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Sample records for replaces aggregated states

  1. performance of concrete with partial replacement of fine aggregates ...

    African Journals Online (AJOL)

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    Key Words: compressive strength, concrete, crushed waste glass, flexural strength, setting time, water absorption and workability. ... powder as partial replacement of fine aggregates up to ... water in cement paste and reactive silica in the WG.

  2. Acid Resistance of Concrete Containing Laterite Aggregate as Partial Coarse Aggregate Replacement

    Directory of Open Access Journals (Sweden)

    K. Muthusamy

    2014-05-01

    Full Text Available In Malaysia, issues of granite aggregate depletion in future due to increasing use in concrete industry and the availability of laterite aggregate locally has initiated studies on concrete produced using laterite aggregate as partial coarse aggregate replacement. Although, replacement of laterite aggregate up to 30% able to produce concrete with the targeted strength but durability of this concrete towards acid attack yet to be investigated. Thus, this study presents and discusses the performance of concrete consisting various percentage of laterite aggregate integrated as partial coarse aggregate replacement upon exposure to acidic environment. Mixes consisting various content of laterite aggregate as partial coarse aggregate replacement ranging from 0, 10, 20, 30, 40 and 50%, respectively were prepared in form of cubes and then subjected to water curing for 28 days before immersed in hydrochloric acid solution for 1800 h. Performance of the specimens were observed through mass loss and strength reduction. Generally, durability performance of concrete produced using up to 20% of laterite aggregate is comparable to plain concrete.

  3. Properties of Concrete with Tire Derived Aggregate Partially Replacing Coarse Aggregates

    Science.gov (United States)

    Siringi, Gideon; Abolmaali, Ali; Aswath, Pranesh B.

    2015-01-01

    Tire derived aggregate (TDA) has been proposed as a possible lightweight replacement for mineral aggregate in concrete. The role played by the amount of TDA replacing coarse aggregate as well as different treatment and additives in concrete on its properties is examined. Conventional concrete (without TDA) and concrete containing TDA are compared by examining their compressive strength based on ASTM C39, workability based on ASTM C143, splitting tensile strength based on ASTM C496, modulus of rupture (flexural strength) based on ASTM C78, and bond stress based on ASTM C234. Results indicate that while replacement of coarse aggregates with TDA results in reduction in strength, it may be mitigated with addition of silica fume to obtain the desired strength. The greatest benefit of using TDA is in the development of a higher ductile product while utilizing recycled TDA. PMID:26161440

  4. Properties of Concrete with Tire Derived Aggregate Partially Replacing Coarse Aggregates

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    Gideon Siringi

    2015-01-01

    Full Text Available Tire derived aggregate (TDA has been proposed as a possible lightweight replacement for mineral aggregate in concrete. The role played by the amount of TDA replacing coarse aggregate as well as different treatment and additives in concrete on its properties is examined. Conventional concrete (without TDA and concrete containing TDA are compared by examining their compressive strength based on ASTM C39, workability based on ASTM C143, splitting tensile strength based on ASTM C496, modulus of rupture (flexural strength based on ASTM C78, and bond stress based on ASTM C234. Results indicate that while replacement of coarse aggregates with TDA results in reduction in strength, it may be mitigated with addition of silica fume to obtain the desired strength. The greatest benefit of using TDA is in the development of a higher ductile product while utilizing recycled TDA.

  5. Properties of Concrete with Tire Derived Aggregate Partially Replacing Coarse Aggregates.

    Science.gov (United States)

    Siringi, Gideon; Abolmaali, Ali; Aswath, Pranesh B

    2015-01-01

    Tire derived aggregate (TDA) has been proposed as a possible lightweight replacement for mineral aggregate in concrete. The role played by the amount of TDA replacing coarse aggregate as well as different treatment and additives in concrete on its properties is examined. Conventional concrete (without TDA) and concrete containing TDA are compared by examining their compressive strength based on ASTM C39, workability based on ASTM C143, splitting tensile strength based on ASTM C496, modulus of rupture (flexural strength) based on ASTM C78, and bond stress based on ASTM C234. Results indicate that while replacement of coarse aggregates with TDA results in reduction in strength, it may be mitigated with addition of silica fume to obtain the desired strength. The greatest benefit of using TDA is in the development of a higher ductile product while utilizing recycled TDA.

  6. Strength Characteristics of Concrete with Partial Replacement of Coarse Aggregate By Laterite Stone and Fine Aggregate by Quarry Dust

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    M. Venkata Rao

    2016-10-01

    Full Text Available This paper presents the results of concrete mix with partial replacement of fine aggregate by quarry dust and simultaneous partial replacement of coarse aggregate by laterite stone aggregate respectively on compressive strength, split tensile strength, flexural strength and workability of concrete. Concrete mixes containing 0%, 10%, 20%, 25 % and 30%, replacement (by weight of fine aggregate with quarry dust and simultaneously 25% replacement of coarse aggregate (by weight with laterite stone were casted in lab and checked for compressive strength, split tensile strength ,flexure strength and workability .This replacement results in making the concrete more economically available.

  7. Natural aggregate totally replacement by mechanically treated concrete waste

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    Junak Jozef

    2015-06-01

    Full Text Available This paper presents the results obtained from the research focused on the utilization of crushed concrete waste aggregates as a partial or full replacement of 4/8 and 8/16 mm natural aggregates fraction in concrete strength class C 16/20. Main concrete characteristics such as workability, density and compressive strength were studied. Compressive strength testing intervals for samples with recycled concrete aggregates were 2, 7, 14 and 28 days. The amount of water in the mixtures was indicative. For mixture resulting consistency required slump grade S3 was followed. Average density of all samples is in the range of 2250 kg/m3 to 2350 kg/m3. The highest compressive strength after 28 days of curing, 34.68 MPa, reached sample, which contained 100% of recycled material in 4/8 mm fraction and 60% of recycled aggregates in 8/16 mm fraction. This achieved value was only slightly different from the compressive strength 34.41 MPa of the reference sample.

  8. Natural aggregates of the conterminous United States

    Science.gov (United States)

    Langer, William H.

    1988-01-01

    Crushed stone and sand and gravel are the two main sources of natural aggregates. These materials are commonly used construction materials and frequently can be interchanged with one another. They are widely used throughout the United States, with every State except two producing crushed stone. Together they amount to about half the mining volume in the United States. Approximately 96 percent of sand and gravel and 77 percent of the crushed stone produced in the United States are used in the construction industry. Natural aggregates are widely distributed throughout the United States in a variety of geologic environments. Sand and gravel deposits commonly are the results of the weathering of bedrock and subsequent transportation and deposition of the material by water or ice (glaciers). As such, they commonly occur as river or stream deposits or in glaciated areas as glaciofluvial and other deposits. Crushed stone aggregates are derived from a wide variety of parent bedrock materials. Limestone and other carbonates account for approximately three quarters of the rocks used for crushed stone, with granite and other igneous rocks making up the bulk of the remainder. Limestone deposits are widespread throughout the Central and Eastern United States and are scattered in the West. Granites are widely distributed in the Eastern and Western United States, with few exposures in the Midwest. Igneous rocks (excluding granites) are largely concentrated in the Western United States and in a few isolated localities in the East. Even though natural aggregates are widely distributed throughout the United States, they are not universally available for consumptive use. Some areas are devoid of sand and gravel, and potential sources of crushed stone may be covered with sufficient unconsolidated material to make surface mining impractical. In some areas many aggregates do not meet the physical property requirements for certain uses, or they may contain mineral constituents that react

  9. Excited-state dynamics of astaxanthin aggregates

    Science.gov (United States)

    Fuciman, Marcel; Durchan, Milan; Šlouf, Václav; Keşan, Gürkan; Polívka, Tomáš

    2013-05-01

    Astaxanthin forms three types of aggregates in hydrated dimethyl sulfoxide (DMSO). In DMSO/water ratio of 1:1, a red-shifted J-aggregate with maximum at 570 nm is generated, while a ratio of 1:9 produces blue-shifted H-aggregates with peaks at 386 nm (H1) and 460 nm (H2). Monomeric astaxanthin in DMSO has an S1 lifetime of 5.3 ps, but a long-lived (33 ps) S∗ signal was also identified. Aggregation changes the S1 lifetimes to 17 ps (H1), 30 ps (H2), and 14 ps (J). Triplet state of astaxanthin, most likely generated via singlet homofission, was observed in H1 and H2 aggregates.

  10. Low aggregation state diminishes ferrihydrite reactivity

    Science.gov (United States)

    Braunschweig, Juliane; Heister, Katja; Meckenstock, Rainer U.

    2013-04-01

    Ferrihydrite is an abundant iron(oxy)hydroxide in soils and sediments and plays an important role in microbial iron cycling due to its high reactivity. Therefore, it is often synthesized and used in geomicrobiological and mineralogical studies. The reactivities of synthetic ferrihydrites vary between different studies and synthesis protocols. Hence, we synthesized five different ferrihydrites and characterized them with XRD, FTIR, XPS, and BET specific surface area. The reactivity of the ferrihydrite samples towards ascorbic acid was examined and compared with microbial reduction rates by Geobacter sulfurreducens. FTIR and XRD results show the presence of secondary, higher crystalline iron oxide phases like goethite and akaganeite for two samples. Consequently, those samples revealed lower biotic and abiotic reduction rates compared to pure ferrihydrite. Comparison of reduction rates with the specific surface area of all ferrihydrites showed neither correlation with abiotic reductive dissolution nor with microbial reduction. Especially one sample, characterized by a very low aggregation state and presence of secondary minerals, revealed a poor reactivity. We speculate that apart from the occurring secondary minerals also the low aggregation state played an important role. Decreasing aggregation diminishes the amount of kinks and edges on the surfaces, which are produced at contact sites in aggregates. According to dissolution theories, dissolution mainly starts at those surface defects and slows down with decreasing amount of defects. Furthermore, the non-aggregated ferrihydrite is free of micropores, a further stimulant for dissolution. Independent repetitions of experiments and syntheses according to the same protocol but without formation of secondary minerals, confirmed the low reactivity of the non-aggregated ferrihydrite. In summary, our results indicate that a decreasing aggregation state of ferrihydrite to a certain size does increase the reactivity

  11. The Feasibility of Palm Kernel Shell as a Replacement for Coarse Aggregate in Lightweight Concrete

    Science.gov (United States)

    Itam, Zarina; Beddu, Salmia; Liyana Mohd Kamal, Nur; Ashraful Alam, Md; Issa Ayash, Usama

    2016-03-01

    Implementing sustainable materials into the construction industry is fast becoming a trend nowadays. Palm Kernel Shell is a by-product of Malaysia’s palm oil industry, generating waste as much as 4 million tons per annum. As a means of producing a sustainable, environmental-friendly, and affordable alternative in the lightweight concrete industry, the exploration of the potential of Palm Kernel Shell to be used as an aggregate replacement was conducted which may give a positive impact to the Malaysian construction industry as well as worldwide concrete usage. This research investigates the feasibility of PKS as an aggregate replacement in lightweight concrete in terms of compressive strength, slump test, water absorption, and density. Results indicate that by using PKS for aggregate replacement, it increases the water absorption but decreases the concrete workability and strength. Results however, fall into the range acceptable for lightweight aggregates, hence it can be concluded that there is potential to use PKS as aggregate replacement for lightweight concrete.

  12. Laboratory Investigation Of Partial Replacement Of Coarse Aggregate By Plastic Chips And Cement By Human Hair

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    A.S.Balaji

    2014-04-01

    Full Text Available The use of plastic is increasing day by day, although steps were taken to reduce its consumption. The suitability of recycled plastics as coarse aggregate in concrete and its advantage are discussed here. Experimental investigation was done using M20 mix and tests were carried out as per recommended procedures by relevant codes. As 100% replacement of natural coarse aggregate (NCA with plastic coarse aggregate (PCA is not feasible, partial replacement were examined. And also Hair is used as a fibred reinforcing material in concrete as partial replacement of cement. It has a high tensile strength which is equal to that of a copper wire with similar diameter. It is also available in abundance and at a very low cost. Tests were conducted to determine the properties of plastic aggregate and human hair such as density, specific gravity and crushing value. Experiments were conducted on concrete cubes with various percentages of human hair i.e. 0%, 0.5%, 1%, 1.5%, 2%, and 3% by weight of cement and with constant percentage of plastic aggregate as 20%.

  13. Mechanical evaluation of asphalt-aggregate mixtures prepared with fly ash as a filler replacement

    Energy Technology Data Exchange (ETDEWEB)

    Tapkin, T. [Anadolu Univ., Eskisehir (Turkey). Dept. of Civil Engineering

    2008-01-15

    This paper examined methods of introducing fly ash waste products as a filler in asphalt concrete mixtures. A literature review of studies involving fly ash and asphalts was conducted. The effect of fly ash filler replacements on the mechanical properties of asphalt-aggregate mixtures was investigated. A dense bituminous calcareous aggregate was used as a reference mixture for a series of tests. Three types of fly ash were investigated, notably (1) portland cement; (2) lime; and (3) control specimens. Changes in elastic strain, elastic modulus, and permanent strain properties of the asphalt mixtures were determined through a series of fatigue tests. The behaviour of the asphalt concrete pavements were analyzed under applied loads. Results of the tests showed that the fatigue life of the fly ash specimens was higher than the calcareous aggregate specimens. It was concluded that fly ash can used as a filler replacement for dense-graded wearing courses. 35 refs., 17 tabs., 8 figs.

  14. Study on Behaviour of Concrete Mix Replaceing Fine Aggregate With Steel Slag At Different Properties

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    P.Sateesh Kumar

    2015-11-01

    Full Text Available This paper aims to study experimentally, the effect of partial replacement of fine aggregate by steel slag (ss, on the various strength and durability properties of concrete by using the mix designs .the optimum percentage of replacement of fine aggregate by steel slag is found. Workability of concrete gradually decreases, as the percentage of replacement increases which is found using slump test. Compressive strength, tensile strength, flexural strength and durability tests such as acid resistant’s, using HCL,H2SO4 and rapid chloride penetration, are experimentally investigated. The results indicate that for conventional concrete, partial replacement of concrete by steel slag improves the compressive, tensile, flexural strength. The mass loss in cubes after immersion in acids is found to be very low. Deflection in the RCC beams gradually increases, as the load on the beam increases, for the replacement. The degree of fluoride ion penetrability is assessed based on the limits given in ASTM C 1202. The viability of use of steel slag in concrete is found. Waste management is one of the most common and challenging problems in the world. The steel making industry has generated substantially solid waste. Steel slag is a residue obtained in steel making operation. This paper deals with the implementation of steel slag as an effective replacement for sand. Steel slag ,which is consider as the solid waste pollutant, can be used for road construction ,clinker raw materials, filling materials etc. In this work, steel slag used as replacement for sand, which is also major component concrete mixture. This method can be implement for producing hallow blocks, solid blocks, paver blocks, concrete structures etc. Accordingly, advantages can be achieved by using steel slag instead of natural aggregates this will also encourage other researchers to find another field of using steel slag.

  15. Exploratory Study of Palm Oil Fuel Ash as Partial Cement Replacement in Oil Palm Shell Lightweight Aggregate Concrete

    OpenAIRE

    Muthusamy, K.; Z. Nur Azzimah

    2014-01-01

    In Malaysia, issue of environmental pollution resulting from disposal of Palm Oil Fuel Ash (POFA) which is a by-product from palm oil mill has initiated research to incorporate this waste in Oil Palm Shell (OPS) lightweight aggregate concrete production. The current study investigates the effect of palm oil fuel ash content as partial cement replacement towards compressive strength OPS lightweight aggregate concrete. Several OPS lightweight aggregate concrete mixes were produced by replacing ...

  16. Performance Degradation of the Repeated Recycled Aggregate Concrete with 70% Replacement of Three-generation Recycled Coarse Aggregate

    Institute of Scientific and Technical Information of China (English)

    ZHU Pinghua; ZHANG Xinxin; WU Junyong; WANG Xinjie

    2016-01-01

    The feasibility of using different generations recycled coarse aggregate (RCA) on structural concrete was fully evaluated by studying the performance of the recycled coarse aggregates and their corresponding concretes, the different generations of RCA were recycled by following the repeated mode of ‘concrete-waste concrete-coarse aggregate-concrete’. Moreover, the focus was on ‘three generations’ of repeated RCAs, the RCA was produced by crushing and regenerating the artiifcial accelerated degraded concrete, the process was designed to follow the nature degradation of the concrete with a coupling action of accelerated carbonation and bending load. The properties ofx-generation (x=1, 2 or 3) of repeated RCA were systematically investigated and the compressive and splitting tensile strengths of relating structural concretes(with 70% replacement ofx-generation of RCA) were studied accordingly. The results show a competent compressive and splitting tensile strength of 30 MPa at 28th day of structural concretes with all generations of repeated RAC. And the gradual degraded performance of the repeated RCAs was observed with an increased numbers of repetition (1﹥2﹥3 generations), the overall performances of all repeated RCAs fulifll the ClassⅢaccording to Chinese Standards GB25177-2010. Our gained insight demonstrates a feasibility of using at least 3 generations of repeated RCA for the production of normal structural concrete.

  17. Early age shrinkage pattern of concrete on replacement of fine aggregate with industrial by-product

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    R.K. Mishra

    2016-10-01

    Full Text Available This is an experimental work carried out to investigate early age shrinkage pattern of concrete, prepared, on 50% replacement of industrial by-product (like pond ash and granulated blast furnace slag as fine aggregate using OPC, PPC and PSC as a binder. This is to observe the effect of pond ash and slag as they are having some cementitious properties and effect of cement type is also discussed. All the mixes were prepared keeping in view of pumpable concrete without any super plasticizers. Higher shrinkage value indicates the presence of more bleed water or internal moisture. It is concluded that slag is the best option for fine aggregate replacement for concrete making and durable structure.

  18. Exploratory Study of Rubber Seed Shell as Partial Coarse Aggregate Replacement in Concrete

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    K. Muthusamy

    2014-02-01

    Full Text Available Malaysia being a major rubber trees growing country has been generating a large amount of rubber seed shell which regarded as waste. At the same time, the growing construction industry which boosts the concrete production trade has results in higher consumption of natural coarse aggregate which open the door for depletion of this material in future. This study focuses on investigating the possibility of integrating crushed rubber seed shell as partial coarse aggregate replacement material in concrete making. Total of five mixes consisting various content of crushed rubber seed shell as partial coarse aggregate replacement ranging from 0, 5, 10, 15 and 20%, respectively were prepared in form of cubes. All the specimens were water cured before tested at 7 and 28 days. The workability test, compressive strength test and flexural strength test of the mixes was conducted in accordance to MS26 Part 1: Section 2, BSEN 12390 and ASTM 293-79 respectively. Generally, workability, compressive strength and flexural strength decrease with the increase in the crushed rubber seed shell replacement level. However, mix consisting around 10% of crushed rubber seed shell is suitable for the application in concrete work.

  19. Study on Strength of Concrete Using Robo Sand as a Partial Replacement of Fine Aggregate

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    S.Rukmangadhara Rao,

    2015-12-01

    Full Text Available Robo sand is one of the most used among such materials to replace river sand, which can be used as an alternative to fine aggregate in concrete. In the present investigation workability and strength of concrete was evaluated by replacement of natural sand by Robo sand in proportions of 0%, 50%, 75%, and 100% is studied for M25and M35grade concrete cubes, cylinders and prisms. Slump cone method is taken for finding workability. For strength parameters for each grade of concrete Cubes, Cylinders and Prisms were casted and tested at the age of 7 and 28 days. In this present experimental study on concrete having grades of M25 and M35 are prepared by replacing natural sand by Robo sand. Concrete specimens were tested for evaluation of compressive strength and water absorption.

  20. Polymer Waste Material as Partial Replacement of Fine Aggregate in Concrete Production

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    D. Dahiru

    2014-05-01

    Full Text Available The aim of the study is to assess the quality of concrete produced with polymer waste as partial replacement of fine aggregate with a view to establishing areas where such concrete can be used. It is an experimental research that entails the following steps: First, the polymer waste material, PWM, was collected from dumps and processed; then its melting point determined. A varying proportion of PWM was used as partial replacement of fine aggregate A nominal mix of 1:3:6 was used to prepare 150×150×150 mm concrete cubes specimens with different proportion of 0, 10, 20 and 30%, respectively PWM partial substitution of fine aggregate. Samples were subjected to workability, compressive and tensile strength tests. Results show that PWM content has inverse relationship with the workability, compressive and tensile strengths. For example, an increase of 30% PWM results to about 53 and 73.3% decrease in compressive and tensile strengths, respectively. The compressive strength of the samples is in the range of 22.8-12.3 N/mm2 while the tensile strength ranges from 1.10-0.56 N/mm2. It is recommended that the concrete should not be used for structural work but such concrete has high water retention capacity. As such, the possibility of using it as a nuclear radiation shield should be investigated.

  1. Durability and acoustics of concrete with slag of cupola furnace as fine aggregate replacement

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    Ricardo Alfredo Cruz Hernández

    2015-01-01

    Full Text Available In this paper, it was evaluated the performance of concrete with crushed slag of cupola furnace (SCF as sand replacement in percentages of 0 %, 10 %, 15 % and 20 %, subjected to accelerated chemical attacks of carbonation, sulfation and alkali-aggregate reaction (AAR. The sound absorption characteristics of the material were determined through the sound absorption coefficient (α, and the noise reduction coefficient (NRC. Carbonation was evaluated through a closed camera with the 70 % concentration of carbon dioxide and conditions of relative humidity between 50 % and 70 %. The results indicated that the penetration depth of CO2 is lower when greater the percentage of substitution is. To accelerate the attack by sulfates, specimens were immersed in aqueous solution of sodium sulfate anhydrous (Na2SO4 1N with cycles of wetting and drying. It determined that the impairment presented in concrete paste is directly proportional to the percentage of sand replacement. The acceleration of the AAR in the concrete was carried out by immersing specimens in an aqueous solution of sodium hydroxide (NaOH for 16 days. The test concluded that the inclusion of SCF is not favorable for AAR. The measurement of sound absorption coefficient was taken by the method of impedance tube, relating minimum and maximum values of stationary wave amplitude. The results showed that SCF with higher sand replacement are favorable for the noise absorption in buildings.

  2. High performance of treated and washed MSWI bottom ash granulates as natural aggregate replacement within earth-moist concrete.

    Science.gov (United States)

    Keulen, A; van Zomeren, A; Harpe, P; Aarnink, W; Simons, H A E; Brouwers, H J H

    2016-03-01

    Municipal solid waste incineration bottom ash was treated with specially designed dry and wet treatment processes, obtaining high quality bottom ash granulate fractions (BGF) suitable for up to 100% replacement of natural gravel in concrete. The wet treatment (using only water for separating and washing) significantly lowers the leaching of e.g. chloride and sulfate, heavy metals (antimony, molybdenum and copper) and dissolved organic carbon (DOC). Two potential bottom ash granulate fractions, both in compliance with the standard EN 12620 (aggregates for concrete), were added into earth-moist concrete mixtures. The fresh and hardened concrete physical performances (e.g. workability, strength and freeze-thaw) of high strength concrete mixtures were maintained or improved compared with the reference mixtures, even after replacing up to 100% of the initial natural gravel. Final element leaching of monolithic and crushed granular state BGF containing concretes, showed no differences with the gravel references. Leaching of all mixtures did not exceed the limit values set by the Dutch Soil Quality Degree. In addition, multiple-life-phase emission (pH static test) for the critical elements of input bottom ash, bottom ash granulate (BGF) and crushed BGF containing concrete were assessed. Simulation pH lowering or potential carbonation processes indicated that metal (antimony, barium, chrome and copper) and sulfate element leaching behavior are mainly pH dominated and controlled, although differ in mechanism and related mineral abundance.

  3. Study of Compressive Strength of Concrete with Coal Power Plant Fly Ash as Partial Replacement of Cement and Fine Aggregate

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    FAREED AHMED MEMON

    2010-10-01

    Full Text Available This research study comprises of concrete cubes made with Ordinary Portland Cement and with different configurations of fly ash by replacing cement and fine aggregate. To achieve the aim of this study, total 81 concrete cubes were cast. Among 81 cubes, 9 cubes were made with normal concrete, 36 cubes were made by replacing 25%, 50%, 75% and 100% of fine aggregate with fly ash and 36 cubes were made by replacing 10%, 25%, 50%, and 75% of cement with fly ash. The cubes were 6\\" x 6\\" in cross-section, and the mix design was aimed for 5000 psi. After proper curing of all 81 cubes, they were tested at 3, 7 and 28 days curing age. The cubes were tested in Forney Universal Testing Machine. By analyzing the test results of all the concrete cubes, the following main findings have been drawn. The compressive strength of concrete cubes made by replacing 100 % fine aggregate by fly ash was higher than the concrete cubes made with Ordinary Portland Cement at all 3, 7 and 28 days curing ages. On the other hand, the compressive strength of concrete cubes made by replacing 10 % and 25 % cement by fly ash was slightly lower than the concrete cubes made with Ordinary Portland Cement at all curing ages, whereas, the compressive strength of concrete cubes made by replacing 50 % and 75 % of cement by fly ash were quite lower than the concrete cubes made with Ordinary Portland Cement at all curing ages.

  4. Exploratory Study of Palm Oil Fuel Ash as Partial Cement Replacement in Oil Palm Shell Lightweight Aggregate Concrete

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    K. Muthusamy

    2014-07-01

    Full Text Available In Malaysia, issue of environmental pollution resulting from disposal of Palm Oil Fuel Ash (POFA which is a by-product from palm oil mill has initiated research to incorporate this waste in Oil Palm Shell (OPS lightweight aggregate concrete production. The current study investigates the effect of palm oil fuel ash content as partial cement replacement towards compressive strength OPS lightweight aggregate concrete. Several OPS lightweight aggregate concrete mixes were produced by replacing various percentage of POFA ranging from 10, 20, 30, 40 and 50%, respectively by weight of cement. All the mixes were cast in form of cubes and then subjected to water curing until the testing date. The compressive strength test is conducted in accordance to BSEN 12390 (2009 at 7 and 28 days. From the results, it was observed that the combination of appropriate POFA content would enhance the compressive strength of OPS lightweight aggregate concrete. Specimen produced using 20% POFA as partial cement replacement exhibit higher value of compressive strength than that of control OPS lightweight aggregate concrete. However, mixes consisting POFA up to 50% is also suitable for structural application.

  5. Sustainable use of industrial-waste as partial replacement of fine aggregate for preparation of concrete – A review

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    Manoj Kumar Dash

    2016-12-01

    Full Text Available Utilisation of industrial waste materials in concrete compensates the lack of natural resources, solving the disposal problem of waste and to find alternative technique to safeguard the nature. There are a number of industrial wastes used as fully or partial replacement of coarse aggregate or fine aggregate. This review carries out a thorough assessment about industrial waste substances, which can be adequately utilised in concrete as fine aggregate substitution. This paper reviewed some of these industrial wastes like waste foundry sand, steel slag, copper slag, imperial smelting furnace slag (ISF slag, blast furnace slag, coal bottom ash, ferrochrome slag, palm oil clinker etc. Out of these materials, maximum number of experiments have been conducted using waste foundry sand and copper slag as fine aggregate replacement, but still more examinations are required for other waste materials as replacement of sand in concrete. Different physical and mechanical properties of industrial waste as well as of industrial waste concrete, in which natural sand is substituted have been reviewed and comparisons are made between them. Deflection and leaching study review are carried out additionally and compared. It can be observed that the concrete where sand is replaced by copper slag, imperial smelting furnace slag, class F fly ash exhibits improved strength and durability properties, but it’s slump increases as the rate of replacement increases in the case of copper slag and the slump decreases in the case of class F fly ash. There is a less research work reported on ferrochrome slag and palm oil clinker used as sand substitution, so it is felt that further detailed investigations are required.

  6. Solid State Replacement of Rotating Mirror Cameras

    Energy Technology Data Exchange (ETDEWEB)

    Frank, A M; Bartolick, J M

    2006-08-25

    Rotating mirror cameras have been the mainstay of mega-frame per second imaging for decades. There is still no electronic camera that can match a film based rotary mirror camera for the combination of frame count, speed, resolution and dynamic range. The rotary mirror cameras are predominantly used in the range of 0.1 to 100 micro-seconds per frame, for 25 to more than a hundred frames. Electron tube gated cameras dominate the sub microsecond regime but are frame count limited. Video cameras are pushing into the microsecond regime but are resolution limited by the high data rates. An all solid state architecture, dubbed ''In-situ Storage Image Sensor'' or ''ISIS'', by Prof. Goji Etoh, has made its first appearance into the market and its evaluation is discussed. Recent work at Lawrence Livermore National Laboratory has concentrated both on evaluation of the presently available technologies and exploring the capabilities of the ISIS architecture. It is clear though there is presently no single chip camera that can simultaneously match the rotary mirror cameras, the ISIS architecture has the potential to approach their performance.

  7. A [Mn18Dy] SMM resulting from the targeted replacement of the central MnII in the S = 83/2 [Mn19]-aggregate with DyIII.

    Science.gov (United States)

    Ako, Ayuk M; Mereacre, Valeriu; Clérac, Rodolphe; Wernsdorfer, Wolfgang; Hewitt, Ian J; Anson, Christopher E; Powell, Annie K

    2009-02-07

    Anisotropy can be introduced into the [Mn(19)]-aggregate, which currently has the highest known spin ground state of S = 83/2, by the targeted replacement of the central Mn(II) cation with Dy(III) leading to a [Mn(18)Dy] complex with the same core topology showing slow relaxation of the magnetisation.

  8. Transcending the replacement paradigm of solid-state lighting.

    Science.gov (United States)

    Kim, Jong Kyu; Schubert, E Fred

    2008-12-22

    The field of photonics starts with the efficient generation of light. The generation of efficient yet highly controllable light can indeed be accomplished with light-emitting diodes (LEDs), which are, in principle, capable of generating white light with a 20 times greater efficiency than conventional light bulbs. Deployed on a global scale to replace conventional sources, such solid-state light sources will result in enormous benefits that, over a period of 10 years, include (1) gigantic energy savings of 1.9 x 1020 joule, (2) a very substantial reduction in global-warming CO2 emissions, (3) a strong reduction in the emission of pollutants such as acid-rain-causing SO2, mercury (Hg), and uranium (U), and (4) financial savings exceeding a trillion (10(12)) US$. These benefits can be accomplished by the "replacement paradigm" in which conventional light sources are replaced by more energy efficient, more durable, and non-toxic light sources. However, it will be shown that solid-state light sources can go beyond the replacement paradigm, by providing new capabilities including the control of spectrum, color temperature, polarization, temporal modulation, and spatial emission pattern. We will show that such future, "smart" light sources, can harness the huge potential of LEDs by offering multi-dimensional controllability that will enhance the functionality and performance of light sources in a wide range of applications. These applications include optical microscopy, imaging, display technologies, communications, networking, and transportation systems.

  9. Replacement of Natural Fine Aggregate With Air Cooled Blast Furnace Slag An Industrial By Product

    Directory of Open Access Journals (Sweden)

    Dr. B. Krishna Rao

    2015-07-01

    Full Text Available The aim of the investigation is to replace natural fine aggregatewith Air Cooled Blast Furnace Slag in OPC concrete. At present, nearly million tons of slag is being produced in the steel plants, in India. The generation of slag would be dual problem in disposal difficulty and environmental pollution. Some strategies should be used to utilize the slag effectively. Considering physical properties of metallurgical slags and a series of possibilities for their use in the field of civil constructions, this report demonstrates the possibilities of using air cooled blast furnace slag as partial replacement of sand in concrete. A total of five concrete mixes, containing 0%, 12.5%, 25%, 37.5% and 50% partial replacement of regular sand with air cooled blast furnace slag are investigated in the laboratory. These mixes were tested to determine axial compressive strength, split tensile strength, and flexural strength for 7days, 28days, 56days and 90days.

  10. Influence of Bottom Ash Replacements as Fine Aggregate on the Property of Cellular Concrete with Various Foam Contents

    Directory of Open Access Journals (Sweden)

    Patchara Onprom

    2015-01-01

    Full Text Available This research focuses on evaluating the feasibility of utilizing bottom ash from coal burning power plants as a fine aggregate in cellular concrete with various foam contents. Flows of all mixtures were controlled within 45 ± 5% and used foam content at 30%, 40%, 50%, 60%, and 70% by volume of mixture. Bottom ash from Mae Moh power plant in Thailand was used to replace river sand at the rates of 0%, 25%, 50%, 75%, and 100% by volume of sand. Compressive strength, water absorption, and density of cellular concretes were determined at the ages of 7, 14, and 28 days. Nonlinear regression technique was developed to construct the mathematical models for predicting the compressive strength, water absorption, and density of cellular concrete. The results revealed that the density of cellular concrete decreased while the water absorption increased with an increase in replacement level of bottom ash. From the experimental results, it can be concluded that bottom ash can be used as fine aggregate in the cellular concrete. In addition, the nonlinear regression models give very high degree of accuracy (R2>0.99.

  11. Replacement

    Directory of Open Access Journals (Sweden)

    S. Radhakrishnan

    2014-03-01

    Full Text Available The fishmeal replaced with Spirulina platensis, Chlorella vulgaris and Azolla pinnata and the formulated diet fed to Macrobrachium rosenbergii postlarvae to assess the enhancement ability of non-enzymatic antioxidants (vitamin C and E, enzymatic antioxidants (superoxide dismutase (SOD and catalase (CAT and lipid peroxidation (LPx were analysed. In the present study, the S. platensis, C. vulgaris and A. pinnata inclusion diet fed groups had significant (P < 0.05 improvement in the levels of vitamins C and E in the hepatopancreas and muscle tissue. Among all the diets, the replacement materials in 50% incorporated feed fed groups showed better performance when compared with the control group in non-enzymatic antioxidant activity. The 50% fishmeal replacement (best performance diet fed groups taken for enzymatic antioxidant study, in SOD, CAT and LPx showed no significant increases when compared with the control group. Hence, the present results revealed that the formulated feed enhanced the vitamins C and E, the result of decreased level of enzymatic antioxidants (SOD, CAT and LPx revealed that these feeds are non-toxic and do not produce any stress to postlarvae. These ingredients can be used as an alternative protein source for sustainable Macrobrachium culture.

  12. Will mineral trioxide aggregate replace calcium hydroxide in treating pulpal and periodontal healing complications subsequent to dental trauma?

    DEFF Research Database (Denmark)

    Bakland, Leif K; Andreasen, Jens O

    2012-01-01

    Mineral trioxide aggregate (MTA) has over the last two decades begun to take the place of calcium hydroxide (CH) in the treatment of a variety of pulpal and periodontal healing complications following dental trauma. These conditions include teeth with: (i) exposed pulps, (ii) immature roots...... and pulp necrosis, (iii) root fractures and pulp necrosis located in the coronal part of the pulps, and (iv) external infection-related (inflammatory) root resorption. The main reasons for replacing CH with MTA in these situations have generally been the delayed effect when using CH to induce hard tissues......, the quality of such induced hard tissues, and finally the dentin weakening effect of CH, which in some instances lead to cervical root fractures in immature teeth. MTA appears, from a relatively few clinical studies, to overcome these shortcomings of CH. The lack of long-term clinical studies, however, may...

  13. Lightweight concrete with Algerian limestone dust. Part II: study on 50% and 100% replacement to normal aggregate at timely age

    Directory of Open Access Journals (Sweden)

    S. Kitouni

    2015-12-01

    Full Text Available Abstract A control lightweight concrete (LWC mixture made with 50% and 100% of limestone as a replacement of coarse aggregates in weight was prepared. Limestone is used for economical and environmental concern. The concrete samples were cured at 65% relative humidity at 20 ºC. The compressive and flexural tensile strengths, elastic modulus and Poisson's ratio of hardened concrete were measured. Laboratory compressive and tensile strength tests results showed that LWC can be produced by the use of limestone. The aim of this study is twofold: one is to design a lightweight concrete with the use of limestone that will provide an advantage of reduction in dead weight of a structure; and second is to obtain a more economical LWC mixture with the use of limestone.

  14. Review: Application of coal bottom ash as aggregate replacement in highway embankment, acoustic absorbing wall and asphalt mixtures

    Science.gov (United States)

    Afiza Mohammed, Syakirah; Rehan Karim, Mohamed

    2017-06-01

    Worldwide annual production of coal bottom ash waste was increased in the last decade and is being dumped on landfill over the years. Its improper disposal has become an environmental concern and resulted in a waste of recoverable resources. There is a pressing and on-going need to develop new recycling methods for coal bottom ash. The utilization of coal bottom ash in highway engineering is one of the options to reduce the environmental problems related to the disposal of bottom ash. The present review describe the physical and chemical properties of coal bottom ash waste and its current application as highway embankment material, as acoustic absorbing material and as aggregate replacement in asphalt mixtures. The purpose of this review is to stimulate and promote the effective recycling of coal bottom ash in highway engineering industry.

  15. Will mineral trioxide aggregate replace calcium hydroxide in treating pulpal and periodontal healing complications subsequent to dental trauma? A review.

    Science.gov (United States)

    Bakland, Leif K; Andreasen, Jens O

    2012-02-01

    Mineral trioxide aggregate (MTA) has over the last two decades begun to take the place of calcium hydroxide (CH) in the treatment of a variety of pulpal and periodontal healing complications following dental trauma. These conditions include teeth with: (i) exposed pulps, (ii) immature roots and pulp necrosis, (iii) root fractures and pulp necrosis located in the coronal part of the pulps, and (iv) external infection-related (inflammatory) root resorption. The main reasons for replacing CH with MTA in these situations have generally been the delayed effect when using CH to induce hard tissues, the quality of such induced hard tissues, and finally the dentin weakening effect of CH, which in some instances lead to cervical root fractures in immature teeth. MTA appears, from a relatively few clinical studies, to overcome these shortcomings of CH. The lack of long-term clinical studies, however, may warrant a certain reservation in an unrestricted replacement of CH with MTA. A definite need for randomized clinical studies comparing CH and MTA in trauma healing situations is urgently needed.

  16. A Study on Suitability of EAF Oxidizing Slag in Concrete: An Eco-Friendly and Sustainable Replacement for Natural Coarse Aggregate

    Directory of Open Access Journals (Sweden)

    Alan Sekaran

    2015-01-01

    Full Text Available Environmental and economic factors increasingly encourage higher utility of industrial by-products. The basic objective of this study was to identify alternative source for good quality aggregates which is depleting very fast due to fast pace of construction activities in India. EAF oxidizing slag as a by-product obtained during the process in steel making industry provides great opportunity to utilize it as an alternative to normally available coarse aggregates. The primary aim of this research was to evaluate the physical, mechanical, and durability properties of concrete made with EAF oxidizing slag in addition to supplementary cementing material fly ash. This study presents the experimental investigations carried out on concrete grades of M20 and M30 with three mixes: (i Mix A, conventional concrete mix with no material substitution, (ii Mix B, 30% replacement of cement with fly ash, and (iii Mix C, 30% replacement of cement with fly ash and 50% replacement of coarse aggregate with EAF oxidizing slag. Tests were conducted to determine mechanical and durability properties up to the age of 90 days. The test results concluded that concrete made with EAF oxidizing slag and fly ash (Mix C had greater strength and durability characteristics when compared to Mix A and Mix B. Based on the overall observations, it could be recommended that EAF oxidizing slag and fly ash could be effectively utilized as coarse aggregate replacement and cement replacement in all concrete applications.

  17. A Study on Suitability of EAF Oxidizing Slag in Concrete: An Eco-Friendly and Sustainable Replacement for Natural Coarse Aggregate.

    Science.gov (United States)

    Sekaran, Alan; Palaniswamy, Murthi; Balaraju, Sivagnanaprakash

    2015-01-01

    Environmental and economic factors increasingly encourage higher utility of industrial by-products. The basic objective of this study was to identify alternative source for good quality aggregates which is depleting very fast due to fast pace of construction activities in India. EAF oxidizing slag as a by-product obtained during the process in steel making industry provides great opportunity to utilize it as an alternative to normally available coarse aggregates. The primary aim of this research was to evaluate the physical, mechanical, and durability properties of concrete made with EAF oxidizing slag in addition to supplementary cementing material fly ash. This study presents the experimental investigations carried out on concrete grades of M20 and M30 with three mixes: (i) Mix A, conventional concrete mix with no material substitution, (ii) Mix B, 30% replacement of cement with fly ash, and (iii) Mix C, 30% replacement of cement with fly ash and 50% replacement of coarse aggregate with EAF oxidizing slag. Tests were conducted to determine mechanical and durability properties up to the age of 90 days. The test results concluded that concrete made with EAF oxidizing slag and fly ash (Mix C) had greater strength and durability characteristics when compared to Mix A and Mix B. Based on the overall observations, it could be recommended that EAF oxidizing slag and fly ash could be effectively utilized as coarse aggregate replacement and cement replacement in all concrete applications.

  18. An Investigation into the Use of Manufactured Sand as a 100% Replacement for Fine Aggregate in Concrete

    Directory of Open Access Journals (Sweden)

    Martins Pilegis

    2016-06-01

    Full Text Available Manufactured sand differs from natural sea and river dredged sand in its physical and mineralogical properties. These can be both beneficial and detrimental to the fresh and hardened properties of concrete. This paper presents the results of a laboratory study in which manufactured sand produced in an industry sized crushing plant was characterised with respect to its physical and mineralogical properties. The influence of these characteristics on concrete workability and strength, when manufactured sand completely replaced natural sand in concrete, was investigated and modelled using artificial neural networks (ANN. The results show that the manufactured sand concrete made in this study generally requires a higher water/cement (w/c ratio for workability equal to that of natural sand concrete due to the higher angularity of the manufactured sand particles. Water reducing admixtures can be used to compensate for this if the manufactured sand does not contain clay particles. At the same w/c ratio, the compressive and flexural strength of manufactured sand concrete exceeds that of natural sand concrete. ANN proved a valuable and reliable method of predicting concrete strength and workability based on the properties of the fine aggregate (FA and the concrete mix composition.

  19. An FTIR study on the chlorophyll and apoprotein aggregation states in LHCII due to solvent effects

    CSIR Research Space (South Africa)

    Smit, Jacoba E

    2012-07-01

    Full Text Available Photosynthesis provides us with the most abundant and efficient light-harvesting systems found in nature. The photosynthetic process is very much dependent on the aggregation state of the chlorophylls and secondary conformational structure...

  20. Distribution and Aggregate Thickness of Salt Deposits of the United States

    Data.gov (United States)

    U.S. Environmental Protection Agency — The map shows the distribution and aggregate thickness of salt deposits of the United States. This information is from contour map sheets, scanned and processed for...

  1. Serum replacement with albumin-associated lipids prevents excess aggregation and enhances growth of induced pluripotent stem cells in suspension culture.

    Science.gov (United States)

    Horiguchi, Ikki; Sakai, Yasuyuki

    2016-07-08

    Suspension culture systems are currently under investigation for the mass production of pluripotent stem (PS) cells for tissue engineering; however, the control of cell aggregation in suspension culture remains challenging. Existing methods to control aggregation such as microwell culture are difficult to scale up. To address this issue, in this study a novel method that incorporates the addition of KnockOut Serum Replacement (KSR) to the PS cell culture medium was described. The method regulated cellular aggregation and significantly improved cell growth (a 2- to 10-fold increase) without any influence on pluripotency. In addition, albumin-associated lipids as the major working ingredient of KSR responsible for this inhibition of aggregation were identified. This is one of the simplest methods described to date to control aggregation and requires only chemically synthesizable reagents. Thus, this method has the potential to simplify the mass production process of PS cells and thus lower their cost. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1009-1016, 2016.

  2. Influence of denatured and intermediate states of folding on protein aggregation.

    Science.gov (United States)

    Fawzi, Nicolas L; Chubukov, Victor; Clark, Louis A; Brown, Scott; Head-Gordon, Teresa

    2005-04-01

    We simulate the aggregation thermodynamics and kinetics of proteins L and G, each of which self-assembles to the same alpha/beta [corrected] topology through distinct folding mechanisms. We find that the aggregation kinetics of both proteins at an experimentally relevant concentration exhibit both fast and slow aggregation pathways, although a greater proportion of protein G aggregation events are slow relative to those of found for protein L. These kinetic differences are correlated with the amount and distribution of intrachain contacts formed in the denatured state ensemble (DSE), or an intermediate state ensemble (ISE) if it exists, as well as the folding timescales of the two proteins. Protein G aggregates more slowly than protein L due to its rapidly formed folding intermediate, which exhibits native intrachain contacts spread across the protein, suggesting that certain early folding intermediates may be selected for by evolution due to their protective role against unwanted aggregation. Protein L shows only localized native structure in the DSE with timescales of folding that are commensurate with the aggregation timescale, leaving it vulnerable to domain swapping or nonnative interactions with other chains that increase the aggregation rate. Folding experiments that characterize the structural signatures of the DSE, ISE, or the transition state ensemble (TSE) under nonaggregating conditions should be able to predict regions where interchain contacts will be made in the aggregate, and to predict slower aggregation rates for proteins with contacts that are dispersed across the fold. Since proteins L and G can both form amyloid fibrils, this work also provides mechanistic and structural insight into the formation of prefibrillar species.

  3. The State Policy on Modernization of the Aggregate Financial Potential of Ukraine

    Directory of Open Access Journals (Sweden)

    Portna Oksana V.

    2016-05-01

    Full Text Available The aim of the article is to give a definition of “modernization of the aggregate financial potential of the country”, substantiate the directions and ways of the state policy on modernization of the aggregate financial potential of Ukraine. On the basis of the analysis, systematization and generalization of approaches to different kinds and types of modernization in the financial and economic sphere and its application to the constituents of the aggregate financial capacity of the country, it has been determined that the essence of the modernization of the country’s aggregate financial potential is in its renewal due to the disclosure of its structure, functions and mechanisms of implementation aimed at ensuring stable development of the national economy. According to the study results there have been proposed government measures to modernize the aggregate financial potential of Ukraine, including a complex system for stabilization of the national economy. The modernization paradigm implies an interconnected role of the system constituents that form the resource environment for ensuring the functioning of the national financial and economic sphere. Directions and ways of the state policy on modernization of the aggregate financial potential of Ukraine have a complex character both as a means of combating the existing financial and economic imbalances and from the standpoint of the requirements and expectations of society and of each economic entity. Prospects for further research in this direction are measures of the state policy on the expanded reproduction of the aggregate financial potential of Ukraine

  4. Lightweight concrete with Algerian limestone dust: Part I: Study on 30% replacement to normal aggregate at early age

    Directory of Open Access Journals (Sweden)

    S. Kitouni

    2013-12-01

    Full Text Available The mechanical characteristics of the lightweight aggregate concretes (LWAC strongly depend on the proportions of aggregates in the formulation. In particular, because of their strong porosity, the lightweight aggregates are much more deformable than the cementations matrix and their influence on concrete strength is complex. This paper focuses on studying the physical performance of concrete formulated with substitution of 30% of coarse aggregates by limestone dust. In this article an attempt is made to provide information on the elastic properties of lightweight concrete (LWC from tests carried out under uniaxial compression conditions. The results of Young modulus, Poisson's ratio, and compressive and flexural tensile strength tests on concrete are presented. The concretes obtained present good mechanical performances reaching 34.99 MPa compressive strength, 6.39 MPa flexural tensile strength and in front of 36 MPa Young modulus.

  5. Early aggregated States in the folding of interleukin-1β.

    Science.gov (United States)

    Finke, J M; Jennings, P A

    2001-06-01

    Kinetic data measured from folding of the protein interleukin-1β fits best to three exponential phases when studied with tryptophan fluorescence but only two exponential phases when measured using other methods. The technique of ANS fluorescence was used to determine whether the additional phase observed in tryptophan fluorescence was also detected with ANS dye binding. Unlike trytophan fluorescence, the ANS fluorescence was highly dependent on the concentration of protein present during the folding experiment. Experimental controls provide evidence that ANS binds to protein aggregates, present at higher concentrations and absent at lower concentrations. Protein concentration-dependent folding studies demonstrate that, at lower interleukin-1β concentrations, tryptophan fluorescence kinetics can be fit adequately with a two exponential fit. This study indicates that (1) measured interleukin-1β folding kinetics fit to a 2 phase model and (2) at higher protein concentrations, transient association of IL-1β may result in a kinetic fit of 3 phases.

  6. Characterization of insulin-degrading enzyme-mediated cleavage of Aβ in distinct aggregation states.

    Science.gov (United States)

    Hubin, Ellen; Cioffi, Federica; Rozenski, Jef; van Nuland, Nico A J; Broersen, Kerensa

    2016-06-01

    To enhance our understanding of the potential therapeutic utility of insulin-degrading enzyme (IDE) in Alzheimer's disease (AD), we studied in vitro IDE-mediated degradation of different amyloid-beta (Aβ) peptide aggregation states. Our findings show that IDE activity is driven by the dynamic equilibrium between Aβ monomers and higher ordered aggregates. We identify Met(35)-Val(36) as a novel IDE cleavage site in the Aβ sequence and show that Aβ fragments resulting from IDE cleavage form non-toxic amorphous aggregates. These findings need to be taken into account in therapeutic strategies designed to increase Aβ clearance in AD patients by modulating IDE activity.

  7. Assessment of Concrete Strength Using Partial Replacement of Coarse Aggregate for Wast Tiles and Cement for Rice Husk Ash in Concrete

    Directory of Open Access Journals (Sweden)

    Umapathy U

    2014-05-01

    Full Text Available Conservation of natural resources and preservation of environment is the essence of any development. The problem arising from continuous technological and industrial development is the disposal of waste material. If some of the waste materials are found suitable in concrete making, not only cost of construction can be cut down, but also safe disposal of waste materials can be achieved. So in our project, an attempt has been made to assess the suitability of stone with waste tills in concrete making. In the laboratory tiles has been tried as coarse aggregate has been used as partial substitute to conventional coarse aggregate concrete making and today many researches are ongoing into the use of Portland cement replacements, using many waste materials like pulverized fly ash (PFA and ground granulated blast furnace slag (GGBS. Like PFA and GGBS a waste glass powder (GLP is also used as a binder with partial replacement of cement which takes some part of reaction at the time of hydration. In this study, rice husk ash have been used as partially replacements to the cement Cubes were cast and tested for compressive strength, and modulus of rupture after a curing period of 7,17,28 days.

  8. New Insights on US Aggregate and State Level Trade with the China Region%New Insights on US Aggregate and State Level Trade with the China Region

    Institute of Scientific and Technical Information of China (English)

    Catherine Y. Co

    2011-01-01

    Aggregate trade data with breakdown into related and non-related party components show that US multinational enterprises use different trading strategies in the China region relative to other countries. US trade with the China region in 2002-007 is characterized by arm 's- length transactions. State-level trade data show great variability in state engagement with the region through trade: exports to the region range from 1 to 28 percent of state exports. In addition, compared to exports to other countries, exports to the region are highly concentrated. At the extreme, for some states, 96-98 percent of exports to the region are computer and electronic products. Finally, gravity regressions show that state exports to Hong Kong are posflively associated with the relative size of the ltong Kong-born population in the states. There is no evidence that stricter labor regimes lead to lower state exports.

  9. Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates

    KAUST Repository

    Zhao, Kui

    2016-07-13

    We demonstrate that local and long range orders of poly(3-hexylthiophene) (P3HT) semicrystalline films can be synergistically improved by combining chemical functionalization of the dielectric surface with solution-state disentanglement and pre-aggregation of P3HT in a theta solvent, leading to a very significant enhancement of the field effect carrier mobility. The pre-aggregation and surface functionalization effects combine to enhance the carrier mobility nearly 100-fold as compared with standard film preparation by spin-coating, and nearly 10-fold increase over the benefits of pre-aggregation alone. In situ quartz crystal microbalance with dissipation (QCM-D) experiments reveal enhanced deposition of pre-aggregates on surfaces modified with an alkyl-terminated self-assembled monolayer (SAM) in comparison to un-aggregated polymer chains. Additional investigations reveal the combined pre-aggregation and surface functionalization significantly enhances local order of the conjugated polymer through planarization and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor-dielectric interface in organic thin film transistors. This study points to opportunities in combining complementary routes, such as well-known pre-aggregation with substrate chemical functionalization, to enhance the polymer self-assembly and improve its interfacial order with benefits for transport properties.

  10. Innovative Solid State Lighting Replacements for Industrial and Test Facility Locations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed effort will develop a solid-state LED replacement lamp for rocket engine test stand lighting and more general hazardous-location lighting. The LED...

  11. 再生骨料取代率对再生混凝土物理力学性能的影响%Impact of Recycled Aggregate's Replacement Rate on Physical and Mechanical Properties of Recycled Aggregate Concrete

    Institute of Scientific and Technical Information of China (English)

    陈国慧; 彭泽艳

    2014-01-01

    Taking ordinary concrete C30 as the benchmark, technological indexed like water absorption, water-binder ratio, slump,strength,apparent densi-ty and cracking index of natural aggregate concrete and recycled aggregate concrete are respectively measured with experiment. The impact of different replacement rates of recycled aggregate on its mixture and physical and mechanical properties in settling and hardening process are also studied with com-parative analysis method.%以C30普通混凝土为基准,通过实验分别测定天然骨料和再生骨料混凝土吸水率、水胶比、坍落度、强度、表观密度、开裂指数等技术指标,运用对比分析法研究再生骨料不同取代率对再生混凝土拌合物及其凝结硬化过程物理力学性能的影响。

  12. Replacement Capability Options for the United States Space Shuttle

    Science.gov (United States)

    2013-09-01

    first designed for reuse ” (NASA, 2000). 1. United States Space Shuttle Program (1981–2011) The first operational Space Shuttle was Columbia (OV-102...Week article on China’s future plans for their Long March Launch vehicles, “China is developing three basic rocket modules, with diameters of 2.25... wastewater , which will burn up with the spacecraft when it re-enters the Earth’s atmosphere. The Cargo Module can hold 1,000 to 1,700 kilograms (2,205

  13. 40 CFR 63.1221 - What are the replacement standards for hazardous waste burning lightweight aggregate kilns?

    Science.gov (United States)

    2010-07-01

    ... Hazardous Waste Combustors Replacement Emissions Standards and Operating Limits for Incinerators, Cement.... You must not discharge or cause combustion gases to be emitted into the atmosphere or feed hazardous... corrected to 7 percent oxygen; or (ii) Rapid quench of the combustion gas temperature at the exit of...

  14. State aggregation and population dynamics in linear systems.

    Science.gov (United States)

    Rowe, Jonathan E; Vose, Michael D; Wright, Alden H

    2005-01-01

    We consider complex systems that are composed of many interacting elements, evolving under some dynamics. We are interested in characterizing the ways in which these elements may be grouped into higher-level, macroscopic states in a way that is compatible with those dynamics. Such groupings may then be thought of as naturally emergent properties of the system. We formalize this idea and, in the case that the dynamics are linear, prove necessary and sufficient conditions for this to happen. In cases where there is an underlying symmetry among the components of the system, group theory may be used to provide a strong sufficient condition. These observations are illustrated with some artificial life examples.

  15. An Enhancement of the Replacement Steady State Genetic Algorithm for Intrusion Detection

    Directory of Open Access Journals (Sweden)

    Reyadh Naoum

    2014-06-01

    Full Text Available In these days, Internet and computer systems face many intrusions, thus for this purpose we need to build a detection or prevention security system. Intrusion Detection System (IDS is a system used to detect attacks, Steady State Genetic Algorithm (SSGA is applied to support IDS by supplying the rule pool with additional data, these data can be used in testing phase to detect the attacks. The main goal of this research is to enhance Replacement steady state genetic algorithm to detect intrusions. This enhancement has been achieved by comparing replacement methods. This research proved that the Triple Tournament Replacement is better than Binary Tournament Replacement to increase Detection Rate and there are no effects on False Positive Rate. In this research represent the results of DR equal 100% for three types of attack (DoS, Probe and R2T, and 53% for U2R.

  16. Aggregating Student Achievement Trends across States with Different Tests: Using Standardized Slopes as Effect Sizes

    Science.gov (United States)

    Yin, Robert K.; Schmidt, R. James; Besag, Frank

    2006-01-01

    The study of federal education initiatives that takes place over multiple years in multiple settings often calls for aggregating and comparing data-in particular, student achievement data-across a broad set of schools, districts, and states. The need to track the trends over time is complicated by the fact that the data from the different schools,…

  17. Inflation asymmetry, menu costs and aggregation bias – A further case for state dependent pricing

    OpenAIRE

    Karádi, Péter; Reiff, Ádám

    2010-01-01

    Asymmetric inflation response to aggregate shocks is an identifying macro-prediction of state dependent pricing models with trend inflation (Ball and Mankiw, 1994). The paper uses the natural experiment of symmetric value-added tax (VAT) changes in Hungary with highly asymmetric inflation responses to provide further evidence for state-dependent pricing and for the Ball-Mankiw conjecture. The paper shows, furthermore, that while a standard menu cost model like that of Golosov and Lucas (2007)...

  18. Mechanical properties of structural concrete with partial replacement of fine aggregate by tire rubber - doi: 10.4025/actascitechnol.v35i1.11283

    Directory of Open Access Journals (Sweden)

    Laura Granzotto

    2013-01-01

    Full Text Available The urbanization of big cities, the reduced number and size of landfills, the population growth rate, and the increased use of disposables have generated an expressive volume of waste in the environment. Some waste materials have been reused in recent years, as for example, those generated by the civil construction. However, other types of waste are not experiencing the same situation, such as tire rubbers. One alternative for the reutilization of this material consists of using their powder to replace the fine aggregate in the composition of concrete. This study presents experiments on normal strength concrete mixed with different rates of rubber powder. Results reveal the possibility of obtaining an optimum rate of powder incorporation without harming the compressive and tensile strength of concrete.  

  19. 再生粗骨料取代率对混凝土各项性能的影响%Effects of Replacement Ratio of Recycled Coarse Aggregate on Properties of Concrete

    Institute of Scientific and Technical Information of China (English)

    全洪珠; 袁传鹏; 迟玉锦

    2011-01-01

    利用不同品质的3种再生粗骨料,研究了再生粗骨料取代率对混凝土的工作性能、力学性能及干缩性能的影响.结果表明,利用再生粗骨料取代碎石,高品质再生粗骨料可以使碎石混凝土的性能得到改善,而低品质再生粗骨料则降低碎石混凝土的性能,且再生粗骨料取代率不宜超过50%.%By using three different quality recycled coarse aggregates,this paper presents the effects of the replacement ratio of recycled coarse aggregate on the properties of work,mechanics and drying shrinkage of concrete.The results show that if the recycled coarse aggregate is used to replace gravel,the high-quality recycled coarse aggregate can improve the properties of gravel concrete and the low-quality recycled coarse aggregate can reduce the properties of gravel concrete,and the replacement ratio of recycled coarse aggregate should not exceed 50%.

  20. Ferromagnetic resonance in Ni-Zn ferrite nanoparticles in different aggregation states

    Energy Technology Data Exchange (ETDEWEB)

    Valenzuela, Raul, E-mail: monjaras@servidor.unam.mx [Departamento de Materiales Metalicos y Ceramicos, Universidad Nacional Autonoma de Mexico, Mexico D.F. 04510 (Mexico); Herbst, Frederic; Ammar, Souad [ITODYS, UMR-CNRS 7086, Universite de Paris-Diderot, 75205 Paris Cedex (France)

    2012-10-15

    Ferrite nanoparticles of composition Zn{sub 0.5}Ni{sub 0.5}Fe{sub 2}O{sub 4} were synthesized by forced hydrolysis in polyol from the corresponding zinc, nickel and iron acetates. By varying the preparation conditions, different aggregation states were obtained, ranging from isolated nanoparticles with average diameter of 5 nm, to clusters of some 20 nm, formed as well by nanoparticles with average diameter in the 5 nm range, as confirmed by X-ray diffraction and high resolution transmission electron microscopy. Ferromagnetic resonance measurements exhibited a ferrimagnetic behavior for both aggregation states at 77 K; at 300 K, however, isolated nanoparticles showed a superparamagnetic behavior while clustered ones remained ferrimagnetic with a broad linewidth. These results are interpreted on the basis of interactions between nanoparticles.

  1. Chapter K: Progress in the Evaluation of Alkali-Aggregate Reaction in Concrete Construction in the Pacific Northwest, United States and Canada

    Science.gov (United States)

    Shrimer, Fred H.

    2005-01-01

    The supply of aggregates suitable for use in construction and maintenance of infrastructure in western North America is a continuing concern to the engineering and resources-management community. Steady population growth throughout the region has fueled demand for high-quality aggregates, in the face of rapid depletion of existing aggregate resources and slow and difficult permitting of new sources of traditional aggregate types. In addition to these challenges, the requirement for aggregates to meet various engineering standards continues to increase. In addition to their physical-mechanical properties, other performance characteristics of construction aggregates specifically depend on their mineralogy and texture. These properties can result in deleterious chemical reactions when aggregate is used in concrete mixes. When this chemical reaction-termed 'alkali-aggregate reaction' (AAR)-occurs, it can pose a major problem for concrete structures, reducing their service life and requiring expensive repair or even replacement of the concrete. AAR is thus to be avoided in order to promote the longevity of concrete structures and to ensure that public moneys invested in infrastructure are well spent. Because the AAR phenomenon is directly related to the mineral composition, texture, and petrogenesis of the rock particles that make up aggregates, an understanding of the relation between the geology and the performance of aggregates in concrete is important. In the Pacific Northwest, some aggregates have a moderate to high AAR potential, but many others have no or only a low AAR potential. Overall, AAR is not as widespread or serious a problem in the Pacific Northwest as in other regions of North America. The identification of reactive aggregates in the Pacific Northwest and the accurate prediction of their behavior in concrete continue to present challenges for the assessment and management of geologic resources to the owners and operators of pits and quarries and to the

  2. Promoting plumbing fixture and fitting replacement: Recommendations and review for state and local water resource authorities

    Energy Technology Data Exchange (ETDEWEB)

    Dunham, C.; Lutz, J.D.; Pickle, S.J.

    1995-06-01

    Lawrence Berkeley National Laboratory (LBNL) has prepared this report to facilitate compliance with the requirements of Section 123 of the Energy Policy Act of 1992 (EPACT). Section 123 requires the Department of Energy to issue recommendations for establishing state and local incentive programs to encourage acceleration of voluntary consumer replacement of existing water closets, urinals, showerheads and faucets with water-saving products meeting EPACT standards. The authors recommend that state and local authorities working together and also with utilities: (A) investigate the cost-effectiveness of voluntary replacement of plumbing fixtures and fittings as an effective component of a water efficiency incentive program; (B) allow utilities to distribute the costs of water saving products by billing at pre-installation rates until devices have been paid for; (C) encourage decreased water usage by establishing rate structures such as increasing block rates or seasonal pricing; (D) add additional incentive to rebate programs by making the rebates untaxable income. (E) require municipalities or utilities to exhaust every reasonable method of water conservation before applying for permits to construct water supply or water treatment systems; (F) require high-efficiency toilets, urinals, showerheads, and faucets in new construction and changing plumbing codes to incorporate different pipe sizing needs; and (G) and mandate installation of meters to correctly measure water consumption. Following the introduction, a general overview of these recommendations is presented. Each recommendation is discussed briefly. After determining the cost-effectiveness of a plumbing replacement program (or plumbing replacement aspect of a larger program) states can encourage replacement of toilets, urinals, showerheads, and faucets in a number of ways. This report lists both legislative and economic measures that can be implemented on the state level that impact local programs.

  3. Non-Markovian Quantum State Diffusion for Temperature-Dependent Linear Spectra of Light Harvesting Aggregates

    CERN Document Server

    Ritschel, Gerhard; Möbius, Sebastian; Strunz, Walter T; Eisfeld, Alexander

    2014-01-01

    Non-Markovian Quantum State Diffusion (NMQSD) has turned out to be an effective method to calculate excitonic properties of aggregates composed of organic chromophores, taking into account the strong coupling of electronic transitions to vibrational modes of the chromophores. In this paper we show how to calculate linear optical spectra at finite temperatures in an efficient way. To this end we map a finite temperature environment to the zero temperature case using the so-called thermofield method. The zero temperature case equations can then be solved efficiently by standard integrators. As an example we calculate absorption and circular dichroism spectra of a linear aggregate. The formalism developed can be applied to calculate arbitrary correlation functions.

  4. Equilibrium excited state and emission spectra of molecular aggregates from the hierarchical equations of motion approach.

    Science.gov (United States)

    Jing, Yuanyuan; Chen, Liping; Bai, Shuming; Shi, Qiang

    2013-01-28

    The hierarchical equations of motion (HEOM) method was applied to calculate the emission spectra of molecular aggregates using the Frenkel exciton model. HEOM equations for the one-exciton excited state were first propagated until equilibration. The reduced density operator and auxiliary density operators (ADOs) were used to characterize the coupled system-bath equilibrium. The dipole-dipole correlation functions were then calculated to obtain the emission spectra of model dimers, and the B850 band of light-harvesting complex II (LH2) in purple bacteria. The effect of static disorder on equilibrium excited state and the emission spectra of LH2 was also explicitly considered. Several approximation schemes, including the high temperature approximation (HTA) of the HEOM, a modified version of the HTA, the stochastic Liouville equation approach, the perturbative time-local and time-nonlocal generalized quantum master equations, were assessed in the calculation of the equilibrium excited state and emission spectra.

  5. Aggregate resource availability in the conterminous United States, including suggestions for addressing shortages, quality, and environmental concerns

    Science.gov (United States)

    Langer, William H.

    2011-01-01

    One-third of America's major roads are in poor or mediocre condition, and over one-quarter of the bridges are either structurally deficient or functionally obsolete. A 70-percent increase in annual aggregate production may be required to upgrade the transportation infrastructure. Natural aggregate is widespread throughout the conterminous United States, but the location of aggregate is determined by geology and is non-negotiable. Natural aggregate is in short supply in the Coastal Plain and Mississippi embayment, Colorado Plateau and Wyoming Basin, glaciated Midwest, High Plains, and the non-glaciated Northern Plains. A variety of techniques have been used to overcome local shortages, such as the use of substitute materials, recycling, and importing high-quality aggregates from more distant locations.

  6. Tillage practices in the conterminous United States, 1989-2004-Datasets Aggregated by Watershed

    Science.gov (United States)

    Baker, Nancy T.

    2011-01-01

    This report documents the methods used to aggregate county-level tillage practices to the 8-digit hydrologic unit (HU) watershed. The original county-level data were collected by the Conservation Technology Information Center (CTIC). The CTIC collects tillage data by conducting surveys about tillage systems for all counties in the United States. Tillage systems include three types of conservation tillage (no-till, ridge-till, and mulch-till), reduced tillage, and intensive tillage. Total planted acreage for each tillage practice for each crop grown is reported to the CTIC. The dataset includes total planted acreage by tillage type for selected crops (corn, cotton, grain sorghum, soybeans, fallow, forage, newly established permanent pasture, spring and fall seeded small grains, and 'other' crops) for 1989-2004. Two tabular datasets, based on the 1992 enhanced and 2001 National Land Cover Data (NLCD), are provided as part of this report and include the land-cover area-weighted interpolation and aggregation of acreage for each tillage practice in each 8-digit HU watershed in the conterminous United States for each crop. Watershed aggregations were done by overlying the 8-digit HU polygons with a raster of county boundaries and a raster of either the enhanced 1992 or the 2001 NLCD for cultivated land to derive a county/land-cover area weighting factor. The weighting factor then was applied to the county-level tillage data for the counties within each 8-digit HU and summed to yield the total acreage of each tillage type within each 8-digit HU watershed.

  7. A general ansatz for constructing quasi-diabatic states in electronically excited aggregated systems

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Wenlan; Köhn, Andreas [Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany); InnovationLab GmbH, Speyerer St. 4, D-69115 Heidelberg (Germany); Lunkenheimer, Bernd [InnovationLab GmbH, Speyerer St. 4, D-69115 Heidelberg (Germany); Institute of Physical Chemistry, University of Mainz, Duesbergweg 10-14, D-55128 Mainz (Germany); Settels, Volker; Engels, Bernd [Institute of Physical and Theoretical Chemistry, University of Würzburg, Emil-Fischer-St. 42, D-97074 Würzburg (Germany); Fink, Reinhold F. [Institute of Physical and Theoretical Chemistry, University of Tübingen, Auf der Morgenstelle 18, D-72076 Tübingen (Germany)

    2015-08-28

    We present a general method for analyzing the character of singly excited states in terms of charge transfer (CT) and locally excited (LE) configurations. The analysis is formulated for configuration interaction singles (CIS) singly excited wave functions of aggregate systems. It also approximately works for the second-order approximate coupled cluster singles and doubles and the second-order algebraic-diagrammatic construction methods [CC2 and ADC(2)]. The analysis method not only generates a weight of each character for an excited state, but also allows to define the related quasi-diabatic states and corresponding coupling matrix elements. In the character analysis approach, we divide the target system into domains and use a modified Pipek-Mezey algorithm to localize the canonical MOs on each domain, respectively. The CIS wavefunction is then transformed into the localized basis, which allows us to partition the wavefunction into LE configurations within domains and CT configuration between pairs of different domains. Quasi-diabatic states are then obtained by mixing excited states subject to the condition of maximizing the weight of one single LE or CT configuration (localization in configuration space). Different aims of such a procedure are discussed, either the construction of pure LE and CT states for analysis purposes (by including a large number of excited states) or the construction of effective models for dynamics calculations (by including a restricted number of excited states). Applications are given to LE/CT mixing in π-stacked systems, charge-recombination matrix elements in a hetero-dimer, and excitonic couplings in multi-chromophoric systems.

  8. Kinetic analysis of protein aggregation monitored by real-time 2D solid-state NMR spectroscopy

    NARCIS (Netherlands)

    Etzkorn, M.; Böckmann, A.; Baldus, M.

    2011-01-01

    It is shown that real-time 2D solid-state NMR can be used to obtain kinetic and structural information about the process of protein aggregation. In addition to the incorporation of kinetic information involving intermediate states, this approach can offer atom-specific resolution for all detectable

  9. Temperature induced structural transitions from native to unfolded aggregated states of tobacco etch virus protease

    Science.gov (United States)

    Zhu, Guo-Fei; Ren, Si-Yan; Xi, Lei; Du, Lin-Fang; Zhu, Xiao-Feng

    2015-02-01

    Tobacco etch virus protease (TEVp) is widely used to remove fusion tags from recombinant proteins because of its high and unique specificity. This work describes the conformational and the thermodynamic properties in the unfolding/refolding process of TEVp3M (three-point mutant: L56V/S135G/S219V) induced by temperature. With temperature increasing from 20 to 100 °C, the CD spectra showed a transition trend from α-helix to β-sheet, and the fluorescence emission, synchronous fluorescence, ANS and RLS spectroscopy consistently revealed that the temperature-induced unfolding process behaved in a three-state manner, for there was a relatively stable intermediate state observed around 50 °C. The reversibility of thermal unfolding of TEVp3M further showed that the transition from the native to the intermediate state was reversible (below 50 °C), however the transition from the intermediate to the unfolded state was irreversible (above 60 °C). Moreover, aggregates were observed above 60 °C as revealed by SDS-PAGE, Thioflavin-T fluorescence and Congo red absorbance.

  10. Non-Markovian Quantum State Diffusion for temperature-dependent linear spectra of light harvesting aggregates

    Science.gov (United States)

    Ritschel, Gerhard; Suess, Daniel; Möbius, Sebastian; Strunz, Walter T.; Eisfeld, Alexander

    2015-01-01

    Non-Markovian Quantum State Diffusion (NMQSD) has turned out to be an efficient method to calculate excitonic properties of aggregates composed of organic chromophores, taking into account the coupling of electronic transitions to vibrational modes of the chromophores. NMQSD is an open quantum system approach that incorporates environmental degrees of freedom (the vibrations in our case) in a stochastic way. We show in this paper that for linear optical spectra (absorption, circular dichroism), no stochastics is needed, even for finite temperatures. Thus, the spectra can be obtained by propagating a single trajectory. To this end, we map a finite temperature environment to the zero temperature case using the so-called thermofield method. The resulting equations can then be solved efficiently by standard integrators.

  11. Meal Replacement: Calming the Hot-State Brain Network of Appetite

    Directory of Open Access Journals (Sweden)

    Brielle ePaolini

    2014-03-01

    Full Text Available There is a growing awareness in the field of neuroscience that the self-regulation of eating behavior is driven by complex networks within the brain. These networks may be vulnerable to hot states which people can move into and out of dynamically throughout the course of a day as a function of changes in affect or visceral cues. The goal of the current study was to identify and determine differences in the Hot-state Brain Network of Appetite (HBN-A that exists after a brief period of food restraint followed either by the consumption of a meal replacement (MR or water. Fourteen overweight/obese adults came to our laboratory on two different occasions. Both times they consumed a controlled breakfast meal and then were restricted from eating for 2.5 hours prior to an MRI scan. On one visit, they consumed a meal replacement (MR liquid meal after this period of food restriction; on the other visit they consumed an equal amount of water. After these manipulations, the participants underwent a resting fMRI scan. Our first study aim employed an exploratory, data-driven approach to identify hubs relevant to the HBN-A. Using data from the water condition, five regions were found to be the hubs or nodes of the HBN-A: insula, anterior cingulated cortex, the superior temporal pole, the amygdala, and the hippocampus. We then demonstrated that the consumption of a liquid MR dampened interconnectivity between the nodes of the HBN-A as compared to water. Importantly and consistent with these network data, the consumption of a MR beverage also lowered state cravings and hunger.

  12. Behavior of the aggregate wind resource in the ISO regions in the United States

    KAUST Repository

    Gunturu, Udaya

    2015-04-01

    The collective behavior of wind farms in seven Independent System Operator (ISO) areas has been studied. The generation duration curves for each ISO show that there is no aggregated power for some fraction of time. Aggregation of wind turbines mitigates intermittency to some extent, but in each ISO there is considerable fraction of time when there is less than 5% capacity. The hourly wind power time series show benefit of aggregation but the high and low wind events are lumped in time, thus indicating that intermittency is synchronized in each region. The timeseries show that there are instances when there is no wind power in most ISOs because of large-scale high pressure systems. An analytical consideration of the collective behavior of aggregated wind turbines shows that the benefit of aggregation saturates beyond a certain number of generating units asymptotically. Also, the benefit of aggregation falls rapidly with temporal correlation between the generating units.

  13. Different states of integrin LFA-1 aggregation are controlled through its association with tetraspanin CD9.

    Science.gov (United States)

    Reyes, Raquel; Monjas, Alicia; Yánez-Mó, María; Cardeñes, Beatriz; Morlino, Giulia; Gilsanz, Alvaro; Machado-Pineda, Yesenia; Lafuente, Esther; Monk, Peter; Sánchez-Madrid, Francisco; Cabañas, Carlos

    2015-10-01

    The tetraspanin CD9 has been shown to interact with different members of the β1 and β3 subfamilies of integrins, regulating through these interactions cell adhesion, migration and signaling. Based on confocal microscopy co-localization and on co-immunoprecipitation results, we report here that CD9 associates with the β2 integrin LFA-1 in different types of leukocytes including T, B and monocytic cells. This association is resistant to stringent solubilization conditions which, together with data from chemical crosslinking, in situ Proximity Ligation Assays and pull-down experiments, suggest a primary/direct type of interaction mediated by the Large Extracellular Loop of the tetraspanin. CD9 exerts inhibitory effects on the adhesive function of LFA-1 and on LFA-1-dependent leukocyte cytotoxic activity. The mechanism responsible for this negative regulation exerted by CD9 on LFA-1 adhesion does not involve changes in the affinity state of this integrin but seems to be related to alterations in its state of aggregation.

  14. 不同再生骨料取代率混凝土柱耐火性能试验研究%Experimental Study on Fire Resistant Performance of Recycled Concrete Columns with Different Replacement Rate of Recycled Aggregate

    Institute of Scientific and Technical Information of China (English)

    曹万林; 边建辉; 董宏英; 张建伟

    2012-01-01

    为研究不同再生骨料取代率混凝土柱的耐火性能,进行了3个足尺再生混凝土柱在竖向荷载和温度场耦合作用下的升温耐火试验.其中,2个试件再生粗骨料取代率为100%,细骨料为天然砂的半再生混凝土柱;1个试件为再生粗、细骨料取代率均为100%的全再生混凝土柱.在试验基础上,比较分析了各试件的截面温度变化、耐火极限、轴向变形、侧向挠度和破坏形态.研究表明:相同轴压比条件下,半再生混凝土柱的耐火极限随着混凝土强度的提高而降低;混凝土强度变化对温度场分布规律影响较小;半再生混凝土柱与全再生混凝土柱相比,混凝土材料性能退化较慢,耐火性能较好.%In order to investigate the fire resistant performance of the recycled concrete columns with different replacement rate of recycled aggregate;three full-sized recycled concrete columns were designed and tested under high temperature and unchanged vertical load. Two of the specimens were made from recycled concrete with 100% of recycled coarse aggregate and 100% of natural fine aggregate;which was called 50% recycled aggregate concrete. The other one was made from recycled concrete with 100% of recycled coarse aggregate and 100% of recycled fine aggregate;which was called 100% recycled aggregate concrete here. Based on the experimental study;several parameters were comparatively analyzed;including the temperature variation at the cross section;fire endurance;vertical displacement;lateral deflection;and failure modes of specimens. Results show that the fire resistant endurance for recycled coarse aggregate concrete column decreases with the concrete strength increases. The concrete compressive strength has little infuence on the temperature field of columns. Compared to the column with 100% recycled aggregate concrete;the column with 50% recycled aggregate concrete has better fire resistant performance and its material property

  15. Innovative Solid State Lighting Replacements for Industrial and Test Facility Locations Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is the replacement of existing test stand and parking lot fixtures with current SSL LED technology. The replacement fixtures will reduce...

  16. 再生骨料替代率对混凝土性能影响的实验分析%Experimental Analysis of the Impact of Recycled Aggregates Replacement Rate on Concrete Properties

    Institute of Scientific and Technical Information of China (English)

    方瑾

    2011-01-01

    Recycled concrete is made from different recycled aggregates replacement rate.Comparing recycled concrete with ordinary concrete from workability,elastic modulus and compressive strength,the article analyzes the impact on the concrete properties from the changes of recycled aggregates substitution rate.The experiment proved that the recycled concrete is equal to ordinary concrete,which is compounded by appropriate recycled aggregates replacement rate.With the emphasis on environmental protection,the development of recycled concrete will be more valuable in application.%用不同的再生骨料替代率,制成再生混凝土。从再生混凝土的和易性、弹性模量和抗压强度等三个方面与普通混凝土进行比较,分析再生骨料替代率的变化对混凝土性能的影响。试验证明,采用适当的再生骨料替代率配制的再生混凝土与普通混凝土基本相当。随着人类对环保的日益重视,再生混凝土产业的发展空间很大,对混凝土的工程应用具有一定的价值意义。

  17. Native myosin from adult rabbit skeletal muscle: isoenzymes and states of aggregation.

    Science.gov (United States)

    Morel, J E; D'hahan, N; Taouil, K; Francin, M; Aguilar, A; Dalbiez, J P; Merah, Z; Grussaute, H; Hilbert, B; Ollagnon, F; Selva, G; Piot, F

    1998-04-21

    The globular heads of skeletal muscle myosin have been shown to exist as isoenzymes S1 (A1) and S1 (A2), and there are also isoforms of the heavy chains. Using capillary electrophoresis, we found two dominant isoenzymes of the whole native myosin molecule, in agreement with what has previously been found by various techniques for native and nondenatured myosin from adult rabbits. Findings about possible states of aggregation of myosin and its heads are contradictory. By analytical ultracentrifugation, we confirmed the existence of a tail-tail dimer. By laser light scattering, we found a head-head dimer in the presence of MgATP. Capillary electrophoresis coupled with analytical ultracentrifugation and laser light scattering led us to refine these results. We found tail-tail dimers in a conventional buffer. We found tail-tail and head-head dimers in the presence of 0.5 mM MgATP and pure head-head dimers in the presence of 6 mM MgATP. All the dimers were homodimers. Naming the dominant isoenzymes of myosin a and b, we observed tail-tail dimers with isoenzyme a (TaTa) and with isoenzyme b (TbTb) and also head-head dimers with isoenzyme a (HaHa) and with isoenzyme b (HbHb).

  18. Alkali-silica reaction of aggregates for concrete pavements in Chihuahua’s State, Mexico

    Directory of Open Access Journals (Sweden)

    Olague, C.

    2002-12-01

    Full Text Available The concrete of pavements must resist the climatic conditions, heavy traffic, chemical agents or any other type of aggressive agent. A methodology for characterizing materials that would influence concrete durability was developed considering chemical and physical factors. This methodology allows the consideration of several factors like physiography, geology, and climate, among others that would be of great importance to prevent future durability problems of pavements. This methodology takes into account several tests and this paper presents the results of potential reactivity aggregates of the State of Chihuahua. The tests for evaluating the reactive siliceous aggregate and the potential alkali-silica reactivity were performed according to the: petrographic examination (ASTM C 295 and standard quick chemical test (ASTM C 289. 38% of the tested sites resulted innocuous, 48% potentially reactive and 13% reactive. It is discussed the benefit of applying a conscious methodology in order to obtain the best results with a representative quantity of tests.

    El hormigón de los pavimentos debe ser resistente a las condiciones climáticas, tránsito pesado, agentes químicos o cualquier otro tipo de agente agresivo. Se desarrolló una metodología para caracterización de materiales considerando factores físicos y químicos que influyen en la durabilidad del hormigón. Esta metodología se basa en la consideración de varios factores como: fisiografía, geología y clima, entre otros, que podrían ser de gran importancia para prevenir futuros problemas de durabilidad en pavimentos de hormigón. La metodología en cuestión considera varias pruebas, en este artículo se presentan los resultados de la reactividad potencial de los áridos del Estado de Chihuahua. Las pruebas para evaluar la reactividad de áridos silíceos y la reactividad potencial álcali-sílice fueron ejecutadas de acuerdo a: examen petrográfico (ASTM C 295 y la prueba qu

  19. Directed Replacement

    CERN Document Server

    Karttunen, L

    1996-01-01

    This paper introduces to the finite-state calculus a family of directed replace operators. In contrast to the simple replace expression, UPPER -> LOWER, defined in Karttunen (ACL-95), the new directed version, UPPER @-> LOWER, yields an unambiguous transducer if the lower language consists of a single string. It transduces the input string from left to right, making only the longest possible replacement at each point. A new type of replacement expression, UPPER @-> PREFIX ... SUFFIX, yields a transducer that inserts text around strings that are instances of UPPER. The symbol ... denotes the matching part of the input which itself remains unchanged. PREFIX and SUFFIX are regular expressions describing the insertions. Expressions of the type UPPER @-> PREFIX ... SUFFIX may be used to compose a deterministic parser for a ``local grammar'' in the sense of Gross (1989). Other useful applications of directed replacement include tokenization and filtering of text streams.

  20. Wear characteristics of Wright State University total ankle -replacement under shear and torsion loads

    OpenAIRE

    Gundapaneni, Dinesh; Goswami, Tarun

    2014-01-01

    Introduction: Total ankle replacement (TAR) involves replacement of the damaged bone with prosthetic components and is usually performed in patients suffering with arthritis to relieve pain and maintain motion. There are several different factors that contribute to failure of TARs but aseptic loosening is the primary method of failure in total ankle replacements. Because of its superior mechanical properties UHMWPE is used as a liner material in TARs. Wear generated from the liner due to high...

  1. Protein folding, unfolding and aggregation. Pressure induced intermediate states on the refolding pathway of horseradish peroxidase

    Science.gov (United States)

    Smeller, László; Fidy, Judit; Heremans, Karel

    2004-04-01

    We studied the refolding and aggregation of pressure unfolded proteins. Horseradish peroxidase was found to be very stable and no partially folded intermediates were populated during the refolding. However, the removal of the haem group or the Ca2+ ions or reduction of the disulfide bridge destabilized the protein, resulting in a significant amount of aggregation prone intermediate conformation. Substitution of the haem for fluorescent porphyrin however did not influence the refolding of the protein.

  2. Trends in Testosterone Replacement Therapy Use from 2003 to 2013 among Reproductive-Age Men in the United States.

    Science.gov (United States)

    Rao, Pravin Kumar; Boulet, Sheree L; Mehta, Akanksha; Hotaling, James; Eisenberg, Michael L; Honig, Stanton C; Warner, Lee; Kissin, Dmitry M; Nangia, Ajay K; Ross, Lawrence S

    2017-04-01

    Although testosterone replacement therapy use in the United States has increased dramatically in the last decade, to our knowledge trends in testosterone replacement therapy use among reproductive-age men have not been investigated. We assessed changes in testosterone replacement therapy use and practice patterns among 18 to 45-year-old American men from 2003 to 2013 and compared them to older men. This is a retrospective, cross-sectional analysis of men 18 to 45 and 56 to 64 years old who were enrolled in the Truven Health MarketScan® Commercial Claims Databases throughout each given calendar year from 2003 to 2013, including 5,094,868 men in 2013. Trends in the yearly rates of testosterone replacement therapy use were calculated using Poisson regression. Among testosterone replacement therapy users, the Cochran-Armitage test was used to assess temporal trends in age, formulation type, semen analysis and serum testosterone level testing during the 12 months preceding the documented use of testosterone replacement therapy. Between 2003 and 2013, there was a fourfold increase in the rate of testosterone use among 18 to 45-year-old men from 29.2/10,000 person-years to 118.1/10,000 person-years (p testosterone replacement therapy users, topical gel formulations were initially most used. Injection use then doubled between 2009 and 2012 (23.5% and 46.2%, respectively) and surpassed topical gel use in 2013. In men 56 to 64 years old there was a statistically significant threefold increase in testosterone replacement therapy use (p testosterone replacement therapy use increased fourfold in men 18 to 45 years old compared to threefold in older men. This younger age group should be a focus for future studies due to effects on fertility and unknown long-term sequelae. Copyright © 2017 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  3. Both compressive test and drying shrinkage test on recycled aggregate concrete with different fine recycled aggregate replacement ratio%不同再生细骨料取代率混凝土的抗压及干燥收缩试验研究

    Institute of Scientific and Technical Information of China (English)

    郝彤; 赵文兰

    2011-01-01

    对不同再乍细骨料替代率混凝土的抗压性能和干燥收缩性能进行研究.结果表明,随着再生细骨料替代率的提高,再生混凝土呈脆性趋势发展,但当采用基于自由水灰比的配合比设计方法和二次搅拌工艺时,再生细骨料混凝土的强度基本与普通混凝土相近.再生混凝土的收缩机理与普通混凝土基本相同,再生细骨料混凝土的收缩值随龄期增长而逐渐增大;再生混凝土的干燥收缩率大于普通混凝土;随着再生细骨料替代率的增加,再生混凝土收缩率随之增大.%Both compressive test and drying shrinkage test on recycled aggregate concrete with different fine recycled aggregate replacement ratio were studied. The reaults show that with the replacement ratio increase,recycled concreie are becoming more and more brittle:with the mixing proportion design of free W/C and the secondary mixing process,compressive intensity of recycled cancrete iB nearly comparable with those of normal concrete with similar composition.The shrinkage theory of the recycled concrete is the same as natural aggregate concrete,with the increase of the curing ages,the shrinkage of the recycled concrete increases;the shrinkage of the recycled concrete is higher than that of natural aggregate concrete;with the ingrease of the replacement rate,the shrinkage of the recycled concrete increases.

  4. Sources of information influencing the state-of-the-science gap in hormone replacement therapy usage.

    Science.gov (United States)

    Chew, Fiona; Wu, Xianwei

    2017-01-01

    Medical reviews and research comprise a key information source for news media stories on medical therapies and innovations as well as for physicians in updating their practice. The present study examined medical review journal articles, physician surveys and news media coverage of hormone replacement therapy (HT) to assess the relationship between the three information sources and whether/if they contributed to a state-of-the-science gap (a condition when the evaluation of a medical condition or therapy ascertained by the highest standards of investigation is incongruent with the science-in-practice such as physician recommendations and patient actions). We content-analyzed 177 randomly sampled HT medical reviews between 2002 and 2014, and HT news valence in three major TV networks, newspapers and magazines/internet sites in 2002-2003, 2008-2009 and 2012-14. The focus in both analyses was whether HT benefits outweighed risks, risks outweighed benefits or both risks and benefits were presented. We also qualitatively content-analyzed all 19 surveys of US physicians' HT recommendations from 2002 to 2009, and 2012 to 2014. Medical reviews yielded a mixed picture about HT (40.1% benefits, 26.0% risks, and 33.9% both benefits and risks). While a majority of physician surveys were pro-HT 10/19), eight showed varied attitudes and one was negative. Newspaper and television coverage reflected a pro and con balance while magazine stories were more positive in the later reporting period. Medical journal review articles, physicians, and media reports all provide varying view points towards hormone therapy use thus leading to limited knowledge about the actual risks and benefits of HT among peri- and menopausal women and a state-of-the-science gap.

  5. Sources of information influencing the state-of-the-science gap in hormone replacement therapy usage

    Science.gov (United States)

    Wu, Xianwei

    2017-01-01

    Objective Medical reviews and research comprise a key information source for news media stories on medical therapies and innovations as well as for physicians in updating their practice. The present study examined medical review journal articles, physician surveys and news media coverage of hormone replacement therapy (HT) to assess the relationship between the three information sources and whether/if they contributed to a state-of-the-science gap (a condition when the evaluation of a medical condition or therapy ascertained by the highest standards of investigation is incongruent with the science-in-practice such as physician recommendations and patient actions). Methods We content-analyzed 177 randomly sampled HT medical reviews between 2002 and 2014, and HT news valence in three major TV networks, newspapers and magazines/internet sites in 2002–2003, 2008–2009 and 2012–14. The focus in both analyses was whether HT benefits outweighed risks, risks outweighed benefits or both risks and benefits were presented. We also qualitatively content-analyzed all 19 surveys of US physicians’ HT recommendations from 2002 to 2009, and 2012 to 2014. Results Medical reviews yielded a mixed picture about HT (40.1% benefits, 26.0% risks, and 33.9% both benefits and risks). While a majority of physician surveys were pro-HT 10/19), eight showed varied attitudes and one was negative. Newspaper and television coverage reflected a pro and con balance while magazine stories were more positive in the later reporting period. Conclusion Medical journal review articles, physicians, and media reports all provide varying view points towards hormone therapy use thus leading to limited knowledge about the actual risks and benefits of HT among peri- and menopausal women and a state-of-the-science gap. PMID:28158240

  6. Communal spaces: aggregation and integration in the Mogollon Region of the United States Southwest

    Energy Technology Data Exchange (ETDEWEB)

    Nisengard, Jennifer E.

    2006-12-01

    Aggregation and integration are processes that occur in human societies throughout the globe. An informative example of population aggregation and social integration can be observed in the North American desert borderlands from A.D. 250 to 1450 in the area known as the Mogollon region. In fact, Mogollon communities oscillated from smaller social groups into larger ones and dispersed into smaller groups only to form larger ones again. For this reason, examining the groups of people living in the Mogollon region provides a magnified view of social change over a substantial period. Understanding patterns of aggregation and integration provides researchers with the promise for research into the nature of these phenomena. In general, the Mogollon region is characterized by limited water supplies and low average annual precipitation. However, pockets of the Mogollon area, including the Mimbres valley and the Gila River valley, represent oases, where permanent rivers and their associated tributaries allowed for the pursuit of agricultural endeavors and access to a wide variety of wild plant and animal resources. The areas with these kinds of potential became population centers for previously dispersed groups of people living in the region. These people exploited natural resources and practiced agriculture in areas surrounding their communities. Over time, more organized aggregated and socially integrated communities were established throughout the region. Using ancient Mogollon communal architecture, commonly called kivas, this study examines issues of, and evidence for, population aggregation and social integration.

  7. Bio-aggregates based building materials state-of-the-art report of the RILEM Technical Committee 236-BBM

    CERN Document Server

    Collet, Florence

    2017-01-01

    The work of the RILEM Technical Committee (TC -236 BBM) was dedicated to the study of construction materials made from plant particles. It considered the question whether building materials containing as main raw material recyclable and easily available plant particles are renewable. This book includes a state-of-the-art report and an appendix. The state-of-the-art report relates to the description of vegetal aggregates. Then, hygrothermal properties, fire resistance, durability and finally the impact of the variability of the method of production of bio-based concrete are assessed. The appendix is a TC report which presents the experience of a working group. The goal was to define testing methods for the measurement of water absorption, bulk density, particle size distribution, and thermal conductivity of bio aggregates. The work is based on a first round robin test of the TC-BBM where the protocols in use by the different laboratories (labs) are compared. .

  8. OMERACT/OARSI initiative to define states of severity and indication for joint replacement in hip and knee osteoarthritis

    DEFF Research Database (Denmark)

    Gossec, Laure; Hawker, Gillian; Davis, Aileen M

    2007-01-01

    OBJECTIVE: Time to theoretical indication of joint replacement surgery has been proposed as a primary outcome for potential structure-modifying interventions for osteoarthritis (OA). The objectives of this OMERACT/OARSI Working Group were to identify pain, physical function, and structure states ...

  9. Some Issues on Gender and Renal Replacement Therapy in Kano State, Nigeria: Implications for Development

    Directory of Open Access Journals (Sweden)

    Nuratu Muhammad

    2013-07-01

    Full Text Available The study examined some issues on Gender and renal replacement therapy (RRT in Kano state. Stratified sampling technique was used to select 46 males and 26 females from Aminu Kano teaching hospital (AKTH and Abdullah Wase or Nassarawa specialist hospital. Before embarking on data collection, ethical approval was sought and given by the ministry of health Kano state for Abdullah Wase hospital and the management of AKTH hospital. Data was derived primarily from the questionnaire administered to the selected samples, in addition hospital based records of patients were obtained from the dialysis unit of the two hospitals. The results of the study showed that both male and female patients delayed in RRT. However majority of the males and females delayed due to inadequate information(19% and(18% and lack of money(y25% and (18%for the male and female patients resulting from the low socio economic status of most of them as indicated in the tables on education and income of the respondents, Other factors that caused infrequent RRT included the long term nature of treatment (12% and (23%, tried out alternative treatment (19% and (18%males and females respectively. Some of the socio economic and psychological costs of RRT were found to include cut in social spending( 22% males and(15% females, increased expenditure on health (17% and( 19% ,frequent illness (22% and (31%, loss of job (4%males only ,decrease in number of hours put to work (30% and( 31% matrimonial problems ((4% and another ( 4%for the males and females respectively Based on the findings of this research it is recommended that government ad stakeholders need to redefine their priorities and place health matters as a top priority in all state matters as the saying goes a healthy nation is a wealthy nation. Normal 0 false false false EN-US X-NONE AR-SA /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso

  10. A novel nonanuclear CuII carboxylate-bridged cluster aggregate with an S= 7/2 ground spin state.

    Science.gov (United States)

    Murugesu, Muralee; King, Philippa; Clérac, Rodolphe; Anson, Christopher E; Powell, Annie K

    2004-03-21

    The Cu(II) aggregate in [Cu(9)(cpida)(6)(MeOH)(6)].6(MeOH)[H(3)cpida = 2-(carboxyphenyl)iminodiacetic acid] is made up of two weakly ferromagnetically coupled carboxylate-bridged Cu(4) units that are antiferromagnetically linked through a central Cu(II) to give a Cu(9) core with an S= 7/2 spin ground state.

  11. Classification of carbon materials for developing structure-properties relationships based on the aggregate state of the precursors

    Institute of Scientific and Technical Information of China (English)

    Oleksiy V. Khavryuchenko; Volodymyr D.Khavryuchenko

    2014-01-01

    Modern carbon science lacks an efficient structure-related classi-fication of materials. We present an approach based on dividing carbon materials by the aggregate state of the precursor. The common features in the structure of carbon particles that allow putting them into a group are discussed, with particular attention to the potential energy stored in the carbon structure from differ-ent rates of relaxation during the synthesis and prearrangement of structural motifs due to the effect of the precursor structure.

  12. Frozen-state storage stability of a monoclonal antibody: aggregation is impacted by freezing rate and solute distribution.

    Science.gov (United States)

    Miller, Maria A; Rodrigues, Miguel A; Glass, Matthew A; Singh, Satish K; Johnston, Keith P; Maynard, Jennifer A

    2013-04-01

    Freezing of protein solutions perturbs protein conformation, potentially leading to aggregate formation during long-term storage in the frozen state. Macroscopic protein concentration profiles in small cylindrical vessels were determined for a monoclonal antibody frozen in a trehalose-based formulation for various freezing protocols. Slow cooling rates led to concentration differences between outer edges of the tank and the center, up to twice the initial concentration. Fast cooling rates resulted in much smaller differences in protein distribution, likely due to the formation of dendritic ice, which traps solutes in micropockets, limiting their transport by convection and diffusion. Analysis of protein stability after more than 6 months storage at either -10°C or -20°C [above glass transition temperature (T'g )] or -80°C (below T'g ) revealed that aggregation correlated with the cooling rate. Slow-cooled vessels stored above T'g exhibited increased aggregation with time. In contrast, fast-cooled vessels and those stored below T'g showed small to no increase in aggregation at any position. Rapid entrapment of protein in a solute matrix by fast freezing results in improved stability even when stored above T'g . © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 102:1194-1208, 2013.

  13. Impact of the economic downturn on total joint replacement demand in the United States: updated projections to 2021.

    Science.gov (United States)

    Kurtz, Steven M; Ong, Kevin L; Lau, Edmund; Bozic, Kevin J

    2014-04-16

    Few studies have explored the role of the National Health Expenditure and macroeconomics on the utilization of total joint replacement. The economic downturn has raised questions about the sustainability of growth for total joint replacement in the future. Previous projections of total joint replacement demand in the United States were based on data up to 2003 using a statistical methodology that neglected macroeconomic factors, such as the National Health Expenditure. Data from the Nationwide Inpatient Sample (1993 to 2010) were used with United States Census and National Health Expenditure data to quantify historical trends in total joint replacement rates, including the two economic downturns in the 2000s. Primary and revision hip and knee arthroplasty were identified using codes from the International Classification of Diseases, Ninth Revision, Clinical Modification. Projections in total joint replacement were estimated using a regression model incorporating the growth in population and rate of arthroplasties from 1993 to 2010 as a function of age, sex, race, and census region using the National Health Expenditure as the independent variable. The regression model was used in conjunction with government projections of National Health Expenditure from 2011 to 2021 to estimate future arthroplasty rates in subpopulations of the United States and to derive national estimates. The growth trend for the incidence of joint arthroplasty, for the overall United States population as well as for the United States workforce, was insensitive to economic downturns. From 2009 to 2010, the total number of procedures increased by 6.0% for primary total hip arthroplasty, 6.1% for primary total knee arthroplasty, 10.8% for revision total hip arthroplasty, and 13.5% for revision total knee arthroplasty. The National Health Expenditure model projections for primary hip replacement in 2020 were higher than a previously projected model, whereas the current model estimates for total

  14. Exchange narrowing in circular and cylindrical molecular aggregates : degenerate versus nondegenerate states

    NARCIS (Netherlands)

    Didraga, Cătălin; Knoester, Jasper

    2002-01-01

    We study the optical absorption line shape of circular and cylindrical molecular aggregates with static Gaussian diagonal and off-diagonal disorder. We focus on the weak-disorder situation and analyze the effect of exchange narrowing of the disorder due to exciton delocalization. In particular, we s

  15. Effect of alanine replacement of l17 and f19 on the aggregation and neurotoxicity of arctic-type aβ40.

    Directory of Open Access Journals (Sweden)

    Yi-Ru Chen

    Full Text Available Alzheimer's disease is the most common form of neurodegenerative disease. Beta-amyloid peptides (Aβ are responsible for neuronal death both in vitro and in vivo. Previously, L17 and F19 residues were identified as playing key roles in the stabilization of the Aβ40 conformation and in the reduction of its neurotoxicity. In this study, the effects of L17A/F19A mutations on the neurotoxicity of Aβ genetic mutant Arctic-type Aβ40(E22G were tested. The results showed that compared to Aβ40(E22G, Aβ40(L17A/F19A/E22G reduced the rate of conformation conversion, aggregation, and cytotoxicity, suggesting that L17 and F19 are critical residues responsible for conformational changes which may trigger the neurotoxic cascade of Aβ. Aβ40(L17A/F19A/E22G also had decreased damage due to reactive oxygen species. The results are consistent with the discordant helix hypothesis, and confirm that residues 17-25 are in the discordant helix region. Compared to Aβ40(L17A/F19A, reduction in aggregation of Aβ40(L17A/F19A/E22G was less significantly decreased. This observation provides an explanation based on the discordant helix hypothesis that the mutation of E22 to G22 of Aβ40(E22G alters the propensity of the discordant helix. Arctic-type Aβ40(E22G aggregates more severely than wild-type Aβ40, with a consequential increase in toxicity.

  16. Effect of aggregation, morphology and mixing state on optical properties of bare and internally mixed Black Carbon particles

    Science.gov (United States)

    Scarnato, Barbara; China, Swarup; Mazzoleni, Claudio

    2014-05-01

    Black carbon (BC) is a small, dark particle that warms Earth's climate. BC is a distinct type of carbonaceous aerosol particle, product of combustion of fossil and biomass fuels. Upon emission into the atmosphere, BC internally mixes with other aerosol compounds. According to recent studies, internal mixing of BC with other aerosol materials in the atmosphere alters its aggregate shape, absorption of solar radiation, and radiative forcing. These mixing state effects are not yet fully understood. Laboratory and field studies have identified a strong variability in the observed absorption efficiencies of internally mixed BC. Additionally, there is a discrepancy between modeled and measured values using traditional modeling approaches. This talk will investigate the central role of parameterization of light interaction by BC particles in the assessment of its radiative forcing and present a sensitivity study of the effect of aggregation, morphology and mixing state on optical properties of bare and internally mixed BC with mineral dust, ammonium sulfate, sodium chloride and others. Optical properties of the different mixtures, sampled both in field campaigns and laboratory environment, are computed using Discrete Dipole Approximation model in accordance with BC aggregation, morphology and mixing observed at microscopes. The results of this work are relevant for several applications in atmospheric science, including but not limited to radiative transfer calculations, regional and global climate modeling and, the interpretation of remote sensing measurements.

  17. Intra and inter-molecular interactions dictate the aggregation state of irinotecan co-encapsulated with floxuridine inside liposomes

    DEFF Research Database (Denmark)

    Dicko, A.; Frazier, A.A.; Liboiron, B.D.

    2008-01-01

    PURPOSE: The inter/intramolecular interactions between drugs (floxuridine, irinotecan) and excipients (copper gluconate, triethanolamine) in the dual-drug liposomal formulation CPX-1 were elucidated in order to identify the physicochemical properties that allow coordinated release of irinotecan...... the aggregation state of the drugs within the liposomes. RESULTS: Coordinated release of the drugs from liposomes was disrupted by removing copper gluconate. Approximately 45% of the total irinotecan was detectable in the copper-containing CPX-1 formulation by NMR, which decreased to 19% without copper present...... in the liposomal interior. Formation of higher order, NMR-silent aggregates was associated with slower and uncoordinated irinotecan release relative to floxuridine and loss of the synergistic drug/drug ratio. Solution spectroscopy and calorimetry revealed that while all formulation components were required...

  18. Familial aggregation of blood pressure with respect to anthropometric variables in a business community of Punjab, a north Indian state.

    Science.gov (United States)

    Badaruddoza; Sawhney, Rashveen

    2009-12-01

    This study aimed to examine the familial aggregation of blood pressure with respect to anthropometric variables in an upper-middle class business community in Punjab, a northern state of India. The results were evaluated in a sample of 75 families, constituting 305 individual from three generations such as offspring, parental and grandparental. The data were analyzed through familial correlations, multiple regressions, percent of variance and univariate analysis. The data indicate a strong familial aggregation of blood pressure in this population especially in offspring generations and show that such a familial influence on blood pressure can be detected from the different anthropometric variables, genetic factors, shared household environment and age. These effects were strong in SBP and moderate in DBP. SBP and DBP have showed higher genetic correlation with many anthropometric characters in offspring generation as compared to other generations. These correlations are negligible in male grandparental generation. The results suggest that almost all measured variables are significant multivariate correlates with blood pressure.

  19. Replacing penalties

    Directory of Open Access Journals (Sweden)

    Vitaly Stepashin

    2017-01-01

    Full Text Available УДК 343.24The subject. The article deals with the problem of the use of "substitute" penalties.The purpose of the article is to identify criminal and legal criteria for: selecting the replacement punishment; proportionality replacement leave punishment to others (the formalization of replacement; actually increasing the punishment (worsening of legal situation of the convicted.Methodology.The author uses the method of analysis and synthesis, formal legal method.Results. Replacing the punishment more severe as a result of malicious evasion from serving accused designated penalty requires the optimization of the following areas: 1 the selection of a substitute punishment; 2 replacement of proportionality is serving a sentence other (formalization of replacement; 3 ensuring the actual toughening penalties (deterioration of the legal status of the convict. It is important that the first two requirements pro-vide savings of repression in the implementation of the replacement of one form of punishment to others.Replacement of punishment on their own do not have any specifics. However, it is necessary to compare them with the contents of the punishment, which the convict from serving maliciously evaded. First, substitute the punishment should assume a more significant range of restrictions and deprivation of certain rights of the convict. Second, the perfor-mance characteristics of order substitute the punishment should assume guarantee imple-mentation of the new measures.With regard to replacing all forms of punishment are set significant limitations in the application that, in some cases, eliminates the possibility of replacement of the sentence, from serving where there has been willful evasion, a stricter measure of state coercion. It is important in the context of the topic and the possibility of a sentence of imprisonment as a substitute punishment in cases where the original purpose of the strict measures excluded. It is noteworthy that the

  20. 41 CFR 102-74.570 - Are State and local governments required to fund the cost of installing, repairing, and replacing...

    Science.gov (United States)

    2010-07-01

    ... Replacing Sidewalks § 102-74.570 Are State and local governments required to fund the cost of installing... 41 Public Contracts and Property Management 3 2010-07-01 2010-07-01 false Are State and local governments required to fund the cost of installing, repairing, and replacing sidewalks? 102-74.570...

  1. Feature activated molecular dynamics: an efficient approach for atomistic simulation of solid-state aggregation phenomena.

    Science.gov (United States)

    Prasad, Manish; Sinno, Talid

    2004-11-01

    An efficient approach is presented for performing efficient molecular dynamics simulations of solute aggregation in crystalline solids. The method dynamically divides the total simulation space into "active" regions centered about each minority species, in which regular molecular dynamics is performed. The number, size, and shape of these regions is updated periodically based on the distribution of solute atoms within the overall simulation cell. The remainder of the system is essentially static except for periodic rescaling of the entire simulation cell in order to balance the pressure between the isolated molecular dynamics regions. The method is shown to be accurate and robust for the Environment-Dependant Interatomic Potential (EDIP) for silicon and an Embedded Atom Method potential (EAM) for copper. Several tests are performed beginning with the diffusion of a single vacancy all the way to large-scale simulations of vacancy clustering. In both material systems, the predicted evolutions agree closely with the results of standard molecular dynamics simulations. Computationally, the method is demonstrated to scale almost linearly with the concentration of solute atoms, but is essentially independent of the total system size. This scaling behavior allows for the full dynamical simulation of aggregation under conditions that are more experimentally realizable than would be possible with standard molecular dynamics.

  2. Changes of conformation and aggregation state induced by binding of lanthanide ions to insulin

    Institute of Scientific and Technical Information of China (English)

    程驿; 李荣昌; 王夔

    2002-01-01

    To clarify the mechanism of lanthanide ions (Ln3+) on the across-membrane transport of insulin and subsequent reducing blood glucose, the interactions of Ln3+with Zn-insulin and Zn-free insulin are investigated by spectroscopic methods. The results reveal that the binding of Ln3+ to insulin can induce its structure changes from secondary to quaternary structure, depending on the Ln3+ concentration. In the lower concentration, it triggers the conformational changes of insulin monomer in the binding region with insulin receptor (B(24-30)). It would affect insulin-insulin receptor interaction. Moreover, Ln3+ binding promotes the assembly of insulin monomer from dimer to polymer. The potency of Ln3+ in inducing insulin’s aggregation is stronger than that of Zn2+. Furthermore, the aggregation can be reversed partly by EDTA-treatment, indicating that it is not due to denaturation. Similar to Zn2+ effect, Ln3+ can stabilize insulin hexamer in a certain range of concentration, but is stronger than the former.

  3. Changes of conformation and aggregation state induced by binding of lanthanide ions to insulin

    Institute of Scientific and Technical Information of China (English)

    程驿; 李荣昌; 王夔

    2002-01-01

    To clarify the mechanism of lanthanide ions (Ln3+) on the across-membrane transport of insulin and subsequent reducing blood glucose, the interactions of Ln3+ with Zn-insulin and Zn-free insulin are investigated by spectroscopic methods. The results reveal that the binding of Ln3+ to insulin can induce its structure changes from secondary to quaternary structure, depending on the Ln3+ concentration. In the lower concentration, it triggers the conformational changes of insulin monomer in the binding region with insulin receptor (B(24-30)). It would affect insulin-insulin receptor interaction. Moreover, Ln3+ binding promotes the assembly of insulin monomer from dimer to polymer. The potency of Ln3+ in inducing insulin's aggregation is stronger than that of Zn2+. Furthermore, the aggregation can be reversed partly by EDTA-treatment, indicating that it is not due to denaturation. Similar to Zn2+ effect, Ln3+ can stabilize insulin hexamer in a certain range of concentration, but is stronger than the former.

  4. Enhanced solid-state order and field-effect hole mobility through control of nanoscale polymer aggregation

    KAUST Repository

    Chen, Mark S.

    2013-12-26

    Efficient charge carrier transport in organic field-effect transistors (OFETs) often requires thin films that display long-range order and close π-π packing that is oriented in-plane with the substrate. Although some polymers have achieved high field-effect mobility with such solid-state properties, there are currently few general strategies for controlling the orientation of π-stacking within polymer films. In order to probe structural effects on polymer-packing alignment, furan-containing diketopyrrolopyrrole (DPP) polymers with similar optoelectronic properties were synthesized with either linear hexadecyl or branched 2-butyloctyl side chains. Differences in polymer solubility were observed and attributed to variation in side-chain shape and polymer backbone curvature. Averaged field-effect hole mobilities of the polymers range from 0.19 to 1.82 cm2/V·s, where PDPP3F-C16 is the least soluble polymer and provides the highest maximum mobility of 2.25 cm2/V·s. Analysis of the films by AFM and GIXD reveal that less soluble polymers with linear side chains exhibit larger crystalline domains, pack considerably more closely, and align with a greater preference for in-plane π-π packing. Characterization of the polymer solutions prior to spin-coating shows a correlation between early onset nanoscale aggregation and the formation of films with highly oriented in-plane π-stacking. This effect is further observed when nonsolvent is added to PDPP3F-BO solutions to induce aggregation, which results in films with increased nanostructural order, in-plane π-π orientation, and field-effect hole mobilities. Since nearly all π-conjugated materials may be coaxed to aggregate, this strategy for enhancing solid-state properties and OFET performance has applicability to a wide variety of organic electronic materials. © 2013 American Chemical Society.

  5. Interactions of Pluronic nanocarriers with 2D and 3D cell cultures: Effects of PEO block length and aggregation state.

    Science.gov (United States)

    Arranja, Alexandra; Denkova, Antonia G; Morawska, Karolina; Waton, Gilles; van Vlierberghe, Sandra; Dubruel, Peter; Schosseler, François; Mendes, Eduardo

    2016-02-28

    This work reveals how the physicochemical properties of Pluronic block copolymers influence significantly their interactions with cancer cells, whether in monolayer or spheroid cultures, and how different clinical applications can be foreseen. Two-dimensional (2D) and three-dimensional (3D) cell culture models were used to investigate the interactions of Pluronic carriers with different PEO block length and aggregation state (unimers versus cross-linked micelles) in HeLa and U87 cancer cells. Stabilized micelles of Pluronic P94 or F127 were obtained by polymerization of a crosslinking agent in the micelles hydrophobic core. Nanocarriers were functionalized with a fluorescent probe for visualization, and with a chelator for radiolabeling with Indium-111 and gamma-quantification. The 2D cell models revealed that the internalization pathways and ultimate cellular localization of the Pluronic nanocarriers depended largely on both the PEO block size and aggregation state of the copolymers. The smaller P94 unimers with an average radius of 2.1nm and the shortest PEO block mass (1100gmol(-1)) displayed the highest cellular uptake and retention. 3D tumor spheroids were used to assess the penetration capacity and toxicity potential of the nanocarriers. Results showed that cross-linked F127 micelles were more efficiently delivered across the tumor spheroids, and the penetration depth depends mostly on the transcellular transport of the carriers. The Pluronic P94-based carriers with the shortest PEO block length induced spheroid toxicity, which was significantly influenced by the spheroid cellular type.

  6. SPECT/CT Imaging of Pluronic Nanocarriers with Varying Poly(ethylene oxide) Block Length and Aggregation State.

    Science.gov (United States)

    Arranja, Alexandra; Ivashchenko, Oleksandra; Denkova, Antonia G; Morawska, Karolina; van Vlierberghe, Sandra; Dubruel, Peter; Waton, Gilles; Beekman, Freek J; Schosseler, François; Mendes, Eduardo

    2016-03-07

    Optimal biodistribution and prolonged circulation of nanocarriers improve diagnostic and therapeutic effects of enhanced permeability and retention-based nanomedicines. Despite extensive use of Pluronics in polymer-based pharmaceuticals, the influence of different poly(ethylene oxide) (PEO) block length and aggregation state on the biodistribution of the carriers is rather unexplored. In this work, we studied these effects by evaluating the biodistribution of Pluronic unimers and cross-linked micelles with different PEO block size. In vivo biodistribution of (111)In-radiolabeled Pluronic nanocarriers was investigated in healthy mice using single photon emission computed tomography. All carriers show fast uptake in the organs from the reticuloendothelial system followed by a steady elimination through the hepatobiliary tract and renal filtration. The PEO block length affects the initial renal clearance of the compounds and the overall liver uptake. The aggregation state influences the long-term accumulation of the nanocarriers in the liver. We showed that the circulation time and elimination pathways can be tuned by varying the physicochemical properties of Pluronic copolymers. Our results can be beneficial for the design of future Pluronic-based nanomedicines.

  7. Potential nutritional and economic effects of replacing juice with fruit in the diets of children in the United States.

    Science.gov (United States)

    Monsivais, Pablo; Rehm, Colin D

    2012-05-01

    To estimate the nutritional and economic effects of substituting whole fruit for juice in the diets of children in the United States. Secondary analyses using the 2001-2004 National Health and Nutrition Examination Survey and a national food prices database. Energy intakes, nutrient intakes, and diet costs were estimated before and after fruit juices were completely replaced with fruit in 3 models that emphasized fruits that were fresh, inexpensive, and widely consumed and in a fourth model that partially replaced juice with fruit, capping juice at recommended levels. A nationwide, representative sample of children in the United States. A total of 7023 children aged 3 to 18 years. Systematic complete or partial replacement of juice with fruit. Difference in energy intakes, nutrient intakes, and diet costs between observed and modeled diets. For children who consumed juice, replacement of all juice servings with fresh, whole fruit led to a projected reduction in dietary energy of 233 kJ/d (-2.6% difference [95% CI, -5.1% to -0.1%]), an increase in fiber of 4.3 g/d (31.1% difference [95% CI, 26.4%-35.9%]), and an increase in diet cost of $0.54/d (13.3% difference [95% CI, 8.8%-17.8%]). Substitution of juice with fresh fruit has the potential to reduce energy intake and improve the adequacy of fiber intake in children's diets. This would likely increase costs for schools, childcare providers, and families. These cost effects could be minimized by selecting processed fruits, but fewer nutritional gains would be achieved.

  8. Effect of bulky substituents on thiopyrylium polymethine aggregation in the solid state: A theoretical evaluation of the implications for all-optical switching applications

    KAUST Repository

    Gieseking, Rebecca L.

    2014-11-25

    Polymethine dyes in dilute solutions display many of the optical properties required for all-optical switching applications. However, in thin films, aggregation and polymethine-counterion interactions can substantially modify their properties and limit their utility. Here, we examine the impact of a series of bulky substituents on the solid-state molecular packing of thiopyrylium polymethines by using a theoretical approach combining molecular-dynamics simulations and quantum-chemical calculations. Importantly, it is found that the positions of the substituents near the center and/or ends of the dye determine the extent to which aggregation is reduced; in particular, substituents near the polymethine center primarily modify the type of aggregation that is observed, while substituents near the polymethine ends reduce aggregation and aid in maintaining solution-like properties in the solid state. Our theoretical study elucidates relationships between molecular structure and bulk optical properties and provides design guidelines for all-optical switching materials.

  9. Influence of a polarizable surrounding on the electronically excited states of aggregated perylene materials.

    Science.gov (United States)

    Bellinger, Daniel; Settels, Volker; Liu, Wenlan; Fink, Reinhold F; Engels, Bernd

    2016-06-30

    To tune the efficiency of organic semiconductor devices it is important to understand limiting factors as trapping mechanisms for excitons or charges. An understanding of such mechanisms deserves an accurate description of the involved electronical states in the given environment. In this study, we investigate how a polarizable surrounding influences the relative positions of electronically excited states of dimers of different perylene dyes. Polarization effects are particularly interesting for these systems, because gas phase computations predict that the CT states lie slightly above the corresponding Frenkel states. A polarizable environment may change this energy order because CT states are thought to be more sensitive to a polarizable surrounding than Frenkel states. A first insight we got via a TD-HF approach in combination with a polarizable continuum model (PCM). These give limited insights because TD-HF overestimates excitation energies of CT states. However, SCS-CC2 approaches, which are sufficiently accurate, cannot easily be used in combination with continuum solvent models. Hence, we developed two approaches to combine gas phase SCS-CC2 results with solvent effects based on TD-HF computations. Their accuracies were finally checked via ADC(2)//COSMO computations. The results show that for perylene dyes a polarizable surrounding alone does not influence the energetic ordering of CT and Frenkel states. Variations in the energy order of the states only result from nuclear relaxation effects after the excitation process. © 2016 Wiley Periodicals, Inc.

  10. Testosterone replacement therapy outcomes among opioid users: the Testim Registry in the United States (TRiUS).

    Science.gov (United States)

    Blick, Gary; Khera, Mohit; Bhattacharya, Rajib K; Nguyen, Dat; Kushner, Harvey; Miner, Martin M

    2012-05-01

    Among patients with hypogonadism-associated comorbidities, opioid users have the highest incidence of hypogonadism. Data from the Testim Registry in the United States were analyzed to determine the efficacy of testosterone replacement therapy in opioid users vs nonusers. Prospective, 12-month observational cohort registry. Hypogonadal men (N = 849) prescribed Testim (but not necessarily testosterone replacement) for the first time. Testim 1% testosterone gel (5-10 g/day). Total and free testosterone, sex hormone-binding globulin, prostate-specific antigen, sexual function, mood/depression, and anthropometric data were assessed. Changes from baseline were analyzed using repeated measures mixed-effects analysis of variance; multiple linear regressions of changes in testosterone levels with sexual function, mood, and opioid use were computed. 90/849 patients (10.6%) reported opioid use at baseline; 75/90 (83%) used opioids for ≥ 30 days prior to baseline. Baseline total testosterone and prostate-specific antigen were not statistically different between opioid users and nonusers; there was a trend for higher sex hormone-binding globulin (P = 0.08) and lower free testosterone (P = 0.05) in opioid users. After 1 month, both opioid users and nonusers had significant (P testosterone, which continued through 12 months. Sexual function and mood improved significantly in both opioid users and nonusers over 12 months, and significantly correlated with change in total testosterone. Testosterone replacement therapy increased serum testosterone in hypogonadal opioid users and nonusers alike. The data suggest that with testosterone replacement, hypogonadal opioid users might be expected to have similar improvements in sexual function and mood as opioid nonusers. Wiley Periodicals, Inc.

  11. Mucin biopolymers prevent bacterial aggregation by retaining cells in the free-swimming state

    Science.gov (United States)

    Caldara, Marina; Friedlander, Ronn S.; Kavanaugh, Nicole L.; Aizenberg, Joanna; Foster, Kevin R.; Ribbeck, Katharina

    2013-01-01

    Summary Many species of bacteria form surface-attached communities known as biofilms. Surrounded in secreted polymers, these aggregates are difficult to both prevent and eradicate, posing problems for medicine and industry [1, 2]. Humans play host to hundreds of trillions of microbes that live adjacent to our epithelia and we are typically able to prevent harmful colonization. Mucus, the hydrogel overlying all wet epithelia in the body, can prevent bacterial contact with the underlying tissue. The digestive tract, for example, is lined by a firmly adherent mucus layer that is typically devoid of bacteria, followed by a second, loosely adherent layer that contains numerous bacteria [3]. Here, we investigate mucus's role as a principle arena for host-microbe interactions. Using defined in vitro assays, we found that mucin biopolymers, the main functional constituents of mucus, promote the motility of planktonic bacteria, and prevent their adhesion to underlying surfaces. The deletion of motility genes, however, allows Pseudomonas aeruginosa to overcome the dispersive effects of mucus and form suspended antibiotic-resistant flocs, which mirror the clustered morphology of immotile natural isolates found in the cystic fibrosis lung mucus [4, 5]. Mucus may offer new strategies to target bacterial virulence, such as the design of anti-biofilm coatings for implants. PMID:23142047

  12. UV-light effects on cytochrome c modulated by the aggregation state of phenothiazines.

    Directory of Open Access Journals (Sweden)

    Carolina G dos Santos

    Full Text Available The present study shows the factors that modulate the photodamage promoted by phenothiazines. Cytochrome c was irradiated with UV light for 120 min, over a pH range from 4.0 to 8.0, in the absence and in the presence of different concentrations of thioridazine (TR and fluphenazine (FP. In the absence of phenothiazines, the maximal rate of a Soret band blue shift (nm/min from 409 to 406 nm was obtained at pH 4.0 (0.028 nm/min. The presence of phenothiazines at the concentration range 10-25 µmol/L amplified and accelerated a cytochrome c blue shift (409 to 405 nm, at a rate = 0.041 nm/min. Above 25 µmol/L, crescent concentrations of phenothiazines contributed to cytochrome c protection with (maximal at 2500 µmol/L. Scanning electronic microscopy revealed the formation of nanostructures. The pH also influenced the effect of low phenothiazine concentrations on cytochrome c. Thus, the predominance of phenothiazine-promoted cytochrome c damage or protection depends on a balance of the following factors: the yield of photo-generated drug cation radicals, which is favored by acidic pH; the stability of the cation radicals, which is favored by the drug aggregation; and the cytochrome c structure, modulated by the pH.

  13. Behaviour of fibre reinforced concrete using steel slag coarse aggregate produced in Qatar

    Directory of Open Access Journals (Sweden)

    Alnahhal Wael

    2017-01-01

    Full Text Available The state of Qatar suffers from the shortage of natural resources needed for concrete production. Therefore, it is essential to investigate the feasibility of using by-product recycled materials as aggregates to maintain the concrete construction industry. Several types of recyclable materials are currently used in concrete. One of the potential resources of recycled concrete is steel slag. Knowing that Steel slag is the most significant solid waste generated by Qatar Steel Company in Qatar, replacing of natural coarse aggregate with steel slag aggregate will have a significant environmental and economic impact to the state of Qatar. This paper presents the compression and flexural test results of different concrete mixes made of steel slag coarse aggregate combined with a newly developed basalt chopped fibres. The parameters investigated included the volume fraction of the fibre used and the type of coarse aggregates (natural aggregates “Gabbro” and steel slag aggregates. Plain concrete specimens containing natural coarse aggregates and steel slag aggregates with no fibres added were also tested to serve as control. Test results showed that adding the basalt chopped fibres to the concrete mixes enhanced their flexural tensile strengths at different percentages. In addition, the compressive strength of concrete made with steel slag aggregate was higher than that made with natural gabbro aggregate. Test results clearly showed that steel slag aggregates can be used as sustainable and eco-friendly alternative materials in concrete structures.

  14. [Effect of aggregate state, tonicity, and level of nutrients in media on recovery of Escherichia coli bacteria from heat damage].

    Science.gov (United States)

    Morozov, I I

    1996-01-01

    The influence of aggregate condition, nutrient composition and tonicity of incubation medium on recovery from damages induced by heat at 52 degrees C Escherichia coli B/r and Escherichia coli BS-1 cells was studied. The cells were shown to be recovered from heat damages only in liquid and isotonic medium. The observed increase in a number of viable organisms was not greatly depended on source of energy, plastic material and macroelements of incubation medium. The recovered cells showed increase of osmotic tolerance to hyper- and hypotonic shock similar to intact cells. No increase in survivors was observed when heated cells were incubated on solid and/or anisotonic medium. The additional cell killing and high osmosensitivity may be seen in this case. The role of the system of osmotic homeostasis, including membrane state, in the modification of cell viability and osmoresistance of heated bacterial cells was discussed on the base of the data obtained.

  15. The problem of a self-consistent description of the equilibrium distribution of particles in three states of aggregation

    Science.gov (United States)

    Tovbin, Yu. K.

    2006-10-01

    The possibility of unified self-consistent calculations of equilibrium distributions of molecules in three states of aggregation within the framework of the lattice gas model is considered. The corresponding approach was generalized to arbitrary pressures with including the compressibility of lattice structures. Closed equations were obtained for calculating thermodynamic functions (including an equation for the chemical potential of mixture components) in the continuum quasi-chemical approximation. Their use ensures equally accurate calculations of interphase equilibria in gas-liquid-solid systems and the determination of the triple and critical points. Possibilities for simplifying the equations by passing to the effective pair interaction potential, which takes into account averaged vibrations and volume accessible to the translational motion of molecules of commensurate sizes, are considered.

  16. Contribution of Aggregate States and Energetic Disorder to a Squaraine System Targeted for Organic Photovoltaic Devices.

    Science.gov (United States)

    Zheng, Chenyu; Penmetcha, Anirudh Raju; Cona, Brandon; Spencer, Susan D; Zhu, Bi; Heaphy, Patrick; Cody, Jeremy A; Collison, Christopher J

    2015-07-21

    Squaraine dyes have significant potential for use in organic photovoltaic devices because their chemical and packing structure tunability leads to a broad solid state panchromaticity. Nevertheless, broadening of the spectrum does not always give rise to increasing power conversion efficiencies. Furthermore, the same processing strategy used to make devices from different squaraines does not lead to the same optimized performance. In this work, by varying the environmental conditions of a set of anilinic squaraines, we demonstrate that spin-cast thin films are made up of a complex set of states, with each state contributing differently to the overall device efficiency. We demonstrate crystallochromy in that small changes in the packing structure give rise to dramatically different absorption spectra. Through a remarkable comparison between squaraines in poly(methyl methacrylate) solid solution and squaraine:PC60BM blends, we also show long-range and orientational disorder broadening, which distorts the ability to correlate qualitative spectroscopic assessment with an understanding of the device mechanism. We conclude that a full quantitative assessment of the populations of each excited state must be carried out in order to make progress toward an improved understanding of each state's contribution to charge transfer at the bulk heterojunction interface.

  17. Solid-state NMR spectroscopic trends for supramolecular assemblies and protein aggregates.

    Science.gov (United States)

    Linser, Rasmus

    2017-08-24

    Solid-state NMR is able to generate structural data on sample preparations that are explicitly non-crystalline. In particular, for amyloid fibril samples, which can comprise significant degrees of sample disorder, solid-state NMR has been used very successfully. But also solid-state NMR studies of other supramolecular assemblies that have resisted assessment by more standard methods are being performed with increasing ease and biological impact, many of which are briefly reviewed here. New technical trends with respect to structure calculation, protein dynamics and smaller sample amounts have reshaped the field of solid-state NMR recently. In particular, proton-detected approaches based on fast Magic-Angle Spinning (MAS) were demonstrated for crystalline systems initially. Currently, such approaches are being expanded to the above-mentioned non-crystalline targets, the characterization of which can now be pursued with sample amounts on the order of a milligram. In this Trends article, I am giving a brief overview about achievements of the last years as well as the directions that the field has been heading into and delineate some satisfactory perspectives for solid-state NMR's future striving. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Helium Droplets as Nano-Cryostats for Molecular Spectroscopy: Aggregation, State Selection and Electron Spin Resonance

    Science.gov (United States)

    Ernst, Wolfgang E.

    2009-06-01

    Droplets of about 10^{4} helium atoms generated in a supersonic expansion, represent a nanometer-sized superfluid medium of 0.4 K temperature and can be doped with one or several atoms or molecules that may form complexes in this cold environment. Using two-laser excitation schemes, we were able to identify the alkali trimers K_3, Rb_3, K_2Rb and KRb_2 in their lowest quartet states formed on helium droplets loaded with potassium and rubidium atoms and assign several excited states that underlie both Jahn-Teller and spin-orbit coupling. As helium provides a gentle and only weakly perturbing matrix, it appeared desirable to look for ways to measure fine and hyperfine structure directly in the microwave or radiofrequency regime. In preparation for experiments involving optical detection of electron spin transitions in cold molecules, we studied the electronic spin relaxation in alkali atoms and molecules that reside on the surface of a droplet. Measurements of the circular dichroism in the presence of a magnetic field showed that the populations of Zeeman sublevels in alkali atoms are not thermalized, while for dimers and trimers a temperature of 0.4 K was found, implicitly providing a first determination of the droplet's surface temperature. Optical detection of spin resonance is achieved in an optical pump-probe experiment with the electron spin transition induced in a microwave cavity in a magnetic field between the pump and probe regions. With the pump laser depleting a particular spin state by desorption of the species from the droplet beam or by optical pumping, the probe laser detects the successful spin flip induced by the microwave field. Examples will be presented showing up to 50 Rabi cycles of an electron spin transition on an alkali doped helium droplet during the flight time of 57 μs through the cavity. J. Nagl, G. Auböck, A. W. Hauser, O. Allard, C. Callegari, and W. E. Ernst, Phys. Rev. Lett. 100, 063001(2008)} G. Auböck, J. Nagl, C. Callegari, and

  19. Binding of vanadium compounds perturbs conformation and aggregation state of insulin

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The interactions between zinc-free insulin and vanadium compounds, NaVO3, VO(acac)2 and VO(ma)2, have been investigated by fluorescence spectroscopy, circular dichroism (CD) and Fourier-transformed infrared (FT-IR) spectroscopy. The results showed that binding of vanadium compounds produced a static quenching of the intrinsic fluorescence of insulin. The apparent association constants were determined to be (0.17±0.01)×104 L*mol-1 for NaVO3, (2.8±0.2)×104 L*mol-1 for VO(acac)2, and (4.0±0.1)×104 L*mol-1 for VO(ma)2, respectively. The light scattering intensity of insulin decreased upon incubation with the vanadium compounds, suggesting the disaggregation of insulin. The attenuation of the band at 273 nm of insulin CD spectra also supported the disaggregation of insulin observed above. A new band at 1650~1653 cm-1 appeared in the FT-IR spectra of insulin upon incubation with the vanadium compounds, indicating the formation of an α-helix structure at B (9-19) motif. This α-helix structure suggests a structural change of insulin from an extended conformation (T state) to a helical conformation (R state), which is essential for binding of insulin to its receptor. In conclusion, binding of vanadium compounds results in conformational changes and disaggregation of insulin. These changes might account for the enhancement of binding affinity for insulin to its receptor in the presence of vanadium compounds.

  20. Arsenic (+3 oxidation state methyltransferase is a specific but replaceable factor against arsenic toxicity

    Directory of Open Access Journals (Sweden)

    Maki Tokumoto

    2014-01-01

    Full Text Available Inorganic metalloids, such as arsenic (As, antimony (Sb, selenium (Se, and tellurium (Te, are methylated in biota. In particular, As, Se, and Te are methylated and excreted in urine. The biomethylation is thought to be a means to detoxify the metalloids. The methylation of As is catalyzed by arsenic (+3 oxidation state methyltransferase (AS3MT. However, it is still unclear whether AS3MT catalyzes the methylation of the other metalloids. It is also unclear whether other factors catalyze the As methylation instead of AS3MT. Recombinant human AS3MT (rhAS3MT was prepared and used in the in vitro methylation of As, Se, and Te. As, but not Se and Te, was specifically methylated in the presence of rhAS3MT. Then, siRNA targeting AS3MT was introduced into human hepatocarcinoma (HepG2 cells. Although AS3MT protein expression was completely silenced by the gene knockdown, no increase in As toxicity was found in the HepG2 cells transfected with AS3MT-targeting siRNA. We conclude that AS3MT catalyzes the methylation of As and not other biomethylatable metalloids, such as Se and Te. We speculate that other methylation enzyme(s also catalyze the methylation of As in HepG2 cells.

  1. Unfolding pathway of CotA-laccase and the role of copper on the prevention of refolding through aggregation of the unfolded state

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Andre T. [Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Av. da Republica, 2780-157 Oeiras (Portugal); Lopes, Carlos [Centre for Molecular and Structural Biomedicine, Institute for Biotechnology and Bioengineering, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal); Martins, Ligia O. [Instituto de Tecnologia Quimica e Biologica, Universidade Nova de Lisboa, Av. da Republica, 2780-157 Oeiras (Portugal); Melo, Eduardo Pinho, E-mail: emelo@ualg.pt [Centre for Molecular and Structural Biomedicine, Institute for Biotechnology and Bioengineering, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro (Portugal)

    2012-06-08

    Highlights: Black-Right-Pointing-Pointer CotA-laccase unfolds with an intermediate state. Black-Right-Pointing-Pointer Copper stabilizes the native and the intermediate state. Black-Right-Pointing-Pointer Copper binding to the unfolded state prevents refolding through protein aggregation. Black-Right-Pointing-Pointer Copper incorporation in CotA-laccase occurs as a later step during folding. -- Abstract: Copper is a redox-active metal and the main player in electron transfer reactions occurring in multicopper oxidases. The role of copper in the unfolding pathway and refolding of the multicopper oxidase CotA laccase in vitro was solved using double-jump stopped-flow experiments. Unfolding of apo- and holo-CotA was described as a three-state process with accumulation of an intermediate in between the native and unfolded state. Copper stabilizes the native holo-CotA but also the intermediate state showing that copper is still bound to this state. Also, copper binds to unfolded holo-CotA in a non-native coordination promoting CotA aggregation and preventing refolding to the native structure. These results gather information on unfolding/folding pathways of multicopper oxidases and show that copper incorporation in vivo should be a tight controlled process as copper binding to the unfolded state under native conditions promotes protein aggregation.

  2. Assessing the Use of Aggregate Data in the Evaluation of School-Based Interventions: Implications for Evaluation Research and State Policy Regarding Public-Use Data

    Science.gov (United States)

    Jacob, Robin T.; Goddard, Roger D.; Kim, Eun Sook

    2014-01-01

    It is often difficult and costly to obtain individual-level student achievement data, yet, researchers are frequently reluctant to use school-level achievement data that are widely available from state websites. We argue that public-use aggregate school-level achievement data are, in fact, sufficient to address a wide range of evaluation questions…

  3. Online Coupling of Flow-Field Flow Fractionation and Single Particle Inductively Coupled Plasma-Mass Spectrometry: Characterization of Nanoparticle Surface Coating Thickness and Aggregation State

    Science.gov (United States)

    Surface coating thickness and aggregation state have strong influence on the environmental fate, transport, and toxicity of engineered nanomaterials. In this study, flow-field flow fractionation coupled on-line with single particle inductively coupled plasma-mass spectrometry i...

  4. COORDINATION STATE AND AGGREGATION PROCESS OF BACTERIOCHLOROPHYLL A AND ITS DERIVATIVES : STUDY ON ACETONE-WATER AND METHANOL-WATER SOLVENTS

    Directory of Open Access Journals (Sweden)

    Heriyanto Heriyanto

    2010-06-01

    Full Text Available Research on bacteriochlorophyll (BChl a and its derivatives had been conducted to determine the coordination state and the aggregation process in acetone-water and methanol-water. The results showed that there were mainly two absorption peaks in BChl a and its derivatives, namely: Qx and Qy that were very sensitive to coordination state and aggregation process. The coordination state of pigment could be determined based on Qx absorption peak that was influenced by solvents. In addition, the donor number (DN and taft parameters (β and π* from each sovents could also be used to determine the coordination state. One or two of axial coordination toward center metal of BChl a and its derivatives have to be filled by donor electron as a foreign nucleophile. Mg-BChl was exist as five-coordinate complexes in acetone but as six-coordinate complexes in methanol. Five-coordinate complexes of Zn-BChl was occurred either in acetone or methanol. Cu-BChl was exist as four-coordinate complexes in acetone but altered to five-coordinate complexes in methanol. The agregation process was influenced by the existence of water added in pigment solution. The order of Mg-BChl a and its derivatives abilities to form new aggregate in acetone-water and methanol-water, in regard of water-addition percentage was as follow: Cu-BChl > Zn-BChl > Mg-BChl. Methanol was the solvent that could form aggregate of Mg-BChl and its derivatives at lower water-addition percentage compared to acetone.   Keywords: aggregation, bacteriochlorophyll & its derivatives, coordination state.

  5. Ankle replacement

    Science.gov (United States)

    Ankle arthroplasty - total; Total ankle arthroplasty; Endoprosthetic ankle replacement; Ankle surgery ... You may not be able to have a total ankle replacement if you have had ankle joint infections in ...

  6. Knee Replacement

    Science.gov (United States)

    Knee replacement is surgery for people with severe knee damage. Knee replacement can relieve pain and allow you to ... Your doctor may recommend it if you have knee pain and medicine and other treatments are not ...

  7. Tillage Practices in the Conterminous United States, 1989-2004--Datasets by Aggregated Watershed; ds573_tillage_lu01

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is an aggregation of county-level tillage practices to the 8-digit hydrologic unit watershed. The original county-level data were collected by the...

  8. Tillage Practices in the Conterminous United States, 1989-2004--Datasets Aggregated by Watershed; tillage_lu92e

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset is an aggregation of county-level tillage practices to the 8-digit hydrologic unit watershed. The original county-level data were collected by the...

  9. Impact of Interfacial Molecular Conformation and Aggregation State on the Energetic Landscape and Performance in Organic Photovoltaics

    KAUST Repository

    Ngongang Ndjawa, Guy Olivier

    2016-11-25

    In organic photovoltaics (OPVs) the key processes relevant to device operation such as exciton dissociation and free carriers recombination occur at the donor-acceptor (D-A) interface. OPV devices require the bulk heterojunction (BHJ) architecture to function efficiently. In these BHJs, D-A interfaces are arranged in three dimensions, which makes molecular arrangements at these interfaces ill defined and hard to characterize. In addition, molecular materials used in OPVs are inherently disordered and may exhibit variable degrees of structural order in the same BHJ. Yet, D-A molecular arrangements and structure are crucial because they shape the energy landscape and photovoltaic (PV) performance in OPVs. Studies that use well-defined model systems to look in details at the interfacial molecular structure in OPVs and link it to interfacial energy landscape and device operation are critically lacking. We have used in situ photoelectron spectroscopy and ex situ x-ray scattering to study D-A interfaces in tailored bilayers and BHJs based on small molecule donors. We show preferential miscibility at the D-A interface depending on molecular conformation in zinc phthalocyanine (ZnPc)/ C60 bilayers and we derive implications for exciton dissociation. Using sexithiophene (6T), a crystalline donor, we show that the energy landscape at the D-A interface varies markedly depending on the molecular composition of the BHJ. Both the ionization energies of sexithiophene and C60 shift by over ~0.4 eV while the energy of the charge transfer state shifts by ~0.5 eV depending on composition. Such shifts create a downward energy landscape that helps interfacial excitons to overcome their binding energies. Finally, we demonstrate that when both disordered and ordered phases of D coexist at the interface, low-lying energy states form in ordered phases and significantly limit the Voc in devices. Overall our work underlines the importance of the aggregation and conformation states of

  10. Investigation of cement based composites made with recycled rubber aggregate

    Directory of Open Access Journals (Sweden)

    Jevtić Dragica Lj.

    2012-01-01

    Full Text Available The results of experimental investigations performed on cement based composites made with addition of recycled rubber as a partial replacement of natural river aggregate are presented in this paper. Different properties of cement based mortar were analyzed, both in fresh and in hardened state. Tested properties in the fresh state included: density, consistency and volume of entrained air. In the hardened state, the following properties were tested: density, mechanical properties (compressive and flexural strength, modulus of elasticity, adhesion to concrete substrate, water absorption, freeze-thaw resistance and ultrasonic pulse velocity. The obtained results indicate that recycled rubber can be successfully applied as a partial replacement of natural river aggregate in cement based composites, in accordance with the sustainable development concept. The investigation showed that physical-mechanical properties of cementituous composites depend to a great extent on the percentage of replacement of natural river aggregate with recycled rubber, especially when the density, strength, adhesion and freeze-thaw resistance are concerned. The best results were obtained in the freeze-thaw resistance of such composites.

  11. Use of testosterone replacement therapy in the United States and its effect on subsequent prostate cancer outcomes.

    Science.gov (United States)

    Kaplan, Alan L; Hu, Jim C

    2013-08-01

    To assess utilization trends and determine the effect of testosterone replacement therapy on outcomes in men who subsequently developed prostate cancer. We used linked Surveillance, Epidemiology, and End Results-Medicare data to identify 149,354 men diagnosed with prostate cancer from 1992 to 2007. Of those, 2,237 men (1.5%) underwent testosterone replacement therapy before their prostate cancer diagnosis. Propensity scoring methods were used to assess cancer-specific outcomes of testosterone replacement vs no replacement therapy. Testosterone replacement was associated with older age at cancer diagnosis, nonwhite race, and higher comorbidity (P testosterone vs testosterone before the prostate cancer diagnosis was associated with higher grade (34% vs 30%, P therapy after initial treatment. Through our observational study design, we show that testosterone use was low throughout the study period. Testosterone use was not associated with aggressive prostate cancer and did not affect overall or disease-specific mortality. Although our findings support growing evidence that testosterone replacement is safe with respect to prostate cancer, confirmatory prospective studies are needed. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Identification of a conserved aggregation-prone intermediate state in the folding pathways of Spc-SH3 amyloidogenic variants.

    Science.gov (United States)

    Krobath, H; Estácio, S G; Faísca, P F N; Shakhnovich, E I

    2012-10-05

    We compared the folding pathways of selected mutational variants of the α-spectrin SH3 domain (Spc-SH3) by using a continuum model that combines a full atomistic protein representation with the Gō potential. Experimental data show that the N47G mutant shows very little tendency to aggregate while the N47A and triple mutant D48G(2Y) are both amyloidogenic, with the latter being clearly more aggregation prone. We identified a strikingly similar native-like folding intermediate across the three mutants, in which strand β(1) is totally unstructured and more than half of the major hydrophobic core residues are highly solvent exposed. Results from extensive docking simulations show that the ability of the intermediates to dimerize is largely driven by strand β(1) and is consistent with the in vitro aggregation behavior reported for the corresponding mutants. They further suggest that residues 44 and 53, which are key players in the nucleation-condensation mechanism of folding, are also important triggers of the aggregation process. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Predicting protein aggregation during storage in lyophilized solids using solid state amide hydrogen/deuterium exchange with mass spectrometric analysis (ssHDX-MS).

    Science.gov (United States)

    Moorthy, Balakrishnan S; Schultz, Steven G; Kim, Sherry G; Topp, Elizabeth M

    2014-06-02

    Solid state amide hydrogen/deuterium exchange with mass spectrometric analysis (ssHDX-MS) was used to assess the conformation of myoglobin (Mb) in lyophilized formulations, and the results correlated with the extent of aggregation during storage. Mb was colyophilized with sucrose (1:1 or 1:8 w/w), mannitol (1:1 w/w), or NaCl (1:1 w/w) or in the absence of excipients. Immediately after lyophilization, samples of each formulation were analyzed by ssHDX-MS and Fourier transform infrared spectroscopy (FTIR) to assess Mb conformation, and by dynamic light scattering (DLS) and size exclusion chromatography (SEC) to determine the extent of aggregation. The remaining samples were then placed on stability at 25 °C and 60% RH or 40 °C and 75% RH for up to 1 year, withdrawn at intervals, and analyzed for aggregate content by SEC and DLS. In ssHDX-MS of samples immediately after lyophilization (t = 0), Mb was less deuterated in solids containing sucrose (1:1 and 1:8 w/w) than in those containing mannitol (1:1 w/w), NaCl (1:1 w/w), or Mb alone. Deuterium uptake kinetics and peptide mass envelopes also indicated greater Mb structural perturbation in mannitol, NaCl, or Mb-alone samples at t = 0. The extent of deuterium incorporation and kinetic parameters related to rapidly and slowly exchanging amide pools (Nfast, Nslow), measured at t = 0, were highly correlated with the extent of aggregation on storage as measured by SEC. In contrast, the extent of aggregation was weakly correlated with FTIR band intensity and peak position measured at t = 0. The results support the use of ssHDX-MS as a formulation screening tool in developing lyophilized protein drug products.

  14. Long-Term Survival of Dialysis Patients with Bacterial Endocarditis Undergoing Valvular Replacement Surgery in the United States

    Science.gov (United States)

    Leither, Maxwell D.; Shroff, Gautam R.; Ding, Shu; Gilbertson, David T.; Herzog, Charles A.

    2013-01-01

    Background Bacterial endocarditis in dialysis patients is associated with high mortality rates. The literature is limited regarding long-term outcomes of valvular replacement surgery and choice of prosthesis in dialysis patients with bacterial endocarditis. Methods and Results Dialysis patients hospitalized for bacterial endocarditis, 2004-2007, were studied retrospectively using data from the US Renal Data System. Long-term survival of patients undergoing valve replacement surgery with tissue or non-tissue valves was compared using the Kaplan-Meier method. A Cox proportional hazards model was used to identify independent predictors of mortality in patients undergoing valvular replacement surgery. During the study period, 11,156 dialysis patients were hospitalized for bacterial endocarditis and 1267 (11.4%) underwent valvular replacement surgery (tissue valve 44.3%, non-tissue valve 55.7%). In the valve replacement cohort, 60% were men, 50% white, 54% aged 45-64 years, and 36% diabetic. Estimated survival with tissue and non-tissue valves, respectively, at 0.5, 1, 2, and 3 years was 59% and 60%, 48% and 50%, 35% and 37%, and 25% and 30% (log rank P = 0.42). Staphylococcus was the predominant organism (66% of identified organisms). Independent predictors of mortality in patients undergoing valve replacement surgery included older age, diabetes as cause of end-stage renal disease, surgery during index hospitalization, staphylococcus as the causative organism, and dysrhythmias as a comorbid condition. Conclusions Valve replacement surgery is appropriate for well-selected dialysis patients with bacterial endocarditis, but is associated with high mortality rates. Survival does not differ with tissue or non-tissue prosthesis. PMID:23785002

  15. Proteins aggregation and human diseases

    Science.gov (United States)

    Hu, Chin-Kun

    2015-04-01

    Many human diseases and the death of most supercentenarians are related to protein aggregation. Neurodegenerative diseases include Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), frontotemporallobar degeneration, etc. Such diseases are due to progressive loss of structure or function of neurons caused by protein aggregation. For example, AD is considered to be related to aggregation of Aβ40 (peptide with 40 amino acids) and Aβ42 (peptide with 42 amino acids) and HD is considered to be related to aggregation of polyQ (polyglutamine) peptides. In this paper, we briefly review our recent discovery of key factors for protein aggregation. We used a lattice model to study the aggregation rates of proteins and found that the probability for a protein sequence to appear in the conformation of the aggregated state can be used to determine the temperature at which proteins can aggregate most quickly. We used molecular dynamics and simple models of polymer chains to study relaxation and aggregation of proteins under various conditions and found that when the bending-angle dependent and torsion-angle dependent interactions are zero or very small, then protein chains tend to aggregate at lower temperatures. All atom models were used to identify a key peptide chain for the aggregation of insulin chains and to find that two polyQ chains prefer anti-parallel conformation. It is pointed out that in many cases, protein aggregation does not result from protein mis-folding. A potential drug from Chinese medicine was found for Alzheimer's disease.

  16. J-aggregation, its impact on excited state dynamics and unique solvent effects on macroscopic assembly of a core-substituted naphthalenediimide

    KAUST Repository

    Kar, Haridas

    2015-03-12

    Herein we reveal a straightforward supramolecular design for the H-bonding driven J-aggregation of an amine-substituted cNDI in aliphatic hydrocarbons. Transient absorption spectroscopy reveals sub-ps intramolecular electron transfer in isolated NDI molecules in a THF solution followed by a fast recombination process, while a remarkable extension of the excited state lifetime by more than one order of magnitude occurred in methylcyclohexane likely owing to an increased charge-separation as a result of better delocalization of the charge-separated states in J-aggregates. We also describe unique solvent-effects on the macroscopic structure and morphology. While J-aggregation with similar photophysical characteristics was noticed in all the tested aliphatic hydrocarbons, the morphology strongly depends on the “structure” of the solvents. In linear hydrocarbons (n-hexane, n-octane, n-decane or n-dodecane), formation of an entangled fibrillar network leads to macroscopic gelation while in cyclic hydrocarbons (methylcyclohexane or cyclohexane) although having a similar polarity, the cNDI exhibits nanoscale spherical particles. These unprecedented solvent effects were rationalized by establishing structure-dependent specific interactions of the solvent molecules with the cNDI which may serve as a general guideline for solvent-induced morphology-control of structurally related self-assembled materials.

  17. Trends in Vascular Complications in High-Risk Patients Following Transcatheter Aortic Valve Replacement in the United States.

    Science.gov (United States)

    Ando, Tomo; Akintoye, Emmanuel; Telila, Tesfaye; Briasoulis, Alexandros; Takagi, Hisato; Grines, Cindy L; Afonso, Luis

    2017-02-10

    Vascular complications (VC) following transcatheter aortic valve replacement (TAVR) are associated with worse outcomes. The trend of VC incidence in patients considered high risk is unclear. We sought to assess the trend of VC after TAVR in patients at high risk. We investigated the VC trend in female, diabetes mellitus, and peripheral vascular disease (PVD) patients. Patients who underwent TAVR from 2011 to 2014 in the United States were identified using the International Classification of Diseases-Ninth Revision code 35.05 from the Nationwide Inpatient Sample database. Frequency of any VC (per 100 transcatheter aortic valve implantation procedure or hospital discharges) for each year from 2011 to 2014 was assessed for the overall population as well as within each category of high-risk cohorts. The overall VC rate was 6.0% (2,044/33,790). Patients who had VC were more likely to be female and had higher rates of PVD at baseline. The annual rate of VC in the overall population from 2011 to 2014 was 4.6%, 9.4%, 6.8%, and 4.4%, respectively. There was a significant increase in VC rate from 2011 to 2012 (p = 0.03), whereas there was a significant decrease in VC rate from 2012 to 2014 (p <0.001). The rate of VC between 2011 and 2014 was similar (p = 0.82). The rate of VC did not increase in any of the high-risk groups from 2011 to 2012. However, the rate of VC from 2012 to 2014 decreased significantly in all the high-risk groups. The VC rate was similar for groups between 2011 and 2014. The overall VC rate among TAVR patients initially increased from 2011 to 2012 but decreased thereafter. Similar trend in VC rate was found among high-risk patients except that the initial increase in rates from 2011 to 2012 did not reach statistical significance. Whether further reduction in VC with improvement in devices and operator/center experience for both overall and high-risk groups in TAVR occurs will require continuous longitudinal monitoring.

  18. Knee Replacement

    Science.gov (United States)

    ... need knee replacement surgery usually have problems walking, climbing stairs, and getting in and out of chairs. Some ... a total living space on one floor since climbing stairs can be difficult. Install safety bars or a ...

  19. Fine natural aggregate replacement for sandy residue from itabirite exploitation in Portland cement mortar; Substituicao dos agregados miudos naturais por residuo arenoso gerado no beneficiamento do itabirito em argamassas de cimento Portland

    Energy Technology Data Exchange (ETDEWEB)

    Melo, V.A.R. [Rede Tematica em Engenharia de Materiais (REDEMAT), MG (Brazil); Freire, C.B.; Pereira Junior, S.S.; Lameiras, F.S.; Tello, C.C.O., E-mail: cbf@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2011-07-01

    The fine natural aggregates are a material largely used by the civil construction for mortar and concrete production. Due to tightening legal restrictions imposed on their extraction, alternative materials are being considered. The use of sandy residue from BIF (banded iron formations) exploitation was investigated. It requires their grinding and flotation to concentrate iron oxides. Large amounts of sandy residue composed of quartz and iron oxides are generated in this process. The sandy residue was characterized relative to mineralogical composition, particle size distribution, presence of organic impurities, and particle shape. Mortar formulations were prepared by varying the type of cement, the cement to aggregate proportion and the water/cement ratio (a/c). The results of viscosity and density of fresh mortar, setting time, and compressive strength are presented. Compressive strength up to 19.5 MPa at 28 days were achieved with the use of cement CPV, a/c ratio of 0.80 and cement:aggregate proportion of 1:2. The results demonstrate the technical feasibility of using sandy residue as fine aggregate. (author)

  20. Improving the dispersity of detonation nanodiamond: differential scanning calorimetry as a new method of controlling the aggregation state of nanodiamond powders.

    Science.gov (United States)

    Korobov, Mikhail V; Volkov, Dmitry S; Avramenko, Natalya V; Belyaeva, Lubov' A; Semenyuk, Pavel I; Proskurnin, Mikhail A

    2013-02-21

    Detonation nanodiamond (ND) is a suitable source material to produce unique samples consisting of almost uniform diamond nanocrystals (d = 3-5 nm). Such samples exist in the form of long stable aqueous dispersions with narrow size distribution of diamond particles. The material is finding ever increasing application in biomedicine. The major problem in producing monodispersed diamond colloids lies in the necessity of deagglomeration of detonation soot and/or removing of clusters formed by already isolated core particles in dry powders. To do this one must have an effective method to monitor the aggregation state or dispersity of powders and gels prior to the preparation of aqueous dispersions. In the absence of dispersity control at various stages of preparation the reproducibility of properties of existing ND materials is poor. In this paper we introduce differential scanning calorimetry (DSC) as a new tool capable to distinguish the state of aggregation in dry and wetted ND materials and to follow changes in this state under different types of treatment. Samples with identical X-ray diffraction patterns (XRD) and high resolution transmission electron microscopy (HRTEM) images gave visibly different DSC traces. Strong correlation was found between dynamic light scattering (DLS) data for colloids and DSC parameters for gels and powders of the same material. Based on DSC data we improved dispersity of existing ND materials and isolated samples with the best possible DSC parameters. These were true monodispersed easily dispersible fractions of ND particles with diameters of ca. 3 nm.

  1. A Study of Concrete Made with Fine and Coarse Aggregates Recycled from Fresh Concrete Waste

    Directory of Open Access Journals (Sweden)

    Mamery Sérifou

    2013-01-01

    Full Text Available This paper deals with the possibility of using fresh concrete waste as recycled aggregates in concrete. An experimental program based on two variables (proportion of fine aggregates replacement and proportion of coarse aggregates replacement was implemented. The proportions of replacement were 0%, 50%, and 100% by mass of aggregates. Several mechanical properties were tested as compressive and tensile strengths. The results show a good correlation between aggregates replacement percentage and concrete properties. Concerning mechanical properties, a gradual decrease in compressive, splitting, and flexural strengthn with the increase in recycled aggregate percentage is shown.

  2. Study of Bond Characteristics of Reinforced Waste Glass Aggregate Concrete

    Science.gov (United States)

    Rajagopalan, P.; Balaji, V.; Unnikrishnan, N.; Jainul Haq, T.; Bhuvaneshwari, P.

    2017-07-01

    The conformity of properties of waste glass aggregate with conventional aggregate was found out. Nine cubes (150mm x 150mm x 150mm) were cast out of which three were used for control concrete, three were fully replaced with waste glass as coarse aggregate, three were partially replaced(50%) with waste glass as fine aggregate. Six cylinders (150mm x 300mm) were cast out of which two for control concrete, two cylinders with coarse aggregate fully replaced with waste glass aggregate(WGA) and remaining two cylinders with partially replaced (50%) fine aggregate with waste glass aggregate. Cured specimens were subjected to compression and split-tensile test to ascertain the characteristic compressive strength and split tensile strength. Since the surface of the coarse aggregate plays a significant role in bonding of the rebar in reinforced concrete, pull-out test on both control and Waste Glass Aggregate (WGA) cube specimens (150mm x 150mm with 20mm diameter steel rods) were conducted. Scanning Electron Microscopy (SEM) analysis has been done for better understanding of bonding properties in waste glass fine aggregate(WGFA) and waste glass coarse aggregate(WGCA) concrete. Comparison of the results with that of control specimens showed that waste glass could be effectively used as aggregates in reinforced concrete construction.

  3. Esophageal replacement.

    Science.gov (United States)

    Kunisaki, Shaun M; Coran, Arnold G

    2017-04-01

    This article focuses on esophageal replacement as a surgical option for pediatric patients with end-stage esophageal disease. While it is obvious that the patient׳s own esophagus is the best esophagus, persisting with attempts to retain a native esophagus with no function and at all costs are futile and usually detrimental to the overall well-being of the child. In such cases, the esophagus should be abandoned, and the appropriate esophageal replacement is chosen for definitive reconstruction. We review the various types of conduits used for esophageal replacement and discuss the unique advantages and disadvantages that are relevant for clinical decision-making. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Pre-Saturation Technique of the Recycled Aggregates: Solution to the Water Absorption Drawback in the Recycled Concrete Manufacture

    Directory of Open Access Journals (Sweden)

    Julia García-González

    2014-09-01

    Full Text Available The replacement of natural aggregates by recycled aggregates in the concrete manufacturing has been spreading worldwide as a recycling method to counteract the large amount of construction and demolition waste. Although legislation in this field is still not well developed, many investigations demonstrate the possibilities of success of this trend given that concrete with satisfactory mechanical and durability properties could be achieved. However, recycled aggregates present a low quality compared to natural aggregates, the water absorption being their main drawback. When used untreated in concrete mix, the recycled aggregate absorb part of the water initially calculated for the cement hydration, which will adversely affect some characteristics of the recycled concrete. This article seeks to demonstrate that the technique of pre-saturation is able to solve the aforementioned problem. In order to do so, the water absorption of the aggregates was tested to determine the necessary period of soaking to bring the recycled aggregates into a state of suitable humidity for their incorporation into the mixture. Moreover, several concrete mixes were made with different replacement percentages of natural aggregate and various periods of pre-saturation. The consistency and compressive strength of the concrete mixes were tested to verify the feasibility of the proposed technique.

  5. Construction aggregates

    Science.gov (United States)

    Nelson, T.I.; Bolen, W.P.

    2007-01-01

    Construction aggregates, primarily stone, sand and gravel, are recovered from widespread naturally occurring mineral deposits and processed for use primarily in the construction industry. They are mined, crushed, sorted by size and sold loose or combined with portland cement or asphaltic cement to make concrete products to build roads, houses, buildings, and other structures. Much smaller quantities are used in agriculture, cement manufacture, chemical and metallurgical processes, glass production and many other products.

  6. Near-infrared excited state dynamics of melanins: the effects of iron content, photo-damage, chemical oxidation, and aggregate size.

    Science.gov (United States)

    Simpson, Mary Jane; Wilson, Jesse W; Robles, Francisco E; Dall, Christopher P; Glass, Keely; Simon, John D; Warren, Warren S

    2014-02-13

    Ultrafast pump-probe measurements can discriminate the two forms of melanin found in biological tissue (eumelanin and pheomelanin), which may be useful for diagnosing and grading melanoma. However, recent work has shown that bound iron content changes eumelanin's pump-probe response, making it more similar to that of pheomelanin. Here we record the pump-probe response of these melanins at a wider range of wavelengths than previous work and show that with shorter pump wavelengths the response crosses over from being dominated by ground-state bleaching to being dominated by excited-state absorption. The crossover wavelength is different for each type of melanin. In our analysis, we found that the mechanism by which iron modifies eumelanin's pump-probe response cannot be attributed to Raman resonances or differences in melanin aggregation and is more likely caused by iron acting to broaden the unit spectra of individual chromophores in the heterogeneous melanin aggregate. We analyze the dependence on optical intensity, finding that iron-loaded eumelanin undergoes irreversible changes to the pump-probe response after intense laser exposure. Simultaneously acquired fluorescence data suggest that the previously reported "activation" of eumelanin fluorescence may be caused in part by the dissociation of metal ions or the selective degradation of iron-containing melanin.

  7. Recycled aggregates concrete: aggregate and mix properties

    Directory of Open Access Journals (Sweden)

    González-Fonteboa, B.

    2005-09-01

    Full Text Available This study of structural concrete made with recycled concrete aggregate focuses on two issues: 1. The characterization of such aggregate on the Spanish market. This involved conducting standard tests to determine density, water absorption, grading, shape, flakiness and hardness. The results obtained show that, despite the considerable differences with respect to density and water absorption between these and natural aggregates, on the whole recycled aggregate is apt for use in concrete production. 2. Testing to determine the values of basic concrete properties: mix design parameters were established for structural concrete in non-aggressive environments. These parameters were used to produce conventional concrete, and then adjusted to manufacture recycled concrete aggregate (RCA concrete, in which 50% of the coarse aggregate was replaced by the recycled material. Tests were conducted to determine the physical (density of the fresh and hardened material, water absorption and mechanical (compressive strength, splitting tensile strength and modulus of elasticity properties. The results showed that, from the standpoint of its physical and mechanical properties, concrete in which RCA accounted for 50% of the coarse aggregate compared favourably to conventional concrete.

    Se aborda el estudio de hormigones estructurales fabricados con áridos reciclados procedentes de hormigón, incidiéndose en dos aspectos: 1. Caracterización de tales áridos, procedentes del mercado español. Para ello se llevan a cabo ensayos de densidad, absorción, granulometría, coeficiente de forma, índice de lajas y dureza. Los resultados obtenidos han puesto de manifiesto que, a pesar de que existen diferencias notables (sobre todo en cuanto a densidad y absorción con los áridos naturales, las características de los áridos hacen posible la fabricación de hormigones. 2. Ensayos sobre propiedades básicas de los hormigones: se establecen parámetros de dosificaci

  8. Observing Convective Aggregation

    Science.gov (United States)

    Holloway, Christopher E.; Wing, Allison A.; Bony, Sandrine; Muller, Caroline; Masunaga, Hirohiko; L'Ecuyer, Tristan S.; Turner, David D.; Zuidema, Paquita

    2017-06-01

    Convective self-aggregation, the spontaneous organization of initially scattered convection into isolated convective clusters despite spatially homogeneous boundary conditions and forcing, was first recognized and studied in idealized numerical simulations. While there is a rich history of observational work on convective clustering and organization, there have been only a few studies that have analyzed observations to look specifically for processes related to self-aggregation in models. Here we review observational work in both of these categories and motivate the need for more of this work. We acknowledge that self-aggregation may appear to be far-removed from observed convective organization in terms of time scales, initial conditions, initiation processes, and mean state extremes, but we argue that these differences vary greatly across the diverse range of model simulations in the literature and that these comparisons are already offering important insights into real tropical phenomena. Some preliminary new findings are presented, including results showing that a self-aggregation simulation with square geometry has too broad distribution of humidity and is too dry in the driest regions when compared with radiosonde records from Nauru, while an elongated channel simulation has realistic representations of atmospheric humidity and its variability. We discuss recent work increasing our understanding of how organized convection and climate change may interact, and how model discrepancies related to this question are prompting interest in observational comparisons. We also propose possible future directions for observational work related to convective aggregation, including novel satellite approaches and a ground-based observational network.

  9. Formation of charge separated state P+OA- and triplet state 3P at low temperature in Rhodobacter sphaeroides (R-26) reaction centers in which bacteriopheophytin a is replaced by plant pheophytin a.

    Science.gov (United States)

    Shkuropatov Aya; Proskuryakov, I I; Shkuropatova, V A; Zvereva, M G; Shuvalov, V A

    1994-09-05

    Low temperature optical and photochemical properties of Rhodobacter sphaeroides (R-26) reaction centers, in which bacteriopheophytin a has been replaced by plant pheophytin a, are reported. Modified reaction centers preserve the ability for photoinduced electron transfer from the primary electron donor P to the primary quinone acceptor QA at 80K. The triplet state ESR signal of modified reaction centers with prereduced QA at 10K shows an electron spin polarization pattern and ZFS parameters analogous to those for the triplet state 3P in non-treated reaction centers. It was found that at low temperature both P+QA- and 3P states are formed via a precursor radical pair P+I- in which I is the introduced plant pheophytin molecule. This shows that acceptor systems of bacterial and plant (photosystem II) reaction centers are mutually replacable in structural and functional aspects.

  10. Retention Benefit Based Intelligent Cache Replacement

    Institute of Scientific and Technical Information of China (English)

    李凌达; 陆俊林; 程旭

    2014-01-01

    The performance loss resulting from different cache misses is variable in modern systems for two reasons: 1) memory access latency is not uniform, and 2) the latency toleration ability of processor cores varies across different misses. Compared with parallel misses and store misses, isolated fetch and load misses are more costly. The variation of cache miss penalty suggests that the cache replacement policy should take it into account. To that end, first, we propose the notion of retention benefit. Retention benefits can evaluate not only the increment of processor stall cycles on cache misses, but also the reduction of processor stall cycles due to cache hits. Then, we propose Retention Benefit Based Replacement (RBR) which aims to maximize the aggregate retention benefits of blocks reserved in the cache. RBR keeps track of the total retention benefit for each block in the cache, and it preferentially evicts the block with the minimum total retention benefit on replacement. The evaluation shows that RBR can improve cache performance significantly in both single-core and multi-core environment while requiring a low storage overhead. It also outperforms other state-of-the-art techniques.

  11. Replacing America's Job Bank

    Science.gov (United States)

    Vollman, Jim

    2009-01-01

    The Job Central National Labor Exchange (www.jobcentral.com) has become the effective replacement for America's Job Bank with state workforce agencies and, increasingly, with community colleges throughout the country. The American Association of Community Colleges (AACC) has formed a partnership with Job Central to promote its use throughout the…

  12. Replacing America's Job Bank

    Science.gov (United States)

    Vollman, Jim

    2009-01-01

    The Job Central National Labor Exchange (www.jobcentral.com) has become the effective replacement for America's Job Bank with state workforce agencies and, increasingly, with community colleges throughout the country. The American Association of Community Colleges (AACC) has formed a partnership with Job Central to promote its use throughout the…

  13. A Changing Number of Alternative States in the Boreal Biome: Reproducibility Risks of Replacing Remote Sensing Products.

    Science.gov (United States)

    Xu, Chi; Holmgren, Milena; Van Nes, Egbert H; Hirota, Marina; Chapin, F Stuart; Scheffer, Marten

    2015-01-01

    Publicly available remote sensing products have boosted science in many ways. The openness of these data sources suggests high reproducibility. However, as we show here, results may be specific to versions of the data products that can become unavailable as new versions are posted. We focus on remotely-sensed tree cover. Recent studies have used this public resource to detect multi-modality in tree cover in the tropical and boreal biomes. Such patterns suggest alternative stable states separated by critical tipping points. This has important implications for the potential response of these ecosystems to global climate change. For the boreal region, four distinct ecosystem states (i.e., treeless, sparse and dense woodland, and boreal forest) were previously identified by using the Collection 3 data of MODIS Vegetation Continuous Fields (VCF). Since then, the MODIS VCF product has been updated to Collection 5; and a Landsat VCF product of global tree cover at a fine spatial resolution of 30 meters has been developed. Here we compare these different remote-sensing products of tree cover to show that identification of alternative stable states in the boreal biome partly depends on the data source used. The updated MODIS data and the newer Landsat data consistently demonstrate three distinct modes around similar tree-cover values. Our analysis suggests that the boreal region has three modes: one sparsely vegetated state (treeless), one distinct 'savanna-like' state and one forest state, which could be alternative stable states. Our analysis illustrates that qualitative outcomes of studies may change fundamentally as new versions of remote sensing products are used. Scientific reproducibility thus requires that old versions remain publicly available.

  14. A Changing Number of Alternative States in the Boreal Biome: Reproducibility Risks of Replacing Remote Sensing Products.

    Directory of Open Access Journals (Sweden)

    Chi Xu

    Full Text Available Publicly available remote sensing products have boosted science in many ways. The openness of these data sources suggests high reproducibility. However, as we show here, results may be specific to versions of the data products that can become unavailable as new versions are posted. We focus on remotely-sensed tree cover. Recent studies have used this public resource to detect multi-modality in tree cover in the tropical and boreal biomes. Such patterns suggest alternative stable states separated by critical tipping points. This has important implications for the potential response of these ecosystems to global climate change. For the boreal region, four distinct ecosystem states (i.e., treeless, sparse and dense woodland, and boreal forest were previously identified by using the Collection 3 data of MODIS Vegetation Continuous Fields (VCF. Since then, the MODIS VCF product has been updated to Collection 5; and a Landsat VCF product of global tree cover at a fine spatial resolution of 30 meters has been developed. Here we compare these different remote-sensing products of tree cover to show that identification of alternative stable states in the boreal biome partly depends on the data source used. The updated MODIS data and the newer Landsat data consistently demonstrate three distinct modes around similar tree-cover values. Our analysis suggests that the boreal region has three modes: one sparsely vegetated state (treeless, one distinct 'savanna-like' state and one forest state, which could be alternative stable states. Our analysis illustrates that qualitative outcomes of studies may change fundamentally as new versions of remote sensing products are used. Scientific reproducibility thus requires that old versions remain publicly available.

  15. Waves and aggregation patterns in myxobacteria

    Science.gov (United States)

    Igoshin, Oleg A.; Welch, Roy; Kaiser, Dale; Oster, George

    2004-03-01

    Under starvation conditions, a population of myxobacteria aggregates to build a fruiting body whose shape is species-specific and within which the cells sporulate. Early in this process, cells often pass through a "ripple phase" characterized by traveling linear, concentric, and spiral waves. These waves are different from the waves observed during slime mold aggregation that depend on diffusible morphogens, because myxobacteria communicate by direct contact. The difference is most dramatic when waves collide: rather than annihilating one another, myxobacterial waves appear to pass through one another unchanged. Under certain conditions, the spacing and location of the nascent fruiting bodies is determined by the wavelength and pattern of the waves. Later in fruiting body development, waves are replaced by streams of cells that circulate around small initial aggregates enlarging and rounding them. Still later, pairs of motile aggregates coalesce to form larger aggregates that develop into fruiting bodies. Here we present a mathematical model that quantitatively explains these wave and aggregation phenomena.

  16. Dye Aggregation in Ink Jet

    Institute of Scientific and Technical Information of China (English)

    Thomas Paul; Sarfraz Hussain

    2004-01-01

    Dye aggregation has long been recognised as a key factor in performance, and this is no less so in ink jet applications. The aggregation state was shown to be important in many different areas ranging from the use of dyes in photodynamic therapies all the way to colorants for dying of fabrics. Therefore different methods to investigate dye association qualitatively and quantitatively were developed. A simple procedure to study aggregation could be a useful tool to characterise dyes for ink jet printing. It is critically reviewed the methods used to study dye aggregation, and discussed some of the main conclusions. This will be illustrated by examples of ink jet dye aggregation and its study in aqueous and ink systems. The results are used to correlate the solution behaviour of dyes with their print performance.

  17. CURRENT STATE OF AUTOMOTIVE LIGHTING EQUIPMENT WITH NON-REPLACEABLE LIGHT SOURCES ON BASIS OF LIGHT-EMITTING DIODE TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    S. Sernov

    2012-01-01

    Full Text Available The paper contains information on the current state of automotive lighting equipment. Different designs of automotive lighting devices, their merits and demerits are described in the paper. The paper includes a substantiation of expediency of developing light-emitting diode lighting and proposes recommendations about optimization of their design.

  18. [Estrogen replacement].

    Science.gov (United States)

    Søgaard, A J; Berntsen, G K; Magnus, J H; Tollan, A

    1998-02-10

    Recent research on long-term postmenopausal hormone replacement therapy (HRT) indicates a positive effect on both total mortality and morbidity. This has raised the question of widespread preventive long-term use of HRT. Possible side-effects and ideological issues related to preventive HRT have led to debate and uncertainty among health professionals, in the media, and in the population at large. In order to evaluate the level of knowledge about and attitudes towards HRT, a randomly selected group of 737 Norwegian women aged 16-79 was interviewed by the Central Bureau of Statistics. One in three women had received information about HRT in the last two years, mainly through weekly magazines and physicians. The proportion who answered the questions on knowledge correctly varied from 36% to 47%. Those who had been given information by a physician possessed accurate knowledge, had more positive attitudes towards HRT and were more willing to use HRT than women who had reviewed information through other channels. Women with a higher level of education were better informed and more knowledgeable than others, but were nevertheless more reluctant to use HRT than those who were less educated. The limited number of women who actually receive information on HRT, the low level of knowledge and the ambivalent attitudes toward HRT are a major challenge to the public health service.

  19. A unified single-event microkinetic model for alkane hydroconversion in different aggregation states on Pt/H-USY-zeolites.

    Science.gov (United States)

    Laxmi Narasimhan, C S; Thybaut, Joris W; Martens, Johan A; Jacobs, Pierre A; Denayer, Joeri F; Marin, Guy B

    2006-04-06

    A single-event microkinetic model for the catalytic hydroconversion of hydrocarbons on Pt/H-US-Y bifunctional zeolite catalysts developed for low-pressure vapor phase conditions was extended to cover high-pressure vapor phase and liquid phase conditions. The effect of the density of the bulk hydrocarbon phase on the physisorption as well as on the protonation steps of the reaction network was accounted for explicitly and can be interpreted in terms of "compression" of the hydrocarbon sorbate inside the zeolite pores and "solvation" of the catalyst framework by the dense bulk hydrocarbon phase. The bulk phase density effect on the physisorbed state is described via a single excess free enthalpy of physisorption. A dense bulk hydrocarbon phase destabilizes the sorbate molecules inside the catalyst pores. An expression of the excess free enthalpy of physisorption involving the fugacity coefficient and a zeolite dependent factor allows description of physisorption data. Typical excess free enthalpy values are in the range 1.5-5.1 kJ mol(-1) increasing with carbon number in the series of C5-C16 alkanes. At high-pressure vapor phase and liquid phase conditions, the excess standard protonation enthalpy is estimated at -7.8 kJ mol(-1) leading to relatively more stable carbenium ions at dense bulk phase conditions. As a result of the excess physisorption and protonation properties, the lightest hydrocarbons in mixtures are more competitive at dense phase conditions and their conversion is enhanced compared to low-density conditions.

  20. Current state of the rearing of replacement young-of-the-year Acipenseriformes in the conditions of the southern Ukraine

    Directory of Open Access Journals (Sweden)

    Ye. Alkhimov

    2017-03-01

    Full Text Available Purpose. Examine and analyze the current state of storage fingerlings acipenseriformes cultivation, including sturgeon and paddlefish, in terms of industrial-experimental Dnieper sturgeon fish-growing factory located in the southern Ukraine. Methodology. The problems were solved by the conventional methods in hydrochemistry, hydrobiology and fish farming. The results were processed using statistical methods of the data processing and analysis which suggest it reliable. Findigs. The research has established that physical and chemical parameters of water in farms' ponds answered the operating pond fishery regulations. The existing level of natural forage base elements can be considered satisfacting for the growing storage material. The best development of zooplankton in the application of polyculture acipenseriformes should be noted. The monoculture benefit was observed in the most fisheries indicators for certain types. Sturgeon fish productivity advantage in terms of polyculture is the evidence of positive mutual influences among the reservoir consumers of different trophic levels. In terms of polyculture the significant benefit of total fish productivity indicator was observed. It clearly points to the prospects of the measure in terms of substantial efficiency of pond areas for growing storage fingerlings. Results of acipenseriformes growing in mono- and polyculture clearly favor the polyculture, which could be used in breeding practice. Scientific Originality. In specific conditions of the southern Ukraine the influence of environmental and technological conditions for growing storage fingerlings acipenseriformes fish (sturgeon and paddlefish was investigated for the first time. In terms of mono- and polyculture cultivation storage acipenseriformes fish material was firstly explored. Practical Value. The results of cultivation can be used in breeding practice as the norm of the environmental situation evaluation in the ponds. Growing storage

  1. A strategic approach for direct recovery and stabilization of Fusarium sp. ICT SAC1 cutinase from solid state fermented broth by carrier free cross-linked enzyme aggregates.

    Science.gov (United States)

    Chaudhari, Sandeep A; Singhal, Rekha S

    2017-05-01

    The major hurdles in commercial exploitation of cutinase (having both esterolytic and lipolytic activities) with potent industrial applications are its high production cost, operational instability and reusability. Although commercially available in immobilized form, its immobilization process (synthesis of support/carrier) makes it expensive. Herein we tried to address multiple issues of production cost, stability, and reusability, associated with cutinase. Waste watermelon rinds, an agroindustrial waste was considered as a cheap support for solid state fermentation (SSF) for cutinase production by newly isolated Fusarium sp. ICT SAC1. Subsequently, carrier free cross-linked enzyme aggregates of cutinase (cut-CLEA) directly from the SSF crude broth were developed. All the process variables affecting CLEA formation along with the different additives were evaluated. It was found that 50% (w/v) of ammonium sulphate, 125μmol of glutaraldehyde, cross-linking for 1h at 30°C and broth pH of 7.0, yielded 58.12% activity recovery. All other additives (hexane, butyric acid, sodium dodecyl sulphate, Trition-X 100, Tween-20, BSA) evaluated presented negative results to our hypothesis. Kinetics and morphology studies confirmed the diffusive nature of cut-CLEA and BSA cut-CLEA. Developed CLEA showed better thermal, solvent, detergent and storage stability, making it more elegant and efficient for industrial biocatalytic process.

  2. Recycled Concrete as Aggregate for Structural Concrete Production

    National Research Council Canada - National Science Library

    Malešev, Mirjana; Radonjanin, Vlastimir; Marinković, Snežana

    2010-01-01

    A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper...

  3. Pore structure of natural and regenerated soil aggregates

    DEFF Research Database (Denmark)

    Naveed, Muhammad; Arthur, Emmanuel; de Jonge, Lis Wollesen

    2014-01-01

    of the soil type and organic matter amendment, and was vastly different from the state of natural aggregates. Aggregate porosity (> 30 Hm) was observed to be a good predictor for the mechanical properties of aggregates. In general, natural aggregates were stronger than lysimeter aggregates.......Quantitative characterization of aggregate pore structure can reveal the evolution of aggregates under different land use and management practices and their effects on soil processes and functions. Advances in X-ray Computed Tomography (CT) provide powerful means to conduct such characterization....... This study examined aggregate pore structure of three differently managed same textured Danish soils (mixed forage cropping, MFC; mixed cash cropping, MCC; cereal cash cropping, CCC) for (i) natural aggregates, and (ii) aggregates regenerated after 20 months of incubation. In total, 27 aggregates (8-16 mm...

  4. Cyclosporine A enhances platelet aggregation.

    Science.gov (United States)

    Grace, A A; Barradas, M A; Mikhailidis, D P; Jeremy, J Y; Moorhead, J F; Sweny, P; Dandona, P

    1987-12-01

    In view of the reported increase in thromboembolic episodes following cyclosporine A (CyA) therapy, the effect of this drug on platelet aggregation and thromboxane A2 release was investigated. The addition of CyA, at therapeutic concentrations to platelet rich plasma from normal subjects in vitro was found to increase aggregation in response to adrenaline, collagen and ADP. Ingestion of CyA by healthy volunteers was also associated with enhanced platelet aggregation. The CyA-mediated enhancement of aggregation was further enhanced by the addition in vitro of therapeutic concentrations of heparin. Platelets from renal allograft recipients treated with CyA also showed hyperaggregability and increased thromboxane A2 release, which were most marked at "peak" plasma CyA concentration and less so at "trough" concentrations. Platelet hyperaggregability in renal allograft patients on long-term CyA therapy tended to revert towards normal following the replacement of CyA with azathioprine. Hypertensive patients with renal allografts on nifedipine therapy had normal platelet function and thromboxane release in spite of CyA therapy. These observations suggest that CyA-mediated platelet activation may contribute to the pathogenesis of the thromboembolic phenomena associated with the use of this drug. The increased release of thromboxane A2 (a vasoconstrictor) may also play a role in mediating CyA-related nephrotoxicity.

  5. Aggregate and Mineral Resources, This data set consists of mineral deposit areas (KMDAs) for locatable minerals., Published in 1993, Arizona State Land Department.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Aggregate and Mineral Resources dataset as of 1993. It is described as 'This data set consists of mineral deposit areas (KMDAs) for locatable minerals.'. Data...

  6. Effect of Chipped Rubber Aggregates on Performance of Concrete

    Directory of Open Access Journals (Sweden)

    Sunil N. Shah

    2014-12-01

    Full Text Available Due to rapid growth in automobile industry, use of tyre increases day to day and there is no reuse of the same to decrease the environmental pollution. The decomposition and disposing of waste tyre rubber is harmful to environment. This research reflects the reuse of waste tyre rubber into concrete after observing their properties. In that experimental work chipped rubber aggregates replaced to the natural coarse aggregates by varying percentage of 3, 6, 9 and 12 with comparison of 0% replacement. Silica fume is replaced in 10% with cement for improving the bond properties between cement paste and rubber. In evaluation, test has been carried out to determine the properties of concrete such as workability, unit weight, flexural strength and split tensile strength. The workability of fresh concrete is observed with the help of compaction factor test. From the test of compaction factor, workability is decrease with increasing percentage of chipped rubber. The specific gravity of chipped rubber aggregates is lower as compared to natural aggregates therefore decrease the unit weight of rubber mix concrete. Increasing chipped rubber aggregates as partial replacement into concrete reduces compressive strength. So these can use in non-primary structural applications of medium to low strength requirements. The overall results of study show that it is possible to use recycled rubber tyre aggregates in concrete construction as partial replacement to natural coarse aggregates.

  7. Natural Radionuclide Contents in Raw Materials and the Aggregate Finished Product from Dangote Cement Plc, Obajana, Kogi State, North Central Nigeria

    Directory of Open Access Journals (Sweden)

    J.O. Ajayi

    2012-11-01

    Full Text Available Assessment of gamma ray activity in raw materials and the end product in Dangote Cement from Dangote Cement Plc, Obajana and Kogi State has been investigated in this study. Gamma ray spectrometry that possesses scintillation detector was used to analyze the samples collected from the company. Samples collected as raw materials are limestone, clay, gypsum and laterite and cement as finished product. The 40K, 238U, 232Th activity concentration were detected. The concentration of 40K range from 4649±366 to 0±65 Bq/Kg with highest value in limestone and lowest in laterite. The 238U concentration is highest in gypsum range from 696±233 to 41±27 Bq/Kg in laterite. 232Th activity is below detectable limit in all the raw materials but it has activity concentration of 40±26 Bq/Kg in the finished product which may be traceable to the fact that some finished additives are present which are not in the basic raw materials of this cement under investigation. It is concluded that the natural radionuclide measured for 40K, 238U and 232Th has mean activities of 2189.75±219.5, 331.25±132.25 and 0±31 Bq/Kg respectively, while its corresponding mean absorbed dose rate in air at 1 m above the ground was calculated to be 235.61 nGy/h or 2.064 mSv/y and the aggregate finished product (cement has absorbed dose rate of 342.22 nGy/h and an effective dose equivalent of 2.998 mSv/y. The calculated absorbed doses in nGy/h and mSv/y shows that Dangote cement under consideration has higher activities of the isotopes than the permissible level suggested by ICRP (80 nGy/h or 0.7 mSv/y

  8. Study on Mechanical Properties of Concrete Using Plastic Waste as an Aggregate

    Science.gov (United States)

    Jaivignesh, B.; Sofi, A.

    2017-07-01

    Disposal of large quantity of plastic causes land, water and air pollution etc.., so a study is conducted to recycle the plastic in concrete. This work investigates about the replacement of natural aggregate with non-biodegradable plastic aggregate made up of mixed plastic waste in concrete. Several tests are conducted such as compressive strength of cube, split tensile strength of cylinder, flexural strength test of prism to identify the properties and behavior of concrete using plastic aggregate. Replacement of fine aggregate weight by 10%, 15%, 20% with Plastic fine (PF) aggregate and for each replacement of fine aggregate 15%, 20%, 25% of coarse aggregate replacement also conducted with Plastic Coarse(PC) aggregate. In literatures reported that the addition of plastic aggregate in concrete causes the reduction of strength in concrete due to poor bonding between concrete and plastic aggregate, so addition of 0.3% of steel fiber by weight of cement in concrete is done to improve the concrete strength. Totally 60 cubes, 60 cylinders and 40 prisms are casted to identify the compressive strength, split tensile strength and flexural strength respectively. Casted specimens are tested at 7 and 28 days. The identified results from concrete using plastic aggregate are compared with conventional concrete. Result shows that reduction in mechanical properties of plastic aggregate added concrete. This reduction in strength is mainly due to poor bond strength between cement and plastic aggregate.

  9. OARSI/OMERACT initiative to define states of severity and indication for joint replacement in hip and knee osteoarthritis. An OMERACT 10 Special Interest Group

    DEFF Research Database (Denmark)

    Gossec, Laure; Paternotte, Simon; Bingham, Clifton O;

    2011-01-01

    To define pain and physical function cutpoints that would, coupled with structural severity, define a surrogate measure of "need for joint replacement surgery," for use as an outcome measure for potential structure-modifying interventions for osteoarthritis (OA)....

  10. SHAPE CHARACTERIZATION OF CONCRETE AGGREGATE

    Directory of Open Access Journals (Sweden)

    Jing Hu

    2011-05-01

    Full Text Available As a composite material, the performance of concrete materials can be expected to depend on the properties of the interfaces between its two major components, aggregate and cement paste. The microstructure at the interfacial transition zone (ITZ is assumed to be different from the bulk material. In general, properties of conventional concrete have been found favoured by optimum packing density of the aggregate. Particle size is a common denominator in such studies. Size segregation in the ITZ among the binder particles in the fresh state, observed in simulation studies by concurrent algorithm-based SPACE system, additionally governs density as well as physical bonding capacity inside these shell-like zones around aggregate particles. These characteristics have been demonstrated qualitatively pertaining also after maturation of the concrete. Such properties of the ITZs have direct impact on composite properties. Despite experimental approaches revealed effects of aggregate grain shape on different features of material structure (among which density, and as a consequence on mechanical properties, it is still an underrated factor in laboratory studies, probably due to the general feeling that a suitable methodology for shape characterization is not available. A scientific argument hindering progress is the interconnected nature of size and shape. Presently, a practical problem preventing shape effects to be emphasized is the limitation of most computer simulation systems in concrete technology to spherical particles. New developments at Delft University of Technology will make it possible in the near future to generate jammed states, or other high-density fresh particle mixtures of non-spherical particles, which thereupon can be subjected to hydration algorithms. This paper will sketch the outlines of a methodological approach for shape assessment of loose (non-embedded aggregate grains, and demonstrate its use for two types of aggregate, allowing

  11. Distinguishing aggregate formation and aggregate clearance using cell based assays

    NARCIS (Netherlands)

    E. Eenjes, E.; J.M. Dragich; H. Kampinga (Harm); A. Yamamoto, A.

    2016-01-01

    textabstractThe accumulation of ubiquitinated proteinaceous inclusions represents a complex process, reflecting the disequilibrium between aggregate formation and aggregate clearance. Although decreasing aggregate formation or augmenting aggregate clearance will ultimately lead to diminished aggrega

  12. Performance of Light-Weight Concrete with Plastic Aggregate

    Directory of Open Access Journals (Sweden)

    Anju Ramesan

    2015-08-01

    Full Text Available This study is intended to explore the suitability of recycled plastics (high density polyethylene as coarse aggregate in concrete by conducting various tests like workability by slump test, compressive strength of cube and cylinder, splitting tensile strength test of cylinder, flexural strength of R.C.C as well as P.CC. beams to determine the properties and behaviour in concrete. Effect of replacement of coarse aggregate with various percentages (0% to 40% of plastic aggregate on behaviour of concrete was experimentally investigated and the optimum replacement of coarse aggregate was found out. The results showed that the addition of plastic aggregate to the concrete mixture improved the properties of the resultant mix.

  13. Impact of income-detection technology and other factors on aggregate income tax evasion:the case of the United States

    Directory of Open Access Journals (Sweden)

    Richard J. Cebula

    2001-12-01

    Full Text Available This study empirically investigates the impact of improving income-detectiontechnology, as well as a variety of other factors, on aggregate income taxevasion. The study focuses on the U.S., using available data for the 1975-97 period. The empirical findings indicate that improving income-detection technology appears to have significantly reduced the degree of aggregate income-tax evasion in theU.S. over time. In addition, the estimates indicate that federal income tax evasionappears to be an increasing function not only of the federal personal income tax rate but also of the public's dissatisfaction with government. Furthermore, income taxevasion appears to be a decreasing function both of penalties imposed by the IRS on unpaid taxes and IRS audit rates.

  14. Impact of Bulk Aggregation on the Electronic Structure of Streptocyanines: Implications for the Solid-State Nonlinear Optical Properties and All-Optical Switching Applications

    KAUST Repository

    Gieseking, Rebecca L.

    2014-10-16

    Polymethine dyes in dilute solutions show many of the electronic and optical properties required for all-optical switching applications. However, in the form of thin films, their aggregation and interactions with counterions do generally strongly limit their utility. Here, we present a theoretical approach combining molecular-dynamics simulations and quantum-chemical calculations to describe the bulk molecular packing of streptocyanines (taken as representative of simple polymethines) with counterions of different hardness (Cl and BPh4 ) and understand the impact on the optical properties. The accuracy of the force field we use is verified by reproducing experimental crystal parameters as well as the configurations of polymethine/counterion complexes obtained from electronic-structure calculations. The aggregation characteristics can be understood in terms of both polymethinecounterion and polymethinepolymethine interactions. The counterions are found to localize near one end of the streptocyanine backbones, and the streptocyanines form a broad range of aggregates with significant electronic couplings between neighboring molecules. As a consequence, the linear and nonlinear optical properties are substantially modified in the bulk. By providing an understanding of the relationship between the molecular interactions and the bulk optical properties, our results point to a clear strategy for designing polymethine and counterion molecular structures and optimizing the materials properties for all-optical switching applications.

  15. Replacement policies for dairy cows

    DEFF Research Database (Denmark)

    Nielsen, Lars Relund

    In a recent paper a hierarchical Markov decision processes (MDP) with finite state and action space was formulated for the dairy cow replacement problem with stage lengths of 1 d. Bayesian updating was used to predict the performance of each cow in the herd and economic decisions were based...

  16. Shoulder Joint Replacement

    Science.gov (United States)

    ... Shoulder Replacement Options Shoulder replacement surgery is highly technical. It should be performed by a surgical team ... area and will meet a doctor from the anesthesia department. You, your anesthesiologist, and your surgeon will ...

  17. Partial knee replacement - slideshow

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/presentations/100225.htm Partial knee replacement - series—Normal anatomy To use the sharing ... A.M. Editorial team. Related MedlinePlus Health Topics Knee Replacement A.D.A.M., Inc. is accredited ...

  18. Recycled Concrete as Aggregate for Structural Concrete Production

    Directory of Open Access Journals (Sweden)

    Mirjana Malešev

    2010-04-01

    Full Text Available A comparative analysis of the experimental results of the properties of fresh and hardened concrete with different replacement ratios of natural with recycled coarse aggregate is presented in the paper. Recycled aggregate was made by crushing the waste concrete of laboratory test cubes and precast concrete columns. Three types of concrete mixtures were tested: concrete made entirely with natural aggregate (NAC as a control concrete and two types of concrete made with natural fine and recycled coarse aggregate (50% and 100% replacement of coarse recycled aggregate. Ninety-nine specimens were made for the testing of the basic properties of hardened concrete. Load testing of reinforced concrete beams made of the investigated concrete types is also presented in the paper. Regardless of the replacement ratio, recycled aggregate concrete (RAC had a satisfactory performance, which did not differ significantly from the performance of control concrete in this experimental research. However, for this to be fulfilled, it is necessary to use quality recycled concrete coarse aggregate and to follow the specific rules for design and production of this new concrete type.

  19. Ageing and hypoxia cause protein aggregation in mitochondria.

    Science.gov (United States)

    Kaufman, Daniel M; Wu, Xia; Scott, Barbara A; Itani, Omar A; Van Gilst, Marc R; Bruce, James E; Michael Crowder, C

    2017-10-01

    Aggregation of cytosolic proteins is a pathological finding in disease states, including ageing and neurodegenerative diseases. We have previously reported that hypoxia induces protein misfolding in Caenorhabditis elegans mitochondria, and electron micrographs suggested protein aggregates. Here, we seek to determine whether mitochondrial proteins actually aggregate after hypoxia and other cellular stresses. To enrich for mitochondrial proteins that might aggregate, we performed a proteomics analysis on purified C. elegans mitochondria to identify relatively insoluble proteins under normal conditions (110 proteins identified) or after sublethal hypoxia (65 proteins). A GFP-tagged mitochondrial protein (UCR-11 - a complex III electron transport chain protein) in the normally insoluble set was found to form widespread aggregates in mitochondria after hypoxia. Five other GFP-tagged mitochondrial proteins in the normally insoluble set similarly form hypoxia-induced aggregates. Two GFP-tagged mitochondrial proteins from the soluble set as well as a mitochondrial-targeted GFP did not form aggregates. Ageing also resulted in aggregates. The number of hypoxia-induced aggregates was regulated by the mitochondrial unfolded protein response (UPRmt) master transcriptional regulator ATFS-1, which has been shown to be hypoxia protective. An atfs-1(loss-of-function) mutant and RNAi construct reduced the number of aggregates while an atfs-1(gain-of-function) mutant increased aggregates. Our work demonstrates that mitochondrial protein aggregation occurs with hypoxic injury and ageing in C. elegans. The UPRmt regulates aggregation and may protect from hypoxia by promoting aggregation of misfolded proteins.

  20. Overview of studies on the effect of recycled aggregates sourced from tested cylinders on concrete material and structural properties

    Directory of Open Access Journals (Sweden)

    Bilal Hamad

    2017-01-01

    Full Text Available The paper presents an overview of a two-phase research program that was designed at the American University of Beirut (AUB to investigate the effect of replacing different percentages of natural coarse aggregates (NCA with recycled coarse aggregates (RCA on the properties of the produced concrete. The source of RCA was tested cylinders in batching plants which would help recycling and reusing portion of the waste products of the concrete industry. In the first phase, the fresh and hardened mechanical properties of the produced concrete mix were investigated. The variables were the concrete strength (28 or 60 MPa and the percentage replacement of NCA with RCA from crushed tested cylinders [0 (control, 20, 40, 60, 80, or 100%. Normal strength tested cylinders were used as source of the recycled aggregates for the normal strength concrete (NSC mix and high strength tested cylinders were used for the high strength concrete (HSC mix. Tests included plastic state slump and hardened state mechanical properties including cylinder compressive strength, cylinder splitting tensile strength, modulus of elasticity, and standard beams flexural strength. The results indicated no significant effect on the slump and around 10% average reduction in the hardened mechanical properties for both investigated levels of concrete compressive strength. In the second phase, the structural behavior of normal strength concrete (NSC reinforced concrete beams prepared by replacing different percentages of NCA with RCA from tested concrete cylinders was studied. For each of three modes of failure (flexural, shear, or bond splitting, three beams with different percentages replacement [0 (control, 40, or 100 percent] were tested. One replicate was prepared for each beam to validate the test results. Results indicated no significant difference in the ultimate load reached or load-deflection behavior that could be related to the percentage replacement of NCA with RCA.

  1. Aggregations in Flatworms.

    Science.gov (United States)

    Liffen, C. L.; Hunter, M.

    1980-01-01

    Described is a school project to investigate aggregations in flatworms which may be influenced by light intensity, temperature, and some form of chemical stimulus released by already aggregating flatworms. Such investigations could be adopted to suit many educational levels of science laboratory activities. (DS)

  2. Platelet activation and aggregation

    DEFF Research Database (Denmark)

    Jensen, Maria Sander; Larsen, O H; Christiansen, Kirsten

    2013-01-01

    This study introduces a new laboratory model of whole blood platelet aggregation stimulated by endogenously generated thrombin, and explores this aspect in haemophilia A in which impaired thrombin generation is a major hallmark. The method was established to measure platelet aggregation initiated...

  3. Cardiovascular risk factor and familial aggregation of blood pressure with respect to anthropometric variables in a scheduled caste population in Punjab, a North Indian state.

    Science.gov (United States)

    Badaruddoza; Kumar, Raman

    2009-06-01

    Based on anthropometric data, this study aims to detect cardiovascular risk factor and familial aggregation of blood pressure in a specific community in India. A total of 1096 adult individuals, constituting 350 families in a scheduled caste community in Punjab, India, was surveyed for blood pressure, pulse rate, pulse pressure and fifteen anthropometric measurements. Estimates of correlation among blood pressure phenotypes with other significant variables and stepwise multiple regression analysis have been carried out for both offspring and parent generations. The hypothesis for common household effects was examined by likelihood ratio tests. Almost all anthropometric variables were found to be significant with blood pressure between both generations. The percent of variance for the regression (R2) was found to be higher for the offspring generation than for the parent one. The results suggest that despite of genetic effects, common household environment for many anthropometric measurements is a significant determinant of blood pressure. The data indicate a strong familial aggregation of blood pressure and anthropometric measurements should be a useful tool for screening cardiovascular risk factor with elevated blood pressure.

  4. Aggregate breakup in a contracting nozzle.

    Science.gov (United States)

    Soos, Miroslav; Ehrl, Lyonel; Bäbler, Matthäus U; Morbidelli, Massimo

    2010-01-05

    The breakup of dense aggregates in an extensional flow was investigated experimentally. The flow was realized by pumping the suspension containing the aggregates through a contracting nozzle. Variation of the cluster mass distribution during the breakage process was measured by small-angle light scattering. Because of the large size of primary particles and the dense aggregate structure image analysis was used to determine the shape and structure of the produced fragments. It was found, that neither aggregate structure, characterized by a fractal dimension d(f) = 2.7, nor shape, characterized by an average aspect ratio equal to 1.5, was affected by breakage. Several passes through the nozzle were required to reach the steady state. This is explained by the radial variation of the hydrodynamic stresses at the nozzle entrance, characterized through computational fluid dynamics, which implies that only the fraction of aggregates whose strength is smaller than the local hydrodynamic stress is broken during one pass through the nozzle. Scaling of the steady-state aggregate size as a function of the hydrodynamic stress was used to determine the aggregate strength.

  5. Aggregates from mineral wastes

    Directory of Open Access Journals (Sweden)

    Baic Ireneusz

    2016-01-01

    Full Text Available The problem concerning the growing demand for natural aggregates and the need to limit costs, including transportation from remote deposits, cause the increase in growth of interest in aggregates from mineral wastes as well as in technologies of their production and recovery. The paper presents the issue related to the group of aggregates other than natural. A common name is proposed for such material: “alternative aggregates”. The name seems to be fully justified due to adequacy of this term because of this raw materials origin and role, in comparison to the meaning of natural aggregates based on gravel and sand as well as crushed stones. The paper presents characteristics of the market and basic application of aggregates produced from mineral wastes, generated in the mining, power and metallurgical industries as well as material from demolished objects.

  6. Towards Better Understanding of Concrete Containing Recycled Concrete Aggregate

    Directory of Open Access Journals (Sweden)

    Hisham Qasrawi

    2013-01-01

    Full Text Available The effect of using recycled concrete aggregates (RCA on the basic properties of normal concrete is studied. First, recycled aggregate properties have been determined and compared to those of normal aggregates. Except for absorption, there was not a significant difference between the two. Later, recycled aggregates were introduced in concrete mixes. In these mixes, natural coarse aggregate was partly or totally replaced by recycled aggregates. Results show that the use of recycled aggregates has an adverse effect on the workability and air content of fresh concrete. Depending on the water/cement ratio and on the percent of the normal aggregate replaced by RCA, the concrete strength is reduced by 5% to 25%, while the tensile strength is reduced by 4% to 14%. All results are compared with previous research. As new in this research, the paper introduces a simple formula for the prediction of the modulus of elasticity of RCA concrete. Furthermore, the paper shows the variation of the air content of RAC.

  7. Marine Synechococcus Aggregation

    Science.gov (United States)

    Neuer, S.; Deng, W.; Cruz, B. N.; Monks, L.

    2016-02-01

    Cyanobacteria are considered to play an important role in the oceanic biological carbon pump, especially in oligotrophic regions. But as single cells are too small to sink, their carbon export has to be mediated by aggregate formation and possible consumption by zooplankton producing sinking fecal pellets. Here we report results on the aggregation of the ubiquitous marine pico-cyanobacterium Synechococcus as a model organism. We first investigated the mechanism behind such aggregation by studying the potential role of transparent exopolymeric particles (TEP) and the effects of nutrient (nitrogen or phosphorus) limitation on the TEP production and aggregate formation of these pico-cyanobacteria. We further studied the aggregation and subsequent settling in roller tanks and investigated the effects of the clays kaolinite and bentonite in a series of concentrations. Our results show that despite of the lowered growth rates, Synechococcus in nutrient limited cultures had larger cell-normalized TEP production, formed a greater volume of aggregates, and resulted in higher settling velocities compared to results from replete cultures. In addition, we found that despite their small size and lack of natural ballasting minerals, Synechococcus cells could still form aggregates and sink at measureable velocities in seawater. Clay minerals increased the number and reduced the size of aggregates, and their ballasting effects increased the sinking velocity and carbon export potential of aggregates. In comparison with the Synechococcus, we will also present results of the aggregation of the pico-cyanobacterium Prochlorococcus in roller tanks. These results contribute to our understanding in the physiology of marine Synechococcus as well as their role in the ecology and biogeochemistry in oligotrophic oceans.

  8. Aggregation of red blood cells in patients with Gaucher disease.

    Science.gov (United States)

    Adar, Tomer; Ben-Ami, Ronen; Elstein, Deborah; Zimran, Ari; Berliner, Shlomo; Yedgar, Saul; Barshtein, Gershon

    2006-08-01

    Gaucher disease is associated with increased red blood cell (RBC) aggregation, but the pathophysiological significance of this phenomenon and its correlation with disease manifestations are unclear. RBC aggregation was evaluated in 43 patients with Gaucher disease and 53 healthy controls. Dynamic RBC aggregation was examined in a narrow-gap flow chamber at varying shear stress. Compared with the controls, RBC aggregation in Gaucher disease was increased by 25%. Comparison of RBC aggregation in autologous plasma and in dextran (500 kDa) showed an increase both in plasma-dependent (extrinsic) and -independent (intrinsic) RBC aggregation. Subgroup analysis revealed that increased RBC aggregation was limited to patients with an intact spleen. RBC aggregation in patients did not correlate with plasma fibrinogen concentration, disease severity, enzyme replacement therapy or genotype. We conclude that RBC aggregation is increased in patients with Gaucher disease and an intact spleen, possibly reflecting the accumulation of glucocerebroside and other substances in the plasma and RBC membranes of these patients. Our results do not support a role for RBC aggregation in the pathogenesis of vascular complications of Gaucher disease.

  9. Protein aggregate myopathies

    Directory of Open Access Journals (Sweden)

    Sharma M

    2005-01-01

    Full Text Available Protein aggregate myopathies (PAM are an emerging group of muscle diseases characterized by structural abnormalities. Protein aggregate myopathies are marked by the aggregation of intrinsic proteins within muscle fibers and fall into four major groups or conditions: (1 desmin-related myopathies (DRM that include desminopathies, a-B crystallinopathies, selenoproteinopathies caused by mutations in the, a-B crystallin and selenoprotein N1 genes, (2 hereditary inclusion body myopathies, several of which have been linked to different chromosomal gene loci, but with as yet unidentified protein product, (3 actinopathies marked by mutations in the sarcomeric ACTA1 gene, and (4 myosinopathy marked by a mutation in the MYH-7 gene. While PAM forms 1 and 2 are probably based on impaired extralysosomal protein degradation, resulting in the accumulation of numerous and diverse proteins (in familial types in addition to respective mutant proteins, PAM forms 3 and 4 may represent anabolic or developmental defects because of preservation of sarcomeres outside of the actin and myosin aggregates and dearth or absence of other proteins in these actin or myosin aggregates, respectively. The pathogenetic principles governing protein aggregation within muscle fibers and subsequent structural sarcomeres are still largely unknown in both the putative catabolic and anabolic forms of PAM. Presence of inclusions and their protein composition in other congenital myopathies such as reducing bodies, cylindrical spirals, tubular aggregates and others await clarification. The hitherto described PAMs were first identified by immunohistochemistry of proteins and subsequently by molecular analysis of their genes.

  10. Charged Dust Aggregate Interactions

    Science.gov (United States)

    Matthews, Lorin; Hyde, Truell

    2015-11-01

    A proper understanding of the behavior of dust particle aggregates immersed in a complex plasma first requires a knowledge of the basic properties of the system. Among the most important of these are the net electrostatic charge and higher multipole moments on the dust aggregate as well as the manner in which the aggregate interacts with the local electrostatic fields. The formation of elongated, fractal-like aggregates levitating in the sheath electric field of a weakly ionized RF generated plasma discharge has recently been observed experimentally. The resulting data has shown that as aggregates approach one another, they can both accelerate and rotate. At equilibrium, aggregates are observed to levitate with regular spacing, rotating about their long axis aligned parallel to the sheath electric field. Since gas drag tends to slow any such rotation, energy must be constantly fed into the system in order to sustain it. A numerical model designed to analyze this motion provides both the electrostatic charge and higher multipole moments of the aggregate while including the forces due to thermophoresis, neutral gas drag, and the ion wakefield. This model will be used to investigate the ambient conditions leading to the observed interactions. This research is funded by NSF Grant 1414523.

  11. Assessing the Relevance of Anomie Theory for Explaining Spatial Variation in Lethal Criminal Violence: An Aggregate-Level Analysis of Homicide within the United States

    Directory of Open Access Journals (Sweden)

    Eric P. Baumer

    2008-11-01

    Full Text Available One of the most influential statements in the anomie theory tradition has been Merton’s argument that the volume of instrumental property crime should be higher where there is a greater imbalance between the degree of commitment to monetary success goals and the degree of commitment to legitimate means of pursuing such goals. Contemporary anomie theories stimulated by Merton’s perspective, most notably Messner and Rosenfeld’s institutional anomie theory, have expanded the scope conditions by emphasizing lethal criminal violence as an outcome to which anomie theory is highly relevant, and virtually all contemporary empirical studies have focused on applying the perspective to explaining spatial variation in homicide rates. In the present paper, we argue that current explications of Merton’s theory and IAT have not adequately conveyed the relevance of the core features of the anomie perspective to lethal violence. We propose an expanded anomie model in which an unbalanced pecuniary value system – the core causal variable in Merton’s theory and IAT – translates into higher levels of homicide primarily in indirect ways by increasing levels of firearm prevalence, drug market activity, and property crime, and by enhancing the degree to which these factors stimulate lethal outcomes. Using aggregate-level data collected during the mid-to-late 1970s for a sample of relatively large social aggregates within the U.S., we find a significant effect on homicide rates of an interaction term reflecting high levels of commitment to monetary success goals and low levels of commitment to legitimate means. Virtually all of this effect is accounted for by higher levels of property crime and drug market activity that occur in areas with an unbalanced pecuniary value system. Our analysis also reveals that property crime is more apt to lead to homicide under conditions of high levels of structural disadvantage. These and other findings underscore the

  12. Impact of Particle Aggregation on Nanoparticle Reactivity

    Science.gov (United States)

    Jassby, David

    2011-12-01

    decline in hydroxyl radical generation could be attributed to two key parameters. First, increased aggregate size was associated with increased particle shadowing, as determined from the observed decrease in the rate of optically induced transitions. Secondly, aggregate structure was associated both with increased shadowing (denser aggregates exhibited more shadowing than similarly sized loose aggregates), and with an increase in radical quenching on neighboring particle surfaces in an aggregate. Aggregation had a positive impact on hydroxylated fullerene membrane separation, increasing removal efficiency to around 80%, regardless of transmembrane pressure. However, the type of electrolyte used determined whether aggregation was successful at increasing removal. Divalent ions, capable of forming strong covalent bonds with surface oxygen groups, increased removal efficiency and made it pressure insensitive. In contrast, monovalent ions increased removal efficiency slightly, but maintained the pressure dependence of the removal efficiency. Evidence is presented to support the hypothesis that divalently aggregated hydroxylated fullerenes deform under increased pressure and partially penetrate the membrane. Finally, nanoparticle reactive properties depend on the primary particle aggregation state. Both size and structure are key factors when evaluating nanomaterial reactivity under aggregation-inducing conditions. However, the impact of aggregation is not easily predicted. Some materials exhibit a decreased reactivity while others experience an increase. Therefore, the impact of aggregation on nanoparticle reactive properties must be evaluated on a material-by-material basis, while considering all of the particle and aggregate characteristics as well as environmental ones.

  13. Aggregated Computational Toxicology Online Resource

    Data.gov (United States)

    U.S. Environmental Protection Agency — Aggregated Computational Toxicology Online Resource (AcTOR) is EPA's online aggregator of all the public sources of chemical toxicity data. ACToR aggregates data...

  14. Aeronautical Information System Replacement -

    Data.gov (United States)

    Department of Transportation — Aeronautical Information System Replacement is a web-enabled, automation means for the collection and distribution of Service B messages, weather information, flight...

  15. Blasted copper slag as fine aggregate in Portland cement concrete.

    Science.gov (United States)

    Dos Anjos, M A G; Sales, A T C; Andrade, N

    2017-07-01

    The present work focuses on assessing the viability of applying blasted copper slag, produced during abrasive blasting, as fine aggregate for Portland cement concrete manufacturing, resulting in an alternative and safe disposal method. Leaching assays showed no toxicity for this material. Concrete mixtures were produced, with high aggregate replacement ratios, varying from 0% to 100%. Axial compressive strength, diametrical compressive strength, elastic modulus, physical indexes and durability were evaluated. Assays showed a significant improvement in workability, with the increase in substitution of fine aggregate. With 80% of replacement, the concrete presented lower levels of water absorption capacity. Axial compressive strength and diametrical compressive strength decreased, with the increase of residue replacement content. The greatest reductions of compressive strength were found when the replacement was over 40%. For tensile strength by diametrical compression, the greatest reduction occurred for the concrete with 80% of replacement. After the accelerated aging, results of mechanic properties showed a small reduction of the concrete with blasted copper slag performance, when compared with the reference mixture. Results indicated that the blasted copper slag is a technically viable material for application as fine aggregate for concrete mixtures. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Protein Colloidal Aggregation Project

    Science.gov (United States)

    Oliva-Buisson, Yvette J. (Compiler)

    2014-01-01

    To investigate the pathways and kinetics of protein aggregation to allow accurate predictive modeling of the process and evaluation of potential inhibitors to prevalent diseases including cataract formation, chronic traumatic encephalopathy, Alzheimer's Disease, Parkinson's Disease and others.

  17. Propagation of Tau aggregates.

    Science.gov (United States)

    Goedert, Michel; Spillantini, Maria Grazia

    2017-05-30

    Since 2009, evidence has accumulated to suggest that Tau aggregates form first in a small number of brain cells, from where they propagate to other regions, resulting in neurodegeneration and disease. Propagation of Tau aggregates is often called prion-like, which refers to the capacity of an assembled protein to induce the same abnormal conformation in a protein of the same kind, initiating a self-amplifying cascade. In addition, prion-like encompasses the release of protein aggregates from brain cells and their uptake by neighbouring cells. In mice, the intracerebral injection of Tau inclusions induced the ordered assembly of monomeric Tau, followed by its spreading to distant brain regions. Short fibrils constituted the major species of seed-competent Tau. The existence of several human Tauopathies with distinct fibril morphologies has led to the suggestion that different molecular conformers (or strains) of aggregated Tau exist.

  18. Aggregation and Averaging.

    Science.gov (United States)

    Siegel, Irving H.

    The arithmetic processes of aggregation and averaging are basic to quantitative investigations of employment, unemployment, and related concepts. In explaining these concepts, this report stresses need for accuracy and consistency in measurements, and describes tools for analyzing alternative measures. (BH)

  19. Cell aggregation and sedimentation.

    Science.gov (United States)

    Davis, R H

    1995-01-01

    The aggregation of cells into clumps or flocs has been exploited for decades in such applications as biological wastewater treatment, beer brewing, antibiotic fermentation, and enhanced sedimentation to aid in cell recovery or retention. More recent research has included the use of cell aggregation and sedimentation to selectively separate subpopulations of cells. Potential biotechnological applications include overcoming contamination, maintaining plasmid-bearing cells in continuous fermentors, and selectively removing nonviable hybridoma cells from perfusion cultures.

  20. Use of Recycled Aggregate and Fly Ash in Concrete Pavement

    Directory of Open Access Journals (Sweden)

    Myle N. James

    2011-01-01

    Full Text Available Problem statement: Recycled materials aggregate from the demolished concrete structures and fly ash from burning coal shows the possible application as structural and non structural components in concrete structures. This research aims to evaluate the feasibility of using concrete containing recycled concrete aggregate and fly ash in concrete pavement. Approach: Two water cement ratio (0.45 and 0.55 the compressive strength, modulus of electricity and flexural strength for concrete with recycled aggregate and fly ash with 0, 25% replacing cement in mass were considered. Results: The material properties of recycled aggregate concrete with fly ash indicate comparable results with that of concrete with natural aggregate and without fly ash. Conclusion/Recommendations: The recycled materials could be used in concrete pavement and it will promote the sustainability of concrete.

  1. Influence of recycled fine aggregates on the resistance of mortars to magnesium sulfate attack.

    Science.gov (United States)

    Lee, Seung-Tae

    2009-08-01

    The influence of recycled fine aggregates, which had been reclaimed from field-demolished concretes, on the resistance of mortar specimens to magnesium sulfate attack was investigated. Mortar specimens were prepared with recycled fine aggregates at different replacement levels (0%, 25%, 50%, 75% and 100% of natural fine aggregate by mass). The mortar specimens were exposed to 4.24% magnesium sulfate solution for about 1 year at ambient temperature, and regularly monitored for visual appearance, compressive strength loss and expansion. Additionally, in order to identify products of magnesium sulfate attack, mortar samples incorporating 0%, 25% and 100% replacement levels of the recycled fine aggregates were examined by X-ray diffraction (XRD) technique. Experimental results confirmed that the use of recycled fine aggregates up to a maximum 50% replacement level is effective under severe magnesium sulfate environment, irrespective of type of recycled fine aggregates. However, the worse performance was observed in mortar specimens incorporating 100% replacement level. It was found that the water absorption of recycled fine aggregates affected deterioration of mortar specimens, especially at a higher replacement level. XRD results indicated that the main cause of deterioration of the mortar specimens was primarily due to the formation of gypsum and thaumasite by magnesium sulfate attack. In addition, it appeared that the conversion of C-S-H into M-S-H by the attack probably influenced mechanical deterioration of mortar specimens with recycled fine aggregates.

  2. Influence of Phenylalanine on Carotenoid Aggregation

    Science.gov (United States)

    Lu, L.; Ni, X.; Luo, X.

    2015-01-01

    The carotenoids lutein and β-carotene form, in 1:1 ethanol-water mixtures H-aggregates, of different strengths. The effects of phenylalanine on these aggregates were recorded by UV-Vis absorption, steady-state fluorescence, and Raman spectra. The H-aggregate of lutein was characterized by a large 78 nm blue shift in the absorption spectra, confirming the strong coupling between hydroxyl groups of adjacent molecules. The 15 nm blue shift in the β-carotene mixture also indicates that it was assembled by weak coupling between polyenes. After adding phenylalanine, the reducing absorption strength of the aggregates of lutein and reappearance of vibrational substructure indicate that the hydroxyl and amino groups of phenylalanine may coordinate to lutein and disaggregate the H-aggregates. However, phenylalanine had no effect on aggregates of β-carotene. The Raman spectra show three bands of carotenoids whose intensities decreased with increasing phenylalanine concentration. The frequency of ν1 corresponding to the length of the conjugated region was more sensitive to the solution of lutein. This coordination of phenylalanine to lutein could increase the length of the conjugated region. In addition, phenylalanine significantly affected the excited electronic states of carotenoids, which were crucial in the energy transfer from carotenoids to chlorophyll a in vivo.

  3. COIN Project: Towards a zero-waste technology for concrete aggregate production in Norway

    Science.gov (United States)

    Cepuritis, Rolands; Willy Danielsen, Svein

    2014-05-01

    COIN Project: Towards a zero-waste technology for concrete aggregate production in Norway Rolands Cepuritis, Norcem/NTNU and Svein Willy Danielsen, SINTEF Aggregate production is a mining operation where no purification of the "ore" is necessary. Still it is extremely rare that an aggregate production plant is operating on the basis of zero-waste concept. This is since historically the fine crushed aggregate (particles with a size of less than 2, 4 or sometimes 8 mm) has been regarded as a by-product or waste of the more valuable coarse aggregate production. The reason is that the crushed coarse aggregates can easily replace coarse rounded natural stones in almost any concrete composition; while, the situation with the sand is different. The production of coarse aggregate normally yields fine fractions with rough surface texture, flaky or elongated particles an inadequate gradation. When such a material replaces smooth and rounded natural sand grains in a concrete mix, the result is usually poor and much more water and cement has to be used to achieve adequate concrete flow. The consequences are huge stockpiles of the crushed fine fractions that can't be sold (mass balance problems) for the aggregate producers, sustainability problems for the whole industry and environmental issues for society due to dumping and storing of the fine co-generated material. There have been attempts of utilising the material in concrete before; however, they have mostly ended up in failure. There have been attempts to adjust the crushed sand to the properties of the natural sand, which would still give a lot of waste, especially if the grading would have to be adjusted and the high amounts of fines abundantly present in the crushed sand would have to be removed. Another fundamental reason for failure has been that historically such attempts have mainly ended up in a research carried out by people (both industrial and academic) with aggregate background (= parties willing to find market

  4. A Survey of Distributed Data Aggregation Algorithms

    CERN Document Server

    Jesus, Paulo; Almeida, Paulo Sérgio

    2011-01-01

    Distributed data aggregation is an important task, allowing the decentralized determination of meaningful global properties, that can then be used to direct the execution of other applications. The resulting values result from the distributed computation of functions like COUNT, SUM and AVERAGE. Some application examples can found to determine the network size, total storage capacity, average load, majorities and many others. In the last decade, many different approaches have been proposed, with different trade-offs in terms of accuracy, reliability, message and time complexity. Due to the considerable amount and variety of aggregation algorithms, it can be difficult and time consuming to determine which techniques will be more appropriate to use in specific settings, justifying the existence of a survey to aid in this task. This work reviews the state of the art on distributed data aggregation algorithms, providing three main contributions. First, it formally defines the concept of aggregation, characterizin...

  5. Radiation Source Replacement Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Griffin, Jeffrey W.; Moran, Traci L.; Bond, Leonard J.

    2010-12-01

    This report summarizes a Radiation Source Replacement Workshop in Houston Texas on October 27-28, 2010, which provided a forum for industry and researchers to exchange information and to discuss the issues relating to replacement of AmBe, and potentially other isotope sources used in well logging.

  6. Dynamics of proteins aggregation. I. Universal scaling in unbounded media

    Science.gov (United States)

    Zheng, Size; Javidpour, Leili; Shing, Katherine S.; Sahimi, Muhammad

    2016-10-01

    It is well understood that in some cases proteins do not fold correctly and, depending on their environment, even properly-folded proteins change their conformation spontaneously, taking on a misfolded state that leads to protein aggregation and formation of large aggregates. An important factor that contributes to the aggregation is the interactions between the misfolded proteins. Depending on the aggregation environment, the aggregates may take on various shapes forming larger structures, such as protein plaques that are often toxic. Their deposition in tissues is a major contributing factor to many neuro-degenerative diseases, such as Alzheimer's, Parkinson's, amyotrophic lateral sclerosis, and prion. This paper represents the first part in a series devoted to molecular simulation of protein aggregation. We use the PRIME, a meso-scale model of proteins, together with extensive discontinuous molecular dynamics simulation to study the aggregation process in an unbounded fluid system, as the first step toward MD simulation of the same phenomenon in crowded cellular environments. Various properties of the aggregates have been computed, including dynamic evolution of aggregate-size distribution, mean aggregate size, number of peptides that contribute to the formation of β sheets, number of various types of hydrogen bonds formed in the system, radius of gyration of the aggregates, and the aggregates' diffusivity. We show that many of such quantities follow dynamic scaling, similar to those for aggregation of colloidal clusters. In particular, at long times the mean aggregate size S(t) grows with time as, S(t) ˜ tz, where z is the dynamic exponent. To our knowledge, this is the first time that the qualitative similarity between aggregation of proteins and colloidal aggregates has been pointed out.

  7. Metaconcrete: Engineered aggregates for enhanced dynamic performance

    Science.gov (United States)

    Mitchell, Stephanie J.

    This work presents the development and investigation of a new type of concrete for the attenuation of waves induced by dynamic excitation. Recent progress in the field of metamaterials science has led to a range of novel composites which display unusual properties when interacting with electromagnetic, acoustic, and elastic waves. A new structural metamaterial with enhanced properties for dynamic loading applications is presented, which is named metaconcrete. In this new composite material the standard stone and gravel aggregates of regular concrete are replaced with spherical engineered inclusions. Each metaconcrete aggregate has a layered structure, consisting of a heavy core and a thin compliant outer coating. This structure allows for resonance at or near the eigenfrequencies of the inclusions, and the aggregates can be tuned so that resonant oscillations will be activated by particular frequencies of an applied dynamic loading. The activation of resonance within the aggregates causes the overall system to exhibit negative effective mass, which leads to attenuation of the applied wave motion. To investigate the behavior of metaconcrete slabs under a variety of different loading conditions a finite element slab model containing a periodic array of aggregates is utilized. The frequency dependent nature of metaconcrete is investigated by considering the transmission of wave energy through a slab, which indicates the presence of large attenuation bands near the resonant frequencies of the aggregates. Applying a blast wave loading to both an elastic slab and a slab model that incorporates the fracture characteristics of the mortar matrix reveals that a significant portion of the supplied energy can be absorbed by aggregates which are activated by the chosen blast wave profile. The transfer of energy from the mortar matrix to the metaconcrete aggregates leads to a significant reduction in the maximum longitudinal stress, greatly improving the ability of the material

  8. Muscle MR imaging in tubular aggregate myopathy.

    Directory of Open Access Journals (Sweden)

    Valeria Beltrame

    Full Text Available PURPOSE: To evaluate with Magnetic Resonance (MR the degree of fatty replacement and edematous involvement in skeletal muscles in patients with Tubular Aggregate Myopathy (TAM. To asses the inter-observer agreement in evaluating muscle involvement and the symmetry index of fatty replacement. MATERIALS AND METHODS: 13 patients were evaluated by MR to ascertain the degree of fatty replacement (T1W sequences according to Mercuri's scale, and edema score (STIR sequences according to extent and site. RESULTS: Fatty replacement mainly affects the posterior superficial compartment of the leg; the anterior compartment is generally spared. Edema was generally poor and almost only in the superficial compartment of the leg. The inter-observer agreement is very good with a Krippendorff's coefficient >0.9. Data show a total symmetry in the muscular replacement (McNemar-Bowker test with p = 1. CONCLUSIONS: MR reveals characteristic muscular involvement, and is a reproducible technique for evaluation of TAM. There may also be a characteristic involvement of the long and short heads of the biceps femoris. It is useful for aimed biopsies, diagnostic hypotheses and evaluation of disease progression.

  9. Optical dynamics of molecular aggregates

    NARCIS (Netherlands)

    de Boer, Steven

    2006-01-01

    The subject of this thesis is the spectroscopy and dynamics of molecular aggregates in amorphous matrices. Aggregates of three different molecules were studied. The molecules are depicted in Fig. (1.1). Supersaturated solutions of these molecules show aggregate formation. Aggregation is a process si

  10. Subcutaneous Immunoglobulin-G Replacement Therapy with Preparations Currently Available in the United States for Intravenous or Intramuscular Use: Reasons and Regimens

    Directory of Open Access Journals (Sweden)

    Chouksey Akhilesh

    2005-09-01

    Full Text Available Abstract For patients who require replacement therapy for primary immunodeficiency, subcutaneous infusions of immunoglobulin G (IgG may be preferable to intravenous infusions for several reasons. However, at present, there is no preparation marketed for use by this route in North America. In this article, we describe the reasons patients have selected this route of therapy and the range of treatment regimens used. Approximately 20% of our patients have chosen the subcutaneous route, mainly because of adverse effects from intravenous (IV infusions or difficulties with venous access. Unit dose regimens using whole bottles of currently available 16% intramuscular preparations or sucrose-containing lyophilized preparations intended for IV use but reconstituted to 15% IgG for subcutaneous administration were individually tailored to each patient. In most cases, self-infusions or home infusions were administered once or twice a week, most commonly requiring two subcutaneous sites and 2 to 3 hours per infusion. On average, patients took 0.18 mL of IgG per kilogram of body weight per site per hour. There were no systemic adverse effects. In patients for whom comparative data were available, trough serum IgG levels were higher with subcutaneous therapy than with IV therapy.

  11. Feasibility Studies of Palm Oil Mill Waste Aggregates for the Construction Industry

    Directory of Open Access Journals (Sweden)

    Jegathish Kanadasan

    2015-09-01

    Full Text Available The agricultural industry in Malaysia has grown rapidly over the years. Palm oil clinker (POC is a byproduct obtained from the palm oil industry. Its lightweight properties allows for its utilization as an aggregate, while in powder form as a filler material in concrete. POC specimens obtained throughout each state in Malaysia were investigated to evaluate the physical, chemical, and microstructure characteristics. Variations between each state were determined and their possible contributory factors were assessed. POC were incorporated as a replacement material for aggregates and their engineering characteristics were ascertained. Almost 7% of density was reduced with the introduction of POC as aggregates. A sustainability assessment was made through greenhouse gas emission (GHG and cost factor analyses to determine the contribution of the addition of POC to the construction industry. Addition of POC helps to lower the GHG emission by 9.6% compared to control specimens. By channeling this waste into the construction industry, an efficient waste-management system can be promoted; thus, creating a cleaner environment. This study is also expected to offer some guides and directions for upcoming research works on the incorporation of POC.

  12. 75 FR 25217 - Intent To Prepare an Environmental Impact Statement for Northwest Aggregates' Previously...

    Science.gov (United States)

    2010-05-07

    ... Department of the Army; Corps of Engineers Intent To Prepare an Environmental Impact Statement for Northwest... (Corps) Seattle District is preparing an Environmental Impact Statement (EIS) to analyze the... Aggregates dock replacement project and potential environmental issues including completed construction...

  13. Metaconcrete: designed aggregates to enhance dynamic performance

    Science.gov (United States)

    Mitchell, Stephanie J.; Pandolfi, Anna; Ortiz, Michael

    2014-04-01

    We propose a new type of concrete for the attenuation of elastic waves induced by dynamic excitation. In this metamaterial, which we call metaconcrete, the stone, sand, and gravel aggregates of standard concrete are replaced with spherical inclusions consisting of a heavy metal core coated with a soft outer layer. These engineered aggregates can be tuned so that particular frequencies of a propagating blast wave will activate resonant oscillations of the heavy mass within the inclusions. The resonant behavior causes the system to exhibit negative effective mass, and this interaction between the wave motion and the resonant aggregates results in the attenuation of the applied dynamic loading. We introduce the concept of negative mass by deriving the effective momentum mass for the system and we define the geometrical and material parameters for the design of resonant aggregates. We develop finite element models for the analysis of metaconcrete behavior, defining a section of slab containing a periodic arrangement of inclusions. By computing the energy histories for the system when subject to a blast load, we show that there is a transfer of energy between the inclusions and the surrounding mortar. The inclusions are able to absorb a significant portion of the applied energy, resulting in a reduction in the amount of stress carried by the mortar phase and greatly improving the ability of the material to resist damage under explosive dynamic loading.

  14. Simulation of red blood cell aggregation in shear flow.

    Science.gov (United States)

    Lim, B; Bascom, P A; Cobbold, R S

    1997-01-01

    A simulation model has been developed for red blood cell (RBC) aggregation in shear flow. It is based on a description of the collision rates of RBC, the probability of particles sticking together, and the breakage of aggregates by shear forces. The influence of shear rate, hematocrit, aggregate fractal dimension, and binding strength on aggregation kinetics were investigated and compared to other theoretical and experimental results. The model was used to simulate blood flow in a long large diameter tube under steady flow conditions at low Reynolds numbers. The time and spatial distribution of the state of aggregation are shown to be in qualitative agreement with previous B-mode ultrasound studies in which a central region of low echogenicity was noted. It is suggested that the model can provide a basis for interpreting prior measurements of ultrasound echogenicity and may help relate them to the local state of aggregation.

  15. Fractals of Silica Aggregates

    Institute of Scientific and Technical Information of China (English)

    ZhinhongLi; DongWu; Yuhansun; JunWang; YiLiu; BaozhongDong; Zhinhong

    2001-01-01

    Silica aggregates were prepared by base-catalyzed hydrolysis and condensation of alkoxides in alcohol.Polyethylene glycol(PEG) was used as organic modifier.The sols were characterized using Small Angle X-ray Scattering (SAXS) with synchrotron radiation as X-ray source.The structure evolution during the sol-gel process was determined and described in terms of the fractal geometry.As-produced silica aggregates were found to be mass fractals.The fractl dimensions spanned the regime 2.1-2.6 corresponding to more branched and compact structures.Both RLCA and Eden models dominated the kinetic growth under base-catalyzed condition.

  16. Replacing a Missing Tooth

    Science.gov (United States)

    ... vessels in the tooth pulps are rather large. Drilling down these teeth for crowns may expose the ... porcelain replacement tooth is held in place by metal extensions cemented to the backs of the adjacent ...

  17. Hormone Replacement Therapy

    Science.gov (United States)

    ... before and during menopause, the levels of female hormones can go up and down. This can cause ... hot flashes and vaginal dryness. Some women take hormone replacement therapy (HRT), also called menopausal hormone therapy, ...

  18. Knee joint replacement

    Science.gov (United States)

    ... of your kneecap. Your kneecap is called the patella. The replacement part is usually made from a ... long. Then your surgeon will: Move your kneecap (patella) out of the way, then cut the ends ...

  19. Knee joint replacement - slideshow

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/presentations/100088.htm Knee joint replacement - series—Normal anatomy To use the ... to slide 4 out of 4 Overview The knee is a complex joint. It contains the distal ...

  20. The Willapa Bay Oyster Reserves in Washington State: Fishery collapse, creating a sustainable replacement, and the potential for habitat conservation and restoration

    Science.gov (United States)

    Oysters have been an important resource in Washington state since the mid 1800’s and are intimately associated with recent history of the Willapa Bay estuary just as they have defined social culture around much larger US east coast systems. The Willapa Bay oyster reserves were set aside to preserve...

  1. Using a symbolic process model as input for model-based fMRI analysis : Locating the neural correlates of problem state replacements

    NARCIS (Netherlands)

    Borst, J.P.; Taatgen, N.A.; Van Rijn, D.H.

    2011-01-01

    In this paper, a model-based analysis method for fMRI is used with a high-level symbolic process model. Participants performed a triple-task in which intermediate task information needs to be updated frequently. Previous work has shown that the associated resource - the problem state resource - acts

  2. Multi-Dimensional Aggregation for Temporal Data

    DEFF Research Database (Denmark)

    Böhlen, M. H.; Gamper, J.; Jensen, Christian Søndergaard

    2006-01-01

    when the data hold. In temporal databases, intervals typically capture the states of reality that the data apply to, or capture when the data are, or were, part of the current database state. This paper proposes a new aggregation operator that addresses several challenges posed by interval data. First......Business Intelligence solutions, encompassing technologies such as multi-dimensional data modeling and aggregate query processing, are being applied increasingly to non-traditional data. This paper extends multi-dimensional aggregation to apply to data with associated interval values that capture......, the intervals to be associated with the result tuples may not be known in advance, but depend on the actual data. Such unknown intervals are accommodated by allowing result groups that are specified only partially. Second, the operator contends with the case where an interval associated with data expresses...

  3. Product Platform Replacements

    DEFF Research Database (Denmark)

    Sköld, Martin; Karlsson, Christer

    2012-01-01

    Purpose – It is argued in this article that too little is known about product platforms and how to deal with them from a manager's point of view. Specifically, little information exists regarding when old established platforms are replaced by new generations in R&D and production environments...... originality and value is achieved by focusing on product platform replacements believed to represent a growing management challenge....

  4. Properties of Industrial Slag as Fine Aggregate in Concrete

    Directory of Open Access Journals (Sweden)

    A. Ananthi

    2015-04-01

    Full Text Available The main objective of this paper is to use the industrial waste such as bottom ash and Weld Slag (WS as the partial replacement for fine aggregates in concrete. This paper presents the chemical analysis and strength properties of industrial solid waste such as bottom ash, weld slag 1 (WS 1 and weld slag 2 (WS 2. Their chemical compositions were identified by X-ray powder diffraction (XRD analysis. The qualitative and quantitative elemental analysis of the bottom ash and weld slag was recognized by energy dispersive X-ray analysis and their morphology were studied by Scanning Electron Microscope (SEM. The compressive strength of concrete with 10% replacement of fine aggregate to the industrial waste shows higher strength than the normal concrete and hence this industrial waste can be used as fine aggregate in concrete.

  5. Durability Indicators in High Absorption Recycled Aggregate Concrete

    Directory of Open Access Journals (Sweden)

    Luis F. Jiménez

    2015-01-01

    Full Text Available The use of recycled aggregates in structural concrete production has the inconvenience of increasing the fluid transport properties, such as porosity, sorptivity, and permeability, which reduces the resistance against penetration of environmental loads such as carbon dioxide and chloride ion. In this paper, behavior of ten concrete mixtures with different percentages of coarse aggregate replacement was studied. The recycled material was recovered by crushing of concrete rubble and had high absorption values. The results showed that it is possible to achieve good resistance to carbonation and chloride penetration with up to 50% replacement of recycled coarse aggregate for 0.5 water/cement ratio. Finally, new indexes for porosity and sorptivity were proposed to assess the quality of concrete.

  6. Monitoring the Aggregation of Dansyl Chloride in Acetone through Fluorescence Measurements

    Institute of Scientific and Technical Information of China (English)

    FANG,Yu(房喻); YIN,Yi-Qing(尹艺青); HU,Dao-Dao(胡道道); GAO,Gai-Ling(高改玲)

    2002-01-01

    The aggregation of dansyl chloride (DNS-Cl) in acetone has been studied in detail by steady-state fluorescence techniques. It has been demonstrated that DNS-Cl is stable in acetone during purification and aggregation study processes. The aggregates are not solvolyzed in acetone, and do not take part in any chemical reactions either. It has been found that DNS-Cl tends to aggregate even when its concentration is much lower than its solubility in acetone. The aggregation is reversible, and both the aggregation and the deaggregation are very slow processes.Introduction of SDS has a positive effect upon the formation and stabilization of the aggregates.

  7. Geoinformation Generalization by Aggregation

    Directory of Open Access Journals (Sweden)

    Tomislav Jogun

    2016-12-01

    Full Text Available Geoinformation generalization can be divided into model generalization and cartographic generalization. Model generalization is the supervised reduction of data in a model, while cartographic generalization is the reduction of the complexity of map content adapted to the map scale, and/or use by various generalization operators (procedures. The topic of this paper is the aggregation of geoinformation. Generally, aggregation is the joining of nearby, congenial objects, when the distance between them is smaller than the minimum sizes. Most researchers in geoinformation generalization have focused on line features. However, the appearance of web-maps with point features and choropleth maps has led to the development of concepts and algorithms for the generalization of point and polygonal features. This paper considers some previous theoretical premises and actual examples of aggregation for point, line and polygonal features. The algorithms for aggregation implemented in commercial and free GIS software were tested. In the conclusion, unresolved challenges that occur in dynamic cartographic visualizations and cases of unusual geometrical features are highlighted.

  8. Erosion of dust aggregates

    CERN Document Server

    Seizinger, Alexander; Kley, Wilhelm

    2013-01-01

    Aims: The aim of this work is to gain a deeper insight into how much different aggregate types are affected by erosion. Especially, it is important to study the influence of the velocity of the impacting projectiles. We also want to provide models for dust growth in protoplanetary disks with simple recipes to account for erosion effects. Methods: To study the erosion of dust aggregates we employed a molecular dynamics approach that features a detailed micro-physical model of the interaction of spherical grains. For the first time, the model has been extended by introducing a new visco-elastic damping force which requires a proper calibration. Afterwards, different sample generation methods were used to cover a wide range of aggregate types. Results: The visco-elastic damping force introduced in this work turns out to be crucial to reproduce results obtained from laboratory experiments. After proper calibration, we find that erosion occurs for impact velocities of 5 m/s and above. Though fractal aggregates as ...

  9. Diffusion in aggregated soil.

    NARCIS (Netherlands)

    Rappoldt, C.

    1992-01-01

    The structure of an aggregated soil is characterized by the distribution of the distance from an arbitrary point in the soil to the nearest macropore or crack. From this distribution an equivalent model system is derived to which a diffusion model can be more easily applied. The model system consist

  10. Face-specific Replacement of Calcite by Amorphous Silica Nanoparticles

    Science.gov (United States)

    Liesegang, M.; Milke, R.; Neusser, G.; Mizaikoff, B.

    2016-12-01

    Amorphous silica, composed of nanoscale spheres, is an important biomineral, alteration product of silicate rocks on the Earth's surface, and precursor material for stable silicate minerals. Despite constant progress in silica sphere synthesis, fundamental knowledge of natural silica particle interaction and ordering processes leading to colloidal crystals is absent so far. To understand the formation pathways of silica spheres in a geologic environment, we investigated silicified Cretaceous mollusk shell pseudomorphs from Coober Pedy (South Australia) using focused ion beam (FIB)-SEM tomography, petrographic microscopy, µ-XRD, and EMPA. The shells consist of replaced calcite crystals (product, the advancement of synchronized dissolution and precipitation fronts along lattice planes is essential. We assume that the volume-preserving replacement process proceeds via a face-specific dissolution-precipitation mechanism with intermediate subparticle aggregation and subsequent layer-by-layer deposition of spheres along a planar surface. Porosity created during the replacement reaction allows permanent fluid access to the propagating reaction interface. Fluid pH and ionic strength remain constant throughout the replacement process, permitting continuous silica nanoparticle formation and diffusion-limited colloid aggregation. Our study provides a natural example of the transformation of an atomic crystal to an amorphous, mesoscale ordered material; thus, links the research fields of natural colloidal crystal formation, carbonate-silica replacement, and crystallization by oriented particle aggregation (CPA).

  11. H- and J-aggregation of fluorene-based chromophores.

    Science.gov (United States)

    Deng, Yonghong; Yuan, Wen; Jia, Zhe; Liu, Gao

    2014-12-11

    Understanding of H- and J-aggregation behaviors in fluorene-based polymers is significant both for determining the origin of various red-shifted emissions occurring in blue-emitting polyfluorenes and for developing polyfluorene-based device performance. In this contribution, we demonstrate a new theory of the H- and J-aggregation of polyfluorenes and oligofluorenes, and understand the influence of chromosphere aggregation on their photoluminescent properties. H- and J-aggregates are induced by a continuous increasing concentration of the oligofluorene or polyfluorene solution. A relaxed molecular configuration is simulated to illustrate the spatial arrangement of the bonding of fluorenes. It is indicated that the relaxed state adopts a 21 helical backbone conformation with a torsion angle of 18° between two connected repeat units. This configuration makes the formation of H- and J-aggregates through the strong π-π interaction between the backbone rings. A critical aggregation concentration is observed to form H- and J-aggregates for both polyfluorenes and oligofluorenes. These aggregates show large spectral shifts and distinct shape changes in photoluminescent excitation (PLE) and emission (PL) spectroscopy. Compared with "isolated" chromophores, H-aggregates induce absorption spectral blue-shift and fluorescence spectral red-shift but largely reduce fluorescence efficiency. "Isolated" chromophores not only refer to "isolated molecules" but also include those associated molecules if their conjugated backbones are not compact enough to exhibit perturbed absorption and emission. J-aggregates induce absorption spectral red-shift and fluorescence spectral red-shift but largely enhance fluorescence efficiency. The PLE and PL spectra also show that J-aggregates dominate in concentrated solutions. Different from the excimers, the H- and J-aggregate formation changes the ground-state absorption of fluorene-based chromophores. H- and J-aggregates show changeable

  12. The Impact Analysis of Social Marketing Mix on the Intention of Replacing Single-Occupant Vehicles with Urban Public Transport Case Study: Staff Working at State Universities of Isfahan

    Directory of Open Access Journals (Sweden)

    Hossein Rezaie Dolatabadi

    2013-04-01

    Full Text Available Nowadays, the growing use of private cars in cities has led to air pollution; hence, breathing clean air as a basic human right has become drastically difficult. Isfahan as the second industrial city of Iran has struggled for years with this problem. In order to reduce the intensity of air pollution, there are many suggestions amongst which replacing Single-Occupant Vehicles (SOVs with Urban Public Transport (UPT can be noted. In this study, by using the principles of social marketing and Theory of Planned Behavior (TPB a conceptual model has been presented to evaluate the impact analysis of social marketing mix on the intention of staff working at the State Universities of Isfahan City in order to replace SOVs with UPT. Data were collected using a closed questionnaire and the model was evaluated by using Amos Graphic Software. The results show that social marketing mix has a significant positive effect on behavioral beliefs and normative beliefs, but a negative effect on the control beliefs of the staff. The effects of behavioral beliefs on attitude, normative beliefs on subjective norms, and control beliefs on perceived behavioral control are significant positive. Also the effects of three variables: attitude, subjective norm, and perceived behavioral control on the intention of the staff are significant positive. Finally, a significant positive effect of social marketing mix on the intention of staff was approved.

  13. Using of Local Limestone as Aggregate in Concrete Mixture

    Directory of Open Access Journals (Sweden)

    Dr.Muyasser M. Jomaa'h

    2012-03-01

    Full Text Available This research deals with the field investigations and construction properties for using limestone as a lightweight course aggregate in concrete mixture in stead of normal coarse aggregate. Concrete cubes samples have been prepared with dimensions of 150*150*150 mm according to ASTM. For these samples the normal coarse aggregate was replaced by 100% coarse crushed limestone. Three types of limestone which were used (Al-Sinea, Makhool and Himreen, it was found that the Al-Sinea type of limestone gave a good combination (fcu =32.11MPa without admixtures. The obtained results showed a suitable reduction in dead loads of structural elements and cost. Accordingly, the usage of limestone will improve the structural applications and concrete mix properties to attain economic viability. These above results make limestone as a good alternative of normal coarse aggregate

  14. 200 North Aggregate Area source AAMS report

    Energy Technology Data Exchange (ETDEWEB)

    1993-06-01

    This report presents the results of an aggregate area management study (AAMS) for the 200 North Aggregate Area in the 200 Areas of the US Department of Energy (DOE) Hanford Site in Washington State. This scoping level study provides the basis for initiating Remedial Investigation/Feasibility Study (RI/FS) activities under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) or Resource Conservation and Recovery Act (RCRA) Facility Investigations (RFI) and Corrective Measures Studies (CMS) under RCRA. This report also integrates select RCRA treatment, storage, or disposal (TSD) closure activities with CERCLA and RCRA past practice investigations.

  15. Compressive and Tensile Capacity of Recycled Aggregate Concrete (RAC with Glass as Supplement Material

    Directory of Open Access Journals (Sweden)

    Suraya Hani Adnan

    2013-12-01

    Full Text Available The amount of construction waste is increased significantly over the years due to reconstruction and the demolition of old buildings. One of the major challenges of our present society is to protect the environment by recycling the existing construction waste. This study concerned on two types of variable in the production of concrete which are the utilization of coarse recycled aggregate and utilization of different supplement ratio of fine glass wastes to cement. To evaluate the viability of this study, an experimental work was performed in order to monitor the mechanical behavior of such concrete. The compression and splitting tensile strength of concrete were determined on this study. From the result, it is conclude that the utilization of recycled aggregate does not much affect in the uniaxial compressive strength and splitting tensile strength of concrete, for replacement ratio up to 25 %. However, the utilization of fine glass as supplement material to cement is increase the uniaxial compressive and splitting tensile strength of concrete, for supplement ratio up to 5 %. Thus, it can be stated that the optimum concrete mixture is the mixture of 25 % recycled aggregate and 5% glass.

  16. Aggregate distribution and associated organic carbon influenced by cover crops

    Science.gov (United States)

    Barquero, Irene; García-González, Irene; Benito, Marta; Gabriel, Jose Luis; Quemada, Miguel; Hontoria, Chiquinquirá

    2013-04-01

    Replacing fallow with cover crops during the non-cropping period seems to be a good alternative to diminish soil degradation by enhancing soil aggregation and increasing organic carbon. The aim of this study was to analyze the effect of replacing fallow by different winter cover crops (CC) on the aggregate distribution and C associated of an Haplic Calcisol. The study area was located in Central Spain, under semi-arid Mediterranean climate. A 4-year field trial was conducted using Barley (Hordeum vulgare L.) and Vetch (Vicia sativa L.) as CC during the intercropping period of maize (Zea mays L.) under irrigation. All treatments were equally irrigated and fertilized. Maize was directly sown over CC residues previously killed in early spring. Composite samples were collected at 0-5 and 5-20 cm depths in each treatment on autumn of 2010. Soil samples were separated by wet sieving into four aggregate-size classes: large macroaggregates ( >2000 µm); small macroaggregates (250-2000 µm); microaggregates (53-250 µm); and Organic carbon associated to each aggregate-size class was measured by Walkley-Black Method. Our preliminary results showed that the aggregate-size distribution was dominated by microaggregates (48-53%) and the cover crops increased aggregate size resulting in a higher MWD (0.28 mm) in comparison with fallow (0.20 mm) in the 0-5 cm layer. Barley showed a higher MWD than fallow also in 5-20 cm layer. Organic carbon concentrations in aggregate-size classes at top layer followed the order: large macroaggregates > small macroaggregates > microaggregates > silt + clay size. Treatments did not influence C concentration in aggregate-size classes. In conclusion, cover crops improved soil structure increasing the proportion of macroaggregates and MWD being Barley more effective than Vetch at subsurface layer.

  17. Effect of Glass Powder on Chloride Ion Transport and Alkali-aggregate Reaction Expansion of Lightweight Aggregate Concrete

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi; SHI Caijun; SONG Jianming

    2009-01-01

    The effects of glass powder on the strength development, chloride permeability and potential alkali-aggregate reaction expansion of lightweight aggregate concrete were investigated.Ground blast furnace slag, coal fly ash and silica fume were used as reference materials. The re-placement of cement with 25% glass powder slightly decreases the strengthes at 7 and 28 d, but shows no effect on 90 d's. Silica fume is very effective in improving both the strength and chloride penetra-tion resistance, while ground glass powder is much more effective than blast furnace slag and fly ash in improving chloride penetration resistance of the concrete. When expanded shale or clay is used as coarse aggregate, the concrete containing glass powder does not exhibit deleterious expansion even if alkali-reactive sand is used as fine aggregate of the concrete.

  18. Ceramic ware waste as coarse aggregate for structural concrete production.

    Science.gov (United States)

    García-González, Julia; Rodríguez-Robles, Desirée; Juan-Valdés, Andrés; Morán-Del Pozo, Julia M; Guerra-Romero, M Ignacio

    2015-01-01

    The manufacture of any kind of product inevitably entails the production of waste. The quantity of waste generated by the ceramic industry, a very important sector in Spain, is between 5% and 8% of the final output and it is therefore necessary to find an effective waste recovery method. The aim of the study reported in the present article was to seek a sustainable means of managing waste from the ceramic industry through the incorporation of this type of waste in the total replacement of conventional aggregate (gravel) used in structural concrete. Having verified that the recycled ceramic aggregates met all the technical requirements imposed by current Spanish legislation, established in the Code on Structural Concrete (EHE-08), then it is prepared a control concrete mix and the recycled concrete mix using 100% recycled ceramic aggregate instead of coarse natural aggregate. The concretes obtained were subjected to the appropriate tests in order to conduct a comparison of their mechanical properties. The results show that the concretes made using ceramic sanitary ware aggregate possessed the same mechanical properties as those made with conventional aggregate. It is therefore possible to conclude that the reuse of recycled ceramic aggregate to produce recycled concrete is a feasible alternative for the sustainable management of this waste.

  19. Flexural fatigue characteristics of steel fiber reinforced recycled aggregate concrete (SFRRAC

    Directory of Open Access Journals (Sweden)

    Heeralal M.

    2009-01-01

    Full Text Available This research work is aimed at investigating the flexural fatigue behavior of Steel Fiber Reinforced Recycled Aggregate Concrete (SFRRAC. This study gains importance in view of the wide potential for demolished concrete to serve as a source of quality aggregate feed stock in a variety of structural and non-structural applications. This is a continuation of a series of investigations being conducted aimed at optimizing the utilization of recycled aggregate concrete in rigid pavements. A total of 72 standard flexure specimens of 100mm x 100mm x 450mm were cast and tested for flexure under both static and fatigue loading. The parameters of the investigation included the different replacements of recycled aggregate in natural aggregate, presence of steel fiber and different stress levels. The study showed that the recycled aggregates can be used in rigid pavements also and the inclusion of fibers can benefit the fatigue performance of recycled aggregate concrete.

  20. Synchronized Data Aggregation for Wireless Sensor Network

    DEFF Research Database (Denmark)

    Dnyaneshwar, Mantri; Prasad, Neeli R.; Prasad, Ramjee

    2014-01-01

    Wireless Sensor Networks (WSNs) are used for monitoring and data collection purposes. A key challenge in effective data collection is to schedule and synchronize the activities of the nodes with global clock. This paper proposes the Synchronized Data Aggregation Algorithm (SDA) using spanning tree...... mechanism. It provides network-wide time synchronization for sensor network. In the initial stage algorithm established the hierarchical structure in the network and then perform the pair - wise synchronization. SDA aggregate data with a global time scale throughout the network. The aggregated packets...... are scheduled using TDMA as the MAC layer protocol. Simulation results show that, SDA gives promising result of energy efficiency and delay as compared with state-of-the-art solutions....

  1. Principles of Need and the Aggregation Thesis.

    Science.gov (United States)

    Gustavsson, Erik; Juth, Niklas

    2017-09-02

    Principles of need are constantly referred to in health care priority setting. The common denominator for any principle of need is that it will ascribe some kind of special normative weight to people being worse off. However, this common ground does not answer the question how a plausible principle of need should relate to the aggregation of benefits across individuals. Principles of need are sometimes stated as being incompatible with aggregation and sometimes characterized as accepting aggregation in much the same way as utilitarians do. In this paper we argue that if one wants to take principles of need seriously both of these positions have unreasonable implications. We then characterize and defend a principle of need consisting of sufficientarian elements as well as prioritarian which avoids these unreasonable implications.

  2. Chaperone effects on prion and nonprion aggregates.

    Science.gov (United States)

    Rikhvanov, Eugene G; Romanova, Nina V; Chernoff, Yury O

    2007-01-01

    Exposure to high temperature or other stresses induces a synthesis of heat shock proteins. Many of these proteins are molecular chaperones, and some of them help cells to cope with heat-induced denaturation and aggregation of other proteins. In the last decade, chaperones have received increased attention in connection with their role in maintenance and propagation of the Saccharomyces cerevisiae prions, infectious or heritable agents transmitted at the protein level. Recent data suggest that functioning of the chaperones in reactivation of heat-damaged proteins and in propagation of prions is based on the same molecular mechanisms but may lead to different consequences depending on the type of aggregate. In both cases the concerted and balanced action of "chaperones' team," including Hsp104, Hsp70, Hsp40 and possibly other proteins, determines whether a misfolded protein is to be incorporated into an aggregate, rescued to the native state or targeted for degradation.

  3. Women Up, Men Down: The Clinical Impact of Replacing the Framingham Risk Score with the Reynolds Risk Score in the United States Population

    Science.gov (United States)

    Tattersall, Matthew C.; Gangnon, Ronald E.; Karmali, Kunal N.; Keevil, Jon G.

    2012-01-01

    Background The Reynolds Risk Score (RRS) is one alternative to the Framingham Risk Score (FRS) for cardiovascular risk assessment. The Adult Treatment Panel III (ATP III) integrated the FRS a decade ago, but with the anticipated release of ATP IV, it remains uncertain how and which risk models will be integrated into the recommendations. We sought to define the effects in the United States population of a transition from the FRS to the RRS for cardiovascular risk assessment. Methods Using the National Health and Nutrition Examination Surveys, we assessed FRS and RRS in 2,502 subjects representing approximately 53.6 Million (M) men (ages 50–79) and women (ages 45–79), without cardiovascular disease or diabetes. We calculated the proportion reclassified by RRS and the subset whose LDL-C goal achievement changed. Results Compared to FRS, the RRS assigns a higher risk category to 13.9% of women and 9.1% of men while assigning a lower risk to 35.7% of men and 2% of women. Overall, 4.7% of women and 1.1% of men fail to meet newly intensified LDL-C goals using the RRS. Conversely, 10.5% of men and 0.6% of women now meet LDL-C goal using RRS when they had not by FRS. Conclusion In the U.S. population the RRS assigns a new risk category for one in six women and four of nine men. In general, women increase while men decrease risk. In conclusion, adopting the RRS for the 53.6 million eligible U.S. adults would result in intensification of clinical management in 1.6 M additional women and 2.10 M fewer men. PMID:22984495

  4. Women up, men down: the clinical impact of replacing the Framingham Risk Score with the Reynolds Risk Score in the United States population.

    Directory of Open Access Journals (Sweden)

    Matthew C Tattersall

    Full Text Available BACKGROUND: The Reynolds Risk Score (RRS is one alternative to the Framingham Risk Score (FRS for cardiovascular risk assessment. The Adult Treatment Panel III (ATP III integrated the FRS a decade ago, but with the anticipated release of ATP IV, it remains uncertain how and which risk models will be integrated into the recommendations. We sought to define the effects in the United States population of a transition from the FRS to the RRS for cardiovascular risk assessment. METHODS: Using the National Health and Nutrition Examination Surveys, we assessed FRS and RRS in 2,502 subjects representing approximately 53.6 Million (M men (ages 50-79 and women (ages 45-79, without cardiovascular disease or diabetes. We calculated the proportion reclassified by RRS and the subset whose LDL-C goal achievement changed. RESULTS: Compared to FRS, the RRS assigns a higher risk category to 13.9% of women and 9.1% of men while assigning a lower risk to 35.7% of men and 2% of women. Overall, 4.7% of women and 1.1% of men fail to meet newly intensified LDL-C goals using the RRS. Conversely, 10.5% of men and 0.6% of women now meet LDL-C goal using RRS when they had not by FRS. CONCLUSION: In the U.S. population the RRS assigns a new risk category for one in six women and four of nine men. In general, women increase while men decrease risk. In conclusion, adopting the RRS for the 53.6 million eligible U.S. adults would result in intensification of clinical management in 1.6 M additional women and 2.10 M fewer men.

  5. Robotic mitral valve replacement.

    Science.gov (United States)

    Senay, Sahin; Gullu, Ahmet Umit; Kocyigit, Muharrem; Degirmencioglu, Aleks; Karabulut, Hasan; Alhan, Cem

    2014-01-01

    Robotic surgical techniques allow surgeons to perform mitral valve surgery. This procedure has gained acceptance, particularly for mitral valve repair in degenerative mitral disease. However, mitral repair may not always be possible, especially in severely calcified mitral valve of rheumatic origin. This study demonstrates the basic concepts and technique of robotic mitral valve replacement for valve pathologies that are not suitable for repair.

  6. Soil aggregation under different management systems

    Directory of Open Access Journals (Sweden)

    Cibele Mascioli Rebello Portella

    2012-12-01

    Full Text Available Considering that the soil aggregation reflects the interaction of chemical, physical and biological soil factors, the aim of this study was evaluate alterations in aggregation, in an Oxisol under no-tillage (NT and conventional tillage (CT, since over 20 years, using as reference a native forest soil in natural state. After analysis of the soil profile (cultural profile in areas under forest management, samples were collected from the layers 0-5, 5-10, 10-20 and 20-40 cm, with six repetitions. These samples were analyzed for the aggregate stability index (ASI, mean weighted diameter (MWD, mean geometric diameter (MGD in the classes > 8, 8-4, 4-2, 2-1, 1-0.5, 0.5-0.25, and < 0.25 mm, and for physical properties (soil texture, water dispersible clay (WDC, flocculation index (FI and bulk density (Bd and chemical properties (total organic carbon - COT, total nitrogen - N, exchangeable calcium - Ca2+, and pH. The results indicated that more intense soil preparation (M < NT < PC resulted in a decrease in soil stability, confirmed by all stability indicators analyzed: MWD, MGD, ASI, aggregate class distribution, WDC and FI, indicating the validity of these indicators in aggregation analyses of the studied soil.

  7. Development of Ecoefficient Engineered Cementitious Composites Using Supplementary Cementitious Materials as a Binder and Bottom Ash Aggregate as Fine Aggregate

    Directory of Open Access Journals (Sweden)

    Jin Wook Bang

    2015-01-01

    Full Text Available The purpose of this study is to develop ecoefficient engineered cementitious composites (ECC using supplementary cementitious materials (SCMs, including fly ash (FA and blast furnace slag (SL as a binder material. The cement content of the ECC mixtures was replaced by FA and SL with a replacement rate of 25%. In addition, the fine aggregate of the ECC was replaced by bottom ash aggregate (BA with a substitution rate of 10%, 20%, and 30%. The influences of ecofriendly aggregates on fresh concrete properties and on mechanical properties were experimentally investigated. The test results revealed that the substitution of SCMs has an advantageous effect on fresh concrete’s properties; however, the increased water absorption and the irregular shape of the BA can potentially affect the fresh concrete’s properties. The substitution of FA and SL in ECC led to an increase in frictional bond at the interface between PVA fibers and matrix, improved the fiber dispersion, and showed a tensile strain capacity ranging from 3.3% to 3.5%. It is suggested that the combination of SCMs (12.5% FA and 12.5% SL and the BA aggregate with the substitution rate of 10% can be effectively used in ECC preparation.

  8. EFFECT OF USING STEEL SLAG AGGREGATE ON MECHANICAL PROPERTIES OF CONCRETE

    Directory of Open Access Journals (Sweden)

    Sultan A. Tarawneh

    2014-01-01

    Full Text Available This study presents an evaluation of the physical and mechanical properties and characteristics of steel slag aggregate concrete in comparison with the typical crushed limestone stone aggregate concrete. Hardened concrete consist of more than 70% aggregate due to the high demand in building construction and the increase of the amount of disposed waste material, suppliers and researchers are exploring the use of alternative materials which could preserve natural sources and save the environment. In this study, steel slag was used as an aggregate replacement in conventional concrete mixes. Steel slag which is mainly consists of calcium carbonate is produced as a by-product during the oxidation process in steel industry. Steel slag was selected due to its characteristics, which are almost similar to conventional aggregates and the fact that it is easily obtainable as a by-product of the steel industry. As a result, utilization of steel slag will save natural resources and clean environment. Furthermore, results have shown that slag aggregate has better abrasion factor and impact value than conventional aggregate. Thorough investigation of the results have indicated that the amount of increase in compressive strength at age of 7 days are much more than that of age 28 days for all types of aggregate replacement. This indicates that the added slag could work as accelerator at early age while at 28 days age, the effect is reduced. The fine slag replacement scores the highest effect.

  9. 再生细骨料湿度状态及掺量对混凝土工作性及抗压强度的影响%Influence of the moisture states and content of recycled fine aggregate on the workability and compressive strength of concrete

    Institute of Scientific and Technical Information of China (English)

    陈远远; 季韬; 江其东; 梁咏宁

    2013-01-01

    The total water-cement ratio of recycled fine aggregate concrete was kept the same.The moisture states (namely air-dried (AD),oven-dried (OD) and saturated surface-dried (SSD)states) and content of recycled fine aggregate were varied.The initial slump and the slump loss,the 3,7 and 28 d compressive strengths of recycled fine aggregate concrete were measured.The test results show that,for the same total water-cement ratio,when the recycled fine aggregate content is the same,the initial slump and the slump loss of concrete decrease and the 3,7 and 28 d compressive strengths of recycled fine aggregate concrete increase with the increase of the moisture of recycled fine aggregate from oven-dried,air-dried to saturated surface-dried states.For the same moisture state,the initial slump increases,the slump loss decreases and the 3,7 and 28 d compressive strengths of recycled fine aggregate concrete decrease with the increase of recycled fine aggregate content.%保持再生细骨料混凝土的总水灰比一致,变化再生细骨料的湿度状态(气干、烘干和饱和面干)及掺量,测出新拌再生细骨料混凝土初始坍落度和坍落度损失,以及3、7和28 d再生细骨料混凝土的抗压强度.研究结果表明:在总水灰比不变的情况下,当再生细骨料掺量一定时,随着其湿度状态从烘干到气干再到饱和面干的变化,混凝土的初始坍落度与坍落度损失减小,混凝土3、7和28 d抗压强度增大;当再生细骨料保持任一湿度状态时,随着其在混凝土中掺量的增大,混凝土的初始坍落度增大,坍落度损失减小,混凝土3、7和28 d抗压强度减小.

  10. Hydrophobic aggregation of ultrafine kaolinite

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao-ping; HU Yue-hua; LIU Run-Qing

    2008-01-01

    The hydrophobic aggregation of ultrafine kaolinite in cationic surfactant suspension was investigated by sedimentation test, zeta potential measurement and SEM observation. SEM images reveal that kaolinite particles show the self-aggregation of edge-face in acidic media, the aggregation of edge-face and edge-edge in neutral media, and the dispersion in alkaline media due to electrostatic repulsion. In the presence of the dodecylammonium acetate cationic surfactant and in neutral and alkaline suspension, the hydrophobic aggregation of face-face is demonstrated. The zeta potential of kaolinite increases with increasing the concentration of cationic surfactant. The small and loose aggregation at a low concentration but big and tight aggregation at a high concentration is presented At pH=7 alkyl quarterly amine salt CTAB has the best hydrophobic aggregation among three cationic surfactants, namely, dodecylammonium acetate, alkyl quarterly amine salts 1227 and CTAB.

  11. Absorption Spectra of Astaxanthin Aggregates

    CERN Document Server

    Olsina, Jan; Minofar, Babak; Polivka, Tomas; Mancal, Tomas

    2012-01-01

    Carotenoids in hydrated polar solvents form aggregates characterized by dramatic changes in their absorption spectra with respect to monomers. Here we analyze absorption spectra of aggregates of the carotenoid astaxanthin in hydrated dimethylsulfoxide. Depending on water content, two types of aggregates were produced: H-aggregates with absorption maximum around 390 nm, and J-aggregates with red-shifted absorption band peaking at wavelengths >550 nm. The large shifts with respect to absorption maximum of monomeric astaxanthin (470-495 nm depending on solvent) are caused by excitonic interaction between aggregated molecules. We applied molecular dynamics simulations to elucidate structure of astaxanthin dimer in water, and the resulting structure was used as a basis for calculations of absorption spectra. Absorption spectra of astaxanthin aggregates in hydrated dimethylsulfoxide were calculated using molecular exciton model with the resonance interaction energy between astaxanthin monomers constrained by semi-e...

  12. Non-Arrhenius protein aggregation.

    Science.gov (United States)

    Wang, Wei; Roberts, Christopher J

    2013-07-01

    Protein aggregation presents one of the key challenges in the development of protein biotherapeutics. It affects not only product quality but also potentially impacts safety, as protein aggregates have been shown to be linked with cytotoxicity and patient immunogenicity. Therefore, investigations of protein aggregation remain a major focus in pharmaceutical companies and academic institutions. Due to the complexity of the aggregation process and temperature-dependent conformational stability, temperature-induced protein aggregation is often non-Arrhenius over even relatively small temperature windows relevant for product development, and this makes low-temperature extrapolation difficult based simply on accelerated stability studies at high temperatures. This review discusses the non-Arrhenius nature of the temperature dependence of protein aggregation, explores possible causes, and considers inherent hurdles for accurately extrapolating aggregation rates from conventional industrial approaches for selecting accelerated conditions and from conventional or more advanced methods of analyzing the resulting rate data.

  13. Nonlinear and stochastic modelling of energy transfer in Scheibe aggregates

    DEFF Research Database (Denmark)

    Christiansen, Peter Leth; Rasmussen, Kim; Gaididei, Yu. B.

    1996-01-01

    The oxacyanine Scheibe aggregate is modelled by a two-dimensional cubicnonlinear Schrödinger equation with multiplicative noise, accounting forthermal fluctuations. For a possible choise of the physical parameterscollapse of the initial state...

  14. Study of Biomass Calcite as Fine Aggregate of Concrete

    Institute of Scientific and Technical Information of China (English)

    WANG Jian; YU Yan

    2012-01-01

    The possibility of using crushed oyster shell to partly replace the fine aggregate of concrete was evaluated. The compressive strength and slump of concrete mixture with different amount of crushed oyster shell were tested and thus the appropriate dosage was determined. Additionally, the compatibility with super plasticizer and the stability in NazSO4 solution were also discussed to prove the feasibility of oyster shell as fine aggregate of concrete. The microstructure of concrete was observed with XRD and SEM techniques. This research provides the basis for the application of waste biomass calcite.

  15. Thermal unfolding and aggregation of actin.

    Science.gov (United States)

    Levitsky, Dmitrii I; Pivovarova, Anastasiya V; Mikhailova, Valeria V; Nikolaeva, Olga P

    2008-09-01

    Actin is one of the most abundant proteins in nature. It is found in all eukaryotes and plays a fundamental role in many diverse and dynamic cellular processes. Also, actin is one of the most ubiquitous proteins because actin-like proteins have recently been identified in bacteria. Actin filament (F-actin) is a highly dynamic structure that can exist in different conformational states, and transitions between these states may be important in cytoskeletal dynamics and cell motility. These transitions can be modulated by various factors causing the stabilization or destabilization of actin filaments. In this review, we look at actin stabilization and destabilization as expressed by changes in the thermal stability of actin; specifically, we summarize and analyze the existing data on the thermal unfolding of actin as measured by differential scanning calorimetry. We also analyze in vitro data on the heat-induced aggregation of actin, the process that normally accompanies actin thermal denaturation. In this respect, we focus on the effects of small heat shock proteins, which can prevent the aggregation of thermally denatured actin with no effect on actin thermal unfolding. As a result, we have proposed a mechanism describing the thermal denaturation and aggregation of F-actin. This mechanism explains some of the special features of the thermal unfolding of actin filaments, including the effects of their stabilization and destabilization; it can also explain how small heat shock proteins protect the actin cytoskeleton from damage caused by the accumulation of large insoluble aggregates under heat shock conditions.

  16. Ulnar head replacement.

    Science.gov (United States)

    Herbert, Timothy J; van Schoonhoven, Joerg

    2007-03-01

    Recent years have seen an increasing awareness of the anatomical and biomechanical significance of the distal radioulnar joint (DRUJ). With this has come a more critical approach to surgical management of DRUJ disorders and a realization that all forms of "excision arthroplasty" can only restore forearm rotation at the expense of forearm stability. This, in turn, has led to renewed interest in prosthetic replacement of the ulnar head, a procedure that had previously fallen into disrepute because of material failures with early implants, in particular, the Swanson silicone ulnar head replacement. In response to these early failures, a new prosthesis was developed in the early 1990s, using materials designed to withstand the loads across the DRUJ associated with normal functional use of the upper limb. Released onto the market in 1995 (Herbert ulnar head prosthesis), clinical experience during the last 10 years has shown that this prosthesis is able to restore forearm function after ulnar head excision and that the materials (ceramic head and noncemented titanium stem), even with normal use of the limb, are showing no signs of failure in the medium to long term. As experience with the use of an ulnar head prosthesis grows, so does its acceptance as a viable and attractive alternative to more traditional operations, such as the Darrach and Sauve-Kapandji procedures. This article discusses the current indications and contraindications for ulnar head replacement and details the surgical procedure, rehabilitation, and likely outcomes.

  17. Research on Judgment Aggregation Based on Logic

    Directory of Open Access Journals (Sweden)

    Li Dai

    2014-05-01

    Full Text Available Preference aggregation and judgment aggregation are two basic research models of group decision making. And preference aggregation has been deeply studied in social choice theory. However, researches of social choice theory gradually focus on judgment aggregation which appears recently. Judgment aggregation focuses on how to aggregate many consistent logical formulas into one, from the perspective of logic. We try to start with judgment aggregation model based on logic and then explore different solutions to problem of judgment aggregation.

  18. Waste tyre rubberized concrete: properties at fresh and hardened state.

    Science.gov (United States)

    Aiello, M A; Leuzzi, F

    2010-01-01

    The main objective of this paper is to investigate the properties of various concrete mixtures at fresh and hardened state, obtained by a partial substitution of coarse and fine aggregate with different volume percentages of waste tyres rubber particles, having the same dimensions of the replaced aggregate. Workability, unit weight, compressive and flexural strength and post-cracking behaviour were evaluated and a comparison of the results for the different rubcrete mixtures were proposed in order to define the better mix proportions in terms of mechanical properties of the rubberized concrete. Results showed in this paper were also compared to data reported in literature. Moreover, a preliminary geometrical, physical and mechanical characterization on scrap tyre rubber shreds was made. The rubberized concrete mixtures showed lower unit weight compared to plain concrete and good workability. The results of compressive and flexural tests indicated a larger reduction of mechanical properties of rubcrete when replacing coarse aggregate rather than fine aggregate. On the other hand, the post-cracking behaviour of rubberized concrete was positively affected by the substitution of coarse aggregate with rubber shreds, showing a good energy absorption and ductility indexes in the range observed for fibrous concrete, as suggested by standard (ASTM C1018-97, 1997).

  19. Development of construction materials using nano-silica and aggregates recycled from construction and demolition waste.

    Science.gov (United States)

    Mukharjee, Bibhuti Bhusan; Barai, Sudhirkumar V

    2015-06-01

    The present work addresses the development of novel construction materials utilising commercial grade nano-silica and recycled aggregates retrieved from construction and demolition waste. For this, experimental work has been carried out to examine the influence of nano-silica and recycled aggregates on compressive strength, modulus of elasticity, water absorption, density and volume of voids of concrete. Fully natural and recycled aggregate concrete mixes are designed by replacing cement with three levels (0.75%, 1.5% and 3%) of nano-silica. The results of the present investigation depict that improvement in early days compressive strength is achieved with the incorporation of nano-silica in addition to the restoration of reduction in compressive strength of recycled aggregate concrete mixes caused owing to the replacement of natural aggregates by recycled aggregates. Moreover, the increase in water absorption and volume of voids with a reduction of bulk density was detected with the incorporation of recycled aggregates in place of natural aggregates. However, enhancement in density and reduction in water absorption and volume of voids of recycled aggregate concrete resulted from the addition of nano-silica. In addition, the results of the study reveal that nano-silica has no significant effect on elastic modulus of concrete.

  20. Study of the behavior of aggregate of calcined clay for use in permeable pavements for the city of Manaus; Estudo do comportamento de agregado sintetico de argila calcinada para uso em pavimentos permeaveis para a cidade de Manaus

    Energy Technology Data Exchange (ETDEWEB)

    Oliveira, M.S.; Vilela, P.A.T.; Araujo, V.S., E-mail: oliveirasmichelle@gmail.com [Universidade do Estado do Amazonas (UEAM), AM (Brazil)

    2016-07-01

    Research on the production of ceramic aggregates and their use in paving in the country began in the 80’s in the search for an alternative material that could replace the pebble or crushed stone, studied the clay, considered an abundant mineral resource by virtue of being the predominant soil in this region and which were made synthetic calcinated clay aggregates (ASAC), for their application in permeable paving concrete motivated by the lack of permeable areas. The study consists of the characterization of materials for manufacture of concrete slabs permeable and the assessment of the effects of synthetic aggregate on its properties in fresh and hardened state. The ceramic bodies were subjected to tests of X-ray diffraction, determination of chemical composition and plasticity. The results indicate that the use of synthetic clusters is a viable alternative for the production of porous concrete. (author)

  1. RILEM recommendations for the prevention of damage by alkali-aggregate reactions in new concrete structures state-of-the-art report of the RILEM technical committee 219-ACS

    CERN Document Server

    Sims, Ian

    2016-01-01

    This book contains the full set of RILEM Recommendations which have been produced to enable engineers, specifiers and testing houses to design and produce concrete which will not suffer damage arising from alkali reactions in the concrete. There are five recommended test methods for aggregates (designated AAR-1 to AAR-5), and an overall recommendation which describes how these should be used to enable a comprehensive aggregate assessment (AAR-0). Additionally, there are two Recommended International Specifications for concrete (AAR-7.1 & 7.2) and a Preliminary International Specification for dams and other hydro structures (AAR-7.3), which describe how the aggregate assessment can be combined with other measures in the design of the concrete to produce a concrete with a minimised risk of developing damage from alkali-aggregate reactions.

  2. Aggregate and Mineral Resources, PhosphateDeposits1988-This data set represents phosphate deposit areas in Utah., Published in 2001, Smaller than 1:100000 scale, State of Utah Automated Geographic Reference Center.

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — This Aggregate and Mineral Resources dataset, published at Smaller than 1:100000 scale, was produced all or in part from Hardcopy Maps information as of 2001. It is...

  3. Aortic valve replacement

    DEFF Research Database (Denmark)

    Kapetanakis, Emmanouil I; Athanasiou, Thanos; Mestres, Carlos A

    2008-01-01

    BACKGROUND AND AIMS OF THE STUDY: Prompted by anecdotal evidence and observations by surgeons, an investigation was undertaken into the potential differences in implanted aortic valve prosthesis sizes, during aortic valve replacement (AVR) procedures, between northern and southern European...... countries. METHODS: A multi-institutional, non-randomized, retrospective analysis was conducted among 2,932 patients who underwent AVR surgery at seven tertiary cardiac surgery centers throughout Europe. Demographic and perioperative variables including valve size and type, body surface area (BSA) and early...

  4. Total ankle joint replacement.

    Science.gov (United States)

    2016-02-01

    Ankle arthritis results in a stiff and painful ankle and can be a major cause of disability. For people with end-stage ankle arthritis, arthrodesis (ankle fusion) is effective at reducing pain in the shorter term, but results in a fixed joint, and over time the loss of mobility places stress on other joints in the foot that may lead to arthritis, pain and dysfunction. Another option is to perform a total ankle joint replacement, with the aim of giving the patient a mobile and pain-free ankle. In this article we review the efficacy of this procedure, including how it compares to ankle arthrodesis, and consider the indications and complications.

  5. Novel aspects of platelet aggregation

    Directory of Open Access Journals (Sweden)

    Roka-Moya Y. M.

    2014-01-01

    Full Text Available The platelet aggregation is an important process, which is critical for the hemostatic plug formation and thrombosis. Recent studies have shown that the platelet aggregation is more complex and dynamic than it was previously thought. There are several mechanisms that can initiate the platelet aggregation and each of them operates under specific conditions in vivo. At the same time, the influence of certain plasma proteins on this process should be considered. This review intends to summarize the recent data concerning the adhesive molecules and their receptors, which provide the platelet aggregation under different conditions.

  6. Fractal Aggregation Under Rotation

    Institute of Scientific and Technical Information of China (English)

    WU Feng-Min; WU Li-Li; LU Hang-Jun; LI Qiao-Wen; YE Gao-Xiang

    2004-01-01

    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω the fractal dimension decreases with increasing ω, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  7. Fractal Aggregation Under Rotation

    Institute of Scientific and Technical Information of China (English)

    WUFeng-Min; WULi-Li; LUHang-Jun; LIQiao-Wen; YEGao-Xiang

    2004-01-01

    By means of the Monte Carlo simulation, a fractal growth model is introduced to describe diffusion-limited aggregation (DLA) under rotation. Patterns which are different from the classical DLA model are observed and the fractal dimension of such clusters is calculated. It is found that the pattern of the clusters and their fractal dimension depend strongly on the rotation velocity of the diffusing particle. Our results indicate the transition from fractal to non-fractal behavior of growing cluster with increasing rotation velocity, i.e. for small enough angular velocity ω; thefractal dimension decreases with increasing ω;, but then, with increasing rotation velocity, the fractal dimension increases and the cluster becomes compact and tends to non-fractal.

  8. Platelet aggregation following trauma

    DEFF Research Database (Denmark)

    Windeløv, Nis A; Sørensen, Anne M; Perner, Anders

    2014-01-01

    We aimed to elucidate platelet function in trauma patients, as it is pivotal for hemostasis yet remains scarcely investigated in this population. We conducted a prospective observational study of platelet aggregation capacity in 213 adult trauma patients on admission to an emergency department (ED......). Inclusion criteria were trauma team activation and arterial cannula insertion on arrival. Blood samples were analyzed by multiple electrode aggregometry initiated by thrombin receptor agonist peptide 6 (TRAP) or collagen using a Multiplate device. Blood was sampled median 65 min after injury; median injury...... severity score (ISS) was 17; 14 (7%) patients received 10 or more units of red blood cells in the ED (massive transfusion); 24 (11%) patients died within 28 days of trauma: 17 due to cerebral injuries, four due to exsanguination, and three from other causes. No significant association was found between...

  9. Moisture damage of aggregate-bitumen bonds

    OpenAIRE

    Zhang, Jizhe

    2016-01-01

    Moisture damage of the asphalt mixture is defined as the loss of strength, stiffness and durability due to the presence of moisture (in a liquid or vapour state) leading to adhesive failure at the aggregate-bitumen interface and/or the cohesive failure within the bitumen or bitumen-filler mastic. The presence of moisture can accelerate the distress of asphalt pavement in several different modes, such as rutting, fatigue cracking, thermal cracking and the formation of potholes. In the field, t...

  10. Optimal randomized scheduling by replacement

    Energy Technology Data Exchange (ETDEWEB)

    Saias, I.

    1996-05-01

    In the replacement scheduling problem, a system is composed of n processors drawn from a pool of p. The processors can become faulty while in operation and faulty processors never recover. A report is issued whenever a fault occurs. This report states only the existence of a fault but does not indicate its location. Based on this report, the scheduler can reconfigure the system and choose another set of n processors. The system operates satisfactorily as long as, upon report of a fault, the scheduler chooses n non-faulty processors. We provide a randomized protocol maximizing the expected number of faults the system can sustain before the occurrence of a crash. The optimality of the protocol is established by considering a closely related dual optimization problem. The game-theoretic technical difficulties that we solve in this paper are very general and encountered whenever proving the optimality of a randomized algorithm in parallel and distributed computation.

  11. Laboratory Investigation of Fatigue Characteristics of Asphalt Mixtures with Steel Slag Aggregates

    Directory of Open Access Journals (Sweden)

    Hassan Ziari

    2015-01-01

    Full Text Available There are many steel-manufacturing factories in Iran. All of their byproducts, steel slag, are dumped randomly in open areas, causing many environmentally hazardous problems. This research is intended to study the effectiveness of using steel slag aggregate (SSA in improving the engineering properties, especially fatigue life of Asphalt Concrete (AC produced with steel slag. The research started by evaluating the physical properties of the steel slag aggregate. Then the 13 types of mixes which contain steel slag in portion of fine aggregates or in portion of coarse aggregates or in all portions of aggregates were tested. The effectiveness of the SSA was judged by the improvement in Marshall stability, indirect tensile strength, resilient modulus, and fatigue life of the AC samples. It was found that replacing the 50% of the limestone coarse or fine aggregate by SSA improved the mechanical properties of the AC mixes.

  12. The Optimum Replacement of Weapon

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiao; ZHANG Jin-chun

    2002-01-01

    The theory of LCC (Life Cycle Cost) is applied in this paper. The relation between the economic life of weapon and the optimum replacement is analyzed. The method to define the optimum replacement time of weapon is discussed.

  13. Aggregation of MBP in chronic demyelination

    Science.gov (United States)

    Frid, Kati; Einstein, Ofira; Friedman-Levi, Yael; Binyamin, Orli; Ben-Hur, Tamir; Gabizon, Ruth

    2015-01-01

    Objectives Misfolding of key disease proteins to an insoluble state is associated with most neurodegenerative conditions, such as prion, Parkinson, and Alzheimer’s diseases. In this work, and by studying animal models of multiple sclerosis, we asked whether this is also the case for myelin basic protein (MBP) in the late and neurodegenerative phases of demyelinating diseases. Methods To this effect, we tested whether MBP, an essential myelin component, present prion-like properties in animal models of MS, as is the case for Cuprizone-induced chronic demyelination or chronic phases of Experimental Autoimmune Encephalomyelitis (EAE). Results We show here that while total levels of MBP were not reduced following extensive demyelination, part of these molecules accumulated thereafter as aggregates inside oligodendrocytes or around neuronal cells. In chronic EAE, MBP precipitated concomitantly with Tau, a marker of diverse neurodegenerative conditions, including MS. Most important, analysis of fractions from Triton X-100 floatation gradients suggest that the lipid composition of brain membranes in chronic EAE differs significantly from that of naïve mice, an effect which may relate to oxidative insults and subsequently prevent the appropriate insertion and compaction of new MBP in the myelin sheath, thereby causing its misfolding and aggregation. Interpretation Prion-like aggregation of MBP following chronic demyelination may result from an aberrant lipid composition accompanying this pathological status. Such aggregation of MBP may contribute to neuronal damage that occurs in the progressive phase of MS. PMID:26273684

  14. Influence of Fly Ash, Bottom Ash, and Light Expanded Clay Aggregate on Concrete

    Directory of Open Access Journals (Sweden)

    S. Sivakumar

    2015-01-01

    Full Text Available Invention of new methods in strengthening concrete is under work for decades. Developing countries like India use the extensive reinforced construction works materials such as fly ash and bottom ash and other ingredients in RCC construction. In the construction industry, major attention has been devoted to the use of fly ash and bottom ash as cement and fine aggregate replacements. In addition, light expanded clay aggregate has been introduced instead of coarse aggregate to make concrete have light weight. This paper presents the results of a real-time work carried out to form light weight concrete made with fly ash, bottom ash, and light expanded clay aggregate as mineral admixtures. Experimental investigation on concrete mix M20 is done by replacement of cement with fly ash, fine aggregate with bottom ash, and coarse aggregate with light expanded clay aggregate at the rates of 5%, 10%, 15%, 20%, 25%, 30%, and 35% in each mix and their compressive strength and split tensile strength of concrete were discussed for 7, 28, and 56 days and flexural strength has been discussed for 7, 28, and 56 days depending on the optimum dosage of replacement in compressive strength and split tensile strength of concrete.

  15. Power Plant Replacement Study

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Gary

    2010-09-30

    This report represents the final report for the Eastern Illinois University power plant replacement study. It contains all related documentation from consideration of possible solutions to the final recommended option. Included are the economic justifications associated with the chosen solution along with application for environmental permitting for the selected project for construction. This final report will summarize the results of execution of an EPC (energy performance contract) investment grade audit (IGA) which lead to an energy services agreement (ESA). The project includes scope of work to design and install energy conservation measures which are guaranteed by the contractor to be self‐funding over its twenty year contract duration. The cost recovery is derived from systems performance improvements leading to energy savings. The prime focus of this EPC effort is to provide a replacement solution for Eastern Illinois University’s aging and failing circa 1925 central steam production plant. Twenty‐three ECMs were considered viable whose net impact will provide sufficient savings to successfully support the overall project objectives.

  16. Total disc replacement.

    Science.gov (United States)

    Vital, J-M; Boissière, L

    2014-02-01

    Total disc replacement (TDR) (partial disc replacement will not be described) has been used in the lumbar spine since the 1980s, and more recently in the cervical spine. Although the biomechanical concepts are the same and both are inserted through an anterior approach, lumbar TDR is conventionally indicated for chronic low back pain, whereas cervical TDR is used for soft discal hernia resulting in cervicobrachial neuralgia. The insertion technique must be rigorous, with precise centering in the disc space, taking account of vascular anatomy, which is more complex in the lumbar region, particularly proximally to L5-S1. All of the numerous studies, including prospective randomized comparative trials, have demonstrated non-inferiority to fusion, or even short-term superiority regarding speed of improvement. The main implant-related complication is bridging heterotopic ossification with resulting loss of range of motion and increased rates of adjacent segment degeneration, although with an incidence lower than after arthrodesis. A sufficiently long follow-up, which has not yet been reached, will be necessary to establish definitively an advantage for TDR, particularly in the cervical spine. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  17. REPLACEMENT OF FRENCH CARDS

    CERN Multimedia

    HR/SOC

    2001-01-01

    The French Ministry of Foreign Affairs has informed the Organization that it is shortly to replace all diplomatic cards, special cards and employment permits ('attestations de fonctions') now held by members of the personnel and their families. Between 2 July and 31 December 2001, these cards are to be replaced by secure, computerized equivalents. The old cards may continue to be used until 31 December 2001. For the purposes of the handover, members of the personnel must go personally to the cards office (33/1-015), in order to fill in a 'fiche individuelle' form, taking the following documents for themselves and members of their families already in possession of a French card : A recent identity photograph in 4.5 cm x 3.5 cm format. The French card in their possession. An A4 photocopy of the same French card, certified by the cards office as being a true copy. Those members of the personnel whose cards (and/or cards belonging to members of their families) are shortly due to expire, or have recently done...

  18. REPLACEMENT OF FRENCH CARDS

    CERN Multimedia

    Human Resources Division; Cards.Service@cern.ch

    2001-01-01

    The French Ministry of Foreign Affairs is currently replacing all diplomatic cards, special cards and employment permits («attestations de fonctions») held by members of the personnel and their families. These cards are replaced by secure, computerized equivalents. The old cards may no longer be used after 31 December 2001. For the purposes of the handover, members of the personnel must go personally to the cards office (33/1-015) between 8h30 and 12h30, in order to fill in a «fiche individuelle» form, taking the following documents for themselves and members of their families already in possession of a French card : A recent identity photograph in 4.5 cm x 3.5 cm format, the French card in their possession, an A4 photocopy of the same French card, certified by the cards office as being a true copy. Those members of the personnel whose cards (and/or cards belonging to members of their families) are shortly due to expire, or have recently done so, are also requested...

  19. REPLACEMENT OF FRENCH CARDS

    CERN Multimedia

    Human Resources Division

    2001-01-01

    The French Ministry of Foreign Affairs has informed the Organization that it is shortly to replace all diplomatic cards, special cards and employment permits ('attestations de fonctions') now held by members of the personnel and their families. Between 2 July and 31 December 2001, these cards are to be replaced by secure, computerized equivalents. The old cards may continue to be used until 31 December 2001. For the purposes of the handover, members of the personnel are asked to go to the cards office (33/1-015), taking the following documents for themselves and members of their families already in possession of a French card : A recent identity photograph in 4.5 cm x 3.5 cm format, The French card in their possession, an A4 photocopy of the same French card, certified by the cards office as being a true copy. Those members of the personnel whose cards (and/or cards belonging to members of their families) are shortly due to expire, or have recently done so, are also requested to take these items to the c...

  20. REPLACEMENT OF FRENCH CARDS

    CERN Multimedia

    Human Resources Division

    2001-01-01

    The French Ministry of Foreign Affairs has informed the Organization that it is shortly to replace all diplomatic cards, special cards and employment permits ('attestations de fonctions') now held by members of the personnel and their families. Between 2 July and 31 December 2001, these cards are to be replaced by secure, computerized equivalents. A 'personnel office' stamped photocopy of the old cards may continue to be used until 31 December 2001. For the purposes of the handover, members of the personnel must go personally to the cards office (33/1-015), between 8:30 and 12:30, in order to fill a 'fiche individuelle' form (in black ink only), which has to be personally signed by themselves and another separately signed by members of their family, taking the following documents for themselves and members of their families already in possession of a French card : A recent identity photograph in 4.5 cm x 3.5 cm format (signed on the back) The French card in their possession an A4 photocopy of the same Fre...

  1. Power Plant Replacement Study

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Gary

    2010-09-30

    This report represents the final report for the Eastern Illinois University power plant replacement study. It contains all related documentation from consideration of possible solutions to the final recommended option. Included are the economic justifications associated with the chosen solution along with application for environmental permitting for the selected project for construction. This final report will summarize the results of execution of an EPC (energy performance contract) investment grade audit (IGA) which lead to an energy services agreement (ESA). The project includes scope of work to design and install energy conservation measures which are guaranteed by the contractor to be self-funding over its twenty year contract duration. The cost recovery is derived from systems performance improvements leading to energy savings. The prime focus of this EPC effort is to provide a replacement solution for Eastern Illinois University's aging and failing circa 1925 central steam production plant. Twenty-three ECMs were considered viable whose net impact will provide sufficient savings to successfully support the overall project objectives.

  2. Faster Replacement Paths

    CERN Document Server

    Williams, Virginia Vassilevska

    2010-01-01

    The replacement paths problem for directed graphs is to find for given nodes s and t and every edge e on the shortest path between them, the shortest path between s and t which avoids e. For unweighted directed graphs on n vertices, the best known algorithm runtime was \\tilde{O}(n^{2.5}) by Roditty and Zwick. For graphs with integer weights in {-M,...,M}, Weimann and Yuster recently showed that one can use fast matrix multiplication and solve the problem in O(Mn^{2.584}) time, a runtime which would be O(Mn^{2.33}) if the exponent \\omega of matrix multiplication is 2. We improve both of these algorithms. Our new algorithm also relies on fast matrix multiplication and runs in O(M n^{\\omega} polylog(n)) time if \\omega>2 and O(n^{2+\\eps}) for any \\eps>0 if \\omega=2. Our result shows that, at least for small integer weights, the replacement paths problem in directed graphs may be easier than the related all pairs shortest paths problem in directed graphs, as the current best runtime for the latter is \\Omega(n^{2.5...

  3. Power Plant Replacement Study

    Energy Technology Data Exchange (ETDEWEB)

    Reed, Gary

    2010-09-30

    This report represents the final report for the Eastern Illinois University power plant replacement study. It contains all related documentation from consideration of possible solutions to the final recommended option. Included are the economic justifications associated with the chosen solution along with application for environmental permitting for the selected project for construction. This final report will summarize the results of execution of an EPC (energy performance contract) investment grade audit (IGA) which lead to an energy services agreement (ESA). The project includes scope of work to design and install energy conservation measures which are guaranteed by the contractor to be self-funding over its twenty year contract duration. The cost recovery is derived from systems performance improvements leading to energy savings. The prime focus of this EPC effort is to provide a replacement solution for Eastern Illinois University’s aging and failing circa 1925 central steam production plant. Twenty-three ECMs were considered viable whose net impact will provide sufficient savings to successfully support the overall project objectives.

  4. Distribution of chromium contamination and microbial activity in soil aggregates.

    Science.gov (United States)

    Tokunaga, Tetsu K; Wan, Jiamin; Hazen, Terry C; Schwartz, Egbert; Firestone, Mary K; Sutton, Stephen R; Newville, Matthew; Olson, Keith R; Lanzirotti, Antonio; Rao, William

    2003-01-01

    Biogeochemical transformations of redox-sensitive chemicals in soils can be strongly transport-controlled and localized. This was tested through experiments on chromium diffusion and reduction in soil aggregates that were exposed to chromate solutions. Reduction of soluble Cr(VI) to insoluble Cr(II) occurred only within the surface layer of aggregates with higher available organic carbon and higher microbial respiration. Sharply terminated Cr diffusion fronts develop when the reduction rate increases rapidly with depth. The final state of such aggregates consists of a Cr-contaminated exterior, and an uncontaminated core, each having different microbial community compositions and activity. Microbial activity was significantly higher in the more reducing soils, while total microbial biomass was similar in all of the soils. The small fraction of Cr(VI) remaining unreduced resides along external surfaces of aggregates, leaving it potentially available to future transport down the soil profile. Using the Thiele modulus, Cr(VI) reduction in soil aggregates is shown to be diffusion rate- and reaction rate-limited in anaerobic and aerobic aggregates, respectively. Thus, spatially resolved chemical and microbiological measurements are necessary within anaerobic soil aggregates to characterize and predict the fate of Cr contamination. Typical methods of soil sampling and analyses that average over redox gradients within aggregates can erase important biogeochemical spatial relations necessary for understanding these environments.

  5. Contrasting effects of nanoparticle-protein attraction on amyloid aggregation.

    Science.gov (United States)

    Radic, Slaven; Davis, Thomas P; Ke, Pu Chun; Ding, Feng

    2015-01-01

    Nanoparticles (NPs) have been experimentally found to either promote or inhibit amyloid aggregation of proteins, but the molecular mechanisms for such complex behaviors remain unknown. Using coarse-grained molecular dynamics simulations, we investigated the effects of varying the strength of nonspecific NP-protein attraction on amyloid aggregation of a model protein, the amyloid-beta peptide implicated in Alzheimer's disease. Specifically, with increasing NP-peptide attraction, amyloid aggregation on the NP surface was initially promoted due to increased local protein concentration on the surface and destabilization of the folded state. However, further increase of NP-peptide attraction decreased the stability of amyloid fibrils and reduced their lateral diffusion on the NP surface necessary for peptide conformational changes and self-association, thus prohibiting amyloid aggregation. Moreover, we found that the relative concentration between protein and NPs also played an important role in amyloid aggregation. With a high NP/protein ratio, NPs that intrinsically promote protein aggregation may display an inhibitive effect by depleting the proteins in solution while having a low concentration of the proteins on each NP's surface. Our coarse-grained molecular dynamics simulation study offers a molecular mechanism for delineating the contrasting and seemingly conflicting effects of NP-protein attraction on amyloid aggregation and highlights the potential of tailoring anti-aggregation nanomedicine against amyloid diseases.

  6. Temperature dependence of erythrocyte aggregation in vitro by backscattering nephelometry

    Science.gov (United States)

    Sirko, Igor V.; Firsov, Nikolai N.; Ryaboshapka, Olga M.; Priezzhev, Alexander V.

    1997-05-01

    We apply backscattering nephelometry technique to register the alterations of the scattering signal from a whole blood sample due to appearance or disappearance of different types of erythrocyte aggregates in stasis and under controlled shear stress. The measured parameters are: the characteristic times of linear and 3D aggregates formation, and the strength of aggregates of different types. These parameters depend on the sample temperature in the range of 2 divided by 50 degrees C. Temporal parameters of the aggregation process strongly increase at temperature 45 degrees C. For samples of normal blood the aggregates strength parameters do not significantly depend on the sample temperature, whereas for blood samples from patients suffering Sjogren syndrome we observe high increase of the strength of 3D and linear aggregates and decrease of time of linear aggregates formation at low temperature of the sample. This combination of parameters is opposite to that observed in the samples of pathological blood at room temperature. Possible reasons of this behavior of aggregation state of blood and explanation of the observed effects will be discussed.

  7. Exciton dynamics in molecular aggregates

    NARCIS (Netherlands)

    Augulis, R.; Pugžlys, A.; Loosdrecht, P.H.M. van; Pugzlys, A

    2006-01-01

    The fundamental aspects of exciton dynamics in double-wall cylindrical aggregates of cyanine dyes are studied by means of frequency resolved femtosecond pump-probe spectroscopy. The collective excitations of the aggregates, resulting from intermolecular dipole-dipole interactions have the characteri

  8. Aggregate resources in the Netherlands

    NARCIS (Netherlands)

    Meulen, M.J. van der; Gessel, S.F. van; Veldkamp, J.G.

    2005-01-01

    We have built a 3D lithological model of the Netherlands, for the purpose of mapping on-land aggregate resources down to 50 m below the surface. The model consists of voxel cells (1000 · 1000 · 1 m), with lithological composition and aggregate content estimates as primary attributes. These attribute

  9. Exciton dynamics in molecular aggregates

    NARCIS (Netherlands)

    Augulis, R.; Pugžlys, A.; Loosdrecht, P.H.M. van; Pugzlys, A

    2006-01-01

    The fundamental aspects of exciton dynamics in double-wall cylindrical aggregates of cyanine dyes are studied by means of frequency resolved femtosecond pump-probe spectroscopy. The collective excitations of the aggregates, resulting from intermolecular dipole-dipole interactions have the

  10. Toleration, Synthesis or Replacement?

    DEFF Research Database (Denmark)

    Holtermann, Jakob v. H.; Madsen, Mikael Rask

    2016-01-01

    to have considerable problems keeping a clear focus on the key question: What are the implications of this empirical turn in terms of philosophy of legal science, of the social understanding of IL, and, not least, of the place of doctrinal scholarship after the alleged Wende? What is needed, we argue......, in order to answer is not yet another partisan suggestion, but rather an attempt at making intelligible both the oppositions and the possibilities of synthesis between normative and empirical approaches to law. Based on our assessment and rational reconstruction of current arguments and positions, we...... therefore outline a taxonomy consisting of the following three basic, ideal-types in terms of the epistemological understanding of the interface of law and empirical studies: toleration, synthesis and replacement. This tripartite model proves useful with a view to teasing out and better articulating...

  11. Self-aggregation of vapor-liquid phase transition

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The concept of the molecular free path is introduced to derive a criterion distinguishing active molecules from inactive molecules in liquid phase. Based on molecular self-aggregation theory a concept of the critical aggregation concentration (CAC) of active molecules is proposed to describe the physical configuration before the formation of the nuclei in the process of vapor-liquid phase transition. All active molecules exist in the form of the monomer when the concentration of active molecules is lower than CAC, while the active molecules will generate aggregation once the concentration of the active molecules reaches CAC. However, these aggregates with the aggregation number N smaller than 5 can steadily exist in bulk phase. The other excess active molecules can only produce infinite aggregation and form a critical nucleus of vapor-liquid phase transition. Without outer perturbation the state point of CAC corresponds to the critical superheated or supercooled state in the process of vapor-liquid phase transition. With the aggregate property, the interfacial tension between the bulk phase and the tiny new phase is predicted and a correction is made for the classical nucleation rate in a quite good agreement with experimental results.

  12. Molecular aggregation of humic substances

    Science.gov (United States)

    Wershaw, R. L.

    1999-01-01

    Humic substances (HS) form molecular aggregates in solution and on mineral surfaces. Elucidation of the mechanism of formation of these aggregates is important for an understanding of the interactions of HS in soils arid natural waters. The HS are formed mainly by enzymatic depolymerization and oxidation of plant biopolymers. These reactions transform the aromatic and lipid plant components into amphiphilic molecules, that is, molecules that consist of separate hydrophobic (nonpolar) and hydrophilic (polar) parts. The nonpolar parts of the molecules are composed of relatively unaltered segments of plant polymers and the polar parts of carboxylic acid groups. These amphiphiles form membrane-like aggregates on mineral surfaces and micelle-like aggregates in solution. The exterior surfaces of these aggregates are hydrophilic, and the interiors constitute separate hydrophobic liquid-like phases.

  13. Optical monitoring of particle aggregates

    Institute of Scientific and Technical Information of China (English)

    John Gregory

    2009-01-01

    Methods for monitoring particle aggregation are briefly reviewed. Most of these techniques are based on some form of light scattering and may be greatly dependent on the optical properties of aggregates, which are not generally known. As fractal aggregates grow larger their density can become very low and this has important practical consequences for light scattering. For instance, the scattering coefficient may be much less than for solid objects, which means that the aggregates can appear much smaller than their actual size by a light transmission method. Also, for low-density objects, a high proportion of the scattered light energy is within a small angle of the incident beam, which may also be relevant for measurements with aggregates.Using the 'turbidity fluctuation' technique as an example, it is shown how the apparent size of hydroxide flocs depends mainly on the included impurity particles, rather than the hydroxide precipitate itself. Results using clay suspensions with hydrolyzing coagulants and under are discussed.

  14. DRAG ON SUBMICRON NANOPARTICLE AGGREGATES

    Institute of Scientific and Technical Information of China (English)

    F.; Einar; Kruis

    2005-01-01

    A new procedure was developed for estimating the effective collision diameter of an aggregate composed of primary particles of any size. The coagulation coefficient of two oppositely charged particles was measured experimentally and compared with classic Fuchs theory, including a new method to account for particle non-sphericity. A second set of experiments were performed on well-defined nanoparticle aggregates at different stages of sintering, i.e. from the aggregate to the fully sintered stage. Here, electrical mobility was used to characterize the particle drag. The aggregates are being built from two different size-fractionated nanoparticle aerosols, the non-aggregated particles are discarded by an electrofilter and then they are passed through a furnace at concentrations low enough not to induce coagulation.

  15. Physical and mechanical properties of mortars containing PET and PC waste aggregates.

    Science.gov (United States)

    Hannawi, Kinda; Kamali-Bernard, Siham; Prince, William

    2010-11-01

    Non-biodegradable plastic aggregates made of polycarbonate (PC) and polyethylene terephthalate (PET) waste are used as partial replacement of natural aggregates in mortar. Various volume fractions of sand 3%, 10%, 20% and 50% are replaced by the same volume of plastic. This paper investigates the physical and mechanical properties of the obtained composites. The main results of this study show the feasibility of the reuse of PC and PET waste aggregates materials as partial volume substitutes for natural aggregates in cementitious materials. Despite of some drawbacks like a decrease in compressive strength, the use of PC and PET waste aggregates presents various advantages. A reduction of the specific weight of the cementitious materials and a significant improvement of their post-peak flexural behaviour are observed. The calculated flexural toughness factors increase significantly with increasing volume fraction of PET and PC-aggregates. Thus, addition of PC and PET plastic aggregates in cementitious materials seems to give good energy absorbing materials which is very interesting for several civil engineering applications like structures subjected to dynamic or impact efforts. The present study has shown quite encouraging results and opened new way for the recycling of PC waste aggregate in cement and concrete composites. Copyright © 2010 Elsevier Ltd. All rights reserved.

  16. OPTIMAL MAINTENANCE AND REPLACEMENT OF EXTRACTION MACHINERY

    Institute of Scientific and Technical Information of China (English)

    Suresh P.SETHI; Hong-Mo YEH; Rong ZHANG; Andrew K.S.JARDINE

    2008-01-01

    This paper considers a problem of optimal preventive maintenance and replacement schedule ofequipment devoted to extracting resources from known deposits. Typical examples are oil drills, mine shovels, etc. At most one replacement of the existing machinery by a new one is allowed. The problem is formulated as an optimal control problem subject to the state constraint that the remaining deposit at any given time is nonnegative. We show that the optimal preventive maintenance, production rates, and the replacement and salvage times of the existing machinery and the new one, if required, can be obtained by solving sequentially a series of free-end-point optimal control problems. Moreover, an algorithm based on this result is developed and used to solve two illustrative examples.

  17. Analysis of aggregation of platelets in thrombosis

    Science.gov (United States)

    Ahuja, Suresh

    Platelets are key players in thrombus formation by first rolling over collagen bound von Willebrand factor followed by formation of a stable interaction with collagen. The first adhered platelets bind additional platelets until the whole injury is sealed off by a platelet aggregate. The coagulation system stabilizes the formed platelet plug by creating a tight fibrin network, and then wound contraction takes place because of morphological changes in platelets. Coagulation takes place by platelet activation and aggregation mainly through fibrinogen polymerization into fibrin fibers. The process includes multiple factors, such as thrombin, plasmin, and local shear-rate which regulate and control the process. Coagulation can be divided into two pathways: the intrinsic pathway and the extrinsic pathway. The intrinsic pathway is initiated by the exposure of a negatively charged. It is able to activate factor XII, using a complex reaction that includes prekallikrein and high-molecular-weight kininogen as cofactors.. Thrombin is the final enzyme that is needed to convert fibrinogen into fibrin. The extrinsic pathway starts with the exposure of tissue factor to the circulating blood, which is the major initiator of coagulation. There are several feedback loops that reinforce the coagulation cascade, resulting in large amounts of thrombin. It is dependent on the presence of pro-coagulant surfaces of cells expressing negatively charged phospholipids--which include phosphatidylserine (PS)--on their outer membrane. PS-bearing surfaces are able to increase the efficiency of the reactions by concentrating and co-localizing coagulation factors.. Aggregation of platelets are analyzed and compared to adhesion of platelet to erythrocyte and to endothelial cells. This abstract is replacing MAR16-2015-020003.

  18. Perspectives on Preference Aggregation.

    Science.gov (United States)

    Regenwetter, Michel

    2009-07-01

    For centuries, the mathematical aggregation of preferences by groups, organizations, or society itself has received keen interdisciplinary attention. Extensive theoretical work in economics and political science throughout the second half of the 20th century has highlighted the idea that competing notions of rational social choice intrinsically contradict each other. This has led some researchers to consider coherent democratic decision making to be a mathematical impossibility. Recent empirical work in psychology qualifies that view. This nontechnical review sketches a quantitative research paradigm for the behavioral investigation of mathematical social choice rules on real ballots, experimental choices, or attitudinal survey data. The article poses a series of open questions. Some classical work sometimes makes assumptions about voter preferences that are descriptively invalid. Do such technical assumptions lead the theory astray? How can empirical work inform the formulation of meaningful theoretical primitives? Classical "impossibility results" leverage the fact that certain desirable mathematical properties logically cannot hold in all conceivable electorates. Do these properties nonetheless hold true in empirical distributions of preferences? Will future behavioral analyses continue to contradict the expectations of established theory? Under what conditions do competing consensus methods yield identical outcomes and why do they do so?

  19. Orthogonal flexible Rydberg aggregates

    Science.gov (United States)

    Leonhardt, K.; Wüster, S.; Rost, J. M.

    2016-02-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali-metal atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable nonadiabatic effects. A joint exciton-motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of nonadiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K. Leonhardt et al., Phys. Rev. Lett. 113, 223001 (2014), 10.1103/PhysRevLett.113.223001]. In this article we discuss the underlying complex dynamics in detail, characterize the switch, and derive our isotropic interaction model from a realistic anisotropic one with the addition of a magnetic bias field.

  20. Orthogonal flexible Rydberg aggregates

    CERN Document Server

    Leonhardt, K; Rost, J M

    2015-01-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable non-adiabatic effects. A joint exciton/motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of non-adiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K.~Leonhardt {\\it et al.}, Phys.~Rev.~Lett. {\\bf 113} 223001 (2014)]. In this article we discuss the underlying complex dynamics in detail, characterise the ...

  1. Inspection-replacement policy of system under predictive maintenance

    Institute of Scientific and Technical Information of China (English)

    LIU Bao-you; FANG You-tong; WEI Jin-xiang; WANG Yong-liang

    2007-01-01

    In general, every system is in one of the three states: normal, abnormal, or failure state. When the system is diagnosed as abnormal state, it needs predictive maintenance. If the system fails, an identical new one will replace it. The predictive maintenance cannot make the system "as good as new". Under these assumptions, the reliability index and the inspection-replacement policy of a system were studied. The explicit expression of the reliability index and the average income rate (i.e., the long-runaverage income per unit time) are derived by using probability analysis and vector Markov process method. The criterion of feasibility for the optimal inspection-replacement policy under the maximum average income rate is obtained. The numerical example shows the optimal inspection-replacement policy can raise the average income rate when the optimal inspection-replacement policy is feasible.

  2. Comparative Analysis of Data Aggregation Algorithms Under Various Architectural Models in Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Anitha C L

    2014-10-01

    Full Text Available Wireless sensor network has emerged as a promising technique that revolutionary the way of sensing information. Dense deployed sensor nodes in a specific region are likely to transfer redundant data to the base station. This increases the communication overhead and affects network lifetime. Since energy conservation is the key issue in wireless sensor network, data aggregation should be incorporated in order to save energy. The main aim of data aggregation technique is to collect and aggregate data in an energy efficient manner so that network lifetime is enhanced. In this paper, authors present state of the research by summarizing the work on data aggregation algorithms that has already been published and by highlighting the performance characteristics that are being addressed. The performance comparison of clustered based data aggregation, chain based data aggregation, tree based data aggregation and grid based data aggregation algorithms have been analyzed using NS-2 for various parameters.

  3. Statistical mixing and aggregation in Feller diffusion

    Science.gov (United States)

    Anteneodo, C.; Duarte Queirós, S. M.

    2009-10-01

    We consider Feller mean-reverting square-root diffusion, which has been applied to model a wide variety of processes with linearly state-dependent diffusion, such as stochastic volatility and interest rates in finance, and neuronal and population dynamics in the natural sciences. We focus on the statistical mixing (or superstatistical) process in which the parameter related to the mean value can fluctuate—a plausible mechanism for the emergence of heavy-tailed distributions. We obtain analytical results for the associated probability density function (both stationary and time-dependent), its correlation structure and aggregation properties. Our results are applied to explain the statistics of stock traded volume at different aggregation scales.

  4. Mechanical and durability properties of fly ash geopolymer concrete containing recycled coarse aggregates

    OpenAIRE

    2016-01-01

    This paper presents mechanical and durability properties of geopolymer concrete containing recycled coarse aggregate (RCA). The RCA is sourced from local construction and demolition (C&D) waste in Perth, Australia. The RCA is used as a partial replacement of natural coarse aggregate (NCA) in geopolymer concrete at 15%, 30% and 50% by wt. which corresponds to series two, three and four, respectively, while the geopolymer concrete containing 100% NCA is control and is considered as the first se...

  5. Pore Structure and Influence of Recycled Aggregate Concrete on Drying Shrinkage

    OpenAIRE

    Yuanchen Guo; Jueshi Qian; Xue Wang

    2013-01-01

    Pore structure plays an important role in the drying shrinkage of recycled aggregate concrete (RAC). High-precision mercury intrusion and water evaporation were utilized to study the pore structure of RAC, which has a different replacement rate of recycled concrete aggregate (RCA), and to analyze its influence on drying shrinkage. Finally, a fractal-dimension calculation model was established based on the principles of mercury intrusion and fractal-geometry theory. Calculations were performed...

  6. Porosity of the recycled concrete with substitution of recycled concrete aggregate. An experimental study

    OpenAIRE

    Gómez Soberón, José Manuel Vicente

    2002-01-01

    In this paper, we present the experimental analysis of samples of recycled concrete (RC) with replacement of natural aggregate (NA) by recycled aggregate originating from concrete (RCA). The results of the tests of mechanical properties of RC were used for comparison with tests of mercury intrusion porosimetry (MIP), in which the distribution of the theoretical pore radius, critical pore ratio, the surface area of the concrete, threshold ratio and average pore radius were studied at ages of 7...

  7. The effect of blast furnace slag on the self-compactability of pumice aggregate lightweight concrete

    Indian Academy of Sciences (India)

    Murat Kurt; Türkay Kotan; Muhammed Said Gül; Rüstem Gül; Abdulkadir Cüneyt Aydin

    2016-02-01

    This paper presents the results of an experimental study of the effects of blast furnace slag, different water/(cement+mineral additive) ratios and pumice aggregates on some physical and mechanical properties of self-compacting lightweight aggregate concrete. In this study, pumice was used as lightweight aggregate. Several properties of self-compacting pumice aggregate lightweight concretes, such as unit weight, flow diameter, T50 time, flow diameter after an hour, V-funnel time, and L-box tests, 7, 28, 90 and 180-day compressive strength, 28-day splitting tensile strength, dry unit weight, water absorption, thermal conductivity and ultrasonic pulse velocity tests, were conducted. For this purpose, 18 series of concrete samples were prepared in two groups. In the first group, pumice aggregate at 100% replacement of natural aggregate was used in the production of self-compacting lightweight aggregate concrete with constant w/(c+m) ratios as 0.35, 0.40, and 0.45 by weight. Furthermore, as a second group, pumice aggregate was used as a replacement of natural aggregate, at the levels of 0, 20, 40, 60, 80, and 100% by volume. Flow diameters, T50 times, paste volumes, 28-day compressive strengths, dry unit weights, thermal conductivities and ultrasonic pulse velocity of self-compacting lightweight aggregate concrete were obtained over the range of 600–770 mm, 3–9 s, 435–540 l/m3, 10.6–65.0 MPa, 845–2278 kg/m3, 0.363–1.694 W/mK and 2617–4770 m/s respectively, which satisfies not only the strength requirement of semistructural lightweight concrete but also the flowing ability requirements and thermal conductivity requirements of self-compacting lightweight aggregate concrete.

  8. Stripping in hot mix asphalt produced by aggregates from construction and demolition waste.

    Science.gov (United States)

    Pérez, I; Pasandín, A R; Gallego, J

    2012-01-01

    This paper analyses the effect of water on the durability of hot asphalt mixtures made with recycled aggregates from construction and demolition debris. Indirect tensile stress tests were carried out to evaluate stripping behaviour. The mixtures tested were fabricated with 0, 20, 40 and 60% recycled aggregates. Two types of natural aggregates were used: schist and calcite dolomite. An increase in the percentage of recycled aggregates was found to produce a decrease in the tensile stress ratio of the hot asphalt mixtures. To study this phenomenon, two and three factor analyses of variance (ANOVA) were performed with indirect tensile stress being used as the dependent variable. The factors studied were the percentage of recycled aggregates (0, 20, 40 and 60%), the moisture state (dry, wet) and the type of natural aggregate (schist, calcite). On the basis of the ANOVA results, it was found that the most important factor affecting resistance was the moisture state (dry, wet) of the specimens. The percentage of recycled aggregate also affected indirect tensile stress, especially in the dry state. The type of natural aggregate did not have a significant effect on indirect tensile stress. The hot asphalt mixture specimens made with different percentages of recycled aggregates from construction and demolition debris and of natural quarry aggregates showed poor stripping behaviour. This stripping behaviour can be related to both the poor adhesion of the recycled aggregates and the high absorption of the mortar of cement adhered to them.

  9. Iron replacement therapy

    DEFF Research Database (Denmark)

    Nielsen, Ole Haagen; Coskun, Mehmet; Weiss, Günter

    2016-01-01

    PURPOSE OF REVIEW: Approximately, one-third of the world's population suffers from anemia, and at least half of these cases are because of iron deficiency. With the introduction of new intravenous iron preparations over the last decade, uncertainty has arisen when these compounds should be admini...... treatment, when to follow-up for relapse, which dosage and type of therapy should be recommended or not recommended, and if some patients should not be treated....... be administered and under which circumstances oral therapy is still an appropriate and effective treatment. RECENT FINDINGS: Numerous guidelines are available, but none go into detail about therapeutic start and end points or how iron-deficiency anemia should be best treated depending on the underlying cause...... of iron deficiency or in regard to concomitant underlying or additional diseases. SUMMARY: The study points to major issues to be considered in revisions of future guidelines for the true optimal iron replacement therapy, including how to assess the need for treatment, when to start and when to stop...

  10. Study on conversion relationships of compressive strength indexes for recycled lightweight aggregate concrete

    Science.gov (United States)

    Zhang, Xiang-gang; Yang, Jian-hui; Kuang, Xiao-mei

    2017-01-01

    In order to study cube compressive strength and axial compressive strength of recycled lightweight aggregate concrete(RLAC), and conversion relationship between the two, with the replacement rate of recycled lightweight coarse aggregate as change parameters, 15 standard cube test specimens and 15 standard prism test specimens were produced to carry out the test. Then compressive strength of test specimens were measured, and the law of different replacement rate of recycled lightweight coarse aggregate influencing compressive strength of RLAC was analyzed, as the method of statistical regression adopted, the conversion relationships between of cube compressive strength and axial compressive strength of RLAC was obtained. It is shown that compressive strength of RLAC are lower than compressive strength of ordinary concrete; and that compressive strength of RLAC gradually decreases as replacement rate of recycled lightweight coarse aggregate increases; as well as, the conversion relationship between axial compressive strength and cube compressive strength of RLAC is different from ordinary concrete; based on the experimental data, conversion relationship formula between compressive strength indexes of RLAC was established. It is suggested that the replacement rate of recycled lightweight aggregate should be controlled within 25%.

  11. Environmental performance and mechanical analysis of concrete containing recycled asphalt pavement (RAP) and waste precast concrete as aggregate.

    Science.gov (United States)

    Erdem, Savaş; Blankson, Marva Angela

    2014-01-15

    The overall objective of this research project was to investigate the feasibility of incorporating 100% recycled aggregates, either waste precast concrete or waste asphalt planning, as replacements for virgin aggregates in structural concrete and to determine the mechanical and environmental performance of concrete containing these aggregates. Four different types of concrete mixtures were designed with the same total water cement ratio (w/c=0.74) either by using natural aggregate as reference or by totally replacing the natural aggregate with recycled material. Ground granulated blast furnace slag (GGBS) was used as a mineral addition (35%) in all mixtures. The test results showed that it is possible to obtain satisfactory performance for strength characteristics of concrete containing recycled aggregates, if these aggregates are sourced from old precast concrete. However, from the perspective of the mechanical properties, the test results indicated that concrete with RAP aggregate cannot be used for structural applications. In terms of leaching, the results also showed that the environmental behaviour of the recycled aggregate concrete is similar to that of the natural aggregate concrete. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Mactaquac intake tendons removal and replacement

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, I. [NB Power Generation Corp., Mactaquac Generating Station, Keswick Ridge, NB (Canada); Mee, A. [Hatch Energy, Niagara Falls, ON (Canada)

    2007-07-01

    In 1988 and 1989, multi-strand tendons were installed in the intake structure of the Mactaquac generating station. In order to control displacements caused by alkali aggregate reaction (AAR), they were installed in preparation for a slot cutting program in the intake structure to guard against the possibility of a sliding failure of a section of the structure along a plane coincident with the bottom of the water passage. Unique problems for the designers were present in the expansion affect of AAR that were compounded by field conditions that resulted in further difficulties. For example, concrete expansion required the installation of a thick shim pack under the upper anchor head and the periodic testing of the tendons. Once tested, shims could be gradually removed to maintain the correct load over the life of the tendon. However, during the first round of testing and de-stressing five years after the original installation, it was found that some of the tendons had already failed. Over half of the tendons have been replaced in the 20 years since the installation. This paper discussed the original design considerations and examined the conditions that contributed to the premature failure of the tendons. It outlined the history of tendon testing procedures, tendon failure modes and tendon replacement methods. Specifically, the paper discussed the remedial techniques that were employed and the iterations that lead to the current repair approach, while considering the unique field conditions. The application of various corrosion protection schemes and installation and testing methodologies were discussed. It was concluded that tendons were successfully installed in numerous concrete dams around the world but have needed replacement for a variety of reasons. 1 ref., 10 figs.

  13. Exploiting BSA to Inhibit the Fibrous Aggregation of Magnetic Nanoparticles under an Alternating Magnetic Field

    Directory of Open Access Journals (Sweden)

    Ning Gu

    2013-03-01

    Full Text Available The alternating magnetic field was discovered to be capable of inducing the fibrous aggregation of magnetic nanoparticles. However, this anisotropic aggregation may be unfavorable for practical applications. Here, we reported that the adsorption of BSA (bovine serum albumin on the surfaces of magnetic nanoparticles can effectively make the fibrous aggregation of γ-Fe2O3 nanoparticles turn into a more isotropic aggregation in the presence of the alternating magnetic field. Also, the heating curves with and without BSA adsorption under different pH conditions were measured to show the influence of the colloidal aggregation states on the collective calorific behavior of magnetic nanoparticles.

  14. Self-Construction of Aggregation Tree for Gathering Mobile Data in Wireless Sensor Network

    Science.gov (United States)

    Lee, Sangbin; Kim, Songmin; Kim, Sungjun; Ko, Doohyun; Kim, Bumjin; An, Sunshin

    A network of sensors can be used to obtain state based data from the area in which they are deployed. To reduce costs, the data sent via intermediate sensors to a sink are often aggregated. In this letter, we introduce Self-Construction of Aggregation Tree (SCAT) scheme which uses a novel data aggregation scheme utilizing the knowledge of the mobile node and the infrastructure (static node tree) in gathering the data from the mobile node. The static nodes can construct a near- optimal aggregation tree by themselves, using the knowledge of the mobile node, which is a process similar to forming the centralized aggregation tree.

  15. Study on the behaviour of rubber aggregates concrete beams using analytical approach

    Directory of Open Access Journals (Sweden)

    Priyanka Asutkar

    2017-02-01

    Full Text Available Concrete is one the most extensively used construction material all over the world. Many scientists and researchers are in quest for developing alternate construction material that are environment friendly and contribute towards sustainable development. Huge amount of rubber tyres waste is being generated day by day which creates the disposal problem and has many environmental issues. As this scrap rubber waste is an elastic material having less specific gravity, energy absorbent material can be used as a replacement material for obtaining lightweight concrete. In present study an attempt is made to partially replace the rubber aggregates by coarse aggregates in concrete and to study its impact on properties of concrete. A modified concrete is prepared by replacing coarse aggregates in concrete with rubber aggregates by varying the replacement proportion from 0% to 20% with increment of 5%. 3 cubes for each percentage of replacement are casted and tested after 28th days of curing. The physiomechanical properties like density, compressive strength and elastic properties of modified concrete are determined from concrete cubes experimentally and further stresses and displacement at every 50 mm depth of beams are determined analytically by method of initial functions (MIF. MIF is an analytical method in which elastic properties and theoretical loads are used to analyse the beams without conducting any experimental programme. The analytical results by MIF are compared with bending theory.

  16. Aggregating and Disaggregating Flexibility Objects

    DEFF Research Database (Denmark)

    Siksnys, Laurynas; Valsomatzis, Emmanouil; Hose, Katja

    2015-01-01

    In many scientific and commercial domains we encounter flexibility objects, i.e., objects with explicit flexibilities in a time and an amount dimension (e.g., energy or product amount). Applications of flexibility objects require novel and efficient techniques capable of handling large amounts...... energy data management and discuss strategies for aggregation and disaggregation of flex-objects while retaining flexibility. This paper further extends these approaches beyond flex-objects originating from energy consumption by additionally considering flex-objects originating from energy production...... and aiming at energy balancing during aggregation. In more detail, this paper considers the complete life cycle of flex-objects: aggregation, disaggregation, associated requirements, efficient incremental computation, and balance aggregation techniques. Extensive experiments based on real-world data from...

  17. Dependability in Aggregation by Averaging

    CERN Document Server

    Jesus, Paulo; Almeida, Paulo Sérgio

    2010-01-01

    Aggregation is an important building block of modern distributed applications, allowing the determination of meaningful properties (e.g. network size, total storage capacity, average load, majorities, etc.) that are used to direct the execution of the system. However, the majority of the existing aggregation algorithms exhibit relevant dependability issues, when prospecting their use in real application environments. In this paper, we reveal some dependability issues of aggregation algorithms based on iterative averaging techniques, giving some directions to solve them. This class of algorithms is considered robust (when compared to common tree-based approaches), being independent from the used routing topology and providing an aggregation result at all nodes. However, their robustness is strongly challenged and their correctness often compromised, when changing the assumptions of their working environment to more realistic ones. The correctness of this class of algorithms relies on the maintenance of a funda...

  18. 39 CFR 777.24 - Replacement housing payments.

    Science.gov (United States)

    2010-07-01

    ... replacement dwelling). They include: (1) Legal, closing, and related costs, including those for title search... assurance of title. (7) Escrow agent's fee. (8) State revenue or documentary stamps, sales or transfer...

  19. Foam stabilization by solid particle aggregates

    Energy Technology Data Exchange (ETDEWEB)

    Guignot, S.; Faure, S. [CEA Marcoule, Lab. des Procedes Avances de Decontamination, 30 (France); Pitois, O. [UniversiteParis-Est Marne-La-Valle, Lab. Physique des Materiaux Divises et des Interfaces (LPMDI), 77 - Marne la Vallee (France)

    2008-07-01

    During the dismantling of nuclear facilities, radioactive deposits on exposed areas are removed and solubilized by successive rinses of reactive liquid. Using this liquid in a foam state reduces the amount of resulting wastes. During the required decontamination time (1 to 5 hours) the foam has to be sufficiently wet (1). In the Laboratory of Advanced Processes for Decontamination, new formulations are currently studied to slow down the drainage kinetics of these foams, by adding colloidal particles of hydrophilic fumed silica into the classical mixtures of well-defined non ionic foaming surfactants previously used (2). The objective of our study is to shed light on the foam surprising stability induced by these particles. The study focuses on drainage of foams generated by air sparging through a suspension lying on a porous glass. The foaming suspensions contain between 0 and 70 g.L-1 of a fumed silica (Aerosil 380) which is well-known to form gels for concentrations above 200 g.L{sup -1}. In the studied solutions this silica builds up into aggregates of dozens of microns, whose volume-averaged mean diameter after sonication is centred around 300 nm. Under gentle stirring, they display no sign of re-aggregation during 24 h. On a free drainage configuration, a foam that contains particles keeps a significant amount of its initial liquid: up to 60 % during up to 5 hours, in contrast to classical foams that drain out all of their liquid in about 20 minutes. From a rheological point of view, the most concentrated suspensions display a yield stress behaviour. This evidences the structuring of the aggregates into a coherent network that might explain the incomplete drainage of the solutions. For the lowest concentrated solutions, such rheological properties have not been observed although the corresponding foams can retain large amount of solution. This suggests that local concentrations of aggregates can rise owing to their retention by foam channels, until they form

  20. Using your shoulder after replacement surgery

    Science.gov (United States)

    Joint replacement surgery - using your shoulder; Shoulder replacement surgery - after ... You have had shoulder replacement surgery to replace the bones of your shoulder joint with artificial parts. The parts include a stem made of metal and a ...

  1. REPLACEMENT CONTROL OF INNOVATION MANAGERS: ORGANIZATIONAL AND ECONOMIC ASPECTS

    Directory of Open Access Journals (Sweden)

    E. V. Gurina

    2011-01-01

    Full Text Available The paper substantiates phases of specialists’ replacement ensuring innovation development of the national economy in Belarus, i.e. managers of innovation activity. Realization of replacement phases is presented within the system consisting of four blocks – objective, managing, controllable and providing. Analysis results of the current state of the innovation activity managers replacement system reveal main problems in interaction of its basic agents. The paper considers solution of specified problems in the context of formation of organizational and economic approaches to managing the innovation activity managers replacement system which presupposes modernization of organizational interrelations between state- run public authorities in the managing block and micro-incentive structures in the controllable block as well as the usage of the process approach in every phase of the replacement process. 

  2. Model for amorphous aggregation processes

    Science.gov (United States)

    Stranks, Samuel D.; Ecroyd, Heath; van Sluyter, Steven; Waters, Elizabeth J.; Carver, John A.; von Smekal, Lorenz

    2009-11-01

    The amorphous aggregation of proteins is associated with many phenomena, ranging from the formation of protein wine haze to the development of cataract in the eye lens and the precipitation of recombinant proteins during their expression and purification. While much literature exists describing models for linear protein aggregation, such as amyloid fibril formation, there are few reports of models which address amorphous aggregation. Here, we propose a model to describe the amorphous aggregation of proteins which is also more widely applicable to other situations where a similar process occurs, such as in the formation of colloids and nanoclusters. As first applications of the model, we have tested it against experimental turbidimetry data of three proteins relevant to the wine industry and biochemistry, namely, thaumatin, a thaumatinlike protein, and α -lactalbumin. The model is very robust and describes amorphous experimental data to a high degree of accuracy. Details about the aggregation process, such as shape parameters of the aggregates and rate constants, can also be extracted.

  3. Study on performance of concrete with over-burnt bricks aggregates and micro-silica admixture

    Science.gov (United States)

    Praveen, K.; Sathyan, Dhanya; Mini, K. M.

    2016-09-01

    Concrete is made by mixing cement, sand, aggregates and water in required proportion, where aggregates occupy the major volume. Addition of aggregates in concrete improves properties of concrete. With the natural resources depleting rapidly, limiting the use of natural resources and enhancing the use of waste materials is very important for sustainable development. Over-burnt bricks are a waste material which cannot be used in construction directly because of their irregular shape and dark colour. Use of over-burnt bricks helps to preserve natural aggregate source. The present study focuses on the effects of microsilica at various percentages as a partial cement replacement in concrete with over-burnt bricks as coarse aggregates. The mechanical properties of hardened concrete such as splitting tensile strength, flexural strength and compressive strength are studied and analyzed.

  4. Applicability of recycled aggregates in concrete piles for soft soil improvement.

    Science.gov (United States)

    Medeiros-Junior, Ronaldo A; Balestra, Carlos Et; Lima, Maryangela G

    2017-01-01

    The expressive generation of construction and demolition waste is stimulating several studies for reusing this material. The improvement of soft soils by concrete compaction piles has been widely applied for 40 years in some Brazilian cities. This technique is used to improve the bearing capacity of soft soils, allowing executing shallow foundations instead of deep foundations. The compaction piles use a high volume of material. This article explored the possibility of using recycled aggregates from construction waste to replace the natural aggregates in order to improve the bearing capacity of the soft soil, regarding its compressive strength. Construction wastes from different stages of a construction were used in order to make samples of concrete with recycled aggregates. The strength of concretes with natural aggregates was compared with the strength of concretes with recycled (fine and coarse) aggregates. Results show that all samples met the minimum compressive strength specified for compaction piles used to improve the bearing capacity of soft soils. The concrete with recycled aggregate from the structural stage had even higher resistances than the concrete with natural aggregates. This behaviour was attributed to the large amount of cementitious materials in the composition of this type of concrete. It was also observed that concrete with recycled fine aggregate has a superior resistance to concrete with recycled coarse aggregate.

  5. Platelet aggregation and quality control of platelet concentrates produced in the Amazon Blood Bank

    Directory of Open Access Journals (Sweden)

    Maria José Dantas Coêlho

    2011-01-01

    Full Text Available BACKGROUND: The study of platelet aggregation is essential to assess in vitro platelet function by different platelet activation pathways. OBJECTIVE: To assess aggregation and biochemical parameters of random platelet concentrates produced at the Fundação HEMOAM using the quality control tests defined by law. METHODS: Whole blood samples from 80 donors and the respective platelet concentrate units were tested. Platelet concentrates were tested (platelet count, aggregation and pH on days 1, 3 and 5 of storage. Additionally a leukocyte count was done only on day 1 and microbiological tests on day 5 of storage. Collagen and adenosine diphosphate were used as inducing agonists for platelet aggregation testing. RESULTS: Donor whole blood had normal aggregation (aggregation with adenosine diphosphate = 67% and with collagen = 78%. The median aggregation in platelet concentrates with adenosine diphosphate was low throughout storage (18% on day 1, 7% on day 3 and 6% on day 5 and the median aggregation with collagen was normal only on day 1 and low thereafter (54.4% on day 1, 20.5% on day 3 and 9% on day 5. CONCLUSION: Although the results were within the norms required by law, platelet concentrates had low aggregation rates. We suggest the inclusion of a functional assessment test for the quality control of platelet concentrates for a more effective response to platelet replacement therapy.

  6. Aggregate of nanoparticles: rheological and mechanical properties

    Directory of Open Access Journals (Sweden)

    Wang Yu

    2011-01-01

    Full Text Available Abstract The understanding of the rheological and mechanical properties of nanoparticle aggregates is important for the application of nanofillers in nanocompoistes. In this work, we report a rheological study on the rheological and mechanical properties of nano-silica agglomerates in the form of gel network mainly constructed by hydrogen bonds. The elastic model for rubber is modified to analyze the elastic behavior of the agglomerates. By this modified elastic model, the size of the network mesh can be estimated by the elastic modulus of the network which can be easily obtained by rheology. The stress to destroy the aggregates, i.e., the yield stress (σy , and the elastic modulus (G' of the network are found to be depended on the concentration of nano-silica (ϕ, wt.% with the power of 4.02 and 3.83, respectively. Via this concentration dependent behavior, we can extrapolate two important mechanical parameters for the agglomerates in a dense packing state (ϕ = 1: the shear modulus and the yield stress. Under large deformation (continuous shear flow, the network structure of the aggregates will experience destruction and reconstruction, which gives rise to fluctuations in the viscosity and a shear-thinning behavior.

  7. Lysozyme Aggregation and Fibrillation Monitored by Dynamic Light Scattering

    Science.gov (United States)

    Nemzer, Louis; Flanders, Bret; Schmit, Jeremy; Sorensen, Christopher

    2012-02-01

    The aggregation of amyloidogenic proteins provides a rich phase space with significant biomedical implications, including a link with several age-related diseases. We employed dynamic light scattering to monitor the aggregation of lysozyme, a model protein, from a monomeric state until the formation of micron-sized fibrils. For an aqueous lysozyme solution buffered at pH 2, the auto-correlation function of the scattered light intensity was found to be well-fit by a single exponential function with decay time τ = 1/(2Dq^2) = 0.25 ms, which corresponds to a mean hydrodynamic radius (RH) of 2.2 nm, very likely generated by monomers. Ethanol (4% v/v final concentration) induced a partial unfolding, to RH = 4.6 nm. The subsequent addition of 70 mM KCl was found to shrink the size back to RH = 2.5 nm, as expected when a denatured protein refolds due to partial screening of the intramolecular repulsion. However, further aggregation was not observed. At pH 4, using a low-salt acetate buffer, more ethanol (10% v/v) was required to initiate unfolding, but once it occurred, larger aggregates formed. These results are consistent with the model that partial unfolding, which exposes beta-motif secondary structure, is a prerequisite for aggregation and fibrillation, but the aggregation fate depends on the protein charge state (pH) and screening (salt concentration).

  8. Markov chain aggregation and its applications to combinatorial reaction networks.

    Science.gov (United States)

    Ganguly, Arnab; Petrov, Tatjana; Koeppl, Heinz

    2014-09-01

    We consider a continuous-time Markov chain (CTMC) whose state space is partitioned into aggregates, and each aggregate is assigned a probability measure. A sufficient condition for defining a CTMC over the aggregates is presented as a variant of weak lumpability, which also characterizes that the measure over the original process can be recovered from that of the aggregated one. We show how the applicability of de-aggregation depends on the initial distribution. The application section is devoted to illustrate how the developed theory aids in reducing CTMC models of biochemical systems particularly in connection to protein-protein interactions. We assume that the model is written by a biologist in form of site-graph-rewrite rules. Site-graph-rewrite rules compactly express that, often, only a local context of a protein (instead of a full molecular species) needs to be in a certain configuration in order to trigger a reaction event. This observation leads to suitable aggregate Markov chains with smaller state spaces, thereby providing sufficient reduction in computational complexity. This is further exemplified in two case studies: simple unbounded polymerization and early EGFR/insulin crosstalk.

  9. Visual Image Sensor Organ Replacement

    Science.gov (United States)

    Maluf, David A.

    2014-01-01

    This innovation is a system that augments human vision through a technique called "Sensing Super-position" using a Visual Instrument Sensory Organ Replacement (VISOR) device. The VISOR device translates visual and other sensors (i.e., thermal) into sounds to enable very difficult sensing tasks. Three-dimensional spatial brightness and multi-spectral maps of a sensed image are processed using real-time image processing techniques (e.g. histogram normalization) and transformed into a two-dimensional map of an audio signal as a function of frequency and time. Because the human hearing system is capable of learning to process and interpret extremely complicated and rapidly changing auditory patterns, the translation of images into sounds reduces the risk of accidentally filtering out important clues. The VISOR device was developed to augment the current state-of-the-art head-mounted (helmet) display systems. It provides the ability to sense beyond the human visible light range, to increase human sensing resolution, to use wider angle visual perception, and to improve the ability to sense distances. It also allows compensation for movement by the human or changes in the scene being viewed.

  10. [Animal experiment, can we replace?

    Science.gov (United States)

    Combrisson, H

    2017-09-01

    Animal experiment is a subject of controversies. Some people, defenders of animals, think that it is not acceptable to use for scientific purposes at the risk of making them suffer or assert that the results obtained with animals are not transposable in the human beings. Others, in particular researchers in biology or medicine, think that the animal models are essential for the biomedical search. This confrontation of the opinions bases largely on an evolution of the place of animals in our society. The regulations authorize the use of animals for scientific purposes but oblige to make it under restrictive conditions. The application of 3Rs - replacement, reduction, and refinement - expressed in 1959 by Russel and Burch is an ethical guide to improve the welfare of animals in research. The alternative methods do not allow, in the present state of the knowledge, to answer all the scientific questions in biology and medicine research. They are, most of the time, complementary methods of the in vivo methods. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. How Would You Like to Aggregate Your Temporal Data?

    DEFF Research Database (Denmark)

    Böhlen, M. H.; Gamper, J.; Jensen, Christian Søndergaard

    2006-01-01

    and query languages have been proposed. Motivated in part by the emergence of non-traditional data management applications and the increasing proliferation of temporal data, this paper puts focus on the aggregation of temporal data. In particular, it provides a general framework of temporal aggregation...... concepts, and it discusses the abilities of five approaches to the design of temporal query languages with respect to temporal aggregation. Rather than providing focused, polished results, the paper?s aim is to explore the inherent support for temporal aggregation in an informal manner that may serve......Real-world data management applications generally manage temporal data, i.e., they manage multiple states of time-varying data. Many contributions have been made by the research community for how to better model, store, and query temporal data. In particular, several dozen temporal data models...

  12. Magnetic microparticle aggregation for viscosity determination by MR.

    Science.gov (United States)

    Hong, Rui; Cima, Michael J; Weissleder, Ralph; Josephson, Lee

    2008-03-01

    Micron-sized magnetic particles were induced to aggregate when placed in homogeneous magnetic fields, like those of MR imagers and relaxometers, and then spontaneously returned to their dispersed state when removed from the field. Associated with the aggregation and dispersion of the magnetic particles were time-dependent increases and decreases in the spin-spin relaxation time (T2) of the water. Magnetic nanoparticles, with far smaller magnetic moments per particle, did not undergo magnetically induced aggregation and exhibited time-independent values of T2. The rate of T2 change associated with magnetic microparticle aggregation was used to determine the viscosity of liquid samples, providing a method that can be of particular advantage for determining the viscosity of small volumes of potentially biohazardous samples of blood or blood plasma. (c) 2008 Wiley-Liss, Inc.

  13. Magnetic Microparticle Aggregation For Viscosity Determination By Magnetic Resonance

    Science.gov (United States)

    Hong, Rui; Cima, Michael J.; Weissleder, Ralph; Josephson, Lee

    2009-01-01

    Micron-sized magnetic particles were induced to aggregate when placed in homogeneous magnetic fields, like those of magnetic resonance (MR) imagers and relaxometers, and then spontaneously returned to their dispersed state when removed from the field. Associated with the aggregation and dispersion of the magnetic particles were time dependent increases and decreases in the spin-spin relaxation time (T2) of the water. Magnetic nanoparticles, with far smaller magnetic moments per particle, did not undergo magnetically induced aggregation, and exhibited time independent values of T2. The rate of T2 change associated with magnetic micro-particle aggregation was used to determine the viscosity of liquid samples, providing a method that can be of particular advantage for determining the viscosity of small volumes of potentially biohazardous samples of blood or blood plasma. PMID:18306403

  14. Dynamics of Dust Aggregates in a Complex Plasma

    Science.gov (United States)

    Davis, Allen; Carmona Reyes, Jorge; Matthews, Lorin; Hyde, Truell

    2012-10-01

    Charged dust aggregates play an important role in many astrophysical phenomena, such as early stages of protostellar and protoplanetary growth, the dynamics of planetary rings and cometary tails, and the formation of noctilucent clouds in earth's upper atmosphere. Dust is also expected to be an unwanted byproduct in the operation of plasma fusion devices, such as ITER. In all of these environments, direct study of the dust aggregates in their in situ environment is extremely difficult, if not impossible. As a model for these complex plasma environments, dust aggregates are formed in a laboratory plasma as monodisperse spheres are accelerated in a self-excited dust density wave. Individual dust particles are perturbed using a diode pumped solid state laser (Coherent VERDI) with their motions recorded by a high-speed camera at 1000 fps. Analysis of the particle motion allows determination of the aggregate characteristics which determine the grain dynamics, such as charge, mass, and gas drag.

  15. Educating My Replacement

    Science.gov (United States)

    Tarter, Jill

    , in partnership with the dedicated teachers out there, I think I can help promote the critical thinking skills and scientific literacy of the next generation of voters. Hopefully, I can also help train my replacement to be a better scientist, capable of seizing all the opportunities generated by advances in technology and our improved understanding of the universe to craft search strategies with greater probability of success than those I have initiated.

  16. 持续性肾脏替代治疗抗凝技术的应用%The current state and prospect of continuous renal replacement treatment anticoagulation technique

    Institute of Scientific and Technical Information of China (English)

    管向东; 孙冠青; 陈娟

    2012-01-01

    Continuous renal replacement treatment (CRRT) is a common organ function support ive technique in the field of Critical Care Medicine. Since sepsis patients are always combined with hemodynamic instability and coagulation dysfunction , anticoagulation therapy has been an indispensable component part in CRRT for sepsis patients. Anticoagulation therapy enables to slow or reduce the clottings in pipeline and/or filter so as to prolong its life,improve the efficacy of CRRT treatment, and reduce the loss of blood components and thrombosis under pathological state. So far,the common CRRT anticoagulation drugs include heparin,antithrombin,low molecular weight heparin (LMWH) and/or hyparinoids from animal organs, II factor antagonists, nafamostat, sodium citrate and antiplatelet agents. Coagulation function should be regularly monitored in the process of CRRT anticoagulation treatment. Under the circumstance of anticoagulation taboo, heparin-saline priming, predilution and hydrophilic filter can be used to reduce the clottings in pipeline and/or filter.%持续性肾脏替代治疗(CRRT)是重症医学领域常用的器官功能支持技术.由于脓毒症患者常合并血流动力学不稳定及凝血功能障碍,抗凝技术已成为脓毒症患者CRRT过程中必不可少的组成部分.抗凝技术能延缓或减少管路和(或)滤器的凝血,延长其寿命,提高CRRT治疗效率,减少血液成分的丢失及病理状态下的血栓形成.目前常用的CRRT抗凝药物包括肝素、抗凝酶、低分子肝素和(或)肝素类似物、Ⅱ因子拮抗剂、萘莫斯他、枸橼酸钠及抗血小板药物.CRRT抗凝治疗过程中需动态监测凝血功能等指标.在抗凝禁忌的情况下,可用肝素盐水浸泡、前稀释及选择高亲水性滤器等方法减少管路和(或)滤器凝血.

  17. Probabilistic prediction models for aggregate quarry siting

    Science.gov (United States)

    Robinson, G.R.; Larkins, P.M.

    2007-01-01

    Weights-of-evidence (WofE) and logistic regression techniques were used in a GIS framework to predict the spatial likelihood (prospectivity) of crushed-stone aggregate quarry development. The joint conditional probability models, based on geology, transportation network, and population density variables, were defined using quarry location and time of development data for the New England States, North Carolina, and South Carolina, USA. The Quarry Operation models describe the distribution of active aggregate quarries, independent of the date of opening. The New Quarry models describe the distribution of aggregate quarries when they open. Because of the small number of new quarries developed in the study areas during the last decade, independent New Quarry models have low parameter estimate reliability. The performance of parameter estimates derived for Quarry Operation models, defined by a larger number of active quarries in the study areas, were tested and evaluated to predict the spatial likelihood of new quarry development. Population density conditions at the time of new quarry development were used to modify the population density variable in the Quarry Operation models to apply to new quarry development sites. The Quarry Operation parameters derived for the New England study area, Carolina study area, and the combined New England and Carolina study areas were all similar in magnitude and relative strength. The Quarry Operation model parameters, using the modified population density variables, were found to be a good predictor of new quarry locations. Both the aggregate industry and the land management community can use the model approach to target areas for more detailed site evaluation for quarry location. The models can be revised easily to reflect actual or anticipated changes in transportation and population features. ?? International Association for Mathematical Geology 2007.

  18. Ash Aggregates in Proximal Settings

    Science.gov (United States)

    Porritt, L. A.; Russell, K.

    2012-12-01

    Ash aggregates are thought to have formed within and been deposited by the eruption column and plume and dilute density currents and their associated ash clouds. Moist, turbulent ash clouds are considered critical to ash aggregate formation by facilitating both collision and adhesion of particles. Consequently, they are most commonly found in distal deposits. Proximal deposits containing ash aggregates are less commonly observed but do occur. Here we describe two occurrences of vent proximal ash aggregate-rich deposits; the first within a kimberlite pipe where coated ash pellets and accretionary lapilli are found within the intra-vent sequence; and the second in a glaciovolcanic setting where cored pellets (armoured lapilli) occur within Diamond Mine, Canada, are the residual deposits within the conduit and vent of the volcano and are characterised by an abundance of ash aggregates. Coated ash pellets are dominant but are followed in abundance by ash pellets, accretionary lapilli and rare cored pellets. The coated ash pellets typically range from 1 - 5 mm in diameter and have core to rim ratios of approximately 10:1. The formation and preservation of these aggregates elucidates the style and nature of the explosive phase of kimberlite eruption at A418 (and other pipes?). First, these pyroclasts dictate the intensity of the kimberlite eruption; it must be energetic enough to cause intense fragmentation of the kimberlite to produce a substantial volume of very fine ash (sustained plume attended by concomitant production of pyroclastic density currents. The size and internal structure of the armoured lapilli provide constraints on the nature of the initial explosive phase of eruption at Kima'Kho. Their proximity to the vent also indicates rapid aggregation within the eruption plume. Within both sequences rapid aggregation of ash particles occurred in proximity to the vent. However, the conditions were substantially different leading to the production of armoured

  19. [Ascending aorta replacement late after aortic valve replacement].

    Science.gov (United States)

    Hayashi, Yasunari; Ito, Toshiaki; Maekawa, Atsuo; Sawaki, Sadanari; Fujii, Genyo; Hoshino, Satoshi; Tokoro, Masayoshi; Yanagisawa, Junji

    2013-07-01

    Replacement of the asceding aorta is indicated in patients undergoing aortic valve replacement( AVR), if the diameter of the ascending aorta is greater than 5.0 cm. If the diameter of the asceding aorta is from 4.0 to 5.0 cm, it was arguable whether replacement of the ascending aorta should be performed. Nine patients who underwent reoperative ascending aorta replacement after AVR were reviewed retrospectively. Reoperation on the asending aorta replacement was performed 11.8±7.2 years (range 1y5m~23y3m) after AVR. Mean patient age was 69.9±6.3 (range 60~81). In 2 cases, reoperations were performed early year after AVR. Although ascending aorta was dilated at the 1st operation, replacement wasn't performed for the age and minimally invasive cardiac surgery (MICS). In 3 cases, reoperations were performed more than 10 years later. On these cases, ascending aorta aneurysm and dissection occurred with no pain and were pointed out by computed tomography(CT) or ultrasonic cardiogram(UCG). We think that patients with dilatation of the ascending aorta should undergo AVR and aorta replacement at the 1st operation regardness of age. It is important that patients who underwent AVR should undergo a regular checkup on the ascending aorta.

  20. Studies on aggregation-propensities and secondary structural transformations of proteins

    Institute of Scientific and Technical Information of China (English)

    JI Li-Na; GAO Yong-Guang; ZHANG Feng; LI Hong-Tao; HU Hong-Yu; HU Jun

    2005-01-01

    The insoluble and fibrillar aggregates of some proteins are thought to be the pathological cause of neurodegenerative diseases. The aggregation-propensities of different types of proteins were investigated by Thioflavine T fluorescence assay and atomic force microscopy imaging. Then, the structural transformations of the proteins from aqueous state to solid state were studied by circular dichroism spectroscopy. The results indicate that proteins of different secondary structure show variations in their aggregation-propensities, together with their various structural transformations from aqueous state to solid state. Our studies imply that the structural transformation of proteins from solution to solid state is closely associated with their aggregation-propensities, which will provide insight into the molecular mechanism of protein aggregation in neurodegenerative diseases.

  1. Monitoring the Aggregation of Dansyl Chloride in Acetone through Fluorescence Measurements

    Institute of Scientific and Technical Information of China (English)

    FANG,Yu; YIN,Yi-Qing; 等

    2002-01-01

    The aggregation of dansyl chloride (DNS-Cl) in acetone has been studied in detail by steady-state fluorescence techniques.It has been demonstrated that DNS-Cl is stable in acetone during purification and aggregation study processes.The aggregates are not solvolyzed in acetone,and do not take part n any chemical reactions either.It has been found that DNS-Cl tends to aggregate even when its concentration is much lower than its solubility in acetone.The aggregation is reversible,and both the aggregation and the deaggregation are very slow processes.Introduction of SDS has a positive effect upon the formation and stabilization of the aggregates.

  2. Hierarchical organization in aggregates of protein molecules

    DEFF Research Database (Denmark)

    Bohr, Henrik; Kyhle, Anders; Sørensen, Alexis Hammer

    1997-01-01

    The aggregation of proteins into small clusters is studied by atomic force and electron microscopy. Scaling laws and fractal behaviour in the growth of the aggregates and in the correlation between aggregates is seen. A phase diagram of the aggregation process where the protonic concentration...

  3. A Functional Reference Architecture for Aggregators

    DEFF Research Database (Denmark)

    Bondy, Daniel Esteban Morales; Heussen, Kai; Gehrke, Oliver;

    2015-01-01

    Aggregators are considered to be a key enabling technology for harvesting power system services from distributed energy resources (DER). As a precondition for more widespread use of aggregators in power systems, methods for comparing and validating aggregator designs must be established. This paper...... proposes a functional reference architecture for aggregators to address this requirement....

  4. Fractal Aggregates in Tennis Ball Systems

    Science.gov (United States)

    Sabin, J.; Bandin, M.; Prieto, G.; Sarmiento, F.

    2009-01-01

    We present a new practical exercise to explain the mechanisms of aggregation of some colloids which are otherwise not easy to understand. We have used tennis balls to simulate, in a visual way, the aggregation of colloids under reaction-limited colloid aggregation (RLCA) and diffusion-limited colloid aggregation (DLCA) regimes. We have used the…

  5. Multi-ring Aggregate Formation in Styrene Polymers

    Institute of Scientific and Technical Information of China (English)

    何炳林; 王国昌; 叶彦春; 栗凤珍; 高传喜

    1994-01-01

    The photophysical properties of some cross-linked/linear styrene polymers are studied.Ithas been further demonstrated that the phenyl multi-ring aggregate forms not only in excited state instyrene/divinylbenzene cross-linked polymers hut also in ground state.Moreover,the similar multi-ring ag-gregate has also been observed in linear polystyrene with structural heterogeneity.These results are ex-plained in terms of "superdense structure" formed by chemical cross-linking and physical gelation,whichcharacterize the morphological heterogeneity in styrene polymers.

  6. An exact approach for aggregated formulations

    DEFF Research Database (Denmark)

    Gamst, Mette; Spoorendonk, Simon; Røpke, Stefan

    optimality cannot be guaranteed by branching on aggregated variables. We present a generic exact solution method to remedy the drawbacks of aggregation. It combines the original and aggregated formulations and applies Benders' decomposition. We apply the method to the Split Delivery Vehicle Routing Problem.......Aggregating formulations is a powerful approach for problems to take on tractable forms. Aggregation may lead to loss of information, i.e. the aggregated formulation may be an approximation of the original problem. In branch-and-bound context, aggregation can also complicate branching, e.g. when...

  7. Electrocatalysts Prepared by Galvanic Replacement

    OpenAIRE

    Athanasios Papaderakis; Ioanna Mintsouli; Jenia Georgieva; Sotiris Sotiropoulos

    2017-01-01

    Galvanic replacement is the spontaneous replacement of surface layers of a metal, M, by a more noble metal, Mnoble, when the former is treated with a solution containing the latter in ionic form, according to the general replacement reaction: nM + mMnoblen+ → nMm+ + mMnoble. The reaction is driven by the difference in the equilibrium potential of the two metal/metal ion redox couples and, to avoid parasitic cathodic processes such as oxygen reduction and (in some cases) hydrogen evolution too...

  8. Erythrocyte aggregation: Basic aspects and clinical importance

    OpenAIRE

    Oğuz K. Başkurt; Meiselman, Herbert J.

    2013-01-01

    Red blood cells (RBC) aggregate to form two- and three-dimensional structures when suspended in aqueous solutions containing large plasma proteins or polymers; this aggregation is reversible and shear dependent (i.e., dispersed at high shear and reformed at low or stasis). The extent of aggregation is the main determinant of low shear blood viscosity, thus predicting an inverse relationship between aggregation and in vivo blood flow. However, the effects of aggregation on hemodynamic mechanis...

  9. Molecular Aggregation in Disodium Cromoglycate

    Science.gov (United States)

    Singh, Gautam; Agra-Kooijman, D.; Collings, P. J.; Kumar, Satyendra

    2012-02-01

    Details of molecular aggregation in the mesophases of the anti-asthmatic drug disodium cromoglycate (DSCG) have been studied using x-ray synchrotron scattering. The results show two reflections, one at wide angles corresponding to π-π stacking (3.32 å) of molecules, and the other at small angles which is perpendicular to the direction of molecular stacking and corresponds to the distance between the molecular aggregates. The latter varies from 35 - 41 å in the nematic (N) phase and 27 -- 32 å in the columnar (M) phase. The temperature evolution of the stack height, positional order correlations in the lateral direction, and orientation order parameter were determined in the N, M, and biphasic regions. The structure of the N and M phases and the nature of the molecular aggregation, together with their dependence on temperature and concentration, will be presented.

  10. Corrosion Behavior of Steel Reinforcement in Concrete with Recycled Aggregates, Fly Ash and Spent Cracking Catalyst

    Directory of Open Access Journals (Sweden)

    Hebé Gurdián

    2014-04-01

    Full Text Available The main strategy to reduce the environmental impact of the concrete industry is to reuse the waste materials. This research has considered the combination of cement replacement by industrial by-products, and natural coarse aggregate substitution by recycled aggregate. The aim is to evaluate the behavior of concretes with a reduced impact on the environment by replacing a 50% of cement by industrial by-products (15% of spent fluid catalytic cracking catalyst and 35% of fly ash and a 100% of natural coarse aggregate by recycled aggregate. The concretes prepared according to these considerations have been tested in terms of mechanical strengths and the protection offered against steel reinforcement corrosion under carbonation attack and chloride-contaminated environments. The proposed concrete combinations reduced the mechanical performance of concretes in terms of elastic modulus, compressive strength, and flexural strength. In addition, an increase in open porosity due to the presence of recycled aggregate was observed, which is coherent with the changes observed in mechanical tests. Regarding corrosion tests, no significant differences were observed in the case of the resistance of these types of concretes under a natural chloride attack. In the case of carbonation attack, although all concretes did not stand the highly aggressive conditions, those concretes with cement replacement behaved worse than Portland cement concretes.

  11. Basic Properties of Concrete Incorporating Recycled Ceramic Aggregate and Ultra-fine Sand

    Institute of Scientific and Technical Information of China (English)

    LIU Fengli; LIU Junhua; MA Baoguo; HUANG Jian; LI Hainan

    2015-01-01

    Recycled ceramic mixed sand (RCMS) was obtained by partially replacing ultra-fine sand with recycled ceramic coarse sand (RCCS). The effects of RCCS replacement rate on the apparent density, workability, compressive strength and splitting tensile strength of recycled ceramic concrete (RCC) were investigated. In addition, the relationship between the water-cement ratio and compressive strength of RCC was also studied. The experimental results indicate that the reusing of recycled ceramic aggregate can improve the cohesiveness and water retentiveness of fresh concrete and benefit the mechanical properties development. When the RCCS replacement rate is not less than 40%, the mechanical properties of RCC are superior to those of the reference concrete. Moreover, when recycled ceramic medium sand was completely used as fine aggregate, the maximum increase in both compressive strength and splitting tensile strength were obtained, comparing with those of reference concrete, the increment ratio was 19.85% and 32.73%, respectively. The microscopic analysis shows that the using of recycled ceramic aggregate can meliorate distinctly the structure of the interfacial transition zone (ITZ) and increase the compaction degree of cement paste. Furthermore, an expression of the compressive strength of RCC and the cement-water ratio is regressed and gains a good linear relativity. It is an effective way to recycle waste ceramic, and the consumption of recycled ceramic aggregate could reach from 26.9%to 47.6%of the total weight of aggregate in producing concrete.

  12. THE ASSESSMENT OF OPPORTUNITIES AND THREATS FOR CHANGES OF TECHNOLOGIES AGGREGATE THROUGH ORDER PARAMETERS

    Directory of Open Access Journals (Sweden)

    T.A. Nelyubina

    2009-09-01

    Full Text Available In this article, author considers a class of technologies aggregates, which can be present as complex socio-economic systems. The order parameters are chosen as instrument of reflect the system integrity of this technologies aggregates. The analysis of aggregates through order parameters permit: to diagnose the state of the system and its life phase, understand the compatibility extent between the current state of system and the assumed modifications in it, understand the nature of attendant risks. It also allows to compare the systems, track the dynamics of order parameters and forecast the trends of the future changes. Author formulates number and definitions of order parameters for this class of technologies aggregates; proposes the assessment method of condition of order parameters for technologies aggregate of region; makes express-assessment of preparedness level of technologies aggregates of some regions to innovation changes.

  13. Environmentalism and natural aggregate mining

    Science.gov (United States)

    Drew, L.J.; Langer, W.H.; Sachs, J.S.

    2002-01-01

    Sustaining a developed economy and expanding a developing one require the use of large volumes of natural aggregate. Almost all human activity (commercial, recreational, or leisure) is transacted in or on facilities constructed from natural aggregate. In our urban and suburban worlds, we are almost totally dependent on supplies of water collected behind dams and transported through aqueducts made from concrete. Natural aggregate is essential to the facilities that produce energy-hydroelectric dams and coal-fired powerplants. Ironically, the utility created for mankind by the use of natural aggregate is rarely compared favorably with the environmental impacts of mining it. Instead, the empty quarries and pits are seen as large negative environmental consequences. At the root of this disassociation is the philosophy of environmentalism, which flavors our perceptions of the excavation, processing, and distribution of natural aggregate. The two end-member ideas in this philosophy are ecocentrism and anthropocentrism. Ecocentrism takes the position that the natural world is a organism whose arteries are the rivers-their flow must not be altered. The soil is another vital organ and must not be covered with concrete and asphalt. The motto of the ecocentrist is "man must live more lightly on the land." The anthropocentrist wants clean water and air and an uncluttered landscape for human use. Mining is allowed and even encouraged, but dust and noise from quarry and pit operations must be minimized. The large volume of truck traffic is viewed as a real menace to human life and should be regulated and isolated. The environmental problems that the producers of natural aggregate (crushed stone and sand and gravel) face today are mostly difficult social and political concerns associated with the large holes dug in the ground and the large volume of heavy truck traffic associated with quarry and pit operations. These concerns have increased in recent years as society's demand for

  14. Aggregating energy flexibilities under constraints

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Pedersen, Torben Bach; Abello, Alberto

    2016-01-01

    The flexibility of individual energy prosumers (producers and/or consumers) has drawn a lot of attention in recent years. Aggregation of such flexibilities provides prosumers with the opportunity to directly participate in the energy market and at the same time reduces the complexity of scheduling...... the energy units. However, aggregated flexibility should support normal grid operation. In this paper, we build on the flex-offer (FO) concept to model the inherent flexibility of a prosumer (e.g., a single flexible consumption device such as a clothes washer). An FO captures flexibility in both time...

  15. Balancing energy flexibilities through aggregation

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Hose, Katja; Pedersen, Torben Bach

    2014-01-01

    One of the main goals of recent developments in the Smart Grid area is to increase the use of renewable energy sources. These sources are characterized by energy fluctuations that might lead to energy imbalances and congestions in the electricity grid. Exploiting inherent flexibilities, which exist...... in both energy production and consumption, is the key to solving these problems. Flexibilities can be expressed as flex-offers, which due to their high number need to be aggregated to reduce the complexity of energy scheduling. In this paper, we discuss balance aggregation techniques that already during...

  16. 温度对大掺量粉煤灰水泥水化C-S-H聚合度的影响%Effect of Temperature on Aggregate States of Hydration Products C-S-H Gel of Cement with High Content of Fly Ash

    Institute of Scientific and Technical Information of China (English)

    于文金; 罗永传; 弓子成; 丁庆军

    2011-01-01

    Effect of curing temperature and temperature variation on silicon-oxy tetrahedron aggregate states of hydra-tion products C-S-H gel of cement with high content of fly ash materials by high-resolution solid "Si NMR,XRD and FT-IR testing techniques. The results show that silicon-oxy tetrahedron aggregate states C-S-H gel and contents of alumi-num-oxy tetrahedron increased and then stabilized with the increase of curing temperature. Curing at normal temperature was good for increasing silicon-oxy tetrahedron aggregate states of CSH gels and contents of aluminum-oxy tetrahedron at the periods from 7 d to 28 d.%采用固体29Si核磁共振、FTIR、XRD测试方法研究了养护温度、温度变化对大掺量粉煤灰水泥基材料水化C-S-H凝胶硅氧四面体聚合程度的影响规律.结果表明:粉煤灰掺量为50%时,C-S-H凝胶硅氧四面体的聚合程度和C-S-H凝胶中铝氧四面体的比例随着养护温度的升高而呈现先增加后稳定的趋势.在7d至28 d龄期阶段,常温养护更加有利于C-S-H凝胶硅氧四面体聚合程度的增加,也更有利于Al原子取代Si原子.

  17. Evaluation of the performance of aggregate in hot-mix asphalt

    CSIR Research Space (South Africa)

    Komba, Julius J

    2014-07-01

    Full Text Available of the aggregate in an asphalt mix was evaluated. The design grading of the asphalt mixes was similar; the only difference being that the coarse granite fractions (6.7 and 9.5 mm) of the asphalt mix of known good field performance were replaced by coarse quartzite...

  18. Effects of surface roughness on plastic strain localization in polycrystalline aggregates

    Directory of Open Access Journals (Sweden)

    Guilhem Yoann

    2014-06-01

    Full Text Available The surface state of mechanical components differs according to applied loadings. Industrial processes may produce specific features at the surface, such as roughness, local hardening, residual stresses or recrystallization. Under fatigue loading, all these parameters will affect the component lifetime, but in different manner. A better understanding of each surface state parameter, separately first and then all combined, will provide a better prediction of fatigue life. The study focuses on the effect of surface roughness. Crystal plasticity finite element computations have been carried out on three-dimensional polycrystalline aggregates with different roughness levels. Local mechanical fields have been analyzed both at the surface and inside the bulk to highlight the competition between crystallography and roughness to impose localization patterns. As soon as surface roughness is strong enough, classical localization bands driven by grains orientation are replaced by localizations patterns driven by the local roughness topology. Nevertheless, this effect tends to decrease gradually under the surface, and it becomes usually negligible after the first layer of grains. The discussion allows us to characterize the influence of the surface state on the local mechanical fields.

  19. Signature of an aggregation-prone conformation of tau

    Science.gov (United States)

    Eschmann, Neil A.; Georgieva, Elka R.; Ganguly, Pritam; Borbat, Peter P.; Rappaport, Maxime D.; Akdogan, Yasar; Freed, Jack H.; Shea, Joan-Emma; Han, Songi

    2017-03-01

    The self-assembly of the microtubule associated tau protein into fibrillar cell inclusions is linked to a number of devastating neurodegenerative disorders collectively known as tauopathies. The mechanism by which tau self-assembles into pathological entities is a matter of much debate, largely due to the lack of direct experimental insights into the earliest stages of aggregation. We present pulsed double electron-electron resonance measurements of two key fibril-forming regions of tau, PHF6 and PHF6*, in transient as aggregation happens. By monitoring the end-to-end distance distribution of these segments as a function of aggregation time, we show that the PHF6(*) regions dramatically extend to distances commensurate with extended β-strand structures within the earliest stages of aggregation, well before fibril formation. Combined with simulations, our experiments show that the extended β-strand conformational state of PHF6(*) is readily populated under aggregating conditions, constituting a defining signature of aggregation-prone tau, and as such, a possible target for therapeutic interventions.

  20. Liver replacement for alpha1-antitrypsin deficiency

    Science.gov (United States)

    Putnam, Charles W.; Porter, Kendrick A.; Peters, Robert L.; Ashcavai, Mary; Redeker, Allan G.; Starzl, Thomas E.

    2010-01-01

    A 16-year-old girl with advanced cirrhosis and severe alpha1-antitrypsin deficiency of the homozygous PiZZ phenotype was treated by orthotopic liver transplantation. After replacement of the liver with a homograft from a donor with the normal PiMM phenotype, the alpha1-antitrypsin concentration in the recipient’s serum rose to normal; it had the PiMM phenotype. Two and a third years later, chronic rejection necessitated retransplantation. Insertion of a homograft from a heterozygous PiMZ donar was followed by the identification of that phenotype in the recipient’s serum. Neither liver graft developed the alpha1-antitrypsin glycoprotein deposits seen with the deficiency state. These observations confirm that this hepatic- based inborn error metabolism is metabolically cured by liver replacement. PMID:320694

  1. Minimally invasive aortic valve replacement

    DEFF Research Database (Denmark)

    Foghsgaard, Signe; Schmidt, Thomas Andersen; Kjaergard, Henrik K

    2009-01-01

    In this descriptive prospective study, we evaluate the outcomes of surgery in 98 patients who were scheduled to undergo minimally invasive aortic valve replacement. These patients were compared with a group of 50 patients who underwent scheduled aortic valve replacement through a full sternotomy....... The 30-day mortality rate for the 98 patients was zero, although 14 of the 98 mini-sternotomies had to be converted to complete sternotomies intraoperatively due to technical problems. Such conversion doubled the operative time over that of the planned full sternotomies. In the group of patients whose...... is an excellent operation in selected patients, but its true advantages over conventional aortic valve replacement (other than a smaller scar) await evaluation by means of randomized clinical trial. The "extended mini-aortic valve replacement" operation, on the other hand, is a risky procedure that should...

  2. The Influence of Crushed Concrete Demolition Waste Aggregates on the Hardening Process of Concrete Mixtures

    Directory of Open Access Journals (Sweden)

    Olga FINOŽENOK

    2013-03-01

    Full Text Available Concrete – complex structure composite material consisting of the components with various structure and size. Not only coarse and fine aggregates are used in concrete production, but also filler aggregates. Aggregates of natural, man-made origin or aggregates, produced from recycled materials, can be utilised in concrete production. Aggregates can be produced from recycled materials by reprocessing of concrete and reinforced concrete waste. The influence of the filler aggregates produced from the crushed concrete waste on the characteristics of binder’s paste, when part of the binder (5; 10; 15; 20; 25; 30 % is replaced by such filler aggregate, is analysed in the research. Concrete mixtures with natural aggregates and crushed concrete waste were selected and concrete mixtures of required consistence were produced during the research. Exothermic reactions take place during the hardening of concrete mixture, at that time the heat is dissipated, which increases the temperature of the concrete sample. Thus the exothermic processes were investigated during the concrete’s mixture hardening period and the temperatures of exothermic reactions were determined.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3833

  3. Interrelationships of glycosylation and aggregation kinetics for Peniophora lycii phytase

    DEFF Research Database (Denmark)

    Høiberg-Nielsen, R.; Fuglsang, C.C.; Arleth, L.

    2006-01-01

    to 10-100 molecules) of the enzyme. The thermodynamic stability of the two forms was also investigated using scanning calorimetry (DSC). It was found that the glycans strongly promoted kinetic stability (i.e., reduced the rate of irreversible denaturation) while leaving the equilibrium denaturation...... and temperature on the aggregation rate. Also, the second virial coefficients (B-22) for the two forms were measured by SLS. These results showed that the aggregation rate of Phy scaled with the concentration of thermally denatured protein. This suggested first-order kinetics with respect to the concentration...... of the thermally denatured state. A similar but less pronounced correlation was found for dgPhy, and it was suggested that while the aggregation process for the deglycosylated form is dominated by denatured protein, it also involves a smaller contribution from associating molecules in the native state...

  4. Different aggregation dynamics of benzene-water mixtures.

    Science.gov (United States)

    Fu, Cen-Feng; Tian, Shan Xi

    2014-10-28

    All-atom molecular dynamics simulations for benzene-water mixtures are performed, aiming to explore the relationship between the microscopic structures and the thermodynamic properties, in particular, the transformation dynamics from the mutually soluble state to the phase-separated state. We find that the molecular aggregation of benzene in the water-rich mixture is distinctly different from that of water in the benzene-rich mixture. This aggregation difference is attributed to the different intermolecular interactions: the clustering of benzene molecules in the water-rich mixture is primarily driven by weak short-distance π-π interactions; while the formation of water clusters in the benzene-rich solution is triggered by long-range dipole-dipole electrostatic interactions. Moreover, the molecular aggregations show double-scaled features: firstly assembling in a quasi-plane at a low concentration, then bulking in three dimensions with an increase in concentration.

  5. Protein aggregation and its impact on product quality.

    Science.gov (United States)

    Roberts, Christopher J

    2014-12-01

    Protein pharmaceutical products are typically active as folded monomers that are composed of one or more protein chains, such as the heavy and light chains in monoclonal antibodies that are a mainstay of current drug pipelines. There are numerous possible aggregated states for a given protein, some of which are potentially useful, while most of which are considered deleterious from the perspective of pharmaceutical product quality and performance. This review provides an overview of how and why different aggregated states of proteins occur, how this potentially impacts product quality and performance, fundamental approaches to control aggregate formation, and the practical approaches that are currently used in the pharmaceutical industry. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Compressive Strength, Pore Size Distribution and Chloride-ion Penetration of Recycled Aggregate Concrete Incorporating Class-F Fly Ash

    Institute of Scientific and Technical Information of China (English)

    KOU Shicong; C S Poon

    2006-01-01

    The effects of fly ash on the compressive strength, pore size distribution ard chloride-ion penetration of recycled aggregate concrete were investigated. Two series of concrete mixtures were prepared. The concrete mixtures in series I had a water-to-binder ratio and a cement content of 0.55 and 410 kg/m3 , respectively. The concrete mixtures in series Ⅱ had a water-to-binder ratio and a cement content of 0.45 and 400 kg/m3 respectively. Recycled aggregate was used as 20% , 50% , and 100% replacements of natural coarse aggregate in the concrete mixtures in both series. In addition, fly ash was used as 0% , 25% and 35% by weight replacements of cement. The results show that the compressive strengths of the concrete decreased as the recycled aggregate and the fly ash contents increased. The total porosity and average porosity diameter of the concrete increased as the recycled aggregate content increased. Furthermore, an increase in the recycled aggregate content decreased the resistance to chloride ion penetration. Nevertheless, the replacement of cement by 25% fly ash improved the resistance to chloride ion penetration and pore diameters and reduced the total porosity of the recycled aggregate concrete.

  7. O2-dependent large electron flow functioned as an electron sink, replacing the steady-state electron flux in photosynthesis in the cyanobacterium Synechocystis sp. PCC 6803, but not in the cyanobacterium Synechococcus sp. PCC 7942.

    Science.gov (United States)

    Hayashi, Ryosuke; Shimakawa, Ginga; Shaku, Keiichiro; Shimizu, Satoko; Akimoto, Seiji; Yamamoto, Hiroshi; Amako, Katsumi; Sugimoto, Toshio; Tamoi, Masahiro; Makino, Amane; Miyake, Chikahiro

    2014-01-01

    To determine whether alternative electron flow (AEF) can replace the photosynthetic electron flow in cyanobacteria, we used an open O2-electrode system to monitor O2-exchange over a long period. In air-grown Synechocystis sp. PCC 6803 (S. 6803(WT)), the quantum yield of PSII, Y(II), held even after photosynthesis was suppressed by CO2 shortage. The S. 6803 mutant, deficient in flavodiiron (FLV) proteins 1 and 3, showed the same phenotype as S. 6803(WT). In contrast, Y(II) decreased in Synechococcus sp. PCC 7942 (S. 7942). These results suggest that AEF functioned as the Y(II) in S. 6803 and replaced the photosynthetic electron flux. In contrast, the activity of AEF in S. 7942 was lower. The affinity of AEF for O2 in S. 6803 did not correspond to those of FLVs in bacteria or terminal oxidases in respiration. AEF might be driven by photorespiration.

  8. Effect of NGBFS and CBA as fine aggregate on the chloride permeability of concrete

    Directory of Open Access Journals (Sweden)

    İsa Yüksel

    2013-09-01

    Full Text Available This paper presents the results of an investigation which was about influence of non-ground Coal Bottom Ash (CBA and Non-Ground Granulated Blast-Furnace Slag (NGBFS as fine aggregate on rapid chloride permeability of concrete. Series of Rapid Chloride Permeability Test (RCPT were conducted with concrete specimens containing NGBFS and CBA in varying percentages from 10 to 50% with the step of 10% of fine aggregate by weight. Two basic series concrete specimens were prepared in laboratory. The first series (G was contained NGBFS, the second series (B was contained CBA as fine aggregate. Test results indicated that NGBFS or CBA improves the resistance to chloride ion penetration tosome extent. 30% and 10% replacement ratios were selected as optimum replacement ratios for G and B series. It was concluded that GBFS was more impressive then CBA for blocking chloride ion movements.

  9. Diversity, intent, and aggregated search

    NARCIS (Netherlands)

    de Rijke, M.

    2014-01-01

    Diversity, intent and aggregated search are three core retrieval concepts that receive significant attention. In search result diversification one typically considers the relevance of a document in light of other retrieved documents. The goal is to identify the probable "aspects" of an ambiguous

  10. Diversity, intent, and aggregated search

    NARCIS (Netherlands)

    M. de Rijke

    2014-01-01

    Diversity, intent and aggregated search are three core retrieval concepts that receive significant attention. In search result diversification one typically considers the relevance of a document in light of other retrieved documents. The goal is to identify the probable "aspects" of an ambiguous que

  11. Quantitative investigations of aggregate systems.

    Science.gov (United States)

    Rai, D K; Beaucage, G; Jonah, E O; Britton, D T; Sukumaran, S; Chopra, S; Gonfa, G Goro; Härting, M

    2012-07-28

    Nanomaterials with disordered, ramified structure are increasingly being used for applications where low cost and enhanced performance are desired. A particular example is the use in printed electronics of inorganic conducting and semiconducting nanoparticles. The electrical, as well as other physical properties depend on the arrangement and connectivity of the particles in such aggregate systems. Quantification of aggregate structure and development of structure/property relationships is difficult and progress in the application of these materials in electronics has mainly been empirical. In this paper, a scaling model is used to parameterize the structure of printed electronic layers. This model has chiefly been applied to polymers but surprisingly it shows applicability to these nanolayers. Disordered structures of silicon nanoparticles forming aggregates are investigated using small angle x-ray scattering coupled with the scaling model. It is expected that predictions using these structural parameters can be made for electrical properties. The approach may have wide use in understanding and designing nano-aggregates for electronic devices.

  12. Leaching assessment of concrete made of recycled coarse aggregate: physical and environmental characterisation of aggregates and hardened concrete.

    Science.gov (United States)

    Galvín, A P; Agrela, F; Ayuso, J; Beltrán, M G; Barbudo, A

    2014-09-01

    Each year, millions of tonnes of waste are generated worldwide, partially through the construction and demolition of buildings. Recycling the resulting waste could reduce the amount of materials that need to be manufactured. Accordingly, the present work has analysed the potential reuse of construction waste in concrete manufacturing by replacing the natural aggregate with recycled concrete coarse aggregate. However, incorporating alternative materials in concrete manufacturing may increase the pollutant potential of the product, presenting an environmental risk via ground water contamination. The present work has tested two types of concrete batches that were manufactured with different replacement percentages. The experimental procedure analyses not only the effect of the portion of recycled aggregate on the physical properties of concrete but also on the leaching behaviour as indicative of the contamination degree. Thus, parameters such as slump, density, porosity and absorption of hardened concrete, were studied. Leaching behaviour was evaluated based on the availability test performed to three aggregates (raw materials of the concrete batches) and on the diffusion test performed to all concrete. From an environmental point of view, the question of whether the cumulative amount of heavy metals that are released by diffusion reaches the availability threshold was answered. The analysis of concentration levels allowed the establishment of different groups of metals according to the observed behaviour, the analysis of the role of pH and the identification of the main release mechanisms. Finally, through a statistical analysis, physical parameters and diffusion data were interrelated. It allowed estimating the relevance of porosity, density and absorption of hardened concrete on diffusion release of the metals in study. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Sequence-dependent internalization of aggregating peptides.

    Science.gov (United States)

    Couceiro, José R; Gallardo, Rodrigo; De Smet, Frederik; De Baets, Greet; Baatsen, Pieter; Annaert, Wim; Roose, Kenny; Saelens, Xavier; Schymkowitz, Joost; Rousseau, Frederic

    2015-01-02

    Recently, a number of aggregation disease polypeptides have been shown to spread from cell to cell, thereby displaying prionoid behavior. Studying aggregate internalization, however, is often hampered by the complex kinetics of the aggregation process, resulting in the concomitant uptake of aggregates of different sizes by competing mechanisms, which makes it difficult to isolate pathway-specific responses to aggregates. We designed synthetic aggregating peptides bearing different aggregation propensities with the aim of producing modes of uptake that are sufficiently distinct to differentially analyze the cellular response to internalization. We found that small acidic aggregates (≤500 nm in diameter) were taken up by nonspecific endocytosis as part of the fluid phase and traveled through the endosomal compartment to lysosomes. By contrast, bigger basic aggregates (>1 μm) were taken up through a mechanism dependent on cytoskeletal reorganization and membrane remodeling with the morphological hallmarks of phagocytosis. Importantly, the properties of these aggregates determined not only the mechanism of internalization but also the involvement of the proteostatic machinery (the assembly of interconnected networks that control the biogenesis, folding, trafficking, and degradation of proteins) in the process; whereas the internalization of small acidic aggregates is HSF1-independent, the uptake of larger basic aggregates was HSF1-dependent, requiring Hsp70. Our results show that the biophysical properties of aggregates determine both their mechanism of internalization and proteostatic response. It remains to be seen whether these differences in cellular response contribute to the particular role of specific aggregated proteins in disease.

  14. Concrete using agro-waste as fine aggregate for sustainable built environment – A review

    Directory of Open Access Journals (Sweden)

    Jnyanendra Kumar Prusty

    2016-12-01

    Full Text Available High demand of natural resources due to rapid urbanization and the disposal problem of agricultural wastes in developed countries have created opportunities for use of agro-waste in the construction industry. Many agricultural waste materials are already used in concrete as replacement alternatives for cement, fine aggregate, coarse aggregate and reinforcing materials. This paper reviews some of the agro-waste materials, which are used as a partial replacement of fine aggregate in concrete. Different properties of fresh and hardened concrete, their durability and thermal conductivity when admixed with agro-wastes are reviewed. Agro-waste used in self-compacting concrete and mortar are also reviewed and their properties are compared. It has been seen that the agro-waste concrete containing groundnut shell, oyster shell, cork, rice husk ash and tobacco waste showed better workability than their counterparts did. Agro-waste concrete containing bagasse ash, sawdust ash and oyster shell achieved their required strength by 20% of replacement as fine aggregate, which were maximum among all agro-waste type concrete. Close relations were predicted among compressive strength, flexural strength, tensile strength, ultrasonic pulse velocity and elastic modulus of agro-waste concrete. Addition of bagasse ash as fine aggregate in mortar increased the resistance of chloride penetration whereas inclusion of cork in mortar showed better thermal resistance and improved cyclic performance. After the review, it is of considerable finding that more research is deserved on all fine aggregates replacing agro-waste materials, which can give more certainty on their utilization in concrete.

  15. Prediction of the absolute aggregation rates of amyloidogenic polypeptide chains.

    Science.gov (United States)

    DuBay, Kateri F; Pawar, Amol P; Chiti, Fabrizio; Zurdo, Jesús; Dobson, Christopher M; Vendruscolo, Michele

    2004-08-27

    Protein aggregation is associated with a variety of pathological conditions, including Alzheimer's and Creutzfeldt-Jakob diseases and type II diabetes. Such degenerative disorders result from the conversion of the normal soluble state of specific proteins into aggregated states that can ultimately form the characteristic amyloid fibrils found in diseased tissue. Under appropriate conditions it appears that many, perhaps all, proteins can be converted in vitro into amyloid fibrils. The aggregation propensities of different polypeptide chains have, however, been observed to vary substantially. Here, we describe an approach that uses the knowledge of the amino acid sequence and of the experimental conditions to reproduce, with a correlation coefficient of 0.92 and over five orders of magnitude, the in vitro aggregation rates of a wide range of unstructured peptides and proteins. These results indicate that the formation of protein aggregates can be rationalised to a considerable extent in terms of simple physico-chemical parameters that describe the properties of polypeptide chains and their environment.

  16. Properties of Non-Structural Concrete Made with Mixed Recycled Aggregates and Low Cement Content

    Directory of Open Access Journals (Sweden)

    Antonio López-Uceda

    2016-01-01

    Full Text Available In spite of not being legally accepted in most countries, mixed recycled aggregates (MRA could be a suitable raw material for concrete manufacturing. The aims of this research were as follows: (i to analyze the effect of the replacement ratio of natural coarse aggregates with MRA, the amount of ceramic particles in MRA, and the amount of cement, on the mechanical and physical properties of a non-structural concrete made with a low cement content; and (ii to verify if it is possible to achieve a low-strength concrete that replaces a greater amount of natural aggregate with MRA and that has a low cement content. Two series of concrete mixes were manufactured using 180 and 200 kg/m3 of CEM II/A-V 42.5 R type Portland cement. Each series included seven concrete mixes: one with natural aggregates; two MRA with different ceramic particle contents; and one for each coarse aggregate replacement ratio (20%, 40%, and 100%. To study their properties, compressive and splitting tensile strength, modulus of elasticity, density, porosity, water penetration, and sorptivity, tests were performed. The results confirmed that the main factors affecting the properties analyzed in this research are the amount of cement and the replacement ratio; the two MRAs used in this work presented a similar influence on the properties. A non-structural, low-strength concrete (15 MPa with an MRA replacement ratio of up to 100% for 200 kg/m3 of cement was obtained. This type of concrete could be applied in the construction of ditches, sidewalks, and other similar civil works.

  17. Ensuring Machine and Tractor Aggregates Operability

    Science.gov (United States)

    Redreev, G. V.

    2016-08-01

    the operability of the machine and tractor aggregates is ensured by processes which occur in machine units and considered as technical systems. In order to develop theoretical understanding of the processes in technical systems as the basis and purpose of the repairserving actions, the author's concept is presented which relies on on the basic concepts of "processes in technical systems", "maintenance and repair of performers", "maintenance and repair of technology" "objectives of the maintenance and repair". Analysis of the basic concepts of "processes in technical systems" made possible to distinguishing four types of relations: of order, stipulation, exactingness, and non-contradiction. It is shown that the implementation of maintenance and repair of technology should be conducted according to the assessment of the effectiveness of processes in technical systems, revealed in complex diagnosis. The perfection of the design of the machine in terms of its technical operation can be estimated according to the degree of consistency of processes in technical systems, purposes of maintenance and repair. In order to increase the efficiency of the lubrication system,the modernised design of the centrifugal oil filter with permanent control of its cleaning power is offered, which allows changing the technology of the maintenance of engine lubrication system by separating the operations of crankcase oil replacement and the rotor filter cleaning.

  18. Computational investigation of the neutron shielding and activation characteristics of borated concrete with polyethylene aggregate

    Energy Technology Data Exchange (ETDEWEB)

    Park, S.J.; Jang, J.G.; Lee, H.K., E-mail: leeh@kaist.ac.kr

    2014-09-15

    This paper presents the result of a computational study to investigate the neutron shielding and activation characteristics of concretes containing boron carbide and polyethylene. Various mixes were considered with changes in the contents of boron carbide and polyethylene aggregate. The Monte Carlo simulation code MCNP-5 was utilized to determine the transmission of neutron through concrete at different energies from 0.1 eV to 1 MeV, and ORIGEN-S code was then used to predict activation characteristics of the concretes. It was shown that the replacement of polyethylene in borated concrete greatly enhanced the shielding efficiency of the concrete, and total activity levels of the concrete were considerably decreased with this replacement. Furthermore, double-layered structures having the first layer of polyethylene aggregate-replaced concrete and the second layer of 2 wt% borated concrete are shown to improve shielding efficiency more significantly than monolithic structures.

  19. Spontaneous Coronary Artery Dissection following Topical Hormone Replacement Therapy

    OpenAIRE

    2012-01-01

    Spontaneous coronary artery dissection is a rare condition, usually presenting as an acute coronary syndrome, and is often seen in states associated with high systemic estrogen levels such as pregnancy or oral contraceptive use. While topical hormonal replacement therapy may result in increased estrogen levels similar to those documented with oral contraceptive use, there are no reported cases of spontaneous coronary dissection with topical hormonal replacement therapy. We describe a 53-year...

  20. Knee Replacement: What you can Expect

    Science.gov (United States)

    ... improves function lessen with each additional surgery. Artificial knees can wear out Another risk of knee replacement ... replacement surgery to last about two hours. After knee replacement surgery After surgery, you're wheeled to ...

  1. Chemical-mineralogical characterisation of coarse recycled concrete aggregate.

    Science.gov (United States)

    Limbachiya, M C; Marrocchino, E; Koulouris, A

    2007-01-01

    The construction industry is now putting greater emphasis than ever before on increasing recycling and promoting more sustainable waste management practices. In keeping with this approach, many sectors of the industry have actively sought to encourage the use of recycled concrete aggregate (RCA) as an alternative to primary aggregates in concrete production. The results of a laboratory experimental programme aimed at establishing chemical and mineralogical characteristics of coarse RCA and its likely influence on concrete performance are reported in this paper. Commercially produced coarse RCA and natural aggregates (16-4 mm size fraction) were tested. Results of X-ray fluorescence (XRF) analyses showed that original source of RCA had a negligible effect on the major elements and a comparable chemical composition between recycled and natural aggregates. X-ray diffraction (XRD) analyses results indicated the presence of calcite, portlandite and minor peaks of muscovite/illite in recycled aggregates, although they were directly proportioned to their original composition. The influence of 30%, 50%, and 100% coarse RCA on the chemical composition of equal design strength concrete has been established, and its suitability for use in a concrete application has been assessed. In this work, coarse RCA was used as a direct replacement for natural gravel in concrete production. Test results indicated that up to 30% coarse RCA had no effect on the main three oxides (SiO2, Al2O3 and CaO) of concrete, but thereafter there was a marginal decrease in SiO2 and increase in Al2O3 and CaO contents with increase in RCA content in the mix, reflecting the original constituent's composition.

  2. Homologous gene replacement in Physarum

    Energy Technology Data Exchange (ETDEWEB)

    Burland, T.G. [Univ. of Wisconsin, Madison, WI (United States); Pallotta, D. [Laval Univ., Quebec (Canada)

    1995-01-01

    The protist Physarum polycephalum is useful for analysis of several aspects of cellular and developmental biology. To expand the opportunities for experimental analysis of this organism, we have developed a method for gene replacement. We transformed Physarum amoebae with plasmid DNA carrying a mutant allele, ardD{Delta}1, of the ardD actin gene; ardD{Delta}1 mutates the critical carboxy-terminal region of the gene product. Because ardD is not expressed in the amoeba, replacement of ardD{sup +} with ardD{Delta}1 should not be lethal for this cell type. Transformants were obtained only when linear plasmid DNA was used. Most transformants carried one copy of ardD{Delta}1 in addition to ardD{sup +}, but in two (5%), ardD{sup +} was replaced by a single copy of ardD{Delta}1. This is the first example of homologous gene replacement in Physarum. ardD{Delta}1 was stably maintained in the genome through growth, development and meiosis. We found no effect of ardD{Delta}l on viability, growth, or development of any of the various cell types of Physarum. Thus, the carboxy-terminal region of the ardD product appears not to perform a unique essential role in growth or development. Nevertheless, this method for homologous gene replacement can be applied to analyze the function of any cloned gene. 38 refs., 6 figs., 1 tab.

  3. Optimizing model. 1. Insemination, replacement, seasonal production and cash flow.

    NARCIS (Netherlands)

    Delorenzo, M.A.; Spreen, T.H.; Bryan, G.R.; Beede, D.K.; Arendonk, van J.A.M.

    1992-01-01

    Dynamic programming to solve the Markov decision process problem of optimal insemination and replacement decisions was adapted to address large dairy herd management decision problems in the US. Expected net present values of cow states (151,200) were used to determine the optimal policy. States

  4. Optimizing model. 1. Insemination, replacement, seasonal production and cash flow.

    NARCIS (Netherlands)

    Delorenzo, M.A.; Spreen, T.H.; Bryan, G.R.; Beede, D.K.; Arendonk, van J.A.M.

    1992-01-01

    Dynamic programming to solve the Markov decision process problem of optimal insemination and replacement decisions was adapted to address large dairy herd management decision problems in the US. Expected net present values of cow states (151,200) were used to determine the optimal policy. States wer

  5. Role of streams in myxobacteria aggregate formation

    Science.gov (United States)

    Kiskowski, Maria A.; Jiang, Yi; Alber, Mark S.

    2004-10-01

    Cell contact, movement and directionality are important factors in biological development (morphogenesis), and myxobacteria are a model system for studying cell-cell interaction and cell organization preceding differentiation. When starved, thousands of myxobacteria cells align, stream and form aggregates which later develop into round, non-motile spores. Canonically, cell aggregation has been attributed to attractive chemotaxis, a long range interaction, but there is growing evidence that myxobacteria organization depends on contact-mediated cell-cell communication. We present a discrete stochastic model based on contact-mediated signaling that suggests an explanation for the initialization of early aggregates, aggregation dynamics and final aggregate distribution. Our model qualitatively reproduces the unique structures of myxobacteria aggregates and detailed stages which occur during myxobacteria aggregation: first, aggregates initialize in random positions and cells join aggregates by random walk; second, cells redistribute by moving within transient streams connecting aggregates. Streams play a critical role in final aggregate size distribution by redistributing cells among fewer, larger aggregates. The mechanism by which streams redistribute cells depends on aggregate sizes and is enhanced by noise. Our model predicts that with increased internal noise, more streams would form and streams would last longer. Simulation results suggest a series of new experiments.

  6. Structural Concrete Prepared with Coarse Recycled Concrete Aggregate: From Investigation to Design

    Directory of Open Access Journals (Sweden)

    Valeria Corinaldesi

    2011-01-01

    Full Text Available An investigation of mechanical behaviour and elastic properties of recycled aggregate concrete (RAC is presented. RACs were prepared by using a coarse aggregate fraction made of recycled concrete coming from a recycling plant in which rubble from concrete structure demolition is collected and suitably treated. Several concrete mixtures were prepared by using either the only virgin aggregates (as reference or 30% coarse recycled aggregate replacing gravel and by using two different kinds of cement. Different water-to-cement ratios were adopted ranging from 0.40 to 0.60. Concrete workability was always in the range 190–200 mm. Concrete compressive strength, elastic modulus, and drying shrinkage were evaluated. Results obtained showed that structural concrete up to C32/40 strength class can be manufactured with RAC. Moreover, results obtained from experimentation were discussed in order to obtain useful information for RAC structure design, particularly in terms of elastic modulus and drying shrinkage prediction.

  7. Residual Mechanical Properties of Concrete Made with Crushed Clay Bricks and Roof Tiles Aggregate after Exposure to High Temperatures

    Directory of Open Access Journals (Sweden)

    Ivana Miličević

    2016-04-01

    Full Text Available This paper presents the residual mechanical properties of concrete made with crushed bricks and clay roof tile aggregates after exposure to high temperatures. One referent mixture and eight mixtures with different percentages of replacement of natural aggregate by crushed bricks and roof tiles are experimentally tested. The properties of the concrete were measured before and after exposure to 200, 400, 600 and 800 °C. In order to evaluate the basic residual mechanical properties of concrete with crushed bricks and roof tiles after exposure to high temperatures, ultrasonic pulse velocity is used as a non-destructive test method and the results are compared with those of a destructive method for validation. The mixture with the highest percentage of replacement of natural aggregate by crushed brick and roof tile aggregate has the best physical, mechanical, and thermal properties for application of such concrete in precast concrete elements exposed to high temperatures.

  8. Sex hormone replacement in Turner syndrome

    DEFF Research Database (Denmark)

    Trolle, Christian; Hjerrild, Britta; Cleemann, Line Hartvig

    2012-01-01

    osteoporosis seen in Turner syndrome. But sex hormone insufficiency is also involved in the increased cardiovascular risk, state of physical fitness, insulin resistance, body composition, and may play a role in the increased incidence of autoimmunity. Severe morbidity and mortality affects females with Turner...... syndrome. Recent research emphasizes the need for proper sex hormone replacement therapy (HRT) during the entire lifespan of females with TS and new hypotheses concerning estrogen receptors, genetics and the timing of HRT offers valuable new information. In this review, we will discuss the effects...

  9. Experimental Research on Compounding Concrete with Recycled Aggregates%用再生骨料配制混凝土的试验研究

    Institute of Scientific and Technical Information of China (English)

    张秀芳; 何更新; 赵霄龙

    2011-01-01

    Through the replacement of partial or the whole natural aggregates with recycled coarse aggregate and recycled fine aggregate, the influences of replacement ratios of recycled coarse aggregate and recycled fine aggregate on concrete performance have been investigated. The results showed that with the increasing of replacement ratio of recycled aggregate, the water demand increasing linearly, and the compressive strength and the bulk density reducing. It is pointed out that the replacement ratio of grade I recycled aggregate has no limit, but the replacement ratio of grade II and grade III recycled aggregate should be controlled in 50% for C30 and C40 concrete. Moreover the recycled coarse aggregate and recycled fine aggregate should not be used together in the concrete.%通过分别采用再生粗骨料和再生细骨料取代部分或全部天然砂石骨料,研究再生粗(细)骨料取代率对混凝土性能的影响.试验结果表明,随着再生粗(细)骨料取代率的提高,混凝土用水量呈线性增加,而抗压强度呈线性下降,表观密度也随之下降.最后指出Ⅰ类再生骨料取代率可不受限制,对于C30,C40混凝土Ⅱ,Ⅲ类宜在50%以内,且不宜同时掺再生粗骨料和再生细骨料.

  10. Teaching Keynes's Principle of Effective Demand Using the Aggregate Labor Market Diagram.

    Science.gov (United States)

    Dalziel, Paul; Lavoie, Marc

    2003-01-01

    Suggests a method to teach John Keynes's principle of effective demand using a standard aggregate labor market diagram familiar to students taking advanced undergraduate macroeconomics courses. States the analysis incorporates Michal Kalecki's version to show Keynesian unemployment as a point on the aggregate labor demand curve inside the…

  11. Cobra Probes Containing Replaceable Thermocouples

    Science.gov (United States)

    Jones, John; Redding, Adam

    2007-01-01

    A modification of the basic design of cobra probes provides for relatively easy replacement of broken thermocouples. Cobra probes are standard tube-type pressure probes that may also contain thermocouples and that are routinely used in wind tunnels and aeronautical hardware. They are so named because in side views, they resemble a cobra poised to attack. Heretofore, there has been no easy way to replace a broken thermocouple in a cobra probe: instead, it has been necessary to break the probe apart and then rebuild it, typically at a cost between $2,000 and $4,000 (2004 prices). The modified design makes it possible to replace the thermocouple, in minimal time and at relatively low cost, by inserting new thermocouple wire in a tube.

  12. MBAR-enhanced lattice Monte Carlo simulation of the effect of helices on membrane protein aggregation

    Science.gov (United States)

    Xu, Yuanwei; Rodger, P. Mark

    2017-03-01

    We study the effect of helical structure on the aggregation of proteins using a simplified lattice protein model with an implicit membrane environment. A recently proposed Monte Carlo approach, which exploits the proven statistical optimality of the MBAR estimator in order to improve simulation efficiency, was used. The results show that with both two and four proteins present, the tendency to aggregate is strongly expedited by the presence of amphipathic helix (APH), whereas a transmembrane helix (TMH) slightly disfavours aggregation. When four protein molecules are present, partially aggregated states (dimers and trimers) were more common when the APH was present, compared with the cases where no helices or only the TMH is present.

  13. SYSTEM AGGREGATION METHOD FOR FAILURE PRONE PRODUCTION LINES WITH UNRELIABLE LIMITED BUFFERS

    Institute of Scientific and Technical Information of China (English)

    LIU Jun; RUI Zhiyuan; ZHAO Juntian; WEI Yaobing

    2008-01-01

    Different from traditional aggregation method, the unreliable buffers are originally considered and a more general aggregation method is offered, in which not only the unreliable buffers are considered, but also the probabilities of system states are obtained by a discrete model rather than the continuous flow model of unreliable manufacturing systems. The solution technique is offered to get the system sate probabilities. The method advances the traditional system aggregation techniques. Numerical results specify the extended aggregation method and also show that the unreliable limited buffers have a strong impact on the efficiency of the production lines.

  14. New Online Ecology of Adversarial Aggregates: ISIS and beyond

    CERN Document Server

    Johnson, N F; Vorobyeva, Y; Gabriel, A; Qi, H; Velasquez, N; Manrique, P; Johnson, D; Restrepo, E; Song, C; Wuchty, S

    2016-01-01

    Support for an extremist entity such as Islamic State (ISIS) somehow manages to survive globally online despite significant external pressure, and may ultimately inspire acts by individuals who have no prior history of extremism, formal cell membership or direct links to leadership. We uncover an ultrafast ecology driving this online support and provide a mathematical theory that describes it. The ecology features self-organized aggregates that proliferate preceding the onset of recent real-world campaigns, and adopt novel adaptive mechanisms to enhance their survival. One of the actionable predictions is that the development of large, potentially potent pro-ISIS aggregates can be thwarted by targeting smaller ones.

  15. How Would You Like to Aggregate Your Temporal Data?

    DEFF Research Database (Denmark)

    Böhlen, M. H.; Gamper, J.; Jensen, Christian Søndergaard

    2006-01-01

    Real-world data management applications generally manage temporal data, i.e., they manage multiple states of time-varying data. Many contributions have been made by the research community for how to better model, store, and query temporal data. In particular, several dozen temporal data models...... concepts, and it discusses the abilities of five approaches to the design of temporal query languages with respect to temporal aggregation. Rather than providing focused, polished results, the paper?s aim is to explore the inherent support for temporal aggregation in an informal manner that may serve...

  16. AGGREGATE RATING MODEL IN THE TOURISM INDUSTRY

    Directory of Open Access Journals (Sweden)

    Maris Angela

    2014-07-01

    Full Text Available In the paper the authors present a model aggregate rating based on credit-scoring models, banking models and their rating model. Multi-criteria approach and an aggregate model better capture business risk of the company.

  17. Protein aggregates in Huntington’s disease

    Science.gov (United States)

    Arrasate, Montserrat; Finkbeiner, Steven

    2014-01-01

    Huntington’s disease (HD) is an incurable neurodegenerative disease characterized by abnormal motor movements, personality changes, and early death. HD is caused by a mutation in the IT-15 gene that expands abnormally the number of CAG nucleotide repeats. As a result, the translated protein huntingtin contains disease-causing expansions of glutamines (polyQ) that make it prone to misfold and aggregate. While the gene and mutations that cause HD are known, the mechanisms underlying HD pathogenesis are not. Here we will review the state of knowledge of HD, focusing especially on a hallmark pathological feature—intracellular aggregates of mutant Htt called inclusion bodies (IBs). We will describe the role of IBs in the disease. We speculate that IB formation could be just one component of a broader coping response triggered by misfolded Htt whose efficacy may depend on the extent to which it clears toxic forms of mutant Htt. We will describe how IB formation might be regulated and which factors could determine different coping responses in different subsets of neurons. A differential regulation of IB formation as a function of the cellular context could, eventually, explain part of the neuronal vulnerability observed in HD. PMID:22200539

  18. Renal replacement therapy in ICU

    Directory of Open Access Journals (Sweden)

    C Deepa

    2012-01-01

    Full Text Available Diagnosing and managing critically ill patients with renal dysfunction is a part of the daily routine of an intensivist. Acute kidney insufficiency substantially contributes to the morbidity and mortality of critically ill patients. Renal replacement therapy (RRT not only does play a significant role in the treatment of patients with renal failure, acute as well as chronic, but also has spread its domains to the treatment of many other disease conditions such as myaesthenia gravis, septic shock and acute on chronic liver failure. This article briefly outlines the role of renal replacement therapy in ICU.

  19. Prioritization methodology for chemical replacement

    Science.gov (United States)

    Goldberg, Ben; Cruit, Wendy; Schutzenhofer, Scott

    1995-01-01

    This methodology serves to define a system for effective prioritization of efforts required to develop replacement technologies mandated by imposed and forecast legislation. The methodology used is a semi quantitative approach derived from quality function deployment techniques (QFD Matrix). QFD is a conceptual map that provides a method of transforming customer wants and needs into quantitative engineering terms. This methodology aims to weight the full environmental, cost, safety, reliability, and programmatic implications of replacement technology development to allow appropriate identification of viable candidates and programmatic alternatives.

  20. Wafer Replacement Cluster Tool (Presentation);

    Energy Technology Data Exchange (ETDEWEB)

    Branz, H. M.

    2008-04-01

    This presentation on wafer replacement cluster tool discusses: (1) Platform for advanced R and D toward SAI 2015 cost goal--crystal silicon PV at area costs closer to amorphous Si PV, it's 15% efficiency, inexpensive substrate, and moderate temperature processing (<800 C); (2) Why silicon?--industrial and knowledge base, abundant and environmentally benign, market acceptance, and good efficiency; and (3) Why replace wafers?--expensive, high embedded energy content, and uses 50-100 times more silicon than needed.

  1. The utility of trans-catheter aortic valve replacement after commercialization: does the European experience provide a glimpse into the future use of this technology in the United States?

    Science.gov (United States)

    Linke, Axel; Walther, Thomas; Schuler, Gerhard

    2010-03-01

    Treatment of aortic stenosis remains challenging in older individuals, as their perioperative mortality for open heart surgery is increased due to comorbidities. Transcatheter aortic valve implantation using the CoreValve ReValving System (Medtronic, Minneapolis, USA) and the Edwards SAPIEN transcatheter heart valve (THV; Edwards Lifescience, Irvine, California, USA) represents an alternative to conventional valve replacement in elderly patients that have a high risk for conventional surgery. This article summarizes the evidence-base from recent clinical trials. The early results of these landmark studies suggest that transcatheter aortic valve implantation with either one of the prosthesis is feasible, safe, improves hemodynamics and, therefore, might be an alternative to conventional aortic valve replacement in very high-risk patients. However, all of the available transcatheter heart valves have certain disadvantages, limiting their use in daily clinical practice. The process of decision making, which valve to use and which access route to choose is illustrated in this article through clinical case scenarios. Additionally, the lessons learned thus far from the European perspective and the potential impact on the future use in the US are discussed. Despite of the progress in this field, we are still lacking an optimal transcatheter heart valve. Once it is available, we can take the plunge to compare transcatheter valve implantation with convention surgery in severe aortic stenosis!

  2. Protein aggregation in salt solutions

    Science.gov (United States)

    Kastelic, Miha; Kalyuzhnyi, Yurij V.; Hribar-Lee, Barbara; Dill, Ken A.; Vlachy, Vojko

    2015-01-01

    Protein aggregation is broadly important in diseases and in formulations of biological drugs. Here, we develop a theoretical model for reversible protein–protein aggregation in salt solutions. We treat proteins as hard spheres having square-well-energy binding sites, using Wertheim’s thermodynamic perturbation theory. The necessary condition required for such modeling to be realistic is that proteins in solution during the experiment remain in their compact form. Within this limitation our model gives accurate liquid–liquid coexistence curves for lysozyme and γ IIIa-crystallin solutions in respective buffers. It provides good fits to the cloud-point curves of lysozyme in buffer–salt mixtures as a function of the type and concentration of salt. It than predicts full coexistence curves, osmotic compressibilities, and second virial coefficients under such conditions. This treatment may also be relevant to protein crystallization. PMID:25964322

  3. Acetone:isomedzation and aggregation

    Institute of Scientific and Technical Information of China (English)

    HU Zhan; JIN Ming-xing; XU Xue-song; CHENG Xi-hui; DING Da-jun

    2006-01-01

    The advanced experimental and theoretical techniques enable us to obtain information on the rearrangement of atoms or molecules in a reaction nowadays.As an example,we report on our research work on acetone isomerization and aggregation to give an insight into the reaction pathways,the products and their structures,and the growth regularity of aggregation.The evidences on the structural change of acetone and the stability of acetone clusters are found by a laser ionization mass spectrometer and the results are interpreted from theoretical analysis based on the DFT/B3LYP method.Various isomerization channels of acetone have been established and the optimal structures of the neutral clusters (CH3COCH3)n and the protonated acetone clusters (CH3COCHa)n H+ for n=1-7 have been determined.

  4. Geometrical Aspects During Formation of Compact Aggregates of Red Blood Cells

    Directory of Open Access Journals (Sweden)

    Cardoso A.V.

    2002-01-01

    Full Text Available In the past forty years considerable progress has been achieved on the knowledge of human blood as a non-Newtonian shear-thinning suspension, whose initial state, that is at rest (stasis or at very low shear rates, has a gel-like internal structure which is destroyed as shear stress increases. The main goal of this communication is to describe the role of geometrical aspects during RBC (red blood cell aggregate formation, growth and compaction on naturally aggregate (porcine blood and non-aggregate (bovine blood samples. We consider how these aspects coupled with tension equilibrium are decisive to transform red cell linear roleaux to three-dimensional aggregates or clusters. Geometrical aspects are also crucial on the compaction of red blood cell aggregates. These densely packed aggregates could precipitate out of blood- either as dangerous deposits on arterial walls, or as clots which travel in suspension until they block some crucial capillary.

  5. Identifying and Removing Barriers to Expanding Municipal Aggregation in the Commonwealth

    Science.gov (United States)

    Morrill, Micaelah Burke

    This thesis examines the process to become a municipal aggregator in Massachusetts and offers recommendations on improving the process. In 1997, the Commonwealth of Massachusetts restructured its electricity market and allowed municipalities and those working jointly to purchase electricity for their constituents. Municipal aggregators provide additional competition in the electricity market, public control of electricity purchases, and are in a unique position to provide consumers additional options to promote specific types of electricity generation. Since 1997, only six municipal aggregators have been approved in Massachusetts. In order to identify reasons why, this thesis includes interviews with people involved in the municipal aggregation process in Massachusetts and comparisons with other states that also have municipal aggregation programs. It also includes a historical look at electricity markets both on the federal level and in Massachusetts, and provides information on regulatory requirements municipal aggregators must meet.

  6. The effect of fly ash to self-compactability of pumice aggregate lightweight concrete

    Indian Academy of Sciences (India)

    Murat Kurt; Abdulkadir Cüneyt Aydin; Muhammed Said Gül; Rüstem Gül; Türkay Kotan

    2015-06-01

    This paper presents the results of an experimental study on the effects of fly ash, different water/(cement + mineral additive) ratios and pumice aggregates to some physical and mechanical properties of self-compacting lightweight aggregate concrete. In this study, pumice had been used as lightweight aggregates. Several properties of self-compacting pumice aggregate lightweight concretes like the unit weight, flow diameter, T50 time, flow diameter after an hour, V-funnel time, and L-box tests, 7, 28, 90 and 180-day compressive strength, 28-day splitting tensile strength, dry unit weight, water absorption, thermal conductivity and ultrasonic pulse velocity tests were investigated. For this purpose, 18 series of concrete samples were prepared in two groups. Pumice aggregate was used as a replacement of natural aggregate, at the levels of 0, 20, 40, 60, 80, and 100% by volume. Furthermore, a second series of 100% pumice aggregate was used for the production of self-compacting lightweight aggregate concrete with constant w/(c+m) ratios as 0.35, 0.40, and 0.45 by weight. The flow diameters, T50 times, paste volumes, 28-day compressive strengths, dry unit weights and thermal conductivities of self-compacting lightweight aggregate concrete were obtained in the range of 600–800 mm, 2–8 s, 471–572 lt/m3, 9.2–53.26 MPa, 839–2156 kg/m3 and 0.321–1.508 W/mk, respectively, which satisfies not only the strength requirement of semi-structural lightweight concrete but also the flowing ability requirements and thermal conductivity requirements of self-compacting lightweight aggregate concrete.

  7. Data relationship degree-based clustering data aggregation for VANET

    Science.gov (United States)

    Kumar, Rakesh; Dave, Mayank

    2016-03-01

    Data aggregation is one of the major needs of vehicular ad hoc networks (VANETs) due to the constraints of resources. Data aggregation in VANET can reduce the data redundancy in the process of data gathering and thus conserving the bandwidth. In realistic applications, it is always important to construct an effective route strategy that optimises not only communication cost but also the aggregation cost. Data aggregation at the cluster head by individual vehicle causes flooding of the data, which results in maximum latency and bandwidth consumption. Another approach of data aggregation in VANET is sending local representative data based on spatial correlation of sampled data. In this article, we emphasise on the problem that recent spatial correlation data models of vehicles in VANET are not appropriate for measuring the correlation in a complex and composite environment. Moreover, the data represented by these models is generally inaccurate when compared to the real data. To minimise this problem, we propose a group-based data aggregation method that uses data relationship degree (DRD). In the proposed approach, DRD is a spatial relationship measurement parameter that measures the correlation between a vehicle's data and its neighbouring vehicles' data. The DRD clustering method where grouping of vehicle's data is done based on the available data and its correlation is presented in detail. Results prove that the representative data using proposed approach have a low distortion and provides an improvement in packet delivery ratio and throughput (up to of 10.84% and 24.82% respectively) as compared to the other state-of-the-art solutions like Cluster-Based Accurate Syntactic Compression of Aggregated Data in VANETs.

  8. Intuitionistic fuzzy aggregation and clustering

    CERN Document Server

    Xu, Zeshui

    2012-01-01

    This book offers a systematic introduction to the clustering algorithms for intuitionistic fuzzy values, the latest research results in intuitionistic fuzzy aggregation techniques, the extended results in interval-valued intuitionistic fuzzy environments, and their applications in multi-attribute decision making, such as supply chain management, military system performance evaluation, project management, venture capital, information system selection, building materials classification, and operational plan assessment, etc.

  9. Rational design of mutations that change the aggregation rate of a protein while maintaining its native structure and stability

    Science.gov (United States)

    Camilloni, Carlo; Sala, Benedetta Maria; Sormanni, Pietro; Porcari, Riccardo; Corazza, Alessandra; De Rosa, Matteo; Zanini, Stefano; Barbiroli, Alberto; Esposito, Gennaro; Bolognesi, Martino; Bellotti, Vittorio; Vendruscolo, Michele; Ricagno, Stefano

    2016-05-01

    A wide range of human diseases is associated with mutations that, destabilizing proteins native state, promote their aggregation. However, the mechanisms leading from folded to aggregated states are still incompletely understood. To investigate these mechanisms, we used a combination of NMR spectroscopy and molecular dynamics simulations to compare the native state dynamics of Beta-2 microglobulin (β2m), whose aggregation is associated with dialysis-related amyloidosis, and its aggregation-resistant mutant W60G. Our results indicate that W60G low aggregation propensity can be explained, beyond its higher stability, by an increased average protection of the aggregation-prone residues at its surface. To validate these findings, we designed β2m variants that alter the aggregation-prone exposed surface of wild-type and W60G β2m modifying their aggregation propensity. These results allowed us to pinpoint the role of dynamics in β2m aggregation and to provide a new strategy to tune protein aggregation by modulating the exposure of aggregation-prone residues.

  10. Familial aggregation of cluster headache

    Directory of Open Access Journals (Sweden)

    Simao Cruz

    2013-11-01

    Full Text Available Several studies suggest a strong familial aggregation for cluster headache (CH, but so far none of them have included subjects with probable cluster headache (PCH in accordance with the International Classification of Headache Disorders. Objective To identify cases of probable cluster headache and to assess the familial aggregation of cluster headache by including these subjects. Method Thirty-six patients attending a headache consultation and diagnosed with trigeminal autonomic headaches were subjected to a questionnaire-based interview. A telephone interview was also applied to all the relatives who were pointed out as possibly affected as well as to some of the remaining relatives. Results Twenty-four probands fulfilled the criteria for CH or PCH; they had 142 first-degree relatives, of whom five were found to have CH or PCH, including one case of CH sine headache. The risk for first-degree relatives was observed to be increased by 35- to 46-fold. Conclusion Our results suggest a familial aggregation of cluster headache in the Portuguese population.

  11. Network Provisioning Using Multimedia Aggregates

    Directory of Open Access Journals (Sweden)

    Joan Vila-Carbó

    2008-01-01

    Full Text Available Multimedia traffic makes network provisioning a key issue. Optimal provisioning of network resources is crucial for reducing the service cost of multimedia transmission. Multimedia traffic requires not only provisioning bandwidth and buffer resources in the network but also guaranteeing a given maximum end-to-end delay. In this paper we present methods and tools for the optimal dimensioning of networks based on multimedia aggregates. The proposed method minimises the network resources reservations of traffic aggregates providing a bounded delay. The paper also introduces several methods to generate multimedia traffic aggregation using real video traces. The method is evaluated using a network topology based on the European GÉANT network. The results of these simulations allow us to discover the relationship between a required delay and the necessary bandwidth reservation (or the achievable utilisation limit. An interesting conclusion of these scenarios is that, following several recommendations, the network utilisation can reach values of around 80% or higher.

  12. Aggregation patterns from nonlocal interactions: Discrete stochastic and continuum modeling

    KAUST Repository

    Hackett-Jones, Emily J.

    2012-04-17

    Conservation equations governed by a nonlocal interaction potential generate aggregates from an initial uniform distribution of particles. We address the evolution and formation of these aggregating steady states when the interaction potential has both attractive and repulsive singularities. Currently, no existence theory for such potentials is available. We develop and compare two complementary solution methods, a continuous pseudoinverse method and a discrete stochastic lattice approach, and formally show a connection between the two. Interesting aggregation patterns involving multiple peaks for a simple doubly singular attractive-repulsive potential are determined. For a swarming Morse potential, characteristic slow-fast dynamics in the scaled inverse energy is observed in the evolution to steady state in both the continuous and discrete approaches. The discrete approach is found to be remarkably robust to modifications in movement rules, related to the potential function. The comparable evolution dynamics and steady states of the discrete model with the continuum model suggest that the discrete stochastic approach is a promising way of probing aggregation patterns arising from two- and three-dimensional nonlocal interaction conservation equations. © 2012 American Physical Society.

  13. Rapid aggregation of biofuel-producing algae by the bacterium Bacillus sp. strain RP1137.

    Science.gov (United States)

    Powell, Ryan J; Hill, Russell T

    2013-10-01

    Algal biofuels represent one of the most promising means of sustainably replacing liquid fuels. However, significant challenges remain before alga-based fuels become competitive with fossil fuels. One of the largest challenges is the ability to harvest the algae in an economical and low-energy manner. In this article, we describe the isolation of a bacterial strain, Bacillus sp. strain RP1137, which can rapidly aggregate several algae that are candidates for biofuel production, including a Nannochloropsis sp. This bacterium aggregates algae in a pH-dependent and reversible manner and retains its aggregation ability after paraformaldehyde fixation, opening the possibility for reuse of the cells. The optimal ratio of bacteria to algae is described, as is the robustness of aggregation at different salinities and temperatures. Aggregation is dependent on the presence of calcium or magnesium ions. The efficiency of aggregation of Nannochloropsis oceanica IMET1 is between 70 and 95% and is comparable to that obtained by other means of harvest; however, the rate of harvest is fast, with aggregates forming in 30 s.

  14. Green Concrete from Sustainable Recycled Coarse Aggregates: Mechanical and Durability Properties

    Directory of Open Access Journals (Sweden)

    Neeraj Jain

    2015-01-01

    Full Text Available Present investigations deal with the development of green concrete (M 30 grade using recycled coarse aggregates for sustainable development. Characterization of recycled coarse aggregates showed that physical and mechanical properties are of inferior quality and improvement in properties was observed after washing due to removal of old weak mortar adhered on its surface. The influence of natural coarse aggregates replacement (50 and 100% with recycled coarse aggregate on various mechanical and durability properties of hardened concrete were discussed and compared with controls at different w/c ratio. Improvements in all the engineering properties of hardened concrete were observed using washed recycled coarse aggregates. The compressive strength of 28-day hardened concrete containing 100% washed recycled aggregate was slightly lower (7% than concrete prepared with natural aggregates. Water absorption, carbonation, and rapid chloride penetration test were conducted to assess the durability of the concrete. Concrete was found moderately permeable for chloride ions penetration and no carbonation was observed in all the concrete mixes studied.

  15. Study on Characteristics of Lightweight Aggregate Concrete Made From Foam and Ordinary Portland Cement

    Directory of Open Access Journals (Sweden)

    Ibrahim N.M.

    2016-01-01

    Full Text Available The production and characteristic of lightweight bubble aggregates (LBA are presented in this paper. The LBA are produced by mixing between the foam and ordinary Portland cement according to the composition which has been set. Then, the characteristics of LBA such as density, water absorption, specific gravity, compressive strength, aggregate impact value and microscopic analysis of the LBA are analyzed. Those characteristics are identified in order to ensure that the LBA are successfully categorized into lightweight aggregate. The loose bulk density is obtained at 812.5 kg/m3 which can be categorized under lightweight aggregate group. For water absorption the value obtained is 9.7 % which is slightly higher compared to normal aggregate. Meanwhile the average specific gravity obtained for the samples of LBAis 1.75. Compressive strength for the aggregates was 17.76 MPa. The highest compressive strength for LBA foamed concrete was obtained at 25% replacement with 7.83MPa. Thus, the LBA have a significant features and characteristics that can be used as coarse aggregates in concrete.

  16. Feasibility Study of Applying Recycled Aggregate from Building Debris in Concrete

    Institute of Scientific and Technical Information of China (English)

    PENG Yuzhu

    2011-01-01

    Coarse and fine aggregate constitutes an average of approximately 55% to 80% of the total volume of concrete materials.Concrete remains the most commonly-used building material worldwide.As a result,the massive use of aggregate will have a direct impact on the earth's natural resources if an appropriate replacement material is not found,violating the spirit of sustainable development.This study makes a preliminary examination of using coarse and fine aggregate produced from discarded construction materials in concrete.Results indicate that the compressive strength of densified mixture concrete at 28 days can reach 56.88MPa( recycled materials used as coarse aggregate,and natural sand used as fine aggregate)and 53.33 MPa (recycled materials used as both coarse and fine aggregate).While this type of material is not yet fully understood,further research into this area should enable feasible applications in concrete.However,unsuitable mixtures have serious impact on the durability and overall economy of concrete.Pending further research on suitable mixture designs,a complete application of recycled aggregate in concrete can be expected.

  17. Sedimentation of particles and aggregates in colloids considering both streaming and seepage

    Science.gov (United States)

    Song, Dongxing; Jin, Hui; Jin, Jingyu; Jing, Dengwei

    2016-10-01

    Sedimentation of colloids is a common phenomenon in various industrial processes. Aggregation of nanoparticles is expected to occur during the processes. However, previous studies often ignore the important features of aggregates, e.g. porosity and possible seepage, leading to a mathematical description of the sedimentation processes of low reliability. In this study, we successfully elaborated the partial differential equation of the dynamic concentration distribution of regimented colloids based on the Stokes approximation and diffusion along the negative gradient of concentration. The permeability of aggregates was obtained by the finite volume method and the ratios of the velocities of flowing around (u f) to seepage through (u s) aggregates over various primary particle sizes and aggregation structures were obtained based on the Darcy equations. After validation of the model, the effects of size and density of the particles and aggregates on the concentration profiles were investigated. Our results indicate that both an increase in size and density of particles and aggregates can accelerate the sedimentation process, and lead to more ‘thorough’ sedimentation. We mathematically explain why suspensions with high particle concentration are more unstable. What is more, replacing gravity with other volume forces, e.g. centrifugal force and magnetic forces, our model is expected to be applicable to centrifugation or magnetic sedimentation processes.

  18. Investigation on the aggregation properties of cationic [60]fullerene derivative

    Institute of Scientific and Technical Information of China (English)

    WANG Guanwu; ZHAO Guoxia; YAN Lifeng

    2004-01-01

    The UV-Vis spectra, HRTEM and AFM images of cationic fullerene derivative 1 with ammonium head group directly connected to C60 skeleton in tetrahydrofuran (THF)-water (H2O) binary mixtures and in pure H2O were investigated. It was found that the UV-Vis spectra of ammonium 1 in the THF-H2O mixtures with THF% ≥ 20% were nearly overlapped, while those with THF% < 20% showed broadened and red-shifted peaks, indicating the formation of aggregates. Corresponding to the UV-Vis spectral changes,the solvatochromism of ammonium 1 in THF-H2O mixtures was observed. Ammonium 1 in binary THF-H2O mixtures existing as the monomer state could aggregate upon prolonged standing. Higher temperature and lower concentration speeded up the aggregation process.

  19. Impact of Public Aggregate Wind Forecasts on Electricity Market Outcomes

    DEFF Research Database (Denmark)

    Exizidis, Lazaros; Kazempour, Jalal; Pinson, Pierre

    2017-01-01

    by offering better knowledge of the market operation, leading subsequently to a more competitive energy market. Driven by the above regulation, we consider an equilibrium study to address how public information of aggregate wind power forecasts can potentially affect market results, social welfare as well......Following a call to foster a transparent and more competitive market, member states of the European transmission system operator are required to publish, among other information, aggregate wind power forecasts. The publication of the latter information is expected to benefit market participants......-theoretic approach (diagonalization) is incorporated in order to investigate the existence of an equilibrium for various values of aggregate forecast. As anticipated, variations in public forecasts will affect market results and, more precisely, under-forecasts can mislead power producers to make decisions...

  20. Internet Aggregators Constructing the Political Right Wing in Japan

    Directory of Open Access Journals (Sweden)

    Muneo Kaigo

    2013-11-01

    Full Text Available The Matome Saito are edited popular topic threads of the Ni-Channel anonymous bulletin board. The information on the Matome Saito is efficiently and concisely edited for those who do not usually access the vast Ni-Channel forum. This paper overviews the state and mechanism of the Ni-Channel forum of Japan, the edited blogs of Ni-Channel called Matome Saito, and aggregation of Matome Saito in relation to online aggregation and politics, with a focus on Japan and the December 2012 election.  This paper examines the tone argument of the Matome Saito aggregation by conducting a content analysis of 148 politically related threads from November 16, 2012 to December 20, 2012 spanning the time period following the dissolving of the Japanese government by Prime Minister Noda to five days after the election.

  1. Double emulsions as fat replacers

    NARCIS (Netherlands)

    Oppermann, Anika

    2017-01-01

    The use of double (w1/o/w2) emulsions, in which part of the oil is replaced by small water droplets, is a promising strategy to reduce oil content in food products. For successful applications, (1) significant levels of fat reduction (i.e. significant amounts of water inside the oil droplets) have

  2. Electrocatalysts Prepared by Galvanic Replacement

    Directory of Open Access Journals (Sweden)

    Athanasios Papaderakis

    2017-03-01

    Full Text Available Galvanic replacement is the spontaneous replacement of surface layers of a metal, M, by a more noble metal, Mnoble, when the former is treated with a solution containing the latter in ionic form, according to the general replacement reaction: nM + mMnoblen+ → nMm+ + mMnoble. The reaction is driven by the difference in the equilibrium potential of the two metal/metal ion redox couples and, to avoid parasitic cathodic processes such as oxygen reduction and (in some cases hydrogen evolution too, both oxygen levels and the pH must be optimized. The resulting bimetallic material can in principle have a Mnoble-rich shell and M-rich core (denoted as Mnoble(M leading to a possible decrease in noble metal loading and the modification of its properties by the underlying metal M. This paper reviews a number of bimetallic or ternary electrocatalytic materials prepared by galvanic replacement for fuel cell, electrolysis and electrosynthesis reactions. These include oxygen reduction, methanol, formic acid and ethanol oxidation, hydrogen evolution and oxidation, oxygen evolution, borohydride oxidation, and halide reduction. Methods for depositing the precursor metal M on the support material (electrodeposition, electroless deposition, photodeposition as well as the various options for the support are also reviewed.

  3. Bonding over Dentin Replacement Materials.

    Science.gov (United States)

    Meraji, Naghmeh; Camilleri, Josette

    2017-08-01

    Dentin replacement materials are necessary in large cavities to protect the pulp and reduce the bulk of filling material. These materials are layered with a composite resin restorative material. Microleakage caused by poor bonding of composite resin to underlying dentin replacement material will result in pulp damage. The aim of this study was to characterize the interface between dentin replacement materials and composite resin and to measure the shear bond strength after dynamic aging. Biodentine (Septodont, Saint Maur-des-Fosses, France), Theracal LC (Bisco, Schaumburg, IL), and Fuji IX (GC, Tokyo, Japan) were used as dentin replacement materials. They were then overlaid with a total-etch and bonding agent or a self-etch primer and composite resin or a glass ionomer cement. All combinations were thermocycled for 3000 cycles. The interface was characterized using scanning electron microscopy and elemental mapping. Furthermore, the shear bond strength was assessed. The Biodentine surface was modified by etching. The Theracal LC and Fuji IX microstructure was unchanged upon the application of acid etch. The Biodentine and glass ionomer interface showed an evident wide open space, and glass particles from the glass ionomer adhered to the Biodentine surface. Elemental migration was shown with aluminum, barium, fluorine, and ytterbium present in Biodentine from the overlying composite resin. Calcium was more stable. The bond strength between Theracal LC and composite using a total-etch technique followed by self-etch primer achieved the best bond strength values. Biodentine exhibited the weakest bond with complete failure of bonding shown after demolding and thermocycling. Dynamic aging is necessary to have clinically valid data. Bonding composite resin to water-based dentin replacement materials is still challenging, and further alternatives for restoration of teeth using such materials need to be developed. Copyright © 2017 American Association of Endodontists

  4. Properties of concrete with tire derived aggregate and crumb rubber as a lighthweight substitute for mineral aggregates in the concrete mix

    Science.gov (United States)

    Siringi, Gideon Momanyi

    Scrap tires continue to be a nuisance to the environment and this research proposes one way of recycling them as a lightweight aggregate which can substitute for mineral aggregates in concrete. Aggregates derived from scrap tires are often referred to as Tire Derived Aggregate (TDA). First, the focus is how much mineral aggregate can be replaced by these waste tires and how the properties of concrete are affected with the introduction of rubber. This is being mindful of the fact that for a new material to be acceptable as an engineering material, its properties and behavior has to be well understood, the materials must perform properly and be acceptable to the regulating agencies. The role played by the quantity of TDA and Crumb Rubber replacing coarse aggregate and fine aggregate respectively as well as different treatment and additives in concrete on its properties are examined. Conventional concrete (without TDA) and concrete containing TDA are compared by examining their compressive strength based on ASTM C39, workability based on ASTM C143, Splitting Tensile Strength based on ASTM C496, Modulus of Rupture (flexural strength) based on ASTM C78 and Bond strength of concrete developed with reinforcing steel based on ASTM C234.Through stress-strain plots, the rubberized concrete is compared in terms of change in ductility, toughness and Elastic Modulus. Results indicate that while replacement of mineral aggregates with TDA results in reduction in compressive strength, this may be mitigated by addition of silica fume or using a smaller size of TDA to obtain the desired strength. The greatest benefit of using TDA is in the development of a higher ductile product with lower density while utilizing recycled TDA. From the results, it is observed that 7-10% of weight of mineral aggregates can be replaced by an equal volume of TDA to produce concrete with compressive strength of up to 4000 psi (27.5 MPa). Rubberized concrete would have higher ductility and toughness with

  5. Influence of limestone waste as partial replacement material for sand and marble powder in concrete properties

    Directory of Open Access Journals (Sweden)

    Omar M. Omar

    2012-12-01

    Full Text Available Green concrete are generally composed of recycling materials as hundred or partial percent substitutes for aggregate, cement, and admixture in concrete. Limestone waste is obtained as a by-product during the production of aggregates through the crushing process of rocks in rubble crusher units. Using quarry waste as a substitute of sand in construction materials would resolve the environmental problems caused by the large-scale depletion of the natural sources of river and mining sands. This paper reports the experimental study undertaken to investigate the influence of partial replacement of sand with limestone waste (LSW, with marble powder (M.P as an additive on the concrete properties. The replacement proportion of sand with limestone waste, 25%, 50%, and 75% were practiced in the concrete mixes except in the concrete mix. Besides, proportions of 5%, 10% and 15% marble powder were practiced in the concrete mixes. The effects of limestone waste as fine aggregate on several fresh and hardened properties of the concretes were investigated. The investigation included testing of compressive strength, indirect tensile strength, flexural strength, modulus of elasticity, and permeability. It was found that limestone waste as fine aggregate enhanced the slump test of the fresh concretes. But the unit weight concretes were not affected. However, the good performance was observed when limestone waste as fine aggregate was used in presence of marble powder.

  6. [Lysophosphatidic acid and human erythrocyte aggregation].

    Science.gov (United States)

    Sheremet'ev, Iu A; Popovicheva, A N; Levin, G Ia

    2014-01-01

    The effects of lysophosphatidic acid on the morphology and aggregation of human erythrocytes has been studied. Morphology of erythrocytes and their aggregates were studied by light microscopy. It has been shown that lysophosphatidic acid changes the shape of red blood cells: diskocyte become echinocytes. Aggregation of red blood cells (rouleaux) was significantly reduced in autoplasma. At the same time there is a strong aggregation of echinocytes. This was accompanied by the formation of microvesicles. Adding normal plasma to echinocytes restores shape and aggregation of red blood cells consisting of "rouleaux". A possible mechanism of action of lysophosphatidic acid on erythrocytes is discussed.

  7. [AGGREGATION OF METABOLICALLY DEPLETED HUMAN ERYTHROCYTES].

    Science.gov (United States)

    Sheremet'ev, Yu A; Popovicheva, A N; Rogozin, M M; Levin, G Ya

    2016-01-01

    An aggregation of erythrocytes in autologous plasma after blood storage for 14 days at 4 °C was studied using photometry and light microscopy. The decrease of ATP content, the formation of echinocytes and spheroechinocytes, the decrease of rouleaux form of erythrocyte aggregation were observed during the storage. On the other hand the aggregates of echinocytes were formed in the stored blood. The addition of plasma from the fresh blood didn't restore the normal discocytic shape and aggregation of erythrocytes in the stored blood. The possible mechanisms of erythrocytes and echinocytes aggregation are discussed.

  8. An exact approach for aggregated formulations

    DEFF Research Database (Denmark)

    Gamst, Mette; Spoorendonk, Simon

    cause an infeasible solution. In this paper, we consider (mixed) integer program formulations and propose a method for ensuring an optimal solution to the original (disaggregated) problem using an aggregated formulation. The method is based on Benders’ decomposition on a combination of the disaggregated...... mathematical formulation and the aggregated formulation. The method allows usage of relaxed aggregated formulations and enables branching on both aggregated and disaggregated variables. Also, the method guarantees an LP bound at least as good as those for the disaggregated and aggregated formulations...

  9. An Exploratory Compressive Strength Of Concrete Containing Modified Artificial Polyethylene Aggregate (MAPEA)

    Science.gov (United States)

    Hadipramana, J.; Mokhatar, S. N.; Samad, A. A. A.; Hakim, N. F. A.

    2016-11-01

    Concrete is widely used in the world as building and construction material. However, the constituent materials used in concrete are high cost when associated with the global economic recession. This exploratory aspires to have an alternative source of replacing natural aggregate with plastic wastes. An investigation of the Modified Artificial Polyethylene Aggregate (MAPEA) as natural aggregate replacement in concrete through an experimental work was conducted in this study. The MAPEA was created to improve the bonding ability of Artificial Polyethylene Aggregate (APEA) with the cement paste. The concrete was mixed with 3%, 6%, 9%, and 12% of APEA and MAPEA for 14 and 28 curing days, respectively. Furthermore, the compressive strength test was conducted to find out the optimum composition of MAPEA in concrete and compared to the APEA concrete. Besides, this study observed the influence and behaviour of MAPEA in concrete. Therefore, the Scanning Electron Microscopy was applied to observe the microstructure of MAPEA and APEA concrete. The results showed the use of high composition of an artificial aggregate resulted inferior strength on the concrete and 3% MAPEA in the concrete mix was highest compressive strength than other content. The modification of APEA (MAPEA) concrete increased its strength due to its surface roughness. However, the interfacial zone cracking was still found and decreased the strength of MAPEA concrete especially when it was age 28 days.

  10. Precipitation Aggregation and the Local Environment

    Science.gov (United States)

    Smalley, Mark

    The details of large-scale spatial structures of precipitation have only recently become apparent with the advent of high-resolution near-global observations from space-borne radars. As such, the relationships between these structures and the local environment and global climate are just beginning to emerge in the scientific community. Precipitation aggregates on a wide variety of scales, from individual boundary layer instabilities to extra-tropical cyclones. Separate aggregation states have been associated with widely varying precipitation rates and atmospheric states, motivating the inclusion of spatial information in hydrologic and climate models. This work adds to the body of knowledge surrounding large-scale precipitation aggregation and its driving factors by describing and demonstrating a new method of defining the spatial characteristics of precipitation events. The analysis relies on the high sensitivity and high resolution of the CloudSat Cloud Profiling Radar for the identification of precipitation with near-global coverage. The method is based on the dependence of the probability of precipitation on search area, or spatial resolution. Variations in this relationship are caused by variations in the principal characteristics of event spatial patterns: the relative spacing between events, the number density of events, and the overall fraction of precipitating scenes at high resolution. Here, this relationship is modeled by a stretched exponential containing two coefficients, that are shown to depict seasonal general circulation patterns as well as local weather. NASA's Modern-Era Retrospective analysis for Research and Applications is then used to place those spatial characteristics in the context of the local and large-scale environment. At regional scale, precipitation event density during the Amazon wet season is shown to be dependent on zonal wind speed. On a global scale, the relative spacing of shallow oceanic precipitation depends on the

  11. Studies on Strength and Behaviors of Concrete by using Pond Ash as Fine Aggregate

    Directory of Open Access Journals (Sweden)

    K. Arumugam

    2014-03-01

    Full Text Available Common river sand is expensive due to excessive cost of transportation from natural resources. Also large scale depletion of these sources creates environmental problems. In such a situation the pond ash can be an economical alternative to the river sand. Pond ash can be defined as residue and by-product of thermal power plant stations to form fine particles less than 4.75 mm. Usually, Pond ash is used in a large scale for manufacturing of bricks. Use of pond ash as a fine aggregate in concrete mortar draws serious attention of researchers. This study reports the results of some experimental studies on the use of pond ash as Fine Aggregate (FA in concrete. Super plasticiser is used to increase the workability of concrete with lower water cement ratio. The percentage of pond ash added by weight was 0, 20, 30, 40 and 50, respectively as replacement of FA used in concrete. Experiments were carried out to determine the compressive, splitting tensile and flexural strength with those of conventional concrete made with pond ash as fine aggregate. The various mechanical properties were studied and compared with natural fine aggregate. The test results obtained indicate that pond ash of marginal quantity as partial sand replacement has beneficial effect on the mechanical properties. The strength development for various percentages (0-50% replacement of fine aggregate with pond ash can easily be equated to the strength development of normal concrete with various ages. The properties of aggregates were also compared. Test result indicates that the workability of pond ash concrete is good and the strength characteristics are comparable to those of conventional concrete.

  12. es on Strength Characteristics of Pond Ash Replaced Fibre Reinforced Pavement Quality Concrete

    Directory of Open Access Journals (Sweden)

    Anand G Patil

    2015-08-01

    Full Text Available Energy consumption and generation is increasing day by day due to rapid industrialization & urbanization. A major portion of the energy is generated by Thermal Power Plants. Pond ash (PA and other by-products from these plants are disposed in large quantities. Pond ash utilization helps to reduce the consumption of natural resources. Hence there is scope for using Pond ash as Fine Aggregate (FA. Use of alternative material in concrete such as industrial by-products like Coal Ash (Fly Ash and Pond Ash is eco-friendly. This study reports the results of experimental studies carried out on the use of Pond ash as Fine Aggregate (FA in concrete with and without fibre reinforcement. The properties of Pond Ash were compared to the standard sand. The pond ash added by weight is 10%,20%,30%,40%,50% and 60% respectively as replacement of FA in concrete and 2% low tensile steel fibre was used for reinforcement. Experiments carried out indicate that Pond ash as partial replacement of sand has beneficial effect on the mechanical properties. The strength properties are determined for various percentages (10-60% of replacement of Fine Aggregate with Pond ash with and without fibre reinforcement. The test results indicate that the optimum PA replacement is 20% for both the cases.

  13. Compressive and flexural strength of expanded perlite aggregate mortar subjected to high temperatures

    Science.gov (United States)

    Zulkifeli, Muhamad Faqrul Hisham bin Mohd; Saman@Hj Mohamed, Hamidah binti Mohd

    2017-08-01

    Work on thermal resistant of outer structures of buildings is one of the solution to reduce death, damages and properties loss in fire cases. Structures protected with thermal resistant materials can delay or avoid failure and collapse during fire. Hence, establishment of skin cladding with advance materials to protect the structure of buildings is a necessary action. Expanded perlite is a good insulation material which can be used as aggregate replacement in mortar. This study is to study on mortar mechanical properties of flexural and compressive strength subjected to elevated temperatures using expanded perlite aggregate (EPA). This study involved experimental work which was developing mortar with sand replacement by volume of 0%, 10%, 20%, 30% and 40% of EPA and cured for 56 days. The mortars then exposed to 200°C, 400 °C, 700 °C and 1000 °C. Flexural and compressive strength of the mortar were tested. The tests showed that there were increased of flexural and compressive strength at 200°C, and constantly decreased when subjected to 400°C, 700°C and 1000 °C. There were also variation of strengths at different percentages of EPA replacement. Highest compressive strength and flexural strength recorded were both at 200 °C with 65.52 MPa and 21.34 MPa respectively. The study conclude that by using EPA as aggregate replacement was ineffective below elevated temperatures but increased the performance of the mortar at elevated temperatures.

  14. Aggregation of Diesel Contaminated Soil for Bioremediation

    Institute of Scientific and Technical Information of China (English)

    Yu Ying; Shi Xiu-hong; Li Song; Xu Jing-gang

    2014-01-01

    Diesel contaminated soil (DCS) contained a large amount of the hydrocarbons and salt which was dominated by soluble sodium chloride. Aggregation process which made the desired aggregate size distribution could speed up the degradation rate of the hydrocarbons since the aggregated DCS had better physical characteristics than the non-aggregated material. Artificial aggregation increased pores >30 µm by approximately 5% and reduced pores <1 µm by 5%, but did not change the percentage of the pores between 1 and 30 µm. The saturated hydraulic conductivity of non-aggregated DCS was 5×10-6 m• s-l, but it increased to 1×10-5 m• s-l after aggregation. The compression index of the non-aggregated DCS was 0.0186; however, the artificial aggregates with and without lime were 0.031 and 0.028, respectively. DCS could be piled 0.2 m deep without artificial aggregation; however, it could be applied 0.28 m deep when artificial aggregates were formed without limiting O2 transport.

  15. ATPase domain and interdomain linker play a key role in aggregation of mitochondrial Hsp70 chaperone Ssc1.

    Science.gov (United States)

    Blamowska, Marta; Sichting, Martin; Mapa, Koyeli; Mokranjac, Dejana; Neupert, Walter; Hell, Kai

    2010-02-12

    The co-chaperone Hep1 is required to prevent the aggregation of mitochondrial Hsp70 proteins. We have analyzed the interaction of Hep1 with mitochondrial Hsp70 (Ssc1) and the determinants in Ssc1 that make it prone to aggregation. The ATPase and peptide binding domain (PBD) of Hsp70 proteins are connected by a linker segment that mediates interdomain communication between the domains. We show here that the minimal Hep1 binding entity of Ssc1 consists of the ATPase domain and the interdomain linker. In the absence of Hep1, the ATPase domain with the interdomain linker had the tendency to aggregate, in contrast to the ATPase domain with the mutated linker segment or without linker, and in contrast to the PBD. The closest homolog of Ssc1, bacterial DnaK, and a Ssc1 chimera, in which a segment of the ATPase domain of Ssc1 was replaced by the corresponding segment from DnaK, did not aggregate in Delta hep1 mitochondria. The propensity to aggregate appears to be a specific property of the mitochondrial Hsp70 proteins. The ATPase domain in combination with the interdomain linker is crucial for aggregation of Ssc1. In conclusion, our results suggest that interdomain communication makes Ssc1 prone to aggregation. Hep1 counteracts aggregation by binding to this aggregation-prone conformer.

  16. Bouncing Behavior of Microscopic Dust Aggregates

    CERN Document Server

    Seizinger, Alexander

    2013-01-01

    Context: Bouncing collisions of dust aggregates within the protoplanetary may have a significant impact on the growth process of planetesimals. Yet, the conditions that result in bouncing are not very well understood. Existing simulations studying the bouncing behavior used aggregates with an artificial, very regular internal structure. Aims: Here, we study the bouncing behavior of sub-mm dust aggregates that are constructed applying different sample preparation methods. We analyze how the internal structure of the aggregate alters the collisional outcome and determine the influence of aggregate size, porosity, collision velocity, and impact parameter. Methods: We use molecular dynamics simulations where the individual aggregates are treated as spheres that are made up of several hundred thousand individual monomers. The simulations are run on GPUs. Results: Statistical bulk properties and thus bouncing behavior of sub-mm dust aggregates depend heavily on the preparation method. In particular, there is no uni...

  17. Durability and Shrinkage Characteristics of Self-Compacting Concretes Containing Recycled Coarse and/or Fine Aggregates

    Directory of Open Access Journals (Sweden)

    Mehmet Gesoglu

    2015-01-01

    Full Text Available This paper addresses durability and shrinkage performance of the self-compacting concretes (SCCs in which natural coarse aggregate (NCA and/or natural fine aggregate (NFA were replaced by recycled coarse aggregate (RCA and/or recycled fine aggregate (RFA, respectively. A total of 16 SCCs were produced and classified into four series, each of which included four mixes designed with two water to binder (w/b ratios of 0.3 and 0.43 and two silica fume replacement levels of 0 and 10%. Durability properties of SCCs were tested for rapid chloride penetration, water sorptivity, gas permeability, and water permeability at 56 days. Also, drying shrinkage accompanied by the water loss and restrained shrinkage of SCCs were monitored over 56 days of drying period. Test results revealed that incorporating recycled coarse and/or fine aggregates aggravated the durability properties of SCCs tested in this study. The drying shrinkage and restrained shrinkage cracking of recycled aggregate (RA concretes had significantly poorer performance than natural aggregate (NA concretes. The time of cracking greatly prolonged as the RAs were used along with the increase in water/binder ratio.

  18. Registry data trends of total ankle replacement use.

    Science.gov (United States)

    Roukis, Thomas S; Prissel, Mark A

    2013-01-01

    Joint arthroplasty registry data are meaningful when evaluating the outcomes of total joint replacement, because they provide unbiased objective information regarding survivorship and incidence of use. Critical evaluation of the registry data information will benefit the surgeon, patient, and industry. However, the implementation and acceptance of registry data for total ankle replacement has lagged behind that of hip and knee implant arthroplasty. Currently, several countries have national joint arthroplasty registries, with only some procuring information for total ankle replacement. We performed an electronic search to identify publications and worldwide registry databanks with pertinent information specific to total ankle replacement to determine the type of prostheses used and usage trends over time. We identified worldwide registry data from 33 countries, with details pertinent to total ankle replacement identified in only 6 countries. The obtained information was arbitrarily stratified into 3 distinct periods: 2000 to 2006, 2007 to 2010, and 2011. Within these study periods, the data from 13 total ankle replacement systems involving 3,980 ankles were identified. The vast majority (97%) of the reported ankle replacements were 3-component, mobile-bearing, uncemented prostheses. Three usage trends were identified: initial robust embracement followed by abrupt disuse, minimal use, and initial embracement followed by sustained growth in implantation. Before the widespread acceptance of new total ankle replacements, the United States should scrutinize and learn from the international registry data and develop its own national joint registry that would include total ankle replacement. Caution against the adoption of newly released prostheses, especially those without readily available revision components, is recommended.

  19. Long-range Rydberg molecules, Rydberg macrodimers and Rydberg aggregates in an ultracold Cs gas. Investigation of long-range interactions between atoms in electronically highly excited statesRydberg Few-Body Physics

    Science.gov (United States)

    Saßmannshausen, Heiner; Deiglmayr, Johannes; Merkt, Frédéric

    2016-12-01

    We present an overview of our recent investigations of long-range interactions in an ultracold Cs Rydberg gas. These interactions are studied by high-resolution photoassociation spectroscopy, using excitation close to one-photon transitions into np3/2 Rydberg states with pulsed and continuous-wave ultraviolet laser radiation, and lead to the formation of long-range Cs2 molecules. We observe two types of molecular resonances. The first type originates from the correlated excitation of two atoms into Rydberg-atom-pair states interacting at long range via multipole-multipole interactions. The second type results from the interaction of one atom excited to a Rydberg state with one atom in the electronic ground state. Which type of resonances is observed in the experiments depends on the laser intensity and frequency and on the pulse sequences used to prepare the Rydberg states. We obtain insights into both types of molecular resonances by modelling the interaction potentials, using a multipole expansion of the long-range interaction for the first type of resonances and a Fermi-contact pseudo-potential for the second type of resonances. We analyse the relation of these long-range molecular resonances to molecular Rydberg states and ion-pair states, and discuss their decay channels into atomic and molecular ions. In experiments carried out with a two-colour two-photon excitation scheme, we observe a large enhancement of Rydberg-excitation probability, which we interpret as a saturable autocatalytic antiblockade phenomenon.

  20. PERCOLATION OF RANDOM CYLINDER AGGREGATES

    Directory of Open Access Journals (Sweden)

    Dominique Jeulin

    2011-05-01

    Full Text Available The percolation threshold ρc of Boolean models of cylinders with their axis parallel to a given direction is studied by means of simulations. An efficient method of construction of percolating connected components was developed, and is applied to one or two scales Boolean model, in order to simulate the presence of aggregates. The invariance of the percolation threshold with respect to affine transformations in the common direction of the axis of cylinders is approximately satisfied on simulations. The prediction of the model (ρc close to 0.16 is consistent with experimental measurements on plasma spray coatings, which motivated this study.

  1. Urbanization, Ikization, and Replacement Dynamics

    CERN Document Server

    Chen, Yanguang

    2015-01-01

    The phenomenon of Iks was first found by anthropologists and biologists, but it is actually a problem of human geography. However, it has not yet drawn extensive attention of geographers. In this paper, a hypothesis of ikization is presented that sudden and violent change of geographical environments results in dismantling of traditional culture, which then result in collective depravity of a nationality. By quantitative analysis and mathematical modeling, the causality between urbanization and ikization is discussed, and the theory of replacement dynamics is employed to interpret the process of ikization. Urbanization is in essence a nonlinear process of population replacement. Urbanization may result in ikization because that the migration of population from rural regions to urban regions always give rise to abrupt changes of geographical environments and traditional culture. It is necessary to protect the geographical environment against disruption, and to inherit and develop traditional culture in order t...

  2. [MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT].

    Science.gov (United States)

    Tabata, Minoru

    2016-03-01

    Minimally invasive aortic valve replacement (MIAVR) is defined as aortic valve replacement avoiding full sternotomy. Common approaches include a partial sternotomy right thoracotomy, and a parasternal approach. MIAVR has been shown to have advantages over conventional AVR such as shorter length of stay and smaller amount of blood transfusion and better cosmesis. However, it is also known to have disadvantages such as longer cardiopulmonary bypass and aortic cross-clamp times and potential complications related to peripheral cannulation. Appropriate patient selection is very important. Since the procedure is more complex than conventional AVR, more intensive teamwork in the operating room is essential. Additionally, a team approach during postoperative management is critical to maximize the benefits of MIAVR.

  3. Mitochondrial Replacement: Ethics And Identity

    OpenAIRE

    Wrigley, Anthony; Wilkinson, Stephen; Appleby, John B

    2015-01-01

    Mitochondrial replacement techniques (MRTs) have the potential to allow prospective parents who are at risk of passing on debilitating or even life-threatening mitochondrial disorders to have healthy children to whom they are genetically related. Ethical concerns have however been raised about these techniques. This article focuses on one aspect of the ethical debate, the question of whether there is any moral difference between the two types of MRT proposed: Pronuclear Transfer (PNT) and Mat...

  4. Dynamics in Alzheimer's disease: the role of peptide flexibility on amyloid beta aggregation

    Science.gov (United States)

    Antonieta Sanchez Farran, Maria; Maranas, Janna

    2010-03-01

    Aggregates of the amyloid beta peptide (Aβ) are thought to trigger brain cell death in Alzheimer's patients. Two different types of Aβ aggregates have been identified: soluble, and insoluble. Soluble aggregates are formed in early stages of peptide association, whereas insoluble aggregates are the final state of aggregation. Interestingly, it is the soluble aggregates, not the insoluble ones, which correlate with disease progression. Despite the relevance of soluble aggregates as a target for Alzheimer's disease, their mechanism of formation is unknown. The role of local flexibility in protein function has recently received attention: in this study we ask if local flexibility plays a similar role in how soluble aggregates form. To answer this question, we perform all-atom molecular dynamics simulations of the wild-type Aβ monomer, and two mutated forms that vary in their ability to form soluble aggregates. We find that enhanced flexibility facilitates the formation and availability of nucleation sites by allowing the peptide to more easily access the conformations most favorable to association. Peptides with high flexibility show larger conformational changes than less flexible peptides, the extent of these changes could determine the ability of Aβ to self associate.

  5. Protein aggregation in bacteria: the thin boundary between functionality and toxicity.

    Science.gov (United States)

    Bednarska, Natalia G; Schymkowitz, Joost; Rousseau, Frederic; Van Eldere, Johan

    2013-09-01

    Misfolding and aggregation of proteins have a negative impact on all living organisms. In recent years, aggregation has been studied in detail due to its involvement in neurodegenerative diseases, including Alzheimer's, Parkinson's and Huntington's diseases, and type II diabetes--all associated with accumulation of amyloid fibrils. This research highlighted the central importance of protein homeostasis, or proteostasis for short, defined as the cellular state in which the proteome is both stable and functional. It implicates an equilibrium between synthesis, folding, trafficking, aggregation, disaggregation and degradation. In accordance with the eukaryotic systems, it has been documented that protein aggregation also reduces fitness of bacterial cells, but although our understanding of the cellular protein quality control systems is perhaps most detailed in bacteria, the use of bacterial proteostasis as a drug target remains little explored. Here we describe protein aggregation as a normal physiological process and its role in bacterial virulence and we shed light on how bacteria defend themselves against the toxic threat of aggregates. We review the impact of aggregates on bacterial viability and look at the ways that bacteria use to maintain a balance between aggregation and functionality. The proteostasis in bacteria can be interrupted via overexpression of proteins, certain antibiotics such as aminoglycosides, as well as antimicrobial peptides--all leading to loss of cell viability. Therefore intracellular protein aggregation and disruption of proteostatic balance in bacteria open up another strategy that should be explored towards the discovery of new antimicrobials.

  6. Replacing magnets at the LHC

    CERN Multimedia

    LHC, LSI2, Point 4

    2013-01-01

    CERN engineers have been working through the night this week to move the final replacement dipole magnets into position on the Large Hadron Collider (LHC). Though there are several still to go, the teams expect to have completed the task by the end of this month. Dipole magnets bend the paths of particles as they travel around the circular accelerator. Of the LHC's 1232 dipoles – each 15 metres long and weighing 35 tonnes – 15 are being replaced as part of the long shutdown of CERN's accelerator complex. These 15 magnets suffered wear and tear during the LHC's first 4-year run. Three quadrupole-magnet assemblies – which help to focus particles into a tight beam – have also been replaced. Moving such heavy magnets requires specially adapted cranes and trailers both above and below ground. There are several access points on the LHC. Some, such as the 100-metre vertical access shaft down to the ALICE experiment, are equipped with lifts to allow technical personnel and visitors down to the caverns. Other ...

  7. Results of Austin Moore replacement.

    Directory of Open Access Journals (Sweden)

    Jadhav A

    1996-04-01

    Full Text Available Forty cases of Austin Moore Replacement done for transcervical fractures of the femur in patients were reviewed after a period of 12 to 48 months postoperatively (mean 26 mth. 30 cases (75% had mild to severe pain of non-infective origin, starting as early as 6 months postoperatively. This was irrespective of the make, size or position (varus/valgus of the prosthesis. Though the Aufranc and Sweet clinical scoring was satisfactory in 65% cases, radiological evidence of complications like sinking, protrusion, etc. were seen in majority of the cases. Calcar resorption was seen in 34 cases (85% as early as 4 months postoperatively. Results of THR and bipolar replacement done for transcervical fractures in recent literature show 85% pain-free cases at 5 years. We feel that Austin Moore Replacement should be reserved for patients more than 65 years of age and those who are less active or debilitated because of other factors, because of increased acetabular wear with time in the younger individual. This is corroborated by unsatisfactory results in patients less than 65 years of age (p < 0.05.

  8. The caudal septum replacement graft.

    Science.gov (United States)

    Foda, Hossam M T

    2008-01-01

    To describe a technique for reconstructing the lost tip support in cases involving caudal septal and premaxillary deficiencies. The study included 120 patients with aesthetic and functional nasal problems resulting from the loss of caudal septal and premaxillary support. An external rhinoplasty approach was performed to reconstruct the lost support using a cartilaginous caudal septum replacement graft and premaxillary augmentation with Mersilene mesh. The majority of cases (75%) involved revisions in patients who had previously undergone 1 or more nasal surgical procedures. A caudal septum replacement graft was combined with premaxillary augmentation in 93 patients (77.5%). The mean follow-up period was 3 years (range, 1-12 years). The technique succeeded in correcting the external nasal deformities in all patients and resulted in a significant improvement in breathing in 74 patients (86%) with preoperative nasal obstruction. There were no cases of infection, displacement, or extrusion. The caudal septum replacement graft proved to be very effective in restoring the lost tip support in patients with caudal septal deficiency. Combining the graft with premaxillary augmentation using Mersilene mesh helped increase support and stability over long-term follow-up.

  9. Aggregation kinetics of a simulated telechelic polymer

    Science.gov (United States)

    Wilson, Mark; Rabinovitch, Avinoam; Baljon, Arlette R. C.

    2011-12-01

    We investigate the aggregation kinetics of a simulated telechelic polymer gel. In the hybrid molecular dynamics (MD)/Monte Carlo (MC) algorithm, aggregates of associating end groups form and break according to MC rules, while the position of the polymers in space is dictated by MD. As a result, the aggregate sizes change over time. In order to describe this aggregation process, we employ master equations. They define changes in the number of aggregates of a certain size in terms of reaction rates. These reaction rates indicate the likelihood that two aggregates combine to form a large one, or that a large aggregate splits into two smaller parts. The reaction rates are obtained from the simulations for a range of temperatures. Our results indicate that the rates are not only temperature dependent, but also a function of the sizes of the aggregates involved in the reaction. Using the measured rates, solutions to the master equations are shown to be stable and in agreement with the aggregate size distribution, as obtained directly from simulation data. Furthermore, we show how temperature-induced variations in these rates give rise to the observed changes in the aggregate distribution that characterizes the sol-gel transition.

  10. Pyridine Aggregation in Helium Nanodroplets

    Science.gov (United States)

    Nieto, Pablo; Poerschke, Torsten; Habig, Daniel; Schwaab, Gerhard; Havenith, Martina

    2012-06-01

    Pyridine crystals show the unusual property of isotopic polymorphism. Experimentally it has been observed that deuterated pyridine crystals exist in two phases while non-deuterated pyridine does not show a phase transition. Therefore, although isotopic substitution is the smallest possible modification of a molecule it greatly affects the stability of pyridine crystals. A possible experimental approach in order to understand this striking effect might be the study of pyridine aggregation for small clusters. By embedding the clusters in helium nanodroplets the aggregates can be stabilized and studied by means of Infrared Depletion Spectroscopy. Pyridine oligomers were investigated in the C-H asymmetric vibration region (2980-3100 cm-1) using this experimental technique. The number of molecules for the clusters responsibles for each band were determined by means of pick-up curves as well as mass sensitive depletion spectra. Furthermore, the intensity dependence of the different bands on applying a dc electric field was studied. The assignment of the different structures for pyridine clusters on the basis of these measurements were also carried out. S. Crawford et al., Angew. Chem. Int. Ed., 48, 755 (2009).

  11. Specification aggregate quarry expansion: a case study demonstrating sustainable management of natural aggregate resources

    Science.gov (United States)

    Langer, William H.; Tucker, M.L.

    2003-01-01

    Many countries, provinces, territories, or states in the European Union, Australia, Canada, the United States, and elsewhere have begun implementing sustainability programs, but most of those programs stop short of sustainable management of aggregate resources. Sustainable practices do not always have to be conducted under the title of sustainability. This case study describes how Lafarge, a large multinational construction materials supplier, implemented the principles of sustainability even though there was an absence of existing local government policies or procedures addressing sustainable resource management. Jefferson County, Colorado, USA, is one of three counties in the six-county Denver, Colorado, region that has potentially available sources of crushed stone. Crushed stone comprises 30 percent of the aggregate produced in the area and plays a major role in regional aggregate resource needs. Jefferson County is home to four of the five crushed stone operations in the Denver region. Lafarge operates one of those four quarries. Lafarge recently proposed to expand its reserves by exchanging company-owned land for existing dedicated open space land adjacent to their quarry but owned by Jefferson County. A similar proposal submitted about 10 years earlier had been denied. Contrary to the earlier proposal, which was predicated on public relations, the new proposal was predicated on public trust. Although not explicitly managed under the moniker of sustainability, Lafarge used basic management principles that embody the tenets of sustainability. To achieve the goals of sustainable aggregate management where no governmental policies existed, Lafarge not only assumed their role of being a responsible corporate and environmental member of the community, but also assumed the role of facilitator to encourage and enable other stakeholders to responsibly resolve legitimate concerns regarding the Lafarge quarry proposal. Lafarge successfully presented an enlightened

  12. Salto Talaris fixed-bearing total ankle replacement system.

    Science.gov (United States)

    Rush, Shannon M; Todd, Nicholas

    2013-01-01

    The Salto Talaris total ankle replacement is an anatomically designed fixed bearing prosthesis available in the United States based on the successful design of the mobile-bearing Salto prosthesis available outside the United States. The original mobile-bearing design was modified and the mobile-bearing was transferred to the precision instrumentation at the trial phase evaluation. Instrumentation and technique allow the surgeon to determine the functional joint axis before final implantation. The Salto Talaris total ankle replacement design blends minimal bone resection and optimizes surface area, cortical contact, and ultra-high molecular weight polyethylene conformity. The authors present an overview of the Salto Talaris total ankle replacement surgical technique and pearls for successful application.

  13. Byproduct aggregate. Copper slag aggregate, ferronickel slag aggregate; Fukusan kotsuzai. Do suragu kotsuzai, fuero nikkeru suragu kotsuzai

    Energy Technology Data Exchange (ETDEWEB)

    Kajiwara, Toshitaka

    1998-08-10

    Copper slag aggregate and ferronickel slag aggregate has not only usual substitute of sand or crushed sand but many features unlike sand or unlike crushed sand. It has many features unlike sand or crushed sand. It seems that especially, behavior of the particulates minute is features of deserving in addition, the examination in future. Of course, one feature also consists on the merit on the demerit by the use. And, copper slag aggregate, ferronickel slag aggregate have also limited the production place at the output of about 2 million annual production tons. These features are utilized, and in addition, wants to teach and want to receive the wider usage. (NEDO)

  14. Fusion following failed total ankle replacement.

    Science.gov (United States)

    Wünschel, Markus; Leichtle, Ulf G; Leichtle, Carmen I; Walter, Christian; Mittag, Falk; Arlt, Eva; Suckel, Andreas

    2013-04-01

    Although mid- to long-term results after total ankle replacement have improved because of available second- and third-generation devices, failure of total ankle replacement is still more common compared with total hip replacement and total knee replacement. The portfolio of available total ankle replacement revision component options is small. Furthermore, the bone stock of the tibiotalar region is scarce making it difficult and in some situations impossible to perform revision total ankle replacement. In these cases tibiotalar and tibiotalocalcaneal fusions are valuable options. This article describes which surgical procedures should be performed depending on the initial situation and gives detailed advice on surgical technique, postoperative care, and clinical results.

  15. Replacing gasoline with corn ethanol results in significant environmental problem-shifting.

    Science.gov (United States)

    Yang, Yi; Bae, Junghan; Kim, Junbeum; Suh, Sangwon

    2012-04-03

    Previous studies on the life-cycle environmental impacts of corn ethanol and gasoline focused almost exclusively on energy balance and greenhouse gas (GHG) emissions and largely overlooked the influence of regional differences in agricultural practices. This study compares the environmental impact of gasoline and E85 taking into consideration 12 different environmental impacts and regional differences among 19 corn-growing states. Results show that E85 does not outperform gasoline when a wide spectrum of impacts is considered. If the impacts are aggregated using weights developed by the National Institute of Standards and Technology (NIST), overall, E85 generates approximately 6% to 108% (23% on average) greater impact compared with gasoline, depending on where corn is produced, primarily because corn production induces significant eutrophication impacts and requires intensive irrigation. If GHG emissions from the indirect land use changes are considered, the differences increase to between 16% and 118% (33% on average). Our study indicates that replacing gasoline with corn ethanol may only result in shifting the net environmental impacts primarily toward increased eutrophication and greater water scarcity. These results suggest that the environmental criteria used in the Energy Independence and Security Act (EISA) be re-evaluated to include additional categories of environmental impact beyond GHG emissions.

  16. Bonding Behavior of Deformed Steel Rebars in Sustainable Concrete Containing both Fine and Coarse Recycled Aggregates.

    Science.gov (United States)

    Kim, Sun-Woo; Park, Wan-Shin; Jang, Young-Il; Jang, Seok-Joon; Yun, Hyun-Do

    2017-09-14

    In order to assess the bond behavior of deformed steel rebars in recycled-aggregate concrete (RAC) incorporating both fine and coarse recycled aggregate, pull-out tests were carried out in this study on 16-mm diameter deformed steel rebars embedded concentrically in RAC. The concrete was designed using equivalently mixed proportions of both recycled coarse aggregate and recycled fine aggregate. The tests employed five types of recycled aggregate replacement combinations and three types of rebar placement orientation (i.e., vertical bars and two-tiered and three-tiered horizontal bars). Based on the pull-out test results, the maximum bond strength tended to decrease and the slip at the maximum bond strength increased as the average water absorption of the aggregate increased, irrespective of the rebar orientation or placement location within the concrete member. The pull-out test results for the horizontal steel rebars embedded in RAC indicate that the casting position effect could be determined from the mid-depth of the concrete member, irrespective of the member's height. The normalized bond versus slip relationship between the deformed rebar and the RAC could be predicted using an empirical model based on regression analysis of the experimental data.

  17. Controversy in mitral valve repair, resection or chordal replacement?

    Science.gov (United States)

    Sawazaki, Masaru; Tomari, Shiro; Zaikokuji, Kenta; Imaeda, Yusuke

    2014-10-01

    Mitral valve plasty has superseded valve replacement as the standard technique for treating degenerative mitral valve prolapse. Quadrangular resection is considered the gold standard for posterior leaflet prolapse. Chordal replacement was first developed to treat the anterior leaflet and subsequently became widely used for the posterior leaflet, after which a new version of posterior leaflet resection was developed that did not involve local annular plication. In the era of the mini-thoracotomy, the premeasured loop technique is simple to adopt and is as durable as quadrangular resection. However, there is controversy surrounding whether resection or chordal replacement is the optimal technique. The resection technique is curative because it removes the main pathologic lesion. The disadvantage of the resection is that it can be complicated and often requires advanced surgical skills. In contrast, chordal replacement is not pathologically curative because it leaves behind a redundant leaflet. However, the long-term results appear to be equivalent in many reports. Functionally, chordal replacement retains greater posterior leaflet motion with a lower trans-mitral pressure gradient than quadrangular resection. Moreover, chordal replacement is simple and yields uniform results. The optimal technique depends on whether the anterior leaflet or posterior leaflet is involved, the Barlow or non-Barlow disease state, and whether a mini-thoracotomy or standard sternotomy approach is used. For mitral valve repair, the most superior and reliable technique for the posterior leaflet is resection using the newer resection technique with a sternotomy approach, which requires a skilled surgeon.

  18. Role of multicellular aggregates in biofilm formation

    DEFF Research Database (Denmark)

    Kragh, Kasper N.; Hutchison, Jaime B.; Melaugh, Gavin

    2016-01-01

    In traditional models of in vitro biofilm development, individual bacterial cells seed a surface, multiply, and mature into multicellular, three-dimensional structures. Much research has been devoted to elucidating the mechanisms governing the initial attachment of single cells to surfaces. However......, in natural environments and during infection, bacterial cells tend to clump as multicellular aggregates, and biofilms can also slough off aggregates as a part of the dispersal process. This makes it likely that biofilms are often seeded by aggregates and single cells, yet how these aggregates impact biofilm...... initiation and development is not known. Here we use a combination of experimental and computational approaches to determine the relative fitness of single cells and preformed aggregates during early development of Pseudomonas aeruginosa biofilms. We find that the relative fitness of aggregates depends...

  19. A vertically resolved model for phytoplankton aggregation

    Indian Academy of Sciences (India)

    Iris Kriest; Geoffrey T Evans

    2000-12-01

    This work presents models of the vertical distribution and flux of phytoplankton aggregates, including changes with time in the distribution of aggregate sizes and sinking speeds. The distribution of sizes is described by two parameters, the mass and number of aggregates, which greatly reduces the computational cost of the models. Simple experiments demonstrate the effects of aggregation on the timing and depth distribution of primary production and export. A more detailed ecological model is applied to sites in the Arabian Sea; it demonstrates that aggregation can be important for deep sedimentation even when its effect on surface concentrations is small, and it presents the difference in timing between settlement of aggregates and fecal pellets.

  20. Nature of the optical band shapes in polymethine dyes and H-aggregates: dozy chaos and excitons. Comparison with dimers, H*- and J-aggregates

    Science.gov (United States)

    2017-01-01

    Results on the theoretical explanation of the shape of optical bands in polymethine dyes, their dimers and aggregates are summarized. The theoretical dependence of the shape of optical bands for the dye monomers in the vinylogous series in line with a change in the solvent polarity is considered. A simple physical (analytical) model of the shape of optical absorption bands in H-aggregates of polymethine dyes is developed based on taking the dozy-chaos dynamics of the transient state and the Frenkel exciton effect in the theory of molecular quantum transitions into account. As an example, the details of the experimental shape of one of the known H-bands are well reproduced by this analytical model under the assumption that the main optical chromophore of H-aggregates is a tetramer resulting from the two most probable processes of inelastic binary collisions in sequence: first, monomers between themselves, and then, between the resulting dimers. The obtained results indicate that in contrast with the compact structure of J-aggregates (brickwork structure), the structure of H-aggregates is not the compact pack-of-cards structure, as stated in the literature, but a loose alternate structure. Based on this theoretical model, a simple general (analytical) method for treating the more complex shapes of optical bands in polymethine dyes in comparison with the H-band under consideration is proposed. This method mirrors the physical process of molecular aggregates forming in liquid solutions: aggregates are generated in the most probable processes of inelastic multiple binary collisions between polymethine species generally differing in complexity. The results obtained are given against a background of the theoretical results on the shape of optical bands in polymethine dyes and their aggregates (dimers, H*- and J-aggregates) previously obtained by V.V.E. PMID:28572984

  1. Dynamics of Symmetric Conserved Mass Aggregation Model on Complex Networks

    Institute of Scientific and Technical Information of China (English)

    HUA Da-Yin

    2009-01-01

    We investigate the dynamical behaviour of the aggregation process in the symmetric conserved mass aggregation model under three different topological structures. The dispersion σ(t, L) = (∑i(mi - ρ0)2/L)1/2 is defined to describe the dynamical behaviour where ρ0 is the density of particle and mi is the particle number on a site. It is found numerically that for a regular lattice and a scale-free network, σ(t, L) follows a power-law scaling σ(t, L) ~ tδ1 and σ(t, L) ~ tδ4 from a random initial condition to the stationary states, respectively. However, for a small-world network, there are two power-law scaling regimes, σ(t, L) ~ tδ2 when t<T and a(t, L) ~ tδ3 when tT. Moreover, it is found numerically that δ2 is near to δ1 for small rewiring probability q, and δ3 hardly changes with varying q and it is almost the same as δ4. We speculate that the aggregation of the connection degree accelerates the mass aggregation in the initial relaxation stage and the existence of the long-distance interactions in the complex networks results in the acceleration of the mass aggregation when tT for the small-world networks. We also show that the relaxation time T follows a power-law scaling τ Lz and σ(t, L) in the stationary state follows a power-law σs(L) ~ Lσ for three different structures.

  2. Aggregates in the Temporal Query Language TQuel,

    Science.gov (United States)

    1987-07-27

    makes it possible to define both standard and unique aggregates in a rigorous way. Ceri and Gottlob present 43 prVPW t TW WRJR V P P V * a translation...from a subset of SQL that includes aggregates into relational algebra, thereby defining an operational semantics for SQL aggregates [Ceri & Gottlob ...Zvi, J. The Time Relational Model. Ph). Diss. Computer Science Department, UCLA, 1982. (Ceri & Gotlob 19851 Ceri, S. and G. Gottlob . Translating SQL

  3. CALiPER Special Summary Report: Retail Replacement Lamp Testing

    Energy Technology Data Exchange (ETDEWEB)

    None

    2011-04-01

    CALiPER testing has evaluated many products for commercial lighting markets and found some excellent performers. However, many of these are not available on the retail market. This special testing was undertaken to identify and test solid-state lighting (SSL) replacement lamp products that are available to the general public through retail stores and websites.

  4. Inhibition of protein aggregation in vitro and in vivo by a natural osmoprotectant.

    Science.gov (United States)

    Ignatova, Zoya; Gierasch, Lila M

    2006-09-05

    Small organic molecules termed osmolytes are harnessed by a variety of cell types in a wide range of organisms to counter unfavorable physiological conditions that challenge protein stability and function. Using a well characterized reporter system that we developed to allow in vivo observations, we have explored how the osmolyte proline influences the stability and aggregation of a model aggregation-prone protein, P39A cellular retinoic acid-binding protein. Strikingly, we find that the natural osmolyte proline abrogates aggregation both in vitro and in vivo (in an Escherichia coli expression system). Importantly, proline also prevented aggregation of constructs containing exon 1 of huntingtin with extended polyglutamine tracts. Although compatible osmolytes are known to stabilize the native state, our results point to a destabilizing effect of proline on partially folded states and early aggregates and a solubilizing effect on the native state. Because proline is believed to act through a combination of solvophobic backbone interactions and favorable side-chain interactions that are not specific to a particular sequence or structure, the observed effect is likely to be general. Thus, the osmolyte proline may be protective against biomedically important protein aggregates that are hallmarks of several late-onset neurodegenerative diseases including Huntington's, Alzheimer's, and Parkinson's. In addition, these results should be of practical importance because they may enable protein expression at higher efficiency under conditions where aggregation competes with proper folding.

  5. Experimental replacement of aragonite by hydroxyapatite

    Science.gov (United States)

    Kasioptas, A.; Perdikouri, C.; Geisler, T.; Putnis, A.

    2009-04-01

    the PO43- molecule. The bands that show the highest intensity are those corresponding to three and four 18O atoms substituting for 16O in the PO4 molecule. A non-equilibrated phosphate solution was also used in the replacement experiments in order to observe the simultaneous processes of replacement and H218O-P16O4 exchange in solution. Differences in the intensity of the four vibration modes offer kinetic information on the replacement mechanism when compared with kinetic data of the H218O-P16O4 exchange reaction obtained from in situ Raman investigations (Geisler et al., 2008). Geisler T., Kasioptas A., Menneken M., Perdikouri C., Putnis A, Journal of Geochemical Exploration (2008) Kasioptas A., Perdikouri C., Putnis C.V., Putnis A, Mineralogical Magazine 72, 77-80 (2008) Putnis A., Putnis C.V, Journal of Solid State Chemistry 180, 1783-1786 (2007)

  6. Radiology of total hip replacement

    Energy Technology Data Exchange (ETDEWEB)

    Griffiths, H.J.; Lovelock, J.E.; McCollister Evarts, C.; Geyer, D.

    1984-06-01

    The radiology of total hip replacement (THR) and its complications is reviewed in conjunction with a long-term follow-up study on 402 patients with 501 prostheses. The indications, contraindications, biomechanics, and operative management of these patients is discussed. Clinical complications such as deep vein thrombosis, pulmonary embolism, and hemorrhage are mentioned. Postoperative infections including granulomatous pseudotumors, dislocations and fractures, true loosening of the prosthesis, and heterotopic bone formation (HBF) are discussed and illustrated. The importance of differentiating the lucent line from true loosening is stressed. Mechanical and other clinical complications which are largely ignored by radiologists are also discussed. The uses of arthrography and bone scanning are included.

  7. [Proximal and total femur replacement].

    Science.gov (United States)

    Pennekamp, P H; Wirtz, D C; Dürr, H R

    2012-07-01

    Reconstruction of segmental bone defects of the proximal femur following wide tumor resection or revision arthroplasty. Aggressive benign or primary malignant bone tumors of the proximal femur; destructive metastases; massive segmental bone defects of the proximal femur; periprosthetic fractures. Local infection; very short life expectancy (acetabular bone stock. Anterolateral approach. Exposure and detachment of the iliopsoas and gluteus medius muscle from the proximal femur with a sufficient safety margin to the bone; distal transsection of the vastus lateralis/intermedius and rectus femoris muscle according to the extraosseous tumor extension; distal femur osteotomy al least 3 cm beyond the farthest point of tumor extension; in case of total femur replacement, additional lateral arthrotomy of the knee with resection of the ligaments and menisci; reaming of the medullary canal after securing the shaft with a Verbrugge clamp; trial assembly and reduction followed by the definitive implantation of the prosthesis with adjustment of the femoral neck anteversion in 5° increments; soft tissue reconstruction and fixation to an attachment tube covering the prosthesis; in case of total femur replacement, the preparation of the tibia is followed by the coupling of the tibial and femoral components. Infection prophylaxis, 20 kg partial weight bearing, continuous passive motion. A total of 20  patients with proximal femur replacement and 2 patients with total femur replacement implanted between June 2007 and December 2011 were retrospectively reviewed. Three patients had primary malignant bone tumors, while 19 patients underwent resection for metastatic disease. The mean age at surgery was 62.0 ± 18.1 years (18-82 years). Fifteen patients with a mean follow-up of 20.3 ± 17.2 months (4-51 months) were studied. Among the 22 cases, periprosthetic infection occurred in 3 patients (13.6%), dislocation in 2 patients (9.1%). Evaluation of the functional

  8. Flexural Behaviour Of Reinforced Concrete Beams Containing Expanded Glass As Lightweight Aggregates

    Science.gov (United States)

    Khatib, Jamal; Jefimiuk, Adrian; Khatib, Sammy

    2015-12-01

    The flexural properties of reinforced concrete beams containing expanded glass as a partial fine aggregate (sand) replacement are investigated. Four concrete mixes were employed to conduct this study. The fine aggregate was replaced with 0%, 25%, 50% and 100% (by volume) expanded glass. The results suggest that the incorporation of 50% expanded glass increased the workability of the concrete. The compressive strength was decreasing linearly with the increasing amount of expanded glass. The ductility of the concrete beam significantly improved with the incorporation of the expanded glass. However, the load-carrying capacity of the beam and load at which the first crack occurs was reduced. It was concluded that the inclusion of expanded glass in structural concrete applications is feasible.

  9. Population balance modeling of antibodies aggregation kinetics.

    Science.gov (United States)

    Arosio, Paolo; Rima, Simonetta; Lattuada, Marco; Morbidelli, Massimo

    2012-06-21

    The aggregates morphology and the aggregation kinetics of a model monoclonal antibody under acidic conditions have been investigated. Growth occurs via irreversible cluster-cluster coagulation forming compact, fractal aggregates with fractal dimension of 2.6. We measured the time evolution of the average radius of gyration, , and the average hydrodynamic radius, , by in situ light scattering, and simulated the aggregation kinetics by a modified Smoluchowski's population balance equations. The analysis indicates that aggregation does not occur under diffusive control, and allows quantification of effective intermolecular interactions, expressed in terms of the Fuchs stability ratio (W). In particular, by introducing a dimensionless time weighed on W, the time evolutions of measured under various operating conditions (temperature, pH, type and concentration of salt) collapse on a single master curve. The analysis applies also to data reported in the literature when growth by cluster-cluster coagulation dominates, showing a certain level of generality in the antibodies aggregation behavior. The quantification of the stability ratio gives important physical insights into the process, including the Arrhenius dependence of the aggregation rate constant and the relationship between monomer-monomer and cluster-cluster interactions. Particularly, it is found that the reactivity of non-native monomers is larger than that of non-native aggregates, likely due to the reduction of the number of available hydrophobic patches during aggregation.

  10. Pre-aggregation for Probability Distributions

    DEFF Research Database (Denmark)

    Timko, Igor; Dyreson, Curtis E.; Pedersen, Torben Bach

    Motivated by the increasing need to analyze complex uncertain multidimensional data (e.g., in order to optimize and personalize location-based services), this paper proposes novel types of {\\em probabilistic} OLAP queries that operate on aggregate values that are probability distributions...... and the techniques to process these queries. The paper also presents the methods for computing the probability distributions, which enables pre-aggregation, and for using the pre-aggregated distributions for further aggregation. In order to achieve good time and space efficiency, the methods perform approximate...... multidimensional data analysis that is considered in this paper (i.e., approximate processing of probabilistic OLAP queries over probability distributions)....

  11. Aggregate growth in a protoplanetary disk

    Science.gov (United States)

    Xiang, Chuchu; Carballido, Augusto; Matthews, Lorin; Hyde, Truell

    2017-01-01

    We present a method to model the growth of neutral and charged dusts in a turbulent protoplanetary disk, and analyze their collision probabilities. Coagulation of dust aggregates plays an important role in the formation of planets and is of key importance to the evolution of protoplanetary disks. In our method, the temporal evolution of the dusts is followed by Monte Carlo algorithm, and the inter-particle interactions are calculated by Aggregate_Builder (AB), which is a code used to model the collision process of aggregates. First an aggregate library is built and all the aggregates are binned according to their sizes. In each iteration, the collision rate for aggregates from any two bins are computed, which determines the time it takes for the next collision to happen and which two aggregates are selected for collision. Then the AB codes are used to calculate the interaction of the two aggregates. The relative velocity between the two aggregates is the vector sum of Brownian velocity and the turbulent velocity. The latter is calculated by ATHENA, which is a grid-based code for astrophysical magnetohydrodynamics. In each iteration, it’s determined whether the two aggregates hit or miss. In the case of hit, it either sticks or bounces as determined by the critical velocity. As a result, the neutral aggregates are more porous than the charged ones. For a certain size of incoming aggregates, the neutral ones have a higher collision probability than the charged ones. Also, similarly-sized aggregates have lower collision probabilities than aggregates with large size dispersions. This research enables us to determine which physical properties have a greater impact on the collision rate. By tracing the dust size distribution, we can identify the stage when they settle out to the mid-plane and how long it takes to develop to that stage. In the hit-stick regime, our results are consistent with the experiments which shows that when the velocity is smaller than the

  12. Aggregated Dynamic Dataflow Graph Generation and Visualization

    Directory of Open Access Journals (Sweden)

    I. Szabó

    2013-12-01

    Full Text Available Aggregated Dynamic Dataflow Graphs can assist programmers to uncover the main data paths of a given algorithm. This information can be useful when scaling a singlethreaded program into a multi-core architecture. The amount of data movements is crucial when targeting for cache incoherent and/or heterogeneous platforms. This paper presents two methods for generating function-level Aggregated Dynamic Dataflow Graphs. Instruction level trace log was used as a basis, which was generated by Microsoft Giano processor simulator platform. Top-down aggregation strategy and relational database was used to speed up the generation of different views of the aggregated dataflow and call graphs.

  13. Macroeconomic susceptibility, inflation, and aggregate supply

    Science.gov (United States)

    Hawkins, Raymond J.

    2017-03-01

    We unify aggregate-supply dynamics as a time-dependent susceptibility-mediated relationship between inflation and aggregate economic output. In addition to representing well various observations of inflation-output dynamics this parsimonious formalism provides a straightforward derivation of popular representations of aggregate-supply dynamics and a natural basis for economic-agent expectations as an element of inflation formation. Our formalism also illuminates questions of causality and time-correlation that challenge central banks for whom aggregate-supply dynamics is a key constraint in their goal of achieving macroeconomic stability.

  14. Pre-aggregation for Probability Distributions

    DEFF Research Database (Denmark)

    Timko, Igor; Dyreson, Curtis E.; Pedersen, Torben Bach

    Motivated by the increasing need to analyze complex uncertain multidimensional data (e.g., in order to optimize and personalize location-based services), this paper proposes novel types of {\\em probabilistic} OLAP queries that operate on aggregate values that are probability distributions...... and the techniques to process these queries. The paper also presents the methods for computing the probability distributions, which enables pre-aggregation, and for using the pre-aggregated distributions for further aggregation. In order to achieve good time and space efficiency, the methods perform approximate...... multidimensional data analysis that is considered in this paper (i.e., approximate processing of probabilistic OLAP queries over probability distributions)....

  15. Morphological classification of nanoceramic aggregates

    Science.gov (United States)

    Crosta, Giovanni F.; Kang, Bongwoo; Ospina, Carolina; Sung, Changmo

    2005-01-01

    Aluminum silicate nanoaggregates grown at near-room temperature on an organic template under a variety of experimental conditions have been imaged by transmission electron microscopy. Images have been automatically classified by an algorithm based on "spectrum enhancement", multivariate statistics and supervised optimization. Spectrum enhancement consists of subtracting, in the log scale, a known function of wavenumber from the angle averaged power spectral density of the image. Enhanced spectra of each image, after polynomial interpolation, have been regarded as morphological descriptors and as such submitted to principal components analysis nested with a multiobjective parameter optimization algorithm. The latter has maximized pairwise discrimination between classes of materials. The role of the organic template and of a reaction parameter on aggregate morphology has been assessed at two magnification scales. Classification results have also been related to crystal structure data derived from selected area electron diffraction patterns.

  16. Collisional Aggregation due to Turbulence

    CERN Document Server

    Pumir, Alain

    2015-01-01

    Collisions between particles suspended in a fluid play an important role in many physical processes. As an example, collisions of microscopic water droplets in clouds are a necessary step in the production of macroscopic raindrops. Collisions of dust grains are also conjectured to be important for planet formation in the gas surrounding young stars, and also to play a role in the dynamics of sand storms. In these processes, collisions are favoured by fast turbulent motions. Here we review recent advances in the understanding of collisional aggregation due to turbulence. We discuss the role of fractal clustering of particles, and caustic singularities of their velocities. We also discuss limitations of the Smoluchowski equation for modelling these processes. These advances lead to a semi-quantitative understanding on the influence of turbulence on collision rates, and point to deficiencies in the current understanding of rainfall and planet formation.

  17. Colloid Release from Soil Aggregates

    DEFF Research Database (Denmark)

    Vendelboe, Anders Lindblad; Møldrup, Per; Schjønning, Per;

    2012-01-01

    The content of water-dispersible colloids (WDC) has a major impact on soil functions and structural stability. In addition, the presence of mobile colloids may increase the risk of colloid-facilitated transport of strongly sorbing environmental contaminants. The WDC content was measured in 39 soils......, using laser diffraction, by agitating the samples using a wet-dispersion unit. This approach eliminated the need for long sedimentation times required by the more classical end-over-end shaking approach and provided information about the time-dependent release of WDC. The total clay content of the soils...... ranged from 0.1 to 0.44 kg kg−1. The WDC content was measured on air-dry and moist 1- to 2-mm aggregates. The WDC content at a reference time was highly correlated to the total clay content (r > 0.91, P soils. Only for two sites was the WDC content correlated to the content of clay...

  18. Supramolecular Assembly of Complementary Cyanine Salt J-Aggregates

    KAUST Repository

    Li, Zhong’an

    2015-09-09

    An understanding of structure–property relationships in cyanine dyes is critical for their design and application. Anionic and cationic cyanines can be organized into complementary cyanine salts, offering potential building blocks to modulate their intra/intermolecular interactions in the solid state. Here, we demonstrate how the structures of these complementary salts can be tuned to achieve highly ordered J-type supramolecular aggregate structures of heptamethine dyes in crystalline solids.

  19. Supramolecular Assembly of Complementary Cyanine Salt J-Aggregates.

    Science.gov (United States)

    Li, Zhong'an; Mukhopadhyay, Sukrit; Jang, Sei-Hum; Brédas, Jean-Luc; Jen, Alex K-Y

    2015-09-23

    An understanding of structure-property relationships in cyanine dyes is critical for their design and application. Anionic and cationic cyanines can be organized into complementary cyanine salts, offering potential building blocks to modulate their intra/intermolecular interactions in the solid state. Here, we demonstrate how the structures of these complementary salts can be tuned to achieve highly ordered J-type supramolecular aggregate structures of heptamethine dyes in crystalline solids.

  20. Characterization of effects of thermal property of aggregate on the carbon footprint of asphalt industries in China

    Directory of Open Access Journals (Sweden)

    Ali Jamshidi

    2017-04-01

    Full Text Available In this study, the effects of the thermal properties of asphalt binders and aggregate materials were characterized in terms of the specific heat capacity (C for energy consumption and environmental footprints of hot mix asphalt (HMA and warm mix asphalt (WMA. Asphalt mixes produced using low-C aggregate are found to be more energy-efficient and environmental friendly, irrespective of the binder type and construction technology. Therefore, different fractions of aggregate blends were replaced with the aggregate provided from a low-C source or sustainable source. Analysis of energy consumption clearly indicated that the specific energy and environmental footprints decrease linearly as the low-C aggregate content increases. The amount of energy saving realized in the asphalt industries by the use of low-C aggregate is significant on a national scale in China. In this regard, China was chosen as a case study. Analysis of fuel requirement clearly indicated that the production of WMA using high thermal sensitivity aggregate can yield significant energy saving sufficient to fuel 44,007 to 664,880 Chinese households per year. Therefore, use of low C aggregate in asphalt mix production can be adopted as a strategy to produce WMA and HMA.

  1. Modeling compressive strength of recycled aggregate concrete by Artificial Neural Network, Model Tree and Non-linear Regression

    Directory of Open Access Journals (Sweden)

    Neela Deshpande

    2014-12-01

    Full Text Available In the recent past Artificial Neural Networks (ANN have emerged out as a promising technique for predicting compressive strength of concrete. In the present study back propagation was used to predict the 28 day compressive strength of recycled aggregate concrete (RAC along with two other data driven techniques namely Model Tree (MT and Non-linear Regression (NLR. Recycled aggregate is the current need of the hour owing to its environmental friendly aspect of re-use of the construction waste. The study observed that, prediction of 28 day compressive strength of RAC was done better by ANN than NLR and MT. The input parameters were cubic meter proportions of Cement, Natural fine aggregate, Natural coarse Aggregates, recycled aggregates, Admixture and Water (also called as raw data. The study also concluded that ANN performs better when non-dimensional parameters like Sand–Aggregate ratio, Water–total materials ratio, Aggregate–Cement ratio, Water–Cement ratio and Replacement ratio of natural aggregates by recycled aggregates, were used as additional input parameters. Study of each network developed using raw data and each non dimensional parameter facilitated in studying the impact of each parameter on the performance of the models developed using ANN, MT and NLR as well as performance of the ANN models developed with limited number of inputs. The results indicate that ANN learn from the examples and grasp the fundamental domain rules governing strength of concrete.

  2. The Physics of Amyloid Aggregation and Templating in Prions

    Science.gov (United States)

    Cox, Daniel

    2012-02-01

    The problem of self-assembled amyloid aggregation of proteins in structures with beta-strands perpendicular to a one dimensional grown axis is interesting at a fundamental level (is this the most generic end state of proteins?), from a biological level (if the self-assembly can be regulated it is of use in contexts like spider silk and bacterial colony formation), for human public health (aggregation unregulated induces diseases like mad cow and Alzheimer's), and for possible materials applications (e.g., in tissue scaffolding). In this presentation, I will review the work of my group in examining the possibility that the left-handed beta helix (LHBH) structure can be the building block of the aggregates of mammalian prion and yeast prion proteins. I will also discuss our efforts to assess the possibility of a novel pH driven structural switch between LHBH and alpha-helical forms in the ordered half of the mammalian prion protein, and now the possibly pH stabilized LHBH structure can template aggregate growth of the disordered half of the protein, identified in numerous experimental studies as most relevant to disease.

  3. Commercial and Multifamily Building Tenant Energy Usage Aggregation and Privacy

    Energy Technology Data Exchange (ETDEWEB)

    Livingston, Olga V.; Pulsipher, Trenton C.; Wang, Na

    2014-11-17

    In a number of cities and states, building owners are required to disclose and/or benchmark their building energy use. This requires the building owner to possess monthly whole-building energy usage information, which can be challenging for buildings in which individual tenants have their own utility meters and accounts with the utility. Some utilities and utility regulators have turned to aggregation of customer data as a way to give building owners the whole-building energy usage data while protecting customer privacy. However, no utilities or regulators appear to have conducted a concerted statistical, cybersecurity, and privacy analysis to justify the level of aggregation selected. Therefore, the Tennant Data Aggregation Task was established to help utilities address these issues and provide recommendations as well as a theoretical justification of the aggregation threshold. This study is focused on the use case of submitting data for ENERGY STAR Portfolio Manager (ESPM), but it also looks at other potential use cases for monthly energy consumption data.

  4. Effect of Cultivation on Soil Organic Matter and Aggregate Stability

    Institute of Scientific and Technical Information of China (English)

    A.WILLIAMS; XING Bao-Shan; P.VENEMAN

    2005-01-01

    Agricultural sustainability relates directly to maintaining or enhancing soil quality. Soil quality studies in Canada during the 1980's showed that loss of soil organic matter (SOM) and soil aggregate stability was standard features of non-sustainable land management in agroecosystems. In this study total soil organic carbon (SOC), particulate organic matter (POM), POM-C as a percentage of total SOC, and aggregate stability were determined for three cultivated fields and three adjacent grassland fields to assess the impact of conventional agricultural management on soil quality. POM was investigated using solid-state 13C nuclear magnetic resonance (NMR) to determine any qualitative differences that may be attributed to cultivation. Results show a highly significant loss in total SOC, POM and aggregate stability in the cultivated fields as compared to the grassland fields and a significant loss of POM-C as a percentage of total SOC.Integrated results of the NMR spectra of the POM show a loss in carbohydrate-C and an increase in aromatic-C in the cultivated fields, which translates to a loss of biological lability in the organic matter. Conventional cultivation decreased the quantity and quality of SOM and caused a loss in aggregate stability resulting in an overall decline in soil quality.

  5. B Plant process piping replacement feasibility study

    Energy Technology Data Exchange (ETDEWEB)

    Howden, G.F.

    1996-02-07

    Reports on the feasibility of replacing existing embedded process piping with new more corrosion resistant piping between cells and between cells and a hot pipe trench of a Hanford Site style canyon facility. Provides concepts for replacement piping installation, and use of robotics to replace the use of the canyon crane as the primary means of performing/supporting facility modifications (eg, cell lining, pipe replacement, equipment reinstallation) and operational maintenenace.

  6. REMINDER REPLACEMENT OF FRENCH CARDS

    CERN Multimedia

    Human Resources Division; Cards.Service@cern.ch

    2001-01-01

    The French Ministry of Foreign Affairs is currently replacing all diplomatic cards, special cards and employment permits («attestations de fonctions») held by members of the personnel and their families. These cards are replaced by secure, computerized equivalents. The old cards may no longer be used after 31 December 2001. For the purposes of the handover, members of the personnel must go personally to the cards office (33/1-015) between 8h30 and 12h30, in order to fill in a «fiche individuelle» form, taking the following documents for themselves and members of their families already in possession of a French card : A recent identity photograph in 4.5 cm x 3.5 cm format, the French card in their possession, an A4 photocopy of the same French card, certified by the cards office as being a true copy. Those members of the personnel whose cards (and/or cards belonging to members of their families) are shortly due to expire, or have recently done so, are also requested...

  7. Total hip replacement in dancers.

    Science.gov (United States)

    Buyls, Inge R A E; Rietveld, A B M Boni; Ourila, Tiia; Emerton, Mark E; Bird, H A

    2013-04-01

    A case report of a professional contemporary dancer who successfully returned to the stage after bilateral total hip replacements (THR) for osteoarthritis is presented, together with her own commentary and a retrospective cohort study of total hip replacements in dancers. In the presented cohort, there were no post-operative dislocations or infections, the original pain had been relieved, rehabilitation was objectively normal and all resumed their dance (teaching) activities. Nevertheless, they were disappointed about the prolonged rehabilitation. Due to their high demands as professional dancers, post-operative expectations were too optimistic in view of the usual quick and favourable results of THR in the older and less physically active, general population. In all dancers with unilateral osteoarthritis, the left hip was involved, which may reflect the tendency to use the left leg as standing leg and be suggestive that strenuous physical activity may lead to osteoarthritis. Better rehabilitation guidelines are needed for dancer patients undergoing THR, especially drawing their attention to realistic post-operative expectations.

  8. Thrombolytic therapy reduces red blood cell aggregation in plasma without affecting intrinsic aggregability.

    Science.gov (United States)

    Ben-Ami, R; Sheinman, G; Yedgar, S; Eldor, A; Roth, A; Berliner, A S; Barshtein, G

    2002-03-15

    Red blood cell (RBC) aggregation may contribute to occlusion of the coronary microcirculation during myocardial infarction. We studied the effect of thrombolytic therapy on RBC aggregation in patients with acute myocardial infarction (AMI). Compared with patients with myocardial infarction who did not receive thrombolytic therapy, those treated with systemic thrombolysis exhibited significantly reduced RBC aggregation, reduced plasma fibrinogen levels and increased plasma D-dimer levels. Using measurement of RBC aggregation in a standardized dextran-500 solution, reduction in RBC aggregation after thrombolysis was shown to be plasma dependent. Thrombolytic therapy had no direct effect on intrinsic RBC aggregability in patients with AMI. We conclude that thrombolytic therapy has rheologic consequences that may contribute to its overall efficacy. Inhibition of RBC aggregation by thrombolytic therapy may result from the degradation of fibrinogen, a key factor in the formation of RBC aggregates, and from the generation of fibrinogen degradation products capable of disaggregating RBCs.

  9. Optimizing the Mixing Proportion with Neural Networks Based on Genetic Algorithms for Recycled Aggregate Concrete

    Directory of Open Access Journals (Sweden)

    Sangyong Kim

    2013-01-01

    Full Text Available This research aims to optimize the mixing proportion of recycled aggregate concrete (RAC using neural networks (NNs based on genetic algorithms (GAs for increasing the use of recycled aggregate (RA. NN and GA were used to predict the compressive strength of the concrete at 28 days. And sensitivity analysis of the NN based on GA was used to find the mixing ratio of RAC. The mixing criteria for RAC were determined and the replacement ratio of RAs was identified. This research reveal that the proposed method, which is NN based on GA, is proper for optimizing appropriate mixing proportion of RAC. Also, this method would help the construction engineers to utilize the recycled aggregate and reduce the concrete waste in construction process.

  10. Microstructure and Mechanical Properties of Recycled Aggregate Concrete in Seawater Environment

    Directory of Open Access Journals (Sweden)

    Pengjun Yue

    2013-01-01

    Full Text Available This study aims to conduct research about the microstructure and basic properties of recycled aggregate concrete under seawater corrosion. Concrete specimens were fabricated and tested with different replacement percentages of 0%, 30%, and 60% after immersing in seawater for 4, 8, 12, and 16 months, respectively. The basic properties of recycled aggregate concrete (RAC including the compressive strength, the elastic modulus, and chloride penetration depth were explicitly investigated. And the microstructure of recycled concrete aggregate (RCA was revealed to find the seawater corrosion by using scanning electron microscope (SEM. The results showed that higher amount of the RCA means more porosity and less strength, which could lower both the compressive strength and resistance to chloride penetration. This research could be a guide in theoretical and numerical analysis for the design of RAC structures.

  11. Performance Evaluation of Stone Mastic Asphalt and Hot Mix Asphalt Mixtures Containing Recycled Concrete Aggregate

    Directory of Open Access Journals (Sweden)

    Mohammad Saeed Pourtahmasb

    2014-01-01

    Full Text Available Environmental and economic considerations have encouraged civil engineers to find ways to reuse recycled materials in new constructions. The current paper presents an experimental research on the possibility of utilizing recycled concrete aggregates (RCA in stone mastic asphalt (SMA and hot mix asphalt (HMA mixtures. Three categories of RCA in various percentages were mixed with virgin granite aggregates to produce SMA and HMA specimens. The obtained results indicated that, regardless of the RCA particular sizes, the use of RCA to replace virgin aggregates increased the needed binder content in the asphalt mixtures. Moreover, it was found that even though the volumetric and mechanical properties of the asphalt mixtures are highly affected by the sizes and percentages of the RCA but, based on the demands of the project and traffic volume, utilizing specific amounts of RCA in both types of mixtures could easily satisfy the standard requirements.

  12. Functional Importance of Tyrosine 294 and the Catalytic Selectivity for the Bis-Fe(IV) State of MauG Revealed by Replacement of This Axial Heme Ligand with Histidine

    Energy Technology Data Exchange (ETDEWEB)

    Tarboush, Nafez Abu; Jensen, Lyndal M.R.; Feng, Manliang; Tachikawa, Hiroyasu; Wilmot, Carrie M.; Davidson, Victor L. (UMMC); (UMM); (Jackson)

    2010-12-07

    The diheme enzyme MauG catalyzes the posttranslational modification of a precursor protein of methylamine dehydrogenase (preMADH) to complete the biosynthesis of its protein-derived tryptophan tryptophylquinone (TTQ) cofactor. It catalyzes three sequential two-electron oxidation reactions which proceed through a high-valent bis-Fe(IV) redox state. Tyr294, the unusual distal axial ligand of one c-type heme, was mutated to His, and the crystal structure of Y294H MauG in complex with preMADH reveals that this heme now has His-His axial ligation. Y294H MauG is able to interact with preMADH and participate in interprotein electron transfer, but it is unable to catalyze the TTQ biosynthesis reactions that require the bis-Fe(IV) state. This mutation affects not only the redox properties of the six-coordinate heme but also the redox and CO-binding properties of the five-coordinate heme, despite the 21 {angstrom} separation of the heme iron centers. This highlights the communication between the hemes which in wild-type MauG behave as a single diheme unit. Spectroscopic data suggest that Y294H MauG can stabilize a high-valent redox state equivalent to Fe(V), but it appears to be an Fe(IV)=O/{pi} radical at the five-coordinate heme rather than the bis-Fe(IV) state. This compound I-like intermediate does not catalyze TTQ biosynthesis, demonstrating that the bis-Fe(IV) state, which is stabilized by Tyr294, is specifically required for this reaction. The TTQ biosynthetic reactions catalyzed by wild-type MauG do not occur via direct contact with the Fe(IV)=O heme but via long-range electron transfer through the six-coordinate heme. Thus, a critical feature of the bis-Fe(IV) species may be that it shortens the electron transfer distance from preMADH to a high-valent heme iron.

  13. Preformed Seeds Modulate Native Insulin Aggregation Kinetics.

    Science.gov (United States)

    Dutta, Colina; Yang, Mu; Long, Fei; Shahbazian-Yassar, Reza; Tiwari, Ashutosh

    2015-12-10

    Insulin aggregates under storage conditions via disulfide interchange reaction. It is also known to form aggregates at the site of repeated injections in diabetes patients, leading to injection amyloidosis. This has fueled research in pharmaceutical and biotechnology industry as well as in academia to understand factors that modulate insulin stability and aggregation. The main aim of this study is to understand the factors that modulate aggregation propensity of insulin under conditions close to physiological and measure effect of "seeds" on aggregation kinetics. We explored the aggregation kinetics of insulin at pH 7.2 and 37 °C in the presence of disulfide-reducing agent dithiothreitol (DTT), using spectroscopy (UV-visible, fluorescence, and Fourier transform infrared spectroscopy) and microscopy (scanning electron microscopy, atomic force microscopy) techniques. We prepared insulin "seeds" by incubating disulfide-reduced insulin at pH 7.2 and 37 °C for varying lengths of time (10 min to 12 h). These seeds were added to the native protein and nucleation-dependent aggregation kinetics was measured. Aggregation kinetics was fastest in the presence of 10 min seeds suggesting they were nascent. Interestingly, intermediate seeds (30 min to 4 h incubation) resulted in formation of transient fibrils in 4 h that converted to amorphous aggregates upon longer incubation of 24 h. Overall, the results show that insulin under disulfide reducing conditions at pH and temperature close to physiological favors amorphous aggregate formation and seed "maturity" plays an important role in nucleation dependent aggregation kinetics.

  14. Mechanical and thermal properties of prepacked aggregate concrete incorporating palm oil fuel ash

    Indian Academy of Sciences (India)

    HOSSEIN MOHAMMADHOSSEINI; A S M ABDUL AWAL; ABDUL RAHMAN MOHD SAM

    2016-10-01

    Prepacked aggregate concrete (PAC) is a special type of concrete which is made by placing coarse aggregate in a formwork and injecting a grout either by pump or under the gravity force to fill the voids. Use of pozzolanic materials in conventional concrete has become increasingly extensive, and this trend is expected to continue in PAC as well. Palm oil fuel ash (POFA) is one of these pozzolanic ash, which has been recognized as a good pozzolanic material. This paper presents the experimental results of the performance behaviour of POFA in developing physical and mechanical properties of prepacked aggregate concrete. Four concrete mixes namely,prepacked concrete with 100% OPC as a control, and PAC with 10, 20 and 30% POFA were cast, and thetemperature growth due to heat of hydration and heat transfer in all the mixtures was recorded. It has been found that POFA significantly reduces the temperature rise in prepacked aggregate concrete and delay the transfer of heat to the concrete body. The compressive and tensile strengths, however, increased with replacement up to20% POFA. The results obtained and the observation made in this study suggest that the replacement of OPC by POFA is beneficial, particularly for prepacked mass concrete where thermal cracking due to extreme heat rise is of great concern.

  15. Therapy of hypoparathyroidism by replacement with parathyroid hormone

    DEFF Research Database (Denmark)

    Rejnmark, Lars; Underbjerg, Line; Sikjaer, Tanja

    2014-01-01

    Hypoparathyroidism (HypoPT) is a state of hypocalcemia due to inappropriate low levels of parathyroid hormone (PTH). HypoPT is normally treated by calcium supplements and activated vitamin D analogues. Although plasma calcium is normalized in response to conventional therapy, quality of life (Qo......L) seems impaired and patients are at increased risk of renal complications. A number of studies have suggested subcutaneous injections with PTH as an alternative therapy. By replacement with the missing hormone, urinary calcium may be lowered and QoL may improve. PTH replacement therapy (PTH-RT) possesses...

  16. Towards High-Performance Network Application Identification With Aggregate-Flow Cache

    Directory of Open Access Journals (Sweden)

    Fei He

    2011-05-01

    Full Text Available Classifying network traffic according to their application-layer protocols is an important task in modern networks for traffic management and network security. Existing payload-based or statistical methods ofapplication identification cannot meet the demand of both high performance and accurate identificationat the same time. We propose an application identification framework that classifies traffic at aggregateflow level leveraging aggregate-flow cache. A detailed traffic classifier designed based on this framework is illustrated to improve the throughput of payload-based identification methods. We further optimize the classifier by proposing an efficient design of aggregate-flow cache. The cache design employs a frequency-based, recency-aware replacement algorithm based on the analysis of temporal locality of aggregate-flow cache. Experiments on real-world traces show that our traffic classifier with aggregateflow cache can reduce up to 95% workload of backend identification engine. The proposed cache replacement algorithm outperforms well-known replacement algorithms, and achieves 90% of the optimal performance using only 15% of memory. The throughput of a payload-based identification system, L7-filter [1], is increased by up to 5.1 times by using our traffic classifier design.

  17. Natural osmolytes remodel the aggregation pathway of mutant huntingtin exon 1.

    Science.gov (United States)

    Borwankar, Tejas; Röthlein, Christoph; Zhang, Gong; Techen, Anne; Dosche, Carsten; Ignatova, Zoya

    2011-03-29

    In response to stress small organic compounds termed osmolytes are ubiquitously accumulated in all cell types to regulate the intracellular solvent quality and to counteract the deleterious effect on the stability and function of cellular proteins. Given the evidence that destabilization of the native state of a protein either by mutation or by environmental changes triggers the aggregation in the neurodegenerative pathologies, the modulation of the intracellular solute composition with osmolytes is an attractive strategy to stabilize an aggregating protein. Here we report the effect of three natural osmolytes on the in vivo and in vitro aggregation landscape of huntingtin exon 1 implicated in the Huntington's disease. Trimethylamine N-oxide (TMAO) and proline redirect amyloid fibrillogenesis of the pathological huntingtin exon 1 to nonamyloidogenic amorphous assemblies via two dissimilar molecular mechanisms. TMAO causes a rapid formation of bulky amorphous aggregates with minimally exposed surface area, whereas proline solubilizes the monomer and suppresses the accumulation of early transient aggregates. Conversely, glycine-betaine enhances fibrillization in a fashion reminiscent of the genesis of functional amyloids. Strikingly, none of the natural osmolytes can completely abrogate the aggregate formation; however, they redirect the amyloidogenesis into alternative, nontoxic aggregate species. Our study reveals new insights into the complex interactions of osmoprotectants with polyQ aggregates.

  18. Stages and conformations of the Tau repeat domain during aggregation and its effect on neuronal toxicity.

    Science.gov (United States)

    Kumar, Satish; Tepper, Katharina; Kaniyappan, Senthilvelrajan; Biernat, Jacek; Wegmann, Susanne; Mandelkow, Eva-Maria; Müller, Daniel J; Mandelkow, Eckhard

    2014-07-18

    Several neurodegenerative diseases are characterized by the aggregation and posttranslational modifications of Tau protein. Its "repeat domain" (TauRD) is mainly responsible for the aggregation properties, and oligomeric forms are thought to dominate the toxic effects of Tau. Here we investigated the conformational transitions of this domain during oligomerization and aggregation in different states of β-propensity and pseudo-phosphorylation, using several complementary imaging and spectroscopic methods. Although the repeat domain generally aggregates more readily than full-length Tau, its aggregation was greatly slowed down by phosphorylation or pseudo-phosphorylation at the KXGS motifs, concomitant with an extended phase of oligomerization. Analogous effects were observed with pro-aggregant variants of TauRD. Oligomers became most evident in the case of the pro-aggregant mutant TauRDΔK280, as monitored by atomic force microscopy, and the fluorescence lifetime of Alexa-labeled Tau (time-correlated single photon counting (TCSPC)), consistent with its pronounced toxicity in mouse models. In cell models or primary neurons, neither oligomers nor fibrils of TauRD or TauRDΔK280 had a toxic effect, as seen by assays with lactate dehydrogenase and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, respectively. However, oligomers of pro-aggregant TauRDΔK280 specifically caused a loss of spine density in differentiated neurons, indicating a locally restricted impairment of function. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  19. Stages and Conformations of the Tau Repeat Domain during Aggregation and Its Effect on Neuronal Toxicity*

    Science.gov (United States)

    Kumar, Satish; Tepper, Katharina; Kaniyappan, Senthilvelrajan; Biernat, Jacek; Wegmann, Susanne; Mandelkow, Eva-Maria; Müller, Daniel J.; Mandelkow, Eckhard

    2014-01-01

    Several neurodegenerative diseases are characterized by the aggregation and posttranslational modifications of Tau protein. Its “repeat domain” (TauRD) is mainly responsible for the aggregation properties, and oligomeric forms are thought to dominate the toxic effects of Tau. Here we investigated the conformational transitions of this domain during oligomerization and aggregation in different states of β-propensity and pseudo-phosphorylation, using several complementary imaging and spectroscopic methods. Although the repeat domain generally aggregates more readily than full-length Tau, its aggregation was greatly slowed down by phosphorylation or pseudo-phosphorylation at the KXGS motifs, concomitant with an extended phase of oligomerization. Analogous effects were observed with pro-aggregant variants of TauRD. Oligomers became most evident in the case of the pro-aggregant mutant TauRDΔK280, as monitored by atomic force microscopy, and the fluorescence lifetime of Alexa-labeled Tau (time-correlated single photon counting (TCSPC)), consistent with its pronounced toxicity in mouse models. In cell models or primary neurons, neither oligomers nor fibrils of TauRD or TauRDΔK280 had a toxic effect, as seen by assays with lactate dehydrogenase and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, respectively. However, oligomers of pro-aggregant TauRDΔK280 specifically caused a loss of spine density in differentiated neurons, indicating a locally restricted impairment of function. PMID:24825901

  20. Studies on eco-friendly concrete incorporating industrial waste as aggregates

    Directory of Open Access Journals (Sweden)

    Nitendra Palankar

    2015-12-01

    Full Text Available The present day research is focussed on development of alternative binder materials to Ordinary Portland Cement (OPC due to huge emissions of green house gases associated with production of OPC. GGBFS-FA based geopolymer binders are an innovative alternative to OPC which can obtain high strengths apart from being eco-friendly; since its production does not involve high energy and also contributes to sustainability by using the industrial waste materials. Steel slag, an industrial by-product obtained from manufacture of steel can be identified as an alternative to natural aggregates for concrete production, since there is a possibility of acute shortage of natural aggregates in future. The present study is conducted to evaluate the performance of weathered steel slag coarse aggregates in GGBFS-FA based geopolymer concrete. GGBFS-FA geopolymer concrete with steel slag coarse aggregates are prepared by replacing natural granite aggregates at different replacement levels i.e. 0%, 25%, 50%, 75% and 100% (by volume and various fresh and mechanical properties are studied. The flexural fatigue behaviour of GGBFS-FA geopolymer concrete with steel slag is also studied in detail. Efforts are also made to model the probabilistic distribution of fatigue data of GGBFS-FA geopolymer concrete at different stress levels using two parameters Weibull distribution. The results indicated that incorporation of steel slag in GGBFS-FA geopolymer concrete resulted in slight reduction in mechanical strength. The water absorption and volume of permeable voids displayed higher values with inclusion of steel slag. Reduction in number of cycles for fatigue failure was observed in geopolymer concrete mixes containing steel slag as compared to granite aggregates. Overall, the performance of steel slag was found to be satisfactory for structural and pavement application and steel slag can be recognised as new construction material.