Sample records for antifreeze

  1. Saccharide antifreeze compositions

    Energy Technology Data Exchange (ETDEWEB)

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


    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. (United States)

    Nagel, Lilly; Budke, Carsten; Dreyer, Axel; Koop, Thomas; Sewald, Norbert


    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 glycopeptide diastereomers

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    Lilly Nagel


    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.

  4. Antifreeze life cycle assessment (LCA

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    Kesić Jelena


    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.

  5. Molecular basis for antifreeze activity difference of two insect antifreeze protein isoforms

    Institute of Scientific and Technical Information of China (English)


    The insect spruce budworm(Choristoneura fumiferana) produces antifreeze protein(AFP) to assist in the protection of the over-wintering larval stage and contains multiple isoforms. Structures for two isoforms,known as CfAFP-501 and CfAFP-337,show that both possess similar left-handed β-helical structure,although thermal hysteresis activity of the longer isoform CfAFP-501 is three times that of CfAFP-337. The markedly enhanced activity of CfAFP-501 is not proportional to,and cannot be simply accounted for,by the increased ice-binding site resulting from the two extra coils in CfAFP-501. In or-der to investigate the molecular basis for the activity difference and gain better understanding of AFPs in general,we have employed several different computational methods to systematically study the structural properties and ice interactions of the AFPs and their deletion models. In the context of intact AFPs,a majority of the coils in CfAFP-501 has better ice interaction and causes stronger ice lattice disruption than CfAFP-337,strongly suggesting a cooperative or synergistic effect among β-helical coils. The synergistic effect would play a critical role and make significant contributions to the anti-freeze activity β-helical antifreeze proteins. This is the first time that synergistic effect and its implica-tion for antifreeze activity are reported for β-helical antifreeze proteins.

  6. Molecular basis for antifreeze activity difference of two insect antifreeze protein isoforms

    Institute of Scientific and Technical Information of China (English)

    ZHOU YanXia; TAN HongWei; YANG ZuoYin; JIA ZongChao; LIU RuoZhuang; CHEN GuangJu


    The insect spruce budworm (Choristoneura fumiferana) produces antifreeze protein (AFP) to assist in the protection of the over-wintering larval stage and contains multiple isoforms. Structures for two isoforms, known as CfAFP-501 and CfAFP-337, show that both possess similar left-handed β-helical structure, although thermal hysteresis activity of the longer isoform CfAFP-501 is three times that of CfAFP-337. The markedly enhanced activity of CfAFP-501 is not proportional to, and cannot be simply accounted for, by the increased ice-binding site resulting from the two extra coils in CfAFP-501. In order to investigate the molecular basis for the activity difference and gain better understanding of AFPs in general, we have employed several different computational methods to systematically study the structural properties and ice interactions of the AFPs and their deletion models. In the context of intact AFPs, a majority of the coils in CfAFP-501 has better ice interaction and causes stronger ice lattice disruption than CfAFP-337, strongly suggesting a cooperative or synergistic effect among β-helical coils. The synergistic effect would play a critical role and make significant contributions to the antifreeze activity β-helical antifreeze proteins. This is the first time that synergistic effect and its implication for antifreeze activity are reported for β-helical antifreeze proteins.

  7. 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


    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.

  8. Antivirulence Properties of an Antifreeze Protein

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    Martin Heisig


    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.

  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


    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...

  10. Antifreeze activity enhancement by site directed mutagenesis on an antifreeze protein from the beetle Rhagium mordax. (United States)

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


    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.

  11. Protein-water dynamics in antifreeze protein III activity (United States)

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


    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.

  12. Antifreeze coatings for rotor blades of wind turbines - Final report; Antifreeze Beschichtungen fuer Rotorblaetter von Windenergieanlagen - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Siegmann, K.; Meola, G.; Hirayama, M.


    Iced rotor blades drastically reduce the energy production of wind turbines. In addition, ice throw from the iced blades can be dangerous. There are yet no convincing solutions for the icing problem. An interesting approach is the use of a rotor blade coating. We have developed a coating which influences the freezing behaviour of water. In this report, we describe tests on the antifreeze-coatings developed by us. It is shown that water droplets on the antifreeze coating freeze later than droplets on the untreated glass. This effect could lead to a non-icing of coated rotor blades, because the droplets could be blown of the blade before they can freeze. Additionally, the ice adhesion to the antifreeze coatings is measured. Ice adheres to the antifreeze coating about as good as to bare aluminium and better than to adhesion reducing coatings. (authors)

  13. Antifreeze proteins enable plants to survive in freezing conditions

    Indian Academy of Sciences (India)

    Ravi Gupta; Renu Deswal


    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.

  14. Bioinspired Antifreeze Secreting Frost-Responsive Pagophobic Coatings (United States)

    Sun, Xiaoda; Damle, Viraj; Rykaczewski, Konrad


    Prevention of ice and frost accumulation is of interest to transportation, power generation, and agriculture industries. Superhydrophobic and lubricant impregnated pagophobic coatings have been proposed, however, they both fail in frosting conditions. Inspired by functional liquid secretion in natural systems, such as toxin secretion by poison dart frost in response to predator presence, we developed frost-responsive antifreeze secreting pagophobic coatings. These are bi-layered coatings with an inner superhydrophilic ``dermis'' infused with antifreeze and an outer permeable superhydrophobic ``epidermis.'' The superhydrophobic epidermis separates the antifreeze from the environment and prevents ice accumulation by repelling impinging water droplets. In frosting conditions, the antifreeze is secreted from the dermis through pores in the epidermis either due to contact with condensed droplets or temporary switch of the epidermis wettability from hydrophobic to hydrophilic caused by surface icing. Here we demonstrate superior performance of this multifunctional coating in simulated frosting, freezing mist/fog, and freezing spray/rain conditions. KR acknowledges startup funding from ASU.


    Directory of Open Access Journals (Sweden)

    S. V. Gushchin


    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.

  16. The Antifreeze Critical Strength of Low-temperature Concrete Effected by Index

    Institute of Scientific and Technical Information of China (English)

    LIU Jun; LIU Yu; LIU Runqing


    The antifreeze critical strength and the pre-curing time of low-temperature concrete were studied by means of guaranteed rate of compressive strength and antifreeze performance for the structural safety requirement of concrete engineering, suffering once freeze damage under air environment. It is shown that the antifreeze critical strength is 3.7-4.4 MPa, pre-curing time is 18-32 h by guaranteed rate of compressive strength, and the antifreeze critical strength is 3.7-4.4 MPa, pre-curing time is 18-32 h by guaranteed rate of antifreeze performance. It can be found that the method of guaranteed rate of compressive strength is sensitive to the defect which generated by freeze damage in the concrete interior. The method is fit to evaluate the antifreeze critical strength of low-temperature concrete.

  17. 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


    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.

  18. Potential Antifreeze Compounds in Present-Day Martian Seepage Groundwater

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    Jiin-Shuh Jean


    Full Text Available Is the recently found seepage groundwater on Mars pure H2O, or mixed with salts and other antifreeze compounds? Given the surface conditions of Mars, it is unlikely that pure water could either exist in its liquid state or have shaped Mars¡¦ fluid erosional landforms (gullies, channels, and valley networks. More likely is that Mars¡¦ seepage groundwater contains antifreeze and salt compounds that resist freezing and suppress evaporation. This model better accounts for Mars¡¦ enigmatic surface erosion. This paper suggests 17 antifreeze compounds potentially present in Martian seepage groundwater. Given their liquid state and physical properties, triethylene glycol, diethylene glycol, ethylene glycol, and 1,3-propylene glycol are advanced as the most likely candidate compounds. This paper also explores how a mixing of glycol or glycerol with salts in the Martian seepage groundwater may have lowered water¡¦s freezing point and raised its boiling point, with consequences that created fluid gully and channel erosion. Ethylene glycol and related hydrocarbon compounds have been identified in Martian and other interstellar meteorites. We suggest that these compounds and their proportions to water be included for detection in future explorations.

  19. Utilizing avidity to improve antifreeze protein activity: a type III antifreeze protein trimer exhibits increased thermal hysteresis activity. (United States)

    Can, Özge; Holland, Nolan B


    Antifreeze proteins (AFPs) are ice growth inhibitors that allow the survival of several species living at temperatures colder than the freezing point of their bodily fluids. AFP activity is commonly defined in terms of thermal hysteresis, which is the difference observed for the solution freezing and melting temperatures. Increasing the thermal hysteresis activity of these proteins, particularly at low concentrations, is of great interest because of their wide range of potential applications. In this study, we have designed and expressed one-, two-, and three-domain antifreeze proteins to improve thermal hysteresis activity through increased binding avidity. The three-domain type III AFP yielded significantly greater activity than the one- and two-domain proteins, reaching a thermal hysteresis of >1.6 °C at a concentration of hysteresis activity.

  20. 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


    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.

  1. Construction of plant expression vector of Pseudopleuronectes americanus antifreeze protein gene

    Institute of Scientific and Technical Information of China (English)


    The Pseudopleuronectes americanus antifreeze protein gene was synthesized and control sequences were added such as 35S promoter and nos terminator that can facilitate the transcription and fi sequence and Kozak sequence that can improve the expression in translation level, the high expression cassette of antifreeze protein was constructed. This cassette was connected to pBI121.1 and finally got the high expression vector pBRTSAFP introduced into the maize callus. The expression of gus gene that linked to the antifreeze protein gene was detected, and the results was that the gus gene can express strongly and instantaneously.

  2. 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


    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.

  3. Dynamical mechanism of antifreeze proteins to prevent ice growth

    CERN Document Server

    Kutschan, B; Thoms, S


    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...

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

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    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.

  5. 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: [Gyeongsang National University, Department of Chemistry and Research Institute of Natural Science (Korea, Republic of)


    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.

  6. Cloning and expression of Tenebrio molitor antifreeze protein in Escherichia coli. (United States)

    Yue, Chang-Wu; Zhang, Yi-Zheng


    A novel antifreeze protein cDNA was cloned by RT-PCR from the larva of the yellow mealworm Tenebrio molitor. The coding fragment of 339 bp encodes a protein of 112 amino acid residues and was fused to the expression vectors pET32a and pTWIN1. The resulted expression plasmids were transformed into Escherischia coli strains BL21 (DE3), ER2566, and Origami B (DE3), respectively. Several strategies were used for expression of the highly disulfide-bonded beta-helix-contained protein with the activity of antifreeze in different expression systems. A protocol for production of refolded and active T. molitor antifreeze protein in bacteria was obtained.

  7. 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:,


    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)

  8. Nonequilibrium antifreeze peptides and the recrystallization of ice. (United States)

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


    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.

  9. Continuous production of CO2 hydrate slurry added antifreeze proteins

    Energy Technology Data Exchange (ETDEWEB)

    Tokunaga, Y.; Ota, M.; Murakami, K. [Tokyo Metropolitan Univ., Tokyo (Japan). Dept. of Mechanical Engineering; Ferdows, M. [Dhaka Univ., Dhaka (Bangladesh). Dept. of Mathematics; Endou, H. [Technova Co. Ltd., Tokyo (Japan). Dept. of Mechanical Engineering


    Ocean storage of carbon dioxide (CO{sub 2}) hydrate is possible in deep seas where low temperature and high pressure conditions exist. However, when hydrates are produced in large quantities, they can plug pipelines. The addition of antifreeze proteins (AFPs) can prevent hydrate crystals from forming. The hydrate may then behave like a slurry which can be transported from a production place to a place of storage with minimal pressure loss. This study developed a production method for a CO{sub 2} hydrate slurry and presented the prospect of the inhibition effect for CO{sub 2} hydrate formation by adding AFPs. It revealed the shift in induction time, the formation rate and the torque of the agitator under conditions of AFPs at 0.01 mg/ml. It was concluded that compared to pure water, the induction time for hydrate production increased 244 per cent, the formation rate decreased 76 per cent and the ratio of the torque decreased 48 per cent by adding AFPs. The AFPs rendered the hydrate particles small and well dispersed. It was concluded that type 3 AFPs can effectively inhibit the production of structure s1 type hydrates. 4 refs., 6 figs.

  10. Effect of Antifreeze Peptide Pretreatment on Ice Crystal Size, Drip Loss, Texture, and Volatile Compounds of Frozen Carrots. (United States)

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


    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.

  11. Cloning,sequencing and prokaryotic expression of cDNAs for antifreeze protein family from Beetle Tenebrio molitor

    Institute of Scientific and Technical Information of China (English)

    Zhongyuan LIU; Yun WANG; Guodong LU; Xianlei WANG; Fuchun ZHANG; Ji MA


    Partial cDNA sequences coding for antifreeze proteins in Tenebrio molitor were obtained by RT-PCR.Sequence analysis revealed nine putative cDNAs with a high degree of homology to Tenebrio molitor antifreeze protein genes published in GenBank.The recombinant pGEX-4T-l-tmafp-XJ430 was introduced into E.coli BL21 to induce a GST fusion protein by IPTG.SDS-PAGE analysis for the fusion protein shows a band of 38 kDa.pCDNA3- tmafp-XJ430 was injected into mice to generate antiserum which was later detected by indirect ELISA.The titer of the antibody was 1:2000.Western blot-ting analysis shows that the antiserum was specifically against the antifreeze protein.Our results laid the founda-tion for further studies on the properties and functions of insect antifreeze proteins.

  12. 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


    Antifreeze proteins (AFPs) are characterized by their ability to protect organisms from subfreezing temperatures by preventing tiny ice crystals in solution from growing as the solution is cooled below its freezing temperature. This inhibition of ice growth is called antifreeze activity, and in p......Antifreeze proteins (AFPs) are characterized by their ability to protect organisms from subfreezing temperatures by preventing tiny ice crystals in solution from growing as the solution is cooled below its freezing temperature. This inhibition of ice growth is called antifreeze activity......, and in particular, certain insect AFPs show very high antifreeze activity. Recent studies have shown AFPs to be promising candidates as green and environmentally benign inhibitors for gas hydrate formation. Here we show that an insect antifreeze protein from the longhorn beetle, Rhagium mordax (RmAFP1), the most...... potent protein yet found for freezing inhibition, can inhibit methane hydrates as effectively as the synthetic polymeric inhibitor polyvinylpyrrolidone (PVP). In high pressure rocking cell experiments, onset hydrate nucleation temperatures and growth profiles showed repeatable results. RmAFP1 clearly...

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

    DEFF Research Database (Denmark)

    Lørup Buch, Johannes; Ramløv, H


    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...... AFP could reliably be told apart from controls after only two minutes of recrystallisation. The goal of providing a fast, cheap and easy method for detecting antifreeze proteins in solution was met, and further development of the system can be followed at

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

    DEFF Research Database (Denmark)

    Kristiansen, E; Ramløv, Hans; Højrup, Peter


    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...

  15. 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


    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.

  16. 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


    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).

  17. An open source cryostage and software analysis method for detection of antifreeze activity. (United States)

    Buch, J L; Ramløv, H


    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 AFP could reliably be told apart from controls after only two minutes of recrystallisation. The goal of providing a fast, cheap and easy method for detecting antifreeze proteins in solution was met, and further development of the system can be followed at

  18. Evaluation of anti-freeze viscosity modifier for potential external tank applications (United States)

    Lynn, R. O. L.


    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.

  19. Antifreeze protein modulates cell survival during cryopreservation: mediation through influence on ice crystal growth.


    Carpenter, J F; Hansen, T N


    Antifreeze proteins (AFPs) are extremely efficient at inhibiting ice recrystallization in frozen solutions. Knight and Duman [Knight, C. A. & Duman, J. G. (1986) Cryobiology 23, 256-263] have proposed that this may be an important function of the proteins in freeze-tolerant organisms. We have tested this proposal in vitro by characterizing the influence of AFP on the recovery of cryopreserved cells, which often can survive cooling and yet subsequently be damaged by ice crystal growth during w...

  20. Snow-mold-induced apoplastic proteins in winter rye leaves lack antifreeze activity (United States)

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


    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.

  1. Role of ice nucleation and antifreeze activities in pathogenesis and growth of snow molds. (United States)

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


    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.

  2. Intermolecular interaction studies of winter flounder antifreeze protein reveal the existence of thermally accessible binding state. (United States)

    Nguyen, Dat H; Colvin, Michael E; Yeh, Yin; Feeney, Robert E; Fink, William H


    The physical nature underlying intermolecular interactions between two rod-like winter flounder antifreeze protein (AFP) molecules and their implication for the mechanism of antifreeze function are examined in this work using molecular dynamics simulations, augmented with free energy calculations employing a continuum solvation model. The energetics for different modes of interactions of two AFP molecules is examined in both vacuum and aqueous phases along with the water distribution in the region encapsulated by two antiparallel AFP backbones. The results show that in a vacuum two AFP molecules intrinsically attract each other in the antiparallel fashion, where their complementary charge side chains face each other directly. In the aqueous environment, this attraction is counteracted by both screening and entropic effects. Therefore, two nearly energetically degenerate states, an aggregated state and a dissociated state, result as a new aspect of intermolecular interaction in the paradigm for the mechanism of action of AFP. The relevance of these findings to the mechanism of function of freezing inhibition in the context of our work on Antarctic cod antifreeze glycoprotein (Nguyen et al., Biophysical Journal, 2002, Vol. 82, pp. 2892-2905) is discussed.

  3. Cloning and expression of a novel antifreeze protein AFP72 from the beetle Tenebrio molitor. (United States)

    Yan, Qing-Hua; Yang, Li; Wang, Qing; Zhang, Hui-Rong; Shao, Qiang


    A novel antifreeze protein AFP72 cDNA (GenBbank accession No. AY929389) was obtained by RT-PCR from Tenebrio molitor. The 216 bp fragment encodes a protein of 72 amino acid residues. Sequence analysis revealed that the cDNA displays a high degree of homology with T. molitor antifreeze proteins, ranging up to 90.78%. Recombinant plasmids pMAL-p2X-afp72 and pMAL-c2X-afp72 were transferred into E. coil TBI to induce a MBP fusion protein by IPTG. The target fusion protein was released from the periplasm and cytoplasm by the cold osmotic shock procedure and sonication respectively. The content of the fusion protein came up to 38.9 and 41.5% of the total dissolved protein, respectively. The fusion protein was purified through an amylose affinity column, and incised by factor Xa. Molecular sieve chromatography was used to achieve a high state of purity of the target protein. The purified target protein displayed a single band in SDS-PAGE. The fusion protein was shown to increase resistance to low temperatures in bacteria. This finding could help in further investigations of the properties and function of antifreeze proteins.

  4. A low molecular weight peptide from snow mold with epitopic homology to the winter flounder antifreeze protein. (United States)

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


    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.

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

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


    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.

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

    Directory of Open Access Journals (Sweden)

    Runtao Yang


    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.

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

    Directory of Open Access Journals (Sweden)

    Srisulak Dheeranupattana


    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.

  8. Induced ice melting by the snow flea antifreeze protein from molecular dynamics simulations. (United States)

    Todde, Guido; Whitman, Christopher; Hovmöller, Sven; Laaksonen, Aatto


    Antifreeze proteins (AFP) allow different life forms, insects as well as fish and plants, to survive in subzero environments. AFPs prevent freezing of the physiological fluids. We have studied, through molecular dynamics simulations, the behavior of the small isoform of the AFP found in the snow flea (sfAFP), both in water and at the ice/water interface, of four different ice planes. In water at room temperature, the structure of the sfAFP is found to be slightly unstable. The loop between two polyproline II helices has large fluctuations as well as the C-terminus. Torsional angle analyses show a decrease of the polyproline II helix area in the Ramachandran plots. The protein structure instability, in any case, should not affect its antifreeze activity. At the ice/water interface the sfAFP triggers local melting of the ice surface. Bipyramidal, secondary prism, and prism ice planes melt in the presence of AFP at temperatures below the melting point of ice. Only the basal plane is found to be stable at the same temperatures, indicating an adsorption of the sfAFP on this ice plane as confirmed by experimental evidence.

  9. Antifreeze and cryoprotective activities of ice-binding collagen peptides from pig skin. (United States)

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


    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.

  10. Ice-surface adsorption enhanced colligative effect of antifreeze proteins in ice growth inhibition (United States)

    Mao, Yougang; Ba, Yong


    This Communication describes a mechanism to explain antifreeze protein's function to inhibit the growth of ice crystals. We propose that the adsorption of antifreeze protein (AFP) molecules on an ice surface induces a dense AFP-water layer, which can significantly decrease the mole fraction of the interfacial water and, thus, lower the temperature for a seed ice crystal to grow in a super-cooled AFP solution. This mechanism can also explain the nearly unchanged melting point for the ice crystal due to the AFP's ice-surface adsorption. A mathematical model combining the Langmuir theory of adsorption and the colligative effect of thermodynamics has been proposed to find the equilibrium constants of the ice-surface adsorptions, and the interfacial concentrations of AFPs through fitting the theoretical curves to the experimental thermal hysteresis data. This model has been demonstrated by using the experimental data of serial size-mutated beetle Tenebrio molitor (Tm) AFPs. It was found that the AFP's ice-surface adsorptions could increase the interfacial AFP's concentrations by 3 to 4 orders compared with those in the bulk AFP solutions.

  11. 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


    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.

  12. The Surface of Ice in the presence of Antifreeze Proteins studied by Atomic Force Microscopy (United States)

    Zepeda, Salvador; Orme, Christine; Yeh, Yin


    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.

  13. Raman spectroscopy of antifreeze glycoproteins and their interaction with various substrates (United States)

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


    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.

  14. Antifreeze Activity of Xylomannan from the Mycelium and Fruit Body of Flammulina velutipes. (United States)

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


    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.

  15. Structural basis for antifreeze activity of ice-binding protein from arctic yeast. (United States)

    Lee, Jun Hyuck; Park, Ae Kyung; Do, Hackwon; Park, Kyoung Sun; Moh, Sang Hyun; Chi, Young Min; Kim, Hak Jun


    Arctic yeast Leucosporidium sp. produces a glycosylated ice-binding protein (LeIBP) with a molecular mass of ∼25 kDa, which can lower the freezing point below the melting point once it binds to ice. LeIBP is a member of a large class of ice-binding proteins, the structures of which are unknown. Here, we report the crystal structures of non-glycosylated LeIBP and glycosylated LeIBP at 1.57- and 2.43-Å resolution, respectively. Structural analysis of the LeIBPs revealed a dimeric right-handed β-helix fold, which is composed of three parts: a large coiled structural domain, a long helix region (residues 96-115 form a long α-helix that packs along one face of the β-helix), and a C-terminal hydrophobic loop region ((243)PFVPAPEVV(251)). Unexpectedly, the C-terminal hydrophobic loop region has an extended conformation pointing away from the body of the coiled structural domain and forms intertwined dimer interactions. In addition, structural analysis of glycosylated LeIBP with sugar moieties attached to Asn(185) provides a basis for interpreting previous biochemical analyses as well as the increased stability and secretion of glycosylated LeIBP. We also determined that the aligned Thr/Ser/Ala residues are critical for ice binding within the B face of LeIBP using site-directed mutagenesis. Although LeIBP has a common β-helical fold similar to that of canonical hyperactive antifreeze proteins, the ice-binding site is more complex and does not have a simple ice-binding motif. In conclusion, we could identify the ice-binding site of LeIBP and discuss differences in the ice-binding modes compared with other known antifreeze proteins and ice-binding proteins.

  16. Assessing the ability of a short fluorinated antifreeze glycopeptide and a fluorinated carbohydrate derivative to inhibit ice recrystallization. (United States)

    Chaytor, Jennifer L; Ben, Robert N


    A short fluorinated antifreeze glycopeptide (2) was synthesized and evaluated for ice recrystallization inhibition (IRI) activity. The activity of 2 was compared to native biological antifreeze AFGP 8 and a rationally designed C-linked AFGP analogue (OGG-Gal, 1). In addition, a simple fluorinated galactose derivative was prepared and its IRI activity was compared to non-fluorinated compounds. The results from this study suggest that the stereochemistry at the anomeric position in the carbohydrate plays a role in imparting ice recrystallization inhibition activity and that incorporation of hydrophobic groups such as fluorine atoms cause a decrease in IRI activity. These observations are consistent with the theory that fluorine atoms increase ordering of bulk water resulting in a decrease of IRI activity, supporting our previously proposed mechanism of ice recrystallization inhibition.

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

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


    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.

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

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


    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.

  19. Solution conformation of C-linked antifreeze glycoprotein analogues and modulation of ice recrystallization. (United States)

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


    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

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

    Directory of Open Access Journals (Sweden)

    Hyun-Cheol Kim


    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.

  1. New insights into ice growth and melting modifications by antifreeze proteins. (United States)

    Bar-Dolev, Maya; Celik, Yeliz; Wettlaufer, J S; Davies, Peter L; Braslavsky, Ido


    Antifreeze proteins (AFPs) evolved in many organisms, allowing them to survive in cold climates by controlling ice crystal growth. The specific interactions of AFPs with ice determine their potential applications in agriculture, food preservation and medicine. AFPs control the shapes of ice crystals in a manner characteristic of the particular AFP type. Moderately active AFPs cause the formation of elongated bipyramidal crystals, often with seemingly defined facets, while hyperactive AFPs produce more varied crystal shapes. These different morphologies are generally considered to be growth shapes. In a series of bright light and fluorescent microscopy observations of ice crystals in solutions containing different AFPs, we show that crystal shaping also occurs during melting. In particular, the characteristic ice shapes observed in solutions of most hyperactive AFPs are formed during melting. We relate these findings to the affinities of the hyperactive AFPs for the basal plane of ice. Our results demonstrate the relation between basal plane affinity and hyperactivity and show a clear difference in the ice-shaping mechanisms of most moderate and hyperactive AFPs. This study provides key aspects associated with the identification of hyperactive AFPs.

  2. CryoProtect: A Web Server for Classifying Antifreeze Proteins from Nonantifreeze Proteins

    Directory of Open Access Journals (Sweden)

    Reny Pratiwi


    Full Text Available Antifreeze protein (AFP is an ice-binding protein that protects organisms from freezing in extremely cold environments. AFPs are found across a diverse range of species and, therefore, significantly differ in their structures. As there are no consensus sequences available for determining the ice-binding domain of AFPs, thus the prediction and characterization of AFPs from their sequence is a challenging task. This study addresses this issue by predicting AFPs directly from sequence on a large set of 478 AFPs and 9,139 non-AFPs using machine learning (e.g., random forest as a function of interpretable features (e.g., amino acid composition, dipeptide composition, and physicochemical properties. Furthermore, AFPs were characterized using propensity scores and important physicochemical properties via statistical and principal component analysis. The predictive model afforded high performance with an accuracy of 88.28% and results revealed that AFPs are likely to be composed of hydrophobic amino acids as well as amino acids with hydroxyl and sulfhydryl side chains. The predictive model is provided as a free publicly available web server called CryoProtect for classifying query protein sequence as being either AFP or non-AFP. The data set and source code are for reproducing the results which are provided on GitHub.

  3. Ancient climate change, antifreeze, and the evolutionary diversification of Antarctic fishes. (United States)

    Near, Thomas J; Dornburg, Alex; Kuhn, Kristen L; Eastman, Joseph T; Pennington, Jillian N; Patarnello, Tomaso; Zane, Lorenzo; Fernández, Daniel A; Jones, Christopher D


    The Southern Ocean around Antarctica is among the most rapidly warming regions on Earth, but has experienced episodic climate change during the past 40 million years. It remains unclear how ancient periods of climate change have shaped Antarctic biodiversity. The origin of antifreeze glycoproteins (AFGPs) in Antarctic notothenioid fishes has become a classic example of how the evolution of a key innovation in response to climate change can drive adaptive radiation. By using a time-calibrated molecular phylogeny of notothenioids and reconstructed paleoclimate, we demonstrate that the origin of AFGP occurred between 42 and 22 Ma, which includes a period of global cooling approximately 35 Ma. However, the most species-rich lineages diversified and evolved significant ecological differences at least 10 million years after the origin of AFGPs, during a second cooling event in the Late Miocene (11.6-5.3 Ma). This pattern indicates that AFGP was not the sole trigger of the notothenioid adaptive radiation. Instead, the bulk of the species richness and ecological diversity originated during the Late Miocene and into the Early Pliocene, a time coincident with the origin of polar conditions and increased ice activity in the Southern Ocean. Our results challenge the current understanding of the evolution of Antarctic notothenioids suggesting that the ecological opportunity that underlies this adaptive radiation is not linked to a single trait, but rather to a combination of freeze avoidance offered by AFGPs and subsequent exploitation of new habitats and open niches created by increased glacial and ice sheet activity.

  4. Expression and characterization of an antifreeze protein from the perennial rye grass, Lolium perenne. (United States)

    Lauersen, Kyle J; Brown, Alan; Middleton, Adam; Davies, Peter L; Walker, Virginia K


    Antifreeze proteins (AFP) are an evolutionarily diverse class of stress response products best known in certain metazoans that adopt a freeze-avoidance survival strategy. The perennial ryegrass, Lolium perenne (Lp), cannot avoid winter temperatures below the crystallization point and is thought to use its LpAFP in a freeze-tolerant strategy. In order to examine properties of LpAFP in relation to L. perenne's life history, cDNA cloning, recombinant protein characterization, ice-binding activities, gene copy number, and expression responses to low temperature were examined. Transcripts, encoded by only a few gene copies, appeared to increase in abundance after diploid plants were transferred to 4°C for 1-2 days, and in parallel with the ice recrystallization inhibition activities. Circular dichroism spectra of recombinant LpAFP showed three clear folding transition temperatures including one between 10 and 15°C, suggesting to us that folding modifications of the secreted AFP could allow the targeted degradation of the protein in planta when temperatures increase. Although LpAFP showed low thermal hysteresis activity and partitioning into ice, it was similar to AFPs from freeze-avoiding organisms in other respects. Therefore, the type of low temperature resistance strategy adopted by a particular species may not depend on the type of AFP. The independence of AFP sequence and life-history has practical implications for the development of genetically-modified crops with enhanced freeze tolerance.

  5. Determining the ice-binding planes of antifreeze proteins by fluorescence-based ice plane affinity. (United States)

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


    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.

  6. Dendrimer-Linked Antifreeze Proteins Have Superior Activity and Thermal Recovery. (United States)

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


    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.

  7. Low thermodynamic but high kinetic stability of an antifreeze protein from Rhagium mordax. (United States)

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


    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.

  8. Isolation and characterization of type I antifreeze proteins from cunner, Tautogolabrus adspersus, order Perciformes. (United States)

    Hobbs, Rod S; Shears, Margaret A; Graham, Laurie A; Davies, Peter L; Fletcher, Garth L


    Antifreeze proteins (AFPs) are produced by many species of teleost fish that inhabit potentially lethal ice-laden seawater and afford them protection from freezing. To date type I AFPs have been fully characterized in two teleost orders: Pleuronectiformes and Scorpaeniformes. In this study, we report the isolation and complete characterization of a type I AFP present in fish from a third order: cunner (Tautogolabrus adspersus), order Perciformes (family Labridae). This protein was purified from blood plasma and found to belong to what is now known as classical type I AFP with their small size (mass 4095.16 Da), alanine richness (> 57 mol%), high α-helicity (> 99%) with the ability to undergo reversible thermal denaturation, 11 amino acid (ThrX(10)) repeat regions within the primary structure, the capacity to impart a hexagonal bipyramidal shaping to ice crystals and the conservation of an ice-binding site found in many of the other type I AFPs. Partial de novo sequencing of the plasma AFP accounted for approximately half of the peptide mass. Sequencing of a combined liver and skin cDNA library indicated that the protein is produced without a signal sequence. In addition the translated product of the AFP cDNA suggests that it codes for the AFP isolated from plasma. These results further solidify the hypothesis that type I AFPs are multiphyletic in origin and suggest that they represent remarkable examples of convergent evolution within three orders of teleost fish.

  9. Antifreeze proteins in the primary urine of larvae of the beetle Dendroides canadensis. (United States)

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


    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.

  10. Hydration behavior at the ice-binding surface of the Tenebrio molitor antifreeze protein. (United States)

    Midya, Uday Sankar; Bandyopadhyay, Sanjoy


    Molecular dynamics (MD) simulations have been carried out at two different temperatures (300 and 220 K) to study the conformational rigidity of the hyperactive Tenebrio molitor antifreeze protein (TmAFP) in aqueous medium and the structural arrangements of water molecules hydrating its surface. It is found that irrespective of the temperature the ice-binding surface (IBS) of the protein is relatively more rigid than its nonice-binding surface (NIBS). The presence of a set of regularly arranged internally bound water molecules is found to play an important role in maintaining the flat rigid nature of the IBS. Importantly, the calculations reveal that the strategically located hydroxyl oxygens of the threonine (Thr) residues in the IBS influence the arrangements of five sets of ordered waters around it on two parallel planes that closely resemble the basal plane of ice. As a result, these waters can register well with the ice basal plane, thereby allowing the IBS to preferentially bind at the ice interface and inhibit its growth. This provides a possible molecular reason behind the ice-binding activity of TmAFP at the basal plane of ice.

  11. 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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Engeler, L.; Salerno, B.


    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.

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

    Indian Academy of Sciences (India)

    K Sivakumar; S Balaji; Gangaradhakrishnan


    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.

  14. Revealing Surface Waters on an Antifreeze Protein by Fusion Protein Crystallography Combined with Molecular Dynamic Simulations. (United States)

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


    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.

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

    Directory of Open Access Journals (Sweden)

    Graham Laurie A


    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.

  16. 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.

  17. Antifreeze protein-induced superheating of ice inside Antarctic notothenioid fishes inhibits melting during summer warming. (United States)

    Cziko, Paul A; DeVries, Arthur L; Evans, Clive W; Cheng, Chi-Hing Christina


    Antifreeze proteins (AFPs) of polar marine teleost fishes are widely recognized as an evolutionary innovation of vast adaptive value in that, by adsorbing to and inhibiting the growth of internalized environmental ice crystals, they prevent death by inoculative freezing. Paradoxically, systemic accumulation of AFP-stabilized ice could also be lethal. Whether or how fishes eliminate internal ice is unknown. To investigate if ice inside high-latitude Antarctic notothenioid fishes could melt seasonally, we measured its melting point and obtained a decadal temperature record from a shallow benthic fish habitat in McMurdo Sound, Antarctica. We found that AFP-stabilized ice resists melting at temperatures above the expected equilibrium freezing/melting point (eqFMP), both in vitro and in vivo. Superheated ice was directly observed in notothenioid serum samples and in solutions of purified AFPs, and ice was found to persist inside live fishes at temperatures more than 1 °C above their eqFMP for at least 24 h, and at a lower temperature for at least several days. Field experiments confirmed that superheated ice occurs naturally inside wild fishes. Over the long-term record (1999-2012), seawater temperature surpassed the fish eqFMP in most summers, but never exceeded the highest temperature at which ice persisted inside experimental fishes. Thus, because of the effects of AFP-induced melting inhibition, summer warming may not reliably eliminate internal ice. Our results expose a potentially antagonistic pleiotropic effect of AFPs: beneficial freezing avoidance is accompanied by melting inhibition that may contribute to lifelong accumulation of detrimental internal ice crystals.

  18. 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;


    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...

  19. Gold Nanoparticle Aggregation as a Probe of Antifreeze (Glyco) Protein-Inspired Ice Recrystallization Inhibition and Identification of New IRI Active Macromolecules. (United States)

    Mitchell, Daniel E; Congdon, Thomas; Rodger, Alison; Gibson, Matthew I


    Antifreeze (glyco)proteins are found in polar fish species and act to slow the rate of growth of ice crystals; a property known as ice recrystallization inhibition. The ability to slow ice growth is of huge technological importance especially in the cryopreservation of donor cells and tissue, but native antifreeze proteins are often not suitable, nor easily available. Therefore, the search for new materials that mimic this function is important, but currently limited by the low-throughout assays associated with the antifreeze properties. Here 30 nm gold nanoparticles are demonstrated to be useful colorimetric probes for ice recrystallization inhibition, giving a visible optical response and is compatible with 96 well plates for high-throughout studies. This method is faster, requires less infrastructure, and has easier interpretation than the currently used 'splat' methods. Using this method, a series of serum proteins were identified to have weak, but specific ice recrystallization inhibition activity, which was removed upon denaturation. It is hoped that high-throughput tools such as this will accelerate the discovery of new antifreeze mimics.


    Directory of Open Access Journals (Sweden)

    Ricardo Vera Bravo


    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.

  1. Structure of solvation water around the active and inactive regions of a type III antifreeze protein and its mutants of lowered activity (United States)

    Grabowska, Joanna; Kuffel, Anna; Zielkiewicz, Jan


    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

  2. 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


    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...

  3. Characterization of threonine side chain dynamics in an antifreeze protein using natural abundance {sup 13}C NMR spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Daley, Margaret E.; Sykes, Brian D. [University of Alberta, Department of Biochemistry, CIHR Group in Protein Structure and Function and Protein Engineering Network of Centres of Excellence (Canada)


    The dynamics of threonine side chains of the Tenebrio molitor antifreeze protein (TmAFP) were investigated using natural abundance {sup 13}C NMR. In TmAFP, the array of threonine residues on one face of the protein is responsible for conferring its ability to bind crystalline ice and inhibit its growth. Heteronuclear longitudinal and transverse relaxation rates and the {sup 1}H-{sup 13}C NOE were determined in this study. The C{alpha}H relaxation measurements were compared to the previously measured {sup 15}N backbone parameters and these are found to be in agreement. For the analysis of the threonine side chain motions, the model of restricted rotational diffusion about the {chi}{sub 1} dihedral angle was employed [London and Avitabile (1978) J. Am. Chem. Soc., 100, 7159-7165]. We demonstrate that the motion experienced by the ice binding threonine side chains is highly restricted, with an approximate upper limit of less than {+-}25 deg.

  4. 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

  5. Discussion on applying an analytical method to optimize the anti-freeze design parameters for underground water pipelines in seasonally frozen areas

    Institute of Scientific and Technical Information of China (English)

    Ji Chen; JingYi Zhao; Kun Li; Yu Sheng


    Adopting the quasi-three-dimensional (Quasi-3D) numerical method to optimize the anti-freeze design parameters of an underground pipeline usually involves heavy numerical calculations. Here, the fitting formulae between the safe con-veyance distance (SCD) of a water pipeline and six influencing factors are established based on the lowest water temper-ature (LWT) along the pipeline axis direction. With reference to the current widely used anti-freeze design approaches for underground pipelines in seasonally frozen areas, this paper first analyzes the feasibility of applying the maximum frozen penetration (MFP) instead of the mean annual ground surface temperature (MAGST) and soil water content (SWC) to calculate the SCD. The results show that the SCD depends on the buried depth if the MFP is fixed and the variation of the MAGST and SWC combination does not significantly change the SCD. A comprehensive formula for the SCD is estab-lished based on the relationships between the SCD and several primary influencing factors and the interaction among them. This formula involves five easy-to-access parameters:the MFP, buried depth, pipeline diameter, flow velocity, and inlet water temperature. A comparison between the analytical method and the numerical results based on the Quasi-3D method indicates that the two methods are in good agreement overall. The analytic method can be used to optimize the anti-freeze design parameters of underground water pipelines in seasonally frozen areas under the condition of a 1.5 safety coefficient.

  6. X-ray Structure of Snow Flea Antifreeze Protein Determined by Racemic Crystallization of Synthetic Protein Enantiomers

    Energy Technology Data Exchange (ETDEWEB)

    Pentelute, Brad L.; Gates, Zachary P.; Tereshko, Valentina; Dashnau, Jennifer L.; Vanderkooi, Jane M.; Kossiakoff, Anthony A.; Kent, Stephen B.H. (UPENN); (UC)


    Chemical protein synthesis and racemic protein crystallization were used to determine the X-ray structure of the snow flea antifreeze protein (sfAFP). Crystal formation from a racemic solution containing equal amounts of the chemically synthesized proteins d-sfAFP and l-sfAFP occurred much more readily than for l-sfAFP alone. More facile crystal formation also occurred from a quasi-racemic mixture of d-sfAFP and l-Se-sfAFP, a chemical protein analogue that contains an additional -SeCH2- moiety at one residue and thus differs slightly from the true enantiomer. Multiple wavelength anomalous dispersion (MAD) phasing from quasi-racemate crystals was then used to determine the X-ray structure of the sfAFP protein molecule. The resulting model was used to solve by molecular replacement the X-ray structure of l-sfAFP to a resolution of 0.98 {angstrom}. The l-sfAFP molecule is made up of six antiparallel left-handed PPII helixes, stacked in two sets of three, to form a compact brick-like structure with one hydrophilic face and one hydrophobic face. This is a novel experimental protein structure and closely resembles a structural model proposed for sfAFP. These results illustrate the utility of total chemical synthesis combined with racemic crystallization and X-ray crystallography for determining the unknown structure of a protein.

  7. Transcriptomic and proteomic analyses on the supercooling ability and mining of antifreeze proteins of the Chinese white wax scale insect. (United States)

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


    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.

  8. Ice-binding site of snow mold fungus antifreeze protein deviates from structural regularity and high conservation. (United States)

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


    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.

  9. 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


    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.

  10. Oscillations and accelerations of ice crystal growth rates in microgravity in presence of antifreeze glycoprotein impurity in supercooled water (United States)

    Furukawa, Yoshinori; Nagashima, Ken; Nakatsubo, Shun-ichi; Yoshizaki, Izumi; Tamaru, Haruka; Shimaoka, Taro; Sone, Takehiko; Yokoyama, Etsuro; Zepeda, Salvador; Terasawa, Takanori; Asakawa, Harutoshi; Murata, Ken-ichiro; Sazaki, Gen


    The free growth of ice crystals in supercooled bulk water containing an impurity of glycoprotein, a bio-macromolecule that functions as ‘antifreeze’ in living organisms in a subzero environment, was observed under microgravity conditions on the International Space Station. We observed the acceleration and oscillation of the normal growth rates as a result of the interfacial adsorption of these protein molecules, which is a newly discovered impurity effect for crystal growth. As the convection caused by gravity may mitigate or modify this effect, secure observations of this effect were first made possible by continuous measurements of normal growth rates under long-term microgravity condition realized only in the spacecraft. Our findings will lead to a better understanding of a novel kinetic process for growth oscillation in relation to growth promotion due to the adsorption of protein molecules and will shed light on the role that crystal growth kinetics has in the onset of the mysterious antifreeze effect in living organisms, namely, how this protein may prevent fish freezing. PMID:28262787

  11. Gene expression of different antifreeze proteins of Tenebrio molitor in response to cold acclimation%黄粉虫不同抗冻蛋白基因家族成员的低温应激表达

    Institute of Scientific and Technical Information of China (English)

    冯云甲; 徐洪富; 王宪辉


    黄粉虫Tenebrio molitorL.抗冻蛋白基因家族有多个成员,其氨基酸数量和蛋白结构存在差异.尽管有报道发现冷驯化后这些抗冻蛋白的表达量会升高,但不同家族成员是否存在功能分化尚不清楚.本研究中,检测了冷驯化对低温死亡率的效应和对不同类型的抗冻蛋白家族成员基因表达量的影响.结果表明,冷驯化可以显著降低黄粉虫幼虫的低温死亡率和提高不同类型抗冻蛋白基因的表达量.其中,长的抗冻蛋白和低温死亡率的相关关系最为明显.说明不同的抗冻蛋白家族成员的功能有明显的分化,为进一步理解抗冻蛋白的活性和利用抗冻蛋白提供了新的认识.%The Tenebrio molitor L. antifreeze protein gene family has multiple members which differ in the number of amino acids and protein structure. The mRNA level of antifreeze proteins is enhanced by cold conditions but functional differentiation of different members of this family is not clear. In this study, we examined the effects of mortality from cold exposure on the gene expression of different types of antifreeze protein members in the family. The results show that cold acclimation can significantly reduce larval mortality and improve expression of the antifreeze protein gene. The longest antifreeze protein is most important to low-temperature-related mortality. This result indicates that the function of different antifreeze protein family members differs and provides new insights for the use of antifreeze proteins and antifreeze protein activity.

  12. The effects of antifreeze peptide III (AFP) and insulin transferrin selenium (ITS) on cryopreservation of chimpanzee (Pan troglodytes) spermatozoa. (United States)

    Younis, A I; Rooks, B; Khan, S; Gould, K G


    We investigated the effects of antifreeze peptides (AFP) and insulin transferrin selenium (ITS) on the motility and membrane integrity of chimpanzee (Pan troglodytes) spermatozoa after chilling (0-5 degrees C) and thawing. The effects of three thawing procedures, in the presence or absence of AFP and ITS, on sperm motility and on the status of the plasma membrane and acrosome were also examined. During chilling, AFP and ITS seem mildly cytotoxic, as the progressive motility and velocity (curvilinear and straight line) declined significantly at AFP concentrations of 1, 10, and 100 microg/ml and at ITS concentrations of 1 and 10 microg/ml. However, at a concentration of 100 microg/ml, ITS was able to protect sperm during short-term hypothermic storage. Addition of AFP or ITS at 100 microg/ml to test egg yolk-glycerol extender during freezing significantly (P < 0.05) increased postthaw motility, plasma membrane integrity, and acrosome integrity. The mean (+/-SE) motility recovery rate increased from 28.9 +/- 3.9%, for the untreated control, to 59.2 +/- 5.8% and 67.8 +/- 7.4%, for ITS and AFP, respectively. The effects of the thawing procedure were influenced by the presence of AFP during the freezing cycle. An improved motility recovery rate of 67 +/- 4.2% was obtained when chimpanzee sperm frozen in test egg yolk-glycerol extender supplemented with AFP were thawed rapidly at 37 degrees C, compared to 47 +/- 5.2% and 44 +/- 8.2% for slow (23 degrees C) and ultrarapid (75 degrees C) thawing, respectively. The motility recovery after thawing of ITS-treated semen at 23 degrees C, 37 degrees C, or 75 degrees C was not significantly different. Semen frozen without AFP or ITS and thawed at 75 degrees C was seriously (P < 0.05) damaged. This study provides evidence that AFP- or ITS-supplemented semen extender improves postthaw sperm motility in the chimpanzee.

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

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


    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.

  14. Tissue specific expression of antifreeze protein and growth hormone transgenes driven by the ocean pout (Macrozoarces americanus) antifreeze protein OP5a gene promoter in Atlantic salmon (Salmo salar). (United States)

    Hobbs, Rod S; Fletcher, Garth L


    Previous research aimed at producing genetically improved salmon broodstock for aquaculture led to the creation of two lines of transgenic Atlantic salmon using gene constructs that were derived in part from the ocean pout OP5a antifreeze protein (AFP) gene. One of the lines was produced using an OP5a AFP gene in which the 5' region of the promoter was removed (termed t-OP5a-AFP), and the other line contains a growth hormone (GH) transgene (EO-1alpha) that consists of a chinook salmon GH cDNA driven by a truncated OP5a AFP promoter that is almost identical to that of the t-OP5a-AFP construct. The similarity of the promoter regions of these transgenes provided an opportunity to evaluate their tissue specific expression patterns. Expression of mRNA was evaluated using Northern blot and RT-PCR techniques. The results demonstrate that the AFP and GH trangenes were expressed in almost all body tissues, suggesting that the promoter region of the OP5a AFP gene lacks tissue specific elements. Northern analysis revealed that expression of the t-OP5a-AFP gene was considerably greater than that of the EO-1alpha GH transgene. Only the spleen tissue of the GH transgenics showed a visible band of hybridization. In contrast clear bands of hybridization were evident in all tissues, except for blood cells, of the AFP transgenics with heart, liver and brain tissue showing the highest levels of mRNA expression. This higher level of expression could be attributable to the presence of introns in the t-OP5a-AFP transgene. Since the GH transgenic salmon grow considerably faster than non-transgenics the low levels of GH transgene expression in this line were clearly sufficient to produce the desired rapid growth phenotype. In contrast the levels of AFP expression were inadequate to impart any improvement in the freeze resistance of the AFP transgenic salmon.

  15. 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


    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.

  16. 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.

  17. 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


    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......, are here characterized and their crystal structures determined. We conclude that the higher activity of the QAE1 isoforms cannot be attributed to single residues, but rather a combination of structural effects. Furthermore both ZvAFP6 and ZvAFP13 crystal structures have water molecules around T18...... equivalent to the tetrahedral-like waters previously identified in a neutron crystal structure. Interestingly, ZvAFP6 forms dimers in the crystal, with a significant dimer interface. The presence of ZvAFP6 dimers was confirmed in solution by native electrophoresis and gel filtration. To our knowledge...

  18. 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


    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.

  19. Optimization of a biolistic transformation system for transfer of antifreeze gene KN2 and the bar herbicide resistance gene in common wheat. (United States)

    Cai, L; Sun, D F; Sun, G L


    We studied the effects of different media for callus induction and differentiation, and pre-culture period of immature wheat embryo culture on biolistic transformation efficiency for including antifreeze gene KN2 and bar conferring resistance to the herbicide bialaphos. The percentage of plantlets generated from induction and differentiation media without Cu2+ was lower than those cultured on differentiation media with Cu2+ (71.15%) or induction media with Cu2+ (68.45%) and both induction and differentiation media with Cu2+ (52.17%). The combinations of Nor medium for callus induction and Cu2+ medium for regeneration, and Cu2+ medium for induction and R medium for regeneration were superior for biolistic transformation. The calli induced on Cu2+ medium and pre-cultured for 4 d before biolistic transformation, and cultured on R medium after biolistic transformation produced the highest percentage (65%) of transgenic plantlets with the KN2 gene. Overall, about 50% plantlets regenerated from calli pre-cultured 4d before bombardment carried the KN2 gene; 44.7% of the plantlets carried the bar gene, which was higher than for any other treatment, followed by pre-culture 1d with 31.43% transformation rate for the KN2 gene and 20% transformation rate for the bar gene.

  20. 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


    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

  1. 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)



    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。

  2. 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


    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.

  3. 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


    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.

  4. 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


    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.

  5. 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


    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

  6. 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


    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

  7. 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


    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

  8. 天然抗冻多肽的制备、分离及细菌低温保护活性研究%Preparation, isolation and hypothermia protection activity on bacteria of natural antifreeze peptides

    Institute of Scientific and Technical Information of China (English)

    赵珺; 汪少芸; 李晓坤


    The gelatin of shark skin was extracted by hot water. The most appropriate protease and hydrolysis time were selected with the index of hypothermia protection activity on bacteria. Then the hydro-lyzate was added on to Sephadex G - 50 gel filtration chromatography and SP - Sephadex C - 25 strong cation exchange chromatography to acquire high activity fractions. The results indicated that the most appropriate protease is acid protease, and the hydrolysis condition is as follows, hydrolysis temperature 50 °C. pH 3.0, proportion of acid protease to substratum 3 000 U · g-1 per substratum, substratum concentration 3%. hydrolysis time 1 h. The cationic fraction termed P2 shows higher antifreeze activity after Sephadex G -50 gel filtration chromatography and SP - Sephadex C -25 strong cation exchange chromatography. The hypothermia protection assay shows that the survival rate of E. coll was 80. 8% when the concentration of peptide complexes was 500 μg · mL-1. The antifreeze peptides obtained after isolation shows higher antifreeze activity, and can be applied into food and medicine industry.%利用热水抽提法提取鲨鱼皮明胶,控制酶法水解条件制备天然抗冻多肽.以细菌低温保护活性为指标,筛选蛋白水解酶种类及酶解时间,利用SephadexG-50凝胶过滤色谱、SP-SephadexC-25强阳离子交换色谱等分离手段进行分离,得到细菌低温保护高活性组分.结果表明,酶解鲨鱼皮明胶得到高活性抗冻多肽的最适蛋白水解酶为酸性蛋白酶,酶解温度50℃、pH 3.0、酶/底物3000U ·g-1、底物浓度3%、酶解时间1h;经过Sephadex G-50凝胶过滤色谱、SP-Sephadex C-25强阳离子交换色谱等分离手段得到阳离子的P2组分,经过细菌低温保护测试,当浓度为500 μg·mL-1时,大肠杆菌的存活率达到80.8%.分离得到的抗冻多肽具有较高的抗冻活性,可望应用于食品、医药等产业中.

  9. 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. (United States)

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


    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.

  10. Study on Effect of Ventilation Tube Spacing on Thermal Performance of Cold Storage Floor Antifreezing Ventilation System%通风管间距对冷库地坪通风防冻系统传热性能影响的研究

    Institute of Scientific and Technical Information of China (English)

    贾景福; 郝满晋; 李建华


    The research aimed to investigate the effect of ventilation tube spacing on thermal performance of cold storage floor antifreezing ventilation system. A steady three-dimensional mathematical model of heat transfer was set up. The heat-transfer model was simplified reasonably. The definite conditions of the heat-transfer model were confirmed according to the heat-transfer process. The temperature field of this system were simulated and calculated by Phoenics under different kinds of working conditions, such as without circulating the ventilation system, with different tube spacing. The results showed that the effect of using mechanical antifreezing ventilation to cold storage floor was better. They also indicated the effect of ventilation tube spacing was greater on thermal performance of cold storage floor antifreezing ventilation system.%为了研究通风管间距对冷库地坪通风防冻系统传热性能的影响程度,建立了三维稳态传热数学模型,对传热模型进行了合理的简化,根据系统的传热过程确定了传热模型的定解条件,利用Phoenics软件对通风系统未启动和不同通风管间距下的传热模型分别进行了数值模拟分析.结果表明,对冷库地坪采取机械通风防冻的效果良好,通风管间距对冷库地坪通风防冻系统的传热性能有较大影响.

  11. 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


    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

  12. Cloning and bioinformatics analysis of antifreeze protein from Tenebrio molitor%黄粉甲抗冻蛋白基因克隆及生物信息学分析

    Institute of Scientific and Technical Information of China (English)

    任谦; 熊鸿燕; 朱才众; 张世界


    目的:获得黄粉甲抗冻蛋白基因afpTx及相关生物信息学资料.方法:从黄粉甲幼虫中提取总RNA,通过RT-PCR合成黄粉甲抗冻蛋白基因afpTx的eDNA片段,克隆入载体pMDl9-T,进行测序分析.酶切后将其亚克隆入表达栽体pET32a(+),构建表达质粒pET32a-afpllx,并转化到大肠杆菌DL21后提取质粒,双酶切鉴定.采用MEGA 4.0,BioEdit 5.0.6软件对本研究克隆的抗冻蛋白基因afpTx进行氨基酸序列同源性变异及进化分析.结果:测序结果afpTx的cDNA长度为336 bp;编码112个氨基酸;酶切、电泳结果表明克隆和亚克隆获得成功.抗冻蛋白氨基酸序列相似性分析表明afpTx与GenBank上提交的23条黄粉甲抗冻蛋白的氨基酸序列平均一致性为88%;与11条赤翅甲抗冻蛋白氨基酸序列的平均一致性为67%,2种甲虫的平均一致性为63%.进化树分析结果显示黄粉甲与赤翅甲抗冻蛋白序列是同源序列.赤翅甲的序列趋异度显著大于黄粉甲抗冻蛋白基因序列.结论:成功克隆了本地黄粉甲的afpTx基因,该序列是GenBank上提交的黄粉甲与赤翅甲抗冻蛋白的同源序列.%AIM: To obtain sequence coding gene for the antifreeze proteins (AFP) from local Tenebrio molitor and to elucidate the related bioinformatics data. METHODS: After the total RNA was isolated, from the larva of Tenebrio molitor. cDNA encoding the afpTx was synthesized by RT-PCR, and the PCR products were inserted into the vector pMD19-T simple, which were subcloned into pET-32a( + ) and transformed into E. coli and identified with restriction enzyme analysis. Then the sequencing result was analyzed by MEGA 4. 0 and BioEdit 5. 0. 6 computer program for amino acid sequence homology and evolutionary variance. RESULTS: Sequencing result showed a correctly constructed vector that containing 336 bp antifreeze protein cDNA. Digestion and electrophoresis results confirmed that gene was successfully cloned and subcloned into pET32a

  13. Cloning and Sequencing of Antifreeze Protein Gene in Daucus carota var.sativus Hoffm Deutschl%胡萝卜Daucus carota 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


    以宁夏吴忠胡萝卜、陕西华县胡萝卜和陕西汉中胡萝卜3个地方品种为材料,用PCR(polymerase chain reaction)的方法克隆了中国胡萝卜的抗冻蛋白基因(afp),测定了其核苷酸序列,并和英国胡萝卜的afp序列进行了对比。在所测1004个核苷酸中,两变种碱基不同者有36个,占3.6%,其中无义突变21个,有义突变15个。按有义突变计,同源性为98.5%。%Three carrot cultivar Wuzhong Ningxia,Huaxian Shaanxi and Hanzhong Shaanxi were used as test material and antifreeze protein gene(a fp)of Chinese carrot(Daucus carota var.sativus Hoffm Deutschl)was clon ed and sequenced by PCR(polymerase chain reaction).Obtained sequence was compare d with that of British carrot(Daucus carota var.autumn King).There were 36 different bases in 1004 nucleotides(3.6%)between the two va-r ieties. Among the different bases there were 21 nonsense mutations and 15 sens e mutations.According to sense mutations,homology was 98.5%.

  14. 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


    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.

  15. Cloning of a carrot gene encoding antifreeze protein and construction of its plant expression vector%胡萝卜抗冻蛋白基因克隆及植物表达载体构建

    Institute of Scientific and Technical Information of China (English)

    尹明安; 崔鸿文; 樊代明; 郭立


    以胡萝卜品种Autumn King 的幼苗为材料,用CTAB法提取其基因组DNA,以PCR (Polymerase Chain Reaction)的方法在体外扩增出胡萝卜抗冻蛋白基因(afp),以pUCm-T Vector为载体构建成胡萝卜afp的克隆载体pTAF,用EcoRⅠ消化重组质粒pTAF使其线性化,再用DNA聚合酶Ⅰ Klenow大片段补平末端,然后用XbaⅠ消化,获得一末端粘,一末端平的目的片段(afp)。植物表达载体pBI121用XbaⅠ和SmaⅠ双酶切,获得一末端粘,一末端平的线性质粒。将目的片段与线性质粒在T4 DNA连接酶的作用下进行定向连接,构建成胡萝卜afp的植物表达载体pBAF。%Genomic DNA in the seedlings of carrot cultivar Autumn King was extracted with CTAB method.The carrot antifreeze protein gene (afp) was amplified by PCR(Polymerase Chain Reaction).Cloning vector pTAF of carrot afp was constru cted with pUCm-T Vector.PTAF was digested with EcoRⅠ and became linear.Its ends were filled with DNA Polymerase Ⅰ Klenow fragment.Then it was digested wi th XbaⅠ and a designed fragment (afp) with a cohesive end and a blunt end was released.Plant expression vector pBI121 was digested with XbaⅠ and SmaⅠand a linear plasmid with a cohesive end and a blunt end was obtained.The linear plasmid and the designed fragment (afp) were directively ligated with T4 DNA ligase,and the plant expression vector of carrot afp was constructed.

  16. 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)



    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

  17. 通风管管径对冷库地坪通风防冻系统传热性能影响的研究%Effect of ventilation tube diameter on heat transfer of cold storage floor antifreezing ventilation system

    Institute of Scientific and Technical Information of China (English)

    贾景福; 郝满晋; 赵建华


    为研究通风管管径对冷库地坪通风防冻系统传热性能的影响程度,建立三维稳态传热数学模型.对传热模型进行合理的简化,根据系统的传热过程确定传热模型的定解条件,利用PHOENICS软件对通风系统在不同通风管管径下的传热模型进行数值模拟分析.结果表明:通风管管径对冷库地坪通风防冻系统的传热性能有较大影响,指出通风管间距为1.5 m时的适当管径.%In order to investigate the effect of ventilation tube inside diameter on heat transfer of cold storage floor antifreezing ventilation system, a steady three-dimensional mathematical model of heat transfer was established. The heat-transfer model was reasonably simplified. The calculational conditions of the heat-transfer model were defined according to the heat-transfer process. The temperature fields of this system were simulated and calculated by PHOENICS under different tube inside diameter. The results showed that the effect of ventilation tube inside diameter was greater on thermal performance of cold storage floor antifreezing ventilation system. The proper tube inside diameter was pointed out for the cold storage floor with 1.5m tube spacing.

  18. The study on the anti-freeze performance of integral water repellent concrete with addition of silane emulsion%掺硅烷乳液制备整体防水混凝土的抗冻性试验研究

    Institute of Scientific and Technical Information of China (English)

    马志鸣; 赵铁军; 朱方之; 刘志强


    The experiment of freeze-thaw,frost-salt and capillary absorption after different freeze-thaw injury was earned out to study the performance of the concrete with addition of silane emulsion. The result indicated that the concrete with certain amount of silane emulsion had a low anli-freeze performance,and the anti-freeze performance decreased with the dosage of silane emulsion increased. But he concrete with addition of silane emulsion had a good water resistance performance under different freeze-thaw environment.%进行了掺硅烷乳液制备整体防水混凝土的水冻、盐冻以及不同冻融损伤后的毛细吸水试验.结果表明,在混凝土拌合料中掺加一定量的硅烷乳液,使混凝土的抗冻性降低,并且随着硅烷掺量增加,混凝土的抗冻性能变差.但是在不同的冻融损伤条件下,掺硅烷制备整体防水混凝土仍具有较好的抵抗水分侵入性能.

  19. 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.


    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.

  20. 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


    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 ...

  1. Antifreeze Production and Cold-Tolerance in Overwintering Purple Martin Fleas, Ceratophyllus idius Jordan and Rothschild. (United States)


    Bombyx mori, isotope [ 14C] studies showed that about 1/3 of the free glycerol pool came from lipids (Yaginuma and Yamashita 1980). However, the same...inactivated within the lipid phase of their cell membranes (Baust and Zachariassen 1983). Baust and Morrissey (1975) reported the possible masking of INAs...ambient or freezer-held regimens. Throughout the cooling process and all subsequent aspects of the project, fleas were held in total darkness

  2. Additifs anticongelants pour huiles de moteurs Antifreezing Additives for Motor Oils

    Directory of Open Access Journals (Sweden)

    Denis J.


    Full Text Available Cet article présente d'abord les principales familles chimiques d'additifs de congélation. Les paraffines normales restant dans l'huile après le déparaffinage cristallisent à basse température sous forme de fines lamelles constituées de plusieurs couches de molécules accolées, qui se superposent en spirales. Ces lamelles s'enchevêtrent en bloquant l'écoulement de l'huile. Les additifs s'interposent, soit par adsorption, soit par cocristallisation en favorisant la croissance des lamelles en épaisseur, ce qui les rend moins aptes à l'enchevêtrement. This article begins by describing the main chemical families of pour-point depressant additives. The normal paraffins remaining in the oil after dewaxing crystallize at low temperature in the form of very thin platelets made up of several layers of associated molecules that are superposed in spirals. These platelets become entangled and prevent the flow of oil. Additives work either by adsorption or by cocrystallization, enhancing the growth of lamella thickness, thus making them less capable of becoming entangled.

  3. 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.


    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.

  4. Integration of Nanofluids into Commercial Antifreeze Concentrates with ASTM D15 Corrosion Testing (United States)


    Corrosion Tests ASTM D 1384 Corrosion Test for Engine Coolants in Glassware and ASTM D 4340 Corrosion Test of Cast Aluminum Alloys in Engine Coolants...Saint-Gobain provided free nano slurry samples (300 nm, 360 nm, 13 mass% in water). 80 nm powders were purchased from NanoAmor. Diamond: 6 nm nano

  5. Calorimetric Analysis of Antifreeze Activity and the Absorption-inhibition Mechanism of Antifreeze Protein%抗冻蛋白活性的差示扫描量热测定及其吸附-抑制机制

    Institute of Scientific and Technical Information of China (English)

    任禾盛; 许娜飞; 华泽钊


    用差示扫描量热技术(DSC)测定了从黄粉虫(Tenebrio molitor)幼虫体内提取的抗冻蛋白(AFP)的活性,结果表明AFP活性随其浓度的增加及初始冰晶量的减少而增大,这与AFP对冰晶的吸附-抑制机制相一致.

  6. 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)



    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。

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

  8. Case Report of a Fatal Antifreeze Ingestion with a Record High Level and Impressive Renal Crystal Deposition (United States)


    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

  9. Hydration layer dynamics and association mechanisms of food and antifreeze proteins : A Molecular Dynamics and Transition Path Sampling study

    NARCIS (Netherlands)

    Brotzakis, Z.F.


    By the time the reader reads this line, billions of protein association events just occurred in our body, such as the ones regulating cell communication, signaling pathways, or in initiating a self-assembly processes, such as tissue fabrication, etc. The timescale of such transitions is slow, compar

  10. 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


    protein from Rhagium mordax (RmAFP) and biodegradable synthetic kinetic inhibitor Luvicap Bio. A systematic capillary dispersion method was used, and this method enhanced the ability to detect the effect of various inhibitors on hydrate formation with small quantities. The presence of RmAFP and Luvicap...... Bio influence (inhibit) the hydrate formation phenomena significantly. Luvicap Bio (relative strength compared to buffer: 13.3 degrees C) is stronger than RmAFP (9.8 degrees C) as a nucleation inhibitor. However, the presence RmAFP not only delays hydrate nucleation but also reduces the amount...... of hydrate formed (20%-30%) after nucleation significantly. Unlike RmAFP, Luvicap Bio promoted the amount of hydrate formed after nucleation. The superior hydrate growth inhibition capability and predictable hydrate melting behavior compared to complex, heterogeneous hydrate melting with Luvicap Bio shows...

  11. Effects of a type I antifreeze protein (AFP) on the melting of frozen AFP and AFP+solute aqueous solutions studied by NMR microimaging experiment. (United States)

    Ba, Yong; Mao, Yougang; Galdino, Luiz; Günsen, Zorigoo


    The effects of a type I AFP on the bulk melting of frozen AFP solutions and frozen AFP+solute solutions were studied through an NMR microimaging experiment. The solutes studied include sodium chloride and glucose and the amino acids alanine, threonine, arginine, and aspartic acid. We found that the AFP is able to induce the bulk melting of the frozen AFP solutions at temperatures lower than 0 °C and can also keep the ice melted at higher temperatures in the AFP+solute solutions than those in the corresponding solute solutions. The latter shows that the ice phases were in super-heated states in the frozen AFP+solute solutions. We have tried to understand the first experimental phenomenon via the recent theoretical prediction that type I AFP can induce the local melting of ice upon adsorption to ice surfaces. The latter experimental phenomenon was explained with the hypothesis that the adsorption of AFP to ice surfaces introduces a less hydrophilic water-AFP-ice interfacial region, which repels the ionic/hydrophilic solutes. Thus, this interfacial region formed an intermediate chemical potential layer between the water phase and the ice phase, which prevented the transfer of water from the ice phase to the water phase. We have also attempted to understand the significance of the observed melting phenomena to the survival of organisms that express AFPs over cold winters.

  12. 抗冷冻蛋白基因(afp)转化大豆的研究%Transformation of Soybean with Antifreeze Protein Gene

    Institute of Scientific and Technical Information of China (English)

    陈颖珊; 陈晟; 赵印华; 郭丽琼; 林俊芳



  13. 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)




  14. 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) ...

  15. 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) ...

  16. 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) ...

  17. 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) ...

  18. 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)




  19. 抗冻胀刚性渠道衬砌层断面设计的探讨%Study of the Anti-freezing Rigid Channel Liner Layer Section Design

    Institute of Scientific and Technical Information of China (English)

    张宏; 张伯平; 牟过斌



  20. 抗冻基因CBF2表达载体构建及转化紫花苜蓿的研究%Construction of antifreeze gene CBF2 expression vector and transformation into alfalfa callus

    Institute of Scientific and Technical Information of China (English)

    刘晓静; 郝凤; 张德罡; 毛娟; 于铁峰


    Arabidopsis thaliana genomic DNA was selected as a template to amplify the target gene by PCR and connect it to the PGEM-T Easy Vector for construction of the T-CBF2. The target fragment and linear plasmids were obtained from the cloning vector T-CBF2 and from the plant expression vector PBI121 with dual digestion using BamH I and Sac I, respectively. The plant expression vector P-T-CBF2 was built through directional connections using T4 DNA ligase. PCR identification proved that the recombinant had been transferred into Agrobacterium tumefaciens and it was then introduced into Medicago sativa cv. Hetian through Agrobacterium-mediated transformation. Transfer of the target gene to alfalfa callus was successful.%本研究以拟南芥基因组DNA为模板,用PCR方法扩增目的基因,连接到PGEM-T Easy Vector载体上构建成克隆载体T-CBF2.用BamHI和Sacl分别对克隆载体T-CBF2和植物表达载体PBIl21进行双酶切,获得目的片段和线性质粒.在T4 DNA连接酶的作用下进行定向连接,构建成植物表达载体P-T-CBF2.采用直接转化法将重组子导入根癌农杆菌EHA105.经PCR鉴定,重组质粒已成功导入根癌农杆菌中.通过农杆菌介导法转化和田苜蓿,现在已经得到转基因的苜蓿愈伤组织.

  1. A safe and effective propylene glycol based capture liquid for fruit fly (Diptera: Tephritidae) traps baited with synthetic lures (United States)

    Antifreeze is often used as the capture liquid in insect traps for its preservation and evaporation attributes. In tests reported herein, fruit fly traps using non-toxic household propylene glycol based antifreeze captured significantly more Anastrepha ludens than did traps with the automotive anti...

  2. 49 CFR 173.62 - Specific packaging requirements for explosives. (United States)


    ... filled with water saturated material such as an anti-freeze solution or wetted cushioning 2. Outer packagings must be filled with water saturated material such as an anti-freeze solution or wetted cushioning... Bagspaper, Kraft paper, multiwall, water resistant plastics textile textile, rubberized plastics...

  3. Potentially Dangerous Items for Your Pet (United States)

    ... toxic, even deadly, to birds, rabbits, horses, and ruminants such as cattle, goats, and sheep) Caffeine (found ... Antifreeze Fabric softener sheets Ice melting products Insecticides Liquid potpourri Rat and mouse bait Various household cleaners ( ...

  4. Toxic Amblyopia (Nutritional Amblyopia) (United States)

    ... Contact Lenses Additional Content Medical News Toxic Amblyopia (Nutritional Amblyopia) By James Garrity, MD, Mayo Clinic NOTE: ... or methyl alcohol), antifreeze, or certain drugs. A nutritional deficiency or toxic substance is often the cause ...

  5. Outdoor thermal efficiency evaluation of the Ying solar collector (United States)


    The test procedure used and the test results obtained during an evaluation test program to obtain thermal efficiency performance data are presented. The flat plate collector used water/prestone antifreeze solution as the working fluid.

  6. Antarctic Fishes. (United States)

    Eastman, Joseph T.; DeVries, Arthur L.


    Explains the adaptations to Antarctic waters that Notothenioidei, a group of advanced bony fishes, have exhibited. Discusses the fishes' mechanisms of production of antifreeze properties and their capacities for neutral buoyancy in water. (ML)

  7. 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.

  8. Anti-freezing performance research of dry type shell-tube heat exchanger for air source heat pump water chiller-heater unit%空气源热泵冷(热)水机组用干式壳管换热器防冻性能研究

    Institute of Scientific and Technical Information of China (English)

    张龙爱; 陈忠杰; 王传华


    针对空气源热泵冷(热)水机组运行中可能出现的干式壳管换热器冻裂问题,分析其被冻裂的主要因素,并且对壳管换热器冻裂的关键因素——蒸发压力过低的原因进行分析.基于分析结果,对壳管换热器的设计进行改进,同时对低流量保护点进行试验验证.%Aiming at the frost-cracking problem of the dry type shell-tube heat exchanger for air source heat pump water chiller-heater unit, the main influencing factors are analyzed. The key reason of shell-tube heat exchanger frost-cracking is analyzed that is too low evaporating pressure. The design of shell-tube heat exchanger is improved based on the analysis results, and the limited flow rate for protection of flow switch is verified by the test.

  9. Cloning, Sequencing and Prokaryotic Expression of cDNAs for the Antifreeze Protein Family from the Beetle Tenebrio molitor%Tenebrio molitor抗冻蛋白基因家族cDNA片段的克隆、序列分析及原核表达

    Institute of Scientific and Technical Information of China (English)

    刘忠渊; 王芸; 吕国栋; 王贤磊; 张富春; 马纪


    利用反转录-多聚酶链式反应(RT-PCR)的方法, 克隆黄粉甲虫(Tenebrio molitor)抗冻蛋白基因cDNA片段并进行序列分析和原核表达.同源性分析表明, 获得9条新cDNA片段, 与黄粉甲虫抗冻蛋白基因家族的其他基因序列具有较高的同源性.重组质粒pGEX-4T-1-tmafp-XJ430, 转化E.coli BL21进行原核表达, SDS-PAGE分析结果表明, 抗冻蛋白基因以可溶性融合蛋白表达, 相对分子量为38 kDa.构建真核表达载体pCDNA3-tmafp-XJ430, 免疫小鼠, 获得的抗血清滴度为1:2 000.Western blotting 结果为单一的条带, 证明该抗血清具有针对抗冻蛋白TmAFP-XJ430抗原的专一性.

  10. Bacterial Ice Crystal Controlling Proteins

    Directory of Open Access Journals (Sweden)

    Janet S. H. Lorv


    Full Text Available 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.

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

    Institute of Scientific and Technical Information of China (English)


    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.

  12. 78 FR 31517 - Notification of Proposed Production Activity; Vestas Nacelles America, Inc.; Subzone 123E (Wind... (United States)


    ... and lubricants; assembly pastes; antifreeze/ coolants; fiberglass plates; plastic pipes/tubes/hoses/tapes/sheeting/ trays/cable supports/covers/bags/plugs/bottles/collectors; rubber profiles/strips/sealing lips/hoses/blocks; cardboard containers and frames; gloves; oil sampling kits, of glass;...

  13. Final Environmental Assessment for Installation Development at Little Rock Air Force Base Arkansas (United States)


    of Paleozoic age. A thin drape of younger unconsolidated clays, sands, and gravel (alluvium), is often found in valley floors and is associated with...recovery of antifreeze, used oils and hydraulic fluids, containerizing chromium chips , recycling glass beads and paint chips from the paint stripping

  14. Classical Bahavior of Alumina (Al2O3) Nanofluids in Antifrogen N with Experimental Evidence

    NARCIS (Netherlands)

    Saleemi, M.; Vanapalli, S.; Nikkam, N.; Toprak, M.S.; Muhammed, M.


    A nanofluid is a suspension containing nanoparticles in conventional heat transfer fluids. This paper reports on an investigation of alumina (Al2O3) nanoparticles in Antifrogen N, also called AFN, which is a popular antifreeze coolant consisting primarily of ethylene glycol and other additives to im

  15. First report of suspected ethylene glycol poisoning in 2 dogs in South Africa : clinical communication

    Directory of Open Access Journals (Sweden)

    N. Keller


    Full Text Available Ethylene glycol (anti-freeze toxicity is a serious emergency in both veterinary and human medicine. Ethylene glycol (E/G is the active anti-freeze principle in radiator water additives. It is odourless, colourless and has a sweet taste. As little as 5 mℓ or 20 mℓ is sufficient to kill a cat or a dog, respectively. Ethylene glycol is rapidly absorbed and metabolised in the liver to oxalate, which is deposited as calcium oxalate in the kidneys causing irreversible damage. This report describes 2 dogs that were suspected to have ingested ethylene glycol. The report contains a description of the 3 stages of ethylene glycol toxicity as well as a short discussion of the treatment. Public awareness about the dangers of anti-freeze will help in limiting exposure of pets and humans to this potentially fatal toxin. Veterinarians need to be aware of anti-freeze toxicity as delayed recognition and treatment will lead to the death of the patient.

  16. Complete recovery after massive ethylene glycol ingestion. (United States)

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


    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.

  17. Domain Modeling: NP_001997.5 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_001997.5 chr4 Snow Flea Antifreeze Protein Quasi-racemate p2pnea_ chr4/NP_001997.5/NP_001997.5..._apo_27-110.pdb p3boga_ chr4/NP_001997.5/NP_001997.5_holo_27-110.pdb swppa 33P,34G,36A,60A,61G

  18. Domain Modeling: NP_002211.1 [SAHG[Archive

    Lifescience Database Archive (English)

    Full Text Available NP_002211.1 chr15 Snow Flea Antifreeze Protein Quasi-racemate p2pnea_ chr15/NP_002211.1/NP_002211....1_apo_63-142.pdb p3boga_ chr15/NP_002211.1/NP_002211.1_holo_63-142.pdb swppa 69G,70L,72R,93P,

  19. 75 FR 39520 - Certain New Chemicals; Receipt and Status Information (United States)


    ... customers); monomer in surfactants (to be used by industrial customers in this application); solvent (to be...); solvent (to be used by industrial customers up to 90%); antifreeze in paints and coatings (to be used by...- polymers polyolefins Butanol chloro polymerization titanium complexes P-10-0414 06/08/10 09/05/10 CBI...

  20. Statistical optimization of the growth factors for Chaetoceros neogracile using fractional factorial design and central composite design. (United States)

    Jeong, Sung-Eun; Park, Jae-Kweon; Kim, Jeong-Dong; Chang, In-Jeong; Hong, Seong-Joo; Kang, Sung-Ho; Lee, Choul-Gyun


    Statistical experimental designs; involving (i) a fractional factorial design (FFD) and (ii) a central composite design (CCD) were applied to optimize the culture medium constituents for production of a unique antifreeze protein by the Antartic microalgae Chaetoceros neogracile. The results of the FFD suggested that NaCl, KCl, MgCl2, and Na2SiO3 were significant variables that highly influenced the growth rate and biomass production. The optimum culture medium for the production of an antifreeze protein from C. neogracile was found to be Kalleampersandrsquor;s artificial seawater, pH of 7.0ampersandplusmn;0.5, consisting of 28.566 g/l of NaCl, 3.887 g/l of MgCl2, 1.787 g/l of MgSO4, 1.308 g/l of CaSO4, 0.832 g/l of K2SO4, 0.124 g/l of CaCO3, 0.103 g/l of KBr, 0.0288 g/l of SrSO4, and 0.0282 g/l of H3BO3. The antifreeze activity significantly increased after cells were treated with cold shock (at -5oC) for 14 h. To the best of our knowledge, this is the first report demonstrating an antifreeze-like protein of C. neogracile.

  1. 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)


    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.

  2. Top Value Added Chemicals From Biomass. Volume 1 - Results of Screening for Potential Candidates From Sugars and Synthesis Gas (United States)


    indeterminant Lactones, esters Antifreeze and deicers Fuel oxygenates Green solvents Phthalate polyesters Plasticizers Polyacrylates Polyacrylamides Phenol...UsesIntermediatesBiomass Feedstocks Sugars Glucose Fructose Xylose Arabinose Lactose Sucrose Starch Starch Cellulose Lignin Oil Protein Hemicellulose...molecular families, 2) could be produced from both lignocellulosics and starch , 3) were C1-C6 monomers, 4) were not aromatics derived from lignin, and 5

  3. Oil and gas pipelines with hydrophobic surfaces better equipped to deal with gas hydrate flow assurance issues

    DEFF Research Database (Denmark)

    Perfeldt, Christine Malmos; Sharifi, Hassan; von Solms, Nicolas


    concerns. Here we show the effect of a hydrophobically coated surface on hydrate formation in the presence of an antifreeze protein type I (AFP I) and a biodegradable synthetic polymer (LuvicapBio) in a high pressure crystallizer setup. The hydrophobic surface increased the hydrate induction time...

  4. Inhibition of ice recrystallization and cryoprotective activity of wheat proteins in liver and pancreatic cells. (United States)

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


    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.


    Directory of Open Access Journals (Sweden)

    Semenov Vyacheslav Sergeevich


    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

  6. 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


    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.

  7. Application of solar hot water and geothermal principles to closed-cycle aquaculture (United States)

    Yanzito, R. A.


    The design of an underground silo where warm water food fish could be raised to market size under controlled conditions. The building and solar concept analysis for the closed cycle aquaculture system are described. Energy conservation features of the design include Earth berming and insulation of the production silo and enclosure, a waste water reclaim system and a solar heating system. Much of the water surface area is covered with removable plants to minimize evaporative heat losses. An energy conservation analysis is also reported and the F-Chart computer program is described. The system chosen utilizes single glazed flat plate collectors in a closed loop antifreeze system. Makeup water is introduced during an 8 hour period each day. Solar energy is transferred from the antifreeze solution to the makeup water after it leaves the waste water heat exchanger.

  8. Bioinspiration From Nano to Micro Scales

    CERN Document Server


    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...

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


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


    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 ...

  10. 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)


    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.

  11. Assessment of Superstructure Ice Protection as Applied to Offshore Oil Operations Safety: Ice Protection Technologies, Safety Enhancements, and Development Needs (United States)


    1999). Because it is a liquid, ethylene glycol could be used to deice cranes, lattice structures, and windlasses—although with significant wastage ...distillation or by yeast reduction of hydroxyacetone. It is widely used as a chemical intermediate, a humectant in foods , an emollient in cosmetic...fluids, a non-toxic antifreeze in breweries and dairy establish- ments, an air sterilizer in the vapor form for hospitals and public build- ings, an



    Semenov Vyacheslav Sergeevich; Oreshkin Dmitriy Vladimirovich; Rozovskaya Tamara Alekseevna


    The authors provide their research findings concerning lightweight masonry mortars with hollow glass microspheres and antifreeze admixtures. These mortars are used in the construction of filler structures at negative temperatures. The application of multilayer filler structures causes reduction of their thermal homogeneity factor. Therefore, single-layer filler structures have the strongest potential. There is a need to employ lightweight masonry mortars to ensure the thermal homogeneity of s...

  13. Great Lakes Demonstration 2 (United States)


    without state environmental permission. Alternatively, the antifreeze was drained into a bucket and temporarily stored onboard the tugboat. The...Under Ice Retrieval If capable, the ROV or diver would be utilized to dive under the ice with an appropriate suction hose to find and recover oil...types of skimmers. If the oil is thick enough, it can be removed using direct suction . G.3.5.2 Broken Ice Conditions – Slotting: Objective of this



    V. Cherepnin


    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 mealwo...

  15. 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


    <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

  16. Thermophysical Properties of Aqueous Solutions Used as Secondary Working Fluids


    Melinder, Åke


    Secondary working fluids (secondary refrigerants, heat transfer fluids, antifreezes, brines) have long been used in various indirect re-frigeration and heat pump systems. Aqueous solutions (water solu-tions) have long been used as single phase (liquid only) secondary working fluids for cooling in supermarkets, ice rinks, heat recovery systems, heat pumps and other applications. However, aqueous solutions are increasingly used also for freezers in supermarkets and other applications in low tem...

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


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


    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...

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

    Institute of Scientific and Technical Information of China (English)


    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...

  19. Solute effects on ice recrystallization: an assessment technique. (United States)

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


    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.

  20. 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


    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.

  1. Determination of the Amount of Concrete Anti ̄freezing Agent with Comprehensive Thermal Storage Method%综合蓄热法混凝土防冻剂掺量的确定

    Institute of Scientific and Technical Information of China (English)

    刘方达; 王维才


    The unreasonable aspects for ascertaining the amount of concrete anti-freezing agent used in the present comprehensive thermal storage method is pointed out. A new method for determining the amount of anti-freezing agent used in the negative temperature concrete was proposed through tests, based on the thermal calculating formula, maturity formula and the freezing points of different kinds of concrete with different amount of anti-freezing agent. The new method was proved to be convenient and feasible by tests.%指出当前综合蓄热法施工中确定混凝土防冻剂掺量的不尽合理之处,经试验研究提出了以混凝土热工计算公式和成熟度公式为基础,结合不同掺量防冻剂混凝土的不同冰点,提出负温混凝土防冻剂掺量的新方法。并通过试验进行了验证,得出该方法方便可行。

  2. Boreal pollen contain ice-nucleating as well as ice-binding ‘antifreeze’ polysaccharides (United States)

    Dreischmeier, Katharina; Budke, Carsten; Wiehemeier, Lars; Kottke, Tilman; Koop, Thomas


    Ice nucleation and growth is an important and widespread environmental process. Accordingly, nature has developed means to either promote or inhibit ice crystal formation, for example ice-nucleating proteins in bacteria or ice-binding antifreeze proteins in polar fish. Recently, it was found that birch pollen release ice-nucleating macromolecules when suspended in water. Here we show that birch pollen washing water exhibits also ice-binding properties such as ice shaping and ice recrystallization inhibition, similar to antifreeze proteins. We present spectroscopic evidence that both the ice-nucleating as well as the ice-binding molecules are polysaccharides bearing carboxylate groups. The spectra suggest that both polysaccharides consist of very similar chemical moieties, but centrifugal filtration indicates differences in molecular size: ice nucleation occurs only in the supernatant of a 100 kDa filter, while ice shaping is strongly enhanced in the filtrate. This finding may suggest that the larger ice-nucleating polysaccharides consist of clusters of the smaller ice-binding polysaccharides, or that the latter are fragments of the ice-nucleating polysaccharides. Finally, similar polysaccharides released from pine and alder pollen also display both ice-nucleating as well as ice-binding ability, suggesting a common mechanism of interaction with ice among several boreal pollen with implications for atmospheric processes and antifreeze protection. PMID:28157236

  3. Boreal pollen contain ice-nucleating as well as ice-binding ‘antifreeze’ polysaccharides (United States)

    Dreischmeier, Katharina; Budke, Carsten; Wiehemeier, Lars; Kottke, Tilman; Koop, Thomas


    Ice nucleation and growth is an important and widespread environmental process. Accordingly, nature has developed means to either promote or inhibit ice crystal formation, for example ice-nucleating proteins in bacteria or ice-binding antifreeze proteins in polar fish. Recently, it was found that birch pollen release ice-nucleating macromolecules when suspended in water. Here we show that birch pollen washing water exhibits also ice-binding properties such as ice shaping and ice recrystallization inhibition, similar to antifreeze proteins. We present spectroscopic evidence that both the ice-nucleating as well as the ice-binding molecules are polysaccharides bearing carboxylate groups. The spectra suggest that both polysaccharides consist of very similar chemical moieties, but centrifugal filtration indicates differences in molecular size: ice nucleation occurs only in the supernatant of a 100 kDa filter, while ice shaping is strongly enhanced in the filtrate. This finding may suggest that the larger ice-nucleating polysaccharides consist of clusters of the smaller ice-binding polysaccharides, or that the latter are fragments of the ice-nucleating polysaccharides. Finally, similar polysaccharides released from pine and alder pollen also display both ice-nucleating as well as ice-binding ability, suggesting a common mechanism of interaction with ice among several boreal pollen with implications for atmospheric processes and antifreeze protection.

  4. Ice-binding proteins that accumulate on different ice crystal planes produce distinct thermal hysteresis dynamics. (United States)

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


    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.

  5. Characterization and multi-generational stability of the growth hormone transgene (EO-1alpha) responsible for enhanced growth rates in Atlantic Salmon. (United States)

    Yaskowiak, Edward S; Shears, Margaret A; Agarwal-Mawal, Alka; Fletcher, Garth L


    Transgenic technologies provide a promising means by which desirable traits can be introduced into cultured fish species within a single generation thus accelerating the production of genetically superior broodstock for aquaculture. However, before such fish are allowed to be marketed as food they must receive government regulatory approval. Two pivotal regulatory requirements are: (1) complete characterization of the genomically integrated transgene and, (2) demonstration that the transgene remains stable over multiple generations. We have generated a stable line of growth hormone (GH) transgenic Atlantic salmon (Salmo salar) using an "all fish" gene construct (opAFP-GHc2) containing a growth hormone cDNA from chinook salmon whose expression is regulated by the 5' promoter and 3' termination regions derived from an ocean pout antifreeze protein (AFP) gene. In this study we show that a reorganized form of the opAFP-GHc2 construct (termed EO-1alpha) integrated as a single functional copy into a 35 bp repeat region of the genomic DNA. PCR based mapping revealed that the linear sequence of the EO-1alpha integrant was organized as follows: base pairs 1580-2193 of the ocean pout promoter region followed by the intact chinook salmon GH cDNA, the complete ocean pout antifreeze 3' region, and the first 1678 bp of the ocean pout antifreeze 5' region. Sequence analysis of the EO-1alpha integrant and genomic flanking regions in F2 and F4 generation salmon revealed that they were identical. In addition, apart from the disruption at the integration sites, the consensus sequences of the integrant in these two generations of salmon were identical to the sequence of the opAFP-GHc2 construct. These results indicate that the EO-1alpha transgene codes for the chinook salmon GH, and that the transgene and the integration site have remained stable over multiple generations.

  6. Molecular cloning and functional analyses of low-temperature induced genes from Ammopiptanthus mongolicus

    Institute of Scientific and Technical Information of China (English)


    Studies on the cold-responsive genes and cold signaling of woody species drop far behind in comparison to herbaceous plants.Due to similar lignified structure,perennial characteristic,and enhanced tolerance,it seems much easier to find strongly antifreeze genes and obtain effective results in transgenic woody plants.In this study,Ammopiptanthus mongolicus,an evergreen,broadleaf and cold-resist leguminous shrub growing in the desert of Inner Mongolia,was used as a material for low-temperature induced gene is...

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

    Energy Technology Data Exchange (ETDEWEB)



    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)

  8. Data from thermal testing of the Open Source Cryostage

    Directory of Open Access Journals (Sweden)

    Johannes Lørup Buch


    Full Text Available 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.

  9. TA-60-1 Heavy Equipment Shop Areas SWPPP Rev 2 Jan 2017-Final

    Energy Technology Data Exchange (ETDEWEB)

    Burgin, Jillian Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    The primary activities and equipment areas at the facility that are potential stormwater pollution sources include; The storage of vehicles and heavy equipment awaiting repair; or repaired vehicles waiting to be picked up; The storage and handling of oils, anti-freeze, solvents, degreasers, batteries and other chemicals for the maintenance of vehicles and heavy equipment; and Equipment cleaning operations including exterior vehicle wash-down. Steam cleaning is only done on the steam cleaning pad area located at the north east end of Building 60-0001.

  10. Unusual clinical presentation of ethylene glycol poisoning: unilateral facial nerve paralysis. (United States)

    Eroglu, Eray; Kocyigit, Ismail; Bahcebasi, Sami; Unal, Aydin; Sipahioglu, Murat Hayri; Kocyigit, Merva; Tokgoz, Bulent; Oymak, Oktay


    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.

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

    Directory of Open Access Journals (Sweden)

    F. M. Engels


    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.

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

    Directory of Open Access Journals (Sweden)

    Eray Eroglu


    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.

  13. A Management Information System for Bare Base Civil Engineering Commanders (United States)


    16" RA 1 1 Yes 31 ANTIFREEZE MIX 300AL DR IA 3 3 Yes 51 BLOCK ICE MACHINE IA 1 1 Yea 66 CABLE ELECTRIC RUBBER CL 1 1 Ye- 124 UNTO-INSICTICIDE DIAZINON ... liver cells caused by a virus entering the body through the digestive system or the circulatory system (e.g., blood transfusions or contaminated...swollen, tender liver . DO --treat with bed rest and a high protein diet. -- sat only carefully washed and well-prepared food. --emphasize personal

  14. Data from thermal testing of the Open Source Cryostage

    DEFF Research Database (Denmark)

    Buch, Johannes Lørup; Ramløv, Hans


    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....

  15. Growth enhancement in transgenic Atlantic salmon by the use of an "all fish" chimeric growth hormone gene construct. (United States)

    Du, S J; Gong, Z Y; Fletcher, G L; Shears, M A; King, M J; Idler, D R; Hew, C L


    We have developed an "all fish" growth hormone (GH) chimeric gene construct by using an antifreeze protein gene (AFP) promoter from ocean pout linked to a chinook salmon GH cDNA clone. After microinjection into fertilized, nonactivated Atlantic salmon eggs via the micropyle, transgenic Atlantic salmon were generated. The presence of the transgene was detected by polymerase chain reaction (PCR) using specific oligonucleotide primers. A number of these transgenic fish showed dramatic increases in their growth rate. At one year old, the average increase of the transgenic fish was 2 to 6 fold and the largest transgenic fish was 13 times that of the average non-transgenic control.

  16. AcEST: BP912564 [AcEST

    Lifescience Database Archive (English)

    Full Text Available tr|Q9PKM7|Q9PKM7_CHLMU Adherence factor OS=Chlamydia muridarum G... 33 9.2 >tr|A7F6B5|A7F6B5_SCLS1|Q9PKM7|Q9PKM7_CHLMU Adherence factor OS=Chlamydia muridarum GN=TC_0438 PE=4 SV...3 DHC+ C N + C FV S G+CK + Y Q+C NPP Sbjct: 2216 DHCVACLNPQTCTQCQPLFVLQSD--------GTCKVQPGYYCQQDCQNNPP 2259 >...34 4.1 tr|Q22BL5|Q22BL5_TETTH Insect antifreeze protein OS=Tetrahymena ... 33 7.1

  17. Numerical analysis of heat exchange processes for the ground source heat pump system (United States)

    Saito, H.; Muto, H.; Moritani, S.; Kohgo, Y.; Hamamoto, S.; Takemura, T.; Ohnishi, J.; Komatsu, T.


    Ground source heat pump systems (GSHP) use ground or groundwater as a heat source. They can achieve much higher coefficient of performance (COP) than conventional air source heat pump systems because the temperature of the ground is much more stable than that of the air. Heat energy in the ground is then viewed as one of the renewable energy sources. GSHP has been receiving great interests among countries in North America and Western Europe, as well as some developed countries in Asia because it can potentially reduce energy consumption and greenhouse gas emission. While GSHP can inject heat from the buildings to the ground for cooling during the summer, it can pump heat stored in the ground for heating during the winter. As some physical, chemical, and biological properties of the ground and groundwater are temperature dependent, running GSHP can eventually affect groundwater quality. The main objective of this project was to develop a model that allows predicting not only ground and groundwater temperatures but also changes in physical, chemical, and biological properties of ground and groundwater with GSHP under operations. This particular study aims at simulating heat exchange and transfer processes in the ground for a vertical-loop closed GSHP system. In the closed GSHP system, an anti-freezing solution is circulated inside the closed-loop tube, called U-tube, that is buried in the ground. Heat is then transferred to the anti-freezing solution in the U-tube by a heat exchanger. In this study we used HYDRUS to predict temperature of the anti-freezing solution, as well as that of the ground. HYDRUS allows one to simulate variably-saturated water flow and solute and heat transport in porous media numerically in two- and three-dimensional domains with great flexibility in defining boundary conditions. At first changes in anti-freezing solution temperatures measured were predicted in response to Thermal Response Test (TRT) conducted at our study site. Then, heat

  18. Spectrophotometric determination of Sudan Blue II in environmental samples after dispersive liquid-liquid microextraction

    Directory of Open Access Journals (Sweden)

    Yunus Emre Unsal


    Full Text Available A dispersive liquid-liquid microextraction procedure coupled to spectrophotometry is described for the determination of the trace levels of Sudan Blue II. Analytical parameters, such as pH, volume of extraction solvent (carbon tetrachloride, volume of dispersant (ethanol, volume of sample, and extraction time, were optimized. Matrix effects were also investigated. Preconcentration factor was found to be 200. Detection limit and relative standard deviation (RSD were 0.55 µg L-1 and 3.9%, respectively. The procedure was successfully used for the determination of trace levels of Sudan Blue II in food, ink, antifreeze, and industrial waste-water samples.

  19. Environmental Impact Statement for Proposed Closure of Los Angeles Air Force Base, California and Relocation of Space Systems Division (United States)


    cu ft Acetylene No. 4 6,000 cu ft Anyhydrous Ammonia No. 5 25 gal Ammonium Hydroxide No. 6 100 gal Ethylene Glycol Antifreeze No. 7 200 gal Asphalt ...Adhesive No. 8 300 gal Asphalt Emulsion No. 9 1,000 gal Assorted Paints No. 10 200 cans Spray Paint - 14 oz each No. 11 100 cyls Propane - 14 oz...Compressor Lube Oil No. 16 100 gal ENTEC 327 - (loprophyl, Ethyl Aichols) No. 17 125 gal ENTEC 349 - (Dodecylguanideine HC ! ,lsoOHMethyl (bis) Isocyanate

  20. 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


    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.

  1. Mechanical interactions between ice crystals and red blood cells during directional solidification. (United States)

    Ishiguro, H; Rubinsky, B


    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.

  2. Taxonomic characterization, adaptation strategies and biotechnological potential of cryophilic yeasts from ice cores of Midre Lovénbreen glacier, Svalbard, Arctic. (United States)

    Singh, Purnima; Tsuji, Masaharu; Singh, Shiv Mohan; Roy, Utpal; Hoshino, Tamotsu


    Ten strains of cryophilic yeast were studied from glacier ice cores of Svalbard, Arctic. The ice melt samples contained about 3×10(3) - 1×10(4) colony forming unit (CFUs) per ml. Sequence analysis of the isolates, using D1/D2 domain identified five species of yeasts: Cryptococcus adeliensis (MLB-18 JX192655), Cryptococcus albidosimilis (MLB-19 JX192656), Cryptococcus saitoi (MLB-22 JX192659), Rhodosporidium lusitaniae (MLB-20 JX192657), and Rhodotorula mucilaginosa (MLB-27 JX192664). Effect of temperature on growth of these isolates was studied. The strains are able to grow at temperatures ranging between 1 and 20°C. Screening of the cultures for amylase, cellulase, protease, lipase, urease and catalase activity were carried out indicating varying amounts of enzyme production at different temperatures. Characterization of lipase in strain Cryptococcus sp. MLB-24 was performed. Fatty acid methyl ester (FAME) analysis of the cultures grown at four different temperatures (1, 4, 15, and 20°C) was also done. Decrease in temperature was reported to cause increase in concentration of unsaturated fatty acids. High amount of oleic acid accumulated with increase in temperature. These fatty acids possibly help the strains to survive in glacial ice core cold environment. The extracellular and intracellular filtrate of the cultures showed negative antifreeze protein (AFP) activity. The observations indicate that probably the isolates in the present undertaking adapt to low temperatures, by enzyme and PUFA secretion rather than by antifreeze protein secretion.

  3. 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


    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.

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

    Institute of Scientific and Technical Information of China (English)

    Sarmistha Saha; Ramtej J Verma


    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.

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

    Mitchell, Daniel E; Gibson, Matthew I


    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.


    Directory of Open Access Journals (Sweden)

    V. Cherepnin


    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

  7. 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


    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

  8. Cloning of fish enzymes and other fish protein genes. (United States)

    Macouzet, M; Simpson, B K; Lee, B H


    Fish metabolism needs special enzymes that have maximum activity at very different conditions than their mammalian counterparts. Due to the differences in activity, these enzymes, especially cold-adapted proteases, could be used advantageously for the production of some foods. In addition to the enzymes, this review describes some other unique fish polypeptides such as antifreeze proteins, fluorescent proteins, antitumor peptides, antibiotics, and hormones, that have already been cloned and used in food processing, genetic engineering, medicine, and aquaculture. Recombinant DNA technology, which allows these biological molecules to be cloned and overexpressed in microorganisms is also described, highlighting innovative applications. The expected impact of cloning fish proteins in different fields of technology is discussed.

  9. Production technology of frozen fish-surimi and surimi products%冷冻鱼糜及鱼糜制品生产工艺技术

    Institute of Scientific and Technical Information of China (English)



    介绍了冷冻鱼糜生产工艺流程,重点阐述冷冻鱼糜的采肉、漂洗、脱水、添加冷冻变性防止剂等工艺要点。同时,介绍了以冷冻鱼糜为原料生产鱼糜制品的工艺流程,着重阐述了擂溃和凝胶化等工艺要点。%Production process of frozen fish-surimi was introduced in this article,the technology points such as selecting meat,rinsing,dehydration,adding antifreeze agent were described in detail.Meanwhile,the technological process of surimi products produced by frozen fish-surimi was introduced,and blending and gelating process was emphatically described.

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

    Directory of Open Access Journals (Sweden)

    Pavel Neuberger


    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.

  11. On the edge of habitability and the extremes of liquidity (United States)

    Hansen-Goos, Hendrik; Thomson, Erik S.; Wettlaufer, J. S.


    The physical and biological mechanisms that extend the equilibrium domain of liquid water into the ice region of the bulk phase diagram are examined in view of their importance for the enhancement of planetary habitability. The physical phenomena studied are the premelting of ice, which allows for films of liquid water at temperatures well below freezing, and the wetting of hygroscopic salts with the persistence of briny films even for thermodynamic conditions remote from those of bulk liquid water. Organisms are known to produce a variety of frost-suppressing substances, one of which, the anti-freeze protein, is described here. In this article, we provide a synthesis of theoretical and experimental studies whilst extending ideas into new territory as we address the question of habitability.

  12. First-time installation of a floor heating mat in a church

    Energy Technology Data Exchange (ETDEWEB)

    Hauck, E.

    Floor heating mats operate at a very low flow temperature of about 30/sup 0/C. This results in a considerable reduction of transfer losses and allows for the utilization of both renewable energy sources obtaining at a low level and waste heat. Floor heating mats need no costly and high-piling floor structure and are simply spread on to the foot fall-sound insulation. The system has been used successfully for heating a church in Belgium. The floor of the church was covered with Thermoflex heating elements consisting of PVC-coated Trevira fabric equipped with spacing fixators. The covered surface of 187 sqm was subdivided into 5 separately switchable circuits. A 30 kW low-temperature boiler was employed. The heating water with added antifreeze circulates throughout the total covered surface. Heating element costs amounted to DM 23,000, i.e. about DM 120 per sqm.

  13. 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)



    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.

  14. Solar hot water system installed at Day's Inn Motel, Savannah, Georgia (United States)


    The Solar System was designed to provide 50 percent of the total Domestic Hot Water (DHW) demand. Liquid Flat Plate Collectors (900 square feet) are used for the collector subsystem. The collector subsystem is closed loop, using 50 percent Ethylene Glycol solution antifreeze for freeze protection. The 1,000 gallon fiber glass storage tank contains two heat exchangers. One of the heat exchangers heats the storage tank with the collector solar energy. The other heat exchanger preheats the cold supply water as it passes through on the way to the Domestic Hot Water (DHW) tank heaters. Electrical energy supplements the solar energy for the DHW. The Collector Mounting System utilizes guy wires to structurally tie the collector array to the building.

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


    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.

  16. Pathogen-mediated manipulation of arthropod microbiota to promote infection (United States)

    Abraham, Nabil M.; Liu, Lei; Jutras, Brandon Lyon; Yadav, Akhilesh K.; Narasimhan, Sukanya; Gopalakrishnan, Vissagan; Ansari, Juliana M.; Jefferson, Kimberly K.; Cava, Felipe; Jacobs-Wagner, Christine; Fikrig, Erol


    Arthropods transmit diverse infectious agents; however, the ways microbes influence their vector to enhance colonization are poorly understood. Ixodes scapularis ticks harbor numerous human pathogens, including Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis. We now demonstrate that A. phagocytophilum modifies the I. scapularis microbiota to more efficiently infect the tick. A. phagocytophilum induces ticks to express Ixodes scapularis antifreeze glycoprotein (iafgp), which encodes a protein with several properties, including the ability to alter bacterial biofilm formation. IAFGP thereby perturbs the tick gut microbiota, which influences the integrity of the peritrophic matrix and gut barrier—critical obstacles for Anaplasma colonization. Mechanistically, IAFGP binds the terminal d-alanine residue of the pentapeptide chain of bacterial peptidoglycan, resulting in altered permeability and the capacity of bacteria to form biofilms. These data elucidate the molecular mechanisms by which a human pathogen appropriates an arthropod antibacterial protein to alter the gut microbiota and more effectively colonize the vector. PMID:28096373

  17. Solar heating and hot water system installed at Arlington Raquetball Club, Arlington, Virginia (United States)


    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. Water impacting on superhydrophobic macrotextures. (United States)

    Gauthier, Anaïs; Symon, Sean; Clanet, Christophe; Quéré, David


    It has been recently shown that the presence of macrotextures on superhydrophobic materials can markedly modify the dynamics of water impacting them, and in particular significantly reduce the contact time of bouncing drops, compared with what is observed on a flat surface. This finding constitutes a significant step in the maximization of water repellency, since it enables to minimize even further the contact between solid and liquid. It also opens a new axis of research on the design of super-structures to induce specific functions such as anti-freezing, liquid fragmentation and/or recomposition, guiding, trapping and so on. Here we show that the contact time of drops bouncing on a repellent macrotexture takes discrete values when varying the impact speed. This allows us to propose a quantitative analysis of the reduction of contact time and thus to understand how and why macrotextures can control the dynamical properties of bouncing drops.


    Directory of Open Access Journals (Sweden)

    VLASOV Vladimir Alexeevich


    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.

  20. The overwintering physiology of the emerald ash borer, Agrilus planipennis fairmaire (coleoptera: buprestidae). (United States)

    Crosthwaite, Jill C; Sobek, Stephanie; Lyons, D Barry; Bernards, Mark A; Sinclair, Brent J


    Ability to survive cold is an important factor in determining northern range limits of insects. The emerald ash borer (Agrilus planipennis) is an invasive beetle introduced from Asia that is causing extensive damage to ash trees in North America, but little is known about its cold tolerance. Herein, the cold tolerance strategy and mechanisms involved in the cold tolerance of the emerald ash borer were investigated, and seasonal changes in these mechanisms monitored. The majority of emerald ash borers survive winter as freeze-intolerant prepupae. In winter, A. planipennis prepupae have low supercooling points (approximately -30°C), which they achieve by accumulating high concentrations of glycerol (approximately 4M) in their body fluids and by the synthesis of antifreeze agents. Cuticular waxes reduce inoculation from external ice. This is the first comprehensive study of seasonal changes in cold tolerance in a buprestid beetle.

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

    CERN Document Server

    Aringazin, A K


    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...

  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


    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. Detecting thermal hysteresis activity of the total protein in insects with differential scanning calorimetry%应用差示扫描量热法检测昆虫总蛋白的热滞活性

    Institute of Scientific and Technical Information of China (English)

    崔宁宁; 宋希明; 邹元平; 郝树广; 许永玉; 王宪辉


    产生抗冻蛋白是寒带昆虫抵御低温的重要机制之一,但检测其活性仍存在一些困难,尤其对于个体较小的昆虫样品.为了探索差示扫描量热法是否适于检测昆虫总蛋白的热滞活性,本研究利用差示扫描量热法对黄粉虫Tenebrio molitor幼虫的总蛋白和血淋巴分别进行了热滞活性检测.结果表明:黄粉虫总蛋白的热滞活性(0.49~0.98℃)要低于血淋巴(2.54 ~4.34C).通过这种方法,进一步检测了3种在内蒙古大兴安岭林区采集到的越冬昆虫:稠李巢蛾Yponomeuta evonymallus幼虫、舞毒蛾Lymantria dispar卵和落叶松八齿小蠹Ips subelongatus成虫.结果发现,它们都存在热滞活性,其中稠李巢蛾的热滞活性为0.34 ~0.43℃,舞毒蛾的热滞活性为0.35~0.42℃,落叶松八齿小蠹的热滞活性为0.37 ~0.40℃,说明这3种昆虫能以产生抗冻蛋白的方式作为越冬策略之一.本研究表明通过差示扫描量热法检测昆虫总蛋白是否存在热滞活性来判断抗冻蛋白的存在是可行的.%Producing antifreeze proteins is one of the most important mechanisms underlying insect cold tolerance. However, detecting the activity of antifreeze proteins still has some difficulties, especially when only a few of insect samples are available from fields. In order to explore if differential scanning calorimetry (DSC) can be used to detect thermal hysteresis activity ( THA) of the total protein in insects, the THA of the total protein and hemolymph from Tenebrio molitor larvae was detected by DSC. The results showed that the THA of the total protein (0. 49 -0. 98t ) is lower than that of hemolymph (2. 54 -4. 341) in T. molitor. In addition, we collected three overwintering insect species (Lymantria dispar larvae, Yponomeuta evonymallus eggs and Ips subelongatus adults) in the Daxing' anling Forest Region in Inner Mongolia, and then prepared their total protein. Using DSC, the THA of the total protein from the three


    Institute of Scientific and Technical Information of China (English)

    刘丽明; 王晓波; 王萍; 张焕仁


    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. Expression of a novel piscine growth hormone gene results in growth enhancement in transgenic tilapia (Oreochromis niloticus). (United States)

    Rahman, M A; Mak, R; Ayad, H; Smith, A; Maclean, N


    Several lines of transgenic G1 and G2 tilapia fish (Oreochromis niloticus) have been produced following egg injection with gene constructs carrying growth hormone coding sequences of fish origin. Using a construct in which an ocean pout antifreeze promoter drives a chinook salmon growth hormone gene, dramatic growth enhancement has been demonstrated, in which the mean weight of the 7 month old G2 transgenic fish is more than three fold that of their non transgenic siblings. Somewhat surprisingly G1 fish transgenic for a construct consisting of a sockeye salmon metallothionein promoter spliced to a sockeye salmon growth hormone gene exhibited no growth enhancement, although salmon transgenic for this construct do show greatly enhanced growth. The growth enhanced transgenic lines were also strongly positive in a radio-immuno assay for the specific hormone in their serum, whereas the non growth enhanced lines were negative. Attempts to induce expression from the metallothionein promoter by exposing fish to increased levels of zinc were also unsuccessful. Homozygous transgenic fish have been produced from the ocean pout antifreeze/chinook salmon GH construct and preliminary trials suggest that their growth performance is similar to that of the hemizygous transgenics. No abnormalities were apparent in the growth enhanced fish, although minor changes to skull shape and reduced fertility were noted in some fish. There is also preliminary evidence for improved food conversion ratios when growth enhanced transgenic tilapia are compared to their non-transgenic siblings. The long term objective of this study is to produce lines of tilapia which are both growth enhanced and sterile, so offering improved strains of this important food fish for aquaculture.

  6. 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


    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).

  7. Influence of Track Ramp on Adhesion Characteristic of Wheel/Rail under Third Medium Conditions%第三介质作用下坡道对轮轨黏着特性影响

    Institute of Scientific and Technical Information of China (English)

    黄万亮; 何成刚; 师陆冰; 王文健; 刘启跃


    A testing fixture is designed to simulate different track gradient contacts of wheel/rail,and the effects of track ramp on adhesion behaviors under third medium conditions were explored in detail using JD-lwheel/rail simulation apparatus.The results indicate that,compared with the level track,the adhesion coefficient of wheel/rail of ramp track had a significant fall under dry,water or antifreeze medium conditions.Furthermore,the adhesion coefficient showed a downward trend with the increasing track gradient and the adhesion coefficient of decent track loss more than that of ascent track.Compared with the water,lower adhesion phenomenon appeared easily due to the spilled antifreeze fluid.Moreover,with the increasing speed and load,the adhesion coefficient of wheel/rail rollers presented a slightly downward trend.%利用JD-1轮轨模拟试验机,通过设计坡道试验夹具实现了不同坡道接触条件的轮轨模拟试验,研究了第三介质条件下坡度对轮轨界面黏着特性的影响规律.结果表明:在干态、水介质和防冻液介质条件下,上下坡道工况的轮轨黏着系数均低于平直轨道工况;随坡道坡度的增加,黏着系数呈下降趋势且下坡道的黏着系数下降更为明显;与水介质相比较,轮轨界面存在防冻液时更容易引起低黏着现象;上坡道工况下,随速度和轴重的增加轮轨界面黏着系数呈略微下降的趋势.

  8. 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


    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.

  9. 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


    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 ℃.

  10. 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.


    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

  11. Geophysics and geochemistry intertwined: Modeling the internal evolution of Ceres, Pluto, and Charon (United States)

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


    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

  12. Surface Morphology of Ice and Ice with AFGP studied with Atomic Force Microscopy (United States)

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


    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.

  13. Atomic force microscope chamber for in situ studies of ice (United States)

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


    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.

  14. Cold tolerance of the Antarctic nematodes Plectus murrayi and Scottnema lindsayae. (United States)

    Wharton, David A; Raymond, Mélianie R


    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.

  15. Corrosion problems with aqueous coolants, final report

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  16. Perplexing cooperative folding and stability of a low-sequence complexity, polyproline 2 protein lacking a hydrophobic core. (United States)

    Gates, Zachary P; Baxa, Michael C; Yu, Wookyung; Riback, Joshua A; Li, Hui; Roux, Benoît; Kent, Stephen B H; Sosnick, Tobin R


    The burial of hydrophobic side chains in a protein core generally is thought to be the major ingredient for stable, cooperative folding. Here, we show that, for the snow flea antifreeze protein (sfAFP), stability and cooperativity can occur without a hydrophobic core, and without α-helices or β-sheets. sfAFP has low sequence complexity with 46% glycine and an interior filled only with backbone H-bonds between six polyproline 2 (PP2) helices. However, the protein folds in a kinetically two-state manner and is moderately stable at room temperature. We believe that a major part of the stability arises from the unusual match between residue-level PP2 dihedral angle bias in the unfolded state and PP2 helical structure in the native state. Additional stabilizing factors that compensate for the dearth of hydrophobic burial include shorter and stronger H-bonds, and increased entropy in the folded state. These results extend our understanding of the origins of cooperativity and stability in protein folding, including the balance between solvent and polypeptide chain entropies.

  17. 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


      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.

  18. Technology progress of EO production%环氧乙烷生产技术进展

    Institute of Scientific and Technical Information of China (English)

    王海蔷; 刘昱


    EO is able to derive many kinds of fine chemicals.such as:glycol,non-ionic surfactant,etha nol amino,glycol ether amine and so on,and can be extended to produce synthetic detergent,emulsifi-er,antifreeze agent, plasticizer, lubricants, pesticides, fumigants, Its application field is extremely extensive. This paper introduced EO production technology development, put forward the development proposal of EO in our country,such as developing large-scale reactor,expanding the development and application of its down-stream products.%环氧乙烷能够衍生出乙二醇、非离子表面活性剂、乙醇胺、乙二醇醚等多种精细化工产品,进而可以延伸生产合成洗涤剂、乳化剂、抗冻剂、增塑剂、润滑剂、杀虫剂、熏蒸剂等五千余种产品,应用领域极其广泛.作者对国内外环氧乙烷生产技术发展现状进行了分析,并提出了我国环氧乙烷的发展建议,即开发大型反应器,加大其下游产品的开发与应用等.

  19. The galactose-recognizing system of rat peritoneal macrophages; identification and characterization of the receptor molecule. (United States)

    Kelm, S; Schauer, R


    Resident rat peritoneal macrophages express a galactose-recognizing system, which mediates binding and uptake of cells and glycoproteins exposing terminal galactose residues. Here we describe the identification, isolation, and characterization of the corresponding receptor molecule. Using photoaffinity labelling of adherent peritoneal macrophages with the 4-azido-6-125I-salicylic acid derivative of anti-freeze glycoprotein 8 followed by SDS-PAGE and autoradiography, we identified the receptor of these cells as a protein with an apparent molecular mass of 42 kDa. Furthermore, cell surface receptors were radioiodinated by an affinity-supported labelling technique using the conjugate of asialoorosomucoid and lactoperoxidase, followed by extraction and isolation by affinity chromatography. Finally, the native receptor was isolated and analysed. To estimate its binding activity in solutions, a suitable binding assay was developed, using the precipitation of receptor-ligand complex with polyethylene glycol to separate bound from unbound 125I-asialoorosomucoid, which was used as ligand. It is shown that the isolated receptor binds to galactose-exposing particles and distinguishes between sialidase-treated and -untreated erythrocytes, similar to peritoneal macrophages. The binding characteristics of the membrane-bound and the solubilized receptor are described in the following paper of Lee et al.

  20. Structure and Combustion of Magnegases

    CERN Document Server

    Santilli, R M


    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...

  1. Sorbitol as an arrester of embryonic development in diapausing eggs of the silkworm, Bombyx mori. (United States)

    Horie; Kanda; Mochida


    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.

  2. 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


    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。


    Directory of Open Access Journals (Sweden)

    L. P. Buchatsky


    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.

  4. 西安市引湑济黑调水工程黑老路桥梁工程冬季施工保温措施研究%Heat Preservation Measures in Winter Construction for Heflaolu Bridge Engineering of Xushuihe-to-Heihe Water Transfer Project in Xi'an City

    Institute of Scientific and Technical Information of China (English)



    引湑济黑桥梁工程冬季施工保温是确保施工质量的关键工作。分析了中小型桥梁工程冬季施工的保温措施,提出了针对工程具体结构特点,以提高入仓温度、蓄热保温为主,掺加防冻剂为辅,多种措施并用的防冻保温措施,对同类工程的施工具有参考意义。%The heat preservation in winter construction of the bridge engineering in Xushuihe-to-Heihe Water Transfer Project is the key to ensure the construction quality. Here, the heat preservation measures of small and medium bridge engineerings in winter construction are analyzed. At the same time, the comprehensive measures for frost protection and heat preservation, with the improvement of concrete pouring temperature and thermal insulation as the main measure and with the mixing of antifreeze as the auxiliary measure, are put forward according to the engineering structure characteris- tics, which would have reference value for the construction of similar projects.

  5. Biological conversion of gaseous alkenes to liquid chemicals. (United States)

    Desai, Shuchi H; Koryakina, Irina; Case, Anna E; Toney, Michael D; Atsumi, Shota


    Industrial gas-to-liquid (GTL) technologies are well developed. They generally employ syngas, require complex infrastructure, and need high capital investment to be economically viable. Alternatively, biological conversion has the potential to be more efficient, and easily deployed to remote areas on relatively small scales for the utilization of otherwise stranded resources. The present study demonstrates a novel biological GTL process in which engineered Escherichia coli converts C2-C4 gaseous alkenes into liquid diols. Diols are versatile industrially important chemicals, used routinely as antifreeze agents, polymer precursors amongst many other applications. Heterologous co-expression of a monooxygenase and an epoxide hydrolase in E. coli allows whole cell conversion of C2-C4 alkenes for the formation of ethylene glycol, 1,2-propanediol, 1,2-butanediol, and 2,3-butanediol at ambient temperature and pressure in one pot. Increasing intracellular NADH supply via addition of formate and a formate dehydrogenase increases ethylene glycol production titers, resulting in an improved productivity of 9mg/L/h and a final titer of 250mg/L. This represents a novel biological method for GTL conversion of alkenes to industrially valuable diols.

  6. Parallel ecological diversification in Antarctic notothenioid fishes as evidence for adaptive radiation. (United States)

    Rutschmann, Sereina; Matschiner, Michael; Damerau, Malte; Muschick, Moritz; Lehmann, Moritz F; Hanel, Reinhold; Salzburger, Walter


    Antarctic notothenioid fishes represent a rare example of a marine species flock. They evolved special adaptations to the extreme environment of the Southern Ocean including antifreeze glycoproteins. Although lacking a swim bladder, notothenioids have diversified from their benthic ancestor into a wide array of water column niches, such as epibenthic, semipelagic, cryopelagic and pelagic habitats. Applying stable carbon (C) and nitrogen (N) isotope analyses to gain information on feeding ecology and foraging habitats, we tested whether ecological diversification along the benthic-pelagic axis followed a single directional trend in notothenioids, or whether it evolved independently in several lineages. Population samples of 25 different notothenioid species were collected around the Antarctic Peninsula, the South Orkneys and the South Sandwich Islands. The C and N stable isotope signatures span a broad range (mean δ(13) C and δ(15) N values between -25.4‰ and -21.9‰ and between 8.5‰ and 13.8‰, respectively), and pairwise niche overlap between four notothenioid families was highly significant. Analysis of isotopic disparity-through-time on the basis of Bayesian inference and maximum-likelihood phylogenies, performed on a concatenated mitochondrial (cyt b) and nuclear gene (myh6, Ptr and tbr1) data set (3148 bp), showed that ecological diversification into overlapping feeding niches has occurred multiple times in parallel in different notothenioid families. This convergent diversification in habitat and trophic ecology is a sign of interspecific competition and characteristic for adaptive radiations.

  7. Annealing condition influences thermal hysteresis of fungal type ice-binding proteins. (United States)

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


    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.

  8. Antarctomyces pellizariae sp. nov., a new, endemic, blue, snow resident psychrophilic ascomycete fungus from Antarctica. (United States)

    de Menezes, Graciéle C A; Godinho, Valéria M; Porto, Bárbara A; Gonçalves, Vívian N; Rosa, Luiz H


    In the present study, we have identified and characterised a new snow resident ascomycete blue stain fungus from Antarctica named Antarctomyces pellizariae sp. nov. Menezes, Godinho, Porto, Gonçalves and Rosa, using polyphasic taxonomy techniques. This fungal species was recovered from the seasonal snow of the Antarctic Peninsula. Antarctomyces pellizariae displayed different macro- and micromorphology when compared with A. psychrotrophicus Stchigel and Guarro, the only other Antarctomyces species reported until date. Antarctomyces pellizariae showed psychrophilic behavior and very low growth rate at 22-25 °C, quite different from A. psychrotrophicus that has a higher growth rate at mesophilic temperatures. In addition, micromorphological characteristics and the analysis of the nuclear rDNA internal transcribed spacer, β-tubulin, and RNA polymerase II regions revealed that A. pellizariae is a new species that is related to A. psychrotrophicus and Thelebolus species. Since the Antarctic Peninsula is reported to be one of the main regions of the earth experiencing the effects of global change in climate, species, such as A. pellizariae, might provide information about these effects on the endemic Antarctic biota. In addition, A. pellizariae displayed psychrophilic behavior and might be a source of interesting anti-freeze compounds that might prove useful in biotechnological processes.

  9. 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


    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.

  10. Detection of ethylene glycol - toward W51/e2 and G34.3+0.02 (United States)

    Lykke, Julie M.; Favre, Cécile


    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.

  11. A novel GH secretagogue, A233, exhibits enhanced growth activity and innate immune system stimulation in teleosts fish. (United States)

    Martinez, Rebeca; Ubieta, Kenia; Herrera, Fidel; Forellat, Alina; Morales, Reynold; de la Nuez, Ania; Rodriguez, Rolando; Reyes, Osvaldo; Oliva, Ayme; Estrada, Mario P


    In teleosts fish, secretion of GH is regulated by several hypothalamic factors that are influenced by the physiological state of the animal. There is an interaction between immune and endocrine systems through hormones and cytokines. GH in fish is involved in many physiological processes that are not overtly growth related, such as saltwater osmoregulation, antifreeze synthesis, and the regulation of sexual maturation and immune functions. This study was conducted to characterize a decapeptide compound A233 (GKFDLSPEHQ) designed by molecular modeling to evaluate its function as a GH secretagogue (GHS). In pituitary cell culture, the peptide A233 induces GH secretion and it is also able to increase superoxide production in tilapia head-kidney leukocyte cultures. This effect is blocked by preincubation with the GHS receptor antagonist [d-Lys(3)]-GHRP6. Immunoneutralization of GH by addition of anti-tilapia GH monoclonal antibody blocked the stimulatory effect of A233 on superoxide production. These experiments propose a GH-mediated mechanism for the action of A233. The in vivo biological action of the decapeptide was also demonstrated for growth stimulation in goldfish and tilapia larvae (P<0.001). Superoxide dismutase levels, antiprotease activity, and lectin titer were enhanced in tilapia larvae treated with this novel molecule. The decapeptide A233 designed by molecular modeling is able to function as a GHS in teleosts and enhance parameters of the innate immune system in the fish larvae.

  12. 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


    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.

  13. Ice slurry accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Christensen, K.G.; Kauffeld, M.


    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)

  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


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


    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.

  16. 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.


    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.

  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


    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. Classical Behavior of Alumina (Al2O3 Nanofluids in Antifrogen N with Experimental Evidence

    Directory of Open Access Journals (Sweden)

    M. Saleemi


    Full Text Available A nanofluid is a suspension containing nanoparticles in conventional heat transfer fluids. This paper reports on an investigation of alumina (Al2O3 nanoparticles in Antifrogen N, also called AFN, which is a popular antifreeze coolant consisting primarily of ethylene glycol and other additives to impede corrosion. The base carrier fluid is 50% by weight of water and 50% by weight of AFN. We systematically measured the nanomaterials and heat transfer data of nanofluids for four different size particles, namely, 20, 40, 150, and 250 nm alumina particles. The pH of all the nanofluids is adjusted to have a stable dispersion. The material characterizations include SEM and DLS particle measurements. We measured thermal conductivity, viscosity, and heat transfer coefficient in developing flow of the nanofluids. We observed that these nanofluids behave as any other classical fluids in thermally developing flow and classical heat transfer correlations can be used to completely describe the characteristics of these nanofluids.

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

    Directory of Open Access Journals (Sweden)

    Walker Virginia K


    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.

  20. 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


    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.

  1. Probing protein-sugar interactions. (United States)

    Ebel, C; Eisenberg, H; Ghirlando, R


    We have investigated the partial specific volumes (2) (ml/g), hydration, and cosolvent interactions of rabbit muscle aldolase by equilibrium sedimentation in the analytical ultracentrifuge and by direct density increment (partial differential/partial differentialc(2))(mu) measurements over a range of sugar concentrations and temperature. In a series of sugars increasing in size, glucose, sucrose, raffinose, and alpha-cyclodextrin, (partial differential/ partial differentialc(2))(mu) decreases linearly with the solvent density rho(0). These sugar cosolvents do not interact with the protein; however, the interaction parameter B(1) (g water/g protein) mildly increases with increasing sugar size. The experimental B(1) values are smaller than values calculated by excluded volume (rolling ball) considerations. B(1) relates to hydration in this and in other instances studied. It decreases with increasing temperature, leading to an increase in (2) due to reduced water of hydration electrostriction. The density increments (partial differential/ partial differentialc(2))(mu), however, decrease in concave up form in the case of glycerol and in concave down form for trehalose, leading to more complex behavior in the case of carbohydrates playing a biological role as osmolytes and antifreeze agents. A critical discussion, based on the thermodynamics of multicomponent solutions, is presented.

  2. 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.

  3. 双层排水路面在遂资眉高速公路工程中的应用%Application of Double Drainage Asphalt Pavement in Sui Zimei Highway Engineering

    Institute of Scientific and Technical Information of China (English)

    王毅; 唐国奇; 魏娟; 张姣; 廖飞


    Compared with conventional single-layer drainage asphalt pavement structure,double drain-age pavement structure system has great advantages in noise reduction,anti-slide,drainage,antifreeze and durability.Based on the engineering application of double drainage asphalt pavement in Sui Zimei highway engineering,the double-layer drainage asphalt mix design and performance test are investiga-ted in this paper.Finally a detailed introduction of construction technology is presented.%双层排水路面结构体系相对于传统的单层排水沥青路面结构在降噪、抗滑、排水、抗冻及耐久性等方面具有较大的优势。文中通过双层排水降噪沥青路面在遂资眉高速公路工程中的实际应用,对双层排水性沥青混合料的配合比设计及其性能进行了试验测试分析,并就工程施工的要点进行了总结。


    Directory of Open Access Journals (Sweden)

    Pedro Samuel Gomes Medeiros


    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.

  5. 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)


    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.)

  6. Extremophiles and their application to veterinary medicine

    Directory of Open Access Journals (Sweden)

    Irwin Jane A


    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.

  7. Biodiversity and cold adaptive mechanisms of psychrophiles

    Directory of Open Access Journals (Sweden)

    Yuhua Xin


    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.

  8. 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


    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.

  9. 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


    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.

  10. Elevated osmolytes in rainbow smelt: the effects of urea, glycerol and trimethylamine oxide on muscle contractile properties. (United States)

    Coughlin, David J; Long, Gabrielle M; Gezzi, Nicole L; Modi, Parth M; Woluko, Kossivi N


    Rainbow smelt, Osmerus mordax, experience a wide range of temperatures in their native habitat. In response to cold, smelt express anti-freeze proteins and the osmolytes glycerol, trimethylamine N-oxide (TMAO) and urea to avoid freezing. The physiological influences of these osmolytes are not well understood. Urea destabilizes proteins, while TMAO counteracts the protein-destabilizing forces of urea. The influence of glycerol on muscle function has not been explored. We examined the effects of urea, glycerol and TMAO through muscle mechanics experiments with treatments of the three osmolytes at physiological concentrations. Experiments were carried out at 10°C. The contractile properties of fast-twitch muscle bundles were determined in physiological saline and in the presence of 50 mmol l(-1)urea, 50 mmol l(-1)TMAO and/or 200 mmol l(-1)glycerol in saline. Muscle exposed to urea and glycerol produced less force and displayed slower contractile properties. However, treatment with TMAO led to higher force and faster relaxation by muscle bundles. TMAO increased power production during cyclical activity, while urea and glycerol led to reduced oscillatory power output. When muscle bundles were exposed to a combination of the three osmolytes, they displayed little change in contraction kinetics relative to control, although power output under lower oscillatory conditions was enhanced while maximum power output was reduced. The results suggest that maintenance of muscle function in winter smelt requires a balanced combination of urea, glycerol and TMAO.

  11. Performance monitoring of a bubble pumped solar domestic hot water system - final report

    Energy Technology Data Exchange (ETDEWEB)

    Makuch, P.D.; Harrison, S.J. [Queen`s Univ., Kingston, ON (Canada). Solar Calorimetry Lab.


    A new type of solar domestic hot water (SDHW) system for cold climates was described. The bubble pump system is self pumping and self regulating (it circulates anti-freeze). The system transports heat from roof mounted solar collectors to a thermal storage located at a lower level when there is available solar radiation. The design is unique in that it has no moving parts and requires no external electrical or mechanical input to operate. A unit was installed on a row house in Kingston, Ontario, to evaluate its performance. The average daily solar fraction was 32.4 per cent, and the average system efficiency for the monitored period was 13.4 per cent. This was below expectations due to low hot water demand. Performance improved somewhat towards the end of the monitoring period due to increased demand for hot water, improvements to the system, and increased solar insulation. A more realistic annual performance was estimated at 19 per cent for system efficiency and 41 per cent for solar fraction. Further improvements could be expected, especially in mid-winter performance, if the solar collector slope could be increased to a value of 45 to 60 degrees to the horizontal. 8 refs., 14 tabs., 9 figs.

  12. Angle-resolved diffraction grating biosensor based on porous silicon (United States)

    Lv, Changwu; Jia, Zhenhong; Liu, Yajun; Mo, Jiaqing; Li, Peng; Lv, Xiaoyi


    In this study, an optical biosensor based on a porous silicon composite structure was fabricated using a simple method. This structure consists of a thin, porous silicon surface diffraction grating and a one-dimensional porous silicon photonic crystal. An angle-resolved diffraction efficiency spectrum was obtained by measuring the diffraction efficiency at a range of incident angles. The angle-resolved diffraction efficiency of the 2nd and 3rd orders was studied experimentally and theoretically. The device was sensitive to the change of refractive index in the presence of a biomolecule indicated by the shift of the diffraction efficiency spectrum. The sensitivity of this sensor was investigated through use of an 8 base pair antifreeze protein DNA hybridization. The shifts of the angle-resolved diffraction efficiency spectrum showed a relationship with the change of the refractive index, and the detection limit of the biosensor reached 41.7 nM. This optical device is highly sensitive, inexpensive, and simple to fabricate. Using shifts in diffraction efficiency spectrum to detect biological molecules has not yet been explored, so this study establishes a foundation for future work.

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


    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.

  14. Inhibition of ice growth and recrystallization by zirconium acetate and zirconium acetate hydroxide. (United States)

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


    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.

  15. Ice Recrystallization in a Solution of a Cryoprotector and Its Inhibition by a Protein: Synchrotron X-Ray Diffraction Study. (United States)

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


    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.

  16. Ice-crust and ice-film; Miaraban

    Energy Technology Data Exchange (ETDEWEB)

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


    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)

  17. Growth kinetics of microorganisms isolated from Alaskan soil and permafrost in solid media frozen down to -35 degrees C. (United States)

    Panikov, Nicolai S; Sizova, Maria V


    We developed a procedure to culture microorganisms below freezing point on solid media (cellulose powder or plastic film) with ethanol as the sole carbon source without using artificial antifreezes. Enrichment from soil and permafrost obtained on such frozen solid media contained mainly fungi, and further purification resulted in isolation of basidiomycetous yeasts of the genera Mrakia and Leucosporidium as well as ascomycetous fungi of the genus Geomyces. Contrary to solid frozen media, the enrichment of liquid nutrient solutions at 0 degrees C or supercooled solutions stabilized by glycerol at -1 to -5 degrees C led to the isolation of bacteria representing the genera Polaromonas, Pseudomonas and Arthrobacter. The growth of fungi on ethanol-microcrystalline cellulose media at -8 degrees C was exponential with generation times of 4.6-34 days, while bacteria displayed a linear or progressively declining curvilinear dynamic. At -17 to -0 degrees C the growth of isolates and entire soil community on 14C-ethanol was continuous and characterized by yields of 0.27-0.52 g cell C (g of C-substrate)(-1), similar to growth above the freezing point. The 'state of maintenance,' implying measurable catabolic activity of non-growing cells, was not confirmed. Below -18 to -35 degrees C, the isolated organisms were able to grow only transiently for 3 weeks after cooling with measurable respiratory and biosynthetic (14CO2 uptake) activity. Then metabolic activity declined to zero, and microorganisms entered a state of reversible dormancy.

  18. Partial results summary for solar domestic hot water monitoring in Pennsylvania (United States)

    Aungst, W. K.

    Installation procedures, monitoring practices, and results of performance evaluations of 50 HUD-sponsored residential solar flat plate collector systems studied in the field are summarized. The systems consisted of antifreeze, drain-down, and air freeze protection schemes, featured either one- or two-tank thermal storage, and were either roof- or ground-mounted. Residents kept daily records of water flow, temperature, kWh, and elapsed time. The HUD program goals were that one-half of the household daily water needs would be heated by the solar system. An average of 34.5% of the hot water energy was found, although a coefficient of performance of 1.40 was also found, compared to 0.78 and 0.82 for nonsolar water heaters. An average of 9% rate of return on investment was calculated for the solar systems, noting that system efficiencies ranged from 7-79.8%, and the rates of return ranged from 1-22.4%.

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


    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.

  20. Toxic optic neuropathy: An unusual cause

    Directory of Open Access Journals (Sweden)

    Hema L Ramkumar


    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.

  1. Durham Nursing Home solar project: a case study

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  2. 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


    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

  3. 高海拔地区土石坝技术研究%Study of Key Technology of Earth-Rock Dam in High Altitude Areas

    Institute of Scientific and Technical Information of China (English)

    张宝琼; 林赛; 陈红齐


    香格里拉县桑那水库是云南省第一座在高海拔3300 m的高寒地区修建的中型水库,当地冬季气温低(最低气温-27.4℃),对坝基开挖、填筑、混凝土浇筑施工带来很大影响,设计提出:1)混凝土盖板及坝基保护采取引水保护,水与岸坡结合部位易形成冰冻,对这部分采取塑料薄膜加石碴覆盖;2)土料避开低温期施工,在施工中随时检查粘土含水量,在料场采取挖排水沟,开挖过的土料场上以及填筑好的防渗心墙上覆盖三色塑料薄膜加渣料作保护等保温防冻措施;3)在永久暴露混凝土表面配置温度钢筋,浇筑混凝土时掺入抗冻剂、减水剂、速凝剂,同时采取保温措施。%Located in Shangri-La county,Sangna reservoir, a medium-sized water-conservancy project,is the first medium reservoir built in extremely cold areas at an altitude of 3 300 meters. The local temperature in winter is low (the minimum temperature is 27.4 degrees),which severely affects the founda-tion excavation,filling and concrete pouring for the damming The design in this paper proposes the following countermeasures:1) we could use water to protect the concrete cover and dam foundation;and cover the combination parts between water and bank(where freezing can be easily formed)with plastic film and ballast;2)As for the earth material,we could avoid construct-ing in low temperatures and check the clay moisture frequently during construction;and dig ditches in the stock field and cover the field for anti-freezing protection with three-color plastic film and ballast;3)we could take measures to keep the concrete warm in the process of pouring by mixing it with antifreeze agent,water reducing agent and at the same time use temperature rebar on the surface of the permanent exposed concrete.

  4. 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


    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

  5. 白云石粉用作矿物掺合料对混凝土耐久性的影响

    Institute of Scientific and Technical Information of China (English)

    贾丽莉; 高育欣; 赵日煦; 彭园; 黄义雄; 霍亮


    The ground dolomite and co-grinding powders of dolomite and water-quendched granulated blost furnace slag were used as concrete admixtures, and the influence of admixture on the durability of concrete are studied. The results show that by single-mixed with dolomite powder, the electric flux of C30 concrete increase by 15%, the carbonation depth increase, and the loss rate of dynamic elastic modulus can reach up to 37.6% after 100 freeze-thaw cycles, the properties of chloride ion penetration-resistant, anti-carbonization and anti-freeze of concrete are weakened;however, the sulphate resistance coefficient of concrete increase by 1.7%, the sulfate resistance is improved. Compared with single-mixed dolomite powder, mixing dolomite-slag composite mineral admixture can improve properties of chloride ion penetration-resistant, anti-carbonization and anti-freeze of concrete, especially when the ratio of slag and dolomite is 3.5:6.5, the durability of concrete will be the best.%用磨细白云石、白云石-水淬矿渣共磨物料作为混凝土矿物掺合料,研究了单掺白云石粉、白云石-水淬矿渣复合矿物掺合料对混凝土耐久性的影响。研究结果表明,单掺白云石粉使C30混凝土的电通量值增加15%,同时使碳化深度增加,并使100次冻融循环后的动弹模量损失率最大达到37.6%,弱化了混凝土的抗氯离子侵蚀性和抗碳化和抗冻性能;而单掺白云石粉使混凝土的抗硫酸盐侵蚀系数提高1.7%,抗硫酸盐侵蚀性能改善。白云石-水渣复合矿物掺合料与单掺白云石粉相比,改善了混凝土的抗氯离子渗透性、抗碳化、抗冻融性能;当水淬矿渣与白云石比例为3.5:6.5时,混凝土的耐久性包括抗氯离子侵蚀性、抗碳化、抗冻性能最好。

  6. 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)



    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。

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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

  8. The Pharmacological Properties and Therapeutic Use of Apomorphine

    Directory of Open Access Journals (Sweden)

    Samo Ribarič


    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.

  9. Experimental investigation and planetary implications of the stability of clathrate hydrates in aqueous solution at icy satellite conditions (United States)

    Dunham, M.; Choukroun, M.; Barmatz, M.; Hodyss, R. P.; Smythe, W. D.


    Clathrate hydrates consist of hydrogen-bonded water molecules forming cages in which gas molecules are trapped individually. They are among the favored volatile reservoirs in solar system bodies, and are expected to play an important role in many processes: accretion of volatiles in planetesimals, outgassing on Titan, Enceladus, and comets. Their insulating thermal properties and high mechanical strength also bear important implications for understanding the evolution of icy satellites like Europa. However, the conditions allowing for their formation and/or their dissociation and the release of volatiles to the atmosphere (Titan) or the plumes (Enceladus) are still poorly understood. This is mainly because of a lack of knowledge on the stability of mixed clathrate hydrates in presence of anti-freeze agents such as ammonia. We have developed a high-pressure cryogenic calorimeter to address this deficiency in the literature. This liquid nitrogen - cooled Setaram BT2.15 calorimeter is located at the JPL Ice Physics Laboratory. The temperature range achievable with this instrument is 77-473 K. This calorimeter uses Calvet elements (3D arrays of thermocouples) to measure the heat flow required to follow a predefined heating rate within a sample and a reference cell with a resolution of 0.1 μW. A gas handling system has been designed and fabricated in house to reach pressures up to 100 bars, corresponding to several km depth in icy satellites. The thermodynamic properties of CO2 and CH4 clathrates with ammonia are under investigation, and the results will be used to constrain a statistical thermodynamic model of clathrates for applications to planetary environments. Preliminary results will be shown at the meeting. This work has been conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. Support from the Minnesota Space Grant Consortium, the NASA Outer Planets Research program, and government sponsorship are gratefully

  10. 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


    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.

  11. Aircraft de-icer: Recycling can cut carbon emissions in half

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Eric P., E-mail:


    Flight-safety regulations in most countries require aircraft to be ice-free upon takeoff. In icy weather, this means that the aircraft usually must be de-iced (existing ice is removed) and sometimes anti-iced (to protect against ice-reformation). For both processes, aircraft typically are sprayed with an 'antifreeze' solution, consisting mainly of glycol diluted with water. This de/anti-icing creates an impact on the environment, of which environmental regulators have grown increasingly conscious. The US Environmental Protection Agency (EPA), for example, recently introduced stricter rules that require airports above minimum size to collect de-icing effluents and send them to wastewater treatment. De-icer collection and treatment is already done at most major airports, but a few have gone one step further: rather than putting the effluent to wastewater, they recycle it. This study examines the carbon savings that can be achieved by recycling de-icer. There are two key findings. One, recycling, as opposed to not recycling, cuts the footprint of aircraft de-icing by 40-50% - and even more, in regions where electricity-generation is cleaner. Two, recycling petrochemical-based de-icer generates a 15-30% lower footprint than using 'bio' de-icer without recycling. - Highlights: Black-Right-Pointing-Pointer Carbon footprint of aircraft de-icing can be measured. Black-Right-Pointing-Pointer Recycling aircraft de-icer cuts the footprint of aircraft de-icing by 40-50%. Black-Right-Pointing-Pointer Recycling 'fossil' de-icer is lower carbon than not recycling 'bio' de-icer.

  12. 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


    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.

  13. The effects of AP521, a novel anxiolytic drug, in three anxiety models and on serotonergic neural transmission in rats. (United States)

    Kasahara, Ken-Ichi; Hashimoto, Shinji; Hattori, Tsuyoshi; Kawasaki, Koh; Tsujita, Ryuichi; Nakazono, Osamu; Takao, Katsuyuki; Kawakubo, Hiromu; Nagatani, Tadashi


    We investigated the anxiolytic effects and mechanism of action of a new anxiolytic drug, (R)-piperonyl-1,2,3,4-tetrahydro[1]benzothieno[2,3-c]pyridine-3- carboxamide hydrochloride (AP521). AP521 showed equal or more potent anxiolytic-like effects compared with diazepam, a benzodiazepine receptor agonist, or tandospirone, a partial 5-hydroxytryptamine (5-HT)1A receptor agonist, in three rat anxiety models; the Vogel-type conflict test, elevated plus maze test, and conditioned fear stress test. Although AP521 did not bind to the benzodiazepine receptor, it did bind to 5-HT1A, 5-HT1B, 5-HT1D, 5-HT5A and 5-HT7 receptors, and showed agonist activity for the human 5-HT1A receptor expressed in HEK293 cells. Tandospirone, which can stimulate the presynaptic 5-HT1A receptors in the raphe, tended to decrease extracellular 5-HT concentration in the medial prefrontal cortex (mPFC) in rats. In contrast, AP521 increased extracellular 5-HT concentration. In addition, AP521 enhanced the anti-freezing effect of citalopram, a selective serotonin reuptake inhibitor, in the fear conditioning model in rats and enhanced the citalopram-caused increase of the extracellular 5-HT concentration in the mPFC. These results suggest that AP521 exhibits potent anxiolytic effects by acting as a postsynaptic 5-HT1A receptor agonist and by enhancing serotonergic neural transmission in the mPFC by a novel mechanism of action.

  14. [Application of solidification technology in ecological protection of rural riverbank]. (United States)

    Fu, Rong-bing; Chen, Xiao-hua; Luo, Qi-shi; Zhang, Shu-jiu; Li, Xiao-ping; Geng, Chun-nü


    A self-developed binder was used for the solidification of construction refuse piles and whole soil matrix, and a technology of this solidification combining with grass-planting was adopted to ecologically protect the rural riverbanks at Tianshan Village of Shanghai. This technology and other ecological engineering techniques were also employed to reconstruct the ecological environment of a sewage pond at the Village. The results showed that the solidified piles had an anti-compression strength of up to 7.3 MPa, with good hydraulic permeability, fast hardening rate, and low drying shrinkage, which met the requirements for ecological safety. The solidified stakes could be used at a low temperature of above -18 degrees C with addition of certain anti-freezing agents. The riverbank underpinned with the solidified stakes had higher anti-compressive strength, higher ability of anti-soil erosion, and better hydraulic permeability; and its soil had the similar moisture content to bare riverbank soil, with no detrimental effects on the root growth of planted grass. After soil solidification, the shearing strength of the riverbank increased by 50 times, and its soil loss was only 5% of the bare riverbank. In the first 10 days after adopting this technology, parts of Cynodon dactylon roots on the surface of solidified soil matrix began to extend into soil; after one month, 60% of the roots penetrated into deeper soil layer; and 11 months later, the grass roots completely grew in-depth in the soil. The combination of our solidification technique with vegetation reconstruction satisfied the requirements of both stabilizing riverbank and improving riparian habitat.

  15. Phase behavior in the system tetrahydrofuran-water-ammonia from calorimetry and Raman spectroscopy (United States)

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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)



    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.

  17. Common protein sequence signatures associate with Sclerotinia borealis lifestyle and secretion in fungal pathogens of the Sclerotiniaceae

    Directory of Open Access Journals (Sweden)

    Thomas eBadet


    Full Text Available Fungal plant pathogens produce secreted proteins adapted to function outside fungal cells to facilitate colonization of their hosts. In many cases such as for fungi from the Sclerotiniaceae family the repertoire and function of secreted proteins remains elusive. In the Sclerotiniaceae, whereas Sclerotinia sclerotiorum and Botrytis cinerea are cosmopolitan broad host-range plant pathogens, Sclerotinia borealis has a psychrophilic lifestyle with a low optimal growth temperature, a narrow host range and geographic distribution. To spread successfully, S. borealis must synthesize proteins adapted to function in its specific environment. The search for signatures of adaptation to S. borealis lifestyle may therefore help revealing proteins critical for colonization of the environment by Sclerotiniaceae fungi. Here, we analyzed amino acids usage and intrinsic protein disorder in alignments of groups of orthologous proteins from the three Sclerotiniaceae species. We found that enrichment in Thr, depletion in Glu and Lys, and low disorder frequency in hot loops are significantly associated with S. borealis proteins. We designed an index to report bias in these properties and found that high index proteins were enriched among secreted proteins in the three Sclerotiniaceae fungi. High index proteins were also enriched in function associated with plant colonization in S. borealis, and in in planta-induced genes in S. sclerotiorum. We highlight a novel putative antifreeze protein and a novel putative lytic polysaccharide monooxygenase identified through our pipeline as candidate proteins involved in colonization of the environment. Our findings suggest that similar protein signatures associate with S. borealis lifestyle and with secretion in the Sclerotiniaceae. These signatures may be useful for identifying proteins of interest as targets for the management of plant diseases.

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

    Directory of Open Access Journals (Sweden)

    Marino Vacchi


    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.

  19. 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)


    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)

  20. "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


    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

  1. Study of fuel consumption and cooling system in low heat rejection turbocharged diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Taymaz, I.; Gur, M.; Cally, I.; Mimaroglu, A.


    In a conventional internal combustion engine, approximately one-third of total fuel input energy is converted to useful work. Since the working gas in a practical engine cycle is not exhausted at ambient temperature, a major part of the energy is lost with the exhaust gases. In addition another major part of energy input is rejected in the form of heat via the cooling system. If the energy normally rejected to the coolant could be recovered instead on the crankshaft as useful work, then a substantial improvement in fuel economy would result. At the same time, the cooling water, antifreeze, thermostat, radiator, water pump, cooling fan, and associated hoses and clamps could be eliminated. A new trend in the field of internal combustion engines is to insulate the heat transfer surfaces such as the combustion chamber, cylinder wall, cylinder head, piston and valves by ceramic insulating materials for the improvement of engine performance and elimination of cooling system. In this study, the effect of insulated heat transfer surfaces on direct injected and turbocharged diesel engine fuel consumption and cooling system were investigated. The research engine was a four-stroke, direct injected, six cylinder, turbocharged and intercooled diesel engine. This engine was tested at different speeds and loads conditions without coating. Then, combustion chamber surfaces, cylinder head, valves and piston crown faces was coated with ceramic materials. Ceramic layers were made of CaZrO{sub 3} and MgZrO{sub 3} and plasma coated onto base of the NiCrAl bond coat. The ceramic coated research engine was tested at the same operation conditions as the standard (without coating) engine. The results indicate a reduction in fuel consumption and heat losses to engine cooling system of the ceramic coated engine.

  2. Ethylene glycol toxicity presenting with non-anion gap metabolic acidosis. (United States)

    Soghoian, Sari; Sinert, Richard; Wiener, Sage W; Hoffman, Robert S


    Ethylene glycol classically produces an elevated anion gap metabolic acidosis. We report a series of patients with ethylene glycol toxicity with a component of non-anion gap metabolic acidosis without known associated confounding factors. A retrospective review of Poison Control Center records were searched more than 8 years (2000-2007) for ethylene glycol and antifreeze. Cases were reviewed and excluded for miscoding, information calls, animal exposures, or non-ingestion exposures. The bicarbonate gap, or delta ratio (DR), was calculated using the formula: DR = (AG - 12)/[24 - measured serum where anion gap (AG) = [Na(+)] - [Cl(-)] - , all in mEq/l. Non-anion gap metabolic acidosis was considered present when the DR metabolic acidosis at presentation. Their calculated anion gap was 14-28, and measured serum ranged from 2-20 mEq/l. A normal anion gap was present in two patients who presented with non-anion gap metabolic acidosis. The DR ranged from 0.28-0.95. Seven out of 14 patients with non-anion gap metabolic acidosis had elevated serum [Cl(-)]. In the other cases, no explanation for the non-anion gap metabolic acidosis could be determined. The absence of a significant anion gap elevation in the setting of metabolic acidosis after ethylene glycol ingestion without other confounding factors (such as ethanol, lithium carbonate or bromide) has not previously been recognized. Clinicians should be aware of the potential for non-anion gap metabolic acidosis in patients with ethylene glycol toxicity, and should not exclude the diagnosis in patients who present with a non-anion gap metabolic acidosis. Further study is needed to determine the mechanisms by which this occurs.

  3. 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)


    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.

  4. 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)


    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.

  5. 5%三氟氯氰菊酯水乳剂的安全环保配方%Research on Cyhalothrin 5% EW Formulation

    Institute of Scientific and Technical Information of China (English)

    张保华; 潘淑翠; 王智; 王琼


    [目的]开发安全环保的5%三氟氯氰菊酯水乳剂.[方法]采用相转移法,对溶剂及表面活性剂进行筛选,确定5%三氟氯氰菊酯水乳剂的最优配方.[结果]最优配方:三氟氯氰菊酯5%,溶剂二甲苯10%,602#乳化剂6%,OP-10-P乳化剂2%,乙二醇5%,消泡剂0.1%,水补足.经常温、热贮(54±2)℃,14 d未出现析油、分层现象,有效成分分解率<5%,制剂黏度小.[结论]5%三氟氯氰菊酯水乳剂各项指标均符合水乳剂的要求,具有良好的开发前景.%[Aims] The cyhalothrin 5% emulsion in water (EW) was developed for safety and environmental protection. [Methods] The optimum formulation was determined through the phase transfer method and the screening solvent and surfactant. [Results] The favorable formulation of cyhalothrin 5% EW consisted of cyhalothrin 5%, xylene 10%, 602# emulsifie 6%, OP-10-P emulsifier 2%, anti-freeze agents glycol 5%, antifoaming agents 0.1% and water. The cyhalothrin 5% EW had been stored at normal temperature and (54±2) ℃ for 14 d without oil and layer separation, and the decomposition rate of the active ingredient was less than 5%. The viscosity of the formulation was low. [Conclusions] The cyhalothrin 5% EW accorded with the criterions and requirements of the EW and maight have a good prospect.

  6. Oil palm EgCBF3 conferred stress tolerance in transgenic tomato plants through modulation of the ethylene signaling pathway. (United States)

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


    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.

  7. Immunochemical studies on the N-acetyllactosamine beta-(1----6)-linked trisaccharide specificity of Ricinus communis agglutinin. (United States)

    Wu, A M; Sugii, S; Gruezo, F G; Kabat, E A


    The combining site of Ricinus communis agglutinin (RCA1) was studied by quantitative precipitin and precipitin inhibition assays. Of 31 complex carbohydrates tested, all except active and inactive antifreeze glycoproteins, Streptococcus group C polysaccharide, and native rat salivary glycoprotein, reacted strongly, and 22 completely precipitated the lectin, indicating that RCA1 has both a broad range of affinity and a low solubility of its carbohydrate-bound complex. Of the monosaccharides and glycosides tested for inhibition of precipitation, p-nitrophenyl beta-D-galactopyranoside was the best. It was about 6.4 times better than methyl beta-D-galactopyranoside. The beta anomer of glycosides of D-galactose was much more potent than the corresponding alpha anomer. Among the oligosaccharides tested, beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----6)-D-Gal was the best inhibitor, which was approximately 2/3 as active as p-nitrophenyl beta-D-galactopyranoside. It was approximately 1.4 times as active as beta-D-Gal-(1----4)-D-GlcNAc (N-acetyllactosamine), twice as active as beta-D-Gal-(1----3)-D-GlcNAc, and 4.5 times more active than lacto-N-tetraose. From the results, it can be concluded that; (a) hydrophobic interaction is important for binding; (b) the combining site of this lectin is at least as large as a trisaccharide; and (c) of the compounds studied, the trisaccharide beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----6)-D-Gal was the most complementary to the human blood group I Ma determinant beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----6)-D-Gal.

  8. 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)


    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.

  9. Transient freezing behavior in photophobic responses of Euglena gracilis investigated in a microfluidic device. (United States)

    Ozasa, Kazunari; Lee, Jeesoo; Song, Simon; Maeda, Mizuo


    We found that the transient freezing behavior in photophobic responses of Euglena gracilis is a good indicator of the metabolic status of the cells. The transient blue light photophobic responses of E. gracilis cells were investigated on-chip using a new measurement, 'trace momentum' (TM), to evaluate their swimming activity quantitatively in real time. When blue light of intensity >30 mW cm(-2) was repeatedly switched on and off, a large negative spike in the TM was observed at the onset of the 'blue-light-off' phase. Single-cell trace analysis at a blue light intensity of 40 mW cm(-2) showed that 48% (on average, n = 15) of tumbling Euglena cells ceased activity ('freezing') for 2-30 s at the onset of blue-light-off before commencing forward motion in a straight line (termed 'straightforward swimming'), while 45% smoothly commenced straightforward swimming without delay. The proportion of freezing Euglena cells depended on the blue light intensity (only 20% at 20 mW cm(-2)). When the cells were stimulated by four blue light pulses at the higher intensity, without pre-exposure, the transient freezing behavior was more prominent but, on repeating the stimuli after an 80 min interval in red light, the same cells did not freeze. This shows that the metabolism of the cells had changed to anti-freezing during the interval. The relationship between the interval time with/without light irradiation and the blue light adaptation was elucidated experimentally. The origin of the freezing behavior is considered to be a shortage of a metabolic substance that promotes smooth switching of flagellum movement from in situ rotation mode to a straightforward swimming mode.

  10. 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.


    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

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


    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. Differential Proteomic Analysis and Photosynthetic Characteristics of Winter Rapeseed under Low Temperature Stress%低温胁迫下白菜型冬油菜差异蛋白质组学及光合特性分析

    Institute of Scientific and Technical Information of China (English)

    刘自刚; 米超; 袁金海; 孙万仓; 曾秀存; 方彦; 王志江; 武军艳; 方园; 李学才


    Isolation and identification of the differentially expressed proteins in winter rapeseed at low temperature, laid a founda-tion for revealing the mechanism of cold resistance of winter rapa. The strong cold resistant winter rape Longyou 7 was used as experimental material. Two dimensional electrophoresis, mass spectrometry and retrieval techniques were used to compare the proteomic differences at low temperature (4℃, –4℃) and normal atmospheric temperature (25℃/20℃), and functions were analyzed by KO and KEGG. It was observed that Longyou 7 had subsided growth point, creeping stem, and closed or semi-closed stomata under low temperature. The 2-DE and PDQuest8.0.1 software analysis showed that the number of protein spots were 726 and 738, respectively. Compared with the normal temperature treatment, at the 4℃ treatment showed differential expression at 10 protein spots while didn’t at five protein. Eleven proteins were identified by MS MALDI-TOF-TOF mass spectrometry analysis. They are involved in carbohydrate metabolism, rugan metabolism, amino acid metabolism, organic acid metabolism, nucleic acid metabolism, signal transduction in cell and communication and other cellular processes. we found the high activity of antifreeze protein in Longyou 7 leaf protein extraction solution after low temperature treatment through ice crystal morphology microscopic observation. Five out of the 11 proteins identified were associated with photosynthesis. Under low temperature, ribulose 1,5-bisphosphate carboxylase (RuBPCase) activity and photosynthetic rate decreases in leaves of Longyou 7. Under the low tem-perature, the proteome of winter rape was significantly changed, and the specific protein was expressed. The decrease ofPn in leaves was related to the expression inhibition and the activity decrease of RuBPCase. The decrease ofPn in leaves was mainly caused by non stomatal limitation. High activity of antifreeze protein plays an important role in cold resistance

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

  14. 植物耐冷性基因工程%Genetic engineering of plant for cold tolerance

    Institute of Scientific and Technical Information of China (English)

    逯明辉; 陈劲枫


    Temperature not only determines the distribution of plant species but also affects the productivity and quality of crops.The mechanisms of cold tolerance in plants involved in many aspects,such as the change of composition of membrane lipids,the accumulation of compatible solutes,the enhanced activity of antioxidant enzymes and the induced expression of low temperature related genes.Cold tolerance in plant is controlled by multi-genes,and it is difficult to use conventional breeding approaches to improve the trait efficiently.The application of genetic engineering offers another feasible way in theory and practice to improve the cold tolerance.In this paper,the recent development of application of plant genetic engineering for cold tolerance in composition of membrane lipids,compatible solutes,antifreeze proteins,activity of antioxidant enzymes and transcriptional factors inducing the expression of plant low temperature related genes were summarized,aiming to provide some useful information and ideas to researchers who work on the plant breeding and the mechanism of cold stress.%温度决定物种的分布,同时还影响作物的产量和品质.植物耐冷的机制涉及到许多方面,包括膜脂组成的变化、可混溶溶质的积累、抗氧化酶活性的提高、低温相关基因的诱导表达等.由于植物的耐冷性状由多基因控制,采用传统的育种方法往往难以取得理想的结果,而植物基因工程技术的发展及应用则提供了另外可能的途径,可以通过转移耐冷性状形成的关键基因从而对植物进行改良.本文从膜脂组成、可混溶溶质、抗冻蛋白、抗氧化酶和诱导植物低温相关基因的转录因子等方面对植物耐冷性的基因工程研究进行了综述,以期为植物育种者和从事冷胁迫机制研究的工作者提供参考.

  15. Preparation of Non-toxic Bubble Water%无毒超大泡泡水的研制

    Institute of Scientific and Technical Information of China (English)

    陈志伟; 王华才; 邵雅文; 何书熬


    Bubble Water is one of the most favorite toys in daily life , which can bring many happiness to children . However, many bubble water products have some drawbacks , for example, they have strong pungent odor , which can also irritate skin.Therefore, excellent raw material such as foaming agents and antifreeze agent were well selected , safe product formula was designed using single factor method:Tween-40 10.0%, glucose 5.0%, glycerol 10.0%, deionized water 75.0%.The product was not only safe and accepted easily by many consumers , but also provided some reference for the subsequent development of bubble water products .%泡泡水是日常生活中最受儿童喜欢的玩具之一,然而市场上许多泡泡水产品存在有刺激性气味、对皮肤刺激等危害儿童健康的缺陷。为此,本文采用优良的制备原料,选用起泡剂、增效剂、持久剂、抗冻剂等组成成分,通过单因素法进行配方设计,制备出安全泡泡水产品,其配方为:吐温-40,10.0%;葡萄糖,2.0%;甘油,15.0%;去离子水,75.0%;防腐剂少量。本文研发的泡泡水产品安全无毒、价格适中易被大多数消费者所接受,同时也为泡泡水系列产品的后续开发提供了一定的借鉴意义。

  16. 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


    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.

  17. 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


    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.

  18. 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


    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.

  19. 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


    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

  20. Expression of endogenous and exogenous growth hormone (GH) messenger (m) RNA in a GH-transgenic tilapia (Oreochromis niloticus). (United States)

    Caelers, Antje; Maclean, Norman; Hwang, Gyulin; Eppler, Elisabeth; Reinecke, Manfred


    We have previously produced transgenic fish from crosses between a wild-type female tilapia (Oreochromis niloticus) and a G transgenic male. This line of growth-enhanced tilapia carries a single copy of a chinook salmon (s) growth hormone (GH) gene spliced to an ocean pout antifreeze promoter (OPA-FPcsGH) co-ligated to a carp beta-actin/lacZ reporter gene construct, integrated into the tilapia genome. Because little is known about the expression sites of transgenes, we have characterised the gene expression patterns of sGH and tilapia (t)GH in transgenic tilapia using a newly established real-time PCR to measure the absolute mRNA amounts of both hormones. The sGH gene, which was expected to be expressed mainly in liver, was also found to be expressed in other organs, such as gills, heart, brain, skeletal muscle, kidney, spleen, intestine and testes. However, in pituitary no sGH mRNA but only tGH mRNA was found. Tilapia GH mRNA in wild-type pituitary amounted to 226 +/- 30 pg/microg total RNA but in transgenics only to 187 +/- 43 pg/microg total RNA. Liver exhibited the highest level of sGH mRNA (8.3 +/- 2.5 pg/microg total RNA) but the extrahepatic sites expressed considerable amounts of sGH mRNA ranging from 4.1 +/- 2.0 pg/microg total RNA in gills to 0.2 +/- 0.08 pg/microg total RNA in kidney. The widespread expression of the sGH gene is assumed to be due to the tissue specificity of the type III AFP gene promoter. It is assumed that our transgenic experiments, which in contrast to some other approaches caused no obvious organ abnormalities, mimick the GH expression during ontogeny. Because sGH mRNA is expressed both in liver and in extrahepatic sites it may not only promote secretion and release of liver-derived (endocrine) IGF-I leading to an overall growth enhancement but also stimulate IGF-I expression within the different organs in a paracrine/autocrine manner and, thus, further promote organ growth.

  1. The Importance of Temperature and Nitrogen Speciation on Bacterial Diversity in Stream Sediments in the McMurdo Dry Valleys (United States)

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


    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.

  2. 人工砂在管桩混凝土中的应用%Application of Artificial Sand in Pipe Pile Concrete

    Institute of Scientific and Technical Information of China (English)



    In this article, the basic parameters of C80F350 artificial sand concrete mixture ratio is determined, and its workability, mechanical properties and durability are tested. Pilot production of artificial sand concrete pipe pile is conducted. Pile bending test and pile dice antipressure and antifreezing test are carried out. The results show that:the mixed sand of machine-made sand and natural sand mixed together in definite proportions can make C80F350 artificial sand concrete which has the same excellent performance with natural san concrete; Compared with natural sand concrete, C80F350 artificial sand concrete higher compressive strength and splitting tensile strength, better frost resistance and permeability resistance, lower chloride ion permeability coefficient and bigger elastic modulus; C80F350 artificial sand concrete is conformed to the existing pipe pile production process, and the pipe pile body bending capacity, dice compressive strength and durability properties can meet the related requirements.%本文确定了C80F350人工砂混凝土配合比的基本参数,测试了其和易性、力学性能及耐久性能,并进行了人工砂混凝土管桩试生产,对桩体进行了抗弯试验,对桩体切块进行了抗压及抗冻试验。结果表明:(1)采用现有机制砂与天然细砂按一定比例混合而成的混合砂可以配制出与天然砂混凝土性能同样优异的C80F350人工砂混凝土;(2)C80F350人工砂混凝土与天然砂混凝土相比具有抗压及劈裂抗拉强度高、抗冻及抗渗性好、氯离子渗透系数低、弹模大等特点;(3)C80F350人工砂混凝土与现有管桩生产工艺相适应,管桩桩体抗弯性能、切块抗压强度及耐久性能均能满足相关要求。

  3. Preparation of 2.5 % chlorpyrifos microspheres suspension concentrate%2.5%毒死蜱微球悬浮剂的制备

    Institute of Scientific and Technical Information of China (English)

    杨石有; 郭瑞峰; 刘德坤; 张翠; 张少飞; 李正杨; 吴刚


    采用流点法对毒死蜱微球悬浮剂的润湿分散剂种类进行了筛选,在所筛选的10种分散剂中,SOPA和N-甲基脂肪酰基牛磺酸盐的流点值较小,分别为0.5032和0.4656.进一步筛选了增稠剂、防冻剂,较优配方:11.2%毒死蜱聚乳酸微球、2.5% SOPA、2.5%N-甲基脂肪酰基牛磺酸盐、3.5%硅酸镁铝、5%乙二醇、0.15%有机硅消泡剂、0.1%苯甲酸钠、水75.05%,制剂的各项质量技术指标基本合格.生测结果表明,2.5%毒死蜱微球悬浮剂对小菜蛾幼虫的毒力略低于48%毒死蜱乳油.%The different wetting dispersants were screened by using pour point method.Among the 10 wetting dispersants,the pour points of SOPA and N-methyl fatty acyltaurine were lower (0.5032 and 0.4656,respectively).Based on the screening of wetting dispersants,thickening agents and anti-freeze agents were obtained.The formulation included 11.2% chlorpyrifos polylactic acid microspheres,2.5% SOPA,2.5% N-methyl fatty acyltaurine,3.5% magnesium aluminum silicate,5% ethylene glycol,0.15% silicone antifoaming agent,0.1% sodium benzoate and 75.05% H2O.The formulation conformed to the requirements for a suspension concentrate in all respects.The LC50 values of 2.5 % chlorpyrifos microspheres suspension concentrate against Plutella xylostella at 48 h was slightly higher than that of 48% chlorpyrifos EC.

  4. Silicon Utilizing Microbial Bioactivities in the Biosphere (United States)

    Sen, M. M.; Das, S.


    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

  5. Insect overwintering in a changing climate. (United States)

    Bale, J S; Hayward, S A L


    Insects are highly successful animals inhabiting marine, freshwater and terrestrial habitats from the equator to the poles. As a group, insects have limited ability to regulate their body temperature and have thus required a range of strategies to support life in thermally stressful environments, including behavioural avoidance through migration and seasonal changes in cold tolerance. With respect to overwintering strategies, insects have traditionally been divided into two main groups: freeze tolerant and freeze avoiding, although this simple classification is underpinned by a complex of interacting processes, i.e. synthesis of ice nucleating agents, cryoprotectants, antifreeze proteins and changes in membrane lipid composition. Also, in temperate and colder climates, the overwintering ability of many species is closely linked to the diapause state, which often increases cold tolerance ahead of temperature-induced seasonal acclimatisation. Importantly, even though most species can invoke one or both of these responses, the majority of insects die from the effects of cold rather than freezing. Most studies on the effects of a changing climate on insects have focused on processes that occur predominantly in summer (development, reproduction) and on changes in distributions rather than winter survival per se. For species that routinely experience cold stress, a general hypothesis would be that predicted temperature increases of 1 degree C to 5 degrees C over the next 50-100 years would increase winter survival in some climatic zones. However, this is unlikely to be a universal effect. Negative impacts may occur if climate warming leads to a reduction or loss of winter snow cover in polar and sub-polar areas, resulting in exposure to more severe air temperatures, increasing frequency of freeze-thaw cycles and risks of ice encasement. Likewise, whilst the dominant diapause-inducing cue (photoperiod) will be unaffected by global climate change, higher temperatures may

  6. Characteristics and origin of organic matter and basal respiration of soils from Majella massif (Central Apennines, Italy) (United States)

    Basili, M.; Cioci, C.; Cocco, S.; Agnelli, A.; di Peco, D.; Ferraris, P.; Corti, G.


    The effects of the global climate change on the soil organic matter (SOM) are still open to debate. Many studies hypothesize an increase of the CO2 fluxes from the soil following the rise of air temperature, especially for the high latitude soils where the low temperatures have a protective effect on the SOM, holding the mineralization reactions back. We studied the feedback between soil and climate change in the Mediterranean environments, on patterned ground soils and soils developed from glacial lacustrine sediments found in the high-elevated areas (2500 m a.s.l.) of Majella massif (Central Apennines, Italy). Here, several profiles were opened and the soil described and sampled according to the recognized horizons. The samples were characterised according to the routine analyses and the SOM extracted according to the International Humic Substances Society protocol. The obtained humic and fulvic acids were characterised for elemental composition and by Fourier-transform infrared (FT-IR) spectroscopy. Further, the basal respiration at 5°C, 20°C and 30°C for 20 days was determined on the samples collected from the superficial horizon of each soil. The extracted humic substances showed a particular composition, being mostly comprised of proteinaceous residues (amides II and III), polysaccarides, and esters and aliphatic compounds. This unusual chemical structure and the paucity of vegetation in the study area could support the hypothesis of a mainly soil animal origin of the SOM, probably due to residues of insects, arachnids and arthropods. In fact, the species belonging to these Orders are abundant in these ecosystems and, further, are often characterised by the presence of compounds, such as glycerine and glycoproteins, in their organic fluids that act as antifreezing systems. The basal respiration experiments indicated that the soil microbial community was active at 5°C, while at 20°C or 30°C rather no respiration occurred; further, after 20 days at both

  7. 冻融环境下引气混凝土的抗钢筋锈蚀能力研究%Study on Ability of Resistance to Steel Corrosion of Air Entraining Concrete Under Freeze-thaw Environment

    Institute of Scientific and Technical Information of China (English)

    马志鸣; 赵铁军; 巴光忠; 管庭


    对带钢筋的普通混凝土及引气混凝土试件进行抗冻融循环试验,在不同冻融损伤程度下对试件进行氯离子侵蚀试验。利用半电池电位法和线性极化法分别测定经过不同冻融循环次数下混凝土试件内部钢筋的电位和腐蚀电流密度,从而定量地确定混凝土内部钢筋的锈蚀情况。研究结果表明:向混凝土内部掺入一定比例引气剂,可以提高混凝土的抗冻性能,从而增强其在腐蚀环境下抗钢筋锈蚀能力,提高了混凝土的耐久性能;对试件进行劈裂试验后,钢筋的实际锈蚀情况与利用由化学方法测定结果一致。%The freeze-thaw cycle tests of the ordinary concrete specimen and the air entraining concrete specimen with steel were carried out ,and the chloride corrosion tests under different freeze-thaw damage degrees were done . The potential values and corrosion current density of steel in concrete specimens were determined under different freeze-thaw cycle times by using half-cell potential method and linear polarization method ,then the steel corrosion condition in concrete was qualitatively determined . The study results show that adding air entraining agent can improve the anti-freeze property of concrete ,promote the ability of resistance to steel corrosion , and prolong the durability of concrete structure .After specimen splitting test ,the actual steel corrosion condition has the same result with the result by chemical approach .

  8. Scavenging of ammonia by raindrops in Saturn's great storm clouds (United States)

    Delitsky, M. L.; Baines, Kevin


    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

  9. 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


    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

  10. 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


    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

  11. 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


    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

  12. Emergence of Habitable Environments in Icy World Interiors (United States)

    Neveu, Marc


    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

  13. 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


    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

  14. Intoxicación por alcoholes Alcohol intoxication

    Directory of Open Access Journals (Sweden)

    J. Roldán


    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.

  15. Preparation of Solvent-free & Water-basedλ-Cyhalothrin Liquid Formulations%无溶剂水基性高效氯氟氰菊酯液体剂型的研制

    Institute of Scientific and Technical Information of China (English)

    华乃震; 罗才宏; 曾鑫年


    [目的]俘油使用较多有机溶剂,而水基性剂型中微乳剂和可溶液剂使用较多极性溶剂作溶剂或助溶剂,在安全和环保性上受到人们质疑.论述水基性无溶剂液体剂型的提出、开发的依据及其优点.这种液体剂型不使用任何(极性和非极性)溶剂和植物油溶剂,研制出一种全新的水基性无溶剂2.5%高效氯氟氰菊酯透明液体剂型.[结果]经研制,其最佳配方:高效氯氟氰菊酯2.5%,乳化剂(烷基酚聚氧乙烯醚,烷基酚聚氧乙烯醚磷酸酯)12%~15%,助表面活性剂(丁醇)5%,防冻剂(丙二醇)2%,水余最.该配方样品为无色透明液体,经冷贮[(0±1)℃,7 d]和热贮[(54±2)℃,14 d]高效氯氟氰菊酯分解率小于2%.[结论]样品经测定各项指标符合有关要求,毒力测定结果与传统微乳剂相同.原料成本仅为同剂量乳油40%、传统微乳剂的72%、生物柴油作溶剂微乳剂的77%.%[Aims]EC uses much solvent, and water-based ME and SL use much solvent & flux (polar solvent), which receives question in the safety and the environmental protection.The water-based solvent-free liquid formulation proposal,development basis and merit were described in the article.This kind of liquid formulation does not use any (polar and nonpolar) solvent and vegetable oil solvent.One kind of brand-new water-based solvent-free λ-cyhalothrin 2.5% transparent liquid formulation was developed.[Results]The optimum ratio was as follow: λ-cyhalothrin 2.5%, emulsifier(alkylphenol ethoxylates, alkylphenol ethoxylates phosphate)12-15%, cosurfactant(butyl alcohol)5%, antifreeze(propylene glycol)2% and water remainder after research.This formula sample was colourless transparent liquid, after stored coldly [(0±1) ℃,7 d]and stored hotly [(54±2) ℃, 14 d], λ-cyhalothrin dissociation rate was less than 2%.[Conclusions]Each target of the sample meets the related requirement after test, and toxicity determination results showed that the

  16. 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


    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

  17. 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


    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。

  18. LabVIEW-operated novel nanoliter osmometer for ice binding protein investigations. (United States)

    Braslavsky, Ido; Drori, Ran


    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

  19. 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


    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

  20. 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)



    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

  1. 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


    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.

  2. 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


    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.

  3. 仪表电伴热在炼油化工企业中的应用%Application of Alectric Heating Instrument in Reifnery and Petrochemical Enterprises

    Institute of Scientific and Technical Information of China (English)



    Heat tracing is regarded as a very effective instruments, piping heat insulation antifreezing measures in various types of chemical enterprises is widely in use for many years, its working principle is produce media heat transfer to the need to be heating instruments, piping, in order to make the instrument work correctly in a cold environment. Electric heat tracing has been fully replaced the steam heating, electric heating heating temperature gradient is small, high power, stable long-term action time and realize the digital, remote and automatic control, equipment easy to install, use the advantages of long service life, no discharge of pollutants, such as many steam heating can not be achieved, has been the key popularized. Electricity companion thermal technology after years of sedimentation and development has by initially constant power type electric with the development of thermal model of semiconductor based automatic temperature control type electric to heat tracing, the control accuracy is higher and higher, application more and more widely. This paper introduces the instrument electric heat tracing in refining and chemical enterprises in the application, hope of refining and chemical enterprises in electric meter with the construction of a thermal have reference value.%我国炼油化工企业目前大多沿用的是传统的蒸汽伴热系统,蒸汽伴热自动化控制程度低,热量转化率低,且与之相配套的配套设备庞大复杂,维修成本高,效率低下。电伴热已经全面代替了蒸汽伴热,电伴热发热温度梯度小,功率大,作用时间稳定长久,而且可以实现数字化、远程化、自动化控制,设备安装容易,使用寿命长,无污染物排放等众多蒸汽伴热无法实现的优点,已被我国重点推广。电伴热技术经过多年的沉淀与发展,已经由起初的恒功率型电伴热发展到新型的以半导体为主的自控温型电伴热,其控制精度越来

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

  5. The Study on Chitosan-Based Aerosol for Cutting Surface of Rubber Trees and Its Antimicrobial and Cold-Prevention Effects%壳聚糖基橡胶树割面喷雾剂及其抗菌防寒效果研究

    Institute of Scientific and Technical Information of China (English)

    杨子明; 彭政; 罗勇悦; 李思东; 李虹; 李普旺


    The objective of the study was to make an efficient aerosol to replace the traditional coating agent for cutting surfaces of rubber trees. A novel chitosan-based aerosol for cutting surface of rubber trees was developed based on the excellent film-formation properties, antimicrobial effects of chitosan and the strong antimicrobial effects of tea tree oil. The film-formation properties of aerosol, the mechanical properties, surface structure, water resistance, air permeability and the antimicrobial effects on phytophthora citrophthora and cold-prevention effect of an aerosol composite membrane were investigated. The experimental results showed that the chitosan-based aerosol for cutting surfaces of rubber trees could obtain excellent film-formation properties. The aerosol composite membrane was insoluble in water, with 5.3 MPa of tensile strength, 24.6% of breaking elongation, 1.99% of transmissivity for CO2, 13.67% of transmissivity for O2, and 99.8% antimicrobial rate toward phytophthora citrophthora. The phenomenon of blasting latex of rubber tree caused by chilling injury was significantly decreased after aerosol treatment, and the dead skin recovery rate of rubber trees was 90.0% . Therefore, It is concluded that the chitosan-based aerosol for cutting surfaces of rubber trees was a user-friendly product with excellent antifreezing and antibacterial effects, which can provide a new strategy for cutting surface protection of rubber tree.%利用壳聚糖良好的成膜防寒作用和茶树油较强的抗菌杀菌作用,研究一种新型的壳聚糖基橡胶树割面喷雾剂以替代传统的橡胶树割面涂封剂.通过对割面喷雾剂的成膜性能、膜的力学性能、表面结构、耐水性、透气性等性能进行了表征,并研究了割面喷雾剂对条溃疡病主要致病菌柑桔褐腐疫霉的抗菌效果及其对橡胶树割面的防寒效果.实验结果表明,壳聚糖基橡胶树割面喷雾剂具有良好的成膜性能,形成的复合

  6. 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


    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

  7. 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


    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.

  8. 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


    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

  9. 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


    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

  10. Value of color Doppler flow imaging on screening and diagnosis of vein thrombosis in perioperative patients with lower extremity fracture%彩色多普勒血流显像筛查下肢骨折围手术期静脉血栓的价值及意义

    Institute of Scientific and Technical Information of China (English)

    徐志强; 刘照宏; 李炎; 方耀忠; 梁峭嵘; 廖荣宗


    tibial vein , 68. 29% (28 /41 ) cases of chronic vein thrombosis happened in calf muscular veniplex , 82. 38% (159/193 ) cases of vein thrombosis caused vein major part or complete blockage , 17. 62% (34/193 ) cases of vein thrombosis caused vein fraction blockage . All patients were treated with anti-freezing , anticoagulant thrombolysis and inferior vena cave filter implantation . Pulmonary thromboembolism happened in 1 patient , who recovered after effective therapy . Conclusion The rate of' vein thrombosis in perioperative lower extremity fracture patients is high . CDFI is a necessary examination in perioperative lower extremity fracture patients , and can provide important referenve for clinical treatment .

  11. 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


    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

  12. Getting Real: A General Chemistry Laboratory Program Focusing on "Real World" Substances (United States)

    Kerber, Robert C.; Akhtar, Mohammad J.


    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

  13. 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


    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.

  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


    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. 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


    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

  16. Cooption of secretory phospholipase (SPLA2) for different aspects of gravity receptor-associated mineralization in vertebrate phylogeny (United States)

    Thalmann, R.; Lu, W.


    mineral modulation not because of its enzymatic activity but to provide a rigid interface conducive to mineral interaction. To provide sufficient matrix protein for in vitro experimentation, we generated recombinant proteins. Circular dichroidism (CD) spectra indicate that the alpha helical structure of the parent SPLA2 is conserved in the SPLAL domains. A precedent of alpha helical structure for provision of a rigid interface was demonstrated to be essential for the activity of the antifreeze protein of the winter flounder. Support for alpha helical structure as signature property of the SPLAL domains of OC90 is the fact that rOC90, when exposed to calcium or carbonate-rich ionic solutions resulted in marked conformational changes, with the largest effects seen by combined application of both ions. The capacity to induce reproducible conformational changes is a testament to the quality and authenticity of rOC90. Alpha helical structure as signature characteristic of OC90 is contrary to the traditional paradigm of beta sheet structure as the essential agent in mineral interaction of highly acidic mollusk shell proteins. Apart from the alpha helical regions of the SPLAL domains, homology-based molecular modeling indicates that most of the linker segment and the terminal extensions consist of unordered structure. The significance of unordered structure in mineral interaction has recently been pointed out by several authors. For instance, the linker segment exhibits a 20 amino residue regions, dominated by hydrogen bonding and charged residues, in other words a hydrophilic segment, suitable for mineral interaction; the same applies to the C-terminal extension. Homology-based molecular models of the SPLAL domains exhibit a spherical surface with a uniform negative electrostatic potential that should be effective in attracting calcium. OC22, the principal soluble aragonitic matrix protein, consists of a single SPLAL domain, with a minor N-linked glycoside. rOC22 in vitro does

  17. The H2O2-H2O Hypothesis: Extremophiles Adapted to Conditions on Mars? (United States)

    Houtkooper, Joop M.; Schulze-Makuch, Dirk


    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