Sample records for freezing point depression

  1. FREEZING POINT DEPRESSION OF VARIOUS ICE SLURRIES

    Microsoft Academic Search

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

    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

  2. Study of freezing-point depression of selected food extracts

    SciTech Connect

    Tanaka, Fumihiko [Kagoshima Univ. (Japan). Dept. of Agricultural Systems Engineering; Murata, Satoshi; Habara, Kazuhiro; Amaratunga, K.S.P. [Kyushu Univ., Fukuoka (Japan). Dept. of Agricultural Engineering

    1996-12-31

    The phenomenon of freezing-point depression that accompanies the solute concentration of selected food extracts was investigated to reveal the characteristics of solid-liquid phase equilibrium. The freezing curves of various food extracts did not exhibit ideal solution behavior in the higher concentration range. The experimental data were fitted to new freezing-point depression equations by the method of nonlinear least squares, and the results clearly indicated that the calculated freezing points at various concentrations were in good agreement with the experimental data. Furthermore, by using the determined parameters, the freezing ratio and the activation coefficient were derived.

  3. Interpreting freezing point depression of stearic acid and methyl stearate

    Microsoft Academic Search

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

    2005-01-01

    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

  4. Measurement and data interpretation of the freezing point depression of milks

    Microsoft Academic Search

    Ping Chen; Xiao Dong Chen; Kevin W. Free

    1996-01-01

    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

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

    Microsoft Academic Search

    Donald J. Winzor

    2004-01-01

    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

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

    Microsoft Academic Search

    E. Garry; M. Pest; N. Zamp

    2007-01-01

    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

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

    Microsoft Academic Search

    S. Cantor; T. S. Carlton

    1962-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    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.

  9. The freezing point depression of mammalian tissues in relation to the question of osmotic activity of cell fluid.

    PubMed

    APPELBOOM, J W; BRODSKY, W A; DENNIS, W H; DIAMOND, I; MILEY, J F; REHM, W S

    1956-11-20

    The freezing point depression of freshly excised frozen tissues, pulverized in a hydraulic press or in a mortar, is greater than that of plasma. Even at 0 degrees C. the freezing point depression of such homogenates increases significantly with time. Dilution data indicate that such freezing point data are valid. The presence of intact cells has been shown in smears of tissues pulverized in a mortar, but not in smears of those crushed in a hydraulic press. The osmolarity of various diluent solutions affects the calculated osmotic activity of tissue homogenates presumably because of delayed diffusion between the diluent and cell fluid. With a hypertonic NaCl diluent, spuriously low values of tissue osmotic activity are found from calculations assuming instantaneous mixing between homogenates and diluents. The limitations of data from cryoscopic experiments and from tissue-swelling experiments are discussed in relation to the basic question of whether or not cell fluid is isotonic to extracellular fluid. PMID:13385447

  10. A New Predictive Equation for the Depression in Freezing Points of Multicomponent Aqueous Solutions Conforming to the Linear Isopiestic Relation

    Microsoft Academic Search

    Yu-Feng Hu; Shuan-Shi Fan

    2001-01-01

    The linear isopiestic relation has been used together with a well-known thermodynamic equation to establish a new predictive equation for freezing point depression. This equation can provide predictions for multicomponent solutions conforming to the linear isopiestic relation using only information on the corresponding binary subsystems. The predictive capability of the equation has been tested by comparing with the experimental data

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

    Microsoft Academic Search

    H. Oikawa; K. Murakami

    1989-01-01

    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

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

    SciTech Connect

    Hayashi, K.; Kasza, K.

    2000-05-03

    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 ice slurry cooling system depends very strongly on the characteristics of the individual ice particles in the slurry and, in turn, on the method of ice production. Findings from this study provide guidance on the fluidity and handleability of slurry produced by several methods currently under development and already many achieved.

  13. Self-Association of Nicotinamide in Aqueous Solution: Mass Transport, Freezing-Point Depression, and Partition Coefficient Studies

    Microsoft Academic Search

    William N. Charman; Christine S. C. Lai; Barrie C. Finnin; Barry L. Reed

    1991-01-01

    The steady-state flux (SSF) of nicotinamide from an aqueous donor phase across a model Silastic membrane did not increase proportionally with increasing donor phase concentration. The suspected self-association of the drug in aqueous solution was evaluated by studying the concentration-dependent changes in (i) the molal osmotic coefficient of nicotinamide (freezing-point depression studies) and (ii) the partition coefficient between water and

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

    Microsoft Academic Search

    Bodnar

    1993-01-01

    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

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

    Microsoft Academic Search

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

    1975-01-01

    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

  16. Accuracy of two osmometers on standard samples: electrical impedance technique and freezing point depression technique

    NASA Astrophysics Data System (ADS)

    García-Resúa, Carlos; Pena-Verdeal, Hugo; Miñones, Mercedes; Gilino, Jorge; Giraldez, Maria J.; Yebra-Pimentel, Eva

    2013-11-01

    High tear fluid osmolarity is a feature common to all types of dry eye. This study was designed to establish the accuracy of two osmometers, a freezing point depression osmometer (Fiske 110) and an electrical impedance osmometer (TearLab™) by using standard samples. To assess the accuracy of the measurements provided by the two instruments we used 5 solutions of known osmolarity/osmolality; 50, 290 and 850 mOsm/kg and 292 and 338 mOsm/L. Fiske 110 is designed to be used in samples of 20 ?l, so measurements were made on 1:9, 1:4, 1:1 and 1:0 dilutions of the standards. Tear Lab is addressed to be used in tear film and only a sample of 0.05 ?l is required, so no dilutions were employed. Due to the smaller measurement range of the TearLab, the 50 and 850 mOsm/kg standards were not included. 20 measurements per standard sample were used and differences with the reference value was analysed by one sample t-test. Fiske 110 showed that osmolarity measurements differed statistically from standard values except those recorded for 290 mOsm/kg standard diluted 1:1 (p = 0.309), the 292 mOsm/L H2O sample (1:1) and 338 mOsm/L H2O standard (1:4). The more diluted the sample, the higher the error rate. For the TearLab measurements, one-sample t-test indicated that all determinations differed from the theoretical values (p = 0.001), though differences were always small. For undiluted solutions, Fiske 110 shows similar performance than TearLab. However, for the diluted standards, Fiske 110 worsens.

  17. Theoretical and experimental studies on freezing point depression and vapor pressure deficit as methods to measure osmotic pressure of aqueous polyethylene glycol and bovine serum albumin solutions.

    PubMed

    Kiyosawa, Keitaro

    2003-05-01

    For survival in adverse environments where there is drought, high salt concentration or low temperature, some plants seem to be able to synthesize biochemical compounds, including proteins, in response to changes in water activity or osmotic pressure. Measurement of the water activity or osmotic pressure of simple aqueous solutions has been based on freezing point depression or vapor pressure deficit. Measurement of the osmotic pressure of plants under water stress has been mainly based on vapor pressure deficit. However, differences have been noted for osmotic pressure values of aqueous polyethylene glycol (PEG) solutions measured by freezing point depression and vapor pressure deficit. For this paper, the physicochemical basis of freezing point depression and vapor pressure deficit were first examined theoretically and then, the osmotic pressure of aqueous ethylene glycol and of PEG solutions were measured by both freezing point depression and vapor pressure deficit in comparison with other aqueous solutions such as NaCl, KCl, CaCl(2), glucose, sucrose, raffinose, and bovine serum albumin (BSA) solutions. The results showed that: (1) freezing point depression and vapor pressure deficit share theoretically the same physicochemical basis; (2) theoretically, they are proportional to the molal concentration of the aqueous solutions to be measured; (3) in practice, the osmotic pressure levels of aqueous NaCl, KCl, CaCl(2), glucose, sucrose, and raffinose solutions increase in proportion to their molal concentrations and there is little inconsistency between those measured by freezing point depression and vapor pressure deficit; (4) the osmotic pressure levels of aqueous ethylene glycol and PEG solutions measured by freezing point depression differed from the values measured by vapor pressure deficit; (5) the osmotic pressure of aqueous BSA solution measured by freezing point depression differed slightly from that measured by vapor pressure deficit. PMID:12834836

  18. Calculations of Freezing Point Depression, Boiling Point Elevation, Vapor Pressure and Enthalpies of Vaporization of Electrolyte Solutions by a Modified Three-Characteristic Parameter Correlation Model

    Microsoft Academic Search

    Xinlei Ge; Xidong Wang

    2009-01-01

    A method was proposed for calculating the thermodynamic properties, freezing point depression, boiling point elevation, vapor\\u000a pressure and enthalpy of vaporization for single solute electrolyte solutions, including aqueous and nonaqueous solutions,\\u000a based on a modified three-characteristic-parameter correlation model. When compared with the corresponding literature values,\\u000a the calculated results show that this method gives a very good approximation, especially for 1-1

  19. Initial freezing point of Mozzarella cheese

    Microsoft Academic Search

    Gustavo G. Ribero; Amelia C. Rubiolo; Susana E. Zorrilla

    2007-01-01

    The initial freezing point in unsalted fresh Mozzarella cheese was measured. The influence of the water-soluble solids on the freezing point depression of unsalted Mozzarella cheese was analyzed. Central temperature profiles and the initial freezing point of unsalted cylindrical cheese samples (1cm radius; 3cm height) were determined. A lyophilized aqueous extract of the soluble solids at pH 4.6 was obtained

  20. Theoretical and experimental studies on freezing point depression and vapor pressure deficit as methods to measure osmotic pressure of aqueous polyethylene glycol and bovine serum albumin solutions

    Microsoft Academic Search

    Keitaro Kiyosawa

    2003-01-01

    For survival in adverse environments where there is drought, high salt concentration or low temperature, some plants seem to be able to synthesize biochemical compounds, including proteins, in response to changes in water activity or osmotic pressure. Measurement of the water activity or osmotic pressure of simple aqueous solutions has been based on freezing point depression or vapor pressure deficit.

  1. The nature of aqueous solutions: insights into multiple facets of chemistry and biochemistry from freezing-point depressions.

    PubMed

    Zavitsas, Andreas A

    2010-05-25

    Contrary to current widely held beliefs, many concentrated aqueous solutions of electrolytes and nonelectrolytes behave ideally. For both, the same simple equation yields mole fractions of water that are equal to the theoretical activities of water. No empirical activity coefficients or ad hoc parameters are needed. Thermodynamic hydration numbers and the number of particles produced per mole of solute are found by searching freezing-point depression measurements, as if asking the water, "How much available water solvent is left and how many solute particles are there?" The results answer questions currently under debate: Do solutes alter the nature of water outside their immediate surroundings? What is the number of ion pairs formed by various electrolytes and what affects extents of their formation? What are some factors that cause precipitation of proteins, latexes, and so forth from aqueous solutions upon addition of other solutes (Hofmeister series)? Which nonelectrolytes form aggregates in water and what are the implications? Why do different solutes affect viscosity differently? How do ion-selective channels in cell membranes function at the molecular level? PMID:20397243

  2. Freezing of aqueous solution in a simple apparatus designed for measuring freezing point

    Microsoft Academic Search

    Xiao Dong Chen; Ping Chen

    1996-01-01

    Freezing point depression (FPD) measurement can be used as a fast means of determining solute concentration of an aqueous solution in the laboratory and the data are useful in the process design of low temperature operations, e.g. freeze concentration and freeze drying, etc. It is desirable to have a cost-effective device for FPD measurement. Here, we describe a simple device

  3. New Type of Freezing-Point Apparatus. Freezing Points of Dilute Lanthanum Chloride Solutions

    Microsoft Academic Search

    G. Scatchard; B. Vonnegut; D. W. Beaumont

    1960-01-01

    A new type of freezing-point apparatus is described that reduces the errors of previous types. The freezing-point depressions of aqueous lanthanum chloride solutions up to 0.04 m are adequately expressed by the Debye-Hu¨ckel approximation for ions with a=6.15 A plus a very small linear term. The ``higher terms'' are computed by combining the equations of Mayer and Kirkwood, using the

  4. 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

    Stein, C.L.

    1985-09-01

    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.

  5. 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)

    Inaba, Hideo; Morita, Shin-Ichi

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

  6. 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.)

  7. 7.NS Comparing Freezing Points

    NSDL National Science Digital Library

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Ocean water freezes at about $-2 \\frac12 ^\\circ C$. Fresh water freezes at $0 ^\\circ C$. Antifreeze, a liquid used in the radiators of cars, freezes at...

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

    ERIC Educational Resources Information Center

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

    2007-01-01

    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 quality,…

  9. Device and method for determining freezing points

    NASA Technical Reports Server (NTRS)

    Mathiprakasam, Balakrishnan (Inventor)

    1986-01-01

    A freezing point method and device (10) are disclosed. The method and device pertain to an inflection point technique for determining the freezing points of mixtures. In both the method and device (10), the mixture is cooled to a point below its anticipated freezing point and then warmed at a substantially linear rate. During the warming process, the rate of increase of temperature of the mixture is monitored by, for example, thermocouple (28) with the thermocouple output signal being amplified and differentiated by a differentiator (42). The rate of increase of temperature data are analyzed and a peak rate of increase of temperature is identified. In the preferred device (10) a computer (22) is utilized to analyze the rate of increase of temperature data following the warming process. Once the maximum rate of increase of temperature is identified, the corresponding temperature of the mixture is located and earmarked as being substantially equal to the freezing point of the mixture. In a preferred device (10), the computer (22), in addition to collecting the temperature and rate of change of temperature data, controls a programmable power supply (14) to provide a predetermined amount of cooling and warming current to thermoelectric modules (56).

  10. Improve online freeze and cloud point control

    SciTech Connect

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

    1997-01-01

    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.

  11. Prediction of the freezing point of multicomponent liquid refrigerant solutions

    Microsoft Academic Search

    Héctor A. Tello Alonso; Juan M. Peralta; Amelia C. Rubiolo; Susana E. Zorrilla

    2011-01-01

    The freezing point is one of the most critical properties required to complete the mathematical formulation related to the transport phenomena involved in the immersion chilling and freezing (ICF) of foods. Unfortunately, data for ternary and higher order systems are scarce. The aim of this work was to verify the validity of an excess Gibbs energy model for predicting the

  12. High-freezing-point fuels used for aviation turbine engines

    NASA Technical Reports Server (NTRS)

    Friedman, R.

    1979-01-01

    Broadened-specification aviation fuels could be produced from a greater fraction of crude source material with improvements in fuel supply and price. These fuels, particularly those with increased final boiling temperatures, would have higher freezing temperatures than current aviation turbine fuels. The higher-freezing-point fuels can be substituted in the majority of present commercial flights, since temperature data indicate that in-flight fuel temperatures are relatively mild. For the small but significant fraction of commercial flights where low fuel temperatures make higher freezing-point fuel use unacceptable, adaptations to the fuel or fuel system may be made to accommodate this fuel. Several techniques are discussed. Fuel heating is the most promising concept. One simple system design uses existing heat rejection from the fuel-lubricating oil cooler, another uses an engine-driven generator for electrical heating. Both systems offer advantages that outweigh the obvious penalties.

  13. A Study of Ionic Association in Aqueous Solutions of Bi-Bivalent Electrolytes by Freezing-Point Measurements

    Microsoft Academic Search

    P. G. M. Brown; J. E. Prue

    1955-01-01

    Measurements of freezing-point depression with a precision of ± 0\\\\cdot 0002 degrees C have been made on aqueous solutions of potassium chloride and the sulphates of copper, zinc, magnesium, calcium, cobalt and nickel. The results for the sulphates have been analyzed using the theory of incomplete dissociation in a manner which makes clear the physical status of the dissociation constants

  14. High freezing point fuels used for aviation turbine engines

    NASA Technical Reports Server (NTRS)

    Friedman, R.

    1979-01-01

    Broadened-specification aviation fuels could be produced from a greater fraction of crude source material with improvements in fuel supply and price. These fuels, particularly those with increased final boiling temperatures, would have higher freezing temperatures than current aviation turbine fuels. For the small but significant fraction of commercial flights where low fuel temperatures make higher freezing-point fuel use unacceptable, adaptations to the fuel or fuel system may be made to accommodate this fuel. Several techniques are discussed. Fuel heating is the most promising concept. One simple design uses existing heat rejection from the fuel-lubricating oil cooler, another uses an engine-driven generator for electrical heating.

  15. STUDIES ON THE PHYSICAL STATE OF WATER IN LIVING CELLS AND MODEL SYSTEMS. IV. FREEZING AND THAWING POINT DEPRESSION OF WATER BY GELATIN, OXYGEN-CONTAINING POLYMERS AND UREA-DENATURED PROTEINS

    Microsoft Academic Search

    G. N. LING; Z. L. ZHANG

    Using a differential scanning calorimeter, we studied the freezing and thawing behavior of solutions of six globular proteins (hemoglobin, bovine serum albumin, y-globulin, P- lactoglobulin, egg albumin, and protamine sulfate); gelatin; and three synthetic polymers (polyvinylpyrrolidone (PVP), polyvinylmethylether (PVME), andpoly(ethy1ene oxide) (PEO)). The native globular proteins in concentrations up to 50% produced no major change of the freezing temperature of

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

    Microsoft Academic Search

    Robert J. Baer; Kirk A. Baldwin

    1984-01-01

    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

  17. Phase separation of quaternary solubilized solutions or micro emulsion of hydrocarbons containing sodium oleate + phenol + benzene + water by freezing point measurements

    Microsoft Academic Search

    Bhagwan Swaroop

    1978-01-01

    Summary The depressions in freezing point measurements in quaternary solubilized solutions or micro-emulsion in sodium oleate + phenol + benzene + water are measured. Maxima and minima were observed, Gibbs' phase rule was applicable, eutectic points were detected, congruent melting points were obtained, loose combination of molecules or clusters, were formed, phases of the system transferred and finally unstable emulsion

  18. Open Zinc Freezing-Point Cell Assembly and Evaluation

    NASA Astrophysics Data System (ADS)

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

    2014-07-01

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

  19. 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

    Quentin D. Craft; W. Alexander Hook

    1975-01-01

    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

  20. [Depressive pseudodementia. Differential diagnosis or meeting point?].

    PubMed

    Richly, Pablo; Abdulhamid, Pablo; Bustin, Julián

    2012-01-01

    Depressive pseudodementia is a major depressive disorder in which the cognitive deficits secondary to the affective disorder is so significant that clinicians are obliged to consider dementia as a differential diagnosis. The relationship between depression and dementia is complex and intricate. Even after depressive pseudodementia has remitted, certain cognitive deficits may persist and the risk of developing dementia increases. The concept of depressive pseudodementia continues to be useful in clinical practice in spite of its limitations. PMID:23979551

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

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

    SciTech Connect

    Tavener, J. P.; Tavener, S. J.; Tavener, I. F.; Davies, N. [Isothermal Technology Ltd (Isotech), Pine Grove, Southport, Merseyside, PR9 9AG, England (United Kingdom)] [Isothermal Technology Ltd (Isotech), Pine Grove, Southport, Merseyside, PR9 9AG, England (United Kingdom)

    2013-09-11

    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.

  3. Freezing-Point Depressions of Hoagland's `Carbowax' Systems

    Microsoft Academic Search

    Howard G. Applegate

    1960-01-01

    SOLUTIONS of various osmotic pressures have been widely used in biology. Sugars and their derivatives, commonly used to maintain osmotic pressures, have the drawback that many, if not all, of these compounds can be metabolized by the test tissue or organism. McClenden and Blinks1 described the use of `Carbowax 4000' (polyethylene glycol) in maintaining various osmotic concentrations in a study

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

    NASA Technical Reports Server (NTRS)

    Pasion, A. J.

    1979-01-01

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

  5. Fuel freeze-point investigations. Final report, September 1982-March 1984

    SciTech Connect

    Desmarais, L.A.; Tolle, F.F.

    1984-07-01

    The objective of this program was to conduct a detailed assessment of the low-temperature environment to which USAF aircraft are exposed for the purpose of defining a maximum acceptable fuel freeze-point and also to define any operational changes required with the use of a high freeze-point fuel. A previous study of B-52, C-141, and KC-135 operational missions indicated that the -58 C freeze point specification was too conservative. Based on recommendations resulting from the previous program, several improvements in the method of analysis were made, such as: expansion of the atmospheric temperature data base, the addition of ground temperature analysis, the addition of fuel-freezing analysis to the one-dimensional fuel-temperature computer program, and the examination of heat transfer in external fuel tanks, such as pylon or tip tanks. The B-52, C-141, and KC-135 mission were analyzed again, along with the operational missions of two tactical airplanes, the A-10 and F-15; -50C was determined to be the maximum allowable freeze point for a general-purpose USAF aviation turbine fuel. Higher freeze points can be tolerated if the probability of operational interference is acceptably low or if operational changes can be made. Study of atmospheric temperatures encountered for the missions of the five-study aircraft indicates that a maximum freeze point of -48 C would not likely create any operational difficulties in Northern Europe.

  6. When hot water freezes before cold

    Microsoft Academic Search

    J. I. Katz

    2009-01-01

    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

  7. When hot water freezes before cold

    Microsoft Academic Search

    J. I. Katz

    2006-01-01

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

  8. Fuel freeze-point investigations. Final report, September 1982March 1984

    Microsoft Academic Search

    L. A. Desmarais; F. F. Tolle

    1984-01-01

    The objective of this program was to conduct a detailed assessment of the low-temperature environment to which USAF aircraft are exposed for the purpose of defining a maximum acceptable fuel freeze-point and also to define any operational changes required with the use of a high freeze-point fuel. A previous study of B-52, C-141, and KC-135 operational missions indicated that the

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

    Microsoft Academic Search

    J A Ramsay; R H J Brown

    1955-01-01

    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

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

    Microsoft Academic Search

    Amos Banin; Duwayne M. Anderson

    1974-01-01

    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

  11. Tender points, depressive and functional symptoms: comparison between fibromyalgia and major depression.

    PubMed

    Fassbender, K; Samborsky, W; Kellner, M; Müller, W; Lautenbacher, S

    1997-01-01

    The degree of symptomatic overlap between fibromyalgia and major depression should be estimated by assessing the amount of local tenderness and the frequency and severity of depressive and functional symptoms. Tender points were assessed by palpation and symptoms by psychometric scales in 30 patients with fibromyalgia and 26 patients with major depression. The patients with fibromyalgia had markedly more tender points (16.5) than the depressive patients (1.3). In contrast, depressive and functional symptoms were present in both groups of patients, and some depressive patients (26%) also suffered from clinical pain. An increased sensitivity to pressure pain clearly distinguishes fibromyalgia from depression even if there is an overlap of other symptoms. PMID:9132330

  12. Freezing points and enthalpies of dilution of aqueous formic, acetic, propionic, and butyric acids. Free energies and enthalpies of solute—Solute interactions

    Microsoft Academic Search

    Alexander L. Harris; Peter T. Thompson; Robert H. Wood

    1980-01-01

    Freezing-point depressions and enthalpies of dilution for aqueous solutions of the straight chain, aliphatic carboxylic acids, C1 through C4, have been measured. These data, together with the corresponding apparent molal heat capacities, have been used to calculate the pairwise free energy and enthalpy of interaction of undissociated acid molecules at 298.150K. As expected, the effect of dimer and triplet interaction

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

    NASA Astrophysics Data System (ADS)

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

    2012-06-01

    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.

  14. Evaluation of methods for rapid determination of freezing point of aviation fuels

    NASA Technical Reports Server (NTRS)

    Mathiprakasam, B.

    1982-01-01

    Methods for identification of the more promising concepts for the development of a portable instrument to rapidly determine the freezing point of aviation fuels are described. The evaluation process consisted of: (1) collection of information on techniques previously used for the determination of the freezing point, (2) screening and selection of these techniques for further evaluation of their suitability in a portable unit for rapid measurement, and (3) an extensive experimental evaluation of the selected techniques and a final selection of the most promising technique. Test apparatuses employing differential thermal analysis and the change in optical transparency during phase change were evaluated and tested. A technique similar to differential thermal analysis using no reference fuel was investigated. In this method, the freezing point was obtained by digitizing the data and locating the point of inflection. Results obtained using this technique compare well with those obtained elsewhere using different techniques. A conceptual design of a portable instrument incorporating this technique is presented.

  15. 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)

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

    2008-06-01

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

  16. Point-prevalence of depression and associated risk factors.

    PubMed

    Richards, Derek; Sanabria, Alicia Salamanca

    2014-01-01

    The study aimed to assess levels of depressive symptoms and associated risk factors in a sample of students in Bogotá, Colombia. A convenient sample (N = 254) of students at the University Antonio Nariño, Bogotá was invited to complete an online survey that contained questions associated with common risk factors for depression and the Beck Depression Inventory (BDI-II). Chi-square was used to analyze comparisons between demographic and risk factors and severity of depression, and comparisons between those depressed and not depressed. Odds Ratios and their 95% confidence interval (95% CI) were computed through logistic regression model developed for each independent variable. The point-prevalence of current depressive symptoms was 36.2%; women 47.3% and men 21.3%. Risk factors associated with depression included being a woman, having a previous diagnosis, suicidal ideation and (or) intent, sleep problems, a recent loss, and a history of family depression and alcoholism. The study confirms the high incidence of depression and associated risk factors in students. The results demonstrate a need for prevention measures, early detection and early intervention. PMID:24839729

  17. Critical viewpoints on the methods of realizing the metal freezing points of the ITS-90

    NASA Astrophysics Data System (ADS)

    Ma, C. K.

    1995-08-01

    The time-honored method for realizing the freezing point tf of a metal (in practice necessarily a dilute alloy) is that of continuous, slow freezing where the plateau temperature (which is the result of solidifying material's being so pure that its phase-transition temperature is observably constant) is measured. The freezing point being an equilibrium temperature, Ancsin considers this method to be inappropriate in principle: equilibrium between the solid and liquid phases cannot be achieved while the solid is being cooled to dispose of the releasing latent heat and while it is accreting at the expense of the liquid. In place of the continuous freezing method he has employed the pulse-heating method (in which the sample is allowed to approach equilibrium after each heat pulse) in his study of Ag; his measurements suggest that freezing can produce non-negligible errors. Here we examine both methods and conclude that the freezing method, employing an inside solid-liquid interface thermally isolated by an outside interface, can provide realizations of the highest accuracy; in either method, perturbation, by inducing solid-liquid phase transition continuously or intermittently, is essential for detecting equilibrium thermally. The respective merits and disadvantages of these two methods and also of the inner-melt method are discussed. We conclude that in a freezing-point measurement what is being measured is in effect the however minutely varying phase transition, and nonconstitutional equilibrium, temperature ti at the solid-liquid interface. The objective is then to measure the ti that is the best measure of tf, which is, normally, the plateau temperature.

  18. Nano materials for efficiently lowering the freezing point of heat transfer nanofluids

    Microsoft Academic Search

    Haiping Hong; Walter Roy

    2007-01-01

    In this paper, we report, for the first time, the effect of the lowered freezing point in a 50% water \\/ 50% antifreeze coolant (PAC) or 50% water \\/ 50% ethylene glycol (EG) solution by the addition of carbon nanotubes and other particles. The experimental results indicated that the nano materials are much more efficient (hundreds fold) in lowering the

  19. Influence of Vacuum Pasteurization upon the Freezing Point Value, Total Solids, and Concentration of Fluid Milk

    Microsoft Academic Search

    J. T. Lazar Jr.; R. W. Henningson

    1960-01-01

    SUMMARY The concentration of milk due to pasteurization in a Vacu-Therm pasteurizer was estimated by freezing point measurements, total solids determinations, and by condensing and trapping the water removed from the milk. Composite samples of raw and pasteurized milk were obtained during 3-hr. processing periods from the balance and surge tanks of the equipment. The temperature of pasteurization and the

  20. Relationship Between Ice Nucleation Temperature Depression and Equilibrium Melting Points Depression of Medaka (Oryzias latipes) Embryos

    NASA Astrophysics Data System (ADS)

    Kimizuka, Norihito; Suzuki, Toru

    We measured the ice nucleation temperature depression , ?Tf , and equilibrium melting points depression, ?Tm, of Medaka (Oryzias latipes) embryos with different cryoprotectant (ethylene glycol, 1.3-propanediol, 1.4-butanediol, glycerol aqueous solutions) treatments. Our obtained results showed the good relationship between the ?Tf ,and ?Tm all samples. In addition the value of ? , which can be obtained from the linear relationship, ?Tf =? ?Tm, were confirmed to show correlation with the value of ? , as obtained by the W/O emulsion method.

  1. A Four-Zone Furnace for Realization of Silver and Gold Freezing Points

    NASA Astrophysics Data System (ADS)

    Ripple, D. C.; Garrity, K. M.; Meyer, C. W.

    2003-09-01

    Recently, the Thermocouple Calibration Laboratory at the National Institute of Standards and Technology has used sodium heat-pipe furnaces for the realization of ITS-90 freezing points of aluminum, silver, and gold. When using a fixed-point cell mounted in a long silica-glass tube that extends to ambient temperature at the top of the furnace, we have observed significant thermal gradients along the well of the fixed-point cell, with the top of the well up to 0.1 K colder than the bottom. Furthermore, the heat-pipe lifetime is limited when used at the gold point (1064.18 °C) for more than a few hundred hours. To address these problems, we have designed and built a four-zone furnace based on a temperature-controlled, graphite isothermal block, suspended inside a three-zone tube furnace. The three-zone furnace is of a commercial design. The graphite block is enclosed in an alloy 600 (Inconel) can, allowing the graphite to be maintained in an argon atmosphere. The argon pressure is maintained at one atmosphere at all temperatures, thereby greatly reducing the stress on the can. Heaters in intimate contact with the can allow temperature control of the fourth inner zone to high accuracy. In this paper, the measured thermal stability and uniformity achieved with this furnace are presented. We also give results of test freezes of a silver freezing-point cell.

  2. When hot water freezes before cold

    NASA Astrophysics Data System (ADS)

    Katz, J. I.

    2009-01-01

    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 heated, reducing the temperature of the freezing front, and thereby reducing the temperature gradient and heat flux, slowing the progress of the freezing front. I present a simple calculation of this effect, and suggest experiments to test this hypothesis.

  3. Freezing Ice

    NSDL National Science Digital Library

    Francis Eberle

    2007-01-01

    The purpose of this assessment probe is to elicit students' ideas about freezing point. The probe is designed to find out whether students recognize that water freezes at the same time independent of the volume of water.

  4. The Evaluation of the Emissivity and the Temperature of Cavities at the Gold Freezing Point

    NASA Astrophysics Data System (ADS)

    Hongpan, Chen; Shouren, Chen; Zaixiang, Chu

    1981-04-01

    In the present investigation, the integral equation for the temperature distribution inside the cavity at the gold freezing point, and the relation between the emissivity and the local temperature have been derived according to the basic ideas of Geist. In addition, we have calculated the changes of the temperature and emissivity of the bottom of a baffled cylindrical cavity due to the changes in the temperature of the baffle. Some typical results are given here.

  5. Bovine serum albumin: survival and osmolarity effect in bovine spermatozoa stored above freezing point.

    PubMed

    Nang, C F; Osman, K; Budin, S B; Ismail, M I; Jaffar, F H F; Mohamad, S F S; Ibrahim, S F

    2012-05-01

    Liquid nitrogen preservation in remote farms is a limitation. The goal of this study was to determine optimum temperature above freezing point for bovine spermatozoa preservation using bovine serum albumin (BSA) as a supplementation. Pooled semen sample from three ejaculates was subjected to various BSA concentration (1, 4, 8 and 12 mg ml(-1)), before incubation in different above freezing point temperatures (4, 25 and 37 °C). Viability assessment was carried out against time from day 0 (fresh sample) until all spermatozoa become nonviable. Optimal condition for bovine spermatozoa storage was at 4 °C with 1 mg ml(-1) BSA for almost 7 days. BSA improved bovine spermatozoa viability declining rate to 44.28% at day 4 and 57.59% at day 7 compared to control, with 80.54% and 98.57% at day 4 and 7 respectively. Increase in BSA concentration did not improve sperm viability. Our results also confirmed that there was a strong negative correlation between media osmolarity and bovine spermatozoa survival rate with r = 0.885, P < 0.0001. Bovine serum albumin helps to improve survival rate of bovine spermatozoa stored above freezing point. PMID:21806660

  6. Freezing Models For Heterogeneous Drop Freezing In Immersion and Contact Modes

    Microsoft Academic Search

    K. Diehl; S. Wurzler

    2002-01-01

    Field measurements showed that supercooled liquid water drops and frozen drops can coexist in tropospheric clouds at temperatures down to -40 C with an incidence of ice particles already at -4 C. The freezing behaviour of water drops depends on their sizes, on their content of soluble particles (freezing point depression) and of insoluble particles (potential immersion ice nuclei) as

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

    E-print Network

    Allen, Leslie H.

    Melting point depression of Al clusters generated during the early stages of film growth in microelectronics: i melt- ing point depression as related to the Al reflow process,7­10 ii coalescence during been learned about the size-dependent melting point depression in recent times. Studies in model

  8. Development of modulated optical transmission system to determinate the cloud and freezing points in biofuels.

    PubMed

    Jaramillo-Ochoa, Liliana; Ramirez-Gutierrez, Cristian F; Sánchez-Moguel, Alonso; Acosta-Osorio, Andrés; Rodriguez-Garcia, Mario E

    2015-01-01

    This work is focused in the development of a modulated optical transmission system with temperature control to determine the thermal properties of biodiesels such as the cloud and freezing points. This system is able to determine these properties in real time without relying on the operator skills as indicated in the American Society for Testing Materials (ASTM) norms. Thanks to the modulation of the incident laser, the noise of the signal is reduced and two information channels are generated: amplitude and phase. Lasers with different wavelengths can be used in this system but the sample under study must have optical absorption at the wavelength of the laser. PMID:25638112

  9. Development of modulated optical transmission system to determinate the cloud and freezing points in biofuels

    NASA Astrophysics Data System (ADS)

    Jaramillo-Ochoa, Liliana; Ramirez-Gutierrez, Cristian F.; Sánchez-Moguel, Alonso; Acosta-Osorio, Andrés; Rodriguez-Garcia, Mario E.

    2015-01-01

    This work is focused in the development of a modulated optical transmission system with temperature control to determine the thermal properties of biodiesels such as the cloud and freezing points. This system is able to determine these properties in real time without relying on the operator skills as indicated in the American Society for Testing Materials (ASTM) norms. Thanks to the modulation of the incident laser, the noise of the signal is reduced and two information channels are generated: amplitude and phase. Lasers with different wavelengths can be used in this system but the sample under study must have optical absorption at the wavelength of the laser.

  10. Considerations for osmolality measurement under elevated pCO(2): comparison of vapor pressure and freezing point osmometry.

    PubMed

    Schmelzer, A E; deZengotita, V M; Miller, W M

    2000-01-20

    Osmolality increases with pCO(2) in bioreactors with pH control, and it has been shown that osmolality compensation by decreasing the basal NaCl concentration partially mitigates the adverse effects of elevated pCO(2) on animal cell growth, protein production, and glycosylation. Thus, measurement of osmolality is important for a complete characterization of the culture environment under elevated pCO(2). However, osmolality measurement may be compromised by CO(2) evolution. Freezing point depression and vapor pressure depression osmometry were directly compared for the measurement of osmolality in samples at elevated pCO(2) (up to 250 mmHg) and at a variety of pH values (6.7-7.5). More extensive degassing may be expected with the vapor pressure osmometer due to the smaller sample volume and larger surface area employed. However, both types of osmometer yielded similar results for all pCO(2) and pH values studied. Moreover, the measured values agreed with osmolality values calculated using a semi-empirical model. Further analysis showed that, while sample degassing may result in a large decrease in pCO(2), there is little associated decrease in osmolality. The great majority of total CO(2) in solution is present as bicarbonate (HCO(3)(-)). Although a small amount of HCO(3)(-) is converted to CO(2) to compensate for CO(2) evolution, further depletion of HCO(3)(-) is inhibited by the associated increase in medium pH and by the need for HCO(3)(-) to maintain charge neutrality in solution. This explanation is consistent with the observed similarity in osmolality values for the two types of osmometer. It was also observed that osmolality did not change in samples that were frozen at -20 degrees C for up to 1 year. PMID:10592516

  11. Different cutoff points for different trimesters? The use of Edinburgh Postnatal Depression Scale and Beck Depression Inventory to screen for depression in pregnant Taiwanese women

    Microsoft Academic Search

    Kuan-Pin Su; Tsan-Hung Chiu; Chieh-Liang Huang; Ming Ho; Chieh-Chung Lee; Po-Lun Wu; Cher-Yeang Lin; Chun-Hui Liau; Chin-Chih Liao; Wei-Che Chiu; Carmine M. Pariante

    2007-01-01

    ObjectiveValidating self-reported questionnaires to detect depression during pregnancy, compared to depression during postpartum, has gained much less attention. Furthermore, it is unknown whether it is appropriate to use the same cutoff point to detect depression on different trimesters of pregnancy. The aims of this study, conducted in pregnant Taiwanese women, were: (a) to validate the Taiwanese version of the Edinburgh

  12. Prospective Chemistry Teachers' Misconceptions about Colligative Properties: Boiling Point Elevation and Freezing Point Depression

    ERIC Educational Resources Information Center

    Pinarbasi, Tacettin; Sozbilir, Mustafa; Canpolat, Nurtac

    2009-01-01

    This study aimed at identifying prospective chemistry teachers' misconceptions of colligative properties. In order to fulfill this aim, a diagnostic test composed of four open-ended questions was used. The test was administered to seventy-eight prospective chemistry teachers just before qualifying to teaching in secondary schools. Nine different…

  13. When hot water freezes before cold

    E-print Network

    J. I. Katz

    2006-04-27

    I suggest that the origin of the Mpemba effect (the freezing of hot water before cold) is freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. They are concentrated ahead of the freezing front by zone refining in water that has not been heated, reduce the temperature of the freezing front, and thereby reduce the temperature gradient and heat flux, slowing the progress of the front. I present a simple calculation of this effect, and suggest experiments to test this hypothesis.

  14. When hot water freezes before cold

    E-print Network

    Katz, J I

    2006-01-01

    I suggest that the origin of the Mpemba effect (the freezing of hot water before cold) is freezing-point depression by solutes, either gaseous or solid, whose solubility decreases with increasing temperature so that they are removed when water is heated. They are concentrated ahead of the freezing front by zone refining in water that has not been heated, reduce the temperature of the freezing front, and thereby reduce the temperature gradient and heat flux, slowing the progress of the front. I present a simple calculation of this effect, and suggest experiments to test this hypothesis.

  15. Depression of melting point for protective aluminum oxide films

    NASA Astrophysics Data System (ADS)

    Dreizin, E. L.; Allen, D. J.; Glumac, N. G.

    2015-01-01

    The protective aluminum oxide film naturally formed on a surface of aluminum has a thickness in the range of 3-5 nm. Its melting causes loss of its continuity, which may significantly affect the ignition and combustion processes and their relative time scales. Melting of the alumina film also plays an important role when aluminum powders are used to prepare composites and/or being sintered. This letter quantifies depression of the melting point of an alumina film based on its nano-meter thickness. A theoretical estimate is supported by experiments relying on a detected change in the optical properties of naturally oxidized aluminum particles heated in an inert environment.

  16. Salting out of alcohols by alkali halides at the freezing temperature

    Microsoft Academic Search

    Jacques E. Desnoyers; Michel Billon; Sylvain Léger; Gérald Perron; Jean-Pierre Morel

    1976-01-01

    The freezing-point depression of the ternary systems water-alkali halidesalcohols was measured with a precision Advanced Instrument osmometer. From the corresponding freezing-point depression of the binary systems the salting-out constantsks were calculated. The effect of ionic size was investigated withtert-butanol, and the effect of alcohol chain length with NaCl. The trends ofks with ionic size are similar to those of typical

  17. Final report for the APMP.T-K4: Comparison of realizations of aluminium freezing-point temperatures

    NASA Astrophysics Data System (ADS)

    Gam, K. S.; Joung, W.; Yamazawa, K.; Cheung, C. P.; Y Kho, H.; Wang, L.; Tsai, S. F.; Norranim, U.; Hafidzah, O.; Gupta, J. K.

    2013-01-01

    The comparison APMP.T-K4 is the regional extension of the CCT-K4: an intercomparison of the realizations of the freezing-points of Al (660.323 °C) and Ag (961.78 °C). The comparison was organized in two loops and four sub-loops with high temperature standard platinum resistance thermometers (HTSPRTs) as transfer thermometers in the freezing-point comparisons. The comparison involved eight APMP NMIs (KRISS, NMIJ, SCL, NMC, CMS, NIMT, SIRIM, NPL), and KRISS and NMIJ acted as linking laboratories to the CCT-K4. The transfer HTSPRTs showed a strong drift during the transportation between the NMIs. In the case of the Ag freezing-point comparison, the comparison results were scattered much more than expected. In the APMP meeting held in 2009, the participants agreed that the Ag comparison results would be omitted in the report. It revealed that the measurement results at the Al freezing-point of participants were in agreement with the key comparison reference value of the CCT-K4 within 4 mK except for one laboratory. Details of the comparison results, the uncertainty evaluation and the drift of the HTSPRTs are described in this report. 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 (CIPM MRA).

  18. Working and Non-Working University Students: Anxiety, Depression, and Grade Point Average

    ERIC Educational Resources Information Center

    Mounsey, Rebecca; Vandehey, Michael A.; Diekhoff, George M.

    2013-01-01

    This study explored the differences between 110 working and non-working students in terms of mental health, academic achievement, and perceptions about student employment. Anxiety and depression were measured by the Beck Anxiety Inventory and the Beck Depression Inventory-II. Academic achievement was measured by grade point average. Perceptions of…

  19. Supercooling Point Plasticity During Cold Storage in the Freeze-tolerant Sugarbeet Root Maggot Tetanops myopaeformis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sugarbeet root maggot, Tetanops myopaeformis (Röder), overwinters as a freeze-tolerant 3rd instar larva. While most larvae are thought to overwinter for only one year, some may exhibit prolonged diapause in the field. In the laboratory, they can live for over five years using a combination of ...

  20. Depression

    MedlinePLUS

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

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

    SciTech Connect

    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

    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, .

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

    Microsoft Academic Search

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

    \\u000a Free energy perturbation Monte Carlo (FEP\\/MC) simulations are performed for both the liquid and solid phases of water to determine\\u000a the melting temperature of several popular three and four-site water models. Gibbs free energy vs. temperature plots are constructed\\u000a from the simulations to determine the melting temperature. For the liquid phase, standard FEP\\/MC simulations are used to calculate\\u000a the free

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

    Microsoft Academic Search

    R. Schneppenheim; H. Theede

    1982-01-01

    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

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

    Microsoft Academic Search

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

    2010-01-01

    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

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

    PubMed

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

    2007-11-01

    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

  6. Depression

    MedlinePLUS

    ... and negative thinking worse. Back Continue Depression Can Go Unrecognized People with depression may not realize they ... themselves or who have eating disorders or who go through extreme mood changes may have unrecognized depression. ...

  7. Depression Treatment for Impoverished Mothers by Point-of-Care Providers: A Randomized Controlled Trial

    PubMed Central

    Segre, Lisa S.; Brock, Rebecca L.; O’Hara, Michael W.

    2015-01-01

    Objective Depression in low-income, ethnic-minority women of childbearing age is prevalent and compromises infant and child development. Yet numerous barriers prevent treatment delivery. Listening Visits (LV), an empirically supported intervention developed for delivery by British home-visiting nurses, could address this unmet mental health need. This randomized controlled trial evaluated the effectiveness of LV delivered at a woman’s usual point-of-care, including home-visits or an ob-gyn office. Method Listening Visits were delivered to depressed pregnant women or mothers of young children by their point-of-care provider (e.g., home visitor or physician’s assistant), all of whom had low levels of prior counseling experience. Three quarters of the study’s participants were low-income. Of those who reported ethnicity, all identified themselves as minorities. Participants from four study sites (N = 66) were randomized in a 2:1 ratio, to LV or a wait-list control group (WLC). Assessments, conducted at baseline and 8 weeks, evaluated depression, quality of life, and treatment satisfaction. Results Depressive severity, depressive symptoms, and quality of life significantly improved among LV recipients as compared to women receiving standard social/health services. Women valued LV as evidenced by their high attendance rates and treatment satisfaction ratings. Conclusions In a stepped model of depression care, LV can provide an accessible, acceptable, and effective first-line treatment option for at-risk women who otherwise are unlikely to receive treatment. PMID:25486371

  8. Depression, posttraumatic stress disorder, and grade point average among student servicemembers and veterans.

    PubMed

    Bryan, Craig J; Bryan, AnnaBelle O; Hinkson, Kent; Bichrest, Michael; Ahern, D Aaron

    2014-01-01

    The current study examined relationships among self-reported depression severity, posttraumatic stress disorder (PTSD) symptom severity, and grade point average (GPA) among student servicemembers and veterans. We asked 422 student servicemembers and veterans (72% male, 86% Caucasian, mean age = 36.29 yr) to complete an anonymous online survey that assessed self-reported GPA, depression severity, PTSD severity, and frequency of academic problems (late assignments, low grades, failed exams, and skipped classes). Female respondents reported a slightly higher GPA than males (3.56 vs 3.41, respectively, p = 0.01). Depression symptoms (beta weight = -0.174, p = 0.03), male sex (beta weight = 0.160, p = 0.01), and younger age (beta weight = 0.155, p = 0.01) were associated with lower GPA but not PTSD symptoms (beta weight = -0.040, p = 0.62), although the interaction of depression and PTSD symptoms showed a nonsignificant inverse relationship with GPA (beta weight = -0.378, p = 0.08). More severe depression was associated with turning in assignments late (beta weight = 0.171, p = 0.03), failed exams (beta weight = 0.188, p = 0.02), and skipped classes (beta weight = 0.254, p = 0.01). The relationship of depression with self-reported GPA was mediated by frequency of failed examns. Results suggest that student servicemembers and veterans with greater emotional distress also report worse academic performance. PMID:25436619

  9. Evaluation of Effect of Polymeric Pour Point Depressant Additives on Indian Waxy Crude Oil

    Microsoft Academic Search

    S. Deshmukh; D. Bharambe

    2009-01-01

    Wax deposition in oil production constitutes a critical and difficult-to-control problem in terms of productivity and production operation costs going from the reservoir to surface facilities. In the present work, four polymeric additives were prepared and used as pour point depressants (PPD) for Limbodara (Indian) crude oil via polymerization of different undecylenates with maleic anhydride with a further reaction with

  10. Depression

    MedlinePLUS

    ... causes depression? Depression may be caused by an imbalance of chemicals in the brain. Sometimes there aren' ... and dopamine (say: “dope-a-mean”). A chemical imbalance in the brain may be caused by one ...

  11. 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 ...

  12. The influence of ionizable and non-ionizable compounds in milk upon its freezing point

    E-print Network

    Pinkerton, Frank

    1955-01-01

    fulfillmeut of tho requireaoais for the degree of MAST@a OP SCIXSCS August 1955 Ma)or Sub)sots Dairp Husbaadry TRX I?PLURKCX OF IOWIKEBLD LSD WOX~IOSISLDLX COMPOOTDS IR MILT UPON ITS FSNIWO POIDT k Thesis By Prank P taker ton ipprovs4 as to style an4... Coat Laotose an4 Coaduotivity. The Iafluenoo of Breed on the Preesiag Point of Milk, Por Coat Laotose aa4 Coaduotivity. The Iaf lessee of Type of Ration Ped to Cows upoa ths Pressing Point, Per Coat Lsotose and Conduotivity of Milk. . . . 13 Patt 1...

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

    PubMed Central

    RÄISÄNEN, MIKKO; REPO, TAPANI; LEHTO, TARJA

    2006-01-01

    • 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. PMID:16464880

  14. A NOTE ON THE FREEZING-POINTS OF THE URINES OF TWO FRESH-WATER FISHES: THE CATFISH (AMEIURUS NEBULOSUS@ AND THE SUCKER (CATOSTOMUS COMMERSONI1)

    Microsoft Academic Search

    CHARLOTTE HAYWOOD; MARY JEANNE CLAPP

    In his book, Osmotic Regulation in Aquatic Animals, Krogh (1939) comments on the scarcity of available data for the osmotic concentra tion of the urines of fresh-water fishes. Since such data are appar ently not available for two of our common local forms, the catfish (Ameiurus nebulosus) and the sucker (Catostomus commersonii), we have been interested to make freezing-point determinations

  15. High-speed Imaging of Freezing Drops: Investigating the Role of Point-like Contact in Heterogeneous Ice Nucleation

    NASA Astrophysics Data System (ADS)

    Gurganus, C.; Charnawskas, J.; Shaw, R. A.; Kostinski, A. B.

    2013-12-01

    Formation of ice by contact nucleation remains enigmatic and the possible role of the three-phase boundary (i.e., liquid water-ice-aerosol contact line) is still undetermined. Because aerosol size, surface area, composition and exact region of contact remain difficult to measure, we examine a simpler geometry with a spherical cap droplet resting on a substrate. In this configuration, the droplet simultaneously experiences a two-phase immersion region and a three phase contact region around the perimeter of the droplet. Utilizing high speed imaging of the droplet-substrate plane, we are able to identify nucleation sites in individual droplets. This technique allows for a spatial distribution of freezing sites in addition to a freezing temperature distribution. Our initial study indicated no preference for nucleation originating at the three phase boundary for an atomically smooth homogenous substrate [1]. The nucleation site distribution agreed well with the stochastic view in that the germ sites are distributed uniformly over the surface area. In that study we minimized the thermal variation (?T) across a droplet during cooling to prevent biased observations. We also compared ?T for several experiments in literature using a simple formulation of droplet size (r) and cooling rate (?). Large variations in some experiments could possibly explain observed 'contact nucleation' events in the laboratory as artifacts of radial thermal variations during droplet cooling. As a continuation of this study, we redesigned our system to enable much greater substrate cooling rates, but these experiments too revealed no preference for nucleation in the contact mode. Thermal modeling of the new system confirmed that while a vertical thermal gradient does develop within the droplet, no horizontal gradient is induced in the drop near the substrate. This result argues against a thermodynamic bias toward contact nucleation in substrate cooled geometries. Another possible explanation for this contact phenomenon comes in a lowering of the energy barrier for nucleation due to the existence of a line tension at the point of contact. A scale analysis of the line and surface energy values available in the literature suggests that line tension may become dominant below length scales of ~10 nm [1]. From this simple result we postulate that 'point-like' surface features might play an important role at the three phase boundary. To mimic these features on substrates we introduce chemical and mechanical processes to enhance substrate surface roughness. Using these new substrates we repeat our experimental procedure to compare effectiveness of the immersion (two phase) and contact (three phase) regions for a variety of surface topologies. Here we report the initial findings from this work. 1. Gurganus, C.; Kostinski, A. B.; Shaw, R. A., Fast Imaging of Freezing Drops: No Preference for Nucleation at the Contact Line. J Phys Chem Lett 2011, 2 (12) Identifying nucleation sites with two high speed cameras.

  16. Depression

    MedlinePLUS

    ... go for treatment. Treating Depression Your doctor or mental health expert can often treat your depression successfully. Different therapies seem to work for different people. For instance, support groups can provide new coping skills or social support if you are dealing with a major ...

  17. Freezing in confined geometries

    NASA Technical Reports Server (NTRS)

    Sokol, P. E.; Ma, W. J.; Herwig, K. W.; Snow, W. M.; Wang, Y.; Koplik, Joel; Banavar, Jayanth R.

    1992-01-01

    Results of detailed structural studies, using elastic neutron scattering, of the freezing of liquid O2 and D2 in porous vycor glass, are presented. The experimental studies have been complemented by computer simulations of the dynamics of freezing of a Lennard-Jones liquid in narrow channels bounded by molecular walls. Results point to a new simple physical interpretation of freezing in confined geometries.

  18. Depression.

    PubMed

    Weissman, Myrna

    2009-04-01

    This is an invited article on how my career as an epidemiologist studying depression unfolded. The role of the Civil Rights movement in opening the PhD doors to women at Yale began my career. The unfolding of depression studies are described. These studies included a clinical trial of medication and what later was known as interpersonal psychotherapy (IPT), the first community survey of psychiatric disorder, family genetic and brain imaging studies or depression and anxiety disorders. I hope the new generation will have the wonderful opportunities I have had. PMID:19344866

  19. Size-dependent melting point depression of nanostructures: Nanocalorimetric measurements M. Zhang, M. Yu. Efremov, F. Schiettekatte, E. A. Olson, A. T. Kwan, S. L. Lai, T. Wisleder,

    E-print Network

    Allen, Leslie H.

    Size-dependent melting point depression of nanostructures: Nanocalorimetric measurements M. Zhang in terms of existing melting point depression models. Excellent agreement with the homogeneous melting depression--small particles have a lower melting point than bulk material.3­5 This results from the increas

  20. Prediction of heat capacity, density and freezing point of liquid refrigerant solutions using an excess Gibbs energy model

    Microsoft Academic Search

    Juan M. Peralta; Amelia C. Rubiolo; Susana E. Zorrilla

    2007-01-01

    Immersion chilling and freezing (ICF) of foods use aqueous solutions at low temperature that are considered secondary refrigerants. These solutions contain solutes such as NaCl, CaCl2, KCl, ethanol, glucose, etc. The ICF processes have several advantages over the conventional food chilling and freezing methods. The aim of this work was to study the behavior of an excess Gibbs energy model

  1. Depression

    Microsoft Academic Search

    Jim Nuovo

    \\u000a \\u000a \\u000a \\u000a \\u000a 1. \\u000a \\u000a Depression is one of the most common chronic diseases you will see in your clinic. It affects approximately 20 million Americans.\\u000a \\u000a \\u000a \\u000a 2. \\u000a \\u000a The lifetime prevalence of depression in the general population is 16%.\\u000a \\u000a \\u000a \\u000a 3. \\u000a \\u000a Depression is more likely to occur in patients who have chronic medical problems. Your patients with diabetes, heart failure,\\u000a osteoarthritis, and stroke have 1 1\\/2

  2. Study on performance mechanism of pour point depressants with differential scanning calorimeter and X-ray diffraction methods

    Microsoft Academic Search

    Jinli Zhang; Chuanjie Wu; Wei Li; Yiping Wang; Zhenting Han

    2003-01-01

    Adding pour point depressants (PPD) to lower the Cold Filter Plugging Point (CFPP) of diesel fuels is an effective and economic way of improving the cold flow properties of the oils. EVAP is a new type of PPD and has an excellent effect in lowering the CFPP of most Chinese diesel fuels. To further the development of this PPD product,

  3. Depression

    NSDL National Science Digital Library

    Patient Education Institute

    This patient education program explains depression, the symptoms, causes and available treatment options. This is a MedlinePlus Interactive Health Tutorial from the National Library of Medicine, designed and developed by the Patient Education Institute. NOTE: The tutorial requires a special Flash plug-in, version 4 or above. If you do not have Flash, you will be prompted to obtain a free download of the software before you start the tutorial. You will also need an Acrobat Reader, available as a free download, in order to view the Reference Summary.

  4. Experimental and analytical investigation of a freezing point depressant fluid ice protection system. M.S. Thesis. Final Report

    NASA Technical Reports Server (NTRS)

    Albright, A. E.

    1984-01-01

    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 solutions were evaluated. Minimum glycol flow rates required for anti-icing were obtained as a function of angle of attack, liquid water content, volume median drop diameter, temperature, and velocity. Ice accretions formed after five minutes of icing were shed in three minutes or less using a glycol fluid flow equal to the anti-ice flow rate. Two methods of predicting anti-ice flow rates are presented and compared with a large experimental data base of anti-ice flow rates over a wide range of icing conditions. The first method presented in the ADS-4 document typically predicts flow rates lower than the experimental flow rates. The second method, originally published in 1983, typically predicts flow rates up to 25 percent higher than the experimental flow rates. This method proved to be more consistent between wing-panel configurations. Significant correlation coefficients between the predicted flow rates and the experimental flow rates ranged from .867 to .947.

  5. Freezing lake

    NSDL National Science Digital Library

    Powell, Adam C., IV

    2005-02-23

    Finite difference solution to mixed conduction-convection limited freezing of a 10 cm thick pool of water, with benchmark against analytical timescales. Requisite software: Gnumeric or Excel to open spreadsheets in source directory.

  6. Immobilization and melting point depression of imidazolium ionic liquids on the surface of nano-SiOx particles.

    PubMed

    Liu, Yusheng; Wu, Guozhong; Fu, Haiying; Jiang, Zheng; Chen, Shimou; Sha, Maolin

    2010-04-01

    Four kinds of imidazolium-based ionic liquids (ILs) were immobilized onto the surface of nano-SiO(x) particles (d approximately 20 nm) by grinding in an agate mortar to produce a series of weight ratios of ionic liquid to nanoparticles. The physicochemical properties of immobilized ILs were investigated by differential scanning calorimetry, powder X-ray diffraction and Raman spectroscopy. It was found that the melting points (T(m)) of the immobilized ILs depressed significantly in comparison with the bulk ionic liquids. The T(m) depressions are 10, 12, 13 and 41 degrees C for [EMIM][PF(6)], [PMIM][PF(6)], [PHMIM][BF(4)] and [EMIM][I], respectively, for a loading amount of 35 wt% ionic liquid. The T(m) depression of [EMIM][PF(6)] was independent of the weight proportion of immobilized ionic liquid up to 50 wt%, indicating that nano-SiO(x) has a large capacity for immobilized ILs. The T(m) depression of [EMIM][I] is particularly significant because the H-bonding interactions of iodine anions with surface silanol groups of nano-SiO(x) particles is much weaker than that of fluorine anions with silanol groups of other investigated ionic liquids. PMID:20449446

  7. Liquidus Temperature Depression in Cryolitic Melts

    NASA Astrophysics Data System (ADS)

    Solheim, Asbjørn

    2012-08-01

    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-}.

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

    ERIC Educational Resources Information Center

    Gidron, Yori; Alon, Shirly

    2007-01-01

    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…

  9. Freezing points and enthalpies of dilute aqueous solutions of tetrahydropyran, 1,3-dioxane, 1,4-dioxane, and 1,3,5-trioxane. Free energies and enthalpies of solute-solute interactions

    Microsoft Academic Search

    Byron Y. Okamoto; Robert H. Wood; Jacques E. Desnoyers; Gérald Perron; Lyne Delorme

    1981-01-01

    The enthalpies of dilute aqueous solutions of tetrahydropyran, 1,3-dioxane, 1,4-dioxane, 1,2,5-trioxane, and an equimolal mixture of tetrahydropyran and 1,3,5-trioxane were measured at 25°C and at molalities from about 0.1 to 1.0 mol kg1. The freezing points of the same aqueous solutions (except for 1,3-dioxane) were measured over a similar molality range. The results were used to calculate the enthalpies and

  10. Stability against freezing of aqueous solutions on early Mars

    NASA Astrophysics Data System (ADS)

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

    2009-05-01

    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.

  11. 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

    Tellinghuisen, Joel

    2010-01-01

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

  12. Molecular biology of freezing tolerance.

    PubMed

    Storey, Kenneth B; Storey, Janet M

    2013-07-01

    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

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

    PubMed

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

    2008-02-01

    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

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

    PubMed

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

    2009-05-01

    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

  15. Fundamentals of freeze-drying.

    PubMed

    Nail, Steven L; Jiang, Shan; Chongprasert, Suchart; Knopp, Shawn A

    2002-01-01

    Given the increasing importance of reducing development time for new pharmaceutical products, formulation and process development scientists must continually look for ways to "work smarter, not harder." Within the product development arena, this means reducing the amount of trial and error empiricism in arriving at a formulation and identification of processing conditions which will result in a quality final dosage form. Characterization of the freezing behavior of the intended formulation is necessary for developing processing conditions which will result in the shortest drying time while maintaining all critical quality attributes of the freeze-dried product. Analysis of frozen systems was discussed in detail, particularly with respect to the glass transition as the physical event underlying collapse during freeze-drying, eutectic mixture formation, and crystallization events upon warming of frozen systems. Experiments to determine how freezing and freeze-drying behavior is affected by changes in the composition of the formulation are often useful in establishing the "robustness" of a formulation. It is not uncommon for seemingly subtle changes in composition of the formulation, such as a change in formulation pH, buffer salt, drug concentration, or an additional excipient, to result in striking differences in freezing and freeze-drying behavior. With regard to selecting a formulation, it is wise to keep the formulation as simple as possible. If a buffer is needed, a minimum concentration should be used. The same principle applies to added salts: If used at all, the concentration should be kept to a minimum. For many proteins a combination of an amorphous excipient, such as a disaccharide, and a crystallizing excipient, such as glycine, will result in a suitable combination of chemical stability and physical stability of the freeze-dried solid. Concepts of heat and mass transfer are valuable in rational design of processing conditions. Heat transfer by conduction--the dominant mechanism of heat transfer in freeze-drying--is inefficient at the pressures used in freeze-drying. Steps should be taken to improve the thermal contact between the product and the shelf of the freeze dryer, such as eliminating metal trays from the drying process. Quantitation of the heat transfer coefficient for the geometry used is a useful way of assessing the impact of changes in the system such as elimination of product trays and changes in the vial. Because heat transfer by conduction through the vapor increases with increasing pressure, the commonly held point of view that "the lower the pressure, the better" is not true with respect to process efficiency. The optimum pressure for a given product is a function of the temperature at which freeze-drying is carried out, and lower pressures are needed at low product temperatures. The controlling resistance to mass transfer is almost always the resistance of the partially dried solids above the submination interface. This resistance can be minimized by avoiding fill volumes of more than about half the volume of the container. The development scientist should also recognize that very high concentrations of solute may not be appropriate for optimum freeze-drying, particularly if the resistance of the dried product layer increases sharply with concentration. Although the last 10 years has seen the publication of a significant body of literature of great value in allowing development scientists and engineers to "work smarter," there is still much work needed in both the science and the technology of freeze-drying. Scientific development is needed for improving analytical methodology for characterization of frozen systems and freeze-dried solids. A better understanding of the relationship between molecular mobility and reactivity is needed to allow accurate prediction of product stability at the intended storage temperature based on accelerated stability at higher temperatures. This requires that the temperature dependence of glass transition-associated mobili

  16. Freezing and anoxia tolerance of slugs: a metabolic perspective

    Microsoft Academic Search

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

    2007-01-01

    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

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

    PubMed

    Packard, Gary C; Packard, Mary J

    2004-08-01

    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

  18. Fish With Nature's Anti-freeze

    NSDL National Science Digital Library

    Using this material, students will discover that under special experimental conditions, fish have been observed functioning in ice-free cold salt water at a temperature of -6 degrees Centigrade. Research has found that these fish have eight types of anti-freeze molecules which bathe the interior surface of their skin, acting as a barrier to ice propagating in from outside. When the anti-freeze molecules are not present, ice filters through their skin at these temperatures and crystallizes (freezes) their blood and tissues. Students will experiment with lowering the freezing point of a substance, thus causing it to remain liquid at a temperature when it is normally solid. Students will compare their findings with facts about Antarctic ice-fish, which have bodily fluids that remain liquid at temperatures below freezing.

  19. Freezing precipitation in the Southeastern United States

    E-print Network

    Young, William Robert

    1978-01-01

    'un?I. . . . 2. Developmsnt. , 3. I, ocaticn of freezing prsci. pitation areas. '? ~ 4 ~ ~ ~ ? 26 ?5 25 30 32 32 33 36 38 38 39 43 44 46 47 TABLE OF CONTENTS (Continued) Page IVr ANALYSI S OF P~ERS FOR SELECTED STORMS a ~ ~ ~ ~ ~ ~ 52 Ai... farms) over a range of 850-mb temperature. s ('C) . ~ ~ ~ ~ ~ ~ ~ ~ s ~ ~ ~ ~ 63 Th number of occurrences of freezing pre ipita- tion (varicrus forms) over a range of 850-mb dcw points {'0). ~ 64 25 The number of occur ences of freezing precipita...

  20. Compression of cooked freeze-dried carrots

    E-print Network

    Macphearson, Bruce Alan

    1973-01-01

    ~ order interactions for the attributes mentioned above. From these ~ interactions and correlation coefficients it is evident that some compromises must be made during processing to obtain a quality freese- ' ~ dried compressed carrot bar. The most... LIST OF FIGURES Figure Page 1 Triple point of water Compressed freeze-dried carrot bars Compression cell 12 13 Score card for sensory evaluation of freeze-dried carrot bars . 17 First order interaction of sugar x moisture and shedding time...

  1. The importance of COâ on freezing point measurements of fluid inclusions: evidence from active geothermal systems and implications for epithermal ore deposition

    Microsoft Academic Search

    J. W. Hedenquist; R. W. Henley

    1985-01-01

    The authors show how the melting point of ice may be calculated for a fluid of known composites. Fluid inclusion ice-melting data from New Zealand geothermal fields correlate well with values calculated using the equation presented and the measured compositions of discharges from wells from which the inclusion samples were obtained. Loss of the dominant dissolved gas, COâ during boiling

  2. 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/ ...

  3. The Freezing Bomb

    ERIC Educational Resources Information Center

    Mills, Allan

    2010-01-01

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

  4. Freeze drying apparatus

    DOEpatents

    Coppa, Nicholas V. (Malvern, PA); Stewart, Paul (Youngstown, NY); Renzi, Ernesto (Youngstown, NY)

    2001-01-01

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

  5. Freeze drying method

    DOEpatents

    Coppa, Nicholas V. (Malvern, PA); Stewart, Paul (Youngstown, NY); Renzi, Ernesto (Youngstown, NY)

    1999-01-01

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

  6. Surface freezing of n-octane nanodroplets

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

    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.

  7. 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.

  8. Theory of freezing in simple systems

    SciTech Connect

    Cerjan, C.; Bagchi, B.

    1985-03-01

    The transition parameters for the freezing of two one-component liquids into crystalline solids are evaluated by two theoretical approaches. The first system considered is liquid sodium which crystallizes into a body-centered-cubic (bcc) lattice; the second system is the freezing of adhesive hard spheres into a face-centered-cubic (fcc) lattice. Two related theoretical techniques are used in this evaluation: One is based upon a recently developed bifurcation analysis; the other is based upon the theory of freezing developed by Ramakrishnan and Yussouff. For liquid sodium, where experimental information is available, the predictions of the two theories agree well with experiment and each other. The adhesive-hard-sphere system, which displays a triple point and can be used to fit some liquids accurately, shows a temperature dependence of the freezing parameters which is similar to Lennard-Jones systems. At very low temperature, the fractional density change on freezing shows a dramatic increase as a function of temperature indicating the importance of all the contributions due to the triplet direction correlation function. Also, we consider the freezing of a one-component liquid into a simple-cubic (sc) lattice by bifurcation analysis and show that this transition is highly unfavorable, independent of interatomic potential choice. The bifurcation diagrams for the three lattices considered are compared and found to be strikingly different. Finally, a new stability analysis of the bifurcation diagrams is presented.

  9. Improved freezing level retrieval

    E-print Network

    Hong, Sungwook

    2002-01-01

    TRMM Microwave Imager(TMI)-based passive microwave retrieval techniques result in biased estimates of the freezing level and rainfall over the east Pacific in the Inter Tropical Convergence Zone (ITCZ). Passive microwave rainfall estimates...

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

    NSDL National Science Digital Library

    New England Aquarium

    2011-01-01

    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.

  11. Thermosiphon solar water heater having freeze rupture protection

    Microsoft Academic Search

    1986-01-01

    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

  12. Two-dimensional freezing criteria for crystallizing colloidal monolayers

    SciTech Connect

    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

    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.

  13. H, not O or pressure, causes eutectic T depression in the Fe-FeS System to 8 GPa

    NASA Astrophysics Data System (ADS)

    Buono, Antonio S.; Walker, David

    2015-04-01

    The Fe-FeS system maintains a eutectic temperature of 990 ± 10 °C to at least 8 GPa if starting materials and pressure media are rigorously dehydrated. Literature reports of pressure-induced freezing point depression of the eutectic for the Fe-FeS system are not confirmed. Modest addition of oxygen alone is confirmed to cause negligible freezing point depression at 6 GPa. Addition of H alone causes a progressive decrease in the eutectic temperature with P in the Fe-FeS-H system to below 965 °C at 6 GPa to below 950 °C at 8 GPa. It is our hypothesis that moisture contamination in unrigorously dried experiments may be an H source for freezing point depression. O released from H2O disproportionation reacts with Fe and is sequestered as ferropericlase along the sample capsules walls, leaving the H to escape the system and/or enter the Fe-FeS mixture. The observed occurrence of ferropericlase on undried MgO capsule margins is otherwise difficult to explain, because an alternate source for the oxygen in the ferropericlase layer is difficult to identify. This study questions the use of pressure-depressed Fe-S eutectic temperatures and suggests that the lower eutectic temperatures sometimes reported are achieved by moving into the ternary Fe-S-H system. These results adjust slightly the constraints on eutectic temperatures allowed for partly solidified cores on small planets. H substantially diminishes the temperature extent of the melting interval in Fe-S by reducing the melting points of the crystalline phases more than it depresses the eutectic.

  14. Percolation with Constant Freezing

    NASA Astrophysics Data System (ADS)

    Mottram, Edward

    2014-06-01

    We introduce and study a model of percolation with constant freezing ( PCF) where edges open at constant rate , and clusters freeze at rate independently of their size. Our main result is that the infinite volume process can be constructed on any amenable vertex transitive graph. This is in sharp contrast to models of percolation with freezing previously introduced, where the limit is known not to exist. Our interest is in the study of the percolative properties of the final configuration as a function of . We also obtain more precise results in the case of trees. Surprisingly the algebraic exponent for the cluster size depends on the degree, suggesting that there is no lower critical dimension for the model. Moreover, even for , it is shown that finite clusters have algebraic tail decay, which is a signature of self organised criticality. Partial results are obtained on , and many open questions are discussed.

  15. Freezing of Lennard-Jones-type fluids

    SciTech Connect

    Khrapak, Sergey A. [Max-Planck-Institut fuer Extraterrestrische Physik, D-85741 Garching (Germany); Joint Institute for High Temperatures, 125412 Moscow (Russian Federation); Chaudhuri, Manis; Morfill, Gregor E. [Max-Planck-Institut fuer Extraterrestrische Physik, D-85741 Garching (Germany)

    2011-02-07

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

  16. Avoidance and tolerance of freezing in ectothermic vertebrates.

    PubMed

    Costanzo, Jon P; Lee, Richard E

    2013-06-01

    Ectothermic vertebrates have colonized regions that are seasonally or perpetually cold, and some species, particularly terrestrial hibernators, must cope with temperatures that fall substantially below 0°C. Survival of such excursions depends on either freeze avoidance through supercooling or freeze tolerance. Supercooling, a metastable state in which body fluids remain liquid below the equilibrium freezing/melting point, is promoted by physiological responses that protect against chilling injury and by anatomical and behavioral traits that limit risk of inoculative freezing by environmental ice and ice-nucleating agents. Freeze tolerance evolved from responses to fundamental stresses to permit survival of the freezing of a substantial amount of body water under thermal and temporal conditions of ecological relevance. Survival of freezing is promoted by a complex suite of molecular, biochemical and physiological responses that limit cell death from excessive shrinkage, damage to macromolecules and membranes, metabolic perturbation and oxidative stress. Although freeze avoidance and freeze tolerance generally are mutually exclusive strategies, a few species can switch between them, the mode used in a particular instance of chilling depending on prevailing physiological and environmental conditions. PMID:23678097

  17. Dynamical Interpretation of Chemical Freeze-Out Parameters

    E-print Network

    V. D. Toneev; J. Cleymans; E. G. Nikonov; K. Redlich; A. A. Shanenko

    1999-04-17

    It is shown that the condition for chemical freeze-out, average energy per hadron approximately 1 GeV, selects the softest point of the equation of state, namely the point where the pressure divided by the energy density has a minimum. The sensitivity to the equation of state used is discussed. The previously proposed mixed phase model, which is consistent with lattice QCD data naturally leads to the chemical freeze-out condition.

  18. Freezing Poultry for Home Use

    E-print Network

    Davis, Michael

    2006-08-31

    Purchasing fresh poultry in large packages and freezing it in quantities suitable for individual meals can stretch time and food dollars. Topics include packaging needs, cutting, storing and thawing instructions, and freezing pre-cooked meals....

  19. Animal Anti-Freeze

    NSDL National Science Digital Library

    2012-06-26

    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.

  20. Freeze Branding Horses

    E-print Network

    Householder, Doug; Webb, Gary; Wigington, Sam; Bruemmer, Jason

    2001-06-29

    , simpli- f_ied drawing of one hair shaft with its color (pigment) producing follicle (CF) and its growth follicle (GF), both shown below the skin. Doug Householder 1 , Gary Webb 2 , Sam Wigington 3 and Jason Bruemmer 4 Freeze Branding Horses Figure 1. Hair...

  1. Modeling Soil Freezing Dynamics

    Microsoft Academic Search

    G. N. Flerchinger; M. S. Seyfried; S. P. Hardegree

    2002-01-01

    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 permeability of the soil. This is aggravated by the tendency of water

  2. 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...

  3. 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)

    Pokhodun, A. I.

    2010-01-01

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

  4. Depression, diet and exercise.

    PubMed

    Jacka, Felice N; Berk, Michael

    2013-09-16

    Unhealthy lifestyle behaviour is driving an increase in the burden of chronic non-communicable diseases worldwide. Recent evidence suggests that poor diet and a lack of exercise contribute to the genesis and course of depression. While studies examining dietary improvement as a treatment strategy in depression are lacking, epidemiological evidence clearly points to diet quality being of importance to the risk of depression. Exercise has been shown to be an effective treatment strategy for depression, but this is not reflected in treatment guidelines, and increased physical activity is not routinely encouraged when managing depression in clinical practice. Recommendations regarding dietary improvement, increases in physical activity and smoking cessation should be routinely given to patients with depression. Specialised and detailed advice may not be necessary. Recommendations should focus on following national guidelines for healthy eating and physical activity. PMID:25370279

  5. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

  6. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

  7. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

  8. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 3 2011-01-01 2011-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  9. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 3 2012-01-01 2012-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  10. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 3 2013-01-01 2013-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  11. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 3 2014-01-01 2014-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  12. 7 CFR 58.621 - Freezing tunnels.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 3 2010-01-01 2010-01-01 false Freezing tunnels. 58.621 Section 58.621 Agriculture...Service 1 Rooms and Compartments § 58.621 Freezing tunnels. Freezing tunnels for quick freezing at extremely low...

  13. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

  14. 9 CFR 590.534 - Freezing facilities.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...590.534 Freezing facilities. (a) Freezing rooms, either on or off the premises, shall be capable of freezing all liquid egg products in accordance with the freezing requirements as set forth in §...

  15. Postpartum depression

    MedlinePLUS

    Depression - postpartum; Postnatal depression; Postpartum psychological reactions ... The exact causes of postpartum depression are unknown. Changes in hormone levels during and after pregnancy may affect a woman’s mood. Many non-hormonal factors may also ...

  16. Freezing and anoxia tolerance of slugs: a metabolic perspective.

    PubMed

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

    2007-11-01

    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 circumscriptus. The introduced species showed very poor freezing survival. Supercooling points of the introduced species were quite high ( approximately -3 degrees C) and their freezing survival was very poor, limited to short-term freezing at -1.2 to -1.5 degrees C and low ice contents (23-44%). D. laeve showed a significant elevation of supercooling point between slugs collected in the autumn (-4.8 degrees C +/- 0.5) and those collected early in the spring (-3.1 degrees C +/- 0.4). This species also showed substantial freezing survival which was greater for spring-collected slugs (100% survival of 1 h freezing at -2 degrees C with an ice content of 65%) than for autumn animals (100% survival for 1 h at -1 degrees C with approximately 40% ice). Carbohydrate and amino acid responses to freezing and anoxia exposures were compared in the two Deroceras species. D. laeve showed a strong hyperglycemic response to freezing, a 100-fold increase in glucose levels that suggested that glucose may have a cryoprotective function in this species. D. reticulatum did not accumulate glucose and neither species produced glycerol or lactate. Both species showed typical responses to anoxia (aspartate and glutamate catabolism, alanine and succinate accumulation) and D. laeve also showed this pattern during freezing, suggesting a natural switch to anaerobiosis to support freezing survival. PMID:17628806

  17. Competitive freezing in gold nanoparticles

    NASA Astrophysics Data System (ADS)

    Asuquo, Cletus C.; Bowles, Richard K.

    2013-05-01

    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.

  18. [Severe depression : psychoanalysis].

    PubMed

    Bouvet de la Maisonneuve, O

    2009-12-01

    The indication for psychoanalysis in severe depression is not clear. And yet, demands for this type of intervention are increasing, despite the absence of any form of consensus on the subject. Freud considered depression as a failure of analytical efforts and, based on this observation, revised his theory, in particular to include the notions of narcissism and the death drive. Many analysts have been reluctant to follow his teachings on this last point and provide depressed patients with analytical-type therapies aimed at restoring narcissism. Melanie Klein pushed Freud's ideas about depression even further and brought such therapies back to the heart of analytical practice. Jacques Lacan took the debate to another level by proposing an overhaul of the principles on which analysis has been based. Today, while following certain precautionary rules, true psychoanalyses can be proposed to patients with severe depression, whether of the bipolar, recurring or even neurotic type that can reach this level of severity. PMID:20141799

  19. Impact of Freezing Process on Salt Diffusivity of Seafood: Application to Salmon ( Salmo salar ) Using Conventional and Pressure Shift Freezing

    Microsoft Academic Search

    Ebrahim Alizadeh; Nicolas Chapleau; Marie de-Lamballerie; Alain Le-Bail

    2009-01-01

    The depression of the melting temperature of ice under pressure permits to obtain a rapid freezing of foods. The expected\\u000a benefit lies in reduced water diffusion from the intra- toward the extracellular media, resulting in a reduced drip loss during\\u000a thawing. Beside, the modification of the cellular structure induced by ice formation may affect the mass diffusivity of the\\u000a flesh.

  20. Performance Characteristics of an Isothermal Freeze Valve

    SciTech Connect

    Hailey, A.E.

    2001-08-22

    This document discusses performance characteristics of an isothermal freeze valve. A freeze valve has been specified for draining the DWPF melter at the end of its lifetime. Two freeze valve designs have been evaluated on the Small Cylindrical Melter-2 (SCM-2). In order to size the DWPF freeze valve, the basic principles governing freeze valve behavior need to be identified and understood.

  1. Freezing and thawing porous media: experimental study with a dielectric capacitive method

    NASA Astrophysics Data System (ADS)

    Fen-Chong, Teddy; Fabbri, Antonin

    2005-05-01

    A capacitive sensor-based apparatus has been used to study the ice/water phase change in consolidated porous media subjected to freezing and thawing. This technique relies on the dielectric properties of water, ice, air, and the mineral substrate in the radio-frequency range. It gives directly the freezing and thawing temperature depressions and indirectly provides an estimation of pore size distribution through the Gibbs-Thomson relation. It also holds good promise for evaluating the amount of liquid water in frozen porous media by combining drying and freezing tests. To cite this article: T. Fen-Chong, A. Fabbri, C. R. Mecanique 333 (2005).

  2. 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 ...

  3. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

  4. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

  5. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

  6. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

  7. 9 CFR 590.536 - Freezing operations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...Requirements § 590.536 Freezing operations. (a) Freezing rooms shall be kept clean...containers. (d) The outside of liquid egg containers shall be clean...by organoleptic examination after freezing to determine their...

  8. Freezing of living cells

    SciTech Connect

    Mazur, P.

    1985-01-01

    It can be calculated that a living cell will survive more than 5000 years at -196/sup 0/C. This ability to essentially stop biological time has important implications in medicine and agriculture, and in biological research. In medicine the chief implications are in the banking of transplantable tissues and organs and in in vitro fertilization. In agriculture the applications stem in part from the role of frozen embryos in amplifying the number of calves produced by high quanlity cows. The problem is how can cells survive both the cooling to such very low temperatures and the return to normal temperatures. The answers involve fundamental characteristics of cells such as the permeability of their surface membranes to water and solutes. These characteristics determine whether or not cells undergo lethal internal ice formation and other response during freezing and thawing. 27 refs., 12 figs.

  9. Adolescent Depression.

    ERIC Educational Resources Information Center

    Evans, Dina M.

    Affective disorder is characterized by maladaptive changes in mood, attitudes, energy level, and physical status. These changes constitute the basic dimensions of depression. Depression results from a combination of genetic and experiential factors. There are sex differences and age differences with regard to depression, and there is a high…

  10. Understanding Slag Freeze Linings

    NASA Astrophysics Data System (ADS)

    Fallah-Mehrjardi, Ata; Hayes, Peter C.; Jak, Evgueni

    2014-09-01

    Slag freeze linings, the formation of protective deposit layers on the inner walls of furnaces and reactors, are increasingly used in industrial pyrometallurgical processes to ensure that furnace integrity is maintained in these aggressive, high-temperature environments. Most previous studies of freeze-linings have analyzed the formation of slag deposits based solely on heat transfer considerations. These thermal models have assumed that the interface between the stationary frozen layer and the agitated molten bath at steady-state deposit thickness consists of the primary phase, which stays in contact with the bulk liquid at the liquidus temperature. Recent experimental studies, however, have clearly demonstrated that the temperature of the deposit/liquid bath interface can be lower than the liquidus temperature of the bulk liquid. A conceptual framework has been proposed to explain the observations and the factors influencing the microstructure and the temperature of the interface at steady-state conditions. The observations are consistent with a dynamic steady state that is a balance between (I) the rate of nucleation and growth of solids on detached crystals in a subliquidus layer as this fluid material moves toward the stagnant deposit interface and (II) the dissolution of these detached crystals as they are transported away from the interface by turbulent eddies. It is argued that the assumption that the interface temperature is the liquidus of the bulk material represents only a limiting condition, and that the interface temperature can be between T liquidus and T solidus depending on the process conditions and bath chemistry. These findings have implications for the modeling approach and boundary conditions required to accurately describe these systems. They also indicate the opportunity to integrate considerations of heat and mass flows with the selection of melt chemistries in the design of future high temperature industrial reactors.

  11. Psychosocial treatments for adolescent depression

    Microsoft Academic Search

    Peter M Lewinsohn; Gregory N Clarke

    1999-01-01

    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

  12. Nuclear freeze: myths and realities

    SciTech Connect

    Weinrod, W.B.

    1983-03-03

    A nuclear freeze would create serious problems for US strategic and political interests, and would not achieve the professed goal of a lower probability of nuclear war. It could increase strategic instability and reinforce the morally questionable Mutual Assured Destruction (MAD) approach of using civilian populations as hostages. Compliance would not be verifiable, and Soviet compliance would be doubtful. A review of the strategic and political implications and the basic assumptions of freeze advocates suggests that the movement has proved useful in forcing advocates of other positions to sharpen and refine their arguments. The challenge for freeze opponents is to make it clear to the public that the proposed freeze would benefit the Soviets and to offer viable alternatives for nuclear policy. 15 references.

  13. Exposing a dynamical signature of the freezing transition through the sound propagation gap

    NASA Astrophysics Data System (ADS)

    Martinez, V. A.; Zaccarelli, E.; Sanz, E.; Valeriani, C.; van Megen, W.

    2014-11-01

    The conventional view of freezing holds that nuclei of the crystal phase form in the metastable fluid through purely stochastic thermal density fluctuations. The possibility of a change in the character of the fluctuations as the freezing point is traversed is beyond the scope of this perspective. Here we show that this perspective may be incomplete by examination of the time autocorrelation function of the longitudinal current, computed by molecular dynamics for the hard-sphere fluid around its freezing point. In the spatial window where sound is overdamped, we identify a change in the long-time decay of the correlation function at the known freezing points of monodisperse and moderately polydisperse systems. The fact that these findings agree with previous experimental studies of colloidal systems in which particle are subject to diffusive dynamics, suggests that the dynamical signature we identify with the freezing transition is a consequence of packing effects alone.

  14. Freeze concentration of fruit juices.

    PubMed

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

    1984-01-01

    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

  15. A study of the freezing of water in human uterine muscle by proton magnetic resonance.

    PubMed

    Adamski, J; Olszewski, K J; Bu?ko, J; Pi?lewski, N

    1985-01-01

    Human uterine muscle and its nuclear fractions have been studied by means of nuclear magnetic resonance at temperatures from 300 degrees K to 143 degrees K. Different proton populations have been detected above and below the freezing point. On this basis it is suggested that the freezing of water in uterine muscle starts at the cell nuclei. PMID:4033376

  16. Hepatitis B vaccine freezing in the Indonesian cold chain: evidence and solutions.

    PubMed Central

    Nelson, Carib M.; Wibisono, Hariadi; Purwanto, Hary; Mansyur, Isa; Moniaga, Vanda; Widjaya, Anton

    2004-01-01

    OBJECTIVES: To document and characterize freezing temperatures in the Indonesian vaccine cold chain and to evaluate the feasibility of changes designed to reduce the occurrence of freezing. METHODS: Data loggers were used to measure temperatures of shipments of hepatitis B vaccine from manufacturer to point of use. Baseline conditions and three intervention phases were monitored. During each of the intervention phases, vaccines were removed progressively from the standard 2-8 degrees C cold chain. FINDINGS: Freezing temperatures were recorded in 75% of baseline shipments. The highest rates of freezing occurred during transport from province to district, storage in district-level ice-lined refrigerators, and storage in refrigerators in health centres. Interventions reduced freezing, without excessive heat exposure. CONCLUSIONS: Inadvertent freezing of freeze-sensitive vaccines is widespread in Indonesia. Simple strategies exist to reduce freezing - for example, selective transport and storage of vaccines at ambient temperatures. The use of vaccine vial monitors reduces the risk associated with heat-damaged vaccines in these scenarios. Policy changes that allow limited storage of freeze-sensitive vaccines at temperatures >2-8 degrees C would enable flexible vaccine distribution strategies that could reduce vaccine freezing, reduce costs, and increase capacity. PMID:15042231

  17. Depression among Asian Americans: Review and Recommendations

    PubMed Central

    Kalibatseva, Zornitsa; Leong, Frederick T. L.

    2011-01-01

    This article presents a review of the prevalence and manifestation of depression among Asian Americans and discusses some of the existing issues in the assessment and diagnosis of depression among Asian Americans. The authors point out the diversity and increasing numbers of Asian Americans and the need to provide better mental health services for this population. While the prevalence of depression among Asian Americans is lower than that among other ethnic/racial groups, Asian Americans receive treatment for depression less often and its quality is less adequate. In addition, the previous belief that Asians somatize depression may become obsolete as more evidence appears to support that Westerners may “psychologize” depression. The cultural validity of the current DSM-IV conceptualization of depression is questioned. In the course of the review, the theme of complexity emerges: the heterogeneity of ethnic Asian American groups, the multidimensionality of depression, and the intersectionality of multiple factors among depressed Asian Americans. PMID:21961060

  18. ANNAGNPS: ACCOUNTING FOR SNOWPACK, SNOWMELT, FREEZING AND THAWING OF SOIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The watershed model, AnnAGNPS (Annualized AGricultural Non-Point Source Pollution model) has been enhanced by incorporating winter climate algorithms that account for frozen soil conditions. The model includes snowpack accumulation and melt, and the freeze/thaw process in the soil. Three major imp...

  19. Ultrasonic Measurements of Unconsolidated Saline Sediments During Freeze/Thaw Cycles: The Seismic Properties of Cryopeg Environments

    NASA Astrophysics Data System (ADS)

    Dou, S.; Ajo Franklin, J. B.

    2013-12-01

    Saline permafrost and cryopegs (hypersaline unfrozen layers/zones within permafrost) are widespread in the Arctic coastal area as a result of marine transgression and regression in recent geological history. Owing to the freezing-point depression effect of soluble salts, they contain more unfrozen water than non-saline frozen sediments when subjected to the same permafrost temperatures (e.g., from 0 to -15 °C). Mapping subsurface cryopeg structure remains a challenging geophysical task due to the poor penetration of GPR in highly conductive fluids and related limitations for lower frequency EM techniques. Seismic profiling, particularly surface wave characterization, provides one possible approach to delineate the extent of cryopeg bodies. However, interpretation of such surveys is currently limited by the sparse database of measurements examining the seismic properties of unconsolidated materials saturated with saline fluids at sub-zero temperatures. We present the results of experiments examining seismic velocity in the ultrasonic range for both synthetic and natural permafrost sediments during freeze/thaw cycles; in these experiments, use of a range of brine salinities allows us to evaluate the properties of cryopeg sediments at in-situ conditions, a prerequisite for quantitative interpretation of seismic imaging results. Because of the abundant unfrozen water and less developed inter-granular ice structure, the seismic properties of saline permafrost typically falls between frozen and unfrozen soils. We conducted ultrasonic measurements of a freeze-thaw cycle on 20-30 Ottawa sand (grain size 590-840 ?m) as well as natural mineral soils from the Barrow Environmental Observatory (BEO) saturated with brines of different salinities (0-2.5 M NaCl). For each salinity, seismic properties were measured using the ultrasonic (~1 MHz) pulse-transmission method in the temperature range from 20 to -30 °C. Similar to sediments saturated with low salinity fluids, seismic velocities increase significantly upon freezing in brine-saturated samples due to the formation of ice. However, substantial differences were observed: First, the onset of the velocity increase occurred at temperatures significantly below 0 °C (e.g., as low as -11.8 °C for 2.5 M pore-water salinity); Second, instead of having a stepwise velocity increase (temperature derivative of velocity on the order of 1000 m/s/°C) in the immediate neighborhood of the freezing-point as in non-saline samples, velocities in saline samples exhibit a gradual increase (dv/dT as low as ~70 m/s/°C) in temperatures between the freezing-point and the eutectic-point (~-25 °C) of NaCl solutions. Unusual increases in attenuation were also observed in the vicinity of freezing. Our results indicate that saline permafrost and cryopegs have distinct seismic properties when compared with their non-saline counterparts under the same thermal conditions. Moreover, the very low seismic velocities observed in this laboratory study are consistent with the low-velocity zones at Barrow, Alaska that were previously found through field-scale geophysical investigations.

  20. 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 ...

  1. Depression and Parkinson's Disease

    MedlinePLUS

    ... difficult, so proper treatment is important. What is depression? Major depressive disorder, or depression, is a serious ... older have depression. 1 Signs and Symptoms of Depression Ongoing sad, anxious, or empty feelings Feeling hopeless ...

  2. Depression and Diabetes

    MedlinePLUS

    ... difficult, so proper treatment is important. What is depression? Major depressive disorder, or depression, is a serious ... older have depression. 1 Signs and Symptoms of Depression Ongoing sad, anxious, or empty feelings Feeling hopeless ...

  3. Depression and Cancer

    MedlinePLUS

    ... difficult, so proper treatment is important. What is depression? Major depressive disorder, or depression, is a serious ... older have depression. 1 Signs and Symptoms of Depression Ongoing sad, anxious, or empty feelings Feeling hopeless ...

  4. Freeze-in through portals

    NASA Astrophysics Data System (ADS)

    Blennow, Mattias; Fernandez-Martínez, Enrique; Zaldívar, Bryan

    2014-01-01

    The popular freeze-out paradigm for Dark Matter (DM) production, relies on DM-baryon couplings of the order of the weak interactions. However, different search strategies for DM have failed to provide a conclusive evidence of such (non-gravitational) interactions, while greatly reducing the parameter space of many representative models. This motivates the study of alternative mechanisms for DM genesis. In the freeze-in framework, the DM is slowly populated from the thermal bath while never reaching equilibrium. In this work, we analyse in detail the possibility of producing a frozen-in DM via a mediator particle which acts as a portal. We give analytical estimates of different freeze-in regimes and support them with full numerical analyses, taking into account the proper distribution functions of bath particles. Finally, we constrain the parameter space of generic models by requiring agreement with DM relic abundance observations.

  5. Freezing of a Liquid Marble

    E-print Network

    Ali Hashmi; Adam Strauss; Jie Xu

    2012-07-03

    In this study, we present for the first time the observations of a freezing liquid marble. In the experiment, liquid marbles are gently placed on the cold side of a Thermo-Electric Cooler (TEC) and the morphological changes are recorded and characterized thereafter. These liquid marbles are noticed to undergo a shape transition from a spherical to a flying-saucer shaped morphology. The freezing dynamics of liquid marbles is observed to be very different from that of a freezing water droplet on a superhydrophobic surface. For example, the pointy tip appearing on a frozen water drop could not be observed for a frozen liquid marble. In the end, we highlight a possible explanation for the observed morphology.

  6. Depression (lesson)

    NSDL National Science Digital Library

    2009-04-14

    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.

  7. Postpartum Depression

    MedlinePLUS

    ... How is postpartum depression different from the “baby blues”? The “baby blues” is a term used to describe the feelings ... about, or tired from, providing that care. Baby blues, which affects up to 80 percent of mothers, ...

  8. Postpartum Depression

    MedlinePLUS

    ... many people may realize. It's important for new mothers — and those who love them — to understand the ... for help. With the proper support and treatment, mothers who are experiencing any degree of postpartum depression ...

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

    NASA Technical Reports Server (NTRS)

    Cutbirth, J. Michael

    2012-01-01

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

  10. Thermal analysis on the realization of the tin fixed point

    NASA Astrophysics Data System (ADS)

    Tsai, S. F.

    2013-09-01

    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).

  11. Measurement of the size of intracellular ice crystals in mouse oocytes using a melting point depression method and the influence of intracellular solute concentrations

    Microsoft Academic Search

    Xu Han; John K. Critser

    2009-01-01

    Characterization of intracellular ice formed during the cooling procedures of cells significantly benefits the development and optimization design of cryopreservation or cryosurgery techniques. In this study, we investigated the influence of the concentration of extracellular non-permeable and permeable solutes on the melting points of the intracellular ice in mouse oocytes using cryomicroscopy. The results showed that the melting points of

  12. Central GABAergic Systems and Depressive Illness

    Microsoft Academic Search

    G. Tunnicliff; E. Malatynska

    2003-01-01

    Clinical depression and other mood disorders are relatively common mental illnesses but therapy for a substantial number of patients is unsatisfactory. For many years clinicians and neuroscientists believed that the evidence pointed toward alterations in brain monoamine function as the underlying cause of depression. This point of view is still valid. Indeed, much of current drug therapy appears to be

  13. Entropy Budgets in Oscillating and Freezing Systems

    NASA Astrophysics Data System (ADS)

    Lorenz, R. D.

    2005-12-01

    An interesting spontaneously oscillating system was demonstrated some decades ago by Welander : an open-topped water tank supplied with a continuous supply of heat is exposed to chilled air. A layer of ice forms, as one might expect. However, the ice retards the loss of heat to the air, and the water temperature rises until eventually the ice melts. The enhanced heat loss allows the system to cool again to the point where ice can form, and the cycle repeats. The oscillating behaviour is counterintuitive (like another freezing phenomenon, the Mpemba effect, wherein a warm liquid will begin freezing before a cool one), but is in full accord with the laws of thermodynamics and can be demonstrated in the laboratory and with numerical models. Oscillations occur in specific regions of parameter space (heating rate, heat transfer coefficients etc) - smooth variation, e.g. of the ice:air heat transfer coefficient yields a smooth variation of entropy production, except for a jump to increased entropy production when oscillations begin. A geophysical system where similar oscillations may occur is the icy Jovian satellite Europa, which appears to have a young crust. More generally, where a system is subject to a varying excitation (such as diurnal or seasonal forcing of the climate of Earth or Mars) the presence of phase changes such as melting of water or the condensation of carbon dioxide as frost have an important impact on the entropy budget of the system.

  14. Freeze-drying today and tomorrow.

    PubMed

    Leary, J H; Stanford, E A

    1976-10-01

    The freeze-drying process and equipment have been improved over the years; the cycle times have shortened and the dried products have improved as a result. This talk will deal with these improvements and how we have progressed from the early systems to where we are today. Such areas of discussion will include: vacuum pumping systems, how they are sized and designed to meet the needs for general and special applications; heat transfer systems, and their use in maintaining the drying profile; condensing surface design, and what is best for certain types of dryers; controls and instrumentation, and how these have played a big part in the drying process and have made it possible to get repeatability; refrigeration systems, and the part they play in the performance of freeze-drying; and lastly the effect of internal stoppering, bottomless trays, and other items such as these have had on the present state of the art. It goes without saying that there have been many changes and there will continue to be changes and we shall endeavor to look into the future--as to what might well bo some of these changes. Included in the talk will be a number of slides and illustrations to point out the various items as they are discussed. PMID:1030422

  15. Nachweis von Feature Freezes durch Clustering Nachweis von Feature Freezes durch Clustering

    E-print Network

    Grabowski, Jens

    Nachweis von Feature Freezes durch Clustering Nachweis von Feature Freezes durch Clustering Steen von Feature Freezes durch Clustering (1/21) #12;Nachweis von Feature Freezes durch Clustering �berblick Einführung Grundlagen Metriken Maschinelles Lernen Sammeln von Metrikdaten Anwendung des k

  16. Strategies for exploration of freeze responsive gene expression: advances in vertebrate freeze toleranceq

    Microsoft Academic Search

    Kenneth B. Storey

    Winter survival for many cold-blooded species involves freeze tolerance, the capacity to endure the freezing of a high percentage of total body water as extracellular ice. The wood frog (Rana sylvatica) is the primary model animal used for studies of vertebrate freeze tolerance and current studies in my lab are focused on the freeze-induced changes in gene expression that support

  17. Freeze\\/thaw power system. [water expansion

    Microsoft Academic Search

    1978-01-01

    A freeze-thaw power cycle is described that includes a piston driven by the expansion power of a fluid such as water in a cyclinder on freezing and the thawing thereof with alternate, rapid freezing and thawing of the fluid by low and high temperature means with heat transfer rates facilitated by the use of heat pipes or tubes or other

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

    Microsoft Academic Search

    Lewis L Judd; Hagop S Akiskal; Martin P Paulus

    1997-01-01

    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

  19. Inbreeding depression and heterosis : Expected means and variances among inbred lines

    E-print Network

    Paris-Sud XI, Université de

    Inbreeding depression and heterosis : Expected means and variances among inbred lines depression are investigated from a theoretical point of view in an experiment involving several inbred lines depression phenomena ! Many experiments led to the definition of the relations hipbetweentheincrease

  20. Improvement of Freezing Quality of Food by Pre-dehydration with Microwave-Vacuum Drying

    NASA Astrophysics Data System (ADS)

    Hamidi, Nurkholis; Tsuruta, Takaharu

    Partial dehydration by microwave vacuum drying has been applied to tuna, oyster and mackerel prior to freezing in order to reduce quality damages due to freezing and thawing. Samples were dehydrated at pressure of 4kPa and temperature lower than 25°C. Two cooling conditions were tested in the experiment by using the freezing chamber of temperatures -20°C and -80°C. The experimental results showed that decreasing the water content in tuna could lower the freezing point temperature and made the freezing time shorter. It was also found that removing some water was effective to reduce the size of ice crystal and the drip loss in mackerel. After thawing, the pre-dehydrated mackerel showed better microstructure than that frozen without pre-treatment. Furthermore, the sensory tests have been done by a group of panelist for the evaluation on aroma, flavor, and general acceptability of mackerels.

  1. Heat pump with freeze-up prevention

    DOEpatents

    Ecker, Amir L. (Dallas, TX)

    1981-01-01

    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.

  2. Freeze Technology for Nuclear Applications - 13590

    SciTech Connect

    Rostmark, Susanne C.; Knutsson, Sven [Lulea University of Technology (Sweden)] [Lulea University of Technology (Sweden); Lindberg, Maria [Studsvik Nuclear AB, 611 82 Nykoeping (Sweden)] [Studsvik Nuclear AB, 611 82 Nykoeping (Sweden)

    2013-07-01

    Freezing of soil materials is a complicated process of a number of physical processes: - freezing of pore water in a thermal gradient, - cryogenic suction causing water migration and - ice formation expanding pores inducing frost heave. Structural changes due to increase of effective stress during freezing also take place. The over consolidation gives a powerful dewatering/drying effect and the freeze process causes separation of contaminates. Artificial ground freezing (AGF is a well established technique first practiced in south Wales, as early as 1862. AGF is mostly used to stabilize tunnels and excavations. During the last ten years underwater applications of freeze technologies based on the AGF have been explored in Sweden. The technology can, and has been, used in many different steps in a remediation action. Freeze Sampling where undisturbed samples are removed in both soft and hard sediment/sludge, Freeze Dredging; retrieval of sediment with good precision and minimal redistribution, and Freeze Drying; volume reduction of contaminated sludge/sediment. The application of these technologies in a nuclear or radioactive environment provides several advantages. Sampling by freezing gives for example an advantage of an undisturbed sample taken at a specified depth, salvaging objects by freezing or removal of sludges is other applications of this, for the nuclear industry, novel technology. (authors)

  3. Diagnosing depression

    PubMed Central

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

    2005-01-01

    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. PMID:16926948

  4. Freeze chromatography method and apparatus

    DOEpatents

    Scott, C.D.

    1987-04-16

    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.

  5. Depression and Pregnancy

    MedlinePLUS

    Depression and Pregnancy This sheet talks about the risks of depression during pregnancy. With each pregnancy, all women have a 3% ... is depression and how common is it in pregnancy? Depression is a serious medical illness that has ...

  6. Depression in Older Adults

    MedlinePLUS

    ... You are here Home » Depression In Older Adults Depression In Older Adults Depression affects more than 19 ... combination of both. [8] Older Adult Attitudes Toward Depression: According to a Mental Health America survey [9] ...

  7. Depression and Smoking

    MedlinePLUS

    ... Tools » Depression Basics » Depression and Smoking Depression and Smoking Why is depression more common in smokers? Nobody ... towards a healthier, new lifestyle. Start Today Quitting Smoking Happens one craving at a time. one monday ...

  8. Optimal Freeze Cycle Length for Renal Cryotherapy

    PubMed Central

    Young, Jennifer Lee; Khanifar, Elham; Narula, Navneet; Ortiz-Vanderdys, Cervando Gerardo; Kolla, Surendra Babu; Pick, Donald Lowell; Sountoulides, Petros George; Kaufmann, Oskar Grau; Osann, Kathryn Elizabeth; Huynh, Victor Buu; Kaplan, Adam Geoffrey; Andrade, Lorena Aurora; Louie, Michael Ken; McDougall, Elspeth Marguerita; Clayman, Ralph Victor

    2014-01-01

    Purpose To our knowledge the optimal freeze cycle length in renal cryotherapy is unknown. Ten-minute time based freeze cycles were compared to temperature based freeze cycles to ?20C. Materials and Methods Laparoscopic renal cryotherapy was performed on 16 swine. Time based trials consisted of a double 10-minute freeze separated by a 5-minute thaw. Temperature based trials were double cycles of 1, 5 or 10-minute freeze initiated after 1 of 4 sensors indicated ?20C. A 5-minute active thaw was used between freeze cycles. Control trials consisted of cryoneedle placement for 25 minutes without freeze or thaw. Viability staining and histological analysis were done. Results There was no difference in cellular necrosis between any of the temperature based freeze cycles (p = 0.1). Time based freeze cycles showed more nuclear pyknosis, indicative of necrosis, than the 3 experimental freeze cycles for the renal cortex (p = 0.05) but not for the renal medulla (p = 0.61). Mean time to ?20C for freeze cycle 1 was 19 minutes 10 seconds (range 9 to 46 minutes). In 4 of 21 trials (19%) ?20C was never attained despite freezing for 25 to 63 minutes. Conclusions There was no difference in immediate cellular necrosis among double 1, 5 or 10-minute freeze cycles. Cellular necrosis was evident on histological analysis for trials in which ?20C was attained and in freeze cycles based on time alone. With a standard 10-minute cryoablation period most treated parenchyma 1 cm from the probe never attained ?20C. Cell death appeared to occur at temperatures warmer than ?20C during renal cryotherapy. PMID:21600606

  9. Depression (PDQ)

    MedlinePLUS

    ... alcoholism or drug abuse . A personal history of mental problems. A weak social support system (not being married, having few family members or friends, having a job where you work alone). Stress caused by life events other than the cancer. Health problems that are known to cause depression (such ...

  10. Postpartum Depression

    MedlinePLUS

    What are the postpartum blues? About 2–3 days after childbirth, some women begin to feel depressed, anxious, and upset. They may feel angry with ... a baby These feelings, often called the postpartum blues , may come and go in the first few ...

  11. Contact freezing: a review of experimental studies

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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.

  12. Ultrafast microfluidic mixer and freeze-quenching device.

    PubMed

    Lin, Yu; Gerfen, Gary J; Rousseau, Denis L; Yeh, Syun-Ru

    2003-10-15

    The freeze-quenching technique is extremely useful for trapping meta-stable intermediates populated during fast chemical or biochemical reactions. The application of this technique, however, is limited by the long mixing time of conventional solution mixers and the slow freezing time of cryogenic fluids. To overcome these problems, we have designed and tested a novel microfluidic silicon mixer equipped with a new freeze-quenching device, with which reactions can be followed down to 50 micros. In the microfluidic silicon mixer, seven 10-microm-diameter vertical pillars are arranged perpendicular to the flow direction and in a staggered fashion in the 450-pL mixing chamber to enhance turbulent mixing. The mixed-solution jet, with a cross section of 10 microm x 100 microm, exits from the microfluidic silicon mixer with a linear flow velocity of 20 m/s. It instantaneously freezes on one of two rotating copper wheels maintained at 77 K and is subsequently ground into an ultrafine powder. The ultrafine frozen powder exhibits excellent spectral quality and high packing factor and can be readily transferred between spectroscopic observation cells. The microfluidic mixer was tested by the reaction between azide and myoglobin at pH 5.0. It was found that complete mixing was achieved within the mixing dead time of the mixer (20 micros), and the first observable point for this coupled device was determined to be 50 micros, which is approximately 2 orders of magnitude faster than commercially available instruments. PMID:14710815

  13. Measurement of the size of intracellular ice crystals in mouse oocytes using a melting point depression method and the influence of intracellular solute concentrations

    PubMed Central

    Han, Xu; Critser, John K.

    2009-01-01

    Characterization of intracellular ice formed during the cooling procedures of cells significantly benefits the development and optimization design of cryopreservation or cryosurgery techniques. In this study, we investigated the influence of the concentration of extracellular non-permeable and permeable solutes on the melting points of the intracellular ice in mouse oocytes using cryomicroscopy. The results showed that the melting points of the intracellular ice are always lower than the extracellular ice. Based on this observation and the Gibbs-Thomson relation, we established a physical model to calculate the size of intracellular ice crystals and described its relationship with the concentrations of intracellular permeating solutes and macromolecules. This model predicts that the increased concentration of macromolecules in cells, by increasing the extracellular non-permeating solute concentration, can significantly lower the required concentration of permeable solutes for intracellular vitrification. The prediction was tested through the cryomicroscopic observation of the co-existence of intracellular vitrification and extracellular crystallization during cooling at 100°C/min when the extracellular solutions contain 5 molal (m) ethylene glycol and 0.3 to 0.6 m NaCl. PMID:19729005

  14. Transverse freezing of thin liquid films

    NASA Astrophysics Data System (ADS)

    Beerman, Michael

    A pair of coupled non-linear partial differential equations is derived using lubrication theory that govern the morphology of a thin, liquid film of a pure and a binary metal alloy, bounded by the liquid's solid phase and a passive gas phase. The analysis is motivated by the directional freezing of metallic foams, and is a first attempt to model transverse freezing in thin films that form in foam networks, but also applies to thin film layers in general. Both the no-slip crystal-melt and the free melt-gas interfaces are deformable. The governing pair of non-linear differential equations for the most general case incorporate crystal-melt and melt-gas surface tension, latent heat, heat transfer, volume change, molecular interactions, thermocapillary and dilute phase concentration effects. Linear analysis of a uniform film reveals a variety of instabilities. A unique wavenumber is selected at the onset of instability in the case of an applied temperature gradient with vanishing crystal-melt surface tension. This system reproduces the isothermal result for a rigid solid-liquid interface in which a band of wavenumbers is unstable. A new long-wave instability has been identified, for the case with CM surface tension, that is due to the coupling of the interfaces. Numerical solutions of the fully non-linear system provide film evolution and rupture times, and show that, near the critical conditions, rupture can occur by the growth of standing or traveling waves. The numerics also reveals complex non-linear interactions between unstable modes. It is found that for most unstable initial conditions, the crystal-melt interface retreats by melting away from the tip region of the encroaching melt-gas interface due to a rise in heat flux as the film thins near the rupture point.

  15. The response of Anisakis larvae to freezing.

    PubMed

    Wharton, D A; Aalders, O

    2002-12-01

    Anisakis third stage larvae utilize a variety of fish as intermediate hosts. Uncooked fish are rendered safe for human consumption by freezing. Larvae freeze by inoculative freezing from the surrounding medium but can survive freezing at temperatures down to -10 degrees C. This ability may be aided by the production of trehalose, which can act as a cryoprotectant, but does not involve recrystallization inhibition. Monitoring of fish freezing in commercial blast freezers and under conditions which simulate those of a domestic freezer, indicate that it can take a long time for all parts of the fish to reach a temperature that will kill the larvae. This, and the moderate freezing tolerance of larvae, emphasizes the need for fish to be frozen at a low enough temperature and for a sufficient time to ensure that fish are safe for consumption. PMID:12498643

  16. Rotary replication for freeze-etching

    Microsoft Academic Search

    LUKAS H. MARGARITIS; ARNLJOT ELGSAETER; DANIEL BRANTON

    1977-01-01

    Rotary replication has been adapted to freeze-etching and evaluated using T4 polyheads, erythrocyte ghosts, and chloroplast membranes. Conventional elec- tron 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. Freeze-etching has exposed

  17. Reptile freeze tolerance: metabolism and gene expression.

    PubMed

    Storey, Kenneth B

    2006-02-01

    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

  18. Nonpsychotic Postpartum Depression Among Adolescent Mothers

    Microsoft Academic Search

    Beth R. Troutman; Carolyn E. Cutrona

    1990-01-01

    This study examined the extent to which childbearing increases vulnerability to clinical depression and depressive symptomatology among primiparous adolescent girls (ages 14 to 18). Childbearing Ss (n = 128) were assessed during pregnancy, 6 weeks postpartum, and 1 year postpartum. Matched nonchildbearing Ss (n = 114) were assessed at corresponding time points. Six weeks postpartum, 6% of the childbearing adolescents

  19. Influence of chemical and freezing fixation methods in the freeze-fracture of stratum corneum

    Microsoft Academic Search

    O López; C López-Iglesias; M Cócera; P Walther; J. L Parra; A de la Maza

    2004-01-01

    A comparison between two fixation techniques for freeze-fracture was established. Stratum corneum (SC) samples from pig epidermis were fixed using high-pressure freezing (HPF) and using plunging in propane freezing; the latter after chemical fixation. Then, frozen samples were freeze-fractured, coated with platinum–carbon, and visualized using a high-resolution low-temperature scanning electron microscope and a transmission electron microscope. Our results indicate that

  20. Strategies for exploration of freeze responsive gene expression: advances in vertebrate freeze toleranceq

    E-print Network

    Storey, Kenneth B.

    of the prominent features of wood frog freeze tolerance is the production of huge amounts of glucose 2003 Abstract Winter survival for many cold-blooded species involves freeze tolerance, the capacity sylvatica) is the primary model animal used for studies of vertebrate freeze tolerance and current studies

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

    NASA Technical Reports Server (NTRS)

    Karel, M.; Flink, J. M.

    1976-01-01

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

  2. Depression: What We Know.

    ERIC Educational Resources Information Center

    Lobel, Brana; Hirschfeld, Robert M. A.

    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 second…

  3. Survey of depression by Beck Depression Inventory in uremic patients undergoing hemodialysis and hemodiafiltration.

    PubMed

    Su, Shu-Fen; Ng, Hwee-Yeong; Huang, Tiao-Lai; Chi, Po-Jui; Lee, Yueh-Ting; Lai, Chun-Ren; Lin, Yau-Hsing; Huang, Pei-Chen; Lee, Chien-Te

    2012-12-01

    High prevalence of depression has been reported in patients with end stage kidney disease and depression is associated with increased morbidity and mortality. We aimed to investigate the prevalence of depression in patients receiving standard hemodialysis (SHD) and hemodiafiltration (HDF) and compare the associated factors between these treatment modalities. The Beck Depression Inventory (BDI) was used to survey for major depressive symptoms. Demographic and biochemical data were reviewed and collected. Point prevalence of depression in HDF patients was significantly lower than SHD patients (23.9% vs. 43.1%, P < 0.05). The BDI score was also higher in SHD than HDF group (13.2 ± 11.6 vs. 8.7 ± 11.2, P < 0.05). SHD patients with major depressive symptoms had significantly lower levels of hemoglobin, albumin, creatinine, sodium and hand grip strength but had higher prevalence of diabetes and high sensitivity C-reactive protein (hs-CRP) levels. In HDF patients, phosphorus level was significantly lower in patients with major depressive symptoms. Logistic regression analysis revealed that hs-CRP, serum sodium and hand grip strength were significantly associated with major depressive symptoms in patients treated with SHD; while serum phosphorus was identified in HDF groups. We concluded that prevalence of depression was high in dialysis patients. Patients receiving HDF had a lower mean BDI score and a nearly 50% lower prevalence rate of major depressive symptoms than that of SHD. Factors associated with depression were different between two modalities. PMID:23190518

  4. Nutritional Interventions in Depression and Perinatal Depression

    PubMed Central

    Rechenberg, Kaitlyn; Humphries, Debbie

    2013-01-01

    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. PMID:23766734

  5. Shyness Predicts Depressive Symptoms among Adolescents : A Prospective Study

    ERIC Educational Resources Information Center

    Murberg, Terje A.

    2009-01-01

    This study examines the relation between shyness, social support and depressive symptoms in a sample of 259 students (aged 14-16 years) in two secondary schools. Results at both time-points showed positive associations of depressive symptoms with shyness and with being female and negative associations of depressive symptoms with social support and…

  6. Metabolic Activity of Permafrost Bacteria below the Freezing Point

    PubMed Central

    Rivkina, E. M.; Friedmann, E. I.; McKay, C. P.; Gilichinsky, D. A.

    2000-01-01

    Metabolic activity was measured in the laboratory at temperatures between 5 and ?20°C on the basis of incorporation of 14C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5°C) to 20 days (?10°C) to ca. 160 days (?20°C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature. PMID:10919774

  7. Metabolic activity of permafrost bacteria below the freezing point

    NASA Technical Reports Server (NTRS)

    Rivkina, E. M.; Friedmann, E. I.; McKay, C. P.; Gilichinsky, D. A.

    2000-01-01

    Metabolic activity was measured in the laboratory at temperatures between 5 and -20 degrees C on the basis of incorporation of (14)C-labeled acetate into lipids by samples of a natural population of bacteria from Siberian permafrost (permanently frozen soil). Incorporation followed a sigmoidal pattern similar to growth curves. At all temperatures, the log phase was followed, within 200 to 350 days, by a stationary phase, which was monitored until the 550th day of activity. The minimum doubling times ranged from 1 day (5 degrees C) to 20 days (-10 degrees C) to ca. 160 days (-20 degrees C). The curves reached the stationary phase at different levels, depending on the incubation temperature. We suggest that the stationary phase, which is generally considered to be reached when the availability of nutrients becomes limiting, was brought on under our conditions by the formation of diffusion barriers in the thin layers of unfrozen water known to be present in permafrost soils, the thickness of which depends on temperature.

  8. 7 CFR 58.620 - Freezing and packaging rooms.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Freezing and packaging rooms. 58.620 Section... Rooms and Compartments § 58.620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  9. 7 CFR 58.620 - Freezing and packaging rooms.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Freezing and packaging rooms. 58.620 Section... Rooms and Compartments § 58.620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  10. 7 CFR 58.620 - Freezing and packaging rooms.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Freezing and packaging rooms. 58.620 Section... Rooms and Compartments § 58.620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  11. 7 CFR 58.620 - Freezing and packaging rooms.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Freezing and packaging rooms. 58.620 Section... Rooms and Compartments § 58.620 Freezing and packaging rooms. The rooms used for freezing and packaging frozen desserts shall be...

  12. 7 CFR 305.7 - Quick freeze treatment requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Quick freeze treatment requirements. 305.7 Section 305.7...DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS § 305.7 Quick freeze treatment requirements. Quick freeze...

  13. 7 CFR 305.7 - Quick freeze treatment requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Quick freeze treatment requirements. 305.7 Section 305.7...DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS § 305.7 Quick freeze treatment requirements. Quick freeze...

  14. 7 CFR 305.18 - Quick freeze treatment schedule.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Quick freeze treatment schedule. 305.18 Section 305.18 Agriculture...SERVICE, DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS Quick Freeze Treatments § 305.18 Quick freeze treatment...

  15. 7 CFR 305.7 - Quick freeze treatment requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Quick freeze treatment requirements. 305.7 Section 305.7...DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS § 305.7 Quick freeze treatment requirements. Quick freeze...

  16. 7 CFR 305.7 - Quick freeze treatment requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Quick freeze treatment requirements. 305.7 Section 305.7...DEPARTMENT OF AGRICULTURE PHYTOSANITARY TREATMENTS § 305.7 Quick freeze treatment requirements. Quick freeze...

  17. Depression and Osteoporosis

    MedlinePLUS

    ... see the NIMH booklet on Depression . What is osteoporosis? Osteoporosis is a disease that thins and weakens ... due to osteoporosis. 3 How are depression and osteoporosis linked? Studies show that older people with depression ...

  18. Depression and Suicide Risk

    MedlinePLUS

    ... as if life isn’t worth living. i Depression and Suicide Risk (2014) Prevalence: Ranges of lifetime ... disorder due to another medical disorder Relationship Between Depression & Suicide: Depression is the psychiatric diagnosis most 1. ...

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

    NASA Astrophysics Data System (ADS)

    Pearce, J. V.

    2013-09-01

    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.

  20. Freeze-drying for morphological control of high performance semi-interpenetrating polymer networks. III

    NASA Technical Reports Server (NTRS)

    Hsiung, H. J.; Hansen, M. G.; Pater, R. H.

    1991-01-01

    The feasibility of using a freeze-drying (solvent removal by sublimation) approach for controlling the morphology of a high-performance semi-IPN is assessed. A high-performance thermoplastic polyimide and commercially available 4,4'-bismaleimide diphenylenemethane were dissolved in a solvent, 1,3,5-trioxane. The solvent was removed from the constituents by freeze-drying. For purposes of comparison, the constituents were dissolved in a high-boiling-point solvent, N,N-dimethylformamide. The solvent was removed from the solution by evaporation. The physical and mechanical properties and phase morphology of the neat resins and composites prepared by freeze-drying and traditional solution methods are presented and compared. It is concluded that the TG is higher and that the magnitude of minor constituent separation is less in the freeze-dry processed materials than for the processed solution.

  1. Depression, confidence, and decision Running head: DEPRESSION, CONFIDENCE, AND DECISION

    E-print Network

    Koutstaal, Wilma

    Depression, confidence, and decision -1- Running head: DEPRESSION, CONFIDENCE, AND DECISION Depression, confidence, and decision: Evidence against depressive realism Tiffany Fu, 1 Wilma Koutstaal, 1, 2;Depression, confidence, and decision -2- Abstract This research examined how retrospective self

  2. A Phase-Field Solidification Model of Almost Pure ITS-90 Fixed Points

    NASA Astrophysics Data System (ADS)

    Large, M. J.; Pearce, J. V.

    2014-07-01

    A two-dimensional axisymmetric phase-field model of thermo-solutal solidification in freezing-point cells used for calibrating standard platinum resistance thermometers for realization and dissemination of the International Temperature Scale of 1990 is presented. The cell is essentially a graphite crucible containing an ingot of very pure metal (of order 99.9999 %). A graphite tube is inserted along the axis of the ingot to enable immersion of the thermometer in the metal. In this study, the metal is tin (freezing temperature of ). During the freezing of these cells, a steady, reproducible temperature is realized, with a defined temperature that can be used to calibrate thermometers with uncertainties mK. The model is applied to understand the effect of experimental parameters, such as initiation technique and furnace homogeneity, on the measured freezing curve. Results show that freezing curves whose behavior is consistent with the Scheil theory of solidification can be obtained with a specific furnace temperature profile, and provided that the freeze is of a long duration, the results are consistent with previous one-dimensional models and experiments. Morphological instability is observed with the inner interface initiation technique, causing the interface to adopt a cellular structure. This elevates the measured temperature, in accordance with the Gibbs-Thomson effect. In addition, the influence of initiation techniques on the solidification behavior is examined. The model indicates that an initially smooth inner mantle can `de-wet' from the thermometer well-forming agglomerated solid droplets, following recalescence, under certain conditions. This manifests as a measured temperature depression due to the Gibbs-Thomson effect, with a magnitude of to in simulations. The temperature rises to that of the stable outer mantle as freezing progresses and the droplets re-melt. It is demonstrated that the effect occurs below a critical mantle thickness. A physical explanation for the origin of the effect is offered showing that it is consistent with solid-state de-wetting phenomena. Consideration is also given to the limitations of the current model configuration.

  3. [Prevalence of major depression in primary care practices in Hungary].

    PubMed

    Péter, Torzsa; Zoltán, Rihmer; Xénia, Gonda; Bea, Sebestyen; Nora, Szokontor; Laszlo, Kalabay

    2008-12-01

    Depression is frequent in primary care, but correct diagnosis of these disorders is a challenge for general practitioners. Our current study describes the point prevalence of affective syndromes meeting DSM-IV criteria for depression in 984 adult patients visiting primary care practices. General practitioners applied the Beck Depression Inventory and the PRIME-MD screening tool. In case of all depressive disorders according to DSM-IV criteria (major depression, major depression in partial remission, dysthymia, minor depression) current prevalence rate was 18.5%, while point prevalence of only major depressive episode was 7.3%. Using the Beck Depression Inventory, general practitioners could diagnose current depression with a sensitivity of 95% and a specificity of 56%, while in case of major depressive episode sensitivity was 83% and specificity was 23%. These results parallel earlier data from Hungary as well as from other countries and they also support that the PRIME-MD and the Beck Depression Inventory may be a useful screening tool for depressive disorders in general practice. PMID:19419011

  4. Learning and memory impairments in a neuroendocrine mouse model of anxiety/depression

    PubMed Central

    Darcet, Flavie; Mendez-David, Indira; Tritschler, Laurent; Gardier, Alain M.; Guilloux, Jean-Philippe; David, Denis J.

    2014-01-01

    Cognitive disturbances are often reported as serious incapacitating symptoms by patients suffering from major depressive disorders (MDDs). Such deficits have been observed in various animal models based on environmental stress. Here, we performed a complete characterization of cognitive functions in a neuroendocrine mouse model of depression based on a chronic (4 weeks) corticosterone administration (CORT). Cognitive performances were assessed using behavioral tests measuring episodic (novel object recognition test, NORT), associative (one-trial contextual fear conditioning, CFC), and visuo-spatial (Morris water maze, MWM; Barnes maze, BM) learning/memory. Altered emotional phenotype after chronic corticosterone treatment was confirmed in mice using tests predictive of anxiety or depression-related behaviors. In the NORT, CORT-treated mice showed a decrease in time exploring the novel object during the test session and a lower discrimination index compared to control mice, characteristic of recognition memory impairment. Associative memory was also impaired, as observed with a decrease in freezing duration in CORT-treated mice in the CFC, thus pointing out the cognitive alterations in this model. In the MWM and in the BM, spatial learning performance but also short-term spatial memory were altered in CORT-treated mice. In the MWM, unlike control animals, CORT-treated animals failed to learn a new location during the reversal phase, suggesting a loss of cognitive flexibility. Finally, in the BM, the lack of preference for the target quadrant during the recall probe trial in animals receiving corticosterone regimen demonstrates that long-term retention was also affected in this paradigm. Taken together, our results highlight that CORT-induced anxio-depressive-like phenotype is associated with a cognitive deficit affecting all aspects of memory tested. PMID:24822041

  5. Learning and memory impairments in a neuroendocrine mouse model of anxiety/depression.

    PubMed

    Darcet, Flavie; Mendez-David, Indira; Tritschler, Laurent; Gardier, Alain M; Guilloux, Jean-Philippe; David, Denis J

    2014-01-01

    Cognitive disturbances are often reported as serious incapacitating symptoms by patients suffering from major depressive disorders (MDDs). Such deficits have been observed in various animal models based on environmental stress. Here, we performed a complete characterization of cognitive functions in a neuroendocrine mouse model of depression based on a chronic (4 weeks) corticosterone administration (CORT). Cognitive performances were assessed using behavioral tests measuring episodic (novel object recognition test, NORT), associative (one-trial contextual fear conditioning, CFC), and visuo-spatial (Morris water maze, MWM; Barnes maze, BM) learning/memory. Altered emotional phenotype after chronic corticosterone treatment was confirmed in mice using tests predictive of anxiety or depression-related behaviors. In the NORT, CORT-treated mice showed a decrease in time exploring the novel object during the test session and a lower discrimination index compared to control mice, characteristic of recognition memory impairment. Associative memory was also impaired, as observed with a decrease in freezing duration in CORT-treated mice in the CFC, thus pointing out the cognitive alterations in this model. In the MWM and in the BM, spatial learning performance but also short-term spatial memory were altered in CORT-treated mice. In the MWM, unlike control animals, CORT-treated animals failed to learn a new location during the reversal phase, suggesting a loss of cognitive flexibility. Finally, in the BM, the lack of preference for the target quadrant during the recall probe trial in animals receiving corticosterone regimen demonstrates that long-term retention was also affected in this paradigm. Taken together, our results highlight that CORT-induced anxio-depressive-like phenotype is associated with a cognitive deficit affecting all aspects of memory tested. PMID:24822041

  6. New particle dependant parameterizations of heterogeneous freezing processes.

    NASA Astrophysics Data System (ADS)

    Diehl, Karoline; Mitra, Subir K.

    2014-05-01

    For detailed investigations of cloud microphysical processes an adiabatic air parcel model with entrainment is used. It represents a spectral bin model which explicitly solves the microphysical equations. The initiation of the ice phase is parameterized and describes the effects of different types of ice nuclei (mineral dust, soot, biological particles) in immersion, contact, and deposition modes. As part of the research group INUIT (Ice Nuclei research UnIT), existing parameterizations have been modified for the present studies and new parameterizations have been developed mainly on the basis of the outcome of INUIT experiments. Deposition freezing in the model is dependant on the presence of dry particles and on ice supersaturation. The description of contact freezing combines the collision kernel of dry particles with the fraction of frozen drops as function of temperature and particle size. A new parameterization of immersion freezing has been coupled to the mass of insoluble particles contained in the drops using measured numbers of ice active sites per unit mass. Sensitivity studies have been performed with a convective temperature and dew point profile and with two dry aerosol particle number size distributions. Single and coupled freezing processes are studied with different types of ice nuclei (e.g., bacteria, illite, kaolinite, feldspar). The strength of convection is varied so that the simulated cloud reaches different levels of temperature. As a parameter to evaluate the results the ice water fraction is selected which is defined as the relation of the ice water content to the total water content. Ice water fractions between 0.1 and 0.9 represent mixed-phase clouds, larger than 0.9 ice clouds. The results indicate the sensitive parameters for the formation of mixed-phase and ice clouds are: 1. broad particle number size distribution with high number of small particles, 2. temperatures below -25°C, 3. specific mineral dust particles as ice nuclei such as illite or montmorillonite. Coupled cases of deposition and contact freezing show that they are hardly in competition because of differences in the preferred particle sizes. In the contact mode, small particles are less efficient for collisions as well as less efficient as ice nuclei so that these are available for deposition freezing. On the other hand, immersion freezing is the dominant process when it is coupled with deposition freezing. As it is initiated earlier the formed ice particles consume water vapor for growing. The competition of combined contact and immersion freezing leads to lower ice water contents because more ice particles are formed via the immersion mode. In general, ice clouds and mixed-phase clouds with high ice water fractions are not directly the result of primary ice formation but of secondary ice formation and growth of ice particles at the expense of liquid drops.

  7. Gullied Depression

    NASA Technical Reports Server (NTRS)

    2006-01-01

    26 February 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows gullies formed in the wall of a depression located on the floor of Rabe Crater west of the giant impact basin, Hellas Planitia. Gullies such as these are common features on Mars, but the process by which they are formed is not fully understood. The debate centers on the role and source of fluids in the genesis of these features.

    Location near: 44.1oS, 325.9oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

  8. Exploring the Nature of Contact Freezing

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    The freezing of supercooled water droplets upon contact with aerosol particles (contact nucleation of ice) is the least understood mechanism of ice formation in atmospheric clouds. Although experimental evidences suggest that some aerosols can be better IN in the contact than in the immersion mode (that is, triggering ice nucleation at higher temperature), no final explanation of this phenomena currently exists. On the other hand, the contact freezing is believed to be responsible for the enhanced rate of secondary ice formation occasionally observed in LIDAR measurements in the cold mixed phase clouds. Recently we have been able to show that the freezing of supercooled droplets electrodynamically levitated in the laminar flow containing mineral dust particles (kaolinite) is a process solely governed by a rate of collisions between the supercooled droplet and the aerosol particles. We have shown that the probability of droplet freezing on a single contact with aerosol particle may differ over an order of magnitude for kaolinite particles having different genesis and morphology. In this presentation we extend the study of contact nucleation of ice and compare the IN efficiency measured for DMA-selected kaolinite, illite and hematite particles. We show that the freezing probability increases towards unity as the temperature decreases and discuss the functional form of this temperature dependence. We explore the size dependence of the contact freezing probability and show that it scales with the surface area of the particles, thus resembling the immersion freezing behavior. However, for all minerals investigated so far, the contact freezing has been shown to dominate over immersion freezing on the short experimental time scales. Finally, based on the combined ESEM and electron microprobe analysis, we discuss the significance of particle morphology and variability of chemical composition on its IN efficiency in contact mode.

  9. Freeze Denaturation of Fish Muscle Proteins

    NASA Astrophysics Data System (ADS)

    Tsuchiya, Takahide

    Studies on the freeze denaturation of fish muscle proteins were reviewed with emphasis given to changes in their physicochemical and biochemical properties during frozen storage. Denaturation of actomyosin commonly occurs during frozen storage and side-to-side aggregation of myosin molecules apppears to major role in this reaction. The author's group performed freezing studies with isolated preparations of proteins from carp muscle, namely actomyosin, myosin, H-meromyosin, L-meromyosin, and actin. Freeze denaturation occurred with indvidual proteins as well as with their subunits. Not only aggregation but also some conformational changes were observed. Denaturation was inhibited in the presence of added glutamate.

  10. Depression at adolescence

    Microsoft Academic Search

    N. Zdanowicz; E. Coremans; C. Reynaert; Mark Stemmler; Sydney Ey; Kathryn E. Grant

    2002-01-01

    BACKGROUND Mental disorders affect young people disproportionately and are increasing in prevalence. Knowledge about depression in adolescents and skill in its management lags behind that for adults. Depression is the most common mental disorder and untreated depression is associated with significant adverse effects. Depression is also a major predictor of suicidal behaviour and suicide. The role of the general practitioner

  11. Depression and College Students

    E-print Network

    Kane, Andrew S.

    Depression and College Students Answers to college students' frequently asked questions about depression #12;2 M any people experience the first symptoms of depression during their college years. Unfortunately, many college students who have depression aren't getting the help they need. They may not know

  12. The Great Depression

    NSDL National Science Digital Library

    RandyandAmber

    2007-11-30

    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. ...

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

    PubMed Central

    Wang, Yuan-Pang; Gorenstein, Clarice

    2013-01-01

    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. PMID:24141845

  14. Freeze concentration beats the heat

    SciTech Connect

    Rosen, J.

    1990-12-01

    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 juices were found to be superior in taste to juices produced by evaporation and similar to the original pasteurized juices. The dairy industry, which is the largest user of energy for concentration in the food sector, is looking to FC for new products such as frozen concentrated milk as well as better use of the milk by-products of cheese production. The biggest potential for new FC applications is in those industries that consume large amounts of energy for separation processing, according to a 1987 report prepared for EPRI. In the food industry, this includes milk, vinegar, and beer producers. Potential applications also abound in the pulp and paper, pharmaceutical, chemical, and petroleum industries. FC separates substances via crystallization at substantial energy savings.

  15. [Depression and somatic comorbidity].

    PubMed

    Penninx, Brenda W J H; van Dyck, Richard

    2010-01-01

    Depressed persons have a higher risk of developing somatic conditions such as cardiovascular disease, diabetes and obesity. Somatic comorbidity in depressed persons may be explained by mediating mechanisms such as unhealthy lifestyle and unfavorable pathophysiological disturbances. There are alternative explanations for somatic comorbidity in depressed persons: genetic pleiotropy, iatrogenic effects, and the phenomenon 'somatic depression'. In the latter, the symptoms of depression are a consequence of clinical or subclinical somatic conditions. When treating a depressed patient, their somatic health should also be monitored. Further research is needed to examine whether specific interventions may prevent somatic comorbidity in depression. PMID:20456788

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

    NASA Astrophysics Data System (ADS)

    Marshall, Katie E.; Sinclair, Brent J.

    2012-01-01

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

  17. Simulations of Polar Stratospheric Clouds and Denitrification Using Laboratory Freezing Rates

    NASA Technical Reports Server (NTRS)

    Drdla, Katja; Tabazadeh, Azadeh; Gore, Warren J. (Technical Monitor)

    2001-01-01

    During the 1999-2000 Arctic winter, the SAGE (Stratospheric Aerosol and Gas Experiment) III Ozone Loss and Validation Experiment (SOLVE) provided evidence of widespread solid-phase polar stratospheric clouds (PSCs) accompanied by severe nitrification. Previous simulations have shown that a freezing process occurring at temperatures above the ice frost point is necessary to explain these observations. In this work, the nitric acid freezing rates measured by Salcedo et al. and discussed by Tabazadeh et al. have been examined. These freezing rates have been tested in winter-long microphysical simulations of the 1999-2000 Arctic vortex evolution in order to determine whether they can explain the observations. A range of cases have been explored, including whether the PSC particles are composed of nitric acid dihydrate or trihydrate, whether the freezing process is a bulk process or occurs only on the particle surfaces, and uncertainties in the derived freezing rates. Finally, the possibility that meteoritic debris enhances the freezing rate has also been examined. The results of these simulations have been compared with key PSC and denitrification measurements made by the SOLVE campaign. The cases that best reproduce the measurements will he highlighted, with a discussion of the implications for our understanding of PSCs.

  18. Research on the Effect of Electric Charge on Initiation of Freezing of Supercooled Water

    NASA Astrophysics Data System (ADS)

    Okawa, Seiji; Saito, Akio; Fukao, Takeshi

    The effect of applying the electric charge on the freezing of supercooled water was investigated using a pair of spherical electrodes, facing to each other in the test water. The reason for using a spherical end surface was to minimize unexpected high electrical density on the surface due to the existence of a singular point. After getting a uniform temperature, D. C. voltage was applied to the test section. Temperature, distance between two electrode sand the voltage applied were varied. It was found that supercooled water freeze in a few seconds after applying the electric charge. It was also found that the freezing is a statistical phenomenon. There are some tendencies, however, that the higher the value of D. C. voltage applied or the closer the distance between two electrodes are, the easier the water freeze. The electrical current was measured for every 0.05 seconds and it was found that the value increased while the voltage was being applied. The idea of a probability of freezing while a specific current flows for a time interval of ?t was introduced. The probability of freezing was calculated under two different conditions and the results were compared to each other to confirm the assumption. As a result, it was concluded that the probability depends only on the past record of current flow.

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

    PubMed

    Lee, Juliana Tsz Yan; Chow, King Lau

    2012-01-01

    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

  20. Supercooling and Freezing in Winter Dormant Animals

    NSDL National Science Digital Library

    William D. Schmid (University of Minnesota; )

    1988-01-01

    This resource is a manual for instructing students in a laboratory exercise examining the effects of winter-time supercooling and freezing on animals. This lab would be a suitable supplement to animal physiology or physiological ecology courses.

  1. Freeze Crystallization Processes: Efficiency by Flexibility

    E-print Network

    Heist, J. A.; Barron, T. S.

    1983-01-01

    Energy consumption in fractionating solutions by distillation and evaporation can be reduced by 70% to 90% by using freeze crystallization processes. The thermodynamic bases for the substantially lower energy requirements include: 1) The phase...

  2. Freezing tolerance of conifer seeds and germinants.

    PubMed

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

    2003-12-01

    Survival after freezing was measured for seeds and germinants of four seedlots each of interior spruce (Picea glauca x engelmannii complex), lodgepole pine (Pinus contorta Dougl. ex Loud.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western red cedar (Thuja plicata Donn ex D. Donn). Effects of eight seed treatments on post-freezing survival of seeds and germinants were tested: dry, imbibed and stratified seed, and seed placed in a growth chamber for 2, 5, 10, 15, 20 or 30 days in a 16-h photoperiod and a 22/17 degrees C thermoperiod. Survival was related to the water content of seeds and germinants, germination rate and seedlot origin. After freezing for 3 h at -196 degrees C, dry seed of most seedlots of interior spruce, Douglas-fir and western red cedar had 84-96% germination, whereas lodgepole pine seedlots had 53-82% germination. Freezing tolerance declined significantly after imbibition in lodgepole pine, Douglas-fir and interior spruce seed (western red cedar was not tested), and mean LT50 of imbibed seed of these species was -30, -24.5 and -20 degrees C, respectively. Freezing tolerance continued to decline to a minimum LT50 of -4 to -7 degrees C after 10 days in a growth chamber for interior spruce, Douglas-fir and lodgepole pine, or after 15 days for western red cedar. Minimum freezing tolerance was reached at the stage of rapid hypocotyl elongation. In all species, a slight increase in freezing tolerance of germinants was observed once cotyledons emerged from the seed coat. The decrease in freezing tolerance during the transition from dry to germinating seed correlated with increases in seed water content. Changes in freezing tolerance between 10 and 30 days in the growth chamber were not correlated with seedling water content. Within a species, seedlots differed significantly in freezing tolerance after 2 or 5 days in the growth chamber. Because all seedlots of interior spruce and lodgepole pine germinated quickly, there was no correlation between seedlot hardiness and rate of germination. Germination rate and freezing tolerance of Douglas-fir and western red cedar seedlots was negatively correlated. There was a significant correlation between LT50 after 10 days in the growth chamber and minimum spring temperature at the location of seedlot origin for interior spruce and three seedlots of western red cedar, but no relationship was apparent for lodgepole pine and Douglas-fir. PMID:14652223

  3. Freezing and Thawing Human Embryonic Stem Cells

    NSDL National Science Digital Library

    Kent, Lia

    Lia Kent, of Stemgent's Research and Development team, has created this video to demonstrate "the proper technique for rapidly thawing hES cells from liquid nitrogen stocks, plating them on mouse embryonic feeder cells, and slowly freezing them for long-term storage." The video is also accompanied by protocols for thawing and freezing hES cells, discussion, materials, references, a forum for comments, and a PDF of the full text.

  4. Freezing Characteristics of Rigid Plant Tissues (Development of Cell Tension during Extracellular Freezing).

    PubMed Central

    Rajashekar, C. B.; Burke, M. J.

    1996-01-01

    The freezing characteristics and development of cell tension during extracellular freezing were examined in supercooling stem tissues of riverbank grapes (Vitis riparia) and cold-hardened leaves of live oak (Quercus virginiana) and mountain cranberry (Vaccinium vitis-idaea). Dormant stem xylem and pith tissues of river-bank grapes were resistant to freeze-induced dehydration above the homogeneous nucleation temperature, and they developed cell tension reaching a maximum of 27 MPa. Similarly, extracellular freezing induced cell tension in the leaves of live oak and mountain cranberry. Maximum cell tension in the leaves of live oak was 16.8 MPa and 8.3 MPa in the leaves of mountain cranberry. Following peak tensions in the leaves, a decline in the pressure was observed with progressive freezing. The results suggest that resistance to cell deformation during extracellular freezing due to cell-wall rigidity can lead to reduced cell dehydration and increased cell tension. A relationship to predict freezing behavior in plant tissues based on cell rigidity is presented. Based on cell-water relations and ice nucleation rates, cell-wall rigidity has been shown to effect the freezing characteristics of plant tissues, including freeze-induced dehydration, supercooling, and homogeneous nucleation temperatures. PMID:12226313

  5. Composition and freezing of aqueous H2SO4/HNO3 solutions under polar stratospheric conditions

    NASA Technical Reports Server (NTRS)

    Beyer, K. D.; Seago, S. W.; Chang, H. Y.; Molina, M. J.

    1994-01-01

    The results of laboratory investigations of the freezing behavior of aqueous acid solutions indicate that in the stratosphere H2SO/H2O aerosol droplets would not freeze at temperatures above the ice frost point in the absence of HNO3; however, in the presence of typical levels of HNO3 liquid sulfuric acid aerosols take up significant amounts of HNO3 and H2O vapors and freeze much more readily. This is a consequence of the very rapid change in composition of the liquid droplets as the temperature drops to within two to three degrees of the equilibrium temperature at which HNO3 and H2O vapors would co-condense to form a liquid solution. In the high latitude stratosphere this HNO3/H2O 'dew point' is typically around 192-194 K at 100 mbar.

  6. Historical recollections of freeze-drying.

    PubMed

    Meryman, H T

    1976-10-01

    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

  7. Freezing of living cells: mechanisms and implications.

    PubMed

    Mazur, P

    1984-09-01

    Cells can endure storage at low temperatures such as--196 degrees 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. PMID:6383068

  8. Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger with Bypass Setpoint Temperature Control

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.

    2008-01-01

    Spacecraft radiators are sized for their maximum heat load in their warmest thermal environment, but must operate at reduced heat loads and in colder environments. For systems where the radiator environment can be colder than the working fluid freezing temperature, radiator freezing becomes an issue. Radiator freezing has not been a major issue for the Space Shuttle and the International Space Station (ISS) active thermal control systems (ATCSs) because they operate in environments that are warm relative to the freezing point of their external coolants (Freon-21 and ammonia, respectively). For a vehicle that lands at the Lunar South Pole, the design thermal environment is 215K, but the radiator working fluid must also be kept from freezing during the 0 K sink of transit. A radiator bypass flow control design such as those used on the Space Shuttle and ISS requires more than 30% of the design heat load to avoid radiator freezing during transit - even with a very low freezing point working fluid. By changing the traditional ATCS architecture to include a regenerating heat exchanger inboard of the radiator and by using a regenerator bypass flow control valve to maintain system setpoint, the required minimum heat load can be reduced by more than half. This gives the spacecraft much more flexibility in design and operation. The present work describes the regenerator bypass ATCS setpoint control methodology. It includes analytical results comparing the performance of this system to the traditional radiator bypass system. Finally, a summary of the advantages of the regenerator bypass system are presented.

  9. Depression and Spinal Cord Injury

    MedlinePLUS

    ... Urinary Tract Infections: Indwelling (Foley) Catheter Depression and Spinal Cord Injury [ Download this pamphlet: “Depression and Spinal Cord Injury” (PDF - 477KB)] Depression is a common illness that ...

  10. Motor Imagery in Unipolar Major Depression

    PubMed Central

    Bennabi, Djamila; Monnin, Julie; Haffen, Emmanuel; Carvalho, Nicolas; Vandel, Pierre; Pozzo, Thierry; Papaxanthis, Charalambos

    2014-01-01

    Background: Motor imagery is a potential tool to investigate action representation, as it can provide insights into the processes of action planning and preparation. Recent studies suggest that depressed patients present specific impairment in mental rotation. The present study was designed to investigate the influence of unipolar depression on motor imagery ability. Methods: Fourteen right-handed patients meeting DSM-IV criteria for unipolar depression were compared to 14 matched healthy controls. Imagery ability was accessed by the timing correspondence between executed and imagined movements during a pointing task, involving strong spatiotemporal constraints (speed/accuracy trade-off paradigm). Results: Compared to controls, depressed patients showed marked motor slowing on both actual and imagined movements. Furthermore, we observed greater temporal discrepancies between actual and mental movements in depressed patients than in healthy controls. Lastly, depressed patients modulated, to some extent, mental movement durations according to the difficulty of the task, but this modulation was not as strong as that of healthy subjects. Conclusion: These results suggest that unipolar depression significantly affects the higher stages of action planning and point out a selective decline of motor prediction. PMID:25538580

  11. Freeze Tolerance of Nine Zoysiagrass Cultivars Using Natural Cold Acclimation and Freeze Chambers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter hardiness of zoysiagrass (Zoysia spp.) cultivars is an important attribute throughout the biogeographical transition zone, thus the inability to withstand freezing temperatures may limit the use of these cultivars. The objective of this research was to determine the freeze tolerance (LT50) of...

  12. Sleep disorders as core symptoms of depression.

    PubMed

    Nutt, David; Wilson, Sue; Paterson, Louise

    2008-01-01

    Links between sleep and depression are strong. About three quarters of depressed patients have insomnia symptoms, and hypersomnia is present in about 40% of young depressed adults and 10% of older patients, with a preponderance in females. The symptoms cause huge distress, have a major impact on quality of life, and are a strong risk factor for suicide. As well as the subjective experience of sleep symptoms, there are well-documented changes in objective sleep architecture in depression. Mechanisms of sleep regulation and how they might be disturbed in depression are discussed. The sleep symptoms are often unresolved by treatment, and confer a greater risk of relapse and recurrence. Epidemiological studies have pointed out that insomnia in nondepressed subjects is a risk factor for later development of depression. There is therefore a need for more successful management of sleep disturbance in depression, in order to improve quality of life in these patients and reduce an important factor in depressive relapse and recurrence. PMID:18979946

  13. Field Response of Sugarcane Genotypes to Freeze Stress with Genotype x Environment Effects on Quality Traits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Freeze stress is a constraint to sugarcane (Saccharum sp.) with negative effect on sucrose yield, particularly during the harvest season. To understand its impact on the performance of genotypes developed by the Canal Point (CP) breeding program, the genotype by environment (GxE) interaction was app...

  14. [Emotional reactivity of patients with depression].

    PubMed

    Mikha?lova, E S; Monosova, A Zh; Beliaev, B S

    1990-01-01

    Emotional reactivity of patients with endogenous depression and healthy test subjects towards classic and rock music was compared. According to the questionnaire data and EEG recording, it was established that in depressed patients, analysis and estimation of the emotionally significant information differ from those in healthy persons. In contrast to normals, the classic music exerts an activation effect on the patients whereas rock music evokes negative emotions. Analysis of the time-course of changes in the EEG points to alterations in the system of nonspecific activation in depressions. PMID:2167595

  15. Ethnocultural Differences in Prevalence of Adolescent Depression

    Microsoft Academic Search

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

    1997-01-01

    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%

  16. Freezing, melting and structure of ice in a hydrophilic nanopore.

    PubMed

    Moore, Emily B; de la Llave, Ezequiel; Welke, Kai; Scherlis, Damian A; Molinero, Valeria

    2010-04-28

    The nucleation, growth, structure and melting of ice in 3 nm diameter hydrophilic nanopores are studied through molecular dynamics simulations with the mW water model. The melting temperature of water in the pore was T(m)(pore) = 223 K, 51 K lower than the melting point of bulk water in the model and in excellent agreement with experimental determinations for 3 nm silica pores. Liquid and ice coexist in equilibrium at the melting point and down to temperatures as low as 180 K. Liquid water is located at the interface of the pore wall, increasing from one monolayer at the freezing temperature, T(f)(pore) = 195 K, to two monolayers a few degrees below T(m)(pore). Crystallization of ice in the pore occurs through homogeneous nucleation. At the freezing temperature, the critical nucleus contains approximately 75 to 100 molecules, with a radius of gyration similar to the radius of the pore. The critical nuclei contain features of both cubic and hexagonal ice, although stacking of hexagonal and cubic layers is not defined until the nuclei reach approximately 150 molecules. The structure of the confined ice is rich in stacking faults, in agreement with the interpretation of X-ray and neutron diffraction experiments. Though the presence of cubic layers is twice as prevalent as hexagonal ones, the crystals should not be considered defective Ic as sequences with more than three adjacent cubic (or hexagonal) layers are extremely rare in the confined ice. PMID:20379503

  17. [Alzheimer's disease and depression].

    PubMed

    Mizukami, Katsuyoshi

    2013-01-01

    In Alzheimer's disease (AD) patients, depression is not rare. The prevalence of major depressive episodes has been reported to be within the range of 20-25% in AD patients, despite there being no association between the severity of AD and prevalence of comorbid depressive symptoms or diagnosed depression. Depression in AD patients is associated with greater impairment of the quality of life and an increased caregiver burden. As well as earlier placement in a nursing home, bio-psycho-social factors are also associated with the manifestation of depression in AD patients, and biological factors, such as the brain pathology, may be the main influence. Depressive mood, loss of interest, and anxiety are among the most marked symptoms of depression in AD patients. In comparison with major depressive disorder, in depression in AD, psychomotor retardation is more prominent, while, in major depressive disorder, somatic anxiety is more marked. In the treatment of depression in AD, non-pharmacological and pharmacological therapies are applied. Basically, support and encouragement are required. In addition, psychosocial interventions, such as validation, reminiscence, physical exercise, and interventions for caregivers of those with dementia have been reported to be useful. The results of RCT with antidepressants are inconsistent. As the efficacy of cholinesterase inhibitor for depression in AD has been reported, it is reasonable to initially provide treatment with cholinesterase inhibitors rather than antidepressant therapy. PMID:24450144

  18. Freeze-drying of lactic acid bacteria.

    PubMed

    Fonseca, Fernanda; Cenard, Stéphanie; Passot, Stéphanie

    2015-01-01

    Lactic acid bacteria are of great importance for the food and biotechnology industry. They are widely used as starters for manufacturing food (e.g., yogurt, cheese, fermented meats, and vegetables) and probiotic products, as well as for green chemistry applications. Freeze-drying or lyophilization is a convenient method for preservation of bacteria. By reducing water activity to values below 0.2, it allows long-term storage and low-cost distribution at suprazero temperatures, while minimizing losses in viability and functionality. Stabilization of bacteria via freeze-drying starts with the addition of a protectant solution to the bacterial suspension. Freeze-drying includes three steps, namely, (1) freezing of the concentrated and protected cell suspension, (2) primary drying to remove ice by sublimation, and (3) secondary drying to remove unfrozen water by desorption. In this chapter we describe a method for freeze-drying of lactic acid bacteria at a pilot scale, thus allowing control of the process parameters for maximal survival and functionality recovery. PMID:25428024

  19. 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, ...

  20. Freeze drying for morphological control of inter-penetrating polymer networks

    NASA Technical Reports Server (NTRS)

    Hansen, Marion G.; Pater, Ruth H.

    1990-01-01

    The intrinsic brittleness of BMI resins can be reduced through the creation of an interpenetrating network (IPN) of BMI with a reactive-encapped thermoplastic, such as the presently considered polyimidesulfone, PISO2. The PISO2 and BMI were dissolved in a common solvent, which was then removed from the constituents by freeze drying; in an alternative method, an IPN was formed through dissolution of the constituent in a common solvent with either high or low melting point, followed by evaporative removal of the solvent. The effectiveness of the freeze-drying approach for morphological control is evaluated.

  1. Depression and Multiple Sclerosis

    MedlinePLUS

    ... grieving Depression is often hard to distinguish from grief. Persons with MS may experience losses — for example ... mourning for these losses may resemble depression. However, grief is generally time-limited and resolves on its ...

  2. Depression and College Students

    MedlinePLUS

    ... depression? A. Depression is a common but serious mental illness typically marked by sad or anxious feelings. Most ... a mental health care professional to treat a mental illness. Types of psychotherapy that have been shown to ...

  3. Depression and Exercise

    Microsoft Academic Search

    Jerome Sarris; David J Kavanagh; Robert U Newton

    2008-01-01

    With the efficacy of antidepressants under a question mark, many depressed patients are turning to common sense remedies such as exercise. Increasing activity not only has physical effects that lift a depressive mood: it can be fun as well.

  4. Background to Depression

    NSDL National Science Digital Library

    2009-04-14

    Although writers have described episodes of depression since antiquity, only recently have we recognized that the depressive disorders are among the most common and disabling medical conditions throughout the world.

  5. Depression and Heart Disease

    MedlinePLUS

    ... see the NIMH booklet on Depression . What is heart disease? Heart disease refers to a number of ... and save your life. How are depression and heart disease linked? People with heart disease are more ...

  6. Depression and African Americans

    MedlinePLUS

    ... depressive illness. According to a Surgeon General report, African Americans are over-represented in populations that are particularly ... not a normal part of life for any African American, regardless of age or life situation. Unfortunately, depression ...

  7. Depression and Asthma

    MedlinePLUS Videos and Cool Tools

    ... Pages Asthma in Children Depression Health Problems in Pregnancy Transcript Depression during pregnancy may increase the risk of asthma in children, ... their children, but the use of antidepressants during pregnancy generally did not up the risk. An association ...

  8. Cognitive deficits in depression

    E-print Network

    Haines, Mary Ellen

    1993-01-01

    with depression that these studies consistently showed a correlation between depression and impaired functioning on various cognitive tasks such as the Wechsler Adult Intelligence Scales subtests of Block Design, Object Assembly and Digit Symbol (WAIS...

  9. Major Depression Among Adults

    MedlinePLUS

    Major depression is one of the most common mental disorders in the United States. According to the World Health Organization (WHO; 2010), major depression also carries the heaviest burden of disability among mental ...

  10. Depression and Chronic Illness

    MedlinePLUS

    ... and one-fifth with terminal cancer experience a depressive disorder. Sadly, less than half of those receive treatment for depression. Facing a chronic illness naturally leads to feelings of uncertainty, grief, sadness, anger or fear. But when these feelings ...

  11. Postpartum Depression Action Plan

    MedlinePLUS

    MENU Return to Web version Postpartum Depression | Postpartum Depression Action Plan Patient __________________________ Physician/NP/PA __________________ Clinic ____________________________ Phone Number ____________________ Choose one area and add other areas as you begin ...

  12. UltraViolet freeze-in

    NASA Astrophysics Data System (ADS)

    Elahi, Fatemeh; Kolda, Christopher; Unwin, James

    2015-03-01

    If dark matter is thermally decoupled from the visible sector, the observed relic density can potentially be obtained via freeze-in production of dark matter. Typically in such models it is assumed that the dark matter is connected to the thermal bath through feeble renormalisable interactions. Here, rather, we consider the case in which the hidden and visible sectors are coupled only via non-renormalisable operators. This is arguably a more generic realisation of the dark matter freeze-in scenario, as it does not require the introduction of diminutive renormalisable couplings. We examine general aspects of freeze-in via non-renormalisable operators in a number of toy models and present several motivated implementations in the context of Beyond the Standard Model (BSM) physics. Specifically, we study models related to the Peccei-Quinn mechanism and Z ' portals.

  13. Freeze verification: time for a fresh approach

    SciTech Connect

    Paine, C.

    1983-01-01

    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)

  14. Heat transfer coefficient of cryotop during freezing.

    PubMed

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

    2013-01-01

    Cryotop is an efficient vitrification method for cryopreservation of oocytes. It has been widely used owing to its simple operation and high freezing rate. Recently, the heat transfer performance of cryotop was studied by numerical simulation in several studies. However, the range of heat transfer coefficient in the simulation is uncertain. In this study, the heat transfer coefficient for cryotop during freezing process was analyzed. The cooling rates of 40 percent ethylene glycol (EG) droplet in cryotop during freezing were measured by ultra-fast measurement system and calculated by numerical simulation at different value of heat transfer coefficient. Compared with the results obtained by two methods, the range of the heat transfer coefficient necessary for the numerical simulation of cryotop was determined, which is between 9000 W/(m(2)·K) and 10000 W/(m (2)·K). PMID:23812315

  15. Method of treating depression

    DOEpatents

    Henn, Fritz

    2013-04-09

    Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.

  16. Method of treating depression

    DOEpatents

    Henn, Fritz (East Patchogue, NY)

    2012-01-24

    Methods for treatment of depression-related mood disorders in mammals, particularly humans are disclosed. The methods of the invention include administration of compounds capable of enhancing glutamate transporter activity in the brain of mammals suffering from depression. ATP-sensitive K.sup.+ channel openers and .beta.-lactam antibiotics are used to enhance glutamate transport and to treat depression-related mood disorders and depressive symptoms.

  17. Depression on Dialysis

    Microsoft Academic Search

    Joseph Chilcot; David Wellsted; Maria Da Silva-Gane; Ken Farrington

    2008-01-01

    Depression is the most common psychopathological condition among patients with end-stage renal disease (ESRD), yet it is still under-recognized and misdiagnosed. Depression reduces quality of life and has a negative clinical impact upon sufferers with chronic illness, including ESRD. This article discusses the negative effects of depression among the ESRD population treated with dialysis, the prevalence of the condition, the

  18. Prevention of Depression.

    ERIC Educational Resources Information Center

    Compas, Bruce E.; Connor, Jennifer; Wadsworth, Martha

    Substantial numbers of children and adolescents experience symptoms of sadness, dysphoria, and other characteristics associated with depression. The nature of depression in children and adolescents has presented challenges in identification and definition. This chapter reviews research on depression in children and adolescents. Three current…

  19. Importance of Depression in Diabetes.

    ERIC Educational Resources Information Center

    Lustman, Patrick J.; Clouse, Ray E.; Anderson, Ryan J.

    Depression doubles the likelihood of comorbid depression, which presents as major depression in 11% and subsyndromal depression in 31% of patients with the medical illness. The course of depression is chronic, and afflicted patients suffer an average of one episode annually. Depression has unique importance in diabetes because of its association…

  20. Homogeneous freezing of single sulfuric and nitric acid solution drops levitated in an acoustic trap

    NASA Astrophysics Data System (ADS)

    Diehl, Karoline; Ettner-Mahl, Matthias; Hannemann, Anke; Mitra, Subir K.

    2009-10-01

    The freezing temperatures of single supercooled drops of binary and ternary sulfuric and nitric acid solutions were measured while varying the acid concentration. An acoustic levitator was used which allows to freely suspend single solution drops in air without electrical charges thereby avoiding any electrical influences which may affect the freezing process. The drops of typically 500 µm in radius were monitored by a video camera during cooling cycles down to - 85 °C to simulate the upper tropospheric and stratospheric temperature range. The present data confirm that liquid solution droplets can be supercooled far below the equilibrium melting point by approximately 35 °C. They follow the general trend of the expected freezing temperatures for homogeneous ice nucleation.

  1. Melting and freezing of argon in a granular packing of linear mesopore arrays

    E-print Network

    Christof Schaefer; Tommy Hofmann; Dirk Wallacher; Patrick Huber; Klaus Knorr

    2008-03-29

    Freezing and melting of Ar condensed in a granular packing of template-grown arrays of linear mesopores (SBA-15, mean pore diameter 8 nanometer) has been studied by specific heat measurements C as a function of fractional filling of the pores. While interfacial melting leads to a single melting peak in C, homogeneous and heterogeneous freezing along with a delayering transition for partial fillings of the pores result in a complex freezing mechanism explainable only by a consideration of regular adsorption sites (in the cylindrical mesopores) and irregular adsorption sites (in niches of the rough external surfaces of the grains, and at points of mutual contact of the powder grains). The tensile pressure release upon reaching bulk liquid/vapor coexistence quantitatively accounts for an upward shift of the melting/freeezing temperature observed while overfilling the mesopores.

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

    PubMed

    Costanzo, Jon P; Baker, Patrick J; Lee, Richard E

    2006-09-01

    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 not. Viability rates of hatchlings frozen to -3 degrees C for 72 h ranged from 0 to 100%. Tolerance to freezing was poor in Sternotherus odoratus, Graptemys geographica and Trachemys scripta, intermediate in Chelydra serpentina, and high in Emydoidea blandingii, Chrysemys picta bellii, C. p. marginata, Malaclemys terrapin, and Terrapene ornata, and generally reflected the winter thermal ecology of each taxon. Plasma activity of lactate dehydrogenase (LDH), a novel in vivo index of freeze/thaw damage, corroborated viability assessments and demonstrated that cryoinjury occurred even in surviving turtles. Irrespective of taxon, cryoinjury tended to be higher in smaller individuals and in those having relatively low water contents; however, bases for these associations were not apparent. Screening for certain organic osmolytes that might promote freezing survival by colligatively reducing ice content and limiting cell dehydration showed that the plasma of unfrozen (control) turtles contained small quantities of glucose (1.3-5.8 mmol l(-1)) and lactate (0.6-3.2 mmol l(-1)) and modest amounts of urea (range of mean values for all taxa 8.2-52.3 mmol l(-1)). Frozen/thawed turtles of all taxa accumulated modest amounts of glucose and lactate that jointly raised the plasma solute concentration by 30-100 mmol l(-1). We conclude that organic osmolytes accumulated both before and during freezing may promote survival in species that have evolved a tolerance to freezing, but are not necessarily accumulated for that purpose. PMID:16758216

  3. Infrared Thermography for Monitoring of Freeze-Drying Processes: Instrumental Developments and Preliminary Results

    PubMed Central

    Emteborg, Håkan; Zeleny, Reinhard; Charoud-Got, Jean; Martos, Gustavo; Lüddeke, Jörg; Schellin, Holger; Teipel, Katharina

    2014-01-01

    Coupling an infrared (IR) camera to a freeze dryer for on-line monitoring of freeze-drying cycles is described for the first time. Normally, product temperature is measured using a few invasive Pt-100 probes, resulting in poor spatial resolution. To overcome this, an IR camera was placed on a process-scale freeze dryer. Imaging took place every 120 s through a Germanium window comprising 30,000 measurement points obtained contact-free from ?40°C to 25°C. Results are presented for an empty system, bulk drying of cheese slurry, and drying of 1 mL human serum in 150 vials. During freezing of the empty system, differences of more than 5°C were measured on the shelf. Adding a tray to the empty system, a difference of more than 8°C was observed. These temperature differences probably cause different ice structures affecting the drying speed during sublimation. A temperature difference of maximum 13°C was observed in bulk mode during sublimation. When drying in vials, differences of more than 10°C were observed. Gradually, the large temperature differences disappeared during secondary drying and products were transformed into uniformly dry cakes. The experimental data show that the IR camera is a highly versatile on-line monitoring tool for different kinds of freeze-drying processes. © 2014 European Union 103:2088–2097, 2014 PMID:24902839

  4. Infrared thermography for monitoring of freeze-drying processes: instrumental developments and preliminary results.

    PubMed

    Emteborg, Håkan; Zeleny, Reinhard; Charoud-Got, Jean; Martos, Gustavo; Lüddeke, Jörg; Schellin, Holger; Teipel, Katharina

    2014-07-01

    Coupling an infrared (IR) camera to a freeze dryer for on-line monitoring of freeze-drying cycles is described for the first time. Normally, product temperature is measured using a few invasive Pt-100 probes, resulting in poor spatial resolution. To overcome this, an IR camera was placed on a process-scale freeze dryer. Imaging took place every 120 s through a Germanium window comprising 30,000 measurement points obtained contact-free from -40 °C to 25 °C. Results are presented for an empty system, bulk drying of cheese slurry, and drying of 1 mL human serum in 150 vials. During freezing of the empty system, differences of more than 5 °C were measured on the shelf. Adding a tray to the empty system, a difference of more than 8 °C was observed. These temperature differences probably cause different ice structures affecting the drying speed during sublimation. A temperature difference of maximum 13 °C was observed in bulk mode during sublimation. When drying in vials, differences of more than 10 °C were observed. Gradually, the large temperature differences disappeared during secondary drying and products were transformed into uniformly dry cakes. The experimental data show that the IR camera is a highly versatile on-line monitoring tool for different kinds of freeze-drying processes. PMID:24902839

  5. [Depression and diet ].

    PubMed

    Seppälä, Jussi; Kauppinen, Anne; Kautiainen, Hannu; Vanhala, Mauno; Koponen, Hannu

    2014-01-01

    Especially low vitamin B12 or folate and low intake of omega-3-fatty acids, but also low vitamin D may associate with increased risk of depression. B12 and folate may also be useful in the treatment of depression. The importance of individual fatty acids is unclear. The causal relationship between depression and diet, the efficacy of vitamins or dietary supplements in the treatment of depression, or the impact of diet compared with other treatment options need to be scrutinized. An overall healthy diet rich in vitamin B12, D or folate and fish oils may have positive effect also on depression. PMID:24881142

  6. Depressive symptoms in institutionalized older adults

    PubMed Central

    Santiago, Lívia Maria; Mattos, Inês Echenique

    2014-01-01

    OBJECTIVE To estimate the prevalence of depressive symptoms among institutionalized elderly individuals and to analyze factors associated with this condition. METHODS This was a cross-sectional study involving 462 individuals aged 60 or older, residents in long stay institutions in four Brazilian municipalities. The dependent variable was assessed using the 15-item Geriatric Depression Scale. Poisson’s regression was used to evaluate associations with co-variables. We investigated which variables were most relevant in terms of presence of depressive symptoms within the studied context through factor analysis. RESULTS Prevalence of depressive symptoms was 48.7%. The variables associated with depressive symptoms were: regular/bad/very bad self-rated health; comorbidities; hospitalizations; and lack of friends in the institution. Five components accounted for 49.2% of total variance of the sample: functioning, social support, sensory deficiency, institutionalization and health conditions. In the factor analysis, functionality and social support were the components which explained a large part of observed variance. CONCLUSIONS A high prevalence of depressive symptoms, with significant variation in distribution, was observed. Such results emphasize the importance of health conditions and functioning for institutionalized older individuals developing depression. They also point to the importance of providing opportunities for interaction among institutionalized individuals. PMID:24897042

  7. Nucleation Pathways For Freezing Of Two Grades Of Zirconium

    NASA Technical Reports Server (NTRS)

    Rhim, Won-Kyu; Rulison, Aaron; Bayuzick, Robert; Hofmeister, William; Morton, Craig

    1996-01-01

    Report discusses classical nucleation theory of freezing and describes experimental study of nucleation mechanisms that predominate during freezing of spherical specimens of initially molten zirconium levitated electrostatically in vacuum.

  8. 7 CFR 58.638 - Freezing the mix.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...false Freezing the mix. 58.638 Section...Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT...UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE...638 Freezing the mix. After the...

  9. Rupture of Cylindrical Ice Model and Tuna Fish during Freezing

    NASA Astrophysics Data System (ADS)

    Ogawa, Yutaka; Uno, Mitsuyo

    The gape and heave produced on the surface of tuna fish during freezing were confirmed by rupture of cylindrical type ice model. The results of experiment were shown as summarized below; 1) in case of restraining the progress of ice formation of model during freezing,any rupture was produced at not only slow freezing but also quick freezing. It was the same as tuna fish; 2) in case of closing surface of ice model covered perfectly by outside shell ice during slow freezing,it was not ruptured at not only ice model but also tuna fish. On the contrary it was cracked at quick freezing not only ice model but also tuna fish; 3) therefore it was confirmed that the rupture of tuna fish during freezing had been easy to produce at quick freezing.

  10. FUTURE CLIMATE SCENARIOS FOR CALIFORNIA: FREEZING ISOCLINES,

    E-print Network

    of the desert and Central Valley regions may experience expanding and novel climates, while conditions alongFUTURE CLIMATE SCENARIOS FOR CALIFORNIA: FREEZING ISOCLINES, NOVEL CLIMATES, AND CLIMATIC Climate Change Center JULY 2012 CEC-500-2012-022 Prepared for: California Energy Commission Prepared by

  11. Managing damaging freeze events in Louisiana sugarcane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exposure of sugarcane to damaging frosts occurs in approximately 25% of the sugarcane producing countries of the world, but is most frequent on the mainland of the United States, especially in the state of Louisiana. The frequent winter freezes that occur in the sugarcane areas of Louisiana have fo...

  12. Hot water can freeze faster than cold?!?

    Microsoft Academic Search

    Monwhea Jeng

    2005-01-01

    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

  13. Hiring Freeze Exception Request Form Position Title

    E-print Network

    Weston, Ken

    Hiring Freeze Exception Request Form Page 1 Position Title: Position Number: Department: Division Delivery of essential University services Courses necessary for timely graduation Position is critical to of this position and the direct impact on core and essential business operations. Explain the negative impact

  14. A Fast Hadron Freeze-out Generator

    E-print Network

    N. S. Amelin; R. Lednicky; T. A. Pocheptsov; I. P. Lokhtin; L. V. Malinina; A. M. Snigirev; Iu. A. Karpenko; Yu. M. Sinyukov

    2006-10-13

    We have developed a fast Monte Carlo procedure of hadron generation allowing one to study and analyze various observables for stable hadrons and hadron resonances produced in ultra-relativistic heavy ion collisions. Particle multiplicities are determined based on the concept of chemical freeze-out. Particles can be generated on the chemical or thermal freeze-out hypersurface represented by a parameterization or a numerical solution of relativistic hydrodynamics with given initial conditions and equation of state. Besides standard space-like sectors associated with the volume decay, the hypersurface may also include non-space-like sectors related to the emission from the surface of expanding system. For comparison with other models and experimental data we demonstrate the results based on the standard parameterizations of the hadron freeze-out hypersurface and flow velocity profile under the assumption of a common chemical and thermal freeze-out. The C++ generator code is written under the ROOT framework and is available for public use at http://uhkm.jinr.ru/.

  15. Global Annual Freezing and Thawing Indices

    NSDL National Science Digital Library

    The National Snow and Ice Data Center provide these data showing the "cumulative number of degree-days when air temperatures are below and above zero degrees Celsius." Two data files, one each for the freezing and thaw data, and a readme file are available. A Fortran program is provided in the data documentation to read the data that are in flat binary format.

  16. The SENSITIVE TO FREEZING2 Gene, Required for Freezing Tolerance in Arabidopsis thaliana, Encodes a ?-Glucosidase

    PubMed Central

    Thorlby, Glenn; Fourrier, Nicolas; Warren, Gareth

    2004-01-01

    The sensitive to freezing2-1 (sfr2-1) mutation causes freezing sensitivity in Arabidopsis thaliana. By mapping, transgenic complementation, and sequencing, sfr2-1 was revealed to be a mutation in gene At3g06510. A new knockout allele was obtained, and its identical freezing-sensitive phenotype confirmed that the SFR2 gene product is essential for freezing tolerance. Transcription of SFR2 was observed to be constitutive rather than stress inducible and was distributed throughout most aerial tissues. SFR2 encodes a protein homologous to family 1 glycosyl hydrolases (?-glycosidases), but the predicted AtSFR2 protein is divergent from all other family 1 ?-glycosidases of Arabidopsis, showing closer homology to the sequences of several ?-glycosidases from thermophilic archea and bacteria. After purification from a heterologous expression system, AtSFR2 displayed a specific hydrolytic activity against ?-d-glucosides. PMID:15258268

  17. A timescale investigation of volatile chemical retention during hydrometeor freezing: Nonrime freezing

    E-print Network

    Jacobson, Mark

    disagreement found in the studies. The theory-based analysis and methodology presented in this paper can] Collision of supercooled water with ice and subse- quent freezing to form graupel and hail is an important

  18. Exact theory of freeze out

    E-print Network

    Mirco Cannoni

    2015-03-05

    We show that the standard theory of thermal production and chemical decoupling of WIMPs is incomplete. The hypothesis that WIMPs are produced and decouple from a thermal bath implies that the rate equation the bath particles interacting with the WIMPs is an algebraic equation that constraints the actual WIMPs abundance to have a precise analytical form down to the temperature $x_\\ast=m_\\chi /T_\\ast$. The point $x_\\ast$, which coincides with the stationary point of the equation for the quantity $\\Delta= Y-Y_0$, is where the maximum departure of the WIMPs abundance $Y$ from the thermal value $Y_0$ is reached. For each mass $m_\\chi$ and total annihilation cross section $\\langle \\sigma_\\text{ann}v_\\text{r}\\rangle$, the temperature $x_\\ast$ and the actual WIMPs abundance $Y(x_\\ast)$ are exactly known. This value provides the true initial condition for the usual differential equation that have to be integrated in the interval $x\\ge x_\\ast$. The matching of the two abundances at $x_\\ast$ is continuous and differentiable. The dependence of the present relic abundance on the abundance at an intermediate temperature is an exact result. The exact theory suggests a new analytical approximation that furnishes the relic abundance accurate at the level of $1\\%-2\\%$ in the case of $S$-wave and $P$-wave scattering cross sections. We conclude the paper studying the evolution of the WIMPs chemical potential and the entropy production using methods of non equilibrium thermodynamics.

  19. VISUALIZATION OF FREEZING PROGRESSION IN TURFGRASSES USING INFRARED VIDEO THERMOGRAPHY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Freezing injury can be a significant problem in turfgrasses. Understanding how freezing develops and ramifies throughout the plant could assist in the development of improved management or screening processes for cultivar improvemen. The development of freezing injury is not well understand due pa...

  20. Foliar applied urea improves freezing protection to avocado and peach

    Microsoft Academic Search

    S. Zilkah; Z. Wiesmann; I. Klein; I. David

    1996-01-01

    The effect of foliar applied urea on freeze hardiness was evaluated under orchard and laboratory conditions. Freezing injury and senescence of avocado (Persea americana Mill.) cv. ‘Hass’ leaves in the orchard was inversely correlated to N content. Three foliar applications of 2% low-biuret urea caused a 26% nitrogen enrichment of leaves. Consequently, leaf freezing hardiness was increased and senescence retarded.

  1. STABILIZATION OF THE PHOSPHATE RATIO OF SEA WATER BY FREEZING

    E-print Network

    STABILIZATION OF THE PHOSPHATE RATIO OF SEA WATER BY FREEZING BY ALBERT W. COLLIER AND KENNETH T, Director STABILIZATION OF THE PHOSPHATE RATIO OF SEA WATER BY FREEZING By ALBERT W. COLLIER and KENNETH T_________________________________________________ 76 u #12;STABILIZATION OF THE PHOSPHATE RATIO OF SEA WATER BY FREEZING By ALBERT W. COLLIER, Fishery

  2. Interspecific analysis of xylem freezing responses in Acer and Betula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temperate woody plants have evolved two methods for coping with seasonal exposure to sub-zero temperatures. Supercooling is a freeze-avoidance strategy where cells are able to resist the freezing of intracellular water below sub-zero temperatures. Non-supercooling is a freeze-tolerance strategy wh...

  3. FREEZING-STRESS-RESPONSIVE GENES AND THEIR EXPRESSION IN BARLEY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Injury of barley plants by spring freezing is a major cause of crop loss, but most cold tolerance research has focused on cold acclimation, which confers freezing tolerance upon exposure to low nonfreezing temperatures. In order to address freezing tolerance per se, we have chosen a cold sensitive ...

  4. [Representations of causality and depression. A factorial approach to the resignation model in the depressed patient].

    PubMed

    Comiskey, F; de Bonis, M

    1988-01-01

    The present study investigates causal attributions for stressful life events within the context of Beck's cognitive theory of affective disorders and Seligman's learned helplessness model of depression. The aim was to assess the validity of the depressive attributional style proposed by Seligman, with a clinically depressed population for negative life events. This study presents a factor analysis of the causal attributions of depressed psychiatric in patients measured in relation to one negative life event per subject. The experimental procedure consisted in asking 71 ward depressed patients (51 females and 20 males) to answer 15 items along a seven point scale in order to assess the causes, consequences and control attributed. Statistical treatment using both multidimensional analyses (to describe the dimensions of causality) and univariate comparisons show: 1. The existence of a three dimensional solution, which is interpreted in terms of Seligman's reformulated helplessness model, and which confirms the notion of a "depressive attributional style". 2. A positive relationship between intensity of depression and the tendency to generalize the effects of negative life events (dimension of globality in Seligman's model and generalizability in Beck's). As this relationship is a function of the level of depression it is considered as a psychological state rather than as a personality trait. 3. Inter-sex differences with regard to the attribution of personal versus universal control, with female patients indicating more personal helplessness in relation to others. The results are discussed in relation to epidemiological data and personality theory. PMID:3391129

  5. The depressive situation

    PubMed Central

    A. Jacobs, Kerrin

    2013-01-01

    From a naturalistic perspective on mental illness, depression is often described in terms of biological dysfunctions, while a normative perspective emphasizes the lived experience of depression as a harmful condition. The paper relates a conceptual analysis of “depressive situation” to an analysis of the lived experience of depression. As such, it predominantly aims to specify depression as a harmful condition in lights of normative perspective on mental disorder, but partially refers to empirical research, i.e., naturalistic perspective on depression, to exemplarily stress on the methodological merits and limits of relating phenomenological considerations closer to empirical research. The depressive situation is further specified with an examination of the evaluative dynamics by which individuals meaningfully relate to themselves, others and the world. These evaluative dynamics emerge out of the interplay of pre-reflective and reflective processes, which are significantly altered in depression. Such alterations of the evaluative structure are inextricably intertwined with significant distortions of practical sense in depression. From a phenomenological perspective, these distortions of practical sense show in characteristic experiences of evaluative incoherence and impairments of agency. Finally, this paper focuses on an examination of “evaluative incapacity,” which has the integrative potential to capture a range of typical changes of meaningful relatedness that determine the depressive situation. PMID:23882238

  6. The depressive situation.

    PubMed

    A Jacobs, Kerrin

    2013-01-01

    From a naturalistic perspective on mental illness, depression is often described in terms of biological dysfunctions, while a normative perspective emphasizes the lived experience of depression as a harmful condition. The paper relates a conceptual analysis of "depressive situation" to an analysis of the lived experience of depression. As such, it predominantly aims to specify depression as a harmful condition in lights of normative perspective on mental disorder, but partially refers to empirical research, i.e., naturalistic perspective on depression, to exemplarily stress on the methodological merits and limits of relating phenomenological considerations closer to empirical research. The depressive situation is further specified with an examination of the evaluative dynamics by which individuals meaningfully relate to themselves, others and the world. These evaluative dynamics emerge out of the interplay of pre-reflective and reflective processes, which are significantly altered in depression. Such alterations of the evaluative structure are inextricably intertwined with significant distortions of practical sense in depression. From a phenomenological perspective, these distortions of practical sense show in characteristic experiences of evaluative incoherence and impairments of agency. Finally, this paper focuses on an examination of "evaluative incapacity," which has the integrative potential to capture a range of typical changes of meaningful relatedness that determine the depressive situation. PMID:23882238

  7. Prevention of postnatal depression.

    PubMed

    Mallikarjun, Pavan Kumar; Oyebode, Femi

    2005-09-01

    Postnatal depression is the most frequent psychiatric disorder seen after childbirth, with a prevalence rate of 10% to 15%. The women at risk need to be identified by a valid and reliable method, either using a screening instrument or an interview schedule. The preventive strategies need to have enough power to detect a clinically worthwhile effect to be considered useful in clinical practice. Many of the risk factors for developing postnatal depression are present during the pregnancy and immediate post-partum period. The risk factors for postnatal depression include depression or anxiety during pregnancy, experiencing stressful life events during pregnancy or the early puerperium, maternity blues, low levels of social support, past history of depression and poor marital adjustment. The antenatal and postnatal period provides an ideal opportunity to screen women for these risk factors. The women identified to be at risk can be identified, and preventive interventions can be implemented. Routine clinical practice can be improved to identify some of the women at risk by better communication between health professionals. There are no antenatal screening tools that have been shown to be of benefit in predicting postnatal depression. Edinburgh Postnatal Depression Scale is widely used in the postnatal period to screen for depression. The psychosocial interventions to prevent postnatal depression have not been shown to be beneficial and there is a dearth of psychopharmacological trials to make firm conclusions about their efficacy in preventing postnatal depression. Individualised psychosocial interventions aimed at the at-risk populations and initiated in the postnatal period appear to have some benefit in preventing postnatal depression. The focus of this article will be the risk factors associated with postnatal depression, screening methods and tools to identify those at risk of developing the disorder and the psychosocial, psychological and psychopharmacological interventions to prevent postnatal depression. PMID:16220736

  8. Emotion Context Insensitivity in Major Depressive Disorder Jonathan Rottenberg

    E-print Network

    Gross, James J.

    ). Normative and idiographic stimuli that elicited happy, sad, and neutral states were presented to currently responses were measured. Currently depressed individuals reported less sadness reactivity and less happiness. Positive Attenuation Hypothesis Depressed persons' low positive mood is the starting point for the positive

  9. Changes in Depression Following Divorce: A Panel Study.

    ERIC Educational Resources Information Center

    Menaghan, Elizabeth G.; Lieberman, Morton A.

    1986-01-01

    Examined changes in depressive affect in adults divorced during the four years between interviews, and compared them with people who have remained married. Those who would subsequently divorce were not significantly more depressed at the first time point than those who would remain married. Four years later, however, the newly divorced had become…

  10. Detecting depression among adolescents in Santiago, Chile: sex differences

    PubMed Central

    2013-01-01

    Background Depression among adolescents is common but most cases go undetected. Brief questionnaires offer an opportunity to identify probable cases but properly validated cut-off points are often unavailable, especially in non-western countries. Sex differences in the prevalence of depression become marked in adolescence and this needs to be accounted when establishing cut-off points. Method This study involved adolescents attending secondary state schools in Santiago, Chile. We compared the self-reported Beck Depression Inventory-II with a psychiatric interview to ascertain diagnosis. General psychometric features were estimated before establishing the criterion validity of the BDI-II. Results The BDI-II showed good psychometric properties with good internal consistency, a clear unidimensional factorial structure, and good capacity to discriminate between cases and non-cases of depression. Optimal cut-off points to establish caseness for depression were much higher for girls than boys. Sex discrepancies were primarily explained by differences in scores among those with depression rather than among those without depression. Conclusions It is essential to validate scales with the populations intended to be used with. Sex differences are often ignored when applying cut-off points, leading to substantial misclassification. Early detection of depression is essential if we think that early intervention is a clinically important goal. PMID:23617306

  11. Studying the emergence of depression and depressive symptoms during adolescence

    Microsoft Academic Search

    Jeanne Brooks-Gunn; Anne C. Petersen

    1991-01-01

    The special issue on the emergence and maintenance of depression and depressive symptoms is introduced. The special issue considers two typically separate lines of research, one focusing on severe clinical depression and another on depressive symptoms. The biological, social, and cognitive factors contributing to the emergence of depression in adolescence are highlighted in this special issue.

  12. Embodied intervention reduce depression

    NASA Astrophysics Data System (ADS)

    Song, Dong-Qing; Bi, Xin; Fu, Ying

    2011-10-01

    To investigate the difference of the selected-rate of undergraduates' depression with respect to time, gender and scales and the intervention effect of embodied exercise, 201 Undergraduates were measured with Self-Rating Depression Scale and Beck Depression Inventory (BDI).The result shows there are significant difference of the selected-rates of undergraduates' depression resulted from long-time interval rather than from short-time interval and gender. After the intervention, the selected-rates are decreased and no significant difference has been found between the embodied groups and the controlled group. Only the embodied groups maintain the better effects of the intervention in the tracking. Also the result shows that only the participants of embodied groups obtain more positive emotional experience. We conclude that there is significant difference of selected-rate of undergraduates' depression on scales, and the embodied exercise can effectively reduce undergraduate's depression.

  13. Ethiopathogenesis of Depressive Disorders

    PubMed Central

    Pasquini, M; Berardelli, I; Biondi, M

    2014-01-01

    Etiology of depressive disorders is still unknown. Several factors are involved in its pathophysiology such as neurotransmitters and neuroendocrine alterations, genetics, life events and their appraisal. Some of these components are strictly linked. Subjects with a family member affected by mood disorders are more prone to suffer from depressive disorders. It is also true that receiving feedbacks of indifference or neglect during childhood from one parent who suffer from depression may represent a factor of vulnerability. Indeed, reaction to a specific negative event may determine an increased allostasis which lead to a depressive episode. Thus, a psychological cause does not exclude a neurobiological cascade. Whereas in other cases recurrent depressive episodes appear in absence of any negative life event. This review provides a set of data regarding the current etiopathogenesis models of depression, with a particular attention to the neurobiological correlates and vulnerability factors. PMID:25614753

  14. Spacecraft Radiator Freeze Protection Using a Regenerative Heat Exchanger

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Schunk, Richard G.

    2011-01-01

    An active thermal control system architecture has been modified to include a regenerative heat exchanger (regenerator) inboard of the radiator. Rather than using a radiator bypass valve a regenerative heat exchanger is placed inboard of the radiators. A regenerator cold side bypass valve is used to set the return temperature. During operation, the regenerator bypass flow is varied, mixing cold radiator return fluid and warm regenerator outlet fluid to maintain the system setpoint. At the lowest heat load for stable operation, the bypass flow is closed off, sending all of the flow through the regenerator. This lowers the radiator inlet temperature well below the system set-point while maintaining full flow through the radiators. By using a regenerator bypass flow control to maintain system setpoint, the required minimum heat load to avoid radiator freezing can be reduced by more than half compared to a radiator bypass system.

  15. Sexual dysfunctions in depression

    Microsoft Academic Search

    Roy J. Mathew; Maxine L. Weinman

    1982-01-01

    The incidence of sexual dysfunctions in a group of 51 drug-free depressed patients and in age- and sex-matched controls was studied. Three groups of sexual dysfunction were assessed: alterations of libido, genital symptoms, and menstrual irregularities. The Beck Rating Scale for Depression, the Eysenck Personality Inventory (EPI), and the State-Trait Anxiety Inventory were completed on each participant. Depressed patients obtained

  16. Legal Ethics and Depression

    E-print Network

    Hoeflich, Michael H.

    2005-09-01

    Legal Ethi cs and Depression By Michael H. Hoeflich "no" in many, if not most cases. And herein lies the problem. Recent scientific studies have made it very clear that most forms of major depression have definite physical pathologies... that often involve progressive chemical and physical changes to the brain.5 Further, a substantial number of those individ- uals who suffer from major depression have a genetic predis- position to do so. In addition, stress, particularly stress that also...

  17. Treatment-Resistant Depression

    Microsoft Academic Search

    Jambur Ananth

    1998-01-01

    Our ability to treat depression has improved with the availability of receptor-specific and chemically diverse groups of antidepressants. Even now, most of the short-term studies indicate that about 20% of depressed patients remain resistant to treatment. Therefore, it is important to properly assess the treatment-resistant depressed (TRD) patients and to separate the truly refractory patients from those inadequately treated. Undiagnosed

  18. Post-stroke depression

    Microsoft Academic Search

    J. W. G. Tiller

    1992-01-01

    Depression is present in 25–30% of stroke patients: though associated with physical disability and loss of function, it cannot be explained simply as a response to the disability. The severity of depression correlates with proximity of the lesion to the left anterior frontal pole, while right hemisphere lesions show the reverse trend. Post-stroke depressions may last more than 7–8 months

  19. Neurobiology of Depression

    Microsoft Academic Search

    Eric J. Nestler; Michel Barrot; Ralph J. DiLeone; Amelia J. Eisch; Stephen J. Gold; Lisa M. Monteggia

    2002-01-01

    Current treatments for depression are inadequate for many individuals, and progress in understanding the neurobiology of depression is slow. Several promising hypotheses of depression and antidepressant action have been formulated recently. These hypotheses are based largely on dysregulation of the hypothalamic-pituitary-adrenal axis and hippocampus and implicate corticotropin-releasing factor, glucocorticoids, brain-derived neurotrophic factor, and CREB. Recent work has looked beyond hippocampus

  20. Cerebrovascular diseases and depression

    Microsoft Academic Search

    Himani Ghoge; Santvana Sharma; Shamash Sonawalla; Rajesh Parikh

    2003-01-01

    Cerebrovascular diseases constitute a leading health hazard. The association between stroke and depression has been recognized\\u000a for many years. Depression is the most common psychiatric disorder associated with cerebrovascular diseases, most episodes\\u000a of post-stroke depression occur in the first 2 years after a cerebrovascular accident. Studies have found an association between\\u000a lesion location, physical impairment, cognitive impairment, aphasia, and post-stroke

  1. Predictors of Persistence After a Positive Depression Screen Among Adolescents

    PubMed Central

    McCauley, Elizabeth; McCarty, Carolyn A.; Grossman, David C.; Myaing, Mon; Zhou, Chuan; Richards, Julie; Rockhill, Carol; Katon, Wayne

    2012-01-01

    OBJECTIVE: To examine predictors of depression persistence after a positive screening test to inform management protocols for screened youth. METHODS: We conducted a cohort study of 444 youth (aged 13–17 years) from a large health care delivery system. Youth with depressive symptoms, based on a 2-item depression screen, were oversampled for the baseline interview. Baseline assessments included the Patient Health Questionnaire 9-item (PHQ-9) depression screen as well as clinical factors that were hypothesized to influence depression persistence (family history of depression, functional impairment, perceived social support, anxiety symptoms, externalizing symptoms, and medical comorbidity). Logistic regression analysis was used to examine factors associated with the persistence of depression at 6 months postbaseline. RESULTS: Of 113 youth with a positive baseline screen (PHQ-9 ?11), 47% and 35% continued to be positive at 6-week and 6-month follow-up, respectively. After controlling for treatment status, only 2 factors were significantly associated with depression persistence at 6 months: baseline depressive symptom score and continuing to have a positive screen at 6 weeks. For each 1-point increase on the PHQ-9 score at baseline, youth had a 16% increased odds of continuing to be depressed at 6 months (odds ratio: 1.16, 95% confidence interval: 1.01–1.34). Youth who continued to screen positive 6 weeks later had almost 3 times the odds of being depressed at 6 months (odds ratio: 2.89, 95% confidence interval: 1.09–7.61). CONCLUSIONS: Depressive symptom severity at presentation and continued symptoms at 6 weeks postscreening are the strongest predictors of depression persistence. Patients with high depressive symptom scores and continued symptoms at 6 weeks should receive active treatment. PMID:23166342

  2. Late-life Depressive Symptoms: Prediction Models of Change

    PubMed Central

    García-Peña, Carmen; Wagner, Fernando A.; Sánchez-García, Sergio; Espinel-Bermúdez, Claudia; Juárez-Cedillo, Teresa; Pérez-Zepeda, Mario; Arango-Lopera, Victoria; Franco-Marina, Francisco; Ramírez-Aldana, Ricardo; Gallo, Joseph

    2013-01-01

    Background Depression is a well-recognised problem in the elderly. The aim of this study was to determine the factors associated with predictors of change in depressive symptoms, both in subjects with and without baseline significant depressive symptoms. Methods Longitudinal study of community-dwelling elderly people (>60 years or older), baseline evaluations, and two additional evaluations were reported. Depressive symptoms were measured using a 30-item Geriatric Depression Scale, and a score of 11 was used as cutoff point for significant depressive symptoms in order to stratify the analyses in two groups: with significant depressive symptoms and without significant depressive symptoms. Sociodemographic data, social support, anxiety, cognition, positive affect, control locus, activities of daily living, recent traumatic life events, physical activity, comorbidities, and quality of life were evaluated. Multi-level generalised estimating equation model was used to assess the impact on the trajectory of depressive symptoms. Results 7,882 subjects were assessed, with 29.42% attrition. At baseline assessment, mean age was 70.96 years, 61.15% were women. Trajectories of depressive symptoms had a decreasing trend. Stronger associations in those with significant depressive symptoms, were social support (OR .971, p<.001), chronic pain (OR 2.277, p<.001) and higher locus of control (OR .581, p<.001). In contrast for those without baseline significant depressive symptoms anxiety and a higher locus of control were the strongest associations. Conclusions New insights into late-life depression are provided, with special emphasis in differentiated factors influencing the trajectory when stratifying regarding basal status of significant depressive symptoms. Limitations The study has not included clinical evaluations and nutritional assessments PMID:23731940

  3. Hibernation physiology, freezing adaptation and extreme freeze tolerance in a northern population of the wood frog.

    PubMed

    Costanzo, Jon P; do Amaral, M Clara F; Rosendale, Andrew J; Lee, Richard E

    2013-09-15

    We investigated hibernation physiology and freeze tolerance in a population of the wood frog, Rana sylvatica, indigenous to Interior Alaska, USA, near the northernmost limit of the species' range. Winter acclimatization responses included a 233% increase in the hepatic glycogen depot that was subsidized by fat body and skeletal muscle catabolism, and a rise in plasma osmolality that reflected accrual of urea (to 106±10 ?mol ml(-1)) and an unidentified solute (to ~73 ?mol ml(-1)). In contrast, frogs from a cool-temperate population (southern Ohio, USA) amassed much less glycogen, had a lower uremia (28±5 ?mol ml(-1)) and apparently lacked the unidentified solute. Alaskan frogs survived freezing at temperatures as low as -16°C, some 10-13°C below those tolerated by southern conspecifics, and endured a 2-month bout of freezing at -4°C. The profound freeze tolerance is presumably due to their high levels of organic osmolytes and bound water, which limits ice formation. Adaptive responses to freezing (-2.5°C for 48 h) and subsequent thawing (4°C) included synthesis of the cryoprotectants urea and glucose, and dehydration of certain tissues. Alaskan frogs differed from Ohioan frogs in retaining a substantial reserve capacity for glucose synthesis, accumulating high levels of cryoprotectants in brain tissue, and remaining hyperglycemic long after thawing. The northern phenotype also incurred less stress during freezing/thawing, as indicated by limited cryohemolysis and lactate accumulation. Post-glacial colonization of high latitudes by R. sylvatica required a substantial increase in freeze tolerance that was at least partly achieved by enhancing their cryoprotectant system. PMID:23966588

  4. Social egg freezing: for better, not for worse.

    PubMed

    Mertes, Heidi; Pennings, Guido

    2011-12-01

    The possibility for healthy women to cryopreserve their oocytes in order to counter future infertility has gained momentum in recent years. However, women tend to cryopreserve oocytes at an age that is suboptimal from a clinical point of view--in their late thirties--when both oocyte quantity and quality have already considerably diminished and success rates for eventually establishing a pregnancy are thus limited. This also gives rise to ethical concerns, as the procedure is seen as giving false hope to (reproductively speaking) older women. This study evaluates which measures can be taken to turn social freezing into a procedure that is both clinically and ethically better than the current practice. The main objective of these measures is to convince those women who are most likely to (want to) reproduce at an above-average age to cryopreserve their oocytes at a time when this intervention is still likely to lead to a live birth and to discourage fertility clinics from specifically targeting women who have already surpassed the age at which good results can be expected. The possibility for healthy women to cryopreserve their oocytes in order to counter future infertility has gained momentum in recent years. However, women tend to cryopreserve oocytes at a time that is suboptimal from a clinical point of view - in their late thirties - when both oocyte quantity and quality have already considerably diminished and success rates for eventually establishing a pregnancy are thus limited. This also gives rise to ethical concerns, as the procedure is seen as giving false hope to (reproductively speaking) older women. We evaluate which measures can be taken to turn social freezing into a procedure that is both clinically and ethically better than the current practice and discern three different steps: creating public awareness; offering individualized, age-specific information and counselling; and offering predictive tests such as anti-Müllerian hormone measurements or antral follicle count. The main objective of these measures is to convince those women who are most likely to benefit from social freezing to present themselves before age 35 and to discourage fertility clinics from specifically targeting women who have already surpassed the age at which good results can be expected. PMID:22019616

  5. Anxious forms of depression.

    PubMed

    Goldberg, David P

    2014-04-01

    Previous research has described distinctive features for anxious and nonanxious forms of major depression. The concept of "mixed anxiety depression disorder" (MADD) refers to a milder degree of the anxious form of depression, since the depressive symptoms fall short of the number required for a diagnosis of major depression. It is argued that this can be thought of as a subclinical form of anxious depression, rather than a separate disorder in its own right. In view of its substantial prevalence in general medical settings, its associated disability and its public health importance, it deserves to be recognized, and seen as being continuous with the more severe forms of anxious depression. It will therefore be included in the Field Trials of the version of the ICD-11 (where ICD is the International Classification of Disease) intended for primary care. It is argued that current anxiety, depression (without anxiety), and anxious depression would cover most of the psychologically distressed patients seen in general medical settings, using a pseudodimensional system. PMID:24281827

  6. To freeze or not to: Quantum correlations under local decoherence

    E-print Network

    Titas Chanda; Amit Kumar Pal; Anindya Biswas; Aditi Sen De; Ujjwal Sen

    2014-09-07

    We provide necessary and sufficient conditions for freezing of quantum correlations as measured by the quantum discord and the quantum work deficit in the case of bipartite as well as multipartite states subjected to local noisy channels. We recognize that inhomogeneity of the magnetizations of the shared quantum states plays an important role in the freezing phenomena. We show that the frozen value of the quantum correlation and the time interval for freezing follow a complementarity relation. For states which do not exhibit freezing properties, but can be frozen effectively by suitable tuning of the state parameters, we introduce an index -- the freezing index -- to quantify the goodness of freezing. We find that the freezing index can be used to detect quantum phase transitions and discuss the corresponding scaling behavior.

  7. Implementation of a process analytical technology system in a freeze-drying process using Raman spectroscopy for in-line process monitoring.

    PubMed

    De Beer, T R M; Allesø, M; Goethals, F; Coppens, A; Heyden, Y Vander; De Diego, H Lopez; Rantanen, J; Verpoort, F; Vervaet, C; Remon, J P; Baeyens, W R G

    2007-11-01

    The aim of the present study was to propose a strategy for the implementation of a Process Analytical Technology system in freeze-drying processes. Mannitol solutions, some of them supplied with NaCl, were used as models to freeze-dry. Noninvasive and in-line Raman measurements were continuously performed during lyophilization of the solutions to monitor real time the mannitol solid state, the end points of the different process steps (freezing, primary drying, secondary drying), and physical phenomena occurring during the process. At-line near-infrared (NIR) and X-ray powder diffractometry (XRPD) measurements were done to confirm the Raman conclusions and to find out additional information. The collected spectra during the processes were analyzed using principal component analysis and multivariate curve resolution. A two-level full factorial design was used to study the significant influence of process (freezing rate) and formulation variables (concentration of mannitol, concentration of NaCl, volume of freeze-dried sample) upon freeze-drying. Raman spectroscopy was able to monitor (i) the mannitol solid state (amorphous, alpha, beta, delta, and hemihydrate), (ii) several process step end points (end of mannitol crystallization during freezing, primary drying), and (iii) physical phenomena occurring during freeze-drying (onset of ice nucleation, onset of mannitol crystallization during the freezing step, onset of ice sublimation). NIR proved to be a more sensitive tool to monitor sublimation than Raman spectroscopy, while XRPD helped to unravel the mannitol hemihydrate in the samples. The experimental design results showed that several process and formulation variables significantly influence different aspects of lyophilization and that both are interrelated. Raman spectroscopy (in-line) and NIR spectroscopy and XRPD (at-line) not only allowed the real-time monitoring of mannitol freeze-drying processes but also helped (in combination with experimental design) us to understand the process. PMID:17896825

  8. Study of Transient Nuclei near Freezing

    NASA Astrophysics Data System (ADS)

    Isobe, Masaharu; Alder, Berni

    2011-03-01

    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.

  9. Study of Transient Nuclei near Freezing

    NASA Astrophysics Data System (ADS)

    Isobe, M.; Alder, B. J.

    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.

  10. A Case of Elderly Manic-Depression with Dementia-Like Symptoms in a Manic Phase

    Microsoft Academic Search

    M. Kawai; K. Miyamoto; M. Miyamoto

    1990-01-01

    The authors present the case of an elderly manic-depressive woman who showed dementia-like symptoms only in the manic phase. The reasons why occurrence of endogenous bipolar depression (manic-depression) in the elderly is comparatively rare are considered from the point of the possibilty of latent disturbance of the brain, presbyophrenia, and pseudodementia.

  11. Depression in China: Integrating Developmental Psychopathology and Cultural-Clinical Psychology

    ERIC Educational Resources Information Center

    Ryder, Andrew G.; Sun, Jiahong; Zhu, Xiongzhao; Yao, Shuqiao; Chentsova-Dutton, Yulia E.

    2012-01-01

    With a starting point in John Abela's groundbreaking developmental psychopathology research on adolescent depression in China, we aimed to review the state of the literature on Chinese depression across the lifespan. We began with Dr. Abela's published studies relevant to depression in China and our own research with adults before turning to the…

  12. Face Emotion Processing in Depressed Children and Adolescents with and without Comorbid Conduct Disorder

    ERIC Educational Resources Information Center

    Schepman, Karen; Taylor, Eric; Collishaw, Stephan; Fombonne, Eric

    2012-01-01

    Studies of adults with depression point to characteristic neurocognitive deficits, including differences in processing facial expressions. Few studies have examined face processing in juvenile depression, or taken account of other comorbid disorders. Three groups were compared: depressed children and adolescents with conduct disorder (n = 23),…

  13. Comparative validity of three screening questionnaires for DSM-IV depressive disorders and physicians’ diagnoses

    Microsoft Academic Search

    Bernd Löwe; Robert L. Spitzer; Kerstin Gräfe; Kurt Kroenke; Andrea Quenter; Stephan Zipfel; Christine Buchholz; Steffen Witte; Wolfgang Herzog

    2004-01-01

    Background: The aim of this study was to compare the validity of the Hospital Anxiety and Depression Scale (HADS), the WHO (five) Well Being Index (WBI-5), the Patient Health Questionnaire (PHQ), and physicians’ recognition of depressive disorders, and to recommend specific cut-off points for clinical decision making. Methods: A total of 501 outpatients completed each of the three depression screening

  14. Freeze-branding to permanently mark bats

    Microsoft Academic Search

    Richard E. Sherwin; Shauna Haymond; Rebeccah Olsen

    We tested the effectiveness of freeze-branding as a permanent marking technique on 4 species of bats: Brazilian free-tailed bat (Tadarida brasiliensis), Townsend's big-eared bat (Corynorhinus townsendil), big brown bat (Eptesicus fuscus), and western small-footed myotis (Myotis ciliolabrum). Small copper branding irons (9.3 g and 15.6 g) were cooled in a mixture of dry ice and ethyl alcohol and applied to

  15. Solar desalination by freezing and distillation

    SciTech Connect

    Kvajic, G.

    1981-01-01

    Among seawater desalination processes the absorption freezing based on the thermal heat pump, the AF-VC/sup t/, appears technically and economically an attractive application of low grade (exergy) solar heat. The novel feature in this system involves a use of enlarged capacity for heat exchange between distillate and brine via latent heat of solid-liquid phase change of a suitable hydro-phobic intermediate heat transfer material. 13 refs.

  16. Freeze substitution in 3 hours or less.

    PubMed

    McDonald, K L; Webb, R I

    2011-09-01

    Freeze substitution is a process for low temperature dehydration and fixation of rapidly frozen cells that usually takes days to complete. New methods for freeze substitution have been developed that require only basic laboratory tools: a platform shaker, liquid nitrogen, a metal block with holes for cryotubes and an insulated container such as an ice bucket. With this equipment, excellent freeze substitution results can be obtained in as little as 90 min for cells of small volume such as bacteria and tissue culture cells. For cells of greater volume or that have significant diffusion barriers such as cuticles or thick cell walls, one can extend the time to 3 h or more with dry ice. The 3-h method works well for all manner of specimens, including plants and Caenorhabditis elegans as well as smaller samples. Here, we present the basics of the techniques and some results from Nicotiana leaves, C. elegans adult worms, Escherichia coli and baby hamster kidney tissue culture cells. PMID:21827481

  17. Response of New zealand mudsnails Potamopyrgus antipodarum to freezing and near freezing fluctuating water temperatures

    USGS Publications Warehouse

    Moffitt, Christine M.; James, Christopher A.

    2012-01-01

    We explored the resilience of the invasive New Zealand mudsnail Potamopyrgus antipodarum to fluctuating winter freezing and near-freezing temperature cycles in laboratory tests. Our goal was to provide data to confirm field observations of mortality and presumed mortality in stream habitats with fluctuating freezing to near-freezing temperatures. We tested individuals from 2 locations with distinctly different thermal regimes and population densities. One location had low snail densities and water temperatures with strong diel and seasonal water variation. The other location had high snail densities and nearly constant water temperatures. Groups of individuals from both locations were tested in each of 3 laboratory-created diel thermal cycles around nominal temperatures of 0, 2, or 4°C. Mortality occurred in cycles around 0°C in both populations, and little to no mortality occurred at temperatures >0°C. Individuals from both sources held in diel 0°C cycles for 72 h showed 100% mortality. Our findings support observations from published field studies that survival was limited in infested habitats subject to freezing temperatures.

  18. Fundamental technical elements of freeze-fracture/freeze-etch in biological electron microscopy.

    PubMed

    Carson, Johnny L

    2014-01-01

    Freeze-fracture/freeze-etch describes a process whereby specimens, typically biological or nanomaterial in nature, are frozen, fractured, and replicated to generate a carbon/platinum "cast" intended for examination by transmission electron microscopy. Specimens are subjected to ultrarapid freezing rates, often in the presence of cryoprotective agents to limit ice crystal formation, with subsequent fracturing of the specimen at liquid nitrogen cooled temperatures under high vacuum. The resultant fractured surface is replicated and stabilized by evaporation of carbon and platinum from an angle that confers surface three-dimensional detail to the cast. This technique has proved particularly enlightening for the investigation of cell membranes and their specializations and has contributed considerably to the understanding of cellular form to related cell function. In this report, we survey the instrument requirements and technical protocol for performing freeze-fracture, the associated nomenclature and characteristics of fracture planes, variations on the conventional procedure, and criteria for interpretation of freeze-fracture images. This technique has been widely used for ultrastructural investigation in many areas of cell biology and holds promise as an emerging imaging technique for molecular, nanotechnology, and materials science studies. PMID:25285532

  19. Viscosity Depressants for Coal Liquefaction

    NASA Technical Reports Server (NTRS)

    Kalfayan, S. H.

    1983-01-01

    Proposed process modification incorporates viscosity depressants to prevent coal from solidifying during liquefaction. Depressants reduce amount of heat needed to liquefy coal. Possible depressants are metallic soaps, such as stearate, and amides, such as stearamide and dimer acid amides.

  20. Depression During and After Pregnancy

    MedlinePLUS

    ... after pregnancy? What is the difference between "baby blues," postpartum depression, and postpartum psychosis? What should I ... is depression? Depression is more than just feeling "blue" or "down in the dumps" for a few ...

  1. Counseling Interventions with Depressed Children.

    ERIC Educational Resources Information Center

    Downing, Jerry

    1988-01-01

    Defines depression and anxiety in children and addresses assessment issues. Describes nine specific interventions within the home and school that have helped depressed children. Provides case example of depressed sixth grade boy. (ABL)

  2. Geochimica et Cosmochimica Act12Vol. 57. pp. 683-684 Copyright0 1993 Pergamon Press Ltd. Printed in U.S.A.

    E-print Network

    Bodnar, Robert J.

    the freezing point depression of H,O-NaCl solutions R. J. BODNAR Fluids Research Laboratory, Department to the freezing-point depression. The equation most often used to determine the salinity of HzO-salt inclu- sions) resulted in a cubic equation with freezing-point depression as the dependent variable and sa- linity

  3. Observations on the Freezing of Supercooled Pollen Washing Water by a New Electrodynamic Balance

    NASA Astrophysics Data System (ADS)

    Tong, Haijie; Pope, Francis D.; Kalberer, Markus

    2014-05-01

    Primary biological particles can act as efficient ice nuclei (IN) by initiating freezing events at temperatures warmer than the homogenous freezing temperature [1, 2]. For example, pollen grain particles can trigger freezing events at temperatures as warm as -5 °C in the contact freezing mode [3]. More recently pollen residues, which are released by washing pollen grains in water, were also observed to act as efficient IN in the immersion mode [4, 5]. In this study we developed a new cold electrodynamic balance (CEDB) system and investigated the freezing properties of single particles of supercooled pollen washing water (SPWW). The EDB technique allows for a contact free measurement of freezing events. The phase of the particle (liquid or frozen solid) can be distinguished via measuring the Mie scattering signal from the particle. Furthermore the size of liquid (spherical) particles can be determined. The freezing events are characterized through the loss of the regular Mie scattering signal from the levitated droplet as it changes state from liquid to a frozen solid. The statistical freezing probabilities of SPWW were obtained in the temperature range: -15 to -40 °C. Each temperature measurement point consists of the analysis of 30-100 droplets. Preliminary conclusions are that SPWW is IN active in the immersion mode. Further discussion will focus on the temperature range of the IN activity, the important variables (other than temperature) for IN activity, other likely modes of IN activity, and the implications of these results in terms of the atmospheric relevance of SPWW. This study was supported by the NERC. We acknowledge Professor Jonathan Reid and James Davis from the University of Bristol for providing information of the design of the warm EDB system. References: [1] Möhler, O., et al. (2007) Biogeosciences, 4, 1059-1071. [2] Prenni, A. J., et al. (2009) Nat. Geosci., 2, 401-404. [3] Diehl, K., et al. (2002) Atmos. Res., 61, 125-133. [4] Pummer, B. G., et al. (2012) Atmos. Chem. Phys., 12, 2541-2550. [5] Augustin, S., et al. (2013) Atmos. Chem. Phys., 13, 10989-11003.

  4. Pour-depressant additives for diesel fuels

    Microsoft Academic Search

    S. R. Lebedev; R. M. Berezina; Ya. B. Chertkov

    1975-01-01

    1.Straight-chain alkanes, when added to diesel fuel in amounts of 5% or more, harm the low-temperature characteristics of the fuel. The presence of these hydrocarbons will produce sharp increases in the cloud point, filterability temperature, and solid point of diesel fuels, and it is found that these three temperatures tend to converge when the n-alkanes are present.2.The most effective pour-depressant

  5. Sex differences in depression

    Microsoft Academic Search

    Lenore S. Radloff

    1975-01-01

    The role of housewife has been hypothesized as the source of excess mental illness among married women as compared with married men. The present study found both housewives and working wives significantly more depressed than working husbands. Although working wives report that they do more housework than husbands, this factor was not significantly related to depression for either wives or

  6. Pharmacoendocrinology of major depression

    Microsoft Academic Search

    Robert T. Rubin

    1989-01-01

    Major depressives often have abnormalities in the secretion patterns of their anterior pituitary hormones and target endocrine gland hormones. There are changes in both basal hormone secretion and the responses of these hormones to perturbation tests. Considerable work has been done attempting to develop a clinical application for some of these changes as biological state markers of endogenous depression. Prominent

  7. The Depression Coping Questionnaire.

    ERIC Educational Resources Information Center

    Kleinke, Chris L.

    College students (N=396), chronic pain patients (N=319), and schizophrenic veterans (N=43) completed the Depression Coping Questionnaire (DCQ) and the Beck Depression Inventory (BDI). Factor analysis of the DCQ identified eleven coping responses: social support, problem solving, self-blame/escape, aggression, indulgence, activities, medication,…

  8. Depression in the Elderly

    Microsoft Academic Search

    MICHAEL SERBY; MI YU

    Depression in the elderly population is a major public health problem. It has a high prevalence, is fre- quently co-morbid with medical illnesses, impacts negatively on quality of life, increases the number of visits to different medical services, and carries a high risk of suicide, especially in men. Imaging studies have increased our understanding of the biological mechanisms of depression

  9. Postpartum Depression: An Overview.

    ERIC Educational Resources Information Center

    Albright, Angela

    1993-01-01

    Occurring in about 12 percent of postpartum women, postpartum depression has been focus of considerable research. Variables that have been correlated with postpartum depression range from biological causes, to lack of social support, to relationship with husband, to attributional styles, to psychodynamic explanations. There is need for more…

  10. Activities on Facebook Reveal the Depressive State of Users

    PubMed Central

    Kwak, Jinah

    2013-01-01

    Background As online social media have become prominent, much effort has been spent on identifying users with depressive symptoms in order to aim at early diagnosis, treatment, and even prevention by using various online social media. In this paper, we focused on Facebook to discern any correlations between the platform’s features and users’ depressive symptoms. This work may be helpful in trying to reach and detect large numbers of depressed individuals more easily. Objective Our goal was to develop a Web application and identify depressive symptom–related features from users of Facebook, a popular social networking platform. Methods 55 Facebook users (male=40, female=15, mean age 24.43, SD 3.90) were recruited through advertisement fliers distributed to students in a large university in Korea. Using EmotionDiary, the Facebook application we developed, we evaluated depressive symptoms using the Center for Epidemiological Studies-Depression (CES-D) scale. We also provided tips and facts about depression to participants and measured their responses using EmotionDiary. To identify the Facebook features related to depression, correlation analyses were performed between CES-D and participants’ responses to tips and facts or Facebook social features. Last, we interviewed depressed participants (CES-D?25) to assess their depressive symptoms by a psychiatrist. Results Facebook activities had predictive power in distinguishing depressed and nondepressed individuals. Participants’ response to tips and facts, which can be explained by the number of app tips viewed and app points, had a positive correlation (P=.04 for both cases), whereas the number of friends and location tags had a negative correlation with the CES-D scale (P=.08 and P=.045 respectively). Furthermore, in finding group differences in Facebook social activities, app tips viewed and app points resulted in significant differences (P=.01 and P=.03 respectively) between probably depressed and nondepressed individuals. Conclusions Our results using EmotionDiary demonstrated that the more depressed one is, the more one will read tips and facts about depression. We also confirmed depressed individuals had significantly fewer interactions with others (eg, decreased number of friends and location tagging). Our app, EmotionDiary, can successfully evaluate depressive symptoms as well as provide useful tips and facts to users. These results open the door for examining Facebook activities to identify depressed individuals. We aim to conduct the experiment in multiple cultures as well. PMID:24084314

  11. Impurity and thermal modelling of SPRT fixed-points

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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.

  12. Numerical analysis of the heat transfer associated with freezing\\/solidifying phase changes for a pipeline filled with crude oil in soil saturated with water during pipeline shutdown in winter

    Microsoft Academic Search

    Tao Lu; Kui-sheng Wang

    2008-01-01

    A flow and heat transfer model for a crude oil pipeline buried in soil saturated with water during shutdown, where ambient temperature is below the freezing point of water, has been established. Phase changes involving water freezing in the soil and crude oil solidifying in the pipeline and the influence of initial temperature and flow field were included in the

  13. Depression and atherosclerosis.

    PubMed

    Saleptsis, V G; Labropoulos, N; Halaris, A; Angelopoulos, N V; Giannoukas, A D

    2011-04-01

    The aim of this paper was to examine the interaction between depression and atherosclerosis through a systematic review. A Medline search was performed from 1966 through 2009 using relevant terms such as depression, epidemiology and atherosclerosis. This was supplemented by a thorough manual search using bibliographies of reviews and full articles. The papers were divided and analyzed separately for each vascular bed. Depression is diagnosed usually before atherosclerosis becomes obvious. The contribution of depression in the development of atherosclerosis emerges from various mechanisms, including lack of physical activity, that exist in this illness. Controversies about the etiology and pathogenesis exist. These interactions of all elements and the importance of each one have not been investigated adequately. Repeated objective measurements for atherosclerosis are lacking. There is an association between depression and atherosclerosis, but the strength of this relationship has to be determined. Prospective studies are needed to determine the early and long term effects of their interaction. PMID:21427645

  14. Risk factors for depression in patients undergoing hematopoietic cell transplantation.

    PubMed

    Artherholt, Samantha B; Hong, Fangxin; Berry, Donna L; Fann, Jesse R

    2014-07-01

    Despite the prevalence and known adverse impacts of depression after hematopoietic cell transplantation (HCT), little is known about the trajectory of depression occurring after HCT, or which pretransplantation risk factors might help predict new or worsening post-HCT depression. This secondary analysis evaluated the relationships between pre-HCT patient-reported outcomes and demographic characteristics and post-HCT depression. A total of 228 adult HCT patients were evaluated pre-HCT (T1) and again at 6 to 7 weeks post-HCT (T2), using touch-screen computers in the transplantation clinic during participation in a larger trial. Measures evaluated included the Symptom Distress Scale, the EORTC QLQ-C30 for quality of life, a single-item pain intensity question, and the Patient Health Questionnaire 9 for measurement of depression. At T1, rates of depression were quite low, with only 6% of participants reporting moderate or higher depression. At T2, however, the prevalence of moderate or higher depression was 31%. We observed a strong linear relationship in PHQ-9 scores between T1 and T2 (P < .0001). Depression score at T1 was a significant predictor of depression score at T2 (P = .03), as was poorer emotional function at T1 (P < .01). Our results indicate that post-HCT depression is common, even in patients with a low pre-HCT depression score. Frequent screening for symptoms of depression at critical time points, including 6 to 7 weeks post-HCT, are needed in this population, followed by referrals to supportive care as appropriate. PMID:24650679

  15. Existence of a mannitol hydrate during freeze-drying and practical implications.

    PubMed

    Yu, L; Milton, N; Groleau, E G; Mishra, D S; Vansickle, R E

    1999-02-01

    We report thermal and crystallographic evidence for a previously unknown mannitol hydrate that is formed in the process of freeze-drying. The mannitol hydrate was produced by freeze-drying pure mannitol solutions (1-4% w/v) using the following cycle: (1) equilibration at -5 degreesC for 1 h; (2) freezing at -40 degreesC; (3) primary drying at -10 degreesC for 15 h; and (4) secondary drying at 10 degreesC for 2 h and then 25 degreesC for 5 h. This crystal form was also observed upon freeze-drying in the presence of sorbitol (1% w/v). The mannitol hydrate showed a distinct X-ray powder diffraction pattern, low melting point, and steplike desolvation behavior that is characteristic of crystalline hydrates. The mannitol hydrate was found to be metastable, converting to anhydrous polymorphs of mannitol upon heating and exposure to moisture. The amount of the mannitol hydrate varied significantly from vial to vial, even within the same batch. The formation of mannitol hydrate has several potential consequences: (1) reduced drying rate; (2) redistribution of the residual hydrate water during accelerated storage to the amorphous drug; and (3) vial-to-vial variation of the moisture level. PMID:9950638

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

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

  17. An electrochemical in situ study of freezing and thawing of ionic liquids in carbon nanopores.

    PubMed

    Weingarth, Daniel; Drumm, Robert; Foelske-Schmitz, Annette; Kötz, Rüdiger; Presser, Volker

    2014-10-21

    Room temperature ionic liquids (RTILs) are an emerging class of electrolytes enabling high cell voltages and, in return, high energy density of advanced supercapacitors. Yet, the low temperature behavior, including freezing and thawing, is little understood when ions are confined in the narrow space of nanopores. This study shows that RTILs may show a tremendously different thermal behavior when comparing bulk with nanoconfined properties as a result of the increased surface energy of carbon pore walls. In particular, a continuous increase in viscosity is accompanied by slowed-down charge-discharge kinetics as seen with in situ electrochemical characterization. Freezing reversibly collapses the energy storage ability and thawing fully restores the initial energy density of the material. For the first time, a different thermal behavior in positively and negatively polarized electrodes is demonstrated. This leads to different freezing and melting points in the two electrodes. Compared to bulk, RTILs in the confinement of electrically charged nanopores show a high affinity for supercooling; that is, the electrode may freeze during heating. PMID:25201074

  18. Freeze-fracture study of the bloodstream form of Trypanosoma brucei gambiense.

    PubMed

    Yoshikawa, H; Furuki, J; Takahashi, Y; Morioka, H; Yoshida, Y

    1990-01-01

    The ultrastructure of Trypanosoma brucei gambiense was investigated by the freeze-fracture method. Three different regions of the continuous plasma membrane; cell body proper, flagellar pocket, and flagellum were compared in density and distribution of the intramembranous particles (IMP's). The IMP-density was highest in the flagellar pocket membrane and lowest in flagellum. Intra membranous particles of the cell body membrane were distributed uniformly on both the protoplasmic (P) and exoplasmic (E) faces. On the P face of the flagellar membrane, a single row of IMP-clusters was seen along the juncture of the flagellum to the cell body. Since the spacing of the IMP-clusters was almost equal to the spacing of the paired rivet structures observed in thin section, these clusters likely are related to the junction of flagellum and cell body. At the neck of the flagellar pocket, several linear arrays of IMP's were found on the P face of the flagellar membrane, while on the E face rows of depressions were seen. At the flagellar base, the clusters of IMP's were only seen on the P face. On the flagellar pocket membrane, particle-rich depressions and linear particle arrays were also found on the P face, while on the E face such special particle arrangements were not recognized. These particle-rich depressions may correspond to the sites of pinocytosis of the bloodstream forms which have been demonstrated in thin sections. PMID:2304029

  19. Relationship of Beck Depression Inventory factors to depression among adolescents

    Microsoft Academic Search

    David S Bennett; Paul J Ambrosini; Michael Bianchi; Diana Barnett; Claudia Metz; Harris Rabinovich

    1997-01-01

    Beck Depression Inventory (BDI) scores of 328 adolescents referred to a depression clinic were factor analyzed to test the discriminant validity of each factor. Three of the four factors (Negative Self Attitude, Performance Difficulty, and Somatic Symptoms) discriminated depressed adolescents from those with a behavior disorder or no diagnosis; the Negative Self Attitude and Performance Difficulty factors also discriminated depressed

  20. Immersion freezing of birch pollen washing water

    NASA Astrophysics Data System (ADS)

    Augustin, Stefanie; Hartmann, Susan; Pummer, Bernhard; Grothe, Hinrich; Niedermeier, Dennis; Clauss, Tina; Voigtländer, Jens; Tomsche, Laura; Wex, Heike; Stratmann, Frank

    2013-04-01

    Up to now, the importance of pollen for atmospheric ice nucleation was considered to be minor, as they are too large to stay in the atmosphere for a long time. But as recent investigations have shown, not the pollen grains themselves are responsible for freezing, but easily suspendable macromolecules on their surfaces (Pummer et al., 2012). Due to the bursting of pollen grains these ice nucleating active (INA) macromolecules could be numerous in the atmosphere. 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, Hartmann et al., 2011). For this, washing water of two different birch pollen samples with different origin (Northern birch and Southern birch) were used. Immersion freezing of droplets generated from the pollen washing water was observed at temperatures higher than -20 °C for both samples. The main difference between the Northern and the Southern birch pollen was the temperature dependence of the immersion freezing process. Our results suggest that the ice nucleating potential of the Southern birch is controlled by a single type of INA macromolecule, while the Northern birch pollen seem to feature two distinctively different types of INA macromolecules. We determined the heterogeneous nucleation rates for both INA macromolecule types and thereby consistently describe the ice nucleation behavior of both, the Southern and the Northern birch pollen washing water. Furthermore we will suggest a theoretical framework for describing e.g. single INA macromolecule related ice nucleation in atmospheric models. References: Pummer, B. G., Bauer, H., Bernardi, J., Bleicher, S. and Grothe, H.: Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen. Atmos. Chem. Phys., 12, 2541-2550, doi:10.5194/acp-12-2541-2012, 2012. Hartmann, S., Niedermeier, D., Voigtländer, J., Clauss, T., Shaw, R. A., Wex, H., Kiselev, A., and Stratmann, F.: Homogeneous and heterogeneous ice nucleation at LACIS: operating principle and theoretical studies, Atmos. Chem. Phys., 11, 1753-1767, doi:10.5194/acp-11-1753-2011, 2011.

  1. Management of Postpartum Depression

    PubMed Central

    Guille, Constance; Newman, Roger; Fryml, Leah D.; Lifton, Clay K.; Epperson, C. Neill

    2013-01-01

    Postpartum depression, now termed peripartum depression by the DSM-V, is one of the most common complications in the postpartum period and has potentially significant negative consequences for mothers and their families. This article highlights common clinical challenges in the treatment of peripartum depression and reviews the evidence for currently available treatment options. Psychotherapy is the first-line treatment options for women with mild-to-moderate peripartum depression. Antidepressant medication in combination with therapy is recommended for women with moderate-to-severe depression. While pooled case reports and small controlled studies have demonstrated undetectable infant serum levels and no short-term adverse events in infants of mothers breastfeeding while taking sertraline (Zoloft) and paroxetine (Paxil), further research is needed including larger samples and long-term follow-up of infants exposed to antidepressants via breastfeeding with control for maternal depression. Pharmacological treatment recommendations in women who are lactating must include discussion with the patient regarding the benefits of breastfeeding, risks of antidepressant use during lactation and risks of untreated illness. There is a growing evidence base for non-pharmacological interventions including repetitive Transcranial Magnetic Stimulation (rTMS) which may offer an attractive option for women who wish to continue to breastfeed and are concerned about exposure of medication to their infant. Among severe cases of peripartum depression with psychosis referral to a psychiatrist or psychiatric APRN is warranted. Suicidal or homicidal ideation with a desire, intent or plan to harm oneself or anyone one else, including the infant, is a psychiatric emergency, and an evaluation by a mental health professional should be conducted immediately. Peripartum depression treatment research is limited by small samples sizes and few controlled studies. Much work is still needed to better understand which treatments women prefer and are the most effective in ameliorating the symptoms and disease burden associated with peripartum depression. PMID:24131708

  2. Arabidopsis ESK1 encodes a novel regulator of freezing tolerance

    Microsoft Academic Search

    Zhanguo Xin; Ajin Mandaokar; Junping Chen; Robert L. Last; John Browse

    2007-01-01

    Summary The eskimo1 (esk1) mutation of Arabidopsis resulted in a 5.5? C improvement in freezing tolerance in the absence of cold acclimation. Here we show that the increase in freezing tolerance is not associated with any increase in the ability to survive drought or salt stresses, which are similar to freezing in their induction of cellular dehydration. Genome-wide comparisons of

  3. [Post-stroke depression].

    PubMed

    Schulte-Altedorneburg, Mónika; Bereczki, Dániel

    2014-08-24

    Cerebrovascular diseases are associated with a high incidence of psychiatric disorders. Depressive illness after stroke has been extensively investigated during the last three decades. Post-stroke depression is estimated to occur in 30-35% of the patients during the first year after stroke. Numerous studies have given information on its prevalence, pathogenesis, clinical course, treatment and prevention. Despite the high level of comorbidity, depressive symptoms appear to remain frequently unrecognized and untreated. This has a negative effect on the rehabilitation, quality of live, cognitive function and mortality of stroke patients. PMID:25131526

  4. Effects of Electric and Magnetic Field on Freezing and Possible Relevance in Freeze Drying

    Microsoft Academic Search

    M. W. Woo; A. S. Mujumdar

    2010-01-01

    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

  5. Long-Term Preservation of Mouse Spermatozoa after Freeze-Drying and Freezing Without Cryoprotection1

    Microsoft Academic Search

    Monika A. Ward; Takehito Kaneko; Hirokazu Kusakabe; John D. Biggers; David G. Whittingham; Ryuzo Yanagimachi

    The widespread production of mice with transgenes, disrupt- ed genes and mutant genes, has strained the resources available for maintaining these mouse lines as live populations, and de- pendable methods for gamete and embryo preservation in these lines are needed. Here we report the results of intracytoplasmic sperm injection (ICSI) with spermatozoa freeze-dried or frozen without a cryoprotectant after storage

  6. Optical coherence tomography-based freeze-drying microscopy

    PubMed Central

    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

    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. PMID:22254168

  7. Anoxia tolerance and freeze tolerance in hatchling turtles.

    PubMed

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

    2005-04-01

    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

  8. Experimental quantification of contact freezing in an electrodynamic balance

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

    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.

  9. Experimental quantification of contact freezing in an electrodynamic balance

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    Heterogeneous nucleation of ice in a supercooled water droplet induced by an 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 allowing to determine the temperature dependent ice nucleation probability of size selected aerosol particles. The method uses supercooled charged water droplets suspended 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 time scale of our experiment.

  10. Reversible Photoinhibition in Antarctic Moss during Freezing and Thawing.

    PubMed Central

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

    1995-01-01

    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

  11. Design of a blood-freezing system for leukemia research

    NASA Technical Reports Server (NTRS)

    Williams, T. E.; Cygnarowicz, T. A.

    1978-01-01

    Leukemia research involves the use of cryogenic freezing and storage equipment. In a program being carried out at the National Cancer Institute (NCI), bone marrow (white blood cells) was frozen using a standard cryogenic biological freezer. With this system, it is difficult to maintain the desired rate of freezing and repeatability from sample to sample. A freezing system was developed that satisfies the requirements for a repeatable, constant freezing rate. The system was delivered to NIC and is now operational. This report describes the design of the major subsystems, the analyses, the operating procedure, and final system test results.

  12. Depression, Dementia, and Social Supports.

    ERIC Educational Resources Information Center

    Esser, Sally R.; Vitaliano, Peter P.

    1988-01-01

    Reviews recent literature on the relationships among dementia, depression, and social support, emphasizing the diagnostic differentiation of dementia and depression, and the role of these three entities in elderly with cognitive impairment. Discusses dementia-like symptoms arising in depression and the coexistence of dementia and depression.…

  13. The concept of major depression

    Microsoft Academic Search

    Michael Philipp; Wolfgang Maier; Cynthia D. Delmo

    1991-01-01

    Summary The comparative validity of six operational diagnoses of major depression was evaluated in 600 psychiatric inpatients using the independently assessed clinical ICD-9 diagnoses as a yardstick. Agreement with, and positive predictive value for the ICD-9 categories of pure (endogeneous and psychogenic) depression served as validation criteria; sensitivity of major depression diagnoses for detecting ICD-9 bipolar depressions was additionally used

  14. A new approach for freezing of aqueous solutions under active control of the nucleation temperature.

    PubMed

    Petersen, Ansgar; Schneider, Hendrik; Rau, Guenter; Glasmacher, Birgit

    2006-10-01

    An experimental setup for controlled freezing of aqueous solutions is introduced. The special feature is a mechanism to actively control the nucleation temperature via electrofreezing: an ice nucleus generated at a platinum electrode by the application of an electric high voltage pulse initiates the crystallization of the sample. Using electrofreezing, the nucleation temperature in pure water can be precisely adjusted to a desired value over the whole temperature range between a maximum temperature Tn(max) close to the melting point and the temperature of spontaneous nucleation. However, the presence of additives can inhibit the nucleus formation. The influence of hydroxyethylstarch (HES), glucose, glycerol, additives commonly used in cryobiology, and NaCl on Tn(max) were investigated. While the decrease showed to be moderate for the non-ionic additives, the hindrance of nucleation by ionic NaCl makes the direct application of electrofreezing in solutions with physiological salt concentrations impossible. Therefore, in the multi-sample freezing device presented in this paper, the ice nucleus is produced in a separate volume of pure water inside an electrode cap. This way, the nucleus formation becomes independent of the sample composition. Using electrofreezing rather than conventional seeding methods allows automated freezing of many samples under equal conditions. Experiments performed with model solutions show the reliability and repeatability of this method to start crystallization in the test samples at different specified temperatures. The setup was designed to freeze samples of small volume for basic investigations in the field of cryopreservation and freeze-drying, but the mode of operation might be interesting for many other applications where a controlled nucleation of aqueous solutions is of importance. PMID:16887112

  15. Ultrastructure of the echinoderm cuticle after fast-freezing/freeze substitution and conventional chemical fixations.

    PubMed

    Ameye, L; Hermann, R; DuBois, P; Flammang, P

    2000-03-15

    The cuticles of the pedicellaria primordia in the sea urchin Paracentrotus lividus and of the tube foot disk in the sea star Asterias rubens were preserved by different methods, viz., glutaraldehyde fixation followed by osmium tetroxide postfixation, glutaraldehyde-ruthenium red fixation followed by osmium tetroxide-ruthenium red postfixation, and two fast freezing / freeze substitution methods (FF/FS). The gross ultrastructure of the cuticle as well as the influence of the preservation method on this ultrastructure were identical for the two tissues studied. The cuticle ultrastructure was poorly preserved after glutaraldehyde fixation / osmium tetroxide postfixation. Its preservation was improved after ruthenium red was added in the fixative and postfixative, but the best preservation was consistently achieved using FF/FS. Both low-pressure freezing (plunge freezing) and high-pressure freezing were tested, the latter giving seemingly better results. With these methods, the cuticle appeared to be composed of a proximal lower cuticle, an intermediate upper cuticle, and a distal fuzzy coat. In particular, cryoimmobilization methods emphasized or revealed the occurrence of a well-developed fibrillar lower cuticle in the pedicellaria, the complexity of the upper cuticle which consisted of several zones, and the importance of the usually poorly preserved fuzzy coat that is actually the thickest layer of the cuticle. These observations bring new insights on the functions of the cuticle, and particularly of the fuzzy coat. According to its preservation characteristics, the fuzzy coat presumably consists mostly of proteoglycans. This composition could give it shock absorption and antifouling properties. Furthermore, its important thickness also implies that molecules detected by the short sensory cilia must diffuse through and could be selected by the fuzzy coat. PMID:10738319

  16. Freezing efficiency of Silver Iodide, ATD and Kaolinite in the contact freezing mode

    NASA Astrophysics Data System (ADS)

    Nagare, Baban; Marcolli, Claudia; Stetzer, Olaf; Lohmann, Ulrike

    2014-05-01

    The importance of heterogeneous ice nucleation via contact freezing is one of the open questions in the atmospheric science community. In our laboratory, we built the Collision Nucleation CHamber (CLINCH) (Ladino et al. 2011) in which falling cloud droplets can collide with aerosol particles. In this study, contact freezing experiments are conducted to investigate the ice nucleation ability of silver iodide (AgI), kaolinite and Arizona Test Dust (ATD). Silver iodide has been known for its ice nucleation ability since 1940s (Vonnegut 1947) while kaolinite is a clay mineral and known to be a moderate ice nucleus. ATD is a commercial dust sample used by many groups to compare different setups. In CLINCH, size selected aerosol particles collide with water droplets of 80 µm diameter. With the extension in chamber length it is possible to vary the interaction time of ice nuclei and the droplets. Our experiments are performed between -10 to -36 ºC for various concentrations of ice nuclei and different interaction times. The frozen fraction of the droplets is determined using the custom-made depolarization detector IODE (Nicolet et al., 2010). Depolarization of linearly polarized incident laser light is used to determine the ratio of frozen droplets to all droplets. Frozen fractions of the three particle types with different residence times from CLINCH will be presented in this study. The number of collisions between a single droplet and several aerosol particles can be calculated by accounting for the theoretical collision efficiency at the experimental conditions in order to obtain the freezing efficiency (frozen fraction/number of collisions). Nucleation efficiency is compared with other contact freezing studies and with immersion freezing

  17. To Freeze or Not to Freeze? An Evolutionary Perspective on the Cold?Hardiness Strategies of Overwintering Ectotherms

    Microsoft Academic Search

    Yann Voituron; Nicolas Mouquet; Claire de Mazancourt; Jean Clobert

    2002-01-01

    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

  18. Freeze Extrusion Fabrication In a freeze extrusion fabrication process a ceramic slurry is extruded through a syringe. A stepper

    E-print Network

    Landers, Robert G.

    Freeze Extrusion Fabrication QUESTION 1 In a freeze extrusion fabrication process a ceramic slurry to determine an average mass flow rate. For the data in Table 1, Use the least squares method to determine 2.167 19 3.100 20 3.017 21 3.183 22 3.067 #12;Freeze Extrusion Fabrication 23 3.317 24 4.017 25 4

  19. Freeze–thaw cycle amplitude and freezing rate effects on extractable nitrogen in a temperate old field soil

    Microsoft Academic Search

    Amy C. Elliott; Hugh A. L. Henry

    2009-01-01

    Freeze–thaw cycles can promote soil N losses as a result of microbial and root cell lysis; however, minimal freeze–thaw effects\\u000a have typically been observed in studies that have imposed moderate temperature cycles. We conducted laboratory incubations\\u000a on surface soil (top 3 cm) collected in a temperate old field from late fall through mid-winter to examine how variation in\\u000a freeze–thaw amplitude, number,

  20. NOL-ring based evaluation of freeze and freeze–thaw exposure effects on FRP composite column wrap systems

    Microsoft Academic Search

    S Zhang; V. M Karbhari; D Reynaud

    2001-01-01

    Four different fiber reinforced polymer (FRP) composite column wrap systems are evaluated for durability after exposure to freeze (?15°F) and freeze–thaw conditions. Response and failure mechanisms are characterized through Naval Ordinance Laboratory-ring burst tests, short-beam-shear tests, dynamic mechanical thermal analysis and microscopy. It is shown that freeze–thaw exposure after salt soak can have a significant detrimental effect and results in

  1. Effect of repeated freeze-thaw cycles on geographically different populations of the freeze-tolerant worm Enchytraeus albidus (Oligochaeta).

    PubMed

    Fisker, Karina Vincents; Holmstrup, Martin; Malte, Hans; Overgaard, Johannes

    2014-11-01

    Freeze-tolerant organisms survive internal ice formation; however, the adaptations to repeated freeze-thaw cycles are often not well investigated. Here we report how three geographically different populations of Enchytraeus albidus (Germany, Iceland and Svalbard) respond to three temperature treatments - constant thawed (0°C), constant freezing (-5°C) and fluctuating temperature (0 to -5°C) - over a period of 42 days. Survival varied between treatments and populations such that enchytraeids from arctic locations had a higher survival following prolonged freeze periods compared with temperate populations. However, enchytraeids from temperate locations had the same survival rate as arctic populations when exposed to repeated freeze-thaw events. Across all populations, metabolic rate decreased markedly in frozen animals (-5°C) compared with thawed controls (0°C). This decrease is likely due to the lower temperature of frozen animals, but also to the transition to the frozen state per se. Animals exposed to repeated freeze-thaw events had an intermediate metabolic rate and freeze-thaw events were not associated with pronounced excess energetic costs. Overwintering under either condition was not associated with a decrease in lipid content; however, during exposure to constant freezing and repeated freeze-thaw events there was a noticeable decrease in carbohydrate stores over time. Thus, animals exposed to constant freezing showed a decrease in glycogen stores, while both glucose and glycogen content decreased over time when the organisms were exposed to repeated freezing. The results therefore suggest that carbohydrate resources are important as a fuel for E. albidus during freezing whereas lipid resources are of marginal importance. PMID:25214492

  2. A Holistic Description of Immersion Freezing of Water and Aqueous Solution Droplets Using a Water Activity Based Model

    NASA Astrophysics Data System (ADS)

    Knopf, D. A.; Alpert, P. A.

    2013-12-01

    Immersion freezing of water and aqueous solutions by particles acting as ice nuclei (IN) is a common process of heterogeneous ice nucleation in the atmosphere where it results in the glaciation of mixed-phase and cirrus clouds. Using a variety of IN types suspended in various aqueous solutions and pure water, we find that immersion freezing temperatures and kinetics can be described solely by temperature, T, and solution water activity, aw, which is the ratio of the vapor pressure of the solution and the saturation water vapor pressure under the same conditions and, in equilibrium, is equivalent to relative humidity (RH). This allows the freezing point and corresponding heterogeneous ice nucleation rate coefficient, Jhet, to be uniquely expressed by T and aw, a result termed the aw based immersion freezing model (ABIFM). This method is independent of the nature of the solute, applicable for pure water droplet freezing which is significant for mixed-phase cloud formation, and accounts for several varying parameters, including cooling rate and IN surface area, while providing a holistic description of immersion freezing capable of predicting of freezing temperatures, Jhet, frozen fractions, ice particle production rates and numbers. Our findings are based on experimental freezing data collected for various IN surface areas and cooling rates of droplets containing marine biogenic material, two soil humic acids, four mineral dusts, and one organic monolayer acting as IN. For all investigated IN types we demonstrate that droplet freezing temperatures increase as IN surface area increases. Similarly, droplet freezing temperatures increase as the cooling rate decreases. The experimental data implicitly questions the common notion that one active site initiates the formation of an ice embryo leading to the crystallization of the aqueous phase. The log10(Jhet) values for the various IN types derived exclusively by T and aw, provide a complete description of the heterogeneous ice nucleation kinetics. Thus, the ABIFM can be applied over the entire range of T, RH, total IN surface area, and cloud activation timescales typical of atmospheric conditions. Lastly, we demonstrate that ABIFM can be used to derive frozen fractions of droplets and ice particle production for atmospheric models of cirrus and mixed phase cloud conditions.

  3. Time-dependent freezing rate parcel model

    NASA Astrophysics Data System (ADS)

    Vali, G.; Snider, J. R.

    2015-02-01

    The time-dependent freezing rate (TDFR) model here described represents the formation of ice particles by immersion freezing within an air parcel. The air parcel trajectory follows an adiabatic ascent and includes a period in time when the parcel remains stationary at the top of its ascent. The description of the ice nucleating particles (INPs) in the air parcel is taken from laboratory experiments with cloud and precipitation samples and is assumed to represent the INP content of the cloud droplets in the parcel. Time dependence is included to account for variations in updraft velocity and for the continued formation of ice particles under isothermal conditions. The magnitudes of these factors are assessed on the basis of laboratory measurements. Results show that both factors give rise to three-fold variations in ice concentration for a realistic range of the input parameters. Refinements of the parameters specifying time dependence and INP concentrations are needed to make the results more specific to different atmospheric aerosol types. The simple model framework described in this paper can be adapted to more elaborate cloud models. The results here presented can help guide decisions on whether to include a time-dependent ice nucleation scheme or a simpler singular description in models.

  4. Fundamental Boiling and RP-1 Freezing Experiments

    NASA Technical Reports Server (NTRS)

    Goode, Brian; Turner, Larry D. (Technical Monitor)

    2001-01-01

    This paper describes results from experiments performed to help understand certain aspects of the MC-1 engine prestart thermal conditioning procedure. The procedure was constrained by the fact that the engine must chill long enough to get quality LOX at the LOX pump inlet but must be short enough to prevent freezing of RP-1 in the fuel pump. A chill test of an MC-1 LOX impeller was performed in LN2 to obtain data on film boiling, transition boiling and impeller temperature histories. The transition boiling data was important to the chill time so a subsequent experiment was performed chilling simple steel plates in LOX to obtain similar data for LOX. To address the fuel freezing concern, two experiments were performed. First, fuel was frozen in a tray and its physical characteristics were observed and temperatures of the fuel were measured. The result was physical characteristics as a function of temperature. Second was an attempt to measure the frozen thickness of RP-1 on a cold wall submerged in warm RP-1 and to develop a method for calculating that thickness for other conditions.

  5. Depression after Stroke

    MedlinePLUS

    ... Resources What Treatments Should You Discuss with Your Healthcare Team? What Are the Signs and Symptoms of Depression? ... top What Treatments Should You Discuss with Your Healthcare Team? Get help from your healthcare team quickly. The ...

  6. Learning about depression

    MedlinePLUS

    Talk therapy and counseling can help many people with depression. It also helps you learn ways to deal ... and thoughts. There are many different types of talk therapy. Effective treatment often combines: Talk therapy Lifestyle changes ...

  7. Depression in the Workplace

    MedlinePLUS

    ... as heart disease or AIDS to the US economy, costing over $51 billion in absenteeism from work ... on treatment for heart disease iv . The annual economic cost of depression in 1995 was $600 per ...

  8. Anxiety, Depression, and Exercise

    Microsoft Academic Search

    Patricia M. Mihevic

    1981-01-01

    Experimental and clinical investigations of the effects of acute and chronic exercise on state anxiety or tension and depression are reviewed. Proposed explanations for the association of exercise with improved mood states are also discussed.

  9. Treatment of bipolar depression.

    PubMed

    Berk, Michael; Berk, Lesley; Davey, Christopher G; Moylan, Steven; Giorlando, Francesco; Singh, Ajeet B; Kalra, Harish; Dodd, Seetal; Malhi, Gin S

    2013-09-16

    Depression is usually the predominant phase in bipolar disorder, causes the most psychosocial disability, and carries significant risk of suicide. The management of bipolar depression is relatively under-studied and poses significant challenges for clinicians. There is substantial dissent regarding optimal pharmacotherapy for bipolar depression, particularly around the role of antidepressants. Individual and combination pharmacotherapy should be integrated into a personalised psychosocial and lifestyle package of interventions that considers the person's clinical profile and preferences. The relative lack of evidence relating to optimal strategies, especially when bipolar depression occurs with common comorbidities, poses challenges and requires further research. A flexible approach and evidence-based combinations of treatments can provide effective strategies for improving quality of life and reducing morbidity and mortality. PMID:25370283

  10. Depression in glioma 

    E-print Network

    Rooney, Alasdair Grant

    2011-11-25

    BACKGROUND Few high-quality observational studies have been conducted to examine clinically relevant features of emotional distress and Major Depressive Disorder (MDD) in adults with primary cerebral glioma. Our knowledge ...

  11. Understanding Depression (For Parents)

    MedlinePLUS

    ... be able to help. These professionals have your child's welfare at heart and all information shared with them during therapy is kept confidential. Treating Depression Don't put off your child's treatment. Early detection and diagnosis are key in ...

  12. Adjustments and Depression

    MedlinePLUS Videos and Cool Tools

    ... serious medical disorder that affects your thoughts, feelings, physical health and behaviors as well as other aspects of your life. Depression can cause physical and psychological symptoms. It can worsen pain, make ...

  13. Inflammation and depression.

    PubMed

    Zunszain, Patricia A; Hepgul, Nilay; Pariante, Carmine M

    2013-01-01

    Major depressive disorder (MDD) is a complex illness and it is likely that alterations in several interacting systems underlie its pathogenesis. Numerous hypotheses have been proposed to elucidate its origins. The inflammatory hypothesis emphasises the role of psycho-neuroimmunological dysfunctions. This is based on several observations: subsets of MDD patients have an altered peripheral immune system, with impaired cellular immunity and increased levels of proinflammatory cytokines; cytokines can influence neurotransmitter metabolism, neuroendocrine function and regional brain activity, all of which are relevant to depression; acute administration of cytokines causes sickness behaviour which shares features with depression, and patients undergoing cytokine treatment develop depressive symptoms. In this chapter, we discuss the evidence linking inflammation and MDD, looking at data from clinical and animal studies, the role of stress, possible mechanisms and the involvement of genetic polymorphisms. Further understanding of pathways involved is still needed. This will be vital for the identification of new drug targets and preventative strategies. PMID:22553073

  14. Couple therapy for depression.

    PubMed

    Whisman, Mark A; Beach, Steven R H

    2012-05-01

    Relationship problems and depression often influence one another in a bidirectional, recursive fashion. Results from several clinical trials have demonstrated that couple therapy is effective in improving depression and reducing relationship problems. In this article, we describe an approach to working with depression in partnered individuals who are also unhappy in their relationship. This cognitive-behavior approach strives to (a) eliminate major stressors and reestablish positive activities in the relationship, (b) improve communication and problem solving in the relationship, and (c) solidify gains made in therapy and prevent relapse. The typical course of therapy is described and demonstrated in a case illustration. Couple therapy is a promising treatment for depressed individuals in distressed relationships. PMID:22499085

  15. Probability of freezing in the freeze-avoiding beetle larvae Cucujus clavipes puniceus (Coleoptera: Cucujidae) from interior Alaska.

    PubMed

    Sformo, T; McIntyre, J; Walters, K R; Barnes, B M; Duman, J

    2011-08-01

    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

  16. ADHD and comorbid depression

    Microsoft Academic Search

    Lucy Cumyn; Lisa French; Lily Hechtman

    2009-01-01

    Attention-deficit\\/hyperactivity disorder (ADHD) is prevalent, chronic, and often comorbid with other disorders. This article\\u000a reviews the literature on ADHD and comorbid major depressive disorder from childhood through adolescence and adulthood. We\\u000a also report findings from a study we conducted that examined the prevalence of ADHD and comorbid major depression in adults.\\u000a Diagnostic history data were analyzed in 524 adults (308

  17. Substance Abuse and Depression

    Microsoft Academic Search

    John A. Renner; Jeffrey Baxter; Joji Suzuki; Domenic A. Ciraulo

    \\u000a Depression, complicated by substance abuse, is a common clinical problem and is often associated with poor clinical outcomes.\\u000a Clinicians need to understand the relationship between these two conditions and must adjust their treatment plans to address\\u000a both disorders simultaneously. It is critical that the clinician not confuse a substance-induced mood disorder with an independent\\u000a depressive disorder. Unfortunately, the relationship between

  18. Stroke-related depression

    Microsoft Academic Search

    Kenji Narushima; Robert G. Robinson

    2002-01-01

    Stroke represents a major health problem in the United States and most European and Asian countries. Depression is probably\\u000a the most common and serious emotional disorder following stroke. Post-stroke depression (PSD) has frequently been overlooked\\u000a and left untreated. Prevention of PSD or successful intervention in the early phase may prevent premature deaths as well as\\u000a facilitate rehabilitation, reduce costs, and

  19. Emerging from Depression: Treatment of Adolescent Depression Using the Major Treatment Models of Adult Depression.

    ERIC Educational Resources Information Center

    Long, Kathleen M.

    Noting that adolescents who commit suicide are often clinically depressed, this paper examines various approaches in the treatment of depression. Major treatment models of adult depression, which can be directly applied to the treatment of the depressed adolescent, are described. Major treatment models and selected research studies are reviewed in…

  20. [Depression in the workplace].

    PubMed

    Mezerai, Mustapha; Dahane, Abdelkrim; Tachon, Jean-Paul

    2006-05-01

    Depression is the object of a dense literature, and synthesizing it is more of a utopian ideal rather than a concrete possibility. Several specific risk factors for mental health are found in the workplace: work overloads, defective communications, role conflicts, competitive climate, and tolerance of violence. At the same time, few preventive measures have been implemented against mental disorders at work, nor are many protective factors present. One worker in ten suffers from depression, anxiety, stress, or overwork. To be distinguished from "burnout", depressive symptoms must induce clinically significant suffering with substantial deterioration in functioning at work. For depression to be recognized as a workplace accident, the employee must show that it was triggered by an unforeseen and sudden event (or at least one certainly) due to or at work. The causal link between an event at work and the depression must be shown (in particular by expert medical testimony about stress factors and indicators of vulnerability to depression). Its recognition as an occupational disease can be based on the presence of psychosocial factors described by models of workplace stress and on its description by the occupational physician. PMID:16710154

  1. Randomized controlled trial testing the effectiveness of a depression prevention program ('Op Volle Kracht') among adolescent girls with elevated depressive symptoms.

    PubMed

    Wijnhoven, Lieke A M W; Creemers, Daan H M; Vermulst, Ad A; Scholte, Ron H J; Engels, Rutger C M E

    2014-02-01

    Depression rates rise dramatically from the early to late adolescence. Especially young adolescent girls with elevated depressive symptoms are at high risk for developing a depression during adolescence or adulthood. Therefore, the prevention of depression is important especially in this high-risk group. The aim of the present study was to examine the effectiveness of the Cognitive Behavioral Therapy (CBT) component of the depression prevention program 'Op Volle Kracht' (OVK) among Dutch adolescent girls with elevated depressive symptoms. In total, 102 adolescent girls (11-15 years) in the first and second year of secondary school participated in this study. The girls in the experimental group (n?=?50) followed the eight CBT-lessons of OVK and reported depressive symptoms 1 week prior to the start of the lessons, after every lesson, at one-month and 6-months follow-up. The girls in the control group (n?=?52) exclusively reported depressive symptoms at the same time points. Latent Growth Curve Modeling showed that the decrease in depressive symptoms was significantly larger for girls in the experimental group compared to the girls in the control group. Furthermore, it was found that at 6-months follow-up, the girls in the experimental group had significantly lower levels of depressive symptoms compared to the girls in the control group. These findings indicate that the CBT-component of OVK effectively reduces depressive symptoms in short term and possibly prevents the development of a clinical depression. PMID:23893066

  2. SEPARATE PERSONALITY TRAITS FROM STATES TO PREDICT DEPRESSION

    PubMed Central

    Vittengl, Jeffrey; Kraft, Dolores

    2005-01-01

    Results have been inconsistent regarding the ability of personality measures to predict future depression severity levels, leading some researchers to question the validity of personality assessment, especially when patients are acutely depressed. Using a combination of regression and factor analytic techniques, we separated the variance of personality measures into stable trait and variable state-affect components. Findings supported the hypotheses that depression severity measured at different time points would correlate with both stable trait and concurrent state-affect components in personality measures, whereas change in depression severity would correlate with state changes but not with stable trait scores. Thus, personality assessments tap both state affect and trait variance, with the state-affect variance masking the trait variance when patients are depressed. PMID:12755328

  3. Freezing of a two-dimensional fluid into a crystalline phase: density functional approach.

    PubMed

    Jaiswal, Anubha; Singh, Swarn L; Singh, Yashwant

    2013-01-01

    A free-energy functional for a crystal proposed by Singh and Singh [Europhys. Lett. 88, 16005 (2009)] which contains both the symmetry conserved and symmetry broken parts of the direct pair correlation function has been used to investigate the crystallization of a two-dimensional fluid. The results found for fluids interacting via the inverse power potential u(r)=?(?/r)(n) for n=3,6, and 12 are in good agreement with experimental and simulation results. The contribution made by the symmetry broken part to the grand thermodynamic potential at the freezing point is found to increase with the softness of the potential. Our results explain why the Ramakrishnan-Yussouff [Phys. Rev. B 19, 2775 (1979)] free-energy functional gave good account of freezing transitions of hard-core potentials but failed for potentials that have soft core and/or attractive tail. PMID:23410333

  4. A historical perspective on cold tolerance in the Canal Point Sugarcane Breeding Program

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Developing sugarcane cultivars with greater freeze tolerance is an important objective of the USDA-ARS Canal Point breeding program, as temperatures around -3oC (27oF) cause serious sugar yield losses during the harvest season. To estimate if progress was made in freeze tolerance by breeding for can...

  5. The costs of depression.

    PubMed

    Kessler, Ronald C

    2012-03-01

    The data reported herein show clearly that major depression is a commonly occurring and burdensome disorder. The high prevalence, early age of onset, and high persistence of MDD in the many different countries where epidemiologic surveys have been administered confirm the high worldwide importance of depression. Although evidence is not definitive that MDD plays a causal role in its associations with the many adverse outcomes reviewed here, there is clear evidence that depression has causal effects on a number of important mediators, making it difficult to assume anything other than that depression has strong causal effects on many dimensions of burden. These results have been used to argue for the likely cost -effectiveness of expanded depression treatment from a societal perspective. Two separate, large-scale, randomized, workplace depression treatment effectiveness trials have been carried out in the United States to evaluate the cost effectiveness of expanded treatment from an employer perspective. Both trials had positive returns on investment to employers. A substantial expansion of worksite depression care management programs has occurred in the United States subsequent to the publication of these trials. However, the proportion of people with depression who receive treatment remains low in the United States and even lower in other parts of the world. A recent US study found that only about half of workers with MDD received treatment in the year of interview and that fewer than half of treated workers received treatment consistent with published treatment guidelines. Although the treatment rate was higher for more severe cases, even some with severe MDD often failed to receive treatment. The WMH surveys show that treatment rates are even lower in many other developed countries and consistently much lower in developing countries. Less information is available on rates of depression treatment among patients with chronic physical disorders, but available evidence suggests that expanded treatment could be of considerable value. Randomized, controlled trials are needed to expand our understanding of the effects of detection and treatment of depression among people in treatment for chronic physical disorders. In addition, controlled effectiveness trials with long-term follow-ups are needed to increase our understanding of the effects of early MDD treatment interventions on changes in life course role trajectories, role performance, and onset of secondary physical disorders. PMID:22370487

  6. Time-Invariant and Time-Varying Predictors of Depression Symptoms in Primary Care Patients

    PubMed Central

    Weisberg, Risa B.; Strong, David R.; Smith, Marcia; Miller, Ivan W.

    2009-01-01

    Objective: The aims of this study were to examine correlates of depression symptoms, baseline predictors of change in depression symptoms, and time-varying predictors of depression symptoms in a primary care sample. Method: In this study, we assessed depression symptoms and other variables at 3 time points over the course of 6 months in 103 primary care patients with elevated depression symptoms at baseline. Data collection occurred from May 2004 to September 2007. Results: Individuals with lower income levels and those who were not married had a poorer course of depression, as assessed by Center for Epidemiologic Studies Depression Scale score, over time. Several variables fluctuated in concert with depression symptoms within individuals over time. As depression symptoms improved, family functioning, problem-solving, pain, and general health perceptions also improved. A multivariate analysis showed that problem-solving and general health perceptions predicted significant (P < .001) unique variance in fluctuations in depression symptoms within individuals. Conclusions: Care management programs for primary care depression may benefit from the inclusion of psychosocial interventions that directly target variables closely linked to depression, such as problem-solving and general health perceptions. In addition, special efforts must be made to help depressed individuals with low income and less social support. PMID:20098524

  7. Using infrared thermography to study freezing in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Factors that determine when and to what extent a plant will freeze are complex. While thermocouples have served as the main method of monitoring the freezing process in plants, infrared thermography offers distinct advantages, and the use of this latter technology has provided new insights on the p...

  8. Increasing Freezing Tolerance: Kinase Regulation of ICE1.

    PubMed

    Zhan, Xiangqiang; Zhu, Jian-Kang; Lang, Zhaobo

    2015-02-01

    Cold temperatures trigger the ICE1-CBF-COR transcriptional cascade in plants, which reprograms gene expression to increase freezing tolerance. In this issue of Developmental Cell, Ding et al. (2015) report that cold stress activates the protein kinase OST1 to phosphorylate and thereby stabilize and stimulate ICE1. This enhances plant tolerance to freezing temperatures. PMID:25669879

  9. In Vivo Detection of Membrane Injury at Freezing Temperatures

    PubMed Central

    Stout, Darryl G.; Majak, Walter; Reaney, Martin

    1980-01-01

    The release of hydrogen cyanide from Amelanchier alnifolia was monitored at 30 C and ?10 C following lethal freezing at both slow and fast rates. Assuming that hydrogen cyanide release indicates membrane damage, it was concluded that during a fatal freeze-thaw cycle membrane damage occurred during cell contraction and, therefore, was not dependent upon membrane area expansion during thawing. PMID:16661397

  10. In vivo detection of membrane injury at freezing temperatures.

    PubMed

    Stout, D G; Majak, W; Reaney, M

    1980-07-01

    The release of hydrogen cyanide from Amelanchier alnifolia was monitored at 30 C and -10 C following lethal freezing at both slow and fast rates. Assuming that hydrogen cyanide release indicates membrane damage, it was concluded that during a fatal freeze-thaw cycle membrane damage occurred during cell contraction and, therefore, was not dependent upon membrane area expansion during thawing. PMID:16661397

  11. SFT: a consistent checkpointing algorithm with shorter freezing time

    Microsoft Academic Search

    Xiaohui Wei; Jiubin Ju

    1998-01-01

    SFT algorithm, a consistent checkpointing algorithm with shorter freezing time, is presented in this paper. SFT is able to implement fault-tolerance in distributed systems. The features of the algorithm include shorter freezing time, lower overhead, and simple roll backing. To reduce checkpointing time, a special control message (Munblock) is used to ensure that at any given time a process can

  12. Understanding freeze stress in biological tissues: thermodynamics of interfacial water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A thermodynamic approach to distinguish forms of freeze energy that injure plants as the temperature decreases is developed. The pattern resulting from this analysis dictated the sequence of thermal requirements for water to exist as an independent state. Improvement of freezing tolerance in biolo...

  13. Freeze movement on the local level: prospects for success

    Microsoft Academic Search

    Wernette

    1985-01-01

    This paper uses the findings and observations of two past studies of social movements to assess the chances of success of a local Freeze organization. Past studies show that movement organizations with certain types of goals, tactics, organizational characteristics, and membership-recruitment techniques experience above-average rates of success. After summarizing these findings, the local Freeze organization is described along the relevant

  14. Observation of a freezing drizzle episode: A case study

    NASA Astrophysics Data System (ADS)

    Fernández-González, S.; Valero, F.; Sanchez, Jose L.; Gascón, E.; López, L.; García-Ortega, E.; Merino, A.

    2014-11-01

    On 5 February 2012 an episode of freezing precipitation took place in the Guadarrama Mountains, at the center of the Iberian Peninsula. This precipitation affected high elevations, where temperatures remained below freezing because of snow cover that had accumulated from snowfall during the previous days. The case study was recorded by surface synoptic observations (SYNOP) at Navacerrada Pass meteorological observatory (belonging to the National Weather Service of Spain). To study winter cloud systems during the TEcoAgua project, a multichannel ground-based microwave radiometer (MMWR), Micro Rain Radar (MRR-2), and isothermal cloud chamber were installed in the study area, thus permitting the monitoring of the freezing precipitation event. Analysis using Meteosat Second Generation (MSG) satellite data and observations permitted the determination of factors that triggered the freezing precipitation event. Freezing drizzle was interspersed with the passage of a warm and cold front. During frontal passage, mid-level clouds inhibited the generation of freezing drizzle, with snowfall recorded in the study area. However, during the period between the two fronts, an absence of mid-level clouds permitted low-level orographic clouds to persist upwind of the mountain system, producing freezing drizzle at the surface. The decisive factors for the generation of freezing drizzle were high humidity at low levels, weak mesoscale updrafts caused by the topography, stability at mid levels, cloud-top temperatures warmer than - 15 °C, and low concentrations of ice nuclei.

  15. Effects of freezes on survival of Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus in Florida is occasionally subjected to freezing temperatures. No information was available on the effect of freezing temperatures on mortality of Asian citrus psyllid (Diaphorina citri) in Florida. Studies were therefore initiated to assess mortality rates of D. citri eggs, nymphs and adults...

  16. Cytoplasmic actomyosin fibrils after preservation with high pressure freezing.

    PubMed

    Wolf, K V; Stockem, W; Wohlfarth-Bottermann, K E

    1981-01-01

    The fine structure of the actomyosin system of Physarum polycephalum was investigated in vitrified specimens after applying a pressure of greater than 2.1 kbar and freezing rates of 500 to 5,000 degrees C/s. The frozen specimens were either freeze-substituted or freeze-fractured and compared with material processed according to conventional methods of freeze-etching preparation. Artifactual alterations, as seen in the form of destroyed areas of the cytoplasm after chemical fixation, were not observed after freeze-substitution. However, small ice crystals formed by recrystallization within most of the cytoplasmic actomyosin fibrils prevented a fine structural analysis. Such a destruction of the fibrillar fine structure was not found after freeze-etching. In replicas of deep-etched objects 10 nm-thick filaments were localized, which could be conclusively identified as F-actin. The actin filaments are located randomly in the peripheral cytoplasm forming the cell cortex. By the process of parallel aggregation, the filaments can be differentiated to fibrils. Thick myosin filaments were not observed. However, structures resembling cross bridges between single actin filaments suggest the existence of oligomeric myosin. The present investigation shows that, in addition to biomembranes, other cytoplasmic differentiations such as components of the groundplasm can be successfully demonstrated employing the deep-etching technique when the freezing methods are improved by avoiding freeze-protection pretreatments. PMID:7195774

  17. Stopping biological time: The freezing of living cells

    SciTech Connect

    Mazur, P.

    1987-01-01

    The fundamental physical-chemical events that occur during the freezing and thawing of cells are outlined and the manner in which cell permeability determines the response of the cell to freezing is discussed both in terms of physical response and in terms of survival. 40 refs., 12 figs.

  18. Prospective Primary School Teachers' Perceptions on Boiling and Freezing

    ERIC Educational Resources Information Center

    Senocak, Erdal

    2009-01-01

    The aim of this study was to investigate the perceptions of prospective primary school teachers on the physical state of water during the processes of boiling and freezing. There were three stages in the investigation: First, open-ended questions concerning the boiling and freezing of water were given to two groups of prospective primary school…

  19. Large scale synthesis of nanostructured zirconia-based compounds from freeze-dried precursors

    SciTech Connect

    Gomez, A.; Villanueva, R.; Vie, D.; Murcia-Mascaros, S.; Martinez, E.; Beltran, A. [Institut de Ciencia dels Materials, Parc Cientific, Universitat de Valencia, PO Box 22085, 46071 Valencia (Spain); Sapina, F., E-mail: fernando.sapina@uv.es [Institut de Ciencia dels Materials, Parc Cientific, Universitat de Valencia, PO Box 22085, 46071 Valencia (Spain); Vicent, M.; Sanchez, E. [Instituto de Tecnologia Ceramica-Asociacion de Investigacion de las Industrias Ceramicas, Universitat Jaume I, 12006 Castellon (Spain)

    2013-01-15

    Nanocrystalline zirconia powders have been obtained at the multigram scale by thermal decomposition of precursors resulting from the freeze-drying of aqueous acetic solutions. This technique has equally made possible to synthesize a variety of nanostructured yttria or scandia doped zirconia compositions. SEM images, as well as the analysis of the XRD patterns, show the nanoparticulated character of those solids obtained at low temperature, with typical particle size in the 10-15 nm range when prepared at 673 K. The presence of the monoclinic, the tetragonal or both phases depends on the temperature of the thermal treatment, the doping concentration and the nature of the dopant. In addition, Rietveld refinement of the XRD profiles of selected samples allows detecting the coexistence of the tetragonal and the cubic phases for high doping concentration and high thermal treatment temperatures. Raman experiments suggest the presence of both phases also at relatively low treatment temperatures. - Graphical abstract: Zr{sub 1-x}A{sub x}O{sub 2-x/2} (A=Y, Sc; 0{<=}x{<=}0.12) solid solutions have been prepared as nanostructured powders by thermal decomposition of precursors obtained by freeze-drying, and this synthetic procedure has been scaled up to the 100 g scale. Highlights: Black-Right-Pointing-Pointer Zr{sub 1-x}A{sub x}O{sub 2-x/2} (A=Y, Sc; 0{<=}x{<=}0.12) solid solutions have been prepared as nanostructured powders. Black-Right-Pointing-Pointer The synthetic method involves the thermal decomposition of precursors obtained by freeze-drying. Black-Right-Pointing-Pointer The temperature of the thermal treatment controls particle sizes. Black-Right-Pointing-Pointer The preparation procedure has been scaled up to the 100 g scale. Black-Right-Pointing-Pointer This method is appropriate for the large-scale industrial preparation of multimetallic systems.

  20. Nonsomatic treatment of depression.

    PubMed

    Sherrill, Joel T; Kovacs, Maria

    2002-07-01

    There is solid evidence that active and goal-oriented cognitive-behavioral or relationship-focused therapies are generally superior to more generic therapies or to no treatment for clinically diagnosed and for undiagnosed but symptomatic youths. Between 50% to 87% of diagnosed youths who received a targeted treatment had recovered from their depressive episodes, in comparison to 21% to 75% of those who received some other generic therapy and 5% to 48% of wait-listed youths. The cognitive behavioral and relationship-oriented interventions that were tested tended to be even more successful in reducing depressive symptoms in school-based samples, possibly because the participants in the school-based studies may have been less disturbed than the clinically diagnosed cases. Although the targeted treatments generally yielded better results than the comparison conditions, the targeted interventions seem to be similarly successful in ameliorating depression. Determining which psychosocial therapy works best for a given depressed youngster remains problematic. As noted in recent reviews [30,46,47], little attention has been devoted to which interventions, or parts of an intervention, are likely to be effective with children with various characteristics. This issue acquires added importance because in some diagnosed samples half or more of the treated participants were still in a depressive episode at the end of the trial. Likewise, in intervention studies involving symptomatic, school-based youngsters, not all children improved, and gains were not uniform across domains of functioning (e.g., severity of depression, self-esteem, global functioning). Possibly, for some of the nonresponders, the participant's characteristics and relevant problems and the target interventions were mismatched. For example, a depressed youth with a long history of highly dysfunctional relationships may not respond optimally to a therapy focusing on negative cognitions; alternatively, interpersonal therapy may not be the most effective treatment for a youth dispositionally inclined to negative ruminations about the self and for whom relationship issues are not the most relevant. Empiric information about the relationship between the underlying processes presumed to account for the onset and maintenance of depression and recovery from depression is limited. Few studies of youths provide direct evidence tht cognitive-behavioral interventions change depressogenic cognitions, explanatory style, and pleasent events, among others, that relationship-focused approaches predictably alter relevant interpersonal processes, or that improvements in these domains relate to overall depression outcomes. Admittedly, the designs of extent studies typically preclude conclusions about the relationship between changes in target processes and improvement in depression or about treatment specificity. More compelling evidence linking changes in targeted mechanisms to decreases in depressive symptoms comes from a controlled prevention trial involving 10- to 13-year-olds that used cognitive restructuring, social problem-solving, or a combination intervention [48]. According to the results, changes in explanatory style were related to decreased depression and accounted for a significant portion of the variance in changes in depression even after controlling for treatment assignment. Further research along such lines may help identify which treatment may be most effective for a patient with a given set of characteristics. To improve patients' response rates to specific treatments, it also would be helpful to understand better the impact of other attributes, such as psychiatric comorbidity, and contextual factors, such as parental psychopathology, on the process of recovery. With few exceptions [25], however, such variable have not yet received sufficient attention. Recent reviews also have noted that researchers typically use multi-component interventions in treatmenttrials [46,47]. This design an make it difficult to identify which particular treatment ingredient is instrumental

  1. Lifestyle medicine for depression

    PubMed Central

    2014-01-01

    The prevalence of depression appears to have increased over the past three decades. While this may be an artefact of diagnostic practices, it is likely that there are factors about modernity that are contributing to this rise. There is now compelling evidence that a range of lifestyle factors are involved in the pathogenesis of depression. Many of these factors can potentially be modified, yet they receive little consideration in the contemporary treatment of depression, where medication and psychological intervention remain the first line treatments. “Lifestyle Medicine” provides a nexus between public health promotion and clinical treatments, involving the application of environmental, behavioural, and psychological principles to enhance physical and mental wellbeing. This may also provide opportunities for general health promotion and potential prevention of depression. In this paper we provide a narrative discussion of the major components of Lifestyle Medicine, consisting of the evidence-based adoption of physical activity or exercise, dietary modification, adequate relaxation/sleep and social interaction, use of mindfulness-based meditation techniques, and the reduction of recreational substances such as nicotine, drugs, and alcohol. We also discuss other potential lifestyle factors that have a more nascent evidence base, such as environmental issues (e.g. urbanisation, and exposure to air, water, noise, and chemical pollution), and the increasing human interface with technology. Clinical considerations are also outlined. While data supports that some of these individual elements are modifiers of overall mental health, and in many cases depression, rigorous research needs to address the long-term application of Lifestyle Medicine for depression prevention and management. Critically, studies exploring lifestyle modification involving multiple lifestyle elements are needed. While the judicious use of medication and psychological techniques are still advocated, due to the complexity of human illness/wellbeing, the emerging evidence encourages a more integrative approach for depression, and an acknowledgment that lifestyle modification should be a routine part of treatment and preventative efforts. PMID:24721040

  2. 29 CFR 784.148 - General scope of processing, freezing, and curing activities.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...false General scope of processing, freezing, and curing activities. 784.148...and Aquatic Products Processing, Freezing, and Curing § 784.148 General scope of processing, freezing, and curing activities....

  3. 29 CFR 784.148 - General scope of processing, freezing, and curing activities.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...false General scope of processing, freezing, and curing activities. 784.148...and Aquatic Products Processing, Freezing, and Curing § 784.148 General scope of processing, freezing, and curing activities....

  4. 29 CFR 784.148 - General scope of processing, freezing, and curing activities.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...false General scope of processing, freezing, and curing activities. 784.148...and Aquatic Products Processing, Freezing, and Curing § 784.148 General scope of processing, freezing, and curing activities....

  5. 3 CFR - Freezing Federal Employee Pay Schedules and Rates That Are Set By Administrative Discretion

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Freezing Federal Employee Pay Schedules and Rates... Memorandum of December 22, 2010 Freezing Federal Employee Pay Schedules and Rates...correspondingly reduced to reflect the freezing of the employees' base pay...

  6. 29 CFR 784.148 - General scope of processing, freezing, and curing activities.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...false General scope of processing, freezing, and curing activities. 784.148...and Aquatic Products Processing, Freezing, and Curing § 784.148 General scope of processing, freezing, and curing activities....

  7. 29 CFR 784.148 - General scope of processing, freezing, and curing activities.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...false General scope of processing, freezing, and curing activities. 784.148...and Aquatic Products Processing, Freezing, and Curing § 784.148 General scope of processing, freezing, and curing activities....

  8. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25...Miscellaneous Equipment § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained...

  9. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...2012-01-01 2012-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25...Miscellaneous Equipment § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained...

  10. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25...Miscellaneous Equipment § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained...

  11. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...2013-01-01 2013-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25...Miscellaneous Equipment § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained...

  12. 14 CFR 25.1455 - Draining of fluids subject to freezing.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Draining of fluids subject to freezing. 25.1455 Section 25...Miscellaneous Equipment § 25.1455 Draining of fluids subject to freezing. If fluids subject to freezing may be drained...

  13. A search for the Mpemba effect: When hot water freezes faster then cold water

    E-print Network

    Brownridge, James D

    2010-01-01

    An explanation for why hot water will sometime freeze more rapidly than cold water is offered. Two specimens of water from the same source will often have different spontaneous freezing temperatures; that is, the temperature at which freezing begins. When both specimens supercool and the spontaneous freezing temperature of the hot water is higher than that of the cold water, then the hot water will usually freeze first, if all other conditions are equal and remain so during cooling. The probability that the hot water will freeze first if it has the higher spontaneous freezing temperature will be larger for a larger difference in spontaneous freezing temperature. Heating the water may lower, raise or not change the spontaneous freezing temperature. The keys to observing hot water freezing before cold water are supercooling the water and having a significant difference in the spontaneous freezing temperature of the two water specimens. We observed hot water freezing before cold water 28 times in 28 attempts und...

  14. Photomicrographic Investigation of Spontaneous Freezing Temperatures of Supercooled Water Droplets

    NASA Technical Reports Server (NTRS)

    Dorsch, R. G.; Hacker, P. T.

    1950-01-01

    A photomicrographic technique for investigating eupercooled. water droplets has been devised and. used. to determine the spontaneous freezing temperatures of eupercooled. water droplets of the size ordinarily found. in the atmosphere. The freezing temperatures of 4527 droplets ranging from 8.75 to 1000 microns in diameter supported on a platinum surface and 571 droplets supported on copper were obtained. The average spontaneous freezing temperature decreased with decrease in the size of the droplets. The effect of size on the spontaneous freezing temperature was particularly marked below 60 microns. Frequency-distribution curves of the spontaneous freezing temperatures observed for droplets of a given size were obtained. Although no droplet froze at a temperature above 20 0 F, all droplets melted at 32 F. Results obtained with a copper support did not differ essentially from those obtained with a platinum surface.

  15. Freezing of HNO{sub 3}/H{sub 2}SO{sub 4}/H{sub 2}O solutions at stratospheric temperatures: Nucleation statistics and experiments

    SciTech Connect

    Koop, T.; Luo, B.; Biermann, U.M.; Crutzen, P.J.; Peter, T. [Max Planck Inst. for Chemistry, Mainz (Germany)] [Max Planck Inst. for Chemistry, Mainz (Germany)

    1997-02-06

    Calorimetric freezing experiments with aqueous sulfuric and nitric acid solutions are presented and applied to the formation of polar stratospheric clouds (PSCs). We show that the nucleation of hydrates from these solutions is a stochastic process and that nucleation rates and their uncertainties can be determined using Poisson statistics. Under thermodynamic equilibrium conditions above the ice frost point, the homogeneous nucleation rates of stratospheric aerosols are exceedingly low, ruling out homogeneous freezing as a pathway for PSC formation. Several stratospherically important substrates were tested concerning their ability to induce heterogeneous nucleation. None of the experiments indicated a relevant enhancement of the freezing probability of liquid aerosols. Moreover, the experiments reveal that the freezing process of the solutions under stratospheric conditions is limited by the nucleation rates of the hydrates, rather than their crystal growth rates, thus ruling out the possibility of a glassy state of stratospheric aerosol droplets. Also, we argue why a glacial state of the aerosols seems to be unlikely. The only processes leading to freezing of the hydrates appear to be the heterogeneous nucleation on water ice crystals forming below the frost point and the homogeneous freezing of almost binary HNO{sub 3}/H{sub 2}O droplets with H{sub 2}SO{sub 4} concentrations below approximately 0.01 wt%. 68 refs., 18 figs., 4 tabs.

  16. STEFINS: a steel freezing integral simulation program

    SciTech Connect

    Frank, M.V.

    1980-09-01

    STEFINS (STEel Freezing INtegral Simulation) is a computer program for the calculation of the rate of solidification of molten steel on solid steel. Such computations arize when investigating core melt accidents in fast reactors. In principle this problem involves a coupled two-dimensional thermal and hydraulic approach. However, by physically reasonable assumptions a decoupled approach has been developed. The transient solidification of molten steel on a cold wall is solved in the direction normal to the molten steel flow and independent from the solution for the molten steel temperature and Nusselt number along the direction of flow. The solutions to the applicable energy equations have been programmed in cylindrical and slab geometries. Internal gamma heating of steel is included.

  17. Hot water can freeze faster than cold?!?

    E-print Network

    Jeng, M

    2005-01-01

    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 story of the secondary school student, Erasto Mpemba, who reintroduced the effect to the twentieth century scientific community. The phenomenon, while simple to describe, is deceptively complex, and illustrates numerous important issues about the scientific method: the role of skepticism in scientific inquiry, the influence of theory on experiment and observation, the need for precision in the statement of a scientific hypothesis, and the nature of falsifiability. We survey proposed theoretical mechanisms for the Mpemba effect, and the results of modern experiments on the phenomenon. Studies of the observation that hot water pipes are more ...

  18. Freezing of Martian streams under climatic conditions

    NASA Technical Reports Server (NTRS)

    Carr, M. H.

    1984-01-01

    The valley networks of Mars are widely believed to have formed at a time when climatic conditions on the planet were significantly different from those that currently prevail. This view arises from the following observations: (1) the valleys form integrated branching networks which suggests fluid drainage, and water is the most plausible fluid, (2) the present atmosphere contains only minute amounts of water, (3) the networks appear to be more akin to terrestrial valleys that are eroded by streams of modest discharges than features that form by catastrophic floods, and (4) small streams of water will rapidly freeze under present climatic conditions. Climatic conditions at the time of formation of the valleys are studied based on the assumption that they were cut by running water.

  19. Free-energy functional for freezing transitions: Hard sphere systems freezing into crystalline and amorphous structures

    E-print Network

    Swarn Lata Singh; Atul S. Bharadwaj; Yashwant Singh

    2011-01-31

    A free-energy functional that contains both the symmetry conserved and symmetry broken parts of the direct pair correlation function has been used to investigate the freezing of a system of hard spheres into crystalline and amorphous structures. The freezing parameters for fluid-crystal transition have been found to be in very good agreement with the results found from simulations. We considered amorphous structures found from the molecular dynamics simulations at packing fractions $\\eta$ lower than the glass close packing fraction $\\eta_{J}$ and investigated their stability compared to that of a homogeneous fluid. The existence of free-energy minimum corresponding to a density distribution of overlapping Gaussians centered around an amorphous lattice depicts the deeply supercooled state with a heterogeneous density profile.

  20. What happens in freezing bodies? Experimental study of histological tissue change caused by freezing injuries.

    PubMed

    Schäfer, A T; Kaufmann, J D

    1999-06-28

    In order to evaluate histological features of freezing damages to human tissue after death, we froze samples of liver and heart tissue to temperatures of -12 degrees C, -28 degrees C and -80 degrees C, and stored them for 24 and 72 h, respectively, at those temperatures. After thawing and routine preparation for histology, the samples were evaluated both by microscope and with an electronic image analyzer. In all cases, we found extended extracellular spaces and shrunken cells resulting from the freeze-thaw cycle. These features were more pronounced in tissues stored for longer durations. Such findings seem to be typical of tissue that has been frozen prior to examination. Two cases of dead bodies found outdoors at subzero temperatures demonstrate that formerly frozen and unfrozen tissues can be distinguished histologically. The findings are examined in relation to the fundamental laws of cryobiology. PMID:10464930

  1. Evaluation and Validation of the Messinger Freezing Fraction

    NASA Technical Reports Server (NTRS)

    Anderson, David N.; Tsao, Jen-Ching

    2005-01-01

    One of the most important non-dimensional parameters used in ice-accretion modeling and scaling studies is the freezing fraction defined by the heat-balance analysis of Messinger. For fifty years this parameter has been used to indicate how rapidly freezing takes place when super-cooled water strikes a solid body. The value ranges from 0 (no freezing) to 1 (water freezes immediately on impact), and the magnitude has been shown to play a major role in determining the physical appearance of the accreted ice. Because of its importance to ice shape, this parameter and the physics underlying the expressions used to calculate it have been questioned from time to time. Until now, there has been no strong evidence either validating or casting doubt on the current expressions. This paper presents experimental measurements of the leading-edge thickness of a number of ice shapes for a variety of test conditions with nominal freezing fractions from 0.3 to 1.0. From these thickness measurements, experimental freezing fractions were calculated and compared with values found from the Messinger analysis as applied by Ruff. Within the experimental uncertainty of measuring the leading-edge thickness, agreement of the experimental and analytical freezing fraction was very good. It is also shown that values of analytical freezing fraction were entirely consistent with observed ice shapes at and near rime conditions: At an analytical freezing fraction of unity, experimental ice shapes displayed the classic rime shape, while for conditions producing analytical freezing fractions slightly lower than unity, glaze features started to appear.

  2. Investigation of the stabilizing effects of hydroxyethyl cellulose on LDH during freeze drying and freeze thawing cycles.

    PubMed

    Al-Hussein, Anas; Gieseler, Henning

    2015-01-01

    The objective of this study was to investigate both the cryoprotective and lyoprotective effects of the polymer hydroxyethyl cellulose (HEC) on the model protein lactate dehydrogenase (LDH) during freeze thawing and freeze drying cycles. The effect of annealing on both protein stability and the physical state of HEC was evaluated. HEC was used as a sole excipient in the protein formulations, and its stabilizing was compared to that of other excipients which are commonly used in freeze dried protein formulations. Furthermore, other quality aspects of the freeze dried samples containing solely HEC were investigated, such as, reconstitution time and product elegance. Protein stability was evaluated functionally by measuring the activity recovery of the model protein LDH. The physical state of HEC after freeze drying was investigated and compared to this of other studied solutes using differential scanning calorimetry and X-ray powder diffractometry. HEC showed superior cryoprotective effects on LDH during freeze thawing, and considerable lyoprotective effects during the freeze drying process. Annealing had limited influence on the stabilizing effect of HEC. The extensive reconstitution times of the HEC lyophilisates could be greatly improved by incorporation of the surfactant Tween 80 into the formulations prior to freeze drying. PMID:24286265

  3. Mesophyll freezing and effects of freeze dehydration visualized by simultaneous measurement of IDTA and differential imaging chlorophyll fluorescence.

    PubMed

    Hacker, Jürgen; Spindelböck, Joachim Paul; Neuner, Gilbert

    2008-11-01

    Infrared differential thermal analysis (IDTA) and differential imaging chlorophyll fluorescence (DIF) were employed simultaneously to study the two-dimensional pattern of ice propagation in leaves and mesophyll freeze dehydration as detected by a significant increase of basic chlorophyll fluorescence (F(0)). IDTA and DIF technique gave different insights into the freezing process of leaves that was highly species-specific. IDTA clearly visualized the freezing process consisting of an initial fast spread of ice throughout the vascular system followed by mesophyll freezing. While mesophyll freezing was homogeneously in Poa alpina, Rhododendron ferrugineum and Senecio incanus as determined by IDTA, DIF showed a distinct pattern only in S. incanus, with the leaf tips being affected earlier. In Cinnamomum camphora, a mottled freezing pattern of small mesophyll compartments was observed by both methods. In IDTA images, a random pattern predominated, while in DIF images, compartments closer to lower order veins were affected earlier. The increase of F(0) following mesophyll freezing started after a species-specific time lag of up to 26 min. The start of the F(0) increase and its slope were significantly enhanced at lower temperatures, which suggest a higher strain on mesophyll protoplasts when freezing occurs at lower temperatures. PMID:18761699

  4. Sex Differences in Depression in Patients with Multiple Sclerosis Andrae J. Laws, McNair Scholar, Penn State University

    E-print Network

    Omiecinski, Curtis

    171 Sex Differences in Depression in Patients with Multiple Sclerosis Andrae J. Laws, Mc depression at some point during their lifetime, a rate that far exceeds what is found in the general population. This study examined sex differences in depression in 80 female and 17 male MS patients

  5. Interpersonal Sensitivity, Romantic Stress, and the Prediction of Depression: A Study of Inner-City, Minority Adolescent Girls

    Microsoft Academic Search

    Christie J. Rizzo; Shannon E. Daley; Brent H. Gunderson

    2006-01-01

    The role of interpersonal sensitivity in the relation between romantic stress and depression was examined in 55 adolescent girls from an inner-city high school. Depression, interpersonal sensitivity, and chronic and episodic romantic stress were measured at two time points, 6 months apart. Interpersonal sensitivity was found to moderate the longitudinal relation between romantic stress (both chronic and episodic) and depression.

  6. Survival mechanisms of vertebrate ectotherms at subfreezing temperatures: applications in cryomedicine

    Microsoft Academic Search

    JON P. COSThNZO; RICHARD E. LEE; ARTHUR L. DCVRIES; TINGCEUNG WANG; JACK R. LAYNE

    Various marine fishes, amphibians, and reptiles survive at temperatures several degrees below the freezing point of their body fluids by virtue of adaptive mechanisms that promote freeze avoidance or freeze tolerance. Freezing is avoided by a colligative depression of the blood freezing point, supercooling of the body fluids, or the biosynthesis of unique antifreeze proteins that inhibit the propagation of

  7. Feasibility of high pressure freezing with freeze substitution after long-term storage in chemical fixatives.

    PubMed

    Venter, Chantelle; Van Der Merwe, Christiaan Frederick; Oberholzer, Hester Magdalena; Bester, Megan Jean; Taute, Helena

    2013-09-01

    Fixation of biological samples is an important process especially related to histological and ultrastructural studies. Chemical fixation was the primary method of fixing tissue for transmission electron microscopy for many years, as it provides adequate preservation of the morphology of cells and organelles. High pressure freezing (HPF) and freeze substitution (FS) is a newer alternative method that rapidly freezes non-cryoprotected samples that are then slowly heated in the FS medium, allowing penetration of the tissue to insure adequate fixation. This study addresses several issues related to tissue preservation for electron microscopy. Using mice liver tissue as model the difference between samples fixed chemically or with HPF immediately after excision, or stored before chemical or HPF fixation were tested with specific focus on the nuclear membrane. Findings are that immediate HPF is the method of choice compared to chemical fixation. Of the chemical fixatives, immediate fixation with 2.5% glutaraldehyde (GA)/formaldehyde (FA) is the best in preserving membrane morphology, 2.5% GA can be used as alternative for stored and then chemically processed samples, with 10% formalin being suitable as a storage medium only if followed by HPF fixation. Overall, storage leads to lower ultrastructural preservation, but HPF with FS can minimize these artifacts relative to other processing protocols. PMID:23818457

  8. Hypothyroidism and Depression

    PubMed Central

    Dayan, Colin M.; Panicker, Vijay

    2013-01-01

    Background: A relationship between hypothyroidism and depression has been assumed for many years; however, the true nature of this association has been difficult to define with many conflicting studies. In recent years, our knowledge in this area has increased significantly with large cohort studies and genetically driven studies being published. Objectives: We reviewed the literature on thyroid function and depression to determine if this relationship has been clarified. Methods: We performed a search on the Pubmed database using the terms ‘thyroid? ’ and ‘mental health? ’, ‘depression? ’ and ‘well-being? ’. Results: Large epidemiological studies generally suggest no association between thyroid function and depression in subjects without thyroid disease. Subjects on thyroxine have poorer psychological well-being than subjects with no thyroid disease even if biochemically euthyroid, they also show an association between thyroid function and well-being. Whilst there is some early evidence that genetic factors can influence well-being on thyroxine and response to combination therapy, there is also evidence to suggest that much morbidity on thyroxine may be due to initial misdiagnosis and mis-attribution of symptoms. Conclusion: Despite the large number of studies, the relationship between thyroid function and depression remains poorly defined. Clarification of the proportion of subjects on thyroxine incorrectly may assist the large (perhaps genetically driven) studies needed to move forward in this area, as it is expected that they cloud the results. PMID:24847450

  9. Nature against depression.

    PubMed

    El-Alfy, A T; Abourashed, E A; Matsumoto, R R

    2012-01-01

    Depression is a major health problem currently recognized as a leading cause of morbidity worldwide. In the United States alone, depression affects approximately 20% of the population. With current medications suffering from major shortcomings that include slow onset of action, poor efficacy, and unwanted side effects, the search for new and improved antidepressants is ever increasing. In an effort to evade side effects, people have been resorting to popular traditional herbal medicines to relieve the symptoms of depression, and there is a need for more empirical knowledge about their use and effectiveness. This review provides an overview of the current knowledge state regarding a variety of natural plant products commonly used in depression. Herbal medicines discussed that have been used in clinical trials for the treatment of mild to moderate depression states include the popular St. John's wort, saffron, Rhodiola, lavender, Echium, and the Chinese formula banxia houpu. In addition, new emerging herbal products that have been studied in different animal models are discussed including Polygala tenuifolia, the traditional Chinese herbal SYJN formula, gan mai da zao, and Cannabis sativa constituents. A comprehensive review of the chemical, pharmacological, and clinical aspects of each of the reviewed products is provided. Finally, recent preclinical studies reporting the antidepressant action of marine-derived natural products are discussed at the end of the review. PMID:22414105

  10. Depression and Coronary Heart Disease

    PubMed Central

    Davidson, Karina W.

    2012-01-01

    There are exciting findings in the field of depression and coronary heart disease. Whether diagnosed or simply self-reported, depression continues to mark very high risk for a recurrent acute coronary syndrome or for death in patients with coronary heart disease. Many intriguing mechanisms have been posited to be implicated in the association between depression and heart disease, and randomized controlled trials of depression treatment are beginning to delineate the types of depression management strategies that may benefit the many coronary heart disease patients with depression. PMID:23227360

  11. Clarification on Mechanical Characteristic in State of Stress of Osteoarthritis of the Hip Joint Using Stress Freezing Method

    NASA Astrophysics Data System (ADS)

    Maezaki, Nobutaka; Ezumi, Tsutomu; Hachiya, Masashi

    In this research, the Osteoarthritis of Hip Joint was pick up, the 3-dimensional stress freezing method of photoelastic method was applied, and the state of the stress in the normality hip joint and the transformable hip joint was examined. The direction and the singular point of principal stress and stress distribution were experimentally examined. At result, The Osteoarthritis of Hip Joint touches by 2 points, Osteoarthritis of Hip Joint occurrence of the new singular point with flat of the femoral head, They change the direction of the principal stress line in an existing singular point is cause.

  12. [A new proposal for the diagnosis of depression].

    PubMed

    Botto, Alberto; Acuña, Julia; Jiménez, Juan Pablo

    2014-10-01

    Depression has a high impact on mental health. However its diagnosis is a challenge even for specialists. This problem derives from a failure in an adequate description and differentiation of the disease. This inadequate conceptualization generates these difficulties. Our thesis is that depression should be understood as a complex phenomenon that can be analyzed from multiple perspectives, from genes to behavior, including personality and interaction with the sociocultural environment. The aim of this paper is to review the psychopathological construct of depression from a multidimensional point of view, considering clinical, sociocultural, characterological and pathogenic variables. Finally we provide a proposal for an adequate diagnostic approach. PMID:25601115

  13. An epidemiological approach to depression prevention in old age

    Microsoft Academic Search

    F Smit; Niels Smits; Robert Schoevers; Dorly Deeg; Aartjan Beekman; Pim Cuijpers

    2008-01-01

    Objective: To identify target groups for prevention of chronic or recurrent depression\\u000ain old age such that prevention is likely to become cost-effective. Methods: Data were\\u000aused from a population-based cohort study (N 2,200). Chronic or recurrent\\u000adepression was defined when people presented with clinically high levels of depression\\u000aat two time points separated by 3 years. Risk profiles of

  14. Screening for postpartum depression in an inner-city population

    Microsoft Academic Search

    Jeanine K. Morris-Rush; Margaret Comerford Freda; Peter S. Bernstein

    2003-01-01

    Objective: This study was undertaken to determine the prevalence of positive screens for postpartum depression by using the Edinburgh Postnatal Depression Scale (EPDS) in an inner-city population. Study Design: At their postpartum visits, women who were seen in two inner-city practices between February 20 and April 30, 2002, self-administered the EPDS. A threshold of 10 or more points was selected

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

    PubMed

    Knopf, Daniel A; Alpert, Peter A

    2013-01-01

    Immersion freezing of water and aqueous solutions by particles acting as ice nuclei (IN) is a common process of heterogeneous ice nucleation which occurs in many environments, especially in the atmosphere where it results in the glaciation of clouds. Here we experimentally show, using a variety of IN types suspended in various aqueous solutions, that immersion freezing temperatures and kinetics can be described solely by temperature, T, and solution water activity, a(w), which is the ratio of the vapour pressure of the solution and the saturation water vapour pressure under the same conditions and, in equilibrium, equivalent to relative humidity (RH). This allows the freezing point and corresponding heterogeneous ice nucleation rate coefficient, J(het), to be uniquely expressed by T and a(w), a result we term the a(w) based immersion freezing model (ABIFM). This method is independent of the nature of the solute and accounts for several varying parameters, including cooling rate and IN surface area, while providing a holistic description of immersion freezing and allowing prediction of freezing temperatures, J(het), frozen fractions, ice particle production rates and numbers. Our findings are based on experimental freezing data collected for various IN surface areas, A, and cooling rates, r, of droplets variously containing marine biogenic material, two soil humic acids, four mineral dusts, and one organic monolayer acting as IN. For all investigated IN types we demonstrate that droplet freezing temperatures increase as A increases. Similarly, droplet freezing temperatures increase as the cooling rate decreases. The log10(J(het)) values for the various IN types derived exclusively by Tand a(w), provide a complete description of the heterogeneous ice nucleation kinetics. Thus, the ABIFM can be applied over the entire range of T, RH, total particulate surface area, and cloud activation timescales typical of atmospheric conditions. Lastly, we demonstrate that ABIFM can be used to derive frozen fractions of droplets and ice particle production for atmospheric models of cirrus and mixed phase cloud conditions. PMID:24601020

  16. Studies on Freezing RAM Semen in Absence of Glycerol.

    NASA Astrophysics Data System (ADS)

    Abdelnaby, Abdelhady Abdelhakeam

    1988-12-01

    Glycerol is widely used as a major cryoprotective agent for freezing spermatozoa of almost all species. However, it reduces fertility of sheep inseminated cervically compared with intrauterine insemination. Studies were conducted to develop a method and procedure for freezing ram semen in the absence of glycerol. Post -thaw survival of ram spermatozoa frozen in the absence of glycerol was affected by time and temperature after collection and before dilution and time after dilution and before freezing. Increase in time at 5^ circC before or after dilution and before freezing increased both post-thaw motility and number of cells passing through Sephadex filter. A cold dilution method was developed. Slow cooling of fresh ram semen and diluting at 5^circ C 2-3 hr. after collection, then freezing 1 hr. after dilution improved both post-thaw motility and number of cells passing through Sephadex filter compared with immediate dilution at 30-37^circC after collection and freezing 3-4 hr. later (P < 0.05). An extender was developed to freeze ram semen in the absence of glycerol. An increase in post-thaw motility was obtained when semen was extended in TES titrated with Tris to pH 7.0 (TEST) and osmotic pressure of 375-400 mOsm/kg, containing 25-30% (v/v) egg yolk and 10% (v/v) maltose. A special device (boat) for freezing was constructed to insure the same height of the sample above LN _2 and thus the same freezing rate from freeze to freeze. Freezing of semen in 0.25cc straws at 5-10 cm above LN_2 (73.8 to 49.5 ^circC/min) yielded higher post-thaw motility than the rates resulted from freezing at 15 cm above LN_2 or 1 cm above LN _2. Faster Thawing in 37^ circC water for 30 sec. (7.8^ circC/sec.) increased post-thaw motility compared with slower thawing in 5 or 20^circ C water (P < 0.05). A lambing rate of 52.2% was obtained in one fertility trial conducted with ram semen frozen without glycerol and 17.1% in a second trial. One injection (IM) of 15 mg PGF_{2alpha}/ewe for estrus synchronization during breeding season resulted in higher heat response and lambing rate than two injections given 10 days apart.

  17. [Depression--gender differences].

    PubMed

    Garde, Karin

    2007-06-18

    Unipolar depression is twice as frequent among women in fertile years compared to men. Current biological theories are that stages of life with declining levels of oestrogen could be a trigger of depression. Psychological theories are low self-esteem, sensitivity to lack of social support, comorbidity with anxiety, aggression turned inwards in women, outwards in men, whose comorbidity is alcohol abuse. Social theories are the preponderance of women in poverty and economic dependence. Symptoms and outcome are equal for men and women. Suicide is a greater risk for men, and increases with age; suicide attempts are a greater risk for women, and decline with age. During life span the rates of depression and anxiety and gender differences decline. PMID:17594834

  18. NEGATIVE SYMPTOMS IN DEPRESSION

    PubMed Central

    Chaturvedi, Santosh K.; Sarmukaddam, Sanjeev

    1985-01-01

    SUMMARY Negative symptoms have been assessed in 34 cases of major depression (ROC) using the scale for assessment of negative symptoms. Negative symptoms were found to be quite frequently observed in these cases; common negative symptoms were inability to enjoy recreational interests and activities (76%), feelings of anhedonia (64.7%) and physical anergia (55.9%). Poverty of speech was found to be more in younger patients (P < .001). Avolition was seen more frequently in unmarried (P < .05) patients. No other signiticant correlation was noticed between demographic variables and negative symptoms. The implications of evaluating negative symptoms systematically in depressives are for future research especially for prognostication, treatment responses and classification of depression based on such symptoms. PMID:21927088

  19. It's My Life: Depression

    NSDL National Science Digital Library

    2002-01-01

    It's My Life, a PBS Kids Web-based educational series, offers 9-12 year olds a kid-friendly way to explore and share the issues in their lives. Depression is just one of many subjects addressed in It's My Life. Topics covered in this Web site include defining depression, recognizing the symptoms, understanding the causes, getting treatment, how to help a friend or parent who may be suffering from depression, and more. In addition to articles on these topics, the Web site provides interactive activities -- such as a quiz and a chat room -- that help kids further their understanding of the disease and reach out for help if needed. Offline activities include a printable journal page, a recommended reading list, and discussion questions that kids can take to a parent or friend.

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

    PubMed

    Borgomaneri, Sara; Vitale, Francesca; Gazzola, Valeria; Avenanti, Alessio

    2015-04-01

    Fearful body language is a salient signal alerting the observer to the presence of a potential threat in the surrounding environment. Although detecting potential threats may trigger an immediate reduction of motor output in animals (i.e., freezing behavior), it is unclear at what point in time similar reductions occur in the human motor cortex and whether they originate from excitatory or inhibitory processes. Using single-pulse and paired-pulse transcranial magnetic stimulation (TMS), here we tested the hypothesis that the observer's motor cortex implements extremely fast suppression of motor readiness when seeing emotional bodies - and fearful body expressions in particular. Participants observed pictures of body postures and categorized them as happy, fearful or neutral while receiving TMS over the right or left motor cortex at 100-125msec after picture onset. In three different sessions, we assessed corticospinal excitability, short intracortical inhibition (SICI) and intracortical facilitation (ICF). Independently of the stimulated hemisphere and the time of the stimulation, watching fearful bodies suppressed ICF relative to happy and neutral body expressions. Moreover, happy expressions reduced ICF relative to neutral actions. No changes in corticospinal excitability or SICI were found during the task. These findings show extremely rapid bilateral modulation of the motor cortices when seeing emotional bodies, with stronger suppression of motor readiness when seeing fearful bodies. Our results provide neurophysiological support for the evolutionary notions that emotion perception is inherently linked to action systems and that fear-related cues induce an urgent mobilization of motor reactions. PMID:25835523

  1. Incorporation of ( sup 14 C)-palmitate into lipids of Brassica cells during the induction of freezing tolerance

    SciTech Connect

    Lynch, D.V.; Joseph, R.A. (Cornell Univ., Ithaca, NY (USA))

    1989-04-01

    Changes in plasma membrane lipid composition have been causally related to increased freezing tolerance. Studies of lipid metabolism during ABA induction of freezing tolerance in Brassica napus suspension cultures were undertaken. Cells were labeled with ({sup 14}C)-palmitate four days after transfer to fresh medium (control) or medium containing ABA (which increases freezing tolerance). At times between one and 20 hrs after labeling, ABA-treated cells incorporated almost twice the amount of label as controls cells. Approximately 80% of the radioactivity was associated with neutral lipids in ABA-treated cells and controls. Incorporation of label into total cellular polar lipids was 4.9 {times} 10{sup 5} dpm/mg protein for control cells and 1 {times} 10{sup 6} dpm/mg protein for cells transferred to medium containing ABA. Analysis of lipids following alkaline hydrolysis indicated that incorporation of ({sup 14}C)-palmitate into glucosylceramide of ABA-treated cells was less than 60% of control values when expressed relative to that of the total polar lipids. Incorporation into ceramides was also depressed in ABA-treated cells.

  2. The Vascular Depression Hypothesis: Mechanisms Linking Vascular Disease with Depression

    PubMed Central

    Taylor, Warren D.; Aizenstein, Howard J.; Alexopoulos, George S.

    2013-01-01

    The ‘Vascular Depression’ hypothesis posits that cerebrovascular disease may predispose, precipitate, or perpetuate some geriatric depressive syndromes. This hypothesis stimulated much research that has improved our understanding of the complex relationships between late-life depression (LLD), vascular risk factors, and cognition. Succinctly, there are well-established relationships between late-life depression, vascular risk factors, and cerebral hyperintensities, the radiological hallmark of vascular depression. Cognitive dysfunction is common in late-life depression, particularly executive dysfunction, a finding predictive of poor antidepressant response. Over time, progression of hyperintensities and cognitive deficits predicts a poor course of depression and may reflect underlying worsening of vascular disease. This work laid the foundation for examining the mechanisms by which vascular disease influences brain circuits and influences the development and course of depression. We review data testing the vascular depression hypothesis with a focus on identifying potential underlying vascular mechanisms. We propose a disconnection hypothesis, wherein focal vascular damage and white matter lesion location is a crucial factor influencing neural connectivity that contributes to clinical symptomatology. We also propose inflammatory and hypoperfusion hypotheses, concepts that link underlying vascular processes with adverse effects on brain function that influence the development of depression. Testing such hypotheses will not only inform the relationship between vascular disease and depression but also provide guidance on the potential repurposing of pharmacological agents that may improve late-life depression outcomes. PMID:23439482

  3. [Biological rhythms and depression].

    PubMed

    Wirz-Justice, A

    1986-01-01

    Circadian rhythms are found in all living organisms, and represent a physiological correlate of the geophysical rhythm of day and night. These rhythms are endogenous in nature, driven by a pacemaker in the hypothalamus, and synchronized to the 24-hour day. Many of the symptoms of affective illness can be considered in terms of altered timing of circadian rhythms. Furthermore, total or partial sleep deprivation or phase advance of the sleep-wake cycle can induce remission (albeit temporary) in many depressive patients, and antidepressant drugs influence circadian rhythm characteristics. Bright light may have antidepressant properties in certain seasonally recurring depressives. PMID:2431475

  4. Relationship between freezing tolerance and shoot water relations of western red cedar.

    PubMed

    Grossnickle, S C

    1992-10-01

    Freezing tolerance and shoot water relations parameters of western red cedar (Thuja plicata Donn) seedlings were measured every 2 weeks from October 1989 to April 1990. Freezing tolerance, measured by freeze-induced electrolyte leakage, showed seasonal shifts in the temperature causing 50% foliage electrolyte leakage (LT(50)). The LT(50) value was -4 degrees C in October, it decreased to -20 degrees C in February and then increased to -6 degrees C in April. The foliage index of injury at -10 degrees C (II(-10)) also showed seasonal shifts from a high of 98% in October to a low of 18% in February followed by an increase to 82% in April. Osmotic potentials at saturation (Psi(s(sat))) and turgor loss point (Psi(s(tlp))) were, respectively, -1.07 and -1.26 MPa in October, -1.57 and -2.43 MPa in January, and -1.04 and -1.86 MPa in April. Dry weight fraction (DWF) increased and symplastic volume at full turgor (V(o)) decreased during the fall-winter acclimation phase, whereas DWF decreased and V(o) increased during the late winter-spring deacclimation phase. Relationships between seasonal patterns of freezing tolerance and shoot water relations parameters showed that LT(50) and II(-10) decreased linearly as Psi(s(tlp)) and V(o) decreased and DWF increased. There was no discernible difference in the relationship during fall acclimation or spring deacclimation. The freezing dehydration index at -10 degrees C (FDI(-10)) declined from 0.69 in November to 0.41 in February and increased to 0.56 in April. The value of II(-10) decreased linearly as FDI(-10) decreased, although a measurement made on actively growing spring foliage did not fit this relationship. The results indicate that seasonal changes in freezing tolerance of western red cedar are partially due to changes in tissue water content, symplastic volume, passive osmotic adjustment and FDI(-10). PMID:14969948

  5. Heterogeneous freezing of droplets with immersed mineral dust particles - measurements and parameterization

    NASA Astrophysics Data System (ADS)

    Niedermeier, D.; Hartmann, S.; Shaw, R. A.; Covert, D.; Mentel, T. F.; Schneider, J.; Poulain, L.; Reitz, P.; Spindler, C.; Clauss, T.; Kiselev, A.; Hallbauer, E.; Wex, H.; Mildenberger, K.; Stratmann, F.

    2010-04-01

    During the measurement campaign FROST (FReezing Of duST), LACIS (Leipzig Aerosol Cloud Interaction Simulator) was used to investigate the immersion freezing behavior of size selected, coated and uncoated Arizona Test Dust (ATD) particles with a mobility diameter of 300 nm. Particles were coated with succinic acid (C4H6O4), sulfuric acid (H2SO4) and ammonium sulfate ((NH4)2SO4). Ice fractions at mixed-phase cloud temperatures ranging from 233.15 K to 239.15 K (±0.60 K) were determined for all types of particles. In this temperature range, pure ATD particles and those coated with C4H6O4 or small amounts of H2SO4 were found to be the most efficient ice nuclei (IN). ATD particles coated with (NH4)2SO4 were the most inefficient IN. Since the supercooled droplets were highly diluted before freezing occurred, a freezing point suppression due to the soluble material on the particles (and therefore in the droplets) cannot explain this observation. Therefore, it is reasonable to assume that the coatings lead to particle surface alterations which cause the differences in the IN abilities. Two different theoretical approaches based on the stochastic and the singular hypotheses were applied to clarify and parameterize the freezing behavior of the particles investigated. Both approaches describe the experimentally determined results, yielding parameters that can subsequently be used to compare our results to those from other studies. However, we cannot clarify at the current state which of the two approaches correctly describes the investigated immersion freezing process. But both approaches confirm the assumption that the coatings lead to particle surface modifications lowering the nucleation efficiency. The stochastic approach interprets the reduction in nucleation rate from coating as primarily due to an increase in the thermodynamic barrier for ice formation (i.e., changes in interfacial free energies). The singular approach interprets the reduction as resulting from a reduced surface density of active sites.

  6. Freeze-Thaw Durability of Air-Entrained Concrete

    PubMed Central

    Shang, Huai-Shuai; Yi, Ting-Hua

    2013-01-01

    One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles). The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss) and internal crack growth (characterized by the loss of dynamic modulus of elasticity). The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. The experimental study of C20, C25, C30, C40, and C50 air-entrained concrete specimens was completed according to “the test method of long-term and durability on ordinary concrete” GB/T 50082-2009. The dynamic modulus of elasticity and weight loss of specimens were measured after different cycles of freeze-thaw. The influence of freeze-thaw cycles on the relative dynamic modulus of elasticity and weight loss was analyzed. The findings showed that the dynamic modulus of elasticity and weight decreased as the freeze-thaw cycles were repeated. They revealed that the C30, C40, and C50 air-entrained concrete was still durable after 300 cycles of freeze-thaw according to the experimental results. PMID:23576906

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

    PubMed

    Shang, Huai-Shuai; Yi, Ting-Hua

    2013-01-01

    One of the most damaging actions affecting concrete is the abrupt temperature change (freeze-thaw cycles). The types of deterioration of concrete structures by cyclic freeze-thaw can be largely classified into surface scaling (characterized by the weight loss) and internal crack growth (characterized by the loss of dynamic modulus of elasticity). The present study explored the durability of concrete made with air-entraining agent subjected to 0, 100, 200, 300, and 400 cycles of freeze-thaw. The experimental study of C20, C25, C30, C40, and C50 air-entrained concrete specimens was completed according to "the test method of long-term and durability on ordinary concrete" GB/T 50082-2009. The dynamic modulus of elasticity and weight loss of specimens were measured after different cycles of freeze-thaw. The influence of freeze-thaw cycles on the relative dynamic modulus of elasticity and weight loss was analyzed. The findings showed that the dynamic modulus of elasticity and weight decreased as the freeze-thaw cycles were repeated. They revealed that the C30, C40, and C50 air-entrained concrete was still durable after 300 cycles of freeze-thaw according to the experimental results. PMID:23576906

  8. Levodopa changes the severity of freezing in Parkinson's disease.

    PubMed

    Fietzek, Urban M; Zwosta, Jens; Schroeteler, Frauke E; Ziegler, Kerstin; Ceballos-Baumann, Andres O

    2013-10-01

    Oral levodopa has been proposed to be one of the more effective medications to alleviate freezing of gait, but there is limited data on its efficacy. We evaluated the gait phenomenology of 20 Parkinson's disease patients with freezing of gait before and 60 min after a standardized levodopa dose using a rating scale based on the assumption that festination and akinetic freezing share a common pathophysiology. Levodopa abolished festination and freezing in 20% of patients (p < 0.0001), and reduced the freezing sum score from a median of 15 (IQR 6.75-27.5) to 3.5 (1-11.25), p < 0.001) in all but one of the remainder. Pre-dose ratings correlated with post-dose ratings, in that those patients with lower pre-dose item-scores also showed lower post-dose outcome scores. Levodopa's effect on both festination and akinetic freezing was linear, thereby supporting the concept that festination and freezing are variants on a continuity of episodic gait disorders in PD. PMID:23642712

  9. Metabolic Changes in Avena sativa Crowns Recovering from Freezing

    PubMed Central

    Henson, Cynthia A.; Duke, Stanley H.; Livingston, David P.

    2014-01-01

    Extensive research has been conducted on cold acclimation and freezing tolerance of fall-sown cereal plants due to their economic importance; however, little has been reported on the biochemical changes occurring over time after the freezing conditions are replaced by conditions favorable for recovery and growth such as would occur during spring. In this study, GC-MS was used to detect metabolic changes in the overwintering crown tissue of oat (Avena sativa L.) during a fourteen day time-course after freezing. Metabolomic analysis revealed increases in most amino acids, particularly proline, 5-oxoproline and arginine, which increased greatly in crowns that were frozen compared to controls and correlated very significantly with days after freezing. In contrast, sugar and sugar related metabolites were little changed by freezing, except sucrose and fructose which decreased dramatically. In frozen tissue all TCA cycle metabolites, especially citrate and malate, decreased in relation to unfrozen tissue. Alterations in some amino acid pools after freezing were similar to those observed in cold acclimation whereas most changes in sugar pools after freezing were not. These similarities and differences suggest that there are common as well as unique genetic mechanisms between these two environmental conditions that are crucial to the winter survival of plants. PMID:24675792

  10. Depression and Bipolar Support Alliance

    MedlinePLUS

    ... events Visit the podcast archive Mood Disorders Depression Bipolar Disorder Anxiety Screening Center Co-occurring Illnesses/Disorders ... for Your Patients Information about Depression Information about Bipolar Disorder Wellness Tools DBSA Support Groups Active Research ...

  11. Depression and High School Students

    MedlinePLUS

    ... Autism (1 Item) Bipolar Disorder (5 Items) Borderline Personality Disorder (1 Item) Depression (19 Items) Eating Disorders (1 ... Autism (1 Item) Bipolar Disorder (5 Items) Borderline Personality Disorder (1 Item) Depression (19 Items) Eating Disorders (1 ...

  12. Beating Depression …Help Is Available

    MedlinePLUS

    ... Navigation Bar Home Current Issue Past Issues Beating Depression …Help Is Available Past Issues / Summer 2007 Table ... treatments are available from your physician. Types of Depression Just like other illnesses, such as heart disease, ...

  13. Depression and HIV/AIDS

    MedlinePLUS

    ... see the NIMH booklet on Depression . What is HIV/AIDS? Human immunodeficiency virus (HIV) is the virus ... they can function normally. How are depression and HIV/AIDS linked? Studies show that people who are ...

  14. The Paranoid-Depressive Continuum

    ERIC Educational Resources Information Center

    Johnson, Betty J.

    1977-01-01

    Few investigators have attempted to lay a conceptual base for comparative studies of paranoia and depression within a single general framework. The paranoid-depressive continuum is an attempt to develop such a framework. (Author)

  15. Postpartum Depression: An Interactional View.

    ERIC Educational Resources Information Center

    Kraus, Mary Ann; Redman, E. Scott

    1986-01-01

    Postpartum depression is conceptualized as a predictable developmental, family crisis, which occurs when the natural difficulties of childbirth are benignly mishandled. Tactics are illustrated for interdicting maladaptive interpersonal spirals, including normalizing conflicting complaints; reframing depression as positive but costly; regulating…

  16. Immersion freezing on mineral dust particles

    NASA Astrophysics Data System (ADS)

    Zolles, Tobias; Grothe, Hinrich; Pummer, Bernhard

    2013-04-01

    Mineral dust is considered to play a major role in ice cloud nucleation in the troposphere. More than 1.000 Tg of mineral dust are aerosolized from the ground every year, 1-10% of these reach the upper troposphere [1]. At an altitude of about 8 km ice residual particle analysis has shown that about 50% of all ice nuclei (IN) are mineral dust[2]. In principle, natural occurring dusts may either be IN-active themselves or are carriers of organic and/or biological IN. Up to now the ice nucleation, i.e. cloud glaciation, has not been quantized. However, different authors report a high IN-activity for many mineral dust samples, although a systematic comparison between different minerals is still missing. Therefore, we studied selected mineral dust samples which were characterized by X-ray diffraction, FTIR spectroscopy, and scanning electron microscopy before use. Oil immersion measurements were performed on the most common minerals, clay materials and volcanic ash. The median freezing temperatures range from -21°C up to homogenous freezing at 38°C. Even though quite a few dust samples show a reasonable high IN-activity, their median freezing temperatures are low compared to biological samples [3, 4]. Furthermore, heat treatment of the dusts was applied in order to decompose and to denaturize organic and/or biological surfactants. Finally, some dust samples had a high loss of activity and thus were subjects of further experiments. These mineral dust particles were suspended in water and after an incubation time were removed. In some cases the washing water had become IN-active, but lost its activity after enzymatic treatment. The observed high IN-activity can thus be explained by adsorbed biological materials. The results suggest that some mineral dusts are IN-active, and if it is not intrinsic they may even enhance IN-activity of organic and biological IN if these are adsorbed on the dust particle surface. A relatively high IN-activity of the pure mineral dusts was only observed in quartz, clays, and mixed natural dusts (ATD), which are mainly composed of SiO2 and clays. References. [1] C. S. Zender, R. L. Miller and I. Tegen, Eos Trans. AGU, 2004,85, 509. [2] K. A. Pratt, P. J. DeMott, J. R. French, Z. Wang, D. L. Westphal, A. J. Heymsfield, C. H. Twohy, A. J. Prenni, K. A. Prather, Nat. Geosci., 2009, 2, 397-400. [3] B. Pummer, H. Bauer, J. Bernardi, S. Bleicher and H. Grothe, Atmos. Chem. Phys., 2012, 12, 2541-2550. [4] V. T. J. Phillips, C. Andronache, B. Christner, C. E. Morris, D. C. Sands, A. Bansemer, A. Lauer, C. McNaughton and C. Seman, Biogeosciences, 2009, 6, 987-1014.

  17. Air-Cooled Stack Freeze Tolerance Freeze Failure Modes and Freeze Tolerance Strategies for GenDriveTM Material Handling Application Systems and Stacks Final Scientific Report

    SciTech Connect

    Hancock, David, W.

    2012-02-14

    Air-cooled stack technology offers the potential for a simpler system architecture (versus liquid-cooled) for applications below 4 kilowatts. The combined cooling and cathode air allows for a reduction in part count and hence a lower cost solution. However, efficient heat rejection challenges escalate as power and ambient temperature increase. For applications in ambient temperatures below freezing, the air-cooled approach has additional challenges associated with not overcooling the fuel cell stack. The focus of this project was freeze tolerance while maintaining all other stack and system requirements. Through this project, Plug Power advanced the state of the art in technology for air-cooled PEM fuel cell stacks and related GenDrive material handling application fuel cell systems. This was accomplished through a collaborative work plan to improve freeze tolerance and mitigate freeze-thaw effect failure modes within innovative material handling equipment fuel cell systems designed for use in freezer forklift applications. Freeze tolerance remains an area where additional research and understanding can help fuel cells to become commercially viable. This project evaluated both stack level and system level solutions to improve fuel cell stack freeze tolerance. At this time, the most cost effective solutions are at the system level. The freeze mitigation strategies developed over the course of this project could be used to drive fuel cell commercialization. The fuel cell system studied in this project was Plug Power's commercially available GenDrive platform providing battery replacement for equipment in the material handling industry. The fuel cell stacks were Ballard's commercially available FCvelocity 9SSL (9SSL) liquid-cooled PEM fuel cell stack and FCvelocity 1020ACS (Mk1020) air-cooled PEM fuel cell stack.

  18. Systematics of kinetic freeze-out properties in high energy collisions from STAR

    NASA Astrophysics Data System (ADS)

    Kumar, Lokesh

    2014-11-01

    The main aim of the RHIC Beam Energy Scan (BES) program is to explore the QCD phase diagram which includes search for a possible QCD critical point and the phase boundary between QGP and hadronic phase. We report the collision energy and centrality dependence of kinetic freeze-out properties from the measured mid-rapidity (| y | < 0.1) light hadrons (pions, kaons, protons and their anti-particles) for Au + Au collisions at the center-of-mass energy ?{sNN} = 7.7 , 11.5 , 19.6 , 27 , and 39 GeV. The STAR detector, with a large uniform acceptance and excellent particle identification is used in the data collection and analysis. The kinetic freeze-out temperature Tkin and average collective velocity < ? > parameters are extracted from blast-wave fits to the identified hadron spectra and systematically compared with the results from other collision energies including those at AGS, SPS and LHC. It is found that all results fall into an anti-correlation band in the 2-dimensional (Tkin, < ? >) distribution: the largest value of collective velocity and lowest temperature is reached in the most central collisions at the highest collision energy. The energy dependence of these freeze-out parameters is discussed.

  19. Exploring Human Freeze Responses to a Threat Stressor

    PubMed Central

    Schmidt, Norman B.; Richey, J. Anthony; Zvolensky, Michael J.; Maner, Jon K.

    2008-01-01

    Despite the fundamental nature of tonic immobility in anxiety responses, surprisingly little empirical research has focused on the “freeze” response in humans. The present report evaluated frequency and predictors of a freeze response in the context of a biological challenge. A nonclinical sample (N = 404) underwent a 20-sec inhalation of 20% CO2/balance O2. Perceptions of immobility in the context of the challenge were reported in 13% of the sample, compared to 20% reporting a significant desire to flee. Subjective anxiety and panic during the challenge were associated with the freeze response, as were a number of anxiety symptom dimensions. PMID:17880916

  20. Freeze Tape Casting of Functionally Graded Porous Ceramics

    NASA Technical Reports Server (NTRS)

    Sofie, Stephen W.

    2007-01-01

    Freeze tape casting is a means of making preforms of ceramic sheets that, upon subsequent completion of fabrication processing, can have anisotropic and/or functionally graded properties that notably include aligned and graded porosity. Freeze tape casting was developed to enable optimization of the microstructures of porous ceramic components for use as solid oxide electrodes in fuel cells: Through alignment and grading of pores, one can tailor surface areas and diffusion channels for flows of gas and liquid species involved in fuel-cell reactions. Freeze tape casting offers similar benefits for fabrication of optimally porous ceramics for use as catalysts, gas sensors, and filters.