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Sample records for antifreeze

  1. Saccharide antifreeze compositions

    Science.gov (United States)

    Walters, Kent; Duman, John G; Serianni, Anthony S

    2013-12-10

    The invention provides an antifreeze glycolipid compounds and composition comprising a polysaccharide moiety of Formula I; ##STR00001## wherein D-Manp represents a D-mannopyranose moiety, D-Xylp represents a D-xylopyranose moiety, and n is about 5 to about 70; and one or more lipid moieties covalently linked to the polysaccharide moiety of Formula I or electrostatically associated with the polysaccaride moiety for Formula I. The antifreeze glycolipid compounds and compositions can be used for a variety of industrial, agricultural, medical, and cosmetic applications where recrystallization-inhibition, cyroprotection, or cryopreservation is desired. The antifreeze glycolipid compounds or compositions can be used as, for example, as cryoprotectants for tissue preservation and transplantation, improving the texture of processed frozen food and frozen meats, frostbit protection, crop protection, and green alternatives for land vehicle antifreeze and aircraft de-icing.

  2. Antifreeze glycopeptide diastereomers

    Directory of Open Access Journals (Sweden)

    Lilly Nagel

    2012-10-01

    Full Text Available Antifreeze glycopeptides (AFGPs are a special class of biological antifreeze agents, which possess the property to inhibit ice growth in the body fluids of arctic and antarctic fish and, thus, enable life under these harsh conditions. AFGPs are composed of 4–55 tripeptide units -Ala-Ala-Thr- glycosylated at the threonine side chains. Despite the structural homology among all the fish species, divergence regarding the composition of the amino acids occurs in peptides from natural sources. Although AFGPs were discovered in the early 1960s, the adsorption mechanism of these macromolecules to the surface of the ice crystals has not yet been fully elucidated. Two AFGP diastereomers containing different amino acid configurations were synthesized to study the influence of amino acid stereochemistry on conformation and antifreeze activity. For this purpose, peptides containing monosaccharide-substituted allo-L- and D-threonine building blocks were assembled by solid-phase peptide synthesis (SPPS. The retro-inverso AFGP analogue contained all amino acids in D-configuration, while the allo-L-diastereomer was composed of L-amino acids, like native AFGPs, with replacement of L-threonine by its allo-L-diastereomer. Both glycopeptides were analyzed regarding their conformational properties, by circular dichroism (CD, and their ability to inhibit ice recrystallization in microphysical experiments.

  3. Antifreeze life cycle assessment (LCA

    Directory of Open Access Journals (Sweden)

    Kesić Jelena

    2005-01-01

    Full Text Available Antifreeze based on ethylene glycol is a commonly used commercial product The classification of ethylene glycol as a toxic material increased the disposal costs for used antifreeze and life cycle assessment became a necessity. Life Cycle Assessment (LCA considers the identification and quantification of raw materials and energy inputs and waste outputs during the whole life cycle of the analyzed product. The objectives of LCA are the evaluation of impacts on the environment and improvements of processes in order to reduce and/or eliminate waste. LCA is conducted through a mathematical model derived from mass and energy balances of all the processes included in the life cycle. In all energy processes the part of energy that can be transformed into some other kind of energy is called exergy. The concept of exergy considers the quality of different types of energy and the quality of different materials. It is also a connection between energy and mass transformations. The whole life cycle can be described by the value of the total loss of exergy. The physical meaning of this value is the loss of material and energy that can be used. The results of LCA are very useful for the analyzed products and processes and for the determined conditions under which the analysis was conducted. The results of this study indicate that recycling is the most satisfactory solution for the treatment of used antifreeze regarding material and energy consumption but the re-use of antifreeze should not be neglected as a solution.

  4. Plant Antifreeze Proteins and Their Expression Regulatory Mechanism

    Institute of Scientific and Technical Information of China (English)

    Lin Yuan-zhen; Lin Shan-zhi; Zhang Zhi-yi; Zhang Wei; Liu Wen-feng

    2005-01-01

    Low temperature is one of the major limiting environmental factors which constitutes the growth, development,productivity and distribution of plants. Over the past several years, the proteins and genes associated with freezing resistance of plants have been widely studied. The recent progress of domestic and foreign research on plant antifreeze proteins and the identification and characterization of plant antifreeze protein genes, especially on expression regulatory mechanism of plant antifreeze proteins are reviewed in this paper. Finally, some unsolved problems and the trend of research in physiological functions and gene expression regulatory mechanism of plant antifreeze proteins are discussed.

  5. Antivirulence Properties of an Antifreeze Protein

    Directory of Open Access Journals (Sweden)

    Martin Heisig

    2014-10-01

    Full Text Available As microbial drug-resistance increases, there is a critical need for new classes of compounds to combat infectious diseases. The Ixodes scapularis tick antifreeze glycoprotein, IAFGP, functions as an antivirulence agent against diverse bacteria, including methicillin-resistant Staphylococcus aureus. Recombinant IAFGP and a peptide, P1, derived from this protein bind to microbes and alter biofilm formation. Transgenic iafgp-expressing flies and mice challenged with bacteria, as well as wild-type animals administered P1, were resistant to infection, septic shock, or biofilm development on implanted catheter tubing. These data show that an antifreeze protein facilitates host control of bacterial infections and suggest therapeutic strategies for countering pathogens.

  6. Coarse grained simulation reveals antifreeze properties of hyperactive antifreeze protein from Antarctic bacterium Colwellia sp.

    Science.gov (United States)

    Nguyen, Hung; Van, Thanh Dac; Le, Ly

    2015-10-01

    The novel hyperactive antifreeze protein (AFP) of Antarctic sea ice bacterium Colwellia sp. provides a target for studying the protection of psychrophilic microgoranisms against freezing environment. Interestingly, the Colwellia sp. hyperactive antifreeze protein (ColAFP) was crystallized without the structural dynamic characteristics. Here, the result indicated, through coarse grained simulation of ColAFP under various subfreezing temperature, that ColAFP remains active at temperature of equal and greater than 275 K (∼2 °C). Extensive simulation analyses also revealed the adaptive mechanism of ColAFP in subfreezing environment. Our result provides a structural dynamic understanding of the ColAFP.

  7. Antifreeze activity enhancement by site directed mutagenesis on an antifreeze protein from the beetle Rhagium mordax.

    Science.gov (United States)

    Friis, Dennis Steven; Kristiansen, Erlend; von Solms, Nicolas; Ramløv, Hans

    2014-05-01

    The ice binding motifs of insect antifreeze proteins (AFPs) mainly consist of repetitive TxT motifs aligned on a flat face of the protein. However, these motifs often contain non-threonines that disrupt the TxT pattern. We substituted two such disruptive amino acids located in the ice binding face of an AFP from Rhagium mordax with threonine. Furthermore, a mutant with an extra ice facing TxT motif was constructed. These mutants showed enhanced antifreeze activity compared to the wild type at low concentrations. However, extrapolating the data indicates that the wild type will become the most active at concentrations above 270 μmol.

  8. Protein-water dynamics in antifreeze protein III activity

    Science.gov (United States)

    Xu, Yao; Bäumer, Alexander; Meister, Konrad; Bischak, Connor G.; DeVries, Arthur L.; Leitner, David M.; Havenith, Martina

    2016-03-01

    We combine Terahertz absorption spectroscopy (THz) and molecular dynamics (MD) simulations to investigate the underlying molecular mechanism for the antifreeze activity of one class of antifreeze protein, antifreeze protein type III (AFP-III) with a focus on the collective water hydrogen bond dynamics near the protein. After summarizing our previous work on AFPs, we present a new investigation of the effects of cosolutes on protein antifreeze activity by adding sodium citrate to the protein solution of AFP-III. Our results reveal that for AFP-III, unlike some other AFPs, the addition of the osmolyte sodium citrate does not affect the hydrogen bond dynamics at the protein surface significantly, as indicated by concentration dependent THz measurements. The present data, in combination with our previous THz measurements and molecular simulations, confirm that while long-range solvent perturbation is a necessary condition for the antifreeze activity of AFP-III, the local binding affinity determines the size of the hysteresis.

  9. Antifreeze activity enhancement by site directed mutagenesis on an antifreeze protein from the beetle Rhagium mordax

    DEFF Research Database (Denmark)

    Friis, Dennis Steven; Kristiansen, Erlend; von Solms, Nicolas;

    2014-01-01

    of an AFP from Rhagium mordax with threonine. Furthermore, a mutant with an extra ice facing TxT motif was constructed. These mutants showed enhanced antifreeze activity compared to the wild type at low concentrations. However, extrapolating the data indicates that the wild type will become the most active...

  10. Antifreeze proteins enable plants to survive in freezing conditions

    Indian Academy of Sciences (India)

    Ravi Gupta; Renu Deswal

    2014-12-01

    Overwintering plants secrete antifreeze proteins (AFPs) to provide freezing tolerance. These proteins bind to and inhibit the growth of ice crystals that are formed in the apoplast during subzero temperatures. Antifreeze activity has been detected in more than 60 plants and AFPs have been purified from 15 of these, including gymnosperms, dicots and monocots. Biochemical characterization of plant antifreeze activity, as determined by the high ice recrystallization inhibition (IRI) activities and low thermal hysteresis (TH) of AFPs, showed that their main function is inhibition of ice crystal growth rather than the lowering of freezing temperatures. However, recent studies showed that antifreeze activity with higher TH also exists in plants. Calcium and hormones like ethylene and jasmonic acid have been shown to regulate plant antifreeze activity. Recent studies have shown that plant AFPs bind to both prism planes and basal planes of ice crystals by means of two flat ice binding sites. Plant AFPs have been postulated to evolve from the OsLRR-PSR gene nearly 36 million years ago. In this review, we present the current scenario of plant AFP research in order to understand the possible potential of plant AFPs in generation of freezing-tolerant crops.

  11. Prediction of Antifreeze Critical Strength of Infant Age Concrete

    Institute of Scientific and Technical Information of China (English)

    LIU Jun; LIU Runqing

    2008-01-01

    The rule of infant age concrete strength development under low temperature and complex affecting factors is researched. An efficient and reliable mathematical forecast model is set up to predict the infant age concrete antifreeze critical strength under low temperature at construction site. On the basis of the revision of concrete equivalent coefficient under complex influencing factors, least-squares curve-fitting method is applied to approximate the concrete strength under standard curing and the forecast formula of concrete compressive strength could be obtained under natural temperature condition by various effects. When the amounts of donble-doped are 10% fly ashes and 4% silica fumes as cement replacement, the antifreeze critical strength changes form 3.5-4.1MPa under different low temperature curing. The equivalent coefficient correction formula of concrete under low temperature affected by various factors could be obtained. The obtainede quivalent coefficient is suitable for calculating the strength which is between 10% to 40% of standard strength and the curing temperature from 5-20 ℃. The forecast value of concrete antifreeze critical strength under low temperature could be achieved by combining the concrete antifreeze critical strength value with the compressive strength forecast of infant age concrete under low temperature. Then the theory for construction quality control under low temperature is provided.

  12. RAPID TEST METHOD FOR EVALUATION OF ANTIFREEZE ADDITIVE EFFICIENCY

    Directory of Open Access Journals (Sweden)

    S. V. Gushchin

    2015-01-01

    Full Text Available Usage of chemical additives while executing concrete works at negative temperatures is considered as a convenient and economical method. Range of the used antifreeze additives is rather wide. A great number of new additives are advertised but their characteristics have not been practically studied. Evaluation of the antifreeze additive efficiency is unfortunately rather long process and it does not provide comprehensive data on concrete structure formation processes. Due to this development of rapid and comprehensive methodology for construction companies is urgently required.Freezing processes of antifreeze additive aqueous solutions and hardening of cement paste with them have been investigated in the paper. The paper proposes a methodology for determination of freezing point for aqueous solutions of chemical additives of various applications. Identity of  freezing point for a chemical additive aqueous solution and cement paste with an equal concentration of the additive in the paste pore fluid has been determined while taking  calcium nitrate and sodium formate additives as an example. The paper demonstrates the possibility to evaluate efficiency of antifreeze additive action on the basis of kinetics in temperature changes of the cement paste with additives by its consecutive freezing and defrosting.  A methodology for operational evaluation in the field of chemical additive application for concreting items at negative temperatures has been offered in the paper.  The methodology does not require  deficient and expensive test-equipment. It can be applied at ordinary construction companies and it is comprehensible for personnel of low-qualification.  The paper shows the possibility to develop an original methodology for designing concrete structure which is based on operating efficiency determinations  for single and integrated antifreeze additives.

  13. Effect of Anti-freezing Admixtures on Alkali-silica Reaction in Mortars

    Institute of Scientific and Technical Information of China (English)

    LIU Junzhe; LI Yushun; LV Lihua

    2005-01-01

    The influence of anti-freezing admixture on the alkali aggregate reaction in mortar was analyzed with accelerated methods. It is confirmed that the addition of sodium salt ingredients of anti-freezing admixture accelerates the alkali silica reaction to some extent, whereas calcium salt ingredient of anti-freezing admixture reduces the expansion of alkali silica reaction caused by high alkali cement. It is found that the addition of the fly ash considerably suppresses the expansion of alkali silica reaction induced by the anti-freezing admixtures.

  14. Expression of a Carrot Antifreeze Protein Gene in Escherichia coli

    Institute of Scientific and Technical Information of China (English)

    Ma Xinyu; Shen Xin; Lu Cunfu

    2003-01-01

    The recombinant expression vectorpET43. lb-AFP, which contains full encoding region of a carrot 36 kD antifreeze protein (AFP) gene was constructed. The recombinant was transformed into expression host carrying T7 RNA polymerase gene (DE3 lysogen) and induced by 1 mmol. L-1 IPTG (isopropyl-β-D-thiogalactoside) to express 110 kD polypeptide of AFP fusion protein.The analysis of product solubility revealed that pET43. 1b-AFP was predominately soluble, and the expressed amount reached the maximum after the IPTG treatment for 3 h.

  15. Computational simulations on the fish-type-Ⅱ antifreeze protein-ice-solvent system

    Institute of Scientific and Technical Information of China (English)

    LIU Kai; WANG Yan; TAN Hongwei; CHEN Guangju; TONG Zhenhe

    2007-01-01

    Based on the computational simulation with the vacuum environment for the fish-type-Ⅱ antifreeze proteinice-solvent (water)system,the multi-complex system of the antifreeze protein-ice-water has been constructed and calculated.We have studied the interaction of such proteinice system with water solvent through the dynamics simulation with 350 ps.By employing the Molecular Dynamics simulation and semi-empirical method calculation,we have further investigated the interface properties of the antifreeze protein and ice crystal combined system.Consequently,a water solvent affects significantly the properties of this combined system.

  16. Dynamical mechanism of antifreeze proteins to prevent ice growth

    CERN Document Server

    Kutschan, B; Thoms, S

    2014-01-01

    The fascinating ability of algae, insects and fishes to survive at temperatures below normal freezing is realized by antifreeze proteins (AFPs). Antifreeze proteins (AFPs) are surface-active molecules and interact with the diffusive water/ice interface preventing a complete solidification. A new dynamical mechanism is proposed how these proteins inhibit the freezing of water. We apply a Ginzburg-Landau type approach to describe the phase separation in the two-component system (ice, AFP). The free energy density involves two fields: one for the ice phase with low AFP concentration, and one for the liquid water with high AFP concentration. The time evolution of the ice reveals microstructures as a result of phase separation in the presence of AFPs. We observe a faster clustering of pre-ice structure connected with a locking of grain size by the action of AFP which is an essentially dynamical process. The adsorption of additional water molecules are inhibited and the further growth of ice grains are stopped. The...

  17. Validation of antifreeze properties of glutathione based on its thermodynamic characteristics and protection of baker's yeast during cryopreservation.

    Science.gov (United States)

    Zhang, Chao; Zhang, Hui; Wang, Li; Yao, Huiyuan

    2007-06-13

    The antifreeze ability of glutathione was evaluated on the basis of its thermodynamic characteristics and protection of baker's yeast during cryopreservation at -30 degrees C. The thermodynamic characteristics and protection of baker's yeast of glutathione were similar to those of known antifreeze proteins, such as carrot antifreeze protein and holly antifreeze protein. These properties included lowering the freezing point at about 0.20 degrees C non-colligatively, decreasing freezable water content, controlling the movement of free water for its strong hydrophilicity, and improving baker's yeast survival during the simulated processing of frozen dough. Therefore, glutathione was viewed to be an antifreeze protein like substance on the basis of its unique thermodynamic characteristics and protection of baker's yeast. The method combining thermodynamic characteristic analysis and protection evaluation is a new and simple way to screen new antifreeze proteins. PMID:17508758

  18. Towards a green hydrate inhibitor: imaging antifreeze proteins on clathrates.

    Directory of Open Access Journals (Sweden)

    Raimond Gordienko

    Full Text Available The formation of hydrate plugs in oil and gas pipelines is a serious industrial problem and recently there has been an increased interest in the use of alternative hydrate inhibitors as substitutes for thermodynamic inhibitors like methanol. We show here that antifreeze proteins (AFPs possess the ability to modify structure II (sII tetrahydrofuran (THF hydrate crystal morphologies by adhering to the hydrate surface and inhibiting growth in a similar fashion to the kinetic inhibitor poly-N-vinylpyrrolidone (PVP. The effects of AFPs on the formation and growth rate of high-pressure sII gas mix hydrate demonstrated that AFPs are superior hydrate inhibitors compared to PVP. These results indicate that AFPs may be suitable for the study of new inhibitor systems and represent an important step towards the development of biologically-based hydrate inhibitors.

  19. Inhibition of Condensation Frosting by Arrays of Hygroscopic Antifreeze Drops.

    Science.gov (United States)

    Sun, Xiaoda; Damle, Viraj G; Uppal, Aastha; Linder, Rubin; Chandrashekar, Sriram; Mohan, Ajay R; Rykaczewski, Konrad

    2015-12-29

    The formation of frost and ice can have negative impacts on travel and a variety of industrial processes and is typically addressed by dispensing antifreeze substances such as salts and glycols. Despite the popularity of this anti-icing approach, some of the intricate underlying physical mechanisms are just being unraveled. For example, recent studies have shown that in addition to suppressing ice formation within its own volume, an individual salt saturated water microdroplet forms a region of inhibited condensation and condensation frosting (RIC) in its surrounding area. This occurs because salt saturated water, like most antifreeze substances, is hygroscopic and has water vapor pressure at its surface lower than water saturation pressure at the substrate. Here, we demonstrate that for macroscopic drops of propylene glycol and salt saturated water, the absolute RIC size can remain essentially unchanged for several hours. Utilizing this observation, we demonstrate that frost formation can be completely inhibited in-between microscopic and macroscopic arrays of propylene glycol and salt saturated water drops with spacing (S) smaller than twice the radius of the RIC (δ). Furthermore, by characterizing condensation frosting dynamics around various hygroscopic drop arrays, we demonstrate that they can delay complete frosting over of the samples 1.6 to 10 times longer than films of the liquids with equivalent volume. The significant delay in onset of ice nucleation achieved by dispensing propylene glycol in drops rather than in films is likely due to uniform dilution of the drops driven by thermocapillary flow. This transport mode is absent in the films, leading to faster dilution, and with that facilitated homogeneous nucleation, near the liquid-air interface. PMID:26651017

  20. Comparison of backbone dynamics of the type III antifreeze protein and antifreeze-like domain of human sialic acid synthase

    International Nuclear Information System (INIS)

    Antifreeze proteins (AFPs) are found in a variety of cold-adapted (psychrophilic) organisms to promote survival at subzero temperatures by binding to ice crystals and decreasing the freezing temperature of body fluids. The type III AFPs are small globular proteins that consist of one α-helix, three 310-helices, and two β-strands. Sialic acids play important roles in a variety of biological functions, such as development, recognition, and cell adhesion and are synthesized by conserved enzymatic pathways that include sialic acid synthase (SAS). SAS consists of an N-terminal catalytic domain and a C-terminal antifreeze-like (AFL) domain, which is similar to the type III AFPs. Despite having very similar structures, AFL and the type III AFPs exhibit very different temperature-dependent stability and activity. In this study, we have performed backbone dynamics analyses of a type III AFP (HPLC12 isoform) and the AFL domain of human SAS (hAFL) at various temperatures. We also characterized the structural/dynamic properties of the ice-binding surfaces by analyzing the temperature gradient of the amide proton chemical shift and its correlation with chemical shift deviation from random coil. The dynamic properties of the two proteins were very different from each other. While HPLC12 was mostly rigid with a few residues exhibiting slow motions, hAFL showed fast internal motions at low temperature. Our results provide insight into the molecular basis of thermostability and structural flexibility in homologous psychrophilic HPLC12 and mesophilic hAFL proteins

  1. Comparison of backbone dynamics of the type III antifreeze protein and antifreeze-like domain of human sialic acid synthase

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong-Geun [Gyeongsang National University, Department of Chemistry and Research Institute of Natural Science (Korea, Republic of); Park, Chin-Ju [Gwangju Institute of Science and Technology, Division of Liberal Arts and Sciences and Department of Chemistry (Korea, Republic of); Kim, Hee-Eun; Seo, Yeo-Jin; Lee, Ae-Ree; Choi, Seo-Ree; Lee, Shim Sung; Lee, Joon-Hwa, E-mail: joonhwa@gnu.ac.kr [Gyeongsang National University, Department of Chemistry and Research Institute of Natural Science (Korea, Republic of)

    2015-02-15

    Antifreeze proteins (AFPs) are found in a variety of cold-adapted (psychrophilic) organisms to promote survival at subzero temperatures by binding to ice crystals and decreasing the freezing temperature of body fluids. The type III AFPs are small globular proteins that consist of one α-helix, three 3{sub 10}-helices, and two β-strands. Sialic acids play important roles in a variety of biological functions, such as development, recognition, and cell adhesion and are synthesized by conserved enzymatic pathways that include sialic acid synthase (SAS). SAS consists of an N-terminal catalytic domain and a C-terminal antifreeze-like (AFL) domain, which is similar to the type III AFPs. Despite having very similar structures, AFL and the type III AFPs exhibit very different temperature-dependent stability and activity. In this study, we have performed backbone dynamics analyses of a type III AFP (HPLC12 isoform) and the AFL domain of human SAS (hAFL) at various temperatures. We also characterized the structural/dynamic properties of the ice-binding surfaces by analyzing the temperature gradient of the amide proton chemical shift and its correlation with chemical shift deviation from random coil. The dynamic properties of the two proteins were very different from each other. While HPLC12 was mostly rigid with a few residues exhibiting slow motions, hAFL showed fast internal motions at low temperature. Our results provide insight into the molecular basis of thermostability and structural flexibility in homologous psychrophilic HPLC12 and mesophilic hAFL proteins.

  2. A study of the growth rates and growth habits of ice crystals in a solution of antifreeze (glyco) proteins

    Science.gov (United States)

    Li, Qianzhong; Luo, Liaofu

    1996-12-01

    The mechanism of the antifreeze glycoprotein/antifreeze protein interaction on the surface of ice is analyzed. The theory of ice crystal growth in an AF(G)P solution is presented. A quantitative calculation of the growth rates for gain growth has been obtained. The anisotropic growth habits and growth rates of ice crystals in an AF(G)P solution are explained.

  3. Synthesis of Cyclic Antifreeze Glycopeptide and Glycopeptoids and Their Ice Recrystallization Inhibition Activity

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Mija; Murugan, Ravichandran N.; Bang, Jeong Kyu; Kim, Hak Jun [Korea Basic Science Institute, Daejeon (Korea, Republic of); Shin, Song Yub [Chousn Univ., Gwangju (Korea, Republic of); Kim, Eunjung; Lee, Jun Hyuck [Korea Polar Research Institute, Incheon (Korea, Republic of)

    2012-11-15

    Until now, few groups reported the antifreeze activity of cyclic glycopeptides; however, the tedious synthetic procedure is not amenable to study the intensive structure activity relationship. A series of N-linked cyclic glycopeptoids and glycopeptide have been prepared to evaluate antifreeze activity as a function of peptide backbone cyclization and methyl stereochemical effect on the rigid Thr position. This study has combined the cyclization protocol with solid phase peptide synthesis and obtained significant quantities of homogeneous cyclic glycopeptide and glycopeptoids. Analysis of antifreeze activity revealed that our cyclic peptide demonstrated RI activity while cyclic glycopeptoids showed no RI activity. These results suggest that the subtle changes in conformation and Thr orientation dramatically influence RI activity of N-linked glycopeptoids.

  4. Antifreeze proteins in the Antarctic springtail, Gressittacantha terranova.

    Science.gov (United States)

    Hawes, T C; Marshall, C J; Wharton, D A

    2011-08-01

    Antarctic springtails are exemplars of extreme low temperature adaptation in terrestrial arthropods. This paper represents the first examination of such adaptation in the springtail, Gressittacantha terranova. Acclimatization state was measured in field-fresh samples over a 22-day period at the beginning of the austral summer. No evidence of temperature tracking was observed. Mean temperature of crystallization (T(c)) for all samples was -20.67 ± 0.32°C and the lowest T(c) recorded was -32.62°C. Ice affinity purification was used to collect antifreeze proteins (AFPs) from springtail homogenate. The purified ice fraction demonstrated both thermal hysteresis activity and recrystallisation inhibition. Growth-melt observations revealed that ice crystals grow normal to the c-axis (basal plane). Reverse-phased HPLC produce one clearly resolved peak (P1) and one compound peak (P2). Mass spectrometry identified the molecular mass of P1 as 8,599 Da. The P1 protein was also the most prominent in P2, although additional peptides of 6-7 KDa were also prominent. The main AFP of the Antarctic springtail, G. terranova has been isolated, although like other AFP-expressing arthropods, it shows evidence of expressing a family of AFPs. PMID:21399953

  5. A root bond between ice and antifreeze protein.

    Science.gov (United States)

    Hawes, Timothy C

    2016-10-01

    It has always been assumed that a three-dimensional protein structure is essential to antifreeze protein (AFP) ice interactions. Using a 9 kDa AFP isolated from the springtail, Gomphiocephalus hodgsoni, it was found that the bond between ice and protein is maintained independent of higher order protein structure. GomplyAFP9 remained bound to ice after denaturing by a range of agents (boiling, extreme pH, DTT, ethanol, urea). Thermal hysteresis was minimal (0.03-0.04 °C), but not lost. Crystal faceting and growth occurred normal to the c-axis, indicating the protein binds primarily to sites along the a-axis. These observations lend additional support to the hypothesis of irreversible binding. More significantly, they suggest that binding to ice and functional hysteresis may be achieved independently (i.e. are different operations). These results are consistent with the view that there is a root bond with ice and it is achieved via an amino acid derived interface that bonds to water molecules in aqueous solutions. PMID:27542583

  6. Antifreeze polymeric additives for fuels; Aditivos polimericos anticongelantes para combustiveis

    Energy Technology Data Exchange (ETDEWEB)

    Muniz, Aline S.; Carvalho, Agne Roani de; Sakae, George Hideki; Oliveira, Angelo R.S.; Cesar-Oliveira, Maria Aparecida F. [Universidade Federal do Parana - UFPR - Departamento de Quimica - LABPOL-Laboratorio de Polimeros Sinteticos, Centro Politecnico, Curitiba, PR (Brazil)], e-mails: mafco@ufpr.br, alinemuniz@ufpr.br

    2011-07-01

    Owing to the current interest in the reduction of environmental pollution, several researchers are seeking renewable sources of energy which can at least partially replace combustibles derived from petroleum. Diesel oil is the combustible that most seriously pollutes the environment and is thus the biodiesel that is being considered as a fuel which can be replaced by a renewable combustible; this can possibly be used in diesel engines without any modifications. However, certain problems have to be overcome with regard to the temperature at which the biodiesel should be stored and used, since there is a tendency for biodiesel to solidify at low temperatures. This suggests that there is a need for the use of anti-freeze additives. This work behind the main focus additives with only 25 ppm, were able to reduce the pour point of fuel, achieving significant results, for example, the additive M14A18 lowered the pour point (PP) of B20 to -20 degree C, showing that the use of increasing amounts of biodiesel to diesel can aggregate. The main focus of work behind the development of additives that with only 25 ppm, were able to reduce the pour point of fuel, producing significant results such as those obtained with the use of additive M14A18 which lowered the pour point of the B20 to -20 degree C, showing the possibility of using increasing amounts of biodiesel added to diesel. (author)

  7. Nonequilibrium antifreeze peptides and the recrystallization of ice.

    Science.gov (United States)

    Knight, C A; Wen, D; Laursen, R A

    1995-02-01

    Evidence is presented that the nonequilibrium antifreeze peptide (AFP) from winter flounder has a special ability to inhibit recrystallization in ice only when an appreciable amount of liquid is present, as is the case when the system contains salts and the temperature is not too low. In this circumstance the AFP binds to the ice surface at the ice-solution interfaces in grain boundaries, preventing migration of the solution and effectively immobilizing the boundaries. In the absence of liquid, recrystallization inhibition appears to be a common property of many peptides. This is consistent with the view that the special effects of AFPs require a structural fit onto ice, and therefore require the AFP molecules to have the mobility to achieve that fit. Since the concentration of salt required to induce the special recrystallization inhibition effects of AFPs is lower (recrystallization. The proposition that mobility is needed for AFP molecules to produce their special influence upon ice growth argues against any special effects of AFPs in devitrification.

  8. Effect of Antifreeze Peptide Pretreatment on Ice Crystal Size, Drip Loss, Texture, and Volatile Compounds of Frozen Carrots.

    Science.gov (United States)

    Kong, Charles H Z; Hamid, Nazimah; Liu, Tingting; Sarojini, Vijayalekshmi

    2016-06-01

    Ice crystal formation is of primary concern to the frozen food industry. In this study, the effects of antifreeze peptides (AFPs) on ice crystal formation were assessed in carrot during freezing and thawing. Three synthetic analogues based on naturally occurring antifreeze peptides were used in this study. The AFPs exhibited modification of ice crystal morphology, confirming their antifreeze activity in vitro. The ability of the synthetic AFPs to minimize drip loss and preserve color, structure, texture, and volatiles of frozen carrot was evaluated using the techniques of SEM, GC-MS, and texture analysis. The results prove the potential of these AFPs to preserve the above characteristics in frozen carrot samples. PMID:27138051

  9. Research Progress on Insect Antifreeze Proteins%昆虫抗冻蛋白研究进展

    Institute of Scientific and Technical Information of China (English)

    万军; 朱兴友; 张洋

    2012-01-01

    近年来昆虫抗冻蛋白(AFPs)的研究取得了较快的发展。本文综述了昆虫抗冻蛋白的发现过程、结构特点、表达规律、抗冻机制及相关的昆虫基因工程简况。%In recent years, the research of insect antifreeze proteins has developed rapidly. The discovery process, structural characteristics, expression laws and antifreeze mechanism of insect antifreeze proteins, as well as the related insect gene engineering research were reviewed in this paper.

  10. 几种昆虫抗冻蛋白的研究概况%Research overview on several insect antifreeze proteins

    Institute of Scientific and Technical Information of China (English)

    李亚平; 刘丽娟

    2012-01-01

    昆虫抗冻蛋白具有很强的抗冻活性,其结构与其他生物不同.本文分别从结构、基因克隆、抗冻活性等方面对几种昆虫的抗冻蛋白进行综述,并对昆虫抗冻蛋白的发展前景进行了展望.%Insect antifreeze proteins have special structures and have stronger antifreeze activity than antifreeze proteins of other organisms. In this paper, the special properties of insect antifreeze proteins are reviewed. New advances on gene cloning and antifreeze activity are introduced in detail and the development perspectives of insect antifreeze proteins are prospected.

  11. 复合防冻剂的防冻机理及施工要求%On the Antifreeze Mechanism and the Construction Requirements of Antifreeze Compound

    Institute of Scientific and Technical Information of China (English)

    王超

    2011-01-01

    Concrete is the most widely used material in construction,.The durability of concrete which is strongly influenced by its frost resistance has raised great attention.Therefore,improving and developing concrete of good frost resistance has very significant economic and social benefits.Using concrete with antifreeze compound can achieve convenient construction,can conserve energy,can save concrete cost and improve the quality of concrete constructed in winter.It can not only reduce the liquid freezing point of concrete,but can promote freezing and save water as well.Therefore,understanding the antifreeze mechanism and the construction requirements of antifreeze compound can achieve better technical economic benefit.%在建筑工程中,混凝土是使用最广泛的一种材料,混凝土的耐久性受到人们的普遍关注,其中冻害性是影响混凝土耐久性的一个最重要的因素。改善并开发抗冻性能良好的混凝土具有非常重大的经济效益与社会效益。而采用掺复合防冻剂混凝土具有施工简便、节能、节约混凝土冬施费用,提高混凝土冬施质量等优点,它不仅能够降低混凝土中液相冰点,同时还具有促凝、早强和减水作用。

  12. Structural characteristics of a novel antifreeze protein from the longhorn beetle Rhagium inquisitor

    DEFF Research Database (Denmark)

    Kristiansen, E; Ramløv, Hans; Højrup, Peter;

    2011-01-01

    Antifreeze proteins (AFPs) are characterized by their capacity to inhibit the growth of ice and are produced by a variety of polar fish, terrestrial arthropods and other organisms inhabiting cold environments. This capacity reflects their role as stabilizers of supercooled body fluids. The longhorn...... beetle Rhagium inquisitor is known to express AFPs in its body fluids. In this work we report on the primary structure and structural characteristics of a 12.8 kDa AFP from this beetle (RiAFP). It has a high capacity to evoke antifreeze activity as compared to other known insect AFPs and it is...... structurally unique in several aspects. In contrast to the high content of disulfide bond-formation observed in other coleopteran AFPs, RiAFP contains only a single such bond. Six internal repeat segments of a thirteen residue repeat pattern is irregularly spaced apart throughout its sequence. The central part...

  13. Thermodynamic Properties of Linear Protein Solutions: an Application to Type Ⅰ Antifreeze Protein Solutions

    Institute of Scientific and Technical Information of China (English)

    LI Li-fen; LIANG Xi-xia; LI Qian-zhong

    2012-01-01

    A statistical thermodynamic theory of linear protein solutions was proposed with the aid of a lattice model and applied to type Ⅰ antifreeze protein(AFPI) solutions.The numerical results for several AFPI solutions show that the Gibbs function of the solution has a minimum at a certain protein concentration,but the protein chemical potential increases with increasing the concentration.The influences of temperature and protein chain length on the AFPI chemical potential were also discussed.The evaluation for the colligative depression of the freezing point confirms that the antifreeze action should be recognized as non-colligative.The theoretical deduction for the concentration dependence of the thermal hysteresis activity coincides qualitatively with the previous experimental and theoretical results.

  14. An Investigation of Freezing of Supercooled Water on Anti-Freeze Protein Modified Surfaces

    Institute of Scientific and Technical Information of China (English)

    Thibaut V J Charpentier; Anne Neville; Paul Millner; Rob Hewson; Ardian Morina

    2013-01-01

    This work investigates how functionalization ofaluminium surfaces with natural type Ⅲ Anti-Freeze Protein (AFP) affects the mechanism of heterogeneous ice nucleation.First the bulk ice nucleation properties of distilled water and aqueous solution of AFP were evaluated by differential scanning calorimetry.Then the modified surface was characterized by Secondary Ions Mass Spectroscopy (SIMS),Fourier Transform InfraRed (FTIR) spectroscopy and contact angle measurement.Freezing experiments were then conducted in which water droplets underwent a slow controlled cooling.This study shows that compared to uncoated aluminium,the anti-freeze proteins functionalized surfaces exhibit a higher and narrower range of freezing temperature.It was found that these proteins that keep living organisms from freezing in cold environment act in the opposite way once immobilized on surfaces by promoting ice nucleation.Some suggestions regarding the mechanism of action of the observed phenomena were proposed based on the Classical Nucleation Theory (CNT).

  15. The response of watercress (nasturtium officinale) to vacuum impregnation: Effect of an antifreeze protein type I

    OpenAIRE

    Rui M.S. Cruz; Vieira, Margarida C.; Silva, Cristina L. M.

    2009-01-01

    The setting up of methodologies that reduce the size of ice crystals and reduce or inhibit the recrystallisation phenomena could have an extraordinary significance in the final quality of frozen products and consequently bring out new market opportunities. In this work, the effect of an antifreeze protein type I (AFP-I), by vacuum impregnation (VI), on frozen watercress was studied. The VI pressure, samples’ weight, Hunter Lab colour, scanning electron microscopy (SEM), and a wilting test ...

  16. Evaluation of anti-freeze viscosity modifier for potential external tank applications

    Science.gov (United States)

    Lynn, R. O. L.

    1981-01-01

    Viscosity modifiers and gelling agents were evaluated in combination with ethylene glycol and dimethyl sulfoxide water eutectics. Pectin and agarose are found to gel these eutectics effectively in low concentration, but the anti-freeze protection afforded by these compositions is found to be marginal in simulations of the intended applications. Oxygen vent shutters and vertical metallic surfaces were simulated, with water supplied as a spray, dropwise, and by condensation from the air.

  17. Antifreeze proteins govern the precipitation of trehalose in a freezing-avoiding insect at low temperature

    OpenAIRE

    WEN, Xin; Wang, Sen; Duman, John G.; Arifin, Josh Fnu; Juwita, Vonny; Goddard, William A.; Rios, Alejandra; Liu, Fan; Kim, Soo-Kyung; Abrol, Ravinder; DeVries, Arthur L.; Henling, Lawrence M.

    2016-01-01

    The remarkable adaptive strategies of insects to extreme environments are linked to the biochemical compounds in their body fluids. Trehalose, a versatile sugar molecule, can accumulate to high levels in freeze-tolerant and freeze-avoiding insects, functioning as a cryoprotectant and a supercooling agent. Antifreeze proteins (AFPs), known to protect organisms from freezing by lowering the freezing temperature and deferring the growth of ice, are present at high levels in some freeze-avoiding ...

  18. Snow-mold-induced apoplastic proteins in winter rye leaves lack antifreeze activity

    Science.gov (United States)

    Hiilovaara-Teijo; Hannukkala; Griffith; Yu; Pihakaski-Maunsbach

    1999-10-01

    During cold acclimation, winter rye (Secale cereale L.) plants secrete antifreeze proteins that are similar to pathogenesis-related (PR) proteins. In this experiment, the secretion of PR proteins was induced at warm temperatures by infection with pink snow mold (Microdochium nivale), a pathogen of overwintering cereals. A comparison of cold-induced and pathogen-induced proteins showed that PR proteins accumulated in the leaf apoplast to a greater level in response to cold. The PR proteins induced by cold and by snow mold were similar when separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and examined by immunoblotting. Both groups of PR proteins contained glucanase-like, chitinase-like, and thaumatin-like proteins, and both groups exhibited similar levels of glucanase and chitinase activities. However, only the PR proteins induced by cold exhibited antifreeze activity. Our findings suggest that the cold-induced PR proteins may be isoforms that function as antifreeze proteins to modify the growth of ice during freezing while also providing resistance to the growth of low-temperature pathogens in advance of infection. Both functions of the cold-induced PR proteins may improve the survival of overwintering cereals.

  19. Role of ice nucleation and antifreeze activities in pathogenesis and growth of snow molds.

    Science.gov (United States)

    Snider, C S; Hsiang, T; Zhao, G; Griffith, M

    2000-04-01

    ABSTRACT We examined the ability of snow molds to grow at temperatures from -5 to 30 degrees C and to influence the growth of ice through assays for ice nucleation and antifreeze activities. Isolates of Coprinus psychromorbidus (low temperature basidiomycete variant), Microdochium nivale, Typhula phacorrhiza, T. ishikariensis, T. incarnata, and T. canadensis all grew at -5 degrees C, whereas Sclerotinia borealis and S. homoeocarpa did not grow at temperatures below 4 degrees C. The highest threshold ice nucleation temperature was -7 degrees C. Because snow molds are most damaging to their hosts at temperatures above this, our results imply that the pathogenesis of these fungi is not dependent on ice nucleation activity to cause freeze-wounding of host plants. All snow molds that grew at subzero temperatures also exhibited antifreeze activity in the growth medium and in the soluble and insoluble hyphal fractions, with the exception of M. nivale and one isolate of T. canadensis. The lack of high ice nucleation activity combined with the presence of antifreeze activity in all fungal fractions indicates that snow molds can moderate their environment to inhibit or modify intra- and extracellular ice formation, which helps explain their ability to grow at subzero temperatures under snow cover.

  20. Interaction of Tenebrio Molitor Antifreeze Protein with Ice Crystal: Insights from Molecular Dynamics Simulations.

    Science.gov (United States)

    Ramya, L; Ramakrishnan, Vigneshwar

    2016-07-01

    Antifreeze proteins (AFP) observed in cold-adapting organisms bind to ice crystals and prevent further ice growth. However, the molecular mechanism of AFP-ice binding and AFP-inhibited ice growth remains unclear. Here we report the interaction of the insect antifreeze protein (Tenebrio molitor, TmAFP) with ice crystal by molecular dynamics simulation studies. Two sets of simulations were carried out at 263 K by placing the protein near the primary prism plane (PP) and basal plane (BL) of the ice crystal. To delineate the effect of temperatures, both the PP and BL simulations were carried out at 253 K as well. The analyses revealed that the protein interacts strongly with the ice crystal in BL simulation than in PP simulation both at 263 K and 253 K. Further, it was observed that the interactions are primarily mediated through the interface waters. We also observed that as the temperature decreases, the interaction between the protein and the ice increases which can be attributed to the decreased flexibility and the increased structuring of the protein at low temperature. In essence, our study has shed light on the interaction mechanism between the TmAFP antifreeze protein and the ice crystal. PMID:27492241

  1. Adsorption thermodynamics of two-domain antifreeze proteins: theory and Monte Carlo simulations.

    Science.gov (United States)

    Narambuena, Claudio F; Sanchez Varretti, Fabricio O; Ramirez-Pastor, Antonio J

    2016-09-21

    In this paper we develop the statistical thermodynamics of two-domain antifreeze proteins adsorbed on ice. We use a coarse-grained model and a lattice network in order to represent the protein and ice, respectively. The theory is obtained by combining the exact analytical expression for the partition function of non-interacting linear k-mers adsorbed in one dimension, and its extension to higher dimensions. The total and partial adsorption isotherms, and the coverage and temperature dependence of the Helmholtz free energy and configurational entropy are given. The formalism reproduces the classical Langmuir equation, leads to the exact statistical thermodynamics of molecules adsorbed in one dimension, and provides a close approximation for two-dimensional systems. Comparisons with analytical data obtained using the modified Langmuir model (MLM) and Monte Carlo simulations in the grand canonical ensemble were performed in order to test the validity of the theoretical predictions. In the MC calculations, the different mechanisms proposed in the literature to describe the adsorption of two-domain antifreeze proteins on ice were analyzed. Indistinguishable results were obtained in all cases, which verifies the thermodynamic equivalence of these mechanisms and allows the choice of the most suitable mechanism for theoretical studies of equilibrium properties. Even though a good qualitative agreement is obtained between MLM and MC data, it is found that the new theoretical framework offers a more accurate description of the phenomenon of adsorption of two-domain antifreeze proteins. PMID:27539563

  2. A low molecular weight peptide from snow mold with epitopic homology to the winter flounder antifreeze protein.

    Science.gov (United States)

    Newsted, W J; Polvi, S; Papish, B; Kendall, E; Saleem, M; Koch, M; Hussain, A; Cutler, A J; Georges, F

    1994-01-01

    Evidence for a small size protein (ca. 3500 kDa) exhibiting epitopic homology to the Atlantic winter flounder antifreeze protein (AFP) is found in the snow molds Coprinus psychromorbidus, Myriosclerotinia borealis, and Typhula incarnata. The protein shows strong cross-reactivity with antisera specific for the flounder AFP. Preliminary studies suggest that the protein is synthesized in response to lowering the culture temperature, and that it is membrane associated and, therefore, may function in an analogous capacity to the fish AFP. Also, the protein is shown to have antifreeze properties as determined by nuclear magnetic resonance microimaging experiments.

  3. Animal ice-binding (antifreeze) proteins and glycolipids: an overview with emphasis on physiological function.

    Science.gov (United States)

    Duman, John G

    2015-06-01

    Ice-binding proteins (IBPs) assist in subzero tolerance of multiple cold-tolerant organisms: animals, plants, fungi, bacteria etc. IBPs include: (1) antifreeze proteins (AFPs) with high thermal hysteresis antifreeze activity; (2) low thermal hysteresis IBPs; and (3) ice-nucleating proteins (INPs). Several structurally different IBPs have evolved, even within related taxa. Proteins that produce thermal hysteresis inhibit freezing by a non-colligative mechanism, whereby they adsorb onto ice crystals or ice-nucleating surfaces and prevent further growth. This lowers the so-called hysteretic freezing point below the normal equilibrium freezing/melting point, producing a difference between the two, termed thermal hysteresis. True AFPs with high thermal hysteresis are found in freeze-avoiding animals (those that must prevent freezing, as they die if frozen) especially marine fish, insects and other terrestrial arthropods where they function to prevent freezing at temperatures below those commonly experienced by the organism. Low thermal hysteresis IBPs are found in freeze-tolerant organisms (those able to survive extracellular freezing), and function to inhibit recrystallization - a potentially damaging process whereby larger ice crystals grow at the expense of smaller ones - and in some cases, prevent lethal propagation of extracellular ice into the cytoplasm. Ice-nucleator proteins inhibit supercooling and induce freezing in the extracellular fluid at high subzero temperatures in many freeze-tolerant species, thereby allowing them to control the location and temperature of ice nucleation, and the rate of ice growth. Numerous nuances to these functions have evolved. Antifreeze glycolipids with significant thermal hysteresis activity were recently identified in insects, frogs and plants. PMID:26085662

  4. Unusual dynamic properties of water near the ice-binding plane of hyperactive antifreeze protein

    Energy Technology Data Exchange (ETDEWEB)

    Kuffel, Anna; Czapiewski, Dariusz; Zielkiewicz, Jan, E-mail: jaz@chem.pg.gda.pl [Department of Chemistry, Gdansk University of Technology, Narutowicza 11/12, 80–233 Gdansk (Poland)

    2015-10-07

    The dynamical properties of solvation water of hyperactive antifreeze protein from Choristoneura fumiferana (CfAFP) are analyzed and discussed in context of its antifreeze activity. The protein comprises of three well-defined planes and one of them binds to the surface of ice. The dynamical properties of solvation water around each of these planes were analyzed separately; the results are compared with the dynamical properties of solvation water of ice around its two crystallographic planes: basal and prism. Three main conclusions are inferred from our investigations. The first one is that the solvation shell of CfAFP does not seem to be particularly far-ranged, at least not beyond what is usually observed for proteins that do not interact with ice. Therefore, it does not appear to us that the antifreeze activity is enhanced by a long-ranged retardation of water mobility. Also the correlation between the collective mobility of water and the collective mobility of protein atoms highly resembles the one measured for the protein that does not interact with ice. Our second conclusion is that the dynamical properties of solvation water of CfAFP are non-uniform. The dynamics of solvation water of ice-binding plane is, in some respects, different from the dynamics of solvation water of the two remaining planes. The feature that distinguishes the dynamics of solvation water of the three planes is the activation energy of diffusion process. The third conclusion is that—from the three analyzed solvation shells of CfAFP—the dynamical properties of solvation water of the ice-binding plane resemble the most the properties of solvation water of ice; note, however, that these properties still clearly differ from the dynamic properties of solvation water of ice.

  5. Unusual dynamic properties of water near the ice-binding plane of hyperactive antifreeze protein

    International Nuclear Information System (INIS)

    The dynamical properties of solvation water of hyperactive antifreeze protein from Choristoneura fumiferana (CfAFP) are analyzed and discussed in context of its antifreeze activity. The protein comprises of three well-defined planes and one of them binds to the surface of ice. The dynamical properties of solvation water around each of these planes were analyzed separately; the results are compared with the dynamical properties of solvation water of ice around its two crystallographic planes: basal and prism. Three main conclusions are inferred from our investigations. The first one is that the solvation shell of CfAFP does not seem to be particularly far-ranged, at least not beyond what is usually observed for proteins that do not interact with ice. Therefore, it does not appear to us that the antifreeze activity is enhanced by a long-ranged retardation of water mobility. Also the correlation between the collective mobility of water and the collective mobility of protein atoms highly resembles the one measured for the protein that does not interact with ice. Our second conclusion is that the dynamical properties of solvation water of CfAFP are non-uniform. The dynamics of solvation water of ice-binding plane is, in some respects, different from the dynamics of solvation water of the two remaining planes. The feature that distinguishes the dynamics of solvation water of the three planes is the activation energy of diffusion process. The third conclusion is that—from the three analyzed solvation shells of CfAFP—the dynamical properties of solvation water of the ice-binding plane resemble the most the properties of solvation water of ice; note, however, that these properties still clearly differ from the dynamic properties of solvation water of ice

  6. STUDY ON PROPERTIES OF SKID RESISTANCE ON FREEZING PAVEMENTS AND QUANTITATIVE EVALUATION METHOD OF ANTIFREEZING EFFECTS

    Science.gov (United States)

    Tanaka, Shunsuke; Takeichi, Kiyoshi; Masuyama, Yukiei; Takahashi, Naoto

    Snow and ice control in winter roads trends to be controlled by the skid friction coefficients in North America and North European countries at present, but the measurements are not necessarily easy. We studied on a simplified measurement method based on the relationship between skid friction coefficients and the bare pavement ratio (BPR) in the laboratory tests and field tests. The factors of BPR, surface textures and antifreezing materials which affect the skid friction coefficient are reviewed by a multiple linear regression analysis and a spectrum analysis, considering different freezing surfaces. These studies indicate that conclusions induced by laboratory tests could be applied to roads in service.

  7. An open source cryostage and software analysis method for detection of antifreeze activity

    DEFF Research Database (Denmark)

    Lørup Buch, Johannes; Ramløv, H

    2016-01-01

    The aim of this study is to provide the reader with a simple setup that can detect antifreeze proteins (AFP) by inhibition of ice recrystallisation in very small sample sizes. This includes an open source cryostage, a method for preparing and loading samples as well as a software analysis method....... The entire setup was tested using hyperactive AFP from the cerambycid beetle, Rhagium mordax. Samples containing AFP were compared to buffer samples, and the results are visualised as crystal radius evolution over time and in absolute change over 30 min. Statistical analysis showed that samples containing...

  8. Molecular cloning, sequence analysis and homology modeling of the first caudata amphibian antifreeze-like protein in axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Zhang, Songyan; Gao, Jiuxiang; Lu, Yiling; Cai, Shasha; Qiao, Xue; Wang, Yipeng; Yu, Haining

    2013-08-01

    Antifreeze proteins (AFPs) refer to a class of polypeptides that are produced by certain vertebrates, plants, fungi, and bacteria and which permit their survival in subzero environments. In this study, we report the molecular cloning, sequence analysis and three-dimensional structure of the axolotl antifreeze-like protein (AFLP) by homology modeling of the first caudate amphibian AFLP. We constructed a full-length spleen cDNA library of axolotl (Ambystoma mexicanum). An EST having highest similarity (∼42%) with freeze-responsive liver protein Li16 from Rana sylvatica was identified, and the full-length cDNA was subsequently obtained by RACE-PCR. The axolotl antifreeze-like protein sequence represents an open reading frame for a putative signal peptide and the mature protein composed of 93 amino acids. The calculated molecular mass and the theoretical isoelectric point (pl) of this mature protein were 10128.6 Da and 8.97, respectively. The molecular characterization of this gene and its deduced protein were further performed by detailed bioinformatics analysis. The three-dimensional structure of current AFLP was predicted by homology modeling, and the conserved residues required for functionality were identified. The homology model constructed could be of use for effective drug design. This is the first report of an antifreeze-like protein identified from a caudate amphibian. PMID:23915159

  9. Molecular cloning, sequence analysis and homology modeling of the first caudata amphibian antifreeze-like protein in axolotl (Ambystoma mexicanum).

    Science.gov (United States)

    Zhang, Songyan; Gao, Jiuxiang; Lu, Yiling; Cai, Shasha; Qiao, Xue; Wang, Yipeng; Yu, Haining

    2013-08-01

    Antifreeze proteins (AFPs) refer to a class of polypeptides that are produced by certain vertebrates, plants, fungi, and bacteria and which permit their survival in subzero environments. In this study, we report the molecular cloning, sequence analysis and three-dimensional structure of the axolotl antifreeze-like protein (AFLP) by homology modeling of the first caudate amphibian AFLP. We constructed a full-length spleen cDNA library of axolotl (Ambystoma mexicanum). An EST having highest similarity (∼42%) with freeze-responsive liver protein Li16 from Rana sylvatica was identified, and the full-length cDNA was subsequently obtained by RACE-PCR. The axolotl antifreeze-like protein sequence represents an open reading frame for a putative signal peptide and the mature protein composed of 93 amino acids. The calculated molecular mass and the theoretical isoelectric point (pl) of this mature protein were 10128.6 Da and 8.97, respectively. The molecular characterization of this gene and its deduced protein were further performed by detailed bioinformatics analysis. The three-dimensional structure of current AFLP was predicted by homology modeling, and the conserved residues required for functionality were identified. The homology model constructed could be of use for effective drug design. This is the first report of an antifreeze-like protein identified from a caudate amphibian.

  10. An Effective Antifreeze Protein Predictor with Ensemble Classifiers and Comprehensive Sequence Descriptors

    Directory of Open Access Journals (Sweden)

    Runtao Yang

    2015-09-01

    Full Text Available Antifreeze proteins (AFPs play a pivotal role in the antifreeze effect of overwintering organisms. They have a wide range of applications in numerous fields, such as improving the production of crops and the quality of frozen foods. Accurate identification of AFPs may provide important clues to decipher the underlying mechanisms of AFPs in ice-binding and to facilitate the selection of the most appropriate AFPs for several applications. Based on an ensemble learning technique, this study proposes an AFP identification system called AFP-Ensemble. In this system, random forest classifiers are trained by different training subsets and then aggregated into a consensus classifier by majority voting. The resulting predictor yields a sensitivity of 0.892, a specificity of 0.940, an accuracy of 0.938 and a balanced accuracy of 0.916 on an independent dataset, which are far better than the results obtained by previous methods. These results reveal that AFP-Ensemble is an effective and promising predictor for large-scale determination of AFPs. The detailed feature analysis in this study may give useful insights into the molecular mechanisms of AFP-ice interactions and provide guidance for the related experimental validation. A web server has been designed to implement the proposed method.

  11. Antifreeze and cryoprotective activities of ice-binding collagen peptides from pig skin.

    Science.gov (United States)

    Cao, Hui; Zhao, Ying; Zhu, Yu Bing; Xu, Fei; Yu, Jing Song; Yuan, Min

    2016-03-01

    A novel "hyperactive" ice-binding peptide from porcine collagen was prepared by alkaline protease hydrolysis and a series of column chromatography separations, and then its antifreeze and cryoprotective properties were reported. Using differential scanning calorimetry (DSC), the thermal hysteresis (TH) of ice-binding collagen peptides was closely related to their concentration and crystal fraction. Collagen hydrolysates with maximal TH were obtained by hydrolysis at pH 8.0, DH 15.0%, and 5% alkaline protease at 55°C. After purification by column chromatography, the AP-3 ice-binding collagen peptide (GLLGPLGPRGLL) with 1162.8Da molecular weights exhibited the highest TH (5.28°C), which can be classified as "hyperactive". Recrystallisation and melt-resistance of ice cream were improved by AP-3 ice-binding collagen peptide at 0.2% (w/v) in a similar manner to natural antifreeze proteins. Moreover, the addition of AP-3 collagen peptides in ice cream greatly elevated the glass transition temperature (Tg) to -17.64°C. PMID:26471678

  12. The inhibition of ice nucleators by insect antifreeze proteins is enhanced by glycerol and citrate.

    Science.gov (United States)

    Duman, J G

    2002-02-01

    Antifreeze proteins depress the freezing point of water while not affecting the melting point, producing a characteristic difference in freezing and melting points termed thermal hysteresis. Larvae of the beetle Dendroides canadensis accumulate potent antifreeze proteins (DAFPs) in their hemolymph and gut, but to achieve high levels of thermal hysteresis requires enhancers, such as glycerol. DAFPs have previously been shown to inhibit the activity of bacterial and hemolymph protein ice nucleators, however, the effect was not large and therefore the effectiveness of the DAFPs in promoting supercooling of the larvae in winter was doubtful. However, this study demonstrates that DAFPs, in combination with the thermal hysteresis enhancers glycerol (1 M) or citrate (0.5 M), eliminated the activity of hemolymph protein ice nucleators and Pseudomonas syringae ice-nucleating active bacteria, and lowered the supercooling points (nucleation temperatures) of aqueous solutions containing these ice nucleators to those of water or buffer alone. This shows that the DAFPs, along with glycerol, play a critical role in promoting hemolymph supercooling in overwintering D. canadensis. Also, DAFPs in combination with enhancers may be useful in applications which require inhibition of ice nucleators. PMID:11916110

  13. Agrobacterium-mediated transformation of modified antifreeze protein gene in strawberry

    Directory of Open Access Journals (Sweden)

    Srisulak Dheeranupattana

    2005-07-01

    Full Text Available The optimum condition for shoot regeneration from leaf explants of strawberry cultivar Tiogar was investigated. It was found that the best regeneration condition was MS medium containing N6-Benzyladenine (BA and 2,4-Dichlorophenoxy acetic acid (2,4-D at concentrations of 1 mg.l-1 and 0.2 mg.l-1, respectively. Antibiotics sensitivity test found that shoot regeneration from leaf explant was inhibited more than 90% at the concentration of kanamycin (Km as low as 5 mg.l-1. The modified gene encoding antifreeze protein isoform HPLC 6 was successfully constructed using codons which were optimally expressed in the strawberry plant. The antifreeze protein genes, naturally in plasmid pSW1 and modified in plasmid BB, were transformed to strawberry leaf explants by Agrobacterium tumefaciens LBA 4404. The strawberry plants, transformed with both AFP genes, were able to root in MS media containing 50 mg.l-1 Km, while no roots grew from nontransformed plant in this condition. Polymerase chain reaction indicated that the transgenes were integrated in the genome of transformants.

  14. Evolution of Type II Antifreeze Protein Genes in Teleost Fish: A Complex Scenario Involving Lateral Gene Transfers and Episodic Directional Selection

    OpenAIRE

    Ulf Sorhannus

    2012-01-01

    I examined hypotheses about lateral transfer of type II antifreeze protein (AFP) genes among “distantly” related teleost fish. The effects of episodic directional selection on amino acid evolution were also investigated. The strict consensus results showed that the type II AFP and type II antifreeze-like protein genes were transferred from Osmerus mordax to Clupea harengus, from the ancestral lineage of the Brachyopsis rostratus—Hemitripterus americanus clade to the ancestor of the Hypomesus ...

  15. Recent Advances in Research of Antifreeze Proteins%抗冻蛋白研究进展

    Institute of Scientific and Technical Information of China (English)

    李金耀; 马纪; 张富春

    2005-01-01

    Many overwintering organisms produce antifreeze proteins (AFPs) that can be adsorbed onto the surface of ice crystals and modify their growth. These proteins show great diversity in structures, and they have been found in a variety of organisms. AFPs from insects have higher thermal hysteresis activity than other organisms. Recent studies revealed the structures of AFPs and put forward different ice-binding models. No mechanism, however, can apply to all antifreeze proteins and the molecular interaction between AFPs and ice are not accurately resolved. AFPs can be applied extensively to agriculture, aquaculture and low temperature storage of organs, tissues, as well as cells. To confer transgenic plant cold resistance application of AFPs is essential, while the expression and regulation of antifreeze gene need to be elucidated.%很多越冬的生物会产生抗冻蛋白,这些抗冻蛋白能够吸附到冰晶的表面改变冰晶形态并抑制冰晶的生长.抗冻蛋白在很多生物体内都被发现,不同的抗冻蛋白结构差异非常大.目前的一些研究揭示了几种抗冻蛋白的结构,并提出了抗冻蛋白与冰晶的结合模型,但是还没有一种机制能解释所有抗冻蛋白的作用机理.抗冻蛋白能被广泛的应用到农业、水产业和低温储藏器官、组织和细胞,利用转基因技术提高植物的抗冻性具有重要应用价值.而抗冻蛋白基因的表达调控则有待进一步阐明.

  16. Numerical prediction of micro-channel LD heat sink operated with antifreeze based on CFD method

    Science.gov (United States)

    Liu, Gang; Liu, Yang; Wang, Chao; Wang, Wentao; Wang, Gang; Tang, Xiaojun

    2014-12-01

    To theoretically study the feasibility of antifreeze coolants applied as cooling fluids for high power LD heat sink, detailed Computational Fluid Dynamics (CFD) analysis of liquid cooled micro-channels heat sinks is presented. The performance operated with antifreeze coolant (ethylene glycol aqueous solution) compared with pure water are numerical calculated for the heat sinks with the same micro-channels structures. The maximum thermal resistance, total pressure loss (flow resistance), thermal resistance vs. flow-rate, and pressure loss vs. flow-rate etc. characteristics are numerical calculated. The results indicate that the type and temperature of coolants plays an important role on the performance of heat sinks. The whole thermal resistance and pressure loss of heat sinks increase significantly with antifreeze coolants compared with pure water mainly due to its relatively lower thermal conductivity and higher fluid viscosity. The thermal resistance and pressure loss are functions of the flow rate and operation temperature. Increasing of the coolant flow rate can reduce the thermal resistance of heat sinks; meanwhile increase the pressure loss significantly. The thermal resistance tends to a limit with increasing flow rate, while the pressure loss tends to increase exponentially with increasing flow rate. Low operation temperature chiefly increases the pressure loss rather than thermal resistance due to the remarkable increasing of fluid viscosity. The actual working point of the cooling circulation system can be determined on the basis of the pressure drop vs. flow rate curve for the micro-channel heat sink and that for the circulation system. In the same system, if the type or/and temperature of the coolant is changed, the working point is accordingly influenced, that is, working flow rate and pressure is changed simultaneously, due to which the heat sink performance is influenced. According to the numerical simulation results, if ethylene glycol aqueous

  17. Fluorescence microscopy studies of the hyperactive antifreeze protein from an insect

    Science.gov (United States)

    Pertaya, N.; di Prinzio, C. L.; Wilen, L.; Thomson, E.; Wettlaufer, J. S.; Marshall, C. B.; Davies, P. L.; Braslavsky, I.

    2006-03-01

    Antifreeze proteins (AFPs) protect animals from freezing by binding to extracellular ice and inhibiting its growth. Since the initial discovery of AFPs in fish, non-homologous types have been found in insects, plants, bacteria, fungi, and vertebrates. Different AFP types have diverse structures and varied activities. For example, AFPs produced by insects are much more active in inhibiting ice crystal growth compared to most AFPs found in fish or plants. By putting a fluorescent tag on an insect AFP we were able to visualize AFP binding to ice, to determine the ice crystal surfaces to which the AFP adheres, and to follow the kinetics of AFP binding to ice. We expect this approach will contribute to a better understanding of the mechanism of AFP activity and in particular the hyperactivity of insect AFPs.

  18. A 9 kDa antifreeze protein from the Antarctic springtail, Gomphiocephalus hodgsoni.

    Science.gov (United States)

    Hawes, T C; Marshall, C J; Wharton, D A

    2014-08-01

    A 9 kDA antifreeze protein (AFP) was isolated and purified from the Antarctic springtail, Gomphiocephalus hodgsoni. By combining selective sampling procedures and a modified ice affinity purification protocol it was possible to directly isolate a single AFP protein without recourse to chromatographic separation techniques. Mass spectrometry identified a single 9 kDa component in the purified ice fraction. Intramolecular disulphide bonding was suggested by the presence of 12 cysteine residues. The specific amino acid composition is unique, particularly with regard to the presence of histidine (11.5%). But it also shows noticeable commonalities with insect AFPs in the abundance of cysteine (13.8%), while simultaneously hinting, through the presence of glycine (11.5%), that the metabolic building blocks of AFPs in Collembola may have a phylogenetically-determined component. PMID:25025820

  19. Raman spectroscopy of antifreeze glycoproteins and their interaction with various substrates

    Science.gov (United States)

    Cui, Y.; Turner, G.; Alexander, V.; Smith, I.; Sease, A.; Guo, M.; Burger, A.; Morgan, S.; Yeh, Yin

    2004-11-01

    Micro-Raman spectra of a mixture of antifreeze glycoproteins (AFGP) 6, 7 and 8 have been measured in the range of 100 - 4500 cm-1 with He-Ne laser excitation. The spectra were obtained for both bulk AFGP and films of AFGP deposited on various substrates. New vibrational peaks have been observed for films which are not present in the spectra of the bulk samples. The results will be presented and mechanisms of interaction between the AFGP molecule and substrates will be proposed. The assignment of new peaks and the effects of the water presence will also be discussed. Research supported by the NSF Center for Biophotonics, managed by U.C. Davis, CA No. PHY 0120999, NSF Research Experiences for Undergraduates DMR-0139180 and by the MBRS program through NIH/NIGMS grant 1S06-GM62813-01.

  20. The Surface of Ice in the presence of Antifreeze Proteins studied by Atomic Force Microscopy

    Science.gov (United States)

    Zepeda, Salvador; Orme, Christine; Yeh, Yin

    2002-03-01

    The surface of ice has been a topic of interest for centuries. In particular, the surface structure and properties have been explored with the advent of new surface techniques. Several groups have convincingly shown a surface transition layer to exist between the solid-vapor interface as well as the solid-liquid interface. In addition, the characteristics of this region may be directly correlated with growth morphologies of ice. Certain peptide molecules have the ability to significantly alter the growth morphology of an ice crystal. Do these molecules simply disrupt this transition region? Or do they anchor themselves deep into it reaching the bulk-ice phase? And is there a similar mechanism by which they function? We use AFM to study the morphological changes to the true ice surface due to the presence antifreeze proteins. We will discuss the implications of our results on the longstanding debate to the above questions.

  1. Improvement of texture properties and flavor of frozen dough by carrot (Daucus carota) antifreeze protein supplementation.

    Science.gov (United States)

    Zhang, Chao; Zhang, Hui; Wang, Li; Gao, Hong; Guo, Xiao Na; Yao, Hui Yuan

    2007-11-14

    The effects of concentrated carrot protein (CCP) containing 15.4% (w/w) carrot (Daucus carota) antifreeze protein on texture properties of frozen dough and volatile compounds of crumb were studied. CCP supplementation lowered the freezable water content of the dough, resulting in some beneficial effects including holding loaf volume steadily and making the dough softer and steadier during frozen storage. Furthermore, SPME-GC-MS analysis showed CCP supplementation did not give any negative influences on volatile compounds of crumb and gave a pleasant aroma felt like Michelia alba DC from trans-caryophyllene simultaneously. Combining our previous results that CCP supplementation improves the fermentation capacity of the frozen dough, CCP could be used as a beneficial additive for frozen dough processing. PMID:17935294

  2. Antifreeze proteins govern the precipitation of trehalose in a freezing-avoiding insect at low temperature.

    Science.gov (United States)

    Wen, Xin; Wang, Sen; Duman, John G; Arifin, Josh Fnu; Juwita, Vonny; Goddard, William A; Rios, Alejandra; Liu, Fan; Kim, Soo-Kyung; Abrol, Ravinder; DeVries, Arthur L; Henling, Lawrence M

    2016-06-14

    The remarkable adaptive strategies of insects to extreme environments are linked to the biochemical compounds in their body fluids. Trehalose, a versatile sugar molecule, can accumulate to high levels in freeze-tolerant and freeze-avoiding insects, functioning as a cryoprotectant and a supercooling agent. Antifreeze proteins (AFPs), known to protect organisms from freezing by lowering the freezing temperature and deferring the growth of ice, are present at high levels in some freeze-avoiding insects in winter, and yet, paradoxically are found in some freeze-tolerant insects. Here, we report a previously unidentified role for AFPs in effectively inhibiting trehalose precipitation in the hemolymph (or blood) of overwintering beetle larvae. We determine the trehalose level (29.6 ± 0.6 mg/mL) in the larval hemolymph of a beetle, Dendroides canadensis, and demonstrate that the hemolymph AFPs are crucial for inhibiting trehalose crystallization, whereas the presence of trehalose also enhances the antifreeze activity of AFPs. To dissect the molecular mechanism, we examine the molecular recognition between AFP and trehalose crystal interfaces using molecular dynamics simulations. The theory corroborates the experiments and shows preferential strong binding of the AFP to the fast growing surfaces of the sugar crystal. This newly uncovered role for AFPs may help explain the long-speculated role of AFPs in freeze-tolerant species. We propose that the presence of high levels of molecules important for survival but prone to precipitation in poikilotherms (their body temperature can vary considerably) needs a companion mechanism to prevent the precipitation and here present, to our knowledge, the first example. Such a combination of trehalose and AFPs also provides a novel approach for cold protection and for trehalose crystallization inhibition in industrial applications. PMID:27226297

  3. Re-evaluation of a bacterial antifreeze protein as an adhesin with ice-binding activity.

    Directory of Open Access Journals (Sweden)

    Shuaiqi Guo

    Full Text Available A novel role for antifreeze proteins (AFPs may reside in an exceptionally large 1.5-MDa adhesin isolated from an Antarctic Gram-negative bacterium, Marinomonas primoryensis. MpAFP was purified from bacterial lysates by ice adsorption and gel electrophoresis. We have previously reported that two highly repetitive sequences, region II (RII and region IV (RIV, divide MpAFP into five distinct regions, all of which require mM Ca(2+ levels for correct folding. Also, the antifreeze activity is confined to the 322-residue RIV, which forms a Ca(2+-bound beta-helix containing thirteen Repeats-In-Toxin (RTX-like repeats. RII accounts for approximately 90% of the mass of MpAFP and is made up of ∼120 tandem 104-residue repeats. Because these repeats are identical in DNA sequence, their number was estimated here by pulsed-field gel electrophoresis. Structural homology analysis by the Protein Homology/analogY Recognition Engine (Phyre2 server indicates that the 104-residue RII repeat adopts an immunoglobulin beta-sandwich fold that is typical of many secreted adhesion proteins. Additional RTX-like repeats in RV may serve as a non-cleavable signal sequence for the type I secretion pathway. Immunodetection shows both repeated regions are uniformly distributed over the cell surface. We suggest that the development of an AFP-like domain within this adhesin attached to the bacterial outer surface serves to transiently bind the host bacteria to ice. This association would keep the bacteria within the upper reaches of the water column where oxygen and nutrients are potentially more abundant. This novel envirotactic role would give AFPs a third function, after freeze avoidance and freeze tolerance: that of transiently binding an organism to ice.

  4. The mysteries of memory effect and its elimination with antifreeze proteins

    Energy Technology Data Exchange (ETDEWEB)

    Walker, V.; Gordienko, R.; Kuiper, M.; Huva, E.; Wu, Z. [Queen' s Univ., Kingston, ON (Canada). Dept. of Biology; Zeng, H.; Ripmeester, J. [Queen' s Univ., Kingston, ON (Canada). Dept. of Biology]|[National Research Council of Canada, Ottawa, ON (Canada). Steacie Inst. for Molecular Sciences

    2008-07-01

    With the decline in easily accessible and conventional hydrocarbon supplies, exploration will focus on hydrocarbons in deep offshore waters, in permafrost or in crystalline water as gas hydrates. Crystallization of water or water-encaged gas molecules takes place when nuclei reach a critical size, but the crystal growth may be inhibited by certain antifreeze proteins (AFPs). In this study, the authors hypothesized that the crystal lattice of gas hydrates may act as an alternative for substrate antifreeze proteins (AFPs). AFP-mediated inhibition of ice and clathrate hydrate crystallization was examined. Since the AFPs had a notable ability to eliminate the memory effect (ME) or the faster reformation of clathrate hydrates after melting, the authors were prompted to examine heterogeneous nucleation. Silica, served as a model nucleator hydrophilic surface. Quartz crystal microbalance-dissipation (QCM-D) experiments showed that an active AFP was tightly adsorbed to the silica surface. However, polyvinylpyrrolidone (PVP) and polyvinylcaprolactam (PVCap), 2 commercial hydrate kinetic inhibitors that do not eliminate ME, were not as tightly adsorbed. A mutant AFP inhibited tetrahydrofuran clathrate hydrate growth, but not ME. QCM-D analysis showed that adsorption of the mutant AFP was more similar to PVCap than the active AFP. It was concluded that although there is no evidence for memory in ice reformation, the crystallization of ice and hydrates, and the elimination of the more rapid recrystallization of hydrates, can be mediated by the same proteins. The properties of adsorbed layers can be effectively monitored by QCM-D. These study results provided useful information about the inhibition mechanism of heterogeneous nucleation of clathrate hydrate. The technique facilitates the screening of potential low dose hydrate inhibitors and residues in AFPs that are involved in silica adsorption. 24 refs., 1 tab., 4 figs.

  5. Antifreeze Activity of Xylomannan from the Mycelium and Fruit Body of Flammulina velutipes.

    Science.gov (United States)

    Kawahara, Hidehisa; Matsuda, Yoshiyuki; Sakaguchi, Takuya; Arai, Naoki; Koide, Yoshihide

    2016-01-01

    An identified class of antifreeze, a xylomannan-based thermal hysteresis (TH)-producing glycolipid, has been discovered from diverse taxa, including plants, insects, and amphibians. We isolated xylomannan from the mycelium and fruit body of the basidiomycete Flammulina velutipes using successive hot extraction with water, 2% and 25% aqueous KOH, and gel filtration chromatography. The xylomannan from the fruit body had a recrystallization inhibiting (RI) activity (RI=0.44) at 0.5 mg/mL. The dried weight yield of the fruit body (7.7×10(-2)%, w/w) was higher than that of the mycelium. Although the purified xylomannan from both soures were composed of mannose and xylose in a 2 : 1 molar ratio, the molecular weight of the xylomannan from the mycelium and fruit body was 320,000 and 240,000, respectively. The RI activity of mycelial xylomannan was higher than that from the fruit body (RI=0.57) at 45 µg/mL. Although this RI activity was able to remain constant after exposure to various conditions, we confirmed that the decrease of RI activity was stimulated by the decrease of molecular weight that was caused by heating during the alkaline condition. The survival rate of the CHO cells at -20℃ for two days increased to 97% due to the addition of 20 µg/mL of purified xylomannan. This was the first report to indicate that xylomannan from the mycelium of Flammulina velutipes had a high level of ice recrystallization inhibiting activity like antifreeze proteins from plants and had rhe potential to become a new material for cell storage. PMID:27667520

  6. Influence of Block Copolymerization on the Antifreeze Protein Mimetic Ice Recrystallization Inhibition Activity of Poly(vinyl alcohol).

    Science.gov (United States)

    Congdon, Thomas R; Notman, Rebecca; Gibson, Matthew I

    2016-09-12

    Antifreeze (glyco) proteins are produced by many cold-acclimatized species to enable them to survive subzero temperatures. These proteins have multiple macroscopic effects on ice crystal growth which makes them appealing for low-temperature applications-from cellular cryopreservation to food storage. Poly(vinyl alcohol) has remarkable ice recrystallization inhibition activity, but its mode of action is uncertain as is the extent at which it can be incorporated into other high-order structures. Here the synthesis and characterization of well-defined block copolymers containing poly(vinyl alcohol) and poly(vinylpyrrolidone) by RAFT/MADIX polymerization is reported, as new antifreeze protein mimetics. The effect of adding a large second hydrophilic block is studied across a range of compositions, and it is found to be a passive component in ice recrystallization inhibition assays, enabling retention of all activity. In the extreme case, a block copolymer with only 10% poly(vinyl alcohol) was found to retain all activity, where statistical copolymers of PVA lose all activity with very minor changes to composition. These findings present a new method to increase the complexity of antifreeze protein mimetic materials, while retaining activity, and also to help understand the underlying mechanisms of action.

  7. Antifreeze (glyco)protein mimetic behavior of poly(vinyl alcohol): detailed structure ice recrystallization inhibition activity study.

    Science.gov (United States)

    Congdon, Thomas; Notman, Rebecca; Gibson, Matthew I

    2013-05-13

    This manuscript reports a detailed study on the ability of poly(vinyl alcohol) to act as a biomimetic surrogate for antifreeze(glyco)proteins, with a focus on the specific property of ice-recrystallization inhibition (IRI). Despite over 40 years of study, the underlying mechanisms that govern the action of biological antifreezes are still poorly understood, which is in part due to their limited availability and challenging synthesis. Poly(vinyl alcohol) (PVA) has been shown to display remarkable ice recrystallization inhibition activity despite its major structural differences to native antifreeze proteins. Here, controlled radical polymerization is used to synthesize well-defined PVA, which has enabled us to obtain the first quantitative structure-activity relationships, to probe the role of molecular weight and comonomers on IRI activity. Crucially, it was found that IRI activity is "switched on" when the polymer chain length increases from 10 and 20 repeat units. Substitution of the polymer side chains with hydrophilic or hydrophobic units was found to diminish activity. Hydrophobic modifications to the backbone were slightly more tolerated than side chain modifications, which implies an unbroken sequence of hydroxyl units is necessary for activity. These results highlight that, although hydrophobic domains are key components of IRI activity, the random inclusion of addition hydrophobic units does not guarantee an increase in activity and that the actual polymer conformation is important.

  8. Expression of a Carrot 36 kD Antifreeze Protein Gene Improves Cold Stress Tolerance in Transgenic Tobacco

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Antifreeze proteins (AFPs) enable organisms to survive under cold conditions, and have great potential in improving cold tolerance of cold-sensitive plants. In order to determine whether expression of the carrot 36 kD antifreeze protein gene confers improved cold-resistant properties to plant tissues, we tried to obtain transgenic tobacco plants which expressed the antifreeze protein. Cold, salt, and drought induced promoter Prd29A was cloned using PCR from Arabidopsis. Two plant expression vectors based on pBI121 were constructed with CaMV35S:AFP and Prd29A:AFP. Tobacco plantlets were transformed by Agrobacterium-medicated transformation. PCR and Southern blotting demonstrated that the carrot 36 kD afp gene was successfully integrated into the genomes of transformed plantlets. The expression of the afp gene in transgenic plants led to improved tolerance to cold stress.However, the use of the strong constitutive 35S cauliflower mosaic virus (CaMV) promoter to drive expression of afp also resulted in growth retardation under normal growing conditions. In contrast, the expression of afp driven by the stress-inducible Prd29A promoter from Arabidopsis gave rise to minimal effects on plant growth while providing an increased tolerance to cold stress condition (2℃). The results demonstrated the prospect of using Prd29A-AFP transgenic plants in cold-stressed conditions that will in turn benefit agriculture.

  9. Solution conformation of C-linked antifreeze glycoprotein analogues and modulation of ice recrystallization.

    Science.gov (United States)

    Tam, Roger Y; Rowley, Christopher N; Petrov, Ivan; Zhang, Tianyi; Afagh, Nicholas A; Woo, Tom K; Ben, Robert N

    2009-11-01

    Antifreeze glycoproteins (AFGPs) are a unique class of proteins that are found in many organisms inhabiting subzero environments and ensure their survival by preventing ice growth in vivo. During the last several years, our laboratory has synthesized functional C-linked AFGP analogues (3 and 5) that possess custom-tailored antifreeze activity suitable for medical, commercial, and industrial applications. These compounds are potent inhibitors of ice recrystallization and do not exhibit thermal hysteresis. The current study explores how changes in the length of the amide-containing side chain between the carbohydrate moiety and the polypeptide backbone in 5 influences ice recrystallization inhibition (IRI) activity. Analogue 5 (n = 3, where n is the number of carbons in the side chain) was a potent inhibitor of ice recrystallization, while 4, 6, and 7 (n = 4, 2, and 1, respectively) exhibited no IRI activity. The solution conformation of the polypeptide backbone in C-linked AFGP analogues 4-7 was examined using circular dichroism (CD) spectroscopy. The results suggested that all of the analogues exhibit a random coil conformation in solution and that the dramatic increase in IRI activity observed with 5 is not due to a change in long-range solution conformation. Variable-temperature (1)H NMR studies on truncated analogues 26-28 failed to elucidate the presence of persistent intramolecular bonds between the amide in the side chain and the peptide backbone. Molecular dynamics simulations performed on these analogues also failed to show persistent intramolecular hydrogen bonds. However, the simulations did indicate that the side chain of IRI-active analogue 26 (n = 3) adopts a unique short-range solution conformation in which it is folded back onto the peptide backbone, orienting the more hydrophilic face of the carbohydrate moiety away from the bulk solvent. In contrast, the solution conformation of IRI-inactive analogues 25, 27, and 28 had fully extended side chains

  10. Production of a recombinant type 1 antifreeze protein analogue by L. lactis and its applications on frozen meat and frozen dough.

    Science.gov (United States)

    Yeh, Chuan-Mei; Kao, Bi-Yu; Peng, Hsuan-Jung

    2009-07-22

    In this study, a novel recombinant type I antifreeze protein analogue (rAFP) was produced and secreted by Lactococcus lactis, a food-grade microorganism of major commercial importance. Antifreeze proteins are potent cryogenic protection agents for the cryopreservation of food and pharmaceutical materials. A food-grade expression and fermentation system (BSE- and antibiotic-free) for the production and secretion of high levels of rAFP was developed. Lyophilized, crude rAFP produced by L. lactis was tested in a frozen meat and frozen dough processing model. The frozen meat treated with the antifreeze protein showed less drip loss, less protein loss, and a high score on juiciness by sensory evaluation. Frozen dough treated with the rAFP showed better fermentation capacity than untreated frozen dough. Breads baked from frozen dough treated with rAFP acquired the same consumer acceptance as fresh bread. PMID:19545118

  11. Determining the ice-binding planes of antifreeze proteins by fluorescence-based ice plane affinity.

    Science.gov (United States)

    Basu, Koli; Garnham, Christopher P; Nishimiya, Yoshiyuki; Tsuda, Sakae; Braslavsky, Ido; Davies, Peter

    2014-01-15

    Antifreeze proteins (AFPs) are expressed in a variety of cold-hardy organisms to prevent or slow internal ice growth. AFPs bind to specific planes of ice through their ice-binding surfaces. Fluorescence-based ice plane affinity (FIPA) analysis is a modified technique used to determine the ice planes to which the AFPs bind. FIPA is based on the original ice-etching method for determining AFP-bound ice-planes. It produces clearer images in a shortened experimental time. In FIPA analysis, AFPs are fluorescently labeled with a chimeric tag or a covalent dye then slowly incorporated into a macroscopic single ice crystal, which has been preformed into a hemisphere and oriented to determine the a- and c-axes. The AFP-bound ice hemisphere is imaged under UV light to visualize AFP-bound planes using filters to block out nonspecific light. Fluorescent labeling of the AFPs allows real-time monitoring of AFP adsorption into ice. The labels have been found not to influence the planes to which AFPs bind. FIPA analysis also introduces the option to bind more than one differently tagged AFP on the same single ice crystal to help differentiate their binding planes. These applications of FIPA are helping to advance our understanding of how AFPs bind to ice to halt its growth and why many AFP-producing organisms express multiple AFP isoforms.

  12. Antifreeze proteins in the primary urine of larvae of the beetle Dendroides canadensis.

    Science.gov (United States)

    Nickell, Philip K; Sass, Sandra; Verleye, Dawn; Blumenthal, Edward M; Duman, John G

    2013-05-01

    To avoid freezing while overwintering beneath the bark of fallen trees, Dendroides canadensis (Coleoptera: Pyrochroidae) larvae produce a family of antifreeze proteins (DAFPs) that are transcribed in specific tissues and have specific compartmental fates. DAFPs and associated thermal hysteresis activity (THA) have been shown previously in hemolymph and midgut fluid, but the presence of DAFPs has not been explored in primary urine, a potentially important site that can contain endogenous ice-nucleating compounds that could induce freezing. A maximum mean THA of 2.65±0.33°C was observed in primary urine of winter-collected D. canadensis larvae. THA in primary urine increased significantly through autumn, peaked in the winter and decreased through spring to levels of 0.2-0.3°C in summer, in a pattern similar to that of hemolymph and midgut fluid. THA was also found in hindgut fluid and excreted rectal fluid, suggesting that these larvae not only concentrate AFPs in the hindgut, but also excrete AFPs from the rectal cavity. Based on dafp transcripts isolated from Malpighian tubule epithelia, cDNAs were cloned and sequenced, identifying the presence of transcripts encoding 24 DAFP isoforms. Six of these Malpighian tubule DAFPs were known previously, but 18 are new. We also provide functional evidence that DAFPs can inhibit ice nucleators present in insect primary urine. This is potentially critical because D. canadensis larvae die if frozen, and therefore ice formation in any body fluid, including the urine, would be lethal.

  13. Low thermodynamic but high kinetic stability of an antifreeze protein from Rhagium mordax.

    Science.gov (United States)

    Friis, Dennis S; Johnsen, Johannes L; Kristiansen, Erlend; Westh, Peter; Ramløv, Hans

    2014-06-01

    The equilibrium heat stability and the kinetic heat tolerance of a recombinant antifreeze protein (AFP) from the beetle Rhagium mordax (RmAFP1) are studied through differential scanning calorimetry and circular dichroism spectroscopy. In contrast to other insect AFPs studied with this respect, the RmAFP1 has only one disulfide bridge. The melting temperature, Tm , of the protein is determined to be 28.5°C (pH 7.4), which is much lower than most of those reported for AFPs or globular proteins in general. Despite its low melting temperature, both biophysical and activity measurements show that the protein almost completely refolds into the native state after repeated exposure of 70°C. RmAFP1 thus appears to be kinetically stable even far above its melting temperature. Thermodynamically, the insect AFPs seem to be dividable in three groups, relating to their content of disulfide bridges and widths of the ice binding motifs; high melting temperature AFPs (high disulfide content, TxT motifs), low melting temperature but high refolding capability AFPs (one disulfide bridge, TxTxTxT motifs) and irreversibly unfolded AFPs at low temperatures (no disulfide bridges, TxTxTxTxT motifs). The property of being able to cope with high temperature exposures may appear peculiar for proteins which strictly have their effect at subzero temperatures. Different aspects of this are discussed.

  14. Dendrimer-Linked Antifreeze Proteins Have Superior Activity and Thermal Recovery.

    Science.gov (United States)

    Stevens, Corey A; Drori, Ran; Zalis, Shiran; Braslavsky, Ido; Davies, Peter L

    2015-09-16

    By binding to ice, antifreeze proteins (AFPs) depress the freezing point of a solution and inhibit ice recrystallization if freezing does occur. Previous work showed that the activity of an AFP was incrementally increased by fusing it to another protein. Even larger increases in activity were achieved by doubling the number of ice-binding sites by dimerization. Here, we have combined the two strategies by linking multiple outward-facing AFPs to a dendrimer to significantly increase both the size of the molecule and the number of ice-binding sites. Using a heterobifunctional cross-linker, we attached between 6 and 11 type III AFPs to a second-generation polyamidoamine (G2-PAMAM) dendrimer with 16 reactive termini. This heterogeneous sample of dendrimer-linked type III constructs showed a greater than 4-fold increase in freezing point depression over that of monomeric type III AFP. This multimerized AFP was particularly effective at ice recrystallization inhibition activity, likely because it can simultaneously bind multiple ice surfaces. Additionally, attachment to the dendrimer has afforded the AFP superior recovery from heat denaturation. Linking AFPs together via polymers can generate novel reagents for controlling ice growth and recrystallization. PMID:26267368

  15. Structure and evolutionary origin of Ca(2+-dependent herring type II antifreeze protein.

    Directory of Open Access Journals (Sweden)

    Yang Liu

    Full Text Available In order to survive under extremely cold environments, many organisms produce antifreeze proteins (AFPs. AFPs inhibit the growth of ice crystals and protect organisms from freezing damage. Fish AFPs can be classified into five distinct types based on their structures. Here we report the structure of herring AFP (hAFP, a Ca(2+-dependent fish type II AFP. It exhibits a fold similar to the C-type (Ca(2+-dependent lectins with unique ice-binding features. The 1.7 A crystal structure of hAFP with bound Ca(2+ and site-directed mutagenesis reveal an ice-binding site consisting of Thr96, Thr98 and Ca(2+-coordinating residues Asp94 and Glu99, which initiate hAFP adsorption onto the [10-10] prism plane of the ice lattice. The hAFP-ice interaction is further strengthened by the bound Ca(2+ through the coordination with a water molecule of the ice lattice. This Ca(2+-coordinated ice-binding mechanism is distinct from previously proposed mechanisms for other AFPs. However, phylogenetic analysis suggests that all type II AFPs evolved from the common ancestor and developed different ice-binding modes. We clarify the evolutionary relationship of type II AFPs to sugar-binding lectins.

  16. Structural Basis for the Inhibition of Gas Hydrates by α-Helical Antifreeze Proteins.

    Science.gov (United States)

    Sun, Tianjun; Davies, Peter L; Walker, Virginia K

    2015-10-20

    Kinetic hydrate inhibitors (KHIs) are used commercially to inhibit gas hydrate formation and growth in pipelines. However, improvement of these polymers has been constrained by the lack of verified molecular models. Since antifreeze proteins (AFPs) act as KHIs, we have used their solved x-ray crystallographic structures in molecular modeling to explore gas hydrate inhibition. The internal clathrate water network of the fish AFP Maxi, which extends to the protein's outer surface, is remarkably similar to the {100} planes of structure type II (sII) gas hydrate. The crystal structure of this water web has facilitated the construction of in silico models for Maxi and type I AFP binding to sII hydrates. Here, we have substantiated our models with experimental evidence of Maxi binding to the tetrahydrofuran sII model hydrate. Both in silico and experimental evidence support the absorbance-inhibition mechanism proposed for KHI binding to gas hydrates. Based on the Maxi crystal structure we suggest that the inhibitor adsorbs to the gas hydrate lattice through the same anchored clathrate water mechanism used to bind ice. These results will facilitate the rational design of a next generation of effective green KHIs for the petroleum industry to ensure safe and efficient hydrocarbon flow. PMID:26488661

  17. Effect of antifreeze glycoprotein 8 supplementation during vitrification on the developmental competence of bovine oocytes.

    Science.gov (United States)

    Liang, Shuang; Yuan, Bao; Kwon, Jeong-Woo; Ahn, Mija; Cui, Xiang-Shun; Bang, Jeong Kyu; Kim, Nam-Hyung

    2016-07-15

    The purpose of this study was to investigate the effect of antifreeze glycoprotein 8 (AFGP8) supplementation during vitrification on the survival, fertilization, and embryonic development of bovine oocytes and the underlying molecular mechanism(s). Survival, fertilization, early embryonic development, apoptosis, DNA double-strand breaks, reactive oxygen species levels, meiotic cytoskeleton assembly, chromosome alignment, and energy status of mitochondria were measured in the present experiments. Compared with that in the nonsupplemented group; survival, monospermy, blastocyst formation rates, and blastomere counts were significantly higher in the AFGP8-supplemented animals. Oocytes of the latter group also presented fewer double-strand breaks and lower cathepsin B and caspase activities. Rates of normal spindle organization and chromosome alignment, actin filament impairment, and mitochondrial distribution were significantly higher in the AFGP8-supplemented group. In addition, intracellular reactive oxygen species levels significantly decreased in the AFGP8-supplemented groups, maintaining a higher ΔΨm than that in the nonsupplemented group. Taken together, these results indicated that supplementation with AFGP8 during vitrification has a protective effect on bovine oocytes against chilling injury. PMID:26948296

  18. Dendrimer-Linked Antifreeze Proteins Have Superior Activity and Thermal Recovery.

    Science.gov (United States)

    Stevens, Corey A; Drori, Ran; Zalis, Shiran; Braslavsky, Ido; Davies, Peter L

    2015-09-16

    By binding to ice, antifreeze proteins (AFPs) depress the freezing point of a solution and inhibit ice recrystallization if freezing does occur. Previous work showed that the activity of an AFP was incrementally increased by fusing it to another protein. Even larger increases in activity were achieved by doubling the number of ice-binding sites by dimerization. Here, we have combined the two strategies by linking multiple outward-facing AFPs to a dendrimer to significantly increase both the size of the molecule and the number of ice-binding sites. Using a heterobifunctional cross-linker, we attached between 6 and 11 type III AFPs to a second-generation polyamidoamine (G2-PAMAM) dendrimer with 16 reactive termini. This heterogeneous sample of dendrimer-linked type III constructs showed a greater than 4-fold increase in freezing point depression over that of monomeric type III AFP. This multimerized AFP was particularly effective at ice recrystallization inhibition activity, likely because it can simultaneously bind multiple ice surfaces. Additionally, attachment to the dendrimer has afforded the AFP superior recovery from heat denaturation. Linking AFPs together via polymers can generate novel reagents for controlling ice growth and recrystallization.

  19. Antifreeze Peptides and Glycopeptides, and Their Derivatives: Potential Uses in Biotechnology

    Directory of Open Access Journals (Sweden)

    Hyun-Cheol Kim

    2013-06-01

    Full Text Available Antifreeze proteins (AFPs and glycoproteins (AFGPs, collectively called AF(GPs, constitute a diverse class of proteins found in various Arctic and Antarctic fish, as well as in amphibians, plants, and insects. These compounds possess the ability to inhibit the formation of ice and are therefore essential to the survival of many marine teleost fishes that routinely encounter sub-zero temperatures. Owing to this property, AF(GPs have potential applications in many areas such as storage of cells or tissues at low temperature, ice slurries for refrigeration systems, and food storage. In contrast to AFGPs, which are composed of repeated tripeptide units (Ala-Ala-Thrn with minor sequence variations, AFPs possess very different primary, secondary, and tertiary structures. The isolation and purification of AFGPs is laborious, costly, and often results in mixtures, making characterization difficult. Recent structural investigations into the mechanism by which linear and cyclic AFGPs inhibit ice crystallization have led to significant progress toward the synthesis and assessment of several synthetic mimics of AFGPs. This review article will summarize synthetic AFGP mimics as well as current challenges in designing compounds capable of mimicking AFGPs. It will also cover our recent efforts in exploring whether peptoid mimics can serve as structural and functional mimics of native AFGPs.

  20. Modeling the Influence of Antifreeze Proteins on Three-Dimensional Ice Crystal Melt Shapes using a Geometric Approach

    CERN Document Server

    Liu, Jun Jie; Dolev, Maya Bar; Celik, Yeliz; Wettlaufer, J S; Braslavsky, Ido

    2012-01-01

    The melting of pure axisymmetric ice crystals has been described previously by us within the framework of so-called geometric crystal growth. Nonequilibrium ice crystal shapes evolving in the presence of hyperactive antifreeze proteins (hypAFPs) are experimentally observed to assume ellipsoidal geometries ("lemon" or "rice" shapes). To analyze such shapes we harness the underlying symmetry of hexagonal ice Ih and extend two-dimensional geometric models to three-dimensions to reproduce the experimental dissolution process. The geometrical model developed will be useful as a quantitative test of the mechanisms of interaction between hypAFPs and ice.

  1. AccaDueO - Solar heating system without antifreeze; AccaDueO - Solaranlage ohne Frostschutzmittel - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Engeler, L.; Salerno, B.

    2003-12-15

    This illustrated final report for the Swiss Federal Office of Energy (SFOE) describes a solar collector system that uses a heat transfer fluid without antifreeze additives. The so-called 'drain-back' system supplies heat for heating and hot water preparation in a three-family house in Waldenburg, Switzerland, together with a wood-fired boiler. The results of measurements made on the collectors and the storage tank are presented in tabular and graphical form and discussed. The opinions of experts, inhabitants and the general public are noted.

  2. Revealing Surface Waters on an Antifreeze Protein by Fusion Protein Crystallography Combined with Molecular Dynamic Simulations.

    Science.gov (United States)

    Sun, Tianjun; Gauthier, Sherry Y; Campbell, Robert L; Davies, Peter L

    2015-10-01

    Antifreeze proteins (AFPs) adsorb to ice through an extensive, flat, relatively hydrophobic surface. It has been suggested that this ice-binding site (IBS) organizes surface waters into an ice-like clathrate arrangement that matches and fuses to the quasi-liquid layer on the ice surface. On cooling, these waters join the ice lattice and freeze the AFP to its ligand. Evidence for the generality of this binding mechanism is limited because AFPs tend to crystallize with their IBS as a preferred protein-protein contact surface, which displaces some bound waters. Type III AFP is a 7 kDa globular protein with an IBS made up two adjacent surfaces. In the crystal structure of the most active isoform (QAE1), the part of the IBS that docks to the primary prism plane of ice is partially exposed to solvent and has clathrate waters present that match this plane of ice. The adjacent IBS, which matches the pyramidal plane of ice, is involved in protein-protein crystal contacts with few surface waters. Here we have changed the protein-protein contacts in the ice-binding region by crystallizing a fusion of QAE1 to maltose-binding protein. In this 1.9 Å structure, the IBS that fits the pyramidal plane of ice is exposed to solvent. By combining crystallography data with MD simulations, the surface waters on both sides of the IBS were revealed and match well with the target ice planes. The waters on the pyramidal plane IBS were loosely constrained, which might explain why other isoforms of type III AFP that lack the prism plane IBS are less active than QAE1. The AFP fusion crystallization method can potentially be used to force the exposure to solvent of the IBS on other AFPs to reveal the locations of key surface waters.

  3. Revealing Surface Waters on an Antifreeze Protein by Fusion Protein Crystallography Combined with Molecular Dynamic Simulations.

    Science.gov (United States)

    Sun, Tianjun; Gauthier, Sherry Y; Campbell, Robert L; Davies, Peter L

    2015-10-01

    Antifreeze proteins (AFPs) adsorb to ice through an extensive, flat, relatively hydrophobic surface. It has been suggested that this ice-binding site (IBS) organizes surface waters into an ice-like clathrate arrangement that matches and fuses to the quasi-liquid layer on the ice surface. On cooling, these waters join the ice lattice and freeze the AFP to its ligand. Evidence for the generality of this binding mechanism is limited because AFPs tend to crystallize with their IBS as a preferred protein-protein contact surface, which displaces some bound waters. Type III AFP is a 7 kDa globular protein with an IBS made up two adjacent surfaces. In the crystal structure of the most active isoform (QAE1), the part of the IBS that docks to the primary prism plane of ice is partially exposed to solvent and has clathrate waters present that match this plane of ice. The adjacent IBS, which matches the pyramidal plane of ice, is involved in protein-protein crystal contacts with few surface waters. Here we have changed the protein-protein contacts in the ice-binding region by crystallizing a fusion of QAE1 to maltose-binding protein. In this 1.9 Å structure, the IBS that fits the pyramidal plane of ice is exposed to solvent. By combining crystallography data with MD simulations, the surface waters on both sides of the IBS were revealed and match well with the target ice planes. The waters on the pyramidal plane IBS were loosely constrained, which might explain why other isoforms of type III AFP that lack the prism plane IBS are less active than QAE1. The AFP fusion crystallization method can potentially be used to force the exposure to solvent of the IBS on other AFPs to reveal the locations of key surface waters. PMID:26371748

  4. Lateral transfer of a lectin-like antifreeze protein gene in fishes.

    Directory of Open Access Journals (Sweden)

    Laurie A Graham

    Full Text Available Fishes living in icy seawater are usually protected from freezing by endogenous antifreeze proteins (AFPs that bind to ice crystals and stop them from growing. The scattered distribution of five highly diverse AFP types across phylogenetically disparate fish species is puzzling. The appearance of radically different AFPs in closely related species has been attributed to the rapid, independent evolution of these proteins in response to natural selection caused by sea level glaciations within the last 20 million years. In at least one instance the same type of simple repetitive AFP has independently originated in two distant species by convergent evolution. But, the isolated occurrence of three very similar type II AFPs in three distantly related species (herring, smelt and sea raven cannot be explained by this mechanism. These globular, lectin-like AFPs have a unique disulfide-bonding pattern, and share up to 85% identity in their amino acid sequences, with regions of even higher identity in their genes. A thorough search of current databases failed to find a homolog in any other species with greater than 40% amino acid sequence identity. Consistent with this result, genomic Southern blots showed the lectin-like AFP gene was absent from all other fish species tested. The remarkable conservation of both intron and exon sequences, the lack of correlation between evolutionary distance and mutation rate, and the pattern of silent vs non-silent codon changes make it unlikely that the gene for this AFP pre-existed but was lost from most branches of the teleost radiation. We propose instead that lateral gene transfer has resulted in the occurrence of the type II AFPs in herring, smelt and sea raven and allowed these species to survive in an otherwise lethal niche.

  5. Smelt was the likely beneficiary of an antifreeze gene laterally transferred between fishes

    Directory of Open Access Journals (Sweden)

    Graham Laurie A

    2012-09-01

    Full Text Available Abstract Background Type II antifreeze protein (AFP from the rainbow smelt, Osmerus mordax, is a calcium-dependent C-type lectin homolog, similar to the AFPs from herring and sea raven. While C-type lectins are ubiquitous, type II AFPs are only found in a few species in three widely separated branches of teleost fishes. Furthermore, several other non-homologous AFPs are found in intervening species. We have previously postulated that this sporadic distribution has resulted from lateral gene transfer. The alternative hypothesis, that the AFP evolved from a lectin present in a shared ancestor and that this gene was lost in most species, is not favored because both the exon and intron sequences are highly conserved. Results Here we have sequenced and annotated a 160 kb smelt BAC clone containing a centrally-located AFP gene along with 14 other genes. Quantitative PCR indicates that there is but a single copy of this gene within the smelt genome, which is atypical for fish AFP genes. The corresponding syntenic region has been identified and searched in a number of other species and found to be devoid of lectin or AFP sequences. Unlike the introns of the AFP gene, the intronic sequences of the flanking genes are not conserved between species. As well, the rate and pattern of mutation in the AFP gene are radically different from those seen in other smelt and herring genes. Conclusions These results provide stand-alone support for an example of lateral gene transfer between vertebrate species. They should further inform the debate about genetically modified organisms by showing that gene transfer between ‘higher’ eukaryotes can occur naturally. Analysis of the syntenic regions from several fishes strongly suggests that the smelt acquired the AFP gene from the herring.

  6. In silico characterization of antifreeze proteins using computational tools and servers

    Indian Academy of Sciences (India)

    K Sivakumar; S Balaji; Gangaradhakrishnan

    2007-09-01

    In this paper, seventeen different fish Antifreeze Proteins (AFPs) retrieved from Swiss-Prot database are analysed and characterized using In silico tools. Primary structure analysis shows that most of the AFPs are hydrophobic in nature due to the high content of non-polar residues. The presence of 11 cysteines in the rainbow smelt fish and sea raven fish AFPs infer that these proteins may form disulphide (SS) bonds, which are regarded as a positive factor for stability. The aliphatic index computed by Ex-Pasy’s ProtParam infers that AFPs may be stable for a wide range of temperature. Secondary structure analysis shows that most of the fish AFPs have predominant α-helical structures and rest of the AFPs have mixed secondary structure. The very high coil structural content of rainbow smelt fish and sea raven fish AFPs are due to the rich content of more flexible glycine and hydrophobic proline amino acids. Proline has a special property of creating kinks in polypetide chains and disrupting ordered secondary structure. SOSUI server predicts one transmembrane region in winter flounder fish and atlantic cod and two transmembrane regions in yellowtail flounder fish AFP. The predicted transmembrane regions were visualized and analysed using helical wheel plots generated by EMBOSS pepwheel tool. The presence of disulphide (SS) bonds in the AFPs Q01758 and P05140 are predicted by CYS_REC tool and also identified from the three-dimensional structure using Rasmol tool. The disulphide bonds identified from the three-dimensional structure using the Rasmol tool might be correct as the evaluation parameters are within the acceptable limits for the modelled 3D structures.

  7. Purification, crystal structure determination and functional characterization of type III antifreeze proteins from the European eelpout Zoarces viviparus

    DEFF Research Database (Denmark)

    Wilkens, Casper; Poulsen, Jens-Christian Navarro; Ramløv, Hans;

    2014-01-01

    Antifreeze proteins (AFPs) are essential components of many organisms adaptation to cold temperatures. Fish type III AFPs are divided into two groups, SP isoforms being much less active than QAE1 isoforms. Two type III AFPs from Zoarces viviparus, a QAE1 (ZvAFP13) and an SP (ZvAFP6) isoform...

  8. Expression, purification and activity determination of the beetle tenebrio molitor antifreeze protein afp84c in escherichia coli

    International Nuclear Information System (INIS)

    Summary: A cDNA encoding antifreeze protein (AFP84c) was cloned by RT-PCR from the larva of the yellow mealworm Tenebrio molitor. The coding fragment of 252 bp encodes a protein of 84 amino acid residues and was fused to the expression vectors pMAL-c2X and pMAL-p2X. The expression plasmids pMAL-c2X-afp84c and pMAL-p2X-afp84c were constructed and transformed into Escherischia coli strains TBI, respectively. Strategy of optimization of induction conditions were used for expression of the highly disulfide-bonded beta-helix-contained protein with the activity of antifreeze in pMALTM expression system. The target fusion protein was released from the cytoplasm and periplasm by sonication and cold osmotic shock procedure respectively. Recombinant AFP84c was purified by amylose affinity column. The purified target protein displayed a single band in SDS-PAGE. Expressed AFP84c exhibits to increase low temperature resistance of bacteria. (author)

  9. De novo DESIGN AND SYNTHESIS OF AN ICE-BINDING, DENDRIMERIC, POLYPEPTIDE BASED ON INSECT ANTIFREEZE PROTEINS

    Directory of Open Access Journals (Sweden)

    Ricardo Vera Bravo

    2011-12-01

    Full Text Available A new strategy is presented for the designand synthesis of peptides that exhibitice-binding and antifreeze activity. Apennant-type dendrimer polypeptidescaffold combining an α-helical backbonewith four short β-strand branches wassynthesized in solid phase using Fmocchemistry in a divergent approach. The51-residue dendrimer was characterizedby reverse phase high performance liquidchromatography, mass spectrometry andcircular dichroism. Each β-strand branchcontained three overlapping TXT aminoacid repeats, an ice-binding motif foundin the ice-binding face of the sprucebudworm (Choristoneura fumiferanaand beetle (Tenebrio molitor antifreezeproteins. Ice crystals in the presence ofthe polypeptide monomer displayed flat,hexagonal plate morphology, similar tothat produced by weakly active antifreezeproteins. An oxidized dimeric form of thedendrimer polypeptide also produced flathexagonal ice crystals and was capableof inhibiting ice crystal growth upontemperature reduction, a phenomenontermed thermal hysteresis, a definingproperty of antifreeze proteins. Linkageof the pennant-type dendrimer to a trifunctionalcascade-type polypeptideproduced a trimeric macromolecule thatgave flat hexagonal ice crystals withhigher thermal hysteresis activity thanthe dimer or monomer and an ice crystal burst pattern similar to that producedby samples containing insect antifreezeproteins. This macromolecule was alsocapable of inhibiting ice recrystallization.

  10. Structure of solvation water around the active and inactive regions of a type III antifreeze protein and its mutants of lowered activity

    Science.gov (United States)

    Grabowska, Joanna; Kuffel, Anna; Zielkiewicz, Jan

    2016-08-01

    Water molecules from the solvation shell of the ice-binding surface are considered important for the antifreeze proteins to perform their function properly. Herein, we discuss the problem whether the extent of changes of the mean properties of solvation water can be connected with the antifreeze activity of the protein. To this aim, the structure of solvation water of a type III antifreeze protein from Macrozoarces americanus (eel pout) is investigated. A wild type of the protein is used, along with its three mutants, with antifreeze activities equal to 54% or 10% of the activity of the native form. The solvation water of the ice-binding surface and the rest of the protein are analyzed separately. To characterize the structure of solvation shell, parameters describing radial and angular characteristics of the mutual arrangement of the molecules were employed. They take into account short-distance (first hydration shell) or long-distance (two solvation shells) effects. The obtained results and the comparison with the results obtained previously for a hyperactive antifreeze protein from Choristoneura fumiferana lead to the conclusion that the structure and amino acid composition of the active region of the protein evolved to achieve two goals. The first one is the modification of the properties of the solvation water. The second one is the geometrical adjustment of the protein surface to the specific crystallographic plane of ice. Both of these goals have to be achieved simultaneously in order for the protein to perform its function properly. However, they seem to be independent from one another in a sense that very small antifreeze activity does not imply that properties of water become different from the ones observed for the wild type. The proteins with significantly lower activity still modify the mean properties of solvation water in a right direction, in spite of the fact that the accuracy of the geometrical match with the ice lattice is lost because of the

  11. Research Progress in Antifreeze Proteins and Application in Food Industry%抗冻蛋白的研究进展及其在食品工业中的应用

    Institute of Scientific and Technical Information of China (English)

    汪少芸; 赵珺; 吴金鸿; 陈琳

    2011-01-01

    抗冻蛋白是一类具有热滞效应、冰晶形态效应和重结晶抑制效应的蛋白质,因其特殊的结构和功能,抗冻蛋白引起了研究人员的极大兴趣.探讨了近年来抗冻蛋白的研究进展,介绍了目前已知的抗冻蛋白的来源、特性、测定方法、基因结构及在食品工业中的应用.抗冻蛋白对冷冻食品有显著的品质改良功能,是未来冷冻食品工业中极具潜力的抗冻添加剂.%Antifreeze proteins (AFPs) are the thermal hysteresis proteins that have the ability to modify the growth and inhibit the recrystallization of the ice. Antifreeze proteins aroused great interests of many researchers due to its special structure and functions. In this article, the recent advance in antifreeze protein was reviewed, and the types, properties, measurements, gene structures of antifreeze protein, and its applications in food industry were introduced. The application trials indicated that antifreeze protein could significantly improve the qualities of frozen foods, which suggested the potential food additives of antifreeze protein in future frozen food industry.

  12. Low thermodynamic but high kinetic stability of an antifreeze protein from Rhagium mordax

    DEFF Research Database (Denmark)

    Friis, Dennis Steven; Johnsen, Johannes Lørup; Kristiansen, Erlend;

    2014-01-01

    The equilibrium heat stability and the kinetic heat tolerance of a recombinant antifreeze protein (AFP) from the beetle Rhagium mordax (RmAFP1) are studied through differential scanning calorimetry and circular dichroism spectroscopy. In contrast to other insect AFPs studied with this respect, the...... RmAFP1 has only one disulfide bridge. The melting temperature, Tm, of the protein is determined to be 28.5°C (pH 7.4), which is much lower than most of those reported for AFPs or globular proteins in general. Despite its low melting temperature, both biophysical and activity measurements show that...... the protein almost completely refolds into the native state after repeated exposure of 70°C. RmAFP1 thus appears to be kinetically stable even far above its melting temperature. Thermodynamically, the insect AFPs seem to be dividable in three groups, relating to their content of disulfide bridges and...

  13. Isolation and characterisation of sericin antifreeze peptides and molecular dynamics modelling of their ice-binding interaction.

    Science.gov (United States)

    Wu, Jinhong; Rong, Yuzhi; Wang, Zhengwu; Zhou, Yanfu; Wang, Shaoyun; Zhao, Bo

    2015-05-01

    This study aimed to isolate and characterise a novel sericin antifreeze peptide and investigate its ice-binding molecular mechanism. The thermal hysteresis activity of ice-binding sericin peptides (I-SP) was measured and their activity reached as high as 0.94 °C. A P4 fraction, with high hypothermia protective activity and inhibition activity of ice recrystallisation, was obtained from I-SP, and a purified sericin peptide, named SM-AFP, with the sequence of TTSPTNVSTT and a molecular weight of 1009.50 Da was then isolated from the P4 fraction. Treatment of Lactobacillus delbrueckii Subsp. bulgaricus LB340 LYO with 100 μg/ml synthetic SM-AFP led to 1.4-fold increased survival (p Sericin peptides could be developed into beneficial cryoprotectants and used in frozen food processing. PMID:25529728

  14. Effects of three different types of antifreeze proteins on mouse ovarian tissue cryopreservation and transplantation.

    Directory of Open Access Journals (Sweden)

    Jaewang Lee

    Full Text Available Ovarian tissue (OT cryopreservation is effective in preserving fertility in cancer patients who have concerns about fertility loss due to cancer treatment. However, the damage incurred at different steps during the cryopreservation procedure may cause follicular depletion; hence, preventing chilling injury would help maintain ovarian function.This study was designed to investigate the beneficial effects of different antifreeze proteins (AFPs on mouse ovarian tissue cryopreservation and transplantation.Ovaries were obtained from 5-week-old B6D2F1 mice, and each ovary was cryopreserved using two-step vitrification and four-step warming procedures. In Experiment I, ovaries were randomly allocated into fresh, vitrification control, and nine experimental groups according to the AFP type (FfIBP, LeIBP, type III and concentration (0.1, 1, 10 mg/mL used. After vitrification and warming, 5,790 ovarian follicles were evaluated using histology and TUNEL assays, and immunofluorescence for τH2AX and Rad51 was used to detect DNA double-strand breaks (DSBs and repair (DDR, respectively. In Experiment II, 20 mice were randomly divided into two groups: one where the vitrification and warming media were supplemented with 10 mg/mL LeIBP, and the other where media alone were used (control. Ovaries were then autotransplanted under both kidney capsules 7 days after vitrification together with the addition of 10 mg/mL LeIBP in the vitrification-warming media. After transplantation, the ovarian follicles, the percentage of apoptotic follicles, the extent of the CD31-positive area, and the serum FSH levels of the transplanted groups were compared.In Experiment I, the percentage of total grade 1 follicles was significantly higher in the 10 mg/mL LeIBP group than in the vitrification control, while all AFP-treated groups had significantly improved grade 1 primordial follicle numbers compared with those of the vitrification control. The number of apoptotic (TUNEL

  15. Antifreeze protein from freeze-tolerant grass has a beta-roll fold with an irregularly structured ice-binding site.

    Science.gov (United States)

    Middleton, Adam J; Marshall, Christopher B; Faucher, Frédérick; Bar-Dolev, Maya; Braslavsky, Ido; Campbell, Robert L; Walker, Virginia K; Davies, Peter L

    2012-03-01

    The grass Lolium perenne produces an ice-binding protein (LpIBP) that helps this perennial tolerate freezing by inhibiting the recrystallization of ice. Ice-binding proteins (IBPs) are also produced by freeze-avoiding organisms to halt the growth of ice and are better known as antifreeze proteins (AFPs). To examine the structural basis for the different roles of these two IBP types, we have solved the first crystal structure of a plant IBP. The 118-residue LpIBP folds as a novel left-handed beta-roll with eight 14- or 15-residue coils and is stabilized by a small hydrophobic core and two internal Asn ladders. The ice-binding site (IBS) is formed by a flat beta-sheet on one surface of the beta-roll. We show that LpIBP binds to both the basal and primary-prism planes of ice, which is the hallmark of hyperactive AFPs. However, the antifreeze activity of LpIBP is less than 10% of that measured for those hyperactive AFPs with convergently evolved beta-solenoid structures. Whereas these hyperactive AFPs have two rows of aligned Thr residues on their IBS, the equivalent arrays in LpIBP are populated by a mixture of Thr, Ser and Val with several side-chain conformations. Substitution of Ser or Val for Thr on the IBS of a hyperactive AFP reduced its antifreeze activity. LpIBP may have evolved an IBS that has low antifreeze activity to avoid damage from rapid ice growth that occurs when temperatures exceed the capacity of AFPs to block ice growth while retaining the ability to inhibit ice recrystallization.

  16. Ice-binding site of snow mold fungus antifreeze protein deviates from structural regularity and high conservation.

    Science.gov (United States)

    Kondo, Hidemasa; Hanada, Yuichi; Sugimoto, Hiroshi; Hoshino, Tamotsu; Garnham, Christopher P; Davies, Peter L; Tsuda, Sakae

    2012-06-12

    Antifreeze proteins (AFPs) are found in organisms ranging from fish to bacteria, where they serve different functions to facilitate survival of their host. AFPs that protect freeze-intolerant fish and insects from internal ice growth bind to ice using a regular array of well-conserved residues/motifs. Less is known about the role of AFPs in freeze-tolerant species, which might be to beneficially alter the structure of ice in or around the host. Here we report the 0.95-Å high-resolution crystal structure of a 223-residue secreted AFP from the snow mold fungus Typhula ishikariensis. Its main structural element is an irregular β-helix with six loops of 18 or more residues that lies alongside an α-helix. β-Helices have independently evolved as AFPs on several occasions and seem ideally structured to bind to several planes of ice, including the basal plane. A novelty of the β-helical fold is the nonsequential arrangement of loops that places the N- and C termini inside the solenoid of β-helical coils. The ice-binding site (IBS), which could not be predicted from sequence or structure, was located by site-directed mutagenesis to the flattest surface of the protein. It is remarkable for its lack of regularity and its poor conservation in homologs from psychrophilic diatoms and bacteria and other fungi.

  17. Molecular and quantum mechanical studies on the monomer recognition of a highly-regular β-helical antifreeze protein

    Institute of Scientific and Technical Information of China (English)

    YANG; Zuoyin; JIA; Zongchao; LIU; Ruozhuang; CHEN; Guangj

    2004-01-01

    The possible interaction models for an antifreeze protein from Tenebrio molitar (TmAFP) have been systematically studied using the methods of molecular mechanics, molecular dynamics and quantum chemistry. It is hoped that these approaches would provide insights into the nature of interaction between protein monomers through sampling a number of interaction possibilities and evaluating their interaction energies between two monomers in the course of recognition. The results derived from the molecular mechanics indicate that monomer's β-sheets would be involved in interaction area and the side chains on two β-faces can match each other at the two-dimensional level. The results from molecular mechanics and ONIOM methods show that the strongest interaction energy could be gained through the formation of H-bonds when the two β-sheets are involved in the interaction model. Furthermore, the calculation of DFT and analysis of van der Waals bond charge density confirm further that recognition between the two TCTs mainly depends on inter-molecular hydroxyls. Therefore, our results demonstrate that during the course of interaction the most favorable association of TmAFPs is via their β-sheets.

  18. Transcriptomic and proteomic analyses on the supercooling ability and mining of antifreeze proteins of the Chinese white wax scale insect.

    Science.gov (United States)

    Yu, Shu-Hui; Yang, Pu; Sun, Tao; Qi, Qian; Wang, Xue-Qing; Chen, Xiao-Ming; Feng, Ying; Liu, Bo-Wen

    2016-06-01

    The Chinese white wax scale insect, Ericerus pela, can survive at extremely low temperatures, and some overwintering individuals exhibit supercooling at temperatures below -30°C. To investigate the deep supercooling ability of E. pela, transcriptomic and proteomic analyses were performed to delineate the major gene and protein families responsible for the deep supercooling ability of overwintering females. Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that genes involved in the mitogen-activated protein kinase, calcium, and PI3K-Akt signaling pathways and pathways associated with the biosynthesis of soluble sugars, sugar alcohols and free amino acids were dominant. Proteins responsible for low-temperature stress, such as cold acclimation proteins, glycerol biosynthesis-related enzymes and heat shock proteins (HSPs) were identified. However, no antifreeze proteins (AFPs) were identified through sequence similarity search methods. A random forest approach identified 388 putative AFPs in the proteome. The AFP gene ep-afp was expressed in Escherichia coli, and the expressed protein exhibited a thermal hysteresis activity of 0.97°C, suggesting its potential role in the deep supercooling ability of E. pela.

  19. Transcriptomic and proteomic analyses on the supercooling ability and mining of antifreeze proteins of the Chinese white wax scale insect.

    Science.gov (United States)

    Yu, Shu-Hui; Yang, Pu; Sun, Tao; Qi, Qian; Wang, Xue-Qing; Chen, Xiao-Ming; Feng, Ying; Liu, Bo-Wen

    2016-06-01

    The Chinese white wax scale insect, Ericerus pela, can survive at extremely low temperatures, and some overwintering individuals exhibit supercooling at temperatures below -30°C. To investigate the deep supercooling ability of E. pela, transcriptomic and proteomic analyses were performed to delineate the major gene and protein families responsible for the deep supercooling ability of overwintering females. Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that genes involved in the mitogen-activated protein kinase, calcium, and PI3K-Akt signaling pathways and pathways associated with the biosynthesis of soluble sugars, sugar alcohols and free amino acids were dominant. Proteins responsible for low-temperature stress, such as cold acclimation proteins, glycerol biosynthesis-related enzymes and heat shock proteins (HSPs) were identified. However, no antifreeze proteins (AFPs) were identified through sequence similarity search methods. A random forest approach identified 388 putative AFPs in the proteome. The AFP gene ep-afp was expressed in Escherichia coli, and the expressed protein exhibited a thermal hysteresis activity of 0.97°C, suggesting its potential role in the deep supercooling ability of E. pela. PMID:26799455

  20. 胡萝卜与黄粉虫抗冻融合基因在拟南芥中的表达与抗冻性分析%Expression and Antifreeze Feature Analysis of the Daucus carota and Tentbrio molitor Fusion Antifreeze Protein Gene in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    张振华; 陈介南; 卢孟柱; 章怀云; 刘伯斌

    2012-01-01

    抗冻蛋白(antifreeze protein,AFP)是一类能控制冰晶生长和抑制冰晶之间发生重结晶的蛋白质,能在低温结冰条件下保护生物体不受伤害.抗冻蛋白具有2种明显不同的抗冻活性——热滞(thermal hysteresis,TH)活性和重结晶抑制(recrystallizationinhibition,RI)活性.鱼类和昆虫抗冻蛋白的特征是高TH低RI活性,而植物抗冻蛋白的特征是低TH高RI活性.为了获得高TH、高RI活性的抗冻蛋白(antifreeze protein,AFP),克隆得到胡萝卜抗冻蛋白基因(DcAFP)和黄粉虫抗冻蛋白基因(TmAFP)cDNA 全序列.通过重叠延伸PCR,将2个基因前后串联构建融合基因Dc- TmAFP和Tm -DcAFP,并构建了植物表达载体,通过农杆菌介导转化模式植物拟南芥,成功获得4个基因的转基因拟南芥植株.对转基因拟南芥植株进行抗冻试验处理,并进行了存活率统计和叶片黄化率统计分析.分析结果表明,不同功能的抗冻蛋白对植物的抗冻性有不同的帮助,热滞效应高效的黄粉虫抗冻蛋白对植物降低冰点方面效果大,而在植物遭受较长时间冻害时,抑制重结晶效应高效的胡萝卜抗冻蛋白对植物质外体中流体保持稳定性作用较大,从而提高植物的耐冻能力.%Antifreeze proteins (AFPs) are a family of proteins capable of protecting organisms from damage in freezing or sub-freezing conditions by controlling the growth of ice and inhibiting the recrystallization between ice granules, which are termed thermal hysteresis (TH) activity and recrystallization inhibition (RI) activity respectively. In comparison with the characteristic of high TH and low RI of fish AFPs and insect AFPs, antifreeze proteins of plants was low TH and high RI activity. In order to obtain antifreeze proteins with high TH and high RI activity, the complete cDNA of antifreeze protein genes (DcAFP and TmAFP) were cloned from Daucus carota and Tentbrio molitor. The two fusion antifreeze protein genes, Dc

  1. Crystal structure and mutational analysis of Ca2+-independent type II antifreeze protein from longsnout poacher, Brachyopsis rostratus.

    Science.gov (United States)

    Nishimiya, Yoshiyuki; Kondo, Hidemasa; Takamichi, Manabu; Sugimoto, Hiroshi; Suzuki, Mamoru; Miura, Ai; Tsuda, Sakae

    2008-10-10

    We recently found that longsnout poacher (Brachyosis rostratus) produces a Ca(2+)-independent type II antifreeze protein (lpAFP) and succeeded in expressing recombinant lpAFP using Phichia pastoris. Here, we report, for the first time, the X-ray crystal structure of lpAFP at 1.34 A resolution. The lpAFP structure displayed a relatively planar surface, which encompasses two loop regions (Cys86-Lys89 and Asn91-Cys97) and a short beta-strand (Trp109-Leu112) with three unstructured segments (Gly57-Ile58, Ala103-Ala104, and Pro113-His118). Electrostatic calculation of the protein surface showed that the relatively planar surface was divided roughly into a hydrophobic area (composed of the three unstructured segments lacking secondary structure) and a hydrophilic area (composed of the loops and beta-strand). Site-directed mutation of Ile58 with Phe at the center of the hydrophobic area decreased activity significantly, whereas mutation of Leu112 with Phe at an intermediate area between the hydrophobic and hydrophilic areas retained complete activity. In the hydrophilic area, a peptide-swap mutant in the loops retained 60% activity despite simultaneous mutations of eight residues. We conclude that the epicenter of the ice-binding site of lpAFP is the hydrophobic region, which is centered by Ile58, in the relatively planar surface. We built an ice-binding model for lpAFP on the basis of a lattice match of ice and constrained water oxygen atoms surrounding the hydrophobic area in the lpAFP structure. The model in which lpAFP has been docked to a secondary prism (2-1-10) plane, which is different from the one determined for Ca(2+)-independent type II AFP from sea raven (11-21), appears to explain the results of the mutagenesis analysis. PMID:18674542

  2. Anti-freezing Piping Design and Analysis of Chemical Plants in North China%我国北方地区化工装置管道防冻设计分析

    Institute of Scientific and Technical Information of China (English)

    王轲

    2016-01-01

    对于建设在北方地区的化工装置来说,冬季管道防冻一直是各生产企业非常重视的问题,但由于在设计阶段重视不够,往往给各化工生产企业的生产安全埋下了不小的隐患。本文从防冻设计源头控制的理念出发,优化管道布置,增加管道伴热,并从多方面、全角度阐述化工装置管道防冻设计要点,力求做到防患于未然。%In construction of a chemical plant in North China, pipeline anti-freezing has been the issue that production enterprises pay attentions to.Be-cause of insufficient attention to pipe anti-freezing at design stage, hidden troubles are existing for chemical production enterprises.In this paper, the au-thor starts from source control of anti-freezing design, optimizes piping layout, adds pipe tracing, and elaborates the anti-freezing piping design highlights of chemical plants from diversified aspects and angles, and strives to accomplish a nip in the bud.

  3. Heterologous expression of type I antifreeze peptide GS-5 in baker's yeast increases freeze tolerance and provides enhanced gas production in frozen dough.

    Science.gov (United States)

    Panadero, Joaquin; Randez-Gil, Francisca; Prieto, Jose Antonio

    2005-12-28

    The demand for frozen-dough products has increased notably in the baking industry. Nowadays, no appropriate industrial baker's yeast with optimal gassing capacity in frozen dough is, however, available, and it is unlikely that classical breeding programs could provide significant improvements of this trait. Antifreeze proteins, found in diverse organisms, display the ability to inhibit the growth of ice, allowing them to survive at temperatures below 0 degrees C. In this study a recombinant antifreeze peptide GS-5 was expressed from the polar fish grubby sculpin (Myoxocephalus aenaeus) in laboratory and industrial baker's yeast strains of Saccharomyces cerevisiae. Production of the recombinant protein increased freezing tolerance in both strains tested. Furthermore, expression of the GS-5 encoding gene enhanced notably the gassing rate and total gas production in frozen and frozen sweet doughs. These effects are unlikely to be due to reduced osmotic damage during freezing/thawing, because recombinant cells showed growth behavior similar to that of the parent under hypermosmotic stress conditions. PMID:16366681

  4. Antifreeze gene and its application in gene engineering%抗冻基因及其在基因工程中的应用研究进展

    Institute of Scientific and Technical Information of China (English)

    郝凤; 刘晓静; 周爱琴; 于铁峰

    2009-01-01

    低温是限制植物分布与生长的重要因素,低温伤害是一种严重的自然灾害,全球每年因此造成农作物的损失高达数千亿美元.本文综述了抗寒基因研究中一些已分离和鉴定出的低温诱导表达基因,对抗冻基因的功能特性和作用机制进行了全面的回顾,总结了抗冻基因工程的研究方向,对典型抗冻基因的表达效果进行了比较分析,并提出此领域尚存在的一些问题及发展前景.%Hypothermia is to limit the distribution and growth of plants important factor,Low-temperature injury is a serious natural disasters,The world′s crops each year resulting in the loss of up to hundreds of billions of dollars. Antifreeze genetic engineering is the field of biotechnology has been one of the hot research. Cold resistance gene has attracted wide attention from many countries scholars since it was been discovered. Many crops,especially fruits and vegetables,not only during cultivation in the fields,but also in post-harvest cold storage,frozen storage and frozen will be encountered during the processing of frozen injury. However, using conventional breeding methods to improve the cold tolerance of crops will encounter many difficulties. With the development of molecular biology,gene cloning technology involved in the progressive study of plant cold-hardiness,In this paper,resistance gene has been isolated and identified some of the low-temperature-induced gene expression,function and antifreeze mechanisms of cold resistance gene are reviewed,frost summed up the direction of genetic engineering research,on the typical effects of antifreeze genes in a comparative analysis of expression,and put forward in this field are still some problems and prospects.

  5. 防冻剂对自燃煤矸石混凝土力学性能影响研究%Study of Effects of Antifreezing Agents on Mechanical Properties of Spontaneous Combustion Coal Gangue Concrete

    Institute of Scientific and Technical Information of China (English)

    贾宝新; 李庆文; 梁鹏飞; 李桂秀

    2016-01-01

    为探究防冻剂对煤矸石混凝土力学性能的影响,以防冻剂种类、不同掺量和养护温度等为因素进行对比试验,分析其对煤矸石混凝土强度影响水平和作用机制。结果表明:通过单掺不同防冻剂标养煤矸石混凝土强度分析,早强效果显著性为氯化钙>硝酸钙>乙二醇;养护环境由负温度到正温度,基准煤矸石混凝土的抗压强度损失率与养护温度呈正相关;在-5℃和-10℃养护环境中,不同掺量3种防冻剂对负温煤矸石混凝土均起一定防冻效果,其显著性体现为氯化钙>硝酸钙>乙二醇。%In order to investigate thoroughly the effects of antifreezing agents on mechanical properties of coal gangue concrete, in consideration of various factors such as the kind of antifreezing agents, dosages of antifreezing agents and curing temperature, contrast test is conducted to analyze the inlfuence of these factors on coal gangue concrete strength and mechanism of action. The results show that the signiifcance of early strength, through mixing just one type of antifreezing agent each time, by analyzing compressive strength of coal gangue concrete under standard curing condition, is as follows: calcium chloride > calcium nitrate > ethylene glycol. The compressive strength loss rate of ifducial coal gangue concrete has positive correlation with curing temperature as curing environment varies from negative temperature to positive temperature. In addition, under different curing environment of -5℃ and -10℃, three types of antifreezing agents with different dosages exert antifreezing effect on negative temperature coal gangue concrete to some extent. The signiifcance of early strength is as follows: calcium chloride > calcium nitrate > ethylene glycol.

  6. Identification of antifreeze proteins and their functional residues by support vector machine and genetic algorithms based on n-peptide compositions.

    Directory of Open Access Journals (Sweden)

    Chin-Sheng Yu

    Full Text Available For the first time, multiple sets of n-peptide compositions from antifreeze protein (AFP sequences of various cold-adapted fish and insects were analyzed using support vector machine and genetic algorithms. The identification of AFPs is difficult because they exist as evolutionarily divergent types, and because their sequences and structures are present in limited numbers in currently available databases. Our results reveal that it is feasible to identify the shared sequential features among the various structural types of AFPs. Moreover, we were able to identify residues involved in ice binding without requiring knowledge of the three-dimensional structures of these AFPs. This approach should be useful for genomic and proteomic studies involving cold-adapted organisms.

  7. DSC Study on the Thermal Hysteresis Activity of Plant Antifreeze Proteins%沙冬青抗冻蛋白热滞活性的DSC研究

    Institute of Scientific and Technical Information of China (English)

    周晓蕾; 陈滔滔; 王保怀; 李芝芬; 费云标; 魏令波; 高素琴

    2001-01-01

    Differential scanning calorimetry (DSC) was used to measure thethermal hysteresis activity(THA) of plant antifreeze proteins(AFPs). The results reveal that DSC is a good method to screen and study AFPs. In the sixteen components extracted from Ammopipanthus mongolicus leaves, one(P3S1) was found to have apparent thermal hysteresis activity by DSC. As the amount of ice nuclei in the sample decreased, the THA of P3S1 increased from 0.01 ℃ to 0.65 ℃ . It is notable that the two-peak thermal hysteresis effect was observed. Two endothermic peaks appeared in the melting process of P3S1, while the freezing peak also consisted of two peaks. The peaks appeared antecedently showed larger thermal effect. This phenomenon shows P3S1 has two different kinds of interaction with water and ice crystal. It is probably an important property of a class of AFPs.

  8. Identification and Evaluation of Cryoprotective Peptides from Chicken Collagen: Ice-Growth Inhibition Activity Compared to That of Type I Antifreeze Proteins in Sucrose Model Systems.

    Science.gov (United States)

    Du, Lihui; Betti, Mirko

    2016-06-29

    The ability of chicken collagen peptides to inhibit the growth of ice crystals was evaluated and compared to that of fish antifreeze proteins (AFPs). This ice inhibition activity was assessed using a polarized microscope by measuring ice crystal dimensions in a sucrose model system with and without collagen peptides after seven thermal cycles. The system was stabilized at -25 °C and cycled between -16 and -12 °C. Five candidate peptides with ice inhibition activity were identified using liquid chromatography and tandem mass spectrometry and were then synthesized. Their ice inhibition capacity was compared to that of type I AFPs in a 23% sucrose model system. Specific collagen peptides with certain amino acid sequences reduced the extent of ice growth by approximately 70% at a relatively low concentration (1 mg/mL). These results suggest that specific collagen peptides may act in a noncolligative manner, inhibiting ice crystal growth like type I AFPs, but less efficiently. PMID:27293017

  9. Antifreeze effect and mechanism of sodium poly-γ-glutamate on backers' yeast cells%γ-聚谷氨酸钠对面包酵母的抗冻作用及其机理

    Institute of Scientific and Technical Information of China (English)

    时晓剑; 缪冶炼; 卫昊; 徐虹; 王冀宁

    2012-01-01

    γ-聚谷氨酸钠(γ—PGA钠)是由Y-聚谷氨酸与钠离子结合而成的水溶性物质,可以食用,无色无味。γ—PGA钠作为面包酵母抗冻剂,具有较强的实用性。在0.03~0.40℃/min的冷冻速率、-7~-60℃的冻藏温度条件下,探讨了γ—PGA钠对面包酵母的抗冻作用及其机理。实验结果表明,酵母细胞存活率在冻藏初期逐渐下降,6d后趋于稳定。γ—PGA钠对酵母的抗冻作用明显高于葡萄糖和谷氨酸。γ—PGA钠抑制了冷冻和冷藏过程中大冰晶的产生、以及冰晶的重结晶。在冷冻速率大于0.27℃/min、冻藏温度低于-30℃、冻藏时间6f1的条件下,添加1%的γ—PGA钠使酵母细胞存活率从无γ—PGA钠时的36.5%上升到67.5%。γ—PGA钠、葡萄糖和谷氨酸的抗冻活性分别为2.48、2.03和1.42。细胞存活率(η,%)随抗冻活性(Aa,-)的增加呈线性上升。γ—PGA钠具有较大抗冻活性的机理是,γ—PGA钠的解离度较大,并且Na+能够固定较多的水分子。%Sodium poly-γ-glutamate (Na-γ-PGA), a water-soluble polyamide composed of poly-γ- glutamic acid and sodium ion, is edible, tasteless, colorless and odorless. It is considered as a potential cryoprotectant for backers' yeast. In the present study, the antifreeze effect of Na-γ-PGA on bakers' yeast cells was investigated in the freezing rate range of 0.03-0.40 ℃/min and the storage temperature range of -7--60 ℃. The mechanism of the antifreeze effect was also discussed. The experimental results showed that the survival ratio of yeast cells decreased at the beginning, and was constant after 6 dduring frozen storage. Na-γ-PGA had greater antifreeze effect on the yeast cells than glutamic acid and glucose. It inhibited both the generation of big-size ice crystals during freezing and the recrystallization of ice crystals during freezing storage. Under the condition of a freezing rate at 0

  10. Preparation of Food-based Antifreeze Peptides and Research on the Ice Crystal Inhibition%食品源抗冻多肽的制备及冰晶抑制作用研究

    Institute of Scientific and Technical Information of China (English)

    洪晶; 汪少芸; 吴金鸿; 饶平凡

    2013-01-01

    Objective:Antifreeze protein is becoming a popular research point because it could inhibit ice crystal growth, reduce damage of cell membranes and maintain products' quality during food during storage and handling. Methods:This paper reports that gelatin peptides of a certain molecular size range with compact-packed structural domain derived from Papain hydrolysis of bovine gelatin are able to inhibit recrystallization of ice crystals in ice cream mix and show natural antifreeze activity. Results:The optimum conditions for producing antifreeze peptides were hydrolysis at pH 7.0 for 30 min at 37℃ and an Papain to gelatin ratio of 1 :10. The gelatin peptides were fractionated on size exclusion (Sephadex C-SO) and ion exchange (sulfopropyl-Sephadex C-2S) columns, and the molecular mass distribution of the antifreeze peptide fractions was determined by matrixassisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry. The gelatin peptide fractions in the molecular mass range of 700~1 318 u strongly inhibited ice recrystallization in ice cream mix. Conclusion:The highly effective antifreeze peptide on ice crystal inhibition shows specific rules during cold-heat-stage cycles, the key approach is how to control hydrolysis conditions. It probably exists the surface hydropholic-complementary interaction between antifreeze peptide and ice molecules.%目的:因抗冻蛋白具有控制冰晶生长,减少细胞损伤及保持产品原有组织结构、质地和品质的特点和突出意义而成为研究的热点.方法:以食品源的食用明胶为原材料,通过控制木瓜蛋白酶的切割条件,将活性多肤切割为具有特定的肽链长度和结构组成,从而使抗冻活性得以高效实现.结果:酶切多肽抗冻活性的实现受酶/底物比、酶解时间、酶解温度等条件的影响.优化的酶解条件为:pH 7.0,酶/底物配比1:10;酶解时间30 min;酶解温度37℃.通过Sephadex G-50和Sephadex C-25色谱分离

  11. Improvement and application of sodium sulfite type concrete antifreeze%亚钠型混凝土防冻剂的改进与应用

    Institute of Scientific and Technical Information of China (English)

    付饶

    2015-01-01

    In order to solve the cold freezing problems of early age concrete at the cold season in the northeast , northwest an north of Chi-na, a small amount of vitamin C,vitamin D,fluorocarbon surfactantFN -3 were introduced in the sodium type concrete antifreeze and ap-plied to the winter construction of concrete .The fluidity loss is less than 30% within 2 hours.The capillary channel and the pervious of concrete significantly reduced .While the anti permeability and anti freeze properties improved obviously .This research reached the goal of improving the strength of concrete ,promoting and optimizing the formation of early age concrete slurry structure and reinforcing later strength of the concrete .%为解决在东北、华北、西北地区寒冷季节早期混凝土的冻害问题,在通用的亚钠型混凝土防冻剂中引入少量的维生素C、维生素D、氟碳表面活性剂FN-3,加入到冬季施工的混凝土中,2h的流动度损失小于30%,混凝土的毛细通道显著减少,降低了混凝土的透水性,其抗渗和防冻性能明显提高。达到提高混凝土早期防冻能力,促进、优化早期混凝土浆体结构的形成,增大混凝土后期强度的目的。

  12. Anti-freezing System's Status and Improvement of Sluice Gate in Huangbizhuang Reservoir%黄壁庄水库闸门防冻系统的状况及改进

    Institute of Scientific and Technical Information of China (English)

    郭文宇

    2013-01-01

    Itcombinedwiththeoperationpracticecomparedthreekindsofanti-freezingmeasures(diggingiceditch,anti-freezingsystemofsub-mersible pump, and anti-freezing system of air compressor) of the sluice gate in winter. It puts forward the improvement measures and practica-bility of anti-freezing system of submersible pump in Huangbizhuang reservoir, and puts forward some ideas for the further improvement.%结合黄壁庄水库冬季闸门运行实践,对闸门的三种防冰冻措施(开凿冰沟、潜水泵防冰冻系统、压缩空气泡防冰冻系统)进行了比较。结合潜水泵式防冰冻系统在黄壁庄水库的应用实践,提出了此系统对于北方水库的实用性改进措施,并根据实际应用中积累的经验提出了进一步的改进设想。

  13. Research on high temperature stability of including salt anti-freezing asphalt mixture%蓄盐类抑制冻结沥青混合料高温性能研究

    Institute of Scientific and Technical Information of China (English)

    钟科

    2014-01-01

    In order to evaluate the high temperature performance of including salt anti-freezing asphalt mixture,ordinary asphalt mixture,anti-freezing asphalt mixture and anti-freezing asphalt mixture with rubber particles were chosen to carry out high temperature rutting test and immer-sion rutting test. The results show that whether there is the role of water or not,anti-freezing asphalt mixture with rubber particles shows more ex-cellent high temperature performance,compared with other two asphalt mixture.%为了研究蓄盐类抑制冻结沥青混合料的高温抗车辙性能,选取普通沥青混合料、抑制冻结沥青混合料及掺橡胶颗粒的抑制冻结沥青混合料,分别进行干法车辙试验和浸水车辙试验,结果表明:无论干法车辙或是浸水车辙,掺橡胶颗粒的抑制冻结沥青混合料都拥有良好的高温性能,优于其他两种沥青混合料。

  14. 干混抗冻混凝土配合比设计及抗冻性能研究%Dry-mixed antifreeze concretes design of mixing proportion and performance of winter

    Institute of Scientific and Technical Information of China (English)

    罗憨; 李延和; 夏永清; 范贤玉

    2014-01-01

    随着建筑市场的飞速发展,混凝土冬季施工在所难免。且我国北方地区气候寒冷,普通商品混凝土不能满足建筑工程要求。介绍一种特殊的混凝土---干混抗冻混凝土,通过模拟冬季施工环境,调整混凝土配合比,在满足混凝土强度要求前提下,找出最适宜的干混抗冻混凝土配合比。%With the rapid development of the construction market,concrete construction in winter is inevitable.Since the weather is cold,ordinary concrete construction can not meet the requirements.This paper describes a special concrete-dry-mixed concrete antifreeze. By simulating winter construction environment,adjust the concrete mix,concrete strength to meet the requirements of the premise,we want to identify the most suitable dry-mixed antifreeze concrete mix.

  15. Influence of frozen dough processing conditions on the activity of antifreeze yeast in fermented dough%冷冻工艺条件对发酵面团中抗冻酵母活性的影响

    Institute of Scientific and Technical Information of China (English)

    周璐; 孙冰玉; 石彦国; 梁金钟

    2011-01-01

    研究了冷冻面团的冷冻终结温度、冻藏温度、冻藏时间对抗冻酵母活性的影响,得出最有利于抗冻酵母活性保持的冷冻工艺条件:冷冻终结温度-18℃,冻藏温度应与冷冻终结温度保持一致,贮存时间不超过30d为宜。%The effects of the end of freezing temperature,freeze preservation temperature and freeze preservation time of frozen dough on the activity of antifreeze yeast were researched.The most beneficial freezing process conditions to keep the activity of antifreeze yeast were found.The end of freezing temperature was-18℃,freeze preservation temperature should be consistent with the end of the freezing temperature.And it's better to keep the freeze preservation time less than 30 days.

  16. 印楝Azadirachta Indica A.Juss的冷驯化与抗冻蛋白的研究%On Cold-Acclimation and Antifreeze Proteins of Azadirachta Indica A.Juss

    Institute of Scientific and Technical Information of China (English)

    王颖; 杨光伟

    2012-01-01

    The micropropagation system has been established through plant tissue culture technology with traditional herbal plant Azadirachta Indica A. Juss as material before cold acclimation process is carried out; in vivo antifreeze proteins of neem have been investigated and analyzed. The main results are as follows: ①After cold acclimation, total amount of neem protein increases and several new proteins produce. However, with the cold treatment for too long a time, amount of the neem cold-induced proteins decrease, and even some of them are degradated. ②The stability of antifreeze proteinfrom neem is related to the time of cold treatment in cold acclimation. The shortest time for antifreeze protein production is two weeks in 5℃ , and the cold resistant limit of neem is in 5℃ for 20 days. When the temperature drops below 0℃ , AFPs are accumulated in the first days of cold treatment(0~ 15 d). However, while the treatment time i.s prolonged, Antifreeze protein are degradated and dismissed on the 30th day. ③ Purified antifreeze protein is obtained, and the relative molecular mass is around 36 KD.%采用木本植物材料——印楝,通过组织培养建立快繁体系,然后对其进行冷驯化处理,并分析检测印楝植物体内抗冻蛋白.主要结果如下:①冷驯化处理后印楝的总蛋白一些表现为量的增加同时会有新的蛋白产生.但脱驯化或处理时间过长时,抗冻蛋白在量的表达上会有逐渐减少或消失的现象.②在对印楝的冷驯化中,发现不同的温度处理后蛋白稳定存在的时间不同.抗冻蛋白出现的最早时期为5℃处理2周左右,印楝能耐受的稳定最低温为5℃,所持续的最长时间约为20 d.在0℃低温处理后,虽然在处理初期(0~15 d)也有抗冻蛋白的产生,但随处理时间的延长,这种差异逐渐减少,在处理30 d时完全消失.③得到了分离纯化的抗冻蛋白,其相对分子质量约为3.6×104.

  17. 防冻剂对混凝土引气剂气泡稳定性能影响研究∗%Impact study of anti-freezing agent on bubble stability performance of concrete air-entraining agent

    Institute of Scientific and Technical Information of China (English)

    张向东; 李庆文; 李广华; 李桂秀

    2015-01-01

    为探究防冻剂对混凝土引气剂气泡稳定性能的影响,考虑4种防冻剂及不同掺量等敏感性因素进行水泥稀浆摇泡实验,分析其对引气剂起泡与稳泡能力影响及作用机理。结果表明,建立摇泡实验的气泡体积衰减指数模型,其参数能表征不同引气剂起泡与稳泡能力;硝酸钙对皂苷类引气剂稳泡能力有正作用,防冻剂对其起泡能力均有负作用;乙二醇对苯磺酸盐类引气剂起泡能力有正作用,对其稳泡能力有正作用,表现为亚硝酸钙>硝酸钙>乙二醇;4种防冻剂对掺皂苷类引气剂的新拌混凝土含气量均有负影响,其显著性为乙二醇最强,亚硝酸钙最弱,钙盐类防冻剂对掺苯磺酸盐类引气剂均有负作用,乙二醇对其有正作用。%In order to explore the influence of anti-freezing agent on bubble stability performance of concrete air-entraining agent,the cement slurry bubble test was carried out considering sensitivity factors which was four kinds of anti-freezing agents and different dosages,and analyzed its effects on foaming ability,stabilizing foam ability and mechanism.The results revealed that bubble volume attenuation index model of shake bubble test was set up,which parameters characterized the foaming ability and stabilizing foam ability of different air-en-training agents.Calcium nitrate had a positive effect on stabilizing foam ability of the saponins air-entraining agent,and anti-freezing agents had a negative effect on it.Ethylene glycol had a positive effect on foaming abili-ty of the benzene sulfonate air-entraining agent,the significance of improving the stabilizing foam ability was calcium nitrite>calcium nitrate>ethylene glycol.Four kinds of anti-freezing agents all had a negative impact on the air content of fresh concrete mixed with the saponins air-entraining agent,the most significant of it was ethylene glycol,and the least significant was calcium nitrite

  18. 抗冻蛋白应用前景及基因工程表达研究进展%Researches Advances in Application of Antifreeze Protein and Its Gene Engineering Expression

    Institute of Scientific and Technical Information of China (English)

    蔡文萍; 马纪

    2012-01-01

    抗冻蛋白(antifreeze protein,AFP)又称为热滞蛋白,是一类抑制冰晶生长的蛋白,它具有三个基本特征:热滞效应(thermal hysteresis activity,THA)、冰晶形态效应和重结晶抑制效应(frecrystallization inhibition,RI),抗冻蛋白是一类广泛存在于鱼类、植物、真菌、昆虫中的蛋白,不同生物的AFPs的化学结构、理化性质、空间构型各不相同,并且同类生物之间的AFPs同源性也不高,不存在相似性序列或结构模式,说明它们可能是在不同的有机体中独立进化而来,没有共同的演化规律.随着研究的深入,抗冻蛋白可广泛应用于医学农学食品工业等领域,起到冷冻保护剂,食品添加剂的作用,前人已经对抗冻蛋白的结构、生化性质和抗冻机制进行了阐述,研究主要对抗冻蛋白应用方面及基因工程的表达作了系统综述,为抗冻蛋白的深入研究奠定基础.%Antifreeze protein (AFP) , also known as thermal hysteresis protein, It is a class of proteinThat inhibiting the growth of ice crystals. It has three basic characteristics; thermal hysteresis effect (THA), the effect of ice crystals form, recrystallization inhibitory effect (RI), To date, AFPs have been widely found in a variety of organisms, such as fish, insects, plants, bacteria and fungi, isolated from a number of fish, plants , bacteria, fungi and arthropods . Different biological AFPs chemical structure, physical and chemical properties, spatial configuration of each are not identical, and similar biological between AFPs homology is not high, there is no similar sequence or structural patterns, indicating that they may be in different organisms evolved independently, there is no common evolution law. Along with the development of research, Antifreeze protein can be widely used in agriculture, medicine food sciences and industry, It played a role in the cryoprotectant and food additives. The biochemical characteristics, as well as antifreeze

  19. Study on the Anti-freezing Technology to Mountain Tea Plantations%山地茶园防冻技术研究

    Institute of Scientific and Technical Information of China (English)

    王烨军; 黄建琴; 罗仲兴; 张必桦; 徐奕鼎

    2009-01-01

    Six kinds of technical measures (pruning, covering couch grass, mulching plastic film, sprinkling irri-gation antifreeze etc.) were used to mountain tea plantations to improve the capacity of frost resistance and study the relationship between the enzyme activity of SOD, POD and freezing rates. The results showed that: (1) with freezing rates increase, the enzyme activity of SOD also increases accordingly, in a certain range to various technical measures. This is because tea plants have the self-repairing ability; (2) to mountain tea plantations; the technical measures used directly to crown of tea plant have better effect than used to environment and soil because of wind-chill effect. The result of six kinds of the technical measures is: mulching plastic film > cover-ing couch grass > CK> no pruning>irrigating roots> spraying crown; (3) It's beneficial to tea plant to reduce freezing injury with suitable pruning in autumn.%研究了修剪、铺草、覆膜、喷灌防冻剂等6项技术措施对山地茶园茶树的抗寒性影响及SOD、POD酶活性与受冻率之间的关系,结果表明:①各处理随着受冻率的增加,在一定范围内SOD酶活性也相应增加,这与茶树自身的修复功能有关;②对于山地茶园,受风冻影响,直接应用于茶树树冠的技术措施要比应用于环境及土壤的技术措施效果好.6种处理效果为:覆膜>铺草>对照>未修剪>灌根>喷冠;③秋天进行适当的修剪,对降低茶树冻害有利.

  20. 白菜型冬油菜质外体抗冻蛋白研究%Study on apoplast anti-freeze proteins in winter turnip rape (Brassica rape L.)

    Institute of Scientific and Technical Information of China (English)

    杨刚; 刘林波; 杨建胜; 方园; 张娟; 史鹏辉; 孙万仓; 刘自刚; 曾秀存; 武军艳; 方彦; 李学才; 陈奇

    2016-01-01

    The objective of this paper was to lay the basis for studying cold resistance of winter rapeseed. The anti-freeze activities of apoplast proteins were determined in the ‘Longyou 6’ winter rape leaves and roots under cold vernalization. The apoplast proteins were separated by SDS-PAGE and high expression proteins identified in MALDI-TOF/TOF mass spectrometry under field and pot experiments. The results showed that apoplast protein content of ‘Longyou 6’ leaves increased significantly (P < 0.05) after cold acclimation in an artificial climate chamber, reaching 92.31 µg•g-1(FW) on the fifth day, which represented an increase of 246.12% over CK. Apoplast protein content after 10-15 days of cold acclimation dropped compared with that after 5 days, but was still significantly higher than that of CK (P < 0.05). Apoplast protein content continued to increase with increasing cold acclimation time from 20 to 25 days (P < 0.05). Apoplast protein content decreased significantly with after 10 days of de-acclimation. In the process of cold acclimation, apoplast protein content of ‘Longyou 6’ leaves significantly accumulated. However, it decreased significantly after de-acclimation. Obviously, apoplast proteins of‘Longyou 6’ winter rape belonged to low temperature induced proteins. Anti-freeze activity detection analysis suggested that apoplast proteins had re-crystallization inhibition activity. Mass spectrometry identification revealed a variety of proteins with unclear functions along with β-1-3-glucanase consistent anti-freeze proteins reported in winter rye. The class glucanase detected by mass spectrometry was found to have weaker ice crystal forms due to modification effect with reclamation and anti-freeze activity test. The test suggested that this class glucanase was a low activity anti-freeze protein. Many anti-freeze proteins were synthesized and secreted by winter rape in apoplast of leaves and roots under low temperature stress. The proteins

  1. 素混凝土抗冻性能试验研究%Experimental investigation on anti-freeze behavior of plain concrete

    Institute of Scientific and Technical Information of China (English)

    方从启; 张俊萌; 段桂珍

    2014-01-01

    In order to further study the antifreeze performance difference of confined concrete and plain concrete,in confined concrete model for reference,making the same ratio of plain concrete cubic block and under the same conditions were also tested under freeze-thaw cycle of different numbers as 0,20,40,60,100 and 120 times,As the second part,mainly analyzed the compressive strength of plain concrete under freeze-thaw test,mass loss of samples and water absorption performance changing with the number of freezing and thawing,and establish the freeze-thaw damage prediction model of concrete compressive strength and mass loss ratio.Experiment showed that with the increase of freeze-thaw cycles,the compressive strength of plain concrete decreased parabola,drying quality and full water mass linearly decreased,while water absorption decreased by double line.From the aspects of material level,fly ash had a greater influence on the loss of concrete compressive strength,mass loss rate and water absorption,while water cement ratio had little influence on the above indicators.The loss of compressive strength of mixing 15%fly ash concrete was about 20%to 30%higher than mixing no fly ash concrete;Mass loss rate was about 5%to 6%larger than not mixing fly ash ,fly ash is not conducive to the antifreeze performance of concrete.As the same fly ash,the loss of compressive strength,mass and bibulous rate in low water-cement ratio concrete changed lager than high water cement ratio.When using fly ash concrete,it is easy to reduce the water cement ratio.%为了进一步研究约束混凝土和无约束混凝土的抗冻性能差异,以约束混凝土模型为参照,制作相同配合比的素混凝土立方体块并在相同条件下进行0、20、40、60、100、120次的冻融腐蚀试验。主要分析冻融腐蚀下素混凝土试块抗压强度,质量损失以及吸水率等性能随冻融次数的变化规律,并建立素混凝土抗压强度和质量损失冻融损伤预测

  2. The Roles of Insects Body Cold-resistance Effects on Ice Nucleation Proteins and Insect Antifreeze Proteins%冰核蛋白和昆虫抗冻蛋白在虫体抗寒中的作用

    Institute of Scientific and Technical Information of China (English)

    周世豪; 袁哲明

    2012-01-01

    为了冰核蛋白和昆虫抗冻蛋白共同维持虫体在寒冬中的动态平衡.尝试着从冰核蛋白和昆虫抗冻蛋白的结构和功能出发,阐述两者在虫体中的抗寒作用,有助于日后更为深入的研究.%In order to the ice nucleation proteins (INPs) and the insects antifreeze proteins (AFPs) are two closely related to the body of insects, intervening of antagonism and synergy have maintained the dynamical equilibrium in the body of insects in winter. This paper expounds on two of the body in insect role, further cold more in-depth research.

  3. Research on the structure of antifreeze asphalt pavement made from rubber particles%橡胶颗粒防冻性沥青路面结构组合研究

    Institute of Scientific and Technical Information of China (English)

    郭平; 吴德军; 田伟平; 刘雨迪; 张岁应

    2011-01-01

    为研究橡胶颗粒沥青混合料作为沥青路面不同层位与ATB、AC结构组合下沥青路面的防冻性能的变化规律,通过ANSYS有限元软件模拟冰层的受力过程,分析不同路面结构组合下的荷载响应效果.结果表明:橡胶颗粒沥青混合料作为上面层时具有较好的防冻性能;作为中面层时可明显提高路面抗车辙性能,但破冰性能降低.最后,建议采用ATB作下面层与橡胶颗粒沥青混合料作中、上面层搭配的组合结构可有效改善沥青面层的永久变形及破冰性能.%In order to study the variation of anti-freezing capability of the asphalt pavement which is made from the mixture of asphalt and rubber particles and composed of different layers and ATB/AC structure, responses of the pavement to loads were analyzed by simulating the stressed process of the ice layer with ANSYS. The results indicate that when the asphalt mixed with rubber particles was used as the surface layer, the anti-freezing capability of the pavement was enhenced. When the mixture was used as the middle layer, the anti-rutting performance could be improved significantly but the ice-breaking performance was reduced. Finally, the combination of ATB as the bottom layer and the asphalt mixture of rubber particles as the middle and surface layer is advised to be adopted,which can improve effectively the permanent deformation and ice-breaking performance.

  4. 天津机场第二跑道工程道面混凝土抗冻性能研究%Research on Concrete Anti-freezing Performance of the Second Runway of Tianjin Airport

    Institute of Scientific and Technical Information of China (English)

    高志斌; 刘岩

    2011-01-01

    以天津机场第二跑道工程为背景,从配制参数、材料、试验条件等角度出发,开展机场道面混凝土抗冻性能影响因素的研究.基于此,运用混凝土损伤力学理论与材料疲劳理论,将损伤力学的损伤度概念应用于混凝土冻融疲劳破坏损伤中,结合天津机场道面混凝土多年的现场工程试验数据,建立了机场道面混凝土抗冻耐久性的数学预测模型,并将其应用到道面混凝土冬季施工配合比设计中,从而降低道面的耐久性劣化风险,提高机场道面结构安全性,保障跑道使用寿命和飞机飞行安全.%Based on construction of the second runway of Tianjin Airport, the research is carried out about the influence factors of the concrete anti-freezing performance of the airport pavement from the aspect of mix parameters, material and test condition. With the theory of damage mechanics and fatigue of materials, the damage degree of damage mechanics is applied to analyze fatigue damage of freezing-thawing of concrete. With several years of engineering test data of Tianjin Airport, a math-predicting model of the anti-freezing performance of the concrete of airport pavement is built and used in the design of concrete mix proportion of airport pavement for winter construction in order to reduce the durability degradation of concrete pavement, and improve the safety of the airport pavement structure and ensure the service life of the airport runway and the safety of aircraft flight.

  5. Mix Study of C 50 Antifreeze Concrete of North Water Transfer Project%南水北调中线工程C50抗冻混凝土配合比试验研究

    Institute of Scientific and Technical Information of China (English)

    王利娟; 焦建国

    2011-01-01

    南水北调中线一期工程总干渠Ⅳ渠服役环境较为恶劣,混凝土冻融破坏问题突出.立足工程区域的地材特点,开展了原材料性能指标测试、混凝土试配以及抗冻性能检测等试验研究工作,配制出工作性能优异、耐久性能好的C 50F 200混凝土,并提出了相应的施工质量控制措施.%The service environment of main channel of midline first phase of North Water Transfer Project is serious, Freeze-thaw damage problem of concrete is prominent. Based on the material characters of local work site area, the performance index test of raw materials, concrete mix test and concrete antifreeze test are carried out. Through these test works, C 50 F 200 concrete with excellent work performance is obtained, and the corresponding measures of construction quality control are suggested.

  6. Structure and collective dynamics of hydrated anti-freeze protein type III from 180 K to 298 K by X-ray diffraction and inelastic X-ray scattering

    Science.gov (United States)

    Yoshida, Koji; Baron, Alfred Q. R.; Uchiyama, Hiroshi; Tsutsui, Satoshi; Yamaguchi, Toshio

    2016-04-01

    We investigated hydrated antifreeze protein type III (AFP III) powder with a hydration level h (=mass of water/mass of protein) of 0.4 in the temperature range between 180 K and 298 K using X-ray diffraction and inelastic X-ray scattering (IXS). The X-ray diffraction data showed smooth, largely monotonic changes between 180 K and 298 K without freezing water. Meanwhile, the collective dynamics observed by IXS showed a strong change in the sound velocity at 180 K, after being largely temperature independent at higher temperatures (298-220 K). We interpret this change in terms of the dynamic transition previously discussed using other probes including THz IR absorption spectroscopy and incoherent elastic and quasi-elastic neutron scattering. This finding suggests that the dynamic transition of hydrated proteins is observable on the subpicosecond time scale as well as nano- and pico-second scales, both in collective dynamics from IXS and single particle dynamics from neutron scattering. Moreover, it is most likely that the dynamic transition of hydrated AFP III is not directly correlated with its hydration structure.

  7. Preparation and application of antifreeze proteins extracted from winter wheat bran%冬小麦抗冻蛋白制备及其在汤圆中的应用研究

    Institute of Scientific and Technical Information of China (English)

    夏露; 张超; 王立; 张晖

    2009-01-01

    研究了冬小麦麸皮抗冻蛋白的制备方法及其在速冻汤圆中的应用.研究确定冬小麦麸皮抗冻蛋白的提取工艺为:pH8.0,提取时间3h,液料比5:1,该条件下小麦麸皮水溶性蛋白质提取率达到38%,其中含抗冻蛋白1.6%.抗冻蛋白粗品在汤圆中的应用实验结果显示,2.5%的蛋白添加量对汤圆的品质有明显的改善效果.%The preparation and application of antifreeze proteins (AFPs) were studied.The extraction process of AFPs from winter wheat bran was optimized as following, water/material ratio 5:1, pH 8.0, extraction time 3h.The extraction rate of soluble protein from winter wheat bran was 38%, and the AFPs content in the extraction (crude AFPs) was 1.6%.The application experiment of AFP in rice dumpling showed that the quality of rice dumpling would be improved by adding with 2.5% crude AFPs.

  8. Cloning and sequencing of antifreeze protein gene inDaucus carota var \\%sativus\\% Hoffm Deutschl%胡萝卜var sativus Hoffm Deutschl抗冻蛋白基因的克隆及测序

    Institute of Scientific and Technical Information of China (English)

    尹明安; 崔鸿文; 樊代明; 郭立

    2001-01-01

    Antifreeze protein gene (afp) in three native carrot cultivars(Daucus carota var \\%sativus\\% Hoffm Deutschl),Wuzhong carrot in Ningxia,H uaxian carrot in Shaanxi and Hanzhong carrot in Shaanxi,was cloned by PCR (polym erase chain reaction).Wuzhong carrots afp was sequenced and its sequence w as compared with that of Daucus carota var \\%autumn\\% King from British.Ther e were 35 different bases between two varieties in 1004 sequenced nucleotides,among which there were 20 nonsense mutations and 15 sense mutations.Based on sense mutations homology was 98.5%.%以宁夏吴忠胡萝卜、陕西华县胡萝卜、陕西汉中胡萝卜3个地方品种为材料,用PCR方法克隆了中国胡萝卜var\\%sativus\\%HoffmDeutschl的抗冻蛋白基因\\%afp\\%,测定了宁夏吴忠胡萝卜\\%afp\\%的核苷酸序列,和英国胡萝卜var\\%autumn\\%King\\%afp\\%序列对比,在所测1004个核苷酸中,有35个碱基不同,其中无义突变20个,有义突变15个。按有义突变计,同源性为\\{98.5%\\}

  9. Experimental Analysis on Mix Proportion Design and Mechanical Properties of Anti-freezing and Anti-permeability Concrete with Low Strength%低强度抗冻抗渗混凝土配合比设计及力学特性试验分析

    Institute of Scientific and Technical Information of China (English)

    黄丽彬

    2015-01-01

    In this paper, the mix proportion of low strength concrete was designed by the scien-tific method, and its performance of anti-freezing and anti-permeability were studied, and the effect of the air entrainment agent dosage and the optimal water cement ratio on the anti-freezing performance, the anti-permeability performance and the strength of concrete were synchronously analyzed. Through deep research we can find out that in cold environment, the requirements of the anti-permeability performance and the strength of concrete should be meet in the construc-tion project, by using of low strength concrete, as long as adding moderate amount of air en-trained agent and maintaining appropriate water cement ratio, the persistent anti-freezing per-formance of the low strength concrete could be enhanced.%通过科学设计低强度混凝土的配合比,研究分析其抗冻、抗渗功能,并同步分析引气剂掺量、最优水灰比例对混凝土抗冻性、抗渗性及强度的作用。通过深入研究发现,严寒环境下符合建筑项目混凝土抗渗、强度的要求,采用低强度混凝土,只要掺入适量的引气剂、保持合适的水灰比例,就能增强低强度混凝土的持久的抗冻性能。

  10. 脊尾白虾虾糜的制备及其抗冷冻变性工艺%Technology of shrimp surimi preparation from Exopalaemon carinicauda and its anti-freeze denaturation

    Institute of Scientific and Technical Information of China (English)

    曹文红; 赵子科; 田申; 陈良

    2015-01-01

    This paper studied the rinsing technology and anti-freeze denaturation technology of shrimp surimi made from Exopalaemon carinicauda.The effect of different rinsing conditions on gel strength and elasticity of the minced shrimp were determined and estimated.With the weighted value of the gel strength and elasticity as the indexes,the rinsing process technology was optimized with an orthogonal trial.The optimal conditions were:rinsing time 7 min,shrimp meat:water ratio 1∶9,CaCl2 concentration 0.7%.In order to understand the influence of frozen storage on the quality of the rinsed shrimp meat,trehalose,sodium lactate,sorbitol and sucrose were used as cryoprotectants,salt-soluble protein content,Ca2+-ATPase activity,total sulfhydryl content,gel strength and pH of the rinsed shrimp meat were determined and compared during a storage of 8 weeks.The results indicated that all cryoprotectants showed good anti-freeze denaturation activity on rinsed shrimp meat as compared to the control samples.The trehalose added samples had better anti-frozen effect than other cryoprotectants added samples.The results of this research show that shrimp surimi of Exopalaemon carinicauda can remain better qualities after a relatively long time storage.%以脊尾白虾为原料,研究虾糜漂洗工艺及其抗冷冻变性工艺.以凝胶强度和弹性为指标,探索不同漂洗条件对虾糜凝胶性能的影响,以凝胶强度和弹性的加权平均值为指标进行正交试验得出虾糜最佳的漂洗工艺为:漂洗时间7 min,料水比1∶9(g∶ mL),漂洗液CaCl2浓度0.7%.为研究冻藏对虾糜品质的影响,以海藻糖、乳酸钠、山梨糖醇、蔗糖等为抗冻剂,比较了添加不同抗冻剂时8周冻藏期间内虾糜的盐溶蛋白含量、Ca2-AT-Pase、总巯基含量、凝胶强度、pH值的变化规律.结果显示:不同抗冻剂均能较好地抑制脊尾白虾虾糜蛋白质的冷冻变性,海藻糖的抗冻效果优于另外两种抗冻剂.研究表

  11. 冰亲和吸附装置对胶原抗冻肽的分离纯化%Purification of antifreeze collagen peptides by ice affinity adsorption protocol

    Institute of Scientific and Technical Information of China (English)

    阮功成; 曹慧; 徐斐; 于劲松

    2015-01-01

    抗冻肽是一类可以非依数性降低体系冰点的多肽,在生命体内具有非常重要的生理作用.研究搭建了冰亲和吸附装置,并以微生物保护活性为指标,优化了其对猪皮胶原酶解复合物中胶原抗冻肽的吸附条件,同时对分离产物的性质进行了研究.结果表明:在胶原酶解复合物浓度为1 mg/mL,吸附时间为10h,吸附温度为-5℃,吸附次数为2次的条件下,所获得的胶原抗冻肽对微生物的低温保护活性最强.经过冰亲和吸附后,胶原抗冻肽的主要洗脱峰之间的分离效果明显增加,其胶原抗冻肽的分子质量主要分布小于1 000 Da、且富含甘氨酸、脯氨酸和羟脯氨酸.%Antifreeze collagen peptides is a family of peptides which can lowering the freezing point of the system non-colligatively.This plays an important role in protecting organisms from freezing injury and damage.In this study, we studied the ice affinity adsorption equipment, used micro-organisms protection as the index to optimize the condition of purifying pig skin collagen peptides by enzymatic hydrolysis.The optimum conditions were: crude mixture concentration of 1 mg/mL, at-5 ℃ for 10 hour, adsorption twice.After ice affinity adsorption, collagen peptides peaks had better separation effect, the molecular weight mainly distributed within the range of 1000 Da, and major collagen amino acids were Proline and Hydroxyproline.

  12. Patrones electroforéticos de proteínas y actividad anticongelante en el apoplasto de la hoja de la especie andina tropical Senecio niveoaureus PROTEIN ELECTROPHORETIC PATTERNS AND ANTIFREEZING ACTIVITY IN THE LEAF APOPLAST OF THE TROPICAL ANDEAN SPECIES Senecio niveoaureus

    Directory of Open Access Journals (Sweden)

    F ÁLVAREZFLÓREZ

    2006-06-01

    Full Text Available Las plantas de alta montaña tienen diferentes adaptaciones para sobrevivir a cambios drásticos de temperatura, especialmente a condiciones de congelamiento. En plantas de invierno, la supervivencia a temperaturas bajas está relacionada con la capacidad de las células para producir proteínas específicas de bajo peso molecular (proteínas anticongelantes y exportarlas al apoplasto. Para establecer si plantas tropicales de alta montaña sobreviven las temperaturas bajas a través del mismo mecanismo, se colectaron hojas de plantas de Senecio niveoaureus durante 24 horas y a dos alturas 3.300 y 3.600 msnm en el Páramo de Palacio, Chingaza, Colombia. Se observaron proteínas apoplásticas de pesos moleculares entre 3512 kDa. Los patrones electroforéticos fueron diferentes dependiendo de la altura y la hora de muestreo, sin embargo, se observaron variaciones en el patrón de bandeo que no pueden ser atribuidas ni a la temperatura ni al gradiente altitudinal únicamente. Se detectó actividad anticongelante en el apoplasto de hojas de S. niveoaureus, siendo este el primer reporte en especies tropicales de alta montaña.Tropical high mountain plants have different adaptations to survive extreme daily temperature fluctuations and specially freezing night conditions. In winter plant species, survival to low temperatures is related to the ability of the cell to produce specific low molecular weight proteins (antifreezing proteins and to export them to the apoplast. In order to see if high mountain tropical plants survive to low temperatures through the same mechanism we collected, during a 24 hourperiod, leaves from Senecio niveoaureus growing at 3,300 and 3,600 m.o.s.l, in the Páramo de Palacio, Chingaza, Colombia. Leaf apoplast proteins had MW between 3512 kDa. Electrophoretic patterns were different depending on the altitude and the time of sampling. However the observed variations could not be linked to changes in temperature or to the

  13. Mix proportion design of anti-freezing and anti-permeability low-strength concrete and its corresponding mechanical properties%低强度抗冻抗渗混凝土配合比设计及其力学特性

    Institute of Scientific and Technical Information of China (English)

    彭辉; 杨海宁; 刘绍林

    2012-01-01

    Through carefully choosing the mix proportion design of low-strength concrete,the anti-freezing,anti-perme- ability and mechanical properties of concrete were studied. The effects of optimal water-to-cement ratio, mixing amount of air-entraining agent on anti-freezing and anti-permeability characteristics of concrete were researched. Furthermore, the compressive strength of concrete under condition of saturated situation and natural curing were also studied respec- tively. The researches show that by using of mixing proper amount of air-entraining agent and choosing suitable water- to-cement ratio, the anti-freezing and anti-permeability of low-strength concrete can be obviously improved without re- ducing concrete strength and anti-permeability properties in severe cold areas in China.%通过对低强度混凝土配合比进行优化设计,并开展混凝土的抗冻、抗渗和力学等性能的试验研究。分别研究了最优水灰比、引气剂掺量等因素对混凝土抗冻性能的影响,并在上述条件下研究了其对强度和抗渗等性能的影响,以及饱和与自然养护条件下混凝土抗压强度变化特点。结果证明:在严寒地区,在满足工程结构混凝土强度和抗渗要求的情况下,即使配制低强度混凝土,通过掺适量引气剂和选用适当的水灰比能显著提高低强度混凝土在高寒干燥地区的抗冻耐久性。

  14. 双亲灭活原生质体融合技术在草菇耐低温菌株选育上的应用%Application of Inactivated Parental Strain Protoplasts Fusion Technology in Selection of Volvariella volvacea with Higher Antifreeze Capacity

    Institute of Scientific and Technical Information of China (English)

    陈建中; 祝子坪; 吴潇; 何建华; 蒋玮; 王金斌; 唐雪明

    2013-01-01

    为了选育耐低温草菇菌株,以草菇V23、V3552为亲本,采用酶解法制备原生质体,用紫外诱变、化学诱变两种方法对草菇菌株进行诱变,筛选到耐低温的突变株;然后利用紫外灭活(20 W,30 cm,110 s)和热灭活(50℃3 min)的双亲灭活标记法对突变株进行化学融合,结果表明在400 g/L的PEG6000、pH 8.0、融合时间30 min和融合温度32℃的条件下融合率最高,达到0.517%,共获得200个融合子。经过0℃低温筛选,最终获得15株草菇耐低温菌株,菌丝在0℃的耐冻能力提高了4.5倍。经出菇实验证明其子实体与出发菌株相比具有明显的耐低温性,液化现象明显推迟,说明该方法筛选出的菌株具有进一步应用开发的价值。%The protoplasts of Volvariella volvacea V23 and V3552 were prepared by enzymatic method, and then were taken mutagenesis by UV and chemical 2 methods. A fusant displaying higher antifreeze capacity, as compared to that of its parents, was obtained by PEG-induced fusion between UV-inactivated protoplasts of V3552 EMS and heat-inactivated protoplasts of V23 UV through low temperature ( 0℃) selection. The best fusion condition is gained at 400g/LPEG6000, pH 8.0, for 30min fusion time, at 32℃ fusion temperature. The fusion rate could be as high as 0�517%. And 200 fusants were obtained. Through screening with 0℃ low temperature, 15 Volvariella volvacea cold tolerant bacterial strains were obtained. The cold tolerant ability of hypha at 0℃ was improved by 4. 5 times. The results proved that the fruit displayed higher antifreeze capacity, as compared with bacterial strains; and the liquefaction phenomenon was obviously postponed. This indicated that strains screened by this method were of further development value.

  15. 乙二醇水溶液用于闭式冷却系统防冻的传热性能研究%THE RESEARCH OF THE HEAT TRANSFER PERFORMANCE WHEN ETHYLENE GLYCOL SOLUTION USED IN THE CLOSED COOLING SYSTEM ANTIFREEZE

    Institute of Scientific and Technical Information of China (English)

    章立新; 沈艳; 刘婧楠; 邹艳芳; 刘跃; 陈永保; 李瑞雄

    2013-01-01

    In the winter, ethylene glycol solution usually used in the closed cooling system instead of water as the antifreeze. Due to the changes in physical properties, its heat carrying capacity and convective heat transfer coefficient has declined. Based on the theory of closed-tower design, we studied the influence of the heat transfer different concentrations and different seasons to the Ethylene Glycol solution used in the closed cooling tower circulation; supposed that use a large diameter-thin walled tube, increase the flow rate of Ethylene Glycol solution cycle working fluid or increase the amount of ventilation rate, and reveals the variation in the different operating modes.%闭式水冷却系统在冬季常换用乙二醇水溶液作为防冻的循环工质,由于物性变化,其携热能力和对流换热系数比水都有所下降.本文基于闭塔设计理论,研究了不同浓度的乙二醇水溶液作为闭式冷却塔循环工质在不同季节中对换热的综合影响,提出了采用大管径薄壁管和加大循环工质流量及增加相应通风量等应对方法,并揭示了其在不同运行模式下的变化规律.

  16. 重组华根霉脂肪酶协同转谷氨酰胺酶提高冷冻面团抗冻发酵特性的研究%Improvement of Anti-freezing and Fermentation Properties of Frozen Dough by Recombinant Rhizopus chinensis Lipase Combined with Transglutaminase

    Institute of Scientific and Technical Information of China (English)

    李珍妮; 王宏兹; 黄卫宁; 张峦; 贾春利; 徐岩; RAYAS-DUARTE Patricia

    2011-01-01

    采用差示扫描量热仪和F3流变发酵仪研究重组华根霉脂肪酶(RCL)和转谷氨酰胺酶(TG)共同作用对冷冻面团抗冻发酵特性的影响。将面团于-18℃冻藏0、7、21、35d,结果发现:随着冻藏时间的延长,甘油含量有所降低,可冻结水含量增加;引入RCL和TG到冷冻面团中可以显著增加面团中的甘油含量,显著降低面团中可冻结水的含量,减少冰晶体的形成,并且可以提高酵母的存活数。F3流变发酵仪测定面团的发酵流变学特性,结果表明:RCL和TG同时作用可以显著降低冻藏对面团发酵高度的削弱作用,改善酵母的发酵性能和增加面团的持气率。%The effects of Rhizopus chinensis lipase(RCL) and transglutaminase(TG) on anti-freezing and fermentation properties of frozen dough during storage were investigated by using differential scanning calorimetry and F3 rheofermentometer.All doughs were stored at-18 ℃ for 7,21 days and 35 days.The results showed that glycerol content was decreased and freezable water content was increased with the increase of frozen storage time.RCL and TG could increase significantly glycerol content of frozen dough.The combined application of RCL and TG prevented the formation of ice crystals during frozen storage by lowering freezable water content in dough,and increased viable yeast cell count.Meanwhile,RCL and TG restricted frozen storage to deteriorate dough development,improved yeast fermentation activity,and increased gas retention of frozen dough.

  17. Anti-freeze coatings for the rotor blades of wind turbines; Anti-freeze Beschichtungen fuer Rotorblaetter von Windenergieanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Siegmann, K.; Kaufmann, A.; Hirayama, M.

    2006-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) takes a look at projects involving the development of suggestions for coatings for the rotor blades of wind turbines. The coatings are to reduce the formation of hoarfrost on the leading edges of the blades. Various coatings are described and the mechanisms involved in the formation of the frost and in keeping the blades as free as possible from frost are discussed. Global know-how on the subject is discussed, as is know-how available in Europe and Switzerland. Manufacturers, planning offices and installation operators are listed, as are research institutes who are dealing with this problem. In the summary, the authors stress the importance of choosing the coating most suitable for the actual climatic conditions at the wind turbine's location. A suggestion is made for further work in this area.

  18. Antifreeze in the hot core of Orion - First detection of ethylene glycol in Orion-KL

    CERN Document Server

    Brouillet, N; Lu, X -H; Baudry, A; Cernicharo, J; Bockelée-Morvan, D; Crovisier, J; Biver, N

    2015-01-01

    Comparison of their chemical compositions shows, to first order, a good agreement between the cometary and interstellar abundances. However, a complex O-bearing organic molecule, ethylene glycol (CH$_{2}$OH)$_{2}$, seems to depart from this correlation because it was not easily detected in the interstellar medium although it proved to be rather abundant with respect to other O-bearing species in comet Hale-Bopp. Ethylene glycol thus appears, together with the related molecules glycolaldehyde CH$_{2}$OHCHO and ethanol CH$_{3}$CH$_{2}$OH, as a key species in the comparison of interstellar and cometary ices as well as in any discussion on the formation of cometary matter. We focus here on the analysis of ethylene glycol in the nearest and best studied hot core-like region, Orion-KL. We use ALMA interferometric data because high spatial resolution observations allow us to reduce the line confusion problem with respect to single-dish observations since different molecules are expected to exhibit different spatial ...

  19. Conformation of antifreeze glycoproteins as determined from conformational energy calculations and fully assigned proton NMR spectra

    Energy Technology Data Exchange (ETDEWEB)

    Bush, C.A.; Rao, B.N.N.

    1986-05-01

    The /sup 1/H NMR spectra of AFGP's ranging in molecular weight from 2600 to 30,000 Daltons isolated from several different species of polar fish have been measured. The spectrum of AFGP 1-4 from Pagothenia borchgrevinki with an average of 30 repeating subunits has a single resonance for each proton of the glycotripeptide repeating unit, (ala-(gal-(..beta..-1..-->..3) galNAc-(..cap alpha..--O-)thr-ala)/sub n/. Its /sup 1/H NMR spectrum including resonances of the amide protons has been completely assigned. Coupling constants and nuclear Overhauser enhancements (n.O.e.) between protons on distant residues imply conformational order. The 2600 dalton molecular weight glycopeptides (AFGP-8) have pro in place of ala at certain specific points in the sequence and AFGP-8R of Eleginus gracilis has arg in place of one thr. The resonances of pro and arg were assigned by decoupling. The resonances of the carboxy and amino terminals have distinct chemical shifts and were assigned in AFGP-8 of Boreogadus saida by titration. n.O.e. between ..cap alpha..--protons and amide protons of the adjacent residue (sequential n.O.e.) were used in assignments of additional resonances and to assign the distinctive resonances of thr followed by pro. Conformational energy calculations on the repeating glycotripeptide subunit of AFGP show that the ..cap alpha..--glucosidic linkage has a fixed conformation while the ..beta..--linkage is less rigid. A conformational model for AFGP 1-4, which is based on the calculations has the peptide in an extended left-handed helix with three residues per turn similar to polyproline II. The model is consistent with CD data, amide proton coupling constants, temperature dependence of amide proton chemical shifts.

  20. Mechanism of antifreeze proteins action, based on Hierarchic theory of water and new ''clusterphilic'' interaction

    CERN Document Server

    Kaivarainen, A

    2001-01-01

    A basically new Hierarchic theory, general for solids and liquids (Kaivarainen, 2001, 2000, 1995, 1992), has been briefly described and illustrated by computer simulations on examples of water and ice. Full description of theory and its numerous applications are presented in series of articles at the arXiv of Los-Alamos (see http://arXiv.org/abs/physics/0102086). New clusterphilic interactions, intermediate between hydrophilic and hydrphobic, are introduced. They can be subdivided into: intramolecular - when water cluster is localized in the ''open'' states of big interdomain or intersubunit cavities and intermolecular clusterphilic interactions. Intermolecular clusterphilic interactions can be induced by very different macromolecules. The latter displays themselves in bordering of water cluster by macromolecules and forming so-called ''clustrons''. Clusterphilic interactions can play an important role in self-organization of biosystems, especially multiglobular allosteric enzymes, microtubules and the actin ...

  1. Intentional Ethylene Glycol Poisoning Increase after Media Coverage of Antifreeze Murders

    Directory of Open Access Journals (Sweden)

    Morgan, Brent

    2011-07-01

    Full Text Available Background: The media can have a profound impact on human behavior. A sensational murder by ethylene glycol (EG poisoning occurred in our state. The regional media provided extensive coverage of the murder. We undertook this investigation to evaluate our incidence of EG poisoning during the timeframe of before the first report linking a death to ethylene glycol to shortly after the first murder trial.Methods: Descriptive statistics and linear regression were used to describe and analyze the number of EG cases over time. A search of the leading regional newspaper’s archives established the media coverage timeline.Result: Between 2000 and 2004, our poison center (PC handled a steady volume of unintentional exposures to EG [range: 105–123 per year, standard deviation (SD=7.22]. EG exposures thought to be suicidal in intent increased from 12 cases in 2000 to 121 cases in 2004. In the 19 months prior to the first media report of this story, our PC handled a mean of 1 EG case with suicidal intent per month [range: 0–2, SD=.69]. In the month after the first media report, our PC handled 5 EG cases with suicidal intent. When media coverage was most intense (2004, our PC received a mean of 10 EG suicidal-intent calls per month [range: 5–17, SD=3.55]. Although uncommon, reports of malicious EG poisonings also increased during this same period from 2 in 2000 to 14 in 2004.Conclusion: Media coverage of stories involving poisonings may result in copycat events, applicable to both self-poisonings and concern for malicious poisonings. Poison centers should be aware of this phenomenon, pay attention to local media and plan accordingly if a poisoning event receives significant media coverage. The media should be more sensitive to the content of their coverage and avoid providing “how to” poisoning information. [West J Emerg Med. 2011;12(3:296-299.

  2. Antifreeze Proteins Enhance Survival of Cells in Cryopreservation - Substituting DMSO with RmAFP#1 in cryopreservation of cells

    OpenAIRE

    Henriksen, Beatriche L. E.; Kofod, Lotte; Gammeltoft, Karen A.; Christensen, Erik; Khan, Omar J.

    2015-01-01

    Cryopreservation is a useful method for preserving living cells and biological tissues. Dimethyl sulfoxide (DMSO) is considered the most effective cryoprotective agent (CPA) used in cryopreservation. DMSO helps to reduce ice crystallization within the cell and thus preventing cell death during the freezing and thawing process. However, DMSO has toxic effects on cells which are not only concentration dependent, but also temperature dependent. In this study, DMSO was substituted with an ins...

  3. Insect-attracting and antimicrobial properties of antifreeze for monitoring insect pests and natural enemies in stored corn

    Science.gov (United States)

    Insect infestations in stored grain cause extensive damage worldwide. Storage insect pests including the Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), Sitophilus spp. (Coleoptera: Curculionidae) and their natural enemies [e.g., Cephalonomia tarsalis (Ashmead) (Hymenopter...

  4. Inhibition of Gas Hydrate Nucleation and Growth: Efficacy of an Antifreeze Protein from the Longhorn BeetleRhagium mordax

    DEFF Research Database (Denmark)

    Perfeldt, Christine Malmos; Chua, Pei Cheng; Daraboina, Nagu;

    2014-01-01

    showed inhibition of hydrates compared to amino acids (l-valine and l-threonine) and the protein bovine serum albumin (BSA). This indicates that proteins or amino acids do not generally inhibit hydrate formation. The promising performance of RmAFP1 as a new green kinetic hydrate inhibitor could further...

  5. 果树抗寒防冻研究%Cold-resistant and An-tifreeze Research of Fruit Trees

    Institute of Scientific and Technical Information of China (English)

    吕凯

    2012-01-01

    Low-temperature freeze in-jury is a factor restraining introduction and domestication of fruit trees. Freeze injury types of fruit trees are introduced, technical measures for preventing fruit tree freeze injury proposed, remedies af-ter damage and the late recovery mea-sures introduced, so as to provide scien-tific references for studying cold resis-tance of fruit trees, and cultivating cold-resistant varieties.%低温冻害是影响果树引种和栽培的限制因子。介绍了果树的冻害类型,提出了预防果树冻害的技术措施,以及果树遭受冻害后的补救措施和后期的树体恢复措施,以期为果树抗寒性的研究、抗寒品种的选育提供科学的参考依据。

  6. Case Report of a Fatal Antifreeze Ingestion with a Record High Level and Impressive Renal Crystal Deposition

    Science.gov (United States)

    2016-01-01

    Ethylene glycol, methanol, and diethylene glycol are readily available in many household and commercially available products. While these alcohols are relatively nontoxic themselves, their acidic metabolites are toxic and can result in significant morbidity and mortality. Herein we report a lethal case of massive ethylene glycol ingestion in a suicide with a record high level (1254 mg/dL) and images of the histologic examination of the kidneys revealing impressive calcium oxalate crystal deposition. Autopsy findings also showed evidence of mild cerebral edema. PMID:27747109

  7. 透水性生态混凝土的抗冻研究%Research on anti-freezing of permeable ecological concrete

    Institute of Scientific and Technical Information of China (English)

    薛冬杰; 谭文菁

    2015-01-01

    The paper introduces the raw materials,proportional ratio,manufacturing and maintenance crafts of permeable ecological concrete, undertakes the frozen thawed test of the concrete,analyzes the pore structure of the permeable concrete in the frozen thawed conditions,and a-chieves some conclusion.%介绍了透水性生态混凝土制备的原材料、配合比、制作及养护工艺,并对透水性生态混凝土进行了冻融试验,分析了冻融条件下透水混凝土的孔隙结构,最终得出了一些有意义的结论。

  8. Testing antifreeze protein from the longhorn beetle Rhagium mordax as a kinetic gas hydrate inhibitor using a high-pressure micro differential scanning calorimeter

    DEFF Research Database (Denmark)

    Daraboina, Nagu; Perfeldt, Christine Malmos; von Solms, Nicolas

    2015-01-01

    Low dosage kinetic hydrate inhibitors are employed as alternatives to expensive thermodynamic inhibitors to manage the risk of hydrate formation inside oil and gas pipelines. These chemicals need to be tested at appropriate conditions in the laboratory before deployment in the field. A high...

  9. Summary on the antifreeze performance of conditioner improvement of saline soil%改良剂改良盐渍土的抗冻性综述

    Institute of Scientific and Technical Information of China (English)

    孟松松

    2016-01-01

    阐述了盐渍土的成因和分布特征,分析了粉煤灰、石膏、水泥、石灰等改良剂改善盐渍土抗冻性的研究进展,并提出改良剂改良进程中存在的缺陷,指出改良盐渍土的抗冻性能对加快盐渍土地区的开发建设具有重要意义.

  10. Potentially Dangerous Items for Your Pet

    Science.gov (United States)

    ... these are: Antifreeze Fabric softener sheets Ice melting products Insecticides Liquid potpourri Rat and mouse bait Various household cleaners (including bleach and toilet bowl cleaners) Swimming ...

  11. InterProScan Result: CK511306 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 00104 Antifreeze protein, type I Biological Process: homoiothermy (GO:0042309)|Molecular Function: ice binding (GO:0050825)|Biological Process: response to freezing (GO:0050826) ...

  12. InterProScan Result: BY918960 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 00104 Antifreeze protein, type I Biological Process: homoiothermy (GO:0042309)|Molecular Function: ice binding (GO:0050825)|Biological Process: response to freezing (GO:0050826) ...

  13. InterProScan Result: BY927519 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 00104 Antifreeze protein, type I Biological Process: homoiothermy (GO:0042309)|Molecular Function: ice binding (GO:0050825)|Biological Process: response to freezing (GO:0050826) ...

  14. InterProScan Result: BY928658 [KAIKOcDNA[Archive

    Lifescience Database Archive (English)

    Full Text Available 00104 Antifreeze protein, type I Biological Process: homoiothermy (GO:0042309)|Molecular Function: ice binding (GO:0050825)|Biological Process: response to freezing (GO:0050826) ...

  15. 发电厂直接空冷凝汽器的新型防冻监测系统设计%Design of Novel Anti-freezing Monitoring System for Direct Air Cooled Condenser in Power Plant

    Institute of Scientific and Technical Information of China (English)

    国建刚; 贾杰; 田振宇

    2014-01-01

    This paper analyzes tube bundle structure of A-type tower and its operating principle in direct air cooled condenser; it indicates that the lower end of downstream tube buddle is easier to freeze than that of upstream tube buddle in air cooled condenser. The utilization of temperature field online monitoring system of A-type tower tube bundles in direct air cooled condenser can effectively monitor freezing of air cooled con-denser. Finally, this paper expounds design and implementation scheme of temperature field online monitoring system of A-type tube bundles in direct air cooled condenser.%对直接空冷凝汽器A型塔管束结构及工作原理进行了分析,指出空冷凝汽器顺流管束的下端比逆流管束更容易结冰。采用空冷凝汽器温度场在线监测系统,可以有效监测空冷凝汽器冻结问题的发生,详细介绍了在线监测系统的设计方案。

  16. Shallow Weak Civil Type Refrigerator Heat Insolation,Moistureproof and the Ground of Antifreeze%浅淡土建式冷库的隔热、防潮与地坪防冻膨

    Institute of Scientific and Technical Information of China (English)

    吴敏

    2011-01-01

    土建式冷库因具有容量大、取材方便、造价低廉的特点,所以得到了广泛应用,文章重点对土建式冷库的隔热、防潮与地坪防冻膨的意义及建造过程进行了分析、阐述.

  17. 昆虫低温生物学: Ⅱ.冰核物质(冰核蛋白)和昆虫的耐冻性%Insect cryobiology: II. Ice nucleator agents (ice nucleator proteins) and insect antifreeze

    Institute of Scientific and Technical Information of China (English)

    李毅平; 龚和

    2000-01-01

    @@ 体系在低于熔点温度时才结冰的现象,叫过冷却(supercooling).体系开始结冰时的温度称为过冷却点(supercooling point, SCP).在适当的低温,体系内需存在一起始结冰的冰核,才能诱导冰晶产生,此物质称为冰核剂(ice nucleating agents, INA).昆虫体内各腔室充满组织液,各腔室(如消化系统和细胞内)因所含INA的冰核活性的不同,而使结冰的温度各异,所受低温伤害也不同.

  18. STYDY ON PERFORMANCE OF POLYCARBOXYLATE COMPOUNDED WITH ANTI-FREEZING ADMIXTURE%聚羧酸高效减水剂与防冻组分复合研究

    Institute of Scientific and Technical Information of China (English)

    王子明; 孙俊

    2008-01-01

    采用正交设计方法对聚羧酸系高效减水剂与防冻外加剂复合性能进行了研究.掺入聚羧酸系减水剂与防冻组分的胶砂试件中在(-15±1)℃环境下冷冻7d,并测定其胶砂抗压抗折强度.然后通过正交极差分析确定出防冻组分最佳配比并进行优化试验.进而进行单组分优化试验,比较不同防冻组分掺量对胶砂试件抗冻性的影响.

  19. Ethylene glycol poisoning

    Science.gov (United States)

    ... products, including: Antifreeze De-icing products Detergents Paints Cosmetics Note: This list may not be all-inclusive ... vein (IV) to reverse severe acidosis Antidotes that slow the formation of the poisonous by-products in ...

  20. Solution structures, dynamics, and ice growth inhibitory activity of peptide fragments derived from an antarctic yeast protein.

    Directory of Open Access Journals (Sweden)

    Syed Hussinien H Shah

    Full Text Available Exotic functions of antifreeze proteins (AFP and antifreeze glycopeptides (AFGP have recently been attracted with much interest to develop them as commercial products. AFPs and AFGPs inhibit ice crystal growth by lowering the water freezing point without changing the water melting point. Our group isolated the Antarctic yeast Glaciozyma antarctica that expresses antifreeze protein to assist it in its survival mechanism at sub-zero temperatures. The protein is unique and novel, indicated by its low sequence homology compared to those of other AFPs. We explore the structure-function relationship of G. antarctica AFP using various approaches ranging from protein structure prediction, peptide design and antifreeze activity assays, nuclear magnetic resonance (NMR studies and molecular dynamics simulation. The predicted secondary structure of G. antarctica AFP shows several α-helices, assumed to be responsible for its antifreeze activity. We designed several peptide fragments derived from the amino acid sequences of α-helical regions of the parent AFP and they also showed substantial antifreeze activities, below that of the original AFP. The relationship between peptide structure and activity was explored by NMR spectroscopy and molecular dynamics simulation. NMR results show that the antifreeze activity of the peptides correlates with their helicity and geometrical straightforwardness. Furthermore, molecular dynamics simulation also suggests that the activity of the designed peptides can be explained in terms of the structural rigidity/flexibility, i.e., the most active peptide demonstrates higher structural stability, lower flexibility than that of the other peptides with lower activities, and of lower rigidity. This report represents the first detailed report of downsizing a yeast AFP into its peptide fragments with measurable antifreeze activities.

  1. Bacterial Ice Crystal Controlling Proteins

    OpenAIRE

    Lorv, Janet S. H.; Rose, David R; Glick, Bernard R.

    2014-01-01

    Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. R...

  2. Bacterial ice crystal controlling proteins.

    Science.gov (United States)

    Lorv, Janet S H; Rose, David R; Glick, Bernard R

    2014-01-01

    Across the world, many ice active bacteria utilize ice crystal controlling proteins for aid in freezing tolerance at subzero temperatures. Ice crystal controlling proteins include both antifreeze and ice nucleation proteins. Antifreeze proteins minimize freezing damage by inhibiting growth of large ice crystals, while ice nucleation proteins induce formation of embryonic ice crystals. Although both protein classes have differing functions, these proteins use the same ice binding mechanisms. Rather than direct binding, it is probable that these protein classes create an ice surface prior to ice crystal surface adsorption. Function is differentiated by molecular size of the protein. This paper reviews the similar and different aspects of bacterial antifreeze and ice nucleation proteins, the role of these proteins in freezing tolerance, prevalence of these proteins in psychrophiles, and current mechanisms of protein-ice interactions. PMID:24579057

  3. Observation on the modifying activity of the protein from Elytrzgia repens rhizome for ice crystal

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In winter, spring and summer, the rhizome of wild Elytrzgia repens of Heilongjiang Province was selected to extract the soluble which whole protein and the apoplastic protein, and analyzed by SDS-PAGE. The result indicated that there were two specific polypeptides in two types protein from winter; their relative molecular weight were identified as 52 ku and 26 ku by analyzing software; the apoplastic protein from winter had the ability of modifing the growth of ice crystal which appeared hexagonal in shape observed with the phase-contrast photomicroscope. So the apoplastic protein from winter has the antifreeze characters and the 52 ku protein is more likely the antifreeze protein.

  4. Methanol incorporation in clathrate hydrates and the implications for oil and gas pipeline flow assurance and icy planetary bodies

    OpenAIRE

    Shin, Kyuchul; Udachin, Konstantin A.; Moudrakovski, Igor L.; Leek, Donald M.; Alavi, Saman; Ratcliffe, Christopher I.; Ripmeester, John A.

    2013-01-01

    One of the best-known uses of methanol is as antifreeze. Methanol is used in large quantities in industrial applications to prevent methane clathrate hydrate blockages from forming in oil and gas pipelines. Methanol is also assigned a major role as antifreeze in giving icy planetary bodies (e.g., Titan) a liquid subsurface ocean and/or an atmosphere containing significant quantities of methane. In this work, we reveal a previously unverified role for methanol as a guest in clathrate hydrate c...

  5. 46 CFR 189.25-20 - Fire-extinguishing equipment.

    Science.gov (United States)

    2010-10-01

    ... of extinguisher thoroughly. Recharge. Pump tank (water or antifreeze) Discharge. Clean hose and... hose and nozzle to be sure they are clear. 1 Dry chemical (cartridge-operated type) Examine pressure... chemical is free-flowing (not caked) and chamber contains full charge. Dry chemical (stored pressure...

  6. Chemical Emergency

    Science.gov (United States)

    ... waste collection facility. Many facilities accept pesticides, fertilizers, household cleaners, oil-based paints, drain and pool cleaners, antifreeze, and brake fluid. Some products can be recycled, which is better for our environment. If you have questions about how to dispose ...

  7. Complete recovery after massive ethylene glycol ingestion.

    Science.gov (United States)

    Curtin, L; Kraner, J; Wine, H; Savitt, D; Abuelo, J G

    1992-06-01

    We treated a 64-year-old man who recovered completely from a massive antifreeze ingestion with ethylene glycol levels well above those of previously described survivors. Rapid and aggressive treatment of the patient with recognized methods, including hemodialysis, resulted in the favorable outcome.

  8. Necrosis and haemorrhage of the putamen in methanol poisoning shown on MRI

    International Nuclear Information System (INIS)

    Methanol, a highly toxic substance, is used as an industrial solvent and in automobile antifreeze. Acute methanol poisoning produces severe metabolic acidosis and serious neurologic sequelae. We describe a 50-year-old woman with accidental methanol intoxication who was in a vegetative state. MRI showed haemorrhagic necrosis of the putamina and oedema in the deep white matter. (orig.)

  9. Necrosis and haemorrhage of the putamen in methanol poisoning shown on MRI

    Energy Technology Data Exchange (ETDEWEB)

    Kuteifan, K.; Gutbub, A.M.; Laplatte, G. [Service de Reanimation Medicale, Centre Hospitalier Louis Pasteur, Colmar (France); Oesterle, H.; Tajahmady, T. [Service de Neuroradiologie, Centre Hospitalier Louis Pasteur, Colmar (France)

    1998-03-01

    Methanol, a highly toxic substance, is used as an industrial solvent and in automobile antifreeze. Acute methanol poisoning produces severe metabolic acidosis and serious neurologic sequelae. We describe a 50-year-old woman with accidental methanol intoxication who was in a vegetative state. MRI showed haemorrhagic necrosis of the putamina and oedema in the deep white matter. (orig.) With 1 fig., 8 refs.

  10. Inhibition of ice recrystallization and cryoprotective activity of wheat proteins in liver and pancreatic cells.

    Science.gov (United States)

    Chow-Shi-Yée, Mélanie; Briard, Jennie G; Grondin, Mélanie; Averill-Bates, Diana A; Ben, Robert N; Ouellet, François

    2016-05-01

    Efficient cryopreservation of cells at ultralow temperatures requires the use of substances that help maintain viability and metabolic functions post-thaw. We are developing new technology where plant proteins are used to substitute the commonly-used, but relatively toxic chemical dimethyl sulfoxide. Recombinant forms of four structurally diverse wheat proteins, TaIRI-2 (ice recrystallization inhibition), TaBAS1 (2-Cys peroxiredoxin), WCS120 (dehydrin), and TaENO (enolase) can efficiently cryopreserve hepatocytes and insulin-secreting INS832/13 cells. This study shows that TaIRI-2 and TaENO are internalized during the freeze-thaw process, while TaBAS1 and WCS120 remain at the extracellular level. Possible antifreeze activity of the four proteins was assessed. The "splat cooling" method for quantifying ice recrystallization inhibition activity (a property that characterizes antifreeze proteins) revealed that TaIRI-2 and TaENO are more potent than TaBAS1 and WCS120. Because of their ability to inhibit ice recrystallization, the wheat recombinant proteins TaIRI-2 and TaENO are promising candidates and could prove useful to improve cryopreservation protocols for hepatocytes and insulin-secreting cells, and possibly other cell types. TaENO does not have typical ice-binding domains, and the TargetFreeze tool did not predict an antifreeze capacity, suggesting the existence of nontypical antifreeze domains. The fact that TaBAS1 is an efficient cryoprotectant but does not show antifreeze activity indicates a different mechanism of action. The cryoprotective properties conferred by WCS120 depend on biochemical properties that remain to be determined. Overall, our results show that the proteins' efficiencies vary between cell types, and confirm that a combination of different protection mechanisms is needed to successfully cryopreserve mammalian cells.

  11. PROPERTIES OF LIGHTWEIGHT MASONRY MORTARS WITH HOLLOW GLASS MICROSPHERES FOR WINTER CONDITIONS

    Directory of Open Access Journals (Sweden)

    Semenov Vyacheslav Sergeevich

    2012-10-01

    reduction fillers (such as inflated pearlite, vermiculite etc. demonstrate low strength properties, as such fillers have a high water content. Hollow glass (or ceramic microspheres are known as efficient fillers for lightweight mortars. Multiple research undertakings contain information on the masonry mortar that has the following properties: average density of dry mortar - 450 kg/m3, thermal conductivity factor - 0.17 W/(m·°C, compressive strength at the age of 28 days - 3.2 MPa, water retention rate - over 90 %. The climatic conditions of Russia determine the need to perform masonry works at negative temperatures. Adding antifreeze admixtures is an easy and cheap method that guarantees hydration of the Portland-cement at negative temperatures. The subject of this research covers masonry mortars that have a 15 % hollow glass microsphere content and antifreeze admixtures. Contemporary antifreeze admixtures are multifunctional. Therefore, traditional antifreeze admixtures such as sodium chloride, calcium chloride, sodium nitrite, sodium nitrate, sodium formate, potash were used in the research. The per-cent content of antifreeze admixtures was calculated. The following properties of masonry mortars with a 15 % content of hollow glass microspheres and antifreeze admixtures were identified: average mortar and mortar mixture density, setting time, water retention, compressive and bending strength, and water absorption. Standard research methods were employed. Every mortar has an 8 cm mobility. The benchmark mixture has an average density of 1.085 kg/ m3, average cement stone density of 980 kg/m3, compressive strength at the age of 28 days - 19.8 MPa, water retention rate - 97 %, setting time - 4.5 hours. The attention was driven to the strength analysis of mortars with hollow glass microspheres and antifreeze admixtures at positive and negative temperatures. The authors proved that antifreeze admixtures demonstrated a negative influence on the strength and setting

  12. Experimental study on low temperature performance of polymer drilling mud agents

    Institute of Scientific and Technical Information of China (English)

    ZHAN Jiajia; XU Huiwen; CAI Hongliang

    2009-01-01

    Drilling fluid additives has a major impact on rheology behavior and other performances of the drilling fluid. The key to low temperature drilling fluids is choosing antifreeze and polymer agent which have a strong ability in resisting low temperature. On the basis of determining glycol as antifreeze agent, the low-temperature-performance and capacities of anti-collapse of regular validity mud agents have been studied, the mechanism of anti-caving of the partially hydrolyzed polyacrylamide (PHPA), polypropylene potassium (KPA) and PAC-141 polymer additives have been also analyzed. A pilot study of compatibility between ethylene glycol and the polymers has educed that the polymers, ethylene glycol and inorganic salt are compatible, and they can significantly reduce the freezing point of drilling fluid. Anti-collapse ability of the drilling mud is the results of synergistic action among the agents.

  13. Bioinspiration From Nano to Micro Scales

    CERN Document Server

    2012-01-01

    Methods in bioinspiration and biomimicking have been around for a long time. However, due to current advances in modern physical, biological sciences, and technologies, our understanding of the methods have evolved to a new level. This is due not only to the identification of mysterious and fascinating phenomena but also to the understandings of the correlation between the structural factors and the performance based on the latest theoretical, modeling, and experimental technologies. Bioinspiration: From Nano to Micro Scale provides readers with a broad view of the frontiers of research in the area of bioinspiration from the nano to macroscopic scales, particularly in the areas of biomineralization, antifreeze protein, and antifreeze effect. It also covers such methods as the lotus effect and superhydrophobicity, structural colors in animal kingdom and beyond, as well as behavior in ion channels. A number of international experts in related fields have contributed to this book, which offers a comprehensive an...

  14. Ophthalmic findings in two cases of methanol optic neuropathy with relapsed vision disturbance

    Institute of Scientific and Technical Information of China (English)

    Xiu-Juan; Zhao; Lin; Lu; Mei; Li; Hui; Yang

    2015-01-01

    <正>Dear Sir,We hereby report two cases of methanol optic neuropathy with relapsed vision disturbance.Methanol intoxication appears after accidental or suicidal oral ingestion of industrial solvents or cleaning and antifreeze liquids or occasionally is due to fraudulent adulteration of wine or other alcoholic beverages.Its ingestion can cause severe visual disturbances and the outcomes of visual disturbances vary diffusively.Some completely or partially recovered,and some suffered

  15. “Fuzzy oil drop” model applied to individual small proteins built of 70 amino acids

    OpenAIRE

    Prymula, Katarzyna; Sałapa, Kinga; Roterman, Irena

    2010-01-01

    Abstract The proteins composed of short polypeptides (about 70 amino acid residues) representing the following functional groups (according to PDB notation): growth hormones, serine protease inhibitors, antifreeze proteins, chaperones and proteins of unknown function, were selected for structural and functional analysis. Classification based on the distribution of hydrophobicity in terms of deficiency/excess as the measure of structural and functional specificity is presented. The ...

  16. New Adhesive Materinl for Construction Joint of Tunnel Lining

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The new adhesive material for the construction joints of tunnel lining(named as SZC) was studied based on the structural characteristics of interfaces and the characteristic of bonding construction,and the performance indexes were verified by tests. The experimental results show that the adhesive capability of interface is improved effectively by using SZC material, the properties, such as anti-freezing, erosion-resistance and anti-shrinkage are improved greatly as well as durability.

  17. A Study of the Energy Efficiency of Hadronic Reactors of Molecular Type

    OpenAIRE

    Aringazin, A. K.; Santilli, R. M.

    2001-01-01

    In this paper, we introduce an estimate of the "commercial efficiency" of Santilli's hadronic reactors of molecular type (Patented and International Patents Pending) which convert a liquid feedstock (such as automotive antifreeze and oil waste, city or farm liquid waste, crude oil, etc.) into the clean burning magnegas plus heat acquired by the liquid feedstock. The "commercial efficiency" is defined as the ratio between the total energy output (energy in magnegas plus heat) and the electric ...

  18. Methoden zur Immobilisierung von Proteinen auf Polyurethan- und Goldoberflächen und ihr Einfluss auf Konformation und Aktivität der Proteine

    OpenAIRE

    Kreider, Alexej

    2014-01-01

    In recent years anti-freeze proteins became the focus of interest for materials science due to their ice-crystall-growth inhibiting properties, recrystallisation properties and ice-crystall structuring properties. The transfer of these properties to surfaces by means of a molecular biomimetic approach is the challenge as well as motivation of this work. Here, the molecular bionic approach is based on chemical immobilization methods of proteins to solid surfaces. Thus, the first question of th...

  19. Efficient on-site degradation of high concentration of spent deicing fluids: A laboratory study. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Strong, J.M. [Oak Ridge National Lab., TN (United States); Waltz, M. [REMTECH, Bridgeville, PA (United States)

    1997-10-01

    The on-site treatment of antifreeze compounds and aircraft deicing fluids (ethylene glycol and propylene glycol) will reduce disposal costs, decrease environmental impact, minimize the potential for additional spills/contamination and meet the goals of pollution prevention by reducing the amount of hazardous materials generated. The authors have identified bacteria that can degrade 1-10% glycol waste at room temperatures of ca. 23C. A second subculture was isolated that could degrade glycol waste at ca. 4C.

  20. Inhibition of Ice Growth and Recrystallization by Zirconium Acetate and Zirconium Acetate Hydroxide

    OpenAIRE

    Ortal Mizrahy; Maya Bar-Dolev; Shlomit Guy; Ido Braslavsky

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These o...

  1. The Effects of AFGP Addition and Removing Protocol of CPA on Vitrification Cryopreservation of Osteoblasts

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 Introduction Vitrification is an effective method for cryopreservation of cells~([1, 2]). However, cells are usually damaged due to the osmotic injury caused by the higher concentrations of cryoprotective agents (CPA) during CPA removing. The ice recrystallization in thawing solution can also hurt cells seriously. Antifreeze glycoprotein (AFGPs) is extremely efficient at inhibiting ice recrystallization~([3]).The effects of Removing protocols and AFGP on cell viability were investigated. 2 Materials and M...

  2. Solute effects on ice recrystallization: an assessment technique.

    Science.gov (United States)

    Knight, C A; Hallett, J; DeVries, A L

    1988-02-01

    Reliable assessment of the effect of a solute upon ice recrystallization is accomplished with "splat cooling," the impaction of a small solution droplet onto a very cold metal plate. The ice disc has extremely small crystals, and recrystallization can be followed without confusing effects caused by grain nucleation. This method confirms the exceptionally strong recrystallization inhibition effect of antifreeze protein from Antarctic fish and shows that grain growth rate is a sensitive function of both grain size and solute concentration.

  3. Probing the Biomimetic Ice Nucleation Inhibition Activity of Poly(vinyl alcohol) and Comparison to Synthetic and Biological Polymers

    OpenAIRE

    Congdon, Thomas; Dean, Bethany T.; Kasperczak-Wright, James; Biggs, Caroline I.; Notman, Rebecca; Gibson, Matthew I.

    2015-01-01

    Nature has evolved many elegant solutions to enable life to flourish at low temperatures by either allowing (tolerance) or preventing (avoidance) ice formation. These processes are typically controlled by ice nucleating proteins or antifreeze proteins, which act to either promote nucleation, prevent nucleation or inhibit ice growth depending on the specific need, respectively. These proteins can be expensive and their mechanisms of action are not understood, limiting their translation, especi...

  4. 昆虫抗冻蛋白基因Mpafpl49对棉花内生菌的转化及转化菌回接棉花的耐寒性初探

    Institute of Scientific and Technical Information of China (English)

    梁娜; 赵佳; 赵洁; 马纪

    2011-01-01

    Objective l This study aimed to expIore a rapid and effective method for improving coId toIerance of cotton pIant by inocuIating the endophyte of cotton that was transformed by an insect antifreeze protein gene Mpafpl49 from the desert beetIe Microdera punctipennis. L Method l Recombinant pIasmid expressing antifreeze protein and green fIuorescence fusion protein was constructed based on shuttIe pIasmid Pbe23 The recombinant pIasmid was eIectronicaIIy transformed into endophyte Ml7, and then the transformed endophyte was inocuIated into cotton seedIing3 cotton seedIings with and without transformed endophyte inocuIation were subject to fIuorescence observation and to coId treatment at - Lc for a period of time. The reIative conductivity of cotton Ieaves was determined after l4 h at - l C. L Result l The pIasmid Pbe2 -Mpafpl49 - gfp is transformed into bacillus subtilis Ml7 successfuIIy and the transformed endophytes showed increased freeze toIerance. The cotton seedIings carrying the transformed Ml7 showed significant Iower reIative conductivity compared with the controI cotton, indicating that the antifreeze protein expressed by the transformed endophyte exerts certain IeveI of cryoprotective effect, aIthough there was no obvious difference in the fIuorescent intensity between the inocuIated and the controI cotton. L conclusion l The coId toIerance of cotton pIant can be improved rapidIy by inocuIating endophyte carrying an insect antifreeze protein gene. The IocaIization of the inocuIated enophyte in cotton was not distinguishabIe by observing the green fIuorescence due to the endogenous fIuoresce of cotton pIant.

  5. X-ray imaging of radioresistant Deinococcus radiodurans

    Science.gov (United States)

    Takemoto, K.; Narumi, I.; Satoh, K.; Namba, H.; Kihara, H.

    2009-09-01

    Deinococcus radiodurans has been known to withstand radiation levels up to 1,000 times than that would kill normal human cells. To cope radiation damage during soft X-ray observation of living cells, D. radiodurans incubated with tellurium oxyanions was used as the X-ray microscopy sample. The first observation was successfully performed. In combination of antifreeze solution and subzero temperature, along with carbon window, the cell observation will be more closely to the living condition.

  6. 氯盐阻锈型防冻剂中引气组分掺量对混凝土性能影响研究

    Institute of Scientific and Technical Information of China (English)

    王国东

    2011-01-01

    Now in concrete construction of winter antifreeze universal use ,this article targetes on anti-freezing concrete, Focusing on the chlorine salt resistance rust type in antifreeze air-entraining components of.with the introduction of concrete intensity gas%如今防冻剂在混凝土冬季施工中普遍采用,本文有针对性的对混凝土防冻剂进行研究,着重对氯盐阻锈型防冻剂中引气组分的研究。随着气体的引入对混凝土强度发展造成一定的影响。通过大量的试验结果表明,防冻剂中引气组分对混凝土耐久性和工作性均有一定的改善作用,并提出在混凝土中掺入引气剂的必要性。

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

    Directory of Open Access Journals (Sweden)

    Chen He

    2015-12-01

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

  8. Lessons from nature for preservation of mammalian cells, tissues, and organs.

    Science.gov (United States)

    Brockbank, Kelvin G M; Campbell, Lia H; Greene, Elizabeth D; Brockbank, Matthew C G; Duman, John G

    2011-03-01

    The study of mechanisms by which animals tolerate environmental extremes may provide strategies for preservation of living mammalian materials. Animals employ a variety of compounds to enhance their survival, including production of disaccharides, glycerol, and antifreeze compounds. The cryoprotectant glycerol was discovered before its role in amphibian survival. In the last decade, trehalose has made an impact on freezing and drying methods for mammalian cells. Investigation of disaccharides was stimulated by the variety of organisms that tolerate dehydration stress by accumulation of disaccharides. Several methods have been developed for the loading of trehalose into mammalian cells, including inducing membrane lipid-phase transitions, genetically engineered pores, endocytosis, and prolonged cell culture with trehalose. In contrast, the many antifreeze proteins (AFPs) identified in a variety of organisms have had little impact. The first AFPs to be discovered were found in cold water fish; their AFPs have not found a medical application. Insect AFPs function by similar mechanisms, but they are more active and recombinant AFPs may offer the best opportunity for success in medical applications. For example, in contrast to fish AFPs, transgenic organisms expressing insect AFPs exhibit reduced ice nucleation. However, we must remember that nature's survival strategies may include production of AFPs, antifreeze glycolipids, ice nucleators, polyols, disaccharides, depletion of ice nucleators, and partial desiccation in synchrony with the onset of winter. We anticipate that it is only by combining several natural low temperature survival strategies that the full potential benefits for mammalian cell survival and medical applications can be achieved. PMID:21191664

  9. 盐化物融冰雪沥青路面盐分溶析试验研究%Experiment Research of Asphalt Mixture with Salt for Melting Snow and Ice

    Institute of Scientific and Technical Information of China (English)

    李娜; 王海峰; 徐希娟

    2014-01-01

    路面的抗滑性能是保证车辆安全行驶的关键因素,盐化物融冰雪沥青路面的冻结抑制作用主要取决于路面内冻结抑制成分的含量及路面表面的盐分析出量。通过自然浸泡溶出量法研究盐分随时间的溶析规律,结果表明:盐化物的溶析分为三个阶段,初期溶析速度较快,第二阶段为匀速溶出阶段,后期溶液浓度趋于稳定,通过溶液浓度可间接评价融冰雪效果。%Anti-slip Performance of pavement is the key factor to ensure the safe driving of vehicles, anti-freezing effect of salt anti-freezing asphalt pavement depends on the content of anti-freezing element in pavement and surface salt output. Through the natural immersion dissolved amount method to study the solventing-outlaw of salt with time, the results show that:dissolving salt can be divided into three stages, the initial dilution rate is fast, the second stage stripping stage is uniform, the late solution concentration tends to be stable, melting ice and snow effect is evaluated indirectly by the concentration of the solution.

  10. Application of Orthogonal Experiment in Compound Admixture of Freezing Mine Shaft Lining Concrete%正交法在冻结井壁砼复合外加剂试验中的应用

    Institute of Scientific and Technical Information of China (English)

    宗翔; 徐颖; 李寅珺

    2012-01-01

    In order to achieve the setting and hardening of mine shaft lining concrete under the minus temperature in freezing construction and to meet the demands of every performance of concrete, the technique of compounding air entraining admixture and antifreezing admixture and early strength water reducing admixture was applied in this research. Based on the Orthogonal experimental design, several mix proportions of compound admixture for early strength liquid mine shaft lining concrete were developed in the laboratory. The data collected in this research provide reference for the optimum mix proportion of the adulteration quantity of the concrete admixture. The results show that the 2. 1% amount of compound antifreezing admixture achieves favorable effects of liquid,early strength,freezing prevention and antifreezing.%为了使冻结施工井壁混凝土能够在负温条件下凝结与硬化,并满足其各项性能要求,采用引气剂+防冻剂+早强减水剂复合的技术路线,通过正交试验设计复配了适应冻结施工早强流态井壁混凝土的复合外加剂.通过试验分析最终确定各组分掺量之间的最佳配比.复合外加剂的掺量为2.1%,可起到流态、早强、防冻及抗冻的作用.

  11. Ice-binding proteins that accumulate on different ice crystal planes produce distinct thermal hysteresis dynamics.

    Science.gov (United States)

    Drori, Ran; Celik, Yeliz; Davies, Peter L; Braslavsky, Ido

    2014-09-01

    Ice-binding proteins that aid the survival of freeze-avoiding, cold-adapted organisms by inhibiting the growth of endogenous ice crystals are called antifreeze proteins (AFPs). The binding of AFPs to ice causes a separation between the melting point and the freezing point of the ice crystal (thermal hysteresis, TH). TH produced by hyperactive AFPs is an order of magnitude higher than that produced by a typical fish AFP. The basis for this difference in activity remains unclear. Here, we have compared the time dependence of TH activity for both hyperactive and moderately active AFPs using a custom-made nanolitre osmometer and a novel microfluidics system. We found that the TH activities of hyperactive AFPs were time-dependent, and that the TH activity of a moderate AFP was almost insensitive to time. Fluorescence microscopy measurement revealed that despite their higher TH activity, hyperactive AFPs from two insects (moth and beetle) took far longer to accumulate on the ice surface than did a moderately active fish AFP. An ice-binding protein from a bacterium that functions as an ice adhesin rather than as an antifreeze had intermediate TH properties. Nevertheless, the accumulation of this ice adhesion protein and the two hyperactive AFPs on the basal plane of ice is distinct and extensive, but not detectable for moderately active AFPs. Basal ice plane binding is the distinguishing feature of antifreeze hyperactivity, which is not strictly needed in fish that require only approximately 1°C of TH. Here, we found a correlation between the accumulation kinetics of the hyperactive AFP at the basal plane and the time sensitivity of the measured TH.

  12. Temperature Effect on Single Bubble Sonoluminescence

    Institute of Scientific and Technical Information of China (English)

    卢美军; 陈伟中; 申建华; 王文杰; 李晟琼

    2002-01-01

    Experiments of the temperature effect on single bubble sonoluminescence (SBSL) are performed with a mixture of water and anti-freeze. Since experiments of constant pressure (keeping sound pressure constant) are not feasible for a wide temperature range, experiments of constant luminance (keeping light intensity stable), which reflect pure sensitivity of SBSL to temperature, are investigated. The results show that lower temperature needs less pressure to obtain the same light intensity, which means that lower temperature is better for SBSL. Numerical calculations show a qualitative agreement with experiments.

  13. Bay-scale population structure in coastal Atlantic cod in Labrador and Newfoundland, Canada

    DEFF Research Database (Denmark)

    Ruzzante, D.E.; Wroblewski, J.S.; Taggart, C.T.;

    2000-01-01

    Polymorphisms at five microsatellite DNA loci provide evidence that Atlantic cod Gadus morhua inhabiting Gilbert Bay, Labrador are genetically distinguishable from offshore cod on the north- east Newfoundland shelf and from inshore cod in Trinity Bay, Newfoundland. Antifreeze activity in the blood...... of population structure suggest that important barriers to gene flow exist among five components that include two inshore (Gilbert and Trinity Bay) and three offshore cod aggregations on the north-east Newfoundland Shelf and the Grand Bank. D-A and D-SW estimates of genetic distance that involve Gilbert Bay cod...

  14. Unusual Clinical Presentation of Ethylene Glycol Poisoning: Unilateral Facial Nerve Paralysis

    Directory of Open Access Journals (Sweden)

    Eray Eroglu

    2013-01-01

    Full Text Available Ethylene glycol (EG may be consumed accidentally or intentionally, usually in the form of antifreeze products or as an ethanol substitute. EG is metabolized to toxic metabolites. These metabolites cause metabolic acidosis with increased anion gap, renal failure, oxaluria, damage to the central nervous system and cranial nerves, and cardiovascular instability. Early initiation of treatment can reduce the mortality and morbidity but different clinical presentations can cause delayed diagnosis and poor prognosis. Herein, we report a case with the atypical presentation of facial paralysis, hematuria, and kidney failure due to EG poisoning which progressed to end stage renal failure and permanent right peripheral facial nerve palsy.

  15. Storage products and tissue interaction in the ovule of Pinus silvestris (L.

    Directory of Open Access Journals (Sweden)

    F. M. Engels

    2014-02-01

    Full Text Available The organel-sequence in ovular cells of Pinus silvestris was investigated by light- and electronmicroscopy during the post-pollination and pre-fertilization period. Changes in starch and lipid storage suppose starch to be a pool for lipid synthesis and a reserve for ovule development. The base nucellus plays an important role in the distribution of metabolites all over the ovular tissues. Lipid, starch and callose are of interest for the cells to protect them against low temperatures by means of isolation, antifreeze and plug formation respectively.

  16. A novel psychrophilic Janthinobacterium lividum MMPP4 isolated from Manimahesh Lake of Chamba District of Himachal Pradesh, India

    OpenAIRE

    Ranjana Suman; Parul Sharma; Sonika Gupta; Anuradha Sourirajan; Kamal Dev

    2015-01-01

    We isolated psychrophilic bacterial strains from high altitude (elevation 13,390 ft) Manimahesh Lake of Chamba District of Himachal Pradesh. Based on phenotypic characteristics and growth appearance at 4ºC, four bacterial isolates (MMPP2, MMPP4, MMPP5, and MMPP7) were selected and showed optimum growth at 20ºC and no growth was detected at 25ºC.  Qualitative assay showed that cell free medium of MMPP4 prevent inhibition of freezing (antifreeze activity) as determined...

  17. Moving sidewalk for snow board gelande; Snow board gerendemuke ugoku hodo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-04-20

    This is a moving sidewalk installed on the indoor type artificial snow board gelande at Shigenobu-cho, Ehime prefecture, constructed for the first time in Shikoku. It carries snow boarders in gelande. The main specifications are as follows. Type: 800 type. Sidewalk width: 600mm. Length: 76.0m. Speed: 30m/min. Inclination angle: 13 degrees (inclination type). The features are as follows. (1) The tread is rubber-belt made and skid-resistant if it gets wet. (2) It is equipped with the each-part antifreezer, considering the snow quality and the environment where it is used at low temperature. (translated by NEDO)

  18. Data from thermal testing of the Open Source Cryostage

    DEFF Research Database (Denmark)

    Buch, Johannes Lørup; Ramløv, Hans

    2016-01-01

    The data presented here is related to the research article "An open source cryostage and software analysis method for detection of antifreeze activity" (Buch and Ramløv, 2016) [1]. The design of the Open Source Cryostage (OSC) is tested in terms of thermal limits, thermal efficiency and electrical...... efficiency. This article furthermore includes an overview of the electrical circuitry and a flowchart of the software program controlling the temperature of the OSC. The thermal efficiency data is presented here as degrees per volt and maximum cooling capacity....

  19. PERFORMANCE INVESTIGATION OF SLINKY HEAT EXCHANGER FOR SOLAR ASSISTED GROUND SOURCE HEAT PUMP

    OpenAIRE

    ÖZSOLAK, Onur; ESEN, Mehmet

    2014-01-01

    In the following study, 12 m2 test chamber was heated by solar and ground source heat pump under the physical conditions of Elazığ. In order to place slinky heat exchanger pipes, a hole was dug with 1 meter width, 2 meters depth and 15 meters length. Slinky pipes were put horizontally in the hole and water-antifreeze mixture was circulated with the circulating pump in the slinky heat exchanger. The heat taken from the ground was transferred into the environment to be heated through the heat p...

  20. Ice-active proteins from New Zealand snow tussocks, Chionochloa macra AND C. rigida.

    Science.gov (United States)

    Wharton, D A; Selvanesan, L; Marshall, C J

    2010-01-01

    The ice active protein profile of New Zealand snow tussocks Chionochloa macra and C. rigida consisted of ice nucleation activity but no antifreeze or recrystallization inhibition activity. The ice nucleation activity was similar in the two species, despite them being collected at different altitudes and at different times. The activity is intrinsic to the plant and is associated with the surface of the leaves. Snow tussocks collect water from fog. Nucleation sites on the surface of their leaves may aid the efficiency of this process. PMID:20919453

  1. Data from thermal testing of the Open Source Cryostage.

    Science.gov (United States)

    Buch, Johannes Lørup; Ramløv, Hans

    2016-09-01

    The data presented here is related to the research article "An open source cryostage and software analysis method for detection of antifreeze activity" (Buch and Ramløv, 2016) [1]. The design of the Open Source Cryostage (OSC) is tested in terms of thermal limits, thermal efficiency and electrical efficiency. This article furthermore includes an overview of the electrical circuitry and a flowchart of the software program controlling the temperature of the OSC. The thermal efficiency data is presented here as degrees per volt and maximum cooling capacity. PMID:27508238

  2. Ethylene glycol, hazardous substance in the household.

    Science.gov (United States)

    Patocka, Jirí; Hon, Zdenek

    2010-01-01

    Ethylene glycol is a colorless, odorless, sweet-tasting but poisonous type of alcohol found in many household products. The major use of ethylene glycol is as an antifreeze in, for example, automobiles, in air conditioning systems, in de-icing fluid for windshields, and else. People sometimes drink ethylene glycol mistakenly or on purpose as a substitute for alcohol. Ethylene glycol is toxic, and its drinking should be considered a medical emergency. The major danger from ethylene glycol is following ingestion. Due to its sweet taste, peoples and occasionally animals will sometimes consume large quantities of it if given access to antifreeze. While ethylene glycol itself has a relatively low degree of toxicity, its metabolites are responsible for extensive cellular damage to various tissues, especially the kidneys. This injury is caused by the metabolites, glycolic and oxalic acid and their respective salts, through crystal formation and possibly other mechanisms. Toxic metabolites of ethylene glycol can damage the brain, liver, kidneys, and lungs. The poisoning causes disturbances in the metabolism pathways, including metabolic acidosis. The disturbances may be severe enough to cause profound shock, organ failure, and death. Ethylene glycol is a common poisoning requiring antidotal treatment. PMID:20608228

  3. Mechanical interactions between ice crystals and red blood cells during directional solidification.

    Science.gov (United States)

    Ishiguro, H; Rubinsky, B

    1994-10-01

    Experiments in which red blood cells were frozen on a directional solidification stage under a microscope show that there is a mechanical interaction between ice crystals and cells in which cells are pushed and deformed by the ice crystals. The mechanical interaction occurs during freezing of cells in physiological saline and is significantly inhibited by the addition of 20% v/v glycerol to the solution. The addition of osmotically insignificant quantities of antifreeze proteins from the winter flounder or ocean pout to the physiological saline with 20% v/v glycerol generates strong mechanical interactions between the ice and the cells. The cells were destroyed during freezing in physiological saline, survived freezing in physiological saline with glycerol, and were completely destroyed by the addition of antifreeze proteins to the solution with glycerol. The difference in cell survival through freezing and thawing appears to be related, in part, to the habit of ice crystal growing in the suspension of red blood cells and the nature of mechanical interaction between the ice crystal and the cells. This suggests that mechanical damage may be a factor during cryopreservation of cells.

  4. Experimental study on C20 no-fines pervious concrete made by recycled aggregate%再生骨料制备C20无砂混凝土的试验研究

    Institute of Scientific and Technical Information of China (English)

    左文銮; 魏勇; 范建峰; 陈雷

    2014-01-01

    主要以废弃混凝土制得再生骨料,通过试验研究不同水胶比,不同颗粒级配的再生骨料制备的无砂混凝土的力学性能,透水性能,抗冻性能。试验结果表明由再生骨料制备的C20无砂混凝土的性能和水胶比及再生骨料的级配相关,其强度满足一般道路基层的需求,透水性能和抗冻性能良好。%The concrete mainly made of recycled aggregate through the experiments to research the mechanics performance,the water-proof performance and the antifreeze performance of the recycled concrete under the different water/cement ratio and the different particle size distribution of the recycled aggregate.The result showed that the performance of the recycled concrete was about to the water/cement ratio and the different particle size distribution of the recycled aggregate,and it met the needs of the general road base on its strength,it also has good waterproof performance and antifreeze performance.

  5. Latent Ice Recrystallization Inhibition Activity in Nonantifreeze Proteins: Ca2+-Activated Plant Lectins and Cation-Activated Antimicrobial Peptides.

    Science.gov (United States)

    Mitchell, Daniel E; Gibson, Matthew I

    2015-10-12

    Organisms living in polar regions have evolved a series of antifreeze (glyco) proteins (AFGPs) to enable them to survive by modulating the structure of ice. These proteins have huge potential for use in cellular cryopreservation, ice-resistant surfaces, frozen food, and cryosurgery, but they are limited by their relatively low availability and questions regarding their mode of action. This has triggered the search for biomimetic materials capable of reproducing this function. The identification of new structures and sequences capable of inhibiting ice growth is crucial to aid our understanding of these proteins. Here, we show that plant c-type lectins, which have similar biological function to human c-type lectins (glycan recognition) but no sequence homology to AFPs, display calcium-dependent ice recrystallization inhibition (IRI) activity. This IRI activity can be switched on/off by changing the Ca2+ concentration. To show that more (nonantifreeze) proteins may exist with the potential to display IRI, a second motif was considered, amphipathicity. All known AFPs have defined hydrophobic/hydrophilic domains, rationalizing this choice. The cheap, and widely used, antimicrobial Nisin was found to have cation-dependent IRI activity, controlled by either acid or addition of histidine-binding ions such as zinc or nickel, which promote its amphipathic structure. These results demonstrate a new approach in the identification of antifreeze protein mimetic macromolecules and may help in the development of synthetic mimics of AFPs.

  6. Ice-active proteins and cryoprotectants from the New Zealand alpine cockroach, Celatoblatta quinquemaculata.

    Science.gov (United States)

    Wharton, D A; Pow, B; Kristensen, M; Ramløv, H; Marshall, C J

    2009-01-01

    Celatoblatta quinquemaculata is moderately freezing tolerant. We have investigated low and high molecular weight compounds that may be associated with its survival. Glycerol and trehalose were identified as potential cryoprotectants, with trehalose at the higher concentration. Trehalose was at its highest concentration in late autumn, during the periods sampled. Water contents declined with time and were significantly lower in late autumn than in late summer. No thermal hysteresis activity was detected in haemolymph or in extracts of the head, muscles and the fat body. Extracts of the Malpighian tubules showed an hexagonal crystal growth form, as did those of the gut tissue and gut contents. The gut tissue had high levels of thermal hysteresis (approximately 2 degrees C) and the gut contents somewhat lower levels (approximately 0.6 degrees C). Recrystallization inhibition activity mirrored that of thermal hysteresis, with activity absent in the haemolymph or fat body cells but present in the gut tissues and contents. Activity was reduced by heating and was associated with a molecule >14kDa in size. These findings suggest an antifreeze protein is involved. In fed animals, ice nucleation is likely to start in the gut. Gut cells have a much greater resistance to freezing than do fat body or Malpighian tubule cells. The antifreeze protein may enable this tissue to survive freezing stress by inhibiting recrystallization. PMID:18955061

  7. Ultrastructural and Extracellular Protein Changes in Cell Suspension Cultures of Populus euphratica Associated with Low Temperature-induced Cold Acclimation

    Institute of Scientific and Technical Information of China (English)

    Dai Huanqin; Lu Cunfu; Zhang Hui; Zhang Xujia

    2003-01-01

    Populus euphratica Olive is the only tree species that can grow in the saline land and also survive cold winters in northwest China, and it plays a very important role in stabilizing the vulnerable ecosystem there. A cell suspension culture was initiated from callus derived from plantlets of Populus euphratica. Cold acclimation was induced (LT50 of-17.5 ℃) in cell suspension at 4-5 ℃ in the dark for 30 days and the freezing tolerance increased from LT50 of-12.5 ℃ in nonacclimated cells to LT50 of-17.5 ℃ in cold-acclimated cells. Microvacuolation, cytoplasmic augmentation and accumulation of starch granules were observed in cells that were cold-acclimated by exposure to low temperatures. Several qualitative and quantitative changes in proteins were noted during cold acclimation. Antibodies to carrot extracellular (apoplastic) 36 kD antifreeze protein did not cross react on immunoelectroblots with extracellular proteins in cell suspension culture medium of Populus euphratica, indicating no common epitopes in the carrot 36 kD antifreeze protein and P euphratica extracellular proteins. The relationship of these changes to cold acclimation in Populus euphratica cell cultures was discussed.

  8. A biological model for controlling interface growth and morphology.

    Energy Technology Data Exchange (ETDEWEB)

    Hoyt, Jeffrey John; Holm, Elizabeth Ann

    2004-01-01

    Biological systems create proteins that perform tasks more efficiently and precisely than conventional chemicals. For example, many plants and animals produce proteins to control the freezing of water. Biological antifreeze proteins (AFPs) inhibit the solidification process, even below the freezing point. These molecules bond to specific sites at the ice/water interface and are theorized to suppress solidification chemically or geometrically. In this project, we investigated the theoretical and experimental data on AFPs and performed analyses to understand the unique physics of AFPs. The experimental literature was analyzed to determine chemical mechanisms and effects of protein bonding at ice surfaces, specifically thermodynamic freezing point depression, suppression of ice nucleation, decrease in dendrite growth kinetics, solute drag on the moving solid/liquid interface, and stearic pinning of the ice interface. Stearic pinning was found to be the most likely candidate to explain experimental results, including freezing point depression, growth morphologies, and thermal hysteresis. A new stearic pinning model was developed and applied to AFPs, with excellent quantitative results. Understanding biological antifreeze mechanisms could enable important medical and engineering applications, but considerable future work will be necessary.

  9. 新技术在食品冷冻过程中的应用%Application of New Technologies in Frozen Food Processing

    Institute of Scientific and Technical Information of China (English)

    朱立贤; 罗欣

    2009-01-01

    文中对超声冷冻技术、高压冷冻技术、冰核活性细菌和冰核活性蛋白及抗冻蛋白在食品冷冻过程中的应用作一介绍.%The quality of frozen food relates to freezing processes, in which different methods have different freez-ing rate. Power ultrasound freezing is using ultrasound to assist food freezing by generate cavitations in the aqueous phase. High pressure method can greatly aid freezing process and improve product quality. The main advantage of high-pressure freezing is to form small and homogeneous ice crystals upon pressure release, and thus reduce the dam-age to the inner texture and structure of the food. The function of the antifreeze proteins is to lower the freezing tem-perature and suppress the growth of ice nuclei, thus inhibiting ice formation and altering the ice habit and growth rate.Ice nucleation active bacteria can reduce the degree of super cooling and catalyze ice formation. This paper overviews several freezing technologies such as ultrasonic freezing, high pressure freezing, and the methods of using antifreeze proteins and ice nucleus bacteria freezing proteins.

  10. Efficacy Study of Dolichos biflorus in the Management of Nephrotoxicity

    Institute of Scientific and Technical Information of China (English)

    Sarmistha Saha; Ramtej J Verma

    2012-01-01

    Objective: Ethylene glycol is widely used as a solvent and automobile antifreeze agent. Therefore, there have been a number of cases of human exposure from accidental or intentional ingestion of antifreeze, with the kidney being the most sensitive target organ. This study was designed to investigate the protective effect of seeds of Dolichos biflorus (Fabaceae), on ethylene glycol induced nephrotoxicity in adult female Wistar rats. Methods: The hydro-methanolic (30:70, v/v) extract of D. biflorus was orally administrated at doses of 150 and 300 mg/kg body weight/day along with ethylene glycol (0.75% v/v) for 28 days. The results were compared with a parallel study conducted with standard marketed drug cystone under identical dosage conditions. The ionic chemistry was measured in urine and serum. Statistical differences and linear regression analysis were performed using GraphPad prism 5 software. Results: Ethylene glycol induced a significant elevation in the creatinine, uric acid, urea levels in urine as well as in serum and urinary electrolytes (sodium and potassium) excretion levels. D. biflorus significantly (P<0.001) protected the elevated levels of urine and serum parameters. Moreover, D. biflorus shows higher renoprotective index than cystone at identical dose levels. Conclusions: These results provided an evidence of the significant protective effect of D. biflorus towards hyperuricemic and nephrotoxicity and thus can be used as potent dietary food.

  11. A novel psychrophilic Janthinobacterium lividum MMPP4 isolated from Manimahesh Lake of Chamba District of Himachal Pradesh, India

    Directory of Open Access Journals (Sweden)

    Ranjana Suman

    2015-04-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 We isolated psychrophilic bacterial strains from high altitude (elevation 13,390 ft Manimahesh Lake of Chamba District of Himachal Pradesh. Based on phenotypic characteristics and growth appearance at 4ºC, four bacterial isolates (MMPP2, MMPP4, MMPP5, and MMPP7 were selected and showed optimum growth at 20ºC and no growth was detected at 25ºC.  Qualitative assay showed that cell free medium of MMPP4 prevent inhibition of freezing (antifreeze activity as determined by freezing of cell free medium at -20ºC for seven days. Proteinase K treatment and heat inactivation at 80ºC for 6 h resulted in the loss of antifreeze activity, suggesting a proteinaceous nature of antifreeze activity. MMPP4 produces protease, phytase and lipase enzymes, but did not produce amylase. Moreover, cell free supernatant of MMPP4 showed proteinaceous type of antimicrobial activity against S. aureus as measured by agar well diffusion assay.  To identify the MMPP4 strain, 16s rDNA was amplified using 27F and 1492R standard primers and sequenced on both the strands. Nucleotide BLAST and phylogenetic analysis showed 99% identity to Janthinobacterium lividum strain and deposited in GenBank accession no. as KJ509870. The finding revealed a great potential of the Janthinobacterium lividum strain MMPP4 for biotechnological applications as a source of industrially important enzymes and antimicrobial compound.     /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New

  12. MANIFESTATION OF THE EFFECT OF CRYOSELECTION IN CARP OFFSPRINGS OBTAINED FROM DEFROSTED SPERM SUSPENSION WITH MODIFIED CRYOPROTECTIVE SOLUTIONS

    Directory of Open Access Journals (Sweden)

    V. Cherepnin

    2016-09-01

    Full Text Available Purpose. The purpose of these studies was to evaluate the effect of the cryoselection of carp sperm of multiple age groups depending on the quality of thawed sperm after modification of the composite cryoprotective medium, which was used for the dilution of native sperm before freezing. Methodology. Coenzyme B12 (cobamamide, blood plasma of Prussian carp (Carassius gibelio, which was subjected to natural cold-acclimation, and purified protein antifreeze tmAFP isolated from larval mealworm (Tenebrio molitor, which also was subjected to natural cold-acclimation, were sued as modifiers. Findings. The results of the study demonstrated that qualitative and quantitative characteristics of the defrosted sperm, results of the incubation, rearing of embryos and larvae of Nyvky scaled carp (NLC, as well as fish culture parameters of produced young-of-the-year depended from on the composition of cryoprotective medium. The best results were demonstrated for the experimental groups, obtained with the use of the cryoprotective solution supplemented with purified antifreeze protein tmAFP. The larvae obtained from the sperm cryopreserved with the addition of cryoprotective medium TmAFP had better resistance to dehydration, surpassing the experimental groups obtained from the modifiers of Prussian carp plasma and cobamamide. There is a consolidation in the action of the related extracellular cryoprotectors, which were isolated from the cold-resistant organisms. And carp produced with their used demonstrated better performance during their rearing. The fact can be established that the manifestation of cryoselective effect depends on the integrity of sperm hereditary material and does not depend on the effect of extremely low temperatures on the cell membranes. Originality. There were the first experiments, where Prussian carp plasma and antifreeze protein tmAFP were used as extracellular cryoprotectors. Practical value. The modifications of composite

  13. Temperatures and Heat Flows in a Soil Enclosing a Slinky Horizontal Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Pavel Neuberger

    2014-02-01

    Full Text Available Temperature changes and heat flows in soils that host “slinky”-type horizontal heat exchangers are complex, but need to be understood if robust quantification of the thermal energy available to a ground-source heat pump is to be achieved. Of particular interest is the capacity of the thermal energy content of the soil to regenerate when the heat exchangers are not operating. Analysis of specific heat flows and the specific thermal energy regime within the soil, including that captured by the heat-exchangers, has been characterised by meticulous measurements. These reveal that high concentrations of antifreeze mix in the heat-transfer fluid of the heat exchanger have an adverse impact on heat flows discharged into the soil.

  14. 长输管道低温施工的技术问题分析%Technical problems of long distance pipeline construction analysis at low temperature

    Institute of Scientific and Technical Information of China (English)

    张卫云

    2015-01-01

    这篇文章是关于降低温度的环境问题影响长输管道的施工的影响,提出了焊接、下沟、管沟爆破、防腐、回填、管沟开挖等施工技术的保障办法,列举了较低温度下的施工机械和施工人员的防冻保护事项。%This article is about the influence of the construction of long distance pipeline to reduce the temperature of the impact of environmental issues,the welding pipe ditch,ditch,blasting,anti-corrosion,back fill,pipe trench excavation construction technology security measures,lists the antifreeze protection issues of construction machinery and construction workers at lower temperature.

  15. Computer-assisted design of oil additives: hydrate and wax inhibitors

    Science.gov (United States)

    Duffy, D. M.; Moon, C.; Rodger, P. M.

    In this paper we present the results of a molecular simulation study of low dosage anti-freeze agents for two common problems that occur during oil and gas transport: gas hydrate crystallization and wax deposition. Direct molecular dynamics simulations are presented of the nucleation and growth of methane hydrate from a liquid water film, and of the suppression of this growth in the presence of a well-known kinetic inhibitor - polyvinylpyrrolidone. In the case of wax inhibition we present a simple model for predicting the activity of comb-like polymers, which is likely to be useful for identifying the most active inhibitor from within a given class. The method is applied to a set of random copolymers and shown to correlate well with experimental data.

  16. NVENTIONS IN THE NANOTECHNOLOGICAL AREA PROVIDE INCREASED RESISTANCE OF CONSTRUCTION MATERIALS AND PRODUCTS TO OPERATIONAL LOAD

    Directory of Open Access Journals (Sweden)

    VLASOV Vladimir Alexeevich

    2013-12-01

    Full Text Available The invention «Dispersion of Carbon Nanotubes (RU 2494961» can be used in production of modifying additives for construction materials. Dispersion of carbon nanotubes contains, mass %: carbon nanotubes 1–20; surface active agent – sodium chloride of sulfonated derived naphthalene 1–20; fumed silica 5–15; water – the rest. Dispersion can additionally contain ethylene glycol as antifreeze. Dispersion is steady in storage, it is soluble in water, provides increased strength of construction materials. Invention «Building Structures Reinforcement Composition (RU 2493337» can beused in construction to reinforce concrete, brick and masonry structures. Composition contains glass or basalt roving taken in quantity 90÷100 parts by weight, soaked in polymer binder based on epoxy taken in quantity 0,001÷1,5 parts by weight. This invention provides high resistance to operational load.

  17. Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia

    Science.gov (United States)

    1981-01-01

    A solar space and water heating system is described. The solar energy system consists of 2,520 sq. ft. of flat plate solar collectors and a 4,000 gallon solar storage tank. The transfer medium in the forced closed loop is a nontoxic antifreeze solution (50 percent water, 50 percent propylene glycol). The service hot water system consists of a preheat coil (60 ft. of 1 1/4 in copper tubing) located in the upper third of the solar storage tank and a recirculation loop between the preheat coil and the existing electric water heaters. The space heating system consists of two separate water to air heat exchangers located in the ducts of the existing space heating/cooling systems. The heating water is supplied from the solar storage tank. Extracts from site files, specification references for solar modifications to existing building heating and hot water systems, and installation, operation and maintenance instructions are included.

  18. Study on durability and the influenced factors of self-compacting concrete%自密实混凝土耐久性及影响因素研究

    Institute of Scientific and Technical Information of China (English)

    许悦; 郑庆康; 敬和平

    2011-01-01

    Introduced the anti-freeze, carbonation, anti-chloride ion penetration and corrosion resistance performance of serf-compacting concrete, discussed the influences of the chemical additive and mineral admixtures to self-compacting concrete durability, so as to lay the foundation for the engineering application of self-compacting concrete.%介绍了自密实混凝土抗冻、抗碳化、抗氯离子渗透和抗硫酸盐侵蚀性能,探讨了化学外加剂和矿物掺合料对自密实混凝土耐久性的影响,以期为自密实混凝土的工程应用奠定基础。

  19. A Study of the Energy Efficiency of Hadronic Reactors of Molecular Type

    CERN Document Server

    Aringazin, A K

    2001-01-01

    In this paper, we introduce an estimate of the "commercial efficiency" of Santilli's hadronic reactors of molecular type (Patented and International Patents Pending) which convert a liquid feedstock (such as automotive antifreeze and oil waste, city or farm liquid waste, crude oil, etc.) into the clean burning magnegas plus heat acquired by the liquid feedstock. The "commercial efficiency" is defined as the ratio between the total energy output (energy in magnegas plus heat) and the electric energy used for its production, while the "scientific efficiency" is the usual ratio between the total energy output and the total energy input (the sum of the electric energy plus the energy in the liquid feedstock as well as that in the carbon electrodes). A primary purpose of this paper is to show that conventional thermochemistry does indeed predict a commercial efficiency bigger than one, although their values is considerably smaller than the actual efficiency measured in the reactors, thus indicating the applicabili...

  20. Friction and Wear Modifiers Using Solvent Partitioning of Hydrophilic Surface-Interactive Chemicals Contained in Boundary Layer-Targeted Emulsions

    Science.gov (United States)

    Richmond, Robert Chaffee (Inventor); Schramm, Harry F., Jr. (Inventor); Defalco, Francis G. (Inventor)

    2016-01-01

    A wear and/or friction reducing additive for a lubricating fluid in which the additive is a combination of a moderately hydrophilic single-phase compound and an anti-wear and/or anti-friction aqueous salt solution. The aqueous salt solution produces a coating on boundary layer surfaces. The lubricating fluid can be an emulsion-free hydrophobic oil, hydraulic fluid, antifreeze, or water. Preferably, the moderately hydrophilic single-phase compound is sulfonated castor oil and the aqueous salt solution additionally contains boric acid and zinc oxide. The emulsions produced by the aqueous salt solutions, the moderately hydrophilic single-phase compounds, or the combination thereof provide targeted boundary layer organizers that significantly enhance the anti-wear and/or anti-friction properties of the base lubricant by decreasing wear and/or friction of sliding and/or rolling surfaces at boundary layers.

  1. 谈冬季施工混凝土配合比设计%Discussion on mix ratio design of winter construction concrete

    Institute of Scientific and Technical Information of China (English)

    王宏宁

    2012-01-01

    This paper made calculation and analysis on mix ratio test of winter construction concrete, and made thinking to cement, water-ce- ment ratio selection, additives, curing condition and discharging temperature and other problems encountered in this process, put forward the i- deas, so as to ensure the winter construction concrete has enough antifreeze.%对冬季施工混凝土配合比试配进行计算与分析,并对该过程中遇到的水泥、水灰比的选择、外加剂、养护条件和出料温度等问题进行思考,以确保冬季施工混凝土有足够的抗冻性。

  2. 基于混凝土养护温度过低的分析研究%Analysis and Research on Too Low Concrete Curing Temperature

    Institute of Scientific and Technical Information of China (English)

    段江涛; 李志鹏

    2014-01-01

    At present, concrete winter construction becomes more and more common, but due to part of management personnel has some errors for winter construction techniques and the application of antifreeze, engineering accidents continue to emerge. Based on the quality accident in a residential building of Zhengzhou caused by cold, this paper analyzes the reasons and introduces the preventive measures.%目前,混凝土冬期施工越来越普遍,但是由于部分管理人员对冬施技术及防冻剂的应用存在一些误区,致使工程事故不断出现。下面仅就郑州某住宅楼工程质量因受冻而引发的质量事故进行原因分析和预防措施介绍。

  3. Studies of molecular properties of polymeric materials: Aerospace environmental effects on three linear polymers

    Science.gov (United States)

    Harries, W. L.; Ries, H. R.; Bradbury, C. A.; Gray, S. L.; Collins, W. D.; Long, S. A. T.; Long, E. R., Jr.

    1985-01-01

    The development of crystal handling techniques for reflection infrared spectroscopy and methods for the fabrication and testing of tensile specimens are discussed. Data from mechanical, ac and dc electrical, and electron paramagnetic resonance studies conducted to determine the effects of 0.1-MeV and 1.0-MeV electron radiation on Mylar, Kapton, Ultem, and metal-doped Ultem are presented. Total doses ranging from 1 X 10 to the 8 rads to 1 X 10 to the 10 rads and dose rates from 5 X 10 to the 7 rads/hr to 1 X 10 to the 9 rads/hr were employed. The results of a study on the effects of aircraft service-environment fluids on Ultem are also reported. The weights and mechanical properties of Ultem were evaluated before and after exposure to water, JP4, Skydrol, an antifreeze, and a paint stripper.

  4. 汽车发动机冷却系统的腐蚀与防护%CORROSION AND PROTECTION OF COOLING SYSTEM OF AUTOMOTIVE ENGINE

    Institute of Scientific and Technical Information of China (English)

    刘丽明; 王晓波; 王萍; 张焕仁

    2001-01-01

    参照日本防冻液的金属腐蚀试验方法JIS-K-2234,对各种不同的复合型缓蚀剂配制的防冻液进行了金属腐蚀试验测试,并对测试结果进行了分析讨论,最后确定了对铸铁、钢、铜、铸铝、锡都具有较好缓蚀作用的复合型缓蚀剂的科学配制方法,利用美国ASTM方法对防冻液进行了性能测试。配制的防冻液可以有效地延长汽车发动机冷却系统的使用寿命,使汽车达到高性能化。%By reference to metal corrosion test methods JIS -K-2234 some,anti-freeze fluids which were made up of various compounded-typ e inhibitor were tested for metal corrosion.The results were discussed,the scientific methods of making up compounded-type inhibitor which can play better role of inhibitor for ordinary iron,steel,copper,ordinary aluminium、tin wer e determined at last.By the methods of ASTM the performance of anti-freeze flui d has been tested.The anti-freeze fluids which was so formed can prolong effe cti vly service life of cooling system of automotive engine,and can make automotive having high property.

  5. 砌块用轻集料混凝土的性能研究%Study the properties of lightweight aggregate for make the block

    Institute of Scientific and Technical Information of China (English)

    陈益兰; 潘荣伟; 唐国武; 徐伟

    2012-01-01

    利用多微孔轻集料、建筑固体废弃物作集料,水泥和粉煤灰、脱硫石膏、电石渣等工业废渣作复合胶凝材料制备轻集料混凝土,对其力学性能、抗冻和耐高温性能进行研究.实验结果表明:轻集料混凝土密度等级为1500 kg/m3时,强度等级达到LC20,抗冻标号均达到F15,符合非采暖地区抗冻要求;显示出良好的耐高温性能,在400℃时实验样品的抗压强度没有下降,甚至略高于标准养护条件下28 d抗压强度值.在此基础上制备了具有自保温功能的轻集料混凝土小型空心砌块,其体积密度为940 kg/m3,抗压强度为5.4 MPa,砌筑墙体传热系数为1.26 W/(m2·K).%In this paper, the multi-porous lightweight aggregate and construction of solid waste were used as aggregate, cement and fly ash,gypsum, calcium carbide slag and other industrial waste were used as composite cementitious material, to make lightweight aggregate concrete. And study its mechanical properties,its frost resistance and high temperature performance. The results show that the lightweight aggregate concrete's compressive strength level up to LC20,when the density level keep in 1500 kg/m3;the antifreeze experimental results show that the antifreeze label reach F15,in line with the non-heating area antifreeze requirements; The lightweight aggregate concrete shows good resistance to high temperature. The high temperature performance experimental results show that the compressive strength of lightweight aggregate concrete after high temperature of 400 ℃ is not drop, some of the samples is still higher than the 28 d compressive strength under the standard conditions of curing. On this basis, lightweight aggregate concrete small hollow block with insulation function is made,its density is 940 kg/m3, the compressive strength is 5.4 MPa,when laying into wall the heat transfer coefficient is 1.26 W/(m2·K).

  6. The Best Treatment Effects of Active Carbon on Low-alcohol Liquor of Different Alcoholicity%不同酒度低度白酒活性炭处理最佳效果

    Institute of Scientific and Technical Information of China (English)

    代汉聪; 张宿义; 谢明; 李云辉

    2012-01-01

    对不同酒度低度白酒活性炭除浊、香味损失及化学性能等指标进行了研究。结果表明,同一酒度白酒进行活性炭处理,随着活性炭用量的增加,酒中己酸乙酯、乳酸乙酯、乙酸乙酯、丁酸乙酯等色谱骨架成分及棕榈酸乙酯、亚油酸乙酯、油酸乙酯等高级脂肪酸乙酯的含量均有一定程度的降低;总酸、总酯也随着活性炭添加量的增加有一定程度减小,且酒质香浓感减弱,酒体抗冻能力增强。用同量活性炭对不同酒度白酒进行处理,酒度越高,其处理降度后的低度白酒微量香味成分越丰富,酒质香浓感越好,但酒体抗冻能力越弱。新处理工艺能够增加酒体香浓感,且大幅度提升酒体口感质量。%Active carbon was used for turbidity-removal of low-alcohol liquor of different alcoholicity,and the loss of liquor aroma and the change in its chemical indexes were studied.The results indicated that,for liquor of the same alcoholicity,with the increase of active carbon use level,the content of ethyl caproate,ethyl lactate,ethyl acetate,ethyl butyrate,palmitic acid ethyl ester,ethyl linoleate,ethyl oleate and other higher fatty ethyl esters reduced to some extent in the liquor,the content of total acids and total esters also decreased and liquor aroma weakened,however,liquor antifreeze capacity enhanced;for liquor of different alcoholicity but treated by the same use level of active carbon,the higher of liquor alcoholicity,the richer of trace flavoring components in treated liquor and the better of liquor quality and liquor aroma,however,the weaker of liquor antifreeze capacity.The new processing techniques could enhance the aroma of liquor body and greatly improve liquor taste and liquor quality.

  7. Development of a Directed Vat Set Starter of Lactic Acid Bacteria%直投式乳酸菌发酵剂的研制

    Institute of Scientific and Technical Information of China (English)

    方义川; 杨虹坤; 何谦; 韩笑; 刘秉杰; 李适云; 杨益衡; 胡文锋

    2012-01-01

    本研究旨在研制出一种菌活高、使用简单,无需复杂的无菌操作技术与设备的直投式乳酸菌发酵剂,可用于发酵乳、泡菜以及动物饲料发酵和生产.本发酵剂以嗜酸乳杆菌LHlF为菌种,实验过程优化番茄汁增菌培养基的配方,细胞数目达4.25×1010CFU/mL.最佳的抗冷冻保护剂的配方为:脱脂奶粉2.5%,甘油1%,葡萄糖2.5%,蔗糖1%,Vc2.5%.真空冷冻干燥的条件为4000 r/min,20min离心获得菌体后真空冷冻干燥6h.通过优化的直投式乳酸菌发酵剂的活菌数可以速到1.27× 1012CFU/g;于4℃存放三个月后,乳酸菌活菌数仍达到3× 1010 CFU/g.因此,经过优化乳酸菌发酵条件及保护剂配方,所得的冻干型直投式菌种可用于乳品及动物饲料的发酵.%A Directed Vat Set (DVS) of lactic acid bacteria (LAB) was developed for the fermentation and production of fermented soft drink and animal feed. Lactobacillus acidophilus LH1F was used as test strain. The cultural media for the L.acidophilus LH1F growth and the ingredients of anti-freeze protectants for lyophilization of LAB cells were optimized by orthogonal tests. The highest cell concentration of 4.25×1010 CFU/mL was found using tomato juice enrichment medium. The optimized anti-freeze protectants recipe contained skimmed milk powder 2.5%, glycerol 1%, glucose 2.5%, sucrose 1% and Vitamine C 2.5%. After 6 hours lyophilization, the number of viable LAB cells of DVS was about 1.27× 1012 CFU/g. The cell number still maintained 3×1010 CFU/g after three months preservation at 4 ℃.

  8. Geophysics and geochemistry intertwined: Modeling the internal evolution of Ceres, Pluto, and Charon

    Science.gov (United States)

    Neveu, Marc; Desch, Steven J.; Castillo-Rogez, Julie C.

    2015-11-01

    Liquid water likely shaped dwarf planet evolution: observations [1,2] and models [3-5] suggest aqueous alteration of silicates or volatiles accreted by these worlds. Driven by thermo-physical settings, aqueous alteration also feeds back on dwarf planet evolution in unconstrained ways. Can rocky dwarf planet cores crack, increasing the water-rock interface? Might radionuclides be leached into fluids, changing the distribution of this chief heat source? What is the fate of antifreezes, on which may hinge long-term liquid persistence? Is volcanism favored or impeded? What are predicted cryomagma compositions?We have modeled silicate core fracturing [6], geochemical equilibria between chondritic rock and aqueous fluids [7], and prerequisites for cryovolcanism [8]. These models, coupled to an evolution code [3], allow us to study geophysics/chemistry feedbacks inside dwarf planets.Ice-rock differentiation, even partial [9,10], yields a rocky, brittle core cracked by thermal stresses; liquid circulation through core cracks transports heat into the ice mantle, yielding runaway melting that quickly ceases once convection cools the mantle to its freezing point [6]. Hot fluids can leach radionuclides at high water:rock ratios (W:R); NH3 antifreeze can turn into NH4-minerals at low W:R [7]. Volatile (chiefly CO) exsolution enables explosive cryovolcanism [8]; this may explain Pluto’s young, CO-rich Tombaugh Regio.Applied to Ceres, such models are consistent with pre-Dawn and Dawn data [11] provided Ceres partially differentiated into a rocky core and muddy mantle [10]. They suggest Ceres’ hydrated surface [2] was emplaced during a 26Al-fueled active phase, and predict its bright spots result from cryovolcanic fluids squeezed by mantle refreezing and effusing through pre-existing subsurface cracks [11].[1] Cook et al. 2007 ApJ 663:1406[2] Milliken & Rivkin 2009 Nat Geosc 2:258[3] Desch et al. 2009 Icarus 202:694[4] Castillo-Rogez et al. 2010 Icarus 205:443[5] Robuchon

  9. Incorporation of Therapeutic Interventions in Physiologically Based Pharmacokinetic Modeling of Human Clinical Case Reports of Accidental or Intentional Overdosing with Ethylene Glycol

    Energy Technology Data Exchange (ETDEWEB)

    Corley, Rick A.; McMartin, K. E.

    2005-05-16

    Ethylene glycol is a high production volume chemical used in the manufacture of resins and fibers, antifreeze, deicing fluids, heat transfer and hydraulic fluids. Although occupational uses of ethylene glycol have not been associated with adverse effects, there are case reports where humans have either intentionally or accidentally ingested large quantities of ethylene glycol, primarily from antifreeze. The acute toxicity of ethylene glycol in humans and animals and can proceed through three stages, each associated with a different metabolite: central nervous system depression (ethylene glycol), cardiopulmonary effects associated with metabolic acidosis (glycolic acid) and ultimately renal toxicity (oxalic acid), depending upon the total amounts consumed and effectiveness of therapeutic interventions. A physiologically based pharmacokinetic (PBPK) model developed in a companion paper (Corley et al., 2004) was refined in this study to include clinically relevant treatment regimens for ethylene glycol poisoning such as hemodialysis or metabolic inhibition with either ethanol or fomepizole. Such modifications enabled the model to describe several human case reports which included analysis of ethylene glycol and/or glycolic acid. Such data and model simulations provide important confirmation that the PBPK model developed previously can adequately describe the pharmacokinetics of ethylene glycol in humans following low, occupational or environmentally relevant inhalation exposures, as well as massive oral doses even under conditions where treatments have been employed that markedly affect the disposition of ethylene glycol and glycolic acid. By integrating the case report data sets with controlled studies in this PBPK model, it was demonstrated that fomepizole, if administered early enough in a clinical situation, can be more effective than ethanol or hemodialysis in preventing the metabolism of ethylene glycol to more toxic metabolites. Hemodialysis remains an

  10. Annealing condition influences thermal hysteresis of fungal type ice-binding proteins.

    Science.gov (United States)

    Xiao, Nan; Hanada, Yuichi; Seki, Haruhiko; Kondo, Hidemasa; Tsuda, Sakae; Hoshino, Tamotsu

    2014-02-01

    The Antarctic sea ice diatom Navicular glaciei produced ice-binding protein (NagIBP) that is similar to the antifreeze protein (TisAFP) from snow mold Typhula ishikariensis. In the thermal hysteresis range of NagIBP, ice growth was completely inhibited. At the freezing point, the ice grew in a burst to 6 direction perdicular to the c-axis of ice crystal. This burst pattern is similar to TisAFP and other hyperactive AFPs. The thermal hysteresis of NagIBP and TisAFP could be increased by decreasing a cooling rate to allow more time for the proteins to bind ice. This suggests the possible second binding of proteins occurs on the ice surface, which might increase the hysteresises to a sufficient level to prevent freezing of the brine pockets which habitat of N. glaciei. The secondary ice binding was described as that after AFP molecules bind onto the flat ice plane irreversibly, which was based on adsorption-inhibition mechanism model at the ice-water interface, convex ice front was formed and overgrew during normal TH measurement (no annealing) until uncontrolled growth at the nonequilibrium freezing point. The results suggested that NagIBP is a hyperactive AFP that is expressed for freezing avoidance.

  11. Silica as a Matrix for Encapsulating Proteins: Surface Effects on Protein Structure Assessed by Circular Dichroism Spectroscopy

    Directory of Open Access Journals (Sweden)

    Genet H. Zemede

    2012-08-01

    Full Text Available The encapsulation of biomolecules in solid materials that retain the native properties of the molecule is a desired feature for the development of biosensors and biocatalysts. In the current study, protein entrapment in silica-based materials is explored using the sol-gel technique. This work surveys the effects of silica confinement on the structure of several model polypeptides, including apomyoglobin, copper-zinc superoxide dismutase, polyglutamine, polylysine, and type I antifreeze protein. Changes in the secondary structure of each protein following encapsulation are monitored by circular dichroism spectroscopy. In many cases, silica confinement reduces the fraction of properly-folded protein relative to solution, but addition of a secondary solute or modification of the silica surface leads to an increase in structure. Refinement of the glass surface by addition of a monosubstituted alkoxysilane during sol-gel processing is shown to be a valuable tool for testing the effects of surface chemistry on protein structure. Because silica entrapment prevents protein aggregation by isolating individual protein molecules in the pores of the glass material, one may monitor aggregation-prone polypeptides under solvent conditions that are prohibited in solution, as demonstrated with polyglutamine and a disease-related variant of superoxide dismutase.

  12. Inhibition of hydrate formation by kinetic inhibitors. Literature study; Inhibierung von Erdgashydraten durch kinetische Inhibitoren. Literaturstudie

    Energy Technology Data Exchange (ETDEWEB)

    Eberhardt, E.; Meyn, V.; Rahimian, I. [Institut fuer Erdoel- und Erdgasforschung, Clausthal-Zellerfeld (Germany)

    2000-04-01

    The aim of this study was to represent the state-of-the art of the inhibition of gas hydrates. Corresponding to recent publications the kinetic inhibition was considered in particular. Special inhibitors were validated using a set of criteria derived from different experimental test methods. Best results were obtained by the application of terpolymer VC-713 especially in relation to nucleation and crystal growth, followed by PVCap (polyvinylcaprolactame) and THI (threshold hydrate inhibitor), the chemical structure of which is derived from the antifreeze glycopeptids of antarcitc winter flounder. (orig.) [German] Die vorliegende Literaturstudie gibt den derzeitigen Stand der Kenntnis zur Inhibierung von Gashydraten wieder. Entsprechend der neueren Literatur wird insbesondere auf die kinetische Inhibierung eingegangen. Zur Beurteilung der verschiedenen Inhibitoren werden Bewertungskriterien zur Validierung der mit unterschiedlichen Untersuchungsmethoden erzielten experimentellen Ergebnisse angegeben. Anhand dieser Vorgehensweise zeigte sich, dass mit dem Terpolymer VC-713 die besten Ergebnisse, insbesondere im Hinblick auf Keimbildung und Wachstum, erzielt werden konnten. Sehr gute Ergebnisse wurden auch mit dem Polyvinylcaprolactam (PVCap) und den aus den Antigefrierpeptiden der antarktischen Winterflunder abgeleiteten Threshold Hydrate Inhibitoren (THI) erhalten. (orig.)

  13. Detection of ethylene glycol - toward W51/e2 and G34.3+0.02

    Science.gov (United States)

    Lykke, Julie M.; Favre, Cécile

    2014-07-01

    Ethylene glycol (HOCH2CH2OH), also commenly known as antifreeze, is the reduced alcohol version of glycolaldehyde (CH2OHCHO). Glycoladehyde - the simplest possible aldehyde sugar (Marstokk and Møllendal 1973) - is the first intermediate step in the path toward forming more complex and biologically relevant molecules through the the formose reaction, which begins with formaldehyde (H2CO) and ends with the formation of sugars and ultimately ribose, the backbone of RNA (e.g., Larralde et al. 1995). The presence of glycolaldehyde is therefore an important indication that processes leading to biologically relevant molecules are taking place. It is however, still unclear as to how glycolaldehyde and ethylene glycol are formed in the ISM. It has been proposed that they share a common formation pathway through UV-irradiation of methanol (CH3OH) ices mixed with CO (Öberg et al. 2009). So far, ethylene glycol, in its lower energy con-former (g’Ga(CH2OH)2), has been detected toward SgrB2 (N) by Hollis et al. (2002), tentatively toward IRAS 16293-2422 (Jørgensen et al. 2012) and marginally by Kalenskii and Johansson (2010) toward W51 e1/e2. Here we present a firm detection of ethylene glycol toward W51/e2 as well as a first detection toward G34.3+0.02 at 1mm and 3mm using the IRAM 30m telescope.

  14. On the Correlation between Air Content and Air Bubble Parameters Frost Resistance Performance of High Fly Ash Content Concrete%关于大掺量粉煤灰混凝土含气量、气泡参数表征抗冻能力相关性的探讨

    Institute of Scientific and Technical Information of China (English)

    艾红梅; 戴碧琳; 郭建华; 杨晨光

    2015-01-01

    鉴于冻融作用对大掺量粉煤灰混凝土( High Fly ash Content Concrete,HFCC)造成的破坏较为严重,对国内外的研究情况进行了分析,总结了现阶段大掺量粉煤灰混凝土抗冻性能的研究进展。主要对混凝土拌合物含气量和硬化混凝土气泡参数表征HFCC抗冻性的科学性和可行性进行了分析,并且对二者的相关性进行探讨。%Given the freeze-thaw effect on high fly ash content concrete ( HFCC ) is relatively serious,the paper analyzes the domestic and foreign research and summarizes the present research progress of antifreeze performance of concrete with high volume of fly ash. This paper mainly analyzes the science and feasibility of concrete mixture air content and hardened concrete bubble parameters HFCC frost resistance and explores the correlation between the two.

  15. [Strategies and mechanisms of soil springtails in adapting lower temperature environment: research progress].

    Science.gov (United States)

    Liu, Jing; Wang, Yun-Biao; Wu, Dong-Hui

    2012-12-01

    Low temperature and drought are the main environmental factors threatening the animals living in arctic area and cold temperate regions. To adapt the severe environment, the animals should adopt appropriate strategies. As a group of arthopods with freeze-avoiding strategy, soil springtails have the similar ecological mechanisms and modes of cold resistance/tolerance as insects, manifesting in the cold acclimation and drought tolerance to decrease the damage of ice crystal formation. During cold acclimation, there are a rapid increase of glycerol, a rapid decrease of fucose and glucose, and the production of anti-freeze proteins (AFP) , and exists the inter-transformation of different kinds of lipids to improve the flow of cell membrane to protect the cell from low temperature injury. In addition, soil springtails have their own specific modes and mechanisms to tolerate low temperature stress, mainly the vertical migration under the protection of snow cover and the excretion of ice nucleator from haemolymph, illustrating that it's of significance to research the cryobiology of soil springtails. This paper summarized the modes and mechanisms of soil springtails in tolerating low temperature environment, reviewed the research progress on the eco-physiology of the springtails, discussed the existing problems of the researches on the low temperature tolerance of the springtails, and prospected the research directions of the springtails low temperature ecology under the background of global change. PMID:23479899

  16. Elevated CO{sub 2} and development of frost hardiness in Norway spruce (picea abies (L.) Karst.); Oekt CO{sub 2} og utvikling av frostherdighet i gran

    Energy Technology Data Exchange (ETDEWEB)

    Dalen, Lars Sandved

    1998-09-01

    This thesis discusses controlled laboratory experiments carried out to study the effects of CO{sub 2} pollution on Norwegian spruce. It was found that elevated CO{sub 2} increased height growth and biomass production. It slightly increased frost hardiness, but only at high nitrogen values. There was no evidence of adverse effects of elevated CO{sub 2} on the phenology of bud set and the development of frost hardiness. Although not statistically significant, there seemed to be a consistently higher concentration of soluble carbohydrates in one-season-old Norway spruce seedlings treated with elevated CO{sub 2}. This was not found in three-year-old seedlings grown in open top chambers, possibly indicating a down-regulation of photosynthesis or a transition from free to predetermined growth, and change in allocation of photosynthates with age. Treatment with high or low concentrations of CO{sub 2} and nitrogen fertilizer did not affect apoplastic chitinolytic activity during cold acclimation, nor were there any effects on antifreeze activity in these apoplastic extracts from cold acclimated needles. 149 refs., 21 figs., 8 tabs.

  17. Discovery of a Homolog of Siderophilin in a Plant

    Institute of Scientific and Technical Information of China (English)

    Yun-Biao FEI; Peng-Xiu CAO; Su-Qin GAO; Ling-Bo WEI; Bin WANG

    2005-01-01

    Members belonging to the siderophilin family are iron-binding and iron-transporting proteins,which includes transferrin and lactoferrin. They have only been found in animals previously. If siderophilin could be found in and isolated from a plant, its production and subsequent extensive application could be increased. The present study is the first to report the discovery of a homolog of siderophilin in a plant. In order to purify antifreeze proteins from Ammopiptanthus mongolicus (Maxim.) Cheng f., the authors processed the proteins from the leaves using techniques such as column chromatography using DEAE-Cellulose-52, gel filtration via Sephacryl S-100 HR medium, hydrophobic interaction chromatography, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Mass spectroscopy was performed on the three proteins purified and the sequence of one of the proteins (containing 32 amino acids) was found to have 97%homology with the corresponding part of one type of human lactoferrin. Moreover, one of the two peptides belongs to an iron-binding domain. So, it is possible that siderophilin also exists in plants and plays a role as an antibacterial and antifungal, among other actions.

  18. Cold tolerance of the Antarctic nematodes Plectus murrayi and Scottnema lindsayae.

    Science.gov (United States)

    Wharton, David A; Raymond, Mélianie R

    2015-04-01

    The cold tolerance of the Antarctic nematodes Scottnema lindsayae and Plectus murrayi was determined using material freshly isolated from the field. Both species could survive low temperatures but the survival of S. lindsayae was greater than that of P. murrayi. Field soil temperatures in late spring-early summer indicated a minimum temperature of -19.5 °C and a maximum cooling rate of 0.71 °C min(-1). In P. murrayi grown in culture, there was no significant effect of acclimation, nor of the two culture media used, on survival after freezing but survival was greater if freezing was seeded at -1 °C than at lower temperatures. The freezing survival ability of P. murrayi is much less than that of Panagrolaimus davidi CB1, another Antarctic nematode. Cryomicroscopy indicates that P. murrayi can survive low temperatures by either cryoprotective dehydration or freezing tolerance, but that freezing tolerance is the dominant strategy. Measurable thermal hysteresis was detected only in highly concentrated extracts of the nematodes, indicating the presence of an antifreeze protein, but at the concentrations likely to be found in vivo, the major function of the ice active protein involved is probably recrystallization inhibition.

  19. Toxic optic neuropathy: An unusual cause

    Directory of Open Access Journals (Sweden)

    Hema L Ramkumar

    2014-01-01

    Full Text Available A 60-year-old woman with a history of chronic alcoholism and tobacco use presented with the complaint of a painless decrease in vision in both eyes. She lost vision first in the left eye then in the right eye. She admitted consuming at least one 16 ounce bottle of over the counter mouthwash daily and denied consumption of any other alcohols, methanol, or antifreeze. She stated that her vision had been continuing to deteriorate in both eyes. Her best-corrected visual acuity was 4/200 in each eye. Color vision was nil in each eye. Her pupils were sluggish bilaterally, and her optic discs were flat and hyperemic with peripapillary hemorrhages. Her visual fields revealed central scotomas bilaterally. The magnetic resonance imaging of the brain and lumbar puncture were within normal limits. Antinuclear antibody, human leukocyte antigen-B27 genotyping, and B12 were normal; serum thiamine was low. While continuing to ingest mouthwash, her vision decreased to count fingers at 2 feet, and maculopapillary bundle pallor developed. She was started on folate and thiamine supplementation. Once she discontinued mouthwash, her vision improved to 20/400 bilaterally, and her central scotomas improved. This case demonstrates an alcohol-induced toxic optic neuropathy from mouthwash ingestion with some visual recovery after discontinuation of the offending agent.

  20. Durham Nursing Home solar project: a case study

    Energy Technology Data Exchange (ETDEWEB)

    Swartman, R.K.; Ali, T. [Solcan Ltd., London, ON (Canada)

    2004-08-01

    Based on an earlier report indicating that an optimal match for solar energy applications is to preheat hot water used in nursing homes, this paper discusses the construction of a solar water pre-heating system at the Rockwood Terrace Nursing Home in Durham, Ontario. Performance of the system, costs and financial viability are predicted with the use of the RETScreen project management tool. In addition, system requirements and load and energy requirements are also taken into consideration with this tool, thereby ensuring the unique nature of each project. Thirty solar collectors were mounted on steel racks 3 stories above the mechanical room. A heat exchanger, heated by antifreeze, circulates to and from the solar collectors. Potable water is circulated from hot water storage tanks to the heat exchanger. Solar pre-heated water is then piped into a hot water storage tank, with a gas fired water heater heating potable hot water in a recirculation loop. The paper concludes that both Watsun 13.2 and RETScreen are both good predictive tools, having only exceeded actual measured performances of the system and its energy savings by 8 and 9 per cent respectively. 4 refs., 4 figs.

  1. Hydrogeology along the southern boundary of the Hanford Site between the Yakima and Columbia Rivers, Washington

    International Nuclear Information System (INIS)

    US Department of Energy (DOE) operations at the Hanford Site, located in southeastern Washington, have generated large volumes of hazardous and radioactive wastes since 1944. Some of the hazardous wastes were discharged to the ground in the 1100 and 3000 Areas, near the city of Richland. The specific waste types and quantities are unknown; however, they probably include battery acid, antifreeze, hydraulic fluids, waste oils, solvents, degreasers, paints, and paint thinners. Between the Yakima and Columbia rivers in support of future hazardous waste site investigations and ground-water and land-use management. The specific objectives were to collect and review existing hydrogeologic data for the study area and establish a water-level monitoring network; describe the regional and study area hydrogeology; develop a hydrogeologic conceptual model of the unconfined ground-water flow system beneath the study area, based on available data; describe the flow characteristics of the unconfined aquifer based on the spatial and temporal distribution of hydraulic head within the aquifer; use the results of this study to delineate additional data needs in support of future Remedial Investigation/Feasibility Studies (RI/FS), Fate and Transport modeling, Baseline Risk Assessments (BRA), and ground-water and land-use management

  2. The search for green inhibitors : perturbing hydrate growth with bugs

    Energy Technology Data Exchange (ETDEWEB)

    Huva, E.; Gordienko, R. [Queen' s Univ., Kingston, ON (Canada). Dept. of Biology; Ripmeester, J.; Zeng, H. [Queen' s Univ., Kingston, ON (Canada). Dept. of Biology]|[National Research Council of Canada, Ottawa, ON (Canada). Steacie Inst. for Molecular Sciences; Walker, V.K. [Queen' s Univ., Kingston, ON (Canada). Dept. of Biology]|[Queen' s Univ., Kingston, ON (Canada). Dept. of Microbiology and Immunology

    2008-07-01

    The ability of some organisms, such as insects and microbes, to survive low temperatures can be attributed to the production of either ice nucleating proteins (INPs) or antifreeze proteins (AFPs). INPs can direct crystal growth by inducing rapid ice formation. AFPs adsorb to ice embryos and decrease the temperature at which the ice grows. Certain AFPs can also inhibit the crystallization of clathrate hydrates and eliminate more rapid recrystallization or memory effect. This paper presented a study that involved the examination of bacterial species with ice-associating properties for their effect on tetrahydrofuran (THF) hydrate crystallization. As part of the study, THF hydrate formation was inhibited in the presence of cultures containing the ice-associating bacterium chryseobacterium C14. The paper discussed the methods used for the study, including hydrate formation and reformation in the presence of ice-associating bacteria and the development of a clathrate hydrate affinity purification technique. A 40 per cent reduction in crystallization was observed, indicating their potential as a commercial green inhibitor for hydrates. In addition, there was no elimination of memory effect, and little supporting evidence was seen for nucleation inhibition by any of the bacteria. 17 refs., 1 tab., 3 figs.

  3. Ice Nucleation by Alcohols Arranged in Monolayers at the Surface of Water Drops

    Science.gov (United States)

    Gavish, Michal; Popovitz-Biro, Ronit; Lahav, Meir; Leiserowitz, Leslie

    1990-11-01

    Monolayers of aliphatic long-chain alcohols induced nucleation of ice at temperatures approaching 0^circC, in contrast with water-soluble alcohols, which are effective antifreeze agents. The corresponding fatty acids, or alcohols with bulky hydrophobic groups, induce freezing at temperatures as much as 12^circC lower. The freezing point induced by the amphiphilic alcohols was sensitive not only to surface area per molecule but, for the aliphatic series (C_nH2n + 1OH), to chain length and parity. The freezing point for chains with n odd reached an asymptotic temperature of 0^circC for an upper value of n = 31; for n even the freezing point reached a plateau of -8^circC for n in the upper range of 22 to 30. The higher freezing point induced by the aliphatic alcohols is due to formation of ordered clusters in the uncompressed state as detected by grazing incidence synchrotron x-ray diffraction measurements. The diffraction data indicate a close lattice match with the ab layer of hexagonal ice.

  4. Ice slurry accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, K.G.; Kauffeld, M.

    1998-06-01

    More and more refrigeration systems are designed with secondary loops, thus reducing the refrigerant charge of the primary refrigeration plant. In order not to increase energy consumption by introducing a secondary refrigerant, alternatives to the well established single phase coolants (brines) and different concepts of the cooling plant have to be evaluated. Combining the use of ice-slurry - mixture of water, a freezing point depressing agent (antifreeze) and ice particles - as melting secondary refrigerant and the use of a cool storage makes it possible to build plants with secondary loops without increasing the energy consumption and investment. At the same time the operating costs can be kept at a lower level. The accumulation of ice-slurry is compared with other and more traditional storage systems. The method is evaluated and the potential in different applications is estimated. Aspects of practically use of ice-slurry has been examined in the laboratory at the Danish Technological Institute (DTI). This paper will include the final conclusions from this work concerning tank construction, agitator system, inlet, outlet and control. The work at DTI indicates that in some applications systems with ice-slurry and accumulation tanks have a great future. These applications are described by a varying load profile and a process temperature suiting the temperature of ice-slurry (-3 - -8/deg. C). (au)

  5. Effects of the Lithologic Character of Manufactured Sand on Properties of Concrete

    Institute of Scientific and Technical Information of China (English)

    WANG Jiliang; YANG Zhifeng; LIU Yihan

    2014-01-01

    Six representative parent rocks of sand, including limestone, quartzite, gneisses, granite, Basalt and Marble were selected to conduct a systematical research on the effects of various lithologies of manufactured sand on the workability, mechanism properties, volume stability and durability of manufactured-sand concrete. The experimental results show that the strength of manufactured-sand concrete is slightly higher than that of natural-sand concrete. Furthermore, substituting 15%cement of the concrete mixture with equal quantity of the six different lithology stone powder respectively, the data indicated that they can improve the concrete’s workability, postpone the plastic cracking time, enhance the anti-cracking grade, and have no obvious effect on the properties of antifreeze and sulfate attack resistance but reduce the capability to resist chloride ion penetration. Moreover, the differences in concrete’s workability, mechanism properties, volume stability and durability caused by various lithologies of manufactured sand and stone powder were not significant and the influence of lithology variety on the macro properties of concrete could be neglected eventually.

  6. Carbohydrate-Based Ice Recrystallization Inhibitors Increase Infectivity and Thermostability of Viral Vectors

    Science.gov (United States)

    Ghobadloo, Shahrokh M.; Balcerzak, Anna K.; Gargaun, Ana; Muharemagic, Darija; Mironov, Gleb G.; Capicciotti, Chantelle J.; Briard, Jennie G.; Ben, Robert N.; Berezovski, Maxim V.

    2014-07-01

    The inability of vaccines to retain sufficient thermostability has been an obstacle to global vaccination programs. To address this major limitation, we utilized carbohydrate-based ice recrystallization inhibitors (IRIs) to eliminate the cold chain and stabilize the potency of Vaccinia virus (VV), Vesicular Stomatitis virus (VSV) and Herpes virus-1 (HSV-1). The impact of these IRIs was tested on the potency of the viral vectors using a plaque forming unit assay following room temperature storage, cryopreservation with successive freeze-thaw cycles and lyophilization. Viral potency after storage with all three conditions demonstrated that N-octyl-gluconamide (NOGlc) recovered the infectivity of shelf stored VV, 5.6 Log10 PFU mL-1 during 40 days, and HSV-1, 2.7 Log10 PFU mL-1 during 9 days. Carbon-linked antifreeze glycoprotein analogue ornithine-glycine-glycine-galactose (OGG-Gal) increases the recovery of VV and VSV more than 1 Log10 PFU mL-1 after 10 freeze-thaw cycles. In VSV, cryostorage with OGG-Gal maintains high infectivity and reduces temperature-induced aggregation of viral particles by 2 times that of the control. In total, OGG-Gal and NOGlc preserve virus potency during cryostorage. Remarkably, NOGlc has potential to eliminate the cold chain and permit room temperature storage of viral vectors.

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

    Science.gov (United States)

    Costanzo, J P; Lee, R E; DeVries, A L; Wang, T; Layne, J R

    1995-03-01

    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 ice within body fluids. Conversely, freeze tolerance is an adaptation for the survival of tissue freezing under ecologically relevant thermal and temporal conditions that is conferred by the biosynthesis of permeating carbohydrate cryoprotectants and an extensive dehydration of tissues and organs. Such cryoprotective responses, invoked by the onset of freezing, mitigate the osmotic stress associated with freeze-concentration of cytoplasm, attendant metabolic perturbations, and physical damage. Cryomedical research has historically relied on mammalian models for experimentation even though endotherms do not naturally experience subfreezing temperatures. Some vertebrate ectotherms have "solved" not only the problem of freezing individual tissues and organs, but also that of simultaneously freezing all organ systems. An emerging paradigm in cryomedicine is the application of principles governing natural cold hardiness to the development of protocols for the cryopreservation of mammalian tissues and organs. PMID:7896003

  8. Streamlined approach for environmental restoration work plan for Corrective Action Unit 126: Closure of aboveground storage tanks, Nevada Test Site, Nevada. Revision 1

    International Nuclear Information System (INIS)

    This plan addresses the closure of several aboveground storage tanks in Area 25 of the Nevada Test Site. The unit is currently identified as Corrective Action Unit 126 in the Federal Facility Agreement and Consent Order and is listed as having six Corrective Action Sites. This plan addresses the Streamlined Approach for Environmental Restoration closure for five of the six sites. Four of the CASs are located at the Engine Test Stand complex and one is located in the Central Support Area. The sites consist of aboveground tanks, two of which were used to store diesel fuel and one stored Nalcool (an antifreeze mixture). The remaining tanks were used as part of a water demineralization process and stored either sulfuric acid or sodium hydroxide, and one was used as a charcoal adsorption furnace. Closure will be completed by removal of the associated piping, tank supports and tanks using a front end loader, backhoe, and/or crane. When possible, the tanks will be salvaged as scrap metal. The piping that is not removed will be sealed using a cement grout

  9. Ice nucleation of an insect lipoprotein ice nucleator (LPIN) correlates with retardation of the hydrogen bond dynamics at the myo-inositol ring.

    Science.gov (United States)

    Bäumer, Alexander; Duman, John G; Havenith, Martina

    2016-07-28

    Remarkably little is known about the mechanism of action of ice nucleation proteins (INPs), although their ability to trigger ice nucleation could be used in a broad variety of applications. We present CD measurements of an insect lipoprotein ice nucleator (LPIN) which show that the lipoproteins consist of a high amount of β-structures (35%). Terahertz absorption spectroscopy is used to probe the influence of the LPIN on the H-bond network dynamics. We observe a small, but significant THz excess, as an indication of an influence on the H-bond network dynamics. When adding the ice nucleation inhibitor sodium borate, this effect is considerably reduced, similar to that observed before for antifreeze glycoproteins (AFGPs). We propose that myo-inositol, the functional group of phosphatidylinositols, is crucial for the observed change of the H-bond network dynamics of hydration water. This hypothesis is confirmed by additional THz experiments which revealed that the influence of myo-inositol on the hydrogen bond network can be blocked by sodium borate, similar to the case of LPINs. Interestingly, we find a less significant effect when myo-inositol is replaced for chiro- and allo-inositol which underlines the importance of the exact positioning of the OH groups for the interaction with the H-bond network. We propose that a local ordering of water molecules is supporting ice nucleation activity for the LPIN in a similar way to that found for AFP activity in the case of hyperactive insect AFPs. PMID:27373225

  10. Pattern of CsICE1 expression under cold or drought treatment and functional verification through analysis of transgenic Arabidopsis.

    Science.gov (United States)

    Ding, Z T; Li, C; Shi, H; Wang, H; Wang, Y

    2015-01-01

    CsICE1 is thought to be involved in hardiness resistance of tea plants. Using seedling cuttings of biennial Wuniuzao in this study, the pattern of CsICE1 expression under cold temperature (4°, -5°C), drought [20% polyethylene glycol 6000 (PEG-6000)], and plant hormone [200 mg/L abscisic acid (ABA), 1 mg/L brassinolide (BR)] treatment was studied by real-time quantitative PCR. Additionally, stress resistance, such as the freezing resistance of CsICE1, was studied using Arabidopsis lines transformed with sense or anti-sense CsICE1 via Agrobacterium tumefaciens infection. Our results showed that CsICE1 mRNA could be induced under -5°C, PEG, ABA, or BR treatment, although the pattern of expression differed for all treatments. Compared to wild type (WT) and anti-sense ICE1 transgenic lines, sense lines displayed higher relative germination rates under salt and drought stress. After freezing treatment, the sense transgenic lines over-expressing CsICE1 showed a higher survival rate, increased levels of proline, and decreased levels of malonaldehyde. Conversely, compared with WT, anti-sense ICE1 transgenic lines had lower proline levels and higher malonaldehyde levels under freezing conditions. Our study indicates that CsICE1 is an important anti-freezing gene and that over-expression of CsICE1 can improve cold resistance and enhance salt and drought tolerance of transgenic lines. PMID:26400357

  11. Biological Removal of Propylene Glycol from Wastewater and its Degradation in Soil by the Activated Sludge Consortia

    Directory of Open Access Journals (Sweden)

    G.R Moussavi

    2009-07-01

    Full Text Available "n "nBackground and Objectives : Propylene glycol is the main compound of anti-freezing chemicals. A significant amount of propylene glycol is released to the environment after application and contaminates the soil. The main objective of this study was to determine the biological removal of propylene glycol from wastewater and its degradation in soil by the isolated bacteria from activated sludge process."nMaterials and Methods: In the present study, the sludge taken from the return flow in a local activated sludge treatment system was used as the initial seed. The performance of the bioreactor in treating the wastewater was evaluated at four different retention times of 18, 12, 6 and 4 h all with the inlet COD concentration of 1000 mg/L. This phase lasted around 4 months. Then, a part of the adapted microorganisms were transported from the bioreactor to the soil which was synthetically contaminated to the propylene glycol."nResults: The average of propylene glycol removal efficiency from the wastewater in detention times of 18, 12, 8 and 4 h in steady state conditions was 98.6%, 97.1%, 86.4% and 62.2% respectively. Also, the maximum degradation in soil was found to be 97.8%."nConclusion: According to the results obtained from this study, it appears that propylene glycol is inherently well biodegradable and can be biodegraded in liquid phase and soil after a short period of adaptation.

  12. 哺乳仔猪培育技术在规模猪场的应用实践%Suckling  Piglet  Breeding  Technology  Application  in  Scale  Pig  Farm

    Institute of Scientific and Technical Information of China (English)

    马永兰; 苏世文

    2012-01-01

      哺乳仔猪培育是养猪生产中的关键技术环节,它关系到以后的育肥效果。从多年的规模猪场生产实践摸索、总结出在规模猪场搞好哺乳仔猪培育应从初生仔猪出生前的的准备、初生仔猪的辅助接产、给初生仔猪及时吃足初乳、调节固定好奶头、保温防冻、防压、寄养调剂、补铁、诱食与补料、仔猪黄白痢防治、仔猪去势和预防接种等的12个技术环节采取措施。%  Suckling pig cultivation is the key technology in pig production, its relation to subsequent fattening effect. From the years of scale pig production practice, summed up in scale pig farm to breed from suckling piglets piglets born before the preparation of piglets, auxiliary production, time for adequate colostrum to newborn piglets, adjusted and fixed nipple, good insulation antifreeze, pressure prevention, foster care transfers, iron supplementation, and feeding attractant yellow and white scour of piglets, piglets, prevention of castration, vaccination of twelve technical links.

  13. Corrosion problems with aqueous coolants, final report

    Energy Technology Data Exchange (ETDEWEB)

    Diegle, R B; Beavers, J A; Clifford, J E

    1980-04-11

    The results of a one year program to characterize corrosion of solar collector alloys in aqueous heat-transfer media are summarized. The program involved a literature review and a laboratory investigation of corrosion in uninhibited solutions. It consisted of three separate tasks, as follows: review of the state-of-the-art of solar collector corrosion processes; study of corrosion in multimetallic systems; and determination of interaction between different waters and chemical antifreeze additives. Task 1 involved a comprehensive review of published literature concerning corrosion under solar collector operating conditions. The reivew also incorporated data from related technologies, specifically, from research performed on automotive cooling systems, cooling towers, and heat exchangers. Task 2 consisted of determining the corrosion behavior of candidate alloys of construction for solar collectors in different types of aqueous coolants containing various concentrations of corrosive ionic species. Task 3 involved measuring the degradation rates of glycol-based heat-transfer media, and also evaluating the effects of degradation on the corrosion behavior of metallic collector materials.

  14. Structure and Combustion of Magnegases

    CERN Document Server

    Santilli, R M

    2001-01-01

    In this paper, we study the structure and combustion of magnegases$^{TM}$ (Patented and International Patents Pending), new clean fuels developed by one of us (R.M.S.) [1], which are produced as byproducts of recycling nonradioactive liquid feedstock such as antifreeze waste, engine oil waste, town sewage, crude oil, etc., and generally vary with the liquid used for their production. A new technology, called PlasmaArcFlow\\tm, flows the waste through a submerged electric arc between conventional electrodes. The arc decomposes the liquid molecules into their atomic constituents, and forms a plasma in the immediate vicinity of the electrodes at about 10,000$^o$ F. The technology then moves the plasma away from the electrodes, and controls its recombination into environmentally acceptable fuels. The new fuels possess a ew chemical structure first identified by one of us (R.M.S.), which is characterized by clusters of ordinary molecules and atoms under a new bond of electromagnetic nature. These clusters constitut...

  15. 冷却塔防冻设计%Frost prevention design for cooling tower

    Institute of Scientific and Technical Information of China (English)

    杨文涛; 易钏

    2014-01-01

    针对冬季北方寒冷地区的冷却塔运行情况,对其产生冰冻的现象和原因进行了分析。从冷却塔产生冰冻现象的各个环节入手,逐一提出了行之有效的解决措施。同时介绍了大型钢混结构机力通风逆流式冷却塔的防冻技术和冬季运行技巧。%In this paper the frost phenomena and resean of the cooling tower are analyzed according to its winter operation in the northern cold region. The effective technique is proposed one by one on basis of the ev-ery segment of its frost penomena. At the same time the anti-freezing technology and the winter operation tech-nique for the large reinforced concrete structure power ventilation counter-flow cooling tower is introduced.

  16. Sorbitol as an arrester of embryonic development in diapausing eggs of the silkworm, Bombyx mori.

    Science.gov (United States)

    Horie; Kanda; Mochida

    2000-06-01

    Recently, it was confirmed that embryos derived from diapausing eggs of the silkworm, Bombyx mori, begin their development and reach larval maturity on mulberry leaves, when the naked eggs are cultured in vitro. In this study, we found that the method of embryo culture is useful for determining the physiological regulation of diapause. We show that the development of embryos derived from diapausing eggs was strongly inhibited by the addition of either sorbitol or trehalose to the culture medium. Furthermore, this inhibitory effect disappeared when the embryos were cultured in a control medium which did not contain either sorbitol or trehalose, indicating that the inhibitory reactions caused by both substances are reversible. The minimal effective dose of either sorbitol or trehalose was approximately 0.2 M, a value similar to the in vivo concentration of sorbitol in diapausing eggs (0.2 M). Glycerol, mannitol or glucose were moderately effective for inhibition. Sorbitol present in diapausing silkworm eggs does not appear to serve as an antifreeze, but as an strong arresting factor of embryonic development. Furthermore, these results show that a decrease in sorbitol releases the embryos from diapause at the termination of diapause.

  17. Antiaging Glycopeptide Protects Human Islets Against Tacrolimus-Related Injury and Facilitates Engraftment in Mice.

    Science.gov (United States)

    Gala-Lopez, Boris L; Pepper, Andrew R; Pawlick, Rena L; O'Gorman, Doug; Kin, Tatsuya; Bruni, Antonio; Abualhassan, Nasser; Bral, Mariusz; Bautista, Austin; Manning Fox, Jocelyn E; Young, Lachlan G; MacDonald, Patrick E; Shapiro, A M James

    2016-02-01

    Clinical islet transplantation has become an established treatment modality for selected patients with type 1 diabetes. However, a large proportion of transplanted islets is lost through multiple factors, including immunosuppressant-related toxicity, often requiring more than one donor to achieve insulin independence. On the basis of the cytoprotective capabilities of antifreeze proteins (AFPs), we hypothesized that supplementation of islets with synthetic AFP analog antiaging glycopeptide (AAGP) would enhance posttransplant engraftment and function and protect against tacrolimus (Tac) toxicity. In vitro and in vivo islet Tac exposure elicited significant but reversible reduction in insulin secretion in both mouse and human islets. Supplementation with AAGP resulted in improvement of islet survival (Tac(+) vs. Tac+AAGP, 31.5% vs. 67.6%, P < 0.01) coupled with better insulin secretion (area under the curve: Tac(+) vs. Tac+AAGP, 7.3 vs. 129.2 mmol/L/60 min, P < 0.001). The addition of AAGP reduced oxidative stress, enhanced insulin exocytosis, improved apoptosis, and improved engraftment in mice by decreasing expression of interleukin (IL)-1β, IL-6, keratinocyte chemokine, and tumor necrosis factor-α. Finally, transplant efficacy was superior in the Tac+AAGP group and was similar to islets not exposed to Tac, despite receiving continuous treatment for a limited time. Thus, supplementation with AAGP during culture improves islet potency and attenuates long-term Tac-induced graft dysfunction. PMID:26581595

  18. 昆虫抗冻蛋白及其在医学领域中的应用

    Institute of Scientific and Technical Information of China (English)

    闫清华; 闫欣; 丰慧根; 杨理

    2007-01-01

    抗冻蛋白(antifreeze protein,AFP)是一类结构多样的蛋白质,具有热滞效应(thermal hysteresis,TH,降低冰点而不改变熔点)和重结晶抑制效应(recrystalization inhabition,RI)。通过非共价吸附抑制机制吸附到冰核表面,限制冰晶生长和抑制冰晶重结晶,从而保护有机体免受结冰引起的伤害。由于抗冻蛋白具有阻止冰晶生长而不破坏细胞的特点,因而利用抗冻蛋白在低温中长期保存各种细胞、组织和器官,特别在器官移植中可能具有很好的应用前景。

  19. Ice-crust and ice-film; Miaraban

    Energy Technology Data Exchange (ETDEWEB)

    Nihei, M. [Mechanical Engineering Lab., Tokyo (Japan)

    1999-11-01

    Snow on the road is converted into packed snow after being repeatedly trodden by automobile tires and pedestrians. During this compaction process, a phenomenon named sintering occurs inside the snow. Snow crystals at a temperature below the melting point are transformed into roundish ice grains with the passage of time, and bondage develops between the grains for the formation of a pack of snow which is very hard (hard-packed snow). This prepares the base for ice-film or ice-crust formation. What is called 'mirror-bahn' is an ice film which is 1mm thick or less. It is a mirror-like ice surface, generally termed the 'slippery packed snow or slippery road surface.' With studded tires repeatedly travelling on the hard-packed snow surface, friction heat is generated due to microscopic slips occurring between the tires in rotation and the ground and due to braking or driving, and the heat melts the very thin surface layer of the hard-packed snow. The surface freezes again for the formation of an ice film presenting a mirror-like surface. Such a slippery road surface is formed under complicatedly variable conditions with the parameters involving weather conditions and traffic density. The primary measure against the slippery road surface is the surface control by use of antifreezing agents. (NEDO)

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

    Science.gov (United States)

    Nah, Gyoungju; Lee, Moonsub; Kim, Do-Soon; Rayburn, A Lane; Voigt, Thomas; Lee, D K

    2016-01-01

    Prairie cordgrass (Spartina pectinata), a perennial C4 grass native to the North American prairie, has several distinctive characteristics that potentially make it a model crop for production in stressful environments. However, little is known about the transcriptome dynamics of prairie cordgrass despite its unique freezing stress tolerance. Therefore, the purpose of this work was to explore the transcriptome dynamics of prairie cordgrass in response to freezing stress at -5°C for 5 min and 30 min. We used a RNA-sequencing method to assemble the S. pectinata leaf transcriptome and performed gene-expression profiling of the transcripts under freezing treatment. Six differentially expressed gene (DEG) groups were categorized from the profiling. In addition, two major consecutive orders of gene expression were observed in response to freezing; the first being the acute up-regulation of genes involved in plasma membrane modification, calcium-mediated signaling, proteasome-related proteins, and transcription regulators (e.g., MYB and WRKY). The follow-up and second response was of genes involved in encoding the putative anti-freezing protein and the previously known DNA and cell-damage-repair proteins. Moreover, we identified the genes involved in epigenetic regulation and circadian-clock expression. Our results indicate that freezing response in S. pectinata reflects dynamic changes in rapid-time duration, as well as in metabolic, transcriptional, post-translational, and epigenetic regulation. PMID:27032112

  1. Modern coolant additives. Environmental friendly and light metal compatible coolant additives for modern combustion engines; Moderne Kuehlmittelzusaetze. Umwelt- und leichtmetallvertraegliche Kuehlmittelzusaetze fuer moderne Verbrennungskraftmaschinen. Abschlussbericht. Vorhaben Nr. 777

    Energy Technology Data Exchange (ETDEWEB)

    Gugau, M.; Kaiser, M.

    2004-01-31

    The authors of the contribution under consideration report on the influence of the enhanced thermal stress on the impact of environmental friendly and light metal compatible coolant additives. The application and advancement of new research methods under mechanism-oriented objective led to a validation of a new guideline to the examination of the suitability of coolant additives for the coolant of internal combustion engines. Moreover, the authors create a knowledge base, on which a purposeful development can take place from suitable formulations of inhibitor for magnesium. For aluminium with silicate containing corrosion anti-freezes a close relationship between the surface temperature and the impoverishment of silicate exists. During the excess of limit temperatures, cooling agent-specific damage features arise reproducibly. The comparison of the different methods for the investigation of cavitation showed that one cannot dispense with both methods in order to evaluate a demand of insulating cavitation and a cavitative / corrosive complex regarding to the development of a test guideline. By the comprehensive electro-chemical and cavitative investigations for the magnesium alloy AZ91hp, a broad knowledge base could be formed, on which a purposeful development and evaluation of inhibitors under the use can take place from different glycols.

  2. 聚羧酸系高效减水剂在铁路预制箱梁中的应用%Application of the polycarboxylic high range water reducer on railway precast box beam

    Institute of Scientific and Technical Information of China (English)

    王宏

    2009-01-01

    介绍了聚羧酸系高效减水剂在高性能混凝土中的应用情况,使用表明聚羧酸系高效减水剂具有减水率高、水泥适应性好、坍落度损失小、可泵性及和易性好、水泥用量低、早期强度高、收缩变形小并兼有防冻作用等一系列优势,已成为国内外外加剂应用的热点.%The author introduces the application situation of the polycarboxylic high range water reducer on high performance concrete. The u-tilization proves that the polycarboxylic high range water reducer has a series of advantages, such as high water-reducing rate, good cement adaptability, less slump losses, good purnpability and workability, low cement utilization quantity, high strength and less shrinkage deforma-tion and antifreezing effect, and the polycarboxylic high range water reducer has becoming hot point of admixture application at home and abroad.

  3. Neofunctionalization of zona pellucida proteins enhances freeze-prevention in the eggs of Antarctic notothenioids

    Science.gov (United States)

    Cao, Lixue; Huang, Qiao; Wu, Zhichao; Cao, Dong-Dong; Ma, Zhanling; Xu, Qianghua; Hu, Peng; Fu, Yanxia; Shen, Yu; Chan, Jiulin; Zhou, Cong-Zhao; Zhai, Wanying; Chen, Liangbiao

    2016-10-01

    The mechanisms by which the eggs of the Antarctic notothenioid fishes avoid freezing are not fully understood. Zona pellucida proteins (ZPs) are constituents of the chorion which forms a protective matrix surrounding the egg. Here we report occurrence of freezing temperature-related gene expansion and acquisition of unusual ice melting-promoting (IMP) activity in a family of Antarctic notothenioid ZPs (AnnotoZPs). Members of AnnotoZPs are shown to bind with ice and non-colligatively depress the melting point of a solution in a range of 0.26 to 0.65 °C at a moderate concentration. Eggs of zebrafishes expressing an AnnotoZP transgene show improved melting point depression and enhanced survival in freezing conditions. Mutational analyses in a representative AnnotoZP indicate the ZP domain and patches of acidic residues are essential structures for the IMP activity. AnnotoZPs, therefore, represent a group of macromolecules that prevent freezing by a unique ZP-ice interaction mechanism distinct from the known antifreeze proteins.

  4. The preliminary study on the new culture model of wine grape in the area of the east foot of Helan Mountain%贺兰山东麓酿酒葡萄新型栽培模式探索

    Institute of Scientific and Technical Information of China (English)

    马永明; 陈建琴; 张军翔

    2011-01-01

    The root of grapes in the Helan Mountain area cultivated in large-scale,is always damaged in the winter time,so it leads absence plant in the vineyard and low-yield performance.In this experimentation,by trenching for soil,shallow planting,rational close planting and thinning,changes the grape trellis type and other technology,we achieved the good results of antifreeze,reducing production costs,improving efficiency,and increasing revenue,and the cultivation mode is conversion from low efficient to high efficient.%贺兰山酿酒葡萄在规模化栽培过程中,受到了根系冻害、葡萄园缺株导致形成大面积低产园的情况.本实验通过挖沟换土、浅沟栽植、合理密植与间苗、改变架型等技术,实现防冻,降低生产成本,提高效益,增加收入,从低效栽培模式向高效栽培模式转化.

  5. Ice Recrystallization in a Solution of a Cryoprotector and Its Inhibition by a Protein: Synchrotron X-Ray Diffraction Study.

    Science.gov (United States)

    Zakharov, Boris; Fisyuk, Alexander; Fitch, Andy; Watier, Yves; Kostyuchenko, Anastasia; Varshney, Dushyant; Sztucki, Michael; Boldyreva, Elena; Shalaev, Evgenyi

    2016-07-01

    Ice formation and recrystallization is a key phenomenon in freezing and freeze-drying of pharmaceuticals and biopharmaceuticals. In this investigation, high-resolution synchrotron X-ray diffraction is used to quantify the extent of disorder of ice crystals in binary aqueous solutions of a cryoprotectant (sorbitol) and a protein, bovine serum albumin. Ice crystals in more dilute (10 wt%) solutions have lower level of microstrain and larger crystal domain size than these in more concentrated (40 wt%) solutions. Warming the sorbitol-water mixtures from 100 to 228 K resulted in partial ice melting, with simultaneous reduction in the microstrain and increase in crystallite size, that is, recrystallization. In contrast to sorbitol solutions, ice crystals in the BSA solutions preserved both the microstrain and smaller crystallite size on partial melting, demonstrating that BSA inhibits ice recrystallization. The results are consistent with BSA partitioning into quasi-liquid layer on ice crystals but not with a direct protein-ice interaction and protein sorption on ice surface. The study shows for the first time that a common (i.e., not-antifreeze) protein can have a major impact on ice recrystallization and also presents synchrotron X-ray diffraction as a unique tool for quantification of crystallinity and disorder in frozen aqueous systems.

  6. Inhibition of ice growth and recrystallization by zirconium acetate and zirconium acetate hydroxide.

    Science.gov (United States)

    Mizrahy, Ortal; Bar-Dolev, Maya; Guy, Shlomit; Braslavsky, Ido

    2013-01-01

    The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs), present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA) was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH), on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications.

  7. Carbohydrate-based ice recrystallization inhibitors increase infectivity and thermostability of viral vectors.

    Science.gov (United States)

    Ghobadloo, Shahrokh M; Balcerzak, Anna K; Gargaun, Ana; Muharemagic, Darija; Mironov, Gleb G; Capicciotti, Chantelle J; Briard, Jennie G; Ben, Robert N; Berezovski, Maxim V

    2014-01-01

    The inability of vaccines to retain sufficient thermostability has been an obstacle to global vaccination programs. To address this major limitation, we utilized carbohydrate-based ice recrystallization inhibitors (IRIs) to eliminate the cold chain and stabilize the potency of Vaccinia virus (VV), Vesicular Stomatitis virus (VSV) and Herpes virus-1 (HSV-1). The impact of these IRIs was tested on the potency of the viral vectors using a plaque forming unit assay following room temperature storage, cryopreservation with successive freeze-thaw cycles and lyophilization. Viral potency after storage with all three conditions demonstrated that N-octyl-gluconamide (NOGlc) recovered the infectivity of shelf stored VV, 5.6 Log₁₀ PFU mL(-1) during 40 days, and HSV-1, 2.7 Log₁₀ PFU mL(-1) during 9 days. Carbon-linked antifreeze glycoprotein analogue ornithine-glycine-glycine-galactose (OGG-Gal) increases the recovery of VV and VSV more than 1 Log₁₀ PFU mL(-1) after 10 freeze-thaw cycles. In VSV, cryostorage with OGG-Gal maintains high infectivity and reduces temperature-induced aggregation of viral particles by 2 times that of the control. In total, OGG-Gal and NOGlc preserve virus potency during cryostorage. Remarkably, NOGlc has potential to eliminate the cold chain and permit room temperature storage of viral vectors.

  8. Inhibition of ice growth and recrystallization by zirconium acetate and zirconium acetate hydroxide.

    Directory of Open Access Journals (Sweden)

    Ortal Mizrahy

    Full Text Available The control over ice crystal growth, melting, and shaping is important in a variety of fields, including cell and food preservation and ice templating for the production of composite materials. Control over ice growth remains a challenge in industry, and the demand for new cryoprotectants is high. Naturally occurring cryoprotectants, such as antifreeze proteins (AFPs, present one solution for modulating ice crystal growth; however, the production of AFPs is expensive and inefficient. These obstacles can be overcome by identifying synthetic substitutes with similar AFP properties. Zirconium acetate (ZRA was recently found to induce the formation of hexagonal cavities in materials prepared by ice templating. Here, we continue this line of study and examine the effects of ZRA and a related compound, zirconium acetate hydroxide (ZRAH, on ice growth, shaping, and recrystallization. We found that the growth rate of ice crystals was significantly reduced in the presence of ZRA and ZRAH, and that solutions containing these compounds display a small degree of thermal hysteresis, depending on the solution pH. The compounds were found to inhibit recrystallization in a manner similar to that observed in the presence of AFPs. The favorable properties of ZRA and ZRAH suggest tremendous potential utility in industrial applications.

  9. SINGLE-PHASE AND TWO-PHASE SECONDARY COOLANTS: SIMULATION AND EVALUATION OF THEIR THERMOPHYSICAL PROPERTIES

    Directory of Open Access Journals (Sweden)

    Pedro Samuel Gomes Medeiros

    2011-09-01

    Full Text Available This paper makes a comparative analysis of the thermophysical properties of ice slurry with conventional single-phase secondary fluids used in thermal storage cooling systems. The ice slurry is a two-phase fluid consisting of water, antifreeze and ice crystals. It is a new technology that has shown great energy potential. In addition to transporting energy as a heat transfer fluid, it has thermal storage properties due to the presence of ice, storing coolness by latent heat of fusion. The single-phase fluids analyzed are water-NaCl and water-propylene glycol solutions, which also operate as carrier fluids in ice slurry. The presence of ice changes the thermophysical properties of aqueous solutions and a number of these properties were determined: density, thermal conductivity and dynamic viscosity. Data were obtained by software simulation. The results show that the presence of 10% by weight of ice provides a significant increase in thermal conductivity and dynamic viscosity, without causing changes in density. The rheological behavior of ice slurries, associated with its high viscosity, requires higher pumping power; however, this was not significant because higher thermal conductivity allows a lower mass flow rate without the use of larger pumps. Thus, the ice slurry ensures its high potential as a secondary fluid in thermal storage cooling systems, proving to be more efficient than single-phase secondary fluids.

  10. BIOTECHNOLOGY OF THE FISH AQUACULTURE

    Directory of Open Access Journals (Sweden)

    L. P. Buchatsky

    2013-12-01

    Full Text Available The latest progress in biotechnology on fish aquaculture and different modern methods of investigations for increasing of fish productivity in aquaculture are analyzed. Except for the applied aspect, the use of modern biotechnological methods of investigations opens new possibilities for fundamental researches of sex-determining mechanisms, polyploidy, distant hybridization, and developmental biology of bony fishes. Review contains examples of utilizing modern biotechnology methods to obtain transgenic fishes with accelerated growth and for designing surrogate fishes. Methods for receiving unisexual shoals of salmon and sturgeon female fishes with the view of obtaining a large quantity of caviar, as well as receiving sterile (triploid fishes are analyzed. Great attention is given to androgenesis, particularly to disperm one, in connection with the problem of conserving rare and vanishing fish species using only sperm genetic material. Examples how distant hybrids may be obtained with the use of disperm androgenesis and alkylated DNA are given. Methods of obtaining fish primordium germ cells, recent developments in cultivation of fish stem cells and their use in biotechnology, as well as ones of transplantation of oogonium and spermatogonium to obtain surrogate fishes. The examples of successful experiments on spermatogonial xenotransplantation and characteristic of antifreezing fish proteins and also the prospect of their practical usage are given.

  11. Biodiversity and cold adaptive mechanisms of psychrophiles

    Directory of Open Access Journals (Sweden)

    Yuhua Xin

    2013-07-01

    Full Text Available Cold-adapted bacteria and archaea are widely distributed in cold environments on Earth, such as permafrost, cold soils and deserts, glaciers, lakes, sea ice in the Arctic, Antarctic and high mountains, as well as the deep sea, ice caves and the atmospheric stratosphere etc. Cold-adapted organisms inhabiting these environments exhibit rich diversity. Studies on the biogeography of psychrophiles will enable us to understand their biodiversity, distribution and origins. Due to long-term living in cold regions, cold-adapted bacteria and archeae have developed specific physiological mechanisms of adaptation to cold environments. These mechanisms include: regulating the fluidity of the cytoplasmic membrane through adjusting the composition of membrane lipids; achieving low-temperature protection through compatibility solute, antifreeze proteins, ice-binding proteins, ice-nucleation proteins and anti-nucleating proteins; production of heat-shock and coldshock proteins, cold acclimation protein and DEAD-box RNA helicase at low temperatures; production of cold-active enzymes; increasing energy generation and conservation. With the rapid development of sequencing technology, various omics-based approaches have been used to reveal cold-adaptive mechanisms of psychrophiles at the genomic level.

  12. Characterization of a family of ice-active proteins from the Ryegrass, Lolium perenne.

    Science.gov (United States)

    Kumble, Krishnanand D; Demmer, Jerome; Fish, Steven; Hall, Claire; Corrales, Sofia; DeAth, Angela; Elton, Clare; Prestidge, Ross; Luxmanan, Selvanesan; Marshall, Craig J; Wharton, David A

    2008-12-01

    Five genes coding for ice-active proteins were identified from an expressed sequence tag database of Lolium perenne cDNA libraries. Each of the five genes were characterized by the presence of an N-terminal signal peptide, a region enriched in hydrophilic amino acids and a leucine-rich region in four of the five genes that is homologous with the receptor domain of receptor-like protein kinases of plants. The C-terminal region of all five genes contains sequence homologous with Lolium and Triticum ice-active proteins. Of the four ice-active proteins (IAP1, IAP2, IAP3 and IAP5) cloned, three could be expressed in Escherichia coli and recovered in a functional form in order to study their ice activity. All three ice-active proteins had recrystallization inhibition activity but showed no detectable antifreeze or ice nucleation activity at the concentration tested. IAP2 and IAP5 formed distinct hexagonal-shaped crystals in the nanolitre osmometer as compared to the weakly hexagonal crystals produced by IAP3. PMID:18835384

  13. Novel dimeric β-helical model of an ice nucleation protein with bridged active sites

    Directory of Open Access Journals (Sweden)

    Walker Virginia K

    2011-09-01

    Full Text Available Abstract Background Ice nucleation proteins (INPs allow water to freeze at high subzero temperatures. Due to their large size (>120 kDa, membrane association, and tendency to aggregate, an experimentally-determined tertiary structure of an INP has yet to be reported. How they function at the molecular level therefore remains unknown. Results Here we have predicted a novel β-helical fold for the INP produced by the bacterium Pseudomonas borealis. The protein uses internal serine and glutamine ladders for stabilization and is predicted to dimerize via the burying of a solvent-exposed tyrosine ladder to make an intimate hydrophobic contact along the dimerization interface. The manner in which PbINP dimerizes also allows for its multimerization, which could explain the aggregation-dependence of INP activity. Both sides of the PbINP structure have tandem arrays of amino acids that can organize waters into the ice-like clathrate structures seen on antifreeze proteins. Conclusions Dimerization dramatically increases the 'ice-active' surface area of the protein by doubling its width, increasing its length, and presenting identical ice-forming surfaces on both sides of the protein. We suggest that this allows sufficient anchored clathrate waters to align on the INP surface to nucleate freezing. As PbINP is highly similar to all known bacterial INPs, we predict its fold and mechanism of action will apply to these other INPs.

  14. Probing the Biomimetic Ice Nucleation Inhibition Activity of Poly(vinyl alcohol) and Comparison to Synthetic and Biological Polymers.

    Science.gov (United States)

    Congdon, Thomas; Dean, Bethany T; Kasperczak-Wright, James; Biggs, Caroline I; Notman, Rebecca; Gibson, Matthew I

    2015-09-14

    Nature has evolved many elegant solutions to enable life to flourish at low temperatures by either allowing (tolerance) or preventing (avoidance) ice formation. These processes are typically controlled by ice nucleating proteins or antifreeze proteins, which act to either promote nucleation, prevent nucleation or inhibit ice growth depending on the specific need, respectively. These proteins can be expensive and their mechanisms of action are not understood, limiting their translation, especially into biomedical cryopreservation applications. Here well-defined poly(vinyl alcohol), synthesized by RAFT/MADIX polymerization, is investigated for its ice nucleation inhibition (INI) activity, in contrast to its established ice growth inhibitory properties and compared to other synthetic polymers. It is shown that ice nucleation inhibition activity of PVA has a strong molecular weight dependence; polymers with a degree of polymerization below 200 being an effective inhibitor at just 1 mg.mL(-1). Other synthetic and natural polymers, both with and without hydroxyl-functional side chains, showed negligible activity, highlighting the unique ice/water interacting properties of PVA. These findings both aid our understanding of ice nucleation but demonstrate the potential of engineering synthetic polymers as new biomimetics to control ice formation/growth processes. PMID:26258729

  15. 桂林市盆栽园林植物冻害的调查与分析%Investigation and analysis of freezing injury for potted garden plants in Guilin

    Institute of Scientific and Technical Information of China (English)

    中华

    2012-01-01

    通过对桂林市不同立地环境、不同品种类型、不同栽培技术、不同保护措施的条件下主要盆栽园林植物受冻害的调查与分析,发现在应对园林植物防冻方面存在着对园林植物耐寒性考虑不周,防寒措施不完善,防寒力度分散,防寒系统性不强等不足,并提出防止园林植物受冻的保护方法和措施。%Through investigating and analysing the frost damaging garden plants in the different sites,different varieties of types,different cultivation techniques and different protection conditions in Guilin, the result showed that there were insufficient in response to antifreeze of garden plants such as cold ill-considered on garden plants, cold imperfect measures,and cold systematic is not strong enough and so on and put forward protection methods and mea- sures to prevent garden plants from frost damaging

  16. Surface Morphology of Ice and Ice with AFGP studied with Atomic Force Microscopy

    Science.gov (United States)

    Zepeda, Salvador; Orme, Christine A.; Yeh, Yin

    2001-03-01

    Water is earth's only naturally occurring inorganic liquid and as such it is not surprising that the special properties of water and ice are responsible for life. As essential as it is for survival of living organisms, it can also cause death by freezing in cold weather organisms causing cells to burst upon expansion and recrystallization. Many organisms have developed a tolerance to both freezing and recrystallization. In particular, certain polar and near polar fish have done so in the form of antifreeze glycoproteins (AFGPs). These proteins suppress the freezing temperature of water and inhibit recrystallization. The focus of our efforts is to understand the mechanism by which these proteins function. The working hypothesis has been a Gibbs-Thomson model in which the protein binds to an ice plane and physically impedes its growth. Atomic force microscopy offers molecular level resolution and this type of phenomenon has been readily investigated for other systems with this technique. We will discuss the results from AFM measurements on single ice crystals carried out in an octane overlayer for both the pure phase and in the presence of AFGPs. Our results implicate a high surface mobility of water molecules in both cases.

  17. Atomic force microscope chamber for in situ studies of ice

    Science.gov (United States)

    Zepeda, Salvador; Yeh, Yin; Orme, Christine A.

    2001-11-01

    To investigate the surface morphologies of biological systems in a controlled gaseous environment (e.g., the temperature, humidity and composition), most commercial atomic force microscopes require modification. We have designed a double-jacketed environmental chamber specifically for a Nanoscope IIIa (Digital Instruments, Santa Barbara, CA) force microscope. We use cold nitrogen and thermoelectric devices to control the temperature in the chamber; the nitrogen simultaneously serves to create an inert environment. We have also designed a temperature controlled sample stage utilizing thermoelectric devices for fine temperature regulation. A variation of this sample stage allows us to image samples in fluids at cold temperatures with an O-ringless configuration. The relative humidity within the chamber is also measured with commercially available relative humidity sensors. We investigate the surface morphology of ice Ih in its pure phase and shall extend the study to ice in the presence of biological molecules, such as antifreeze proteins. We present a detailed description of our design and our first images of polycrystalline ice and single crystals of ice grown in situ from the vapor.

  18. Investigation of frost heave prevention using permeable subgrade structure

    Institute of Scientific and Technical Information of China (English)

    DeGou Cai; JianPing Yao; HongYe Yan; QianLi Zhang; AiJun Cheng; Jie Liu

    2015-01-01

    This paper set up a series of comprehensive targets based on the concept of 'anti-freeze filler', which include reasonable water retention rate, frost heave characteristics, and compaction characteristics of filling material. Then, a type of permeable graded gravel is proposed, suitable for high-speed railway subgrade. A series of in-door water retention, permeability, and frost heave tests were performed under different graded conditions. Water retention, permeability, and frost heave characteristic of dif-ferent graded filling materials can be determined, in order to define the gradation range of permeable graded gravel. Relying on the frost-heave monitoring record of high speed railway in Northeast China, a series of experimental studies were per-formed, which included on-site filler production, compaction test, and the anti-frost effect test, in order to improve the pro-duction and compaction techniques of permeable graded gravel. From the research of this paper, the use of permeable graded gravel subgrade as the anti-frost structure for the high-speed railway subgrade in cold areas is feasible.

  19. 几种冷冻新技术对食品冻结过程中冰晶形成的影响%Effect of novel freezing technologies on ice crystals during food freezing

    Institute of Scientific and Technical Information of China (English)

    赵金红; 胡锐; 刘冰; 倪元颖

    2012-01-01

    Freezing technologies play an important role in modern food processing and water crystallization process is the key step determining the freezing process. In this paper, several emerging techniques are introduced to improve the crystallization of water during freezing, including high-pressure freezing, ultrasound assisted freezing, osmotic dehydrofreezing, antifreeze proteins, ice-nucleation active proteins and other new technologies. Moreover, the mechanism of novel methods affecting ice crystals is explained to understand, predict and control the crystallization process, thus improving the freezing process and the quality of the frozen product.%冷冻技术在现代食品加工工业中起着十分重要的作用,水结晶是冷冻过程的关键步骤.文章介绍几种冷冻新技术对食品冻结过程中水结晶的影响的研究进展,包括高压冷冻、超声波冷冻、渗透脱水冷冻、抗冻蛋白、冰核活性蛋白以及其它冷冻新技术.并阐述这些新技术对冰晶的影响机制,旨在能够更好地了解、预测及控制水结晶的过程,并进一步改进冷冻过程和提高冷冻食品的品质.

  20. Extremophiles and their application to veterinary medicine

    Directory of Open Access Journals (Sweden)

    Irwin Jane A

    2004-06-01

    Full Text Available Extremophiles are organisms that can grow and thrive in harsh conditions, e.g., extremes of temperature, pH, salinity, radiation, pressure and oxygen tension. Thermophilic, halophilic and radiation-resistant organisms are all microbes, some of which are able to withstand multiple extremes. Psychrophiles, or cold-loving organisms, include not only microbes, but fish that live in polar waters and animals that can withstand freezing. Extremophiles are structurally adapted at a molecular level to withstand these conditions. Thermophiles have particularly stable proteins and cell membranes, psychrophiles have flexible cellular proteins and membranes and/or antifreeze proteins, salt-resistant halophiles contain compatible solutes or high concentrations of inorganic ions, and acidophiles and alkaliphiles are able to pump ions to keep their internal pH close to neutrality. Their interest to veterinary medicine resides in their capacity to be pathogenic, and as sources of enzymes and other molecules for diagnostic and pharmaceutical purposes. In particular, thermostable DNA polymerases are a mainstay of PCR-based diagnostics.

  1. Design and Model Test of Cement Concrete Pavement Slab Based on Phase Change and Temperature Control%相变控温水泥混凝土路面板设计及模型试验

    Institute of Scientific and Technical Information of China (English)

    高英力; 胡柏学; 贺敬; 杨文剑

    2011-01-01

    Based on the phase change energy storage material and functionally-graded material design method, the conventional structure of cement concrete pavement slab was designed for enhancing the function of anti-freezing and wear-resistance, and the model test of pavement slab was carried out. The step cooling test method was adopted to select the composite phase change material, and then it was placed in the high-strength seamless steel pipe. The size of the formed cement concrete pavement slab model was 500 mm × 400 mm × 80 mm. Anti-freezing and wearresistance property test of the model was carried out. Results indicate that phase change temperature point of the selected phase change material is about 5 ℃, and at the point, the liquidsolid phase transition happens to reject heat which can play better ice-melting effect and delay or control the low-temperature freezing phenomena of the pavement slab model surface. The wearresistance of the pavement slab surface material is excellent and its 28-day wear rate is only 51.9% of the standard limited value. The reinforced role of steel pipe in the phase change function layer can prevent the problem of inconsistent volume deformation between the main structure layer and surface layer and also can enhance interface stability.%引入相变储能材料及梯度功能材料设计方法,对传统水泥混凝土路面板结构进行防冻、耐磨功能设计,开展路面板模型试验研究.采取步冷试验方法,将优选出的复合相变储能材料封装入高强度无缝钢管中,制成500 mm×400 mm×80 mm的水泥混凝土路面板模型,进行模型的防冻性能和耐磨性能试验.结果表明:优选的相变材料体系相变温度点可控制在5℃左右,并产生液-固相变过程,放出热量,起到了较好的融冰效果,延缓或控制了路面板模型表面的低温冰冻现象;表面层材料耐磨性优良,28 d磨耗率仅为标准限值的51.9%;相变功能层中钢管的加筋作用可防止主

  2. 冻融后小鼠休眠胚胎超微结构的变化%Ultrastructural observation of dormant mouse embryos cultured in vitro after freezing-thawing

    Institute of Scientific and Technical Information of China (English)

    顾美超; 卢天罡; 刘云海; 倪和民; 张劭俣; 翟椿东; 邢书涵; 郭勇

    2014-01-01

    Objective The aim of this study was to investigate the differences of the cell ultrastucture of normal mouse hatched blastocysts and their dormant ones cultured in vitro after freezing-thawing, and to explore whether the dor-mant embryos have a better anti-freezing shock property than the normal hatched mouse embryos .Methods By transmis-sion electron microscopy , the ultrastructure of these two types of mouse embryos was observed and analyzed .Results By comparative analysis of their ultrastructure , the results showed that the dormant embryos before freezing are being austerity and with lower energy metabolism at a ‘ground state ’ .After freezing-thawing and culture , their cellular structure seemed to be similar to that of the normal embryos cultured in vitro before freezing.However, after freezing-thawing and culture, the number of mitochondria decreased , the nuclei were loose , and their heterochromatin also increased .Conclusions From the ultrastructural observation , compared with the normal mouse hatched embryos , the cellular state of dormant mouse em-bryos after freezing-thawing is more favorable for material storage and energy metabolism , thus, indicating that they have a better anti-freezing property than normal hatched embryos .%目的:从亚细胞超微结构的角度揭示其抗冻能力优于正常孵化胚胎的原因。方法利用透射电子显微镜观察小鼠休眠胚胎与正常孵化期胚胎在细胞连接和各细胞器形态与分布上的差异,以及冻融培养后的变化,并进行相关比较分析。结果通过亚细胞结构对比分析发现:冷冻前小鼠休眠胚胎为紧缩状,处于能量代谢较低的“基态”,通过冻融后培养,细胞器结构恢复与正常孵化胚胎冷冻前相似;而正常孵化胚胎经过冻融后,线粒体数量减少,细胞核松散,异染色质增多。结论小鼠休眠胚胎与正常孵化胚胎冻融后相比,其细胞状态更有利于物质储存及能

  3. Information draft on the development of air standards for methanol

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-01-01

    Methanol is a clear, colourless. very mobile liquid with a slightly alcoholic odour in pure form, but a repulsive pungent odour in crude form. Methanol is the raw material in the production of many gasoline additives, is used as a solvent or antifreeze in paint strippers, aerosol spray paints, wall paints, carburetor cleaners, and car windshield washer compounds. Methanol is one of the top pollutants by release quantities in Ontario, the highest release being generated by the pulp and paper industry. Other large emissions come from the plastics and synthetic resin industry. Total release to the air in Canada was 3,668 tonnes in 1996 and the top ten methanol emitting facilities were in Ontario. Methanol is readily absorbed through inhalation, ingestion and skin exposures. Once absorbed, it is oxidized to formaldehyde and then to formic acid. Common symptoms of exposure are visual disturbances, dizziness, nausea, vertigo, pain in the extremities, and headaches. No information was found as to the carcinogenicity of methanol to humans or animals. Current Ontario half-hour POI standard for methanol is 84,000 microgram/cubic meter and the 24-hour AAQC is 28,000 microgram/cubic meter. Both values were established more than 20 years ago. Review of relevant literature, summarized in this report, indicates that five US states have promulgated air quality guidelines or reference exposure levels for methanol, based on occupational exposure limits. The US Environmental Protection Agency is currently reviewing its reference concentration value for methanol. The World Health Organization and the Canadian federal government have not set air quality guidelines for methanol. 37 refs., 1 tab., appendix.

  4. Unusual case of methanol poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Shapiro, L.; Henderson, M. (St. James' s Univ. Hospital, Leeds (United Kingdom). Dept. of Chemical Pathology); Madi, S.; Mellor, L. (St. James' s Univ. Hospital, Leeds (United Kingdom). Dept. of Medicine, and Pharmacy)

    1993-01-09

    A 31-year-old man with a history of alcohol abuse presented to the accident and emergency department complaining of blurred vision. 4 h previously he had drunk 300 mL de-icer fluid. Electrolytes, urea, creatinine, glucose, and blood-gas analysis were normal. Measured osmolality, however, was 368 mosmol/kg with a calculated osmolality of 300 mosmol/kg, which indicated a greatly increased osmolar gap. He was therefore given 150 mL whisky and admitted. Methanol was later reported as 200 mg/dL. Ethylene glycol was not detected, but another glycol, propylene glycol, was present at 47 mg/dL. 10 h after ingestion an intravenous infusion of ethanol was started and he was hemodialysed for 7 h. After dialysis he was given a further 100 mL whisky and the rate of ethanol infusion was reduced to 11 g per h. Methanol and ethanol were measured twice daily until methanol was under 10/mg/dL: The recommendation is that blood ethanol be maintained between 100 and 200 mg/dL during treatment of methanol poisoning. This concentration was not achieved, presumably because of the high rate of ethanol metabolism often found in alcoholics. Antifreeze solutions commonly contain methanol and ethylene glycol. Sometimes propylene glycol is substituted because it has properties similar to those of ethylene glycol but is less toxic. The authors postulate that propylene glycol inhibited the metabolism of methanol in the patient, thus sparing him from the toxic effects of methanol.

  5. "Nanotechnology Enabled Advanced Industrial Heat Transfer Fluids"

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Ganesh Skandan; Dr. Amit Singhal; Mr. Kenneth Eberts; Mr. Damian Sobrevilla; Prof. Jerry Shan; Stephen Tse; Toby Rossmann

    2008-06-12

    ABSTRACT Nanotechnology Enabled Advanced industrial Heat Transfer Fluids” Improving the efficiency of Industrial Heat Exchangers offers a great opportunity to improve overall process efficiencies in diverse industries such as pharmaceutical, materials manufacturing and food processing. The higher efficiencies can come in part from improved heat transfer during both cooling and heating of the material being processed. Additionally, there is great interest in enhancing the performance and reducing the weight of heat exchangers used in automotives in order to increase fuel efficiency. The goal of the Phase I program was to develop nanoparticle containing heat transfer fluids (e.g., antifreeze, water, silicone and hydrocarbon-based oils) that are used in transportation and in the chemical industry for heating, cooling and recovering waste heat. Much work has been done to date at investigating the potential use of nanoparticle-enhanced thermal fluids to improve heat transfer in heat exchangers. In most cases the effect in a commercial heat transfer fluid has been marginal at best. In the Phase I work, we demonstrated that the thermal conductivity, and hence heat transfer, of a fluid containing nanoparticles can be dramatically increased when subjected to an external influence. The increase in thermal conductivity was significantly larger than what is predicted by commonly used thermal models for two-phase materials. Additionally, the surface of the nanoparticles was engineered so as to have a minimal influence on the viscosity of the fluid. As a result, a nanoparticle-laden fluid was successfully developed that can lead to enhanced heat transfer in both industrial and automotive heat exchangers

  6. Stress-induced accumulation of DcAOX1 and DcAOX2a transcripts coincides with critical time point for structural biomass prediction in carrot primary cultures (Daucus carota L.

    Directory of Open Access Journals (Sweden)

    Maria Doroteia eCampos

    2016-01-01

    Full Text Available Stress-adaptive cell plasticity in target tissues and cells for plant biomass growth is important for yield stability. In vitro systems with reproducible cell plasticity can help to identify relevant metabolic and molecular events during early cell reprogramming. In carrot, regulation of the central root meristem is a critical target for yield-determining secondary growth. Calorespirometry, a tool previously identified as promising for predictive growth phenotyping has been applied to measure the respiration rate in carrot meristem. In a carrot primary culture system (PCS, this tool allowed identifying an early peak related with structural biomass formation during lag phase of growth, around the 4th day of culture. In the present study, we report a dynamic and correlated expression of carrot AOX genes (DcAOX1 and DcAOX2a during PCS lag phase and during exponential growth. Both genes showed an increase in transcript levels until 36 h after explant inoculation, and a subsequent down-regulation, before the initiation of exponential growth. In PCS growing at two different temperatures (21 °C and 28 °C, DcAOX1 was also found to be more expressed in the highest temperature. DcAOX genes’ were further explored in a plant pot experiment in response to chilling, which confirmed the early AOX transcript increase prior to the induction of a specific anti-freezing gene (AFP. Our findings point to DcAOX1 and DcAOX2a as being reasonable candidates for functional marker development related to early cell reprogramming. While the sequence of gDcAOX2a was previously described, we characterize the complete genomic sequence of DcAOX1.

  7. Fish from the Southern Ocean: biodiversity, ecology and conservation challenges

    Directory of Open Access Journals (Sweden)

    Marino Vacchi

    2015-11-01

    Living and functioning at subzero temperatures implied important adaptations, including freezing avoidance by antifreeze glycoproteins ( AFGPs. Among the system-wide adaptive traits holding major ecological implications, the acquisition of secondary pelagicism in some species (plesiomorphically devoid of swim-bladder is a major. In those notothenioids, lipid deposition and reduced ossification allowed to achieve partial or full neutral buoyancy, and enabled expansion into semi-pelagic, pelagic, and cryopelagic habitats. Such an impressive ecological expansion has allowed several notothenioids to play a primary role in the Antarctic marine ecosystems. On the other side, their fine adaptation to the environment, might expose these fishes to risks that need to be properly considered and addressed. For instance, a relationship between the Antarctic silverfish (Pleuragramma antarctica, a key species in the coastal Antarctic ecosystem and the sea-ice, has recently been assessed, thus making this species potentially threatened by the ongoing climatic change, with implications for the whole ecosystem. In addition, some Antarctic fish, such as toothfishes (Dissostichus eleginoides and Dissostichus mawsoni are primary targets of industrial fish harvesting in the SO. To increase and update the scientific knowledge on these species is mandatory in order to improve the management of Antarctic marine resources, in response to the increasing international request of exploitation. This task is presently being conducted by CCAMLR (Commission for the Conservation of Antarctic Marine Living Resources, along with fighting the illegal, unreported and unregulated (IUU fishing and with the establishment of MPAs (Marine Protected Areas in various sectors of the Southern Ocean.

  8. Design, fabrication and thermal characterization of a magnetocaloric microcooler

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.; Ghirlanda, S.; Adams, C.; Bethala, B.; Sambandam, S.N.; Bhansali, S. [BioMEMS and Microsystems Laboratory, Department of Electrical Engineering, University of South Florida, 4202 E. Fowler Ave., ENB118, Tampa, FL 33620, (United States)

    2006-12-11

    Magnetocaloric cooling is an alternative, high-efficiency cooling technology. In this paper, we present the design and fabrication of a micromachined magnetocaloric cooler and demonstrate its ability to work in a small magnetic field (<1.2 T) with a cooling test. The cooler was built by fabricating Si microfluidic channels, and it was integrated with a Gd{sub 5}(Si{sub 2}Ge{sub 2}) magnetocaloric refrigeration element. The magnetic properties of the Gd{sub 5}(Si{sub 2}Ge{sub 2}) material were characterized to calculate the magnetic entropy change at different ambient temperatures. Three different methods to integrate the channel layer and the magnetocaloric element were evaluated to test sealing and cooling performance. The cooling tests were performed by providing a magnetic field using an electromagnet. A test jig was constructed between the poles of an electromagnet to maintain a steady temperature during the test. Cooling tests were performed on the magnetocaloric element at ambient temperatures ranging from 258 to 280 K using a magnetic field of 1.2 T. Experimental results showed a maximum temperature change of 7 K on the magnetocaloric element alone at an ambient temperature of 258 K. Cooling tests of the fully integrated coolers were also performed. A solution of anti-freeze fluid (propylene glycol) and water was used as the coolant. The temperature of the working fluid decreased by 4.6 and 9 K for the glass and Si intermediate layers, respectively, confirming that the thermal conductivity of the materials is also an important factor in cooler performance. (Author)

  9. Oil palm EgCBF3 conferred stress tolerance in transgenic tomato plants through modulation of the ethylene signaling pathway.

    Science.gov (United States)

    Ebrahimi, Mortaza; Abdullah, Siti Nor Akmar; Abdul Aziz, Maheran; Namasivayam, Parameswari

    2016-09-01

    CBF/DREB1 is a group of transcription factors that are mainly involved in abiotic stress tolerance in plants. They belong to the AP2/ERF superfamily of plant-specific transcription factors. A gene encoding a new member of this group was isolated from ripening oil palm fruit and designated as EgCBF3. The oil palm fruit demonstrates the characteristics of a climacteric fruit like tomato, in which ethylene has a major impact on the ripening process. A transgenic approach was used for functional characterization of the EgCBF3, using tomato as the model plant. The effects of ectopic expression of EgCBF3 were analyzed based on expression profiling of the ethylene biosynthesis-related genes, anti-freeze proteins (AFPs), abiotic stress tolerance and plant growth and development. The EgCBF3 tomatoes demonstrated altered phenotypes compared to the wild type tomatoes. Delayed leaf senescence and flowering, increased chlorophyll content and abnormal flowering were the consequences of overexpression of EgCBF3 in the transgenic tomatoes. The EgCBF3 tomatoes demonstrated enhanced abiotic stress tolerance under in vitro conditions. Further, transcript levels of ethylene biosynthesis-related genes, including three SlACSs and two SlACOs, were altered in the transgenic plants' leaves and roots compared to that in the wild type tomato plant. Among the eight AFPs studied in the wounded leaves of the EgCBF3 tomato plants, transcript levels of SlOSM-L, SlNP24, SlPR5L and SlTSRF1 decreased, while expression of the other four, SlCHI3, SlPR1, SlPR-P2 and SlLAP2, were up-regulated. These findings indicate the possible functions of EgCBF3 in plant growth and development as a regulator of ethylene biosynthesis-related and AFP genes, and as a stimulator of abiotic stress tolerance.

  10. Deep Hole Smooth Blasting Crafts Optimization of Vertical Shafts in Huainan Mining Area%淮南矿区立井井筒深孔光面爆破工艺优化

    Institute of Scientific and Technical Information of China (English)

    杨海若

    2015-01-01

    Introduce Huainan Mining Mine Shaft Deep Bore Hole Blasting poor variety of special cir-cumstances ,through the use of high quality drilling tools and instruments ,rational arrangement sur-rounding the eye ,optimizing drill order to improve the quality drill ;the design and use of attempts to prevent the charge pipe ,improve equipment drug quality ;using Mixture film wrapped gun plugged with mud ,fractured formations to enhance the effect of blocking borehole ;freeze bedrock blasting through improved antifreeze formulations and the use of explosives ,detonating cord detonation initia-tion method ,eliminating the effects of poor ,misfire problem ,and ultimately improve the Mine Shaft hole smooth blasting effect ,achieved good effect.%分析了淮南矿区立井井筒深孔光面爆破效果差的各种特殊情况。选用优质打眼器具、合理布置周边眼、优化打眼顺序,提高钻眼质量;设计和使用防堵装药导管,提高装药质量;采用混合料配合薄膜包裹的炮泥进行封孔,提升裂隙发育地层中炮眼的封堵效果;通过使用改良抗冻炸药配方以及导爆索起爆技术,解决了冻结基岩段爆破效果差甚至拒爆等难题,有效提高了立井井筒深孔光面爆破的效果。

  11. Zeolite Y Adsorbents with High Vapor Uptake Capacity and Robust Cycling Stability for Potential Applications in Advanced Adsorption Heat Pumps.

    Science.gov (United States)

    Li, Xiansen; Narayanan, Shankar; Michaelis, Vladimir K; Ong, Ta-Chung; Keeler, Eric G; Kim, Hyunho; McKay, Ian S; Griffin, Robert G; Wang, Evelyn N

    2015-01-01

    Modular and compact adsorption heat pumps (AHPs) promise an energy-efficient alternative to conventional vapor compression based heating, ventilation and air conditioning systems. A key element in the advancement of AHPs is the development of adsorbents with high uptake capacity, fast intracrystalline diffusivity and durable hydrothermal stability. Herein, the ion exchange of NaY zeolites with ingoing Mg(2+) ions is systematically studied to maximize the ion exchange degree (IED) for improved sorption performance. It is found that beyond an ion exchange threshold of 64.1%, deeper ion exchange does not benefit water uptake capacity or characteristic adsorption energy, but does enhance the vapor diffusivity. In addition to using water as an adsorbate, the uptake properties of Mg,Na-Y zeolites were investigated using 20 wt.% MeOH aqueous solution as a novel anti-freeze adsorbate, revealing that the MeOH additive has an insignificant influence on the overall sorption performance. We also demonstrated that the labscale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N2 sorption, (27)Al/(29)Si MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick's 2(nd) law and D-R equation regressions. Among these, close examination of sorption isotherms for H2O and N2 adsorbates allows us to decouple and extract some insightful information underlying the complex water uptake phenomena. This work shows the promising performance of our modified zeolites that can be integrated into various AHP designs for buildings, electronics, and transportation applications.

  12. Distribution of cold adaptation proteins in microbial mats in Lake Joyce, Antarctica: Analysis of metagenomic data by using two bioinformatics tools.

    Science.gov (United States)

    Koo, Hyunmin; Hakim, Joseph A; Fisher, Phillip R E; Grueneberg, Alexander; Andersen, Dale T; Bej, Asim K

    2016-01-01

    In this study, we report the distribution and abundance of cold-adaptation proteins in microbial mat communities in the perennially ice-covered Lake Joyce, located in the McMurdo Dry Valleys, Antarctica. We have used MG-RAST and R code bioinformatics tools on Illumina HiSeq2000 shotgun metagenomic data and compared the filtering efficacy of these two methods on cold-adaptation proteins. Overall, the abundance of cold-shock DEAD-box protein A (CSDA), antifreeze proteins (AFPs), fatty acid desaturase (FAD), trehalose synthase (TS), and cold-shock family of proteins (CSPs) were present in all mat samples at high, moderate, or low levels, whereas the ice nucleation protein (INP) was present only in the ice and bulbous mat samples at insignificant levels. Considering the near homogeneous temperature profile of Lake Joyce (0.08-0.29 °C), the distribution and abundance of these proteins across various mat samples predictively correlated with known functional attributes necessary for microbial communities to thrive in this ecosystem. The comparison of the MG-RAST and the R code methods showed dissimilar occurrences of the cold-adaptation protein sequences, though with insignificant ANOSIM (R = 0.357; p-value = 0.012), ADONIS (R(2) = 0.274; p-value = 0.03) and STAMP (p-values = 0.521-0.984) statistical analyses. Furthermore, filtering targeted sequences using the R code accounted for taxonomic groups by avoiding sequence redundancies, whereas the MG-RAST provided total counts resulting in a higher sequence output. The results from this study revealed for the first time the distribution of cold-adaptation proteins in six different types of microbial mats in Lake Joyce, while suggesting a simpler and more manageable user-defined method of R code, as compared to a web-based MG-RAST pipeline. PMID:26578243

  13. Phase behavior in the system tetrahydrofuran-water-ammonia from calorimetry and Raman spectroscopy

    Science.gov (United States)

    Munoz-Iglesias, Victoria; Vu, Tuan; Choukroun, Mathieu; Hodyss, Robert; Smythe, William; Sotin, Christophe

    2016-10-01

    From geochemical models and Cassini-Huygens mission data it can be postulated that the icy crust of Titan is composed by water ice, clathrate hydrates and ammonia hydrates. When the shell evolves thermically, the first minerals in dissociating are the ammonia hydrates. Ammonia is a powerful antifreeze, promoting the drop of the equilibrium curves of both water ice and clathrates to values as low as 170 K and 203 K respectively. Calorimetry, using a Setaram BT 2.15 Calvet calorimeter, has allowed to identify the different phases formed in the system THF-H2O-NH3 when the molar ratio H2O:THF is 1:X 17, which corresponds with the THF-clathrate stoichiometric ratio, and at NH3 concentrations up to 30 wt%. When X 17, the H2O is in excess; the formation of ammonia hydrates, water ice and THF-clathrate is observed. Since under this condition, all available THF is trapped in the clathrate, no THF-NH3 phase is observed. In all the scenarios, the release of NH3 (from the melting of THF-NH3 solid or ammonia hydrates) promotes partial dissociation of THF clathrates, which start at much lower temperature the equilibrium dissociation of the clathrates. This research is supported by an appointment to the NASA Postdoctoral Program at the Jet Propulsion Laboratory, California Institute of Technology, administered by Universities Space Research Association (USRA) through a contract with NASA. Support from the NASA Outer Planets Research program and government sponsorship acknowledged.

  14. Study of the mechanism of a kinetic inhibitor on the crystallization of methane hydrate; Etude du mecanisme d'action d'un inhibiteur cinetique sur la cristallisation de l'hydrate de methane

    Energy Technology Data Exchange (ETDEWEB)

    Pic, J.St.

    2000-01-14

    In the offshore exploitation of liquid fuels, problems of line plugging often occur, especially due to gas hydrates crystallization. At the present time, operators resort to antifreeze additives, which efficiency is defeated either by harder operating conditions or by a more severe environmental legislation. So research recently shifted towards a new class of 'low dosage inhibitors'. In order to understand the influence of such additives, we designed a high pressure reactor, fitted with a liquid injection device and an in situ turbidimetric sensor. Access to both the particle size distribution of the suspension during the first stages of crystallization, and the total gas consumption, allows us to characterize the kinetics of methane hydration formation. First, we developed an original experimental procedure, which generates an initial 'breeding' of the solution, and thus improves the mastering of nucleation. The induction time then becomes one of the relevant parameters to investigate the performance of inhibitors. Afterwards, we performed a first series of experiments which allowed us to determine the influence of the operating conditions (pressure and stirring) on the evolution of the particle size distribution, in the absence of additives. Then, we pointed out the inhibiting effect of a model kinetic inhibitor, polyvinylpyrrolidone. When dissolved in the solution before crystallization occurs, it increases the induction delay, decreases the gas consumption rate and also slows down the birth of new particles for several hours. On the contrary, when injected in the medium during crystallization, this polymer no more affects the reaction kinetics. At last, we raise the bases for a modelling, taking into account the elementary crystallization processes of nucleation, growth and particles agglomeration. A parametric study has been confronted to the experimental data. It enables us to suggest hypotheses regarding the effect of gas hydrates kinetic

  15. 丹贝冻干菌剂的制备及其工艺条件的优化

    Institute of Scientific and Technical Information of China (English)

    许亮; 陈鑫; 徐速; 许岩; 穆莹

    2014-01-01

    从培养基添加的成分、 pH值、培养温度以及保护剂等方面,研究对丹贝冻干菌剂存活率的影响,并探究菌剂的稳定性。结果表明,当丹贝菌在PDA培养基中加入0.5%山梨醇或0.5%麦芽糖抗冻剂,培养基pH值在6.5或8.5,31℃预培养48 h时,预冻保护剂采用脱脂乳10%,甘油10%,山梨醇15%时,冻干后菌种的存活率最高,可达73.14%,所制备的丹贝冻干菌剂稳定性较好,适合菌种保存。%This paper from the culture medium added ingredients,pH,culture temperature and protective agent and so on, studies effect of stem inocula survival rate of frozen to Tempe,stability and inquiry agent. Research results show that,when the Tempe bacteria in adding 0.5% sorbitol or 0.5% maltose antifreeze agent PDA in the medium,the medium pH in about 6.5 or 8.5,31 ℃pre training 48 h,pre freezing protective agent with skim milk 10%,glycerol 10%,sorbitol 15%, freeze-dried bacteria survival rate is highest,up to 73.14%. Preparation of freeze-dried inoculant Tempe is good stability, suitable for preservation.

  16. The Anion Gap is a Predictive Clinical Marker for Death in Patients with Acute Pesticide Intoxication.

    Science.gov (United States)

    Lee, Sun-Hyo; Park, Samel; Lee, Jung-Won; Hwang, Il-Woong; Moon, Hyung-Jun; Kim, Ki-Hwan; Park, Su-Yeon; Gil, Hyo-Wook; Hong, Sae-Yong

    2016-07-01

    Pesticide formulation includes solvents (methanol and xylene) and antifreeze (ethylene glycol) whose metabolites are anions such as formic acid, hippuric acid, and oxalate. However, the effect of the anion gap on clinical outcome in acute pesticide intoxication requires clarification. In this prospective study, we compared the anion gap and other parameters between surviving versus deceased patients with acute pesticide intoxication. The following parameters were assessed in 1,058 patients with acute pesticide intoxication: blood chemistry (blood urea nitrogen, creatinine, glucose, lactic acid, liver enzymes, albumin, globulin, and urate), urinalysis (ketone bodies), arterial blood gas analysis, electrolytes (Na(+), K(+), Cl(-) HCO3 (-), Ca(++)), pesticide field of use, class, and ingestion amount, clinical outcome (death rate, length of hospital stay, length of intensive care unit stay, and seriousness of toxic symptoms), and the calculated anion gap. Among the 481 patients with a high anion gap, 52.2% had a blood pH in the physiologic range, 35.8% had metabolic acidosis, and 12.1% had acidemia. Age, anion gap, pesticide field of use, pesticide class, seriousness of symptoms (all P < 0.001), and time lag after ingestion (P = 0.048) were significant risk factors for death in univariate analyses. Among these, age, anion gap, and pesticide class were significant risk factors for death in a multiple logistic regression analysis (P < 0.001). In conclusions, high anion gap is a significant risk factor for death, regardless of the accompanying acid-base balance status in patients with acute pesticide intoxication. PMID:27366016

  17. Research and Development of Nutritional and Healthy Function of Sturgeon and its Deep Processing Products%鲟鱼营养保健功能及其深加工产品的开发研究

    Institute of Scientific and Technical Information of China (English)

    王蕊

    2014-01-01

    为提高鲟鱼的养殖效益,探索鲟鱼发展产业链,使更多人享用肉味鲜美、营养保健的鲟鱼产品,通过查阅文献资料,对制约鲟鱼产业瓶颈的主要因素进行了研究。结果表明,由于养殖规模的快速扩张、深加工技术研究相对滞后、农户养殖效益下降,严重制约了该产业的可持续发展。解决鲟鱼蛋白低温抗冻技术,开发鲟鱼速冻调理食品、特色风味休闲食品和针对不同消费人群的功能性食品是鲟鱼产业未来的主要发展方向。%To improve the benefit of the sturgeon breeding,then explore the d industrial chain of evelopment,the sturgeon products,which are delicious,nutrition,care,are enjoyed by more people,the main factors restraining the sturgeon industry was learned through consulting literature material.The results show that because of the rapid expansion of scale of breeding and the relative lag of deep processing technology ,so that the benefit of farmers breeding drop,severely restricted the sustainable development of this industry.So solving the antifreeze technology of sturgeon protein in low temperature,then the sturgeon frozen prepared food,unique flavor snack food and functional food for different consumers will be developed,these are the main development direction of sturgeon industry in the future.

  18. Zeolite Y adsorbents with high vapor uptake capacity and robust cycling stability for potential applications in advanced adsorption heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Li, XS; Narayanan, S; Michaelis, VK; Ong, TC; Keeler, EG; Kim, H; Mckay, IS; Griffin, RG; Wang, EN

    2015-01-01

    Modular and compact adsorption heat pumps (AHPs) promise an energy-efficient alternative to conventional vapor compression based heating, ventilation and air conditioning systems. A key element in the advancement of AHPs is the development of adsorbents with high uptake capacity, fast intracrystalline diffusivity and durable hydrothermal stability. Herein, the ion exchange of NaY zeolites with ingoing Mg2+ ions is systematically studied to maximize the ion exchange degree (IED) for improved sorption performance. It is found that beyond an ion exchange threshold of 64.1%, deeper ion exchange does not benefit water uptake capacity or characteristic adsorption energy, but does enhance the vapor diffusivity. In addition to using water as an adsorbate, the uptake properties of Mg, Na-Y zeolites were investigated using 20 wt.% MeOH aqueous solution as a novel anti-freeze adsorbate, revealing that the MeOH additive has an insignificant influence on the overall sorption performance. We also demonstrated that the lab-scale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N-2 sorption, Al-27/Si-29 MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick's 2nd law and D-R equation regressions. Among these, close examination of sorption isotherms for H2O and N-2 adsorbates allows us to decouple and extract some insightful information underlying the complex water uptake phenomena. This work shows the promising performance of our modified zeolites that can be integrated into various AHP designs for buildings, electronics, and transportation applications. (C) 2014 Elsevier Inc. All rights reserved.

  19. Contingent post-closure plan, hazardous waste management units at selected maintenance facilities, US Army National Training Center, Fort Irwin, California

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The National Training Center (NTC) at Fort Irwin, California, is a US Army training installation that provides tactical experience for battalion/task forces and squadrons in a mid- to high-intensity combat scenario. Through joint exercises with US Air Force and other services, the NTC also provides a data source for improvements of training doctrines, organization, and equipment. To meet the training and operational needs of the NTC, several maintenance facilities provide general and direct support for mechanical devices, equipment, and vehicles. Maintenance products used at these facilities include fuels, petroleum-based oils, lubricating grease, various degreasing solvents, antifreeze (ethylene glycol), transmission fluid, brake fluid, and hydraulic oil. Used or spent petroleum-based products generated at the maintenance facilities are temporarily accumulated in underground storage tanks (USTs), collected by the NTC hazardous waste management contractor (HAZCO), and stored at the Petroleum, Oil, and Lubricant (POL) Storage Facility, Building 630, until shipped off site to be recovered, reused, and/or reclaimed. Spent degreasing solvents and other hazardous wastes are containerized and stored on-base for up to 90 days at the NTC`s Hazardous Waste Storage Facility, Building 703. The US Environmental Protection Agency (EPA) performed an inspection and reviewed the hazardous waste management operations of the NTC. Inspections indicated that the NTC had violated one or more requirements of Subtitle C of the Resource Conservation and Recovery Act (RCRA) and as a result of these violations was issued a Notice of Noncompliance, Notice of Necessity for Conference, and Proposed Compliance Schedule (NON) dated October 13, 1989. The following post-closure plan is the compliance-based approach for the NTC to respond to the regulatory violations cited in the NON.

  20. Contingent post-closure plan, hazardous waste management units at selected maintenance facilities, US Army National Training Center, Fort Irwin, California

    Energy Technology Data Exchange (ETDEWEB)

    1992-01-01

    The National Training Center (NTC) at Fort Irwin, California, is a US Army training installation that provides tactical experience for battalion/task forces and squadrons in a mid- to high-intensity combat scenario. Through joint exercises with US Air Force and other services, the NTC also provides a data source for improvements of training doctrines, organization, and equipment. To meet the training and operational needs of the NTC, several maintenance facilities provide general and direct support for mechanical devices, equipment, and vehicles. Maintenance products used at these facilities include fuels, petroleum-based oils, lubricating grease, various degreasing solvents, antifreeze (ethylene glycol), transmission fluid, brake fluid, and hydraulic oil. Used or spent petroleum-based products generated at the maintenance facilities are temporarily accumulated in underground storage tanks (USTs), collected by the NTC hazardous waste management contractor (HAZCO), and stored at the Petroleum, Oil, and Lubricant (POL) Storage Facility, Building 630, until shipped off site to be recovered, reused, and/or reclaimed. Spent degreasing solvents and other hazardous wastes are containerized and stored on-base for up to 90 days at the NTC's Hazardous Waste Storage Facility, Building 703. The US Environmental Protection Agency (EPA) performed an inspection and reviewed the hazardous waste management operations of the NTC. Inspections indicated that the NTC had violated one or more requirements of Subtitle C of the Resource Conservation and Recovery Act (RCRA) and as a result of these violations was issued a Notice of Noncompliance, Notice of Necessity for Conference, and Proposed Compliance Schedule (NON) dated October 13, 1989. The following post-closure plan is the compliance-based approach for the NTC to respond to the regulatory violations cited in the NON.

  1. Studies on the new fuels with Santilli magnecular structure and their industrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Pandhurnekar, Chandrashekhar P., E-mail: pandhurnekarcp@rknec.edu [Shri Ramdeobaba College of Engineering and Management, Nagpur, Maharashtra 440 013 (India)

    2015-03-10

    Professor R. M. Santilli, the Italian-American physicist, for the first time in the history of Science, presented the theoretical and experimental evidence on the existence of the new chemical species of “magnecules” [1]. This new species mainly consist of individual atoms, radicals and conventional molecules bonded together with stable clusters under the new attractive force primarily originating from torroidal polarization of orbitals of atomic electrons under strong magnetic field. The main contribution in this area was the production of Magnegas{sup TM}, new clean fuels developed by Prof. Santilli, which are produced as byproducts of recycling nonradioactive liquid feedstock such as antifreeze waste, engine oil waste, town sewage, crude oil, etc., and generally vary with the liquid used for their production. A new technology, called Plasma Arc FlowTM, flows the waste through a submerged electric arc between conventional electrodes. The arc decomposes the liquid molecules into their atomic constituents, and forms a plasma in the immediate vicinity of the electrodes at about 10,000{sup 0} F. The technology then moves the plasma away from the electrodes, and controls its recombination into environmentally acceptable fuels. In fact, the exhaust of magnegases shows: absence of carcinogenic or other toxic substances; breathable oxygen up 14 percent; and carbon dioxide down to 0.01 percent. Since, in addition, the new fuels can be produced everywhere, and have environmentally acceptable exhausts, Magnegases offer promising possibilities to satisfy our ever increasing energy needs, as well as to contain the alarming environmental problems caused by fossil fuels. Thus, it was thought worthwhile to present some of the industrial applications of environmentally benign fuel consisting magnecular bonds [2, 3, 4, 5]. Also in the present communications, some of the experimental evidences of Santilli’s new chemical species i. e. Magnecules which had been published

  2. Expression and localization of an ice nucleating protein from a soil bacterium, Pseudomonas borealis.

    Science.gov (United States)

    Vanderveer, Tara L; Choi, Julie; Miao, Denian; Walker, Virginia K

    2014-08-01

    An ice nucleating protein (INP) coding region with 66% sequence identity to the INP of Pseudomonas syringae was previously cloned from P. borealis, a plant beneficial soil bacterium. Ice nucleating activity (INA) in the P. borealis DL7 strain was highest after transfer of cultures to temperatures just above freezing. The corresponding INP coding sequence (inaPb or ina) was used to construct recombinant plasmids, with recombinant expression visualized using a green fluorescent protein marker (gfp encoding GFP). Although the P. borealis strain was originally isolated by ice-affinity, bacterial cultures with membrane-associated INP-GFP did not adsorb to pre-formed ice. Employment of a shuttle vector allowed expression of ina-gfp in both Escherichia coli and Pseudomonas cells. At 27 °C, diffuse fluorescence appeared throughout the cells and was associated with low INA. However, after transfer of cultures to 4 °C, the protein localized to the poles coincident with high INA. Transformants with truncated INP sequences ligated to either gfp, or an antifreeze protein-gfp fusion showed that the repetitive ice-nucleation domain was not necessary for localization. Such localization is consistent with the flanking residues of the INP associating with a temperature-dependent secretion apparatus. A polar location would facilitate INP-INP interactions resulting in the formation of larger aggregates, serving to increase INA. Expression of INPs by P. borealis could function as an efficient atmospheric dispersal mechanism for these soil bacteria, which are less likely to use these proteins for nutrient procurement, as has been suggested for P. syringae. PMID:24930584

  3. Oil palm EgCBF3 conferred stress tolerance in transgenic tomato plants through modulation of the ethylene signaling pathway.

    Science.gov (United States)

    Ebrahimi, Mortaza; Abdullah, Siti Nor Akmar; Abdul Aziz, Maheran; Namasivayam, Parameswari

    2016-09-01

    CBF/DREB1 is a group of transcription factors that are mainly involved in abiotic stress tolerance in plants. They belong to the AP2/ERF superfamily of plant-specific transcription factors. A gene encoding a new member of this group was isolated from ripening oil palm fruit and designated as EgCBF3. The oil palm fruit demonstrates the characteristics of a climacteric fruit like tomato, in which ethylene has a major impact on the ripening process. A transgenic approach was used for functional characterization of the EgCBF3, using tomato as the model plant. The effects of ectopic expression of EgCBF3 were analyzed based on expression profiling of the ethylene biosynthesis-related genes, anti-freeze proteins (AFPs), abiotic stress tolerance and plant growth and development. The EgCBF3 tomatoes demonstrated altered phenotypes compared to the wild type tomatoes. Delayed leaf senescence and flowering, increased chlorophyll content and abnormal flowering were the consequences of overexpression of EgCBF3 in the transgenic tomatoes. The EgCBF3 tomatoes demonstrated enhanced abiotic stress tolerance under in vitro conditions. Further, transcript levels of ethylene biosynthesis-related genes, including three SlACSs and two SlACOs, were altered in the transgenic plants' leaves and roots compared to that in the wild type tomato plant. Among the eight AFPs studied in the wounded leaves of the EgCBF3 tomato plants, transcript levels of SlOSM-L, SlNP24, SlPR5L and SlTSRF1 decreased, while expression of the other four, SlCHI3, SlPR1, SlPR-P2 and SlLAP2, were up-regulated. These findings indicate the possible functions of EgCBF3 in plant growth and development as a regulator of ethylene biosynthesis-related and AFP genes, and as a stimulator of abiotic stress tolerance. PMID:27513726

  4. Performance of heat pumps with direct expansion in vertical ground heat exchangers in heating mode

    International Nuclear Information System (INIS)

    Highlights: • The work focuses on direct expansion ground source heat pumps in heating mode. • The evaporating process of the refrigerant fluid into boreholes is analyzed. • A method to design the direct expansion borehole heat exchangers is presented. • Direct expansion and the common secondary loop heat pumps are compared. • The comparison is carried out in terms of both borehole length and performance. - Abstract: Ground source heat pump systems represent an interesting example of renewable energy technology for heating and cooling of buildings. The connection with the ground is usually done by means of a closed loop where a heat-carrier fluid (pure water or a solution of antifreeze and water) flows and, in heating mode, moves heat from ground to refrigerant fluid of heat pump. A new solution is the direct expansion heat pump. In this case, the heat-carrier fluid inside the ground loop is the same refrigerant fluid of heat pump. This paper focuses on the energy performance of direct expansion ground source heat pump with borehole heat exchangers in heating mode, looking at residential building installations. For this purpose, the evaporating process of the refrigerant fluid inside vertical tubes is investigated in order to analyze the influence of the convective heat transfer coefficient on the global heat transfer with the surrounding ground. Then, an analytical model reported in literature for the design of common borehole heat exchangers has been modified for direct expansion systems. Finally, the direct expansion and common ground source heat pumps have been compared in terms of both total borehole length and thermal performance. Results indicate that the direct expansion system has higher energy performance and requires lower total borehole length compared to the common system. However, when the two systems are compared with the same mean fluid evaporating temperature, the overall length of the ground heat exchanger of the direct expansion heat

  5. Genome reconstructions indicate the partitioning of ecological functions inside a phytoplankton bloom in the Amundsen Sea, Antarctica

    Directory of Open Access Journals (Sweden)

    Tom O Delmont

    2015-10-01

    Full Text Available Antarctica polynyas support intense phytoplankton blooms, impacting their environment by a substantial depletion of inorganic carbon and nutrients. These blooms are dominated by the colony-forming haptophyte Phaeocystis antarctica and they are accompanied by a distinct bacterial population. Yet, the ecological role these bacteria may play in P. antarctica blooms awaits elucidation of their functional gene pool and of the geochemical activities they support. Here, we report on a metagenome (῀160 million reads analysis of the microbial community associated with a P. antarctica bloom event in the Amundsen Sea polynya (West Antarctica. Genomes of the most abundant Bacteroidetes and Proteobacteria populations have been reconstructed and a network analysis indicates a strong functional partitioning of these bacterial taxa. Three of them (SAR92, and members of the Oceanospirillaceae and Cryomorphaceae are found in close association with P. antarctica colonies. Distinct features of their carbohydrate, nitrogen, sulfur and iron metabolisms may serve to support mutualistic relationships with P. antarctica. The SAR92 genome indicates a specialization in the degradation of fatty acids and dimethylsulfoniopropionate (compounds released by P. antarctica into dimethyl sulfide, an aerosol precursor. The Oceanospirillaceae genome carries genes that may enhance algal physiology (cobalamin synthesis. Finally, the Cryomorphaceae genome is enriched in genes that function in cell or colony invasion. A novel pico-eukaryote, Micromonas related genome (19.6 Mb, ~94% completion was also recovered. It contains the gene for an anti-freeze protein, which is lacking in Micromonas at lower latitudes. These draft genomes are representative for abundant microbial taxa across the Southern Ocean surface.

  6. The Pharmacological Properties and Therapeutic Use of Apomorphine

    Directory of Open Access Journals (Sweden)

    Samo Ribarič

    2012-05-01

    Full Text Available Apomorphine (APO is an aporphine derivative used in human and veterinary medicine. APO activates D1, D2S, D2L, D3, D4, and D5 receptors (and is thus classified as a non-selective dopamine agonist, serotonin receptors (5HT1A, 5HT2A, 5HT2B, and 5HT2C, and α-adrenergic receptors (α1B, α1D, α2A, α2B, and α2C. In veterinary medicine, APO is used to induce vomiting in dogs, an important early treatment for some common orally ingested poisons (e.g., anti-freeze or insecticides. In human medicine, it has been used in a variety of treatments ranging from the treatment of addiction (i.e., to heroin, alcohol or cigarettes, for treatment of erectile dysfunction in males and hypoactive sexual desire disorder in females to the treatment of patients with Parkinson's disease (PD. Currently, APO is used in patients with advanced PD, for the treatment of persistent and disabling motor fluctuations which do not respond to levodopa or other dopamine agonists, either on its own or in combination with deep brain stimulation. Recently, a new and potentially important therapeutic role for APO in the treatment of Alzheimer’s disease has been suggested; APO seems to stimulate Ab catabolism in an animal model and cell culture, thus reducing the rate of Ab oligomerisation and consequent neural cell death.

  7. Two cold-induced family 19 glycosyl hydrolases from cherimoya (Annona cherimola) fruit: an antifungal chitinase and a cold-adapted chitinase.

    Science.gov (United States)

    Goñi, Oscar; Sanchez-Ballesta, María T; Merodio, Carmen; Escribano, María I

    2013-11-01

    Two cold-induced chitinases were isolated and purified from the mesocarp cherimoyas (Annona cherimola Mill.) and they were characterised as acidic endochitinases with a Mr of 24.79 and 47.77kDa (AChi24 and AChi48, respectively), both family 19 glycosyl hydrolases. These purified chitinases differed significantly in their biochemical and biophysical properties. While both enzymes had similar optimal acidic pH values, AChi24 was enzymatically active and stable at alkaline pH values, as well as displaying an optimal temperature of 45°C and moderate thermostability. Kinetic studies revealed a great catalytic efficiency of AChi24 for oligomeric and polymeric substrates. Conversely, AChi48 hydrolysis showed positive co-operativity that was associated to a mixture of different functional oligomeric states through weak transient protein interactions. The rise in the AChi48 kcat at increasing enzyme concentrations provided evidence of its oligomerisation. AChi48 chitinase was active and stable in a broad acidic pH range, and while it was relatively labile as temperatures increased, with an optimal temperature of 35°C, it retained about 50% of its maximal activity from 5 to 50°C. Thermodynamic characterisation reflected the high kcat of AChi48 and the remarkably lower ΔH(‡), ΔS(‡) and ΔG(‡) values at 5°C compared to AChi24, indicating that the hydrolytic activity of AChi48 was less thermodependent. In vitro functional studies revealed that AChi24 had a strong antifungal defence potential against Botrytis cinerea, whereas they displayed no cryoprotective or antifreeze activity. Hence, based on biochemical, thermodynamic and functional data, this study demonstrates that two acidic endochitinases are induced at low temperatures in a subtropical fruit, and that one of them acts in an oligomeric cold-adapted manner. PMID:23890591

  8. Winter Low Back Pressure Operation and Economic Analysis of A Certain 600MW Direct Air-cooled Unit%某600MW直接空冷机组冬季低背压运行研究及经济性分析

    Institute of Scientific and Technical Information of China (English)

    朱小东; 王乃军; 胡鑫; 王鹏辉

    2016-01-01

    某600MW发电厂二期机组采用直接空冷方式。直接空冷技术空冷机组进入冬季运行时,鉴于厂家建议,同时迫于空冷岛防冻压力,机组维持较高背压运行,一般维持高于阻塞背压3~5kPa,严重影响机组运行经济性。通过对机组运行现状的调查,分析制约机组冬季低背压运行的原因,并针对具体的原因制定了详细的对策及实施措施。措施实施后,在保证空冷凝汽器安全运行的前提下有效降低了机组冬季运行背压,提高了机组运行经济性。%In view of the factory suggestion and under the antifreezing pressure of air-cooled inland, the air-cooled unit of the two period in Mongolia dai hai power plant needed to maintain a high back pressure while it operated in winter, usurally with 3-5kPa higher than the blocking pressure. This condition affected the economy of unit operation seriously., this paper analysed the causes of restricting the unit operation under low pressure in winter and taked detailed countermeasures and measures to solve specific reasons According to the investigation on unit operation status. It was just the implementation of these measures that reduced the back pressure of unit while running in winter in the precondition of ensuring safe opera-tion of the air-cooled condenser, accordingly improving the economy of unit operation.

  9. The Importance of Temperature and Nitrogen Speciation on Bacterial Diversity in Stream Sediments in the McMurdo Dry Valleys

    Science.gov (United States)

    Baeseman, J. L.; Ward, B. B.

    2006-12-01

    the first step toward understanding the microbial communities in this ecosystem and will provide the foundation for studies on biogeochemical function and microbe survival. These will not only be important for better understanding the dry valleys but will likely give insights into new anti-freeze proteins, desiccation mechanisms and UV-damaged DNA repair strategies which are of societal importance.

  10. Project Profile and Design Keystones Regarding Water Supply and Drainage & Fire Water System for Rolling Stock Depot of Shenyang Metro Line 1%沈阳地铁1号线车辆段给排水、水消防工程布局及设计要点

    Institute of Scientific and Technical Information of China (English)

    陈新; 刘爱芳; 刘学志

    2014-01-01

    根据沈阳地铁1号线车辆段给排水及消防工程的设计施工及运营的实际情况,总结地处严寒及寒冷地区的沈阳地铁车辆段给排水及消防工程的方案确定及设计重点、难点,关键技术与主要创新点,严寒地区车辆段给排水管道设计应充分考虑当地的气候特点和冻土深度等因素,做好设备管道和构筑物的保温防冻措施,水消防系统应按照全段同一时间一处火灾统一考虑,避免重复建设。%Based on actual situation of design, construction and operation of the project regarding water supply and drainage as well as fire extinguishing system for the rolling stock depot of Shenyang Metro Line 1, this paper made a summary on this project which is located at severe cold region and cold region, including the project profile, design keystones and difficulties, key technology, and the main innovation. It is suggested in this paper that: (a) during designing the water supply and drainage pipelines for a rolling stock depot at severe cold region, the local climatic features, the depth of frozen soil and so on should be taken into full account, and also the measures of heat preservation and anti-freezing for both the equipment pipelines and structures should be prepared adequately; (b) the fire water system should be comprehensively considered in accordance with the supposing that there is one fire disaster at the same time in the whole depot, so as to avoid duplicated construction.

  11. Decomposition of indoor ammonia with TiO 2-loaded cotton woven fabrics prepared by different textile finishing methods

    Science.gov (United States)

    Dong, Yongchun; Bai, Zhipeng; Liu, Ruihua; Zhu, Tan

    Addition of urea-based antifreeze admixtures during cement mixing in construction of buildings has led to increasing indoor air pollution due to continuous transformation and emission of urea to gaseous ammonia in indoor concrete wall. In order to control ammonia pollution from indoor concrete wall, the aqueous dispersion was firstly prepared with nano-scale TiO 2 photocatalysts and dispersing agent, and then mixed with some textile additives to establish a treating bath or coating paste. Cotton woven fabrics were used as the support materials owing to their large surface area and large number of hydrophilic groups on their cellulose molecules and finished using padding and coating methods, respectively. Two TiO 2-loaded fabrics were obtained and characterized by X-ray diffractometer (XRD) and scanning electron microscopy (SEM). Moreover, a specifically designed ammonia photocatalytic system consisting of a small environmental chamber and a reactor was used for assessing the performance of these TiO 2-loaded fabrics as the wall cloth or curtains used in house rooms in the future and some factors affecting ammonia decomposition are discussed. Furthermore, a design equation of surface catalytic kinetics was developed for describing the decomposition of ammonia in air stream. The results indicated that increasing dosage of the TiO 2 aqueous dispersion in treating bath or coating paste improved the ammonia decomposition. And ammonia was effectively removed at low ammonia concentration or gas flow rate. When relative humidity level was 45%, ammonia decomposition was remarkably enhanced. It is the fact that ammonia could be significantly decomposed in the presence of the TiO 2-padded cotton fabric. Whereas, the TiO 2-coated cotton fabric had the reduced photocatalytic decomposition of ammonia and high adsorption to ammonia owing to their acrylic binder layer. Finally, the reaction rate constant k and the adsorption equilibrium constant K values were determined through a

  12. Scavenging of ammonia by raindrops in Saturn's great storm clouds

    Science.gov (United States)

    Delitsky, M. L.; Baines, Kevin

    2016-10-01

    Observations of the great Saturn storms of 2010-2011 by Cassini instruments showed a very large depletion in atmospheric ammonia. While dynamics will play a role, the very high solubility of ammonia in water may be another important contributor to ammonia depletion in storms. Ammonia exists in Earth's atmosphere and rainstorms dissolve ammonia to a great degree, leaving almost no NH3 in the atmosphere. Studies by Elperin et al (2011, 2013) show that scavenging of ammonia is greatest as a rainstorm starts and lessens as raindrops fall, tapering off to almost zero by the time the rain reaches the ground (Elperin et al 2009). Ammonia is reaching saturation as it dissolves in the aqueous solution. As concentration increases, NH3 is then converted to aqueous species (NH3)x.(H2O)y (Max and Chapados 2013).Ammonia has the highest solubility in water compared to all other gases in the Saturn atmosphere. The Henry's Law constant for NH3 in water is 60 M/atm at 25 C. For H2S, it is 0.001 M/atm. In Saturn storms, it is "raining UP": As water-laden storm clouds convectively rise, ammonia gas will be scavenged and go into solution to a great degree, whilst all the other gases remain mostly in the gas phase. Aqueous ammonia acts as an antifreeze: if ammonia is dissolved in water cloud droplets to the limit of its solubility, as water droplets rise, they can stay liquid (and continue to scavenge NH3) to well below their normal freezing point of 0 Celsius (273 K). The freezing point for a 30 wt % water-ammonia solution is ~189 K. The pressure level where T = 189 K is at 2.8 bars. The normal freezing point of water occurs at the 9 bar pressure level in Saturn's atmosphere. 2.8 bars occurs at the -51 km altitude (below the 1 bar level). 9 bars is at the -130 km level: a difference of 79 km. A water droplet containing 30 wt% NH3 can move upwards from 9 bars to 2.8 bars (79 km) and still remain liquid, only freezing above that altitude. Calculations by the E-AIM model show that ammonia

  13. Comparative Experimental Research on Concrete Surface Treatment Materials Resistance to Wind Erosion%混凝土抗风蚀磨损表面强化处理材料的对比试验研究

    Institute of Scientific and Technical Information of China (English)

    章岩; 王起才; 张粉芹; 马华军

    2012-01-01

    The second double-track section in Xinjiang of Lanzhou-Xinjiang Railway crosses the five most powerful wind areas of the nine wind areas in Xinjiang. For wind erosion to the railway concrete structure, by means of abrasion resistance and hydrophobicity tests, four kinds of concrete surface treatment materials were chosen to carried through research to improve the abrasion resistance of concrete surface. The results show that four kinds of surface treatment materials can all improve the abrasion resistance of concrete surface to wind erosion. Among which, permeable composite latex concrete surface treatment material has comprehensive advantages in abrasion resistance, hydrophobicity and price. It can penetrate through the surface of concrete by surface seepage method and react with concrete to form a dense hydrophobic net structure on the surface to achieve the effects of protection and resistance to wind erosion. It can improve the abrasion resistance of concrete surface more than doubled, and the surface drying time is reduced 99. 35%. It has better effect in anti-ultraviolet, anti-cracking and anti-freezing, etc.%兰新铁路第二双线新疆段穿越新疆九大风区中风力最强的五大风区.针对风蚀对铁路混凝土结构物的磨蚀问题,选用4种表面强化材料,通过混凝土耐磨蚀和疏水性试验,进行提高混凝土表面耐风蚀性能研究.结果表明:4种表面强化材料均可提高混凝土表面的抗风蚀磨损能力;其中渗透性复合乳液型混凝土表面抗风蚀处理材料在提高混凝土的耐磨蚀性和疏水性以及价格方面具有综合优势,它通过表面渗透方式渗入混凝土中并和混凝土发生反应,在混凝土表面形成致密疏水的网状结构,达到防护和抗风蚀的效果,可提高混凝土表面耐磨度一倍多,表干时间缩短99.35%,且在抗紫外线、抗开裂、抗冻等方面均表现出较好的效果.

  14. 湖南电网220kV线路直流融冰问题研究%Study on problem of DC ice-melting of the Hunan 220 kV power grid

    Institute of Scientific and Technical Information of China (English)

    阮启运; 顾雪平; 陆佳政; 张红先

    2011-01-01

    分析了线路融冰顺序、电源点选择以及短路点选择三个融冰线路问题,根据其解决方法和模拟现场参数利用Matlab搭建仿真模型计算线路融冰电流,并选择性加入谐波抑制电抗控制谐波畸变率.利用VFP开发了一套存储查询线路电气参数以及计算融冰时间的防冻融冰管理系统,并根据其计算结果分析了融冰时间与覆冰厚度、融冰电流、风速、气温之间的关系.在娄底220 kV田上线上,采用移动式直流融冰装置,搭建仿真模型计算融冰电流和分析其谐波影响,并通过管理系统计算融冰时间,计算结果与现场融冰的结果基本吻合.%The paper analyzes three line ice-melting problems, including the line sequence of melting ice, power point selection, and short-circuit point selection.According to the solving methods and the simulated parameters, the simulation models to calculate the ice-melting current are built on Matlab, and harmonic suppression reactance is added selectively to contol harmonic distortion.VFP is used to develop a management system of anti-freezing and ice-melting, which can store and inquire line electrical parameters and calculate ice-melting time.Based on the calculating results, the relations between the ice-melting time and the ice thickness, ice-melting current, the wind speed, and the temperature are analyzed.The moving DC ice-melting device is used on 220 kV Tian-Shang line in Loudi.By building simulation models, the ice-melting current is obtained and the harmonics' influence is analyzed, then the ice-melting time is computed by the management system.It's shown that the calculation results basically accord with the results on the spot.

  15. Hydrothermal Habitats: Measurements of Bulk Microbial Elemental Composition, and Models of Hydrothermal Influences on the Evolution of Dwarf Planets

    Science.gov (United States)

    Neveu, Marc Francois Laurent

    Finding habitable worlds is a key driver of solar system exploration. Many solar system missions seek environments providing liquid water, energy, and nutrients, the three ingredients necessary to sustain life. Such environments include hydrothermal systems, spatially-confined systems where hot aqueous fluid circulates through rock by convection. I sought to characterize hydrothermal microbial communities, collected in hot spring sediments and mats at Yellowstone National Park, USA, by measuring their bulk elemental composition. To do so, one must minimize the contribution of non-biological material to the samples analyzed. I demonstrate that this can be achieved using a separation method that takes advantage of the density contrast between cells and sediment and preserves cellular elemental contents. Using this method, I show that in spite of the tremendous physical, chemical, and taxonomic diversity of Yellowstone hot springs, the composition of microorganisms there is surprisingly ordinary. This suggests the existence of a stoichiometric envelope common to all life as we know it. Thus, future planetary investigations could use elemental fingerprints to assess the astrobiological potential of hydrothermal settings beyond Earth. Indeed, hydrothermal activity may be widespread in the solar system. Most solar system worlds larger than 200 km in radius are dwarf planets, likely composed of an icy, cometary mantle surrounding a rocky, chondritic core. I enhance a dwarf planet evolution code, including the effects of core fracturing and hydrothermal circulation, to demonstrate that dwarf planets likely have undergone extensive water-rock interaction. This supports observations of aqueous products on their surfaces. I simulate the alteration of chondritic rock by pure water or cometary fluid to show that aqueous alteration feeds back on geophysical evolution: it modifies the fluid antifreeze content, affecting its persistence over geological timescales; and the

  16. Performance Evaluation of Liquid Catalysts for Removal of Mercaptan%液体脱硫醇催化剂的性能评价

    Institute of Scientific and Technical Information of China (English)

    江胜娟; 孙小明; 张桅; 周玉路; 项玉芝; 夏道宏

    2012-01-01

    以氯磺酸与酞菁钴为原料合成多磺化酞菁钴,制得活性组分含量为23.8%(w)的液体脱硫醇催化剂(Cat.A).采用硫含量、动态光散射及电位滴定等方法考察了Cat.A的结构、粒径分布及催化氧化性能,并与进口和国产液体脱硫醇催化剂进行比较.实验结果表明,Cat.A的磺化酞菁钴中平均磺酸取代基个数为3.4;Cat.A在碱液中具有较好的分散性、溶解性和较高的稳定性;在Cat.A质量浓度为100 μtg/g、Cat.A用量3 mL、汽油(混合硫醇硫含量为255 μg/g)体积30 mL、反应温度30 ℃、反应时间30 min的条件下,Cat.A对汽油中硫醇的脱除率达90%,其脱硫醇活性与进口液体脱硫醇催化剂的活性相当.%Multi-sulfonated cobalt phthalocyanine was synthesized by the reaction of cobalt phthalocynine with chlorosulfonic acid, and then a liquid catalyst(Cat.A) with 23.8%(w) of the multi-sulfonated cobalt phthalocyanine as the active component for the removal of mercaptans from gasoline was prepared by dissolving the active component in sodium hydroxide solution with a stabilizer and an antifreezer. Cat.A was characterized by sulfur content analysis, dynamic light scattering analysis and potentiometric titration to investigate its structure, size distribution and catalytic activity, and compared with imported and domestic liquid desulfurization catalysts. The experimental results show that the average sulfonic group number in the every multi-sulfonated cobalt phthalocyanine molecule in Cat.A is 3.4. The active component in the alkali solution has good dispersity, solubility and stability. The removal rate of the mercaptans in gasoline could reach 90% using Cat.A under the conditions of the catalyst mass concentration 100 μg/g, the catalyst dosage 3 mL, gasoline with 255 μg/g of mercaptan sulfur mass concentration 30 mL, reaction temperature 30 ℃. and reaction time 30 min.

  17. Phase behaviour and thermoelastic properties of ammonia hydrate and ice polymorphs from 0 - 2 GPa

    Science.gov (United States)

    Fortes, A. D.; Wood, I. G.; Vocadlo, L.

    2008-12-01

    Ammonia remains amongst the most plausible planetary "antifreeze" agents, and its physical properties in hydrate compounds under the appropriate conditions (roughly 0 - 5 GPa, 100 - 300 K) must be known in order for it to be accommodated in planetary models. The pressure melting curve, and the expected polymorphism of the stoichiometric ammonia hydrates have implications for the internal structure of large icy moons like Titan, leading to phase layering and the possible persistence of deep subsurface oceans, the latter being sites of high astrobiological potential. Aqueous ammonia is also a candidate substance involved in cryomagmatism on Titan, and again the melting behaviour, and densities of liquids and solids, in the ammonia-water system must be known to model properly the partial melting and propagation of magma. We describe the results of a series of powder neutron diffraction experiments over the range 0 - 2.0 GPa, 150 - 280 K which were carried out with the objective of determining the phase behaviour and thermoelastic properties of ammonia dihydrate. In addition to the low-pressure cubic crystalline phase, ADH I, we have identified two closely related monoclinic polymorphs of ammonia dihydrate (ADH IIa and IIb) in the range 0.45 - 0.60 GPa (at 175 K), and have determined that this phase dissociates to a mixture of ammonia monohydrate phase II and ice II when warmed to ~190 K, which in turn melts at a binary eutectic at ~196 K; AMH II has a large (Z = 16) orthorhombic unit cell. Above 0.60 GPa, an orthorhombic polymorph of ammonia dihydrate, which we have referred to previously as ADH IV, persists to pressures > 3 GPa, and appears to be the liquidus phase over this whole pressure range. We have observed this phase co- existing with both ice II and ice VI. Here we describe the most plausible synthesis of the high-pressure phase diagram which explains our observations, and provide measurements of the densities, thermal expansion, bulk moduli, and crystal

  18. Silicon Utilizing Microbial Bioactivities in the Biosphere

    Science.gov (United States)

    Sen, M. M.; Das, S.

    2012-12-01

    Diatoms are unicellular eukaryotic algae and an important member of the silicon utilizing organisms, that generate ~20% of the ~100 billion metric tons of organic carbon produced through photosynthesis on Earth each year. Fragilariopsis is a dominating psychrophilic diatom genus in polar sea ice. The two species Fragilariopsis cylindrus and Fragilariopsis curta are able to grow and divide below freezing temperature. Antifreeze proteins (AFPs), involved in cold adaptation in several psychrophilic organisms, are widespread in this two polar species. Achanthes minutissima isolated as dominant diatom has degradable effects involving petroleum hydocarbons. Phaeodactylum tricornutum, have antibacterial activity and the fatty acid, eicosapentaenoic acid (EPA), has been identified as one compound responsible for this activity. Other antibacterial compounds are monounsaturated fatty acid (9Z)-hexadecenoic acid (palmitoleic acid; C16:1 n-7) and the relatively unusual polyunsaturated fatty acid (6Z, 9Z, 12Z)-hexadecatrienoic acid (HTA; C16:3 n-4). Both are active against Gram-positive bacteria and many Gram-negative pathogen. Palmitoleic acid is active at micro-molar concentrations, kills bacteria rapidly, and is highly active against multidrug-resistant Staphylococcus aureus. Domoic acid -a neurotoxin produced by Pseudo-nitzschia accumulates in marine invertebrates. Evidences of sea lion (Zalophus californianus) and human poisoning following consumption of contaminated blue mussels (Mytilus edulis) is mainly due to this toxin. Among the most prominent features described in human beings was memory impairment which led to the name Amnesic Shellfish Poisoning [ASP]. Silicon utilizing organisms can act as a bioindicator of environmental contamination, thus a rapid change in phytochelatins to both the increase in and the withdrawal of environmental Cd stress was found in Thalassiosira nordenskioeldii. Some of them also can produce biofuels particularly diatoms have significant

  19. Development of PLC based chiller control system for 3 MeV DC electron beam accelerator

    International Nuclear Information System (INIS)

    A 3 MeV DC electron beam accelerator is under development at Electron beam center, Kharghar, Navi Mumbai. The accelerator has various sections, where heat is generated during operation due to factors contributed by efficiency. The areas that produce heat such as beam dump, HV oscillator, scan horn region etc need to be cooled. A 5TR chiller unit has been installed in a room in the vicinity of the accelerator. Standard chiller unit available in the market do not provide a remote control interface, instead they provide on panel local controllers for the operation of the system. A PLC based interlock has been developed to control all the chiller components such as Cooling tower fan, cooling tower pump, ON/OFF operation of compressor etc. All the components used in chiller unit are interfaced to PLC besides temperature sensor. All machine safety interlock have been introduced by using suitable hardware such as antifreeze coil used to trip compressor in case of control failure may make the ice of water being cooled. The operating point of the chiller has been set to provide water 22-24 degree C. The PLC has been programmed using ladder logic programming method. The system is fully automatic. The system can be operated by setting the set temperature say 22 degree C and temperature hysteresis say 2 degree C. Pressing start button operates different units of the system automatically. Its starts the compressor when the water temperature is 22+2 degree C and stops the compressor when temp reaches at 22 degree C. Any unexpected failure such as 3Phase sequence change/phase failure, over load relay trip, excess temp are indicated by a hooter sound along with fault display on the HMI. A touch screen panel has been provided for human machine interface. This development of control system for chiller sub-system of accelerator has helped us in bringing the chiller unit control from the control room using Ethernet link using Modbus TCP-IP. The implementation of PLC controlled chiller

  20. 江苏省白沙枇杷优质丰产栽培技术%Cultivation Techniques for Perfect Quality and High Yield of White Flesh Loquat in Jiangsu Province

    Institute of Scientific and Technical Information of China (English)

    袁卫明; 杨益花; 王化坤; 张凯

    2014-01-01

    白沙枇杷以优良的品质而被冠为枇杷中的精品,江苏省是我国白沙枇杷主产区之一。根据多年的生产实践,总结了江苏地区白沙枇杷丰产优质栽培管理技术,主要包括选择良种,合理建园与定植;科学矮化整形,培养早丰产树冠;按需平衡施肥,合理排灌水分;生草与覆盖相结合,有效管理土壤;合理修剪,促进矮化丰产;精细疏花疏果,保障果实质量;适时合理套袋,提高果实商品性;多方措施,有效防冻;无公害综合防治病虫害;适时采收与保鲜,以期为促进江苏省白沙枇杷产量、品质和效益的提高及扩大生产提供技术支持。%White flesh loquat is renowned as elite loquat because of its good quality.Jiangsu is one of the main production areas in China.Through many years production practice,this paper summarized the ten key techniques for high yield and perfect quality cultivation of white flesh loquat in Jiangsu Province,which included selection of improved variety and reasonable orchard establishment,scientific dwarf shaping for training early and high yield fruit tree,balanced fertilization according to need,reasonable drainage and irrigation,efficient soil management by growing grass with coverage,reasonable pruning for promoting dwarf and high yield,fine thinning flowers and fruits for improving fruit quality,suitable fruit bagging for improving fruit commercial quality,efficient antifreeze by many measures,non-pollution integrated control diseases and pests,timely harvesting and fresh-keeping.The paper’s intention was to provide technical support for enhancing fruit yield,quality and profit,extending produce area of white flesh loquat in Jiangsu Province.

  1. Prediction of mineral scale formation in wet gas condensate pipelines and in MEG (mono ethylene glycol) regeneration plants

    Energy Technology Data Exchange (ETDEWEB)

    Sandengen, Kristian

    2006-12-20

    Gas hydrate formation is a serious problem in the oil and gas industry, since its formation can plug wells and prevent production. The gas hydrate is a crystalline solid with a natural gas molecule surrounded by a cage of water molecules. It forms at high pressures and low temperatures. This is a problem for offshore gas wells, where the temperature is low in transport lines from well to the production facilities. Mono Ethylene Glycol (MEG) is commonly used as hydrate inhibitor. Classified as a thermodynamic inhibitor, this additive functions just as antifreeze in an automotive radiator. When producing oil and gas there will in most cases also be produced some water, which can contain dissolved salts. These salts may precipitate and they tend to deposit on surfaces. Deposition of inorganic minerals from brine is called scale. Generally MEG has the adverse effect of lowering the solubility of most salts. A common method to prevent corrosion in flow lines is to increase pH by adding basic agents (e.g. NaOH, NaHCO{sub 3}) to the MEG stream. In such cases, carbonate salts are particularly troublesome since an increase in pH by one unit, will reduce the solubility by two orders of magnitude. Thus there will be a trade off between good corrosion protection (high pH) and scale control (low pH). The aim of this work has been to develop a model that can predict mineral solubility in the presence of MEG. Experimental solubility data, together with thermodynamic data taken from literature, have been utilized to construct empirical functions for the influence of MEG on mineral scale formation. These functions enabled the expansion of an already existing aqueous scale model into a model valid for water+MEG mixed solutions. The aqueous scale model combines an equation of state (gas+oil phase) with the Pitzer ion interaction model (water phase) to describe the multiphase behaviour of gas-oil-water systems. This work summarizes the theoretical foundation and proposes how to work

  2. Analysis of East Main Canal Lining Plan of Qingtongxia Hedong Irrigation Area%青铜峡河东灌区东干渠渠道衬砌方案分析

    Institute of Scientific and Technical Information of China (English)

    张建斌; 陆立国; 唐华

    2014-01-01

    近年来青铜峡河东灌区东干渠灌域引水量不断增大,引发了诸多问题,加快东干渠灌域的节水改造进程势在必行。结合东干渠银平公路桥至吴白公路桥段渠道实际状况,在衬砌改造中考虑了冻胀、边坡滑塌、地下水位高等多种不利因素,采取土工膜防渗,现浇混凝土弧形坡脚、聚苯乙烯板、坡脚铺设排水暗管等防冻胀措施,采取格宾石笼排除渠道基土内的水分、消除流沙段边坡滑塌的排水措施。并通过方案比选,提出了具体衬砌方案。%In recent years due to the increase of diversion volume of east main canal irrigation area,it has caused many problems. To speed up the process of the east main canal irrigation water-saving transformation domain has been imperative. It combined with the actual situation of the section from Ying-Ping Highway Bridge to Wu-Bai Highway Bridge of east main canal and made full use of“preliminary research results,the Ministry of Water Resources in 2013 public industry special fund project of Ningxia Yellow River Diversion Canal Irrigation Area”key technologies research of water distribution in the lining,transformation,the frost heave,slope collapse,high underground water level of various unfavorable factors,adopt-ed geomembrane,cast-in-place concrete arc slope,polystyrene board,the foot laying drainage pipe anti-freezing measures,took the gabion material removal channel soil's moisture,eliminated the drainage measures of slope slide quicksand and scheme selection through comprehensive analysis, the lining. At the same time,it made specific requirements for the main technical indexes of the lining of canals.

  3. Analysis of East Main Canal Lining Plan of Qingtongxia Hedong Irrigation Area%青铜峡河东灌区东干渠渠道衬砌方案分析

    Institute of Scientific and Technical Information of China (English)

    张建斌; 陆立国; 唐华

    2014-01-01

    In recent years due to the increase of diversion volume of east main canal irrigation area,it has caused many problems. To speed up the process of the east main canal irrigation water-saving transformation domain has been imperative. It combined with the actual situation of the section from Ying-Ping Highway Bridge to Wu-Bai Highway Bridge of east main canal and made full use of“preliminary research results,the Ministry of Water Resources in 2013 public industry special fund project of Ningxia Yellow River Diversion Canal Irrigation Area”key technologies research of water distribution in the lining,transformation,the frost heave,slope collapse,high underground water level of various unfavorable factors,adopt-ed geomembrane,cast-in-place concrete arc slope,polystyrene board,the foot laying drainage pipe anti-freezing measures,took the gabion material removal channel soil's moisture,eliminated the drainage measures of slope slide quicksand and scheme selection through comprehensive analysis, the lining. At the same time,it made specific requirements for the main technical indexes of the lining of canals.%近年来青铜峡河东灌区东干渠灌域引水量不断增大,引发了诸多问题,加快东干渠灌域的节水改造进程势在必行。结合东干渠银平公路桥至吴白公路桥段渠道实际状况,在衬砌改造中考虑了冻胀、边坡滑塌、地下水位高等多种不利因素,采取土工膜防渗,现浇混凝土弧形坡脚、聚苯乙烯板、坡脚铺设排水暗管等防冻胀措施,采取格宾石笼排除渠道基土内的水分、消除流沙段边坡滑塌的排水措施。并通过方案比选,提出了具体衬砌方案。

  4. Wintertime Emissions from Produced Water Ponds

    Science.gov (United States)

    Evans, J.; Lyman, S.; Mansfield, M. L.

    2013-12-01

    surfaces. These compounds are highly reactive and, because of their relatively high water solubility, tend to concentrate in produced water. The average methanol emission rate from unfrozen pond surfaces was more than 100 mg m-2 h-1. Methanol, used as an antifreeze and anti-scaler in the oil and gas industry, is abundant during winter inversions in the Uintah Basin and may also be a significant precursor to ozone production. Total VOC and methanol emissions from produced water ponds during winter were estimated to be 178 and 83 tons month-1, respectively, for the entire Uintah Basin.

  5. Optimization of algae carbohydrate compound additives for cyroprotectant on response surface methodology%响应面法优化无磷复合抗冻剂研究

    Institute of Scientific and Technical Information of China (English)

    马路凯; 张宾; 王晓玲; 邓尚贵; 谢超; 朱冬丽

    2015-01-01

    Objective To evaluate the effects of antifreeze and water-holding capacity of trehalose, alginate oligosaccharides, sodium lactate and sodium citrateon the water retention and frost resistance of shrimp. Methods Shrimp (Litopenaeus vannamei)were beheaded and peeled, but not deveined. The peeled shrimp were immediately submerged in the different prepared solutions, then the solutions were wiped onto the surface, and weighted then immersion weight gain rate. Subsequently, these shrimp were frozen in a freezer at-18 ℃ for 4 d, before analysis, and frozen samples were thawed for 3 h in a refrigerator (4 ℃). The thawing loss of frozen shrimp was tested immediately after thawing. Experimental factors and their levels were determined by one-factor tests. Whereafter, the Box-Behnken experimental designed with 4 factors and 3 levels was performed, and the factors influencing the immersion weight gain rate and defrosting loss rate were estimated by means of regression analysis. Results The optimum scheme of compound additives was obtained, which the trehalose mass concentration was 0.8%, the alginate oligosaccharide mass concentration was 0.8%, the sodium lactate mass concentration was 0.7%, the sodium citrate mass concentration was 1.2%, the immersion weight gain rate was 14.62%, and the defrosting loss rate was 2.41%, which were almost accorded with the predicted data. Conclusion The results indicate that the optimum scheme of compound additives has a better anti-freeze activity, compared with the shrimp treated by distilled water (the immersion weight gain rate is 5.27%, the thawing loss rate is 9.05%). The study can lay the foundation for developing a kind of safe, natural and harmless non-phosphate additives for frozen shrimp.%目的:研究无磷复合抗冻剂海藻糖、海藻胶寡糖、乳酸钠及柠檬酸钠等对南美白对虾虾仁保水和抗冻性能的影响。方法将南美白对虾虾仁浸泡在不同溶液中,取出擦干

  6. Producing Light Oil from a Frozen Reservoir: Reservoir and Fluid Characterization of Umiat Field, National Petroleum Reserve, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Hanks, Catherine

    2012-12-31

    with deionized water and less reduction when saturated with saline water. This reduction in relative permeability can be explained by formation of ice crystals in the center of pores. Theoretically, the radius of ice formed in the center of the pore can be determined using the Kozeny–Carman Equation by assuming the pores and pore throats as a cube with ‘N’ identical parallel pipes embedded in it. Using the values of kro obtained from the experimental work as input to the Kozeny–Carman Equation at -10ºC, the radius of ice crystals dropped from 0.145 μm to 0.069 μm when flooding-water salinity is increased to 6467 ppm. This explains the reduction of relative permeability with decreasing salinity but does not take into consideration other effects such as variations in pore throat structure. In addition, fluids like deionized water, saline water, and antifreeze (a mixture of 60% ethylene or propylene glycol with 40% water) were tested to find the best flooding agent for frozen reservoirs. At 0ºC, 9% greater recovery was observed with antifreeze was used as a flooding agent as compared to using saline water. Antifreeze showed 48% recovery even at -10ºC, at which temperature the rest of the fluids failed to increase production. Preliminary evaluation of drilling fluids indicate that the brine-based muds caused significantly less swelling in the Umiat reservoir sands when compared to fresh-water based muds. However since freezing filtrate is another cause of formation damage, a simple water-based-mud may not a viable option. It is recommended that new fluids be tested, including different salts, brines, polymers and oil-based fluids. These fluids should be tested at low temperatures in order to determine the potential for formation damage, the fluid properties under these conditions and to ensure that the freezing point is below that of the reservoir. In order to reduce the surface footprint while accessing the maximum amount of the Lower Grandstand interval

  7. Changes in polyamine content are related to low temperature resistance in potato plants Los cambios en el contenido de poliaminas estan relacionados con la resistencia a temperaturas bajas en plantas de papa

    Directory of Open Access Journals (Sweden)

    Posada Catalina

    1999-11-01

    Full Text Available

    Polyamine content and variation within a 48 hour simulated freezing stress were determined in plants with different low temperature resistance. Genotypes Solanum acaule, Solanum phureja, transgenic Solanum tuberosum c.v. Desiree with antifreezing trans-genes from Winter Flounder and the clone 88-35-7 (tbr- (atzimba x (acl x phu ccc8l were used for the experiment. Tolerant species 5. acaule was the only one that survived freezing stress (80% surviving tissue the others had more than 50% of dead tissue by the end of the experiment. Clone 88-35-7 died slower than S. phureja and transgenic plants of Desiree. This response was related to free putrescine and free spermidine titters of 5. acaule plants and in less extend in clone 88-35-7 plants. Polyamine concentration was low and stable in sensitive plants (5. phureja and Desiree within freezing condition. Soluble bound forms ofpolyamines were the source for Put and Spm increase in 5. acaule and 88-35-7 plants. As a result, soluble bound polyamine titer decreased with the freezing stress.

    En plantas de Solanum acaule, Solanum phureja, Solanum tuberosum c.v. Desireé, transformada con un gen que codifica para proteínas anticongelantes del pez lenguado del Ártico, y el clon 88-35-7 de genealogía (tbr-(atzimba x (ad x phu ccc81, genotipos de papa con diferente grado de tolerancia a las temperaturas bajas, se determinó la variación en el contenido de poliaminas (PA durante una helada simulada en fitorrón. La especie tolerante (5. acaule fue la única que sobrevivió al tratamiento de temperaturas bajas (80% de tejido vivo, las demás especies tuvieron más de un 50% de muerte del tejido al final del experimento. El clon 88-35-7 tuvo una muerte de los tejidos más lenta que S. phureja y que Desireé. La supervivencia de los tejidos estuvo relacionada con los incrementos de los niveles de putrescina (Put y espermina (Spm libres observados en S. acaule y en menor medida en el clon. Los valores

  8. Biodiversity and cold adaptive mechanisms of psychrophiles%低温细菌与古菌的生物多样性及其冷适应机制

    Institute of Scientific and Technical Information of China (English)

    辛玉华; 周宇光; 东秀珠

    2013-01-01

    Cold-adapted bacteria and archaea are widely distributed in cold environments on Earth,such as permafrost,cold soils and deserts,glaciers,lakes,sea ice in the Arctic,Antarctic and high mountains,as well as the deep sea,ice caves and the atmospheric stratosphere etc.Cold-adapted organisms inhabiting these environments exhibit rich diversity.Studies on the biogeography of psychrophiles will enable us to understand their biodiversity,distribution and origins.Due to long-term living in cold regions,cold-adapted bacteria and archeae have developed specific physiological mechanisms of adaptation to cold environments.These mechanisms include:regulating the fluidity of the cytoplasmic membrane through adjusting the composition of membrane lipids; achieving low-temperature protection through compatibility solute,antifreeze proteins,ice-binding proteins,ice-nucleation proteins and anti-nucleating proteins; production of heat-shock and coldshock proteins,cold acclimation protein and DEAD-box RNA helicase at low temperatures; production of cold-active enzymes; increasing energy generation and conservation.With the rapid development of sequencing technology,various omics-based approaches have been used to reveal cold-adaptive mechanisms of psychrophiles at the genomic level.%低温细菌与古菌广泛分布于地球的低温环境,包括南极、北极及高山地带的冻土、低温土壤和荒漠、冰川、湖泊、海冰,以及深海、冰洞和大气平流层等.栖息在这些低温环境中的细菌与古菌具有丰富的多样性,主要为α,p和γ-Proteobacteria分支、CFB类群分支和革兰氏阳性细菌分支等.由于低温环境中的微生物流动性低,因而是研究微生物地理学理想的生态系统,有助于理解地球微生物的多样性、分布规律乃至形成机制.由于长期生活在冰冻环境中,低温细菌与古菌形成了多种适应低温环境的生理机制,如它们通过细胞膜脂类的组成来调节膜的流动性以维

  9. 检材采集与保存方式对DNA提取效率的影响%Effect of Sample Collection and Preservation on DNA Yield

    Institute of Scientific and Technical Information of China (English)

    邓淑娇; 李萍; 黄桂清; 杨电

    2015-01-01

    ABSTRACT:ObjectiveTo explore the effect of sample collection and preservation on DNA yield.MethodsThe fresh anti-freezing blood from 30 volunteers was respectively dropped onto a swab from the casing for collection and preservation of biological sample, and the ones of both the cuspidal and the common medical. Each of the blood specimens was separately preserved in the casing or paper bags for a week. Every piece of DNA from the blood specimens was extracted by magnetic beads method in combination of automation workstation and was quantiifed by ABI 7500 Real Time System.ResultsThe average DNA concentration was (2.54±0.63) ng/μL for the blood specimens collected and preserved with the casings, (2.06±0.44) ng/μL and (0.93±0.59) ng/μL for those blood specimens which were collected with cuspidal swabs and common medical ones and followed to preserve in paper bags. The DNA yield was obviously higher using the casings than that of either the cuspidal swabs or the common medical ones to collect and then preserve in paper bags.ConclusionsThis test suggests that it is better to choose the casings for collection and preservation of biological sample than the cuspidal and the common medical swab.%目的:研究检材采集与保存方式对DNA提取效率的影响。方法使用生物检材采集与保存套管棉签、尖头棉签和普通医用棉签采集血样,分别放置于生物检材采集与保存套管或纸质物证袋中保存1周。剪取全部血样于96孔板中,用磁珠法结合自动化工作站提取DNA,以ABI7500型荧光定量PCR仪定量。结果生物检材采集与保存套管采集保存的血样所提取的DNA浓度平均为(2.54±0.63)ng/μL ,而尖头棉签、普通医用棉签采集并分别用纸袋保存的血样提取的DNA浓度平均为(2.06±0.44)ng/μL和(0.93±0.59) ng/μL。结论生物检材采集与保存套管较之于尖头棉签或普通医用棉签采集、纸袋保存方式,其获得的DNA浓度显著提高,DNA提取率高。

  10. 冻融作用对膨润土防渗毯防渗特性的影响%Effect of freeze-thaw action on geosynthetic clay liner anti-seepage characteristics

    Institute of Scientific and Technical Information of China (English)

    周春生; 史海滨; 于健

    2012-01-01

    为研究膨润土防渗毯(Geosynthetic Clay Liner)在寒旱区渠道衬砌应用中的防渗性能,该文采用室内模拟方法对3种膨润土防渗毯(分别为韩国、中国生产,编号为1#、2#、3#)的抗冻特性进行了研究,结果表明:采用黄河水水化31次冻融后,1#、2#、3#膨润土防渗毯自由膨胀体积增加了16.7%、4.5%、8.0%,滤失量降低了31.1%、28.9%、27.0%,屈服值增加了200.0%、23.3%、90.6%.31次冻融循环后滤出液EC值分别降低27.3%、27.0%、31.0%,渗透系数均增加了1个数量级,但渗透系数仍较小,仅为渠床土壤渗透系数的0.35%~0.72%;研究表明,膨润土防渗毯可用于西北干旱盐渍化地区渠道衬砌.%In order to study the seepage control performance of Geosynthetic Clay Liner (GCL) in lining channel in the cold and arid regions, the antifreeze characteristics of three different GCL (produced in Korea and China, 1#、 2#、 3#) were studied with indoor simulation method. The results showed that by hydrating with the Yellow River water and after 31 times of freeze-thaws , the free swelling volume of 1#、 2#、 3# GCL increased by 16.7%> 4.5% and 8.0% respectively; The filtration loss reduced by 31.1%, 28.9% and 27.0% respectively; The yield value increased by 200.0%, 23.3% and 90.6% respectively, and the EC values of the filtrate reduced by 27.3%, 27.0% and 31.0% respectively. The permeability coefficient increased by one order of magnitude, but was still small, which was 0.35-0.72% in canal bed. These indicated the GCL can be used in canal lining in the northwest arid and saline regions.

  11. Research Progress in the Preparation Methods and Applications of the Superhydrophobic Surface for Metal Protection%金属防护用超疏水表面主要制备方法及应用研究进展

    Institute of Scientific and Technical Information of China (English)

    赵欢; 吕晓璇; 周圣文; 方亮; 王力

    2015-01-01

    金属及其合金制品的腐蚀给人类带来巨大危害. 主要从金属表面超疏水的角度探究金属的防护,在介绍超疏水表面相关理论的基础上,详细综述了国内外金属基体超疏水表面的最新研究进展和应用,讨论了化学腐蚀法、激光毛化技术、喷涂法、电化学技术、水热法、等离子体处理技术、置换沉积法、溶液浸泡法、复合法等超疏水表面制备技术的研究进展,这些技术都在一定程度上实现了金属表面超疏水性能,接触角达到150 °以上,滚动角小于10 °. 除此之外,还介绍了超疏水表面在装饰金属材料、耐腐蚀、自清洁、防结冰、抗菌等方面的应用. 最后指出了金属基体超疏水表面制备在工业应用中存在的缺陷,并对今后的发展方向进行了展望.%The corrosion of metals and their alloys has caused great harm to mankind. In this paper, we explored the protection of metals from the point of superhydrophobic metal surface. On the basis of the theory about superhydrophobic surface, the latest research progress and application of superhydrophobic surface on metal substrates were reviewed. Research progresses in prepara-tion methods of superhydrophobic surface such as chemical etching, laser texturing, spraying, electrochemical, hydrothermal, plasma treatment, replacement deposition, solution immersion and composite were discussed in detail. These methods mentioned above have achieved the superhydrophobic properties of the metals to a certain degree with the contact angle of more than 150 de-gree and sliding angle of less than 10 degree. Furthermore, this paper also introduced the applications of the superhydrophobic sur-face in decorating metal materials, corrosion resistance, self-cleaning, anti-freezing and anti-bacteria. At the end of the paper, the existing defects of superhydrophobic metal surface preparation in industrial application were pointed out, and the development di-rection in the

  12. 构建结球甘蓝K IN基因在叶绿体基因组定点表达的载体%Construction of Chloroplast Site-specific Integration Expression Vector Harboring KIN Gene of Cabbage (Brassica oleracea L. var. capitata L.)

    Institute of Scientific and Technical Information of China (English)

    陶鹏; 黄小云; 李必元; 王五宏; 岳智臣; 雷娟利; 钟新民

    2015-01-01

    获得叶绿体基因组定点整合表达载体是开展结球甘蓝叶绿体基因组的遗传转化研究的第一步。本研究克隆了CMS结球甘蓝的抗冻蛋白K IN基因,发现该基因定位于结球甘蓝的2号染色体上。通过构建中间载体pKA和pAI,将K IN基因的编码区构建到了CMS结球甘蓝叶绿体基因组定点整合表达载体pIKAA中。该载体以TrnA 和TrnI基因片段作为同源整合片段,能整合到CMS结球甘蓝叶绿体基因组中。此外,该载体是双顺反子形式的,即在转录的单条mRNA上,同时包含了K IN和aadA 基因编码区。将pIKAA转化到大肠杆菌中,结果显示转化有该载体的大肠杆菌能够在含有氨苄青霉素(AMP)和壮观霉素(SPEC)的固体LB平板中生长。研究结果可为后期CMS结球甘蓝叶绿体基因组的遗传转化体系的建立奠定基础。%To construct chloroplast site-specific integration expression vector is the first step for carrying on genetic transformation of cabbage chloroplast genome (Brassica oleracea L. var. capitata L.). In this study, antifree-ze protein KIN gene was cloned from cytoplasmic male sterility (CMS) cabbage (Brassica oleracea L. var. capitata L.), and was located in 2 chromosome in B. oleracea genome. By constructing the intermediate vector pKA and pAI, coding region of KIN gene was inserted into the site-specific integration expression vector (pIKAA) of CMS cabbage chloroplast. Due to the fragments of TrnA and TrnI used as homologous integration fragments, the pIKAA could target to chloroplast genomes of CMS cabbage. In addition, the pIKAA vector was bicistronic. The single transcribed mRNA from the pIKAA vector contained simultaneously coding regions of KIN and aadA gene. The vector was transformed into E. coli that can grow in LB containing ampicillin and spectinomycin. The study might lay essential basis in establishment of genetic transformation system of chloroplast genome of CMS cabbage.

  13. Emergence of Habitable Environments in Icy World Interiors

    Science.gov (United States)

    Neveu, Marc

    2016-07-01

    Finding habitable worlds is a key driver of solar system exploration. Many solar system missions seek environments providing liquid water, energy, and nutrients, the three ingredients necessary to sustain life [1]. Such environments include hydrothermal systems, spatially confined systems where hot aqueous fluid circulates through rock by convection. Hydrothermal activity may be widespread in the solar system. Most solar system worlds larger than 200 km in radius are icy moons and dwarf planets, likely composed of an icy, cometary mantle surrounding a rocky, chondritic core [2]. By improving an icy world evolution code [3] to include the effects of core fracturing and hydrothermal circulation, I show that several icy moons and dwarf planets likely have undergone extensive water-rock interaction [4,5]. This supports observations of aqueous products on their surfaces [6,7]. I simulated the alteration of chondritic rock [8] by pure water or fluid of cometary composition [9] to show that aqueous alteration feeds back on geophysical evolution: it modifies the fluid antifreeze content, affecting its persistence over geological timescales; and the distribution of radionuclides, whose decay is a chief heat source on dwarf planets [10]. Hydrothermal circulation also efficiently transports heat from the core into the ocean, thereby increasing ocean persistence [4]. Thus, these coupled geophysical-geochemical models provide a comprehensive picture of icy world evolution and the emergence of liquid environments in chemical disequilibrium with underlying rock in their interiors. Habitable settings also require a suitable supply of bioessential elements; but what constitutes "suitable"? I sought to quantify the bulk elemental composition of hydrothermal microbial communities, collected in hot spring sediments and mats at Yellowstone National Park, USA. To do so, one must minimize the contribution of non-biological material to the samples analyzed. This was achieved using a

  14. 30%乙氧氟草醚·乙草胺水乳剂的研制%Study on the Formulation of 30% Oxyfluorfen and Acetochlor EW

    Institute of Scientific and Technical Information of China (English)

    梁元耀; 方峰; 叶一强; 赖开平; 张雪旺; 龚明霞

    2011-01-01

    [目的]探讨制备30%乙氧氟草醚·乙草胺水乳剂产品的方法.[方法]以乙氧氟草醚、乙草胺、乳化剂、溶剂、抗冻剂、消泡剂等为主要原料,对30%乙氧氟草醚·乙草胺水乳剂的制备方法及配方中各组分的最佳含量进行了研究,并对该水乳剂各项性能指标进行了测试评价.[结果]30%乙氧氟草醚·乙草胺水乳剂各组分的最佳配比为:5.0%乙氧氟草醚,25.0%乙草胺.15.0%200#溶剂油,5.2% S-80乳化剂,2.8% 602# 乳化剂,4.0%乙二醇,0.3%消泡剂,自来水补足100%.经测试,所得制剂外观、分散性、乳液稳定性、热储析水率及分解率等均符合水乳剂标准.[结论]30%乙氧氟草醚·乙草胺水乳剂加工工艺较简单,性能稳定,质量可靠,且毒性低,贮运及使用安全,与环境相容性好,成本较低,具有较强的市场竞争力.%[ Objective] The technique of the preparation of 30% oxyfluoffen and acetochlor emulsion in water was researched. [ Method] The method of 30% oxyfluorfen and acetochlor emulsion, in which the oxyfluoffen, acetochlor, emulsifier, solvent oil, antifreeze and antifoaming agent was used as main raw material, and its formulation was optimized. And the parameter of the formulation was evaluated. [ Results ] The best formulation consisted of 5.0% oxyfiuorfen, 25.0% acetochlor, 15.0% solvent oil 200#, S-80 emulsifier 5.2%, 602# emulsifier 2.8%, ethylene glycol 4.0%, antifoaming agents 0.3% and water. And the testing result of the formulation indicated the appearance,dispersion, emulsion stability, heat storage rate and decomposition rate of water met the specification required. [ Conclusion] The technique of 30% oxyfluorfen acetochlor EW was relatively simple, with stable performance, reliable quality, low content of toxicity, easy storage and safety utilization and also with good environmental compatibility, low cost and strong market competitiveness.

  15. Research on Mutual Influence between the Enclosure Structures and the Heat Exchange Pipes in Enclosure Structures%围护结构内的热交换管和结构的相互影响研究

    Institute of Scientific and Technical Information of China (English)

    夏才初; 朱建龙; 曹诗定

    2012-01-01

    地源热泵系统是对地温能进行利用的一种新型技术,其中在地下连续墙或钻孔灌注桩内埋设热交换管称为墙埋管和桩埋管.但是在地下连续墙或灌注桩中埋管是否会对其承载能力造成影响,以及地下连续墙或灌注桩的变形是否会对埋管产生影响分别是结构和暖通两个专业关心的问题.通过地下连续墙和灌注桩埋管前后的截面面积和惯性矩的变化,分析了埋管对其承载能力的影响.根据围护结构的结构特点以及允许位移,分析了围护结构的变形对埋管的影响.同时还研究了在地源热泵运营时,防冻液渗入混凝土可能引起的对围护结构的影响及其避免措施,研究结果表明,围护结构内埋管对其承载能力的影响相当小,围护结构的变形也不会影响热交换管的正常使用.%As a new kind of building energy saving technology which makes use of geothermal energy, the ground-source heat pump comprises the heat exchange pipes buried in the diaphragm walls or in cast-in-situ bored piles which are called energy walls and energy piles respectively. But both the heating and ventilating discipline and the structure discipline are caring for two aspects: whether the pipes will influence the bearing capacity of the enclosure structure and whether the deformations of the enclosure structure will influence the buried pipes. The bearing capacity influenced by the buried pipes is analyzed through the variation of the moment of inertia and the area of the diaphragm wall and the bored pile. The buried pipes influenced by the enclosure structure are studied according to the characteristics of the enclosure structures and the allowable displacements. It is also discussed that the antifreezing fluid penetrating the concrete will have an effect on the enclosure structure when the heat pump system is in operation, and the solutions to the prevention measures are presented. The results show that the buried pipes

  16. Effect of exogenous abscisic acid on physiological characteristics of Sabina seedlings under low temperature stress%外源脱落酸对低温胁迫下圆柏属植物幼苗生理特性的影响

    Institute of Scientific and Technical Information of China (English)

    杨志娟; 陈银萍; 李冬花; 张正庆; 郝海艳; 张风霞; 苏向楠

    2015-01-01

    The effect of exogenous ABA on membrane lipid peroxidation,osmotic regulation substances and antioxidant enzyme activities in the leaves of Sabina species under low temperature stress at -4 ℃ for 9 days was analyzed by determining the relative water content (RWC),relative electrical conductivity (REC),contents of malondialdehyde (MDA),soluble sugar (SS),soluble protein (SP),proline (Pro)and carotenoid (Car), activities of superoxide dismutase (SOD ),peroxidase (POD ),catalase (CAT ),ascorbic acid peroxidase (APX)and glutathione reductase (GR)in the leaves of 3-year-old seedlings of Sabina przewalskii and Sabina chinensis pretreated with different concentrations of ABA to provide a theoretical basis for fostering more anti-freeze evergreen varieties.The results indicated that certain concentrations of ABA could maintain the stability of membrane system and increase the contents of osmotic regulators and antioxidant enzyme activities,enhance freezing tolerance of plant,the optimum ABA concentration was found to be 30 mg/L for Sabina chinensis and 40 mg/L for Sabina przewalskii.The chilling tolerance of Sabina przewalskii is stronger than that of Sabina chinensis in the pretreatments with ABA.It is demonstrated that appropriate concentration of ABA could help to increase the chilling resistance of Sabina species.%以3 a生圆柏和祁连圆柏幼苗为材料,采用不同浓度脱落酸(ABA)预处理两种圆柏属幼苗,测定-4℃低温胁迫处理第9 d叶片相对含水量(RWC)、相对电导率(REC)、丙二醛(MDA)、可溶性糖(SS)、可溶性蛋白(SP)、脯氨酸(Pro)和类胡萝卜素(Car)含量及超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)、抗坏血酸氧化酶(APX)和谷胱甘肽还原酶(GR)活性,分析外源AB A对低温胁迫下圆柏属植物叶片膜脂过氧化和渗透调节物质的影响,为培育较多品种的抗冷冻常绿植物提供理论依据

  17. A literature review on changes of small molecules of diapause insects during overwintering period%滞育昆虫小分子含量变化研究进展

    Institute of Scientific and Technical Information of China (English)

    丁惠梅; 马罡; 武三安; 赵飞; 马春森

    2011-01-01

    It is difficult to determine the diapause intensity and health status of diapausing insects while these are overwintering. However, this can be achieved by measuring certain biochemieals in insects' bodies thereby providing useful information for population forecasting. By reviewing the literature on the bio-molecules of diapause insects, we here summarize: 1 ) methods for correlated studies; 2) changing patterns of certain bioehemicals including sugar, polyol, fat and protein; 3 ) the factors, including temperature, diapause intensity and their interactions, that influence the content of these bioehemieals. During the overwintering period, glycogen, which serves as primary energy storage, can be transferred into a series of small antifreeze molecules, including trehalose, glucose/fructose, plyeerol, sorbitol/mannitol, inositol,fatty acids and amino acids. These bio-molecules can protect diapausing insects by stabling membrane structures and maintaining protein function. Glycogen showed the following four trends during diapause: 1 ) first decrease and then increase; 2) first increase and then decrease; 3 ) continuous increase and continuous decrease. The function of fat is similar to glycogen. Because temperature is necessary for internal bio-molecule synthesis and transformation it is essential that insects that go through a relatively deep intensity diapause are able to detect external temperature fluctuations. These results provide a novel approach to predicting insect population trends.%越冬期间昆虫的滞育深度和虫体健康状态从表面难以判断,但通过虫体生化物质的测定,可以有效解决这一难题,为预测预报提供可靠信息.本文从越冬期生化物质的变化规律和主要影响影子两部分综述了国内外越冬期滞育昆虫的生化研究进展.国内外研究表明,糖原是主要的能量物质,可以转化为海藻糖、葡萄糖/果糖、甘油、山梨醇/甘露醇、肌醇、脂肪酸、氨基

  18. Traffic safety and environmental impacts. Synergies and conflicts; Liikenteen turvallisuuden ja ympaeristoevaikutusten synergiat ja vastakkainasettelut

    Energy Technology Data Exchange (ETDEWEB)

    Pollanen, M.; Ahlroth, J.; Aalto, E.; Liimatainen, H. [Tampere Univ. of Technology (Finland). Transport Research Centre Verne

    2013-06-01

    transport is an example of a synergetic measure with positive effects on both safety and the environment. Significant synergies are also achieved by promoting the renewal of vehicle stock, improving the smoothness and reliability of rail transport, reducing speed limits on highways and adopting intelligent speed adaptation systems, promoting a Single European Sky and educating, monitoring and encouraging anticipatory and economical driving habits in road and rail traffic. The greatest conflicts are related to winter traffic: the antiskid treatment of roads and streets, limiting the use of studded tyres, heating switches in rail traffic, the anti-freeze treatment of aeroplanes, and the winter maintenance of runways. Other contradictory measures include vegetation control, increasing the attractiveness of bicycling and calming traffic flow through the use of elevated pedestrian crossings and bumps. Based on the results of the study, the synergies between safety and the environment can be reinforced and the conflicts mitigated. The implementation of the most synergetic measures can be promoted by combining the perspectives of safety and the environment also in the justifications for the measures. (orig.)

  19. Intoxicación por alcoholes Alcohol intoxication

    Directory of Open Access Journals (Sweden)

    J. Roldán

    2003-01-01

    protect the patient from secondary complications. Methanol, or alcohol fuel, is used as a solvent, and can also be found as an adulterant of alcoholic drinks. Poisoning by oral means is the most frequent. Oxidized in the liver through dehydrogenase enzyme alcohol, toxicity is due to its metabolites, formaldehyde and formic acid. The clinical picture basically consists of cephalea, nausea, vomiting, hypotension and depression of the central nervous system. The optic nerve is especially sensitive, with total and irreversible blindness as a possible result. Ethylenglicol is used as a solvent and as an antifreeze; toxicity is due to an accumulation of its metabolites. The clinical picture includes symptoms that are held in common with methylalcohol intoxication. Kidney failure due to tubular necrosis and the deposit of oxalate crystals can occur.

  20. 直接空冷岛顺流基管管内冷凝的传热传质分析%Analysis for Heat and Mass Transfer of Condensation inside Down-Flow Unit Tube of Air Cooled Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    邓慧; 白焰; 李小缤; 党伟玮; 李欣欣

    2015-01-01

    the condensate sub-cooling temperature doesn't agree with actual measurement value very well. The result of this study is of great significance for optimization design of down-flow unit tubes, and also, it is meaningful for antifreezing protect of ACHE in winter.

  1. Internal water ocean on Titan: Place for prebiological and biological processes

    Science.gov (United States)

    Simakov, Michael B.

    Beneath the crust of Saturn's moon Titan may lurk a huge watery ocean, buried below several tens of kilometers of ice. The most recent models of the Titan's interior lead to the conclusion that a substantial liquid layer exists today under relatively thin ice cover. Lorenz has found that the internal oceans are mandated for the large icy satellites. Thermal evolution models also predict the existence of thick ( 300 km) liquid layer with relatively thin ( 80 km) ice cover. Spohn and Schubert have shown that even radiogenic heating in a chondritic core alone may suffice to keep a water ocean inside large icy satellites. Taking into account non-Newtonian viscosity of the water ice in planetary condition, the water ocean on Titan might have survived to date due to only radioactive heat source. The Cassini spacecraft's data show some features consisting with possible ocean inside the satellite. So, the existing of liquid water ocean within icy world can be a consenquence of the physical properties of water ice, and they neither require the addition of antifreeze substances nor any other special conditions. Mass balance calculations modeled an extraction of the elements into the aqueous phase from chondritic material show that Titan's extensive subsurface ocean likely contains dissolved salts from exogenic and endogenic materials resembling to carbonaceous chondrite rocks incorporated into the satellite during its formation and released at the time of planetary differentiation. The presence of solutes into oceanic water is probably unavoidable in the context of water-rock interaction either early in the history of the satellite or at the present time. The low and high-temperature alteration of primitive accreted material leads to form of a complex water solution of such cations as K, Na, Mg, Ca, Mn, Fe and anions as SO4 2- , Cl- , Br- , CO3 2- , HCO3 - and others along with nitrogen compounds. Phosphorus, sulfur, micro-and macronutrients have to be abundant inside bottom

  2. LabVIEW-operated novel nanoliter osmometer for ice binding protein investigations.

    Science.gov (United States)

    Braslavsky, Ido; Drori, Ran

    2013-01-01

    Ice-binding proteins (IBPs), including antifreeze proteins, ice structuring proteins, thermal hysteresis proteins, and ice recrystallization inhibition proteins, are found in cold-adapted organisms and protect them from freeze injuries by interacting with ice crystals. IBPs are found in a variety of organism, including fish(1), plants(2, 3), arthropods(4, 5), fungi(6), and bacteria(7). IBPs adsorb to the surfaces of ice crystals and prevent water molecules from joining the ice lattice at the IBP adsorption location. Ice that grows on the crystal surface between the adsorbed IBPs develops a high curvature that lowers the temperature at which the ice crystals grow, a phenomenon referred to as the Gibbs-Thomson effect. This depression creates a gap (thermal hysteresis, TH) between the melting point and the nonequilibrium freezing point, within which ice growth is arrested(8-10), see Figure 1. One of the main tools used in IBP research is the nanoliter osmometer, which facilitates measurements of the TH activities of IBP solutions. Nanoliter osmometers, such as the Clifton instrument (Clifton Technical Physics, Hartford, NY,) and Otago instrument (Otago Osmometers, Dunedin, New Zealand), were designed to measure the osmolarity of a solution by measuring the melting point depression of droplets with nanoliter volumes. These devices were used to measure the osmolarities of biological samples, such as tears(11), and were found to be useful in IBP research. Manual control over these nanoliter osmometers limited the experimental possibilities. Temperature rate changes could not be controlled reliably, the temperature range of the Clifton instrument was limited to 4,000 mOsmol (about -7.5 °C), and temperature recordings as a function of time were not an available option for these instruments. We designed a custom-made computer-controlled nanoliter osmometer system using a LabVIEW platform (National Instruments). The cold stage, described previously(9, 10), contains a metal

  3. 中国东北典型黑土区土地整理规划设计模式%Planning and Design Modes of Land Consolidation in Typical Black Soil of Northeastern China

    Institute of Scientific and Technical Information of China (English)

    赵华甫; 吴克宁; 王自威; 王金满; 靳取货; 刘园秋

    2011-01-01

    Relying on fertile black soil resources, northeastern China has been developed as the biggest commodity grain base. Meanwhile, for hilly terrains, excessive use of concentrated rainfall and from other reasons, black soil is facing heavy soil erosion, fertility decline, and soil salinization, etc. Reasonably conducting and implementing land consolidation planning and design through ecological reconstruction, erosion control, and soil fertility are sound ways to cure those problems. Based on characteristics of natural resources and agricultural economic development trends in northeastern China, the authors discussed concepts, and planning and design technologies targeted for land consolidation in Lunhe Town, Hailun County, Heilongjiang Province. Guided by the philosophy of harmony between human and nature, the frame-oriented method and problem-oriented approach were jointly used to analyze the key problems and technologies needed for the land consolidation project in this area. Results of frame-oriented method analysis show that factors, like unreasonable land use spatial patterns, imperfect road systems, and fragmental ditches,are the major problems in the study area. Physical conditions, such as hilly terrains, concentrative rainfall, long-term extreme low temperature, and societal reasons such as mismanagement and deforestation, can not only lead to heavy soil degradation and serious damage of hydraulic constructions, ditches, and roads, but also result in low productivity and an imbalance among ecosystems. A series of engineering projects were proposed, such as land leveling projects,irrigation and drainage engineering, and road engineering residential renovation, etc. Meanwhile,other innovative methods of special land consolidation engineering design, such as easy disassembly, anti-freeze & anti-leakage back to plasma channel design, and anti-road-mudding road design, were suggested to reduce destmction of infrastructure due to alternating extreme low

  4. Heating system design of complementarity over solar energy and low ebb electric%太阳能与谷电互补供热系统设计

    Institute of Scientific and Technical Information of China (English)

    周兵

    2011-01-01

    Solar energy assisted by low ebb electricity was used for heating, two heat storage tanks were adopted to gather and supply heat alternately. When normal heat collecting or low temperature preheating, the one which had the lower water temperature in two heat storage tanks had the priority to collect heat and cycle operation; If water temperature was same, heat storage tank was set to run prior to heat-collecting tank .When normal heating, night anti-freezing cycle and low temperature maintain running, solar collection system was used to heat the heat storage tank prior to ebb electricity. When holiday collecting or low temperature maintain heating, two storage tanks run collecting and cycling operation at the same time. When heating cycling pumps and using heating pumps running, heating should be first considered, and it stopped when the return water temperature of using heating system higher or equal to the maximum warm temperature in priority. Programmable controller and configuration software technology realized the constant temperature、constant time and constant temperature during system heat collecting and supplying time. This complementarity system could replace the traditional high-energy boilers,and energy-saving rate was above 30 %.%利用太阳能辅以低谷电加热,采用两个储热罐进行交替轮流集热、供热.当正常集热或低温预热时,两个储热罐的水温低者优先集热循环运行;若两储热罐水温相同,则设定储热罐优先集热循环运行.当正常供热、夜间防冻循环和低温维持运行时,太阳能集热系统优先于低谷电循环运行给储热罐加热.当假日集热或低温保温供热时,同时给两储热罐集热循环运行.供热循环水泵和用热循环水泵的启动运行,以供热时优先,其停止运行以用热系统的回水温度大于或等于取暖温度的最大设定值者优先.以可编程控制器和组态软件技术,实现了系统集热、供热时段的定温、定

  5. 土壤跳虫适应低温环境的策略与机制研究进展%Strategies and mechanisms of soil springtails in adapting lower temperature environment:Research progress

    Institute of Scientific and Technical Information of China (English)

    刘晶; 王云彪; 吴东辉

    2012-01-01

    Low temperature and drought are the main environmental factors threatening the animals living in arctic area and cold temperate regions. To adapt the severe environment, the animals should adopt appropriate strategies. As a group of arthopods with freeze-avoiding strategy, soil springtails have the similar ecological mechanisms and modes of cold resistance/tolerance as insects, manifesting in the cold acclimation and drought tolerance to decrease the damage of ice crystal formation. During cold acclimation, there are a rapid increase of glycerol, a rapid decrease of fucose and glucose, and the production of anti-freeze proteins (AFP) , and exists the inter-transformation of different kinds of lipids to improve the flow of cell membrane to protect the cell from low temperature injury. In addition, soil springtails have their own specific modes and mechanisms to tolerate low temperature stress, mainly the vertical migration under the protection of snow cover and the excretion of ice nucleator from haemolymph, illustrating that it' s of significance to research the cryo-biology of soil springtails. This paper summarized the modes and mechanisms of soil springtails in tolerating low temperature environment, reviewed the research progress on the eco-physiology of the springtails, discussed the existing problems of the researches on the low temperature tolerance of the springtails, and prospected the research directions of the springtails low temperature ecology under the background of global change.%低温和干燥是极地及寒温带地区动物的主要环境胁迫因子.为适应恶劣的环境,此区域的动物必须运用有效的方式来适应其栖息环境.土壤跳虫是典型的以避免体液结冰为主要策略来适应低温环境的动物类群,其抗低温的生态策略和模式与昆虫存在相似之处,表现在其利用冷驯化及与干旱协同作用,降低冰晶形成的伤害.在抗低温过程中,其体内甘油等小分子物质含量

  6. 3.0T高场强核磁共振设备机房布局及施工准备%Research on the layout and construction preparation for 3.0T high-field nuclear magnetic resonance equipment room

    Institute of Scientific and Technical Information of China (English)

    孙继江; 何晓彬; 步岩生

    2013-01-01

    ventilated, northern region need to get the winter outdoor antifreeze. Exhaust air change per hour between magnet design of not less than 12 times. Conclusion: Hospital construction for large equipment and ancillary equipment is installed in the process of each link to match reasonably, pay attention to the collaboration between different units and at the same time. Reasonable equipment layout and construction preparation is the guarantee of equipment installation smoothly.

  7. Comparative Study of LDL Extracted from Five Avian Species on the Cryopreservation of Boar Sperm%5种禽类卵黄低密度脂蛋白对猪精子冷冻效果的影响

    Institute of Scientific and Technical Information of China (English)

    吕瑞凯; 胡建宏; 王红; 程亮; 江中良; 李青旺; 姚俊; 张鹏飞

    2011-01-01

    为了确定具有最佳抗冷冻效果的禽类卵黄低密度脂蛋白(LDL)及其添加质量分数,在猪精液冷冻稀释液中分别添加质量分数为6%、7%、8%、9%和10%的鸡、鸭、鹌鹑、鸽子和鸵鸟的卵黄LDL,分析不同禽类的LDL对猪精子的冷冻保存效果.结果表明,稀释液中添加质量分数为9%的鸡、鸭、鹌鹑、鸽子卵黄LDL以及质量分数8%的鸵鸟卵黄LDL时,冷冻-解冻后精子活率最高,分别达到42.33%、35.63%、31.47%、47.33%和36.40%.以5种禽类LDL最佳质量分数配制冷冻稀释液冷冻精子,发现质量分数为9%的鸽蛋LDL冻存猪精子时解冻后精子活率达到47.33%,顶体完整性达到62.57%,质膜完整性达到48.13%,均显著优于其他处理组(P<0.05).说明鸽子卵黄LDL对猪精子具有良好的冷冻保护性能,可提高猪精子抵抗低温打击的能力.%Low density lipolipid (LDL) can protect sperm from freezing damage during the sperm frozen-thawed process. In order to distinguish the efficiency of LDL extracted from different avian species, to confirm which one and how much of it has the best anti-freezing effect, LDL extracted from eggs of hen, duck, quail, pigeon and ostrich with the mass fraction of 6%, 7%, 8%, 9% and 10% was added into the cryopreservation diluents of boar sperm separately. The result showed that after the frozen-thawed process, LDL extracted from eggs of hen, duck, quail and pigeon with concentration of 9% and ostrich LDL with concentration of 8% could protect sperm with highest livability of 42. 33%, 35. 63% , 31. 47%, 47. 33% and 36. 40%, respectively. They were significantly better than that of other concentrations (P<0. 05). Among the cryopreservation diluents and cryopreservation sperm prepared with the five avian species with the optimum concentration, it was found that the 9% pigeon LDL group showed 47. 33% sperm livability, 62. 57% acrosome integrity and 48. 13% membrane integrity after

  8. Getting Real: A General Chemistry Laboratory Program Focusing on "Real World" Substances

    Science.gov (United States)

    Kerber, Robert C.; Akhtar, Mohammad J.

    1996-11-01

    In order to confront the abstractness of the freshman chemistry syllabus and the consequent failure of students to relate what they learn to their everyday lives, we have designed a new freshman laboratory program. It is intended as an interface between the substances that surround the students in their ordinary lives and the abstract principles presented in chemistry classrooms (1). A laboratory should provide the organized experiences and observations that underlie the intellectual constructs of chemistry, and tying these experiences and observations to the real world can help to provide motivation for study of the principles. The freshman laboratory program constitutes the foundation for subsequent laboratory courses. However, the good habits we strive to develop there (careful observation, thorough record keeping, proper use of equipment, objective data analysis) are essential to all scientific work, and are intended to provide lasting educational value for all students, especially those who do not take later laboratory work. What We Do A list of the laboratory exercises carried out during 1994-1995 is presented in Table 1. The course incorporates the following features. 1. The exercises deal with recognizable, everyday substances, not just with "chemicals". That "baking soda" and "sodium bicarbonate" are the same is a chemical truism of which the students may be aware, but the visible presence of the Arm and Hammer box nevertheless helps them to make connections to the world outside the laboratory. Perceiving the connections, students may be inspired by curiosity to understand chemical phenomena better, not just to tolerate what they are being taught, as an irrelevant hurdle in the pursuit of a career. 2. Since many significant substances around students in the everyday world are organic, we work in the lab with organic as well as the usual inorganic materials. These include analgesics, vitamins, antifreeze, foodstuffs, dyestuffs, plastics, and fibers. In

  9. The H2O2-H2O Hypothesis: Extremophiles Adapted to Conditions on Mars?

    Science.gov (United States)

    Houtkooper, Joop M.; Schulze-Makuch, Dirk

    2007-08-01

    evolved into employing H2O2 as an antifreeze, which would also have the function as a water collector. If we would find life on Mars based on an intracellular H2O2-H2O mixture, this would not necessarily imply an independent origin of terrestrial and martian life. For that, a detailed study of the biochemistry and genetics is needed. The transfer of terrestrial organisms to Mars or vice versa is a possibility given favorable conditions for the origin and persistance of life on both planets early in solar system history (Schulze-Makuch and Houtkooper, 2007). The transfer of terrestrial organisms by early spacecrafts to Mars that either landed or crashed is a possibility, but it is not plausible that these organisms evolved in a few years. We suggest that we already have evidence of their existence from the Viking landers in two widely distant locations. The H2O2-H2O hypothesis does explain the Viking observations remarkably well, especially (1) the lack of organics detected by GC-MS, (2) the lack of detected oxidant(s) to support a chemical explanation, (3) evolution of O2 upon wetting (GEx experiment), (4) limited organic synthesis reactions (PR experiment), and (5) the gas release observations made (LR experiment)(Houtkooper and Schulze-Makuch, 2007). From the amounts of evolved CO2, O2 and N2 in the GEx experiment it can be concluded that the organisms have an excess oxidative content. This is a problem since in any destructive test, even by laser desorption-mass spectrometry (LDMS), the organisms may decompose completely into H2O, CO2, O2, and N2. The same will occur if the organisms are exposed to excess water, as they will perish due to hyperhydration. The consequence for future biology experiments is that the most fruitful approach may be the detection of metabolism under close to local environmental conditions, especially avoiding the addition of too much water. Of the Viking experiments, the PR experiment which aimed at carbon assimilation was the closest to

  10. Study of Hemolysis Performance for ChinaHeart Ventricular Assist Device%ChinaHeart心室辅助装置溶血性能研究

    Institute of Scientific and Technical Information of China (English)

    徐创业; 蔺嫦燕; 吴广辉; 刘修健; 杨朋; 渠文波

    2012-01-01

    outflow (5±0.25) L/min, the average pressure (100±3) mmHg, drove fresh goat blood after being anti-freezed, detected plasma free hemoglobin(FHB) and hematokrit(Hct) before pumping and at every hour of pumping for 4 hours, and then calculated the normalized index of hemolysis (NTH). In vivo test, we took 2 healthy male small tail han sheep, implanted blood pump into heart apex after anesthesia, and set up a auxiliary cycle bypass from the left ventricular through VAD to descending aorta, controlled blood pump auxiliary flow accounting for 60% of the total cardiac output, then proceeded the auxiliary vivo test, regularly drew blood to detect FHB and Hct, finally, compared the results of the two test with typical blood pumps at home and abroad to evaluate the hemolytic characteristics of ChinaHeart VAD crosswise. Results In vitro test, the blood pump runned smoothly, had normal temperature, no leakage and no block. The NIH of blood pump in vitro is (0.0076±0.0016)g/100L. In vivo test, 2 sheep had been successfully assisted for 20 and 38 days respectively with no obvious renal and hepatic dysfunction. The FHB content showed a rising trend, with the maximum value of 0.0864g/L (20 days) and 1 0957g/L (38 days), and then decreased to the preoperative levels gradually. Conclusion ChinaHeart VAD blood pump has favorable hemolytic performance in vitro and in vivo, and can perform long-term survival experiment of animals in vivo test.

  11. HF粉煤灰混凝土的力学变形及抗冲磨性能试验研究%Experimental Research on HF Fly Ash Concrete Mechanical Deformation and Abrasion Resistance

    Institute of Scientific and Technical Information of China (English)

    张建博; 杜应吉

    2012-01-01

    为了研究了不同粉煤灰掺量、水胶比、HF抗;中磨剂掺量对混凝土的力学及变形性能和耐久性的影响规律,进行了HF粉煤灰混凝土的抗压强度、极限拉伸、抗压弹性模量等力学及变形性能试验以及HF粉煤灰混凝土的抗冻、抗渗、抗冲磨等耐久性试验。结果表明:在相同HF抗冲磨剂掺量和水胶比情况下,混凝土抗压强度并不是随粉煤灰掺量的增加而增加,而是都表现出先增加后降低的规律性现象;在相同粉煤灰掺量和水胶比情况下,随HF抗冲磨剂的掺量的增加其抗冲磨强度得到较大提高,混凝土抗压强度也有所提高,但是在提高HF掺量来增加混凝土强度的同时并考虑与之相匹配的水胶比时,这样能使HF抗冲磨剂对混凝土强度的效用更好地发挥出来;从粉煤灰掺量对不同龄期混凝土多个力学及变形性能和耐久性性能的影响规律来看,HF粉煤灰混凝土的设计龄期为90d时,粉煤灰掺量宜为25%以内,不宜超过30%;随水胶比在一定范围内的降低,混凝土抗压强度、极限拉伸值、抗拉弹性模量、轴心抗拉强度、抗压弹r陛模量、轴心抗压强度、抗冲磨强度均规律性提高。%In order to study the effects of different amounts of fly ashes, water cement ratio, content of anti-abrasion agent HF to concrete mechanics, deformation performance and durability, HF fly ash concrete's mechanics performance experimental-compressive strength, tensile, compressive modulus of elasticity and HF fly ash concrete's antifreeze, impermeability and anti-abrasion durability experimental are carried out. The results show that in the same HF anti-abrasion agent content and water-hinder ratio, compressive strength of concrete is not increased with the increasing dosage of fly ash, but showed the phenomenon of first rose and then dropped; in the same amount of fly ash and water-binder ratio, with the mixed

  12. Increase insulation effect of polyurethane board pasting on closed aqueduct surface in cold regions%北方寒冷地区封闭渡槽粘贴聚氨酯板提高保温效果

    Institute of Scientific and Technical Information of China (English)

    刘德仁; 张东; 张世民

    2013-01-01

    monitoring analysis and numerical calculation analysis. In this paper, according to an aqueduct engineering practice with non-pressure water delivery in cold region of northern China, a scale model test of an aqueduct is undertaken in an indoor environment cabinet to study the anti-freezing and insulation effects of pasting polyurethane insulation board on the surface of the aqueduct under low temperature environment in winter. In order to study the insulation effects of polyurethane insulation board on aqueduct, the tests are mainly divided into two cases: pasting and without pasting polyurethane insulation board on the surface of the aqueduct model. By the tests, the influence of the external environment temperature and rate of flow on water flow temperature during the process of water delivery of the aqueduct in winter were studied. It is concluded from the test that pasting polyurethane insulation board on aqueduct surface has obvious effects on preventing the water temperature in the aqueduct from decreasing, reducing about 45%of the water temperature reduction. In order to ensure the insulation effects of polyurethane insulation board, polyurethane insulation board should be pasted on the surface of aqueducts closely to prevent phenomena of bulging and shedding. The aqueduct is exposed to the atmosphere and is seriously affected by the temperature, so when setting aqueduct in actual water diversion project, it should not be set too long to ensure the safe operation of these projects. Test results in the paper can provide design basis and reference for the same closed aqueduct water diversion project in cold regions of northern China.

  13. Increase insulation effect of polyurethane board pasting on closed aqueduct surface in cold regions%北方寒冷地区封闭渡槽粘贴聚氨酯板提高保温效果

    Institute of Scientific and Technical Information of China (English)

    刘德仁; 张东; 张世民

    2013-01-01

    Areas of northern China are mainly in the temperate monsoon climate zone and temperate continental climate zone, it is cold in winter, and the air temperature is low, which has a big influence on water diversion facilities, especially aqueduct. As for closed aqueduct water diversion projects which need to be operated in winter with non-pressure water delivery in cold regions of northern China, it is of great significance to study and research the safe operation under low temperature environment in winter. With the rapid development of the construction of water diversion projects, the original research results about aqueducts mainly lie in the structural stress of the aqueduct, then the effects of fluid-solid coupling, earthquake, wind and temperature stress, and other factors are gradually considered, seismic and reliability theory is also introduced into the design of diversion facilities. For water diversion projects in northern China, the problem of the safety of water diversion under low temperature environments in winter should also be considered. The present study in freezing disease of water diversion project and safety operation in winter is relatively less, which are mainly in the fields of monitoring analysis and numerical calculation analysis. In this paper, according to an aqueduct engineering practice with non-pressure water delivery in cold region of northern China, a scale model test of an aqueduct is undertaken in an indoor environment cabinet to study the anti-freezing and insulation effects of pasting polyurethane insulation board on the surface of the aqueduct under low temperature environment in winter. In order to study the insulation effects of polyurethane insulation board on aqueduct, the tests are mainly divided into two cases: pasting and without pasting polyurethane insulation board on the surface of the aqueduct model. By the tests, the influence of the external environment temperature and rate of flow on water flow temperature during

  14. Freezing properties of Antarctic bacterial exopolysaccharides solutions by differential scanning calorimetry%南极细菌胞外多糖溶液冻结特性的差示扫描量热研究

    Institute of Scientific and Technical Information of China (English)

    何培青; 李江; 王昉; 顾敏芬; 沈继红

    2009-01-01

    The freezing, melting, enthalpy change and hydration properties of Antarctic bacterial exopolysaccharides (EPSs)solutions have been investigated by differential scanning calorimetry, and the possible relations between concentration, molecular weight and antifreezing activities of exopolysaccharides have also been analyzed. Experimental results showed that, during the course of freezing, only Pseudoalteromonas sp. S-15-13 EPSs (molecular weight, 6.2×10~4Da) at 0.25% could inhibit nucleation of ice, and depress the freezing temperature by (1.07±0.62)℃. Reduction of freezing enthalpies meant the inhibited growth of ice nuclei and reduced size of crystallites. As compared with pure water, Shewanella sp. 5-1-11-4 EPSs (molecular weight, 1.2×10~3Da) and Moritella sp. 2-5-10-1 EPSs (molecular weight, 3.0×10~3Da) at 0.125% could reduce freezing enthalpies by 17.15% and 29.13%, respectively. S-15-13 EPSs ranged between 0.125%-0.5% could reduce freezing enthalpies, EPSs at 0.125% could reduce freezing enthalpy by 30%, and its non-freezing water was (0.292±0.05) g/g. During the course of freezing, all the EPSs reduced the melting temperature and melting enthalpies, thereby enhanced the ice melting and reduced the size of crystallites. As compared with pure water, EPSs of 5-1-11-4 and 2-5-10-1 at 4.0%, EPSs of S-15-13 at 0.5% reduced the melting temperatures by (2.70±0.15)℃, (2.30±0.39)℃ and (4.66±0.42)℃, respectively. The results of this study suggested that, EPSs could change the freezing properties of ambient water to defense bacteria from the harm of ice. The anti-crystallites effect of EPSs was stronger with a higher molecular weight.%采用差示扫描量热法,测定几种南极细菌胞外多糖(简称,EPSs)溶液的结晶、熔融、焓转变以及水合性质等冻结特性,分析了EPSs的浓度和分子量与其抗冻活性的关系.结果表明,在溶液冻结过程中,仅0.25%的Pseudoalteromonas sp.S-15-13 EPSs(分子量,6.2×10~4Da)可抑制冰

  15. Research progress in the catalysts for vapor phase hydrogenation of dimethyl oxalate to ethylene glycol%草酸二甲酯气相法加氢制乙二醇催化剂研究进展

    Institute of Scientific and Technical Information of China (English)

    付金萍; 赵洋; 周强; 王树华; 吴周安; 谢冠群; 罗孟飞

    2014-01-01

    乙二醇是重要的化工原料,广泛应用于阻冻剂、燃料电池和聚酯工业等领域。传统制备乙二醇路线有基于石油路线的环氧乙烷水合法以及基于煤和天然气路线的C1合成法。C1路线合成乙二醇是CO氧化偶联生成草酸二甲酯,草酸二甲酯再催化加氢合成乙二醇。设计和制备高效草酸二甲酯加氢催化剂是实现煤制乙二醇工业化关键。草酸二甲酯加氢催化剂主要有Ru基均相催化剂和Cu基非均相催化剂,其中,无Cr的Cu基催化剂( Cu/SiO2)是研究重点。影响Cu/SiO2催化性能的主要有载体、制备方法和助剂。载体类型不仅影响活性物种与载体之间的相互作用,而且影响活性物种分散度,具有高表面积和有序介孔结构的载体能够提高Cu物种分散度,从而显著提高催化剂活性。制备Cu/SiO2催化剂的方法有蒸氨法、浸渍法、沉积沉淀法、离子交换法和溶胶-凝胶法等。蒸氨法制备的Cu/SiO2形成铜氨络合离子,使Cu物种得到很好分散,还原后催化剂表面Cu+含量较高。Mo、Co、Ni和B等助剂的添加可以调变Cu物种的价态和分散度,提高催化剂性能。添加助剂时,要综合考虑助剂的引入对催化剂酸碱性质、活性物种分散度和载体孔径结构等的影响。研究认为,草酸二甲酯加氢机理是Cu0与Cu+的协同作用,Cu0是催化剂上的活性位点,活化H2;Cu+起亲电子的L酸作用,激化CO键提高草酸二甲酯中酯基的反应。催化剂失活的主要原因是产物乙醇酸甲酯在催化剂表面较难脱附以及反应过程中催化剂烧结。Cu/SiO2催化剂存在热稳定性差等缺陷,制备高稳定Cu基催化剂是今后发展方向。%Ethylene glycol( EG)is an important fine intermediate,which is conventionally used in the fields of antifreeze,fuel cell and polyester manufacture,etc. There are two kinds of synthetic routes of ethylene glycol

  16. Research Progress on the Physiological and Molecular Mechanisms of Woody Plants Under Low Temperature Stress%木本植物低温胁迫生理及分子机制研究进展

    Institute of Scientific and Technical Information of China (English)

    乌凤章; 王贺新; 徐国辉; 张自川

    2015-01-01

    护细胞;热休克蛋白( HSPs)调节蛋白质的折叠和运输,恢复钝化酶的活性;抗氧化酶系统清除氧自由基和过氧化氢;早期光诱导蛋白参与高光胁迫适应过程,这些蛋白在树木抗冻机制中具有重要作用。在树木抗冷(冻)领域,未来应加强对控制抗冷(冻)生理变化的转录因子及关键功能基因的全面解析,深入探讨光、温度等环境信号诱导抗冻性形成机制,使用蛋白质组学方法与其他技术相结合阐明低温胁迫下重要蛋白质表达机制和功能,完整地揭示木本植物在低温逆境下的生存机制。%Low temperature stress limits the geographical distribution of many wild plant and crops,and reduces their productivity. There are huge differences in survivability of trees to low temperature stress. Chilling sensitive trees from tropics and subtropics are irreversibly damaged at temperature condition higher than freezing point,while those species originated from temperate-zone can withstand extreme freezing conditions. In recent years,the analyses of physiological and biochemical response characteristics, transcriptome, proteome and metabolome of chilling sensitive trees and temperate-zone trees under low temperature stress have been rapidly developed,which from various levels have elucidated the physiological and molecular mechanisms that woody plant regulating low-temperature response and freezing tolerance. These analyses provide important reference for molecular breeding of freezing-tolerant woody plant by using anti-freezing related genes. Under the low temperature stress of 1—10 ℃,chilling sensitive trees would appear disorders physiological processes in water status,mineral nutrition,photosynthesis,respiration and metabolism,and hence lead to chilling damage,and even death. Calcium signal transduction pathway is the important signal transduction pathway during low temperature response process. ABA is involved in the regulation of plant stress response gene by