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1

FREEZING POINT DEPRESSION OF VARIOUS ICE SLURRIES  

Microsoft Academic Search

Ideal solutions with equal molar concentration have an equal freezing point. The properties that determine heat and mass transfer processes encountered in a secondary cooling cycle are however determined by the mass fraction of solutes. Generally for aqueous solutions, the more freezing point depressant added, the less efficient heat and mass transfer properties. Therefore substances with low molecular weight are

J. W. Meewisse; C. A. Infante Ferreira

2

The Freezing Point Depression Law in Physical Chemistry.  

ERIC Educational Resources Information Center

Suggests a change in physical chemistry courses to use a slightly more complicated but significantly more useful generalization of the simple freezing point depression law. Lists reasons for the change and presents the treatment of solid-liquid equilibria where solid-solution is allowed. Provides a mathematical treatment. (MVL)

Franzen, Hugo F.

1988-01-01

3

Interpreting freezing point depression of stearic acid and methyl stearate  

Microsoft Academic Search

Freezing point depressions of binary systems including either stearic acid (SA) or methyl stearate (MES) were evaluated based on differential scanning calorimetry melting scans. The second binary component included a solvent from the group acetic acid, acetone, 2-butanone, and hexane. Vapor pressure as a function of liquid composition and temperature was used to measure vapor\\/liquid equilibrium. Activity coefficients were calculated

M. J. Goff; G. J. Suppes; M. A. Dasari

2005-01-01

4

Measurement of Freezing Point Depression of Selected Food Solutions  

NASA Astrophysics Data System (ADS)

Freezing point depression of selected food solutions were measured at various concentrations in order to reveal the characteristics of solid-liquid phase equilibrium. The measurement were carried out on a hand made apparatus that was calibrated before the measurement by some of selected reagents (acid and sugar) with known thermal properties. The results revealed that the freezing point depression of selected food solutions deviated from the behavior of the ideal solution with increasing solute concentration, so the water activity for non-ideal solution were introduced to the freezing point depression equation. Further, assuming that the heat of fusion was a equation of temperature, thus the following new equation was led, ln {(1-Xs)/(l-Xs+?·Xs + ?·Xs2)} = A(1/To - 1/Tf) - Bln(To/Tf) The goodness of fit of the equation showed the best results. Futhermore, by using the parameters a formula of freezing ratio and the relative water activities, which showed deviation from the ideal solution, were derived.

Murata, Satoshi; Tanaka, Fumihiko; Matsuoka, Takahisa

5

Measurement and data interpretation of the freezing point depression of milks  

Microsoft Academic Search

Freezing point depression of milks of various concentrations (i.e. 0–35 wt %) were measured by the thermistor cryoscope method. The method was initially validated using aqueous NaCl and sucrose solutions at high concentrations as their data are readily available in literature. The effect of fat content on freezing point depression of milk was found to be minimal. Effective molecular weights

Ping Chen; Xiao Dong Chen; Kevin W. Free

1996-01-01

6

Reappraisal of disparities between osmolality estimates by freezing point depression and vapor pressure deficit methods  

Microsoft Academic Search

As a response to recent expression of concern about possible unreliability of vapor pressure deficit measurements (K. Kiyosawa, Biophys. Chem. 104 (2003) 171–188), the results of published studies on the temperature dependence of the osmotic pressure of aqueous polyethylene glycol solutions are shown to account for the observed discrepancies between osmolality estimates obtained by freezing point depression and vapor pressure

Donald J. Winzor

2004-01-01

7

Performance Characteristics of a New Single-Sample Freezing Point Depression Osmometer  

Microsoft Academic Search

The Advanced® Model 3320 is an automated, single-sample freezing point depression (FPD) micro- osmometer that determines the total solute concentration (osmolality) of biological fluids, such as serum or urine. Osmolality measurements are commonly used by clinicians to assist in diagnosing and monitoring certain fluid and electrolyte imbalances in patients (i.e., hyponatremia, polyuria). FPD osmometers have been used in clinical chemistry

E. Garry; M. Pest; N. Zamp

2007-01-01

8

Ice slurry cooling research: Microscale study of ice particles characteristics, role of freezing point depressant, and influence on slurry fluidity  

Microsoft Academic Search

The influences of freezing-point-depressants on ice slurry characteristics in the form of ice slurry fluidity and on the microscale ice particle features are studied. The results identify microscale features of ice particles such as surface roughness that greatly influence slurry fluidity that are altered favorably by the use of a freezing point depressant. The engineering of a workable and efficient

K. Hayashi; K. Kasza

2000-01-01

9

Characterization of polymer networks by measurements of the freezing point depression  

Microsoft Academic Search

Based on the phenomenon of freezing point depression of a solvent by?T, experimental evidence is presented to show that the distance between the junction points can be calculated from?T. Direct measurements of the temperature-time-curve of the cooling network and the Differential Scanning Calorimetry offer the determination of?T. Except the mean distances ¯dc in dependence on cross-linking density, swelling degree, and

K. F. Arndt; P. Zander

1990-01-01

10

FREEZING POINT DEPRESSIONS IN SODIUM FLUORIDE. II. EFFECT OF TETRAVALENT FLUORIDES  

Microsoft Academic Search

The freezing point depressions in NaF caused by ZrFâ, HfFâ, ; ThFâ, and UFâ were measured and the excess partial molal free ; energies of solution of NaF calculated therefrom. All the deviations from ideal ; solution behavior were negative and greater than these for alkaline earth ; fluoride solutes. It was found that the deviations increase with the tetravalent

S. Cantor; T. S. Carlton

1962-01-01

11

Comparison of human tear film osmolarity measured by electrical impedance and freezing point depression techniques  

Microsoft Academic Search

Tear hyperosmolarity is diagnostic of dry eye disease (DED), yet difficulty in measurement has limited its utility; development of new instruments could facilitate its clinical application. This study compares the new OcuSense TearLab osmometer (OcuSense, Inc, San Diego, CA), based on electrical impedance “lab-on-a-chip” nanoliter technology, with the freezing point depression Clifton Osmometer (Clifton Technical Physics, Hartford, NY).

Alan Tomlinson; Louise C. McCann; Edward I Pearce

2010-01-01

12

Freezing point depression of water in phospholipid membranes: a solid-state NMR study.  

PubMed

Lipid-water interaction plays an important role in the properties of lipid bilayers, cryoprotectants, and membrane-associated peptides and proteins. The temperature at which water bound to lipid bilayers freezes is lower than that of free water. Here, we report a solid-state NMR investigation on the freezing point depression of water in phospholipid bilayers in the presence and absence of cholesterol. Deuterium NMR spectra at different temperatures ranging from -75 to + 10 degrees C were obtained from fully (2)H2O-hydrated POPC (1-palmitoyl-2-oleoylphosphatidylcholine) multilamellar vesicles (MLVs), prepared with and without cholesterol, to determine the freezing temperature of water and the effect of cholesterol on the freezing temperature of water in POPC bilayers. Our 2H NMR experiments reveal the motional behavior of unfrozen water molecules in POPC bilayers even at temperatures significantly below 0 degrees C and show that the presence of cholesterol further lowered the freezing temperature of water in POPC bilayers. These results suggest that in the presence of cholesterol the fluidity and dynamics of lipid bilayers can be retained even at very low temperatures as exist in the liquid crystalline phase of the lipid. Therefore, bilayer samples prepared with a cryoprotectant like cholesterol should enable the performance of multidimensional solid-state NMR experiments to investigate the structure, dynamics, and topology of membrane proteins at a very low temperature with enhanced sample stability and possibly a better sensitivity. Phosphorus-31 NMR data suggest that lipid bilayers can be aligned at low temperatures, while 15N NMR experiments demonstrate that such aligned samples can be used to enhance the signal-to-noise ratio of is 15N chemical shift spectra of a 37-residue human antimicrobial peptide, LL-37. PMID:18991419

Lee, Dong-Kuk; Kwon, Byung Soo; Ramamoorthy, Ayyalusamy

2008-12-01

13

Free Energy Perturbation Monte Carlo Simulations of Salt Influences on Aqueous Freezing Point Depression  

NASA Astrophysics Data System (ADS)

Free energy perturbation Monte Carlo (FEP/MC) simulations are performed for both the liquid and solid phases of water to determine the melting temperature of several popular three and four-site water models. Gibbs free energy vs. temperature plots are constructed from the simulations to determine the melting temperature. For the liquid phase, standard FEP/MC simulations are used to calculate the free energy relative to the gas phase at multiple temperatures. The free energy of the solid phase relative to the gas phase is calculated at multiple temperatures using the lattice-coupling method. The intersection of the free energy regression lines determines the estimate of the melting temperature. Additionally, simulations were carried out for simple salt solutions to determine the freezing point depressions (FPD). The simulations reproduce the FPD as a function of salt concentration for solutions of NaCl, KCl, CaCl2, and MgCl2.

Dick, Thomas J.; Wierzbicki, Andrzej; Madura, Jeffry D.

14

Relationship of amino acid composition and molecular weight of antifreeze glycopeptides to non-colligative freezing point depression.  

PubMed

Many polar fishes synthesize a group of eight glycopeptides that exhibit a non-colligative lowering of the freezing point of water. These glycopeptides range in molecular weight between 2600 and 33 700. The largest glycopeptides [1-5] lower the freezing point more than the small ones on a weight basis and contain only two amino acids, alanine and threonine, with the disaccharide galactose-N-acetyl-galactosamine attached to threonine. The small glycopeptides, 6, 7, and 8, also lower the freezing point and contain proline, which periodically substitutes for alanine. Glycopeptides with similar antifreeze properties isolated from the saffron cod and the Atlantic tomcod contain an additional amino acid, arginine, which substitutes for threonine in glycopeptide 6. In this study we address the question of whether differences in amino acid composition or molecular weight between large and small glycopeptides are responsible for the reduced freezing point depressing capability of the low molecular weight glycopeptides. The results indicate that the degree of amino acid substitutions that occur in glycopeptides 6-8 do not have a significant effect on the unusual freezing point lowering and that the observed decrease in freezing point depression with smaller glycopeptides can be accounted for on the basis of molecular weight. PMID:7115772

Schrag, J D; O'Grady, S M; DeVries, A L

1982-08-01

15

Relationship between swollen network structure of rubber vulcanizates and mechanism of freezing point depression of swelling solvent  

Microsoft Academic Search

In order to investigate the mechanism of freezing point depression (FPD) phenomena for polymer solutions and\\/or swollen rubber vulcanizates, some experiments related to this phenomenon have been carried out at a constant rate of cooling and at low temperatures. Thus far this phenomenon has not been explainable in terms of an ordinary colligative effect. In this study a new mechanism

H. Oikawa; K. Murakami

1989-01-01

16

Some spectroscopic and freezing point depression measurements on the homogeneous hydrogenation catalyst CoH 3 (PPh 3 ) 3  

Microsoft Academic Search

NMR, EPR and freezing point depression (FPD) experiments were performed on solutions of the homogeneous hydrogenation catalyst CoH3(PPh3)3. The results of these measurements show that the compound has a dynamic structure on the NMR time scale at room temperature and that it is slightly dissociated into bisphosphine species and free phosphine. FPD and1H-NMR measurements indicate that one Et2O molecule is

J. L. Hendrikse; J. W. E. Coenen; A. W. P. G. Peters Rit

1975-01-01

17

Crosslinking on ageing of elastomers II. Comparison of solvent freezing point depression and conventional crosslinking evaluation  

Microsoft Academic Search

The crosslinking of ethylene propylene diene monomer (EPDM) resulting from photooxidation was followed by DSC. The thermograms of solvent confined in the gel at equilibrium were recorded. A decrease of the freezing point of the solvent with the irradiation time was observed, together with a decrease of the heat of solidification of the solvent and a widening of the crystallization

Mohamed Baba; Jean-Luc Gardette; Jacques Lacoste

1999-01-01

18

Revised equation and table for determining the freezing point depression of H[sub 2]O-NaCl solutions  

SciTech Connect

Salinities of H[sub 2]O-salt inclusions are most often determined by measuring the melting temperature of ice in the inclusion and then referring this value to an equation or table describing the relationship between salinity and freezing-point depression. Generally, data for the system H[sub 2]O-NaCl are used to determine an NaCl-equivalent salinity, owing to lack of information concerning the salts (or other electrolytes) actually contributing to the freezing-point depression. The equation most often used to determine the salinity of H[sub 2]O-salt inclusions from freezing measurements is that of Potter et al (1978), which is based on a regression of data available in the literature at that time. More recently, Hall et al (1988) experimentally redetermined the ice-melting temperatures of H[sub 2]O-NaCl-KCl solutions having compositions ranging from pure water to the ternary eutectic and to each of the two binary (H[sub 2]O-NaCl and H[sub 2]O-KCl) eutectics.

Bodnar, R.J. (Virginia Polytechnic Inst. and State Univ., Blacksburg (United States))

1993-02-01

19

Saturation, Phase Composition and Freezing Point Depression in a Rigid Soil Model.  

National Technical Information Service (NTIS)

Calorimetry was used to explore the effects of saturation and temperature upon the phase composition of the water at below freezing temperatures in a porcelain block with fine pore spaces. The effect of pore size upon phase composition was held constant b...

G. R. Lange H. L. McKim

1967-01-01

20

Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico. [Freezing-point depression  

Microsoft Academic Search

A suite of samples composed primarily of halite from the upper Castile and lower Salado Formations of the Permian Basin was selected from Waste Isolation Pilot Plant (WIPP) core for a reconnaissance study of fluid inclusions. Volume percent of these trapped fluids averaged 0.7% to 1%. Freezing-point depressions varied widely and appeared to be unrelated to fluid-inclusion type, to sedimentary

2010-01-01

21

Preliminary report on fluid inclusions from halites in the Castile and lower Salado formations of the Delaware Basin, southeastern New Mexico. [Freezing-point depression  

SciTech Connect

A suite of samples composed primarily of halite from the upper Castile and lower Salado Formations of the Permian Basin was selected from Waste Isolation Pilot Plant (WIPP) core for a reconnaissance study of fluid inclusions. Volume percent of these trapped fluids averaged 0.7% to 1%. Freezing-point depressions varied widely and appeared to be unrelated to fluid-inclusion type, to sedimentary facies, or to stratigraphic depth. However, because very low freezing points were usually associated with anhydrite, a relation may exist between freezing-point data and lithology. Dissolved sulfate values were constant through the Castile, then decreased markedly with lesser depth in the lower Salado. This trend correlates very well with observed mineralogy and is consistent with an interpretation of the occurrence of secondary polyhalite as a result of gypsum or anhydrite alteration with simultaneous consumption of dissolved sulfate from the coexisting fluids. Together with the abundance and distribution of fluid inclusions in primary or ''hopper'' crystal structures, this evidence suggests that inclusions seen in these halites did not migrate any significant geographical distance since their formation. 28 refs., 17 figs., 2 tabs.

Stein, C.L.

1985-09-01

22

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

NASA Astrophysics Data System (ADS)

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.

Inaba, Hideo; Morita, Shin-Ichi

23

Freezing Point Depression within a Shear Field and the Effect of a Shear Field on Crystallization of Bi-Pb-Sn-Cd Alloy  

Microsoft Academic Search

A melting (or freezing) temperature, in general, is considered to be dependent only on pressure. However, in a recent paper a new idea was proposed, i.e. the temperature of a phase transition between a liquid and a solid is depressed when a shear field is applied to the materials. In this investigation an experimental study was made with a Bi-Pb-Sn-Cd

Hiroshi Mishina; Tadashi Sasada; Kunio Watanabe

1986-01-01

24

Solutions : FreezePtDepression (20 Variations)  

NSDL National Science Digital Library

It takes 6.86 kg of ethylene glycol (antifreeze) to decrease the freezing point of 6.50 kg of water to -25.0 o F (-31.7 o C). How much sodium chloride (NaCl) would it take to decrease the freezing point of 6.50 kg of water to -25.0 o F? (Assuming all the salt will dissolve in that amount of water.)

25

Plant Moisture Stress: A Portable Freezing-Point Meter Compared with the Psychrometer1  

Microsoft Academic Search

A small portable instrument for measuring the freezing- point depression of plant tissue has been developed for field use. The instrument is easy to operate and can be constructed from materials costing less than $100. Moisture stress measurements made with the Freezing- point meter on a variety of plants were compared with vapor pressure psychrometer measurments. Variation be- tween duplicates

J. W. Cary; H. D. Fisher

1969-01-01

26

Freezing Point of Milk: A Natural Way to Understand Colligative Properties  

ERIC Educational Resources Information Center

|A laboratory experiment is presented in which the freezing point depression is analyzed using milk as solution. The nature of milk as a mixture of different solutes makes it a suitable probe to learn about colligative properties. The first part of the experiment illustrates the analytical use of freezing point measurements to control milk…

Novo, Mercedes; Reija, Belen; Al-Soufi, Wajih

2007-01-01

27

Improve online freeze and cloud point control  

SciTech Connect

To improve financial performance, petroleum refiners want tighter control on individual processing units. Consequently, modern refineries are moving product-quality analytical functions closer to process. Historically, processing units sent product samples to the laboratory and made adjustments based on analytical results. In some cases, the lag time between sample procurement an data return could be several hours. During this time, the unit could be producing off-spec product or operating in a nonoptimized mode while waiting on lab results. Under these conditions, the cost to the refinery could mean the difference between a profit or loss. Many quality requirements are associated with the refined products. Some are regulatory mandates, others are market or seasonally driven and some are driven by yield and process optimization objectives. For example, freeze and cloud point are process control parameters that can increase yields and improve financial performance. Opting to use online analyzers to monitor/control freeze and cloud point specifications has potential economical advantages. The paper discusses freeze and cloud point data, common problems with analyzers, and two case histories of monitoring petroleum refinery streams.

Davidson, F.; Tsang, C. [Phase Technology, Richmond, British Columbia (Canada)

1997-01-01

28

Behavior of water below the freezing point in PEFCs  

Microsoft Academic Search

This study investigates the phenomenon of water freezing below the freezing point in polymer electrolyte fuel cell (PEFCs). Water generated on the surface of the catalyst layer was observed simultaneously with visible and infrared images. Surprisingly, it was found that water generated below the freezing point is in the liquid state and that the temperature rises to 0°C at the

Yuji Ishikawa; T. Morita; K. Nakata; K. Yoshida; M. Shiozawa

2007-01-01

29

Standard Reference Material 1744: Aluminum Freezing-Point Standard.  

National Technical Information Service (NTIS)

The freezing point of aluminum (660.323 deg. C) is a defining fixed point of the International Temperature Scale of 1990 (ITS-90). Realization of this freezing point is performed using a fixed-point cell containing high purity (greater than or equal to 99...

G. F. Strouse

1995-01-01

30

Do stratospheric aerosol droplets freeze above the ice frost point?  

Microsoft Academic Search

Laboratory experiments are presented which show that liquid stratospheric aerosol droplets under polar winter conditions do not freeze for temperatures higher than the water ice saturation temperature (frost point). Calorimetric measurements of the freezing of supercooled H2SO4\\/HNO3\\/H2O bulk solutions with concentrations typical of the polar stratospheric aerosol exhibit very small freezing rates, which exclude the possibility of homogeneous freezing of

T. Koop; U. M. Biermann; W. Raber; B. P. Luo; P. J. Crutzen; Th. Peter

1995-01-01

31

Some Factors Affecting the Freezing Point of Milk1  

Microsoft Academic Search

The freezing point of milk has served for over 30 years as an official method (2) for detecting adulteration of milk with added water. Current investigations (4, 7, 10) have indicated that the present standard of - 0.550 ° C. is too low for the average freezing point of milk, and that average values frequently fall be- tween -- 0.535

I. Sato; C. L. Hankinson; I. A. Gould; T. V. Armstrong

1957-01-01

32

FREEZING POINT DETERMINATIONS OF THE URANIUM HEXAFLUORIDE-HYDROGEN FLUORIDE SYSTEM  

Microsoft Academic Search

A more efficient and time-conserving method for the production analysis ; of small amounts of HF in UFâ is presented. The apparatus includes ; automatic controllingrecording equipment and thermistors. The amount of HF as an ; impurity is determined by measuring the depression in the UFâ freezing ; point. The use of calibration curves is necessary to correct for the

H. L. Bullard; A. S. Ostroski; W. S. Stringham

1957-01-01

33

THE URANIUM HEXAFLUORIDE-HYDROGEN FLUORIDE FREEZING POINT CURVE AND ITS APPLICATION TO A METHOD OF ANALYSIS  

Microsoft Academic Search

The freezing point curve for the system uranium hexafluoride--hydrogen ; fluoride was determined over the range 0.0 to 0.6 wt% hydrogen fluoride and is ; represented by the equation wt% HF = 0.0841 DELTA t + 0.1020 DELTA t² -- ; 0.1046 DELTA t³ + 0.0363 DELTA t⁴ where DELTA t is the depression ; of the freezing point of

R. J. Wertz; W. D. Hedge

1960-01-01

34

When the melting and freezing points are not the same  

NASA Astrophysics Data System (ADS)

Small clusters consisting of from four or five to 100 or 200 atoms or molecules can coexist as solids and liquids over a finite temperature range and have distinctly different melting and freezing points. It is argued that the study of clusters offers a bridge between reductionists and those researching the properties of large aggregates of atoms or molecules, since the unlinking of the freezing and melting points is readily detectable in a small system, but not in bulk matter. The concepts of potential well, free energy, and a quantum-mechanical interpretation of the allowed energies of clusters are reviewed and presented as theoretical bases for different freezing and melting points in clusters. Both laboratory experiments and computer simulations provide evidence to support this theory. In particular, computer-simulated time histories of mean temperatures of argon-13 clusters of various constant energies are presented which show the coexistence of liquid and solid clusters. It is concluded that, because clusters can exist in many different stable forms, future synthesis of new kinds of materials possessing certain desired microelectric, mechanical, or catalytic properties may be possible.

Berry, R. Stephen

1990-08-01

35

Freezing Points of Bulking Agents Used in Manufacture of Low-Calorie Frozen Desserts1  

Microsoft Academic Search

Freezing points of solutions of poly- dextrose, polydextrose partially neu- tralized with potassium hydroxide, sor- bitol, and microcrystalline cellulose at concentrations commonly used in frozen desserts were compared with those of similar concentrations of sucrose. Solu- tions of polydextrose and polydextrose partially neutralized with potassium hy- droxide exhibited higher freezing points. Freezing points of sorbitol solutions were lower and microcrystalline

Robert J. Baer; Kirk A. Baldwin

1984-01-01

36

Freezing and Melting  

NSDL National Science Digital Library

This article tells how the freezing point of a substance is also its melting point. The energy of the substance's molecules changes with temperature, thus with changes in state. Also described is how freezing points can be lowered, or depressed, by adding a substance.

2010-01-01

37

Standard Reference Materials: Tin Freezing-Point Standard: SRM 741a.  

National Technical Information Service (NTIS)

The freezing point of tin (231.928 degrees C) is a defining fixed point of the International Temperature Scale of 1990 (ITS-90). Realization of this freezing point is performed using a fixed-point cell containing high-purity (> or = 99.9999% pure) tin. A ...

G. F. Strouse N. P. Moiseeva

1999-01-01

38

Isotope effects in aqueous systems. VI. partial molal free energies in NaCl?H 2 O?D 2 O by freezing-point measurements. The heat of fusion of D 2 O  

Microsoft Academic Search

The freezing-point depressions of solutions of NaCl in normal and heavy water have been measured between 0.01 and 2m. Extrapolation of the isotope effect data to infinite dilution yields a new value for the heat of fusion of D2O at its melting point (?1507±3 cal-mole?1). The freezing-point data were employed to obtain osmotic coefficients at the feezing points of the

Quentin D. Craft; W. Alexander Hook

1975-01-01

39

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

40

Using undercooling to measure the freezing points of aqueous solutions  

Microsoft Academic Search

In this paper, a new type of sensor for in-line measurements of antifreeze mass fraction in aqueous solutions is described. Its principles of operation are based on the exploitation of the temperature rise that accompanies the freezing of an undercooled solution. Measurements are performed on small volume samples, taken from a distribution loop. The device operates in batch and is

Vincent Ayel; Olivier Lottin; Elena Popa; Hassan Peerhossaini

2005-01-01

41

Freezing Resistance in Some Antarctic Fishes  

Microsoft Academic Search

Measurements of serum freezing points in three Antarctic marine fishes indicated that they do not freeze in the -1.87 degrees C seawater because their blood is isosmotic to seawater. Concentrations of sodium chloride, urea, and free amino acids in the serum accounted for only half of the freezing-point depression of the serum. A protein containing carbohydrate was isolated which accounted

Arthur L. Devries; Donald E. Wohlschlag

1969-01-01

42

Simplified apparatus and procedure for freezing-point determinations upon small volumes of fluid  

Microsoft Academic Search

For purposes of determining the freezing-point of small volumes of aqueous solutions the difficulties of undercooling are avoided by first freezing the sample and then determining the thawing-point. Apparatus and procedure specially designed for simplicity of construction and operation are described. The method works best with volumes of the order of 10-3 to 10-4 mm3 and its accuracy in terms

J A Ramsay; R H J Brown

1955-01-01

43

Effects of impurities on the freezing plateau of the triple point of water  

NASA Astrophysics Data System (ADS)

The influence of impurities on the shape of the freezing curves of the triple point of water (TPW) in three small TPW cells was investigated using the freezing curve analysis method. We describe the procedure for preparing outer ice mantles in small TPW cells, for obtaining freezing plateaus, and for comparing the results between the old cell (s/n: 021) and the new cells (s/n: 001 and s/n: 008). The experimental results show that the maximum influence of impurities on the observed phase-transition temperature of water in the cell (s/n: 021) is approximately 0.2 mK below the peak temperature of the freezing plateau during freezing. Also, jagged temperature fluctuations were observed near the end of the freezing plateau in the old cell. However, these phenomena did not appear in the freezing plateaus of the new small cells. The equilibrium temperature realized with the old cell is 2.3 mK lower than that of the new cells, possibly due to excessive residual air. Therefore, assessing the effects of impurities on the TPW using an outer sheath method similar to that used in obtaining the fixed points of other metals is useful. Additionally, an estimated total mole fraction impurity concentration can be determined using Raoult's Law and the first cryoscopic constant for water.

Yan, X.; Zhang, J. T.; Duan, Y.; Wang, W.; Hao, X.

2013-09-01

44

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

NASA Astrophysics Data System (ADS)

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.

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

2008-06-01

45

Optimization of SPRT measurements of freezing in a zinc fixed-point cell  

NASA Astrophysics Data System (ADS)

A numerical model of solute and heat transport in extremely pure materials is described. Its purpose is to characterize the effect of impurities on the freezing curves of metals containing impurities at the level of less than 1 part per million. It is used to simulate experiments performed using a commercially available zinc fixed-point cell for SPRT calibrations. The aim is to determine the effect of different vertical temperature gradients on the freezing curve and to find out whether a range of conditions could be determined where there was a good fit between theory and experiment. For this fixed-point cell, agreement between the model and experiment improves as the distribution coefficient k ? 0. It is found that the model only agrees with the measured freezing curves over the entire freeze for a narrow range of furnace settings where the temperature profile is most uniform. We suggest that this is because if the furnace settings are not optimized, the solid does not grow uniformly, and freezing may continue in regions remote from the SPRT after the material in the vicinity of the SPRT has finished freezing, so distorting the freezing curve. This effect is not present in the model and so the method presented here enables optimization of the furnace to ensure the SPRT is surrounded by a liquid-solid interface over the entire freezing range. We find that the optimum thermal environment is extremely sensitive to the furnace settings; the optimum thermal environment is found when the temperature is slightly cooler at the top of the cell, as measured in the re-entrant well of the cell. We note that optimizing the freezing process is a necessary step towards using a thermal analysis to correct for the effects of impurities in the sample.

Pearce, J. V.; Veltcheva, R. I.; Lowe, D. H.; Malik, Z.; Hunt, J. D.

2012-06-01

46

When hot water freezes before cold  

Microsoft Academic Search

I suggest that the origin of the Mpemba effect (the freezing of hot water before cold) is due to freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. The solutes are concentrated ahead of the freezing front by zone refining in water that has not been

J. I. Katz

2009-01-01

47

Freeze-Thaw Processes and Soil Chemistry.  

National Technical Information Service (NTIS)

This review broadly examines the interactions between freeze-thaw processes and soil chemistry, focusing on (1) the effect of solutes on physical properties such as freezing-point depression, unfrozen water and frost heaving, (2) the effect of freeze-thaw...

G. M. Marion

1995-01-01

48

Measurement of the in freezing-point temperature: Effect of the liquid-solid interface structure  

NASA Astrophysics Data System (ADS)

The results of the experimental study of the inner interface formation process under different conditions of its initiation for the indium freezing point showed that, depending on the initiation intensity, both the planar structure of the interface on the thermometer well and a noticeable intergrowth of dendrites could be obtained. However, under some specific initiation conditions dendrites disappeared partly or completely in the process of crystallization. The value of the indium freezing point temperature was measured under realization conditions corresponding to different inner interface structure.

Ivanova, A. G.; Abasov, M. Yu.; Gerasimov, S. F.; Pokhodun, A. I.

2013-09-01

49

Thermodynamic temperature measurements of silver freezing point and HTFPs  

NASA Astrophysics Data System (ADS)

The hybrid method, by introducing a lens to the irradiance method, was adopted to measure the thermodynamic temperature at NIM. An absolute radiation thermometer was established with two alternative filter radiometers (633nm and 900nm). The parameters of the absolute radiation thermometer were calibrated. The thermodynamic temperatures of the silver fixed point and Co-C, Pt-C, Re-C were determined. The uncertainties were 0.24K to 0.94K for FR633 and 0.34K to 1.6K for FR900 from the silver point to Re-C. The results were compared with the ITS-90 values and show a good agreement: 0.18K at Co-C, -0.11K at Pt-C and -0.24K at Re-C, which are under the estimated uncertainties.

Yuan, Z.; Lu, X.; Hao, X.; Dong, W.; Wang, T.; Lin, Y.; Wang, J.; Duan, Y.

2013-09-01

50

Effects of Salt Concentration Changes During Freezing on the Unfrozen Water Content of Porous Materials  

Microsoft Academic Search

By combining equations for salt concentration by water removal from porous bodies with those for freezing point depression in normal solutions, equations are developed for calculating freezing point depression shifts due to the gradual removal of water upon freezing in porous bodies. The same equations can be used for the calculation of shifts in the osmotic potential of the water

Amos Banin; Duwayne M. Anderson

1974-01-01

51

Freezing point elevation in nanospace detected directly by atomic force microscopy  

Microsoft Academic Search

Following the earlier molecular simulation work by the authors, in which freezing point elevation in nanospace caused by the attractive potential energy from pore wall had been predicted, an experimental trial for finding the elevation phenomena was conducted, employing the so-called colloidal-probe Atomic Force Microscopy. A carbon microparticle was attached to the top of the cantilever tip, and its interaction

M. Miyahara; M. Sakamoto; H. Kanda; K. Higashitani

2002-01-01

52

Mechanism to Diminish the Supercooling of the Tin Freezing Point by using Graphite Powder  

NASA Astrophysics Data System (ADS)

The formation of crystallization centers from extremely pure molten tin is normally associated with deep supercooling. This deep supercooling is inconvenient for the operation of tin freezing-point cells, especially for sealed tin fixed-point cells without a holder to facilitate removal from the furnace. Researchers of the National Institute of Metrology (NIM) intended and succeeded in reducing this deep supercooling by adding fine and pure graphite powders to tin fixed-point cells without influencing the fixed-point temperature, but the mechanism is yet to be properly clarified. The principle of heterogeneous nucleation indicates that a decrease of the contact angle of the crystalline nucleus on the substrate surface results in a significant reduction of supercooling required for initiation of nucleation. The heterogeneous theory is utilized by the authors of this paper to give a reasonable description of the mechanism of supercooling reduction by addition of graphite powder. It is demonstrated that the freezing plateau can be realized by the natural cooling of the tin cell within the furnace without using the ‘outside nucleation’ technique. The maximum temperature of the freezing curves of the tin cell with graphite powder agrees well with the reference tin cell without the graphite powder, and the cells with graphite powder show good consistency.

Zhang, Jin Tao; Wang, Y. N.

2008-06-01

53

A method for on-line determination of residual water content and sublimation end-point during freeze-drying  

Microsoft Academic Search

Freeze-drying is a discontinuous process mainly used in the food and pharmaceutical industry to preserve the initial properties of raw products after dehydration. To date, the freeze-drying process has been monitored according to time-dependent empirical rules. Several authors have attempted to develop measuring systems for the on-line determination of the dehydration rate (freeze-drying kinetics) and the sublimation end-point. Of the

N. Genin; F. Rene; G. Corrieu

1996-01-01

54

Improvements in the realization of the ITS-90 over the temperature range from the melting point of gallium to the freezing point of silver at NIM  

NASA Astrophysics Data System (ADS)

The temperature primary standard over the range from the melting point of gallium to the freezing point of silver in National institute of Metrology (NIM), China, was established in the early 1990s. The performance of all of fixed-point furnaces degraded and needs to be updated due to many years of use. Nowadays, the satisfactory fixed point materials can be available with the development of the modern purification techniques. NIM plans to use a group of three cells for each defining fixed point temperature. In this way the eventual drift of individual cells can be evidenced by periodic intercomparison and this will increase the reliability in disseminating the ITS-90 in China. This article describes the recent improvements in realization of ITS-90 over temperature range from the melting point of gallium to the freezing point of silver at NIM. Taking advantages of the technological advances in the design and manufacture of furnaces, the new three-zone furnaces and the open-type fixed points were developed from the freezing point of indium to the freezing point of silver, and a furnace with the three-zone semiconductor cooling was designed to automatically realize the melting point of gallium. The reproducibility of the new melting point of gallium and the new open-type freezing points of In, Sn, Zn. Al and Ag is improved, especially the freezing points of Al and Ag with the reproducibility of 0.2mK and 0.5mK respectively. The expanded uncertainty in the realization of these defining fixed point temperatures is 0.34mK, 0.44mK, 0.54mK, 0.60mK, 1.30mK and 1.88mK respectively.

Sun, J.; Zhang, J. T.; Ping, Q.

2013-09-01

55

Ultra-high temperature isothermal furnace liners (IFLS) for copper freeze point cells  

NASA Astrophysics Data System (ADS)

Primary Laboratories use large fixed-point cells in deep calibration furnaces utilizing heat pipes to achieve temperature uniformity. This combination of furnace, heat pipe, and cell gives the smallest of uncertainties. The heat pipe, also known as an isothermal furnace liner (IFL), has typically been manufactured with Alloy 600/601 as the envelope material since the introduction of high temperature IFLs over 40 years ago. Alloy 600/601 is a widely available high temperature material, which is compatible with Cesium, Potassium, and Sodium and has adequate oxidation resistance and reasonable high temperature strength. Advanced Cooling Technologies, Inc. (ACT) Alloy 600/Sodium IFLs are rated to 1100°C for approximately 1000 hours of operation (based on creep strength). Laboratories interested in performing calibrations and studies around the copper freezing point (1084.62°C) were frustrated by the 1000 hours at 1100°C limitation and the fact that expensive freeze-point cells were getting stuck and/or crushed inside the IFL. Because of this growing frustration/need, ACT developed an Ultra High Temperature IFL to take advantage of the exceptional high temperature strength properties of Haynes 230.

Dussinger, P. M.; Tavener, J. P.

2013-09-01

56

Computational fluid dynamics simulations of jet fuel flow near the freeze point temperature  

NASA Astrophysics Data System (ADS)

Under low-temperature environmental conditions, the cooling of aircraft fuel results in reduced fluidity with the potential for freezing. Therefore, it is important to study the flow and heat transfer phenomena that occur in an aircraft fuel tank near the freeze point temperature of jet fuels. The purpose of this dissertation is to study the effects of low temperatures on the flow, heat transfer and freezing of commercial and military jet fuels. The research is accomplished with the help of computational models of a thermal simulator tank and a quartz duct. Experimental results with the thermal simulator tank show that fuel flowability and pumpability decrease substantially as temperature is reduced. Time-dependent temperature and velocity distributions were numerically simulated for static cooling. Measured properties were used in all the computational fluid dynamics simulations. The calculations show that stringers, ribs, and other structures strongly promote fuel cooling. Also, the cooler, denser fuel resides near the bottom surface of the fuel tank simulator. The presence of an ullage space within the tank was found to strongly influence the fuel temperature profile by sometimes reducing cooling from the upper surface. Moreover, since the presence of ullage space is an explosion risk, some military aircraft fuel tanks are fitted with explosion suppressant polyurethane foam. To study the effect of foam on the flowability and heat transfer inside the simulator tank, the wing tank thermal simulator was filled with military specified polyurethane foam. The tank was simultaneously drained and cooled and the mass flow rate results showed that flowability of the fuel is not affected by the presence of foam. However, the presence of foam certainly affected the heat transfer phenomenon inside the fuel tank when the simulator tank was cooled and drained simultaneously. To study the freezing behavior of jet fuel under forced flow conditions, a quartz duct was fabricated. The duct walls were cooled below the solidification temperatures of JP-8 and JPTS fuel samples. Freezing was also simulated using computational fluid dynamics, and the validity of the calculations was established by comparing them with experimental measurements. This work demonstrates that computational fluid dynamics techniques can potentially be used to predict fuel hold-up in aircraft fuel tanks. The effect of flow rate on solidification was also simulated, and it was found that lower flow rates result in relatively more solidification of the fuel than do higher flow rates. The simulations of the freezing behaviors of JP-8 and JPTS samples were found to have essentially the same value of morphology constant. However, the crystal structures of these two fuels were studied in experiments and were found to be very different. This shows the inability of the model to capture small-scale details like the crystal microstructure. However, this limitation is not fatal here because the focus is on the overall flow and freezing behavior of jet fuels. The model was successful in predicting the freezing behavior by comparing the calculated frozen area obtained by the model with the measured area.

Assudani, Rajee

57

Influence of the Freezing and Annealing Conditions on the Realization of Cryogenic Triple Points  

NASA Astrophysics Data System (ADS)

As a basis for evaluating the results of an international star comparison of sealed fixed-point cells, dedicated investigations have been directed to the dependence of the melting temperature on different conditions concerning the preparation of the solid phase, i.e., fast and slow freezing, refreezing without supercooling, or annealing at a temperature of only a few mK below the melting temperature. Differences in the typical thermophysical behavior of the four fixed-point substances hydrogen, neon, oxygen, and argon have been found. In the case of hydrogen and oxygen, the quality of the crystal lattice has little influence on the melting temperature. This enables temperature widths of the melting curves of only a few tens of ?K, if there are no additional influences. On the contrary, argon samples frozen after supercooling with different velocities of freezing typically melt within a range of 0.3 mK. The melting-curve width can be reduced only by refreezing. A broader melting range of a few tenths of mK has been typically observed for neon cells. Unlike argon, an improvement of the crystal quality by a slow refreezing does not decrease the width of the melting-curve.

Wolber, L.; Fellmuth, B.

2008-02-01

58

Study on the melting and freezing behaviour of high temperature binary eutectic fixed points using differential scanning calorimetry  

NASA Astrophysics Data System (ADS)

We have measured the heat flux accompanying the melting or freezing of metal (or metalloid)-carbon eutectics, using differential scanning calorimetry (DSC) to identify appropriate binary systems for secondary thermometry fixed points. Well-known alloy systems such as Fe-C and Ni-C showed reproducible endothermic and exothermic peaks that represent melting and freezing reactions in the DSC measurement. Furthermore, a new Si-C system with a eutectic composition showed reproducible melting and freezing peaks in the DSC measurements. Based on the results by DSC, we identified the Si-SiC eutectic point as a possible eutectic fixed point. To confirm this possibility, we made a Si-SiC cell for thermocouple thermometry and measured its melting and freezing characteristics using a Pt/Pd thermocouple. The melting temperature of the Si-SiC eutectic was reproducible to within 0.02 °C (one standard deviation). From the results, we found that Si-SiC has possibility as a new eutectic fixed point at temperatures around 1400 °C. We also concluded that DSC analysis could be used to measure the reproducibility of freezing and melting reactions that are to be used as fixed points for thermometry, because it is a rapid and easy-to-use tool for characterizing the thermal behaviour of materials with only a small sample.

Kwon, Su Yong; Kim, Yong-Gyoo; Yang, Inseok

2010-06-01

59

The initial freezing point temperature of beef rises with the rise in pH: a short communication.  

PubMed

This study tested the hypothesis that the initial freezing point temperature of meat is affected by pH. Sixty four bovine M. longissimus thoracis et lumborum were classified into two ultimate pH groups: low (<5.8) and high pH (>6.2) and their cooling and freezing point temperatures were determined. The initial freezing temperatures for beef ranged from -0.9 to -1.5°C (?=0.6°C) with the higher and lower temperatures associated with high and low ultimate pH respectively. There was a significant correlation (r=+0.73, P<0.01) between beef pH and freezing point temperature in the present study. The outcome of this study has implications for the meat industry where evidence of freezing (ice formation) in a shipment as a result of high pH meat could result in a container load of valuable chilled product being downgraded to a lower value frozen product. PMID:23410892

Farouk, M M; Kemp, R M; Cartwright, S; North, M

2013-01-11

60

Freezing induces a loss of freeze tolerance in an overwintering insect.  

PubMed Central

Cold-hardy insects overwinter by one of two main strategies: freeze tolerance and freeze avoidance by supercooling. As a general model, many freeze-tolerant species overwinter in extreme climates, freeze above -10 degrees C via induction by ice-nucleating agents, and once frozen, can survive at temperatures of up to 40 degrees C or more below the initial freezing temperature or supercooling point (SCP). It has been assumed that the SCP of freeze-tolerant insects is unaffected by the freezing process and that the freeze-tolerant state is therefore retained in winter though successive freeze-thaw cycles of the body tissues and fluids. Studies on the freeze-tolerant larva of the hoverfly Syrphus ribesii reveal this assumption to be untrue. When a sample with a mean 'first freeze' SCP of -7.6 degrees C (range of -5 degrees C to -9.5 degrees C) were cooled, either to -10 degrees C or to their individual SCP, on five occasions, the mean SCP was significantly depressed, with some larvae subsequently freezing as low as -28 degrees C. Only larvae that froze at the same consistently high temperature above -10 degrees C were alive after being frozen five times. The wider occurrence of this phenomenon would require a fundamental reassessment of the dynamics and distinctions of the freeze-tolerant and freeze-avoiding strategies of insect overwintering.

Brown, C L; Bale, J S; Walters, K F A

2004-01-01

61

A psychometric cut-point to separate emergently suicidal depressed patients from stable depressed outpatients  

PubMed Central

Context: The design of safe clinical trials targeting suicidal ideation requires operational definitions of what degree of suicidal ideation is too excessive to allow safe participation. Aims: We examined the Scale for Suicide Ideation (SSI) to develop a psychometric cut-point that would identify patients having a suicidal emergency. Settings and Design: The Emergency Department (ED) and the out-patient clinic of a university hospital. Materials and Methods: We used the SSI to contrast 23 stable, depressed adult out-patients versus 11 depressed adult ED patients awaiting psychiatric admission for a suicidal emergency. Statistical Analysis: The performance of the SSI was examined with nominal logistic regression. Results: ED patients were older than out-patients (P<0.001), with proportionally more men (P<0.05), and were more ethnically diverse than the outpatients (P<0.005). Compared to out-patients, ED patients were more depressed (Patient Health Questionnaire-9 score 23.1±3.8 vs. 11.7±7.3, P<0.005) and reported a greater degree of suicidal ideation (SSI scores 25.7±7.3 vs. 4.2±8.4, P<0.0001). Nominal logistic regression for the univariate model of SSI score and group yielded a score of 16 (P<0.0001) as the best cut-point in separating groups, with a corresponding Receiver Operating Characteristic Area Under the Curve = 0.94. Of 34 patients in the total sample, only two were misclassified by SSI score = 16, with both of these being false positive for ED status. Thus, the sensitivity of the cut-point was 100% with specificity of 91%. When the model was expanded to include SSI along with age, gender, ethnicity, sedative-hypnotic use, and over-the-counter use, only SSI score remained significant as a predictor. Conclusions: A SSI score ?16 may be useful as an exclusion criterion for out-patients in depression clinical trials.

McCall, W. Vaughn; Batson, Nicolas; Webster, Megan; Joshi, Indu; Derreberry, Todd; McDonough, Adam; Farris, Suzan

2013-01-01

62

Osmotic coefficient of aqueous solutions of cyclohexylsulfamic Acid at the freezing point of solutions.  

PubMed

The osmotic coefficient of aqueous solutions of cyclohexylsulfamic acid was determined by freezing point measurements up to the molality 0.65 mol kg-1. The osmotic coefficients were fitted to the Pitzer equation, and ion interaction parameters ?1, ?(0) and ?(1) were evaluated. The mean ion activity coefficient of the solute was calculated, and the non-ideal behaviour of the system investigated was characterized by calculation of the excess Gibbs energy of solution, as well as the respective partial molar functions of solute and solvent. The partial molar excess Gibbs energy of the solute is negative, like the excess Gibbs energy of its solution, while the partial molar excess Gibbs energy of the solvent is positive and increases with increasing concentration of the solute. The solvation ability of water was calculated from the difference between the Gibbs energy of solution of water in solution and that of pure water, and found to be positive and small for the solute investigated, throughout the concentration range studied. PMID:24061887

Bešter-Roga?, Marija; Klofutar, Cveto; Rudan-Tasi?, Darja

2010-12-01

63

TOPICAL REVIEW: Confinement effects on freezing and melting  

Microsoft Academic Search

A review of experimental work on freezing and melting in confinement is presented. A range of systems, from metal oxide gels to porous glasses to novel nanoporous materials, is discussed. Features such as melting-point depression, hysteresis between freezing and melting, modifications to bulk solid structure and solid-solid transitions are reviewed for substances such as helium, organic fluids, water and metals.

Hugo K. Christenson

2001-01-01

64

Freezing points of H2SO4 aqueous solutions and formation of stratospheric ice clouds  

Microsoft Academic Search

The freezing temperature of H2SO4 aqueous solutions as a function of concentration was experimentally measured in an investigation of the ice nucleation of natural H2SO4 mixed aerosols. Based on these measurements, it is suggested that the formation of ice crystals in cirrus and polar stratospheric clouds is the result of the condensation of water vapor and subsequent freezing of natural

Takeshi Ohtake

1993-01-01

65

Planar solidification of a finite slab: effects of the pressure dependence of the freezing point  

Microsoft Academic Search

Planar solidification in a slab of finite thickness is numerically simulated. The solid density is assumed to be lower than the liquid density and the phase change material expands while freezing (e.g. water). The effects of an opposing elastic force, due to the interaction with the container, are analysed. The increasing pressure determines a continuous lowering of the melting temperature;

M. Conti

1995-01-01

66

Molecular Dynamics Study of Freezing Point and Solid-Liquid Interfacial Free Energy of Stockmayer Fluids  

SciTech Connect

Freezing temperatures of Stockmayer fluids with different dipolar strength at zero pressure are estimated and computed using three independent molecular-dynamics (MD) simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature (NPT) two phase coexistence method, and the constant-pressure and constant-enthalpy (NPH) coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with a reduced dipole moment is 0.656 0.001, 0.726 0.002 and 0.835 0.005, respectively. The freezing temperature increases with the dipolar strength. The solid-liquid interfacial free energies of the (111), (110) and (100) interface are calculated for the first time using two independent methods, namely, the cleaving-wall method and the interfacial fluctuation method. Both methods predict that the interfacial free energy increases with the dipole moment. Although the interfacial fluctuation method suggests a weaker interfacial anisotropy, particularly for strongly dipolar SM fluids, both methods predicted the same trend of interfacial anisotropy, that is, .

Wang, J. [University of Nebraska, Lincoln; Apte, Pankaj [Indian Institute of Technology, Kanpur; Morris, James R [ORNL; Zeng, X.C. [University of Nebraska, Lincoln

2013-01-01

67

Freezing points and small-scale deicing tests for salts of levulinic acid made from grain sorghum.  

PubMed

Deicers from renewable resources are needed to overcome the disadvantages of using traditional deicers. Salts made from levulinic acid produced using grain sorghum as raw material were tested as road deicing agents. Freezing points of these salts viz., sodium levulinate, magnesium levulinate and calcium levulinate along with rock salt (sodium chloride) were determined according to American Society for Testing and Materials (ASTM) D 1177-94 standard at concentrations of 10, 20, 30 and 40 % w/w. There were significant differences among the freezing points of the salts. Freezing points for rock salt, sodium levulinate, calcium levulinate and magnesium levulinate, for different concentrations, were in the ranges of -6.6 to -20.5, -2.9 to -15.0, -2.1 to -7.8 and -1.5 to -6.5 degrees C, respectively. Deicing effectiveness of the salts of levulinic acid were investigated by conducting small-scale deicing tests with aqueous solutions of various salt concentrations (2%, 5% and 10%) in a laboratory freezer and by spraying the deicer on a graveled surface covered by ice and snow with the average temperature during the testing at -2.7 degrees C. Deicing capabilities of the three salts of levulinic acid differed. At -2.7 degrees C, all three salts caused melting of the ice. Among the different levulinates studied sodium levulinate was the most effective deicing agent. These salts of levulinates could be a viable replacement for traditional deicers and could help in reducing the disadvantages of traditional deicers. PMID:17416518

Ganjyal, G; Fang, Q; Hanna, M A

2007-04-09

68

A comment on the Equation of State and the freezing point equation with respect to subglacial lake modelling  

NASA Astrophysics Data System (ADS)

The empirical Equation of State (EOS) allows the calculation of the density of water in dependence of salinity, temperature, and pressure. Water density is an important quantity to determine the internal structure and flow regime of ocean and lakes. Hence, its exact representation in numerical models is of utmost importance for the specific simulation results. The three parameters namely salinity, temperature, and pressure have a complex interdependency on the EOS. Whether warmer water parcels sink or rise, therefore depends on the surrounding salinity and pressure. The empirical Equation of Freezing Point (EOFP) allows to calculate the pressure- and salinity-dependent freezing point of water. Both equations are necessary to model the basal mass balance below Antarctic ice shelves or at the ice-water interface of subglacial lakes. This article aims three tasks: first we comment on the most common formulations of the EOS and the EOFP applied in numerical ocean and lake models during the past decades. Then we describe the impact of the recent and self-consistent Gibbs thermodynamic potential formulation of the EOS and the EOFP on subglacial lake modelling. Finally, we show that the circulation regime of subglacial lakes covered by at least 3000 m of ice, in principle, is independent of the particular formulation, in contrast to lakes covered by a shallower ice sheet, like e.g., Subglacial Lake Ellsworth. However, as modelled values like the freezing and melting patterns or the distribution of accreted ice at the ice-lake interface are sensitive to different EOS and EOFP, we present updated values for Subglacial Lake Vostok and Subglacial Lake Concordia.

Thoma, Malte; Grosfeld, Klaus; Smith, Andrew M.; Mayer, Christoph

2010-05-01

69

Pour-point depression of crude oils by addition of tar sand bitumen  

SciTech Connect

A process is described for reducing the pour point of a crude oil which comprises adding a pour-point depressant selected from the group consisting of a raw tar sands bitumen and hydrotreated tar sands bitumen to form a blend possessing a relatively lower pour point.

Soderberg, D.J.

1988-03-01

70

Freezing-point depressing peptides and glycoproteins from Arctic-boreal and Antarctic fish  

Microsoft Academic Search

Antifreeze glycoproteins have been isolated from the Antarctic Nototheniid Trematomus hansoni and the Chaenichthyid species Chionodraco hamatus and Chaenocephalus aceratus. Their molecular weights range from 7,400–62,000 Daltons. The amino acid and sugar composition of these glycoproteins indicate that they consist of the same subunits which are known from related Nototheniids. In the Arctic-boreal sculpin Myoxocephalus scorpius two antifreeze peptides with

R. Schneppenheim; H. Theede

1982-01-01

71

Experimental and Analytical Investigation of a Freezing Point Depressant Fluid Ice Protection System.  

National Technical Information Service (NTIS)

A glycol-exuding porous leading edge ice protection system was tested in the NASA Icing Research Tunnel. Stainless steel mesh, laser drilled titanium, and composite panels were tested on two general aviation wing sections. Two different glycol-water solut...

A. E. Albright

1984-01-01

72

The Siberian timberman Acanthocinus aedilis : a freeze-tolerant beetle with low supercooling points  

Microsoft Academic Search

Larvae of the Siberian timberman beetle Acanthocinus aedilis display a number of unique features, which may have important implications for the field of cold hardiness in general. Their\\u000a supercooling points are scattered over a wide temperature range, and some individuals have supercooling points in the low\\u000a range of other longhorn beetles. However, they differ from other longhorn beetles in being

E. Kristiansen; N. G. Li; A. I. Averensky; A. E. Laugsand; K. E. Zachariassen

2009-01-01

73

Effect of Thawing Time, Cooling Rate and Boron Nutrition on Freezing Point of the Primordial Shoot in Norway Spruce Buds  

PubMed Central

• Background Effects of cooling rates on bud frost hardiness have been studied but there is little information on bud responses to thawing. Since the cell wall pore size has been found to increase with boron (B) deficiency, B deficiency may affect the supercooling ability of buds in winter. • Methods The effects of duration of thawing time and rate of cooling on bud frost hardiness of Norway spruce (Picea abies) were studied in a B fertilization trial in February 2003 and March 2005. Frost hardiness of apical buds was determined by differential thermal analysis (DTA) and visual scoring of damage. • Key Results In 2003, the freezing point of primordial shoots of buds (Tf), i.e. the low-temperature exotherm (LTE), was, on average, ?39?°C when buds were thawed for less than 3?h and the Tf increased to ?21?°C after 18?h of thawing. During the first 4?h of thawing, the rate of dehardening was 6?°C h?1. In 2005, buds dehardened linearly from ?39?°C to ?35?°C at a rate of 0·7?°C h?1. In 2003, different cooling rates of 1–5?°C h?1 had a minor effect on Tf but in 2005 with slow cooling rates Tf decreased. In both samplings, at cooling rates of 2 and 1?°C h?1, Tf was slightly higher in B-fertilized than in non-fertilized trees. By contrast, at very short thawing times in 2003, Tf was somewhat lower in B-fertilized trees. • Conclusions There was little evidence of reduced frost hardiness in trees with low B status. This study showed that buds deharden rapidly when exposed to above-freezing temperatures in winter, but if cooled again they reharden more slowly. According to this study, rapid dehardening of buds has to be taken into account in assessments of frost hardiness.

RAISANEN, MIKKO; REPO, TAPANI; LEHTO, TARJA

2006-01-01

74

Detecting critical decision points in psychotherapy and psychotherapy + medication for chronic depression.  

PubMed

Objective: We sought to quantify clinical decision points for identifying depression treatment nonremitters prior to end-of-treatment. Method: Data came from the psychotherapy arms of a randomized clinical trial for chronic depression. Participants (n = 352; 65.6% female; 92.3% White; mean age = 44.3 years) received 12 weeks of cognitive behavioral analysis system of psychotherapy (CBASP) or CBASP plus an antidepressant medication. In half of the sample, receiver operating curve analyses were used to identify efficient percentage of symptom reduction cut points on the Inventory of Depressive Symptoms-Self-Report (IDS-SR) for predicting end-of-treatment nonremission based on the Hamilton Rating Scale for Depression (HRSD). Sensitivity, specificity, predictive values, and Cohen's kappa for identified cut points were calculated using the remaining half of the sample. Results: Percentage of IDS-SR symptom reduction at Weeks 6 and 8 predicted end-of-treatment HRSD remission status in both the combined treatment (Week 6 cut point = 50.0%, Cohen's ? = .42; Week 8 cut point = 54.3%, Cohen's ? = .45) and psychotherapy only (Week 6 cut point = 60.7%, Cohen's ? = .41; Week 8 cut point = 48.7%, Cohen's ? = .49). Status at Week 8 was more reliable for identifying nonremitters in psychotherapy-only treatment. Conclusions: Those with chronic depression who will not remit in structured, time-limited psychotherapy for depression, either with therapy alone or in combination with antidepressant medication, are identifiable prior to end of treatment. Findings provide an operationalized strategy for designing adaptive psychotherapy interventions. (PsycINFO Database Record (c) 2013 APA, all rights reserved). PMID:23750462

Steidtmann, Dana; Manber, Rachel; Blasey, Christine; Markowitz, John C; Klein, Daniel N; Rothbaum, Barbara O; Thase, Michael E; Kocsis, James H; Arnow, Bruce A

2013-06-10

75

UME Radiation Thermometer Calibration Facilities below the Freezing Point of Silver (961.78 °C)  

NASA Astrophysics Data System (ADS)

Facilities at UME for the calibration of radiation thermometers are described for temperatures generally below 961.78 °C, the lower limit of temperature defined by radiation thermometry on the International Temperature Scale of 1990 (ITS-90). Traceability in the range 200 °C to 1100 °C is obtained using fixed-point blackbody radiators, while traceability from -30 °C to 200 °C is obtained through a homemade variable-temperature blackbody with calibrated 100 ? Pt (Pt100) temperature sensors. The best overall uncertainty for the first range is 0.6 °C, and 0.3 °C for the second range (k=2).

Diril, Ahmet; Nasibov, Humbat; U?ur, Sevilay

2003-09-01

76

Size-dependent melting point depression of nanostructures: Nanocalorimetric measurements  

Microsoft Academic Search

The melting behavior of 0.1-10-nm-thick discontinuous indium films formed by evaporation on amorphous silicon nitride is investigated by an ultrasensitive thin-film scanning calorimetry technique. The films consist of ensembles of nanostructures for which the size dependence of the melting temperature and latent heat of fusion are determined. The relationship between the nanostructure radius and the corresponding melting point and latent

M. Zhang; M. Yu. Efremov; F. Schiettekatte; E. A. Olson; A. T. Kwan; S. L. Lai; T. Wisleder; J. E. Greene; L. H. Allen

2000-01-01

77

Activity coefficients and free energies of nonionic mixed surfactant solutions from vapor-pressure and freezing-point osmometry.  

PubMed

The thermodynamic properties of mixed surfactant solutions are widely investigated, prompted by numerous practical applications of these systems and by interest in molecular association and self-organization. General techniques for measuring thermodynamic activities, such as isopiestic equilibration, are well-established for multicomponent solutions. Surprisingly, these techniques have not yet been applied to mixed surfactant solutions, despite the importance of the free energy for micelle stability. In this study, equations are developed for the osmotic coefficients of solutions of nonionic surfactant A + nonionic surfactant B. A mass-action model is used, with virial equations for the activity coefficients of the micelles and free surfactant monomer species. The equations are fitted to osmotic coefficients of aqueous decylsulfobetaine + dodecylsulfobetaine solutions measured by vapor-pressure and freezing-point osmometry. Equilibrium constants for mixed-micelle formation are calculated from the free monomer concentrations at the critical micelle concentrations. The derived activity coefficients of the micelles and free monomers indicate large departures from ideal solution behavior, even for dilute solutions of the surfactants. Stoichiometric activity coefficients of the total surfactant components are evaluated by Gibbs-Duhem integration of the osmotic coefficients. Relatively simple colligative property measurements hold considerable promise for free energy studies of multicomponent surfactant solutions. PMID:21504169

MacNeil, Jennifer A; Ray, Gargi Basu; Leaist, Derek G

2011-04-19

78

Pour point depressant made from the asphaltene component of thermally treated shale oil  

SciTech Connect

A product useful as a pour point depressant which comprises the asphaltene component of a thermally treated shale oil is disclosed, as is a process for making it, a method for using it and a concentrate and a composition containing it.

Jensen, H.P.

1980-05-06

79

Thermocouple observations of melting and freezing plateaus for metal-carbon eutectics between the copper and palladium points  

Microsoft Academic Search

Melting and freezing plateaus were observed with type-R thermocouples for the metal-carbon eutectics Pd-C, Ni-C, and Fe-C. For Pd-C, no apparent difference between the melting and freezing temperatures was observed at a heating\\/cooling rate of 3 °C\\/min. For Ni-C, the difference was 0.4 °C, and for Fe-C, 1.6 °C. The freezing temperature for Fe-C showed dependence on cooling rate, and

Y. Yamada; F. Sakuma; A. Ono

2000-01-01

80

Influence of surface groups of proteins on water studied by freezing\\/thawing hysteresis and infrared spectroscopy  

Microsoft Academic Search

The influence of proteins and solutes on hysteresis of freezing and melting of water was measured by infrared (IR) spectroscopy. Of the solutes examined, poly-l-arginine and flounder antifreeze protein produced the largest freezing point depression of water, with little effect on the melting temperature. Poly-l-lysine, poly-l-glutamate, cytochrome c and bovine serum albumin had less effect on the freezing of water.

Bogumil Zelent; Michael A. Bryan; Kim A. Sharp; Jane M. Vanderkooi

2009-01-01

81

Liposome fluidization and melting point depression by compressed and liquid n-alkanes  

Microsoft Academic Search

Fluidization and melting point depression of aqueous dipalmitoylphosphatidylcholine (DPPC, Tm?315K) liposomes by compressed\\/supercritical n-alkanes (C2 and C3; 0.8–20.7MPa) was quantified and compared to fluidization by liquid n-alkanes (C5–C10) using fluorescence anisotropy. The adsorption of ethane and propane into DPPC bilayers resulted in significant depression of the melting temperature (up to ?Tm=?16.2K at 7.0MPa ethane and propane). Pressure-dependent fluidization by gaseous

Geoffrey D. Bothun; Barbara L. Knutson; Herbert J. Strobel; Sue E. Nokes

2006-01-01

82

Synthesis and Evaluation of Some Polymeric Compounds as Pour Point Depressants and Viscosity Index Improvers for Lube Oil  

Microsoft Academic Search

In the present study, some polymeric additives were prepared and used as pour point depressants and as viscosity index improvers for lube oil via copolymerization of maleic anhydride and vinyl acetate with different esters of acrylic acid. The molecular weights of the prepared copolymers were determined by GPC. The efficiency of the prepared compounds as pour point depressant and viscosity

N. S. Ahmed; A. M. Nassar; R. M. Nasser; A. F. Khattab; A.-A. A. Abdel-Azim

2008-01-01

83

Radiometric observation of melting and freezing plateaus for a series of metal-carbon eutectic points in the range 1330 °C to 1950 °C  

Microsoft Academic Search

Melting and freezing plateaus were radiometrically observed for the metal-carbon eutectics Ni-C, Pd-C, Pt-C, and Ru-C, using graphite crucibles and black-body cavities. The graphite crucibles were able to withstand heat cycles without breaking. Since the crucible material is a component of the eutectic fixed-point material, the latter is inherently free of contamination from the crucible. The temperature differences between the

Y. Yamada; H. Sakate; F. Sakuma; A. Ono

1999-01-01

84

A new optimal control model for reproducing two-point reaching movements of human three-joint arm with wrist joint's freezing mechanism  

Microsoft Academic Search

A new optimal control model of human arms has been developed to simulate two-point reaching movement characteristics for human three-joint arms (shoulder, elbow, and wrist joints) and its fundamental performance has been clarified. The new model is formulated by extending the previous two-joint modified minimum torque-change model to a three-joint model with a freezing mechanism in its wrist joint and

Toshikazu Matsui

2009-01-01

85

Depression  

MedlinePLUS

... version of this page please turn Javascript on. Depression About Depression Click image for description Everyone feels blue or ... disorder," or "clinical depression." Click image for description Depression in Older Adults Important life changes that happen ...

86

Multifunctional Additives Viscosity Index Improvers, Pour Point Depressants and Dispersants for Lube Oil  

Microsoft Academic Search

In the present work, some polymeric additives based on styrene-maleic anhydride copolymer were prepared and evaluated as multifunction lube oil additives (viscosity index improvers, pour point depressants, and detergent-dispersant additives). The styrene-maleic anhydride copolymer reacted with different alcohols (dodecyl alcohol, hexadecyl alcohol, octadecyl alcohol, and docosanol) to prepare four different types of esters and aminated with different types of amines

A. A. A. Abdel Azim; A. M. Nasser; N. S. Ahmed; A. F. El Kafrawy; R. S. Kamal

2009-01-01

87

Effect of temperature of CO2 injection on the pH and freezing point of milks and creams.  

PubMed

The objectives of this study were to measure the impact of CO2 injection temperature (0 degree C and 40 degrees C) on the pH and freezing point (FP) of (a) milks with different fat contents (i.e., 0, 15, 30%) and (b) creams with 15% fat but different fat characteristics. Skim milk and unhomogenized creams containing 15 and 30% fat were prepared from the same batch of whole milk and were carbonated at 0 and 40 degrees C in a continuous flow CO2 injection unit (230 ml/min). At 0 degree C, milk fat was mostly solid; at 40 degrees C, milk fat was liquid. At the same total CO2 concentration with CO2 injection at 0 degree C, milk with a higher fat content had a lower pH and FP, while with CO2 injection at 40 degrees C, milks with 0%, 15%, and 30% fat had the same pH. This indicated that less CO2 was dissolved in the fat portion of the milk when the CO2 was injected at 0 degree C than when it was injected at 40 degrees C. Three creams, 15% unhomogenized cream, 15% butter oil emulsion in skim milk, and 15% vegetable oil emulsion in skim milk were also carbonated and analyzed as described above. Vegetable oil was liquid at both 0 and 40 degrees C. At a CO2 injection temperature of 0 degree C, the 15% vegetable oil emulsion had a slightly higher pH than the 15% butter oil emulsion and the 15% unhomogenized cream, indicating that the liquid vegetable oil dissolved more CO2 than the mostly solid milk fat and butter oil. No difference in the pH or FP of the 15% unhomogenized cream and 15% butter oil emulsion was observed when CO2 was injected at 0 degree C, suggesting that homogenization or physical dispersion of milk fat globules did not influence the amount of CO2 dissolved in milk fat at a CO2 injection temperature of 0 degree C. At a CO2 injection temperature of 40 degrees C and at the same total CO2 concentration, the 15% unhomogenized cream, 15% vegetable oil emulsion, and 15% butter oil emulsion had similar pH. At the same total concentration of CO2 in cream, injection of CO2 at low temperature (i.e., < 4 degrees C) may produce a better antimicrobial effect during refrigerated shelf life due to the higher concentration of CO2 in the skim portion of the cream. PMID:12778568

Ma, Y; Barbano, D M

2003-05-01

88

Osmotic Coefficients of Aqueous Solutions of Some Poly(oxyethylene) Glycols at the Freezing Point of Solution  

Microsoft Academic Search

Summary. The freezing temperatures of dilute aqueous solutions of some poly(oxyethylene) glycols ( PEG, HO–(CH 2CH 2O) n–H, n varying from 4 to 117) were measured over a solute to solvent mass ratio from 0.0100 to 0.3900. The second and third osmotic virial coefficient ( A 22 and A 222) of poly(oxyethylene) glycols in aqueous solution were determined. The molecular

Darja Rudan-Tasic; Cveto Klofutar

2004-01-01

89

Freezing point and solid-liquid interfacial free energy of Stockmayer dipolar fluids: A molecular dynamics simulation study  

NASA Astrophysics Data System (ADS)

Stockmayer fluids are a prototype model system for dipolar fluids. We have computed the freezing temperatures of Stockmayer fluids at zero pressure using three different molecular-dynamics simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature two-phase coexistence method, and the constant-pressure and constant-enthalpy two-phase coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with the dimensionless dipole moment ?*=1, 2, 3 is 0.656 +/- 0.001, 0.726 +/- 0.002, and 0.835 +/- 0.005, respectively. The freezing temperature increases with the dipolar strength. Moreover, for the first time, the solid-liquid interfacial free energies ? of the fcc (111), (110), and (100) interfaces are computed using two independent methods, namely, the cleaving-wall method and the interfacial fluctuation method. Both methods predict that the interfacial free energy increases with the dipole moment. Although the interfacial fluctuation method suggests a weaker interfacial anisotropy, particularly for strongly dipolar SM fluids, both methods predicted the same trend of interfacial anisotropy, i.e., ?100 > ?110 > ?111.

Wang, Jun; Apte, Pankaj A.; Morris, James R.; Zeng, Xiao Cheng

2013-09-01

90

Freezing point and solid-liquid interfacial free energy of Stockmayer dipolar fluids: A molecular dynamics simulation study.  

PubMed

Stockmayer fluids are a prototype model system for dipolar fluids. We have computed the freezing temperatures of Stockmayer fluids at zero pressure using three different molecular-dynamics simulation methods, namely, the superheating-undercooling method, the constant-pressure and constant-temperature two-phase coexistence method, and the constant-pressure and constant-enthalpy two-phase coexistence method. The best estimate of the freezing temperature (in reduced unit) for the Stockmayer (SM) fluid with the dimensionless dipole moment ?(*)=1,?2,?3 is 0.656 ± 0.001, 0.726 ± 0.002, and 0.835 ± 0.005, respectively. The freezing temperature increases with the dipolar strength. Moreover, for the first time, the solid-liquid interfacial free energies ? of the fcc (111), (110), and (100) interfaces are computed using two independent methods, namely, the cleaving-wall method and the interfacial fluctuation method. Both methods predict that the interfacial free energy increases with the dipole moment. Although the interfacial fluctuation method suggests a weaker interfacial anisotropy, particularly for strongly dipolar SM fluids, both methods predicted the same trend of interfacial anisotropy, i.e., ?100 > ?110 > ?111. PMID:24070303

Wang, Jun; Apte, Pankaj A; Morris, James R; Zeng, Xiao Cheng

2013-09-21

91

The Low-Temperature Handling of Navy Distillate Fuels. Phase III. The Effect of Pour-Point-Depressant Additives on Cloud-Point and Low-Temperature Fluidity.  

National Technical Information Service (NTIS)

The effect of six commercially available pour-point depressant additives on the cloud-point temperatures and 'Enjay Fluidities' of six distillate fuels was determined. Five of the six fuels were Navy Distillate types, the sixth was a Diesel Fuel, Marine. ...

E. W. White K. V. Nagy

1973-01-01

92

Cell Freeze Liquid Nitrogen Freezing Container  

Center for Biologics Evaluation and Research (CBER)

... Cell Freeze Liquid Nitrogen Freezing Container. Applicant: Charter Medical, Ltd. ... Product: Cell Freeze Liquid Nitrogen Freezing Container. ... More results from www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts

93

Depression  

Microsoft Academic Search

HEALTH ISSUE: Depression causes significant distress or impairment in physical, social, occupational and other key areas of functioning. Women are approximately twice as likely as men to experience depression. Psychosocial factors likely mediate the risks for depression incurred by biological influences. KEY FINDINGS: Data from the 1999 National Population Health Survey show that depression is more common among Canadian women,

Donna E. Stewart; Enza Gucciardi; Sherry L. Grace

2004-01-01

94

A molecular simulation study of freezing/melting phenomena for Lennard-Jones methane in cylindrical nanoscale pores  

SciTech Connect

A combination of grand canonical Monte Carlo and molecular dynamics simulation techniques are used to study the freezing and melting of Lennard-Jones methane in several different cylindrical pores. Two different types of pore wall are considered; a strongly attractive wall, and a weakly attractive wall, each with pore diameters in the range 1.5{endash}3.5 nm. Freezing point depression is observed in the case of the weakly attractive pores, in agreement with several experimental studies. Freezing point elevation is observed at the walls of the strongly attractive pore, but freezing point depression occurs at the center of such pores, due to geometrical constraints. {copyright} {ital 1997 American Institute of Physics.}

Maddox, M.W.; Gubbins, K.E. [School of Chemical Engineering, Cornell University, Ithaca, New York 14853 (United States)

1997-12-01

95

The relationship between latent trigger points and depression levels in healthy subjects.  

PubMed

Our purpose was to study the relationship between latent trigger points (LTrP) and levels of depression in healthy subjects. A total of 76 healthy subjects consisting of 40 men and 36 women (mean age, 25.4?±?4.8 years; age range, 19-42 years) from the School of Physical Therapy and Rehabilitation and the Orthopaedics and Traumatology Department of Istanbul University Medical Faculty were selected for the study. Latent trigger points on the scapular muscles of each subject were evaluated. The upper and middle trapezius, supraspinatus, serratus anterior, and rhomboideus muscles were examined respectively, by palpation with the thumb, to determine whether there was pain. The first group consisted of 30 subjects (20 men and 10 women; mean age, 24.2?±?5.02 years) who had previously been diagnosed as negative after an LTrP examination (control group), while the second group consisted of 28 subjects (12 men and 16 women; mean age, 23.6?±?2.24 years) who had been diagnosed with at least five LTrPs. The third group consisted of 18 subjects (8 men and 10 women; mean age, 26. 9?±?7.23 years) who had been diagnosed with more than five LTrPs. All groups were assessed, using the Beck Depression Inventory (BDI). The mean BDI value was found to be 8.0?±?4.2 in the first group, 10.3?±?3.4 in the second, and 28.5?±?4.8 in the third. A significant difference was found between the mean BDI values of the first and second groups and also between the first and third groups. The mean BDI values of the second and third groups were also found to be statistically significant (p?=?0.042). We observed a close relationship between the presence of LTrPs and depression levels in healthy people. PMID:22327279

Celik, Derya; Kaya Mutlu, Ebru

2012-02-11

96

Freezing Precipitation.  

National Technical Information Service (NTIS)

This technical note discusses three advection patterns favorable for freezing precipitation. Two graphs were developed based on 503 freezing precipitation occurrences during the past 11 years- a 1000- to 500-mb thickness graph and an 850-mb temperature gr...

E. M. Weber

1998-01-01

97

Depression  

MedlinePLUS

Depression is a serious medical illness that involves the brain. It's more than just a feeling of ... million people in the United States who have depression, the feelings do not go away. They persist ...

98

Depression  

MedlinePLUS

... to enjoy (including sex) Thinking about death or suicide Physical symptoms Changes in appetite (eating more than ... help prevent depression from coming back. Thoughts of suicide are common in people with depression. The risk ...

99

Melting Point Depression and Kinetic Effects of Cooling on Crystallization in Poly(vinylidene fluoride)Poly(methyl methacrylate) Mixtures  

Microsoft Academic Search

Thermal analysis of solution cast mixtures of poly(viny1idene fluoride) (PVF2) and poly(methy1 methacrylate) (PMMA) has been carried out with various programmed temperature profiles. Results from experi- ments conducted in a quasi-equilibrium state show that PVF:! crystallizes in the mixture upon cooling. Further- more, depressions were observed in the melting and the crystallization temperatures. The melting point depression phenomenon is found

T. Nishi; T. T. Wang

1975-01-01

100

Depression  

PubMed Central

Health Issue Depression causes significant distress or impairment in physical, social, occupational and other key areas of functioning. Women are approximately twice as likely as men to experience depression. Psychosocial factors likely mediate the risks for depression incurred by biological influences. Key Findings Data from the 1999 National Population Health Survey show that depression is more common among Canadian women, with an annual self-reported incidence of 5.7% compared with 2.9% in men. The highest rates of depression are seen among women of reproductive age. Predictive factors for depression include previous depression, feeling out of control or overwhelmed, chronic health problems, traumatic events in childhood or young adulthood, lack of emotional support, lone parenthood, and low sense of mastery. Although depression is treatable, only 43% of depressed women had consulted a health professional in 1998/99 and only 32.4% were taking antidepressant medication. People with lower education, inadequate income, and fewer contacts with a health professional were less likely to receive depression treatment. Data Gaps and Recommendations A better understanding of factors that increase vulnerability and resilience to depression is needed. There is also a need for the collection and analysis of data pertaining to: prevalence of clinical anxiety; the prevalence of depression band 12 months after childbirth factors contributing to suicide contemplation and attempts among adolescent girls, current treatments for depression and their efficacy in depressed women at different life stages; interprovincial variation in depression rates and hospitalizations and the impact and costs of depression on work, family, individuals, and society.

Stewart, Donna E; Gucciardi, Enza; Grace, Sherry L

2004-01-01

101

Depression  

MedlinePLUS

... smaller jobs that are easy to finish. Regular exercise may also help prevent depression or lift your mood if you are somewhat depressed. Older people who are depressed can gain mental as well as physical benefits from mild forms of exercise like walking outdoors or in shopping malls. Gardening, ...

102

Depression  

MedlinePLUS

... or suicide. Depression treatment usually includes a thorough evaluation, patient education, and self-help instructions, individual or group talk therapy and, when appropriate, the prescription of anti-depressant ... with a thorough evaluation to rule out an underlying medical condition or ...

103

Effects of temperatures near the freezing point on N2O emissions, denitrification and on the abundance and structure of nitrifying and denitrifying soil communities.  

PubMed

Climate warming in temperate regions may lead to decreased soil temperatures over winter as a result of reduced snow cover. We examined the effects of temperatures near the freezing point on N(2)O emissions, denitrification, and on the abundance and structure of soil nitrifiers and denitrifiers. Soil microcosms supplemented with NO3 - and/or NO3 - plus red clover residues were incubated for 120 days at -4 °C, -1 °C, +2 °C or +5 °C. Among microcosms amended with residues, N(2)O emission and/or denitrification increased with increasing temperature on Days 2 and 14. Interestingly, N(2)O emission and/or denitrification after Day 14 were the greatest at -1 °C. Substantial N(2) O emissions were only observed on Day 2 at +2 °C and +5 °C, while at -1 °C, N(2)O emissions were consistently detected over the duration of the experiment. Abundances of ammonia oxidizing bacteria (AOB) and archaea (AOA), Nitrospira-like bacteria and nirK denitrifiers were the lowest in soils at -4 °C, while abundances of Nitrobacter-like bacteria and nirS denitrifiers did not vary among temperatures. Community structures of nirK and nirS denitrifiers and Nitrobacter-like bacteria shifted between below-zero and above-zero temperatures. Structure of AOA and AOB communities also changed but not systematically among frozen and unfrozen temperatures. Results indicated shifts in some nitrifier and denitrifier communities with freezing and a surprising stimulation of N(2)O emissions at -1 °C when NO3 - and C are present. PMID:22882277

Wertz, Sophie; Goyer, Claudia; Zebarth, Bernie J; Burton, David L; Tatti, Enrico; Chantigny, Martin H; Filion, Martin

2012-08-29

104

Depression (PDQ)  

MedlinePLUS

General Information About Depression Key Points for This Section Depression is different from normal sadness. Some cancer patients may have a higher risk of depression. There are many medical conditions that can cause ...

105

Depression  

MedlinePLUS Videos and Cool Tools

... doctor can diagnose depression. The diagnosis includes a physical examination, a complete history of symptoms, and a ... history is essential. This is followed by a physical examination to help rule out other diseases that ...

106

State diagram of dates: Glass transition, freezing curve and maximal-freeze-concentration condition  

Microsoft Academic Search

The state diagram of Deglet Nour dates was developed using freezing curve, glass transition line, and maximal-freeze-concentration condition. Freezing points and glass transition temperature were measured by differential scanning calorimetry (DSC) as a function of water content. Freezing points were fitted to the Clausius–Clapeyron equation adjusted with un-freezable water, and glass transition was fitted to the Gordon–Taylor model. Glass transition

Nejib Guizani; Ghalib Said Al-Saidi; Mohammad Shafiur Rahman; Salwa Bornaz; Ahmed Ali Al-Alawi

2010-01-01

107

Autobiographical Memory and Depression in the Later Age: The Bump Is a Turning Point  

ERIC Educational Resources Information Center

|This preliminary study integrated previous findings of the distribution of autobiographical memories in the later age according to their age of occurrence, with the overgeneral memory bias predictive of depression. Twenty-five non-demented, Israeli participants between 65-89 years of age provided autobiographical memories to 4 groups of word cues…

Gidron, Yori; Alon, Shirly

2007-01-01

108

Autobiographical Memory and Depression in the Later Age: The Bump Is a Turning Point  

ERIC Educational Resources Information Center

This preliminary study integrated previous findings of the distribution of autobiographical memories in the later age according to their age of occurrence, with the overgeneral memory bias predictive of depression. Twenty-five non-demented, Israeli participants between 65-89 years of age provided autobiographical memories to 4 groups of word cues…

Gidron, Yori; Alon, Shirly

2007-01-01

109

Cloud Point Depression in Dilute Solutions of HEMA/DMAEMA Copolymers with Prescribed Composition Profiles and Gradient Strengths  

NASA Astrophysics Data System (ADS)

We have synthesized a random copolymer and gradient copolymers of hydroxyethyl methacrylate and dimethylaminoethyl methacrylate whose instantaneous compositions vary linearly and according to hyperbolic tangent (Tanh) functions along the backbones, all having similar molecular weights and overall compositions. The cloud point of the dilute solution of the random copolymer is 20.0^oC; the transparent-to-turbid transition occurs over 1.0^oC. Dilute solutions of linear gradient copolymers exhibit cloud point depressions of up to 3.5^oC and transition breadths of 1-3^oC compared to that of the random copolymer. The cloud points of dilute solutions of gradient copolymers with Tanh composition profiles are further suppressed by as much as 9.0^oC compared to that of the random copolymer. Our observations demonstrate the importance of monomer sequence distribution in altering the macroscopic solution properties of copolymers.

Gallow, Keith; Jhon, Young; Genzer, Jan; Loo, Yueh-Lin

2011-03-01

110

Evaluation of the MilkoScan FT 6000 milk analyzer for determining the freezing point of goat's milk under different analytical conditions.  

PubMed

The aim of this research was to evaluate the Milko-Scan FT 6000 (Foss Electric, Hillerød, Denmark) for determining the freezing point (FP) of goat's milk under different analytical conditions. The FP was determined in duplicate in 1,800 milk aliquots obtained from 45 bulk tank milk samples from 10 Murciano-Granadina goat herds, using the MilkoScan method and a reference thermistor cryoscopy method (Advanced Instrument Inc., Norwood, MA). Five different preservation strategies--no preservative, preservation with azidiol (0.006 or 0.018 g of sodium azide/100 mL), and preservation with bronopol (0.020 or 0.040 g/100 mL)--were then used to preserve the milk. For each preservation strategy, 8 different amounts of water were added (0, 1, 2, 3, 4, 5, 6, or 7% total volume). The results obtained with each method under these 40 analytical conditions were examined by comparison of means, comparison of the standard deviations of repeatability (s(r) and its relative value s(r)%), and a regression analysis. Under most analytical conditions, the FP was recorded as lower by the MilkoScan method, with a mean difference of 1.5 m degrees C compared with the reference method. Both methods showed similar repeatabilities (the overall s(r)% was 0.22% for the MilkoScan method and 0.20% for the reference method). In comparisons of the 2 methods, the highest regression coefficients were obtained with aliquots containing >3% added water. The best regression coefficients (0.85 to 1.02) were obtained for milk samples preserved with bronopol at 0.020 g/100 mL. These results allow the MilkoScan method to be used with goat's milk for screening purposes. The factors of added water, preservative, analytical method, lactose concentration, and the effect of the bulk tank milk sample within each lactose group contributed significantly to the observed variation in FP. For practical purposes, either of the bronopol concentrations could be used when determining the FP of goat's milk with the methods tested. However, the increase in the concentration of sodium azide in the azidiol formula contributed to an important reduction in the FP recorded. Thus, the type and concentration of preservative should be taken into account when interpreting FP values. PMID:17582097

Sánchez, A; Sierra, D; Luengo, C; Corrales, J C; de la Fe, C; Morales, C T; Contreras, A; Gonzalo, C

2007-07-01

111

Curvature-dependent metastability of the solid phase and the freezing-melting hysteresis in pores.  

PubMed

We recapitulate and generalize the concept of the freezing-melting hysteresis that attributes this phenomenon to a free-energy barrier between metastable and stable states of pore-filling material. In a phenomenological description, we show that under commonly encountered conditions, this renders the freezing-point depression DeltaTf defined by the surface-to-volume ratio S/V, whereas the melting-point depression DeltaTm, by the mean curvature kappa of the pore surface, with DeltaTm/DeltaTf =2kappa(V/S). Employing 1H NMR cryoporometry, we experimentally demonstrate the linear correlation between DeltaTm and DeltaTf for several liquids with different DeltaTf,m imbibed in controlled pore glasses. The results compare favorably to the morphological properties of the glasses determined by other techniques. Our findings suggest a simple method for analyzing the pore morphology from the observed phase transition temperatures. PMID:16486162

Petrov, Oleg; Furó, István

2006-01-31

112

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

ERIC Educational Resources Information Center

|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…

Tellinghuisen, Joel

2010-01-01

113

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

ERIC Educational Resources Information Center

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…

Tellinghuisen, Joel

2010-01-01

114

Liquidus Temperature Depression in Cryolitic Melts  

NASA Astrophysics Data System (ADS)

The electrolyte in Hall-Héroult cells for the manufacture of primary aluminum nominally contains only cryolite (Na3AlF6) with additions of AlF3, CaF2, and Al2O3. However, impurities are present, entering the process with the feedstock. The effect on the liquidus temperature by the impurities cannot be calculated correctly by the well-known equation for freezing-point depression in binary systems simply because the electrolyte cannot be regarded as a binary system. By extending the equation for freezing-point depression to the ternary system NaF-AlF3-B, it appeared that the acidity of the impurity B plays a major role. Some calculations were made using an ideal Temkin model, and for most types of impurities, the effect on the liquidus temperature will be larger in an industrial electrolyte than what can be estimated from the equation for freezing-point depression in cryolite. Experimental data on the liquidus temperature in the system Na3AlF6-AlF3-Al2O3-CaF2-MgF2 show that the effect of MgF2 on the liquidus temperature increases strongly with decreasing NaF/AlF3 molar ratio, and it is suggested that MgF2 forms an anion complex, probably MgF{4/2-}.

Solheim, Asbjørn

2012-08-01

115

Freeze Concentration and Its Recent Development  

NASA Astrophysics Data System (ADS)

This article concerns freeze concentration and its recent development. Freeze concentration enables to remove water from aqueous solutions including volatile and heat-sensitive components with less damage to the concentrated solution because of the operation at lower temperature near the freezing point with possibly no gas-liquid boundary. Moreover, the lower latent heat accompanied with ice crystallization provides a possibility of the operation with lower energy consumption. Recently freeze concentration has been applied to the wastewater treatment field. First the principle of freeze concentration will be addressed. Second applications of freeze concentration to the wastewater treatment field will be reviewed, including our recent works. Finally prospective views of freeze concentration will be given.

Wakisaka, Minato; Shirai, Yoshihito

116

Narrow depression in the density of states at the Dirac point in disordered graphene  

NASA Astrophysics Data System (ADS)

The electronic properties of noninteracting particles moving on a two-dimensional bricklayer lattice are investigated numerically. In particular, the influence of disorder in form of a spatially varying random magnetic flux is studied. In addition, a strong perpendicular constant magnetic field B is considered. The density of states ?(E) goes to zero for E?0 as in the ordered system but with a much steeper slope. This happens for both cases: at the Dirac point for B=0 and at the center of the central Landau band for finite B . Close to the Dirac point, the dependence of ?(E) on the system size, on the disorder strength, and on the constant magnetic flux density is analyzed and fitted to an analytical expression proposed previously in connection with the thermal quantum-Hall effect. Additional short-range on-site disorder completely replenishes the indentation in the density of states at the Dirac point.

Schweitzer, L.

2009-12-01

117

Entropy, Disorder, and Freezing  

NASA Astrophysics Data System (ADS)

It is argued that the usual view that entropy is a measure of "disorder" is problematic and that there exist systems at high density, for which packing considerations dominate, where a spatially ordered state has a higher entropy than a disordered one. A classic example is a system of hard-sphere atoms, for which freezing is known to be purely entropy driven. Such a model has relevance to the real world, since it provides a good qualitative (and nearly quantitative) description of solid-liquid coexistence in simple systems such as argon. An analogy based on the packing of suitcases is given to illustrate the main point. A simple classroom demonstration is also described in which an analog simulation of the freezing of hard particles is performed.

Laird, Brian B.

1999-10-01

118

Melting point depression of Al clusters generated during the early stages of film growth: Nanocalorimetry measurements  

SciTech Connect

This work investigates the thermodynamic properties of small structures of Al using an ultrasensitive thin-film differential scanning calorimeter. Al thin films were deposited onto a Si{sub 3}N{sub 4} surface via thermal evaporation over a range of thicknesses from 6 to 50 {Angstrom}. The Al films were discontinuous and formed nanometer-sized clusters. Calorimetry measurements demonstrated that the melting point of the clusters is lower than the value for bulk Al. We show that the melting point of the clusters is size dependent, decreasing by as much as 140{degree}C for 2 nm clusters. The results have relevance in several key areas for Al metallization in micro-electronics including the early stages of film growth and texture formation, the Al reflow process, and the dimensional stability of high aspect ratio Al lines. {copyright} {ital 1998 American Institute of Physics.}

Lai, S.L.; Carlsson, J.R.; Allen, L.H. [Department of Materials Science and Engineering, University of Illinois at Urbana--Champaign, Urbana, Illinois 61801 (United States)

1998-03-01

119

Stability against freezing of aqueous solutions on early Mars  

NASA Astrophysics Data System (ADS)

Many features of the Martian landscape are thought to have been formed by liquid water flow and water-related mineralogies on the surface of Mars are widespread and abundant. Several lines of evidence, however, suggest that Mars has been cold with mean global temperatures well below the freezing point of pure water. Martian climate modellers considering a combination of greenhouse gases at a range of partial pressures find it challenging to simulate global mean Martian surface temperatures above 273K, and local thermal sources cannot account for the widespread distribution of hydrated and evaporitic minerals throughout the Martian landscape. Solutes could depress the melting point of water in a frozen Martian environment, providing a plausible solution to the early Mars climate paradox. Here we model the freezing and evaporation processes of Martian fluids with a composition resulting from the weathering of basalts, as reflected in the chemical compositions at Mars landing sites. Our results show that a significant fraction of weathering fluids loaded with Si, Fe, S, Mg, Ca, Cl, Na, K and Al remain in the liquid state at temperatures well below 273K. We tested our model by analysing the mineralogies yielded by the evolution of the solutions: the resulting mineral assemblages are analogous to those actually identified on the Martian surface. This stability against freezing of Martian fluids can explain saline liquid water activity on the surface of Mars at mean global temperatures well below 273K.

Fairén, Alberto G.; Davila, Alfonso F.; Gago-Duport, Luis; Amils, Ricardo; McKay, Christopher P.

2009-05-01

120

Refrigeration Requirements for Ice Cream Freezing1  

Microsoft Academic Search

The heat removed from an ice cream mix during freezing is a function of several variables with composition predominating. This investigation compared experimental calorimetric results with predicted refrig- eration requirements. The predictions were obtained by adding the contributions of sensible heat of mix above the initial freezing point, sensible heat of unfrozen mix portion, latent heat and sensible heat of

D. R. Heldman; T. I. Hedrick

1970-01-01

121

Freezing precipitation in Canada  

Microsoft Academic Search

Renewed interest in freezing precipitation processes and their cause have resulted in a requirement for an updated, detailed climatology of freezing precipitation in Canada. Previous work in this area was very limited in terms of the period of record and the extent of the analysis.In this study national maps were prepared of occurrence frequencies of freezing rain, freezing drizzle and

R. A. Stuart; G. A. Isaac

1999-01-01

122

Molecular biology of freezing tolerance.  

PubMed

Winter survival for many kinds of animals involves freeze tolerance, the ability to endure the conversion of about 65% of total body water into extracellular ice and the consequences that freezing imposes including interruption of vital processes (e.g., heartbeat and breathing), cell shrinkage, elevated osmolality, anoxia/ischemia, and potential physical damage from ice. Freeze-tolerant animals include various terrestrially hibernating amphibians and reptiles, many species of insects, and numerous other invertebrates inhabiting both terrestrial and intertidal environments. Well-known strategies of freezing survival include accumulation of low molecular mass carbohydrate cryoprotectants (e.g., glycerol), use of ice nucleating agents/proteins for controlled triggering of ice growth and of antifreeze proteins that inhibit ice recrystallization, and good tolerance of anoxia and dehydration. The present article focuses on more recent advances in our knowledge of the genes and proteins that support freeze tolerance and the metabolic regulatory mechanisms involved. Important roles have been identified for aquaporins and transmembrane channels that move cryoprotectants, heat shock proteins and other chaperones, antioxidant defenses, and metabolic rate depression. Genome and proteome screening has revealed many new potential targets that respond to freezing, in particular implicating cytoskeleton remodeling as a necessary facet of low temperature and/or cell volume adaptation. Key regulatory mechanisms include reversible phosphorylation control of metabolic enzymes and microRNA control of gene transcript expression. These help to remodel metabolism to preserve core functions while suppressing energy expensive metabolic activities such as the cell cycle. All of these advances are providing a much more complete picture of life in the frozen state. PMID:23897687

Storey, Kenneth B; Storey, Janet M

2013-07-01

123

Size-dependent freezing of n-alcohols in silicon nanochannels  

NASA Astrophysics Data System (ADS)

We present a study on the phase behavior of several linear n-alcohols (heptanol, nonanol and undecanol) in their bulk state as well as confined in mesoporous silicon. We were able to vary the mean pore radii of the nanochannels from r = 3.5 nm to 7 nm and to determine the respective temperatures of the freezing and melting transitions using infrared and dielectric spectroscopy. The smaller the chain length the lower the freezing point, both in the bulk and in the confined state. Under confinement the freezing temperature decreases by up to 28 K compared to the bulk value. In accordance with the Gibbs-Thompson model the lowering is proportional to the inverse pore radius, ?Tfr ? 1/r. Moreover, the ratio of freezing temperature depression to melting temperature depression is close to the theoretical value of ?Tfr/?Tmelt = 3/2. The spectra also indicate a structural change: while the solid bulk alcohols are a polycrystalline mixture of the orthorhombic ?- and monoclinic ?-form, geometrical confinement forces the alcohol-chains into the more simple orthorhombic structure. In addition, a part of the material does not crystallize. Such an additional amorphous phase seems to be a logical consequence of the size mismatch between molecular crystals and irregular shaped pores.

Berwanger, R.; Schumacher, Ch.; Huber, P.; Pelster, R.

2010-10-01

124

Fish antifreeze protein and the freezing and recrystallization of ice.  

PubMed

Antifreeze glycopeptide and peptides from the blood of polar fishes prevent the growth of ice crystals in water at temperatures down to approximately 1 degree C below freezing point, but do not appreciably influence the equilibrium freezing point. This freezing point hysteresis must be a disequilibrium effect, or it would violate Gibbs' phase rule, but the separate freezing and melting points are experimentally very definite: ice neither melts nor freezes perceptibly within the 'hysteresis gap', for periods of hours or days. We report here unusual crystal faces on ice crystals grown from solutions of very low concentrations of the anti-freeze glycopeptides and peptides. This is a clue to the mechanism of freezing inhibition, and it may be the basis of a simple, very sensitive test for antifreeze material. Very low concentrations of the antifreeze protein are also remarkably effective in preventing the recrystallization of ice. PMID:6700733

Knight, C A; DeVries, A L; Oolman, L D

125

Avoid freeze-up of steam traps and their piping  

Microsoft Academic Search

This article addresses the problem of keeping steam traps free of ice in cold weather. The topics of the article include piping configurations and trap types that contribute to freezing, freeze damage, obstructions in piping, insulation of lines to retard freezing, common manifolds for heating of condensate, draining of low points, temperature-actuated devices, and water hammer damage.

OKeefe

1993-01-01

126

Avoid freeze-up of steam traps and their piping  

SciTech Connect

This article addresses the problem of keeping steam traps free of ice in cold weather. The topics of the article include piping configurations and trap types that contribute to freezing, freeze damage, obstructions in piping, insulation of lines to retard freezing, common manifolds for heating of condensate, draining of low points, temperature-actuated devices, and water hammer damage.

O'Keefe, W.

1993-12-01

127

Vacuum Freezing Multiple Phase Transformation Process Investigation.  

National Technical Information Service (NTIS)

The Vacuum Freezing Multiple Phase Transformation (VFMPT) Process accomplishes vapor liquefaction by desublimation of the vapor on a refrigerated surface, production of a second water vapor of higher temperature than the melting point of ice, and then dir...

C. Y. Cheng W. C. Cheng

1986-01-01

128

Cryoprotective dehydration and the resistance to inoculative freezing in the Antarctic midge, Belgica antarctica.  

PubMed

During winter, larvae of the Antarctic midge, Belgica antarctica (Diptera, Chironomidae), must endure 7-8 months of continuous subzero temperatures, encasement in a matrix of soil and ice, and severely desiccating conditions. This environment, along with the fact that larvae possess a high rate of water loss and are extremely tolerant of desiccation, may promote the use of cryoprotective dehydration as a strategy for winter survival. This study investigates the capacity of larvae to resist inoculative freezing and undergo cryoprotective dehydration at subzero temperatures. Slow cooling to -3 degrees C in an environment at equilibrium with the vapor pressure of ice reduced larval water content by approximately 40% and depressed the body fluid melting point more than threefold to -2.6 degrees C. This melting point depression was the result of the concentration of existing solutes (i.e. loss of body water) and the de novo synthesis of osmolytes. By day 14 of the subzero exposure, larval survival was still >95%, suggesting larvae have the capacity to undergo cryoprotective dehydration. However, under natural conditions the use of cryoprotective dehydration may be constrained by inoculative freezing as result of the insect's intimate contact with environmental ice. During slow cooling within a substrate of frozen soil, the ability of larvae to resist inoculative freezing and undergo cryoprotective dehydration was dependent upon the moisture content of the soil. As detected by a reduction of larval water content, the percentage of larvae that resisted inoculative freezing increased with decreasing soil moisture. These results suggest that larvae of the Antarctic midge have the capacity to resist inoculative freezing at relatively low soil moisture contents and likely undergo cryoprotective dehydration when exposed to subzero temperatures during the polar winter. PMID:18245628

Elnitsky, Michael A; Hayward, Scott A L; Rinehart, Joseph P; Denlinger, David L; Lee, Richard E

2008-02-01

129

Freezing and anoxia tolerance of slugs: a metabolic perspective  

Microsoft Academic Search

Freezing survival was assessed in three species of terrestrial slugs, a holarctic but native North American species, Deroceras laeve, and two species introduced from Europe, D. reticulatum and Arion\\u000a circumscriptus. The introduced species showed very poor freezing survival. Supercooling points of the introduced species were quite high\\u000a (??3°C) and their freezing survival was very poor, limited to short-term freezing at

Kenneth B. Storey; Janet M. Storey; Thomas A. Churchill

2007-01-01

130

Poromechanics of freezing materials  

NASA Astrophysics Data System (ADS)

When subjected to a uniform cooling below the freezing point a water-infiltrated porous material undergoes a cryo-deformation resulting from various combined actions: (i) the difference of density between the liquid water and the ice crystal, which results in the initial build-up of an in-pore pressure at the onset of crystallization; (ii) the interfacial effects arising between the different constituents, which eventually govern the crystallization process in connection with the pore access radius distribution; (iii) the drainage of the liquid water expelled from the freezing sites towards the air voids; (iv) the cryo-suction process, which drives liquid water towards the already frozen pores as the temperature further decreases; (v) the thermomechanical coupling between the solid matrix, the liquid water and the ice crystal. We work out a comprehensive theory able to encompass this whole set of actions. A macroscopic approach first provides the constitutive equations of freezing poroelastic materials, including the interfacial energy effects. This approach reveals the existence of a thermodynamic state function—namely the liquid saturation degree as a function of the temperature only. The macroscopic ice-dependent poroelastic properties are then upscaled from the knowledge of the elastic properties of the solid matrix, of the pore access radius distribution, and of the capillary curve. The theory is finally illustrated by analysing quantitatively the effects of the cooling rate and of the pore radius distribution upon the cryo-deformation of water-infiltrated porous materials. The theory succeeds in accounting for the experimentally observed shrinkage of embedded air voids, while predicting the partial melting of the ice already formed when the cooling suddenly stops.

Coussy, Olivier

2005-08-01

131

Influence of surface groups of proteins on water studied by freezing/thawing hysteresis and infrared spectroscopy.  

PubMed

The influence of proteins and solutes on hysteresis of freezing and melting of water was measured by infrared (IR) spectroscopy. Of the solutes examined, poly-L-arginine and flounder antifreeze protein produced the largest freezing point depression of water, with little effect on the melting temperature. Poly-L-lysine, poly-L-glutamate, cytochrome c and bovine serum albumin had less effect on the freezing of water. Small compounds used to mimic non-polar (trimethylamine N-oxide, methanol), positively charged (guanidinium chloride, NH(4)Cl, urea) and negatively charged (Na acetate) groups on protein surfaces were also examined. These molecules and ions depress water's freezing point and the melting profiles became broad. Since infrared absorption measures both bulk solvent and solvent bound to the solutes, this result is consistent with solutes interacting with liquid water. The amide I absorption bands of antifreeze protein and poly-L-arginine do not detectably change with the phase transition of water. An interpretation is that the antifreeze protein and poly-L-arginine order liquid water such that the water around the group is ice-like. PMID:19251353

Zelent, Bogumil; Bryan, Michael A; Sharp, Kim A; Vanderkooi, Jane M

2009-02-14

132

A Model for Prediction of Shrinkage Defects in Long and Short Freezing Range Materials  

Microsoft Academic Search

The aim of the model presented in this paper is to capture the difference in solidification behaviour of long and short freezing materials. The shrinkage defects in short freezing materials tends to be internal, as porosity, while in long freezing materials these defects tend to be external in the form of surface depressions. To achieve this, a pressure drop based

A. Reis; Zhi An Xu; J. F. Duarte; A. D. Santos; Y. Houbaert

2007-01-01

133

Modeling of shrinkage defects during solidification of long and short freezing materials  

Microsoft Academic Search

The aim of the model presented in this paper is to capture the difference in solidification behavior of long and short freezing materials. The shrinkage defects in short freezing materials tends to be internal, as porosity, while in long freezing materials these defects tend to be external in the form of surface depressions. To achieve this, a pressure drop based

A. Reis; Y. Houbaert; Zhian Xu; Rob Van Tol; A. D. Santos; J. F. Duarte; A. B. Magalhães

2008-01-01

134

Characterisation of the nanoporous structure of collagen-glycosaminoglycan hydrogels by freezing-out of bulk and bound water.  

PubMed

The nanoporous structure of collagen-glycosaminoglycan (CG) hydrogels was studied using 1H NMR spectroscopy and thermally stimulated depolarisation (TSD) current with layer-by-layer freezing-out of bulk and interfacial water. The depression of the freezing point of water is related to the size of the nanopore, to which it is confined. Changes in the Gibbs free energy of the unfrozen interfacial water are related to the amount of bound water in the hydrogel matrix and to the re-arrangement of the 3D network structure of the biopolymer. Analysis of the thermodynamic properties of bulk and interfacial water using the layer-by-layer freezing-out technique combined with NMR and TSDC provides valuable information about the structural features of CG hydrogels that can be used for characterisation of different types of hydrogels and soft tissue scaffolds, artificial skin substitutes and other biomaterials. PMID:16519934

Mikhalovska, Lyuba I; Gun'ko, Vlad M; Turov, Vlad V; Zarko, Vlad I; James, Stuart L; Vadgama, Pankaj; Tomlins, Paul E; Mikhalovsky, Sergey Victorovich

2006-03-07

135

Study on the Realization of Indium Point  

NASA Astrophysics Data System (ADS)

Indium point cells are fabricated using ingots of various forms from a variety of sources (manufacturers). Using these cells, newly built indium point furnaces are evaluated and their reliability is confirmed. The indium point realizations based on the single solid-liquid method (SSL method) and multi solid-liquid method (MSL method) are evaluated. The effect of impurities in the ingots is evaluated from the dependency of the slope of the freezing curve on the change in furnace temperature, the indium point depression based on the impurity analysis, and the cell comparison. The results show equality among the cells. Based on the results obtained, the uncertainty in realizing the indium point using the described indium point cells and indium point furnaces is estimated. The new uncertainty budget introduces uncertainties coming from plateau repeatability and chemical impurity derived by the present work, the values of which are significantly lower than those adopted in the current calibration service.

Widiatmo, Januarius V.; Yamazawa, Kazuaki; Satou, Kouichi; Tamba, Jun; Arai, Masaru

136

Development of certified reference materials of high-purity volatile organic compounds: purity assay by the freezing-point depression method  

Microsoft Academic Search

For accurate measurement of concentrations of substances by instrumental analysis, reliable calibration standards are needed.\\u000a In Japan, national reference materials are supplied under the national standards dissemination system named the Japan Calibration\\u000a Service System (JCSS). In JCSS, calibration standards for the analysis of environmental pollutants are supplied. For the traceability\\u000a to the SI of reference materials for calibration in JCSS,

Yoshitaka Shimizu; Yoko Ohte; Xinnu Bao; Satoko Otsuka; Yuko Kitamaki; Keiichiro Ishikawa; Toshihide Ihara; Kenji Kato

2008-01-01

137

KEY COMPARISON: Final report on comparison COOMET.T-K3: Regional comparisons of the national standards of temperature in the range from the triple point of water to the freezing temperature of zinc  

NASA Astrophysics Data System (ADS)

The COOMET.T-K3 comparison is the regional comparison of the defining fixed points realization in the range from the triple point of water to the freezing point of zinc. Four national metrology institutes—VNIIM (pilot), SMU, BelGIM and NNC IM—took part in the COOMET regional comparisons. At the first stage the cells of fixed points of the national metrology institutes were used as transfer standards. They were compared with the VNIIM cells by means of standard platinum resistance thermometers using the VNIIM standard setups and equipment. At the second stage the equivalence of realization of the fixed points at the national institutes was estimated. A standard platinum resistance thermometer SPRT (25 ohm), manufactured at VNIIM, was used as a transfer standard. The degree of equivalence of the measurement standard of the national metrology institutes participating in the COOMET comparison is determined relative to the reference values of the CCT-K3 through the measurement results received in the linking national metrology institutes, VNIIM and SMU, which took part in both comparisons. The values 'ARV' of K3 were assumed as the reference values. The report presents the results of this comparison and gives detailed information about the method of estimation of the degree of equivalence of NMI standards and its uncertainty. 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).

Pokhodun, A. I.; Ivanova, A. G.

2008-01-01

138

To freeze or not to freeze: adaptations for overwintering by hatchlings of the North American painted turtle.  

PubMed

Many physiologists believe that hatchling painted turtles (Chrysemys picta) provide a remarkable, and possibly unique, example of 'natural freeze-tolerance' in an amniotic vertebrate. However, the concept of natural freeze-tolerance in neonatal painted turtles is based on results from laboratory studies that were not placed in an appropriate ecological context, so the concept is suspect. Indeed, the weight of current evidence indicates that hatchlings overwintering in the field typically withstand exposure to ice and cold by avoiding freezing altogether and that they do so without benefit of an antifreeze to depress the equilibrium freezing point for bodily fluids. As autumn turns to winter, turtles remove active nucleating agents from bodily fluids (including bladder and gut), and their integument becomes a highly efficient barrier to the penetration of ice into body compartments from frozen soil. In the absence of a nucleating agent or a crystal of ice to 'catalyze' the transformation of water from liquid to solid, the bodily fluids remain in a supercooled, liquid state. The supercooled animals nonetheless face physiological challenges, most notably an increased reliance on anaerobic metabolism as the circulatory system first is inhibited and then caused to shut down by declining temperature. Alterations in acid/base status resulting from the accumulation of lactic acid may limit survival by supercooled turtles, and sublethal accumulations of lactate may affect behavior of turtles after the ground thaws in the spring. The interactions among temperature, circulatory function, metabolism (both aerobic and anaerobic), acid/base balance and behavior are fertile areas for future research on hatchlings of this model species. PMID:15277545

Packard, Gary C; Packard, Mary J

2004-08-01

139

Supercooled water behavior inside polymer electrolyte fuel cell cross-section below freezing temperature  

Microsoft Academic Search

This study investigated the phenomenon of water freezing below freezing point in polymer electrolyte fuel cells (PEFCs). To understand the details of water freezing phenomena inside a PEFC, a system capable of cross-sectional imaging inside the fuel cell with visible and infrared images was developed. Super-cooled water freezing phenomena were observed under different gas purge conditions. The present test confirmed

Y. Ishikawa; H. Hamada; M. Uehara; M. Shiozawa

2008-01-01

140

Rapid determination of vial heat transfer parameters using tunable diode laser absorption spectroscopy (TDLAS) in response to step-changes in pressure set-point during freeze-drying.  

PubMed

The purpose of this study was to perform a rapid determination of vial heat transfer parameters, that is, the contact parameter K(cs) and the separation distance l(v), using the sublimation rate profiles measured by tunable diode laser absorption spectroscopy (TDLAS). In this study, each size of vial was filled with pure water followed by a freeze-drying cycle using a LyoStar II dryer (FTS Systems) with step-changes of the chamber pressure set-point at to 25, 50, 100, 200, 300, and 400 mTorr. K(cs) was independently determined by nonlinear parameter estimation using the sublimation rates measured at the pressure set-point of 25 mTorr. After obtaining K(cs), the l(v) value for each vial size was determined by nonlinear parameter estimation using the pooled sublimation rate profiles obtained at 25 to 400 mTorr. The vial heat transfer coefficient K(v), as a function of the chamber pressure, was readily calculated, using the obtained K(cs) and l(v) values. It is interesting to note the significant difference in K(v) of two similar types of 10 mL Schott tubing vials, primary due to the geometry of the vial-bottom, as demonstrated by the images of the contact areas of the vial-bottom. PMID:18683861

Kuu, Wei Y; Nail, Steven L; Sacha, Gregory

2009-03-01

141

Freezing of the thawed zone around a well in frozen soils taking into account the pressure-dependence of the temperature of freezing  

NASA Astrophysics Data System (ADS)

The effects of taking into account the drop in the freezing point of water in the calculation of the pressures of retrograde freezing, arising during idle time and temporary shut-down of wells in frozen soils, are analyzed.

Dubina, M. M.; Krasovitskii, B. A.

1985-01-01

142

Optimal cutoff point of the Hamilton Rating Scale for Depression according to normal levels of social and occupational functioning  

Microsoft Academic Search

The main goal in the treatment of major depressive disorder (MDD) is to achieve remission, defined as the resolution of symptoms and the return to normal levels of functionality. However, the clinical assessment of remission is usually merely based on scores of symptomatic rating scales. One of the most widely used scales to measure remission is the HAM-D17, in which

Irene Romera; Víctor Pérez; José Manuel Menchón; Pepa Polavieja; Inmaculada Gilaberte

2011-01-01

143

Surface freezing of n-octane nanodroplets  

NASA Astrophysics Data System (ADS)

Surface freezing, at temperatures up to a few degrees above the equilibrium melting point, has been observed for intermediate chain length (16<= i<= 50) n-alkanes [B. M. Ocko, X. Z. Wu, E. B. Sirota, S. K. Sinha, O. Gang and M. Deutsch, Phys. Rev. E, 1997, 55, 3164-3182]. Our recent experimental results suggest that surface freezing is also the first step when highly supercooled nanodroplets of n-octane crystallize. Our data yield surface and bulk nucleation rates on the order of ~1015/cm2.s and ~1022/cm3.s, respectively. Complementary molecular dynamics simulations also show that the surface of the droplet freezes almost immediately, and freezing of the remainder of the droplet progresses in a layer-by-layer manner.

Modak, Viraj; Pathak, Harshad; Thayer, Mitchell; Singer, Sherwin; Wyslouzil, Barbara

2013-05-01

144

Hatchling turtles survive freezing during winter hibernation.  

PubMed Central

Hatchlings of the painted turtle (Chrysemys picta marginata) are unique as the only reptile and highest vertebrate life form known to tolerate the natural freezing of extracellular body fluids during winter hibernation. Turtles survived frequent exposures to temperatures as low as -6 degrees C to -8 degrees C in their shallow terrestrial nests over the 1987-1988 winter. Hatchlings collected in April 1988 had a mean supercooling point of -3.28 +/- 0.24 degrees C and survived 24 hr of freezing at -4 degrees C with 53.4% +/- 1.98% of total body water as ice. Recovery appeared complete after 20 hr of thawing at 3 degrees C. However, freezing at -10.9 degrees C, resulting in 67% ice, was lethal. A survey of possible cryoprotectants revealed a 2- to 3-fold increase in glucose content of liver and blood and a 3-fold increase in blood glycerol in response to freezing. Although quantitatively low, these responses by spring turtles strongly indicate that these may be the winter-active cryoprotectants. The total amino acid pool of blood also increased 2.25-fold in freezing-exposed turtles, and taurine accounted for 52% of the increase. Most organs accumulated high concentrations of lactate during freezing, a response to the ischemic state imposed by extracellular freezing. Changes in glycogen phosphorylase activity and levels of glucose 6-phosphate and fructose 2,6-bisphosphate were also consistent with a dependence on anaerobic glycolysis during freezing. Studies of the molecular mechanisms of natural freeze tolerance in these turtles may identify protective strategies that can be used in mammalian organ cryopreservation technology.

Storey, K B; Storey, J M; Brooks, S P; Churchill, T A; Brooks, R J

1988-01-01

145

Polymerization with freezing  

Microsoft Academic Search

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

E. Ben-Naim; P. L. Krapivsky

2005-01-01

146

The Freezing Bomb  

ERIC Educational Resources Information Center

|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.…

Mills, Allan

2010-01-01

147

Home Freezing of Seafoods.  

National Technical Information Service (NTIS)

Significant advances in freezing technology have been made within the past six years. Information is given on the selection of seafood for home freezing, for its preparation, packaging and storing, and finally on the proper use of the frozen product. Thre...

M. E. Waters

1974-01-01

148

Charge-Charge Liquid Structure Factor and the Freezing of Alkali Halides  

Microsoft Academic Search

The peak height of the charge-charge liquid structure factor SQQ in molten alkali halides is proposed as a criterion for freezing. Available data on molten alkali chlorides, when extrapolated to the freezing point suggests SQQ ? 5.

N. H. March; M. P. Tosi

1980-01-01

149

Melting and freezing of water in cylindrical silica nanopores.  

PubMed

Freezing and melting of H(2)O and D(2)O in the cylindrical pores of well-characterized MCM-41 silica materials (pore diameters from 2.5 to 4.4 nm) was studied by differential scanning calorimetry (DSC) and (1)H NMR cryoporometry. Well-resolved DSC melting and freezing peaks were obtained for pore diameters down to 3.0 nm, but not in 2.5 nm pores. The pore size dependence of the melting point depression DeltaT(m) can be represented by the Gibbs-Thomson equation when the existence of a layer of nonfreezing water at the pore walls is taken into account. The DSC measurements also show that the hysteresis connected with the phase transition, and the melting enthalpy of water in the pores, both vanish near a pore diameter D* approximately equal to 2.8 nm. It is concluded that D* represents a lower limit for first-order melting/freezing in the pores. The NMR spin echo measurements show that a transition from low to high mobility of water molecules takes place in all MCM-41 materials, including the one with 2.5 nm pores, but the transition revealed by NMR occurs at a higher temperature than indicated by the DSC melting peaks. The disagreement between the NMR and DSC transition temperatures becomes more pronounced as the pore size decreases. This is attributed to the fact that with decreasing pore size an increasing fraction of the water molecules is situated in the first and second molecular layers next to the pore wall, and these molecules have slower dynamics than the molecules in the core of the pore. PMID:18825292

Jähnert, S; Vaca Chávez, F; Schaumann, G E; Schreiber, A; Schönhoff, M; Findenegg, G H

2008-08-13

150

Thermophysical Properties of SweetPotato Puree at Freezing and Refrigeration Temperatures  

Microsoft Academic Search

The thermophysical properties (initial freezing point, unfreezable water, enthalpy of freezing, and specific heat) of alginate-restructured sweet potato (SP) puree at freezing and refrigeration temperatures were determined using differential scanning calorimetry. Restructuring of SP puree increased the amount of unfreezable (bound) water in the puree from 0.44 g H2O\\/g solids to about 0.56 g H2O\\/g solids and reduced the freezing point from

O. O. Fasina

2005-01-01

151

Thermal Analysis of the Heater-Induced Realization of the Tin Fixed Point  

NASA Astrophysics Data System (ADS)

In this article, work concerning the thermal analysis of the tin fixed-point is reported. First, the development of a new fixed-point furnace is described. Improvements in the design of the furnace and in the control system enable measurement of the heater power during the phase change. The furnace is sufficiently thermally insulated to produce excellent uniformity and stability, leading to high quality freeze-initiation and minimal thermal influences on the freezing point. By employing the improved furnace and newly-fabricated tin fixed-point cells, the start and end of the melting plateau and the end of the freezing plateau were accurately determined, enabling reliable evaluation of the liquid fraction during the realization of the tin fixed-point compared to conventional methods. Two open-type tin fixed-point cells were fabricated using high-purity tin that was chemically analyzed for impurity content. Thermal analysis results of freezing-point depression are compared to those based on the chemical analysis.

Yamazawa, K.; Widiatmo, J. V.; Arai, M.

2007-12-01

152

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  

NASA Astrophysics Data System (ADS)

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).

Pokhodun, A. I.

2010-01-01

153

Hydrocarbon exclusion from ground water during freezing  

SciTech Connect

Bench-scale studies were conducted using a constant-head ground-water flow chamber and natural soil. Initial experiments with chlorides and dye were conducted to test the hydraulic and adsorptive characteristics of the chamber. A constant flow of phenol was then introduced into the chamber and contaminant movement with time was monitored under freezing and nonfreezing conditions. The chamber was located in a controlled-temperature room, and freezing fronts were induced from the soil surface downward using cooled Freon circulated through freezer pads placed on the surface of the soil. The results conclusively demonstrate that phenol is excluded from the freezing front and pushed downward through the system. Extensive exclusion of the chemical occurs even though the freezing point of phenol (43 C) is significantly higher than water. The information gained through this research is applicable in cold regions outside Alaska and the Arctic where ground water systems may undergo periodic freezing, and may also be of extreme importance in artificial-freezing scenarios such as those currently being investigated by the Environmental Protection Agency (EPA) as a method of contaminant containment.

Tumeo, M.A.; Davidson, B. (Univ. of Alaska, Fairbanks (United States))

1993-08-01

154

Ponds Freeze in Winter -- Why Doesn't the Ocean?  

NSDL National Science Digital Library

In this activity, learners explore how salt water freezes in comparison to fresh water. Use this experiment to consider how pond animals survive cold winters in comparison to animals that live in the ocean. This resource includes information about freezing points as well as examples of how different animals respond to the winter cold.

Aquarium, New E.

2011-01-01

155

Analysis of stresses during the freezing of solid spherical foods  

Microsoft Academic Search

An analytical model is presented to calculate thermal stresses and strains during the freezing of a spherical food, taking into account both the expansion during phase change and subsequent thermal contraction due to temperature decrease. The Young modulus and Poisson ratio are assumed to undergo a step change at the freezing point. The expansion due to phase change cause a

Q. Tuan Pham; Alain Le Bail; Brice Tremeac

2006-01-01

156

Two-dimensional freezing criteria for crystallizing colloidal monolayers  

SciTech Connect

Video microscopy was employed to explore crystallization of colloidal monolayers composed of diameter-tunable microgel spheres. Two-dimensional (2D) colloidal liquids were frozen homogenously into polycrystalline solids, and four 2D criteria for freezing were experimentally tested in thermal systems for the first time: the Hansen-Verlet freezing rule, the Loewen-Palberg-Simon dynamical freezing criterion, and two other rules based, respectively, on the split shoulder of the radial distribution function and on the distribution of the shape factor of Voronoi polygons. Importantly, these freezing criteria, usually applied in the context of single crystals, were demonstrated to apply to the formation of polycrystalline solids. At the freezing point, we also observed a peak in the fluctuations of the orientational order parameter and a percolation transition associated with caged particles. Speculation about these percolated clusters of caged particles casts light on solidification mechanisms and dynamic heterogeneity in freezing.

Wang Ziren; Han Yilong [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay (Hong Kong); Alsayed, Ahmed M. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd St., Philadelphia, Pennsylvania 19104 (United States); Complex Assemblies of Soft Matter, CNRS/UPENN/Rhodia UMI 3254, Bristol, Pennsylvania 19007 (United States); Yodh, Arjun G. [Department of Physics and Astronomy, University of Pennsylvania, 209 South 33rd St., Philadelphia, Pennsylvania 19104 (United States)

2010-04-21

157

Study on the Realization of Zinc Point and the Zinc-Point Cell Comparison  

NASA Astrophysics Data System (ADS)

Continuing our study on aluminum, tin, and silver points, a study on the realization of the zinc point was conducted. Zinc-point cells were newly fabricated using 6N-nominal grade zinc samples, impurity elements of which were analyzed extensively based on glow-discharge mass spectrometry (GDMS). The present paper reports the temperature measurements done using the newly fabricated cells during the zinc freezing process, under which the zinc fixed point is defined, and the analysis of the freezing curve obtained. Comparisons of zinc-point temperatures realized by the newly fabricated cells (cell-to-cell comparisons) were also conducted. Zinc-point depression due to impurity elements was calculated based on the sum of individual estimates and the impurity element analysis. One of the cells evaluated was drawn out from its crucible and analyzed by GDMS at four points, namely, at around the center of the top, of the middle, of the bottom, and around the outer part of the middle area. The purpose of this cell disassembly is to see whether or not there has been some difference before and after cell fabrication, as well as difference in impurity element distribution within the ingot. From the aforementioned studies, some findings were obtained. First finding is that the homogeneity of the zinc ingot was within 30%, except for Pb, which was more concentrated in the center part. Second finding is that the cell-to-cell temperature difference changes along with the progressing solidification process. As a consequence, for an accurate cell-to-cell comparison, the locus in the freezing plateau where the comparison is done should be determined. Third finding is that the slope analysis estimates accurately the cell-to-cell comparison, and is consistent with the impurity analysis. This shows that the slope analysis gives extensive information about the effect of impurity to the zinc-point realization, especially after the cell fabrication.

Widiatmo, J. V.; Sakai, M.; Satou, K.; Yamazawa, K.; Tamba, J.; Arai, M.

2010-11-01

158

Study on the Realization of Zinc Point and the Zinc-Point Cell Comparison  

NASA Astrophysics Data System (ADS)

Continuing our study on aluminum, tin, and silver points, a study on the realization of the zinc point was conducted. Zinc-point cells were newly fabricated using 6N-nominal grade zinc samples, impurity elements of which were analyzed extensively based on glow-discharge mass spectrometry (GDMS). The present paper reports the temperature measurements done using the newly fabricated cells during the zinc freezing process, under which the zinc fixed point is defined, and the analysis of the freezing curve obtained. Comparisons of zinc-point temperatures realized by the newly fabricated cells (cell-to-cell comparisons) were also conducted. Zinc-point depression due to impurity elements was calculated based on the sum of individual estimates and the impurity element analysis. One of the cells evaluated was drawn out from its crucible and analyzed by GDMS at four points, namely, at around the center of the top, of the middle, of the bottom, and around the outer part of the middle area. The purpose of this cell disassembly is to see whether or not there has been some difference before and after cell fabrication, as well as difference in impurity element distribution within the ingot. From the aforementioned studies, some findings were obtained. First finding is that the homogeneity of the zinc ingot was within 30%, except for Pb, which was more concentrated in the center part. Second finding is that the cell-to-cell temperature difference changes along with the progressing solidification process. As a consequence, for an accurate cell-to-cell comparison, the locus in the freezing plateau where the comparison is done should be determined. Third finding is that the slope analysis estimates accurately the cell-to-cell comparison, and is consistent with the impurity analysis. This shows that the slope analysis gives extensive information about the effect of impurity to the zinc-point realization, especially after the cell fabrication.

Widiatmo, J. V.; Sakai, M.; Satou, K.; Yamazawa, K.; Tamba, J.; Arai, M.

2011-01-01

159

Two features at the two-dimensional freezing transitions.  

PubMed

We studied the two-dimensional freezing transitions in monolayers of microgel colloidal spheres with short-ranged repulsions in video-microscopy experiments, and monolayers of hard disks, and Yukawa particles in simulations. These systems share two common features at the freezing points: (1) the bimodal distribution profile of the local orientational order parameter; (2) the two-body excess entropy, s(2), reaches -4.5±0.5?k(B). Both features are robust and sensitive to the freezing points, so that they can potentially serve as empirical freezing criteria in two dimensions. Compared with the conventional freezing criteria, the first feature has no finite-size ambiguities and can be resolved adequately with much less statistics; and the second feature can be directly measured in macroscopic experiments without the need for microscopic information. PMID:21261367

Wang, Ziren; Qi, Weikai; Peng, Yi; Alsayed, Ahmed M; Chen, Yong; Tong, Penger; Han, Yilong

2011-01-21

160

A similar law may govern water freezing in minerals and living organisms  

Microsoft Academic Search

THERE is an interesting similarity between the freezing of water in minerals and in biological tissues. Mazur1,2 observed that many living organisms lose viability at threshold temperatures near -10 °C. After investigating this phenomenon from the point of view of possible mechanisms by which living cells suffer damage on freezing, he concluded that a key step in the freezing process

Amos Banin; Duwayne M. Anderson

1975-01-01

161

Freezing and melting water in lamellar structures.  

PubMed

The manner in which ice forms in lamellar suspensions of dielaidoylphosphatidylethanolamine, dielaidoylphosphatidylcholine, and dioleoylphosphatidylcholine in water depends strongly on the water fraction. For weight fractions between 15 and 9%, the freezing and melting temperatures are significantly depressed below 0 degree C. The ice exhibits a continuous melting transition spanning as much as 20 degrees C. When the water weight fraction is below 9%, ice never forms at temperatures as low as -40 degrees C. We show that when water contained in a lamellar lipid suspension freezes, the ice is not found between the bilayers; it exists as pools of crystalline ice in equilibrium with the bound water associated with the polar lipid headgroups. We have used this effect, together with the known chemical potential of ice, to measure hydration forces between lipid bilayers. We find exponentially decaying hydration repulsion when the bilayers are less than about 7 A apart. For larger separations, we find significant deviations from single exponential decay. PMID:7948683

Gleeson, J T; Erramilli, S; Gruner, S M

1994-08-01

162

Ultrasound-Assisted Freezing  

NASA Astrophysics Data System (ADS)

Freezing is a well-known preservation method widely used in the food industry. The advantages of freezing are to a certain degree counterbalanced by the risk of damage caused by the formation and size of ice crystals. Over recent years new approaches have been developed to improve and control the crystallization process, and among these approaches sonocrystallization has proved to be very useful, since it can enhance both the nucleation rate and the crystal growth rate. Although ultrasound has been successfully used for many years in the evaluation of various aspects of foods and in medical applications, the use of power ultrasound to directly improve processes and products is less popular in food manufacturing. Foodstuffs are very complex materials, and research is needed in order to define the specific sound parameters that aid the freezing process and that can later be used for the scale-up and production of commercial frozen food products.

Delgado, A. E.; Sun, Da-Wen

163

Bk060042 Cell Freeze Liquid Nitrogen Freezing Container  

Center for Biologics Evaluation and Research (CBER)

Text Version... NC 21103 Telephone 336 168-6447 F;Jcsirnile 336 774-1150 510(k) Summary Charter Medical Cell Freeze™ Liquid Nitrogen Freezing Container ... More results from www.fda.gov/downloads/biologicsbloodvaccines/bloodbloodproducts

164

CryoMACS Freezing Bag  

Center for Biologics Evaluation and Research (CBER)

... CryoMACS Freezing Bag. Applicant: Miltenyi Biotec, Incorporated. 510(k) number: BK090020. Product: CryoMACS Freezing Bag. ... More results from www.fda.gov/biologicsbloodvaccines/bloodbloodproducts/approvedproducts

165

Modeling soil freezing dynamics  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seasonally frozen soil strongly influences runoff and erosion on large areas of land around the world. In many areas, rain or snowmelt on seasonally frozen soil is the single leading cause of severe runoff and erosion events. As soils freeze, ice blocks the soil pores, greatly diminishing the permea...

166

Animal Anti-Freeze  

NSDL National Science Digital Library

In this outdoor winter activity, learners search for and create hibernation sites that will protect gelatin "animals" from freezing. Learners come to understand that hibernating animals need to take care in selecting a sleeping spot that will provide protection from the winter cold.

Science, Lawrence H.

1982-01-01

167

Freezing human ES cells.  

PubMed

Here we demonstrate how our lab freezes HuES human embryonic stem cell lines. A healthy, exponentially expanding culture is washed with PBS to remove residual media that could otherwise quench the Trypsin reaction. Warmed 0.05% Trypsin-EDTA is then added to cover the cells, and the plate allowed to incubate for up to 5 mins at room temperature. During this time cells can be observed rounding, and colonies lifting off the plate surface. Gentle repeated pipetting will remove cells and colonies from the plate surface. Trypsinized cells are placed in a standard conical tube containing pre-warmed hES cell media to quench remaining trypsin, and then spun. Cells are resuspended growth media at a concentration of approximately one million cells in one mL of media, a concentration such that one frozen aliquot is sufficient to resurrect a culture on a 10 cm plate. After cells are adequately resuspended, ice cold freezing media is added at equal volume. Cell suspensions are mixed thoroughly, aliquoted into freezing vials, and allowed to slowly freeze to -80 C over 24 hours. Frozen cells can then moved to the vapor phase of liquid nitrogen for long term storage, or remain at -80 for approximately six months. PMID:18704182

Trish, Erin; Dimos, John; Eggan, Kevin

2006-10-12

168

Freezing Potential of Electrolytic Solutions  

Microsoft Academic Search

The freezing potential for NH3 and NaCl solutions is studied with the experiments being performed at approximately constant freezing rates. The results permit discussion of the transitory and stationary features of the phenomenon. For NH4 solutions, the stationary freezing potential is studied as a function of the growth rate and of the concentration of the solutions. Measurements were also made

Laura Levi; Oscar Milman

1966-01-01

169

Comp aratrve Ultrastructure of Fat Body Cells of Freeze-susceptible and Freeze-tolerant Eurosta solidaginis Larvae After Chemical Fixation and High Pressure Freezing  

Microsoft Academic Search

Cold-hard- ening includes the elevation of the supercooling point, the temperature at which body water spontaneously freezes, and the accumulation of the low-molecular-mass cryoprotectants, glycerol, sorbitol and trehalose. Although it is generally believed that freezing survival is only possible if the ice lattice is restricted to the extracellular space, the larval fat body cells survive intracellular ice formation. Fat body

R. TODD MORASON; ALLAN L. ALLENSPACH; RICHARD E. LEE JR

170

Depression - resources  

MedlinePLUS

Resources - depression ... Depression is a medical condition. If you think you may be depressed, see a health care provider. ... following organizations are good resources of information on depression : American Psychological Association - www.apa.org/topics/depress/ ...

171

Freezing avoidance of the Antarctic icefishes (Channichthyidae) across thermal gradients in the Southern Ocean  

Microsoft Academic Search

Biogeographic studies separate the Antarctic Notothenioid fish fauna into high- and low-latitude species. Past studies indicate\\u000a that some species found in the high-latitude freezing waters of the High-Antarctic Zone have low-serum hysteresis freezing\\u000a points, while other species restricted to the low-latitude seasonal pack ice zone have higher serum hysteresis freezing points\\u000a above the freezing point of seawater (?1.9°C), but the

Kevin T. Bilyk; Arthur L. DeVries

2010-01-01

172

Critical freezing rate in freeze drying nanocrystal dispersions.  

PubMed

Recent advances in nanoparticle technologies have significantly enhanced the oral and parenteral delivery of poorly water-soluble active pharmaceutical ingredients (APIs). However, reports have been limited on the various drying procedures to convert a liquid nanocrystal dispersions into solid dosage forms. The solid dosage form should consist of nanocrystals that can readily reconstitute into their original size upon dissolution in water. Herein, the freeze drying process of nanocrystal dispersions was examined at varying freezing rates (speed of freezing interface). As freezing rate decreases, more particle-particle aggregation developed. A critical freezing rate, below which the dried nanocrystals cannot be re-dispersed, was identified based on the plot of the particle size of reconstituted nanocrystals versus freezing rate. Freeze drying at a freezing rate near the critical value produces dry powders of bimodal particle size distribution after re-dispersion. In addition, API concentration was found to significantly affect the critical freezing rate and therefore the re-dispersibility of dry powders. The concept of critical freezing rate is critical for the development of solid dosage forms of liquid nanocrystal dispersions. PMID:16430987

Lee, Jonghwi; Cheng, Yu

2006-01-23

173

Mechanisms of freezing damage.  

PubMed

Freezing of aqueous systems involves numerous simultaneous changes but this review concentrates on direct effects of the formation of ice and the consequent concentration of solutes in the remaining liquid phase. It is generally believed that cell injury at low cooling rates is principally due to the concentration of both intracellular and extracellular electrolytes and that cryoprotectants act by reducing this build-up. New experimental data are presented to support this explanation; we find that the extent of damage to human red blood cells during freezing in solutions of sodium chloride/glycerol/water can be quantitatively accounted for by the increase in solute concentration. However, we also show that a given degree of damage occurs at lower concentrations of solute in the presence of higher concentrations of glycerol; it appears that glycerol contributes an element of damage itself. Recently published studies from Mazur's laboratory have suggested that the dominant damaging factor at low cooling rates is actually the reduction of the quantity of unfrozen water rather than the corresponding increase in salt concentration that accompanies freezing. These data are re-evaluated, and it is argued that the experimental results could equally well be explained by a susceptibility of cells to shrinkage and re-expansion as the concentration of external impermeant solutes first increases during freezing and then decreases during thawing. It is concluded that external ice probably has no directly damaging effect upon dilute suspensions of cells. However, it is also argued that ice is directly damaging whenever it forms intracellularly, and also when it forms extracellularly in densely packed cell suspensions. In the latter case the damage is probably due to recrystallization of the ice masses during thawing. Extracellular ice also has a directly damaging effect when tissues and organs are frozen. The difficulties of designing experimental methods that will yield unequivocal results is emphasized, and consequently the above conclusions must be regarded as tentative at the present time. PMID:3332492

Pegg, D E

1987-01-01

174

Winter Depression  

NSDL National Science Digital Library

A U.K. psychologist has developed a complex mathematical formula using seven variables to predict winter's emotional low point. The good news is the worst day of the year was last week; nonetheless, seasonal depression remains a problem for many. The first link (1) is to an article about the equation worked out by Dr. Cliff Arnall, who specializes in seasonal disorders at the University of Cardiff, Wales. The second link is to a WebMD page (2) about winter depression, often referred to as Seasonal Affective Disorder (SAD). The next link (3) is to a recent news story about the results of a five-year study that found, rather than antidepressant drug therapy or air ionizers, light box therapy is the best remedy for the seasonal condition. The fourth link is to a set of Frequently Asked Questions (4) about SAD offered by Columbia Presbyterian Medical Center in New York City. The fifth link, to the Winter Depression Research Group at the University of Tromso in Norway(5), explains why Norway is a natural SAD research laboratory. The next link is to a international portal site (6) maintained by medical professionals and researchers in the field of light therapy and biological rhythms. The final webpage(7), from Psychology Today, compares the symptoms of winter depression with summer depression.

175

Later-life depression and heart failure.  

PubMed

Using a case history to illustrate key points, this article (1) highlights depression criteria, prevalence, and later-life depression presentations; (2) discusses factors contributing to later-life depression; (3) reviews the interplay between heart failure and later-life depression; and (4) suggests screening and treatment recommendations for depression in patients with heart failure. PMID:21109207

Maixner, Susan M; Struble, Laura; Blazek, Mary; Kales, Helen C

2011-01-01

176

Competitive freezing in gold nanoparticles  

NASA Astrophysics Data System (ADS)

We use molecular dynamics simulations to study the freezing of gold nanoparticles in a size range of N = 309-923 gold atoms and find the clusters freeze to a variety of structures, including icosahedra, decahedra and face-centered cubic type structures. Measurements of the rate of freezing for the different structures reveal that the icosahedral clusters form an order ofmagnitude faster than the remaining structures over the entire range of cluster sizes studied. An analysis of the structural evolution of the icosahedral and decahedral clusters during freezing events suggests that, despite the vast difference in freezing rates, the two structures both initially form the same five-fold symmetric cap, constructed from tetrahedral sub-units of face-centered cubic packed atoms. The slow rate of decahedron freezing may be caused introduction of strain into the structure as it grows along the five-fold symmetric axis of the cluster and the need to form high energy <100> facets.

Asuquo, Cletus C.; Bowles, Richard K.

2013-05-01

177

Magnetic freezing of confined water  

NASA Astrophysics Data System (ADS)

We report results from molecular dynamic simulations of the freezing transition of liquid water in the nanoscale hydrophobic confinement under the influence of a homogeneous external magnetic field of 10 T along the direction perpendicular to the parallel plates. A new phase of bilayer crystalline ice is obtained at an anomalously high freezing temperature of 340 K. The water-to-ice translation is found to be first order. The bilayer ice is built from alternating rows of hexagonal rings and rhombic rings parallel to the confining plates, with a large distortion of the hydrogen bonds. We also investigate the temperature shifts of the freezing transition due to the magnetic field. The freezing temperature, below which the freezing of confined water occurs, shifts to a higher value as the magnetic field enhances. Furthermore, the temperature of the freezing transition of confined water is proportional to the denary logarithm of the external magnetic field.

Zhang, Guangyu; Zhang, Weiwei; Dong, Huijuan

2010-10-01

178

Magnetic freezing of confined water.  

PubMed

We report results from molecular dynamic simulations of the freezing transition of liquid water in the nanoscale hydrophobic confinement under the influence of a homogeneous external magnetic field of 10 T along the direction perpendicular to the parallel plates. A new phase of bilayer crystalline ice is obtained at an anomalously high freezing temperature of 340 K. The water-to-ice translation is found to be first order. The bilayer ice is built from alternating rows of hexagonal rings and rhombic rings parallel to the confining plates, with a large distortion of the hydrogen bonds. We also investigate the temperature shifts of the freezing transition due to the magnetic field. The freezing temperature, below which the freezing of confined water occurs, shifts to a higher value as the magnetic field enhances. Furthermore, the temperature of the freezing transition of confined water is proportional to the denary logarithm of the external magnetic field. PMID:20942551

Zhang, Guangyu; Zhang, Weiwei; Dong, Huijuan

2010-10-01

179

How low-permeability rocks freeze: A laboratory study on resistivity pathways of thawed, supercooled and frozen permafrost rocks  

NASA Astrophysics Data System (ADS)

Resistivity - temperature paths are among the most important proxies in permafrost research. Testing 8 sedimentary, metamorphic and igneous rocks from European permafrost summits, we found evidence that the theoretical background developed in the 70s does not describe the physics of low-permability rocks correctly, which dominate these environments. Saturated rocks with permeabilities below 10 µD have an equilibrium freezing point depression of -0.5°C to -1.55°C and indicate metastable supercooling effects between -0.5 and -1.4 °C. Instantaneous freezing from metastable stages occurs with sudden warming of the rock sample with up to 0.9°C temperature difference. This is due to the spontaneous dissipation of freezing energy subsequent to supercooling. Warming occurs over tens of seconds to a few minutes and coincides with a jump in resistivity. Unfrozen and frozen temperature-resistivity paths match bilinear functions with an R² of 0.88 to 1.00. The frozen temperature-resistivity gradient is 12-34 times steeper that the unfrozen resistivity gradient. Low permeability may decide the ratio of frozen and unfrozen gradients while porosity influences the 0°C resistivity value and the unfrozen gradient. Here we show that separate linear approximation of unfrozen, supercooled and frozen temperature-resistivity behaviour provides a better explanation of involved physics than exponential fits.

Krautblatter, M.; Zisser, N.

2009-04-01

180

Organic Solutes in Freezing Tolerance  

Microsoft Academic Search

The accumulation of high levels of low-molecular-weight solutes (polyhydric alcohols, saccharides) provides cryoprotection to freeze-tolerant animals by minimizing, via colligative effects, the percentage of body water converted to extracellular ice and the extent of cell volume reduction. Many freeze-tolerant insects accumulate high levels of polyols during autumn cold hardening, whereas freeze-tolerant frogs respond to ice formation in peripheral tissues by

Kenneth B. Storey

1997-01-01

181

A NEW FREEZING-ULTRAMICROTOME  

Microsoft Academic Search

The difficulties in sectioning frozen biological objects for electron microscopic investigations are overcome by Steere's freezing-etching method. In order to test this method and to open up a wide field of application, the new freezing-ultramicrotome has been designed. The apparatus consists of the combination of an ultramicrotome with freezing-drying and shadow-casting installations in the same vacuum container. The preliminary results

H. Moor; K. MtSHLETHALER; H. WALDNER; A. FREY-WYSSLING

1961-01-01

182

Thermal properties of ration components as affected by moisture content and water activity during freezing.  

PubMed

Beef roast with vegetables is an example of a meal, ready-to-eat (MRE) ration entrée. It is a mixture of meat, potato, mushroom, and carrot with a gravy sauce. The thermal properties of each component were characterized in terms of freezing point, latent heat, freezable and unfreezable water contents, and enthalpy during freezing using differential scanning calorimetry. Freezing and thawing curves and the effect of freezing and thawing cycles on thermal properties were also evaluated. The freezing points of beef, potato, mushroom, and sauce were all in the range of -5.1 to -5.6 degrees C, but moisture content, water activity, latent heat, freezable and unfreezable water contents, and enthalpy varied among these components. Freezing temperature greatly affected the unfrozen water fraction. The unfreezable water content (unfrozen water fraction at -50 degrees C) of ration components was in the range of 8.2% to 9.7%. The freezing and thawing curves of vegetables with sauce differed from those of beef but took similar time to freeze or thaw. Freezing and thawing cycles did not greatly affect the thermal properties of each component. Freezing point and latent heat were reduced by decreasing moisture content and water activity of each component. Water activity was proportionally linear to freezing point at a(w) > 0.88, and moisture content was proportionally linear to freezable water content in all ration components. Water was not available for freezing when moisture content was reduced to 28.8% or less. This study indicates that moisture content and water activity are critical factors affecting thermal behavior of ration components during freezing. PMID:19021797

Li, J; Chinachoti, P; Wang, D; Hallberg, L M; Sun, X S

2008-11-01

183

Freezing of Nonwoody Plant Tissue  

PubMed Central

Temperature recordings of the freezing of plant tissues include two plateaus or regions of reduced slope. During the second of these, small positive spikes were observed. When a completely frozen tissue was thawed and refrozen, neither the second plateau nor the spikes were recorded. Both were present, however, if the initial freezing had been terminated before the second plateau had been reached. The spikes appear to represent the release of heat of crystallization during the freezing of individual cells. Such a freezing and thawing cycle destroys the ability of the cells to remain supercooled in the presence of the ice that is formed as the first plateau is recorded.

Brown, M. S.; Pereira, E. Sa B.; Finkle, Bernard J.

1974-01-01

184

Local structure, fluctuations, and freezing in two dimensions  

NASA Astrophysics Data System (ADS)

Starting from the concept of local solidlike order in two-dimensional (2D) liquids we introduce and quantify the corresponding ensembles of fluctuations, using a probabilistic-based method of local-structure analysis (LSA). A systematic LSA (including size dependence) was performed for a hard disk and 2D Lennard-Jones systems, simulated using Monte Carlo and molecular-dynamics methods. We find that the onset of freezing is accompanied by a dramatic crossover between ensembles of fluctuations. Some universal features related to the onset of freezing in two dimensions are found and corresponding freezing criteria are formulated: (i) the liquid starts to freeze when the concentration of solidlike atoms constitutes 0.50-0.56, and (ii) a Lindemann-like freezing criterion: the rms fluctuation constitutes, at the onset, 0.12-0.13. Those criteria offer an effective method for a localization of the onset of freezing in computer simulations. We point out, in this context, that in computer simulations there is a possibility that all quantitative characterizations of the onset of freezing are related to a metastable range. This important methodological topic is discussed briefly in the light of recent results both for 2D and 3D systems.

Mitus, A. C.; Patashinski, A. Z.; Patrykiejew, A.; Sokolowski, S.

2002-11-01

185

Major depression  

MedlinePLUS

Depression - major; Unipolar depression; Major depressive disorder ... The exact cause of depression is not known. Many researchers believe it is caused by chemical changes in the brain. This may be due to ...

186

Combined impacts of freeze-thaw processes on paddy land and dry land in Northeast China.  

PubMed

The quantity of spring snowmelt infiltration and runoff, which affects the hydrology of the freeze zone, depends on the antecedent soil water content (SWC) conditions at the time of the soil's freezing. An understanding of the characteristics of frozen soil is essential for spring sowing in the agricultural freeze zones. The main goal of this study was to evaluate the differences in the freeze-thaw process and the freeze-thaw-induced water redistribution between the paddy and dry lands in a freeze zone. For this purpose, a field study was conducted in the winter of 2011-2012 for two types of farmlands in Northeast China. To illustrate the soil's frost dynamics over time, the measured SWCs at different depths (15, 30, 60, and 90 cm) were transformed into different expressions including the SWC dynamic, the frozen soil's profile, and the freezing and thawing front trace. The freezing characteristics in the paddy land, in contrast to that in the dry land, had a higher freezing point temperature, a larger amount of water movement to the upper layer, and a 2.76 mm larger accumulation of water in the upper layer. However, the increase of SWC (which is equivalent to thawing) was evidently faster than the decrease of SWC (which is equivalent to freezing). The water in the frozen soil's profile was most likely redistributed towards the freezing front before soil temperature (ST) falls below the freezing point. The findings may partially explain the soil's freeze-thaw characteristics for the different stages as well as the combined impact of these characteristics with farmland use types on soil hydrology; the findings may also provide a foundation for forecasting the hydrologic response of the freeze-thaw process and provide guidance for management strategies dealing with seasonally frozen agricultural soils. PMID:23584030

Chen, Siyang; Ouyang, Wei; Hao, Fanghua; Zhao, Xuchen

2013-04-10

187

Infrared spectroscopy of sulfuric acid/water aerosols: Freezing characteristics  

NASA Astrophysics Data System (ADS)

A low-temperature flow cell has been used in conjunction with a Fourier transform infrared (FT-IR) spectrometer to study sulfuric acid/water aerosols. The aerosols were generated with a wide range of composition (28 to 85 wt%), including those characteristic of stratospheric sulfate aerosols, and studied over the temperature range from 240 K to 160 K. The particles exhibited deep supercooling, by as much as 100 K below the freezing point in some cases. Freezing of water ice was observed in the more dilute (<40 wt% sulfuric acid) particles, in agreement with the predictions of Jensen et al. and recent observations by Bertram et al. In contrast with theoretical predictions, however, the entire particle often does not immediately freeze, at least on the timescale of the present experiments (seconds to minutes). Freezing of the entire particle is observed at lower temperatures, well below that characteristic of the polar stratosphere.

Clapp, M. L.; Niedziela, R. F.; Richwine, L. J.; Dransfield, T.; Miller, R. E.; Worsnop, D. R.

1997-04-01

188

Freezing in a vertical tube  

Microsoft Academic Search

Fundamental heat transfer experiments were performed for freezing of an initially superheated or nonsuperheated liquid in a cooled vertical tube. Measurements were made which yielded information about the freezing front and the frozen mass, about the various energy components extracted from the tube, and about the decay of the initial liquid superheat. Four component energies were identified and evaluated from

E. M. Sparrow; J. A. Broadbent

1983-01-01

189

Freezing controlled by natural convection  

Microsoft Academic Search

Experiments were performed for freezing under conditions where the liquid phase is either above or at the fusion temperature (i.e., superheated or nonsuperheated liquid). The liquid was housed in a cylindrical containment vessel whose surface was maintained at a uniform, time-invariant temperature during a data run, and the freezing occurred on a cooled vertical tube positioned along the axis of

E. M. Sparrow; J. W. Ramsey; R. G. Kemink

1979-01-01

190

Letter: freezing theory of rbcl  

Microsoft Academic Search

A criterion for freezing of alkali halides in terms of the principal peak of the liquid charge-charge structure factor SQQ(k) has been given in earlier work. Subsequently, a theory of freezing of both neutral binary alloys and alkali halides has been developed, based on partial liquid structure factors as input information.

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

1982-01-01

191

Late-life Depression  

Microsoft Academic Search

In the article “best treatment” of late-life depression is discussed and an alternative way of thinking in regard to psychotherapeutical intervention is suggested. It is concluded that late-life depression is a field demanding a differentiated psychotherapeutic and rehabilitation oriented working model by the psychotherapist, and old age is treated here from a developmental point of view. It is also concluded

Karen Munk

2007-01-01

192

Thermal Freeze-out Versus Chemical Freeze-out Reexamined  

NASA Astrophysics Data System (ADS)

An alternative, to the commonly used blast-wave, model describing the freeze-out hypersurface is applied to fit the pT-spectra of identified hadrons measured at relativistic heavy-ion collisions at sqrt sNN = 62.4, 130 and 200 GeV. Decays of resonances are taken into account completely. It has turned out that the fitted freeze-out temperature and baryon number chemical potential depend weakly on the centrality of the collision and their values are close to the chemical freeze-out values determined from fits to particle yield ratios.

Prorok, D.

2009-10-01

193

Biomimetic Materials by Freeze Casting  

NASA Astrophysics Data System (ADS)

Natural materials, such as bone and abalone nacre, exhibit exceptional mechanical properties, a product of their intricate microstructural organization. Freeze casting is a relatively simple, inexpensive, and adaptable materials processing method to form porous ceramic scaffolds with controllable microstructural features. After infiltration of a second polymeric phase, hybrid ceramic-polymer composites can be fabricated that closely resemble the architecture and mechanical performance of natural bone and nacre. Inspired by the narwhal tusk, magnetic fields applied during freeze casting can be used to further control architectural alignment, resulting in freeze-cast materials with enhanced mechanical properties.

Porter, Michael M.; Mckittrick, Joanna; Meyers, Marc A.

2013-06-01

194

Ethical aspects of social freezing.  

PubMed

The term "social freezing" is used to degrade the reason for freezing eggs to the level of a wish instead of a need. The main problem is that the distinction between "social" and "medical" freezing is very difficult to make and many applications do not fit nicely into one of the categories. The rejection of these applications also suffers from a number of inconsistencies. Given the difficulties in separating the two models, it is proposed that all applications, regardless of the reason, should be evaluated with the same criteria: efficiency, safety and justice. PMID:23972914

Pennings, G

2013-08-21

195

FREEZE-THAWING EFFECTS ON PHOSPHORUS LOSS IN RUNOFF FROM MANURED AND CATCH-CROPPED SOILS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Concern over non-point source phosphorus (P) losses from agricultural lands to surface waters in frigid climates has focused interest on the effects of freezing and thawing on P loss in overland and subsurface flow. This study evaluated the effect of freezing and thawing on the fate of P in bare soi...

196

Freezing of supercooled water nanodroplets  

NASA Astrophysics Data System (ADS)

All three states of water play important roles in nature, from thermostating the atmosphere to providing reactive surfaces environments. The rates at which transitions between the phases occur, the degree to which pure liquid water can be supercooled, and the solid phases that form are all fundamentally interesting questions with strong atmospheric relevance. We have followed and characterized the nucleation, growth, and subsequent freezing of pure water droplets formed in a supersonic nozzle apparatus using both Small Angle X-ray Scattering (SAXS) and Fourier Transform Infrared Spectroscopy (FTIR). Because the droplets have radii r between 3 nm and 6 nm, and the cooling rates are on the order of 5E5 K/s, liquid water only begins to freeze below approximately 215 K. These temperatures are well below the homogeneous freezing limit for bulk water. The experiments show the expected decrease in freezing temperature with decreasing droplet size, or alternatively, with increasing droplet internal pressure.

Wyslouzil, Barbara

2013-03-01

197

Thermal analysis on the realization of the tin fixed point  

NASA Astrophysics Data System (ADS)

A study on the thermal analysis of a new tin fixed-point open cell within a new three-zone furnace was carried out. The stability at the setting temperatures of liquid-solid coexisting together with some degree Celsius lower and higher than the tin fixed point; and the axial uniformity of furnace while tin is still in solid phase were investigated and analyzed. The impurities effect on the depression in temperature was investigated in terms of ?T (Tobserved-T1/F=0) and the inverse of the melted fraction (1/F) relationship during the melting and the following freezing realizations at various temperature settings of furnace. These thermal analysis results were also compared with those estimated by the CCT-WG1 recommended SIE (sum of individual estimates) method, which leads to a temperature correction along with a corresponding uncertainty through the individual impurity content detected by GDMS (glow discharge mass spectrometry).

Tsai, S. F.

2013-09-01

198

Cryoprotective and osmotic responses to cold acclimation and freezing in freeze-tolerant and freeze-intolerant earthworms  

Microsoft Academic Search

In this paper we present the results of physiological responses to winter acclimation and tissue freezing in a freeze-tolerant\\u000a Siberian earthworm, Eisenia nordenskioeldi, and two freeze-intolerant, temperate earthworm species, Lumbricus rubellus and Aporrectodea caliginosa. By analysing the physiological responses to freezing of both types we sought to identify some key factors promoting freeze\\u000a tolerance in earthworms. Winter acclimation was followed

M. Holmstrup; J. P. Costanzo; R. E. Lee Jr

1999-01-01

199

Passive freeze protection for solar collectors  

Microsoft Academic Search

Freeze damage is an important practical problem for water-type solar collectors. This note describes a simple passive concept that can be used to protect water-type solar collectors from freeze damage. Briefly, the water is allowed to freeze. As it freezes, however, it expands against a compliant region, and thus, the expansion does not damage the system. (auth)

L BICKLE

1975-01-01

200

Freezing behaviour of microencapsulated water.  

PubMed

The freezing behaviour of water in polyurea microcapsules was studied through DSC (differential scanning calorimetry) and ESR (electron spin resonance) measurements under a non-equilibrium condition to show that supercooling of water becomes more noticeable with decreasing droplet size of the liquid. Thermodynamics of small systems was found applicable to analyse the experimental findings, even though the process of water freezing in the microcapsules was not of an equilibrium nature. PMID:1328582

Yamane, H; Ohshima, H; Kondo, T

201

Heritage roundtable: the nuclear freeze  

SciTech Connect

The transcript of a panel of foreign policy experts, chaired by former National Security Adviser Richard Allen, debates the proposed nuclear freeze. They consider whether a freeze is a step in the right direction, acting to slow the arms race and contribute to world security, or whether it would aggravate strategic problems by perpetuating an umbalanced situation. Disagreement among the participants makes clear that no one favors nuclear war, but there are differing perspectives on how to continue preventing such a war.

Allen, R.V.; Gray, C.; Kalicki, J.; Pfaltzgraff, R.; Scoville, H.

1982-01-01

202

Diffusion controlled ice growth with soft impingement inside biological cells during freezing.  

PubMed

An iterative method has been proposed to determine the relationship between the temperature depression of intracellular ice formation (IIF) and the equilibrium melting point depression for initial cryoprotective agent (CPA) concentrations larger than 1.5M. Using the iterative method coupling with a water transport model for freezing induced cell dehydration and intracellular ice growth, the temperature of IIF has been determined. The new model of temperature of IIF has been applied to predict nucleation parameters at various temperature and initial CPA concentrations according to Karlsson's approach. A geometrical model of soft impingement proposed by Bruna has been incorporated into Karlsson's diffusion limited crystal growth model to include the effect of soft impingement. The new crystal growth model has been verified by a comparison between the predicted critical cooling rates for vitrification with the reported values in literature. With the new crystal growth model, it has been found that the limiting value of the crystallized volume fraction increases as cooling progresses and decreases as the initial CPA concentration increases. A comparison of simulated crystallized volume fractions when soft impingement, hard impingement and no corrections are used has also been made and the result shows that soft impingement could not be omitted in the prediction of intracellular ice formation and growth, especially when the final crystallized volume fraction is larger than 0.1. PMID:18946551

Chen, Cong; Li, Weizhong

203

Freeze concentration of fruit juices.  

PubMed

Concentration of aqueous foods such as fruit juices, milk, beer, wine, coffee, and tea, is a major unit operation in the food industry. Technically feasible processes that are commercially available for the concentration of liquid foods include evaporation, freeze concentration, reverse osmosis, and ultrafiltration. Evaporation is considered to be the most economical and most widely used method of concentration. However, it is not suited for food products with very delicate flavors. Commercial processes for the concentration of such products by membrane separation techniques are not yet available. As compared to the conventional evaporation processes, concentration by freezing is potentially a superior and economic process for aroma-rich liquid foods. In the past, the process, however, was seldom used because of the investment cost and the considerable loss of concentrate in the withdrawn ice, and hence, the quality. Recent technological developments have minimized these two drawbacks associated with the earlier freeze concentration processes. In the coming decade, freeze concentration is seen as a potentially attractive method for the concentration of aroma-rich liquid foods, including fruit juices, coffee, tea, and selected alcoholic beverages. In this article, several aspects of the theoretical considerations behind freeze concentration of fruit juices, the development of new and cheaper designs, and commercially available freeze concentration processes are reviewed. The economics of the process and its application to several other areas of the food industry are also discussed. PMID:6383717

Deshpande, S S; Cheryan, M; Sathe, S K; Salunkhe, D K

1984-01-01

204

Postpartum Depression  

MedlinePLUS

... all forms of depression, postpartum depression creates a cloud of negative feelings and thoughts over a woman's ... her, her situation, and the future. Under the cloud of depression, a woman might see herself as ...

205

Caregiver Depression  

MedlinePLUS

... will not sell or share your name. Caregiver Depression Tweet Bookmark this page | Email | Print Many caregivers ... depression See your doctor Treatment Coping Symptoms of depression Caregiving is hard ? and can lead to feelings ...

206

Freezing and ice crystals formed in a cylindrical food model: part I. Freezing at atmospheric pressure  

Microsoft Academic Search

Cylindrical gelatin gels were frozen at atmospheric pressure with different operating conditions (air-blast freezing at different air temperatures and brine freezing). A method to calculate a local freezing rate was proposed to take into account the variation of freezing rate as a function of the radius. A linear evolution of the local freezing rate according to the radius was observed

D Chevalier; A Le Bail; M Ghoul

2000-01-01

207

NUMERICAL BENCHMARK BASED ON NATURAL CONVECTION OF FREEZING WATER  

Microsoft Academic Search

The proposed benchmark configuration concerns steady-state natural convection of water in the differentially heated cube-shaped cavity for temperatures close to the freezing point. Strongly non-linear buoyancy term allowed for thoughtful testing of several numerical approaches. After selecting the best performing one a new, very restrictive verification procedure is proposed. The verified numerical code is used to simulate the \\

Tomasz Michalek; Tomasz A. Kowalewski

208

Synchrotron X-Ray Visualisation of Ice Formation in Insects during Lethal and Non-Lethal Freezing  

PubMed Central

Although the biochemical correlates of freeze tolerance in insects are becoming well-known, the process of ice formation in vivo is subject to speculation. We used synchrotron x-rays to directly visualise real-time ice formation at 3.3 Hz in intact insects. We observed freezing in diapausing 3rd instar larvae of Chymomyza amoena (Diptera: Drosophilidae), which survive freezing if it occurs above ?14°C, and non-diapausing 3rd instar larvae of C. amoena and Drosophila melanogaster (Diptera: Drosophilidae), neither of which survive freezing. Freezing was readily observed in all larvae, and on one occasion the gut was seen to freeze separately from the haemocoel. There were no apparent qualitative differences in ice formation between freeze tolerant and non-freeze tolerant larvae. The time to complete freezing was positively related to temperature of nucleation (supercooling point, SCP), and SCP declined with decreasing body size, although this relationship was less strong in diapausing C. amoena. Nucleation generally occurred at a contact point with the thermocouple or chamber wall in non-diapausing larvae, but at random in diapausing larvae, suggesting that the latter have some control over ice nucleation. There were no apparent differences between freeze tolerant and non-freeze tolerant larvae in tracheal displacement or distension of the body during freezing, although there was markedly more distension in D. melanogaster than in C. amoena regardless of diapause state. We conclude that although control of ice nucleation appears to be important in freeze tolerant individuals, the physical ice formation process itself does not differ among larvae that can and cannot survive freezing. This suggests that a focus on cellular and biochemical mechanisms is appropriate and may reveal the primary adaptations allowing freeze tolerance in insects.

Sinclair, Brent J.; Gibbs, Allen G.; Lee, Wah-Keat; Rajamohan, Arun; Roberts, Stephen P.; Socha, John J.

2009-01-01

209

A Model for Prediction of Shrinkage Defects in Long and Short Freezing Range Materials  

SciTech Connect

The aim of the model presented in this paper is to capture the difference in solidification behaviour of long and short freezing materials. The shrinkage defects in short freezing materials tends to be internal, as porosity, while in long freezing materials these defects tend to be external in the form of surface depressions. To achieve this, a pressure drop based 3-D feeding flow model has been developed to evaluate shrinkage defects for casting alloys. A continuum formulation is used to describe the transport of mass, energy and momentum. It is assumed that during solidification the driving force for flow is shrinkage. A Darcy type source term has been included in the momentum equation to account for flow resistance in the mushy zone. A VOF free surface model has been used to describe shrinkage defects, i.e., external surface depressions and internal shrinkage porosities, while ensuring mass conservation. The model is used to calculate the shrinkage in a simple casting. The results shows internal and outside shrinkage defects depending on the freezing range of the metal. Short freezing range results mainly in internal shrinkage whereas the long freezing range results in external shrinkage. The expected shrinkage features are well described by the present model.

Reis, A.; Duarte, J. F.; Santos, A. D.; Magalhaes, A. B. [FEUP - Faculdade de Engenharia da Universidade do Porto, R.Dr.Roberto Frias s/n, 4200-110 Porto (Portugal); Xu Zhian [WTCM Foundry Center, Research Center of Belgium Metalworking Industry9052 Zwijnaarde, Gent (Belgium); Houbaert, Y. [UGent - University of Ghent, Technologiepark Zwijnaarde 903, Gent (Belgium)

2007-05-17

210

Theoretical analysis of specimen cooling rate during impact freezing and liquid-jet freezing of freeze-etch specimens.  

PubMed Central

We have carried out a theoretical analysis of specimen cooling rate under ideal conditions during impact freezing and liquid-jet freezing. The analysis shows that use of liquid helium instead of liquid nitrogen as cooling medium during impact freezing results in an increase in a specimen cooling rate of no more than 30-40%. We have further shown that when both impact freezing and liquid-jet freezing are conducted at liquid nitrogen temperature, the two methods give approximately the same specimen cooling rate under ideal conditions except for a thin outer layer of the specimen. In this region impact freezing yields the highest cooling rate.

Kopstad, G; Elgsaeter, A

1982-01-01

211

Postpartum depression  

Microsoft Academic Search

Obstetricians must be familiar with the diagnosis and treatment of postpartum depression (PPD), as they are the first contact physicians of most postpartum depressed women. Postpartum depression is particularly critical to treat as it has significant impact on the mother, the infant, and the family if left untreated. Clinicians should be able to identify the risk factors for depression in

Yesne Alici-Evcimen; Donna M. Sudak

2003-01-01

212

FROZEN SAVINGS AND DEPRESSED DEVELOPMENT IN ARGENTINA  

Microsoft Academic Search

Argentina's Convertibility Plan for stabilization and growth fell by fronzen savings on U.S. dollars banking deposits, after three years of economic depression triggered by exchange rate overvaluation, with policy making credibility severely hit by frequent changes in political and institutional scenarios. Banking savings freeze (\\

Francesco Bortot

2003-01-01

213

Freeze-dried microarterial allografts  

SciTech Connect

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.

Raman, J.; Hargrave, J.C.

1990-02-01

214

Artifacts associated with quick-freezing and freeze-drying.  

PubMed

We have studied the structures produced when nonbiological samples were subjected to quick-freezing and freeze-drying with a liquid helium cooled freeze-slamming device. Samples examined in this way included sodium chloride, sucrose, and Tris buffer. A variety of filamentlike and trabeculumlike structures were formed in these preparations. These structures may represent eutectic mixtures formed during the growth of small ice crystals during the freezing process, and exposed during the rapid sublimation of pure ice during the etching process. Samples of biological membranes (isolated chloroplast membranes) were prepared in various buffers by means of this technique. In distilled water, excellent replicas of membrane surfaces were obtained. In salt solutions, however, the membranes appeared to be embedded in a network of thin filaments appearing very much like a cytoskeletal lattice. It is concluded that extreme caution must be used when employing this preparation technique for studies of cell architecture, and that extensive washing of cell components in distilled water may be necessary to obtain faithful representations of cell structure. PMID:6338243

Miller, K R; Prescott, C S; Jacobs, T L; Lassignal, N L

1983-02-01

215

BAM Media M30b: Freezing medium  

Center for Food Safety and Applied Nutrition (CFSAN)

... BAM Media M30b: Freezing medium. January 2001. Bacteriological Analytical Manual. M30b Freezing medium for Campylobacter. ... More results from www.fda.gov/food/foodscienceresearch/laboratorymethods

216

Aspects of Freezing Rain Simulation and Testing.  

National Technical Information Service (NTIS)

The paper examines first the available information on freezing rain and freezing drizzle in an attempt to define the applicable parameters, viz. temperature, precipitation rate (or liquid water content), drop size, and wind speed, in order to permit repre...

J. R. Stallabrass

1983-01-01

217

Standardization of Freeze Frame TV Codecs.  

National Technical Information Service (NTIS)

The purpose of this report is to recommend a protocol and a compression technique to be considered as the standard for freeze frame teleconferencing equipments. The recommendations in Section 4 is based on (a) an analysis of freeze frame teleconferencing ...

1990-01-01

218

Karen Johnson Freeze Fellowship Fund  

Microsoft Academic Search

The Karen Johnson Freeze Fellowship Fund is an initiative of the Foundation for the History of Technology (SHT) and the Society for the History of Technology (SHOT) to encourage research in the field of history of technology in Central, Southeastern, and Eastern Europe. The fund also wants to contribute to the internatio- nal dissemination of research results. The Karen Johnson

J. W. A. Korsten

219

Time dependence of immersion freezing  

NASA Astrophysics Data System (ADS)

The time dependence of immersion freezing was studied for temperatures between 236 K and 243 K. Droplets with single immersed, size-selected 400 nm and 800 nm kaolinite particles were produced at 300 K, cooled down to supercooled temperatures typical for mixed-phase cloud conditions, and the fraction of frozen droplets with increasing residence time was detected. To simulate the conditions of immersion freezing in mixed-phase clouds we used the Zurich Ice Nucleation Chamber (ZINC) and its vertical extension, the Immersion Mode Cooling chAmber (IMCA). We observed that the frozen fraction of droplets increased with increasing residence time in the chamber. This suggests that there is a time dependence of immersion freezing and supports the importance of a stochastic component in the ice nucleation process. The rate at which droplets freeze was observed to decrease towards higher temperatures and smaller particle sizes. Comparison of the laboratory data with four different ice nucleation models, three based on classical nucleation theory with different representations of the particle surface properties and one singular, suggest that the classical, stochastic approach combined with a distribution of contact angles is able to reproduce the ice nucleation observed in these experiments most accurately. Using the models to calculate the increase in frozen fraction at typical mixed-phase cloud temperatures over an extended period of time, yields an equivalent effect of -1 K temperature shift and an increase in time scale by a factor of ~10.

Welti, A.; Lüönd, F.; Kanji, Z. A.; Stetzer, O.; Lohmann, U.

2012-05-01

220

Freezing Tolerance in Mytilus Edulis.  

National Technical Information Service (NTIS)

Mytilus edulis tolerates freezing to a tissue temperature of -10 deg C, while Venus mercenaria tolerates only -6 deg C. In both species, tissues are injured when 64 per cent of cellular water has been moved to form ice. In Mytilus, 20 percent of cell wate...

R. J. Williams

1969-01-01

221

Ice Accretion in Freezing Rain.  

National Technical Information Service (NTIS)

This report describes a detailed heat-balance ice accretion model, including the important heat fluxes in freezing rain and allowing the accretion of runoff water in the form of icicles. It also presents a simple algorithm for calculating the ice load on ...

K. F. Jones

1996-01-01

222

Endocytotic activity of kitten odontoblasts in early dentinogenesis. 1. Thin section and freeze-fracture study.  

PubMed Central

The morphological features of odontoblast processes in young kitten odontoblasts were studied by thin section and freeze-fracture electron microscopy. Freeze-fracture replication revealed depressions with particles on the plasma membranes of the proximal parts of odontoblast processes. Comparison with thin sections suggested that these depressions represented sites of endocytosis. Frequent depressions with particles (corresponding to coated pits in thin sections) indicate the high absorptive activity of young odontoblasts. The results indicate that odontoblasts, especially in the proximal parts of their processes, play a significant functional role in the modification of the predentine matrix during early dentinogenesis. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8

Sasaki, T; Tominaga, H; Higashi, S

1984-01-01

223

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

Microsoft Academic Search

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

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

1981-01-01

224

Physiological responses to freezing in hatchlings of freeze-tolerant and -intolerant turtles  

Microsoft Academic Search

Freeze tolerance is a complex cold-hardiness adaptation that has independently evolved in a diverse group of organisms, including several ectothermic vertebrates. Because little is known about the mechanistic basis for freeze tolerance in reptiles, we compared responses to experimental freezing in winter-acclimatized hatchlings representing nine taxa of temperate North American turtles, including ones that tolerated freezing and others that did

Jon P. Costanzo; Patrick J. Baker; Richard E. Lee Jr

2006-01-01

225

Atmospheric Freeze Drying—A Review  

Microsoft Academic Search

This review article focuses on the development of atmospheric freeze drying (AFD): technological aspects, product possibilities, physical properties of products, drying kinetics, modeling, and simulation. The main motivation for developing atmospheric freeze drying as a new drying technology is the desire to reduce the energy consumption compared to vacuum freeze drying while maintaining a high product quality. One technical solution

I. C. Claussen; T. S. Ustad; I. Strømmen; P. M. Walde

2007-01-01

226

Molten salt freeze seal. Final report  

Microsoft Academic Search

This report documents the results of the testing performed at Sandia National Laboratory, Albuquerque, New Mexico, on the applicability of a sodium freeze seal type valve stem in a molten salt environment. The freeze seal tests consisted of cycling the valve stem at set temperature intervals, checking the temperature distribution for freeze plug location, and verifying the actuator forces. In

Corugedo

1985-01-01

227

Effects of Yeast Freezing in Frozen Dough  

Microsoft Academic Search

Cereal Chem. 80(4):454-458 The effects of freezing and frozen storage of bread dough and com- pressed yeast on bread quality were studied. Besides, the effects of compressed yeast freezing on cell viability, gas production and release of substances by the yeast cells were examined. Freezing and frozen storage of dough made with fresh yeast had more negative effects on baking

Pablo D. Ribotta; Alberto E. León; María Cristina Añón

2003-01-01

228

a Laboratory Investigation of Droplet Freezing  

Microsoft Academic Search

Laboratory experimentation was undertaken to investigate the effects of various soluble and insoluble nuclei on the freezing temperature of water droplets. The freezing temperature and size of over 15,000 droplets were obtained. Pure water was produced, and subsequently frozen in droplet form. The freezing temperatures of various sizes of pure water droplets were used as a reference standard for the

Thomas E. Hoffer

1961-01-01

229

[Recited depression].  

PubMed

Several subjects who tell their depression and play a part of it in front of the doctor without being really depressed are reported. Some of them try to hide the symptoms (irritability or erethism, ceremonials of obsessive neurosis, shunning of phobia) which, in their opinion, might be detrimental to their reputation. Others neglect to describe some of the symptoms of their polymorphous clinical picture only underlining the depressive signs. Some others play a part of depression because they have believed to recognize themselves in persons presented by mass media, because it seems to them a duty to show an adequate depression in case of mournful event, or because they "convert" their problem into a depression. Some others use depression as a blackmail, or to obtain an advantage from doctor's conviction about their illness. The reason for the high frequency of similar cases in the present time are examined: the scientific divulgation and the acceptance of depression by the modern society are among the most important ones. The peculiar semantic vicissitudes of the word depression are also reviewed. A widening of the boundaries of depression has contributed to an increase in the number of the cases. Finally, in addition to patients who are depressed without being aware of it, the authors focus the inverse possibility: patients who believed or try to make their doctor believe (playing the part of depression in front of them) that they are depressed. PMID:6599930

Barucci, M; Cossio, M

230

Assessment of molten-salt solar central-receiver freeze-up and recovery events  

SciTech Connect

Molten salt used as a heat transfer fluid in central-receiver so ar power plants has a high freezing point (430{degrees}F (221{degrees}C)). It is very likely during the life of the plant that the receiver will accidentally freeze up due to equipment malfunction or operator error. Experiments were conducted to measure the effects of a molten salt receiver freeze-up and recovery event and methods to thaw the receiver. In addition, simulated freeze/thaw experiments were conducted to determine what happens when salt freezes and is thawed in receiver tubes and to quantify the damage caused to candidate receiver tube materials. Fourteen tube samples of various materials, diameters and wall thicknesses were tested to destruction. Results of these tests are presented in this paper.

Pacheco, J.E.; Dunkin, S.R.

1996-02-01

231

Postpartum Depression  

MedlinePLUS Videos and Cool Tools

... Research Into Postpartum Depression Postpartum depression may be one of the most under-recognized and under-treated disorders. Yet, it impacts the lives of hundreds of thousands of new mothers. This video looks at those ...

232

Postpartum Depression  

MedlinePLUS

... be reprinted for personal, noncommercial use only. Postpartum depression By Mayo Clinic staff Original Article: http://www.mayoclinic.com/health/postpartum-depression/DS00546 Definition Symptoms Causes Risk factors Complications Preparing ...

233

Postpartum Depression  

MedlinePLUS

... do not need treatment. The symptoms of postpartum depression last longer and are more severe. You may ... treatment right away, often in the hospital. Postpartum depression can begin anytime within the first year after ...

234

Postpartum depression  

MedlinePLUS

... therapy if you have postpartum depression. Having good social support from family, friends, and coworkers may help reduce ... Having good social support from family, friends, and coworkers may ... seriousness of postpartum depression, but may not prevent it. ...

235

Heat pump with freeze-up prevention  

DOEpatents

What is disclosed is a heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating the fluid in heat exchange relationship with a refrigerant fluid; at least two refrigerant heat exchangers, one for effecting heat exchange with the fluid and a second for effecting heat exchange between refrigerant and a heat exchange fluid and the ambient air; a compressor for efficiently compressing the refrigerant; at least one throttling valve for throttling liquid refrigerant; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circulating device and heat exchange fluid circuit for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and direction of flow of the refrigerant therethrough for selecting a particular mode of operation. The heat exchange fluid prevents freeze up of the second heat exchanger by keeping the temperature above the dew point; and, optionally, provides heat for efficient operation.

Ecker, Amir L. (Dallas, TX)

1981-01-01

236

Prediction of high-temperature thermodynamic properties of mixed electrolyte solutions including solubility equilibria, vapor pressure depression and boiling point elevation  

SciTech Connect

The Pitzer ion-interaction model, which is theoretically derived but uses empirical parameters evaluated from experimental data on binary and ternary aqueous mixtures, is shown to accurately predict thermodynamic properties of aqueous eletrolytes to high temperatures and concentrations and for more complex compositions. Applications of the model include calculations of solubility equilibria, vapor pressures and boiling points of electrolyte mixtures. Examples of these calculations are given below. 32 refs., 5 figs., 2 tabs.

Pabalan, R.T.; Pitzer, K.S.

1988-01-01

237

Isotope quantum effects in water around the freezing point  

Microsoft Academic Search

We have measured the difference in electronic structure factors between liquid H2O and D2O at temperatures of 268 and 273 K with high energy x-ray diffraction. These are compared to our previously published data measured from 279 to 318 K. We find that the total structural isotope effect increases by a factor of 3.5 over the entire range, as the

R. T. Hart; Q. Mei; C. J. Benmore; J. C. Neuefeind; J. F. C. Turner; M. Dolgos; B. Tomberli; P. A. Egelstaff; SUF-USR

2006-01-01

238

Organic Absorbents for Triple Point Absorption Freeze Crystallization Processes.  

National Technical Information Service (NTIS)

Calculations were made to predict the absorption characteristics of various classes of organic molecules. Pertinent absorption refrigeration characteristics were found to be water-absorbent composition, miscibility of the absorbent and absorbed water, and...

J. A. Heist

1982-01-01

239

AC Corona in Foul Weather I-Above Freezing Point  

Microsoft Academic Search

After a brief survey of water appearance in the close-to-ground layer of atmosphere, behavior of water drops in the electric field is analyzed and the mechanism of streamer formations shown. Water influence, causing corona increase, has two components: (1) discharges between conductor and passing drops and (2) streamers produced by water presence on the conductor. Results of some attempts to

L. Boulet; B. J. Jakubczyk

1964-01-01

240

Psychosocial treatments for adolescent depression  

Microsoft Academic Search

Major Depressive Disorders affect between 2% and 5% of adolescents at any one point in time. Depression in adolescence is associated with serious psychosocial deficits and has negative effects on functioning during young adulthood. Starting with the pioneering work of Lenore Butler and her colleagues, many psychosocial interventions have been developed and studied, with generally positive results. On the basis

Peter M Lewinsohn; Gregory N Clarke

1999-01-01

241

Freeze chromatography method and apparatus  

DOEpatents

A freeze chromatography method and apparatus are provided which enable separation of the solutes contained in a sample. The apparatus includes an annular column construction comprising cylindrical inner and outer surfaces defining an annular passage therebetween. One of the surfaces is heated and the other cooled while passing an eluent through the annular passageway so that the eluent in contact with the cooled surface freezes and forms a frozen eluent layer thereon. A mixture of solutes dissolved in eluent is passed through the annular passageway in contact with the frozen layer so that the sample solutes in the mixture will tend to migrate either toward or away the frozen layer. The rate at which the mixture flows through the annular passageway is controlled so that the distribution of the sample solutes approaches that at equilibrium and thus a separation between the sample solutes occurs. 3 figs.

Scott, C.D.

1987-04-16

242

Neuropathy in non-freezing cold injury (trench foot).  

PubMed Central

Non-freezing cold injury (trench foot) is characterized, in severe cases, by peripheral nerve damage and tissue necrosis. Controversy exists regarding the susceptibility of nerve fibre populations to injury as well as the mechanism of injury. Clinical and histological studies (n = 2) were conducted in a 40-year-old man with severe non-freezing cold injury in both feet. Clinical sensory tests, including two-point discrimination and pressure, vibration and thermal thresholds, indicated damage to large and small diameter nerves. On immunohistochemical assessment, terminal cutaneous nerve fibres within the plantar skin stained much less than in a normal control whereas staining to von Willebrand factor pointed to increased vascularity in all areas. The results indicate that all nerve populations (myelinated and unmyelinated) were damaged, possibly in a cycle of ischaemia and reperfusion. Images Figure 1 a Figure 1 b Figure 2 a Figure 2 b Figure 3 a Figure 3 b

Irwin, M S; Sanders, R; Green, C J; Terenghi, G

1997-01-01

243

Atypical depression.  

PubMed

The authors conducted Pubmed searches to examine the epidemiological characteristics, symptoms, association with bipolar disorder, personality and temperament features, biology, and pharmacotherapy response of atypical depression and significance of current knowledge about this subtype of depression in treatment planning. Atypical depression has a high prevalence rate, starts early in life, tends to last longer, is more likely to occur in people with bipolar disorder, has high comorbidity of anxiety disorders, carries more risk of suicidal behavior, and has distinct personality psychopathology and biological traits. Atypical depression is an important specifier with significance in terms of predicting clinical course of depression, and hence in treatment planning and service use. PMID:21103169

Singh, Tanvir; Williams, Kristi

2006-04-01

244

Atypical Depression  

PubMed Central

The authors conducted Pubmed searches to examine the epidemiological characteristics, symptoms, association with bipolar disorder, personality and temperament features, biology, and pharmacotherapy response of atypical depression and significance of current knowledge about this subtype of depression in treatment planning. Atypical depression has a high prevalence rate, starts early in life, tends to last longer, is more likely to occur in people with bipolar disorder, has high comorbidity of anxiety disorders, carries more risk of suicidal behavior, and has distinct personality psychopathology and biological traits. Atypical depression is an important specifier with significance in terms of predicting clinical course of depression, and hence in treatment planning and service use.

Williams, Kristi

2006-01-01

245

Freeze concentration beats the heat  

Microsoft Academic Search

This paper reports on freeze concentration (FC) which saves energy and money in packaging, shipping, and storing food products. FC---in contrast to existing heat-evaporation processes---retains volatile flavor and aroma compounds in food products so that no additives are required to restore the taste and smell of the original product. In recent tests on orange, grapefruit, and pineapple juices, reconstituted FC

1990-01-01

246

Moisture measurement: a new method for monitoring freeze-drying cycles.  

PubMed

Quality of the final product largely depends on the freeze-drying process. In turn this largely depends on an adequate control of the amount of residual moisture after freeze-drying. Measuring this amount in the chamber of the freeze-dryer to determine the end point of sublimation and the end point of secondary drying provides a reliable control with regard to the methods traditionally used (for example rapid increase in product temperature). The purpose of this study is to evaluate the benefits and disadvantages of the different methods recommended for the monitoring of a freeze-drying cycle. Two systems for the measurement of the moisture in the freeze dryer are evaluated here: the Pirani vacuum gauge, and the moisture sensor. The moisture sensor appears to be the most sensitive and reliable way of determining both the end of sublimation and the end of secondary drying of the full load batch when placed on a freeze-dryer. The immediate benefit for the industry is to allow to scale-up without the risks of under or over estimating the freeze-drying cycle. PMID:8120734

Bardat, A; Biguet, J; Chatenet, E; Courteille, F

247

The thermodynamics of freezing soils  

NASA Astrophysics Data System (ADS)

In this work a throughout derivation of the soil freezing process is performed, from the thermodynamic equilibrium to the derivation of the water and ice content in the ground. Starting from a capillary tube schematization for the soil and the findings of Loch (1978), the generalized Clapeyron equation may be directly obtained by the Gibbs-Duhem identity. In this equation, however, the ice pressure complicates the formulation as it adds an unknown to the thermodynamic equilibrium. The only way to obtain the common generalized Clapeyron equation often used in literature is to hypothesize the behavior ''freezing=drying'' as proposed by Miller (1963). In this case the pressure at the ice-water interface is equal to the air-water interface, and so the ice pressure may be set constant and equal to the zero gauge pressure given by air pressure. This assumption, often tacitly assumed in literature, implies precise limitations on the physical processes that may be dealt with. In particular, frost heave may not be modeled. The objective of this work is to derive the thermodynamic equilibrium of the ice and water phases in a porous medium, to clarify the ''freezing=drying'' assumption and to propose a fully explicit formulation for the equilibrium where the ice pressure is added to the set of unknowns.

Dall'Amico, Matteo; Rigon, Riccardo; Gruber, Stephan; Endrizzi, Stefano

2010-05-01

248

A section press and low elemental support for enhanced preparation of freeze-dried cryosections.  

PubMed

A press- and specimen holder system is described, whereby thin, freeze-dried cryosections can be obtained more conveniently and with greater protection against contamination and harmful temperature fluctuations. The use of a grid and retainer assembly as the basic working unit, greatly facilitates low temperature work particularly when delicate grids are preferable from an analytical point of view. A new press has been constructed in order to keep the sections permanently pressed during freeze-drying and rewarming. The press also protects the sections during transfer to an external freeze-dryer. PMID:6716461

Tvedt, K E; Kopstad, G; Haugen, O A

1984-03-01

249

Survival of freezing by free-living Antarctic soil nematodes.  

PubMed

Free-living microbivorous nematodes become numerically dominant in Antarctic terrestrial faunas as environmental conditions become more severe, while also reaching very high levels of abundance in moist, vegetated habitats. Nematodes have little resistance to freezing via exogenous ice nucleation, such as would occur as their microhabitat freezes. We report the results of experiments testing the ability of seven maritime Antarctic nematode taxa to survive freezing in small water droplets at high sub-zero temperatures. Isolated individuals of these species possessed supercooling characteristics similar to those previously reported (supercooling points -6 to -25 degree C). When frozen in water at -3 to -6 degree C, most showed high (> 70%) survival both (i) after rapid cooling (1 degree C/min) to c. -60 degree C followed by immediate rewarming, and (ii) when held for 7-12 h at either -10 or -30 degree C, although the proportions surviving varied between species. We propose that the ability to survive freezing while fully hydrated at high sub-zero temperatures is one of the most important aspects of these species' survival tactics. PMID:12148024

Convey, P; Worland, M R

250

Contact freezing: a review of experimental studies  

NASA Astrophysics Data System (ADS)

This manuscript compiles both theoretical and experimental information on contact freezing with the aim to better understand this potentially important but still not well quantified heterogeneous freezing mode. There is no complete theory that describes contact freezing and how the energy barrier has to be overcome to nucleate an ice crystal by contact freezing. Experiments on contact freezing conducted using the cold plate technique indicate that it can initiate ice formation at warmer temperatures than immersion freezing. Additionally, a qualitative difference in the freezing temperatures between contact and immersion freezing has been found using different instrumentation and different ice nuclei. There is a lack of data on collision rates in most of the reported data, which inhibits a quantitative calculation of the freezing efficiencies. Thus, new or modified instrumentation to study contact nucleation in the laboratory and in the field are needed to identify the conditions at which contact nucleation could occur in the atmosphere. Important questions concerning contact freezing and its potential role for ice cloud formation and climate are also summarized.

Ladino Moreno, L. A.; Stetzer, O.; Lohmann, U.

2013-10-01

251

Improved Cryofixation Applicable to Freeze Etching  

PubMed Central

Freeze etching of solute model systems (e.g., glycerol or ferritin solutions) demonstrates that cryofixation can introduce serious artifacts due to the segregation of the dissolved or dispersed material from the solvent. Since, in principle, this problem can be reduced by increasing the cooling rate, a new technique has been developed which combines spray freezing with freeze etching. This spray-freeze-etching is applied by first spraying the specimen into a liquid cryomedium. The frozen droplets are then “glued” together with butylbenzene to form a regular freeze-etch specimen, while the temperature of the sample is kept at -85°C. The results obtained by spray-freeze-etching are far superior to those obtained by standard freezing. Our results, using 5% glycerol as a test specimen, are equivalent to those obtained by the high-pressure method (1). The reduction of segregation during freezing makes freeze etching a method applicable for the investigation of solute systems. Furthermore, the study of unicellular organisms or cellular fractions by freeze etching without the use of antifreeze is made possible. Images

Bachmann, L.; Schmitt, W. W.

1971-01-01

252

Geriatric Depression in Primary Care  

PubMed Central

Primary care settings present important opportunities for the detection and management of depression in older adults. As many as 10 % of older adults presenting in primary care have clinically significant depression, but only about half are recognized and only one in five depressed older adults receive effective treatment in primary care. We review common barriers to effective treatment such as atypical clinical presentations and comorbid medical conditions that are common in older adults. We identify treatment strategies such as measurement-based stepped care and collaborative care that can substantially improve the effectiveness of treatment in this setting and we highlight opportunities for addressing health disparities in geriatric depression care. We also point out the importance of engaging and supporting family caregivers of depressed older adults. We conclude by identifying three strategic areas to improve the treatment of geriatric depression in primary care: activation and engagement of patients and family members, health care provider training, and broader system changes.

Park, Mijung; Unutzer, Jurgen

2011-01-01

253

Melting point elevation in compatible polymer blends  

Microsoft Academic Search

Summary An expression is presented which relates the experimentally observed melting point depression in crystallizable, compatible polymer blends to changes in lamellar thickness and thermodynamic considerations.

J. Runt; P. B. Rim; S. E. Howe

1984-01-01

254

Freeze-drying of spermatozoa.  

PubMed

Bull semen was diluted to a concentration of 2 X 10(8) cells/ml, cooled to 5 degrees C in 5 h, frozen in 0.025 ml spheres on the surface of solid carbon dioxide, and stored in liquid nitrogen. 50% by volume of the diluent was 325 m0sm Tes:N-tris (hydroxymethyl) methyl-2-amino ethane sulfonic acid titrated to pH 7.2 with 325 m0sm Tris:tris (hydroxymethyl) amino methane. The diluent also contained 30% by volume isotonic sodium citrate and 20% by volume egg yolk. The frozen spermatozoa were freeze-dried in 400 mg quantities in test tubes at -50 degrees C with a condenser at -196 degrees C. Moisture content was determined by weighing the individual samples before and after freeze-drying. Drying the samples for several days at 20 degrees C removed 868 mg from each gram of frozen material and this was considered the zero moisture level. Samples were stored at 20 degrees C or -196 degrees C after freeze-drying. The freezer-dried samples were rehydrated by flooding with five times their original volume of isotonic sodium citrate. Tests of the recovered spermatozoa included percentage motile cells, acrosome damage, enzyme release, protein denaturation, hypotonic swelling and fertility testing. Sperm motility decreased with dryness until it reached zero at 3% moisture. Acrosome morphology and enzyme release appeared normal down to 1% moisture. Preliminary results showed some fertility at all levels of dryness with -196 degrees C storage, and fertility at less than 1% moisture with 20 degrees C storage. Additional fertility testing is underway. PMID:1030432

Larson, E V; Graham, E F

1976-10-01

255

Freeze Drying: Potential for Powdered Nanoparticulate Product  

Microsoft Academic Search

Nanoparticles were prepared by using an emulsion solvent evaporation method. Further, the drying of an anti-cancer drug of proprietary nature (nanosized) was carried out by a freeze-drying technique to get a free-flowing powder. A systematic approach was developed to study the freeze-drying technique for polymeric nanoparticles. Initially, the freeze-thawing experiments were carried out with varying concentrations of cryoprotectants to screen

V. V. Patil; P. P. Dandekar; V. B. Patravale; B. N. Thorat

2010-01-01

256

Freeze-Drying Characteristics of Tropical Fruits  

Microsoft Academic Search

The objective of this work was to experimentally determine physical properties such as apparent densities, real densities, and porosity of freeze-dried tropical fruits pulps such as pineapple, Barbados cherry, guava, papaya, and mango, and to carry out nutritional analysis of vitamin C, calcium, and phosphorus in the freeze-dried and in natura pulps. The freeze-dried pulps presented low apparent density and

Ana M. Silveira; José T. Freire

2006-01-01

257

A Bilateral Nuclear-Weapon Freeze  

Microsoft Academic Search

A bilateral nuclear-weapons freeze to stop the arms race is, next to the economy, the major public issue. The author feels that a freeze would lessen the risk of launch-on-warning errors that could lead to nuclear war. Further, a bilateral freeze would preserve the parity of existing US-Soviet arms, but prevent the destabilization of a new counterforce capability. It must

Randall Forsberg

1982-01-01

258

DNA Denaturation Under Freezing in Alkaline Medium  

Microsoft Academic Search

It is generally accepted that DNA conserves its secondary structure after a freeze-thaw cycle. A negligible amount of degradation occurs after this procedure. Degradation becomes appreciable only after multiple cycles of freezing and thawing. In this study, we have found that a single freeze-thaw cycle in alkaline medium (pH ? 10.8) gives rise to denaturation of calf thymus DNA, although

Elena N. Galyuk; Roger M. Wartell; Yury M. Dosin; Dmitri Y. Lando

2009-01-01

259

Predicting Freezing for Some Repulsive Potentials  

SciTech Connect

We propose a simple method to approximately predict the freezing (fluid-solid) phase transition in systems of particles interacting via purely repulsive potentials. The method is based on the striking universality of the freezing curve for the model Yukawa and inverse-power-law interactions. This method is applied to draw an exemplary phase diagram of complex plasmas. We suggest that it can also be used to locate freezing transition in other substances with similar properties of interaction.

Khrapak, S. A.; Morfill, G. E. [Max-Planck-Institut fuer extraterrestrische Physik, D-85741 Garching (Germany)

2009-12-18

260

Urban Modification of Freezing-Rain Events  

Microsoft Academic Search

A new national database for freezing-rain occurrences during the 1945-2000 period provided an opportunity for a study of the potential urban effects on freezing-rain events. Numerous past studies of snowfall events in urban areas have defined decreases of 10%-35% related to the urban heat island. The heat island, which acts to elevate near-surface temperatures, could also keep some freezing-rain situations

2003-01-01

261

Scanning electron microscopy of muscle myofibrils after high pressure freezing and freeze-substitution-staining.  

PubMed

A novel approach to study the three dimensional ultrastructure of organelles and cells by means of scanning electron microscopy is described. Muscle myofibrils have been used in the development of the techniques since their structure is well characterized using conventional electron microscopic methods. Myofibrils in rigor buffer (with no cryo-protectants or pressure sealants) were frozen at high pressure (2300 bar) within specially designed chambers. The frozen specimens were then freeze-substituted-stained with methanol containing tungsten and iron salts and finally critical point dried. These methods allowed scanning electron microscopic observations of the organization of individual filaments within whole myofibrils over several sarcomeres. Images obtained showed excellent structural preservation with three dimensional information which is not available with other electron microscopic techniques. Success in these approaches was ascribed to (a) rapid and uniform freezing at high pressure without ice segregation patterns, (b) uniform electro-conductivity of the specimen closely attached to the polished carbon piston/carrier, and (c) good electron emission (secondary and back-scattered) from the metal incorporated into the myofibril structure without additional coating. PMID:7686303

Malecki, M; Greaser, M L

1993-03-01

262

[Social egg freezing: Which problems?].  

PubMed

In today's society, many women push pregnancy further away from the "right" childbearing age. Assisted reproduction, except egg donation, is unable to fully overcome the effect of age on fertility loss. The effectiveness of oocyte vitrification is demonstrated, and oocyte vitrification is allowed in the French Bioethics law of 2011. In the French law, oocyte' s cryopreservation is proposed to oocyte donors without child. Social egg freezing for non-medical reason is already legal in some countries, but leads to new debates and discussions. PMID:23972923

Belaisch-Allart, J; Brzakowski, M; Chouraqui, A; Grefenstette, I; Mayenga, J-M; Muller, E; Belaid, Y; Kulski, O

2013-08-21

263

Models and Characteristics of Freezing Rain and Freezing Drizzle for Aircraft Icing Applications.  

National Technical Information Service (NTIS)

A large, new database of in-flight measurements of icing-related cloud and atmospheric variables in freezing rain and freezing drizzle conditions is used to help determine the range of temperatures, altitudes, exposure durations, icing intensities, precip...

R. K. Jeck

2010-01-01

264

Reptile freeze tolerance: metabolism and gene expression.  

PubMed

Terrestrially hibernating reptiles that live in seasonally cold climates need effective strategies of cold hardiness to survive the winter. Use of thermally buffered hibernacula is very important but when exposure to temperatures below 0 degrees C cannot be avoided, either freeze avoidance (supercooling) or freeze tolerance strategies can be employed, sometimes by the same species depending on environmental conditions. Several reptile species display ecologically relevant freeze tolerance, surviving for extended times with 50% or more of their total body water frozen. The use of colligative cryoprotectants by reptiles is poorly developed but metabolic and enzymatic adaptations providing anoxia tolerance and antioxidant defense are important aids to freezing survival. New studies using DNA array screening are examining the role of freeze-responsive gene expression. Three categories of freeze responsive genes have been identified from recent screenings of liver and heart from freeze-exposed (5h post-nucleation at -2.5 degrees C) hatchling painted turtles, Chrysemys picta marginata. These genes encode (a) proteins involved in iron binding, (b) enzymes of antioxidant defense, and (c) serine protease inhibitors. The same genes were up-regulated by anoxia exposure (4 h of N2 gas exposure at 5 degrees C) of the hatchlings which suggests that these defenses for freeze tolerance are aimed at counteracting the injurious effects of the ischemia imposed by plasma freezing. PMID:16321368

Storey, Kenneth B

2006-02-01

265

Mechanism of freeze-drying drug nanosuspensions.  

PubMed

Drug nanoparticles prepared in a liquid medium are commonly freeze-dried for the preparation of an oral dosage in solid dosage form. The freezing rate is known to be a critical parameter for redispersible nanoformulations. However, there has been controversy as to whether a fast or slow freezing rate prevents irreversible aggregation. A systematic investigation is presented herein regarding the effect of both the molecular weight of the cryoprotectant and the freezing rate in order to elucidate the mechanism underlying irreversible aggregation. It was found that irreversible aggregation occurred during drying rather than freezing, although a proper freezing rate is critical. A more homogeneous distribution of the cryoprotectant and drug nanoparticles led to more redispersible powders. Thus, keeping the local concentration distribution of the nanoparticles and cryoprotectant fixed during the freezing step plays a critical role in how the freezing rate affects the redispersibility. The kinetic approach of excluding the tendency of ice crystal growth permitted an explanation of the controversial results. This study will facilitate an in-depth understanding of the aggregation process of nanoparticles or proteins during freeze-drying. PMID:22877696

Chung, Nae-Oh; Lee, Min Kyung; Lee, Jonghwi

2012-08-07

266

Coagulation size of freezable water in poly(vinyl alcohol) hydrogels formed by different freeze\\/thaw cycle periods  

Microsoft Academic Search

The coagulation size of freezable water in a poly(vinyl alcohol) (PVA) hydrogel was investigated as a function of the freeze\\/thaw cycle period using thermal analysis. The melting temperature of ice in the gel shifted to a lower temperature than that of normal ice. This temperature depression can be interpreted in terms of the coagulation size of freezable water in the

Tatsuro Nakano; Takahiko Nakaoki

2011-01-01

267

Role of saccharides for the freeze-thawing and freeze drying of liposome  

Microsoft Academic Search

For the preservation of liposomes, freeze-thawing and freeze-drying have been studied by various workers with saccharides (SA) and a freeze-dried liposome preparation is now commercially available. However, the mechanism of stabilizing action of SA in these processes, especially freeze-drying, is not yet fully understood. The interaction of egg yolk phosphatidylcholine (EPC: liquid crystaline state) and DPPC (gel state) liposomes with

Koichiro Miyajima

1997-01-01

268

Sensitivity of the Global Distribution of Cirrus Ice Crystal Concentration to Heterogeneous Freezing (Invited)  

NASA Astrophysics Data System (ADS)

This study presents the sensitivity of global ice crystal number concentration, Nc, to the parameterization of heterogeneous ice nuclei (IN). Simulations are carried out with the NASA Global Modeling Initiative (GMI) chemical and transport model coupled to an analytical ice microphysics parameterization. Heterogeneous freezing is described using nucleation spectra derived from theoretical and empirical considerations, considering dust, black carbon, ammonium sulfate, and glassy aerosol as IN precursors. When competition between homogeneous and heterogeneous freezing is considered, global mean Nc vary by up to a factor of twenty depending on the heterogeneous freezing spectrum used. IN effects on Nc strongly depend on dust and black carbon concentrations, and are strongest under conditions of weak updraft and high temperature. Regardless of the heterogeneous spectrum used, dust is an important contributor of IN over large regions of the northern hemisphere. Black carbon however exhibits appreciable effects on when the freezing fraction is greater than 1%. Compared to in situ observations, Nc is overpredicted at temperatures below 205 K, even if a fraction of liquid aerosol is allowed to act as glassy IN. Assuming that cirrus formation is forced by weak updraft addressed this overprediction but promoted heterogeneous freezing effects to the point where homogeneous freezing is inhibited even for IN concentrations as low as 1 L-1. Chemistry and dynamics must be considered to explain cirrus characteristics at low temperature. Only cloud formation scenarios where competition between homogeneous and heterogeneous freezing is the dominant feature would result in maximum supersaturation levels consistent with observations.

Nenes, A.; Barahona, D.; Rodriguez, J. M.

2010-12-01

269

Ice VI freezing of meat: supercooling and ultrastructural studies  

Microsoft Academic Search

While “classical” freezing (to ice I) is disruptive to the microstructure of meat, freezing to ice VI has been found to preserve it. Ice VI freeze-substitution microscopy showed no traces of structural alteration on muscle fibres compared with the extensive damage caused by ice I freezing. The different signs of the freezing volume changes associated with these two ice phases

Antonio D Molina-Garc??a; Laura Otero; Miriam N Martino; Noem?? E Zaritzky; Jacek Arabas; Janusz Szczepek; Pedro D Sanz

2004-01-01

270

Food freezing with simultaneous surface dehydration: approximate prediction of freezing time  

Microsoft Academic Search

Freezing of unpackaged foods induces mass transfer in the form of surface ice sublimation, which in turn modifies heat transfer conditions. At present there are no simplified methods for predicting freezing times when surface dehydration occurs. This paper uses a previously developed model for the simulation of simultaneous heat and mass transfer during food freezing and storage to generate a

Laura A. Campañone; Viviana O. Salvadori; Rodolfo H. Mascheroni

2005-01-01

271

Effect of power ultrasound on freezing rate during immersion freezing of potatoes  

Microsoft Academic Search

Immersion freezing of potatoes with the aid of power ultrasound was investigated. The effect of power ultrasound on freezing rate was influenced by ultrasound power, exposure time and the freezing phase to which ultrasound was applied. The higher the ultrasound power and the longer the exposure time, the stronger the sonication was. However, the ultrasound power and exposure time should

Bing Li; Da-Wen Sun

2002-01-01

272

Screening for postnatal depression in primary care: cost effectiveness analysis  

Microsoft Academic Search

Objective To evaluate the cost effectiveness of routine screening for postnatal depression in primary care.Design Cost effectiveness analysis with a decision model of alternative methods of screening for depression, including standardised postnatal depression and generic depression instruments. The performance of screening instruments was derived from a systematic review and bivariate meta-analysis at a range of instrument cut points; estimates of

Mike Paulden; Stephen Palmer; Catherine Hewitt; Simon Gilbody

2009-01-01

273

Influence of formulation pH and suspension state on freezing-induced agglomeration of aluminum adjuvants.  

PubMed

Freezing and thawing of vaccines containing aluminum adjuvants can lead to formation of aggregates and loss in vaccine potency. We sought to understand whether and to what extent the freeze-thaw damage to aluminum adjuvants would differ based on suspension state (flocculation and settlement) at the time of freezing. As flocculation and settlement characteristics of aluminum adjuvants are driven largely by the electrostatic charges on the adjuvant particles, which, in turn, are strongly influenced by the pH of the suspension, we conducted freeze-thaw studies on both Adjuphos and Alhydrogel™ samples at three pH levels (4, 6.5, and 7.2) in buffer solutions with 9% sucrose. Significantly less aggregation occurred in the buffered sucrose solutions at the pH furthest from the aluminum adjuvant point of zero charge during slow freezing at -20°C. The freezing-induced aggregation for the samples with 9% sucrose at each pH was minimal during fast freezing at -70°C and -115°C. Suspensions that were flocculated and settled to a greater extent experienced the most freeze-thaw aggregation, whereas suspensions that were frozen before significant flocculation and settlement occurred showed little or no aggregation. Because pH of formulation can affect flocculation and settling time, it indirectly affects the extent of freeze-thaw aggregation. PMID:22113733

Salnikova, Maya S; Davis, Harrison; Mensch, Christopher; Celano, Lauren; Thiriot, David S

2011-11-23

274

Postpartum depression  

Microsoft Academic Search

The aim of this study was to explore the lived experiences of postpartum depression among the Middle Eastern women living in Sydney, Australia. A phenomenologic research design was used to conduct in-depth, unstructured interviews with a purposive sample of 45 mothers who had experienced postpartum depression. The interviews were conducted in the mothers’ homes. Transcriptions of these interviews were analyzed

Violeta Lopez Nahas; Sharon Hillege; Nawal Amasheh

1999-01-01

275

Water sorption and time-dependent crystallization behaviour of freeze-dried lactose–salt mixtures  

Microsoft Academic Search

Water sorption properties of freeze-dried lactose, lactose\\/CaCl2, lactose\\/NaCl, lactose\\/MgCl2, and lactose\\/KCl mixtures in their molar ratio of (9:1) were investigated. Brunauer–Emmett–Teller (BET) and Guggenheim–Anderson–de Boer (GAB) models were used to model water sorption properties. Water is known to function as a plasticizer, depressing the glass transition and facilitating crystallization. Crystallization in the present study resulted in loss of sorbed water

A. M. Elmonsef Omar; Yrjö H. Roos

2007-01-01

276

A coupled heat and mass transfer model of pure metal freezing using comsol multiphysics{trade mark, serif}  

NASA Astrophysics Data System (ADS)

The Comsol Multiphysics{trade mark, serif} finite element simulation package is employed to simulate the freezing of a zinc fixed point for standard platinum resistance thermometer (SPRT) calibrations. The liquid-solid interface is represented by the boundary of an adaptive mesh whose geometry adjusts itself to accommodate the propagating liquid-solid interface. This means that the temperature range of freezing can be arbitrarily narrow. The evolution of the mesh as a function of time is determined by the thermal conditions. The transport of heat and impurities, particularly at the liquid-solid interface, is modeled simultaneously and the concentration of impurities in the liquid volume is evaluated as a function of time and location. Because this is a coupled simulation the influence of impurity distribution on the liquid-solid interface temperature can be characterized. Some results of the model are presented against the background of impurity effects on the freezing curves of ITS-90 fixed points. In particular, the model is employed to demonstrate the dependence of the freezing curve shape with freezing rate, and that for low freezing rates the curve shape is well described by the Scheil theory of freezing. A new method of determining the endpoint of freezing of experimental data is shown and used to compare the model with measurements.

Pearce, J. V.

2013-09-01

277

Reliable Change in Depression during Behavioral Weight Loss Treatment among Women with Major Depression  

PubMed Central

Although behavioral weight loss interventions generally have been shown to improve depressive symptoms, little is known as to whether some people with major depressive disorder experience worsening of depression during a weight loss intervention. We examined rates and predictors of change in depression symptoms among 148 obese women with major depressive disorder who participated in a trial comparing depression treatment plus behavioral weight loss treatment (Behavioral Activation; BA) to behavioral weight loss treatment alone (Lifestyle Intervention; LI). A statistically reliable change in depression was calculated as ? 9 points on the Beck Depression Inventory in this sample. At 6 months, 73% of participants in BA and 54% of participants in LI showed reliable improvement in depression symptoms and 1.5% of participants in BA and 1.3% of participants in LI showed reliable worsening in depression symptoms. Rates of reliable change were similar at 12 months. Participants who experienced reliable improvement in depression lost significantly more weight than those who did not in both conditions. In the LI condition, baseline psychiatric variables and change in physical activity during treatment were also related to reliable improvement in depression. We found no evidence for an iatrogenic effect of behavioral weight loss treatment on depressive symptoms among obese women with major depressive disorder; rather, behavioral weight loss treatment appears to be associated with significant concurrent improvement in depression. Even greater rates of reliable improvement were observed when depression treatment was added to weight loss treatment.

Busch, Andrew M.; Whited, Matthew C.; Appelhans, Bradley M.; Schneider, Kristin L.; Waring, Molly E.; DeBiasse, Michele A.; Oleski, Jessica L.; Crawford, Sybil L.; Pagoto, Sherry L.

2012-01-01

278

Older Adults and Depression  

MedlinePLUS

... If so, you may have depression. What is depression? Everyone feels down or sad sometimes, but these ... has depression. What are the different forms of depression? There are several forms of depression. The most ...

279

Freezing and Blocking of Water Pipes.  

National Technical Information Service (NTIS)

The topic addressed in this article is the freezing and blockage of water pipes that are full, with the water either flowing or still. It has long been assumed that when the water in a pipe freezes the ice begins to form on the inside surface of the pipe ...

K. L. Carey

1982-01-01

280

Rotary replication for freeze-etching  

PubMed Central

Rotary replication has been adapted to freeze-etching and evaluated using T4 polyheads, erythrocyte ghosts, and chloroplast membranes. Conventional electron microscopy, electron diffraction, and optical diffraction and filtering indicate that platinum-carbon rotary replication renders radially symmetrical contrast and 25 A resolution to freeze-etched specimens so as to clarify subunit structure not normally evident in unidirectional shadow replicas.

1977-01-01

281

Freeze conditioning agents ease winter railcar unloading  

SciTech Connect

A US midwest utility's freeze control programme is described. All coal is treated with a glycol-based freeze control agent. Some rail wagons were treated with a side release agent which stops coal sticking to the metal wagon. The use of calcium chloride or heat to thaw frozen coal is also discussed.

Olson, G.E.

1982-02-01

282

Ground freezing for containment of hazardous waste  

Microsoft Academic Search

The freezing of ground for the containment of subsurface hazardous waste is a promising method that is environmentally friendly and offers a safe alternative to other methods of waste retention in many cases. The frozen soil method offers two concepts for retaining waste. One concept is to freeze the entire waste area into a solid block of frozen soil thus

F. N. Sayles; I. K. Iskandar

1998-01-01

283

Freeze Injuries in Avocado Fruit1  

Microsoft Academic Search

Differences were found in the extent of freeze injury among 'Fuerte', 'Hass' and 'Nabal' avocados (Persea americana Mill.). Large 'Fuerte' fruit suffered more than small ones. Relatively high rates of ethylene production and of respiration were found in heavily injured fruit as soon as 1 day after harvest. Keeping quality of freeze-damaged fruit was reduced. It is concluded that the

Y. Fuchs; G. Zauberman; U. Yanko

284

Recovery of White Blood Cells After Freezing.  

National Technical Information Service (NTIS)

Whereas the red cells recover from the actual congelation of all the water freezable at -3C, the neutrophils are already injured when only a fraction of the water freezable at -1.5C is congealed. Electron microscope studies of freeze-dried or freeze-subsi...

B. J. Luyet L. J. Menz G. L. Rapatz D. Rasmussen

1971-01-01

285

Freezing Rain: An Observational and Theoretical Study  

Microsoft Academic Search

Data from a Doppler radar, an instrumented aircraft, and several rawinsonde observations during freezing rain and ice pellet events have been analyzed for this study. From these data, 34 soundings were obtained that characterized the vertical structure of the atmosphere at the time of the freezing precipitation. These soundings were analyzed to determine the general nature of the vertical structure

Ryan J. Zerr

1997-01-01

286

7 CFR 305.18 - Quick freeze treatment schedule.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 false Quick freeze treatment schedule. 305...PHYTOSANITARY TREATMENTS Quick Freeze Treatments § 305.18 Quick freeze treatment schedule. (a...United States or its territorial waters, or is otherwise disposed...

2010-01-01

287

7 CFR 305.18 - Quick freeze treatment schedule.  

Code of Federal Regulations, 2010 CFR

...2009-01-01 false Quick freeze treatment schedule. 305...PHYTOSANITARY TREATMENTS Quick Freeze Treatments § 305.18 Quick freeze treatment schedule. (a...United States or its territorial waters, or is otherwise disposed...

2009-01-01

288

BK090020 Summary - CryoMACS Freezing Bag  

Center for Biologics Evaluation and Research (CBER)

Text Version... Primary: Baxter CryocyteTM Freezing Container (BK950049) Secondary: Charter Medical Cell FreezeTM Liquid Nitrogen Freezing Container ... More results from www.fda.gov/downloads/biologicsbloodvaccines/bloodbloodproducts

289

Interdependence of Measures in Pavlovian Conditoned Freezing  

PubMed Central

Pavlovian conditioned freezing is an intensively utilized paradigm that has become a standard model of memory and cognition. Despite its widespread use, the interdependence among each measure commonly reported in fear conditioning studies has not been described. Using mice, we examine the relationship of each common freezing measure (Training Baseline, Post-Shock freezing, Contextual Fear, Tone Baseline, and Tone Fear), as well as baseline locomotor activity measures, to better understand the significance of each. Of particular interest, Post-Shock freezing appears to be a good measure of immediate contextual memory. In contrast, Tone Baseline freezing, as typically measured in a novel context, appears to be contaminated with multiple sources of fear. Finally, Contextual and Tone Fear show a weak interdependence.

Wood, Suzanne C.; Anagnostaras, Stephan G.

2011-01-01

290

DNA denaturation under freezing in alkaline medium.  

PubMed

It is generally accepted that DNA conserves its secondary structure after a freeze-thaw cycle. A negligible amount of degradation occurs after this procedure. Degradation becomes appreciable only after multiple cycles of freezing and thawing. In this study, we have found that a single freeze-thaw cycle in alkaline medium (pH>or=10.8) gives rise to denaturation of calf thymus DNA, although the melting temperature of intact DNA in the solution used for the freeze-thaw experiments is higher than 60 degrees C. The degree of denaturation is almost independent of the regime of freezing. The melting curve obtained after DNA is frozen at -2 degrees C and then thawed is almost the same as after a freezing carried out in liquid nitrogen (-196 degrees C). However, incubation in the same solution at 0 degrees C for 24 hours without freezing does not give rise to any denaturation. The degree of denaturation caused by freezing increases with pH (if pH>or=10.8) and decreases with Na2CO3 concentration at fixed pH and [Na+], although Na2CO3 decreases the melting temperature of intact DNA. A preliminary treatment of DNA with cisplatin or transplatin (0.01 Pt atoms per nucleotide) gives rise to a full recovery of the DNA secondary structure after freezing and thawing similar to what occurs after heating DNA to 100 degrees C and quick cooling. Possible mechanisms that may cause DNA denaturation during a freeze-thaw cycle in alkaline medium are discussed. PMID:19108591

Galyuk, Elena N; Wartell, Roger M; Dosin, Yury M; Lando, Dmitri Y

2009-02-01

291

[Atypical depression].  

PubMed

The principal atypical aspects of depressive disease are: minor and attenued aspects, monosymptomatic and atypical aspects (food disorders and sleep disorders), masqued aspects (somatoform, anxious, characterial and addict disorders), atypical aspects of child (anxious nevrotical disorder), pseudo-demented and characterial aspects of aged subjects. Facing to these aspects, the diagnosis of depression is evoqued on: the recent and fast advent of these disorders, their morning predominance, their recurrent character, the state of attenued depressive symptoms (anhedonia), the positive responsiveness to treatment. PMID:10337216

Escande, M; Boucard, J

1999-04-01

292

The Identification of Postpartum Depression  

PubMed Central

Postpartum depression (PPD) is the most common medical complication of childbearing. Universal screening maximizes the likelihood of prompt identification of PPD. Obstetrician-gynecologists routinely evaluate postpartum women for a general health examination and review of family planning options at approximately 6 weeks after birth; therefore, they are well-positioned to identify PPD. In this paper, we review the diagnostic criteria for postpartum depressive disorders and clinical risk factors predictive of PPD. We examine depression screening tools, appropriate cut-points associated with positive screens, the optimal timing for screening and the acceptability of depression screening in obstetrical settings. Lastly, we explore how to manage patients who screen positive for depression and treatment options for women with PPD.

Sit, Dorothy K.; Wisner, Katherine L.

2009-01-01

293

The role and clinical significance of subsyndromal depressive symptoms (SSD) in unipolar major depressive disorder  

Microsoft Academic Search

Analyses conducted in 10?526 community respondents investigated by the NIMH Epidemiological Catchment Area (ECA) Program, revealed the 1-month point prevalence of depressive symptoms and disorders in the general population, at the first ECA interview (Wave 1) to be 10%, as follows: 2.3% major depressive disorder (MDD); 2.3% dysthymic disorder (DD); 1.5% minor depressive disorder (MinD); and 3.9% subsyndromal depressive symptoms

Lewis L Judd; Hagop S Akiskal; Martin P Paulus

1997-01-01

294

Treating Depression  

MedlinePLUS Videos and Cool Tools

... cognitive behavioral therapy problem solving therapy psychodynamic therapy social skills training and supportive counseling. The data showed that all seven therapies were better at reducing symptoms of depression than usual care. Plus there were no significant differences between the ...

295

Adolescent Depression  

PubMed Central

Depression in adolescence and adulthood is common, afflicting up to 20 percent of these populations. It represents a significant public health concern and is associated with considerable suffering and functional impairment. Adolescent-onset depression tends to be a particularly malignant and recalcitrant condition, increasing the likelihood of recurrence and chronicity in adulthood. Clinical presentations for various medical and psychiatric conditions, as well as reactions to psychosocial stressors, can mimic or confound the picture of depression in adolescents. Therefore, careful assessment and differential diagnosis is essential. Effective treatments, both pharmacological and psychosocial in nature, exist, and so early detection and intervention is paramount. This article presents an overview of optimal prevention, assessment, and clinical decision-making strategies for managing depression in adolescents.

Cook, Mary N.; Peterson, John; Sheldon, Christopher

2009-01-01

296

Depression - elderly  

MedlinePLUS

... slowly than in younger adults. To better manage depression at home, you should: Exercise regularly, if your doctor says it is ok. Surround yourself with caring, positive people and fun activities. Learn good sleeping habits. Learn to ...

297

Depression (lesson)  

NSDL National Science Digital Library

Students reveal their preconceptions about depression, then use G2C Online to learn about symptoms of the disorder, genes, and neurotransmitters associated with it, and challenges involved in diagnosis and treatment.

2009-04-14

298

Chilled water coil freeze protection via internal drying  

SciTech Connect

Winter lay-up for chilled water coils has been a problem for as long as there has been air conditioning. A frozen coil may be so seriously damaged that it must be replaced. Also, as the coil thaws, significant flooding of adjacent areas may result. Over the years, various methods of freeze protection have been used. These methods include using a glycol solution to lower the freezing point, blowing the coil clear with compressed air, or installing coils that incorporate freeze plugs in the coil design. Each of these methods has one or more significant drawbacks. A new approach, nicknamed ``The LaRocca Solution`` is a simple procedure. Air is blown continuously through the coils to ensure that they become completely dry and remain so. Instead of using a separate blower or air compressor to blow out the water, the supply fan itself is used. On most medium- and high-pressure HVAC systems, the static pressure produced by the supply fan is sufficient to overcome the internal resistance of the coil tubes. One simply configures the chilled water piping in a manner that permits the coils to be drained by gravity and then purged by the discharge of the fan. The fan does all the work.

LaRocca, D.V. [Yale Univ. School of Medicine, New Haven, CT (United States). Building Services and Operations Dept.

1997-12-01

299

Transmission electron microscopy of thin sections of Drosophila: high-pressure freezing and freeze-substitution.  

PubMed

The state of the art in fine-structure preservation for thin sectioning can be achieved by using fast-freezing technology followed by freeze substitution and embedding in resin. Samples prepared by high-pressure freezing are estimated to be "fixed" in 20-50 msec. Fast freezing also freezes every cell component regardless of its chemistry. Once frozen, tissues can be processed in a variety of ways before viewing in the electron microscope; here we describe only freeze substitution. In freeze substitution, cells are dehydrated at very low temperatures and cell water is replaced with organic solvent at -80°C to -90°C. At this temperature, large molecules such as proteins are immobilized, yet smaller molecules such as water (ice) can be dissolved and replaced with organic solvents, e.g., acetone. The ideal way to do freeze substitution is with a dedicated freeze-substitution device such as the Leica AFS2 system. These devices allow programming of the times and temperatures needed. Alternatively, if this equipment is not available, freeze substitution can still be performed using items commonly found around the laboratory, as is described here. This protocol is useful for preparing thin sections of Drosophila when the best possible preservation of ultrastructure and antigenicity is required. PMID:22474654

McDonald, Kent L; Sharp, David J; Rickoll, Wayne

2012-04-01

300

Molten salt freeze seal. Final report  

SciTech Connect

This report documents the results of the testing performed at Sandia National Laboratory, Albuquerque, New Mexico, on the applicability of a sodium freeze seal type valve stem in a molten salt environment. The freeze seal tests consisted of cycling the valve stem at set temperature intervals, checking the temperature distribution for freeze plug location, and verifying the actuator forces. In addition to the test results, this report also documents the engineering analysis and other tasks performed before testing to form a basis for predicted test conditions and recommendations for the test program.

Corugedo, J.J.

1985-08-01

301

Use of manometric temperature measurement (MTM) and SMART freeze dryer technology for development of an optimized freeze-drying cycle.  

PubMed

This report provides, for the first time, a summary of experiments using SMART Freeze Dryer technology during a 9 month testing period. A minimum ice sublimation area of about 300 cm(2) for the laboratory freeze dryer, with a chamber volume 107.5 L, was found consistent with data obtained during previous experiments with a smaller freeze dryer (52 L). Good reproducibility was found for cycle design with different type of excipients, formulations, and vials used. SMART primary drying end point estimates were accurate in the majority of the experiments, but showed an over prediction of primary cycle time when the product did not fully achieve steady state conditions before the first MTM measurement was performed. Product resistance data for 5% sucrose mixtures at varying fill depths were very reproducible. Product temperature determined by SMART was typically in good agreement with thermocouple data through about 50% of primary drying time, with significant deviations occurring near the end of primary drying, as expected, but showing a bias much earlier in primary drying for high solid content formulations (16.6% Pfizer product) and polyvinylpyrrolidone (40 kDa) likely due to water "re-adsorption" by the amorphous product during the MTM test. PMID:17853427

Gieseler, Henning; Kramer, Tony; Pikal, Michael J

2007-12-01

302

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

NASA Astrophysics Data System (ADS)

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.

Marshall, Katie E.; Sinclair, Brent J.

2012-01-01

303

SEM sample preparation for cells on 3D scaffolds by freeze-drying and HMDS.  

PubMed

Common dehydration methods of cells on biomaterials for scanning electron microscopy (SEM) include air drying, hexamethyldisilazane (HMDS) or tetramethysilane (TMS) treatment and critical point drying (CPD). On the other side, freeze-drying has been widely employed in dehydrating biological samples and also in preparing porous biomaterial scaffolds but not in preparing cells on three-dimensional (3D) biomaterials for SEM examination. In this study, we compare cells on porous hydroxyapatite (HA) prepared by air drying, HMDS and freeze-drying. The effects of fixation and using phosphate buffered saline (PBS) in the fixation were also assessed on three porous calcium phosphate (CaP) materials, namely, HA, ?-tricalcium phosphate (?-TCP) and ?-tricalcium phosphate (?-TCP) samples. There is no significant difference in samples prepared by HMDS treatment and freeze-drying viewed at low magnification. Besides, it is better not to use phosphate buffer in the fixation step for CaP materials to avoid undesirable spontaneous precipitation of CaPs. On the other hand, fewer exchanges of liquids are required for freeze-drying and hence chemical fixation may not be absolutely required for samples prepared by freeze-drying. Other technical details of the preparation were also investigated and discussed. This study suggests both HMDS and freeze-drying can be employed to dehydrate cells on 3D scaffolds for SEM examination. PMID:22532079

Lee, Juliana Tsz Yan; Chow, King Lau

2011-08-24

304

Accurate freezing and melting equations for the Lennard-Jones system  

NASA Astrophysics Data System (ADS)

Analyzing three approximate methods to locate liquid-solid coexistence in simple systems, an observation is made that all of them predict the same functional dependence of the temperature on density at freezing and melting of the conventional Lennard-Jones (LJ) system. The emerging equations can be written as T=?4+?2 in normalized units. We suggest to determine the values of the coefficients at freezing and melting from the high-temperature limit, governed by the inverse 12th power repulsive potential. The coefficients can be determined from the triple point parameters of the LJ fluid. This produces freezing and melting equations which are exact in the high-temperature limit and at the triple point and show remarkably good agreement with numerical simulation data in the intermediate region.

Khrapak, Sergey A.; Morfill, Gregor E.

2011-03-01

305

Managing your depression - teens  

MedlinePLUS

Recognizing depression in your teen; Helping your teen with depression ... treatment for major depressive disorder in children and adolescents: US Preventive Services Task Force Recommendation Statement. Pediatrics . ...

306

Linking Depressed Earnings to Adolescent Depression  

Microsoft Academic Search

In this study, I analyze empirically the ways in which adolescent depression depresses earnings in young adulthood. I test the prominent assertions that adolescent depression is predictive of young adult depression and of lower educational attainment, both of which are, in turn, predictive of lower earnings. I then expand upon the current literature by testing the assumption that those depressed

Emily Sands

2008-01-01

307

Salt Water Desalination by the Freezing Method.  

National Technical Information Service (NTIS)

Investigations of the most important units of the new method of salt water desalination by artificial freezing with the help of liquid hydrocarbons (propane-butane mixture) were conducted. Investigation of contact heat transfer processes indicates that th...

I. M. Rutgaizer S. Seitkurbanov V. I. Petrov

1969-01-01

308

Cell-encapsulating droplet formation and freezing  

NASA Astrophysics Data System (ADS)

Cell-encapsulating droplets are vitrified for biopreservation applications. The dynamics of micro-droplet formation and its freezing mechanism are analyzed numerically and experimentally. In addition, the microdroplet encapsulation technique is applied to cryopreserve cells.

Ryoun Youn, Jae; Seok Song, Young

2012-09-01

309

Freeze-out Conditions from Lattice QCD  

NASA Astrophysics Data System (ADS)

We describe a procedure for determination of freeze-out parameters of heavy-ion collisions through direct comparisons between experimentally measured higher order cumulants of charge fluctuations and first principle (lattice) QCD calculations.

Mukherjee, Swagato

2013-05-01

310

Evaporation of water from agitated freezing slurries at low pressure  

Microsoft Academic Search

In an absorptive vacuum freezing process, water evaporates from the freezing solution and condenses on a cold salt solution. Given sufficient condensing capacity, the evaporation rate will be controlled by the freezing solution vapor pressure. The size of the condensing equipment which matches a given evaporation system can be estimated using rate measurements made with low vapor pressure freezing solutions.

L. C. Dickey

1996-01-01

311

Freeze Drying of Foods for the Armed Services.  

National Technical Information Service (NTIS)

The report reviews the development and use of freeze-dried food products for the Armed Services. It covers the various products and ration systems that have been developed, the basic parameters of freeze-drying and freeze-dried foods, commercial freeze-dr...

J. M. Tuomy

1971-01-01

312

A climatological study of surface freezing precipitation in Europe  

Microsoft Academic Search

A climatological study of the occurrence of freezing precipitation at ground level is presented. It is based on reports of freezing precipitation in SYNOP messages from the three winters covering the years 1995-1998. The geographical domain covered is Western and Central Europe, extending northwards to Scandinavia and southwards to North Africa. The types of freezing precipitation selected are freezing rain,

Jean-Marie Carrière; Claude Lainard; Christine Le Bot; Florent Robart

2000-01-01

313

Freezing Tolerance in an Adult Insect  

Microsoft Academic Search

The adult carabid beetle Pterostichus brevicornis tolerates freezing under natural conditions. Laboratory tests confirm that winter beetles tolerate temperatures below -35 degrees C, whereas summer beetles die if frozen at -6.6 degrees C. Winter beetles can be cooled to about -10 degrees C before freezing, and they thaw near -3.5 degrees C. Summer beetles thaw at -0.7 degrees C. To

L. Keith Miller

1969-01-01

314

An inherently freeze protected solar water heater  

SciTech Connect

A solar water heater which uses a roof-contained solar absorber operating a two-phase thermosiphon with splash heat exchanger is described. Such a thermosiphon has operating characteristics which may be exploited to achieve simple and reliable freeze protection. An installation is described and the physical arrangements needed to obtain freeze protection are discussed. The results of a number of tests are presented.

Rush, C.K.

1983-06-01

315

Passive freeze protection for solar collectors  

Microsoft Academic Search

Freeze damage is an important practical problem for water-type solar collectors. In the past, electric resistance heaters, drain systems, and separate ethylene glycol-water collection loops have commonly been used to prevent freezing. These techniques are effective but involve active components such as controls, heaters, valves, solenoids, pumps, heat exchangers, etc., that increase costs, degrade reliability and\\/or reduce overall efficiency. This

L. W. Bickle

1975-01-01

316

Preservation of surface lipids and determination of ultrastructure of Mycobacterium kansasii by freeze-substitution.  

PubMed Central

The cell wall architecture of a slowly growing mycobacterium, Mycobacterium kansasii, was examined by freeze-substitution following growth in vitro. Freeze-substituted bacteria were marked by the presence of an electron-translucent space (or electron-transparent zone [ETZ] described by previous workers [T. Yamamoto, M. Nishiura, N. Harada, and T. Imaeda, Int. J. Lepr. 26:111-114, 1958]) surrounding the majority of cells. At least two morphotypes of mycobacteria were revealed by freeze-substitution. In the first, a relatively thin (11 +/- 2.3 to 3.5 +/- 3.1 nm), uniform ETZ surrounded intact cells which contained cytoplasm filled with well-stained ribosomes and a DNA nucleoid distributed throughout the cell. The second morphotype consisted of a small proportion of organisms that were distorted in shape and were surrounded by a much thicker (59 +/- 2.6 to 198 +/- 2.5 nm) ETZ in areas of the cell which appeared to have retracted from the space it had originally occupied, leaving depressions in the ETZ. The lipid nature of the ETZ was demonstrated because cells were devoid of an ETZ when organisms were freeze-substituted in the absence of osmium tetroxide in the substitution medium or treated with neutral lipid solvents (acetone or ethanol) before freeze-substitution. Moreover, thin-layer chromatography of acetone or ethanol extracts obtained from solvent-treated cells identified a lipid component which corresponded to the M. kansasii-specific phenolic glycolipid. In contrast, negligible amounts of glycolipids were detected in extracts obtained from control HEPES (N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid) buffer-treated cells, and these cells retained an ETZ. These results demonstrate that species-specific phenolic glycolipids are essential components in the architecture of the M. kansasii ETZ. Furthermore, we show that freeze-substitution is a reliable technique for the retention and precise preservation of lipid-containing polymers in the mycobacterial cell wall. Images

Paul, T R; Beveridge, T J

1994-01-01

317

Historical recollections of freeze-drying.  

PubMed

The history of freeze-drying is surprisingly recent. Although Altmann used freeze-drying for the preparation of histological sections as early as 1890, his technique went unnoticed for over 40 years. Shackell independently rediscovered the technique in 1909 for the preservation of biologicals. The industrial applications of freeze-drying do not appear to have been appreciated prior to the patients of Tival in 1927 and Elser in 1934, rapidly followed by the important contributions of Flosdorf in the United States and Greaves in England who were largely responsible for making large scale applications of freeze-drying possible. Stimulated particularly by a series of symposia in England and the United States and the renowned courses on freeze-drying organized by Rey in France, the atmosphere in the 1950s and early 60s was one of optimism for the future of freeze-drying, particularly in its application to food stuffs. Many of the dreams of that time remain unfulfilled, largely because of the higher costs of quality processing. Nevertheless, although the optimism may have somewhat dimmed, the promise remains, and economic changes in the future may well stimulate another surge in development. PMID:801137

Meryman, H T

1976-10-01

318

Freezing of living cells: mechanisms and implications  

SciTech Connect

Cells can endure storage at low temperatures such as -196/sup 0/C for centuries. The challenge is to determine how they can survive both the cooling to such temperatures and the subsequent return to physiological conditions. A major factor is whether they freeze intracellularly. They do so if cooling is too rapid, because with rapid cooling insufficient cell water is removed osmotically to eliminate supercooling. Equations have been developed that describe the kinetics of this water loss and permit one to predict the likelihood of intracellular freezing as a function of cooling rate. Such predictions agree well with observations. Although the avoidance of intracellular freezing is usually necessary for survival, it is not sufficient. Slow freezing itself can be injurious. As ice forms outside the cell, the residual unfrozen medium forms channels of decreasing size and increasing solute concentration. The cells lie in the channels and shrink in osmotic response to the rising solute concentration. Prior theories have ascribed slow freezing injury to the concentration of solutes or the cell shrinkage. Recent experiments, however, indicate that the damage is due more to the decrease in the size of the unfrozen channels. This new view of the mechanism of slow freezing injury ought to facilitate the development of procedures for the preservation of complex assemblages of cells of biological, medical, and agricultural significance. 126 references, 18 figures, 2 tables.

Mazur, P.

1984-01-01

319

Diagnosing depression  

PubMed Central

OBJECTIVE To explore and describe primary care physicians’ experiences in providing care to depressed patients and to increase understanding of the possibilities and constraints around diagnosing and treating depression in primary care. DESIGN Qualitative study using personal interviews. SETTING A hospital region in eastern Canada. PARTICIPANTS A purposely diverse sample of 20 physicians chosen from among all 100 practising family physicians in the region. METHOD Invitations were mailed to all physicians practising in the region. Twenty physicians were chosen from among the 39 physicians responding positively to the invitation. Location of practice, sex, and year of graduation from medical school were used as sampling criteria. The 20 physicians were then interviewed, and the interviews were audiotaped and transcribed verbatim. Data were analyzed using a constant comparative approach involving handwritten notes on transcripts and themes created using qualitative data analysis software. MAIN FINDINGS Three themes related to diagnosis emerged. The first concerns use of checklists. Physicians said they needed an efficient but effective means of diagnosing depression and often used diagnostic aids, such as checklists. Some physicians, however, were reluctant to use such aids. The second theme, interpersonal processes, involved the investment of time needed for diagnosing depression and the importance of establishing rapport. The final theme, intuition, revealed how some physicians relied on “gut sense” and years of experience to make a diagnosis. CONCLUSION Diagnosis of depression by primary care physicians involves a series of often complicated negotiations with patients. Such negotiations require expertise gained through experience, yet prior research has not recognized the intricacies of this diagnostic process. Our findings suggest that future research must recognize the complex and multidisciplinary nature of physicians’ approaches to diagnosis of depression in order to better reflect how they practise.

Thomas-MacLean, Roanne; Stoppard, Janet; Miedema, Baukje (Bo); Tatemichi, Sue

2005-01-01

320

Measuring Symptoms of Depression  

PubMed Central

The purpose of this study was to extend available psychometric data on the Patient Health Questionnaire-9-Observation Version (PHQ-9-OV) by comparing it with the Cornell Scale for Depression in Dementia (CSDD) in a new sample of long-term care residents. Data were collected post intervention in a quasi-experimental storytelling study across six communities. The sample (N = 54) was 87% women with mean age of 84.5, mean CSDD score of 3.96, and mean PHQ-9-OV score of 4.22. Prevalence of depressive symptoms by CSDD criteria was 20.4% and by PHQ-9-OV criteria was 40.7%. The CSDD and PHQ-9-OV were well correlated (rs = 0.78, p < 0.0001). Neither scale was significantly correlated with depression diagnosis nor antidepressant agent use. Both measures demonstrated adequate reliability. The PHQ-9-OV item scoring and established cut-off points designate a lower threshold than the CSDD to detect clinically significant depressive symptoms. Further study is needed to determine the sensitivity of the PHQ-9-OV in identifying treatment effects.

Phillips, Lorraine J.

2012-01-01

321

Depression and Smoking  

MedlinePLUS

Home » Tools » Depression Basics » Depression and Smoking Depression and Smoking How is depression different from withdrawal from smoking? Mood changes are common after quitting smoking. You might be irritable, restless, or ...

322

Depression and the hyperactive right-hemisphere  

Microsoft Academic Search

Depression is associated with an inter-hemispheric imbalance; a hyperactive right-hemisphere (RH) and a relatively hypoactive left-hemisphere (LH). Nevertheless, the underlying mechanisms which can explain why depression is associated with a RH dominance remain elusive. This article points out the potential links between functional cerebral asymmetries and specific symptoms and features of depression. There is evidence that the RH is selectively

David Hecht

2010-01-01

323

A new freeze casting technique for ceramics  

NASA Astrophysics Data System (ADS)

A new freeze casting technique for ceramics capable of manufacturing near room temperature with a sublimable vehicle has been developed in order to eliminate expensive processes under extremely cold temperatures in the conventional freeze casting. Fluid concentrated slurries of Al2O 3 powder in molten camphene (C10H16) were successfully prepared at 55°C with a small amount of a dispersant. These slurries were quickly solidified (frozen) at room temperature to yield a rigid solid green body, where the frozen camphene was easily removed by sublimation (freeze-drying) with negligible shrinkage. Sintering was successfully conducted without any special binder burnout process to yield dense sintered bodies (over 98% T.D). An organic alloy with a eutectic composition in the naphthalene (C 10H8)-camphor (C10H16O) binary system with a eutectic temperature of 31°C was also found to be a successful vehicle for the new ceramic freeze casting. The fabrication processes are almost the same as those with camphene. It was found that vehicles with off-eutectic compositions resulted in large voids in the sintered body due to the ceramic particle rejection by pro-eutectic crystals during freezing. At the eutectic composition, fine lamellar microstructure in the solidified vehicle inhibits the particle rejection. The proposed advantages of the new freeze casting technique with a sublimable vehicle include; (1) elimination of extremely cold temperatures used in conventional freeze casting; (2) elimination of troublesome binder burnout process; and (3) fast manufacturing cycle due to quick solidification. Porous ceramic bodies with unique interconnected pore channels were fabricated by the new freeze casting with lower solid content. The unique channels surrounded by fully dense walls have nearly circular cross-sections unlike conventional aqueous freeze casting. The porosity and the channel diameters are controllable by the solid content in the slurry. The unique channels are replicas of entangled dendrites of frozen camphene, which sublimes during freeze-drying process. The unique porous structure with interconnected pore channels, which is completely new, is considered potentially useful in many applications such as filters and implantable bone scaffolds.

Araki, Kiyoshi

324

Contrasting effects of high-pressure-assisted freezing and conventional air-freezing on eggplant tissue microstructure  

Microsoft Academic Search

Damage to the microstructure of eggplants frozen by conventional air-freezing methods and by a high-pressure-assisted freezing\\u000a method is compared in this paper. When conventional air-freezing techniques are employed, damage to the microstructure is\\u000a enhanced as the freezing rate diminishes and the sample volume increases. However, when high-pressure-assisted freezing is\\u000a applied, bulk nucleation occurs simultaneously in the whole sample, and the

Laura Otero; María T. Solas; P. D. Sanz; Carlos de Elvira; Juan A. Carrasco

1998-01-01

325

Genetics of smoking and depression.  

PubMed

Smoking and depression are significant public health problems with multiple etiological dimensions and outcomes. Although each condition is important by itself, they are important because they often potentiate each other. Consequently, it is also essential to understand the nature their relationship. This representative review focuses on the genetic etiology of the relationship in the context of reviewing first the epidemiology of depression and smoking, and then by exploring behavioral and molecular genetic studies, and other psychiatric and medical comorbidities. At this point, epidemiological evidence for a relationship between depression and smoking/nicotine dependence is compelling. Although behavioral genetic results differ somewhat by gender and in accordance with specific definitions of depression and smoking variables, recent studies show converging evidence for common genetic factors underlying the relationship, often in addition to non-shared environmental factors. The search for underlying genes and genetic mechanisms is at an early stage, but shows promising candidate genes and genetic approaches for future studies. PMID:22526528

Tsuang, Ming T; Francis, Tracee; Minor, Kyle; Thomas, Alison; Stone, William S

2012-04-17

326

Prenatal paternal depression.  

PubMed

Prenatal depressive symptoms, anxiety, anger and daily hassles were investigated in 156 depressed and non-depressed pregnant women and their depressed and non-depressed partners (fathers-to-be). Depressed versus non-depressed fathers had higher depression, anxiety and daily hassles scores. Although the pregnant women in general had lower anxiety, anger and daily hassles scores than the men, the scores on the measures for depressed fathers and depressed mothers did not differ. Paternal depression appeared to have less effect than maternal depression on their partners' scores. However, the similarity between the scores of depressed mothers and depressed fathers highlights the importance of screening for depression in fathers-to-be as well as mothers-to-be during pregnancy. PMID:17138311

Field, Tiffany; Diego, Miguel; Hernandez-Reif, Maria; Figueiredo, Barbara; Deeds, Osvelia; Contogeorgos, Jennifer; Ascencio, Angela

2006-11-13

327

Prenatal Paternal Depression  

PubMed Central

Prenatal depressive symptoms, anxiety, anger and daily hassles were investigated in 156 depressed and non-depressed pregnant women and their depressed and non-depressed partners (fathers-to-be). Depressed versus non-depressed fathers had higher depression, anxiety and daily hassles scores. Although the pregnant women in general had lower anxiety, anger and daily hassles scores than the men, the scores on the measures for depressed fathers and depressed mothers did not differ. Paternal depression appeared to have less effect than maternal depression on their partners’ scores. However, the similarity between the scores of depressed mothers and depressed fathers highlights the importance of screening for depression in fathers-to-be as well as mothers-to-be as well as during pregnancy.

Field, Tiffany; Diego, Miguel; Hernandez-Reif, Maria; Figueiredo, Barbara; Deeds, Osvelia; Contogeorgos, Jennifer; Ascencio, Angela

2007-01-01

328

Influence of freezing rate on pore structure in freeze-dried collagen-GAG scaffolds  

Microsoft Academic Search

The cellular structure of collagen-glycosaminoglycan (CG) scaffolds used in tissue engineering must be designed to meet a number of constraints with respect to biocompatibility, degradability, pore size, pore structure, and specific surface area. The conventional freeze-drying process for fabricating CG scaffolds creates variable cooling rates throughout the scaffold during freezing, producing a heterogeneous matrix pore structure with a large variation

Fergal J. O’Brien; Brendan A. Harley; Ioannis V. Yannas; Lorna J Gibson

2004-01-01

329

Intracellular freezing and survival in the freeze tolerant alpine cockroach Celatoblatta quinquemaculata  

Microsoft Academic Search

The alpine cockroach Celatoblatta quinquemaculata is common at altitudes of around 1500 m on the Rock and Pillar range of Central Otago, New Zealand where it experiences freezing conditions in the winter. The cockroach is freeze tolerant, but only to c. ?9 °C. The cause of death at temperatures below this is unknown but likely to be due to osmotic

M. R. Worland; D. A. Wharton; S. G. Byars

2004-01-01

330

The hyphae of Uromyces appendiculatus within the leaf tissue after high pressure freezing and freeze substitution  

Microsoft Academic Search

Summary The fine structure of the intercellular dikaryotic hyphae of the biotrophic fungusUromyces appendiculatus was studied. High pressure freezing and freeze substitution were used to achieve a closer approximation of the native state than with conventional fixation and dehydration techniques. In addition to organelles previously described in rust fungi, heavily decorated multivesicular bodies (star bodies) were found close to the

K. Welter; M. Müller; K. Mendgen

1988-01-01

331

IDENTIFICATION OF METABOLITES ASSOCIATED WITH FREEZING TOLERANCE IN CONSTITUTIVELY FREEZING TOLERANT MUTANTS OF ARABIDOPSIS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Many plants develop a better freezing tolerance through a process of cold acclimation (CA), which also results in many changes in metabolite levels. To identify and distinguish metabolites that contribute to the increased freezing tolerance from those that are merely responsive to low temperature st...

332

Predicting Arabidopsis Freezing Tolerance and Heterosis in Freezing Tolerance from Metabolite Composition  

PubMed Central

Heterosis, or hybrid vigor, is one of the most important tools in plant breeding and has previously been demonstrated for plant freezing tolerance. Freezing tolerance is an important trait because it can limit the geographical distribution of plants and their agricultural yield. Plants from temperate climates increase in freezing tolerance during exposure to low, non-freezing temperatures in a process termed ‘cold acclimation’. Metabolite profiling has indicated a major reprogramming of plant metabolism in the cold, but it has remained unclear in previous studies which of these changes are related to freezing tolerance. In the present study, we have used metabolic profiling to discover combinations of metabolites that predict freezing tolerance and its heterosis in Arabidopsis thaliana. We identified compatible solutes and, in particular, the pathway leading to raffinose as crucial statistical predictors for freezing tolerance and its heterosis, while some TCA cycle intermediates contribute only to predicting the heterotic phenotype. This indicates coordinate links between heterosis and metabolic pathways, suggesting that a limited number of regulatory genes may determine the extent of heterosis in this complex trait. In addition, several unidentified metabolites strongly contributed to the prediction of both freezing tolerance and its heterosis and we present an exemplary analysis of one of these, identifying it as a hexose conjugate.

Korn, Marina; Gartner, Tanja; Erban, Alexander; Kopka, Joachim; Selbig, Joachim; Hincha, Dirk K.

2010-01-01

333

Cryoprotectants for freeze drying of drug nano-suspensions: effect of freezing rate.  

PubMed

Drug nanoparticles are often prepared in a liquid medium, and a drying method such as freeze drying is used to convert them to an oral solid dosage form. When the dried form is reconstituted in an aqueous system, it may be redispersed to achieve its original particle size. The redispersibility of dried nanoparticles depends on the parameters of the freeze drying process. In this study, an apparatus with a freezing rate gradient was used to systematically investigate the effect of cryoprotectants on the redispersibility of nanoparticles as a function of freezing rate. Sucrose, lactose, mannitol, and polyethylene glycol were used as cryoprotectants for a naproxen nano-suspension. A fast freezing rate and a high cryoprotectant concentration were generally favored. However, under certain conditions, a slower freezing rate resulted in better redispersibility. This is probably because slow freezing can produce a more cryo-concentrated liquid phase, and the concentrated cryoprotectant in the liquid phase can more effectively protect the nanoparticles. An irreversible aggregation map was constructed as a function of the freezing rate and the cryoprotectant concentration, and shows both the favorable and unfavorable effects of cryoprotectants. PMID:19475555

Lee, Min Kyung; Kim, Min Young; Kim, Sujung; Lee, Jonghwi

2009-12-01

334

The equilibrated state of freezing as a basis for distinguishing lethal stresses of freezing in plants  

Technology Transfer Automated Retrieval System (TEKTRAN)

A model for coordination of stresses that limit winterhardiness in plants based on the thermodynamic equilibrated state of freezing and melting provides a rational basis for distinction of freeze-induced energies which can stress and injure living organisms in various ways. The departure from equili...

335

Representative Values of Icing-Related Variables Aloft in Freezing Rain and Freezing Drizzle  

Microsoft Academic Search

Radiosonde and surface observations in freezing rain (ZR) and freezing drizzle (ZL), and a limited number of aircraftmeasurements in ZR, have been examined for information on the magnitude and altitude dependence of meteorological variablesassociated with aircraft icing in these conditions. The variables include temperature aloft, humidity (clouds), and windshear fromthe radiosondes; surface temperatures, ceiling heights, precipitation type and amount from

Richard K. Jeck

336

Depressed Mood in Adolescence: Who Goes Unnoticed?  

ERIC Educational Resources Information Center

|Depression in adolescence typically has a debilitating toll in terms of academic and social functioning, and it predicts a variety of negative outcomes later. Previous research points out that once on a depressed trajectory in development, an individual becomes more likely to stay on this course because of the tendency to both alienate and…

Watson, Cary M.; Quatman, Teri; Swanson, Connie

337

Impurity and thermal modelling of SPRT fixed-points  

NASA Astrophysics Data System (ADS)

Impurities in pure metal fixed points for the calibration of standard platinum resistance thermometers (SPRTs) causes significant variations in the freezing temperature, of the order of sub-mK to several mK. This often represents the largest contribution to the overall uncertainty of the fixed point temperature, and it is therefore of great interest to explore ways of correcting for this effect. The sum of individual estimates (SIE) method, in which the contributions of all the impurities are summed, is the recommended way of determining the correction if one has an accurate knowledge of the impurities present and their low concentration liquidus slopes. However, due to the difficulty in obtaining reliable iningot impurity corrections, it remains useful to investigate the influence of impurities on freezing curves using modeling techniques, and ultimately to parameterize the freezing curve by e.g. least-squares fitting to make corrections to the temperature of the freeze. Some success in analyzing freezing curves has been achieved. When parameterizing experimentally determined freezing curves, it is necessary to reliably determine the freezing end-point, and minimize spurious thermal effects. We outline some methods for meeting these requirements. As the influence of impurities is always convolved with thermal influences it is instructive to construct a model which takes into account both heat and impurity transport. We describe the development of more sophisticated models which take both these effects into account.

Pearce, J. V.; Veltcheva, R. I.; Large, M. J.

2013-09-01

338

Natural freezing as a wastewater treatment method: E. coli inactivation capacity  

Microsoft Academic Search

Inactivation capacity of E. coli (strain ATCC 15597) in water by natural freezing was examined via two freezing methods: spray freezing and freezing in a freezer. The effect of freezing temperature (?5, ?15 and ?35°C), storage time, freeze–thaw cycles on the survival of the test organism were investigated. In addition, the number of cells injured by the freezing process was

W. Gao; D. W. Smith; Y. Li

2006-01-01

339

Cell cycle regulation in the freeze tolerant wood frog, Rana sylvatica.  

PubMed

The wood frog (Rana sylvatica) is one of only a few vertebrate species that can survive extensive freezing of its body fluids during the winter. The mechanisms of natural freeze tolerance include metabolic rate depression to conserve energy and the implementation of cryoprotective strategies, especially the synthesis of huge amounts of glucose as a cryoprotectant. Liver is the main source of glucose production/export (and other cryoprotective actions) and plays a central role in freezing survival of the whole animal. Freezing is a multi-component stress that includes anoxia/ischemia due to the cessation of blood flow and dehydration of cells caused by ice accumulation in extracellular spaces. To help endure these stresses, cells need to suppress and reprioritize ATP-expensive cell functions. One of these is cell growth and proliferation, and we hypothesized that cell cycle arrest would be key to freezing survival. The present study examines the responses by key cell cycle components to freezing, anoxia and dehydration stresses in wood frog liver. Immunoblotting was used to investigate protein expression of Cdc 2, Cdks (2, 4, 6), and cyclins (A, B1, D1, E) as well as the phosphorylation states of Cdks (Thr14/Tyr15), the phosphatases Cdc25a (Ser76) and Cdc25c (Ser216) and the CIP/KIP Cdk inhibitors p21 (Thr145) and p27 (Thr187). Responses to 24 h freezing, 24 h anoxia and 40% dehydration as well as recovery from these stresses were analyzed. The results showed very similar responses by cell cycle components to anoxia or dehydration and were consistent with cell cycle suppression under stress and reversal during recovery. Freezing showed elements of cell cycle suppression, including reduced protein levels of Cdks and cyclins A and B1, but also showed unique responses by cyclin D1, Cdc25 phosphatases and p21/p27. These may be linked with alternative actions by these proteins that contribute to cryoprotection; e.g., an alternative action of cyclin D1 as a transcription factor may contribute to the upregulation of glucose-6-phosphatase, a key enzyme needed for the export of glucose cryoprotectant. PMID:22510573

Zhang, Jing; Storey, Kenneth B

2012-05-01

340

Freezing-thawing action in the deterioration of the stones of Chambord Castle  

NASA Astrophysics Data System (ADS)

Limestone is very common in architecture (monuments and cultural heritage buildings) and used in the sculptures. The soft and porous limestone soaks up water and show weathering patterns and forms: alveolar weathering, granular disintegration, efflorescences. Freezing-thawing actions can be considered as one of the processes that contribute in the deterioration of stones located in the "cold regions" characterized with air temperatures below freezing point temperature. The amount of water within the pore space of the stones is a crucial factor of the decay. The experimental work presented in this paper is a part of a research program that aims to study the mechanisms that lead to the degradation of stone building materials due to the variation of climatic conditions. The analysis of the meteorological data of the field around the castle of Chambord shows the magnitude of temperature variations and the frequency of freezing-thawing cycles. The critical degrees of saturation at which the stone start to deteriorate after treatment with freezing-thawing cycles were examined in the tests conducted. The study concerns two porous limestone used in the construction and conservation of Chambord castle; highly porous Tuffeau stone having a total porosity of about 48 %, and medium porous Richemont stone with a total porosity of 27 %. Richemont stone has been used as a substitute stone of the degraded Tuffeau stone on the castle. The main physical properties, total porosity, apparent dry density and skeleton density and sound velocity for mechanical properties were measured for the stone samples before and during freezing-thawing cycles. ASTM (D5312-04) procedure was applied in the freezing-thawing tests. Tuffeau and Richmond samples were prepared at nine different degrees of saturations; 0, 20, 40, 70, 80, 85, 90, 95 and 100%, and properties were measured after different freezing-thawing cycles conditions; 2, 4, 8, 12, 16, 20, 30 and 50 cycles. The results of these tests show that when the degree of saturation exceeds 80-85%, freeze-thaw damage is inevitable even for a very few freeze-thaw cycles. Moreover, results indicate that the two studied stones have similar critical degree of saturation of about 85 %. This can be attributed to the similar percentage of macro-pores in the two tested stones. Finally, the critical degree of saturation was not changed after increasing the number of freezing-thawing cycles, thus the critical degree of saturation can be considered as a stone property.

Alomari, Asaad; Brunetaud, Xavier; Beck, Kevin; Al-Mukhtar, Muzahim

2013-04-01

341

Freeze-out Coupling in Hydrodynamics.  

NASA Astrophysics Data System (ADS)

Most hydrodynamical calculations used in heavy-ion physics ignore the effect of freeze-out matter carrying energy and momentum away from the expanding fluid. In a simple one-dimensional model we compare calculated energy density and velocity profiles, with and without interaction between fluid-like and freeze-out parts of the system, in order to estimate the importance of this effect. We use an extended version of the Godunov method( J.-P. Blaizot and J.-Y. Ollitrault, Nucl. Phys.) A458 (1986) 745. to describe the hydrodynamical evolution with freeze-out coupling. It is found that the feedback from freeze-out can have substantial effects on the evolution of the freeze-out surface. The coupling should therefore be taken into account in the next generation of hydrodynamical calculations. Preliminary version available from the LANL archive, nucl- th/9612020.

Lavrenchuk, Boris; Neumann, John J.; Fai, George

1997-04-01

342

Demulsification of oil-in-water emulsion under freezing conditions: Effect of crystal structure modifier  

Microsoft Academic Search

The demulsification of oil-in-water (O\\/W) emulsions under freezing conditions is connected to fat crystallization in the oil\\u000a droplet. Therefore, demulsification can be prevented by the use of oil with a low melting point, and also by lowering the\\u000a O\\/W ratio. However, an oil with a low melting point, such as sunflower, is rather expensive, and the O\\/W ratio has a

Takuya Harada; Kazuhisa Yokomizo

2000-01-01

343

Freeze-fracture studies of myofiber plasma membrane in X chromosome-linked muscular dystrophy (mdx) mice  

Microsoft Academic Search

The structure of the muscle plasma membrane of extensor digitorum longus muscles of X chromosome-linked muscular dystrophy (mdx) mice was studied by freeze-fracture technique at several time points after birth. The common denominator of the abnormalities was the decreased density of orthogonal arrays throughout all the time points examined. The results demonstrated that the ultrastructural features of the muscle plasma

S. Shibuya; Y. Wakayama

1988-01-01

344

Soil salinity increases survival of freezing in the enchytraeid Enchytraeus albidus.  

PubMed

Enchytraeus albidus is a freeze-tolerant enchytraeid found in diverse habitats, ranging from supralittoral to terrestrial and spanning temperate to arctic regions. Its freeze tolerance is well known but the effect of salinity in this strategy is still poorly understood. We therefore studied the combined effect of salinity (0, 15, 35, 50‰ NaCl) and sub-zero temperatures (-5, -14, -20°C) on the freeze tolerance of E. albidus collected from two distinct geographical regions (Greenland and Germany). A full factorial design was used to study survival, and physiological and biochemical end points. The effect of salinity on the reproduction of German E. albidus was also assessed. Exposure for 48 h to saline soils prior to cold exposure triggered an increase in osmolality and decrease in water content. Worms exposed to saline soils had an improved survival of freezing compared to worms frozen in non-saline soils, particularly at -20°C (survival more than doubled). Differential scanning calorimetry measurements showed that the fraction of water frozen at -5 and -14°C was lower in worms exposed to 35‰ NaCl than in control worms. The lowering of ice content by exposure to saline soils was probably the main explanation for the better freeze survival in saline-exposed worms. Glucose increased with decreasing temperature, but was lower in saline than in non-saline soils. Thus, glucose accumulation patterns did not explain differences in freeze survival. Overall, the physiological responses to freezing of E. albidus from Greenland and Germany were similar after exposure to saline soils. Soil salinity up to 30‰ improved reproduction by a factor of ca. 10. PMID:23531829

Silva, A L Patrício; Holmstrup, M; Kostal, V; Amorim, M J B

2013-03-26

345

Altered BDNF and Dopamine Levels In Depression  

NSDL National Science Digital Library

Doctor Abraham Zangen point out that dopamine and BDNF levels in the nucleus accumbens and hippocampus of depressed patients are different. Treatment with antidepressants or ECT can impact these differences.

2009-12-26

346

Kinetics of Water Loss from Cells at Subzero Temperatures and the Likelihood of Intracellular Freezing  

PubMed Central

The survival of various cells subjected to low temperature exposure is higher when they are cooled slowly. This increase is consistent with the view that slow cooling decreases the probability of intracellular freezing by permitting water to leave the cell rapidly enough to keep the protoplasm at its freezing point. The present study derives a quantitative relation between the amount of water in a cell and temperature. The relation is a differential equation involving cooling rate, surface-volume ratio, membrane permeability to water, and the temperature coefficient of the permeability constant. Numerical solutions to this equation give calculated water contents which permit predictions as to the likelihood of intracellular ice formation. Both the calculated water contents and the predictions on internal freezing are consistent with the experimental observations of several investigators.

Mazur, Peter

1963-01-01

347

The GABAergic deficit hypothesis of major depressive disorder  

Microsoft Academic Search

Increasing evidence points to an association between major depressive disorders (MDDs) and diverse types of GABAergic deficits. In this review, we summarize clinical and preclinical evidence supporting a central and causal role of GABAergic deficits in the etiology of depressive disorders. Studies of depressed patients indicate that MDDs are accompanied by reduced brain concentration of the inhibitory neurotransmitter ?-aminobutyric acid

B Luscher; Q Shen; N Sahir

2011-01-01

348

Heat transfer coefficient of cryotop during freezing.  

PubMed

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). PMID:23812315

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

2013-01-01

349

Freeze verification: time for a fresh approach  

SciTech Connect

The administration's claim that some elements of a comprehensive nuclear freeze are unverifiable does not specify the nature of those elements and whether they represent a real threat to national security if we trusted the USSR to comply. The author contends that clandestine development of new weapons will have little strategic effect since both sides already have total destructive power. The risks of noncompliance are largely political and less than the risks of continued arms buildup. Since the USSR would also want the US to be bound by freeze terms, deterrence would come from mutual benefit. Hardliners argue that cheating is easier in a closed society; that our democracy would tend to relax and the USSR would move ahead with its plans for world domination. The author argues that, over time, a freeze would diminish Soviet confidence in its nuclear war fighting capabilities and that adequate verification is possible with monitoring and warning arrangements. (DCK)

Paine, C.

1983-01-01

350

Postnatal depression  

PubMed Central

Introduction The differentiation between postnatal depression and other types of depression is often unclear, but there are treatment issues in nursing mothers that do not apply in other situations. Overall, the prevalence of depression in postpartum women is the same as the prevalence in women generally, at about 12–13%. Suicide is a major cause of maternal mortality in resource-rich countries, but rates are lower in women postpartum than in women who have not had a baby. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of drug treatments, and of non-drug treatments, for postnatal depression? We searched: Medline, Embase, The Cochrane Library, and other important databases up to May 2008 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 34 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: group cognitive behavioural therapy, hormones, individual cognitive behavioural therapy (CBT), infant massage by mother, interpersonal psychotherapy, light therapy, mother–infant interaction coaching, non-directive counselling, other antidepressants, physical exercise, psychodynamic therapy, psychoeducation with partner, selective serotonin reuptake inhibitors (SSRIs), St John’s Wort, telephone-based peer support.

2009-01-01

351

Protein spray freeze drying. 2. Effect of formulation variables on particle size and stability.  

PubMed

Spray freeze drying produces protein particles suitable for microencapsulation into polymeric microspheres intended for sustained release. Accessibility of encapsulated protein particles to the microsphere surface increases as the protein particle size is increased. Thus, it is desirable that the encapsulated protein particle size be minimized to limit initial release. We have investigated the effect of formulation on spray freeze-dried bovine serum albumin (BSA) as a model protein. Atomization conditions were fixed such that in the absence of excipient, the particle size of the sonicated powder was submicron, and there was substantial protein degradation (loss of monomer). Addition of low concentrations of surfactants (up to the CMC) or mannitol (up to the point where it tended to crystallize upon dehydration) resulted in partial stabilization without impacting particle size. Trehalose was successful in stabilizing the protein; however, there was a marked increase in particle size at the highest levels tested. Ammonium sulfate provided partial stabilization, but also tended to form crystals and increase particle size. FTIR measurements showed a loss of native secondary structure upon spray freeze drying that was ameliorated by addition of trehalose. Other excipients did not prevent structural perturbations. In general, stabilization of spray freeze-dried BSA was related to lowering of the specific surface area in the powder. A balance must be achieved when spray freeze drying proteins intended for encapsulation in sustained-release systems. PMID:11835198

Costantino, Henry R; Firouzabadian, Laleh; Wu, Chichih; Carrasquillo, Karen G; Griebenow, Kai; Zale, Stephen E; Tracy, Mark A

2002-02-01

352

Effect of air freezing, spray freezing, and pressure shift freezing on membrane integrity and viability of Lactobacillus rhamnosus GG  

Microsoft Academic Search

The objective of this work was to assess and compare the impact of three different freezing methods on the physiology of probiotic bacteria based on evaluation of vitality, membrane integrity and special metabolic properties. Lactobacillus rhamnosus GG (LGG) was used as a model strain and was analysed with the plate enumeration method and flowcytometric analyses (FCM) before and after treatment

Marcus Volkert; Edwin Ananta; Cornelius Luscher; Dietrich Knorr

2008-01-01

353

Study on the Realization of Zinc Point and the Zinc-Point Cell Comparison  

Microsoft Academic Search

Continuing our study on aluminum, tin, and silver points, a study on the realization of the zinc point was conducted. Zinc-point\\u000a cells were newly fabricated using 6N-nominal grade zinc samples, impurity elements of which were analyzed extensively based\\u000a on glow-discharge mass spectrometry (GDMS). The present paper reports the temperature measurements done using the newly fabricated\\u000a cells during the zinc freezing

J. V. Widiatmo; M. Sakai; K. Satou; K. Yamazawa; J. Tamba; M. Arai

2011-01-01

354

Freezing cleans food processing wastewater  

SciTech Connect

Snowfluent is a technology which atomizes wastewater effluent and sprays it into the air as ice crystals at cold temperatures. It has been found effective in treating municipal sewage and food processing wastes. This bulletin reviews pilot- and production-scale studies conducted at an Alberta malt producer to test whether the Snowfluent process has further applications for the treatment of food processing wastes. The study was designed to determine the percentage of nutrients removed by the technology, the point at which contaminants are reduced, the effect of the process on the shallow water table, and the health risk to operators involved.

Not Available

1998-01-01

355

The postpartum depression screening scale: is it valid to screen for antenatal depression?  

Microsoft Academic Search

The purpose of the study was to analyse for the first time the validity of a slightly modified version of the Portuguese Postpartum\\u000a Depression Screening Scale (PDSS), to be used as a screening instrument for antenatal depression. Specifically, the aims were\\u000a to analyse its psychometric properties, to determine PDSS cutoff points and associated conditional probabilities to screen\\u000a for depression according

Ana Telma Pereira; Sandra C. Bos; Mariana Marques; Berta R. Maia; Maria João Soares; José Valente; Ana Allen Gomes; António Macedo; Maria Helena Pinto de Azevedo

2011-01-01

356

Depression: What We Know.  

ERIC Educational Resources Information Center

|This booklet is concerned with the area of clinical depression. Questions about clinical depression are briefly answered in an overview section and are examined in greater detail in the five chapters that follow. In chapter 1, depression is defined and various types of depression are identified. The origins of depression are explored in the…

Lobel, Brana; Hirschfeld, Robert M. A.

357

Nutritional Interventions in Depression and Perinatal Depression  

PubMed Central

Depression is the leading cause of mental disability worldwide. Women who are depressed during pregnancy are at a higher risk for preterm delivery, preeclampsia, birth difficulties, and postpartum depression. The treatment of depression in conventional medicine has focused on physiological factors that lead to impaired neurotransmitter function and treatments to improve neurotransmitter function. Pharmaceutical substances pose risks for pregnant and lactating women, and lower risk options are preferred. Micronutrients, including certain B vitamins, folate, and docosahexaenoic acid (DHA), play a role in the synthesis and absorption of neurotransmitters. Experimental studies suggest that supplementation with specific micronutrients may alleviate depressive symptoms and improve birth outcomes in patients with perinatal depression. Alternative treatments for depression, including nutritional supplements, are an important treatment option for depressive symptoms while limiting potential side effects and treatment costs. This article explores the biological basis of perinatal depression and reviews the potential benefits of non-pharmacological interventions.

Rechenberg, Kaitlyn; Humphries, Debbie

2013-01-01

358

Thermosiphon solar water heater having freeze rupture protection  

SciTech Connect

A thermosiphon solar water heating system is described, having passive protection against freeze rupture during periods when insufficient solar energy exists for the system to generate heating and ambient air temperature conditions drop to the freezing point of water. It has a solar energy collector for generating heat, including cover for exposure to solar energy and ambient air. A water supply conduit is displaced from the cover, and a riser conduit is coupled to the water supply conduit and has an outlet. The riser conduit disposed between the cover and the water supply conduit so as to be in closer proximity to the cover than the water supply conduit. The riser conduit transfer heat to the water contained therein during periods when sufficient solar energy exists for the collector to generate heat, to cause water therein to become more buoyant than water in the supply conduit. The riser conduit cools the water contained therein more rapidly than the supply conduit cools the water contained in it during periods when insufficient solar energy exists for the collector to generate heat, and allowing the ambient temperature to cause water contained therein to be lowered in temperature to under 4/sup 0/C. and become more buoyant than water in the supply conduit the riser conduit discharges at its outlet water more buoyant than water in the supply conduit. A heated water storage tank is disposed adjacent and elevated above the solar collector. The outlet of the riser conduit is coupled to the water supply conduit.

Cole, S.W.

1986-07-15

359

Deliquesence and freezing of stratospheric aerosol observed by balloonborne backscattersondes  

SciTech Connect

Stratospheric sulfate aerosols, originating from the Mt. Pinatubo volcanic eruption, have been observed during three winters in the Arctic by balloonborne backscattersondes. A measured color index, defined as the quotient between the aerosol backscatter ratios at wavelengths 940 and 480 nm, provides information of the size of the observed particles. The effects of liquid particle growth, by water vapor uptake, clearly show up as changes in the color index, whereas measurements on other days indicate the particles to be frozen. Air parcel trajectories have been calculated, providing the temperature history of the observed particles. Evidences appear of a temperature hysteresis in the freezing and melting cycle of the aerosol, indicating melting temperatures around 215-220 K in good agreement with laboratory measurements, and freezing of the particles within less than 5 K above the ice frost point. The changes in color index of the liquid particles are in good agreement with predictions from theoretical model calculations of growth by water vapor uptake. 13 refs., 5 figs., 1 tab.

Larsen, N.; Knudsen, B. [Danish Meterological Institute, Copenhagen (Denmark); Rosen, J.M. [Univ. of Wyoming, Laramie, WY (United States)] [and others

1995-05-15

360

Fundamental Research on Freezing Process of Water Accompanied by Blockade  

NASA Astrophysics Data System (ADS)

Fundamental research was carried out on freezing process of water accompanied by blockade. Firstly, experiment on freezing using a vinyl vessel was performed. The vessel containing water was sealed and frozen in a low temperature bath. As internal presure increased, ice started to break suddenly and then continued to break frequently. Secondly, metal vessel was used and similar experiment was performed. Strain gauge was placed at eight points evenly distributed in circumferential direction on the vessel. It was found that the force acting on the vessel was so great that the vessel entered into a plastic region in very short time. It was also found that ice cracks influence the local strain value but the value is almost independent to its neighboring measurements. Approximate analysis was performed and compared with the experiment using metal vessel. The following two cases were assumed in the calculation. (1) Ice is so easy to break that the stress in the ice can be ignored. (2) Ice never break and always stay in elastic region. The experimental results laid somewhere between them but subsequently it approached the case (1).

Saito, Akio; Okawa, Seiji; Saito, Seiji

361

Freeze-Out Effects on n-Channel MOSFET's.  

National Technical Information Service (NTIS)

Surface admittance measurements have been carried out on (100) oriented 1-ohm cm n-channel silicon MOSFET's in the freeze-out regime. The freeze-out temperature accurately determines the amount of compensation. Measurements at different frequencies yield ...

S. Aymeloglu J. N. Zemel

1975-01-01

362

Freeze-fracture studies on Pneumocystis carinii  

Microsoft Academic Search

Ultrastructure of the trophozoite of Pneumocystis carinii was studied by the freeze-fracture technique. Nuclei and cytoplasmic organelles such as the endoplasmic reticulum, mitochondria, cytoplasmic vacuoles and small round bodies were observed. The mean number of nuclear pores was 8 per ?m2, which is small compared with that reported for other human pathogenic protozoa. In general, the density of nuclear pores

Hisao Yoshikawa; Hiroyuki Morioka; Yukio Yoshida

1987-01-01

363

Effects of freezing on isolated plant mitochondria  

Microsoft Academic Search

Mitochondria isolated from spinach leaves (Spinacia oleracea L.) and potato tubers (Solanum tuberosum L.) were partly injured when subjected to freezing for 2 to 4 h at-25°C in salt solutions in the absence of cryoprotectants. Damage was manifested by the inactivation of respiratory properties and increase in the permeability of the mitochondrial membranes. Decrease in respiratory control indicated that the

Regina Thebud; Kurt A. Santarius

1981-01-01

364

Hot water can freeze faster than cold?!?  

Microsoft Academic Search

We review the Mpemba effect, where intially hot water freezes faster than initially cold water. While the effect appears impossible at first sight, it has been seen in numerous experiments, was reported on by Aristotle, Francis Bacon, and Descartes, and has been well-known as folklore around the world. It has a rich and fascinating history, which culminates in the dramatic

Monwhea Jeng

2005-01-01

365

Freeze verification: time for a fresh approach  

Microsoft Academic Search

The administration's claim that some elements of a comprehensive nuclear freeze are unverifiable does not specify the nature of those elements and whether they represent a real threat to national security if we trusted the USSR to comply. The author contends that clandestine development of new weapons will have little strategic effect since both sides already have total destructive power.

Paine

1983-01-01

366

FREEZE-FRAME: Fast Action Stress Relief.  

ERIC Educational Resources Information Center

|Recent scientific research has proven that we can, not only manage our stress, we can even prevent it. Ways to achieve stress management are presented in this book. It details a method called FREEZE-FRAME, a process in which individuals mentally stop the chaos that surrounds them and then calmly contemplate their situation. The text opens with an…

Childre, Doc Lew

367

Scaling-Up Eutectic Freeze Crystallization  

Microsoft Academic Search

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) and water from a wide variety of aqueous process streams. Using EFC, processes producing large quantities of saline

F. E. Genceli

2008-01-01

368

Freeze-Drying Various Strains of Shigella.  

National Technical Information Service (NTIS)

Of six candidate strains of Shigella prepared in Brain Heart Infusion broth as freeze-dried vaccine, low survival rates were obtained with two of the most promising strains. Survival rates with these two strains were increased to acceptable levels when th...

S. Berman P. L. Altieri A. Groffinger J. P. Lowenthal S. B. Formal

1968-01-01

369

Melting, freezing, and coalescence of gold nanoclusters  

Microsoft Academic Search

We present a detailed molecular-dynamics study of the melting, freezing, and coalescence of gold nanoclusters within the framework of the embedded-atom method. Concerning melting, we find the process first to affect the surface (``premelting''), then to proceed inwards. The curve for the melting temperature vs cluster size is found to agree reasonably well with predictions of phenomenological models based on

Laurent J. Lewis; Pablo Jensen; Jean-Louis Barrat

1997-01-01

370

Method for freezing edible marine animals  

US Patent & Trademark Office Database

Various methods useful in connection with catching and freezing fish are disclosed. Also disclosed is an immersion freezer. In preferred embodiments, fish or other items to be frozen are immersed in a cooling medium. The cooling medium comprises an organic cooling agent, which preferably is a carbohydrate, sugar alcohol, glycoside, or non-toxic oil.

Knauf; Jeff (Sitka, AK)

2006-05-23

371

Unitarity Constraints on Asymmetric Freeze-In  

SciTech Connect

This paper considers unitarity and CPT constraints on asymmetric freeze-in, the use of freeze-in to store baryon number in a dark sector. In this scenario, Sakharov's out of equilibrium condition is satisfied by placing the visible and hidden sectors at different temperatures while a net visible baryon number is produced by storing negative baryon number in a dark sector. It is shown that unitarity and CPT lead to unexpected cancellations. In particular, the transfer of baryon number cancels completely at leading order. This note has shown that if two sectors are in thermal equilibrium with themselves, but not with each other, then the leading effect transferring conserved quantities between the two sectors is of order the the weak coupling connecting them to the third power. When freeze-in is used to produce a net baryon number density, the leading order effect comes from {Omicron}({lambda}{sup 3}) diagrams where the intermediate state that goes on-shell has a different visible baryon number than the final state visible baryon number. Models in which the correct baryon number is generated with freeze-in as the dominant source of abundance, typically require {lambda} {approx}> 10{sup -6} and m{sub bath} {approx}> TeV. m{sub bath} is the mass of the visible particle which communicates with the hidden sector. The lower window is potentially observable at the LHC.

Hook, Anson; /SLAC

2011-08-15

372

Food Freezing in the Intermediate Fluidized Bed.  

National Technical Information Service (NTIS)

A new food freezing method has been investigated using the so-called intermediate fluidized bed in which the food was fluidized together with small particles for aid of the fluidization and heat transfer of the food. Formed alumina and refined salt partic...

M. Yumiyama

1988-01-01

373

High tolerance to repeated cycles of freezing and thawing in different Trichinella nativa isolates.  

PubMed

Trichinella nativa is the most frequent Trichinella species in arctic wildlife and also the predominating species seen in Norwegian fauna. The adaptation of T. nativa to a cold climate is reflected by the well-documented freeze tolerance of its muscle larvae. The ability of the larvae to survive repeated freezing and thawing events has not however been elucidated and was investigated in the present study, using an Alaskan isolate and two isolates from coastal and inland Norway, respectively. Each T. nativa isolate was inoculated in foxes (Vulpes vulpes) and the muscle tissue obtained after 20 weeks was minced and divided into freezer bags. In the initial part of the study, the bags were exposed to either continuous freezing (-5 degrees C) for up to 7 weeks or freezing (-5 degrees C) for up to 7 weeks with seven overnight (+21 degrees C) thawing events. Once a week a bag was removed from each group, the meat was digested and muscle larvae isolated. In vitro assessment of larval viability was carried out based on larval motility (active vs non-active) and morphology, coiled (alive) or C-shaped (dead). Larval infectivity was subsequently bioassayed in mice, administering 500 larvae per mouse. The mice were euthanised 4 weeks post inoculation, the muscle digested and larvae per gram (lpg) and reproductive capacity index (RCI) were calculated. During the second part of the study, some of the minced fox muscle, exposed to the initial freeze protocol, was stored for a further 23 weeks at -18 degrees C prior to in vitro and in vivo assessment of larval viability and infectivity. The study demonstrated that Trichinella isolates originating from carnivores from higher northern latitudes expressed highest tolerance to freezing and that temperature fluctuations around freezing point, for up to 7 weeks, had little effect on larval infectivity. A negative effect of the initial repeated freeze-thaw events could be demonstrated once the larvae were exposed to longer periods of subsequent deep freezing. Furthermore, it was demonstrated that larval morphology and motility are not suitable for the assessment of infectivity of Trichinella larvae. It was concluded that bioassay in mice was the only suitable method currently available for assessing larval viability. PMID:18594862

Davidson, Rebecca K; Handeland, Kjell; Kapel, Christian M O

2008-07-02

374

Effect of freezing and thawing processes on soil aggregate stability  

Microsoft Academic Search

The effect of freezing and thawing on wet aggregate stability of soils formed on different parent materials was determined for different aggregate size groups (0.0–1.0; 1.0–2.0; and 2.0–4.0 mm), different water contents and for various freezing and thawing cycles (three, six and nine times) and freezing temperatures (?4 and ?18 °C). The initial wet aggregate stability decreased with freeze–thaw treatments

Taskin Oztas; Ferhan Fayetorbay

2003-01-01

375

Conditional and unconditional components of post-shock freezing  

Microsoft Academic Search

Rats received shocks in one apparatus, and post-shock “freezing” was then assessed in that apparatus or in a different one.\\u000a The assessment of freezing was made immediately after shock or after a 24-hour delay. Post-shock freezing was reduced when\\u000a the animals were tested in a different apparatus from that in which shocks had been administered. No reduction in freezing\\u000a was

Michael S. Fanselow

1980-01-01

376

Depression and Epilepsy  

MedlinePLUS

Depression You are here: Home About Epilepsy Related Conditions Depression Email Print Twitter Facebook MySpace Delicous Stumble ... susceptible to mood disorders. People with Epilepsy and Depression The results of studies to find out how ...

377

Vulnerability for Depression.  

National Technical Information Service (NTIS)

The vulnerability to depression and the antecedents for depression were collected and analyzed for an epidemiological pilot study of depression. Results of one test showed those categorized as 'invulnerables' as having a more positive opinion of their soc...

P. M. Lewinsohn

1980-01-01

378

Preclinical Models of Depression.  

National Technical Information Service (NTIS)

New animal models of human depression, especially endogenous depression, were developed. Depression was induced by means other than drugs. The model was validated by behavioral, neuroendocrine and neurochemical resemblances to the human disorder and by re...

B. J. Carroll

1983-01-01

379

Freezing rate determination by the isotopic composition of the ice  

Microsoft Academic Search

The distribution of an isotopic species, HDO (deuterium) or H218O (oxygen), in ice formed by the migration of a well-defined freezing front in water is dependent on the freezing rate. Development of a box diffusion model combined with the boundary layer concept leads to a possibility of prediction of the freezing rate in nature by the determination of the isotopic

Roland Souchez; Jean-Louis Tison; Jean Jouzel

1987-01-01

380

Simulation of Heat Transfer in Freezing Soils Using ABAQUS  

Microsoft Academic Search

Freezing saturated soils are mixtures of solid particles, water, and ice. Heat transfer in freezing soils is a complex process because of the multi-phase nature of the mixture. The phase change of the liquid part adds complexity, since not all water changes phase at the freezing temperature. Difficulties with convergence are known to appear when simulating the process. A numerical

Ming Zhu; Radoslaw L. Michalowski

381

Molecular dynamics simulations of freezing of water and salt solutions  

Microsoft Academic Search

Results of extensive molecular dynamics simulations of freezing of neat water and aqueous sodium chloride solutions are reported. The process of water freezing in contact with an ice patch is analyzed at a molecular level and a robust simulation protocol within the employed force field is established. Upon addition of a small amount of NaCl brine rejection from the freezing

Luboš Vrbka; Pavel Jungwirth

2007-01-01

382

Nucleation of Freezing in Supercooled Water by Cavitation  

Microsoft Academic Search

NUCLEATION of freezing in supercooled liquids by cavitation has been ascribed to a momentary large increase in the degree of supercooling, induced by the high transient pressures generated by a collapsing cavity. This is a plausible mechanism for substances which contract on freezing; for substances such as water, which expand on freezing, it seems less satisfactory1. Hickling2, however, has proposed

M. N. Plooster

1968-01-01

383

Recent Progress in the Freeze-Etching Technique  

Microsoft Academic Search

The freeze-etching technique must be improved if structures at the molecular size level are to be seen. The limitations of the technique are discussed here together with the progress made in alleviating them. The vitrification of living specimens is limited by the fact that very high freezing rates are needed. The critical freezing rate can be lowered on the one

H. Moor

1971-01-01

384

Sources of Data on Freezing Rain and Resulting Damages  

Microsoft Academic Search

Freezing rain produces major damages each year in the United States, and various affected groups continue to seek data on the incidence and losses produced by freezing rain. The various kinds of data available about freezing rain and related damages have been identified and assessed as part of a project to develop long-term databases. Data include long-term records of the

Tamara G. Creech

2003-01-01

385

Alcoholism & depression.  

PubMed

One out of 2 Americans report drinking on a routine basis, making the excessive consumption of alcohol the third leading cause of preventable death in America (). Alcoholism and depression are common comorbidities that home healthcare professionals frequently encounter. To achieve the best patient outcomes, alcoholism should be addressed initially. Although all age groups are at risk, alcoholism and depression occur in more than 8 percent of older adults. Prevention through identifying alcohol use early in adolescence is vital to reduce the likelihood of alcohol dependence. This article provides an overview of the long-term effects of alcohol abuse, including alcoholic cirrhosis and hepatic encephalopathy. The diagnostic criteria for substance dependence and ideas for nonthreatening screening questions to use with patients who are adolescent or older are discussed. While providing patient care, home healthcare nurses share the patient's intimate home environment. This environment is perceived as a safe haven by the patient and home care nurses can take advantage of counseling and treatment opportunities in this nonthreatening environment. PMID:23026991

Hall, Mellisa

2012-10-01

386

Seasonal freeze resistance of rainbow smelt (Osmerus mordax) is generated by differential expression of glycerol-3-phosphate dehydrogenase, phosphoenolpyruvate carboxykinase, and antifreeze protein genes.  

PubMed

In winter, rainbow smelt (Osmerus mordax) accumulate glycerol and produce an antifreeze protein (AFP), which both contribute to freeze resistance. The role of differential gene expression in the seasonal pattern of these adaptations was investigated. First, cDNAs encoding smelt and Atlantic salmon (Salmo salar) phosphoenolpyruvate carboxykinase (PEPCK) and smelt glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were cloned so that all sequences required for expression analysis would be available. Using quantitative PCR, expression of beta actin in rainbow smelt liver was compared with that of GAPDH in order to determine its validity as a reference gene. Then, levels of glycerol-3-phosphate dehydrogenase (GPDH), PEPCK, and AFP relative to beta actin were measured in smelt liver over a fall-winter-spring interval. Levels of GPDH mRNA increased in the fall just before plasma glycerol accumulation, implying a driving role in glycerol synthesis. GPDH mRNA levels then declined during winter, well in advance of serum glycerol, suggesting the possibility of GPDH enzyme or glycerol conservation in smelt during the winter months. PEPCK mRNA levels rose in parallel with serum glycerol in the fall, consistent with an increasing requirement for amino acids as metabolic precursors, remained elevated for much of the winter, and then declined in advance of the decline in plasma glycerol. AFP mRNA was elevated at the onset of fall sampling in October and remained elevated until April, implying separate regulation from GPDH and PEPCK. Thus, winter freezing point depression in smelt appears to result from a seasonal cycle of GPDH gene expression, with an ensuing increase in the expression of PEPCK, and a similar but independent cycle of AFP gene expression. PMID:16555199

Liebscher, Ryan S; Richards, Robert C; Lewis, Johanne M; Short, Connie E; Muise, Denise M; Driedzic, William R; Ewart, K Vanya

2006-02-01

387

Depression in adolescence.  

PubMed

Major depression is a common mental health disorder in adolescents that predicts a significant risk for recurrence in adulthood. Suicide is the third most frequent cause of deaths in this age group, and depression is a significant risk factor for suicidal ideation and attempts. Risks for depression and suicidal ideation are reviewed, and subtypes of depression are discussed. Difficulties associated with identification of depression and suicidal ideation in adolescents and biologic therapies for adolescent depression are reviewed. PMID:11753112

Sampson, S M; Mrazek, D A

2001-12-01

388

Freezing survival, body ice content and blood composition of the freeze-tolerant European common lizard, Lacerta vivipara  

Microsoft Academic Search

To investigate the freeze tolerance of the European common lizard, Lacerta vivipara, we froze 17 individuals to body temperatures as low as -4 °C under controlled laboratory conditions. The data show that this species tolerates the freezing of 50% of total body water and can survive freezing exposures of at least 24-h duration. Currently, this represents the best known development

Y. Voituron; J. Storey; C. Grenot; K. Storey

2002-01-01

389

Freezing curve-based monitoring to quickly evaluate the viability of biological materials subject to freezing or thermal injury  

Microsoft Academic Search

This paper is aimed at investigating the roles of freezing dynamics of a liquid droplet to characterize the properties of the material. In particular, freezing curve-based monitoring was proposed to quickly evaluate the viability of biological materials subject to freezing, re-warming, or other kinds of injury, which is an extremely important issue in practices such as cryobiology, hyperthermia, or freshness

Jing Liu; Yi-Xin Zhou

2003-01-01

390

Effects of Freeze\\/Thaw Index, Air Temperature, and Snow Cover on Seasonal Freeze and Thaw Depths in Russia  

Microsoft Academic Search

Seasonal freezing and thawing processes in cold regions play an exceedingly important role in ecosystem diversity, productivity, and the Arctic hydrological system in general. Long-term changes in seasonal freeze and thaw depths are also important indicators of climate change. Only sparse observational measurements of seasonal freeze and thaw depths are available in permafrost and seasonally frozen ground regions. However, soil

O. W. Frauenfeld; T. Zhang; R. G. Barry; D. Gilichinsky; A. J. Etringer

2003-01-01

391

Intercomparison of Copper Fixed-Point Cells by Using Pt/Pd Thermocouples  

NASA Astrophysics Data System (ADS)

The objective of the EUROMET Project No. 844 in the field of thermometry was the intercomparison of the freezing temperatures of the copper fixed-point cells ( t 90 = 1084.62°C) of the participating laboratories by using Pt/Pd thermocouples. For most of the 13 participating laboratories, agreement of the freezing temperatures of the different copper fixed points within ±0.06 K was found. Furthermore, the results of the intercomparison show that Pt/Pd thermocouples are suitable for use as transfer standards for the dissemination of temperatures and to approximate the ITS-90, at least up to the freezing point of copper.

Edler, F.; Anagnostou, M.; Bojkovski, J.; Gaita, S.; García, C.; Grudniewicz, E.; Helgesen, F.; Ivarsson, J.; Pauza, A.; Rosenkranz, P.; Smid, M.; Weckström, T.; Zvizdic, D.

2008-02-01

392

Interpersonal processes in depression.  

PubMed

Humans have an intrinsic need for social connection; thus, it is crucial to understand depression in an interpersonal context. Interpersonal theories of depression posit that depressed individuals tend to interact with others in a way that elicits rejection, which increases their risk for future depression. In this review, we summarize the interpersonal characteristics, risk factors, and consequences of depression in the context of the relevant theories that address the role of interpersonal processes in the onset, maintenance, and chronicity of depression. Topics reviewed include social skills, behavioral features, communication behaviors, interpersonal feedback seeking, and interpersonal styles as they relate to depression. Treatment implications are discussed in light of the current research on interpersonal processes in depression, and the following future directions are discussed: developing integrative models of depression, improving measurement of interpersonal constructs, examining the association between interpersonal processes in depression and suicide, and tailoring interventions to target interpersonal processes in depression. PMID:23297787

Hames, Jennifer L; Hagan, Christopher R; Joiner, Thomas E

2013-01-03

393

Understanding the freezing of biopharmaceuticals: first-principle modeling of the process and evaluation of its effect on product quality.  

PubMed

Freezing and thawing are important process steps in the manufacture of numerous biopharmaceuticals. It is well established that these process steps can significantly influence product quality attributes (PQA). Herein, we describe a physico-mathematical model to predict product temperature profiles based on the freezing program as input parameter in a commercial freeze-thaw module. Applying this model, the time from first nucleation until the last point to freeze (LPF) reaching -5°C and the time from -5°C at LPF to -30°C at LPF was varied to study the effect on PQA in a full factorial design. Effects of process parameter settings on a typical fully formulated, highly concentrated monoclonal antibody (mAb) solution as well as highly concentrated mAb solution formulated with buffer only were investigated. We found that both process phases affected PQA, such as aggregates by size-exclusion chromatography, polydispersity index by dynamic light scattering, and number of subvisible particles and turbidity in a complex way. In general, intermediate cooling and freezing times resulted in overall optimized PQA. Fully formulated mAb solution containing cryoprotectant and nonionic surfactant was significantly less affected by freezing-thawing than mAb solution formulated in buffer only. PMID:23775776

Radmanovic, Nikola; Serno, Tim; Joerg, Susanne; Germershaus, Oliver

2013-06-17

394

Assessment of depression in medical patients: A systematic review of the utility of the Beck Depression Inventory-II  

PubMed Central

To perform a systematic review of the utility of the Beck Depression Inventory for detecting depression in medical settings, this article focuses on the revised version of the scale (Beck Depression Inventory-II), which was reformulated according to the DSM-IV criteria for major depression. We examined relevant investigations with the Beck Depression Inventory-II for measuring depression in medical settings to provide guidelines for practicing clinicians. Considering the inclusion and exclusion criteria seventy articles were retained. Validation studies of the Beck Depression Inventory-II, in both primary care and hospital settings, were found for clinics of cardiology, neurology, obstetrics, brain injury, nephrology, chronic pain, chronic fatigue, oncology, and infectious disease. The Beck Depression Inventory-II showed high reliability and good correlation with measures of depression and anxiety. Its threshold for detecting depression varied according to the type of patients, suggesting the need for adjusted cut-off points. The somatic and cognitive-affective dimension described the latent structure of the instrument. The Beck Depression Inventory-II can be easily adapted in most clinical conditions for detecting major depression and recommending an appropriate intervention. Although this scale represents a sound path for detecting depression in patients with medical conditions, the clinician should seek evidence for how to interpret the score before using the Beck Depression Inventory-II to make clinical decisions.

Wang, Yuan-Pang; Gorenstein, Clarice

2013-01-01

395

Chiral condensate and chemical freeze-out  

NASA Astrophysics Data System (ADS)

We consider a chemical freeze-out mechanism which is based on a strong medium dependence of the rates for inelastic flavor-equilibrating collisions based on the delocalization of hadronic wave functions and growing hadronic radii when approaching the chiral restoration. We investigate the role of mesonic (pion) and baryonic (nucleon) fluctuations for melting the chiral condensate in the phase diagram in the ( T, ?)-plane. We apply the PNJL model beyond mean-field and present an effective generalization of the chiral perturbation theory result which accounts for the medium dependence of the pion decay constant while preserving the GMOR relation. We demonstrate within a schematic resonance gas model consisting of a variable number of pionic and nucleonic degrees of freedom that within the above model a quantitative explanation of the hadonic freeze-out curve and its phenomenological conditions can be given.

Blaschke, D. B.; Berdermann, J.; Cleymans, J.; Redlich, K.

2011-12-01

396

Ground freezing for containment of hazardous waste  

SciTech Connect

The freezing of ground for the containment of subsurface hazardous waste is a promising method that is environmentally friendly and offers a safe alternative to other methods of waste retention in many cases. The frozen soil method offers two concepts for retaining waste. One concept is to freeze the entire waste area into a solid block of frozen soil thus locking the waste in situ. For small areas where the contaminated soil does not include vessels that would rupture from frost action, this concept may be simpler to install. A second concept, of course, is to create a frozen soil barrier to confine the waste within prescribed unfrozen soil boundaries; initial research in this area was funded by EPA, Cincinnati, OH, and the Army Corps of Engineers. The paper discusses advantages and limitations, a case study from Oak Ridge, TN, and a mesh generation program that simulates the cryogenic technology.

Sayles, F.N.; Iskandar, I.K.

1998-07-01

397

Study of Transient Nuclei near Freezing  

NASA Astrophysics Data System (ADS)

The molasses tail in dense hard core fluids is investigated by extensive event-driven molecular dynamics simulation through the orientational autocorrelation functions. Near the fluid- solid phase transition, there exist three regimes in the relaxation of the pair orientational autocorrelation function, namely the kinetic, molasses (stretched exponential), and diffusional power decay. The density dependence of both the molasses and diffusional power regimes are evaluated and the latter compares with theoretical predictions in three dimensions. The largest cluster at the freezing density of only a few sphere diameter in size persist for only about 30 picoseconds (˜2.8 x10-11[s]). The most striking observation through the bond orientatinal order parameter is the dramatic increase of the cluster size as the freezing density is approached.

Isobe, Masaharu; Alder, Berni

2011-03-01

398

Study of Transient Nuclei near Freezing  

NASA Astrophysics Data System (ADS)

The molasses tail in dense hard core fluids is investigated by extensive event-driven molecular dynamics simulation through the orientational autocorrelation functions. Near the fluid-solid phase transition, there exist three regimes in the relaxation of the pair orientational autocorrelation function, namely the kinetic, molasses (stretched exponential), and diffusional power decay. The density dependence of both the molasses and diffusional power regimes are evaluated and the latter compares with theoretical predictions in three dimensions. The largest cluster at the freezing density of only a few sphere diameter in size persist for only about 30 picoseconds (˜ 2.8 × 10(-11) [s]). The most striking observation through the bond orientatinal order parameter is the dramatic increase of the cluster size as the freezing density is approached.

Isobe, M.; Alder, B. J.

399

Freeze-Out Parameters: Lattice Meets Experiment  

NASA Astrophysics Data System (ADS)

We present our results for ratios of higher order fluctuations of electric charge as functions of the temperature. These results are obtained in a system of 2+1 quark flavors at physical quark masses and continuum extrapolated. We compare them to preliminary data on higher order moments of the net electric charge distribution from the STAR collaboration. This allows us to determine the freeze-out temperature and chemical potential from first principles. We also show continuum-extrapolated results for ratios of higher order fluctuations of baryon number. These will allow us to test the consistency of the approach, by comparing them to the corresponding experimental data (once they become available) and thus, extracting the freeze-out parameters in an independent way.

Borsányi, S.; Fodor, Z.; Katz, S. D.; Krieg, S.; Ratti, C.; Szabó, K. K.

2013-08-01

400

Freezing of colloidal suspensions in confined spaces  

SciTech Connect

Simulation and experimental techniques have been developed to study the phase properties of a fluid confined between two closely-spaced walls and applied to investigate systems of charge-stabilized colloidal suspensions between repulsive smooth walls in contact with a reservoir. The phase behavior of confined suspensions is studied as a function of bulk particle volume fraction, surface charge, and wall separation. Complete crystallization within a fixed-size gap at sufficiently small wall separation occurs at bulk volume fractions well below the bulk freezing volume fraction. The simulations show a strong dependence of the freezing transition on a preferred wall separation corresponding to an integral number of layers. The simulation predictions match experimental observations at wall separations from five to ten particle diameters. 42 refs., 10 figs., 1 tab.

Hug, J.E.; Swol, F. van; Zukoski, C.F. (Univ. of Illinois, Urbana, IL (United States))

1995-01-01

401

Drying a tuberculosis vaccine without freezing  

Microsoft Academic Search

With the increasing incidence of tuberculosis and drug resistant disease in developing countries due to HIV\\/AIDS, there is a need for vaccines that are more effective than the present bacillus Calmette-Guérin (BCG) vaccine. We demonstrate that BCG vaccine can be dried without traditional freezing and maintained with remarkable refrigerated and room-temperature stability for months through spray drying. Studies with a

Y.-L. Wong; Samantha Sampson; W. A. Germishuizen; Sunali Goonesekera; Giovanni Caponetti; Jerry Sadoff; B. R. Bloom; David Edwards

2007-01-01

402

Hadron Freeze-out and QGP Hadronization  

Microsoft Academic Search

Abundances and $m_\\\\bot$-spectra of strange and other hadronic particles emanating from central 158-200 A GeV reactions between nuclei are found to originate from a thermally equilibrated, deconfined source in chemical non-equilibrium. Physical freeze-out parameters and physical conditions (pressure, specific energy, entropy, and strangeness) are evaluated. Five properties of the source we obtain are as expected for direct hadron emission (hadronization)

Johann Rafelski; Jean Letessier

1999-01-01

403

Phase diagram for freeze-dried persimmon  

Microsoft Academic Search

Phase transitions of freeze-dried persimmon in a large range of moisture content were determined by differential scanning calorimetry (DSC). In order to study this transitions at low and intermediate moisture content domains, samples were conditioned by adsorption at various water activities (aw=0.11–0.90) at 25°C. For the high moisture content region, samples were obtained by water addition. At aw?0.75 two glass

P. J. A. Sobral; V. R. N. Telis; A. M. Q. B. Habitante; A. Sereno

2001-01-01

404

Hydrocarbon exclusion from ground water during freezing  

Microsoft Academic Search

Bench-scale studies were conducted using a constant-head ground-water flow chamber and natural soil. Initial experiments with chlorides and dye were conducted to test the hydraulic and adsorptive characteristics of the chamber. A constant flow of phenol was then introduced into the chamber and contaminant movement with time was monitored under freezing and nonfreezing conditions. The chamber was located in a

Mark A. Tumeo; Bret Davidson

1993-01-01

405

Vogel-Fulcher freezing in relaxor ferroelectrics  

SciTech Connect

A physical mechanism for the freezing of polar nanoregions (PNRs) in relaxor ferroelectrics is presented. Assuming that the activation energy for the reorientation of a cluster of PNRs scales with the mean volume of the cluster, the characteristic relaxation time {tau} is found to diverge as the cluster volume reaches the percolation limit. Applying the mean field theory of continuum percolation, the familiar Vogel-Fulcher equation for the temperature dependence of {tau} is derived.

Pirc, R.; Blinc, R. [Jozef Stefan Institute, P.O. Box 3000, 1001 Ljubljana (Slovenia)

2007-07-01

406

Solar desalination by freezing and distillation  

Microsoft Academic Search

It is noted that among seawater desalination processes the absorption-freeze vapor compression processes based on the thermal heat pump, although untested commercially and still in the development stage, appears technically and economically an attractive application of low-grade (exergy) solar heat. The distillation processes proposed here may be conveniently powered by low-grade solar heat (from flat plate solar collectors). It is

G. Kvajic

1981-01-01

407

Fluctuations in US Freezing Rain Days  

Microsoft Academic Search

Freezing rain occurrences during a 50-year period, 1949\\/1950–1998\\/1999, derived from carefully examined records of 161 first-order stations distributed across the United States, were assessed for temporal fluctuations and trends. Classification of station fluctuations based on five 10-year periods revealed five unique distribution types in areas east of the Rockies. One of these five distributions, for stations located in the western

David Changnon; Russell Bigley

2005-01-01

408

Steam consumption reduction by eutectic freeze crystallization  

SciTech Connect

Steam production in American beet sugar factories can be reduced by 600 pounds per ton of beets by using hydrate freeze crystallization in place of pan evaporators for sugar crystallization. This is a relatively constant number, regardless of current factory energy use. Further reduction is limited by the juice heating needs in the purification operations. Steam for juice heating is 20 to 30% on beets, or 400 to 600 pounds of steam per ton. In efficient factories this is about the steam flow to the evaporators when the pan crystallizers are replaced by freeze crystallization. An approach is described here for a rapid evaluation of effects on the steam balance of basic process changes. It provides a visual guide to restructuring the steam balance that simplifies optimization when such changes are made. The graphic approach is useful in illustrating methods of reducing energy use in a sugar factory, in addition to the current analysis of integration of the hydrate freeze process. For example, membrane and vapor recompression evaporators for juice concentration must be accompanied by major factory modifications to produce any net savings of steam. The reason is the needs for specific steam quantity and quality for the pan evaporators and juice heaters, supplied through the current evaporator trains. Reduction of the steam rate below 25 to 35% on beets will require changes to the conventional juice purification process.

Bichsel, S.E.; Cleary, M.; Barron, T.S.; Heist, J.A.

1985-01-01

409

Disaggregating meteorites by automated freeze thaw  

NASA Astrophysics Data System (ADS)

An automated freeze-thaw (AFT) instrument for disaggregating meteorites is described. Meteorite samples are immersed in 18.2 M? water and hermetically sealed in a clean 30 ml Teflon vial. This vial and its contents are dipped between baths of liquid nitrogen and hot water over a number of cycles by a dual-stepper motor system controlled by LabView. Uniform and periodic intervals of freezing and thawing induce multiple expansions and contractions, such that cracks propagate along natural flaws in the meteorite for a sufficient number of AFT cycles. For the CR2 chondrite NWA801, the boundaries between different phases (i.e., silicates, metal, matrix) became progressively weaker and allowed for an efficient recovery of 500 individual chondrules and chondrule fragments spanning 0.2-4.7 mm diameters after 243 AFT cycles over 103.3 h. Further FT experiments on a basalt analog showed that the time required for freezing and thawing the same number of cycles can be reduced by a factor of ~4.

Charles, Christopher R. J.

2011-06-01

410

Atmospheric freeze drying assisted by power ultrasound  

NASA Astrophysics Data System (ADS)

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.

Santacatalina, J. V.; Cárcel, J. A.; Simal, S.; Garcia-Perez, J. V.; Mulet, A.

2012-12-01

411

Intracellular freezing, viability, and composition of fat body cells from freeze-intolerant larvae of Sarcophaga crassipalpis.  

PubMed

Although it is often assumed that survival of freezing requires that ice formation must be restricted to extracellular compartments, fat body cells from freeze-tolerant larvae of the gall fly, Eurosta solidaginis (Diptera, Tephritidae) survive intracellular freezing. Furthermore, these cells are highly susceptible to inoculative freezing by external ice, undergo extensive lipid coalescence upon thawing, and survive freezing better when glycerol is added to the suspension medium. To determine whether these traits are required for intracellular freeze tolerance or whether they are incidental and possessed by fat body cells in general, we investigated the capacity of fat body cells from nondiapause-destined and diapause-destined (i.e., cold-hardy) larvae of the freeze-intolerant flesh fly Sarcophaga crassipalpis (Diptera, Sarcophagidae) to survive intracellular freezing. Fat body cells from both types of larvae were highly susceptible to inoculative freezing; all cells froze between -3.7 to -6.2 degrees C. The highest rates for survival of intracellular freezing occurred at -5 degrees C. The addition of glycerol to the media markedly increased survival rates. Upon thawing, the fat body cells showed little or no lipid coalescence. Fat body cells from E. solidaginis had a water content of only 35% compared to cells from S. crassipalpis larvae that had 52-55%; cells with less water may be less likely to be damaged by mechanical forces during intracellular freezing. PMID:11746564

Davis, D J; Lee, R E

2001-12-01

412

Distraction and depressive cognitions  

Microsoft Academic Search

Recent advances in the treatment of depression have focused on the cognition of patients, not as a symptom of depression but as a probable cause. Research supporting such developments focuses on descriptions of the content of depressed cognitions. The present study using standard cognitive techniques examined depressive cognitions as processes trying to determine the effects of the operation of these

Lester Krames; M. R. MacDonald

1985-01-01

413

The Great Depression  

NSDL National Science Digital Library

Students will understand the personal impact of the depression on the lives of Americans. We will follow Utah\\'s Social Studies core curriculum Standard 6: Students will understand how the Great Depression and the New Deal affected the United States. Objective 1 Investigate the impact of the Great Depression on the United States. * Analyze the major causes of the Great Depression. ...

Randyandamber

2007-11-30

414

Childhood and Adolescent Depression  

Microsoft Academic Search

Major depression affects 3 to 5 percent of children and adolescents. Depression negatively impacts growth and devel- opment, school performance, and peer or family relationships and may lead to suicide. Biomedical and psychosocial risk factors include a family history of depression, female sex, childhood abuse or neglect, stressful life events, and chronic illness. Diagnostic criteria for depression in children and

SHASHI K. BHATIA; SUBHASH C. BHATIA

2007-01-01

415

Embodiment, mindfulness, and depression  

Microsoft Academic Search

In this paper we will present results of a series of studies investigating the embodiment of depression. The first series of studies analyzed gait patterns in depression. Using a motion capture system we investigated (1) whether dynamic gait patterns of currently and formerly depressed patients differ from never depressed people and (2) whether mindfulness-based cognitive therapy (MBCT) normalize gait patterns

J. Michalak; J. Burg; T. Heidenreich; N. F. Troje

2011-01-01

416

Depression in cognitive impairment.  

PubMed

Depression and cognitive disorders, including dementia and mild cognitive impairment, are common in the elderly. Depression is also a common feature of cognitive impairment although the symptoms of depression in cognitive impairment differ from depression without cognitive impairment. Pre-morbid depression approximately doubles the risk of subsequent dementia. There are two predominant, though not mutually exclusive, constructs linking pre-morbid depression to subsequent cognitive impairment: Alzheimer's pathology and the vascular depression hypothesis. When evaluating a patient with depression and cognitive impairment, it is important to obtain caregiver input and to evaluate for alternative etiologies for depressive symptoms such as delirium. We recommend a sequential approach to the treatment of depression in dementia patients: (1) a period of watchful waiting for milder symptoms, (2) psychosocial treatment program, (3) a medication trial for more severe symptoms or failure of psychosocial interventions, and (4) possible ECT for refractory symptoms. PMID:23933974

Pellegrino, Laurel D; Peters, Matthew E; Lyketsos, Constantine G; Marano, Christopher M

2013-09-01

417

Natural freezing survival by painted turtles Chrysemys picta marginata and C. picta bellii.  

PubMed

Hatchlings of both the Midland (Chrysemys picta marginata) and Western (C. picta bellii) subspecies of the painted turtle tolerate the freezing of extracellular body fluids while overwintering in terrestrial nests. Fall-collected hatchlings survived 3 days of continuous freezing at -2.5 degrees C, with ice contents of 43.5 +/- 1.0% of total body water (SE; n = 24) for C. picta marginata and 46.5 +/- 0.8% (n = 32) for C. picta bellii. Survival times dropped to 4-5 h when temperature was lowered to -4 degrees C, correlated with ice contents of greater than or equal to 50%. However, C. picta marginata tested immediately after excavation from nests in the spring showed greater freeze tolerance, with survival extending to 11 days at -2.5 degrees C and a higher mean ice content of 50.2 +/- 1.2% (n = 6). Spring hatchlings also had high supercooling points, -1.07 +/- 0.13 degrees C (n = 8), that dropped within 3 days to -4.83 +/- 0.83 degrees C (n = 4), suggesting a breakdown of endogenous ice-nucleating agents when hibernation ended. A search for possible cryoprotectants showed that both subspecies accumulated glucose and lactate in liver during freezing (net increase = 3-13 mumols/g wet wt); both also maintained large free amino acid pools in organs, with taurine making up 21-47% of the total. PMID:1558223

Churchill, T A; Storey, K B

1992-03-01

418

Molecular modeling of freezing of simple fluids confined within carbon nanotubes  

NASA Astrophysics Data System (ADS)

We report Monte Carlo simulation results for freezing of Lennard-Jones carbon tetrachloride confined within model multiwalled carbon nanotubes of different diameters. The structure and thermodynamic stability of the confined phases, as well as the transition temperatures, were determined from parallel tempering grand canonical Monte Carlo simulations and free-energy calculations. The simulations show that the adsorbate forms concentric molecular layers that solidify into defective quasi-two-dimensional hexagonal crystals. Freezing in such concentric layers occurs via intermediate phases that show remnants of hexatic behavior, similar to the freezing mechanism observed for slit pores in previous works. The adsorbate molecules in the inner regions of the pore also exhibit changes in their properties upon reduction of temperature. The structural changes in the different regions of adsorbate occur at temperatures above or below the bulk freezing point, depending on pore diameter and distance of the adsorbate molecules from the pore wall. The simulations show evidence of a rich phase behavior in confinement; a number of phases, some of them inhomogeneous, were observed for the pore sizes considered. The multiple transition temperatures obtained from the simulations were found to be in good agreement with recent dielectric relaxation spectroscopy experiments for CCl4 confined within multiwalled carbon nanotubes.

Hung, Francisco R.; Coasne, Benoit; Santiso, Erik E.; Gubbins, Keith E.; Siperstein, Flor R.; Sliwinska-Bartkowiak, Malgorzata

2005-04-01

419

Melting\\/freezing behavior of a fluid confined in porous glasses and MCM-41: Dielectric spectroscopy and molecular simulation  

Microsoft Academic Search

We report both experimental measurements and molecular simulations of the melting and freezing behavior of fluids in nanoporous media. The experimental studies are for nitrobenzene in the silica-based pores of controlled pore glass, Vycor, and MCM-41. Dielectric relaxation spectroscopy is used to determine melting points and the orientational relaxation times of the nitrobenzene molecules in the bulk and the confined

Malgorzata Sliwinska-Bartkowiak; Grazyna Dudziak; Roman Sikorski; Roman Gras; Ravi Radhakrishnan; Keith E. Gubbins

2001-01-01

420

Can stress cause depression?  

PubMed

The central issue raised in this paper is: can stress cause depression? Phrased more precisely: can stress cause brain disturbances thought to underlie (certain forms of) depression or particular components of the depressive syndrome. Focussing on 5-HT and the stress hormones, this question was answered in the affirmative, based on the following two considerations: (1) changes in the 5-HT and stress hormone systems produced by sustained stress, mimic to a substantial extent the disturbances in these systems that may be observed in depression; (2) substantial evidence indicates that the 5-HT and stress hormone disturbances in depression are of pathophysiological significance and not merely a consequence of the depressed state or a product of stress generated by the depressed state. Furthermore, the question was raised whether a depression type could be identified particularly stress-inducible. This question, too, was answered in the affirmative. The depression type in question was named anxiety/aggression-driven depression and characterized on three levels: psychopathologically, biologically and psychologically. Preferential treatment of this depression type was discussed. In studying stress-inducible depression biological depression research should shift focus from depression per se to the neurobiological sequelae of stress. Treatment of stress-inducible depressions and particularly its prevention should be geared towards reduction of stress and stress sensitiveness, utilising both biological and psychological means. PMID:16166019

van Praag, Herman M

2005-01-01

421

Can stress cause depression?  

PubMed

The central issue raised in this paper is: can stress cause depression? Phrased more precisely: can stress cause brain disturbances thought to underlie (certain forms of) depression or particular components of the depressive syndrome. Focussing on 5-hydroxytryptamine (5-HT) and the stress hormones, this question was answered in the affirmative, based on the following two considerations: changes in the 5-HT and stress hormone systems produced by sustained stress mimic to a substantial extent the disturbances in these systems that may be observed in depression. Substantial evidence indicates that the 5-HT and stress hormone disturbances in depression are of pathophysiological significance and not merely a consequence of the depressed state or a product of stress generated by the depressed state. Furthermore, the question was raised whether a depression type could be identified particularly stress-inducible. This question, too, was answered in the affirmative. The depression type in question was named anxiety/aggression-driven depression and characterized on three levels: psychopathologically, biologically and psychologically. Preferential treatment of this depression type was discussed. In studying stress-inducible depression, biological depression research should shift focus from depression per se to the neurobiological sequelae of stress. Treatment of stress-inducible depressions and particularly its prevention should be geared towards reduction of stress and stress sensitiveness, utilising both biological and psychological means. PMID:15363612

van Praag, H M

2004-08-01

422

Personality disorders in bipolar and depressive disorders  

Microsoft Academic Search

The association of mood disorders with personality disorders (PDs) is relevant from a clinical, therapeutic and prognostic point of view. To examine this issue, we compared the prevalence of DSM-III-R personality disorders assessed with SCID-II in patients with depressive (n=117) and bipolar (n=71) disorders both recovered from a major depressive index episode that needed hospital admission. PDs prevalence and comorbidity

Alessandro Rossi; Maria Grazia Marinangeli; Giancarlo Butti; Antonella Scinto; Loredana Di Cicco; Artemis Kalyvoka; Concetta Petruzzi

2001-01-01

423

Fibromyalgic Syndrome: Depression and Abnormal Illness Behavior  

Microsoft Academic Search

This study reports psychological symptoms assessed in 327 patients with fibromyalgia (FS) in a multicenter investigation. Two self-report scales, in their validated Italian translations, were used for screening: the CES-D (the Center of Epidemiologic Studies-Depression) developed at the NIMH for measuring depression and the Illness Behavior Questionnaire (IBQ) developed by Pilowsky and Spence. The cutoff point of 23 in the

M. Ercolani; G. Trombini; R. Chattat; C. Cervini; G. Piergiacomi; F. Salaffi; S. Zeni; R. Marcolongo

1994-01-01

424

Ethnocultural Differences in Prevalence of Adolescent Depression  

Microsoft Academic Search

Data from an ethnically diverse sample of middle school (Grades 6–8) students (n = 5,423) are analyzed for ethnic differences in major depression. The point prevalence of major depression was 8.4% without and 4.3% with impairment. Data were sufficient to calculate prevalences for nine ethnic groups. Prevalences adjusted for impairment ranged from 1.9% for youths of Chinese descent to 6.6%

Robert E. Roberts; Catherine R. Roberts; Y. Richard Chen

1997-01-01

425

Point Groups  

NSDL National Science Digital Library

This exercise involves identifying symmetry in crystals and using that information to assign crystals to crystal systems and point groups. Students examine cardboard models and wooden blocks and fill their symmetry elements into a table. Then they figure out what what crystal system and point group each sample belongs to and fill in another table.

Perkins, Dexter

426

Freezing and ice crystals formed in a cylindrical food model: part II. Comparison between freezing at atmospheric pressure and pressure-shift freezing  

Microsoft Academic Search

Cylindrical gelatin gels were pressure-shift frozen at different pressure levels (100, 150 and 200 MPa). Temperature and pressure profiles were compared and the maximum supercooling obtained after pressure release was evaluated. A comparison between the freezing steps at atmospheric pressure and those of pressure-shift freezing was carried out to compare the time steps during the processes. The degree of supercooling

D. Chevalier; A. Le Bail; M. Ghoul

2000-01-01

427

Multifractality and freezing phenomena in random energy landscapes: An introduction  

NASA Astrophysics Data System (ADS)

We start our lectures with introducing and discussing the general notion of multifractality spectrum for random measures on lattices, and how it can be probed using moments of that measure. Then we show that the Boltzmann-Gibbs probability distributions generated by logarithmically correlated random potentials provide a simple yet non-trivial example of disorder-induced multifractal measures. The typical values of the multifractality exponents can be extracted from calculating the free energy of the associated Statistical Mechanics problem. To succeed in such a calculation we introduce and discuss in some detail two analytically tractable models for logarithmically correlated potentials. The first model uses a special definition of distances between points in space and is based on the idea of multiplicative cascades which originated in theory of turbulent motion. It is essentially equivalent to statistical mechanics of directed polymers on disordered trees studied long ago by Derrida and Spohn (1988) in Ref. [12]. In this way we introduce the notion of the freezing transition which is identified with an abrupt change in the multifractality spectrum. Second model which allows for explicit analytical evaluation of the free energy is the infinite-dimensional version of the problem which can be solved by employing the replica trick. In particular, the latter version allows one to identify the freezing phenomenon with a mechanism of the replica symmetry breaking (RSB) and to elucidate its physical meaning. The corresponding one-step RSB solution turns out to be marginally stable everywhere in the low-temperature phase. We finish with a short discussion of recent developments and extensions of models with logarithmic correlations, in particular in the context of extreme value statistics. The first appendix summarizes the standard elementary information about Gaussian integrals and related subjects, and introduces the notion of the Gaussian free field characterized by logarithmic correlations. Three other appendices provide the detailed exposition of a few technical details underlying the replica analysis of the model discussed in the lectures.

Fyodorov, Yan V.

2010-10-01

428

Depression Among Methamphetamine Users  

PubMed Central

Although depression is highly comorbid with substance use disorders, little is known about the clinical course and outcomes of methamphetamine (MA) users with depressive symptoms and syndromes. In this study of MA-dependent individuals entering psychosocial treatment, we predicted that (1) depressive symptoms would decline during treatment, an effect that would vary as a function of MA use and (2) depression diagnoses post-treatment would be associated with poorer outcomes. Participants (N = 526) were assessed for depression, substance use, and psychosocial outcomes at baseline, treatment discharge, and 3-year follow-up. Depressive symptoms declined significantly during treatment, an effect that was greatest among those who abstained from MA. Major depression at follow-up was associated with poorer MA use outcomes and impairment across multiple domains of functioning. The findings highlight the relationship of depressive symptoms and diagnoses to treatment outcomes, and suggest a need for further studies of depression in populations using MA.

Glasner-Edwards, Suzette; Marinelli-Casey, Patricia; Hillhouse, Maureen; Ang, Alfonso; Mooney, Larissa J.; Rawson, Richard

2009-01-01

429

On the size dependence of contact freezing probability  

NASA Astrophysics Data System (ADS)

The contact freezing of supercooled water droplets electrodynamically levitated in the aerosol flow containing clay mineral particles has been investigated in the temperature range from -27°C to -34°C. The aerosol generation system employs a multistage impactor to narrow down the size distribution of aerosol. We use mobility selected illite clay mineral particles of four characteristic diameters to investigate the influence of particle size onto the freezing probability in the contact mode. Our preliminary results show that the contact freezing probability is proportional to the square of particle size (surface area), a feature which is normally attributed to the immersion freezing efficacy of atmospheric ice active particles. Along with the observed temperature and material dependence of contact freezing, this finding provides a new basis for approaching the question of similarity between the contact and immersion freezing.

Kiselev, Alexei; Hoffmann, Nadine; Duft, Denis; Leisner, Thomas

2013-05-01

430

Poststroke Depression: A Review  

PubMed Central

Objective To review the world’s (English-language) publications related to depression following stroke. Method The databases from MEDLINE and PubMed were reviewed for articles related to poststroke depression (PSD), depression and cerebral vascular accident, depression and cerebral vascular disease, and depression and cerebral infarction. Results Most studies examined prevalence rates of depression and the clinical correlates of depression. Based on pooled data, the overall prevalence of major depression was 21.7% and minor depression was 19.5%. The strongest single correlate of depression was severity of impairment in activities of daily living. However, the existence of depression at baseline was found to be associated with greater impairment at follow-up, ranging from 6 weeks to 2 years in 83% of studies. Further, depression following acute stroke was also associated with greater cognitive impairment and increased mortality. PSD has been shown in 6 double-blind controlled studies to be effectively treated with antidepressants, and 1 study has recently shown that PSD can be effectively prevented. Conclusions During the past 20 years, significant progress has been made in the identification and treatment of depression following stroke. In the future, antidepressant treatment will likely play an increasing role in the management of patients with acute stroke. Further research is needed to identify the mechanisms of depression and why antidepressants lead to improved physical and cognitive recovery and decreased mortality.

Robinson, Robert G.; Spalletta, Gianfranco

2013-01-01

431

Infrared freezing of Euclidean QCD observables  

SciTech Connect

We consider the leading one-chain term in a skeleton expansion for QCD observables and show that for energies Q{sup 2}>{lambda}{sup 2}, where Q{sup 2}={lambda}{sup 2} is the Landau pole of the coupling, the skeleton expansion result is equivalent to the standard Borel integral representation, with ambiguities related to infrared (IR) renormalons. For Q{sup 2}<{lambda}{sup 2} the skeleton expansion result is equivalent to a previously proposed modified Borel representation where the ambiguities are connected with ultraviolet (UV) renormalons. We investigate the Q{sup 2}-dependence of the perturbative corrections to the Adler-D function, the GLS sum rule and the polarized and unpolarized Bjorken sum rules. In all these cases the one-chain result changes sign in the vicinity of Q{sup 2}={lambda}{sup 2}, and then exhibits freezing behavior, vanishing at Q{sup 2}=0. Finiteness at Q{sup 2}={lambda}{sup 2} implies specific relations between the residues of IR and UV renormalon singularities in the Borel plane. These relations, only one of which has previously been noted (though it remained unexplained), are shown to follow from the continuity of the characteristic function in the skeleton expansion. By considering the compensation of nonperturbative and perturbative ambiguities we are led to a result for the Q{sup 2}-dependence of these observables at all Q{sup 2}, in which there is a single undetermined nonperturbative parameter, and which involves the skeleton expansion characteristic function. The observables freeze to zero in the infrared. We briefly consider the freezing behavior of the Minkowskian R{sub e{sup +}}{sub e{sup -}} ratio.

Brooks, Paul M.; Maxwell, C. J. [Institute for Particle Physics Phenomenology, University of Durham, South Road, DH1 3LE (United Kingdom)

2006-09-15

432

[Depression and manic-depressive disorders].  

PubMed

The two major subtypes of manic-depressive illness are bipolar disorder and recurrent major depressive disorder. Biological data strongly indicate that a significant genetic factor is involved in the development of manic-depressive illness. But, stressful life events, environmental stress and premorbid personality factors may also be involved in other important etiologic factors. Some research data indicate that cyclothymic disorder and temperamental disorders may be considered as mild forms of bipolar disorders so called "subaffective disorders". The identification of clinical or biological features reflecting the severity of the major depressive episode is very important in regard of the high potential for suicide of the illness. PMID:10337214

Spadone, C; Gallarda, T; Fischman, J; Olié, J P

1999-04-01

433

Strange hadron resonances and QGP freeze-out  

Microsoft Academic Search

We describe how the abundance and distribution of hyperon resonances can be used to probe freeze-out conditions. We demonstrate that resonance yields allow us to measure the time scales of chemical and thermal freeze-outs. This should permit a direct differentiation between the explosive, sudden and staged adiabatic freeze-out scenarios. We then discuss the meaning of recent experimental results and suggest

G. Torrieri; J. Rafelski

2002-01-01

434

Nitrous oxide emissions from soil during freezing and thawing periods  

Microsoft Academic Search

In a laboratory investigation, the processes of N2O emissions during freezing\\/thawing periods were studied. Four undisturbed soil columns from an agricultural site were subjected to two freeze\\/thaw cycles. Two periods of higher N2O emissions were detected, a period of elevated N2O emissions during continuous soil freezing and a period of brief peak emissions during thawing. Soil respiration indicated that microorganisms

R Teepe; R Brumme; F Beese

2001-01-01

435

Spray-freeze-drying production of thermally sensitive polymeric nanoparticle aggregates for inhaled drug delivery: effect of freeze-drying adjuvants.  

PubMed

Inhalable dry-powder aggregates of drug-loaded thermally sensitive poly(caprolactone) (PCL) nanoparticles are produced using spray-freeze-drying (SFD) as the low melting point of PCL prohibits the use of high-temperature spray-drying. The effects of freeze-drying adjuvant formulation on the particle morphology, aerodynamic diameter, aqueous re-dispersibility, flowability, and production yield are examined using mannitol and poly(vinyl alcohol) (PVA) as the adjuvants. The primary role of the adjuvant is to prevent irreversible nanoparticle coalescences during freeze-drying, thereby the nanoparticle aggregates can readily re-disperse into primary nanoparticles in an aqueous environment hence retaining their therapeutic functions. The nanoparticle aggregates produced using either adjuvant exhibit large, porous, and spherical morphologies suitable for dry-powder-inhaler delivery. The nanoparticle aggregates exhibit good flowability and effective aerosolization off the inhaler. The adjuvant selection governs the resultant nanoparticle-adjuvant structures, where PCL nanoparticles are physically dispersed in porous mannitol matrix, whereas PVA are coated onto the nanoparticle surface. Importantly, nanoparticle aggregates produced by SFD exhibit significantly higher aqueous re-dispersibility than those produced by spray-drying, which signifies the suitability of SFD as the method to produce solid-dosage-form of thermally sensitive nanoparticles. Overall, using PVA as adjuvant leads to more stable morphology, superior aqueous re-dispersibility, and higher production yield compared to the mannitol formulation. PMID:21093560

Cheow, Wean Sin; Ng, Mabel Li Ling; Kho, Katherine; Hadinoto, Kunn

2010-11-18

436

Cobalt-Carbon Eutectic Fixed Point for Contact Thermometry  

NASA Astrophysics Data System (ADS)

Two Co-C eutectic fixed points were constructed for thermocouple calibration. The eutectic fixed points were measured with a Pt/Pd thermocouple calibrated at the freezing temperatures of Sn, Zn, Al, Ag, and Au. A temperature of (1323.99 ± 0.52) °C ( k = 2) was determined via this method. The cell design allowed filling to be accomplished in a single step. Each cell was held above 1300 °C for at least 42 h and was subjected to at least 20 melt/freeze cycles with no mechanical failure occurring.

Todd, A. D. W.; Gotoh, M.; Woods, D. J.; Hill, K. D.

2011-01-01

437

In-line multipoint near-infrared spectroscopy for moisture content quantification during freeze-drying.  

PubMed

During the past decade, near-infrared (NIR) spectroscopy has been applied for in-line moisture content quantification during a freeze-drying process. However, NIR has been used as a single-vial technique and thus is not representative of the entire batch. This has been considered as one of the main barriers for NIR spectroscopy becoming widely used in process analytical technology (PAT) for freeze-drying. Clearly it would be essential to monitor samples that reliably represent the whole batch. The present study evaluated multipoint NIR spectroscopy for in-line moisture content quantification during a freeze-drying process. Aqueous sucrose solutions were used as model formulations. NIR data was calibrated to predict the moisture content using partial least-squares (PLS) regression with Karl Fischer titration being used as a reference method. PLS calibrations resulted in root-mean-square error of prediction (RMSEP) values lower than 0.13%. Three noncontact, diffuse reflectance NIR probe heads were positioned on the freeze-dryer shelf to measure the moisture content in a noninvasive manner, through the side of the glass vials. The results showed that the detection of unequal sublimation rates within a freeze-dryer shelf was possible with the multipoint NIR system in use. Furthermore, in-line moisture content quantification was reliable especially toward the end of the process. These findings indicate that the use of multipoint NIR spectroscopy can achieve representative quantification of moisture content and hence a drying end point determination to a desired residual moisture level. PMID:23351045

Kauppinen, Ari; Toiviainen, Maunu; Korhonen, Ossi; Aaltonen, Jaakko; Järvinen, Kristiina; Paaso, Janne; Juuti, Mikko; Ketolainen, Jarkko

2013-02-04

438

The Effect of Freezing on Thylakoid Membranes in the Presence of Organic Acids  

PubMed Central

The effect of salts of organic acids on washed and non-washed chloroplast membranes during freezing was investigated. Thylakoids were isolated from spinach leaves (Spinacia oleracea L.) and, prior to freezing, salts of various organic acids or inorganic salts or both were added. Freezing occurred for 3 to 4 hours at ?25 C. After thawing membrane integrity was investigated by measuring the activity of cyclic photophosphorylation. At very low NaCl levels (1 to 3 mm, washed thylakoids) salts of organic acids either could not prevent membrane inactivation in the course of freezing (succinate) or were effective only at relatively high concentrations (0.1 m or more of acetate, pyruvate, malate, tartrate, citrate). If NaCl was present at higher concentrations (e.g., 0.1 m) some organic acids, e.g. succinate, malate, tartrate, and citrate, were able to protect frost-sensitive thylakoids at surprisingly low concentrations (10 to 20 mm). Other inorganic salts such as KCl, MgCl2, NaNO3 could also induce protection by organic acids which otherwise were ineffective or poorly effective. For effective protection, a more or less constant ratio between inorganic salt and organic acid or between two or more organic acids had to be maintained. Departure to either side from the optimal ratio led to progressive inactivation. The unspecificity of the protective effect of organic acids suggests that these compounds protect colligatively. There are also indications that, in addition, more specific interaction with the membranes contributes to protection. At temperatures above the freezing point, the presence of salts of organic acids decreased the rate of membrane inactivation by high electrolyte concentrations.

Santarius, Kurt A.

1971-01-01

439

On the representation of immersion and condensation freezing in cloud models using different nucleation schemes  

NASA Astrophysics Data System (ADS)

Ice nucleation in clouds is often observed at temperatures >235 K, pointing to heterogeneous freezing as a predominant mechanism. Many models deterministically predict the number concentration of ice particles as a function of temperature and/or supersaturation. Laboratory experiments at constant temperature and/or supersaturation often report heterogeneous freezing as a stochastic, time-dependent process that follows classical nucleation theory which might appear to contradict singular freezing behavior. We explore the extent to which the choice of nucleation scheme (deterministic/stochastic, single/multiple contact angles ?) affects the prediction of the frozen ice nuclei (IN) fraction and cloud evolution. A box model with constant temperature and supersaturation is used to mimic published laboratory experiments of immersion freezing of kaolinite (~243 K), and the fitness of different nucleation schemes. Sensitivity studies show that agreement of all five schemes is restricted to the narrow parameter range (time, temperature, IN diameter) in the original laboratory studies. The schemes are implemented in an adiabatic parcel model that includes feedbacks of the formation and growth of drops and ice particles on supersaturation during the ascent of an air parcel. Model results show that feedbacks of droplets and ice on supersaturation limit ice nucleation events, often leading to smaller differences in number concentration of ice particles and ice water content (IWC) between stochastic and deterministic approaches than expected from the box model studies. However, the different parameterizations of ? distributions and time-dependencies are highly sensitive to IN size and can lead to great differences in predicted ice number concentrations and IWC between the different schemes. Finally, since the choice of nucleation scheme determines the temperature range over which nucleation occurs, at habit-prone temperatures (~253 K) different onset temperatures of freezing create variability in the initial inherent growth ratio of ice particles, which can lead to amplification or reduction in differences in predicted IWC.

Ervens, B.; Feingold, G.

2012-03-01

440

Freezing on heating of liquid solutions.  

PubMed

We report a reversible liquid-solid transition upon heating of a simple solution composed of a-cyclodextrine (alpha CD), water, and 4-methylpyridine. These solutions are homogeneous and transparent at ambient temperature and solidify when heated to temperatures between 45 degrees and 75 degrees. Quasielastic and elastic neutron scattering show that molecular motions are slowed down in the solid and that crystalline order is established. The solution "freezes on heating." This process is fully reversible, on cooling the solid melts. A rearrangement of hydrogen bonds is postulated to be responsible for the observed phenomenon. PMID:15352791

Plazanet, M; Floare, C; Johnson, M R; Schweins, R; Trommsdorff, H P

2004-09-15

441

Freezing on heating of liquid solutions  

NASA Astrophysics Data System (ADS)

We report a reversible liquid-solid transition upon heating of a simple solution composed of a-cyclodextrine (?CD), water, and 4-methylpyridine. These solutions are homogeneous and transparent at ambient temperature and solidify when heated to temperatures between 45° and 75°. Quasielastic and elastic neutron scattering show that molecular motions are slowed down in the solid and that crystalline order is established. The solution ``freezes on heating.'' This process is fully reversible, on cooling the solid melts. A rearrangement of hydrogen bonds is postulated to be responsible for the observed phenomenon.

Plazanet, M.; Floare, C.; Johnson, M. R.; Schweins, R.; Trommsdorff, H. P.

2004-09-01

442

A variant of a slam freezing device for electron microscopy.  

PubMed

A home-made slam freezing device is presented that allows reproducible results in freezing various unfixed tissues. The heart of the device is an aluminum socket, which harbors a plunger that is set in motion by a spring. At the end of the plunger there is an electromagnet which holds the sample on a sheet metal planchette. During stop freezing the electrical contacts are interrupted and the plunger can be withdrawn leaving the specimen on the cooled copper block. This guarantees freezing of not only solid tissues, but also cell suspensions, such as blood or bone marrow. PMID:8148433

Lemke, C; Schwerdtfeger, M; Pöhlmann, I; Sammler, G; Linss, W

1994-01-01

443

Experimental quantification of contact freezing in an electrodynamic balance  

NASA Astrophysics Data System (ADS)

Heterogeneous nucleation of ice in a supercooled water droplet induced by external contact with a dry aerosol particle has long been known to be more effective than freezing induced by the same nucleus immersed in the droplet. However, the experimental quantification of contact freezing is challenging. Here we report an experimental method to determine the temperature-dependent ice nucleation probability of size-selected aerosol particles. The method is based on the suspension of supercooled charged water droplets in a laminar flow of air containing aerosol particles as contact freezing nuclei. The rate of droplet-particle collisions is calculated numerically with account for Coulomb attraction, drag force and induced dipole interaction between charged droplet and aerosol particles. The calculation is verified by direct counting of aerosol particles collected by a levitated droplet. By repeating the experiment on individual droplets for a sufficient number of times, we are able to reproduce the statistical freezing behavior of a large ensemble of supercooled droplets and measure the average rate of freezing events. The freezing rate is equal to the product of the droplet-particle collision rate and the probability of freezing on a single contact, the latter being a function of temperature, size and composition of the contact ice nuclei. Based on these observations, we show that for the types of particles investigated so far, contact freezing is the dominating freezing mechanism on the timescale of our experiment.

Hoffmann, N.; Kiselev, A.; Rzesanke, D.; Duft, D.; Leisner, T.

2013-09-01

444

Anoxia tolerance and freeze tolerance in hatchling turtles.  

PubMed

Freezing survival in hatchling turtles may be limited by ischemic anoxia in frozen tissues and the associated accumulation of lactate and reactive oxygen species (ROS). To determine whether mechanisms for coping with anoxia are also important in freeze tolerance, we examined the association between capacities for freezing survival and anoxia tolerance in hatchlings of seven species of turtles. Tolerance to freezing (-2.5 degrees C) was high in Emydoidea blandingii, Chrysemys picta, Terrapene ornata, and Malaclemys terrapin and low in Graptemys geographica, Chelydra serpentina, and Trachemys scripta. Hatchlings survived in a N(2) atmosphere at 4 degrees C for periods ranging from 17 d (M. terrapin) to 50 d (G. geographica), but survival time was not associated with freeze tolerance. Lactate accumulated during both stresses, but plasma levels in frozen/thawed turtles were well below those found in anoxia-exposed animals. Activity of the antioxidant enzyme catalase in liver increased markedly with anoxia exposure in most species, but increased with freezing/thawing only in species with low freeze tolerance. Our results suggest that whereas oxygen deprivation occurs during somatic freezing, freeze tolerance is not limited by anoxia tolerance in hatchling turtles. PMID:15739066

Dinkelacker, S A; Costanzo, J P; Lee, R E

2005-03-01

445

Freezing and Melting, Precipitation Type, and Numerical Weather Prediction  

NSDL National Science Digital Library

This Webcast, Freezing and Melting, Precipitation Type, and Numerical Weather Prediction, is based on a COMET classroom presentation by Dr. Gary Lackmann at the 2nd MSC Winter Weather Course held in Boulder, Colorado on 22 February 2002. Dr. Lackmann reviews the basic thermodynamics of freezing and melting and how operational models represent these processes. He also touches upon the biases that occur in the models by looking at examples of melting snow aloft, melting snow at the surface, freezing aloft (ice pellets), and freezing rain. Dr. Lackmann is a faculty member in the Department of Marine, Earth, and Atmospheric Sciences at North Carolina State University.

Spangler, Tim

2002-01-01

446

Identification of chaperones in freeze tolerance in Saccharomyces cerevisiae.  

PubMed

Exposure to low temperatures reduces protein folding rates and induces the cold denaturation of proteins. Considering the roles played by chaperones in facilitating protein folding and preventing protein aggregation, chaperones must exist that confer tolerance to cold stress. Here, yeast strains lacking individual chaperones were screened for reduced freezing tolerance. In total, 19 of 82 chaperone-deleted strains tested were more sensitive to freeze-thaw treatment than wild-type cells. The reintroduction of the respective chaperone genes into the deletion mutants recovered the freeze tolerance. The freeze sensitivity of the chaperone-knockout strains was also retained in the presence of 20% glycerol. PMID:23124761

Naicker, Mahendran Chinnamara; Seul Jo, I; Im, Hana

2012-11-04

447

Optical coherence tomography-based freeze-drying microscopy  

PubMed Central

A new type of freeze-drying microscope based upon time-domain optical coherence tomography is presented here (OCT-FDM). The microscope allows for real-time, in situ 3D imaging of pharmaceutical formulations in vials relevant for manufacturing processes with a lateral resolution of <7 ?m and an axial resolution of <5 ?m. Correlation of volumetric structural imaging with product temperature measured during the freeze-drying cycle allowed investigation of structural changes in the product and determination of the temperature at which the freeze-dried cake collapses. This critical temperature is the most important parameter in designing freeze-drying processes of pharmaceutical products.

Mujat, Mircea; Greco, Kristyn; Galbally-Kinney, Kristin L.; Hammer, Daniel X.; Ferguson, R. Daniel; Iftimia, Nicusor; Mulhall, Phillip; Sharma, Puneet; Pikal, Michael J.; Kessler, William J.

2011-01-01

448

Does the cryogenic freezing process cause shorter telomeres?  

PubMed

We have observed evidence of increased telomere shortening in short-term T-lymphocyte cultures following freezing and thawing of the original inoculum obtained by ficoll-paque gradient centrifugation, compared to T-lymphocytes that were cultured immediately without freezing and thawing from the same blood sample from 3 female and 3 male adults. Because freezing may have similar effects on other cell types, and because telomere shortening may only manifest its effects after many years or decades, we suggest there is a pressing need for evaluation of the effects of freezing on any cells envisioned for clinical applications, including embryo implantation. PMID:22465657

Jenkins, Edmund C; Ye, Lingling; Silverman, Wayne P

2012-03-29

449

Possible Application of Bacterial Condensation Freezing to Artificial Rainfall Enhancement.  

NASA Astrophysics Data System (ADS)

Both gram-positive and gram-negative bacteria become excellent condensation nuclei when lyophilized to dryness. The same freeze-dry procedure does not inactivate the highly effective freezing nuclei produced by ice nucleation active bacteria. Therefore, irrespective of their contact nucleation potential, ice nucleation-active bacteria ought to effect condensation freezing at 10°C of warmer in cloud systems. Output from a numerical cloud model suggests that the condensation freezing capability of ice nucleation-active bacteria at warmer temperatures could be exploited to produce rainfall from clouds too warm to respond positively to inorganic nucleants like silver iodide.

Levin, Z.; Yankofsky, S. A.; Pardes, D.; Magal, N.

1987-09-01

450

Reversible Photoinhibition in Antarctic Moss during Freezing and Thawing.  

PubMed

Tolerance of antarctic moss to freezing and thawing stress was investigated using chlorophyll a fluorescence. Freezing in darkness caused reductions in Fv/Fm (ratio of variable to maximum fluorescence) and Fo (initial fluorescence) that were reversible upon thawing. Reductions in Fv/Fm and Fo during freezing in darkness indicate a reduction in the potential efficiency of photosystem II that may be due to conformational changes in pigment-protein complexes due to desiccation associated with freezing. The absorption of light during freezing further reduced Fv/Fm and Fo but was also reversible. Using dithiothreitol (DTT), which inhibits the formation of the carotenoid zeaxanthin, we found reduced flurorescence quenching during freezing and reduced concentrations of zeaxanthin and antheraxanthin after freezing in DTT-treated moss. Reduced concentrations of zeaxanthin and antheraxanthin in DTT-treated moss were partially associated with reductions in nonphotochemical fluorescence quenching. The reversible photoinhibition observed in antarctic moss during freezing indicates the existence of processes that protect from photoinhibitory damage in environments where freezing temperatures occur in conjunction with high solar radiation levels. These processes may limit the need for repair cycles that require temperatures favorable for enzyme activity. PMID:12228644

Lovelock, C. E.; Jackson, A. E.; Melick, D. R.; Seppelt, R. D.

1995-11-01

451

Food freezing with simultaneous surface dehydration: approximate prediction of weight loss during freezing and storage  

Microsoft Academic Search

Weight loss of unpackaged foods during freezing and later storage is an important quality and economic issue. It is originated on surface ice sublimation due to differences in water activity between food surface and the refrigerating air. Weight loss rate is determined by refrigerating conditions and product characteristics. The modelling of this phenomenon has merited very little attention; at present

Laura A. Campañone; Viviana O. Salvadori; Rodolfo H. Mascheroni

2005-01-01

452

Effects of electrode materials on freezing of supercooled water in electric freeze control  

Microsoft Academic Search

In order to clarify effects of electric charge on freezing of supercooled water, experiments were carried out with various kinds of electrodes in supercooled water. Water sample was kept in a test tube and cooled down at a constant cooling rate. When the water sample was maintained under a supercooling state, an electric charge was applied to the water sample

Tsutomu Hozumi; Akio Saito; Seiji Okawa; Kazuharu Watanabe

2003-01-01

453

Effects of shapes of electrodes on freezing of supercooled water in electric freeze control  

Microsoft Academic Search

In order to clarify the effects of electric charge on freezing of supercooled water, experiments were carried out. Two kinds of shapes were used for tips of electrodes. One was the sharp end surface. The other was the flat end surface. Aluminum was selected as the material. Water sample was kept in a test tube and cooled down at a

Tsutomu Hozumi; Akio Saito; Seiji Okawa; Yoichiro Eshita

2005-01-01

454

Effects of Electric and Magnetic Field on Freezing and Possible Relevance in Freeze Drying  

Microsoft Academic Search

Application of an electric or magnetic field can significantly affect the freezing characteristics of water. A DC electric field will tend to induce ice nucleation at a lower degree of supercooling, and there is evidence to show that an AC electric field delays the onset of ice nucleation. Industrial research has shown that a magnetic field can be used to

M. W. Woo; A. S. Mujumdar

2010-01-01

455

High-pressure freezing and freeze substitution of Arabidopsis for electron microscopy.  

PubMed

The objectives of electron microscopy ultrastructural studies are to examine cellular architecture and relate the cell's structural machinery to dynamic functional roles. This aspiration is difficult to achieve if specimens have not been adequately preserved in a "living state"; hence specimen preparation is of the utmost importance for the success of any electron micrographic study. High-pressure freezing (HPF)/freeze substitution (FS) has long been recognized as the primer technique for the preservation of ultrastructure in biological samples. In most cases a basic HPF/freeze substitution protocol is sufficient to obtain superior ultrastructural preservation and structural contrast, which allows one to use more advanced microscopy techniques such as 3D electron tomography. However, for plant tissues, which have a thick cell wall, large water-filled vacuoles, and air spaces (all of which are detrimental to cryopreservation), these basic HPF/FS protocols often yield undesirable results. In particular, ice crystal artifacts and the staining of membrane systems are often poorly or negatively stained, which make 3D segmentation of a tomogram difficult. To overcome these problems, various aspects of the HPF/FS protocol can be altered, including the cryo-filler(s) used, freeze substitution cocktail, and the resin infiltration process. This chapter will describe these modifications for the preparation of plant tissues for routine electron microscopic studies, immunocytochemistry, and 3D tomographic electron imaging. PMID:24057382

Austin, Jotham R

2014-01-01

456

To Freeze or Not to Freeze? An Evolutionary Perspective on the Cold?Hardiness Strategies of Overwintering Ectotherms  

Microsoft Academic Search

We address the question of whether freeze-tolerance, freeze-avoidance, or mixed strategy represents the best adaptation for overwintering ectotherms to endure severe winter. To this end, we develop an optimization fitness model that takes into account different physiological parameters such as energetic level, the phys- iological stress associated with each strategy, and climatic variables. The results show that the freeze-tolerance strategy

Yann Voituron; Nicolas Mouquet; Claire de Mazancourt; Jean Clobert

2002-01-01

457

Morphological study of endothelial cells during freezing  

NASA Astrophysics Data System (ADS)

Microvascular injury is recognized as a major tissue damage mechanism of ablative cryosurgery. Endothelial cells lining the vessel wall are thought to be the initial target of freezing. However, details of this injury mechanism are not yet completely understood. In this study, ECMatrix™ 625 was used to mimic the tumour environment and to allow the endothelial cells cultured in vitro to form the tube-like structure of the vasculature. The influence of water dehydration on the integrity of this structure was investigated. It was found that the initial cell shape change was mainly controlled by water dehydration, dependent on the cooling rate, resulting in the shrinkage of cells in the direction normal to the free surface. As the cooling was prolonged and temperature was lowered, further cell shape change could be induced by the chilling effects on intracellular proteins, and focal adhesions to the basement membrane. Quantitative analysis showed that the freezing induced dehydration greatly enhanced the cell surface stresses, especially in the axial direction. This could be one of the major causes of the final breaking of the cell junction and cell detachment.

Zhang, A.; Xu, L. X.; Sandison, G. A.; Cheng, S.

2006-12-01

458

Morphological study of endothelial cells during freezing.  

PubMed

Microvascular injury is recognized as a major tissue damage mechanism of ablative cryosurgery. Endothelial cells lining the vessel wall are thought to be the initial target of freezing. However, details of this injury mechanism are not yet completely understood. In this study, ECMatrix 625 was used to mimic the tumour environment and to allow the endothelial cells cultured in vitro to form the tube-like structure of the vasculature. The influence of water dehydration on the integrity of this structure was investigated. It was found that the initial cell shape change was mainly controlled by water dehydration, dependent on the cooling rate, resulting in the shrinkage of cells in the direction normal to the free surface. As the cooling was prolonged and temperature was lowered, further cell shape change could be induced by the chilling effects on intracellular proteins, and focal adhesions to the basement membrane. Quantitative analysis showed that the freezing induced dehydration greatly enhanced the cell surface stresses, especially in the axial direction. This could be one of the major causes of the final breaking of the cell junction and cell detachment. PMID:17110769

Zhang, A; Xu, L X; Sandison, G A; Cheng, S

2006-11-02

459

On the Freezing Process with Supercooling  

NASA Astrophysics Data System (ADS)

Experiments and statistical analysis were carried out to study the effect of cooling rate and surface area on freezing temperature of supercooled water attached to a heat transfer surface. Electrolytically polished copper disk was used and experiments were carried out under three kinds of fixed cooling rates (0.05K/s, 0.2K/s & 0.8K/s). In a case of experiments under high cooling rate, non-uniform temperature distribution existed on the surface, so the analytical method introduced in the former paper could not be applied. Hence another method was introduced here. The heat transfer surface was divided into a few parts so that in each part a temperature distribution on the surface kept uniform. The probability for the whole surface was taken as a combination of the probability for each part. By using this method, the probability of ice appearance within a unit surface area in unit time interval was calculated for each series of cooling rate. The results were compared and was observed that the probability of ice appearance was independent of the cooling rate and the area used for the experiment. Hence the reliability of using the method to predict the most probable freezing temperature of supercooled water introduced in this paper was clarified.

Saito, Akio; Okawa, Seiji; Tamaki, Atsushi

460

Immersion freezing of birch pollen washing water  

NASA Astrophysics Data System (ADS)

In the present study, the immersion freezing behavior of birch pollen, i.e. its ice nucleating active (INA) macromolecules, was investigated at the Leipzig Aerosol Cloud Interaction Simulator (LACIS). For that, washing water of two different birch pollen samples with different regional origin (Northern birch and Southern birch) were used. The immersion freezing of droplets generated from the pollen washing water was already observed at temperatures higher than -20 °C, for both samples. Main differences between the Northern birch pollen and the Southern birch pollen were obvious in a temperature range, between -18 °C and -24 °C, where the ice fraction increased with decreasing temperature. There, the Northern birch pollen washing water featured two different slopes, with one being steeper and one being similar to the slope of the Southern birch pollen washing water. As we assume single INA macromolecules being the reason for the ice nucleation, we concluded that the Northern birch pollen are able to produce at least two different types of INA macromolecules. We were able to determine the heterogeneous nucleation rates for both INA macromolecule types and so could explain the ice nucleation behavior of both, the Southern and the Northern birch pollen washing water.

Augustin, S.; Hartmann, S.; Pummer, B.; Grothe, H.; Niedermeier, D.; Clauss, T.; Voigtländer, J.; Tomsche, L.; Wex, H.; Stratmann, F.

2012-12-01

461

Do You Have Major Depression?  

MedlinePLUS

... of this page please turn Javascript on. Feature: Depression Do You Have Major Depression? Past Issues / Fall 2009 Table of Contents Simple ... member may have major depression. —NIMH Types of Depression Just like other illnesses, such as heart disease, ...

462

Major depression with psychotic features  

MedlinePLUS

... depression along with loss of touch with reality (psychosis). See also: Major depression Psychosis ... with psychotic depression have symptoms of depression and psychosis. Psychosis is a loss of contact with reality. ...

463

Clinical and molecular genetics of psychotic depression.  

PubMed

This review provides a comprehensive overview of clinical and molecular genetic as well as pharmacogenetic studies regarding the clinical phenotype of "psychotic depression." Results are discussed with regard to the long-standing debate on categorical vs dimensional disease models of affective and psychotic disorders on a continuum from unipolar depression over bipolar disorder and schizoaffective disorder to schizophrenia. Clinical genetic studies suggest a familial aggregation and a considerable heritability (39%) of psychotic depression partly shared with schizoaffective disorder, schizophrenia, and affective disorders. Molecular genetic studies point to potential risk loci of psychotic depression shared with schizoaffective disorder (1q42, 22q11, 19p13), depression, bipolar disorder, and schizophrenia (6p, 8p22, 10p13-12, 10p14, 13q13-14, 13q32, 18p, 22q11-13) and several vulnerability genes possibly contributing to an increased risk of psychotic symptoms in depression (eg, BDNF, DBH, DTNBP1, DRD2, DRD4, GSK-3beta, MAO-A). Pharmacogenetic studies implicate 5-HTT, TPH1, and DTNBP1 gene variation in the mediation of antidepressant treatment response in psychotic depression. Genetic factors are suggested to contribute to the disease risk of psychotic depression in partial overlap with disorders along the affective-psychotic spectrum. Thus, genetic research focusing on psychotic depression might inspire a more dimensional, neurobiologically and symptom-oriented taxonomy of affective and psychotic disorders challenging the dichotomous Kraepelinian view. Additionally, pharmacogenetic studies might aid in the development of a more personalized treatment of psychotic depression with an individually tailored antidepressive/antipsychotic pharmacotherapy according to genotype. PMID:23512949

Domschke, Katharina

2013-03-19

464

Freezing survival, body ice content and blood composition of the freeze-tolerant European common lizard, Lacerta vivipara.  

PubMed

To investigate the freeze tolerance of the European common lizard, Lacerta vivipara, we froze 17 individuals to body temperatures as low as -4 degrees C under controlled laboratory conditions. The data show that this species tolerates the freezing of 50% of total body water and can survive freezing exposures of at least 24-h duration. Currently, this represents the best known development of freeze tolerance among squamate reptiles. Freezing stimulated a significant increase in blood glucose levels (16.15+/- 1.73 micromol x ml(-1) for controls versus 25.06 +/- 2.92 micromol x ml(-1) after thawing) but this increase had no significant effect on serum osmolality which was unchanged between control and freeze-exposed lizards (506.0 +/- 23.8 mosmol x l(-1) versus 501.0 +/- 25.3 mosmol x l(-1), respectively). Tests that assessed the possible presence of antifreeze proteins in lizard blood were negative. Recovery at 5 degrees C after freezing was assessed by measurements of the mean time for the return of breathing (5.9 +/- 0.5 h) and of the righting reflex (44.8 +/- 4.5 h). Because this species hibernates in wet substrates inoculative freezing may frequently occur in nature and the substantial freeze tolerance of this lizard should play a key role in its winter survival. PMID:11824405

Voituron, Y; Storey, J M; Grenot, C; Storey, K B

2002-01-01

465

Probability of freezing in the freeze-avoiding beetle larvae Cucujus clavipes puniceus (Coleoptera: Cucujidae) from interior Alaska.  

PubMed

Freeze-avoiding insects must resist freezing or die. A suite of adaptations to low temperatures, including the production of antifreeze proteins, colligative antifreezes (polyols), and dehydration allows most individuals to prevent freezing below the lowest ambient temperatures experienced in situ; however, there can be a wide variance in the minimum temperatures that individuals of freeze-avoiding species reach before freezing. We used logistic regression to explore factors that affect this variance and to estimate the probability of freezing in larvae of the freeze-avoiding beetle Cucujus clavipes puniceus. We hypothesized that water content ?0.5 mg mg(-1) dry mass would lead to deep supercooling (avoidance of freezing below -58°C). We found a significant interaction between water content and ambient below-snow temperature and a significant difference between individuals collected from two locations in Alaska: Wiseman and Fairbanks. Individuals collected in Wiseman deep supercooled with greater water content and to a greater range of ambient temperatures than individuals collected in Fairbanks, leading to significantly different lethal water contents associated with 50% probability of freezing. PMID:21550349

Sformo, T; McIntyre, J; Walters, K R; Barnes, B M; Duman, J

2011-04-28

466

Effect of long-term freezing and freeze-thaw cycles on indigenous and inoculated microorganisms in dewatered blackwater.  

PubMed

Wastewater treatment in many Arctic regions is inadequate, even nonexisting. Natural freezing of wastewater in those areas may be beneficial for reduction of microorganisms. The aim of this study was to investigate the effect of long-term freezing, and repeated freezing and thawing, on indigenous coliforms, fecal streptococci, and antibiotic-resistant (AR) bacteria, and inoculated Salmonella Enteriditis and E. coli bacteriophage ?X174 in dewatered blackwater. At the end of the long-term freezing experiment (10 months), an MPN recovery study was done, including the microbial groups that had shown the largest reduction, using tryptone soy broth at incubation temperatures of 10 and 20 °C overnight for the coliforms and AR bacteria, and buffered peptone water at incubation temperature of 37 °C for 18-20 h for Salmonella. Fecal streptococci were more resistant to long-term freezing than the coliform group. Total number of AR bacteria decreased slowly but constantly over the 10-month freezing period. Salmonella rapidly decreased and were nondetectable within a week but exhibited some recovery after 10 months of freezing, whereas limited or no recovery of coliforms and AR-bacteria was detected. Bacteriophages showed limited reduction during the long-term freezing. Repeated freezing and thawing increased the reduction of all tested microbial groups markedly. PMID:23113759

Gunnarsdóttir, Ragnhildur; Müller, Karoline; Jensen, Pernille Erland; Jenssen, Petter Deinboll; Villumsen, Arne

2012-11-05

467

Genetic biomarkers of depression  

PubMed Central

Depression is a term that has been used to describe a variety of ailments, ranging from minor to incapacitating. Clinically significant depression, termed as major depression, is a serious condition characterized not only by depressed mood but also by a cluster of somatic, cognitive, and motivational symptoms. Significant research efforts are aimed to understand the neurobiological as well as psychiatric disorders, and the evaluation of treatment of these disorders is still based solely on the assessment of symptoms. In order to identify the biological markers for depression, we have focused on gathering information on different factors responsible for depression including stress, genetic variations, neurotransmitters, and cytokines and chemokines previously suggested to be involved in the pathophys