose the anti-freezing measures. In this work, the flow and heat transfer models of the cooling air coupling with the circulating water, are developed and numerically simulated for the anti-freezing by switching various sectors off. The local thermo-flow fields of cooling air are presented, and the water side heat loads of various sectors are compared for various cases. The anti-freezing turbine back pressure is proposed and obtained for the energy efficiency analysis. The results show that the sector switching off approach can effectively prevent the air-cooled heat exchanger from freezing and improve the energy efficiency of the cooling system, especially at high wind speeds. Moreover, with the frontal sector switching off, the most energy efficient anti-freezing operation of natural draft dry cooling system can be achieved.

  4. Serum amyloid A isoforms in serum and synovial fluid from spontaneously diseased dogs with joint diseases or other conditions

    DEFF Research Database (Denmark)

    Kjelgaard-Hansen, Mads Jens; Christensen, Michelle B.; Lee, Marcel Huisung

    2007-01-01

    Serum amyloid A (SAA) is a major acute phase protein in dogs. However, knowledge of qualitative properties of canine SAA and extent of its synthesis in extrahepatic tissues is limited. The aim of the study was to investigate expression of different SAA isoforms in serum and synovial fluid...... in samples obtained from dogs (n = 16) suffering from different inflammatory or non-inflammatory conditions, which were either related or unrelated to joints. Expression of SAA isoforms was visualized by denaturing isoelectric focusing and Western blotting. Serum amyloid A was present in serum from all dogs...... with systemic inflammatory activity, and up to four major isoforms with apparent isoelectric points between 6.1 and 7.9 were identified. In synovial fluid from inflamed joints one or more highly alkaline SAA isoforms (with apparent isoelectric points above 9.3) were identified, with data suggesting local...

  5. Reduced freezing in posttraumatic stress disorder patients while watching affective pictures

    NARCIS (Netherlands)

    Fragkaki, I.; Roelofs, K.; Stins, J.F.; Jongedijk, R.A.; Hagenaars, M.A.

    2017-01-01

    Besides fight and flight responses, animals and humans may respond to threat with freezing, an adaptive response characterized by bradycardia and physical immobility. Risk assessment is enhanced during freezing to promote optimal decision-making. Indeed, healthy participants showed freezing-like

  6. Apparatus for freeze drying of biologic and sediment samples

    International Nuclear Information System (INIS)

    Anon.

    1978-01-01

    Freeze drying to obtain water from individual samples, though not complicated, usually requires considerable effort to maintain the cold traps on a 24-hr basis. In addition, the transfer of a sample from sample containers to freeze-dry flasks is usually made with some risk of contamination to the sample. If samples are large, 300 g to 600 g, usually several days are required to dry the samples. The use of an unattended system greatly improves personnel and drying efficiency. Commercial freeze dryers are not readily applicable to the problems of collecting water from individual samples, and lab-designed collectors required sample transfer and continual replenishment of the dry ice. A freeze-dry apparatus for collecting water from individual sediment and/or biological samples was constructed to determine the tritium concentrations in fish for dose calcaluations and the tritium distribution in sediment cores for water movement studies. The freeze, dry apparatus, which can handle eight samples simultaneously and conveniently, is set up for unattended 24-hr operation and is designed to avoid sample transfer problems

  7. Comparison Study of Three Common Technologies for Freezing-Thawing Measurement

    Directory of Open Access Journals (Sweden)

    Xinbao Yu

    2010-01-01

    Full Text Available This paper describes a comparison study on three different technologies (i.e., thermocouple, electrical resistivity probe and Time Domain Reflectometry (TDR that are commonly used for frost measurement. Specially, the paper developed an analyses procedure to estimate the freezing-thawing status based on the dielectric properties of freezing soil. Experiments were conducted where the data of temperature, electrical resistivity, and dielectric constant were simultaneously monitored during the freezing/thawing process. The comparison uncovered the advantages and limitations of these technologies for frost measurement. The experimental results indicated that TDR measured soil dielectric constant clearly indicates the different stages of the freezing/thawing process. Analyses method was developed to determine not only the onset of freezing or thawing, but also the extent of their development. This is a major advantage of TDR over other technologies.

  8. Adaptive Control of Freeze-Form Extrusion Fabrication Processes (Preprint)

    National Research Council Canada - National Science Library

    Zhao, Xiyue; Landers, Robert G; Leu, Ming C

    2008-01-01

    Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing process that extrudes high solids loading aqueous ceramic pastes in a layer-by-layer fashion below the paste freezing temperature for component fabrication...

  9. "On" freezing in Parkinson's disease: resistance to visual cue walking devices.

    Science.gov (United States)

    Kompoliti, K; Goetz, C G; Leurgans, S; Morrissey, M; Siegel, I M

    2000-03-01

    To measure "on" freezing during unassisted walking (UW) and test if two devices, a modified inverted stick (MIS) and a visual laser beam stick (LBS) improved walking speed and number of "on" freezing episodes in patients with Parkinson's disease (PD). Multiple visual cues can overcome "off' freezing episodes and can be useful in improving gait function in parkinsonian patients. These devices have not been specifically tested in "on" freezing, which is unresponsive to pharmacologic manipulations. Patients with PD, motor fluctuations and freezing while "on," attempted walking on a 60-ft track with each of three walking conditions in a randomized order: UW, MIS, and LBS. Total time to complete a trial, number of freezes, and the ratio of walking time to the number of freezes were compared using Friedman's test. Twenty-eight patients with PD, mean age 67.81 years (standard deviation [SD] 7.54), mean disease duration 13.04 years (SD 7.49), and mean motor Unified Parkinson's Disease Rating Scale score "on" 32.59 (SD 10.93), participated in the study. There was a statistically significant correlation of time needed to complete a trial and number of freezes for all three conditions (Spearman correlations: UW 0.973, LBS 0.0.930, and MIS 0.842). The median number of freezes, median time to walk in each condition, and median walking time per freeze were not significantly different in pairwise comparisons of the three conditions (Friedman's test). Of the 28 subjects, six showed improvement with the MIS and six with the LBS in at least one outcome measure. Assisting devices, specifically based on visual cues, are not consistently beneficial in overcoming "on" freezing in most patients with PD. Because this is an otherwise untreatable clinical problem and because occasional subjects do respond, cautious trials of such devices under the supervision of a health professional should be conducted to identify those patients who might benefit from their long-term use.

  10. Frost heave susceptibility of saturated soil under constant rate of freezing

    Science.gov (United States)

    Ryokai, K.; Iguro, M.; Yoneyama, K.

    Introduced are the results of experiments carried out to quantitatively obtain the frost heave pressure and displacement of soil subjected to artificial freezing or freezing around in-ground liquefied natural gas storage tanks. This experiment is conducted to evaluate the frost heave susceptibility of saturated soil under overconsolidation. In other words, this experiment was carried out to obtain the relation of the over-burden pressure and freezing rate to the frost heave ratio by observing the frost heave displacement and freezing time of specimens by freezing the specimens at a constant freezing rate under a constant overburden pressure, while letting water freely flow in and out of the system. Introduced are the procedures for frost heave test required to quantitatively obtain the frost heave displacement and pressure of soil. Furthermore, the relation between the frost heave susceptibility and physical properties of soil obtained by this test is reported.

  11. Gradient porous hydroxyapatite ceramics fabricated by freeze casting method

    International Nuclear Information System (INIS)

    Zuo Kaihui; Zhang Yuan; Jiang Dongliang; Zeng Yuping

    2011-01-01

    By controlling the cooling rates and the composition of slurries, the gradient porous hydroxyapatite ceramics are fabricated by the freeze casting method. According to the different cooling rate, the pores of HAP ceramics fabricated by gradient freeze casting are divided into three parts: one is lamellar pores, another is column pore and the last one is fine round pores. The laminated freeze casting is in favour of obtaining the gradient porous ceramics composed of different materials and the ceramics have unclear interfaces.

  12. Fabrication of a mini multi-fixed-point cell for the calibration of industrial platinum resistance thermometers

    Science.gov (United States)

    Ragay-Enot, Monalisa; Lee, Young Hee; Kim, Yong-Gyoo

    2017-07-01

    A mini multi-fixed-point cell (length 118 mm, diameter 33 mm) containing three materials (In-Zn eutectic (mass fraction 3.8% Zn), Sn and Pb) in a single crucible was designed and fabricated for the easy and economical fixed-point calibration of industrial platinum resistance thermometers (IPRTs) for use in industrial temperature measurements. The melting and freezing behaviors of the metals were investigated and the phase transition temperatures were determined using a commercial dry-block calibrator. Results showed that the melting plateaus are generally easy to realize and are reproducible, flatter and of longer duration. On the other hand, the freezing process is generally difficult, especially for Sn, due to the high supercooling required to initiate freezing. The observed melting temperatures at optimum set conditions were 143.11 °C (In-Zn), 231.70 °C (Sn) and 327.15 °C (Pb) with expanded uncertainties (k  = 2) of 0.12 °C, 0.10 °C and 0.13 °C, respectively. This multi-fixed-point cell can be treated as a sole reference temperature-generating system. Based on the results, the realization of melting points of the mini multi-fixed-point cell can be recommended for the direct calibration of IPRTs in industrial applications without the need for a reference thermometer.

  13. Use of freeze-casting in advanced burner reactor fuel design

    Energy Technology Data Exchange (ETDEWEB)

    Lang, A. L.; Yablinsky, C. A.; Allen, T. R. [Dept. of Engineering Physics, Univ. of Wisconsin Madison, 1500 Engineering Drive, Madison, WI 53711 (United States); Burger, J.; Hunger, P. M.; Wegst, U. G. K. [Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755 (United States)

    2012-07-01

    This paper will detail the modeling of a fast reactor with fuel pins created using a freeze-casting process. Freeze-casting is a method of creating an inert scaffold within a fuel pin. The scaffold is created using a directional solidification process and results in open porosity for emplacement of fuel, with pores ranging in size from 300 microns to 500 microns in diameter. These pores allow multiple fuel types and enrichments to be loaded into one fuel pin. Also, each pore could be filled with varying amounts of fuel to allow for the specific volume of fission gases created by that fuel type. Currently fast reactors, including advanced burner reactors (ABR's), are not economically feasible due to the high cost of operating the reactors and of reprocessing the fuel. However, if the fuel could be very precisely placed, such as within a freeze-cast scaffold, this could increase fuel performance and result in a valid design with a much lower cost per megawatt. In addition to competitive costs, freeze-cast fuel would also allow for selective breeding or burning of actinides within specific locations in fast reactors. For example, fast flux peak locations could be utilized on a minute scale to target specific actinides for transmutation. Freeze-cast fuel is extremely flexible and has great potential in a variety of applications. This paper performs initial modeling of freeze-cast fuel, with the generic fast reactor parameters for this model based on EBR-II. The core has an assumed power of 62.5 MWt. The neutronics code used was Monte Carlo N-Particle (MCNP5) transport code. Uniform pore sizes were used in increments of 100 microns. Two different freeze-cast scaffold materials were used: ceramic (MgO-ZrO{sub 2}) and steel (SS316L). Separate models were needed for each material because the freeze-cast ceramic and metal scaffolds have different structural characteristics and overall porosities. Basic criticality results were compiled for the various models

  14. Immunomodulatory effects of supercritical fluid CO2 extracts from freeze-dried powder of Tenebrio molitor larvae (yellow mealworm

    Directory of Open Access Journals (Sweden)

    QingFeng TANG

    2016-01-01

    Full Text Available Abstract In order to take full advantage of Tenebrio molitor larvae (yellow mealworm resources, the supercritical CO2 fluid freeze-dried powder of T. molitor larvae (fdTML extraction on the immune systems of mice was carried out. The results about the effects of supercritical CO2 fluid fdTML extraction on carbon expurgation and phagocytosis of peritoneal macrophages experiments of mice indicated that the fdTML extraction enhanced observably carbon expurgatory index, phagocytic rate and phagocytic index. The fdTML extraction could stimulate response of delayed hypersensitivity. The proliferation of ConA-induced mitogenic reponse for spleen lymphocyte was also increased. The amount of hemolytic antibody in mice serum increased compared with those of the control group mice. The half of hemolysis values in serum of treated mice increased compared to the control group. Furthermore, serum NO content in all treatment groups was higher than that of the control group whereas acid phosphatase and alkaline phosphatase activity was only significantly higher relative to the control group. Our findings suggest that supercritical CO2 fluid the fdTML extraction has potential as a health food supplement.

  15. Experimental research on durability of recycled aggregate concrete under freeze- thaw cycles

    Science.gov (United States)

    Cheng, Yanqiu; Shang, Xiaoyu; Zhang, Youjia

    2017-07-01

    The freeze-thaw durability of recycled aggregate concrete has significance for the concrete buildings in the cold region. In this paper, the rapid freezing and thawing cycles experience on recycle aggregate concrete was conducted to study on the effects of recycle aggregate amount, water-binder ratio and fly ash on freeze-thaw durability of recycle aggregate concrete. The results indicates that recycle aggregate amount makes the significant influence on the freeze-thaw durability. With the increase of recycled aggregates amount, the freeze-thaw resistance for recycled aggregate concrete decreases. Recycled aggregate concrete with lower water cement ratio demonstrates better performance of freeze-thaw durability. It is advised that the amount of fly ash is less than 30% for admixture of recycled aggregates in the cold region.

  16. Recent developments in novel freezing and thawing technologies applied to foods.

    Science.gov (United States)

    Wu, Xiao-Fei; Zhang, Min; Adhikari, Benu; Sun, Jincai

    2017-11-22

    This article reviews the recent developments in novel freezing and thawing technologies applied to foods. These novel technologies improve the quality of frozen and thawed foods and are energy efficient. The novel technologies applied to freezing include pulsed electric field pre-treatment, ultra-low temperature, ultra-rapid freezing, ultra-high pressure and ultrasound. The novel technologies applied to thawing include ultra-high pressure, ultrasound, high voltage electrostatic field (HVEF), and radio frequency. Ultra-low temperature and ultra-rapid freezing promote the formation and uniform distribution of small ice crystals throughout frozen foods. Ultra-high pressure and ultrasound assisted freezing are non-thermal methods and shorten the freezing time and improve product quality. Ultra-high pressure and HVEF thawing generate high heat transfer rates and accelerate the thawing process. Ultrasound and radio frequency thawing can facilitate thawing process by volumetrically generating heat within frozen foods. It is anticipated that these novel technologies will be increasingly used in food industries in the future.

  17. Effect of freezing temperature on the color of frozen salmon.

    Science.gov (United States)

    Ottestad, Silje; Enersen, Grethe; Wold, Jens Petter

    2011-09-01

    New freezing methods developed with the purpose of improved product quality after thawing can sometimes be difficult to get accepted in the market. The reason for this is the formation of ice crystals that can give the product a temporary color loss and make it less appealing. We have here used microscopy to study ice crystal size as a function of freezing temperature by investigating the voids in the cell tissue left by the ice crystals. We have also investigated how freezing temperature affects the color and the visible absorption spectra of frozen salmon. Freezing temperatures previously determined to be the best for quality after thawing (-40 to -60 °C) were found to cause a substantial loss in perceived color intensity during frozen state. This illustrated the conflict between optimal freezing temperatures with respect to quality after thawing against visual appearance during frozen state. Low freezing temperatures gave many small ice crystals, increased light scattering and an increased absorption level for all wavelengths in the visible region. Increased astaxanthin concentration on the other hand would give higher absorption at 490 nm. The results showed a clear potential of using visible interactance spectroscopy to differentiate between poor product coloration due to lack of pigmentation and temporary color loss due to light scattering by ice crystal. This type of measurements could be a useful tool in the development of new freezing methods and to monitor ice crystal growth during frozen storage. It could also potentially be used by the industry to prove good product quality. In this article we have shown that freezing food products at intermediate to low temperatures (-40 to -80 °C) can result in paler color during frozen state, which could affect consumer acceptance. We have also presented a spectroscopic method that can separate between poor product color and temporary color loss due to freezing. © 2011 Institute of Food Technologists®

  18. Does Platelet-Rich Plasma Freeze-Thawing Influence Growth Factor Release and Their Effects on Chondrocytes and Synoviocytes?

    Directory of Open Access Journals (Sweden)

    Alice Roffi

    2014-01-01

    Full Text Available PRP cryopreservation remains a controversial point. Our purpose was to investigate the effect of freezing/thawing on PRP molecule release, and its effects on the metabolism of chondrocytes and synoviocytes. PRP was prepared from 10 volunteers, and a half volume underwent one freezing/thawing cycle. IL-1β, HGF, PDGF AB/BB, TGF-β1, and VEGF were assayed 1 hour and 7 days after activation. Culture media of chondrocytes and synoviocytes were supplemented with fresh or frozen PRP, and, at 7 days, proliferation, gene expression, and secreted proteins levels were evaluated. Results showed that in the freeze-thawed PRP the immediate and delayed molecule releases were similar or slightly lower than those in fresh PRP. TGF-β1 and PDGF AB/BB concentrations were significantly reduced after freezing both at 1 hour and at 7 days, whereas HGF concentration was significantly lower in frozen PRP at 7 days. In fresh PRP IL-1β and HGF concentrations underwent a significant further increase after 7 days. Similar gene expression was found in chondrocytes cultured with both PRPs, whereas in synoviocytes HGF gene expression was higher in frozen PRP. PRP cryopreservation is a safe procedure, which sufficiently preserves PRP quality and its ability to induce proliferation and the production of ECM components in chondrocytes and synoviocytes.

  19. Does anxiety cause freezing of gait in Parkinson's disease?

    Directory of Open Access Journals (Sweden)

    Kaylena A Ehgoetz Martens

    Full Text Available Individuals with Parkinson's disease (PD commonly experience freezing of gait under time constraints, in narrow spaces, and in the dark. One commonality between these different situations is that they may all provoke anxiety, yet anxiety has never been directly examined as a cause of FOG. In this study, virtual reality was used to induce anxiety and evaluate whether it directly causes FOG. Fourteen patients with PD and freezing of gait (Freezers and 17 PD without freezing of gait (Non-Freezers were instructed to walk in two virtual environments: (i across a plank that was located on the ground (LOW, (ii across a plank above a deep pit (HIGH. Multiple synchronized motion capture cameras updated participants' movement through the virtual environment in real-time, while their gait was recorded. Anxiety levels were evaluated after each trial using self-assessment manikins. Freezers performed the experiment on two separate occasions (in their ON and OFF state. Freezers reported higher levels of anxiety compared to Non-Freezers (p < 0.001 and all patients reported greater levels of anxiety when walking across the HIGH plank compared to the LOW (p < 0.001. Freezers experienced significantly more freezing of gait episodes (p = 0.013 and spent a significantly greater percentage of each trial frozen (p = 0.005 when crossing the HIGH plank. This finding was even more pronounced when comparing Freezers in their OFF state. Freezers also had greater step length variability in the HIGH compared to the LOW condition, while the step length variability in Non-Freezers did not change. In conclusion, this was the first study to directly compare freezing of gait in anxious and non-anxious situations. These results present strong evidence that anxiety is an important mechanism underlying freezing of gait and supports the notion that the limbic system may have a profound contribution to freezing in PD.

  20. Freeze-drying wet digital prints: An option for salvage?

    International Nuclear Information System (INIS)

    Juergens, M C; Schempp, N

    2010-01-01

    On the occasion of the collapse of the Historical Archive of the City of Cologne in March 2009 and the ensuing salvage effort, questions were raised about the use of freeze-drying for soaked digital prints, a technique that has not yet been evaluated for these materials. This study examines the effects of immersion, air-drying, drying in a blotter stack, freezing and freeze-drying on 35 samples of major digital printing processes. The samples were examined visually before, during and after testing; evaluation of the results was qualitative. Results show that some prints were already damaged by immersion alone (e.g. bleeding inks and soluble coatings) to the extent that the subsequent choice of drying method made no significant difference any more. For those samples that did survive immersion, air-drying proved to be crucial for water-sensitive prints, since any contact with the wet surface caused serious damage. Less water-sensitive prints showed no damage throughout the entire procedure, regardless of drying method. Some prints on coated media suffered from minor surface disruption up to total delamination of the surface coating due to the formation of ice crystals during shock-freezing. With few exceptions, freeze-drying did not cause additional damage to any of the prints that hadn't already been damaged by freezing. It became clear that an understanding of the process and materials is important for choosing an appropriate drying method.

  1. Intact preservation of environmental samples by freezing under an alternating magnetic field.

    Science.gov (United States)

    Morono, Yuki; Terada, Takeshi; Yamamoto, Yuhji; Xiao, Nan; Hirose, Takehiro; Sugeno, Masaya; Ohwada, Norio; Inagaki, Fumio

    2015-04-01

    The study of environmental samples requires a preservation system that stabilizes the sample structure, including cells and biomolecules. To address this fundamental issue, we tested the cell alive system (CAS)-freezing technique for subseafloor sediment core samples. In the CAS-freezing technique, an alternating magnetic field is applied during the freezing process to produce vibration of water molecules and achieve a stable, super-cooled liquid phase. Upon further cooling, the temperature decreases further, achieving a uniform freezing of sample with minimal ice crystal formation. In this study, samples were preserved using the CAS and conventional freezing techniques at 4, -20, -80 and -196 (liquid nitrogen) °C. After 6 months of storage, microbial cell counts by conventional freezing significantly decreased (down to 10.7% of initial), whereas that by CAS-freezing resulted in minimal. When Escherichia coli cells were tested under the same freezing conditions and storage for 2.5 months, CAS-frozen E. coli cells showed higher viability than the other conditions. In addition, an alternating magnetic field does not impact on the direction of remanent magnetization in sediment core samples, although slight partial demagnetization in intensity due to freezing was observed. Consequently, our data indicate that the CAS technique is highly useful for the preservation of environmental samples. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  2. Heat transfer coefficient of cryotop during freezing.

    Science.gov (United States)

    Li, W J; Zhou, X L; Wang, H S; Liu, B L; Dai, J J

    2013-01-01

    Cryotop is an efficient vitrification method for cryopreservation of oocytes. It has been widely used owing to its simple operation and high freezing rate. Recently, the heat transfer performance of cryotop was studied by numerical simulation in several studies. However, the range of heat transfer coefficient in the simulation is uncertain. In this study, the heat transfer coefficient for cryotop during freezing process was analyzed. The cooling rates of 40 percent ethylene glycol (EG) droplet in cryotop during freezing were measured by ultra-fast measurement system and calculated by numerical simulation at different value of heat transfer coefficient. Compared with the results obtained by two methods, the range of the heat transfer coefficient necessary for the numerical simulation of cryotop was determined, which is between 9000 W/(m(2)·K) and 10000 W/(m (2)·K).

  3. Optoacoustic laser monitoring of cooling and freezing of tissues

    International Nuclear Information System (INIS)

    Larin, Kirill V; Larina, I V; Motamedi, M; Esenaliev, R O

    2002-01-01

    Real-time monitoring of cooling and freezing of tissues, cells, and other biological objects with a high spatial and time resolution, which is necessary for selective destruction of cancer and benign tumours during cryotherapy, as well as for preventing any damage to the structure and functioning of biological objects in cryobiology, is considered. The optoacoustic method, based on the measurement and analysis of acoustic waves induced by short laser pulses, is proposed for monitoring the cooling and freezing of the tissue. The effect of cooling and freezing on the amplitude and time profile of acoustic signals generated in real tissues and in a model object is studied. The experimental results indicate that the optoacoustic laser technique can be used for real-time monitoring of cooling and freezing of biological objects with a submillimeter spatial resolution and a high contrast. (laser biology and medicine)

  4. Exploring high-density baryonic matter: Maximum freeze-out density

    Energy Technology Data Exchange (ETDEWEB)

    Randrup, Joergen [Lawrence Berkeley National Laboratory, Nuclear Science Division, Berkeley, CA (United States); Cleymans, Jean [University of Cape Town, UCT-CERN Research Centre and Department of Physics, Rondebosch (South Africa)

    2016-08-15

    The hadronic freeze-out line is calculated in terms of the net baryon density and the energy density instead of the usual T and μ{sub B}. This analysis makes it apparent that the freeze-out density exhibits a maximum as the collision energy is varied. This maximum freeze-out density has μ{sub B} = 400 - 500 MeV, which is above the critical value, and it is reached for a fixed-target bombarding energy of 20-30 GeV/N well within the parameters of the proposed NICA collider facility. (orig.)

  5. Freeze-thaw performance testing of whole concrete railroad ties.

    Science.gov (United States)

    2013-10-01

    Freezing and thawing durability tests of prestressed concrete ties are normally performed according to ASTM C666 specifications. Small specimens are cut from the shoulders of concrete ties and tested through 300 cycles of freezing and thawing. Saw-cu...

  6. Positron probe to study the freezing of nanodroplets

    International Nuclear Information System (INIS)

    Pujari, P.K.

    2010-01-01

    Positron is an excellent in situ probe to study the phase behavior of fluid confined in nanodomains. The study of phase behavior (freezing/melting) of nano confined fluid or nanodroplet has great relevance in fundamental research as well as applications in nano-tribology, nanofabrication, membrane separation, interfacial adhesion and lubrication. It is seen that the properties of freezing/melting of nanodroplets are different from their bulk behavior due to the combined effects of finite size, surface force, surface anisotropy, pore disorder and reduced dimensionality. We have used positron annihilation spectroscopy (PAS) to study the freezing/melting behavior of different organic liquids like benzene, ethylene glycol and isopropanol confined in nanopores of ZSM5 zeolite and silica gel

  7. Mechanism study of freeze-valve for molten salt reactor (MSR)

    International Nuclear Information System (INIS)

    Qinhua, Zhang

    2014-01-01

    Molten salt reactor (MSR) is one of the fourth generation nuclear reactor, ordinary nuclear grade valve is unsuitable for MSR due to its special coolant and extraordinary working temperature. Freeze-valve is proposed as the most appropriate valve for MSR, but the technology issue about freeze-valve has not been report in recent decades. Its significance to test the comprehensive property of freeze-valve for the application in MSR. A high temperature molten salt test loop was built which the physics property of salt is similar to the coolant of MSR. The results indicate that freeze-valve has a good performance use in the molten salt circumstances of high temperature (max 700 deg. C) and strong corrosion (authors)

  8. Non-identical particle femtoscopy in models with single freeze-out

    International Nuclear Information System (INIS)

    Kisiel, Adam

    2007-01-01

    We present femtoscopic results from hydrodynamics-inspired thermal models with single freeze-out. Non-identical particle femtoscopy is studied and compared to results of identical particle correlations. Special emphasis is put on shifts between average space-time emission points of non-identical particles of different masses. They are found to be sensitive to both the spatial shift coming from radial flow, as well as average emission time difference coming from the resonance decays. The Terminator Monte-Carlo program was chosen for this study because it realistically models both of these effects. In order to analyze the results we present and test the methodology of non-identical particle correlations. (author)

  9. Post Thawing Sperm Quality and Ca+2 Intensity Characters of Local Goat Sperm After Freezing by Simple Method Using Deep Freezing

    Directory of Open Access Journals (Sweden)

    Gatot Ciptadi

    2018-02-01

    Full Text Available The objective of this research was to determine the effect of the simple modified freezing method, 1°C/minute freezing rate with different diluter ration on a post-thawing quality of local goat sperm namely Peranakan Etawah (PE. This work is aimed to study the quality of post-thawing sperm and to characterize the calcium intensity profile of both fresh and post thawing goat sperm. The method used is the experimental design of a laboratory. Freezing semen was performed in 2 main temperatures of -45°C then -196°C respectively using Mr. Frosty (® System. Early Sperm characters of Ca+2 intensity was performed by Confocal Laser Scanning Microscope (CLSM through Fluo-3 staining and Ca++ intensity was analysis descriptively. The result showed that post-thawing qualities are considered as good as standard qualities, at least, more than 40% based on Indonesian National Standard (SNI, 2014. The different level diluents commercial of Andromeda used were influenced highly significant (P<0.01. The best diluents ration is 1:4 (v/v for final sperms stocked at -196°C. However freezing sperm conserved in -196°C is better than in -45°C. Meanwhile, the sperm characters of two condition showed the important variation of Ca+2 intensity, with the length of region measurement of 39.06±4.595 and 32.696±9.011 µm each.  It was concluded that the calcium intensity pattern was varied more and higher in fresh sperm than in freezing sperms. This simple modified method of a freezing system was considered as a feasible alternative method for goat semen in a reason for both for sperm post-thawing quality and practical purposes.

  10. Emerging techniques for assisting and accelerating food freezing processes: A review of recent research progresses.

    Science.gov (United States)

    Cheng, Lina; Sun, Da-Wen; Zhu, Zhiwei; Zhang, Zi

    2017-03-04

    Freezing plays an important role in food preservation and the emergence of rapid freezing technologies can be highly beneficial to the food industry. This paper reviews some novel food freezing technologies, including high-pressure freezing (HPF), ultrasound-assisted freezing (UAF), electrically disturbed freezing (EF) and magnetically disturbed freezing (MF), microwave-assisted freezing (MWF), and osmo-dehydro-freezing (ODF). HPF and UAF can initiate ice nucleation rapidly, leading to uniform distribution of ice crystals and the control of their size and shape. Specifically, the former is focused on increasing the degree of supercooling, whereas the latter aims to decrease it. Direct current electric freezing (DC-EF) and alternating current electric freezing (AC-EF) exhibit different effects on ice nucleation. DC-EF can promote ice nucleation and AC-EF has the opposite effect. Furthermore, ODF has been successfully used for freezing various vegetables and fruit. MWF cannot control the nucleation temperature, but can decrease supercooling degree, thus decreasing the size of ice crystals. The heat and mass transfer processes during ODF have been investigated experimentally and modeled mathematically. More studies should be carried out to understand the effects of these technologies on food freezing process.

  11. Shrinkage of spray-freeze-dried microparticles of pure protein for ballistic injection by manipulation of freeze-drying cycle.

    Science.gov (United States)

    Straller, Georg; Lee, Geoffrey

    2017-10-30

    Spray-freeze-drying was used to produce shrivelled, partially-collapsed microparticles of pure proteins that may be suitable for use in a ballistic injector. Various modifications of the freeze drying cycle were examined for their effects on collapse of the pure protein microparticles. The use of annealing at a shelf temperature of up to +10°C resulted in no visible particle shrinkage. This was because of the high T g ' of the pure protein. Inclusion of trehalose or sucrose led to particle shrinkage because of the plasticizing effects of the disaccharides on the protein. Only by extending the duration of primary drying from 240 to 2745min at shelf temperatures in the range -12 to -8°C were shrivelled, wrinkled particles of bSA and bCA of reduced porosity obtained. Manipulation of the freeze-drying cycle used for SFD can therefore be used to modify particle morphology and increase particle density. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Immunogenicity and safety of a novel MMR vaccine (live, freeze-dried) containing the Edmonston-Zagreb measles strain, the Hoshino mumps strain, and the RA 27/3 rubella strain: Results of a randomized, comparative, active controlled phase III clinical trial.

    Science.gov (United States)

    Sood, Ashwani; Mitra, Monjori; Joshi, Himanshu Arvind; Nayak, Uma Siddhartha; Siddaiah, Prashanth; Babu, T Ramesh; Mahapatro, Samarendra; Sanmukhani, Jayesh; Gupta, Gaurav; Mittal, Ravindra; Glueck, Reinhard

    2017-07-03

    This phase III clinical trial was conducted to evaluate the immunogenicity and safety of the single-dose and multi-dose formulations of a novel MMR vaccine (live, freeze-dried) developed by M/s Cadila Healthcare Limited, India (Cadila MMR vaccine), containing the Hoshino mumps strain, compared to that of an existing MMR vaccine (live, freeze-dried) developed by M/s Serum Institute of India Limited, India (Serum MMR vaccine). These two vaccines have similar measles and rubella strains, but different mumps strains (Hoshino in Cadila MMR vaccine, and L-Zagreb in Serum MMR vaccine). Three hundred and twenty-eight subjects of either sex, aged 15-18 months, were randomized in a 2:1 ratio to receive either the Cadila or Serum MMR vaccine. Immunogenicity assessments (IgG antibodies against measles, mumps, and rubella viruses) were done at baseline and 42 d after vaccination. Solicited (local and systemic) and unsolicited adverse events were recorded for up to 42 d following vaccination. The Cadila MMR vaccine was found to be non-inferior to the Serum MMR vaccine in terms of end-of-study proportion of subjects seropositive for anti-measles antibodies (100.0% in both groups), anti-mumps antibodies (94.5% vs. 94.0%), and anti-rubella antibodies (95.5% vs. 91.0%). Both vaccines were well tolerated by all study participants; the most common adverse event reported in both groups was fever, followed by rash. The results of this phase III clinical trial show that the novel Cadila MMR vaccine is non-inferior to the Serum MMR vaccine.

  13. Freeze-Thaw Cycles and Soil Biogeochemistry: Implications for Greenhouse Gas emission

    Science.gov (United States)

    Rezanezhad, F.; Milojevic, T.; Oh, D. H.; Parsons, C. T.; Smeaton, C. M.; Van Cappellen, P.

    2016-12-01

    Freeze-thaw cycles represent a major natural climate forcing acting on soils at middle and high latitudes. Repeated freezing and thawing of soils changes their physical properties, geochemistry, and microbial community structure, which together govern the biogeochemical cycling of carbon and nutrients. In this presentation, we focus on how freeze-thaw cycles regulate carbon and nitrogen cycling and how these transformations influence greenhouse gas (GHG) fluxes. We present a novel approach, which combines the acquisition of physical and chemical data in a newly developed experimental soil column system. This system simulates realistic soil temperature profiles during freeze-thaw cycles. A high-resolution, Multi-Fiber Optode (MuFO) microsensor technique was used to detect oxygen (O2) continuously in the column at multiple depths. Surface and subsurface changes to gas and aqueous phase chemistry were measured to delineate the pathways and quantify soil respiration rates during freeze-thaw cycles. The results indicate that the time-dependent release of GHG from the soil surface is influenced by a combination of two key factors. Firstly, fluctuations in temperature and O2 availability affect soil biogeochemical activity and GHG production. Secondly, the recurrent development of a physical ice barrier prevents exchange of gaseous compounds between the soil and atmosphere during freezing conditions; removal of this barrier during thaw conditions increases GHG fluxes. During freezing, O2 levels in the unsaturated zone decreased due to restricted gas exchange with the atmosphere. As the soil thawed, O2 penetrated deeper into the soil enhancing the aerobic mineralization of organic carbon and nitrogen. Additionally, with the onset of thawing a pulse of gas flux occurred, which is attributed to the build-up of respiratory gases in the pore space during freezing. The latter implies enhanced anaerobic respiration as O2 supply ceases when the upper soil layer freezes.

  14. Alcohol Brine Freezing of Japanese Horse Mackerel (Trachurus japonicus) for Raw Consumption

    Science.gov (United States)

    Maeda, Toshimichi; Yuki, Atsuhiko; Sakurai, Hiroshi; Watanabe, Koichiro; Itoh, Nobuo; Inui, Etsuro; Seike, Kazunori; Mizukami, Yoichi; Fukuda, Yutaka; Harada, Kazuki

    In order to test the possible application of alcohol brine freezing to Japanese horse mackerel (Trachurus japonicus) for raw consumption, the quality and taste of fish frozen by direct immersion in 60% ethanol brine at -20, -25 and -30°C was compared with those by air freezing and fresh fish without freezing. Cracks were not found during the freezing. Smell of ethanol did not remain. K value, an indicator of freshness, of fish frozen in alcohol brine was less than 8.3%, which was at the same level as those by air freezing and fresh fish. Oxidation of lipid was at the same level as air freezing does, and lower than that of fresh fish. The pH of fish frozen in alcohol brine at -25 and -30°C was 6.5 and 6.6, respectively, which were higher than that by air freezing and that of fresh fish. Fish frozen in alcohol brine was better than that by air and at the same level as fresh fish in total evaluation of sensory tests. These results show that the alcohol brine freezing is superior to air freezing, and fish frozen in alcohol brine can be a material for raw consumption. The methods of thawing in tap water, cold water, refrigerator, and at room temperature were compared. Thawing in tap water is considered to be convenient due to the short thaw time and the quality of thawed fish that was best among the methods.

  15. HPLC separation of human serum albumin isoforms based on their isoelectric points

    Science.gov (United States)

    Bonilla, Lucía; Torres, María José; Schopfer, Francisco; Freeman, Bruce A.; Armas, Larissa; Ricciardi, Alejandro; Alvarez, Beatriz; Radi, Rafael

    2014-01-01

    Human serum albumin (HSA) is the most abundant protein in plasma. Cys34, the only free Cys residue, is the predominant plasma thiol and a relevant sacrificial antioxidant. Both in vivo circulating HSA and pharmaceutical preparations are heterogeneous with respect to the oxidation state of Cys34. In this work, we developed an external pH gradient chromatofocusing procedure that allows the analysis of the oxidation status of HSA in human plasma and biopharmaceutical products based on the different apparent isoelectric points and chemical properties of the redox isoforms. Specifically, reduced-mercury blocked HSA (HSA–SHg+), HSA with Cys34 oxidized to sulfenic acid (HSA–SOH) and HSA oxidized to sulfinate anion (HSA–SO2−) can be separated with resolutions of 1.4 and 3.1 (first and last pair) and hence quantified and purified. In addition, an N-terminally degraded isoform (HSA3–585) in different redox states can be resolved as well. Confirmation of the identity of the chromatofocusing isolated isoforms was achieved by high resolution whole protein MS. It is proposed that the chromatofocusing procedure can be used to produce more exact and complete descriptions of the redox status of HSA in vivo and in vitro. Finally, the scalability capabilities of the chromatofocusing procedure allow for the preparation of highly pure standards of several redox isoforms of HSA PMID:24316526

  16. Model for heat and mass transfer in freeze-drying of pellets.

    Science.gov (United States)

    Trelea, Ioan Cristian; Passot, Stéphanie; Marin, Michèle; Fonseca, Fernanda

    2009-07-01

    Lyophilizing frozen pellets, and especially spray freeze-drying, have been receiving growing interest. To design efficient and safe freeze-drying cycles, local temperature and moisture content in the product bed have to be known, but both are difficult to measure in the industry. Mathematical modeling of heat and mass transfer helps to determine local freeze-drying conditions and predict effects of operation policy, and equipment and recipe changes on drying time and product quality. Representative pellets situated at different positions in the product slab were considered. One-dimensional transfer in the slab and radial transfer in the pellets were assumed. Coupled heat and vapor transfer equations between the temperature-controlled shelf, the product bulk, the sublimation front inside the pellets, and the chamber were established and solved numerically. The model was validated based on bulk temperature measurement performed at two different locations in the product slab and on partial vapor pressure measurement in the freeze-drying chamber. Fair agreement between measured and calculated values was found. In contrast, a previously developed model for compact product layer was found inadequate in describing freeze-drying of pellets. The developed model represents a good starting basis for studying freeze-drying of pellets. It has to be further improved and validated for a variety of product types and freeze-drying conditions (shelf temperature, total chamber pressure, pellet size, slab thickness, etc.). It could be used to develop freeze-drying cycles based on product quality criteria such as local moisture content and glass transition temperature.

  17. Effect of Repeated Freeze-Thaw Cycles on Beef Quality and Safety

    Science.gov (United States)

    Rahman, Mohammad Hafizur; Hossain, Mohammad Mujaffar; Rahman, Syed Mohammad Ehsanur; Hashem, Mohammad Abul

    2014-01-01

    The objectives of this study were to know the effect of repeated freeze-thaw cycles of beef on the sensory, physicochemical quality and microbiological assessment. The effects of three successive freeze-thaw cycles on beef forelimb were investigated comparing with unfrozen fresh beef for 75 d by keeping at −20±1℃. The freeze-thaw cycles were subjected to three thawing methods and carried out to know the best one. As the number of freeze-thaw cycles increased color and odor declined significantly before cook within the cycles and tenderness, overall acceptability also declined among the cycles after cook by thawing methods. The thawing loss increased and dripping loss decreased significantly (pcycles and then decreased. Cooking loss increased in cycle 1 and 3, but decreased in cycle 2. pH decreased significantly (pcycles. Moreover, drip loss, cooking loss and WHC were affected (pcycles. 2-Thiobarbituric acid (TBARS) value increased (pcycles and among the cycles by thawing methods. Total viable bacteria, total coliform and total yeast-mould count decreased significantly (pcycles in comparison to the initial count in repeated freeze-thaw cycles. As a result, repeated freeze-thaw cycles affected the sensory, physicochemical and microbiological qua- lity of beef, causing the deterioration of beef quality, but improved the microbiological quality. Although repeated freeze-thaw cycles did not affect much on beef quality and safety but it may be concluded that repeated freeze and thaw should be minimized in terms of beef color for commercial value and WHC and tenderness/juiciness for eating quality. PMID:26761286

  18. Serum biotin in Japanese children: Enzyme-linked immunosorbent assay measurement.

    Science.gov (United States)

    Wakabayashi, Kenji; Kodama, Hiroko; Ogawa, Eishin; Sato, Yasuhiro; Motoyama, Kahoko; Suzuki, Mitsuyoshi

    2016-09-01

    Biotin deficiency has been reported in Japanese infants fed special formulas for medical reasons, including those with milk allergy and congenital metabolic diseases, because these formulas contain little biotin. Serum biotin measurement is useful for diagnosing biotin deficiency. We applied a simple and rapid method to analyze serum biotin, and established normal ranges for children and adults. Serum biotin in 188 healthy Japanese children aged 0-4 years and in 25 healthy adults was analyzed using a Biotin ELISA Kit (immundiagnostik). The effects of various conditions on the measurement of serum biotin were also examined. Median biotin in children aged 0-4 years was 10.4 ng/dL (IQR, 7.9-13.4 ng/dL), and that in adults was 12.9 ng/dL (IQR, 10.8-15.8 ng/dL). Normal range was 4.7-22.0 ng/dL in children and 8.4-20.5 ng/dL in adults (calculated using two-sided 95%CI). Measurements obtained with this method were not affected by frozen storage, freeze-thaw, or hemolysis, indicating that serum biotin can be analyzed accurately under these conditions, with a possible application to plasma samples. Serum biotin was significantly lower in children than in adults, with the normal range being 4.7-22.0 ng/dL in children and 8.4-20.5 ng/dL in adults. This simple and accurate enzyme-linked immunosorbent assay method is useful for diagnosing biotin deficiency. © 2016 The Authors. Pediatrics International published by John Wiley & Sons Australia, Ltd on behalf of Japan Pediatric Society.

  19. Analytical solution and numerical simulation of the liquid nitrogen freezing-temperature field of a single pipe

    Science.gov (United States)

    Cai, Haibing; Xu, Liuxun; Yang, Yugui; Li, Longqi

    2018-05-01

    Artificial liquid nitrogen freezing technology is widely used in urban underground engineering due to its technical advantages, such as simple freezing system, high freezing speed, low freezing temperature, high strength of frozen soil, and absence of pollution. However, technical difficulties such as undefined range of liquid nitrogen freezing and thickness of frozen wall gradually emerge during the application process. Thus, the analytical solution of the freezing-temperature field of a single pipe is established considering the freezing temperature of soil and the constant temperature of freezing pipe wall. This solution is then applied in a liquid nitrogen freezing project. Calculation results show that the radius of freezing front of liquid nitrogen is proportional to the square root of freezing time. The radius of the freezing front also decreases with decreased the freezing temperature, and the temperature gradient of soil decreases with increased distance from the freezing pipe. The radius of cooling zone in the unfrozen area is approximately four times the radius of the freezing front. Meanwhile, the numerical simulation of the liquid nitrogen freezing-temperature field of a single pipe is conducted using the Abaqus finite-element program. Results show that the numerical simulation of soil temperature distribution law well agrees with the analytical solution, further verifies the reliability of the established analytical solution of the liquid nitrogen freezing-temperature field of a single pipe.

  20. Thermodynamical effects accompanied freezing of two water layers separated by sea ice sheet

    Science.gov (United States)

    Bogorodsky, Petr; Marchenko, Aleksey

    2014-05-01

    The process of melt pond freezing is very important for generation of sea ice cover thermodynamic and mass balance during winterperiod. However, due to significant difficulties of field measurements the available data of model estimations still have no instrumental confirmation. In May 2009 the authors carried out laboratory experiment on freezing of limited water volume in the University Centre in Svalbard ice tank. In the course of experiment fresh water layer of 27.5 cm thickness at freezing point poured on the 24 cm sea ice layer was cooled during 50 hours at the temperature -10º C and then once again during 60 hours at -20º C. For revealing process typical characteristics the data of continuous measurements of temperature and salinity in different phases were compared with data of numerical computations obtained with thermodynamic model which was formulated in the frames of 1-D equation system (infinite extension of water freezing layer) and adapted to laboratory conditions. The known surprise of the experiment became proximity of calculated and measured estimates of process dynamics that confirmed the adequacy of the problem mathematical statement (excluding probably process finale stage). This effect can be explained by formation of cracks on the upper layer of ice at sharp decreases of air temperature, which temporary compensated hydrostatic pressure growth during freezing of closed water volume. Another compensated mechanism can be migration of brine through the lower layer of ice under influence of vertical pressure gradient and also rejection of gas dissolved in water which increased its compressibility. During 110 hours cooling thickness of water layer between ice layers reduced approximately to 2 cm. According to computations this layer is not chilled completely but keeps as thin brine interlayer within ice body whose thickness (about units of mm) is determined by temperature fluctuations of cooled surface. Nevertheless, despite good coincidence of

  1. Folic acid content in thermostabilized and freeze-dried space shuttle foods

    Science.gov (United States)

    Lane, H. W.; Nillen, J. L.; Kloeris, V. L.

    1995-01-01

    This study was designed to determine whether freeze-dried and thermostabilized foods on a space shuttle contain adequate folate and to investigate any effects of freeze-drying on folacin. Frozen vegetables were analyzed after three states of processing: thawed; cooked; and rehydrated. Thermostabilized items were analyzed as supplied with no further processing. Measurable folate decreased in some freeze-dried vegetables and increased in others. Folacin content of thermostabilized food items was comparable with published values. We concluded that although the folacin content of some freeze-dried foods was low, adequate folate is available from the shuttle menu to meet RDA guidelines.

  2. Does Anxiety Cause Freezing of Gait in Parkinson's Disease?

    Science.gov (United States)

    Ehgoetz Martens, Kaylena A.; Ellard, Colin G.; Almeida, Quincy J.

    2014-01-01

    Individuals with Parkinson's disease (PD) commonly experience freezing of gait under time constraints, in narrow spaces, and in the dark. One commonality between these different situations is that they may all provoke anxiety, yet anxiety has never been directly examined as a cause of FOG. In this study, virtual reality was used to induce anxiety and evaluate whether it directly causes FOG. Fourteen patients with PD and freezing of gait (Freezers) and 17 PD without freezing of gait (Non-Freezers) were instructed to walk in two virtual environments: (i) across a plank that was located on the ground (LOW), (ii) across a plank above a deep pit (HIGH). Multiple synchronized motion capture cameras updated participants' movement through the virtual environment in real-time, while their gait was recorded. Anxiety levels were evaluated after each trial using self-assessment manikins. Freezers performed the experiment on two separate occasions (in their ON and OFF state). Freezers reported higher levels of anxiety compared to Non-Freezers (panxiety when walking across the HIGH plank compared to the LOW (panxiety is an important mechanism underlying freezing of gait and supports the notion that the limbic system may have a profound contribution to freezing in PD. PMID:25250691

  3. Freeze-fracture of infected plant leaves in ethanol for scanning electron microscopic study of fungal pathogens.

    Science.gov (United States)

    Moore, Jayma A; Payne, Scott A

    2012-01-01

    Fungi often are found within plant tissues where they cannot be visualized with the scanning electron microscope (SEM). We present a simple way to reveal cell interiors while avoiding many common causes of artifact. Freeze-fracture of leaf tissue using liquid nitrogen during the 100% ethanol step of the dehydration process just before critical point drying is useful in exposing intracellular fungi to the SEM.

  4. Impact of nucleon mass shift on the freeze-out process

    International Nuclear Information System (INIS)

    Zschocke, Sven; Csernai, Laszlo Pal; Molnar, Etele; Nyiri, Agnes; Manninen, Jaakko

    2005-01-01

    The freeze-out of a massive nucleon gas through a finite layer with a timelike normal is studied. The impact of the in-medium nucleon mass shift on the freeze-out process is investigated. A considerable modification of the thermodynamic variables of temperature, flow velocity, energy density, and particle density has been found. Because of the nucleon mass shift the freeze-out particle distribution functions are changed noticeably in comparison with the evaluations, which use the vacuum nucleon mass

  5. The relationship between freezing point of milk and milk components and its changes during lactation in Czech Pied and Holstein cows

    Directory of Open Access Journals (Sweden)

    Gustav Chládek

    2005-01-01

    Full Text Available The freezing point of milk (FPM is an instant indicator of violated technological quality of raw milk, especially of dilution. FPM can also vary due to numerous effects associated with changes in milk composition and milk characteristics. Beside the effect of season, phase of lactation, breed, milk yield, sub-clinical mastitis etc. the impacts of nutrition and dietary or metabolic disorders are the most significant and the most frequent (GAJDŮŠEK, 2003. FPM is a relatively stable physical characteristic and due to osmotically active elements it ranges from – 0.510 to – 0.535 °C (HANUŠ et al., 2003b. Recently ŠUSTOVÁ (2001 studied the freezing point of milk in pool samples; she observed seasonal changes in FPM of mixed milk and the effect of different diets on FPM values. KOLOŠTA (2003 looked into the effect of grazing season on FPM. HANUŠ et al. (2003a analysed possible effects of handling of milk components on FPM.The aim of this work was to describe the relationship between FPM and milk components and the impact of breed, number and phase of lactation on FPM. We analysed 328 milk samples in total, out of which 137 samples were of Czech Pied cows and 191 samples of Holstein cows. The effect of number and phase of lactation was evaluated for both breeds together. The greatest coefficients of correlation in total were found between FPM and lactose content (r = 0.600 and solids non fat (r = 0.523. Lower coefficients of correlation were found between FPM and milk fat content (r = 0.235, milk protein content (r = 0.260 and urea concentration (r = 0.256. These coefficients were considerably lower in Holstein cows than in Czech Pied cows. The coefficients of correlation between FPM and number and phase of lactation and somatic cells count were insignificant. The total mean value of FPM was – 0.534 °C. Breed statistically significantly (P<0.01 affected FPM (+0.006 °C in C breed and milk fat content (+0.19 % in H

  6. Analyses of out-of-pile freezing experiments by SIMMER-II

    International Nuclear Information System (INIS)

    Sawada, Tetsuo; Ninokata, Hisashi

    1994-01-01

    This paper describes the interpretation of the TRAN Simulation experiments performed by SIMBATH facility of KfK. Two typical TRAN Simulation experiments were analyzed by using the SIMMER-II code. The original TRAN experiments were performed at SNL in order to examine the freezing behavior of molten UO 2 injected into an annular channel. In the TRAN Simulation experiments of SIMBATH series, similar freezing phenomena were investigated for molten thermite, i.e., a mixture of Al 2 O 3 and iron, instead of UO 2 . The analyses of the simulation experiments by SIMMER-II code aimed at clarifying the applicability of the code and interpreting the freezing process during the experiments. Distribution of molten materials that had deposited in the test section was compared between experimental measurements and calculation by SIMMER-II. Through this study, it has been confirmed that SIMMER-II can well reproduce the TRAN Simulation experiments with allowable difference. The calculations by SIMMER-II also suggested that further model improvements, e.g., freezing on a convex surface, would be effective for a better interpretation of the freezing phenomena. (author)

  7. Effect of freeze/thaw cycles on several biomarkers in urine from patients with kidney disease.

    Science.gov (United States)

    Zhang, Yinan; Luo, Yi; Lu, Huijuan; Wang, Niansong; Shen, Yixie; Chen, Ruihua; Fang, Pingyan; Yu, Hong; Wang, Congrong; Jia, Weiping

    2015-04-01

    Urine samples were collected from eleven randomly selected patients with kidney disease, including diabetic nephropathy, chronic nephritis, and nephritic syndrome. Urine samples were treated with one of four protocols for freezing and thawing: freeze directly and thaw directly; freeze directly and thaw by temperature gradient; freeze by temperature gradient and thaw directly; and freeze by temperature gradient and thaw by temperature gradient. After one to six freeze/thaw cycles at -20°C or -80°C, different biomarkers showed differential stabilities. The concentrations of total protein, calcium, and potassium did not change significantly after five freeze/thaw cycles at either -20°C or -80°C. Albumin could only sustain three freeze/thaw cycles at -20°C before it started to degrade. We recommend that urine be stored at -80°C as albumin and the organic ions could sustain five and six freeze/thaw cycles, respectively, using the simple "direct freeze and direct thaw" protocol. Furthermore, in most cases, gradient freeze/thaw cycles are not necessary for urine sample storage.

  8. Entree Production Guides for Cook/Freeze Systems

    Science.gov (United States)

    1983-03-01

    92.29 50.00 22,680 1. Fill roasting pans with cut-up chicken . Salt 0.35 0.19 86 2. Combine ingredients listed Pepper, black 0.07 0.04 18 in this...INSTALLATIONS FREEZING RECIPES HOSPITAL FEEDING i, WACT (Vmentbs m reves - W neete y lsmer ~lr y block nguber) Entree production guides have been...control and better use of personnel. Standard recipes must be adapted to production guides for use in cook/freeze systems. Products must withstand the

  9. Transcriptome Analysis of Spartina pectinata in Response to Freezing Stress.

    Directory of Open Access Journals (Sweden)

    Gyoungju Nah

    Full Text Available Prairie cordgrass (Spartina pectinata, a perennial C4 grass native to the North American prairie, has several distinctive characteristics that potentially make it a model crop for production in stressful environments. However, little is known about the transcriptome dynamics of prairie cordgrass despite its unique freezing stress tolerance. Therefore, the purpose of this work was to explore the transcriptome dynamics of prairie cordgrass in response to freezing stress at -5°C for 5 min and 30 min. We used a RNA-sequencing method to assemble the S. pectinata leaf transcriptome and performed gene-expression profiling of the transcripts under freezing treatment. Six differentially expressed gene (DEG groups were categorized from the profiling. In addition, two major consecutive orders of gene expression were observed in response to freezing; the first being the acute up-regulation of genes involved in plasma membrane modification, calcium-mediated signaling, proteasome-related proteins, and transcription regulators (e.g., MYB and WRKY. The follow-up and second response was of genes involved in encoding the putative anti-freezing protein and the previously known DNA and cell-damage-repair proteins. Moreover, we identified the genes involved in epigenetic regulation and circadian-clock expression. Our results indicate that freezing response in S. pectinata reflects dynamic changes in rapid-time duration, as well as in metabolic, transcriptional, post-translational, and epigenetic regulation.

  10. Quality Evaluation of Pork with Various Freezing and Thawing Methods

    Science.gov (United States)

    2014-01-01

    In this study, the physicochemical and sensory quality characteristics due to the influence of various thawing methods on electro-magnetic and air blast frozen pork were examined. The packaged pork samples, which were frozen by air blast freezing at −45℃ or electro-magnetic freezing at −55℃, were thawed using 4 different methods: refrigeration (4±1℃), room temperature (RT, 25℃), cold water (15℃), and microwave (2450 MHz). Analyses were carried out to determine the drip and cooking loss, water holding capacity (WHC), moisture content and sensory evaluation. Frozen pork thawed in a microwave indicated relatively less thawing loss (0.63-1.24%) than the other thawing methods (0.68-1.38%). The cooking loss after electro-magnetic freezing indicated 37.4% by microwave thawing, compared with 32.9% by refrigeration, 36.5% by RT, and 37.2% by cold water in ham. The thawing of samples frozen by electro-magnetic freezing showed no significant differences between the methods used, while the moisture content was higher in belly thawed by microwave (62.0%) after electro-magnetic freezing than refrigeration (54.8%), RT (61.3%), and cold water (61.1%). The highest overall acceptability was shown for microwave thawing after electro-magnetic freezing but there were no significant differences compared to that of the other samples. PMID:26761493

  11. Soft tissue freezing process. Identification of the dual-phase lag model parameters using the evolutionary algorithm

    Science.gov (United States)

    Mochnacki, Bohdan; Majchrzak, Ewa; Paruch, Marek

    2018-01-01

    In the paper the soft tissue freezing process is considered. The tissue sub-domain is subjected to the action of cylindrical cryoprobe. Thermal processes proceeding in the domain considered are described using the dual-phase lag equation (DPLE) supplemented by the appropriate boundary and initial conditions. DPLE results from the generalization of the Fourier law in which two lag times are introduced (relaxation and thermalization times). The aim of research is the identification of these parameters on the basis of measured cooling curves at the set of points selected from the tissue domain. To solve the problem the evolutionary algorithms are used. The paper contains the mathematical model of the tissue freezing process, the very short information concerning the numerical solution of the basic problem, the description of the inverse problem solution and the results of computations.

  12. Separation of Contaminants in The Freeze/Thaw Process

    Directory of Open Access Journals (Sweden)

    Szpaczyński Janusz A.

    2017-06-01

    Full Text Available These studies examined the concept of concentration and purification of several types of wastewater by freezing and thawing. The experiments demonstrated that freezing of contaminated liquid contributed to concentration of contaminants in solution as well as significant concentration and agglomeration of solid particles. A high degree of purification was achieved for many parameters. The results of comparative laboratory tests for single and multiple freezing are presented. It was found that there was a higher degree of concentration of pollutants in wastewater frozen as man-made snow than in bulk ice. Furthermore, the hypothesis that long storage time of liquid as snow and sufficient temperature gradient metamorphism allows for high efficiency of the concentration process was confirmed. It was reported that the first 30% of the melted liquid volume contained over 90% of all impurities. It gives great opportunities to use this method to concentrate pollutants. The results revealed that the application of this process in full scale is possible. Significant agglomeration of solid particles was also noted. Tests with clay slurry showed that repeated freezing and thawing processes significantly improve the characteristics of slurry for sedimentation and filtration.

  13. PHBV/PLLA-based composite scaffolds fabricated using an emulsion freezing/freeze-drying technique for bone tissue engineering: surface modification and in vitro biological evaluation

    International Nuclear Information System (INIS)

    Sultana, Naznin; Wang Min

    2012-01-01

    Tissue engineering combines living cells with biodegradable materials and/or bioactive components. Composite scaffolds containing biodegradable polymers and nanosized osteoconductive bioceramic with suitable properties are promising for bone tissue regeneration. In this paper, based on blending two biodegradable and biocompatible polymers, namely poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and poly(l-lactic acid) (PLLA) with incorporated nano hydroxyapatite (HA), three-dimensional composite scaffolds with controlled microstructures and an interconnected porous structure, together with high porosity, were fabricated using an emulsion freezing/freeze-drying technique. The influence of various parameters involved in the emulsion freezing/freeze-drying technique was studied for the fabrication of good-quality polymer scaffolds based on PHBV polymers. The morphology, mechanical properties and crystallinity of PHBV/PLLA and HA in PHBV/PLLA composite scaffolds and PHBV polymer scaffolds were studied. The scaffolds were coated with collagen in order to improve wettability. During in vitro biological evaluation study, it was observed that SaOS-2 cells had high attachment on collagen-coated scaffolds. Significant improvement in cell proliferation and alkaline phosphatase activity for HA-incorporated composite scaffolds was observed due to the incorporation of HA. After 3 and 7 days of culture on all scaffolds, SaOS-2 cells also had normal morphology and growth. These results indicated that PHBV/PLLA-based scaffolds fabricated via an emulsion freezing/freeze-drying technique were favorable sites for osteoblastic cells and are promising for the applications of bone tissue engineering.

  14. Accelerated redox reaction between chromate and phenolic pollutants during freezing

    Energy Technology Data Exchange (ETDEWEB)

    Ju, Jinjung; Kim, Jaesung [Department of Environmental Sciences and Biotechnology, Hallym University, Chuncheon, Gangwon-do 24252 (Korea, Republic of); Vetráková, Ľubica [Department of Chemistry and Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno (Czech Republic); Seo, Jiwon [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919 (Korea, Republic of); Heger, Dominik [Department of Chemistry and Research Centre for Toxic Compounds in the Environment (RECETOX), Faculty of Science, Masaryk University, Kamenice 5, 625 00 Brno (Czech Republic); Lee, Changha [School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919 (Korea, Republic of); Yoon, Ho-Il [Korea Polar Research Institute (KOPRI), Incheon 21990 (Korea, Republic of); Kim, Kitae, E-mail: ktkim@kopri.re.kr [Korea Polar Research Institute (KOPRI), Incheon 21990 (Korea, Republic of); Kim, Jungwon, E-mail: jwk@hallym.ac.kr [Department of Environmental Sciences and Biotechnology, Hallym University, Chuncheon, Gangwon-do 24252 (Korea, Republic of)

    2017-05-05

    Highlights: • Redox conversion of 4-CP/Cr(VI) was significantly accelerated during freezing. • Accelerated redox conversion in ice is ascribed to the freeze concentration effect. • 4-CP, Cr(VI), and protons are concentrated in the liquid brine by freezing. • Redox conversions of various phenolic pollutants/Cr(VI) were significant in ice. • Freezing-accelerated redox conversion was observed in real polluted water. - Abstract: The redox reaction between 4-chlorophenol (4-CP) and chromate (Cr(VI)) (i.e., the simultaneous oxidation of 4-CP by Cr(VI) and reduction of Cr(VI) by 4-CP) in ice (i.e., at −20 °C) was compared with the corresponding reaction in water (i.e., at 25 °C). The redox conversion of 4-CP/Cr(VI), which was negligible in water, was significantly accelerated in ice. This accelerated redox conversion of 4-CP/Cr(VI) in ice is ascribed to the freeze concentration effect occurring during freezing, which excludes solutes (i.e., 4-CP and Cr(VI)) and protons from the ice crystals and subsequently concentrates them in the liquid brine. The concentrations of Cr(VI) and protons in the liquid brine were confirmed by measuring the optical image and the UV–vis absorption spectra of cresol red (CR) as a pH indicator of frozen solution. The redox conversion of 4-CP/Cr(VI) was observed in water when the concentrations of 4-CP/protons or Cr(VI)/protons increased by 100/1000-fold. These results corroborate the freeze concentration effect as the reason for the accelerated redox conversion of 4-CP/Cr(VI) in ice. The redox conversion of various phenolic pollutants/Cr(VI) and 4-CP/Cr(VI) in real wastewater was successfully achieved in ice, which verifies the environmental relevance and importance of freezing-accelerated redox conversion of phenolic pollutants/Cr(VI) in cold regions.

  15. Accelerated redox reaction between chromate and phenolic pollutants during freezing

    International Nuclear Information System (INIS)

    Ju, Jinjung; Kim, Jaesung; Vetráková, Ľubica; Seo, Jiwon; Heger, Dominik; Lee, Changha; Yoon, Ho-Il; Kim, Kitae; Kim, Jungwon

    2017-01-01

    Highlights: • Redox conversion of 4-CP/Cr(VI) was significantly accelerated during freezing. • Accelerated redox conversion in ice is ascribed to the freeze concentration effect. • 4-CP, Cr(VI), and protons are concentrated in the liquid brine by freezing. • Redox conversions of various phenolic pollutants/Cr(VI) were significant in ice. • Freezing-accelerated redox conversion was observed in real polluted water. - Abstract: The redox reaction between 4-chlorophenol (4-CP) and chromate (Cr(VI)) (i.e., the simultaneous oxidation of 4-CP by Cr(VI) and reduction of Cr(VI) by 4-CP) in ice (i.e., at −20 °C) was compared with the corresponding reaction in water (i.e., at 25 °C). The redox conversion of 4-CP/Cr(VI), which was negligible in water, was significantly accelerated in ice. This accelerated redox conversion of 4-CP/Cr(VI) in ice is ascribed to the freeze concentration effect occurring during freezing, which excludes solutes (i.e., 4-CP and Cr(VI)) and protons from the ice crystals and subsequently concentrates them in the liquid brine. The concentrations of Cr(VI) and protons in the liquid brine were confirmed by measuring the optical image and the UV–vis absorption spectra of cresol red (CR) as a pH indicator of frozen solution. The redox conversion of 4-CP/Cr(VI) was observed in water when the concentrations of 4-CP/protons or Cr(VI)/protons increased by 100/1000-fold. These results corroborate the freeze concentration effect as the reason for the accelerated redox conversion of 4-CP/Cr(VI) in ice. The redox conversion of various phenolic pollutants/Cr(VI) and 4-CP/Cr(VI) in real wastewater was successfully achieved in ice, which verifies the environmental relevance and importance of freezing-accelerated redox conversion of phenolic pollutants/Cr(VI) in cold regions.

  16. Freezing process in unsaturated packed beds; Fuhowa ryushi sonai ni okeru suibun toketsu

    Energy Technology Data Exchange (ETDEWEB)

    Akahori, M; Aoki, K; Hattori, M [Nagaoka University of Technology, Niigata (Japan); Tani, T [Oji Paper Co. Ltd., Tokyo (Japan)

    1998-04-25

    The freezing process in unsaturated packed beds has been investigated experimentally and theoretically. Water transport to the frozen front plays an important part on freezing. The rate of the absorption of water into frozen layer depended on the freezing heat flux and the water saturation at the freezing front. As a result, ice content in the frozen layer was related to the rate of the absorption of water and the freezing heat flux. A one-dimensional freezing model in unsaturated packed beds has been presented, accounting for the water transport. The predicted water saturation and temperature distributions in the body and the thickness of frozen layer were compared with the experimental results using a porous bed composed of glass beads. 12 refs., 10 figs., 1 tab.

  17. Breeding of Freeze-tolerant Yeast and the Mechanisms of Stress-tolerance

    Science.gov (United States)

    Hino, Akihiro

    Frozen dough method have been adopted in the baking industry to reduce labor and to produce fresh breads in stores. New freeze-tolerant yeasts for frozen dough preparations were isolated from banana peel and identified. To obtain strains that have fermentative ability even after several months of frozen storage in fermented dough, we attempted to breed new freeze-tolerantstrain. The hybrid between S.cerevisiae, which is a isolated freeze-tolerant strain, and a strain isolated from bakers' yeast with sexual conjugation gave a good quality bread made from frozen dough method. Freeze-tolerant strains showed higher surviving and trehalose accumulating abilities than freeze-sensitive strains. The freeze tolerance of the yeasts was associated with the basal amount of intracellular trehalose after rapid degradation at the onset of the prefermentation period. The complicated metabolic pathway and the regulation system of trehalose in yeast cells are introduced. The trehalose synthesis may act as a metabolic buffer system which contribute to maintain the intracellular inorganic phosphate and as a feedback regulation system in the glycolysis. However, it is not known enough how the trehalose protects yeast cells from stress.

  18. Visual Indicators on Vaccine Boxes as Early Warning Tools to Identify Potential Freeze Damage.

    Science.gov (United States)

    Angoff, Ronald; Wood, Jillian; Chernock, Maria C; Tipping, Diane

    2015-07-01

    The aim of this study was to determine whether the use of visual freeze indicators on vaccines would assist health care providers in identifying vaccines that may have been exposed to potentially damaging temperatures. Twenty-seven sites in Connecticut involved in the Vaccine for Children Program participated. In addition to standard procedures, visual freeze indicators (FREEZEmarker ® L; Temptime Corporation, Morris Plains, NJ) were affixed to each box of vaccine that required refrigeration but must not be frozen. Temperatures were monitored twice daily. During the 24 weeks, all 27 sites experienced triggered visual freeze indicator events in 40 of the 45 refrigerators. A total of 66 triggered freeze indicator events occurred in all 4 types of refrigerators used. Only 1 of the freeze events was identified by a temperature-monitoring device. Temperatures recorded on vaccine data logs before freeze indicator events were within the 35°F to 46°F (2°C to 8°C) range in all but 1 instance. A total of 46,954 doses of freeze-sensitive vaccine were stored at the time of a visual freeze indicator event. Triggered visual freeze indicators were found on boxes containing 6566 doses (14.0% of total doses). Of all doses stored, 14,323 doses (30.5%) were of highly freeze-sensitive vaccine; 1789 of these doses (12.5%) had triggered indicators on the boxes. Visual freeze indicators are useful in the early identification of freeze events involving vaccines. Consideration should be given to including these devices as a component of the temperature-monitoring system for vaccines.

  19. Chromosomal integrity of freeze-dried mouse spermatozoa after 137Cs γ-ray irradiation

    International Nuclear Information System (INIS)

    Kusakabe, Hirokazu; Kamiguchi, Yujiroh

    2004-01-01

    This study demonstrated that freeze-dried mouse spermatozoa possess strong resistance to 137 Cs γ-ray irradiation at doses of up to 8 Gy. Freeze-dried mouse spermatozoa were rehydrated and injected into mouse oocytes with an intracytoplasmic sperm injection (ICSI) technique. Most oocytes can be activated after ICSI by using spermatozoa irradiated with γ-rays before and after freeze-drying. Sperm chromosome complements were analyzed at the first cleavage metaphase. Chromosome aberrations increased in a dose-dependent manner in the spermatozoa irradiated before freeze-drying. However, no increase in oocytes with chromosome aberrations was observed when fertilized by spermatozoa that had been irradiated after freeze-drying, as compared with freeze-dried spermatozoa that had not been irradiated. These results suggest that both the chromosomal integrity of freeze-dried spermatozoa, as well as their ability to activate oocytes, were protected from γ-ray irradiation at doses at which chromosomal damage is found to be strongly induced in spermatozoa suspended in solution

  20. Application of dual-cloud point extraction for the trace levels of copper in serum of different viral hepatitis patients by flame atomic absorption spectrometry: A multivariate study

    Science.gov (United States)

    Arain, Salma Aslam; Kazi, Tasneem G.; Afridi, Hassan Imran; Abbasi, Abdul Rasool; Panhwar, Abdul Haleem; Naeemullah; Shanker, Bhawani; Arain, Mohammad Balal

    2014-12-01

    An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu2+) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu2+ using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046 μg L-1 and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu2+ in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu2+ in serum samples of different viral hepatitis patients and healthy controls.

  1. Ultrasound assisted immersion freezing of broccoli (Brassica oleracea L. var. botrytis L.).

    Science.gov (United States)

    Xin, Ying; Zhang, Min; Adhikari, Benu

    2014-09-01

    The aim of this study was to research the ultrasound-assisted freezing (UAF) of broccoli. CaCl2 solution was used as freezing medium. The comparative advantage of using UAF over normal freezing on the freezing time, cell-wall bound calcium to total calcium ratio, textural properties, color, drip loss and L-ascorbic acid contents was evaluated. The application of UAF at selected acoustic intensity with a range of 0.250-0.412 W/cm(2) decreased the freezing time and the loss of cell-wall bound calcium content. Compared to normal freezing, the values of textural properties, color, L-ascorbic acid content were better preserved and the drip loss was significantly minimized by the application of UAF. However, when outside that range of acoustic intensity, the quality of the ultrasound-assisted frozen broccoli was inferior compared to that of the normally frozen samples. Selected the appropriate acoustic intensity was very important for the application of UAF. Copyright © 2014 Elsevier B.V. All rights reserved.

  2. Cognitive Contributions to Freezing of Gait in Parkinson Disease: Implications for Physical Rehabilitation.

    Science.gov (United States)

    Peterson, Daniel S; King, Laurie A; Cohen, Rajal G; Horak, Fay B

    2016-05-01

    People with Parkinson disease (PD) who show freezing of gait also have dysfunction in cognitive domains that interact with mobility. Specifically, freezing of gait is associated with executive dysfunction involving response inhibition, divided attention or switching attention, and visuospatial function. The neural control impairments leading to freezing of gait have recently been attributed to higher-level, executive and attentional cortical processes involved in coordinating posture and gait rather than to lower-level, sensorimotor impairments. To date, rehabilitation for freezing of gait primarily has focused on compensatory mobility training to overcome freezing events, such as sensory cueing and voluntary step planning. Recently, a few interventions have focused on restitutive, rather than compensatory, therapy. Given the documented impairments in executive function specific to patients with PD who freeze and increasing evidence of overlap between cognitive and motor function, incorporating cognitive challenges with mobility training may have important benefits for patients with freezing of gait. Thus, a novel theoretical framework is proposed for exercise interventions that jointly address both the specific cognitive and mobility challenges of people with PD who freeze. © 2016 American Physical Therapy Association.

  3. SOME STUDIES ABOUT CEREALS BEHAVIOR DURING FREEZE DRYING PROCESS

    Directory of Open Access Journals (Sweden)

    GABRIELA-VICTORIA MNERIE

    2009-05-01

    Full Text Available The paper presents some special method and equipment and the principal advantages of freeze-dried food. The freeze drying is a good method of freeze-drying for make some experiments with many kind of cereals, for the improvement that in food production. It is necessary and is possible to study the corn oil extract, wheat flour, the maltodextrin from corn, modified cornstarch, spice extracts, soy sauce, hydrolyzed wheat gluten, partially hydrogenated soybean and cottonseed oil etc. That is very porous, since it occupies the same volume as the original and so rehydrates rapidly. There is less loss of flavour and texture than with most other methods of drying.

  4. [Freeze drying process optimization of ginger juice-adjuvant for Chinese materia medica processing and stability of freeze-dried ginger juice powder].

    Science.gov (United States)

    Yang, Chun-Yu; Guo, Feng-Qian; Zang, Chen; Cao, Hui; Zhang, Bao-Xian

    2018-02-01

    Ginger juice, a commonly used adjuvant for Chinese materia medica, is applied in processing of multiple Chinese herbal decoction pieces. Because of the raw materials and preparation process of ginger juice, it is difficult to be preserved for a long time, and the dosage of ginger juice in the processing can not be determined base on its content of main compositions. Ginger juice from different sources is hard to achieve consistent effect during the processing of traditional Chinese herbal decoction pieces. Based on the previous studies, the freeze drying of ginger juice under different shelf temperatures and vacuum degrees were studied, and the optimized freeze drying condition of ginger juice was determined. The content determination method for 6-gingerol, 8-gingerol, 10-gingerol and 6-shagaol in ginger juice and redissolved ginger juice was established. The content changes of 6-gingerol, 8-gingerol, 10-gingerol, 6-gingerol, 6-shagaol, volatile oil and total phenol were studied through the drying process and 30 days preservation period. The results showed that the freeze drying time of ginger juice was shortened after process optimization; the compositions basically remained unchanged after freeze drying, and there was no significant changes in the total phenol content and gingerol content, but the volatile oil content was significantly decreased( P <0.05). Within 30 days, the contents of gingerol, total phenol, and volatile oil were on the decline as a whole. This study has preliminarily proved the feasibility of freeze-drying process of ginger juice as an adjuvant for Chinese medicine processing. Copyright© by the Chinese Pharmaceutical Association.

  5. The impact of freeze-drying on microstructure and rehydration properties of carrot

    NARCIS (Netherlands)

    Voda, A.; Homan, N.; Witek, M.; Duijster, A.; Dalen, van G.; Sman, van der R.G.M.; Nijsse, J.; Vliet, van L.J.; As, van H.; Duynhoven, van J.P.M.

    2012-01-01

    The impact of freeze-drying, blanching and freezing rate pre-treatments on the microstructure and on the rehydration properties of winter carrots were studied by µCT, SEM, MRI and NMR techniques. The freezing rate determines the size of ice crystals being formed that leave pores upon drying. Their

  6. Preparation of Tc-99m human serum albumin using stannous citrate and stannous chloride

    International Nuclear Information System (INIS)

    El-Asrag, H.A.; El-Wetery, A.S.; El-Mohty, A.A.

    1988-01-01

    99mTc-albumin is widely used as radioactive indicator in the measurement of cardiac output by external counting techniques and in blood volume studies. The quality of 99mTc-albumin depends on the method of preparation. A comparative study had been carried out on the 99mTc-albumin preparation by the stannous chloride, stannous tartarate and stannous citrate method. The different parameters investigated for each method include: pH, albumin concentration, reductant concentration and ascorbic acid as antioxidant stabilizer. The biological distribution of 99mTc-albumin, prepared by different methods, were determined in mice and rats. A procedure was developed for the preparation of stannous human serum albumin (HSA) kit for human application the kit provides a freeze dried sterile formulation for reconstitution with sterile 99mTc pertechnetate solution to give 99mTc-Hsa, the effect of irradiation sterilization on the freeze dried kit was studied by spectrophotometric determination and biological distribution in mice and rats

  7. Nitrogen deposition may enhance soil carbon storage via change of soil respiration dynamic during a spring freeze-thaw cycle period.

    Science.gov (United States)

    Yan, Guoyong; Xing, Yajuan; Xu, Lijian; Wang, Jianyu; Meng, Wei; Wang, Qinggui; Yu, Jinghua; Zhang, Zhi; Wang, Zhidong; Jiang, Siling; Liu, Boqi; Han, Shijie

    2016-06-30

    As crucial terrestrial ecosystems, temperate forests play an important role in global soil carbon dioxide flux, and this process can be sensitive to atmospheric nitrogen deposition. It is often reported that the nitrogen addition induces a change in soil carbon dioxide emission in growing season. However, the important effects of interactions between nitrogen deposition and the freeze-thaw-cycle have never been investigated. Here we show nitrogen deposition delays spikes of soil respiration and weaken soil respiration. We found the nitrogen addition, time and nitrogen addition×time exerted the negative impact on the soil respiration of spring freeze-thaw periods due to delay of spikes and inhibition of soil respiration (p nitrogen), 39% (medium-nitrogen) and 36% (high-nitrogen) compared with the control. And the decrease values of soil respiration under medium- and high-nitrogen treatments during spring freeze-thaw-cycle period in temperate forest would be approximately equivalent to 1% of global annual C emissions. Therefore, we show interactions between nitrogen deposition and freeze-thaw-cycle in temperate forest ecosystems are important to predict global carbon emissions and sequestrations. We anticipate our finding to be a starting point for more sophisticated prediction of soil respirations in temperate forests ecosystems.

  8. Physicochemical interaction mechanism between nanoparticles and tetrasaccharides (stachyose) during freeze-drying.

    Science.gov (United States)

    Kamiya, Seitaro; Nakashima, Kenichiro

    2017-12-01

    Nanoparticle suspensions are thermodynamically unstable and subject to aggregation. Freeze-drying on addition of saccharides is a useful method for preventing aggregation. In the present study, tetrasaccharides (stachyose) was employed as an additive. In addition, we hypothesize the interactive mechanism between stachyose and the nanoparticles during freeze-drying for the first time. The mean particle size of the rehydrated freeze-dried stachyose-containing nanoparticles (104.7 nm) was similar to the initial particle size before freeze-drying (76.8 nm), indicating that the particle size had been maintained. The mean particle size of the rehydrated normal-dried stachyose-containing nanoparticles was 222.2 nm. The powder X-ray diffraction of the freeze-dried stachyose-containing nanoparticles revealed a halo pattern. The powder X-ray diffraction of the normally dried stachyose-containing nanoparticles produced mainly a halo pattern and a partial peak. These results suggest an interaction between the nanoparticles and stachyose, and that this relationship depends on whether the mixture is freeze-dried or dried normally. In the case of normal drying, although most molecules cannot move rapidly thereby settling irregularly, some stachyose molecules can arrange regularly leading to some degree of crystallization and potentially some aggregation. In contrast, during freeze-drying, the moisture sublimed, while the stachyose molecules and nanoparticles were immobilized in the ice. After sublimation, stachyose remained in the space occupied by water and played the role of a buffer material, thus preventing aggregation.

  9. Freeze Tolerance of Seed-Producing Turf Bermudagrasses.

    Science.gov (United States)

    Anderson, Jeffrey A.; Taliaferro, Charles M.

    2002-01-01

    Bermudagrass, Cynodon dactylon (L.) Pers., suffers periodic severe winter-kill throughout much of its area of use in the contiguous USA. A research goal is to increase freeze tolerance in cultivars to lessen the risk of such damage. An identified research need is for Cynodon germplasm resources to be characterized for freeze tolerance and hybridization potential. Accordingly, the objective of this research was to characterize the relative freeze tolerance of selected fertile bermudagrass plants. Nine tetraploid (2n = 4x = 36) C. dactylon and two triploid (2n = 3x = 27) hybrid (C. dactylon x C. transvaalensis Burtt Davy) clonal plants (standards) were evaluated in two experiments. Plants were propagated clonally and established in Cone-tainers (Ray Leach Cone-tainer Nursery, Canby, OR) for about 10 wk. Acclimation took place for 4 wk in controlled environment chambers at 8/2 degrees C (day/night) temperatures with a 10-h photoperiod. Following acclimation, Cone-tainers were placed into a freeze chamber and cooled rapidly to -2 degrees C, induced to freeze with ice chips, then held overnight at -2 degrees C. The freeze chamber was then programmed to cool linearly at 1 degrees C per hour. For each cultivar, three Cone-tainers were removed at each test temperature. Following thawing, Cone-tainers were transferred to a greenhouse and regrowth was evaluated visually. Nonlinear regression was used to estimate T(mid), which corresponded to the midpoint of the sigmoidal response curve of survival vs temperature. Within experiment one, Tifgreen (T(mid) = -7.2 degrees C) was significantly less cold hardy than Quickstand (-9.0 degrees C), A-12204 (-9.2 degrees C), Midiron (-9.9 degrees C), and A-12195 (-10.5 degrees C). A-12195 was significantly hardier than all genotypes except Midiron. In the second experiment, Arizona Common (-6.6 degrees C), Tifgreen (-7.1 degrees C), and A-12205 (-7.1 degrees C) were less hardy than A-9959 (-8.7 degrees C), A-12156 (-8.9 degrees C), A

  10. Validation of the shake test for detecting freeze damage to adsorbed vaccines.

    Science.gov (United States)

    Kartoglu, Umit; Ozgüler, Nejat Kenan; Wolfson, Lara J; Kurzatkowski, Wiesław

    2010-08-01

    To determine the validity of the shake test for detecting freeze damage in aluminium-based, adsorbed, freeze-sensitive vaccines. A double-blind crossover design was used to compare the performance of the shake test conducted by trained health-care workers (HCWs) with that of phase contrast microscopy as a "gold standard". A total of 475 vials of 8 different types of World Health Organization prequalified freeze-sensitive vaccines from 10 different manufacturers were used. Vaccines were kept at 5 degrees C. Selected numbers of vials from each type were then exposed to -25 degrees C and -2 degrees C for 24-hour periods. There was complete concordance between HCWs and phase-contrast microscopy in identifying freeze-damaged vials and non-frozen samples. Non-frozen samples showed a fine-grain structure under phase contrast microscopy, but freeze-damaged samples showed large conglomerates of massed precipitates with amorphous, crystalline, solid and needle-like structures. Particles in the non-frozen samples measured from 1 microm (vaccines against diphtheria-tetanus-pertussis; Haemophilus influenzae type b; hepatitis B; diphtheria-tetanus-pertussis-hepatitis B) to 20 microm (diphtheria and tetanus vaccines, alone or in combination). By contrast, aggregates in the freeze-damaged samples measured up to 700 microm (diphtheria-tetanus-pertussis) and 350 microm on average. The shake test had 100% sensitivity, 100% specificity and 100% positive predictive value in this study, which confirms its validity for detecting freeze damage to aluminium-based freeze-sensitive vaccines.

  11. The human milk oligosaccharides are not affected by pasteurization and freeze-drying.

    Science.gov (United States)

    Hahn, Won-Ho; Kim, Jaehan; Song, Seunghyun; Park, Suyeon; Kang, Nam Mi

    2017-11-06

    Human milk oligosaccharides (HMOs) are known as important factors in neurologic and immunologic development of neonates. Moreover, freeze-drying seems to be a promising storage method to improve the processes of human milk banks. However, the effects of pasteurization and freeze-drying on HMOs were not evaluated yet. The purpose of this study is to analyze and compare the HMOs profiles of human milk collected before and after the pasteurization and freeze-drying. Totally nine fresh human milk samples were collected from three healthy mothers at the first, second, and third week after delivery. The samples were treated with Holder pasteurization and freeze-drying. HMOs profiles were analyzed by matrix-assisted laser desorption/ionization (MALDI) time-of-flight/time-of-flight (TOF/TOF) mass spectrometry and compared between samples collected before and after the treatments. Human milk samples showed significantly different HMO patterns between mothers. However, HMOs were not affected by lactation periods within 3 weeks after delivery (r 2  = 0.972-0.999, p pasteurization and freeze-drying were found not to affect HMO patterns in a correlation analysis (r 2  = 0.989-0.999, p pasteurization and freeze-drying of donor milks. We hope that introducing freeze-drying to the human milk banks would be encouraged by the present study. However, the storage length without composition changes of HMOs after freeze-drying needs to be evaluated in the further studies.

  12. Normal freezing of ideal ternary systems of the pseudobinary type

    Science.gov (United States)

    Li, C. H.

    1972-01-01

    Perfect liquid mixing but no solid diffusion is assumed in normal freezing. In addition, the molar compositions of the freezing solid and remaining liquid, respectively, follow the solidus and liquidus curves of the constitutional diagram. For the linear case, in which both the liquidus and solidus are perfectly straight lines, the normal freezing equation giving the fraction solidified at each melt temperature and the solute concentration profile in the frozen solid was determined as early as 1902, and has since been repeatedly published. Corresponding equations for quadratic, cubic or higher-degree liquidus and solidus lines have also been obtained. The equation of normal freezing for ideal ternary liquid solutions solidified into ideal solid solutions of the pseudobinary type is given. Sample computations with the use of this new equation were made and are given for the Ga-Al-As system.

  13. Freezing and melting line invariants of the Lennard-Jones system

    DEFF Research Database (Denmark)

    Costigliola, Lorenzo; Schrøder, Thomas; Dyre, Jeppe C.

    2016-01-01

    The invariance of several structural and dynamical properties of the Lennard-Jones (LJ) system along the freezing and melting lines is interpreted in terms of isomorph theory. First the freezing/melting lines of the LJ system are shown to be approximated by isomorphs. Then we show...... that the invariants observed along the freezing and melting isomorphs are also observed on other isomorphs in the liquid and crystalline phases. The structure is probed by the radial distribution function and the structure factor and dynamics are probed by the mean-square displacement, the intermediate scattering...... function, and the shear viscosity. Studying these properties with reference to isomorph theory explains why the known single-phase melting criteria hold, e.g., the Hansen–Verlet and the Lindemann criteria, and why the Andrade equation for the viscosity at freezing applies, e.g., for most liquid metals. Our...

  14. FY 2017 Status of Sodium Freezing and Remelting Tests

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Q. [Argonne National Lab. (ANL), Argonne, IL (United States); Boron, E. [Argonne National Lab. (ANL), Argonne, IL (United States); Momozaki, Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Chojnowski, D. B. [Argonne National Lab. (ANL), Argonne, IL (United States); Sienicki, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Reed, C. B. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-09-15

    The Sodium Freezing and Remelting experiment facility at Argonne National Laboratory has been significantly modified and improved. The main improvement was replacement of the two original stainless steel test sections that had strain gages limited by their bonds to the stainless steel to maximum temperatures of 350°C with a single new test section with strain gages that can be utilized up to 980°C and a thin wall to enhance measured strains. Wetting of stainless steel by sodium within a practical time of one to a few days is expected to require temperatures of 450°C or greater. Thus, the higher temperature strain gages enable wetting in a short time of a few days. Wetting below 350°C would have required an impractically long time of at least weeks. Other improvements included upgrading of the loop configuration, incorporation of a cold finger to purify sodium, a new data acquisition system, and reinstallation of the many heaters, heater controllers, and thermocouples. After the loop had been heated to 400°C for about two hours, an initial sodium freezing test was conducted. It is thought that the sodium might have at least partially wetted the stainless steel wall under these conditions. The strain gage measurements indicate that an incremental step inward deformation of the test section thin wall occurred as the temperature decreased through the sodium freezing temperature. This behavior is consistent with sodium initially adhering to the stainless steel inner wall but breaking away from the wall as the freezing sodium contracted. Conduct of additional sodium freezing tests under well wetted conditions was prevented as a result of stoppage of all electrical work at Argonne by the Laboratory Director on July 25, 2017. A pathway to resuming electrical work is now in place at Argonne and additional sodium freezing testing will resume next fiscal year.

  15. Saccharomyces cerevisiae glycerol/H+ symporter Stl1p is essential for cold/near-freeze and freeze stress adaptation. A simple recipe with high biotechnological potential is given

    Directory of Open Access Journals (Sweden)

    Ferreira Célia

    2010-11-01

    Full Text Available Abstract Background Freezing is an increasingly important means of preservation and storage of microbial strains used for many types of industrial applications including food processing. However, the yeast mechanisms of tolerance and sensitivity to freeze or near-freeze stress are still poorly understood. More knowledge on this regard would improve their biotechnological potential. Glycerol, in particular intracellular glycerol, has been assigned as a cryoprotectant, also important for cold/near-freeze stress adaptation. The S. cerevisiae glycerol active transporter Stl1p plays an important role on the fast accumulation of glycerol. This gene is expressed under gluconeogenic conditions, under osmotic shock and stress, as well as under high temperatures. Results We found that cells grown on STL1 induction medium (YPGE and subjected to cold/near-freeze stress, displayed an extremely high expression of this gene, also visible at glycerol/H+ symporter activity level. Under the same conditions, the strains harbouring this transporter accumulated more than 400 mM glycerol, whereas the glycerol/H+ symporter mutant presented less than 1 mM. Consistently, the strains able to accumulate glycerol survive 25-50% more than the stl1Δ mutant. Conclusions In this work, we report the contribution of the glycerol/H+ symporter Stl1p for the accumulation and maintenance of glycerol intracellular levels, and consequently cell survival at cold/near-freeze and freeze temperatures. These findings have a high biotechnological impact, as they show that any S. cerevisiae strain already in use can become more resistant to cold/freeze-thaw stress just by simply adding glycerol to the broth. The combination of low temperatures with extracellular glycerol will induce the transporter Stl1p. This solution avoids the use of transgenic strains, in particular in food industry.

  16. Freeze desalination of seawater using LNG cold energy

    KAUST Repository

    Chang, Jian; Zuo, Jian; Lu, Kang-Jia; Chung, Neal Tai-Shung

    2016-01-01

    With the aid of cold energy from regasification of liquefied natural gas (LNG), freeze desalination (FD) is an emerging technology for seawater desalination because of its low energy characteristics and insensitivities to fouling problems. This work aims to investigate the major operating parameters of FD such as coolant temperature, freezing duration, supercooling, seeding, agitation, crystallizer material and subsequent washing procedure on ice production and water quality. It was found that the optimal freezing duration per batch was 1 h for an iron crystallizer and 1.5 h for a glass crystallizer. The optimal coolant temperature should be around −8 °C. The optimal amount of washing water to clean the raw ice was about 50 wt% of the raw ice. Over 50 wt% of the feed could be recovered as raw ice within 1 h, which means an overall ice recovery rate of higher than 25% (of the original seawater), considering the consumption of washing water. Both artificial and real seawater were tested under the optimized conditions. The total dissolved solid in the product ice was around 300 ppm, which met the World Health Organization (WHO) potable water salinity standard of 500 ppm. Therefore, the process parameters optimized in this study can be directly used for the freeze desalination of seawater.

  17. Freeze desalination of seawater using LNG cold energy

    KAUST Repository

    Chang, Jian

    2016-06-23

    With the aid of cold energy from regasification of liquefied natural gas (LNG), freeze desalination (FD) is an emerging technology for seawater desalination because of its low energy characteristics and insensitivities to fouling problems. This work aims to investigate the major operating parameters of FD such as coolant temperature, freezing duration, supercooling, seeding, agitation, crystallizer material and subsequent washing procedure on ice production and water quality. It was found that the optimal freezing duration per batch was 1 h for an iron crystallizer and 1.5 h for a glass crystallizer. The optimal coolant temperature should be around −8 °C. The optimal amount of washing water to clean the raw ice was about 50 wt% of the raw ice. Over 50 wt% of the feed could be recovered as raw ice within 1 h, which means an overall ice recovery rate of higher than 25% (of the original seawater), considering the consumption of washing water. Both artificial and real seawater were tested under the optimized conditions. The total dissolved solid in the product ice was around 300 ppm, which met the World Health Organization (WHO) potable water salinity standard of 500 ppm. Therefore, the process parameters optimized in this study can be directly used for the freeze desalination of seawater.

  18. A New Freezing Method Using Pre-Dehydration by Microwave-Vacuum Drying

    Science.gov (United States)

    Tsuruta, Takaharu; Hamidi, Nurkholis

    Partial dehydration by microwave-vacuum drying has been applied to tuna and strawberry in order to reduce cell-damages caused by the formation of large ice-crystals during freezing. The samples were subjected to microwave vacuum drying at pressure of 5 kPa and temperature less than 27°C to remove small amount of water prior to freezing. The tuna were cooled by using the freezing chamber at temperature -50°C or -150°C, while the strawberries were frozen at temperature -30°C or -80°C, respectively. The temperature transients in tuna showed that removing some water before freezing made the freezing time shorter. The observations of ice crystal clearly indicated that rapid cooling and pre-dehydration prior to freezing were effective in minimizing the size of ice crystal. It is also understood that the formation of large ice crystals has a close relation to the cell damages. After thawing, the observation of microstructure was done on the tuna and strawberry halves. The pre-dehydrated samples showed a better structure than the un-dehydrated one. It is concluded that the pre-dehydration by microwave-vacuum drying is one promising method for the cryo-preservation of foods.

  19. A subspecies of region crossing change, region freeze crossing change

    OpenAIRE

    Inoue, Ayumu; Shimizu, Ryo

    2016-01-01

    We introduce a local move on a link diagram named a region freeze crossing change which is close to a region crossing change, but not the same. We study similarity and difference between region crossing change and region freeze crossing change.

  20. Giant panda (Ailuropoda melanoleuca) sperm morphometry and function after repeated freezing and thawing.

    Science.gov (United States)

    Santiago-Moreno, J; Esteso, M C; Pradiee, J; Castaño, C; Toledano-Díaz, A; O'Brien, E; Lopez-Sebastián, A; Martínez-Nevado, E; Delclaux, M; Fernández-Morán, J; Zhihe, Z

    2016-05-01

    This work examines the effects of subsequent cycles of freezing-thawing on giant panda (Ailuropoda melanoleuca) sperm morphometry and function, and assesses whether density-gradient centrifugation (DGC) can increase the number of freezing-thawing cycles this sperm can withstand. A sperm sample was collected by electroejaculation from a mature giant panda and subjected to five freezing-thawing cycles. Although repeated freezing-thawing negatively affected (P 60% of the sperm cells in both treatments showed acrosome integrity even after the fifth freezing cycle. In fresh semen, the sperm head length was 4.7 μm, the head width 3.6 μm, area 14.3 μm(2) and perimeter length 14.1 μm. The present results suggest that giant panda sperm trends to be resistant to repeated freezing-thawing, even without DGC selection. © 2015 Blackwell Verlag GmbH.

  1. Gelatin-Filtered Consomme: A Practical Demonstration of the Freezing and Thawing Processes

    Science.gov (United States)

    Lahne, Jacob B.; Schmidt, Shelly J.

    2010-01-01

    Freezing is a key food processing and preservation technique widely used in the food industry. Application of best freezing and storage practices extends the shelf-life of foods for several months, while retaining much of the original quality of the fresh food. During freezing, as well as its counterpart process, thawing, a number of critical…

  2. Geometric origin of dynamically induced freezing of quantum evolution

    International Nuclear Information System (INIS)

    Matos-Abiague, A.; Berakdar, J.

    2006-01-01

    The phenomenon of dynamical, field-induced freezing of quantum evolution is discussed. It occurs when a time-dependent state is dynamically driven in such a way that the evolution of the corresponding wave function is effectively localized within a small region in the projective Hilbert space. As a consequence, the dynamics of the system is frozen and the expectation values of all physical observables hardly change with time. Necessary and sufficient conditions for inducing dynamical freezing are inferred from a general analysis of the geometry of quantum evolution. The relevance of the dynamical freezing for a sustainable in time, dynamical control is discussed and exemplified by a study of the coherent control of the kicked rotor motion

  3. Improved cryopreservability of stallion sperm using a sorbitol-based freezing extender.

    Science.gov (United States)

    Pojprasath, T; Lohachit, C; Techakumphu, M; Stout, T; Tharasanit, T

    2011-06-01

    Cryopreservation of stallion semen is often associated with poor post-thaw sperm quality. Sugars are among the important components of a freezing extender and act as non-permeating cryoprotectants. This study aimed to compare the quality of stallion sperm frozen with glucose, fructose or sorbitol-containing freezing extenders. Semen was collected from six stallions of proven fertility and cryopreserved using a freezing extender containing different types of monosaccharide sugars (glucose, fructose or sorbitol). After thawing, the semen was examined for sperm motility, viability, acrosome integrity, plasma membrane functionality and sperm longevity. The fertility of semen frozen in the presence of sorbitol was also tested by artificial insemination. Sperm quality was significantly decreased following freezing and thawing (P sorbitol and glucose (P sorbitol-based extender when examined at 2 and 4 h post-thaw, all of these parameters plus plasma membrane functionality were improved for sperm frozen in the sorbitol extender than in the glucose extender when examined 10 min post-thaw. Two of four mares (50%) inseminated with semen frozen with a sorbitol-containing freezing extender became pregnant. It is concluded that different sugars have different abilities to protect against cryoinjury during freezing and thawing of stallion sperm. This study demonstrated that an extender containing sorbitol as primary sugar can be used to successfully cryopreserve equine sperm; moreover, the quality of frozen-thawed sperm appeared to be better than when glucose or fructose was the principle sugar in the freezing extender. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. Colder freeze-in axinos decaying into photons

    Science.gov (United States)

    Bae, Kyu Jung; Kamada, Ayuki; Liew, Seng Pei; Yanagi, Keisuke

    2018-03-01

    We point out that 7 keV axino dark matter (DM) in the R-parity violating (RPV) supersymmetric (SUSY) Dine-Fischler-Srednicki-Zhitnitsky axion model can simultaneously reproduce the 3.5 keV x-ray line excess and evade stringent constraints from the Ly -α forest data. Peccei-Quinn symmetry breaking naturally generates both the TeV-scale μ term and the MeV-scale RPV term. The RPV term introduces a tiny axino-neutrino mixing and provides axino DM as a variant of the sterile neutrino DM explaining the 3.5 keV x-ray line excess. Axinos are produced by freeze-in processes via the μ term. The resultant phase space distribution tends to be colder than the Fermi-Dirac distribution. The inherent entropy production from late-time saxion decay makes axinos even colder than those without saxion decay. The resultant axino DM takes the correct relic density and is compatible even with the latest and strongest constraint from the Ly-α forest data.

  5. Do freeze events create a demographic bottleneck for Colophospermum mopane?

    CSIR Research Space (South Africa)

    Whitecross, MA

    2012-11-01

    Full Text Available capacity of the effected plants. A severely freeze-damaged stand of Colophospermum mopane along a slope in the Venetia Limpopo Nature Reserve provided an opportunity to investigate the nature of freeze-damage impacts on C. mopane. Is this disturbance a...

  6. Influence of the freezing process on the pore structure of freeze-dried collagen sponges; Einfluss des Einfriervorganges auf die Porenstruktur gefriergetrockneter Kollagenschwaemme

    Energy Technology Data Exchange (ETDEWEB)

    Schoof, H.; Bruns, L.; Apel, J.; Heschel, I.; Rau, G. [Helmholz-Inst. fuer Biomedizinische Technik, Aachen (Germany)

    1997-12-31

    Freeze-dried sponges are used as colonisable tissue implants. As their porous structure is important for rapid colonisation it was found desirable to be able to produce homogeneous pore structures to specification. The structure of freeze-dried sponges is largely the same as the ice crystal morphology of frozen samples. In industrial manufacture suspensions are solidified in a cold bath. Freezing conditions are not stationary in this process, rendering ice crystal morphology inhomogeneous. However, studies on directed solidification as it is used in the Bridgman or the power-down method have shown that certain freezing conditions permit the production of collagen sponges of homogenous predefined pore size. [Deutsch] Gefriergetrocknete Kollagenschwaemme werden als besiedelbare Gewebeimplantate eingesetzt. Da die poroese Struktur fuer eine zuegige Besiedelung von grosser Bedeutung ist, sollen Kollagenschwaemme mit einer einstellbaren und homogenen Porenstruktur hergestellt werden. Die Struktur der gefriergetrockneten Schwaemme entspricht weitestgehend der Eiskristallmorphologie der gefrorenen Probe. Bei der industriellen Herstellung werden Suspensionen in einem Kaeltebad erstarrt. Die Einfrierbedingungen sind dabei nicht stationaer, was zu einer inhomogenen Eiskristallmorphologie fuehrt. Untersuchungen zur gerichteten Erstarrung nach dem Bridgman- und dem Power-Down-Verfahren ergaben jedoch, dass unter bestimmten Einfrierbedingungen Kollagenschwaemme mit homogener und definierbarer Porengroesse hergestellt werden koennen. (orig.)

  7. NMR Pore Structure and Dynamic Characteristics of Sandstone Caused by Ambient Freeze-Thaw Action

    Directory of Open Access Journals (Sweden)

    Bo Ke

    2017-01-01

    Full Text Available For a deeper understanding of the freeze-thaw weathering effects on the microstructure evolution and deterioration of dynamic mechanical properties of rock, the present paper conducted the nuclear magnetic resonance (NMR tests and impact loading experiments on sandstone under different freeze-thaw cycles. The results of NMR test show that, with the increase of freeze-thaw cycles, the pores expand and pores size tends to be uniform. The experimental results show that the stress-strain curves all go through four stages, namely, densification, elasticity, yielding, and failure. The densification curve is shorter, and the slope of elasticity curve decreases as the freeze-thaw cycles increase. With increasing freeze-thaw cycles, the dynamic peak stress decreases and energy absorption of sandstone increases. The dynamic failure form is an axial splitting failure, and the fragments increase and the size diminishes with increasing freeze-thaw cycles. The higher the porosity is, the more severe the degradation of dynamic characteristics is. An increase model for the relationships between the porosity or energy absorption and freeze-thaw cycles number was built to reveal the increasing trend with the freeze-thaw cycles increase; meanwhile, a decay model was built to predict the dynamic compressive strength degradation of rock after repeated freeze-thaw cycles.

  8. Degradation of ATP and glycogen in cod ( Gadus morhua ) muscle during freezing

    DEFF Research Database (Denmark)

    Cappeln, Gertrud; Jessen, Flemming

    2001-01-01

    Changes in ATP, IMP, lactate and glycogen contents in the muscle of cod were followed during freezing at temperatures of -20C and -45C. ATP degradation was accompanied by a corresponding increase in IMP content. Simultaneous measurement of temperature showed that at both freezing rates......, the greatest decrease in ATP content was observed when the temperature reached -0.8C. Glycolysis occurred during freezing of cod as indicated by an increase in lactate content. The changes found in all measured metabolites were more pronounced when freezing was performed at a slow rate compared to a fast rate...

  9. Freeze-all policy: fresh vs. frozen-thawed embryo transfer.

    Science.gov (United States)

    Roque, Matheus; Valle, Marcello; Guimarães, Fernando; Sampaio, Marcos; Geber, Selmo

    2015-05-01

    To compare in vitro fertilization (IVF) outcomes between fresh embryo transfer (ET) and frozen-thawed ET (the "freeze-all" policy), with fresh ET performed only in cases without progesterone (P) elevation. Prospective, observational, cohort study. Private IVF center. A total of 530 patients submitted to controlled ovarian stimulation (COS) with a gonadotropin-releasing hormone-antagonist protocol, and cleavage-stage, day-3 ET. None. Ongoing pregnancy rates. A total of 530 cycles were included in the analysis: 351 in the fresh ET group (when P levels were ≤1.5 ng/mL on the trigger day); and 179 cycles in the freeze-all group (ET performed after endometrial priming with estradiol valerate, at 6 mg/d, taken orally). For the fresh ET group vs. the freeze-all group, respectively, the implantation rate was 19.9% and 26.5%; clinical pregnancy rate was 35.9% and 46.4%; and ongoing pregnancy rate was 31.1% and 39.7%. The IVF outcomes were significantly better in the group using the freeze-all policy, compared with the group using fresh ET. These results suggest that even in a select group of patients that underwent fresh ET (P levels ≤1.5 ng/mL), endometrial receptivity may have been impaired by COS, and outcomes may be improved by using the freeze-all policy. Copyright © 2015 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  10. Bulk specimen X-ray microanalysis of freeze-fractured, freeze-dried tissues in gerontological research

    International Nuclear Information System (INIS)

    Nagy, I.

    1988-01-01

    The rationale for choosing the freeze-fracture freeze-drying (FFFD) method of biological bulk specimen preparation as well as the theoretical and practical problems of this method are treated. FFFD specimens are suitable for quantitative X-ray microanalysis of biologically relevant elements. Although the spatial resolution of this analytical technique is low, the application of properly selected bulk standard crystals as well as the measurement of the intracellular water and dry mass content by means of another method developed in the same laboratory, allow us to obtain useful information about the age-dependent changes of ionic composition in the main intracellular compartments. The paper summarizes the problems with regard to specimen preparation, beam penetration and the quantitative analysis of FFFD specimens. The method has been applied so far mainly for the analysis of intranuclear and intracytoplasmic concentrations of Na, C1 and K in various types of cells and has resulted in a significant contribution to our understanding of the cellular mechanisms of aging. 84 references

  11. Application of dual-cloud point extraction for the trace levels of copper in serum of different viral hepatitis patients by flame atomic absorption spectrometry: a multivariate study.

    Science.gov (United States)

    Arain, Salma Aslam; Kazi, Tasneem G; Afridi, Hassan Imran; Abbasi, Abdul Rasool; Panhwar, Abdul Haleem; Naeemullah; Shanker, Bhawani; Arain, Mohammad Balal

    2014-12-10

    An efficient, innovative preconcentration method, dual-cloud point extraction (d-CPE) has been developed for the extraction and preconcentration of copper (Cu(2+)) in serum samples of different viral hepatitis patients prior to couple with flame atomic absorption spectrometry (FAAS). The d-CPE procedure was based on forming complexes of elemental ions with complexing reagent 1-(2-pyridylazo)-2-naphthol (PAN), and subsequent entrapping the complexes in nonionic surfactant (Triton X-114). Then the surfactant rich phase containing the metal complexes was treated with aqueous nitric acid solution, and metal ions were back extracted into the aqueous phase, as second cloud point extraction stage, and finally determined by flame atomic absorption spectrometry using conventional nebulization. The multivariate strategy was applied to estimate the optimum values of experimental variables for the recovery of Cu(2+) using d-CPE. In optimum experimental conditions, the limit of detection and the enrichment factor were 0.046μgL(-1) and 78, respectively. The validity and accuracy of proposed method were checked by analysis of Cu(2+) in certified sample of serum (CRM) by d-CPE and conventional CPE procedure on same CRM. The proposed method was successfully applied to the determination of Cu(2+) in serum samples of different viral hepatitis patients and healthy controls. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Scaling-Up Eutectic Freeze Crystallization

    NARCIS (Netherlands)

    Genceli, F.E.

    2008-01-01

    A novel crystallization technology, Eutectic Freeze Crystallization (EFC) has been investigated and further developed in this thesis work. EFC operates around the eutectic temperature and composition of aqueous solutions and can be used for recovery of (valuable) dissolved salts (and/or or acids)

  13. Development of Three-Layer Simulation Model for Freezing Process of Food Solution Systems

    Science.gov (United States)

    Kaminishi, Koji; Araki, Tetsuya; Shirakashi, Ryo; Ueno, Shigeaki; Sagara, Yasuyuki

    A numerical model has been developed for simulating freezing phenomena of food solution systems. The cell model was simplified to apply to food solution systems, incorporating with the existence of 3 parts such as unfrozen, frozen and moving boundary layers. Moreover, the moving rate of freezing front model was also introduced and calculated by using the variable space network method proposed by Murray and Landis (1957). To demonstrate the validity of the model, it was applied to the freezing processes of coffee solutions. Since the model required the phase diagram of the material to be frozen, the initial freezing temperatures of 1-55 % coffee solutions were measured by the DSC method. The effective thermal conductivity for coffee solutions was determined as a function of temperature and solute concentration by using the Maxwell - Eucken model. One-dimensional freezing process of 10 % coffee solution was simulated based on its phase diagram and thermo-physical properties. The results were good agreement with the experimental data and then showed that the model could accurately describe the change in the location of the freezing front and the distributions of temperature as well as ice fraction during a freezing process.

  14. A Case of Apparent Upper-Body Freezing in Parkinsonism while Using a Wheelchair

    Directory of Open Access Journals (Sweden)

    Samuel T. Nemanich

    2017-05-01

    Full Text Available Freezing of gait (FOG is a common, disabling gait disturbance in Parkinson’s disease (PD and other Parkinsonian syndromes. Freezing also occurs during non-gait movements involving the upper limbs. The mechanisms underlying freezing are complex, likely involving motor, cognitive, and sensory systems that contribute to the episodes. Here, we reported a 60-year-old female with a 24-year history of parkinsonism who experienced significant FOG when ambulatory. Disease progression resulted in her permanent use of a powered wheelchair. While using the power chair, the patient experiences apparent paroxysmal freezing in the hand and arm used to steer and propel the chair. These episodes, some lasting up to several minutes, occur only in circumstances (e.g., entering and leaving an elevator that are similar to environments known to elicit and exacerbate FOG. Episodes are transient and can be volitionally interrupted by the patient but sometimes require external assistance. Therapeutic intervention for this type of potential freezing has yet to be determined. This case may provide insight into the complex nature of freezing behavior and suggests a need for new approaches to treating non-traditional freezing behavior.

  15. Isolation of mutations affecting the development of freezing tolerance in Arabidopsis thaliana (L.) Heynh.

    Science.gov (United States)

    Warren, G; McKown, R; Marin, A L; Teutonico, R

    1996-08-01

    We screened for mutations deleterious to the freezing tolerance of Arabidopsis thaliana (L.) Heynh. ecotype Columbia. Tolerance was assayed by the vigor and regrowth of intact plants after cold acclimation and freezing. From a chemically mutagenized population, we obtained 13 lines of mutants with highly penetrant phenotypes. In 5 of these, freezing sensitivity was attributable to chilling injury sustained during cold acclimation, but in the remaining 8 lines, the absence of injury prior to freezing suggested that they were affected specifically in the development of freezing tolerance. In backcrosses, freezing sensitivity from each line segregated as a single nuclear mutation. Complementation tests indicated that the 8 lines contained mutations in 7 different genes. The mutants' freezing sensitivity was also detectable in the leakage of electrolytes from frozen leaves. However, 1 mutant line that displayed a strong phenotype at the whole-plant level showed a relatively weak phenotype by the electrolyte leakage assay.

  16. The interaction between freezing tolerance and phenology in temperate deciduous trees

    Directory of Open Access Journals (Sweden)

    Yann eVitasse

    2014-10-01

    Full Text Available Temperate climates are defined by a distinct temperature seasonality with large and often unpredictable weather during any of the four seasons. To thrive in such climates, trees have to withstand a cold winter and the stochastic occurrence of freeze events during any time of the year. The physiological mechanisms trees adopt to escape, avoid and tolerate freezing temperatures include a cold acclimation in autumn, a dormancy period during winter (leafless in deciduous trees, and the maintenance of a certain freezing tolerance during dehardening in early spring. The change from one phase to the next is mediated by complex interactions between temperature and photoperiod. This review aims at providing an overview of the interplay between phenology of leaves and species-specific freezing resistance. First, we address the long-term evolutionary responses that enabled temperate trees to tolerate certain low temperature extremes. We provide evidence that short term acclimation of freezing resistance plays a crucial role both in dormant and active buds, including re-acclimation to cold conditions following warm spells. This ability declines to almost zero during leaf emergence. Second, we show that the risk that native temperate trees encounter freeze injuries is low and is confined to spring and underline that this risk might be altered by climate warming depending on species-specific phenological responses to environmental cues.

  17. Analyse of relationships between freezing point and selected indicators of udder health state among cow, goat and sheep milk

    Directory of Open Access Journals (Sweden)

    Oto Hanuš

    2009-01-01

    Full Text Available Milk freezing point (MFP is important quality indicator. Aim was to analyse the relationships of MFP to selected udder health milk indicators (MIs by comparison between cows (reference, goats and sheep. Bulk milk samples came from 3 herds of Czech Fleckvieh (B, n 93 and 1 goat herd and sheep flock (White short-haired, W, n 60; Tsigai, C, n 60. Animal nutrition was performed under the typical country conditions. MIs which were investigated: DM, dry matter; SNF, solid non fat; L, lactose (all in %; SCC, somatic cell count (103 ml−1; EC, electrical conductivity (mS cm−1; MFP (°C; Na and K (in mg kg−1. W MFP was −0.5544 ± 0.0293, B −0.5221 ± 0.0043 and C −0.6048 ± 0.0691 °C. The B MFP was related to L (−0.36; P < 0.01, W was not related to L (−0.07; P > 0.05 and C was related to L (0.40; P < 0.01. These facts could be explainable by worse SCC geometric averages for used W (3,646 103 ml−1 and C (560 103 ml−1 milk as compared to B (159 103 ml−1. Only 0.5 and 10.5% of variations in MFP were explainable by variations in DM and SNF in B, 32.7 and 12.8% in W but already 49.4 and 45.0% in C. Higher C values were caused by high MFP variability, 11.8% (C versus 0.8% (B. There is possible to derive the more reliable MFP qualitative limits for more efficient monitoring rules of milk quality problems in B, W and C.

  18. Cell growth and resistance of Lactococcus lactis subsp. lactis TOMSC161 following freezing, drying and freeze-dried storage are differentially affected by fermentation conditions.

    Science.gov (United States)

    Velly, H; Fonseca, F; Passot, S; Delacroix-Buchet, A; Bouix, M

    2014-09-01

    To investigate the effects of fermentation parameters on the cell growth and on the resistance to each step of the freeze-drying process of Lactococcus lactis subsp. lactis TOMSC161, a natural cheese isolate, using a response surface methodology. Cells were cultivated at different temperatures (22, 30 and 38°C) and pH (5·6, 6·2 and 6·8) and were harvested at different growth phases (0, 3 and 6 h of stationary phase). Cultivability and acidification activity losses of Lc. lactis were quantified after freezing, drying, 1 and 3 months of storage at 4 and 25°C. Lactococcus lactis was not damaged by freezing but was sensitive to drying and to ambient temperature storage. Moreover, the fermentation temperature and the harvesting time influenced the drying resistance of Lc. lactis. Lactococcus lactis cells grown in a whey-based medium at 32°C, pH 6·2 and harvested at late stationary phase exhibited both an optimal growth and the highest resistance to freeze-drying and storage. A better insight on the individual and interaction effects of fermentation parameters made it possible the freeze-drying and storage preservation of a sensitive strain of technological interest. Evidence on the particularly damaging effect of the drying step and the high-temperature storage is presented. © 2014 The Society for Applied Microbiology.

  19. The Effect of Freezing and Hydrocolloids on the Physical Parameters of Strawberry Mass-Based Desserts

    Directory of Open Access Journals (Sweden)

    Boča Sigita

    2014-07-01

    Full Text Available The aim of the study was to evaluate the effect of freezing, thickening and storage on the physical properties of the strawberry desserts made with addition of various hydrocolloids. The strawberry cultivars ‘Polka’, ‘Honeoye’, and ‘Senga Sengana’ harvested in Latvia were used in the study. The strawberries were processed in a blender for obtaining a homogenous mass. The strawberry mass was analyzed fresh and after storage at -18 °C. Both fresh and frozen strawberry mass samples with added gelatine, xanthan gum, and sodium carboxymethyl cellulose were whisked until obtaining dessert. For determination of the optimum hydrocolloid amount, sensory evaluation was done using a five-point hedonic scale. Moisture, soluble solids content, density, and pH of the product were determined. Apparent viscosity was measured using a rotational viscometer DV–III Ultra. Consistency of the dessert during its storage was evaluated using a texture analyser TA.XT.plus. The results of sensory evaluation allow concluding that in order to provide the most acceptable consistency, colour, and taste of strawberry dessert, the optimum quantity of carboxymethyl cellulose and xanthan gum to be added is 0.6% and that of gelatine is 6%. During freezing, the soluble solids content and pH level decreased in the strawberry mass, whereas the addition of hydrocolloids increased these values. The moisture content in strawberry puree, in its turn, as a result of freezing increased under the influence of syneresis, but added hydrocolloids, on the contrary, decreased this influence. Also the viscosity and consistency of the strawberry puree prepared from the researched cultivars decreased under the influence of freezing, whereas the addition of hydrocolloids increased both the values, making the strawberry dessert firmer. The research suggests that strawberry dessert with gelatine had the most pronounced changes during storage, but strawberry dessert with added xanthan

  20. 9 CFR 354.244 - Temperatures and cooling and freezing procedures.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Temperatures and cooling and freezing procedures. 354.244 Section 354.244 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE... and cooling and freezing procedures. Temperatures and procedures which are necessary for cooling and...

  1. A new dispersive liquid-liquid microextraction using ionic liquid based microemulsion coupled with cloud point extraction for determination of copper in serum and water samples.

    Science.gov (United States)

    Arain, Salma Aslam; Kazi, Tasneem Gul; Afridi, Hassan Imran; Arain, Mariam Shahzadi; Panhwar, Abdul Haleem; Khan, Naeemullah; Baig, Jameel Ahmed; Shah, Faheem

    2016-04-01

    A simple and rapid dispersive liquid-liquid microextraction procedure based on ionic liquid assisted microemulsion (IL-µE-DLLME) combined with cloud point extraction has been developed for preconcentration copper (Cu(2+)) in drinking water and serum samples of adolescent female hepatitits C (HCV) patients. In this method a ternary system was developed to form microemulsion (µE) by phase inversion method (PIM), using ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim][PF6]) and nonionic surfactant, TX-100 (as a stabilizer in aqueous media). The Ionic liquid microemulsion (IL-µE) was evaluated through visual assessment, optical light microscope and spectrophotometrically. The Cu(2+) in real water and aqueous acid digested serum samples were complexed with 8-hydroxyquinoline (oxine) and extracted into IL-µE medium. The phase separation of stable IL-µE was carried out by the micellar cloud point extraction approach. The influence of of different parameters such as pH, oxine concentration, centrifugation time and rate were investigated. At optimized experimental conditions, the limit of detection and enhancement factor were found to be 0.132 µg/L and 70 respectively, with relative standard deviation <5%. In order to validate the developed method, certified reference materials (SLRS-4 Riverine water) and human serum (Sero-M10181) were analyzed. The resulting data indicated a non-significant difference in obtained and certified values of Cu(2+). The developed procedure was successfully applied for the preconcentration and determination of trace levels of Cu(2+) in environmental and biological samples. Copyright © 2015 Elsevier Inc. All rights reserved.

  2. Freeze-casting: Fabrication of highly porous and hierarchical ceramic supports for energy applications

    Directory of Open Access Journals (Sweden)

    Cyril Gaudillere

    2016-03-01

    The aim of this paper is to give an overview of the freeze-casting ceramic shaping method and to show how its implementation could be useful for several energy applications where key components comprise a porous scaffold. A detailed presentation of the freeze-casting process and of the characteristics of the resulting porous parts is firstly given. The characteristic of freeze-cast parts and the drawbacks of conventional porous scaffolds existing in energy applications are drawn in order to highlight the expected beneficial effect of this new shaping technique as possible substitute to the conventional ones. Finally, a review of the state of the art freeze-cast based energy applications developed up to now and expected to be promising is given to illustrate the large perspectives opened by the implementation of the freeze-casting of ceramics for energy fields. Here we suggest discussing about the feasibility of incorporate freeze-cast porous support in high temperature ceramic-based energy applications.

  3. Deep freezing of cattle embryos in glass ampules or French straws.

    Science.gov (United States)

    Massip, A; Van der Zwalmen, P; Ectors, F; De Coster, R; D'Ieteren, G; Hanzen, C

    1979-08-01

    Ninety four cow embryos recovered on day 7-8 after onset of oestrus were frozen by the "Two Step" freezing procedure: 49 in pyrex glass ampules and 45 in .25 ml French semen straws. The overall survival rate was 33.7% (36.2% for embryos frozen in glass ampules; 31.1% for embryos frozen in plastic straws). 45.2% of transferred embryos resulted in pregnancies (35.7% after freezing in glass ampules v.s 52.9% after freezing in plastic straws).

  4. Limited Impact of Subglacial Supercooling Freeze-on for Greenland Ice Sheet Stratigraphy

    Science.gov (United States)

    Dow, Christine F.; Karlsson, Nanna B.; Werder, Mauro A.

    2018-02-01

    Large units of disrupted radiostratigraphy (UDR) are visible in many radio-echo sounding data sets from the Greenland Ice Sheet. This study investigates whether supercooling freeze-on rates at the bed can cause the observed UDR. We use a subglacial hydrology model to calculate both freezing and melting rates at the base of the ice sheet in a distributed sheet and within basal channels. We find that while supercooling freeze-on is a phenomenon that occurs in many areas of the ice sheet, there is no discernible correlation with the occurrence of UDR. The supercooling freeze-on rates are so low that it would require tens of thousands of years with minimal downstream ice motion to form the hundreds of meters of disrupted radiostratigraphy. Overall, the melt rates at the base of the ice sheet greatly overwhelm the freeze-on rates, which has implications for mass balance calculations of Greenland ice.

  5. Freeze-drying of mononuclear cells derived from umbilical cord blood followed by colony formation.

    Directory of Open Access Journals (Sweden)

    Dity Natan

    Full Text Available BACKGROUND: We recently showed that freeze-dried cells stored for 3 years at room temperature can direct embryonic development following cloning. However, viability, as evaluated by membrane integrity of the cells after freeze-drying, was very low; and it was mainly the DNA integrity that was preserved. In the present study, we improved the cells' viability and functionality after freeze-drying. METHODOLOGY/PRINCIPAL FINDINGS: We optimized the conditions of directional freezing, i.e. interface velocity and cell concentration, and we added the antioxidant EGCG to the freezing solution. The study was performed on mononuclear cells (MNCs derived from human umbilical cord blood. After freeze-drying, we tested the viability, number of CD34(+-presenting cells and ability of the rehydrated hematopoietic stem cells to differentiate into different blood cells in culture. The viability of the MNCs after freeze-drying and rehydration with pure water was 88%-91%. The total number of CD34(+-presenting cells and the number of colonies did not change significantly when evaluated before freezing, after freeze-thawing, and after freeze-drying (5.4 x 10(4+/-4.7, 3.49 x 10(4+/-6 and 6.31 x 10(4+/-12.27 cells, respectively, and 31+/-25.15, 47+/-45.8 and 23.44+/-13.3 colonies, respectively. CONCLUSIONS: This is the first report of nucleated cells which have been dried and then rehydrated with double-distilled water remaining viable, and of hematopoietic stem cells retaining their ability to differentiate into different blood cells.

  6. Freeze-all cycle in reproductive medicine: current perspectives.

    Science.gov (United States)

    Roque, Matheus; Valle, Marcello; Kostolias, Alessandra; Sampaio, Marcos; Geber, Selmo

    2017-02-01

    The freeze-all strategy has emerged as an alternative to fresh embryo transfer (ET) during in vitro fertilization (IVF) cycles. Although fresh ET is the norm during assisted reproductive therapies (ART), there are many concerns about the possible adverse effects of controlled ovarian stimulation (COS) over the endometrium. The supra-physiologic hormonal levels that occur during a conventional COS are associated with modifications in the peri-implantation endometrium, which may be related to a decrease in pregnancy rates and poorer obstetric and perinatal outcomes when comparing fresh to frozen-thawed embryo transfers. The main objective of this study was to assess the available literature regarding the freeze-all strategy in IVF cycles, in regards to effectiveness and safety. Although there are many potential advantages in performing a freeze-all cycle over a fresh ET, it seems that the freeze-all strategy is not designed for all IVF patients. There is a need to develop a non-invasive clinical tool to evaluate the endometrial receptivity during a fresh cycle, which enables the selection of patients that would benefit from this strategy. Today, it is reasonable to perform elective cryopreservation of all oocytes/embryos in cases with a risk of OHSS development, and in patients with supra-physiologic hormonal levels during the follicular phase of COS. It is not clear if all normal responders and poor responders may benefit from this strategy.

  7. Asymptotic freeze-out of the perturbations generated inside a corrugated rarefaction wave

    International Nuclear Information System (INIS)

    Wouchuk, J.G.; Serrano Rodrigo, A.D.

    2004-01-01

    Based on previous work [J. G. Wouchuk and R. Carretero, Phys. Plasmas 10, 4237 (2003)], the conditions of asymptotic freeze-out of the ripples at the tail of a corrugated rarefaction wave are analyzed. The precise location of the freezing-out regions in the space of preshock parameters is tried, and an efficient algorithm for their determination is given. It is seen that asymptotic freeze-out can only happen for gases that have an isentropic exponent γ cr ≅2.2913hellip. It is shown that the late time freeze-out of the ripple perturbations is correlated to the initial tangential velocity profile (at t=0+) inside the expansion fan

  8. The freezing of water bonded in the wheat (Triticum aestivum L.) grain studied by means protons magnetic relaxation method; Zamarzanie wody zwiazanej w ziarnach pszenicy (Triticum aestivum L.) badane metoda relaksacji magnetycznej dla protonow

    Energy Technology Data Exchange (ETDEWEB)

    Haranczyk, H.; Jasinski, G. [Inst. Fizyki, Uniwersytet Jagiellonski, Cracow (Poland); Strzalka, K. [Inst. Biologii Molekularnej, Uniwersytet Jagiellonski, Cracow (Poland)

    1994-12-31

    Some biological aspects of water freezing in the wheat grain have been studied using NMR methods. Measuring of the relaxation times for freezing and liquid water shown absence of T{sub 2}{approx}100 {mu}s and T{sub 2}{approx}1 ms separated components what pointed for some different way of water bonding. 7 refs, 12 figs, 2 tabs.

  9. FREEZING AND THAWING TIME PREDICTION METHODS OF FOODS II: NUMARICAL METHODS

    Directory of Open Access Journals (Sweden)

    Yahya TÜLEK

    1999-03-01

    Full Text Available Freezing is one of the excellent methods for the preservation of foods. If freezing and thawing processes and frozen storage method are carried out correctly, the original characteristics of the foods can remain almost unchanged over an extended periods of time. It is very important to determine the freezing and thawing time period of the foods, as they strongly influence the both quality of food material and process productivity and the economy. For developing a simple and effectively usable mathematical model, less amount of process parameters and physical properties should be enrolled in calculations. But it is a difficult to have all of these in one prediction method. For this reason, various freezing and thawing time prediction methods were proposed in literature and research studies have been going on.

  10. Sperm preservation by freeze-drying for the conservation of wild animals.

    Directory of Open Access Journals (Sweden)

    Takehito Kaneko

    Full Text Available Sperm preservation is a useful technique for the maintenance of biological resources in experimental and domestic animals, and in wild animals. A new preservation method has been developed that enables sperm to be stored for a long time in a refrigerator at 4 °C. Sperm are freeze-dried in a solution containing 10 mM Tris and 1 mM EDTA. Using this method, liquid nitrogen is not required for the storage and transportation of sperm. We demonstrate that chimpanzee, giraffe, jaguar, weasel and the long-haired rat sperm remain viable after freeze-drying. In all species, pronuclei were formed after the injection of freeze-dried sperm into the mouse oocytes. Although preliminary, these results may be useful for the future establishment of "freeze-drying zoo" to conserve wild animals.

  11. Freezing and refrigerated storage in fisheries

    National Research Council Canada - National Science Library

    Johnston, W. A

    1994-01-01

    ...; the factors affecting cold storage conditions, etc. In addition, the publication describes the methods used to calculate cold storage refrigeration loads as well as the costs of freezing and cold storage...

  12. 9 CFR 381.66 - Temperatures and chilling and freezing procedures.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Temperatures and chilling and freezing procedures. 381.66 Section 381.66 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT... Procedures § 381.66 Temperatures and chilling and freezing procedures. (a) General. Temperatures and...

  13. Study on irradiaiton of freezing-dried Wuchang fish

    International Nuclear Information System (INIS)

    Chen Xueling; Cheng Wei; Xiong Guangquan; Ye Lixiu; Chen Yuxia; Guan Jian; He Jianjun

    2008-01-01

    The effects of irradiation on sterilization and storage time for the freezing-dried Wuchang fish were studied. The results show that the number of the coliform group in freezing-dried Wuchang fish irradiated at 1kGy can be acceptable according to the national industrial standard and the number of bacteria decrease from 3100cfu/g to <10cfu/g after irradiation. With the optimal irradiation dose 1kGy the shelf life of Wuchang fish can be extended over one year. (authors)

  14. Social Freezing in Medical Practice. Experiences and Attitudes of Gynecologists in Germany.

    Science.gov (United States)

    Schochow, Maximilian; Rubeis, Giovanni; Büchner-Mögling, Grit; Fries, Hansjakob; Steger, Florian

    2017-09-09

    Surveys of the German public have revealed a high acceptance of social freezing, i.e. oocyte conservation without medical indication. Up to now, there are no investigations available on the experiences and attitudes of health professionals towards social freezing. Between August 2015 and January 2016, we surveyed gynecologists Germany-wide on the topic social freezing. Five gynecologists specialized in reproductive medicine and five office-based gynecologists in standard care were chosen for the survey. The survey was conducted with an explorative, qualitative research design. The demand for social freezing in Germany is low. With regard to their fertility age, most women attend consultations too late, they have only little previous knowledge and false expectations. The gynecologists consider it the duty of society and politics to provide for the compatibility of family and work. They relate late parenthood to disadvantages primarily for the children. A majority of the gynecologists interviewed tend to advise natural reproduction. Social freezing is often mistaken as a kind of fertility insurance. Thus, it is necessary that physicians inform women early about the possibilities and limitations of social freezing. In the first place, social freezing is not a medical or medical-ethical topic. Women consider the method as a possibility to ensure the compatibility of family and work. This compatibility should be mostly perceived as a political topic. It cannot be a medical task to solve this issue. In fact, a debate in society as a whole is necessary that includes all relevant actors.

  15. Application of two electrical methods for the rapid assessment of freezing resistance in Salix epichloro

    Energy Technology Data Exchange (ETDEWEB)

    Tsarouhas, V.; Kenney, W.A.; Zsuffa, L. [University of Toronto, Ontario (Canada). Faculty of Forestry

    2000-09-01

    The importance of early selection of frost-resistant Salix clones makes it desirable to select a rapid and accurate screening method for assessing freezing resistance among several genotypes. Two electrical methods, stem electrical impedance to 1 and 10 khz alternating current, and electrolyte leakage of leaf tissue, were evaluated for detecting freezing resistance on three North America Salix epichloro Michx., clones after subjecting them to five different freezing temperatures (-1, -2, -3, -4, and -5 deg C). Differences in the electrical impedance to 1 and 10 kHz, and the ratio of the impedance at the two frequencies (low/high) before and after the freezing treatment (DZ{sub low}, DZ{sub high}, and DZ{sub ratio}, respectively) were estimated. Electrolyte leakage was expressed as relative conductivity (RC{sub t}) and index of injury (IDX{sub t}). Results from the two methods, obtained two days after the freezing stress, showed that both electrical methods were able to detect freezing injury in S. eriocephala. However, the electrolyte leakage method detected injury in more levels of freezing stress (-3, -4, and -5 deg C) than the impedance (-4, and -5 deg C), it assessed clonal differences in S. eriocephala freezing resistance, and it was best suited to correlate electrical methods with the visual assessed freezing injury. No significant impedance or leakage changes were found after the -1 and -2 deg C freezing temperatures. (author)

  16. Effect of freeze-thaw cycles on greenhouse gas fluxes from peat soils

    Science.gov (United States)

    Oh, H. D.; Rezanezhad, F.; Markelov, I.; McCarter, C. P. R.; Van Cappellen, P.

    2017-12-01

    The ongoing displacement of climate zones by global warming is increasing the frequency and intensity of freeze-thaw cycles in middle and high latitude regions, many of which are dominated by organic soils such as peat. Repeated freezing and thawing of soils changes their physical properties, geochemistry, and microbial community structure, which together govern the biogeochemical cycling of carbon and nutrients. In this presentation, we focus on how freeze-thaw cycles influence greenhouse gas fluxes from peat using a newly developed experimental soil column system that simulates realistic soil temperature profiles during freeze-thaw cycles. We measured the surface and subsurface changes to gas and aqueous phase chemistry to delineate the diffusion pathways and quantify soil greenhouse gas fluxes during freeze-thaw cycles using sulfur hexafluoride (SF6) as a conservative tracer. Three peat columns were assembled inside a temperature controlled chamber with different soil structures. All three columns were packed with 40 cm of undisturbed, slightly decomposed peat, where the soil of two columns had an additional 10 cm layer on top (one with loose Sphagnum moss and one with an impermeable plug). The results indicate that the release of SF6 and CO2 gas from the soil surface was influenced by the recurrent development of a physical ice barrier, which prevented gas exchange between the soil and atmosphere during freezing conditions. With the onset of thawing a pulse of SF6 and CO2 occurred, resulting in a flux of 3.24 and 2095.52 µmol/m2h, respectively, due to the build-up of gases in the liquid-phase pore space during freezing. Additionally, we developed a model to determine the specific diffusion coefficients for each peat column. These data allow us to better predict how increased frequency and intensity of freeze-thaw cycles will affect greenhouse gas emissions in northern peat soils.

  17. Prediction of frozen food properties during freezing using product composition.

    Science.gov (United States)

    Boonsupthip, W; Heldman, D R

    2007-06-01

    Frozen water fraction (FWF), as a function of temperature, is an important parameter for use in the design of food freezing processes. An FWF-prediction model, based on concentrations and molecular weights of specific product components, has been developed. Published food composition data were used to determine the identity and composition of key components. The model proposed in this investigation had been verified using published experimental FWF data and initial freezing temperature data, and by comparison to outputs from previously published models. It was found that specific food components with significant influence on freezing temperature depression of food products included low molecular weight water-soluble compounds with molality of 50 micromol per 100 g food or higher. Based on an analysis of 200 high-moisture food products, nearly 45% of the experimental initial freezing temperature data were within an absolute difference (AD) of +/- 0.15 degrees C and standard error (SE) of +/- 0.65 degrees C when compared to values predicted by the proposed model. The predicted relationship between temperature and FWF for all analyzed food products provided close agreements with experimental data (+/- 0.06 SE). The proposed model provided similar prediction capability for high- and intermediate-moisture food products. In addition, the proposed model provided statistically better prediction of initial freezing temperature and FWF than previous published models.

  18. Statistics of structural holes in the one-component classical plasma near freezing

    International Nuclear Information System (INIS)

    Cardenas, M.; Tosi, M.P.

    1998-03-01

    The correlations between structural holes in the fluid phase of the one-component classical plasma near its freezing point at coupling strength Γ=179 are studied by a statistical method using the Ornstein-Zernike relations for a partly quenched disordered system in combination with the hypernetted chain closure. The method involves inserting in the quenched structure of the plasma variable numbers of point-like charged particles, which on reaching equilibrium probe the holes in the matrix. When the probes carry the same charge as the plasma particles, the results may also be interpreted as describing the evolution of the correlations between annealed particles in a partly quenched disordered plasma upon varying the fraction of quenched particles at constant total density. Doubling the charge carried by the probes sharpens their correlations and improves the resolution that can be obtained in this method of structural analysis. (author)

  19. Effec t of Freeze-Thaw Cycles on Lipid Oxidation and Myowater in Broiler Chickens

    Directory of Open Access Journals (Sweden)

    S Ali

    2016-03-01

    Full Text Available ABSTRACT The present study was carried out to investigate the influence of freezing-thawing cycles (0, 2, 4 and 6 on lipid oxidation and myowater contents and distribution. Nine replicates of chicken breast meat samples were used for each cycle. Lipid oxidation was determined by measuring peroxide value, and malondialdehyde (MDA concentrations, which reflect thiobarbituric acid reactive substance (TBARS. Color was determined with a digital colorimeter. Muscle moisture contents were determined by drip loss and thawing loss, water holding capacity, and nuclear magnetic resonance (NMR. The results showed that, as the number of freeze-thaw cycles increased, meat redness decreased and MDA and peroxide values increased. Drip loss and thawing loss tended to decreasing as the number of freeze-thaw cycles increased. Water holding capacity also decreased as a function of increasing freeze-thaw cycles. NMR relaxometry profile showed freeze-thaw cycles change the water distribution of meat subjected to multiple freeze-thaw cycles. In conclusion, multiple freezing and thawing rate (6 cycles increased lipid oxidation, decreased myowater, and impaired the color of chicken meat.

  20. Immersion and contact freezing experiments in the Mainz wind tunnel laboratory

    Science.gov (United States)

    Eppers, Oliver; Mayer, Amelie; Diehl, Karoline; Mitra, Subir; Borrmann, Stephan; Szakáll, Miklós

    2016-04-01

    Immersion and contact freezing are of outmost important ice nucleation processes in mixed phase clouds. Experimental studies are carried out in the Mainz vertical wind tunnel laboratory in order to characterize these nucleation processes for different ice nucleating particles (INP), such as for mineral dust or biological particles. Immersion freezing is investigated in our laboratory with two different experimental techniques, both attaining contact-free levitation of liquid droplets and cooling of the surrounding air down to about -25 °C. In an acoustic levitator placed in the cold room of our laboratory, drops with diameters of 2 mm are investigated. In the vertical air stream of the wind tunnel droplets with diameter of 700 micron are freely floated at their terminal velocities, simulating the flow conditions of the free atmosphere. Furthermore, the wind tunnel offers a unique platform for contact freezing experiments. Supercooled water droplets are floated in the vertical air stream at their terminal velocities and INP are injected into the tunnel air stream upstream of them. As soon as INP collides with the supercooled droplet the contact freezing is initiated. The first results of immersion and contact freezing experiments with cellulose particles both in the acoustic levitator and in the wind tunnel will be presented. Cellulose is considered as typical INP of biological origin and a macrotracer for plant debris. Nucleating properties of cellulose will be provided, mainly focusing on the temperature, INP concentration, and specific surface area dependences of the freezing processes. Direct comparison between the different experimental techniques (acoustic levitator and wind tunnel), as well as between nucleation modes (immersion and contact freezing) will be presented. The work is carried out within the framework of the German research unit INUIT.

  1. Lesions causing freezing of gait localize to a cerebellar functional network

    Science.gov (United States)

    Fasano, Alfonso; Laganiere, Simon E.; Lam, Susy; Fox, Michael D.

    2016-01-01

    Objective Freezing of gait is a disabling symptom in Parkinson’s disease and related disorders, but the brain regions involved in symptom generation remain unclear. Here we analyze brain lesions causing acute onset freezing of gait to identify regions causally involved in symptom generation. Methods Fourteen cases of lesion-induced freezing of gait were identified from the literature and lesions were mapped to a common brain atlas. Because lesion-induced symptoms can come from sites connected to the lesion location, not just the lesion location itself, we also identified brain regions functionally connected to each lesion location. This technique, termed lesion network mapping, has been recently shown to identify regions involved in symptom generation across a variety of lesion-induced disorders. Results Lesion location was heterogeneous and no single region could be considered necessary for symptom generation. However, over 90% (13/14) of lesions were functionally connected to a focal area in the dorsal medial cerebellum. This cerebellar area overlapped previously recognized regions that are activated by locomotor tasks, termed the cerebellar locomotor region. Connectivity to this region was specific to lesions causing freezing of gait compared to lesions causing other movement disorders (hemichorea or asterixis). Interpretation Lesions causing freezing of gait are located within a common functional network characterized by connectivity to the cerebellar locomotor region. These results based on causal brain lesions complement prior neuroimaging studies in Parkinson’s disease patients, advancing our understanding of the brain regions involved in freezing of gait. PMID:28009063

  2. Running out of time: exploring women's motivations for social egg freezing.

    Science.gov (United States)

    Baldwin, Kylie; Culley, Lorraine; Hudson, Nicky; Mitchell, Helene

    2018-04-12

    Few qualitative studies have explored women's use of social egg freezing. Derived from an interview study of 31 participants, this article explores the motivations of women using this technology. Semi-structured interviews were conducted with 31 users of social egg freezing resident in UK (n = 23), USA (n = 7) and Norway (n = 1). Interviews were face to face (n = 16), through Skype and Facetime (n = 9) or by telephone (n = 6). Data were analyzed using interpretive thematic analysis. Women's use of egg freezing was shaped by fears of running out of time to form a conventional family, difficulties in finding a partner and concerns about "panic partnering", together with a desire to avoid future regrets and blame. For some women, use of egg freezing was influenced by recent fertility or health diagnoses as well as critical life events. A fifth of the participants also disclosed an underlying fertility or health issue as affecting their decision. The study provides new insights in to the complex motivations women have for banking eggs. It identifies how women's use of egg freezing was an attempt to "preserve fertility" in the absence of the particular set of "life conditions" they regarded as crucial for pursuing parenthood. It also demonstrates that few women were motivated by a desire to enhance their career and that the boundaries between egg freezing for medical and for social reasons may be more porous than first anticipated.

  3. Effect of food additives on egg yolk gelation induced by freezing.

    Science.gov (United States)

    Primacella, Monica; Fei, Tao; Acevedo, Nuria; Wang, Tong

    2018-10-15

    This study demonstrates technological advances in preventing yolk gelation during freezing and thawing. Gelation negatively affects yolk functionality in food formulation. Preventing gelation using 10% salt or sugar limits the application of the yolk. Novel food additives were tested to prevent gelation induced by freezing. Significant reduction (p freezing at -20 °C) indicates that hydrolyzed carboxymethyl cellulose (HCMC), proline, and hydrolyzed egg white and yolk (HEW and HEY) are effective gelation inhibitors. The mechanisms in which these additives prevented gelation were further studied through measuring the changes in the amount of freezable water, lipoprotein particle size, and protein surface hydrophobicity. Overall, this study provides several alternatives of gelation inhibitor that have great potentials in replacing the use of salt or sugar in commercial operation of freezing egg yolk for shelf-life extension. Copyright © 2018 Elsevier Ltd. All rights reserved.

  4. Infant attachment predicts bodily freezing in adolescence: evidence from a prospective longitudinal study

    Directory of Open Access Journals (Sweden)

    Hannah C. M. Niermann

    2015-10-01

    Full Text Available Early life-stress, particularly maternal deprivation, is associated with long-lasting deviations in animals’ freezing responses. Given the relevance of freezing for stress-coping, translational research is needed to examine the relation between insecure infant-parent attachment and bodily freezing-like behavior in humans. Therefore, we investigated threat-related reductions in body sway (indicative of freezing-like behavior in 14-year-old adolescents (N=79, for whom attachment security was earlier assessed in infancy. As expected, insecure (versus secure attachment was associated with less body sway for angry versus neutral faces. This effect remained when controlling for intermediate life-events. These results suggest that the long-lasting effects of early negative caregiving experiences on the human stress and threat systems extend to the primary defensive reaction of freezing. Additionally, we replicated earlier work in adults, by observing a significant correlation (in adolescents assessed as securely attached between subjective state anxiety and reduced body sway in response to angry versus neutral faces. Together, this research opens venues to start exploring the role of freezing in the development of human psychopathology.

  5. Reduced freezing in posttraumatic stress disorder patients while watching affective pictures

    NARCIS (Netherlands)

    Fragkaki, Iro; Roelofs, Karin; Stins, John; Jongedijk, Ruud A.; Hagenaars, Muriel A.

    2017-01-01

    Besides fight and flight responses, animals and humans may respond to threat with freezing, a response characterized by bradycardia and physical immobility. Risk assessment is proposed to be enhanced during freezing to promote optimal decision making. Indeed, healthy participants showed

  6. Reduced freezing in posttraumatic stress disorder patients while watching affective pictures

    NARCIS (Netherlands)

    Fragkaki, Iro; Roelofs, Karin; Stins, John; Jongedijk, Ruud A.; Hagenaars, Muriel A.

    Besides fight and flight responses, animals and humans may respond to threat with freezing, a response characterized by bradycardia and physical immobility. Risk assessment is proposed to be enhanced during freezing to promote optimal decision making. Indeed, healthy participants showed

  7. Cortical correlates of susceptibility to upper limb freezing in Parkinson's disease

    NARCIS (Netherlands)

    Scholten, M.; Govindan, R.B.; Braun, C.; Bloem, B.R.; Plewnia, C.; Kruger, R.; Gharabaghi, A.; Weiss, D.

    2016-01-01

    OBJECTIVE: Freezing behavior is an unmet symptom in Parkinson's disease (PD), which reflects its complex pathophysiology. Freezing behavior can emerge when attentional capacity is reduced, i.e. under dual task interference. In this study, we characterized the cortical network signatures underlying

  8. The effect of dryer load on freeze drying process design.

    Science.gov (United States)

    Patel, Sajal M; Jameel, Feroz; Pikal, Michael J

    2010-10-01

    Freeze-drying using a partial load is a common occurrence during the early manufacturing stages when insufficient amounts of active pharmaceutical ingredient (API) are available. In such cases, the immediate production needs are met by performing lyophilization with less than a full freeze dryer load. However, it is not obvious at what fractional load significant deviations from full load behavior begin. The objective of this research was to systematically study the effects of variation in product load on freeze drying behavior in laboratory, pilot and clinical scale freeze-dryers. Experiments were conducted with 5% mannitol (high heat and mass flux) and 5% sucrose (low heat and mass flux) at different product loads (100%, 50%, 10%, and 2%). Product temperature was measured in edge as well as center vials with thermocouples. Specific surface area (SSA) was measured by BET gas adsorption analysis and residual moisture was measured by Karl Fischer. In the lab scale freeze-dryer, the molar flux of inert gas was determined by direct flow measurement using a flowmeter and the molar flux of water vapor was determined by manometric temperature measurement (MTM) and tunable diode laser absorption spectroscopy (TDLAS) techniques. Comparative pressure measurement (capacitance manometer vs. Pirani) was used to determine primary drying time. For both 5% mannitol and 5% sucrose, primary drying time decreases and product temperature increases as the load on the shelves decreases. No systematic variation was observed in residual moisture and vapor composition as load decreased. Further, SSA data suggests that there are no significant freezing differences under different load conditions. Independent of dryer scale, among all the effects, variation in radiation heat transfer from the chamber walls to the product seems to be the dominant effect resulting in shorter primary drying time as the load on the shelf decreases (i.e., the fraction of edge vials increases).

  9. Effect of freezing and thawing on UMTRA covers

    International Nuclear Information System (INIS)

    Rager, R.; Smith, G.; Brody, R.

    1988-01-01

    The proposed US Environmental Protection Agency (EPA) groundwater standards (40 CFR 192) require that Uranium Mill Tailings Remedial Action (UMTRA) Project remedial action designs meet low numerical limits for contaminants contained in water or vapor exiting the embankments. To meet the standards, a cover of compacted fine-grained soil is placed over UMTRA Project embankments. One of the functions of this cover is to limit infiltration. The hydraulic conductivity of this infiltration barrier must be low in order to reduce seepage from the cell to the extent necessary to comply with the proposed EPA groundwater standards. Analyses of infiltration barriers covered with rock erosion protection show that the infiltration barriers may become saturated. Accordingly, it is necessary to assure that freezing and thawing of the infiltration barrier materials do not affect the performance of the embankment. A study has been conducted to determine if the hydraulic conductivity of fine-grained clayey soils used or proposed for use in radon/infiltration barriers is affected by repeated freezing and thawing cycles. In addition, a procedure for determining the depth of frost penetration has been developed. Laboratory freeze-thaw tests were undertaken in order to determine if the saturated hydraulic conductivity of clay soils used in UMTRA Project radon/infiltration barriers was affected. The results indicate that an increase of an order of magnitude or more in saturated hydraulic conductivity may occur during repeated freeze-thaw cycles

  10. Chemical freeze out condition for central heavy-ion collisions at AGS, SPS, RHIC and LHC energies

    International Nuclear Information System (INIS)

    Chatterjee, Sandeep; Mishra, Debadeepti; Mohanty, Bedangadas; Das, Sabita; Sharma, Natasha; Kumar, Lokesh; Sahoo, Raghunath

    2014-01-01

    As a result of ultrarelativistic collision between two heavy ions, a fireball is expected to form that rapidly thermalized as it expands and hence cools. As the interparticle separation increases the particles cease to interact. The surface of last scattering is the freeze-out surface. It can be of two types: chemical freeze-out (CFO) where inelastic collisions cease and kinetic freeze-out where elastic collisions cease. But in general freeze-out can be a more complicated process in which different types of particles and reactions switch-off at different times giving rise to a series of freeze-out surfaces. Here we will discuss two CFO schemes: 1CFO, in which all hadrons freeze-out together and 2CFO, in which all strange and those with hidden strangeness freeze-out at the same surface and the other non strange hadrons freeze-out at a separate surface

  11. Development of freeze-dried miyeokguk, Korean seaweed soup, as space food sterilized by irradiation

    International Nuclear Information System (INIS)

    Song, Beom-Seok; Park, Jin-Gyu; Kim, Jae-Hun; Choi, Jong-Il; Ahn, Dong-Hyun; Hao, Chen; Lee, Ju-Woon

    2012-01-01

    The purpose of this study was to evaluate microbial populations, Hunter's color values (L ⁎ , a ⁎ , b ⁎ ) and the sensory quality of freeze-dried miyeokguk, Korean seaweed soup, in order to use it as space food. Microorganisms were not detected in non-irradiated freeze-dried miyeokguk within the detection limit of 1.00 log CFU/g. However, the microbial population in rehydrated miyeokguk was 7.01 log CFU/g after incubation at 35 °C for 48 h, indicating that freeze-dried miyeokguk was not sterilized by heat treatment during the preparation process. Bacteria in the freeze-dried miyeokguk were tentatively identified as Bacillus cereus, B. subtilis, Enterobacter hormaechei, and Ancinetobacter genomosp. using the 16S rDNA sequencing. In samples that were gamma-irradiated above 10 kGy, it was confirmed that all microorganisms were inactivated. Hunter's color values of the samples irradiated at doses less than 10 kGy were not significantly altered from their baseline appearance (p>0.05). Sensory evaluation showed that preference scores in all sensory properties decreased when freeze-dried miyeokguk was irradiated at doses greater than 10 kGy. Therefore, the results of this study suggest that gamma irradiation at 10 kGy is sufficient to sterilize freeze-dried miyeokguk without significant deterioration in the sensory quality, and thus, the freeze-dried and irradiated miyeokguk at 10 kGy fulfills the microbiological requirements as space food. - Highlights: ► 10 kGy gamma-irradiation is sufficient for sterilization of freeze-dried miyeokguk. ► Sensory quality of freeze-dried miyeokguk decreased after >10 kGy gamma irradiation. ► 10 kGy gamma-irradiation sterilizes freeze-dried miyeokguk and makes it optimal for use as space food.

  12. Investigation of the Behavior of the Co C Eutectic Fixed Point

    Science.gov (United States)

    Girard, F.; Battuello, M.; Florio, M.

    2007-12-01

    The behavior of the Co C eutectic fixed point was investigated at INRIM. Several cells of different design and volume, and filled with cobalt of different purity were constructed and investigated with both Pt/Pd thermocouples and radiation thermometers. The melting behavior was investigated with respect to the melting rate, the pre-freezing rate, and the annealing time. The melting temperatures, as defined, were not significantly affected by the different testing conditions, even if the shape and duration of the plateaux were influenced. Several tens of melt and freeze cycles were performed with the different cells. The spread in the results for all of the different conditions was very limited in extent, giving rise to a standard deviation of less than 0.04 °C; a repeatability of better than 0.02 °C was found with both Pt/Pd thermocouples and radiation thermometers. The results of our measurements are encouraging and confirm the suitability of Co C as a reference point for the high-temperature range in a possible future temperature scale. Investigations of long-term stability remain ongoing.

  13. Structure-property-processing correlations in freeze-cast composite scaffolds.

    Science.gov (United States)

    Hunger, Philipp M; Donius, Amalie E; Wegst, Ulrike G K

    2013-05-01

    Surprisingly few reports have been published, to date, on the structure-property-processing correlations observed in freeze-cast materials directionally solidified from polymer solutions, or ceramic or metal slurries. The studies that exist focus on properties of sintered ceramics, that is materials whose structure was altered by further processing. In this contribution, we report first results on correlations observed in alumina-chitosan-gelatin composites, which were chosen as a model system to test and compare the effect of particle size and processing parameters on their mechanical properties at a specific composition. Our study reveals that highly porous (>90%) hybrid materials can be manufactured by freeze casting, through the self-assembly of a polymer and a ceramic phase that occurs during directional solidification, without the need of additional processing steps such as sintering or infiltration. It further illustrates that the properties of freeze-cast hybrid materials can independently be tailored at two levels of their structural hierarchy, allowing for the simultaneous optimization of both mechanical and structural requirements. An increase in freezing rate resulted in decreases in lamellar spacing, cell wall thickness, pore aspect ratio and cross-sectional area, as well as increases in both Young's modulus and compressive yield strength. The mechanical properties of the composite scaffolds increased with an increasing particle size. The results show that both structure and mechanical properties of the freeze-cast composites can be custom-designed and that they are thus ideally suited for a large variety of applications that require high porosity at low or medium load-bearing capacity. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  14. High ice nucleation activity located in blueberry stem bark is linked to primary freeze initiation and adaptive freezing behaviour of the bark

    Science.gov (United States)

    Kishimoto, Tadashi; Yamazaki, Hideyuki; Saruwatari, Atsushi; Murakawa, Hiroki; Sekozawa, Yoshihiko; Kuchitsu, Kazuyuki; Price, William S.; Ishikawa, Masaya

    2014-01-01

    Controlled ice nucleation is an important mechanism in cold-hardy plant tissues for avoiding excessive supercooling of the protoplasm, for inducing extracellular freezing and/or for accommodating ice crystals in specific tissues. To understand its nature, it is necessary to characterize the ice nucleation activity (INA), defined as the ability of a tissue to induce heterogeneous ice nucleation. Few studies have addressed the precise localization of INA in wintering plant tissues in respect of its function. For this purpose, we recently revised a test tube INA assay and examined INA in various tissues of over 600 species. Extremely high levels of INA (−1 to −4 °C) in two wintering blueberry cultivars of contrasting freezing tolerance were found. Their INA was much greater than in other cold-hardy species and was found to be evenly distributed along the stems of the current year's growth. Concentrations of active ice nuclei in the stem were estimated from quantitative analyses. Stem INA was localized mainly in the bark while the xylem and pith had much lower INA. Bark INA was located mostly in the cell wall fraction (cell walls and intercellular structural components). Intracellular fractions had much less INA. Some cultivar differences were identified. The results corresponded closely with the intrinsic freezing behaviour (extracellular freezing) of the bark, icicle accumulation in the bark and initial ice nucleation in the stem under dry surface conditions. Stem INA was resistant to various antimicrobial treatments. These properties and specific localization imply that high INA in blueberry stems is of intrinsic origin and contributes to the spontaneous initiation of freezing in extracellular spaces of the bark by acting as a subfreezing temperature sensor. PMID:25082142

  15. Model-based optimization of the primary drying step during freeze-drying

    DEFF Research Database (Denmark)

    Mortier, Séverine Thérèse F.C.; Van Bockstal, Pieter-Jan; Nopens, Ingmar

    2015-01-01

    Since large molecules are considered the key driver for growth of the pharmaceutical industry, the focus of the pharmaceutical industry is shifting from small molecules to biopharmaceuticals: around 50% of the approved biopharmaceuticals are freeze-dried products. Therefore, freeze- drying is an ...

  16. Cod and rainbow trout as freeze-chilled meal elements

    DEFF Research Database (Denmark)

    Jensen, Louise Helene Søgaard; Nielsen, Jette; Jørgensen, Bo

    2010-01-01

    Meal elements' are elements of a meal, e.g. portions of pre-fried meat, sauces, frozen fish or pre-processed vegetables typically prepared industrially. The meal elements are distributed to professional satellite kitchens, where the staff can combine them into complete meals. Freeze......-chilling is a process consisting of freezing and frozen storage followed by thawing and chilled storage. Combining the two would enable the manufacturer to produce large quantities of frozen meal elements to be released into the chill chain according to demand. We have studied the influence of freeze...... days of chilled storage, and the corresponding time for rainbow trout was 10 days. After this period the sensory quality decreased and chemical indicators of spoilage were seen to increase. CONCLUSION: The consistent quality during storage and the high-quality shelf life are practically applicable...

  17. Freeze-tolerance of Trichinella muscle larvae in experimentally infected wild boars

    DEFF Research Database (Denmark)

    Lacour, Sandrine A.; Heckmann, Aurelie; Mace, Pauline

    2013-01-01

    served as negative controls. All wild boars were sacrificed 24 wpi. Muscle samples of 70 g were stored at -21 degrees C for 19,30 and 56h, and for 1-8 weeks. Larvae were recovered by artificial digestion. Their mobilities were recorded using Saisam (R) image analysis software and their infectivities were......Freeze-tolerance of encapsulated Trichinella muscle larvae (ML) is mainly determined by Trichinella species, but is also influenced by host species, the age of the infection and the storage time and temperature of the infected meat. Moreover, the freeze-tolerance of the encapsulated species appears...... to be correlated to the development of thick capsule walls which increases with age. An extended infection period and the muscle composition in some hosts (e.g. herbivores) may provide freeze-avoiding matrices due to high carbohydrate contents. The present experiment compares freeze-tolerance of Trichinella...

  18. Prediction model for carbonation depth of concrete subjected to freezing-thawing cycles

    Science.gov (United States)

    Xiao, Qian Hui; Li, Qiang; Guan, Xiao; Xian Zou, Ying

    2018-03-01

    Through the indoor simulation test of the concrete durability under the coupling effect of freezing-thawing and carbonation, the variation regularity of concrete neutralization depth under freezing-thawing and carbonation was obtained. Based on concrete carbonation mechanism, the relationship between the air diffusion coefficient and porosity in concrete was analyzed and the calculation method of porosity in Portland cement concrete and fly ash cement concrete was investigated, considering the influence of the freezing-thawing damage on the concrete diffusion coefficient. Finally, a prediction model of carbonation depth of concrete under freezing-thawing circumstance was established. The results obtained using this prediction model agreed well with the experimental test results, and provided a theoretical reference and basis for the concrete durability analysis under multi-factor environments.

  19. Assessing storage of stability and mercury reduction of freeze-dried Pseudomonas putida within different types of lyoprotectant

    Science.gov (United States)

    Azoddein, Abdul Aziz Mohd; Nuratri, Yana; Azli, Faten Ahada Mohd; Bustary, Ahmad Bazli

    2017-12-01

    Pseudomonas putida is a potential strain in biological treatment to remove mercury contained in the effluent of petrochemical industry due to its mercury reductase enzyme that able to reduce ionic mercury to elementary mercury. Freeze-dried P. putida allows easy, inexpensive shipping, handling and high stability of the product. This study was aimed to freeze dry P. putida cells with addition of lyoprotectant. Lyoprotectant was added into the cells suspension prior to freezing. Dried P. putida obtained was then mixed with synthetic mercury. Viability of recovery P. putida after freeze dry was significantly influenced by the type of lyoprotectant. Among the lyoprotectants, tween 80/ sucrose was found to be the best lyoprotectant. Sucrose was able to recover more than 78% (6.2E+09 CFU/ml) of the original cells (7.90E+09CFU/ml) after freeze dry and able to retain 5.40E+05 viable cells after 4 weeks storage at 4 °C without vacuum. Polyethylene glycol (PEG) pre-treated freeze dried cells and broth pre-treated freeze dried cells after the freeze-dry process recovered more than 64% (5.0 E+09CFU/ml) and >0.1% (5.60E+07CFU/ml). Freeze-dried P. putida cells in PEG and broth cannot survive after 4 weeks storage. Freeze dry also does not really change the pattern of growth P. putida but extension of lag time was found 1 hour after 3 weeks of storage. Additional time was required for freeze-dried P. putida cells to recover before introducing freeze-dried cells to more complicated condition such as mercury solution. The maximum mercury reduction of PEG pre-treated freeze-dried cells after freeze dry and after storage of 3 weeks was 17.91 %. The maximum of mercury reduction of tween 80/sucrose pre-treated freeze-dried cells after freeze dry and after storage 3 weeks was 25.03%. Freeze dried P. putida was found to have lower mercury reduction compare to the fresh P. putida that has been grown in agar. Result from this study may be beneficial and useful as initial reference before

  20. A Numerical and Experimental Investigation of the Internal Flow of a Freezing Water Droplet

    OpenAIRE

    Karlsson, Linn

    2015-01-01

    The overarching aim of this work is to study the freezing process of a single water droplet freezing on a cold surface, which is an interesting and important phenomenon with possible applications in many areas. Understanding the freezing process of a single water droplet is for example an important step when preventing unwanted icing, e.g. in the case of airplane wings and propellers, wind turbine rotor blades, and road surfaces.As a step in understanding the freezing process, the study speci...

  1. Freeze concentration of dairy products Phase 2. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Best, D.E.; Vasavada, K.C.

    1993-09-01

    An efficient, electrically driven freeze concentration system offers potential for substantially increasing electricity demand while providing the mature dairy industry with new products for domestic and export markets together with enhanced production efficiencies. Consumer tests indicate that dairy products manufactured from freeze-concentrated ingredients are either preferred or considered equivalent in quality to fresh milk-based products. Economic analyses indicate that this technology should be competitive with thermal evaporation processes on a commercial basis.

  2. Simulation Study on Freeze-drying Characteristics of Mashed Beef

    OpenAIRE

    Tambunan, Armansyah H; Solahudin, M; Rahajeng, Estri

    2000-01-01

    Drying characteristic of a particular product is important in analyzing the appropriateness of the drying method for the product. This is especially important for freeze drying, which is known as the most expensive drying method, asideji-om its good drying quality. The objectives of this experiment are to develop a computer simulation program using a retreating drying-frontmodel for predicting freeze drying characteristics of mashed nteat, especially for the influence of sublimation temperatu...

  3. Sintering of a freeze-dried 10 mol% Y2O3-stabilized zirconia

    International Nuclear Information System (INIS)

    Rakotoson, A.; Paulus, M.

    1983-01-01

    After presenting the results of freeze drying a sulfate solution, the authors describe a preparation process in which the freeze-drying technique by addition of a suspension of stabilized zirconia in the liquid solution before freeze-drying. This process breaks the polymeric chains, increases the green density of the compact, and decreases the sintering temperature. The mechanisms involved are discussed

  4. Freeze-dried spermatozoa: An alternative biobanking option for endangered species.

    Science.gov (United States)

    Anzalone, Debora Agata; Palazzese, Luca; Iuso, Domenico; Martino, Giuseppe; Loi, Pasqualino

    2018-03-01

    In addition to the iconic wild species, such as the pandas and Siberian tigers, an ever-increasing number of domestic species are also threatened with extinction. Biobanking of spermatozoa could preserve genetic heritages of extinct species, and maintain biodiversity of existing species. Because lyophilized spermatozoa retain fertilizing capacity, the aim was to assess whether freeze-dried spermatozoa are an alternative option to save endangered sheep breeds. To achieve this objective, semen was collected from an Italian endangered sheep breed (Pagliarola), and a biobank of cryopreserved and freeze-dried spermatozoa was established, and evaluated using IVF (for frozen spermatozoa) and ICSI procedures (for frozen and freeze-dried spermatozoa). As expected, the fertilizing capacity of cryopreserved Pagliarola's spermatozoa was comparable to commercial semen stocks. To evaluate the activating capability of freeze-dried spermatozoa, 108 MII sheep oocytes were subjected to ICSI, and allocated to two groups: 56 oocytes were activated by incubation with ionomycin (ICSI-FDSa) and 52 were not activated (ICSI-FDSna). Pronuclear formation (2PN) was investigated at 14-16 h after ICSI in fixed presumptive zygotes. Only artificially activated oocytes developed into blastocysts after ICSI. In the present study, freeze-dried ram spermatozoa induced blastocyst development following ICSI at a relatively high proportion, providing evidence that sperm lyophilization is an alternative, low cost storage option for biodiversity preservation of domestic species. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Tracheid diameter is the key trait determining the extent of freezing-induced embolism in conifers.

    Science.gov (United States)

    Pittermann, Jarmila; Sperry, John

    2003-09-01

    We tested the hypotheses that freezing-induced embolism is related to conduit diameter, and that conifers and angiosperms with conduits of equivalent diameter will exhibit similar losses of hydraulic conductivity in response to freezing. We surveyed the freeze-thaw response of conifers with a broad range of tracheid diameters by subjecting wood segments (root, stem and trunk wood) to a freeze-thaw cycle at -0.5 MPa in a centrifuge. Embolism increased as mean tracheid diameter exceeded 30 microm. Tracheids with a critical diameter greater than 43 microm were calculated to embolize in response to freezing and thawing at a xylem pressure of -0.5 MPa. To confirm that freezing-induced embolism is a function of conduit air content, we air-saturated stems of Abies lasiocarpa (Hook.) Nutt. (mean conduit diameter 13.7 +/- 0.7 microm) by pressurizing them 1 to 60 times above atmospheric pressure, prior to freezing and thawing. The air saturation method simulated the effect of increased tracheid size because the degree of super-saturation is proportional to a tracheid volume holding an equivalent amount of dissolved air at ambient pressure. Embolism increased when the dissolved air content was equivalent to a mean tracheid diameter of 30 microm at ambient air pressure. Our centrifuge and air-saturation data show that conifers are as vulnerable to freeze-thaw embolism as angiosperms with equal conduit diameter. We suggest that the hydraulic conductivity of conifer wood is maximized by increasing tracheid diameters in locations where freezing is rare. Conversely, the narrowing of tracheid diameters protects against freezing-induced embolism in cold climates.

  6. Determination of the dew point and the frost point below 0 degrees C making use of the beta-ray backscattering and the electric conductivity on the narrow surface of insulated layer.

    Science.gov (United States)

    Matsumoto, S; Kobayashi, H

    1979-10-15

    It is necessary to distinguish between the dew point and the frost point below 0 degrees C. The freezing of the dew and the melting of the frost are respectively detected by the rapid decrease and the increase of the conduction current on the narrow surface of insulated layer made of epoxy, 0.5 mm in width and 10 mm in length, on which the dew deposits. The dew point -9 degrees C and the frost point -8 degrees C in the humidity 21% at the temperature 13 degrees C are clearly distinguished in this method.

  7. INFLUENCE OF THE FREEZING PROCESS ON NATIONAL QUALITY FLOUR PRODUCTS (OSSETIAN PIES

    Directory of Open Access Journals (Sweden)

    I. U. Kusova

    2014-01-01

    Full Text Available Summary. Satisfying the taste preferences of the main engine of people food. Abundance and diversity of varieties of products provided by the manufacturer to the consumer market, is a consequence of the increasing diversity of taste preferences. Along with the expansion of the range of bakery products, improve the quality and nutritional value, the main task is to preserve the manufacturers of products in a fresh state. To preserve freshness, extend shelf life without deterioration of organoleptic properties of bakery products is the most appropriate way to freeze them. This article determines the dynamics of the freezing process, depending on the kind of filling and semi-finished (raw blanks, blanks after proofing, baking blanks after partial or fully finished products and the relationship with the quality of products. The highest quality of frozen semi-finished products is achieved when subjected to freeze after partial baking the preform (50 % availability. The article shows that the freezing of products with filling blanks based on a change in his cheese lipid fractions decreased total lipid content due to their partial migration in the test portion of the blank, and there is some increase of peroxide and acid number. Similar changes occur during freezing most of the filling. In the case of freezing of products subjected to partial baking, lipid changes are less significant.

  8. Immersion freezing of ice nucleation active protein complexes

    Directory of Open Access Journals (Sweden)

    S. Hartmann

    2013-06-01

    Full Text Available Utilising the Leipzig Aerosol Cloud Interaction Simulator (LACIS, the immersion freezing behaviour of droplet ensembles containing monodisperse particles, generated from a Snomax™ solution/suspension, was investigated. Thereto ice fractions were measured in the temperature range between −5 °C to −38 °C. Snomax™ is an industrial product applied for artificial snow production and contains Pseudomonas syringae} bacteria which have long been used as model organism for atmospheric relevant ice nucleation active (INA bacteria. The ice nucleation activity of such bacteria is controlled by INA protein complexes in their outer membrane. In our experiments, ice fractions increased steeply in the temperature range from about −6 °C to about −10 °C and then levelled off at ice fractions smaller than one. The plateau implies that not all examined droplets contained an INA protein complex. Assuming the INA protein complexes to be Poisson distributed over the investigated droplet populations, we developed the CHESS model (stoCHastic modEl of similar and poiSSon distributed ice nuclei which allows for the calculation of ice fractions as function of temperature and time for a given nucleation rate. Matching calculated and measured ice fractions, we determined and parameterised the nucleation rate of INA protein complexes exhibiting class III ice nucleation behaviour. Utilising the CHESS model, together with the determined nucleation rate, we compared predictions from the model to experimental data from the literature and found good agreement. We found that (a the heterogeneous ice nucleation rate expression quantifying the ice nucleation behaviour of the INA protein complex is capable of describing the ice nucleation behaviour observed in various experiments for both, Snomax™ and P. syringae bacteria, (b the ice nucleation rate, and its temperature dependence, seem to be very similar regardless of whether the INA protein complexes inducing ice

  9. Freeze-dried processing of tungsten heavy alloys

    International Nuclear Information System (INIS)

    White, G.D.; Gurwell, W.E.

    1989-06-01

    Tungsten heavy alloy powders were produced from freeze-dried aqueous solutions of ammonium metatungstate and, principally, sulfates of Ni and Fe. The freeze-dried salts were calcined and hydrogen reduced to form very fine, homogeneous, low-density, W heavy alloy powders having a coral-like structure with elements of approximately 0.1 μm in diameter. The powders yield high green strength and sinterability. Tungsten heavy alloy powders of 70%, 90%, and 96% W were prepared by freeze drying, compacted, and solid-state (SS) sintered to fully density at temperatures as low as 1200 degree C and also at conventional liquid-phase (LP) sintering temperatures. Solid-state sintered microstructures contained polygonal W grains with high contiguity; the matrix did not coat and separate the W grains to form low-contiguity, high-ductility structures. Liquid-phase sintered microstructures were very conventional in appearance, having W spheroids of low contiguity. All these materials were found to be brittle. High levels of residual S accompanied by segregation of the S to all the microstructural interfaces are principally responsible for the brittleness; problems with S could be eliminated by using Fe and Ni nitrates rather than the sulfates. 9 refs., 22 figs., 3 tabs

  10. Experimental Study Regarding the Freezing and Thawing Dynamics of Spruce Wood

    Directory of Open Access Journals (Sweden)

    Maria - Bernadett SZMUTKU

    2013-03-01

    Full Text Available The article presents the results regarding theevolution of the temperature field in spruce wood(Picea abies L. during freezing at two differentfreezing rates: -100C/h (rapid freezing and -10C/h(slow freezing and then during thawing at +50C,+30°C, +50°C temperature.This approach aimed at simulating thetemperature variations which occur inside timberduring open air storage in winter in two situations(sudden vs. gradual drop of temperature, and thenwhen the timber enters the drying kiln, depending onthe temperature applied in the initial heating phase.The results clearly show that the freezing ratesignificantly influences the thawing time and speed,which increase by 13-17% in the case of slowly frozenwood (at -10C/min compared to rapidly frozen wood(at -100C/min. It was also established that theoptimum temperature in the heating-up phase whendrying frozen spruce is 300C instead of the usual500C. This value leads to much better dryinguniformity without significantly prolonging the dryingtime.

  11. Effects of aging and freezing/thawing sequence on quality attributes of bovine and

    Directory of Open Access Journals (Sweden)

    Hyun-Wook Kim

    2017-02-01

    Full Text Available Objective The effects of aging and freezing/thawing sequence on color, physicochemical, and enzymatic characteristics of two beef muscles (Mm. gluteus medius, GM and biceps femoris, BF were evaluated. Methods Beef muscles at 3 d postmortem were assigned to four different combinations of aging and freezing/thawing sequence as follows; aging at 2°C for 3 wk (A3, never-frozen control, freezing at −28°C for 2 wk then thawing (F2, frozen/thawed-only, aging at 2°C for 3 wk, freezing at −28°C for 2 wk then thawing (A3F2, and freezing at −28°C for 2 wk, thawing then further aging at 2°C for 3 wk (F2A3. Results No significant interactions between different aging/freezing/thawing treatments and muscle type on all measurements were found. Postmortem aging, regardless of aging/freezing/thawing sequence, had no impact on color stability of frozen/thawed beef muscles (p<0.05. F2A3 resulted in higher purge loss than F2 and A3F2 treatments (p<0.05. A3F2 and F2A3 treatments resulted in lower shear force of beef muscles compared to F2 (p<0.05. Although there was no significant difference in glutathione peroxidase (GSH-Px activity, F2A3 had the highest β-N-acetyl glucominidase (BNAG activity in purge, but the lowest BNAG activity in muscle (p<0.05. GM muscle exhibited higher total color changes and purge loss, and lower GSH-Px activity than BF muscle. Conclusion The results from this present study indicate that different combinations of aging/freezing/thawing sequence would result in considerable impacts on meat quality attributes, particularly thaw/purge loss and tenderness. Developing a novel freezing strategy combined with postmortem aging will be beneficial for the food/meat industry to maximize its positive impacts on tenderness, while minimizing thaw/purge loss of frozen/thawed meat.

  12. Effects of Artificial Supercooling Followed by Slow Freezing on the Microstructure and Qualities of Pork Loin

    OpenAIRE

    Kim, Yiseul; Hong, Geun-Pyo

    2016-01-01

    This study investigated the effects of artificial supercooling followed by still air freezing (SSF) on the qualities of pork loin. The qualities of pork frozen by SSF were compared with the fresh control (CT, stored at 4? for 24 h), slow freezing (SAF, still air freezing) and rapid freezing (EIF, ethanol immersion freezing) treatments. Compared with no supercooling phenomena of SAF and EIF, the extent of supercooling obtained by SSF treatment was 1.4?. Despite that SSF was conducted with the ...

  13. The effect of variety and maturity on the quality of freeze-dried carrots. The effect of microwave blanching on the nutritional and textural quality of freeze-dried spinach

    Science.gov (United States)

    1979-01-01

    Using carrots, the quality of freeze-dried products was studied to determine the optimum varieties and maturation stages for quality attributes such as appearance, flavor, texture, and nutritive value. The quality of freeze-dried carrots is discussed in terms of Gardner color, alcohol insoluble solids, viscosity, and core/cortex ratio. Also, microwave blanching of freeze-dried spinach was studied to determine vitamin interrelationships, anatomical changes, and oxidative deteriorations in terms of preprocessing microwave treatments. Statistical methods were employed in the gathering of data and interpretation of results in both studies.

  14. Contact freezing of supercooled cloud droplets on collision with mineral dust particles: effect of particle size

    Science.gov (United States)

    Hoffmann, Nadine; Duft, Denis; Kiselev, Alexei; Leisner, Thomas

    2013-04-01

    The contact freezing of supercooled cloud droplets is one of the potentially important and the least investigated heterogeneous mechanism of ice formation in the tropospheric clouds [1]. On the time scales of cloud lifetime the freezing of supercooled water droplets via contact mechanism may occur at higher temperature compared to the same IN immersed in the droplet. However, the laboratory experiments of contact freezing are very challenging due to the number of factors affecting the probability of ice formation. In our experiment we study single water droplets freely levitated in the laminar flow of mineral dust particles acting as the contact freezing nuclei. By repeating the freezing experiment sufficient number of times we are able to reproduce statistical freezing behavior of large ensembles of supercooled droplets and measure the average rate of freezing events. We show that the rate of freezing at given temperature is governed only by the rate of droplet -particle collision and by the properties of the contact ice nuclei. In this contribution we investigate the relationship between the freezing probability and the size of mineral dust particle (represented by illite) and show that their IN efficiency scales with the particle size. Based on this observation, we discuss the similarity between the freezing of supercooled water droplets in immersion and contact modes and possible mechanisms of apparent enhancement of the contact freezing efficiency. [1] - K.C. Young, The role of contact nucleation in ice phase initiation in clouds, Journal of the Atmospheric Sciences 31, 1974

  15. FREEZE-OUT YIELDS OF RADIOACTIVITIES IN CORE-COLLAPSE SUPERNOVAE

    International Nuclear Information System (INIS)

    Magkotsios, Georgios; Wiescher, Michael; Timmes, F. X.

    2011-01-01

    We explore the nucleosynthesis trends from two mechanisms during freeze-out expansions in core-collapse supernovae. The first mechanism is related to the convection and instabilities within homogeneous stellar progenitor matter that is accreted through the supernova shock. The second mechanism is related to the impact of the supersonic wind termination shock (reverse shock) within the tumultuous inner regions of the ejecta above the proto-neutron star. Our results suggest that isotopes in the mass range 12 ≤ A ≤ 122 that are produced during the freeze-out expansions may be classified in two families. The isotopes of the first family manifest a common mass fraction evolutionary profile, whose specific shape per isotope depends on the characteristic transition between two equilibrium states (equilibrium state transition) during each type of freeze-out expansion. The first family includes the majority of isotopes in this mass range. The second family is limited to magic nuclei and isotopes in their locality, which do not sustain any transition, become nuclear flow hubs, and dominate the final composition. We use exponential and power-law adiabatic profiles to identify dynamic large-scale and small-scale equilibrium patterns among nuclear reactions. A reaction rate sensitivity study identifies those reactions that are crucial to the synthesis of radioactivities in the mass range of interest. In addition, we introduce non-monotonic parameterized profiles to probe the impact of the reverse shock and multi-dimensional explosion asymmetries on nucleosynthesis. Cases are shown in which the non-monotonic profiles favor the production of radioactivities. Non-monotonic freeze-out profiles involve longer non-equilibrium nucleosynthesis intervals compared with the exponential and power-law profiles, resulting in mass fraction trends and yield distributions that may not be achieved by the monotonic freeze-out profiles.

  16. Products and stability of phosphate reactions with lead under freeze-thaw cycling in simple systems

    International Nuclear Information System (INIS)

    Hafsteinsdottir, Erla G.; White, Duanne A.; Gore, Damian B.; Stark, Scott C.

    2011-01-01

    Orthophosphate fixation of metal contaminated soils in environments that undergo freeze-thaw cycles is understudied. Freeze-thaw cycling potentially influences the reaction rate, mineral chemical stability and physical breakdown of particles during fixation. This study determines what products form when phosphate (triple superphosphate [Ca(H 2 PO 4 ) 2 ] or sodium phosphate [Na 3 PO 4 ]) reacts with lead (PbSO 4 or PbCl 2 ) in simple chemical systems in vitro, and assesses potential changes in formation during freeze-thaw cycles. Systems were subjected to multiple freeze-thaw cycles from +10 deg. C to -20 deg. C and then analysed by X-ray diffractometry. Pyromorphite formed in all systems and was stable over multiple freeze-thaw cycles. Low temperature lead orthophosphate reaction efficiency varied according to both phosphate and lead source; the most time-efficient pyromorphite formation was observed when PbSO 4 and Na 3 PO 4 were present together. These findings have implications for the manner in which metal contaminated materials in freezing ground can be treated with phosphate. - Highlights: → Formation of lead phosphate products in cold environments is identified. → Potential change in formation during freeze-thaw cycling is assessed. → Lead phosphate reaction efficiency varies according to phosphate and lead source. → Pyromorphite formation is stable during 240 freeze-thaw cycles. - Pyromorphite, formed from Pb phosphate fixation, is stable during multiple freeze-thaw cycles but the efficiency of the fixation depends on the phosphate source and the type of Pb mineral.

  17. Reagan and the Nuclear Freeze: "Stars Wars" as a Rhetorical Strategy.

    Science.gov (United States)

    Bjork, Rebecca S.

    1988-01-01

    Analyzes the interaction between nuclear freeze activists and proponents of a Strategic Defense Initiative (SDI). Argues that SDI strengthens Reagan's rhetorical position concerning nuclear weapons policy because it reduces the argumentative ground of the freeze movement by envisioning a defensive weapons system that would nullify nuclear weapons.…

  18. Effects of annealing on the physical properties of therapeutic proteins during freeze drying process.

    Science.gov (United States)

    Lim, Jun Yeul; Lim, Dae Gon; Kim, Ki Hyun; Park, Sang-Koo; Jeong, Seong Hoon

    2018-02-01

    Effects of annealing steps during the freeze drying process on etanercept, model protein, were evaluated using various analytical methods. The annealing was introduced in three different ways depending on time and temperature. Residual water contents of dried cakes varied from 2.91% to 6.39% and decreased when the annealing step was adopted, suggesting that they are directly affected by the freeze drying methods Moreover, the samples were more homogenous when annealing was adopted. Transition temperatures of the excipients (sucrose, mannitol, and glycine) were dependent on the freeze drying steps. Size exclusion chromatography showed that monomer contents were high when annealing was adopted and also they decreased less after thermal storage at 60°C. Dynamic light scattering results exhibited that annealing can be helpful in inhibiting aggregation and that thermal storage of freeze-dried samples preferably induced fragmentation over aggregation. Shift of circular dichroism spectrum and of the contents of etanercept secondary structure was observed with different freeze drying steps and thermal storage conditions. All analytical results suggest that the physicochemical properties of etanercept formulation can differ in response to different freeze drying steps and that annealing is beneficial for maintaining stability of protein and reducing the time of freeze drying process. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Effect of Novel Quick Freezing Techniques Combined with Different Thawing Processes on Beef Quality

    Science.gov (United States)

    Yoo, Seon-Mi; Han, Gui-Jung

    2014-01-01

    This study investigated the effect of various freezing and thawing techniques on the quality of beef. Meat samples were frozen using natural convection freezing (NF), individual quick freezing (IQF), or cryogenic freezing (CF) techniques, followed by natural convection thawing (NCT) or running water thawing (RT). The meat was frozen until the core temperature reached -12℃ and then stored at -24℃, followed by thawing until the temperature reached 5℃. Quality parameters, such as the pH, water binding properties, CIE color, shear force, and microstructure of the beef were elucidated. Although the freezing and thawing combinations did not cause remarkable changes in the quality parameters, rapid freezing, in the order of CF, IQF, and NF, was found to minimize the quality deterioration. In the case of thawing methods, NCT was better than RT and the meat quality was influence on the thawing temperature rather than the thawing rate. Although the microstructure of the frozen beef exhibited an excessive loss of integrity after the freezing and thawing, it did not cause any remarkable change in the beef quality. Taken together, these results demonstrate that CF and NCT form the best combination for beef processing; however, IQF and NCT may have practical applications in the frozen food industry. PMID:26761674

  20. Chlorophyll fluorescence imaging accurately quantifies freezing damage and cold acclimation responses in Arabidopsis leaves

    Directory of Open Access Journals (Sweden)

    Hincha Dirk K

    2008-05-01

    Full Text Available Abstract Background Freezing tolerance is an important factor in the geographical distribution of plants and strongly influences crop yield. Many plants increase their freezing tolerance during exposure to low, nonfreezing temperatures in a process termed cold acclimation. There is considerable natural variation in the cold acclimation capacity of Arabidopsis that has been used to study the molecular basis of this trait. Accurate methods for the quantitation of freezing damage in leaves that include spatial information about the distribution of damage and the possibility to screen large populations of plants are necessary, but currently not available. In addition, currently used standard methods such as electrolyte leakage assays are very laborious and therefore not easily applicable for large-scale screening purposes. Results We have performed freezing experiments with the Arabidopsis accessions C24 and Tenela, which differ strongly in their freezing tolerance, both before and after cold acclimation. Freezing tolerance of detached leaves was investigated using the well established electrolyte leakage assay as a reference. Chlorophyll fluorescence imaging was used as an alternative method that provides spatial resolution of freezing damage over the leaf area. With both methods, LT50 values (i.e. temperature where 50% damage occurred could be derived as quantitative measures of leaf freezing tolerance. Both methods revealed the expected differences between acclimated and nonacclimated plants and between the two accessions and LT50 values were tightly correlated. However, electrolyte leakage assays consistently yielded higher LT50 values than chlorophyll fluorescence imaging. This was to a large part due to the incubation of leaves for electrolyte leakage measurements in distilled water, which apparently led to secondary damage, while this pre-incubation was not necessary for the chlorophyll fluorescence measurements. Conclusion Chlorophyll

  1. Chemistry of ice: Migration of ions and gases by directional freezing of water

    Directory of Open Access Journals (Sweden)

    Umer Shafique

    2016-09-01

    Full Text Available Redistribution of anions and cations creates an electrical imbalance in ice grown from electrolyte solutions. Movement of acidic and basic ions in cooling solutions can permanently change the pH of frozen and unfrozen parts of the system, largely. The extent of pH change associated with freezing is determined by solute concentration and the extent of cooling. In the present work, redistribution of hydrogen, hydroxyl, carbonate, and bicarbonate ions was studied during directional freezing in batch aqueous systems. Controlled freezing was employed vertically as well as radially in acidic and basic solutions. In each case, the ions substantially migrated along with moving freezing front. Conductometry and pH-metry were employed to monitor the moving ions. Besides, some other experiments were carried out with molecular gases, such as oxygen, carbon dioxide, and chlorine and an azeotropic mixture like water–ethanol. Findings can be used to understand possible changes that can occur in preserving materials by freezing.

  2. Optimisation of phenolic extraction from Averrhoa carambola pomace by response surface methodology and its microencapsulation by spray and freeze drying.

    Science.gov (United States)

    Saikia, Sangeeta; Mahnot, Nikhil Kumar; Mahanta, Charu Lata

    2015-03-15

    Optimised of the extraction of polyphenol from star fruit (Averrhoa carambola) pomace using response surface methodology was carried out. Two variables viz. temperature (°C) and ethanol concentration (%) with 5 levels (-1.414, -1, 0, +1 and +1.414) were used to design the optimisation model using central composite rotatable design where, -1.414 and +1.414 refer to axial values, -1 and +1 mean factorial points and 0 refers to centre point of the design. The two variables, temperature of 40°C and ethanol concentration of 65% were the optimised conditions for the response variables of total phenolic content, ferric reducing antioxidant capacity and 2,2-diphenyl-1-picrylhydrazyl scavenging activity. The reverse phase-high pressure liquid chromatography chromatogram of the polyphenol extract showed eight phenolic acids and ascorbic acid. The extract was then encapsulated with maltodextrin (⩽ DE 20) by spray and freeze drying methods at three different concentrations. Highest encapsulating efficiency was obtained in freeze dried encapsulates (78-97%). The obtained optimised model could be used for polyphenol extraction from star fruit pomace and microencapsulates can be incorporated in different food systems to enhance their antioxidant property. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. Properties of subvisible cirrus clouds formed by homogeneous freezing

    Directory of Open Access Journals (Sweden)

    B. Kärcher

    2002-01-01

    Full Text Available Number concentrations and mean sizes of ice crystals and derived microphysical and optical properties of subvisible cirrus clouds (SVCs formed by homogeneous freezing of supercooled aerosols are investigated as a function of temperature and updraft speed of adiabatically ascending air parcels. The properties of such clouds are insensitive to variations of the aerosol number and size distribution. Based on criteria constraining the optical extinction, sedimentation time, and existence time of SVCs, longer-lived (>10min clouds, capable of exerting a measurable radiative or chemical impact, are generated within a narrow range of updraft speeds below 1-2cm s-1 at temperatures below about 215K, with concentrations of ice crystals not exceeding 0.1cm-3. The clouds do not reach an equilibrium state because the ice crystals sediment out of the formation layer typically before the supersaturation is removed. Two important conclusions emerge from this work. First, the above characteristics of SVCs may provide an explanation for why SVCs are more common in the cold tropical than in the warmer midlatitude tropopause region. Second, it seems likely that a limited number (-3 of effective heterogeneous freezing nuclei that nucleate ice below the homogeneous freezing threshold can control the formation and properties of SVCs, although homogeneous freezing nuclei are far more abundant.

  4. Transcriptional and metabolomic analysis of Ascophyllum nodosum mediated freezing tolerance in Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Nair Prasanth

    2012-11-01

    Full Text Available Abstract Background We have previously shown that lipophilic components (LPC of the brown seaweed Ascophyllum nodosum (ANE improved freezing tolerance in Arabidopsis thaliana. However, the mechanism(s of this induced freezing stress tolerance is largely unknown. Here, we investigated LPC induced changes in the transcriptome and metabolome of A. thaliana undergoing freezing stress. Results Gene expression studies revealed that the accumulation of proline was mediated by an increase in the expression of the proline synthesis genes P5CS1 and P5CS2 and a marginal reduction in the expression of the proline dehydrogenase (ProDH gene. Moreover, LPC application significantly increased the concentration of total soluble sugars in the cytosol in response to freezing stress. Arabidopsis sfr4 mutant plants, defective in the accumulation of free sugars, treated with LPC, exhibited freezing sensitivity similar to that of untreated controls. The 1H NMR metabolite profile of LPC-treated Arabidopsis plants exposed to freezing stress revealed a spectrum dominated by chemical shifts (δ representing soluble sugars, sugar alcohols, organic acids and lipophilic components like fatty acids, as compared to control plants. Additionally, 2D NMR spectra suggested an increase in the degree of unsaturation of fatty acids in LPC treated plants under freezing stress. These results were supported by global transcriptome analysis. Transcriptome analysis revealed that LPC treatment altered the expression of 1113 genes (5% in comparison with untreated plants. A total of 463 genes (2% were up regulated while 650 genes (3% were down regulated. Conclusion Taken together, the results of the experiments presented in this paper provide evidence to support LPC mediated freezing tolerance enhancement through a combination of the priming of plants for the increased accumulation of osmoprotectants and alteration of cellular fatty acid composition.

  5. Effects of Artificial Supercooling Followed by Slow Freezing on the Microstructure and Qualities of Pork Loin

    Science.gov (United States)

    2016-01-01

    This study investigated the effects of artificial supercooling followed by still air freezing (SSF) on the qualities of pork loin. The qualities of pork frozen by SSF were compared with the fresh control (CT, stored at 4℃ for 24 h), slow freezing (SAF, still air freezing) and rapid freezing (EIF, ethanol immersion freezing) treatments. Compared with no supercooling phenomena of SAF and EIF, the extent of supercooling obtained by SSF treatment was 1.4℃. Despite that SSF was conducted with the same method with SAF, application of artificial supercooling accelerated the phase transition (traverse from -0.6℃ to -5℃) from 3.07 h (SAF) to 2.23 h (SSF). The observation of a microstructure indicated that the SSF prevented tissue damage caused by ice crystallization and maintained the structural integrity. The estimated quality parameters reflected that SSF exhibited superior meat quality compared with slow freezing (SAF). SSF showed better water-holding capacity (lower thawing loss, cooking loss and expressible moisture) and tenderness than SAF, and these quality parameters of SSF were not significantly different with ultra-fast freezing treatment (EIF). Consequently, the results demonstrated that the generation of supercooling followed by conventional freezing potentially had the advantage of minimizing the quality deterioration caused by the slow freezing of meat. PMID:27857541

  6. Effects of Artificial Supercooling Followed by Slow Freezing on the Microstructure and Qualities of Pork Loin.

    Science.gov (United States)

    Kim, Yiseul; Hong, Geun-Pyo

    2016-10-31

    This study investigated the effects of artificial supercooling followed by still air freezing (SSF) on the qualities of pork loin. The qualities of pork frozen by SSF were compared with the fresh control (CT, stored at 4℃ for 24 h), slow freezing (SAF, still air freezing) and rapid freezing (EIF, ethanol immersion freezing) treatments. Compared with no supercooling phenomena of SAF and EIF, the extent of supercooling obtained by SSF treatment was 1.4℃. Despite that SSF was conducted with the same method with SAF, application of artificial supercooling accelerated the phase transition (traverse from -0.6℃ to -5℃) from 3.07 h (SAF) to 2.23 h (SSF). The observation of a microstructure indicated that the SSF prevented tissue damage caused by ice crystallization and maintained the structural integrity. The estimated quality parameters reflected that SSF exhibited superior meat quality compared with slow freezing (SAF). SSF showed better water-holding capacity (lower thawing loss, cooking loss and expressible moisture) and tenderness than SAF, and these quality parameters of SSF were not significantly different with ultra-fast freezing treatment (EIF). Consequently, the results demonstrated that the generation of supercooling followed by conventional freezing potentially had the advantage of minimizing the quality deterioration caused by the slow freezing of meat.

  7. Influence of the Cavity Length on the Behavior of Hybrid Fixed-Point Cells Constructed at INRIM

    Science.gov (United States)

    Battuello, M.; Girard, F.; Florio, M.

    2015-03-01

    Hybrid cells with double carbon/carbon sheets are used at the Istituto Nazionale di Ricerca Metrologica (INRIM) for the realization of both pure metal fixed points and high-temperature metal-carbon eutectic points. Cells for the Cu and Co-C fixed points have been prepared to be used in the high-temperature fixed-point project of the Comité Consultatif de Thermométrie. The results of the evaluation processes were not completely satisfactory for the INRIM cells because of their low transition temperatures with respect to the best cells, and of a rather large melting range for the Co-C cell. A new design of the cells was devised, and considerable improvements were achieved with respect to the transition temperature, and the plateau shape and duration. As for the Cu point, the duration of the freezing plateaux increased by more than 50 % and the freezing temperature increased by 18 mK. As for the Co-C point, the melting temperature, expressed in terms of the point of inflection of the melting curve, increased by about 70 mK. The melting range of the plateaux, expressed as a difference was reduced from about 180 mK to about 130 mK, with melting times increased by about 50 %, as a consequence of an improvement of flatness and run-off of the plateaux.

  8. Effect of Latent Heat Released by Freezing Droplets during Frost Wave Propagation.

    Science.gov (United States)

    Chavan, Shreyas; Park, Deokgeun; Singla, Nitish; Sokalski, Peter; Boyina, Kalyan; Miljkovic, Nenad

    2018-05-21

    Frost spreads on nonwetting surfaces during condensation frosting via an interdroplet frost wave. When a supercooled condensate water droplet freezes on a hydrophobic or superhydrophobic surface, neighboring droplets still in the liquid phase begin to evaporate. Two possible mechanisms govern the evaporation of neighboring water droplets: (1) The difference in saturation pressure of the water vapor surrounding the liquid and frozen droplets induces a vapor pressure gradient, and (2) the latent heat released by freezing droplets locally heats the substrate, leading to evaporation of nearby droplets. The relative significance of these two mechanisms is still not understood. Here, we study the significance of the latent heat released into the substrate by freezing droplets, and its effect on adjacent droplet evaporation, by studying the dynamics of individual water droplet freezing on aluminum-, copper-, and glass-based hydrophobic and superhydrophobic surfaces. The latent heat flux released into the substrate was calculated from the measured droplet sizes and the respective freezing times ( t f ), defined as the time from initial ice nucleation within the droplet to complete droplet freezing. To probe the effect of latent heat release, we performed three-dimensional transient finite element simulations showing that the transfer of latent heat to neighboring droplets is insignificant and accounts for a negligible fraction of evaporation during microscale frost wave propagation. Furthermore, we studied the effect of substrate thermal conductivity on the transfer of latent heat transfer to neighboring droplets by investigating the velocity of ice bridge formation. The velocity of the ice bridge was independent of the substrate thermal conductivity, indicating that adjacent droplet evaporation during condensation frosting is governed solely by vapor pressure gradients. This study not only provides key insights into the individual droplet freezing process but also

  9. Multitarget transcranial direct current stimulation for freezing of gait in Parkinson's disease.

    Science.gov (United States)

    Dagan, Moria; Herman, Talia; Harrison, Rachel; Zhou, Junhong; Giladi, Nir; Ruffini, Giulio; Manor, Brad; Hausdorff, Jeffrey M

    2018-04-01

    Recent findings suggest that transcranial direct current stimulation of the primary motor cortex may ameliorate freezing of gait. However, the effects of multitarget simultaneous stimulation of motor and cognitive networks are mostly unknown. The objective of this study was to evaluate the effects of multitarget transcranial direct current stimulation of the primary motor cortex and left dorsolateral prefrontal cortex on freezing of gait and related outcomes. Twenty patients with Parkinson's disease and freezing of gait received 20 minutes of transcranial direct current stimulation on 3 separate visits. Transcranial direct current stimulation targeted the primary motor cortex and left dorsolateral prefrontal cortex simultaneously, primary motor cortex only, or sham stimulation (order randomized and double-blinded assessments). Participants completed a freezing of gait-provoking test, the Timed Up and Go, and the Stroop test before and after each transcranial direct current stimulation session. Performance on the freezing of gait-provoking test (P = 0.010), Timed Up and Go (P = 0.006), and the Stroop test (P = 0.016) improved after simultaneous stimulation of the primary motor cortex and left dorsolateral prefrontal cortex, but not after primary motor cortex only or sham stimulation. Transcranial direct current stimulation designed to simultaneously target motor and cognitive regions apparently induces immediate aftereffects in the brain that translate into reduced freezing of gait and improvements in executive function and mobility. © 2018 International Parkinson and Movement Disorder Society. © 2018 International Parkinson and Movement Disorder Society.

  10. Development of a freeze-stable formulation for vaccines containing aluminum salt adjuvants.

    Science.gov (United States)

    Braun, LaToya Jones; Tyagi, Anil; Perkins, Shalimar; Carpenter, John; Sylvester, David; Guy, Mark; Kristensen, Debra; Chen, Dexiang

    2009-01-01

    Vaccines containing aluminum salt adjuvants are prone to inactivation following exposure to freeze-thaw stress. Many are also prone to inactivation by heat. Thus, for maximum potency, these vaccines must be maintained at temperatures between 2 degrees C and 8 degrees C which requires the use of the cold chain. Nevertheless, the cold chain is not infallible. Vaccines are subject to freezing during both transport and storage, and frozen vaccines are discarded (under the best circumstances) or inadvertently administered despite potentially reduced potency. Here we describe an approach to minimize our reliance on the proper implementation of the cold chain to protect vaccines from freeze-thaw inactivation. By including PEG 300, propylene glycol, or glycerol in a hepatitis B vaccine, particle agglomeration, changes in the fluorescence emission spectrum--indicative of antigen tertiary structural changes--and losses of in vitro and in vivo indicators of potency were prevented following multiple exposures to -20 degrees C. The effect of propylene glycol was examined in more detail and revealed that even at concentrations too low to prevent freezing at -10 degrees C, -20 degrees C, and -80 degrees C, damage to the vaccine could be prevented. A pilot study using two commercially available diphtheria, tetanus toxoid, and acellular pertussis (DTaP) vaccines suggested that the same stabilizers might protect these vaccines from freeze-thaw agglomeration as well. It remains to be determined if preventing agglomeration of DTaP vaccines preserves their antigenic activity following freeze-thaw events.

  11. Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger

    Science.gov (United States)

    Ungar, Eugene K.; Schunk, Richard G.

    2011-01-01

    An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve a regenerative heat exchanger is placed inboard of the radiators. A regenerator cold side bypass valve is used to set the return temperature. During operation, the regenerator bypass flow is varied, mixing cold radiator return fluid and warm regenerator outlet fluid to maintain the system setpoint. At the lowest heat load for stable operation, the bypass flow is closed off, sending all of the flow through the regenerator. This lowers the radiator inlet temperature well below the system set-point while maintaining full flow through the radiators. By using a regenerator bypass flow control to maintain system setpoint, the required minimum heat load to avoid radiator freezing can be reduced by more than half compared to a radiator bypass system.

  12. Egg freezing and egg banking: empowerment and alienation in assisted reproduction.

    Science.gov (United States)

    Robertson, John A

    2014-06-01

    With the development of rapid freezing of human oocytes, many programs have reported IVF success rates comparable to those achieved with fresh eggs and thawed frozen embryos. Egg freezing is now gaining professional and regulatory acceptance as a safe and effective technique for women who wish to avoid discarding excess embryos, who face fertility-threatening medical treatments, or who want to preserve their eggs for use when they are better situated to have a family. This article focuses on the uses of and justification for egg freezing, the path to professional acceptance, the variability in success rates, and the controversy over freezing eggs for social rather than medical reasons. It also addresses the emergence of egg banking as a separate sector in the infertility industry, the regulatory issues that it poses, and its effect on egg donation. Key here is the legal control of stored eggs by banking women and their options when they wish to dispose of those eggs. The analysis is framed around empowerment and alienation. Egg freezing is generally empowering for women, but the donation or sale of unused eggs to infertile women, egg bankers, and researchers also raises issues of alienation.

  13. Arginine and proline applied as food additives stimulate high freeze tolerance in larvae of Drosophila melanogaster.

    Science.gov (United States)

    Koštál, Vladimír; Korbelová, Jaroslava; Poupardin, Rodolphe; Moos, Martin; Šimek, Petr

    2016-08-01

    The fruit fly Drosophila melanogaster is an insect of tropical origin. Its larval stage is evolutionarily adapted for rapid growth and development under warm conditions and shows high sensitivity to cold. In this study, we further developed an optimal acclimation and freezing protocol that significantly improves larval freeze tolerance (an ability to survive at -5°C when most of the freezable fraction of water is converted to ice). Using the optimal protocol, freeze survival to adult stage increased from 0.7% to 12.6% in the larvae fed standard diet (agar, sugar, yeast, cornmeal). Next, we fed the larvae diets augmented with 31 different amino compounds, administered in different concentrations, and observed their effects on larval metabolomic composition, viability, rate of development and freeze tolerance. While some diet additives were toxic, others showed positive effects on freeze tolerance. Statistical correlation revealed tight association between high freeze tolerance and high levels of amino compounds involved in arginine and proline metabolism. Proline- and arginine-augmented diets showed the highest potential, improving freeze survival to 42.1% and 50.6%, respectively. Two plausible mechanisms by which high concentrations of proline and arginine might stimulate high freeze tolerance are discussed: (i) proline, probably in combination with trehalose, could reduce partial unfolding of proteins and prevent membrane fusions in the larvae exposed to thermal stress (prior to freezing) or during freeze dehydration; (ii) both arginine and proline are exceptional among amino compounds in their ability to form supramolecular aggregates which probably bind partially unfolded proteins and inhibit their aggregation under increasing freeze dehydration. © 2016. Published by The Company of Biologists Ltd.

  14. Freezing issue on stability master production scheduling for supplier network: Decision making view

    Directory of Open Access Journals (Sweden)

    Aisyati Azizah

    2017-01-01

    Full Text Available In the daily operation, there are frequently changes in customer order requirement which will induce instability of the MPS. Moreover, the frequently adjustment of MPS can induce fluctuation of production and increasing of inventory cost as well as decreasing service level of customer. Most of studies about instability of MPS use freezing method and rolling procedure to adjust MPS periodically. Freezing is the proportion of planning horizon being frozen, whereas rolling procedure is a method replanning periodically of MPS using newly updated demand data. This study is focused on interval freezing length as an issue of decision making. In supply chain, a manufacturer is supported by suppliers to supply material requirement. Since a manufacturer plan production schedule on MPS the freezing interval is determined that will be informed to suppliers which supply the material requirement. In previous research, the freezing interval is decided by manufacturer as necessary decision maker. This decision must be followed by suppliers though it is not beneficial for them. It can be concluded that this condition is no win-win situation. Hence, this research proposes that suppliers will be involved as decision maker besides a manufacturer so the interval freezing is decided by two-side decision maker.

  15. Protection of fish oil from oxidation by microencapsulation using freeze-drying techniques

    DEFF Research Database (Denmark)

    Heinzelmann, K.; Franke, K.; Jensen, Benny

    2000-01-01

    (N-3)-Polyunsaturated fatty acids (PUFAs) reduce the risk of coronary heart disease. Cold sea water plankton and plankton- consuming fish are known sources of (n-3)-PUFAs. Enriching normal food components with fish oil is a tool for increasing the intake of (n-3)-PUFAs. Due to the high sensitivity...... different freezing techniques and subsequently freeze-dried. Several parameters regarding formulation and process (addition of antioxidants to the fish oil, use of carbohydrates, homogenisation and freezing conditions, initial freeze-drying temperature, grinding) were varied to evaluate their influence...... on the oxidative stability of dried microencapsulated fish oil. The shelf life of the produced samples was determined by measuring the development of volatile oxidation products vs. storage time. It could be shown that the addition of antioxidants to fish oil was necessary to produce dried microencapsulated fish...

  16. Effect of repeated freezing-thawing on the Achilles tendon of rabbits.

    Science.gov (United States)

    Chen, Lianxu; Wu, Yanping; Yu, Jiakuo; Jiao, Zhaode; Ao, Yingfang; Yu, Changlong; Wang, Jianquan; Cui, Guoqing

    2011-06-01

    The increased use of allograft tissue in the reconstruction of anterior cruciate ligament has brought more focus to the effect of storage and treatment on allograft. The purpose of this study was to observe the effect of histology and biomechanics on Achilles tendon in rabbits through repeated freezing-thawing before allograft tendon transplantation. Rabbit Achilles tendons were harvested and processed according to the manufacture's protocol of tissue bank, and freezing-thawing was repeated three times (group 1) and ten times (group 2). Those received only one cycle were used as controls. Then, tendons in each group were selected randomly to make for histological observations and biomechanics test. Histological observation showed that the following changes happened as the number of freezing-thawing increased: the arrangement of tendon bundles and collagen fibrils became disordered until ruptured, cells disrupted and apparent gaps appeared between tendon bundle because the formation of ice crystals. There were significant differences between the experimental and control groups in the values of maximum load, energy of maximum load and maximum stress, whereas no significant differences existed in other values such as stiffness, maximum strain, elastic modulus, and energy density. Therefore, repeated freezing-thawing had histological and biomechanical effect on Achilles tendon in rabbits before allograft tendon transplantation. This indicates that cautions should be taken in the repeated freezing-thawing preparation of allograft tendons in clinical application.

  17. Effects of freezing, freeze drying and convective drying on in vitro gastric digestion of apples.

    Science.gov (United States)

    Dalmau, Maria Esperanza; Bornhorst, Gail M; Eim, Valeria; Rosselló, Carmen; Simal, Susana

    2017-01-15

    The influence of processing (freezing at -196°C in liquid N2, FN sample; freeze-drying at -50°C and 30Pa, FD sample; and convective drying at 60°C and 2m/s, CD sample) on apple (var. Granny Smith) behavior during in vitro gastric digestion was investigated. Dried apples (FD and CD samples) were rehydrated prior to digestion. Changes in carbohydrate composition, moisture, soluble solids, acidity, total polyphenol content (TPC), and antioxidant activity (AA) of apple samples were measured at different times during digestion. Processing resulted in disruption of the cellular structure during digestion, as observed by scanning electron microscopy, light microscopy, and changes in carbohydrate composition. Moisture content increased (6-11% dmo), while soluble solids (55-78% dmo), acidity (44-72% dmo), total polyphenol content (30-61% dmo), and antioxidant activity (41-87%) decreased in all samples after digestion. Mathematical models (Weibull and exponential models) were used to better evaluate the influence of processing on apple behavior during gastric digestion. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Reduced early growing season freezing resistance in alpine treeline plants under elevated atmospheric CO2.

    NARCIS (Netherlands)

    Martin, M.; Gavazov, K.S.; Körner, S.; Rixen, C.

    2010-01-01

    The frequency of freezing events during the early growing season and the vulnerability to freezing of plants in European high-altitude environments could increase under future atmospheric and climate change. We tested early growing season freezing sensitivity in 10 species, from four plant

  19. Mechanisms of deterioration of nutrients. [freeze drying methods for space flight food

    Science.gov (United States)

    Karel, M.; Flink, J. M.

    1974-01-01

    Methods are reported by which freeze dried foods of improved quality will be produced. The applicability of theories of flavor retention has been demonstrated for a number of food polymers, both proteins and polysacchardies. Studies on the formation of structures during freeze drying have been continued for emulsified systems. Deterioration of organoleptic quality of freeze dried foods due to high temperature heating has been evaluated and improved procedures developed. The influence of water activity and high temperature on retention of model flavor materials and browning deterioration has been evaluated for model systems and food materials.

  20. Effect of pasteurisation and freezing method on bioactive compounds and antioxidant activity of strawberry pulp.

    Science.gov (United States)

    Gonçalves, Gilma Auxiliadora Santos; Resende, Nathane Silva; Carvalho, Elisângela Elena Nunes; Resende, Jaime Vilela de; Vilas Boas, Eduardo Valério de Barros

    2017-09-01

    This study evaluated the stability of strawberry pulp subjected to three factors, pasteurisation (pasteurised and unpasteurised), freezing method (static air and forced air) and storage time (0, 2, 4 and 6 months). Pasteurisation favoured vitamin C retention during storage but enhanced the total loss of phenolics without affecting anthocyanin levels. Freezing by forced air was more effective in retaining phenolics during the first 4 months of storage, although the freezing method did not affect the anthocyanin levels. Processing and storage reduced the levels of individual phenolics. Freezing by forced air was more effective than static air in retaining antioxidant activity of the pulp. Polyphenol oxidase and peroxidase enzyme levels were relatively stable and independent of pasteurisation, freezing and storage time. Even after 6 months of frozen storage, strawberry pulp is a significant source of nutrients and bioactive compounds and retains high antioxidant capacity independent of pasteurisation and freezing method.

  1. Sperm freezing to address the risk of azoospermia on the day of ICSI.

    Science.gov (United States)

    Montagut, M; Gatimel, N; Bourdet-Loubère, S; Daudin, M; Bujan, L; Mieusset, R; Isus, F; Parinaud, J; Leandri, R

    2015-11-01

    In which cases is freezing of ejaculated sperm indicated before ICSI? Sperm freezing should be performed only when out of two analyses at least one total sperm count in the ejaculate is lower than 10(6). Due to variations in individual sperm parameters, in cases of severe oligozoospermia there is a risk of absence of spermatozoa on the day of ICSI, leading to cancellation of the attempt. Sperm freezing can avoid this problem but little is known of the parameters governing the decision to freeze sperm or not. This retrospective study included 247 men who underwent sperm cryopreservation to prevent the risk of azoospermia on the day of ICSI, from 2000 to 2012. Receiver operating characteristic curve analysis was used to define the threshold value. The lowest total sperm count per ejaculate was studied as a predictive factor for the use of frozen sperm in a total of 593 ICSI attempts. Moreover, 2003 patients who had at least 4 semen analyses for andrological diagnosis have been studied to evaluate the reproducibility of sperm count. To evaluate the psychological impact of sperm freezing, a questionnaire was administered to 84 men who attended for sperm cryopreservation between June and December 2014. The cost of sperm freezing was analysed according to the French prices. When at least one total sperm count was counts were ≥10(5) (P sperm freezing is recommended when one analysis from at least two, showed a sperm count sperm freezings. The psychological impact of sperm freezing was good since >70% of men had positive feelings about this technique. This was a fairly short-term study and preservation of future fertility was not assessed. It appeared impossible to find a threshold that would predict the risk of azoospermia with 100% accuracy. Therefore there is still a risk of absence of spermatozoa on the day of ICSI despite a good negative predictive value when no total sperm count was lower than 10(5). These data suggest that sperm freezing should be proposed when

  2. Anhydrobiosis and freezing-tolerance: adaptations that facilitate the establishment of Panagrolaimus nematodes in polar habitats.

    Science.gov (United States)

    McGill, Lorraine M; Shannon, Adam J; Pisani, Davide; Félix, Marie-Anne; Ramløv, Hans; Dix, Ilona; Wharton, David A; Burnell, Ann M

    2015-01-01

    Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24 Panagrolaimus strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other Panagrolaimus isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth of ice crystals. We show that P. davidi belongs to a clade of anhydrobiotic and freezing-tolerant panagrolaimids containing strains from temperate and continental regions and that P. superbus, an early colonizer at Surtsey island, Iceland after its volcanic formation, is closely related to a species from Pennsylvania, USA. Ancestral state reconstructions show that anhydrobiosis evolved deep in the phylogeny of Panagrolaimus. The early-diverging Panagrolaimus lineages are strongly anhydrobiotic but weakly freezing-tolerant, suggesting that freezing tolerance is most likely a derived trait. The common ancestors of the davidi and the superbus clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of P. davidi do not show evidence of an evolved response to polar conditions. Thus we suggest that the colonization of Antarctica by P. davidi and of Surtsey by P. superbus may be examples of recent "ecological fitting

  3. Anhydrobiosis and freezing-tolerance: adaptations that facilitate the establishment of Panagrolaimus nematodes in polar habitats.

    Directory of Open Access Journals (Sweden)

    Lorraine M McGill

    Full Text Available Anhydrobiotic animals can survive the loss of both free and bound water from their cells. While in this state they are also resistant to freezing. This physiology adapts anhydrobiotes to harsh environments and it aids their dispersal. Panagrolaimus davidi, a bacterial feeding anhydrobiotic nematode isolated from Ross Island Antarctica, can survive intracellular ice formation when fully hydrated. A capacity to survive freezing while fully hydrated has also been observed in some other Antarctic nematodes. We experimentally determined the anhydrobiotic and freezing-tolerance phenotypes of 24 Panagrolaimus strains from tropical, temperate, continental and polar habitats and we analysed their phylogenetic relationships. We found that several other Panagrolaimus isolates can also survive freezing when fully hydrated and that tissue extracts from these freezing-tolerant nematodes can inhibit the growth of ice crystals. We show that P. davidi belongs to a clade of anhydrobiotic and freezing-tolerant panagrolaimids containing strains from temperate and continental regions and that P. superbus, an early colonizer at Surtsey island, Iceland after its volcanic formation, is closely related to a species from Pennsylvania, USA. Ancestral state reconstructions show that anhydrobiosis evolved deep in the phylogeny of Panagrolaimus. The early-diverging Panagrolaimus lineages are strongly anhydrobiotic but weakly freezing-tolerant, suggesting that freezing tolerance is most likely a derived trait. The common ancestors of the davidi and the superbus clades were anhydrobiotic and also possessed robust freezing tolerance, along with a capacity to inhibit the growth and recrystallization of ice crystals. Unlike other endemic Antarctic nematodes, the life history traits of P. davidi do not show evidence of an evolved response to polar conditions. Thus we suggest that the colonization of Antarctica by P. davidi and of Surtsey by P. superbus may be examples of recent

  4. A case history of a tunnel constructed by ground freezing

    Science.gov (United States)

    Lacy, H. S.; Jones, J. S., Jr.; Gidlow, B.

    Artificial ground freezing was used for structural support and groundwater control for a 37 m long, 3.2 m diameter tunnel located about 2 m beneath high speed railroad lines in Syracuse, New York. A double row of freeze pipes spaced approximately 0.9 m on-center was used around the periphery of the tunnel above the spring line, while only a single row of freeze pipes was required below the spring line. Excavation of the frozen soil within the tunnel was accomplished with a small road header tunnel boring machine. The results of in situ testing of frozen soil, laboratory testing of frozen soils, computer analysis to predict stress deformation-time characteristics under static and cyclic loading, the instrumentation program including a comparison of estimated and measured performance are discussed.

  5. Effects of gamma radiation on freeze-dried wheat seeds

    International Nuclear Information System (INIS)

    Ajayi, N.O.; Larsson, B.

    1975-07-01

    The effect of radiation on freeze-dried wheat seeds are reported. The response of the various parts of the seedling to radiation was found to differ from one another. There was no significant modification of the effect of radiation on the shoot and root growth, while the growth of the coleoptile was slightly reduced in the frezze-dried seeds. The change in the shoot growth-absorbed dose relationship reported by others to occur at high doses for oven-dried as compared to air-dried barley seeds was not seen for the control and freeze-dried wheat seeds. The freeze-dried seeds are believed to show only the effect of radiation without any modification due to drying as such. The dose-effect relationships may be splited into functions characterised by different radiosensitivity. The high sensitivty effect is mainly taking place within the first 40 krad of energy absorption, and the low sensitivity is dominating at higher doses. (author)

  6. Small copper fixed-point cells of the hybrid type to be used in place of normal larger cells

    Science.gov (United States)

    Battuello, M.; Girard, F.; Florio, M.

    2012-10-01

    Two small cells for the realization of the fixed point of copper were constructed and investigated at INRIM. They are of the same hybrid design generally adopted for the eutectic high-temperature fixed-point cells, namely a structure with a sacrificial graphite sleeve and a layer of flexible carbon-carbon composite sheet (C/C sheet). Because of the largely different design with respect to the cells normally adopted for the construction of pure metal fixed points, they were compared and characterized with respect to the normal cells used at INRIM for the ITS-90 realization. Two different furnaces were used to compare hybrid and normal cells. One of the hybrid cells was also used in different configurations, i.e. without the C/C sheet and with two layers of sheet. The cells were compared with different operative conditions, i.e. temperature settings of the furnaces for inducing the freeze, and repeatability and reproducibility were investigated. Freezing temperature and shape of the plateaux obtained under the different conditions were analysed. As expected the duration of the plateaux obtained with the hybrid cells is considerably shorter than with the normal cell, but this does not affect the results in terms of freezing temperature. Measurements with the modified cell showed that the use of a double C/C sheet may improve both repeatability and reproducibility of the plateaux.

  7. Small copper fixed-point cells of the hybrid type to be used in place of normal larger cells

    International Nuclear Information System (INIS)

    Battuello, M; Girard, F; Florio, M

    2012-01-01

    Two small cells for the realization of the fixed point of copper were constructed and investigated at INRIM. They are of the same hybrid design generally adopted for the eutectic high-temperature fixed-point cells, namely a structure with a sacrificial graphite sleeve and a layer of flexible carbon–carbon composite sheet (C/C sheet). Because of the largely different design with respect to the cells normally adopted for the construction of pure metal fixed points, they were compared and characterized with respect to the normal cells used at INRIM for the ITS-90 realization. Two different furnaces were used to compare hybrid and normal cells. One of the hybrid cells was also used in different configurations, i.e. without the C/C sheet and with two layers of sheet. The cells were compared with different operative conditions, i.e. temperature settings of the furnaces for inducing the freeze, and repeatability and reproducibility were investigated. Freezing temperature and shape of the plateaux obtained under the different conditions were analysed. As expected the duration of the plateaux obtained with the hybrid cells is considerably shorter than with the normal cell, but this does not affect the results in terms of freezing temperature. Measurements with the modified cell showed that the use of a double C/C sheet may improve both repeatability and reproducibility of the plateaux. (paper)

  8. Products and stability of phosphate reactions with lead under freeze-thaw cycling in simple systems

    Energy Technology Data Exchange (ETDEWEB)

    Hafsteinsdottir, Erla G., E-mail: erla.hafsteinsdottir@gmail.com [Department of Environment and Geography, Macquarie University, NSW 2109 (Australia); White, Duanne A., E-mail: duanne.white@mq.edu.au [Department of Environment and Geography, Macquarie University, NSW 2109 (Australia); Gore, Damian B., E-mail: damian.gore@mq.edu.au [Department of Environment and Geography, Macquarie University, NSW 2109 (Australia); Stark, Scott C., E-mail: scott.stark@aad.gov.au [Environmental Protection and Change, Australian Antarctic Division, Department of Sustainability, Environment, Water, Population and Communities, Tasmania 7050 (Australia)

    2011-12-15

    Orthophosphate fixation of metal contaminated soils in environments that undergo freeze-thaw cycles is understudied. Freeze-thaw cycling potentially influences the reaction rate, mineral chemical stability and physical breakdown of particles during fixation. This study determines what products form when phosphate (triple superphosphate [Ca(H{sub 2}PO{sub 4}){sub 2}] or sodium phosphate [Na{sub 3}PO{sub 4}]) reacts with lead (PbSO{sub 4} or PbCl{sub 2}) in simple chemical systems in vitro, and assesses potential changes in formation during freeze-thaw cycles. Systems were subjected to multiple freeze-thaw cycles from +10 deg. C to -20 deg. C and then analysed by X-ray diffractometry. Pyromorphite formed in all systems and was stable over multiple freeze-thaw cycles. Low temperature lead orthophosphate reaction efficiency varied according to both phosphate and lead source; the most time-efficient pyromorphite formation was observed when PbSO{sub 4} and Na{sub 3}PO{sub 4} were present together. These findings have implications for the manner in which metal contaminated materials in freezing ground can be treated with phosphate. - Highlights: > Formation of lead phosphate products in cold environments is identified. > Potential change in formation during freeze-thaw cycling is assessed. > Lead phosphate reaction efficiency varies according to phosphate and lead source. > Pyromorphite formation is stable during 240 freeze-thaw cycles. - Pyromorphite, formed from Pb phosphate fixation, is stable during multiple freeze-thaw cycles but the efficiency of the fixation depends on the phosphate source and the type of Pb mineral.

  9. The Effect of Freezing Temperatures on Microdochium majus and M. nivale Seedling Blight of Winter Wheat

    Directory of Open Access Journals (Sweden)

    Ian M. Haigh

    2012-01-01

    Full Text Available Exposure to pre-emergent freezing temperatures significantly delayed the rate of seedling emergence (P<0.05 from an infected and a non-infected winter wheat cv. Equinox seed lot, but significant effects for timing of freezing and duration of freezing on final emergence were only seen for the Microdochium-infested seed lot. Freezing temperatures of −5∘C at post-emergence caused most disease on emerged seedlings. Duration of freezing (12 hours or 24 hours had little effect on disease index but exposure to pre-emergent freezing for 24 hours significantly delayed rate of seedling emergence and reduced final emergence from the infected seed lot. In plate experiments, the calculated base temperature for growth of M. nivale and M. majus was −6.3∘C and −2.2∘C, respectively. These are the first set of experiments to demonstrate the effects of pre-emergent and post-emergent freezing on the severity of Microdochium seedling blight.

  10. Impact of the industrial freezing process on selected vegetables -Part II. Colour and bioactive compounds

    NARCIS (Netherlands)

    Mazzeo, Teresa; Paciulli, Maria; Chiavaro, Emma; Visconti, Attilio; Fogliano, Vincenzo; Ganino, Tommaso; Pellegrini, Nicoletta

    2015-01-01

    In the present study, the impact of the different steps (i.e. blanching, freezing, storage following the industrial freezing process and the final cooking prior to consumption) of the industrial freezing process was evaluated on colour, chlorophylls, lutein, polyphenols and ascorbic acid content

  11. Optimization of the freezing process for hematopoietic progenitor cells: effect of precooling, initial dimethyl sulfoxide concentration, freezing program, and storage in vapor-phase or liquid nitrogen on in vitro white blood cell quality.

    Science.gov (United States)

    Dijkstra-Tiekstra, Margriet J; Setroikromo, Airies C; Kraan, Marcha; Gkoumassi, Effimia; de Wildt-Eggen, Janny

    2014-12-01

    Adding dimethyl sulfoxide (DMSO) to hematopoietic progenitor cells (HPCs) causes an exothermic reaction, potentially affecting their viability. The freezing method might also influence this. The aim was to investigate the effect of 1) precooling of DMSO and plasma (D/P) and white blood cell (WBC)-enriched product, 2) DMSO concentration of D/P, 3) freezing program, and 4) storage method on WBC quality. WBC-enriched product without CD34+ cells was used instead of HPCs. This was divided into six or eight portions. D/P (20 or 50%; precooled or room temperature [RT]) was added to the WBC-enriched product (precooled or RT), resulting in 10% DMSO, while monitoring temperature. The product was frozen using controlled-rate freezing ("fast-rate" or "slow-rate") and placed in vapor-phase or liquid nitrogen. After thawing, WBC recovery and viability were determined. Temperature increased most for precooled D/P to precooled WBC-enriched product, without influence of 20 or 50% D/P, but remained for all variations below 30°C. WBC recovery for both freezing programs was more than 95%. Recovery of WBC viability was higher for slow-rate freezing compared to fast-rate freezing (74% vs. 61%; p liquid nitrogen was marginal. Based on these results, precooling is not necessary. Fifty percent D/P is preferred over 20% D/P. Slow-rate freezing is preferred over fast-rate freezing. For safety reasons storage in vapor-phase nitrogen is preferred over storage in liquid nitrogen. Additional testing using real HPCs might be necessary. © 2014 AABB.

  12. Evaluation and Comparison of Freeze-Thaw Tests and Air Void Analysis of Pervious Concrete

    DEFF Research Database (Denmark)

    Lund, Mia Schou Møller; Hansen, Kurt Kielsgaard; Kevern, John T.

    2016-01-01

    Pearl-Chain Bridge technology is an innovative precast arch bridge solution which uses pervious concrete as fill material. To ensure longevity of the bridge superstructure it is necessary that the per-vious concrete fill is designed to be freeze-thaw durable; however, no standards exist on how...... to eval-uate the freeze-thaw resistance of fresh or hardened pervious concrete and correspondingly what constitutes acceptable freeze-thaw durability. A greater understanding of the correlation between the freeze-thaw performance and the air void structure of pervious concrete is needed. In the present...... study six pervious concrete mixes were exposed to freeze-thaw testing, and their air void structure was analyzed using an automated linear-traverse method. It was found that there is a miscorrelation between these two test methods in their assumption of whether or not the large interconnected voids...

  13. Evaluation of freeze-thaw durability of pervious concrete by use of operational modal analysis

    DEFF Research Database (Denmark)

    Lund, M.S.M.; Hansen, K. K.; Brincker, R.

    2018-01-01

    It is well-known that laboratory testing of pervious concrete's freeze-thaw performance is too harsh and does not agree well with field observations. The most commonly used laboratory freeze-thaw test method for pervious concrete is similar to that used for conventional concrete even though...... the void structure of the two materials is completely different. In the present study, a new freeze-thaw test method for pervious concrete is suggested and tested on one baseline mix, with three different contents of entrained air. The evaluation of freeze-thaw damage on pervious concrete beams...... was evaluated from the decrease in mass and from operational modal analysis which provides an accurate determination of the change in natural frequencies with freeze-thaw exposure. Operational modal analysis was also used to determine the Young's modulus, shear modulus, and Poisson's ratio of the pervious...

  14. Evaluation of Freeze Tolerance in Lancelot Plantain (Plantago lanceolata L. Ecotypes under Controlled Conditions

    Directory of Open Access Journals (Sweden)

    M. Janalizadeh

    2016-02-01

    Full Text Available Introduction Lancelot Plantain (Ribwort, narrow-leaf or English plantain is a deep-rooted, short-lived perennial herb from Plantaginaceae family which has been used for various medicinal purposes for centuries, especially in Europe and only more recently has been proposed as a forage plant. The leaf of plantain is highly palatable for grazing animals, providing mineral-rich forage. Recently two productive upright cultivars of plantain have been bred and introduced, Grasslands Lancelot and the more erect winter active Ceres Tonic. Plantain grows moderately in winter but its main growth periods beings in spring and autumn with opportunistic summer growth. Although it reveals suitable winter survival in natural conditions, but there is not a lot of information about cold tolerance of this plant. So it is important to recognize the freeze tolerance of narrow leaf plantain for successful planting and utilization in cold regions such as Mashhad in Khorasan Razavi Province (Northeast of Iran. Determining LT50 point or critical temperature for survival of plant is the most reliable and simple method for evaluating cold tolerance of plants. Another reliable method for freeze tolerance of plants is estimation of temperature at which 50 % of dry matter reduces (RDMT50. This experiment was carried out to evaluate freeze tolerance of five ecotypes of Lancelot plantain according to the LT50su and RDMT50 indices. Materials and Methods In order to evaluate freeze tolerance of Lancelot plantain, a factorial experiment based on completely randomized design with three replications was carried out under controlled conditions at college of agriculture, Ferdowsi University of Mashhad. Five ecotypes of Lancelot plantain (Bojnourd, Kalat, Mashhad, Ghayen and Birjand after three months growth and hardening in natural environment were transferred to a Thermo gradient freezer on January 20th, 2012 and exposed to eight freezing temperatures (Zero, -3, -6, -9, -12, -15, -18

  15. Rapid assessment of iron in blood plasma and serum by spectrophotometry with cloud-point extraction [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Tatyana Samarina

    2015-08-01

    Full Text Available Rapid photometric assessment of iron in blood plasma and serum by a simple procedure after the extraction of iron(II complex with 1-nitroso-2-naphthol in the micellar phase of a nonionic surfactant at the cloud point upon heating (pH range is 4.5–6.3 is proposed. The procedure trueness was verified using a standard reference protocol using bathophenanthroline. The advantages of the procedure are higher sensitivity than the reference protocol: the limit of detection is 0.03 μg/mL, the limit of quantitation is 0.1 μg/mL, the determination range is 0.1 – 2.8 μg/mL (RSD 0.02–0.10. Copper does not interfere with the iron assessment.

  16. Rehydration kinetics of freeze-dried carrots

    NARCIS (Netherlands)

    Vergeldt, F.J.; Dalen, van G.; Duijster, A.J.; Voda, A.; Khalloufi, S.; Vliet, van L.J.; As, van H.; Duynhoven, van J.P.M.; Sman, van der R.G.M.

    2014-01-01

    Rehydration kinetics by two modes of imbibition is studied in pieces of freeze-dried winter carrot, after different thermal pre-treatments. Water ingress at room temperature is measured in real time by in situ MRI and NMR relaxometry. Blanched samples rehydrate substantially faster compared to

  17. A novel freeze-dried storage and preparation method for the determination of mycophenolic acid in plasma by high-performance liquid chromatography.

    Science.gov (United States)

    Wang, Lei; Qiang, Wei; Li, Ying; Cheng, Zeneng; Xie, Mengmeng

    2017-09-01

    Plasma samples were conventionally stored at freezing conditions until the time of detection. Such a technique, when carried out over an extended period, is energy consuming; in addition, preparation and transportation of stored samples is inconvenient. In this study, a freeze-dried storage and preparation method was proposed to determine the presence of mycophenolic acid (MPA) in plasma. Fresh plasma samples were freeze-dried using a device, and then stored at ambient temperature. After the stored samples were soaked with methanol spiked with the internal standard, high-performance liquid chromatography was conducted to detect MPA. The proposed method was demonstrated to be precise and accurate over the linear range of 0.5-50 μg mL -1 , with both intra- and inter-day precision being plasma concentration, time point of maximum plasma concentration and elimination half-life, among others, were consistent with the results in the published study. This proposed technique was proved to be simple, reproducible and energy saving. This approach could also simplify the storage and analysis of samples in clinical and scientific drug research. Copyright © 2017 John Wiley & Sons, Ltd.

  18. Fabrication of Chitosan Silk-based Tracheal Scaffold Using Freeze-Casting Method

    Science.gov (United States)

    Nematollahi, Zeinab; Tafazzoli-Shadpour, Mohammad; Zamanian, Ali; Seyedsalehi, Amir; Mohammad-Behgam, Shadmehr; Ghorbani, Fariba; Mirahmadi, Fereshte

    2017-01-01

    Background: Since the treatments of long tracheal lesions are associated with some limitations, tissue engineered trachea is considered as an alternative option. This study aimed at preparing a composite scaffold, based on natural and synthetic materials for tracheal tissue engineering. Methods: Nine chitosan silk-based scaffolds were fabricated using three freezing rates (0.5, 1, and 2°C/min) and glutaraldehyde (GA) concentrations (0, 0.4, and 0.8 wt%). Samples were characterized, and scaffolds having mechanical properties compatible with those of human trachea and proper biodegradability were selected for chondrocyte cell seeding and subsequent biological assessments. Results: The pore sizes were highly influenced by the freezing rate and varied from 135.3×372.1 to 37.8×83.4 µm. Swelling and biodegradability behaviors were more affected by GA rather than freezing rate. Tensile strength raised from 120 kPa to 350 kPa by an increment of freezing rate and GA concentration. In addition, marked stiffening was demonstrated by increasing elastic modulus from 1.5 MPa to 12.2 MPa. Samples having 1 and 2°C/min of freezing rate and 0.8 wt% GA concentration made a non-toxic, porous structure with tensile strength and elastic modulus in the range of human trachea, facilitating the chondrocyte proliferation. The results of 21-day cell culture indicated that glycosaminoglycans content was significantly higher for the rate of 2°C/min (12.04 µg/min) rather than the other (9.6 µg/min). Conclusion: A homogenous porous structure was created by freeze drying. This allows the fabrication of a chitosan silk scaffold cross-linked by GA for cartilage tissue regeneration with application in tracheal regeneration. PMID:28131109

  19. Cryopreservation of Iberian pig spermatozoa. Comparison of different freezing extenders based on post-thaw sperm quality.

    Science.gov (United States)

    De Mercado, Eduardo; Rodríguez, Ana; Gómez, Emilio; Sanz, Elena

    2010-03-01

    The aim of this study was to evaluate the cryoprotective effect of different freezing extenders against cryopreservation injuries on Iberian boar sperm. The sperm-rich fraction was collected and pooled from six sexually mature Iberian boars, and was frozen in different extenders containing glucose, lactose or fructose as sugar source and including Orvus ES Paste only in the freezing extender-2 (Glucose; Lactose and Fructose) or in both freezing extenders (Glucose2; Lactose2 and Fructose2). During the cryopreservation process, the supernatant was removed after the centrifugation step, then was extended with freezing extender-1 for the equilibration period and with freezing extender-2 immediately before freezing. Post-thaw sperm characteristics, such as plasma membrane integrity (SYBR-14/PI), mitochondrial function (Rhodamine 123) and acrosome integrity (NAR), were monitored. Overall sperm motility and the individual kinematic parameters of motile spermatozoa (assessed by the computer-aided sperm analysis system Sperm Class Analyzer [SCA]) were recorded in the different experimental treatments. Measurements were taken at 30 and 150 min post-thaw. The state of the acrosome after thawing did not show significant differences between the freezing extenders studied. Freezing-thawing caused a significant decrease (Pextenders. Furthermore, spermatozoa frozen with Orvus ES Paste in both freezing extenders exhibited lower (Pextender. The spermatozoa frozen with the Lactose extender and with Orvus ES Paste only in the second freezing extender showed a better evolution of the motility and kinematic characteristics (Pextenders studied in the present experiment affected the quality of frozen-thawed semen in Iberian boar.

  20. Freezing and desiccation tolerance in entomopathogenic nematodes: diversity and correlation of traits.

    Science.gov (United States)

    Shapiro-Ilan, David I; Brown, Ian; Lewis, Edwin E

    2014-03-01

    The ability of entomopathogenic nematodes to tolerate environmental stress such as desiccating or freezing conditions, can contribute significantly to biocontrol efficacy. Thus, in selecting which nematode to use in a particular biocontrol program, it is important to be able to predict which strain or species to use in target areas where environmental stress is expected. Our objectives were to (i) compare inter- and intraspecific variation in freeze and desiccation tolerance among a broad array of entomopathogenic nematodes, and (ii) determine if freeze and desiccation tolerance are correlated. In laboratory studies we compared nematodes at two levels of relative humidity (RH) (97% and 85%) and exposure periods (24 and 48 h), and nematodes were exposed to freezing temperatures (-2°C) for 6 or 24 h. To assess interspecific variation, we compared ten species including seven that are of current or recent commercial interest: Heterorhabditis bacteriophora (VS), H. floridensis, H. georgiana, (Kesha), H. indica (HOM1), H. megidis (UK211), Steinernema carpocapsae (All), S. feltiae (SN), S. glaseri (VS), S. rarum (17C&E), and S. riobrave (355). To assess intraspecific variation we compared five strains of H. bacteriophora (Baine, Fl1-1, Hb, Oswego, and VS) and four strains of S. carpocapsae (All, Cxrd, DD136, and Sal), and S. riobrave (355, 38b, 7-12, and TP). S. carpocapsae exhibited the highest level of desiccation tolerance among species followed by S. feltiae and S. rarum; the heterorhabditid species exhibited the least desiccation tolerance and S. riobrave and S. glaseri were intermediate. No intraspecific variation was observed in desiccation tolerance; S. carpocapsae strains showed higher tolerance than all H. bacteriophora or S. riobrave strains yet there was no difference detected within species. In interspecies comparisons, poor freeze tolerance was observed in H. indica, and S. glaseri, S. rarum, and S. riobrave whereas H. georgiana and S. feltiae exhibited the

  1. Micromechanical properties of canine femoral articular cartilage following multiple freeze-thaw cycles.

    Science.gov (United States)

    Peters, Abby E; Comerford, Eithne J; Macaulay, Sophie; Bates, Karl T; Akhtar, Riaz

    2017-07-01

    Tissue material properties are crucial to understanding their mechanical function, both in healthy and diseased states. However, in certain circumstances logistical limitations can prevent testing on fresh samples necessitating one or more freeze-thaw cycles. To date, the nature and extent to which the material properties of articular cartilage are altered by repetitive freezing have not been explored. Therefore, the aim of this study is to quantify how articular cartilage mechanical properties, measured by nanoindentation, are affected by multiple freeze-thaw cycles. Canine cartilage plugs (n = 11) from medial and lateral femoral condyles were submerged in phosphate buffered saline, stored at 3-5°C and tested using nanoindentation within 12h. Samples were then frozen at -20°C and later thawed at 3-5°C for 3h before material properties were re-tested and samples re-frozen under the same conditions. This process was repeated for all 11 samples over three freeze-thaw cycles. Overall mean and standard deviation of shear storage modulus decreased from 1.76 ± 0.78 to 1.21 ± 0.77MPa (p = 0.91), shear loss modulus from 0.42 ± 0.19 to 0.39 ± 0.17MPa (p=0.70) and elastic modulus from 5.13 ± 2.28 to 3.52 ± 2.24MPa (p = 0.20) between fresh and three freeze-thaw cycles respectively. The loss factor increased from 0.31 ± 0.38 to 0.71 ± 1.40 (p = 0.18) between fresh and three freeze-thaw cycles. Inter-sample variability spanned as much as 10.47MPa across freezing cycles and this high-level of biological variability across samples likely explains why overall mean "whole-joint" trends do not reach statistical significance across the storage conditions tested. As a result multiple freeze-thaw cycles cannot be explicitly or statistically linked to mechanical changes within the cartilage. However, the changes in material properties observed herein may be sufficient in magnitude to impact on a variety of clinical and scientific studies of cartilage, and should be considered

  2. Influence of Freeze-Thaw Damage on the Steel Corrosion and Bond-Slip Behavior in the Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Fangzhi Zhu

    2016-01-01

    Full Text Available This paper mainly studies the behavior of steel corrosion in various reinforced concrete under freeze-thaw environment. The influence of thickness of concrete cover is also discussed. Additionally, the bond-slip behavior of the reinforced concrete after suffering the freeze-thaw damage and steel corrosion has also be presented. The results show that the freeze-thaw damage aggravates the steel corrosion in concrete, and the results become more obvious in the concrete after suffering serious freeze-thaw damage. Compared with the ordinary concrete, both air entrained concrete and waterproofing concrete possess better resistance to steel corrosion under the same freeze-thaw environment. Moreover, increasing the thicknesses of concrete cover is also an effective method of improving the resistance to steel corrosion. The bond-slip behavior of reinforced concrete with corroded steel decreases with the increase of freeze-thaw damage, especially for the concrete that suffered high freeze-thaw cycles. Moreover, there exists a good correlation between the parameters of bond-slip and freeze-thaw cycles. The steel corrosion and bond-slip behavior of reinforced concrete should be considered serious under freeze-thaw cycles environment, which significantly impact the durability and safety of concrete structure.

  3. Effect of moisture and freeze-thaw on mechanical properties of CRM asphalt mixture

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nak-Seok; Cho, Kee-Ju [Kyonggi University, Suwon(Korea)

    2000-06-30

    This paper presents the experimental test results on moisture and freeze-thaw resistance of hot mix crumb rubber modified (CRM) asphalt concrete mixture. To compare the differences in mechanical properties of conventional and CRM asphalt concretes, various tests were conducted under different moisture conditions and freeze-thaw cycles. Marshall mix design was also performed to determine the optimum asphalt contents for the both asphalt concrete mixtures. Test results revealed that the moisture and freeze-thaw resistance of CRM asphalt mixture was superior to the conventional asphalt concrete. As a result, it is considered that the utilization of waste tires in asphalt pavements has the potential of minimizing the damage due to the moisture and freeze-thaw. (author). 9 refs., 4 tabs., 8 figs.

  4. A model of freezing foods with liquid nitrogen using special functions

    Science.gov (United States)

    Rodríguez Vega, Martín.

    2014-05-01

    A food freezing model is analyzed analytically. The model is based on the heat diffusion equation in the case of cylindrical shaped food frozen by liquid nitrogen; and assuming that the thermal conductivity of the cylindrical food is radially modulated. The model is solved using the Laplace transform method, the Bromwich theorem, and the residue theorem. The temperature profile in the cylindrical food is presented as an infinite series of special functions. All the required computations are performed with computer algebra software, specifically Maple. Using the numeric values of the thermal and geometric parameters for the cylindrical food, as well as the thermal parameters of the liquid nitrogen freezing system, the temporal evolution of the temperature in different regions in the interior of the cylindrical food is presented both analytically and graphically. The duration of the liquid nitrogen freezing process to achieve the specified effect on the cylindrical food is computed. The analytical results are expected to be of importance in food engineering and cooking engineering. As a future research line, the formulation and solution of freezing models with thermal memory is proposed.

  5. High-definition infrared thermography of ice nucleation and propagation in wheat under natural frost conditions and controlled freezing.

    Science.gov (United States)

    Livingston, David P; Tuong, Tan D; Murphy, J Paul; Gusta, Lawrence V; Willick, Ian; Wisniewski, Micheal E

    2018-04-01

    An extremely high resolution infrared camera demonstrated various freezing events in wheat under natural conditions. Many of those events shed light on years of misunderstanding regarding freezing in small grains. Infrared thermography has enhanced our knowledge of ice nucleation and propagation in plants through visualization of the freezing process. The majority of infrared analyses have been conducted under controlled conditions and often on individual organs instead of whole plants. In the present study, high-definition (1280 × 720 pixel resolution) infrared thermography was used under natural conditions to visualize the freezing process of wheat plants during freezing events in 2016 and 2017. Plants within plots were found to freeze one at a time throughout the night and in an apparently random manner. Leaves on each plant also froze one at a time in an age-dependent pattern with oldest leaves freezing first. Contrary to a common assumption that freezing begins in the upper parts of leaves; freezing began at the base of the plant and spread upwards. The high resolution camera used was able to verify that a two stage sequence of freezing began within vascular bundles. Neither of the two stages was lethal to leaves, but a third stage was demonstrated at colder temperatures that was lethal and was likely a result of dehydration stress; this stage of freezing was not detectable by infrared. These results underscore the complexity of the freezing process in small grains and indicate that comprehensive observational studies are essential to identifying and selecting freezing tolerance traits in grain crops.

  6. Globally important nitrous oxide emissions from croplands induced by freeze-thaw cycles

    NARCIS (Netherlands)

    Wagner-Riddle, Claudia; Congreves, Katelyn A.; Abalos Rodriguez, Diego; Berg, Aaron A.; Brown, Shannon E.; Ambadan, Jaison Thomas; Gao, Xiaopeng; Tenuta, Mario

    2017-01-01

    Seasonal freezing induces large thaw emissions of nitrous oxide, a trace gas that contributes to stratospheric ozone destruction and atmospheric warming. Cropland soils are by far the largest anthropogenic source of nitrous oxide. However, the global contribution of seasonal freezing to nitrous

  7. Atmospheric freeze drying assisted by power ultrasound

    International Nuclear Information System (INIS)

    Santacatalina, J V; Cárcel, J A; Garcia-Perez, J V; Mulet, A; Simal, S

    2012-01-01

    Atmospheric freeze drying (AFD) is considered an alternative to vacuum freeze drying to keep the quality of fresh product. AFD allows continuous drying reducing fix and operating costs, but presents, as main disadvantage, a long drying time required. The application of power ultrasound (US) can accelerate AFD process. The main objective of the present study was to evaluate the application of power ultrasound to improve atmospheric freeze drying of carrot. For that purpose, AFD experiments were carried out with carrot cubes (10 mm side) at constant air velocity (2 ms −1 ), temperature (−10°C) and relative humidity (10%) with (20.5 kWm −3 ,USAFD) and without (AFD) ultrasonic application. A diffusion model was used in order to quantify the influence of US in drying kinetics. To evaluate the quality of dry products, rehydration capacity and textural properties were determined. The US application during AFD of carrot involved the increase of drying rate. The effective moisture diffusivity identified in USAFD was 73% higher than in AFD experiments. On the other hand, the rehydration capacity was higher in USAFD than in AFD and the hardness of dried samples did not show significant (p<0.05) differences. Therefore, US application during AFD significantly (p<0.05) sped-up the drying process preserving the quality properties of the dry product.

  8. Dynamical Dark Matter from thermal freeze-out

    Science.gov (United States)

    Dienes, Keith R.; Fennick, Jacob; Kumar, Jason; Thomas, Brooks

    2018-03-01

    In the Dynamical Dark-Matter (DDM) framework, the dark sector comprises a large number of constituent dark particles whose individual masses, lifetimes, and cosmological abundances obey specific scaling relations with respect to each other. In particular, the most natural versions of this framework tend to require a spectrum of cosmological abundances which scale inversely with mass, so that dark-sector states with larger masses have smaller abundances. Thus far, DDM model-building has primarily relied on nonthermal mechanisms for abundance generation such as misalignment production, since these mechanisms give rise to abundances that have this property. By contrast, the simplest versions of thermal freeze-out tend to produce abundances that increase, rather than decrease, with the mass of the dark-matter component. In this paper, we demonstrate that there exist relatively simple modifications of the traditional thermal freeze-out mechanism which "flip" the resulting abundance spectrum, producing abundances that scale inversely with mass. Moreover, we demonstrate that a far broader variety of scaling relations between lifetimes, abundances, and masses can emerge through thermal freeze-out than through the nonthermal mechanisms previously considered for DDM ensembles. The results of this paper thus extend the DDM framework into the thermal domain and essentially allow us to "design" our resulting DDM ensembles at will in order to realize a rich array of resulting dark-matter phenomenologies.

  9. Freezing pattern and frost killing temperature of apple (Malus domestica) wood under controlled conditions and in nature.

    Science.gov (United States)

    Pramsohler, Manuel; Hacker, Jürgen; Neuner, Gilbert

    2012-07-01

    The freezing pattern and frost killing temperatures of apple (Malus domestica Borkh.) xylem were determined by differential thermal analysis and infrared differential thermal analysis (IDTA). Results from detached or attached twigs in controlled freezing experiments and during natural field freezing of trees were compared. Non-lethal freezing of apoplastic water in apple xylem as monitored during natural winter frosts in the field occurred at -1.9 ± 0.4 °C and did not change seasonally. The pattern of whole tree freezing was variable and specific to the environmental conditions. On detached twigs high-temperature freezing exotherms (HTEs) occurred 2.8 K below the temperature observed under natural frosts in the field with a seasonal mean of -4.7 ± 0.5 °C. Microporous apple xylem showed freezing without a specific pattern within a few seconds in IDTA images during HTEs, which is in contrast to macroporous xylem where a 2D freezing pattern mirrors anatomical structures. The pith tissue always remained unfrozen. Increasing twig length increased ice nucleation temperature; for increased twig diameter the effect was not significant. In attached twigs frozen in field portable freezing chambers, HTEs were recorded at a similar mean temperature (-4.6 ± 1.0 °C) to those for detached twigs. Upon lethal intracellular freezing of apple xylem parenchyma cells (XPCs) low-temperature freezing exotherms (LTEs) can be recorded. Low-temperature freezing exotherms determined on detached twigs varied significantly between a winter minimum of -36.9 °C and a summer maximum -12.7 °C. Within the temperature range wherein LTEs were recorded by IDTA in summer (-12.7 ± 0.5 to -20.3 ± 1.1 °C) various tiny clearly separated discontinuous freezing events could be detected similar to that in other species with contrasting XPC anatomy. These freezing events appeared to be initially located in the primary and only later in the secondary xylem. During the LTE no

  10. Serum sample levels of bromine, iron, scandium and zinc in preschool children of Atayal and Bunun aborigines living in central Taiwan

    International Nuclear Information System (INIS)

    Chien-Yi Chen; Ding-Bang Lin; Yuan-Yaw Wei

    2006-01-01

    This study determined bromine, iron, scandium and zinc serum levels in Taiwanese aboriginal preschool children living in remote mountainous areas to increase the understanding of the social, cultural, nutrient and ethnic background of the Taiwanese children. Seventy-three serum samples were taken from two ethnic groups of preschool children, Atayal aborigines (AAPC) and Bunun aborigines (BAPC). Sera of these children were freeze dried. Trace elements in sera were identified by instrumental neutron activation analysis (INAA). The accuracy and precision of INAA was evaluated using certified reference materials: Tomato Leaves (NIST-SRM 1570a) and Lichen (IAEA-336). Statistical analysis identified several different patterns for ethnic groups, gender and age via the two-tailed Student's t-test. Analytical results showed that the ranges of Br, Fe, Sc and Zn in sera were somewhat wide. The Zn serum levels (p < 0.05) and Br serum levels (p < 0.01) in the AAPC were significantly lower than those in the BAPC. However, there were no significant differences in Fe or Sc serum levels between the two groups. Analytical results were compared to published data for different counties. This study is the first investigating trace elements in Taiwanese aborigines and can be used to establish a much-needed serum element database. (author)

  11. Effect of particle surface area on ice active site densities retrieved from droplet freezing spectra

    Directory of Open Access Journals (Sweden)

    H. Beydoun

    2016-10-01

    Full Text Available Heterogeneous ice nucleation remains one of the outstanding problems in cloud physics and atmospheric science. Experimental challenges in properly simulating particle-induced freezing processes under atmospherically relevant conditions have largely contributed to the absence of a well-established parameterization of immersion freezing properties. Here, we formulate an ice active, surface-site-based stochastic model of heterogeneous freezing with the unique feature of invoking a continuum assumption on the ice nucleating activity (contact angle of an aerosol particle's surface that requires no assumptions about the size or number of active sites. The result is a particle-specific property g that defines a distribution of local ice nucleation rates. Upon integration, this yields a full freezing probability function for an ice nucleating particle. Current cold plate droplet freezing measurements provide a valuable and inexpensive resource for studying the freezing properties of many atmospheric aerosol systems. We apply our g framework to explain the observed dependence of the freezing temperature of droplets in a cold plate on the concentration of the particle species investigated. Normalizing to the total particle mass or surface area present to derive the commonly used ice nuclei active surface (INAS density (ns often cannot account for the effects of particle concentration, yet concentration is typically varied to span a wider measurable freezing temperature range. A method based on determining what is denoted an ice nucleating species' specific critical surface area is presented and explains the concentration dependence as a result of increasing the variability in ice nucleating active sites between droplets. By applying this method to experimental droplet freezing data from four different systems, we demonstrate its ability to interpret immersion freezing temperature spectra of droplets containing variable particle concentrations. It is shown

  12. An improved model for nucleation-limited ice formation in living cells during freezing.

    Directory of Open Access Journals (Sweden)

    Jingru Yi

    Full Text Available Ice formation in living cells is a lethal event during freezing and its characterization is important to the development of optimal protocols for not only cryopreservation but also cryotherapy applications. Although the model for probability of ice formation (PIF in cells developed by Toner et al. has been widely used to predict nucleation-limited intracellular ice formation (IIF, our data of freezing Hela cells suggest that this model could give misleading prediction of PIF when the maximum PIF in cells during freezing is less than 1 (PIF ranges from 0 to 1. We introduce a new model to overcome this problem by incorporating a critical cell volume to modify the Toner's original model. We further reveal that this critical cell volume is dependent on the mechanisms of ice nucleation in cells during freezing, i.e., surface-catalyzed nucleation (SCN and volume-catalyzed nucleation (VCN. Taken together, the improved PIF model may be valuable for better understanding of the mechanisms of ice nucleation in cells during freezing and more accurate prediction of PIF for cryopreservation and cryotherapy applications.

  13. Experimental and numerical study on frost heave of saturated rock under uniform freezing conditions

    Science.gov (United States)

    Lv, Zhitao; Xia, Caichu; Li, Qiang

    2018-04-01

    A series of freezing experiments are conducted on saturated sandstone and mortar specimens to investigate the frost heave of saturated rock under uniform freezing conditions. The experimental results show that the frost heave of saturated rock is isotropic under uniform freezing conditions. During the freezing process, three stages are observed in the curves of variation of total frost heaving strain versus time: the thermal contraction stage, the frost heaving stage and the steady stage. Moreover, the amount of final stable frost heave first increases and then decreases with decrease in freezing temperature, and the maximum final stable frost heave occurs at different freezing temperature in saturated sandstone and mortar. Furthermore, a coupled thermal-mechanical (TM) model of frost heave of saturated rock is proposed in which a constraint coefficient \\zeta is used to consider the susceptibility of the internal rock grain structure to the expansion of pore ice. Then, numerical simulations are implemented with COMSOL to solve the governing equations of the TM model. Comparisons of the numerical results with the experimental results are performed to demonstrate the reliability of the model. The influences of elastic modulus and porosity on frost heave are also investigated, and the results show that the total frost heaving strain decreases non-linearly with increasing elastic modulus, and the decrease is significant when the elastic modulus is less than 3000 MPa, or approximately five times the elastic modulus of ice. In addition, the total frost heaving strain increases linearly with increasing porosity. Finally, an empirical equation between total frost heaving strain and freezing temperature is proposed and the equation well describes the variation of total frost heaving strain with freezing temperature.

  14. Synthesis and structural evaluation of freeze-cast porous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Douglas F., E-mail: souzadf@outlook.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nunes, Eduardo H.M., E-mail: eduardohmn@gmail.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Pimenta, Daiana S.; Vasconcelos, Daniela C.L. [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nascimento, Jailton F.; Grava, Wilson [Petrobras/CENPES, Avenida Horácio Macedo 950, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ CEP:21941-915 (Brazil); Houmard, Manuel [Department of Materials Engineering and Civil Construction, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 1, sala 3304 (Brazil); Vasconcelos, Wander L., E-mail: wlv@demet.ufmg.br [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil)

    2014-10-15

    In this work we fabricated alumina samples by the freeze-casting technique using tert-butanol as the solvent. The prepared materials were examined by scanning electron microscopy and X-ray microtomography. Next, they were coated with sol–gel silica films by dip-coating. Permeability tests were carried out in order to assess the permeation behavior of the materials processed in this study. We observed that the sintering time and alumina loading showed a remarkable effect on both the structural properties and flexural strength of the freeze-cast samples. Nitrogen adsorption tests revealed that the silica prepared in this study exhibited a microporous structure. It was observed that the presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance by about one order of magnitude. Because of the similar kinetic diameters of nitrogen and carbon dioxide, the CO{sub 2}/N{sub 2} system showed a separation efficiency that was lower than that observed for the He/CO{sub 2} and He/N{sub 2} systems. We noticed that increasing the feed pressure improved the separation capacity of the obtained materials. - Highlights: • Porous alumina samples obtained by the freeze-casting technique • Microporous silica coating prepared by a simple sol–gel dip-coating methodology • Samples examined by SEM, μ-CT, and nitrogen sorption tests • Mechanical tests were carried out in the freeze-cast samples. • The presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance.

  15. Truths and myths of oocyte sensitivity to controlled rate freezing.

    Science.gov (United States)

    Coticchio, G; Bonu, M A; Sciajno, R; Sereni, E; Bianchi, V; Borini, A

    2007-07-01

    The mammalian oocyte is especially sensitive to cryopreservation. Because of its size and physiology, it can easily undergo cell death or sub-lethal damage as a consequence of intracellular ice formation, increase in the concentration of solutes and other undesired effects during the conversion of extracellular water into ice. This has generated the belief that oocyte storage cannot be achieved with the necessary efficiency and safety. However, many concerns raised by oocyte freezing are the result of unproven hypotheses or observations conducted under sometimes inappropriate conditions. For instance, spindle organization can undergo damage under certain freezing conditions but not with other protocols. The controversial suggestion that cryopreservation induces cortical granule discharge and zona pellucida hardening somehow questions the routine use of sperm microinjection. Damage to mouse oocytes caused by solute concentration is well documented but, in the human, there is no solid evidence that modifications of freezing mixtures, to prevent this problem, provide an actual advantage. The hope of developing oocyte cryopreservation as a major IVF option is becoming increasingly realistic, but major efforts are still required to clarify the authentic implications of oocyte cryopreservation at the cellular level and identify freezing conditions compatible with the preservation of viability and developmental ability.

  16. effect of non-volatile solute on the freezing point of malonic acid

    African Journals Online (AJOL)

    DR. AMINU

    with melting point range 134 - 135 OC. It is solid at room temperature with ... MATERIALS AND METHODS. Quality Control. All glass ... The curve usually has three important features; the linear variation of temperature with time, the region where the temperature remains constant for a time values and the region where there ...

  17. Microstructure study of a material on the basis of YSZ obtained be freeze-drying

    International Nuclear Information System (INIS)

    Rizea, A.; Abrudeanu, M.; Petot, C.; Petot Ervas, G.

    2001-01-01

    Freeze-drying is a dehydration proceeding of the products in a frozen state, which is based on the ice sublimation process. It is a method, which leads to a very good homogeneity of the products and it allows obtaining very fine powders, which directs to reducing the sintering temperature. Freeze drying always supposes three stages: - freezing, sublimation and absorption of the residual water. The preparation of ZrO 20.91 Y 2 O 30.09 samples proceeds through the following stages: - a. solution preparation; b. solution spraying (into small droplets in liquid nitrogen); c. freeze drying processing; d. calcination of the freeze dried powder; e. powder compacting; f. sintering at four different temperature. The different structure of samples with different density are characterized on basis of micrographs. The results of these analyses are presented, discussed and explained through the chemical composition of the samples

  18. Cryochemistry: freezing effect on peptide coupling in different organic solutions.

    Science.gov (United States)

    Vajda, T; Szókán, G; Hollósi, M

    1998-06-01

    The freezing effect on peptide coupling in organic solutions of different polarity has been investigated and compared with the results obtained in liquid phase. The model reaction of DCC-activated coupling of Boc-Ala-Phe-OH with H-Ala-OBu(t) has been carried out in dioxane, dimethylsulfoxide and formamide, as well as in mixtures (90%/10%, v/v) of dioxane with acetonitrile, dimethylformamide, dimethylsulfoxide and formamide. The reactions have been traced and evaluated by RP-HPLC analysis. Freezing the reaction mixture resulted in all cases in a significant suppression of the N-dipeptidylurea side-product formation together with a slight decrease of tripeptide epimerization. The coupling yields and the side effects depended on the solvent, with the dioxane and dioxane/acetonitrile mixture produced the best results. The role of freezing and solvent in the improved results is discussed.

  19. Method of reprocessing nuclear fuel using vacuum freeze-drying method

    International Nuclear Information System (INIS)

    Otsuka, Katsuyuki; Kondo, Isao.

    1989-01-01

    Solutions of plutonium nitrate and uranyl nitrate, spent solvents and liquid wastes separated by the treatment in the solvent extractant steps in the wet processing steps of re-processing plants or fuel fabrication plants are processed by means of freeze-drying under vacuum. Then, the solutions of plutonium nitrate and uranyl nitrate are separated into nitrates and liquid condensates and the spent solvents are freeze-dried. Thus, they are separated into tri-n-butyl phosphate, diester, monoester and n-dodecane and the liquid wastes are processed by means of freeze-drying and separated into liquids and residues. In this way, since sodium carbonate, etc. are not used, the amount of resultant liquid wastes is reduced and sodium is not contained in liquid wastes sent to an asphalt solidification step and a vitrification step, the processing steps can be simplified. (S.T.)

  20. Accelerated storage testing of freeze-dried Pseudomonas ...

    African Journals Online (AJOL)

    Accelerated storage testing of freeze-dried Pseudomonas fluorescens BTP1, ... of all P. fluorescens strains were not significantly different and thermal inactivation ... useful to the development of improved reference materials and samples held ...

  1. Structural Changes in Cattle Immature Oocytes Subjected to Slow Freezing and Vitrification

    Directory of Open Access Journals (Sweden)

    H. Wahid*, M. Thein1, E.A. El-Hafez2, M.O. Abas3, K. Mohd Azam4, O. Fauziah5, Y. Rosnina and H. Hajarian

    2012-05-01

    Full Text Available This study was conducted to evaluate the effect of different cryopreservation methods (slow-freezing and vitrification on structural changes of bovine immature oocytes. Bovine ovaries were collected from local abattoirs. Cumulus-oocyte-complexes (COCs were retrieved using aspiration method from 2-6 mm follicles. In Experiment 1, selected oocytes were randomly divided into 4 treatment groups namely freezing solution-exposed, frozen-thawed, vitrification solution-exposed and vitrified-thawed and then oocytes abnormalities were examined under a stereomicroscope. In Experiment 2, oocytes were randomly allocated to the same grouping as experiment 1 plus control group. Following freezing or vitrification, all oocytes were fixed in glutaraldehyde and processed for transmission electron microscopy. In experiment 1, there was a higher incidence of abnormalities in the frozen-thawed and vitrified-warmed oocytes compared to those in freezing solution and vitrification solution-exposed groups (P<0.05. In experiment 2, there were marked alterations in the perivitelline space, microvilli and vesicles of frozen-thawed and vitrified-warmed oocytes characterized by loss of elasticity and integrity of cytoplasmic processes and microvilli following cooling and warming. In conclusion, ethylene glycol-based freezing and vitrification solutions are suitable choices for cryopreservation of immature oocytes and most organelles are able to retain their normal morphology following cryopreservation and thawing processes.

  2. Application of one-sided stress wave velocity measurement technique to evaluate freeze-thaw damage in concrete

    International Nuclear Information System (INIS)

    Lee, Joon Hyun; Park, Won Su

    1998-01-01

    It is well recognized that damage resulting from freeze-thaw cycles is a serious problems causing deterioration and degradation of concrete. In general, freeze-thaw cycles change the microstructure of the concrete ultimately leading to internal stresses and cracking. In this study, a new method for one-sided stress wave velocity measurement has been applied to evaluate freeze-thaw damage in concrete by monitoring the velocity change of longitudinal and surface waves. The freeze-thaw damage was induced in a 400 x 150 x 100 mm concrete specimen in accordance with ASTM C666 using s commercial testing apparatus. A cycle consisted of a variation of the temperature from -14 to 4 degrees Celsius. A cycle takes 4-5 hours with approximately equal times devoted to freezing-thawing. Measurement of longitudinal and surface wave velocities based on one-sided stress wave velocity measurement technique was made every 5 freeze-thaw cycle. The variation of longitudinal and surface wave velocities due to increasing freeze-thaw damage is demonstrated and compared to determine which one is more effective to monitor freeze-thaw cyclic damage progress. The variation in longitudinal wave velocity measured by one-sided technique is also compared with that measured by the conventional through transmission technique.

  3. Freeze-In dark matter with displaced signatures at colliders

    International Nuclear Information System (INIS)

    Co, Raymond T.; D’Eramo, Francesco; Hall, Lawrence J.; Pappadopulo, Duccio

    2015-01-01

    Dark matter, X, may be generated by new physics at the TeV scale during an early matter-dominated (MD) era that ends at temperature T R ≪ TeV. Compared to the conventional radiation-dominated (RD) results, yields from both Freeze-Out and Freeze-In processes are greatly suppressed by dilution from entropy production, making Freeze-Out less plausible while allowing successful Freeze-In with a much larger coupling strength. Freeze-In is typically dominated by the decay of a particle B of the thermal bath, B→X. For a large fraction of the relevant cosmological parameter space, the decay rate required to produce the observed dark matter abundance leads to displaced signals at LHC and future colliders, for any m X in the range keV

  4. Freezing of liquid alkali metals as screened ionic plasmas

    International Nuclear Information System (INIS)

    Badirkhan, Z.; Rovere, M.; Tosi, M.P.

    1990-08-01

    The relationship between Wigner crystallization of the classical ionic plasma and the liquid-solid transition of alkali metals is examined within the density wave theory of freezing. Freezing of the classical plasma on a rigid neutralizing background into the bcc structure is first re-evaluated, in view of recent progress in the determination of its thermodynamic functions by simulation and of the known difficulties of the theory relating to the order parameter at the (200) star of reciprocal lattice vectors. Freezing into the fcc structure is also considered in this context and found to be unfavoured. On allowing for long-wavelength deformability of the background, the ensuing appearance of a volume change on freezing into the bcc structure is accompanied by reduced stability of the fluid phase and by an increase in the entropy of melting. Freezing of alkali metals into the bcc structure is next evaluated, taking their ionic pair structure as that of an ionic plasma reference fluid screened by conduction electrons and asking that the correct ionic coupling strength at liquid-solid coexistence should be approximately reproduced. The ensuring values of the volume and entropy changes across the phase transition, as estimated from the theory by two alternative routes, are in reasonable agreement with experiment. The order parameters of the phase transition, excepting the (200) one, conform rather closely to a Gaussian behaviour and yield a Lindemann ratio in reasonable agreement with the empirical value for melting of bcc crystals. It is suggested that ionic ordering at the (200) star in the metal may be (i) assisted by medium range ordering in the conduction electrons, as indicated by differences in X-ray and neutron diffraction intensities from the liquid, and/or (ii) quite small in the hot bcc solid. Such a possible premelting behaviour of bcc metals should be worth testing experimentally by diffraction. (author). 48 refs, 1 fig., 1 tab

  5. Development of freeze-dried miyeokguk, Korean seaweed soup, as space food sterilized by irradiation

    Science.gov (United States)

    Song, Beom-Seok; Park, Jin-Gyu; Kim, Jae-Hun; Choi, Jong-Il; Ahn, Dong-Hyun; Hao, Chen; Lee, Ju-Woon

    2012-08-01

    The purpose of this study was to evaluate microbial populations, Hunter's color values (L*, a*, b*) and the sensory quality of freeze-dried miyeokguk, Korean seaweed soup, in order to use it as space food. Microorganisms were not detected in non-irradiated freeze-dried miyeokguk within the detection limit of 1.00 log CFU/g. However, the microbial population in rehydrated miyeokguk was 7.01 log CFU/g after incubation at 35 °C for 48 h, indicating that freeze-dried miyeokguk was not sterilized by heat treatment during the preparation process. Bacteria in the freeze-dried miyeokguk were tentatively identified as Bacillus cereus, B. subtilis, Enterobacter hormaechei, and Ancinetobacter genomosp. using the 16S rDNA sequencing. In samples that were gamma-irradiated above 10 kGy, it was confirmed that all microorganisms were inactivated. Hunter's color values of the samples irradiated at doses less than 10 kGy were not significantly altered from their baseline appearance (p>0.05). Sensory evaluation showed that preference scores in all sensory properties decreased when freeze-dried miyeokguk was irradiated at doses greater than 10 kGy. Therefore, the results of this study suggest that gamma irradiation at 10 kGy is sufficient to sterilize freeze-dried miyeokguk without significant deterioration in the sensory quality, and thus, the freeze-dried and irradiated miyeokguk at 10 kGy fulfills the microbiological requirements as space food.

  6. Controlled cooling versus rapid freezing of teratozoospermic semen samples: Impact on sperm chromatin integrity

    Directory of Open Access Journals (Sweden)

    Shivananda N Kalludi

    2011-01-01

    Full Text Available Aim: The present study evaluates the impact of controlled slow cooling and rapid freezing techniques on the sperm chromatin integrity in teratozoospermic and normozoospermic samples. Setting: The study was done in a university infertility clinic, which is a tertiary healthcare center serving the general population. Design: It was a prospective study designed in vitro. Materials and Methods: Semen samples from normozoospermic (N=16 and teratozoospermic (N=13 infertile men were cryopreserved using controlled cooling and rapid freezing techniques. The sperm chromatin integrity was analyzed in fresh and frozen-thawed samples. Statistical Analysis Used: Data were reported as mean and standard error (mean ± SEM of mean. The difference between two techniques was determined by a paired t-test. Results: The freeze-thaw induced chromatin denaturation was significantly (P<0.01 elevated in the post-thaw samples of normozoospermic and teratozoospermic groups. Compared to rapid freezing, there was no difference in the number of red sperms (with DNA damage by the controlled slow cooling method in both normozoospermic and teratozoospermic groups. Freeze-thaw induced sperm chromatin denaturation in teratozoospermic samples did not vary between controlled slow cooling and rapid freezing techniques. Conclusions: Since the controlled slow cooling technique involves the use of expensive instrument and is a time consuming protocol, rapid freezing can be a good alternative technique for teratozoospermic and normozoospermic samples when sperm DNA damage is a concern.

  7. Chemical freeze-out study in proton-proton collisions at RHIC and LHC energies

    International Nuclear Information System (INIS)

    Das, Sabita; Mishra, Debadeepti; Mohanty, Bedangadas; Chatterjee, Sandeep

    2016-01-01

    Particle multiplicities measured at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) facilities can be used to understand the chemical freeze-out dynamics. At chemical freeze-out (CFO), inelastic collisions cease and the freeze-out parameters can be determined using measured particle multiplicities within the framework of a statistical model. The statistical model has proven to be quite successful in describing the particle production from elementary p-p and e"+e"- collisions up to heavy-ion collisions. It helps to do a systematic study of the centrality and energy dependence of freeze-out parameters in heavy-ion collisions from lower SPS to higher LHC energies. The new data at LHC along with the RHIC data can be used to do such a systematic study in proton-proton collisions

  8. Response surface optimization of lyoprotectant for Lactobacillus bulgaricus during vacuum freeze-drying.

    Science.gov (United States)

    Chen, He; Chen, Shiwei; Li, Chuanna; Shu, Guowei

    2015-01-01

    The individual and interactive effects of skimmed milk powder, lactose, and sodium ascorbate on the number of viable cells and freeze-drying survival for vacuum freeze-dried powder formulation of Lactobacillus bulgaricus were studied by response surface methodology, and the optimal compound lyoprotectant formulations were gained. It is shown that skim milk powder, lactose, and sodium ascorbate had a significant impact on variables and survival of cultures after freeze-drying. Also, their protective abilities could be enhanced significantly when using them as a mixture of 28% w/v skim milk, 24% w/v lactose, and 4.8% w/v sodium ascorbate. The optimal freeze-drying survival rate and the number of viable cells of Lactobacillus bulgaricus were observed to be (64.41±0.02)% and (3.22±0.02)×10(11) colony-forming units (CFU)/g using the optimal compound protectants, which were very close to the expected values 64.47% and 3.28×10(11) CFU/g.

  9. Freezing temperatures as a limit to forest recruitment above tropical Andean treelines.

    Science.gov (United States)

    Rehm, Evan M; Feeley, Kenneth J

    2015-07-01

    The elevation of altitudinal treelines is generally believed to occur where low mean temperatures during the growing season limit growth and prevent trees from establishing at higher elevations. Accordingly, treelines should move upslope with increasing global temperatures. Contrary to this prediction, tropical treelines have remained stable over the past several decades despite increasing mean temperatures. The observed stability of tropical treelines, coupled with the drastically different temperature profiles between temperate and tropical treelines, suggests that using mean measures of temperature to predict tropical treeline movements during climate change may be overly simplistic. We hypothesize that frost events at tropical treelines may slow climate driven treeline movement by preventing tree recruitment beyond the established forest canopy. To assess this hypothesis, we measured freezing resistance of four canopy-forming treeline species (Weinmannia fagaroides, Polylepis pauta, Clethra cuneata, and Gynoxys nitida) at two life stages (juvenile and adult) and during two seasons (warm-wet and cold-dry). Freezing resistances were then compared to microclimatic data to determine if freezing events in the grassland matrix above treeline are too harsh for these forest species. Freezing resistance varied among species and life stages from -5.7 degrees C for juveniles of P. pauta to -11.1 degrees C for juveniles of W. fagaroides. Over a four-year period, the lowest temperatures recorded at 10 cm above ground level in the grasslands above treeline and at treeline itself were -8.9 degrees C and -6.8 degrees C, respectively. Juveniles maintained freezing resistances similar to adults during the coldest parts of the year and ontogenetic differences in freezing resistance were only present during the warm season when temperatures did not represent a significant threat to active plant tissue. These findings support the hypothesis that rare extreme freezing events at and

  10. Fast-freezing with liquid nitrogen preserves bulk dissolved organic matter concentrations, but not its composition

    DEFF Research Database (Denmark)

    Thieme, Lisa; Graeber, Daniel; Kaupenjohann, Martin

    2016-01-01

    -freezing with liquid nitrogen) on DOM concentrations measured as organic carbon (DOC) concentrations and on spectroscopic properties of DOM from different terrestrial ecosystems (forest and grassland). Fresh and differently frozen throughfall, stemflow, litter leachate and soil solution samples were analyzed for DOC...... concentrations, UV-vis absorption and fluorescence excitation–emission matrices combined with parallel factor analysis (PARAFAC). Fast-freezing with liquid nitrogen prevented a significant decrease of DOC concentrations observed after freezing at −18 °C. Nonetheless, the share of PARAFAC components 1 (EXmax...... component 4 (EXmax: 280 nm, EXmax: 328 nm) to total fluorescence was not affected by freezing. We recommend fast-freezing with liquid nitrogen for preservation of bulk DOC concentrations of samples from terrestrial sources, whereas immediate measuring is preferable to preserve spectroscopic properties...

  11. Quantitation of 14C-oxaliplatin concentrations in human serum samples by using accelerator mass spectrometry

    International Nuclear Information System (INIS)

    Kobayashi, Takeshi; Toyoguchi, Teiko; Kato, Kazuhiro; Tokanai, Fuyuki; Shiraishi, Tadashi

    2013-01-01

    The understanding of human pharmacokinetics is important for development of new drugs. Microdosing studies have been proposed as means of obtaining human pharmacokinetics information at early stages of drug development. Accelerator mass spectrometry (AMS) has high detection sensitivity and is expected to play an important role in microdose trials. In this study, we used the AMS microdosing facility at Yamagata University to measure the concentration of 14 C in 14 C-oxaliplatin-spiked serum samples. The calibration curve of 14 C concentration in serum was linear, and the correlation coefficient was 0.9994. The precision, accuracy, and stability values obtained (freeze and thaw cycles, and short- and long-term stability) satisfied the criteria. The mean background 14 C concentrations in samples of 6 healthy Japanese volunteers were 1.635dpm/mL in blood and 0.56dpm/mL in plasma. These results suggest the suitability of AMS-based quantitation for analyzing samples from microdosing studies. (author)

  12. Development of Steel Fiber-Reinforced Expanded-Shale Lightweight Concrete with High Freeze-Thaw Resistance

    Directory of Open Access Journals (Sweden)

    Mingshuang Zhao

    2018-01-01

    Full Text Available For the popularized structural application, steel fiber-reinforced expanded-shale lightweight concrete (SFRELC with high freeze-thaw resistance was developed. The experimental study of this paper figured out the effects of air-entraining content, volume fraction of steel fibers, and fine aggregate type. Results showed that while the less change of mass loss rate was taken place for SFRELC after 300 freeze-thaw cycles, the relative dynamic modulus of elasticity and the relative flexural strength presented clear trends of freeze-thaw resistance of SFRELC. The compound effect of the air-entraining agent and the steel fibers was found to support the SFRELC with high freeze-thaw resistance, and the mechanisms were explored with the aid of the test results of water penetration of SFRELC. The beneficial effect was appeared from the replacement of lightweight sand with manufactured sand. Based on the test results, suggestions are given out for the optimal mix proportion of SFRELC to satisfy the durability requirement of freeze-thaw resistance.

  13. Preparation and evaluation of freeze-dried Mag3 kits for 99m Tc-labelling

    International Nuclear Information System (INIS)

    El-Mohty, A.A.; El-Ghany, E.A.; El-Kolaly, M.T.; Raieh, M.; EL-Bary, A.A.

    1996-01-01

    The freeze-dried Mag 3 kits were designed for both ligand trans chelation and direct labelling techniques. The solution of Sn-Mag 3 was sterilized by 0.22 μU mill pore filtration and dispensed in a laminar flow hood (1 m I / vial) then, the vials were introduced to the lyophilized. The process of lyophilization was continued for 24 hours. At end of the cycle, the vials were closed under nitrogen. The moisture content of the freeze-dried Mag 3 kits was determined and it was found equal to 0.1% also, the losses of tin (II) during the freeze-drying cycle did not exceed 5%. It was found that the Mag 3 freeze-dried kits were sterile, pyrogen free and does not have any unexpected toxicity. The prepared Mag 3 freeze-dried kits have high radiochemical purity > 97% and high stability for more than 8 h after labelling. The biodistribution shows rapid renal excretion at 15 min post injection. 3 figs., 4 tabs

  14. Development and commisioning of a test procedure for the investigation of the impact of freeze-thaw cycles on the sealing material of geothermal probes; Entwicklung und Inbetriebnahme eines Pruefverfahrens zur Bestimmung des Frost-Tau-Wechseleinflusses auf das Verpressmaterial von Erdwaermesonden

    Energy Technology Data Exchange (ETDEWEB)

    Anbergen, Hauke [Knabe Enders Duehrkop Ingenieure GmbH, Hamburg (Germany); Technische Univ. Darmstadt (Germany); Frank, Jens [Knabe Enders Duehrkop Ingenieure GmbH, Hamburg (Germany); Sass, Ingo [Technische Univ. Darmstadt (Germany)

    2011-10-24

    In order to exploit the full potential of near-surface geothermal probes, an operation at brine temperatures below the freezing point of water is necessary. This can result in a cyclic freezing and thawing of the surrounding sealing materials. Thus, such a material must have permanently a water permeability below defined limits even after the freeze-thaw stress. For this, test conditions had to be defined, and a measurement method has to be developed. For this purpose, a measuring cell was modified according to DIN 18130 so that freezing processes can be simulated under in-situ conditions using an axially integrated cooling pipe, and the water permeability can be measured as a function of the number of freeze-thaw cycles. The authors of the contribution under consideration report on the test procedure as well as on the results of a complete series of tests.

  15. Effects of Freezing and Thawing Cycle on Mechanical Properties and Stability of Soft Rock Slope

    Directory of Open Access Journals (Sweden)

    Yanlong Chen

    2017-01-01

    Full Text Available To explore the variation laws of mechanical parameters of soft rock and the formed slope stability, an experiment was carried out with collected soft rock material specimens and freezing and thawing cycle was designed. Meanwhile, a computational simulation analysis of the freezing-thawing slope stability was implemented. Key factors that influence the strength of frozen rock specimens were analyzed. Results showed that moisture content and the number of freezing-thawing cycles influenced mechanical parameters of soft rock significantly. With the increase of moisture content, cohesion of frozen soft rock specimens presents a quadratic function decrease and the internal friction angle shows a negative exponential decrease. The stability coefficient of soft rock material slope in seasonal freeze soil area declines continuously. With the increase of freezing and thawing cycle, both cohesion and internal friction angle of soft rock decrease exponentially. The higher the moisture content, the quicker the reduction. Such stability coefficient presents a negative exponential reduction. After three freezing and thawing cycles, the slope stability coefficient only changes slightly. Findings were finally verified by the filed database.

  16. Study the interaction between CdTe-glutathione and human serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Qing; Zhou, Xi-min; Zhu, Yi-shuo [National Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Lanzhou University, Lanzhou 730000 (China); Chen, Xing-guo, E-mail: chenxg@lzu.edu.cn [National Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000 (China); Department of Chemistry, Lanzhou University, Lanzhou 730000 (China)

    2013-03-15

    In this paper, glutathione (GSH) modified CdTe quantum dots (CdTe-GSH QDs) were synthesized in an aqueous solution. Then, the binding of the CdTe-GSH QDs to human serum albumin (HSA) was studied using the fluorescence spectroscopy. The quenching mechanism was investigated in terms of the association constants and basic thermodynamic parameters. The fluorescence data revealed that CdTe-GSH QDs could quench the intrinsic fluorescence of human serum albumin by a static quenching mechanism. Furthermore, alteration of the secondary protein structure in the presence of the QDs was confirmed by synchronous fluorescence spectra. - Highlights: Black-Right-Pointing-Pointer In this paper, the binding of the CdTe-GSH QDs to human serum albumin (HSA) was studied using a fluorescence spectroscopy. Black-Right-Pointing-Pointer The quenching mechanism was investigated in terms of the association constants and basic thermodynamic parameters. Black-Right-Pointing-Pointer Furthermore, alteration of the secondary protein structure in the presence of the QDs was confirmed by synchronous fluorescence spectra. Black-Right-Pointing-Pointer The research can help us assess biological toxicity of QDs and further expand the application scope of QDs.

  17. Warm and cold fermionic dark matter via freeze-in

    International Nuclear Information System (INIS)

    Klasen, Michael; Yaguna, Carlos E.

    2013-01-01

    The freeze-in mechanism of dark matter production provides a simple and intriguing alternative to the WIMP paradigm. In this paper, we analyze whether freeze-in can be used to account for the dark matter in the so-called singlet fermionic model. In it, the SM is extended with only two additional fields, a singlet scalar that mixes with the Higgs boson, and the dark matter particle, a fermion assumed to be odd under a Z 2 symmetry. After numerically studying the generation of dark matter, we analyze the dependence of the relic density with respect to all the free parameters of the model. These results are then used to obtain the regions of the parameter space that are compatible with the dark matter constraint. We demonstrate that the observed dark matter abundance can be explained via freeze-in over a wide range of masses extending down to the keV range. As a result, warm and cold dark matter can be obtained in this model. It is also possible to have dark matter masses well above the unitarity bound for WIMPs

  18. Dark Matter Freeze-in Production in Fast-Expanding Universes

    Science.gov (United States)

    D'Eramo, Francesco; Fernandez, Nicolas; Profumo, Stefano

    2018-02-01

    If the dark matter is produced in the early universe prior to Big Bang nucleosynthesis, a modified cosmological history can drastically affect the abundance of relic dark matter particles. Here, we assume that an additional species to radiation dominates at early times, causing the expansion rate at a given temperature to be larger than in the standard radiation-dominated case. We demonstrate that, if this is the case, dark matter production via freeze-in (a scenario when dark matter interacts very weakly, and is dumped in the early universe out of equilibrium by decay or scattering processes involving particles in the thermal bath) is dramatically suppressed. We illustrate and quantitatively and analytically study this phenomenon for three different paradigmatic classes of freeze-in scenarios. For the frozen-in dark matter abundance to be as large as observations, couplings between the dark matter and visible-sector particles must be enhanced by several orders of magnitude. This sheds some optimistic prospects for the otherwise dire experimental and observational outlook of detecting dark matter produced by freeze-in.

  19. Ice, Ice, Baby? A Sociological Exploration of Social Egg Freezing

    OpenAIRE

    Baldwin, K.

    2016-01-01

    Social egg freezing is a fertility preservation strategy which enables women to preserve a number of healthy unfertilised eggs for potential future use when faced with the threat of age-related fertility decline. The overall aim of this thesis was to explore how women understand, construct and experience social egg freezing in the context of debates surrounding reproductive ‘choice’ and ‘delayed motherhood’. The study sought to provide insights into how women perceive the risks and benefi...

  20. Measuring influenza RNA quantity after prolonged storage or multiple freeze/thaw cycles.

    Science.gov (United States)

    Granados, Andrea; Petrich, Astrid; McGeer, Allison; Gubbay, Jonathan B

    2017-09-01

    In this study, we aim to determine what effects prolonged storage and repeated freeze/thaw cycles have on the stability of influenza A(H1N1)pdm09 (influenza A/H1N1)RNA. Cloned influenza A/H1N1 RNA transcripts were serially diluted from 8.0-1.0 log 10 copies/μl. RT-qPCR was used to measure RNA loss in transcripts stored at -80°C, -20°C, 4°C and 25°C for up to 84days or transcripts undergoing a total of 10 freeze/thaw cycles. Viral load was measured in clinical specimens stored at-80°C for three years (n=89 influenza A RNA extracts; n=35 primary specimens) and in 10 clinical specimens from the 2015/2016 influenza season that underwent 7 freeze/thaw cycles. RNA stored at -80°C, -20°C, 4°C and 25°C is stable for up to 56, 56, 21, and 7days respectively or up to 9 freeze/thaw cycles when stored at -80°C. There is no difference in viral load in clinical specimens that have been stored for up to three years at -80°C if they are re-extracted. Similarly, clinical specimens undergoing up to 7 freeze/thaw cycles are stable if they are re-extracted between cycles. Influenza specimens can be stored for up to three years at -80°C or undergo up to 7 freeze/thaw cycles without loss of RNA quantity if re-extracted. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Determination of psilocin, bufotenine, LSD and its metabolites in serum, plasma and urine by SPE-LC-MS/MS.

    Science.gov (United States)

    Martin, Rafaela; Schürenkamp, Jennifer; Gasse, Angela; Pfeiffer, Heidi; Köhler, Helga

    2013-05-01

    A validated method for the simultaneous determination of psilocin, bufotenine, lysergic acid diethylamide and its metabolites in serum, plasma and urine using liquid chromatography-electrospray ionization/tandem mass spectrometry was developed. During the solid-phase extraction procedure with polymeric mixed-mode cation exchange columns, the unstable analytes were protected by ascorbic acid, drying with nitrogen and exclusion of light. The limits of detection and quantitation for all analytes were low. Recovery was ≥86 % for all analytes and no significant matrix effects were observed. Interday and intraday imprecisions at different concentrations ranged from 1.1 to 8.2 % relative standard deviation, bias was within ±5.3 %. Processed samples were stable in the autosampler for at least 2 days. Furthermore, freeze/thaw and long-term stability were investigated. The method was successfully applied to authentic serum and urine samples.

  2. Effects of rasagiline on freezing of gait in Parkinson's disease - an open-label, multicenter study.

    Science.gov (United States)

    Cibulcik, Frantisek; Benetin, Jan; Kurca, Egon; Grofik, Milan; Dvorak, Miloslav; Richter, Denis; Donath, Vladimir; Kothaj, Jan; Minar, Michal; Valkovic, Peter

    2016-12-01

    Freezing of gait is a disabling symptom in advanced Parkinson's disease. Positive effects have been suggested with MAO-B inhibitors. We report on an open label clinical study on the efficacy of rasagiline as add-on therapy on freezing of gait and quality of life in patients with Parkinson's disease. Forty two patients with freezing of gait were treated with 1 mg rasagiline daily as an add-on therapy. Patients were assessed at baseline and after 1, 2 and 3 months of treatment. Freezing of gait severity was assessed using the Freezing of Gait Questionnaire, motor impairment by the modified MDS UPDRS part III, and quality of life using the PDQ-39 questionnaire. Patients treated with rasagiline had a statistically significant decrease in FoG-Q score and modified MDS UPDRS score after 1, 2 and 3 months of therapy. A moderately strong (r = 0.686, P = 0.002) correlation between the effects on mobility and freezing of gait was found. We also observed a statistically significant improvement in global QoL and in the subscales mobility, ADL, stigma and bodily discomfort in patients after 3 months of rasagiline therapy. A significant correlation (r = 0.570, P = 0.02) between baseline FoG-Q score and the baseline score for the PDQ Mobility subscale was found. In our study rasagiline as add-on antiparkinsonian therapy significantly improved mobility, freezing of gait and quality of life. The positive effect on freezing of gait appears to be related to improvement of mobility.

  3. Evaluation of Genotoxicity and 28-day Oral Dose Toxicity on Freeze-dried Powder of Tenebrio molitor Larvae (Yellow Mealworm).

    Science.gov (United States)

    Han, So-Ri; Yun, Eun-Young; Kim, Ji-Young; Hwang, Jae Sam; Jeong, Eun Ju; Moon, Kyoung-Sik

    2014-06-01

    The larval form of Tenebrio molitor (T. molitor) has been eaten in many countries and provides benefits as a new food source of protein for humans. However, no information exists regarding its safety for humans. The objective of the present study was to evaluate the genotoxicity and repeated dose oral toxicity of the freeze-dried powder of T. molitor larvae. The genotoxic potential was evaluated by a standard battery testing: bacterial reverse mutation test, in vitro chromosome aberration test, and in vivo micronucleus test. To assess the repeated dose toxicity, the powder was administered once daily by oral gavage to Sprague-Dawley (SD) rats at dose levels of 0, 300, 1000 and 3000 mg/kg/day for 28 days. The parameters which were applied to the study were mortality, clinical signs, body and organ weights, food consumption, ophthalmology, urinalysis, hematology, serum chemistry, gross findings and histopathologic examination. The freezedried powder of T. molitor larvae was not mutagenic or clastogenic based on results of in vitro and in vivo genotoxicity assays. Furthermore, no treatment-related changes or findings were observed in any parameters in rats after 28 days oral administration. In conclusion, the freeze-dried powder of T. molitor larvae was considered to be non-genotoxic and the NOAEL (No Observed Adverse Effect Level) was determined to be 3000 mg/kg/day in both sexes of SD rats under our experimental conditions.

  4. Drying of α-amylase by spray drying and freeze-drying - a comparative study

    Directory of Open Access Journals (Sweden)

    S. S. de Jesus

    2014-09-01

    Full Text Available This study is aimed at comparing two traditional methods of drying of enzymes and at verifying the efficiency of each one and their advantages and disadvantages. The experiments were performed with a laboratory spray dryer and freeze-dryer using α-amylase as the model enzyme. An experimental design in star revealed that spray drying is mainly influenced by the inlet air temperature and feed flow rate, which were considered to be the main factors influencing the enzymatic activity and water activity; the long period of material exposure to high temperatures causes a partial activity loss. In the experiments of freeze drying, three methods of freezing were used (freezer, acetone and dry ice, and liquid nitrogen and samples subsequently freeze-dried for times ranging between 0-24 hours. The product obtained from the two techniques showed high enzymatic activity and low water activity. For the drying of heat-resistant enzymes, in which the product to be obtained does not have high added value, spray drying may be more economically viable because, in the freeze drying process, the process time can be considered as a limiting factor when choosing a technique.

  5. Effects of the freezing and thawing process on biomechanical properties of the human skull.

    Science.gov (United States)

    Torimitsu, Suguru; Nishida, Yoshifumi; Takano, Tachio; Koizumi, Yoshinori; Hayakawa, Mutsumi; Yajima, Daisuke; Inokuchi, Go; Makino, Yohsuke; Motomura, Ayumi; Chiba, Fumiko; Iwase, Hirotaro

    2014-03-01

    The aim of this study was to determine if biomechanical investigations of skull samples are reliable after skulls have been subjected to a freezing and thawing process. The skulls were obtained from 105 Japanese cadavers (66 males, 39 females) of known age that were autopsied in our department between October 2012 and June 2013. We obtained bone specimens from eight sites (four bilaterally symmetrical pairs) of each skull and measured the mass of each specimen. They were then classified into three groups (A, B, C) based on the duration of freezing of the experimental samples. The left-side samples were subjected to frozen storage (experimental group). The corresponding right-side samples were their controls. Bending tests were performed on the controls immediately after they were obtained. The experimental samples were preserved by refrigeration at -20 °C for 1 day (group A), 1 month (group B), or 3 months (group C). Following refrigeration, these samples were placed at 37 °C to thaw for 1 h and then were subjected to bending tests using a three-point-bending apparatus attached to a Handy force gauge. The device recorded the fracture load automatically when the specimen fractured. Statistical analyses revealed that there were no significant differences in sample fracture loads between the frozen preserved/thawed samples and the unfrozen controls for each of the cryopreservation intervals. We eliminated any possible sample mass bias by using controls from the same skull in each case. The results suggest that the freezing/thawing process has little effect on the mechanical properties of human skulls. Thus, frozen storage for up to 3 months is a good method for preserving human skulls. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. Protoplasmic Swelling as a Symptom of Freezing Injury in Onion Bulb Cells 1

    Science.gov (United States)

    Arora, Rajeev; Palta, Jiwan P.

    1986-01-01

    Freezing injury, in onion bulb tissue, is known to cause enhanced K+ efflux accompanied by a small but significant loss of Ca2+ following incipient freezing injury and swelling of protoplasm during the postthaw secondary injury. The protoplasmic swelling of the cell is thought to be caused by the passive influx of extracellular K+ into the cell followed by water uptake. Using outer epidermal layer of unfrozen onion bulb scales (Allium cepa L. cv Big Red), we were able to stimulate the irreversible freezing injury symptoms, by bathing epidermal cells in 50 millimolar KCl. These symptoms were prevented by adding 20 millimolar CaCl2 to the extracellular KCl solution. Our results provide evidence that loss of cellular Ca2+ plays an important role in the initiation and the progression of freezing injury. Images Fig. 1 PMID:16665083

  7. LASER BIOLOGY AND MEDICINE: Optoacoustic laser monitoring of cooling and freezing of tissues

    Science.gov (United States)

    Larin, Kirill V.; Larina, I. V.; Motamedi, M.; Esenaliev, R. O.

    2002-11-01

    Real-time monitoring of cooling and freezing of tissues, cells, and other biological objects with a high spatial and time resolution, which is necessary for selective destruction of cancer and benign tumours during cryotherapy, as well as for preventing any damage to the structure and functioning of biological objects in cryobiology, is considered. The optoacoustic method, based on the measurement and analysis of acoustic waves induced by short laser pulses, is proposed for monitoring the cooling and freezing of the tissue. The effect of cooling and freezing on the amplitude and time profile of acoustic signals generated in real tissues and in a model object is studied. The experimental results indicate that the optoacoustic laser technique can be used for real-time monitoring of cooling and freezing of biological objects with a submillimeter spatial resolution and a high contrast.

  8. When do particle ratios freeze out in relativistic heavy ion collisions?

    Science.gov (United States)

    Humanic, Thomas; Bellwied, Rene

    1999-10-01

    The systematics of CERN SPS data for transverse mass distributions have been shown to imply that thermal equilibrium is achieved at freeze out in these collisions. This conclusion is based on the observation that for p+p, S+S, and Pb+Pb collisions freeze out occurs at a single temperature for all particle species measured if one assumes a certain uniform expansion velocity after hadronization for each colliding system [1]. A recent final- state rescattering calculation for SPS Pb+Pb collisions has shown that these systematics can be described as a consequence of particle rescattering where the system is assumed initially (i.e. at hadronization) to have a common temperature for all particles and no initial expansion velocity [2]. In addition to kinetic observables, it is equally interesting to investigate the time dependence of particle abundances through particle ratios in such a calculation. Two questions immediately arise: 1) is chemical equilibrium established in these collisions, and 2) when does chemical freeze out occur with respect to thermal freeze out for different particle ratios? How rescattering influences particle ratios is clearly of interest if one would like to deduce information about the hadronization stage of the collision from particle ratios measured at freeze out. For the present work we will show results for strange and non-strange particle ratios within the context of a version of the dynamic transport code used in Ref. [2]. [1] NA44 colaboration, I.G. Bearden et al., Phys. Rev. Lett. 78,2080(1997), [2] T. J. Humanic, Phys. Rev. C 57,866(1998)

  9. Visualization data on the freezing process of micrometer-scaled aqueous citric acid drops

    Directory of Open Access Journals (Sweden)

    Anatoli Bogdan

    2017-02-01

    Full Text Available The visualization data (8 movies presented in this article are related to the research article entitled “Freezing and glass transitions upon cooling and warming and ice/freeze-concentration-solution morphology of emulsified aqueous citric acid” (A. Bogdan, M.J. Molina, H. Tenhu, 2016 [1]. The movies recorded in-situ with optical cryo-miscroscopy (OC-M demonstrate for the first time freezing processes that occur during the cooling and subsequent warming of emulsified micrometer-scaled aqueous citric acid (CA drops. The movies are made publicly available to enable critical or extended analyzes.

  10. Behaviour of polycyclic aromatic hydrocarbons (PAH) in soils under freeze-thaw cycles

    Science.gov (United States)

    Zschocke, Anne; Schönborn, Maike; Eschenbach, Annette

    2010-05-01

    The arctic region will be one of the most affected regions by climate change due to the predicted temperature rise. As a result of anthropogenic actions as mining, exploration and refining as well as atmospheric transport pollutions can be found in arctic soils. Therefore questions on the behaviour of organic contaminants in permafrost influenced soils are of high relevance. First investigations showed that permafrost can act as a semi-permeable layer for PAH (Curtosi et al., 2007). Therefore it can be assumed that global warming could result in a mobilization of PAH in these permafrost influenced soils. On the other hand a low but detectable mineralization of organic hydrocarbons by microorganisms under repeated freeze-thaw cycles was analysed (Börresen et al. 2007, Eschenbach et al. 2000). In this study the behaviour and distribution of PAH under freezing and periodically freezing and thawing were investigated in laboratory column experiments with spiked soil materials. Two soil materials which are typical for artic regions, a organic matter containing melt water sand and a well decomposed peat, were homogeneously spiked with a composite of a crude oil and the PAH anthracene and benzo(a)pyrene. After 14days preincubation time the soil material was filled in the laboratory columns (40cm high and 10 cm in diameter). Based on studies by Chuvilin et al. (2001) the impact of freezing of the upper third of the column from the surface downwards was examined. The impact of freezing was tested in two different approaches the first one with a single freezing step and the second one with a fourfold repeated cycle of freezing and thawing which takes about 6 or 7 days each. The experimental design and very first results will be shown and discussed. In some experiments with the peat a higher concentration of anthracene and benzo(a)pyrene could be detected below the freezing front in the unfrozen part of the column. Whereas the concentration of PAH had slightly decreased in

  11. Control of crystal growth in water purification by directional freeze crystallization

    Science.gov (United States)

    Conlon, William M. (Inventor)

    1996-01-01

    A Directional Freeze Crystallization system employs an indirect contact heat exchanger to freeze a fraction of liquid to be purified. The unfrozen fraction is drained away and the purified frozen fraction is melted. The heat exchanger must be designed in accordance with a Growth Habit Index to achieve efficient separation of contaminants. If gases are dissolved in the liquid, the system must be pressurized.

  12. A Peltier-based freeze-thaw device for meteorite disaggregation

    Science.gov (United States)

    Ogliore, R. C.

    2018-02-01

    A Peltier-based freeze-thaw device for the disaggregation of meteorite or other rock samples is described. Meteorite samples are kept in six water-filled cavities inside a thin-walled Al block. This block is held between two Peltier coolers that are automatically cycled between cooling and warming. One cycle takes approximately 20 min. The device can run unattended for months, allowing for ˜10 000 freeze-thaw cycles that will disaggregate meteorites even with relatively low porosity. This device was used to disaggregate ordinary and carbonaceous chondrite regoltih breccia meteorites to search for micrometeoroid impact craters.

  13. The immersion freezing behavior of size-segregated soot and kaolinite particles

    Science.gov (United States)

    Hartmann, S.; Augustin, S.; Clauss, T.; Niedermeier, D.; Raddatz, M.; Wex, H.; Shaw, R. A.; Stratmann, F.

    2011-12-01

    Heterogeneous ice nucleation plays a crucial role for ice formation in mixed-phase and cirrus clouds and has an important impact on precipitation formation, global radiation balances, and therefore Earth's climate (Cantrell and Heymsfield, 2005). Mineral dust and soot particles are found to be a major component of ice crystal residues (e.g., Pratt et al., 2009) so these substances are potential sources of atmospheric ice nuclei (IN). Experimental studies investigating the immersion freezing behavior of size-segregated soot and kaolinite particles conducted at the Leipzig Aerosol Cloud Interaction Simulator (LACIS) are presented. In our measurements only one aerosol particle is immersed in an air suspended water droplet which can trigger ice nucleation. The method facilitates very precise examinations with respect to temperature, ice nucleation time and ice nucleus size. Considering laboratory studies, the picture of the IN ability of soot particles is quite heterogeneous. Our studies show that submicron flame, spark soot particles and optionally coated with sulfuric acid to simulate chemically aging do not act as IN at temperatures higher than homogeneous freezing taking place. Therefore soot particles might not be an important source of IN for immersion freezing in the atmosphere. In contrast, kaolinite being representative for natural mineral dust with a well known composition and structure is found to be very active in forming ice for all freezing modes (e.g., Mason and Maybank, 1958). Analyzing the immersion freezing behavior of different sized kaolinite particles (300, 500 and 700 nm in diameter) the size effect was clearly observed, i.e. the ice fraction (number of frozen droplets per total number) scales with particle surface, i.e. the larger the ice nucleus surface the higher the ice fraction. The slope of the logarithm of the ice fraction as function of temperature is similar for all particle sizes investigated and fits very well with the results of L

  14. Freeze drying reduces the extractability of organochlorine pesticides in fish muscle tissue by microwave-assisted method

    International Nuclear Information System (INIS)

    Zhang, Yanyan; Lin, Nan; Su, Shu; Shen, Guofeng; Chen, Yuanchen; Yang, Chunli; Li, Wei; Shen, Huizhong; Huang, Ye; Chen, Han; Wang, Xilong; Liu, Wenxin; Tao, Shu

    2014-01-01

    Samples of animal origin are usually dried before solvent extraction for analysis of organic contaminants. The freeze drying technique is preferred for hydrophobic organic compounds in practice. In this study, it was shown that the concentration of organochlorine pesticides (OCPs) extracted from fish muscle tissue significantly decreased after the samples were freeze dried. And the reason for this reduced extractability seemed to be the resistance of OCPs associated with freeze-dried muscle protein to solvent extraction. The extractability can be recovered by adding water prior to extraction. It suggests that the dietary exposure risk of OCPs from fish might be underestimated if freeze-dried samples are used. - Highlights: • Freeze drying significantly reduces extractability of OCPs in fish muscle sample. • It is the protein that causes the reduction in extractability of OCPs. • The extractability can be recovered by adding water before extraction. - Freeze drying significantly decreases the concentrations of OCPs extracted from fish muscle samples by microwave-assisted method

  15. Degradation of ATP and glycogen in cod ( Gadus morhua ) muscle during freezing

    DEFF Research Database (Denmark)

    Cappeln, Gertrud; Jessen, Flemming

    2001-01-01

    , the greatest decrease in ATP content was observed when the temperature reached -0.8C. Glycolysis occurred during freezing of cod as indicated by an increase in lactate content. The changes found in all measured metabolites were more pronounced when freezing was performed at a slow rate compared to a fast rate...

  16. Behavior of Plain Concrete of a High Water-Cement Ratio after Freeze-Thaw Cycles

    OpenAIRE

    Shang, Huai-Shuai; Yi, Ting-Hua; Song, Yu-Pu

    2012-01-01

    An experimental study of plain concrete specimens of water-cement ratio 0.55, subjected to 0, 15, 25, 40, 50 and 75 cycles of freeze-thaw was completed. The dynamic modulus of elasticity (DME), weight loss, compressive strength, tensile strength, flexural strength, cleavage strength and stress-strain relationships of plain concrete specimens suffering from freeze-thaw cycles were measured. The experimental results showed that the strength decreased as the freeze-thaw cycles were repeated. A c...

  17. Viability of G4 after Spray-Drying and Freeze-Drying

    Directory of Open Access Journals (Sweden)

    Stephenie Wong

    2010-01-01

    Full Text Available Viability of Bifidobacterium pseudocatenulatum G4 following spray-drying and freeze-drying in skim milk was evaluated. After spray-drying, the strain experienced over 99% loss in viability regardless of the air outlet temperature (75 and 85 °C and the heat-adaptation temperature (45 and 65 °C, 30 min. The use of heat-adaptation treatment to improve the thermotolerance of this strain was ineffective. On the other hand, the strain showed a superior survival at 71.65%–82.07% after freeze-drying. Viable populations of 9.319–9.487 log 10 cfu/g were obtained when different combinations of skim milk and sugar were used as cryoprotectant. However, the addition of sugars did not result in increased survival during the freeze-drying process. Hence, 10% (w/v skim milk alone is recommended as a suitable protectant and drying medium for this strain. The residual moisture content obtained was 4.41% ± 0.44%.

  18. Resilience of Floating Treatment Wetlands to Repeated Freeze-Thaw Cycles

    Science.gov (United States)

    Ortega, K.; Marchetto, P.; Magner, J.

    2017-12-01

    Floating treatment wetlands (FTWs), made of a matrix of recycled polyethylene terephthalate (PET) fibers, are currently being used as a method to reduce nutrient loading in lakes. The matrix encourages growth of biofilms, which uptake nutrients from the water. However, the usefulness of FTWs has only been assessed in areas where the lakes do not freeze over in the winter. Repeated freeze-thaw cycles were run on sections of the FTWs in a laboratory setting in order to test the resilience of the PET fibers over the FTWs' advertised fifteen-year lifespan. Preliminary findings suggest that the stresses caused by freezing and thawing of the surrounding water contribute to deterioration of the PET fibers, leading to production of microplastics. Estimations indicate that approximately 0.063% of a FTW's mass could be lost as microplastics over the course of its lifespan. Production of microplastics contributes to plastic pollution in the treatment water, possibly offsetting any nutrient remediation the FTWs perform.

  19. Drying characteristics of pumpkin ( Cucurbita moschata) slices in convective and freeze dryer

    Science.gov (United States)

    Caliskan, Gulsah; Dirim, Safiye Nur

    2017-06-01

    This study was intended to determine the drying and rehydration kinetics of convective and freeze dried pumpkin slices (0.5 × 3.5 × 0.5 cm). A pilot scale tray drier (at 80 ± 2 °C inlet temperature, 1 m s-1 air velocity) and freeze drier (13.33 kPa absolute pressure, condenser temperature of -48 ± 2 °C) were used for the drying experiments. Drying curves were fitted to six well-known thin layer drying models. Nonlinear regression analysis was used to evaluate the parameters of the selected models by using statistical software SPSS 16.0 (SPSS Inc., USA). For the convective and freeze drying processes of pumpkin slices, the highest R2 values, and the lowest RMSE as well as χ2 values were obtained from Page model. The effective moisture diffusivity (Deff) of the convective and freeze dried pumpkin slices were obtained from the Fick's diffusion model, and they were found to be 2.233 × 10-7 and 3.040 × 10-9 m2s-1, respectively. Specific moisture extraction rate, moisture extraction rate, and specific energy consumption values were almost twice in freeze drying process. Depending on the results, moisture contents and water activity values of pumpkin slices were in acceptable limits for safe storage of products. The rehydration behaviour of [at 18 ± 2 and 100 ± 2 °C for 1:25, 1:50, 1:75, 1:100, and 1:125 solid:liquid ratios (w:w)] dried pumpkin slices was determined by Peleg's model with the highest R2. The highest total soluble solid loss of pumpkin slices was observed for the rehydration experiment which performed at 1:25 solid: liquid ratio (w:w). Rehydration ratio of freeze dried slices was found 2-3 times higher than convective dried slices.

  20. Investigation of Freeze and Thaw Cycles of a Gas-Charged Heat Pipe

    Science.gov (United States)

    Ku, Jentung; Ottenstein, Laura; Krimchansky, Alexander

    2012-01-01

    The traditional constant conductance heat pipes (CCHPs) currently used on most spacecraft run the risk of bursting the pipe when the working fluid is frozen and later thawed. One method to avoid pipe bursting is to use a gas-charged heat pipe (GCHP) that can sustain repeated freeze/thaw cycles. The construction of the GCHP is similar to that of the traditional CCHP except that a small amount of non-condensable gas (NCG) is introduced and a small length is added to the CCHP condenser to serve as the NCG reservoir. During the normal operation, the NCG is mostly confined to the reservoir, and the GCHP functions as a passive variable conductance heat pipe (VCHP). When the liquid begins to freeze in the condenser section, the NCG will expand to fill the central core of the heat pipe, and ice will be formed only in the grooves located on the inner surface of the heat pipe in a controlled fashion. The ice will not bridge the diameter of the heat pipe, thus avoiding the risk of pipe bursting during freeze/thaw cycles. A GCHP using ammonia as the working fluid was fabricated and then tested inside a thermal vacuum chamber. The GCHP demonstrated a heat transport capability of more than 200W at 298K as designed. Twenty-seven freeze/thaw cycles were conducted under various conditions where the evaporator temperature ranged from 163K to 253K and the condenser/reservoir temperatures ranged from 123K to 173K. In all tests, the GCHP restarted without any problem with heat loads between 10W and 100W. No performance degradation was noticed after 27 freeze/thaw cycles. The ability of the GCHP to sustain repeated freeze/thaw cycles was thus successfully demonstrated.

  1. A vaccine cold chain freezing study in PNG highlights technology needs for hot climate countries.

    Science.gov (United States)

    Wirkas, Theo; Toikilik, Steven; Miller, Nan; Morgan, Chris; Clements, C John

    2007-01-08

    Fourteen data loggers were packed with vaccine vials at the national vaccine store, Port Moresby, Papua New Guinea (PNG), and sent to peripheral locations in the health system. The temperatures that the data loggers recorded during their passage along the cold chain indicated that heat damage was unlikely, but that all vials were exposed to freezing temperatures at some time. The commonest place where freezing conditions existed was during transport. The freezing conditions were likely induced by packing the vials too close to the ice packs that were themselves too cold, and with insufficient insulation between them. This situation was rectified and a repeat dispatch of data loggers demonstrated that the system had indeed been rectified. Avoiding freeze damage becomes even more important as the price of freeze-sensitive vaccines increases with the introduction of more multiple-antigen vaccines. This low-cost high-tech method of evaluating the cold chain function is highly recommended for developing and industrialized nations and should be used on a regular basis to check the integrity of the vaccine cold chain. The study highlights the need for technological solutions to avoid vaccine freezing, particularly in hot climate countries.

  2. Optimization of a pharmaceutical freeze-dried product and its process using an experimental design approach and innovative process analyzers.

    Science.gov (United States)

    De Beer, T R M; Wiggenhorn, M; Hawe, A; Kasper, J C; Almeida, A; Quinten, T; Friess, W; Winter, G; Vervaet, C; Remon, J P

    2011-02-15

    The aim of the present study was to examine the possibilities/advantages of using recently introduced in-line spectroscopic process analyzers (Raman, NIR and plasma emission spectroscopy), within well-designed experiments, for the optimization of a pharmaceutical formulation and its freeze-drying process. The formulation under investigation was a mannitol (crystalline bulking agent)-sucrose (lyo- and cryoprotector) excipient system. The effects of two formulation variables (mannitol/sucrose ratio and amount of NaCl) and three process variables (freezing rate, annealing temperature and secondary drying temperature) upon several critical process and product responses (onset and duration of ice crystallization, onset and duration of mannitol crystallization, duration of primary drying, residual moisture content and amount of mannitol hemi-hydrate in end product) were examined using a design of experiments (DOE) methodology. A 2-level fractional factorial design (2(5-1)=16 experiments+3 center points=19 experiments) was employed. All experiments were monitored in-line using Raman, NIR and plasma emission spectroscopy, which supply continuous process and product information during freeze-drying. Off-line X-ray powder diffraction analysis and Karl-Fisher titration were performed to determine the morphology and residual moisture content of the end product, respectively. In first instance, the results showed that - besides the previous described findings in De Beer et al., Anal. Chem. 81 (2009) 7639-7649 - Raman and NIR spectroscopy are able to monitor the product behavior throughout the complete annealing step during freeze-drying. The DOE approach allowed predicting the optimum combination of process and formulation parameters leading to the desired responses. Applying a mannitol/sucrose ratio of 4, without adding NaCl and processing the formulation without an annealing step, using a freezing rate of 0.9°C/min and a secondary drying temperature of 40°C resulted in

  3. Combination treatment of clostridium perfringens spores to freezing and/or gamma irradiation

    International Nuclear Information System (INIS)

    El-Fouly, M.Z.; El-Zawahry, Y.A.; Aziz, N.H.

    1985-01-01

    Freezing process alone caused relatively low decrease in viable count of suspended spores in minced meat while it decreased the spore numbers suspended in saline solution by more than one log cycle especially in case of the Egyptian strain. An abrupt decrease in viable counts of clostridium spores was observed by application dose of 1KGY either before or after freezing followed by gradual decrease of viable counts up to 15 KGY. The synergestic effect of combined treatment was clearly obvious for spores suspended in minced meat, which usually contains protective agents which increase the resistance of microorganisms against the separate treatment of radiation of freezing especially with spores of NCTC 8798 strain. Freezing the saline suspending medium before or after irradiation after the sensitivity of clostridium spores by only small extent and gave negative synergestic effect in some treatment. The percentages of injured spores due to the combined treatment were ranged between 15-100% of the viable counts. The percentage of injured spores tended to increase as the radiation dose levels increased

  4. Value of point-of-care ketones in assessing dehydration and acidosis in children with gastroenteritis.

    Science.gov (United States)

    Levy, Jason A; Waltzman, Mark; Monuteaux, Michael C; Bachur, Richard G

    2013-11-01

    Children with gastroenteritis often develop dehydration with metabolic acidosis. Serum ketones are frequently elevated in this population. The goal was to determine the relationship between initial serum ketone concentration and both the degree of dehydration and the magnitude of acidosis. This was a secondary analysis of a prospective trial of crystalloid administration for rapid rehydration. Children 6 months to 6 years of age with gastroenteritis and dehydration were enrolled. A point-of-care serum ketone (beta-hydroxybutyrate) concentration was obtained at the time of study enrollment. The relationship between initial serum ketone concentration and a prospectively assigned and previously validated clinical dehydration score, and serum bicarbonate concentration, was analyzed. A total of 188 patients were enrolled. The median serum ketone concentration was elevated at 3.1 mmol/L (interquartile range [IQR] = 1.2 to 4.6 mmol/L), and the median dehydration score was consistent with moderate dehydration. A significant positive relationship was found between serum ketone concentration and the clinical dehydration score (Spearman's rho = 0.22, p = 0.003). Patients with moderate dehydration had a higher median serum ketone concentration than those with mild dehydration (3.6 mmol/L vs. 1.4 mmol/L, p = 0.007). Additionally, the serum ketone concentration was inversely correlated with serum bicarbonate concentration (ρ = -0.26, p Children with gastroenteritis and dehydration have elevated serum ketone concentrations that correlate with both degree of dehydration and magnitude of metabolic acidosis. Point-of-care serum ketone measurement may be a useful tool to inform management decisions at the point of triage or in the initial evaluation of children with gastroenteritis and dehydration. © 2013 by the Society for Academic Emergency Medicine.

  5. Effect of freeze-thaw cycles on load transfer between the biomineral and collagen phases in bovine dentin

    Energy Technology Data Exchange (ETDEWEB)

    Deymier-Black, A.C., E-mail: AlixDeymier2010@u.northwestern.edu [Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208 (United States); Almer, J.D., E-mail: almer@aps.anl.gov [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Haeffner, D.R., E-mail: haeffner@aps.anl.gov [Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439 (United States); Dunand, D.C., E-mail: dunand@northwestern.edu [Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208 (United States)

    2011-10-10

    Stabilization of biological materials by freezing is widespread in the fields of medicine and biomaterials research and yet, in the case of hard biomaterials such as dentin, there is not a good understanding of how such treatments might affect the mechanical properties. The freezing and thawing may have a number of different effects on dentin including formation of cracks in the microstructure and denaturation of the collagen. Using high-energy synchrotron X-ray diffraction, the apparent moduli of bovine dentin samples were measured before and after various numbers of freeze-thaw cycles. It was determined that repeated freezing and thawing has no measurable effect on the hydroxyapatite or fibrillar apparent moduli up to 10 cycles. This confirms that the use of low temperature storage for stabilization of dentin is reasonable in cases where stiffness is a property of importance. Highlights: {yields} Studied the effect of freezing on the load transfer of HAP and fibrils in dentin. {yields} X-ray scattering measured HAP and fibril apparent moduli vs. freezing cycles. {yields} Apparent moduli did not vary significantly between 0 and 10 freeze thaw cycles. {yields} Residual strains imply no widespread cracking due to volumetric expansion of water. {yields} Dentin can be freeze-thawed with no significant effects on elastic properties.

  6. A Vivens Ex Vivo Study on the Synergistic Effect of Electrolysis and Freezing on the Cell Nucleus.

    Science.gov (United States)

    Lugnani, Franco; Zanconati, Fabrizio; Marcuzzo, Thomas; Bottin, Cristina; Mikus, Paul; Guenther, Enric; Klein, Nina; Rubinsky, Liel; Stehling, Michael K; Rubinsky, Boris

    2015-01-01

    Freezing-cryosurgery, and electrolysis-electrochemical therapy (EChT), are two important minimally invasive surgery tissue ablation technologies. Despite major advantages they also have some disadvantages. Cryosurgery cannot induce cell death at high subzero freezing temperatures and requires multiple freeze thaw cycles, while EChT requires high concentrations of electrolytic products-which makes it a lengthy procedure. Based on the observation that freezing increases the concentration of solutes (including products of electrolysis) in the frozen region and permeabilizes the cell membrane to these products, this study examines the hypothesis that there could be a synergistic effect between freezing and electrolysis in their use together for tissue ablation. Using an animal model we refer to as vivens ex vivo, which may be of value in reducing the use of animals for experiments, combined with a Hematoxylin stain of the nucleus, we show that there are clinically relevant protocols in which the cell nucleus appears intact when electrolysis and freezing are used separately but is affected by certain combinations of electrolysis and freezing.

  7. Monolayer freeze-fracture autoradiography: quantitative analysis of the transmembrane distribution of radioiodinated concanavalin A

    International Nuclear Information System (INIS)

    Fisher, K.A.

    1982-01-01

    The technique of monolayer freeze-fracture autoradiography (MONOFARG) has been developed and the principles, quantitation, and application of the method are described. Cell monolayers attached to polylysine-treated glass were freeze-fractured, shadowed, and coated with dry, Parlodion-supported Ilford L4 photographic emulsion at room temperature. Quantitative aspects of MONOFARG were examined using radioiodinated test systems. Background was routinely -4 grains/μm 2 /day, the highest overall efficiency was between 25% and 45%, and grain density and efficiency were dependent on radiation dose for iodine-125 and D-19 development. Corrected grain densities were linearly proportional to iodine-125 concentration. The method was applied to an examination of the transmembrane distribution of radioiodinated and fluoresceinated concanavalin A ( 125 I-FITC-Con-A). Human erythrocytes were labeled, column-purified, freeze-dried or freeze-fractured, autoradiographed, and examined by electron microscopy. The number of silver grains per square micrometer of unsplit single membrane was essentially identical to that of split extracellular membrane halves. These data demonstrate that 125 I-FITC-Con-A partitions exclusively with the extracellular half of the membrane upon freeze-fracturing and can be used as a quantitative marker for the fraction of extracellular split membrane halves. This method should be able to provide new information about certain transmembrane properties of biological membrane molecules and probes, as well as about the process of freeze-fracture per se

  8. Use of a soft sensor for the fast estimation of dried cake resistance during a freeze-drying cycle.

    Science.gov (United States)

    Bosca, Serena; Barresi, Antonello A; Fissore, Davide

    2013-07-15

    This paper deals with the determination of dried cake resistance in a freeze-drying process using the Smart Soft Sensor, a process analytical technology recently proposed by the authors to monitor the primary drying stage of a freeze-drying process. This sensor uses the measurement of product temperature, a mathematical model of the process, and the Kalman filter algorithm to estimate the residual amount of ice in the vial as a function of time, as well as the coefficient of heat transfer between the shelf and the product and the resistance of the dried cake to vapor flow. It does not require expensive (additional) hardware in a freeze-dryer, provided that thermocouples are available. At first, the effect of the insertion of the thermocouple in a vial on the structure of the product is investigated by means of experimental tests, comparing both sublimation rate and cake structure in vials with and without thermocouple. This is required to assess that the temperature measured by the thermocouple is the same of the product in the non-monitored vials, at least in a non-GMP environment, or when controlled nucleation methods are used. Then, results about cake resistance obtained in an extended experimental campaign with aqueous solutions containing different excipients (sucrose, mannitol and polyvinylpyrrolidone), processed in various operating conditions, are presented, with the goal to point out the accuracy of the proposed methodology. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. Near-Infrared Imaging for High-Throughput Screening of Moisture-Induced Changes in Freeze-Dried Formulations

    DEFF Research Database (Denmark)

    Trnka, Hjalte; Palou, Anna; Panouillot, Pierre Emanuel

    2014-01-01

    Evaluation of freeze-dried biopharmaceutical formulations requires careful analysis of multiple quality attributes. The aim of this study was to evaluate the use of near-infrared (NIR) imaging for fast analysis of water content and related physical properties in freeze-dried formulations. Model f...... tool for formulation development of freeze-dried samples. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci....

  10. Evaluating the freeze-thaw durability of portland cement-stabilized-solidified heavy metal waste using acoustic measurements

    International Nuclear Information System (INIS)

    El-Korchi, T.; Gress, D.; Baldwin, K.; Bishop, P.

    1989-01-01

    The use of stress wave propagation to assess freeze-thaw resistance of portland cement solidified/stabilized waste is presented. The stress wave technique is sensitive to the internal structure of the specimens and would detect structural deterioration independent of weight loss or visual observations. The freeze-thaw resistance of a cement-solidified cadmium waste and a control was evaluated. The control and cadmium wastes both showed poor freeze-thaw resistance. However, the addition of cadmium and seawater curing increased the resistance to more cycles of freezing and thawing. This is attributed to microstructural changes

  11. Ice nucleation activity in various tissues of Rhododendron flower buds: their relevance to extraorgan freezing

    Directory of Open Access Journals (Sweden)

    Masaya eIshikawa

    2015-03-01

    Full Text Available Wintering flower buds of cold hardy Rhododendron japonicum cooled slowly to subfreezing temperatures are known to undergo extraorgan freezing, whose mechanisms remain obscure. We revisited this material to demonstrate why bud scales freeze first in spite of their lower water content, why florets remain deeply supercooled and how seasonal adaptive responses occur in regard to extraorgan freezing in flower buds. We determined ice nucleation activity (INA of various flower bud tissues of using a test tube-based assay. Irrespective of collection sites, outer and inner bud scales that function as ice sinks in extraorgan freezing had high INA levels whilst florets that remain supercooled and act as a water source lacked INA. The INA level of bud scales was not high in late August when flower bud formation was ending, but increased to reach the highest level in late October just before the first autumnal freeze. The results support the following hypothesis: the high INA in bud scales functions as the subfreezing sensor, ensuring the primary freezing in bud scales at warmer subzero temperatures, which likely allows the migration of floret water to the bud scales and accumulation of icicles within the bud scales. The low INA in the florets helps them remain unfrozen by deep supercooling. The INA in the bud scales was resistant to grinding and autoclaving at 121°C for 15 min, implying the intrinsic nature of the INA rather than of microbial origin, whilst the INA in stem bark was autoclaving labile. Anti-nucleation activity (ANA was implicated in the leachate of autoclaved bud scales, which suppresses the INA at millimolar levels of concentration and likely differs from the colligative effects of the solutes. The tissue INA levels likely contribute to the establishment of freezing behaviors by ensuring the order of freezing in the tissues: from the primary freeze to the last tissue remaining unfrozen.

  12. 7 CFR 58.638 - Freezing the mix.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Freezing the mix. 58.638 Section 58.638 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) REGULATIONS AND STANDARDS UNDER THE...

  13. Gait-related cerebral alterations in patients with Parkinson's disease with freezing of gait

    NARCIS (Netherlands)

    Snijders, A.H.; Leunissen, H.P.; Bakker, M.; Overeem, S.; Helmich, R.C.G.; Bloem, B.R.; Toni, I.

    2011-01-01

    Freezing of gait is a common, debilitating feature of Parkinson’s disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between

  14. Gait-related cerebral alterations in patients with Parkinson's disease with freezing of gait

    NARCIS (Netherlands)

    Snijders, A.H.; Leunissen, I.; Bakker, M.; Overeem, S.; Helmich, R.C.G.; Bloem, B.R.; Toni, I.

    2011-01-01

    Freezing of gait is a common, debilitating feature of Parkinson's disease. We have studied gait planning in patients with freezing of gait, using motor imagery of walking in combination with functional magnetic resonance imaging. This approach exploits the large neural overlap that exists between

  15. Nitrate and dissolved organic carbon mobilization in response to soil freezing variability

    Science.gov (United States)

    Colin B. Fuss; Charles T. Driscoll; Peter M. Groffman; John L. Campbell; Lynn M. Christenson; Timothy J. Fahey; Melany C. Fisk; Myron J. Mitchell; Pamela H. Templer; Jorge Durán; Jennifer L. Morse

    2016-01-01

    Reduced snowpack and associated increases in soil freezing severity resulting from winter climate change have the potential to disrupt carbon (C) and nitrogen (N) cycling in soils. We used a natural winter climate gradient based on elevation and aspect in a northern hardwood forest to examine the effects of variability in soil freezing depth, duration, and frequency on...

  16. Preparation and Characterization of Solid Dispersions of Artemether by Freeze-Dried Method

    Directory of Open Access Journals (Sweden)

    Muhammad Tayyab Ansari

    2015-01-01

    Full Text Available Solid dispersions of artemether and polyethylene glycol 6000 (PEG6000 were prepared in ratio 12 : 88 (group-1. Self-emulsified solid dispersions of artemether were prepared by using polyethylene glycol 6000, Cremophor-A25, olive oil, Transcutol, and hydroxypropyl methylcellulose (HPMC in ratio 12 : 75 : 5 : 4 : 2 : 2, respectively (group-2. In third group, only Cremophor-A25 was replaced with Poloxamer 188 compared to group-2. The solid dispersions and self-emulsified solid dispersions were prepared by physical and freeze dried methods, respectively. All samples were characterized by X-ray diffraction, attenuated total reflectance Fourier transform infrared spectroscopy, differential scanning calorimeter, scanning electron microscopy, and solubility, dissolution, and stability studies. X-ray diffraction pattern revealed artemether complete crystalline, whereas physical mixture and freeze-dried mixture of all three groups showed reduced peak intensities. In attenuated total reflectance Fourier transform infrared spectroscopy spectra, C–H stretching vibrations of artemether were masked in all prepared samples, while C–H stretching vibrations were representative of polyethylene glycol 6000, Cremophor-A25, and Poloxamer 188. Differential scanning calorimetry showed decreased melting endotherm and increased enthalpy change (ΔH in both physical mixture and freeze-dried mixtures of all groups. Scanning electron microscopy of freeze-dried mixtures of all samples showed glassy appearance, size reduction, and embedment, while their physical mixture showed size reduction and embedment of artemether by excipients. In group-1, solubility was improved up to 15 times, whereas group-2 showed up to 121 times increase but, in group-3, when Poloxamer 188 was used instead of Cremophor-A25, solubility of freeze-dried mixtures was increased up to 135 times. In fasted state simulated gastric fluid at pH 1.6, the dissolution of physical

  17. Simulation of the process kinetics and analysis of physicochemical properties in the freeze drying of kale

    Science.gov (United States)

    Dziki, Dariusz; Polak, Renata; Rudy, Stanisław; Krzykowski, Andrzej; Gawlik-Dziki, Urszula; Różyło, Renata; Miś, Antoni; Combrzyński, Maciej

    2018-01-01

    Investigations were performed to study the freeze-drying process of kale (Brassica oleracea L. var acephala). The process of freeze-drying was performed at temperatures of 20, 40, and 60°C for whole pieces of leaves and for pulped leaves. The kinetics of the freeze-drying of both kale leaves and kale pulp were best described by the Page model. The increasing freeze-drying temperature from 20 to 60°C induced an approximately two-fold decrease in the drying time. Freeze-drying significantly increased the value of the lightness, delta Chroma, and browning index of kale, and had little influence on the hue angle. The highest increase in the lightness and delta Chroma was observed for whole leaves freeze-dried at 20°C. An increase in the drying temperature brought about a slight decrease in the lightness, delta Chroma and the total colour difference. Pulping decreased the lightness and hue angle, and increased browning index. Freeze-drying engendered a slight decrease in the total phenolics content and antioxidant activity, in comparison to fresh leaves. The temperature of the process and pulping had little influence on the total phenolics content and antioxidant activity of dried kale, but significantly decreased the contents of chlorophyll a and chlorophyll b.

  18. Dysfunctional freezing responses to approaching stimuli in persons with a looming cognitive style for physical threats

    Directory of Open Access Journals (Sweden)

    John H. Riskind

    2016-04-01

    Full Text Available Immobilizing freezing responses are associated with anxiety and may be etiologically related to several anxiety disorders. Although recent studies have sought to investigate the underlying mechanisms in freezing responses that are so problematic in many forms of anxiety, cognitive factors related to anxiety have not been investigated. This study was designed to investigate the potential moderating role of a well-documented cognitive vulnerability to anxiety, the Looming Cognitive Style (i.e., LCS; Riskind et al., 2000, which assesses the extent to which individuals tend to routinely interpret ambiguous threats (e.g., physical or social threats in a biased manner as approaching. We assessed participants’ Reaction Times (RTs when they made judgments about images of animals that differed in threat valence (threat or neutral and motion direction (approach or recede. As expected, LCS for concerns about the approach of physical dangers appeared to moderate freeze reactions. Individuals who were high on this LCS factor tended to generally exhibit a freeze-response (slower RTs and this was independent of the threat valence or motion direction of the animals. These general freezing reactions were in stark contrast to those of individuals who were low on the LCS factor for concerns about the approach of physical dangers. These participants tended to exhibit more selective and functional freezing responses that occurred only to threatening animals with approach motion; they did not exhibit freezing to neutral stimuli or any stimuli with receding motion. These findings did not appear to be explicable by a general slowing of RTs for the participants with high LCS. Moreover, the LCS factor for concerns about social threats (such as rejection or embarrassment was not related to differences in freezing; there was also no additional relationship of freezing to behavioral inhibition scores on the Behavioral Inhibition System and the Behavioral Activation System

  19. Synergistic structures from magnetic freeze casting with surface magnetized alumina particles and platelets.

    Science.gov (United States)

    Frank, Michael B; Hei Siu, Sze; Karandikar, Keyur; Liu, Chin-Hung; Naleway, Steven E; Porter, Michael M; Graeve, Olivia A; McKittrick, Joanna

    2017-12-01

    Magnetic freeze casting utilizes the freezing of water, a low magnetic field and surface magnetized materials to make multi-axis strengthened porous scaffolds. A much greater magnetic moment was measured for larger magnetized alumina platelets compared with smaller particles, which indicated that more platelet aggregation occurred within slurries. This led to more lamellar wall alignment along the magnetic field direction during magnetic freeze casting at 75 mT. Slurries with varying ratios of magnetized particles to platelets (0:1, 1:3, 1:1, 3:1, 7:1, 1:0) produced porous scaffolds with different structural features and degrees of lamellar wall alignment. The greatest mechanical enhancement in the magnetic field direction was identified in the synergistic condition with the highest particle to platelet ratio (7:1). Magnetic freeze casting with varying ratios of magnetized anisotropic and isotropic alumina provided insights about how heterogeneous morphologies aggregate within lamellar walls that impact mechanical properties. Fabrication of strengthened scaffolds with multi-axis aligned porosity was achieved without introducing different solid materials, freezing agents or additives. Resemblance of 7:1 particle to platelet scaffold microstructure to wood light-frame house construction is framed in the context of assembly inspiration being derived from both natural and synthetic sources. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Physical degradation of membrane electrode assemblies undergoing freeze/thaw cycling: Micro-structure effects

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S. [Fuel Cell Dynamics and Diagnostics Laboratory, Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Research and Development Division, Hyundai Motor Company, Yongin 446-912 (Korea); Mench, M.M. [Fuel Cell Dynamics and Diagnostics Laboratory, Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

    2007-11-22

    The objective of this work is to investigate physical damage of polymer electrolyte fuel cell (PEFC) materials subjected to freeze/thaw cycling. Effects of membrane electrode assembly micro-structures (catalyst layer cracking, membrane thickness, and membrane reinforcement) and diffusion media with micro-porous layers were analyzed by comparing scanning electron microscopy images of freeze/thaw cycled samples (-40 C/70 C) with those of virgin material and thermal cycled samples without freezing (5 C/70 C). Ex situ testing performed in this study has revealed a strong direction for the material choices in the PEFC and confirmed the previous computational model in the literature [S. He, M.M. Mench, J. Electrochem. Soc., 153 (2006) A1724-A1731; S. He, S.H. Kim, M.M. Mench, J. Electrochem. Soc., in press]. Specifically, the membrane electrode assemblies were found to be a source of water that can damage the catalyst layers under freeze/thaw conditions. Damage was found to occur almost exclusively under the channel, and not under the land (the graphite that touches the diffusion media). Conceptually, the best material to mitigate freeze-damage is a crack free virgin catalyst layer on a reinforced membrane that is as thin as possible, protected by a stiff diffusion media. (author)