Glass Property Models and Constraints for Estimating the Glass to be Produced at Hanford by Implementing Current Advanced Glass Formulation Efforts

Energy Technology Data Exchange (ETDEWEB)

Vienna, John D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kim, Dong-Sang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Skorski, Daniel C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Matyas, Josef [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2013-07-01

Recent glass formulation and melter testing data have suggested that significant increases in waste loading in HLW and LAW glasses are possible over current system planning estimates. The data (although limited in some cases) were evaluated to determine a set of constraints and models that could be used to estimate the maximum loading of specific waste compositions in glass. It is recommended that these models and constraints be used to estimate the likely HLW and LAW glass volumes that would result if the current glass formulation studies are successfully completed. It is recognized that some of the models are preliminary in nature and will change in the coming years. Plus the models do not currently address the prediction uncertainties that would be needed before they could be used in plant operations. The models and constraints are only meant to give an indication of rough glass volumes and are not intended to be used in plant operation or waste form qualification activities. A current research program is in place to develop the data, models, and uncertainty descriptions for that purpose. A fundamental tenet underlying the research reported in this document is to try to be less conservative than previous studies when developing constraints for estimating the glass to be produced by implementing current advanced glass formulation efforts. The less conservative approach documented herein should allow for the estimate of glass masses that may be realized if the current efforts in advanced glass formulations are completed over the coming years and are as successful as early indications suggest they may be. Because of this approach there is an unquantifiable uncertainty in the ultimate glass volume projections due to model prediction uncertainties that has to be considered along with other system uncertainties such as waste compositions and amounts to be immobilized, split factors between LAW and HLW, etc.

Comparison of a model vapor deposited glass films to equilibrium glass films

Science.gov (United States)

Flenner, Elijah; Berthier, Ludovic; Charbonneau, Patrick; Zamponi, Francesco

Vapor deposition of particles onto a substrate held at around 85% of the glass transition temperature can create glasses with increased density, enthalpy, kinetic stability, and mechanical stability compared to an ordinary glass created by cooling. It is estimated that an ordinary glass would need to age thousands of years to reach the kinetic stability of a vapor deposited glass, and a natural question is how close to the equilibrium is the vapor deposited glass. To understand the process, algorithms akin to vapor deposition are used to create simulated glasses that have a higher kinetic stability than their annealed counterpart, although these glasses may not be well equilibrated either. Here we use novel models optimized for a swap Monte Carlo algorithm in order to create equilibrium glass films and compare their properties with those of glasses obtained from vapor deposition algorithms. This approach allows us to directly assess the non-equilibrium nature of vapor-deposited ultrastable glasses. Simons Collaboration on Cracking the Glass Problem and NSF Grant No. DMR 1608086.

Three-Dimensional Modeling of Glass Lens Molding

DEFF Research Database (Denmark)

Sarhadi, Ali; Hattel, Jesper Henri; Hansen, Hans Nørgaard

2015-01-01

The required accuracy for the final dimensions of the molded lenses in wafer-based precision glass molding as well as the need for elimination of costly experimental trial and error calls for numerical simulations. This study deals with 3D thermo-mechanical modeling of the wafer-based precision...... glass lens molding process. First, a comprehensive 3D thermo-mechanical model of glass is implemented into a FORTRAN user subroutine (UMAT) in the FE program ABAQUS, and the developed FE model is validated with both a well-known sandwich seal test and experimental results of precision molding of several...... glass rings. Afterward, 3D thermo-mechanical modeling of the wafer-based glass lens manufacturing is performed to suggest a proper molding program (i.e., the proper set of process parameters including preset force-time and temperature-time histories) for molding a wafer to a desired dimension...

An empirical modeling tool and glass property database in development of US-DOE radioactive waste glasses

International Nuclear Information System (INIS)

Muller, I.; Gan, H.

1997-01-01

An integrated glass database has been developed at the Vitreous State Laboratory of Catholic University of America. The major objective of this tool was to support glass formulation using the MAWS approach (Minimum Additives Waste Stabilization). An empirical modeling capability, based on the properties of over 1000 glasses in the database, was also developed to help formulate glasses from waste streams under multiple user-imposed constraints. The use of this modeling capability, the performance of resulting models in predicting properties of waste glasses, and the correlation of simple structural theories to glass properties are the subjects of this paper. (authors)

Evaluation of models of waste glass durability

International Nuclear Information System (INIS)

Ellison, A.

1995-01-01

The main variable under the control of the waste glass producer is the composition of the glass; thus a need exists to establish functional relationships between the composition of a waste glass and measures of processability, product consistency, and durability. Many years of research show that the structure and properties of a glass depend on its composition, so it seems reasonable to assume that there also is relationship between the composition of a waste glass and its resistance to attack by an aqueous solution. Several models have been developed to describe this dependence, and an evaluation their predictive capabilities is the subject of this paper. The objective is to determine whether any of these models describe the ''correct'' functional relationship between composition and corrosion rate. A more thorough treatment of the relationships between glass composition and durability has been presented elsewhere, and the reader is encouraged to consult it for a more detailed discussion. The models examined in this study are the free energy of hydration model, developed at the Savannah River Laboratory, the structural bond strength model, developed at the Vitreous State Laboratory at the Catholic University of America, and the Composition Variation Study, developed at Pacific Northwest Laboratory

A structural bond strength model for glass durability

International Nuclear Information System (INIS)

Feng, Xiangdong; Metzger, T.B.

1996-01-01

A glass durability model, structural bond strength (SBS) model was developed to correlate glass durability with its composition. This model assumes that the strengths of the bonds between cations and oxygens and the structural roles of the individual elements in the glass arc the predominant factors controlling the composition dependence of the chemical durability of glasses. The structural roles of oxides in glass are classified as network formers, network breakers, and intermediates. The structural roles of the oxides depend upon glass composition and the redox state of oxides. Al 2 O 3 , ZrO 2 , Fe 2 O 3 , and B 2 O 3 are assigned as network formers only when there are sufficient alkalis to bind with these oxides. CaO can also improve durability by sharing non-bridging oxygen with alkalis, relieving SiO 2 from alkalis. The percolation phenomenon in glass is also taken into account. The SBS model is applied to correlate the 7-day product consistency test durability of 42 low-level waste glasses with their composition with an R 2 of 0.87, which is better than 0.81 obtained with an eight-coefficient empirical first-order mixture model on the same data set

Outlooks for mathematical modelling of the glass melting process

Energy Technology Data Exchange (ETDEWEB)

Waal, H. de [TNO Institute of Applied Physics, Delft (Netherlands)

1997-12-31

Mathematical modelling is nowadays a standard tool for major producers of float glass, T.V. glass and fiberglass. Also for container glass furnaces, glass tank modelling proves to be a valuable method to optimize process conditions. Mathematical modelling is no longer just a way to visualize the flow patterns and to provide data on heat transfer. It can also predict glass quality in relation to process parameters, because all chemical and physical phenomena are included in the latest generation of models, based on experimental and theoretical research on these phenomena.

Ongoing Model Development Analyzing Glass Fracture

DEFF Research Database (Denmark)

Molnar, G.; Bojtar, I.; Nielsen, Jens Henrik

2013-01-01

Present subject deals with an ongoing experimental and numerical analysis of inplane loaded glass plates. The main goal of the investigation is to develop a hybrid – discrete and finite element – model which could follow the fracture process in annealed and in tempered glass. Measurements of the ...... an overview of the structure of the research and a summary of current status archived so far.......Present subject deals with an ongoing experimental and numerical analysis of inplane loaded glass plates. The main goal of the investigation is to develop a hybrid – discrete and finite element – model which could follow the fracture process in annealed and in tempered glass. Measurements...... of the residual stress state before failure and high-speed camera recordings of the failure are being performed in order to verify the numerical model. The primary goal of this research is to follow the overall fracture of a structural element – e.g. beam – loaded inplane. Present paper would like to give...

Modelling of the glass fiber length and the glass fiber length distribution in the compounding of short glass fiber-reinforced thermoplastics

Science.gov (United States)

Kloke, P.; Herken, T.; Schöppner, V.; Rudloff, J.; Kretschmer, K.; Heidemeyer, P.; Bastian, M.; Walther, Dridger, A.

2014-05-01

The use of short glass fiber-reinforced thermoplastics for the production of highly stressed parts in the plastics processing industry has experienced an enormous boom in the last few years. The reasons for this are primarily the improvements to the stiffness and strength properties brought about by fiber reinforcement. These positive characteristics of glass fiber-reinforced polymers are governed predominantly by the mean glass fiber length and the glass fiber length distribution. It is not enough to describe the properties of a plastics component solely as a function of the mean glass fiber length [1]. For this reason, a mathematical-physical model has been developed for describing the glass fiber length distribution in compounding. With this model, it is possible on the one hand to optimize processes for the production of short glass fiber-reinforced thermoplastics, and, on the other, to obtain information on the final distribution, on the basis of which much more detailed statements can be made about the subsequent properties of the molded part. Based on experimental tests, it was shown that this model is able to accurately describe the change in glass fiber length distribution in compounding.

The Mouse Tumor Biology Database: A Comprehensive Resource for Mouse Models of Human Cancer.

Science.gov (United States)

Krupke, Debra M; Begley, Dale A; Sundberg, John P; Richardson, Joel E; Neuhauser, Steven B; Bult, Carol J

2017-11-01

Research using laboratory mice has led to fundamental insights into the molecular genetic processes that govern cancer initiation, progression, and treatment response. Although thousands of scientific articles have been published about mouse models of human cancer, collating information and data for a specific model is hampered by the fact that many authors do not adhere to existing annotation standards when describing models. The interpretation of experimental results in mouse models can also be confounded when researchers do not factor in the effect of genetic background on tumor biology. The Mouse Tumor Biology (MTB) database is an expertly curated, comprehensive compendium of mouse models of human cancer. Through the enforcement of nomenclature and related annotation standards, MTB supports aggregation of data about a cancer model from diverse sources and assessment of how genetic background of a mouse strain influences the biological properties of a specific tumor type and model utility. Cancer Res; 77(21); e67-70. ©2017 AACR . ©2017 American Association for Cancer Research.

START - glass model of PWR

International Nuclear Information System (INIS)

Marn, J.; Ramsak, M.

1998-01-01

Recognizing the importance of nuclear engineering in the area of process engineering the University of Maribor, Faculty of Mechanical Engineering has invested in procuring and erecting glass model of pressurized water reactor. This paper deals with description of the model, its capabilities, and plans for its use within nuclear engineering community of Slovenia. The model, made primarily of glass, serves three purposes: educational, professional development and research. As an example, medium break loss of coolant accident is presented in the paper. Temperatures within primary and secondary side, and pressure on primary side of reactor coolant system are followed. The characteristic points are emphasized, and commented.(author)

Glass viscosity calculation based on a global statistical modelling approach

Energy Technology Data Exchange (ETDEWEB)

Fluegel, Alex

2007-02-01

A global statistical glass viscosity model was developed for predicting the complete viscosity curve, based on more than 2200 composition-property data of silicate glasses from the scientific literature, including soda-lime-silica container and float glasses, TV panel glasses, borosilicate fiber wool and E type glasses, low expansion borosilicate glasses, glasses for nuclear waste vitrification, lead crystal glasses, binary alkali silicates, and various further compositions from over half a century. It is shown that within a measurement series from a specific laboratory the reported viscosity values are often over-estimated at higher temperatures due to alkali and boron oxide evaporation during the measurement and glass preparation, including data by Lakatos et al. (1972) and the recently published High temperature glass melt property database for process modeling by Seward et al. (2005). Similarly, in the glass transition range many experimental data of borosilicate glasses are reported too high due to phase separation effects. The developed global model corrects those errors. The model standard error was 9-17°C, with R^2 = 0.985-0.989. The prediction 95% confidence interval for glass in mass production largely depends on the glass composition of interest, the composition uncertainty, and the viscosity level. New insights in the mixed-alkali effect are provided.

Mouse Models of Gastric Cancer

Science.gov (United States)

Hayakawa, Yoku; Fox, James G.; Gonda, Tamas; Worthley, Daniel L.; Muthupalani, Sureshkumar; Wang, Timothy C.

2013-01-01

Animal models have greatly enriched our understanding of the molecular mechanisms of numerous types of cancers. Gastric cancer is one of the most common cancers worldwide, with a poor prognosis and high incidence of drug-resistance. However, most inbred strains of mice have proven resistant to gastric carcinogenesis. To establish useful models which mimic human gastric cancer phenotypes, investigators have utilized animals infected with Helicobacter species and treated with carcinogens. In addition, by exploiting genetic engineering, a variety of transgenic and knockout mouse models of gastric cancer have emerged, such as INS-GAS mice and TFF1 knockout mice. Investigators have used the combination of carcinogens and gene alteration to accelerate gastric cancer development, but rarely do mouse models show an aggressive and metastatic gastric cancer phenotype that could be relevant to preclinical studies, which may require more specific targeting of gastric progenitor cells. Here, we review current gastric carcinogenesis mouse models and provide our future perspectives on this field. PMID:24216700

Waste glass corrosion modeling: Comparison with experimental results

International Nuclear Information System (INIS)

Bourcier, W.L.

1994-01-01

Models for borosilicate glass dissolution must account for the processes of (1) kinetically-controlled network dissolution, (2) precipitation of secondary phases, (3) ion exchange, (4) rate-limiting diffusive transport of silica through a hydrous surface reaction layer, and (5) specific glass surface interactions with dissolved cations and anions. Current long-term corrosion models for borosilicate glass employ a rate equation consistent with transition state theory embodied in a geochemical reaction-path modeling program that calculates aqueous phase speciation and mineral precipitation/dissolution. These models are currently under development. Future experimental and modeling work to better quantify the rate-controlling processes and validate these models are necessary before the models can be used in repository performance assessment calculations

Overview of chemical modeling of nuclear waste glass dissolution

International Nuclear Information System (INIS)

Bourcier, W.L.

1991-02-01

Glass dissolution takes place through metal leaching and hydration of the glass surface accompanied by development of alternation layers of varying crystallinity. The reaction which controls the long-term glass dissolution rate appears to be surface layer dissolution. This reaction is reversible because the buildup of dissolved species in solution slows the dissolution rate due to a decreased dissolution affinity. Glass dissolution rates are therefore highly dependent on silica concentrations in solution because silica is the major component of the alteration layer. Chemical modeling of glass dissolution using reaction path computer codes has successfully been applied to short term experimental tests and used to predict long-term repository performance. Current problems and limitations of the models include a poorly defined long-term glass dissolution mechanism, the use of model parameters determined from the same experiments that the model is used to predict, and the lack of sufficient validation of key assumptions in the modeling approach. Work is in progress that addresses these issues. 41 refs., 7 figs., 2 tabs

Model based energy benchmarking for glass furnace

International Nuclear Information System (INIS)

Sardeshpande, Vishal; Gaitonde, U.N.; Banerjee, Rangan

2007-01-01

Energy benchmarking of processes is important for setting energy efficiency targets and planning energy management strategies. Most approaches used for energy benchmarking are based on statistical methods by comparing with a sample of existing plants. This paper presents a model based approach for benchmarking of energy intensive industrial processes and illustrates this approach for industrial glass furnaces. A simulation model for a glass furnace is developed using mass and energy balances, and heat loss equations for the different zones and empirical equations based on operating practices. The model is checked with field data from end fired industrial glass furnaces in India. The simulation model enables calculation of the energy performance of a given furnace design. The model results show the potential for improvement and the impact of different operating and design preferences on specific energy consumption. A case study for a 100 TPD end fired furnace is presented. An achievable minimum energy consumption of about 3830 kJ/kg is estimated for this furnace. The useful heat carried by glass is about 53% of the heat supplied by the fuel. Actual furnaces operating at these production scales have a potential for reduction in energy consumption of about 20-25%

Validation Assessment of a Glass-to-Metal Seal Finite-Element Model

Energy Technology Data Exchange (ETDEWEB)

Jamison, Ryan Dale [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Buchheit, Thomas E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Emery, John M [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Romero, Vicente J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stavig, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Newton, Clay S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brown, Arthur [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-10-01

Sealing glasses are ubiquitous in high pressure and temperature engineering applications, such as hermetic feed-through electrical connectors. A common connector technology are glass-to-metal seals where a metal shell compresses a sealing glass to create a hermetic seal. Though finite-element analysis has been used to understand and design glass-to-metal seals for many years, there has been little validation of these models. An indentation technique was employed to measure the residual stress on the surface of a simple glass-to-metal seal. Recently developed rate- dependent material models of both Schott 8061 and 304L VAR stainless steel have been applied to a finite-element model of the simple glass-to-metal seal. Model predictions of residual stress based on the evolution of material models are shown. These model predictions are compared to measured data. Validity of the finite- element predictions is discussed. It will be shown that the finite-element model of the glass-to-metal seal accurately predicts the mean residual stress in the glass near the glass-to-metal interface and is valid for this quantity of interest.

Engineering Glass Passivation Layers -Model Results

Energy Technology Data Exchange (ETDEWEB)

Skorski, Daniel C.; Ryan, Joseph V.; Strachan, Denis M.; Lepry, William C.

2011-08-08

The immobilization of radioactive waste into glass waste forms is a baseline process of nuclear waste management not only in the United States, but worldwide. The rate of radionuclide release from these glasses is a critical measure of the quality of the waste form. Over long-term tests and using extrapolations of ancient analogues, it has been shown that well designed glasses exhibit a dissolution rate that quickly decreases to a slow residual rate for the lifetime of the glass. The mechanistic cause of this decreased corrosion rate is a subject of debate, with one of the major theories suggesting that the decrease is caused by the formation of corrosion products in such a manner as to present a diffusion barrier on the surface of the glass. Although there is much evidence of this type of mechanism, there has been no attempt to engineer the effect to maximize the passivating qualities of the corrosion products. This study represents the first attempt to engineer the creation of passivating phases on the surface of glasses. Our approach utilizes interactions between the dissolving glass and elements from the disposal environment to create impermeable capping layers. By drawing from other corrosion studies in areas where passivation layers have been successfully engineered to protect the bulk material, we present here a report on mineral phases that are likely have a morphological tendency to encrust the surface of the glass. Our modeling has focused on using the AFCI glass system in a carbonate, sulfate, and phosphate rich environment. We evaluate the minerals predicted to form to determine the likelihood of the formation of a protective layer on the surface of the glass. We have also modeled individual ions in solutions vs. pH and the addition of aluminum and silicon. These results allow us to understand the pH and ion concentration dependence of mineral formation. We have determined that iron minerals are likely to form a complete incrustation layer and we plan

Critical properties of a simple spin glass model

International Nuclear Information System (INIS)

Aharony, A.; Imry, Y.

1976-01-01

The Mattis spin glass model is described as following from a particular quenched random solid solution picture, and its zero-field properties are discussed. The random field model is reviewed. The application to the spin glass problem is made and the more general scaling theory presented, and the limitations of the model are discussed

Assessing the Validity of the Simplified Potential Energy Clock Model for Modeling Glass-Ceramics

Energy Technology Data Exchange (ETDEWEB)

Jamison, Ryan Dale [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grillet, Anne M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Stavig, Mark E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Strong, Kevin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Dai, Steve Xunhu [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-10-01

Glass-ceramic seals may be the future of hermetic connectors at Sandia National Laboratories. They have been shown capable of surviving higher temperatures and pressures than amorphous glass seals. More advanced finite-element material models are required to enable model-based design and provide evidence that the hermetic connectors can meet design requirements. Glass-ceramics are composite materials with both crystalline and amorphous phases. The latter gives rise to (non-linearly) viscoelastic behavior. Given their complex microstructures, glass-ceramics may be thermorheologically complex, a behavior outside the scope of currently implemented constitutive models at Sandia. However, it was desired to assess if the Simplified Potential Energy Clock (SPEC) model is capable of capturing the material response. Available data for SL 16.8 glass-ceramic was used to calibrate the SPEC model. Model accuracy was assessed by comparing model predictions with shear moduli temperature dependence and high temperature 3-point bend creep data. It is shown that the model can predict the temperature dependence of the shear moduli and 3- point bend creep data. Analysis of the results is presented. Suggestions for future experiments and model development are presented. Though further calibration is likely necessary, SPEC has been shown capable of modeling glass-ceramic behavior in the glass transition region but requires further analysis below the transition region.

First principles process-product models for vitrification of nuclear waste: Relationship of glass composition to glass viscosity, resistivity, liquidus temperature, and durability

International Nuclear Information System (INIS)

Jantzen, C.M.

1991-01-01

Borosilicate glasses will be used in the USA and in Europe to immobilize radioactive high level liquid wastes (HLLW) for ultimate geologic disposal. Process and product quality models based on glass composition simplify the fabrication of the borosilicate glass while ensuring glass processability and quality. The process model for glass viscosity is based on a relationship between the glass composition and its structural polymerization. The relationship between glass viscosity and electrical resistivity is also shown to relate to glass polymerization. The process model for glass liquidus temperature calculates the solubility of the liquidus phases based on the free energies of formation of the precipitating species. The durability product quality model is based on the calculation of the thermodynamic hydration free energy from the glass composition

Melatonin receptors: latest insights from mouse models

Science.gov (United States)

Tosini, Gianluca; Owino, Sharon; Guillame, Jean-Luc; Jockers, Ralf

2014-01-01

Summary Melatonin, the neuro-hormone synthesized during the night, has recently seen an unexpected extension of its functional implications towards type 2 diabetes development, visual functions, sleep disturbances and depression. Transgenic mouse models were instrumental for the establishment of the link between melatonin and these major human diseases. Most of the actions of melatonin are mediated by two types of G protein-coupled receptors, named MT1 and MT2, which are expressed in many different organs and tissues. Understanding the pharmacology and function of mouse MT1 and MT2 receptors, including MT1/MT2 heteromers, will be of crucial importance to evaluate the relevance of these mouse models for future therapeutic developments. This review will critically discuss these aspects, and give some perspectives including the generation of new mouse models. PMID:24903552

A comparison of the performance of nuclear waste glasses by modeling

International Nuclear Information System (INIS)

Grambow, B.; Strachan, D.M.

1988-01-01

A model selected for the licensing process must be based on a physical and chemical understanding of the glass corrosion mechanism. The purpose of this paper is to show that a dissolution/precipitation model can be used to better understand the effects of various system variables on glass dissolution. The application and validation of this model are also discussed. A dissolution/precipitation model developed appears applicable to experiments with a wide range of solution compositions as well as to more complex systems, such as the bentonite/glass/water system the steel corrosion product/glass/water system, or the dissolution of natural basalt glass in a geologic environment. This model is based on solution chemistry and transition state theory. The theoretical background of this model is discussed elsewhere and is used to describe the dissolution behavior of three nuclear waste glasses. These glasses were selected because they represent a wide range of behavior and, therefore, could be used to illustrate the capabilities of the dissolution/precipitation model. The effects of parameters, such as temperature and starting solution composition, on the dissolution behavior of glass are also discussed. 27 refs., 10 figs., 1 tab

Modeling of Viscosity and Thermal Expansion of Bioactive Glasses

OpenAIRE

Farid, Saad B. H.

2012-01-01

The behaviors of viscosity and thermal expansion for different compositions of bioactive glasses have been studied. The effect of phosphorous pentoxide as a second glass former in addition to silica was investigated. Consequently, the nonlinear behaviors of viscosity and thermal expansion with respect to the oxide composition have been modeled. The modeling uses published data on bioactive glass compositions with viscosity and thermal expansion. -regression optimization technique has been uti...

Models of agglomeration and glass transition

CERN Document Server

Kerner, Richard

2007-01-01

This book is for any physicist interested in new vistas in the domain of non-crystalline condensed matter, aperiodic and quasi-crystalline networks and especially glass physics and chemistry. Students with an elementary background in thermodynamics and statistical physics will find the book accessible. The physics of glasses is extensively covered, focusing on their thermal and mechanical properties, as well as various models leading to the formation of the glassy states of matter from overcooled liquids. The models of agglomeration and growth are also applied to describe the formation of quasicrystals, fullerenes and, in biology, to describe virus assembly pathways.

Rational Design of Mouse Models for Cancer Research

NARCIS (Netherlands)

Landgraf, M.; McGovern, J.A.; Friedl, P.; Hutmacher, D.W.

2018-01-01

The laboratory mouse is widely considered as a valid and affordable model organism to study human disease. Attempts to improve the relevance of murine models for the investigation of human pathologies led to the development of various genetically engineered, xenograft and humanized mouse models.

A new viscosity model for waste glass formulations

International Nuclear Information System (INIS)

Sadler, A.L.K.

1996-01-01

Waste glass formulation requires prediction, with reasonable accuracy, of properties over much wider ranges of composition than are typically encountered in any single industrial application. Melt viscosity is one such property whose behavior must be predicted in formulating new waste glasses. A model was developed for silicate glasses which relates the Arrhenius activation energy for flow to an open-quotes effectiveclose quotes measure of non-bridging oxygen content in the melt, NBO eff . The NBO eff parameter incorporates the differing effects of modifying cations on the depolymerization of the silicate network. The activation energy-composition relationship implied by the model is in accordance with experimental behavior. The model was validated against two different databases, with satisfactory results

Mouse models of Fanconi anemia

International Nuclear Information System (INIS)

Parmar, Kalindi; D'Andrea, Alan; Niedernhofer, Laura J.

2009-01-01

Fanconi anemia is a rare inherited disease characterized by congenital anomalies, growth retardation, aplastic anemia and an increased risk of acute myeloid leukemia and squamous cell carcinomas. The disease is caused by mutation in genes encoding proteins required for the Fanconi anemia pathway, a response mechanism to replicative stress, including that caused by genotoxins that cause DNA interstrand crosslinks. Defects in the Fanconi anemia pathway lead to genomic instability and apoptosis of proliferating cells. To date, 13 complementation groups of Fanconi anemia were identified. Five of these genes have been deleted or mutated in the mouse, as well as a sixth key regulatory gene, to create mouse models of Fanconi anemia. This review summarizes the phenotype of each of the Fanconi anemia mouse models and highlights how genetic and interventional studies using the strains have yielded novel insight into therapeutic strategies for Fanconi anemia and into how the Fanconi anemia pathway protects against genomic instability.

Mouse models of Fanconi anemia

Energy Technology Data Exchange (ETDEWEB)

Parmar, Kalindi; D' Andrea, Alan [Department of Radiation Oncology, Dana-Farber Cancer Institute, Harvard Medical School, 44 Binney Street, Boston, MA 02115 (United States); Niedernhofer, Laura J., E-mail: niedernhoferl@upmc.edu [Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine and Cancer Institute, 5117 Centre Avenue, Hillman Cancer Center, Research Pavilion 2.6, Pittsburgh, PA 15213-1863 (United States)

2009-07-31

Fanconi anemia is a rare inherited disease characterized by congenital anomalies, growth retardation, aplastic anemia and an increased risk of acute myeloid leukemia and squamous cell carcinomas. The disease is caused by mutation in genes encoding proteins required for the Fanconi anemia pathway, a response mechanism to replicative stress, including that caused by genotoxins that cause DNA interstrand crosslinks. Defects in the Fanconi anemia pathway lead to genomic instability and apoptosis of proliferating cells. To date, 13 complementation groups of Fanconi anemia were identified. Five of these genes have been deleted or mutated in the mouse, as well as a sixth key regulatory gene, to create mouse models of Fanconi anemia. This review summarizes the phenotype of each of the Fanconi anemia mouse models and highlights how genetic and interventional studies using the strains have yielded novel insight into therapeutic strategies for Fanconi anemia and into how the Fanconi anemia pathway protects against genomic instability.

Affinity functions for modeling glass dissolution rates

Energy Technology Data Exchange (ETDEWEB)

Bourcier, W.L. [Lawrence Livermore National Lab., CA (United States)

1997-07-01

Glass dissolution rates decrease dramatically as glass approach ''saturation'' with respect to the leachate solution. Most repository sites are chosen where water fluxes are minimal, and therefore the waste glass is most likely to dissolve under conditions close to ''saturation''. The key term in the rate expression used to predict glass dissolution rates close to ''saturation'' is the affinity term, which accounts for saturation effects on dissolution rates. Interpretations of recent experimental data on the dissolution behaviour of silicate glasses and silicate minerals indicate the following: 1) simple affinity control does not explain the observed dissolution rate for silicate minerals or glasses; 2) dissolution rates can be significantly modified by dissolved cations even under conditions far from saturation where the affinity term is near unity; 3) the effects of dissolved species such as Al and Si on the dissolution rate vary with pH, temperature, and saturation state; and 4) as temperature is increased, the effect of both pH and temperature on glass and mineral dissolution rates decrease, which strongly suggests a switch in rate control from surface reaction-based to diffusion control. Borosilicate glass dissolution models need to be upgraded to account for these recent experimental observations. (A.C.)

A comparison of the performance of nuclear waste glasses by modeling

International Nuclear Information System (INIS)

Grambow, B.; Strachan, D.M.

1988-12-01

Through a combination of data collection and computer modeling, the dissolution mechanism of nuclear waste glasses has been investigated and more clearly defined. Glass dissolution can be described as a dissolution/precipitation process in which glass dissolves in aqueous solution and solids precipitate as the solubility products are exceeded. The dissolution process is controlled by activity of the rate-limiting specie H 4 SiO 4 . As a concentration of H 4 SiO 4 increases, the rate of dissolution decreases until a final reaction rate is reached. Between the forward reaction rate (early time) and final reaction rate (very long time), glasses may exhibit an intermediate root time dependence caused by a transport resistance for the diffusion of H 4 SiO 4 within the gel layer on the glass surface. In this report, three glasses are studied: JSS-A, PNL 76-68, and SRL-131. Data from static and dynamic leach tests are assembled, plotted, and successfully modeled. The kinetic parameters for these glasses are reported. With four parameters derived from experiments for each glass, the model can be used to calculate the effects of changes in the initial composition of the water contacting the glass. The effects of convective flow can also be modeled. Furthermore, glasses of different compositions can be readily compared. 49 refs., 27 figs., 5 tabs

Metallic glasses: structural models

International Nuclear Information System (INIS)

Nassif, E.

1984-01-01

The aim of this work is to give a summary of the attempts made up to the present in order to discribe by structural models the atomic arrangement in metallic glasses, showing also why the structure factors and atomic distribution functions cannot be always experimentally determined with a reasonable accuracy. (M.W.O.) [pt

Utilizing the non-bridge oxygen model to predict the glass viscosity

International Nuclear Information System (INIS)

Choi, Kwansik; Sheng, Jiawei; Maeng, Sung Jun; Song, Myung Jae

1998-01-01

Viscosity is the most important process property of waste glass. Viscosity measurement is difficult and costs much. Non-bridging Oxygen (NBO) model which relates glass composition to viscosity had been developed for high level waste at the Savannah River Site (SRS). This research utilized this NBO model to predict the viscosity of KEPRI's 55 glasses. It was found that there was a linear relationship between the measured viscosity and the predicted viscosity. The NBO model could be used to predict glass viscosity in glass formulation development. However the precision of predicted viscosity is out of satisfaction because the composition ranges are very different between the SRS and KEPRI glasses. The modification of NBO calculation, which included modification of alkaline earth elements and TiO 2 , could not strikingly improve the precision of predicted values

Drilling in tempered glass – modelling and experiments

DEFF Research Database (Denmark)

Nielsen, Jens Henrik

The present paper reports experimentally and numerically obtained results for the process of drilling in tempered glass. The experimental results are drilling depths on the edge in 19mm tempered glass with a known residual stress state measured by a scattered light polariscope. The experiments have...... been modelled using a state-of-the-art model and compared with satisfying result to the performed experiments. The numerical model has been used for a parametric study, investigating the redistribution of residual stresses during the process of drilling. This is done for investigating the possibility...... of applying forces in such holes and thereby being able to mechanically assemble tempered glass without the need of drilling holes before the tempering process. The paper is the result of currently ongoing research and the results should be treated as so....

The Mouse Genome Database (MGD): facilitating mouse as a model for human biology and disease.

Science.gov (United States)

Eppig, Janan T; Blake, Judith A; Bult, Carol J; Kadin, James A; Richardson, Joel E

2015-01-01

The Mouse Genome Database (MGD, http://www.informatics.jax.org) serves the international biomedical research community as the central resource for integrated genomic, genetic and biological data on the laboratory mouse. To facilitate use of mouse as a model in translational studies, MGD maintains a core of high-quality curated data and integrates experimentally and computationally generated data sets. MGD maintains a unified catalog of genes and genome features, including functional RNAs, QTL and phenotypic loci. MGD curates and provides functional and phenotype annotations for mouse genes using the Gene Ontology and Mammalian Phenotype Ontology. MGD integrates phenotype data and associates mouse genotypes to human diseases, providing critical mouse-human relationships and access to repositories holding mouse models. MGD is the authoritative source of nomenclature for genes, genome features, alleles and strains following guidelines of the International Committee on Standardized Genetic Nomenclature for Mice. A new addition to MGD, the Human-Mouse: Disease Connection, allows users to explore gene-phenotype-disease relationships between human and mouse. MGD has also updated search paradigms for phenotypic allele attributes, incorporated incidental mutation data, added a module for display and exploration of genes and microRNA interactions and adopted the JBrowse genome browser. MGD resources are freely available to the scientific community. © The Author(s) 2014. Published by Oxford University Press on behalf of Nucleic Acids Research.

Numerical modelling of glass dissolution: gel layer morphology

Energy Technology Data Exchange (ETDEWEB)

Devreux, F. E-mail: fd@pmc.polytechnique.fr; Barboux, P

2001-09-01

Numerical simulations of glass dissolution are presented. The glass is modelized as a random binary mixture composed of two species representing silica and soluble oxides, such as boron and alkali oxides. The soluble species are dissolved immediately when they are in contact with the solution. For the species which represents silica, one introduces dissolution and condensation probabilities. It is shown that the morphology and the thickness of the surface hydration layer (the gel) are highly dependent on the dissolution model, especially on the parameter which controls the surface tension. Simulations with different glass surface area to solution volume ratio (S/V) show that this experimental parameter has important effects on both the shrinkage and the gel layer thickness.

The wobbler mouse, an ALS animal model

DEFF Research Database (Denmark)

Moser, Jakob Maximilian; Bigini, Paolo; Schmitt-John, Thomas

2013-01-01

This review article is focused on the research progress made utilizing the wobbler mouse as animal model for human motor neuron diseases, especially the amyotrophic lateral sclerosis (ALS). The wobbler mouse develops progressive degeneration of upper and lower motor neurons and shows striking...

A Kondo cluster-glass model for spin glass Cerium alloys

International Nuclear Information System (INIS)

Zimmer, F M; Magalhaes, S G; Coqblin, B

2011-01-01

There are clear indications that the presence of disorder in Ce alloys, such as Ce(Ni,Cu) or Ce(Pd,Rh), is responsible for the existence of a cluster spin glass state which changes continuously into inhomogeneous ferromagnetism at low temperatures. We present a study of the competition between magnetism and Kondo effect in a cluster-glass model composed by a random inter-cluster interaction term and an intra-cluster one, which contains an intra-site Kondo interaction J k and an inter-site ferromagnetic one J 0 . The random interaction is given by the van Hemmen type of randomness which allows to solve the problem without the use of the replica method. The inter-cluster term is solved within the cluster mean-field theory and the remaining intra-cluster interactions can be treated by exact diagonalization. Results show the behavior of the cluster glass order parameter and the Kondo correlation function for several sizes of the clusters, J k , J 0 and values of the ferromagnetic inter-cluster average interaction I 0 . Particularly, for small J k , the magnetic solution is strongly dependent on I 0 and J 0 and a Kondo cluster-glass or a mixed phase can be obtained, while, for large J k , the Kondo effect is still dominant, both in good agreement with experiment in Ce(Ni,Cu) or Ce(Pd,Rh) alloys.

Thermodynamic model of natural, medieval and nuclear waste glass durability

International Nuclear Information System (INIS)

Jantzen, C.M.; Plodinec, M.J.

1983-01-01

A thermodynamic model of glass durability based on hydration of structural units has been applied to natural glass, medieval window glasses, and glasses containing nuclear waste. The relative durability predicted from the calculated thermodynamics correlates directly with the experimentally observed release of structural silicon in the leaching solution in short-term laboratory tests. By choosing natural glasses and ancient glasses whose long-term performance is known, and which bracket the durability of waste glasses, the long-term stability of nuclear waste glasses can be interpolated among these materials. The current Savannah River defense waste glass formulation is as durable as natural basalt from the Hanford Reservation (10 6 years old). The thermodynamic hydration energy is shown to be related to the bond energetics of the glass. 69 references, 2 figures, 1 table

Glass operational file. Operational models and integration calculations

International Nuclear Information System (INIS)

Ribet, I.

2004-01-01

This document presents the operational choices of dominating phenomena, hypotheses, equations and numerical data of the parameters used in the two operational models elaborated for the calculation of the glass source terms with respect to the waste packages considered: existing packages (R7T7, AVM and CEA glasses) and future ones (UOX2, UOX3, UMo, others). The overall operational choices are justified and demonstrated and a critical analysis of the approach is systematically proposed. The use of the operational model (OPM) V 0 → V r , realistic, conservative and robust, is recommended for glasses with a high thermal and radioactive load, which represent the main part of the vitrified wastes. The OPM V 0 S, much more overestimating but faster to parameterize, can be used for the long-term behaviour forecasting of glasses with low thermal and radioactive load, considering today's lack of knowledge for the parameterization of a V 0 → V r type OPM. Efficiency estimations have been made for R7T7 glasses (OPM V 0 → V r ) and AVM glasses (OPM V 0 S), which correspond to more than 99.9% of the vitrified waste packages activity. The very contrasted results obtained, illustrate the importance of the choice of operational models: in conditions representative of a geologic disposal, the estimation of R7T7-type package lifetime exceeds several hundred thousands years. Even if the estimated lifetime of AVM packages is much shorter (because of the overestimating character of the OPM V 0 S), the release potential radiotoxicity is of the same order as the one of R7T7 packages. (J.S.)

Mouse Models of the Skin: Models to Define Mechanisms of Skin Carcinogenesis

International Nuclear Information System (INIS)

Wheeler, D. L.; Verma, A. K.; Denning, M. F.

2013-01-01

The multistep model of mouse skin carcinogenesis has facilitated identification of irreversible genetic events of initiation and progression, and epigenetic events of tumor promotion. Mouse skin tumor initiation can be accomplished by a single exposure to a sufficiently small dose of a carcinogen, and this step is rapid and irreversible. However, promotion of skin tumor formation requires a repeated and prolonged exposure to a promoter, and that tumor promotion is reversible. Investigations focused on the mechanisms of mouse carcinogenesis have resulted in the identifications of potential molecular targets of cancer induction and progression useful in planning strategies for human cancer prevention trials. This special issue contains eight papers that focus on mouse models used to study individual proteins expressed in the mouse skin and the role they play in differentiation, tissue homeostasis, skin carcinogenesis, and chemo prevention of skin cancer.

A Humanized Mouse Model Generated Using Surplus Neonatal Tissue

Directory of Open Access Journals (Sweden)

Matthew E. Brown

2018-04-01

Full Text Available Summary: Here, we describe the NeoThy humanized mouse model created using non-fetal human tissue sources, cryopreserved neonatal thymus and umbilical cord blood hematopoietic stem cells (HSCs. Conventional humanized mouse models are made by engrafting human fetal thymus and HSCs into immunocompromised mice. These mice harbor functional human T cells that have matured in the presence of human self-peptides and human leukocyte antigen molecules. Neonatal thymus tissue is more abundant and developmentally mature and allows for creation of up to ∼50-fold more mice per donor compared with fetal tissue models. The NeoThy has equivalent frequencies of engrafted human immune cells compared with fetal tissue humanized mice and exhibits T cell function in assays of ex vivo cell proliferation, interferon γ secretion, and in vivo graft infiltration. The NeoThy model may provide significant advantages for induced pluripotent stem cell immunogenicity studies, while bypassing the requirement for fetal tissue. : Corresponding author William Burlingham and colleagues created a humanized mouse model called the NeoThy. The NeoThy uses human neonatal, rather than fetal, tissue sources for generating a human immune system within immunocompromised mouse hosts. NeoThy mice are an attractive alternative to conventional humanized mouse models, as they enable robust and reproducible iPSC immunogenicity experiments in vivo. Keywords: NeoThy, humanized mouse, iPSC, PSC, immunogenicity, transplantation, immunology, hematopoietic stem cells, induced pluripotent stem cells, thymus

Enhancement of the glass corrosion in the presence of clay minerals: testing experimental results with an integrated glass dissolution model

International Nuclear Information System (INIS)

Godon, N.; Vernaz, E.Y.

1992-01-01

Recent glass dissolution experiments, conducted at 90 deg C in the presence of potential backfill materials, indicate remarkably faster glass corrosion in the presence of clay, compared to tests where the glass is leached either alone or with alternative backfill materials. This effect correlates with the clay content in the backfill, and may be attributed to the removal of silica from solution. Scorpion, or dissolution with reprecipitation of a silica-rich clay, have been proposed as possible mechanisms for the silica consumption. The results of some experiments have been tested against a glass dissolution model, in which a widely used kinetic equation for glass corrosion is coupled with diffusive silica transport through a single porosity, linearly sorbing medium, which represents the backfilling. Because the glass corrosion rates imposed by the kinetic equation are inversely proportional to the silicic acid concentration of the leachant contacting the glass, the model predicts enhanced glass dissolution if silica is sorbed by the porous medium. The experimental data proved to be consistent with the predicted enhancement of the glass dissolution. Moreover, the model-estimated distribution coefficients for silica sorption (K d ) fall within the range of values extracted from available literature data, thus supporting the hypothesis that the observed high corrosion rates are due to sorption of silica on the clay mineral surfaces. (author)

Thermochemical modeling of nuclear waste glass

International Nuclear Information System (INIS)

Spear, K.E.; Besmann, T.M.; Beahm, E.C.

1998-06-01

The development of assessed and consistent phase equilibria and thermodynamic data for major glass constituents used to incorporate high-level nuclear waste is discussed in this paper. The initial research has included the binary Na 2 O-SiO 2 , Na 2 O-Al 2 O 3 , and SiO 2 -Al 2 O 3 systems. The nuclear waste glass is assumed to be a supercooled liquid containing the constituents in the glass at temperatures of interest for nuclear waste storage. Thermodynamic data for the liquid solutions were derived from mathematical comparisons of phase diagram information and the thermodynamic data available for crystalline solid phases. An associate model is used to describe the liquid solution phases. Utilizing phase diagram information provides very stringent limits on the relative thermodynamic stabilities of all phases which exist in a given system

Mean field models for spin glasses

CERN Document Server

Talagrand, Michel

2011-01-01

This is a new, completely revised, updated and enlarged edition of the author's Ergebnisse vol. 46: "Spin Glasses: A Challenge for Mathematicians". This new edition will appear in two volumes, the present first volume presents the basic results and methods, the second volume is expected to appear in 2011. In the eighties, a group of theoretical physicists introduced several models for certain disordered systems, called "spin glasses". These models are simple and rather canonical random structures, of considerable interest for several branches of science (statistical physics, neural networks and computer science). The physicists studied them by non-rigorous methods and predicted spectacular behaviors. This book introduces in a rigorous manner this exciting new area to the mathematically minded reader. It requires no knowledge whatsoever of any physics. The first volume of this new and completely rewritten edition presents six fundamental models and the basic techniques to study them.

Behavioral phenotypes of genetic mouse models of autism.

Science.gov (United States)

Kazdoba, T M; Leach, P T; Crawley, J N

2016-01-01

More than a hundred de novo single gene mutations and copy-number variants have been implicated in autism, each occurring in a small subset of cases. Mutant mouse models with syntenic mutations offer research tools to gain an understanding of the role of each gene in modulating biological and behavioral phenotypes relevant to autism. Knockout, knockin and transgenic mice incorporating risk gene mutations detected in autism spectrum disorder and comorbid neurodevelopmental disorders are now widely available. At present, autism spectrum disorder is diagnosed solely by behavioral criteria. We developed a constellation of mouse behavioral assays designed to maximize face validity to the types of social deficits and repetitive behaviors that are central to an autism diagnosis. Mouse behavioral assays for associated symptoms of autism, which include cognitive inflexibility, anxiety, hyperactivity, and unusual reactivity to sensory stimuli, are frequently included in the phenotypic analyses. Over the past 10 years, we and many other laboratories around the world have employed these and additional behavioral tests to phenotype a large number of mutant mouse models of autism. In this review, we highlight mouse models with mutations in genes that have been identified as risk genes for autism, which work through synaptic mechanisms and through the mTOR signaling pathway. Robust, replicated autism-relevant behavioral outcomes in a genetic mouse model lend credence to a causal role for specific gene contributions and downstream biological mechanisms in the etiology of autism. © 2015 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

A model for radiative cooling of a semitransparent molten glass jet

International Nuclear Information System (INIS)

Song, M.; Ball, K.S.; Bergman, T.L.

1998-01-01

Transfer of molten glass from location to location typically involves a pouring process, during which a stream of glass is driven by gravity and cooled by combined convective and radiative heat transfer. This study of the thermal and fluid mechanics aspects of glass pouring is motivated by the glass casting of vitrified, surplus weapons-grade plutonium. Here, a mathematical model for the radiative cooling of a semitransparent molten glass jet with temperature-dependent viscosity has been developed and is implemented numerically. The axial velocity and jet diameter variations along the length of the jet, the axial bulk mean temperature distributions, and the centerline-to-surface glass temperature distributions are determined for different processing conditions. Comparisons are also made between the semitransparent predictions, which are based on a spectral discrete ordinates model, and predictions for an opaque medium

Modelling the crystallisation of alkaline earth boroaluminosilicate glass ceramics

DEFF Research Database (Denmark)

Svenson, Mouritz Nolsøe; Agersted, Karsten; Holm, Paul Martin

2014-01-01

To investigate the potential use of a thermochemical software package (FactSage 6.2), in the design of alkaline earth boroaluminosilicate glass ceramics, experimental and modelled results on four glass ceramics were compared. Initially large discrepancies were found. These are described and related...

Exploration and Modeling of Structural changes in Waste Glass Under Corrosion

Energy Technology Data Exchange (ETDEWEB)

Pantano, Carlos; Ryan, Joseph; Strachan, Denis

2013-11-10

Vitrification is currently the world-wide treatment of choice for the disposition of high-level nuclear wastes. In glasses, radionuclides are atomistically bonded into the solid, resulting in a highly durable product, with borosilicate glasses exhibiting particularly excellent durability in water. Considering that waste glass is designed to retain the radionuclides within the waste form for long periods, it is important to understand the long-term stability of these materials when they react in the environment, especially in the presence of water. Based on a number of previous studies, there is general consensus regarding the mechanisms controlling the initial rate of nuclear waste glass dissolution. Agreement regarding the cause of the observed decrease in dissolution rate at extended times, however, has been elusive. Two general models have been proposed to explain this behavior, and it has been concluded that both concepts are valid and must be taken into account when considering the decrease in dissolution rate. Furthermore, other processes such as water diffusion, ion exchange, and precipitation of mineral phases onto the glass surface may occur in parallel with dissolution of the glass and can influence long-term performance. Our proposed research will address these issues through a combination of aqueous-phase dissolution/reaction experiments and probing of the resulting surface layers with state-of-the-art analytical methods. These methods include solid-state nuclear magnetic resonance (SSNMR) and time-of-flight secondary ion mass spectrometry (TOF-SIMS). The resulting datasets will then be coupled with computational chemistry and reaction-rate modeling to address the most persistent uncertainties in the understanding of glass corrosion, which indeed have limited the performance of the best corrosion models to date. With an improved understanding of corrosion mechanisms, models can be developed and improved that, while still conservative, take advantage of

A model for phosphate glass topology considering the modifying ion sub-network

DEFF Research Database (Denmark)

Hermansen, Christian; Mauro, J.C.; Yue, Yuanzheng

2014-01-01

In the present paper we establish a temperature dependent constraint model of alkali phosphate glasses considering the structural and topological role of the modifying ion sub-network constituted by alkali ions and their non-bonding oxygen coordination spheres. The model is consistent with availa......In the present paper we establish a temperature dependent constraint model of alkali phosphate glasses considering the structural and topological role of the modifying ion sub-network constituted by alkali ions and their non-bonding oxygen coordination spheres. The model is consistent...... with available structural data by NMR and molecular dynamics simulation and dynamic data such glass transition temperature (Tg) and liquid fragility (m). Alkali phosphate glasses are exemplary systems for developing constraint model since the modifying cation network plays an important role besides the primary...... phosphate network. The proposed topological model predicts the changing trend of the Tg and m with increasing alkali oxide content for alkali phosphate glasses, including an anomalous minimum at around 20 mol% alkali oxide content. We find that the minimum in Tg and m is caused by increased connectivity...

Mouse Model of Burn Wound and Infection

DEFF Research Database (Denmark)

Calum, Henrik; Høiby, Niels; Moser, Claus

2017-01-01

The immunosuppression induced by thermal injury renders the burned victim susceptible to infection. A mouse model was developed to examine the immunosuppression, which was possible to induce even at a minor thermal insult of 6% total body surface area. After induction of the burn (48 hr) a depres......The immunosuppression induced by thermal injury renders the burned victim susceptible to infection. A mouse model was developed to examine the immunosuppression, which was possible to induce even at a minor thermal insult of 6% total body surface area. After induction of the burn (48 hr...

Development of Models to Predict the Redox State of Nuclear Waste Containment Glass

Energy Technology Data Exchange (ETDEWEB)

Pinet, O.; Guirat, R.; Advocat, T. [Commissariat a l' Energie Atomique (CEA), Departement de Traitement et de Conditionnement des Dechets, Marcoule, BP 71171, 30207 Bagnols-sur-Ceze Cedex (France); Phalippou, J. [Universite de Montpellier II, Laboratoire des Colloides, Verres et Nanomateriaux, 34095 Montpellier Cedex 5 (France)

2008-07-01

Vitrification is one of the recommended immobilization routes for nuclear waste, and is currently implemented at industrial scale in several countries, notably for high-level waste. To optimize nuclear waste vitrification, research is conducted to specify suitable glass formulations and develop more effective processes. This research is based not only on experiments at laboratory or technological scale, but also on computer models. Vitrified nuclear waste often contains several multi-valent species whose oxidation state can impact the properties of the melt and of the final glass; these include iron, cerium, ruthenium, manganese, chromium and nickel. Cea is therefore also developing models to predict the final glass redox state. Given the raw materials and production conditions, the model predicts the oxygen fugacity at equilibrium in the melt. It can also estimate the ratios between the oxidation states of the multi-valent species contained in the molten glass. The oxidizing or reductive nature of the atmosphere above the glass melt is also taken into account. Unlike the models used in the conventional glass industry based on empirical methods with a limited range of application, the models proposed are based on the thermodynamic properties of the redox species contained in the waste vitrification feed stream. The thermodynamic data on which the model is based concern the relationship between the glass redox state and the oxygen fugacity in the molten glass. The model predictions were compared with oxygen fugacity measurements for some fifty glasses. The experiments carried out at laboratory and industrial scale with a cold crucible melter. The oxygen fugacity of the glass samples was measured by electrochemical methods and compared with the predicted value. The differences between the predicted and measured oxygen fugacity values were generally less than 0.5 Log unit. (authors)

Nano-Continuum Modeling of a Nuclear Glass Specimen Altered for 25 Years

Energy Technology Data Exchange (ETDEWEB)

Steefel, Carl

2014-01-06

The purpose of this contribution is to report on preliminary nano-continuum scale modeling of nuclear waste glass corrosion. The focus of the modeling is an experiment involving a French glass SON68 specimen leached for 25 years in a granitic environment. In this report, we focus on capturing the nano-scale concentration profiles. We use a high resolution continuum model with a constant grid spacing of 1 nanometer to investigate the glass corrosion mechanisms.

Incorporating Cold Cap Behavior in a Joule-heated Waste Glass Melter Model

Energy Technology Data Exchange (ETDEWEB)

Varija Agarwal; Donna Post Guillen

2013-08-01

In this paper, an overview of Joule-heated waste glass melters used in the vitrification of high level waste (HLW) is presented, with a focus on the cold cap region. This region, in which feed-to-glass conversion reactions occur, is critical in determining the melting properties of any given glass melter. An existing 1D computer model of the cold cap, implemented in MATLAB, is described in detail. This model is a standalone model that calculates cold cap properties based on boundary conditions at the top and bottom of the cold cap. Efforts to couple this cold cap model with a 3D STAR-CCM+ model of a Joule-heated melter are then described. The coupling is being implemented in ModelCenter, a software integration tool. The ultimate goal of this model is to guide the specification of melter parameters that optimize glass quality and production rate.

Stereodynamic insight into the thermal history effects on poly(vinyl chloride) calorimetric sub-glass and glass transitions as a fragile glass model.

Science.gov (United States)

Pin, Jean-Mathieu; Behazin, Ehsan; Misra, Manjusri; Mohanty, Amar

2018-05-02

The dynamic thermal history impact of poly(vinyl chloride) (PVC) has been explored for a wide range of pre-cooling rates, from 1 to 30 °C min-1. A first macroscopic insight into the dynamic thermal history influence has been highlighted through a decrease in the apparent activation energy (Eapp) in the first stage of the glass transition. The overall glass transition Eapp surface was successfully modeled in a polynomial fashion regarding the pre-cooling range. Raman scattering was used to associate the Eapp variations along the glass transition conversion with the stereochemistry evolution during the polymeric relaxation. Herein, the selection of atactic PVC as the polymer model permits us to monitor the glassy polymer segment stereodynamics during the heating ramp through the C-Cl stretching. The intermolecular H-Cl dipole interactions, as well as intramolecular conformational reorganizations among syndiotactic, isotactic and heterotactic polymer sequences, have been associated with non-cooperative and cooperative motions, i.e. the β- and α-process, respectively. The fruitful comparison of the two extreme values of the pre-cooling rates permits us to propose a thermokinetic scenario that explains the occurrence, intensity, and inter-dependence of β- and α-processes in the glassy state and during the glass transition. This scenario could potentially be generalized to all the other polymeric glass-formers.

Dissolution model for a glass having an adherent insoluble surface layer

International Nuclear Information System (INIS)

Harvey, K.B.; Larocque, C.A.B.

1990-01-01

Waste form glasses that contain substantial quantities of iron, manganese, and aluminum oxides, such as the Savannah River SRL TDS-131 glass, form a thick, hydrated surface layer when placed in contact with water. The dissolution of such a glass has been modeled with the Savannah River Model. The authors showed previously that the equations of the Savannah River Model could be fitted to published experimental data if a time-dependent diffusion coefficient was assumed for species of diffusing through the surface layer. The Savannah River Model assumes that all of the material dissolved from the glass enters solution, whereas it was observed that substantial quantities of material were retained in the surface layer. An alternative model, presented contains a mass balance equation that allows material either to enter solution or to be retained in the surface layer. It is shown that the equations derived using this model can be fitted to the published experimental data assuming a constant diffusion coefficient for species diffusing through the surface layer

Understanding the structural drivers governing glass-water interactions in borosilicate based model bioactive glasses.

Science.gov (United States)

Stone-Weiss, Nicholas; Pierce, Eric M; Youngman, Randall E; Gulbiten, Ozgur; Smith, Nicholas J; Du, Jincheng; Goel, Ashutosh

2018-01-01

borosilicate based model melt-quenched bioactive glass system has been studied to depict the impact of thermal history on its molecular structure and dissolution behavior in water. It has been shown that the methodology of quenching of the glass melt impacts the dissolution rate of the studied glasses by 1.5×-3× depending on the changes induced in their molecular structure due to variation in thermal history. Further, a recommendation has been made to study dissolution behavior of bioactive glasses using surface area of the sample - to - volume of solution (SA/V) approach instead of the currently followed mass of sample - to - volume of solution approach. The structural and chemical dissolution data obtained from bioactive glasses following the approach presented in this paper can be used to develop the structural descriptors and potential energy functions over a broad range of bioactive glass compositions. Realizing the goal of designing third generation bioactive glasses requires a thorough understanding of the complex sequence of reactions that control their rate of degradation (in physiological fluids) and the structural drivers that control them. In this article, we have highlighted some major experimental challenges and choices that need to be carefully navigated in order to unearth the mechanisms governing the chemical dissolution behavior of borosilicate based bioactive glasses. The proposed experimental approach allows us to gain a new level of conceptual understanding about the composition-structure-property relationships in these glass systems, which can be applied to attain a significant leap in designing borosilicate based bioactive glasses with controlled dissolution rates tailored for specific patient and disease states. Copyright © 2017 Acta Materialia Inc. All rights reserved.

A Mouse Model of Chronic West Nile Virus Disease.

Directory of Open Access Journals (Sweden)

Jessica B Graham

2016-11-01

Full Text Available Infection with West Nile virus (WNV leads to a range of disease outcomes, including chronic infection, though lack of a robust mouse model of chronic WNV infection has precluded identification of the immune events contributing to persistent infection. Using the Collaborative Cross, a population of recombinant inbred mouse strains with high levels of standing genetic variation, we have identified a mouse model of persistent WNV disease, with persistence of viral loads within the brain. Compared to lines exhibiting no disease or marked disease, the F1 cross CC(032x013F1 displays a strong immunoregulatory signature upon infection that correlates with restraint of the WNV-directed cytolytic response. We hypothesize that this regulatory T cell response sufficiently restrains the immune response such that a chronic infection can be maintained in the CNS. Use of this new mouse model of chronic neuroinvasive virus will be critical in developing improved strategies to prevent prolonged disease in humans.

Esophageal Cancer: Insights from Mouse Models

Directory of Open Access Journals (Sweden)

Marie-Pier Tétreault

2015-01-01

Full Text Available Esophageal cancer is the eighth leading cause of cancer and the sixth most common cause of cancer-related death worldwide. Despite recent advances in the development of surgical techniques in combination with the use of radiotherapy and chemotherapy, the prognosis for esophageal cancer remains poor. The cellular and molecular mechanisms that drive the pathogenesis of esophageal cancer are still poorly understood. Hence, understanding these mechanisms is crucial to improving outcomes for patients with esophageal cancer. Mouse models constitute valuable tools for modeling human cancers and for the preclinical testing of therapeutic strategies in a manner not possible in human subjects. Mice are excellent models for studying human cancers because they are similar to humans at the physiological and molecular levels and because they have a shorter gestation time and life cycle. Moreover, a wide range of well-developed technologies for introducing genetic modifications into mice are currently available. In this review, we describe how different mouse models are used to study esophageal cancer.

Finite Element Implementation of a Glass Tempering Model in Three Dimensions

DEFF Research Database (Denmark)

Nielsen, Jens Henrik; Olesen, John Forbes; Poulsen, Peter Noe

2010-01-01

The present paper develops and validates a 3D model for the simulation of glass tempering. It is assembled from well-known models of temperature dependent viscoelasticity and structural relaxation and predicts both transient and steady-state stresses in complex 3D glass geometries. The theory and...

Using the mouse to model human disease: increasing validity and reproducibility

Directory of Open Access Journals (Sweden)

Monica J. Justice

2016-02-01

Full Text Available Experiments that use the mouse as a model for disease have recently come under scrutiny because of the repeated failure of data, particularly derived from preclinical studies, to be replicated or translated to humans. The usefulness of mouse models has been questioned because of irreproducibility and poor recapitulation of human conditions. Newer studies, however, point to bias in reporting results and improper data analysis as key factors that limit reproducibility and validity of preclinical mouse research. Inaccurate and incomplete descriptions of experimental conditions also contribute. Here, we provide guidance on best practice in mouse experimentation, focusing on appropriate selection and validation of the model, sources of variation and their influence on phenotypic outcomes, minimum requirements for control sets, and the importance of rigorous statistics. Our goal is to raise the standards in mouse disease modeling to enhance reproducibility, reliability and clinical translation of findings.

THERMODYNAMIC MODEL AND VISCOSITY OF SELECTED ZIRCONIA CONTAINING SILICATE GLASSES

Directory of Open Access Journals (Sweden)

MÁRIA CHROMČÍKOVÁ

2013-03-01

Full Text Available The compositional dependence of viscosity, and viscous flow activation energy of glasses with composition xNa2O∙(15-x K2O∙yCaO∙(10-yZnO∙zZrO2∙(75-zSiO2 (x = 0, 7.5, 15; y = 0, 5, 10; z = 0, 1, 3, 5, 7 was analyzed. The studied glasses were described by the thermodynamic model of Shakhmatkin and Vedishcheva considering the glass as an equilibrium ideal solution of species with stoichiometry given by the composition of stable crystalline phases of respective glass forming system. Viscosity-composition relationships were described by the regression approach considering the viscous flow activation energy and the particular isokome temperature as multilinear function of equilibrium molar amounts of system components. The classical approach where the mole fractions of individual oxides are considered as independent variables was compared with the thermodynamic model. On the basis of statistical analysis there was proved that the thermodynamic model is able to describe the composition property relationships with higher reliability. Moreover, due its better physical justification, thermodynamic model can be even used for predictive purposes.

Modeling a novel glass immobilization waste treatment process using flow

International Nuclear Information System (INIS)

Ferrada, J.J.; Nehls, J.W. Jr.; Welch, T.D.; Giardina, J.L.

1996-01-01

One option for control and disposal of surplus fissile materials is the Glass Material Oxidation and Dissolution System (GMODS), a process developed at ORNL for directly converting Pu-bearing material into a durable high-quality glass waste form. This paper presents a preliminary assessment of the GMODS process flowsheet using FLOW, a chemical process simulator. The simulation showed that the glass chemistry postulated ion the models has acceptable levels of risks

Serial micro-CT assessment of the therapeutic effects of rosiglitazone in a bleomycin-induced lung fibrosis mouse model

Energy Technology Data Exchange (ETDEWEB)

Choi, Eun Jung; Jin, Gong Yong; Bok, Se Mi; Han, Young Min; Lee, Young Sun; Jung, Myung Ja; Kwon, Keun Sang [Research Institute of Clinical Medicine of Chonbuk National University, Biomedical Research Institute of Chonbuk National University Hospital, Institute for Medical Sciences, Jeonju (Korea, Republic of)

2014-08-15

The aim of this study was to assess the therapeutic effects of rosiglitazone with serial micro-CT findings before and after rosiglitazone administration in a lung fibrosis mouse model induced with bleomycin. We instilled the bleomycin solution directly into the trachea in twenty mice (female, C57BL/6 mice). After the instillation with bleomycin, mice were closely observed for 3 weeks and then all mice were scanned using micro-CT without sacrifice. At 3 weeks, the mice were treated with rosiglitazone on days 21 to 27 if they had abnormal CT findings (n = 9, 45%). For the mice treated with rosiglitazone, we performed micro-CT with mouse sacrifice 2 weeks after the rosiglitazone treatment completion. We assessed the abnormal CT findings (ground glass attenuation, consolidation, bronchiectasis, reticular opacity, and honeycombing) using a five-point scale at 3 and 6 weeks using Wilcoxon-signed ranked test. The micro-CT findings were correlated with the histopathologic results. One out of nine (11.1%) mice improved completely. In terms of consolidation, all mice (100%) showed marked decrease from 3.1 ± 1.4 at 3 weeks to 0.9 ± 0.9 at 6 weeks (p = 0.006). At 6 weeks, mild bronchiectasis (n = 6, 66.7%), mild reticular opacity (n 7, 77.8%) and mild honeycomb patterns (n = 3, 33.3%) appeared. A serial micro-CT enables the evaluation of drug effects in a lung fibrosis mouse model.

Comprehension and modelling of chromia-forming alloys corrosion mechanisms in nuclear glasses

International Nuclear Information System (INIS)

Schmucker, Eric

2016-01-01

Nuclear wastes management consists in the confinement of the radioactive wastes in a glass matrix. This is made by inductive melting in a hot crucible at an operating temperature around 1150 C. These crucibles are constituted of nickel based superalloys with high chromium content. They are submitted to a harsh corrosion by the molten glass, eventually leading to their replacement. The protection of the crucible against corrosion is best provided by the establishment of a protective chromium oxide layer at the surface of the alloy. A binary chromia-forming alloy (Ni-30Cr) is studied in this work. Three different binary and ternary glass compositions are chosen in order to understand the influence of the glass basicity and glass viscosity on the corrosion kinetics. Besides, the de-correlation of the formation and dissolution kinetics of the oxide layer allows the modelling of the overall oxide growth in the molten glass. For that purpose, the oxide formation kinetics in molten glass media is assimilated to the oxidation kinetics of the alloy in gaseous media with oxygen partial pressure that are representative of the redox properties of the glasses. Studies of the oxidation kinetics and of the diffusion mechanisms have shown that the oxidation kinetics is independent on the oxygen pressure in the range of 10"-"1"3 up to 10"-"3 atm O_2 at 1150 C. The present work has shown that the dissolution kinetics of the oxide layer is governed by the diffusion of Cr(III) in the glass melt. This dissolution kinetics has been evaluated from the diffusion coefficient and the solubility limit of Cr(III) in the glass. Finally, the overall growth kinetics of the Cr_2O_3 layer in the glass has been successfully modelled for each glass, thanks to the knowledge of (i) the solubility limit of Cr(III), (ii) its diffusion coefficient in the glasses and (iii) the oxidation kinetics of the alloy. The presented model also allows quantifying the influence of each of these parameters on the

Kovacs effect in solvable model glasses

International Nuclear Information System (INIS)

Aquino, Gerardo; Leuzzi, Luca; Nieuwenhuizen, Theo M

2006-01-01

The Kovacs protocol, based on the temperature shift experiment originally conceived by A.J. Kovacs and applied on glassy polymers, is implemented in an exactly solvable model with facilitated dynamics. This model is based on interacting fast and slow modes represented respectively by spherical spins and harmonic oscillator variables. Due to this fundamental property and to slow dynamics, the model reproduces the characteristic nonmonotonic evolution known as the 'Kovacs effect', observed in polymers, spin glasses, in granular materials and models of molecular liquids, when similar experimental protocols are implemented

Kovacs effect in solvable model glasses

Science.gov (United States)

Aquino, Gerardo; Leuzzi, Luca; Nieuwenhuizen, Theo M.

2006-05-01

The Kovacs protocol, based on the temperature shift experiment originally conceived by A.J. Kovacs and applied on glassy polymers [1], is implemented in an exactly solvable model with facilitated dynamics. This model is based on interacting fast and slow modes represented respectively by spherical spins and harmonic oscillator variables. Due to this fundamental property and to slow dynamics, the model reproduces the characteristic nonmonotonic evolution known as the ''Kovacs effect'', observed in polymers, spin glasses, in granular materials and models of molecular liquids, when similar experimental protocols are implemented.

Short range structural models of the glass transition temperatures and densities of 0.5Na2S + 0.5[xGeS2 + (1 - x)PS5/2] mixed glass former glasses.

Science.gov (United States)

Bischoff, Christian; Schuller, Katherine; Martin, Steve W

2014-04-03

The 0.5Na2S + 0.5[xGeS2 + (1 - x)PS5/2] mixed glass former (MGF) glass system exhibits a nonlinear and nonadditive negative change in the Na(+) ion conductivity as one glass former, PS5/2, is exchanged for the other, GeS2. This behavior, known as the mixed glass former effect (MGFE), is also manifest in a negative deviation from the linear interpolation of the glass transition temperatures (T(g)) of the binary end-member glasses, x = 0 and x = 1. Interestingly, the composition dependence of the densities of these ternary MGF glasses reveals a slightly positive MGFE deviation from a linear interpolation of the densities of the binary end-member glasses, x = 0 and x = 1. From our previous studies of the structures of these glasses using IR, Raman, and NMR spectroscopies, we find that a disproportionation reaction occurs between PS7/2(4-) and GeS3(2-) units into PS4(3-) and GeS5/2(1-) units. This disproportionation combined with the formation of Ge4S10(4-) anions from GeS5/2(1-) groups leads to the negative MGFE in T(g). A best-fit model of the T(g)s of these glasses was developed to quantify the amount of GeS5/2(1-) units that form Ge4S10(4-) molecular anions in the ternary glasses (∼ 5-10%). This refined structural model was used to develop a short-range structural model of the molar volumes, which shows that the slight densification of the ternary glasses is due to the improved packing efficiency of the germanium sulfide species.

Modeling interfacial glass-water reactions: recent advances and current limitations

International Nuclear Information System (INIS)

Pierce, Eric M.; Frugier, Pierre; Criscenti, Louise J.; Kwon, Kideok D.; Kerisit, Sebastien N.

2014-01-01

Describing the reactions that occur at the glass-water interface and control the development of the altered layer constitutes one of the main scientific challenges impeding existing models from providing accurate radionuclide release estimates. Radionuclide release estimates are a critical component of the safety basis for geologic repositories. The altered layer (i.e., amorphous hydrated surface layer and crystalline reaction products) represents a complex region, both physically and chemically, sandwiched between two distinct boundaries-pristine glass surface at the inner most interface and aqueous solution at the outer most interface. Computational models, spanning different length and timescales, are currently being developed to improve our understanding of this complex and dynamic process with the goal of accurately describing the mesoscale changes that occur as the system evolves. These modeling approaches include geochemical simulations (i.e., classical reaction path simulations and glass reactivity in allowance for alteration layer simulations), Monte Carlo simulations, and molecular dynamics methods. Discussed in this manuscript are the advances and limitations of each modeling approach placed in the context of the glass-water reaction and how collectively these approaches provide insights into the mechanisms that control the formation and evolution of altered layers. New results are presented as examples of each approach. (authors)

Mechanistic interpretation of glass reaction: Input to kinetic model development

International Nuclear Information System (INIS)

Bates, J.K.; Ebert, W.L.; Bradley, J.P.; Bourcier, W.L.

1991-05-01

Actinide-doped SRL 165 type glass was reacted in J-13 groundwater at 90 degree C for times up to 278 days. The reaction was characterized by both solution and solid analyses. The glass was seen to react nonstoichiometrically with preferred leaching of alkali metals and boron. High resolution electron microscopy revealed the formation of a complex layer structure which became separated from the underlying glass as the reaction progressed. The formation of the layer and its effect on continued glass reaction are discussed with respect to the current model for glass reaction used in the EQ3/6 computer simulation. It is concluded that the layer formed after 278 days is not protective and may eventually become fractured and generate particulates that may be transported by liquid water. 5 refs., 5 figs. , 3 tabs

Liquid-liquid phase transition and glass transition in a monoatomic model system.

Science.gov (United States)

Xu, Limei; Buldyrev, Sergey V; Giovambattista, Nicolas; Stanley, H Eugene

2010-01-01

We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses.

Liquid-Liquid Phase Transition and Glass Transition in a Monoatomic Model System

Directory of Open Access Journals (Sweden)

Nicolas Giovambattista

2010-12-01

Full Text Available We review our recent study on the polyamorphism of the liquid and glass states in a monatomic system, a two-scale spherical-symmetric Jagla model with both attractive and repulsive interactions. This potential with a parametrization for which crystallization can be avoided and both the glass transition and the liquid-liquid phase transition are clearly separated, displays water-like anomalies as well as polyamorphism in both liquid and glassy states, providing a unique opportunity to study the interplay between the liquid-liquid phase transition and the glass transition. Our study on a simple model may be useful in understanding recent studies of polyamorphism in metallic glasses.

Global gene expression analysis in a mouse model for Norrie disease: late involvement of photoreceptor cells.

Science.gov (United States)

Lenzner, Steffen; Prietz, Sandra; Feil, Silke; Nuber, Ulrike A; Ropers, H-Hilger; Berger, Wolfgang

2002-09-01

Mutations in the NDP gene give rise to a variety of eye diseases, including classic Norrie disease (ND), X-linked exudative vitreoretinopathy (EVRX), retinal telangiectasis (Coats disease), and advanced retinopathy of prematurity (ROP). The gene product is a cystine-knot-containing extracellular signaling molecule of unknown function. In the current study, gene expression was determined in a mouse model of ND, to unravel disease-associated mechanisms at the molecular level. Gene transcription in the eyes of 2-year-old Ndp knockout mice was compared with that in the eyes of age-matched wild-type control animals, by means of cDNA subtraction and microarrays. Clones (n = 3072) from the cDNA subtraction libraries were spotted onto glass slides and hybridized with fluorescently labeled RNA-derived targets. More than 230 differentially expressed clones were sequenced, and their expression patterns were verified by virtual Northern blot analysis. Numerous gene transcripts that are absent or downregulated in the eye of Ndp knockout mice are photoreceptor cell specific. In younger Ndp knockout mice (up to 1 year old), however, all these transcripts were found to be expressed at normal levels. The identification of numerous photoreceptor cell-specific transcripts with a reduced expression in 2-year-old, but not in young, Ndp knockout mice indicates that normal gene expression in these light-sensitive cells of mutant mice is established and maintained over a long period and that rods and cones are affected relatively late in the mouse model of ND. Obviously, the absence of the Ndp gene product is not compatible with long-term survival of photoreceptor cells in the mouse.

Modeling glass transition and aging processes in nanocomposites and polymer thin films

Science.gov (United States)

Pryamitsyn, Victor; Ganesan, Venkat

2010-03-01

We use a lattice kinetic model of glass transition to study the role of confinement and the presence of nano-inclusions. We have studied freely suspended films of glass-formers and its nanocomposites with ``plastifying'' and ``hardening'' nanoparticles. Using our model we determine the thickness and nanoparticle load dependencies of the Kauzmann temperature T0 and the fragility parameter. We found the glass transition temperature increases with the thickness of the film and the volume fraction of ``hardening'' nanoparticles , while Tg decreases with increase in the loading of ``plastifying'' nanoparticles. We found that the isothermal free volume relaxation rate of the nanocomposite thin film, usually referred as an aging, correlates with the glass transition temperature shift. We also studied the relations between our lattice model and Curro's, Kovacs and Struik's phenomenological models of free volume reduction to deduce physical insights into the mechanisms governing aging processes in thin films and nanocomposites.

A toy MCT model for multiple glass transitions: Double swallow tail singularity

Energy Technology Data Exchange (ETDEWEB)

Ryzhov, V.N. [Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk 142190, Moscow region (Russian Federation); Moscow Institute of Physics and Technology, 141700 Moscow (Russian Federation); Tareyeva, E.E. [Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk 142190, Moscow region (Russian Federation)

2014-11-07

We propose a toy model to describe in the frame of Mode Coupling Theory multiple glass transitions. The model is based on the postulated simple form for static structure factor as a sum of two delta-functions. This form makes it possible to solve the MCT equations in almost analytical way. The phase diagram is governed by two swallow tails resulting from two A{sub 4} singularities and includes liquid–glass transition and multiple glasses. The diagram has much in common with those of binary and quasibinary systems. - Highlights: • A simple toy model is proposed for description of glass–glass transitions. • The static structure factor of the model has the form of a sum of delta-functions. • The phase diagram contains A{sub 4} bifurcation singularities and A{sub 3} end points. • The results can be applied for the qualitative description of quasibinary systems.

Property-Composition-Temperature Modeling of Waste Glass Melt Data Subject to a Randomization Restriction

International Nuclear Information System (INIS)

Piepel, Gregory F.; Heredia-Langner, Alejandro; Cooley, Scott K.

2008-01-01

Properties such as viscosity and electrical conductivity of glass melts are functions of melt temperature as well as glass composition. When measuring such a property for several glasses, the property is typically measured at several temperatures for one glass, then at several temperatures for the next glass, and so on. This data-collection process involves a restriction on randomization, which is referred to as split-plot experiment. The split-plot data structure must be accounted for in developing property-composition-temperature models and the corresponding uncertainty equations for model predictions. Instead of ordinary least squares (OLS) regression methods, generalized least squares (GLS) regression methods using restricted maximum likelihood (REML) estimation must be used. This article describes the methodology for developing property-composition-temperature models and corresponding prediction uncertainty equations using the GLS/REML regression approach. Viscosity data collected on 197 simulated nuclear waste glasses are used to illustrate the GLS/REML methods for developing a viscosity-composition-temperature model and corresponding equations for model prediction uncertainties. The correct results using GLS/REML regression are compared to the incorrect results obtained using OLS regression

Experimental photoallergic contact dermatitis: a mouse model

International Nuclear Information System (INIS)

Maguire, H.C. Jr.; Kaidbey, K.

1982-01-01

We have induced photoallergic contact dermatitis in mice to 3,3',4',5 tetrachlorosalicylanilide (TCSA), chlorpromazine and 6-methylcoumarin. These compounds are known to produce photoallergic contact dermatitis in humans. The photoallergic contact dermatitis reaction in the mouse is immunologically specific viz. mice photosensitized to TCSA react, by photochallenge, to that compound and not to chlorpromazine, and conversely. The reaction requires UVA at both sensitization and challenge. It appears to be T-cell mediated in that it can be passively transferred to syngeneic mice by lymph node cells from actively sensitized mice, the histology of the reactions resembles that of classic allergic contact dermatitis in mice, challenge reactions are seen at 24 but not at 4 hr, and photoallergic contact dermatitis can be induced in B-cell deficient mice. The availability of a mouse model for the study of photo-ACD will facilitate the identification of pertinent control mechanisms and may aid in the management of the disease. It is likely that a bioassay for photoallergens of humans can be based on this mouse model

Modelling glass alteration in an altered argillaceous environment

International Nuclear Information System (INIS)

Bildstein, O.; Trotignon, L.; Pozo, C.; Jullien, M.

2007-01-01

The long term behaviour of materials such as glass, steel and clay has been investigated in the context of deep geological disposal of radioactive wastes. The interactions between vitrified wastes, canister corrosion products (CPs) and clay are studied using a modified version of the reaction-transport code Crunch, especially looking at pH changes and possible cementation at the interface with the clayey materials. These perturbations may indeed affect the lifetime of glass matrix in deep repositories, e.g., high pH enhances the rate of glass alteration. This work focuses on the argillite of Bure. The calculations were performed at 323 K with a glass alteration rate switching from a high initial rate to a residual rate according to the sorption capacity of CPs. The time at which this sorption capacity is saturated is crucial to the system in terms of wastes package lifetime. The results show that the glass alteration imposes a high pH value at the interface with CPs and clay: up to a value of 9.2, compared to 7.3 which is the initial pH value in the argillite. Experimental data show that the rate of glass alteration is much higher in such pH conditions. For a R7T7-type glass, the rate is about five times higher at pH 9 than at pH 7. This pH perturbation migrates through the clayey domain as a result of the migration of mobile elements such as boron and sodium, and despite the existence of strong pH buffers in the argillite. The cementation of porosity at the interface between glass and clay is predicted by the model due to the massive precipitation of iron corrosion products and glass alteration products. At this point of the evolution of the system, the pH starts to decrease and the alteration rate of the glass could be significantly reduced. This porosity clogging effect is difficult to confirm by experiments especially since existing data on short term experiments tend to show a pervasive precipitation of silica in the domain instead of a localized precipitation

Heat Transfer Modelling of Glass Media within TPV Systems

Science.gov (United States)

Bauer, Thomas; Forbes, Ian; Penlington, Roger; Pearsall, Nicola

2004-11-01

Understanding and optimisation of heat transfer, and in particular radiative heat transfer in terms of spectral, angular and spatial radiation distributions is important to achieve high system efficiencies and high electrical power densities for thermophtovoltaics (TPV). This work reviews heat transfer models and uses the Discrete Ordinates method. Firstly one-dimensional heat transfer in fused silica (quartz glass) shields was examined for the common arrangement, radiator-air-glass-air-PV cell. It has been concluded that an alternative arrangement radiator-glass-air-PV cell with increased thickness of fused silica should have advantages in terms of improved transmission of convertible radiation and enhanced suppression of non-convertible radiation.

JSS project phase 4: Experimental and modelling studies of HLW glass dissolution in repository environments

International Nuclear Information System (INIS)

1987-10-01

A goal of the JSS project was to develop a scientific basis for understanding the effects of waste package components, groundwater chemistry, and other repository conditions on glass dissolution behaviour, and to develop and refine a model for the processes governing glass dissolution. The fourth phase of the project, which was performed by the Hahn-Meitner-Institut, Berlin, FRG, dealt specifically with model development and application. Phase 4 also adressed whether basaltic glasses could serve as natural analogues for nuclear waste glasses, thus providing a means to test the capability of the model for long-term predictions. Additional experiments were performed in order to complete the data base necessary to model interactions between the glass and bentonite and between glass and steel corrosion products. More data on temperature, S/V, and pH dependence of the glass/water reaction were also collected. In this report, the data acquired during phase 4 are presented and discussed. (orig./DG)

Transgenic mouse models of hormonal mammary carcinogenesis: advantages and limitations.

Science.gov (United States)

Kirma, Nameer B; Tekmal, Rajeshwar R

2012-09-01

Mouse models of breast cancer, especially transgenic and knockout mice, have been established as valuable tools in shedding light on factors involved in preneoplastic changes, tumor development and malignant progression. The majority of mouse transgenic models develop estrogen receptor (ER) negative tumors. This is seen as a drawback because the majority of human breast cancers present an ER positive phenotype. On the other hand, several transgenic mouse models have been developed that produce ER positive mammary tumors. These include mice over-expressing aromatase, ERα, PELP-1 and AIB-1. In this review, we will discuss the value of these models as physiologically relevant in vivo systems to understand breast cancer as well as some of the pitfalls involving these models. In all, we argue that the use of transgenic models has improved our understanding of the molecular aspects and biology of breast cancer. Copyright © 2011 Elsevier Ltd. All rights reserved.

Physical-chemical model for the mechanism of glass corrosion with particular consideration of simulated radioactive waste glasses

International Nuclear Information System (INIS)

Grambow, B.

1985-01-01

A physical-chemical model for the mechanism of glass corrosion is described. This model can be used for predicting, interpreting, and extrapolating experimental results. In static leaching tests the rate of corrosion generally decreases with time. Some authors assume that the surface layer, which grows during the course of the reaction, protects the underlying glass from further attack by the aqueous phase. Other authors assume that the saturation effects in solution are responsible for reducing the rate of the reaction. It is demonstrated within the scope of this work that examples can be found for both concepts; however, transport processes in the surface layer and/or in solution can be excluded as rate-determining processes within a majority of the examined cases. The location of the corrosion reaction is the boundary surface between the surface layer and the not yet attacked glass (transition zone)

The glass-forming ability of model metal-metalloid alloys

Energy Technology Data Exchange (ETDEWEB)

Zhang, Kai; Liu, Yanhui; Schroers, Jan [Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520 (United States); Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520 (United States); Shattuck, Mark D. [Department of Physics and Benjamin Levich Institute, The City College of the City University of New York, New York, New York 10031 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520 (United States); O’Hern, Corey S. [Department of Mechanical Engineering and Materials Science, Yale University, New Haven, Connecticut 06520 (United States); Center for Research on Interface Structures and Phenomena, Yale University, New Haven, Connecticut 06520 (United States); Department of Physics, Yale University, New Haven, Connecticut 06520 (United States); Department of Applied Physics, Yale University, New Haven, Connecticut 06520 (United States)

2015-03-14

Bulk metallic glasses (BMGs) are amorphous alloys with desirable mechanical properties and processing capabilities. To date, the design of new BMGs has largely employed empirical rules and trial-and-error experimental approaches. Ab initio computational methods are currently prohibitively slow to be practically used in searching the vast space of possible atomic combinations for bulk glass formers. Here, we perform molecular dynamics simulations of a coarse-grained, anisotropic potential, which mimics interatomic covalent bonding, to measure the critical cooling rates for metal-metalloid alloys as a function of the atomic size ratio σ{sub S}/σ{sub L} and number fraction x{sub S} of the metalloid species. We show that the regime in the space of σ{sub S}/σ{sub L} and x{sub S} where well-mixed, optimal glass formers occur for patchy and LJ particle mixtures, coincides with that for experimentally observed metal-metalloid glass formers. Thus, our simple computational model provides the capability to perform combinatorial searches to identify novel glass-forming alloys.

Study of archaeological analogs for the validation of nuclear glass long-term behavior models

International Nuclear Information System (INIS)

Verney-Carron, A.

2008-10-01

Fractured archaeological glass blocks collected from a shipwreck discovered in the Mediterranean Sea near Embiez Island (Var) were investigated because of their morphological analogy with vitrified nuclear waste and of a known and stable environment. These glasses are fractured due to a fast cooling after they were melted (like nuclear glass) and have been altered for 1800 years in seawater. This work results in the development and the validation of a geochemical model able to simulate the alteration of a fractured archaeological glass block over 1800 years. The kinetics associated with the different mechanisms (interdiffusion and dissolution) and the thermodynamic parameters of the model were determined by leaching experiments. The model implemented in HYTEC software was used to simulate crack alteration over 1800 years. The consistency between simulated alteration thicknesses and measured data on glass blocks validate the capacity of the model to predict long-term alteration. This model is able to account for the results from the characterization of crack network and its state of alteration. The cracks in the border zone are the most altered due to a fast renewal of the leaching solution, whereas internal cracks are thin because of complex interactions between glass alteration and transport of elements in solution (influence of initial crack aperture and of the crack sealing). The lowest alteration thicknesses, as well as their variability, can be explained. The analog behavior of archaeological and nuclear glasses from leaching experiments makes possible the transposition of the model to nuclear glass in geological repository. (author)

Modeling the kinetics of volatilization from glass melts

NARCIS (Netherlands)

Beerkens, R.G.C.

2001-01-01

A model description for the evaporation kinetics from glass melts in direct contact with static atmospheres or flowing gas phases is presented. The derived models and equations are based on the solution of the second Ficks' diffusion law and quasi-steady-state mass transfer relations, taking into

Evaporation experiments and modelling for glass melts

NARCIS (Netherlands)

Limpt, J.A.C. van; Beerkens, R.G.C.

2007-01-01

A laboratory test facility has been developed to measure evaporation rates of different volatile components from commercial and model glass compositions. In the set-up the furnace atmosphere, temperature level, gas velocity and batch composition are controlled. Evaporation rates have been measured

Progress toward bridging from atomistic to continuum modeling to predict nuclear waste glass dissolution.

Energy Technology Data Exchange (ETDEWEB)

Zapol, Peter (Argonne National Laboratory, Argonne, IL); Bourg, Ian (Lawrence Berkeley National Laboratories, Berkeley, CA); Criscenti, Louise Jacqueline; Steefel, Carl I. (Lawrence Berkeley National Laboratories, Berkeley, CA); Schultz, Peter Andrew

2011-10-01

This report summarizes research performed for the Nuclear Energy Advanced Modeling and Simulation (NEAMS) Subcontinuum and Upscaling Task. The work conducted focused on developing a roadmap to include molecular scale, mechanistic information in continuum-scale models of nuclear waste glass dissolution. This information is derived from molecular-scale modeling efforts that are validated through comparison with experimental data. In addition to developing a master plan to incorporate a subcontinuum mechanistic understanding of glass dissolution into continuum models, methods were developed to generate constitutive dissolution rate expressions from quantum calculations, force field models were selected to generate multicomponent glass structures and gel layers, classical molecular modeling was used to study diffusion through nanopores analogous to those in the interfacial gel layer, and a micro-continuum model (K{mu}C) was developed to study coupled diffusion and reaction at the glass-gel-solution interface.

Haw-glass dissolution and radionuclide release: mechanism - modelling - source term

Energy Technology Data Exchange (ETDEWEB)

Grambow, B [Forschungszentrum Karlsruhe, Institut fur Nukleare, Karlsruhe (Germany)

1997-07-01

Important release controlling processes are: 1) kinetics of glass matrix dissolution (leaching), 2) formation of secondary alteration products (controlling thermodynamic solubility), 3) sorption on surfaces in the engineered barrier system and 4) formation of mobile species. Quantification of these processes requires assessment of the energetics and dynamics of the various reversible and irreversible processes within an overall open non-equilibrium system. Corrosion/dissolution of the waste matrices is not necessarily associated with a proportional release of radionuclides. The formation of new secondary phases, such as silicates, molybdates, uranates, carbonates... establishes a new geochemical barrier for re-immobilization of radionuclides dissolved from the waste matrices. The presence of iron (corroding canisters during glass alteration) reduces the solution concentration of redox sensitive radionuclides. Consequently, the container, after being corroded, constitutes an important geochemical barrier for radionuclide re-immobilization. Geochemical modelling of the long-term behaviour of glasses must be performed in an integrated way, considering simultaneous reactions of the glass, of container corrosion, of repository rock and of backfill material. Until now, only few attempts were made for integral systems modelling. (A.C.)

Correlation between relaxations and plastic deformation, and elastic model of flow in metallic glasses and glass-forming liquids

International Nuclear Information System (INIS)

Wang Weihua

2011-01-01

We study the similarity and correlations between relaxations and plastic deformation in metallic glasses (MGs) and MG-forming liquids. It is shown that the microscope plastic events, the initiation and formation of shear bands, and the mechanical yield in MGs where the atomic sites are topologically unstable induced by applied stress, can be treated as the glass to supercooled liquid state transition induced by external shear stress. On the other hand, the glass transition, the primary and secondary relaxations, plastic deformation and yield can be attributed to the free volume increase induced flow, and the flow can be modeled as the activated hopping between the inherent states in the potential energy landscape. We then propose an extended elastic model to describe the flow based on the energy landscape theory. That is, the flow activation energy density is linear proportional to the instantaneous elastic moduli, and the activation energy density ρ E is determined to be a simple expression of ρ E =(10/11)G+(1/11)K. The model indicates that both shear and bulk moduli are critical parameters accounting for both the homogeneous and inhomogeneous flows in MGs and MG-forming liquids. The elastic model is experimentally certified. We show that the elastic perspectives offers a simple scenario for the flow in MGs and MG-forming liquids and are suggestive for understanding the glass transition, plastic deformation, and nature and characteristics of MGs

A metabolomic comparison of mouse models of the Neuronal Ceroid Lipofuscinoses

Energy Technology Data Exchange (ETDEWEB)

Salek, Reza M.; Pears, Michael R. [University of Cambridge, Department of Biochemistry and Cambridge Systems Biology Centre (United Kingdom); Cooper, Jonathan D. [King' s College London, Pediatric Storage Disorders Laboratory, Department of Neuroscience, Institute of Psychiatry (United Kingdom); Mitchison, Hannah M. [Royal Free and University College Medical School, Department of Paediatrics and Child Health (United Kingdom); Pearce, David A. [Sanford School of Medicine of the University of South Dakota, Department of Pediatrics (United States); Mortishire-Smith, Russell J. [Johnson and Johnson PR and D (Belgium); Griffin, Julian L., E-mail: jlg40@mole.bio.cam.ac.uk [University of Cambridge, Department of Biochemistry and the Cambridge Systems Biology Centre (United Kingdom)

2011-04-15

The Neuronal Ceroid Lipofuscinoses (NCL) are a group of fatal inherited neurodegenerative diseases in humans distinguished by a common clinical pathology, characterized by the accumulation of storage body material in cells and gross brain atrophy. In this study, metabolic changes in three NCL mouse models were examined looking for pathways correlated with neurodegeneration. Two mouse models; motor neuron degeneration (mnd) mouse and a variant model of late infantile NCL, termed the neuronal ceroid lipofuscinosis (nclf) mouse were investigated experimentally. Both models exhibit a characteristic accumulation of autofluorescent lipopigment in neuronal and non neuronal cells. The NMR profiles derived from extracts of the cortex and cerebellum from mnd and nclf mice were distinguished according to disease/wildtype status. In particular, a perturbation in glutamine and glutamate metabolism, and a decrease in {gamma}-amino butyric acid (GABA) in the cerebellum and cortices of mnd (adolescent mice) and nclf mice relative to wildtype at all ages were detected. Our results were compared to the Cln3 mouse model of NCL. The metabolism of mnd mice resembled older (6 month) Cln3 mice, where the disease is relatively advanced, while the metabolism of nclf mice was more akin to younger (1-2 months) Cln3 mice, where the disease is in its early stages of progression. Overall, our results allowed the identification of metabolic traits common to all NCL subtypes for the three animal models.

A metabolomic comparison of mouse models of the Neuronal Ceroid Lipofuscinoses

International Nuclear Information System (INIS)

Salek, Reza M.; Pears, Michael R.; Cooper, Jonathan D.; Mitchison, Hannah M.; Pearce, David A.; Mortishire-Smith, Russell J.; Griffin, Julian L.

2011-01-01

The Neuronal Ceroid Lipofuscinoses (NCL) are a group of fatal inherited neurodegenerative diseases in humans distinguished by a common clinical pathology, characterized by the accumulation of storage body material in cells and gross brain atrophy. In this study, metabolic changes in three NCL mouse models were examined looking for pathways correlated with neurodegeneration. Two mouse models; motor neuron degeneration (mnd) mouse and a variant model of late infantile NCL, termed the neuronal ceroid lipofuscinosis (nclf) mouse were investigated experimentally. Both models exhibit a characteristic accumulation of autofluorescent lipopigment in neuronal and non neuronal cells. The NMR profiles derived from extracts of the cortex and cerebellum from mnd and nclf mice were distinguished according to disease/wildtype status. In particular, a perturbation in glutamine and glutamate metabolism, and a decrease in γ-amino butyric acid (GABA) in the cerebellum and cortices of mnd (adolescent mice) and nclf mice relative to wildtype at all ages were detected. Our results were compared to the Cln3 mouse model of NCL. The metabolism of mnd mice resembled older (6 month) Cln3 mice, where the disease is relatively advanced, while the metabolism of nclf mice was more akin to younger (1-2 months) Cln3 mice, where the disease is in its early stages of progression. Overall, our results allowed the identification of metabolic traits common to all NCL subtypes for the three animal models.

Anelastic deformation processes in metallic glasses and activation energy spectrum model

NARCIS (Netherlands)

Ocelik, [No Value; Csach, K; Kasardova, A; Bengus, VZ; Ocelik, Vaclav

1997-01-01

The isothermal kinetics of anelastic deformation below the glass transition temperature (so-called 'stress induced ordering' or 'creep recovery' deformation) was investigated in Ni-Si-B metallic glass. The relaxation time spectrum model and two recently developed methods for its calculation from the

Long-term modeling of glass waste in portland cement- and clay-based matrices

International Nuclear Information System (INIS)

Stockman, H.W.; Nagy, K.L.; Morris, C.E.

1995-12-01

A set of ''templates'' was developed for modeling waste glass interactions with cement-based and clay-based matrices. The templates consist of a modified thermodynamic database, and input files for the EQ3/6 reaction path code, containing embedded rate models and compositions for waste glass, cement, and several pozzolanic materials. Significant modifications were made in the thermodynamic data for Th, Pb, Ra, Ba, cement phases, and aqueous silica species. It was found that the cement-containing matrices could increase glass corrosion rates by several orders of magnitude (over matrixless or clay matrix systems), but they also offered the lowest overall solubility for Pb, Ra, Th and U. Addition of pozzolans to cement decreased calculated glass corrosion rates by up to a factor of 30. It is shown that with current modeling capabilities, the ''affinity effect'' cannot be trusted to passivate glass if nuclei are available for precipitation of secondary phases that reduce silica activity

Humanized mouse models: Application to human diseases.

Science.gov (United States)

Ito, Ryoji; Takahashi, Takeshi; Ito, Mamoru

2018-05-01

Humanized mice are superior to rodents for preclinical evaluation of the efficacy and safety of drug candidates using human cells or tissues. During the past decade, humanized mouse technology has been greatly advanced by the establishment of novel platforms of genetically modified immunodeficient mice. Several human diseases can be recapitulated using humanized mice due to the improved engraftment and differentiation capacity of human cells or tissues. In this review, we discuss current advanced humanized mouse models that recapitulate human diseases including cancer, allergy, and graft-versus-host disease. © 2017 Wiley Periodicals, Inc.

Mouse models of estrogen receptor-positive breast cancer

Directory of Open Access Journals (Sweden)

Shakur Mohibi

2011-01-01

Full Text Available Breast cancer is the most frequent malignancy and second leading cause of cancer-related deaths among women. Despite advances in genetic and biochemical analyses, the incidence of breast cancer and its associated mortality remain very high. About 60 - 70% of breast cancers are Estrogen Receptor alpha (ER-α positive and are dependent on estrogen for growth. Selective estrogen receptor modulators (SERMs have therefore provided an effective targeted therapy to treat ER-α positive breast cancer patients. Unfortunately, development of resistance to endocrine therapy is frequent and leads to cancer recurrence. Our understanding of molecular mechanisms involved in the development of ER-α positive tumors and their resistance to ER antagonists is currently limited due to lack of experimental models of ER-α positive breast cancer. In most mouse models of breast cancer, the tumors that form are typically ER-negative and independent of estrogen for their growth. However, in recent years more attention has been given to develop mouse models that develop different subtypes of breast cancers, including ER-positive tumors. In this review, we discuss the currently available mouse models that develop ER-α positive mammary tumors and their potential use to elucidate the molecular mechanisms of ER-α positive breast cancer development and endocrine resistance.

Modeling principles applied to the simulation of a joule-heated glass melter

International Nuclear Information System (INIS)

Routt, K.R.

1980-05-01

Three-dimensional conservation equations applicable to the operation of a joule-heated glass melter were rigorously examined and used to develop scaling relationships for modeling purposes. By rigorous application of the conservation equations governing transfer of mass, momentum, energy, and electrical charge in three-dimensional cylindrical coordinates, scaling relationships were derived between a glass melter and a physical model for the following independent and dependent variables: geometrical size (scale), velocity, temperature, pressure, mass input rate, energy input rate, voltage, electrode current, electrode current flux, total power, and electrical resistance. The scaling relationships were then applied to the design and construction of a physical model of the semiworks glass melter for the Defense Waste Processing Facility. The design and construction of such a model using glycerine plus LiCl as a model fluid in a one-half-scale Plexiglas tank is described

Water leaching of borosilicate glasses: experiments, modeling and Monte Carlo simulations

International Nuclear Information System (INIS)

Ledieu, A.

2004-10-01

This work is concerned with the corrosion of borosilicate glasses with variable oxide contents. The originality of this study is the complementary use of experiments and numerical simulations. This study is expected to contribute to a better understanding of the corrosion of nuclear waste confinement glasses. First, the corrosion of glasses containing only silicon, boron and sodium oxides has been studied. The kinetics of leaching show that the rate of leaching and the final degree of corrosion sharply depend on the boron content through a percolation mechanism. For some glass contents and some conditions of leaching, the layer which appears at the glass surface stops the release of soluble species (boron and sodium). This altered layer (also called the gel layer) has been characterized with nuclear magnetic resonance (NMR) and small angle X-ray scattering (SAXS) techniques. Second, additional elements have been included in the glass composition. It appears that calcium, zirconium or aluminum oxides strongly modify the final degree of corrosion so that the percolation properties of the boron sub-network is no more a sufficient explanation to account for the behavior of these glasses. Meanwhile, we have developed a theoretical model, based on the dissolution and the reprecipitation of the silicon. Kinetic Monte Carlo simulations have been used in order to test several concepts such as the boron percolation, the local reactivity of weakly soluble elements and the restructuring of the gel layer. This model has been fully validated by comparison with the results on the three oxide glasses. Then, it has been used as a comprehensive tool to investigate the paradoxical behavior of the aluminum and zirconium glasses: although these elements slow down the corrosion kinetics, they lead to a deeper final degree of corrosion. The main contribution of this work is that the final degree of corrosion of borosilicate glasses results from the competition of two opposite mechanisms

Aqueous corrosion of borosilicate glasses: experiments, modeling and Monte-Carlo simulations

International Nuclear Information System (INIS)

Ledieu, A.

2004-10-01

This work is concerned with the corrosion of borosilicate glasses with variable oxide contents. The originality of this study is the complementary use of experiments and numerical simulations. This study is expected to contribute to a better understanding of the corrosion of nuclear waste confinement glasses. First, the corrosion of glasses containing only silicon, boron and sodium oxides has been studied. The kinetics of leaching show that the rate of leaching and the final degree of corrosion sharply depend on the boron content through a percolation mechanism. For some glass contents and some conditions of leaching, the layer which appears at the glass surface stops the release of soluble species (boron and sodium). This altered layer (also called the gel layer) has been characterized with nuclear magnetic resonance (NMR) and small angle X-ray scattering (SAXS) techniques. Second, additional elements have been included in the glass composition. It appears that calcium, zirconium or aluminum oxides strongly modify the final degree of corrosion so that the percolation properties of the boron sub-network is no more a sufficient explanation to account for the behavior of these glasses. Meanwhile, we have developed a theoretical model, based on the dissolution and the reprecipitation of the silicon. Kinetic Monte Carlo simulations have been used in order to test several concepts such as the boron percolation, the local reactivity of weakly soluble elements and the restructuring of the gel layer. This model has been fully validated by comparison with the results on the three oxide glasses. Then, it has been used as a comprehensive tool to investigate the paradoxical behavior of the aluminum and zirconium glasses: although these elements slow down the corrosion kinetics, they lead to a deeper final degree of corrosion. The main contribution of this work is that the final degree of corrosion of borosilicate glasses results from the competition of two opposite mechanisms

Regulatory Forum commentary: alternative mouse models for future cancer risk assessment.

Science.gov (United States)

Morton, Daniel; Sistare, Frank D; Nambiar, Prashant R; Turner, Oliver C; Radi, Zaher; Bower, Nancy

2014-07-01

International regulatory and pharmaceutical industry scientists are discussing revision of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use (ICH) S1 guidance on rodent carcinogenicity assessment of small molecule pharmaceuticals. A weight-of-evidence approach is proposed to determine the need for rodent carcinogenicity studies. For compounds with high human cancer risk, the product may be labeled appropriately without conducting rodent carcinogenicity studies. For compounds with minimal cancer risk, only a 6-month transgenic mouse study (rasH2 mouse or p53+/- mouse) or a 2-year mouse study would be needed. If rodent carcinogenicity testing may add significant value to cancer risk assessment, a 2-year rat study and either a 6-month transgenic mouse or a 2-year mouse study is appropriate. In many cases, therefore, one rodent carcinogenicity study could be sufficient. The rasH2 model predicts neoplastic findings relevant to human cancer risk assessment as well as 2-year rodent models, produces fewer irrelevant neoplastic outcomes, and often will be preferable to a 2-year rodent study. Before revising ICH S1 guidance, a prospective evaluation will be conducted to test the proposed weight-of-evidence approach. This evaluation offers an opportunity for a secondary analysis comparing the value of alternative mouse models and 2-year rodent studies in the proposed ICH S1 weight-of-evidence approach for human cancer risk assessment. © 2014 by The Author(s).

Mouse models of long QT syndrome

Science.gov (United States)

Salama, Guy; London, Barry

2007-01-01

Congenital long QT syndrome is a rare inherited condition characterized by prolongation of action potential duration (APD) in cardiac myocytes, prolongation of the QT interval on the surface electrocardiogram (ECG), and an increased risk of syncope and sudden death due to ventricular tachyarrhythmias. Mutations of cardiac ion channel genes that affect repolarization cause the majority of the congenital cases. Despite detailed characterizations of the mutated ion channels at the molecular level, a complete understanding of the mechanisms by which individual mutations may lead to arrhythmias and sudden death requires study of the intact heart and its modulation by the autonomic nervous system. Here, we will review studies of molecularly engineered mice with mutations in the genes (a) known to cause long QT syndrome in humans and (b) specific to cardiac repolarization in the mouse. Our goal is to provide the reader with a comprehensive overview of mouse models with long QT syndrome and to emphasize the advantages and limitations of these models. PMID:17038432

Defining the role of polyamines in colon carcinogenesis using mouse models

Directory of Open Access Journals (Sweden)

Natalia A Ignatenko

2011-01-01

Full Text Available Genetics and diet are both considered important risk determinants for colorectal cancer, a leading cause of death in the US and worldwide. Genetically engineered mouse (GEM models have made a significant contribution to the characterization of colorectal cancer risk factors. Reliable, reproducible, and clinically relevant animal models help in the identification of the molecular events associated with disease progression and in the development of effictive treatment strategies. This review is focused on the use of mouse models for studying the role of polyamines in colon carcinogenesis. We describe how the available mouse models of colon cancer such as the multiple intestinal neoplasia (Min mice and knockout genetic models facilitate understanding of the role of polyamines in colon carcinogenesis and help in the development of a rational strategy for colon cancer chemoprevention.

Three-Dimensional Numerical Modeling of Acoustic Trapping in Glass Capillaries

DEFF Research Database (Denmark)

Ley, Mikkel Wennemoes Hvitfeld; Bruus, Henrik

2017-01-01

Acoustic traps are used to capture and handle suspended microparticles and cells in microfluidic applications. A particular simple and much-used acoustic trap consists of a commercially available, millimeter-sized, liquid-filled straight glass capillary actuated by a piezoelectric transducer. Here......, we present a three-dimensional numerical model of the acoustic pressure field in the liquid coupled to the displacement field of the glass wall, taking into account mixed standing and traveling waves as well as absorption. The model explains the dynamical mechanism that leads to the formation...

Mass spectrometry analysis of hepcidin peptides in experimental mouse models.

Directory of Open Access Journals (Sweden)

Harold Tjalsma

Full Text Available The mouse is a valuable model for unravelling the role of hepcidin in iron homeostasis, however, such studies still report hepcidin mRNA levels as a surrogate marker for bioactive hepcidin in its pivotal function to block ferroportin-mediated iron transport. Here, we aimed to assess bioactive mouse Hepcidin-1 (Hep-1 and its paralogue Hepcidin-2 (Hep-2 at the peptide level. To this purpose, Fourier transform ion cyclotron resonance (FTICR and tandem-MS was used for hepcidin identification, after which a time-of-flight (TOF MS-based methodology was exploited to routinely determine Hep-1 and -2 levels in mouse serum and urine. This method was biologically validated by hepcidin assessment in: i 3 mouse strains (C57Bl/6; DBA/2 and BABL/c upon stimulation with intravenous iron and LPS, ii homozygous Hfe knock out, homozygous transferrin receptor 2 (Y245X mutated mice and double affected mice, and iii mice treated with a sublethal hepatotoxic dose of paracetamol. The results showed that detection of Hep-1 was restricted to serum, whereas Hep-2 and its presumed isoforms were predominantly present in urine. Elevations in serum Hep-1 and urine Hep-2 upon intravenous iron or LPS were only moderate and varied considerably between mouse strains. Serum Hep-1 was decreased in all three hemochromatosis models, being lowest in the double affected mice. Serum Hep-1 levels correlated with liver hepcidin-1 gene expression, while acute liver damage by paracetamol depleted Hep-1 from serum. Furthermore, serum Hep-1 appeared to be an excellent indicator of splenic iron accumulation. In conclusion, Hep-1 and Hep-2 peptide responses in experimental mouse agree with the known biology of hepcidin mRNA regulators, and their measurement can now be implemented in experimental mouse models to provide novel insights in post-transcriptional regulation, hepcidin function, and kinetics.

Relaxations in spin glasses: Similarities and differences from ordinary glasses

International Nuclear Information System (INIS)

Ngai, K.L.; Rajagopal, A.K.; Huang, C.Y.

1984-01-01

Relaxation phenomena have become a major concern in the physics of spin glasses. There are certain resemblances of these relaxation properties to those of ordinary glasses. In this work, we compare the relaxation properties of spin glasses near the freezing temperature with those of glasses near the glass transition temperature. There are similarities between the two types of glasses. Moreover, the relaxation properties of many glasses and spin glasses are in conformity with two coupled ''universality'' relations predicted by a recent model of relaxations in condensed matter

Incorporation of defects into the central atoms model of a metallic glass

International Nuclear Information System (INIS)

Lass, Eric A.; Zhu Aiwu; Shiflet, G.J.; Joseph Poon, S.

2011-01-01

The central atoms model (CAM) of a metallic glass is extended to incorporate thermodynamically stable defects, similar to vacancies in a crystalline solid, within the amorphous structure. A bond deficiency (BD), which is the proposed defect present in all metallic glasses, is introduced into the CAM equations. Like vacancies in a crystalline solid, BDs are thermodynamically stable entities because of the increase in entropy associated with their creation, and there is an equilibrium concentration present in the glassy phase. When applied to Cu-Zr and Ni-Zr binary metallic glasses, the concentration of thermally induced BDs surrounding Zr atoms reaches a relatively constant value at the glass transition temperature, regardless of composition within a given glass system. Using this 'critical' defect concentration, the predicted temperatures at which the glass transition is expected to occur are in good agreement with the experimentally determined glass transition temperatures for both alloy systems.

Glass science tutorial: Lecture No. 7, Waste glass technology for Hanford

International Nuclear Information System (INIS)

Kruger, A.A.

1995-07-01

This paper presents the details of the waste glass tutorial session that was held to promote knowledge of waste glass technology and how this can be used at the Hanford Reservation. Topics discussed include: glass properties; statistical approach to glass development; processing properties of nuclear waste glass; glass composition and the effects of composition on durability; model comparisons of free energy of hydration; LLW glass structure; glass crystallization; amorphous phase separation; corrosion of refractories and electrodes in waste glass melters; and glass formulation for maximum waste loading

Mouse Models as Predictors of Human Responses: Evolutionary Medicine.

Science.gov (United States)

Uhl, Elizabeth W; Warner, Natalie J

Mice offer a number of advantages and are extensively used to model human diseases and drug responses. Selective breeding and genetic manipulation of mice have made many different genotypes and phenotypes available for research. However, in many cases, mouse models have failed to be predictive. Important sources of the prediction problem have been the failure to consider the evolutionary basis for species differences, especially in drug metabolism, and disease definitions that do not reflect the complexity of gene expression underlying disease phenotypes. Incorporating evolutionary insights into mouse models allow for unique opportunities to characterize the effects of diet, different gene expression profiles, and microbiomics underlying human drug responses and disease phenotypes.

An approach to thermochemical modeling of nuclear waste glass

International Nuclear Information System (INIS)

Besmann, T.M.; Beahm, E.C.; Spear, K.E.

1998-01-01

This initial work is aimed at developing a basic understanding of the phase equilibria and solid solution behavior of the constituents of waste glass. Current, experimentally determined values are less than desirable since they depend on measurement of the leach rate under non-realistic conditions designed to accelerate processes that occur on a geologic time scale. The often-used assumption that the activity of a species is either unity or equal to the overall concentration of the metal can also yield misleading results. The associate species model, a recent development in thermochemical modeling, will be applied to these systems to more accurately predict chemical activities in such complex systems as waste glasses

Quantitative model of super-Arrhenian behavior in glass forming materials

Science.gov (United States)

Caruthers, J. M.; Medvedev, G. A.

2018-05-01

The key feature of glass forming liquids is the super-Arrhenian temperature dependence of the mobility, where the mobility can increase by ten orders of magnitude or more as the temperature is decreased if crystallization does not intervene. A fundamental description of the super-Arrhenian behavior has been developed; specifically, the logarithm of the relaxation time is a linear function of 1 /U¯x , where U¯x is the independently determined excess molar internal energy and B is a material constant. This one-parameter mobility model quantitatively describes data for 21 glass forming materials, which are all the materials where there are sufficient experimental data for analysis. The effect of pressure on the loga mobility is also described using the same U¯x(T ,p ) function determined from the difference between the liquid and crystalline internal energies. It is also shown that B is well correlated with the heat of fusion. The prediction of the B /U¯x model is compared to the Adam and Gibbs 1 /T S¯x model, where the B /U¯x model is significantly better in unifying the full complement of mobility data. The implications of the B /U¯x model for the development of a fundamental description of glass are discussed.

An acceptance model for smart glasses based tourism augmented reality

Science.gov (United States)

Obeidy, Waqas Khalid; Arshad, Haslina; Huang, Jiung Yao

2017-10-01

Recent mobile technologies have revolutionized the way people experience their environment. Although, there is only limited research on users' acceptance of AR in the cultural tourism context, previous researchers have explored the opportunities of using augmented reality (AR) in order to enhance user experience. Recent AR research lack works that integrates dimensions which are specific to cultural tourism and smart glass specific context. Hence, this work proposes an AR acceptance model in the context of cultural heritage tourism and smart glasses capable of performing augmented reality. Therefore, in this paper we aim to present an AR acceptance model to understand the AR usage behavior and visiting intention for tourists who use Smart Glass based AR at UNESCO cultural heritage destinations in Malaysia. Furthermore, this paper identifies information quality, technology readiness, visual appeal, and facilitating conditions as external variables and key factors influencing visitors' beliefs, attitudes and usage intention.

Mouse models for gastric cancer: Matching models to biological questions

Science.gov (United States)

Poh, Ashleigh R; O'Donoghue, Robert J J

2016-01-01

Abstract Gastric cancer is the third leading cause of cancer‐related mortality worldwide. This is in part due to the asymptomatic nature of the disease, which often results in late‐stage diagnosis, at which point there are limited treatment options. Even when treated successfully, gastric cancer patients have a high risk of tumor recurrence and acquired drug resistance. It is vital to gain a better understanding of the molecular mechanisms underlying gastric cancer pathogenesis to facilitate the design of new‐targeted therapies that may improve patient survival. A number of chemically and genetically engineered mouse models of gastric cancer have provided significant insight into the contribution of genetic and environmental factors to disease onset and progression. This review outlines the strengths and limitations of current mouse models of gastric cancer and their relevance to the pre‐clinical development of new therapeutics. PMID:26809278

Glass Transition Temperature of Saccharide Aqueous Solutions Estimated with the Free Volume/Percolation Model.

Science.gov (United States)

Constantin, Julian Gelman; Schneider, Matthias; Corti, Horacio R

2016-06-09

The glass transition temperature of trehalose, sucrose, glucose, and fructose aqueous solutions has been predicted as a function of the water content by using the free volume/percolation model (FVPM). This model only requires the molar volume of water in the liquid and supercooled regimes, the molar volumes of the hypothetical pure liquid sugars at temperatures below their pure glass transition temperatures, and the molar volumes of the mixtures at the glass transition temperature. The model is simplified by assuming that the excess thermal expansion coefficient is negligible for saccharide-water mixtures, and this ideal FVPM becomes identical to the Gordon-Taylor model. It was found that the behavior of the water molar volume in trehalose-water mixtures at low temperatures can be obtained by assuming that the FVPM holds for this mixture. The temperature dependence of the water molar volume in the supercooled region of interest seems to be compatible with the recent hypothesis on the existence of two structure of liquid water, being the high density liquid water the state of water in the sugar solutions. The idealized FVPM describes the measured glass transition temperature of sucrose, glucose, and fructose aqueous solutions, with much better accuracy than both the Gordon-Taylor model based on an empirical kGT constant dependent on the saccharide glass transition temperature and the Couchman-Karasz model using experimental heat capacity changes of the components at the glass transition temperature. Thus, FVPM seems to be an excellent tool to predict the glass transition temperature of other aqueous saccharides and polyols solutions by resorting to volumetric information easily available.

A kinetic model for borosilicate glass dissolution based on the dissolution affinity of a surface alteration layer

International Nuclear Information System (INIS)

Bourcier, W.L.; Peiffer, D.W.; Knauss, K.G.; McKeegan, K.D.; Smith, D.K.

1989-11-01

A kinetic model for the dissolution of borosilicate glass is used to predict the dissolution rate of a nuclear waste glass. In the model, the glass dissolution rate is controlled by the rate of dissolution of an alkali-depleted amorphous surface (gel) layer. Our model predicts that all components concentrated in the surface layer, affect glass dissolution rates. The good agreement between predicted and observed elemental dissolution rates suggests that the dissolution rate of the gel layer limits the overall rate of glass dissolution. The model predicts that the long-term rate of glass dissolution will depend mainly on ion concentrations in solution, and therefore on the secondary phases which precipitate and control ion concentrations. 10 refs., 5 figs., 1 tab

Histologic scoring of gastritis and gastric cancer in mouse models.

Science.gov (United States)

Rogers, Arlin B

2012-01-01

Histopathology is a defining endpoint in mouse models of experimental gastritis and gastric adenocarcinoma. Presented here is an overview of the histology of gastritis and gastric cancer in mice experimentally infected with Helicobacter pylori or H. felis. A modular histopathologic scoring scheme is provided that incorporates relevant disease-associated changes. Whereas the guide uses Helicobacter infection as the prototype challenge, features may be applied to chemical and genetically engineered mouse models of stomach cancer as well. Specific criteria included in the combined gastric histologic activity index (HAI) include inflammation, epithelial defects, oxyntic atrophy, hyperplasia, pseudopyloric metaplasia, and dysplasia or neoplasia. Representative photomicrographs accompany descriptions for each lesion grade. Differentiation of genuine tumor invasion from pseudoinvasion is highlighted. A brief comparison of normal rodent versus human stomach anatomy and physiology is accompanied by an introduction to mouse-specific lesions including mucous metaplasia and eosinophilic droplets (hyalinosis). In conjunction with qualified pathology support, this guide is intended to assist research scientists, postdoctoral fellows, graduate students, and medical professionals from affiliated disciplines in the interpretation and histologic grading of chronic gastritis and gastric carcinoma in mouse models.

Heat Transfer Model of a Small-Scale Waste Glass Melter with Cold Cap Layer

Energy Technology Data Exchange (ETDEWEB)

Abboud, Alexander; Guillen, Donna Post; Pokorny, Richard

2016-09-01

At the Hanford site in the state of Washington, more than 56 million gallons of radioactive waste is stored in underground tanks. The cleanup plan for this waste is vitrification at the Waste Treatment Plant (WTP), currently under construction. At the WTP, the waste will be blended with glass-forming materials and heated to 1423K, then poured into stainless steel canisters to cool and solidify. A fundamental understanding of the glass batch melting process is needed to optimize the process to reduce cost and decrease the life cycle of the cleanup effort. The cold cap layer that floats on the surface of the glass melt is the primary reaction zone for the feed-to-glass conversion. The conversion reactions include water release, melting of salts, evolution of batch gases, dissolution of quartz and the formation of molten glass. Obtaining efficient heat transfer to this region is crucial to achieving high rates of glass conversion. Computational fluid dynamics (CFD) modeling is being used to understand the heat transfer dynamics of the system and provide insight to optimize the process. A CFD model was developed to simulate the DM1200, a pilot-scale melter that has been extensively tested by the Vitreous State Laboratory (VSL). Electrodes are built into the melter to provide Joule heating to the molten glass. To promote heat transfer from the molten glass into the reactive cold cap layer, bubbling of the molten glass is used to stimulate forced convection within the melt pool. A three-phase volume of fluid approach is utilized to model the system, wherein the molten glass and cold cap regions are modeled as separate liquid phases, and the bubbling gas and plenum regions are modeled as one lumped gas phase. The modeling of the entire system with a volume of fluid model allows for the prescription of physical properties on a per-phase basis. The molten glass phase and the gas phase physical properties are obtained from previous experimental work. Finding representative

Precision Glass Molding: Validation of an FE Model for Thermo-Mechanical Simulation

DEFF Research Database (Denmark)

Sarhadi, Ali; Hattel, Jesper Henri; Hansen, Hans Nørgaard

2014-01-01

glass molding process including heating, pressing, and cooling stages. Temperature- dependent viscoelastic and structural relaxation behavior of the glass material are implemented through a FORTRAN material subroutine (UMAT) into the commercial FEM program ABAQUS, and the FE model is validated...

Development of a Representative Mouse Model with Nonalcoholic Steatohepatitis.

Science.gov (United States)

Verbeek, Jef; Jacobs, Ans; Spincemaille, Pieter; Cassiman, David

2016-06-01

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease in the Western world. It represents a disease spectrum ranging from isolated steatosis to non-alcoholic steatohepatitis (NASH). In particular, NASH can evolve to fibrosis, cirrhosis, hepatocellular carcinoma, and liver failure. The development of novel treatment strategies is hampered by the lack of representative NASH mouse models. Here, we describe a NASH mouse model, which is based on feeding non-genetically manipulated C57BL6/J mice a 'Western style' high-fat/high-sucrose diet (HF-HSD). HF-HSD leads to early obesity, insulin resistance, and hypercholesterolemia. After 12 weeks of HF-HSD, all mice exhibit the complete spectrum of features of NASH, including steatosis, hepatocyte ballooning, and lobular inflammation, together with fibrosis in the majority of mice. Hence, this model closely mimics the human disease. Implementation of this mouse model will lead to a standardized setup for the evaluation of (i) underlying mechanisms that contribute to the progression of NAFLD to NASH, and (ii) therapeutic interventions for NASH. © 2016 by John Wiley & Sons, Inc. Copyright © 2016 John Wiley & Sons, Inc.

Integrated modelling of the glass-iron-clay system

International Nuclear Information System (INIS)

Bildstein, O.

2007-01-01

This report summarizes the results of integrated calculations on the near-field evolution in the VHLW/steel/bentonite/clay system. The calculations of the near-field evolution include different components: the vitrified waste packages, the steel container, the bentonite-based EBS (optional), the EDZ and the geological medium. Coupled reaction-transport (X-T) is used to simulate the corrosion of the steel canister and the glass alteration phase in presence of corrosion products (CPs), looking at mass transfer for chemical elements, especially iron and silica, pH, and porosity change. Calculations as performed give actual parameters for PA calculations: rate of glass alteration (through the calculated pH) as a function of time, extension of altered zone for iron-clay interactions with their own transport parameters, nature of CPs, effect on porosity distribution. According to the operational model currently used at the CEA and the calculations performed on the glass-iron-clay system, the alteration rate of glass and the evolution of the system strongly depend on the timing of CPs saturation with respect to silica sorption. The fate of silica which can be sorbed or precipitate is crucial to the lifetime of glass and to the overall evolution of the system. The other process that might influence the glass is the porosity decrease due to the precipitation of CPs and silica rich phases. However, it is difficult to assign a safety functions to clogging. It is scarcely observed in experiments, either because the conditions are not met for clogging or because the timescale of experiments does not allow for observable clogging. Moreover, the effect of mechanical stress in the NF has to be accounted for in the assessment of the effect of porosity changes. (author)

Integrated modelling of the glass-iron-clay system

Energy Technology Data Exchange (ETDEWEB)

Bildstein, O

2007-01-15

This report summarizes the results of integrated calculations on the near-field evolution in the VHLW/steel/bentonite/clay system. The calculations of the near-field evolution include different components: the vitrified waste packages, the steel container, the bentonite-based EBS (optional), the EDZ and the geological medium. Coupled reaction-transport (X-T) is used to simulate the corrosion of the steel canister and the glass alteration phase in presence of corrosion products (CPs), looking at mass transfer for chemical elements, especially iron and silica, pH, and porosity change. Calculations as performed give actual parameters for PA calculations: rate of glass alteration (through the calculated pH) as a function of time, extension of altered zone for iron-clay interactions with their own transport parameters, nature of CPs, effect on porosity distribution. According to the operational model currently used at the CEA and the calculations performed on the glass-iron-clay system, the alteration rate of glass and the evolution of the system strongly depend on the timing of CPs saturation with respect to silica sorption. The fate of silica which can be sorbed or precipitate is crucial to the lifetime of glass and to the overall evolution of the system. The other process that might influence the glass is the porosity decrease due to the precipitation of CPs and silica rich phases. However, it is difficult to assign a safety functions to clogging. It is scarcely observed in experiments, either because the conditions are not met for clogging or because the timescale of experiments does not allow for observable clogging. Moreover, the effect of mechanical stress in the NF has to be accounted for in the assessment of the effect of porosity changes. (author)

Anticonvulsant profile of a balanced ketogenic diet in acute mouse seizure models.

Science.gov (United States)

Samala, Ramakrishna; Willis, Sarah; Borges, Karin

2008-10-01

Anticonvulsant effects of the ketogenic diet (KD) have been reported in the mouse, although previous studies did not control for intake of vitamins, minerals and antioxidants. The aim of this study was to examine the effects of balanced ketogenic and control diets in acute mouse seizure models. The behavior in four mouse seizure models, plasma d-beta-hydroxybutyrate (d-BHB) and glucose levels were determined after feeding control diet, 4:1 and 6:1 KDs with matched vitamins, minerals and antioxidants. Feeding 4:1 and 6:1 KDs ad lib to 3-week-old (adolescent) mice resulted in 1.2-2.2mM d-BHB in plasma, but did not consistently change glucose levels. The 6:1 KD reproducibly elevated the CC50 (current that initiates seizures in 50% mice tested) in the 6-Hz model after 14 days of feeding to adolescent CD1 mice. Higher plasma d-BHB levels correlated with anticonvulsant effects. Despite ketosis, no consistent anticonvulsant effects of KDs were found in the fluorothyl or pentylenetetrazole CD1 mouse models. The 4:1 KD was neither anticonvulsant nor neuroprotective in hippocampus in the C3H mouse kainate model. Taken together, the KD's anticonvulsant effect was limited to the 6-Hz model, required chronic feeding with 6:1 fat content, and was independent from lowering plasma glucose.

Long-term behavior of nuclear glass: the r(t) operational model

International Nuclear Information System (INIS)

Ribet, I.; Gin, S.; Minet, Y.; Vernaz, E.; Chaix, P.; Do Quang, R.

2001-01-01

Predicting the long-term behavior of vitrified waste packages requires the development of models incorporating knowledge of the aqueous alteration mechanisms of nuclear glass. The r(t) model allows for the formation of a protective gel layer during leaching, and is thus able to account for the major drops in the glass alteration rate that are observed experimentally. This article describes the model hypotheses, the methodology implemented to determine its three internal parameters, and the results obtained from about fifty leaching experiments performed under various conditions. The orders of magnitude of the internal parameter values are indicated according to the alteration conditions. (author)

The STR/ort mouse model of spontaneous osteoarthritis - an update.

Science.gov (United States)

Staines, K A; Poulet, B; Wentworth, D N; Pitsillides, A A

2017-06-01

Osteoarthritis is a degenerative joint disease and a world-wide healthcare burden. Characterized by cartilage degradation, subchondral bone thickening and osteophyte formation, osteoarthritis inflicts much pain and suffering, for which there are currently no disease-modifying treatments available. Mouse models of osteoarthritis are proving critical in advancing our understanding of the underpinning molecular mechanisms. The STR/ort mouse is a well-recognized model which develops a natural form of osteoarthritis very similar to the human disease. In this Review we discuss the use of the STR/ort mouse in understanding this multifactorial disease with an emphasis on recent advances in its genetics and its bone, endochondral and immune phenotypes. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Numerical study of the glass-glass transition in short-ranged attractive colloids

International Nuclear Information System (INIS)

Zaccarelli, Emanuela; Sciortino, Francesco; Tartaglia, Piero

2004-01-01

We report extensive numerical simulations in the glass region for a simple model of short-ranged attractive colloids, the square well model. We investigate the behaviour of the density autocorrelation function and of the static structure factor in the region of temperatures and packing fractions where a glass-glass transition is expected according to theoretical predictions. We strengthen our observations by studying both waiting time and history dependence of the numerical results. We provide evidence supporting the possibility that activated bond-breaking processes destabilize the attractive glass, preventing the full observation of a sharp glass-glass kinetic transition

Decerebrate mouse model for studies of the spinal cord circuits

DEFF Research Database (Denmark)

Meehan, Claire Francesca; Mayr, Kyle A; Manuel, Marin

2017-01-01

The adult decerebrate mouse model (a mouse with the cerebrum removed) enables the study of sensory-motor integration and motor output from the spinal cord for several hours without compromising these functions with anesthesia. For example, the decerebrate mouse is ideal for examining locomotor be......, which is ample time to perform most short-term procedures. These protocols can be modified for those interested in cardiovascular or respiratory function in addition to motor function and can be performed by trainees with some previous experience in animal surgery....

Chemical analysis of simulated high level waste glasses to support stage III sulfate solubility modeling

Energy Technology Data Exchange (ETDEWEB)

Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-03-17

The U.S. Department of Energy (DOE), Office of Environmental Management (EM) is sponsoring an international, collaborative project to develop a fundamental model for sulfate solubility in nuclear waste glass. The solubility of sulfate has a significant impact on the achievable waste loading for nuclear waste forms within the DOE complex. These wastes can contain relatively high concentrations of sulfate, which has low solubility in borosilicate glass. This is a significant issue for low-activity waste (LAW) glass and is projected to have a major impact on the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Sulfate solubility has also been a limiting factor for recent high level waste (HLW) sludge processed at the Savannah River Site (SRS) Defense Waste Processing Facility (DWPF). The low solubility of sulfate in glass, along with melter and off-gas corrosion constraints, dictate that the waste be blended with lower sulfate concentration waste sources or washed to remove sulfate prior to vitrification. The development of enhanced borosilicate glass compositions with improved sulfate solubility will allow for higher waste loadings and accelerate mission completion.The objective of the current scope being pursued by SHU is to mature the sulfate solubility model to the point where it can be used to guide glass composition development for DWPF and WTP, allowing for enhanced waste loadings and waste throughput at these facilities. A series of targeted glass compositions was selected to resolve data gaps in the model and is identified as Stage III. SHU fabricated these glasses and sent samples to SRNL for chemical composition analysis. SHU will use the resulting data to enhance the sulfate solubility model and resolve any deficiencies. In this report, SRNL provides chemical analyses for the Stage III, simulated HLW glasses fabricated by SHU in support of the sulfate solubility model development.

Thermal stability of the French nuclear waste glass - long term behavior modeling

International Nuclear Information System (INIS)

Orlhac, X.

2000-01-01

The thermal stability of the French nuclear waste glass was investigated experimentally and by modeling to predict its long-term evolution at low temperature. The crystallization mechanisms were analyzed by studying devitrification in the supercooled liquid. Three main crystalline phases were characterized (CaMoO 4 , CeCO 2 , ZnCr 2 O 4 ). Their crystallisation was TO 4.24 wt%, due to the low concentration of the constituent elements. The nucleation and growth curves showed that platinoid elements catalysed nucleation but did not affect growth, which was governed by volume diffusion. The criteria of classic nucleation theory were applied to determine the thermodynamic and diffusional activation energies. Viscosity measurements illustrate the analogy between the activation energy of viscous flow and diffusion, indicating control of crystallization by viscous flow phenomena. The combined action of nucleation and growth was assessed by TTT plots, revealing a crystallization equilibrium line that enables the crystallized fractions to be predicted over the long term. The authors show that hetero-genetics catalyze the transformation without modifying the maximum crystallized fraction. A kinetic model was developed to describe devitrification in the glass based on the nucleation and growth curves alone. The authors show that the low-temperature growth exhibits scale behavior (between time and temperature) similar to thermo-rheological simplicity. The analogy between the resulting activation energy and that of the viscosity was used to model growth on the basis of viscosity. After validation with a simplified (BaO 2 SiO 2 ) glass, the model was applied to the containment glass. The result indicated that the glass remained completely vitreous after a cooling scenario with the one measured at the glass core. Under isothermal conditions, several million years would be required to reach the maximum theoretical crystallization fraction. (author)

Predictive modeling of crystal accumulation in high-level waste glass melters processing radioactive waste

Science.gov (United States)

Matyáš, Josef; Gervasio, Vivianaluxa; Sannoh, Sulaiman E.; Kruger, Albert A.

2017-11-01

The effectiveness of high-level waste vitrification at Hanford's Waste Treatment and Immobilization Plant may be limited by precipitation/accumulation of spinel crystals [(Fe, Ni, Mn, Zn)(Fe, Cr)2O4] in the glass discharge riser of Joule-heated ceramic melters during idling. These crystals do not affect glass durability; however, if accumulated in thick layers, they can clog the melter and prevent discharge of molten glass into canisters. To address this problem, an empirical model was developed that can predict thicknesses of accumulated layers as a function of glass composition. This model predicts well the accumulation of single crystals and/or small-scale agglomerates, but excessive agglomeration observed in high-Ni-Fe glass resulted in an underprediction of accumulated layers, which gradually worsened over time as an increased number of agglomerates formed. The accumulation rate of ∼53.8 ± 3.7 μm/h determined for this glass will result in a ∼26 mm-thick layer after 20 days of melter idling.

Predictive modeling of crystal accumulation in high-level waste glass melters processing radioactive waste

Energy Technology Data Exchange (ETDEWEB)

Matyáš, Josef; Gervasio, Vivianaluxa; Sannoh, Sulaiman E.; Kruger, Albert A.

2017-11-01

The effectiveness of HLW vitrification is limited by precipitation/accumulation of spinel crystals [(Fe, Ni, Mn, Zn)(Fe, Cr)2O4] in the glass discharge riser of Joule-heated ceramic melters during idling. These crystals do not affect glass durability; however, if accumulated in thick layer, they can clog the melter and prevent discharge of molten glass into canisters. To address this problem, an empirical model was developed that can predict thicknesses of accumulated layers as a function of glass composition. This model predicts well the accumulation of single crystals and/or small-scale agglomerates, but, excessive agglomeration observed in high-Ni-Fe glass resulted in an under-prediction of accumulated layers, which gradually worsen over time as an increased number of agglomerates formed. Accumulation rate of ~53.8 ± 3.7 µm/h determined for this glass will result in ~26 mm thick layer in 20 days of melter idling.

The Event Coordination Notation: Behaviour Modelling Beyond Mickey Mouse

DEFF Research Database (Denmark)

Jepsen, Jesper; Kindler, Ekkart

2015-01-01

The Event Coordination Notation (ECNO) allows modelling the desired behaviour of a software system on top of any object-oriented software. Together with existing technologies from Model-based Software Engineering (MBSE) for automatically generating the software for the structural parts, ECNO allows...... special aspect of ECNO or another; and it would be fair to call them “Mickey Mouse examples”. In this paper, we give a concise overview of the motivation, ideas, and concepts of ECNO. More importantly, we discuss a larger system, which was completely generated from the underlying models: a workflow...... management system. This way, we demonstrate that ECNO can be used for modelling software beyond the typical Mickey Mouse examples. This example demonstrates that the essence of workflow management – including its behaviour – can be captured in ECNO: in a sense, it is a domain model of workflow management...

Determination of heat conductivity of waste glass feed and its applicability for modeling the batch-to-glass conversion

Czech Academy of Sciences Publication Activity Database

Hujová, Miroslava; Pokorný, R.; Kloužek, Jaroslav; Dixon, D.R.; Cutforth, D.A.; Lee, S.; McCarthy, B.P.; Schweiger, M. J.; Kruger, A.A.; Hrma, P.

2017-01-01

Roč. 100, č. 11 (2017), s. 5096-5106 ISSN 0002-7820 Institutional support: RVO:67985891 Keywords : foams * glassmelting * modelling/model * thermal conductivity Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass OBOR OECD: Ceramics Impact factor: 2.841, year: 2016

Towards optimization of nuclear waste glass: Constraints, property models, and waste loading

International Nuclear Information System (INIS)

Hrma, P.

1994-04-01

Vitrification of both low- and high-level wastes from 177 tanks at Hanford poses a great challenge to glass makers, whose task is to formulate a system of glasses that are acceptable to the federal repository for disposal. The enormous quantity of the waste requires a glass product of the lowest possible volume. The incomplete knowledge of waste composition, its variability, and lack of an appropriate vitrification technology further complicates this difficult task. A simple relationship between the waste loading and the waste glass volume is presented and applied to the predominantly refractory (usually high-activity) and predominantly alkaline (usually low-activity) waste types. Three factors that limit waste loading are discussed, namely product acceptability, melter processing, and model validity. Glass formulation and optimization problems are identified and a broader approach to uncertainties is suggested

Glass and vitrification

International Nuclear Information System (INIS)

Barton, J.L.; Vacher, R.; Moncouyoux, J.P.; Vernaz, E.

1997-01-01

Most glasses used as materials are oxides glasses that are produced by a quick quench of a liquid. Glasses are characterized by the absence of periodicity in the atomic arrangements, they do not have symmetries and do not present order over a long distance. This series of 4 short articles present: 1) the properties of glass and its industrial story, 2) the glass structure, 3) a forty years long story of glass as dies used to confine wastes and 4) the methodology used to study the behaviour of glass over very long periods of time. This methodology is based on 5 steps: 1) define and specify the material to study (the prediction of long term alteration of a material is nonsense unless you know well its initial properties), 2) identify all the alteration processes that are likely to happen, determine their kinetics and the influence of environmental parameters, 3) develop mathematical models in order to simulate long-term behaviour of glasses, 4) determine the release rates of the radionuclides confined in the glass, and 5) validate data and models, it is not possible to expect a complete validation of a model that will be extrapolated over tens of thousands of years, nevertheless some ways of validation can lead to a satisfactory level of confidence taking into account reasonable uncertainties. (A.C.)

Effects of glass composition on the residual rate of alteration and modelling parameters

International Nuclear Information System (INIS)

Fleury, Benjamin

2013-01-01

This PhD thesis deals with the long-term behavior of the French nuclear glasses R7T7. An experiment plan (based on 27 glass compositions) is developed for studying the effect of glass composition on the residual rate of alteration. The impact of Mg-phase precipitation on glass alteration is also studied and several modelling exercises are performed. There is one order of magnitude between the different measurements (rate or pH...) associated with the different glass compositions. The statistical treatment of these measurements results in predictive equations and several observable trends are valid for all materials with a composition complying with the experiment plan conditions. The effect of Si, Na, B and Al on alteration (.i.e, gel and secondary phase's formation, pH) is confirmed, the influence of Zn, Zr and Ni-Co is evidenced. The role of Cr has to be clarified. Experiments show that glass alteration rate in underground water, which contains high level of Ca and Mg, is one order of magnitude higher than in the case of pure water. The glass composition plays the same role for the alteration in the two types of solution. During alteration, the late addition of Mg introduces a time lag in the resumption response because silicon is first provided from partial dissolution of the previously-formed alteration gel. The nucleation process does not limit Mg-silicate precipitation whereas a pH above 8-8.5 is necessary for Mg-silicate precipitation. The glass alteration rate can be a limiting factor if the quantity of Mg supplied to the reaction is enough. The Mg silicate phase seems to have systematically a molar ratio Mg/Si between 0.2 and 0.4. It is also shown that the air tightness of the reactor influences the rate of dissolution of CO 2 in the solution leading to a decrease of pH. Finally, modelling exercises with GRAAL show promising results. Such modelling is required in order to extend the prediction of the long-term alteration behavior to different glass

Thermodynamic and structural models compared with the initial dissolution rates of SON glass samples

International Nuclear Information System (INIS)

Tovena, I.; Advocat, T.; Ghaleb, D.; Vernaz, E.

1993-01-01

The experimentally determined initial dissolution rate R 0 of nuclear glass was correlated with thermodynamic parameters and structural parameters. The initial corrosion rates of six ''R7T7'' glass samples measured at 100 deg C in a Soxhlet device were correlated with the glass free hydration energy and the glass formation enthalpy. These correlations were then tested with a group of 26 SON glasses selected for their wide diversity of compositions. The thermodynamic models provided a satisfactory approximation of the initial dissolution rate determined under Soxhlet conditions for SON glass samples that include up to 15 wt% of boron and some alumina. Conversely, these models are inaccurate if the boron concentration exceeds 15 wt% and the glass contains no alumina. Possible correlations between R 0 and structural parameters, such as the boron coordination number and the number of nonbridging oxygen atoms, were also investigated. The authors show that R 0 varies inversely with the number of 4-coordinate boron atoms; conversely, the results do not substantiate published reports of a correlation between R 0 and the number of nonbridging oxygen atoms. (authors). 13 refs., 2 figs., 4 tabs

Modeling the Losses of Dissolved CO(2) from Laser-Etched Champagne Glasses.

Science.gov (United States)

Liger-Belair, Gérard

2016-04-21

Under standard champagne tasting conditions, the complex interplay between the level of dissolved CO2 found in champagne, its temperature, the glass shape, and the bubbling rate definitely impacts champagne tasting by modifying the neuro-physicochemical mechanisms responsible for aroma release and flavor perception. On the basis of theoretical principles combining heterogeneous bubble nucleation, ascending bubble dynamics, and mass transfer equations, a global model is proposed, depending on various parameters of both the wine and the glass itself, which quantitatively provides the progressive losses of dissolved CO2 from laser-etched champagne glasses. The question of champagne temperature was closely examined, and its role on the modeled losses of dissolved CO2 was corroborated by a set of experimental data.

Pathology of Mouse Models of Accelerated Aging

NARCIS (Netherlands)

Harkema, L.; Youssef, S. A.; de Bruin, A.

Progeroid mouse models display phenotypes in multiple organ systems that suggest premature aging and resemble features of natural aging of both mice and humans. The prospect of a significant increase in the global elderly population within the next decades has led to the emergence of geroscience,

Pathology of Mouse Models of Accelerated Aging

NARCIS (Netherlands)

Harkema, L; Youssef, S A; de Bruin, A

2016-01-01

Progeroid mouse models display phenotypes in multiple organ systems that suggest premature aging and resemble features of natural aging of both mice and humans. The prospect of a significant increase in the global elderly population within the next decades has led to the emergence of "geroscience,"

Correlation between acoustical and structural properties of glasses: Extension of Abd El-Moneim model for bioactive silica based glasses

Energy Technology Data Exchange (ETDEWEB)

Abd El-Moneim, Amin, E-mail: aminabdelmoneim@hotmail.com

2016-04-15

Correlation between room temperature ultrasonic attenuation coefficient and the most significant structural parameters has been studied in the bioactive silica based glasses, for the first time. The correlation has been carried out in the quaternary SiO{sub 2}–Na{sub 2}O–CaO–P{sub 2}O{sub 5} glass system using the two semi-empirical formulas, which have been presented recently by the author. Changes in the elastic properties, related to the substitution of SiO{sub 2} by alkali Na{sub 2}O and alkaline earth CaO oxides, have also been deduced by evaluating the mean atomic volume, packing density, fractal bond connectivity and density of the analogous crystalline structure. Furthermore, values of the theoretical elastic moduli have been calculated on the basis of Makishima-Mackenzie theory and compared with the corresponding observed values. Results show that the correlation between ultrasonic attenuation coefficient and the oxygen density, average atomic ring size, first-order stretching force constant and experimental bulk modulus was achieved at 5 MHz frequency. Values of the theoretically calculated shear modulus are in excellent correlation (C. R. ≻95%) with the corresponding experimental ones. The divergence between the theoretical and experimental values of bulk modulus has been discussed. - Highlights: • Abd El-Moneim model was extended for bioactive glasses. • Ultrasonic attenuation was correlated with structural parameters. • Correlation was carried out in Si–Na–Ca–P glasses. • The model is valid for all investigated glass samples. • Agreement between theoretical and experimental elastic moduli was studied.

Kinetic model for quartz and spinel dissolution during melting of high-level-waste glass batch

International Nuclear Information System (INIS)

Pokorny, Richard; Rice, Jarrett A.; Crum, Jarrod V.; Schweiger, Michael J.; Hrma, Pavel

2013-01-01

The dissolution of quartz particles and the growth and dissolution of crystalline phases during the conversion of batch to glass potentially affects both the glass melting process and product quality. Crystals of spinel exiting the cold cap to molten glass below can be troublesome during the vitrification of iron-containing high-level wastes. To estimate the distribution of quartz and spinel fractions within the cold cap, we used kinetic models that relate fractions of these phases to temperature and heating rate. Fitting the model equations to data showed that the heating rate, apart from affecting quartz and spinel behavior directly, also affects them indirectly via concurrent processes, such as the formation and motion of bubbles. Because of these indirect effects, it was necessary to allow one kinetic parameter (the pre-exponential factor) to vary with the heating rate. The resulting kinetic equations are sufficiently simple for the detailed modeling of batch-to-glass conversion as it occurs in glass melters. The estimated fractions and sizes of quartz and spinel particles as they leave the cold cap, determined in this study, will provide the source terms needed for modeling the behavior of these solid particles within the flow of molten glass in the melter

Genome-Wide Expression Profiling of Five Mouse Models Identifies Similarities and Differences with Human Psoriasis

Science.gov (United States)

Swindell, William R.; Johnston, Andrew; Carbajal, Steve; Han, Gangwen; Wohn, Christian; Lu, Jun; Xing, Xianying; Nair, Rajan P.; Voorhees, John J.; Elder, James T.; Wang, Xiao-Jing; Sano, Shigetoshi; Prens, Errol P.; DiGiovanni, John; Pittelkow, Mark R.; Ward, Nicole L.; Gudjonsson, Johann E.

2011-01-01

Development of a suitable mouse model would facilitate the investigation of pathomechanisms underlying human psoriasis and would also assist in development of therapeutic treatments. However, while many psoriasis mouse models have been proposed, no single model recapitulates all features of the human disease, and standardized validation criteria for psoriasis mouse models have not been widely applied. In this study, whole-genome transcriptional profiling is used to compare gene expression patterns manifested by human psoriatic skin lesions with those that occur in five psoriasis mouse models (K5-Tie2, imiquimod, K14-AREG, K5-Stat3C and K5-TGFbeta1). While the cutaneous gene expression profiles associated with each mouse phenotype exhibited statistically significant similarity to the expression profile of psoriasis in humans, each model displayed distinctive sets of similarities and differences in comparison to human psoriasis. For all five models, correspondence to the human disease was strong with respect to genes involved in epidermal development and keratinization. Immune and inflammation-associated gene expression, in contrast, was more variable between models as compared to the human disease. These findings support the value of all five models as research tools, each with identifiable areas of convergence to and divergence from the human disease. Additionally, the approach used in this paper provides an objective and quantitative method for evaluation of proposed mouse models of psoriasis, which can be strategically applied in future studies to score strengths of mouse phenotypes relative to specific aspects of human psoriasis. PMID:21483750

Analytical and regression models of glass rod drawing process

Science.gov (United States)

Alekseeva, L. B.

2018-03-01

The process of drawing glass rods (light guides) is being studied. The parameters of the process affecting the quality of the light guide have been determined. To solve the problem, mathematical models based on general equations of continuum mechanics are used. The conditions for the stable flow of the drawing process have been found, which are determined by the stability of the motion of the glass mass in the formation zone to small uncontrolled perturbations. The sensitivity of the formation zone to perturbations of the drawing speed and viscosity is estimated. Experimental models of the drawing process, based on the regression analysis methods, have been obtained. These models make it possible to customize a specific production process to obtain light guides of the required quality. They allow one to find the optimum combination of process parameters in the chosen area and to determine the required accuracy of maintaining them at a specified level.

Heat transfer modelling in thermophotovoltaic cavities using glass media

Energy Technology Data Exchange (ETDEWEB)

Bauer, T.; Forbes, I.; Penlington, R.; Pearsall, N. [Northumbria University, Newcastle upon Tyne (United Kingdom). School of Engineering and Technology

2005-08-15

Optimisation of heat transfer, and in particular radiative heat transfer in terms of the spectral, angular and spatial radiation distributions, is required to achieve high efficiencies and high electrical power densities for thermophotovoltaic (TPV) conversion. This work examines heat transfer from the radiator to the PV cell in an infinite plate arrangement using three different arrangements of participating dielectric media. The modelling applies the Discrete Ordinates method and assumes fused silica (quartz glass) as the dielectric medium. The arrangement radiator-glass-PV cell (also termed dielectric photon concentration) was found to be superior in terms of efficiency and power density. (author)

An inducible mouse model of late onset Tay-Sachs disease.

Science.gov (United States)

Jeyakumar, Mylvaganam; Smith, David; Eliott-Smith, Elena; Cortina-Borja, Mario; Reinkensmeier, Gabriele; Butters, Terry D; Lemm, Thorsten; Sandhoff, Konrad; Perry, V Hugh; Dwek, Raymond A; Platt, Frances M

2002-08-01

Mouse models of the G(M2) gangliosidoses, Tay-Sachs and Sandhoff disease, are null for the hexosaminidase alpha and beta subunits respectively. The Sandhoff (Hexb-/-) mouse has severe neurological disease and mimics the human infantile onset variant. However, the Tay-Sachs (Hexa-/-) mouse model lacks an overt phenotype as mice can partially bypass the blocked catabolic pathway and escape disease. We have investigated whether a subset of Tay-Sachs mice develop late onset disease. We have found that approximately 65% of the mice develop one or more clinical signs of the disease within their natural life span (n = 52, P disease at an earlier age (n = 21, P Tay-Sachs mice confirmed that pregnancy induces late onset Tay-Sachs disease. Onset of symptoms correlated with reduced up-regulation of hexosaminidase B, a component of the bypass pathway.

Ultrastructural study of Rift Valley fever virus in the mouse model

Energy Technology Data Exchange (ETDEWEB)

Reed, Christopher; Steele, Keith E.; Honko, Anna; Shamblin, Joshua; Hensley, Lisa E. [United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, MD (United States); Smith, Darci R., E-mail: darci.smith1@us.army.mil [United States Army Medical Research Institute of Infectious Diseases (USAMRIID), Fort Detrick, MD (United States)

2012-09-15

Detailed ultrastructural studies of Rift Valley fever virus (RVFV) in the mouse model are needed to develop and characterize a small animal model of RVF for the evaluation of potential vaccines and therapeutics. In this study, the ultrastructural features of RVFV infection in the mouse model were analyzed. The main changes in the liver included the presence of viral particles in hepatocytes and hepatic stem cells accompanied by hepatocyte apoptosis. However, viral particles were observed rarely in the liver; in contrast, particles were extremely abundant in the CNS. Despite extensive lymphocytolysis, direct evidence of viral replication was not observed in the lymphoid tissue. These results correlate with the acute-onset hepatitis and delayed-onset encephalitis that are dominant features of severe human RVF, but suggest that host immune-mediated mechanisms contribute significantly to pathology. The results of this study expand our knowledge of RVFV-host interactions and further characterize the mouse model of RVF.

Ultrastructural study of Rift Valley fever virus in the mouse model

International Nuclear Information System (INIS)

Reed, Christopher; Steele, Keith E.; Honko, Anna; Shamblin, Joshua; Hensley, Lisa E.; Smith, Darci R.

2012-01-01

Detailed ultrastructural studies of Rift Valley fever virus (RVFV) in the mouse model are needed to develop and characterize a small animal model of RVF for the evaluation of potential vaccines and therapeutics. In this study, the ultrastructural features of RVFV infection in the mouse model were analyzed. The main changes in the liver included the presence of viral particles in hepatocytes and hepatic stem cells accompanied by hepatocyte apoptosis. However, viral particles were observed rarely in the liver; in contrast, particles were extremely abundant in the CNS. Despite extensive lymphocytolysis, direct evidence of viral replication was not observed in the lymphoid tissue. These results correlate with the acute-onset hepatitis and delayed-onset encephalitis that are dominant features of severe human RVF, but suggest that host immune-mediated mechanisms contribute significantly to pathology. The results of this study expand our knowledge of RVFV–host interactions and further characterize the mouse model of RVF.

Engineering a new mouse model for vitiligo.

Science.gov (United States)

Manga, Prashiela; Orlow, Seth J

2012-07-01

Although the precise mechanisms that trigger vitiligo remain elusive, autoimmune responses mediate its progression. The development of therapies has been impeded by a paucity of animal models, since mice lack interfollicular melanocytes, the primary targets in vitiligo. In this issue, Harris et al. describe a mouse model in which interfollicular melanocytes are retained by Kit ligand overexpression and an immune response is initiated by transplanting melanocyte-targeting CD8+ T cells.

Taltirelin alleviates fatigue-like behavior in mouse models of cancer-related fatigue.

Science.gov (United States)

Dougherty, John P; Wolff, Brian S; Cullen, Mary J; Saligan, Leorey N; Gershengorn, Marvin C

2017-10-01

Fatigue affects most cancer patients and has numerous potential causes, including cancer itself and cancer treatment. Cancer-related fatigue (CRF) is not relieved by rest, can decrease quality of life, and has no FDA-approved therapy. Thyrotropin-releasing hormone (TRH) has been proposed as a potential novel treatment for CRF, but its efficacy against CRF remains largely untested. Thus, we tested the TRH analog, taltirelin (TAL), in mouse models of CRF. To model fatigue, we used a mouse model of chemotherapy, a mouse model of radiation therapy, and mice bearing colon 26 carcinoma tumors. We used the treadmill fatigue test to assess fatigue-like behavior after treatment with TAL. Additionally, we used wild-type and TRH receptor knockout mice to determine which TRH receptor was necessary for the actions of TAL. Tumor-bearing mice displayed muscle wasting and all models caused fatigue-like behavior, with mice running a shorter distance in the treadmill fatigue test than controls. TAL reversed fatigue-like behavior in all three models and the mouse TRH 1 receptor was necessary for the effects of TAL. These data suggest that TAL may be useful in alleviating fatigue in all cancer patients and provide further support for evaluating TAL as a potential therapy for CRF in humans. Published by Elsevier Ltd.

Low frequency elastic properties of glasses at low temperatures - implications on the tunneling model

International Nuclear Information System (INIS)

Raychaudhuri, A.K.; Hunklinger, S.

1984-01-01

We have measured the low frequency elastic properties of dielectric, normal conducting and superconducting metallic glasses at audio-frequencies (fapprox.=1 kHz) and temperatures down to 10 mK. Our results are discussed in the framework of the tunneling model of glasses. The major assumption of the tunneling model regarding the tunneling states with long relaxation time has been verified, but discrepancies to high frequency measurements have been found. In addition, our experiments on superconducting metallic glasses seem to indicate that the present treatment of the electron-tunneling state interaction is not sufficient. (orig.)

Cardiac disease and arrhythmogenesis: Mechanistic insights from mouse models

Directory of Open Access Journals (Sweden)

Lois Choy

2016-09-01

Full Text Available The mouse is the second mammalian species, after the human, in which substantial amount of the genomic information has been analyzed. With advances in transgenic technology, mutagenesis is now much easier to carry out in mice. Consequently, an increasing number of transgenic mouse systems have been generated for the study of cardiac arrhythmias in ion channelopathies and cardiomyopathies. Mouse hearts are also amenable to physical manipulation such as coronary artery ligation and transverse aortic constriction to induce heart failure, radiofrequency ablation of the AV node to model complete AV block and even implantation of a miniature pacemaker to induce cardiac dyssynchrony. Last but not least, pharmacological models, despite being simplistic, have enabled us to understand the physiological mechanisms of arrhythmias and evaluate the anti-arrhythmic properties of experimental agents, such as gap junction modulators, that may be exert therapeutic effects in other cardiac diseases. In this article, we examine these in turn, demonstrating that primary inherited arrhythmic syndromes are now recognized to be more complex than abnormality in a particular ion channel, involving alterations in gene expression and structural remodelling. Conversely, in cardiomyopathies and heart failure, mutations in ion channels and proteins have been identified as underlying causes, and electrophysiological remodelling are recognized pathological features. Transgenic techniques causing mutagenesis in mice are extremely powerful in dissecting the relative contributions of different genes play in producing disease phenotypes. Mouse models can serve as useful systems in which to explore how protein defects contribute to arrhythmias and direct future therapy.

Olfaction in three genetic and two MPTP-induced Parkinson's disease mouse models.

Directory of Open Access Journals (Sweden)

Stefan Kurtenbach

Full Text Available Various genetic or toxin-induced mouse models are frequently used for investigation of early PD pathology. Although olfactory impairment is known to precede motor symptoms by years, it is not known whether it is caused by impairments in the brain, the olfactory epithelium, or both. In this study, we investigated the olfactory function in three genetic Parkinson's disease (PD mouse models and mice treated with MPTP intraperitoneally and intranasally. To investigate olfactory function, we performed electro-olfactogram recordings (EOGs and an olfactory behavior test (cookie-finding test. We show that neither a parkin knockout mouse strain, nor intraperitoneal MPTP treated animals display any olfactory impairment in EOG recordings and the applied behavior test. We also found no difference in the responses of the olfactory epithelium to odorants in a mouse strain over-expressing doubly mutated α-synuclein, while this mouse strain was not suitable to test olfaction in a cookie-finding test as it displays a mobility impairment. A transgenic mouse expressing mutated α-synuclein in dopaminergic neurons performed equal to control animals in the cookie-finding test. Further we show that intranasal MPTP application can cause functional damage of the olfactory epithelium.

Spin glasses

CERN Document Server

Bovier, Anton

2007-01-01

Spin glass theory is going through a stunning period of progress while finding exciting new applications in areas beyond theoretical physics, in particular in combinatorics and computer science. This collection of state-of-the-art review papers written by leading experts in the field covers the topic from a wide variety of angles. The topics covered are mean field spin glasses, including a pedagogical account of Talagrand's proof of the Parisi solution, short range spin glasses, emphasizing the open problem of the relevance of the mean-field theory for lattice models, and the dynamics of spin glasses, in particular the problem of ageing in mean field models. The book will serve as a concise introduction to the state of the art of spin glass theory, usefull to both graduate students and young researchers, as well as to anyone curious to know what is going on in this exciting area of mathematical physics.

Quantitative trait loci affecting phenotypic variation in the vacuolated lens mouse mutant, a multigenic mouse model of neural tube defects

NARCIS (Netherlands)

Korstanje, Ron; Desai, Jigar; Lazar, Gloria; King, Benjamin; Rollins, Jarod; Spurr, Melissa; Joseph, Jamie; Kadambi, Sindhuja; Li, Yang; Cherry, Allison; Matteson, Paul G.; Paigen, Beverly; Millonig, James H.

Korstanje R, Desai J, Lazar G, King B, Rollins J, Spurr M, Joseph J, Kadambi S, Li Y, Cherry A, Matteson PG, Paigen B, Millonig JH. Quantitative trait loci affecting phenotypic variation in the vacuolated lens mouse mutant, a multigenic mouse model of neural tube defects. Physiol Genomics 35:

LIQUIDUS TEMPERATURE AND ONE PERCENT CRYSTAL CONTENT MODELS FOR INITIAL HANFORD HLW GLASSES

International Nuclear Information System (INIS)

Vienna, John D.; Edwards, Tommy B.; Crum, Jarrod V.; Kim, Dong-Sang; Peeler, David K.

2005-01-01

Preliminary models for liquidus temperature (TL) and temperature at 1 vol% crystal (T01) applicable to WTP HLW glasses in the spinel primary phase field were developed. A series of literature model forms were evaluated using consistent sets of data form model fitting and validation. For TL, the ion potential and linear mixture models performed best, while for T01 the linear mixture model out performed all other model forms. TL models were able to predict with smaller uncertainty. However, the lower T01 values (even with higher prediction uncertainties) were found to allow for a much broader processing envelope for WTP HLW glasses

Nonspecific airway reactivity in a mouse model of asthma

Energy Technology Data Exchange (ETDEWEB)

Collie, D.D.; Wilder, J.A.; Bice, D.E.

1995-12-01

Animal models are indispensable for studies requiring an intact immune system, especially for studying the pathogenic mechanisms in atopic diseases, regulation of IgE production, and related biologic effects. Mice are particularly suitable and have been used extensively for such studies because their immune system is well characterized. Further, large numbers of mutants or inbred strains of mice are available that express deficiencies of individual immunologic processes, inflammatory cells, or mediator systems. By comparing reactions in such mice with appropriate control animals, the unique roles of individual cells or mediators may be characterized more precisely in the pathogenesis of atopic respiratory diseases including asthma. However, given that asthma in humans is characterized by the presence of airway hyperresponsiveness to specific and nonspecific stimuli, it is important that animal models of this disease exhibit similar physiologic abnormalities. In the past, the size of the mouse has limited its versatility in this regard. However, recent studies indicate the feasibility of measuring pulmonary responses in living mice, thus facilitating the physiologic evaluation of putative mouse models of human asthma that have been well charcterized at the immunologic and patholigic level. Future work will provide details of the morphometry of the methacholine-induced bronchoconstriction and will further seek to determine the relationship between cigarette smoke exposure and the development of NS-AHR in the transgenic mouse model.

Mouse Models Recapitulating Human Adrenocortical Tumors: What is lacking?

Directory of Open Access Journals (Sweden)

Felicia Leccia

2016-07-01

Full Text Available Adrenal cortex tumors are divided into benign forms such as primary hyperplasias and adrenocortical adenomas (ACAs, and malignant forms or adrenocortical carcinomas (ACCs. Primary hyperplasias are rare causes of ACTH-independent hypercortisolism. ACAs are the most common type of adrenal gland tumors and they are rarely functional, i.e producing steroids. When functional, adenomas result in endocrine disorders such as Cushing’s syndrome (hypercortisolism or Conn’s syndrome (hyperaldosteronism. In contrast, ACCs are extremely rare but highly aggressive tumors that may also lead to hypersecreting syndromes. Genetic analyses of patients with sporadic or familial forms of adrenocortical tumors led to the identification of potentially causative genes, most of them being involved in PKA, Wnt/β-catenin and P53 signaling pathways. Development of mouse models is a crucial step to firmly establish the functional significance of candidate genes, to dissect mechanisms leading to tumors and endocrine disorders and in fine to provide in vivo tools for therapeutic screens. In this article we will provide an overview on the existing mouse models (xenografted and genetically engineered of adrenocortical tumors by focusing on the role of PKA and Wnt/β-catenin pathways in this context. We will discuss the advantages and limitations of models that have been developed heretofore and we will point out necessary improvements in the development of next generation mouse models of adrenal diseases.

Spallanzani's mouse: a model of restoration and regeneration.

Science.gov (United States)

Heber-Katz, E; Leferovich, J M; Bedelbaeva, K; Gourevitch, D

2004-01-01

The ability to regenerate is thought to be a lost phenotype in mammals, though there are certainly sporadic examples of mammalian regeneration. Our laboratory has identified a strain of mouse, the MRL mouse, which has a unique capacity to heal complex tissue in an epimorphic fashion, i.e., to restore a damaged limb or organ to its normal structure and function. Initial studies using through-and-through ear punches showed rapid full closure of the ear holes with cartilage growth, new hair follicles, and normal tissue architecture reminiscent of regeneration seen in amphibians as opposed to the scarring usually seen in mammals. Since the ear hole closure phenotype is a quantitative trait, this has been used to show-through extensive breeding and backcrossing--that the trait is heritable. Such analysis reveals that there is a complex genetic basis for this trait with multiple loci. One of the major phenotypes of the MRL mouse is a potent remodeling response with the absence or a reduced level of scarring. MRL healing is associated with the upregulation of the metalloproteinases MMP-2 and MMP-9 and the downregulation of their inhibitors TIMP-2 and TIMP-3, both present in inflammatory cells such as neutrophils and macrophages. This model has more recently been extended to the heart. In this case, a cryoinjury to the right ventricle leads to near complete scarless healing in the MRL mouse whereas scarring is seen in the control mouse. In the MRL heart, bromodeoxyuridine uptake by cardiomyocytes filling the wound site can be seen 60 days after injury. This does not occur in the control mouse. Function in the MRL heart, as measured by echocardiography, returns to normal.

A chimeric human-mouse model of Sjögren's syndrome.

Science.gov (United States)

Young, Nicholas A; Wu, Lai-Chu; Bruss, Michael; Kaffenberger, Benjamin H; Hampton, Jeffrey; Bolon, Brad; Jarjour, Wael N

2015-01-01

Despite recent advances in the understanding of Sjögren's Syndrome (SjS), the pathogenic mechanisms remain elusive and an ideal model for early drug discovery is not yet available. To establish a humanized mouse model of SjS, peripheral blood mononuclear cells (PBMCs) from healthy volunteers or patients with SjS were transferred into immunodeficient NOD-scid IL-2rγ(null) mouse recipients to produce chimeric mice. While no difference was observed in the distribution of cells, chimeric mice transferred with PBMCs from SjS patients produced enhanced cytokine levels, most significantly IFN-γ and IL-10. Histological examination revealed enhanced inflammatory responses in the lacrimal and salivary glands of SjS chimeras, as measured by digital image analysis and blinded histopathological scoring. Infiltrates were primarily CD4+, with minimal detection of CD8+ T-cells and B-cells. These results demonstrate a novel chimeric mouse model of human SjS that provides a unique in vivo environment to test experimental therapeutics and investigate T-cell disease pathology. Copyright © 2014. Published by Elsevier Inc.

A novel approach to modelling non-exponential spin glass relaxation

Energy Technology Data Exchange (ETDEWEB)

Pickup, R.M. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom)]. E-mail: r.cywinski@leeds.ac.uk; Cywinski, R. [School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT (United Kingdom); Pappas, C. [Hahn-Meitner Institut, Glienicker Strasse 100, 14109 Berlin (Germany)

2007-07-15

A probabilistic cluster model, originally proposed by Weron to explain the universal power law of dielectric relaxation, is shown to account for the non-exponential relaxation in spin glasses above T {sub g}. Neutron spin echo spectra measured for the cluster glass compound Co{sub 55}Ga{sub 45} are well described by the Weron relaxation function, {phi}(t)={phi} {sub o}(1+k(t/{tau}) {sup {beta}}){sup -1/k}, with the interaction parameter k scaling linearly with the non-Curie-Weiss susceptibility.

Are the dynamics of silicate glasses and glass-forming liquids embedded in their elastic properties?

DEFF Research Database (Denmark)

Smedskjær, Morten Mattrup; Mauro, John C.

According to the elastic theory of the glass transition, the dynamics of glasses and glass-forming liquids are controlled by the evolution of shear modulus. In particular, the elastic shoving model expresses dynamics in terms of an activation energy required to shove aside the surrounding atoms......, which is determined by the shear modulus. First, we here present an in situ high-temperature Brillouin spectroscopy test of the shoving model near the glass transition of eight aluminosilicate glass-forming systems. We find that the measured viscosity data agree qualitatively with the measured...... temperature dependence of shear moduli, as predicted by the shoving model. However, the model systematically underpredicts the values of fragility. Second, we also present a thorough test of the shoving model for predicting the low temperature dynamics of an aluminosilicate glass system. This is done...

Rapid genetic algorithm optimization of a mouse computational model: Benefits for anthropomorphization of neonatal mouse cardiomyocytes

Directory of Open Access Journals (Sweden)

Corina Teodora Bot

2012-11-01

Full Text Available While the mouse presents an invaluable experimental model organism in biology, its usefulness in cardiac arrhythmia research is limited in some aspects due to major electrophysiological differences between murine and human action potentials (APs. As previously described, these species-specific traits can be partly overcome by application of a cell-type transforming clamp (CTC to anthropomorphize the murine cardiac AP. CTC is a hybrid experimental-computational dynamic clamp technique, in which a computationally calculated time-dependent current is inserted into a cell in real time, to compensate for the differences between sarcolemmal currents of that cell (e.g., murine and the desired species (e.g., human. For effective CTC performance, mismatch between the measured cell and a mathematical model used to mimic the measured AP must be minimal. We have developed a genetic algorithm (GA approach that rapidly tunes a mathematical model to reproduce the AP of the murine cardiac myocyte under study. Compared to a prior implementation that used a template-based model selection approach, we show that GA optimization to a cell-specific model results in a much better recapitulation of the desired AP morphology with CTC. This improvement was more pronounced when anthropomorphizing neonatal mouse cardiomyocytes to human-like APs than to guinea pig APs. CTC may be useful for a wide range of applications, from screening effects of pharmaceutical compounds on ion channel activity, to exploring variations in the mouse or human genome. Rapid GA optimization of a cell-specific mathematical model improves CTC performance and may therefore expand the applicability and usage of the CTC technique.

DEFENSE HIGH LEVEL WASTE GLASS DEGRADATION

International Nuclear Information System (INIS)

Ebert, W.

2001-01-01

The purpose of this Analysis/Model Report (AMR) is to document the analyses that were done to develop models for radionuclide release from high-level waste (HLW) glass dissolution that can be integrated into performance assessment (PA) calculations conducted to support site recommendation and license application for the Yucca Mountain site. This report was developed in accordance with the ''Technical Work Plan for Waste Form Degradation Process Model Report for SR'' (CRWMS M andO 2000a). It specifically addresses the item, ''Defense High Level Waste Glass Degradation'', of the product technical work plan. The AP-3.15Q Attachment 1 screening criteria determines the importance for its intended use of the HLW glass model derived herein to be in the category ''Other Factors for the Postclosure Safety Case-Waste Form Performance'', and thus indicates that this factor does not contribute significantly to the postclosure safety strategy. Because the release of radionuclides from the glass will depend on the prior dissolution of the glass, the dissolution rate of the glass imposes an upper bound on the radionuclide release rate. The approach taken to provide a bound for the radionuclide release is to develop models that can be used to calculate the dissolution rate of waste glass when contacted by water in the disposal site. The release rate of a particular radionuclide can then be calculated by multiplying the glass dissolution rate by the mass fraction of that radionuclide in the glass and by the surface area of glass contacted by water. The scope includes consideration of the three modes by which water may contact waste glass in the disposal system: contact by humid air, dripping water, and immersion. The models for glass dissolution under these contact modes are all based on the rate expression for aqueous dissolution of borosilicate glasses. The mechanism and rate expression for aqueous dissolution are adequately understood; the analyses in this AMR were conducted to

A general model for the dissolution of nuclear waste glasses in salt brine

International Nuclear Information System (INIS)

McGrail, B.P.; Strachan, D.M.

1988-07-01

A mechanistic model describing a dynamic mass balance between the production and consumption of dissolved silica was found to describe the dissolution of SRL-165 defense waste glass in a high-magnesium (PBB3) brine at a temperature of 90/degree/C. The synergetic effect of the waste package container on the glass dissolution rate was found to depend on a precipitation reaction for a ferrous silicate mineral. The model predicted that the ferrous silicate precipitate should be variable in composition where the iron-silica ratio depended on the metal-to-glass surface area ratio used in the experiment. This prediction was confirmed experimentally by the variable iron-silica ratios observed in filtered leachates. However, the interaction between dissolved silica and iron corrosion products needs to be much better understood before the model could be used with confidence in predicting radionuclide release rates for a salt repository. If the deleterious effects of the iron corrosion products can be shown to be transient, and the fracturing of the glass can be minimized, it appears that the performance of SRL-165 defense waste glass will be near the NRC regulatory criterion for fraction release of one part in 100,000 in PBB3 brine at 90/degree/C under silica-saturated conditions. 47 refs., 6 figs., 1 tab

Combination radiotherapy in an orthotopic mouse brain tumor model.

Science.gov (United States)

Kramp, Tamalee R; Camphausen, Kevin

2012-03-06

Glioblastoma multiforme (GBM) are the most common and aggressive adult primary brain tumors. In recent years there has been substantial progress in the understanding of the mechanics of tumor invasion, and direct intracerebral inoculation of tumor provides the opportunity of observing the invasive process in a physiologically appropriate environment. As far as human brain tumors are concerned, the orthotopic models currently available are established either by stereotaxic injection of cell suspensions or implantation of a solid piece of tumor through a complicated craniotomy procedure. In our technique we harvest cells from tissue culture to create a cell suspension used to implant directly into the brain. The duration of the surgery is approximately 30 minutes, and as the mouse needs to be in a constant surgical plane, an injectable anesthetic is used. The mouse is placed in a stereotaxic jig made by Stoetling (figure 1). After the surgical area is cleaned and prepared, an incision is made; and the bregma is located to determine the location of the craniotomy. The location of the craniotomy is 2 mm to the right and 1 mm rostral to the bregma. The depth is 3 mm from the surface of the skull, and cells are injected at a rate of 2 μl every 2 minutes. The skin is sutured with 5-0 PDS, and the mouse is allowed to wake up on a heating pad. From our experience, depending on the cell line, treatment can take place from 7-10 days after surgery. Drug delivery is dependent on the drug composition. For radiation treatment the mice are anesthetized, and put into a custom made jig. Lead covers the mouse's body and exposes only the brain of the mouse. The study of tumorigenesis and the evaluation of new therapies for GBM require accurate and reproducible brain tumor animal models. Thus we use this orthotopic brain model to study the interaction of the microenvironment of the brain and the tumor, to test the effectiveness of different therapeutic agents with and without

Chemical composition analysis and product consistency tests to support Enhanced Hanford Waste Glass Models. Results for the Augusta and October 2014 LAW Glasses

Energy Technology Data Exchange (ETDEWEB)

Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Best, D. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-07-07

In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for several simulated low activity waste (LAW) glasses (designated as the August and October 2014 LAW glasses) fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation regions of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions.

Immunocompromised and immunocompetent mouse models for head and neck squamous cell carcinoma

Directory of Open Access Journals (Sweden)

Lei ZG

2016-01-01

Full Text Available Zhen-ge Lei,1,* Xiao-hua Ren,2,* Sha-sha Wang,3 Xin-hua Liang,3,4 Ya-ling Tang3,5 1Department of Oral and Maxillofacial Surgery, Stomatological Hospital Affiliated to Nanchang University, Nanchang, Jiangxi, 2Department of Stomatology, Sichuan Medical Science Academy and Sichuan Provincial People’s Hospital, 3State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, 4Department of Oral and Maxillofacial Surgery, West China College of Stomatology, Sichuan University, 5Department of Oral Pathology, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan, People’s Republic of China *These authors contributed equally to this work Abstract: Mouse models can closely mimic human oral squamous epithelial carcinogenesis, greatly expand the in vivo research possibilities, and play a critical role in the development of diagnosis, monitoring, and treatment of head and neck squamous cell carcinoma. With the development of the recent research on the contribution of immunity/inflammation to cancer initiation and progression, mouse models have been divided into two categories, namely, immunocompromised and immunocompetent mouse models. And thus, this paper will review these two kinds of models applied in head and neck squamous cell carcinoma to provide a platform to understand the complicated histological, molecular, and genetic changes of oral squamous epithelial tumorigenesis. Keywords: head and neck squamous cell carcinoma, HNSCC, mouse models, immunocompromised models, immunocompetent models, transgenic models

Measurements and modeling of gain coefficients for neodymium laser glasses

International Nuclear Information System (INIS)

Linford, G.J.; Saroyan, R.A.; Trenholme, J.B.; Weber, M.J.

1979-01-01

Small-signal gain coefficients are reported for neodymium in silicate, phosphate, fluorophosphate, and fluoroberyllate laser glasses. Measurements were made in a disk amplifier under identical conditions. Using spectroscopic data as the input, amplifier gain is calculated as a fucntion of flashlamp energy, pumping pulse duration, disk thickness, and Nd-doping. The agreement between predicted and measured gains is generally with ;plus or minus;10 percent, consistent with experimental uncertainties in the model and the parameters used. The operating conditions which optimize amplifier performance and efficiency for a given laser glass may be found using spectroscopic data alone. This process can be extended to derive the most cost-effective staging of amplifier chains for fusion lasers. A discussion of the model and examples of calculations are presented

ARRHENIUS MODEL FOR HIGH-TEMPERATURE GLASS VISCOSITY WITH A CONSTANT PRE-EXPONENTIAL FACTOR

International Nuclear Information System (INIS)

Hrma, Pavel R.

2008-01-01

A simplified form of the Arrhenius equation, ln η = A + B(x)/T, where η is the viscosity, T the temperature, x the composition vector, and A and B the Arrhenius coefficients, was fitted to glass-viscosity data for the processing temperature range (the range at which the viscosity is within 1 to 103 Pa.s) while setting A = constant and treating B(x) as a linear function of mass fractions of major components. Fitting the Arrhenius equation to over 550 viscosity data of commercial glasses and approximately 1000 viscosity data of glasses for nuclear-waste glasses resulted in the A values of -11.35 and -11.48, respectively. The R2 value ranged from 0.92 to 0.99 for commercial glasses and was 0.98 for waste glasses. The Arrhenius models estimate viscosities for melts of commercial glasses containing 42 to 84 mass% SiO2 within the temperature range of 1100 to 1550 C and viscosity range of 5 to 400 Pa.s and for waste glasses containing 32 to 60 mass% SiO2 within the temperature range of 850 to 1450 C and viscosity range of 0.4 to 250 Pa.s

Simplified model for a ventilated glass window under forced air flow conditions

International Nuclear Information System (INIS)

Ismail, K.A.R.; Henriquez, J.R.

2006-01-01

This paper presents a study on a ventilated window composed of two glass sheets separated by a spacing through which air is forced to flow. The proposed model is one dimensional and unsteady based upon global energy balance over the glass sheets and the flowing fluid. The external glass sheet of the cavity is subjected to variable heat flow due to the solar radiation as well as variable external ambient temperature. The exchange of radiation energy (infrared radiation) between the glass sheets is also included in the formulation. Effects of the spacing between the glass sheets, variation of the forced mass flow rate on the total heat gain and the shading coefficients are investigated. The results show that the effect of the increase of the mass flow rate is found to reduce the mean solar heat gain and the shading coefficients while the increase of the fluid entry temperature is found to deteriorate the window thermal performance

Simplified model for a ventilated glass window under forced air flow conditions

Energy Technology Data Exchange (ETDEWEB)

Ismail, K.A.R. [Depto. de Engenharia Termica e de Fluidos-FEM-UNICAMP CP: 6122 CEP 13083-970 Campinas, SP (Brazil); Henriquez, J.R. [Depto. de Eng. Mecanica-DEMEC, UFPE Av. Academico Helio Ramos, S/N CEP 50740-530, Recife, PE (Brazil)

2006-02-01

This paper presents a study on a ventilated window composed of two glass sheets separated by a spacing through which air is forced to flow. The proposed model is one dimensional and unsteady based upon global energy balance over the glass sheets and the flowing fluid. The external glass sheet of the cavity is subjected to variable heat flow due to the solar radiation as well as variable external ambient temperature. The exchange of radiation energy (infrared radiation) between the glass sheets is also included in the formulation. Effects of the spacing between the glass sheets, variation of the forced mass flow rate on the total heat gain and the shading coefficients are investigated. The results show that the effect of the increase of the mass flow rate is found to reduce the mean solar heat gain and the shading coefficients while the increase of the fluid entry temperature is found to deteriorate the window thermal performance. (author)

Centralized mouse repositories.

Science.gov (United States)

Donahue, Leah Rae; Hrabe de Angelis, Martin; Hagn, Michael; Franklin, Craig; Lloyd, K C Kent; Magnuson, Terry; McKerlie, Colin; Nakagata, Naomi; Obata, Yuichi; Read, Stuart; Wurst, Wolfgang; Hörlein, Andreas; Davisson, Muriel T

2012-10-01

Because the mouse is used so widely for biomedical research and the number of mouse models being generated is increasing rapidly, centralized repositories are essential if the valuable mouse strains and models that have been developed are to be securely preserved and fully exploited. Ensuring the ongoing availability of these mouse strains preserves the investment made in creating and characterizing them and creates a global resource of enormous value. The establishment of centralized mouse repositories around the world for distributing and archiving these resources has provided critical access to and preservation of these strains. This article describes the common and specialized activities provided by major mouse repositories around the world.

A Mouse Model for Human Anal Cancer

Science.gov (United States)

Stelzer, Marie K.; Pitot, Henry C.; Liem, Amy; Schweizer, Johannes; Mahoney, Charles; Lambert, Paul F.

2010-01-01

Human anal cancers are associated with high-risk human papillomaviruses (HPVs) that cause other anogenital cancers and head and neck cancers. As with other cancers, HPV16 is the most common high-risk HPV in anal cancers. We describe the generation and characterization of a mouse model for human anal cancer. This model makes use of K14E6 and K14E7 transgenic mice in which the HPV16 E6 and E7 genes are directed in their expression to stratified squamous epithelia. HPV16 E6 and E7 possess oncogenic properties including but not limited to their capacity to inactivate the cellular tumor suppressors p53 and pRb, respectively. Both E6 and E7 were found to be functionally expressed in the anal epithelia of K14E6/K14E7 transgenic mice. To assess the susceptibility of these mice to anal cancer, mice were treated topically with dimethylbenz[a]anthracene (DMBA), a chemical carcinogen that is known to induce squamous cell carcinomas in other sites. Nearly 50% of DMBA-treated HPV16 E6/E7 transgenic mice showed overt signs of tumors; whereas, none of the like treated non-transgenic mice showed tumors. Histopathological analyses confirmed that the HPV16 transgenic mice were increased in their susceptibility to anal cancers and precancerous lesions. Biomarker analyses demonstrated that these mouse anal cancers exhibit properties that are similar to those observed in HPV-positive precursors to human anal cancer. This is the first mouse model for investigating the contributions of viral and cellular factors in anal carcinogenesis, and should provide a platform for assessing new therapeutic modalities for treating and/or preventing this type of cancer. PMID:20947489

Kovacs effect in a model for a fragile glass

Science.gov (United States)

Aquino, Gerardo; Leuzzi, Luca; Nieuwenhuizen, Theo M.

2006-03-01

The Kovacs protocol, based on the temperature shift experiment originally conceived by A. J. Kovacs for glassy polymers, is implemented in an exactly solvable dynamical model. This model is characterized by interacting fast and slow modes represented, respectively, by spherical spins and harmonic oscillator variables. Due to this fundamental property, the model reproduces the characteristic nonmonotonic evolution known as the “Kovacs effect,” observed in polymers, spin glasses, granular materials, and molecular liquid models, when similar experimental protocols are implemented.

Use of molecular dynamics to model the structure of nuclear glasses

International Nuclear Information System (INIS)

Delaye, J.M.; Ghaleb, D.

1997-01-01

Born-Mayer-Huggins potentials (BMH) are generally used to model oxides glasses. In this article we show how they can be used, if they can be completed by three body terms, to reproduce correctly structures of alumino-borosilicate glasses. Taking into account the parameters adjusted for the basic matrix (SiO 2 , B 2 O 3 , Na 2 O, ZrO 2 , Al 2 O 3 ) of French light water reactor waste containment glass, we have analyzed equally the structure evolutions reproduced by BMH potentials according to the modification of the composition of the glass. The principal objective of this study being the appreciation of the capability of this potentials to simulate structure evolutions in the glass; this potentials representing neither the nature of chemical bonds nor the electronic state modifications that accompany changes of coordination numbers. Globally BHM potentials, despite their limited representativeness, reproduce some experimental observations. For example: - the gradual incorporation of the boron in the silicate network; - the shorter distances between network formers and non-bridging oxygen atoms; - the visualization of boron-enriched segregation zones in a high content boron composition without aluminum. (authors)

Physical modeling of joule heated ceramic glass melters for high level waste immobilization

International Nuclear Information System (INIS)

Quigley, M.S.; Kreid, D.K.

1979-03-01

This study developed physical modeling techniques and apparatus suitable for experimental analysis of joule heated ceramic glass melters designed for immobilizing high level waste. The physical modeling experiments can give qualitative insight into the design and operation of prototype furnaces and, if properly verified with prototype data, the physical models could be used for quantitative analysis of specific furnaces. Based on evaluation of the results of this study, it is recommended that the following actions and investigations be undertaken: It was not shown that the isothermal boundary conditions imposed by this study established prototypic heat losses through the boundaries of the model. Prototype wall temperatures and heat fluxes should be measured to provide better verification of the accuracy of the physical model. The VECTRA computer code is a two-dimensional analytical model. Physical model runs which are isothermal in the Y direction should be made to provide two-dimensional data for more direct comparison to the VECTRA predictions. The ability of the physical model to accurately predict prototype operating conditions should be proven before the model can become a reliable design tool. This will require significantly more prototype operating and glass property data than were available at the time of this study. A complete set of measurements covering power input, heat balances, wall temperatures, glass temperatures, and glass properties should be attempted for at least one prototype run. The information could be used to verify both physical and analytical models. Particle settling and/or sludge buildup should be studied directly by observing the accumulation of the appropriate size and density particles during feeding in the physical model. New designs should be formulated and modeled to minimize the potential problems with melter operation identifed by this study

NEW ERBIUM DOPED ANTIMONY GLASSES FOR LASER AND GLASS AMPLIFICATION

Directory of Open Access Journals (Sweden)

B. Tioua

2015-07-01

Full Text Available Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses. In this poster will offer new doped erbium glasses synthesized in silicate crucibles were obtained in the combination Sb2O3-WO3-Na2O. Several properties are measured and correlated with glass compositions. The absorption spectral studies have been performed for erbium doped glasses. The intensities of various absorption bands of the doped glasses are measured and the Judd-Ofelt parameters have been computed. From the theory of Judd-Ofelt, various radiative properties, such as transition probability, branching ratio and radiative life time for various emission levels of these doped glasses have been determined and reported. These results confirm the ability of antimony glasses for glass amplification.

Influence of Glass Property Restrictions on Hanford HLW Glass Volume

International Nuclear Information System (INIS)

Kim, Dong-Sang; Vienna, John D.

2001-01-01

A systematic evaluation of Hanford High-Level Waste (HLW) loading in alkali-alumino-borosilicate glasses was performed. The waste feed compositions used were obtained from current tank waste composition estimates, Hanford's baseline retrieval sequence, and pretreatment processes. The waste feeds were sorted into groups of like composition by cluster analysis. Glass composition optimization was performed on each cluster to meet property and composition constraints while maximizing waste loading. Glass properties were estimated using property models developed for Hanford HLW glasses. The impacts of many constraints on the volume of HLW glass to be produced at Hanford were evaluated. The liquidus temperature, melting temperature, chromium concentration, formation of multiple phases on cooling, and product consistency test response requirements for the glass were varied one- or many-at-a-time and the resultant glass volume was calculated. This study shows clearly that the allowance of crystalline phases in the glass melter can significantly decrease the volume of HLW glass to be produced at Hanford.

A consensus definition of cataplexy in mouse models of narcolepsy.

Science.gov (United States)

Scammell, Thomas E; Willie, Jon T; Guilleminault, Christian; Siegel, Jerome M

2009-01-01

People with narcolepsy often have episodes of cataplexy, brief periods of muscle weakness triggered by strong emotions. Many researchers are now studying mouse models of narcolepsy, but definitions of cataplexy-like behavior in mice differ across labs. To establish a common language, the International Working Group on Rodent Models of Narcolepsy reviewed the literature on cataplexy in people with narcolepsy and in dog and mouse models of narcolepsy and then developed a consensus definition of murine cataplexy. The group concluded that murine cataplexy is an abrupt episode of nuchal atonia lasting at least 10 seconds. In addition, theta activity dominates the EEG during the episode, and video recordings document immobility. To distinguish a cataplexy episode from REM sleep after a brief awakening, at least 40 seconds of wakefulness must precede the episode. Bouts of cataplexy fitting this definition are common in mice with disrupted orexin/hypocretin signaling, but these events almost never occur in wild type mice. It remains unclear whether murine cataplexy is triggered by strong emotions or whether mice remain conscious during the episodes as in people with narcolepsy. This working definition provides helpful insights into murine cataplexy and should allow objective and accurate comparisons of cataplexy in future studies using mouse models of narcolepsy.

Composition effects on chemical durability and viscosity of nuclear waste glasses - systematic studies and structural thermodynamic models

International Nuclear Information System (INIS)

Feng, X.

1988-01-01

Two of the primary criteria for the acceptability of nuclear waste glasses are their durability, i.e. chemical resistance to aqueous attack for 10 4 to 10 5 years, and processability, which requires their viscosity at the desired melt temperature to be sufficiently low. Chapter 3 presents the results of systematic composition variation studies around the preliminary reference glass composition WV205 and an atomistic interpretation of the effects of individual oxides. Chapter 4 is concerned with modifications of the Jantzen-Plodinec hydration model which takes into account formation of complex aluminosilicate compounds in the glass. Chapter 5 is devoted to the development and validation of the structural-thermodynamic model for both durability and viscosity. This model assumes the strength of bonds between atoms to be the controlling factor in the composition dependence of these glass properties. The binding strengths are derived from the known heats of formation and the structural roles of constituent oxides. Since the coordination state of various oxides in the glass is temperature dependent and cation size has opposite effects on the two properties, the correlation between melt viscosity and rate of corrosion at low temperature is not simply linear. Chapter 6 surveys the effects of aqueous phase composition on the leach behavior of glasses. These studies provide a comprehensive view of the effects of both glass composition and leachant composition on leaching. The models developed correlate both durability and viscosity with glass composition. A major implication is that these findings can be used in the systematic optimization of the properties of complex oxide glasses

Development of basic data for modelling the residual alteration rate in aqueous media of AVM nuclear glasses

International Nuclear Information System (INIS)

Thien, B.

2010-01-01

During their aqueous alteration, AVM French nuclear glasses exhibit a large range of behaviour, in spite of a small range of composition. AVM glasses alteration rates are controlled by two phenomena: (i) precipitation of secondary phases, mostly aluminous hectorites, and (ii) diffusion of water across a more or less protective gel. The magnesium contained in these glasses increases the precipitation of these secondary phases, leading to a partial or total dissolution of the gel layer. This dissolution increases the glass alteration rates. On the other hand, Mg also incorporates in the gel, increasing his passivation properties. The predominance of one of these two phenomena depends on the initial composition of the glass, the pH of the solution, and the alteration conditions. In presence of Bure geological disposal site water (Mg and Ca rich), AVM glasses undergo less alteration than in initially pure water, in spite of larger amounts of secondary phase precipitates. This results from incorporation of calcium in the gel instead of sodium and magnesium, improving its passivating properties. We have adapted the geochemical GRAAL model for AVM glasses. In spite of its limitations, this model allows us to describe the differences of behaviour between these glasses, in function of their composition. Moreover, GRAAL can be proposed as a basis of a future operational model for predicting the alteration of AVM glasses. (author) [fr

Development and function of human innate immune cells in a humanized mouse model.

Science.gov (United States)

Rongvaux, Anthony; Willinger, Tim; Martinek, Jan; Strowig, Till; Gearty, Sofia V; Teichmann, Lino L; Saito, Yasuyuki; Marches, Florentina; Halene, Stephanie; Palucka, A Karolina; Manz, Markus G; Flavell, Richard A

2014-04-01

Mice repopulated with human hematopoietic cells are a powerful tool for the study of human hematopoiesis and immune function in vivo. However, existing humanized mouse models cannot support development of human innate immune cells, including myeloid cells and natural killer (NK) cells. Here we describe two mouse strains called MITRG and MISTRG, in which human versions of four genes encoding cytokines important for innate immune cell development are knocked into their respective mouse loci. The human cytokines support the development and function of monocytes, macrophages and NK cells derived from human fetal liver or adult CD34(+) progenitor cells injected into the mice. Human macrophages infiltrated a human tumor xenograft in MITRG and MISTRG mice in a manner resembling that observed in tumors obtained from human patients. This humanized mouse model may be used to model the human immune system in scenarios of health and pathology, and may enable evaluation of therapeutic candidates in an in vivo setting relevant to human physiology.

Development of a transgenic mouse model to study the immunogenicity of recombinant human insulin

NARCIS (Netherlands)

Torosantucci, Riccardo; Brinks, Vera; Kijanka, Grzegorz; Halim, Liem Andhyk; Sauerborn, Melody; Schellekens, Huub; Jiskoot, Wim

2014-01-01

Mouse models are commonly used to assess the immunogenicity of therapeutic proteins and to investigate the immunological processes leading to antidrug antibodies. The aim of this work was to develop a transgenic (TG) Balb/c mouse model for evaluating the immunogenicity of recombinant human insulin

Conversion of Nuclear Waste into Nuclear Waste Glass: Experimental Investigation and Mathematical Modeling

International Nuclear Information System (INIS)

Hrma, Pavel

2014-01-01

The melter feed, slurry, or calcine charged on the top of a pool of molten glass forms a floating layer of reacting material called the cold cap. Between the cold-cap top, which is covered with boiling slurry, and its bottom, where bubbles separate it from molten glass, the temperature changes by up to 1000 K. The processes that occur over this temperature interval within the cold cap include liberation of gases, conduction and consumption of heat, dissolution of quartz particles, formation and dissolution of intermediate crystalline phases, and generation of foam and gas cavities. These processes have been investigated using thermal analyses, optical and electronic microscopies, x-ray diffraction, as well as other techniques. Properties of the reacting feed, such as heat conductivity and density, were measured as functions of temperature. Investigating the structure of quenched cold caps produced in a laboratory-scale melter complemented the crucible studies. The cold cap consists of two main layers. The top layer contains solid particles dissolving in the glass-forming melt and open pores through which gases are escaping. The bottom layer contains bubbly melt or foam where bubbles coalesce into larger cavities that move sideways and release the gas to the atmosphere. The feed-to-glass conversion became sufficiently understood for representing the cold-cap processes via mathematical models. These models, which comprise heat transfer, mass transfer, and reaction kinetics models, have been developed with the final goal to relate feed parameters to the rate of glass melting

Evaluation of synthetic vascular grafts in a mouse carotid grafting model.

Science.gov (United States)

Chan, Alex H P; Tan, Richard P; Michael, Praveesuda L; Lee, Bob S L; Vanags, Laura Z; Ng, Martin K C; Bursill, Christina A; Wise, Steven G

2017-01-01

Current animal models for the evaluation of synthetic grafts are lacking many of the molecular tools and transgenic studies available to other branches of biology. A mouse model of vascular grafting would allow for the study of molecular mechanisms of graft failure, including in the context of clinically relevant disease states. In this study, we comprehensively characterise a sutureless grafting model which facilitates the evaluation of synthetic grafts in the mouse carotid artery. Using conduits electrospun from polycaprolactone (PCL) we show the gradual development of a significant neointima within 28 days, found to be greatest at the anastomoses. Histological analysis showed temporal increases in smooth muscle cell and collagen content within the neointima, demonstrating its maturation. Endothelialisation of the PCL grafts, assessed by scanning electron microscopy (SEM) analysis and CD31 staining, was near complete within 28 days, together replicating two critical aspects of graft performance. To further demonstrate the potential of this mouse model, we used longitudinal non-invasive tracking of bone-marrow mononuclear cells from a transgenic mouse strain with a dual reporter construct encoding both luciferase and green fluorescent protein (GFP). This enabled characterisation of mononuclear cell homing and engraftment to PCL using bioluminescence imaging and histological staining over time (7, 14 and 28 days). We observed peak luminescence at 7 days post-graft implantation that persisted until sacrifice at 28 days. Collectively, we have established and characterised a high-throughput model of grafting that allows for the evaluation of key clinical drivers of graft performance.

Evaluation of synthetic vascular grafts in a mouse carotid grafting model.

Directory of Open Access Journals (Sweden)

Alex H P Chan

Full Text Available Current animal models for the evaluation of synthetic grafts are lacking many of the molecular tools and transgenic studies available to other branches of biology. A mouse model of vascular grafting would allow for the study of molecular mechanisms of graft failure, including in the context of clinically relevant disease states. In this study, we comprehensively characterise a sutureless grafting model which facilitates the evaluation of synthetic grafts in the mouse carotid artery. Using conduits electrospun from polycaprolactone (PCL we show the gradual development of a significant neointima within 28 days, found to be greatest at the anastomoses. Histological analysis showed temporal increases in smooth muscle cell and collagen content within the neointima, demonstrating its maturation. Endothelialisation of the PCL grafts, assessed by scanning electron microscopy (SEM analysis and CD31 staining, was near complete within 28 days, together replicating two critical aspects of graft performance. To further demonstrate the potential of this mouse model, we used longitudinal non-invasive tracking of bone-marrow mononuclear cells from a transgenic mouse strain with a dual reporter construct encoding both luciferase and green fluorescent protein (GFP. This enabled characterisation of mononuclear cell homing and engraftment to PCL using bioluminescence imaging and histological staining over time (7, 14 and 28 days. We observed peak luminescence at 7 days post-graft implantation that persisted until sacrifice at 28 days. Collectively, we have established and characterised a high-throughput model of grafting that allows for the evaluation of key clinical drivers of graft performance.

Spin Glass Models of Syntax and Language Evolution

OpenAIRE

Siva, Karthik; Tao, Jim; Marcolli, Matilde

2015-01-01

Using the SSWL database of syntactic parameters of world languages, and the MIT Media Lab data on language interactions, we construct a spin glass model of language evolution. We treat binary syntactic parameters as spin states, with languages as vertices of a graph, and assigned interaction energies along the edges. We study a rough model of syntax evolution, under the assumption that a strong interaction energy tends to cause parameters to align, as in the case of ferromagnetic materials. W...

Role of Stat in Skin Carcinogenesis: Insights Gained from Relevant Mouse Models

International Nuclear Information System (INIS)

Macias, E.; Rao, D.; DiGiovanni, J.; DiGiovanni, J.; DiGiovanni, J.

2013-01-01

Signal transducer and activator of transcription 3 (Stat) is a cytoplasmic protein that is activated in response to cytokines and growth factors and acts as a transcription factor. Stat plays critical roles in various biological activities including cell proliferation, migration, and survival. Studies using keratinocyte-specific Stat-deficient mice have revealed that Stat plays an important role in skin homeostasis including keratinocyte migration, wound healing, and hair follicle growth. Use of both constitutive and inducible keratinocyte-specific Stat-deficient mouse models has demonstrated that Stat is required for both the initiation and promotion stages of multistage skin carcinogenesis. Further studies using a transgenic mouse model with a gain of function mutant of Stat (Stat3C) expressed in the basal layer of the epidermis revealed a novel role for Stat in skin tumor progression. Studies using similar Stat-deficient and gain-of-function mouse models have indicated its similar roles in ultraviolet B (UVB) radiation-mediated skin carcinogenesis. This paper summarizes the use of these various mouse models for studying the role and underlying mechanisms for the function of Stat in skin carcinogenesis. Given its significant role throughout the skin carcinogenesis process, Stat is an attractive target for skin cancer prevention and treatment.

Understanding the effects of alpha self-irradiation on the glass structure by coupling spectroscopic studies and atomistic modeling

International Nuclear Information System (INIS)

Bureau, G.

2008-12-01

Our objective was to assess irradiation effects on nuclear containment glass in order to guarantee glass performance when subjected to high alpha decay doses. Experimental studies and molecular dynamics modeling provided a better understanding of the impact of cumulative alpha decay on the structural behavior of complex nuclear glass formulations and of simplified glass models. A mechanism typical of sodium borosilicate glass was identified in response to nuclear interactions or ballistic collisions. The glass local order is slightly modified by the conversion of a fraction of the boron atoms from coordination number IV to III, releasing charge-compensating alkali ions that become available as network modifiers, and resulting in a slight increase in the number of non bridging oxygen atoms. The medium-range order shifts toward increasing disorder in the glass as indicated by broadening of the angular, radial, and size distributions. A model of accumulated quasi-thermal quenching is proposed to account for these changes, based on the two steps describing the reaction of the glass to the alpha decay recoil nucleus: a cascade generates a ballistic phase that completely destabilizes the glass structure with no short and medium-range order, resulting in the loss of the initial structure; glass reconstruction is controlled only by the 'quenching rate' in the displacement cascade, i.e. by its thermal history and the corresponding relaxation options. From this standpoint the final glass structure is the consequence of the ballistic changes and the regenerative capacity of the glass structure, resulting in a higher fictive-temperature glass corresponding to the structural changes identified in this study. (author)

Light scattering in glass-ceramics

International Nuclear Information System (INIS)

Hendy, S.C.

2002-01-01

Full text: Glass-ceramic materials with microstructures comprised of dispersed nanocrystallites in a residual glass matrix show promise for many new technological applications. In particular, transparent glass-ceramics offer low thermal expansion and stability, in addition to the prospect of novel non-linear optical properties that can arise from the nanocrystallites. Good transparency requires low optical scattering and low atomic absorption. Light scattering in the glass-ceramic arises primarily from the glass-crystallite interface. The attenuation due to scattering (turbidity) will depend upon the difference in refractive index of the two phases and the size and distribution of nanocrystallites in the glass. Here we consider models of glass-ceramic structure formation and look at scattering in these model structures to increase our understanding of the transparency of glass-ceramics

Linking rigidity transitions with enthalpic changes at the glass transition and fragility: insight from a simple oscillator model.

Science.gov (United States)

Micoulaut, Matthieu

2010-07-21

A low temperature Monte Carlo dynamics of a Keating-like oscillator model is used to study the relationship between the nature of network glasses from the viewpoint of rigidity, the thermal reversibility during the glass transition and the strong-fragile behaviour of glass-forming liquids. The model shows that a Phillips optimal glass formation with minimal enthalpic changes is obtained under a cooling/annealing cycle when the system is optimally constrained by the harmonic interactions, i.e. when it is isostatically rigid. For these peculiar systems with a nearly reversible glass transition, the computed activation energy for relaxation time shows also a minimum, which demonstrates that isostatically rigid glasses are strong (Arrhenius-like) glass-forming liquids. Experiments on chalcogenide and oxide glass-forming liquids are discussed under this new perspective and confirm the theoretical prediction for chalcogenide network glasses whereas limitations of the approach appear for weakly interacting (non-covalent, ionic) systems.

The Perfect Glass Paradigm: Disordered Hyperuniform Glasses Down to Absolute Zero

Science.gov (United States)

Zhang, G.; Stillinger, F. H.; Torquato, S.

2016-11-01

Rapid cooling of liquids below a certain temperature range can result in a transition to glassy states. The traditional understanding of glasses includes their thermodynamic metastability with respect to crystals. However, here we present specific examples of interactions that eliminate the possibilities of crystalline and quasicrystalline phases, while creating mechanically stable amorphous glasses down to absolute zero temperature. We show that this can be accomplished by introducing a new ideal state of matter called a “perfect glass”. A perfect glass represents a soft-interaction analog of the maximally random jammed (MRJ) packings of hard particles. These latter states can be regarded as the epitome of a glass since they are out of equilibrium, maximally disordered, hyperuniform, mechanically rigid with infinite bulk and shear moduli, and can never crystallize due to configuration-space trapping. Our model perfect glass utilizes two-, three-, and four-body soft interactions while simultaneously retaining the salient attributes of the MRJ state. These models constitute a theoretical proof of concept for perfect glasses and broaden our fundamental understanding of glass physics. A novel feature of equilibrium systems of identical particles interacting with the perfect-glass potential at positive temperature is that they have a non-relativistic speed of sound that is infinite.

Chemical composition analysis and product consistency tests to support enhanced Hanford waste glass models: Results for the January, March, and April 2015 LAW glasses

Energy Technology Data Exchange (ETDEWEB)

Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Riley, W. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Best, D. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2015-09-03

In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for several simulated low activity waste (LAW) glasses (designated as the January, March, and April 2015 LAW glasses) fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation regions of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions.

Dantrolene is neuroprotective in Huntington's disease transgenic mouse model

Directory of Open Access Journals (Sweden)

Chen Xi

2011-11-01

Full Text Available Abstract Background Huntington's disease (HD is a progressive neurodegenerative disorder caused by a polyglutamine expansion in the Huntingtin protein which results in the selective degeneration of striatal medium spiny neurons (MSNs. Our group has previously demonstrated that calcium (Ca2+ signaling is abnormal in MSNs from the yeast artificial chromosome transgenic mouse model of HD (YAC128. Moreover, we demonstrated that deranged intracellular Ca2+ signaling sensitizes YAC128 MSNs to glutamate-induced excitotoxicity when compared to wild type (WT MSNs. In previous studies we also observed abnormal neuronal Ca2+ signaling in neurons from spinocerebellar ataxia 2 (SCA2 and spinocerebellar ataxia 3 (SCA3 mouse models and demonstrated that treatment with dantrolene, a ryanodine receptor antagonist and clinically relevant Ca2+ signaling stabilizer, was neuroprotective in experiments with these mouse models. The aim of the current study was to evaluate potential beneficial effects of dantrolene in experiments with YAC128 HD mouse model. Results The application of caffeine and glutamate resulted in increased Ca2+ release from intracellular stores in YAC128 MSN cultures when compared to WT MSN cultures. Pre-treatment with dantrolene protected YAC128 MSNs from glutamate excitotoxicty, with an effective concentration of 100 nM and above. Feeding dantrolene (5 mg/kg twice a week to YAC128 mice between 2 months and 11.5 months of age resulted in significantly improved performance in the beam-walking and gait-walking assays. Neuropathological analysis revealed that long-term dantrolene feeding to YAC128 mice significantly reduced the loss of NeuN-positive striatal neurons and reduced formation of Httexp nuclear aggregates. Conclusions Our results support the hypothesis that deranged Ca2+ signaling plays an important role in HD pathology. Our data also implicate the RyanRs as a potential therapeutic target for the treatment of HD and demonstrate that Ryan

Dantrolene is neuroprotective in Huntington's disease transgenic mouse model.

Science.gov (United States)

Chen, Xi; Wu, Jun; Lvovskaya, Svetlana; Herndon, Emily; Supnet, Charlene; Bezprozvanny, Ilya

2011-11-25

Huntington's disease (HD) is a progressive neurodegenerative disorder caused by a polyglutamine expansion in the Huntingtin protein which results in the selective degeneration of striatal medium spiny neurons (MSNs). Our group has previously demonstrated that calcium (Ca2+) signaling is abnormal in MSNs from the yeast artificial chromosome transgenic mouse model of HD (YAC128). Moreover, we demonstrated that deranged intracellular Ca2+ signaling sensitizes YAC128 MSNs to glutamate-induced excitotoxicity when compared to wild type (WT) MSNs. In previous studies we also observed abnormal neuronal Ca2+ signaling in neurons from spinocerebellar ataxia 2 (SCA2) and spinocerebellar ataxia 3 (SCA3) mouse models and demonstrated that treatment with dantrolene, a ryanodine receptor antagonist and clinically relevant Ca2+ signaling stabilizer, was neuroprotective in experiments with these mouse models. The aim of the current study was to evaluate potential beneficial effects of dantrolene in experiments with YAC128 HD mouse model. The application of caffeine and glutamate resulted in increased Ca2+ release from intracellular stores in YAC128 MSN cultures when compared to WT MSN cultures. Pre-treatment with dantrolene protected YAC128 MSNs from glutamate excitotoxicty, with an effective concentration of 100 nM and above. Feeding dantrolene (5 mg/kg) twice a week to YAC128 mice between 2 months and 11.5 months of age resulted in significantly improved performance in the beam-walking and gait-walking assays. Neuropathological analysis revealed that long-term dantrolene feeding to YAC128 mice significantly reduced the loss of NeuN-positive striatal neurons and reduced formation of Httexp nuclear aggregates. Our results support the hypothesis that deranged Ca2+ signaling plays an important role in HD pathology. Our data also implicate the RyanRs as a potential therapeutic target for the treatment of HD and demonstrate that RyanR inhibitors and Ca2+ signaling stabilizers such as

Simple solvable energy-landscape model that shows a thermodynamic phase transition and a glass transition.

Science.gov (United States)

Naumis, Gerardo G

2012-06-01

When a liquid melt is cooled, a glass or phase transition can be obtained depending on the cooling rate. Yet, this behavior has not been clearly captured in energy-landscape models. Here, a model is provided in which two key ingredients are considered in the landscape, metastable states and their multiplicity. Metastable states are considered as in two level system models. However, their multiplicity and topology allows a phase transition in the thermodynamic limit for slow cooling, while a transition to the glass is obtained for fast cooling. By solving the corresponding master equation, the minimal speed of cooling required to produce the glass is obtained as a function of the distribution of metastable states.

Modeling the dissolution behavior of defense waste glass in a salt repository environment

International Nuclear Information System (INIS)

McGrain, B.P.

1988-02-01

A mechanistic model describing a dynamic mass balance between the production and consumption of dissolved silica was found to describe the dissolution behavior of SRL-165 defense waste glass in a high-magnesium brine (PBB3) at a temperature of 90 0 C. The synergistic effect of the waste package container on the glass dissolution rate was found to depend on a precipitation reaction for a ferrous silicate mineral. The model predicted that the ferrous silicate precipitate should be variable in composition where the iron/silica stoichiometry depended on the metal/glass surface area ratio used in the experiment. This prediction was confirmed experimentally by the variable iron/silica ratios observed in filtered leachates. However, the interaction between dissolved silica and iron corrosion products needs to be much better understood before the model can be used with confidence in predicting radionuclide release rates for a salt repository. 25 refs., 4 figs., 1 tab

Establishment of mouse neuron and microglial cell co-cultured models and its action mechanism.

Science.gov (United States)

Zhang, Bo; Yang, Yunfeng; Tang, Jun; Tao, Yihao; Jiang, Bing; Chen, Zhi; Feng, Hua; Yang, Liming; Zhu, Gang

2017-06-27

The objective of this study is to establish a co-culture model of mouse neurons and microglial cells, and to analyze the mechanism of action of oxygen glucose deprivation (OGD) and transient oxygen glucose deprivation (tOGD) preconditioning cell models. Mouse primary neurons and BV2 microglial cells were successfully cultured, and the OGD and tOGD models were also established. In the co-culture of mouse primary neurons and microglial cells, the cell number of tOGD mouse neurons and microglial cells was larger than the OGD cell number, observed by a microscope. CCK-8 assay result showed that at 1h after treatment, the OD value in the control group is lower compared to all the other three groups (P control group compared to other three groups (P neurons cells were cultured. In the meantime mouse BV2 microglia cells were cultured. Two types of cells were co-cultured, and OGD and tOGD cell models were established. There were four groups in the experiment: control group (OGD), treatment group (tOGD+OGD), placebo group (tOGD+OGD+saline) and minocycline intervention group (tOGD+OGD+minocycline). CCK-8 kit was used to detect cell viability and flow cytometry was used to detect apoptosis. In this study, mouse primary neurons and microglial cells were co-cultured. The OGD and tOGD models were established successfully. tOGD was able to effectively protect neurons and microglial cells from damage, and inhibit the apoptosis caused by oxygen glucose deprivation.

Composition models for the viscosity and chemical durability of West Valley related nuclear waste glasses

International Nuclear Information System (INIS)

Feng, X.; Saad, E.E.; Freeborn, W.P.; Macedo, P.B.; Pegg, I.L.; Sassoon, R.E.; Barkatt, A.; Finger, S.M.

1988-01-01

There are two important criteria that must be satisfied by a nuclear waste glass durability and processability. The chemical composition of the glass must be such that it does not dissolve or erode appreciably faster than the decay of the radioactive materials embedded in it. The second criterion, processability, means that the glass must melt with ease, must be easily pourable, and must not crystallize appreciably. This paper summarizes the development of simple models for predicting the durability and viscosity of nuclear waste glasses from their composition

Analytical Plan for Roman Glasses

Energy Technology Data Exchange (ETDEWEB)

Strachan, Denis M.; Buck, Edgar C.; Mueller, Karl T.; Schwantes, Jon M.; Olszta, Matthew J.; Thevuthasan, Suntharampillai; Heeren, Ronald M.

2011-01-01

Roman glasses that have been in the sea or underground for about 1800 years can serve as the independent “experiment” that is needed for validation of codes and models that are used in performance assessment. Two sets of Roman-era glasses have been obtained for this purpose. One set comes from the sunken vessel the Iulia Felix; the second from recently excavated glasses from a Roman villa in Aquileia, Italy. The specimens contain glass artifacts and attached sediment or soil. In the case of the Iulia Felix glasses quite a lot of analytical work has been completed at the University of Padova, but from an archaeological perspective. The glasses from Aquileia have not been so carefully analyzed, but they are similar to other Roman glasses. Both glass and sediment or soil need to be analyzed and are the subject of this analytical plan. The glasses need to be analyzed with the goal of validating the model used to describe glass dissolution. The sediment and soil need to be analyzed to determine the profile of elements released from the glass. This latter need represents a significant analytical challenge because of the trace quantities that need to be analyzed. Both pieces of information will yield important information useful in the validation of the glass dissolution model and the chemical transport code(s) used to determine the migration of elements once released from the glass. In this plan, we outline the analytical techniques that should be useful in obtaining the needed information and suggest a useful starting point for this analytical effort.

Modeling of evaporation processes in glass melting furnaces

NARCIS (Netherlands)

Limpt, van J.A.C.

2007-01-01

The majority of glass furnaces worldwide, apply fossil fuel combustion to transfer heat directly by radiation from the combustion processes to the melting batch and glass melt. During these high temperature melting processes, some glass components, such as: sodium, potassium, boron and lead species

Break-glass handling exceptional situations in access control

CERN Document Server

Petritsch, Helmut

2014-01-01

Helmut Petritsch describes the first holistic approach to Break-Glass which covers the whole life-cycle: from access control modeling (pre-access), to logging the security-relevant system state during Break-Glass accesses (at-access), and the automated analysis of Break-Glass accesses (post-access). Break-Glass allows users to override security restrictions in exceptional situations. While several Break-Glass models specific to given access control models have already been discussed in research (e.g., extending RBAC with Break-Glass), the author introduces a generic Break-Glass model. The pres

Glass Composition Constraint Recommendations for Use in Life-Cycle Mission Modeling

Energy Technology Data Exchange (ETDEWEB)

McCloy, John S.; Vienna, John D.

2010-05-03

The component concentration limits that most influence the predicted Hanford life-cycle HLW glass volume by HTWOS were re-evaluated. It was assumed that additional research and development work in glass formulation and melter testing would be performed to improve the understanding of component effects on the processability and product quality of these HLW glasses. Recommendations were made to better estimate the potential component concentration limits that could be applied today while technology development is underway to best estimate the volume of HLW glass that will eventually be produced at Hanford. The limits for concentrations of P2O5, Bi2O3, and SO3 were evaluated along with the constraint used to avoid nepheline formation in glass. Recommended concentration limits were made based on the current HLW glass property models being used by HTWOS (Vienna et al. 2009). These revised limits are: 1) The current ND should be augmented by the OB limit of OB ≤ 0.575 so that either the normalized silica (NSi) is less that the 62% limit or the OB is below the 0.575 limit. 2) The mass fraction of P2O5 limit should be revised to allow for up to 4.5 wt%, depending on CaO concentrations. 3) A Bi2O3 concentration limit of 7 wt% should be used. 4) The salt accumulation limit of 0.5 wt% SO3 may be increased to 0.6 wt%. Again, these revised limits do not obviate the need for further testing, but make it possible to more accurately predict the impact of that testing on ultimate HLW glass volumes.

Predictive Surface Roughness Model for End Milling of Machinable Glass Ceramic

Energy Technology Data Exchange (ETDEWEB)

Reddy, M Mohan; Gorin, Alexander [School of Engineering and Science, Curtin University of Technology, Sarawak (Malaysia); Abou-El-Hossein, K A, E-mail: mohan.m@curtin.edu.my [Mechanical and Aeronautical Department, Nelson Mandela Metropolitan University, Port Elegebeth, 6031 (South Africa)

2011-02-15

Advanced ceramics of Machinable glass ceramic is attractive material to produce high accuracy miniaturized components for many applications in various industries such as aerospace, electronics, biomedical, automotive and environmental communications due to their wear resistance, high hardness, high compressive strength, good corrosion resistance and excellent high temperature properties. Many research works have been conducted in the last few years to investigate the performance of different machining operations when processing various advanced ceramics. Micro end-milling is one of the machining methods to meet the demand of micro parts. Selecting proper machining parameters are important to obtain good surface finish during machining of Machinable glass ceramic. Therefore, this paper describes the development of predictive model for the surface roughness of Machinable glass ceramic in terms of speed, feed rate by using micro end-milling operation.

Predictive Surface Roughness Model for End Milling of Machinable Glass Ceramic

International Nuclear Information System (INIS)

Reddy, M Mohan; Gorin, Alexander; Abou-El-Hossein, K A

2011-01-01

Advanced ceramics of Machinable glass ceramic is attractive material to produce high accuracy miniaturized components for many applications in various industries such as aerospace, electronics, biomedical, automotive and environmental communications due to their wear resistance, high hardness, high compressive strength, good corrosion resistance and excellent high temperature properties. Many research works have been conducted in the last few years to investigate the performance of different machining operations when processing various advanced ceramics. Micro end-milling is one of the machining methods to meet the demand of micro parts. Selecting proper machining parameters are important to obtain good surface finish during machining of Machinable glass ceramic. Therefore, this paper describes the development of predictive model for the surface roughness of Machinable glass ceramic in terms of speed, feed rate by using micro end-milling operation.

Shear viscosity of glass-forming melts in the liquid-glass transition region

International Nuclear Information System (INIS)

Sanditov, D. S.

2010-01-01

A new approach to interpreting the hole-activation model of a viscous flow of glass-forming liquids is proposed. This model underlies the development of the concept on the exponential temperature dependence of the free energy of activation of a flow within the range of the liquid-glass transition in complete agreement with available experimental data. The 'formation of a fluctuation hole' in high-heat glass-forming melts is considered as a small-scale low-activation local deformation of a structural network, i.e., the quasi-lattice necessary for the switching of the valence bond, which is the main elementary event of viscous flow of glasses and their melts. In this sense, the hole formation is a conditioned process. A drastic increase in the activation free energy of viscous flow in the liquid-glass transition region is explained by a structural transformation that is reduced to a limiting local elastic deformation of the structural network, which, in turn, originates from the excitation (critical displacement) of a bridging atom like the oxygen atom in the Si-O-Si bridge. At elevated temperatures, as a rule, a necessary amount of excited bridging atoms (locally deformed regions of the structural network) always exists, and the activation free energy of viscous flow is almost independent of temperature. The hole-activation model is closely connected with a number of well-known models describing the viscous flow of glass-forming liquids (the Avramov-Milchev, Nemilov, Ojovan, and other models).

Conditional Expression of Human 15-Lipoxygenase-1 in Mouse Prostate Induces Prostatic Intraepithelial Neoplasia: The FLiMP Mouse Model

Directory of Open Access Journals (Sweden)

Uddhav P. Kelavkar

2006-06-01

Full Text Available The incidence and mortality of prostate cancer (PCa vary greatly in different geographic regions, for which lifestyle factors, such as dietary fat intake, have been implicated. Human 15-lipoxygenase-1 (h15-LO-1, which metabolizes polyunsaturated fatty acids, is a highly regulated, tissue-specific, lipid-peroxidating enzyme that functions in physiological membrane remodeling and in the pathogenesis of atherosclerosis, inflammation, and carcinogenesis. We have shown that aberrant overexpression of 15-LO-1 occurs in human PCa, particularly high-grade PCa, and in high-grade prostatic intraepithelial neoplasia (HGPIN, and that the murine orthologue is increased in SV40-based genetically engineered mouse (GEM models of PCa, such as LADY and TRansgenic Adenocarcinoma of Mouse Prostate. To further define the role of 15-LO-1 in prostate carcinogenesis, we established a novel GEM model with targeted overexpression of h15-LO-1 in the prostate [human fifteen lipoxygenase-1 in mouse prostate (FLiMP]. We used a Cre- mediated and a loxP-mediated recombination strategy to target h15-LO-1 specifically to the prostate of C57BL/6 mice. Wild-type (wt, FLiMP+/-, and FLiMP+/+ mice aged 7 to 21, 24 to 28, and 35 weeks were characterized by histopathology, immunohistochemistry (IHC, and DNA/RNA and enzyme analyses. Compared to wt mice, h15-LO-1 enzyme activity was increased similarly in both homozygous FLiMP+/+ and hemizygous FLiMP+/- prostates. Dorsolateral and ventral prostates of FLiMP mice showed focal and progressive epithelial hyperplasia with nuclear atypia, indicative of the definition of mouse prostatic intraepithelial neoplasia (mPIN according to the National Cancer Institute. These foci showed increased proliferation by Ki-67 IHC. No progression to invasive PCa was noted up to 35 weeks. By IHC, h15-LO-1 expression was limited to luminal epithelial cells, with increased expression in mPIN foci (similar to human HGPIN. In summary, targeted overexpression of h

Spectral Unmixing Modeling of the Aristarchus Pyroclastic Deposit: Assessing the Eruptive History of Glass-Rich Regional Lunar Pyroclastic Deposits

Science.gov (United States)

Jawin, E. R.; Head, J. W., III; Cannon, K.

2017-12-01

The Aristarchus pyroclastic deposit in central Oceanus Procellarum is understood to have formed in a gas-rich explosive volcanic eruption, and has been observed to contain abundant volcanic glass. However, the interpreted color (and therefore composition) of the glass has been debated. In addition, previous analyses of the pyroclastic deposit have been performed using lower resolution data than are currently available. In this work, a nonlinear spectral unmixing model was applied to Moon Mineralogy Mapper (M3) data of the Aristarchus plateau to investigate the detailed mineralogic and crystalline nature of the Aristarchus pyroclastic deposit by using spectra of laboratory endmembers including a suite of volcanic glasses returned from the Apollo 15 and 17 missions (green, orange, black beads), as well as synthetic lunar glasses (orange, green, red, yellow). Preliminary results of the M3 unmixing model suggest that spectra of the pyroclastic deposit can be modeled by a mixture composed predominantly of a featureless endmember approximating space weathering and a smaller component of glass. The modeled spectra were most accurate with a synthetic orange glass endmember, relative to the other glasses analyzed in this work. The results confirm that there is a detectable component of glass in the Aristarchus pyroclastic deposit which may be similar to the high-Ti orange glass seen in other regional pyroclastic deposits, with only minimal contributions of other crystalline minerals. The presence of volcanic glass in the pyroclastic deposit, with the low abundance of crystalline material, would support the model that the Aristarchus pyroclastic deposit formed in a long-duration, hawaiian-style fire fountain eruption. No significant detection of devitrified black beads in the spectral modeling results (as was observed at the Apollo 17 landing site in the Taurus-Littrow pyroclastic deposit), suggests the optical density of the eruptive plume remained low throughout the

Mouse Models for Drug Discovery. Can New Tools and Technology Improve Translational Power?

Science.gov (United States)

Zuberi, Aamir; Lutz, Cathleen

2016-01-01

Abstract The use of mouse models in biomedical research and preclinical drug evaluation is on the rise. The advent of new molecular genome-altering technologies such as CRISPR/Cas9 allows for genetic mutations to be introduced into the germ line of a mouse faster and less expensively than previous methods. In addition, the rapid progress in the development and use of somatic transgenesis using viral vectors, as well as manipulations of gene expression with siRNAs and antisense oligonucleotides, allow for even greater exploration into genomics and systems biology. These technological advances come at a time when cost reductions in genome sequencing have led to the identification of pathogenic mutations in patient populations, providing unprecedented opportunities in the use of mice to model human disease. The ease of genetic engineering in mice also offers a potential paradigm shift in resource sharing and the speed by which models are made available in the public domain. Predictively, the knowledge alone that a model can be quickly remade will provide relief to resources encumbered by licensing and Material Transfer Agreements. For decades, mouse strains have provided an exquisite experimental tool to study the pathophysiology of the disease and assess therapeutic options in a genetically defined system. However, a major limitation of the mouse has been the limited genetic diversity associated with common laboratory mice. This has been overcome with the recent development of the Collaborative Cross and Diversity Outbred mice. These strains provide new tools capable of replicating genetic diversity to that approaching the diversity found in human populations. The Collaborative Cross and Diversity Outbred strains thus provide a means to observe and characterize toxicity or efficacy of new therapeutic drugs for a given population. The combination of traditional and contemporary mouse genome editing tools, along with the addition of genetic diversity in new modeling

Mouse Models for Drug Discovery. Can New Tools and Technology Improve Translational Power?

Science.gov (United States)

Zuberi, Aamir; Lutz, Cathleen

2016-12-01

The use of mouse models in biomedical research and preclinical drug evaluation is on the rise. The advent of new molecular genome-altering technologies such as CRISPR/Cas9 allows for genetic mutations to be introduced into the germ line of a mouse faster and less expensively than previous methods. In addition, the rapid progress in the development and use of somatic transgenesis using viral vectors, as well as manipulations of gene expression with siRNAs and antisense oligonucleotides, allow for even greater exploration into genomics and systems biology. These technological advances come at a time when cost reductions in genome sequencing have led to the identification of pathogenic mutations in patient populations, providing unprecedented opportunities in the use of mice to model human disease. The ease of genetic engineering in mice also offers a potential paradigm shift in resource sharing and the speed by which models are made available in the public domain. Predictively, the knowledge alone that a model can be quickly remade will provide relief to resources encumbered by licensing and Material Transfer Agreements. For decades, mouse strains have provided an exquisite experimental tool to study the pathophysiology of the disease and assess therapeutic options in a genetically defined system. However, a major limitation of the mouse has been the limited genetic diversity associated with common laboratory mice. This has been overcome with the recent development of the Collaborative Cross and Diversity Outbred mice. These strains provide new tools capable of replicating genetic diversity to that approaching the diversity found in human populations. The Collaborative Cross and Diversity Outbred strains thus provide a means to observe and characterize toxicity or efficacy of new therapeutic drugs for a given population. The combination of traditional and contemporary mouse genome editing tools, along with the addition of genetic diversity in new modeling systems

Pressure dependence of glass transition in As2Te3 glass.

Science.gov (United States)

Ramesh, K

2014-07-24

Amorphous solids prepared from their melt state exhibit glass transition phenomenon upon heating. Viscosity, specific heat, and thermal expansion coefficient of the amorphous solids show rapid changes at the glass transition temperature (Tg). Generally, application of high pressure increases the Tg and this increase (a positive dT(g)/dP) has been understood adequately with free volume and entropy models which are purely thermodynamic in origin. In this study, the electrical resistivity of semiconducting As(2)Te(3) glass at high pressures as a function of temperature has been measured in a Bridgman anvil apparatus. Electrical resistivity showed a pronounced change at Tg. The Tg estimated from the slope change in the resistivity-temperature plot shows a decreasing trend (negative dT(g)/dP). The dT(g)/dP was found to be -2.36 °C/kbar for a linear fit and -2.99 °C/kbar for a polynomial fit in the pressure range 1 bar to 9 kbar. Chalcogenide glasses like Se, As(2)Se(3), and As(30)Se(30)Te(40) show a positive dT(g)/dP which is very well understood in terms of the thermodynamic models. The negative dT(g)/dP (which is generally uncommon in liquids) observed for As(2)Te(3) glass is against the predictions of the thermodynamic models. The Adam-Gibbs model of viscosity suggests a direct relationship between the isothermal pressure derivative of viscosity and the relaxational expansion coefficient. When the sign of the thermal expansion coefficient is negative, dT(g)/dP = Δk/Δα will be less than zero, which can result in a negative dT(g)/dP. In general, chalcogenides rich in tellurium show a negative thermal expansion coefficient (NTE) in the supercooled and stable liquid states. Hence, the negative dT(g)/dP observed in this study can be understood on the basis of the Adams-Gibbs model. An electronic model proposed by deNeufville and Rockstad finds a linear relation between Tg and the optical band gap (Eg) for covalent semiconducting glasses when they are grouped

Effect of the initial stage of annealing on modeling of enthalpy relaxation in a hyperquenched glass

DEFF Research Database (Denmark)

Zhang, Yanfei; Guo, Xiaoju; Yue, Yuanzheng

2013-01-01

One of the major challenges in glass relaxation study is to establish a universal model describing the enthalpy relaxation in both the hyperquenched glass (HQG) (i.e., far from equilibrium) and the partially annealed hyperquenched glass(AHQG). In particular, the detailed features of the enthalpy ...... proposed composite relaxation function [L. Hornboell, et al., Chem. Phys. Lett. 1-3 (2010) 37] is a reasonable approach for describing those features. In addition, our modeling results imply that the structural heterogeneity plays a crucial role in relaxation of HQG....

A preclinical mouse model of invasive lobular breast cancer metastasis

NARCIS (Netherlands)

Doornebal, Chris W.; Klarenbeek, Sjoerd; Braumuller, Tanya M.; Klijn, Christiaan N.; Ciampricotti, Metamia; Hau, Cheei-Sing; Hollmann, Markus W.; Jonkers, Jos; de Visser, Karin E.

2013-01-01

Metastatic disease accounts for more than 90% of cancer-related deaths, but the development of effective antimetastatic agents has been hampered by the paucity of clinically relevant preclinical models of human metastatic disease. Here, we report the development of a mouse model of spontaneous

Design of a day tank glass furnace using a transient model and steady-state computation fluid dynamics

International Nuclear Information System (INIS)

Díaz-Ibarra, Oscar; Abad, Pablo; Molina, Alejandro

2013-01-01

To design day tanks with energy efficiency and good operation standards, a detailed transient model that considers the melting, refining, cooling and working stages of the glass production process was developed. With the model, the required power input was determined, with glass coverage with batch (β) as parameter, for a furnace with a daily production of 1130 kg of soda-lime glass and 14 h for melting/refining. A detailed analysis of the energy balance with the model showed that during the daily cycle about 70% of the energy input is released with the flue gas. During the working stage most of the energy escapes through the doors. As the peak of energy consumption is during the refining process, the power requirement for this stage defines the global power requirement. Calculated energy efficiencies vary between 13% and 16% for β = 70% and 30% respectively. A steady state CFD simulation of the combustion chamber and glass tank shows that a side-fired burner configuration allows for lower gas velocities and temperatures close to the glass and the furnace walls while guaranteeing the same heat transfer characteristics to the glass than the more traditional end-fired (U-type) furnaces. -- Highlights: ► A transient model of a day tank glass furnace captures main process characteristics. ► Heat loss through doors during working stage impacts thermal efficiency. ► A side-fired burner configuration should be preferred to an end-fired approach

Modelling of the draining of a molten glass heated by induction

International Nuclear Information System (INIS)

Lima-Da-Silva, Marcio

2014-01-01

This thesis is part of the development of a new technology of oxides melting in a furnace heated by induction. The technology studied involves strong interactions between electromagnetic, thermal and hydrodynamic phenomena in a flow with physical properties strongly dependents of the temperature. The aim of the thesis is the modelling of the process by coupling closely the Joule heating, the mechanical stirring and the draining of the furnace. The modeling of the time evolution of the interface between glass and air during the emptying of the cold crucible was performed. Regarding the methodology, we chose to combine two scientific codes: Flux for the electromagnetic calculation and Fluent for thermal-hydraulics. The evolution of the free surface was treated by the multiphasic method 'Volume-Of-Fluid - VOF' and the mechanical stirring by the 'Moving Reference Frame' and the 'Sliding Mesh'. First of all, we considered the draining of a tank filled with a silicon oil of high-viscosity without mechanical stirring. This initial model took into account studies of hydraulic similarity between the silicon oil and the glass. Then we superimposed the forced flow creates by the mechanical stirrer, the thermal and the electromagnetic phenomena in order to model the flow of the molten glass. The final model can provide various parameters, including the time needed to drain the furnace, the heat transfer flux and the time evolution of the mass flow rate and of the temperature inside de furnace. (author) [fr

Biology and therapy of inherited retinal degenerative disease: insights from mouse models

Science.gov (United States)

Veleri, Shobi; Lazar, Csilla H.; Chang, Bo; Sieving, Paul A.; Banin, Eyal; Swaroop, Anand

2015-01-01

Retinal neurodegeneration associated with the dysfunction or death of photoreceptors is a major cause of incurable vision loss. Tremendous progress has been made over the last two decades in discovering genes and genetic defects that lead to retinal diseases. The primary focus has now shifted to uncovering disease mechanisms and designing treatment strategies, especially inspired by the successful application of gene therapy in some forms of congenital blindness in humans. Both spontaneous and laboratory-generated mouse mutants have been valuable for providing fundamental insights into normal retinal development and for deciphering disease pathology. Here, we provide a review of mouse models of human retinal degeneration, with a primary focus on diseases affecting photoreceptor function. We also describe models associated with retinal pigment epithelium dysfunction or synaptic abnormalities. Furthermore, we highlight the crucial role of mouse models in elucidating retinal and photoreceptor biology in health and disease, and in the assessment of novel therapeutic modalities, including gene- and stem-cell-based therapies, for retinal degenerative diseases. PMID:25650393

On-site Raman analysis of ancient glasses and stained-glass windows: modeling, procedure, lixiviation and characterization

International Nuclear Information System (INIS)

Tournie, Aurelie

2009-01-01

The aim of this study is to estimate the possibilities of Raman spectrometry to identify on site old glasses (objects, stained-glass windows...) whatever been their preserving state. The efficiency of Raman analysis depends strongly of the structural organization of glasses and then of their technological history. In order to differentiate the great silicate family compounds from their Raman analysis, a methodology has been developed: data acquisition and spectrum processing, Raman parameters extraction and classification of these glasses. This approach has then been extended to crystalline phosphates and silicates. Beforehand, correlations between crystallo-chemical parameters and vibrational signatures have been considered. The old glasses are often recovered by a corrosion layer which induces important changes on the Raman signature. Four layers have been identified and characterized by a multi-scale study: leached porous layer, transition zone, cracked zone and sound glass. The results show that only an analytical chemistry approach (databases of Raman signatures) is not sufficient and that a solid chemistry and physics approach is required to explain the spectral answers and extract the relevant parameters from glasses preserving [fr

Transcranial magnetic stimulation of mouse brain using high-resolution anatomical models

Science.gov (United States)

Crowther, L. J.; Hadimani, R. L.; Kanthasamy, A. G.; Jiles, D. C.

2014-05-01

Transcranial magnetic stimulation (TMS) offers the possibility of non-invasive treatment of brain disorders in humans. Studies on animals can allow rapid progress of the research including exploring a variety of different treatment conditions. Numerical calculations using animal models are needed to help design suitable TMS coils for use in animal experiments, in particular, to estimate the electric field induced in animal brains. In this paper, we have implemented a high-resolution anatomical MRI-derived mouse model consisting of 50 tissue types to accurately calculate induced electric field in the mouse brain. Magnetic field measurements have been performed on the surface of the coil and compared with the calculations in order to validate the calculated magnetic and induced electric fields in the brain. Results show how the induced electric field is distributed in a mouse brain and allow investigation of how this could be improved for TMS studies using mice. The findings have important implications in further preclinical development of TMS for treatment of human diseases.

Hypothalamic food intake regulation in a cancer-cachectic mouse model

NARCIS (Netherlands)

Dwarkasing, J.T.; Dijk, van M.; Dijk, F.J.; Boekschoten, M.V.; Faber, J.; Argiles, J.M.; Laviano, A.; Müller, M.R.; Witkamp, R.F.; Norren, van K.

2014-01-01

Background Appetite is frequently affected in cancer patients leading to anorexia and consequently insufficient food intake. In this study, we report on hypothalamic gene expression profile of a cancer-cachectic mouse model with increased food intake. In this model, mice bearing C26 tumour have an

AFM assessment of the surface nano/microstructure on chemically damaged historical and model glasses

International Nuclear Information System (INIS)

Carmona, Noemi; Kowal, Andrzej; Rincon, Jesus-Maria; Villegas, Maria-Angeles

2010-01-01

Surface chemical damage on selected historical glasses from 13th to 19th centuries was evaluated by means of atomic force microscopy (AFM). Nano- and microstructure, roughness and topography of ancient glass samples have been compared with those of model glasses prepared by conventional melting at the laboratory with similar compositions to those most frequently found in historical glass pieces. The results obtained allow discussing the chemical degradation mechanisms in terms of the acid and/or basic chemical attack carried out by the combination of gaseous pollutants and environmental humidity. Even though deep corrosion features escape to the observation order of magnitude of the AF microscope used, the AFM technique proves to be quite useful for the study and evaluation of the most common surface pathologies of historical glasses with different compositions once submitted to natural weathering.

AFM assessment of the surface nano/microstructure on chemically damaged historical and model glasses

Energy Technology Data Exchange (ETDEWEB)

Carmona, Noemi [Centro Nacional de Investigaciones Metalurgicas, CSIC, Avda. Gregorio del Amo, 8, 28040 Madrid (Spain); Kowal, Andrzej [Institute of Catalysis and Surface Chemistry, PAN, ul. Niezapominajek 8, 30239 Cracow (Poland); Rincon, Jesus-Maria [Instituto Eduardo Torroja de Ciencias de la Construccion, CSIC, C. Serrano Galvache s/n, 28033 Madrid (Spain); Villegas, Maria-Angeles, E-mail: mariangeles.villegas@cchs.csic.es [Centro Nacional de Investigaciones Metalurgicas, CSIC, Avda. Gregorio del Amo, 8, 28040 Madrid (Spain); Instituto de Historia, Centro de Ciencias Humanas y Sociales, CSIC, C. Albasanz, 26-28, 28037 Madrid (Spain)

2010-01-15

Surface chemical damage on selected historical glasses from 13th to 19th centuries was evaluated by means of atomic force microscopy (AFM). Nano- and microstructure, roughness and topography of ancient glass samples have been compared with those of model glasses prepared by conventional melting at the laboratory with similar compositions to those most frequently found in historical glass pieces. The results obtained allow discussing the chemical degradation mechanisms in terms of the acid and/or basic chemical attack carried out by the combination of gaseous pollutants and environmental humidity. Even though deep corrosion features escape to the observation order of magnitude of the AF microscope used, the AFM technique proves to be quite useful for the study and evaluation of the most common surface pathologies of historical glasses with different compositions once submitted to natural weathering.

New Erbium Doped Antimony Glasses for Laser and Glass ...

African Journals Online (AJOL)

Because of the special spectroscopic properties of the rare earth ions, rare earth doped glasses are widely used in bulk and fiber lasers or amplifiers. The modelling of lasers and searching for new laser transitions require a precise knowledge of the spectroscopic properties of rare earth ions in different host glasses.

Impaired spatial processing in a mouse model of fragile X syndrome.

Science.gov (United States)

Ghilan, Mohamed; Bettio, Luis E B; Noonan, Athena; Brocardo, Patricia S; Gil-Mohapel, Joana; Christie, Brian R

2018-05-17

Fragile X syndrome (FXS) is the most common form of inherited intellectual impairment. The Fmr1 -/y mouse model has been previously shown to have deficits in context discrimination tasks but not in the elevated plus-maze. To further characterize this FXS mouse model and determine whether hippocampal-mediated behaviours are affected in these mice, dentate gyrus (DG)-dependent spatial processing and Cornu ammonis 1 (CA1)-dependent temporal order discrimination tasks were evaluated. In agreement with previous findings of long-term potentiation deficits in the DG of this transgenic model of FXS, the results reported here demonstrate that Fmr1 -/y mice perform poorly in the DG-dependent metric change spatial processing task. However, Fmr1 -/y mice did not present deficits in the CA1-dependent temporal order discrimination task, and were able to remember the order in which objects were presented to them to the same extent as their wild-type littermate controls. These data suggest that the previously reported subregional-specific differences in hippocampal synaptic plasticity observed in the Fmr1 -/y mouse model may manifest as selective behavioural deficits in hippocampal-dependent tasks. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Modelling the dissolution of borosilicate glasses for radioactive waste disposal with the PHREEQE/GLASSOL code: theory and practice

International Nuclear Information System (INIS)

Curti, E.

1991-02-01

A model describing the corrosion kinetics of silicate glasses has been developed by Grambow in recent years. In this report, the theoretical background of the model is thoroughly discussed, and its practical use demonstrated. The main objectives were: 1) to test the validity of the basic assumptions on which the model relies, and 2) to assess whether it can be applied to the safety analysis of a Swiss final repository for high-level radioactive waste. Transition State Theory, a tool based on quantum mechanical principles, has been used by Grambow to derive a general kinetic equation for the corrosion of silicate glasses. This equation predicts successfully the observed dependence of the corrosion rate on the silicic acid concentration in solution according to a first order kinetics law. However, some parameters required by this equation are determined on the base of questionable assumptions. In particular, the simplistic surface complexation model used for the calculation of the free energy of the glass-water reaction yields, for the protonation of silicon on the glass surface, results which are not consistent with the experimental findings. Further, although the model predicts a unique value, common to all silicate glasses, for the activation energy of the rate-determining elementary reaction, leaching experiments conducted on a wide variety of glasses suggest that this quantity may vary by a factor 2. In its present form, the model is judged to be unsuitable for the safety analysis of the Swiss final repository. The reasons include: 1) the model neglects the potential effects of diffusive transport and silica sorption in a bentonite backfill on the glass corrosion kinetics, 2) the release of radionuclides can be only modelled assuming congruent dissolution, and 3) the magnitude of the final rates of corrosion, the parameter defining the maximal lifetime of the glass matrix, is still not known with sufficient precision. (author) figs., tabs., 27 refs

Neuropathological assessment and validation of mouse models for Alzheimer's disease: applying NIA-AA guidelines

Directory of Open Access Journals (Sweden)

C. Dirk Keene

2016-06-01

Full Text Available Dozens of transgenic mouse models, generally based on mutations associated with familial Alzheimer's disease (AD, have been developed, in part, for preclinical testing of candidate AD therapies. However, none of these models has successfully predicted the clinical efficacy of drugs for treating AD patients. Therefore, development of more translationally relevant AD mouse models remains a critical unmet need in the field. A concept not previously implemented in AD preclinical drug testing is the use of mouse lines that have been validated for neuropathological features of human AD. Current thinking suggests that amyloid plaque and neurofibrillary tangle deposition is an essential component for accurate modeling of AD. Therefore, the AD translational paradigm would require pathologic Aβ and tau deposition, a disease-relevant distribution of plaques and tangles, and a pattern of disease progression of Aβ and tau isoforms similar to the neuropathological features found in the brains of AD patients. Additional parameters useful to evaluate parallels between AD and animal models would include 1 cerebrospinal fluid (CSF AD biomarker changes with reduced Aβ and increased phospho-tau/tau; 2 structural and functional neuroimaging patterns including MRI hippocampal atrophy, fluorodeoxyglucose (FDG, and amyloid/tau PET alterations in activity and/or patterns of pathologic peptide deposition and distribution; and 3 cognitive impairment with emphasis on spatial learning and memory to distinguish presymptomatic and symptomatic mice at specific ages. A validated AD mouse model for drug testing would likely show tau-related neurofibrillary degeneration following Aβ deposition and demonstrate changes in pathology, CSF analysis, and neuroimaging that mirror human AD. Development of the ideal model would revolutionize the ability to establish the translational value of AD mouse models and serve as a platform for discussions about national phenotyping guidelines

A dystrophic Duchenne mouse model for testing human antisense oligonucleotides.

Directory of Open Access Journals (Sweden)

Marcel Veltrop

Full Text Available Duchenne muscular dystrophy (DMD is a severe muscle-wasting disease generally caused by reading frame disrupting mutations in the DMD gene resulting in loss of functional dystrophin protein. The reading frame can be restored by antisense oligonucleotide (AON-mediated exon skipping, allowing production of internally deleted, but partially functional dystrophin proteins as found in the less severe Becker muscular dystrophy. Due to genetic variation between species, mouse models with mutations in the murine genes are of limited use to test and further optimize human specific AONs in vivo. To address this we have generated the del52hDMD/mdx mouse. This model carries both murine and human DMD genes. However, mouse dystrophin expression is abolished due to a stop mutation in exon 23, while the expression of human dystrophin is abolished due to a deletion of exon 52. The del52hDMD/mdx model, like mdx, shows signs of muscle dystrophy on a histological level and phenotypically mild functional impairment. Local administration of human specific vivo morpholinos induces exon skipping and dystrophin restoration in these mice. Depending on the number of mismatches, occasional skipping of the murine Dmd gene, albeit at low levels, could be observed. Unlike previous models, the del52hDMD/mdx model enables the in vivo analysis of human specific AONs targeting exon 51 or exon 53 on RNA and protein level and muscle quality and function. Therefore, it will be a valuable tool for optimizing human specific AONs and genome editing approaches for DMD.

Joints in Tempered Glass Using Glass Dowel Discs

DEFF Research Database (Denmark)

Nielsen, Jens Henrik; Poulsen, Peter Noe

One of the major reasons for using glass in structures is its transparency; however, traditional mechanical joints such as friction joints and steel dowel pinned connections are compromising the transparency. The present paper describes a novel joint which is practically maintaining the complete...... transparency of the glass. This is achieved by using a dowel disc made entirely of tempered glass. The concept of the joint is proved by pilot tests and numerical models. From the work it is seen that the load-carrying capacity of such a connection is similar to what is found for traditionally in-plane loaded...

The impact of mouse passaging of Mycobacterium tuberculosis strains prior to virulence testing in the mouse and guinea pig aerosol models.

Directory of Open Access Journals (Sweden)

Paul J Converse

2010-04-01

Full Text Available It has been hypothesized that the virulence of lab-passaged Mycobacterium tuberculosis and recombinant M. tuberculosis mutants might be reduced due to multiple in vitro passages, and that virulence might be augmented by passage of these strains through mice before quantitative virulence testing in the mouse or guinea pig aerosol models.By testing three M. tuberculosis H37Rv samples, one deletion mutant, and one recent clinical isolate for survival by the quantitative organ CFU counting method in mouse or guinea pig aerosol or intravenous infection models, we could discern no increase in bacterial fitness as a result of passaging of M. tuberculosis strains in mice prior to quantitative virulence testing in two animal models. Surface lipid expression as assessed by neutral red staining and thin-layer chromatography for PDIM analysis also failed to identify virulence correlates.These results indicate that animal passaging of M. tuberculosis strains prior to quantitative virulence testing in mouse or guinea pig models does not enhance or restore potency to strains that may have lost virulence due to in vitro passaging. It is critical to verify virulence of parental strains before genetic manipulations are undertaken and comparisons are made.

Modeling the Structural Response of Reinforced Glass Beams using an SLA Scheme

NARCIS (Netherlands)

Louter, P.C.; Graaf, van de Anne; Rots, J.G.; Bos, Freek; Louter, Pieter Christiaan; Veer, Fred

2010-01-01

This paper investigates whether a novel computational sequentially linear analysis (SLA) technique, which is especially developed for modeling brittle material response, is applicable for modeling the structural response of metal reinforced glass beams. To do so, computational SLA results are

Mouse Chromosome Engineering for Modeling Human Disease

OpenAIRE

van der Weyden, Louise; Bradley, Allan

2006-01-01

Chromosomal rearrangements occur frequently in humans and can be disease-associated or phenotypically neutral. Recent technological advances have led to the discovery of copy-number changes previously undetected by cytogenetic techniques. To understand the genetic consequences of such genomic changes, these mutations need to be modeled in experimentally tractable systems. The mouse is an excellent organism for this analysis because of its biological and genetic similarity to humans, and the e...

Free volume model: High-temperature deformation of a Zr-based bulk metallic glass

International Nuclear Information System (INIS)

Bletry, M.; Guyot, P.; Blandin, J.J.; Soubeyroux, J.L.

2006-01-01

The homogeneous deformation of a zirconium-based bulk metallic glass is investigated in the glass transition region. Compression tests at different temperatures and strain rates have been conducted. The mechanical behavior is analyzed in the framework of the free volume model, taking into account the dependence of the flow defect concentration on deformation. The activation volume is evaluated and allows one to gather the viscosity data (for the different strain rates and temperatures) on a unique master curve. It is also shown that, due to the relation between flow defect concentration and free volume, it is not possible to deduce the equilibrium flow defect concentration directly from mechanical measurements. However, if this parameter is arbitrarily chosen, mechanical measurements give access to the other parameters of the model, these parameters for the alloy under investigation being of the same order of magnitude as those for other metallic glasses

The glass model of Muelheim-Kaerlich nuclear power station

International Nuclear Information System (INIS)

Kuttruf, H.; Lemke, W.

1986-01-01

The glass model represents the nuclear steam generator system of Muelheim-Kaerlich nuclear power station on a scale of 1:25 and in simplified form, so that the thermohydraulic behaviour in both normal operational and fault conditions can be represented. A set-up time of about one hour results in a helpful aid to instruction. (orig.) [de

Systematic assessment of microneedle injection into the mouse cornea.

Science.gov (United States)

Matthaei, Mario; Meng, Huan; Bhutto, Imran; Xu, Qingguo; Boelke, Edwin; Hanes, Justin; Jun, Albert S

2012-06-20

Corneal intrastromal injection is an important mode of gene-vector application to subepithelial layers. In a mouse model, this procedure is substantially complicated by the reduced corneal dimensions. Furthermore, it may be difficult to estimate the corneal area reached by the volume of a single injection. This study aimed to investigate intrastromal injections into the mouse cornea using different microneedles and to quantify the effect of injecting varying volumes. A reproducible injection technique is described. Forty eyes of 20 129 Sv/J mice were tested. India ink was intrastromally injected using 30° beveled 33 G needles, tri-surface 25° beveled 35 G needles, or hand-pulled and 25° beveled glass needles. Each eye received a single injection of a volume of 1 or 2 μL. Corneoscleral buttons were fixed and flat mounted for computer-assisted quantification of the affected corneal area. Histological assessment was performed to investigate the intrastromal location of the injected dye. A mean corneal area of 5.0 ± 1.4 mm(2) (mean ± SD) and 7.7 ± 1.4 mm(2) was covered by intrastromal injections of 1 and 2 μL, respectively. The mean percentage of total corneal area reached ranged from 39% to 53% for 1 μL injections, and from 65% to 81% for 2 μL injections. Injections using the 33 G needles tended to provide the highest distribution area. Perforation rates were 8% for 30° beveled 33 G needles and 44% for tri-surface beveled 35 G needles. No perforation was observed with glass needle; however, intrastromal breakage of needle tips was noted in 25% of these cases. Intracorneal injection using a 30° beveled 33 G needle was safe and effective. The use of tri-surface beveled 35 G needles substantially increased the number of corneal perforations. Glass needles may break inside the corneal stroma. Injections of 1 μL and 2 μL resulted in an overall mean of 49% and 73% respectively of total corneal area involved.

Revisiting the mouse model of oxygen-induced retinopathy

Directory of Open Access Journals (Sweden)

Kim CB

2016-05-01

Full Text Available Clifford B Kim,1,2 Patricia A D’Amore,2–4 Kip M Connor1,2 1Angiogenesis Laboratory, Massachusetts Eye and Ear, 2Department of Ophthalmology, Harvard Medical School, 3Schepens Eye Research Institute, Massachusetts Eye and Ear, 4Department of Pathology, Harvard Medical School, Boston, MA, USA Abstract: Abnormal blood vessel growth in the retina is a hallmark of many retinal diseases, such as retinopathy of prematurity (ROP, proliferative diabetic retinopathy, and the wet form of age-related macular degeneration. In particular, ROP has been an important health concern for physicians since the advent of routine supplemental oxygen therapy for premature neonates more than 70 years ago. Since then, researchers have explored several animal models to better understand ROP and retinal vascular development. Of these models, the mouse model of oxygen-induced retinopathy (OIR has become the most widely used, and has played a pivotal role in our understanding of retinal angiogenesis and ocular immunology, as well as in the development of groundbreaking therapeutics such as anti-vascular endothelial growth factor injections for wet age-related macular degeneration. Numerous refinements to the model have been made since its inception in the 1950s, and technological advancements have expanded the use of the model across multiple scientific fields. In this review, we explore the historical developments that have led to the mouse OIR model utilized today, essential concepts of OIR, limitations of the model, and a representative selection of key findings from OIR, with particular emphasis on current research progress. Keywords: ROP, OIR, angiogenesis

Modeling relations between the composition and properties of French light water reactor waste containment glass

International Nuclear Information System (INIS)

Ghaleb, D.; Dussossoy, J.L.; Fillet, C.; Pacaud, F.; Jacquet-Francillon, N.

1994-01-01

Models have been developed to calculate the density, molten-state viscosity and initial corrosion rate according to the chemical composition of glass formulations used to vitrify high-level fission product solutions from reprocessed light water reactor fuel. Developed from other published work, these models have been adapted to allow for the effects of platinoid (Ru, Pd, Rh) inclusions on the molten glass rheology. (authors). 15 refs., 10 figs., 1 tab

SON68 nuclear glass dissolution kinetics: Current state of knowledge and basis of the new GRAAL model

Energy Technology Data Exchange (ETDEWEB)

Frugier, P. [CEA Marcoule, DTCD/SECM/LCLT, BP 17171, 30207 Bagnols-sur-Ceze cedex (France)], E-mail: pierre.frugier@cea.fr; Gin, S.; Minet, Y.; Chave, T. [CEA Marcoule, DTCD/SECM/LCLT, BP 17171, 30207 Bagnols-sur-Ceze cedex (France); Bonin, B. [CEA Saclay, DEN/DIR/DS, 91191 Gif-sur-Yvette cedex (France); Godon, N.; Lartigue, J.-E.; Jollivet, P. [CEA Marcoule, DTCD/SECM/LCLT, BP 17171, 30207 Bagnols-sur-Ceze cedex (France); Ayral, A. [IEM/CNRS-ENSCM Universite Montpellier 2, CC 047, Place Eugene Bataillon, 34095 Montpellier cedex 5 (France); De Windt, L. [ENSMP, CG, 35 rue St Honore, 77305 Fontainebleau cedex (France); Santarini, G. [CEA Saclay HC/CAB, 91191 Gif-sur-Yvette cedex (France)

2008-10-15

This article summarizes the present state of knowledge concerning aqueous alteration of R7T7-type nuclear containment glasses, represented mainly by the inactive reference glass designated SON68. Based on this review, we propose to describe the glass alteration kinetics up to and including the final residual rate regime by means of a new mechanistic model known as GRAAL (glassreactivitywithallowanceforthealterationlayer). Phenomenological analysis findings are reviewed for the various glass alteration regimes: interdiffusion, initial rate, rate drop, residual rate and, under very particular circumstances, resumption of alteration. These alteration regimes are associated with predominant mechanisms. Published work interpreting and modeling these mechanisms was examined in detail. There is a broad consensus on the general mechanisms of the initial rate and even the interdiffusion regime, whereas the mechanisms controlling the rate drop remain a subject of dispute not only with regard to nuclear glasses but also for the dissolution of silicate minerals. The reaction affinity responsible for the rate drop is expressed differently by different authors and depending on the underlying theories. The disagreement concerns the nature of the phase (glass or gel) or the activated complex controlling the rate drop, which in turn determines the elements that must be taken into account in the overall affinity term. Progress in recent years, especially in identifying the mechanisms responsible for the residual rate, has shed new light on these issues, allowing us to propose new theoretical foundations for modeling the different kinetic regimes of SON68 nuclear glass dissolution. The GRAAL model considers that water diffusion in the passivating reaction zone (the gel formed under saturation conditions) is a rate-limiting step in the overall glass dissolution kinetics. Moreover, this passivation zone is a soluble phase whose stability is directly dependent on the nature of the

Mouse Xenograft Model for Mesothelioma | NCI Technology Transfer Center | TTC

Science.gov (United States)

The National Cancer Institute is seeking parties interested in collaborative research to co-develop, evaluate, or commercialize a new mouse model for monoclonal antibodies and immunoconjugates that target malignant mesotheliomas. Applications of the technology include models for screening compounds as potential therapeutics for mesothelioma and for studying the pathology of mesothelioma.

HUPO BPP Workshop on Mouse Models for Neurodegeneration--Choosing the right models.

Science.gov (United States)

Hamacher, Michael; Marcus, Katrin; Stephan, Christian; van Hall, Andre; Meyer, Helmut E

2005-09-01

The HUPO Brain Proteome Project met during the 4th Dutch Endo-Neuro-Psycho Meeting in Doorwerth, The Netherlands, on June 1, 2005, in order to discuss appropriate (mouse) models for neurodegenerative diseases as well as to conceptualise sophisticated proteomics analyses strategies. Here, the topics of the meeting are summarised.

Evaluation of an in vitro toxicogenetic mouse model for hepatotoxicity

International Nuclear Information System (INIS)

Martinez, Stephanie M.; Bradford, Blair U.; Soldatow, Valerie Y.; Kosyk, Oksana; Sandot, Amelia; Witek, Rafal; Kaiser, Robert; Stewart, Todd; Amaral, Kirsten; Freeman, Kimberly; Black, Chris; LeCluyse, Edward L.; Ferguson, Stephen S.; Rusyn, Ivan

2010-01-01

Numerous studies support the fact that a genetically diverse mouse population may be useful as an animal model to understand and predict toxicity in humans. We hypothesized that cultures of hepatocytes obtained from a large panel of inbred mouse strains can produce data indicative of inter-individual differences in in vivo responses to hepato-toxicants. In order to test this hypothesis and establish whether in vitro studies using cultured hepatocytes from genetically distinct mouse strains are feasible, we aimed to determine whether viable cells may be isolated from different mouse inbred strains, evaluate the reproducibility of cell yield, viability and functionality over subsequent isolations, and assess the utility of the model for toxicity screening. Hepatocytes were isolated from 15 strains of mice (A/J, B6C3F1, BALB/cJ, C3H/HeJ, C57BL/6J, CAST/EiJ, DBA/2J, FVB/NJ, BALB/cByJ, AKR/J, MRL/MpJ, NOD/LtJ, NZW/LacJ, PWD/PhJ and WSB/EiJ males) and cultured for up to 7 days in traditional 2-dimensional culture. Cells from B6C3F1, C57BL/6J, and NOD/LtJ strains were treated with acetaminophen, WY-14,643 or rifampin and concentration-response effects on viability and function were established. Our data suggest that high yield and viability can be achieved across a panel of strains. Cell function and expression of key liver-specific genes of hepatocytes isolated from different strains and cultured under standardized conditions are comparable. Strain-specific responses to toxicant exposure have been observed in cultured hepatocytes and these experiments open new opportunities for further developments of in vitro models of hepatotoxicity in a genetically diverse population.

water alteration processes and kinetics of basaltic glasses, natural analogue of nuclear glasses

International Nuclear Information System (INIS)

Techer, I.; Advocat, Th.; Vernaz, E.; Lancelot, J.R.; Liotard, J.M.

1997-01-01

Dissolution experiments of a basaltic glass were carried out at 90 deg C for different reaction progresses. The initial dissolution rate was compared with values obtained for rhyolitic glass and the R7T7 nuclear glass. The activation energy was also determined by computing literature data. The results provide similar reactional mechanism for basaltic and nuclear glasses. Dissolution rates measured under saturation conditions were compared to theoretical dissolution rates. These ones were calculated using two kinetic models: the first rate equation is the Grambow's law which only takes into account ortho-silica acid activity; the second rate equation was proposed by Daux et al., where silica and aluminum are combined to formulate the affinity. The comparison between experimental and theoretical results point out that these two models are not appropriate to describe the alteration kinetic of basaltic glasses. (authors)

Thermodynamic and structural models compared with the initial dissolution rates of open-quotes SONclose quotes glass samples

International Nuclear Information System (INIS)

Tovena, I.; Advocat, T.; Ghaleb, D.; Vernaz, E.; Larche, F.

1994-01-01

The experimentally determined initial dissolution rate R 0 of nuclear glass was correlated with thermodynamic parameters and structural parameters. The initial corrosion rates of six open-quotes R7T7close quotes glass samples measured at 100 degrees C in a Soxhlet device were correlated with the glass free hydration energy and the glass formation enthalpy. These correlations were then tested with a group of 26 SON glasses selected for their wide diversity of compositions. The thermodynamic models provided a satisfactory approximation of the initial dissolution rate determined under Soxhlet conditions for SON glass samples that include up to 15 wt% of boron and some alumina. Conversely, these models are inaccurate if the boron concentration exceeds 15 wt% and the glass contains no alumina. Possible correlations between R 0 and structural parameters, such as the boron coordination number and the number of nonbridging oxygen atoms, were also investigated. The authors show that R 0 varies inversely with the number of 4-coordinate boron atoms; conversely, the results do not substantiate published reports of a correlation between R 0 and the number of nonbridging oxygen atoms

Waterlike glass polyamorphism in a monoatomic isotropic Jagla model.

Science.gov (United States)

Xu, Limei; Giovambattista, Nicolas; Buldyrev, Sergey V; Debenedetti, Pablo G; Stanley, H Eugene

2011-02-14

We perform discrete-event molecular dynamics simulations of a system of particles interacting with a spherically-symmetric (isotropic) two-scale Jagla pair potential characterized by a hard inner core, a linear repulsion at intermediate separations, and a weak attractive interaction at larger separations. This model system has been extensively studied due to its ability to reproduce many thermodynamic, dynamic, and structural anomalies of liquid water. The model is also interesting because: (i) it is very simple, being composed of isotropically interacting particles, (ii) it exhibits polyamorphism in the liquid phase, and (iii) its slow crystallization kinetics facilitate the study of glassy states. There is interest in the degree to which the known polyamorphism in glassy water may have parallels in liquid water. Motivated by parallels between the properties of the Jagla potential and those of water in the liquid state, we study the metastable phase diagram in the glass state. Specifically, we perform the computational analog of the protocols followed in the experimental studies of glassy water. We find that the Jagla potential calculations reproduce three key experimental features of glassy water: (i) the crystal-to-high-density amorphous solid (HDA) transformation upon isothermal compression, (ii) the low-density amorphous solid (LDA)-to-HDA transformation upon isothermal compression, and (iii) the HDA-to-very-high-density amorphous solid (VHDA) transformation upon isobaric annealing at high pressure. In addition, the HDA-to-LDA transformation upon isobaric heating, observed in water experiments, can only be reproduced in the Jagla model if a free surface is introduced in the simulation box. The HDA configurations obtained in cases (i) and (ii) are structurally indistinguishable, suggesting that both processes result in the same glass. With the present parametrization, the evolution of density with pressure or temperature is remarkably similar to the

Development of models and software for liquidus temperatures of glasses of HWVP products. Final report

International Nuclear Information System (INIS)

Hrma, P.R.; Vienna, J.D.; Pelton, A.D.

1996-03-01

In an earlier report [92 Pel] was described the development of software and thermodynamic databases for the calculation of liquidus temperatures of glasses of HWVP products containing the components SiO 2 -B 2 O 3 -Na 2 O-Li 2 O-CaO-MgO-Fe 2 O 3 -Al 2 O 3 -ZrO 2 -open-quotes othersclose quotes. The software package developed at that time consisted of the EQUILIB program of the F*A*C*T computer system with special input/output routines. Since then, Battelle has purchased the entire F*A*C*T computer system, and this fully replaces the earlier package. Furthermore, with the entire F*A*C*T system, additional calculations can be performed such as calculations at fixed O 2 , SO 2 etc. pressures, or graphing of output. Furthermore, the public F*A*C*T database of over 5000 gaseous species and condensed phases is now accessible. The private databases for the glass and crystalline phases were developed for Battelle by optimization of thermodynamic and phase diagram data. That is, all available data for 2- and 3-component sub-systems of the 9-component oxide system were collected, and parameters of model equations for the thermodynamic properties were found which best reproduce all the data. For representing the thermodynamic properties of the glass as a function of composition and temperature, the modified quasichemical model was used. This model was described in the earlier report [92 Pel] along with all the optimizations. With the model, it was possible to predict the thermodynamic properties of the 9-component glass, and thereby to calculate liquidus temperatures. Liquidus temperatures measured by Battelle for 123 CVS glass compositions were used to test the model and to refine the model by the addition of further parameters

A novel deep reactive ion etched (DRIE) glass micro-model for two-phase flow experiments.

Science.gov (United States)

Karadimitriou, N K; Joekar-Niasar, V; Hassanizadeh, S M; Kleingeld, P J; Pyrak-Nolte, L J

2012-09-21

In the last few decades, micro-models have become popular experimental tools for two-phase flow studies. In this work, the design and fabrication of an innovative, elongated, glass-etched micro-model with dimensions of 5 × 35 mm(2) and constant depth of 43 microns is described. This is the first time that a micro-model with such depth and dimensions has been etched in glass by using a dry etching technique. The micro-model was visualized by a novel setup that allowed us to monitor and record the distribution of fluids throughout the length of the micro-model continuously. Quasi-static drainage experiments were conducted in order to obtain equilibrium data points that relate capillary pressure to phase saturation. By measuring the flow rate of water through the flow network for known pressure gradients, the intrinsic permeability of the micro-model's flow network was also calculated. The experimental results were used to calibrate a pore-network model and test its validity. Finally, we show that glass-etched micro-models can be valuable tools in single and/or multi-phase flow studies and their applications.

Biology and therapy of inherited retinal degenerative disease: insights from mouse models

Directory of Open Access Journals (Sweden)

Shobi Veleri

2015-02-01

Full Text Available Retinal neurodegeneration associated with the dysfunction or death of photoreceptors is a major cause of incurable vision loss. Tremendous progress has been made over the last two decades in discovering genes and genetic defects that lead to retinal diseases. The primary focus has now shifted to uncovering disease mechanisms and designing treatment strategies, especially inspired by the successful application of gene therapy in some forms of congenital blindness in humans. Both spontaneous and laboratory-generated mouse mutants have been valuable for providing fundamental insights into normal retinal development and for deciphering disease pathology. Here, we provide a review of mouse models of human retinal degeneration, with a primary focus on diseases affecting photoreceptor function. We also describe models associated with retinal pigment epithelium dysfunction or synaptic abnormalities. Furthermore, we highlight the crucial role of mouse models in elucidating retinal and photoreceptor biology in health and disease, and in the assessment of novel therapeutic modalities, including gene- and stem-cell-based therapies, for retinal degenerative diseases.

Mouse models in liver cancer research: A review of current literature

Science.gov (United States)

Leenders, Martijn WH; Nijkamp, Maarten W; Rinkes, Inne HM Borel

2008-01-01

Primary liver cancer remains one of the most lethal malignancies worldwide. Due to differences in prevalence of etiological factors the incidence of primary liver cancer varies among the world, with a peak in East-Asia. As this disease is still lethal in most of the cases, research has to be done to improve our understanding of the disease, offering insights for possible treatment options. For this purpose, animal models are widely used, especially mouse models. In this review, we describe the different types of mouse models used in liver cancer research, with emphasis on genetically engineered mice used in this field. We focus on hepatocellular carcinoma (HCC), as this is by far the most common type of primary liver cancer, accounting for 70%-85% of cases. PMID:19058325

Chemical composition analysis and product consistency tests to support enhanced Hanford waste glass models. Results for the third set of high alumina outer layer matrix glasses

Energy Technology Data Exchange (ETDEWEB)

Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States)

2015-12-01

In this report, the Savannah River National Laboratory provides chemical analyses and Product Consistency Test (PCT) results for 14 simulated high level waste glasses fabricated by the Pacific Northwest National Laboratory. The results of these analyses will be used as part of efforts to revise or extend the validation regions of the current Hanford Waste Treatment and Immobilization Plant glass property models to cover a broader span of waste compositions. The measured chemical composition data are reported and compared with the targeted values for each component for each glass. All of the measured sums of oxides for the study glasses fell within the interval of 96.9 to 100.8 wt %, indicating recovery of all components. Comparisons of the targeted and measured chemical compositions showed that the measured values for the glasses met the targeted concentrations within 10% for those components present at more than 5 wt %. The PCT results were normalized to both the targeted and measured compositions of the study glasses. Several of the glasses exhibited increases in normalized concentrations (NCi) after the canister centerline cooled (CCC) heat treatment. Five of the glasses, after the CCC heat treatment, had NC_B values that exceeded that of the Environmental Assessment (EA) benchmark glass. These results can be combined with additional characterization, including X-ray diffraction, to determine the cause of the higher release rates.

Distinctive serum miRNA profile in mouse models of striated muscular pathologies.

Directory of Open Access Journals (Sweden)

Nicolas Vignier

Full Text Available Biomarkers are critically important for disease diagnosis and monitoring. In particular, close monitoring of disease evolution is eminently required for the evaluation of therapeutic treatments. Classical monitoring methods in muscular dystrophies are largely based on histological and molecular analyses of muscle biopsies. Such biopsies are invasive and therefore difficult to obtain. The serum protein creatine kinase is a useful biomarker, which is however not specific for a given pathology and correlates poorly with the severity or course of the muscular pathology. The aim of the present study was the systematic evaluation of serum microRNAs (miRNAs as biomarkers in striated muscle pathologies. Mouse models for five striated muscle pathologies were investigated: Duchenne muscular dystrophy (DMD, limb-girdle muscular dystrophy type 2D (LGMD2D, limb-girdle muscular dystrophy type 2C (LGMD2C, Emery-Dreifuss muscular dystrophy (EDMD and hypertrophic cardiomyopathy (HCM. Two-step RT-qPCR methodology was elaborated, using two different RT-qPCR miRNA quantification technologies. We identified miRNA modulation in the serum of all the five mouse models. The most highly dysregulated serum miRNAs were found to be commonly upregulated in DMD, LGMD2D and LGMD2C mouse models, which all exhibit massive destruction of striated muscle tissues. Some of these miRNAs were down rather than upregulated in the EDMD mice, a model without massive myofiber destruction. The dysregulated miRNAs identified in the HCM model were different, with the exception of one dysregulated miRNA common to all pathologies. Importantly, a specific and distinctive circulating miRNA profile was identified for each studied pathological mouse model. The differential expression of a few dysregulated miRNAs in the DMD mice was further evaluated in DMD patients, providing new candidates of circulating miRNA biomarkers for DMD.

A mouse model of mitochondrial complex III dysfunction induced by myxothiazol

Energy Technology Data Exchange (ETDEWEB)

Davoudi, Mina [Pediatrics, Department of Clinical Sciences, Lund, Lund University, Lund 22185 (Sweden); Kallijärvi, Jukka; Marjavaara, Sanna [Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki, 00014 (Finland); Kotarsky, Heike; Hansson, Eva [Pediatrics, Department of Clinical Sciences, Lund, Lund University, Lund 22185 (Sweden); Levéen, Per [Pediatrics, Department of Clinical Sciences, Lund, Lund University, Lund 22185 (Sweden); Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki, 00014 (Finland); Fellman, Vineta, E-mail: Vineta.Fellman@med.lu.se [Pediatrics, Department of Clinical Sciences, Lund, Lund University, Lund 22185 (Sweden); Folkhälsan Research Center, Biomedicum Helsinki, University of Helsinki, 00014 (Finland); Children’s Hospital, Helsinki University Hospital, University of Helsinki, Helsinki 00029 (Finland)

2014-04-18

Highlights: • Reversible chemical inhibition of complex III in wild type mouse. • Myxothiazol causes decreased complex III activity in mouse liver. • The model is useful for therapeutic trials to improve mitochondrial function. - Abstract: Myxothiazol is a respiratory chain complex III (CIII) inhibitor that binds to the ubiquinol oxidation site Qo of CIII. It blocks electron transfer from ubiquinol to cytochrome b and thus inhibits CIII activity. It has been utilized as a tool in studies of respiratory chain function in in vitro and cell culture models. We developed a mouse model of biochemically induced and reversible CIII inhibition using myxothiazol. We administered myxothiazol intraperitoneally at a dose of 0.56 mg/kg to C57Bl/J6 mice every 24 h and assessed CIII activity, histology, lipid content, supercomplex formation, and gene expression in the livers of the mice. A reversible CIII activity decrease to 50% of control value occurred at 2 h post-injection. At 74 h only minor histological changes in the liver were found, supercomplex formation was preserved and no significant changes in the expression of genes indicating hepatotoxicity or inflammation were found. Thus, myxothiazol-induced CIII inhibition can be induced in mice for four days in a row without overt hepatotoxicity or lethality. This model could be utilized in further studies of respiratory chain function and pharmacological approaches to mitochondrial hepatopathies.

Predicting the glass transition temperature of bioactive glasses from their molecular chemical composition.

Science.gov (United States)

Hill, Robert G; Brauer, Delia S

2011-10-01

A recently published paper (M.D. O'Donnell, Acta Biomaterialia 7 (2011) 2264-2269) suggests that it is possible to correlate the glass transition temperature (T(g)) of bioactive glasses with their molar composition, based on iterative least-squares fitting of published T(g) data. However, we show that the glass structure is an important parameter in determining T(g). Phase separation, local structural effects and components (intermediate oxides) which can switch their structural role in the glass network need to be taken into consideration, as they are likely to influence the glass transition temperature of bioactive glasses. Although the model suggested by O'Donnell works reasonably well for glasses within the composition range presented, it is oversimplified and fails for glasses outside certain compositional boundaries. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

The Mouse Lemur, a Genetic Model Organism for Primate Biology, Behavior, and Health.

Science.gov (United States)

Ezran, Camille; Karanewsky, Caitlin J; Pendleton, Jozeph L; Sholtz, Alex; Krasnow, Maya R; Willick, Jason; Razafindrakoto, Andriamahery; Zohdy, Sarah; Albertelli, Megan A; Krasnow, Mark A

2017-06-01

Systematic genetic studies of a handful of diverse organisms over the past 50 years have transformed our understanding of biology. However, many aspects of primate biology, behavior, and disease are absent or poorly modeled in any of the current genetic model organisms including mice. We surveyed the animal kingdom to find other animals with advantages similar to mice that might better exemplify primate biology, and identified mouse lemurs ( Microcebus spp.) as the outstanding candidate. Mouse lemurs are prosimian primates, roughly half the genetic distance between mice and humans. They are the smallest, fastest developing, and among the most prolific and abundant primates in the world, distributed throughout the island of Madagascar, many in separate breeding populations due to habitat destruction. Their physiology, behavior, and phylogeny have been studied for decades in laboratory colonies in Europe and in field studies in Malagasy rainforests, and a high quality reference genome sequence has recently been completed. To initiate a classical genetic approach, we developed a deep phenotyping protocol and have screened hundreds of laboratory and wild mouse lemurs for interesting phenotypes and begun mapping the underlying mutations, in collaboration with leading mouse lemur biologists. We also seek to establish a mouse lemur gene "knockout" library by sequencing the genomes of thousands of mouse lemurs to identify null alleles in most genes from the large pool of natural genetic variants. As part of this effort, we have begun a citizen science project in which students across Madagascar explore the remarkable biology around their schools, including longitudinal studies of the local mouse lemurs. We hope this work spawns a new model organism and cultivates a deep genetic understanding of primate biology and health. We also hope it establishes a new and ethical method of genetics that bridges biological, behavioral, medical, and conservation disciplines, while

Primary amines protect against retinal degeneration in mouse models of retinopathies.

Science.gov (United States)

Maeda, Akiko; Golczak, Marcin; Chen, Yu; Okano, Kiichiro; Kohno, Hideo; Shiose, Satomi; Ishikawa, Kaede; Harte, William; Palczewska, Grazyna; Maeda, Tadao; Palczewski, Krzysztof

2011-12-25

Vertebrate vision is initiated by photoisomerization of the visual pigment chromophore 11-cis-retinal and is maintained by continuous regeneration of this retinoid through a series of reactions termed the retinoid cycle. However, toxic side reaction products, especially those involving reactive aldehyde groups of the photoisomerized product, all-trans-retinal, can cause severe retinal pathology. Here we lowered peak concentrations of free all-trans-retinal with primary amine-containing Food and Drug Administration (FDA)-approved drugs that did not inhibit chromophore regeneration in mouse models of retinal degeneration. Schiff base adducts between all-trans-retinal and these amines were identified by MS. Adducts were observed in mouse eyes only when an experimental drug protected the retina from degeneration in both short-term and long-term treatment experiments. This study demonstrates a molecular basis of all-trans-retinal-induced retinal pathology and identifies an assemblage of FDA-approved compounds with protective effects against this pathology in a mouse model that shows features of Stargardt's disease and age-related retinal degeneration.

Modeling size effects on fatigue life of a zirconium-based bulk metallic glass under bending

International Nuclear Information System (INIS)

Yuan Tao; Wang Gongyao; Feng Qingming; Liaw, Peter K.; Yokoyama, Yoshihiko; Inoue, Akihisa

2013-01-01

A size effect on the fatigue-life cycles of a Zr 50 Cu 30 Al 10 Ni 10 (at.%) bulk metallic glass has been observed in the four-point-bending fatigue experiment. Under the same bending-stress condition, large-sized samples tend to exhibit longer fatigue lives than small-sized samples. This size effect on the fatigue life cannot be satisfactorily explained by the flaw-based Weibull theories. Based on the experimental results, this study explores possible approaches to modeling the size effects on the bending-fatigue life of bulk metallic glasses, and proposes two fatigue-life models based on the Weibull distribution. The first model assumes, empirically, log-linear effects of the sample thickness on the Weibull parameters. The second model incorporates the mechanistic knowledge of the fatigue behavior of metallic glasses, and assumes that the shear-band density, instead of the flaw density, has significant influence on the bending fatigue-life cycles. Promising predictive results provide evidence of the potential validity of the models and their assumptions.

Antibacterial and Antifungal Activity of ZnO Containing Glasses.

Science.gov (United States)

Esteban-Tejeda, Leticia; Prado, Catuxa; Cabal, Belén; Sanz, Jesús; Torrecillas, Ramón; Moya, José Serafín

2015-01-01

A new family of non-toxic biocides based on low melting point (1250°C) transparent glasses with high content of ZnO (15-40wt%) belonging to the miscibility region of the B2O3-SiO2-Na2O-ZnO system has been developed. These glasses have shown an excellent biocide activity (logarithmic reduction >3) against Gram- (E. coli), Gram+ (S. aureus) and yeast (C. krusei); they are chemically stable in different media (distilled water, sea-like water, LB and DMEN media) as well as biocompatible. The cytotoxicity was evaluated by the Neutral Red Uptake using NIH-3T3 (mouse embryonic fibroblast cells) and the cell viability was >80%. These new glasses can be considered in several and important applications in the field of inorganic non-toxic biocide agents such as medical implants, surgical equipment, protective apparels in hospitals, water purifications systems, food packaging, food storages or textiles.

The Oak Ridge Polycystic Kidney mouse: modeling ciliopathies of mice and men.

Energy Technology Data Exchange (ETDEWEB)

Lehman, J M [University of Alabama, Birmingham; Michaud III, Edward J [ORNL; Schoeb, T [University of Alabama, Birmingham; Aydin Son, Yesim [University of Tennessee, Knoxville (UTK); Miller, M [University of Alabama, Birmingham; Yoder, Bradley [University of Alabama, Birmingham

2008-08-01

The Oak Ridge Polycystic Kidney (ORPK) mouse was described nearly 14 years ago as a model for human recessive polycystic kidney disease. The ORPK mouse arose through integration of a transgene into an intron of the Ift88 gene resulting in a hypomorphic allele (Ift88Tg737Rpw). The Ift88Tg737Rpw mutation impairs intraflagellar transport (IFT), a process required for assembly of motile and immotile cilia. Historically, the primary immotile cilium was thought to have minimal importance for human health; however, a rapidly expanding number of human disorders have now been attributed to ciliary defects. Importantly, many of these phenotypes are present and can be analyzed using the ORPK mouse. In this review, we highlight the research conducted using the OPRK mouse and the phenotypes shared with human cilia disorders. Furthermore, we describe an additional follicular dysplasia phenotype in the ORPK mouse, which alongside the ectodermal dysplasias seen in human Ellis-van Creveld and Sensenbrenner's syndromes, suggests an unappreciated role for primary cilia in the skin and hair follicle.

USING OF MOUSE MODEL TO ANALYZE IMMUNE RESPONSE TO INFECTIOUS PATHOGENS BY THE METHODS OF CLASSICAL GENETICS

Directory of Open Access Journals (Sweden)

A. Poltorak

2011-01-01

Full Text Available Abstract. Identification and studying of numerous functions of all genes of the human beings is one of the main objects of modern biological science. Due to high level of homology between mouse and human genomes the important role to reach above mentioned goal belongs to the mouse model which using in the classical genetics increase in connection with appearance of different inbred mouse lines. For instance, the differences in immune response to infectious pathogens in various mouse lines were used many times to determine immunologically competent genes. That is why the contribution of mouse model in understanding of the mechanisms of immune response to infectious pathogens is difficult to overestimate. In the current review some of the most successful and well known examples of mouse using in studies of anti-infectious response are described.

Cholinergic anti-inflammatory pathway in the non-obese diabetic mouse model

NARCIS (Netherlands)

Koopman, F. A.; Vosters, J. L.; Roescher, N.; Broekstra, N.; Tak, P. P.; Vervoordeldonk, M. J.

2015-01-01

Activation of the cholinergic anti-inflammatory pathway (CAP) has been shown to reduce inflammation in animal models, while abrogation of the pathway increases inflammation. We investigated whether modulation of CAP influences inflammation in the non-obese diabetic (NOD) mouse model for Sjögren's

THE ANALYSIS OF FLAT GLASS EXPORTS FOR ROMANIA USING THE GRAVITY MODEL

Directory of Open Access Journals (Sweden)

Draghescu Florin

2015-07-01

Full Text Available The intense international competition and reduced rates of economics growth force the companies at dynamic and appropriate strategies to address internal and external market. The manufacturing industry from Romania has competitive advantages defined by tradition, qualified labour force, indigenous raw materials, and its products serve various industries – construction, automotive, food – that is expected to experience a future sustained development. With approximately 2,500 employees, the glassware sector from Romania is part of the manufacturing industry which has constantly decreased in the last 25 years. Romania has a long tradition in the glassware sector and remains a strategic player in the region being integrated in the global flows from the industry. Geographical orientation of Romanian trade of flat glass for export is analyzed using the gravity model. The purpose of this article is to determine the essential factors of flat glass export level from Romania to states with which has commercial partnerships using both a gravity static model, but also a gravity dynamic model – a common model in the literature, used to analyze the trade flows between world countries or polarization strength of cities and commercial centres. The empirical results of both models have shown that the gravity attraction of local and destination economies, transport costs – measured by the distances between capitals and lack of common border –, language interconnectivity, and also belonging to the BSEC (Organization of the Black Sea Economic Cooperation are the most important factors affecting the Romanian exports of the flat glass.

Development of a unilaterally-lesioned 6-OHDA mouse model of Parkinson's disease.

Science.gov (United States)

Thiele, Sherri L; Warre, Ruth; Nash, Joanne E

2012-02-14

The unilaterally lesioned 6-hyroxydopamine (6-OHDA)-lesioned rat model of Parkinson's disease (PD) has proved to be invaluable in advancing our understanding of the mechanisms underlying parkinsonian symptoms, since it recapitulates the changes in basal ganglia circuitry and pharmacology observed in parkinsonian patients(1-4). However, the precise cellular and molecular changes occurring at cortico-striatal synapses of the output pathways within the striatum, which is the major input region of the basal ganglia remain elusive, and this is believed to be site where pathological abnormalities underlying parkinsonian symptoms arise(3,5). In PD, understanding the mechanisms underlying changes in basal ganglia circuitry following degeneration of the nigro-striatal pathway has been greatly advanced by the development of bacterial artificial chromosome (BAC) mice over-expressing green fluorescent proteins driven by promoters specific for the two striatal output pathways (direct pathway: eGFP-D1; indirect pathway: eGFP-D2 and eGFP-A2a)(8), allowing them to be studied in isolation. For example, recent studies have suggested that there are pathological changes in synaptic plasticity in parkinsonian mice(9,10). However, these studies utilised juvenile mice and acute models of parkinsonism. It is unclear whether the changes described in adult rats with stable 6-OHDA lesions also occur in these models. Other groups have attempted to generate a stable unilaterally-lesioned 6-OHDA adult mouse model of PD by lesioning the medial forebrain bundle (MFB), unfortunately, the mortality rate in this study was extremely high, with only 14% surviving the surgery for 21 days or longer(11). More recent studies have generated intra-nigral lesions with both a low mortality rate >80% loss of dopaminergic neurons, however expression of L-DOPA induced dyskinesia(11,12,13,14) was variable in these studies. Another well established mouse model of PD is the MPTP-lesioned mouse(15). Whilst this

Structure, biodegradation behavior and cytotoxicity of alkali-containing alkaline-earth phosphosilicate glasses.

Science.gov (United States)

Kansal, Ishu; Reddy, AlluAmarnath; Muñoz, Francisco; Choi, Seong-Jun; Kim, Hae-Won; Tulyaganov, Dilshat U; Ferreira, José M F

2014-11-01

We report on the effect of sodium on the structure, chemical degradation and bioactivity of glasses in the CaO-MgO-SiO2-P2O5-CaF2 system. The (29)Si and (31)P magic angle spinning-nuclear magnetic resonance spectroscopy of melt-quenched glasses with varying Na2O/MgO ratios exhibit a silicate glass network with the dominance of Q(2)(Si) units and phosphorus mainly forming orthophosphate species. Sodium incorporation in the glasses did not induce a significant structural change in the silicate network, while it did influence the phosphate environment due to its lower ionic field strength in comparison with that of magnesium. The apatite forming ability of glasses has been investigated by immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1h and 7 days while their chemical degradation has been studied in Tris-HCl in accordance with ISO-10993-14. Increasing Na(+)/Mg(2+) ratio caused a decrease in the chemical durability of glasses and in the apatite forming ability especially during initial steps of interaction between glass and SBF solution. The cellular responses were observed in vitro on bulk glass samples using mouse-derived pre-osteoblastic MC3T3-E1 cell line. The preliminary study suggested that the increasing alkali-concentration in glasses led to cytotoxicity in the cell culture medium. Copyright © 2014 Elsevier B.V. All rights reserved.

2014 Enhanced LAW Glass Property-Composition Models, Phase 2

Energy Technology Data Exchange (ETDEWEB)

Muller, Isabelle [The Catholic Univ. of America, Washington, DC (United States); Pegg, Ian L. [The Catholic Univ. of America, Washington, DC (United States); Joseph, Innocent [Energy Solutions, Salt Lake City, UT (United States); Gilbo, Konstantin [The Catholic Univ. of America, Washington, DC (United States)

2015-10-28

This report describes the results of testing specified by the Enhanced LAW Glass Property-Composition Models, VSL-13T3050-1, Rev. 0 Test Plan. The work was performed in compliance with the quality assurance requirements specified in the Test Plan. Results required by the Test Plan are reported. The te4st results and this report have been reviewed for correctness, technical adequacy, completeness, and accuracy.

A New Mouse Model That Spontaneously Develops Chronic Liver Inflammation and Fibrosis.

Directory of Open Access Journals (Sweden)

Nina Fransén-Pettersson

Full Text Available Here we characterize a new animal model that spontaneously develops chronic inflammation and fibrosis in multiple organs, the non-obese diabetic inflammation and fibrosis (N-IF mouse. In the liver, the N-IF mouse displays inflammation and fibrosis particularly evident around portal tracts and central veins and accompanied with evidence of abnormal intrahepatic bile ducts. The extensive cellular infiltration consists mainly of macrophages, granulocytes, particularly eosinophils, and mast cells. This inflammatory syndrome is mediated by a transgenic population of natural killer T cells (NKT induced in an immunodeficient NOD genetic background. The disease is transferrable to immunodeficient recipients, while polyclonal T cells from unaffected syngeneic donors can inhibit the disease phenotype. Because of the fibrotic component, early on-set, spontaneous nature and reproducibility, this novel mouse model provides a unique tool to gain further insight into the underlying mechanisms mediating transformation of chronic inflammation into fibrosis and to evaluate intervention protocols for treating conditions of fibrotic disorders.

Modelling and experimental contrast of the mechanical behaviour of structural laminated glass

Directory of Open Access Journals (Sweden)

Sanz-Ablanedo, E.

2010-12-01

Full Text Available This paper presents a numerical simulation of the mechanical behaviour of laminated glass plates (glass- PVB-glass and its experimental verification. The viscoelastic characterization of the intermediate layer of PVB has been done by means of stress relaxation tests at various temperatures. The consideration of PVB as a viscoelastic material permits to analyze the real response of the structural element of laminated glass under time variations of temperature, of application of loading, of stress state, etc. Displacements obtained with the numerical analysis have been verified experimentally with laminated glass plates under lateral load using close range photogrammetry and dial gauges indicators. The analysis of results confirms the time dependent behaviour of the glass-PVB-glass laminate and suggests the validity of the proposed model.

Este trabajo presenta la simulación numérica del comportamiento mecánico de placas de vidrio laminado (vidrio-PVB-vidrio y su comprobación experimental. La caracterización viscoelástica de la lámina intermedia de PVB se ha realizado mediante ensayos de relajación de tensiones a diversas temperaturas. La consideración del PVB como material viscoelástico permite analizar la respuesta real del elemento estructural de vidrio laminado ante variaciones en el tiempo de la temperatura, de la velocidad de aplicación de las cargas, del estado tensional, etc. Los desplazamientos obtenidos numéricamente han sido contrastados experimentalmente en placas de vidrio laminado sometidas a carga lateral mediante fotogrametría de objeto cercano y relojes comparadores. Del análisis de los resultados se confirma el comportamiento variable en el tiempo del conjunto vidrio-PVB-vidrio y se deduce la validez de la modelización propuesta.

Structure of Se-Te glasses studied using neutron, X-ray diffraction and reverse Monte Carlo modelling

Energy Technology Data Exchange (ETDEWEB)

Itoh, Keiji, E-mail: itoh@okayama-u.ac.jp [Graduate School of Education, Okayama University, Tsushima-naka, Okayama 700-8530 (Japan); Research Reactor Institute, Kyoto University, Kumatori, Osaka 590-0494 (Japan)

2017-02-15

Pulsed neutron diffraction and synchrotron X-ray diffraction measurements were performed on Se{sub 100-x}Te{sub x} bulk glasses with x=10, 20, 30 and 40. The coordination numbers obtained from the diffraction results demonstrate that Se and Te atoms are twofold coordinated and the glass structure is formed by the chain network. The three-dimensional structure model for Se{sub 60}Te{sub 40} glass obtained by using reverse Monte Carlo modelling shows that the alternating arrangements of Se and Te atoms compose the major part of the chain clusters but several other fragments such as Se{sub n} chains and Te-Te dimers are also present in large numbers. The chain clusters have geometrically disordered forms and the interchain atomic order is different from those in the crystal structures of trigonal Se and trigonal Te. - Graphical abstract: Coordination environment in Se{sub 60}Te{sub 40} glass.

Dmdmdx/Largemyd: a new mouse model of neuromuscular diseases useful for studying physiopathological mechanisms and testing therapies

Directory of Open Access Journals (Sweden)

Poliana C. M. Martins

2013-09-01

Although muscular dystrophies are among the most common human genetic disorders, there are few treatment options available. Animal models have become increasingly important for testing new therapies prior to entering human clinical trials. The Dmdmdx mouse is the most widely used animal model for Duchenne muscular dystrophy (DMD, presenting the same molecular and protein defect as seen in humans with the disease. However, this mouse is not useful for clinical trials because of its very mild phenotype. The mouse model for congenital myodystrophy type 1D, Largemyd, harbors a mutation in the glycosyltransferase Large gene and displays a severe phenotype. To help elucidate the role of the proteins dystrophin and LARGE in the organization of the dystrophin-glycoprotein complex in muscle sarcolemma, we generated double-mutant mice for the dystrophin and LARGE proteins. The new Dmdmdx/Largemyd mouse model is viable and shows a severe phenotype that is associated with the lack of dystrophin in muscle. We tested the usefulness of our new mouse model for cell therapy by systemically injecting them with normal murine mesenchymal adipose stem cells (mASCs. We verified that the mASCs were hosted in the dystrophic muscle. The new mouse model has proven to be very useful for the study of several other therapies, because injected cells can be screened both through DNA and protein analysis. Study of its substantial muscle weakness will also be very informative in the evaluation of functional benefits of these therapies.

Towards a mouse model of depression : a psychoneuroendocrine approach

NARCIS (Netherlands)

Dalm, Sergiu

2012-01-01

Chronic stress is considered a vulnerability factor for depression. A key symptom is anhedonia; a reduced response to positive stimuli. Drugs are effective for only 20-40% of the patients and new drugs are urgently needed. The objective of the research was to develop a mouse model of depression that

Sparse Statistical Deformation Model for the Analysis of Craniofacial Malformations in the Crouzon Mouse

DEFF Research Database (Denmark)

Ólafsdóttir, Hildur; Hansen, Michael Sass; Sjöstrand, Karl

2007-01-01

Crouzon syndrome is characterised by the premature fusion of cranial sutures. Recently the first genetic Crouzon mouse model was generated. In this study, Micro CT skull scannings of wild-type mice and Crouzon mice were investigated. Using nonrigid registration, a wild-type mouse atlas was built...

Longitudinal Multiplexed Measurement of Quantitative Proteomic Signatures in Mouse Lymphoma Models Using Magneto-Nanosensors.

Science.gov (United States)

Lee, Jung-Rok; Appelmann, Iris; Miething, Cornelius; Shultz, Tyler O; Ruderman, Daniel; Kim, Dokyoon; Mallick, Parag; Lowe, Scott W; Wang, Shan X

2018-01-01

Cancer proteomics is the manifestation of relevant biological processes in cancer development. Thus, it reflects the activities of tumor cells, host-tumor interactions, and systemic responses to cancer therapy. To understand the causal effects of tumorigenesis or therapeutic intervention, longitudinal studies are greatly needed. However, most of the conventional mouse experiments are unlikely to accommodate frequent collection of serum samples with a large enough volume for multiple protein assays towards single-object analysis. Here, we present a technique based on magneto-nanosensors to longitudinally monitor the protein profiles in individual mice of lymphoma models using a small volume of a sample for multiplex assays. Methods: Drug-sensitive and -resistant cancer cell lines were used to develop the mouse models that render different outcomes upon the drug treatment. Two groups of mice were inoculated with each cell line, and treated with either cyclophosphamide or vehicle solution. Serum samples taken longitudinally from each mouse in the groups were measured with 6-plex magneto-nanosensor cytokine assays. To find the origin of IL-6, experiments were performed using IL-6 knock-out mice. Results: The differences in serum IL-6 and GCSF levels between the drug-treated and untreated groups were revealed by the magneto-nanosensor measurement on individual mice. Using the multiplex assays and mouse models, we found that IL-6 is secreted by the host in the presence of tumor cells upon the drug treatment. Conclusion: The multiplex magneto-nanosensor assays enable longitudinal proteomic studies on mouse tumor models to understand tumor development and therapy mechanisms more precisely within a single biological object.

Ion exchange for glass strengthening

International Nuclear Information System (INIS)

Gy, Rene

2008-01-01

This paper presents a short overview of silicate glass strengthening by exchange of alkali ions in a molten salt, below the glass transition temperature (chemical tempering). The physics of alkali inter-diffusion is briefly explained and the main parameters of the process, which control the glass reinforcement, are reviewed. Methods for characterizing the obtained residual stress state and the strengthening are described, along with the simplified modelling of the stress build-up. The fragmentation of chemically tempered glass is discussed. The concept of engineered stress profile glass is presented, and finally, the effect of glass and salt compositions is overviewed

Mouse neuroblastoma cell based model and the effect of epileptic events on calcium oscillations and neural spikes

Science.gov (United States)

Kim, Suhwan; Baek, Juyeong; Jung, Unsang; Lee, Sangwon; Jung, Woonggyu; Kim, Jeehyun; Kang, Shinwon

2013-05-01

Recently, Mouse neuroblastoma cells are considered as an attractive model for the study of human neurological and prion diseases, and intensively used as a model system in different areas. Among those areas, differentiation of neuro2a (N2A) cells, receptor mediated ion current, and glutamate induced physiological response are actively investigated. The reason for the interest to mouse neuroblastoma N2A cells is that they have a fast growing rate than other cells in neural origin with a few another advantages. This study evaluated the calcium oscillations and neural spikes recording of mouse neuroblastoma N2A cells in an epileptic condition. Based on our observation of neural spikes in mouse N2A cell with our proposed imaging modality, we report that mouse neuroblastoma N2A cells can be an important model related to epileptic activity studies. It is concluded that the mouse neuroblastoma N2A cells produce the epileptic spikes in vitro in the same way as produced by the neurons or the astrocytes. This evidence advocates the increased and strong level of neurotransmitters release by enhancement in free calcium using the 4-aminopyridine which causes the mouse neuroblastoma N2A cells to produce the epileptic spikes and calcium oscillation.

Ab Initio Modeling of Structure and Properties of Single and Mixed Alkali Silicate Glasses.

Science.gov (United States)

Baral, Khagendra; Li, Aize; Ching, Wai-Yim

2017-10-12

A density functional theory (DFT)-based ab initio molecular dynamics (AIMD) has been applied to simulate models of single and mixed alkali silicate glasses with two different molar concentrations of alkali oxides. The structural environments and spatial distributions of alkali ions in the 10 simulated models with 20% and 30% of Li, Na, K and equal proportions of Li-Na and Na-K are studied in detail for subtle variations among the models. Quantum mechanical calculations of electronic structures, interatomic bonding, and mechanical and optical properties are carried out for each of the models, and the results are compared with available experimental observation and other simulations. The calculated results are in good agreement with the experimental data. We have used the novel concept of using the total bond order density (TBOD), a quantum mechanical metric, to characterize internal cohesion in these glass models. The mixed alkali effect (MAE) is visible in the bulk mechanical properties but not obvious in other physical properties studied in this paper. We show that Li doping deviates from expected trend due to the much stronger Li-O bonding than those of Na and K doping. The approach used in this study is in contrast with current studies in alkali-doped silicate glasses based only on geometric characterizations.

[Effect of topical application of a recombinant adenovirus carrying promyelocytic leukemia gene in a psoriasis-like mouse model].

Science.gov (United States)

Wang, Qiongyu; Zhang, Aijun; Ma, Huiqun; Wang, Shijie; Ma, Yunyun; Zou, Xingwei; Li, Ruilian

2013-03-01

To investigate the effects of topical treatment with adenovirus-mediated promyelocytic leukemia gene (PML) gene in a psoriasis-like mouse model. The effect of adenovirus-mediated PML gene on the granular layer of mouse tail scale epidermis and epithelial mitosis were observed on longitudinal histological sections prepared from the tail skin and vaginal epithelium of the mice. Adenovirus-mediated PML gene significantly inhibited mitosis of mouse vaginal epithelial cells and promoted the formation of granular layer in mouse tail scale epidermis. The therapeutic effect of PML gene in the psoriasis-like mouse model may be associated with increased granular cells and suppressed epidemic cell proliferation.

Fractalkine overexpression suppresses tau pathology in a mouse model of tauopathy.

Science.gov (United States)

Nash, Kevin R; Lee, Daniel C; Hunt, Jerry B; Morganti, Josh M; Selenica, Maj-Linda; Moran, Peter; Reid, Patrick; Brownlow, Milene; Guang-Yu Yang, Clement; Savalia, Miloni; Gemma, Carmelina; Bickford, Paula C; Gordon, Marcia N; Morgan, David

2013-06-01

Alzheimer's disease is characterized by amyloid plaques, neurofibrillary tangles, glial activation, and neurodegeneration. In mouse models, inflammatory activation of microglia accelerates tau pathology. The chemokine fractalkine serves as an endogenous neuronal modulator to quell microglial activation. Experiments with fractalkine receptor null mice suggest that fractalkine signaling diminishes tau pathology, but exacerbates amyloid pathology. Consistent with this outcome, we report here that soluble fractalkine overexpression using adeno-associated viral vectors significantly reduced tau pathology in the rTg4510 mouse model of tau deposition. Furthermore, this treatment reduced microglial activation and appeared to prevent neurodegeneration normally found in this model. However, in contrast to studies with fractalkine receptor null mice, parallel studies in an APP/PS1 model found no effect of increased fractalkine signaling on amyloid deposition. These data argue that agonism at fractalkine receptors might be an excellent target for therapeutic intervention in tauopathies, including those associated with amyloid deposition. Copyright © 2013 Elsevier Inc. All rights reserved.

Helium behaviour in nuclear glasses

International Nuclear Information System (INIS)

Fares, T.

2011-01-01

The present thesis focuses on the study of helium behavior in R7T7 nuclear waste glass. Helium is generated by the minor actinides alpha decays incorporated in the glass matrix. Therefore, four types of materials were used in this work. These are non radioactive R7T7 glasses saturated with helium under pressure, glasses implanted with 3 He + ions, glasses doped with curium and glasses irradiated in nuclear reactor. The study of helium solubility in saturated R7T7 glass has shown that helium atoms are inserted in the glass free volume. The results yielded a solubility of about 10 16 at. cm -3 atm. -1 . The incorporation limit of helium in this type of glass has been determined; its value amounted to about 2*10 21 at. cm -3 , corresponding to 2.5 at.%. Diffusion studies have shown that the helium migration is controlled by the single population dissolved in the glass free volume. An ideal diffusion model was used to simulate the helium release data which allowed to determine diffusion coefficients obeying to the following Arrhenius law: D = D 0 exp(-E a /kBT), where D 0 = 2.2*10 -2 and 5.4*10 -3 cm 2 s -1 and E a = 0.61 eV for the helium saturated and the curium doped glass respectively. These results reflect a thermally activated diffusion mechanism which seems to be not influenced by the glass radiation damage and helium concentrations studied in the present work (up to 8*10 19 at. g -1 , corresponding to 0.1 at.%). Characterizations of the macroscopic, structural and microstructural properties of glasses irradiated in nuclear reactor did not reveal any impact associated with the presence of helium at high concentrations. The observed modifications i.e. a swelling of 0.7 %, a decrease in hardness by 38 %, an increase between 8 and 34 % of the fracture toughness and a stabilization of the glass structure under irradiation, were attributed to the glass nuclear damage induced by the irradiation in reactor. Characterizations by SEM and TEM of R7T7 glasses implanted

Construction of a mouse model of factor VIII deficiency by gene targeting

Energy Technology Data Exchange (ETDEWEB)

Bi, L.; Lawler, A.; Gearhart, J. [Univ. of Pennsylvania School of Medicine, Philadelphia, PA (United States)] [and others

1994-09-01

To develop a small animal model of hemophilia A for gene therapy experiments, we set out to construct a mouse model for factor VIII deficiency by gene targeting. First, we screened a mouse liver cDNA library using a human FVIII cDNA probe. We cloned a 2.6 Kb partial mouse factor VIII cDNA which extends from 800 base pairs of the 3{prime} end of exon 14 to the 5{prime} end of exon 26. A mouse genomic library made from strain 129 was then screened to obtain genomic fragments covering the exons desired for homologous recombination. Two genomic clones were obtained, and one covering exon 15 through 22 was used for gene targeting. To make gene targeting constructs, a 5.8 Kb genomic DNA fragment covering exons 15 to 19 of the mouse FVIII gene was subcloned, and the neo expression cassette was inserted into exons 16 and 17 separately by different strategies. These two constructs were named MFVIIIC-16 and MFVIIIC-17. The constructs were linearized and transfected into strain 129 mouse ES cells by electroporation. Factor VIII gene-knockout ES cell lines were selected by G-418 and screened by genomic Southern blots. Eight exon 16 targeted cell lines and five exon 17 targeted cell lines were obtained. Three cell lines from each construct were injected into blastocysts and surgically transferred into foster mothers. Multiple chimeric mice with 70-90% hair color derived from the ES-cell genotype were seen with both constructs. Germ line transmission of the ES-cell genotype has been obtained for the MFVIIIC-16 construct, and multiple hemophilia A carrier females have been identified. Factor VIII-deficient males will be conceived soon.

Spin-glass-like transition in the majority-vote model with anticonformists

Science.gov (United States)

Krawiecki, Andrzej

2018-03-01

Majority-vote model on scale-free networks and random graphs is investigated in which a randomly chosen fraction p of agents (called anticonformists) follows an antiferromagnetic update rule, i.e., they assume, with probability governed by a parameter q (0 transition from a disordered (paramagnetic) state to a spin-glass-like state, characterized by a non-zero value of the spin-glass order parameter measuring the overlap of agents' opinions in two replicas of the system, and simultaneously by the magnetization close to zero. In the case of the model on scale-free networks the critical value of the parameter q weakly depends on the details of the degree distribution. As p is decreased, the critical value of q falls quickly to zero and only the disordered phase is observed. On the other hand, for p close to zero for decreasing q the usual ferromagnetic transition is observed.

Riluzole does not improve lifespan or motor function in three ALS mouse models.

Science.gov (United States)

Hogg, Marion C; Halang, Luise; Woods, Ina; Coughlan, Karen S; Prehn, Jochen H M

2017-12-08

Riluzole is the most widespread therapeutic for treatment of the progressive degenerative disease amyotrophic lateral sclerosis (ALS). Riluzole gained FDA approval in 1995 before the development of ALS mouse models. We assessed riluzole in three transgenic ALS mouse models: the SOD1 G93A model, the TDP-43 A315T model, and the recently developed FUS (1-359) model. Age, sex and litter-matched mice were treated with riluzole (22 mg/kg) in drinking water or vehicle (DMSO) from symptom onset. Lifespan was assessed and motor function tests were carried out twice weekly to determine whether riluzole slowed disease progression. Riluzole treatment had no significant benefit on lifespan in any of the ALS mouse models tested. Riluzole had no significant impact on decline in motor performance in the FUS (1-359) and SOD1 G93A transgenic mice as assessed by Rotarod and stride length analysis. Riluzole is widely prescribed for ALS patients despite questions surrounding its efficacy. Our data suggest that if riluzole was identified as a therapeutic candidate today it would not progress past pre-clinical assessment. This raises questions about the standards used in pre-clinical assessment of therapeutic candidates for the treatment of ALS.

Thermodynamical modeling of nuclear glasses: coexistence of amorphous phases

International Nuclear Information System (INIS)

Adjanor, G.

2007-11-01

Investigating the stability of borosilicate glasses used in the nuclear industry with respect to phase separation requires to estimate the Gibbs free energies of the various phases appearing in the material. In simulation, using current computational resources, a direct state-sampling of a glassy system with respect to its ensemble statistics is not ergodic and the estimated ensemble averages are not reliable. Our approach consists in generating, at a given cooling rate, a series of quenches, or paths connecting states of the liquid to states of the glass, and then in taking into account the probability to generate the paths leading to the different glassy states in ensembles averages. In this way, we introduce a path ensemble formalism and calculate a Landau free energy associated to a glassy meta-basin. This method was validated by accurately mapping the free energy landscape of a 38-atom glassy cluster. We then applied this approach to the calculation of the Gibbs free energies of binary amorphous Lennard-Jones alloys, and checked the correlation between the observed tendencies to order or to phase separate and the computed Gibbs free energies. We finally computed the driving force to phase separation in a simplified three-oxide nuclear glass modeled by a Born-Mayer-Huggins potential that includes a three-body term, and we compared the estimated quantities to the available experimental data. (author)

Genetically engineered mouse models of craniopharyngioma: an opportunity for therapy development and understanding of tumor biology.

Science.gov (United States)

Apps, John Richard; Martinez-Barbera, Juan Pedro

2017-05-01

Adamantinomatous craniopharyngioma (ACP) is the commonest tumor of the sellar region in childhood. Two genetically engineered mouse models have been developed and are giving valuable insights into ACP biology. These models have identified novel pathways activated in tumors, revealed an important function of paracrine signalling and extended conventional theories about the role of organ-specific stem cells in tumorigenesis. In this review, we summarize these mouse models, what has been learnt, their limitations and open questions for future research. We then discussed how these mouse models may be used to test novel therapeutics against potentially targetable pathways recently identified in human ACP. © 2017 The Authors. Brain Pathology published by John Wiley & Sons Ltd on behalf of International Society of Neuropathology.

Manifestation of Non-Alcoholic Fatty Liver Disease/Non-Alcoholic Steatohepatitis in Different Dietary Mouse Models

Directory of Open Access Journals (Sweden)

Vera HI Fengler

2016-05-01

Full Text Available Non-alcoholic fatty liver disease (NAFLD and non-alcoholic steatohepatitis (NASH, which are usually associated with obesity and metabolic syndrome, are considerable health and economic issues due to the rapid increase of their prevalence in Western society. Histologically, the diseases are characterised by steatosis, hepatic inflammation, and if further progressed, fibrosis. Dietary-induced mouse models are widely used in investigations of the development and progression of NAFLD and NASH; these models attempt to mimic the histological and metabolic features of the human diseases. However, the majority of dietary mouse models fail to reflect the whole pathophysiological spectrum of NAFLD and NASH. Some models exhibit histological features similar to those seen in humans while lacking the metabolic context, while others resemble the metabolic conditions leading to NAFLD in humans but fail to mimic the whole histological spectrum, including progression from steatosis to liver fibrosis, and thus fail to mimic NASH. This review summarises the advantages and disadvantages of the different dietary-induced mouse models of NAFLD and NASH, with a focus on the genetic background of several commonly used wild-type mouse strains as well as gender and age, which influence the development and progression of these liver diseases.

Mouse Model Resources for Vision Research

Directory of Open Access Journals (Sweden)

Jungyeon Won

2011-01-01

Full Text Available The need for mouse models, with their well-developed genetics and similarity to human physiology and anatomy, is clear and their central role in furthering our understanding of human disease is readily apparent in the literature. Mice carrying mutations that alter developmental pathways or cellular function provide model systems for analyzing defects in comparable human disorders and for testing therapeutic strategies. Mutant mice also provide reproducible, experimental systems for elucidating pathways of normal development and function. Two programs, the Eye Mutant Resource and the Translational Vision Research Models, focused on providing such models to the vision research community are described herein. Over 100 mutant lines from the Eye Mutant Resource and 60 mutant lines from the Translational Vision Research Models have been developed. The ocular diseases of the mutant lines include a wide range of phenotypes, including cataracts, retinal dysplasia and degeneration, and abnormal blood vessel formation. The mutations in disease genes have been mapped and in some cases identified by direct sequencing. Here, we report 3 novel alleles of Crxtvrm65, Rp1tvrm64, and Rpe65tvrm148 as successful examples of the TVRM program, that closely resemble previously reported knockout models.

Modeling the Onset of Phase Separation in CaO-SiO2-CaCl2 Chlorine-Containing Silicate Glasses.

Science.gov (United States)

Swansbury, Laura A; Mountjoy, Gavin; Chen, Xiaojing; Karpukhina, Natalia; Hill, Robert

2017-06-08

The addition of chlorine into a bioactive glass composition is expected to reduce its abrasiveness and increase its bioactivity, which is important for dental applications such as toothpastes. There is a lack of information and understanding regarding the structural role of chlorine in chlorine-containing bioactive silicate glasses. This has prompted classical core-shell model molecular dynamics simulations of (50 - x/2)CaO-(50 - x/2)SiO 2 -xCaCl 2 glasses to be performed, where x ranges from x = 0.0 to 43.1 mol % CaCl 2 . These ternary glasses are advantageous for a fundamental study because they do not have additional network formers (e.g., phosphorus pentoxide) or modifiers (e.g., sodium) typically found in bioactive glass compositions. The (50 - x/2)CaO-(50 - x/2)SiO 2 -xCaCl 2 glasses were seen to become phase-separated around the x = 16.1 mol % CaCl 2 composition, and chlorine predominantly coordinated with calcium. These findings provide a solid foundation for further computational modeling work on more complex chlorine-containing bioactive glass compositions.

Benefits and drawbacks of zinc in glass ionomer bone cements

Energy Technology Data Exchange (ETDEWEB)

Brauer, Delia S; Hill, Robert G [Unit of Dental Physical Sciences, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Gentleman, Eileen; Stevens, Molly M [Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Farrar, David F, E-mail: d.brauer@qmul.ac.uk [Smith and Nephew Research Centre, York Science Park, Heslington YO10 5DF (United Kingdom)

2011-08-15

Glass polyalkenoate (ionomer) cements (GPCs) based on poly(acrylic acid) and fluoro-alumino-silicate glasses are successfully used in a variety of orthopaedic and dental applications; however, they release small amounts of aluminium, which is a neurotoxin and inhibits bone mineralization in vivo. Therefore there has been significant interest in developing aluminium-free glasses containing zinc for forming GPCs because zinc can play a similar structural role in the glass, allowing for glass degradation and subsequent cement setting, and is reported to have beneficial effects on bone formation. We created zinc-containing GPCs and characterized their mechanical properties and biocompatibility. Zinc-containing cements showed adhesion to bone close to 1 MPa, which was significantly greater than that of zinc-free cements (<0.05 MPa) and other currently approved biological adhesives. However, zinc-containing cements produced significantly lower metabolic activity in mouse osteoblasts exposed to cell culture medium conditioned with the cements than controls. Results show that although low levels of zinc may be beneficial to cells, zinc concentrations of 400 {mu}M Zn{sup 2+} or more resulted in cell death. In summary, we demonstrate that while zinc-containing GPCs possess excellent mechanical properties, they fail basic biocompatibility tests, produce an acute cytotoxic response in vitro, which may preclude their use in vivo.

Borosilicate nuclear waste glass alteration kinetics theoretical basis for the kinetic law of nuclear glass alteration

International Nuclear Information System (INIS)

Jegou, Ch.; Gin, St.; Advocat, Th.; Vernaz, E.

1997-01-01

Work carried out since the early 1980's to predict the long-term behavior of nuclear containment glasses has revealed the inadequacy of existing models, notably in accounting for the fundamental mechanisms involved in some complex systems (e.g. glass-water-clay), inciting us to examine and discuss the theoretical basis for the hypotheses generally assumed in our models. This paper discusses the theoretical basis for the Aagaard-Helgeson law and its application to nuclear glasses. The contribution of other types of kinetic laws is also considered to describe the alteration kinetics of nuclear glasses. (authors)

Galantamine improves olfactory learning in the Ts65Dn mouse model of Down syndrome.

Science.gov (United States)

de Souza, Fabio M Simoes; Busquet, Nicolas; Blatner, Megan; Maclean, Kenneth N; Restrepo, Diego

2011-01-01

Down syndrome (DS) is the most common form of congenital intellectual disability. Although DS involves multiple disturbances in various tissues, there is little doubt that in terms of quality of life cognitive impairment is the most serious facet and there is no effective treatment for this aspect of the syndrome. The Ts65Dn mouse model of DS recapitulates multiple aspects of DS including cognitive impairment. Here the Ts65Dn mouse model of DS was evaluated in an associative learning paradigm based on olfactory cues. In contrast to disomic controls, trisomic mice exhibited significant deficits in olfactory learning. Treatment of trisomic mice with the acetylcholinesterase inhibitor galantamine resulted in a significant improvement in olfactory learning. Collectively, our study indicates that olfactory learning can be a sensitive tool for evaluating deficits in associative learning in mouse models of DS and that galantamine has therapeutic potential for improving cognitive abilities.

Do Female Researchers Face a Glass Ceiling in France? A Hazard Model of Promotions

OpenAIRE

Sabatier, Mareva

2010-01-01

Abstract The present article examines whether French female researchers face a glass ceiling, an invisible barrier to promotion. Using an original database from the National Institute for Agricultural Research, we estimate duration models for promotions. The methodology used allowed us to take into account censored observations and unobserved heterogeneity. Our results show a significant gender effect that does not contradict the glass-ceiling hypothesis. In addition, factors that ...

Application of the GRAAL model to leaching experiments with SON68 nuclear glass in initially pure water

International Nuclear Information System (INIS)

Frugier, P.; Chave, T.; Gin, S.; Lartigue, J.-E.

2009-01-01

Based on a review of the current state of knowledge concerning the aqueous alteration of SON68 nuclear glass we have proposed a mechanistic model, GRAAL (Glass Reactivity with Allowance for the Alteration Layer) [P. Frugier, S. Gin, Y. Minet, T. Chave, B. Bonin, N. Godon, J.E. Lartigue, P. Jollivet, A. Ayral, L. De Windt, G. Santarini, J. Nucl. Mater. 380 (2008) 8]. This article describes how the GRAAL model hypotheses are solved using a calculation code coupling chemistry and transport. The geochemical solution of this model combines three major phenomena: chemical equilibria in solution, water and ion transport by convection or diffusion, and element diffusion through the passivating reactive interphase. The model results are compared with experimental data for SON68 glass leached in initially pure water both in a closed system and in renewed media. The comparison shows the model very satisfactorily accounts for variations in the pH and the element concentrations in solution as a function of time, the glass surface area in contact with solution, and the solution renewal rate. This success is due to the fact that the diffusion of elements through the alteration gel is taken into account in the model. This mechanism cannot be disregarded under most experimental conditions - if only to predict the solution pH - and must therefore be an integral part of the geochemical model.

Glass science tutorial: Lecture number-sign 1, Chemistry and properties of oxide glasses. Professor William C. LaCourse, Lecturer

International Nuclear Information System (INIS)

Kruger, A.A.

1994-10-01

The tutorial covers the following topics: Definitions and terminology; Introduction to glass structure and properties; The glass transition; Structure/property relationships in oxide glasses; Generalized models for predicting structure/properties; Glass surfaces; Chemical durability; and Mechanical properties

A Mathematical Model of Skeletal Muscle Disease and Immune Response in the mdx Mouse

Directory of Open Access Journals (Sweden)

Abdul Salam Jarrah

2014-01-01

Full Text Available Duchenne muscular dystrophy (DMD is a genetic disease that results in the death of affected boys by early adulthood. The genetic defect responsible for DMD has been known for over 25 years, yet at present there is neither cure nor effective treatment for DMD. During early disease onset, the mdx mouse has been validated as an animal model for DMD and use of this model has led to valuable but incomplete insights into the disease process. For example, immune cells are thought to be responsible for a significant portion of muscle cell death in the mdx mouse; however, the role and time course of the immune response in the dystrophic process have not been well described. In this paper we constructed a simple mathematical model to investigate the role of the immune response in muscle degeneration and subsequent regeneration in the mdx mouse model of Duchenne muscular dystrophy. Our model suggests that the immune response contributes substantially to the muscle degeneration and regeneration processes. Furthermore, the analysis of the model predicts that the immune system response oscillates throughout the life of the mice, and the damaged fibers are never completely cleared.

Effect of CPAP in a Mouse Model of Hyperoxic Neonatal Lung Injury

Science.gov (United States)

Reyburn, Brent; Fiore, Juliann M. Di; Raffay, Thomas; Martin, Richard J.; Y.S., Prakash; Jafri, Anjum; MacFarlane, Peter M.

2015-01-01

Background Continuous positive airway pressure [CPAP] and supplemental oxygen have become the mainstay of neonatal respiratory support in preterm infants. Although oxygen therapy is associated with respiratory morbidities including bronchopulmonary dysplasia [BPD], the long-term effects of CPAP on lung function are largely unknown. We used a hyperoxia-induced mouse model of BPD to explore the effects of daily CPAP during the first week of life on later respiratory system mechanics. Objective To test the hypothesis that daily CPAP in a newborn mouse model of BPD improves longer term respiratory mechanics. Methods Mouse pups from C57BL/6 pregnant dams were exposed to room air [RA] or hyperoxia [50% O2, 24hrs/day] for the first postnatal week with or without exposure to daily CPAP [6cmH2O, 3hrs/day]. Respiratory system resistance [Rrs] and compliance [Crs] were measured following a subsequent 2 week period of room RA recovery. Additional measurements included radial alveolar counts and macrophage counts. Results Mice exposed to hyperoxia had significantly elevated Rrs, decreased Crs, reduced alveolarization, and increased macrophage counts at three weeks compared to RA treated mice. Daily CPAP treatment significantly improved Rrs, Crs and alveolarization, and decreased lung macrophage infiltration in hyperoxia-exposed pups. Conclusions We have demonstrated that daily CPAP had a longer term benefit on baseline respiratory system mechanics in a neonatal mouse model of BPD. We speculate that this beneficial effect of CPAP was the consequence of a decrease in the inflammatory response and resultant alveolar injury associated with hyperoxic newborn lung injury. PMID:26394387

Lessons learned using different mouse models during space radiation-induced lung tumorigenesis experiments

Science.gov (United States)

Wang, Jian; Zhang, Xiangming; Wang, Ping; Wang, Xiang; Farris, Alton B.; Wang, Ya

2016-06-01

Unlike terrestrial ionizing radiation, space radiation, especially galactic cosmic rays (GCR), contains high energy charged (HZE) particles with high linear energy transfer (LET). Due to a lack of epidemiologic data for high-LET radiation exposure, it is highly uncertain how high the carcinogenesis risk is for astronauts following exposure to space radiation during space missions. Therefore, using mouse models is necessary to evaluate the risk of space radiation-induced tumorigenesis; however, which mouse model is better for these studies remains uncertain. Since lung tumorigenesis is the leading cause of cancer death among both men and women, and low-LET radiation exposure increases human lung carcinogenesis, evaluating space radiation-induced lung tumorigenesis is critical to enable safe Mars missions. Here, by comparing lung tumorigenesis obtained from different mouse strains, as well as miR-21 in lung tissue/tumors and serum, we believe that wild type mice with a low spontaneous tumorigenesis background are ideal for evaluating the risk of space radiation-induced lung tumorigenesis, and circulating miR-21 from such mice model might be used as a biomarker for predicting the risk.

Recycle Glass in Foam Glass Production

DEFF Research Database (Denmark)

Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

The foam glass industry turn recycle glass into heat insulating building materials. The foaming process is relative insensitive to impurities in the recycle glass. It is therefore considered to play an important role in future glass recycling. We show and discuss trends of use of recycled glasses...... in foam glass industry and the supply sources and capacity of recycle glass....

Environment overwhelms both nature and nurture in a model spin glass

Science.gov (United States)

Middleton, A. Alan; Yang, Jie

We are interested in exploring what information determines the particular history of the glassy long term dynamics in a disordered material. We study the effect of initial configurations and the realization of stochastic dynamics on the long time evolution of configurations in a two-dimensional Ising spin glass model. The evolution of nearest neighbor correlations is computed using patchwork dynamics, a coarse-grained numerical heuristic for temporal evolution. The dependence of the nearest neighbor spin correlations at long time on both initial spin configurations and noise histories are studied through cross-correlations of long-time configurations and the spin correlations are found to be independent of both. We investigate how effectively rigid bond clusters coarsen. Scaling laws are used to study the convergence of configurations and the distribution of sizes of nearly rigid clusters. The implications of the computational results on simulations and phenomenological models of spin glasses are discussed. We acknowledge NSF support under DMR-1410937 (CMMT program).

On modeling of statistical properties of classical 3D spin glasses

International Nuclear Information System (INIS)

Gevorkyan, A.S.; Abajyan, H.G.; Ayryan, E.A.

2011-01-01

We study statistical properties of 3D classical spin glass layer of certain width and infinite length. The 3D spin glass is represented as an ensemble of disordered 1D spatial spin chains (SSC) where interactions are random between spin chains (nonideal ensemble of 1D SSCs). It is proved that in the limit of Birkhoff's ergodic hypothesis performance, 3D spin glasses can be generated by Hamiltonian of disordered 1D SSC with random environment. Disordered 1D SSC is defined on a regular lattice where one randomly oriented spin is put on each node of lattice. Also, it is supposed that each spin randomly interacts with six nearest-neighboring spins (two spins on lattice and four in the environment). The recurrent transcendental equations are obtained on the nodes of spin-chain lattice. These equations, combined with the Silvester conditions, allow step-by-step construction of spin chain in the ground state of energy where all spins are in the minimal energy of a classical Hamiltonian. On the basis of these equations an original high-performance parallel algorithm is developed for 3D spin glasses simulation. Distributions of different parameters of unperturbed spin glass are calculated. In particular, it is analytically proved and numerical calculations show that the distribution of spin-spin interaction constant in Heisenberg nearest-neighboring Hamiltonian model, as opposed to widely used Gauss-Edwards-Anderson distribution, satisfies the Levy alpha-stable distribution law which does not have variance. A new formula is proposed for construction of partition function in the form of a one-dimensional integral on the energy distribution of 1D SSCs

Current Understanding and Remaining Challenges in Modeling Long-Term Degradation of Borosilicate Nuclear Waste Glasses

International Nuclear Information System (INIS)

Vienna, John D.; Ryan, Joseph V.; Gin, Stephane; Inagaki, Yaohiro

2013-01-01

Chemical durability is not a single material property that can be uniquely measured. Instead it is the response to a host of coupled material and environmental processes whose rates are estimated by a combination of theory, experiment, and modeling. High-level nuclear waste (HLW) glass is perhaps the most studied of any material yet there remain significant technical gaps regarding their chemical durability. The phenomena affecting the long-term performance of HLW glasses in their disposal environment include surface reactions, transport properties to and from the reacting glass surface, and ion exchange between the solid glass and the surrounding solution and alteration products. The rates of these processes are strongly influenced and are coupled through the solution chemistry, which is in turn influenced by the reacting glass and also by reaction with the near-field materials and precipitation of alteration products. Therefore, those processes must be understood sufficiently well to estimate or bound the performance of HLW glass in its disposal environment over geologic time-scales. This article summarizes the current state of understanding of surface reactions, transport properties, and ion exchange along with the near-field materials and alteration products influences on solution chemistry and glass reaction rates. Also summarized are the remaining technical gaps along with recommended approaches to fill those technical gaps

Stability and replica symmetry in the ising spin glass: a toy model

International Nuclear Information System (INIS)

De Dominicis, C.; Mottishaw, P.

1986-01-01

Searching for possible replica symmetric solutions in an Ising spin glass (in the tree approximation) we investigate a toy model whose bond distribution has two non vanishing cumulants (instead of one only as in a gaussian distribution)

Automatic Assessment of Craniofacial Growth in a Mouse Model of Crouzon Syndrome

DEFF Research Database (Denmark)

Thorup, Signe Strann; Larsen, Rasmus; Darvann, Tron Andre

2009-01-01

for each mouse-type; growth models were created using linear interpolation and visualized as 3D animations. Spatial regions of significantly different growth were identified using the local False Discovery Rate method, estimating the expected percentage of false predictions in a set of predictions. For all......-rigid volumetric image registration was applied to micro-CT scans of ten 4-week and twenty 6-week euthanized mice for growth modeling. Each age group consisted of 50% normal and 50% Crouzon mice. Four 3D mean shapes, one for each mouse-type and age group were created. Extracting a dense field of growth vectors...... a tool for spatially detailed automatic phenotyping. MAIN OBJECTIVES OF PRESENTATION: We will present a 3D growth model of normal and Crouzon mice, and differences will be statistically and visually compared....

Molecular Alterations in a Mouse Cardiac Model of Friedreich Ataxia

DEFF Research Database (Denmark)

Anzovino, Amy; Chiang, Shannon; Brown, Bronwyn E

2017-01-01

mechanisms. Using a mouse conditional frataxin knockout (KO) model in the heart and skeletal muscle, we examined the Nrf2 pathway in these tissues. Frataxin KO results in fatal cardiomyopathy, whereas skeletal muscle was asymptomatic. In the KO heart, protein oxidation and a decreased glutathione...

Inhibitory Effect of Waste Glass Powder on ASR Expansion Induced by Waste Glass Aggregate

Directory of Open Access Journals (Sweden)

Shuhua Liu

2015-10-01

Full Text Available Detailed research is carried out to ascertain the inhibitory effect of waste glass powder (WGP on alkali-silica reaction (ASR expansion induced by waste glass aggregate in this paper. The alkali reactivity of waste glass aggregate is examined by two methods in accordance with the China Test Code SL352-2006. The potential of WGP to control the ASR expansion is determined in terms of mean diameter, specific surface area, content of WGP and curing temperature. Two mathematical models are developed to estimate the inhibitory efficiency of WGP. These studies show that there is ASR risk with an ASR expansion rate over 0.2% when the sand contains more than 30% glass aggregate. However, WGP can effectively control the ASR expansion and inhibit the expansion rate induced by the glass aggregate to be under 0.1%. The two mathematical models have good simulation results, which can be used to evaluate the inhibitory effect of WGP on ASR risk.

Glass leaching performance

International Nuclear Information System (INIS)

Chick, L.A.; Turcotte, R.P.

1983-05-01

Current understanding of the leaching performance of high-level nuclear waste (HLW) glass is summarized. The empirical model of waste glass leaching behavior developed shows that at high water flow rates the glass leach rate is kinetically limited to a maximum value. At intermediate water flow rates, leaching is limited by the solution concentration of silica and decreases with decreasing water flow rates. Release of soluble elements is controlled by silica dissolution because silica forms the binding network of the glass. At low water flow rates, mass loss rates reach values controlled by formation rates of alteration minerals, or by diffusion of dissolution products through essentially stagnant water. The parameters reviewed with respect to their quantifiable influence on leaching behavior include temperature, pH, leachant composition, glass composition, thermal history, and radiation. Of these, temperature is most important since the rate of mass loss approximately doubles with each 10 0 C increase in dilute solutions. The pH has small effects within the 4 to 10 range. The chemical composition of the leachant is most important with regard to its influence on alteration product formation. Glass composition exhibits the largest effects at high flow rates where improved glasses leach from ten to thirty times slower than glass 76 to 68. The effects of the thermal history (devitrification) of the glass are not likely to be significant. Radiation effects are important primarily in that radiolysis can potentially drive pH values to less than 4. Radiation damage to the glass causes insignificant changes in leaching performance

Heating-induced glass-glass and glass-liquid transformations in computer simulations of water

Science.gov (United States)

Chiu, Janet; Starr, Francis W.; Giovambattista, Nicolas

2014-03-01

Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T "phase diagram" for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related

Heating-induced glass-glass and glass-liquid transformations in computer simulations of water

International Nuclear Information System (INIS)

Chiu, Janet; Giovambattista, Nicolas; Starr, Francis W.

2014-01-01

Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T “phase diagram” for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related

Heating-induced glass-glass and glass-liquid transformations in computer simulations of water

Energy Technology Data Exchange (ETDEWEB)

Chiu, Janet; Giovambattista, Nicolas [Department of Physics, Brooklyn College of the City University of New York, Brooklyn, New York 11210 (United States); Starr, Francis W. [Department of Physics, Wesleyan University, Middletown, Connecticut 06459 (United States)

2014-03-21

Water exists in at least two families of glassy states, broadly categorized as the low-density (LDA) and high-density amorphous ice (HDA). Remarkably, LDA and HDA can be reversibly interconverted via appropriate thermodynamic paths, such as isothermal compression and isobaric heating, exhibiting first-order-like phase transitions. We perform out-of-equilibrium molecular dynamics simulations of glassy water using the ST2 model to study the evolution of LDA and HDA upon isobaric heating. Depending on pressure, glass-to-glass, glass-to-crystal, glass-to-vapor, as well as glass-to-liquid transformations are found. Specifically, heating LDA results in the following transformations, with increasing heating pressures: (i) LDA-to-vapor (sublimation), (ii) LDA-to-liquid (glass transition), (iii) LDA-to-HDA-to-liquid, (iv) LDA-to-HDA-to-liquid-to-crystal, and (v) LDA-to-HDA-to-crystal. Similarly, heating HDA results in the following transformations, with decreasing heating pressures: (a) HDA-to-crystal, (b) HDA-to-liquid-to-crystal, (c) HDA-to-liquid (glass transition), (d) HDA-to-LDA-to-liquid, and (e) HDA-to-LDA-to-vapor. A more complex sequence may be possible using lower heating rates. For each of these transformations, we determine the corresponding transformation temperature as function of pressure, and provide a P-T “phase diagram” for glassy water based on isobaric heating. Our results for isobaric heating dovetail with the LDA-HDA transformations reported for ST2 glassy water based on isothermal compression/decompression processes [Chiu et al., J. Chem. Phys. 139, 184504 (2013)]. The resulting phase diagram is consistent with the liquid-liquid phase transition hypothesis. At the same time, the glass phase diagram is sensitive to sample preparation, such as heating or compression rates. Interestingly, at least for the rates explored, our results suggest that the LDA-to-liquid (HDA-to-liquid) and LDA-to-HDA (HDA-to-LDA) transformation lines on heating are related

Hypothalamic food intake regulation in a cancer-cachectic mouse model

OpenAIRE

Dwarkasing, Jvalini T.; van Dijk, Miriam; Dijk, Francina J.; Boekschoten, Mark V.; Faber, Joyce; Argilès, Josep M.; Laviano, Alessandro; Müller, Michael; Witkamp, Renger F.; van Norren, Klaske

2013-01-01

Background Appetite is frequently affected in cancer patients leading to anorexia and consequently insufficient food intake. In this study, we report on hypothalamic gene expression profile of a cancer-cachectic mouse model with increased food intake. In this model, mice bearing C26 tumour have an increased food intake subsequently to the loss of body weight. We hypothesise that in this model, appetite-regulating systems in the hypothalamus, which apparently fail in anorexia, are still able t...

Calculation of glass forming ranges in Al-Ni-RE (Ce, La, Y) ternary alloys and their sub-binaries based on Miedema's model

International Nuclear Information System (INIS)

Sun, S.P.; Yi, D.Q.; Liu, H.Q.; Zang, B.; Jiang, Y.

2010-01-01

Research highlights: → A method based on semi-empirical Miedema's and Toop's model for predicting glass forming range of ternary alloy system has been systematically described. → The method is superior to conventional models by considering the effect of the thermodynamic asymmetric component when dealing with a ternary alloy system. → The glass forming ranges of Al-Ni-RE (Al-Ni-Ce, Al-Ni-Y and Al-Ni-La) systems and their sub-binaries have been successfully calculated. → The present calculations using the method are in well agreement with experiments. → This model is especially useful for predicting the glass forming range of ternary alloy system because the calculations do not require experimental data. - Abstract: A method based on the semi-empirical Miedema's and Toop's model for calculating the glass forming range of a ternary alloy system was systematically described. The method is superior to conventional models by considering the effect of the thermodynamic asymmetric component when dealing with a ternary alloy system. Using this method, the glass forming ranges of Al-Ni-RE (Ce, La, Y) systems and their sub-binaries were successfully predicted. The mixing enthalpy and mismatch entropy were calculated, and their effects on the glass forming abilities of Al-Ni-RE (Ce, La, Y) systems were also discussed. The glass forming abilities of Al-Ni-Ce, Al-Ni-La and Al-Ni-Y are found to be close. The calculated glass forming ranges agree with experiments well. Meanwhile, the enthalpy change from amorphous phase to solid solution in the glass forming ranges was calculated, and the results suggest that those alloys close to the Ni-RE sub-binary system have higher glass forming abilities.

Recent technological advances in using mouse models to study ovarian cancer.

Science.gov (United States)

House, Carrie Danielle; Hernandez, Lidia; Annunziata, Christina Messineo

2014-01-01

Serous epithelial ovarian cancer (SEOC) is the most lethal gynecological cancer in the United States with disease recurrence being the major cause of morbidity and mortality. Despite recent advances in our understanding of the molecular mechanisms responsible for the development of SEOC, the survival rate for women with this disease has remained relatively unchanged in the last two decades. Preclinical mouse models of ovarian cancer, including xenograft, syngeneic, and genetically engineered mice, have been developed to provide a mechanism for studying the development and progression of SEOC. Such models strive to increase our understanding of the etiology and dissemination of ovarian cancer in order to overcome barriers to early detection and resistance to standard chemotherapy. Although there is not a single model that is most suitable for studying ovarian cancer, improvements have led to current models that more closely mimic human disease in their genotype and phenotype. Other advances in the field, such as live animal imaging techniques, allow effective monitoring of the microenvironment and therapeutic efficacy. New and improved preclinical mouse models, combined with technological advances to study such models, will undoubtedly render success of future human clinical trials for patients with SEOC.

Two-state model of light induced activation and thermal bleaching of photochromic glasses: theory and experiments

International Nuclear Information System (INIS)

Ferrari, Jose A.; Perciante, Cesar D.

2008-01-01

The behavior of photochromic glasses during activation and bleaching is investigated. A two-state phenomenological model describing light-induced activation (darkening) and thermal bleaching is presented. The proposed model is based on first-order kinetics. We demonstrate that the time behavior in the activation process (acting simultaneously with the thermal fading) can be characterized by two relaxation times that depend on the intensity of the activating light. These characteristic times are lower than the decay times of the pure thermal bleaching process. We study the temporal evolution of the glass optical density and its dependence on the activating intensity. We also present a series of activation and bleaching experiments that validate the proposed model. Our approach may be used to gain more insight into the transmittance behavior of photosensitive glasses, which could be potentially relevant in a broad range of applications, e.g., real-time holography and reconfigurable optical memories

A recombinant lentiviral PDGF-driven mouse model of proneural glioblastoma.

Science.gov (United States)

Rahme, Gilbert J; Luikart, Bryan W; Cheng, Chao; Israel, Mark A

2018-02-19

Mouse models of glioblastoma (GBM), the most aggressive primary brain tumor, are critical for understanding GBM pathology and can contribute to the preclinical evaluation of therapeutic agents. Platelet-derived growth factor (PDGF) signaling has been implicated in the development and pathogenesis of GBM, specifically the proneural subtype. Although multiple mouse models of PDGF-driven glioma have been described, they require transgenic mice engineered to activate PDGF signaling and/or impair tumor suppressor genes and typically represent lower-grade glioma. We designed recombinant lentiviruses expressing both PDGFB and a short hairpin RNA targeting Cdkn2a to induce gliomagenesis following stereotactic injection into the dentate gyrus of adult immunocompetent mice. We engineered these viruses to coexpress CreERT2 with PDGFB, allowing for deletion of floxed genes specifically in transduced cells, and designed another version of this recombinant lentivirus in which enhanced green fluorescent protein was coexpressed with PDGFB and CreERT2 to visualize transduced cells. The dentate gyrus of injected mice showed hypercellularity one week post-injection and subsequently developed bona fide tumors with the pathologic hallmarks of GBM leading to a median survival of 77 days post-injection. Transcriptomic analysis of these tumors revealed a proneural gene expression signature. Informed by the genetic alterations observed in human GBM, we engineered a novel mouse model of proneural GBM. While reflecting many of the advantages of transgenic mice, this model allows for the facile in vivo testing of gene function in tumor cells and makes possible the rapid production of large numbers of immunocompetent tumor-bearing mice for preclinical testing of therapeutics. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Isotope effect in glass-transition temperature and ionic conductivity of lithium-borate glasses

International Nuclear Information System (INIS)

Nagasaki, Takanori; Morishima, Ryuta; Matsui, Tsuneo

2002-01-01

The glass-transition temperature and the electrical conductivity of lithium borate (0.33Li 2 O-0.67B 2 O 3 ) glasses with various isotopic compositions were determined by differential thermal analysis and by impedance spectroscopy, respectively. The obtained glass-transition temperature as well as the vibrational frequency of B-O network structure was independent of lithium isotopic composition. This result indicates that lithium ions, which exist as network modifier, only weakly interact with B-O network structure. In addition, the glass-transition temperature increased with 10 B content although the reason has not been understood. The electrical conductivity, on the other hand, increased with 6 Li content. The ratio of the conductivity of 6 Li glass to that of 7 Li glass was found to be 2, being larger than the value (7/6) 1/2 calculated with the simple classical diffusion theory. This strong mass dependence could be explained by the dynamic structure model, which assumes local structural relaxation even far below the glass-transition temperature. Besides, the conductivity appeared to increase with the glass-transition temperature. Possible correlations between the glass-transition temperature and the electrical conductivity were discussed. (author)

Arrhythmia phenotype in mouse models of human long QT.

Science.gov (United States)

Salama, Guy; Baker, Linda; Wolk, Robert; Barhanin, Jacques; London, Barry

2009-03-01

Enhanced dispersion of repolarization (DR) was proposed as a unifying mechanism, central to arrhythmia genesis in the long QT (LQT) syndrome. In mammalian hearts, K(+) channels are heterogeneously expressed across the ventricles resulting in 'intrinsic' DR that may worsen in long QT. DR was shown to be central to the arrhythmia phenotype of transgenic mice with LQT caused by loss of function of the dominant mouse K(+) currents. Here, we investigated the arrhythmia phenotype of mice with targeted deletions of KCNE1 and KCNH2 genes which encode for minK/IsK and Merg1 (mouse homolog of human ERG) proteins resulting in loss of function of I(Ks) and I(Kr), respectively. Both currents are important human K(+) currents associated with LQT5 and LQT2. Loss of minK, a protein subunit that interacts with KvLQT1, results in a marked reduction of I(Ks) giving rise to the Jervell and Lange-Nielsen syndrome and the reduced KCNH2 gene reduces MERG and I(Kr). Hearts were perfused, stained with di-4-ANEPPS and optically mapped to compare action potential durations (APDs) and arrhythmia phenotype in homozygous minK (minK(-/-)) and heterozygous Merg1 (Merg(+/-)) deletions and littermate control mice. MinK(-/-) mice has similar APDs and no arrhythmias (n = 4). Merg(+/-) mice had prolonged APDs (from 20 +/- 6 to 32 +/- 9 ms at the base, p mice (60% vs. 10%). A comparison of mouse models of LQT based on K(+) channel mutations important to human and mouse repolarization emphasizes DR as a major determinant of arrhythmia vulnerability.

Study of the mechanisms underlying resumptions of alteration. Modeling and evaluation of the impact on nuclear waste glasses

International Nuclear Information System (INIS)

Fournier, Maxime

2015-01-01

A sudden and still poorly understood phenomenon, the resumption of alteration results in a sudden acceleration of the glass alteration rate due to the destabilization of the amorphous passivating layer formed on the glass surface. Understanding the origin and the consequences of this phenomenon is a major issue for the prediction of nuclear glass long-term behavior. This study quantitatively links the alteration degree of a six-oxide reference glass and the formation mechanisms of zeolites and C-S-H that control the solution chemistry. The role played by the decrease in aluminum concentration as an indicator of resumption is highlighted. It appears that the resumption occurrence and rate are correlated to the couple (T, pH), but even in the most adverse situations the resumption rate is lower than the initial alteration rate, which remains the fastest kinetic regime. Previously limited to alkaline pH, the characterization of alteration resumptions was extended to conditions more representative of those found in a geological repository. This approach required the development of a new tool: seeding, that reduces or eliminates the latency period preceding a resumption. The results obtained demonstrate its usefulness in understanding the role of zeolites in amorphous layer destabilization and for modeling alteration resumptions. A geochemical modeling approach to alteration resumption is proposed, based on the formalism of the GRAAL glass alteration model. It is based on the calculation of zeolite thermodynamic constants, on the implementation of their nucleation and growth kinetics, and on assumptions related to the solubility of the amorphous layer. When zeolite precipitation consumes alkali, glass alteration - driven by zeolite precipitation - releases alkali. The model highlights the importance of such chemical couplings and shows that, in the stoichiometry of French nuclear reference glass, their cumulative effects are the cause of a pH decrease which limits

Enhanced Reconstitution of Human Erythropoiesis and Thrombopoiesis in an Immunodeficient Mouse Model with KitWv Mutations

Directory of Open Access Journals (Sweden)

Ayano Yurino

2016-09-01

Full Text Available In human-to-mouse xenograft models, reconstitution of human hematopoiesis is usually B-lymphoid dominant. Here we show that the introduction of homozygous KitWv mutations into C57BL/6.Rag2nullIl2rgnull mice with NOD-Sirpa (BRGS strongly promoted human multi-lineage reconstitution. After xenotransplantation of human CD34+CD38− cord blood cells, these newly generated C57BL/6.Rag2nullIl2rgnullNOD-Sirpa KitWv/Wv (BRGSKWv/Wv mice showed significantly higher levels of human cell chimerism and long-term multi-lineage reconstitution compared with BRGS mice. Strikingly, this mouse displayed a robust reconstitution of human erythropoiesis and thrombopoiesis with terminal maturation in the bone marrow. Furthermore, depletion of host macrophages by clodronate administration resulted in the presence of human erythrocytes and platelets in the circulation. Thus, attenuation of mouse KIT signaling greatly enhances the multi-lineage differentiation of human hematopoietic stem and progenitor cells (HSPCs in mouse bone marrow, presumably by outcompeting mouse HSPCs to occupy suitable microenvironments. The BRGSKWv/Wv mouse model is a useful tool to study human multi-lineage hematopoiesis.

Parisi function for two spin glass models

International Nuclear Information System (INIS)

Sibani, P.; Hertz, J.A.

1984-01-01

The probability distribution function P(q) for the overlap of pairs of metastable states and the associated Parisi order function q(x) are calculated exactly at zero temperature for two simple models. The first is a chain in which each spin interacts randomly with the sum of all the spins between it and one end of the chain; the second is an infinite-range limit of a spin glass version of Dyson's hierarchical model. Both have nontrivial overlap distributions: In the first case the problem reduces to a variable-step-length random walk problem, leading to q(x)=sin(πx). In the second model P(q) can be calculated by a simple recursion relation which generates devil's staircase structure in q(x). If the fraction p of antiferromagnetic bonds is less than 1/√2, the staircase is complete and the fractal dimensionality of the complement of the domain where q(x) is flat is log 2/log (1/p 2 ). In both models the space of metastable states can be described in terms of Cayley trees, which however have a different physical interpretation than in the S.K. model. (orig.)

A mouse model of mammary hyperplasia induced by oral hormone ...

African Journals Online (AJOL)

Methods and Materials: To address the mechanism, we developed a mouse model of mammary hyperplasia. We gave mice estradiol valerate tablets and progesterone capsules sequentially for one month by intragastric administration. Results: Mice treated by this method had a series of pathological changes which are ...

Animal models for studying neural crest development: is the mouse different?

Science.gov (United States)

Barriga, Elias H; Trainor, Paul A; Bronner, Marianne; Mayor, Roberto

2015-05-01

The neural crest is a uniquely vertebrate cell type and has been well studied in a number of model systems. Zebrafish, Xenopus and chick embryos largely show consistent requirements for specific genes in early steps of neural crest development. By contrast, knockouts of homologous genes in the mouse often do not exhibit comparable early neural crest phenotypes. In this Spotlight article, we discuss these species-specific differences, suggest possible explanations for the divergent phenotypes in mouse and urge the community to consider these issues and the need for further research in complementary systems. © 2015. Published by The Company of Biologists Ltd.

First-order model for durability of Hanford waste glasses as a function of composition

International Nuclear Information System (INIS)

Hrma, P.; Piepel, G.F.; Schweiger, M.J.; Smith, D.E.

1992-04-01

Two standard chemical durability tests, the static leach test MCC-1 and product consistency test PCT, were conducted on simulated borosilicate glasses that encompass the expected range of compositions to be produced in the Hanford Waste Vitrification Plant (HWVP). A first-order empirical model was fitted to the data from each test method. The results indicate that glass durability is increased by addition of Al 2 O 3 , moderately increased by addition of ZrO 2 and SiO 2 , and decreased by addition of Li 2 O, Na 2 O, B 2 O 3 , and MgO. Addition of Fe 2 O 3 and CaO produce an indifferent or reducing effect on durability according to the test method. This behavior and a statistically significant lack of fit are attributed to the effects of multiple chemical reactions occurring during glass-water interaction. Liquid-liquid immiscibility is suspected to be responsible for extremely low durability of some glasses

Preparation and characterization of physically modified glass beads used as model carriers in dry powder inhalers.

Science.gov (United States)

Zellnitz, Sarah; Redlinger-Pohn, Jakob Dominik; Kappl, Michael; Schroettner, Hartmuth; Urbanetz, Nora Anne

2013-04-15

The aim of this work is the physical modification and characterization of the surface topography of glass beads used as model carriers in dry powder inhalers (DPIs). By surface modification the contact area between drug and carrier and thereby interparticle forces may be modified. Thus the performance of DPIs that relies on interparticle interactions may be improved. Glass beads were chosen as model carriers because various prospects of physical surface modification may be applied without affecting other factors also impacting interparticle interactions like particle size and shape. To generate rough surfaces glass beads were processed mechanically by friction and impaction in a ball mill with different grinding materials that were smaller and harder with respect to the glass beads. By varying the grinding time (4 h, 8 h) and by using different grinding media (tungsten carbide, quartz) surfaces with different shades of roughness were generated. Depending on the hardness of the grinding material and the grinding time the surface roughness was more or less pronounced. Surface roughness parameters and specific surface area were determined via several complementary techniques in order to get an enhanced understanding of the impact of the modifying procedure on the surface properties of the glass beads. Copyright © 2013 Elsevier B.V. All rights reserved.

Configurational entropy of polar glass formers and the effect of electric field on glass transition

Energy Technology Data Exchange (ETDEWEB)

Matyushov, Dmitry V., E-mail: dmitrym@asu.edu [Department of Physics and School of Molecular Sciences, Arizona State University, P.O. Box 871504, Tempe, Arizona 85287 (United States)

2016-07-21

A model of low-temperature polar liquids is constructed that accounts for the configurational heat capacity, entropy, and the effect of a strong electric field on the glass transition. The model is based on the Padé-truncated perturbation expansions of the liquid state theory. Depending on parameters, it accommodates an ideal glass transition of vanishing configurational entropy and its avoidance, with a square-root divergent enumeration function at the point of its termination. A composite density-temperature parameter ρ{sup γ}/T, often used to represent combined pressure and temperature data, follows from the model. The theory is in good agreement with the experimental data for excess (over the crystal state) thermodynamics of molecular glass formers. We suggest that the Kauzmann entropy crisis might be a signature of vanishing configurational entropy of a subset of degrees of freedom, multipolar rotations in our model. This scenario has observable consequences: (i) a dynamical crossover of the relaxation time and (ii) the fragility index defined by the ratio of the excess heat capacity and excess entropy at the glass transition. The Kauzmann temperature of vanishing configurational entropy and the corresponding glass transition temperature shift upward when the electric field is applied. The temperature shift scales quadratically with the field strength.

Configurational entropy of polar glass formers and the effect of electric field on glass transition.

Science.gov (United States)

Matyushov, Dmitry V

2016-07-21

A model of low-temperature polar liquids is constructed that accounts for the configurational heat capacity, entropy, and the effect of a strong electric field on the glass transition. The model is based on the Padé-truncated perturbation expansions of the liquid state theory. Depending on parameters, it accommodates an ideal glass transition of vanishing configurational entropy and its avoidance, with a square-root divergent enumeration function at the point of its termination. A composite density-temperature parameter ρ(γ)/T, often used to represent combined pressure and temperature data, follows from the model. The theory is in good agreement with the experimental data for excess (over the crystal state) thermodynamics of molecular glass formers. We suggest that the Kauzmann entropy crisis might be a signature of vanishing configurational entropy of a subset of degrees of freedom, multipolar rotations in our model. This scenario has observable consequences: (i) a dynamical crossover of the relaxation time and (ii) the fragility index defined by the ratio of the excess heat capacity and excess entropy at the glass transition. The Kauzmann temperature of vanishing configurational entropy and the corresponding glass transition temperature shift upward when the electric field is applied. The temperature shift scales quadratically with the field strength.

Systematic assessment of microneedle injection into the mouse cornea

Directory of Open Access Journals (Sweden)

Matthaei Mario

2012-06-01

Full Text Available Abstract Background Corneal intrastromal injection is an important mode of gene-vector application to subepithelial layers. In a mouse model, this procedure is substantially complicated by the reduced corneal dimensions. Furthermore, it may be difficult to estimate the corneal area reached by the volume of a single injection. This study aimed to investigate intrastromal injections into the mouse cornea using different microneedles and to quantify the effect of injecting varying volumes. A reproducible injection technique is described. Methods Forty eyes of 20 129 Sv/J mice were tested. India ink was intrastromally injected using 30° beveled 33 G needles, tri-surface 25° beveled 35 G needles, or hand-pulled and 25° beveled glass needles. Each eye received a single injection of a volume of 1 or 2 μL. Corneoscleral buttons were fixed and flat mounted for computer-assisted quantification of the affected corneal area. Histological assessment was performed to investigate the intrastromal location of the injected dye. Results A mean corneal area of 5.0 ±1.4 mm2 (mean ± SD and 7.7 ±1.4 mm2 was covered by intrastromal injections of 1 and 2 μL, respectively. The mean percentage of total corneal area reached ranged from 39% to 53% for 1 μL injections, and from 65% to 81% for 2 μL injections. Injections using the 33 G needles tended to provide the highest distribution area. Perforation rates were 8% for 30° beveled 33 G needles and 44% for tri-surface beveled 35 G needles. No perforation was observed with glass needle; however, intrastromal breakage of needle tips was noted in 25% of these cases. Conclusions Intracorneal injection using a 30° beveled 33 G needle was safe and effective. The use of tri-surface beveled 35 G needles substantially increased the number of corneal perforations. Glass needles may break inside the corneal stroma. Injections of 1 μL and 2 μL resulted in an overall mean of 49% and 73% respectively

Double-bond defect modelling in As-S glasses

International Nuclear Information System (INIS)

Boyko, V; Shpotyuk, O; Hyla, M

2010-01-01

Ab initio calculations with the RHF/6-311G* basis set are used for geometrical optimization of regular pyramidal and defect quasi-tetrahedral clusters in binary As-S glasses. It is shown that quasi-tetrahedral S=AsS 3/2 structural units are impossible as main network-building blocks in these glasses.

Double-bond defect modelling in As-S glasses

Energy Technology Data Exchange (ETDEWEB)

Boyko, V; Shpotyuk, O; Hyla, M, E-mail: shpotyuk@novas.lviv.ua

2010-11-15

Ab initio calculations with the RHF/6-311G* basis set are used for geometrical optimization of regular pyramidal and defect quasi-tetrahedral clusters in binary As-S glasses. It is shown that quasi-tetrahedral S=AsS{sub 3/2} structural units are impossible as main network-building blocks in these glasses.

Bioenergetic Defects and Oxidative Damage in Transgenic Mouse Models of Neurodegenerative Disorders

National Research Council Canada - National Science Library

Brown, Susan

1999-01-01

... (HE) and familial amyotrophic lateral sclerosis (FALS), using transgenic mouse models. Studies in this first year employed C-14-2-deoxyglucose in vivo autoradiography and spectrophotometric metabolic enzyme assays...

Perspectives on spin glasses

CERN Document Server

Contucci, Pierluigi

2013-01-01

Presenting and developing the theory of spin glasses as a prototype for complex systems, this book is a rigorous and up-to-date introduction to their properties. The book combines a mathematical description with a physical insight of spin glass models. Topics covered include the physical origins of those models and their treatment with replica theory; mathematical properties like correlation inequalities and their use in the thermodynamic limit theory; main exact solutions of the mean field models and their probabilistic structures; and the theory of the structural properties of the spin glass phase such as stochastic stability and the overlap identities. Finally, a detailed account is given of the recent numerical simulation results and properties, including overlap equivalence, ultrametricity and decay of correlations. The book is ideal for mathematical physicists and probabilists working in disordered systems.

High-fertility phenotypes: two outbred mouse models exhibit substantially different molecular and physiological strategies warranting improved fertility.

Science.gov (United States)

Langhammer, Martina; Michaelis, Marten; Hoeflich, Andreas; Sobczak, Alexander; Schoen, Jennifer; Weitzel, Joachim M

2014-01-01

Animal models are valuable tools in fertility research. Worldwide, there are more than 400 transgenic or knockout mouse models available showing a reproductive phenotype; almost all of them exhibit an infertile or at least subfertile phenotype. By contrast, animal models revealing an improved fertility phenotype are barely described. This article summarizes data on two outbred mouse models exhibiting a 'high-fertility' phenotype. These mouse lines were generated via selection over a time period of more than 40 years and 161 generations. During this selection period, the number of offspring per litter and the total birth weight of the entire litter nearly doubled. Concomitantly with the increased fertility phenotype, several endocrine parameters (e.g. serum testosterone concentrations in male animals), physiological parameters (e.g. body weight, accelerated puberty, and life expectancy), and behavioral parameters (e.g. behavior in an open field and endurance fitness on a treadmill) were altered. We demonstrate that the two independently bred high-fertility mouse lines warranted their improved fertility phenotype using different molecular and physiological strategies. The fertility lines display female- as well as male-specific characteristics. These genetically heterogeneous mouse models provide new insights into molecular and cellular mechanisms that enhance fertility. In view of decreasing fertility in men, these models will therefore be a precious information source for human reproductive medicine. Translated abstract A German translation of abstract is freely available at http://www.reproduction-online.org/content/147/4/427/suppl/DC1.

Diffusion processes in nuclear waste glasses

International Nuclear Information System (INIS)

Serruys, Y.; Limoge, Y.; Brebec, G.

1992-01-01

Problems concerning the containment of nuclear wastes are presented. Different materials which have been considered for this purpose are briefly reviewed and we see why glass is one of the favorite candidates. It is focussed on what is known about diffusion in 'simple enough' glasses. After a recall concerning the structure and possible defects, the main results on diffusion in 'simple' glasses are given and it is shown what these results involve for the mechanisms of diffusion. The diffusion models are presented which can account for transport in random media: percolation and random walk models. Specific phenomena for the nuclear waste glasses are considered: the effect of irradiation on diffusion and leaching (i.e. corrosion by water). Finally diffusion data in nuclear waste glasses are presented. (author). 199 refs., 6 figs., 1 tab

The common parasite Toxoplasma gondii induces prostatic inflammation and microglandular hyperplasia in a mouse model.

Science.gov (United States)

Colinot, Darrelle L; Garbuz, Tamila; Bosland, Maarten C; Wang, Liang; Rice, Susan E; Sullivan, William J; Arrizabalaga, Gustavo; Jerde, Travis J

2017-07-01

Inflammation is the most prevalent and widespread histological finding in the human prostate, and associates with the development and progression of benign prostatic hyperplasia and prostate cancer. Several factors have been hypothesized to cause inflammation, yet the role each may play in the etiology of prostatic inflammation remains unclear. This study examined the possibility that the common protozoan parasite Toxoplasma gondii induces prostatic inflammation and reactive hyperplasia in a mouse model. Male mice were infected systemically with T. gondii parasites and prostatic inflammation was scored based on severity and focality of infiltrating leukocytes and epithelial hyperplasia. We characterized inflammatory cells with flow cytometry and the resulting epithelial proliferation with bromodeoxyuridine (BrdU) incorporation. We found that T. gondii infects the mouse prostate within the first 14 days of infection and can establish parasite cysts that persist for at least 60 days. T. gondii infection induces a substantial and chronic inflammatory reaction in the mouse prostate characterized by monocytic and lymphocytic inflammatory infiltrate. T. gondii-induced inflammation results in reactive hyperplasia, involving basal and luminal epithelial proliferation, and the exhibition of proliferative inflammatory microglandular hyperplasia in inflamed mouse prostates. This study identifies the common parasite T. gondii as a new trigger of prostatic inflammation, which we used to develop a novel mouse model of prostatic inflammation. This is the first report that T. gondii chronically encysts and induces chronic inflammation within the prostate of any species. Furthermore, T. gondii-induced prostatic inflammation persists and progresses without genetic manipulation in mice, offering a powerful new mouse model for the study of chronic prostatic inflammation and microglandular hyperplasia. © 2017 Wiley Periodicals, Inc.

Modeling of the fringe shift in multiple beam interference for glass ...

Indian Academy of Sciences (India)

A quadratic model is suggested to describe the fringe shift occurred due to the phase variations of uncladded glass fiber introduced between the two plates of the liquid wedge interferometer. The fringe shift of the phase object is represented in the harmonic term which appears in the denominator of the Airy distribution ...

Superconductive analogue of spin glasses

International Nuclear Information System (INIS)

Feigel'man, M.; Ioffe, L.; Vinokur, V.; Larkin, A.

1987-07-01

The properties of granular superconductors in magnetic fields, namely the existence of a new superconductive state analogue of the low-temperature superconductive state in spin glasses are discussed in the frame of the infinite-range model and the finite-range models. Experiments for elucidation of spin-glass superconductive state in real systems are suggested. 30 refs

Effects of environmental enrichment on the amyotrophic lateral sclerosis mouse model.

Science.gov (United States)

Sorrells, A D; Corcoran-Gomez, K; Eckert, K A; Fahey, A G; Hoots, B L; Charleston, L B; Charleston, J S; Roberts, C R; Markowitz, H

2009-04-01

The manner in which an animal's environment is furnished may have significant implications for animal welfare as well as research outcomes. We evaluated four different housing conditions to determine the effects of what has been considered standard rodent enrichment and the exercise opportunities those environments allow on disease progression in the amyotrophic lateral sclerosis mouse model. Forty-eight copper/zinc superoxide dismutase mice (strain: B6SJL-TgN [SOD1-G931]1Gur) (SOD1) and 48 control (C) (strain: B6SJL-TgN[SOD1]2Gur) male mice were randomly assigned to four different conditions where 12 SOD1 and 12 C animals were allotted to each condition (n = 96). Conditions tested the effects of standard housing, a forced exercise regime, access to a mouse house and opportunity for ad libitum exercise on a running wheel. In addition to the daily all-occurrence behavioural sampling, mice were weighed and tested twice per week on gait and Rotor-Rod performance until the mice reached the age of 150 days (C) or met the criteria for our humane endpoint (SOD1). The SOD1 mice exposed to the forced exercise regime and wheel access did better in average lifespan and Rotor-Rod performance, than SOD1 mice exposed to the standard cage and mouse house conditions. In SOD1 mice, stride length remained longest throughout the progression of the disease in mice exposed to the forced exercise regime compared with other SOD1 conditions. Within the control group, mice in the standard cage and forced exercise regime conditions performed significantly less than the mice with the mouse house and wheels on the Rotor-Rod. Alpha motor neuron counts were highest in mice with wheels and in mice exposed to forced exercise regime in both mouse strains. All SOD1 mice had significantly lower alpha neuron counts than controls (P model, and may have implications for the effects of these strategies on experimental outcomes.

From Immunodeficiency to Humanization: The Contribution of Mouse Models to Explore HTLV-1 Leukemogenesis

Directory of Open Access Journals (Sweden)

Eléonore Pérès

2015-12-01

Full Text Available The first discovered human retrovirus, Human T-Lymphotropic Virus type 1 (HTLV-1, is responsible for an aggressive form of T cell leukemia/lymphoma. Mouse models recapitulating the leukemogenesis process have been helpful for understanding the mechanisms underlying the pathogenesis of this retroviral-induced disease. This review will focus on the recent advances in the generation of immunodeficient and human hemato-lymphoid system mice with a particular emphasis on the development of mouse models for HTLV-1-mediated pathogenesis, their present limitations and the challenges yet to be addressed.

Ultrasonic vocalizations: a tool for behavioural phenotyping of mouse models of neurodevelopmental disorders

OpenAIRE

Scattoni, Maria Luisa; Crawley, Jacqueline; Ricceri, Laura

2008-01-01

In neonatal mice ultrasonic vocalizations have been studied both as an early communicative behavior of the pup-mother dyad and as a sign of an aversive affective state. Adult mice of both sexes produce complex ultrasonic vocalization patterns in different experimental/social contexts. All these vocalizations are becoming an increasingly valuable assay for behavioral phenotyping throughout the mouse life-span and alterations of the ultrasound patterns have been reported in several mouse models...

Lessons learned using different mouse models during space radiation-induced lung tumorigenesis experiments.

Science.gov (United States)

Wang, Jian; Zhang, Xiangming; Wang, Ping; Wang, Xiang; Farris, Alton B; Wang, Ya

2016-06-01

Unlike terrestrial ionizing radiation, space radiation, especially galactic cosmic rays (GCR), contains high energy charged (HZE) particles with high linear energy transfer (LET). Due to a lack of epidemiologic data for high-LET radiation exposure, it is highly uncertain how high the carcinogenesis risk is for astronauts following exposure to space radiation during space missions. Therefore, using mouse models is necessary to evaluate the risk of space radiation-induced tumorigenesis; however, which mouse model is better for these studies remains uncertain. Since lung tumorigenesis is the leading cause of cancer death among both men and women, and low-LET radiation exposure increases human lung carcinogenesis, evaluating space radiation-induced lung tumorigenesis is critical to enable safe Mars missions. Here, by comparing lung tumorigenesis obtained from different mouse strains, as well as miR-21 in lung tissue/tumors and serum, we believe that wild type mice with a low spontaneous tumorigenesis background are ideal for evaluating the risk of space radiation-induced lung tumorigenesis, and circulating miR-21 from such mice model might be used as a biomarker for predicting the risk. Copyright © 2016 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

Rasagiline ameliorates olfactory deficits in an alpha-synuclein mouse model of Parkinson's disease.

Directory of Open Access Journals (Sweden)

Géraldine H Petit

Full Text Available Impaired olfaction is an early pre-motor symptom of Parkinson's disease. The neuropathology underlying olfactory dysfunction in Parkinson's disease is unknown, however α-synuclein accumulation/aggregation and altered neurogenesis might play a role. We characterized olfactory deficits in a transgenic mouse model of Parkinson's disease expressing human wild-type α-synuclein under the control of the mouse α-synuclein promoter. Preliminary clinical observations suggest that rasagiline, a monoamine oxidase-B inhibitor, improves olfaction in Parkinson's disease. We therefore examined whether rasagiline ameliorates olfactory deficits in this Parkinson's disease model and investigated the role of olfactory bulb neurogenesis. α-Synuclein mice were progressively impaired in their ability to detect odors, to discriminate between odors, and exhibited alterations in short-term olfactory memory. Rasagiline treatment rescued odor detection and odor discrimination abilities. However, rasagiline did not affect short-term olfactory memory. Finally, olfactory changes were not coupled to alterations in olfactory bulb neurogenesis. We conclude that rasagiline reverses select olfactory deficits in a transgenic mouse model of Parkinson's disease. The findings correlate with preliminary clinical observations suggesting that rasagiline ameliorates olfactory deficits in Parkinson's disease.

Thermokinetic model of borosilicate glass dissolution: contextual affinity

International Nuclear Information System (INIS)

Advocat, T.; Vernaz, E.; Crovisier, J.L.; Fritz, B.

1989-01-01

Short and long-term geochemical interactions of R7T7 nuclear glass with water at 100 0 C were simulated with the DISSOL thermokinetic computer code. Both the dissolved glass quantity and the resulting water composition, saturation states and mineral quantities produced were calculated as a function of time. The rate equation used in the simulation was first proposed by Aagaard and Helgeson. It simulates a gradually diminishing dissolution rate as the reaction affinity diminishes. The best agreement with 1-year experimental data was obtained with a reaction affinity calculated from silica activity (Grambow's hypothesis) rather than taking into account the activity of all the glass components as proposed by Jantzen and Plodinec. The concept of residual affinity was introduced by Grambow to express the fact that the glass dissolution rate does not cease. We prefer to replace the term residual affinity by contextual affinity, which expresses the influence on the dissolution rate of three factors: the solution chemistry, the metastability of SiO 2 (m), and the possible precipitation of certain aluminosilicates such as zeolites. 19 refs

Multiscale probabilistic modeling of a crack bridge in glass fiber reinforced concrete

Directory of Open Access Journals (Sweden)

Rypla R.

2017-06-01

Full Text Available The present paper introduces a probabilistic approach to simulating the crack bridging effects of chopped glass strands in cement-based matrices and compares it to a discrete rigid body spring network model with semi-discrete representation of the chopped strands. The glass strands exhibit random features at various scales, which are taken into account by both models. Fiber strength and interface stress are considered as random variables at the scale of a single fiber bundle while the orientation and position of individual bundles with respect to a crack plane are considered as random variables at the crack bridge scale. At the scale of the whole composite domain, the distribution of fibers and the resulting number of crack-bridging fibers is considered. All the above random effects contribute to the variability of the crack bridge performance and result in size-dependent behavior of a multiply cracked composite.

Genetic mouse models of brain ageing and Alzheimer's disease.

Science.gov (United States)

Bilkei-Gorzo, Andras

2014-05-01

Progression of brain ageing is influenced by a complex interaction of genetic and environmental factors. Analysis of genetically modified animals with uniform genetic backgrounds in a standardised, controlled environment enables the dissection of critical determinants of brain ageing on a molecular level. Human and animal studies suggest that increased load of damaged macromolecules, efficacy of DNA maintenance, mitochondrial activity, and cellular stress defences are critical determinants of brain ageing. Surprisingly, mouse lines with genetic impairment of anti-oxidative capacity generally did not show enhanced cognitive ageing but rather an increased sensitivity to oxidative challenge. Mouse lines with impaired mitochondrial activity had critically short life spans or severe and rapidly progressing neurodegeneration. Strains with impaired clearance in damaged macromolecules or defects in the regulation of cellular stress defences showed alterations in the onset and progression of cognitive decline. Importantly, reduced insulin/insulin-like growth factor signalling generally increased life span but impaired cognitive functions revealing a complex interaction between ageing of the brain and of the body. Brain ageing is accompanied by an increased risk of developing Alzheimer's disease. Transgenic mouse models expressing high levels of mutant human amyloid precursor protein showed a number of symptoms and pathophysiological processes typical for early phase of Alzheimer's disease. Generally, therapeutic strategies effective against Alzheimer's disease in humans were also active in the Tg2576, APP23, APP/PS1 and 5xFAD lines, but a large number of false positive findings were also reported. The 3xtg AD model likely has the highest face and construct validity but further studies are needed. Copyright © 2013 Elsevier Inc. All rights reserved.

Glass consistency and glass performance

International Nuclear Information System (INIS)

Plodinec, M.J.; Ramsey, W.G.

1994-01-01

Glass produced by the Defense Waste Processing Facility (DWPF) will have to consistently be more durable than a benchmark glass (evaluated using a short-term leach test), with high confidence. The DWPF has developed a Glass Product Control Program to comply with this specification. However, it is not clear what relevance product consistency has on long-term glass performance. In this report, the authors show that DWPF glass, produced in compliance with this specification, can be expected to effectively limit the release of soluble radionuclides to natural environments. However, the release of insoluble radionuclides to the environment will be limited by their solubility, and not glass durability

Memory Effects in the Two-Level Model for Glasses

Science.gov (United States)

Aquino, Gerardo; Allahverdyan, Armen; Nieuwenhuizen, Theo M.

2008-07-01

We study an ensemble of two-level systems interacting with a thermal bath. This is a well-known model for glasses. The origin of memory effects in this model is a quasistationary but nonequilibrium state of a single two-level system, which is realized due to a finite-rate cooling and slow thermally activated relaxation. We show that single-particle memory effects, such as negativity of the specific heat under reheating, vanish for a sufficiently disordered ensemble. In contrast, a disordered ensemble displays a collective memory effect [similar to the Kovacs effect], where nonequilibrium features of the ensemble are monitored via a macroscopic observable. An experimental realization of the effect can be used to further assess the consistency of the model.

Inhibiting Effects of Achyranthes Bidentata Polysaccharide and Lycium Barbarum Polysaccharide on Nonenzyme Glycation in D-galactose Induced Mouse Aging Model

Institute of Scientific and Technical Information of China (English)

HONG-BIN DENG; DA-PENG CUI; JIAN-MING JIANG; YAN-CHUN FENG; NIAN-SHENG CAI; DIAN-DONG LI

2003-01-01

To investigate the inhibiting effects and mechanism of achyranthes bidentata polysaccharide (ABP) and lycium barbarum polysaccharide (LBP) on nonenzyme glycation in D-galactose induced mouse aging model. Methods Serum AGE levels were determined by AGE-ELISA, MTT method was used to determine lymphocyte proliferation, IL-2 activity was determined by a bioassay method. Spontaneous motor activity was used to detect mouse's neuromuscular movement, latency of step-through method was used to examine learning and memory abilities of mouse, colormetric assay was used to determine hydroxyproline concentration in mouse skin, pyrogallol autoxidation method was used to determine superoxide dismutase (SOD) activity of erythrocytes. Results Decreased levels of serum AGE, hydroxyproline concentration in mouse skin and spontaneous motor activity in D-galactose mouse aging model were detected after treated with ABP or LBP, while lymphocyte proliferation and IL-2 activity, learning and memory abilities,SOD activity of erythrocytes, were enhanced. Conclusions ABP and LBP could inhibit nonenzyme glycation in D-galactose induced mouse aging model in vivo and ABP has a better inhibiting effect than LBP.

Spin glasses and algorithm benchmarks: A one-dimensional view

International Nuclear Information System (INIS)

Katzgraber, H G

2008-01-01

Spin glasses are paradigmatic models that deliver concepts relevant for a variety of systems. However, rigorous analytical results are difficult to obtain for spin-glass models, in particular for realistic short-range models. Therefore large-scale numerical simulations are the tool of choice. Concepts and algorithms derived from the study of spin glasses have been applied to diverse fields in computer science and physics. In this work a one-dimensional long-range spin-glass model with power-law interactions is discussed. The model has the advantage over conventional systems in that by tuning the power-law exponent of the interactions the effective space dimension can be changed thus effectively allowing the study of large high-dimensional spin-glass systems to address questions as diverse as the existence of an Almeida-Thouless line, ultrametricity and chaos in short range spin glasses. Furthermore, because the range of interactions can be changed, the model is a formidable test-bed for optimization algorithms

CORRELATION OF THE GLASS TRANSITION TEMPERATURE OF PLASTICIZED PVC USING A LATTICE FLUID MODEL

Science.gov (United States)

A model has been developed to describe the composition dependence of the glass transition temperature (Tg) of polyvinyl chloride (PVC) + plasticizer mixtures. The model is based on Sanchez-Lacombe equation of state and the Gibbs-Di Marzio criterion, which states that th...

PALS investigations of matrix Vycor glass doped with molecules of luminescent dye and silver nanoparticles. Discrepancies from the ETE model

Directory of Open Access Journals (Sweden)

Gorgol Marek

2015-12-01

Full Text Available A thermal stability of three materials: undoped reference Vycor glass, glass filled with ROT-305 red dye, and silver nanoparticles was investigated by positron annihilation lifetime spectroscopy (PALS in a broad temperature range (from 93 to 473 K. The attempt of pore size calculations from the ortho-positronium lifetime data was performed using the extended Tao-Eldrup (ETE model. Below room temperature, a significant decrease in lifetime values of the longest-lived component was found for all the samples. This effect could not be explained by thermal shrinkage of the material and is probably caused by interaction of o-Ps with a Vycor glass matrix. The greatest discrepancy from the ETE model predictions was observed for the reference glass. Doping the base material with dye molecules and silver nanoparticles resulted in similar small decrease in this discrepancy. After reheating the samples to the room temperature, the PALS components returned to the initial values. In the temperature range of 293–473 K, quite good agreement between PALS results and the ETE model predictions was observed for the reference glass and the glass incorporated with dye molecules. The observed small discrepancy in this range could possibly be partly explained by thermal expansion of the material. For the glass doped with silver nanoparticles, a significant change in PALS parameters was observed in the temperature range from 403 to 473 K.

Mouse neuroblastoma cell-based model and the effect of epileptic events on calcium oscillations and neural spikes

Science.gov (United States)

Kim, Suhwan; Jung, Unsang; Baek, Juyoung; Lee, Sangwon; Jung, Woonggyu; Kim, Jeehyun; Kang, Shinwon

2013-01-01

Recently, mouse neuroblastoma cells have been considered as an attractive model for the study of human neurological and prion diseases, and they have been intensively used as a model system in different areas. For example, the differentiation of neuro2a (N2A) cells, receptor-mediated ion current, and glutamate-induced physiological responses have been actively investigated with these cells. These mouse neuroblastoma N2A cells are of interest because they grow faster than other cells of neural origin and have a number of other advantages. The calcium oscillations and neural spikes of mouse neuroblastoma N2A cells in epileptic conditions are evaluated. Based on our observations of neural spikes in these cells with our proposed imaging modality, we reported that they can be an important model in epileptic activity studies. We concluded that mouse neuroblastoma N2A cells produce epileptic spikes in vitro in the same way as those produced by neurons or astrocytes. This evidence suggests that increased levels of neurotransmitter release due to the enhancement of free calcium from 4-aminopyridine causes the mouse neuroblastoma N2A cells to produce epileptic spikes and calcium oscillations.

DISC1 mouse models as a tool to decipher gene-environment interactions in psychiatric disorders

Directory of Open Access Journals (Sweden)

Tyler eCash-Padgett

2013-09-01

Full Text Available DISC1 was discovered in a Scottish pedigree in which a chromosomal translocation that breaks this gene segregates with psychiatric disorders, mainly depression and schizophrenia. Linkage and association studies in diverse populations support DISC1 as a susceptibility gene to a variety of neuropsychiatric disorders. Many Disc1 mouse models have been generated to study its neuronal functions. These mouse models display variable phenotypes, some of them relevant to schizophrenia, others to depression.The Disc1 mouse models are popular genetic models for studying gene-environment interactions in schizophrenia. Five different Disc1 models have been combined with environmental factors. The environmental stressors employed can be classified as either early immune activation or later social paradigms. These studies cover major time points along the neurodevelopmental trajectory: prenatal, early postnatal, adolescence, and adulthood. Various combinations of molecular, anatomical and behavioral methods have been used to assess the outcomes. Additionally, three of the studies sought to rescue the resulting abnormalities.Here we provide background on the environmental paradigms used, summarize the results of these studies combining Disc1 mouse models with environmental stressors and discuss what we can learn and how to proceed. A major question is how the genetic and environmental factors determine which psychiatric disorder will be clinically manifested. To address this we can take advantage of the many Disc1 models available and expose them to the same environmental stressor. The complementary experiment would be to expose the same model to different environmental stressors. DISC1 is an ideal gene for this approach, since in the Scottish pedigree the same chromosomal translocation results in different psychiatric conditions.

Polymorphic crystallization of metal-metalloid-glasses above the glass transition temperature

International Nuclear Information System (INIS)

Koster, U.; Schunemann, U.; Stephenson, G.B.; Brauer, S.; Sutton, M.

1992-01-01

Crystallization of metal-metalloid glasses is known to proceed by nucleation and growth processes. Using crystallization statistics in partially crystallized glasses, at temperatures below the glass transition temperature, time-dependent heterogeneous nucleation has been found to occur at a number of quenched-in nucleation sites. Close to the glass transition temperature crystallization proceeds so rapidly that partially crystallized microstructures could not be obtained. Initial results form fully crystallized glasses exhibit evidence for a transient homogeneous nucleation process at higher temperatures. These conclusions are derived post mortem. At there may be some change of the microstructure after crystallization is finished or during he subsequent quenching, it is desirable to directly obtain information during the early stages of crystallization. Recently reported work by Sutton et al. showed that structural changes can be observed in situ during crystallization by time-resolved x-ray diffraction on time scales as short as milliseconds. The aim o the paper is to present the authors study of the crystallization behavior at temperatures near the glass transition by in-situ x-ray diffraction studies and by microstructural analysis after rapid heating experiments. The results are compared to those derived from a computer model of the crystallization process

Effect of induced peritoneal endometriosis on oocyte and embryo quality in a mouse model.

Science.gov (United States)

Cohen, J; Ziyyat, A; Naoura, I; Chabbert-Buffet, N; Aractingi, S; Darai, E; Lefevre, B

2015-02-01

To assess the impact of peritoneal endometriosis on oocyte and embryo quality in a mouse model. Peritoneal endometriosis was surgically induced in 33 B6CBA/F1 female mice (endometriosis group, N = 17) and sham-operated were used as control (sham group, N = 16). Mice were superovulated 4 weeks after surgery and mated or not, to collect E0.5-embryos or MII-oocytes. Evaluation of oocyte and zygote quality was done by immunofluorescence under spinning disk confocal microscopy. Endometriosis-like lesions were observed in all mice of endometriosis group. In both groups, a similar mean number of MII oocytes per mouse was observed in non-mated mice (30.2 vs 32.6), with a lower proportion of normal oocytes in the endometriosis group (61 vs 83 %, p endometriosis group (21 vs 35.5, p = 0.02) without difference in embryo quality. Our results support that induced peritoneal endometriosis in a mouse model is associated with a decrease in oocyte quality and embryo number. This experimental model allows further studies to understand mechanisms of endometriosis-associated infertility.

Structure, biodegradation behavior and cytotoxicity of alkali-containing alkaline-earth phosphosilicate glasses

Energy Technology Data Exchange (ETDEWEB)

Kansal, Ishu; Reddy, AlluAmarnath [Department of Materials and Ceramics Engineering, University of Aveiro, CICECO, 3810-193 Aveiro (Portugal); Muñoz, Francisco [Ceramics and Glass Institute (CSIC), Kelsen 5, 28049 Madrid (Spain); Choi, Seong-Jun [Department of Nanobiomedical Science and BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330714 (Korea, Republic of); Kim, Hae-Won [Department of Nanobiomedical Science and BK21 PLUS NBM Global Research Center for Regenerative Medicine, Dankook University, Cheonan 330714 (Korea, Republic of); Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330714 (Korea, Republic of); Department of Biomaterials Science, College of Dentistry, Dankook University, Cheonan 330714 (Korea, Republic of); Tulyaganov, Dilshat U. [Turin Polytechnic University in Tashkent, 100095 Tashkent (Uzbekistan); Ferreira, José M.F., E-mail: jmf@ua.pt [Department of Materials and Ceramics Engineering, University of Aveiro, CICECO, 3810-193 Aveiro (Portugal)

2014-11-01

We report on the effect of sodium on the structure, chemical degradation and bioactivity of glasses in the CaO–MgO–SiO{sub 2}–P{sub 2}O{sub 5}–CaF{sub 2} system. The {sup 29}Si and {sup 31}P magic angle spinning-nuclear magnetic resonance spectroscopy of melt-quenched glasses with varying Na{sub 2}O/MgO ratios exhibit a silicate glass network with the dominance of Q{sup 2}(Si) units and phosphorus mainly forming orthophosphate species. Sodium incorporation in the glasses did not induce a significant structural change in the silicate network, while it did influence the phosphate environment due to its lower ionic field strength in comparison with that of magnesium. The apatite forming ability of glasses has been investigated by immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1 h and 7 days while their chemical degradation has been studied in Tris–HCl in accordance with ISO-10993-14. Increasing Na{sup +}/Mg{sup 2+} ratio caused a decrease in the chemical durability of glasses and in the apatite forming ability especially during initial steps of interaction between glass and SBF solution. The cellular responses were observed in vitro on bulk glass samples using mouse-derived pre-osteoblastic MC3T3-E1 cell line. The preliminary study suggested that the increasing alkali-concentration in glasses led to cytotoxicity in the cell culture medium. - Highlights: • Na{sup +} did not induce significant structural changes in chemical Si environment. • Sodium is more prone to affect the chemical environment around P. • Increasing Na{sup +}/Mg{sup 2+} ratios hinder bio-mineralization and chemical durability. • Alkali-containing glasses confer cyto-toxicity to the cell culture medium.

Structure, biodegradation behavior and cytotoxicity of alkali-containing alkaline-earth phosphosilicate glasses

International Nuclear Information System (INIS)

Kansal, Ishu; Reddy, AlluAmarnath; Muñoz, Francisco; Choi, Seong-Jun; Kim, Hae-Won; Tulyaganov, Dilshat U.; Ferreira, José M.F.

2014-01-01

We report on the effect of sodium on the structure, chemical degradation and bioactivity of glasses in the CaO–MgO–SiO 2 –P 2 O 5 –CaF 2 system. The 29 Si and 31 P magic angle spinning-nuclear magnetic resonance spectroscopy of melt-quenched glasses with varying Na 2 O/MgO ratios exhibit a silicate glass network with the dominance of Q 2 (Si) units and phosphorus mainly forming orthophosphate species. Sodium incorporation in the glasses did not induce a significant structural change in the silicate network, while it did influence the phosphate environment due to its lower ionic field strength in comparison with that of magnesium. The apatite forming ability of glasses has been investigated by immersion of glass powders in simulated body fluid (SBF) for time durations varying between 1 h and 7 days while their chemical degradation has been studied in Tris–HCl in accordance with ISO-10993-14. Increasing Na + /Mg 2+ ratio caused a decrease in the chemical durability of glasses and in the apatite forming ability especially during initial steps of interaction between glass and SBF solution. The cellular responses were observed in vitro on bulk glass samples using mouse-derived pre-osteoblastic MC3T3-E1 cell line. The preliminary study suggested that the increasing alkali-concentration in glasses led to cytotoxicity in the cell culture medium. - Highlights: • Na + did not induce significant structural changes in chemical Si environment. • Sodium is more prone to affect the chemical environment around P. • Increasing Na + /Mg 2+ ratios hinder bio-mineralization and chemical durability. • Alkali-containing glasses confer cyto-toxicity to the cell culture medium

Effects of gypenosides on anxiety disorders in MPTP-lesioned mouse model of Parkinson's disease.

Science.gov (United States)

Shin, Keon Sung; Zhao, Ting Ting; Choi, Hyun Sook; Hwang, Bang Yeon; Lee, Chong Kil; Lee, Myung Koo

2014-06-03

Ethanol extract (GP-EX) of Gynostemma pentaphyllum (GP) ameliorates chronic stress-induced anxiety in mice. The present study investigated the effects of gypenoside-enriched components (GPS), GP-EX and water extract of GP (GP-WX) on MPTP lesion-induced affective disorders in C57BL/6 mice. GPS (50mg/kg) and GP-EX (50mg/kg) for 21 day-treatment period improved the symptom of anxiety disorders in the MPTP-lesioned mouse model of PD with or without L-DOPA treatment, which was examined by the elevated plus-maze and marble burying tests. In these states, treatments with GPS (50mg/kg) and GP-EX (50mg/kg) significantly increased the brain levels of dopamine and serotonin in the MPTP-lesioned mouse model of PD with or without l-DOPA treatment. In addition, treatments with GPS (50mg/kg) and GP-EX (50mg/kg) showed protective effects on dopaminergic neurons in MPTP-lesioned mouse model of PD with or without L-DOPA treatment. In contrast, GPS (30 mg/kg) and GP-WX (50mg/kg) showed anxiolytic effects in the same animal models, but it was not significant. These results suggest that GPS (50mg/kg) and GP-EX (50mg/kg) showed anxiolytic effects on affective disorders and protective effects on dopaminergic neurons by modulating the brain levels of dopamine and serotonin in the MPTP-lesioned mouse model of PD with or without l-DOPA treatment. Clinical trials of GPS and GP-EX need to be conducted further so as to develop adjuvant therapeutic agents for PD patients. Copyright © 2014 Elsevier B.V. All rights reserved.

Food withdrawal lowers energy expenditure and induces inactivity in long-chain fatty acid oxidation-deficient mouse models.

Science.gov (United States)

Diekman, Eugene F; van Weeghel, Michel; Wanders, Ronald J A; Visser, Gepke; Houten, Sander M

2014-07-01

Very long-chain acyl-CoA dehydrogenase (VLCAD) deficiency is an inherited disorder of mitochondrial long-chain fatty acid β-oxidation (FAO). Patients with VLCAD deficiency may present with hypoglycemia, hepatomegaly, cardiomyopathy, and myopathy. Although several mouse models have been developed to aid in the study of the pathogenesis of long-chain FAO defects, the muscular phenotype is underexposed. To address the muscular phenotype, we used a newly developed mouse model on a mixed genetic background with a more severe defect in FAO (LCAD(-/-); VLCAD(+/-)) in addition to a validated mouse model (LCAD(-/-); VLCAD(+/+)) and compared them with wild-type (WT) mice. We found that both mouse models show a 20% reduction in energy expenditure (EE) and a 3-fold decrease in locomotor activity in the unfed state. In addition, we found a 1.7°C drop in body temperature in unfed LCAD(-/-); VLCAD(+/+) mice compared with WT body temperature. We conclude that food withdrawal-induced inactivity, hypothermia, and reduction in EE are novel phenotypes associated with FAO deficiency in mice. Unexpectedly, inactivity was not explained by rhabdomyolysis, but rather reflected the overall reduced capacity of these mice to generate heat. We suggest that mice are partly protected against the negative consequence of an FAO defect.-Diekman, E. F., van Weeghel, M., Wanders, R. J. A., Visser, G., Houten, S. M. Food withdrawal lowers energy expenditure and induces inactivity in long-chain fatty acid oxidation-deficient mouse models. © FASEB.

Computational Fluid Dynamics Modeling of Bubbling in a Viscous Fluid for Validation of Waste Glass Melter Modeling

Energy Technology Data Exchange (ETDEWEB)

Abboud, Alexander William [Idaho National Laboratory; Guillen, Donna Post [Idaho National Laboratory

2016-01-01

At the Hanford site, radioactive waste stored in underground tanks is slated for vitrification for final disposal. A comprehensive knowledge of the glass batch melting process will be useful in optimizing the process, which could potentially reduce the cost and duration of this multi-billion dollar cleanup effort. We are developing a high-fidelity heat transfer model of a Joule-heated ceramic lined melter to improve the understanding of the complex, inter-related processes occurring with the melter. The glass conversion rates in the cold cap layer are dependent on promoting efficient heat transfer. In practice, heat transfer is augmented by inserting air bubblers into the molten glass. However, the computational simulations must be validated to provide confidence in the solutions. As part of a larger validation procedure, it is beneficial to split the physics of the melter into smaller systems to validate individually. The substitution of molten glass for a simulant liquid with similar density and viscosity at room temperature provides a way to study mixing through bubbling as an isolated effect without considering the heat transfer dynamics. The simulation results are compared to experimental data obtained by the Vitreous State Laboratory at the Catholic University of America using bubblers placed within a large acrylic tank that is similar in scale to a pilot glass waste melter. Comparisons are made for surface area of the rising air bubbles between experiments and CFD simulations for a variety of air flow rates and bubble injection depths. Also, computed bubble rise velocity is compared to a well-accepted expression for bubble terminal velocity.

A Longitudinal Motor Characterisation of the HdhQ111 Mouse Model of Huntington's Disease.

Science.gov (United States)

Yhnell, Emma; Dunnett, Stephen B; Brooks, Simon P

2016-05-31

Huntington's disease (HD) is a rare, incurable neurodegenerative disorder caused by a CAG trinucleotide expansion with the first exon of the huntingtin gene. Numerous knock-in mouse models are currently available for modelling HD. However, before their use in scientific research, these models must be characterised to determine their face and predictive validity as models of the disease and their reliability in recapitulating HD symptoms. Manifest HD is currently diagnosed upon the onset of motor symptoms, thus we sought to longitudinally characterise the progression and severity of motor signs in the HdhQ111 knock-in mouse model of HD, in heterozygous mice. An extensive battery of motor tests including: rotarod, inverted lid test, balance beam, spontaneous locomotor activity and gait analysis were applied longitudinally to a cohort of HdhQ111 heterozygous mice in order to progressively assess motor function. A progressive failure to gain body weight was demonstrated from 11 months of age and motor problems in all measures of balance beam performance were shown in HdhQ111 heterozygous animals in comparison to wild type control animals from 9 months of age. A decreased latency to fall from the rotarod was demonstrated in HdhQ111 heterozygous animals in comparison to wild type animals, although this was not progressive with time. No genotype specific differences were demonstrated in any of the other motor tests included in the test battery. The HdhQ111 heterozygous mouse demonstrates a subtle and progressive motor phenotype that begins at 9 months of age. This mouse model represents an early disease stage and would be ideal for testing therapeutic strategies that require elongated lead-in times, such as viral gene therapies or striatal transplantation.

Improvement of database on glass dissolution

International Nuclear Information System (INIS)

Hayashi, Maki; Sasamoto, Hiroshi; Yoshikawa, Hideki

2008-03-01

In geological disposal system, high-level radioactive waste (HLW) glass is expected to retain radionuclide for the long term as the first barrier to prevent radionuclide release. The advancement of its performance assessment technology leads to the reliability improvement of the safety assessment of entire geological disposal system. For this purpose, phenomenological studies for improvement of scientific understanding of dissolution/alteration mechanisms, and development of robust dissolution/alteration model based on the study outcomes are indispensable. The database on glass dissolution has been developed for supporting these studies. This report describes improvement of the prototype glass database. Also, this report gives an example of the application of the database for reliability assessment of glass dissolution model. (author)

Early stage of weathering of medieval-like potash-lime model glass: evaluation of key factors.

Science.gov (United States)

Gentaz, Lucile; Lombardo, Tiziana; Loisel, Claudine; Chabas, Anne; Vallotto, Marta

2011-02-01

Throughout history, a consequent part of the medieval stained glass windows have been lost, mostly because of deliberate or accidental mechanic destruction during war or revolution, but, in some cases, did not withstand the test of time simply because of their low durability. Indeed, the glasses that remain nowadays are for many in a poor state of conservation and are heavily deteriorated. Under general exposure conditions, stained glass windows undergo different kinds of weathering processes that modify their optical properties, chemistry, and structure: congruent dissolution, leaching, and particle deposition (the combination of those two leading together to the formation of neocrystallisations and eventually crusts). Previous research has studied the weathering forms and the mechanisms from which they are originated, some others identified the main environmental parameters responsible for the deterioration and highlighted that both intrinsic (glass composition) and extrinsic (environmental parameters) factors influence glass degradation. Nevertheless, a clear quantification of the impact of the different deterioration extrinsic factors has not been performed. By analysing the results obtained with model glass (durable and nondurable) exposed in the field, this paper proposes a simple mathematical computation evaluating the contribution of the different weathering factors for the early stages of exposure of the stained glasses. In the case of non durable glass, water runoff was identified as the main factor inducing the leaching (83.4 ± 2.6% contribution), followed by gas (6.4 ± 1.5%) and particle deposition (6.8 ± 2.2%) and adsorbed water (3.4 ± 0.6%). Moreover, it was shown that the extrinsic stimuli superimposes with the impact of glass composition to the weathering. Those results show that the role played by dry deposition, even if less important than that of the wet deposition, cannot be neglected.

Modelling of the controlled melt flow in a glass melting space – Its melting performance and heat losses

Czech Academy of Sciences Publication Activity Database

Jebavá, Marcela; Dyrčíková, Petra; Němec, Lubomír

2015-01-01

Roč. 430, DEC 15 (2015), s. 52-63 ISSN 0022-3093 Institutional support: RVO:67985891 Keywords : glass melt flow * mathematical modelling * energy distribution * space utilizatios * melting performance Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 1.825, year: 2015

Quality assurance of 137Cs Photons for Vivo Mouse Irradiation System

International Nuclear Information System (INIS)

Noh, S. J.; Kim, H. J.; Jeong, D. H.; Yang, K. M.; Son, T. G.; Kang, Y. R.; Shin, S. G.; Kye, Y. U.

2014-01-01

The multi-purpose irradiation apparatus using a 137 Cs, which can be used for the blood test, can be affected by the other components of the experiments such as the size and shape of the beaker and the maximum variation of more than 35% has been reported. The mount of the absorbed dose is determined by the distance between irradiation target and the source and the irradiation time with the irradiator (Gamma Irradiator, Chiyoda Technol Co, Japan) for this experiment. The low-dose irradiation has been used in this study is advantageous for irradiating the cell culture vessel or the small animal. However, radiation is performed by placing the 3-5 mice in each mouse cage (polycarbonate cage). In this case, overlapping often happens to the target during irradiation. Irradiating without considering the geometrical aspect of the irradiation device can occur as well. To solve the problems, the mouse apartment with the 45 mouse cages is built and the device is assessed by being compared with the conventional method in 2 different ways. Firstly, the glass dosimeters were inserted into the head and the body of the lab mice for 2 methods. Secondly, MCNP simulation was performed for absorbed dose and air kerma measurements in each mouse apartment chamber. In this study, the system that allows the accurate irradiation using the 137 Cs gamma irradiator mainly used in Radiation Biology was developed and the accuracy of the system has been confirmed by the experiments. The dose delivery using the conventional system had the variation of 42% at most whereas the variation was less than 6% for the mouse apartment. From the MCNP simulation, the difference between each chamber was less than 0.1% and 0.4% for the air kerma and the absorbed dose respectively. Considering the statistical error of MCNP and the assumption from the simulation, the accuracy of the simulation was matched well with the measurements with the glass dosimeters

Some recent developments in spin glasses

Indian Academy of Sciences (India)

I give some experimental and theoretical background to spin glasses, and then discuss the nature of the phase transition in spin glasses with vector spins. Results of Monte Carlo simulations of the Heisenberg spin glass model in three dimensions are presented. A finite-size scaling analysis of the correlation length of the ...

Thermokinetic model of borosilicate glass dissolution: Contextual affinity

International Nuclear Information System (INIS)

Advocat, T.; Vernaz, E.; Crovisier, J.L.; Fritz, B.

1990-01-01

Short and long-term geochemical interactions of R7T7 nuclear glass with water at 100C were simulated with the DISSOL thermokinetic computer code. Both the dissolved glass quantity and the resulting water composition, saturation states and mineral quantities produced were calculated as a function of time. The rate equation used in the simulation was first proposed by Aagaard and Hegelson: v = k + · S · a( H + ) -n · (1 - e -(A/RT) ). It simulates a gradually diminishing dissolution rate as the reaction affinity diminishes. The best agreement with 1-year experimental data was obtained with a reaction affinity calculated from silica activity (Grambow's hypothesis) rather than taking into account the activity of all the glass components as proposed by Jantzen and Plodinec. The concept of residual affinity was introduced by Grambow to express the fact that the glass dissolution rate does not cease. The authors prefer to replace the term residual affinity by contextual affinity, which expresses the influence on the dissolution rate of three factors: the solution chemistry, the metastability of SiO 2 (m), and the possible precipitation of certain aluminosilicates such as zeolites

Use of mouse thigh as a radiobiological model of radiation-induced skin reactions

International Nuclear Information System (INIS)

Smith, A.J.; Hagkyriakou, H.; Martin, R.F.

2000-01-01

Full text: The effects of radiation exposure on skin have been widely studied. One of the most useful and relatively easy methods for evaluating radiation-induced skin reactions is the mouse thigh model. This model is non-invasive and has the advantage of not requiring the use of anaesthetic. In the current adaptation of the mouse thigh model, female C3H/HeJ ARC mice (from the Animal Resource Centre, W.A.) were used. The mice were restrained in specially designed jigs where the right leg was held in place by a metal hook. Lead shielding ensured that only the right ventral thigh was exposed to the radiation beam. A 6MeV electron beam from a Varian 2100 Linac (20Gy / minute) was used, thus minimising the time for which the mice were restrained. Eight to twelve days after exposure to the radiation, the first skin reactions can be seen. These are scored according to a scale ranging from 0 (no visible reaction) to 3.5 (breakdown of the entire area with severe exudation). The skin reactions (erythema and moist desquamation) peak approximately 18-22 days after radiation exposure and may remain at peak for only 1-3 days. Therefore, the reactions need to be scored daily and this continues, generally until day 35, or until all moist desquamation has healed. The maximum score in a score versus time profile for each mouse in a group of 5-6 animals are averaged. Radiation-dose response data will be presented. Using the mouse thigh model, hair loss can also be measured (usually on about day 30-35) using a scale from 0-4, where 0 depicts no evident hair loss and 4 represents complete epilation. Leg contraction can also be measured as a late effect by comparison with the length of the unirradiated leg

Imaging noradrenergic influence on amyloid pathology in mouse models of Alzheimer's disease

International Nuclear Information System (INIS)

Winkeler, A.; Waerzeggers, Y.; Klose, A.; Monfared, P.; Thomas, A.V.; Jacobs, A.H.; Schubert, M.; Heneka, M.T.

2008-01-01

Molecular imaging aims towards the non-invasive characterization of disease-specific molecular alterations in the living organism in vivo. In that, molecular imaging opens a new dimension in our understanding of disease pathogenesis, as it allows the non-invasive determination of the dynamics of changes on the molecular level. The imaging technology being employed includes magnetic resonance imaging (MRI) and nuclear imaging as well as optical-based imaging technologies. These imaging modalities are employed together or alone for disease phenotyping, development of imaging-guided therapeutic strategies and in basic and translational research. In this study, we review recent investigations employing positron emission tomography and MRI for phenotyping mouse models of Alzheimers' disease by imaging. We demonstrate that imaging has an important role in the characterization of mouse models of neurodegenerative diseases. (orig.)

Entropic vs. elastic models of fragility of glass-forming liquids: Two sides of the same coin?

Science.gov (United States)

Sen, Sabyasachi

2012-10-01

The two most influential atomistic models that have been proposed in the literature to explain the temperature dependent activation energy of viscous flow of a glass-forming liquid, i.e., its fragility, are the configurational entropy model of Adam and Gibbs [J. Chem. Phys. 43, 139 (1965), 10.1063/1.1696442] and the elastic "shoving" model of Dyre et al. [J. Non-Cryst. Solids 352, 4635 (2006), 10.1016/j.jnoncrysol.2006.02.173]. Here we demonstrate a qualitative equivalence between these two models starting from the well-established general relationships between the interatomic potentials, elastic constants, structural rearrangement, and entropy in amorphous materials. The unification of these two models provides important predictions that are consistent with experimental observations and shed new light into the problem of glass transition.

An athymic mouse model to mimic cobalt-60 cutaneous radiation injury

Energy Technology Data Exchange (ETDEWEB)

Mosca, Rodrigo Crespo; Ferreira, Danilo Cardenuto; Napolitano, Celia Marina; Santin, Stefany Plumeri; Dornelles, Leonardo Dalla Porta; Alvarenga, Eluara Ortigoso; Mathor, Monica Beatriz, E-mail: rcmosca@usp.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2013-07-01

Propose: Cutaneous wound from irradiation is the most common complication in radiotherapy treatment, and can be lead to mortality. We describe an athymic mouse model to mimic cutaneous radiation injury by Cobalt-60. Methods: A protocol was including dosimetry with silicon diodes,10x10x5 cm arrangement made by four lead bricks and PVC pipe designed to immobilize the athymic mouse in order to irradiate one clamped back skin point that was subdivided in four parts. To get the measurements of dose rates on the arrangement in Panoramic Irradiator, it was used a silicon diode encased in an opaque protection for ambient light and connected to an electric cable, forming a dosing probe. The currents generated in diode sensitive volume as a function of time of exposure to gamma radiation coming from the radiator, with dose rate of 0,015 Gy/min in positions 1, 0,021 Gy/min in position 2, 0,55 Gy/min in position 3 and 1,45 Gy/min in position four. After the dosimetry, each athymic mouse was anesthetized using Xylazine and Ketamine dilution and entered into a PVC pipe and a small portion of skin (1 cm{sup 3}) was clamped. This tube was then fixed to arrangement and the athymic mouse was irradiate for 60 min, than it was being returned to its cage. Results: The wound was visualized in all animals and photographed after 5 days of irradiation, with the emergence of ulceration after 9 days. No systemic or lethal sequelae occurred or visualized in any animals. Late clinical signs included a wound healing after 22 days. Conclusion: While still being a baseline study, we created a new functional preclinical animal model that can be used for new therapies and may improve radiotherapy management. (author)

An athymic mouse model to mimic cobalt-60 cutaneous radiation injury

International Nuclear Information System (INIS)

Mosca, Rodrigo Crespo; Ferreira, Danilo Cardenuto; Napolitano, Celia Marina; Santin, Stefany Plumeri; Dornelles, Leonardo Dalla Porta; Alvarenga, Eluara Ortigoso; Mathor, Monica Beatriz

2013-01-01

Propose: Cutaneous wound from irradiation is the most common complication in radiotherapy treatment, and can be lead to mortality. We describe an athymic mouse model to mimic cutaneous radiation injury by Cobalt-60. Methods: A protocol was including dosimetry with silicon diodes,10x10x5 cm arrangement made by four lead bricks and PVC pipe designed to immobilize the athymic mouse in order to irradiate one clamped back skin point that was subdivided in four parts. To get the measurements of dose rates on the arrangement in Panoramic Irradiator, it was used a silicon diode encased in an opaque protection for ambient light and connected to an electric cable, forming a dosing probe. The currents generated in diode sensitive volume as a function of time of exposure to gamma radiation coming from the radiator, with dose rate of 0,015 Gy/min in positions 1, 0,021 Gy/min in position 2, 0,55 Gy/min in position 3 and 1,45 Gy/min in position four. After the dosimetry, each athymic mouse was anesthetized using Xylazine and Ketamine dilution and entered into a PVC pipe and a small portion of skin (1 cm 3 ) was clamped. This tube was then fixed to arrangement and the athymic mouse was irradiate for 60 min, than it was being returned to its cage. Results: The wound was visualized in all animals and photographed after 5 days of irradiation, with the emergence of ulceration after 9 days. No systemic or lethal sequelae occurred or visualized in any animals. Late clinical signs included a wound healing after 22 days. Conclusion: While still being a baseline study, we created a new functional preclinical animal model that can be used for new therapies and may improve radiotherapy management. (author)

Replica analysis of partition-function zeros in spin-glass models

International Nuclear Information System (INIS)

Takahashi, Kazutaka

2011-01-01

We study the partition-function zeros in mean-field spin-glass models. We show that the replica method is useful to find the locations of zeros in a complex parameter plane. For the random energy model, we obtain the phase diagram in the plane and find that there are two types of distributions of zeros: two-dimensional distribution within a phase and one-dimensional one on a phase boundary. Phases with a two-dimensional distribution are characterized by a novel order parameter defined in the present replica analysis. We also discuss possible patterns of distributions by studying several systems.

Apollo 12 ropy glasses revisited

Science.gov (United States)

Wentworth, S. J.; Mckay, D. S.; Lindstrom, D. J.; Basu, A.; Martinez, R. R.; Bogard, D. D.; Garrison, D. H.

1994-01-01

We analyzed ropy glasses from Apollo 12 soils 12032 and 12033 by a variety of techniques including SEM/EDX, electron microprobe analysis, INAA, and Ar-39-Ar-40 age dating. The ropy glasses have potassium rare earth elements phosphorous (KREEP)-like compositions different from those of local Apollo 12 mare soils; it is likely that the ropy glasses are of exotic origin. Mixing calculations indicate that the ropy glasses formed from a liquid enriched in KREEP and that the ropy glass liquid also contained a significant amount of mare material. The presence of solar Ar and a trace of regolith-derived glass within the ropy glasses are evidence that the ropy glasses contain a small regolith component. Anorthosite and crystalline breccia (KREEP) clasts occur in some ropy glasses. We also found within these glasses clasts of felsite (fine-grained granitic fragments) very similar in texture and composition to the larger Apollo 12 felsites, which have a Ar-39-Ar-40 degassing age of 800 +/- 15 Ma. Measurements of 39-Ar-40-Ar in 12032 ropy glass indicate that it was degassed at the same time as the large felsite although the ropy glass was not completely degassed. The ropy glasses and felsites, therefore, probably came from the same source. Most early investigators suggested that the Apollo 12 ropy glasses were part of the ejecta deposited at the Apollo 12 site from the Copernicus impact. Our new data reinforce this model. If these ropy glasses are from Copernicus, they provide new clues to the nature of the target material at the Copernicus site, a part of the Moon that has not been sampled directly.

DWPF GLASS BEADS AND GLASS FRIT TRANSPORT DEMONSTRATION

Energy Technology Data Exchange (ETDEWEB)

Adamson, D; Bradley Pickenheim, B

2008-11-24